Polymeric compositions and films, plural layer sheet structures and packaging made from such films and structures
Abstract
A POLYMERIC COMPOSITION IS A DISTILLED OF A FIRST COMPONENT COMPRISING POLYPROPYLENE, A SECOND COMPONENT CONTAINING AN ETHYLENE-BASED COPOLYMER, AND A THIRD COMPONENT WHICH MAY BE AN ELASTOMERIC POLYMER. THE DISTILLATES ARE USEFUL TO MAKE SINGLE AND MULTILAYER STRUCTURES. SUCH STRUCTURE INCLUDES A FIRST LAYER (12) MADE OF SUCH DISTILLED AND A SECOND LAYER (14) OF A POLYMER RESISTANT TO MISTREATMENT, SUCH AS POLYPROPYLENE. OPTIONALLY THE STRUCTURE INCLUDES SOME LAYERS. THE DISTILLATE LAYER (12) CAN BE USED AS A HEAT SEALING MEDIA (28) BETWEEN THE LAYERS OF THE LAMINATE STRUCTURE TO MAKE A PACKAGING BAG (30), AND IS ABLE TO WITHSTAND DISTORTION WITHOUT SIGNIFICANT DAMAGE.

Term
Term ended
Expired 28 November 2006, 19.8 years ago.
- Priority
- Filed
- Granted
- Expired
- Today
24 claims: 16 independent, 8 dependent
- 1REIVINDICACIONES 1. Un método de fabricar una película polímera adecuada para un uso en envasado, que comprende la operación de mezclar:(a) de 40 a 70% en peso de un primer componente que comprende un polímero de polipropileno;(b) un segundo componente que comprende un copolímero basado en etileno, de etileno y un segundo grupo que comprende o bien propileno o bien buteno-1;y (c) un tercer componente, diferente del segundo componente, que proporciona propiedades elastoímeras;y conformar la mezcla a la forma de una película.
- 2Un míetodo de acuerdo con la reivindicaciíon 1, en el que el segundo componente se encuentra presente en una proporciíon de 5% a 35% en peso de la composicioín global de dicha mezcla.
- 3Un míetodo de acuerdo con la reivindicaciíon 1, o la reivindicaciíon 2, en el que el segundo componente incluye o consta esencialmente de un copolímero de 85 a 95% en moles de etileno y de 15 a 5% en moles de buteno-1.
- 4Un míetodo de acuerdo con la reivindicaciíon 1, o la reivindicaciíon 2, en el que el segundo componente incluye o consta esencialmente de un copolímero de 60 a 80% en moles de etileno y de 40 a 20% en moles de propileno.
- 5Un míetodo de acuerdo con cualesquiera de las reivindicaciones 1 a 4, en el que el tercer componente se encuentra presente en una proporcioín de 10% a 40% en peso de la composiciíon global de dicha mezcla.
- 6Un míetodo de acuerdo con cualquiera de las reivindicaciones 1 a 5, en el que la composiciíon del tercer componente se selecciona de copolímeros basados en etileno, polibutileno, poliisobutileno, terpolímero de etileno-propileno-monoímero diíenico, copolímero de bloques de estirenobutadieno-estireno, copolímeros de bloques de estireno-etileno/butileno-estireno, copolímero de bloques de estireno-isopreno-estireno, polibuteno1 y copolímero de isobutileno-isopreno.
- 7Un míetodo de acuerdo con cualesquiera de las reivindicaciones precedentes, en el que el segundo componente se encuentra presente en una cantidad de 5% a 35% en peso de la composicioín global de la mezcla, el tercer componente se encuentra presente en una proporcioín de 10% a 40% en peso de la composicioín global de la mezcla, y en el que la composiciíon del tercer componente se selecciona de un copolímero de bloques de estireno-butadieno-estireno, un copolímero de bloques de estireno-etileno/butileno -estireno, un copolímero de bloques de estirenoisopreno -estireno y un poliisobutileno.
- 8Un míetodo de acuerdo con cualesquiera de las reivindicaciones precedentes, en el que el segundo componente se encuentra presente en una proporciíon de 5% a 35% en peso de la composicioín global de dicha mezcla, y comprende un copolímero de 85 a 95% en moles de etileno y de 15 a 5% en moles de buteno-1.
- 9Un míetodo de acuerdo con la reivindicaciíon 8, en el que la composiciíon del tercer componente se selecciona de copolímeros basados en etileno, polibutileno, poliisobutileno, terpolímero de etileno-propileno-monoímero diíenico, copolímero de bloques de estireno-butadieno -estireno, copolímero de bloques de estireno-etileno/butileno -estireno, copolímero de bloques de estirenoisopreno -estireno, polibuteno-1 y copolímero de isobutileno-isopreno.
- 10Una estructura laminar de capas muíltiples que comprende:(a) una primera capa (12) cuya composicioín incluye (i) 40 a 70% en peso de un primer componente que comprende un polímero de polipropileno, (ii) un segundo componente que comprende un copolímero basado en etileno, de etileno y un segundo grupo que comprende o bien propileno o bien buteno-1;y (iii) un tercer componente diferente del segundo componente, que proporciona propiedades elastoímeras;y (b) una segunda capa (14) adherida a la primera capa (12), no siendo la segunda capa una mezcla de polietileno y un modificador.
- 11Una estructura laminar de capas muíltiples que comprende:(a) una primera capa (16) de hoja metaílica que tiene dos superficies opuestas en caras opuestas de la capa de hoja;(b) una segunda capa (14) de un polímero resistente a los abusos y malos tratos adherida a una de las superficies de la hoja;y (c) una tercera capa (12) adherida a dicha estructura laminar sobre la otra de las superficies de la hoja, siendo la composiciíon de la tercera capa una mezcla de (i) 40 a 70% en peso de un polímero de polipropileno, (ii) un copolímero basado en etileno que comprende un copolímero de etileno y un segundo grupo que comprende o bien propileno o bien buteno-1, y (iii) un tercer componente diferente del segundo componente, que proporciona propiedades elastíomeras.
- 12Una estructura laminar de acuerdo con la reivindicaciíon 10 oí la reivindicaciíon 11, en la que dicho segundo componente se encuentra presente en una proporciíon de 5% a 35% en peso de la composicioín global de dicha mezcla.
- 13Una estructura laminar de acuerdo con cualesquiera de las reivindicaciones 10 a 12, en la que el segundo componente comprende un copolímero de 85 a 95% en moles de etileno y de 15 a 5% en moles de buteno-1.
- 14Una estructura laminar de acuerdo con cualesquiera de las reivindicaciones 10 a 12, en la que el segundo componente comprende un copolímero de 60 a 80% en moles de etileno y de 40 a 20% en moles de propileno.
- 15Una estructura laminar de acuerdo con cualesquiera de las reivindicaciones 10 a 15, en la que el tercer componente se encuentra presente en una proporcioín de 10% a 40% en peso de la composicioín global de dicha mezcla.
- 16Una estructura laminar de acuerdo con cualesquiera de las reivindicaciones 10 a 15, en la que la composicioín del tercer componente se selecciona de copolímeros basados en etileno, polibutileno, poliisobutileno, terpolímero de etileno-propileno-moníomero de dieno, copolímero de bloques de estireno-butadieno-estireno, copolímero de bloques de estireno-etileno/butilenoestireno, copolímero de bloques de estirenoisopreno-estireno, polibuteno-1, y copolímero de isobutileno-isopreno.
- 17Una estructura laminar de capas muíltiples, que comprende:(a) una primera capa (18) de una poliamida que tiene dos superficies 2 018 782 en caras opuestas de la misma, (b) una segunda capa (20) de un copolímero de etileno y alcohol vinílico que tiene dos superficies opuestas, una de las cuales estaí dispuesta sobre una superficie de la primera capa (18);(c) una tercera capa (22) de una poliamida dispuesta sobre la otra superficie de la segunda capa;y (d) una cuarta capa (12) adherida a dicha estructura laminar sobre la otra superficie de la primera capa, siendo la composicioín de la cuarta capa una mezcla de (i) 40 a 70% en peso de un polímero de polipropileno, (ii) un copolímero basado en etileno que comprende un copolímero de etileno y un segundo grupo que comprende o bien propileno o bien buteno-1 y (iii) un tercer componente diferente del segundo componente, y que proporciona propiedades elastíomeras.
- 18Una estructura laminar de capas muíltiples que comprende:(a) una primera capa (24) de un material de barrera que tiene dos superficies opuestas en caras opuestas de la misma, siendo la composicioín de la primera capa un copolímero de cloruro de vinilideno;(b) una segunda capa (14) de un polímero resistente a los abusos y malos tratos adherida a una de las superficies de la primera capa (24);y (c) una tercera capa (12) adherida, en dicha estructura laminar sobre la otra cara de la primera capa (24), siendo la composicioín de la tercera capa una mezcla de (i) 40 a 70% en peso de un polímero de polipropileno, (ii) un copolímero basado en etileno que comprende un copolímero de etileno y un segundo grupo de propileno o buteno-1, y (iii) un tercer componente diferente del segundo componente, y que proporciona propiedades elastíomeras.
- 19Una estructura laminar de acuerdo con la reivindicaciíon 17 oí la reivindicaciíon 18, en la que la el segundo componente se encuentra presente en una proporciíon de 5% a 35% en peso de la composicioín global de dicha mezcla.
- 20Una estructura laminar de acuerdo con cualesquiera de las reivindicaciones 17 a 19, en la que el segundo componente comprende un copolímero de 85 a 95% en moles de etileno y de 15 a 5% en moles de buteno-1.
- 21Una estructura laminar de acuerdo con cualesquiera de las reivindicaciones 10 a 19, en la que el segundo componente comprende de 60 a 80% en moles de etileno y de 40 a 20% en moles de propileno.
- 22Una estructura laminar de acuerdo con cualesquiera de las reivindicaciones 17 a 21, en la que el tercer componente se encuentra presente en una proporcioín de 10% a 40% en peso de la composicioín global de la mezcla.
- 23Una estructura laminar de acuerdo con cualesquiera de las reivindicaciones 10 a 21, en la que la composicioín del tercer componente se selecciona de copolímeros basados en etileno, polibutileno, poliisobutileno, terpolímero de etileno-propileno-moníomero de dieno, copolímero de bloques de estireno-butadieno-estireno, copolímero de bloques de bloques de estirenoetileno/butileno-estireno, copolímero de bloques de estireno-isopreno-estireno, polibuteno-1 y copolímero de isobutileno-isopreno.
- 24Un envase hecho a partir de una estructura laminar de acuerdo con cualesquiera de las reivindicaciones 10 a 23. 2 018 782 2 018 782
Independent claims24
77 paragraphs in 1 section, as filed
DESCRIPTION
The present invention relates to polymer compositions and films, multilayer laminar structures and containers made from such films and structures.
The packaging industry makes and uses many sheet structures for the manufacture of packages such as heat-sealed containers. Such containers find use in a multitude of applications. Particularly interesting in this report are the applications in which the finished package can be subjected to relatively abusive physical shocks, for example falling or abolishing. In cases where the container contains fluid components, the shock can be transferred to all parts of the container by the contained fluid. The transferred shock can be effective in causing the container to fail at its weakest point, when the severity of the shock is large enough, even if the initial hit is not exercised at the weakest point.
Heat-sealed containers tend to fail at or near a heat seal. Typical faults occur on the surface of the hermetic closure by partial reciprocal detachment of the hermetic closure layers that they face. If the shock is strong enough, the container may have a catastrophic failure in which the container can be pierced outwards.
Such failure of the container, either by partial detachment or catastrophic failure, compromises the containment and protective functions of the container and is therefore not acceptable. It is desirable to find compositions of materials that can be used in laminar container structures to improve the capacity of the laminar structure, and particularly the hermetic closure agent layer, to resist increased amounts of abuse and abuse of the type of shocks.
In certain packaging applications, the containers are subjected to heat treatment at elevated temperatures of up to about 121 ° C as part of the packaging process. Such heat treatments are common in certain packaging of medical supplies and stable food in storage.
Some polymers, such as polypropylene, which are therefore excellent for use in high temperature applications, tend to weaken after being subjected to such heat treatments. The increasing fragility leads to a reduced capacity to resist abuse and abuse of the type of shocks. Although the use of such materials is desirable in terms of their ability to withstand the thymic treatment without container failure during the thymic treatment, the resulting fragility is an undesirable characteristic in that it affects their ability to withstand the shocks caused, for example , by transport and handling.
It is an object of this invention to create new compositions for mixing materials, single layer films as well as multilayer films and laminar structures, which incorporate the new compositions, for use in the manufacture of packages and particularly hermetically sealed containers.
It is also desired to create heat-sealed containers capable of withstanding increased amounts of abuse and ill-treatment of the type of physical shocks, especially after the sealed and then sealed packaging has been subjected to high temperatures of up to 121<sup>°</sup>C.
British patent document GB-A2.055.668 refers to packaging materials that have, among others, an improved ability to seal. The packaging film according to GB-A-2,055,668 comprises a base film of a propylene polymer coated with a mixture of (A) a copolymer of propylene and ethylene in which propylene predominates, (B) a propylene copolymer and an α-olefin having 4-10 carbon atoms in which propylene predominates and (C) a butene copolymer and an α-olefin having 2-10 carbon atoms predominates butene. The coating formulation may comprise components (A), (B) and (C) together or a combination of any two of the components (A), (B) and (C).
In contrast to GB-A-2,055,688, in accordance with the present invention a polymeric film is created comprising a mixture of:
(a) 40 to 70% by weight of a first component comprising a polypropylene polymer;
(b) a second component comprising a copolymer based on ethylene, ethylene and a second group comprising either propylene or butene-1; and (c) a third component, different from the second component, that provides elastomeric properties.
European Patent Application no. 86309313.4, publication No EP-A-0 229 475 of the present applicant was filed at the EPO on the same day as this Patent Application and claims the same priority date.
European Patent Application No. 86 309 313.4 claims, in claim 1<sup>to</sup>:
A multilayer film that includes first and second layers adhered to each other, the first layer being a mixture of (i) a polypropylene (ii) an ethylene-based copolymer and a Modifier, and the second layer being a mixture that includes a Modifier, characterized in that the second layer is a mixture of polyethylene and a Modifier, and because the Modifier of the first layer has a different composition of the ethylene-based copolymer (EBC, English Ethylene Based Copolymer). The first layer Modifier can be an elastomer.
In accordance with claim 2- of that patent application also being processed, the first component is present in a proportion of 40-70% by weight of the first layer, and in accordance with claim 3<sub>-</sub><sup>to</sup>, the second component of that layer consists of ethylene copolymerized with propylene or butene-1.
The film will be observed, the object of these claims of the patent application
018 782 also in process, the second layer is a mixture of polyethylene and a Modifier.
The present patent application, insofar as it claims multiple layer films, ceases to expressly claim such films in which the second layers thereof comprise mixtures of polyethylene and a Modifier, and therefore, the present invention creates a laminar structure of multiple layers comprising:
(a) a first layer (12) whose composition includes (i) 40 to 70% by weight of a first component comprising a polypropylene polymer, (ii) a second component comprising an ethylene-based copolymer of ethylene and a second group comprising either propylene or butene-1; and (iii) a third component different from the second component, which provides elastomeric properties; and (b) a second layer (14) adhered to the first layer (12), the second layer not being a mixture of polyethylene and a modifier.
In the new mixing composition, the film and the laminar structure defined above, the second component is an ethylene-based copolymer (hereinafter referred to as sometimes EBC) consisting of ethylene copolymerized with groups of a second molecule, the latter being either propylene or butene-1. In EBC ethylene predominates. The third component mentioned above is an elastoimer polymer that can be an elastomeric EBC. (In the following, the third group of material components referred to above as the "third component" is sometimes referred to herein).
Preferably, the second component is present in a proportion of 5% to 35% by weight of the overall composition of the mixture of which it is a part.
In a preferred embodiment, the ethylene-based copolymer is a copolymer of 85 to 95 mol% of ethylene and 15 to 5 mol% of butene-1. In another embodiment, it is a copolymer of 81-94 mol% ethylene and 19-6 mol% butene-1.
In another preferred embodiment, the ethylene-based copolymer is essentially a copolymer of 60 to 80 mol% of ethylene and 40-20 mol% of propylene.
It is preferred that the third component composition be selected from the group of elastomers comprising polybutylene, polyisobutylene, terpolymer of ethylene -propylene-diienic monomer, styrene-butadiene styrene block copolymer, styrene-ethylene / butylene-styrene block copolymer, polybutene -1, styrene-isoprene-styrene block copolymer, isobutylene-isoprene copolymer, or the group of ethylene-based copolymers.
Therefore, in a family of preferred compositions, the first component is present in a proportion of 40% to 70% by weight, the second component is present in a proportion of 5% to 35% by weight and third component It is present in a proportion of 10% to 40% by weight. In that family of global compositions, the third component composition is desirably selected from a styrene-butadiene-styrene block copolymer, a styrene-ethylene / butylene-styrene block copolymer, a styrene-isoprene-styrene block copolymer , and a polyisobutylene.
The aforementioned composition constitutes the basis of single layer films, multilayer films and multilayer laminar structures that materialize the invention.
In a multilayered laminar structure according to the invention, a first layer is made of metal sheet having two opposite surfaces on opposite faces thereof, a second layer of a polymer resistant to abuse and abuse adheres to a of the surfaces of the sheet, and a third layer adheres to the sheet structure on the other of the surfaces of the sheet, the composition of the third layer being a mixing composition according to the invention as defined hereinbefore.
In another multilayered laminar structure according to the invention, a first layer is made of a polyamide having two opposite surfaces on opposite faces thereof, a second layer of a copolymer of ethylene and vinyl alcohol, which has two opposite surfaces , a surface of the second layer is disposed on a surface of the first layer, a third layer of a polyamide is disposed on the other surface of the second layer opposite the first layer, and a fourth layer adheres to the laminar structure on the other side of the first layer, the fourth layer being a mixing composition according to the invention.
Still in another multilayered laminar structure of the invention, a first layer is made of a barrier material having two opposite surfaces on opposite faces thereof, the composition of the first layer being a copolymer of vinylidene chloride, a second The layer of an abuse-resistant polymer adheres to a surface of the first layer, and a third layer adheres to the laminar structure located on the other side of the first layer. the composition of the third layer being a mixing composition according to the invention.
Containers of various types such as bags or sachets, which may or may not be hermetically sealed by heat, can also be made of films and sheet structures in accordance with the invention. The invention includes these containers when they are ready to be loaded and filled, and in the state after loading, filling and closing them.
Embodiments of the invention will now be explained in more detail in the following description, which is given by way of example only and with reference to the accompanying drawings, in which:
FIGURE 1 is a cross section of a portion of a 2 layer film according to the invention,
018 782 FIGURE 2 is a cross section of a portion of a 3-layer sheet structure according to the invention in which a metal sheet layer is incorporated as a barrier layer, FIGURE 3 is a cross section of a portion of a 4-layer film according to the invention, FIGURE 4 is a cross-section of a portion of another 3-layer film according to the invention, in which a polymeric barrier material is incorporated as an inner layer, and FIGURE 5 is a perspective view of a tactical bag made in accordance with the invention.
The invention comprises a plurality of forms and embodiments. In its most generic form, the invention consists of a composition of matter formed by the joint intimate mixing of various mixing components. The invention can also be represented by a variety of articles that can be shaped such as molding or extruding the mixing composition. A preferred form of an elaborated article is a film of a single-layer container that can be shaped by conventional extrusion procedures. Such films are typically thin and flexible, being of the order of 0.025 to 0.20 mm thick. Also thicker sections and shapes can be formed, as regards other uses.
Other preferred embodiments of the invention are those in which the mixing composition is used to form a layer of a laminar structure of plural or multiple layers. Representative of these films are those illustrated in FIGURES 1-4. The laminar structures according to the invention have two, three, four or more than four, p. eg, five independent layers adhered to each other, using more intermediate layers of adhesive if necessary.
Turning now to FIGURE 1, layer 12 is a layer of a new mixing composition according to the invention and layer 14 is formed of a polymer resistant to abuse and ill-treatment, such as polypropylene. A film of a Ullic layer according to the invention will have a composition equivalent to that of said layer.
12.
The structure of FIGURE 1 illustrates a simpler form of containers of the invention. It is advantageous because of its simplicity, and can find use in applications where high levels of protection against gaseous diffusioan are of utmost importance.
When protection against gas diffusion is more important, a layer of a barrier material is used. In the three layer structure of FIGURE 2, the additional layer 16 is a metallized sheet layer that provides an excellent barrier to gas diffusion. Layer 14 is the layer of a polymer resistant to abuse and maltreatment and layer 12 is the layer of mixing composition as in FIGURE 1.
The structure of FIGURE 2 is representative of a laminar structure useful for manufacturing bags susceptible to retort treatments. Such structures can also be used for applications where the package is not subject to retort treatment conditions. In those cases, it is not necessary to evaluate the specific materials selected for each layer in terms of their ability to withstand the retort treatment procedure. The typical problems encountered in the retort treatment are excessive softening during the treatment, or a embrittlement resulting from the treatment. The sheet layer 16 of one of such containers capable of retort treatment is 0.007-0.025 mm, with thinner gauges being preferred for economic reasons. The layer 14 resistant to abuse and ill-treatment can be any of the polymers resistant to abuse and ill-treatment, conventionally known. These include, for example, nylon, oriented nylon, oriented polypropylene and oriented polyester. For use in packaging with retort treatment, layer 14 is 0.013 mm, with a range of 0.006-0.025 mm. It is conventionally known to achieve adhesion between the sheet layer 16 and the abuse and abuse layer 14 by means of adhesives such as polyester-urethane curing type adhesives. These adhesives are acceptable for such use in this invention.
The mixing layer 12 can be any of the mixing compositions according to the invention. The structure of FIGURE 2 is planned so that layer 12 can be used as a heat seal layer. A minimum thickness to achieve strong heat seals is 0.025 mm, so that this constitutes a preferred minimum thickness. Thick heat seal layers up to 0.10 mm can advantageously provide more efficient use in heat seal material; and this is a maximum thickness generally preferred. Although the layer 12 may be much thicker, for example, 0.20 mm or more, and this is comprised by the scope of the invention, usually no material benefit is derived from the use of the additional material; therefore, larger thicknesses are generally not preferred.
Layer 12 may be adhered to layer 16 by a conventional adhesive of the polyester-urethane curing type. Alternatively, adhesion can be achieved by other methods such as by extrusion stratification, coextrusion stratification, or extrusion coating followed by heat and pressing in a hot pass. In some cases it may be desirable to use a primer on the surface of sheet layer 16 before adhering layers 12 and 16 between sheets.
Turning next to FIGURE 3, layer 12 is a mixing composition according to the invention as in FIGURES 1 and 2. Layer 18 is a polyamide. Layer 20 is a copolymer of ethylene and vinyl alcohol. Layer 22 is a polyamide.
The structure of FIGURE 3 generically represents a family of laminar structures that provides an effective barrier to the transmission of oxygen through the laminar structure while allowing transparen4
018 782 of the packaging material in terms of visibility of the packaged contents. These packages have a variety of uses, and the selection of specific polymers and specific combinations of polymers depends on the particular use considered. A typical use is, as regards the structure of FIGURE 2, that of packaging with retort treatment.
It is known to coextrude a multilayer film structure in which a layer of copolymer of ethylene and vinyl alcohol is between two layers of polyamide. Such a structure is observed in the substructure of layers 18, 20 and 22. It has also been found acceptable to include layer 12 as part of the coextrusion. Therefore, the structure of FIGURE 3 can be produced advantageously and economically in a single treatment operation by coextruding all four layers simultaneously and combining them in the coextrusion process to form the sheet structure of multiple layers.
To obtain improved adhesion between layers 12 and 18, it is sometimes desirable to include an adhesive, such as an adhesive polymer, between layers 12 and 18. Such materials are conveniently known and can be selected based on the specific compositions of the layers. 12 and 18 and in the procedure to be used. Typical of these adhesive polymers are those based on polypropylene and which have modifications therein with carboxyl groups, such as maleic acid or maleic anhydride.
Of course, the structure can be made by other procedures but generally they would be mine, and therefore those procedures are less preferred. Illustrative of these are adhesive stretification, in which the layers can be bonded using, for example, an adhesive of the polyether urethane curing type.
It is intended that the term polyamide, then used to describe the compositions of layers 18 and 22, include copolymers and polyamide alloys as the main component. Similarly, additives that are normally used with a polyamide are acceptable in this invention and therefore are included in the compositions of layers 18 and 22. Although the compositions of layers 18 and 22 are usually the same, to facilitate coextrusion of the sheet material may be different and the process can be adapted accordingly.
It is intended that the ethylene vinyl alcohol copolymer term, then used to describe the composition of layer 20, include the copolymer alone and mixtures of ethylene and vinyl alcohol with other polymers. Likewise, additives that are normally used with a copolymer of ethylene and vinyl alcohol are acceptable in this invention and are therefore included in the composition of layer 20.
The term "elastomer" includes polymers, copolymers or rubbers that at room temperatures can be stretched substantially under reduced tension and, for immediate relief of the tension, tend to return generally to the original form.
The mixing layer 12 can be any of the mixing compositions that materialize the invention. The structure of FIGURE 3, as in FIGURES 1 and 2, is planned so that layer 12 can be used as a heat seal layer. In this structure, a minimum thickness to achieve strong heat-tight seals is also 0.025 mm, so that this is a preferred minimum thickness. My thick heat sealing layers of up to 0.10 mm can advantageously provide more efficient use of the heat seal material; so that it is a generally preferred maximum thickness. The layer 12 can also be mine thick, as described below for the corresponding layer 12 of FIGURE 2.
The layer 12 may also be less than 0.025 mm, for example, in all the illustrated embodiments, in which no heat seal is used or the force of the seal is not critical.
Turning now to FIGURE 4, layer 14 is a layer resistant to abuse and abuse as in FIGURE2. The layer 12 is of a mixing composition according to the invention as in FIGURES 1-3. Layer 24 is an oxygen barrier layer such as a vinylidene chloride copolymer. Preferred copolymers are a vinylidene chloride copolymer. The copolymers are a copolymers of vinylidene chloride-vinyl chloride and a copolymer of vinylidene chloride-methyl acrylate. In the structure of FIGURE 4, layer 24 usually has a thickness of 0.008 to 0.051 mm, depending mainly on the oxygen transmission rate that is desired for any given end use. Although adhesion can be achieved by other means, suitable adhesives, such as polyether urethane curing adhesives between the respective layers 12, 24 and 14, are used economically in order to achieve satisfactory adhesion between the layers.
To construct the sheet structure of FIGURE 4, layers 12, 24 and 14 are usually formed separately from each other and then combined to the shape of the multilayer structure shown, by conventional techniques for combining polymer films. In a typical procedure, the layers are joined by conventional adhesive stratification techniques.
As is now apparent from the plurality of multilayer structure illustrated above, the polypropylene blend composition and the second and third components have a useful advantage in a variety of multilayer structures. Of course, one layer of the mixing composition can be used advantageously in combination with any other layer that can adhere to it. Thus, the realization of multiple layers of the invention can be defined generically as a multi-layer sheet material in which the composition of at least one layer consists of a mixture of polypropylene and the second and third components; and in the composition of the other or other layers it does not necessarily need to be restricted except for the purposes of obtaining an adhesion between ca5
018 782 pas acceptable for the intended use. Thus, non-polymeric materials, such as paper and sheet metal, as well as polymeric materials can be used.
The multilayered laminar structures of the invention are advantageously conformed to the shape of vases using heat-tight seals, as illustrated in FIGURE 5. Typically, the portions of the laminar material are placed in face-to-face relationship, facing the layer 12 in a portion to layer 12 of the opposite laminar portion. The heat-tight seals 28 are then formed between the laminar portions around a common periphery to form a container 30 that generally defines a closed area. Usually, a face of the container thus formed is left open, as shown, to effect the introduction of the product. Finally, the full packaging is closed and then sealed tightly by heat sealing along the open lake.
Alternatively, the sheet can be shaped into the shape of a tube forming a longitudinal hermetic closure along the overlapping edges; and a transverse hermetic seal is formed through the width of the tube; all as described, for example, in the US patent document of US-A4,521,437.
This procedure is particularly suitable for use in vertical forming, loading and sealing machines.
To overcome the main problem of fragility of polypropylene in flexible packages, as discussed herein, a number of factors work together in combination. Of importance for the achievement of the objectives of the invention is the incorporation, in the mixing composition, of the second and third components as described hereinbefore. The combined contribution of the second and third components is evidenced by substantially fewer structural failures in the films, sheet structures and containers made from them.
The ethylene-based copolymer of the second component is a two-group copolymer, both groups being present in the polymer backbone. The overall molar realization is from at least 60 to at most 95 mol% of ethylene. Ethylene is copolymerized with propylene or butene-1. In the case of propylene, the molar ratio is most preferably within the range of 20% to 40% propylene and 80% to 60% ethylene. Such material is sold by Mitsui Petrochemical Industries, Ltd. as TAFMER® P. In the case of butane-1, the molar ratio is most preferably within the range of 85% to 95% ethylene, and 15% to 5 Butene-1%. Such material is sold by Mitsui Petrochemical Industries, Ltd. as TAFMER ® A.
The polymer used as the third component is different from the polymer of the second component and can be any of the known and easily available elastomeric polymers or an EBC, and of course mixtures thereof. Examples of readily available elastomeric polymers are polybutylene, polyisobutylene, ethylene-propylene-diienic terpolymer, styrene-butadiene styrene block copolymer, styrene-styrene-styrene block copolymer, polybutene-1 and isobutylene-isoprene copolymer.
The third component may be an ethylene-based copolymer which, however, is not the same as that of the second component since this would effectively form a mixture of two components, rather than a mixture of three components as defined in the following claims. .
The polypropylene used as the first component of the mixture provides mechanical resistance to the laminar structure as well as the ability to withstand high temperatures without excessive softening. The inclusion of the second and third components in the mixing composition provides resilience to the mixing composition.
Any of the polypropylenes can be used in the first component of the mixture. Polypropylenes which are copolymers having 2 to 8 mole percent of ethylene are preferred, since the copolymer provides a certain minimum level of additional resilience to polypropylene, when compared to a homopolymer. The term "polypropylene" is intended, as used herein, to include homopolymers and copolymers except when otherwise specified. If polypropylene is a homopolymer or copolymer, its resilience is demonstrated in this invention, whether it has been treated in retort, or has not been treated in retorts, it is substantially improved by the incorporation of the second and third compounds. Without the incorporation of the second and third components, polypropylene is at least somewhat rigid, either a homopolymer or a copolymer.
For example, a mixture of 60% by weight of polypropylene and 40% by weight of polyisobutylene is superior to the same polypropylene when tested in an unmixed composition, then measured in free fall tests of packages made from them. But these containers with polyisobutylene fail in a 2.74 m drop, making the breakage failure through the wall of the container adjacent to the heat seal.
For comparison, packages were made using a single layer film whose composition was 60% by weight of the same polypropylene copolymer, but consisting of 20% TAFMER<sup>1</sup>® A and 20% polyisobutylene, instead of simply 40% polyisobutylene in the previous example. The resulting packages passed the test of a satisfactory fall of 2.74 m as opposed to the packages made from one and the other of the 2 component mixtures.
Although the polypropylene homopolymer is fully satisfactory for many uses, the polypropylene copolymer is preferred, as evidenced by the optimal properties of improved resistance to abuse and abuse by collisions in combination with the ability to withstand high treatment temperatures. Then, the optimal behavior is generally seen in mixtures of a copolymer of poly6
018 782 propylene with the second and third components.
A lower level of 40% is generally preferred for polypropylene in order to maintain at least a minimum degree of tolerance to the high heat seal temperature of the composition and an important water vapor barrier property that are provided by polypropylene. A higher level of 70% is generally desired.
Although the incorporation of virtually any amount of the second component into the mixing composition would provide some benefit, generally the improvements are apparent for the first time at a 2% by weight level. The desired balance of properties is achieved when the second component is present in a proportion of 5% to 35%.
Similarly, although the incorporation of virtually any amount of the third component into the compositional mixture provided some benefit, generally the improvements are evident for the first time at a 2% by weight level. The desired balance of properties is achieved when the third component is present in a proportion of 10% to 40%.
The inter-relationship between the three components is a mystery, since the use of the second and third components, as described herein, can provide a mixture that has superior properties when compared to the prior art. For any unexplained reason, the most preferred family of compositions of the invention is that in which each component is within its preferred range of compositions; namely 40% to 70% polypropylene, 5% to 35% of the second component and 10% to 40% of the third component.
Thus, it is appreciated that the invention provides new compositions in addition to uonic layer films and multilayer films and sheet structures for use in the manufacture of packages. Of course, the invention provides heat-sealed sealed containers capable of withstanding substantial amounts of abuse and ill-treatment of the type of fossil shocks, whose capacity is especially observable after the sealed and then sealed containers have been subjected to elevated temperatures of up to 121 ° C
018 782
2 sheets
Sheet 1 Sheet 2
64 members in 9 offices
Priority claims5
| Document | Office | Kind | Date |
|---|---|---|---|
| 19850802910 | United States of America | – | |
| 80291085 | United States of America | A | |
| 80291085 | United States of America | A | |
| 19850802910 | – | – | – |
| US19850802910 | – | – | – |
Members64
| Document | Office | Kind | |
|---|---|---|---|
| AU6576786A | Australia | A | |
| AU6576886A | Australia | A | |
| JPS62149441A | Japan | A | |
| JPS62151436A | Japan | A | |
| EP0229475A1 | European Patent Office (EPO) | A1 | |
| EP0230115A1 | European Patent Office (EPO) | A1 | |
| US4764404A | United States of America | A | |
| US4778697A | United States of America | A | |
| AU1976088A | Australia | A | |
| EP0301773A2 | European Patent Office (EPO) | A2 | |
| EP0302711A2 | European Patent Office (EPO) | A2 | |
| AU2003188A | Australia | A | |
| JPS6467337A | Japan | A | |
| EP0322189A2 | European Patent Office (EPO) | A2 | |
| AU2747688A | Australia | A | |
| JPH01174444A | Japan | A | |
| EP0302711A3 | European Patent Office (EPO) | A3 | |
| JPH01269535A | Japan | A | |
| US4894266A | United States of America | A | |
| EP0301773A3 | European Patent Office (EPO) | A3 | |
| AU595557B2 | Australia | B2 | |
| CA1268108A | Canada | A | |
| US4937139A | United States of America | A | |
| EP0380145A1 | European Patent Office (EPO) | A1 | |
| EP0322189A3 | European Patent Office (EPO) | A3 | |
| EP0229475B1 | European Patent Office (EPO) | B1 | |
| AT56665T | Austria | T | |
| EP0230115B1 | European Patent Office (EPO) | B1 | |
| DE3674367D1 | Germany | D1 | |
| US4966795A | United States of America | A | |
| AT57653T | Austria | T | |
| CA1277060C | Canada | C | |
| DE3675184D1 | Germany | D1 | |
| AU604220B2 | Australia | B2 | |
| US5002811A | United States of America | A | |
| ES2018472B3 | Spain | B3 | |
| US5011719A | United States of America | A | |
| ES2018782B3This record | Spain | B3 | |
| GR3001000T3 | Greece | T3 | |
| AU618744B2 | Australia | B2 | |
| US5093164A | United States of America | A | |
| AU622411B2 | Australia | B2 | |
| US5137763A | United States of America | A | |
| GR3001343T3 | Greece | T3 | |
| AU628795B2 | Australia | B2 | |
| US5160767A | United States of America | A | |
| EP0301773B1 | European Patent Office (EPO) | B1 | |
| AT97061T | Austria | T | |
| DE3885529D1 | Germany | D1 | |
| DE3885529T2 | Germany | T2 | |
| US5407751A | United States of America | A | |
| JPH0737128B2 | Japan | B2 | |
| CA1336672C | Canada | C | |
| CA1336880C | Canada | C | |
| CA1336881C | Canada | C | |
| JPH08253261A | Japan | A | |
| JP2659036B2 | Japan | B2 | |
| EP0380145B1 | European Patent Office (EPO) | B1 | |
| AT159891T | Austria | T | |
| DE3650654D1 | Germany | D1 | |
| JPH10130439A | Japan | A | |
| DE3650654T2 | Germany | T2 | |
| JP2757959B2 | Japan | B2 | |
| JP2855117B2 | Japan | B2 |
Numbers
- Publication
- 2018782
- Publication, DOCDB
- 2018782
- Publication, EPODOC
- ES2018782
- Application
- 86309312
- Application, DOCDB
- 86309312
- Application, EPODOC
- ES19860309312T
Titles2
- Spanish
- COMPOSICIONES Y PELICULAS POLIMERICAS, ESTRUCTURAS PLURILAMINARES Y EMBALAJE HECHO CON ELLOS
- English
- COMPOSITIONS AND POLYMERIC FILMS, PLURILAMINARY STRUCTURES AND PACKING MADE WITH THEM
Classification
- CPC, 42
- B32B27/32
- B32B27/08
- C08L23/0815
- C08L23/0853
- C08L23/0861
- C08L23/10
- C08L23/12
- C08L23/14
- C08L23/16
- C08L23/20
- C08L23/22
- C08L27/08
- C08L53/02
- C08L77/00
- C08L2205/03
- B29C48/08
- B29C48/185
- Y10T428/1338
- Y10T428/1341
- Y10T428/31739
- Y10T428/31587
- Y10T428/31743
- Y10T428/31913
- Y10T428/31692
- Y10T428/31924
- Y10T428/31605
- Y10T428/31699
- Y10T428/31746
- Y10T428/3192
- B32B27/10
- B32B2325/00
- B32B2307/31
- B32B7/12
- B32B2323/10
- B32B2323/16
- B32B27/302
- B32B2323/04
- B32B15/08
- B32B2439/00
- B32B27/34
- B32B27/304
- B32B2270/00
- IPC, 18
- B32B27 30
- B32B15 085
- B32B27 32
- C08J5 18
- C08L7 00
- C08L21 00
- C08L23 00
- C08L23 08
- C08L23 10
- C08L23 12
- C08L23 14
- C08L23 16
- C08L23 20
- C08L23 22
- C08L27 08
- C08L53 02
- C08L77 00
- C08L101 00