Laminating sealant film and laminated film

Abstract

To provide a polypropylene-based film and a lamination film capable of reducing environmental load without deteriorating the physical properties of a film by using biomass-derived polypropylene produced by the same production method as petroleum-derived polypropylene as a raw material for a film in a polypropylene-based film and a lamination film thereof used in the packaging field.SOLUTION: There is provided a polypropylene-based film in which a resin raw material comprises a biomass polypropylene including either or both of a propylene polymer obtained by polymerizing propylene produced by thermal cracking and fractionating bionaphtha or propylene produced by dehydrogenizing biopropane and a polypropylene copolymer obtained by poymerizing at least one of the propylene and an α-olefin, wherein the biomass polypropylene has a biomass degree of 5% or more, a melt flow rate of 0.1 to 50 g / 10 min and a density of 0.850 to 0.910 g / cm3.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a polypropylene film and a laminated film. [Background technology]

[0002] In recent years, the United Nations has set international goals for sustainable development known as the Sustainable Development Goals (SDGs), and there is a strong demand for initiatives to create a recycling-oriented society that reduces environmental impact by increasing the use of renewable resources. Renewable resources are primarily resources made from processed plants or plant-derived materials, and are also known as biomass resources. In the case of biomass resources, carbon dioxide from the atmosphere is absorbed as the plant grows. When used as a biomass resource for fuel, etc., it is decomposed again into water and carbon dioxide. Therefore, the amount of carbon dioxide does not increase. In other words, biomass resources are a resource that will need to be widely adopted in the future from the perspective of carbon neutrality.

[0003] In the field of plastics, biomass-derived plastics such as polylactic acid and biodegradable polymers are being produced, but production volumes are limited and they cannot be said to be widely used.On the other hand, with regard to polyethylene, the most commonly used material among general-purpose plastics, a method of obtaining polyethylene from plant-derived sugars via ethanol has been commercialized and is becoming widespread.

[0004] As a resin film using this biomass-derived polyethylene, a film using only an ethylene-based resin has been proposed (see, for example, Patent Documents 1 and 2). However, because this film is composed only of an ethylene-based resin, it has poor heat resistance. Also, a film has been proposed in which plant-derived polyethylene has been added to a polypropylene-based resin (see, for example, Patent Document 3). However, adding polyethylene to polypropylene reduces the transparency, heat resistance, and strength that are inherent to polypropylene film, and there is a trade-off between the desired physical properties of the film and the amount of biomass-derived polyethylene added, and there is a limit to the amount that can be added.

[0005] Furthermore, the biomass-derived polyethylene currently in widespread use is derived from sugarcane, and has a wider molecular weight distribution and a higher oligomer content than conventional petroleum-derived polyethylene, which poses problems such as reduced blocking resistance when made into a film. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-251006 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-046674 [Patent Document 3] Japanese Patent Application Publication No. 2018-065267 Summary of the Invention [Problem to be solved by the invention]

[0007] Therefore, the present invention has been proposed in view of the above circumstances, and by using biomass-derived polypropylene produced by the same manufacturing method as conventional petroleum-derived polypropylene as a raw material for polypropylene-based films and laminated films thereof, which are widely used in the packaging field, it is possible to reduce the environmental burden without deteriorating the physical properties of the film.Laminating sealant film and a laminated film. [Means for solving the problem]

[0008] That is, the first invention is a transparent sealant film for lamination, which is an unstretched polypropylene film made of a resin raw material mainly composed of polypropylene, and the resin raw material is a propylene polymer obtained by polymerizing propylene produced by thermal decomposition and fractional distillation of bionaphtha or propylene produced by dehydrogenation of biopropane. Body Contains biomass polypropylene and petroleum-based polypropylene. Contains The biomass content of the polypropylene film is 5% or more, The biomass polypropylene has a biomass content of 5% or more as measured by radiocarbon measurement, a melt flow rate (230°C, 2.16 kg load) of 0.1 to 50 g / 10 min, and a density of 0.850 to 0.910 g / cm 3 The present invention relates to a sealant film for lamination, characterized in that:

[0009] The second invention is a laminated film comprising a plurality of resin layers including the sealant film for lamination of the first invention. The biomass content of the entire laminated film is 5% or more. relates to. [Effects of the Invention]

[0011] The polypropylene film according to the first aspect of the present invention is a transparent sealant film for lamination, which is an unstretched polypropylene film made of a resin raw material mainly composed of polypropylene, and the resin raw material is a propylene polymer obtained by polymerizing propylene produced by thermal decomposition and fractional distillation of bionaphtha or propylene produced by dehydrogenation of biopropane. Body Contains biomass polypropylene and petroleum-based polypropylene. Contains The biomass content of the polypropylene film is 5% or more, The biomass polypropylene has a biomass content of 5% or more as measured by radiocarbon measurement, a melt flow rate (230°C, 2.16 kg load) of 0.1 to 50 g / 10 min, and a density of 0.850 to 0.910 g / cm 3Therefore, by using biomass-derived polypropylene produced by the same manufacturing method as conventional petroleum-derived polypropylene as a raw material for the film, it is possible to reduce the environmental impact without reducing the physical properties of the film, such as transparency, which are required for laminating sealant films. Furthermore, since the biomass content of the polypropylene film is 5% or more, it can contribute to reducing the environmental impact.

[0012] According to the second aspect of the present invention, a laminated film is made up of a plurality of resin layers including the sealant film for lamination of the first aspect of the present invention. A laminated film, wherein the biomass content of the entire laminated film is 5% or more. Therefore, by laminating films with properties suited to the application, it is possible to achieve performance comparable to that of conventional films while contributing to reducing environmental impact. Furthermore, since the biomass content of the entire laminated film is 5% or more, it can contribute further to reducing the environmental load. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic cross-sectional view of a biaxially oriented polypropylene film according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] The present invention relates to a polypropylene-based film, which is a single-layer film made of a resin material primarily composed of polypropylene and a single layer of the resin material, or a laminate film formed by laminating the polypropylene-based film with other films or resin layers to form multiple resin layers. When forming a laminate film, the resins constituting the polypropylene-based film can be co-extruded with the resins constituting each layer of the laminate film, or the films constituting each layer can be attached to form a laminate film with any layer configuration. For example, in the case of a three-layer structure as shown in FIG. 1, the first surface layer 11 and the second surface layer 12 can be polypropylene-based films, and the intermediate layer 13 can be composed of a polyethylene-based resin, with the resin configuration of the other layers being appropriate. The intermediate layer 13 may or may not contain a plant (biomass)-derived resin.

[0016] The resin raw material constituting the present invention includes biomass polypropylene made from so-called biomass raw materials derived from plants. Biomass polypropylene is obtained from bionaphtha, which is obtained by distillation separation of plant-derived oil, which is an oil made from plants, or biopropane, which is a by-product of biodiesel fuel obtained by decomposing plant-derived oil with a catalyst or the like. Examples of plant-derived oils include soybean oil, sesame oil, rice bran oil, sunflower oil, cottonseed oil, corn oil, rapeseed oil, olive oil, perilla oil, and almond oil, as well as waste oils from these oils, crude tall oil, a by-product of kraft pulp production, and oils extracted from wood such as wood chips.

[0017] The bionaphtha is then pyrolyzed and fractionated, and the resulting propylene is polymerized to produce biomass polypropylene. This propylene also includes propylene produced by a metathesis reaction of the ethylene and C4 fraction produced during the pyrolysis of the bionaphtha. When the bionaphtha is pyrolyzed, not only the propylene fraction but also the ethylene and C4 fraction can be used, resulting in improved yields. Alternatively, the propylene produced by dehydrogenating biopropane is polymerized to produce biomass polypropylene. The propylene used to produce biomass polypropylene can be produced not only from bionaphtha but also from a mixture of petroleum-derived naphtha as appropriate. The total amount of plant-derived oil, the raw material for bionaphtha, is smaller than fossil-derived oil, making it more difficult and expensive to secure than petroleum. Therefore, blending petroleum-derived naphtha ensures the total amount of (bio)naphtha and reduces production costs.

[0018] Furthermore, if the total amount of bio-naphtha is insufficient for an existing plant, it may be mixed with petroleum-derived naphtha for production. Similarly, when the raw material for bio-propylene is biopropane, it may be mixed with natural gas or petroleum-derived propane, and then processed through dehydrogenation and polymerization processes to produce bio-propylene.

[0019] Propylene produced by pyrolysis and fractionation of bionaphtha (and mixed naphtha) or by dehydrogenation of biopropane (and natural gas- or petroleum-derived propane) is polymerized with other propylene molecules to form propylene polymers. Examples of α-olefins include ethylene, 1-butene, 1-hexene, 1-octene, and 4-methyl-pentene-1. Examples of polypropylene copolymers polymerized with α-olefins include propylene-ethylene-butene copolymers, propylene-ethylene copolymers, and propylene-butene copolymers. The biomass polypropylene used in the present invention can be a mixture of either a propylene polymer or a polypropylene copolymer, or both, depending on the desired film properties. For example, a random copolymer is used to impart heat-sealing properties to the film, while a block copolymer is used to impart impact resistance and heat resistance for retort pouches.

[0020] Catalysts that can be used in producing the biomass polypropylene used in the present invention include magnesium-supported catalysts containing magnesium, halogen, titanium, and an electron donor as catalytic components, catalysts containing a solid catalyst component containing titanium trichloride as a catalyst and an organoaluminum, and metallocene catalysts. Specific catalyst production methods are not particularly limited, and an example is the Ziegler catalyst disclosed in JP 2007-254671 A.

[0021] The methods for distilling and separating bio-naphtha from plant-derived oils and for fractionating propylene from bio-naphtha are the same as conventional methods for producing propylene from petroleum. Therefore, propylene produced from plant-derived oils should have physical properties similar to those of petroleum-derived propylene. Therefore, using biomass polypropylene for part or all of the polypropylene used as a resin raw material for film is thought to reduce the environmental impact without compromising the physical properties of the film. For this reason, from the perspective of reducing the environmental impact, the biomass content of biomass polypropylene is specified as 5% or more.

[0022] The method of producing propylene by dehydrogenating biopropane obtained from plant-derived oil is the same as the method of producing propylene from natural gas or petroleum-derived propane. Therefore, propylene produced from plant-derived oil should have the same physical properties as propylene derived from natural gas or petroleum. Therefore, it is thought that using biomass polypropylene for part or all of the polypropylene used as a resin raw material for film can reduce the environmental impact. For this reason, from the perspective of reducing the environmental impact, the biomass content of biomass polypropylene is specified as 5% or more.

[0023] The biomass ratio can be determined by calculating the carbon content derived from plants (biomass) through radiocarbon (C14) measurement. For the biomass polypropylene of the present invention, values ​​measured through radiocarbon measurement were used. The measurement principle is as follows. Carbon in nature varies in weight, with three types: carbon-12 (C12), carbon-13 (C13), and carbon-14 (C14). Among these, carbon-14 exists in the atmosphere at a constant rate and has a characteristic of decreasing periodically, becoming half of its original amount in 5,730 years (half-life). Because plants absorb carbon dioxide from the atmosphere for growth, the carbon-14 content in plants is the same as that in the atmosphere. On the other hand, fossil resources such as petroleum do not contain carbon-14, so carbon-14 correlates with biomass ratio. Accelerator mass spectrometry (AMS) can measure the types of carbon contained in a sample and their respective proportions, allowing the biomass ratio of the sample to be calculated.

[0024] The biomass polypropylene used in the present invention has a melt flow rate (MFR) (230°C, 2.16 kg load) in the range of 0.1 to 50 g / 10 min. This allows the biomass polypropylene to be used in the same manner as conventional 100% petroleum-derived polypropylene, while suppressing deterioration in film performance and achieving the objective of the present invention of reducing environmental impact. The melt flow rate (MFR) is measured at 230°C in accordance with JIS K 7210 (2014). Generally, polypropylene with an MFR of 1 to 10 g / 10 min is suitable as the main raw material for film. However, adding raw materials outside this range can improve the formability of the film or provide the film with distinctive physical properties.

[0025] The density of the biomass polypropylene used in the present invention is also specified in the same manner, and is 0.850 to 0.910 g / cm 3 It is preferable that the density of biomass polypropylene is in the range of 0.890 to 0.910 g / cm. When biomass polypropylene is used in the same manner as conventional polypropylene, it is possible to suppress deterioration in film performance and reduce the environmental load. Generally, the density of biomass polypropylene is 0.890 to 0.910 g / cm as the main raw material for film. 3 However, by adding raw materials outside the range, the formability of the film can be improved or the film can have specific physical properties.

[0026] Furthermore, it is desirable that polypropylene films or laminated films containing biomass polypropylene have a biomass content of 5% or more. By achieving a biomass content of 5% or more, it is possible to effectively utilize biomass raw materials and reduce petroleum consumption, thereby further reducing the environmental impact. The biomass content of the film is derived from the results of radiocarbon concentration measurements.

[0027] The method for producing the film of the present invention is not particularly limited, and the film can be produced by a known method. For example, an unstretched film can be produced by extruding a molten resin to a predetermined thickness from a T-die, a circular die, or the like, and then cooling and solidifying the extruded molten resin using a cooling roll or air. Furthermore, a stretched film can be produced by uniaxially or biaxially stretching the extruded molten resin using a known tenter method, a tubular method, roll stretching, or the like.

[0028] The thickness of the film is determined appropriately depending on the application, and is preferably, for example, about 1 to 150 μm. A thickness of 10 to 60 μm is particularly suitable for packaging films. In the case of a laminated film 10, which is a three-layer co-extruded film as shown in FIG. 1, the layer ratio of surface layer 11:intermediate layer 13:surface layer 12 is preferably, for example, about 1:30:1 to 1:2:1.

[0029] The environmental impact can be further reduced by printing and laminating the film of the present invention using biomass ink or flexible packaging laminating adhesives made from renewable resources. It is also possible to laminate the film with different materials. Laminating the film with biomass polyethylene film, biomass polyamide film, biomass polyester film, etc., can further contribute to reducing the environmental impact.

[0030] In each layer of the film, various additives such as lubricants, antistatic agents, antiblocking agents, crystal nucleating agents, heat stabilizers, antioxidants, light stabilizers, ultraviolet absorbers, colorants, etc. It is also possible to use additives made from renewable resources.

[0031] For example, examples of lubricants that are mainly added to unstretched films include fatty acid amide compounds such as oleic acid amide, stearic acid amide, erucic acid amide, and behenic acid amide, and polyhydric alcohols such as glycerin monooleate, glycerin monostearate, glycerin distearate, diglycerin oleate, and diglycerin stearate. While examples of raw materials that can be used include animal fats and vegetable fats, the use of additives made from vegetable fats and oils such as soybean, palm, and coconut can further contribute to reducing the environmental load.

[0032] Antistatic agents that are mainly added to biaxially stretched films include aliphatic amine compounds such as lauryldiethanolamine, myristyldiethanolamine, oleyldiethanolamine, palmityldiethanolamine, and stearyldiethanolamine, and their ester compounds, i.e., aliphatic amine ester compounds, aliphatic amide compounds such as lauryldiethanolamide, myristyldiethanolamide, oleyldiethanolamide, and palmityldiethanolamide, and their ester compounds, i.e., aliphatic amide ester compounds, and polyhydric alcohols such as glycerin monooleate, glycerin monostearate, and glycerin distearate. Examples of raw materials used include animal fats and oils and vegetable fats, but the use of additives made from vegetable fats and oils such as soybean, palm, and coconut can further contribute to reducing the environmental impact.

[0033] Examples of the anti-blocking agent include granular materials such as silica particles, zeolite particles, cross-linked acrylic particles, cross-linked styrene particles, silicone particles, and talc particles.

[0034] Examples of the crystal nucleating agent include metal carboxylate crystal nucleating agents, sorbitol crystal nucleating agents, metal phosphate ester crystal nucleating agents, and β-crystal nucleating agents.

[0035] Additives can be added to each layer of the film as needed to improve strength, impart gas barrier properties, etc. Examples include calcium carbonate, talc, silica, clay, wollastonite, potassium titanate, xonotlite, gypsum fiber, aluminum borate, aramid fiber, carbon fiber, glass fiber, cellulose fiber, cellulose nanofiber, talc, mica, glass flakes, polyoxybenzoyl whiskers, synthetic mica, carbon black, carbon nanotubes, shirasu balloons, petroleum resins, and terpene resins. The use of additives made from renewable resources, such as cellulose and terpene resins, can further contribute to reducing the environmental impact.

[0036] As described above, biomass polypropylene produced by the same method as conventional petroleum-derived polypropylene should have similar physical properties to petroleum-derived polypropylene. If this is the case, then incorporating biomass polypropylene into a polypropylene-based film should not impair the properties or characteristics of the film. In other words, using the polypropylene-based film of the present invention as a substitute for a film made of 100% conventional petroleum-derived polypropylene can reduce the environmental impact.

[0037] For example, in anti-fog films used in packaging for fresh produce such as vegetables, biomass polypropylene may be included at a blending ratio of 10% in the polypropylene that makes up the middle layer of the film. The polypropylene in the middle layer of the anti-fog film is required to have high transparency so that the contents appear fresh. Because the physical properties of biomass polypropylene can be adjusted in the same way as petroleum-derived polypropylene, the inclusion of biomass polypropylene in the anti-fog film maintains the film's characteristics and physical properties, such as anti-fog properties and transparency, while also reducing the environmental impact.

[0038] In heat-seal films, biomass polypropylene may be included at a blending ratio of 10% in the heat-seal layer, which is the surface layer of the laminated film, or at a blending ratio of 5% in the middle layer. Heat-seal films made from biaxially oriented polypropylene films are primarily intended for standalone use, so high transparency is required. The polypropylene in the heat-seal layer must have high sealing strength. In the case of laminating sealant films, biomass polypropylene may be included at a blending ratio of 10% in the middle layer. By incorporating biomass polypropylene, which has properties equivalent to those of conventional petroleum-derived polypropylene, into heat-sealing films and laminating sealant films, it is possible to reduce the environmental impact while maintaining film properties such as heat-sealability.

[0039] In barrier films, biomass polypropylene may be incorporated at a blending ratio of 10% in the middle layer of a laminate film, or at a blending ratio of 50% in the first and second surface layers. When a barrier film is to be imparted with water vapor barrier properties, the polypropylene in the middle layer must have high crystallinity. Furthermore, when gas barrier properties are to be imparted, the film may be used as a coating substrate, so the middle or surface layer must have low low-molecular-weight substances and be heat-resistant. Even with biomass polypropylene, its physical properties can be adjusted, making it possible to reduce the environmental impact while maintaining the barrier properties of the barrier film.

[0040] In easy-peel films, it is conceivable that the middle layer will contain 30% biomass polypropylene, and the first surface layer will contain 50% biomass polypropylene, etc. Even when biomass polypropylene is included in the resin raw material, the heat seal strength can be controlled in the same way as when conventional polypropylene is used, so it is possible to ensure easy-peel properties while efficiently using renewable raw materials.

[0041] In the case of a substrate film for lamination, it is conceivable that the middle layer may contain 10% biomass polypropylene, or the first and second surface layers may contain 100% biomass polypropylene. As with the various films mentioned above, this will enable the creation of a film that is comparable to conventional films that use 100% petroleum-derived polypropylene, making it possible to contribute to reducing environmental impact without compromising the feel of use.

[0042] The polypropylene film of the present invention is not limited to the above-mentioned applications and methods of use, and can be used for a wide range of general applications, such as food packaging and industrial applications. For example, in the case of a biaxially oriented polypropylene film, it can be used as a surface substrate for lamination, a substrate for coating, a substrate for vapor deposition, an anti-fog film used for vegetable packaging, etc., a heat-seal film or a fusion-cut seal film that can be made into a bag by itself, a tape, a capacitor, etc. In the case of a non-oriented polypropylene film, it can be used as a general sealant film for lamination, a sealant film for special lamination with retort or easy-open properties, a packaging film for packaging bread, fresh noodles, etc. by itself, a substrate film for tapes, protective films, etc., a sealant film for secondary batteries, etc. [Example]

[0043] [Preparation of biaxially oriented polypropylene film] The biaxially oriented polypropylene films of prototypes 1 to 11 were prepared using the polypropylene resin and polyethylene resin described below. The biaxially oriented polypropylene films of prototypes 1 to 3 are expected to be used as general-purpose substrate films for lamination, the biaxially oriented polypropylene films of prototypes 4 to 6 as heat-sealing films used primarily alone, prototypes 7 to 9 as fusion-sealing films used primarily alone, and prototypes 10 and 11 as matte films for lamination.

[0044] The biaxially oriented polypropylene films of Examples 1 to 3 were prepared by kneading and melting the following materials, and then laminating them in the order of first surface layer, intermediate layer, and second surface layer. The materials were coextruded from a three-layer coextrusion T-die film molding machine set at 240°C, cooled on a 50°C cooling roll, and solidified to obtain a sheet-like material. The sheet-like material was then preheated at a set temperature of 100 to 120°C, stretched 5.0 times in the machine direction (MD), and annealed at a set temperature of 135°C. The sheet was preheated in a tenter at a set temperature of 180°C, stretched 8.0 times in the transverse direction (TD) at a set temperature of 160°C, and annealed at a set temperature of 165°C. After exiting the tenter, the first surface layer was subjected to corona discharge treatment and wound on a winder to obtain the biaxially oriented polypropylene films of Examples 1 to 3.

[0045] For Prototype Examples 4 to 6, the following materials were mixed and melted, and laminated in the order of first surface layer, intermediate layer, and second surface layer. The materials were coextruded from a three-layer coextrusion T-die film molding machine set at 240°C, cooled on a 50°C cooling roll, and solidified to obtain a sheet-like material. The sheet-like material was then preheated at a set temperature of 100-115°C, stretched 4.8 times in the machine direction (MD), and annealed at a set temperature of 135°C. It was preheated in a tenter at a set temperature of 180°C, stretched 8.0 times in the transverse direction (TD) at a set temperature of 155°C, and annealed at a set temperature of 160°C. After exiting the tenter, the first surface layer was subjected to a corona discharge treatment, and the film was wound up on a winder to obtain the biaxially oriented polypropylene films of Prototype Examples 4 to 6.

[0046] For Prototype Examples 7 to 9, the following materials were mixed and melted, and laminated in the order of first surface layer, intermediate layer, and second surface layer. The mixture was coextruded from a three-layer coextrusion T-die film molding machine set at 240°C, cooled on a 50°C cooling roll, and solidified to obtain a sheet-like material. The sheet-like material was then preheated at a set temperature of 100-110°C, stretched 4.8 times in the machine direction (MD), and annealed at a set temperature of 130°C. It was preheated in a tenter at a set temperature of 180°C, stretched 8.0 times in the transverse direction (TD) at a set temperature of 155°C, and annealed at a set temperature of 160°C. After exiting the tenter, the first and second surface layers were subjected to corona discharge treatment and wound on a winder to obtain the biaxially oriented polypropylene films of Prototype Examples 7 to 9.

[0047] For Prototype Examples 10 and 11, the following materials were mixed and melted, and laminated in the order of first surface layer, intermediate layer, and second surface layer. The mixture was coextruded from a three-layer coextrusion T-die film molding machine set at 240°C, cooled on a 50°C cooling roll, and solidified to obtain a sheet-like material. The sheet-like material was then preheated at a set temperature of 100-120°C, stretched 5.0 times in the machine direction (MD), and annealed at a set temperature of 135°C. It was preheated in a tenter at a set temperature of 180°C, stretched 8.0 times in the transverse direction (TD) at a set temperature of 160°C, and annealed at a set temperature of 165°C. After exiting the tenter, the second surface layer was subjected to corona discharge treatment and wound on a winder to obtain the biaxially oriented polypropylene films of Prototype Examples 10 and 11.

[0048] The thickness of the biaxially stretched polypropylene film was 30 μm for Samples 4 to 9, and 20 μm for the other samples.

[0049] [Materials used] Polypropylene resin (PP-1): Biomass polypropylene (Lyondell Basell, C14 HP456J), biomass content 46%, MFR (230°C / 2.16 kg) 3.4 g / 10 min, density 0.900 g / cm 3 , melting point 165℃ Polypropylene resin (PP-2): Petroleum-derived polypropylene (Japan Polypropylene Corporation, "FL203D"), biomass content 0%, MFR (230°C / 2.16 kg) 3.0 g / 10 min, density 0.900 g / cm 3 , melting point 164℃ Polypropylene resin (PP-3): Petroleum-derived polypropylene (Japan Polypropylene Corporation, "FW4BT"), biomass content 0%, MFR (230°C / 2.16 kg) 6.5 g / 10 min, density 0.900 g / cm 3 , melting point 135℃ Polypropylene resin (PP-4): Petroleum-derived polypropylene (Japan Polypropylene Corporation, "FX4G"), biomass content 0%, MFR (230°C / 2.16 kg) 5.0 g / 10 min, density 0.900 g / cm 3 , melting point 129℃ Polypropylene resin (PP-5): Petroleum-derived polypropylene (Japan Polypropylene Corporation, "BC4FC"), biomass content 0%, MFR (230°C / 2.16 kg) 8.0 g / 10 min, density 0.900 g / cm 3 , melting point 162℃ Polyethylene resin (PE-1): Biomass polyethylene (Braskem, SLH118), biomass content 92%, MFR (190°C / 2.16 kg) 1.0 g / 10 min, density 0.916 g / cm 3 , melting point 126℃ Polyethylene resin (PE-2): Petroleum-derived polyethylene (Ube Maruzen Polyethylene Co., Ltd., "R300"), biomass content 0%, MFR (190°C / 2.16 kg) 0.3 g / 10 min, density 0.921 g / cm 3 , melting point 109℃

[0050] Powdered synthetic silica ("Silisia 730" manufactured by Fuji Silysia Ltd.) was added as an antiblocking agent to the first and second surface layers, and an antistatic agent for polypropylene film was added to the middle layer.

[0051] The biomass content of the materials used was calculated by measuring radioactive carbon (C14) using an accelerator mass spectrometer (AMS). The melt flow rate (MFR) was measured in accordance with JIS K 7210 (2014) at 230°C for polypropylene resin and 190°C for polyethylene resin.

[0052] [Prototype 1] The first surface layer was made of 100% by weight of resin (PP-2), the middle layer was made of 24% by weight of resin (PP-1) and 76% by weight of resin (PP-2), and the second surface layer was made of 100% by weight of resin (PP-2), and the discharge rate of the raw materials was adjusted so that the ratio of first surface layer:middle layer:second surface layer was 1:18:1, thereby obtaining the biaxially oriented polypropylene film of Prototype Example 1. The biomass content of the biaxially oriented polypropylene film of Prototype Example 1 was 9.9%.

[0053] [Prototype 2] A biaxially oriented polypropylene film of Prototype Example 2 was obtained in the same manner as in Prototype Example 1, except that the intermediate layer was made of 100% by weight of resin (PP-2). The biomass content of the biaxially oriented polypropylene film of Prototype Example 2 was 0%.

[0054] [Prototype 3] The biaxially oriented polypropylene film of Prototype Example 3 was obtained in the same manner as in Prototype Example 1, except that the intermediate layer was made of 88% by weight of resin (PP-2) and 12% by weight of resin (PE-1). The biomass content of the biaxially oriented polypropylene film of Prototype Example 3 was 9.9%. The biomass content of Prototype Example 3 is derived from the polyethylene resin.

[0055] [Prototype 4] The first surface layer was made of 100% by weight of resin (PP-2), the middle layer was made of 30% by weight of resin (PP-1) and 70% by weight of resin (PP-2), and the second surface layer was made of 100% by weight of resin (PP-4), and the discharge rate of the raw materials was adjusted so that the ratio of first surface layer:middle layer:second surface layer was 1:28:1, thereby obtaining the biaxially oriented polypropylene film of Prototype Example 4. The biomass content of the biaxially oriented polypropylene film of Prototype Example 4 was 12.9%.

[0056] [Prototype 5] A biaxially oriented polypropylene film of Prototype Example 5 was obtained in the same manner as in Prototype Example 4, except that the intermediate layer was made of 100% by weight of resin (PP-2). The biomass content of the biaxially oriented polypropylene film of Prototype Example 5 was 0%.

[0057] [Prototype 6] The biaxially oriented polypropylene film of Prototype Example 6 was obtained in the same manner as in Prototype Example 4, except that the intermediate layer was made of 85% by weight of resin (PP-2) and 15% by weight of resin (PE-1). The biaxially oriented polypropylene film of Prototype Example 6 had a biomass content of 12.9%. The biomass content of Prototype Example 6 comes from the polyethylene resin.

[0058] [Prototype 7] The first surface layer was made of 100% by weight of resin (PP-4), the middle layer was made of 24% by weight of resin (PP-1) and 76% by weight of resin (PP-2), and the second surface layer was made of 100% by weight of resin (PP-4), and the discharge rate of the raw materials was adjusted so that the ratio of first surface layer:middle layer:second surface layer was 1:28:1, thereby obtaining the biaxially oriented polypropylene film of Prototype Example 7. The biomass content of the biaxially oriented polypropylene film of Prototype Example 7 was 10.3%.

[0059] [Prototype 8] A biaxially oriented polypropylene film of Prototype Example 8 was obtained in the same manner as in Prototype Example 7, except that the intermediate layer was made of 100% by weight of resin (PP-2). The biomass content of the biaxially oriented polypropylene film of Prototype Example 8 was 0%.

[0060] [Prototype 9] The biaxially oriented polypropylene film of Prototype Example 9 was obtained in the same manner as in Prototype Example 7, except that the intermediate layer was made of 88% by weight of resin (PP-2) and 12% by weight of resin (PE-1). The biaxially oriented polypropylene film of Prototype Example 9 had a biomass content of 10.3%. The biomass content of Prototype Example 9 comes from the polyethylene resin.

[0061] [Prototype 10] The first surface layer was made of 30% by weight of resin (PP-3), 35% by weight of resin (PP-5), and 35% by weight of resin (PE-2), the middle layer was made of 24% by weight of resin (PP-1) and 76% by weight of resin (PP-2), and the second surface layer was made of 100% by weight of resin (PP-4), and the discharge rate of the raw materials was adjusted so that the ratio of first surface layer:middle layer:second surface layer was 2:17:1, thereby obtaining the biaxially oriented polypropylene film of Prototype Example 10. The biomass content of the biaxially oriented polypropylene film of Prototype Example 10 was 9.4%.

[0062] [Prototype 11] A biaxially oriented polypropylene film of Prototype Example 11 was obtained in the same manner as in Prototype Example 10, except that the intermediate layer was made of 100% by weight of resin (PP-2). The biomass content of the biaxially oriented polypropylene film of Prototype Example 11 was 0%.

[0063] For prototypes 1 to 11, the haze (%), tensile strength at break (MPa), tensile elongation at break (%), and tensile modulus (GPa) were measured. For prototypes 1 to 9, the surface gloss (%) and narrow angle diffuse transmittance (LSI) (%) were also measured. Since prototypes 1 to 3 are substrate films for lamination, the water vapor permeability (g / m 2 The heat shrinkage rate (%) and the elongation time (days) were measured. For prototypes 4 to 6, the heat seal strength (N / 15 mm) was measured because they are heat-sealable films. For prototypes 7 to 9, the weld-cut seal strength (N / 15 mm) was measured because they are weld-cut sealable films. The resin ratio for each layer, the biomass content, and the measurement results for each prototype are shown in Tables 1 to 4.

[0064] [Haze measurement] Haze (%) is an index of transparency, and was measured in accordance with JIS K 7136 (2000) using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., "NDH-8000").

[0065] [Tensile properties] The tensile breaking strength (MPa), tensile breaking elongation (%), and tensile modulus (GPa) in the machine direction (MD) and transverse direction (TD) of the film were measured using a tensile testing machine (manufactured by Orientec Co., Ltd., "RTF-1310") in accordance with JIS K 7127 (1999).

[0066] [Heat shrinkage rate] The heat shrinkage of the film in the machine direction (MD) and the transverse direction (TD) at 120°C was measured in accordance with JIS Z 1712 (1999).

[0067] [Surface gloss measurement] The surface gloss (%) is an index showing the glossiness of the film surface, and was measured in accordance with JIS Z 8741 (1997) using a digital gloss meter (VG-7000, manufactured by Nippon Denshoku Kogyo Co., Ltd.).

[0068] [Measurement of narrow-angle diffuse transmittance] Narrow angle diffuse transmittance (LSI) (%) is an index of see-through ability, and indicates the ratio of the amount of scattered light at a scattering angle of 0.4° to 1.2° to the amount of total light transmitted. LSI is a measure of see-through ability to the naked eye, and the lower the value, the better the see-through ability. LSI was measured using a visual clarity tester (manufactured by Toyo Seiki Seisakusho Co., Ltd.).

[0069] [Water vapor permeability measurement] Water vapor permeability (g / m 2 ·day) was measured in accordance with JIS K 7129 (2008) using a water vapor transmission rate measuring device (manufactured by Mocon, "PERMATRAN-W (registered trademark) 3 / 33") under conditions of a temperature of 40°C and a relative humidity of 90%.

[0070] [Heat seal strength measurement] The heat seal strength (N / 15 mm) was measured as follows. The film was cut into rectangular test pieces (for heat sealing) measuring 50 mm in the transverse (TD) direction and 250 mm in the longitudinal (MD) direction. The sealant layers (second outer layers) of two test pieces were placed together and heat-sealed using a heat seal tester (Toyo Seiki Seisakusho Co., Ltd., "Thermal Gradient Tester") under conditions of a heat seal pressure of 0.4 MPa, a heat seal time of 1 second, and a set temperature of 160°C. A cellophane film was sandwiched between the heat sealer's hot plate and the test piece film to prevent adhesion. The center of the sealed portion of the heat-sealed test piece was cut into a 15 mm width, opened 180°, and measured using a small benchtop tester (Shimadzu Corporation, "EZ-SX"), with the unsealed portion clamped between zippers. The sealed portion was T-peeled at a tensile speed of 200 m / min. The maximum strength at a sealing temperature of 160°C was taken as the heat seal strength.

[0071] [Measurement of welding seal strength] The welding seal strength (N / 15 mm) was measured as follows: A bag was made by welding seal so that the second outer layer was on the inside of the bag. Sealing temperature: 400℃ Heating blade tip angle: 120°C Fusing interval: 200 mm Shot rate: 72 shots / minute

[0072] Then, 20 pieces were randomly selected from the resulting bags and subjected to measurement. Test pieces measuring 15 mm in width and 100 mm in length were cut out from one side of each bag, with the weld-sealed portions on each of the two sides positioned in the center, for a total of six test pieces. The test pieces were fixed in place with the chuck of a small tabletop testing machine (Shimadzu Corporation, "EZ-SX"), and the chuck distance of the test pieces was adjusted to 50 mm. The test pieces were stretched at 200 mm / min, and the strength at which the weld-sealed portions broke was measured. The average of the measured values ​​was taken as the weld-seal strength (N / 15 mm).

[0073] [Table 1]

[0074] [Table 2]

[0075] [Table 3]

[0076] [Table 4]

[0077] [Results and Discussion] Prototypes 1 to 3 are expected to be used as substrate films for lamination. Since they are often printed on the laminating surface, film transparency is required. In other words, films with lower values ​​for haze and narrow-angle diffuse transmittance (LSI), which are indicators of transparency, are considered to be superior. As shown in Tables 1 and 3, there was almost no difference in the physical properties between Prototype 1, which contains biomass polypropylene as a resin raw material and has a biomass content of 9.9%, and Prototype 2, which is made solely of petroleum-derived polypropylene. In other words, Prototype 1, which exhibited values ​​for haze and narrow-angle diffuse transmittance (LSI) equivalent to those of Prototype 2, a conventional petroleum-derived substrate film for lamination, was also shown to be a good substrate film for lamination. Therefore, films using biomass polypropylene as a resin raw material can be said to have functionality comparable to that of films made from conventional petroleum-derived polypropylene resins, and therefore can reduce environmental impact while maintaining the same usability as conventional films.

[0078] Although Prototype 3, which contains biomass polyethylene as a resin raw material, has the same biomass content as Prototype 1, its various physical properties are inferior. Its use as a replacement for conventional films does not provide the same user experience, making it unlikely to contribute to the promotion of biomass resource utilization. In particular, the narrow-angle diffuse transmittance (LSI) value is over 20%, making the film appear whitish and resulting in poor design when printed on the laminated surface. The film also has poor gloss, which is expected to result in poor appearance when used as packaging. Furthermore, its high water vapor permeability makes it unsuitable for packaging dry goods. Additionally, the film's low mechanical strength, particularly its low tensile modulus, may prevent it from meeting the rigidity requirements for packaging, potentially resulting in poor packaging suitability. The deterioration of the film's physical properties is likely due to the incomplete compatibility between polypropylene and polyethylene, resulting in the fine dispersion of polyethylene islands within a sea of ​​polypropylene. Furthermore, because the film is a mixture of different resins, it is inferior to Prototype 1 in terms of film recycling (monomaterial).

[0079] Prototypes 4 to 6 are expected to be used as stand-alone films for single-sided heat sealing. Prototypes 7 to 9 are expected to be used as stand-alone films for fusion-cut sealing. Both films require good transparency and rigidity. As shown in Tables 1 to 4, there was little difference in the physical properties between Prototype 4, which contains biomass polypropylene as a resin raw material and has a biomass content of 12.9%, and Prototype 5, which is made solely of petroleum-derived polypropylene. Similarly, there was little difference in the physical properties between Prototype 7, which has a biomass content of 10.3%, and Prototype 8, which is made solely of petroleum-derived polypropylene. The values ​​of haze and narrow-angle diffuse transmittance (LSI), which are indicators of transparency, were as low for Prototypes 4 and 7 as for Prototypes 5 and 8, respectively, and the tensile modulus, which is an indicator of rigidity, showed similar values. Therefore, films made from biomass polypropylene as a resin raw material can be said to have functionality that is in no way inferior to films made from conventional petroleum-derived polypropylene resins, and can therefore be said to be able to reduce environmental impact while maintaining the same usability as conventional films.

[0080] Although Prototypes 6 and 9, which contain biomass polyethylene as a resin raw material, have the same biomass content as Prototypes 4 and 7, respectively, their physical properties are inferior. They do not provide the same usability when used to replace conventional films, making them unlikely to contribute to promoting the use of biomass resources. In particular, Prototypes 6 and 9 exhibit narrow-angle diffuse transmittance (LSI) values ​​of 20% or more, resulting in a whitish film appearance and poor design when used alone. The poor glossiness also suggests a deterioration in the appearance of packaging. Additionally, the film's low mechanical strength, particularly its low tensile modulus, may prevent it from meeting the rigidity requirements for packaging and result in poor packaging suitability. The deterioration in the film's physical properties is likely due to the incomplete compatibility between polypropylene and polyethylene, resulting in the formation of finely dispersed polyethylene islands within a sea of ​​polypropylene. Furthermore, because the film is a mixture of different resins, it is understandable that it is inferior to Prototypes 4 and 7 from the perspective of film recycling (monomaterial).

[0081] Prototypes 10 and 11 are expected to be used as matte-finish laminating substrate films. Due to their unique texture, matte-finish biaxially oriented polypropylene films are often required for packaging applications such as expensive confectionery, where high design quality is often required, not only for appearance but also for a luxurious feel. As shown in Tables 2 and 4, there was almost no difference in the physical properties between Prototype 10, which contains biomass polypropylene as a resin raw material and has a biomass content of 9.4%, and Prototype 11, which is made solely of petroleum-derived polypropylene. Therefore, films made from biomass polypropylene as a resin raw material can be said to have functionality comparable to films made from conventional petroleum-derived polypropylene resins, and therefore can be said to reduce environmental impact while maintaining the same high quality texture and usability as conventional films.

[0082] [Production of unstretched film] Unstretched polypropylene films (Prototype Examples 12-18) and unstretched polyethylene films (Prototype Examples 19-22) were prepared using the polypropylene resin and polyethylene resin described below. Prototype Examples 19-22 are laminate films having a polypropylene film as one or two resin layers. The unstretched polypropylene films (Prototype Examples 12-15) are expected to be used as general-purpose laminating sealant films, and the unstretched polypropylene films (Prototype Examples 16-18) are expected to be used as easy-peel laminating sealant films. The unstretched polyethylene films (Prototype Examples 19 and 20) are expected to be used alone, such as by being heat-sealed. The unstretched polyethylene films (Prototype Examples 21 and 22) are expected to be used as matte surface substrates. Prototype Examples 19-22 are laminate films having a polypropylene film as a resin layer on the first or second surface layer. The following materials were melted and kneaded, co-extruded using a T-die film extruder, and cooled with a cooling roll to form a non-stretched film. The non-stretched films of each prototype were formed using the same settings.

[0083] [Materials used] Polypropylene resin (PP-1) Polypropylene resin (PP-3) Polypropylene resin (PP-4) Polypropylene resin (PP-5) Polypropylene resin (PP-6): Petroleum-derived polypropylene (Japan Polypropylene Corporation, "FB3B"), biomass content 0%, MFR (230°C / 2.16 kg) 7.5 g / 10 min, density 0.900 g / cm 3 , melting point 163℃ Polyethylene resin (PE-2) Polyethylene resin (PE-3): Biomass polyethylene (Braskem, SLH218), biomass content 92%, MFR (190°C / 2.16 kg) 2.3 g / 10 min, density 0.916 g / cm 3 , melting point 125℃ Polyethylene resin (PE-4): Petroleum-derived polyethylene (Prime Polymer Co., Ltd., "SP2040"), biomass content 0%, MFR (190°C / 2.16 kg) 3.8 g / 10 min, density 0.918 g / cm 3 , melting point 116℃ Polyethylene resin (PE-5): Petroleum-derived polyethylene (Ube Maruzen Polyethylene Co., Ltd., "F222NH"), biomass content 0%, MFR (190°C / 2.16 kg) 2.0 g / 10 min, density 0.922 g / cm 3 , melting point 110℃

[0084] Powdered synthetic silica ("Silisia 430" manufactured by Fuji Silysia Ltd.) was added as an anti-blocking agent to the first and second surface layers, and a slip agent for polypropylene film was added to the middle layer.

[0085] [Prototype 12] The first surface layer was made of 100% by weight of resin (PP-3), the middle layer was made of 75% by weight of resin (PP-3) and 25% by weight of resin (PP-6), and the second surface layer was made of 100% by weight of resin (PP-4).The extrusion rate of the raw materials was adjusted so that the ratio of first surface layer:middle layer:second surface layer was 1:4:1, and the film thickness was 30 μm, resulting in an unstretched polypropylene film of Prototype Example 12.The biomass content of the unstretched polypropylene film of Prototype Example 12 was 0%.

[0086] [Prototype 13] An unstretched polypropylene film of Prototype Example 13 was obtained in the same manner as in Prototype Example 12, except that the intermediate layer was made of 60% by weight of resin (PP-1) and 40% by weight of resin (PP-3). The biomass content of the unstretched polypropylene film of Prototype Example 13 was 18.4%.

[0087] [Prototype 14] An unstretched polypropylene film of Prototype Example 14 was obtained in the same manner as in Prototype Example 12, except that the first surface layer was made of 25% by weight of resin (PP-1) and 75% by weight of resin (PP-3). The biomass content of the unstretched polypropylene film of Prototype Example 14 was 1.9%.

[0088] [Prototype 15] An unstretched polypropylene film of Prototype Example 15 was obtained in the same manner as in Prototype Example 12, except that the first surface layer was made of 87.5% by weight of resin (PP-3) and 12.5% ​​by weight of resin (PE-3). The biomass content of the unstretched polypropylene film of Prototype Example 15 was 1.9%. The biomass content of Prototype Example 15 is derived from the polyethylene resin.

[0089] [Prototype 16] The first surface layer was made of 80% by weight of resin (PE-4) and 20% by weight of resin (PE-5), the middle layer was made of 100% by weight of resin (PP-6), the extrusion rate of the raw materials was adjusted so that the ratio of first surface layer:middle layer:second surface layer was 1:2:1, and the film thickness was set to 20 μm, but the same procedures as in Prototype Example 12 were followed to obtain the unstretched polypropylene film of Prototype Example 16. The biomass content of the unstretched polypropylene film of Prototype Example 16 was 0%.

[0090] [Prototype 17] An unstretched polypropylene-based film of Prototype Example 17 was obtained in the same manner as in Prototype Example 16, except that the first surface layer was made of 100% by weight of resin (PE-4) and the middle layer was made of 50% by weight of resin (PP-1) and 50% by weight of resin (PP-6). The biomass content of the unstretched polypropylene-based film of Prototype Example 17 was 11.5%.

[0091] [Prototype 18] An unstretched polypropylene film of Prototype Example 18 was obtained in the same manner as in Prototype Example 16, except that the intermediate layer was made of 50% by weight of resin (PP-1) and 50% by weight of resin (PP-3). The biomass content of the unstretched polypropylene film of Prototype Example 18 was 11.5%.

[0092] [Prototype 19] The unstretched polyethylene-based film of Prototype Example 19 was obtained in the same manner as in Prototype Example 12, except that the middle layer was made of 100% by weight of resin (PE-4) and the second surface layer was made of 100% by weight of resin (PP-3). The biomass content of the unstretched polyethylene-based film of Prototype Example 19 was 0%.

[0093] [Prototype 20] An unstretched polyethylene-based film of Prototype Example 20 was obtained in the same manner as in Prototype Example 19, except that the first surface layer and the second surface layer were made of 25% by weight of resin (PP-1) and 75% by weight of resin (PP-3). The biomass content of the unstretched polyethylene-based film of Prototype Example 20 was 3.8%.

[0094] [Prototype 21] An unstretched polyethylene-based film of Prototype Example 21 was obtained in the same manner as in Prototype Example 12, except that the first surface layer was made of 30 wt% resin (PP-3), 35 wt% resin (PP-5), and 35 wt% resin (PE-2), the middle layer was made of 100 wt% resin (PE-4), and the second surface layer was made of 100 wt% resin (PE-4). The biomass content of the unstretched polyethylene-based film of Prototype Example 21 was 0%.

[0095] [Prototype 22] An unstretched polyethylene-based film of Prototype Example 22 was obtained in the same manner as in Prototype Example 21, except that the first surface layer was made of 30% by weight of resin (PP-1), 35% by weight of resin (PP-5), and 35% by weight of resin (PE-2). The biomass content of the unstretched polyethylene-based film of Prototype Example 22 was 2.3%.

[0096] For Samples 12 to 22, the haze (%), tensile yield strength (MPa), tensile breaking strength (MPa), tensile breaking elongation (%), tensile modulus (GPa), and heat-seal initiation temperature (°C) were measured. Samples 12 to 15 were expected to be used as sealant films for lamination, so transparency was required. Therefore, the narrow-angle diffuse transmittance (LSI) (%) was measured. Samples 16 to 18 were expected to be used as easy-peel films for lamination, so their easy-peel suitability was evaluated. Samples 19 and 20 were intended for weld-sealing, so their weld-seal strength (N / 15 mm) was measured. The resin ratios for each layer, biomass content, and measurement results for each sample are shown in Tables 5 to 10. For Samples 19 to 22, the tensile yield strength (MPa) was not measured because polyethylene-based films do not have a yield point; this is indicated by "-" in the tables. Furthermore, since prototypes 21 and 22 are matte films expected to be used as surface substrates, the heat seal initiation temperature was not measured.

[0097] [Haze measurement] The haze (%) was measured in the same manner as in the biaxially oriented polypropylene film.

[0098] [Tensile properties] The tensile yield strength (MPa), tensile breaking strength (MPa), tensile breaking elongation (%), and tensile modulus (GPa) in the machine direction (MD) and transverse direction (TD) of the film were measured in accordance with JIS K 7127 (1999) using a tensile tester (manufactured by Orientec Co., Ltd., "RTF-1310"), in the same manner as in the measurements for the biaxially oriented polypropylene film described above.

[0099] [Measurement of heat seal initiation temperature] The heat-sealing initiation temperature (°C) is an index of processability and was measured in accordance with JIS Z 1713 (2009). The film was cut into rectangular test pieces (for heat sealing) measuring 50 mm x 250 mm (transverse (TD) direction x longitudinal (MD) direction of the film). The sealant layers (second outer layers) of two test pieces were placed together and heat-sealed using a heat-sealing tester (Toyo Seiki Seisakusho Co., Ltd., "Thermal Gradient Tester") at a heat-sealing pressure of 0.4 MPa and a heat-sealing time of 1 second. The test pieces were then heat-sealed using a 5°C temperature gradient tester. A cellophane film was sandwiched between the heat sealer's hot plate and the test piece film to prevent adhesion. The heat-sealed test piece was opened 180°, and the unsealed portion was clamped between the zippers of a small tabletop tester (Shimadzu Corporation, "EZ-SX"), and the sealed portion was T-peeled. The temperature at which the heat seal strength reached 3 (N / 15 mm) was then calculated by interpolation.

[0100] [Measurement of narrow-angle diffuse transmittance] The narrow angle diffuse transmittance (LSI) (%) was measured using a visual transparency tester (manufactured by Toyo Seiki Seisakusho, Ltd.) in the same manner as in the measurement of the biaxially stretched polypropylene film.

[0101] [Easy peel suitable] The easy-peel property was evaluated as an index of the ease of opening when used as a lid for a bag or container by the following method. The surface of the first surface layer of each of the prototypes 16 to 18 was subjected to a corona discharge treatment, a polyester-based dry laminating adhesive was applied, and a 15 μm biaxially oriented nylon film was attached to form a laminated film. The laminated film was then cut into rectangular test pieces (for heat sealing) measuring 50 mm × 250 mm (transverse (TD) direction × longitudinal (MD) direction of the film). The second surface layers (heat seal layers) of the cut test pieces were placed together and heat-sealed using a heat-sealing tester (Toyo Seiki Seisakusho Co., Ltd., "Thermal Gradient Tester") under conditions of a heat-sealing pressure of 0.4 MPa, a heat-sealing time of 1 second, and a set temperature of 150°C. The center of the heat-sealed test piece was cut to a width of 15 mm, opened 180°, and the unsealed portion was clamped in a small tabletop testing machine (Shimadzu Corporation, "EZ-SX"), and the sealed portion was T-peeled at a tensile speed of 200 m / min to measure the seal strength. Furthermore, the peeled surface of the measured sample was observed to confirm that peeling was progressing within the film of the prototype. Films with a seal strength of 1 to 15 N / 15 mm and in which peeling was progressing within the film were rated "Good," while others were rated "Poor." Films rated "Poor" were prone to tearing or were difficult to open, and therefore did not possess easy-peel suitability.

[0102] [Measurement of welding seal strength] The welding seal strength (N / 15 mm) was measured in the same manner as in the measurement for the biaxially oriented polypropylene film, except that the welding seal condition was changed to 350°C.

[0103] [Table 5]

[0104] [Table 6]

[0105] [Table 7]

[0106] [Table 8]

[0107] [Table 9]

[0108] [Table 10]

[0109] [Results and Discussion] Prototypes 12 to 15 are expected to be used as laminating sealant films. As shown in Tables 5 and 8, there was little difference in the physical properties between Prototype 13, which contains biomass polypropylene as a resin raw material and has a biomass content of 18.4%, Prototype 14, which has a biomass content of 1.9%, and Prototype 12, which is made solely of petroleum-derived polypropylene. In particular, since printing on the laminated surface is expected, film transparency is required. That is, films with lower values ​​of haze and narrow-angle diffuse transmittance (LSI), which are indicators of transparency, can be said to be superior. As shown in Table 8, Prototypes 13 and 14 showed values ​​similar to those of Prototype 12, indicating that both are excellent as laminating sealant films. In other words, regardless of which layer biomass polypropylene is used as a resin raw material, the film properties do not change significantly from those when petroleum-derived polypropylene is used, and usability, feel, and handling remain unchanged. This demonstrates its potential as a replacement for conventional petroleum-derived films.

[0110] In prototype 15, which contained biomass polyethylene in the first surface layer, the narrow-angle diffuse transmittance (LSI) was higher and transparency was poorer than in prototype 14, which had the same raw material composition for the intermediate layer. The reason for this deterioration in physical properties is thought to be that polypropylene and polyethylene are not completely compatible, resulting in finely dispersed polyethylene islands in a sea of ​​polypropylene. Furthermore, the incorporation of sugarcane-derived biomass polyethylene as a resin raw material tends to result in poor film properties, and it is thought that there is a limit to the amount that can be added to achieve the desired physical properties. In contrast, biomass polypropylene does not show any deterioration in film properties due to the amount added, so there is no limit to the amount that can be added, and it is thought that it will make a significant contribution to reducing environmental impact.

[0111] Prototypes 16 to 18 are expected to be used as easy-peel films for lamination. As shown in Tables 6 and 9, Prototypes 17 and 18 exhibited easy-peel properties comparable to those of Prototype 16, even when 50% of the middle layer was replaced with biomass polypropylene. In other words, whether biomass polypropylene was used as the resin raw material and incorporated into any layer, the film properties did not change significantly compared to when petroleum-derived polypropylene was used, and the ease of use, feel, handling, etc. remained unchanged. This demonstrated its potential as a replacement for conventional petroleum-derived films.

[0112] Prototypes 19 and 20 are expected to be used as stand-alone weld-seal films. The inclusion of a polyethylene layer in the middle layer allows for the packaging of heavy items. As shown in Tables 7 and 10, Prototype 20 exhibited weld-seal strength comparable to that of Prototype 19, even when 25% of the first and second outer layers were replaced with biomass polypropylene. In other words, whether biomass polypropylene is used as the resin raw material and incorporated into any layer, the film's properties are not significantly different from those when petroleum-derived polypropylene is used, and the ease of use, feel, and handling remain unchanged. This demonstrates its potential as a replacement for conventional petroleum-derived films.

[0113] Prototypes 21 and 22 are expected to be used as matte films for surface substrates. As shown in Tables 7 and 10, Prototype 22 exhibited a matte appearance comparable to that of Prototype 21, even when 30% of the first surface layer was replaced with biomass polypropylene. In other words, whether biomass polypropylene was used as the resin raw material and incorporated into any layer, the film properties did not change significantly compared to when petroleum-derived polypropylene was used, and the ease of use, feel, handling, etc. remained unchanged. This demonstrated its potential as a replacement for conventional petroleum-derived films. [Industrial Applicability]

[0114] The polypropylene-based film and laminated film of the present invention are made from a resin raw material containing biomass polypropylene produced from bio-naphtha obtained from plant-derived oil or propylene made from bio-propane, and therefore are promising as alternatives to conventional films because they can reduce the environmental load while suppressing deterioration in film performance. [Explanation of symbols]

[0115] 10 Laminated film 11 First surface layer 12 Second surface layer 13 Middle class

Claims

1. A transparent sealant film for lamination, which is an unstretched polypropylene film made of a resin material mainly composed of polypropylene, The resin raw material contains biomass polypropylene containing a propylene polymer obtained by polymerizing propylene produced by thermal decomposition and fractional distillation of bionaphtha or propylene produced by dehydrogenation of biopropane, and petroleum-derived polypropylene, The biomass content of the polypropylene film is 5% or more, The biomass content of the biomass polypropylene as measured by radiocarbon measurement is 5% or more, and a melt flow rate (230°C, 2.16 kg load) of 0.1 to 50 g / 10 min; Density is 0.850 to 0.910 g / cm ３ is A sealant film for lamination characterized by the above.

2. A laminated film comprising a plurality of resin layers including the sealant film for lamination according to claim 1, wherein the biomass content of the entire laminated film is 5% or more.

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