Stretch hoods made from uldpe-rich formulations.

(54) Title: STRETCH COVERS MADE OF FORMULATIONS RICH IN ULDPE.

(54) Title: STRETCH HOODS MADE FROM ULDPE-RICH FORMULATIONS.

(57) Summary

The mono- or multilayer polymeric stretch cover packaging film with a general density not exceeding 0.920 g / cc comprises: A. At least one core layer comprising: 1. At least 50% ps ULDPE with a density 0.900 to 0.9200 g / cc; and 2. Optionally, at least one of: a. LDPE with a density of 0.915 to 0.925 g / cc; and b. EVA with a VA content of 4 to 20% ps; and B. Optionally, two liner layers, each liner layer independently comprises: 1. At least 50% ps ULDPE with a density of 0.900 to 0.920 9 / cc; and 2. Optionally, an LDPE with a density of 0.915 to 0.925 g / cc.

(57) Abstract

Polymeric, mono- or multilayer stretch hood packaging film with an overall density that does not exceed 0.920 g / cc comprises: A. At least one core layer comprising: 1. At least 50 wt% ULDPE with a density of 0.900 f or 0.920 g / DC; and 2. Optionally at least one of: a. LDPE with a density of 0.915 fo 0.925 g / cc, and b. EVA with a VA content of 4 fo 20 wt%; and B. Optionally, two skin layers, each skin layer independently comprising: 1. At least 50 wt% ULDPE with a density of 0.900 f or 0.920 g / cc; and 2. Optionally an LDPE with a density of 0.915 fo 0.925 g / cc. Polymeric, mono- or multilayer stretch hood packaging film with an overall density that does not exceed 0.920 g / cc comprises: A. At least one core layer comprising: 1. At least 50 wt% ULDPE with a density of 0.900 f or 0.920 g / DC; and 2. Optionally at least one of: a. LDPE with a density of 0.915 fo 0.925 g / cc, and b. EVA with a VA content of 4 fo 20 wt%; and B. Optionally, two skin layers, each skin layer independently comprising: 1. At least 50 wt% ULDPE with a density of 0.900 or 0.920 g / cc; and 2. Optionally an LDPE with a density of 0.915 fo 0.925 g / cc. The bladeless turbine ineludes a case, three or more turbine dises disposed within the case. Each turbine disc has a center opening, and two or more of the turbine dises have a set of exhaust ports positioned annularly around the center opening. A drive shaft passes through the center openings of the turbine dises and is attached to the three or more turbine dises, wherein the drive shaft is positioned within the case along the centerline, free for rotate within the case, and extends through the case for connection fo a generator. The one or more fluid / vapor inlets are attached to the main housing such that a fluid / vapor is directed at a specified angle onto the three or more turbine dises. The fluid / vapor outlet is aligned with the centerline. A set of exhaust holes proximate fo and connected fo the fluid / vapor outlet that are positioned annularly around the drive shaft.

<img file="MX350481B_D0001.tif" />

PATENT TITLE No. 350481

Owner (s): DOW GLOBAL TECHNOLOGIES LLC.

Address: 2040 Dow Center, Midland, Michigan, 48674, USA

Denomination: STRETCH COVERS MADE OF FORMULATIONS RICH IN ULDPE.

<td>Classification: CIP: CPC:</td><td>B32B27 / 32; C08J5 / 18 C08J5 / 18; B32B27 / 32; B32B27 / 306; B32B2553 / 00; B65D65 / 22; C08J2323 / 04</td>

Inventor (s): SELIM BENSASON; ANDREAS MAYER; ANTONIO MANRIQUE

<td>Number: MX / a / 2012/015114</td><td>REQUEST International Presentation Date: July 5, 2011</td>

<td>Country: IS</td><td>PRIORITY Date: Number: July 2, 2010 PCT / ES2010 / 070457</td>

Validity: Twenty years

Expiration Date: July 5, 2031

Issue Date: September 7, 2017

The reference patent is granted based on articles 1^or, 2 »fraction V / 6“ useful fraction, and 59 of the Industrial Property Law.

In accordance with article 23 of the Industrial Property Law, this patent is valid for twenty non-extendable years from the date of filing the international application and will be subject to the payment of the fee to keep the rights in force.

Whoever signs this title does so based on the provisions of articles 6, sections III and 7^or bis 2 of the Industrial Property Law (Official Gazette of the Federation (DO Γ) 06/27/1991, amended on 08/02/1994, 10/25/1996, 12/26/1997, 05/17/1999 , 01/26/2004, 06/16/2005, 01/25/2006, 05/06/2009, 06/01/2010, 06/18/2010, 06/28/2010, 01/27/2012 and 09 / 04/2012); items 1^or, 3 * section V subsection a), 4th and 12th sections I and III of the Regulations of the Mexican Institute of Industrial Property (DOF 12/14/1999, amended on 07/01/2002, 07/15/2004, 28 / 07/2004 and 7/09/2007); items 1^or. 3^or. 4^or, 5^or fraction V part a). 16 sections t and III and 30 of the Organic Statute of the Mexican Institute of Industrial Property (DOF 12/27/1999, amended on 10/10/2002, 07/29/2004, 08/04/2004 and 09/13/2007) , 1^or, 3 and 5^or Subsection a) of the Agreement that delegates powers to the Deputy General Directors, Coordinator, Divisional Directors, Heads of Regional Offices, Divisional Deputy Directors, Departmental Coordinators and other subordinates of the Mexican Institute of Industrial Property. (DOF 12/15/1999, amended on 02/04/2000, 07/29/2004, 08/04/2004 and 09/13/2007).

This document is signed with an advanced electronic signature (FIEL), based on articles 7 BIS 2 of the Industrial Property Law; 3 of its Regulations, and 1 section III, 2 section V, 26 BIS and 26 TER of the Agreement establishing the guidelines for the use of the Payment and Electronic Services Portal (PASE) of the Mexican Institute of Industrial Property, in the procedures indicated.

THE DIVISIONAL DIRECTOR OF PATENTS

NAHANNY CANAL REYES

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Original string:

NAHANNY MARISOL CANAL REYES | 00001000000403252793 | Administration Service

Tax | 1695 || MX / 2017/74053 | MX / a / 2012/015114 | PCT patent title | 1027 | RGZ | Page (s) 1 | iljk63FFepz1urBdr3 / qT4vqMWw =

Digital stamp:

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"STRETCH COVERS MADE OF FORMULATIONS

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RICH IN ULDPE "

Cross reference to related requests

This application claims priority to international application number PCT / ES2010 / 070457, filed on July 2, 2010.

Field of Invention

This invention relates to stretch covers. In one aspect, the invention relates to mono- and multilayer stretch tires, while in another aspect, the invention relates to stretch tires in which each of the layers is rich in ultra-low-density polyethylene (ULDPE, for its acronym in English).

Background of the Invention

Polyolefin film formulations used in industrial stretch cover packaging applications require a proper balance between elastic recovery during packaging and load stability during storage and shipping. Elastic recovery in terms of resin design is correlated with low or lower crystallinity resins, while load stability is correlated with high o resins. higher crystallinity.

Industrial stretch cover packaging film structures have been intended for commercial use for “ζ. - _ _ ___—

- «to © many years, and are typically based on film formulations rich in ethylene vinyl acetate (EVA), that is, formulations in which more than 50 percent by weight (% by weight) it is EVA. The typical current film design is a 3-layer co-extruded structure based on an EVA core layer (which most commonly comprises an EVA with a content of units derived from vinyl acetate (VA) of 7.5 to 18% by weight) , and liner layers made from blends rich in metallocene-catalyzed linear low-density polyethylene (mLLDPE). This type of film structure performs well on packaging lines, but at the cost of storage and transportation performance. Specifically, the residual elasticity of such films after the stretching and application process remains high and consequently the load stability performance is limited, and EVA resins are weak in film protection properties on decking such as perforation, the tear propagation and dart throwing impact performance.

WO 2009/109367 teaches coextruded film structures made using 10 to 95% by weight Melt Index Ratio (MIR), Linear Low Density Polyethylene (LLDPE) in the core layer of a multilayer extrusion-blown film structure, to provide highly transparent, easy-processing and strong films. LLDPE is characterized by having, among other properties, a density of 0.91 to 0.94 g / cm³, a melt index (l₂) from 0.05 to 1 grams per 10

-3 minutes (g / 10 min), and a MIR (I21 / I2) greater than 35. The liner layers of the multilayer film structure comprise at least 85% by weight of linear polyethylene (PE) of which at least 75% by weight is an LLDPE with a melt index (MI) less than 35 and not less than 15% by weight is a high pressure polyethylene (HPPE).

US 2005/0037219 teaches a blown film coextruded tube for use as a stretch cover film in which the core layer of the film comprises EVA or a polymer comprising units derived from ethylene, the polymer has (1 ) an MI of 0.05 to 20 g / 10 min, (2) at least 10 per 1,000 carbon atoms of short chain branches containing 5 or fewer carbon atoms, (3) a density of 0.90 to 0.94 g / cm³, and (4) a relaxation time of at least 10 seconds. The liner layers comprise at least 60% by weight LLDPE with a density of 0.91 to 0.94 g / cm³ and hexane extractables less than 1.5% by weight.

EP 1 332 868 B1 teaches a multilayer film that can be used in stretch cover applications, the film comprises a core layer (B) comprising either (1) 10-90% by weight of LLDPE with a lower density than 0.920 kg / m³ and 90-10% by weight of a propylene copolymer comprising 0.3-18% by weight of units derived from ethylene and / or at least α-olefin with a molecule of 4 to 12 carbon atoms and 82-97.7% by weight of units derived from propylene, or (2) 60 to 90% by weight of LLDPE with a density less than 0.920 kg / m³ and 40-10% by weight of an EVA comprising 5-35% in

- 4 IMPI

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weight of units derived from VA and 65-95% by weight of units derived from ethylene. A liner layer (A) comprises low-density polyethylene (LDPE) with a density of 910 to 940 kg / m³, a melting point of 106 to 125 ° C, and a melt flow rate (190 ° C, 2.16 kg, MFR, for its acronym in English) of 0.1 to 1 g / 10 min. The other lining layer (C) comprises a composition of one or more of propylene / ethylene, propylene / butene and propylene / ethylene / olefin copolymers in which the composition has an MFR of 0.5 to 10 g / 10 min and a melting temperature from 128 to 145 ° C.

WO 00/37543 teaches a three-layer film with a mixture of an ethylene / α-olefin copolymer, produced with metallocene, of low density and a predominant amount of EVA with a high amount of VA content in the layer of core, and a blend of ethylene / α-olefin copolymer and a predominant amount of EVA with a low amount of VA content in the liner layers. The liner layers also contain silicon dioxide as an anti-lock friction modifier.

Of continuing interest is the industrial stretch cover packaging film that possesses both packaging and storage and transportation performance.

Brief Description of the Invention

In one embodiment, the invention is a mono- or multilayer film structure based on formulations rich in ULDPE. Such resins, which include current European commercial grades such as

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ATTANE SL 4100 and 4102 available from The Dow Chemical Company, offer better mechanical properties than related EVA resins, for example, offering a significant performance advantage from a cargo storage and transportation perspective. This potential for improved protection performance can also be combined with adequate elasticity and recovery speed performance in packaging machines.

It is important to the success of proper packaging machine performance that the total crystal identity of the film is expressed in the layer and film densities with high-density polymers having a more crystalline character and with density polymers. lower that possess a more amorphous character. With reference to related commercial films, the invention is based on ULDPE-rich core layers comprising either 100% by weight ULDPE or a blend comprising predominantly ULDPE by weight percentage in combination with one or more LDPE and EVA. This leads to a higher crystalline core layer which can then be compensated for with a lower lower crystalline skin layer composition. Instead of mLLDPE-rich liner layers of related stretch cover packaging film, liner layers of the inventive films have reduced crystallinity due to their ULDPE-rich formulations.

In one embodiment, the invention is a polymeric mono- or multilayer stretch tire packaging film with a total density not exceeding 0.920 g / cc and comprising:

<img file="MX350481B_D0006.tif" />

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A. At least one core layer comprising:

1. At least 50% by weight of ULDPE with a density of 0.900 to 0.920 g / cc, and

two. Optionally at least one of:

to. LOPE with a density of 0.915 to 0.925 g / cc and

b. EVA with a VA content of 4 to 20% by weight; Y

B. Optionally, at least one liner layer comprising:

1. At least 50% by weight of ULDPE with a density of 0.900 to 0.920 g / cc, and

two. Optionally at least one of:

to. LDPE with a density of 0.915 to 0.925 g / cc, and

b. EVA with a VA content of 4% by weight at

20.

In one embodiment, the film consists of a single film or monolayer.

In one embodiment, the film consists of two layers of film.

In a two-layer film embodiment, one layer is a skin layer and the other layer is a core layer. In a two-layer film embodiment, both layers are liner layers. In a two-layer film embodiment, both layers are core layers. In a two-layer film embodiment, both layers are compositionally the same.

In one embodiment, the film comprises three layers of films

In a three-layer film embodiment, the film comprises a

-7 IMPI iMSTTTUTO METICANO DE A nOHEEMD core layer and two layers of lining. In a modalid^,á '^^JSWⁱpe

<img file="MX350481B_D0007.tif" />

three layers, the film comprises two thin layers and one¹¹ lining layer. In a three-layer film embodiment, each layer is compositionally the same as the other two layers.

In one embodiment, the film comprises more than three layers of film. In a more than three layer embodiment, the film comprises multiple core layers and two skin layers. In a more than three-layer embodiment, each core layer has the same composition as the other core layers. In a more than three-layer embodiment, at least one core layer is different from the other core layers. In a more than three-layer embodiment, each liner layer is compositionally equal to the other liner layer. In one embodiment, each liner layer is compositionally different from the other liner layer. In an embodiment of more than three layers, the film comprises at least one layer other than a core or liner film layer.

Detailed description of the invention

Definitions

Unless otherwise stated, implied from context, or customary in the art, all parts and percentages are based on weight and all test methods are current as of the date of presentation of this description. For purposes of United States patent practice, the contents of any referenced patent, patent application or publication are incorporated by reference in their entirety (or its equivalent US version is thus incorporated by

<img file="MX350481B_D0008.tif" />

⁸ IMPI

B »fflTUTe MUKANC 'Μ IA FkUrUBA ·' wwim reference) especially with respect to the description of the definitions (insofar as it is not incompatible with any definition specifically provided in this description) and general knowledge in the matter.

The numerical ranges in this description are approximate, and consequently may include values ​​outside the range unless otherwise indicated. Numeric ranges include all values ​​from and including the lower and upper values, in increments of one unit, since there is a separation of at least two units between any lower value and any higher value. As an example, if a compositional, physical, or other property, such as, for example, molecular weight, etc., ranges between 100 and 1000, all individual values, such as, 100, 101, 102, are intended to etc., and subranges, such as 100 to 144, 155 to 170, 197 to 200, etc. are expressly listed. For ranges that contain values ​​that are less than one or that contain fractional numbers greater than one (for example, 1.1, 1.5, etc.), a unit is considered to be 0.0001, 0.001, 0.01, or 0.1, as appropriate. For ranges containing single-digit numbers less than ten (for example, 1 to 5), one unit is typically considered to be 0.1. These are only examples of what is specifically intended, and all possible combinations of numerical values ​​between the lowest value and the highest value listed should be considered expressly stated in this description. Numerical ranges are provided in this description, among other things, for proportional amounts of

- 9 IMPI

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<img file="MX350481B_D0009.tif" />

the core and liner layers and the proportional amounts of various resins in one layer.

Multilayer film and like terms refer to a film comprising two or more layers of film. Each film layer can be the same or different in composition and thickness.

Facial surface and similar terms are used in distinction to edge surface. For example, if it has a rectangular shape or configuration, a layer, for example film, will comprise two opposite face surfaces joined by four edge surfaces (two opposite pairs of edge surfaces, each pair intersecting the other pair at right angles ). If it has a circular configuration, then the layer will comprise two opposing face surfaces joined by a continuous edge surface.

Composition and like terms refer to a mixture or combination of two or more components.

Polymer blend and like terms mean a blend of two or more polymers. Such a mixture may or may not be miscible. Such a mixture may or may not have phase separation. Such a mixture may or may not contain one or more domain configurations, as determined from transmission electron spectroscopy, light scattering, X-ray scattering, and any other method known in the art.

The term "polymer" (and like terms) is a macromolecular compound prepared by reacting (ie, polymerizing) monomers of the same or different type. Polymer includes homopolymers and interpolymers.

<img file="MX350481B_D0010.tif" />

Interpolymer refers to a polymer prepared by the polymerization of at least two different monomers. This generic term includes copolymers, generally used to refer to polymers made from two different monomers and polymers made from more than two different monomers, eg, terpolymers, tetrapolymers, etc.

Polyolefin, olefin-based polymer, and like terms refer to a polymer that contains, in polymerized form, a majority weight percent of an olefin, eg, ethylene or propylene, based on the total weight of the polymer. Non-limiting examples of olefin-based polymers include ethylene-based polymers and propylene-based polymers.

Rich in ULDPE and like terms refer to a formulation, film layer, etc., it comprises more than 50% by weight of ULDPE.

Crystalline and similar terms as applied to a polymer refer to a polymer or segment of a polymer that possesses a first-order transition or crystalline melting point (Tm) as determined by Differential Scanning Calorimetry (DSC). English) or equivalent technique. The term can be used interchangeably with the term semi-crystalline. Crystals can exist as stacks of tightly packed laminar crystals, lamellae that form spherulite arms, or as isolated laminar or fringed micellar crystals.

Amorphous and like terms as applied to a polymer are

<img file="MX350481B_D0011.tif" />

- 11 refer to a polymer that lacks a crystalline melting point as determined by DSC or equivalent technique.

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ULDPE

These thermoplastic polymers are ethylene / olefin interpolymers. Typically, the α-olefin is one or more, preferably one, of a linear branched or cyclic α-olefin with a molecule of 3 to 20 carbon atoms. Examples of α-olefins with a molecule of 3 to 20 carbon atoms include propene, 1-butene, 4-methyl-1-pentene, ΙΙΟ hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1 hexadecene and 1-octadecene. The α-olefins can also contain a cyclic structure such as cyclohexane or cyclopentane, which results in an α-olefin such as 3-cyclohexyl-1-propene (aillo cyclohexane) and vinyl cyclohexane. Although they are not α-olefins in the classical sense of the term, for the purposes of this invention certain cyclic definitions, such as norbornene and related olefins, are aolefins and can be used in place of some or all of the α-olefins described above. Illustrative polyolefin copolymers include ethylene / propylene, ethylene / butene, ethylene / 1-hexene, ethylene / octene 120, ethylene / styrene, and the like. Illustrative terpolymers include ethylene / propylene / 1-octene, ethylene / propylene / butene, ethylene / butene / 1-octene, and ethylene / butene / styrene.

The ULDPE used in the practice of this invention has a density as measured by ASTM D792 of 0.900 to 0.920, typically 0.903 to 0.915, and even more typically 0.903 to 0.913

- 12 g / cc.

<img file="MX350481B_D0012.tif" />

Specific examples of ULDPE useful in this invention include ATTANE® 4606G, 4647G, SL 4100G, SL 4101 G, and SL 4102G;

DOWLEX ® 2103, 2045, 5056 and 4056; and AFFINITY® 1880 ethylene / 1-octene or ethylene / 1-hexene copolymers made by The Dow Chemical Company).

LDPE

The LDPE used in the practice of this invention can be made by known processes, or it can be obtained commercially. LDPE is manufactured using a high pressure free radical polymerization process. Alternatively, LDPE suitable for use in the practice of the present invention can be obtained commercially from various manufacturers. For example, him

LDPE is available from The Dow Chemical Company as DOW® LDPE 150E, 303, 310, 421, 515, 535, and many other grades, and from LyondelIBasell Industries under the trade names LUPOLEN® and PETROTHENE®. LDPE suitable for use in this invention typically has an MI (Melt Index, ASTM D1238, Condition

190 / 2.16) from 4 to 15 grams per 10 minutes (g / 10 min) and a density of

0.915-0.925 g / cc (ASTM D792 standard).

EVE

Ethylene vinyl acetate is a well-known polymer and is readily available commercially, for example, resin resins.

EVA ELVAX® available from DuPont. The vinyl acetate content of the EVA resins used in the practice of this invention can

<img file="MX350481B_D0013.tif" />

vary widely, but typically the minimum content of vinyl acetate is at least 5% by weight. The maximum vinyl acetate content of the EVA resins used in the practice of this invention can also vary greatly, but is typically no more than 20% by weight.

Core layer

The core layer or layers of the multilayer stretch cover packaging film of this invention comprise a majority of ULDPE and optionally a minority of one or more LDPE and EVA. In one embodiment, the core layer comprises 100% by weight ULDPE. In one embodiment, the core layer comprises 90, 75 or 50% by weight or more of ULDPE with one or more of LDPE and EVA comprising no more than 50, typically no more than 25, and even more typically no more than 10%. by weight of the layer. In one embodiment, the core layer, or each core layer, if it has more than one, comprises at least 50% by weight ULDPE with a density of 0.900 to 0.920 g / cc, and optionally at least one of between an LDPE with a density of 0.915 to 0.925 g / cc and EVA with a VA content of 5 to 20% by weight.

The core layers of the stretch cover films of this invention do not always need to be positioned as an inner layer of the film. As non-limiting examples, if the movie of

<img file="MX350481B_D0014.tif" />

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OF THE INDUmUAL ΕΒΟΗΖΟλο stretch cover is a monolayer or two-layer film, then the core film layer will necessarily constitute an outer layer of the stretch cover film.

Lining layers

The liner layers of the multilayer stretch cover packaging film of this present invention also comprise a majority of ULDPE and optionally a minority of LDPE. In one embodiment, either or both liner layers comprise 100% by weight ULDPE. In one embodiment, either or both liner layers comprise 90, 75, or 50% by weight or more of ULDPE, with the LDPE comprising no more than 50, typically no more than 25, and even more typically no more than 10% by weight of either layer or both. In one embodiment, each liner layer comprises at least 50% by weight of ULDPE with a density of 0.900 to 0.920 g / cc, and optionally LDPE with a density of 0.915 to 0.925 g / cc. The composition of one lining layer may be the same or different from the composition of the other lining layer.

The liner layers of the stretch cover films of this invention do not always need to be laid as an outer layer of the film. As a non-limiting example, if the stretch cover film is a multilayer film comprising one or more layers other than a core or liner layer, for example, a moisture or oxygen barrier film layer such as a layer that comprises polyvinylidene chloride or ethylene vinyl alcohol,

<img file="MX350481B_D0015.tif" />

Thereafter, the barrier film layer can be laid as an outer or outer layer. Preferably, the liner film layers of this invention are located on the stretch cover film as outer layers.

Film layers other than core and liner layers

In one embodiment of the invention, a multilayer stretch cover packaging film comprises at least one of a core and liner layer as described above and one or more additional film layers. These additional film layers are incorporated for various purposes, eg, water and / or oxygen barriers, mechanical strength, chemical resistance, etc., and are typically incorporated as an inner layer of the packaging film. These layers, if present, are used in known ways and in known amounts.

Multilayer Stretch Covers Packaging Film

The films of this invention comprise at least one core layer and optionally two skin layers. In a three-layer film (A / B / C), one face surface of a liner layer (A) is in direct contact with one face surface of the core layer (B), while the other face surface of the core layer (B) is in direct contact with a face surface of the other lining layer (C). The liner layers A and C can be the same or different. In these three-layer film structures, the layer of

<img file="MX350481B_D0016.tif" />

IMPI

INSTTTUTC MBUCANQ DI LA PROPICIAD INDUSTRIA!

core typically comprises 50% by weight or more of the entire film, and the weight of the combined liner layers is less than 50% by weight of the entire film, typically with each liner layer comprising the same weight percent of all the film, for example, if the core layer comprises 60% by weight of the film, then each liner layer comprises 20% by weight of the film (although each liner layer may comprise a different weight percent of the film, for example, 25 and 15% by weight).

The layers can be sandwiched between the core and liner layers for any number of reasons, eg, performance, economy, etc. In one embodiment, the film structure comprises

5, 7 or more layers. Although these alternative constructions comprise only two skin layers, they can comprise more than one core layer. For example, a five-layer film structure may comprise a central core layer in contact with two opposing adhesive layers each of which is in direct contact with a liner layer, for example A / D / C / D / C with the adhesive layer designated as D. The two liner layers can be the same or different and the two adhesive layers can be the same or different. In an alternative five-layer construction, each of the layers in contact with the liner layers is a core layer each of which is in contact with a central separation layer, for example, A / B / D / B / C with the center layer designated as D. Here too, each lining layer (A, C) can be the same or different, and each core layer (B) can be the same or different. In each of these

- 17IMPI ΟΜΤΓΠβν MUUCANO ^r DfU «ΟΗ» · ΛΙ&gt; '^ ΙΝΓΗΙΤΤ.ίΑΕ ____ constructions comprising more than three layers, the core layer, or

<img file="MX350481B_D0017.tif" />

a combination of core layers, if you have more than one, ^lBm^TIt is at least 50% by weight of the weight of the film.

The density of the film, unlike the density of the individual layers, is not greater than 0.920, typically not greater than 0.917, and still more typically not greater than 0.912, g / cc. The average density of a given piece of film can be measured by first cutting the film using a knife or scissors into small pieces or strips in the range of a few millimeters in size, typically close to the size of raw material tablets, for example, from 5 to 10 mm. These pieces of film are then compression molded into plates of length-by-width-by-thickness dimensions of 32 by 32 by 2 millimeters in accordance with the international standards ISO 293 and ISO 187. The plates are cut using an appropriately sized knife and the Density is measured using the procedure in ASTM D792-08. Isopropanol is used as the liquid for the Archimedean method. Three samples are taken for an average density reading in g / cm³. Annealing density is measured between 48 and 80 hours after plate casting. Rapid density reading is measured between 15 minutes and 1 hour after plate casting.

The thickness of the films is 50 to 200, preferably 70 to

140 microns (pm), and thickness is typically determined by the intended use and properties of the film. The thickness of each film layer is typically no more than 30 to 80 percent of the total film thickness, and the thickness of the core layer is typically greater.

- 18 than any layer of lining.

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Each layer of the film may comprise nwc iQimmacu&gt; additifnft and / or fillers such as, but not limited to, anti-blocking or slip agents, bonding agents, antioxidants, colorants, UV stabilizers, processing and the like. These additives and fillers are used in known amounts and in known ways.

The films are made by known methods, eg, coextrusion or lamination, and are used in known applications.

Representative stretch cover packaging films include, but are not limited to,

A. A monolayer film comprising 100 to 50% by weight of ULDPE with a density of 0.900-0.920 g / cc and 0 to 50% by weight of at least one of LDPE with a density of 0.915-0.925 g / cc Y

EVA comprising 5-20% by weight of vinyl acetate; Y

B. A three-layer film comprising:

1. Two layers of lining each of which comprises:

to. 10-25% by weight of the film, and

b. 100 to 50% by weight of ULDPE with a density of 0.900-0.920 g / cc, and 0 to 50% by weight of LDPE with a density of 0.915-0.925 g / cc, and

two. A core layer comprising:

to. 80-50% by weight of the film, and

b. 100 to 50% by weight of ULDPE with a density

<img file="MX350481B_D0019.tif" />

C.

0.900-0.920 g / cc, and 0 to 50% by weight of LDPE with a density of 0.915-0.925 g / cc; Y

A three-layer film comprising:

1. Two layers of lining each comprising:

to. 10-25% by weight of the film, and

b. 100 to 50% by weight of ULDPE with a density of 0.905 g / cc, and 0 to 50% by weight of LDPE with a density of 0.915-0.925 g / cc,

two. A core layer comprising:

to. 80-50% by weight of the film, and

b. 100 to 50% by weight of ULDPE with a density of 0.905 g / cc and 0 to 50% by weight of EVA with 520% ​​by weight of vinyl acetate;

A five-layer film comprising:

1. Two layers of lining each comprising:

to. 10-25% by weight of the film, and

b. 100 to 50% by weight of ULDPE with a density of 0.900-0.920 g / cc, and 0 to 50% by weight of LDPE with a density of 0.915-0.925 g / cc, and

two. Two layers of lining each comprising:

to. 10-25% by weight of the film, and

b. 100 to 50% by weight of ULDPE with a density of 0.900-0.920 g / cc, and 0 to 50% by weight of LDPE with a density of 0.915-0.925 g / cc, and

3. A core layer comprising:

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b. 100 to 50% by weight of ULDPE with a density of 0.900-0.920 g / cc, and 0 to 50% by weight of

LDPE with a density of 0.915-0.925 g / cc;

F. A five layer film comprising:

1. Two layers of lining each comprising:

to. 10-25% by weight of the film, and

b. 100 to 50% by weight of ULDPE with a density of 0.900-0.920 g / cc, and 0 to 50% by weight of at least one of LDPE with a density of 0.915-0.925 g / cc, and EVA comprising 520 weight% vinyl acetate;

two. Two core layers each comprising:

to. 10-25% by weight of the film, and

b. 100 to 50% by weight of ULDPE with a density of 0.900-0.920 g / cc, and 0 to 50% by weight of at least one of LDPE with a density of 0.915-0.925 g / cc, and EVA comprising 520 weight% vinyl acetate;

3. A core layer comprising:

to. 70-25% by weight of the film, and

b. 100 to 50% by weight of ULDPE with a density of 0.900-0.920 g / cc, and 0 to 50% by weight of at least one of LDPE with a density of 0.915-0.925 g / cc, and EVA comprising 5 - 21 IMPI ΐΝΓτηυτο m * icab®

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20% by weight of vinyl acetate;

G. A polymeric mono- or multilayer stretch cover packaging film with a total density not exceeding 0.915 g / cc and comprising:

1. At least one core layer comprising:

to. At least 50% by weight of ULDPE with a density of 0.900 to 0.920 g / cc; Y

b. Optionally at least one of:

i. LDPE with a density of 0.915 to 0.925 g / cc, and ii. EVA with a VA content of 4 to 20% by weight; Y

two. Optionally, two lining layers, each lining layer independently comprises:

to. At least 50% by weight of ULDPE with a density of 0.900 to 0.920 g / cc; Y

b. Optionally an LDPE with a density of 0.915 to 0.925 g / cc; Y

H. A polymeric multilayer stretch cover packaging film with a total density not exceeding 0.915 g / cc and comprising:

1. At least one core layer comprising:

to. At least 50% by weight of ULDPE each with a density of 0.900 to 0.920 g / cc; Y

b. Optionally at least one of:

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LDPE with a density of 0.915 to 0.925

<img file="MX350481B_D0020.tif" />

g / cc, and ii. EVA with a VA content of 4 to 20% by weight; Y

two. Two lining layers, each lining layer independently comprises:

to. At least 50% by weight of ULDPE each with a density of 0.900 to 0.920 g / cc; Y

b. Optionally an LDPE with a density of

0.915 to 0.925 g / cc.

SPECIFIC MODALITIES

Performance screening of key resins

Selected EVA resins with a typical VA level between 5 and 18% by weight and as known in the market for the production of commercial stretch cover film structures are used as benchmark performance grades. Typically such resins are used in the core layer (s) of typically films of 3 to 5 or more coextruded layers at total film composition levels typically above 30 and even more typically at levels above 50 % in weigh:

- Resin A: GREENFLEX® FD20 EVA copolymer with 5% by weight of VA, Ml₂ 0.5 g / 10 min (ASTM D1238 standard)

- Resin B: NEXXSTAR * 00111 EVA copolymer with 7.5% by weight of VA, Ml₂ 0.5 g / 10 min

-23- Resin C: GREENFLEX® FF45

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<img file="MX350481B_D0021.tif" />

by weight of VA, Ml₂ 0.7 g / 10 min (rule 13011 99) ' ¹^{1 r}

- Resin D: GREENFLEX ® FD53 EVA copolymer with 17% by weight of VA, Ml₂ 0.47 g / 10 min (ASTM D1238) to compare to these ULDPE grades:

- Resin E: ATTANE SL 4100G ultra low density octene PE copolymer with a density of 0.912 g / cc and Ml₂ 1.0 g / 10 min

- Resin F: ATTANE SL 4102G ultra low density octene PE copolymer with a density of 0.905 g / cc and Ml₂ 1.0 g / 10 min.

GREENFLEX® is a registered trademark of POLIMERI EUROPA NEXXSTAR * is a registered trademark of ExxonMobil Chemical The monolayer film structures of all these resins are produced on a Dr. Collin coextrusion blown film line with a standard 30mm single screw extruder mm diameter and a 60mm diameter monolayer die:

<td>Film thickness monolayer</td><td>60 pm</td>

<td>Output monolayer</td><td>7 kg / h</td>

<td>Blowing ratio</td><td> 3 : 1</td>

<td>Die diameter</td><td>60 mm</td>

<td>Die opening</td><td>1.2 mm</td>

<td>Frost line height</td><td>~ 200 mm</td>

<td>Melting temperatures</td><td>~ 210 ° C</td>

Since the resins used in these examples have a relatively low degree of crystallinity, some of the films develop quite different blocking effects during manufacture. Anti-lock additives are not added to film formulations. In cases where, after the collapse of a bubble, it is not possible to separate the layers, the problem is solved by collapsing the 30 µm thick wall films and introducing separation sheets into the winder.

The determination of the elastic recovery levels is a key criterion to describe the performance of packaging machines under laboratory conditions. Data can be generated according to the conventional test of ASTM D5459-95. Measurements are made at 50% voltage levels. Test details: A 127 * 15mm specimen is cut from the film in the cross direction and placed between the clamps 127mm apart. The sample is stretched at a speed of 127 mm / min to 50% final tension and held there for 60 seconds to relax. Subsequently, the crosshead returns to the original clamp spacing and the specimen was held there at 0% tension for another 180 sec relaxation period before the second elongation cycle began. Elastic recovery values ​​can then be determined as described in the test standard.The data for the selected resins and the films made from them are measured in the cross-film direction and show a comparable performance range:

- Resin A: 88.5%

- Resin B: 89.1%

- Resin C: 89.4%

- Resin D: 89.9%

- Resin E: 87.9%

- Resin F: 89.2%

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<img file="MX350481B_D0022.tif" />

In addition to the elastic recovery values, these other film parameters are chosen to describe key packaging performance key behavior:

• Dart Throwing Impact - Method A: ISO 7765-1 • Elmendorf Tear Propagation (Cross Direction = CD) and Machine Direction = MD: Standard ASTM D792 • Puncture resistance: ASTM D-5748 standard

The impact values ​​per launch of selected resin darts and the films made from them:

- Resin A: 454 g

- Resin B: 697 g

- Resin C: 1 056 g

- Resin D: 1086 g

- Resin E: 1679 g

- Resin F: greater than 2500 g

The Elmendorf tear propagation values ​​(CD / MD) of selected resins and films made from the

-26same:

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- Resin A: 158/102 g —-..... ..&gt; ~

- Resin B: 98/62 g

- Resin C: 11 3/73 g

- Resin D: 11 8/74 g

- Resin E: 1340/1180 g

- Resin F: 1 140/1070 g

The puncture resistance of selected resins and films made from them:

- Resin A: 6.4 J / cm³

- Resin B: 7.7 J / cm³

- Resin C: 14.5J / cm

- Resin D: 17.5J / cm

- Resin E: 10.6J / cm

- Resin F: 15.8J / cm

Benchmarking Industrial Film Structures

The three-layer coextruded film structures are produced on a Hosokawa Alpine extrusion line. The configuration of the extrusion line:

- Extruders: 2 * 65 (position of liner layers A and C) + 1 * 90 (position of core layer B) / mm, all L / D 30 ratio

Die: 300 (diameter) * 1.5 (opening) / mm

- Melting temperatures: approximately 220 ° C

- Bubble cooling: raised single air ring, IBC

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- Drag: lateral reinforcements up to 400 mm * iNourr £ u £

- Output rate: total = 350 kg / h; 2 * 70 kg / κ. for lining and 210 kg / h for the core layer

- Film thickness: 100 microns

- Layer distribution: ABC = 20-60-20%

Additional resins used:

- Resin G: ESCORENE * FL 00014 EVA copolymer with 14% by weight of VA, Ml₂ 0.25 g / 10 min

- Resin H: ESCORENE * FL 00218 EVA copolymer with 18% by weight of VA, Ml₂ 1.7 g / 10 min * ESCORENE is a registered trademark of ExxonMobil Chemical

- Resin I: Dow LDPE 150E PE low density with D of 0 920 g / cc and Ml₂ 0.25 g / 10 min

- Resin K. DOWLEX SL 2103 low linear density octene PE copolymer with a density of 0.917 g / cc and Ml₂ of 0 7 g / 10 min.

- Resin L: VERSIFY 2300 ethylene-propylene elastomer with a density of 0.8665 g / cc and Ml₂ 2.0 (230C) Film Design Parameters:

- All films: ABC = Layer division 20-60-20%

- Movie 1: 1.1 (comparative)

- Liner layers A = C: K resin mix (79%) + Resin I (17%) + master mixes (3% antiblock% + 1% processing aid)

- Core layer B: Resin G

<img file="MX350481B_D0024.tif" />

<img file="MX350481B_D0025.tif" />

- Movie: 1.2 (comparative)

- Lining layers A = C: mixture of resirrarit- ^ g ^ j I · (17%) + Masterbatches (3% antiblocking + 1% processing aid)

- Core layer B: Resin H

- Inventive 1: 2.2 movie ⁰ Liner layers A = C: K resin blend (79%) + Resin I (16%) + Masterbatches (3% antiblocking + 1% slip + 1% processing aid) ⁰ Core layer B: mixture of resin F (70%) and resin L (30%)

- Inventive Movie 2: 3.1 ⁰ Liner layers A = C: resin blend F (79%) + Resin I (17%) + masterbatches (3% antiblock + 1% processing aid) ⁰ Core layer B: mixture of resin F (70%) and resin L (30%)

- Inventive Film 3: 4.2 ° Liner Layers A = C: resin blend F (79%) + resin I (17%) + masterbatches (3% antiblock + 1% process aid) ⁰ Core layer B: mixture of resin F (70%) and resin I (30%)

Key properties of all specified film structures:

Elastic recovery on MD and CD:

⁰ Comparative Film 1: 73.8 / 76.5%

- 29th Comparison Film 74.5 / 76.2% ° Inventive Film 1: 67.8 / 70.1% ⁰ Inventive Movie 2: 2: 73.8 / 75.5% ⁰ Inventive Movie 3: 67.1 / 70.4

<img file="MX350481B_D0026.tif" />

Dart Throw Impact - Important Note = Long Dart Type B:

⁰ Comparative Film 1: 1452g ⁰ Comparative Film 2: 1194g ⁰ Inventive Film 1. 1905 g ° Inventive Film 2: 2384 g ⁰ Inventive Film 3: 1212g

Elmendorf tear propagation (in MD and CD):

o Comparative film 1: 1050/1740 g ⁰ Comparative Film 2: 532/836 g ⁰ Inventive Film 1: 1390/2160 g ⁰ Inventive Film 2: 1380/1990 g ⁰ Inventive Film 3: 1240/1830 g

Puncture resistance - elongation:

⁰ Comparison Film 1: 91mm ⁰ Comparison Film 2: 92mm ° Inventive Film 1: 99mm ⁰ Inventive Film 2: 160mm ⁰ Inventive Film 3: 133mm

Although the invention has been described in some detail through the preceding description of the preferred embodiments, this detail is

- 30 IMPI

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IMMimiAL for the primary purpose of illustration. The person skilled in the art can make many variations and modifications * without isolating himself from the spirit and scope of the invention as described in the following claims.

<img file="MX350481B_D0028.tif" />

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