Transparent 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 in a polypropylene-based film and a lamination film used extensively in the packaging field.SOLUTION: There is provided a polypropylene-based film made of a resin raw material mainly comprising a polypropylene, wherein the 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] This invention transparent Regarding films and laminated films. [Background technology]

[0002] In recent years, the United Nations has established international goals for sustainable development known as the Sustainable Development Goals (SDGs), and there is a growing demand for efforts toward a circular economy that reduces environmental impact by increasing the utilization of renewable resources. Renewable resources are mainly plants and resources processed from plant-derived materials, and are also called biomass resources. In the case of biomass resources, carbon dioxide from the atmosphere is absorbed as the plant grows. Then, when used as fuel or other biomass resources, they are broken down again into water and carbon dioxide. Therefore, the amount of carbon dioxide does not increase. In other words, biomass resources are resources that need to be incorporated into large quantities in the future from the standpoint of carbon neutrality.

[0003] In the field of plastics, while biomass-derived plastics such as polylactic acid and biodegradable polymers are being manufactured, their production volume is limited, and they cannot be widely used. On the other hand, regarding polyethylene, the most widely 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 biomass-derived polyethylene, a film using only ethylene-based resin has been proposed (see, for example, Patent Documents 1 and 2). However, because this film is composed only of ethylene-based resin, it has poor heat resistance. In addition, a film in which plant-derived polyethylene is added to polypropylene resin has been proposed (see, for example, Patent Document 3). However, adding polyethylene to polypropylene reduces the transparency, heat resistance, and strength inherent in polypropylene film, and there is a trade-off relationship between the desired film properties and the amount of biomass-derived polyethylene added, so there are limitations on the amount that can be added.

[0005] Furthermore, the biomass-derived polyethylene currently in widespread use is derived from sugarcane, and compared to conventional petroleum-derived polyethylene, it has a wider molecular weight distribution and contains more oligomers, which leads to problems such as reduced blocking resistance when used in film form. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2012-251006 [Patent Document 2] Japanese Patent Publication No. 2014-046674 [Patent Document 3] Japanese Patent Publication No. 2018-065267 [Overview of the project] [Problems that the invention aims to solve]

[0007] Therefore, the present invention has been proposed in view of the above circumstances, and in polypropylene films and laminated films thereof, which are widely used in the packaging field, 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 burden without degrading the physical properties of the film. transparent We provide films and laminated films. [Means for solving the problem]

[0008] In other words, the first invention is a polypropylene-based film made from a resin raw material mainly composed of polypropylene. A transparent film for single-sided heat sealing or heat-sealing. The resin raw material is a polymer of propylene produced by the thermal decomposition and fractional distillation of bionaphtha or propylene produced by the dehydrogenation of biopropane. Including the body Biomass polypropylene And, petroleum-derived polypropylene and It contains, The biomass content of the aforementioned polypropylene film is 5% or more. The biomass content of the aforementioned biomass polypropylene, as measured by radiocarbon dating, is 5% or more, and the melt flow rate (230°C, 2.16 kg load) is 0.1 to 50 g / 10 min, with a density of 0.850 to 0.910 g / cm³. 3 It is characterized by being transparent Related to film.

[0009] The second invention is a modification of the first invention. transparent This relates to a laminated film consisting of multiple resin layers, including a film. [Effects of the Invention]

[0011] Regarding the first invention transparent According to the film, it is a polypropylene-based film made from resin raw materials, mainly polypropylene. A transparent film for single-sided heat sealing or heat-sealing. The resin raw material is a polymer of propylene produced by the thermal decomposition and fractional distillation of bionaphtha or propylene produced by the dehydrogenation of biopropane. Including the body Biomass polypropylene And, petroleum-derived polypropylene and It contains, The biomass content of the aforementioned polypropylene film is 5% or more. The biomass content of the aforementioned biomass polypropylene, as measured by radiocarbon dating, is 5% or more, and the melt flow rate (230°C, 2.16 kg load) is 0.1 to 50 g / 10 min, with a density of 0.850 to 0.910 g / cm³. 3Therefore, by using biomass-derived polypropylene produced by the same manufacturing method as conventional petroleum-derived polypropylene as the raw material of the film, it is possible to reduce the environmental load without degrading the physical properties of the film.

[0012] According to the laminated film according to the second invention, transparent Since it is composed of a plurality of resin layers including the film of the first invention, by laminating a film having physical properties according to the application, it is possible to contribute to reducing the environmental load while having performance comparable to that of conventional films.

Brief Description of the Drawings

[0014] [Figure 1] It is a schematic cross-sectional view of a biaxially stretched polypropylene film according to an embodiment of the present invention.

Mode for Carrying Out the Invention

[0015] The present invention is a polypropylene-based film made of a resin raw material mainly composed of polypropylene and being a single-layer film composed of a single layer of the resin raw material, or a laminated film formed by laminating the polypropylene-based film with other films or resin layers to form a plurality of resin layers. When it is a laminated film, it can be formed by co-extruding the resin constituting the polypropylene-based film together with the resins constituting each layer of the laminated film, or by adhering the films constituting each layer, so as to have an arbitrary layer structure. Here, 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 may be made of a polypropylene-based film, and the intermediate layer 13 may be made of a polyethylene-based resin, and the resin compositions of other layers are appropriate. The intermediate layer 13 may or may not contain a resin derived from plants (biomass).

[0016] The resin raw materials constituting the present invention include 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 oils, or from biopropane, a by-product of biodiesel fuel obtained by decomposing plant-derived oils with a catalyst or the like. Examples of plant-derived oils include soybean oil, sesame oil, rice oil, sunflower oil, cottonseed oil, corn oil, rapeseed oil, olive oil, perilla oil, almond oil, as well as their waste oils, crude tall oil, a by-product of kraft pulp production, and oils extracted from wood such as wood chips.

[0017] Then, the propylene produced by the thermal decomposition and fractional distillation of bionaphtha is polymerized to produce biomass polypropylene. This propylene also includes propylene produced by the metathesis reaction of ethylene and C4 fractions generated during the thermal decomposition of bionaphtha. Since not only the propylene fraction but also the ethylene and C4 fractions can be used when bionaphtha is thermally decomposed, the yield is improved. Alternatively, propylene produced by dehydrogenating biopropane is polymerized to produce biomass polypropylene. Here, the propylene that forms the basis of biomass polypropylene is not only from bionaphtha, but may also be produced by mixing it with petroleum-derived naphtha as appropriate. This is because the total amount of plant-derived oil, which is the raw material for bionaphtha, is less than that of fossil-derived oil, making it more difficult to secure or more expensive than petroleum. By mixing it with petroleum-derived naphtha, the total amount of (bio)naphtha can be secured and manufacturing costs reduced.

[0018] Furthermore, if the total amount of bionaphtha is insufficient for existing plants, it may be mixed with petroleum-derived naphtha during production. Similarly, if the raw material for biomass polypropylene is biopropane, it is conceivable that natural gas or petroleum-derived propane may be mixed in, and then dehydrogenated and polymerized to produce biomass polypropylene.

[0019] Propylene produced by dehydrogenating propylene or biopropane (and natural gas or petroleum-derived propane) generated by the thermal decomposition and fractional distillation of bionaphtha (and mixed naphtha) can be polymerized with other propylenes to form a propylene polymer. Examples of α-olefins include ethylene, 1-butene, 1-hexene, 1-octene, and 4-methylpentene-1. Examples of polypropylene copolymers polymerized with α-olefins include propylene-ethylene-butene copolymer, propylene-ethylene copolymer, and propylene-butene copolymer. The biomass polypropylene used in this invention can be appropriately blended with either propylene polymer or polypropylene copolymer, or both, depending on the desired properties of the film. For example, when imparting heat-sealing properties to the film, a random copolymer is used, while when imparting impact resistance and heat resistance for retort pouches, a block copolymer is used.

[0020] Examples of catalysts used in producing biomass polypropylene for use in the present invention include magnesium-supported catalysts with magnesium, halogens, titanium, and electron donors as catalytic components, catalysts consisting of a solid catalyst component with titanium trichloride as a catalyst and organoaluminum, and metallocene catalysts. The specific method for producing the catalyst is not particularly limited, and as an example, the Ziegler catalyst disclosed in Japanese Patent Application Publication No. 2007-254671 is provided.

[0021] The method of distilling and separating bionaphtha from plant-derived oil and the method of fractionally distilling propylene from bionaphtha are the same as the conventional method of producing propylene from petroleum. Therefore, propylene produced from plant-derived oil should have the same physical properties as petroleum-derived propylene. Thus, by using biomass polypropylene for part or all of the polypropylene used as a resin raw material for films, it is possible to reduce the environmental burden without impairing the physical properties of the film. For this reason, from the perspective of reducing environmental burden, the biomass content of biomass polypropylene is stipulated to be 5% or more.

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

[0023] The biomass content can be determined by calculating the carbon content derived from plants (biomass) using radiocarbon (C14) measurement. In the biomass polypropylene of this invention, the value measured by radiocarbon measurement was used. The measurement principle is as follows: Carbon in nature exists in three forms with different weights: carbon-12 (C12), carbon-13 (C13), and carbon-14 (C14). Among these, carbon-14 is always present in the atmosphere at a constant rate and decreases at a fixed cycle, becoming half of its original amount in 5730 years (half-life). Plants absorb carbon dioxide from the atmosphere for growth, so the proportion of carbon-14 contained 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 the biomass content. An accelerator mass spectrometer (AMS) can measure the types of carbon contained in a sample and their respective proportions, and therefore can calculate the biomass content of the sample.

[0024] The biomass polypropylene used in this invention has a melt flow rate (MFR) (230°C, 2.16 kg load) within the range of 0.1 to 50 g / 10 min. This allows for reduced environmental impact while suppressing film performance degradation, even when used in the same way as conventional 100% petroleum-derived polypropylene. 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 film moldability or impart characteristic physical properties to the film.

[0025] Similarly, the density of the biomass polypropylene used in this invention is also defined as 0.850 to 0.910 g / cm³. 3 It is preferable that the density be within this range. If biomass polypropylene has a density within this range, even when used in the same way as conventional polypropylene, it is possible to reduce the environmental impact while suppressing the deterioration of film performance. Generally, the main raw material for film has a density of 0.890 to 0.910 g / cm³. 3 Polypropylene is suitable. However, adding raw materials outside this range can improve the moldability of the film or give it characteristic 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 use, 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 manufacturing the film of the present invention is not particularly limited and can be manufactured by known methods. For example, an unstretched film is manufactured by extruding molten resin from a T-die or circular die to a predetermined thickness, and then cooling and solidifying it using a cooling roll or air. Furthermore, a stretched film is manufactured by uniaxial or biaxial stretching using known methods such as the tenter method, tubular method, or roll stretching.

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

[0029] If the film of the present invention is printed and laminated using biomass inks or flexible packaging laminating adhesives made from renewable resources, the environmental impact can be further reduced. Lamination with different materials is also conceivable. 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, nucleating agents, heat stabilizers, antioxidants, light stabilizers, ultraviolet absorbers, and colorants may be added as needed. It is also conceivable to use additives made from renewable resources.

[0031] For example, lubricants mainly added to unstretched films include fatty acid amide compounds such as oleamide, stearamide, erucamide, and behenamide, and polyhydric alcohols such as glycerin monooleate, glycerin monostearate, glycerin distearate, diglycerin oleate, and diglycerin stearate. While animal fats and vegetable oils are used as raw materials, the use of additives derived from vegetable oils such as soybean, palm, and coconut can further contribute to reducing environmental impact.

[0032] Antistatic agents mainly added to biaxially oriented films include aliphatic amine compounds such as lauryl diethanolamine, myristyl diethanolamine, oleyl diethanolamine, palmityl diethanolamine, and stearyl diethanolamine, as well as aliphatic amine ester compounds, aliphatic amide compounds such as lauryl diethanolamide, myristyl diethanolamide, oleyl diethanolamide, and palmityl diethanolamide, as well as aliphatic amide ester compounds, and polyhydric alcohols such as glycerin monooleate, glycerin monostearate, and glycerin distearate. While animal fats and vegetable oils are used as raw materials, using additives made from vegetable oils such as soybean, palm, and coconut can further contribute to reducing environmental impact.

[0033] Examples of antiblocking agents 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 crystal nucleating agents include carboxylate metal salt-based crystal nucleating agents, sorbitol-based crystal nucleating agents, phosphate ester metal salt-based crystal nucleating agents, and β-crystal nucleating agents.

[0035] In each layer of the film, additives can be added 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 resin, terpene resin, etc. By using additives made from renewable resources such as cellulose and terpene resin, it is possible to further reduce the environmental burden.

[0036] As mentioned above, biomass polypropylene produced by the same method as conventional petroleum-derived polypropylene should have the same physical properties as petroleum-derived polypropylene. If so, then incorporating biomass polypropylene into a polypropylene-based film should not impair the film's properties or characteristics. In other words, the present invention serves as a substitute for films made of 100% conventional petroleum-derived polypropylene. of By using film, it becomes possible to reduce the environmental impact.

[0037] For example, in anti-fog films used as packaging materials for fresh produce such as vegetables, it is conceivable that biomass polypropylene may be included at a ratio of 10% in the polypropylene that constitutes the intermediate layer. The polypropylene in the intermediate layer of an anti-fog film requires high transparency so that the contents appear fresh. Since the physical properties of biomass polypropylene can be adjusted in the same way as petroleum-derived polypropylene, even if biomass polypropylene is included in an anti-fog film, the film's properties such as anti-fog properties and transparency can be maintained, while reducing the environmental impact.

[0038] In heat-seal films, it is conceivable that biomass polypropylene may be included at a 10% ratio in the heat-seal layer on the surface of the laminated film, or at a 5% ratio in the intermediate layer. Furthermore, since heat-seal films made of biaxially oriented polypropylene are mainly intended for standalone use, high transparency is required. High sealing strength is required for the polypropylene in the heat-seal layer. In the case of laminate sealant films, it is conceivable that biomass polypropylene may be included at a 10% ratio in the intermediate layer. Even in heat-seal films and laminate sealant films, by including biomass polypropylene that has physical properties equivalent to conventional petroleum-derived polypropylene, it is possible to reduce the environmental impact while ensuring film properties such as heat sealability.

[0039] In barrier films, it is conceivable that biomass polypropylene may be included at a 10% blending ratio in the intermediate layer of the laminated film, or at a 50% blending ratio in the first and second surface layers. When water vapor barrier properties are to be imparted to the film in a barrier film, high crystallinity is required for the polypropylene in the intermediate layer. Furthermore, when gas barrier properties are to be imparted, the film may be used as a coating substrate, so the intermediate or surface layer must have a low amount of low molecular weight materials and high heat resistance. Even with biomass polypropylene, the properties can be adjusted, so it is 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 intermediate layer contains 30% biomass polypropylene, or that the first surface layer contains 50% biomass polypropylene. 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, thus enabling the efficient use of renewable raw materials while ensuring easy-peel properties.

[0041] In laminate base films, it is conceivable that biomass polypropylene may be included in the intermediate layer at a 10% blending ratio, or that the first and second surface layers may contain biomass polypropylene at a 100% blending ratio. Similar to the various films mentioned above, it is possible to create films that are comparable to conventional films using 100% petroleum-derived polypropylene, thus contributing to the reduction of environmental impact without compromising usability.

[0042] This invention of The film is not limited to the uses and methods described above, but can be used for a wide range of general applications, such as food packaging and industrial applications. For example, biaxially oriented polypropylene films can be used as a surface substrate for lamination, a substrate for coating, a substrate for vapor deposition, an anti-fogging film used for vegetable packaging, a heat-sealable film or heat-sealable film that can be made into bags using the film alone, as well as tapes and capacitors. Unoriented polypropylene films can be used as general laminating sealant films, special laminating sealant films with retort and easy-open properties, as well as packaging films for wrapping bread and fresh noodles using the film alone, base films for tapes and protective films, and sealant films for secondary batteries. [Examples]

[0043] [Fabrication of biaxially oriented polypropylene films] Biaxially oriented polypropylene films, prototypes 1 to 11, were created using the polypropylene resin and polyethylene resin described later. The biaxially oriented polypropylene films of prototypes 1 to 3 are intended to be used as general-purpose base films for lamination, the biaxially oriented polypropylene films of prototypes 4 to 6 are intended to be used primarily as heat-seal films on their own, prototypes 7 to 9 are intended to be used primarily as heat-seal films on their own, and prototypes 10 and 11 are intended to be used as matte-finish films for lamination.

[0044] The biaxially oriented polypropylene films of prototypes 1-3 were prepared by kneading and melting the following materials, setting them to be laminated in the order of first surface layer, intermediate layer, and second surface layer, and co-extruding them from a three-layer co-extrusion T-die film molding machine set to 240°C. The resulting sheets were then cooled and solidified on a cooling roll at 50°C to obtain the raw material. Next, the sheets were preheated to a set temperature of 100-120°C, stretched 5.0 times in the longitudinal (MD) direction, and then annealed at a set temperature of 135°C. In the tenter, the sheets were preheated to a set temperature of 180°C, stretched 8.0 times in the transverse (TD) direction at a set temperature of 160°C, and then annealed at a set temperature of 165°C. After exiting the tenter, the first surface layer was subjected to corona discharge treatment, and the sheets were wound up on a winding machine to obtain the biaxially oriented polypropylene films of prototypes 1-3.

[0045] For prototypes 4-6, the following materials were kneaded and melted, and the layers were set to be laminated in the order of first surface layer, intermediate layer, and second surface layer. The mixture was co-extruded from a three-layer co-extrusion T-die film molding machine set to 240°C, cooled and solidified on a cooling roll at 50°C to obtain a sheet-like material that would become the raw material. Next, the sheet-like material was preheated to a set temperature of 100-115°C, stretched 4.8 times in the longitudinal (MD) direction, and then annealed at a set temperature of 135°C. In a tenter, it was preheated to a set temperature of 180°C, stretched 8.0 times in the transverse (TD) direction at a set temperature of 155°C, and then annealed at a set temperature of 160°C. After exiting the tenter, corona discharge treatment was applied to the first surface layer, and the material was wound up on a winding machine to obtain the biaxially oriented polypropylene films of prototypes 4-6.

[0046] For prototypes 7-9, the following materials were kneaded and melted, and the layers were set to be laminated in the order of first surface layer, intermediate layer, and second surface layer. The mixture was co-extruded from a three-layer co-extrusion T-die film molding machine set to 240°C, cooled and solidified on a cooling roll at 50°C to obtain a sheet-like material that would become the raw material. Next, the sheet-like material was preheated to a set temperature of 100-110°C, stretched 4.8 times in the longitudinal (MD) direction, and then annealed at a set temperature of 130°C. In a tenter, it was preheated to a set temperature of 180°C, stretched 8.0 times in the transverse (TD) direction at a set temperature of 155°C, and then annealed at a set temperature of 160°C. After exiting the tenter, corona discharge treatment was applied to the first and second surface layers, and the material was wound up on a winding machine to obtain the biaxially oriented polypropylene films of prototypes 7-9.

[0047] For prototypes 10 and 11, the following materials were kneaded and melted, and the layers were set to be laminated in the order of first surface layer, intermediate layer, and second surface layer. The mixture was co-extruded from a three-layer co-extrusion T-die film molding machine set to 240°C, cooled and solidified on a cooling roll at 50°C to obtain a sheet-like material that would become the raw material. Next, the sheet-like material was preheated to a set temperature of 100-120°C, stretched 5.0 times in the longitudinal (MD) direction, and then annealed at a set temperature of 135°C. In a tenter, it was preheated to a set temperature of 180°C, stretched 8.0 times in the transverse (TD) direction at a set temperature of 160°C, and then annealed at a set temperature of 165°C. After exiting the tenter, corona discharge treatment was applied to the second surface layer, and the material was wound up on a winding machine to obtain the biaxially oriented polypropylene films of prototypes 10 and 11.

[0048] The biaxially oriented polypropylene films were fabricated with a thickness of 30 μm for prototypes 4-9 and 20 μm for the other prototypes.

[0049] [Materials used] • Polypropylene resin (PP-1): Biomass polypropylene (Lyondell Basell, 'C14 HP456J'), biomass content 46%, MFR (230℃ / 2.16kg) 3.4g / 10min, density 0.900g / cm³ 3 , melting point 165℃ · Polypropylene resin (PP-2): Petroleum-derived polypropylene (manufactured by 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°C · Polypropylene resin (PP-3): Petroleum-derived polypropylene (manufactured by 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°C · Polypropylene resin (PP-4): Petroleum-derived polypropylene (manufactured by 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°C · Polypropylene resin (PP-5): Petroleum-derived polypropylene (manufactured by 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°C · Polyethylene resin (PE-1): Biomass polyethylene (manufactured by 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°C · Polyethylene resin (PE-2): Petroleum-derived polyethylene (manufactured by 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°C

[0050] Powdered synthetic silica (manufactured by Fuji Silysia Chemical Ltd., 'Silicia 730') was appropriately added as an anti-blocking agent to the first surface layer and the second surface layer. An antistatic agent for polypropylene films was appropriately added to the intermediate layer.

[0051] The biomass content of the materials used was calculated by radiocarbon (C14) measurement 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 Example 1] The first surface layer was made with 100% by weight of resin (PP-2), the intermediate layer with 24% by weight of resin (PP-1) and 76% by weight of resin (PP-2), and the second surface layer with 100% by weight of resin (PP-2). The amount of raw materials discharged was adjusted so that the ratio of the first surface layer:intermediate layer:second surface layer was 1:18:1, and a biaxially oriented polypropylene film of prototype example 1 was obtained. The biomass content of the biaxially oriented polypropylene film of prototype example 1 was 9.9%.

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

[0054] [Prototype Example 3] The biaxially oriented polypropylene film of Prototype Example 3 was obtained by using the same method as in Prototype Example 1, except that the intermediate layer consisted 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 is 9.9%. The biomass content of Prototype Example 3 is derived from the polyethylene resin.

[0055] [Prototype Example 4] The first surface layer was made with 100% by weight of resin (PP-2), the intermediate layer with 30% by weight of resin (PP-1) and 70% by weight of resin (PP-2), and the second surface layer with 100% by weight of resin (PP-4). The amount of raw materials discharged was adjusted so that the ratio of the first surface layer:intermediate layer:second surface layer was 1:28:1, and the biaxially oriented polypropylene film of prototype example 4 was obtained. The biomass content of the biaxially oriented polypropylene film of prototype example 4 was 12.9%.

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

[0057] [Prototype Example 6] The process was the same as in Prototype Example 4, except that the intermediate layer consisted of 85% by weight of resin (PP-2) and 15% by weight of resin (PE-1), to obtain the biaxially oriented polypropylene film of Prototype Example 6. The biomass content of the biaxially oriented polypropylene film of Prototype Example 6 is 12.9%. The biomass content of Prototype Example 6 is derived from the polyethylene resin.

[0058] [Prototype Example 7] The first surface layer was made with 100% by weight of resin (PP-4), the intermediate layer with 24% by weight of resin (PP-1) and 76% by weight of resin (PP-2), and the second surface layer with 100% by weight of resin (PP-4). The amount of raw materials discharged was adjusted so that the ratio of the first surface layer:intermediate layer:second surface layer was 1:28:1, and the biaxially oriented polypropylene film of prototype example 7 was obtained. The biomass content of the biaxially oriented polypropylene film of prototype example 7 is 10.3%.

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

[0060] [Prototype Example 9] The process was the same as in Prototype Example 7, except that the intermediate layer consisted of 88% by weight of resin (PP-2) and 12% by weight of resin (PE-1), to obtain the biaxially oriented polypropylene film of Prototype Example 9. The biomass content of the biaxially oriented polypropylene film of Prototype Example 9 is 10.3%. The biomass content of Prototype Example 9 is derived from the polyethylene resin.

[0061] [Prototype Example 10] The first surface layer consisted of 30% by weight of resin (PP-3), 35% by weight of resin (PP-5), and 35% by weight of resin (PE-2). The intermediate layer consisted of 24% by weight of resin (PP-1) and 76% by weight of resin (PP-2). The second surface layer consisted of 100% by weight of resin (PP-4). The amount of raw materials discharged was adjusted so that the ratio of the first surface layer:intermediate layer:second surface layer was 2:17:1, and a biaxially oriented polypropylene film of prototype example 10 was obtained. The biomass content of the biaxially oriented polypropylene film of prototype example 10 was 9.4%.

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

[0063] For prototypes 1-11, haze (%), tensile breaking strength (MPa), tensile breaking elongation (%), and tensile modulus (GPa) were measured. For prototypes 1-9, surface gloss (%) and narrow-angle diffuse transmittance (LSI) (%) were also measured. Since prototypes 1-3 are base films for lamination, water vapor transmission (g / m²) was measured. 2 The heat shrinkage rate (%) was measured. Since prototypes 4-6 are heat-sealable films, the heat seal strength (N / 15mm) was measured. Since prototypes 7-9 are heat-sealable films, the heat-seal strength (N / 15mm) was measured. The resin ratio, biomass content, and measurement results for each layer of each prototype are shown in Tables 1-4.

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

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

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

[0067] [Measurement of surface gloss] Surface gloss (%) is an index indicating 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 indicator of transparency, representing the ratio of scattered light with a scattering angle of 0.4° to 1.2° to the total transmitted light. LSI is a measure of transparency to the naked eye, with lower values ​​indicating better transparency. LSI was measured using a visual transparency tester (manufactured by Toyo Seiki Seisakusho Co., Ltd.).

[0069] [Measurement of water vapor transmission rate] Water vapor transmission rate (g / m³) 2 The water vapor transmission rate (day) was measured in accordance with JIS K 7129 (2008) using a water vapor transmission rate measuring device (MOCON Corporation, 'PERMATRAN-W(registered trademark) 3 / 33') under conditions of a temperature of 40°C and a relative humidity of 90%.

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

[0071] [Measurement of thermal seal strength] The heat-seal strength (N / 15mm) was measured as follows. The bags were manufactured using heat sealing so that the second surface layer was on the inside of the bag. Sealing temperature: 400℃ Hot blade tip angle: 120℃ Cutting interval: 200 mm Shot rate: 72 frames / minute

[0072] Then, 20 bags were randomly selected from the obtained bag-like materials and subjected to measurement. Six test specimens, each 15 mm wide and 100 mm long, were cut from each side (three locations on each side) so that the two heat-sealed portions on each side of the bag-like material were centered. These test specimens were fixed with the chuck of a small benchtop testing machine (Shimadzu Corporation, 'EZ-SX'), and the chuck distance of the test specimens was adjusted to 50 mm. The machine was tensile at 200 mm / min, and the strength at which the heat-sealed portion broke was measured. The average value of the measured values ​​was defined as the heat-sealed strength (N / 15 mm).

[0073] [Table 1]

[0074] [Table 2]

[0075] [Table 3]

[0076] [Table 4]

[0077] [Results and Discussion] Prototypes 1-3 are intended for use as base films for lamination. In particular, since they are often used with printing on the laminate surface, transparency of the film is required. That is, a film is considered superior if the haze and narrow-angle diffuse transmittance (LSI) values, which are indicators of transparency, are low. As shown in Tables 1 and 3, there was almost no difference in various 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 consists only of petroleum-derived polypropylene. In other words, even Prototype 1, which showed values ​​equivalent to the haze and narrow-angle diffuse transmittance (LSI) of Prototype 2, a conventional petroleum-derived base film for lamination, was shown to be good as a base film for lamination. Therefore, it can be said that films using biomass polypropylene as a resin raw material have functionality that is no different from films made from conventional petroleum-derived polypropylene resin, and thus it is possible to reduce the environmental impact while maintaining the same usability as conventional films.

[0078] In prototype example 3, where biomass polyethylene is incorporated into the resin raw material, even with the same biomass content as prototype example 1, various physical properties are inferior. When used as a replacement for conventional films, it does not provide the same user experience and is unlikely to contribute to promoting the use of biomass resources. In particular, the narrow-angle diffuse transmittance (LSI) value is 20% or higher, resulting in a whitish appearance of the film and a tendency towards inferior design when printed on the laminated surface. The glossiness is also inferior, which is expected to worsen the appearance when used as packaging. Furthermore, the high water vapor permeability makes it unsuitable for packaging dry goods. In addition, the film has low mechanical strength, and especially a low tensile modulus, which means it may not meet the rigidity required for packaging and may be unsuitable for packaging. One possible reason for the reduced physical properties of the film is that polypropylene and polyethylene cannot be completely miscible, resulting in tiny islands of polyethylene dispersed in a sea of ​​polypropylene. Also, because it is a film made by mixing different types of resins, it is understood to be inferior to prototype example 1 from the perspective of film recycling (monomaterial).

[0079] Prototypes 4-6 are intended for use as single-sided heat-seal films. Prototypes 7-9 are intended for use as single-sided heat-seal films. Both types of films require good transparency and rigidity. As shown in Tables 1-4, there was almost no difference in various physical properties between Prototype 4, which contains biomass polypropylene in its resin raw material and has a biomass content of 12.9%, and Prototype 5, which consists only of petroleum-derived polypropylene. Similarly, there was almost no difference in various physical properties between Prototype 7, which has a biomass content of 10.3%, and Prototype 8, which consists only of petroleum-derived polypropylene. The haze and narrow-angle diffuse transmittance (LSI) values, 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 using 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 resin. Thus, it can be said that it is possible to reduce the environmental impact while maintaining the same feel as conventional films.

[0080] In prototypes 6 and 9, which contain biomass polyethylene as a resin raw material, even though they have the same biomass content as prototypes 4 and 7, they exhibit inferior physical properties. When used as a replacement for conventional films, they do not provide the same user experience, making them less effective in promoting the use of biomass resources. In particular, prototypes 6 and 9 show a narrow-angle diffuse transmittance (LSI) value of 20% or higher, resulting in a whitish appearance and a tendency towards inferior aesthetic appeal when used alone. Their inferior gloss also suggests a poor appearance when used as packaging. Furthermore, the films have low mechanical strength, especially a low tensile modulus, which may prevent them from meeting the required rigidity for packaging and thus compromise their packaging suitability. The reason for the reduced physical properties of the films is thought to be that polypropylene and polyethylene cannot completely mix, resulting in the micro-dispersion of polyethylene "islands" within a sea of ​​polypropylene. Additionally, because these films are made from a mixture of different types of resins, they are inferior to prototypes 4 and 7 from the perspective of film recycling (monomaterial).

[0081] Prototypes 10 and 11 are intended for use as matte-finish base films for lamination. Generally, matte-finish biaxially oriented polypropylene films often require high design quality, such as for packaging expensive confectionery, due to their unique texture. Not only the appearance but also a luxurious feel is often desired. As shown in Tables 2 and 4, there was almost no difference in various 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 consists only of petroleum-derived polypropylene. Therefore, it can be said that films using biomass polypropylene as a resin raw material have functionality that is no different from conventional films made of petroleum-derived polypropylene resin. Thus, it can be said that it is possible to reduce the environmental impact while maintaining the same high texture and feel as conventional films.

[0082] [Preparation of unstretched film] Using the polypropylene resin and polyethylene resin described below, unoriented polypropylene films (Prototype Examples 12-18) and unoriented polyethylene films (Prototype Examples 19-22) were created. Prototype Examples 19-22 are laminated films that have a polypropylene film as one or two resin layers. The unoriented polypropylene films of Prototype Examples 12-15 are intended to be used as general-purpose laminating sealant films, while the unoriented polypropylene films of Prototype Examples 16-18 are intended to be used as easy-peel laminating sealant films. The unoriented polyethylene films of Prototype Examples 19 and 20 are intended to be used as standalone films that are heat-sealed. The unoriented polyethylene films of Prototype Examples 21 and 22 are intended to be used as matte surface substrates. Note that Prototype Examples 19-22 are laminated films that have a polypropylene film as a resin layer in the first or second surface layer. The following materials were melted and kneaded, then co-extruded using a T-die film molding machine and cooled with a cooling roll to produce an unstretched film. The unstretched films for each prototype were produced 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 (manufactured by Nippon Polypropylene Co., Ltd., 'FB3B'), biomass content 0%, MFR (230℃ / 2.16kg) 7.5g / 10min, density 0.900g / cm³ 3 , melting point 163℃ • Polyethylene resin (PE-2) • Polyethylene resin (PE-3): Biomass polyethylene (BLASCHEM, 'SLH218'), biomass content 92%, MFR (190℃ / 2.16kg) 2.3g / 10min, density 0.916g / cm³ 3 , melting point 125℃ • Polyethylene resin (PE-4): Petroleum-derived polyethylene (manufactured by Prime Polymer Co., Ltd., 'SP2040'), biomass content 0%, MFR (190℃ / 2.16kg) 3.8g / 10min, density 0.918g / cm³ 3 , melting point 116℃ • Polyethylene resin (PE-5): Petroleum-derived polyethylene (manufactured by Ube Maruzen Polyethylene Co., Ltd., 'F222NH'), biomass content 0%, MFR (190℃ / 2.16kg) 2.0g / 10min, density 0.922g / cm³ 3 Melting point 110℃

[0084] Powdered synthetic silica (manufactured by Fuji Silysia Co., Ltd., "Silysia 430") was appropriately added as an antiblocking agent to the first and second surface layers. A slip agent for polypropylene films was appropriately added to the intermediate layer.

[0085] [Prototype Example 12] The first surface layer was made of 100% by weight of resin (PP-3), the intermediate layer of 75% by weight of resin (PP-3) and 25% by weight of resin (PP-6), and the second surface layer of 100% by weight of resin (PP-4). The amount of raw materials discharged was adjusted so that the ratio of the first surface layer:intermediate layer:second surface layer was 1:4:1, and the film thickness was 30 μm to obtain the unoriented polypropylene film of prototype example 12. The biomass content of the unoriented polypropylene film of prototype example 12 is 0%.

[0086] [Prototype Example 13] The process was the same as in Prototype Example 12, except that the intermediate layer consisted of 60% by weight of resin (PP-1) and 40% by weight of resin (PP-3), to obtain Prototype Example 13, an unoriented polypropylene film. The biomass content of the unoriented polypropylene film of Prototype Example 13 is 18.4%.

[0087] [Prototype Example 14] The same procedure as in Prototype Example 12 was followed, except that the first surface layer consisted of 25% by weight of resin (PP-1) and 75% by weight of resin (PP-3), to obtain Prototype Example 14, an unoriented polypropylene film. The biomass content of the unoriented polypropylene film of Prototype Example 14 is 1.9%.

[0088] [Prototype Example 15] The same procedure as in Prototype Example 12 was followed, except that the first surface layer consisted of 87.5% by weight of resin (PP-3) and 12.5% ​​by weight of resin (PE-3), to obtain Prototype Example 15, an unoriented polypropylene film. The biomass content of the unoriented polypropylene film of Prototype Example 15 is 1.9%. The biomass content of Prototype Example 15 is derived from the polyethylene resin.

[0089] [Prototype Example 16] The first surface layer was made of 80% by weight of resin (PE-4) and 20% by weight of resin (PE-5), and the intermediate layer was made of 100% by weight of resin (PP-6). The amount of raw materials discharged was adjusted so that the ratio of the first surface layer:intermediate layer:second surface layer was 1:2:1, and the film thickness was set to 20 μm. Except for these factors, the process was the same as in Prototype Example 12 to obtain Prototype Example 16, an unoriented polypropylene film. The biomass content of the unoriented polypropylene film of Prototype Example 16 is 0%.

[0090] [Prototype Example 17] The same procedure as in Prototype Example 16 was followed, except that the first surface layer was made of 100% by weight of resin (PE-4), and the intermediate layer consisted of 50% by weight of resin (PP-1) and 50% by weight of resin (PP-6), to obtain the unoriented polypropylene film of Prototype Example 17. The biomass content of the unoriented polypropylene film of Prototype Example 17 is 11.5%.

[0091] [Prototype Example 18] The process was the same as in Prototype Example 16, except that the intermediate layer consisted of 50% by weight of resin (PP-1) and 50% by weight of resin (PP-3), to obtain Prototype Example 18, an unoriented polypropylene film. The biomass content of the unoriented polypropylene film of Prototype Example 18 is 11.5%.

[0092] [Prototype Example 19] The process was the same as in Prototype Example 12, except that the intermediate 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), to obtain Prototype Example 19, an unoriented polyethylene film. The biomass content of the unoriented polyethylene film of Prototype Example 19 is 0%.

[0093] [Prototype Example 20] The same procedure as in Prototype Example 19 was followed, except that the first and second surface layers were made of resin (PP-1) 25% by weight and (PP-3) 75% by weight, to obtain Prototype Example 20, an unoriented polyethylene film. The biomass content of the unoriented polyethylene film of Prototype Example 20 is 3.8%.

[0094] [Prototype Example 21] 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 intermediate layer was made of 100% by weight of resin (PE-4), and the second surface layer was made of 100% by weight of resin (PE-4). Except for these differences, the process was the same as in Prototype Example 12, to obtain Prototype Example 21, an unoriented polyethylene film. The biomass content of the unoriented polyethylene film of Prototype Example 21 was 0%.

[0095] [Prototype Example 22] The same procedure as in Prototype Example 21 was followed, except that the first surface layer consisted of 30% by weight of resin (PP-1), 35% by weight of resin (PP-5), and 35% by weight of resin (PE-2), to obtain Prototype Example 22, an unoriented polyethylene film. The biomass content of the unoriented polyethylene film of Prototype Example 22 is 2.3%.

[0096] For prototypes 12-22, haze (%), tensile yield strength (MPa), tensile breaking strength (MPa), tensile breaking elongation (%), tensile modulus (GPa), and heat seal start temperature (°C) were measured. Since prototypes 12-15 are intended for use as laminating sealant films and therefore require transparency, narrow-angle diffuse transmittance (LSI) (%) was measured. For prototypes 16-18, since they are intended for use as laminating easy-peel films, their easy-peel suitability was evaluated. For prototypes 19 and 20, since they are films for heat sealing, the heat sealing strength (N / 15mm) was measured. The resin ratio for each layer, biomass content, and the measurement results for each prototype are shown in Tables 5-10. Note that for prototypes 19-22, since polyethylene films do not have a yield point, tensile yield strength (MPa) was not measured and is indicated as "-" in the table. Furthermore, since prototypes 21 and 22 are matte films intended for surface substrate applications, the heat sealing start temperature has not been measured.

[0097] [Measurement of haze] The haze (%) was measured in the same way as for biaxially oriented polypropylene films.

[0098] [Tensile properties] The tensile yield strength (MPa), tensile breaking strength (MPa), tensile breaking elongation (%), and tensile modulus (GPa) in the longitudinal (MD) and transverse (TD) directions of the film were measured using a tensile testing machine (Orientec Co., Ltd., 'RTF-1310') in accordance with JIS K 7127 (1999), similar to the measurements for the biaxially oriented polypropylene film described above.

[0099] [Measurement of heat seal start temperature] The heat seal start temperature (°C) is one of the indicators 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 (horizontal (TD) direction x vertical (MD) direction of the film). The sealant layers (second surface layer) of two test pieces were overlapped, and a heat seal test machine (manufactured by Toyo Seiki Seisakusho Co., Ltd., "Thermal Gradient Test Machine") was used, with a heat seal pressure of 0.4 MPa and a heat seal time of 1 second. The heat seal was then performed under conditions where the temperature was increased in increments of 5°C. At this time, a cellophane film to prevent fusion was placed between the heat plate of the heat sealer and the test piece film. The heat-sealed test piece was opened to 180°, and the unsealed portion was clamped in a chuck using a small benchtop test machine (manufactured by Shimadzu Corporation, "EZ-SX"), and the sealed portion was peeled off in a T-shape. Then, the temperature at which the heat seal strength reaches 3 (N / 15mm) was interpolated to determine the result.

[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 Co., Ltd.), similar to the measurement performed on the biaxially oriented polypropylene film described above.

[0101] [Suitable for Easy Peel] Easy-peel suitability was evaluated as an indicator of ease of opening when used as a lid for bags or containers, using the following method. Corona discharge treatment was performed on the surface of the first surface layer of prototypes 16 to 18, a polyester-based dry laminating adhesive was applied, and a 15 μm biaxially oriented nylon film was bonded to it to form a laminated film. The laminated film was then cut into rectangular test pieces (for heat sealing) measuring 50 mm x 250 mm (horizontal (TD) direction x vertical (MD) direction of the film). The second surface layers (heat-seal layers) of the cut test pieces were stacked together, and heat sealing was performed using a heat-seal testing machine (manufactured by Toyo Seiki Seisakusho Co., Ltd., "Thermal Gradient Testing Machine") under the conditions of a heat-seal pressure of 0.4 MPa, a heat-seal time of 1 second, and a set temperature of 150 °C. A 15mm wide section was cut from the center of the heat-sealed test piece, and it was opened to 180°. The unsealed portion was then clamped in a chuck using a small benchtop testing machine (Shimadzu Corporation, 'EZ-SX'), and the seal was peeled in a T-shape at a tensile speed of 200m / min to measure the seal strength. Furthermore, the peeled surface of the measured sample was observed to confirm that peeling was progressing inside the film of the prototype example. A seal strength of 1-15N / 15mm and peeling progressing inside the film were marked as "○", and all others were marked as "×". Films marked as "×" were likely to break or were difficult to open, and therefore did not possess the suitability for easy peeling.

[0102] [Measurement of thermal seal strength] The heat-seal strength (N / 15mm) was measured in the same manner as the measurement for the biaxially oriented polypropylene film described above, except that the heat-sealing conditions were 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 12-15 are intended for use as sealant films for lamination. As shown in Tables 5 and 8, there was almost no difference in various 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 consists only of petroleum-derived polypropylene. In particular, transparency of the film is required because printing on the laminate surface is expected. That is, a film is considered superior if the values ​​of haze and narrow-angle diffuse transmittance (LSI), which are indicators of transparency, are low. As shown in Table 8, prototypes 13 and 14 showed values ​​equivalent to prototype 12, indicating that both are good as sealant films for lamination. In other words, regardless of which layer biomass polypropylene is incorporated into as a resin raw material, the characteristics of the film do not change significantly compared to when petroleum-derived polypropylene is used, and the ease of use, feel, and handling remain the same. For this reason, it has been shown to be a promising alternative to conventional petroleum-derived films.

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

[0111] Prototypes 16-18 are intended for use as easy-peel films for lamination. As shown in Tables 6 and 9, prototypes 17 and 18 showed comparable easy-peel properties to prototype 16 even when 50% of the intermediate layer was replaced with biomass polypropylene. In other words, regardless of which layer biomass polypropylene is incorporated as the resin raw material, the film's properties do not change significantly compared to when petroleum-derived polypropylene is used, and the ease of use, feel, and handling remain the same. Therefore, it has been shown to be a promising alternative to conventional petroleum-derived films.

[0112] Prototypes 19 and 20 are intended for use as standalone heat-seal films. The addition of a polyethylene layer in the middle layer enables packaging of heavy objects. As shown in Tables 7 and 10, in prototype 20, replacing 25% of the first and second surface layers with biomass polypropylene resulted in heat-seal strength comparable to prototype 19. In other words, regardless of which layer biomass polypropylene is incorporated as the resin raw material, the film's properties do not change significantly compared to when petroleum-derived polypropylene is used, and its ease of use, feel, and handling remain the same. Therefore, it has been shown to be a promising alternative to conventional petroleum-derived films.

[0113] Prototypes 21 and 22 are intended for use as matte-finish films for surface substrates. As shown in Tables 7 and 10, in prototype 22, replacing 30% of the first surface layer with biomass polypropylene resulted in a matte appearance comparable to prototype 21. In other words, regardless of which layer biomass polypropylene is incorporated as a resin raw material, the film's properties do not change significantly compared to when petroleum-derived polypropylene is used, and its ease of use, feel, and handling remain the same. Therefore, it has been shown to be a promising alternative to conventional petroleum-derived films. [Industrial applicability]

[0114] This invention of The film is made from a resin raw material containing biomass polypropylene produced from bio-naphtha obtained from plant-derived oils and propylene made from bio-propane. This reduces the environmental impact while suppressing the deterioration of the film's performance, making it a promising alternative to conventional films. [Explanation of Symbols]

[0115] 10-layer film 11 First surface layer 12 Second surface layer 13. Middle Class

Claims

1. A transparent film for single-sided heat sealing or heat-sealing, which is a polypropylene-based film made from a resin raw material mainly composed of polypropylene, The resin raw material is a 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, It contains petroleum-derived polypropylene, The biomass content of the aforementioned polypropylene film is 5% or more. The biomass content of the aforementioned biomass polypropylene, as measured by radiocarbon dating, is 5% or more, and The melt flow rate (230°C, 2.16 kg load) is 0.1 to 50 g / 10 min. Density of 0.850–0.910 g / cm³ ３ That is A transparent film characterized by the following features.

2. A laminated film comprising a plurality of resin layers, including the transparent film described in claim 1.

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