Multilayer body, method for producing same, packaging material, and coating agent

Abstract

Disclosed is a multilayer body which sequentially has a base material 1, an adhesive layer, and a base material 2 in this order, and which additionally has a coating layer. The base material 1 and the base material 2 contain a polyolefin resin. The coating layer contains a resin (A) which has a glass transition point of 115°C or higher. When heat and pressure are applied to the multilayer body under the heating and pressurization conditions described below, the shrinkage ratio of the multilayer body expressed by (formula 1) is 30% by area or less. (Heating and pressurization conditions) Heating temperature: 145°C Pressurization: 2 kg / cm2 Heating and pressurization time: 1 second (Formula 1): Shrinkage ratio (% by area) = (1 – (area after heating and pressurization) / (area before heating and pressurization)) × 100

Description

Laminate and its manufacturing method, packaging material and coating agent

[0001] The present invention relates to a laminate having excellent heat resistance, bag-forming suitability, and adhesion, and a method for producing the same. The present invention also relates to a packaging material using the laminate, and a coating agent that can be suitably used to form the laminate.

[0002] Packaging bags for flexible packages are made by combining multiple types of plastic materials. Typically, biaxially oriented films such as polypropylene or polyester are used to provide the packaging bag with mechanical strength, and polyethylene, polypropylene, ethylene-vinyl acetate copolymer, etc. are used as heat-sealing materials for sealing the contents of the packaging bag. The selection of the above materials has traditionally been designed with emphasis on suitability for each process, such as packaging, transportation, storage, and opening of the contents. However, in recent years, with growing awareness of environmental issues, resource conservation and recyclability of various products have become increasingly important.

[0003] Patent Document 1 discloses a laminate having a substrate, an adhesive layer, and a sealant layer, in which the substrate and sealant layer are made of polyethylene from the viewpoint of mono-materialization, thereby improving recyclability.

[0004] In a bag-making process for producing packaging bags, a laminate is folded so that the sealant layers overlap each other, and then the laminate is sandwiched by applying pressure from the outer surface of the base layer with a high-temperature tool to perform heat sealing. The tool of the heat-sealing machine is heated to a high temperature, and the outer surface of the base layer that directly contacts the tool is exposed to high temperatures. Therefore, when a packaging bag is produced using the laminate described in Patent Document 1, the base layer is affected by heat, which can cause thermal shrinkage of the heat-sealed portion and / or a phenomenon in which the heat-sealed portion is cut off from the laminate (melting), resulting in insufficient bag-making suitability.

[0005] Patent Document 2 discloses a laminate including a coating layer, a substrate layer, and a sealant layer, in which the substrate layer and the sealant layer are made of polyethylene, and the coating layer further contains a heat-resistant resin. The invention described in Patent Document 2 is a laminate that aims to improve heat-sealability by forming a coating layer made of a resin with excellent heat resistance. However, the heat resistance and adhesion of the coating layer are insufficient, and the bag-making suitability is still insufficient.

[0006] JP 2020-55157 A International Publication No. 2022 / 230812

[0007] As described above, conventional laminates using polyolefin resins are insufficient in heat resistance, bag-making suitability, and adhesiveness, and improvements are desired.

[0008] Therefore, an object of the present invention is to provide a laminate that is excellent in heat resistance, suitability for bag making, and adhesiveness.

[0009] One embodiment of the present invention relates to a laminate having a substrate 1, an adhesive layer, and a substrate 2 in this order, and further having a coating layer, wherein the substrate 1 and the substrate 2 each contain a polyolefin resin, the coating layer contains a resin (A) having a glass transition point of 115°C or higher, and the laminate has a shrinkage ratio of 30 area % or less, as expressed by the following formula (1), when heated and pressed under the following heating and pressing conditions: (Heating and pressing conditions) Heating temperature: 145°C, pressure: 2 kg / cm ２ Heating and pressing time: 1 second (Formula 1) Shrinkage rate (area %)={1-(area after heating and pressing) / (area before heating and pressing)}×100

[0010] Another embodiment of the present invention relates to a laminate having a coating layer and a substrate 1, wherein the substrate 1 contains a polyethylene resin, the coating layer contains a resin (A) having a glass transition point of 115°C or higher, and the laminate has a shrinkage ratio of 30 area % or less, as expressed by the following formula (1), when heated and pressed under the following heating and pressing conditions: Heating temperature: 145°C, Pressure: 2 kg / cm ２Heating and pressing time: 1 second (Formula 1) Shrinkage rate (area %)={1-(area after heating and pressing) / (area before heating and pressing)}×100

[0011] Another embodiment of the present invention relates to a method for producing a laminate having a substrate 1, an adhesive layer, and a substrate 2 in this order, and further having a coating layer, the method comprising the steps of printing a coating agent containing a resin (A) having a glass transition point of 115°C or higher on one surface of the substrate 1 to form a coating layer, printing an adhesive on the other surface of the substrate 1 or on the coating layer to form an adhesive layer, and laminating the substrate 2 onto the adhesive layer, wherein the shrinkage rate of the laminate, expressed by the following formula (1), when heated and pressed under the following heating and pressing conditions is 30 area % or less. (Heating and pressing conditions) Heating temperature: 145°C, pressure: 2 kg / cm ２ Heating and pressing time: 1 second (Formula 1) Shrinkage rate (area %)={1-(area after heating and pressing) / (area before heating and pressing)}×100

[0012] Another embodiment of the present invention is a coating agent used to form the coating layer of a laminate having a substrate 1, an adhesive layer, and a substrate 2 in this order, and further having a coating layer, wherein the substrate 1 and the substrate 2 contain a polyolefin-based resin, the coating agent comprising a resin (A) having a glass transition point of 115°C or higher, and a solvent.

[0013] According to the present invention, it is possible to provide a laminate that is excellent in heat resistance, bag-making suitability, and adhesiveness.

[0014] Fig. 1 is a plan view illustrating a method for measuring the shrinkage rate of a laminate under heating and pressing, and shows the area before heating and pressing when a laminate cut into a size of 50 mm x 25 mm is heated and pressed in a range of 20 mm x 10 mm. Fig. 2 is a plan view illustrating a method for measuring the shrinkage rate of a laminate under heating and pressing, and shows the area after heating and pressing when a laminate cut into a size of 50 mm x 25 mm is heated and pressed in a range of 20 mm x 10 mm.

[0015] Hereinafter, embodiments of the present invention will be described in detail. However, the following explanation of the components is an example of an embodiment of the present invention, and the present invention is not limited to these contents as long as it does not deviate from the gist of the present invention.

[0016] <1> Laminate In one embodiment, the laminate has a substrate 1, an adhesive layer, and a substrate 2 in this order, and further has a coating layer, wherein the substrate 1 and the substrate 2 contain a polyolefin resin, and the laminate has a shrinkage percentage of 30 area % or less, as expressed by the following (Equation 1), when heated and pressed under the following heating and pressing conditions: (Heating and Pressing Conditions) Heating temperature: 145°C, Pressure: 2 kg / cm ２ , Heating and pressing time: 1 second (Formula 1) Shrinkage rate (area %)={1-(area after heating and pressing) / (area before heating and pressing)}×100 The shrinkage rate is preferably 30 area % or less, more preferably 15 area % or less, and even more preferably 5 area % or less.

[0017] In another embodiment, the laminate has a coating layer and a substrate 1, the substrate 1 containing a polyethylene resin, and when heated and pressurized under the following heating and pressurizing conditions, the laminate has a shrinkage percentage of 30 area % or less, as expressed by the following (Equation 1): (Heating and Pressurizing Conditions) Heating temperature: 145°C, Pressure: 2 kg / cm ２ , Heating and pressing time: 1 second (Formula 1) Shrinkage rate (area %)={1-(area after heating and pressing) / (area before heating and pressing)}×100 The shrinkage rate is preferably 30 area % or less, more preferably 15 area % or less, and even more preferably 5 area % or less.

[0018] By setting the shrinkage rate of the laminate within the above range, it is possible to obtain a laminate that is excellent in heat resistance to heating and pressure in a heat sealing process and the like, and that is excellent in bag-making suitability and adhesiveness.

[0019] <Configuration of Laminate> Specific examples of the configuration of the laminate include, but are not limited to, the following configurations. In the configurations (1) to (4) described below, " / " indicates the boundary between layers. (1) Coat layer / substrate 1 / adhesive layer / substrate 2 (2) Substrate 1 / coat layer / adhesive layer / substrate 2 (3) Substrate 1 / adhesive layer / coat layer / substrate 2 (4) Coat layer / substrate 1

[0020] In the laminate of this embodiment, the coating layer is preferably adjacent to the substrate 1, and is preferably located as the outermost layer of the laminate. When the laminate has this configuration, the coating layer suppresses shrinkage of the laminate, making it possible to provide a laminate with even better heat resistance and bag-making suitability. Furthermore, in a structure in which the substrate 1 and the substrate 2 are laminated via an adhesive layer, the coating layer is preferably adjacent to at least one of the substrate 1 and the substrate 2. The coating layer is preferably adjacent to the substrate 1, and more preferably provided on one side of the substrate 1 and constituting the outermost surface of the laminate.

[0021] Films of polyolefin resins such as polyethylene and polypropylene (hereinafter also referred to as polyolefin films or polyolefin substrates) can be suitably used as the substrate 1 and the substrate 2. The substrate 1 and the substrate 2 may be made of the same material or different materials, but from the viewpoint of recyclability, they are preferably made of the same material. Among the embodiments that satisfy the shrinkage rate requirements of the laminate described above, the following are preferred examples of laminate configurations: Coat layer / polyethylene film / adhesive layer / polyethylene film Coat layer / polypropylene film / adhesive layer / polypropylene film Coat layer / polyethylene film Coat layer / polypropylene film Polyethylene film / coat layer / adhesive layer / polyethylene film Polypropylene film / coat layer / adhesive layer / polypropylene film Of the above laminate configurations, a configuration in which the coat layer is the outermost layer is particularly preferred from the viewpoint of shrinkage suppression.

[0022] Furthermore, from the viewpoint of recyclability, it is preferable that the color change (color change) of the laminate due to heating is small. In some embodiments, when the laminate is heated at 200°C, the color change ΔE of the laminate before and after heating is preferably 30 or less, more preferably 20 or less, and even more preferably 10 or less. The coating layer makes it easy to adjust the color change of the laminate before and after heating to within the above range, thereby easily improving the recyclability of the film. The color change ΔE can be measured according to a method known in the art. For example, the method described in the Examples below can be applied.

[0023] In an embodiment that satisfies the shrinkage rate requirements of the laminate described above, the coating layer may be primarily composed of a binder resin (hereinafter referred to as "resin") and / or particles. "Main component" means that the resin is present in an amount of 50% by mass or more relative to the total mass of the coating layer. In some embodiments, the coating layer preferably contains at least a resin, preferably a resin and particles, and more preferably a resin and inorganic particles. The resin contained in the coating layer may be a film-forming resin known as a binder resin, but preferably contains a resin (A) having a glass transition point of 115°C or higher. It is more preferable that the resin (A) has a glass transition point of 120°C or higher.

[0024] In some embodiments, the resin (A) preferably contains a resin having a ring structure, such as a cellulose-based resin, and more preferably contains at least one selected from the group consisting of nitrocellulose, cellulose acetate, cellulose acetate propionate, and cellulose acetate butyrate. In some embodiments, the coating layer preferably further contains particles. The particles are not particularly limited, but preferably contain at least one selected from the group consisting of silica, calcium carbonate, barium sulfate, titanium oxide, and zinc oxide, and more preferably contain barium sulfate. In the above-mentioned embodiments, the coating layer has excellent adhesion to the polyolefin substrate, exhibits little flow of the coating film when heated, and can significantly suppress thermal shrinkage of the polyolefin substrate. Therefore, it is easy to satisfy the shrinkage ratio represented by the above formula (1).

[0025] As a particularly preferred embodiment that satisfies the shrinkage rate requirements of the laminate described above, it is preferable that the laminate has the structure (1) or (4) exemplified above, and the coating layer contains a resin and inorganic particles. It is more preferable that the laminate has the structure (1) or (4) above, and the coating layer contains a resin (A) having a glass transition temperature of 120°C or higher, and inorganic particles. It is even more preferable that the laminate has the structure (1) or (4) above, and the coating layer contains a resin having a ring structure and inorganic particles. It is particularly preferable that the laminate has the structure (1) or (4) above, and the coating layer contains a cellulose-based resin and at least one selected from the group consisting of silica, calcium carbonate, barium sulfate, titanium oxide, and zinc oxide.

[0026] <Peak Temperature of Loss Tangent> With respect to the peak temperature of loss tangent (tan δ) measured according to JIS K 7244 between 80°C and 200°C, the laminate of this embodiment preferably has a difference of 1.0°C or more between the peak temperature of loss tangent (tan δ) of the laminate and the peak temperature of tan δ of the laminate excluding the coating layer, as shown in the following (Equation 2). In order to satisfy the peak temperature difference of tan δ, the same embodiment as the shrinkage percentage described above is preferred. When the difference in peak tan δ between the laminate and the laminate excluding the coating layer is within the above range, the coating layer does not flow when heated, thereby reducing the shrinkage percentage represented by the above equation (1), and the laminate has excellent heat resistance and bag-forming suitability. (Equation 2) Difference in Peak Temperature of Tan δ = (Peak Temperature of Tan δ of Laminate with Coating Layer) - (Peak Temperature of Tan δ of Laminate excluding the Coating Layer)

[0027] The coating layer adheres to the polyolefin substrate, and the coating film flows little when heated, so the shrinkage rate of the laminate can be reduced. Due to the above effects, the laminate of this embodiment is believed to achieve high levels of improvement in heat resistance, bag-making suitability, adhesion, and blocking resistance. Note that this explanation is based solely on technical considerations and does not limit the invention in any way.

[0028] <Coating Layer> The coating layer can be formed by printing a coating agent and removing the volatile components. In some embodiments, the laminate of this embodiment can be easily constructed using the coating agent described below. The coating layer is preferably a heat-resistant coating layer, which adheres closely to the polyolefin substrate, reduces the flow of the coating film when heated, and can suppress thermal shrinkage of the polyolefin substrate. Therefore, the shrinkage rate represented by the above formula (1) can be reduced, and the laminate can be provided with heat resistance and bag-making suitability.

[0029] The thickness of the coating layer is preferably 0.3 to 5 μm, more preferably 0.5 to 3 μm, and even more preferably 0.5 to 2 μm. When the thickness of the coating layer is within the above range, the heat resistance and suitability for bag making are good.

[0030] In some embodiments, the resin constituting the coating layer preferably includes a resin (A) having a glass transition point of 115°C or higher. The glass transition point of the resin (A) may be 120°C or higher, 130°C or higher, or 140°C or higher. The glass transition point of the resin (A) may be 220°C or lower, 210°C or lower, or 200°C or lower. In some embodiments, the glass transition point of the resin (A) is more preferably 120°C to 220°C, even more preferably 130°C to 210°C, and particularly preferably 140°C to 200°C.

[0031] When the glass transition point of the resin constituting the coating layer is 115° C. or higher, more preferably 120° C. or higher, excellent heat resistance is exhibited, the shrinkage percentage represented by the above formula (1) is reduced, and the heat resistance of the laminate when heated and the suitability for bag formation tend to be easily improved. Furthermore, when the glass transition point of the resin constituting the coating layer is 220° C. or lower, the coating layer tends to adhere more easily to the substrate, and the adhesion and heat resistance of the laminate tend to be easily improved.

[0032] <Coating Agent> One embodiment of the present invention relates to a coating agent comprising a binder resin containing a resin (A) having a glass transition point of 115°C or higher, and a solvent. The coating agent preferably further comprises particles. The coating agent of this embodiment can be suitably used to form the laminate, and more suitably used to form a coating layer of the laminate. The composition of the coating agent will be described below.

[0033] [Resin (A)] The coating agent contains, as a binder resin, resin (A) having a glass transition point of 115°C or higher. The glass transition point of resin (A) is preferably 120°C to 250°C, more preferably 120°C to 220°C, even more preferably 130°C to 210°C, and particularly preferably 140°C to 200°C. By containing resin (A) having a glass transition point of 115°C or higher, more preferably 120°C or higher, the coating layer exhibits excellent heat resistance, reduces the shrinkage factor represented by the above formula (1), and improves the heat resistance and bag-making suitability of the laminate when heated. Furthermore, by having resin (A) having a glass transition point of 250°C or lower, the coating layer adheres closely to the substrate, thereby improving the adhesion and heat resistance of the laminate.

[0034] In this specification, the glass transition point (glass transition temperature) is a value measured by DSC (differential scanning calorimetry). Resin (A) having a glass transition point of 115°C or higher may be one type of resin or a combination of two or more types of resins. In the case of a resin that does not have a glass transition point, any resin having a softening point or melting point of 115°C or higher is sufficient, and in this specification, such resins are also included in resin (A) having a glass transition point of 115°C or higher. When resin (A) is a combination of two or more types, the glass transition point of resin (A) is a weighted average value calculated based on the blending ratio of those two or more resins. That is, the glass transition point of resin (A) is preferably 115°C or higher, more preferably 120°C to 250°C, even more preferably 120°C to 220°C, particularly preferably 130°C to 210°C, and most preferably 140°C to 200°C.

[0035] The content of resin (A) is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70 to 95% by mass, based on the mass of the total solid content in the coating agent (100% by mass of the coating layer). When the content of resin (A) is within the above range, the heat resistance and bag-making suitability of the laminate are good.

[0036] The mass average molecular weight (Mw) of the resin (A) is preferably 13,000 to 70,000. The mass average molecular weight is more preferably 13,000 to 50,000, and even more preferably 13,000 to 40,000. When the mass average molecular weight of the resin (A) is 13,000 or more, excellent heat resistance is exhibited, resulting in good heat resistance and bag-making suitability of the laminate. On the other hand, when the mass average molecular weight of the resin (A) is 70,000 or less, the solid content of the coating agent can be increased, thereby allowing the film thickness of the heat-resistant coating layer to be within an appropriate range, improving the bag-making suitability of the laminate. The mass average molecular weight is measured by gel permeation chromatography (GPC). When the resin (A) contains two or more resins, the mass average molecular weight of the resin (A) is a weighted average calculated based on the blending ratio of the two or more resins (A).

[0037] Preferred examples of the resin (A) include urethane resins, acrylic resins, epoxy resins, polyolefin resins, polyester resins, polyamide resins, polyimide resins, polyamideimide resins, cellulose-based resins, and composite resins obtained by combining these resins. Among these, resins having a ring structure, such as cellulose-based resins, are preferred. The resin (A) may contain one or more of these resins. In particular, in some embodiments, from the viewpoint of heat resistance and adhesion, the resin (A) preferably contains a resin having a ring structure. In some embodiments, the resin (A) is preferably a resin having one or more ring structures, more preferably a cellulose-based resin. In some embodiments, from the viewpoint of heat resistance and adhesion, the resin (A) is preferably a combination of a resin having a ring structure and a polyamide resin, more preferably a combination of a cellulose-based resin and a polyamide resin. By using the resin (A), both heat resistance and substrate adhesion can be achieved, and the thermal shrinkage ratio of Formula 1 can be easily satisfied.

[0038] (Resin Having a Ring Structure) The resin having a ring structure may be a resin having an aromatic hydrocarbon structure such as a pyranose ring or a benzene ring, or an alicyclic hydrocarbon structure such as a cyclohexanone. The presence of the ring structure tends to improve heat resistance. Examples of resins having a ring structure include cellulose-based resins, polyimide resins, and polyamide-imide resins. Furthermore, among the resins listed above as examples of resin (A), copolymers of the resins with a monomer having a ring structure, such as an aromatic hydrocarbon monomer or an alicyclic hydrocarbon monomer, may also be used. Of these, cellulose-based resins are preferred as resins having a ring structure from the viewpoint of heat resistance. Specific examples of monomers having a ring structure include, but are not limited to, styrene, α-methylstyrene, β-methylstyrene benzyl acrylate, cyclohexyl acrylate, cyclobutanediol, cyclopentanediol, 1,4-cyclohexanediol, cycloheptanediol, 1,5-cyclooctanediol, and 1,4-cyclohexanedimethanol.

[0039] (Cellulose-based resin) Examples of cellulose-based resins include nitrocellulose, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, methylcellulose, ethylcellulose, hydroxypropylcellulose, hydroxyethylcellulose, and carboxymethylcellulose. In some embodiments, the resin is preferably one or more selected from the group consisting of nitrocellulose, cellulose acetate, cellulose acetate propionate, and cellulose acetate butyrate, and more preferably one or more selected from the group consisting of nitrocellulose, cellulose acetate propionate, and cellulose acetate butyrate. These cellulose-based resins may be used alone or in combination of two or more.

[0040] The content of the resin having a ring structure is preferably 30% by mass or more, more preferably 40% by mass or more, even more preferably 50% by mass or more, particularly preferably 60% by mass or more, and most preferably 70 to 95% by mass, based on the mass of the total solid content in the coating agent (100% by mass of the coating layer). When the content of the resin having a ring structure, such as a cellulose-based resin, is within the above range, the heat resistance and bag-making suitability of the laminate are good.

[0041] The content of nitrocellulose in the coating layer is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 1% by mass or less. When the content of nitrocellulose in the coating layer is within the above range, the colorability after heating is good.

[0042] In some embodiments, the content of the cellulose-based resin may be 55% by mass or more relative to 100% by mass of the resin (A). The content is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more. When the content of the cellulose-based resin is within the above range, the heat resistance and bag-making suitability of the laminate are good.

[0043] [Resin (B)] In some embodiments, the coating agent more preferably contains, as binder resins, a resin (A) having a glass transition point of 115°C or higher and a resin (B) having a glass transition point of less than 115°C. The glass transition point of resin (B) is preferably 100°C or lower, more preferably 90°C or lower, and even more preferably 80°C or lower. The glass transition point of resin (B) is preferably -50°C or higher, more preferably -30°C or higher, and even more preferably -10°C or higher. When the binder resin further contains resin (B), the glass transition point of the binder resin calculated as a weighted average with resin (A) is preferably 115°C or higher, more preferably 120°C to 250°C, even more preferably 120°C to 220°C, particularly preferably 130°C to 210°C, and most preferably 140°C to 200°C.

[0044] Specific examples of resin (B) include urethane resins, acrylic resins, epoxy resins, polyolefin resins, polyester resins, polyamide resins, polyimide resins, polyamideimide resins, vinyl chloride-vinyl acetate copolymer resins, polyvinyl butyral resins, and composite resins obtained by combining these resins, and the resin (B) may contain one or more of these. Among these, from the viewpoints of adhesion to olefin substrates and heat resistance, resin (B) preferably contains at least one selected from the group consisting of urethane resins, polyvinyl butyral resins, and polyamide resins, and more preferably is a urethane resin and / or a polyvinyl butyral resin.

[0045] When the coating agent contains resin (B), the content of resin (B) is preferably 20% by mass or less, more preferably 1 to 15% by mass, and even more preferably 2 to 10% by mass, based on the mass of the total solid content in the coating agent (100% by mass of the coating layer). When the content of resin (B) is within the above range, the adhesion and heat resistance of the laminate are good.

[0046] The mass average molecular weight of resin (B) is preferably 5,000 to 200,000, more preferably 8,000 to 150,000, and even more preferably 10,000 to 100,000. When the mass average molecular weight of resin (B) is within the above range, excellent adhesion and heat resistance are exhibited, and the heat resistance and bag-making suitability of the laminate are improved. The mass average molecular weight is measured by gel permeation chromatography (GPC).

[0047] In some embodiments, when the binder resin constituting the coating agent is a combination of two or more resins, the difference in the Hansen solubility parameters (HSP) of the two resins can be used as an indicator of their mutual solubility. HSP is an indicator of the solubility of a substance and is expressed by the dispersion term δd, the polar term δp, and the hydrogen bonding term δh. The HSP difference (Ra) between two substances is calculated from the difference Δδd in the dispersion term, the difference Δδp in the polar term, and the difference Δδh in the hydrogen bonding term between the two substances, as follows: Ra = {4 × Δδd2 + Δδp2 + Δδh2} １／２ It is expressed as follows. The smaller the Ra, the higher the compatibility, and the larger the Ra, the lower the compatibility. Details of the Hansen solubility parameters are described in Charles M. Hansen, Hansen Solubility Parameters; A Users Handbook (CRC Press, 2007). For substances for which literature values ​​are unknown, the values ​​can be calculated using solubility tests of the substance in multiple solvents and known computer software such as Hansen Solubility Parameters in Practice (HSPiP).

[0048] The combination of two resins may be, for example, a combination of two resins (A), specifically a combination of a cellulose-based resin and a polyamide. Another example is a combination of resin (A) and resin (B). While not particularly limited, a combination of resin (A) and resin (B) is preferred. In some embodiments, the HSP difference between the two resins is preferably 14 to 21, more preferably 15 to 21, and even more preferably 16 to 21. When the HSP difference is within the above range, a microphase-separated structure is easily formed. In particular, when the HSP difference between resin (A) and resin (B) is within the above range, the microphase-separated resin (B) adheres to the substrate surface, further improving adhesion between the coating layer and the substrate, and the microphase-separated resin (A) tends to further improve heat resistance. Note that the above description is based on technical considerations, and the present invention is not limited by theory.

[0049] [Particles] The coating agent forming the coating layer preferably contains particles. The inclusion of particles in the coating layer improves heat resistance and bag-forming suitability. While both organic and inorganic particles can be used, inorganic particles are preferred from the perspective of heat resistance. The particle content is preferably 1 to 90 mass% based on the mass of the total solids in the coating agent (100 mass% of the coating layer), more preferably 5 to 70 mass%, and even more preferably 10 to 60 mass%. When the particle content is within the above range, heat resistance and bag-forming suitability are improved. The average particle diameter of the particles is preferably 3,000 nm or less, more preferably 10 to 1,000 nm. In some embodiments, the average particle diameter of the particles is preferably 10 to 500 nm, more preferably 20 to 300 nm, and even more preferably 30 to 150 nm. In this specification, the average particle diameter is measured by dynamic light scattering, and the peak of the obtained volume particle size distribution (histogram) is taken as the average particle diameter.

[0050] (Inorganic Particles) In some embodiments, the coating agent forming the coat layer preferably contains inorganic particles. By including inorganic particles in the coat layer, the shrinkage ratio represented by the above formula (1) is reduced, and the heat resistance and bag-forming suitability of the laminate are improved. Examples of inorganic particles include extender pigments such as silica, calcium carbonate, barium sulfate, and silicon dioxide, and metal oxides such as titanium oxide, zinc oxide, iron oxide, and aluminum oxide. One or more of these may be included. In particular, from the viewpoint of heat resistance and bag-forming suitability, the coat layer preferably contains one or more particles selected from the group consisting of calcium carbonate, barium sulfate, titanium oxide, and zinc oxide. The coat layer more preferably contains one or more particles selected from the group consisting of calcium carbonate, barium sulfate, and zinc oxide, and even more preferably contains barium sulfate.

[0051] The content of inorganic particles is preferably 1 to 90% by mass, more preferably 5 to 70% by mass, and even more preferably 10 to 60% by mass, based on the mass of the total solids in the coating agent (100% by mass of the coating layer). When the content of inorganic particles is within the above range, heat resistance and bag-making suitability are improved. The average particle diameter of the inorganic particles is preferably 3,000 nm or less, and more preferably 10 to 1,000 nm. In some embodiments, the average particle diameter of the inorganic particles is preferably 10 to 500 nm, more preferably 20 to 300 nm, and even more preferably 30 to 150 nm.

[0052] In some embodiments, the oil absorption of the particles is preferably 100 ml / 100 g or less, more preferably 50 ml / 100 g or less, and even more preferably 30 ml / 100 g or less. The oil absorption can be measured based on JIS K5101-13-1. In some embodiments, the refractive index of the particles is preferably 2.5 or less, more preferably 2.0 or less, and even more preferably 1.8 or less. When particles having a refractive index within the above range are used, a coating layer with excellent transparency can be easily obtained.

[0053] From the viewpoint of forming a coating layer, the ratio of the mass of the particles to 100 mass% of the resin (A) in the coating agent is preferably 1 to 900 mass%, more preferably 10 to 233 mass%, even more preferably 20 to 150 mass%, and particularly preferably 30 to 100 mass%.

[0054] (Organic particles) Examples of organic particles include polyurethane-based resins, polynylon-based resins, polyacrylic-based resins, polysilicone-based resins, polystyrene-based resins, melamine-based resins, polyester-based resins, polyethylene-based resins, and benzoguanamine-based resins. The particles in the coating agent can contain one or more of these. Other preferred forms of organic particles are the same as those described above for inorganic particles.

[0055] [Additives] The coating agent that forms the coating layer may contain any additives, such as an adhesion promoter, a plasticizer, an amide wax, a hydrocarbon wax, a chelating crosslinking agent, etc. Among these, it is preferable to contain an adhesion promoter.

[0056] [Adhesion Imparting Agent] The coating agent for forming the coating layer preferably contains an adhesion imparting agent from the viewpoint of improving adhesion to the substrate. Examples of the adhesion imparting agent include chlorinated polyolefins and acid-modified polyolefins, and chlorinated polyolefins are particularly preferred.

[0057] [Chlorinated Polyolefin] The chlorine content of the chlorinated polyolefin is preferably 5 to 60% by mass, more preferably 10 to 50% by mass, and even more preferably 20 to 40% by mass, based on 100% by mass of the chlorinated polyolefin. Here, the chlorine content in the present invention refers to the mass % content of chlorine atoms in 100% by mass of the chlorinated polyolefin. Furthermore, from the viewpoint of solubility in a mixed solvent of an ester solvent and an alcohol solvent, the mass average molecular weight of the chlorinated polyolefin is preferably 5,000 to 80,000, more preferably 13,000 to 50,000. In some embodiments, the chlorine atom weight (mmol / g) may be 1.3 or less, 1.0 or less, 0.7 or less, or even 0, based on the total mass of the solids of the coating agent that forms the coating layer.

[0058] In this specification, chlorinated polyolefins have a structure in which hydrogen atoms in an α-olefin polymer represented by the following general formula (1) are substituted with chlorine atoms. General formula (1) CH ２ ═CH—R (wherein R is an alkyl group having one or more carbon atoms)

[0059] Chlorinated polyolefins have flexible alkyl groups in a branched structure, so they remain viscous even at low temperatures, improving the adhesion of the coating layer to the substrate. There are no particular restrictions on the polyolefin structure in chlorinated polyolefins, but resins containing homopolymers or copolymers of α-olefin-based unsaturated hydrocarbons, such as polypropylene, poly-1-butene, and poly-4-methyl-1-pentene, are preferred. Of these, those containing a polypropylene structure (i.e., a chlorinated polypropylene structure) are particularly preferred.

[0060] [Organic Solvent] Examples of organic solvents include non-aromatic organic solvents such as hydrocarbons such as methylcyclohexane and ethylcyclohexane; ketones such as acetone, methyl ethyl ketone (MEK), and methyl isobutyl ketone; esters such as ethyl acetate, n-propyl acetate, and butyl acetate; and alcohols such as methanol, ethanol, propanol, isopropanol (IPA), and butanol. The organic solvent may be appropriately selected taking into consideration factors such as reducing the amount of solvent remaining in the coating after printing. One type may be used alone, or two or more types may be mixed and used. The content of the organic solvent is preferably 30 to 95% by mass, more preferably 50 to 90% by mass, and particularly preferably 70 to 85% by mass, based on 100% by mass of the coating agent.

[0061] [Method for Producing Coating Agent] The coating agent for forming the coating layer preferably contains the binder resin and / or the inorganic particles. Furthermore, to improve the handling, heat resistance, and bag-making suitability of the coating agent, optional components such as the adhesion promoter, organic solvent, co-resin, and other additives can be added to the coating agent, either singly or in combination. The coating agent can be obtained, for example, by charging a resin solution in which a resin is dissolved in an organic solvent and / or inorganic particles, and an organic solvent into a mixer equipped with a stirring blade, rotor, or the like, and mixing and stirring the mixture. The stirring speed is not particularly limited, and can be set at 50 to 30,000 rpm.

[0062] <Substrate 1 and Substrate 2> The substrate 1 and the substrate 2 described later may be single layers, may be simply laminated together with plastic substrates, or may be laminated with a substrate different from the plastic substrate via an adhesive layer or the like. Furthermore, the "substrate different from the plastic substrate" may be, for example, a plastic substrate and a paper substrate having different properties, and any type of substrate may be used. Furthermore, in the case of a laminated substrate, it may include an adhesive layer. The method for laminating the substrates is not particularly limited, and examples thereof include conventionally known methods such as coextrusion, heat fusion, and pressure bonding via an adhesive layer.

[0063] The substrate 1 and the substrate 2 described below preferably contain additives such as antistatic agents, antifogging agents, and ultraviolet protection agents by coating or kneading, have an easily adhesive coating layer (e.g., a layer containing polyvinyl alcohol and / or its derivatives), or have a substrate surface that has been corona-treated or low-temperature plasma-treated. The above-mentioned additions and processing are also carried out for the purpose of improving the wettability of printing inks and other coating agents or for the purpose of imparting specific functionality to the film, and are suitably used, for example, to provide a packaging material that has excellent visibility of the contents by preventing fogging of the packaging material due to moisture.

[0064] In some embodiments, the substrate 1 preferably contains a polyolefin-based resin. A polyolefin-based resin film can be suitably used. Examples of suitable films include biaxially oriented polypropylene (OPP) film, unoriented polypropylene (CPP) film, polypropylene films such as acid-modified polypropylene and copolymer polypropylene, polyethylene films such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), and acid-modified polyethylene, and multilayer films formed by laminating these films. Among these, films of low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), medium-density polyethylene (MDPE), and high-density polyethylene (HDPE) are preferred. The thickness of the substrate 1 is not particularly limited. In some embodiments, the thickness of the substrate 1 is preferably 5 μm or more and 150 μm or less, more preferably 10 μm or more and 70 μm or less.

[0065] In some embodiments, the surface of the substrate 1 on which the coating layer is formed is preferably subjected to a corona treatment. The oxygen element ratio on the corona-treated surface of the substrate 1 is preferably 2% or more, more preferably 3% or more, and even more preferably 4% or more. The oxygen element ratio on the surface of the substrate 1 is the oxygen atom composition ratio when narrow measurement of carbon atoms and oxygen atoms is performed using an X-ray photoelectron spectrometer. The measurement conditions using the X-ray photoelectron spectrometer may be, for example, as follows. (Measurement conditions) - Apparatus: ULVAC - PHI Corporation, Quantera SXM - X-ray source: Monochrome AlKα - X-ray setting: 100 μmφ [15 kV, 25 W] - Photoelectron take-off angle: 45° relative to the sample surface - Bond energy correction: The peak derived from the C-C bond in the C1s spectrum is corrected to 285.0 eV - Charge neutralization conditions: Use of an electron neutralization gun and an Ar ion gun (neutralization mode) in combination

[0066] In some embodiments, the substrate 1 is preferably a uniaxially stretched substrate or a biaxially stretched substrate from the viewpoint of printability and processability. The uniaxially stretched substrate is a film stretched in the machine direction (MD). It can be obtained by any appropriate film forming method, but is preferably obtained by stretching a sheet shaped by the T-die method. The stretching ratio in the machine direction (MD) of the uniaxially stretched substrate is preferably 2 to 10 times, more preferably 2 to 8 times. The biaxially stretched substrate is a film stretched in the machine direction (MD) and the transverse direction (TD).

[0067] Films that can be used as substrates, like the base films of conventional laminate films, can generally be shaped using the T-die method, stretched in the machine direction (MD), and then stretched in the transverse direction (TD). Biaxial stretching can be performed by either sequential biaxial stretching or simultaneous biaxial stretching, as described above, and either method is effective. The preferred stretch ratio in the machine direction (MD) of a biaxially stretched substrate is 2 to 10 times, more preferably 2 to 8 times. The preferred stretch ratio in the transverse direction (TD) is 2 to 10 times, more preferably 4 to 10 times. When a stretched film is heated and pressurized, a force acts to return the film from its post-stretched state to its pre-stretched state. Therefore, the higher the stretch ratio, the greater the thermal shrinkage rate, but the stretching direction does not affect the thermal shrinkage rate. For example, if a uniaxially stretched film can satisfy the thermal shrinkage rate in the stretching direction, the uniaxially stretched film will also satisfy the thermal shrinkage rate in the non-stretching direction (perpendicular to the stretching direction).

[0068] The polyolefin contained in the substrate 1 has a density of 0.860 to 0.970 g / cm ３ Among these, polyethylene having a density of 0.940 to 0.970 g / cm is preferred. ３ , an ethylene homopolymer or a copolymer component of ethylene and an olefin comonomer having an MFR of 0.1 to 10 g / 10 min, a density of 0.860 to 0.926 g / cm ３ and copolymer components of ethylene and olefin comonomers having an MFR of 1.0 to 30.0 g / 10 min.

[0069] The substrate 2 contains a polyolefin resin and may be the same as or different from the substrate 1, but is preferably a sealant layer. A sealant layer refers to a layer having heat-sealing properties. The substrate 2 is preferably the outermost layer of the laminate. The description of the substrate 1 above can be used to refer to the polyolefin resin contained in the substrate 2. Among these, the substrate 2 is preferably a non-oriented polypropylene (CPP) film, low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), medium-density polyethylene (MDPE), or high-density polyethylene (HDPE). The melting point of the substrate 2 is preferably 80°C to 140°C, more preferably 90°C to 120°C. The film thickness of the substrate 2 is preferably 20 to 200 μm, more preferably 20 to 100 μm, and even more preferably 20 to 60 μm.

[0070] Although not particularly limited, in the combination of substrate 1 and substrate 2, substrate 1 may be a uniaxially oriented polyethylene film, a biaxially oriented polyethylene film, an unstretched high-density polyethylene film, or a biaxially oriented polypropylene film, and substrate 2 may be an unstretched linear low-density polyethylene film or an unstretched polypropylene film.

[0071] <Adhesive Layer> The laminate of this embodiment includes an adhesive layer. The components of the adhesive layer are not particularly limited, and suitable examples include dry lamination adhesives and non-solvent lamination adhesives such as olefin-based adhesives, acrylic-based adhesives, ethylene-vinyl acetate copolymer-based adhesives, and reactive urethane adhesives; imine-based anchor coating agents, butadiene-based anchor coating agents, isocyanate-based anchor coating agents; and thermoplastic resins used in extrusion lamination. In some embodiments, the adhesive layer preferably contains a reaction product of a reactive urethane adhesive composed of polyisocyanate and polyol. The adhesive layer may contain an inorganic compound to improve the barrier properties of the laminate. The thickness of the adhesive layer is preferably 0.5 μm to 20 μm, more preferably 0.8 μm to 5 μm, and even more preferably 1.0 μm to 4.5 μm.

[0072] The mass average molecular weight (Mw) of the polyol is preferably 2,000 to 80,000, more preferably 5,000 to 60,000, and even more preferably 10,000 to 60,000. Furthermore, using a polyol with a molecular weight distribution (Mw / Mn) of 1.5 to 10 can improve the leveling properties during adhesive application and the laminate strength between layers. In particular, when the polyol contains structural units derived from polyether polyol, the molecular weight distribution (Mw / Mn) is preferably 3.0 to 10.0, more preferably 3.0 to 8.0. When the polyol contains structural units derived from polyester polyol, the molecular weight distribution (Mw / Mn) is preferably 1.5 to 5.0, more preferably 2.0 to 4.0.

[0073] The acid value of the polyol is not particularly limited, but is preferably 0 to 50 mgKOH / g, more preferably 0 to 40 mgKOH / g. The hydroxyl value of the polyol is not particularly limited, but is preferably 1 to 200 mgKOH / g, more preferably 3 to 150 mgKOH / g.

[0074] [Isocyanate Curing Agent] The isocyanate curing agent functions as a curing agent in the reactive adhesive. It is suitable for use in ordinary two-component reactive adhesives, and any isocyanate curing agent can be used as long as it contains a functional group reactive with a hydroxyl group. The presence of an isocyanate group increases the adhesive strength and cohesive force of the adhesive, and also enables curing at low temperatures around room temperature.

[0075] As the isocyanate curing agent, diisocyanate or a urethane prepolymer which is a reaction product of diisocyanate and polyol, etc. are preferred. As the diisocyanate, various known aromatic, aliphatic or alicyclic diisocyanates can be used. For example, 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyl isocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, tolylene diisocyanate, butane-1,4-diisocyanate, hexamethylene diisocyanate, isopropylene diisocyanate, methylene diisocyanate, 2,2, Examples of such diisocyanates include 4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, cyclohexane-1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, lysine diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, methylcyclohexane diisocyanate, m-tetramethylxylylene diisocyanate, and dimer diisocyanate in which the carboxyl groups of dimer acid are converted to isocyanate groups. These may be used alone or in combination of two or more.

[0076] In the adhesive layer, the functional group equivalent ratio NCO / OH between the hydroxyl group derived from the polyol and the isocyanate group derived from the isocyanate resin is preferably 1.5 to 8.0, more preferably 2.0 to 5.0. Other components known for adhesives can be blended into the base agent or curing agent of the adhesive.

[0077] Usable commercially available polyols include TM-320 and TM-340 manufactured by Toyo-Morton Co., Ltd. Usable commercially available isocyanate curing agents include CAT-13B and CAT-29B manufactured by Toyo-Morton Co., Ltd.

[0078] The laminate of this embodiment may include additional layers depending on the intended use, in addition to the substrate 1, adhesive layer, substrate 2, and coating layer. For example, it may further include a printed layer, a vapor deposition layer, a barrier layer, an intermediate substrate, etc., which will be described later. <Printed Layer> The laminate of this embodiment may have a printed layer. The printed layer preferably includes a resin and a colorant. The printed layer may be a layer that displays any design, pattern, letter, symbol, etc., for the purpose of providing decoration or aesthetic appeal; indicating the contents, expiration date, manufacturer or seller, etc. The printed layer may also be a solid printed layer that does not have any design, pattern, letter, symbol, etc. The method for forming the printed layer is not particularly limited, and it can be formed using printing ink. The printed layer may be a single-layer or multi-layer structure, and may be printed on the surface layer of the laminate. The mass per unit area of ​​the printed layer is 0.1 to 12 g / m ２ It is preferable that the density is 0.5 to 6 g / m ２ More preferably, it is 1 to 3 g / m ２ It is more preferable that:

[0079] <Vapor-deposited layer and barrier layer> The laminate of this embodiment may have a vapor-deposited layer and / or a barrier layer for the purpose of controlling the gas permeability of the film. The vapor-deposited layer is present for the purpose of imparting oxygen barrier properties and / or water vapor barrier properties to the laminate, and examples thereof include vapor-deposited layers made of metal oxides such as aluminum oxide, silicon oxide, magnesium oxide, and tin oxide. The barrier layer is present mainly for the purpose of imparting oxygen barrier properties to the laminate, and preferably contains a polyvinyl alcohol-based resin. The barrier layer may have any known form, but is preferably a barrier coating layer formed from a barrier coating agent.

[0080] <Intermediate Substrate> The laminate of this embodiment may have an intermediate substrate. A specific example of the intermediate substrate is preferably a plastic substrate primarily containing a polyolefin resin as a raw material, similar to substrate 1 and substrate 2. Examples include polyolefin resins such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), ethylene-vinyl acetate copolymer, propylene homopolymer, and ethylene-propylene copolymer. Alternatively, the intermediate substrate may be a composite substrate manufactured by co-extrusion. Furthermore, the intermediate substrate is preferably made of the same (same) material as substrate 1 and / or substrate 2, and more preferably made of the same (same) material as substrate 1 and substrate 2. Examples of materials of the same (same) type include combinations of polypropylene and polyethylene, etc.

[0081] When the laminate has the additional layers, typical examples of the laminate configuration include the following: Coat layer / substrate 1 / printed layer / adhesive layer / substrate 2 Coat layer / substrate 1 / printed layer / barrier layer / adhesive layer / substrate 2 Coat layer / substrate 1 / printed layer / adhesive layer / intermediate substrate layer / adhesive layer / substrate 2

[0082] <2> Manufacturing Method of Laminate One embodiment of the present invention relates to a manufacturing method of the laminate of the above embodiment. The manufacturing method includes the steps of printing a coating agent on one or both surfaces of the base layer 1 to form a coat layer, printing an adhesive on the base layer 1 or the coat layer to form an adhesive layer, and bonding the base material 2 onto the adhesive layer.

[0083] <Printing method of coating layer> The method for forming the coating layer is not particularly limited, and the coating layer can be formed by printing a coating agent using a known printing method and removing volatile components. Examples of the printing method include plateless printing methods such as inkjet printing, spraying, dipping, slot die printing, and spin coating; and plate printing methods such as offset gravure coater, gravure coater, doctor coater, kiss coater, bar coater, blade coater, flexo coater, and roll coater.

[0084] <Method of Forming Adhesive Layer and Method of Bonding Each Layer> The method of forming the adhesive layer and the method of bonding each layer are not particularly limited, and examples thereof include conventionally known methods such as extrusion lamination, dry lamination, and non-sol lamination.

[0085] <3> Packaging Material The laminate of this embodiment can be suitably used for packaging materials such as packaging bags. A packaging bag can be produced, for example, by folding the laminate so that the sealant layers overlap, and then applying pressure with a high-temperature jig to sandwich the laminate and heat seal it. Similarly, two laminates can also be stacked and heat sealed to produce a bag. The laminate of this embodiment can be suitably used for packaging bags, particularly gusseted packaging bags such as gusseted bags and stand-up bags.

[0086] Gusset bags can be manufactured, for example, by the method described in JP 2020-059535 A. In gusset bags, the joints that form the bag are made of multiple overlapping layers of packaging material, resulting in a thick film thickness, making it difficult for heat to be transmitted to the interior during heat sealing. For this reason, in the manufacture of gusset bags, a high heat sealing temperature must often be set in order to transmit heat to the interior of the overlapping joints of the packaging material. For these reasons, in the manufacture of gusset bags, the surface of the packaging material that comes into direct contact with the heat sealing tool must have high heat resistance. A similar high heat resistance is required in the manufacture of stand-up bags. In contrast, the laminate of this embodiment has excellent heat resistance and can be suitably used as a packaging material not only for general packaging bags but also for cases requiring high heat resistance, such as gusset bags.

[0087] In recent years, there has been a demand for improved recyclability of packaging materials, and for packaging materials (laminates) that are less likely to discolor due to heat. One method for recycling monomaterial packaging materials is heat-melt kneading using an extruder or the like. Because the heating temperature during melt kneading is higher than the heat-sealing temperature during packaging bag production, there is a high possibility that the resin will discolor due to heating during recycling. In contrast, the laminate of the present embodiment has excellent heat resistance, making it possible to easily suppress discoloration due to heating and pressure during packaging bag production, thereby achieving a packaging material with excellent recyclability. In some embodiments, when a nitrocellulose resin is contained in the coating layer, components in the nitrocellulose resin react with the substrate due to heat, which tends to cause discoloration of the substrate. From this perspective, adjusting the content of the nitrocellulose resin in the coating layer makes it easier to suppress discoloration of the substrate due to heat.

[0088] Examples of embodiments of the present invention are described below. However, the present invention is not limited to the embodiments described below. [1] A laminate having a substrate 1, an adhesive layer, and a substrate 2 in this order, and further having a coating layer, wherein the substrate 1 and the substrate 2 contain a polyolefin resin, and when heated and pressed under the following heating and pressing conditions, the shrinkage ratio of the laminate, expressed by the following (Equation 1), is 30 area % or less. (Heating and pressing conditions) Heating temperature: 145°C, pressure: 2 kg / cm ２ Heating and pressing time: 1 second (Formula 1) Shrinkage rate (area %)={1-(area after heating and pressing) / (area before heating and pressing)}×100

[0089] [2] A laminate having a coating layer and a substrate 1, wherein the substrate 1 contains a polyethylene resin, and when heated and pressed under the following heating and pressing conditions, the laminate has a shrinkage ratio represented by the following (Equation 1) of 30 area % or less. (Heating and pressing conditions) Heating temperature: 145°C, pressure: 2 kg / cm ２ Heating and pressing time: 1 second (Formula 1) Shrinkage rate (area %)={1-(area after heating and pressing) / (area before heating and pressing)}×100

[0090] [3] The laminate according to the above [1], wherein the polyolefin resin is a polyethylene resin.

[0091] [4] The laminate according to any one of [1] to [3] above, wherein the difference between the peak temperature of the loss tangent (tan δ) of the laminate and the peak temperature of the tan δ of the laminate excluding the coating layer, measured at 80°C to 170°C according to JIS K 7244, is 1.0°C or more.

[0092] [5] The laminate according to any one of the above [1] to [4], wherein the coating layer contains a resin (A) having a glass transition point of 120°C or higher.

[0093] [6] The laminate according to the above [5], wherein the resin (A) is a cellulose-based resin.

[0094] [7] The laminate according to any one of [1] to [6], wherein the coating layer contains a chlorinated polyolefin resin.

[0095] [8] The laminate according to any one of [1] to [7], wherein the coating layer contains inorganic particles.

[0096] [9] A method for producing a laminate having a substrate 1, an adhesive layer, and a substrate 2 in this order, and further having a coating layer, the method comprising the steps of printing a coating agent to form the coating layer, printing an adhesive to form the adhesive layer, and laminating the substrate 2 onto the adhesive layer, wherein the shrinkage rate of the laminate, expressed by the following formula (1), when heated and pressed under the following heating and pressing conditions is 30 area % or less. (Heating and pressing conditions) Heating temperature: 145°C, pressure: 2 kg / cm ２ Heating and pressing time: 1 second (Formula 1) Shrinkage rate (area %)={1-(area after heating and pressing) / (area before heating and pressing)}×100

[0097] The disclosure of this application is related to the subject matter described in Japanese Patent Application No. 2023-126372, filed on August 2, 2023, the entire disclosure of which is incorporated herein by reference.

[0098] The present invention will be described below with reference to examples, but is not limited to these. In the examples and comparative examples, "parts" and "%" mean "parts by mass" and "% by mass" unless otherwise specified.

[0099] The various measurement methods are as follows. <Glass transition point> The glass transition point of the resin was measured by DSC (differential scanning calorimeter manufactured by TA Instruments). Specifically, about 2 mg of a sample obtained by drying the coating agent was weighed on an aluminum pan, and the aluminum pan was set in a DSC measurement holder. The glass transition point was obtained by reading the baseline shift to the endothermic side in the DSC curve obtained under the temperature rising condition of 5°C / min.

[0100] <Weight average molecular weight> The weight average molecular weight was determined by measuring the molecular weight distribution using a gel permeation chromatography (GPC) apparatus (HLC-8220 manufactured by Tosoh Corporation) and calculating the molecular weight as a converted value using polystyrene as a standard substance. The measurement conditions are shown below. (Measurement conditions) Column: The following columns were connected in series and used. TSKgel Super AW2500 manufactured by Tosoh Corporation TSKgel Super AW3000 manufactured by Tosoh Corporation TSKgel Super AW4000 manufactured by Tosoh Corporation TSKgelguard column Super AWH manufactured by Tosoh Corporation Detector: RI (differential refractometer) Measurement temperature: Column temperature 40°C Eluent: Tetrahydrofuran Flow rate: 1.0 mL / min

[0101] <Amine Value> The amine value is the amount of potassium hydroxide (mg) equivalent to the amount of hydrochloric acid required to neutralize the amino groups contained in 1 g of sample, and was measured in accordance with JIS K 0070. 0.5 to 2 g of sample was precisely weighed (sample solids: S g), and 50 mL of a 60 / 40 (mass ratio) mixed solution of methanol and methyl ethyl ketone was added to the precisely weighed sample for dissolution. Bromophenol blue was added as an indicator to the resulting solution, and the resulting solution was titrated with a 0.2 mol / L ethanolic hydrochloric acid solution (titer: f). The point at which the solution changed color from green to yellow was defined as the endpoint, and the titration volume (A mL) at this point was used to calculate the amine value according to the following formula: (Formula 3) Amine value = (A × f × 0.2 × 56.108) / S [mg KOH / g]

[0102] <Heat Shrinkage Rate> The laminate was cut into a size of 50 mm x 25 mm (when the substrate contained a uniaxially stretched film, the long side was 50 mm in the stretching direction), and heated and pressed in a 20 mm x 10 mm area as shown in Figures 1 and 2 using a heat seal tester, and the shrinkage rate was calculated using the following formula (1). The heating and pressing conditions were a heating temperature of 145°C and a pressure of 2 kg / cm. ２ The heating and pressing time was 1 second. (Formula 1) Shrinkage rate (area %)={1-(area after heating and pressing) / (area before heating and pressing)}×100

[0103] <Peak Temperature Difference of Loss Tangent> For the laminate having a coating layer and the laminate excluding the coating layer, the peak temperatures of the loss tangent (tan δ) were measured between 80°C and 200°C according to JIS K 7244. Next, the difference between the peak temperature of the loss tangent (tan δ) of the laminate having the coating layer and the peak temperature of tan δ of the laminate excluding the coating layer was calculated as shown in the following (Equation 2): (Equation 2) Difference in Peak Temperature of Tan δ = (Peak Temperature of Tan δ of Laminate Having Coating Layer) - (Peak Temperature of Tan δ of Laminate excluding Coating Layer)

[0104] <Elemental ratio of oxygen on the surface of substrate 1> Narrow measurement of carbon atoms and oxygen atoms was performed using an X-ray photoelectron spectrometer to determine the elemental ratio of oxygen on the surface of substrate 1, and the composition ratio of oxygen atoms was determined. The measurement conditions for the X-ray photoelectron spectrometer are as follows: (Measurement conditions) - Apparatus: ULVAC - Phi Corporation Quantera SXM - X-ray source: Monochrome AlKα - X-ray setting: 100 μmφ [15 kV, 25 W] - Photoelectron take-off angle: 45° relative to the sample surface - Bond energy correction: The peak derived from the C-C bond in the C1s spectrum is corrected to 285.0 eV - Charge neutralization conditions: Use of an electron neutralization gun and an Ar ion gun (neutralization mode) in combination.

[0105] <Synthesis of Binder Resins> [Synthesis Example 1] Synthesis of Urethane Resin A A four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube was charged with 24.2 parts of a polyester polyol (a condensate of neopentyl glycol, 1,3-propanediol, adipic acid, and sebacic acid), 4 parts of isophorone diisocyanate, 10 parts of ethyl acetate, and 0.003 parts of tin 2-ethylhexanoate. The mixture was reacted at 120°C for 6 hours under a nitrogen stream, and 14 parts of propyl acetate was added and cooled to obtain a solution of a terminal isocyanate prepolymer. Next, the previously prepared solution of the terminal isocyanate prepolymer was gradually added at room temperature to a mixture of 1.7 parts of isophorone diamine, 0.2 parts of n-dibutylamine, 18 parts of ethyl acetate, and 28 parts of isopropyl alcohol. After the addition, the mixture was reacted at 50°C for 1 hour to obtain a urethane resin A solution with a solids content of 30%. Urethane resin A had a mass average molecular weight of 70,000, an amine value of 4 mgKOH / g, and a glass transition temperature of -42°C.

[0106] Synthesis Example 2 Synthesis of Urethane Resin B A four-neck flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube was charged with 195 parts of Polylite RX-4800 (DIC Corporation, polycarbonate polyol, solids content 100%), 5 parts of 1,4-butanediol, 44.2 parts of isophorone diisocyanate, and 61.1 parts of ethyl acetate, and the mixture was allowed to react at 80°C for 4 hours under a nitrogen stream to obtain a solvent solution of a terminal isocyanate prepolymer. Next, the previously prepared terminal isocyanate prepolymer solution was gradually added at 40°C to a mixture of 8.21 parts of isophorone diamine and 527.9 parts of a 50 / 50 ethyl acetate / isopropanol mixed solvent. After the addition, the mixture was allowed to react at 80°C for 1 hour to obtain a urethane resin B solution with a solids content of 30%. Urethane resin B had a glass transition point of 40° C., an amine value of 6.0 mgKOH / g, and a weight average molecular weight of 60,000.

[0107] [Synthesis Example 3] Synthesis of Urethane Resin C A four-neck flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube was charged with 195 parts of a polyester polyol (a condensate of adipic acid and 2-methyl-1,5-propanediol), 5 parts of 1,4-butanediol, 44.2 parts of isophorone diisocyanate, and 61.1 parts of ethyl acetate. The mixture was reacted at 80°C for 4 hours under a nitrogen stream to obtain a solvent solution of a terminal isocyanate prepolymer. Next, the previously prepared terminal isocyanate prepolymer solution was gradually added at 40°C to a mixture of 8.21 parts of isophorone diamine and 527.9 parts of a 50 / 50 ethyl acetate / isopropanol mixed solvent. After the addition, the mixture was reacted at 80°C for 1 hour to obtain a urethane resin C solution with a solids content of 30%. The urethane resin C had a glass transition point of 0°C, an amine value of 7.0 mgKOH / g, and a weight average molecular weight of 59,000.

[0108] <Production of Coating Agents> [Production Example 1] Coating Agent 1 5.0 parts of barium sulfate (average particle size: 0.05 μm, solids content 100%, oil absorption 20 ml / 100 g, refractive index 1.64), 0.1 parts of BYK-111 (manufactured by BYK-Chemie, resin with acidic functional groups, solids content 95%), 8.0 parts of ethyl acetate, 1.0 parts of 2-propanol, and 1.0 parts of propylene glycol monomethyl ether were stirred and mixed, and then dispersed in a bead mill (using zirconia beads). 18.0 parts of nitrocellulose resin solution DLX5-8 (manufactured by ICI Novel Enterprises, nitrocellulose, nitrogen content 12.0%, solids content 30%, 2-propanol solution) and 0.7 parts of Superchlorine 370M (chlorinated polypropylene) were added to the mixture obtained by the above dispersion treatment and stirred and mixed to obtain Coating Agent 1. The glass transition temperature of the nitrocellulose resin in Coating Agent 1 was 130°C.

[0109] [Production Examples 2 to 19] Coating agents 2 to 19 Coating agents 2 to 19 were obtained in the same manner as in Production Example 1, except that the raw materials and compounding ratios shown in Table 1 were used. Cellulose acetate propionate (CAP), cellulose acetate butyrate (CAB), and cellulose acetate (CA) were each used as a resin solution with a solids content adjusted to 30% using a mixed solvent of ethyl acetate / 2-propanol / propylene glycol monomethyl ether = 8 / 1 / 1.

[0110] Details of the raw materials used in Production Examples 2 to 19 and listed in Table 1 are shown below. Raw materials not listed below are as explained in Production Example 1. (Inorganic particles) Calcium carbonate: average particle size: 0.08 μm, solid content 100%, oil absorption 54 ml / 100 g, refractive index 1.9 to 2.0) Zinc oxide: average particle size: 0.1 μm, solid content 100%, oil absorption 32 ml / 100 g, refractive index

[0111] (Binder resins) S-2800: Polyamide resin manufactured by Kao Corporation, glass transition point 115°C, mass average molecular weight 3500 (solid content 30% 2-propanol / toluene = 30 / 70 solution) CAP-482-0.5: Cellulose acetate propionate manufactured by Eastman Co., glass transition point 142°C, mass average molecular weight 25000 CAP-504-0.2: Cellulose acetate propionate manufactured by Eastman Co., glass transition point 159°C, mass average molecular weight 15000 CAP-482-20: Cellulose acetate propionate manufactured by Eastman Co., glass transition point 147°C, mass average molecular weight 75000 CAB-553-0.4: Cellulose acetate butyrate manufactured by Eastman Co., glass transition point 136°C, mass average molecular weight 20000 CAB-531-1: cellulose acetate butyrate manufactured by Eastman, glass transition point 115°C, mass average molecular weight 10,000 CAB-381-0.5: cellulose acetate butyrate manufactured by Eastman, glass transition point 130°C, mass average molecular weight 30,000 CAB-321-0.1: cellulose acetate butyrate manufactured by Eastman, glass transition point 127°C, mass average molecular weight 12,000 CAB-171-15: cellulose acetate butyrate manufactured by Eastman, glass transition point 161°C, mass average molecular weight 65,000 CA-398-3: cellulose acetate manufactured by Eastman, glass transition point 180°C, mass average molecular weight 30,000

[0112]

[0113] [Production Example 20] Coating Agent 20 Takelac W-5030 (polyurethane resin manufactured by Mitsui Chemicals, Inc.) and Takenate WD-725 (manufactured by Mitsui Chemicals, Inc.) as a curing agent were mixed at a solids ratio of 9:1, and the mixture was diluted with a solvent (water / 2-propanol = 9 / 1) to a solids content of 5 mass % to prepare Coating Agent 20. The glass transition temperature of the resin in the coating agent was 85°C, and the mass average molecular weight could not be measured.

[0114] [Production Example 21] Coating agent 21 Vylomax HR-15ET (a polyamideimide resin manufactured by Toyobo Co., Ltd.) was diluted with a solvent (ethanol / toluene = 1 / 1) to a solids content of 5 mass % to prepare coating agent 21. The resin in the coating agent had a glass transition temperature of 260°C and a mass average molecular weight of 6,000.

[0115] [Production Example 22] Coating agent 22 jER1004 (an epoxy resin manufactured by Mitsubishi Chemical Corporation) and Coronate L (manufactured by Tosoh Corporation) as a curing agent were mixed in a solids ratio of 9:1, and the mixture was diluted with a solvent (ethanol / toluene = 1 / 1) to a solids content of 5 mass% to prepare coating agent 22. The glass transition temperature of the resin in the coating agent was 104°C.

[0116] [Production Example 23] Coating Agent 23 20 parts of polyamide resin solution S-2800 (30% solids), 20 parts of cellulose resin solution DLX5-8 (30% solids), 30 parts of inorganic pigment CR-80 (100% solids, manufactured by Ishihara Sangyo Kaisha, Ltd., rutile crystal structure, surface treatment with silica and alumina, average particle size 0.25 μm, oil absorption 20 ml / 100 g), 0.8 parts of hydrocarbon wax (100% solids, penetration 13, melting point 110°C), 20.4 parts of propyl acetate, and 8.8 parts of 2-propanol were mixed. The resulting mixture was kneaded and dispersed in a sand mill for 20 minutes to obtain Coating Agent 23.

[0117] [Production Example 24] Coating Agent 24 5.0 parts of calcium carbonate (average particle size: 0.08 μm, solids content 100%, oil absorption 54 ml / 100 g, refractive index 1.6), 0.1 parts of DA-375 (manufactured by BYK-Chemie, resin having an acidic functional group, solids content 95%), 8.0 parts of ethyl acetate, 1.0 part of 2-propanol, and 1.0 part of propylene glycol monomethyl ether were mixed with stirring. The resulting mixture was dispersed using a bead mill (using zirconia beads), and then 12.0 parts of CAP-504-0.2 and 1.2 parts of VINNOL E 15 / 40A were added and mixed with stirring to obtain Coating Agent 24.

[0118] [Production Examples 25 to 41] Coating agents 25 to 41 Coating agents 25 to 41 were obtained in the same manner as in Production Example 24, except that the raw materials and compounding ratios shown in Table 2 were used. Cellulose acetate propionate (CAP) and cellulose acetate butyrate (CAB) were each used as a resin solution with a solids content adjusted to 30% using a mixed solvent of ethyl acetate / 2-propanol / propylene glycol monomethyl ether = 8 / 1 / 1.

[0119] Details of the raw materials used in Production Examples 25 to 41 and listed in Table 2 are shown below. Raw materials not listed below are as explained in Production Example 24. (Inorganic particles) Calcium carbonate: average particle size: 0.08 μm, solid content 100%, oil absorption 54 ml / 100 g, refractive index 1.9 to 2.0) (Dispersants) BYK-W9011: BYK-Chemie, dispersant having an acidic functional group, solid content 95% DA-375: Kusumoto Chemicals Co., Ltd., polyether phosphate ester, solid content 100% (Binder resin A) NC: nitrocellulose resin solution DLX5-8 (ICI Novel Enterprises, nitrocellulose, nitrogen content 12.0%, solid content 30%, 2-propanol solution, glass transition point 130° C.) CAB-553-0.4: Eastman Cellulose Acetate Butyrate, glass transition point 136° C., mass average molecular weight 20,000 CAP: CAP-504-0.2 (cellulose acetate propionate manufactured by Eastman Co., glass transition point 159°C, mass average molecular weight 15,000) (binder resin B) PVC / CA: VINNOL E 15 / 40A (vinyl chloride vinyl acetate copolymer manufactured by WACKER, K value 39, glass transition point 69°C) PVB: S-LEC BL-1 (polyvinyl butyral resin manufactured by Sekisui Chemical Co., Ltd., glass transition point 70°C, mass average molecular weight 19,000) Polyurethane resin A: resin prepared in Synthesis Example 1 of polyurethane resin A. glass transition point -42°C, mass average molecular weight 70,000 Polyurethane resin B: resin prepared in Synthesis Example 2 of polyurethane resin B. glass transition point 40°C, mass average molecular weight 60,000 Polyurethane resin C: resin prepared in Synthesis Example 3 of polyurethane resin C.Glass transition point 0°C, mass average molecular weight 59,000 S-2800: Polyamide resin manufactured by Kao Corporation, glass transition point 115°C, mass average molecular weight 3,500 (solid content 30%, 2-propanol / toluene = 30 / 70 solution, softening point 115°C). Cellulose acetate propionate (CAP), vinyl chloride / vinyl acetate resin (PVC / VA), polyvinyl butyral (PVB), and polyurethane (PU) were each used as a resin solution adjusted to a solid content of 30% using a mixed solvent of ethyl acetate / 2-propanol / propylene glycol monomethyl ether = 8 / 1 / 1.

[0120]

[0121] <Laminate Production> [Example 1] Coating agent 1 was diluted with a mixed solvent (isopropyl alcohol / ethyl acetate) to a solids content of 15%. A uniaxially stretched polyethylene film MDOPE (surface oxygen element ratio 10.2%, thickness 25 μm) that had been corona-treated on both sides was prepared as substrate 1. The diluted Coating agent 1 was printed on the corona-treated surface of substrate 1 to form a coating layer. Coating agent 1 was printed using a gravure printing machine equipped with a gravure plate with a plate depth of 60 μm, at a printing speed of 50 m / min, and in an in-line oven temperature of 60°C. Next, a polyether-based reactive urethane adhesive ("TM-340V / CAT-29B" manufactured by Toyo-Morton) was applied to the corona-treated surface of substrate 1 opposite the surface on which the coating layer was formed, using a dry laminating machine equipped with a gravure plate with a plate depth of 40 μm, to form an adhesive layer. A low-density polyethylene (LLDPE) film (thickness: 60 μm) was then bonded onto the adhesive layer as substrate 2 to produce a laminate film. The laminate film produced as described above was stored at 40°C for 1 day to obtain a laminate having the structure (1) (coating layer / substrate 1 / adhesive layer / substrate 2). The thermal shrinkage of the obtained laminate was 0.1% or less, and the peak temperature difference of the loss tangent was 1.5°C.

[0122] [Examples 2 to 5, 7 to 20, 23 to 29, Comparative Examples 1 to 3, 5] Laminates were obtained in the same manner as in Example 1, except that the configuration, coating agent, and printing conditions for the coating agent were changed as shown in Table 3. In Example 3, a high-density polyethylene (HDPE) film (thickness 25 μm) was used as the substrate 1. In Example 5, a biaxially oriented polypropylene (OPP) film (thickness 25 μm) was used as the substrate 1, and a non-oriented polypropylene (CPP) film was used as the substrate 2. In Comparative Examples 1 to 3 and 5, the samples melted during shrinkage measurement, making it impossible to measure the shrinkage.

[0123] Example 6: A coating layer was formed by printing diluted Coating Agent 3 on the corona-treated surface of a double-sided corona-treated uniaxially oriented polyethylene (MDOPE) film (thickness: 25 μm) as the substrate 1 using a gravure printing machine equipped with a gravure plate having a plate depth of 60 μm at a printing speed of 50 m / min and an in-line oven temperature of 60°C, thereby obtaining a laminate having the structure (4) (coating layer / substrate 1). The thermal shrinkage of the obtained laminate was 0.1% or less, and the peak temperature difference of the loss tangent was 1.5°C.

[0124] [Example 21] As the substrate 1, a double-sided corona-treated uniaxially oriented polyethylene (MDOPE) film (thickness 25 μm) was used. The corona-treated surface was printed with diluted coating agent 3 using a gravure printing machine equipped with a gravure plate having a plate depth of 60 μm, at a printing speed of 50 m / min and an in-line oven temperature of 60 ° C. to form a coating layer. Next, using a dry laminating machine equipped with a gravure plate having a plate depth of 40 μm, a polyether-based reactive urethane adhesive (manufactured by Toyo-Morton Co., Ltd., "TM-340V / CAT-29B") was applied to the coating layer of the substrate 1 to form an adhesive layer, and a low-density polyethylene (LLDPE) film (thickness 60 μm) was bonded to the adhesive layer as the substrate 2 to produce a laminate film. The laminate film produced as described above was stored at 40 ° C. for 1 day, and a laminate having the structure (2) (substrate 1 / coating layer / adhesive layer / substrate 2) was obtained. The thermal shrinkage of the resulting laminate was 10.9%, and the peak temperature difference of the loss tangent was 1.0°C.

[0125] [Example 22] A diluted coating agent 3 was printed on the corona-treated surface of a single-sided corona-treated low-density polyethylene (LLDPE) film (thickness 60 μm) as the substrate 2 to form a coating layer. Printing was carried out using a gravure printing machine equipped with a gravure plate with a plate depth of 60 μm, at a printing speed of 50 m / min, and in-line oven temperature of 60 °C. Next, a polyether-based reactive urethane adhesive ("TM-340V / CAT-29B" manufactured by Toyo-Morton Co., Ltd.) was applied to the coating layer of the substrate 2 using a dry laminating machine equipped with a gravure plate with a plate depth of 40 μm to form an adhesive layer. Next, a uniaxially oriented polyethylene (MDOPE) film (thickness 25 μm) was bonded to the adhesive layer as the substrate 1 to produce a laminate film. The laminate film produced as described above was stored at 40 °C for 1 day to obtain a laminate having the structure (3) (substrate 1 / adhesive layer / coating layer / substrate 2). The heat shrinkage of the resulting laminate was 12.3%, and the peak temperature difference of the loss tangent was 1.0°C.

[0126] [Comparative Example 4] A polyether-based reactive urethane adhesive ("TM-340V / CAT-29B" manufactured by Toyo-Morton Co., Ltd.) was applied to the corona-treated surface of a uniaxially oriented polyethylene (MDOPE) film (thickness 25 μm) as substrate 1 using a dry laminator equipped with a gravure plate with a plate depth of 40 μm to form an adhesive layer. Next, a low-density polyethylene (LLDPE) film (thickness 60 μm) was bonded to the adhesive layer as substrate 2 to produce a laminate film. The laminate film produced as described above was stored at 40°C for 1 day to obtain a laminate having a configuration of substrate 1 / adhesive layer / substrate 2. The obtained laminate melted under heat and pressure, making it impossible to measure the thermal shrinkage rate.

[0127] Example 30: Coating agent 24 was diluted with a mixed solvent (isopropyl alcohol / ethyl acetate) to a solids content of 15%. A uniaxially stretched polyethylene film, MDOPE2 (surface oxygen element ratio 4.0%, thickness 25 μm), corona-treated on both sides was prepared as substrate 1. The diluted coating agent 24 was printed on the corona-treated surface of substrate 1 to form a coating layer. Printing was performed using a gravure printing press equipped with a 60 μm deep gravure plate at a printing speed of 50 m / min and an in-line oven temperature of 60°C. Next, a polyether-based reactive urethane adhesive ("TM-340V / CAT-29B" manufactured by Toyo-Morton Co., Ltd.) was applied to the corona-treated surface opposite the surface on which the coating layer was formed using a dry laminating machine equipped with a 40 μm deep gravure plate to form an adhesive layer. A low-density polyethylene (LLDPE) film (thickness 60 μm) was then bonded to the adhesive layer as substrate 2 to produce a laminate film. The laminate film prepared as described above was stored at 40°C for 1 day to obtain a laminate having the structure (1) (coating layer / substrate 1 / adhesive layer / substrate 2). The thermal shrinkage of the obtained laminate was 0.1% or less, and the peak temperature difference of the loss tangent was 1.5°C.

[0128] Examples 31 to 65 Laminates were obtained in the same manner as in Example 30, except that the composition, coating agent, and printing conditions for the coating agent were changed as shown in Table 4. Details of the substrates are as follows: MDOPE: (surface oxygen element ratio 10.2%, thickness 25 μm, stretch ratio 8 times) MDOPE2: (surface oxygen element ratio 4.0%, thickness 25 μm, stretch ratio 8 times) MDOPE3: (surface oxygen element ratio 10.2%, thickness 25 μm, stretch ratio 5 times) MDOPE4: (surface oxygen element ratio 10.2%, thickness 25 μm, stretch ratio 10 times)

[0129] <Evaluation of Laminates> The laminates produced in the Examples and Comparative Examples were evaluated for heat resistance, bag-making suitability, and adhesion as follows. The results are shown in Tables 3 and 4.

[0130] [Heat Resistance] The laminate was cut into a size of 50 mm x 25 mm (when the substrate contained a uniaxially stretched film, the long side was 50 mm in the stretching direction (MD direction)). The cut-out test piece was heated and pressed using a heat seal tester. Figures 1 and 2 are plan views illustrating a method for measuring the shrinkage rate of a laminate during heating and pressing. As shown in Figure 1, a laminate cut into a size of 50 mm x 25 mm was heated and pressed in an area of ​​20 mm x 10 mm. The area (S1) before heating and pressing is the same as the heated and pressed area (A). In contrast, Figure 2 shows the area (S2) after heating and pressing, where the end (25 mm side on the heated and pressed side) D1 before heating and pressing has become end D2 due to thermal shrinkage. The heating and pressing conditions were as follows. Next, the change in appearance of the laminate was evaluated according to the following evaluation criteria. <Heating and pressing conditions> Heating temperature: 160°C, pressure: 2 kg / cm ２ , Heating and pressing time: 1 second, Heating and pressing direction: Heating and pressing was applied from the coating layer side of the laminate. For Examples 21 and 22 where the coating layer was not the outermost layer, heating and pressing was applied from the substrate 1 side. (Evaluation criteria) S: No noticeable wrinkles occurred in the heated and pressed area. (Very good) A: Wrinkles occurred in the heated and pressed area, but there were no areas where the film had melted. (Good) B: Wrinkles occurred in the heated and pressed area, and there were areas where the film had melted. (Usable) C: The heated and pressed area was completely melted and separated. (Unusable)

[0131] [Bag Forming Suitability] A laminate measuring 30 m in length and 12.5 cm in width was marked every 1 m, and heated and pressurized 30 times per 1 m in length using a three-side seal automatic bag making machine under the following conditions. The shrinkage rate in the longitudinal direction of the laminate was then evaluated according to the following evaluation criteria. <Heat and pressurization conditions> Heating temperature: 145°C, pressure: 2 kg / cm ２, Heating and pressing time: 1 second. Heating and pressing direction: Heating and pressing was applied from the coating layer side of the laminate. For Examples 21 and 22, in which the coating layer was not the outermost layer, heating and pressing was applied from the substrate 1 side. (Evaluation criteria) S: Shrinkage rate in the length direction is less than 2.5%. (Very good) A: Shrinkage rate in the length direction is 2.5% or more and less than 5%. (Good) B: Shrinkage rate in the length direction is 5% or more and less than 10%. (Usable) C: Shrinkage rate in the length direction is 10% or more, or the film has melted (Unusable)

[0132] [Adhesion] An adhesion test was conducted on the laminate by a cross-cut method in accordance with JIS K5600-5-6. The adhesion was then evaluated according to the following evaluation criteria. (Evaluation criteria) S: The result of the adhesion test was category 0 to 1. That is, the peeled area was less than 5%. A: The result of the adhesion test was category 2. That is, the peeled area was 5% or more and less than 15%. B: The result of the adhesion test was category 3. That is, the peeled area was 15% or more and less than 35%. C: The result of the adhesion test was category 4 to 5. That is, the peeled area was 35% or more.

[0133] The laminates produced in Examples 30 to 65 were evaluated as follows. The results are shown in Table 4. [Colorability after heating] The substrate 2 side of the obtained laminate was attached to a metal plate and heated at 200°C for 15 minutes, and the color change ΔE of the laminate before and after heating was evaluated. The color change ΔE was calculated using the following formula, based on the color values ​​L*x, a*x, and b*x measured from the substrate 1 side of the laminate using a spectrophotometer (X-rite eXact, manufactured by X-rite Corporation). (Formula 4) ΔE=((L*x-L*y) ２ +(a*x-a*y) ２ +(b*x-b*y) ２ ) １／２ (Evaluation criteria) S: Color change ΔE before and after heating is less than 10. A: Color change ΔE before and after heating is 10 or more and less than 20. B: Color change ΔE before and after heating is 20 or more and less than 30. C: Color change ΔE before and after heating is 30 or more.

[0134] [HSP Difference Between Two Resins] The Hansen Solubility Parameter (HSP) is an index showing the solubility of a substance, and is expressed by the dispersion term δd, the polar term δp, and the hydrogen bonding term δh. The HSP difference (Ra) between two substances is calculated from the difference Δδd in the dispersion term between the two substances, the difference Δδp in the polar term, and the difference Δδh in the hydrogen bonding term, as follows: Ra = {4 × Δδd ２ +Δδp ２ +Δδh ２} １／２ The Hansen solubility parameter is expressed as follows: a smaller Ra indicates higher compatibility, and a larger Ra indicates lower compatibility. The Hansen solubility parameters were referenced to the values ​​described in "Hansen Solubility Parameters; A User's Handbook" by Charles M. Hansen (CRC Press, 2007). For substances for which literature values ​​are unknown, values ​​calculated using solubility tests of the substance in multiple solvents and known computer software such as Hansen Solubility Parameters in Practice (HSPiP) were referenced.

[0135] [HSP Difference Between Resin (B) and Substrate 1] With regard to the HSP difference between Resin (B) and Substrate 1, the following HSP values ​​were used for Substrate 1: Polyethylene substrate (MDOPE, MDOPE2, MDOPE3, MDOPE4, LLDPE) δd: 16.9, δp: 0.8, δh: 2.8 Polypropylene substrate (OPP) δd: 18.0, δp: 0, δh: 1.0

[0136]

[0137]

[0138]

[0139] As shown in Table 3, Comparative Examples 1, 3, and 5 were laminates that did not satisfy the requirement of a shrinkage rate of 30% by area or less, and melt-cut when pressurized, resulting in poor heat resistance and suitability for bag formation. Comparative Example 2 was a laminate with a shrinkage rate of more than 30% by area, and had poor suitability for bag formation and adhesion. Comparative Example 4 was a laminate without a coating layer, and had poor heat resistance and suitability for bag formation. On the other hand, the Examples were laminates that had a coating layer containing a resin with a Tg of 115°C or higher, had a shrinkage rate of 30% by area or less when heated and pressurized, and had good heat resistance, suitability for bag formation, and adhesion.

[0140]

[0141]

[0142]

[0143] As shown in Table 4, the laminates of Examples 30 to 63, which are embodiments of the present invention, have a coating layer containing a resin with a glass transition temperature of 115°C or higher. The shrinkage rate of the laminates upon heating and pressurization was 30% or less by area, and therefore, the heat resistance, bag-making suitability, and adhesion were all excellent. Furthermore, the colorability after heating was also excellent, which facilitates improving recyclability. The laminates of Examples 30, 31, and 62 were each cut into 50 mm x 25 mm pieces (when the substrate contained a uniaxially stretched film, the short side was 25 mm in the stretching direction (MD direction)). Thermal shrinkage was evaluated. Specifically, the laminates were placed in a heat-sealing tester, with the stretching direction changed between vertical and horizontal directions, and heated and pressurized within a 20 mm x 10 mm area as shown in Figures 1 and 2, to evaluate the thermal shrinkage rate of the laminates. The thermal shrinkage rates of the laminates of Examples 30, 31, and 62, measured by the above method, were similar to the results evaluated by the method described for measuring heat resistance. This shows that the same heat shrinkage rate is obtained when heated and pressurized in both the MD and TD directions. Furthermore, not only in Example 60, which uses an unstretched substrate, but also in Examples 58 and 59, which have different substrate stretch ratios, the desired properties can be obtained by achieving a heat shrinkage rate of 30 area % or less for the laminate. Furthermore, it can be seen that the desired properties can be more easily improved by adjusting the composition and amount of the coating agent that forms the coating layer and the amount of surface treatment of the substrate. Explanation of symbols

[0144] 10 Laminate A Area to be heated and pressed S1 Area before heating and pressing S2 Area after heating and pressing D1 Edge before heating and pressing (25 mm side) D2 Edge after heating and pressing (25 mm side)

Claims

1. A laminate comprising a base material 1, an adhesive layer, and a base material 2 in this order, and further having a coating layer, The base material 1 and the base material 2 contain a polyolefin resin, The coating layer comprises a resin (A) having a glass transition temperature of 115°C or higher. A laminate in which the shrinkage rate expressed by the following formula (Equation 1) is 30 area % or less when heated and pressurized under the following heating and pressurizing conditions. (Heating and pressurizing conditions) Heating temperature: 145°C, pressurization: 2 kg / cm² ２ Heating and pressurizing time: 1 second (Formula 1) Shrinkage rate (area %) = {1 - (area after heating and pressurizing) / (area before heating and pressurizing)} × 100

2. A laminate having a coating layer and a substrate 1, The base material 1 contains polyethylene resin, The coating layer comprises a resin (A) having a glass transition temperature of 115°C or higher. A laminate in which the shrinkage rate expressed by the following formula (Equation 1) is 30 area % or less when heated and pressurized under the following heating and pressurizing conditions. (Heating and pressurizing conditions) Heating temperature: 145°C, pressurization: 2 kg / cm² ２ Heating and pressurizing time: 1 second (Formula 1) Shrinkage rate (area %) = {1 - (area after heating and pressurizing) / (area before heating and pressurizing)} × 100

3. The laminate according to claim 1, wherein the polyolefin resin is polyethylene resin.

4. The laminate according to claim 1 or 2, wherein the difference between the peak temperature of the loss tangent (tanδ) of the laminate and the peak temperature of the tanδ of the laminate excluding the coating layer, measured between 80°C and 170°C according to JIS K 7244, is 1.0°C or more.

5. The laminate according to claim 1 or 2, wherein the resin (A) includes a resin having a ring structure.

6. The laminate according to claim 1 or 2, wherein the coating layer further comprises a chlorinated polyolefin resin.

7. The laminate according to claim 1 or 2, wherein the coating layer further comprises particles.

8. A method for manufacturing a laminate having a base material 1, an adhesive layer, and a base material 2 in that order, and further having a coating layer, A step of forming a coating layer by printing a coating agent containing a resin (A) having a glass transition temperature of 115°C or higher onto one surface of a substrate 1, The process of printing an adhesive onto the other surface of the substrate 1 or onto the coating layer to form an adhesive layer, The process of bonding the substrate 2 onto the adhesive layer and It has, A method for manufacturing a laminate, wherein the shrinkage rate of the laminate, when heated and pressurized under the following heating and pressurizing conditions, is 30 area % or less, as expressed by the following formula (1). (Heating and pressurizing conditions) Heating temperature: 145°C, pressurization: 2 kg / cm² ２ Heating and pressurizing time: 1 second (Formula 1) Shrinkage rate (area %) = {1 - (area after heating and pressurizing) / (area before heating and pressurizing)} × 100

9. The laminate according to claim 1 or 2, which is for use in gusseted bags or stand-up pouches.

10. A packaging material constructed using the laminate described in claim 1 or 2.

11. A coating agent used to form the coating layer of a laminate comprising a base material 1, an adhesive layer, and a base material 2 in that order, and further comprising a coating layer, wherein the base material 1 and the base material 2 contain a polyolefin resin, A resin (A) having a glass transition temperature of 115°C or higher, and a solvent are included. A coating agent wherein the resin (A) contains 55% by mass or more of a resin having a ring structure, based on the total mass of the resin (A).

12. The coating agent according to claim 11, wherein the resin having the ring structure includes a cellulose-based resin.

13. The coating agent according to claim 11 or 12, further comprising inorganic particles, wherein the inorganic particles comprise one or more selected from the group consisting of calcium carbonate, barium sulfate, and zinc oxide.