Polyolefin resin film roll

Abstract

[Problem] To provide an environmentally friendly polyolefin resin film roll which has a little variation in the biomass degree among the products and a small number of defects, thereby enabling a packaging material that uses this polyolefin resin film roll to have a low fraction defective and excellent heat seal strength. [Solution] A polyolefin resin film roll which has at least one layer that contains a propylene homopolymer derived from petroleum and / or a propylene-α olefin random copolymer, and a plant-derived linear low-density polyethylene.

Description

Polyolefin resin film roll

[0001] The present invention relates to a polyolefin resin film roll, and also to a roll comprising a laminate of the polyolefin resin film and a biaxially oriented film made of at least one polymer selected from the group consisting of a polyamide resin film, a polyester resin film, and a polypropylene resin film.

[0002] The packaging body is produced by laminating a base film such as a polyamide-based resin film, a polyester-based resin film, or a polypropylene-based resin film with a polyolefin-based resin film or the like as a sealant, and then heat-pressing (hereinafter referred to as heat sealing) the polyolefin-based resin film surfaces together at a temperature close to the melting point of the polyolefin-based resin film while the surfaces of the polyolefin-based resin films are in contact with each other.

[0003] These packages are used to package and transport a variety of foods, including fresh produce, prepared foods, and confectionery. Using packages not only allows food to be delivered to consumers efficiently, but also delays food spoilage, extends expiration dates, and prevents contamination by debris during transportation and storage.

[0004] Polypropylene-based resin films are inexpensive, and packaging materials made from them have excellent heat sealing properties, so they are widely used as heat-sealable films.

[0005] In recent years, there has been a growing demand for a global reduction in carbon dioxide emissions in order to curb global warming. Plastics made from biomass have been attracting attention as a solution. Biomass undergoes photosynthesis from atmospheric carbon dioxide and water. Therefore, even if plant-based plastics are incinerated, they are considered a renewable resource based on the carbon-neutral concept, in that the carbon dioxide that was originally in the atmosphere is simply returned to the atmosphere. While the recycling of food packaging has progressed rapidly in recent years, most of it is still incinerated. Therefore, the use of plant-based plastics for packaging is important from the perspective of protecting the global environment, and various biomass plastics are being considered for use.

[0006] As an example of the use of biomass plastics in polypropylene-based resin films, a technique of adding plant-derived linear low-density polyethylene to polypropylene-based resins is known (see, for example, Patent Document 1). However, there is a problem in that polyethylene has poor compatibility with polypropylene-based resins, resulting in a decrease in heat seal strength.

[0007] Similarly, there is known a technique of adding plant-derived linear low-density polyethylene to a polyolefin resin film (see, for example, Patent Documents 2 and 3). However, there are problems such as variations in the biomass content throughout the product roll, the occurrence of locally weak sealing strength, and an increase in defects.

[0008] Even if plant-derived raw materials are used, if the defect rate increases, it will actually worsen the global environment. Therefore, it can be said that a major challenge is to reduce the defect rate to the same level or higher than when produced from petroleum-derived resins.

[0009] As a method for efficiently adding different raw materials, a masterbatch is known in which a resin component consisting of a polypropylene resin and a low-density polyethylene resin is blended with a filler, wax, etc. However, this technique is insufficient when used as a masterbatch for linear low-density polyethylene because unevenness is likely to occur during molding, and there are also problems with segregation and uneven kneading due to differences in slipperiness between the masterbatch and other raw materials caused by the wax (Patent Document 4, Patent Document 5).

[0010] JP 2021-31563 A JP 2020-75400 A JP 2021-66107 A JP 9-302099 A JP 2003-335869 A

[0011] The present invention aims to provide an environmentally friendly polyolefin resin film roll that has small variations in the biomass content in the product and a small number of defects, resulting in a low reject rate for packaging materials using the film roll and excellent heat seal strength.

[0012] As a result of extensive research to achieve this object, the present inventors have succeeded in suppressing fluctuations in the biomass content of environmentally friendly products and reducing the number of defects by preventing segregation and uneven kneading of raw materials and stably supplying plant-derived linear low-density polyethylene, and have further found that excellent heat-sealing properties can be achieved even when a propylene homopolymer and / or propylene-α-olefin random copolymer and linear low-density polyethylene are used as raw materials, thereby completing the present invention. That is, the present invention has the following aspects.

[0013] [1] A roll made of a polyolefin resin film, the polyolefin resin film having at least one layer satisfying the following a) and the following b): a) containing a petroleum-derived propylene homopolymer and / or a propylene-α-olefin random copolymer, and a plant-derived linear low-density polyethylene, the content of the petroleum-derived propylene homopolymer and / or the propylene-α-olefin random copolymer being 80% by weight or more and 95% by weight or less, and the content of the plant-derived linear low-density polyethylene being 5% by weight or more and 20% by weight or less, relative to the total polyolefin resin constituting the layer; b) the standard deviation of the biomass degree in the longitudinal direction is 0.05% or more and 0.60% or less. The standard deviation is calculated using the following (Equation 1): [2] The petroleum-derived propylene homopolymer and / or propylene-α-olefin random copolymer has an MFR of 2.0 g / 10 min or more and 10.0 g / 10 min or less at 230°C and 2.16 kg, and the plant-derived linear low-density polyethylene has an MFR of 0.8 g / 10 min or more and 5.0 g / 10 min or less at 190°C and 2.16 kg, and a density of 912 kg / m ３ Above, 935kg / m ３[3] The polyolefin resin film roll according to [1], wherein the layer satisfying a) has an antioxidant content of 2,000 ppm to 4,000 ppm relative to the total polyolefin resin composition constituting the layer. [4] The polyolefin resin film roll according to any one of [1] to [3], wherein the layer satisfying a) is present on at least one surface, and the ratio of the thickness of the layer satisfying a) to the thickness of the polyolefin resin film is 23% to 40%. [5] The polyolefin resin film roll according to any one of [1] to [4], wherein the heat-sealing initiation temperature is 110°C to 150°C. [6] A laminate roll comprising a polyolefin resin film and a biaxially oriented film made of at least one polymer selected from the group consisting of a polyester resin film and a polypropylene resin film, wherein the polyolefin resin film has at least one layer satisfying the following a) and also satisfies the following b): a) The polyolefin-based resin layer contains a petroleum-derived propylene homopolymer and / or a propylene-α-olefin random copolymer and a plant-derived linear low-density polyethylene, and the content of the petroleum-derived propylene homopolymer and / or the propylene-α-olefin random copolymer is 80% by weight or more and 95% by weight or less, and the content of the plant-derived linear low-density polyethylene is 5% by weight or more and 20% by weight or less, relative to the entire polyolefin-based resin constituting the layer. b) The standard deviation of the biomass degree in the longitudinal direction is 0.05% or more and 0.60% or less. The standard deviation is calculated using the following formula (1):

[0014] The polyolefin resin film roll of the present invention has small variations in the biomass content within the product and a small number of defects, and is therefore suitable for providing an environmentally friendly polyolefin resin film roll that has a small reject rate for packaging materials using the film roll and excellent heat seal strength.

[0015] Schematic diagram of the raw material system Schematic diagram of the hopper with an inner cone installed External view and projection of cylindrical pellets External view and projection of oval-spherical pellets Measurement points for the standard deviation of biomass content

[0016] (Polyolefin Resin Film) In the polyolefin resin film of the present invention, at least one layer contains petroleum-derived propylene homopolymer and / or propylene-α-olefin random copolymer in an amount of 80% by weight or more and 95% by weight or less, and plant-derived linear low-density polyethylene in an amount of 5% by weight or more and 20% by weight or less, based on the total olefin resin constituting the layer.

[0017] The polyolefin resin composition in the layers other than the at least one layer constituting the polyolefin resin film is primarily composed of a propylene homopolymer and / or a propylene-α-olefin random copolymer from the viewpoint of heat seal strength. Furthermore, from the viewpoint of reducing the environmental impact, it preferably contains a plant-derived linear low-density polyethylene. The propylene homopolymer or propylene-α-olefin random copolymer and the plant-derived linear low-density polyethylene may be used alone or in combination of two or more.

[0018] (Propylene-α-olefin random copolymer) Examples of propylene-α-olefin random copolymers include copolymers of propylene and at least one α-olefin other than propylene having 2 or 4 to 20 carbon atoms. Examples of such α-olefin monomers having 2 or 4 to 20 carbon atoms include ethylene, butene-1, pentene-1, 4-methylpentene-1, hexene-1, and octene-1. For the propylene-α-olefin random copolymer, ethylene is preferred from the viewpoint of heat sealability. At least one type of copolymer is sufficient, and two or more types can be mixed as needed. Particularly preferred is a propylene-ethylene-butene random copolymer in which the primary monomer is propylene and a certain amount of ethylene and butene are copolymerized. In this report, the monomers constituting the random copolymer are listed in descending order of their composition ratio. The propylene-α-olefin random copolymer may be derived from petroleum or plants. Petroleum-derived copolymers are preferred for at least one layer.

[0019] The lower limit of the melt flow rate (MFR) of the propylene-α-olefin random copolymer of the film is preferably 2.0 g / 10 min, more preferably 3.0 g / 10 min, and even more preferably 4.0 g / 10 min. If it is less than the above, the uniformity of the film thickness may be impaired. The upper limit of the melt flow rate of the random copolymer is preferably 10.0 g / 10 min, more preferably 9.0 g / 10 min, and even more preferably 8.0 g / 10 min. If it exceeds the above, problems such as stickiness of the film and poor impact strength (impact strength) of the film may occur.

[0020] Specific examples of the propylene-α-olefin random copolymer include a propylene-ethylene random copolymer (Prime Polypro F-724NPC manufactured by Prime Polymer Co., Ltd., MFR 7.0 g / 10 min at 230°C and a load of 2.16 kg, melting point 142°C), a propylene-ethylene-butene random copolymer (Sumitomo Noblen FL8115A manufactured by Sumitomo Chemical Co., Ltd., MFR 7.0 g / 10 min at 230°C and a load of 2.16 kg, melting point 148°C), a propylene-ethylene-butene random copolymer (Prime Polypro F-794NV manufactured by Prime Polymer Co., Ltd., MFR 5.7 g / 10 min at 230°C and a load of 2.16 kg, melting point 134°C), and a propylene-ethylene-butene random copolymer (Sumitomo Chemical Co., Ltd., MFR 5.7 g / 10 min at 230°C and a load of 2.16 kg, melting point 134°C). Examples include Sumitomo Noblen FL6745A (MFR 6.0 g / 10 min at 230°C and a load of 2.16 kg, melting point 130°C). The content of propylene-α-olefin random copolymer in the polyolefin resin composition constituting the film is preferably 25% by weight or more, more preferably 40% by weight or more, even more preferably 60% by weight or more, and particularly preferably 75% by weight or more, from the viewpoint of heat seal strength. From the viewpoint of flex pinhole resistance, the content is preferably 97% by weight or less, more preferably 90% by weight or less, and even more preferably 85% by weight or less.

[0021] (Propylene homopolymer) In the present invention, the polyolefin resin composition contains a propylene homopolymer, thereby improving heat resistance. The propylene homopolymer used is preferably isotactic polypropylene, which has high crystallinity and suppresses deterioration of the heat shrinkage rate. The propylene homopolymer may be derived from petroleum or plants. The petroleum-derived propylene homopolymer is preferred for at least one layer.

[0022] The lower limit of the melt flow rate (MFR) (measured at 230°C under a load of 2.16 kg) of the propylene homopolymer is preferably 2.0 g / 10 min, more preferably 3.0 g / 10 min, and even more preferably 4.0 g / 10 min. If it is less than the above, the uniformity of the film thickness may be impaired. The upper limit of the melt flow rate of the propylene homopolymer is preferably 10.0 g / 10 min, more preferably 9.0 g / 10 min, and even more preferably 8.0 g / 10 min. The uniformity of the film thickness may be impaired. If it exceeds the above, problems such as stickiness of the film and poor impact strength (impact strength) of the film may occur. A specific example of the propylene homopolymer is propylene homopolymer FLX80E4 (MFR 7.5 g / 10 min, melting point 164°C) manufactured by Sumitomo Chemical. The content of propylene homopolymer in the polyolefin resin composition is preferably 50% by weight or less, more preferably 30% by weight or less, even more preferably 10% by weight or less, and particularly preferably 0% by weight, from the viewpoints of heat seal strength and bag rupture resistance. Since the slipperiness is largely dependent on the amounts of additives such as antiblocking agents and organic lubricants added, adding linear low-density polyethylene to a film does not change the slipperiness much.

[0023] (Plant-derived linear low-density polyethylene) At least one layer of the polyolefin resin composition constituting the film contains plant-derived linear low-density polyethylene in order to reduce environmental impact. Plant-derived linear low-density polyethylene can be produced using ethanol derived from raw materials such as sugarcane or corn, and can be produced by processes such as high-pressure, solution, or gas-phase processes. Examples of suitable copolymers include plant-derived ethylene and at least one α-olefin having 3 or more carbon atoms. As the α-olefin, any α-olefin commonly referred to as an α-olefin may be used, even if it is derived from a fossil fuel. Preferred examples include α-olefins having 3 to 12 carbon atoms, such as propylene, butene-1, hexene-1, octene-1, and 4-methyl-1-pentene. Examples of copolymers of ethylene and α-olefins include ethylene-hexene-1 copolymer, ethylene-butene-1 copolymer, and ethylene-octene-1 copolymer. From the perspective of flex pinhole resistance, ethylene-hexene copolymer is preferred. The lower limit of the plant-derived ethylene content in the plant-derived linear low-density polyethylene is preferably 50%, more preferably 80%. When it is 50% or more, the carbon dioxide reduction effect is good. The upper limit is preferably 98%, more preferably 96%. When it exceeds 98%, the ratio of the α-olefin to be copolymerized decreases, and the heat seal strength decreases.

[0024] The lower limit of the MFR (measured at 190°C and 2.18 kg) of the plant-derived linear low-density polyethylene is preferably 0.8 g / 10 min, more preferably 1.5 g / 10 min. The upper limit is preferably 5.0 g / 10 min, more preferably 4.5 g / 10 min. By keeping the MFR within the above range, good compatibility with polypropylene-based resins can be achieved, and high seal strength can be obtained.

[0025] The lower limit of the density of the plant-derived linear low-density polyethylene is preferably 912 kg / m ３ and more preferably 915 kg / m ３ 912 kg / m ３ By setting the value to 935 kg / m or more, good blocking resistance can be obtained. ３and more preferably 930 kg / m ３ 930 kg / m ３ A specific example is an ethylene-hexene copolymer (plant-derived linear low-density polyethylene) SLH218 (MFR 2.3 g / 10 min, density 916 kg / m) manufactured by Braskem. ３ and a melting point of 126°C). The content of the plant-derived linear low-density polyethylene in the polyolefin resin composition constituting the film is preferably 3% by weight or more, more preferably 12% by weight or more, even more preferably 12% by weight or more, and particularly preferably 15% by weight or more, from the viewpoint of reducing the environmental load. From the viewpoint of heat resistance, the content is preferably 50% by weight or less, more preferably 40% by weight or less, even more preferably 30% by weight or less, and particularly preferably 25% by weight or less.

[0026] (Additives) The polyolefin resin composition constituting the film of the present invention may contain an antiblocking agent. Adding an antiblocking agent to at least one of the outermost layers of the film can improve blocking resistance. The antiblocking agent to be added is not particularly limited, but inorganic particles such as spherical silica, amorphous silica, zeolite, talc, mica, alumina, hydrotalcite, and aluminum borate, and organic particles such as polymethyl methacrylate and ultra-high molecular weight polyethylene can be added. The antiblocking agent contained in the polyolefin resin composition constituting the film is preferably 3000 ppm or less, and more preferably 2500 ppm or less, relative to the polyolefin resin of the layer to which it is added. When the amount is 3000 ppm or less, transparency is good.

[0027] The polyolefin resin composition constituting the film may contain an organic lubricant. This improves the lubrication and anti-blocking effects of the laminated film, improving the film's handling. The reason for this is believed to be that the organic lubricant bleeds out and is present on the film surface, thereby exerting its lubricating and release effects. Organic lubricants preferably have a melting point above room temperature. Examples of organic lubricants include fatty acid amides and fatty acid esters. Specific examples include oleic acid amide, erucic acid amide, behenic acid amide, ethylene bisoleic acid amide, hexamethylene bisoleic acid amide, and ethylene bisoleic acid amide. While these may be used alone, combining two or more types is preferred, as this maintains the lubrication and anti-blocking effects even under harsh environments. The organic lubricant in the polyolefin resin composition is preferably 1500 ppm or less, more preferably 1000 ppm or less, relative to the polyolefin resin. By keeping the concentration at 1500 ppm or less, blocking is less likely to occur even when stored in a location exposed to high temperatures, such as a warehouse in summer. The content is preferably 200 ppm or more, and more preferably 250 ppm or more. By setting the content to 200 ppm or more, good slip properties can be obtained.

[0028] The polyolefin resin composition constituting the film may contain a heat stabilizer. This can suppress defects such as gels that occur when the resin deteriorates due to heat or oxidation during melt extrusion. Commercially available heat stabilizers and antioxidants can be used. Specific examples include BASF's hindered phenol-based antioxidant (Irganox 1010), BASF's phosphite-treated stabilizer (Irgafos 168), and Sumitomo Chemical's phenol-phosphorus-based antioxidant (Sumilizer GP). Heat stabilizers may be used alone or in combination of two or more. While commercially available polyolefin resins are often added during production, they may also be added additionally using a masterbatch or the like. The lower limit of the concentration of the heat stabilizer in the polyolefin resin composition is preferably 1600 ppm or more, more preferably 1800 ppm or more, and more preferably 2000 ppm or more, in total, relative to this layer. If the concentration is below the above range, defects such as gels are likely to occur. The upper limit is preferably 5000 ppm, more preferably 4000 ppm, and even more preferably 3500 ppm in total relative to this layer. If the upper limit is exceeded, the end surface of the film roll may turn red, impairing the appearance.

[0029] The polyolefin resin composition constituting the film may contain, in any layer as needed, an appropriate amount of an antistatic agent, an antifogging agent, a neutralizing agent, a nucleating agent, a colorant, other additives, an inorganic filler, etc., within the scope of the object of the present invention. Examples of neutralizing agents include calcium stearate.

[0030] By adding pellets made from recycled semi-finished products generated during the manufacturing process and finished film products, the resin can be reused without impairing the heat seal strength.

[0031] (Polyolefin Resin Film) The polyolefin resin film of the present invention has at least one layer in which the content of petroleum-derived propylene homopolymer and / or propylene-α-olefin random copolymer is 80% by weight to 95% by weight, and the content of plant-derived linear low-density polyethylene is 5% by weight to 20% by weight, based on the total polyolefin resin constituting the layer. The polyolefin resin film may be a single-layer polyolefin resin film or may contain multiple layers, for example, two, three, or four or more layers. In the case of a two-layer film, it may include a heat-seal layer and a laminate layer. In the case of a three-layer film, it may have a heat-seal layer, a core layer, and a laminate layer in this order. In the case of a four-layer film, it may have a layer containing a polypropylene resin between each of the heat-seal layer, the core layer, and the laminate layer. The heat-seal layer and the laminate layer are layers located on the surface side of the film, and the core layer is located between them. The laminate layer is a layer suitable for bonding a base film such as a biaxially oriented polyamide film, and in practice, it is preferable to laminate it to the base film via an adhesive resin. Printing can also be performed on the laminate layer. The heat-seal layer is a layer suitable for producing a package by overlapping two sheets of the above-mentioned laminate and heat-sealing them so that the polyolefin-based resin film of the resulting laminate is on the inside.

[0032] Furthermore, by using a propylene-α-olefin random copolymer with a low melting point for the heat seal layer and a propylene-α-olefin random copolymer with a high melting point for the layer or laminate layer, it is possible to improve the heat seal strength and heat resistance.

[0033] In the present invention, it is preferable that the surface of the laminate layer of the polyolefin resin film is activated by corona treatment or the like, which not only improves the lamination strength with the base film but also improves printability.

[0034] In the present invention, an example of a polyolefin resin film having a heat-seal layer, a core layer, and a laminate layer in this order will be described in detail below, but is not limited to the following. In this case, the content of petroleum-derived propylene homopolymer and / or a random copolymer of propylene and an α-olefin having 2 or 4 to 20 carbon atoms is 80% by weight to 95% by weight, and the content of plant-derived linear low-density polyethylene is 5% by weight to 20% by weight, based on the entire polyolefin resin constituting at least one layer. In the polyolefin resin film, the content of the plant-derived linear low-density polyethylene in the polyolefin resin composition constituting the core layer is preferably greater than the content of the plant-derived linear low-density polyethylene in the polyolefin resin composition constituting the heat-seal layer, and the content of the plant-derived linear low-density polyethylene in the polyolefin resin composition constituting the laminate layer is preferably greater than the content of the plant-derived linear low-density polyethylene in the polyolefin resin composition constituting the core layer. By doing so, the proportion of polyolefin resin in the resin close to the heat seal surface increases, and high heat seal strength can be obtained.

[0035] (Heat seal layer) The polyolefin resin composition constituting the heat seal layer is composed of a propylene homopolymer and / or a propylene-α-olefin random copolymer from the viewpoint of heat seal strength. The propylene homopolymer and / or the propylene-α-olefin random copolymer may be one type or a mixture of two or more types.

[0036] (Propylene-α-olefin random copolymer) The propylene-α-olefin random copolymer of the heat seal layer can be a copolymer of propylene and at least one α-olefin other than propylene having 2 or 4 to 20 carbon atoms. Examples of such α-olefin monomers having 2 or 4 to 20 carbon atoms include ethylene, butene-1, pentene-1, 4-methylpentene-1, hexene-1, and octene-1. Ethylene is preferably used as the propylene-α-olefin random copolymer from the viewpoint of heat sealability. At least one type of copolymer is sufficient, and two or more types can be mixed and used as needed. Particularly preferred is a propylene-ethylene-butene random copolymer in which propylene is the primary monomer and a certain amount of ethylene and butene are copolymerized. In the present application, the monomers constituting the random copolymer are named and described in descending order of their composition ratio. The propylene-α-olefin random copolymer may be derived from petroleum or plants.

[0037] The lower limit of the melt flow rate (MFR) of the propylene-α-olefin random copolymer is preferably 2.0 g / 10 min, more preferably 3.0 g / 10 min, and even more preferably 4.0 g / 10 min. If it is less than the above, the uniformity of the film thickness may be impaired. The upper limit of the melt flow rate of the random copolymer is preferably 10.0 g / 10 min, more preferably 9.0 g / 10 min, and even more preferably 8.0 g / 10 min. If it exceeds the above, problems such as stickiness of the film and poor impact strength (impact strength) of the film may occur. Specific examples of the propylene-α-olefin random copolymer include a propylene-ethylene random copolymer (Prime Polypro F-724NPC manufactured by Prime Polymer Co., Ltd., MFR 7.0 g / 10 min at 230°C and a load of 2.16 kg, melting point 142°C), a propylene-ethylene-butene random copolymer (Sumitomo Noblen FL8115A manufactured by Sumitomo Chemical Co., Ltd., MFR 7.0 g / 10 min at 230°C and a load of 2.16 kg, melting point 148°C), a propylene-ethylene-butene random copolymer (Prime Polypro F-794NV manufactured by Prime Polymer Co., Ltd., MFR 5.7 g / 10 min at 230°C and a load of 2.16 kg, melting point 134°C), and a propylene-ethylene-butene random copolymer (Sumitomo Chemical Co., Ltd., MFR 5.7 g / 10 min at 230°C and a load of 2.16 kg, melting point 134°C). Sumitomo Noblen FL6745A, MFR 6.0 g / 10 min at 230°C and a load of 2.16 kg, melting point 130°C).

[0038] (Propylene homopolymer) By including a propylene homopolymer in the polyolefin resin composition constituting the heat seal layer, the slipperiness can be improved. The propylene homopolymer to be used is not particularly limited, but isotactic polypropylene is preferred from the viewpoint of blocking resistance. The propylene homopolymer may be derived from petroleum or plants.

[0039] The lower limit of the melt flow rate (MFR) (measured at 230°C under a load of 2.16 kg) of the propylene homopolymer is preferably 2.0 g / 10 min, more preferably 3.0 g / 10 min, and even more preferably 4.0 g / 10 min. If it is less than the above, the uniformity of the film thickness may be impaired. The upper limit of the melt flow rate of the propylene homopolymer is preferably 10.0 g / 10 min, more preferably 9.0 g / 10 min, and even more preferably 8.0 g / 10 min. The uniformity of the film thickness may be impaired. If it exceeds the above, problems such as stickiness of the film and poor impact strength (impact strength) of the film may occur. A specific example of the propylene homopolymer is propylene homopolymer FLX80E4 (MFR 7.5 g / 10 min, melting point 164°C) manufactured by Sumitomo Chemical. In terms of heat seal strength, the content of propylene homopolymer in the polyolefin resin composition constituting the seal layer is preferably 10% by weight or less, more preferably 5% by weight, even more preferably 3% by weight or less, and particularly preferably 0% by weight. If the heat seal layer contains a polyethylene resin such as linear low-density polyethylene, the heat seal strength may decrease due to poor compatibility with the polyethylene resin.

[0040] (Additives) The polyolefin resin composition constituting the heat seal layer may contain an antiblocking agent. While a single type of antiblocking agent may be used, incorporating two or more types of inorganic particles with different particle sizes and shapes can form complex protrusions even on the unevenness of the film surface, thereby achieving a more advanced antiblocking effect. The antiblocking agent to be added is not particularly limited, but inorganic particles such as spherical silica, amorphous silica, zeolite, talc, mica, alumina, hydrotalcite, and aluminum borate, as well as organic particles such as polymethyl methacrylate and ultra-high molecular weight polyethylene, can be added. The antiblocking agent contained in the polyolefin resin composition constituting the heat seal layer is preferably 3000 ppm or less, more preferably 2500 ppm or less, relative to the polyolefin resin of the layer to which it is added. Setting the antiblocking agent to 3000 ppm or less can reduce the detachment of the antiblocking agent. Furthermore, a concentration of 500 ppm or more is preferably 500 ppm or more, more preferably 1000 ppm or more. Setting the concentration to 500 ppm or more can achieve good antiblocking properties.

[0041] The polyolefin resin composition constituting the heat seal layer may contain an organic lubricant. This improves the lubrication and anti-blocking effects of the laminated film, improving the film's handling. The reason for this is believed to be that the organic lubricant bleeds out and is present on the film surface, thereby exerting its lubricating and release effects. Organic lubricants preferably have a melting point above room temperature. Examples of organic lubricants include fatty acid amides and fatty acid esters. Specific examples include oleic acid amide, erucic acid amide, behenic acid amide, ethylene bisoleic acid amide, hexamethylene bisoleic acid amide, and ethylene bisoleic acid amide. While these may be used alone, using two or more of these in combination is preferred, as this maintains the lubrication and anti-blocking effects even in harsh environments. The organic lubricant in the polyolefin resin composition is preferably 1500 ppm or less, more preferably 1000 ppm or less, relative to the polyolefin resin. By keeping the concentration at 1500 ppm or less, blocking is less likely to occur even when stored in a location exposed to high temperatures, such as a warehouse in the summer. The content is preferably 200 ppm or more, and more preferably 250 ppm or more. By setting the content to 200 ppm or more, good slip properties can be obtained.

[0042] The polyolefin resin composition constituting the heat seal layer may contain a heat stabilizer. This can suppress defects such as gels that occur when the resin deteriorates due to heat or oxidation during melt extrusion. Commercially available heat stabilizers and antioxidants can be used. Specific examples include BASF's hindered phenol-based antioxidant (Irganox 1010), BASF's phosphite-treated stabilizer (Irgafos 168), and Sumitomo Chemical's phenol-phosphorus-based antioxidant (Sumilizer GP). A single heat stabilizer may be used, or two or more types may be combined. While commercially available polyolefin resins are often added during production, they may also be added additionally using a masterbatch or the like. The lower limit of the concentration of the heat stabilizer in the polyolefin resin composition, in total, for this layer is preferably 1600 ppm or more, more preferably 1800 ppm or more, and more preferably 2000 ppm or more. If the concentration is below the above range, defects such as gels are likely to occur. The upper limit is preferably 5000 ppm, more preferably 4000 ppm, and even more preferably 3500 ppm in total relative to this layer. If the upper limit is exceeded, the end surface of the film roll may turn red, impairing the appearance.

[0043] The polyolefin resin composition constituting the heat seal layer of the present invention may contain, in any layer as needed, an appropriate amount of an antistatic agent, an antifogging agent, a neutralizing agent, a nucleating agent, a colorant, other additives, an inorganic filler, etc., within the scope of the object of the present invention. Examples of neutralizing agents include calcium stearate.

[0044] (Core Layer) The polyolefin resin composition constituting the core layer is primarily composed of propylene homopolymer and / or propylene-α-olefin random copolymer from the viewpoint of heat seal strength. Furthermore, from the viewpoint of reducing the environmental impact, it preferably contains plant-derived linear low-density polyethylene. The propylene homopolymer or propylene-α-olefin random copolymer and the plant-derived linear low-density polyethylene may be used alone or in combination of two or more.

[0045] (Propylene-α-olefin random copolymer) The propylene-α-olefin random copolymer of the core layer can be a copolymer of propylene and at least one α-olefin other than propylene having 2 or 4 to 20 carbon atoms. Examples of such α-olefin monomers having 2 or 4 to 20 carbon atoms include ethylene, butene-1, pentene-1, 4-methylpentene-1, hexene-1, and octene-1. Ethylene is preferably used as the propylene-α-olefin random copolymer from the viewpoint of heat sealability. At least one type of copolymer is sufficient, and two or more types can be mixed and used as needed. A particularly preferred copolymer is a propylene-ethylene-butene random copolymer in which propylene is the primary monomer and a certain amount of ethylene and butene are copolymerized. In the present application, the monomers constituting the random copolymer are named and described in descending order of their composition ratio. The propylene-α-olefin random copolymer may be derived from petroleum or plants.

[0046] The lower limit of the melt flow rate (MFR) of the propylene-α-olefin random copolymer of the core layer is preferably 2.0 g / 10 min, more preferably 3.0 g / 10 min, and even more preferably 4.0 g / 10 min. If it is less than the above, the uniformity of the film thickness may be impaired. The upper limit of the melt flow rate of the random copolymer is preferably 10.0 g / 10 min, more preferably 9.0 g / 10 min, and even more preferably 8.0 g / 10 min. If it exceeds the above, problems such as stickiness of the film and poor impact strength (impact resistance) of the film may occur. Specific examples of the propylene-α-olefin random copolymer include a propylene-ethylene random copolymer (Prime Polypro F-724NPC manufactured by Prime Polymer Co., Ltd., MFR 7.0 g / 10 min at 230°C and a load of 2.16 kg, melting point 142°C), a propylene-ethylene-butene random copolymer (Sumitomo Noblen FL8115A manufactured by Sumitomo Chemical Co., Ltd., MFR 7.0 g / 10 min at 230°C and a load of 2.16 kg, melting point 148°C), a propylene-ethylene-butene random copolymer (Prime Polypro F-794NV manufactured by Prime Polymer Co., Ltd., MFR 5.7 g / 10 min at 230°C and a load of 2.16 kg, melting point 134°C), and a propylene-ethylene-butene random copolymer (Sumitomo Chemical Co., Ltd., MFR 5.7 g / 10 min at 230°C and a load of 2.16 kg, melting point 134°C). Examples include Sumitomo Noblen FL6745A (MFR 6.0 g / 10 min at 230°C and a load of 2.16 kg, melting point 130°C). The content of the propylene-α-olefin random copolymer in the polyolefin resin composition constituting the core layer is preferably 25% by weight or more, more preferably 40% by weight or more, even more preferably 60% by weight or more, and particularly preferably 75% by weight or more, from the viewpoint of heat seal strength. From the viewpoint of flex pinhole resistance, the content is preferably 97% by weight or less, more preferably 90% by weight or less, and even more preferably 85% by weight or less.

[0047] (Propylene homopolymer) By including a propylene homopolymer in the polyolefin resin composition constituting the laminate layer, heat resistance can be improved. As the propylene homopolymer to be used, isotactic polypropylene is preferred, which has high crystallinity and suppresses deterioration of the heat shrinkage rate. The propylene homopolymer may be derived from petroleum or plants.

[0048] The lower limit of the melt flow rate (MFR) (measured at 230°C under a load of 2.16 kg) of the propylene homopolymer is preferably 2.0 g / 10 min, more preferably 3.0 g / 10 min, and even more preferably 4.0 g / 10 min. If it is less than the above, the uniformity of the film thickness may be impaired. The upper limit of the melt flow rate of the propylene homopolymer is preferably 10.0 g / 10 min, more preferably 9.0 g / 10 min, and even more preferably 8.0 g / 10 min. The uniformity of the film thickness may be impaired. If it exceeds the above, problems such as stickiness of the film and poor impact strength (impact strength) of the film may occur. A specific example of the propylene homopolymer is propylene homopolymer FLX80E4 (MFR 7.5 g / 10 min, melting point 164°C) manufactured by Sumitomo Chemical. The content of propylene homopolymer in the polyolefin resin composition constituting the core layer is preferably 50% by weight or less, more preferably 30% by weight or less, even more preferably 10% by weight or less, and particularly preferably 0% by weight, from the viewpoints of heat seal strength and bag rupture resistance. Since the slip property is largely dependent on the amounts of additives such as antiblocking agents and organic lubricants added, adding linear low-density polyethylene to the core layer does not significantly change the slip property.

[0049] (Plant-derived linear low-density polyethylene) The polyolefin resin composition constituting the core layer preferably contains plant-derived linear low-density polyethylene from the viewpoint of reducing environmental impact. Plant-derived linear low-density polyethylene can be produced using ethanol derived from raw materials such as sugarcane or corn, and can be produced by production methods such as high-pressure methods, solution methods, and gas-phase methods. Examples of suitable α-olefins include copolymers of plant-derived ethylene and at least one α-olefin having 3 or more carbon atoms. As the α-olefin, any α-olefin commonly referred to as an α-olefin may be used, even if it is derived from a fossil fuel. Preferred α-olefins are α-olefins having 3 to 12 carbon atoms, such as propylene, butene-1, hexene-1, octene-1, and 4-methyl-1-pentene. Examples of copolymers of ethylene and α-olefins include ethylene-hexene-1 copolymer, ethylene-butene-1 copolymer, and ethylene-octene-1 copolymer. From the viewpoint of flex pinhole resistance, ethylene-hexene copolymer is preferred. The lower limit of the plant-derived ethylene content in the plant-derived linear low-density polyethylene is preferably 50%, more preferably 80%. When it is 50% or more, the carbon dioxide reduction effect is good. The upper limit is preferably 98%, more preferably 96%. When it exceeds 98%, the ratio of the α-olefin to be copolymerized decreases, and the heat seal strength decreases.

[0050] The lower limit of the MFR (measured at 190°C and 2.18 kg) of the plant-derived linear low-density polyethylene is preferably 0.8 g / 10 min, more preferably 1.5 g / 10 min. The upper limit is preferably 5.0 g / 10 min, more preferably 4.5 g / 10 min. By keeping the MFR within the above range, good compatibility with polyolefin resins can be achieved, and high seal strength can be obtained.

[0051] The lower limit of the density of the plant-derived linear low-density polyethylene is preferably 912 kg / m ３ and more preferably 915 kg / m ３ 910 kg / m ３ By setting the value to 935 kg / m or more, good blocking resistance can be obtained. ３and more preferably 930 kg / m ３ 930 kg / m ３ A specific example is an ethylene-hexene copolymer (plant-derived linear low-density polyethylene) SLH218 (MFR 2.3 g / 10 min, density 916 kg / m) manufactured by Braskem. ３ and a melting point of 126°C). The content of the plant-derived linear low-density polyethylene in the polyolefin resin composition constituting the core layer is preferably 3% by weight or more, more preferably 8% by weight or more, even more preferably 12% by weight or more, and particularly preferably 15% by weight or more, from the viewpoint of reducing the environmental load. From the viewpoint of heat resistance, the content is preferably 50% by weight or less, more preferably 40% by weight or less, even more preferably 30% by weight or less, and particularly preferably 25% by weight or less.

[0052] (Additives) The polyolefin resin composition constituting the core layer may contain an antiblocking agent. The antiblocking agent to be added is not particularly limited, but inorganic particles such as spherical silica, amorphous silica, zeolite, talc, mica, alumina, hydrotalcite, and aluminum borate, and organic particles such as polymethyl methacrylate and ultra-high molecular weight polyethylene can be added. The antiblocking agent contained in the polyolefin resin composition constituting the core layer is preferably 3000 ppm or less, more preferably 2500 ppm or less, even more preferably 1000 ppm or less, and particularly preferably 500 ppm or less, relative to the polyolefin resin of the layer to which it is added. When it is 3000 ppm or less, transparency is good.

[0053] The polyolefin resin composition constituting the core layer may contain an organic lubricant. This improves the lubrication and anti-blocking effects of the laminated film, improving the film's handling. This is believed to be due to the organic lubricant bleeding out and its presence on the film surface, thereby exhibiting its lubricating and release effects. Organic lubricants preferably have a melting point above room temperature. Examples of organic lubricants include fatty acid amides and fatty acid esters. Specific examples include oleic acid amide, erucic acid amide, behenic acid amide, ethylene bisoleic acid amide, hexamethylene bisoleic acid amide, and ethylene bisoleic acid amide. While these may be used alone, combining two or more types is preferred, as this maintains the lubrication and anti-blocking effects even in harsh environments. The organic lubricant in the polyolefin resin composition is preferably 1500 ppm or less, more preferably 1000 ppm or less, relative to the polyolefin resin. By keeping the content at 1500 ppm or less, blocking is less likely to occur even when stored in a location exposed to high temperatures, such as a warehouse in summer. The content is preferably 200 ppm or more, and more preferably 250 ppm or more. By setting the content to 200 ppm or more, good slip properties can be obtained.

[0054] The polyolefin resin composition constituting the core layer may contain a heat stabilizer. This can suppress defects such as gels that occur when the resin deteriorates due to heat or oxidation during melt extrusion. Commercially available heat stabilizers and antioxidants can be used. Specific examples include BASF's hindered phenol-based antioxidant (Irganox 1010), BASF's phosphite-treated stabilizer (Irgafos 168), and Sumitomo Chemical's phenol-phosphorus-based antioxidant (Sumilizer GP). Heat stabilizers may be used alone or in combination of two or more. While commercially available polyolefin resins are often added during production, they may also be added additionally using a masterbatch or the like. The lower limit of the heat stabilizer concentration in the polyolefin resin composition, in total, for this layer is preferably 1600 ppm or more, more preferably 1800 ppm or more, and more preferably 2000 ppm or more. If the concentration is below the above range, defects such as gels are likely to occur. The upper limit is preferably 5000 ppm, more preferably 4000 ppm, and even more preferably 3500 ppm in total relative to this layer. If the upper limit is exceeded, the end surface of the film roll may turn red, impairing the appearance.

[0055] The polyolefin resin composition constituting the core layer may contain, in any layer as needed, an appropriate amount of an antistatic agent, an antifogging agent, a neutralizing agent, a nucleating agent, a colorant, other additives, an inorganic filler, etc., within the scope of the object of the present invention. Examples of neutralizing agents include calcium stearate.

[0056] By adding pellets made from recycled semi-finished products generated during the manufacturing process and finished film to the core layer, the resin can be reused without compromising heat seal strength, thereby reducing the environmental impact.

[0057] (Laminate Layer) The polyolefin resin composition constituting the laminate layer is primarily composed of a propylene homopolymer or a propylene-α-olefin random copolymer from the viewpoint of heat seal strength. Furthermore, it is preferable to include a plant-derived linear low-density polyethylene from the viewpoint of reducing environmental impact. The propylene homopolymer or propylene-α-olefin random copolymer and the plant-derived linear low-density polyethylene may be used alone or in combination of two or more. (Propylene-α-olefin Random Copolymer) The propylene-α-olefin random copolymer constituting the laminate layer may be a copolymer of propylene and at least one α-olefin other than propylene having 2 or 4 to 20 carbon atoms. Examples of such α-olefin monomers having 2 or 4 to 20 carbon atoms include ethylene, butene-1, pentene-1, 4-methylpentene-1, hexene-1, and octene-1. It is preferable to use ethylene as the propylene-α-olefin random copolymer from the viewpoint of heat sealability. Furthermore, at least one type is sufficient, and two or more types can be mixed and used as needed. Particularly suitable are propylene-ethylene-butene random copolymers in which the main monomer is propylene and a certain amount of ethylene and butene are copolymerized. In this report, the random copolymers are named and described in descending order of the monomer composition ratio. Propylene-α-olefin random copolymers may be derived from petroleum or plants.

[0058] The lower limit of the melt flow rate (MFR) of the propylene-α-olefin random copolymer constituting the laminate layer is preferably 2.0 g / 10 min, more preferably 3.0 g / 10 min, and even more preferably 4.0 g / 10 min. If it is less than the above, the uniformity of the film thickness may be impaired. The upper limit of the melt flow rate of the random copolymer is preferably 10.0 g / 10 min, more preferably 9.0 g / 10 min, and even more preferably 8.0 g / 10 min. If it exceeds the above, problems such as stickiness of the film and poor impact strength (impact strength) of the film may occur. Specific examples of the propylene-α-olefin random copolymer include a propylene-ethylene random copolymer (Prime Polypro F-724NPC manufactured by Prime Polymer Co., Ltd., MFR 7.0 g / 10 min at 230°C and a load of 2.16 kg, melting point 142°C), a propylene-ethylene-butene random copolymer (Sumitomo Noblen FL8115A manufactured by Sumitomo Chemical Co., Ltd., MFR 7.0 g / 10 min at 230°C and a load of 2.16 kg, melting point 148°C), a propylene-ethylene-butene random copolymer (Prime Polypro F-794NV manufactured by Prime Polymer Co., Ltd., MFR 5.7 g / 10 min at 230°C and a load of 2.16 kg, melting point 134°C), and a propylene-ethylene-butene random copolymer (Sumitomo Chemical Co., Ltd., MFR 5.7 g / 10 min at 230°C and a load of 2.16 kg, melting point 134°C). Sumitomo Noblen FL6745A, MFR 6.0 g / 10 min at 230°C and a load of 2.16 kg, melting point 130°C. The content of the propylene-α-olefin random copolymer in the polyolefin resin composition constituting the laminate layer is preferably 25% by weight or more, more preferably 40% by weight or more, even more preferably 60% by weight or more, and particularly preferably 75% by weight or more, from the viewpoint of heat seal strength.

[0059] (Propylene homopolymer) By including a propylene homopolymer in the polyolefin resin composition constituting the laminate layer, heat resistance can be improved. As the propylene homopolymer to be used, isotactic polypropylene is preferred, which has high crystallinity and suppresses deterioration of the heat shrinkage rate. The propylene homopolymer may be derived from petroleum or plants.

[0060] The lower limit of the melt flow rate (MFR) (measured at 230°C under a load of 2.16 kg) of the propylene homopolymer is preferably 2.0 g / 10 min, more preferably 3.0 g / 10 min, and even more preferably 4.0 g / 10 min. If the MFR is less than the above range, the uniformity of the film thickness may be impaired. The upper limit of the melt flow rate of the propylene homopolymer is preferably 10.0 g / 10 min, more preferably 9.0 g / 10 min, and even more preferably 8.0 g / 10 min. The uniformity of the film thickness may be impaired. If the MFR exceeds the above range, problems such as stickiness of the film and poor impact strength (impact strength) of the film may occur. The content of the propylene homopolymer in the polyolefin resin composition constituting the laminate layer is not particularly limited, but from the viewpoints of heat seal strength and flex pinhole resistance, it is preferably 50 wt% or less, more preferably 30 wt% or less, even more preferably 10 wt% or less, and particularly preferably 0 wt%.

[0061] (Plant-derived linear low-density polyethylene) The polyolefin resin composition constituting the laminate layer preferably contains plant-derived linear low-density polyethylene, as this improves the environmental load reduction effect. Compared to when plant-derived linear low-density polyethylene is contained only in the core layer, the environmental load reduction effect is dramatically improved by including plant-derived linear low-density polyethylene in the film surface layer as well. The polyolefin resin composition constituting the laminate layer contains plant-derived linear low-density polyethylene from the perspective of reducing the environmental load. Plant-derived linear low-density polyethylene can be produced by a production method such as a high-pressure method, a solution method, or a gas-phase method using ethanol derived from raw materials such as sugarcane or corn. Examples include copolymers of plant-derived ethylene and at least one α-olefin having 3 or more carbon atoms. The α-olefin may be derived from a fossil fuel, as long as it is generally referred to as an α-olefin. It is preferably an α-olefin having 3 to 12 carbon atoms, such as propylene, butene-1, hexene-1, octene-1, or 4-methyl-1-pentene. Examples of copolymers of ethylene and an α-olefin include ethylene-hexene-1 copolymer, ethylene-butene-1 copolymer, and ethylene-octene-1 copolymer. From the viewpoint of pinhole resistance due to bending, an ethylene-hexene copolymer is preferred. The lower limit of the plant-derived ethylene content in the plant-derived linear low-density polyethylene is preferably 50%, more preferably 80%. A content of 50% or more provides a good carbon dioxide reduction effect. The upper limit is preferably 98%, more preferably 96%. Above 98%, the proportion of the α-olefin copolymerized decreases, resulting in a decrease in heat seal strength.

[0062] The lower limit of the MFR (measured at 190°C and 2.18 kg) of the plant-derived linear low-density polyethylene is preferably 0.8 g / 10 min, more preferably 1.5 g / 10 min. The upper limit is preferably 5.0 g / 10 min, more preferably 4.5 g / 10 min. By keeping the MFR within the above range, good compatibility with polypropylene-based resins can be achieved, and high seal strength can be obtained.

[0063] The lower limit of the density of the plant-derived linear low-density polyethylene is preferably 912 kg / m ３ and more preferably 915 kg / m ３ 910 kg / m ３ By setting the value to 935 kg / m or more, good blocking resistance can be obtained. ３ and more preferably 930 kg / m ３ 930 kg / m ３ A specific example is an ethylene-hexene copolymer (plant-derived linear low-density polyethylene) SLH218 (MFR 2.3 g / 10 min, density 916 kg / m) manufactured by Braskem. ３ and a melting point of 126°C). The content of plant-derived linear low-density polyethylene in the polyolefin resin composition constituting the laminate layer is preferably 0% by weight or more, more preferably 3% by weight or more, even more preferably 15% by weight or more, and particularly preferably 20% by weight or more, from the viewpoint of reducing the environmental load. From the viewpoint of heat resistance, it is preferably 50% by weight or less, more preferably 40% by weight or less, and even more preferably 30% by weight or less. Since the amount of additives such as antiblocking agents and organic lubricants added is largely dependent on the amount of additives added, adding linear low-density polyethylene to the laminate layer does not significantly change the slipperiness of the heat-sealable layer.

[0064] The polyolefin resin composition constituting the laminate layer may contain an antiblocking agent. The antiblocking agent to be added is not particularly limited, but inorganic particles such as spherical silica, amorphous silica, zeolite, talc, mica, alumina, hydrotalcite, and aluminum borate, and organic particles such as polymethyl methacrylate and ultra-high molecular weight polyethylene can be added. The antiblocking agent contained in the polyolefin resin composition constituting the laminate layer is preferably 3000 ppm or less, more preferably 2500 ppm or less, even more preferably 1000 ppm or less, and particularly preferably 500 ppm or less, relative to the polyolefin resin of the layer to which it is added.

[0065] The polyolefin resin composition constituting the laminate layer may contain an organic lubricant. This improves the lubrication and anti-blocking effects of the laminate film, improving the film's handleability. The reason for this is believed to be that the organic lubricant bleeds out and is present on the film surface, thereby exerting its lubricating and release effects. Organic lubricants preferably have a melting point above room temperature. Examples of organic lubricants include fatty acid amides and fatty acid esters. Specific examples include oleic acid amide, erucic acid amide, behenic acid amide, ethylene bisoleic acid amide, hexamethylene bisoleic acid amide, and ethylene bisoleic acid amide. While these may be used alone, using two or more of these in combination is preferred, as this maintains the lubrication and anti-blocking effects even in harsh environments. The organic lubricant in the polyolefin resin composition is preferably 1500 ppm or less, more preferably 1000 ppm or less, relative to the polyolefin resin. By keeping the concentration at 1500 ppm or less, blocking is less likely to occur even when stored in a location exposed to high temperatures, such as a warehouse in the summer.

[0066] The polyolefin resin composition constituting the laminate layer may contain a heat stabilizer. This can suppress defects such as gels that occur when the resin deteriorates due to heat or oxidation during melt extrusion. Commercially available heat stabilizers and antioxidants can be used. Specific examples include BASF's hindered phenol-based antioxidant (Irganox 1010), BASF's phosphite-treated stabilizer (Irgafos 168), and Sumitomo Chemical's phenol-phosphorus-based antioxidant (Sumilizer GP). Heat stabilizers may be used alone or in combination of two or more. While commercially available polyolefin resins are often added during production, they may also be added additionally using a masterbatch or the like. The lower limit of the heat stabilizer concentration in the polyolefin resin composition, in total, relative to this layer is preferably 1600 ppm or more, more preferably 1800 ppm or more, more preferably 2000 ppm or more, and even more preferably 2500 ppm or more. If the concentration is below the above range, defects such as gels are likely to occur. The upper limit is preferably 5000 ppm, more preferably 4000 ppm, and even more preferably 3500 ppm in total relative to this layer. If the upper limit is exceeded, the end surface of the film roll may turn red, impairing the appearance.

[0067] The polyolefin resin composition constituting the laminate layer may contain, in any layer as needed, an appropriate amount of an antistatic agent, an antifogging agent, a neutralizing agent, a nucleating agent, a colorant, other additives, an inorganic filler, etc., within the scope of the present invention. Examples of neutralizing agents include calcium stearate.

[0068] The lower limit of the thickness of the polyolefin resin film is preferably 15 μm, more preferably 20 μm, and even more preferably 25 μm. When it is 15 μm or more, heat seal strength is easily obtained. The upper limit of the film thickness is preferably 80 μm, more preferably 70 μm, even more preferably 65 μm, and even more preferably 60 μm. When it is 80 μm or less, the film does not have too much stiffness and is easy to process, and a suitable package can be easily produced.

[0069] The lower limit of the thickness ratio of the heat seal layer of the polyolefin resin film is preferably 23% or more, more preferably 25% or more. By making it 23% or more, the heat seal strength can be increased. The upper limit of the thickness ratio is preferably 40% or less, more preferably 35% or less, and even more preferably 30% or less. If the heat seal layer is 40% or more, the thickness ratio of the core layer and laminate layer containing plant-derived materials becomes relatively small, and the effect of reducing the environmental load is reduced.

[0070] In the polyolefin resin film, the absolute value of the difference in content of the plant-derived linear low-density polyethylene in the polyolefin resin composition constituting the heat-sealable layer and the core layer is not particularly limited, but is preferably 1% by weight or more and 18% by weight or less. The absolute value of the difference in concentration of the linear low-density polyethylene between the heat-sealable layer and the core layer is more preferably 15% by weight or less, even more preferably 10% by weight or less, and particularly preferably 8% by weight or less. By keeping the absolute value of the difference in content 18% by weight or less, it is possible to maintain high interlayer strength at the interface between the heat-sealable layer and the core layer, and to obtain high heat-seal strength.

[0071] In the polyolefin resin film, the absolute value of the difference in the content of the plant-derived linear low-density polyethylene in the polyolefin resin composition constituting the core layer and the laminate layer is preferably 1% by weight or more and 18% by weight or less. The absolute value of the difference in the concentration of linear low-density polyethylene between the core layer and the laminate layer is more preferably 15% by weight or less, even more preferably 10% by weight or less, and particularly preferably 8% by weight or less. By keeping the absolute value of the difference in content 18% by weight or less, high interlayer strength at the interface between the core layer and the laminate layer can be maintained, and high heat seal strength can be obtained.

[0072] (Method for manufacturing polyolefin film roll) Here, specific examples of methods for manufacturing a polyolefin resin laminate film roll having a heat seal layer, a core layer, and a laminate layer in this order will be given, but the present invention is not limited to these. A polyolefin resin laminate film having a heat seal layer, a core layer, and a laminate layer in this order can be obtained by melt-extruding the polyolefin resin compositions constituting each layer using separate extruders, co-extruding the molten resin from a die to form a three-layer structure of the heat seal layer / core layer / laminate layer, and cooling the molten resin sheet with a cooling roll to form an unstretched sheet. For example, in the case of a film in which the core layer of the heat seal layer, core layer, and laminate layer contains 80% by weight or more and 95% by weight or less of petroleum-derived propylene homopolymer and / or propylene-α-olefin random copolymer relative to the total polyolefin resin constituting the layer, and 5% by weight or more and 20% by weight or less of plant-derived linear low-density polyethylene, pellets containing petroleum-derived polypropylene resin and pellets of a masterbatch consisting of a mixture of petroleum-derived polypropylene resin and plant-derived linear low-density polyethylene resin are mixed and then transferred to an extruder for forming the core layer. The reason for this will be described later. The polypropylene resin refers to propylene homopolymer and / or propylene-α-olefin random copolymer. The same process is also performed for films in which the content of petroleum-derived propylene homopolymer and / or random copolymer of propylene and an α-olefin having 2 or 4 to 20 carbon atoms is 80% by weight to 95% by weight, and the content of plant-derived linear low-density polyethylene is 5% by weight to 20% by weight, relative to the total polyolefin resin constituting either the laminate layer, the heat-seal layer, or the single layer. A schematic diagram of the raw material transport and mixing is shown in Figure 1. Upstream of the extruder, pellets containing polypropylene resin, masterbatch pellets consisting of a mixture of polypropylene resin and plant-derived linear low-density polyethylene, recycled pellets, and masterbatch pellets containing additives are individually transferred from raw material hoppers (1) to (4) to a mixing hopper (5).The transfer methods include the slide gate method (1-3), in which the gate opens for a certain time according to the weight of the compound, and the screw feeder method (4), which rotates at a constant speed. After the compound amount for one batch is measured, it is mixed with the stirring blade (7), and is transferred from the mixing hopper to the waiting hopper (9) by a transfer feeder (8) or by gravity, and then transported to the extruder (10) by gravity.

[0073] The upper limit of the weight per weighing batch when the individual raw materials are transferred from the raw material hoppers (1) to (4), weighed, and then transferred to the mixing hopper (5) is preferably 800 kg or less, more preferably 500 kg or less, and even more preferably 300 kg or less. If it is less than 800 kg, fluctuations in the biomass content within the batch can be reduced. The lower limit is preferably 5 kg or more, more preferably 20 kg or more, and even more preferably 100 kg or more. If it is 5 kg or more, productivity is good.

[0074] When transferring from the mixing hopper (5), the smaller the discharge weight per transfer, the less segregation of the blend is preferred. By dividing into smaller containers, segregation can be reduced when the blend is poured into the extrusion hopper. The discharge weight per transfer is preferably 100 kg or less, more preferably 50 kg or less, and even more preferably 25 kg or less. By setting the discharge weight at 100 kg or less, segregation during the melt extrusion process can be reduced.

[0075] (Weight Variation of Raw Materials) The upper limit of the weight variation of the core layer raw materials when producing a film is preferably 3% or less, more preferably 2% or less. At 3% or less, variations in physical properties such as the biomass degree are small, and the number of defects is also small. The upper limit of the weight variation of the laminate layer raw materials when producing a film is preferably 3% or less, more preferably 2% or less. At 3% or less, variations in physical properties such as the biomass degree are small, and the number of defects is also small. The mixing hopper (5) and waiting hopper (9) have cone-shaped lower parts, and the mixed pellets slide down their inclined inner walls and are transferred to the extruder. The angle of the inclined inner walls of each hopper is also preferably 40 degrees or more, more preferably 50 degrees or more, relative to the horizontal. An angle below 40 degrees is undesirable because it impairs the flow of pellets and weakens the segregation prevention effect. Conventionally, when multiple types of raw materials in each hopper are uniformly transferred to a kneading device such as an extruder, an agitator has been installed inside the hopper. However, in order to achieve a more uniform composition in the film, it is preferable to install a segregation prevention device such as an inner cone (Figure 2) inside the hopper from the viewpoints of production stability, prevention of dust generation, etc. Segregation of mixed pellets occurs when some of the mixed raw material pellets have significantly different sliding speeds down the inclined inner wall at the bottom of the hopper, for example, when pellets of a raw material that does not slide easily, such as plant-derived linear low-density polyethylene, as in the conventional case, are blended. This is because the blending ratio of raw material pellets made of petroleum-derived propylene homopolymer and / or random copolymer of propylene and an α-olefin having 2 or 4 to 20 carbon atoms varies between the raw material pellets sliding down along the inner wall and the raw material pellets sliding down near the bottom center of the hopper, i.e., the surface layer of the accumulated raw material pellets.

[0076] Furthermore, if the mixing ratio of pellets with significantly different melt viscosities, such as polypropylene resin and polyethylene resin, fluctuates when they enter the extruder, fluctuations in the resin pressure inside the extruder are likely to occur. Fluctuations in resin pressure are undesirable because they cause gels and other substances that remain in the molten resin path to be discharged, increasing the number of defects in the film. In addition, fluctuations in resin pressure can also cause surging during discharge, which is undesirable.

[0077] Methods for preventing segregation include the following 1) to 4). 1) Feeding raw materials into the extruder before segregation occurs, i.e., mixing the raw materials in small amounts and feeding them into the extruder each time. 2) Preventing differences in the speed at which raw materials slide down the inner wall of the hopper, i.e., making the hopper nearly cylindrical. 3) Using a mixing device, such as a vertically inserted screw, to prevent the raw materials from segregating when they are discharged from the hopper. 4) Installing an inner cone to ensure that all the raw materials fall along the wall and that the materials fall through the hopper without segregation. Of these methods, 1) and 2) have productivity issues due to the small amount of mixed raw materials. Method 3) has the problem of being prone to dust generation due to the continuous mixing of the raw materials. Therefore, method 4) is the most useful industrially.

[0078] A petroleum-derived polypropylene resin and a masterbatch consisting of a mixture of petroleum-derived polypropylene resin and plant-derived linear low-density polyethylene resin are loaded into a raw material hopper as pellets, weighed, and transferred to a mixing hopper (5). After being stirred and mixed in the hopper, the pellets are fed to an extruder via a waiting hopper (9). The upper limit of the angle of repose of the raw material resin pellets is preferably 28 degrees, more preferably 26 degrees. If the angle of repose exceeds this limit, the pellets may remain in the raw material hopper, resulting in fluctuations in the physical properties of the product. The lower limit of the angle of repose of the raw material resin pellets is preferably 20 degrees, more preferably 22 degrees. If the angle of repose is less than this limit, the resin pellets may crumble, causing segregation and resulting in fluctuations in the physical properties of the product. The angle of repose is the maximum inclination angle at which a powder or granular material can be deposited on an inclined surface without sliding. The smaller this value, the easier it is for the particles to slide off. Furthermore, when powders or granular materials with different angles of repose are mixed, segregation is more likely to occur due to the difference in ease of sliding off.

[0079] (Masterbatch containing plant-derived linear low-density polyethylene) Pellets made solely from plant-derived linear low-density polyethylene resin tend to have high friction between resins and with metals, so by creating a masterbatch containing a mixture of polypropylene resin and plant-derived linear low-density polyethylene resin, pellets with a small angle of repose can be obtained. This not only prevents segregation of the plant-derived linear low-density polyethylene resin in the hopper, enabling the production of film rolls with a uniform biomass content, but also reduces the number of defects due to the suppression of resin pressure fluctuations. The polypropylene resin is preferably petroleum-derived.

[0080] The upper limit of the angle of repose of masterbatch pellets made from a mixture of polypropylene-based resin and plant-derived linear low-density polyethylene resin is preferably 28 degrees, more preferably 26 degrees. If the angle of repose exceeds this limit, the pellets may remain in the raw material hopper, and the physical properties or biomass content may be prone to fluctuate within the product. The lower limit of the angle of repose of masterbatch pellets made from a mixture of polypropylene-based resin and plant-derived linear low-density polyethylene resin is preferably 20 degrees, more preferably 22 degrees. If the angle of repose is less than this limit, the resin pellets may be prone to crumble, causing segregation and leading to fluctuations in the physical properties within the product. The polypropylene-based resin is preferably petroleum-derived.

[0081] The shape of the masterbatch pellets may be either cylindrical or elliptical, depending on the granulation method. The pellet size is shown in FIG. 3 for cylindrical pellets and in FIG. 4 for elliptical pellets, with the major axis x, minor axis y, and thickness z, respectively. The upper limit of the length of the major axis x is preferably 6.0 mm or less, more preferably 5.0 mm or less, and even more preferably 4.0 mm or less. The lower limit of the length of the major axis x is preferably 2.5 mm or more, more preferably 2.8 mm or more, and even more preferably 3.0 mm or more. By having the length be 6.0 mm or less or 2.5 mm or more, segregation is less likely to occur when the pellets are discharged from the hopper. The upper limit of the length of the minor axis y is preferably 4.5 mm or less, more preferably 4.0 mm or less, and even more preferably 3.5 mm or less. The lower limit of the length of the minor axis y is preferably 1.5 mm or more, more preferably 1.8 mm or more, and even more preferably 2.0 mm or more. By having the length be 4.5 mm or less or 1.5 mm or more, segregation is less likely to occur when the pellets are discharged from the hopper. The upper limit of the thickness z is preferably 4.5 mm or less, more preferably 4.0 mm or less, and even more preferably 3.5 mm or less. The lower limit of the thickness z is preferably 1.5 mm or more, more preferably 1.8 mm or more, and even more preferably 2.0 mm or more. By making the thickness z 4.5 mm or less or 1.5 mm or more, segregation is less likely to occur when the material is discharged from the hopper.

[0082] The upper limit of the angle of repose of the masterbatch pellets is preferably 28 degrees, more preferably 26 degrees, and even more preferably 25 degrees. The lower limit of the angle of repose of the masterbatch pellets is preferably 20 degrees or more, and more preferably 22 degrees. By setting the angle of repose to 28 degrees or less and 20 degrees or more, segregation is less likely to occur when the masterbatch pellets are discharged from the hopper.

[0083] The lower limit of the density of the masterbatch pellets is preferably 880 kg / cm ３ The lower limit of the density of the masterbatch pellets is preferably 913 kg / cm ３ and more preferably 910 kg / cm ３ 910 kg / cm ３If the density is larger than this, segregation may occur during film production. Generally, the density of polypropylene resin is about 890 kg / cm ３ The closer this value is, the less likely segregation occurs.

[0084] The upper limit of the MFR of the masterbatch pellets at 230°C and a load of 2.16 kg is preferably 8.0 g / 10 min, more preferably 7.0 g / 10 min. The lower limit of the MFR is preferably 1.0 g / 10 min, more preferably 3.0 g / 10 min. If the MFR exceeds 8.0 g / 10 min or is below 1.0 g / 10 min, fluctuations in resin pressure may occur due to differences in viscosity with other polypropylene resins, resulting in surging or an increase in the number of defects.

[0085] The upper limit of the pellet color L of the masterbatch is preferably 90, more preferably 80, and even more preferably 70. The lower limit of the pellet color L is preferably 50, more preferably 55, and even more preferably 60. A value of 90 is sufficient. A value of 50 or higher results in a good film appearance. The upper limit of the pellet color a of the masterbatch is preferably 2.0, more preferably 1.0, and even more preferably 0.0. The lower limit of the pellet color a is preferably -2.0, more preferably -1.5, and even more preferably -1.0. A value of 2.0 or lower is sufficient. A value of 2.0 or lower results in a good film appearance, as the film is not too red and not too blue, and a value of -2.0 or higher results in a good film appearance. The upper limit of the pellet color b of the masterbatch is preferably 2.0, and even more preferably 0.0. The lower limit of the pellet color b is preferably -2.0, more preferably -1.5, and even more preferably -1.0. A value of 2.0 or lower results in a good film appearance, as the film is not too yellow and not too green, and a value of -2.0 or higher results in a good film appearance.

[0086] The lower limit of the content of the plant-derived linear low-density polyethylene constituting the masterbatch relative to the total amount of the polypropylene resin and the plant-derived linear low-density polyethylene is preferably 40% by weight, more preferably 55% by weight. If it is less than this amount, the linear low-density polyethylene cannot be efficiently added to the film, which may result in high costs. The upper limit of the plant-derived linear low-density polyethylene content is preferably 85% by weight, more preferably 75% by weight. If it is less than this amount, it is difficult to reduce the angle of repose of the masterbatch.

[0087] A heat stabilizer can be added when producing the masterbatch. Adding a heat stabilizer can suppress defects such as degradation products that occur during film formation. Commercially available heat stabilizers and antioxidants can be used as heat stabilizers. Specific examples include a hindered phenol-based antioxidant (Irganox 1010) manufactured by BASF, a phosphite-treated stabilizer (Irgafos 168) manufactured by BASF, and a phenol-phosphorus-based antioxidant (Sumilizer GP) manufactured by Sumitomo Chemical Co., Ltd. A single heat stabilizer may be used, or two or more types may be combined. The lower limit of the concentration of the heat stabilizer contained in the masterbatch is preferably 2000 ppm, more preferably 2500 ppm, and even more preferably 3000 ppm. A concentration below the above range may result in defects. The upper limit of the concentration of the heat stabilizer contained in the masterbatch is preferably 5000 ppm, more preferably 4000 ppm. If the temperature exceeds the above range, the end faces of the produced film roll may turn red, which may impair the appearance of the product.

[0088] (Method for producing a masterbatch containing plant-derived linear low-density polyethylene) The plant-derived linear low-density polyethylene and the propylene homopolymer and / or propylene-α-olefin copolymer resin can be mixed using a mixing device, such as a Henschel mixer, super mixer, tumbler mixer, screw blender, or ribbon blender.

[0089] It is preferable to add an antioxidant, which will be described later, to the masterbatch. Commercially available raw materials may already have antioxidants added, but adding them can significantly reduce fisheyes and other problems. This is thought to be because the extrusion temperature of polypropylene resin is higher than the melting point of linear low-density polyethylene, which makes degradation of plant-derived polyethylene resin more likely to progress.

[0090] The antioxidant may be either a primary antioxidant that prevents oxidation by capturing generated radicals, or a secondary antioxidant that prevents oxidation by decomposing generated peroxides. Examples of primary antioxidants include phenol-based antioxidants and amine-based antioxidants, and examples of secondary antioxidants include phosphorus-based antioxidants and sulfur-based antioxidants.

[0091] Examples of phenolic heat stabilizers include Irganox 1010 (manufactured by Ciba Specialty Chemicals, chemical formula: pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]), Irganox 1076 (manufactured by BASF Japan, registered trademark, chemical formula: octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), and Cyanox 1790 (manufactured by Cyanamide, registered trademark, chemical formula: 1,3,5-tris(4-t-butyl-3-hydroxyphenyl)propionate).

[0033] Examples of suitable hydroxybenzoates include N,N'-(hexane-1,6-diyl)bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide], ...

[0092] Examples of phosphorus-based heat stabilizers include Irgafos 168 (Irgafos 168, a registered trademark of BASF Japan, chemical formula: tris(2,4-di-tert-butylphenyl)phosphite), Irgafos 12 (Irgafos 12, a registered trademark of BASF Japan, chemical formula: 6,6',6"-[nitrilotris(ethyleneoxy)]tris(2,4,8,10-tetra-tert-butyldibenzo[d,f ][1,3,2]dioxaphosphepine), Irgafos 38 (Irgafos 38, manufactured by BASF Japan Ltd., registered trademark, chemical formula: bis(2,4-bis(1,1-dimethylethyl)-6-methylphenyl)ethyl ester phosphorous acid), ADK STAB 329K (ADKSTAB329K, manufactured by Asahi Denka Co., Ltd., registered trademark, chemical formula: tris(mono-dinonylphenyl)phosphite), ADK STAB PEP36 (ADKSTAB Examples of such compounds include PEP36 (manufactured by Asahi Denka Co., Ltd., registered trademark, chemical formula name: bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol-di-phosphite), Hostanox P-EPQ (manufactured by Clariant, chemical formula name: tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphonite), GSY-P101 (manufactured by Sakai Chemical Industry Co., Ltd., registered trademark, chemical formula name: tetrakis(2,4-di-tert-butyl-5-methylphenyl)-4,4'-biphenylene diphosphonite), and Sumilizer GP (manufactured by Sumitomo Chemical Co., Ltd., registered trademark, chemical formula name: 6-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-tert-butyldibenz[d,f][1,3,2]-dioxaphosphepine).

[0093] The amount of the antioxidant used in the present invention is not limited, but is preferably in the range of 500 ppm to 5,000 ppm relative to the total amount of the propylene homopolymer and / or propylene-α-olefin copolymer resin and the plant-derived linear low-density polyethylene. Amounts of 1,000 ppm to 4,000 ppm are more preferred, and 1,500 ppm to 3,000 ppm are even more preferred. Amounts of less than 500 ppm are not preferred because the effect of using an antioxidant in combination, described below, is reduced. Conversely, amounts exceeding 5,000 ppm are not preferred because the effect of using an antioxidant in combination, described below, is saturated, and migration of the antioxidant to the film surface can cause film whitening and contamination of cooling rolls during the film-forming process.

[0094] The method for preparing the masterbatch is not particularly limited, and known methods can be used, such as a method of heat-melt kneading using a kneader such as a kneader, a Banbury mixer, or a roll, or a method of heat-melt kneading using a single-screw or twin-screw extruder.

[0095] The melt kneading temperature during masterbatch production is preferably 170° C. or higher and 280° C. or lower, and more preferably 190° C. or higher and 260° C. or lower. By setting the temperature to 170° C. or higher and 260° C. or lower, the thermal history of the resin during masterbatch production can be minimized, and the number of defects such as fish eyes can be reduced. The method for pelletizing the kneaded resin is not particularly limited, and methods such as strand cutting, water-cooled hot cutting, and underwater cutting can be used, but the strand cutting method is preferred because it not only provides high productivity but also reduces fluctuations in physical properties.

[0096] The polyolefin resin film of the present invention can be formed by, for example, an inflation method or a T-die method, but the T-die method is preferred to improve transparency. While the inflation method uses air as a cooling medium, the T-die method uses a cooling roll, making it an advantageous production method for increasing the cooling rate. By increasing the cooling rate, crystallization of the unstretched sheet can be suppressed, resulting in improved transparency. For these reasons, the T-die method is preferred. The width of the T-die is preferably 500 mm or more and 2000 mm or less.

[0097] The lower limit of the melt-kneading temperature is preferably 170°C, more preferably 190°C, and even more preferably 210°C. By setting the temperature to 170°C or higher, the resin can be sufficiently melted and the load on the extruder can be reduced. The upper limit of the melt-kneading temperature is preferably 300°C, more preferably 280°C, and even more preferably 260°C. By setting the temperature to 300°C or lower, thermal degradation of the resin can be reduced and a film with less foreign matter can be produced.

[0098] (Pressure Fluctuation) The pressure fluctuation of the core layer when producing the film is preferably 0.5 MPa or less, more preferably 0.3 MPa or less. If it is 0.5 MPa or less, surging is less likely to occur, the fluctuation in biomass degree in the machine direction is small, and the number of defects is also small. The pressure fluctuation of the laminate layer when producing the film is preferably 0.5 MPa or less, more preferably 0.3 MPa or less. If it is 0.5 MPa or less, surging is less likely to occur, the fluctuation in biomass degree in the machine direction is small, and the number of defects is also small.

[0099] The raw materials for the polyolefin resin compositions for the heat seal layer, core layer, and laminate layer are mixed and melt-mixed and extruded in separate extruders. The molten laminated molten resin films of the seal layer, core layer, and laminate layer are cast from a T-die onto a cooling roll to obtain a non-oriented laminated film. The lower limit of the cooling roll temperature is preferably 15°C, more preferably 20°C. If the temperature is lower than this, condensation may occur on the cooling roll, resulting in insufficient adhesion. The upper limit of the cooling roll temperature is preferably 60°C, more preferably 50°C. If the temperature exceeds this limit, transparency may be impaired. When cooling with the cooling roll, it is preferable to fix both ends of the laminated molten resin film on the cooling roll with an air nozzle or the like, and press the entire width of the laminated molten resin film against the cooling roll with an air knife or the like. Furthermore, it is preferable to simultaneously operate a vacuum chamber to prevent air entrapment between the molten resin sheet and the cooling roll. It is preferable to install the air nozzles on both ends in series in the direction of film travel, and to surround the die with a sheet to prevent wind from hitting the molten resin sheet. It is also preferable to align the direction of the suction port of the vacuum chamber with the traveling direction of the extruded sheet. The edge portions at both ends of the cooled and solidified non-oriented laminated resin film are cut off with a slit blade and introduced into a separate line. The film traveling speed is preferably 30 m / min or more and 50 m / min or less. The surface of the laminate layer of the film is subjected to corona treatment (power density 10 W min / m ２ Above, 30W・min / m ２ The obtained laminated resin film is preferably subjected to a process (described below). The edge portions are trimmed, tension is applied, and the film is wound up onto a roll while being pressed down with a contact roll. After this, aging is preferably carried out at a temperature of 25°C or higher and 50°C or lower for a period of 12 hours to 36 hours. Finally, both ends of the roll are cut again using a slitting machine to obtain a film roll. The width of the film is preferably 400 mm or higher and 1800 m or lower, and the length is preferably 1000 m or higher and 6000 m or lower.

[0100] (Properties of Polyolefin Resin Film) (Average Biomass Degree) The lower limit of the average biomass degree of the polyolefin resin film constituting the present invention is preferably 5%, more preferably 8%, and even more preferably 10%. If it is less than 5%, the effect of reducing the environmental load is small. The upper limit of the biomass degree is preferably 20%, more preferably 17%, and even more preferably 14%. If it exceeds 20%, the seal strength may decrease.

[0101] (Standard Deviation of Biomass Degree) The upper limit of the standard deviation of the biomass degree in the longitudinal direction of the polyolefin resin film roll of the present invention is preferably 0.60%, more preferably 0.50%, and even more preferably 0.40. If it exceeds 0.50%, some of the produced packages are likely to have a low biomass degree. A standard deviation of 0.05% is sufficient. In the measurement of the biomass degree, the standard deviation of the measured values ​​of the biomass degree at all measurement points was calculated using the following (Equation 1).

[0102] (Variation Rate of Biomass Degree in the Longitudinal Direction) The lower limit of the variation rate of biomass degree in the longitudinal direction of the polyolefin resin film roll of the present invention is preferably 2%, more preferably 4%, and even more preferably 6%. 2% is sufficient. The upper limit of the variation rate of biomass degree is preferably 20%, more preferably 15%, and even more preferably 10%. If it exceeds 20%, some of the produced packages are likely to have a low biomass degree. In the measurement of biomass degree, the variation rate was calculated using the measured values ​​of biomass degree at all measurement points. For example, in Example 1, the variation rate of the measured values ​​of biomass degree at 27 points was calculated using the following (Equation 2): Variation rate = (B ｍａｘ -B ｍｉｎ ) / B ａｖｅ [%] (Formula 2) B ａｖｅ Average biomass per 4000 m [%] B ｍａｘ Maximum biomass per 4000 m [%] B ｍｉｎ Minimum biomass per 4000m [%]

[0103] (Haze) The lower limit of the haze of the polyolefin resin film constituting the present invention is preferably 1.0%, more preferably 2.0%, even more preferably 2.5%, and particularly preferably 3.0%. If the haze is 1.0% or more, the film surface is not extremely uneven, making it less likely for blocking to occur inside the package. The upper limit of the haze is preferably 20.0%, more preferably 15.0%, even more preferably 10.0%, and even more preferably 8.0%. If the haze is 20.0% or less, visibility of the package is easily obtained. Linear low-density polyethylene has high crystallinity and is prone to increase in haze, but if added within the above preferred range, the increase in haze can be suppressed.

[0104] (Static friction coefficient) The upper limit of the static friction coefficient of the polyolefin resin film constituting the present invention is preferably 0.70, more preferably 0.50, and even more preferably 0.40. If it is 0.70 or less, the opposite surfaces easily slide against each other when filling the package with food or when opening it, making it easy to open. The lower limit of the static friction coefficient of the film itself is preferably 0.10, more preferably 0.15, even more preferably 0.20, even more preferably 0.25, and particularly preferably 0.30. If it is 0.10 or more, the film roll is less likely to unwind when transported.

[0105] (Young's Modulus) The lower limit of the Young's modulus (longitudinal direction) of the polyolefin resin film constituting the present invention is preferably 200 MPa, more preferably 300 MPa, even more preferably 400 MPa, and even more preferably 500 MPa. If it is less than 200 MPa, the stiffness may be too weak and difficult to process. The upper limit of the Young's modulus (longitudinal direction) is preferably 1000 MPa, more preferably 800 MPa, and even more preferably 750 MPa. A film exceeding 1000 MPa is brittle and may have poor bag-breaking resistance. The lower limit of the Young's modulus (width direction) of the polyolefin resin film constituting the present invention is preferably 200 MPa, more preferably 300 MPa, even more preferably 400 MPa, even more preferably 500 MPa, and particularly preferably 600 MPa. If it is less than 200 MPa, the stiffness may be too weak and difficult to process. The upper limit of the Young's modulus (width direction) is preferably 1000 MPa, more preferably 800 MPa, and even more preferably 750 MPa. A film with a modulus exceeding 1000 MPa is brittle and may have poor bag-breaking resistance. Adding a small amount of linear low-density polyethylene to a polyolefin resin film increases the Young's modulus.

[0106] (Impact Strength) The lower limit of the impact strength of the polyolefin resin film constituting the present invention is preferably 0.20 J, more preferably 0.25 J, and even more preferably 0.30 J. By making it 0.20 J or more, the drop-breakage resistance of the package can be improved. An impact strength of 1.0 J is sufficient. The impact strength is largely dependent on the thickness and molecular orientation of the film. Furthermore, impact strength and drop-breakage resistance do not necessarily correlate.

[0107] (Accelerated Blocking Strength) The lower limit of the accelerated blocking strength of the polyolefin resin film constituting the present invention is preferably 20 mN / 70 mm, more preferably 30 mN / 70 mm, and even more preferably 36 mN / 70 mm. If it is 20 mN / 70 mm or more, the film is likely to have a firm feel. The upper limit of the accelerated blocking strength is preferably 100 mN / 70 mm, more preferably 80 mN / 70 mm, even more preferably 70 mN / 70 mm, and particularly preferably 60 mN / 70 mm. If it is 100 mN / 70 mm or less, blocking is unlikely to occur on the inner surface of the package. If linear low-density polyethylene is added to the core layer and laminate layer, deterioration of the accelerated blocking strength can be suppressed.

[0108] (Puncture Strength) The lower limit of the puncture strength of the polyolefin resin film alone constituting the present invention is preferably 1.0 N, more preferably 1.2 N, even more preferably 1.5 N, and particularly preferably 1.7 N. If it is 1.0 N or more, the laminate has good pinhole resistance. A puncture strength of 5.0 N is extremely excellent, and 3.0 N is sufficient. The puncture strength is highly dependent on the orientation of the film, and therefore does not change much just by changing the resin.

[0109] (Heat seal initiation temperature) The lower limit of the heat seal initiation temperature of the polyolefin resin film constituting the present invention is preferably 110°C, more preferably 120°C. When the temperature is 110°C or higher, the film has a high stiffness and is easy to handle. The upper limit of the heat seal initiation temperature is 150°C, more preferably 140°C, and even more preferably 130°C. When the temperature is 150°C or lower, packages can be produced at high speed, which is economically advantageous. The heat seal initiation temperature is greatly affected by the melting point of the heat seal layer. Therefore, when linear low-density polyethylene is used for the core layer and laminate layer, changes in the heat seal temperature can be suppressed.

[0110] (Film Planar Orientation Coefficient) The lower limit of the planar orientation coefficient of the polyolefin resin film constituting the present invention is preferably 0.000, more preferably 0.001. It is difficult to produce a film with a coefficient below the above limit. The upper limit of the planar orientation of the film is 0.010, more preferably 0.008, and even more preferably 0.006 or less. If it is above the above limit, the film may be stretched non-uniformly, resulting in poor thickness uniformity.

[0111] (Wet tension) The lower limit of the wet tension of the surface of the polyolefin resin film constituting the present invention that is to be laminated with at least one film selected from the group consisting of polyamide resin film, polyester resin film, and polypropylene resin film is preferably 30 mN / m, more preferably 35 mN / m. If it is 30 mN / m or more, the laminate strength is less likely to decrease. The upper limit of the wet tension is preferably 55 mN / m, more preferably 50 mN / m. If it is 55 mN / m or less, blocking between films is less likely to occur when the polyolefin resin film is wound around a roll.

[0112] (Number of Defects) The upper limit of the number of defects in the polyolefin resin film of the present invention within a range of 4000 m in the longitudinal direction and 1000 mm in the transverse direction is preferably 200, more preferably 150, and even more preferably 100. When the number is 200 or less, the appearance of the film is good and the rate of occurrence of defective products is reduced.

[0113] (Configuration and Manufacturing Method of Laminate) The film laminate using the polyolefin resin film constituting the present invention is a laminate in which the polyolefin resin film is used as a sealant and at least one biaxially oriented film selected from the group consisting of polyamide resin films, polyester resin films, and polypropylene resin films. Furthermore, these substrate films may be coated or vapor-deposited using known techniques to impart adhesiveness or barrier properties, or may be further laminated with aluminum foil. Specific examples include biaxially oriented PET (polyethylene terephthalate) film / aluminum foil / sealant, biaxially oriented PET (polyethylene terephthalate) film / biaxially oriented nylon film / sealant, biaxially oriented nylon film / sealant, biaxially oriented polypropylene film / sealant, and biaxially oriented (polyethylene terephthalate) PET film / biaxially oriented nylon film / aluminum foil / sealant. The use of the polyolefin resin film constituting the present invention as a sealant can improve the heat sealability of the laminate. The laminate can be produced by unwinding the polyolefin resin film roll and the biaxially oriented film roll of the present invention and laminating them via an adhesive layer using a known method such as dry lamination or extrusion lamination, but any lamination method may be used. The laminate is preferably stored and transported in the form of a laminate roll. The upper limit of the standard deviation of the biomass degree of the polyolefin resin film in the laminate roll is preferably 0.60%, more preferably 0.50%, and even more preferably 0.40%. If the standard deviation exceeds 0.50%, some of the produced packages are likely to have a low biomass degree. A standard deviation of 0.05% is sufficient. The lower limit of the variation rate of the biomass degree in the longitudinal direction of the polyolefin resin film in the laminate roll is preferably 2%, more preferably 4%, and even more preferably 6%. 2% is sufficient. The upper limit of the variation rate of the biomass degree is preferably 20%, more preferably 15%, and even more preferably 10%.If the content exceeds 20%, the produced packaging tends to contain packaging with a low biomass content.

[0114] The properties of the laminate will now be described. (Heat seal strength) The lower limit of the heat seal strength of the laminate of the present invention is preferably 20 N / 15 mm, more preferably 22 N / 15 mm. If it is 20 N / 15 mm or more, bag rupture resistance is likely to be obtained. A heat seal strength of 60 N / 15 mm is very excellent, and 35 N / 15 mm is sufficient.

[0115] (Puncture Strength) The lower limit of the puncture strength of the laminate of the present invention is preferably 7N, more preferably 8N, and even more preferably 9N. If it is 7N or more, pinholes are less likely to occur when the protrusions come into contact with the packaging material. The upper limit of the puncture strength is preferably 45N, more preferably 30N, and even more preferably 15N. If it is 45N or less, the laminate does not feel too stiff and is easy to handle. Since the puncture strength is highly dependent on the orientation of the film, it does not change much just by changing the resin.

[0116] (Packaging) The polyolefin resin film or laminate arranged to wrap around the contents, such as food, for the purpose of protecting the contents from natural dust, gas, etc., is called a packaging. The packaging is produced by cutting out the polyolefin resin film or laminate, bonding the inner surfaces together using a heated heat seal bar or ultrasonic waves, etc., to form a bag. For example, four-sided sealed bags, in which two rectangular sheets are stacked with the heat seal layer side facing inward and the four sides are heat-sealed, or back-sealed packaging bags are widely used. The contents may be food, but may also be other products such as daily necessities, and the shape of the packaging may be a shape other than a rectangle, such as a stand-up pouch or pillow packaging.

[0117] The present invention will be described in detail below with reference to examples, but is not limited to these. The properties obtained in each example were measured and evaluated by the following methods. In the evaluation, the flow direction of the film in the film production process was defined as the longitudinal direction, and the direction perpendicular to the flow direction was defined as the width direction.

[0118] (1) Resin Density The density was evaluated in accordance with JIS K7112:1999 D Method (density gradient pipe). N=3 measurements were made, and the average value was calculated.

[0119] (2) Melt flow rate (MFR) Based on JIS K-7210-1, measurements were carried out at 230°C and a load of 2.16 kg for polypropylene resins and at 190°C and a load of 2.16 kg for plant-derived linear low-density polyethylene. N=3 measurements were made, and the average value was calculated.

[0120] (3) Melting Point The melting point was determined as the temperature of the maximum melting peak in the DSC curve of the resin obtained using a Shimadzu Differential Scanning Calorimeter DSC-60 manufactured by Shimadzu Corporation. The starting temperature was 30°C, the heating rate was 5°C / min, and the end temperature was 180°C. N=3 measurements were made, and the average value was calculated.

[0121] (4) Biomass Degree Based on the ASTM D6866 Biobased Test, the biomass degree was calculated from the C14 (carbon atom with a mass number of 14) concentration in the film. Sampling was performed by removing a film 2 m from the edge of the surface layer of the film roll, and then further sampling from the film 2 m away at positions every 500 m from the surface layer to the core in the longitudinal direction, as well as at the center of the film roll, 100 mm inward from the left edge, and 100 mm inward from the right edge in the width direction. The average biomass degree of all measurement positions was calculated. For example, in Example 1, sampling was performed on a 1000 mm wide, 4000 m long film roll at 27 locations: 9 rows every 500 m from the surface layer to the core in the longitudinal direction, and the center of the roll and three rows at 400 mm on each side in the width direction. The average value of the measurements at these 27 locations was calculated (Figure 5).

[0122] (5) Standard Deviation of Biomass Degree in the Longitudinal Direction In the measurement of biomass degree described above, the standard deviation of the measured values ​​of biomass degree at all measurement points was calculated using the following (Equation 1).

[0123] (6) Variation Rate of Biomass Degree in the Longitudinal Direction In the measurement of biomass degree, the variation rate was calculated using the measured values ​​of biomass degree at all measurement points. For example, in Example 1, the variation rate of the measured values ​​of biomass degree at 27 points was calculated using the following formula (2). Variation Rate = (B ｍａｘ -B ｍｉｎ ) / B ａｖｅ [%]...(Formula 2) B ａｖｅ Average biomass per 4000 m [%] B ｍａｘ Maximum biomass per 4000 m [%] B ｍｉｎ Minimum biomass per 4000m [%]

[0124] (7) Haze Haze was measured according to JIS K 7136. Measurement was made on three polyolefin resin films before lamination, and the average value was calculated.

[0125] (8) Static Friction Coefficient The seal layer sides of the films were overlapped, and the static friction coefficient was measured using a universal tensile tester STM-T-50BP (manufactured by Toyo Baldwin) in accordance with JIS K 7125. Samples were cut out to a size of 200 mm in the longitudinal direction and 80 mm in the transverse direction, and measurements were performed using the following three methods.

[0126] (9) Young's modulus The tensile strength in the longitudinal direction and the width direction was measured at 23°C in accordance with JIS-K7127. The test piece had a length of 150 mm and a width of 15 mm, and the test speed was 200 mm / min. N=3 measurements were made, and the average value was calculated.

[0127] (10) Impact Resistance (Impact Strength) Measurement was carried out at 23° C. using a film impact tester manufactured by Toyo Seiki Seisakusho.

[0128] (11) Accelerated Blocking Strength A polyolefin resin film was cut into a length of 148 mm in the longitudinal direction and 105 mm in the width direction. The film was stacked with the sealing surfaces facing each other. After preheating for 30 minutes in a 50°C environment, the film was sandwiched between 7.0 cm square aluminum plates maintained at 50°C. Using a Mini Test Press MP-SCH manufactured by Toyo Seiki Seisakusho Co., Ltd., the aluminum plate and the sample were pressed at 50°C and 100 kN and maintained for 15 minutes. The removed sample was cut into a width of 70 mm. The stacked sample was opened 30 mm, and a 3 mm diameter metal rod was inserted parallel to the width direction. The sample was mounted on an Autograph AG-I manufactured by Shimadzu Corporation, and the load applied when the metal rod was moved in the longitudinal direction at 200 mm / min was measured. Measurements were performed with N = 3, and the average value was calculated.

[0129] (12) Puncture Strength The puncture strength of the polyolefin resin film and the laminate was measured at 23°C in accordance with "2. Test Method for Strength, etc." in "Specifications and Standards for Foods, Food Additives, etc., Part 3: Apparatus and Containers / Packaging" (Ministry of Health and Welfare Notification No. 20, 1982) under the Food Sanitation Act. A needle with a tip diameter of 0.7 mm was pierced into the film at a puncture speed of 50 mm / min, and the strength at which the needle penetrated the film was measured. N=3 measurements were made, and the average value was calculated.

[0130] (13) Heat-sealing initiation temperature The heat-sealing initiation temperature of polyolefin resin films was measured in accordance with JIS Z 1713 (2009). The films were cut into rectangular test pieces (for heat sealing) measuring 50 mm x 250 mm (width direction x length direction of the film). The seal layer portions of two test pieces were overlapped, and a thermal gradient tester (heat-sealing tester) manufactured by Toyo Seiki Seisakusho Co., Ltd. was used. The heat-sealing pressure was 0.2 MPa and the heat-sealing time was 1.0 sec. The test pieces were then heat-sealed under conditions of increasing temperature in 5°C increments. After heat-sealing, test pieces were cut into 15 mm widths. The heat-sealed test pieces were opened 180°, and the unsealed portion was clamped with a zipper to peel off the sealed portion. The temperature at which the heat-sealing strength reached 4.9 N was then determined. The tester used was a universal material testing machine 5965 manufactured by Instron Instruments. The test speed was 200 mm / min. Measurements were made with N=5, and the average value was calculated.

[0131] (14) Plane Orientation Coefficient The density was evaluated in accordance with JIS K0062:1999, a method for measuring refractive index of chemical products. Measurements were made with N=3, and the average value was calculated. The plane orientation coefficient was calculated using the following formula: Plane orientation coefficient = (Nx + Ny) / 2 - Nz Nx: Refractive index in the longitudinal direction Ny: Refractive index in the width direction Nz: Refractive index in the thickness direction

[0132] (15) Wet Tension The wet tension of the laminate layer surface was measured in accordance with JIS-K6768 Plastics - Films and Sheets - Wet Tension Test Method.

[0133] (16) Heat-sealing strength The heat-sealing conditions and strength measurement conditions were as follows. The polyolefin resin film sides of the laminates obtained in the Examples and Comparative Examples were overlapped and heat-sealed for 1 second at a pressure of 0.2 MPa with a seal bar width of 10 mm and a heat-sealing temperature of 160°C, followed by cooling. Test pieces measuring 80 mm in the longitudinal direction and 15 mm in the transverse direction were cut from the films heat-sealed at each temperature, and the peel strength of each test piece was measured when the heat-sealed portion was peeled at a crosshead speed of 200 mm / min. The test machine used was a Universal Testing Machine 5965 manufactured by Instron Instruments. Measurements were performed three times for each test, and the average value was calculated.

[0134] (17) Number of Defects For a film roll measuring 4000 m in the longitudinal direction and 1000 mm in the transverse direction, the number of defects having a length of 0.3 mm or more and 1.0 mm or less was counted using a defect detector, MaxEye. X320, manufactured by Hutec Co., Ltd. Three rolls (n = 3) were inspected and the average value was calculated.

[0135] (18) Pellet Size Pellets were randomly sampled, and the lengths of the long side x, short side y, and thickness z shown in Figures 1 and 2 were measured with a vernier caliper. Measurements were performed on n = 10 samples, and the average values ​​were calculated.

[0136] (19) Angle of repose Pellets were piled up using a funnel on a horizontally placed disk-shaped tray with a diameter of 10 cm. When the pellets spilled out of the tray and the piled up pellets formed a certain mound, the inclination angle of the mound was measured with a protractor. Measurements were taken for every quarter circle, and the average value was calculated.

[0137] (20) Pellet Color: Using a colorimeter manufactured by Nippon Denshoku Industries Co., Ltd., the colors X, Y, and Z were measured in accordance with JIS Z-8722, and then the colors L, a, and b were calculated. Measurements were made with n=3, and the average values ​​were calculated.

[0138] (21) Raw Material Weighing Fluctuations The raw material weighing ratios in the core layer and laminate layer weighing lines were monitored. The absolute value of the maximum difference from the set ratios in Tables 2 and 3 was taken as the weighing fluctuation value.

[0139] (22) Pressure Fluctuation The pressure before the die at the melt lines of the core layer and the laminate layer was monitored at intervals of 1 second for 60 minutes. The difference between the maximum and minimum pressure values ​​within the 60-minute range was calculated and used as the pressure fluctuation value.

[0140] (Production of Masterbatch) The following raw materials were used for the masterbatch: Propylene-ethylene-butene random copolymer FL8115A (MFR 7.0 g / 10 min, melting point 148°C) manufactured by Sumitomo Chemical Co., Ltd. Propylene-ethylene random copolymer FG3DC (MFR 9.5 g / 10 min, melting point 148°C) manufactured by Nippon Polypropylene Co., Ltd. Ethylene-hexene copolymer (plant-derived linear low-density polyethylene) SLH218 (MFR 2.3 g / 10 min, density 916 kg / m) manufactured by Braskem Co., Ltd. ３ , melting point 126°C)

[0141] (Masterbatches: MB1 to MB6, MB8) Polypropylene resin and plant-derived linear low-density polyethylene pellets were added to a 200 kg capacity tumbler mixer in the raw material ratios of the masterbatches MB1 to MB6 and MB8 listed in Table 1. A heat stabilizer was added to achieve the weight ratios shown in Table 1, with the total of the polypropylene resin and plant-derived linear low-density polyethylene being 100 wt%. After thorough mixing in the tumbler mixer, the mixture was divided into 25 kg portions and discharged to obtain a dry blend. The resulting dry blend was placed in a hopper equipped with an inner cone on a granulating extruder and extruded using a 45 mmφ twin-screw extruder (screw diameter 43 mmφ, L / D; 19.5) under conditions where the screw rotation speed and feeder rotation speed were adjusted to 200 rpm and 15 rpm, respectively, and the kneading zone temperature was adjusted to 250°C. The filter mesh configuration was 50 mesh / 100 mesh / 50 mesh. The mixture was granulated by a strand cut method, and the pellets were sized to a mesh size of 6.0 mm (upper limit) and 2.5 mm (lower limit), to obtain a masterbatch. The physical properties of the obtained masterbatch are shown in Table 1.

[0142] (Masterbatch: MB7) A masterbatch was obtained under the same conditions as MB1, except that the raw material ratios of MB7 shown in Table 1 were used, the screw rotation speed was 400 rpm, and the feeder rotation speed was 30 rpm, respectively, and the upper limit of the pellet mesh was φ9.0 mm. The physical properties of the obtained masterbatch are shown in Table 1.

[0143] (Example 1) (Raw materials used in the heat seal layer) PP-1: propylene-ethylene-butene random copolymer FL6745A (MFR 6.0 g / 10 min, melting point 130°C) manufactured by Sumitomo Chemical Silica: amorphous silica KMP130-4 (average particle size 4 μm) manufactured by Shin-Etsu Chemical Co., Ltd. Organic lubricant: behenic acid amide BNT-22H manufactured by Nippon Fine Chemicals Heat stabilizer: hindered phenol-based antioxidant Irganox 1010 manufactured by BASF Japan, phosphorus-based processing stabilizer Irgafos 168 manufactured by BASF Japan

[0144] (Raw materials used in the core layer) PP-2: propylene-ethylene-butene random copolymer FL8115A (MFR 7.0 g / 10 min, melting point 148°C) manufactured by Sumitomo Chemical LL-1: ethylene-hexene copolymer (plant-derived linear low-density polyethylene) SLH218 (MFR 2.3 g / min, density 916 kg / m) manufactured by Braskem ３ , melting point 126°C) Organic lubricant: Behenic acid amide BNT-22H manufactured by Nippon Fine Chemicals Heat stabilizer: Hindered phenol-based antioxidant Irganox 1010 manufactured by BASF Japan, phenol-based processing stabilizer Irgafos 168 manufactured by BASF Japan

[0145] (Raw materials used in the laminate layer) PP-2: propylene-ethylene-butene random copolymer FL8115A (MFR 7.0 g / 10 min, melting point 148°C) manufactured by Sumitomo Chemical Co., Ltd. LL-1: ethylene-hexene copolymer (plant-derived linear low-density polyethylene) SLH218 (MFR 2.3 g / 10 min, density 916 kg / m) manufactured by Braskem Co., Ltd. ３ , melting point 126°C) Heat stabilizer: hindered phenol-based antioxidant Irganox 1010 manufactured by BASF Japan, phenol-based processing stabilizer Irgafos 168 manufactured by BASF Japan

[0146] (Polyolefin Resin Film) For the polyolefin resin film of Example 1, raw materials were prepared based on the resin compositions and proportions of each layer shown in Table 2 below. The raw materials were transported in fixed amounts using a screw feeder, and each raw material was weighed. Each lightweight batch consisted of 14 kg for the laminate layer, 40 kg for the core layer, and 14 kg for the heat-seal layer. Furthermore, based on the weight of each layer listed in Table 1 as 100% by weight, 360 ppm of behenic acid amide was added to the seal layer as an organic lubricant, and 2000 ppm of silica with an average particle size of 4 μm was added as an inorganic anti-blocking agent in the form of a masterbatch. 270 ppm of behenic acid amide was added to the core layer as an organic lubricant in the form of a masterbatch.

[0147] (Melt extrusion) The mixed raw materials for the intermediate layer were extruded into a three-stage single-screw extruder with a screw diameter of 90 mm, and the mixed raw materials for the heat-seal layer and laminate layer were extruded into three-stage single-screw extruders with diameters of 65 mm and 45 mm, respectively, in the order of heat-seal layer / intermediate layer / laminate layer. The extruded materials were then extruded into a T-slot die with a width of 1400 mm, a two-stage preland, and a curved step portion designed to ensure uniform flow of the molten resin within the die, at an outlet temperature of 230° C. The thickness ratios of the heat-seal layer / core layer / laminate layer were 25% / 55% / 20%, respectively.

[0148] (Cooling) The molten resin sheet emerging from the die was cooled on a cooling roll at 35°C to obtain an unstretched polyolefin resin film with a thickness of 30 μm. During cooling on the cooling roll, both ends of the film on the cooling roll were fixed with air nozzles, and the entire width of the molten resin sheet was pressed against the cooling roll with an air knife. At the same time, a vacuum chamber was activated to prevent air entrapment between the molten resin sheet and the cooling roll. Both ends of the air nozzles were installed in series in the film traveling direction. The die was surrounded by a sheet to prevent wind from blowing onto the molten resin sheet. The suction port of the vacuum chamber was aligned with the traveling direction of the extruded sheet. (Trimming) The edge portions on both ends of the cooled and solidified polyolefin resin film were cut off with a slit blade and introduced to a separate line.

[0149] (Corona Treatment) The surface of the laminate layer of the film was subjected to corona treatment (power density 20 W min / m ２ ) was applied.

[0150] (Winding) The film-forming speed was 40 m / min. The edge portions of the formed film were trimmed. The film was wound up while applying tension and pressing with a contact roll to prevent wrinkles. After aging at 40°C for 24 hours, both ends were cut again using a slitting machine, and the film was wound into a roll with a width of 1000 mm, resulting in a film roll of 4004 m. A 2 m distance of film from the edge of the surface layer of the film roll was removed, and a further 2 m distance from the film was taken from the center in the width direction as a sample for measuring the physical properties of the film alone.

[0151] (Preparation of Laminate) The polyolefin resin films obtained in the Examples and Comparative Examples and a biaxially oriented polypropylene film (P2161, manufactured by Toyobo Co., Ltd., thickness 20 μm) as a base film were laminated with an ester adhesive obtained by mixing 33.6 parts by mass of a base agent (TM569, manufactured by Toyo-Morton Co., Ltd.), 4.0 parts by mass of a curing agent (CAT10L, manufactured by Toyo-Morton Co., Ltd.), and 62.4 parts by mass of ethyl acetate, at a coating amount of 3.0 g / m. ２ The resulting film was wound up and kept at 40° C. for 3 days to age it, thereby obtaining a laminate roll.

[0152] (Examples 2 to 8) In Example 1, the raw materials used for the core layer and laminate layer were changed to the ratios shown in Table 2, and a 30 μm polyolefin resin film was obtained in the same manner. A laminate was obtained in the same manner as in Example 1. Sumilizer GP, used as a heat stabilizer in Examples 2, 4, and 6, is a phenol-phosphorus antioxidant manufactured by Sumitomo Chemical. Table 3 shows the evaluation results.

[0153] (Comparative Examples 1, 2, 5, 6, 7, 8, and 9) In Example 1, the raw materials used for the heat seal layer, core layer, and laminate layer were changed to the ratios shown in Table 4, and a 30 μm polyolefin resin film was obtained in the same manner as in Example 1. A laminate was obtained in the same manner as in Example 1. Table 5 shows the evaluation results.

[0154] (Comparative Examples 3 and 4) In Example 1, the raw materials used for the core layer and laminate layer were changed to the ratios shown in Table 4, and in Comparative Example 3 the layer ratio of the heat seal layer was 20%, the layer ratio of the core layer was 60%, and in Comparative Example 4 the layer ratio of the heat seal layer was 3%, the layer ratio of the core layer was 94%, and the layer ratio of the laminate layer was 3%. A 30 μm polyolefin resin film was obtained in the same manner as in Example 1. A laminate was obtained in the same manner as in Example 1. Table 5 shows the evaluation results.

[0155] In Comparative Example 1, the plant-derived linear low-density polyethylene was added without using a masterbatch, and therefore the biomass content varied greatly in the flow direction.

[0156] In Comparative Example 2, the content of plant-derived linear low-density polyethylene in the core layer and the laminate layer was high, and therefore the heat seal strength was poor.

[0157] In Comparative Examples 3 and 4, the plant-derived linear low-density polyethylene was added without using a masterbatch, and therefore the biomass content varied greatly in the flow direction. In addition, the thickness of the heat seal layer was thin, and therefore the heat seal strength was poor.

[0158] In Comparative Example 5, the plant-derived linear low-density polyethylene was added without using a masterbatch, so the biomass content fluctuated greatly in the flow direction. Also, the addition of plant-derived linear low-density polyethylene to the heat seal layer resulted in poor heat seal strength.

[0159] In Comparative Example 6, the plant-derived linear low-density polyethylene was not added, and therefore the effect of reducing the environmental load was small.

[0160] In Comparative Example 7, the polyethylene ratio of the masterbatch was high and the angle of repose did not become small, so the biomass degree fluctuated greatly.

[0161] In Comparative Example 8, the shape of the masterbatch was large, and the variation in the biomass degree was large.

[0162] In Comparative Example 9, the MFR of the masterbatch was large, and the fluctuation in the biomass degree was large.

[0163]

[0164]

[0165]

[0166]

[0167]

[0168] The present invention can provide an environmentally friendly polyolefin resin film roll that has small variations in the biomass content in the product and a small number of defects, resulting in a low reject rate for packaging materials using the film and excellent heat seal strength, and can make a significant contribution to industry.

[0169] 1 Raw material hopper (slide gate type) 2 Raw material hopper (slide gate type) 3 Raw material hopper (slide gate type) 4 Raw material hopper (screw feeder type) 5 Mixing hopper 6 Weighing machine 7 Expansion blade 8 Transfer feeder 9 Standby hopper 10 Extruder 11 Inner cone

Claims

1. A roll made of a polyolefin-based resin film, the polyolefin-based resin film having at least one layer that satisfies the following a) and also satisfies the following b): a) The polyolefin-based layer contains a petroleum-derived propylene homopolymer and / or a propylene-α-olefin random copolymer, and a plant-derived linear low-density polyethylene, and the content of the petroleum-derived propylene homopolymer and / or the propylene-α-olefin random copolymer is 80% by weight or more and 95% by weight or less, and the content of the plant-derived linear low-density polyethylene is 5% by weight or more and 20% by weight or less, relative to the entire polyolefin-based resin constituting the layer. b) The standard deviation of the biomass degree in the longitudinal direction is 0.05% or more and 0.60% or less. The standard deviation is calculated by the following (Equation 1). [Equation 1]

2. The propylene homopolymer and / or propylene-α-olefin random copolymer has an MFR of 2.0 g / 10 min or more and 10.0 g / 10 min or less at 230°C and 2.16 kg, and the plant-derived linear low-density polyethylene has an MFR of 0.8 g / 10 min or more and 5.0 g / 10 min or less at 190°C and 2.16 kg, and a density of 912 kg / m ３ Above, 935kg / m ３ The polyolefin resin film roll according to claim 1, wherein the polyolefin resin film roll is:

3. 3. The polyolefin resin film roll according to claim 1, wherein the layer satisfying the requirement a) has an antioxidant content of 2000 ppm or more and 4000 ppm or less relative to the entire polyolefin resin composition constituting the layer.

4. 3. The polyolefin-based resin film roll according to claim 1, wherein the layer satisfying a) is present on at least one surface, and the ratio of the thickness of the layer satisfying a) to the thickness of the polyolefin-based resin film is 23% or more and 40% or less.

5. The polyolefin resin film roll according to claim 1 or 2, wherein the heat seal initiation temperature is 110°C or higher and 150°C or lower.

6. A laminate roll comprising a polyolefin-based resin film and a biaxially oriented film made of at least one polymer selected from the group consisting of a polyester-based resin film and a polypropylene-based resin film, wherein the polyolefin-based resin film has at least one layer that satisfies the following a) and also satisfies the following b). a) The polyolefin-based layer contains a petroleum-derived propylene homopolymer and / or a propylene-α-olefin random copolymer, and a plant-derived linear low-density polyethylene, and the content of the petroleum-derived propylene homopolymer and / or the propylene-α-olefin random copolymer is 80% by weight or more and 95% by weight or less, and the content of the plant-derived linear low-density polyethylene is 5% by weight or more and 20% by weight or less, relative to the entire polyolefin-based resin constituting the layer. b) The standard deviation of the biomass degree in the longitudinal direction is 0.05% or more and 0.60% or less. The standard deviation is calculated by the following (Equation 1). [Equation 2]

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