Bio-based EVA compositions, articles and methods thereof

Abstract

The polymer can include a copolymer of ethylene and vinyl acetate, wherein at least a portion of the ethylene is derived from a renewable carbon source, and wherein the copolymer has a melt index (190°C / 2.16 kg) according to ASTM D1238 in the range of 0.12 to 8.0 g / 10 min.

Description

Technical Field

[0001] Using polyolefin copolymers such as ethylene vinyl acetate (EVA), various articles including films, molded products, foams, etc. can be manufactured. Generally, polyolefins are plastics that are widely used worldwide because they are versatile in a wide range of applications. EVA can have characteristics such as high processability, low manufacturing cost, flexibility, low density, and recyclability, for example.

Prior Art Documents

Patent Documents

[0002]

Patent Document 1

Patent Document 2

Patent Document 3

Non-Patent Documents

[0003]

Non-Patent Document 1

Non-Patent Document 2

Non-Patent Document 3

[0004] This summary is provided to introduce a selection of concepts that will be further described in the embodiments for carrying out the invention described below. This summary is not intended to identify important or essential features of the subject matter described in the claims, nor is it intended to be used as an aid in limiting the scope of the subject matter described in the claims.

[0005] In one embodiment, the embodiments disclosed herein relate to an ethylene-vinyl acetate copolymer, wherein at least a portion of the ethylene is obtained from a renewable carbon source, and the copolymer has an ASTM D1238 melt index (190°C / 2.16 kg) in the range of 0.12 to 8.0 g / 10 min.

[0006] In another embodiment, the embodiments disclosed herein relate to a film comprising an ethylene-vinyl acetate copolymer, wherein at least a portion of the ethylene is obtained from a renewable carbon source, and the copolymer has an ASTM D1238 melt index (190°C / 2.16 kg) in the range of 0.12 to 8.0 g / 10 min.

[0007] In another embodiment, embodiments disclosed herein relate to a multilayer film comprising at least one film comprising an ethylene-vinyl acetate copolymer, wherein at least a portion of the ethylene is obtained from a renewable carbon source, and the copolymer has an ASTM D1238 melt index (190°C / 2.16 kg) in the range of 0.12 to 8.0 g / 10 min.

[0008] In yet another embodiment, embodiments disclosed herein relate to a method for forming an EVA film, comprising extruding bio-based EVA to form a film containing an ethylene-vinyl acetate copolymer, wherein at least a portion of the ethylene is obtained from a renewable carbon source, and the copolymer has an ASTM D1238 melt index (190°C / 2.16 kg) in the range of 0.12 to 8.0 g / 10 min.

[0009] Other aspects and advantages of the subject matter described in the claims will become apparent from the following description and the attached claims. [Modes for carrying out the invention]

[0010] In one embodiment, the embodiments disclosed herein relate to a composition comprising an ethylene vinyl acetate (EVA) copolymer, wherein at least a portion of the ethylene in the ethylene vinyl acetate copolymer is obtained from a renewable carbon source, such as plant-derived material, i.e., a bio-based ethylene vinyl acetate copolymer is formed. In particular, the embodiments disclosed herein relate to the use of such bio-based ethylene vinyl acetate copolymer in films, especially multilayer films.

[0011] EVA is a copolymer of polyolefin elastomers formed by a random arrangement of units obtained by polymerizing ethylene and vinyl acetate under high temperature and pressure. EVA copolymers provide a material that can be processed like other thermoplastics, but can exhibit rubber-like properties with flexibility and elasticity. In contrast to products derived from fossil resources, the use of products derived from natural resources is becoming increasingly preferred as an effective means of effectively limiting the expansion of the greenhouse effect by suppressing the rise in atmospheric carbon dioxide concentrations. Thus, products derived from natural raw materials differ from fossil-derived products in their renewable carbon content. This renewable carbon content can be determined by the methods described in the technical ASTM D6866-18 standard, "Standard Test Methods for Determining the Biobased Content of Solid, Liquid, and Gaseous Samples Using Radiocarbon Analysis." Furthermore, products derived from renewable natural raw materials have the advantage of being incinerable at the end of their lifecycle, releasing only non-fossil CO2.

[0012] The polymer compositions relating to this disclosure include EVA copolymers in which the mass percentage of ethylene in the EVA copolymer ranges from a lower limit selected from 60% by mass, 70% by mass, 75% by mass, 80% by mass, 82% by mass, and 85% by mass, to an upper limit selected from 80% by mass, 85% by mass, 88% by mass, 90% by mass, 93% by mass, and 95% by mass. Here, any lower limit can be paired with any upper limit. Furthermore, it is understood that at least a portion of the total amount of ethylene is derived from a renewable carbon source.

[0013] The polymer compositions relating to this disclosure are EVA copolymers incorporating various ratios of ethylene and vinyl acetate, and may also include EVA copolymers further comprising one or more optional additional comonomers. The polymer compositions relating to this disclosure may include EVA copolymers in which the mass percentage of vinyl acetate content in the copolymer, as determined by ASTM D5594, ranges from a lower limit selected from 5% by mass, 7% by mass, 10% by mass, 12% by mass, 15% by mass, and 20% by mass, to an upper limit selected from 15% by mass, 18% by mass, 20% by mass, 25% by mass, 30% by mass, or 40% by mass. Here, any lower limit may be paired with any upper limit. Furthermore, it is understood that at least a portion of the total amount of vinyl acetate may optionally be derived from a renewable carbon source.

[0014] Specifically, in one or more embodiments, the EVA copolymer has a bio-based carbon content of at least 50%, as determined by Method B of ASTM D6866-18. Furthermore, other embodiments may contain at least 40%, 50%, 60%, 80%, or 100% bio-based carbon. As described above, all of the bio-based carbon or renewable carbon in the EVA polymer may be contributions from bio-based ethylene and / or bio-based vinyl acetate. Each of these points will be explained in turn.

[0015] For example, in one or more embodiments, the renewable carbon source is one or more plant materials selected from the group consisting of sugarcane and sugar beets, maple, date palm, palm sugar, sorghum, American agave, corn, wheat, barley, sorghum, rice, potato, cassava, sweet potato, algae, fruits, cellulose-containing materials, wine, hemicellulose-containing materials, lignin-containing materials, wood, straw, sugarcane bagasse, sugarcane leaves, corn stalks, leaves and cobs, wood residue, paper, and combinations thereof.

[0016] In one or more embodiments, bio-based ethylene can be obtained by fermenting a renewable carbon source to produce ethanol, which is then dehydrated to produce ethylene. Furthermore, it is understood that fermentation also produces by-products of higher alcohols in addition to ethanol. If these higher alcohol by-products are present during dehydration, higher alkene impurities may be formed along with the ethanol. Therefore, in one or more embodiments, the ethanol may be purified before dehydration to remove the higher alcohol by-products, and in other embodiments, the ethylene may be purified after dehydration to remove higher alkene impurities.

[0017] Thus, bioethanol, a type of ethanol derived from living organisms, can be obtained by fermenting sugars obtained from cultures such as sugarcane or sugar beet, or similarly, sugars obtained from starch hydrolyzed in association with other cultures such as corn. Bio-based ethylene can also be obtained from products resulting from the hydrolysis of cellulose and hemicellulose, which can be found in many agricultural by-products such as straw and sugarcane husks. This fermentation takes place in the presence of various microorganisms, the most important of which is the yeast Saccharomyces cerevisiae. The ethanol thus obtained can usually be converted to ethylene by catalytic reactions at temperatures exceeding 300°C. For this purpose, a wide variety of catalysts can be used, such as γ-alumina with a high specific surface area. Other examples include the teachings described in U.S. Patents 9,181,143 and 4,396,789, which are incorporated herein by reference in their entirety.

[0018] On the one hand, in one or more embodiments of the EVA copolymer of the present disclosure, bio-based vinyl acetate can also be used. Bio-based vinyl acetate can be produced by oxidizing ethanol (which can be produced as described above) to produce acetic acid, and then acyl-oxidizing ethylene by reacting ethylene with acetic acid to obtain the desired vinyl acetate. Further, it is understood that the ethylene reacted with acetic acid can also be formed from a renewable source as described above.

[0019] In one or more embodiments, a renewable starting material including those described above can be fermented to produce at least one alcohol (either ethanol or a mixture of alcohols containing ethanol), and optionally purified. The alcohol may be divided into two parts, where the first part may be introduced into a first reactor and the second part may be introduced into a second reactor. In the first reactor, the alcohol can be dehydrated to produce an alkene (ethylene or a mixture of alkenes containing ethylene, depending on whether purification is performed after fermentation), and then optionally purified to obtain ethylene. Those skilled in the art can understand that if purification is performed before dehydration, it is not necessary to perform it after dehydration, and vice versa. In the second reactor, the alcohol can be oxidized to obtain acetic acid, and optionally purified. In the third reactor, the ethylene produced in the first reactor and the acetic acid produced in the second reactor can be combined and reacted to acyl-oxidize the ethylene to produce vinyl acetate, which can then be isolated and optionally purified. For further details regarding the production of acetic acid by the oxidation of ethanol, see U.S. Patent No. 5,840,971 and "Selective catalytic oxidation of ethanol to acetic acid on dispersed Mo-V-Nb mixed oxides", Li X, Iglesia E., Chemistry, 2007;13(33):9324-9330.

[0020] However, this disclosure is not limited to the acetic acid production pathways described herein. Rather, it is assumed that acetic acid may be obtained from fatty acids, as described in "The Production of Vinyl Acetate Monomer as a Co-Product from the Non-Catalytic Cracking of Soybean Oil," Benjamin Jones, Michael Linnen, Brian Tande, and Wayne Seames, Processes, 2015, 3, 61-9-633. Furthermore, as described in "Acetic acid bacteria: A group of bacteria with versatile biotechnological applications," Saichana N, Matsushita K, Adachi O, Frebort I, Frebortova J., Biotechnol Adv., November 1, 2015;33(6 Pt 2):1260-71 and "Biotechnological applications of acetic acid bacteria," Raspor P, Goranovic D, Crit Rev Biotechnol., 2008;28(2):101-24, the production of acetic acid by fermentation is carried out by acetic acid-producing bacteria. Moreover, it is understood that the production of ethylene used to produce vinyl acetate can then be used to produce ethylene for reacting with vinyl acetate to produce the EVA copolymer of this disclosure. Therefore, for example, the amount of ethanol supplied to the first and second reactors can be varied depending on the relative amounts of ethylene and vinyl acetate to be polymerized.

[0021] The polymer composition according to the present disclosure can include an EVA copolymer, wherein the melt index determined by ASTM D1238 at 190 °C using a load of 2.16 kg can range from a lower limit selected from any of 0.1 g / 10 min, 0.12 g / 10 min, 0.25 g / 10 min, 1 g / 10 min, 2 g / 10 min or 5 g / 10 min to an upper limit selected from any of 4 g / 10 min, 5 g / 10 min, 6 g / 10 min, 8 g / 10 min or 10 g / 10 min. Here, any lower limit can be paired with any upper limit.

[0022] The polymer composition according to the present disclosure can include an EVA copolymer, wherein the Shore A hardness determined by ASTM D2240 can range from a lower limit which is any of Shore A75, Shore A77, Shore A80, Shore A85, Shore A88 or Shore A90 to an upper limit which is any of Shore A90, Shore A93, Shore A95 or Shore A100. Here, any lower limit can be paired with any upper limit.

[0023] The polymer composition according to the present disclosure can include an EVA copolymer, wherein the Shore D hardness determined by ASTM D2240 can range from a lower limit which is any of Shore D20, Shore D22, Shore D25, Shore D30, Shore D40, Shore D45 or Shore D50 to an upper limit which is any of Shore D45, Shore D50, Shore D55 or Shore D60. Here, any lower limit can be paired with any upper limit.

[0024] The polymer composition according to the present disclosure can include an EVA copolymer, wherein the Vicat softening temperature determined by Method A50 of ASTM D1525 can range from a lower limit which is any of 45 °C, 50 °C, 55 °C, 58 °C or 60 °C to an upper limit which is any of 65 °C, 70 °C, 75 °C, 85 °C or 90 °C. Here, any lower limit can be paired with any upper limit.

[0025] The polymer composition according to this disclosure may include an EVA copolymer having a tensile strength at break in the range of 12 to 40 MPa, as determined by ASTM D638 using a 2 mm thick test specimen prepared from a compression molded sheet according to ASTM D4703. The tensile strength at break may range from a lower limit of 15 MPa, 17 MPa, 19 MPa, or 22 MPa to an upper limit of 25 MPa, 30 MPa, 33 MPa, 35 MPa, 35 MPa, or 40 MPa. Here, any lower limit may be used in combination with any upper limit.

[0026] The polymer composition relating to this disclosure may include an EVA copolymer having an elongation at break greater than 450%, as determined by ASTM D638 using a 2 mm thick test specimen prepared from a compression-molded sheet according to ASTM D4703. The lower limit of the elongation at break may be either 450% or 500%.

[0027] The polymer composition according to this disclosure may include an EVA copolymer having a melting point in the range of 75 to 105°C, as determined by ASTM D3418 using a 2 mm thick test specimen prepared from a compression molded sheet according to ASTM D4703. The melting point may range from a lower limit of 75°C, 86°C, 88°C, 90°C, or 92°C to an upper limit of 96°C, 98°C, 100°C, 102°C, or 105°C. Here, any lower limit may be used in combination with any upper limit.

[0028] The EVA copolymers relating to this disclosure may have the following film properties, as evaluated using a 50 μm thick film processed at a blow-up ratio of 2.3:1 in a 50 mm blow film line with a barrier screw L / D ratio of 25:1 and a die spacing of 1.0 mm.

[0029] The EVA copolymer relating to this disclosure may have a tensile strength at break of 25 to 45 MPa in the machine direction (MD), as measured in a 50 μm thick film according to ASTM D882. The lower limit of the tensile strength at break (MD) may be 25 MPa, 28 MPa, 30 MPa, or 32 MPa. The upper limit of the tensile strength at break (MD) may be 38 MPa, 40 MPa, 42 MPa, or 45 MPa. Here, any lower limit may be used in combination with any upper limit.

[0030] The EVA copolymer relating to this disclosure may have a tensile strength at break of 18 to 38 MPa in the transversal direction (TD), as measured in a 50 μm thick film according to ASTM D882. The lower limit of the tensile strength at break (TD) may be 18 MPa, 20 MPa, 22 MPa, or 24 MPa. The upper limit of the tensile strength at break (TD) may be 30 MPa, 32 MPa, 35 MPa, or 38 MPa. Here, any lower limit may be used in combination with any upper limit.

[0031] The EVA copolymer relating to this disclosure may have a break elongation (MD) exceeding 450% as measured in a 50 μm thick film according to ASTM D882. The lower limit of the break elongation (MD) may be 450%, 475%, or 500%.

[0032] The EVA copolymer relating to this disclosure may have a break elongation (TD) exceeding 500% as measured in a 50 μm thick film according to ASTM D882. The lower limit of the break elongation (TD) may be 500%, 550%, or 600%.

[0033] The EVA copolymer relating to this disclosure may have a dart drop impact strength (DAT) in the range of 150 to 1200 gF, measured in a 50 μm thick film by ASTM D1709 Method B. The lower limit of the DAT may be 150 gF, 175 gF, or 200 gF. The upper limit of the DAT may be 500 gF, 600 gF, 1000 gF, or 1200 gF. Here, any lower limit can be used in combination with any upper limit.

[0034] The EVA copolymer relating to this disclosure may have an Elmendorf tear strength (MD) exceeding 100 gF, as measured in a 50 μm thick film according to ASTM D1922. The lower limit of the Elmendorf tear strength (MD) may be either 100 gF or 130 gF.

[0035] The EVA copolymer relating to this disclosure may have an Elmendorf tear strength (TD) exceeding 150 gF, as measured in a 50 μm thick film according to ASTM D1922. The lower limit of the Elmendorf tear strength (TD) may be either 150 gF or 190 gF.

[0036] The EVA copolymer relating to this disclosure may have a haze of less than 5% as measured by ASTM D1003 for a 50 μm thick film. The upper limit of the haze may be either 5% or 3%.

[0037] The EVA copolymer relating to this disclosure may have a gloss value exceeding 80 at a 45° angle, as measured by ASTM D2457 for a 50 μm thick film. The lower limit of the gloss value may be either 80 or 90.

[0038] film One or more embodiments of the present disclosure may relate to films that may have a single-layer or multilayer structure. In one or more embodiments, at least one layer of the single-layer or multilayer film may include a blend of linear low-density polyethylene (LLDPE) present in an amount ranging from 30 to 80%, a bio-based EVA copolymer, such as the bio-based EVA copolymer described above, present in an amount ranging from 3 to 65%, low-density polyethylene (LDPE) present in an amount ranging from 15 to 50%, and high-density polyethylene (HDPE) present in an amount ranging from 20 to 40%.

[0039] Multilayer film structure Industrial bags One or more embodiments of this disclosure incorporate the bio-based EVA copolymer described herein into a multilayer film which may have particular applicability in industrial bags, and which may be a co-extruded or laminated multilayer film formed of at least three layers. Bio-based EVA may be added to improve mechanical properties (i.e., as an impact resistance modifier) ​​and adhesion. In one or more embodiments, the multilayer film is - The inner layer contains a blend of LLDPE present in an amount ranging from 30 to 50% by mass of the blend, EVA present in an amount ranging from 0 to 20% by mass of the blend, LDPE present in an amount ranging from 10 to 20% by mass, and HDPE present in an amount ranging from 0 to 40% by mass of the blend. - An outer layer containing a blend of LLDPE present in an amount ranging from 50 to 70% by mass of the blend, EVA present in an amount ranging from 0 to 10% by mass of the blend, and LDPE present in an amount ranging from 40 to 60% by mass of the blend, - An intermediate layer containing a blend of LLDPE present in an amount ranging from 30 to 50% by mass of the blend, EVA present in an amount ranging from 5 to 20% by mass of the blend, LDPE present in an amount ranging from 10 to 20% by mass of the blend, and HDPE present in an amount ranging from 0 to 40% by mass of the blend. It may include, and at least one of the EVAs in the inner layer, outer layer, or intermediate layer is the bio-based EVA described herein.

[0040] food packaging One or more embodiments of this disclosure incorporate the bio-based EVA copolymer described herein into a multilayer film which may have particular applicability in food packaging, and which can be formed, for example, by a double-bubble process of at least five or seven layers. Bio-based EVA may be added to provide shrinkage and adhesion.

[0041] In one or more embodiments, the multilayer film structure may have a thickness of 20 to 120 μm. - The first layer of PE such as LDPE, LLDPE and / or very low-density polyethylene (VLDPE), which can account for 20-40% by mass of the multilayer film. - A second layer containing EVA, which may contain the bio-based EVA copolymer, and which may constitute 10-20% by mass of the multilayer film. - A third layer comprising a barrier polymer selected from polyvinylidene chloride (PVDC), polyamide, and ethylene vinyl alcohol (EVOH), which can constitute 5 to 15% by mass of the multilayer film. - A fourth layer containing EVA, which may contain the bio-based EVA copolymer, and which may constitute 10-20% by mass of the multilayer film. - A fifth layer comprising a sealing material such as LLDPE, VLDPE and / or LDPE, which may constitute 20-40% by mass of the multilayer film. It can include...

[0042] In certain embodiments, the first layer (outermost layer) can form the structure of the film and can be manufactured from LLDPE and / or LDPE having the following properties (film properties measured at a thickness of 50 microns as described above): a density of 0.915 to 0.925 g / cm³ as measured by ASTM D792. 3The melt flow rate measured at 190°C and 2.16 kg according to ASTM D1238 is 0.5 to 3.5 g / 10 min; the tensile strength at break (MD) measured according to ASTM D882 is 20 to 50 MPa; the tensile strength at break (TD) measured according to ASTM D882 is 18 to 50 MPa; the elongation at break (MD) measured according to ASTM D882 is greater than 275%; the elongation at break (TD) measured according to ASTM D882 is in the range of 750% or more; the dirt drop impact measured according to ASTM D1709 is 75 to 1500 g / F50; the Elmendorf tear strength (MD) measured according to ASTM D1922 is greater than 125 gF; the Elmendorf tear strength (TD) measured according to ASTM D1922 is greater than 150 gF. Examples of grades include EB853, EB852 / 72, TN7006, TS7006, Flexus 9212XP, Proxess 1509XP, Proxess 1809, Flexus 9211, Flexus 9200, HF2208S3, HF2207B5, LF0720 / 21AF, LF0720 / 20AF, and LF1020 / 21AF, all of which are commercially available from Braskem.

[0043] The second and fourth layers can be manufactured from a bio-based EVA copolymer, such as the bio-based EVA copolymer described in the paragraph above. The EVA copolymer layer can be responsible for bonding the barrier layer to the outer layer. In certain embodiments, the second and fourth layers are formed from an EVA copolymer composition having a final vinyl acetate content of 12 to 28% by mass. In one or more embodiments, the EVA composition may be a mixture of the bio-based (bio-derived) EVA and petrochemical-derived EVA, and the final vinyl acetate content of the EVA composition is in the range of 12 to 28% by mass of the composition.

[0044] The third layer provides barrier properties and can be manufactured from polymers such as PVDC, polyamide (e.g., nylon), and EVOH.

[0045] In particular, the fifth layer (innermost layer) can be responsible for sealing the film and can be manufactured from LLDPE and / or LDPE having the following characteristics (film characteristics measured at a thickness of 50 microns as described above): a density of 0.905 to 0.925 g / cm³ as measured by ASTM D792. 3 The melt flow rate measured at 190°C and 2.16 kg according to ASTM D1238 is 0.5 to 4.5 g / 10 min; the tensile strength at break (MD) measured according to ASTM D882 is 20 to 50 MPa; the tensile strength at break (TD) measured according to ASTM D882 is 18 to 50 MPa; the elongation at break (MD) measured according to ASTM D882 is greater than 275%; the elongation at break (TD) measured according to ASTM D882 is in the range of 750% or more; the dirt drop impact measured according to ASTM D1709 (A) is 75 to 1500 g / F50; the Elmendorf tear strength (MD) measured according to ASTM D1922 is greater than 125 gF; the Elmendorf tear strength (TD) measured according to ASTM D1922 is greater than 150 gF. Examples of grades include EB853, EB852 / 72, TN7006, TS7006, Flexus 9212XP, Proxess 1509XP, Proxess 1809, Flexus 9211, Flexus 9200, HF2208S3, HF2207B5, LF0720 / 21AF, LF0720 / 20AF and LF1020 / 21AF, and Flexus Cling, all of which are commercially available from Braskem.

[0046] The multilayer structure described above is a five-layer structure, but it is conceivable that a seven-layer structure may also be used. Therefore, in one or more embodiments, the multilayer film may have a thickness of 20 to 120 μm and consist of the following layers: - The first layer of PE such as LDPE and / or LLDPE and / or VLDPE, which can constitute 15-25% by mass of the multilayer film. - A second layer containing EVA, which may contain the bio-based EVA copolymer, and which may constitute 10-20% by mass of the multilayer film. - A third layer including an adhesive layer, which may contain the bio-based EVA copolymer, and which may constitute 10-20% by mass of the multilayer film. - A fourth layer comprising PVDC, polyamide (e.g., nylon) and a barrier polymer such as EVOH, which can constitute 10-20% by mass of the multilayer film. - A fifth layer including an adhesive layer, which may contain the bio-based EVA copolymer, and which may constitute 10-20% by mass of the multilayer film. - A sixth layer containing EVA, which may contain the bio-based EVA copolymer, and which may constitute 10-20% by mass of the multilayer film, and - A seventh layer containing PE such as LLDPE, VLDPE, or mLLDPE, which can account for 15-25% by mass of the multilayer film. It can include...

[0047] In particular, the first layer (outermost layer) can form the structure of the film and can be manufactured from LLDPE and / or LDPE having the following characteristics (film characteristics measured at a thickness of 50 microns as described above): a density of 0.915 to 0.925 g / cm³ as measured by ASTM D792. 3The melt flow rate measured at 190°C and 2.16 kg according to ASTM D1238 is 0.5 to 3.5 g / 10 min; the tensile strength at break (MD) measured according to ASTM D882 is 20 to 50 MPa; the tensile strength at break (TD) measured according to ASTM D882 is 18 to 50 MPa; the elongation at break (MD) measured according to ASTM D882 is greater than 275%; the elongation at break (TD) measured according to ASTM D882 is in the range of 750% or more; the dirt drop impact measured according to ASTM D1709 is 75 to 1500 g / F50; the Elmendorf tear strength (MD) measured according to ASTM D1922 is greater than 125 gF; the Elmendorf tear strength (TD) measured according to ASTM D1922 is greater than 150 gF. Examples of grades include EB853, EB852 / 72, TN7006, TS7006, Flexus 9212XP, Proxess 1509XP, Proxess 1809, Flexus 9211, Flexus 9200, HF2208S3, HF2207B5, LF0720 / 21AF, LF0720 / 20AF, and LF1020 / 21AF, all of which are commercially available from Braskem.

[0048] The second and sixth layers are structural layers that can impart mechanical properties to the film and can be manufactured, for example, from a bio-based EVA copolymer such as the bio-based EVA copolymer described in the paragraph above.

[0049] The third and fifth layers can be responsible for bonding the barrier layer and the intermediate layer, and can be manufactured from a bio-based EVA copolymer, such as the bio-based EVA copolymer described in the paragraph above. In certain embodiments, the EVA in the third and / or fifth layer may have a vinyl acetate content of 12 to 28% by mass of the EVA. In other embodiments, the EVA may be an EVA composition comprising bio-based EVA and petrochemical EVA, wherein the final vinyl acetate content of the EVA composition is in the range of 12 to 28% by mass of the EVA composition.

[0050] The fourth layer provides barrier properties and can be manufactured from polymers such as PVDC, polyamide (e.g., nylon), and EVOH.

[0051] In particular, the seventh layer (innermost layer) can be responsible for sealing the film and can be manufactured from materials such as LLDPE, VLDPE and / or LDPE, having the following characteristics (film characteristics measured at a thickness of 50 microns as described above): a density of 0.905 to 0.925 g / cm³ as measured by ASTM D792. 3 The melt flow rate measured at 190°C and 2.16 kg according to ASTM D1238 is 0.5 to 4.5 g / 10 min; the tensile strength at fracture (MD) measured according to ASTM D882 is 20 to 50 MPa; the tensile strength at fracture (TD) measured according to ASTM D882 is 18 to 50 MPa; the elongation at fracture (MD) measured according to ASTM D882 is greater than 275%; the elongation at fracture (TD) measured according to ASTM D882 is in the range of 750% or more; the dirt drop impact measured according to ASTM D1709 is 75 to 1500 g / F50; the Elmendorf tear strength (MD) measured according to ASTM D1922 is greater than 125 gF; the Elmendorf tear strength (TD) measured according to ASTM D1922 is greater than 150 gF. Examples of grades include EB853, EB852 / 72, TN7006, TS7006, Flexus 9212XP, Proxess 1509XP, Proxess 1809, Flexus 9211, Flexus 9200, HF2208S3, HF2207B5, LF0720 / 21AF, LF0720 / 20AF and LF1020 / 21AF, and Flexus Cling, all of which are commercially available from Braskem.

[0052] In one or more embodiments, the multilayer film may be manufactured from bio-based EVA as described above, treated with electron beam irradiation, then filled with food, and subjected to a heat bath for film shrinkage.

[0053] Food stretch film In another embodiment, a bio-based EVA copolymer can be used to manufacture a food stretch film. This film may have a thickness in the range of 50 to 180 μm and consists of three layers, as detailed below: - The first layer of PE such as LDPE and / or LLDPE, which can constitute 10 to 30% by mass of the multilayer film. - A second layer comprising bio-based EVA and any LLDPE and / or LDPE, etc., which can constitute 40-80% by mass of the multilayer film, and - A third layer of PE such as LDPE and / or LLDPE, which can account for 10 to 30% by mass of the multilayer film. It can have.

[0054] In particular, the first layer (outermost layer) can be responsible for the mechanical properties of the film and can be manufactured from LDPE and / or LLDPE having the following properties (film properties measured at a thickness of 50 microns as described above): a density of 0.915 to 0.925 g / cm³ as measured by ASTM D792. 3The melt flow rate measured at 190°C and 2.16 kg according to ASTM D1238 is 0.5 to 3.5 g / 10 min; the tensile strength at fracture (MD) measured according to ASTM D882 is 20 to 50 MPa; the tensile strength at fracture (TD) measured according to ASTM D882 is 18 to 50 MPa; the elongation at fracture (MD) measured according to ASTM D882 is greater than 275%; the elongation at fracture (TD) measured according to ASTM D882 is in the range of 750% or more; the dirt drop impact measured according to ASTM D1709 is 125 to 1500 g / F50; the Elmendorf tear strength (MD) measured according to ASTM D1922 is greater than 125 gF; the Elmendorf tear strength (TD) measured according to ASTM D1922 is greater than 150 gF. Examples of grades include Flexus 9212XP, Flexus 9211, Flexus 9200, Proxess 1509XP, Proxess1806S3, HF2208S3, HF2207B5, TX7003, TS7003, TN7006, and TS7006, all of which are commercially available from Braskem.

[0055] In particular, the second layer can be responsible for elastic behavior and shape memory, and can be manufactured from a composition comprising the bio-based EVA and, optionally, PE selected from LLDPE and / or LDPE. In one or more embodiments, the bio-based EVA of the intermediate layer may have a vinyl acetate content in the range of 4 to 20% by mass. In one or more embodiments, LDPE and / or LLDPE may be present in an amount of up to 50% by mass of the layer. Examples of LLDPE and LDPE include those having the properties described herein.

[0056] In particular, the third layer (innermost layer) is responsible for the mechanical properties and sealing of the film and can be manufactured from LLDPE and / or LDPE having the following properties (film properties measured at a thickness of 50 microns as described above): density of 0.915~0.925 g / cm³ as measured by ASTM D792. 3The melt flow rate measured at 190°C and 2.16 kg according to ASTM D1238 is 0.5 to 3.5 g / 10 min; the tensile strength at fracture (MD) measured according to ASTM D882 is 20 to 50 MPa; the tensile strength at fracture (TD) measured according to ASTM D882 is 18 to 50 MPa; the elongation at fracture (MD) measured according to ASTM D882 is greater than 275%; the elongation at fracture (TD) measured according to ASTM D882 is in the range of 750% or more; the dirt drop impact measured according to ASTM D1709 is 125 to 1500 g / F50; the Elmendorf tear strength (MD) measured according to ASTM D1922 is greater than 125 gF; the Elmendorf tear strength (TD) measured according to ASTM D1922 is greater than 150 gF. Examples of grades include Flexus 9212XP, Flexus 9211, Flexus 9200, Proxess 1509XP, Proxess1806S3, HF2208S3, HF2207B5, TX7003, TS7003, TN7006, and TS7006, all of which are commercially available from Braskem.

[0057] In one or more embodiments, the hood stretch film may have a maximum force in the range of 5 to 20 N in a puncture resistance test measured according to ASTM D4695.

[0058] In one or more embodiments, the energy at break of the hood stretch film may be in the range of 50 to 300 mJ in a puncture resistance test measured by ASTM D4695.

[0059] In one or more embodiments, the retained force of the food stretch film may be in the range of 5 to 20 N in an elastic recovery test measured by ASTM D5459.

[0060] In one or more embodiments, the residual deformation of the hood stretch film may be in the range of 10–30% in an elastic recovery test measured by ASTM D5459.

[0061] In one or more embodiments, the elastic memory of the food stretch film, as measured by ASTM D5459, may be in the range of 30–200%.

[0062] additives The polymer compositions relating to this disclosure may include fillers and additives that, when added to the polymer composition during blending, modify various physical and chemical properties. Examples of such fillers and additives include one or more polymer additives such as processing aids, lubricants, antistatic agents, clarifying agents, nucleating agents, β-nucleating agents, lubricants, antioxidants, compatibilizers, antacids, light stabilizers such as HALS, infrared absorbers, whitening agents, inorganic fillers, organic dyes and / or inorganic dyes, antiblocking agents, processing aids, flame retardants, plasticizers, biocides, adhesion promoters, metal oxides, mineral fillers, flow promoters, oils, antioxidants, ozone inhibitors, accelerators, and vulcanizing agents.

[0063] Film formation As described above, one or more embodiments of this disclosure may relate to films such as single-layer films and multilayer films. Accordingly, one or more embodiments relate to the process of extruding a bio-based EVA copolymer, including those described above, to form a film. In certain embodiments relating to multilayer structures, the extrusion may include the step of co-extruding bio-based EVA together with at least one other polymer to form a multilayer film. In other embodiments relating to multilayer structures, the extrusion may include the steps of extruding a first layer (including the bio-based EVA described herein), extruding at least one other polymer to form at least one other film layer, and laminating two or more films to form a multilayer film. Furthermore, in one or more embodiments, the extruded film (single-layer or multilayer) may be irradiated with an electron beam.

[0064] Other uses The bio-based EVA described herein can generally be applied to co-extrusion, chilled and frozen food packaging, food packaging, highly transparent films with high mechanical resistance, thermal insulation films for covering agricultural greenhouses, agricultural films, geomembranes, laminated films, sealing layers, stretch films, and injection molded parts.

[0065] While only a few exemplary embodiments have been described above, those skilled in the art will readily understand that many modifications are possible to the exemplary embodiments without substantially departing from the present invention. Accordingly, all such modifications are intended to be included within the scope of this disclosure as set forth in the appended claims. In the claims, means-plus-function claims are intended to encompass not only structural equivalents but also equivalent structures, in addition to the structures described herein, as performing the described function. Thus, although nails and screws are not structural equivalents in that nails employ a cylindrical surface while screws employ a helical surface for fastening multiple wooden parts together, nails and screws can be equivalent structures in the context of fastening multiple wooden parts together. Except where the term “means for” is explicitly used in connection with the relevant function in the claims, it is the express intention of the applicant not to invoke § 112(6) of the United States Patent Act (35 USC) for any limitation of any claim herein.

Claims

1. The use of an ethylene-vinyl acetate copolymer to form at least one layer of a multilayer film, The multilayer film further comprises at least one other film layer containing at least one other polymer, The aforementioned multilayer film has a thickness in the range of 20 to 120 μm. At least a portion of the ethylene is obtained from a bio-based carbon source, and the vinyl acetate is present in the copolymer in an amount ranging from 7 to 20% by mass. The melt index (190°C / 2.16kg) of the copolymer, according to ASTM D1238, is in the range of 0.12 to 8.0 g / 10 min. At least one layer of the multilayer film is (i) an amount exceeding 50% by mass of the blend, in which at least a portion of the ethylene is a copolymer of ethylene and vinyl acetate (EVA) obtained from a bio-based carbon source, (ii) A total amount of linear low-density polyethylene (LLDPE) and low-density polyethylene (LDPE) up to 50% by mass of the blend Uses a blend of the following.

2. The use according to claim 1, wherein at least a portion of the vinyl acetate is obtained from a bio-based carbon source, and / or the bio-based carbon content of the copolymer, as determined by method B of ASTM D6866-18, is at least 50%.

3. The use according to claim 1 or 2, wherein the elongation at break of the copolymer, as determined by ASTM D638 using a 2 mm thick test specimen prepared from a compression-molded sheet according to ASTM D4703, is at least 450%.

4. The use according to any one of claims 1 to 3, wherein the melting point of the copolymer, as determined by ASTM D3418 using a 2 mm thick test specimen made from a compression-molded sheet according to ASTM D4703, is in the range of 75 to 105°C.

5. The use according to any one of claims 1 to 4, wherein the Vicat softening temperature of the copolymer at 10N, as determined by ASTM D1525, is in the range of 58 to 90°C.

6. The use according to any one of claims 1 to 5, wherein the tensile strength at break of the copolymer, as measured in a 50 μm thick film by ASTM D882, is in the range of 25 to 45 MPa in the mechanical direction (MD), and / or the tensile strength at break of the copolymer, as measured in a 50 μm thick film by ASTM D882, is in the range of 18 to 38 MPa in the perpendicular direction (TD).

7. The use according to any one of claims 1 to 6, wherein the elongation at break (MD) of the copolymer, as measured in a 50 μm thick film according to ASTM D882, is greater than 450%, and / or the elongation at break (TD) of the copolymer, as measured in a 50 μm thick film according to ASTM D882, is greater than 500%.

8. The use according to any one of claims 1 to 7, wherein the dirt drop impact strength of the copolymer, as measured on a 50 μm thick film by method B of ASTM D1709, is in the range of 150 to 1200 gF.

9. The use according to any one of claims 1 to 8, wherein the Elmendorf tear strength (MD) of the copolymer, as measured in a 50 μm thick film according to ASTM D1922, is greater than 100 gF, and / or the Elmendorf tear strength (TD) of the copolymer, as measured in a 50 μm thick film according to ASTM D1922, is greater than 150 gF.

10. The use according to any one of claims 1 to 9, wherein the haze of the copolymer, as measured in a 50 μm thick film by ASTM D1003, is less than 5%.

11. A film layer containing at least one copolymer, A film layer comprising at least one other polymer, A multilayer film including, The film layer comprising at least one copolymer is (i) an amount exceeding 50% by mass of the blend, in which at least a portion of the ethylene is a copolymer of ethylene and vinyl acetate (EVA) obtained from a bio-based carbon source, (ii) A total amount of linear low-density polyethylene (LLDPE) and low-density polyethylene (LDPE) up to 50% by mass of the blend A multilayer film containing a blend of these elements.

12. A film layer containing at least one copolymer, A film layer comprising at least one other polymer, A multilayer film including, A multilayer film comprising a film layer containing at least one copolymer, wherein the film layer comprises a blend of LLDPE present in an amount in the range of 30 to 62% by mass, EVA which is a copolymer of ethylene and vinyl acetate obtained from a bio-based carbon source and present in an amount in the range of 3 to 35% by mass, LDPE present in an amount in the range of 15 to 47% by mass, and HDPE present in an amount in the range of 20 to 40% by mass.

13. A film layer containing at least one copolymer, A film layer comprising at least one other polymer, A multilayer film including, - The inner layer contains a blend of LLDPE present in an amount ranging from 30 to 50% by mass of the blend, EVA present in an amount ranging from 0 to 20% by mass of the blend, LDPE present in an amount ranging from 10 to 20% by mass of the blend, and HDPE present in an amount ranging from 0 to 40% by mass of the blend. - An outer layer containing a blend of LLDPE present in an amount ranging from 50 to 60% by mass of the blend, EVA present in an amount ranging from 0 to 10% by mass of the blend, and LDPE present in an amount ranging from 40 to 50% by mass of the blend, - An intermediate layer containing a blend of LLDPE present in an amount ranging from 30 to 50% by mass of the blend, EVA present in an amount ranging from 5 to 20% by mass of the blend, LDPE present in an amount ranging from 10 to 20% by mass of the blend, and HDPE present in an amount ranging from 0 to 40% by mass of the blend. Includes, A multilayer film in which at least one of the inner layer, outer layer, or intermediate layer of EVA is a copolymer of vinyl acetate and ethylene, where at least a portion of the ethylene is obtained from a bio-based carbon source.