Resin film, laminate and bag

Abstract

To provide a resin film having reduced environmental load, and having excellent drop impact resistance, retort resistance, appearance, sealability and functionality, and a laminate and a bag.SOLUTION: A resin film is a single layer. The resin film has a propylene-ethylene block copolymer as the main component and further has a thermoplastic elastomer and polyethylene with a density of 925 kg / m3 or less. The polyethylene includes linear low-density polyethylene. The polyethylene includes biomass polyethylene. The resin film has a biomass level of 27% or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a resin film, a laminate, and a bag. [Background technology]

[0002] Bags made of polyolefin resin films such as polyethylene resin and polypropylene resin are inexpensive and are widely used in a variety of fields. For example, polyolefin resin films are used in the field of retort pouches, in which contents such as food are placed in the bag, sealed, and then subjected to a heat and pressure treatment (retort treatment).

[0003] In the field of retort pouches, polyolefin resin films are used particularly for sealant layers, and are required to have impact resistance and retort resistance. Patent Document 1 proposes a retort pouch sealant film that has excellent impact resistance and retort resistance, and this retort pouch sealant film is composed of a mixture of random copolymer polypropylene and a polypropylene-based soft resin.

[0004] In recent years, there has been a global demand for a reduction in carbon dioxide emissions in order to curb global warming. As with energy, there is a desire to move away from fossil fuels in the materials field, and the use of biomass has been attracting attention. Biomass is an organic compound formed by photosynthesis from carbon dioxide and water, and by utilizing it, it can be converted back into carbon dioxide and water, making it a so-called carbon-neutral renewable energy source. Recently, the practical application of biomass plastics made from biomass has progressed rapidly, and attempts are being made to produce various resins from biomass raw materials.

[0005] Regarding the polypropylene resin used in retort pouches, biomass polypropylene resin made from biomass has been put on the market. However, biomass polypropylene resin is significantly more expensive than fossil fuel polypropylene, and is therefore not very practical. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 8-302110 Summary of the Invention [Problem to be solved by the invention]

[0007] The inventors of the present invention considered reducing the amount of fossil fuel-derived polypropylene resin used and the environmental impact by substituting a portion of the fossil fuel-derived polypropylene resin with relatively inexpensive biomass polyethylene. However, resin films made by blending fossil fuel-derived polypropylene resin and biomass polyethylene resin have problems with appearance, drop impact resistance, retort resistance, and sealability, and furthermore, new problems have arisen in that the odor specific to biomass materials affects the contents.

[0008] The present invention has been made in view of the above problems, and an object of the present invention is to provide a resin film, a laminate, and a bag that have a reduced environmental impact and are excellent in drop impact resistance, retort resistance, appearance, sealability, and functionality. [Means for solving the problem]

[0009] The present invention relates to a single-layer resin film, the resin film comprising a propylene-ethylene block copolymer as a main component, a thermoplastic elastomer, and a polymer having a density of 925 kg / m 3 The resin film comprises the following polyethylene, wherein the polyethylene comprises linear low-density polyethylene, the polyethylene comprises biomass polyethylene, and the biomass ratio of the resin film is 27% or less.

[0010] In the resin film according to the present invention, the biomass ratio of the resin film may be 23% or less.

[0011] In the resin film according to the present invention, the resin film may have a content of the propylene-ethylene block copolymer, a content of the linear low-density polyethylene, and a content of the thermoplastic elastomer in this order.

[0012] In the resin film according to the present invention, the polyethylene may include biomass linear low-density polyethylene.

[0013] In the resin film according to the present invention, the breaking elongation in one direction and in another direction perpendicular to the one direction may each be 500% or more.

[0014] The present invention is a laminate comprising at least one biaxially oriented plastic film and a resin film according to the present invention.

[0015] The present invention is a bag comprising a laminate according to the present invention. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide a resin film, laminate and bag that have reduced environmental impact and are excellent in drop impact resistance, retort resistance, appearance, sealability and functionality. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a cross-sectional view showing an example of the resin film of the present invention. [Figure 2] FIG. 2 is a cross-sectional view showing an example of the laminate of the present invention. [Figure 3] FIG. 3 is a cross-sectional view showing another example of the laminate of the present invention. [Figure 4] FIG. 4 is a cross-sectional view showing another example of the laminate of the present invention. [Figure 5] FIG. 5 is a cross-sectional view showing another example of the laminate of the present invention. [Figure 6] FIG. 6 is a front view showing the bag of the present invention. [Figure 7]FIG. 7 is an exploded view showing the film that constitutes the bag shown in FIG. [Figure 8] FIG. 8 is a diagram showing the cutting out of a test piece for measuring the seal strength of the bag of the present invention. [Figure 9] FIG. 9 is a diagram showing how the seal strength is measured using a test piece. DETAILED DESCRIPTION OF THE INVENTION

[0018] An embodiment of the present invention will be described with reference to Figures 1 to 9. In the drawings accompanying this specification, the scale and aspect ratios have been appropriately changed and exaggerated from those of the actual objects for the sake of illustration and ease of understanding.

[0019] Furthermore, terms used in this specification that specify shapes, geometric conditions, and their degrees, such as "parallel," "orthogonal," and "identical," as well as values ​​of lengths and angles, are not to be construed as being bound by strict meanings, but rather as including a range within which similar functions can be expected.

[0020] Resin film Fig. 1 is a cross-sectional view showing an example of a resin film 10 of the present invention. As shown in Fig. 1, the resin film 10 is a single layer.

[0021] The resin film contains a propylene-ethylene block copolymer as a main component. In this specification, "containing a propylene-ethylene block copolymer as a main component" means that the resin film contains more than 50 mass % of the propylene-ethylene block copolymer. "Propylene-ethylene block copolymer" refers to a material having the structural formula shown in formula (I) below. In formula (I), m1, m2, and m3 represent integers of 1 or greater. In this specification, unless otherwise specified, the "propylene-ethylene block copolymer" is obtained from a raw material derived from a fossil fuel.

[0022] [ka]

[0023] The use of a propylene-ethylene block copolymer can improve the drop impact resistance of the resin film. This can prevent the bag from breaking due to the impact of being dropped when a laminate including the resin film is produced into a bag. It can also improve the puncture resistance of the resin film.

[0024] The propylene-ethylene block copolymer contains, for example, a sea component made of polypropylene and island components made of an ethylene-propylene copolymer rubber component. The sea component can contribute to improving the blocking resistance, heat resistance, rigidity, seal strength, etc. of the propylene-ethylene block copolymer. The island components can also contribute to improving the drop impact resistance of the propylene-ethylene block copolymer. Therefore, by adjusting the ratio of the sea component to the island components, the mechanical properties of a resin film containing the propylene-ethylene block copolymer can be adjusted.

[0025] In the propylene-ethylene block copolymer, the mass ratio of the sea part made of polypropylene is higher than the mass ratio of the island part made of ethylene-propylene copolymer rubber component. For example, in the propylene-ethylene block copolymer, the mass ratio of the sea part made of polypropylene is at least 51 mass% or more, preferably 60 mass% or more, and more preferably 70 mass% or more.

[0026] Propylene-ethylene block copolymers can be produced by polymerizing raw materials such as propylene and ethylene using a catalyst, such as a Ziegler-Natta catalyst or a metallocene catalyst.

[0027] The resin film further contains a thermoplastic elastomer. The use of the thermoplastic elastomer can further enhance the drop impact resistance and puncture resistance of the resin film. Furthermore, the resistance to orange peel and whitening can be improved, resulting in a good appearance.

[0028] Here, "citrus peel resistance" refers to the prevention of the citrus peel phenomenon. The citrus peel phenomenon is a phenomenon in which unevenness occurs on the surface of a film after retorting an oily food such as curry, and is considered a problem in appearance. The cause of the citrus peel phenomenon is that when the oil contained in the retort food penetrates and diffuses into the inner sealant layer, swelling occurs in the rubber component used to improve impact resistance in the resin that makes up the sealant layer. If the dispersed particle size of the rubber component is large, uneven swelling occurs, and this uneven swelling of the rubber component causes fine unevenness in the film, resulting in the appearance that looks like citrus peel.

[0029] The thermoplastic elastomer preferably contains a hydrogenated styrene-based thermoplastic elastomer, and more preferably is composed of a hydrogenated styrene-based thermoplastic elastomer. This can further improve drop impact resistance, retort resistance, appearance, and sealability. The hydrogenated styrene-based thermoplastic elastomer has a structure consisting of a polymer block A mainly composed of at least one vinyl aromatic compound and a polymer block B mainly composed of at least one hydrogenated conjugated diene compound. As the hydrogenated styrene-based thermoplastic elastomer, a styrene-ethylene / butylene-styrene block copolymer (SEBS) is preferably used. The thermoplastic elastomer may also contain an ethylene-α-olefin elastomer. The ethylene-α-olefin elastomer is a low-crystalline or amorphous copolymer elastomer, and is a random copolymer of 50 to 90% by mass of ethylene as the main component and an α-olefin as a copolymerization monomer.

[0030] The resin film further contains a second thermoplastic resin in addition to the first thermoplastic resin made of a propylene-ethylene block copolymer. The second thermoplastic resin has a density of 925 kg / m 3 The second thermoplastic resin is composed of the following polyethylene. The second thermoplastic resin can improve the drop impact resistance of the resin film and contribute to obtaining a good appearance. The polyethylene constituting the second thermoplastic resin may be composed of one type of polyethylene alone, or may be a resin composition containing two or more types of polyethylene.

[0031] In the resin film of the present invention, the polyethylene constituting the second thermoplastic resin contains linear low-density ethylene, which can improve retort resistance and sealability. Linear low-density polyethylene has good adhesion to the polypropylene, which is the sea component of the propylene-ethylene block copolymer, and can therefore prevent peeling between the resins of the resin film. Linear low-density polyethylene is a copolymer of ethylene and α-olefins polymerized using a multi-site catalyst such as a Ziegler-Natta catalyst or a single-site catalyst such as a metallocene catalyst, and has a density of 925 kg / m 3 The term "density" refers to the following: Examples of α-olefins that serve as comonomers for linear low-density polyethylene include α-olefins having 3 to 20 carbon atoms, such as propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-nonene, 4-methylpentene, and mixtures thereof. Here, the density of polyethylene is a value measured according to the method specified in Method A of JIS K7112-1980 after annealing as specified in JIS K6760-1995.

[0032] The polyethylene constituting the second thermoplastic resin may include high-density polyethylene, medium-density polyethylene, and low-density polyethylene, as long as the properties of the present invention are not impaired. 3 Medium density polyethylene refers to polyethylene with a density exceeding 925 kg / m3 Super 942kg / m 3 Low-density polyethylene, which can also be called high-pressure low-density polyethylene, is a high-pressure ethylene homopolymer that can be obtained by a conventionally known high-pressure radical polymerization method and has a density of 925 kg / m or less. 3 It is polyethylene having the following density:

[0033] The polyethylene constituting the second thermoplastic resin contains biomass polyethylene. This allows for a reduction in the amount of fossil fuel used and a reduction in the environmental impact. Examples of biomass polyethylene include biomass high-density polyethylene, biomass medium-density polyethylene, biomass high-pressure low-density polyethylene, and biomass linear low-density polyethylene.

[0034] Furthermore, the resin film of the present invention has a biomass degree of 27.0% or less. This reduces the effects of odors specific to biomass materials and deterioration of taste, resulting in a resin film with excellent functionality. From the viewpoint of functionality, the biomass degree of the resin film is preferably 23.0% or less. Moreover, from the viewpoint of reducing the environmental load, the biomass degree of the resin film is preferably 1.0% or more, more preferably 5.0% or more, and even more preferably 10.0% or more.

[0035] The polyethylene constituting the second thermoplastic resin may contain fossil fuel polyethylene, such as fossil fuel high-density polyethylene, fossil fuel medium-density polyethylene, fossil fuel high-pressure low-density polyethylene, and fossil fuel linear low-density polyethylene, as long as the properties of the present invention are not impaired.

[0036] <Biomass-derived ethylene> The method for producing biomass-derived ethylene, which is the raw material for biomass polyethylene, is not particularly limited, and it can be obtained by a conventionally known method. An example of a method for producing biomass-derived ethylene will be described below.

[0037] Biomass-derived ethylene can be produced using biomass-derived ethanol as a raw material. In particular, it is preferable to use biomass-derived fermented ethanol obtained from plant raw materials. The plant raw material is not particularly limited, and conventionally known plants can be used. Examples include corn, sugarcane, beet, and manioc.

[0038] Fermented ethanol derived from biomass refers to ethanol produced by contacting a culture solution containing a carbon source obtained from plant raw materials with an ethanol-producing microorganism or a product derived from its disruption, followed by purification. Ethanol can be purified from the culture solution by conventional methods such as distillation, membrane separation, and extraction. Examples of methods include adding benzene, cyclohexane, etc., followed by azeotropy, or removing water by membrane separation.

[0039] In order to obtain the above ethylene, further advanced purification may be carried out at this stage, for example, to reduce the total amount of impurities in the ethanol to 1 ppm or less.

[0040] A catalyst is usually used when obtaining ethylene by the dehydration reaction of ethanol, but the catalyst is not particularly limited and any conventionally known catalyst can be used. From the viewpoint of the process, a fixed-bed flow reaction is advantageous because it allows easy separation of the catalyst and the product, and for example, γ-alumina is preferred.

[0041] Since this dehydration reaction is an endothermic reaction, it is usually carried out under heated conditions. The heating temperature is not limited as long as the reaction proceeds at a commercially useful reaction rate, but is preferably 100°C or higher, more preferably 250°C or higher, and even more preferably 300°C or higher. There is no particular upper limit, but from the viewpoint of energy balance and equipment, it is preferably 500°C or lower, more preferably 400°C or lower.

[0042] In the dehydration reaction of ethanol, the yield of the reaction depends on the amount of water contained in the ethanol supplied as a raw material. Generally, when performing a dehydration reaction, it is preferable to eliminate water in order to improve the efficiency of water removal. However, in the case of ethanol dehydration using a solid catalyst, it has been found that the absence of water tends to increase the amount of other olefins, particularly butene, produced. This is presumably because the presence of a small amount of water is insufficient to suppress ethylene dimerization after dehydration. The allowable lower limit of the water content is 0.1% by mass or more, preferably 0.5% by mass or more. There are no particular limitations on the upper limit, but from the viewpoints of material balance and heat balance, it is preferably 50% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less.

[0043] By carrying out the dehydration reaction of ethanol in this manner, a mixture of ethylene, water, and a small amount of unreacted ethanol is obtained, but since ethylene is in a gaseous state at room temperature and below about 5 MPa, water and ethanol can be removed from this mixture by gas-liquid separation to obtain ethylene. This can be done by a known method.

[0044] The ethylene obtained by the gas-liquid separation is further distilled. The distillation method, operation temperature, residence time, etc. are not particularly limited, except that the operation pressure at this time must be atmospheric pressure or higher.

[0045] When biomass-derived ethanol is used as the raw material, the resulting ethylene contains trace amounts of impurities introduced during the ethanol fermentation process, such as carbonyl compounds (e.g., ketones, aldehydes, and esters) and their decomposition products (e.g., carbon dioxide), as well as nitrogen-containing compounds (e.g., amines and amino acids) and their decomposition products (e.g., ammonia), which are enzymatic decomposition products and contaminants. Depending on the intended use of ethylene, these trace amounts of impurities may be problematic, so they may be removed by purification. The purification method is not particularly limited, and conventionally known methods can be used. An example of a suitable purification procedure is adsorption purification. The adsorbent used is not particularly limited, and conventionally known adsorbents can be used. For example, a material with a high surface area is preferred, and the type of adsorbent is selected depending on the type and amount of impurities in the ethylene obtained by the dehydration reaction of biomass-derived ethanol.

[0046] A caustic water treatment may be used in combination as a method for purifying impurities in ethylene. When caustic water treatment is used, it is desirable to carry out the treatment before adsorption purification. In this case, it is necessary to carry out a water removal treatment after the caustic treatment and before adsorption purification.

[0047] <Biomass polyethylene> Biomass polyethylene is formed by polymerizing a monomer containing biomass-derived ethylene. It is preferable to use biomass-derived ethylene obtained by the above-mentioned production method. Since biomass-derived ethylene is used as the raw material monomer, the polymerized polyethylene is derived from biomass. When the biomass polyethylene is biomass linear low-density polyethylene, it is polyethylene polymerized by the above-mentioned polymerization method using biomass-derived ethylene. As the biomass polyethylene, for example, SLL118 (density: 916 kg / m), a linear low-density polyethylene manufactured by Braskem, can be used. 3 The raw material monomer for polyethylene does not have to contain 100% by mass of biomass-derived ethylene.

[0048] As long as the object of the present invention is not impaired, the monomers that are raw materials for biomass polyethylene may further contain ethylene derived from fossil fuels.

[0049] In the present invention, the "biomass content" is expressed as the weight ratio of biomass-derived components.

[0050] Atmospheric carbon dioxide contains a certain proportion of C14 (105.5 pMC), and it is known that the C14 content in plants that grow by absorbing atmospheric carbon dioxide, such as corn, is also approximately 105.5 pMC. It is also known that fossil fuels contain very little C14. Therefore, the proportion of biomass-derived carbon can be calculated by measuring the proportion of C14 in the total carbon atoms. In the present invention, "biomass ratio" refers to the weight ratio of biomass-derived components. For example, in the case of polyethylene terephthalate, which is a polymer of ethylene glycol containing two carbon atoms and terephthalic acid containing eight carbon atoms in a 1:1 molar ratio, if only biomass-derived ethylene glycol is used, the weight ratio of biomass-derived components in the polyester is 31.25%, resulting in a theoretical biomass ratio of 31.25%. Specifically, the mass of polyethylene terephthalate is 192, of which the mass derived from biomass-derived ethylene glycol is 60, so 60 ÷ 192 × 100 = 31.25. Furthermore, the weight ratio of biomass-derived components in a fossil fuel-derived polyester produced using fossil fuel-derived ethylene glycol and fossil fuel-derived dicarboxylic acid is 0%, and the biomass content of the fossil fuel-derived polyester is 0%. Hereinafter, unless otherwise specified, "biomass content" refers to the weight ratio of biomass-derived components.

[0051] In the present invention, theoretically, if all biomass-derived ethylene is used as a raw material for polyethylene, the concentration of biomass-derived ethylene will be 100%, and the biomass content of biomass polyethylene will be 100%.Furthermore, the concentration of biomass-derived ethylene in fossil fuel polyethylene produced only from fossil fuel-derived raw materials will be 0%, and the biomass content of fossil fuel polyethylene will be 0%.

[0052] In the present invention, the biomass polyethylene or biomass-derived resin layer does not need to have a biomass content of 100%. This is because if even a part of the resin film uses biomass-derived raw materials, it is in line with the purpose of reducing the amount of fossil fuel used compared to conventional methods.

[0053] The resin film is a propylene-ethylene block copolymer with a density of 925 kg / m 3 The content of the following polyethylene is preferably greatest, followed by the thermoplastic elastomer. In addition, in the resin film, the mass ratio of the first thermoplastic resin made of a propylene-ethylene block copolymer is preferably 100% or more when the density is 925 kg / m 3 It is preferable that the mass ratio of the second thermoplastic resin be higher than that of the polyethylene having a density of 925 kg / m 3 The mass ratio of the polyethylene below is preferably higher than the mass ratio of the thermoplastic elastomer.

[0054] In the resin film, the mass ratio of the first thermoplastic resin made of a propylene-ethylene block copolymer is at least more than 50 mass%, preferably 60 mass% or more, and more preferably 70 mass% or more. In addition, the density of the resin film is 925 kg / m 3 The mass ratio of the polyethylene below is preferably 10% by mass or more and 30% by mass or less, more preferably 15% by mass or more and 25% by mass or less. Furthermore, in the resin film, the mass ratio of the thermoplastic elastomer is preferably 3 mass % or more and 20 mass % or less, and more preferably 3 mass % or more and 15 mass % or less.

[0055] The thickness of the resin film is preferably 30 μm or more, more preferably 40 μm or more, and even more preferably 60 μm or more.

[0056] Furthermore, the resin film preferably has a breaking elongation of 500% or more in one direction and in the other direction perpendicular to the one direction. The breaking elongation of the resin film in the present invention is measured in accordance with JIS K7127. Using a Tensilon universal material testing machine RTC-1310A (manufactured by A&D Co., Ltd.), the test piece is held for 1 minute in an environment at a temperature of 25°C and a relative humidity of 50%, and then measurement is performed under an environment at a temperature of 25°C and a relative humidity of 50%. Measurements are performed using rectangular test pieces with a side length of 15 mm and a direction perpendicular to the side length of 150 mm, with an initial gripping distance of 100 mm and a tensile speed of 300 mm / min. The length in the direction perpendicular to the side can be adjusted as long as the measurement can be performed with an initial gripping distance of 100 mm.

[0057] For example, the breaking elongation (%) of the resin film in the machine direction (MD) is preferably 500% or more, more preferably 700% or more, and even more preferably 800% or more. Furthermore, for example, the breaking elongation of the resin film in the transverse direction (TD) perpendicular to the machine direction is preferably 500% or more. The breaking elongation of the resin film in the transverse direction (TD) is preferably 700% or more, more preferably 800% or less, and even more preferably 900% or more.

[0058] The one direction mentioned above may be a direction different from the machine direction (MD) or the perpendicular direction (TD).

[0059] The resin film of the present invention is preferably used as a sealant layer because of its excellent drop impact resistance, sealability, and functionality, and is more preferably used as a sealant layer for retort pouches because of its excellent retort resistance and appearance.

[0060] (Method of manufacturing resin film) The method for producing the resin film of the present invention is not particularly limited, and can be produced by a conventionally known method. The resin film is preferably produced by extrusion molding, and the extrusion molding is more preferably carried out by a T-die method or an inflation method. Hereinafter, an example of a method for producing a resin film by the T-die method and the inflation method will be described.

[0061] In the T-die method, the resins constituting the resin film are dried, and then supplied to a melt extruder heated to a temperature above the melting point (Tm) to Tm+70°C, where they are melted and extruded into a sheet from the die of the T-die. The extruded sheet is then rapidly cooled and solidified on a rotating cooling drum or the like, thereby forming a resin film. As the melt extruder, a single screw extruder, a twin screw extruder, a vent extruder, a tandem extruder, etc. can be used depending on the purpose.

[0062] In the inflation method, the resins constituting the resin film are first dried and then fed into a melt extruder heated to a temperature above the melting point (Tm) to Tm + 70°C. The melted resin is then extruded into a cylindrical shape through an annular die. Air is then blown into the cylindrical molten resin from below to expand the diameter of the cylinder to a predetermined size, and cooling air is blown from below outside the cylinder. This expanded cylindrical body is called a bubble. The bubble is then folded into a film shape using guide plates and pinch rolls and wound up in a winding section. The folded film can be wound up as a cylinder, or both ends of the cylinder can be removed using a slitter or the like, separated into two films, and each can be wound up separately. This process allows the resin film to be formed. As the melt extruder, a single screw extruder, a twin screw extruder, a vent extruder, a tandem extruder, etc. can be used depending on the purpose.

[0063] Laminate Next, the laminate 20 of the present invention will be described. The laminate 20 includes at least one biaxially oriented plastic film and the above-mentioned resin film 10. By including the above-mentioned resin film 10, the laminate has an environmental load reducing property and can improve drop impact resistance, retort resistance, appearance, sealability, and functionality.

[0064] Fig. 2 is a cross-sectional view showing an example of a laminate 20 of the present invention. As shown in Fig. 2, the laminate 20 includes, in this order, a first biaxially oriented plastic film 21, a printed layer 22, a first adhesive layer 23, a second biaxially oriented plastic film 24, a second adhesive layer 25, and the resin film 10. The first biaxially oriented plastic film 21 forms an outer surface 20y of the laminate 20, and the resin film 10 forms an inner surface 20x.

[0065] Fig. 3 is a cross-sectional view showing another example of a laminate 20 of the present invention. As shown in Fig. 3, the laminate 20 includes, in this order, a first biaxially oriented plastic film 21, a printed layer 22, a first adhesive layer 23, a metal foil 26, a second adhesive layer 25, and the resin film 10. The first biaxially oriented plastic film 21 forms an outer surface 20y of the laminate 20, and the resin film 10 forms an inner surface 20x.

[0066] Fig. 4 is a cross-sectional view showing another example of a laminate 20 of the present invention. As shown in Fig. 4, the laminate 20 includes, in this order, a first biaxially oriented plastic film 21, a printed layer 22, a first adhesive layer 23, a second biaxially oriented plastic film 24, a second adhesive layer 25, a metal foil 26, a third adhesive layer 27, and the resin film 10. The first biaxially oriented plastic film 21 forms an outer surface 20y of the laminate 20, and the resin film 10 forms an inner surface 20x.

[0067] Fig. 5 is a cross-sectional view showing another example of a laminate 20 of the present invention. As shown in Fig. 5, the laminate 20 includes, in this order, a first biaxially oriented plastic film 21, a printed layer 22, a first adhesive layer 23, a metal foil 26, a second adhesive layer 25, a second biaxially oriented plastic film 24, a third adhesive layer 27, and the resin film 10. The first biaxially oriented plastic film 21 forms an outer surface 20y of the laminate 20, and the resin film 10 forms an inner surface 20x.

[0068] The first biaxially oriented plastic film 21, the second biaxially oriented plastic film 24, the printing layer 22, the metal foil 26, the first adhesive layer 23, the second adhesive layer 25 and the third adhesive layer 27 will each be described in detail below.

[0069] (First biaxially stretched plastic film and second biaxially stretched plastic film) Examples of resin materials that can be used to form the first biaxially oriented plastic film and the second biaxially oriented plastic film include polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), 1,4-polycyclohexylene dimethylene terephthalate, and terephthalic acid-cyclohexanedimethanol-ethylene glycol copolymer; polyamides such as nylon 6 and nylon 6,6; polyolefins such as polyethylene (PE), polypropylene (PP), and polymethylpentene; vinyl resins such as polyvinyl chloride, polyvinyl alcohol (PVA), polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, and polyvinylpyrrolidone (PVP); (meth)acrylic resins such as polyacrylate, polymethacrylate, and polymethyl methacrylate; cellulose resins such as cellophane, cellulose acetate, nitrocellulose, cellulose acetate propionate (CAP), and cellulose acetate butyrate (CAB); styrene resins such as polystyrene (PS), and chlorinated resins thereof. Among these, polyolefin, polyester and polyamide are preferred, and polypropylene, polyethylene terephthalate, nylon 6 and nylon 6,6 are more preferred. In the present invention, "(meth)acrylic" means to include both "acrylic" and "methacrylic", and "(meth)acrylate" means to include both "acrylate" and "methacrylate".

[0070] As long as the properties of the present invention are not impaired, the first biaxially oriented plastic film and the second biaxially oriented plastic film may contain additives such as fillers, plasticizers, antistatic agents, ultraviolet absorbers, inorganic particles, organic particles, release agents, and dispersants.

[0071] (Printing layer) The printing layer is a layer printed on the first biaxially oriented plastic film to display product information and add aesthetic appeal to the bag. The printing layer displays letters, numbers, symbols, figures, pictures, etc. Gravure printing inks and flexographic printing inks can be used as materials for the printing layer.

[0072] The ink that constitutes the printing layer contains a binder and a pigment. The binder, like the first adhesive layer, the second adhesive layer, and the third adhesive layer, contains, for example, polyurethane. Polyurethane is a cured product produced by reacting a polyol as the base resin with an isocyanate compound as the curing agent. Details of the polyol and isocyanate compound are described in the sections on the first adhesive layer, the second adhesive layer, and the third adhesive layer.

[0073] The pigment in the printing layer is a colored powder that exists in the binder at a predetermined distribution density. The color of the pigment is not particularly limited, and various pigments such as red, blue, green, white, and black can be used. For example, the average particle size of the pigment may be 0.1 μm or more and 1 μm or less, or 0.5 μm or more and 1 μm or less. Note that white pigments generally have larger dimensions than pigments of other colors. For example, the average particle size of white pigments is 0.5 μm or more and 1 μm or less. The average particle size of the pigment can be measured by dynamic light scattering.

[0074] The printing layer may consist of a single layer or may include multiple layers. For example, the printing layer may include a first layer containing a pigment that exhibits a first color and a second layer containing a pigment that exhibits a second color different from the first color. The thickness of one printing layer is, for example, 0.5 μm or more and 3 μm or less.

[0075] (metal foil) As the metal foil, a conventionally known metal foil can be used. Aluminum foil is preferred from the viewpoints of gas barrier properties that prevent the transmission of oxygen gas, water vapor, etc., and light blocking properties that prevent the transmission of visible light, ultraviolet light, etc. The thickness of the metal foil is, for example, 5 μm or more and 15 μm or less.

[0076] (First adhesive layer, second adhesive layer and third adhesive layer) The adhesive layers, such as the first adhesive layer, the second adhesive layer, and the third adhesive layer, contain an adhesive for bonding a first biaxially oriented plastic film, a second biaxially oriented plastic film, etc. to each other. The adhesive constituting the adhesive layers is produced from an adhesive composition prepared by mixing a first composition containing a base agent and a solvent with a second composition containing a curing agent and a solvent. Specifically, the adhesive contains a cured product produced by reaction of the base agent and the solvent in the adhesive composition.

[0077] Examples of adhesives include ether-based two-component reactive adhesives and ester-based two-component reactive adhesives. An example of an ether-based two-component reactive adhesive is polyether polyurethane. Polyether polyurethane is a cured product produced by reacting a polyether polyol as a base material with an isocyanate compound as a curing agent. Examples of ester-based two-component reactive adhesives include polyester polyurethane and polyester. Polyester polyurethane is a cured product produced by reacting a polyester polyol as a base material with an isocyanate compound as a curing agent.

[0078] Isocyanate compounds that react with polyols such as polyether polyols and polyester polyols to produce cured products include aromatic isocyanate compounds and aliphatic isocyanate compounds. Among these, aromatic isocyanate compounds leach out components that cannot be used in food applications under high-temperature conditions, such as during heat sterilization (retort processing). As shown in FIGS. 2 to 5, the adhesive layer contacts the resin film 10 that forms the inner surface 20x of the laminate 20. Therefore, if the adhesive layer contains an aromatic isocyanate compound, components leach out from the aromatic isocyanate compound may adhere to the contents of the bag 30 formed from the laminate 20.

[0079] In consideration of these issues, the adhesive layer is made of a cured product produced by the reaction of a polyol as the base agent with an aliphatic isocyanate compound as the curing agent. This prevents the adhesive layer from contaminating the contents with ingredients that are unsuitable for food applications. Examples of aliphatic isocyanates include hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI).

[0080] Furthermore, drop impact resistance can be improved by increasing the molar ratio of the isocyanate groups of the aliphatic isocyanate compound to the hydroxy groups of the polyol. For example, the molar ratio of the curing agent (aliphatic isocyanate compound) to the hydroxy groups of the base agent (polyol) has conventionally been about 3. In this embodiment, the molar ratio of the isocyanate groups of the aliphatic isocyanate compound to the hydroxy groups of the polyol is preferably 3.5 or more, more preferably 4 or more, and even more preferably 4.5 or more. More preferably, the molar ratio of the isocyanate groups of the aliphatic isocyanate compound to the hydroxy groups of the polyol is greater than 5.

[0081] On the other hand, aliphatic isocyanate compounds are expensive, and increasing the amount of aliphatic isocyanate compounds is undesirable in terms of production costs. Furthermore, the higher the molar ratio of isocyanate groups in the aliphatic isocyanate compound to hydroxy groups in the polyol, the higher the temperature or the longer the time required to cure the adhesive composition. Taking these points into consideration, the molar ratio of aliphatic isocyanate groups to hydroxy groups is preferably 7 or less, and more preferably 6 or less.

[0082] The adhesive layer is formed by applying an adhesive composition to a first biaxially oriented plastic film, a second biaxially oriented plastic film, a metal foil, or a resin film, and then drying the adhesive composition and curing the adhesive composition through a reaction between the main agent and the solvent in the adhesive composition. In this embodiment, the weight per unit area of ​​the adhesive composition after drying is, for example, 2 g / m 2 More than 5g / m 2 It is preferable that the density is 3 g / m or less. 2 More than 4g / m 2 The thickness of the adhesive layer 60 is preferably 2 μm or more and 5 μm or less, and more preferably 3 μm or more and 4 μm or less.

[0083] (Specific examples of layer structure of laminate) Specific examples of the laminate 20 shown in Figures 2 to 5 are shown below. Note that " / " indicates the boundary between layers. The leftmost layer is the layer that forms the outer surface 20y of the laminate 20, and the rightmost layer is the layer that forms the inner surface 20x of the laminate 20. Also, "biaxially oriented PET film" means a biaxially oriented polyethylene terephthalate film. (1) Biaxially oriented PET film / printing layer / adhesive layer / biaxially oriented nylon film / adhesive layer / resin film (2) Biaxially oriented PET film / printing layer / adhesive layer / metal foil / adhesive layer / resin film (3) Biaxially oriented PET film / printing layer / adhesive layer / biaxially oriented nylon film / adhesive layer / metal foil / adhesive layer / resin film (4) Biaxially oriented PET film / printing layer / adhesive layer / metal foil / adhesive layer / biaxially oriented nylon film / adhesive layer / resin film (5) Biaxially oriented PET film / printing layer / adhesive layer / biaxially oriented PET film / adhesive layer / metal foil / adhesive layer / resin film (6) Biaxially oriented PET film / printing layer / adhesive layer / metal foil / adhesive layer / biaxially oriented PET film / adhesive layer / resin film

[0084] (Method of manufacturing laminate) The method for producing the laminate is not particularly limited, and it can be produced by a conventionally known method such as dry lamination, melt extrusion lamination, or sand lamination.

[0085] bag Next, the bag 30 of the present invention will be described. Fig. 6 is a front view showing the bag 30 according to this embodiment. Fig. 7 is an exploded view showing the film constituting the bag shown in Fig. 6. The bag 30 has a storage section 30a that stores contents. The bag 30 according to this embodiment is configured so that it can be subjected to retort treatment. Therefore, the bag of the present invention is preferably a bag that can be subjected to retort treatment, such as a retort pouch. The configuration of the bag 30 will be described below.

[0086] In this embodiment, bag 30 is a gusset-type bag configured to be self-standing. Bag 30 includes an upper portion 31, a lower portion 32, and a side portion 33, and has a generally rectangular outline in a front view. Note that the names "upper portion," "lower portion," and "side portion," as well as terms such as "above" and "below," merely describe the relative positions and directions of bag 30 and its components, based on a state in which bag 30 is self-standing with the gusset portion facing downwards. The names and terms used in this specification do not limit the position, etc., of bag 30 during transportation or use.

[0087] 6 and 7, bag 30 includes a surface film 34 that forms the surface, a back film 35 that forms the back surface, and a lower film 36 that forms lower portion 32. Lower film 36 is folded in half at fold-over portion 36f and is disposed between surface film 34 and back film 35. Surface film 34, back film 35, and lower film 36 are each composed of laminate 20 described above.

[0088] The lower film 36 also has semicircular notches 36a near the lower ends of both edges. Because the lower film 36 is folded in half, the notches 36a are provided so as to penetrate the overlapping portions of the lower film 36. By providing such notches 36a, the front film 34 and the back film 35 can be directly heat-sealed at the lower seal portion 32a, as described below. In Figures 6 and 7, the shape of the notches 36a is semicircular, but the shape is not limited thereto. For example, the notches 36a may be polygonal, such as triangular or rectangular.

[0089] The terms "surface film," "back film," and "lower film" mentioned above merely distinguish each film according to its positional relationship, and the terms do not limit the method of providing the films when manufacturing bag 30. For example, bag 30 may be manufactured using one film in which surface film 34, back film 35, and lower film 36 are connected together, or may be manufactured using two films: one film in which surface film 34 and lower film 36 are connected together and one back film 35, or may be manufactured using three films: one surface film 34, one back film 35, and one lower film 36.

[0090] The inner surfaces of the front film 34, back film 35 and bottom film 36 are joined together by sealed portions. In the front view of bag 30 shown in Figure 6, the sealed portions are hatched.

[0091] As shown in Figure 6, the seal portion has an outer edge seal portion that extends along the outer edge of the bag 30. The outer edge seal portion includes an upper seal portion 31a that extends along the upper portion 31, a lower seal portion 32a that extends to the lower portion 32, and a pair of side seal portions 33a that extend along a pair of side portions 33. Before the contents are filled into the bag 30 (when the contents are not filled), an opening (not shown) is formed in the upper portion 31 of the bag 30. After the contents are placed in the bag 30, the inner surfaces of the front film 34 and the back film 35 are joined at the upper portion 31 to form the upper seal portion 31a and seal the bag 30.

[0092] Top seal portion 31a and side seal portion 33a are seal portions formed by joining the inner surface of top film 34 and the inner surface of back film 35. Meanwhile, bottom seal portion 32a includes a seal portion formed by joining the inner surface of top film 34 and the inner surface of bottom film 36, and a seal portion formed by joining the inner surface of back film 35 and the inner surface of bottom film 36. Note that the inner surfaces of top film 34 and the inner surface of back film 35 are joined within notch 36a of bottom film 36. This allows bag 30 to stand upright stably without hindering the expansion of bottom film 36 when filling the contents.

[0093] There are no particular limitations on the method for forming the seal portion, as long as it is possible to join opposing films together and seal bag 30. For example, the seal portion may be formed by melting the inner surfaces of the films by heating or the like and fusing the inner surfaces together, i.e., by heat sealing.

[0094] (Easy-to-open means) The front film 34 and the back film 35 may be provided with easy-open means 37 for tearing the front film 34 and the back film 35 to open the bag 30. For example, as shown in Fig. 6, the easy-open means 37 may include a notch 38 formed in the side seal portion 33a of the bag 30, which serves as a tearing starting point. Alternatively, the easy-open means 37 may be a half-cut line formed by laser processing, a cutter, or the like, in a portion that serves as a path for tearing the bag 30.

[0095] Furthermore, although not shown, the easy-open means 37 may include a group of cuts or scars formed in the area where the seal portion is formed of the front film 34 and the back film 35. The group of scars may include, for example, a plurality of through holes formed so as to penetrate the front film 34 and / or the back film 35. Alternatively, the group of scars may include a plurality of holes formed on the outer surface of the front film 34 and / or the back film 35 so as not to penetrate the front film 34 and / or the back film 35.

[0096] (Bag manufacturing method) First, a surface film 34 and a back film 35 made of the laminate 20 described above are prepared. A folded-over bottom film 36 is inserted between the surface film 34 and the back film 35. The inner surfaces of the films are then heat-sealed to form seals, such as bottom seal 32a and side seal 33a. The films joined together by heat sealing are then cut into an appropriate shape to obtain the bag 30 shown in FIG. 6. Contents are then filled into the bag 30 through an opening (not shown) in the top 31. The contents are, for example, cooked food containing moisture, such as curry, stew, or soup. The top 31 is then heat-sealed to form top seal 31a. In this manner, a bag 30 containing and sealed with the contents can be obtained. [Example]

[0097] Next, the present invention will be explained in more detail with reference to examples. However, the present invention is not limited to the following examples as long as it does not depart from the gist of the present invention.

[0098] [Example 1] The resin film 10 was made of a mixture of 65 mass % of a propylene-ethylene block copolymer (manufactured by Prime Polymer Co., Ltd., product name: J715M, biomass content: 0%), 10 mass % of a styrene-ethylene / butylene-styrene block copolymer (SEBS) (manufactured by Mitsui Chemicals, Inc., product name: Tafmer A0585), and a biomass linear low-density polyethylene (manufactured by Braskem, product name: SLL-118, density: 916 kg / m3 A resin composition containing 25% by mass of cellulose acetate (biomass content: 87%) was extruded through a T-die to produce an unstretched resin film with a thickness of 60 μm. The biomass content of the resin film was 21.8%.

[0099] Next, a 12 μm thick biaxially oriented polyethylene terephthalate film (manufactured by Toyobo Co., Ltd., product name: E5100) was prepared as the first biaxially oriented plastic film 21. Subsequently, a printed layer 22 was formed on this first biaxially oriented plastic film 21. The thickness of the printed layer 22 was 1.0 μm. Furthermore, a 15 μm thick biaxially oriented nylon film (manufactured by Kohjin Film & Chemicals Co., Ltd., product name: Bonyl-QC) was prepared as the second biaxially oriented plastic film 24.

[0100] Next, a first biaxially oriented plastic film 21, a printed layer 22, a first adhesive layer 23, a second biaxially oriented plastic film 24, a second adhesive layer 25, and a resin film 10 were laminated in this order by dry lamination to produce the laminate 20 shown in FIG. 2. A two-component polyurethane adhesive (main agent: RU-40, curing agent: H-4) manufactured by Rock Paint Co., Ltd. was used for the first adhesive layer 23 and the second adhesive layer 25. The main agent, RU-40, is a polyester polyol. The thickness of the first adhesive layer 23 and the second adhesive layer 25 was 3.0 μm each.

[0101] Next, a bag (standing bag) as shown in Fig. 6 was produced. Specifically, first, a surface film 34, a back film 35, and a lower film 36 were produced from the obtained laminate 20. In this case, the lower film 36 was folded in half so that the first biaxially oriented plastic film 21 was on the inside, and while in this folded state, circles with a diameter of 10 mm were punched out at locations near the lower ends of both edges of the lower film 36 when it was cut into bag 30, to form through-holes.

[0102] Next, the surface film 34 and the back surface film 35 were overlapped so that the resin film 10 of the surface film 34 and the resin film 10 of the back surface film 35 were in contact with each other. Then, the folded lower film 36 was placed between the surface film 34 and the back surface film 35 so that the resin film 10 of the surface film 34 and the resin film 10 of the lower film 36 were in contact with each other and so that the resin film 10 of the back surface film 35 and the resin film 10 of the lower film 36 were in contact with each other.

[0103] Then, bottom sealed portion 32a and side sealed portion 33a were formed by heat sealing to fit the shape of each bag 30. Heat sealing was performed under the following conditions. (Heat sealing conditions) Heat sealing device: Heat sealer (Tester Sangyo Co., Ltd., product name: TP-701-A) Heat sealing temperature: 220℃ Heat sealing pressure: 0.1MPa Heat sealing time: 1 second

[0104] Next, the heat-sealed area was cut to fit the shape of each bag 30, thereby producing the bags 30 shown in FIG.

[0105] Next, 200 g of water was filled as the content through an opening (not shown) in the top 31 of the prepared bag 30, and the top of the front film 34 and the top of the back film 35 were heat-sealed under the same conditions as the heat-sealing conditions described above, thereby sealing the bag 30. In this manner, the bag 30 was prepared. In addition, a bag 30 filled with 180 g of curry as the content and a bag 30 filled with no content were also prepared.

[0106] The produced bag 30 had a height S1 (see Figure 6) of 160 mm, a width S2 of 147 mm, a width S3 of the upper seal portion 31a of 10.0 mm, a width S4 of the side seal portion 33a of 7.0 mm, and a height S5 of the folded lower film 36 of 46 mm.

[0107] [Example 2] The mixture consisted of 60% by mass of propylene-ethylene block copolymer (Prime Polymer Co., Ltd., product name: J715M, biomass content: 0%), 10% by mass of styrene-ethylene / butylene-styrene block copolymer (SEBS) (Mitsui Chemicals, Inc., product name: Tafmer A0585), and biomass linear low-density polyethylene (Braskem, product name: SLL-118, density: 916 kg / m). 3 A resin film was produced in the same manner as in Example 1, except that a resin composition containing 30 mass% of cellulose acetate (biomass fiber, biomass content: 87%) and 30 mass% of cellulose acetate (biomass fiber, biomass content: 87%) was used. The thickness of the resin film was 60 μm, and the biomass content of the resin film was 25.2%. Furthermore, a laminate and a bag were produced in the same manner as in Example 1 using the obtained resin film.

[0108] [Example 3] The mixture consisted of 75% by mass of propylene-ethylene block copolymer (Prime Polymer Co., Ltd., product name: J715M, biomass content: 0%), 10% by mass of styrene-ethylene / butylene-styrene block copolymer (SEBS) (Mitsui Chemicals, Inc., product name: Tafmer A0585), and biomass linear low-density polyethylene (Braskem, product name: SLL-118, density: 916 kg / m). 3 A resin film was produced in the same manner as in Example 1, except that a resin composition containing 15% by mass of cellulose acetate (biomass fiber, biomass content: 87%) and 15% by mass of cellulose acetate was used. The thickness of the resin film was 60 μm, and the biomass content of the resin film was 12.6%. Furthermore, a laminate and a bag were produced in the same manner as in Example 1 using the obtained resin film.

[0109] [Example 4] The mixture consisted of 60% by mass of propylene-ethylene block copolymer (Prime Polymer Co., Ltd., product name: J715M, biomass content: 0%), 10% by mass of styrene-ethylene / butylene-styrene block copolymer (SEBS) (Mitsui Chemicals, Inc., product name: Tafmer A0585), and biomass linear low-density polyethylene (Braskem, product name: SLL-118, density: 916 kg / m). 325% by mass (biomass content: 87%) and fossil fuel linear low-density polyethylene (Prime Polymer Co., Ltd., product name: SP2040, density: 918 kg / m 3 A resin film was produced in the same manner as in Example 1, except that a resin composition containing 5% by mass of cellulose acetate (biomass fraction: 0%) was used. The thickness of the resin film was 60 μm, and the biomass fraction of the resin film was 21.8%. Furthermore, a laminate and a bag were produced in the same manner as in Example 1 using the obtained resin film.

[0110] [Comparative Example 1] The polymer consisted of 60% by mass of a propylene-ethylene block copolymer (Prime Polymer Co., Ltd., product name: J715M, biomass content: 0%) and 60% by mass of a biomass linear low-density polyethylene (Braskem, product name: SLL-118, density: 916 kg / m 3 A resin film was produced in the same manner as in Example 1, except that a resin composition containing 40 mass% of cellulose acetate (biomass fraction: 87%) and 40 mass% of cellulose acetate was used. The thickness of the resin film was 60 μm, and the biomass fraction of the resin film was 33.6%. Furthermore, a laminate and a bag were produced in the same manner as in Example 1 using the obtained resin film.

[0111] Comparative Example 2 The mixture consisted of 65% by mass of propylene-ethylene block copolymer (Prime Polymer Co., Ltd., product name: J715M, biomass content: 0%), 10% by mass of styrene-ethylene / butylene-styrene block copolymer (SEBS) (Mitsui Chemicals, Inc., product name: Tafmer A0585), and biomass high-pressure low-density polyethylene (Braskem, product name: SEB-853, density: 923 kg / m). 3 A resin film was produced in the same manner as in Example 1, except that a resin composition containing 25 mass% of cellulose acetate (biomass fraction: 87%) and 25 mass% of cellulose acetate (biomass fraction: 87%) was used. The thickness of the resin film was 60 μm, and the biomass fraction of the resin film was 24.3%. Furthermore, a laminate and a bag were produced in the same manner as in Example 1 using the obtained resin film.

[0112] Comparative Example 3 The composite consisted of 70% by mass of propylene-ethylene random copolymer (Prime Polymer Co., Ltd., product name: F219DA, biomass content: 0%), 10% by mass of styrene-ethylene / butylene-styrene block copolymer (SEBS) (Mitsui Chemicals, Inc., product name: Tafmer A0585), and biomass linear low-density polyethylene (Braskem, product name: SLL-118, density: 916 kg / m). 3 A resin film was produced in the same manner as in Example 1, except that a resin composition containing 20 mass% of cellulose acetate (biomass fraction: 87%) and 20 mass% of cellulose acetate (biomass fraction: 87%) was used. The thickness of the resin film was 60 μm, and the biomass fraction of the resin film was 16.8%. Furthermore, a laminate and a bag were produced in the same manner as in Example 1 using the obtained resin film.

[0113] Comparative Example 4 The composite consisted of 60% by mass of propylene-ethylene block copolymer (Prime Polymer Co., Ltd., product name: J715M, biomass content: 0%) and fossil fuel-derived linear low-density polyethylene (Prime Polymer Co., Ltd., product name: SP2040, density: 918 kg / m 3 A resin film was produced in the same manner as in Example 1, except that a resin composition containing 40% by mass of cellulose acetate (biomass content: 0%) and 40% by mass of cellulose acetate (biomass content: 0%) was used. The thickness of the resin film was 60 μm, and the biomass content of the resin film was 0%. Furthermore, a laminate and a bag were produced in the same manner as in Example 1 using the obtained resin film.

[0114] The compositions of the resin compositions constituting the resin films according to Examples 1 to 4 and Comparative Examples 1 to 4 are shown in Table 1. In Table 1, "petroleum-based block PP" means a propylene-ethylene block copolymer, "petroleum-based random PP" means a propylene-ethylene random copolymer, "bio-LLDPE" means biomass linear low-density polyethylene, "petroleum-based LLDPE" means fossil fuel linear low-density polyethylene, "bio-LDPE" means biomass high-pressure low-density polyethylene, and "SEBS" means a styrene-ethylene / butylene-styrene block copolymer. Note that all "%" in Table 1 is based on mass.

[0115] [Table 1]

[0116] <<Drop impact resistance evaluation>> Drop impact resistance evaluation was performed using bags 30 according to Examples 1 to 4 and Comparative Examples 1 to 4 filled with 200 g of water. The drop impact resistance evaluation was performed by conducting a drop test in which the bag 30 was dropped in a room temperature (approximately 25°C) environment and inspected to see if the bag 30 broke. Specifically, the bag 30 was held with the lower part 32 positioned downwards and dropped from a height of 120 cm, and this test was repeated 10 times. This drop test was performed on 10 bags 30. The evaluation results are shown in Table 2. Note that in the drop impact resistance evaluation column in Table 1, the denominator is the number of bags that were subjected to the drop test, and the numerator is the number of bags that did not break in the drop test.

[0117] <<Retort resistance evaluation>> Retort resistance evaluation was performed using bags 30 according to Examples 1 to 4 and Comparative Examples 1 to 4 filled with 200 g of water. The retort treatment was performed using a spray method, and the temperature, pressure, and time of the retort treatment were set at two conditions: 135°C, 0.3 MPa, 30 minutes, and 121°C, 0.2 MPa, 30 minutes. After each retort treatment, the bags were checked for the presence or absence of wrinkles. The evaluation results are shown in Table 2. (Evaluation criteria) Good: No wrinkles were observed in the bags after treatment at 135°C and 121°C. Acceptable: Wrinkles occurred in the bag after treatment at 135°C, but no wrinkles occurred in the bag after treatment at 120°C. · Unacceptable: Wrinkles appeared on the bag after both the 135℃ and 121℃ treatments.

[0118] <<Appearance evaluation>> Appearance evaluation was carried out using bags 30 according to Examples 1 to 4 and Comparative Examples 1 to 4 filled with 180. The appearance evaluation was carried out by retorting the bags 30 at 135°C for 30 minutes and visually checking for whitening of the bags 30 and the occurrence of unevenness on the surface of the bags 30 (yellow-orange peeling). The evaluation results are summarized in Table 1. (Evaluation results) Good: No whitening or orange peeling of the surface was observed. · Unacceptable: Whitening or orange peeling of the surface was observed.

[0119] <<Sealability test>> A sealability test was conducted using bags 30 according to Examples 1 to 4 and Comparative Examples 1 to 4 that were not filled with contents. The sealability test was conducted by measuring the seal strength of the sealed portion of bag 30. The seal strength was measured in accordance with JIS K 7127:1999 at a temperature of 25°C and a relative humidity of 50%, using a tensile tester, model SA-1150, manufactured by Orientec Co., Ltd. Specifically, as shown in FIG. 8, a rectangular test piece 40 was cut out, including side seal portion 33a, with one side S6 measuring 15 mm and the other side S7 extending perpendicular to the first side being 50 mm. Next, as shown in FIG. 9, the unsealed portion of front film 34 and the unsealed portion of back film 35 of test piece 40 were oriented in opposite directions perpendicular to the surface direction of the sealed portion, i.e., formed into a T-shape, and the ends of the unsealed portion of front film 34 and the unsealed portion of back film 35 were fixed to grippers 41 and 42, respectively. The chuck distance (S8) was set to 50 mm, and each of the gripping devices 41 and 42 was pulled in opposite directions perpendicular to the surface direction of the seal portion of the test piece 40 at a speed of 300 mm / min, and the maximum tensile stress was measured. This maximum tensile stress value was taken as the seal strength. The evaluation results are shown in Table 2. (Evaluation criteria) Good: The seal strength was 30N / 15mm or more. · Unacceptable: The seal strength was less than 30N / 15mm.

[0120] <<Sensory test>> A sensory test was conducted using bags 30 according to Examples 1 to 4 and Comparative Examples 1 to 4 filled with 200 g of water. The bags 30 were stored in an oven at 80°C for three days, and the occurrence of odors in the water contained therein and any changes in flavor, such as changes in taste, were confirmed. The evaluation results are shown in Table 2. (Evaluation criteria) Good: No change in the flavor of the water was observed. - Unacceptable: A change in the flavor of the water contained in the container was confirmed.

[0121] [Table 2]

[0122] As is clear from Table 2, the resin film, laminate and bag of the present invention have the ability to reduce environmental impact, and are also excellent in drop impact resistance, retort resistance, appearance, sealability and functionality. [Explanation of symbols]

[0123] 10 Resin film 20 laminate 20x inner surface 20y external surface 21 First biaxially stretched plastic film 22 Printing layer 23 First adhesive layer 24 Second biaxially stretched plastic film 25 Second adhesive layer 26 Metal foil 27 Third adhesive layer 30 bags 30a Storage section 31 Upper 31a Upper seal part 32 Lower 32a Lower seal 33 Side 33a Side seal 34 Surface film 35 Back film 36 Lower film 36a notch 36f Folded section 37 Easy-to-open means 38 notches 40 test specimens 41,42 Gripping tool

Claims

1. A bag including a laminate, The laminate includes at least one biaxially oriented plastic film and a single-layer resin film, the resin material constituting the biaxially stretched plastic film is polybutylene terephthalate, the resin film contains, as main components, a propylene-ethylene block copolymer, a thermoplastic elastomer, and polyethylene having a density of 925 kg / m 3 or less; the polyethylene comprises linear low-density polyethylene; the polyethylene comprises biomass polyethylene; The biomass content of the resin film is 27% or less, a mass ratio of the polyethylene in the resin film is 15% by mass or more and 30% by mass or less; A bag having a height of 160 mm and a width of 147 mm.

2. The bag according to claim 1, wherein the resin film has a biomass content of 23% or less.

3. 3. The bag according to claim 1, wherein the resin film contains the propylene-ethylene block copolymer, the linear low-density polyethylene, and the thermoplastic elastomer in that order.

4. 4. The bag of claim 1, wherein the polyethylene comprises biomass linear low density polyethylene.

5. The bag according to claim 1 , wherein the resin film has a breaking elongation of 500% or more in one direction and in another direction perpendicular to the one direction.

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