Sandwich structures with circular profiles, method and device for their production
Abstract
FIELD: process engineering. SUBSTANCE: invention relates to sandwich film structures with circular profile and to production of exposed structures. Proposed article feature uniform thickness and comprise at least four layers and overlapping and Nonoverlapping peripheral areas. Nonoverlapping sandwich structure doubles in overlapping layer. Proposed method comprises steps whereat flow is produced with multilayer stream of at least four layers of thermoplastic resinous materials to be fed into distributing manifold of circular spinneret to form circular multilayer stream flow and to remove said flow from circular spinneret so that circular sandwich article is produced. Besides, this invention covers the device including feeder with optional layer multiplier to create multi-stream flow in at least four channels into circular spinneret manifold and circular spinneret with at least one manifold to extrude multi-stream flow. EFFECT: production of sandwich structures, better mechanical properties. 10 cl, 11 dwg, 2 tbl, 7 ex
Term
Projected expiry 19 February 2030.
- Priority
- Filed
- Granted
- Today
- Projected expiry
10 claims: 4 independent, 6 dependent
- 1Способ получения кольцеобразной многослойной структуры, включающий стадии, на которых:создают поток с многослойным течением термопластических смолообразных материалов, причем поток с многослойным течением включает микрослоистую часть, имеющую по меньшей мере 30 слоев, и по меньшей мере один дополнительный слой на первой и второй стороне микрослоистой части, при этом микрослоистая часть имеет микрослоистую структуру;подают поток с многослойным течением в единичный распределительный канал-коллектор кольцеобразной фильеры;разделяют поток с многослойным течением по меньшей мере на два потока текучей среды, в котором по меньшей мере два потока текучей среды перемещаются в противоположных направлениях вокруг периметра распределительного канала-коллектора с образованием кольцеобразного потока с многослойным течением, один конец одного из потоков текучей среды перекрывается с одним концом еще одного потока текучей среды в области перекрывания, при этом микрослоистая структура сохраняется в области перекрывания;и удаляют кольцеобразный поток с многослойным течением из кольцеобразной фильеры с образованием кольцеобразной многослойной структуры.
- 2Способ по п.1, в котором создание потока с многослойным течением термопластических смолообразных материалов включает стадии, на которых:создают микрослоистую часть;и инкапсулируют микрослоистую часть по меньшей мере в один инкапсулирующий слой с образованием потока с многослойным течением.
- 3Способ по п.2, в котором создание микрослоистой части включает стадии, на которых:создают первый поток текучей среды, имеющий по меньшей мере два слоя;разделяют первый поток текучей среды по меньшей мере на два подпотока;и объединяют по меньшей мере два подпотока так, чтобы позиционировать первый подпоток поверх второго подпотока с образованием микрослоистой части.
- 4Способ по любому из пп.1-3, в котором поток с многослойным течением подают в единичный распределительный канал-коллектор кольцеобразной фильеры через круглый трубчатый проточный канал, имеющий дугообразное направление течения, причем дуга имеет радиус кривизны, больший, чем диаметр круглого трубчатого проточного канала.
- 5Способ по п.1, дополнительно включающий стадию, на которой создают по меньшей мере один дополнительный поток текучей среды к потоку с многослойным течением внутри кольцеобразной фильеры с использованием по меньшей мере одного дополнительного распределительного канала-коллектора.
- 6Способ по п.1, дополнительно включающий стадию, на которой:помещают кольцеобразную многослойную структуру в форме рукава внутрь литейной формы для раздувного формования и раздувают кольцеобразную многослойную структуру до контуров литейной формы.
- 7Способ по п.1, дополнительно включающий стадии, на которых:вытягивают кольцеобразную многослойную структуру в расплавленном состоянии для биаксиального ориентирования структуры;и охлаждают структуру.
- 8Способ по п.7, включающий стадии, на которых:повторно нагревают охлажденную структуру до температуры ниже температуры плавления самого высокоплавкого полимера в структуре;вытягивают структуру моноаксиально или биаксиально для ориентирования структуры;и затем охлаждают структуру.
- 9Кольцеобразное многослойное изделие, имеющее равномерную толщину и включающее перекрывающиеся и неперекрывающиеся периферические области;причем неперекрывающаяся область имеет микрослоистую часть по меньшей мере с одним дополнительным слоем на первой и второй стороне микрослоистой части, микрослоистая часть имеет по меньшей мере 30 слоев, микрослоистая часть имеет микрослоистую структуру;при этом слоистая структура неперекрывающейся области удваивается в области перекрывания, а микрослоистая структура сохраняется в области перекрывания.
- 10Устройство, содержащее:питающий блок, с необязательным мультипликатором слоев, выполненный с возможностью образования потока с многослойным течением, включающий микрослоистую часть, имеющую по меньшей мере 30 слоев, и по меньшей мере один дополнительный слой на первой и второй стороне микрослоистой части, в распределительный канал-коллектор кольцеобразной фильеры;круглый трубчатый проточный канал, имеющий дугообразное направление течения, в котором дуга имеет радиус кривизны, больший, чем диаметр круглого трубчатого проточного канала, причем круглый трубчатый проточный канал изменяет направление потока с многослойным течением, в то же время сохраняя микрослоистую структуру микрослоистой части;и кольцеобразную фильеру, имеющую по меньшей мере один распределительный канал-коллектор, которая экструдирует поток с многослойным течением, причем распределительный канал-коллектор имеет область перекрывания, при этом область перекрывания сохраняет микрослоистую структуру.
Independent claims10
198 paragraphs in 9 sections, as filed
The present invention relates to multilayer structures, and more particularly, to multilayer structures having the ring-shaped profiles, and methods and apparatus for their production.
To the modern technology of multilayer films are cast film technology and blown film. Cast film production process, which employ a method for producing flat planar type, suitable for producing flat plastic film and sheet, which often have to about 15% of the marginal ridge. As is known, methods for producing blown films provide greater flexibility with respect to changes in the width of the film or sheet on the same production line, achieving better economic performance in a small-scale specialized production, requiring frequent transition from one product to another, and typically avoid product losses, related to the boundary edge.
Multilayer films prepared by known laminating methods, typically using a monoaxial or casting process for producing a flat sheet or lamination. Coextruded structure cast film or sheet typically have from 3 to 5 layers; however known structures cast film or sheet comprising hundreds of layers. For example, early multilayer structure and methods for their preparation are known from the patent document USP 3,565,985; USP 3,557,265; and USP 3,884,606. Patent document WO 2008/008875 discloses a method for forming a related type of multi-layer structures having multiple, such as fifty to several hundreds of alternating layers of foam and film. However, the illustrated methods provide mostly just monoaxial orientation, namely in the longitudinal direction. This is a disadvantage because the resulting structure may have unbalanced mechanical properties due to the very mismatched orientation. To achieve biaxial orientation methods can be used subsequent orientation (for example, a method using a tenter frame). These additional processes are complex and expensive, and the desired degree of orientation may be different than desired, as it occurs with the dimensional limitations and at relatively low polymer temperature below the melting point of the high melting polymer in a multilayer film.
Multilayer structures having ring-shaped profiles with limited number of layers are used in numerous applications. These tubular structure with annular form include, e.g., "bubbles" in the processes of manufacturing blown films, coatings for wires or cables, the product obtained by blow molding, and a sleeve or preforms used for their manufacture, and pipe. Such products typically contain from 2 to 10 layers and the layers are annular, supplied through separate channels reservoir. Steps in the process of orientation in the extrusion of annular profiles and products, such as swelling product obtainable blow molding, or "bubble" in the preparation of blown film can be very effectively applied to provide biaxial orientation (sometimes referred to as a multiaxial orientation), whereby, It is known to produce the product of polymeric resins with a very favorable combination of physical properties.
As is well known in the art, blown film obtained by blow molding, and other ring-shaped products can be made a flow of molten polymer into the distribution channel-manifold annular die. Preparation of multiple layers generally required to design and manufacture of the channel-reservoir or core for each layer; e.g., 6-layer ring-shaped structure would be made using a spinneret having 6 individual distribution channels, reservoirs, one for each layer. Design and fabrication of these multiple distribution channels reservoir for annular structures with large number of layers is very difficult and limited in the number of ring layers, which can be created in the structure. For example, see the layering method a serial link-collectors for the annular die, as the authors said Dooley, J. and Tung, H. article "Co-extrusion" ("Coextrusion»), Encyclopedia of Polymer Science and Technology («Encyclopedia of Science and Technology of Polymers "), Publisher John Wiley & Sons, Inc., New York (2002).
Another way to obtain a multilayer structure having an annular profile, includes the use of the die with spiral core. The spinneret with a spiral core in the distribution channel-reservoir molten polymer stream fed to the distribution conduit-reservoir in the die, flows through the main channel, which spiral is cut from the entrance near the exit of the channel-collector, as described in "Extrusion Dies" ( "Extrusion die»), Design and Engineering Computations («Construction and engineering calculations"), author Walter Michaeli, 1984, pages 146-147. Flow through the distribution channel collector spiral die is not suitable for processing more than one layer of this melt in a single-channel distribution manifold, since it has determined to interrupt the flow of the melt laminate and loss of integrity of the layers.
Patent documents USP 3,308,508, 5,762,971 and 6,413,595 are forming annular multi-layered structure in the so-called lamellar ("pancake"), the die (also known as having a planar shape). The plate die comprises multiple stacked planar, or flat, the distribution channels of the collector. Each of the multiple streams of polymer melt fed into the distribution channel collector. The multilayer structure is formed by the union of several concentric melt streams after each melt stream exits its collector-distributor duct. If it is desirable to a large number of layers it required a large number of stacked-channel reservoirs. This can lead to a sharp drop in pressure and a longer residence time in the die. Patent documents USP 5,762,971 and 6,413,595 disclose the preparation of the final multilayer structures having a maximum of about 27 layers.
Known multilayer structure having up to 11 layers, with the spiral plate die. However, the multi-layer structure in this way are made using stacked several spiral distribution channel reservoir to form a ring-shaped die and the combined stream of current melt when they come out of the entire annular die as a whole.
Another related method for manufacturing such a multilayer structure having an annular profile, comprises the use of such annular spinneret, which is described in the patent document USP 6,685,872. As shown, in one single distribution channel annular die collector layer 3 is fed. The disclosed construction of the channel-reservoir creates an annular multi-layer structure that has an uneven contour specially provided with overlapping section, wherein the layered structure is overlapped so that the overlap region at least preserves the barrier properties of the layered structure in the non-overlapping area.
Patent document US 2008/0157443 describes a method and apparatus for producing a sleeve ("parison"). The device has a core body with lateral channel is substantially transverse with respect to the core channel. The core has an axially oriented recess in the outer surface which is in fluid communication with two fluid channels, which extend continuously in the downward direction around the core, meeting each other at the side of the core opposite the recess. In the examples disclosed structure having up to 17 layers, although discussed composite streams having up to 100 layers.
However, there is always a need to obtain laminated annular structures with an increased number of layers; applying a reduced number of distribution channels in the die-collectors; receiving annular multilayer structures having improved combinations of physical and mechanical properties; and / or reducing the number of manufacturing steps and increase the adaptability of the equipment for manufacture of annular structures.
Accordingly, the present invention is to provide a multilayer structures having ring-shaped profiles, and methods and apparatus for their production, which substantially obviate one or more problems due to limitations and disadvantages of the prior art. Various embodiments of the present invention may provide one or more of the following advantages.
One advantage of the present invention is to provide a multilayer structures having ring-shaped profile and comprising a plurality of layers, what structure may be used to produce articles having a more uniform biaxial orientation achieved in one step.
Another advantage of the present invention is to provide a multilayer structures having ring-shaped profile and comprising an increased number of layers and / or thinner layers, than the prototype annular structure using a reduced number of distribution channels reservoir.
Another advantage of one embodiment of the present invention is to provide a multilayer structures having ring-shaped profiles, which can be used to produce blown film or articles formed blow molding, in which the periphery of the structure is avoided conventional welding or the overlapping region, where the properties of the structure are undesired or worsening. Of course, it should be recognized that the products of blown film are not usually sold or used as ring-shaped structures, as they are converted from a ring-shaped structure in flat sheet products using known processing steps.
Another advantage of an alternative embodiment of the present invention is to provide film-laminated foam structures having ring-shaped profiles having cross sections that contain the foam layers and allows to reduce weight while maintaining an acceptable balance of other physical properties.
Another advantage of an alternative embodiment of the present invention is to provide a multilayer film structure having a ring-shaped profiles having cross sections that contain fibers with the inorganic filler in controlled amounts to accurately adjust the physical properties.
Another advantage of one embodiment of the present invention is to provide a multilayer structures having ring-shaped profile in which the increase in the number of layers is achieved, while substantially maintaining the integrity of layers for most layers.
In yet another alternative embodiment, another advantage of the present invention is to provide a multilayer structures having ring-shaped profiles, which are economically advantageous for a variety of applications and can be products or can be used to create them, which have at least one of: low density, improved barrier properties, increased uniformity of layers, higher strength, improved isolation, increased toughness, high tear resistance, high puncture resistance and improved tensile characteristics.
Additional features and advantages of the invention will be set forth in the description which follows and in part will be obvious from the description or may be learned by practice of the invention. Advantages of the invention will be realized and attained by the structure and method particularly pointed out in the written description and claims hereof as well as in the accompanying figures.
To achieve these advantages and in accordance with the purpose of the invention as here embodied and broadly described, the following preferred embodiments and aspects of the present invention. One embodiment is a method of producing an annular multilayer structure, comprising the steps of: generating a multilayer flow stream with at least four layers of thermoplastic resinous materials; stream is fed to a multilayer flow into the distribution channel collector annular spinneret to form an annular flow passage multilayer; and removing the annular flow passage of the multilayer annular die to form an annular multi-layered structure.
In another embodiment, the inventive method comprises the steps of creating a multilayer flow stream with at least two layers of thermoplastic resinous materials; encapsulated multilayered flow stream with at least one encapsulating layer to form a multilayer-encapsulated flow passage having at least four layers of thermoplastic resinous materials; fed encapsulated multilayer stream over a distribution channel-manifold annular die to form a multilayer annular flow passage; and removing the annular flow passage of the multilayer annular die to form an annular multi-layered structure. In additional alternative embodiments, the collector-distributor duct has a cylindrical body, tapered cylindrical housing or a planar body.
In one alternative embodiment, the distribution channel collector has a geometrical shape crosshead type, in which the flow multilayer flow is split into at least two fluid flow, wherein two streams of fluid moving in opposite directions along the periphery of the distribution channel of the collector, and in one embodiment, the fluid streams preferably overlap in one area on a modified crosshead distribution channel-reservoir. In a further alternative aspect the multilayer flow stream is fed into a single manifold conduit-reservoir through the annular spinneret round tubular flow channel having a flow direction with an arcuate shape, the arc has a radius of curvature larger than the diameter of the pipe.
In accordance with yet another alternative embodiment, the method further comprises the steps in which create at least one additional stream of fluid to flow from the multilayered passage inside the annular die with at least one additional distribution channel collector, and in this case the additional fluid flow can optionally be a stream of multilayer flow. Other optional methods of the invention further include a step in which at least one of the thermoplastic resinous materials prior to creating a multilayer flow stream with added foaming agent or an inorganic filler.
In yet another alternative embodiment of the method according to the invention comprises a step in which is placed an annular multi-layered structure in the form of a sleeve inside a mold for blow molding and inflate annular multi-layer structure to shape the mold or stretched annular multi-layered structure in a molten state to a biaxially oriented structure; and cooled structure, and optionally include reheating of the cooled structure to a temperature below the melting point of the high melting polymer structure; stretched monoaxially or biaxially structure to guide the structure; and then cooled structure. In further optional aspects of multilayer flow passage comprises more than five layers, and alternatively more than about 25 layers.
In a further alternative aspect the invention provides an annular multilayer product having a uniform thickness of at least four layers and including the overlapping and non-overlapping peripheral regions; wherein the laminated structure in the non-overlapping area doubles overlapping layer; wherein there is also an optional embodiment, the product comprises two outer covering layer on one side of the microlayered component creating at least 15 layers. In additional alternative embodiments, a multilayer blown film comprises microlayered component having at least 27 layers.
In a further alternative embodiment, the invention provides a device comprising: power supply unit, a multiplier, with optional layers, which creates a flow passage with a multilayer of at least four layers in the channel-manifold annular die; and an annular nozzle having at least one distribution conduit-reservoir which is extruded multilayer flow stream. Optionally, the device according to the invention the channel-manifold annular die is a modified cross-head design that separates the fluid flow and create areas of overlap fluid streams flow prior to extrusion with a multilayer flow, and / or has a cylindrical body, tapered cylindrical housing or a planar body.
In a further alternative embodiment of the device according to the invention, the device as described above further includes encapsulating the die between the feed unit (or, optionally, a multiplier layers) and the channel-header that encapsulates the fluid flow before entering the channel-collector, and / or additionally comprises round tubular arcuate flow path between the die and encapsulating the collecting channel and in which the inlet end of a round tubular flow channel for the fluid stream is oriented at an angle of about 90 degrees relative to the outlet end of a round tubular flow channel for fluid flow.
In a preferred alternative embodiment, inflatable multilayer films and methods of the invention provide substantially improved performance due to their preparation by an annular die, biaxially orientation (as compared with injection molding multilayer films), and / or increasing the number of layers. Basically improvements can be obtained in terms of one or more characteristics of tensile properties, toughness, extensibility and / or barrier properties. While the biaxial orientation can also be prepared for injection using a film tenter, it is a costly process step which requires significant capital investment.
It should be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to give further clarification of how the claimed invention.
The accompanying figures, which are included to provide a thorough understanding of the invention and optional embodiments, is incorporated into and constitute a part of the specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.
FIG. 1 is a schematic diagram illustrating a method for producing a multilayer blown film to the multilayer film of the composite structure in accordance with one embodiment of the present invention.
FIG. 2 is a schematic diagram illustrating a process for producing blow molding of multilayer articles of the multilayer film of the composite structure in accordance with one embodiment of the present invention.
FIG. 3 is a photograph of a cured multilayer flow passage of circular tubular flow channel with a large radius.
FIG. 4 is a photograph of a cross-sectional segment of Fig. 3.
FIG. 5 is an illustration of a spinneret having round tubular flow path with a large radius.
FIG. 6 is an illustration of a spinneret having round tubular flow path with a small radius.
Figures 7A-B are illustrations of different embodiments of the overlapping region of the annular multi-layered structure.
FIG. 8A-B are obtained with an atomic force microscope (AFM) pictures of microlayers in the overlapping and non-overlapping areas of annular multi-layered structure.
FIG. 9 is obtained by transmission electron microscopy (TEM) photograph of microlayers in overlapping annular layered structure.
Below are detailed embodiments of the present invention, examples of which are disclosed in the specification and illustrated in the accompanying figures. Those skilled in the art will appreciate that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided that they fall within the scope of the appended claims and their equivalents.
The numerical ranges in this invention include all values from the lower and to higher values, inclusive, in increments of one unit, provided that any lower value and any higher value is divided into at least two unit increments. As an example, if the reducing composition, physical or other characteristics, such as for example the thickness and density, etc., is more than 10, it is assumed that explicitly lists all individual values, such as 10, 11, 12 etc., and subranges, such as 100 to 144, 155 to 170, from 197 to 200, etc. For ranges containing values which are less than unity or containing fractional numbers greater than one (eg, 1.1, 1.5, etc.), one single increment considered as constituting 0.0001, 0.001, 0.01, or 0.1, as appropriate. For ranges containing simple unambiguous numbers less than ten (e.g., 1 to 5), the unit is typically considered increment is 0.1. Those are only examples of what is specifically intended and all possible combinations of numerical values between the lowest value and a listed highest value seen as clearly indicated herein.
A method of producing an annular multilayer structure according to the present invention and as described herein below, includes the steps in which the flow obtained and used with a multilayer flow, which is typically constructed by a multilayer coextrusion process step, and may optionally include the further process step of replicating the layers. The inventive method optionally includes the step of the encapsulation process. The claimed method includes a step in which create multilayer stream over at least four layers of thermoplastic resinous material into the distribution channel in the collector-step process with an annular spinneret. Optionally, the process step of producing blown film process or the blow molding step can be performed by adopting a multilayer flow stream exiting the annular spinneret.
The flow of the multilayer over
As used herein, the term "fluid stream" or "melt flow" with reference to a thermoplastic resinous material refers to a material, usually a polymer or polymeric material, as described further below, softened by heating (heated to or above the melting point or up to the glass transition temperature material, i.e. the temperature at which the material becomes sufficiently fluid to flow into the equipment relevant to this embodiment) suitable for thermoplastic processing and flowable under sufficient pressure. The fluid flow can be created in several ways known in the art. Preferably, the fluid flow creates an extruder (i.e., extrusion), optionally comprising a gear pump for flow uniformity, but it can also be created as the end product of other process steps using thermal plasticization of the gear pump. Multilayer flow passage of the layers of thermoplastic resinous materials may be constructed of two or more fluid streams layers by known methods, including primarily the well-known coextrusion techniques, and, optionally, also by known methods replicating layers as discussed in more detail below.
Multiple streams of thermoplastic polymeric material can be co-extruded by applying a known technology using a feed block with two or more orifices arranged so that the resulting flow of the extrudate are combined and fused together in a stream with a multilayer flow, and continuing through the flow channel toward the annular spinneret . Multilayer flow passage can be, for example, substantially rectangular flat laminar flow that is generally flat, planar layers of approximately equal thickness and width, as described in patent documents WO 2008/008875; USP 3,565,985; USP 3,557,265; and USP 3,884,606, all of which are hereby incorporated herein by reference. Alternatively, two or more layers in a multilayer flow stream can be created encapsulation techniques, such as shown in FIG. 2 and 5 of the patent document USP 4,842,791, with the encapsulation of one or more essentially annular or rectangular encapsulating layers laminated onto a core, or as shown in FIG. 8 of the patent document USP 6,685,872, mainly in the annular inhomogeneous encapsulating layer. As you can imagine, the encapsulating layer allows the formation of two outer layers of the multilayer on the flow passage when the fluid flow is formed and out of the ring-shaped die. Patent documents USP 4,842,791 and USP 6,685,872 are hereby incorporated herein by reference.
In the present invention the coextrusion process to create multilayer flow passage includes stages in which are combined simultaneously or successively at least a first stream of molten thermoplastic polymer material and at least a second stream of molten thermoplastic polymer material, and optionally additional threads. Synchronous layering layers may be added or combined in one and the same point of fluid flow. Simultaneous lamination can be performed, for example, if the rheology of resinous materials are similar. The feeding unit for sequentially layering additional layers are added at different points along the fluid flow. For example, the multilayer flow flows can be created synchronous combined streams in processes using a feed block as described in patent documents USP 3,565,985; USP 3,557,265; and USP 3,884,606. As indicated in patent documents USP 3,557,265 and USP 3,884,606, with their flow over the multilayer also referred to as "interdigitated" or "interleaved."
Form sequential addition streams shown in patent documents USP 4,842,791 and USP 6,685,872, both of which are hereby incorporated herein by reference, wherein the multilayer streams creating encapsulation original stream.
In one embodiment, as shown in FIG. 1, materials 1 and single screw extruders is fed to spinneret 5 bilayer A / B of the supply unit 6, having at least two openings. In another embodiment, as shown in FIG. 2, materials from single-screw extruders 1 and 2 are fed to a spinneret bilayer A / supply unit 4, having at least two openings.
Optional multiplexing layers
Optionally, after the process of co-extrusion feed block, or when the feed stream to produce a multilayer flow by other means, with a multilayered flow passage can then be processed in additional processing steps replicating layers that are generally known in the art. For example, see Patent Documents USP 5,094,788 and USP 5,094,793, hereby incorporated herein by reference, which are forming the flow multilayer passage split flow multilayer flow comprising a thermoplastic resinous materials, at first, second and, optionally, other substreams, and combining multiple streams layering them on top of each other and compression, thereby forming a multi-layer flow over. Multiple layered on each other substreams are welded together in adjacent and generally parallel relationship relative to each other in a multilayer flow stream. Inside the multilayered flow passage numerous substreams exhibit uniformity, continuity and thickness, specifically designed to create the desired shape having the desired properties. The process of replicating the layers can provide a multi-layer flows over that contain many layers, such as a few hundred layers.
For multilayer flow flows used in the present invention, depending on such factors as desired properties, the manufacturing cost, end use, etc., the streams contain at least 4 layers, preferably more than about 4 layers, preferably more than about 5 layers, preferably more than about 8 layers, preferably more than about 10 layers, preferably more than about 11 layers, more preferably greater than about 20, more preferably greater than about 25, more preferably greater than about 27 layers, more preferably greater than about 30 layers, or more than about 40 layers, or more than about 50 layers, or more than about 60 layers, or more than about 70 layers, or more than about 75 layers, or more than about 80 layers, or more than about 90 layers. Furthermore, although the number of layers in the flow can be essentially unrestricted, flows can be optimized for the contents to about 10,000 layers inclusive, preferably up to about 1000 layers, inclusive, more preferably up to about 500 layers, inclusive, or up to about 400 layers, inclusive, or to about 300 layers, inclusive, or up to about 250 layers, inclusive, or up to about 200 layers, inclusive, or up to about 175 layers, inclusive, or up to about 150 layers, inclusive, or up to about 125 layers, inclusive, or up to about 100 layers, inclusive. As is known in the art, multi-layer structure comprising a plurality of layers as shown in one or more of the methods discussed above, often referred to as "microlayered" structure.
In one embodiment, as shown in FIG. 1, material exiting the feed block die 6 is fed into a series of optional multiples 7 layers. In another embodiment, as shown in FIG. 2, materials exiting from the spinneret the feeding unit 4 is fed to a series of optional multiples of 5 layers.
Optional encapsulation
Optionally, if encapsulation has not yet been used for generating at least two of the layers in the flow multilayer flow, it can then be applied by known methods as mentioned above to create surface layers that protect the internal layered structure, such as very thin layers that create a micro-structure. For example, see patent document USP 5,269,995, which is hereby incorporated herein by reference. For example, the present invention can be used in encapsulating the die, as shown in FIG. 4 and as described with reference to FIG. 4, 5, 7 and 8, shown in the patent document USP 6,685,872, hereby incorporated herein by reference. Encapsulation in a relatively uniform encapsulating layer may also be carried out according to the instructions of the patent document US 4,842,791, incorporated herein by reference. As described in the patent document USP 6,685,872, can be used uneven encapsulating layer, particularly if it is necessary to create the desired area of overlap, the modified cross-head with an annular die shown in its type. As it states, the non-uniform slot die can create appropriate thickness variations in the encapsulating layer. For example, in one embodiment, can be encapsulated entire periphery or circumference of the multilayered flow passage. For example, it can be completely encapsulated with the ends of the flow passage of the multilayer. If, for example, multilayer flow passage comprises two layers and then subjected to encapsulation, the cross section of the encapsulated multilayered flow passage shows four layers.
Encapsulating (boiling) layer (s) (s) may advantageously improve the stability of flow of multilayer flow as it flows through encapsulating the die, annular die, and in all subsequent operations, such as those shown with encapsulating the die described in Patent document USP 6,685,872. Encapsulating (boiling) layer (s) and (s) may have a functional purpose, for example, to increase resistance to weathering, stability against UV radiation, etc. In an alternative embodiment, the action of an optional encapsulating layer may alternatively be provided for less than the full circumferential surface or peripheral flow multilayer flow, including the use of protective surface layers or several layers from the supply unit, in addition to the number required for producing base, the desired properties of the annular structure. For example, encapsulating (ing) layer (s) (s) may be an expendable layers, which can then be removed or damaged. As shown in FIG. 1, at least one encapsulating layer is applied to the flow passage multilayer extruder with optional 3 optional encapsulating the die 8. As shown in FIG. 2, optional encapsulating layer is introduced in the flow of the multilayer over the extruder using an optional 3 optional encapsulating the die 6.
Alternatively, if desired, it is encapsulated in only a part of the circumferential surface of the multilayered flow passage. For example, they can be coated with the upper and lower portion of the stream while leaving open sides.
Optional flow channel
Optionally, in some alternative embodiments, after forming a generally rectangular or other noncircular multilayer flow stream having a relatively long distance movement (for example, greater than about 5-10 times the diameter of the thread), or it is necessary to change the direction of flow (e.g. from horizontal to vertical extrusion process steps in the blow molding). In such cases, it may be provided round tubular flow channel for receipt of the encapsulated multilayered flow passage. A non-circular cross-sectional shape of the fluid flow smoothly into circular shape which, when retained in the fluid stream will minimize violation of the layers, which may be caused by secondary flows formed by the elastic forces in the multilayer flow stream. When used, the round tubular flow channel may be formed in an arc with a relatively large radius of curvature compared with the diameter of the pipe to change the direction of flow of the multilayer-over, for example, from horizontal to vertical. The flow direction at the outlet end of the round tubular flow channel may be oriented at an angle up to 90 degrees or more with respect to the direction of flow into the round tubular flow channel. To change the direction of flow with a round tubular flow channel about 90 degrees ratio of the radius of curvature of the round tubular flow channel (providing a change of direction of flow) to the inner diameter of the round tubular flow passage is preferably greater than 1 to 1, preferably greater than 2 to 1, more preferably greater than 3 to 1 and more preferably greater than 5 to 1. The flow multilayer flow should be maintained in the circular tube cross-section, until it reaches the flow-distributing channel manifold annular die, at which point the flow passage multilayer can move smoothly from circular geometrical shape to the geometric form for proper flow distribution channel-manifold annular die.
FIG. 3 shows a sample flow passage of circular multilayer tubular flow channel having a relatively large radius of curvature of the pipe diameter. The radius of curvature of the round tubular flow channel was 3.4, the inner diameter of the circular tubular flow channel was 1.0, and the ratio of the two values was 3.4. The flow of the multilayer included over 27 alternating layers of polystyrene, painted in black and white for contrast. This was done using two extruders having a diameter of 1.25 inches (31.75 mm) operating at a temperature of 420 ° F (215,6 ° C) and with a capacity of 12 lbs / hr (5.44 kg / hour). Technology and equipment details described below in the section "Methodology". Extruders have been stopped, and the flow of the multilayer over left to cool and solidify in the round tubular flow channel. Next round tubular flow channel is removed, leaving the hardened laminate. The flow direction was towards the position indicated by reference numeral 4 on the lower right side.
The cross-section was photographed at position 4, as shown in FIG. 4 (which is shown after the transition from a circular geometrical shape round the tubular flow channel in a square shape).
FIG. 4 shows that the fibers remain unbroken when they are flowed along the curve toward the position indicated by reference numeral 4.
FIG. 5 shows part of a cross-head die 100. The cross-head die flow direction must be changed from the horizontal to the vertical plane of the extrusion die. Feed multilayer flow flows into the die through the pipe 105. It enters the die 100 through a circular tubular flow channel 110 having a relatively large radius of curvature compared with the diameter of the pipe. The flow turns 90 ° from the horizontal path at the inlet to the directed vertically upwards. The flow enters the channel 115, around the die leading to the overlapping region on the opposite side. Material flows upwardly from the channel 115 through passageway 120 and out the die. One skilled in the art will appreciate that the flow in the die could be oriented up or down, depending on the particular type of die.
FIG. 6 shows a part cross-head die 200, in which the radius of curvature is small. The fluid flow enters the nozzle of the tube 205. The round tubular flow passage 210 has a small radius of curvature relative to the pipe diameter, for example less than 1 to 1). The flow direction rotates by 90 ° from the horizontal to the vertical path. The flow enters the channel 215 around the die and upward from the channel 215 through the channel 220 and out the die.
Round tubular flow channel may be within the die, as shown in FIG. 5, or outside the die. If it is located outside the die, a tubular flow channel changes flow direction from horizontal to vertical prior to entering the die, and during the die is vertical to the channels around the die.
Therefore, as described above, the multilayer flow passage may be constructed from a variety of sources, or stages, including one or more of: the supply unit, optionally (ones) multiplier (s) layers, optionally encapsulating the die or non circular tubular flow channel.
Process using an annular die
Feed flow creates a multilayer annular die to feed or to supply a single-channel distribution manifold annular die to form a multilayer annular flow passage at the time when it exits the annular die. Collector-distributor duct distributes the flow from the passage to form a multilayer annular shape, at the same time preserving the continuity of the layers in the multilayer flow stream. A single-channel distribution manifold may create, for example, an array of flow to a cylindrical shape, mass flow with the tapered cylindrical shape or a planar array to form a flow, all fed annular die and out of it.
By the annular die can be supplied by more than one thread to a multi-layer flow, but each thread is the multilayer over has its own distribution channel collector. For example, FIG. 1 an extruder 2 (or extruder 4, or both) may be replaced by the arrangement of one or more extruders feeding units, multipliers layers and encapsulating the dies to produce a second (or third) flow multilayer flow flowing into the distribution channel, the collector 11 ( or collector-distributor duct 9).
It should be noted that in a typical industrial application, the term "core" often means or includes "distribution channel-collector" is used somewhat interchangeably with the term. As used herein with respect to the annular spinneret, a distribution conduit-reservoir is the space of the flow or the area of the flow channel, which receives and transmits a stream of fluid through and around the surface of the core block in the base with a cylindrical, planar or tapered shape than creates an annular flow profile of the fluid environment that goes annular. It is often created and disposed between the center core block and the upper or outer shell or plate stack. Channel manifold distributes flow of the molten polymer around the core and forms an annular shape of the flow to exit from the spinneret.
For example, if the channel-collector has a planar configuration, it is located between two horizontally oriented plate stacks and leads to a vertically oriented annular spinneret. In this situation the collector channel is oriented in a direction generally parallel and coplanar to the direction of flow and the interfaces between layers in a multilayered flow passage. Advantageously, the planar channel-manifold distributes and generates flux with a multilayered passage to form an annular shape to exit from the spinneret.
In one embodiment, a single distribution channel, the manifold may have a geometrical shape crosshead type. The distribution channel-collector having a geometric shape cross-head type, as shown for example in FIG. 9 of the patent document USP 6,685,872, the incoming fluid flow of the molten resin separated at the channel inlet-manifold or in the vicinity of two fluid stream which travel mainly in opposite circumferential directions around the core, and also creates a very thin stream of fluid which flows towards the exit of the die along the core in the axial direction. Divided flows of the fluid from the molten resin and then continue to move around the core in opposite directions to meet or merge streams on opposite hundred Rhone or near the core and form substantially annular fluid flow, which moves towards the exit of the annular spinneret. In some annular die cross-head, depending on the design and / or choice of material, can be noticeable in the weld location associations or junction, where the two flow. This may be undesirable in some applications and, perhaps, would be advantageous to use other embodiments.
In an alternative embodiment, a single distribution channel-manifold geometric shape has a modified cross-head. The modified geometric shape of the distribution channel crosshead type collector described and shown in FIG. 9, 10, 11 and 12 of the patent document USP 6,685,872, incorporated herein by reference. This collector-distributor duct having a modified geometric shape crosshead type comprising a housing and a pair of main channels, the length of the distribution channel from the inlet of the collector body around the core in opposite directions. Opposite ends of the main channels are overlapped with each other and greatly reduces the impact and visibility of the weld.
In a preferred embodiment, the modified cross-head die an annular flow passage multilayer may be divided into at least two separate streams of fluid, wherein each individual fluid flow travels in opposite directions in the pair of main channels around a circumferential surface of the body the distribution channel is the collector. In another preferred embodiment, the individual fluid streams overlap each other, but remain separated in the distribution channel to the reservoir, where the opposite ends of the main channels are overlapped with each other. The magnitude of overlap is preferably optimized for a multi-layer structure to create the desired properties of the product in the region of overlap.
As used herein, the terminology "desired properties of the product in the overlapping region" refers to several possible effects that may be caused by a modified cross-head die. For example, the overlapping portions of the collector channel may be arranged so as to create a substantially constant properties over the entire circumference of the annular structure extends from the non-overlapping area in the overlapping region and through it. For example, USP 6,685,872 patent document discloses a persistence barrier properties using this method. Alternatively, since the area of overlap will have twice the number of layers in half of the average thickness of the layers, it may occur intentionally marked shift in terms of physical or optical properties. It is possible that there is a substantial transition to the annular structure be used advantageously in several ways. For example, it could be applied to assure uniform orientation or placement of the ring-shaped products. This could create a simple way to localize the overlap to remove if it is harmful to the balance of the circumferential surface of the product.
When using a spinneret plate ("pancake" spinneret) overlap can be formed by providing one end above the other so that the two ends are at different heights (more so than at various radial distances as a modified cross-head die).
Overlapping can be formed in various ways, including but not limited to, stepped transition or flat sloped transition, as shown in FIG. 7A-B. Surprisingly, it was found that the layers in the overlap region remain undisturbed, being formed with a stepped transition or gentle slope transition.
This is illustrated in FIG. 8A-B and 9A-B. FIG. 8A-B are obtained using an atomic force microscope (AFM) image of microlayers in blown film. The film had 27 alternating microlayers of low density polyethylene and AffinityTM polyolefin plastomer material in the core. The film was made using an extruder with a size of 1.25 inch (31.75 mm) and 1.75 inches (44.45 mm) operating at a ratio of layers 50% / 50%. Production Rate of the core was about 12 lbs / hr (5.44 kg / hr) total line capacity of about 60 lb / hr (27.22 kg / hr). Details of the method and equipment described below under "Method". FIG. 8A shows the presence of intact microlayers in blown film outside the region of overlap. FIG. 8B shows the area of overlap of the film of Fig. 8A, which has twice as many layers as the same total film thickness, and the layers remain undisturbed.
FIG. 9 is obtained using transmission electron microscopy (TEM) image of microlayers in the overlapping region of blown film. Each of sections A and B 100 comprises alternating microlayers of low density polyethylene and AffinityTM polyolefin plastomer material in the core. The film was manufactured by using an extruder with a size of 1.25 inch (31.75 mm) and 1.75 inches (44.45 mm) operating at a ratio of layers 50% / 50%. Production Rate of the core was about 12 lbs / hr (5.44 kg / hr) total line capacity of about 60 lb / hr (27.22 kg / hr). Details of the method and equipment described below under "Method". The layers are not damaged.
Note that the barrier layers in the structures disclosed in Patent document USP 6,685,872, are thicker than described herein microlayers. Handle multiple thicker layers and store them undisturbed lighter than many thinner layers. In addition, it is easier to manipulate the layers in the die for blow molding, which is less than the typical blow molding die.
As shown in FIG. 1, optionally encapsulated multilayer flow stream is fed into the distribution channel-manifold annular die 10. Optionally, additional fluid streams can be produced by two extruders 2 and 4 may be used to encapsulate the multilayer flow passage with additional distribution channel 9 and the reservoir 11 inside the annular spinneret. Each of the additional fluid flow may be a flow with a monolayer or multilayer flow including flows multilayer flow, which are the same as the primary encapsulated multilayered flow stream with or different from it. Each of the distribution channel 9 and the reservoir 11 may be a conventional channel-reservoir, or may have the same geometric shape modified distribution channel collector 10 crosshead type.
Then multilayer annular flow passage comes out, i.e. it removed from the annular spinneret to form an annular multi-layered structure.
Overlapping separated fluid streams form a flow of fluid, wherein the ends of the fluid flow is not open to the surface of the resultant structure. In one embodiment, the encapsulation and flow multilayer overlap can be eliminated over the appearance of the layered end surface of the annular obtained multilayer structure, and eliminates the traditional weld. Exception layered ends and / or weld advantageously improves both the mechanical and physical properties of the annular multi-layered structure. In at least one embodiment, the removal of the ends of laminated annular favorably improves the properties of the multilayer structure by storing at least permanence or improved properties in the region of overlap compared with the properties of the rest of the perimeter of the annular article.
Methods for producing blown film and / or blow molding
After exiting the annular spinneret annular multilayer structure can be stretched by being in the molten state or semi-solid, for monoaxial, biaxial or multiaxial orientation structure. For example, a multiaxial orientation may be relevant in the form of inflation, creating a radial orientation, the axial orientation and different thicknesses. Furthermore, for example, monoaxial orientation can be used to form coatings on wires and cables, tubes, pipes, etc. In embodiments where the applied foamed thermoplastic resinous material is achieved by pulling the macroscopic orientation of cells cell foam material within the expanded thermoplastic polymer material. The cells of the foam may have a different degree of orientation of the macro.
Examples of stretching include, but are not limited to, (i) a monoaxially hood between the annular die and the suction roll, (ii) a three-dimensional blow molding, or in the case of blowing a bubble of blown film from the exposed surface, either inflating the sleeve in the mold (blow molding), and (iii) draw the profile by the caliber and / or quench tank. Typical draw ratio, based on a monoaxial stretching process, range from about 2: 1 to about 50: 1, preferably from about 5: 1 to about 30: 1. "Factors monoaxial stretching" represent the ratio of the drawing speed to the velocity with which the annular structure emerges from the spinneret. The coefficients for the blowing process of biaxial stretching, can vary from about 1.5: 1 to 20: 1, preferably from about 2: 1 to 5: 1. Blowing coefficient is the ratio of the diameter of the annular end product or article to the diameter of the product exiting the annular spinneret. Then, an annular multi-layer structure is stabilized by chilling or stimulated (e.g., air cooling, quenching, etc.), or spontaneous, i.e. to achieve equilibrium with the ambient room temperature. As shown in FIG. 1, in one embodiment, may be formed bubble 12 of blown film. As shown in FIG. 2, upon receipt of the product by blow molding the annular multi-layered structure in the form of a sleeve can be placed into a mold for blow molding, and prior to the acquisition inflated shape of the mold to form an annulus as a blow molded product. Exemplary articles obtained blow molding can be fabricated using a typical head 7 for blow molding and the cavity 8. blow ratios when blow molded articles and blow molding processes can vary from about 2: 1 to 10: 1, preferably from about 3: 1 to 5: 1.
Optionally, the process may be performed reheating annular multi-layered structure. The structure is reheated to a temperature below the melting point of the high melting polymer structure. Then the structure is subjected to monoaxial or biaxial stretching in the semi-solid structure for orienting and then cooled. The cooled structure can be used, for example, shrink films.
The resulting ring-shaped multi-layer structure
The annular multi-layer structure according to the present invention, depending on such factors as desired properties, the manufacturing cost, end use, etc., may comprise, for example, at least about four layers, preferably more than about 4 layers, preferably more than about 5 layers, preferably more than about 8 layers, preferably more than about 10 layers, preferably more than about 11 layers, more preferably greater than about 20, more preferably greater than about 25, more preferably greater than about 27 layers, more preferably greater than about 30 layers, or more than about 40 layers, or more than about 50 layers, or more than about 60 layers, or more than about 70 layers, or more than about 75 layers, or more than about 80 layers, or more than about 90 layers. It should be understood that in certain embodiments, in the areas of overlap in the structure, the number of layers may be twice as high as in other regions of the structure. Furthermore, although the number of layers is theoretically almost unlimited, flows can be optimized for the contents to about 10,000 layers inclusive, preferably up to about 1000 layers, inclusive, more preferably up to about 500 layers, inclusive, or up to about 400 layers, inclusive, or up to about 300 inclusive layer or layers to about 250, inclusive, or up to about 200 layers, inclusive, or up to about 175 layers, inclusive, or up to about 150 layers, inclusive, or up to about 125 layers, inclusive, or up to about 100 layers, inclusive. As is known in the art, multi-layer structure comprising a plurality of layers as shown in one or more of the methods discussed above, often referred to as "microlayered" structure.
In one embodiment, the annular multilayer product obtained are substantially uniform thickness and include overlapping and non-overlapping peripheral areas; wherein the laminated structure in non-overlapping area in the overlapping region is doubled. As mentioned above, in certain embodiments, where the overlap area is created using the modified cross-head die, in the structure, the number of overlapping layers can be twice larger than in other regions of the structure.
As used herein, the term "substantially uniform thickness" in relation to the annular perimeter relates mainly to the fact that in the embodiment where the annular laminated products have overlapping domain thickness overlapping region can be generally assumed component and typically is at substantially the same as the thickness of the non-overlapping area. Of course, this is a matter of small, random and unintentional thickness variations. Therefore, the overall thickness uniformity means that the variation in thickness of the structure along the annular perimeter in particular between any overlapping and non-overlapping areas, if any, is preferably less than 10%, preferably less than 5%, more preferably less than 2%, most preferably less than 1% . In other embodiments, the spinneret may purposely create some unevenness in thickness of the perimeter of the annular structure.
As is apparent from the general description of the invention here and elsewhere, the present invention provides numerous advantages annular layers and in particular the annular microlayers annular structures in which the advantage of multiple layers shown and is supported around the perimeter of the annular article. As discussed above, in situations where they create a region of overlap may be areas where the layers themselves are not completely continuous around the ring, but instead there is a sufficient and / or excessive overlapping layers to compensate for thinning of the layers and the end points in the overlapping region .
For example, the overlapping region may be arranged so as to provide substantially constant characteristics over the entire circumference around the annular structure, passing from the non-overlapping area in the overlapping region and through it.
As known in the art for producing a multilayer of micro systems and average layer thickness is a function of the final thickness of the micro / or multilayer structure microlayered / laminated component in the structure and number of layers produced in the thickness, and can be calculated from them. Preferred thickness for of micro / or multilayer structures for use as a component in the structure can vary for any particular use, and will be further discussed below. The annular multi-layered structure may be formed in a layered organization in a wide variety of repeating structural fragments in a layer or repetitive configurations, such as repeating units A / A, A / B, A / B / A, A / B / C, A / B / C / B / A, etc., by the proper selection and use of multilayer flow supplied and methods replicating layers according to various aspects and embodiment of the present invention. The thickness of the structure can vary depending on various factors such as the thermoplastic resinous materials used, whether expanded or unexpanded materials desirable properties of the structure, etc. Furthermore, it should be noted that, depending on whether it will be subsequently combined with additional layers of a multilayer annular die, a multi / microlayer structure may form the whole film structure, or part of it. In optional alternative embodiments, the annular laminated structure according to the present invention are actually a component of the base structure and additional layers are combined with one or more additional channels reservoir spinneret.
In one embodiment of the present invention wherein the embodiment is provided use of a multilayer annular structure using it as a whole the non-foamed film or portion thereof, preferably an annular blown film structure, the structure would have a thickness of at least about 7 micrometers (0.3 mils), preferably by at least about 10 micrometers (0.4 mils), more preferably at least about 15 micrometers (0.6 mils). For applications of the film thickness of the film is typically less than about 380 micrometers (15 mils), more preferably less than about 250 micrometers (10 mils) and more preferably less than about 125 micrometers (5 mils).
Use of the structures for other types of articles such as sleeves for blow molding, extruded annular profiled product such as a pipe, particularly where there may be used expanded layer may require a thickness of at least about 1 millimeter (mm), preferably at least about 1.6 mm, and the pipe up to a thickness of about 152 millimeters (6 inches), preferably up to about 90 mm (3.5 inches) inclusive. For products themselves obtained blow molding, the wall thickness would be varied in the range from about 1 mm to about 13 mm.
Optionally present outer "shell" being either created at a surface (children) of the annular multi-layer structure (with the use of additional channels reservoir annular die), or included in the annular multilayer structure as described above. For example, it may have one or more annular coextruded coating layers are added to one or both opposing sides of the annular multi-layer structure, or multiple redundant outer covering layers included in the latter. If there is (are) outside (ones) coating (ones) layer (s) (s) may be greater than zero amount and up to about 90% of the thickness of the final resultant structure, or to about 80% of the thickness, or to about 70 % of the thickness, or to about 60% of the thickness, or to about 50% of the thickness, or to about 45 percent, or up to about 40 percent, or up to about 30% thickness, based on the total thickness of the structure. As used, the outer shell is generally in the range would be at least about 1% of the thickness, or at least about 5% of the thickness, or at least about 10%, or at least about 20%, or at least about 30 percent, or at least about 40%, or at least about 45%, or at least about 50 percent, or at least about 60%, or at least about 70%, or at least about 75 percent, or at least about 80% of the thickness.
Materials for the polymer layer (and optional foam layers)
The layers in the multilayer structure may be formed of the same material or of two or more different materials.
Any thermoplastic resinous material that can form a fluid stream of a thermoplastic polymer and form a film, may be used as the fluid stream in the method according to the present invention and as a layer in the product according to the present invention. His choice will be determined by the intended use for the product, and any adhesive and / or technological requirements for the selection of the other layers or fluid flow. Preferred thermoplastic resinous materials include thermoplastic polymers. As used herein, "polymer" means a polymeric compound prepared by polymerizing monomers, whether of the same or different types. The generic term "polymer" embraces the terms "homopolymer," "copolymer" and "terpolymer" as well as "interpolymer."
"Interpolymer" means a polymer prepared by polymerizing monomers of at least two different types. The generic term "interpolymer" includes the term "copolymer" (which is usually used to refer to a polymer prepared from two different monomers) as well as the term "terpolymer" (which is usually employed to refer to polymers prepared from three different types of monomers).
For example, can be used and extremely suitable for practical implementation of the invention, the thermoplastic polyolefin polymers, also referred to as polyolefins. "Polyolefin polymer" means a thermoplastic polymer which is derived from one or more olefins. The polyolefin polymer can bear one or more substituents, for example, a functional group such as a carbonyl, sulfide, etc. For purposes of this invention, "olefins" include aliphatic and alicyclic compounds having one or more double bonds. Exemplary olefins include ethylene, propylene, 1-butene, 1-hexene, 1-octene, 4-methyl-1-pentene, butadiene, cyclohexene, dicyclopentadiene, and the like. These include, but are not limited to, polyethylene (PE), polypropylene (PP) and polybutylene (PB), and polyvinyl chloride (PVC, both rigid and flexible). Specific examples of useful olefin polymers include ultra low density polyethylene (ULDPE, for example, ethylene / 1-octene polyethylene ATTANETM, manufactured by The Dow Chemical Company ("Dow"), with a typical density between about 0.900 and 0.915 and a typical melt index (I2) between about 0.5 and 10), linear low density polyethylene (LLDPE, for example, ethylene / 1-octene DOWLEXTM polyethylene, manufactured by Dow, with a typical density between about 0.915 and 0.940 and the typical value I2 between about 0.5 and 30), homogeneously branched linear ethylene / alpha-olefin copolymers (e.g., polymers TAFMER® from the company Mitsui Chemicals America, Inc. and EXACTTM resins from the company ExxonMobil Chemical (ExxonMobil)), homogeneously branched, mainly linear ethylene / alpha-olefin copolymers (e.g. polymers AFFINITYTM and ENGAGETM, produced by Dow and described in patents USP 5,272,236, 5,278,272 and 5,380,810), catalytic linear statistical olefin copolymers (e.g., polyethylene / olefinic block copolymers INFUSETM, in particular polyethylene / alpha-olefin block copolymers, and especially polyethylene / 1-octene block copolymers, manufactured by Dow and described in patent documents WO 2005/090425, 2005/090426 and 2005/090427), and ethylene copolymers obtained by free-radical polymerization under high pressure, such as ethylene / vinyl acetate (EVA) and ethylene / acrylate and ethylene / methacrylate copolymers (e.g., polymers and ELVAX® ELVALOY®, respectively, from the company EI Du Pont de Nemours & Co. (Du Pont), copolymers of ethylene with acrylic acid and ethylene-methacrylic acid (e.g., polymers PRIMACORTM from Dow EAA and EMAA NUCREL polymers from the company Du Pont), various polypropylene resins (e.g., polypropylene resins and INSPIRE® VERSIFY®, produced by Dow, polypropylene resins VISTAMAXX®, manufactured by ExxonMobil, and random copolymer polypropylene ("RCP"), and polymers and copolymers of cycloolefins, or cyclic olefins ("COP's" and "COC's", respectively, wherein the COC's include, for example, polymers trademark Topas® from the company Topas Advanced Polymers, and COP's include, for example, polymers with the brand Zeonex® from the company Zeon Chemicals). COP's and COC's are known and are described for example in patent documents EP-A-0 407 870, EP- A-0 485 893, EP-A-0 503 422 and DE-A-40 36 264, incorporated herein by reference. As is known, and the COP resin used COC formulated with one or more cycloolefins, for example, such as norbornene.
In one alternative embodiment of the present invention, one or more layers in a multilayer flow stream, and annular multi-layered structure is a LLDPE. Preferred LLDPE-ethylene polymers are interpolymers of ethylene with at least one C3-C20-α-olefins, particularly preferred are LLDPE-ethylene and C3-C12-α-olefin. Examples of such comonomers include those of C3-C20-α-olefins such as propylene, isobutylene, 1-butene, 1-hexene, 1-pentene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene, 1-decene and the like. Preferred comonomers include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene and 1-octene, and particularly preferred is 1-octene.
Other suitable thermoplastic resinous materials include monovinylidene aromatic polymers are prepared from one or more monovinylidene aromatic monomers. Exemplary monovinylidene aromatic monomers include styrene, toluene, α-methylstyrene, and the like. Monovinylidene aromatic polymer can bear one or more substituents, such as a functional group such as a carbonyl, sulfide, etc. Examples of monovinylidene aromatic polymers suitable for use as one or more layers in a stream with a multilayered passage and an annular multi-layer structure according to the present invention include polystyrene, polystyrene-acrylonitrile copolymer (SAN), acrylonitrile-butadiene-styrene modified rubber (ABS) and grafted rubber high impact polystyrene (HIPS).
Other thermoplastic resinous materials suitable for use as one or more layers in a multilayer flow stream, and annular multi-layered structure according to the present invention include polyesters such as polyethylene terephthalate and polybutylene terephthalate; polycarbonate resins; polylactic acid; polyamides such as nylon resins, including nylon-6, nylon-66 and nylon MXD6; thermoplastic polyurethanes; ethyl cellulose; copolymer of vinyl chloride and vinylidene chloride (PVDC); ethylene vinyl alcohol (EVOH); methylacrylate copolymer and vinylidene chloride; polymethyl methacrylate; and the like.
The thermoplastic resinous materials for these layers are preferably selected so that the resulting annular multilayer structure exhibits properties which are optimal for a given application. In preferred embodiments, the materials are selected based on the properties desired in the final resultant structure. For example, if the desired shrink properties may be selected materials that provide proper shrinkage characteristics, such as fibers of polyolefin resins. If desired barrier properties, may be selected materials that provide adequate barrier properties, such as PVDC or EVOH. If desired adhesive properties, selected materials that exhibit adequate adhesive characteristics bonding between other layers, such as EVA or EAA (ethylene-acrylic acid). For example, polyethylene resins having different density may be used to optimize stiffness and toughness. The desired properties of the final product may influence the choice of materials for the multilayer structure. Materials can be selected so that the rheological characteristics of the materials used are complementary and interdependent.
In addition, if necessary, additives may be added. Typical additives generally incorporated in polymer compositions for various purposes include accelerators or catalysts, surfactants, flame retardants, agents for adjusting the porosity, antioxidants, colorants, pigments, fillers and the like. Such additives will generally administered in conventional amounts.
The thermoplastic resinous materials used in one or more layers of fluid flow in the flow passage with a multilayer process according to the present invention may optionally comprise a foaming agent capable of generating expanded composition. That is, multiple streams of thermoplastic resinous materials in multilayer flow passage may independently create either expanded or unexpanded composition. In an alternative embodiment of the present invention, at least one thread comprises a foaming agent to create the expanded composition. As is generally well known in the art, expanded compositions comprise a foaming agent, foaming agent or expanding agent. Moreover, the expanded thermoplastic resinous compositions may include one or more compositions that provide the desired functional characteristics such as gas barrier (e.g., oxygen gas, carbon dioxide, etc.) the composition (e.g., film composition of an ethylene-vinyl alcohol or polyvinyl chloride), the barrier composition in respect of liquids or moisture which essentially acts to prevent the transfer of liquid or water from one side of the layer on the other side of the layer, the chemical barrier composition which mainly acts to impede the penetration of chemicals or gas on one side of the layer to the other side of the layer structure for the absorption of oxygen and etc.
Annular multilayer structure comprising a foamed or foam layer can be rigid or flexible and inflatable and includes molded films, pipes, coating for wire, fibers and other shaped annular profile.
If desired, the multilayer structure may include recycled materials. For example, in blow molding applications, the edge trimming of the blow molding operation can be used as a layer in the entire structure as a whole. These trimming edge material include all polymers used in the multilayer structure. For complex parts recycling amount may be up to 50% of the entire structure. Recyclable material could be used as one of many layers in the micro-structure, and it could be disposed between the micro structure and any coating layer or it could be used as a coating layer. However, the use of recycled material as a coating layer may be less desirable due to the presence of various combinations of polymers, which may adversely affect the contents of the package when it is on the inner side, or interfere with the subsequent phases of the press, if it is on the outer side.
Materials for alternative embodiments, including meltblown polymeric layers
In alternative embodiments using meltblown polymeric layers for the layers according to the present invention can be applied to any thermoplastic resinous material, either filled or unfilled inorganic material which can be subjected to swelling or foaming. These include and are preferably thermoplastic resinous materials discussed above with respect to non-expanded layers, including in terms of their relative preference. In one embodiment of the present invention, one and the same polymer material may be used for each purpose, for example, polystyrene can be applied as a foamable resinous polymer composition, and as a film-forming resin composition nevspuchivaemaya in the same multi-layer film composite structure.
Essentially any known blowing, inflate or expanding agent can be administered at any one or many of the thermoplastic resinous materials prior to the coextrusion process. Inflate or expanding agents include, without limitation, the physical blowing agent comprising a gaseous material and volatile liquids, and chemical agents which decompose into gas and other by-products. Illustrative inflating or expanding agents include, without limitation, nitrogen, carbon dioxide, air, methyl chloride, ethyl chloride, pentane, isopentane, perfluoromethane, chlorotrifluoromethane, dichlorodifluoromethane, trichlorofluoromethane, perfluoroethane, 1-chloro-1,1-difluoroethane, chloropentafluoroethane, dichlorotetrafluoroethane, trichlorotrifluoroethane , perfluoropropane, hlorgeptaftorpropan, dichlorohexafluoropropane, perfluorobutane, hlornonaftorbutan, perfluorocyclobutane, azodicarbonamide, azodiisobutyronitrile, benzolsulfogidrazid, 4,4-oksibenzolsulfonilsemikarbazid, p-toluene sulphonyl semicarbazide, barium azodicarboxylate, N, N'-dimethyl-N, N'-dinitrozotereftalamid and trihydrazinotriazine.
Chemical inflating agents include sodium bicarbonate, ammonium carbonate and ammonium bicarbonate, citric acid or citrates, such as sodium citrate, sodium glutamate, phthalic anhydride, benzoic acid, benzoates such as aluminum benzoate, azodicarbonamide, and azaizobutironitril dinitropentametilen. Preferably the chemical swelling agent comprises a mixture of sodium bicarbonate and citric acid, including chemical blowing agent (CBA) with tradename Foamazol 72 which is a concentrate comprising a mixture of citric acid and sodium bicarbonate in the form of tablets, commercially available in the market by the company Bergen International.
Swelling reagent are generally used in quantities which may be needed to provide a desired degree of reduction of the density in the foam layer and in the final product. The term "density reduction" and the degree of density reduction means a percentage value decrease in the percentage density foam layer and / or the final product using a chemical and / or physical means of the blowing. For example, lowering the density of the starting polymer (solid sheet) with a density of 1 g / cm3 to 0.9 g / cm3 at 10% density reduction, to 0.85 g / cm3 at 15% density reduction, etc. For a successful combination of economic efficiency and product specifications layer of foamed thermoplastic polymer desirably has a density reduction of at least about 10 weight percent ("wt%") based on the density of the original thermoplastic polymer, preferably at least about 15% by weight, most preferably at least about 20% by weight. To preserve the operational characteristics of the final product, such as a thermoformed layer of foamed thermoplastic polymer desirably has a degree of reduction of density of no more than about 90 weight percent ("wt%") based on the density of the original thermoplastic polymer, preferably up to about 80% by weight, more preferably up to about 70% by weight, most preferably up to about 60% by weight. In an alternative embodiment, the ranges and levels of density reduction can be achieved in the final multilayer structure by achieving good but to a certain extent greater density reduction in the expanded layer, as is required for the final resulting structure, and the desired density reduction.
The weight amount of active chemical the blowing agent in the foamable composition is administered to provide a desired level of density reduction depends on the effectiveness and efficiency of the blowing agent specific, but it mainly was added in amounts of at least about 0,016, preferably at least about 0.02, and more preferably at least about 0.16 weight percent, based on the total weight of the active ingredient of the blowing agent of the chemical, and amounts up to about 0.8, preferably 0.4, and more preferably 0.36 weight percent, based on the total weight of the active chemical ingredient the blowing agent and the foamable polymeric composition.
Regarding the use of forming gas a liquid or another person the blowing agent in the foam extrusion process, the added amount of physical the blowing agent injected into the foamable composition depends on the desired level of density reduction and the efficiency and effectiveness of particular the blowing agent, but was found suitable for use amounts of at least about 0.0001, preferably at least about 0,001, more preferably at least about 0.01 and more preferably at least about 0.063 weight percent, based on the total weight of the blowing agent physical, and up to quantities of about 0.7 weight percent, preferably up to about 0.3, more preferably up to about 0.2, and most preferably about 0.128 weight percent, based on the total weight of the blowing agent physical.
Cell dimensions and orientation of cells for meltblown layers can be adjusted by known methods for curing within the desired or acceptable ranges as it should for the desired properties, and to reduce the density and thickness of meltblown layers. For example, see. Patent documents USP 5,215,691 and WO 2008/008875, which are of planar formation of multilayer structures with expanded layers, both incorporated herein by reference.
Bloat agent should be introduced into the stream of molten intumescent thermoplastic resinous material under pressure which is sufficient to inhibit foaming of the melt flow, while the flow is forced through a coextrusion die. This pressure should substantially be at least 500 psig (3,45 MPa gauge), and preferably at least 1000 psig (6.89 MPa gauge). Furthermore, choosing the appropriate process conditions to ensure that the blowing or expanding agent were sufficiently mixed and dissolved in an intumescent thermoplastic resin composition. For example, the melting point of the non-expanded thermoplastic material may be lower than the desired temperature for foaming the intumescent thermoplastic material as described in Patent document USP 5,215,691, incorporated herein by reference, for the creation of an intumescent and meltblown layers.
The thermoplastic resinous materials and swelling or blowing agents for these layers are preferably selected so that the resulting multilayer structures exhibit optimum properties for this application. In preferred embodiments, the thermoplastic resinous materials are selected based on the properties desired in the final resulting structure, as discussed above.
In these alternative embodiments, the annular multi-layered structure comprising a foamed layer and layers preferably arranged alternately expanded and unexpanded layers.
These foam layers comprising expanded thermoplastic resinous material is typically constructed with a thickness of at least about 10 micrometers, preferably at least about 50 micrometers, and more preferably at least about 75 micrometers. The thickness may be less than about 1000 micrometers, preferably less than about 500 micrometers and more preferably less than about 300 micrometers. In a preferred embodiment, the density of each foamed layer is in the range from about 0.03 to about 0.8, preferably from about 0.10 to about 0.5 grams per cubic centimeter (g / cm3), as can be measured according to standard ASTM D 3575-93 WB. In an alternative embodiment, the density of the annular multi-layered structure having a foamed layer may be in the range from about 0.05 to about 0.9, preferably in the range from about 0.15 to about 0.6 g / cm3.
The products obtained by the ring-shaped die, and the method of its application according to the present invention can be advantageously used in barrier packaging such as packaging of processed meat products. The currently used packaging materials for hot dogs, meat for breakfast and other processed meat products, typically have 7 to 11 layers. Suitable 7-layer blown film structure of this type (which can then be subjected to thermoforming to form the tape substrate) can be obtained with the thickness of the structure about four mils (101.6 microns), as follows:
Layer% mils (microns) Nylon-6120,5 (12,7) MAH-g-PE * 261,0 (25,4) Nylon-650,2 (5,1) EVOH (38 mole percent ethylene) 100.4 (10.2) Nylon-650,2 (5,1) MAH-g-PE * 80,3 (7,6) LLDPE341,3 (33,02) 100 ~ 4.0 (101.6) * Polyethylene grafted maleic anhydride.
As is known in the industry, reducing the ethylene content in mole percent EVOH typically increases barrier performance by toughness and thermoformable. Tape thickness formed for these structures may range from 100-150 micrometers (4 to 6 mils). Problems of reducing the size of these existing multilayer barrier structures include the loss of the barrier properties due to poor thermoformed and / or destruction of EVOH and focused on the harmonization of barrier properties with toughness, optical properties and economic performance of the film.
A method for producing micro-blown film according to the present invention provides greater flexibility in achieving a greater number of layers (in excess of 15 and preferably more than 27 layers) to optimize the structure to improve at least one of the critical characteristics or better balanced such key technological properties as toughness, and barrier properties of the thermoformed, and generally reduce the cost of the film or increase the efficiency of the film.
For example, the multilayer barrier structure is of reduced thickness is as follows:
Layer% mils (microns) Nylon-6130.4 (10.2) nylon svyazka230,7 (17.8) Nylon-6 / EVOH / nylon 6 (microlayer) 200.6 (15.2) nylon svyazka100,3 ( 7,6) LLDPE341, (25.4) 1003 (76.2)
Mention microlayer in the above structure, and subsequently relates to composite multilayer structures according to the present invention in which the structure comprises alternating layers disclosed (tyh) polymer (s) composed of more than 10 layers, more preferably more than 15 layers and most preferably more than 27 layers. These structures can also comprise micro-encapsulation composite structure as described herein.
Part of the microlayer film made of nylon 6 / EVOH / nylon 6, or alternating layers of nylon 6 and EVOH. This structure provides a desirable combination of barrier properties, toughness, and cost thermoformable film.
Alternatively, the core component of nylon / EVOH / nylon structure into the original film with a thickness of 4 mils (101.6 microns) may be replaced microlayer core component with same total amount of material in percent by volume, but with one change, consisting in increasing the total number of layers each component ultimately providing enhanced barrier properties / shelf life and toughness for use.
Another alternative embodiment of the micro-structure of the barrier is:
Layer% mils (microns) microlayer of PP / Versify130,4 (10,2) nylon svyazka230,7 (17.8) microlayer of nylon-6 / EVOH / nylon 6200.6 (15.2) nylon svyazka100,3 ( 7,6) LLDPE341,0 (25.4) 1003 (76.2) * VERSIFYTM represents ethylene-propylene elastomer or plastomer resin, produced by The Dow Chemical Company.
Ethylene copolymers grafted with maleic anhydride (MAN), can also be used as a bonding layer instead of EVOH with nylon-6 in structure. This structure could be obtained in the form of a film with a thickness of 3 or 4 mils (76.2 or 101.6 mm), depending on the desired toughness to optimize the balance of cost and processability. Microlayer of polypropylene (PP) and the polymer Versify improves formability and toughness compared to pure PP, allowing the replacement of more expensive nylon.
Products and method for producing a multilayer annular structures according to an alternative embodiment of the present invention can also be advantageously used for forming a film with improved barrier properties. It is known to use a barrier of nylon-MXD6 to improve the performance of alignment steps after fabrication such as stretching in a tenter frame process or using a double bladder. These high barrier properties are desirable in the manufacture of packaging retort (sterilized with the content) with a long shelf life, where foods are exposed to high humidity during the retort process. However, the additional step of orientation by stretching in a tenter frame significantly increases the costs. A method of producing annular microlayers of the present invention can produce very thin layers of MXD6, exiting the single channel of the collector, and can subsequently be further oriented during the blow molding of the film. This provides a cost-effective creation of barrier properties without the need to apply the tenter frame (orientation semi-solid) film. Mixtures of nylon 6 or PET (polyethylene terephthalate) with nylon-MXD6 can also be applied in such structures of micro providing oxygen barrier function of the final film.
In yet another alternative embodiment, the products obtained by the ring-shaped die, and the method of its application according to the present invention can be advantageously used in the film structures for packaging dry foodstuffs. Packaging dry foodstuffs such embodiments include applications such as cereals, crackers, cookies and other foods that are sensitive to moisture. These structures include barrier materials for preventing penetration of moisture, oxygen and / or preservation of taste and aroma. Typical multilayer packaging for moisture-sensitive applications comprises a layer of high density polyethylene (HDPE), which may be used with the barrier layers of nylon or EVOH, including tie layers and infusible fibers, to create the required barrier properties for this application. Although the thickness of the barrier layer (e.g., EVOH or nylon) can be increased to improve the barrier properties of such a solution it is generally economically unacceptable due to the cost of the barrier polymer or the tool machinability problems that occur when thicker structures.
Thus, in alternative embodiments, the present invention can be very advantageously used to create micro-barrier layer structure in annular multilayer structures, particularly in blown film, to achieve a greater number of thinner barrier layers, particularly above about 15, and preferably greater than about 27 layers to optimize the structure to improve at least one of the critical characteristics or obtain a better matching between key technological properties, which include, but are not limited to, toughness, barrier properties and optical properties are also potentially at a lower overall cost, if preference is given to reduce the size.
Typical film structures are described below:
SloyVesovyh protsentovGermetiziruyuschy material15HDPE85SloyVesovyh protsentovHDPE55Svyazuyuschy material10NAYLON10Svyazuyuschy material10Germetiziruyuschy material15
Micro-structures can be prepared according to alternative embodiments of the present invention for achieving this balance using microlayers of very HDPE-layer sealing layer, the sealing layer is typically made from many known polymers, including, but not limited to, LLDPE, PB (polybutylene) , EVA or propylene plastomers and elastomers. Without wishing to go into the theory, it is assumed that the formation of micro structures in very thin layers create a unique crystal morphology, which improves barrier properties (Science, volume 223, pp. 725-726 (2009)).
The proposed structure would be similar to those described above:
SloyVesovyh protsentovGermetiziruyuschy material15Mikrosloisty HDPE85SloyVesovyh protsentovHDPE55Mikrosloisty binder / nylon / tie material30Germetiziruyuschy material15
Alternatively toughness could be improved using a medium density polyethylene (MDPE) instead of HDPE in the above examples. Further, to create more, better barrier properties and the possibility of increasing the shelf life of dry foodstuffs, as the absorption of water tends to reduce palatability, Nylon micro-structure in the above could be replaced EVOH copolymer.
Another structure that can provide an improved combination of toughness and barrier properties comprises two of micro composite structure within the whole film structure.
SloyVesovyh protsentovMikrosloisty HDPE55Mikrosloisty binder / nylon / tie material30Germetiziruyuschy material15
Another alternative embodiment of the structure is obtained except bonding layers and an improved balance of the "cost / effectiveness":
SloyVesovyh protsentovMikrosloy HDPE / NAYLON85Germetiziruyuschy material15
At the moment when recycled multilayer film comprising a barrier layer such as EVOH, HDPE, Nylon or Nylon-MXD6, the resulting polymer blend is used merely as a vehicle, since it does not provide further improve the barrier characteristics of the structure. Recycled barrier film may be introduced into inflatable micro-laminate structure having a very thin layers to further enhance the barrier properties. This may result in a longer shelf life and improves economic performance by reducing the size of the barrier layer in a multilayer structure.
In yet another alternative embodiment, the multilayered products obtained by the ring-shaped die, and the method of its application according to the present invention can be advantageously used in for improving barrier properties using nanoclays. Researchers have tried to apply nanoclays or other inorganic fillers with polymers to improve the barrier properties against oxygen and moisture. However, these techniques are not cost-effective and consistent. Inflatable microlayer film using nanoclays or other inorganic fillers such as talc, in combination with a suitable (E) a thermoplastic (s), polymer (s) are capable of improving barrier properties against gases and transport the molecules to ensure a balance between toughness and barrier properties. This allows you to improve the storage of silage, sacks for transporting heavy loads (HDSS), blister ("bubble"), packaging and other applications requiring high resistance to transport gas molecules.
In yet another alternative embodiment, the multilayered products obtained by the ring-shaped die, and the method of its application according to the present invention can be advantageously used in the field of containers for transportation of heavy loads (HDSS). HDSS used for packaging items such as animal feed, cement, humus, fertilizer and granular polymers. Typically a multilayer structure based on a linear low density polyethylene (LLDPE) or medium density polyethylene (MDPE), and polypropylene. Typical structures include three-layer structure of LLDPE / PP / LLDPE (against 40/20/40) having a thickness of 3 to 5 mils (76,2-127 m). There remains a need to improve the balance of "rigidity / toughness" film. Micro-structure capable of providing the desired improvement of the balance of "hardness / toughness" and may further create the conditions for reducing the size.
EXAMPLE HDSS-barrier micro-structure with a reduced thickness, comprising a microlayered core layer to achieve the desired improvement of balance "rigidity / toughness" is as follows:
PolimerObemnyh LLDPE30Mikrosloy% LLDPE / PP40LLDPE30
Shrink film for cold snacks are typically made up of LDPE or mixtures of LDPE / LLDPE and layered structures. Target process parameters include good optical properties (low haze), high shrinkage and high shrinkage tension for taut impermeable packaging, high puncture resistance and a high modulus of elasticity. For example, a film with a thickness of about 2.25 mils (62 microns (micrometers)) was used for shrink packaging of the 24 bottles of water or carbonated beverages. A typical example of the structure is coextruded LLDPE / LDPE / LLDPE (in the ratio of 10/80/10 by volume, etc. otsentov). Skins of LLDPE added to improve toughness, whereas LDPE shrink tension and provide optical properties. However, achieving a balance of the aforementioned characteristics is difficult when using a single polymer or a multilayer structure.
In one alternative embodiment of LDPE microlayer core, for example, a number of layers 27 would provide improved toughness without deteriorating the optical properties and shrinkage tension. In yet another embodiment, it can be applied microlayer core of LDPE / LLDPE, having more than 27 layers. Alternatively it can be used microlayered (preferably more than 27 layers) of the core mixture LDPE / LLDPE.
In one alternative embodiment, the annular laminated structures and methods of making them can be employed in blown stretch films. It is known that stretch film is used for wrapping pallets marker, and either applied by machinery or manually wrapped around. Stretch film wrapping pallets is applied to heavy loads, typically using a wrapping machine equipped with tension rollers. These stretch films are typically applied in a spiral, HERZ-TS in the up and down after the stretching with the stretching ratio of 100-300%. The casing for manual wrapping is usually applied by hand, and the coefficient of expansion not exceeding 100%. Wrapped items are basically industrial products which are transported on pallets, that is, chemicals, plastics, boxes, household appliances, etc. Key technical characteristics for these types of stretch films are high elongation at rupture, puncture resistance and tear resistance at Elmendorf. While these mechanical characteristics may be used for measurements of process parameters of the instrument, the final evaluation of the effectiveness in terms of application may be carried out using laboratory scale apparatus for wrapping a stretch film, such as supplied by Highlight Industries. This method allows to determine the final value of tensile force for the stretching force for unwinding and conditions of holding and piercing shell on a pallet. The films typically have a thickness on the order of about 20 micrometers (0.8 mils). Further, the film typically has an adhesive layer to impart tackiness. Typically, the adhesive layer using a very low density polyethylene (VLDPE), EVA, LLDPE, mixtures of LLDPE / LDPE, polyisobutylene (PIB), polyolefin plastomers and elastomers, and mixtures thereof. In addition, stretching of the film may also have a cover layer of materials typical of the coating layer comprising MDPE, mixtures of LLDPE / LDPE, and propylene-based polymers, including random copolymers (RCP) and mixtures thereof. The typical structure of a three-layer blown stretch film (adhesive on one side) is:
Polypropylene RCP (outer layer) - 0.1 mil (2.54 mm)
LLDPE (core layer) - 0.6 mil (15.24 microns)
VLDPE (an adhesive layer) - 0.1 mil (2.54 mm)
According to alternative embodiments of the present invention otherwise similar annular, inflatable, adhesive on one side film structure for use as a stretchable casings have core layers of the microlayered LLDPE or micro-mixture of LLDPE A / LLDPE B, where LLDPE A and LLDPE B represent two different polymer LLDPE. In the structure described above can also be applied microlayered component of the core layer using more than two kinds of LLDPE. The above microlayered composite film structures provide a desired combination of toughness, stretchability and holding force, as compared with a typical multi-layer structure, and also can improve the economic performance of the film due to reduction in size. Alternatively, A mixture of LLDPE / LLDPE B could be replaced by various combinations of LLDPE, LDPE, HDPE, and propylene-based polymers and mixtures thereof.
In addition, in one alternative embodiment, a core layer of LLDPE in a typical three-layer stretch film with the properties of double-sided adhesive film could be replaced microlayer core component of LLDPE to generate the following structure:
A mixture of LLDPE / VLDPE (an adhesive layer) - 0.1 mil (2.54 mm)
Microlayer LLDPE (core layer) - 0.6 mil (15.24 microns)
A mixture of LLDPE / VLDPE (an adhesive layer) - 0.1 mil (2.54 mm)
The above microlayered composite film structures provide the desired combination of toughness and tensile holding force compared to nemikrosloistymi multilayer structure allowing improved economic performance by reducing the size of the film.
The present invention is illustrated in further detail by the following examples. Examples are intended for illustration purposes only and should not be construed as limiting the scope of the present invention.
EXAMPLE 1
Film having a thickness of about 50 microns and comprising alternating layer 31 of low density polyethylene was prepared using an annular die having a diameter of 178 mm on a production line for the blown film. This film was prepared with the creation of a flow passage of a multilayer, which is a package of 27 layers, and encapsulating this packet into another polyethylene layer, and then applying this structure to the central distribution conduit-reservoir tiered multilayer annular die. Flow structure with a multilayered passage is formed using commonly understood supply unit 51-mm extruder and a 19-mm extruder, for example, mainly Accordingly, the method using a feed block as described in patent document USP 3,557,265, followed by multiplication in stage using multiplier as shown in the patent document USP 5,094,793.
Then these layers are encapsulated into one layer of polyethylene, basically according to the method as shown in Patent document USP 6,685,872. Encapsulating the fluid flow has a substantially rectangular geometric cross-sectional shape, it is converted into a circular transitional flow using a circular flow of the tubular channel and is fed into conduit-reservoir planar annular spinneret having a modified cross-head geometric shape to create a coextruded multilayer annular structure having a region overlap. The multilayer structure of the distribution channel flows through the collector, which forms an annular multi-layer structure, and creating overlapping layers in the extruded annular structure as shown in patent document US 6,685,872. As also shown in the patent document US 6,685,872, two additional plastic sheath is applied using a separate distribution channels in a multi-collector annular spinneret. The annular flow passage multilayer exits the annular die in the form of annular multi-layered structure, and it is inflated with a blowing ratio of 2: 1. The bubble is flattened and cut into two film webs. Films were obtained with performance values of 14 to 32 kg / h. This process is depicted in FIG. 1.
EXAMPLE 2
Annular foam structure film-thickness of 500 micrometers, with a layer 31 comprising alternating layers of foam and film of low density polyethylene, prepared using a spinneret with the diameter of 178 mm on a production line for the blown film. This film was prepared with the creation of the flow passage in the form of a multilayer stack of 27 layers (13 intumescent layers 14 nevspuchivaemyh film layers) and encapsulating this packet into another polyethylene layer as described above for Example 1. Then, the encapsulated fluid flow is directed through a transfer line as described above for Example 1, to the annular spinneret having a modified cross-head geometric form, and extruded as described above for Example 1. The multilayer structure flows through a central distribution conduit-reservoir, forming an annular area of micro-laminate structure with overlapping layers and a polyethylene membranes deposited using separate distribution channels in a multi-collector annular spinneret. The annular flow passage multilayer exits the annular die, and is inflated with the blowing ratio of 2: 1. The bubble is flattened and cut into two film webs. The structures obtained in terms of productivity of 14 to 32 kg / h. The structure has a final density of about 0.5 g / cm3.
EXAMPLE 3
The multilayer polyethylene structure formed by blow molding, obtained by using a sleeve created on line coextrusion, which has two 19-mm single-screw extruder, which fed the two components through a gear pump to a feed block mainly respectively patent document US 3,557,265, and a series of multipliers layers similar in construction to those which are described in patent documents US 5,202,074 and 5,094,783. The feed multilayer flow ethylene polymer encapsulated substantially according to the method shown in Patent document USP 6,685,872, for a multi-layer feed stream and fed to an annular cross-head die having a diameter of 38 mm and combining edges divided by the fluid flow on the back side of the channel-collector (i.e. it is, without creating overlapping region in extruded annular structure). The overall performance of extrusion varies between about 9 kg / h to 18 kg / h. Then the extrudate is directed into an annular mold cavity for the cylindrical bottles of 350 ml, cooled and inflated to form a part. These structures are formed on the die with a diameter of 38 mm with the size of the gap between the jaws of the die 1.52 mm. Forming part complete in a cylindrical mold of 350 ml capacity under a pressure of 0.4 MPa blowing.
EXAMPLE 4
A multilayer structure formed by blow molding, with alternating layers of polyethylene foam and a film having a high degree macrocellular orientation, is prepared from a sleeve produced according to the method shown in Example 3, in which one of the extruders gives polyethylene component which contains 2 percent by weight of azodicarbonamide chemical as the blowing agent. The overall performance of extrusion varies between about 9 kg / h to 18 kg / h. Then the extrudate is directed into an annular mold cavity for the cylindrical bottles of 350 ml, blow inflated at a pressure of 0.4 MPa, and cooled to form a part. These structures are formed on the die with a diameter of 38 mm with the size of the gap between the jaws of the die 1.52 mm. The overall density of the bottle is approximately 0.5 g / cm3.
METHODS
Film having a thickness of about 100 micrometers and comprising 6 individual layers of LLDPE-shells and bonding layers, and 27 alternating layers of EVOH and tie layer prepared using an annular die having a diameter of 178 mm on a production line for the blown film. This film was prepared with the creation of a multilayer core flow passage, which is a package of 13 layers of EVOH and 14 bonding layers, encapsulating this packet into another bonding layer, and then applying this structure to the central distribution conduit-reservoir tiered multilayer annular die. Multilayer structure of the flow passage is formed in the traditional feeding unit supplying the extruder with a diameter of 44.45 mm and an extruder having a diameter of 38.1 mm, for example, in substantial accordance with the method using a feed block as shown in the patent document USP 3,557,265, is then multiplied in step c using a multiplier, as shown in the patent document USP 5,094,793.
Then these layers are encapsulated in another binder layer in substantial accordance with the method shown in Patent document USP 6,685,872. Encapsulated fluid flow has a substantially rectangular geometric cross-sectional shape, it is converted into a circular transitional flow using a circular flow of the tubular channel and is fed into conduit-reservoir planar annular spinneret having a modified cross-head geometric shape to create a coextruded multilayer annular structure having a region overlap. The multilayer structure of the distribution channel flows through the collector, which forms an annular multi-layer structure, and creating overlapping layers in the extruded annular structure as shown in patent document US 6,685,872. As also shown in the patent document US 6,685,872, two additional plastic sheath is applied using a separate distribution channels in a multi-collector annular spinneret. The annular flow passage multilayer exits the annular die in the form of annular multi-layered structure, and it is inflated with a blowing ratio of 1.7: 1. The bubble is flattened and cut into two film webs. Films were obtained at values of productivity of 55 kg / h. This process is depicted in FIG. 1.
Materials used in the following Examples are shown in Table 1.
Comparative Example 5
The following comparative structure was prepared using a conventional 7-layer die with a blowing ratio (BUR) 1.7, with a total line capacity of 120 lb / hr (54.43 kg / hr), and extrusion temperature are listed in Table 2.
PolimerSloy% throughout plenkeChislo sloevDOWLEX ™ 2247G LLDPE301BYNEL 386 110 150% Bynel 3861/50% Bynel 38602,51EVALCA H171B9115 50% Bynel 3861/50% Bynel 38602,51BYNEL 3861101DOWLEX ™ 2247G LLDPE201DOWLEX ™ 2247G LLDPE201DOWLEX ™ 2247G LLDPE161
This structure has a thickness of 3.68 mil (93.47 microns), with a permeability to oxygen at 23 ° C and relative humidity (RH) of 80% at 0.238 cm3 / 100 in2 / day / atm (3.69 cm3 / m2 · 24 h · atm), which is comparable with literature values for N171V (film of a copolymer of ethylene and vinyl alcohol) at a temperature of 23 ° C and 80% RH.
EXAMPLE 5
The following example was prepared according to the invention on the equipment as described in Comparative Example 5. It uses the same material N171V as in Comparative Example but N171V microlayers operate as a binder for the core layer of 27 layers. The extrusion conditions are comparable to the control and are listed in Table 2. The structure is as follows:
PolimerSloy% throughout plenkeChislo sloev58% DOWLEX ™ 2045.11G / 42% ELITE ™ 5230GELITE 523 030 158% DOWLEX ™ 2045.11G / 42% ELITE ™ 5230G101Lotryl EMA 29MA032,515% EVALCA H171B microlayers transformed into a mixture of 10% (50% bynel 3861 / 50% admer nf498Anf498A) 1527Lotryl EMA 29MA032,5158% DOWLEX ™ 2045.11G / 42% ELITE ™ 5230G ELITE 523 020 158% DOWLEX ™ 2045.11G / 42% ELITE ™ 5230G ELITE 5230201
This structure has N171V and bonding layer BYNEL / ADMER, converted microlayers together in a ratio of 1: 2 to form a core with a total thickness of 15% of the structure, with a total content of 5% in N171V film structure. The film thickness of 3.36 mils (85.34 micrometers) has oxygen permeability at 23 ° C and relative humidity (RH) 80% at 0.19 cm3 / 100 in2 / day / atm (2.95 cm3 / m2 · 24 hr · atm). It calculated the permeability of 0,031 cm3-mil / 100 in2 / day / atm (0.48 cm3 · 25.4 mm / m 2 · 4 hours · atm). This is 60% of the oxygen permeability of the control-layer structure 7.
EXAMPLE 6
Another example of the invention was prepared using the equipment described in Example 5, and the extrusion conditions as shown in Table 2.
Micro-structure obtained with 10% N171V. This structure has N171V and bonding layer BYNEL / ADMER, converted microlayers together in a ratio of 1: 2 to form a core with a total thickness of 20% of the structure, with an overall 10% concentration in N171V film structure.
PolimerSloy% throughout plenkeChislo sloev58% DOWLEX ™ 2045.11G / 42% ELITE ™ 5230GELITE 5230301EVA 3170101Lotryl EMA 29MA032,5110% EVALCA H171B microlayers transformed into a mixture of 10% (50% bynel 3861 / admer nf498A) 2027Lotryl EMA 29MA032,51Dupont EVA 317 015 158 % DOWLEX ™ 2045.11G / 42% ELITE ™ 5230GELITE 5230201
This microlayer film has a thickness of 3.59 mil (91.18 microns) with a permeability to oxygen at 23 ° C and RH 80% at 0.29 cm3 / 100 in2 / day / atm (4.50 cm3 / m2 · 24 h · atm). It calculated the permeability of 0.104 cm3-mil / 100 in2 / day / atm (1.61 cm3 · 25.4 mm / m 2 · 24 hr · atm).
These data show that the Example 5, a film with a thickness of 3.36 mil (85.34 microns), with only 5% N171V has lower oxygen permeability than either Comparative Example 5, a core 27 layers of 10% N171V . This is because the percentage of N171V divided into thinner layers than optimized crystallization and crystal size N171V, to reduce oxygen permeation.
COMPARATIVE EXAMPLE 7
Tested properties of the film with the same structure as obtained in Comparative Example 5. This multilayer film having a thickness of 3.7 mils (94 microns) had a value of impact resistance, measured by the falling weight, 121 grams, or 32.7 g / mil (1 29 g / m) (standard ASTM D1709). This sample had a tensile strength of Elmendorf in the longitudinal direction (MD) of 24 g / mil (0.94 g / micron), and a tensile strength of at Elmendorf cross direction (TD) of 28 g / mil (1.1 g / m ) (standard ASTM D1922).
EXAMPLE 7
The following example was prepared according to the invention with the equipment described in Example 5, using the same N171V, as Comparative Example, and transformed into microlayers with the binder layer to obtain a core of 27 layers. The sample was prepared under conditions as shown in Table 2. The structure is as follows:
PolimerSloy% throughout plenkeChislo sloevDOWLEX ™ Dow 2247G LLDPE301DOWLEX ™ 2247G LLDPE10150% BYNEL 3861/50% BYNEL 38602,515% EVALCA H171B microlayers transformed into a mixture of 10% 3861152750% BYNEL 3861/50% BYNEL 38602,51DOWLEX ™ 2247G LLDPE2247G201DOWLEX ™ 2247G LLDPE2247G201
This structure has N171V and bonding layer BYNEL, converted microlayers together in a ratio of 1: 2 to form a core with a total thickness of 15% of the structure, with a total content of 5% N171V. Value of impact strength, measured by the falling weight to the film with a thickness of 4.25 mils (107.95 m) of 259 or 60.9 g / mil (2.4 g / m) (standard ASTM D1709). This sample has a tensile strength of Elmendorf in the longitudinal direction (MD) 44,5 g / mil (1.75 g / micron), and a tensile strength of at Elmendorf cross direction (TD) 50.4 g / mil (1.98 g / m) (standard ASTM D1922).
Another micro-laminate structure according to the invention was prepared on the equipment of Example 5 using the 10% level N171V microlayers. Sample prepared using the conditions of Table 2.
PolimerSloy% throughout plenkeChislo sloevDOWLEX ™ 2247G LLDPE301DOWLEX ™ 2247G LLDPE10150% BYNEL 3861/50% BYNEL 38602,5110% EVALCA H171B microlayers transformed into a mixture of 10% 3861202750% BYNEL 3861/50% BYNEL 38602,51DOWLEX ™ 2247G LLDPE201DOWLEX ™ 2247G LLDPE151
The film with a thickness of 3.94 mils (100.08 m) has a value of impact resistance, measured by the falling weight, 189 grams, or 48 grams / mil (1.89 g / micron) (standard ASTM D1709). This sample has a tensile strength of Elmendorf in the longitudinal direction (MD) 19.8 g / mil (0.78 g / micron), and a tensile strength of at Elmendorf cross direction (TD) 16.8 g / mil (0.66 g / m) (standard ASTM D1922).
The third film was produced on the equipment of Example 5 with conditions of Table 2.
PolimerSloy% throughout plenkeChislo sloevDOWLEX ™ 2247G LLDPE301DOWLEX ™ 2247G LLDPE101Lotryl 29MA032,515% EVALCA H171B microlayers transformed into a mixture of 10% 29MA0301527Lotryl EMA 29MA032,51DOWLEX ™ 2247G LLDPE201DOWLEX ™ 2247G LLDPE151
The film with a thickness of 3.23 mils (82.04 micrometers) has the value of impact resistance, measured by the falling weight, 370 grams or 114.5 g / mil (4.5 g / m) (standard ASTM D1709). This sample has a tensile strength of Elmendorf in the longitudinal direction (MD) 97 g / mil (3.82 g / micron), a tensile strength of at Elmendorf cross direction (TD) 259 g / mil (10.19 g / micron) (standard ASTM D1922).
Two of micro structures with 5% N171V divided into thin layers, indicate that the toughness can be increased by optimizing the thickness of the individual layers for controlling the crystallization. 10% EVOH, which would have a thicker individual layers showed a low toughness compared with a 5% levels.
Table 1PolimerPostavschikIndeks melt (temperature of 190 ° C / 2.16 kg), the ASTM standard D1238Plotnost (g / cm3), the standard ASTM D792 or ISO 1183% somonomeraDOWLEX ™ 2247GDow Chemical2,00,917 DOWLEX ™ 2245.11GDow Chemical1,00,922 ELITE ™ 5230Dow Chemical4, 00.916 Bynel l3861Dupon2,00,95Privity anhydride ethylene vinilatsetataBynel l3860Dupon5,70,96Privity anhydride copolymer vinilatsetataEVALCA H171BKuraray1,71,17Sopolimer ethylene and ethylene-vinyl alcohol copolymer (38 mole percent ethylene) Lotryl EMA 29MA03Arkema2,0-3,5 - Ethylene and methyl acrylate (27-31% methyl acrylate (MA)) in accordance with Admer nf498AMitsui3,00,910 ASMT D1505Modifitsirovanny poliolefinElvax 3170Dupon2,50,94Sopolimer ethylene and vinyl acetate (18% vinyl acetate (VA))
Table 2Usloviya ekstruziiEkstruder1234567 ObolochkaSvyazuyuschy sloyBarerny sloySvyazuyuschy sloyObolochkaObolochkaInkapsuli-rovanieRazmer in dyuymah44,45 mm38,1 mm44,45 mm38,1 mm44,45 mm44,45 mm31,75 mmZona S193,33 1193,33 ° ° ° S193,33 S193,33 ° S193 33 ° ° S193,33 S176,67 ° SZona 2204,44 ° S204,44 S204,44 ° ° ° S204,44 S204,44 S204,44 ° ° ° SZona S204,44 3215,55 ° S215,55 ° C215 55 ° S215,55 S215,55 ° ° ° S215,55 S215,55 ° SZona shift
Contents9
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| Document | Relation | Office | Cited during |
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| RU196405U1 | Cited by | Russian Federation | Search report |
| WO9703803A1 | Cites | World Intellectual Property Organization (WIPO) | – |
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| Document | Office | Kind | Date |
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| 15439209 | United States of America | P | |
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| RU2011138612A | Russian Federation | A | |
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| RU2500540C2This record | Russian Federation | C2 | |
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Numbers
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- Publication, EPODOC
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Titles2
- Russian
- МНОГОСЛОЙНЫЕ СТРУКТУРЫ, ИМЕЮЩИЕ КОЛЬЦЕОБРАЗНЫЕ ПРОФИЛИ, И СПОСОБЫ И УСТРОЙСТВО ДЛЯ ИХ ПОЛУЧЕНИЯ
- English
- SANDWICH STRUCTURES WITH CIRCULAR PROFILES, METHOD AND DEVICE FOR THEIR PRODUCTION
Classification
- CPC, 58
- B29C49/22
- B32B1/08
- B29C55/28
- B29L2023/001
- B32B37/00
- B32B37/153
- B32B5/18
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- B32B2266/0214
- B32B2270/00
- B32B2272/00
- B32B2307/50
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- B32B2307/546
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- B32B2307/72
- B32B2307/7242
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- B32B2597/00
- Y10T428/1393
- Y10T428/1352
- B29C48/09
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- B29C48/185
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- B29C48/335
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- B29C48/10
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- IPC, 11
- B32B27 06
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- B29C48 10
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