Packaging material for tube container, tube container and method for manufacturing resin pellet

Abstract

To provide a packaging material for a tube container, a tube container and a method for manufacturing a resin pellet, which can reduce environmental loads.SOLUTION: A packaging material 10 for a tube container includes a first sealant layer 11, a peeling layer 12, and a second sealant layer 13, which are arranged in order from an outer surface 101 to an inner surface 102. At least 90% or more of the first sealant layer 11 is the same resin-based material. The peeling layer 12 is composed of a material whose adhesive force is lowered due to heating or light exposure.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a packaging material for tube containers, a tube container, and a method for producing resin pellets. [Background technology]

[0002] Conventionally, tubular containers including aluminum foil have been known (for example, Patent Document 1). Patent Document 1 discloses a tubular container that can suppress the occurrence of wrinkles in the aluminum foil layer at the side seam portion when the side seam is made into a cylindrical body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-187819 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, such tube containers containing aluminum foil are generally incinerated without recycling the resin.

[0005] On the other hand, in recent years, there has been an increasing demand for the creation of a recycling-oriented society, and therefore, there is a demand for reducing the environmental load by recycling resins from tube containers by various methods.

[0006] The present disclosure has been made in consideration of these points, and aims to provide a packaging material for tube containers, a tube container, and a method for producing resin pellets that are capable of reducing the environmental impact. [Means for solving the problem]

[0007] The embodiments of the present disclosure relate to the following [1] to [6].

[0008] [1] The sealant includes a first sealant layer, a release layer, and a second sealant layer, which are arranged in this order from the outer surface to the inner surface, At least 90% of the first sealant layer is made of the same resin-based material; The packaging material for tube containers, wherein the release layer is made of a material whose adhesive strength decreases when heated or exposed to light.

[0009] [2] The packaging material for tube containers according to [1], wherein the second sealant layer contains a material of the same resin system.

[0010] [3] The packaging material for tube containers according to [1] or [2], further comprising a base material layer provided between the release layer and the second sealant layer.

[0011] [4] The packaging material for tube containers according to any one of [1] to [3], further comprising a barrier layer provided between the release layer and the second sealant layer.

[0012] [5] The packaging material for tube containers according to any one of [1] to [4], wherein at least one of the first sealant layer and the second sealant layer contains a biomass-derived resin.

[0013] [6] In a tube container, [1] to [5], and a body tube having the packaging material for a tube container according to any one of the above. a head member joined to one end of the body tube.

[0014] [7] A method for producing resin pellets, comprising the steps of: A step of recovering the packaging material for tube containers according to any one of [1] to [5] or the tube container according to [6]; A step of crushing the collected tube container packaging material or the tube container; a step of removing foreign matter from the crushed tube container packaging material or the crushed tube container by stirring the crushed tube container packaging material or the crushed tube container in water; a step of heating or exposing the crushed tube container packaging material or tube container to light to reduce the adhesive strength of the peel layer, thereby separating the first sealant layer from the second sealant layer; drying and screening the first sealant layer separated from the second sealant layer; pulverizing the selected first sealant layer; Melting the pulverized first sealant layer; forming a resin pellet from the molten first sealant layer; and cooling the resin pellets. Effect of the Invention

[0015] According to the present disclosure, the environmental burden can be reduced. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a perspective view showing a resin pellet according to an embodiment. [Diagram 2] FIG. 2 is a cross-sectional view showing a packaging material for tube containers according to one embodiment. [Diagram 3] FIG. 3 is a cross-sectional view showing a packaging material for tube containers according to one embodiment. [Figure 4] FIG. 4 is a partial vertical cross-sectional view showing a tube container according to one embodiment. [Diagram 5] FIG. 5 is a flow chart illustrating a recycling method and a method for producing resin pellets according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] An embodiment will be described below with reference to the drawings. FIGS. 1 to 5 are diagrams showing an embodiment. Each of the figures shown below is a schematic diagram. Therefore, the size and shape of each part are appropriately exaggerated to facilitate understanding. In addition, the present invention can be modified appropriately within the scope of the technical concept. In each of the figures shown below, the same parts are given the same reference numerals, and some detailed explanations may be omitted. In addition, the numerical values ​​such as the dimensions of each member and the material names described in this specification are examples of an embodiment, and are not limited to these and can be appropriately selected and used. In this specification, terms that specify shapes and geometric conditions, such as parallel, orthogonal, and vertical, are interpreted to include substantially the same state in addition to their strict meanings.

[0018] First, with reference to FIG. 1, the structure of a resin pellet 1 produced by the recycling method and the method for producing resin pellets according to the present embodiment will be described.

[0019] <Resin pellets> As shown in Fig. 1, the resin pellet 1 is a resin lump with a maximum width of about 1 mm to 7 mm. In the illustrated example, the resin pellet 1 has a cylindrical shape. Although not shown, the resin pellet 1 may have a spherical shape. The resin pellet 1 is a resin lump produced by cutting extruded resin (strands) extruded in a string shape from a filter into granules in a pellet production device (not shown).

[0020] The resin pellets 1 contain recycled resin (hereinafter, simply referred to as recycled resin). This can reduce the environmental impact of the tube container packaging material 10 and the like produced from the resin pellets 1. In this specification, the term "recycled resin" refers to a resin material obtained by removing foreign matter and dirt from a resin body. The resin body may be a resin product used in the market (a tube container 40 described later), or a material generated in a resin product manufacturing process before it is released to the market (a tube container packaging material 10 described later). In other words, the recycled resin may be a resin obtained by post-consumer recycling (PCR), or may be a resin obtained by post-industrial recycling (PIR). In addition, when the recycled resin is produced by post-consumer recycling (PCR), the recycled resin may be a resin recycled from another tube container 40 produced from the resin pellets 1.

[0021] When obtaining recycled resin, first, a resin body (a tube container packaging material 10 or a tube container 40 described later) is selected and crushed. Then, foreign matter is removed from the crushed resin body. As a result, flakes from which foreign matter has been removed are obtained. At this time, if necessary, the crushed resin body may be washed with water, hot water, a surfactant, an alkaline cleaning solution, or the like to remove dirt adhering to the flakes. In this case, for example, an aqueous solution of a mixture of a surfactant and an alkaline cleaning solution may be heated to about 80°C, and the crushed resin body may be washed with the aqueous solution. Then, the flakes are further treated at high temperature and reduced pressure for a certain period of time to obtain a resin material from which foreign matter and dirt have been removed (i.e., recycled resin).

[0022] In this embodiment, at least 90% or more of the recycled resin is a material of the same resin system. In this case, the recycled resin can be classified as a so-called mono-material material, and can be suitably used for manufacturing a packaging container (so-called mono-material packaging container) made of the same material. In addition, the recycled resin (resin pellets 1) is made from a mono-material material (a packaging material 10 for a tube container described later) or a mono-material packaging container (a tube container 40 described later). This makes it possible to easily increase the content of the material of the same resin system in the recycled resin (resin pellets 1). The material constituting the recycled resin may be polyolefin. Specifically, the material constituting the recycled resin may be polyethylene or polypropylene. In other words, the resin pellets 1 may contain polyethylene or polypropylene as a main component.

[0023] Here, for example, polyethylene includes high-density polyethylene and linear low-density polyethylene. These high-density polyethylene and linear low-density polyethylene are classified as "materials of the same resin system" in this specification. On the other hand, for example, polyethylene and polyester are not classified as materials of the same resin system.

[0024] The resin pellets 1 may further contain an ethylene-vinyl alcohol copolymer (EVOH). In a packaging material for a tube container constituting the body tube of a tube container, a layer containing an ethylene-vinyl alcohol copolymer may be provided as a barrier layer. Therefore, when the resin pellets 1 are produced from such a tube container, the resin pellets 1 contain an ethylene-vinyl alcohol copolymer. In this case, the content of the ethylene-vinyl alcohol copolymer in the resin pellets 1 may be 5% by weight or less.

[0025] Furthermore, the resin pellets 1 may further contain metal particles. In the packaging material for a tube container constituting the body tube of the tube container, a metal foil (e.g., aluminum foil, etc.) or a vapor-deposited film of a metal (e.g., aluminum, etc.) may be provided as a barrier layer. Therefore, when the resin pellets 1 are produced from such a tube container, the resin pellets 1 contain metal particles. In this case, the content of the metal particles in the resin pellets 1 may be 1% by weight or less.

[0026] The resin pellets 1 may be produced by a so-called hot cut method in which the molten resin is cut in a molten state without being cooled. Alternatively, the resin pellets 1 may be produced by a so-called cold cut method in which the molten resin is cut after being cooled. When cooling the molten resin in this way, a cooling method such as a water cooling method in which water is directly poured onto the molten resin, a mist cooling method in which water is turned into a mist and poured onto the molten resin, or an air cooling method in which air is blown onto the molten resin may be used.

[0027] Next, the tube container packaging material 10 according to this embodiment will be described.

[0028] <Packaging material for tube containers> 2 and 3, the tube container packaging material 10 includes a first sealant layer 11, a peelable layer 12, and a second sealant layer 13, which are arranged in this order from an outer surface 101 to an inner surface 102. The tube container packaging material 10 may further include a base layer 14 provided between the peelable layer 12 and the second sealant layer 13. The tube container packaging material 10 may further include a barrier layer 15 provided between the peelable layer 12 and the second sealant layer 13.

[0029] Specifically, as shown in Fig. 2, the tube container packaging material 10 includes, in this order from an outer surface 101 to an inner surface 102, a first sealant layer 11, a peel layer 12, a base layer 14, a printed layer 17, a first adhesive layer 16a, a barrier layer 15, a second adhesive layer 16b, and a second sealant layer 13. In the tube container packaging material 10 shown in Fig. 2, the first sealant layer 11 constitutes the outer surface 101 of the tube container packaging material 10, and the second sealant layer 13 constitutes the inner surface 102 of the tube container packaging material 10.

[0030] 3, the tube container packaging material 10 includes, in this order from the outer surface 101 to the inner surface 102, a first sealant layer 11, a peel layer 12, a base layer 14, a printed layer 17, a first adhesive layer 16a, a barrier layer 15, an intermediate layer 18, a second adhesive layer 16b, and a second sealant layer 13. In the tube container packaging material 10 shown in FIG. 3, the first sealant layer 11 forms the outer surface 101 of the tube container packaging material 10, and the second sealant layer 13 forms the inner surface 102 of the tube container packaging material 10.

[0031] Each layer of the tube container packaging material 10 will be described below.

[0032] <<First sealant layer>> The first sealant layer 11 is a layer for bonding together the tube container packaging materials 10. This first sealant layer 11 is a layer that becomes the outermost layer when a tube container 40, which will be described later, is produced from the tube container packaging material 10.

[0033] In this embodiment, at least 90% or more of the first sealant layer 11 is made of the same resin material. This makes it possible to increase the content of the same resin material in the recycled resin (resin pellets 1) produced from the tube container 40 when the tube container 40 described later is recycled.

[0034] The material constituting the first sealant layer 11 may be a material that melts and fuses by heat. In this case, the material constituting the first sealant layer 11 is a material of the same resin system as the material constituting the second sealant layer 13. The first sealant layer 11 may be made of, for example, polyolefin. More specifically, the first sealant layer 11 may be made of, for example, one or more resins such as acid-modified polyolefin resins obtained by modifying polyolefin resins such as low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), polypropylene, polyethylene, or polypropylene with acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, or other unsaturated carboxylic acids, polyvinyl acetate resins, polyester resins, polystyrene resins, polyacrylonitrile, saturated polyesters, or polyvinyl alcohol.

[0035] The first sealant layer 11 may contain a resin derived from biomass. For example, when the first sealant layer 11 contains polyethylene or polypropylene, the polyethylene may be biomass polyethylene, and the polypropylene may be biomass polypropylene. Since the first sealant layer 11 contains a resin derived from biomass, the amount of fossil fuel used can be reduced, and the environmental impact of the packaging material 10 for tube containers can be reduced. Note that biomass polyethylene is a monomer polymer containing ethylene derived from biomass. Since ethylene derived from biomass is used as the raw material monomer, the polyolefin obtained by polymerization is derived from biomass. The content of ethylene derived from biomass in the raw material monomer does not need to be 100% by mass, and is, for example, preferably 50% or more, more preferably 80% or more. The raw material monomer may contain ethylene derived from fossil fuel, and may contain α-olefin monomers such as butylene, hexene, and octene.

[0036] For example, biomass-derived ethylene can be produced using biomass-derived ethanol as a raw material. In particular, it is preferable to use biomass-derived fermented ethanol obtained from a plant raw material. The plant raw material is not particularly limited, and any conventionally known plant can be used. Examples of conventionally known plants include corn, sugarcane, beet, and manioc.

[0037] The first sealant layer 11 may also be composed of a film made from the above-mentioned resin pellets 1. In this case, the film may be made, for example, by using the resin pellets 1 and an inflation method or other molding method. The film made from the resin pellets 1 may contain recycled resin, and at least 90% of the recycled resin may be a material of the same resin system.

[0038] The film made from the above-mentioned resin pellets 1 may further contain an ethylene-vinyl alcohol copolymer. In this case, the content of the ethylene-vinyl alcohol copolymer in the film may be 5% by weight or less.

[0039] The film may further contain metal particles. In this case, the content of the metal particles in the film may be 1% by weight or less.

[0040] Furthermore, the film may further contain virgin resin. Note that "virgin resin" refers to a resin material that has not been subjected to a recycling process. By containing virgin resin in the film in this way, the hygiene of the film can be improved.

[0041] The material for the first sealant layer 11 may be a material to which, for example, an antiblocking agent, a lubricant (fatty acid amide, etc.), a flame retardant, an inorganic or organic filler, etc. are optionally added.

[0042] In the present embodiment, the thickness of the first sealant layer 11 is preferably not less than 50 μm and not more than 250 μm.

[0043] <<Release layer>> The release layer 12 is a layer for peeling the first sealant layer 11 and the second sealant layer 13 from each other. The release layer 12 is made of a material whose adhesive strength decreases when heated or exposed to light. In other words, the release layer 12 is made of a material whose adhesive strength decreases or disappears when heated or exposed to light. In this case, the release layer 12 may be made of a material that foams and peels off when heated or exposed to light.

[0044] The material that foams and peels off when heated may be a material in which thermally expandable microcapsules are added to an adhesive or bonding agent. Thermally expandable microcapsules are capsules that contain a foaming component (hydrocarbon) inside an acrylic resin. When heated, the acrylic resin, which is the outer shell resin, softens, and the pressure of the foaming component increases, causing a sudden volume expansion. The heating temperature may be 120°C or higher and 265°C or lower.

[0045] In this case, the adhesive or bonding agent may be, for example, an anchor coating agent such as an isocyanate (urethane), polyethyleneimine, polybutadiene, or organic titanium. In addition, the adhesive or bonding agent may be, for example, a polyurethane, polyacrylic, polyester, epoxy, polyvinyl acetate, cellulose, or other laminating adhesive.

[0046] In addition, materials that can be suitably used to form the pressure-sensitive adhesive or bonding agent include, for example, polyethylene, polypropylene, ethylene-vinyl alcohol, ethylene-methacrylic acid copolymer (EMAA), ethylene-acrylic acid copolymer, ionomer, or maleic anhydride-modified polyolefin resin.

[0047] The release layer 12 may have an initial adhesive strength before heating, that is, a peel strength to the first sealant layer 11 at a peel speed of 300 mm / min and a peel angle of 180 degrees of 5 N / 25 mm or more and 25 N / 25 mm or less.

[0048] Furthermore, the peeling layer 12 may have an adhesive strength after heating of 0 N / 25 mm or more and 1.0 N / 25 mm or less with respect to the first sealant layer 11 at a peeling speed of 300 mm / min and a peeling angle of 180 degrees.

[0049] Next, materials that foam and peel when exposed to light will be described. In the following description, (meth)acrylic means either acrylic or methacrylic, and (meth)acrylate means either acrylate or methacrylate. In addition, in the present disclosure, "light" includes light including ultraviolet light.

[0050] When the release layer 12 is made of a material that foams and peels off when exposed to light, the material that constitutes the release layer 12 is represented by at least one of the following general formulas (1) and (2), has a maximum molar absorption coefficient of 7000 or more in the wavelength range of 240 nm or more and 450 nm or less, and may contain a gas generating agent that generates gas when irradiated with light.

[0051] [ka] In the general formulas (1) and (2), each A independently represents a gas-generating moiety represented by the following general formula (A-1), (A-2) or (A-3); each L independently represents a direct bond or a divalent linking group; 1 represents a monovalent fluorinated aliphatic hydrocarbon group or a monovalent organopolysiloxane group which has 2 to 8 carbon atoms directly bonded to fluorine atoms and which may contain an ether bond (-O-) in the carbon chain and which may have a substituent; Q 2 represents a divalent fluorinated aliphatic hydrocarbon group having 2 to 8 carbon atoms directly bonded to fluorine atoms and which may contain an ether bond (-O-) in the carbon chain, or a divalent organopolysiloxane group.

[0052] [ka] (In the general formulas (A-1), (A-2) and (A-3), R 1 represents an aromatic group having 3 to 20 carbon atoms which may have a substituent; R 2 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent; R 3 each independently represents a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, a cyano group, -COOR 5 , or -CONR 6 R 7 , R 4 represents a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, a cyano group, -COOR 5 , -CONR 6 R 7 , or the above-LQ 1 R 5 and R 7 each independently represents a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent; R 6 represents a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms.

[0053] The gas generating agent of the present disclosure has a gas generating part having the specific structure and the specific fluorinated aliphatic hydrocarbon group or the specific organopolysiloxane group. The gas generating agent of the present disclosure has a maximum molar absorption coefficient of 7000 or more at a wavelength of 240 nm or more and 450 nm or less. The gas generating agent of the present disclosure generates gas by light irradiation, thereby improving the effect of imparting peelability to a surface.

[0054] The reason why the gas generating agent of the present disclosure can improve the effect of imparting releasability to a surface is not clear, but is presumed to be as follows.

[0055] In the release layer 12 containing a gas generating agent for the purpose of high adhesion and easy peeling, by irradiating light after use, the gas generated from the gas generating agent is released to the surface of the release layer 12, i.e., the interface with the adherend, and at least a part of the adherend is peeled off by the pressure. By releasing the gas to the surface of the release layer 12, the contact area of ​​the release layer 12 with the adherend is reduced, making it easy to peel off. In the release layer 12 containing a conventional gas generating agent, since the gas generating agent is uniformly dispersed in the release layer 12, even when light is irradiated, the gas is difficult to be released from the gas generating agent present inside the release layer 12 to the surface of the release layer 12. As a result, the amount of gas generated on the surface of the release layer 12 is insufficient only with the gas generated from the gas generating agent present near the surface of the release layer 12. For this reason, the reduction in peeling force is insufficient, and the ease of peeling is insufficient. Furthermore, if the content of the gas generating agent in the release layer 12 is increased in order to increase the amount of gas generated on the surface of the release layer 12, there is a possibility that the adhesive strength of the release layer 12 will decrease or that the release layer 12 will become cloudy. For this reason, there is a limit to the improvement in release strength by adding a gas generating agent.

[0056] In contrast, the gas generating agent of the present disclosure is likely to be localized on the surface because the specific fluorinated aliphatic hydrocarbon group or the specific organopolysiloxane group is introduced into the gas generating portion having the specific structure. In the release layer 12 containing the gas generating agent of the present disclosure, the gas generating agent is likely to be localized on the surface of the release layer 12, so that when light is irradiated, the gas generating agent localized on the surface of the release layer 12 generates gas, and the gas is likely to be released to the surface of the release layer 12. In the release layer 12 containing the gas generating agent of the present disclosure, the amount of gas generated on the surface of the release layer 12 is efficiently increased, so that the release layer 12 has excellent ease of peeling from the adherend. Since the gas generating agent of the present disclosure is likely to be localized on the surface of the release layer 12, the amount of gas generated on the surface of the release layer 12 can be efficiently increased without increasing the content of the gas generating agent. Therefore, the adhesive strength of the release layer 12 can be suppressed from decreasing and the clouding can be suppressed. In this way, it is presumed that the gas generating agent of the present disclosure can improve the effect of imparting peelability to the surface.

[0057] The gas generating agent of the present disclosure can generate gas by decomposing when irradiated with light. The gas generating agent of the present disclosure has a maximum molar absorption coefficient of 7000 or more at a wavelength of 240 nm or more and 450 nm or less, and can efficiently absorb light including ultraviolet light, and can efficiently decompose when irradiated with light including ultraviolet light to generate gas. In the above general formulas (1) and (2), A each independently represents a gas-generating moiety represented by the general formula (A-1), (A-2) or (A-3). The gas-generating moiety represented by the general formula (A-1) generates nitrogen gas by decomposing the tetrazole ring upon light irradiation. The gas-generating moiety represented by the general formula (A-2) generates nitrogen gas by decomposing the -(C=O)-(C=N2)- bond into a -(C=C=O)- bond and nitrogen gas upon light irradiation. The gas-generating moiety represented by the general formula (A-3) generates nitrogen gas by decomposing the azo group portion upon light irradiation.

[0058] In general formula (A-1), R 1 The aromatic group having 3 to 20 carbon atoms, which may have a substituent, may be appropriately selected so that the compound satisfies the maximum value of the specific molar absorption coefficient. Examples of the aromatic group having 3 to 20 carbon atoms include an aromatic hydrocarbon group and an aromatic heterocyclic group.

[0059] Examples of the aromatic hydrocarbon group include aromatic hydrocarbon groups having 6 to 20 carbon atoms, and preferably aromatic hydrocarbon groups having 6 to 12 carbon atoms. Examples of the aromatic hydrocarbon group include a phenyl group, a biphenyl group, a naphthyl group, an anthryl group, a phenanthryl group, a fluorenyl group, a naphthylphenyl group, and a pyrenyl group.

[0060] Examples of the aromatic heterocyclic group include aromatic heterocyclic groups having 3 to 20 carbon atoms containing at least one of a nitrogen atom, an oxygen atom, and a sulfur atom, and are preferably aromatic heterocyclic groups having 3 to 10 carbon atoms. Examples of the aromatic heterocyclic group include a pyrrolyl group, a furyl group, a thienyl group, a pyrazolyl group, an imidazolyl group, an oxazolyl group, an isoxazolyl group, a thiazolyl group, an isothiazolyl group, and a carbazole group.

[0061] Examples of the substituent that the aromatic group may have include halogen atoms such as F, Cl, and Br, nitro groups, alkyl groups, alkenyl groups, aralkyl groups, alkoxy groups such as methoxy groups, tertiary amino groups such as diphenylamino groups, and acyl groups such as benzoyl groups. The alkyl groups, alkenyl groups, and aralkyl groups may be the same as the alkyl groups having 1 to 20 carbon atoms, alkenyl groups having 2 to 20 carbon atoms, and aralkyl groups described below, but are preferably alkyl groups having 1 to 14 carbon atoms, alkenyl groups having 2 to 14 carbon atoms, and aralkyl groups having 7 to 14 carbon atoms. By appropriately selecting the substituents of the aromatic group, it is possible to change the light absorption wavelength or improve compatibility with other components. Examples of the substituents that change the light absorption wavelength to the long wavelength side include alkoxy groups such as methoxy groups, diarylamino groups such as diphenylamino groups, and acyl groups such as benzoyl groups.

[0062] R 1 As the aromatic hydrocarbon group, an aromatic hydrocarbon group having 6 to 14 carbon atoms which may have a substituent may be used since the absorption wavelength region can be expanded and made longer. Among these, an aromatic hydrocarbon group having 6 to 12 carbon atoms which may have a substituent is preferred, and a phenyl group, naphthyl group, or anthryl group which may have a substituent is more preferred. In the case of irradiation with light including ultraviolet light, a naphthyl group is more preferred since it provides high sensitivity and improves the efficiency of gas generation.

[0063] R 2 Examples of the hydrocarbon group having 1 to 20 carbon atoms which may have a substituent include an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an aralkyl group, and an aryl group.

[0064] The alkyl group having 1 to 20 carbon atoms may be linear, branched, or cyclic, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a 2-ethylhexyl group, a cyclopentyl group, a cyclohexyl group, a bornyl group, an isobornyl group, a dicyclopentanyl group, an adamantyl group, and a lower alkyl group-substituted adamantyl group.

[0065] The alkenyl group having 2 to 20 carbon atoms may be linear, branched, or cyclic. Examples of such alkenyl groups include vinyl, allyl, and propenyl groups. There is no limitation on the position of the double bond in the alkenyl group, but from the viewpoint of reactivity, it is preferable that the double bond is located at the terminal of the alkenyl group.

[0066] The aryl group is the same as R 1 The aromatic hydrocarbon group may be the same as the aromatic hydrocarbon group in the above, but a phenyl group, a biphenyl group, a naphthyl group, etc. are preferably used.

[0067] Examples of the aralkyl group include a benzyl group, a phenethyl group, a naphthylmethyl group, a biphenylmethyl group, etc. The aralkyl group preferably has 7 to 20 carbon atoms, and more preferably has 7 to 14 carbon atoms.

[0068] Examples of the substituent that the hydrocarbon group may have include halogen atoms such as F, Cl and Br, and a nitro group.

[0069] The substituent of the aromatic ring of the aryl group or aralkyl group may be the alkyl group.

[0070] The preferred carbon number does not include the carbon number of the substituent.

[0071] R 2 From the viewpoints of solubility in organic solvents, reactivity, and nitrogen content in one molecule, it is preferable for each of them to be a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms which may have a substituent, and all three of them may be hydrogen atoms.

[0072] R 3 , R 4 , R 5 and R 7 The hydrocarbon group having 1 to 20 carbon atoms which may have a substituent in R 2Examples of the substituent include the same hydrocarbon group having 1 to 20 carbon atoms as the optionally substituted hydrocarbon group in the above.

[0073] R 6 The hydrocarbon group having 1 to 5 carbon atoms in R 2 Among the hydrocarbon groups having 1 to 20 carbon atoms which may have a substituent in the above formula, those corresponding to the hydrocarbon groups having 1 to 5 carbon atoms can be mentioned.

[0074] R 4 -LQ in 1 may be the same as described below.

[0075] R 5 and R 7 From the viewpoints of solubility in organic solvents and the nitrogen content in one molecule, each of them is preferably a hydrocarbon group which may have a substituent having 1 to 20 carbon atoms, and more preferably a hydrocarbon group having 1 to 10 carbon atoms.

[0076] R 6 From the viewpoint of the nitrogen content in one molecule, is preferably a hydrogen atom or a methyl group, and more preferably a hydrogen atom.

[0077] R 3 From the viewpoints of solubility in organic solvents and the nitrogen content in one molecule, each of them is preferably a hydrocarbon group having 1 to 10 carbon atoms which may have a substituent, or a cyano group, more preferably a hydrocarbon group having 1 to 5 carbon atoms, and may be a methyl group or an ethyl group.

[0078] R 4 In terms of solubility in an organic solvent and localization on the surface of the release layer 12, among others, a hydrocarbon group having 1 to 10 carbon atoms which may have a substituent or the -LQ 1 It is preferable that the -LQ 1 It is more preferable that:

[0079] In the general formulas (1) and (2), A preferably represents the gas-generating moiety represented by the general formula (A-1) in terms of heat resistance and the nitrogen content in one molecule.

[0080] Examples of the gas-generating moiety represented by the general formula (A-1) are shown below, but the invention is not limited to these.

[0081] [ka]

[0082] On the other hand, in the general formulas (1) and (2), Q 1 represents a monovalent fluorinated aliphatic hydrocarbon group which has 2 to 8 carbon atoms directly bonded to fluorine atoms, which may contain an ether bond (-O-) in the carbon chain, and which may have a substituent, or a monovalent organopolysiloxane group. 2 represents a divalent fluorinated aliphatic hydrocarbon group having 2 to 8 carbon atoms directly bonded to fluorine atoms and which may contain an ether bond (-O-) in the carbon chain, or a divalent organopolysiloxane group.

[0083] Q 1 and Q 2 In the above formula, the fluorinated aliphatic hydrocarbon group may be a linear or branched, saturated or unsaturated fluorinated aliphatic hydrocarbon group.

[0084] Q 1 and Q 2 In the above, the fluorinated aliphatic hydrocarbon group may contain carbon atoms to which no fluorine atom is directly bonded, as long as the number of carbon atoms to which fluorine atoms are directly bonded is 2 to 8. For example, when the fluorinated aliphatic hydrocarbon group contains an alkynyl group, the fluorinated aliphatic hydrocarbon group contains carbon atoms to which no fluorine atom is directly bonded.

[0085] Q 1 and Q 2In the fluorinated aliphatic hydrocarbon group in the above, not all of the carbon atoms directly bonded to fluorine atoms may be substituted with fluorine atoms, and a portion of the carbon atoms may contain hydrogen atoms or substituents. Examples of the substituents include reactive groups used for connecting to a gas generating part, such as a hydroxyl group, an amino group, a carboxyl group, or a (meth)acryloyloxy group, a vinyl ether group, a phosphate group, and an epoxy group.

[0086] Q 1 and Q 2 In terms of the effect of surface localization, the fluorine atoms in the fluorinated aliphatic hydrocarbon group in the above formula (I) are preferably 4 or more, and more preferably 6 or more. The number of fluorine atoms in the fluorinated aliphatic hydrocarbon group may be 17 or less, or may be 16 or less.

[0087] Q 1 and Q 2 As for the fluorinated aliphatic hydrocarbons in the 1 represents any one of the monovalent fluorinated aliphatic hydrocarbon groups represented by the following (Rf-1) to (Rf-5), and Q 2 is a divalent fluorinated aliphatic hydrocarbon group represented by the following (Rf-6).

[0088] [ka] (In formula (Rf-1), formula (Rf-2), and formula (Rf-3), n each independently represents an integer of 2 to 8. In formula (Rf-4), n' represents an integer of 4 to 10. In formula (Rf-5), n represents an integer of 1 to 8, n" represents an integer of 0 to 7, and m represents an integer of 0 to 7, with the proviso that n+n"×m represents an integer of 2 to 8; J 1 represents a hydrogen atom, a fluorine atom, a hydroxyl group, an amino group, a carboxy group, or a (meth)acryloyloxy group. In (Rf-6), n is an integer of 0 to 8, n" is an integer of 0 to 4, and m is an integer of 0 to 8, with the proviso that n+n"×m is an integer of 2 to 8.

[0089] In the formulae (Rf-1), (Rf-2) and (Rf-3), n each independently represents an integer of 2 to 8. From the viewpoint of the effect of surface localization, it is preferable that n represents an integer of 4 to 8.

[0090] In the above (Rf-4), n' represents an integer of 4 to 10, and from the viewpoint of the effect of surface localization, it is particularly preferable that n represents an integer of 5 to 10.

[0091] In the above (Rf-5), n is an integer of 1 to 8, n" is an integer of 0 to 7, and m is an integer of 0 to 7, provided that n+n"×m is an integer of 2 to 8. From the viewpoint of the effect of surface localization, it is preferable that n is an integer of 2 to 8, n" is an integer of 1 to 7, and m is an integer of 1 to 7, and it is particularly preferable that n+n"×m is an integer of 3 to 8.

[0092] In the above (Rf-6), n is an integer of 0 to 8, n" is an integer of 0 to 4, and m is an integer of 0 to 8, with the proviso that n+n"×m is an integer of 2 to 8. From the viewpoint of the effect of surface localization, it is preferable that n is an integer of 2 to 8, n" is an integer of 1 to 7, and m is an integer of 1 to 7, and it is particularly preferable that n+n"×m is an integer of 3 to 8.

[0093] In the above (Rf-5), J 1 represents a hydrogen atom, a fluorine atom, a hydroxyl group, an amino group, a carboxyl group, or a (meth)acryloyloxy group. 1 is preferably a hydrogen atom or a fluorine atom, more preferably a fluorine atom, but may also be a hydroxyl group, an amino group, a carboxy group, or a (meth)acryloyloxy group. 1 When the compound has such a reactive group, it may be used, for example, to bond other components in the release layer 12 to the gas generating agent.

[0094] When preparing the compound of general formula (2), even if a gas-generating moiety is not introduced to both ends but is introduced to only one end, the compound may have the structure of general formula (1) and may have a reactive group such as a hydroxyl group, an amino group, a carboxyl group, or a (meth)acryloyloxy group at the end.

[0095] Q 1 is preferably any one of the monovalent fluorinated aliphatic hydrocarbon groups represented by (Rf-1) or (Rf-5) above, more preferably any one of the monovalent fluorinated aliphatic hydrocarbon groups represented by (Rf-1) or (Rf-5) above, and even more preferably any one of the monovalent fluorinated aliphatic hydrocarbon groups represented by (Rf-1) above.

[0096] On the other hand, Q 1 and Q 2 In the above, the organopolysiloxane group is a siloxane bond -(O-Si) a - (where a is the number of repetitions) in the main chain and containing a hydrocarbon group in at least a portion of the side chain.

[0097] Q 1 and Q 2 In terms of the effect of surface localization, the organopolysiloxane group in 1 is a monovalent organopolysiloxane group represented by the following (Si-1), and Q 2 Examples of the divalent organopolysiloxane group include the divalent organopolysiloxane group represented by the following (Si-2).

[0098] [ka] (In formulas (Si-1) and (Si-2), R 11 each independently represents a monovalent hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, a hydrogen atom, a hydroxyl group, an alkoxy group having 1 to 20 carbon atoms, or a group represented by the following general formula (Si-3): 2 represents a monovalent hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, a hydrogen atom, a hydroxyl group, an alkoxy group having 1 to 20 carbon atoms, an amino group, a carboxy group, or a (meth)acryloyloxy group. Each a independently represents a number from 1 to 100.

[0099] [ka] (In formula (Si-3), R 12 each independently represents a monovalent hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, a hydrogen atom, a hydroxyl group, or an alkoxy group having 1 to 20 carbon atoms, and b represents a number from 0 to 100.

[0100] R 11 and R 12 The monovalent hydrocarbon group having 1 to 20 carbon atoms which may have a substituent in R 2 R may be the same as the hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. 11 and R 12 In the above, the monovalent hydrocarbon group having 1 to 20 carbon atoms which may have a substituent is preferably a hydrocarbon group having 1 to 10 carbon atoms which may have a substituent. Specific examples thereof include alkyl groups such as a methyl group, an ethyl group, a propyl group, and a butyl group; cycloalkyl groups such as a cyclohexyl group; aryl groups such as a phenyl group and a tolyl group; aralkyl groups such as a benzyl group and a phenethyl group; and hydroxypropyl groups, cyanoethyl groups, 1-chloropropyl groups, and 3,3,3-trifluoropropyl groups in which some or all of the hydrogen atoms bonded to the carbon atoms of these groups have been substituted with hydroxy groups, cyano groups, halogen atoms, or the like.

[0101] R 11 and R 12 The alkoxy group having 1 to 20 carbon atoms in is preferably an alkoxy group having 1 to 10 carbon atoms, and specific examples thereof include a methoxy group, an ethoxy group, a propoxy group, and a butoxy group.

[0102] R 11 and R 12 From the viewpoint of solubility in organic solvents, R is preferably an alkyl group having 1 to 10 carbon atoms, an aryl group, or a group represented by the general formula (Si-3) above, and more preferably an alkyl group having 1 to 5 carbon atoms. 12 is preferably an alkyl group or aryl group having 1 to 10 carbon atoms, and more preferably an alkyl group having 1 to 5 carbon atoms.

[0103] J2 J represents a monovalent hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, a hydrogen atom, a hydroxyl group, an alkoxy group having 1 to 20 carbon atoms, an amino group, a carboxy group, or a (meth)acryloyloxy group. 2 is preferably a monovalent hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, a hydrogen atom, or an alkoxy group having 1 to 20 carbon atoms, but may also be a hydroxyl group, an amino group, a carboxy group, or a (meth)acryloyloxy group. 2 When the compound has such a reactive group, it may be used, for example, to bond other components in the release layer 12 to the gas generating agent.

[0104] When preparing the compound of general formula (2), even if a gas-generating moiety is not introduced to both ends but is introduced to only one end, the compound may have the structure of general formula (1) and may have a reactive group such as a hydroxyl group, an amino group, a carboxyl group, or a (meth)acryloyloxy group at the end.

[0105] In the general formulae (Si-1) and (Si-2), a represents a number from 1 to 100. Since a may have a distribution, it may be an average value. In particular, from the viewpoint of the nitrogen content in one molecule, a preferably represents a number from 1 to 50, more preferably a number from 5 to 45, and further preferably a number from 10 to 40.

[0106] In addition, in the general formula (Si-3), b represents a number from 0 to 100. Since b may also have a distribution, it may be an average value. Among them, b preferably represents a number from 0 to 40, and more preferably represents a number from 0 to 30.

[0107] Q 1 is preferably a monovalent fluorinated aliphatic hydrocarbon group which has 2 to 8 carbon atoms directly bonded to fluorine atoms, which may contain an ether bond (-O-) in the carbon chain, and which may have a substituent; Q 2 is preferably a divalent fluorinated aliphatic hydrocarbon group having 2 to 8 carbon atoms directly bonded to fluorine atoms and which may contain an ether bond (-O-) in the carbon chain.

[0108] Meanwhile, in the general formulae (1) and (2), L each independently represents a direct bond or a divalent linking group. In the general formulae (1) and (2), L represents a site that links the gas-generating part and the specific fluorinated aliphatic hydrocarbon group or organopolysiloxane group, and is not particularly limited as long as it is a linking site that can bond the specific fluorinated aliphatic hydrocarbon group or organopolysiloxane group to the gas-generating part.

[0109] In addition, the direct bond means that L does not have an atom, that is, the carbon atom of A in the general formulas (1) and (2) and the carbon atom of Q 1 Or Q 2 This means that the carbon atom or silicon atom of the group is bonded to the group without any other atom being interposed therebetween.

[0110] L in the general formulae (1) and (2) each independently includes, for example, a direct bond, -SCH2CH2COO-, -SCH2CH(CH3)COO-, -SCH2CH(OH)CH2-, -OCH2CH(OH)CH2-, -SCH(CH3)O-, -OCH(CH3)O-, -COO-, -CONH-, -COS-, -SON2NH-, or a hydrocarbon group having 1 to 22 carbon atoms which may contain one or more selected from the group consisting of -O- and -S- and which may be substituted with a hydroxyl group, or a combination thereof. Note that the bond direction in L may be arbitrary. That is, when L is -SCH2CH2COO-, S is bonded to the carbon atom of A, and O is bonded to the carbon atom of Q. 1 Or Q 2 When S is bonded to a carbon atom or silicon atom of Q 1 Or Q 2 and O is bonded to a carbon atom or silicon atom of A.

[0111] Examples of the hydrocarbon group having 1 to 22 carbon atoms include alkylene groups such as a methylene group, an ethylene group, a propylene group (a trimethylene group, a methylethylene group), a butylene group (a tetramethylene group, a methylpropylene group), a pentamethylene group, a hexamethylene group, an octamethylene group, and a cyclohexylene group, an arylene group such as a phenylene group, and a combination of two or more of these groups (an alkylenearylene group).

[0112] Examples of the combination of L in the general formulae (1) and (2) include: (L1):-SCH2CH2COO-(C j H 2j )-, (L2):-SCH2CH2COO-(C j H 2j )-O-(C k H 2k )-, (L3):-SCH2CH2COO-(C j H 2j )-NHCO-(C k H 2k )-, (L4):-SCH2CH2CO-OCH2CH(OH)CH2O-(C j H 2j )-, (L5): -SCH2CH2CO-OCH2CH(OH)-(C j H 2j )-, (L6):-SCH2CH2COO-(C j H 2j )-NHCO-CH{CHO-(C k H 2k )-Rf}-CH2O-(C l H 2l )-, (L7): -SCH2CH2COO-CH{CH2O-(C j H 2j )-Rf}-CH2O-(C k H 2k )-, (L8):-SCH2CH2COO-(C j H 2j )-N(C k H2k+1 )SO2-, (L9):-SCH2CH2CON(C j H 2j+1 )-(C k H 2k )-, (L10):-SCH2CH2COO-(C j H 2j )-N(C k H 2k+1 )CO-, (L11): -OCH(CH3)O-(C j H 2j )- and the like (wherein j, k, and l each independently represent an integer of 1 to 8, and Rf is any one of the monovalent fluorinated aliphatic hydrocarbon groups represented by general formulas (Rf-1) to (Rf-3) above).

[0113] The above j, k, and l each independently preferably represent an integer of 2 to 6, and more preferably an integer of 2 to 4.

[0114] From the viewpoint of foaming properties in the ultraviolet region, the gas generating agent of the present invention is preferably one which is represented by at least one of the following (1-1) and (2-1), has a maximum molar absorption coefficient of 7000 or more at a wavelength of 240 nm or more and 450 nm or less, and generates gas upon irradiation with light.

[0115] [ka] (In the general formulas (1-1) and (2-1), R 1 , L, Q 1 , and Q 2 each independently represents the same as in general formula (1) and general formula (2).

[0116] Examples of the compound represented by the general formula (1-1) include, but are not limited to, the following compounds. For example, A is the above-mentioned (a-1-1) to (a-1-15), L is the above-mentioned (L1) to (L11), Q is the above-mentioned (a-1-2) to (a-1-3), and Q is the above-mentioned (a-1-4). 1Examples of the compound include any combination of the above (Rf-1) to (Rf-5) and (Si-3).

[0117] [Table 1]

[0118] Examples of the compound represented by the general formula (2-1) include, but are not limited to, the following compounds. For example, A is the above-mentioned (a-1-1) to (a-1-15), L is the above-mentioned (L1) to (L11), Q is the above-mentioned (L2) to (L3), and 2 Examples of the compound include any combination of the above (Rf-6) and (Si-2).

[0119] [Table 2]

[0120] The gas generating agent of the present disclosure can efficiently generate gas by light irradiation since the maximum molar absorption coefficient at wavelengths of 240 nm or more and 450 nm or less is 7000 or more. From the viewpoint of efficiently generating gas and improving ease of peeling, the gas generating agent of the present disclosure preferably has a maximum molar absorption coefficient at wavelengths of 240 nm or more and 450 nm or less of 8000 or more, more preferably 9000 or more.

[0121] The molar absorption coefficient in this specification refers to a value obtained by dissolving a gas generating agent in ethyl acetate to a concentration of 0.1 mM, measuring an absorption spectrum in a wavelength region of 230 nm or more and 800 nm or less using an ultraviolet-visible spectrophotometer (e.g., Shimadzu Corporation's ultraviolet-visible spectrophotometer UV2700), and calculating the absorbance in the obtained absorption spectrum according to the following formula. ε=A / c×d (In the formula, ε represents the molar extinction coefficient, A represents the absorbance, c represents the molar concentration, and d represents the cell thickness.)

[0122] If the gas generating agent does not dissolve in ethyl acetate at 0.1 mM, a solvent that does not cause problems in the reproducibility of the molar absorption coefficient of the gas generating agent is appropriately selected, dissolved in 0.1 mM, and the above-mentioned determination is performed. Examples of solvents that do not cause problems in the reproducibility of the molar absorption coefficient of the gas generating agent include organic solvents that do not have an absorption spectrum in the wavelength range of 230 nm to 800 nm and do not react with the gas generating agent, and specific examples include acetonitrile, dichloromethane, etc.

[0123] In this specification, the maximum molar absorption coefficient of 7000 or more at a wavelength of 240 nm or more and 450 nm or less means that the value of the molar absorption coefficient at any wavelength between 240 nm or more and 450 nm or less is 7000 or more, and it is not necessary that there is no peak between 240 nm or more and 450 nm or less.

[0124] The molecular weight or mass average molecular weight Mw of the gas generating agent of the present disclosure is not particularly limited, but is preferably 200 to 2000, and more preferably 300 to 1000, from the viewpoint of the nitrogen atom content in one molecule.

[0125] Here, the molecular weight of the gas generating agent can be determined by liquid chromatography mass spectrometry (LC-MS).

[0126] In addition, when the gas generating agent contains an organopolysiloxane group, it may be specified by the mass average molecular weight, which can be determined by gel permeation chromatography (GPC) in terms of standard polystyrene.

[0127] The method for producing the gas generating agent of the present disclosure is not particularly limited, and for example, the gas generating agent of the present disclosure can be obtained by reacting and bonding a gas generating part having a reactive group with a compound having a reactive group that reacts with the reactive group of the gas generating part to form a bond and a fluorinated aliphatic hydrocarbon group or an organopolysiloxane group.

[0128] Examples of combinations of reactive groups include, but are not limited to, a thiol group and a (meth)acryloyloxy group, a thiol group and an epoxy group, a thiol group and a vinyl ether group, a hydroxyl group and a vinyl ether group, a hydroxyl group and an epoxy group, a hydroxyl group and an isocyanate group, an amino group and a sulfonyl chloride group, a carboxyl group and an epoxy group, etc. In each combination, which one is the reactive group on the gas generating part side, and which one is the reactive group on the compound having a fluorinated aliphatic hydrocarbon group or an organopolysiloxane group side.

[0129] A gas generating unit having a reactive group can be synthesized, for example, by referring to Russian Journal of General Chemistry (2017), 87(4), p.731-738. For example, a tetrazole compound substituted with a thiol group and R (an aromatic group having 3 to 20 carbon atoms) can be synthesized by reacting an isothiocyanate derivative (RN=C=S, where R is an aromatic group having 3 to 20 carbon atoms) with sodium azide. Also, a naphthoquinone diazide compound having a sulfonic acid chloride group can be synthesized by referring to JP-A-59-196860. Also, an azo compound having a carboxyl group can be synthesized by reacting sodium cyanide with 4-oxopentanoic acid and hydrazine monohydrate by referring to Shandong Huagong, Volume: 37, Issue: 3, Pages: 7-9, Journal, 2008. Alternatively, a commercially available product may be appropriately selected and used as the gas generating part having a reactive group.

[0130] In addition, a compound having a reactive group and a fluorinated aliphatic hydrocarbon group or an organopolysiloxane group can be synthesized by reacting a naphthoquinone diazide compound having a sulfonic acid chloride group with an organopolysiloxane compound having an amino group, for example, with reference to Patent No. 6137289, Chemistry Select, Volume: 3, Issue: 15, Pages: 4129-4132, Journal, 2018. In addition, a compound having a fluorinated aliphatic hydrocarbon group can be synthesized by reacting a vinyl ether group having a fluorinated aliphatic hydrocarbon group with an azo compound having a carboxyl group, for example, with reference to Macromolecules, Volume: 37, Issue: 18, Pages: 6673-6675, Journal, 2004. Alternatively, as the compound having a reactive group and a fluorinated aliphatic hydrocarbon group or an organopolysiloxane group, a commercially available product may be appropriately selected and used.

[0131] The gas generating agent of the present disclosure has the specific fluorinated aliphatic hydrocarbon group or the specific organopolysiloxane group in the gas generating part having the specific structure, and is therefore likely to be localized on the surface. Therefore, the gas generating agent of the present disclosure is preferably used for the material of the peeling layer 12 for the purpose of high adhesion and easy peeling, and is preferably used for improving easy peeling.

[0132] The release layer 12 may contain the gas generating agent, the adhesive component, and the gas generating agent of the present disclosure. In this case, since the release layer 12 contains the gas generating agent of the present disclosure, the amount of gas generated on the surface of the release layer 12 is efficiently increased by the action of the gas generating agent that is likely to be localized on the surface as described above. Therefore, it is possible to form a release layer 12 that has good adhesive strength when used when adhesive strength is required, and has excellent easy peelability from the adherend when adhesive strength for peeling the release layer 12 from the adherend is no longer required.

[0133] The adhesive component is not particularly limited, and may be a non-photocurable adhesive component or a photocurable adhesive component.

[0134] When the adhesive component is a non-photocurable adhesive component, gas is generated from the gas generating agent of the present disclosure upon irradiation with light, and peel stress is generated by the generated gas, and the adhesive area with the adherend is reduced, causing each layer to peel off.

[0135] When the adhesive component is a photocurable adhesive component, the adhesive component is photocured by irradiating light. This reduces the adhesive strength of the adhesive component itself. In addition, the gas generated from the gas generating agent of the present disclosure reduces the adhesion area with the adherend. Therefore, the synergistic effect of these factors makes peeling easier. Therefore, it is preferable that the adhesive component is a photocurable adhesive component.

[0136] The photocurable adhesive component is not particularly limited, but examples thereof include those that contain an adhesive, a photocurable component, and a photoinitiator.

[0137] The photocurable adhesive component may be (i) a composition containing an adhesive, a photocurable multifunctional compound, and a photoinitiator, or (ii) a composition containing an adhesive having two or more photocurable functional groups in one molecule, and a photoinitiator. Of these, the photocurable adhesive component is preferably (i) a composition containing an adhesive, a photocurable multifunctional compound, and a photoinitiator, in that the adhesive strength can be easily adjusted. In the case of (i), the adhesive may have a photocurable functional group.

[0138] (Adhesive) The adhesive is not particularly limited, and examples thereof include rubber-based adhesives, acrylic-based adhesives, vinyl alkyl ether-based adhesives, silicone-based adhesives, polyester-based adhesives, polyamide-based adhesives, urethane-based adhesives, and styrene-diene block copolymer-based adhesives.

[0139] As the adhesive, from the viewpoints of compatibility with the photocurable component and adjustment of adhesive strength, it is preferable to use a (meth)acrylic acid ester polymer, which is called an acrylic adhesive.

[0140] As the (meth)acrylic acid ester-based polymer, it is preferable to use a (meth)acrylic acid ester-based copolymer obtained by copolymerizing a structural unit derived from a (meth)acrylic acid alkyl ester monomer having a linear or branched alkyl group having 1 to 20 carbon atoms, which is used as an acrylic pressure-sensitive adhesive, with other monomers as necessary.

[0141] Among the (meth)acrylic acid ester-based polymers, a (meth)acrylic acid ester-based copolymer having a constituent unit derived from a (meth)acrylic acid alkyl ester monomer having a carbon number of 1 to 20 inclusive in a linear or branched alkyl group and a constituent unit derived from a crosslinkable group-containing monomer is preferred. The (meth)acrylic acid ester-based copolymer can be crosslinked with a thermal crosslinking agent or the like described below by utilizing the crosslinkable group introduced into the molecule of the (meth)acrylic acid ester polymer, thereby improving the cohesive force of the release layer 12 and enabling the production of a release layer 12 having a good balance between easy removability and durability under a specified environment.

[0142] Examples of (meth)acrylic acid alkyl ester monomers in which the carbon number of the linear or branched alkyl group is 1 or more and 20 or less include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, n-decyl (meth)acrylate, isodecyl (meth)acrylate, n-dodecyl (meth)acrylate, n-tridecyl (meth)acrylate, n-tetradecyl (meth)acrylate, n-hexadecyl (meth)acrylate, and n-octadecyl (meth)acrylate, either alone or in combination of two or more thereof. Among these, from the viewpoint of exhibiting wettability and adhesiveness to an adherend, a (meth)acrylic acid alkyl ester having a linear or branched alkyl group having 4 to 14 carbon atoms is preferred, and a (meth)acrylic acid alkyl ester having a linear or branched alkyl group having 7 to 13 carbon atoms is more preferred.

[0143] Examples of the crosslinkable group of the crosslinkable group-containing monomer used in the (meth)acrylic acid ester polymer include a hydroxyl group, an epoxy group, an isocyanate group, a carboxyl group, and an amino group.

[0144] From the viewpoint of stability during polymerization and storage of the polymer, it is preferable that the polymer contains a structural unit derived from a monomer containing one or more groups selected from the group consisting of a hydroxyl group, an epoxy group, a carboxyl group, and an amino group, and it is preferable that the polymer contains a structural unit derived from a hydroxyl group-containing monomer, from the viewpoints of high stability and excellent reactivity of the thermal crosslinking agent.

[0145] Examples of monomers that derive structural units derived from hydroxyl group-containing monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and glycerin mono(meth)acrylate.

[0146] Examples of monomers that derive structural units derived from epoxy group-containing monomers include glycidyl (meth)acrylate and 3,4-epoxycyclohexylmethyl (meth)acrylate.

[0147] Examples of monomers that derive structural units derived from isocyanate group-containing monomers include 2-(meth)acryloyloxyethyl isocyanate and alkylene oxide adducts thereof.

[0148] Examples of monomers that derive structural units derived from amino group-containing monomers include ethylaminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, and the like.

[0149] Examples of monomers that derive structural units derived from carboxy group-containing monomers include (meth)acrylic acid, vinylbenzoic acid, maleic acid, and ω-carboxy-polycaprolactone mono(meth)acrylate.

[0150] The (meth)acrylic acid ester polymer may further have a photocurable functional group in the side chain.

[0151] The photocurable functional group preferably has an ethylenically unsaturated bond, and is preferably a (meth)acryloyl group, a vinyl group, an allyl group, or the like.

[0152] As a method for introducing a photocurable functional group into the side chain of the (meth)acrylic acid ester polymer, a conventionally known production method may be appropriately selected and used.

[0153] For example, a photocurable functional group can be added by reacting a (meth)acrylic acid ester polymer having a carboxy group with glycidyl (meth)acrylate, by reacting a (meth)acrylic acid ester polymer having an isocyanate group with hydroxyethyl (meth)acrylate, or by reacting a (meth)acrylic acid ester polymer having a hydroxyl group with 2-isocyanatoethyl (meth)acrylate.

[0154] The (meth)acrylic acid ester polymer may contain structural units derived from other monomers as long as they function as an acrylic pressure-sensitive adhesive.

[0155] As the other monomers, for example, rigid monomers such as cyclohexyl methacrylate, benzyl methacrylate, and adamantyl methacrylate can be used.

[0156] Since the (meth)acrylic acid ester monomer is the main component constituting the (meth)acrylic acid ester-based polymer, it is usually preferable that the content thereof is 50% by mass or more based on the total monomer components (100% by mass).

[0157] The content of the (meth)acrylic acid alkyl ester monomer is, for example, 50% by mass or more, optionally 60% by mass or more, optionally 80% by mass or more, or optionally 90% by mass or more, based on the total monomer components, while the content of the (meth)acrylic acid alkyl ester monomer is, for example, 99.5% by mass or less, optionally 99% by mass or less, or optionally 98% by mass or less, based on the total monomer components.

[0158] The content of the crosslinkable group-containing monomer may be appropriately selected from the viewpoint of the balance between adhesive strength and peel strength. In this case, the content of the crosslinkable group-containing monomer may be, for example, 0.5% by mass or more, 1% by mass or more, or 2% by mass or more, based on the total monomer components. On the other hand, the content of the crosslinkable group-containing monomer may be, for example, 15% by mass or less, 13% by mass or less, or 10% by mass or less, based on the total monomer components.

[0159] The content of the other monomer in the (meth)acrylic acid ester polymer may be appropriately selected in terms of the balance between adhesive strength and peel strength and the desired performance, and may be, for example, 0 mass% or more and 49.5 mass% or less, or may be 39 mass% or less, or may be 18 mass% or less.

[0160] The mass average molecular weight of the (meth)acrylic acid ester polymer is preferably 100,000 to 5 million, more preferably 200,000 to 4 million, even more preferably 300,000 to 3 million, and even more preferably 400,000 to 1 million, in terms of improving adhesive strength and peel strength. By having a mass average molecular weight of 100,000 or more, it is possible to suppress a decrease in cohesive strength. Therefore, it is possible to effectively obtain the effect of adhesiveness while suppressing the occurrence of adhesive residue on the adherend surface after peeling. In addition, by having a mass average molecular weight of 5 million or less, it is possible to improve the wettability of the adherend surface after peeling off the release layer 12.

[0161] The mass average molecular weight of the (meth)acrylic acid ester polymer can be determined by gel permeation chromatography (GPC) in terms of standard polystyrene.

[0162] As the (meth)acrylic acid ester polymer, a commercially available acrylic adhesive may be used, and for example, SK Dyne 2971 (manufactured by Soken Chemical Engineering Co., Ltd.), SK Dyne 2975 (manufactured by Soken Chemical Engineering Co., Ltd.), SK Dyne 1811L (manufactured by Soken Chemical Engineering Co., Ltd.), SK Dyne 2950 (manufactured by Soken Chemical Engineering Co., Ltd.), SK Dyne 2094 (manufactured by Soken Chemical Engineering Co., Ltd.), Olivine EG-654 (manufactured by Toyochem Co., Ltd.) and the like can be suitably used.

[0163] The pressure-sensitive adhesives may be used alone or in combination of two or more.

[0164] The content of the adhesive may be, for example, 20% by mass or more, or 30% by mass or more, based on the solid content of the release layer 12, from the viewpoint of adhesive strength effect. Also, the content of the adhesive may be, for example, 80% by mass or less, or 70% by mass or less, based on the solid content of the release layer 12, from the viewpoint of re-peeling of the release layer 12.

[0165] In this specification, the solid content means all components other than the solvent.

[0166] (Photocurable polyfunctional compound) The photocurable component preferably contains a photocurable polyfunctional compound, which is a monomer, oligomer, or polymer containing two or more photocurable groups in one molecule.

[0167] By including a photocurable polyfunctional compound, three-dimensional crosslinking can be achieved, and further, when the (meth)acrylic acid ester-based polymer has photocurability, the compound reacts with the (meth)acrylic acid ester-based polymer to increase the molecular weight of the (meth)acrylic acid ester-based polymer or to three-dimensionally crosslink the (meth)acrylic acid ester-based polymer.

[0168] By including a photocurable component, the adhesion to the substrate, cohesiveness, etc., of the release layer 12 formed can be easily controlled within a desired range.

[0169] Examples of the photocurable polyfunctional compound include 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, di(meth)acrylate of neopentyl glycol adipate, hydroxypivalic acid neopentyl glycol di(meth)acrylate, dicyclopentanyl di(meth)acrylate, caprolactone-modified dicyclopentenyl di(meth)acrylate, and the like. Acrylates, ethylene oxide modified phosphoric acid di(meth)acrylate, di(meth)acryloxyethyl isocyanurate, allylated cyclohexyl di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, dimethylol dicyclopentane di(meth)acrylate, ethylene oxide modified hexahydrophthalic acid di(meth)acrylate, neopentyl glycol modified trimethylolpropane di(meth)acrylate, adamantane di(meth)acrylate, 9,Bifunctional polyfunctional (meth)acrylate monomers such as 9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene, trifunctional polyfunctional (meth)acrylate monomers such as ethylene oxide-modified isocyanuric acid triacrylate, trimethylolpropane tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, propionic acid-modified dipentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propylene oxide-modified trimethylolpropane tri(meth)acrylate, tris(meth)acryloxyethyl isocyanurate, diglycerol tetra(meth)acrylate, For example, tetrafunctional (meth)acrylate such as pentafunctional dipentaerythritol penta(meth)acrylate, propionic acid modified dipentaerythritol hexa(meth)acrylate, hexafunctional (meth)acrylate such as dipentaerythritol hexa(meth)acrylate, caprolactone modified dipentaerythritol hexa(meth)acrylate, and oligomers having several (meth)acryloyl groups in the molecule and having a molecular weight of several hundred to several thousand, such as urethane (meth)acrylate, polyester (meth)acrylate, and epoxy (meth)acrylate, can be preferably used.

[0170] As the photocurable polyfunctional compound, from the viewpoint of the balance between adhesive strength and peel strength, it is preferable to use oligomers having a molecular weight of several hundred to several thousand and containing several (meth)acryloyl groups in the molecule, such as urethane (meth)acrylate, polyester (meth)acrylate, and epoxy (meth)acrylate.

[0171] The photocurable polyfunctional compounds can be used alone or in combination of two or more.

[0172] When a photocurable polyfunctional compound is used, the content of the photocurable polyfunctional compound relative to 100 parts by mass of the adhesive such as the (meth)acrylic acid ester-based polymer may be, for example, 10 parts by mass or more, 20 parts by mass or more, or 50 parts by mass or more, or alternatively, 300 parts by mass or less, 200 parts by mass or less, or 150 parts by mass or less.

[0173] By making the content of the photocurable multifunctional compound larger than the lower limit, the effect of adding the photocurable multifunctional compound can be effectively exhibited. Also, by making the content of the photocurable multifunctional compound smaller than the upper limit, the properties of the release layer 12, such as storage stability, adhesion to substrate, adhesiveness, and release property, can be prevented from being deteriorated.

[0174] From the viewpoint of the balance of the peeling force after light irradiation, the total content of the pressure-sensitive adhesive and the photocurable multifunctional compound may be, for example, 10% by mass or more, or may be 20% by mass or more, based on the solid content of the release layer 12. Moreover, from the viewpoint of the adhesive force and the suppression of contamination of the adherend, the total content of the pressure-sensitive adhesive and the photocurable multifunctional compound may be, for example, 70% by mass or less, or may be 60% by mass or less, based on the solid content of the release layer 12.

[0175] (Photoinitiator) Any compound capable of generating radicals when irradiated with a predetermined amount of light such as ultraviolet light can be used as the photoinitiator. Examples of such photoinitiators include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one, 4-(2-hydroxyethoxy)phenyl-2-(hydroxyphenyl)-1-propan-1-one, 1-hydroxycyclohexyl phenyl ketone ... dimethylthioxanthone, 2-methyl-2-propyl ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tertiary-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyl dimethyl ketal, acetophenone dimethyl ketal, p-dimethylaminobenzoic acid ester, oligo[2-hydroxy-2-methyl-1[4-(1-methylvinyl)phenyl]propanone], 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, and the like.

[0176] In addition, the photoinitiator is preferably at least one selected from the group consisting of acylphosphine oxide initiators, α-aminoalkylphenone initiators, α-hydroxyketone initiators, and oxime ester initiators, since this hardens the coating film to its interior and improves its durability.

[0177] The photoinitiators can be used alone or in combination of two or more.

[0178] The content of the photoinitiator may be, for example, 0.5% by mass or more, or 1.0% by mass or more, based on the solid content of the release layer 12, from the viewpoint of sufficiently curing the release layer 12. Moreover, the content of the photoinitiator may be, for example, 10.0% by mass or less, or 5.0% by mass or less, based on the solid content of the release layer 12, from the viewpoint of the balance between adhesive strength and peel strength.

[0179] (Thermal crosslinking agent) The release layer 12 of the present disclosure preferably further contains a thermal crosslinking agent. The thermal crosslinking agent is a compound that causes a crosslinking reaction to proceed by the action of heat.

[0180] By incorporating a thermal crosslinking agent into the release layer 12 of the present disclosure, it is possible to react with the crosslinkable groups contained in the adhesive, thereby eliminating the fluidity of the release layer 12 itself after film formation, and adjusting the adhesive strength or peel strength before light irradiation.

[0181] Examples of the thermal crosslinking agent include an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, a melamine-based crosslinking agent, an aziridine-based crosslinking agent, and a metal chelate-based crosslinking agent. Among these, an isocyanate-based crosslinking agent and an epoxy-based crosslinking agent are preferred because they tend to favorably exhibit the effects of the present disclosure.

[0182] Examples of the isocyanate crosslinking agent include lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate; aromatic isocyanates such as 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate and xylylene diisocyanate; and isocyanate adducts such as trimethylolpropane / tolylene diisocyanate trimer adduct (product name "Coronate L" manufactured by Nippon Polyurethane Industry Co., Ltd.), trimethylolpropane / hexamethylene diisocyanate trimer adduct (product name "Coronate HL" manufactured by Nippon Polyurethane Industry Co., Ltd.), and isocyanurate of hexamethylene diisocyanate (product name "Coronate HX" manufactured by Nippon Polyurethane Industry Co., Ltd.).

[0183] Examples of epoxy crosslinking agents include bisphenol A, epichlorohydrin-type epoxy resins, ethylene glycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, 1,6-hexanediol glycidyl ether, trimethylolpropane triglycidyl ether, diglycidylaniline, diamine glycidylamine, N,N,N',N'-tetraglycidyl-m-xylylenediamine (product name "TETRAD-X", manufactured by Mitsubishi Gas Chemical Co., Ltd.), and 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane (product name "TETRAD-C", manufactured by Mitsubishi Gas Chemical Co., Ltd.).

[0184] The thermal crosslinking agents can be used alone or in combination of two or more.

[0185] The content of the thermal crosslinking agent may be appropriately adjusted depending on the balance between the adhesive strength and the peel strength, but from the viewpoint of obtaining the above-mentioned effect, the content of the thermal crosslinking agent may be, for example, 1.0 mass% or more, or 2.0 mass% or more, based on the solid content of the adhesive composition. Also, from the viewpoint of the adhesiveness before energy irradiation, the content of the thermal crosslinking agent may be, for example, 10.0 mass% or less, or 8.0 mass% or less, based on the solid content of the adhesive composition.

[0186] The release layer 12 of the present disclosure contains the gas generating agent of the present disclosure.

[0187] Since the gas generating agent of the present disclosure tends to localize on the surface of the adhesive material, the amount of gas generated on the surface of the adhesive material can be efficiently increased without increasing the content of the gas generating agent in the release layer 12, which makes it easier to suppress a decrease in the adhesive strength and clouding of the adhesive material.

[0188] The content of the gas generating agent of the present disclosure may be, for example, 2% by mass or more, or 3% by mass or more, based on the solid content of the adhesive composition, from the viewpoint of effectively reducing the peeling force during peeling. Also, the content of the gas generating agent of the present disclosure may be, for example, 40% by mass or less, or 30% by mass or less, based on the solid content of the adhesive composition, from the viewpoint of suppressing the decrease in the adhesive force of the adhesive material and the clouding.

[0189] (solvent) The release layer 12 of the present disclosure may further contain a solvent. By containing a solvent, it is possible to improve the coatability with respect to other layers and the mixability of the blended components.

[0190] The solvent may be appropriately selected from those that do not react with the components in the composition and can dissolve or disperse them. Examples of the solvent include esters, aromatic hydrocarbons, ketones, and ethers.

[0191] More specifically, because they have good solubility in (meth)acrylic acid ester-based polymers and are easy to handle, examples of such solvents include methyl acetate, ethyl acetate, n-butyl acetate, i-butyl acetate, benzene, toluene, xylene, acetone, cyclohexane, cyclohexanone, methyl ethyl ketone, and tetrahydrofuran, either alone or in combination.

[0192] In addition, the content of the solvent may be appropriately adjusted in view of the coatability to other layers and the mixability of the blended components, but may be, for example, 5% by mass or more and 40% by mass or less relative to the total amount (100% by mass) of the adhesive composition including the solvent.

[0193] (Optional addition ingredient)

[0194] The release layer 12 of the present disclosure may further contain various additives as necessary, as long as the object of the present disclosure is not impaired.

[0195] Examples of the various additives include crosslinking accelerators, antioxidants, stabilizers, viscosity modifiers, tackifier resins, and organic or inorganic fillers.

[0196] Examples of the crosslinking accelerator include triethylamine-based, cobalt naphthenate-based, tin-based, zinc-based, titanium-based, zirconium-based, etc. When the crosslinking agent is an isocyanate-based crosslinking agent, it is preferable to use zinc-based, titanium-based, and zirconium-based accelerators such as alkoxides, acylates, and complexes, and tin-based accelerators such as stannous chloride, tetra-n-butyltin, stannic chloride, trimethyltin hydroxide, dimethyltin dichloride, and di-n-butyltin dilaurate.

[0197] The antioxidants include phenol-based antioxidants.

[0198] The method for producing the material constituting the release layer 12 is not particularly limited.

[0199] The material constituting the release layer 12 can be obtained by adding the above-mentioned components and various additives added as necessary in any order and dissolving or dispersing them. The above-mentioned components can be mixed using a mixer such as a dissolver, a planetary mixer, or a butterfly mixer, or a kneader.

[0200] The release layer 12 may have an initial adhesive strength before light irradiation, that is, a peel strength to the first sealant layer 11 at a peel speed of 300 mm / min and a peel angle of 180 degrees of 5 N / 25 mm or more and 25 N / 25 mm or less.

[0201] Furthermore, the peeling strength of the peeling layer 12 after light irradiation with respect to the first sealant layer 11 at a peeling speed of 300 mm / min and a peeling angle of 180 degrees may be 0 N / 25 mm or more and 1.0 N / 25 mm or less. The light irradiation amount may be appropriately selected. For example, the light irradiation amount is 3000 mJ / cm 2 The adhesive strength after ultraviolet (UV) irradiation can be used as an index of adhesive strength after light irradiation.

[0202] Generally, the faster the peeling speed, the greater the peeling force.

[0203] When the peeling layer 12 is heated to reduce the adhesive strength of the peeling layer 12, the peeling layer 12 may be heated to 70° C. or more and 90° C. or less. The heating time may be 5 minutes or more and 30 minutes or less. When the peeling layer 12 is exposed to light to reduce the adhesive strength of the peeling layer 12, ultraviolet light may be used as the exposure light as described above.

[0204] Methods for forming the release layer 12 include, for example, roll coating, gravure coating, gravure reverse coating, microgravure coating, slot die coating, die coating, knife coating, inkjet coating, dispenser coating, kiss coating, spray coating, screen printing, offset printing, and flexographic printing.

[0205] In the present embodiment, the thickness of the release layer 12 is preferably not less than 3 μm and not more than 8 μm.

[0206] <<Second sealant layer>> The second sealant layer 13 is a layer for bonding the tube container packaging materials 10 together. For example, the second sealant layer 13 is a layer that becomes the innermost layer when a tube container 40 (described later) is produced from the tube container packaging material 10. The second sealant layer 13 is preferably made of a virgin resin. In this way, the second sealant layer 13 that becomes the innermost layer of the tube container 40 is made of a virgin resin, thereby improving the hygiene of the tube container 40.

[0207] The material constituting the second sealant layer 13 is a material that melts and fuses by heat. In this case, the second sealant layer 13 contains a material of the same resin type as that constituting at least 90% or more of the first sealant layer 11. That is, the material constituting the second sealant layer 13 is a material of the same resin type as that constituting the first sealant layer 11. For example, polyolefin may be used for the second sealant layer 13. More specifically, for example, the second sealant layer 13 may be a resin made of one or more of acid-modified polyolefin resins obtained by modifying polyolefin resins such as low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), polypropylene, polyethylene, or polypropylene with acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, or other unsaturated carboxylic acids, polyvinyl acetate resins, polyester resins, polystyrene resins, polyacrylonitrile, saturated polyester, or polyvinyl alcohol.

[0208] The second sealant layer 13 may contain a biomass-derived resin. For example, when the second sealant layer 13 contains polyethylene, the polyethylene may contain a biomass-derived component. When the second sealant layer 13 contains a biomass-derived resin, the amount of fossil fuel used can be reduced, and the environmental impact of the tube container packaging material 10 can be reduced.

[0209] The material for the second sealant layer 13 may be a material to which, for example, an antiblocking agent, a lubricant (fatty acid amide, etc.), a flame retardant, an inorganic or organic filler, etc. are optionally added.

[0210] In the present embodiment, the thickness of the second sealant layer 13 is preferably not less than 50 μm and not more than 250 μm.

[0211] <<Base material layer>> The base layer 14 is a layer for supporting, for example, the first sealant layer 11 and the second sealant layer 13, and for increasing the strength of the entire packaging material 10 for tube containers. The base layer 14 may be made of a film made from the above-mentioned resin pellets 1, similar to the first sealant layer 11. In addition, as the base layer 14, in addition to a film made from the resin pellets 1, a resin film constituting a normal packaging material may be appropriately used. As a material constituting the base layer 14, for example, a polyester-based resin, a polyamide-based resin, a polyaramid-based resin, a polyolefin-based resin, a polycarbonate-based resin, a polyacetal-based resin, a fluorine-based resin, a film or sheet of other tough resin, and others may be used. As an example, the base layer 14 may contain polyethylene terephthalate. When the base layer 14 contains a polyester-based resin, the polyester-based resin may contain a biomass polyester. Biomass polyester refers to a polyester obtained from a raw material containing a monomer derived from biomass.

[0212] The resin film or sheet may be an unstretched film, or a uniaxially or biaxially stretched film, etc. Among these, in the present embodiment, a biaxially stretched polyester resin film is preferred because of its excellent printability.

[0213] In the present embodiment, the thickness of the base layer 14 is preferably not less than 10 μm and not more than 25 μm.

[0214] <<Barrier layer>> The barrier layer 15 is a layer for suppressing the permeation of oxygen gas, water vapor, etc. By providing the tube container packaging material 10 with the barrier layer 15, the permeation of oxygen gas, etc. can be suppressed, and weight loss and deterioration of the contents can be effectively suppressed.

[0215] The barrier layer 15 may be, for example, a vapor-deposited film of an inorganic substance or an inorganic oxide, or a layer made of a gas barrier resin such as an ethylene-vinyl alcohol copolymer, polyvinylidene chloride, polyvinyl alcohol, or MXD6, etc. The barrier layer 15 may also be formed by a combination of the above-mentioned vapor-deposited films or layers made of gas barrier resins.

[0216] In order to ensure the visibility of the contents, the barrier layer 15 is preferably transparent. In this case, a vapor deposition film of an inorganic oxide may be particularly preferably used as the barrier layer 15. The inorganic oxide forming the vapor deposition film may be an inorganic oxide that is transparent and has gas barrier properties against oxygen gas, water vapor, and the like. Examples of such inorganic oxides include oxides such as aluminum oxide, silicon oxide, magnesium oxide, calcium oxide, zirconium oxide, titanium oxide, boron oxide, hafnium oxide, and barium oxide. Among these, aluminum oxide and silicon oxide may be particularly preferably used in terms of gas barrier properties and production efficiency.

[0217] <<adhesive layer>> The adhesive layers such as the first adhesive layer 16a and the second adhesive layer 16b are layers for bonding the first sealant layer 11, the release layer 12, the second sealant layer 13, etc. to each other. The material constituting the adhesive layer can be appropriately selected depending on the resin constituting the layer to be bonded.

[0218] The adhesive layer may be, for example, an anchor coating agent such as an isocyanate (urethane), polyethyleneimine, polybutadiene, or organic titanium. The adhesive layer may be, for example, a polyurethane, polyacrylic, polyester, epoxy, polyvinyl acetate, cellulose, or other laminating adhesive.

[0219] As materials constituting the adhesive layer, for example, polyethylene, polypropylene, ethylene-vinyl alcohol, ethylene-methacrylic acid copolymer (EMAA), ethylene-acrylic acid copolymer, ionomer, maleic anhydride modified polyolefin resin, etc. can be suitably used.

[0220] In the present embodiment, the thickness of each adhesive layer is preferably not less than 3 μm and not more than 60 μm.

[0221] <<Print layer>> The printed layer 17 is a layer for enhancing the design of the tube container packaging material 10 and the like. The printed layer 17 is a layer on which a picture such as a predetermined character, figure, pattern, or color coding is formed by ink. A known ink may be used. For example, the ink may contain at least one of an organic pigment and an inorganic pigment, and a binder resin, and may further contain various additives as necessary. The printed layer 17 can be formed, for example, on the base material layer 14 by a known printing method such as gravure printing, offset printing, letterpress printing, or screen printing.

[0222] <<Middle layer>> The intermediate layer 18 is a layer for increasing the strength of the entire tube container packaging material 10. The intermediate layer 18 is preferably made of a material having impact resistance and pinhole resistance. For example, a polyamide resin film such as a biaxially oriented nylon film may be used as the intermediate layer 18. The thickness of the intermediate layer 18 may be appropriately determined depending on the use and function of the tube container packaging material 10. The thickness of the intermediate layer 18 may be, for example, about 15 μm or more and 25 μm or less.

[0223] In such a tube container packaging material 10, the first sealant layer 11, the peeling layer 12, the second sealant layer 13, etc. may be laminated to each other by, for example, a wet lamination method, a dry lamination method, a solventless dry lamination method, an extrusion lamination method, a co-extrusion lamination method, an inflation method, or any other method. In addition, when carrying out the above-mentioned lamination, the films constituting each layer may be subjected to a pretreatment such as a corona treatment or an ozone treatment.

[0224] Furthermore, the recycled resin content in the tube container packaging material 10 may be 20% by weight or more and 80% by weight or less. When the recycled resin content is 20% by weight or more, the environmental impact of the tube container packaging material 10 can be effectively reduced. When the recycled resin content is 80% by weight or less, the hygiene of the tube container 40 produced from the tube container packaging material 10 can be improved.

[0225] Next, a tube container 40 including the tube container packaging material 10 according to this embodiment will be described.

[0226] As shown in Fig. 4, the tube container 40 includes a body tube 41, which is a laminated molded tube, and a head member 43 joined to one end 42 of the body tube 41. The body tube 41 has a generally cylindrical shape. The body tube 41 includes a tube container packaging material 10. In this case, the body tube 41 may be configured such that an outer surface 101 of the tube container packaging material 10 faces away from the contents, and an inner surface 102 faces the contents.

[0227] The body tube 41 has a body seal portion 44 formed by joining together the tube container packaging material 10. This body seal portion 44 is formed along the longitudinal direction of the body tube 41. Such a body tube 41 may be obtained, for example, by rolling the tube container packaging material 10 into a cylindrical shape, overlapping opposing ends, and joining them together, for example, by heat sealing.

[0228] The body tube 41 also has a bottom seal portion 45 where the tube container packaging materials 10 are joined together. The bottom seal portion 45 is a portion where the tube container packaging materials 10 are joined together near an opening (not shown) formed at the other end 46 of the body tube 41 after an appropriate amount of content C is filled into the tube container packaging materials 10.

[0229] The head member 43 has a shoulder portion 47 and a mouth portion 48. A cap 49 is attached to the mouth portion 48. The head member 43 is molded by, for example, compression molding. The head member 43 is made of, for example, a resin material such as high density polyethylene (HDPE).

[0230] Next, the operation of this embodiment having the above-mentioned configuration, that is, the method for recycling the resin body and the method for producing the resin pellets 1 will be described.

[0231] First, the resin body is collected (collection step, reference symbol S1 in FIG. 5). At this time, the resin body may be a resin product (tube container 40) that has been used on the market, or may be a material (packaging material 10 for tube containers or tube container 40) generated in a resin product manufacturing process before it is released to the market. The resin body may be another packaging material 10 for tube containers or tube container 40 made from resin pellets 1.

[0232] Next, the collected resin body (the tube container packaging material 10 or the tube container 40) is crushed (crushing step, reference symbol S2 in FIG. 5). The resin body may be crushed using, for example, a crusher (shredder), a crushing mill (hammer mill), or a grinder (grinder). The resin body may also be crushed into pieces of, for example, about 10 mm x 10 mm in size.

[0233] Next, the crushed resin body is stirred in water to remove foreign matter from the crushed resin body (foreign matter removal step, reference symbol S3 in FIG. 5). This results in resin flakes from which dirt and foreign matter adhering to the resin body have been removed. In addition, in the foreign matter removal step, foreign matter removal and washing of the resin body may be performed using a washing liquid containing an aqueous sodium hydroxide solution or other surfactants. Note that, if necessary, a decontamination step for removing contaminants may be performed. In the foreign matter removal step, for example, the temperature of the water in the stirrer may be 20° C. or higher and 70° C. or lower. In addition, the stirring speed may be 150 rpm or higher and 250 rpm or lower. Furthermore, the stirring time may be 30 minutes or higher and 60 minutes or lower.

[0234] Next, the crushed resin body is heated or exposed to light to reduce the adhesive force of the release layer 12, thereby separating the first sealant layer 11 from the second sealant layer 13 (separation step, reference symbol S4 in FIG. 5). As described above, the release layer 12 is made of a material whose adhesive force decreases when heated or exposed to light. Therefore, the adhesive force of the release layer 12 decreases when the resin body is heated or exposed to light. As a result, the first sealant layer 11 and the second sealant layer 13 are separated from each other. In the separation step, for example, the release layer 12 may be heated to 70° C. or higher and 90° C. or lower. The heating time may be 5 minutes or higher and 30 minutes or lower. The release layer 12 may be exposed to light. In this case, ultraviolet light may be irradiated onto the release layer 12 as the exposure light.

[0235] Next, the first sealant layer 11 separated from the second sealant layer 13 is dried and sorted (drying and sorting step, reference symbol S5 in FIG. 5). At this time, the first sealant layer 11 may be sorted by various sorting methods such as a specific gravity sorting method, a wind sorting method, or an electrostatic sorting method. In the drying and sorting step, the drying temperature may be 20° C. or more and 50° C. or less. The drying time may be 30 minutes or more and 180 minutes or less.

[0236] Next, the selected first sealant layer 11 is pulverized (pulverization step, reference symbol S6 in FIG. 5). The first sealant layer 11 may be pulverized using, for example, a pulverizer (shredder), a pulverizing mill (hammer mill), or a grinder. The first sealant layer 11 may be pulverized to a size of, for example, about 5 mm x 5 mm.

[0237] Next, the pulverized first sealant layer 11 is melted (melting step, reference symbol S7 in FIG. 5). The first sealant layer 11 is melted, for example, in a pellet producing device (not shown). In the melting step, the melting temperature may be 170° C. or more and 200° C. or less.

[0238] Next, the resin pellets 1 are formed from the molten first sealant layer 11 (molding step, reference symbol S8 in FIG. 5). At this time, the molten first sealant layer 11 is first extruded in a string-like shape from a filter in a pellet producing device (not shown). Then, the extruded first sealant layer 11 (strand) is cut into granular shapes. In this way, the resin pellets 1 are formed.

[0239] Thereafter, the resin pellets are cooled (cooling step, reference numeral S9 in FIG. 5).

[0240] In this manner, the tube container 40 and the like are recycled, and the resin pellets 1 containing the recycled resin are obtained.

[0241] Next, a method for producing the tube container packaging material 10 will be described.

[0242] For example, when producing a tube container packaging material 10 shown in Fig. 2, first, a first sealant layer 11 is prepared. At this time, for example, a resin pellet 1 produced by the method shown in Fig. 5 is used as the first sealant layer 11, and a film may be produced by, for example, an inflation method.

[0243] A base layer 14 is also prepared. For example, a polyethylene terephthalate film or the like may be used as the base layer 14. Next, a release layer 12 is formed on the outer surface of the polyethylene terephthalate film. For example, a UV resin adhesive containing a gas generating agent is used as the material of the release layer 12. In this case, the release layer 12 may be formed by, for example, flexographic printing. Furthermore, a print layer is formed on the inner surface of the polyethylene terephthalate film.

[0244] Also, a barrier layer 15 is prepared. As the barrier layer 15, for example, an aluminum foil or the like may be used.

[0245] Furthermore, the second sealant layer 13 is prepared. As the second sealant layer 13, for example, a polyethylene film or the like may be used.

[0246] Next, the first sealant layer 11, the base layer 14, the barrier layer 15 and the second sealant layer 13 are laminated together by a dry lamination method, etc. In this manner, the tube container packaging material 10 shown in FIG.

[0247] As described above, according to the present embodiment, the tube container packaging material 10 includes the first sealant layer 11, the peeling layer 12, and the second sealant layer 13, which are arranged in this order from the outer surface 101 to the inner surface 102. In addition, at least 90% of the first sealant layer 11 is made of the same resin material. This allows the quality of the resin pellets 1 produced from the first sealant layer 11 of the tube container packaging material 10 to be stabilized. Furthermore, the peeling layer 12 is made of a material whose adhesion strength decreases when heated or exposed to light. This allows the first sealant layer 11 to be easily separated from the second sealant layer 13 by heating or exposing the tube container packaging material 10. Therefore, the first sealant layer 11 of the tube container packaging material 10 can be easily recycled. As a result, the environmental impact of the tube container packaging material 10 can be reduced. In particular, the first sealant layer 11 can be separated from the second sealant layer 13 by heating or exposing the peeling layer 12. For this reason, even if a layer (e.g., base layer 14 or barrier layer 15) made of a material different from the material constituting the first sealant layer 11 is provided between the peel layer 12 and the second sealant layer 13, only the first sealant layer 11 can be easily recycled.

[0248] Moreover, according to the present embodiment, the tube container packaging material 10 further includes a base material layer 14 provided between the peeling layer 12 and the second sealant layer 13. This can increase the strength of the entire tube container packaging material 10.

[0249] Moreover, according to this embodiment, the packaging material 10 for tube containers further includes a barrier layer 15 provided between the peeling layer 12 and the second sealant layer 13. This makes it possible to suppress the permeation of oxygen gas and the like in the tube container 40 produced from the packaging material 10 for tube containers, and effectively suppress weight loss and deterioration of the contents.

[0250] Furthermore, according to this embodiment, at least one of the first sealant layer 11 and the second sealant layer 13 contains a biomass-derived resin. In the tube container 40 produced from the tube container packaging material 10, the amount of fossil fuel used can be reduced. Therefore, the environmental impact of the tube container 40 can be reduced.

[0251] Further, according to the present embodiment, the method for producing the resin pellets 1 includes a step of recovering the tube container packaging material 10, a step of crushing the recovered tube container packaging material 10, a step of removing foreign matter from the crushed tube container packaging material 10 by stirring the crushed tube container packaging material 10 in water, a step of heating or exposing the crushed tube container packaging material 10 to light to reduce the adhesive force of the peeling layer 12 and thereby separating the first sealant layer 11 from the second sealant layer 13, a step of drying and selecting the first sealant layer 11 separated from the second sealant layer 13, a step of crushing the selected first sealant layer 11, a step of melting the crushed first sealant layer 11, a step of forming the resin pellets 1 from the melted first sealant layer 11, and a step of cooling the resin pellets 1. As a result, the resin pellets 1 contain recycled resin, and the environmental impact of the product (e.g., tube container 40) produced from the resin pellets 1 can be reduced. Moreover, at least 90% or more of the first sealant layer 11 for producing the resin pellets 1 is made of the same resin material. This makes it possible to stabilize the quality of products produced from the resin pellets 1. Furthermore, since at least 90% or more of the first sealant layer 11 is made of the same resin material, it makes it easier to recycle products produced from the resin pellets 1. EXAMPLES

[0252] Next, a specific example of the above embodiment will be described.

[0253] Example 1 A resin film (thickness: 180 μm) containing linear low-density polyethylene as a main component was prepared as the first sealant layer. The content of linear low-density polyethylene in the first sealant layer was 95%.

[0254] A polyethylene terephthalate film (thickness: 12 μm) was prepared as a base layer, and a print layer was formed on the inner surface of the polyethylene terephthalate film.

[0255] Next, a UV resin adhesive containing a gas generating agent (tetrazole) was applied to the outer surface of the polyethylene terephthalate film using a UV flexo coating machine as a release layer. After that, a release film (a silicone-coated release paper) was attached to the release layer.

[0256] In addition, as an intermediate layer, a polyethylene terephthalate film (thickness 12 μm) on which an aluminum vapor deposition film (barrier layer) was formed was prepared.

[0257] Furthermore, as a second sealant layer, a resin film (thickness: 80 μm) made of virgin resin of linear low-density polyethylene was prepared.

[0258] Next, the base layer, the intermediate layer and the second sealant layer were laminated together by dry lamination, after which the release film was peeled off from the release layer, and the first sealant layer was laminated on the release layer. The layer structure of the obtained packaging material for tube containers is as follows. LLDPE / peel layer / PET / print / adhesive layer / vapor deposition film / PET / adhesive layer / LLDPE In the above, "LLDPE" means a resin film containing linear low density polyethylene as the main component or a resin film made of virgin resin of linear low density polyethylene (hereinafter the same), and "PET" means a polyethylene terephthalate film (hereinafter the same).

[0259] Next, a tube container as shown in Fig. 4 was produced from the obtained laminate. At this time, high density polyethylene (HDPE) was used as the material for the head member.

[0260] Example 2 A packaging material for tube containers was prepared in the same manner as in Example 1, except that a release layer was used in which thermally expandable microcapsules (Kureha Microsphere, manufactured by Kureha Corporation) were mixed into an acrylic resin-based adhesive. The layer structure of the obtained packaging material for tube containers is as follows. LLDPE / peel layer / PET / print / adhesive layer / vapor deposition film / PET / adhesive layer / LLDPE

[0261] Next, a tube container as shown in Fig. 4 was produced from the obtained laminate. At this time, high density polyethylene (HDPE) was used as the material for the head member.

[0262] (Comparative Example) The thickness of the first sealant layer was 130 μm, no peeling layer was provided, and the second sealant layer was made of low-density polyethylene (density 0.92 g / cm 3 A packaging material for tube containers was produced in the same manner as in Example 2, except that a resin film (thickness 180 μm) made of virgin resin of (A) was used, and the first sealant layer and the base material layer were laminated together by a dry lamination method. The layer structure of the obtained packaging material for tube containers is as follows. LLDPE / adhesive layer / PET / print / adhesive layer / vapor deposition film / PET / adhesive layer / LDPE

[0263] Next, a tube container as shown in Fig. 4 was produced from the obtained laminate. At this time, high density polyethylene (HDPE) was used as the material for the head member.

[0264] (1) Recyclability evaluation Next, recyclability was evaluated. At this time, resin pellets were produced from each of the tube containers according to Example 1, Example 2, and Comparative Example by the method shown in FIG. 5. At this time, in the foreign matter removal step, the temperature of water in the mixer (manufactured by Shinto Scientific Co., Ltd. / general-purpose mixer, BL1200) was 50°C, the mixing speed was 200 rpm, and the mixing time was 30 minutes. In addition, when producing resin pellets from the tube container according to Example 1, ultraviolet rays were irradiated onto the peeling layer in the separation step. In addition, when producing resin pellets from the tube container according to Example 2 and the tube container according to Comparative Example, in the separation step, the heating temperature of the peeling layer was 120°C, and the heating time was 30 minutes. In addition, in the drying and sorting step, the drying temperature was 50°C, and the drying time was 180 minutes. In addition, in the melting step, the melting temperature was 190°C.

[0265] (2) Quality evaluation Next, the quality of the prepared resin pellets was evaluated by evaluating the melt flow rate (MFR), Charpy impact strength, tensile yield strength, flexural modulus, and odor of the resin pellets.

[0266] The melt flow rate (MFR) of the resin pellets was measured by Method A (mass measurement method) in accordance with JIS K7210-1:2014 under conditions of a temperature of 190°C and a load of 21.2N.

[0267] The Charpy impact strength of the resin pellets was measured using a Charpy impact tester (manufactured by Toyo Seiki Co., Ltd., product name: Charpy impact tester) in accordance with JIS K7111-1:2012. Specifically, first, a dumbbell-shaped test piece with a notch was prepared from each of the resin pellets prepared from the tube containers according to Example 1, Example 2, and Comparative Example. Next, the test piece was placed in the Charpy impact tester by supporting both ends of the test piece. Next, the test piece was destroyed by striking the test piece with a hammer from the opposite side of the notch. Then, the impact strength at which the test piece was destroyed was measured as the Charpy impact strength.

[0268] The tensile yield strength of the resin pellets was measured using a tensile tester (manufactured by Toyo Seiki Co., Ltd., product name "Universal Testing Machine / Tensile Tester 'Strograph VG'") in accordance with JIS K7161-1:2014. Specifically, first, dumbbell-shaped test pieces were prepared from the resin pellets prepared from the tube containers according to Example 1, Example 2, and Comparative Example. Next, the test pieces were placed in the tensile tester by chucking the vicinity of both ends in the longitudinal direction of the test pieces with the gripping members of the tensile tester. Next, the test pieces were pulled by moving the gripping members in the direction away from each other at a test speed of 300 mm / min. Then, the strength at which the test pieces broke was measured as the tensile yield strength.

[0269] The flexural modulus of the resin pellets was measured using a three-point bending tester (manufactured by Shimadzu Corporation, product name: fully automatic plastic tensile / bending tester) in accordance with JIS K7161-1:2014. Specifically, first, dumbbell-shaped test pieces were prepared from the resin pellets prepared from the tube containers according to Example 1, Example 2, and Comparative Example, and the test pieces were placed in the three-point bending tester. Next, the test pieces were deformed by applying pressure to the approximate center of the longitudinal direction of the test pieces. At this time, the load was applied so as to gradually increase from 0 N to 120 N. Then, the flexural modulus was calculated from the stress and strain amount when the test pieces were deformed.

[0270] The results are shown in Tables 3 and 4.

[0271] [Table 3]

[0272] [Table 4]

[0273] In the "Separability" column in Table 3, "good" means that the first sealant layer and the second sealant layer were easily separated, and "bad" means that the first sealant layer and the second sealant layer could not be separated.

[0274] In the "Moldability" column in Table 3, "good" means that the filter of the pelletizer was not clogged and the strands extruded in the pelletizer had a clean appearance, while "bad" means that the resin clogged the filter and resin pellets (strands) could not be formed.

[0275] In the "Appearance" column of Table 3, "good" means that the appearance of the resin pellet was smooth and no undissolved resin (so-called fish eyes) was visually observed, while "bad" means that undissolved resin (fish eyes) was visually observed.

[0276] In the "MFR" column in Table 4, "good" means that the melt flow rate was greater than 0.3 g / 10 min and less than 100 g / 10 min, and "bad" means that the melt flow rate was less than 0.3 g / 10 min.

[0277] In the "Charpy impact strength" column of Table 4, "good" means that the Charpy impact strength is 2.5 kJ / m 2 "Bad" means that the Charpy impact strength was 2.5 kJ / m or more. 2 This means that it was less than

[0278] In the "tensile yield strength" column in Table 4, "good" means that the tensile yield strength was 5.0 or more and less than 25.0 MPa, and "bad" means that the tensile yield strength was less than 5.0 MPa.

[0279] In the "flexural modulus" column in Table 4, "good" means that the flexural modulus was 100 MPa or more and less than 900 MPa, and "bad" means that the flexural modulus was 900 MPa or more.

[0280] In the "Odor" column in Table 4, "good" means that almost no residual odor was detected in the sensory evaluation, and "bad" means that a residual odor was detected in the sensory evaluation.

[0281] As a result, as shown in Tables 3 and 4, the tube container packaging materials according to Examples 1 and 2 achieved good results in all items. That is, the tube container packaging material according to this embodiment was able to maintain high quality of the recycled resin when the resin was recycled. Therefore, it was found that this embodiment can reduce the environmental load.

[0282] It is also possible to combine the multiple components disclosed in the above embodiments as necessary, or to delete some of the components disclosed in the above embodiments. [Explanation of symbols]

[0283] 1 Resin pellets 10. Packaging materials for tube containers 11 First sealant layer 12 Release layer 13 Second sealant layer 14 Base material layer 15 Barrier Layer 40 Tube Container 41 Body tube 42 one end 43 Head parts 101 Exterior 102 Inside

Claims

1. The sealant includes a first sealant layer, a release layer, and a second sealant layer, which are arranged in this order from the outer surface to the inner surface, At least 90% of the first sealant layer is made of the same resin-based material, The packaging material for tube containers, wherein the release layer is made of a material whose adhesive strength decreases when heated or exposed to light.

2. The packaging material for tube containers according to claim 1 , wherein the second sealant layer contains a material of the same resin system.

3. The packaging material for tube containers according to claim 1 , further comprising a base material layer provided between the release layer and the second sealant layer.

4. The packaging material for tube containers according to claim 1 , further comprising a barrier layer provided between the release layer and the second sealant layer.

5. The packaging material for tube containers according to claim 1 , wherein at least one of the first sealant layer and the second sealant layer contains a resin derived from biomass.

6. In a tube container, A body tube having the packaging material for a tube container according to any one of claims 1 to 5; a head member joined to one end of the body tube.

7. A method for producing resin pellets, comprising the steps of: A step of recovering the packaging material for tube containers according to any one of claims 1 to 5 or the tube container according to claim 6; A step of crushing the collected tube container packaging material or the tube container; a step of removing foreign matter from the crushed tube container packaging material or the crushed tube container by stirring the crushed tube container packaging material or the crushed tube container in water; a step of heating or exposing the crushed tube container packaging material or tube container to light to reduce the adhesive strength of the peel layer, thereby separating the first sealant layer from the second sealant layer; drying and screening the first sealant layer separated from the second sealant layer; pulverizing the selected first sealant layer; Melting the pulverized first sealant layer; forming a resin pellet from the molten first sealant layer; and cooling the resin pellets.

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