Polyethylene resin composition and multilayer film

Abstract

To provide a polyethylene resin composition and a multilayer film capable of obtaining a film having excellent breakage resistance when heated while reducing environmental load.SOLUTION: There is provided a polyethylene resin composition which comprises the following component (A) and component (B), wherein the content of the component (A) is 10 to 90 mass% and the content of the component (B) is 90 to 10 mass% based on 100 mass% of the total amount of the component (A) and (B). The component (A): an ethylene-α-olefin copolymer which satisfies all of the following requirements (a1) to (a3), (a1): the melt mass flow rate (190°C, 2.16 kg) is 0.01 to 50 g / 10 min, (a2): the density is 900 to 935 kg / m3, (a3): the flow activation energy is 50 kJ / mol or more and the component (B): a biomass-derived polyethylene resin (b1) which satisfies the following requirements (b1) and (b2). (b1): the melt flow rate (190°C, 2.16 kg) is 0.1 to 50 g / 10 min and (b2): the density is 900 to 935 kg / m3.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to polyethylene resin compositions and multilayer films. [Background technology]

[0002] Polyethylene resin films are widely used for packaging food, beverages, and other goods. For example, Patent Document 1 describes a film with a density of 908 kg / m³. 3 A sealing layer made of linear low-density polyethylene, with a density of 920 kg / m³. 3 A sealant film laminated with a layer made of linear low-density polyethylene is described as a film having moderate flexibility and excellent impact strength. Furthermore, Patent Document 2 describes a single-layer film made of a resin composition containing a long-chain branched ethylene-α-olefin copolymer and linear low-density polyethylene, and a multilayer film laminated with a layer made of the resin composition and a layer made of linear low-density polyethylene as polyethylene resin films with excellent sealing strength, etc. Patent Document 3 describes a multilayer film laminated with an inner layer and an outer layer made of a long-chain branched ethylene-α-olefin copolymer and an intermediate layer made of linear low-density polyethylene as a film with excellent slipperiness and impact resistance. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 9-137132 [Patent Document 2] Japanese Patent Publication No. 2006-63325 [Patent Document 3] Japanese Patent Publication No. 2017-61122 [Overview of the project] [Problems that the invention aims to solve]

[0004] However, the package formed by heat-sealing the above film does not have sufficient film fracture resistance when heated in a microwave oven or the like, and the film may break. Therefore, a film having sufficient fracture resistance even when heated is desired.

[0005] Furthermore, in recent years, there has been a demand for effectively using carbon resources from the perspective of reducing environmental impact. As part of effectively using carbon resources, materials derived from biomass have attracted attention.

[0006] The present invention has been made in view of such circumstances, and an object thereof is to provide a polyethylene resin composition and a multilayer film capable of obtaining a film that reduces environmental impact and has excellent fracture resistance when heated.

Means for Solving the Problems

[0007] The polyethylene resin composition according to the present invention contains the following component (A) and component (B), and the total amount of component (A) and component (B) is 100% by mass. The content of component (A) is 10 to 90% by mass, and the content of component (B) is 90 to 10% by mass. Component (A): An ethylene-α-olefin copolymer that satisfies all of the following requirements (a1) to (a3). (a1): The melt mass flow rate (190°C, 2.16 kg) is 0.01 to 50 g / 10 minutes (a2): The density is 900 to 935 kg / m 3 (a3): The activation energy of flow is 50 kJ / mol or more Component (B): A biomass-derived polyethylene resin that satisfies the following requirements (b1) and (b2) (b1): The melt mass flow rate (190°C, 2.16 kg) is 0.1 to 50 g / 10 minutes (b2): The density is 900 to 935 kg / m 3

[0008] The multilayer film according to the present invention has an intermediate layer made of the polyethylene resin composition described above, and an inner layer and an outer layer containing polyethylene resin.

[0009] The multilayer film according to the present invention comprises an inner layer made of the above-mentioned polyethylene resin composition, It has an outer layer containing polyethylene resin, The density of the polyethylene resin that makes up the outer layer is 920 kg / m³ 3 The density is higher than that of the polyethylene resin that makes up the inner layer.

[0010] The multilayer film according to the present invention comprises an inner layer made of the above-mentioned polyethylene resin composition, An intermediate layer containing polyethylene resin, It has an outer layer containing polyethylene resin, The density of the polyethylene resin that makes up the intermediate layer is 920 kg / m³ 3 The above conditions are met, and the density is higher than that of the polyethylene resin constituting the inner layer. The density of the polyethylene resin that makes up the outer layer is 920 kg / m³ 3 The following applies: [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a polyethylene resin composition and a multilayer film that can be obtained in which a film with excellent tear resistance when heated can be obtained while reducing the environmental burden. [Brief explanation of the drawing]

[0012] [Figure 1] A diagram showing the shape of the punching die for the dumbbell-shaped test specimen No. 7. [Modes for carrying out the invention]

[0013] The following describes embodiments of the present invention, but the present invention is not limited to the following embodiments.

[0014] [Polyethylene resin composition] The polyethylene resin composition according to this embodiment contains an ethylene-α-olefin copolymer as component (A) and a biomass-derived polyethylene resin as component (B).

[0015] <Ingredient (A)> Component (A), the ethylene-α-olefin copolymer, is an ethylene-α-olefin copolymer obtained by copolymerizing ethylene with an α-olefin having 3 to 20 carbon atoms. Examples of α-olefins having 3 to 20 carbon atoms include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-dodecene, 4-methyl-1-pentene, and 4-methyl-1-hexene, with 1-hexene and 1-octene being preferred. Furthermore, the above α-olefins having 3 to 20 carbon atoms may be used alone or in combination of two or more. Note that component (A) is a copolymer using ethylene derived from fossil fuels and an α-olefin having 3 to 20 carbon atoms as raw materials.

[0016] Examples of the ethylene-α-olefin copolymer that is component (A) include ethylene-propylene copolymer, ethylene-1-butene copolymer, ethylene-1-hexene copolymer, and ethylene-1-octene copolymer, and preferably ethylene-1-butene copolymer, ethylene-1-hexene copolymer, ethylene-1-butene-1-hexene copolymer, and ethylene-1-butene-1-octene copolymer.

[0017] The content of monomer units based on ethylene in component (A), the ethylene-α-olefin copolymer, is typically 50 to 99% by mass relative to the total mass (100% by mass) of the ethylene-α-olefin copolymer. The content of monomer units based on α-olefin is typically 1 to 50% by mass relative to the total mass (100% by mass) of the ethylene-α-olefin copolymer.

[0018] The melt mass flow rate (MFR) of the ethylene-α-olefin copolymer as component (A) is 0.01 to 50 g / 10 min. From the viewpoint of enhancing transparency and extrusion moldability, the MFR is preferably 0.05 g / 10 min or more, more preferably 0.1 g / 10 min or more. Further, from the viewpoint of enhancing fracture resistance, the MFR is preferably 10 g / 10 min or less, more preferably 5 g / 10 min or less. The MFR is measured under the conditions of a temperature of 190 °C and a load of 2.16 kg specified in JIS K7210-1-2014.

[0019] The density of the ethylene-α-olefin copolymer as component (A) is 900 to 935 kg / m 3 It is. From the viewpoint of enhancing transparency and impact resistance, the density is preferably 930 kg / m 3 or less, more preferably 925 kg / m 3 or less. Further, from the viewpoint of enhancing rigidity, the density is preferably 905 kg / m 3 or more, more preferably 910 kg / m 3 or more. The density is measured in accordance with Method A (water substitution method) specified in JIS K7112-199 in using a sample annealed as described in JIS K 6760-1995.

[0020] The ethylene-α-olefin copolymer as component (A) is a polymer having long-chain branches. Such an ethylene-α-olefin copolymer has a higher activation energy for flow (Ea) than a linear ethylene-α-olefin copolymer and is 50 kJ / mol or more. From the viewpoint of further enhancing seal strength and transparency, the Ea is preferably 60 kJ / mol or more, more preferably 70 kJ / mol or more, still more preferably 80 kJ / mol or more. Further, from the viewpoint of further enhancing fracture resistance, the Ea is preferably 110 kJ / mol or less, more preferably 100 kJ / mol or less.

[0021] The activation energy (Ea) of a fluid is a value calculated using the Arrhenius equation from the shift factor (aT) when creating a master curve that shows the dependence of the molten complex viscosity (in Pa·sec) at 190°C on the angular frequency (in rad / sec), based on the temperature-time superposition principle, and is obtained by the method shown below. Specifically, the melt complex viscosity-angular frequency curves (where the unit of melt complex viscosity is Pa·sec and the unit of angular frequency is rad / sec) of the ethylene-α-olefin copolymer at temperatures (T, unit: °C) of 130°C, 150°C, 170°C, and 190°C are superimposed on the melt complex viscosity-angular frequency curve of the ethylene copolymer at 190°C, based on the temperature-time superposition principle. The shift factor (aT) at each temperature (T) is then determined, and a linear approximation equation (Equation (I)) between [ln(aT)] and [1 / (T+273.16)] is calculated using the least squares method from each temperature (T) and the shift factor (aT) at each temperature (T). Next, Ea is determined from the slope m of this linear equation and Equation (II) below.

[0022] ln(aT)=m(1 / (T+273.16))+n (I) Ea = |0.008314 × m| (II)

[0023] aT: Shift Factor Ea: Activation energy of fluid (unit: kJ / mol) T: Temperature (unit: °C) The above calculations may be performed using commercially available calculation software. Examples of such software include TRIOS ver. 5.0.0 (manufactured by TA Instruments).

[0024] The shift factor (aT) is the amount of movement when the log-log curves of molten complex viscosity-angular frequency at each temperature (T) are shifted along the log(Y)=-log(X) axis (where the Y axis represents molten complex viscosity and the X axis represents angular frequency) and superimposed on the molten complex viscosity-angular frequency curve at 190°C. In this superimposition, the log-log curves of molten complex viscosity-angular frequency at each temperature (T) are shifted by aT times for the angular frequency and by 1 / aT times for the molten complex viscosity for each curve. Furthermore, the correlation coefficient when calculating equation (I) using the least squares method from the values ​​at four points: 130°C, 150°C, 170°C, and 190°C is usually 0.99 or higher.

[0025] The molten complex viscosity-angular frequency curve is measured using a viscoelasticity analyzer (e.g., ARES-G2 from TA Instruments, Inc.), typically under the following conditions: geometry: parallel plate, plate diameter: 25 mm, plate spacing: 1.5-2 mm, strain: 5%, angular frequency: 100-0.1 rad / sec. The measurement is performed under a nitrogen atmosphere, and it is preferable to pre-mix the sample with an appropriate amount of antioxidant (e.g., 1000 ppm).

[0026] As a method for producing the ethylene-α-olefin copolymer, which is component (A), known methods can be used. For example, as described in Japanese Patent Publication No. 2006-63325, one method is to copolymerize ethylene with an α-olefin having 3 to 20 carbon atoms in the presence of a catalyst obtained by contacting a co-catalyst support (A) obtained by contacting (a) diethylzinc, (b) fluorinated phenol, (c) water, (d) silica, and (e) trimethyldisilazane (((CH3)3Si)2NH), a crosslinked bisindenyl zirconium complex (B), and an organoaluminum compound (C). Another method is to copolymerize ethylene with an α-olefin having 3 to 20 carbon atoms in the presence of a catalyst obtained by contacting a catalyst for olefin polymerization containing a crosslinked cyclopentadienylindenyl compound (X) containing a transition metal element, a compound (Y) that reacts with the compound of component (X) to produce a cationic metallocene compound, and an inorganic compound support (Z), as described in Japanese Patent Publication No. 2017-61122.

[0027] <Ingredient (B)> Component (B), the biomass-derived polyethylene resin, is a polymer of monomers containing ethylene derived from biomass such as plant residues and food waste. Biomass-derived ethylene can be obtained by known manufacturing methods. Since biomass-derived ethylene is used as the monomer raw material for the polymer, the polymerized polyethylene resin is biomass-derived. Note that the raw material monomer for the polyethylene resin does not have to contain 100% by mass of biomass-derived ethylene. The monomer raw material for the biomass-derived polyethylene resin may contain monomers of ethylene derived from fossil fuels and / or monomers of α-olefins derived from fossil fuels, or it may contain monomers of α-olefins derived from biomass. The α-olefin can usually be an α-olefin having 3 to 20 carbon atoms, preferably butene, hexene, or octene. Furthermore, as the biomass-derived polyethylene resin, ethylene homopolymers, ethylene-α-olefin copolymers may be used individually, or two or more may be used in mixture form. Among these, ethylene-α-olefin copolymers are preferably used.

[0028] Examples of methods for producing biomass-derived ethylene include the method described in International Publication No. 2007 / 055361 or International Publication No. 2008 / 062709, which uses biomass-derived ethanol as a raw material; the method described in International Publication No. 2008 / 67627, which uses the residue of renewable natural raw materials as a raw material; the method described in International Publication No. 2009 / 070858, which uses ethanol produced by fermentation of sugars obtained by extraction and processing of biomass-derived raw materials; and the method described in International Publication No. 2016 / 184893 or International Publication No. 2016 / 184894, which uses thermal cracking of bio-renewable supply materials.

[0029] The biomass content of component (B), biomass-derived polyethylene resin, is radiocarbon ( 14This can be determined by measuring C). Atmospheric carbon dioxide contains, 14 Because it contains a certain percentage (105.5 pMC) of carbon, plants that take in carbon dioxide from the atmosphere to grow, such as corn, 14 It is also known that the carbon content is around 105.5 pMC. And in fossil fuels 14 It is also known that it contains almost no carbon. Therefore, the total carbon atoms in polyethylene resin are 14 By measuring the proportion of C, the biomass content of polyethylene resin can be calculated. 14 The C content is PE[ 14 When set to C, the biomass content of polyethylene resin is PE bio This can be calculated as follows:

[0030] PE bio (%)=PE[ 14 C] / 105.5×100

[0031] Theoretically, if polyethylene resin is made entirely from biomass-derived ethylene, its biomass content will be 100%. Conversely, polyethylene resin produced solely from fossil fuel-derived raw materials will have a biomass content of 0%.

[0032] The biomass content of component (B), the biomass-derived polyethylene resin, is preferably 5% or more, preferably 10% or more, more preferably 15% or more, and even more preferably 20% or more.

[0033] The content of monomer units based on ethylene in the ethylene polymer constituting the biomass-derived polyethylene resin, which is component (B), is usually 50% by mass or more, preferably 70% by mass or more, and more preferably 80% by mass, relative to the total mass (100% by mass) of the ethylene polymer.

[0034] The melt mass flow rate (MFR) of the biomass-derived polyethylene resin, which is component (B), is 0.1 to 50 g / 10 min. From the viewpoint of improving extrusion moldability, the MFR is preferably 0.3 g / 10 min or more, and more preferably 0.5 g / 10 min or more. Furthermore, from the viewpoint of improving impact resistance, the MFR is preferably 10 g / 10 min or less, and more preferably 5 g / 10 min or less. The MFR is measured under the conditions specified in JIS K7210-1-2014, with a temperature of 190°C and a load of 2.16 kg.

[0035] The density of component (B), biomass-derived polyethylene resin, is 900-935 kg / m³. 3 The density is preferably 930 kg / m³ from the viewpoint of improving impact resistance. 3 The following is more preferable: 925 kg / m 3 The following applies. Furthermore, from the viewpoint of increasing rigidity, the density is preferably 905 kg / m³. 3 The above is preferable, and more preferably 910 kg / m 3 This concludes the explanation. The density is measured using a sample that has undergone annealing as described in JIS K 6760-1995, in accordance with Method A (water displacement method) specified in JIS K7112-1999.

[0036] The coefficient of variation (Cx) of the compositional distribution of the biomass-derived polyethylene resin, which is component (B), is preferably 0.5 or higher, and more preferably 0.6 or higher, from the viewpoint of improving fracture resistance during heating. Furthermore, from the viewpoint of improving blocking resistance, Cx is preferably 1 or lower. Here, the coefficient of variation (Cx) of compositional distribution indicates a measure of the compositional distribution, and the larger this value, the wider the compositional distribution. This coefficient of variation (Cx) of compositional distribution is a value defined by the following formula and is calculated from the compositional distribution curve obtained by the temperature-induced elution fractionation method.

[0037] Cx=σ / SCBave

[0038] Cx: Coefficient of variation of the combined component σ: Standard deviation of the composition distribution SCBave: Average value of short-chain branching degree per 1000 carbon atoms (unit: 1 / 1000C)

[0039] As mentioned above, the biomass-derived polyethylene resin, which is component (B), preferably has a broad compositional distribution from the viewpoint of improving its resistance to fracture when heated. In other words, the biomass-derived polyethylene resin contains components other than biomass-derived ethylene. Therefore, the biomass-derived ethylene, which is the raw material for the biomass-derived polyethylene resin, does not need to be purified to the point where it consists only of biomass-derived ethylene during the manufacturing process, and may contain, for example, a monomer of biomass-derived α-olefin.

[0040] Conventionally, in the production of biomass-derived ethylene, significant costs were incurred in purifying only the biomass-derived ethylene. However, as mentioned above, from the viewpoint of improving fracture resistance during heating, the biomass-derived polyethylene resin, which is component (B), may contain components other than biomass-derived ethylene. Therefore, purification only needs to include an appropriate amount of components other than biomass-derived ethylene. Thus, purification costs can be reduced.

[0041] Furthermore, there is no prejudice to using biomass-derived polyethylene resin, which is component (B), that has been purified to contain only biomass-derived ethylene. In that case, in order to achieve the desired Cx value of the biomass-derived polyethylene resin, the raw materials for the biomass-derived polyethylene resin may contain, in addition to biomass-derived ethylene, for example, a monomer of α-olefin derived from biomass or a monomer of α-olefin derived from fossil fuels.

[0042] The biomass-derived polyethylene resin, which is component (B), can be produced by a manufacturing method that includes the step of supplying a raw material containing ethylene derived from biomass to a polymerizer and polymerizing the raw material by a known method.

[0043] Methods for polymerizing ethylene include, for example, polymerization in the presence of a radical initiator. Radical initiators include oxygen-based initiators such as organic peroxides, peroxyesters, dialkyl peroxides, or combinations thereof. Specific examples of radical initiators, though not particularly limited, include t-butylperoxypivalate, di-t-butylperoxide (DTBP), t-butylperoxyacetate (TBPO), t-butylperoxy-2-ethylhexanoate, t-butylperoxyneodecanoate (PND), t-butylperoxyoctoate, and any combination of two or more of these.

[0044] Furthermore, as a method for polymerizing ethylene, methods using known polymerization catalysts such as the Ziegler-Natta catalyst can also be mentioned. As a Ziegler-Natta catalyst, for example, a triethylaluminum-titanium tetrachloride solid composite can be used. The Ziegler-Natta catalyst may be a combination of a titanium trichloride composition obtained by reducing titanium tetrachloride with an organoaluminum compound and further treating it with various electron donors and electron acceptors, an organoaluminum compound, and an aromatic carboxylic acid ester, or a supported catalyst may be formed by contacting magnesium halide with titanium tetrachloride and various electron donors.

[0045] Each Ziegler-Natta catalyst may be used in combination with a specific co-catalyst. Specific examples of co-catalysts include methyl aluminoxane (MAO) and boron-based compounds.

[0046] One method for polymerizing ethylene, when using a radical initiator, is the high-pressure method. In the high-pressure method, ethylene is polymerized under conditions of 1000 to 4000 atmospheres and 100 to 350°C, for example, using a multi-stage gas compressor. Afterwards, residual monomers are separated and the product is obtained by cooling. Low-density polyethylene (LDPE) can be produced by manufacturing ethylene using the high-pressure method.

[0047] When using polymerization catalysts such as Ziegler-Natta catalysts, low-pressure and medium-pressure methods are available for polymerizing ethylene. When using polymerization catalysts, it is preferable to carry out polymerization using either liquid-phase polymerization, gas-phase polymerization, or suspension polymerization. Alternatively, polymerization catalysts may be used to copolymerize ethylene with α-olefins other than ethylene.

[0048] In this embodiment, the content of component (A) and component (B) in the polyethylene resin composition is such that, with the total amount of component (A) and component (B) being 100% by mass, the content of component (A) is 10 to 90% by mass and the content of component (B) is 90 to 10% by mass. If the amount of component (A) is too low (or the amount of component (B) is too high), the fracture resistance when heated may decrease, and if the amount of component (A) is too high (or the amount of component (B) is too low), the fracture resistance when heated may decrease. Preferably, the content of component (A) is 30 to 70% by mass and the content of component (B) is 70 to 30% by mass.

[0049] The polyethylene resin composition according to this embodiment may contain other polymers, additives, etc., in addition to components (A) and (B). Examples of other polymers include high-density polyethylene, linear low-density polyethylene derived from fossil fuels, high-pressure low-density polyethylene derived from fossil fuels, polypropylene resin, elastomers, etc. Examples of additives include antioxidants, anti-blocking agents, lubricants, antistatic agents, dispersants, processability improvers, etc.

[0050] The total content of component (A) and component (B) in the polyethylene resin composition according to this embodiment is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, with the polyethylene resin composition being 100% by mass.

[0051] The polyethylene resin composition according to this embodiment is obtained by melt-kneading component (A), component (B), and other components as needed, using a known method. Known melt-kneading methods include, for example, mixing in a tumble mixer, Henschel mixer, etc., followed by further melt-kneading in a single-screw extruder, multi-screw extruder, etc., or melt-kneading in a kneader, Banbury mixer, etc.

[0052] [Multilayer film] The multilayer film according to this embodiment is a multilayer film having a layer made of the polyethylene resin composition. Examples of layers other than the layer made of the polyethylene resin composition include a layer made of polyolefin resin such as polyethylene resin or polypropylene resin, a layer made of polyester resin such as polyethylene terephthalate or polybutylene terephthalate, a layer made of polyamide resin such as nylon 6 or nylon 66, a layer made of adhesive or adhesive resin, a layer made of cellophane, paper, aluminum foil, etc.

[0053] A suitable example of a multilayer film is a film having an inner layer containing polyethylene resin, an intermediate layer made of the polyethylene resin composition of the present invention, and an outer layer containing polyethylene resin. The density of the polyethylene resin constituting the inner layer is 920 kg / m³. 3 The density is preferably lower than the density of the polyethylene resin constituting the intermediate layer, and is 5 kg / m³ lower than the density of the polyethylene resin constituting the intermediate layer. 3 A density lower than the above is more preferable. Furthermore, the density of the polyethylene resin constituting the outer layer should be 920 kg / m³. 3 The above conditions are met, and it is preferable that the density is higher than that of the polyethylene resin constituting the intermediate layer, and is 5 kg / m³ higher than the density of the polyethylene resin constituting the intermediate layer. 3 A value higher than 10 kg / m² is more preferable. 3 It is even more preferable if the value is higher than the stated value.

[0054] Other suitable examples of multilayer films include films having an inner layer made of the polyethylene resin composition of the present invention and an outer layer containing polyethylene resin. The density of the polyethylene resin constituting the outer layer is 920 kg / m³. 3 The above conditions are preferable, and it is desirable that the density is higher than the density of the polyethylene resin constituting the inner layer, and is 5 kg / m³ higher than the density of the polyethylene resin constituting the inner layer. 3 A value higher than 10 kg / m² is more preferable. 3 It is even more preferable if the value is higher than the stated value.

[0055] Other suitable examples of multilayer films include a film having an inner layer made of the polyethylene resin composition of the present invention, an intermediate layer containing polyethylene resin, and an outer layer containing polyethylene resin. The density of the polyethylene resin constituting the intermediate layer is 920 kg / m³. 3 The above conditions are preferable, and it is desirable that the density is higher than the density of the polyethylene resin constituting the inner layer, and is 5 kg / m³ higher than the density of the polyethylene resin constituting the inner layer. 3 A value higher than 10 kg / m² is more preferable. 3 It is even more preferable that the density is higher than the above. Furthermore, the density of the polyethylene resin constituting the outer layer should be 920 kg / m³. 3 Preferably, it is 915 kg / m 3 The following is more preferable:

[0056] The thickness of the multilayer film according to this embodiment is typically 10 to 100 μm, preferably 20 to 90 μm, and more preferably 30 to 80 μm. In this case, the thickness of the layer made of the polyethylene resin composition is typically 30% or more, and preferably 50% or more.

[0057] Known methods are used for manufacturing multilayer films, such as co-extrusion, dry lamination, wet lamination, sand lamination, and hot melt lamination.

[0058] The multilayer film according to this embodiment is formed into a bag by a known method, such as heat sealing. The bag is used for packaging food, pharmaceuticals, various articles, etc.

[0059] Another embodiment of the present invention is a single-layer film having a layer made of the polyethylene resin composition. As a method for manufacturing the single-layer film, known methods may be used, such as the inflation film molding method or the T die-cast film molding method.

[0060] The polyethylene resin composition and multilayer film according to this embodiment are not limited to the above embodiment, and various modifications are possible without departing from the gist of the disclosure in this application.

[0061] The present invention includes the following embodiments. [1] Contains the following components (A) and (B), with the total amount of components (A) and (B) being 100% by mass, A polyethylene resin composition having a content of 10 to 90% by mass of component (A) and a content of 90 to 10% by mass of component (B). Component (A): Ethylene-α-olefin copolymer that satisfies all of the following requirements (a1) to (a3). (a1): Meltmass flow rate (190℃, 2.16kg) is 0.01~50g / 10min (a2): Density is 900~935kg / m 3 (a3): The activation energy of the flow is 50 kJ / mol or higher. Component (B): Biomass-derived polyethylene resin that satisfies the following requirements (b1) and (b2) (b1): Meltmass flow rate (190℃, 2.16kg) 0.1~50g / 10min (b2): Density of 900-935 kg / m³ 3 [2] The polyethylene resin composition according to [1] above, wherein the coefficient of variation of the compositional distribution of the biomass-derived polyethylene resin of component (B) is 0.5 or more. [3] The melt mass flow rate (190°C, 2.16 kg) of component (A) ethylene-α-olefin copolymer is 0.1 to 5 g / 10 min, and the density is 910 to 925 kg / m³. 3 The polyethylene resin composition described in [1] or [2] above. [4] The melt mass flow rate (190°C, 2.16 kg) of biomass-derived polyethylene resin of component (B) is 0.5 to 5 g / 10 min, and the density is 910 to 925 kg / m³. 3 A polyethylene resin composition as described in any of the above [1] to [3]. [5] A multilayer film having an intermediate layer made of the polyethylene resin composition described in any of [1] to [4] above, and an inner layer and an outer layer containing polyethylene resin. [6] The density of the polyethylene resin that makes up the inner layer is 920 kg / m³ 3 The following, and which is lower than the density of the polyethylene resin constituting the intermediate layer: The density of the polyethylene resin that makes up the outer layer is 920 kg / m³ 3 The multilayer film described above [5], wherein the density is higher than that of the polyethylene resin constituting the intermediate layer. [7] An inner layer made of the polyethylene resin composition described in any of [1] to [4] above, It has an outer layer containing polyethylene resin, The density of the polyethylene resin that makes up the outer layer is 920 kg / m³ 3 The above is true, and the density is higher than that of the polyethylene resin constituting the inner layer. [8] An inner layer made of the polyethylene resin composition described in any of [1] to [4] above, An intermediate layer containing polyethylene resin, It has an outer layer containing polyethylene resin, The density of the polyethylene resin that makes up the intermediate layer is 920 kg / m³ 3 The above conditions are met, and the density is higher than that of the polyethylene resin constituting the inner layer. The density of the polyethylene resin that makes up the outer layer is 920 kg / m³ 3 The following is a multilayer film. [Examples]

[0062] The present invention will be described in more detail below using examples and comparative examples, but the present invention is not limited to the following examples. The measured values ​​for each item in the examples and comparative examples were measured by the method described below.

[0063] (Physical property measurement method) [Meltmass flow rate (MFR, unit: g / 10 min)] Measurements were taken according to JIS K7210-1-2014, using Method A under conditions of 190°C temperature and 2.16 kg load.

[0064] [Density (d, unit: kg / m³) 3 )] After performing the annealing treatment described in JIS K6760-1995, measurements were taken according to Method A (water displacement method) described in JIS K7112-1999.

[0065] [Activation energy of fluid (Ea, unit: kJ / mol)] The molten complex viscosity-angular frequency curves were measured at 130°C, 150°C, 170°C, and 190°C under the following measurement conditions using a viscoelasticity measuring instrument ARES-G2 manufactured by TA Instruments Inc. The samples used for measurement were formed using a press molding machine manufactured by Shinto Metal Industries Co., Ltd. A circular test specimen with a diameter of 25 mm was prepared and used by placing the sample in a 2 mm thick mold and performing the following conditions: preheating temperature 150°C, preheating time 5 minutes, heating temperature 150°C, heating time 2 minutes, heating pressure 5 MPa, cooling temperature 25°C, and cooling time 5 minutes.

[0066] Next, using the analysis software TRIOS ver.5.0.0 (manufactured by TA Instruments Co., Ltd.), a master curve of the molten complex viscosity-angular frequency curve at 190°C was created from the obtained molten complex viscosity-angular frequency curve, and the activation energy (Ea) of the flow was determined.

[0067] ~Measurement Conditions~ Geometry: Parallel Plate Plate diameter: 25mm Plate spacing: 1.5~2mm Strain: 5% Angular frequency: 100~0.1 rad / second Measurement atmosphere: Nitrogen

[0068] [Biomass content] Measurements were taken based on the method described in ASTM D6866.

[0069] [Coefficient of variation in compositional distribution (Cx, unit: -)] Orthodichlorobenzene (ODBC) (with 0.05 w / V dibutylhydroxytoluene added as an antioxidant) was added to the sample, heated and stirred at 145°C for 60 minutes, and filtered through a 2300 mesh wire to prepare the sample solution. 0.5 ml of this sample solution was injected into a temperature-reduced elution (TREF) column (Polymer Char stainless steel microball packed column (3 / 8” o.dx 150 mm)) maintained at 145°C in a cross-fraction chromatograph (Polymer Char CFC), and held for 20 minutes. Next, the TREF column temperature was lowered to 100°C at a rate of 40°C / min and held at 100°C for 20 minutes. Then, the TREF column temperature was lowered to 0°C at a rate of 0.5°C / min and held at 0°C for 30 minutes. Finally, while flowing ODBC through the TREF column at a rate of 1 ml / min, the temperature was raised to 140°C at a rate of 40°C / min, and the relative concentration of the sample eluted from the TREF column during this time was measured using an infrared spectrophotometer (Polymer Char). Measurements were performed using a gel permeation chromatograph (GPC; built into the CFC) equipped with a Char IR5. Three TSKgel GMHHR-H(S)HT 7.8mm ID×300mm columns manufactured by Tosoh Corporation were used for the GPC. Relative concentrations were measured at 5°C increments from 0°C to 50°C, 4°C increments from 50°C to 70°C, 3°C increments from 70°C to 76°C, 2°C increments from 76°C to 100°C, and also at 110°C and 140°C. The results were smoothed using the software included with the CFC and converted to values ​​at 0.5°C increments. Measurements were taken at 2985~2780 cm². -1The area of ​​the absorption peak was used. Using the converted relative concentration, the degree of short-chain branching (SCB) per 1000 carbon atoms of the ethylene-α-olefin copolymer eluted at each temperature was calculated using the following formula (5-1). However, at temperatures where the calculated SCB was negative, no elution was assumed.

[0070] SCB=-0.7322×Elution temperature (℃)+70.68 Formula (5-1)

[0071] From the obtained short-chain branching degree and its relative concentration, a composition distribution curve (x-axis: short-chain branching, y-axis: relative concentration) was obtained. From this curve, the average short-chain branching degree per 1000 carbon atoms (SCBave) and the standard deviation (σ) of the composition distribution were obtained, and the coefficient of variation of the composition distribution Cx, which represents the breadth of the distribution, was calculated from the following equation (5-2).

[0072] Cx=σ / SCBave Equation (5-2)

[0073] Average short-chain branching degree (SCBave) = ΣN(i)·W(i) N(i): Short chain branching degree of the i-th data sampling point W(i): Relative concentration at the i-th data sampling point That is, ΣW(i)=1 Standard deviation of composition distribution (σ) = {Σ(N(i)-SCBave)} 2 ·W(i)} 0.5

[0074] [Tensile breaking strength at 110°C] Using a punching die (Figure 1) for dumbbell-shaped test specimen No. 7 (width of parallel section 2 mm) as described in JIS K 6251-2010, test specimens were punched out from a 50 μm thick film, creating specimens where the longitudinal direction was the pull direction (MD: Machine Direction) and the direction perpendicular to the MD direction (TD: Transverse Direction), respectively. The prepared test specimens were mounted on a tensile testing machine (Shimadzu Corporation AGS-10kNG, maximum load cell load 1 kN) with a grip distance of 20 mm, and conditioned in the attached constant temperature bath at 110°C for 3 minutes. After that, the test specimens were pulled at a tensile speed of 500 mm / min until they broke, and the tensile breaking strength at 110°C was defined as the value (unit: MPa) obtained by dividing the load at the time of breaking by the initial cross-sectional area of ​​the test specimen (i.e., width × thickness of the parallel section in the center of the dumbbell). For each type of film, both MD and TD tests were performed 5 times each, and the average value was calculated.

[0075] (material) A-1: Ethylene-1-butene-1-hexene copolymer, manufactured by Sumitomo Chemical Co., Ltd. Sumikasen (registered trademark) EP GT050 (MFR = 0.3 g / 10 min, density = 922 kg / m³) 3 Activation energy of flow = 82 kJ / mol, Biomass content = 0%)

[0076] B-1: Biomass-derived PE, Braskem SLL118 (LLDPE) (MFR = 1g / 10 min, density = 916 kg / m³) 3 (Activation energy of flow = 39 kJ / mol, Biomass content = 87%, Coefficient of variation of composition distribution = 0.92)

[0077] C-1: Ethylene-1-hexene copolymer, manufactured by Sumitomo Chemical Co., Ltd. Sumikasen (registered trademark) E FV203 (MFR = 2g / 10 min, density = 913 kg / m³) 3 (Activation energy of flow = 34 kJ / mol, Biomass content = 0%, Coefficient of variation of composition distribution = 0.40)

[0078] C-2: Ethylene-1-hexene copolymer, manufactured by Sumitomo Chemical Co., Ltd. Sumikasen (registered trademark) α FZ203-0 (MFR = 2g / 10 min, density = 932 kg / m³) 3 Activation energy of flow = 31 kJ / mol, Biomass content = 0%)

[0079] (Example 1) A three-layer co-extrusion inflation film molding machine (manufactured by Placo Co., Ltd.) equipped with three extruders (all with screw diameters of φ50 mm) and a die with a diameter of φ150 mm and a lip thickness of 2.0 mm was used to form a film with an inner layer, intermediate layer, and outer layer structure. Specifically, material C-1 was supplied to the inner layer extruder and extruded, a composition obtained by mixing 50% by mass of material A-1 and 50% by mass of material B-1 in a tumble mixer (BK-01, manufactured by Stolz Co., Ltd.) was supplied to the intermediate layer extruder and extruded, and material C-2 was supplied to the outer layer extruder and extruded, forming a film with a thickness of 50 μm and a thickness ratio of inner layer / intermediate layer / outer layer = 1 / 3 / 1. The molding conditions were as follows.

[0080] <Molding conditions> • Die setting temperature: 190℃ • Outer cylinder setting temperature: 190℃ • Extrusion conditions for the outer layer: 5-7 kg / hour • Cylinder temperature setting for the intermediate layer: 210℃ • Extrusion conditions for the intermediate layer: 17-19 kg / hour • Processing temperature for the inner layer: 190℃ • Extrusion conditions for the inner layer: 5-7 kg / hour • Blow-up ratio (BUR): 2 • Frost Rindistance (FLD): 230 mm

[0081] The tensile breaking strength at 110°C was measured for the obtained film using the method described above. The results are shown in Table 1.

[0082] (Example 2) A film was formed in the same manner as in Example 1, except that a composition prepared by mixing 70% by mass of material A-1 and 30% by mass of material B-1 in a tumble mixer (BK-01, manufactured by Stolz Co., Ltd.) was supplied to the intermediate layer extruder. The tensile breaking strength of the obtained film at 110°C was measured using the method described above. The results are shown in Table 1.

[0083] (Comparative Example 1) The film was formed in the same manner as in Example 1, except that material C-1 was used instead of material B-1. The tensile breaking strength at 110°C of the obtained film was measured using the method described above. The results are shown in Table 1.

[0084] (Comparative Example 2) The film was formed in the same manner as in Example 2, except that material C-1 was used instead of material B-1. The tensile breaking strength of the obtained film at 110°C was measured using the method described above. The results are shown in Table 1.

[0085] [Table 1]

[0086] The results above demonstrate that the multilayer film using the polyethylene resin composition of the present invention exhibits high tensile breaking strength at 110°C and sufficient resistance to breakage when heated. Furthermore, because biomass-derived polyethylene resin is used, carbon resources can be effectively utilized, reducing the environmental burden.

Claims

1. The following components (A) and (B) are contained, and the total amount of components (A) and (B) is 100% by mass. A polyethylene resin composition having a content of 30 to 70% by mass of component (A) and a content of 70 to 30% by mass of component (B). Component (A): Ethylene-α-olefin copolymer that satisfies all of the following requirements (a1) to (a3). (a1): Meltmass flow rate (190°C, 2.16 kg) 0.1-5 g / 10 min (a2): Density 910-925 kg / m³ ３ (a3): The activation energy of the flow is between 70 kJ / mol and 110 kJ / mol. Component (B): Biomass-derived polyethylene resin that satisfies the following requirements (b1) and (b2) (b1): Meltmass flow rate (190°C, 2.16 kg) 0.5-5 g / 10 min (b2): Density of 910–925 kg / m³ ３

2. The polyethylene resin composition according to claim 1, wherein the coefficient of variation of the compositional distribution of the biomass-derived polyethylene resin of component (B) is 0.6 or more and 1 or less.

3. A multilayer film having an intermediate layer made of the polyethylene resin composition according to claim 1 or 2, and an inner layer and an outer layer containing polyethylene resin.

4. The density of the polyethylene resin that makes up the inner layer is 920 kg / m³ ３ The following, and which is lower than the density of the polyethylene resin constituting the intermediate layer: The density of the polyethylene resin that makes up the outer layer is 920 kg / m³ ３ The multilayer film according to claim 3, wherein the density is higher than that of the polyethylene resin constituting the intermediate layer.

5. An inner layer made of the polyethylene resin composition according to claim 1 or 2, It has an outer layer containing polyethylene resin, The density of the polyethylene resin that makes up the outer layer is 920 kg / m³ ３ The above is true, and the density is higher than that of the polyethylene resin constituting the inner layer.

6. An inner layer made of the polyethylene resin composition according to claim 1 or 2, An intermediate layer containing polyethylene resin, It has an outer layer containing polyethylene resin, The density of the polyethylene resin that makes up the intermediate layer is 920 kg / m³ ３ The above conditions are met, and the density is higher than that of the polyethylene resin constituting the inner layer. The density of the polyethylene resin that makes up the outer layer is 920 kg / m³ ３ The following is a multilayer film.

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