Multilayer film having at least one matte surface

Abstract

Embodiments of the present invention relate to multilayer films, labels, and packaging. In one aspect, a multilayer film having at least one matte surface includes (a) an outer layer comprising (i) 30 wt.% to 99.5 wt.% of a first low density polyethylene having a density of 0.919 g / cm 3 to 0.940 g / cm 3 and a melt index (I2) of 0.3 g / 10 min to 5 g / 10 min, (ii) 0.1 wt.% to 20 wt.% of polymer particles having a core and a shell structure, wherein the core comprises a first polymeric material having a first refractive index and the shell comprises a second polymeric material having a second refractive index different from the first refractive index, and (iii) optionally, up to 50 wt.% of a first polyethylene having a density of 0.925 g / cm 3 to 0.970 g / cm 3 and a melt index (I2) of 0.8 g / 10 min to 10 g / 10 min, each based on the total weight of the outer layer; and (b) a second layer in adhering contact with the outer layer, the second layer comprising (i) 1 wt.% to 80 wt.% of a second low density polyethylene having a density of 0.919 g / cm 3 to 0.940 g / cm 3 and a melt index (I2) of 0.3 g / 10 min to 5 g / 10 min, and (ii) 20 wt.% to 99 wt.% of a second polyethylene having a density of 0.925 g / cm 3 to 0.970 g / cm 3 and a melt index (I2) of 0.8 g / 10 min to 10 g / 10 min, each based on the total weight of the second layer; wherein the outer layer has a glossiness of less than 50% measured by ASTM D2457 at a 45° angle.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to multilayer films having at least one matte surface, and to articles, such as labels and packaging, comprising multilayer films having at least one matte surface. BACKGROUND

[0002] Polymeric films having matte surfaces are often used in a variety of applications. Optical properties, such as matte surfaces, can be defined in terms of surface gloss and haze. Matte surfaces can be characterized by lower gloss and higher haze values as discussed further herein.

[0003] Packaging applications, such as bags and pouches for pet food, snack foods, and the like, sometimes utilize polymeric films having matte surfaces. Matte surfaces can be obtained by blending of incompatible polyolefins, often by using a blend of polyethylene and polypropylene. However, these incompatible polyethylene and polypropylene blends present process control issues. Specifically, when different machine programs are used to blend the incompatible polyolefins, the properties of the film product can be unpredictable and inconsistent.

[0004] There is also interest in polyethylene films having matte surfaces for use in labels. The development of labels has traditionally focused on improving the homogeneity of the material along with the surface of the product. Traditionally, most glossy labels have been considered professional and high quality. However, the market is changing and the naturally occurring matte finish is becoming more and more important. For example, in some cases, labels having a matte finish have been used to convey information about high quality organic products. A common approach to provide a natural looking surface and a natural appearance is to provide a rough surface. This can be achieved by using inorganic fillers, but can also degrade the mechanical properties of the label.

[0005] There remains a need for new multilayer films having matte surfaces and acceptable mechanical properties that can be used in label and / or packaging applications. SUMMARY

[0006] The present invention provides multilayer films having matte surfaces and, in some embodiments, desirable mechanical properties. In some embodiments, the multilayer films of the present invention have particularly low surface gloss values in the outer layer to provide a matte surface. In some embodiments, the multilayer films of the present invention have particularly low gloss values in the outer surface while maintaining desirable mechanical properties. In addition to providing a desirable appearance for some applications, the multilayer films of the present invention having matte surfaces can also provide other advantages in some embodiments, such as reduced blocking and / or potentially improved adhesion in lamination.

[0007] In one aspect, the present application provides a multilayer film having at least one matte surface, the multilayer film comprising (a) an outer layer comprising (i) from 30 wt% to 99.5 wt% of a first low density polyethylene having a density from 0.919 g / cm 3 to 0.940 g / cm 3 and a melt index (I2) from 0.3 g / 10 min to 5 g / 10 min, (ii) from 0.1 wt% to 20 wt% of polymer particles having a core and a shell structure, wherein the core comprises a first polymeric material having a first refractive index and the shell comprises a second polymeric material having a second refractive index different from the first refractive index, and (iii) optionally, up to 50 wt% of a first polyethylene having a density from 0.925 g / cm 3 to 0.970 g / cm 3 and a melt index (I2) from 0.8 g / 10 min to 10 g / 10 min, each based on the total weight of the outer layer; and (b) a second layer in adhering contact with the outer layer, the second layer comprising (i) from 1 wt% to 80 wt% of a second low density polyethylene having a density from 0.919 g / cm 3 to 0.940 g / cm 3 and a melt index (I2) from 0.3 g / 10 min to 5 g / 10 min, and (ii) from 20 wt% to 99 wt% of a second polyethylene having a density from 0.925 g / cm 3 to 0.970 g / cm 3 and a melt index (I2) from 0.8 g / 10 min to 10 g / 10 min, each based on the total weight of the second layer; wherein the outer layer has a gloss, measured by ASTM D2457 at a 45° angle, of less than 50%.

[0008] As discussed below, the present application also provides articles, such as labels and packaging, formed from any of the inventive multilayer films disclosed herein.

[0009] These and other embodiments are described in greater detail in the DETAILED DESCRIPTION. DETAILED DESCRIPTION

[0010] Unless otherwise stated, implied or custom in the art, all parts and percentages are by weight, all temperatures are in °C, and all test methods are current methods as of the filing date of this disclosure.

[0011] The term "composition," as used herein, refers to a mixture of materials which comprises the composition, as well as reaction products and decomposition products formed from the materials of the composition.

[0012] "Polymer" means a polymeric compound prepared by polymerizing monomers, whether of the same or a different type. The generic term polymer thus encompasses the term homopolymer, as defined below, and the term interpolymer, as defined below. Trace impurities (e.g., catalyst residues) can be incorporated into and / or within the polymer. The polymer can be a single polymer, a polymer blend, or a polymer mixture, including mixtures of polymers formed in situ during polymerization.

[0013] As used herein, the term "interpolymer" means a polymer prepared by polymerizing at least two different types of monomers. The generic term interpolymer thus includes copolymers, which are polymers prepared from two different types of monomers, and polymers prepared from more than two different types of monomers.

[0014] As used herein, the term "olefin-based polymer" or "polyolefin" means a polymer that includes a major amount of an olefin monomer, such as ethylene or propylene, in polymerized form (by weight of the polymer) and optionally can include one or more comonomers.

[0015] As used herein, the term "ethylene / alpha-olefin interpolymer" means an interpolymer that includes a major amount (> 50 mol%) of units derived from ethylene monomer and the remaining units derived from one or more alpha-olefins. Typical alpha-olefins used to form ethylene / alpha-olefin interpolymers are C3-C 10 olefins.

[0016] As used herein, the term "ethylene / alpha-olefin copolymer" means a copolymer that includes a major amount (> 50 mol%) of ethylene monomer and alpha-olefin as the only two types of monomers in polymerized form.

[0017] As used herein, the term "alpha-olefin" means an olefin having a double bond at the primary or alpha position.

[0018] "Polyethylene" or "ethylene-based polymer" shall mean a polymer that includes a major amount (> 50 mol%) of units derived from ethylene monomer. This includes polyethylene homopolymers, ethylene / alpha-olefin interpolymers, and ethylene / alpha-olefin copolymers. Common forms of polyethylene known in the art include low density polyethylene (LDPE); linear low density polyethylene (LLDPE); ultra low density polyethylene (ULDPE); very low density polyethylene (VLDPE); medium density polyethylene (MDPE); high density polyethylene (HDPE); reinforced polyethylene; polyethylene elastomers; and polyethylene plastomers. These polyethylene materials are generally known in the art; however, the following description can be helpful in understanding the differences between some of these different polyethylene resins.

[0019] The term "LDPE" can also be referred to as "high pressure ethylene polymer" or "highly branched polyethylene" and is defined to mean that the polymer is partially or entirely homopolymerized or copolymerized in autoclave or tubular reactors at pressures higher than 14,500 psi (100 MPa) using free-radical initiators such as peroxides (see, for example, US 4,599,392, which is hereby incorporated by reference). LDPE resins typically have densities in the range of 0.916 g / cm3to 0.935 g / cm3. 3 3

[0020] The term "LLDPE" includes both resins made using traditional Ziegler-Natta catalyst systems and chromium-based catalyst systems as well as single-site catalysts including, but not limited to, bis-metallocene catalysts (sometimes referred to as "m-LLDPE"), constrained geometry catalysts (CGC), and molecular catalysts. The resins include linear, substantially linear, or heterogeneous polyethylene-based copolymers or homopolymers. LLDPE includes less long chain branching than LDPE and comprises substantially linear ethylene polymers, which are further defined in U.S. Patent 5,272,236, U.S. Patent 5,278,272, U.S. Patent 5,582,923, and U.S. Patent 5,733,155; homogeneously branched linear ethylene polymer compositions such as those in U.S. Patent No. 3,645,992; heterogeneously branched ethylene polymers such as those made according to the process disclosed in U.S. Patent No. 4,076,698; and / or blends thereof (such as those disclosed in US 3,914,342 or US 5,854,045). LLDPE can be made by gas-phase, solution-phase, or slurry polymerization, or any combination thereof, using any type of reactor or reactor configuration known in the art.

[0021] ​​The term "MDPE" means a polyethylene having a density from 0.926 g / cm 3 to 0.940 g / cm 3 "MDPE" is typically made using a chromium or a Ziegler-Natta catalyst or using a single-site catalyst, including but not limited to, bis-metallocene catalysts, constrained geometry catalysts, and molecular catalysts, and has a molecular weight distribution ("MWD") typically greater than 2.5.

[0022] The term "HDPE" means a polyethylene having a density greater than about 0.940 g / cm 3 and up to about 0.970 g / cm 3 HDPE is generally made with a Ziegler-Natta catalyst, a chromium catalyst, or a single-site catalyst, including but not limited to, bis-metallocene catalysts, and constrained geometry catalysts.

[0023] The term "ULDPE" means a polyethylene having a density from 0.880 g / cm 3 to 0.912 g / cm 3 ULDPE is generally made with a Ziegler-Natta catalyst, a chromium catalyst, or a single-site catalyst, including but not limited to, bis-metallocene catalysts, and constrained geometry catalysts.

[0024] A "polyethylene plastomer / elastomer" is a substantially linear or linear ethylene / alpha-olefin copolymer containing a homogeneous short chain branching distribution including units derived from ethylene and units derived from at least one C3-C 10 alpha-olefin comonomer, or at least one C4-C8 alpha-olefin comonomer, or at least one C6-C8 alpha-olefin comonomer. The polyethylene plastomer / elastomer has a density from 0.870 g / cm 3 , or 0.880 g / cm 3 , or 0.890 g / cm 3 to 0.900 g / cm 3 , or 0.902 g / cm 3 , or 0.904 g / cm 3 , or 0.909 g / cm 3 , or 0.910 g / cm 3 , or 0.917 g / cm 3 The non-limiting examples of polyethylene plastomers / elastomers include AFFINITY TM plastomers and elastomers (available from The Dow Chemical Company), EXACT plastomers (available from ExxonMobil Chemical), Tafmer (available from Mitsui), Nexlene TMLucene (available from LG Chem Ltd.).

[0025] The terms "blend," "polymer blend," and the like mean a composition of two or more polymers. Such a blend can or can not be miscible. Such a blend can or can not be phase separated. Such a blend can or can not contain one or more domain configurations as determined by transmission electron spectroscopy, light scattering, x-ray scattering, and any other methods known in the art. A blend is not a laminate, but one or more layers of a laminate can contain a blend. Such a blend can be prepared as a dry blend, formed in situ (e.g., in a reactor), a melt blend, or using other techniques known to one skilled in the art.

[0026] The terms "adhering contact" and like terms mean that one surface of one layer is in touching and adhering contact with one surface of another layer such that one layer cannot be removed from the other layer without damaging the interfacial surface (i.e., the contact surface) of both layers.

[0027] The terms "comprising," "including," "having," and their derivatives, are not intended to exclude any additional component, step or procedure, whether or not the same is specifically disclosed. In order to avoid any doubt, all compositions claimed through the use of the term "comprising" can include any additional additive, adjuvant, or compound, whether polymeric or otherwise, that is not specifically delineated. Conversely, the term "consisting essentially of" excludes from the range of equivalents any additional component, step or procedure that is not specifically delineated, except for those that do not materially affect the basic and novel characteristic(s) of the compositions or methods. The term "consisting of excludes any element, step, or procedure not specifically delineated or listed.

[0028] The present invention relates to multilayer films having at least one matte surface and labels and packages formed from such multilayer films. The matte surface can provide a desired appearance, and in some embodiments, the multilayer film can also have desired mechanical properties.

[0029] In one embodiment, the present invention provides a multilayer film having at least one matte surface, the multilayer film comprising (a) an outer layer comprising (i) 30 to 99.5 wt% of a polyolefin having a density of 0.919 g / cm3to 0.940 g / cm3 3 to 0.940 g / cm3 3The following are also present: (i) a first low-density polyethylene with a melt index (I2) of 0.3 g / 10 min to 5 g / 10 min; (ii) 0.1 wt% to 20 wt% of polymer particles having a core and shell structure, wherein the core comprises a first polymer material having a first refractive index and the shell comprises a second polymer material having a second refractive index different from the first refractive index; and (iii) optionally, up to 50 wt% of a density of 0.925 g / cm³. 3 Up to 0.970 g / cm 3 The first polyethylene has a melt flow index (I2) of 0.8 g / 10 min to 10 g / 10 min, each based on the total weight of the outer layer; and (b) a second layer adhered to the outer layer, the second layer comprising (i) 1 wt% to 80 wt% of a polyethylene with a density of 0.919 g / cm³. 3 Up to 0.940 g / cm 3 The second low-density polyethylene has a melt flow index (I2) of 0.3 g / 10 min to 5 g / 10 min, and (ii) 20 wt% to 99 wt% of a material with a density of 0.925 g / cm³. 3 Up to 0.970 g / cm 3 The outer layer contains a second polyethylene with a melt flow index (I2) of 0.8 g / 10 min to 10 g / 10 min, each based on the total weight of the second layer; the outer layer has a gloss of less than 50% as measured by ASTM D2457 at a 45° angle. In some embodiments, the outer layer comprises 80% to 90% by weight of a first low-density polyethylene, based on the weight of the outer layer. In some embodiments, the first low-density polyethylene in the outer layer has a gloss of 0.930 g / cm³. 3 Up to 0.940 g / cm 3 The density and / or melt index (I2) of 2.5 g / 10 min to 4 g / 10 min. In some embodiments, the first polyethylene is present in the outer layer in an amount of up to 50% by weight. In some embodiments, the first polyethylene is present in the outer layer in an amount of up to 20% by weight. In some embodiments, the first polyethylene in the outer layer has a density of 0.60 g / cm³. 3 Up to 0.970 g / cm 3 The density and melt index (I2) of 6 g / 10 min to 10 g / 10 min.

[0030] In some embodiments, the first polymer material of the core of the polymer particle is an elastomer, and the second polymer material of the shell of the polymer particle is thermoplastic. In some embodiments, the shell comprises an acrylic polymer. In some embodiments, the polymer particles have an average size of 1 to 10 micrometers.

[0031] In some embodiments, the outer layer further comprises a compatibilizer. In some embodiments, when present, the compatibilizer is a polyolefin copolymer with acrylic acid, a polyolefin copolymer with an acrylate, a polyolefin copolymer with a maleic anhydride ester, or a polyolefin copolymer grafted with one or more anhydride groups, acrylate groups, or carboxylic acid groups. In some embodiments, the compatibilizer is a maleic anhydride grafted low density polyethylene or a maleic anhydride grafted high density polyethylene. In some embodiments, the compatibilizer is present in the outer layer in an amount of up to 10 wt.%, based on the total weight of the outer layer.

[0032] In some embodiments, the first polyethylene (in the outer layer) and the second polyethylene (in the second layer) are each a high density polyethylene.

[0033] In some embodiments, the multilayer film has two matte surfaces, wherein the multilayer film has a second outer layer, wherein the second layer is between the outer layer and the second outer layer, and wherein the second outer layer has a gloss measured by ASTM D2457 at a 45° angle of less than 50%. In some such embodiments, the second outer layer comprises (i) 30 wt.% to 99.5 wt.% of a low density polyethylene having a density of 0.919 g / cm3to 0.940 g / cm3and a melt index (I2) of 0.3 g / 10 min to 5 g / 10 min, (ii) 0.1 wt.% to 20 wt.% of polymer particles having a core and a shell structure, wherein the core comprises a first polymeric material having a first refractive index and the shell comprises a second polymeric material having a second refractive index different from the first refractive index, and (iii) optionally, up to 50 wt.% of a polyethylene having a density of 0.925 g / cm3to 0.970 g / cm3and a melt index (I2) of 0.8 g / 10 min to 10 g / 10 min, each based on the total weight of the second outer layer. 3 3 In some embodiments, the multilayer film has two matte surfaces, wherein the multilayer film has a second outer layer, wherein the second layer is between the outer layer and the second outer layer, and wherein the second outer layer has a gloss measured by ASTM D2457 at a 45° angle of less than 50%. In some such embodiments, the second outer layer comprises (i) 30 wt.% to 99.5 wt.% of a low density polyethylene having a density of 0.919 g / cm3to 0.940 g / cm3and a melt index (I2) of 0.3 g / 10 min to 5 g / 10 min, (ii) 0.1 wt.% to 20 wt.% of polymer particles having a core and a shell structure, wherein the core comprises a first polymeric material having a first refractive index and the shell comprises a second polymeric material having a second refractive index different from the first refractive index, and (iii) optionally, up to 50 wt.% of a polyethylene having a density of 0.925 g / cm3to 0.970 g / cm3and a melt index (I2) of 0.8 g / 10 min to 10 g / 10 min, each based on the total weight of the second outer layer. 3 3 In some embodiments, the multilayer film has two matte surfaces, wherein the multilayer film has a second outer layer, wherein the second layer is between the outer layer and the second outer layer, and wherein the second outer layer has a gloss measured by ASTM D2457 at a 45° angle of less than 50%. In some such embodiments, the second outer layer comprises (i) 30 wt.% to 99.5 wt.% of a low density polyethylene having a density of 0.919 g / cm3to 0.940 g / cm3and a melt index (I2) of 0.3 g / 10 min to 5 g / 10 min, (ii) 0.1 wt.% to 20 wt.% of polymer particles having a core and a shell structure, wherein the core comprises a first polymeric material having a first refractive index and the shell comprises a second polymeric material having a second refractive index different from the first refractive index, and (iii) optionally, up to 50 wt.% of a polyethylene having a density of 0.925 g / cm3to 0.970 g / cm3and a melt index (I2) of 0.8 g / 10 min to 10 g / 10 min, each based on the total weight of the second outer layer.

[0034] The present disclosure also provides articles, such as labels and packaging, formed from any of the inventive multilayer films disclosed herein.

[0035] outer layer

[0036] ​​The outer layer in the multilayer film advantageously provides a matte surface. As used herein, the term "matte surface" refers to a surface having a dull appearance as opposed to a shiny appearance. A matte surface has one or both of (1) a glossiness of less than 50% and (2) a haze of greater than 45%. In some embodiments, the outer layer has a glossiness of less than 50% as measured by ASTM D2457 at a 45° angle. In some embodiments, the outer layer has a glossiness of less than 45% as measured by ASTM D2457 at a 45° angle. In some embodiments, the outer layer has a haze of greater than 45% as measured by ASTM D1003. In some embodiments, the outer layer has a haze of greater than 50% as measured by ASTM D1003. In some embodiments, the outer layer has a haze of greater than 55% as measured by ASTM D1003.

[0037] To provide a matte surface, the outer layer includes (i) 30 wt% to 99.5 wt% of a first low density polyethylene having a density of 0.919 g / cm 3 to 0.940 g / cm 3 and a melt index (I2) of 0.3 g / 10 min to 5 g / 10 min, and (ii) 0.1 wt% to 20 wt% of polymer particles having a core and a shell structure, wherein the core includes a first polymeric material having a first refractive index and the shell includes a second polymeric material having a second refractive index different from the first refractive index, each based on the total weight of the outer layer. In some embodiments, the outer layer further includes up to 50 wt% of a first polyethylene having a density of 0.925 g / cm 3 to 0.970 g / cm 3 and a melt index (I2) of 0.8 g / 10 min to 10 g / 10 min, based on the total weight of the outer layer. In some embodiments, the outer layer further includes a compatibilizer.

[0038] The outer layer includes a first low density polyethylene having a density of 0.919 g / cm 3 to 0.940 g / cm 3 . All individual values and subranges of 0.919 g / cm 3 to 0.940 g / cm 3 are included herein and disclosed herein; for example, the density of the low density polyethylene can be 0.919 g / cm 3 , 0.920 g / cm 3 , 0.922 g / cm 3 , 0.925 g / cm 3 , 0.927 g / cm 3 , 0.929 g / cm 3 , or 0.930 g / cm 3a lower limit of 0.925 g / cm 3 , 0.930 g / cm 3 , 0.935 g / cm 3 , or 0.940 g / cm 3 to an upper limit of 0.940 g / cm 3 In some embodiments, the low density polyethylene has a density of 0.930 g / cm 3 to 0.940 g / cm 3 .

[0039] In some embodiments, the low density polyethylene has a melt index (I2) of 0.3 g / 10 minutes to 5 g / 10 minutes. All individual values and subranges of 0.3 g / 10 minutes to 5 g / 10 minutes are included herein and disclosed herein. For example, the I2 of the low density polyethylene can have a lower limit of 0.3 g / 10 minutes, 0.5 g / 10 minutes, 0.7 g / 10 minutes, 0.9 g / 10 minutes, 1.0 g / 10 minutes, 1.2 g / 10 minutes, 1.5 g / 10 minutes, 1.8 g / 10 minutes, 2.0 g / 10 minutes, 2.3 g / 10 minutes, 2.5 g / 10 minutes, 2.7 g / 10 minutes, 3.0 g / 10 minutes, 3.3 g / 10 minutes, or 3.5 g / 10 minutes to an upper limit of 2.0 g / 10 minutes, 2.5 g / 10 minutes, 2.8 g / 10 minutes, 3.0 g / 10 minutes, 3.2 g / 10 minutes, 3.5 g / 10 minutes, 3.7 g / 10 minutes, 4.0 g / 10 minutes, 4.2 g / 10 minutes, 4.5 g / 10 minutes, 4.8 g / 10 minutes, or 5 g / 10 minutes. For example, the low density polyethylene can have an I2 of 2.5 g / 10 minutes to 4.0 g / 10 minutes.

[0040] The outer layer comprises 30 wt% to 99.5 wt% of the low density polyethylene, based on the total weight of the outer layer. All individual values and subranges of 30 wt% to 99.5 wt% (wt%) are included herein and disclosed herein; for example, the amount of low density polyethylene can have a lower limit of 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 76 wt%, 80 wt%, 85 wt%, or 90 wt% to an upper limit of 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 75 wt%, 80 wt%, 85 wt%, 90 wt%, 92 wt%, 94 wt%, 96 wt%, 98 wt%, 99 wt%, or 99.5 wt%. For example, the amount of low density polyethylene can be 50 wt% to 95 wt%, or in the alternative, 70 wt% to 95 wt%, or in the alternative, 70 wt% to 90 wt%, or in the alternative, 80 wt% to 90 wt%.

[0041] In some embodiments, examples of low density polyethylene that can be used for the outer layer include DOW LDPE 410E, DOW LDPE 421E, DOW LDPE 515E, DOW LDPE 525E, DOW LDPE 545E, and DOW LDPE 555E, which are commercially available from The Dow Chemical Company. TM Low density polyethylene (LDPE), which is commercially available from The Dow Chemical Company, such as DOW LDPE 410E, DOW LDPE 421E, DOW LDPE 515E, DOW LDPE 525E, DOW LDPE 545E, and DOW LDPE 555E. TM DOW LDPE 410E, DOW LDPE 421E, DOW LDPE 515E, DOW LDPE 525E, DOW LDPE 545E, and DOW LDPE 555E. TM DOW LDPE 410E, DOW LDPE 421E, DOW LDPE 515E, DOW LDPE 525E, DOW LDPE 545E, and DOW LDPE 555E. TM DOW LDPE 410E, DOW LDPE 421E, DOW LDPE 515E, DOW LDPE 525E, DOW LDPE 545E, and DOW LDPE 555E. TM DOW LDPE 410E, DOW LDPE 421E, DOW LDPE 515E, DOW LDPE 525E, DOW LDPE 545E, and DOW LDPE 555E. TM DOW LDPE 410E, DOW LDPE 421E, DOW LDPE 515E, DOW LDPE 525E, DOW LDPE 545E, and DOW LDPE 555E. TM DOW LDPE 410E, DOW LDPE 421E, DOW LDPE 515E, DOW LDPE 525E, DOW LDPE 545E, and DOW LDPE 555E.

[0042] In addition to the LDPE, the outer layer also includes 0.1 wt% to 20 wt% of polymer particles having a core and a shell structure, where the core includes a first polymeric material having a first refractive index and the shell includes a second polymeric material having a second refractive index that is different than the first refractive index.

[0043] The core / shell polymer particles are present in an amount of at least 0.1 wt%, at least 0.5 wt%, or at least 1 wt%, based on the total weight of the outer layer. The core / shell polymer particles are present in an amount of no more than 20 wt%, no more than 15 wt%, no more than 10 wt%, no more than 7 wt%, or no more than 5 wt%, based on the total weight of the outer layer. The particles can have an average particle size of at least 0.5 microns or at least 1 micron and no more than 15 microns, no more than 12 microns, or no more than 10 microns. Particle size can be determined using conventional methods, for example, using a particle size instrument such as Model BI-90 from Brookhaven Instrument. Particle size can be measured in the powder state. Particle size can show the size of the agglomerated core shell particles. The core-shell particles can be purchased with a nominal particle size specified by the supplier. The core / shell particles can be formed from acrylic monomers such as butyl acrylate, 2-ethylhexyl acrylate, and lauryl methacrylate.

[0044] The core / shell polymer particles can be characterized in that the polymer in the core has a different refractive index than the polymer in the shell. For example, the refractive index of the polymer in the core can differ from the refractive index of the polymer in the shell by at least 0.02 or at least 0.03. Refractive index can be measured using a refractometer and following ASTM D542. The core shell material can be pressed into a thin film by a hot press to facilitate this measurement.

[0045] The core / shell particles can have an elastomeric core and a thermoplastic shell. For example, the particles can have a rubber particle core formed from a polymer comprising an elastomer or rubbery polymer as a main component, an optional intermediate layer formed from a monomer having two or more double bonds and coated on the core layer, and a shell layer formed from a polymer grafted on the core or the intermediate layer. The shell layer partially or completely covers the surface of the rubber particle core by graft polymerization of a monomer to the core. At least 30%, at least 40%, at least 50%, or at least 60% up to 95%, up to 90%, up to 85%, or up to 80% by weight of the particle can be the core.

[0046] Generally, the polymer constituting the rubber particle core can have a glass transition temperature (Tg) of 0°C or lower or -30°C or lower. g ). T g may be determined by DSC measurement or can be calculated for copolymers using the following Fox equation [Bulletin of the American Physical Society 1, 3, p. 123 (1956)]: g = w1x T g(1) + w2 T g(2) . For copolymers, w1and w2refer to the weight fraction of the two comonomers, and T g(1) and T g(2) refer to the glass transition temperatures of the two corresponding homopolymers in Kelvin. For polymers containing three or more monomers, additional terms (w n and T g(n) ) are added. The T g of a polymer phase can also be calculated by using appropriate values for the glass transition temperatures of the homopolymers, which can be found, for example, in “Polymer Handbook”, edited by J. Brandrup and E. H. Immergut, Interscience Publishers, John Wiley & Sons, Inc.

[0047] The polymer constituting the rubber particle core can be made from an elastomeric material comprising 50 to 100% by weight of at least one member selected from the group consisting of diene monomers (conjugated diene monomers) and (meth)acrylate monomers and 0 to 50% by weight of other copolymerizable vinyl monomers, a polysiloxane type elastomer, or a combination thereof, with the weight percentages being based on the total weight of the elastomeric material. The term “(meth)acryl” is defined as acryl and / or methacryl.

[0048] Diene monomers (conjugated diene monomers) used for preparing the elastomeric material can include, but are not limited to, for example, butadiene, isoprene, and chloroprene. Butadiene can be used in some embodiments. Further, (meth)acrylate monomers can include, for example, butyl acrylate, 2-ethylhexyl acrylate, and lauryl methacrylate, and can be used individually or in combination.

[0049] Further, the elastomeric material of the diene monomers or (meth)acrylate monomers mentioned above can also be a copolymer of a vinyl monomer copolymerizable therewith. The vinyl monomers copolymerizable with the diene monomers or (meth)acrylate monomers can include, for example, aromatic vinyl monomers and vinyl cyanide monomers. Examples of the aromatic vinyl monomers that can be used include, but are not limited to, styrene, a-methylstyrene, and vinyl naphthalene, while examples of the vinyl cyanide monomers that can be used include, but are not limited to, (meth)acrylonitrile and substituted acrylonitrile. The aromatic vinyl monomers and the vinyl cyanide monomers can be used individually or in combination.

[0050] The amount of the diene monomers or (meth)acrylate monomers used can be in the range of 50 to 100% by weight or 60 to 100% by weight, based on the total weight of the elastomeric material. If the amount of the diene monomers or (meth)acrylate monomers used for the entire rubber elastomer is less than 50% by weight, the ability of the polymer particle to toughen the polymer network, such as the cured epoxy matrix, is reduced. The amount of the monomers copolymerizable therewith can be 50% by weight or less or 40% by weight or less, based on the total weight of the elastomeric material.

[0051] Further, as a component constituting the elastomeric material, a multifunctional monomer can also be included for controlling the degree of crosslinking. The multifunctional monomer can include, for example, divinylbenzene, butanediol di(meth)acrylate, triallyl (iso)cyanurate, allyl (meth)acrylate, itaconic acid diallyl ester, and phthalic acid diallyl ester. The multifunctional monomer can be used in an amount in the range of 0 to 10% by weight, 0 to 3% by weight, or 0 to 0.3% by weight, based on the total weight of the elastomeric material. In the case where the amount of the multifunctional monomer exceeds 10% by weight, the ability of the polymer particle to toughen the polymer network can be reduced.

[0052] Optionally, a chain transfer agent can be used to control the molecular weight or crosslinking density of the polymer constituting the elastomeric material. The chain transfer agent can include, for example, an alkyl mercaptan containing 5 to 20 carbon atoms. The amount of the chain transfer agent in the formulation can be in the range of 0 to 5% by weight or 0 to 3% by weight, based on the total weight of the elastomeric material. In the case where the amount exceeds 5% by weight, the amount of the non-crosslinked portion in the rubber particle core increases, which can result in an undesirable effect on the heat resistance, stiffness, etc. of the composition when it is incorporated into the epoxy resin composition.

[0053] A silicone type elastomer can be used instead of or in combination with the above-mentioned elastomer material as the rubber particle core. In the case where a silicone type elastomer is used as the rubber particle core, a silicone type elastomer composed of a dialkyl- or diaryl-substituted siloxy unit (e.g., dimethylsiloxy, methylphenylsiloxy, and diphenylsiloxy) can be used. When such a silicone type elastomer is used, a crosslinked structure can be introduced by using a multifunctional alkoxysilane compound or by radical polymerization of a silane compound having a vinylic reactive group.

[0054] The polymer particle can be configured to have an intermediate layer between the elastomer core layer and the shell layer. The intermediate layer is formed by using a monomer having two or more polymerizable (radically polymerizable) double bonds in a single molecule (hereinafter sometimes referred to as "monomer for intermediate layer formation"). By one of the double bonds, the monomer for intermediate layer formation graft-polymerizes with the polymer forming the elastomer core layer, substantially chemically bonding the intermediate layer and the shell layer, while, by the remaining double bond, the surface of the elastomer core layer can be crosslinked or can be bonded to the shell layer. This can improve the grafting efficiency of the shell layer, as many double bonds are disposed in the elastomer core layer. The intermediate layer is present in an amount of 0% by weight or 0.2% by weight to 7% by weight of the polymer particle. The monomer having two or more double bonds can be selected from the group consisting of (meth)acrylate type multifunctional monomers, isocyanuric acid derivatives, aromatic vinyl type multifunctional monomers, and aromatic polycarboxylates. The radically polymerizable double bond more effectively forms a crosslinked layer covering the surface of the elastomer core layer. The mass of the monomer forming the intermediate layer is equal to the mass of the intermediate layer, assuming that all of the monomers added to the formulation participate in the reaction forming the intermediate layer.

[0055] The shell layer can graft-polymerize with the polymer constituting the rubber particle core, thereby forming a chemical bond with the polymer constituting the core, substantially directly or through the intermediate layer. At least 70% by weight, at least 80% by weight, or at least 90% by weight of the polymer constituting the shell layer can be bonded to the core.

[0056] The polymer constituting the shell layer can be a polymer or copolymer obtained by polymerizing or copolymerizing one or more components selected from the group consisting of (meth)acrylates, aromatic vinyl compounds, vinyl cyanoate compounds, unsaturated acid derivatives, (meth)acrylamide derivatives, and maleimide derivatives.

[0057] Examples of (meth)acrylates that can be used include, but are not limited to, alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. Examples of aromatic vinyl compounds include, but are not limited to, styrene, a-methylstyrene, alkyl-substituted styrenes, and halogen-substituted styrenes such as bromostyrene or chlorostyrene.

[0058] Examples of cyano acid ester compounds include, but are not limited to, (meth)acrylonitrile and substituted acrylonitriles. Examples of monomers containing reactive functional groups include, but are not limited to, 2-hydroxyethyl (meth)acrylate, 2-aminoethyl (meth)acrylate, glycidyl (meth)acrylate, and (meth)acrylates having reactive side chains. Examples of vinyl ethers containing reactive groups include, but are not limited to, glycidyl vinyl ether and allyl vinyl ether. Examples of unsaturated carboxylic acid derivatives include, but are not limited to, (meth)acrylic acid, itaconic acid, crotonic acid, and maleic anhydride. Examples of (meth)acrylamide derivatives include, but are not limited to, (meth)acrylamide (including N-substituted products).

[0059] Examples of maleimide derivatives include, but are not limited to, maleimide (including N-substituted products).

[0060] The shell polymer can comprise at least 5 wt%, at least 10 wt%, at least 15 wt%, or at least 20 wt% up to 70 wt%, up to 60 wt%, or up to 50 wt%, based on the total weight of the particle.

[0061] The weight ratio of the core layer to the shell layer of the preferred rubber particles can be in the range of at least 30:70, at least 40:60, or at least 50:50 up to 95:5, up to 90:10, up to 85:15, or up to 80:20.

[0062] The shell can have a Tgof at least 50°C, at least 70°C, or at least 100°C. g .

[0063] The core / shell polymer particles can be produced by various well-known methods, such as emulsion polymerization, suspension polymerization, or micro-suspension polymerization. Among them, the production method utilizing emulsion polymerization is suitable from the viewpoint that the composition of the core / shell polymer particles is easily designed and that the particles are easily produced on an industrial scale and maintain the quality of the rubbery polymer particles suitable for the process of the present application. As the emulsifier or dispersant in the aqueous medium, those which maintain emulsion or dispersion stability even when the pH of the aqueous latex is neutral are preferably used. Specifically, they include, for example, nonionic emulsifiers or dispersants such as various alkali metal salts or ammonium salts of acids, for example, alkyl or aryl sulfonic acids generally represented by dioctyl sulfosuccinic acid or dodecylbenzenesulfonic acid, alkyl or aryl sulfonic acids generally represented by dodecylsulfonic acid, alkyl or aryl ether sulfonic acids, alkyl or aryl substituted phosphoric acids, alkyl or aryl ether substituted phosphoric acids, or N-alkyl or aryl sarcosinic acids generally represented by dodecylsarcosinic acid, alkyl or aryl carboxylic acids generally represented by oleic acid or stearic acid, alkyl or aryl ether carboxylic acids, and alkyl or aryl substituted polyethylene glycols, and dispersants such as polyvinyl alcohol, alkyl substituted cellulose, polyvinylpyrrolidone, or polyacrylic acid derivatives. They can be used alone or in combination of two or more.

[0064] The particles can have an alkyl acrylate copolymer core surrounded by a methyl methacrylate copolymer shell. The particles can have a T g core of less than 0°C and a T g shell of at least 100°C. Suitable commercially available particles include PARALOID TM EXL 5136 from Dow Chemical Company.

[0065] The outer layer can include more than one (e.g., 2 or 3) type of the polymer particles as described above.

[0066] In some embodiments, the outer layer can further include a first polyethylene having a density of 0.925 g / cm3 3 to 0.970 g / cm3 3 and a melt index (I2) of 0.8 g / 10 min to 10 g / 10 min. The first polyethylene is different from the first low density polyethylene having a density of 0.919 g / cm3 3 to 0.940 g / cm3 3 and a melt index (I2) of 0.3 g / 10 min to 5 g / 10 min discussed above.

[0067] The first polyethylene useful in the outer layer has a density of 0.925 g / cm3 3 to 0.970 g / cm3 3 . The first polyethylene useful in the outer layer has a density of 0.925 g / cm3 3 to 0.970 g / cm3 3all individual values and subranges thereof are included herein and disclosed herein; for example, the first polyethylene can have a density of 0.925 g / cm3 3 , 0.930 g / cm3 3 , 0.935 g / cm3 3 , 0.940 g / cm3 3 , 0.945 g / cm3 3 , 0.950 g / cm3 3 , 0.955 g / cm3 3 , or 0.960 g / cm3 3 to an upper limit of 0.945 g / cm3 3 , 0.950 g / cm3 3 , 0.955 g / cm3 3 , 0.960 g / cm3 3 , 0.965 g / cm3 3 , or 0.970 g / cm3 3 . In some embodiments, the first polyethylene has a density of 0.960 g / cm3 3 to 0.970 g / cm3 3 .

[0068] In some embodiments, the first polyethylene has a melt index (I2) of 0.8 g / 10 min to 10 g / 10 min. All individual values and subranges from 0.8 g / 10 min to 10 g / 10 min are included herein and disclosed herein. For example, the first polyethylene can have a lower limit of 0.8 g / 10 min, 1.0 g / 10 min, 1.2 g / 10 min, 1.5 g / 10 min, 1.8 g / 10 min, 2 g / 10 min, 2.5 g / 10 min, 3 g / 10 min, 3.5 g / 10 min, 4 g / 10 min, 4.5 g / 10 min, 5 g / 10 min, 5.5 g / 10 min, 6 g / 10 min, or 6.5 g / 10 min to an upper limit of 4 g / 10 min, 4.5 g / 10 min, 5 g / 10 min, 5.5 g / 10 min, 6 g / 10 min, 6.5 g / 10 min, 7 g / 10 min, 7.5 g / 10 min, 8 g / 10 min, 8.5 g / 10 min, 9 g / 10 min, 9.5 g / 10 min, or 10 g / 10 min. For example, the first polyethylene can have an I2 of 6 g / 10 min to 10 g / 10 min.

[0069] In some embodiments, the first polyethylene can be an optional component in the outer layer. In embodiments where the outer layer includes a first polyethylene, the outer layer contains up to 50 weight percent of the first polyethylene, based on the total weight of the outer layer. All individual values and subranges from up to 50 weight percent (wt%) are included herein and disclosed herein; for example, the amount of the first polyethylene can be from a lower limit of 1 wt%, 3 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, or 40 wt% to an upper limit of 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, or 50 wt%. For example, the amount of the first polyethylene can be up to 20 wt%, or in the alternative, from 1 wt% to 20 wt%, or in the alternative, from 5 wt% to 20 wt%.

[0070] Examples of polyethylenes that can be used as the first polyethylene in the outer layer include, for example, low density polyethylene, linear low density polyethylene, medium density polyethylene, reinforced polyethylene, and high density polyethylene. In some embodiments, the first polyethylene is a high density polyethylene. Examples of commercially available polyethylenes that can be used as the first polyethylene include DOWLEX TM 2006G high density polyethylene, ELITE TM 5960G1 reinforced polyethylene, DOWLEX TM 2750ST high density polyethylene, ELITE TM 5940ST reinforced polyethylene, DOWLEX TM 2740G polyethylene, DOWLEX TM 2062GC polyethylene and ELITE TM AT 6900 reinforced polyethylene, each of which is available from The Dow Chemical Company.

[0071] In some embodiments, the outer layer of the present multilayer film further comprises a compatibilizer. The compatibilizer can advantageously provide for the smooth dispersion of the polymeric particles within the base resin (e.g., the first low density polyethylene and any additional polyethylenes). The compatibilizer is a polymer that is characterized in that it has a similar chemical structure to the base polymer and has pendant and / or end groups that have an affinity for the core / shell polymeric particles. Thus, when the base polymer is a polyolefin, the compatibilizer can be a polyolefin of the same class (e.g., if the base polymer is a polyethylene, the compatibilizer advantageously can be a polyethylene functionalized with groups that have an affinity for the shell material). In various embodiments, the compatibilizer can be a polyolefin / acrylate copolymer (e.g., a polyethylene / acrylate copolymer, such as ELVALOY AC TM) or polyolefin / acrylic copolymers (e.g., polyethylene / acrylic copolymers such as NUCREL TM ), or polyolefin / carboxylic acid copolymers, or polyolefin / maleic anhydride ester copolymers. In some embodiments, the polyolefin-based compatibilizer can be grafted with one or more anhydride groups or acrylic ester groups or acrylic acid groups. For example, if the base polymer comprises LDPE as its only or primary component, the compatibilizer can be polyethylene such as LDPE or HDPE grafted with anhydride groups such as maleic anhydride. One example is FUSABOND TM E265. The amount of compatibilizer can be 0.5 wt% or 1 wt% up to 30 wt%, up to 20 wt%, up to 15 wt%, or up to 10 wt%, based on the total weight of the outer layer. In some embodiments, the amount of compatibilizer is 0.5 wt% to 10 wt%, based on the total weight of the outer layer. The amount of compatibilizer can increase as the amount of acrylic polymer particles increases. The compatibilizer can be a mixture of polymers as described above as compatibilizers.

[0072] The outer layer of the multilayer film can comprise one or more additives as are known in the art. Such additives include antioxidants such as IRGANOX 1010 and IRGAFOS 168 (commercially available from BASF), ultraviolet absorbers, antistatic agents, pigments, dyes, nucleating agents, fillers, slip agents, flame retardants, plasticizers, processing aids, lubricants, stabilizers, smoke suppressants, viscosity control agents, surface modifiers, and anti-blocking agents.

[0073] second layer

[0074] The multilayer film according to embodiments of the application further comprises a second layer in adhering contact with the outer surface. In some embodiments, the second layer comprises (i) 1 wt% to 80 wt% of a second low density polyethylene having a density of 0.919 g / cm 3 to 0.940 g / cm 3 and a melt index (I2) of 0.3 g / 10 min to 5 g / 10 min, and (ii) 20 wt% to 99 wt% of a high density polyethylene having a density of 0.925 g / cm 3 to 0.970 g / cm 3and a second polyethylene having a melt index (I2) from 0.8 g / 10 min to 10 g / 10 min, each based on the total weight of the outer layer. In some embodiments, the second low density polyethylene used in the second layer is the same as the first low density polyethylene used in the outer layer (i.e., the same density, melt index (I2), and polymer architecture). In some embodiments, the second polyethylene used in the second layer is the same as the first polyethylene used in the outer layer (i.e., the same density, melt index (I2), and polymer architecture). In some embodiments, the second low density polyethylene used in the second layer is the same as the first low density polyethylene used in the outer layer, and the second polyethylene used in the second layer is the same as the first polyethylene used in the outer layer.

[0075] With respect to the second low density polyethylene used in the second layer, the low density polyethylene has a density from 0.919 g / cm3to 0.940 g / cm3. All individual values and subranges from 0.919 g / cm3to 0.940 g / cm3are included herein and disclosed herein; for example, the density of the second low density polyethylene can be from a lower limit of 0.919 g / cm3, 0.920 g / cm3, 0.922 g / cm3, 0.925 g / cm3, 0.927 g / cm3, 0.929 g / cm3, or 0.930 g / cm3to an upper limit of 0.925 g / cm3, 0.930 g / cm3, 0.935 g / cm3, or 0.940 g / cm3. In some embodiments, the second low density polyethylene has a density from 0.930 g / cm3to 0.940 g / cm3. 3 3 With respect to the second low density polyethylene used in the second layer, the low density polyethylene has a density from 0.919 g / cm3to 0.940 g / cm3. All individual values and subranges from 0.919 g / cm3to 0.940 g / cm3are included herein and disclosed herein; for example, the density of the second low density polyethylene can be from a lower limit of 0.919 g / cm3, 0.920 g / cm3, 0.922 g / cm3, 0.925 g / cm3, 0.927 g / cm3, 0.929 g / cm3, or 0.930 g / cm3to an upper limit of 0.925 g / cm3, 0.930 g / cm3, 0.935 g / cm3, or 0.940 g / cm3. In some embodiments, the second low density polyethylene has a density from 0.930 g / cm3to 0.940 g / cm3. 3 3 With respect to the second low density polyethylene used in the second layer, the low density polyethylene has a density from 0.919 g / cm3to 0.940 g / cm3. All individual values and subranges from 0.919 g / cm3to 0.940 g / cm3are included herein and disclosed herein; for example, the density of the second low density polyethylene can be from a lower limit of 0.919 g / cm3, 0.920 g / cm3, 0.922 g / cm3, 0.925 g / cm3, 0.927 g / cm3, 0.929 g / cm3, or 0.930 g / cm3to an upper limit of 0.925 g / cm3, 0.930 g / cm3, 0.935 g / cm3, or 0.940 g / cm3. In some embodiments, the second low density polyethylene has a density from 0.930 g / cm3to 0.940 g / cm3. 3 3 3 3 3 3 3 3 3 3 3 With respect to the second low density polyethylene used in the second layer, the low density polyethylene has a density from 0.919 g / cm3to 0.940 g / cm3. All individual values and subranges from 0.919 g / cm3to 0.940 g / cm3are included herein and disclosed herein; for example, the density of the second low density polyethylene can be from a lower limit of 0.919 g / cm3, 0.920 g / cm3, 0.922 g / cm3, 0.925 g / cm3, 0.927 g / cm3, 0.929 g / cm3, or 0.930 g / cm3to an upper limit of 0.925 g / cm3, 0.930 g / cm3, 0.935 g / cm3, or 0.940 g / cm3. In some embodiments, the second low density polyethylene has a density from 0.930 g / cm3to 0.940 g / cm3. 3 3 With respect to the second low density polyethylene used in the second layer, the low density polyethylene has a density from 0.919 g / cm3to 0.940 g / cm3. All individual values and subranges from 0.919 g / cm3to 0.940 g / cm3are included herein and disclosed herein; for example, the density of the second low density polyethylene can be from a lower limit of 0.919 g / cm3, 0.920 g / cm3, 0.922 g / cm3, 0.925 g / cm3, 0.927 g / cm3, 0.929 g / cm3, or 0.930 g / cm3to an upper limit of 0.925 g / cm3, 0.930 g / cm3, 0.935 g / cm3, or 0.940 g / cm3. In some embodiments, the second low density polyethylene has a density from 0.930 g / cm3to 0.940 g / cm3.

[0076] ​​​​​​​​​​​​​In some embodiments, the second low density polyethylene has a melt index (I2) of 0.3 g / 10 minutes to 5 g / 10 minutes. All individual values and subranges from 0.3 g / 10 minutes to 5 g / 10 minutes are included herein and disclosed herein. For example, the second low density polyethylene can have a lower limit of 0.3 g / 10 minutes, 0.5 g / 10 minutes, 0.7 g / 10 minutes, 0.9 g / 10 minutes, 1.0 g / 10 minutes, 1.2 g / 10 minutes, 1.5 g / 10 minutes, 1.8 g / 10 minutes, 2.0 g / 10 minutes, 2.3 g / 10 minutes, 2.5 g / 10 minutes, 2.7 g / 10 minutes, 3.0 g / 10 minutes, 3.3 g / 10 minutes, or 3.5 g / 10 minutes to an upper limit of 2.0 g / 10 minutes, 2.5 g / 10 minutes, 2.8 g / 10 minutes, 3.0 g / 10 minutes, 3.2 g / 10 minutes, 3.5 g / 10 minutes, 3.7 g / 10 minutes, 4.0 g / 10 minutes, 4.2 g / 10 minutes, 4.5 g / 10 minutes, 4.8 g / 10 minutes, or 5 g / 10 minutes. For example, the second low density polyethylene can have an I2of 2.5 g / 10 minutes to 4.0 g / 10 minutes.

[0077] The second layer comprises 1 wt% to 100 wt% of the second low density polyethylene, based on the total weight of the second layer. All individual values and subranges from 1 wt% to 80 wt% (wt%) are included herein and disclosed herein; for example, the amount of second low density polyethylene can have a lower limit of 1 wt%, 3 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, or 60 wt% to an upper limit of 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 75 wt%, or 80 wt%. For example, the amount of second low density polyethylene can be 50 wt% to 100 wt%, or in the alternative, 60 wt% to 100 wt%, or in the alternative, 70 wt% to 100 wt%.

[0078] In some embodiments, examples of low density polyethylene that can be used in the second layer include DOW TM Low density polyethylene (LDPE), which is commercially available from The Dow Chemical Company, such as DOW TM LDPE 525E, DOW TM LDPE 410E, DOW TM LDPE 421E, DOW TM LDPE 545E, DOW TM LDPE 555E, and DOWTM LDPE 515E.

[0079] In addition to the LDPE, the second layer also includes a second polyethylene having a density of 0.925 g / cm 3 to 0.970 g / cm 3 and a melt index (I2) of 0.8 g / 10 minutes to 10 g / 10 minutes. The second polyethylene is different from the second low density polyethylene having a density of 0.919 g / cm 3 to 0.940 g / cm 3 and a melt index (I2) of 0.3 g / 10 minutes to 5 g / 10 minutes discussed above. As noted above, the second polyethylene in the second layer can be the same as the first polyethylene used in the outer layer. In some embodiments, both the first polyethylene used in the outer layer and the second polyethylene used in the second layer can be a high density polyethylene.

[0080] The second polyethylene useful in the outer layer has a density of 0.925 g / cm 3 to 0.970 g / cm 3 . All individual values and subranges from 0.925 g / cm 3 to 0.970 g / cm 3 are included herein and disclosed herein; for example, the second polyethylene can have a density of a lower limit of 0.925 g / cm 3 , 0.930 g / cm 3 , 0.935 g / cm 3 , 0.940 g / cm 3 , 0.945 g / cm 3 , 0.950 g / cm 3 , 0.955 g / cm 3 , or 0.960 g / cm 3 to an upper limit of 0.945 g / cm 3 , 0.950 g / cm 3 , 0.955 g / cm 3 , 0.960 g / cm 3 , 0.965 g / cm 3 , or 0.970 g / cm 3 . In some embodiments, the second polyethylene has a density of 0.960 g / cm 3 to 0.970 g / cm 3 .

[0081] In some embodiments, the second polyethylene has a melt index (I2) of 0.8 g / 10 min to 10 g / 10 min. All individual values and subranges of 0.8 g / 10 min to 10 g / 10 min are included herein and disclosed herein. For example, the I2of the second polyethylene can have a lower limit of 0.8 g / 10 min, 1.0 g / 10 min, 1.2 g / 10 min, 1.5 g / 10 min, 1.8 g / 10 min, 2 g / 10 min, 2.5 g / 10 min, 3 g / 10 min, 3.5 g / 10 min, 4 g / 10 min, 4.5 g / 10 min, 5 g / 10 min, 5.5 g / 10 min, 6 g / 10 min, or 6.5 g / 10 min and an upper limit of 4 g / 10 min, 4.5 g / 10 min, 5 g / 10 min, 5.5 g / 10 min, 6 g / 10 min, 6.5 g / 10 min, 7 g / 10 min, 7.5 g / 10 min, 8 g / 10 min, 8.5 g / 10 min, 9 g / 10 min, 9.5 g / 10 min, or 10 g / 10 min. For example, the second polyethylene can have an I2of 6 g / 10 min to 10 g / 10 min.

[0082] The second layer comprises 20 wt% to 99 wt% of the second polyethylene, based on the total weight of the second layer. All individual values and subranges of 20 wt% to 99 wt% (wt%) are included herein and disclosed herein; for example, the amount of second polyethylene can have a lower limit of 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 76 wt%, or 80 wt% and an upper limit of 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 75 wt%, 80 wt%, 85 wt%, 90 wt%, 95 wt%, or 99 wt%. For example, the amount of second polyethylene can be 1 wt% to 50 wt%, or in the alternative, 1 wt% to 40 wt%, or in the alternative, 1 wt% to 30 wt%.

[0083] Examples of polyethylenes that can be used as the second polyethylene in the second layer include, for example, low density polyethylene, linear low density polyethylene, medium density polyethylene, reinforced polyethylene, and high density polyethylene. In some embodiments, the second polyethylene is a high density polyethylene. Examples of commercially available polyethylenes that can be used as the second polyethylene include DOWLEX TM 2006G high density polyethylene, ELITE TM 5960G1 reinforced polyethylene, DOWLEX TM 2750ST high density polyethylene, ELITE TM5940 ST enhanced polyethylene, DOWLEX TM 2740 G polyethylene, DOWLEX TM 2062 GC polyethylene and ELITE TM AT 6900 enhanced polyethylene, each of which is available from The Dow Chemical Company.

[0084] The second layer of the multilayer film can include one or more additives as known in the art. Such additives include antioxidants such as IRGANOX 1010 and IRGAFOS 168 (commercially available from BASF), ultraviolet absorbers, antistatic agents, pigments, dyes, nucleating agents, fillers, slip agents, flame retardants, plasticizers, processing aids, lubricants, stabilizers, smoke suppressants, viscosity control agents, surface modifiers, and anti-blocking agents.

[0085] other layers

[0086] In addition to the outer layer and the second layer, the multilayer film of the present application can include a variety of other layers. Such layers will be in adhering contact with the second layer or another intervening layer. The number of layers in the multilayer film can depend on a variety of factors including, for example, the desired properties of the film, the end use application, the desired thickness of the film, and the like. For example, when the multilayer film is used in packaging, the other layers can be different than those used when the multilayer film is used as a label. Examples of different layers that can be used in various embodiments are discussed further herein. In some embodiments, the multilayer film of the present application includes up to 13 layers. In various embodiments, the multilayer film includes 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or 13 layers.

[0087] In some embodiments, the multilayer film of the present application includes a second outer layer that is a sealant layer. The sealant layer can be used to form an article or a package by adhering the film to another film, laminate, or itself using the sealant layer. In some embodiments, the sealant layer can include any resin known to one of ordinary skill in the art to be useful as a sealant layer. In some embodiments of the present application, examples of polymers that can be used to form a sealant layer include, but are not limited to, LDPE (e.g., DOW TM LDPE and AGILITY TM LDPE), LLDPE (e.g., DOWLEX TM LLDPE resins), polyolefin plastomers or elastomers (e.g., AFFINITY TM plastomers and elastomers), ethylene-vinyl acetate copolymers (e.g., ELVAX TMionomers of ethylene-vinyl acetate copolymers) and ethylene acid copolymers (e.g., SURLYN TM ionomers of ethylene-vinyl acetate copolymers) and ethylene acid copolymers (e.g., SURLYN

[0088] In some embodiments, the multilayer film includes a second outer layer providing a second matte surface. In some embodiments, the second outer layer has a gloss measured by ASTM D2457 at a 45° angle of less than 50%. In some such embodiments, the second outer layer has the same composition as the first outer layer. In some such embodiments, the second outer layer comprises (i) 30 wt% to 99.5 wt% of a low density polyethylene having a density of 0.919 g / cm3 3 to 0.940 g / cm3 3 and a melt index (I2) of 0.3 g / 10 min to 5 g / 10 min, (ii) 0.1 wt% to 20 wt% of polymer particles having a core and a shell structure, wherein the core comprises a first polymeric material having a first refractive index and the shell comprises a second polymeric material having a second refractive index different from the first refractive index, and (iii) optionally, up to 50 wt% of a polyethylene having a density of 0.925 g / cm3 3 to 0.970 g / cm3 3 and a melt index (I2) of 0.8 g / 10 min to 10 g / 10 min, each based on the total weight of the second outer layer.

[0089] In some embodiments, the multilayer film is a five layer structure, where the first outer layer has a gloss measured by ASTM D2457 at a 45° angle of less than 50% to provide a matte surface. The core or innermost layer has the composition of the second layer as described above. In some embodiments, the second outer layer can provide a second matte surface (a gloss measured by ASTM D2457 at a 45° angle of less than 50%) or can be a sealant layer as described above. There are two intermediate layers or sub-surface layers, where one intermediate layer is between the first outer layer and the core layer and the second intermediate layer is between the second outer layer and the core layer. In some embodiments, the intermediate layers can be formed from high density polyethylene or a blend of high density polyethylene and linear low density polyethylene where the HDPE is present in greater amounts.

[0090] In some embodiments, depending on the desired use or requirements of the multilayer film, the film can include other layers, such as a barrier layer. For example, for some uses, it can be desirable for the film to provide a barrier to moisture, light, flavor / odor, and / or oxygen transmission. Such barrier layers can comprise, for example, polyamide, ethylene-vinyl alcohol copolymer, and other polymers known to those skilled in the art for use in barrier layers. In such embodiments, the inner layer of the multilayer film comprises ethylene-vinyl alcohol copolymer or polyamide. In some such embodiments, the multilayer film comprises 30 wt% or less ethylene-vinyl alcohol copolymer and polyamide, based on the total weight of the multilayer film. In some embodiments, the multilayer film comprises 20 wt% or less ethylene-vinyl alcohol copolymer and polyamide, based on the total weight of the multilayer film. In some embodiments, the multilayer film comprises 10 wt% or less ethylene-vinyl alcohol copolymer and polyamide, based on the total weight of the multilayer film. In some embodiments, the multilayer film comprises less than 5 wt% ethylene-vinyl alcohol copolymer and polyamide, based on the total weight of the multilayer film.

[0091] In embodiments including an inner layer having ethylene-vinyl alcohol copolymer or polyamide, one or more tie layers can be included in the film to adhere the barrier layer to the polyethylene-based layers, as would be known to one skilled in the art based on the teachings herein. In general, a wide variety of tie layer compositions can be used to form the tie layer, as would be known to one skilled in the art based on the teachings herein.

[0092] In some embodiments, barrier properties can be less important for the multilayer film. In some such embodiments, the multilayer film can comprise less than 0.5 wt% ethylene-vinyl alcohol copolymer and polyamide, based on the total weight of the film. In some embodiments, the multilayer film comprises less than 0.1 wt% ethylene-vinyl alcohol copolymer and polyamide, based on the total weight of the film. In some embodiments, the multilayer film is free of ethylene-vinyl alcohol copolymer and polyamide.

[0093] In some embodiments, the multilayer film of the present application has a total thickness of at most 30 micrometers. In some embodiments, the multilayer film has a thickness of at most 90 micrometers. In some embodiments, the multilayer film has a thickness of from 30 micrometers to 90 micrometers.

[0094] The multilayer films of the present application can exhibit one or more desirable properties. As discussed elsewhere, the multilayer films of the present application have a matte surface. The outer layer of the multilayer film provides the matte surface because the outer layer has one or both of (1) a gloss less than 50% and (2) a haze greater than 45%. In some embodiments, the outer layer has a gloss less than 50% measured by ASTM D2457 at a 45° angle. In some embodiments, the outer layer has a gloss less than 45% measured by ASTM D2457 at a 45° angle. In some embodiments, the outer layer has a haze greater than 45% measured by ASTM D1003. In some embodiments, the outer layer has a haze greater than 50% measured by ASTM D1003. In some embodiments, the outer layer has a haze greater than 55% measured by ASTM D1003. In some embodiments, the outer layer has a gloss less than 50% measured by ASTM D2457 at a 45° angle and a haze greater than 45% measured by ASTM D1003. In some embodiments, the outer layer has a gloss less than 45% measured by ASTM D2457 at a 45° angle and a haze greater than 50% measured by ASTM D1003. In some embodiments, the outer layer has a gloss less than 45% measured by ASTM D2457 at a 45° angle and a haze greater than 55% measured by ASTM D1003.

[0095] The multilayer films can be co-extruded into blown films or cast films using techniques known to those of skill in the art based on the teachings herein. In particular, blown film manufacturing lines and cast film manufacturing lines can be configured for co-extruding the multilayer films of the present application in a single extrusion step using techniques known to those of skill in the art based on the compositions of the different film layers disclosed herein.

[0096] label

[0097] Embodiments of the present application also include labels formed from or incorporating the multilayer films of the present application. Such labels can be made from the multilayer films of the present application using techniques known to those of ordinary skill in the art based on the teachings herein.

[0098] packaging

[0099] Embodiments of the present application also include packages formed from or incorporating the multilayer films of the present application. Such packages can be made from the multilayer films of the present application using techniques known to those of ordinary skill in the art based on the teachings herein.

[0100] Examples of such packages can include flexible packages, pouches, stand-up pouches, and pre-made packages or pouches. In some embodiments, the multilayer films of the present application can be used for food packaging. Examples of food that can be included in such packages include meat, cheese, grains, nuts, juice, sauces, and the like. Such packages can be formed using techniques known to those skilled in the art based on the teachings herein and based on the particular use of the package (e.g., the type of food, the amount of food, etc.).

[0101] test method

[0102] The following analytical methods were used to describe various aspects of the present application, unless otherwise indicated herein:

[0103] melt index

[0104] Melt Index, I2(or I2) and I10(or I10) 10 (I10) were measured according to ASTM D-1238 (Method B) at 190 °C and under 2.16 kg and 10 kg loads, respectively. Their values are reported in g / 10 min.

[0105] density

[0106] Samples for density measurements were prepared according to ASTM D4703. Measurements were made according to ASTM D792, Method B within one hour of pressing the sample.

[0107] haze

[0108] Haze was measured according to ASTM D 1003. Hazegard Plus (BYK-Gardner USA; Columbia, MD) was used for testing. For each test, 5 samples were examined and the average value was reported. The area of six centimeters in diameter was measured on each film sample.

[0109] gloss

[0110] Gloss at 45° angle was measured according to ASTM D2457 on a BYK-Gardner (Columbia, MD) Micro-Gloss 45° Glossmeter (Columbia, MD).

[0111] md and cd elmendorf tear strength

[0112] Elmendorf tear strength in the longitudinal and transverse directions is measured according to ASTM D1922. The force required to propagate a tear across a membrane or sheet sample, in grams, is measured using a precisely calibrated pendulum apparatus. The pendulum, acting under gravity, swings in an arc, thus tearing the sample from a pre-cut slit. One side of the sample is fixed by the pendulum, and the other by a fixing member. The energy loss of the pendulum is indicated by a pointer or electronic scale. The scale indication is a function of the force required to tear the sample. The samples used are of “constant radius geometry” as specified in D1922. Samples cut from the MD and CD directions are typically tested. The sample thickness is measured at the center of the sample prior to testing. A total of 10 samples are tested in each direction, and the average tear strength is reported. Samples torn at an angle greater than 60° to the vertical are described as having an “oblique” tear—this type of tear should be noted, although the strength value is included in the average strength calculation. Some embodiments of the invention will now be described in detail in the following examples.

[0113] examples

[0114] As further discussed below, various membranes of the present invention and comparative membranes are prepared using the following materials:

[0115] ·DOW TM LDPE 525E (hereinafter referred to as "LDPE"): density is 0.9315 g / cm³. 3 Low-density polyethylene with a melt flow index (I2) of 3.2 g / 10 min.

[0116] DOWLEX TM 2006 (hereinafter referred to as "HDPE"): density is 0.963 g / cm³ 3 It is a high-density polyethylene with a melt flow index (I2) of 8 g / 10 min.

[0117] Paralleloid TM EXL-5136 (hereinafter referred to as "polymer particles"): Polymer particles with a core and shell structure. The polymer material used in the core is an elastomer and has a glass transition temperature <0°C (T0). g The polymer material used in the shell is thermoplastic and has a glass transition temperature >100°C (T0). g The polymer material in the core has a different refractive index than the polymer material in the shell. The average particle size of the polymer particles is between 1 micrometer and 10 micrometers.

[0118] ·FUSABOND TM E265 (hereinafter referred to as "compensator"): density is 0.950 g / cm³. 3and high density polyethylene grafted with maleic anhydride having a melt index (I2) of 12 g / 10 min.

[0119] Each of these materials is commercially available from The Dow Chemical Company.

[0120] The following films having a structure of Layer A / Layer B / Layer C were prepared:

[0121] table 1

[0122]

[0123]

[0124] The components were melt blended prior to being provided to the blown film line.

[0125] In the inventive films above comprising polymer particles, the polymer particles were melt blended with the LDPE and compatibilizer (if present) prior to being provided to the blown film line. The blend was melt blended on a Buss kneader compounder at 120 rpm (kneader speed), 3 amps (motor current), 5 kg / h, 60 rpm (screw speed), and a temperature profile of 110°C / 130°C / 140°C / 120°C / 125°C.

[0126] The comparative films and inventive films above were coextruded on a Dr. Collin 3 layer coextrusion blown film line. The nominal film thickness was 80 microns. The line consisted of three 25: 1 L / D single screw extruders equipped with fluted feed zones. The screw diameters of the two outer layer extruders were 25 mm and the screw diameter of the inner layer (formed by Layer B) extruder was 30 mm. The melt temperature was 180°C - 210°C. The die diameter was 30 mm and the die gap was 1.8 mm. The blow up ratio was 2.5: 1. The output rate was 15 kg / h.

[0127] The gloss and haze at 45° of the comparative films and inventive films were measured as described in the Test Methods section. The results are shown in Table 2:

[0128] table 2

[0129]

[0130]

[0131] The effect of adding polymer particles to the film can be observed in Table 2. The addition of up to 2.5 wt% of polymer particles in one or more outer layers (Inventive film 2) resulted in a 59% reduction in gloss and a 358% increase in haze. Increasing the concentration of polymer particles in one or more outer layers to up to 3.75 wt% in combination with increasing the concentration of compatibilizer to up to 6.25 wt% (Inventive films 3-5) resulted in further improvements, with a 62% reduction in gloss and up to a 425% increase in haze. The reduction in gloss is of particular interest for matte film applications, such as labels, as a surface with lower shininess is considered more natural.

[0132] The Elmendorf tear strength of the films in the machine direction (MD) and cross direction (CD) was also measured as described in the test methods section above. The results are shown in Table 3:

[0133] table 3

[0134] elmendorf tear, md (g elmendorf tear, cd (g) comparative film a [ref 1] 215 149 comparative film b [ref 2] 122 194 inventive film 1 [dlp 1] 135 192 inventive film 2 [dlp 2] 108 182 inventive film 3 [dlpf 1] 106 180 inventive film 4 [dlpf 2] 128 227 inventive film 5 [dlp 3] 136 155 comparative film c [lpf1] 173 212

[0135] As shown in Table 3, the inclusion of polymer particles did not have a significant impact on the Elmendorf tear strength in the cross direction. While there was a negative impact on the Elmendorf tear strength in the machine direction, this was only in relation to the single material film (Comparative film A).

Claims

1. A multilayer film having at least one matte surface, comprising: (a) an outer layer comprising (i) 50% to 99.5% by weight of a material with a density of 0.930 g / cm³. 3 Up to 0.940 g / cm 3 The following are also present: (ii) a first low-density polyethylene with a melt flow index I2 of 0.3 g / 10 min to 5 g / 10 min; (ii) 0.1 wt% to 20 wt% of polymer particles having a core and shell structure, wherein the core comprises a first polymer material having a first refractive index and the shell comprises a second polymer material having a second refractive index different from the first refractive index; and (iii) optionally, up to 50 wt% of a material with a density of 0.925 g / cm³. 3 Up to 0.970 g / cm 3 The first polyethylene with a melt flow index I2 of 0.8 g / 10 min to 10 g / 10 min, each based on the total weight of the outer layer; and (b) a second layer in adhering contact with the outer layer, the second layer comprising (i) 1 wt % to 80 wt % of a second low density polyethylene having a density of 0.919 g / cm 3 to 0.940 g / cm 3 and a melt index, I2, of 0.3 g / 10 min to 5 g / 10 min, and (ii) 20 wt % to 99 wt % of a second polyethylene having a density of 0.925 g / cm 3 to 0.970 g / cm 3 and a melt index, I2, of 0.8 g / 10 min to 10 g / 10 min, each based on the total weight of the second layer, wherein the second polyethylene having a density of 0.925 g / cm 3 to 0.970 g / cm 3 and a melt index of 0.8 g / 10 min to 10 g / 10 min is different than the second low density polyethylene having a density of 0.919 g / cm 3 to 0.940 g / cm 3 and a melt index of 0.3 g / 10 min to 5 g / 10 min; wherein the outer layer has a glossiness of less than 50% measured by ASTM D2457 at a 45° angle; wherein the first polymeric material of the core of the polymeric particles is elastomeric and the second polymeric material of the shell of the polymeric particles is thermoplastic; wherein the sample for density measurement is prepared according to ASTM D2457 and is measured according to ASTM D792, Method B within 1 hour of pressing the sample, wherein the refractive index is measured using a refractometer and following ASTM D542, and wherein the first polyethylene and the second polyethylene are each high density polyethylene.

2. The multilayer film of claim 1, wherein the shell comprises an acrylic polymer.

3. The multilayer film of claim 1 or claim 2, wherein the polymeric particles have an average size of 1 micrometer to 10 micrometers, wherein particle size is determined using a particle size analyzer from Brookhaven Instruments Corporation, model BI-90.

4. The multilayer film of claim 1, wherein the outer layer further comprises a compatibilizer.

5. The multilayer film of claim 4, wherein the compatibilizer is a polyolefin copolymer with acrylic acid, a polyolefin copolymer with acrylate, or a polyolefin copolymer with maleic anhydride ester.

6. The multilayer film of claim 4, wherein the compatibilizer is a maleic anhydride grafted low density polyethylene or a maleic anhydride grafted high density polyethylene.

7. The multilayer film of any one of claims 4 to 6, wherein the compatibilizer is present in the outer layer in an amount of up to 10% by weight based on the total weight of the outer layer.

8. The multilayer film of claim 4, wherein the compatibilizer is a polyolefin copolymer grafted with one or more anhydride groups, acrylate groups, or carboxylic acid groups.

9. A label comprising the multilayer film of any one of claims 1 to 8.

10. A package comprising the multilayer film of any one of claims 1 to 8.

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