JP7605369B2 - Laminates, packaging materials - Google Patents

Description

The present invention relates to a laminate that has excellent recyclability and heat resistance and is suitable for food packaging, and to a packaging material obtained using the laminate.

Packaging materials used for packaging food and daily necessities are usually made of a laminate of a heat-sealable film such as unstretched polyethylene film or polypropylene film, and a resin film with excellent heat resistance and strength such as a polyester film or nylon film, bonded together with an adhesive (Patent Documents 1 and 2). Meanwhile, in recent years, with the growing demand for the creation of a recycling-oriented society, attempts have been made to recycle and reuse packaging materials. However, in laminates made of different types of resin films such as those mentioned above, it is difficult to separate the resins by type, making them unsuitable for recycling.

JP 2014-004799 A JP 2004-238050 A

A possible example of a laminate for packaging with excellent recyclability would be one that uses a stretched polyolefin film such as stretched polypropylene or stretched polyethylene film on the outer layer side from the contents, and an unstretched polypropylene film or low-density polyethylene film on the inner layer side (sealant film). Such a laminate has excellent recyclability compared to laminates using different types of base materials, since the olefin resin accounts for almost the entire laminate.

However, because olefin-based films have lower heat resistance than polyester or nylon films, laminates using stretched polyolefin films on the outer layer side will shrink if bags are made at the same heat sealing temperatures as when polyester or nylon films are used. To avoid this, bags must be made at lower temperatures than before, requiring longer heat sealing times, which reduces productivity.

The present invention has been made in consideration of this background, and aims to provide a laminate with excellent recyclability and heat resistance, and a packaging material using said laminate.

The present invention relates to a laminate comprising, in this order, a heat seal layer, a stretched polyolefin film, and a coating layer, the coating layer containing a composite resin (A) having a polysiloxane segment (a1) and a vinyl polymer segment (a2).

The laminate of the present invention can provide a laminate and packaging material with excellent heat resistance and recyclability.

<Laminate>
The laminate of the present invention has a heat seal layer, a stretched polyolefin film, and a coating layer in this order.

(Stretched polyolefin film)
Examples of oriented polyolefin films include high density polyethylene film (HDPE), uniaxially oriented polyethylene film (MDOPE), biaxially oriented polyethylene film (OPE), and biaxially oriented polypropylene film (OPP).

The thickness of the stretched polyolefin film can be adjusted appropriately depending on the purpose, but from the perspective of the balance between mechanical strength and processability, it is preferably 5 μm or more and 300 μm or less. More preferably, it is 7 μm or more and 100 μm or less.

The stretched polyolefin film may be surface-treated. This can improve adhesion to adjacent layers. The method of surface treatment is not particularly limited, and examples include physical treatments such as corona discharge treatment, ozone treatment, low-temperature plasma treatment using oxygen gas and/or nitrogen gas, and glow discharge treatment, as well as chemical treatments such as oxidation treatment using chemicals.

(Heat seal layer)
The heat seal layer is made of an olefin resin and has heat sealability, that is, it melts and fuses to each other by heat. Specific examples include films made of olefin resins such as polyethylene, such as low density polyethylene, medium density polyethylene, high density polyethylene, and linear low density polyethylene, polypropylene, ethylene-propylene copolymer, and polymethylpentene. The heat seal layer may be surface-treated by the same method as the stretched polyolefin film.

The thickness of the heat seal layer is preferably 15 μm or more and 500 μm or less, more preferably 20 μm or more and 250 μm or less, and even more preferably 30 μm or more and 100 μm or less. This makes it possible to improve the processability and puncture resistance of the laminate of the present invention while maintaining the heat sealability of the heat sealable resin layer.

(Coat layer)
The coating layer is provided directly on the stretched polyolefin film or via a printing layer described later. The coating layer is located as the outermost layer when viewed from the contents when the laminate of the present invention is made into a bag, and is the layer that comes into contact with the heat seal bar when the bag is made. The coating layer is a cured coating film of a coating agent containing a composite resin (A) having a polysiloxane segment (a1) and a vinyl polymer segment (a2). By disposing such a layer as the outermost layer of the laminate, the heat resistance of the laminate can be improved. The coating layer may be provided on the entire surface of the stretched polyolefin film, or may be provided partially only on the part that comes into contact with the heat seal bar when the laminate of the present invention is made into a bag and its periphery.

The polysiloxane segment (a1) is a segment obtained by condensing a silane compound having a silanol group and/or a hydrolyzable silyl group, and has a structural unit represented by the following general formula (1) and/or general formula (2) and a silanol group and/or a hydrolyzable silyl group. If the content of the polysiloxane segment (a1) is 10 to 90% by weight based on the total solid content of the composite resin (A), it is preferable because it facilitates bonding with the inorganic particles (m) described below.

R ¹ , R ² and R ³ in the above general formulas (1) and (2) each independently represent -R ⁴ -CH═CH ₂ , -R ⁴ -C(CH ₃ )═CH ₂ , -R ⁴ -O-CO-C(CH ₃ )═CH ₂ , and -R ⁴ -O-CO-CH═CH ₂ , or a group having a polymerizable double bond selected from the group consisting of groups represented by the following formula (3) (wherein R ⁴ represents a single bond or an alkylene group having 1 to 6 carbon atoms), an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 8 carbon atoms, an aryl group, an aralkyl group having 7 to 12 carbon atoms, or an epoxy group.

（一般式（３）中、ｎは１から５で表される整数であり、構造Ｑは、－ＣＨ＝ＣＨ_２または－Ｃ（ＣＨ_３）＝ＣＨ_２のいずれかを表す。）

(In the general formula (3), n is an integer of 1 to 5, and the structure Q represents either -CH= _CH2 or -C( _CH3 )= _CH2 .)

The structural units represented by the above general formula (1) and/or (2) are three-dimensional mesh-like polysiloxane structural units in which two or three of the silicon bonds are involved in crosslinking. Although they form a three-dimensional mesh structure, they do not form a dense mesh structure, so they do not gel and have good storage stability.

In the above general formulas (1) and (2), examples of the alkylene group having 1 to 6 carbon atoms in R ⁴ include a methylene group, an ethylene group, a propylene group, an isopropylene group, a butylene group, an isobutylene group, a sec-butylene group, a tert-butylene group, a pentylene group, an isopentylene group, a neopentylene group, a tert-pentylene group, a 1-methylbutylene group, a 2-methylbutylene group, a 1,2-dimethylpropylene group, a 1-ethylpropylene group, a hexylene group, a butyl ... Examples of the alkylene group include a silylene group, an isohexylene group, a 1-methylpentylene group, a 2-methylpentylene group, a 3-methylpentylene group, a 1,1-dimethylbutylene group, a 1,2-dimethylbutylene group, a 2,2-dimethylbutylene group, a 1-ethylbutylene group, a 1,1,2-trimethylpropylene group, a 1,2,2-trimethylpropylene group, a 1-ethyl-2-methylpropylene group, a 1-ethyl-1-methylpropylene group, etc. In view of the ease of availability of the raw material, a single bond or an alkylene group having 2 to 4 carbon atoms is preferred.

Examples of alkyl groups having 1 to 6 carbon atoms include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, neopentyl, tert-pentyl, 1-methylbutyl, 2-methylbutyl, 1,2-dimethylpropyl, 1-ethylpropyl, hexyl, isohexyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 1,1-dimethylbutyl, 1,2-dimethylbutyl, 2,2-dimethylbutyl, 1-ethylbutyl, 1,1,2-trimethylpropyl, 1,2,2-trimethylpropyl, 1-ethyl-2-methylpropyl, and 1-ethyl-1-methylpropyl.

Examples of cycloalkyl groups having 3 to 8 carbon atoms include cyclopropyl groups, cyclobutyl groups, cyclopentyl groups, and cyclohexyl groups.

Examples of the aryl group include a phenyl group, a naphthyl group, a 2-methylphenyl group, a 3-methylphenyl group, a 4-methylphenyl group, a 4-vinylphenyl group, and a 3-isopropylphenyl group.
Examples of the aralkyl group having 7 to 12 carbon atoms include a benzyl group, a diphenylmethyl group, and a naphthylmethyl group.

Furthermore, when at least one of R ¹ , R ² and R ³ is a group having a polymerizable double bond, the compound can be cured by active energy rays or the like. Due to the two curing mechanisms of active energy rays and a condensation reaction of a silanol group and/or a hydrolyzable silyl group, the crosslink density of the resulting cured product is increased, and a cured product having better abrasion resistance and low linear expansion can be formed, which is preferable.

The polysiloxane segment (a1) preferably has two or more groups having a polymerizable double bond, more preferably has 3 to 200 groups, and even more preferably has 3 to 50 groups. This allows a molded product with lower linear expansion to be obtained. Specifically, if the content of polymerizable double bonds in the polysiloxane segment (a1) is 3 to 35% by weight, the linear expansion coefficient can be designed to be lower than that of a stretched polyolefin film, and the heat resistance of the laminate can be improved. Here, the polymerizable double bond is a general term for a group that can undergo a growth reaction by a free radical, among vinyl groups, vinylidene groups, and vinylene groups. The content of polymerizable double bonds indicates the weight percentage of vinyl groups, vinylidene groups, or vinylene groups in the polysiloxane segment.

As the group having a polymerizable double bond, any known functional group containing a vinyl group, a vinylidene group, or a vinylene group can be used. Among them, a (meth)acryloyl group represented by -R ⁴ -C(CH ₃ )=CH ₂ or -R ⁴ -O-CO-C(CH ₃ )=CH ₂ is preferred because it has high reactivity during curing with active energy rays and has good compatibility with the vinyl polymer segment (a2) described below.

In addition, when the group having a polymerizable double bond is a group represented by the above general formula (3), the structure Q in the formula indicates that multiple vinyl groups may be bonded to the aromatic ring. For example, when two Qs are bonded to an aromatic ring, a structure such as the following structural formula (4) may also be included.

Since structures such as styryl groups do not contain oxygen atoms, they are less susceptible to oxidative decomposition originating from oxygen atoms and have high thermal decomposition resistance, making them suitable for applications requiring heat resistance. This is believed to be because the bulky structure inhibits oxidation reactions. In addition, in order to improve heat resistance, it is preferable to have a group having a polymerizable double bond selected from the group consisting of -R ⁴ -CH=CH ₂ and -R ⁴ -C(CH ₃ )=CH ₂ .

In the polysiloxane segment (a1), when at least one of R ¹ , R ^{2 ,} and R ³ in the above formula is an epoxy group, the polysiloxane segment (a1) can be cured by heat curing or active energy ray curing. Due to the two curing mechanisms of the condensation reaction of the epoxy group and the silanol group and/or the hydrolyzable silyl group, the crosslink density of the resulting cured product is increased, and a cured product having an excellent low linear expansion coefficient can be formed.

In this specification, a silanol group is a silicon-containing group having a hydroxyl group directly bonded to a silicon atom. Specifically, the silanol group is preferably a silanol group formed by bonding an oxygen atom having a bond to a hydrogen atom in a structural unit represented by general formula (1) and/or (2).

In this specification, a hydrolyzable silyl group refers to a silicon-containing group having a hydrolyzable group directly bonded to a silicon atom, and examples of such groups include those represented by the following general formula (5):

（式（６）中、Ｒ^５はアルキル基、アリール基又はアラルキル基等の１価の有機基を、Ｒ^６はハロゲン原子、アルコキシ基、アシロキシ基、フェノキシ基、アリールオキシ基、メルカプト基、アミノ基、アミド基、アミノオキシ基、イミノオキシ基及びアルケニルオキシ基からなる群から選ばれる加水分解性基である。またｂは０～２の整数である。）

(In formula (6), ^R5 is a monovalent organic group such as an alkyl group, an aryl group, or an aralkyl group, and ^R6 is a hydrolyzable group selected from the group consisting of a halogen atom, an alkoxy group, an acyloxy group, a phenoxy group, an aryloxy group, a mercapto group, an amino group, an amido group, an aminooxy group, an iminoxy group, and an alkenyloxy group. Also, b is an integer of 0 to 2.)

Examples of the alkyl group in ^R5 include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, an isopentyl group, a neopentyl group, a tert-pentyl group, a 1-methylbutyl group, a 2-methylbutyl group, a 1,2-dimethylpropyl group, a 1-ethylpropyl group, a hexyl group, an isohexyl group, a 1-methylpentyl group, a 2-methylpentyl group, a 3-methylpentyl group, a 1,1-dimethylbutyl group, a 1,2-dimethylbutyl group, a 2,2-dimethylbutyl group, a 1-ethylbutyl group, a 1,1,2-trimethylpropyl group, a 1,2,2-trimethylpropyl group, a 1-ethyl-2-methylpropyl group, and a 1-ethyl-1-methylpropyl group.
Examples of the aryl group include a phenyl group, a naphthyl group, a 2-methylphenyl group, a 3-methylphenyl group, a 4-methylphenyl group, a 4-vinylphenyl group, and a 3-isopropylphenyl group.
Examples of the aralkyl group include a benzyl group, a diphenylmethyl group, and a naphthylmethyl group.

In ^R6 , examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, a sec-butoxy group, and a tert-butoxy group.
Examples of the acyloxy group include formyloxy, acetoxy, propanoyloxy, butanoyloxy, pivaloyloxy, pentanoyloxy, phenylacetoxy, acetoacetoxy, benzoyloxy, and naphthoyloxy.
Aryloxy groups include, for example, phenyloxy, naphthyloxy, and the like.
Examples of the alkenyloxy group include a vinyloxy group, an allyloxy group, a 1-propenyloxy group, an isopropenyloxy group, a 2-butenyloxy group, a 3-butenyloxy group, a 2-pentenyloxy group, a 3-methyl-3-butenyloxy group, and a 2-hexenyloxy group.

By hydrolysis of the hydrolyzable group represented by ^R6 , the hydrolyzable silyl group represented by general formula (5) becomes a silanol group. Among them, a methoxy group and an ethoxy group are preferred because of their excellent hydrolyzability.
Specifically, the hydrolyzable silyl group is preferably a hydrolyzable silyl group in which an oxygen atom having a bond in a structural unit represented by general formula (1) and/or general formula (2) is bonded to or substituted with the hydrolyzable group.

Silanol groups and hydrolyzable silyl groups undergo a hydrolysis and condensation reaction between the hydroxyl groups in the silanol groups and the hydrolyzable groups in the hydrolyzable silyl groups, thereby increasing the crosslinking density of the polysiloxane structure and forming a cured product that has excellent abrasion resistance and low linear expansion.
It is also used when bonding a polysiloxane segment (a1) containing a silanol group or a hydrolyzable silyl group to a vinyl polymer segment (a2) described below via a bond represented by the following general formula (6).

The polysiloxane segment (a1) is not particularly limited except that it has a structural unit represented by general formula (1) and/or (2) and a silanol group and/or a hydrolyzable silyl group, and may contain other groups. For example, the polysiloxane segment (a1) may be a polysiloxane segment in which a structural unit in which R ¹ in the general formula (1) is a group having a polymerizable double bond and a structural unit in which R ¹ in the general formula (1) is an alkyl group such as methyl coexist; a structural unit in which R ¹ in the general formula (1) is a group having a polymerizable double bond, a structural unit in which R ¹ in the general formula (1) is an alkyl group such as methyl, and a structural unit in which R ² and R ³ in the general formula (2) are alkyl groups such as methyl, or a polysiloxane segment (a1) in which a structural unit in which R ¹ in the general formula (1) is a group having a polymerizable double bond and a structural unit in which R ² and R ³ in the general formula (2) are alkyl groups such as methyl.

The vinyl polymer segment (a2) is a polymer segment obtained by polymerizing a vinyl group or (meth)acrylic group-containing monomer, and examples of such segments include vinyl polymer segments, acrylic polymer segments, and vinyl/acrylic copolymer segments, which are preferably selected appropriately depending on the application. The composite resin (A) used in the present invention has the vinyl polymer segment (a2), and therefore has excellent adhesion to stretched polyolefin films.

The acrylic polymer segment is obtained, for example, by polymerizing or copolymerizing a general-purpose (meth)acrylic monomer. There are no particular limitations on the (meth)acrylic monomer, and examples thereof include alkyl (meth)acrylates having an alkyl group with 1 to 22 carbon atoms, such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and lauryl (meth)acrylate; aralkyl (meth)acrylates, such as benzyl (meth)acrylate and 2-phenylethyl (meth)acrylate; cyclohexyl (meth)acrylate; and the like. cycloalkyl (meth)acrylates such as 2-methoxyethyl (meth)acrylate and isobornyl (meth)acrylate; ω-alkoxyalkyl (meth)acrylates such as 2-methoxyethyl (meth)acrylate and 4-methoxybutyl (meth)acrylate; vinyl carboxylate esters such as vinyl acetate, vinyl propionate, vinyl pivalate and vinyl benzoate; alkyl esters of crotonic acid such as methyl crotonate and ethyl crotonate; and dialkyl esters of unsaturated dibasic acids such as dimethyl maleate, di-n-butyl maleate, dimethyl fumarate and dimethyl itaconate.

Specific examples of vinyl polymer segments include aromatic vinyl polymer segments, polyolefin polymers, and fluoroolefin polymers, and copolymers thereof may also be used. To obtain these vinyl polymers, vinyl group-containing monomers may be polymerized, and specifically, α-olefins such as ethylene, propylene, 1,3-butadiene, and cyclopentylethylene; vinyl compounds having aromatic rings such as styrene, 1-ethynyl-4-methylbenzene, divinylbenzene, 1-ethynyl-4-methylethylbenzene, benzonitrile, acrylonitrile, p-tert-butylstyrene, 4-vinylbiphenyl, 4-ethynylbenzyl alcohol, 2-ethynylnaphthalene, and phenanthrene-9-ethynyl; fluoroolefins such as vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, and chlorotrifluoroethylene are preferably used. More preferred are vinyl compounds having aromatic rings, such as styrene and p-tert-butylstyrene.

Examples of vinyl/acrylic copolymer segments include those obtained by copolymerizing these (meth)acrylic monomers with vinyl group-containing monomers.

There are no particular limitations on the polymerization method, solvent, or polymerization initiator used when copolymerizing the monomers, and the vinyl polymer segment (a2) can be obtained by a known method. For example, the vinyl polymer segment (a2) can be obtained by various polymerization methods such as bulk radical polymerization, solution radical polymerization, and non-aqueous dispersion radical polymerization using a polymerization initiator such as 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2-methylbutyronitrile), tert-butyl peroxypivalate, tert-butyl peroxybenzoate, tert-butyl peroxy-2-ethylhexanoate, di-tert-butyl peroxide, cumene hydroperoxide, or diisopropyl peroxycarbonate.

The number average molecular weight of the vinyl polymer segment (a2) is preferably in the range of 500 to 200,000, calculated as the number average molecular weight (hereinafter abbreviated as Mn), which can prevent thickening and gelation during the production of the composite resin (A) and provides excellent durability. Mn is more preferably in the range of 700 to 100,000, and even more preferably in the range of 1,000 to 50,000.

In this specification, the number average molecular weight of the vinyl polymer segment (a2) is a value measured by gel permeation chromatography (GPC) under the following conditions.
Measuring device: Gel permeation chromatograph GCP-244 (manufactured by WATERS)
Column: Shodex HFIP 80M x 2 (Showa Denko K.K.)
Solvent: dimethylformamide Flow rate: 0.5 ml/min
Temperature: 23℃
Sample concentration: 0.1% Solubility: Completely dissolved Filtration: Myshoridisk W-13-5
Injection volume: 0.300ml
Detector: R-401 type differential refractive index detector (WATERS)
Molecular weight calibration: Polystyrene (standard)

In order to form a composite resin (A) in which the vinyl polymer segment (a2) is bonded to the polysiloxane segment (a1) by a bond represented by the general formula (6), the vinyl polymer segment (a2) has a silanol group and/or a hydrolyzable silyl group bonded directly to a carbon atom. These silanol groups and/or hydrolyzable silyl groups become bonds represented by the general formula (6) in the composite resin (A), so they are hardly present in the vinyl polymer segment (a2) in the composite resin (A) which is the final product. However, there is no problem even if the silanol group and/or hydrolyzable silyl group remain in the vinyl polymer segment (a2), and when the composite resin (A) is cured, a hydrolysis condensation reaction proceeds between the hydroxyl group in the silanol group and the hydrolyzable group in the hydrolyzable silyl group, so that the crosslink density of the polysiloxane structure of the obtained cured product is increased, and a cured product with excellent heat resistance and abrasion resistance can be formed.

To introduce a silanol group and/or a hydrolyzable silyl group directly bonded to a carbon atom into the vinyl polymer segment (a2), specifically, when polymerizing the vinyl polymer segment (a2), a vinyl monomer containing a silanol group and/or a hydrolyzable silyl group directly bonded to a carbon bond may be used in combination with a vinyl group-polymerizing monomer and a (meth)acrylic monomer.

Examples of vinyl monomers containing silanol groups and/or hydrolyzable silyl groups directly bonded to carbon atoms include vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldimethoxysilane, vinyltri(2-methoxyethoxy)silane, vinyltriacetoxysilane, vinyltrichlorosilane, 2-trimethoxysilylethyl vinyl ether, 3-(meth)acryloyloxypropyltrimethoxysilane, 3-(meth)acryloyloxypropyltriethoxysilane, 3-(meth)acryloyloxypropylmethyldimethoxysilane, and 3-(meth)acryloyloxypropyltrichlorosilane. Among these, vinyltrimethoxysilane and 3-(meth)acryloyloxypropyltrimethoxysilane are preferred because they facilitate the hydrolysis reaction and allow the by-products after the reaction to be easily removed.

The vinyl polymer segment (a2) may have various functional groups. For example, a group having a polymerizable double bond, an epoxy group, an alcoholic hydroxyl group, an acidic group, etc., and the functional group can be introduced by blending a vinyl monomer having the corresponding functional group during polymerization. If the vinyl polymer segment (a2) has an acid group, it is preferable because the coating layer is more easily peeled off from the stretched polyolefin film when subjected to an alkali treatment described later.

Examples of vinyl monomers having an epoxy group include glycidyl (meth)acrylate, methyl glycidyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, vinylcyclohexene oxide, glycidyl vinyl ether, methyl glycidyl vinyl ether, and allyl glycidyl ether.

Examples of vinyl monomers having an alcoholic hydroxyl group include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, di-2-hydroxyethyl fumarate, mono-2-hydroxyethyl monobutyl fumarate, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, "PLACCEL FM or PLACCEL FA" [caprolactone addition monomer manufactured by Daicel Chemical Industries, Ltd.] and other hydroxyalkyl esters of various α,β-ethylenically unsaturated carboxylic acids, or adducts of these with ε-caprolactone.

Monomers containing acidic groups include acrylic acid, methacrylic acid, maleic acid, itaconic acid, citraconic acid, mesaconic acid, maleic anhydride, 4-methylcyclohex-4-ene-1,2-dicarboxylic anhydride, bicyclo[2.2.2]oct-5-ene-2,3-dicarboxylic anhydride, 1,2,3,4,5,8,9,10-octahydronaphthalene-2,3-dicarboxylic anhydride, 2-octa-1,3-diketospiro[4. 4] non-7-ene, bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic anhydride, maleopimaric acid, tetrahydrophthalic anhydride, methyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic anhydride, methyl-norbornene-5-ene-2,3-dicarboxylic anhydride, norborn-5-ene-2,3-dicarboxylic anhydride, sulfonated styrene, vinylbenzenesulfonamide, and the like.

The coating agent used to form the coat layer may contain inorganic particles (m) in addition to the composite resin (A). Furthermore, the composite resin (A) and the inorganic particles (m) may be bonded together. The composite resin (A) and the inorganic particles (m) can be bonded together via a siloxane bond in the polysiloxane segment (a1) of the composite resin (A). The presence of the inorganic particles (m) in the coat layer can further improve the heat resistance of the coat layer. In addition, the bond between the composite resin (A) and the inorganic particles (m) can be expected to make the coat layer more easily peelable from the stretched polyolefin film when subjected to an alkali treatment described later.

The inorganic particles (m) are not particularly limited as long as they do not impair the effects of the present invention, but when they are bonded to the polysiloxane segment (a1) via a siloxane bond, they are selected from those having a functional group capable of forming a siloxane bond. The functional group capable of forming a siloxane bond may be any functional group capable of forming a siloxane bond, such as a hydroxyl group, a silanol group, or an alkoxysilyl group. The functional group capable of forming a siloxane bond may be possessed by the inorganic particles (m) themselves, or the functional group may be introduced by modifying the inorganic particles (m). The method for modifying the inorganic particles (m) may be a known, commonly used method, such as a silane coupling agent treatment or coating with a resin having a functional group capable of forming a siloxane bond.

As inorganic particles (m), for example, alumina, magnesia, titania, zirconia, silica (quartz, fumed silica, precipitated silica, silicic anhydride, fused silica, crystalline silica, ultrafine amorphous silica, etc.), etc. are preferable because they have excellent heat resistance. Alternatively, boron nitride, aluminum nitride, alumina oxide, titanium oxide, magnesium oxide, zinc oxide, silicon oxide, etc. are preferable because they have excellent thermal conductivity. Inorganic particles (m) may be used alone or in combination of multiple types.

For example, when silica is used as the inorganic particles (m), known silica particles such as powdered silica and colloidal silica can be used without any particular limitation. Examples of commercially available powdered silica particles include Aerosil 50 and 200 manufactured by Nippon Aerosil Co., Ltd., Sildex H31, H32, H51, H52, H121, and H122 manufactured by Asahi Glass Co., Ltd., E220A and E220 manufactured by Nippon Silica Industry Co., Ltd., SYLYSIA 470 manufactured by Fuji Silysia Co., Ltd., and SG Flake manufactured by Nippon Sheet Glass Co., Ltd. Examples of commercially available colloidal silica include methanol silica sol, IPA-ST, PGM-ST, NBA-ST, XBA-ST, DMAC-ST, ST-UP, ST-OUP, ST-20, ST-40, ST-C, ST-N, ST-O, ST-50, and ST-OL, all of which are manufactured by Nissan Chemical Industries, Ltd.

Surface-modified silica particles may also be used, for example, the silica particles exemplified above that have been surface-treated with a reactive silane coupling agent having a hydrophobic group or modified with a compound having a (meth)acryloyl group. Commercially available powdered silica modified with a compound having a (meth)acryloyl group includes Aerosil RM50, R7200, R711, etc., manufactured by Nippon Aerosil Co., Ltd. Commercially available colloidal silica modified with a compound having a (meth)acryloyl group includes MIBK-SD, MEK-SD, etc., manufactured by Nissan Chemical Industries, Ltd. Colloidal silica surface-treated with a reactive silane coupling agent having a hydrophobic group includes MIBK-ST, MEK-ST, etc., manufactured by Nissan Chemical Industries, Ltd.

The shape of the silica particles is not particularly limited, and spherical, hollow, porous, rod-like, plate-like, fibrous, or amorphous silica particles can be used. For example, commercially available hollow silica particles such as Silinax manufactured by Nittetsu Mining Co., Ltd. can be used.

As titanium oxide particles, not only extender pigments but also ultraviolet light responsive photocatalysts can be used, such as anatase type titanium oxide, rutile type titanium oxide, and brookite type titanium oxide. Furthermore, particles designed to respond to visible light by doping different elements into the crystal structure of titanium oxide can also be used. Anionic elements such as nitrogen, sulfur, carbon, fluorine, and phosphorus, and cationic elements such as chromium, iron, cobalt, and manganese are preferably used as elements to be doped into titanium oxide. In addition, the form of the titanium oxide can be a powder, a sol dispersed in an organic solvent or water, or a slurry. Examples of commercially available powdered titanium oxide particles include Aerosil P-25 manufactured by Nippon Aerosil Co., Ltd. and ATM-100 manufactured by Teika Co., Ltd. In addition, examples of commercially available slurry-type titanium oxide particles include TKD-701 manufactured by Teika Co., Ltd.

The primary particle diameter of the inorganic particles (m) is preferably in the range of 5 to 200 nm. If it is 5 nm or more, the inorganic particles (m) in the dispersion are well dispersed, and if the diameter is within 200 nm, the strength of the cured product is good. More preferably, it is 10 nm to 100 nm. Note that the "particle diameter" referred to here is measured using a scanning electron microscope (TEM) or the like.

From the viewpoint of the balance between adhesion to the stretched polyolefin film and heat resistance, the inorganic particles (m) can be blended in a ratio of 5 to 90% by weight based on the total solid content of the composite resin (A) and the inorganic particles (m), and the blending amount can be changed as appropriate depending on the purpose. From the viewpoint of heat resistance, it is preferable that the blending amount of the inorganic particles (m) is 20% by mass or more based on the total solid content of the composite resin (A) and the inorganic particles (m).

When the composite resin (A) and the inorganic particles (m) are bonded together, the composite resin (A) can be obtained by a manufacturing method characterized by having step 1 of synthesizing a vinyl polymer segment (a2) having a silanol group and/or a hydrolyzable silyl group directly bonded to a carbon atom, step 2 of mixing an alkoxysilane with the inorganic particles (m), and step 3 of condensing the alkoxysilane. At this time, each step may be carried out separately or simultaneously. For example, the composite resin (A) can be produced by the following method.

<Method 1>
A method in which the vinyl polymer segment (a2) having a silanol group and/or a hydrolyzable silyl group directly bonded to a carbon atom obtained in step 1, a silane compound containing a silanol group and/or a hydrolyzable silyl group, and inorganic particles (m) are simultaneously mixed in step 2, and this mixture is subjected to condensation of the silane compound containing a silanol group and/or a hydrolyzable silyl group in step 3 to form a polysiloxane segment (a1) and a bond between the vinyl polymer segment (a2) and the inorganic particles (m).

<Method 2>
A method in which a silane compound containing a silanol group and/or a hydrolyzable silyl group is mixed with inorganic particles (m) in step 2, the silane compound containing a silanol group and/or a hydrolyzable silyl group is condensed in step 3 to form polysiloxane segments (a1) and inorganic particle bonds, and then the vinyl polymer segment (a2) having the silanol group and/or hydrolyzable silyl group obtained in step 1 is hydrolyzed and condensed again with the polysiloxane segment (a1) and the inorganic particles (m) in step 3 to form bonds.

Step 1 is a step of synthesizing a vinyl polymer segment (a2) having a silanol group and/or a hydrolyzable silyl group directly bonded to a carbon atom. To introduce a silanol group and/or a hydrolyzable silyl group directly bonded to a carbon atom into the vinyl polymer segment (a2), specifically, when polymerizing the vinyl polymer segment (a2), a vinyl monomer containing a silanol group and/or a hydrolyzable silyl group directly bonded to a carbon bond may be used in combination with a vinyl group polymerization monomer and a (meth)acrylic monomer.

Furthermore, after this, a silane compound containing a silanol group and/or a hydrolyzable silyl group may be hydrolyzed and condensed with the vinyl polymer segment (a2) to bond a polysiloxane segment precursor to the silanol group and/or the hydrolyzable silyl group directly bonded to the carbon atom.

Step 2 is a step of mixing a silane compound containing a silanol group and/or a hydrolyzable silyl group with inorganic particles (m). As the silane compound, a general-purpose silane compound containing a silanol group and/or a hydrolyzable silyl group, which will be described later, can be used. At this time, if there is a group to be introduced into the polysiloxane segment, a silane compound having the group to be introduced is used in combination. For example, when an aryl group is to be introduced, a silane compound having both an aryl group and a silanol group and/or a hydrolyzable silyl group may be used in combination as appropriate. Also, when a group having a polymerizable double bond is to be introduced, a silane compound having both a group having a polymerizable double bond and a silanol group and/or a hydrolyzable silyl group may be used in combination. In order to introduce an epoxy group into the resulting polysiloxane, an epoxy group-containing silane compound having both a silanol group and/or a hydrolyzable silyl group may be used at the same time.

For mixing, known dispersion methods can be used. Examples of mechanical means include dispersers, dispersers with stirring blades such as turbine blades, paint shakers, roll mills, ball mills, attritors, sand mills, and bead mills. To achieve uniform mixing, dispersion using a bead mill that uses dispersion media such as glass beads or zirconia beads is preferred.

Examples of bead mills include Star Mill manufactured by Ashizawa Finetech Co., Ltd.; MSC-MILL, SC-MILL, and Attritor MA01SC manufactured by Mitsui Mining Co., Ltd.; Nano Grain Mill, Pico Grain Mill, Pure Grain Mill, Mega Capper Grain Mill, Cera Power Grain Mill, Dual Grain Mill, AD Mill, Twin AD Mill, Basket Mill, and Twin Basket Mill manufactured by Asada Iron Works Co., Ltd.; and Apex Mill, Ultra Apex Mill, and Super Apex Mill manufactured by Kotobuki Industries Co., Ltd.

Step 3 is a step of condensing a silane compound containing a silanol group and/or a hydrolyzable silyl group. In step 3, the silane compound containing a silanol group and/or a hydrolyzable silyl group is condensed to form a siloxane bond. When the silanol group and/or the hydrolyzable silyl group of the polysiloxane segment (a1) and the silanol group and/or the hydrolyzable silyl group of the vinyl polymer segment (a2) undergo a dehydration condensation reaction, a bond represented by the general formula (6) is generated. Therefore, in the general formula (6), the carbon atom constitutes a part of the vinyl polymer segment (a2), and the silicon atom bonded only to the oxygen atom constitutes a part of the polysiloxane segment (a1). In addition, by condensing the silane compound containing a silanol group and/or a hydrolyzable silyl group with the inorganic particles (m) in a mixed state, a siloxane bond is formed between the silane compound containing a silanol group and/or a hydrolyzable silyl group and the inorganic particles (m), and the polysiloxane segment (a1) and the inorganic particles (m) are chemically bonded to each other.

In the composite resin (A), the bonding position between the polysiloxane segment (a1) and the vinyl polymer segment (a2) is arbitrary. Examples of the composite resin include a composite resin having a graft structure in which the polysiloxane segment (a1) is chemically bonded to the vinyl polymer segment (a2) as a side chain, and a composite resin having a block structure in which the vinyl polymer segment (a2) and the polysiloxane segment (a1) are chemically bonded.

As the silane compound containing a silanol group and/or a hydrolyzable silyl group used in steps 1 to 3, a general-purpose silane compound can be used. For example, various organotrialkoxysilanes such as methyltrimethoxysilane, methyltriethoxysilane, methyltri-n-butoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, iso-butyltrimethoxysilane, cyclohexyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, and 3-glycidoxypropyltriethoxysilane; various diorganodialkoxysilanes such as dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldi-n-butoxysilane, diethyldimethoxysilane, methylcyclohexyldimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 3-glycidoxypropylmethyldiethoxysilane; and chlorosilanes such as methyltrichlorosilane, ethyltrichlorosilane, vinyltrichlorosilane, dimethyldichlorosilane, and diethyldichlorosilane.

In addition, tetrafunctional alkoxysilane compounds such as tetramethoxysilane, tetraethoxysilane, or tetra-n-propoxysilane, or partial hydrolysis condensates of the tetrafunctional alkoxysilane compounds, can also be used in combination within a range that does not impair the effects of the present invention. When a tetrafunctional alkoxysilane compound or a partial hydrolysis condensate thereof is used in combination, it is preferable to use them in combination so that the silicon atoms of the tetrafunctional alkoxysilane compound do not exceed 20 mol% relative to the total silicon atoms constituting the polysiloxane segment (a1).

In addition, metal alkoxide compounds other than silicon atoms, such as boron, titanium, zirconium, or aluminum, can be used in combination as long as the effects of the present invention are not impaired. For example, it is preferable to use the above-mentioned metal alkoxide compounds in combination so that the metal atoms contained in the metal alkoxide compounds do not exceed 25 mol% relative to the total silicon atoms constituting the polysiloxane segment (a1).

In the silane compound containing silanol groups and/or hydrolyzable silyl groups used to form the polysiloxane segment (a1), if the monoalkyltrialkoxysilane having an alkyl group with 1 to 4 carbon atoms is 40 mol% or more, the hydrolysis and condensation of the polysiloxane segment (a1) is likely to proceed, and the bond becomes stronger, resulting in excellent heat resistance and being preferable. In the monoalkyltrialkoxysilane, it is preferable that the alkoxy group has 1 to 4 carbon atoms, and it is more preferable that the alkyl group has 1 to 2 carbon atoms.

Specific examples of monoalkyltrialkoxysilanes having an alkyl group with 1 to 4 carbon atoms include methyltrimethoxysilane, methyltriethoxysilane, methyltri-n-butoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltri-n-butoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n-butyltrimethoxysilane, and butyltriethoxysilane, with methyltrimethoxysilane being preferred.

In addition, examples of silane compounds having both a group having a polymerizable double bond and a silanol group and/or a hydrolyzable silyl group used when introducing a group having a polymerizable double bond include vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldimethoxysilane, vinyltri(2-methoxyethoxy)silane, vinyltriacetoxysilane, vinyltrichlorosilane, 2-trimethoxysilylethylvinylether, 3-(meth)acryloyloxypropyltrimethoxysilane, 3-(meth)acryloyloxypropyltriethoxysilane, 3-(meth)acryloyloxypropylmethyldimethoxysilane, and 3-(meth)acryloyloxypropyltrichlorosilane. Among these, vinyltrimethoxysilane and 3-(meth)acryloyloxypropyltrimethoxysilane are preferred because they can easily proceed with the hydrolysis reaction and can easily remove by-products after the reaction.

In addition, to introduce an epoxy group into the polysiloxane segment (a1), an epoxy group-containing silane compound may be used. Examples of epoxy group-containing silane compounds include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxyethoxysilane, γ-glycidoxypropyltriacetoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltriethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxyethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxyethoxysilane, β-(3,4-epoxycyclohexyl)ethyltriacet ... β-(3,4-epoxycyclohexyl)ethyldimethoxymethylsilane, β-(3,4-epoxycyclohexyl)ethyldiethoxymethylsilane, β-(3,4-epoxycyclohexyl)ethyldimethoxymethylsilane, β-(3,4-epoxycyclohexyl)ethyldiethoxymethylsilane, β-(3,4-epoxycyclohexyl)ethyldimethoxyethoxymethylsilane Dimethylsilane, β-(3,4-epoxycyclohexyl)ethyldiacetoxymethylsilane, γ-glycidoxypropyldimethoxyethylsilane, γ-glycidoxypropyldiethoxyethylsilane, γ-glycidoxypropyldimethoxyethoxyethylsilane, γ-glycidoxypropyldiacetoxyethylsilane, β-(3,4-epoxycyclohexyl)ethyldimethoxyethylsilane, β-(3,4-epoxycyclohexyl)ethyldiethoxyethylsilane, β-(3,4-epoxy β-(3,4-epoxycyclohexyl)ethyldimethoxyethoxyethylsilane, β-(3,4-epoxycyclohexyl)ethyldiacetoxyethylsilane, γ-glycidoxypropyldimethoxyisopropylsilane, γ-glycidoxypropyldiethoxyisopropylsilane, γ-glycidoxypropyldimethoxyethoxyisopropylsilane, γ-glycidoxypropyldiacetoxyisopropylsilane, β-(3,4-epoxycyclohexyl)ethyldiethoxyisopropylsilane, β-(3,4-epoxycyclohexyl)ethyldiethoxyisopropylsilane β-(3,4-epoxycyclohexyl)ethyldiethoxyisopropylsilane, β-(3,4-epoxycyclohexyl)ethyldimethoxyethoxyisopropylsilane, β-(3,4-epoxycyclohexyl)ethyldiacetoxyisopropylsilane, γ-glycidoxypropylmethoxydimethylsilane, γ-glycidoxypropylethoxydimethylsilane, γ-glycidoxypropylmethoxyethoxydimethylsilane, γ-glycidoxypropylacetoxydimethylsilane, β-(3,4-epoxycyclo β-(3,4-epoxycyclohexyl)ethyl methoxydimethyl silane, β-(3,4-epoxycyclohexyl)ethyl ethoxy dimethyl silane, β-(3,4-epoxycyclohexyl)ethyl methoxyethoxy dimethyl silane, β-(3,4-epoxycyclohexyl)ethyl acetoxy dimethyl silane, γ-glycidoxypropyl methoxydiethyl silane, γ-glycidoxypropyl ethoxydiethyl silane, γ-glycidoxypropyl methoxyethoxydiethyl silane, γ-glycidoxypropyl acetoxydiethyl silane Tylsilane, β-(3,4-epoxycyclohexyl)ethyl methoxydiethylsilane, β-(3,4-epoxycyclohexyl)ethyl ethoxydiethylsilane, β-(3,4-epoxycyclohexyl)ethyl methoxyethoxydiethylsilane, β-(3,4-epoxycyclohexyl)ethyl acetoxydiethylsilane, γ-glycidoxypropyl methoxydiisopropylsilane, γ-glycidoxypropyl ethoxydiisopropylsilane, γ-glycidoxypropyl methoxyethoxydiisopropylsilane Isopropyl silane, γ-glycidoxypropyl acetoxydiisopropyl silane, β-(3,4-epoxycyclohexyl)ethyl methoxydiisopropyl silane, β-(3,4-epoxycyclohexyl)ethyl ethoxydiisopropyl silane, β-(3,4-epoxycyclohexyl)ethyl methoxyethoxydiisopropyl silane, β-(3,4-epoxycyclohexyl)ethyl acetoxydiisopropyl silane, γ-glycidoxypropyl methoxyethoxymethyl silane, γ-glycidoxypropyl methoxyethoxymethyl silane, glycidoxypropyl acetoxy methoxymethyl silane, γ-glycidoxypropyl acetoxy ethoxy methyl silane, β-(3,4-epoxycyclohexyl) ethyl methoxyethoxy methyl silane, β-(3,4-epoxycyclohexyl) ethyl methoxyacetoxy methyl silane, β-(3,4-epoxycyclohexyl) ethyl ethoxy acetoxy methyl silane, γ-glycidoxypropyl methoxyethoxy ethyl silane, γ-glycidoxypropyl acetoxy methoxyethyl silane, γ -glycidoxypropyl acetoxyethoxyethyl silane, β-(3,4-epoxycyclohexyl)ethyl methoxyethoxyethyl silane, β-(3,4-epoxycyclohexyl)ethyl methoxyacetoxyethyl silane, β-(3,4-epoxycyclohexyl)ethyl ethoxyacetoxyethyl silane, γ-glycidoxypropyl methoxyethoxyisopropyl silane, γ-glycidoxypropyl acetoxymethoxyisopropyl silane, γ-glycidoxypropyl acetoxyethoxy Isopropylsilane, β-(3,4-epoxycyclohexyl)ethylmethoxyethoxyisopropylsilane, β-(3,4-epoxycyclohexyl)ethylmethoxyacetoxyisopropylsilane, β-(3,4-epoxycyclohexyl)ethylethoxyacetoxyisopropylsilane, glycidoxymethyltrimethoxysilane, glycidoxymethyltriethoxysilane, α-glycidoxyethyltrimethoxysilane, α-glycidoxymethyltrimethoxysilane, β-glycidoxyethyl glycidoxypropyltrimethoxysilane, β-glycidoxymethyltrimethoxysilane, α-glycidoxypropyltrimethoxysilane, α-glycidoxypropyltriethoxysilane, β-glycidoxypropyltrimethoxysilane, β-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltripropoxysilane, γ-glycidoxypropyltributoxysilane, γ-glycidoxypropyltriphenoxysilane, α-glycidoxybutyltrimethoxysilane, α-glycidoxybutyltri Ethoxysilane, β-glycidoxybutyltrimethoxysilane, β-glycidoxybutyltriethoxysilane, γ-glycidoxybutyltrimethoxysilane, γ-glycidoxybutyltriethoxysilane, (3,4-epoxycyclohexyl)methyltrimethoxysilane, (3,4-epoxycyclohexyl)methyltriethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrippropoxysilane, β-(3,4-epoxycyclohexyl)ethyltriptoxysilane, β-(3, 4-epoxycyclohexyl)ethyltriphenoxysilane, γ-(3,4-epoxycyclohexyl)propyltrimethoxysilane, γ-(3,4-epoxycyclohexyl)propyltriethoxysilane, δ-(3,4-epoxycyclohexyl)butyltrimethoxysilane, δ-(3,4-epoxycyclohexyl)butyltriethoxysilane, glycidoxymethylmethyldimethoxysilane, glycidoxymethylmethyldiethoxysilane, α-glycidoxyethylmethyldimethoxysilane , α-glycidoxyethyl methyl diethoxysilane, β-glycidoxyethyl methyl dimethoxysilane, β-glycidoxyethyl methyl diethoxysilane, α-glycidoxypropyl methyl dimethoxysilane, α-glycidoxypropyl methyl diethoxysilane, β-glycidoxypropyl methyl dimethoxysilane, β-glycidoxypropyl methyl diethoxysilane, γ-glycidoxypropyl methyl dimethoxysilane, γ-glycidoxypropyl methyl diethoxysilane, γ-glycidoxypropyl methyl diethoxysilane Examples of the silane include propyl methyl dipropoxy silane, γ-glycidoxy propyl methyl dibutoxy silane, γ-glycidoxy propyl methyl dimethoxy ethoxy silane, γ-glycidoxy propyl methyl diphenoxy silane, γ-glycidoxy propyl ethyl dimethoxy silane, γ-glycidoxy propyl ethyl diethoxy silane, γ-glycidoxy propyl ethyl dipropoxy silane, γ-glycidoxy propyl vinyl dimethoxy silane, and γ-glycidoxy propyl vinyl diethoxy silane.

In addition, to introduce a group represented by formula (3) into the polysiloxane segment (a1), a silane compound having a group represented by formula (3) may be used. Specific examples of silane compounds having a group represented by formula (3) include p-styryltrimethoxysilane and p-styryltriethoxysilane.

In step 2, a part or all of the silane compound containing silanol groups and/or hydrolyzable silyl groups to be mixed with the inorganic particles (m) may be hydrolyzed and condensed. Furthermore, a dispersion medium may be used for the purpose of adjusting the solid content and viscosity. The dispersion medium may be any liquid medium that does not impair the effects of the present invention, and examples of the dispersion medium include various organic solvents, water, liquid organic polymers, and monomers.

Examples of organic solvents include ketones such as acetone, methyl ethyl ketone (MEK), and methyl isobutyl ketone (MIBK); cyclic ethers such as tetrahydrofuran (THF) and dioxolane; esters such as methyl acetate, ethyl acetate, and butyl acetate; aromatics such as toluene and xylene; and alcohols such as carbitol, cellosolve, methanol, isopropanol, butanol, propylene glycol monomethyl ether, and normal propyl alcohol, which can be used alone or in combination.

The coating agent used in the present invention may contain, in addition to the composite resin (A), a polymer or monomer having a reactive group that directly contributes to the curing reaction with the composite resin (A).

When using polyisocyanate as a reactive compound, it is preferable that the vinyl polymer segment (a2) in the composite resin (A) has an alcoholic hydroxyl group. In this case, it is preferable that the polyisocyanate is contained in an amount of 5 to 50% by weight based on the total amount of the composite resin (A). By containing the polyisocyanate in this range, the conformity of the coating layer when the stretched polyolefin film is deformed is improved. This is presumed to be because the polyisocyanate reacts with the hydroxyl group in the system (which is the hydroxyl group in the vinyl polymer segment (a2) or the hydroxyl group in the active energy ray curable monomer having an alcoholic hydroxyl group described later), forming a urethane bond, which is a soft segment, and acts to relieve the concentration of stress due to hardening derived from the polymerizable double bond. There is no particular limitation on the polyisocyanate used, and any known polyisocyanate can be used.

From the viewpoint of conformality of the coating layer, it is preferable that the isocyanate groups in the polyisocyanate are 3 to 30% by weight. If the isocyanate groups in the polyisocyanate exceed 30%, the effect of improving conformality due to stress relaxation may not be achieved.

The reaction between the polyisocyanate and the hydroxyl groups in the system (these are the hydroxyl groups in the vinyl polymer segment (a2) and the hydroxyl groups in the active energy ray-curable monomer having an alcoholic hydroxyl group, described below) does not require heating, and the reaction proceeds gradually by leaving the mixture at room temperature. If necessary, the mixture may be heated at 80°C for several minutes to several hours (20 minutes to 4 hours) to promote the reaction between the alcoholic hydroxyl groups and the isocyanate. In this case, a known urethanization catalyst may be used if necessary. The urethanization catalyst is selected appropriately depending on the desired reaction temperature.

When an active energy ray-curable monomer is used as the reactive compound, it is preferable to use a polyfunctional vinyl monomer having multiple vinyl reactive groups. There are no particular limitations on the polyfunctional vinyl monomer, and known polyfunctional vinyl monomers such as polyfunctional vinyl monomers and polyfunctional (meth)acrylic monomers can be used. For example, 1,2-ethanediol diacrylate, 1,2-propanediol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, dipropylene glycol diacrylate, neopentyl glycol diacrylate, tripropylene glycol diacrylate, trimethylolpropane diacrylate, trimethylolpropane triacrylate, tris(2-acryloyloxy)isocyanurate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, di(trimethylolpropane)tetraacrylate, di(pentaerythritol)pentaacrylate, di(pentaerythritol)hexaacrylate, and other polyfunctional (meth)acrylates having two or more polymerizable double bonds in one molecule can be mentioned. In addition, urethane acrylate, polyester acrylate, epoxy acrylate, and the like can also be exemplified as polyfunctional acrylates. These may be used alone or in combination of two or more.

For example, when the above-mentioned polyisocyanate is used in combination, acrylates having a hydroxyl group, such as pentaerythritol triacrylate and dipentaerythritol pentaacrylate, are preferred.
For the purpose of improving abrasion resistance, it is preferable to use a polyvalent (meth)acrylate having an isocyanurate structure. Specific examples thereof include tris(2-acryloyloxyethyl)isocyanurate, ε-caprolactone-modified tris(2-acryloyloxyethyl)isocyanurate, and isocyanuric acid EO-modified diacrylate.

As a reactive compound, monofunctional vinyl monomers can also be used in combination. For example, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, caprolactone-modified hydroxy (meth)acrylate (for example, trade name "Placcel" manufactured by Daicel Chemical Industries, Ltd.), mono(meth)acrylate of polyester diol obtained from phthalic acid and propylene glycol, mono(meth)acrylate of polyester diol obtained from succinic acid and propylene glycol, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, pentaerythritol tri(meth)acrylate, 2-hydroxy-3-(meth)acryloyloxypropyl (meth)acrylate, various epoxy esters. Examples of the monomers include hydroxyl group-containing (meth)acrylic acid esters such as (meth)acrylic acid adducts of (meth)acrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, and other carboxyl group-containing vinyl monomers, vinyl sulfonic acid, styrene sulfonic acid, sulfoethyl (meth)acrylate, and other sulfonic acid group-containing vinyl monomers, 2-(meth)acryloyloxyethyl acid phosphate, 2-(meth)acryloyloxypropyl acid phosphate, 2-(meth)acryloyloxy-3-chloro-propyl acid phosphate, 2-methacryloyloxyethylphenyl phosphoric acid, and other acidic phosphate ester-based vinyl monomers, and vinyl monomers having a methylol group such as N-methylol (meth)acrylamide. These monomers may be used alone or in combination.

From the viewpoint of the heat resistance of the laminate, when using an active energy ray curable monomer as a reactive compound, it is preferable to use one with a glass transition temperature of -30°C or higher. The upper limit of the glass transition temperature is not particularly limited, but as an example, it is 250°C or lower. When two or more active energy ray curable monomers are used in combination, the glass transition temperature of the reactive compound is the value obtained by converting the temperature (K) calculated by the Fox formula below into Celsius temperature (°C). In the formula below, W1, W2, W3, and W4 mean the mass fraction (mass%) of each component. In addition, Tg1, Tg2, Tg3, and Tg4 mean the glass transition temperature (K) of the homopolymer of each component.

When an epoxy group is contained, a known curing agent for epoxy resins can be used as a reactive compound, such as phenol novolac resin, cresol novolac resin, aromatic hydrocarbon formaldehyde resin modified phenol resin, dicyclopentadiene phenol addition type resin, phenol aralkyl resin (Zylok resin), naphthol aralkyl resin, trimethylolmethane resin, tetraphenylolethane resin, naphthol novolac resin, naphthol-phenol co-condensed novolac resin, naphthol-cresol co-condensed novolac resin, biphenyl modified phenol resin (a polyhydric phenol compound in which phenol nuclei are linked by bismethylene groups), biphenyl modified naphthol resin (a polyhydric naphthol compound in which phenol nuclei are linked by bismethylene groups), aminotriazine modified phenol resin (melamine, benzoguanamine, etc.) phenolic compounds such as polyhydric phenol compounds in which a phenol nucleus is linked by a carboxyl group) and alkoxy group-containing aromatic ring modified novolak resins (polyhydric phenol compounds in which a phenol nucleus and an alkoxy group-containing aromatic ring are linked by a formaldehyde); acid anhydride compounds such as phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride; amide compounds such as dicyandiamide and polyamide resins synthesized from a dimer of linoleic acid and ethylenediamine; and amine compounds such as diaminodiphenylmethane, diethylenetriamine, triethylenetetramine, diaminodiphenylsulfone, isophoronediamine, imidazole, BF3-amine complex, and guanidine derivatives.

It is also preferable to use a polymer or monomer capable of introducing an acidic group into the coating layer as the reactive compound. This is expected to have the effect of making the coating layer easier to peel off from the stretched polyolefin film when subjected to an alkali treatment described below. Examples of such reaction products include acrylic acid, methacrylic acid, maleic acid, itaconic acid, citraconic acid, mesaconic acid, maleic anhydride, 4-methylcyclohex-4-ene-1,2-dicarboxylic anhydride, bicyclo[2.2.2]oct-5-ene-2,3-dicarboxylic anhydride, 1,2,3,4,5,8,9,10-octahydronaphthalene-2,3-dicarboxylic anhydride, 2-octa-1,3-diketospiro[4.4 ]non-7-ene, bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic anhydride, maleopimaric acid, tetrahydrophthalic anhydride, methyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic anhydride, methyl-norbornene-5-ene-2,3-dicarboxylic anhydride, norborn-5-ene-2,3-dicarboxylic anhydride, sulfonated styrene, vinylbenzenesulfonamide, and the like.

It is also preferable to use a polymer or monomer capable of introducing an ether skeleton into the coating layer as the reactive compound. This is expected to make it easier for the coating layer to be peeled off from the stretched polyolefin film when subjected to the alkali treatment described below.

The average number of functional groups in the reactive compound can be adjusted as appropriate, but is preferably 2 to 6. This allows the coating layer to be designed with a low linear expansion coefficient, improving the heat resistance of the laminate.

When a reactive compound is used, the amount used is preferably 1 to 85% by weight, more preferably 5 to 80% by weight, of the total solid content of the coating agent containing the composite resin (A). By using the reactive compound within the above range, it is possible to adjust the adhesion of the coating layer to the stretched polyolefin film and the heat resistance of the laminate.

If necessary, in addition to the reactive compounds, a curing accelerator can be used in combination. Various types of curing accelerators can be used, including phosphorus compounds, tertiary amines, imidazoles, organic acid metal salts, Lewis acids, and amine complex salts. In particular, the imidazole compound 2-ethyl-4-methylimidazole, the phosphorus compound triphenylphosphine, and the tertiary amine 1,8-diazabicyclo-[5.4.0]-undecene (DBU) are preferred because of their excellent curing properties, heat resistance, electrical properties, and moisture resistance reliability.

A dispersion medium may be used to adjust the solid content and viscosity of the coating agent used in the present invention. The dispersion medium may be any liquid medium that does not impair the effects of the present invention, and examples of the dispersion medium include various aqueous solvents, organic solvents, and liquid organic polymers.

Examples of organic solvents include ketones such as acetone, methyl ethyl ketone (MEK), and methyl isobutyl ketone (MIBK); cyclic ethers such as tetrahydrofuran (THF) and dioxolane; esters such as methyl acetate, ethyl acetate, and butyl acetate; aromatics such as toluene and xylene; and alcohols such as carbitol, cellosolve, methanol, isopropanol, butanol, propylene glycol monomethyl ether, and normal propyl alcohol. These can be used alone or in combination, but of these, methyl ethyl ketone is preferred from the standpoint of volatility during coating and solvent recovery.

Liquid organic polymers are liquid organic polymers that do not directly contribute to the curing reaction, and examples include carboxyl group-containing modified polymers (Floren G-900, NC-500: Kyoeisha), acrylic polymers (Floren WK-20: Kyoeisha), amine salts of special modified phosphate esters (HIPLAAD ED-251: Kusumoto Chemical), and modified acrylic block copolymers (DISPERBYK2000; BYK-Chemie).

The coating agent may also contain other catalysts, polymerization initiators, organic fillers, inorganic fillers, organic solvents, inorganic pigments, organic pigments, extender pigments, clay minerals, waxes, surfactants, stabilizers, flow adjusters, dyes, leveling agents, rheology control agents, ultraviolet absorbers, antioxidants, plasticizers, etc.

The coating layer is formed by applying the above-mentioned coating agent directly or through a printing layer onto the stretched polyolefin film and drying it. It is more preferable to harden the coating agent using the reactive functional groups of the composite resin (A) and the inorganic particles (m). The hardening method is appropriately selected depending on the reactive functional groups of the composite resin (A) and the inorganic particles (m).

There are no particular limitations on the method of applying the coating agent, and any conventionally known method can be used. Examples include various coating methods such as spray coating, direct gravure coating, gravure kiss reverse coating, offset gravure coating, flexo coating, offset coating, bar coating, roll kiss coating, positive rotation roll coating, reverse roll coating, slot die coating, vacuum die coating, (micro)chamber doctor coating, air doctor coating, blade coating, knife coating, spin coating, and dipping coating.

The thickness of the coating layer can be adjusted as appropriate, but from the viewpoint of heat resistance, it is preferable that it be 0.3 μm or more. From the viewpoint of adhesion, it is preferable that it be 6 μm or less.

The coating agent used in the present invention can be thermally cured, for example, via the silanol groups and/or hydrolyzable silyl groups of the polysiloxane segment (a1) of the composite resin (A). In thermal curing, it is possible to heat and cure the compound alone, but it is also possible to use a curing catalyst in combination. Examples of curing catalysts include inorganic acids such as hydrochloric acid, sulfuric acid, and phosphoric acid; organic acids such as p-toluenesulfonic acid, monoisopropyl phosphate, and acetic acid; inorganic bases such as sodium hydroxide and potassium hydroxide; titanate esters such as tetraisopropyl titanate and tetrabutyl titanate; 1,8-diazabicyclo[5.4.0]undecene-7 (DBU), 1,5-diazabicyclo[4.3.0]nonene-5 (DBN), 1,4-diazabicyclo[2.2.2]octane (DABCO), tri-n-butylamine, dimethylbenzylamine, monoethanolamine, isopropylamine, butyl ... Examples of the catalyst include various compounds containing a basic nitrogen atom, such as midazole and 1-methylimidazole; various quaternary ammonium salts, such as tetramethylammonium salt, tetrabutylammonium salt, and dilauryldimethylammonium salt, which have a counter anion such as chloride, bromide, carboxylate, or hydroxide; and tin carboxylates, such as dibutyltin diacetate, dibutyltin dioctoate, dibutyltin dilaurate, dibutyltin diacetylacetonate, tin octylate, and tin stearate. The catalyst may be used alone or in combination of two or more kinds.

When the vinyl polymer segment (a2) contains an alcoholic hydroxyl group and the composition further contains an isocyanate group-containing compound, a urethanization reaction can be caused by adding a catalyst.
When the vinyl polymer segment (a2) or the polysiloxane segment (a1) has a group having a polymerizable double bond, the reaction can be carried out by using a thermal polymerization initiator.
In addition, when the vinyl polymer segment (a2) or the polysiloxane segment (a1) has an epoxy group, a compound having an epoxy group, a hydroxyl group, a carboxyl group, an acid anhydride, or an amide group can be blended to cause a reaction, and a general-purpose curing agent for epoxy resins can be used.

It is also possible to use the composite resin (A) in combination with a thermosetting resin. Examples of thermosetting resins include vinyl resins, unsaturated polyester resins, polyurethane resins, epoxy resins, epoxy ester resins, acrylic resins, phenolic resins, petroleum resins, ketone resins, silicone resins, and modified resins of these resins.

In the composite resin (A), when the vinyl polymer segment (a2) or the polysiloxane segment (a1) has a polymerizable unsaturated group, it can also be cured by active energy ray curing. More specifically, photocuring is possible by blending a photopolymerization initiator with the coating agent. For photocuring, ultraviolet curing is preferred. As the photopolymerization initiator, a known one may be used, and for example, one or more selected from the group consisting of acetophenones, benzyl ketals, and benzophenones can be preferably used. Examples of acetophenones include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, and 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone. Examples of benzyl ketals include 1-hydroxycyclohexyl-phenyl ketone and benzyl dimethyl ketal. Examples of the benzophenones include benzophenone, o-benzoyl methyl benzoate, etc. Examples of the benzoins include benzoin, benzoin methyl ether, benzoin isopropyl ether, etc. The photopolymerization initiators may be used alone or in combination of two or more kinds.

When UV curing is used, polyfunctional (meth)acrylates may be added as necessary to improve the curing density and therefore the heat resistance. Monofunctional (meth)acrylates may also be used.

The light used for UV curing can be, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a metal halide lamp, a xenon lamp, an argon laser, a helium-cadmium laser, an ultraviolet light-emitting diode, etc.

Alternatively, an electron beam (electron beam) in which electrons are artificially accelerated by an accelerator can be used as the active energy ray, and the coating layer can be formed by electron beam curing. When the coating layer is formed by electron beam curing, the coating agent does not contain a photopolymerization initiator.

When forming a coating layer by electron beam curing, it is also preferable to use a polyfunctional or monofunctional (meth)acrylate as a reactive compound in addition to the composite resin (A).

It is preferable that the energy intensity of the electron beam used for electron beam curing is 30,000 to 300,000 eV and the exposure dose is 5 to 100 kGy·m/min. (kilogray).

The coating layer is preferably formed by curing the above-mentioned coating agent by active energy ray curing, and more preferably by electron beam curing. When electron beam curing is used, the coating layer does not contain a photopolymerization initiator, so that an odorless or odor-suppressed laminate can be obtained, and there is no concern that the photopolymerization initiator will migrate to the contents when the laminate of the present invention is used as a food packaging material. In addition, in the case of electron beam curing, the effect of heat on the irradiated object is small, so that distortion, wrinkles, deformation, etc. due to heat hardly occur, and processing at a line speed of 10 to 400 m/min or more is possible.

Furthermore, when a coating agent is applied so as to come into contact with the stretched polyolefin film and then cured with electron beams to form a coating layer, the adhesion between the stretched polyolefin film and the coating layer is improved. This effect is more pronounced when the composite resin (A) has a methacryloyl group or is used in combination with an active energy ray curable monomer having a methacryloyl group. Therefore, when a printing layer, which will be described later, is provided between the stretched polyolefin film and the coating layer, it is preferable to provide the printing layer partially, rather than entirely, on the stretched polyolefin film so that there is an area where the stretched polyolefin film and the coating layer come into contact.

(Adhesive Layer)
The stretched polyolefin film and the heat seal layer can be bonded together by any method, but as an example, they can be bonded together using a two-component curing adhesive containing a polyol composition and a polyisocyanate composition. In this specification, the cured coating film of the two-component curing adhesive is referred to as the adhesive layer.

The polyol composition includes a polyol having multiple hydroxyl groups. Examples of such polyols include glycols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, dimethylbutanediol, butylethylpropanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, bishydroxyethoxybenzene, 1,4-cyclohexanediol, and 1,4-cyclohexanedimethanol;

Trifunctional or tetrafunctional aliphatic alcohols such as glycerin, trimethylolpropane, and pentaerythritol;
Bisphenols such as bisphenol A, bisphenol F, hydrogenated bisphenol A, and hydrogenated bisphenol F;
Dimer diol;
polyether polyols obtained by addition polymerization of alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, tetrahydrofuran, and cyclohexylene in the presence of a polymerization initiator such as the glycols or trifunctional or tetrafunctional aliphatic alcohols;
a polyether urethane polyol obtained by further polymerizing a polyether polyol with the aromatic or aliphatic polyisocyanate;

Polyester polyols (1) which are reaction products of polyesters obtained by ring-opening polymerization of cyclic ester compounds such as propiolactone, butyrolactone, ε-caprolactone, σ-valerolactone, β-methyl-σ-valerolactone, etc., with polyhydric alcohols such as the above-mentioned glycols, glycerin, trimethylolpropane, pentaerythritol, etc.;
Polyester polyol (2) obtained by reacting a difunctional polyol such as the glycol, dimer diol, or bisphenol with a polycarboxylic acid:
(3) a polyester polyol obtained by reacting a trifunctional or tetrafunctional aliphatic alcohol with a polycarboxylic acid;
(4) a polyester polyol obtained by reacting a difunctional polyol with the trifunctional or tetrafunctional aliphatic alcohol and a polycarboxylic acid;
Polyester polyols (5), which are polymers of hydroxyl acids such as dimethylolpropionic acid and castor oil fatty acid;

polyester polyether polyols obtained by reacting any one of the polyester polyols (1) to (5) and the polyether polyols with an aromatic or aliphatic polyisocyanate;
polyester polyurethane polyols obtained by polymerizing the polyester polyols (1) to (5) with aromatic or aliphatic polyisocyanates;
Examples of the polyol include castor oil-based polyols such as castor oil, dehydrated castor oil, hydrogenated castor oil, and 5 to 50 mole alkylene oxide adducts of castor oil, and mixtures of these.

Examples of polyvalent carboxylic acids used in the preparation of polyester polyols (2) to (4) include aliphatic dicarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, maleic anhydride, fumaric acid, 1,3-cyclopentanedicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid; aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalic acid, biphenyldicarboxylic acid, and 1,2-bis(phenoxy)ethane-p,p'-dicarboxylic acid; and anhydrides or ester-forming derivatives of these aliphatic or dicarboxylic acids; polybasic acids such as p-hydroxybenzoic acid, p-(2-hydroxyethoxy)benzoic acid, and ester-forming derivatives of these dihydroxycarboxylic acids, and dimer acid.

The polyol preferably contains at least one of a polyether polyol or a polyester polyol.

The number average molecular weight of the polyol is not particularly limited, but is preferably 300 to 4000. The number average molecular weight in this specification is a value measured by gel permeation chromatography (GPC) under the following conditions.

Measuring device: Tosoh Corporation HLC-8320GPC
Column: TSKgel 4000HXL, TSKgel 3000HXL, TSKgel 2000HXL, TSKgel 1000HXL manufactured by Tosoh Corporation
Detector: RI (differential refractometer)
Data processing: Multistation GPC-8020 model II manufactured by Tosoh Corporation
Measurement conditions: Column temperature: 40°C
Solvent Tetrahydrofuran
Flow rate: 0.35 ml/min. Standard: Monodisperse polystyrene Sample: 100 μl of a tetrahydrofuran solution containing 0.2% by mass of resin solids filtered through a microfilter

The polyisocyanate composition contains a polyisocyanate compound having multiple isocyanate groups. As the polyisocyanate compound, any conventionally known compound can be used without particular limitation, and examples thereof include aromatic diisocyanates, araliphatic diisocyanates, aliphatic diisocyanates, alicyclic diisocyanates, and biuret, nurate, adduct, allophanate, carbodiimide-modified, uretdione-modified, and urethane prepolymers obtained by reacting these polyisocyanates with polyols, and these compounds can be used alone or in combination.

Examples of aromatic diisocyanates include, but are not limited to, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate (also called polymeric MDI or crude MDI), 1,3-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-toluidine diisocyanate, 2,4,6-triisocyanate toluene, 1,3,5-triisocyanate benzene, dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate, and 4,4',4"-triphenylmethane triisocyanate.

Aromatic aliphatic diisocyanates refer to aliphatic isocyanates having one or more aromatic rings in the molecule, and examples include, but are not limited to, m- or p-xylylene diisocyanate (also known as XDI), α,α,α',α'-tetramethylxylylene diisocyanate (also known as TMXDI), etc.

Examples of aliphatic diisocyanates include, but are not limited to, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (also known as HDI), pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate.

Examples of alicyclic diisocyanates include, but are not limited to, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, isophorone diisocyanate (also known as IPDI), 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), 1,4-bis(isocyanatomethyl)cyclohexane, and the like.

The polyol used in the synthesis of the urethane prepolymer may be the same as those exemplified above. It is preferable to use at least one of polyalkylene glycol or polyester polyol.

For flexible packaging substrates, polyisocyanates obtained by reacting aromatic polyisocyanates with polyalkylene glycols having a number average molecular weight in the range of 200 to 6,000, and polyisocyanates obtained by reacting aromatic polyisocyanates with polyester polyols having a number average molecular weight in the range of 200 to 3,000 are preferred because they can impart appropriate flexibility to the cured product. Polyisocyanates with an isocyanate content of 5 to 20% by mass as determined by titration method (using di-n-butylamine) are preferred because they provide appropriate resin viscosity and excellent coatability.

On the other hand, for hard substrates, polyisocyanates obtained by reacting an aromatic polyisocyanate with a polyester polyol having a number average molecular weight in the range of 200 to 3,000, and polyisocyanates obtained by reacting an aromatic polyisocyanate with a mixture of a polyester polyol having a number average molecular weight in the range of 200 to 3,000 and a polyalkylene glycol having a number average molecular weight in the range of 200 to 6,000 are preferred because they have excellent adhesive strength. Those with an isocyanate content of 5 to 20% by mass according to the standard method (using di-n-butylamine) are also preferred because they have an appropriate resin viscosity and excellent coatability.

When the polyisocyanate compound is a urethane prepolymer, it is preferable that the polyisocyanate and polyol used in the synthesis reaction have an equivalent ratio [NCO]/[OH] of isocyanate groups to hydroxyl groups in the range of 1.5 to 5.0, as this brings the viscosity of the adhesive into an appropriate range and provides good coatability.

The adhesive may contain components other than those mentioned above. The other components may be contained in either or both of the polyol composition and the polyisocyanate composition, or may be prepared separately from these and mixed with the polyol composition and the polyisocyanate composition immediately before application of the adhesive. Each component is described below.

The adhesive used in the present invention may contain a catalyst. Examples of catalysts include metal catalysts, amine catalysts, and aliphatic cyclic amide compounds.

Examples of metal catalysts include metal complex catalysts, inorganic metal catalysts, and organic metal catalysts. Examples of metal complex catalysts include acetylacetonate salts of metals selected from the group consisting of Fe (iron), Mn (manganese), Cu (copper), Zr (zirconium), Th (thorium), Ti (titanium), Al (aluminum), and Co (cobalt), such as iron acetylacetonate, manganese acetylacetonate, copper acetylacetonate, and zirconia acetylacetonate.

Examples of inorganic metal catalysts include those selected from Sn, Fe, Mn, Cu, Zr, Th, Ti, Al, Co, etc.

Examples of organometallic catalysts include organozinc compounds such as zinc octylate, zinc neodecanoate, and zinc naphthenate; organotin compounds such as stannous diacetate, stannous dioctoate, stannous dioleate, stannous dilaurate, dibutyltin diacetate, dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin oxide, and dibutyltin dichloride; organonickel compounds such as nickel octylate and nickel naphthenate; organocobalt compounds such as cobalt octylate and cobalt naphthenate; organobismuth compounds such as bismuth octylate, bismuth neodecanoate, and bismuth naphthenate; and titanium compounds such as tetraisopropyloxytitanate, dibutyltitanium dichloride, tetrabutyltitanium, butoxytitanium trichloride, aliphatic diketones, aromatic diketones, and titanium chelate complexes having at least one of the following alcohols having 2 to 10 carbon atoms as a ligand.

Examples of amine catalysts include triethylenediamine, 2-methyltriethylenediamine, quinuclidine, 2-methylquinuclidine, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetramethylpropylenediamine, N,N,N',N",N"-pentamethyldiethylenetriamine, N,N,N',N",N"-pentamethyl-(3-aminopropyl)ethylenediamine, N,N,N',N",N"-pentamethyldipropylenetriamine, N,N,N',N'-tetramethylhexamethylenediamine, bis(2-dimethylaminoethyl)ether, dimethylethanolamine, dimethylisopropanolamine, dimethylaminoethoxyethanol, N,N-dimethyl-N'-(2-hydroxyethyl)ethylenediamine, N,N-dimethyl-N'-(2-hydroxyethyl)propanediamine, bis(dimethylaminopropyl)amine, bis(dimethylaminopropyl)isopropanediamine, propanolamine, 3-quinuclidinol, N,N,N',N'-tetramethylguanidine, 1,3,5-tris(N,N-dimethylaminopropyl)hexahydro-S-triazine, 1,8-diazabicyclo[5.4.0]undecene-7, N-methyl-N'-(2-dimethylaminoethyl)piperazine, N,N'-dimethylpiperazine, dimethylcyclohexylamine, N-methylmorpholine, N-ethylmorpholine, 1-methylimidazole, 1 , 2-dimethylimidazole, 1-isobutyl-2-methylimidazole, 1-dimethylaminopropylimidazole, N,N-dimethylhexanolamine, N-methyl-N'-(2-hydroxyethyl)piperazine, 1-(2-hydroxyethyl)imidazole, 1-(2-hydroxypropyl)imidazole, 1-(2-hydroxyethyl)-2-methylimidazole, 1-(2-hydroxypropyl)-2-methylimidazole, and the like.

Aliphatic cyclic amide compounds include δ-valerolactam, ε-caprolactam, ω-enantholactam, η-capryllactam, β-propiolactam, etc. Among these, ε-caprolactam is more effective in promoting hardening.

The adhesive used in the present invention may contain an acid anhydride. Examples of the acid anhydride include cyclic aliphatic acid anhydrides, aromatic acid anhydrides, unsaturated carboxylic acid anhydrides, etc., and one or more of them may be used in combination. More specifically, for example, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic acid anhydride, dodecenyl succinic anhydride, polyadipic anhydride, polyazelaic anhydride, polysebacic anhydride, poly(ethyl octadecanedioic acid) anhydride, poly(phenyl hexadecanedioic acid) anhydride, tetrahydrophthalic anhydride, methyl tetrahydrophthalic anhydride, methyl hexahydrophthalic anhydride, hexahydrophthalic anhydride, methyl hymic anhydride, trialkyl tetrahydrophthalic anhydride, Examples of the anhydride include methylcyclohexene dicarboxylic anhydride, methylcyclohexene tetracarboxylic anhydride, ethylene glycol bistrimellitate dianhydride, HET anhydride, Nadic anhydride, methylnadic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexane-1,2-dicarboxylic anhydride, 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic dianhydride, and 1-methyl-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic dianhydride.

The above-mentioned compounds may be modified with glycol as the acid anhydride. Examples of glycols that can be used for modification include alkylene glycols such as ethylene glycol, propylene glycol, and neopentyl glycol; and polyether glycols such as polyethylene glycol, polypropylene glycol, and polytetramethylene ether glycol. Furthermore, copolymer polyether glycols of two or more of these glycols and/or polyether glycols may be used.

The adhesive used in the present invention may contain a coupling agent. Examples of the coupling agent include a silane coupling agent, a titanate coupling agent, and an aluminum coupling agent.

Examples of silane coupling agents include aminosilanes such as γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-β(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β(aminoethyl)-γ-aminopropyltrimethyldimethoxysilane, and N-phenyl-γ-aminopropyltrimethoxysilane; epoxysilanes such as β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-glycidoxypropyltriethoxysilane; vinylsilanes such as vinyltris(β-methoxyethoxy)silane, vinyltriethoxysilane, vinyltrimethoxysilane, and γ-methacryloxypropyltrimethoxysilane; hexamethyldisilazane, γ-mercaptopropyltrimethoxysilane, and the like.

Examples of titanate coupling agents include tetraisopropoxytitanium, tetra-n-butoxytitanium, butyl titanate dimer, tetrastearyl titanate, titanium acetylacetonate, titanium lactate, tetraoctylene glycol titanate, titanium lactate, tetrastearoxytitanium, etc.

Examples of aluminum-based coupling agents include acetoalkoxyaluminum diisopropylate.

The adhesive used in the present invention may contain a pigment. There are no particular limitations on the pigment, and examples include organic pigments such as extender pigments, white pigments, black pigments, gray pigments, red pigments, brown pigments, green pigments, blue pigments, metal powder pigments, luminescent pigments, and pearlescent pigments, as well as inorganic pigments and plastic pigments, as described in the Paint Raw Materials Handbook 1970 Edition (edited by the Japan Paint Manufacturers Association).

Examples of extender pigments include precipitated barium sulfate, powdered gourd, precipitated calcium carbonate, calcium bicarbonate, kansui stone, alumina white, silica, hydrous fine silica (white carbon), ultrafine anhydrous silica (aerosil), silica sand, talc, precipitated magnesium carbonate, bentonite, clay, kaolin, and yellow earth.

Specific examples of organic pigments include various insoluble azo pigments such as Benzidine Yellow, Hansa Yellow, Lake 4R, etc.; soluble azo pigments such as Lake C, Carmine 6B, Bordeaux 10, etc.; various (copper) phthalocyanine pigments such as Phthalocyanine Blue and Phthalocyanine Green; various chlorine dyeing lakes such as Rhodamine Lake and Methyl Violet Lake; various mordant dye pigments such as Quinoline Lake and Fast Sky Blue; various vat dye pigments such as Anthraquinone pigments, Thioindigo pigments, Perinone pigments; various quinacridone pigments such as Synchasia Red B; various dioxazine pigments such as Dioxazine Violet; various condensed azo pigments such as Chromophtal; aniline black, etc.

Inorganic pigments include various chromates such as yellow lead, zinc chromate, molybdate orange, etc.; various ferrocyanide compounds such as Prussian blue; various metal oxides such as titanium oxide, zinc oxide, mapico yellow, iron oxide, red iron oxide, chrome oxide green, zirconium oxide, etc.; various sulfides or selenides such as cadmium yellow, cadmium red, mercury sulfide, etc.; various sulfates such as barium sulfate, lead sulfate, etc.; various silicates such as calcium silicate and ultramarine blue; various carbonates such as calcium carbonate and magnesium carbonate; various phosphates such as cobalt violet and manganese purple; various metal powder pigments such as aluminum powder, gold powder, silver powder, copper powder, bronze powder, brass powder, etc.; flake pigments of these metals, mica flake pigments; metallic pigments and pearl pigments such as mica flake pigments coated with metal oxides and micaceous iron oxide pigments; graphite, carbon black, etc.

Examples of plastic pigments include "Grandol PP-1000" and "PP-2000S" manufactured by DIC Corporation.

The pigments used may be selected appropriately depending on the purpose. For example, inorganic oxides such as titanium oxide and zinc oxide are preferred as white pigments, as they have excellent durability, weather resistance, and design properties, while carbon black is preferred as a black pigment.

The adhesive used in the present invention may contain a plasticizer. Examples of the plasticizer include phthalic acid plasticizers, fatty acid plasticizers, aromatic polycarboxylic acid plasticizers, phosphoric acid plasticizers, polyol plasticizers, epoxy plasticizers, polyester plasticizers, and carbonate plasticizers.

Examples of phthalic acid plasticizers include phthalic acid ester plasticizers such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diisobutyl phthalate, dihexyl phthalate, diheptyl phthalate, di-(2-ethylhexyl) phthalate, di-n-octyl phthalate, dinonyl phthalate, diisononyl phthalate, didecyl phthalate, diisodecyl phthalate, ditridecyl phthalate, diundecyl phthalate, dilauryl phthalate, distearyl phthalate, diphenyl phthalate, dibenzyl phthalate, butyl benzyl phthalate, dicyclohexyl phthalate, octyl decyl phthalate, dimethyl isophthalate, di-(2-ethylhexyl) isophthalate, and diisooctyl isophthalate; and tetrahydrophthalic acid ester plasticizers such as di-(2-ethylhexyl) tetrahydrophthalate, di-n-octyl tetrahydrophthalate, and diisodecyl tetrahydrophthalate.

Examples of fatty acid plasticizers include adipic acid plasticizers such as di-n-butyl adipate, di-(2-ethylhexyl) adipate, diisodecyl adipate, diisononyl adipate, di(C6-C10 alkyl) adipate, and dibutyl diglycol adipate; azelaic acid plasticizers such as di-n-hexyl azelate, di-(2-ethylhexyl) azelate, and diisooctyl azelate; and di-n-butyl sebacate, di-(2 sebacic acid plasticizers such as di-(2-ethylhexyl) sebacate and diisononyl sebacate; maleic acid plasticizers such as dimethyl maleate, diethyl maleate, di-n-butyl maleate and di-(2-ethylhexyl) maleate; fumaric acid plasticizers such as di-n-butyl fumarate and di-(2-ethylhexyl) fumarate; monomethyl itaconate, monobutyl itaconate, dimethyl itaconate, diethyl itaconate, dibutyl itaconate, Examples of the plasticizer include itaconic acid-based plasticizers such as luitaconate and di-(2-ethylhexyl) itaconate; stearic acid-based plasticizers such as n-butyl stearate, glycerin monostearate, and diethylene glycol distearate; oleic acid-based plasticizers such as butyl oleate, glyceryl monooleate, and diethylene glycol monooleate; citric acid-based plasticizers such as triethyl citrate, tri-n-butyl citrate, acetyl triethyl citrate, acetyl tributyl citrate, and acetyl tri-(2-ethylhexyl) citrate; ricinoleic acid-based plasticizers such as methyl acetyl ricinoleate, butyl acetyl ricinoleate, glyceryl monoricinoleate, and diethylene glycol monoricinoleate; and other fatty acid-based plasticizers such as diethylene glycol monolaurate, diethylene glycol dipelargonate, and pentaerythritol fatty acid esters.

Examples of aromatic polycarboxylic acid plasticizers include trimellitic acid plasticizers such as tri-n-hexyl trimellitate, tri-(2-ethylhexyl) trimellitate, tri-n-octyl trimellitate, triisooctyl trimellitate, triisononyl trimellitate, tridecyl trimellitate, and triisodecyl trimellitate; and pyromellitic acid plasticizers such as tetra-(2-ethylhexyl) pyromellitate and tetra-n-octyl pyromellitate.

Examples of phosphate plasticizers include triethyl phosphate, tributyl phosphate, tri-(2-ethylhexyl) phosphate, tributoxyethyl phosphate, triphenyl phosphate, octyl diphenyl phosphate, cresyl diphenyl phosphate, cresyl phenyl phosphate, tricresyl phosphate, trixylenyl phosphate, tris(chloroethyl) phosphate, tris(chloropropyl) phosphate, tris(dichloropropyl) phosphate, and tris(isopropylphenyl) phosphate.

Examples of polyol-based plasticizers include glycol-based plasticizers such as diethylene glycol dibenzoate, dipropylene glycol dibenzoate, triethylene glycol dibenzoate, triethylene glycol di-(2-ethylbutyrate), triethylene glycol di-(2-ethylhexoate), and dibutylmethylene bisthioglycolate; and glycerin-based plasticizers such as glycerol monoacetate, glycerol triacetate, and glycerol tributyrate.

Examples of epoxy plasticizers include epoxidized soybean oil, epoxy butyl stearate, di-2-ethylhexyl epoxy hexahydrophthalate, diisodecyl epoxy hexahydrophthalate, epoxy triglyceride, epoxidized octyl oleate, and epoxidized decyl oleate.

Examples of polyester plasticizers include adipic acid polyesters, sebacic acid polyesters, and phthalic acid polyesters.

Examples of carbonate-based plasticizers include propylene carbonate and ethylene carbonate.

Other examples of plasticizers include partially hydrogenated terphenyls, adhesive plasticizers, and polymerizable plasticizers such as diallyl phthalate, acrylic monomers and oligomers. These plasticizers can be used alone or in combination of two or more.

The adhesive used in the present invention may contain a phosphoric acid compound. Examples of phosphoric acid compounds include phosphoric acid, pyrophosphoric acid, triphosphoric acid, methyl acid phosphate, ethyl acid phosphate, butyl acid phosphate, dibutyl phosphate, 2-ethylhexyl acid phosphate, bis(2-ethylhexyl) phosphate, isododecyl acid phosphate, butoxyethyl acid phosphate, oleyl acid phosphate, tetracosyl acid phosphate, 2-hydroxyethyl methacrylate acid phosphate, polyoxyethylene alkyl ether phosphate, and the like.

The adhesive used in the present invention may be either a solvent-based or solventless type. In this specification, a "solvent-based" adhesive refers to a type used in a method in which the adhesive is applied to a substrate, heated in an oven or the like to volatilize the organic solvent in the coating, and then laminated to another substrate, the so-called dry lamination method. Either the polyol composition or the polyisocyanate composition, or both, contain an organic solvent capable of dissolving (diluting) the components of the polyol composition and the polyisocyanate composition.

Examples of organic solvents include esters such as ethyl acetate, butyl acetate, cellosolve acetate, etc., ketones such as acetone, methyl ethyl ketone, isobutyl ketone, cyclohexanone, etc., ethers such as tetrahydrofuran, dioxane, etc., aromatic hydrocarbons such as toluene, xylene, etc., halogenated hydrocarbons such as methylene chloride, ethylene chloride, etc., dimethyl sulfoxide, dimethyl sulfamide, etc. The organic solvent used as a reaction medium during the production of the components of the polyol composition and polyisocyanate composition may also be used as a diluent during coating.

In this specification, the term "solvent-free" adhesive refers to an adhesive form used in a method in which the polyol composition and polyisocyanate composition are substantially free of the highly soluble organic solvents exemplified above, particularly ethyl acetate or methyl ethyl ketone, and the adhesive is applied to a substrate and then laminated to another substrate without undergoing a process of volatilizing the solvent by heating in an oven or the like, which is known as a non-solvent lamination method. If the organic solvent used as a reaction medium in the components of the polyol composition and polyisocyanate composition or in the production of the raw materials for the polyol composition and polyisocyanate composition cannot be completely removed and a trace amount of organic solvent remains in the polyol composition and polyisocyanate composition, it is understood that the polyol composition is substantially free of organic solvent. In addition, if the polyol composition contains a low molecular weight alcohol, the low molecular weight alcohol reacts with the polyisocyanate composition to become part of the coating film, so there is no need to volatilize it after application. Therefore, such a form is also treated as a solvent-free adhesive, and the low molecular weight alcohol is not considered to be an organic solvent.

It is preferable to use the adhesive by blending it so that the ratio [NCO]/[OH] of the number of moles of isocyanate groups contained in the polyisocyanate composition [NCO] to the number of moles of hydroxyl groups contained in the polyol composition [OH] is 1.0 to 3.0. This makes it possible to obtain appropriate curing properties without depending on the environmental humidity at the time of coating.

The thickness of the adhesive layer can be adjusted as appropriate, but an example is 0.5 μm or more and 6 μm or less.

(Deposition layer)
The heat seal layer may further have a vapor deposition layer on the surface on the stretched polyolefin film side. Examples of the vapor deposition layer include vapor deposition layers containing metals such as aluminum, and inorganic oxides such as aluminum oxide, silicon oxide, magnesium oxide, calcium oxide, zirconium oxide, titanium oxide, boron oxide, hafnium oxide, and barium oxide. From the viewpoints of oxygen barrier property and water vapor barrier property, an aluminum vapor deposition layer is preferred.

The stretched polyolefin film may also have a vapor-deposited layer containing an inorganic oxide such as aluminum oxide, silicon oxide, magnesium oxide, calcium oxide, zirconium oxide, titanium oxide, boron oxide, hafnium oxide, or barium oxide on the surface facing the heat seal layer.

The deposition layer can be formed by a conventional method, for example, physical vapor deposition methods (PVD method) such as vacuum deposition, sputtering, and ion plating, chemical vapor deposition methods (CVD method) such as plasma chemical vapor deposition, thermal chemical vapor deposition, and photochemical vapor deposition.

In the case of an aluminum vapor deposition film, the thickness of the vapor deposition film is preferably 1 nm to 100 nm, more preferably 15 nm to 60 nm, and even more preferably 10 nm to 40 nm. In the case of a silicon oxide or aluminum oxide vapor deposition film, the thickness is preferably 1 nm to 140 nm, more preferably 5 nm to 30 nm, and even more preferably 5 nm to 20 nm.

Also, for example, a composite film consisting of two or more layers of vapor-deposited films of different inorganic oxides can be formed and used by combining both physical vapor deposition and chemical vapor deposition. The degree of vacuum in the vapor deposition chamber is preferably about 10 ^-2 to 10 ^-8 mbar before oxygen is introduced, and is preferably about 10 ^-1 to 10 ^-6 mbar after oxygen is introduced. The amount of oxygen introduced varies depending on the size of the vapor deposition machine. For the oxygen to be introduced, an inert gas such as argon gas, helium gas, or nitrogen gas may be used as a carrier gas to the extent that no problems occur. The film transport speed is preferably about 10 to 800 m/min, particularly about 50 to 600 m/min.

(Barrier Coat Layer)
The laminate of the present invention may have a barrier coat layer at any position on the heat seal layer side of the above-mentioned coat layer. In particular, when the laminate of the present invention has a deposition layer, it is preferable to provide the barrier coat layer on the deposition layer. This can prevent cracks from occurring in the deposition layer, and the laminate of the present invention can have excellent gas barrier properties.

The barrier coat layer can be formed by a conventionally known method using a conventionally known composition. One example is a film made of a gas barrier composition such as an alkoxide hydrolysate or an alkoxide hydrolysis condensate obtained by polycondensing an alkoxide and a water-soluble polymer by the sol-gel method in the presence of a sol-gel catalyst, acid, water, and an organic solvent. It may further contain a silane coupling agent.

As the alkoxide, at least one alkoxide represented by the general formula R ¹ _n M(OR ² ) _m can be used. In the above formula, R ¹ and R ² represent an organic group having 1 to 8 carbon atoms, M represents a metal atom, n represents an integer of 0 or more, m represents an integer of 1 or more, and n+m represents the atomic valence of M. As the metal atom M, silicon, zirconium, titanium, aluminum, etc. can be used. Specific examples of the organic group represented by ^{R 1} and R ² include alkyl groups such as methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, and i-butyl group. These alkyl groups may be the same or different in the same molecule. Specific examples of the alkoxide include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane.

As the water-soluble polymer, either or both of polyvinyl alcohol resins and ethylene-vinyl alcohol copolymers can be preferably used. These resins may be commercially available. For example, as the ethylene-vinyl alcohol copolymer, EVAL EP-F101 (ethylene content: 32 mol%) manufactured by Kuraray Co., Ltd., and Soarnol D2908 (ethylene content: 29 mol%) manufactured by Nippon Synthetic Chemical Industry Co., Ltd. can be used. As the polyvinyl alcohol, RS-110 (saponification degree = 99%, polymerization degree = 1,000) manufactured by Kuraray Co., Ltd., Kuraray Poval LM-20SO (saponification degree = 40%, polymerization degree = 2,000), and Gohsenol NM-14 (saponification degree = 99%, polymerization degree = 1,400) manufactured by Nippon Synthetic Chemical Industry Co., Ltd. can be used.
The content of the water-soluble polymer is, for example, 5 to 500 parts by mass per 100 parts by mass of the alkoxide.

As the sol-gel catalyst, a tertiary amine is used. For example, N,N-dimethylbenzylamine, tripropylamine, tributylamine, tripentylamine, etc. can be used. N,N-dimethylbenzylamine is particularly preferred. It is preferable to use, for example, 0.01 to 1.0 part by mass per 100 parts by mass of the total amount of alkoxysilane and silane coupling agent.

Organic solvents that can be used include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butanol, etc.

Examples of silane coupling agents include gamma-glycidoxypropyltrimethoxysilane, gamma-glycidoxypropylmethyldiethoxysilane, (3-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, etc., and one or more of them can be used in combination. The amount of silane coupling agent used is 1 to 20 parts by mass per 100 parts by mass of alkoxide.

The barrier coat layer is formed by applying once or a plurality of times by a conventionally known method such as roll coating using a gravure roll coater or the like, spray coating, spin coating, dipping, brush coating, bar coating, or applicator.
The thickness of the barrier coat layer is appropriately adjusted, but is, for example, about 0.01 to 100 μm, and more preferably 0.01 to 50 μm.

(Printing layer)
The laminate of the present invention may have a printed layer. The printed layer is a layer on which characters, figures, symbols, and other desired patterns are printed using liquid ink. The printed layer may be provided at any position, and examples include between the stretched polyolefin substrate and the adhesive layer (between a deposition layer or a gas barrier coating layer and the adhesive layer when such a layer is provided), or between the stretched polyolefin substrate and the coating layer. In this specification, liquid ink is a general term for solvent-based inks used in gravure printing or flexographic printing. The liquid ink may contain resin, colorant, and solvent as essential components, or may be a so-called clear ink that contains resin and solvent and substantially does not contain colorant.

The resin used in the liquid ink is not particularly limited, and examples thereof include acrylic resin, polyester resin, styrene resin, styrene-maleic acid resin, maleic acid resin, polyamide resin, polyurethane resin, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-acrylic copolymer resin, ethylene-vinyl acetate copolymer resin, vinyl acetate resin, polyvinyl chloride resin, chlorinated polypropylene resin, cellulose-based resin, epoxy resin, alkyd resin, rosin-based resin, rosin-modified maleic acid resin, ketone resin, cyclized rubber, chlorinated rubber, butyral, petroleum resin, etc., and one or more types can be used in combination. Preferably, at least one type, or two or more types selected from polyurethane resin, vinyl chloride-vinyl acetate copolymer resin, and cellulose-based resin are used.

Colorants used in liquid inks include inorganic pigments such as titanium oxide, red iron oxide, antimony red, cadmium red, cadmium yellow, cobalt blue, Prussian blue, ultramarine, carbon black, and graphite; organic pigments such as soluble azo pigments, insoluble azo pigments, azo lake pigments, condensed azo pigments, copper phthalocyanine pigments, and condensed polycyclic pigments; and extender pigments such as calcium carbonate, kaolin clay, barium sulfate, aluminum hydroxide, and talc.

It is preferable that the organic solvent used in the liquid ink does not contain an aromatic hydrocarbon-based organic solvent. More specifically, examples of the organic solvent include alcohol-based organic solvents such as methanol, ethanol, n-propanol, isopropanol, and butanol; ketone-based organic solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; ester-based organic solvents such as methyl acetate, ethyl acetate, propyl acetate, and butyl acetate; aliphatic hydrocarbon-based organic solvents such as n-hexane, n-heptane, and n-octane; and alicyclic hydrocarbon-based organic solvents such as cyclohexane, methylcyclohexane, ethylcyclohexane, cycloheptane, and cyclooctane. These organic solvents can be used alone or in combination of two or more.

(Primer layer)
The laminate of the present invention may further include a primer layer between the stretched polyolefin film and the coating layer in order to improve the adhesion of the coating layer.

The heat resistance of the laminate of the present invention can be improved by disposing the above-mentioned coating layer at the position where it comes into contact with the heat seal bar. In other words, the thermal shrinkage of the laminate during heat sealing can be suppressed, and heat sealing can be performed at a temperature about 20°C higher than for a laminate without a coating layer.

Furthermore, the above-mentioned coating layer can be easily peeled off from the stretched polyolefin film by subjecting the laminate of the present invention to an alkali treatment. This method also makes it possible to peel off or dissolve the adhesive layer, printing layer, deposition layer, etc. from the substrate (stretched polyolefin or heat seal layer). From this point of view, the laminate of the present invention has excellent recyclability.

As the alkaline solution used to peel off the coating layer, an aqueous solution of sodium hydroxide or an aqueous solution of potassium hydroxide is preferred. The aqueous solution of sodium hydroxide or potassium hydroxide has a concentration of preferably 0.5% to 10% by mass, and more preferably 1% to 5% by mass. The pH is preferably 10 or higher.

The alkaline solution may contain a water-soluble organic solvent. Examples of water-soluble organic solvents include methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, ethylene glycol monomethyl ether (methyl cellosolve), ethylene glycol monoethyl ether (cellosolve), ethylene glycol monobutyl ether (butyl cellosolve), ethylene glycol dibutyl ether, diethylene glycol monomethyl ether (methyl carbitol), diethylene glycol dimethyl ether, diethylene glycol monoethyl ether (carbitol), diethylene glycol diethyl ether (diethyl carbitol), diethylene glycol monobutyl ether (butyl carbitol), diethylene glycol dibutyl ether, and triethylene glycol. Examples include cholesteryl monomethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, methylene dimethyl ether (methylal), propylene glycol monobutyl ether, tetrahydrofuran, acetone, diacetone alcohol, acetonylacetone, acetylacetone, ethylene glycol monomethyl ether acetate (methyl cellosolve acetate), diethylene glycol monomethyl ether acetate (methyl carbitol acetate), diethylene glycol monoethyl ether acetate (carbitol acetate), ethyl hydroxyisobutyrate, and ethyl lactate, which may be used alone or in combination of two or more.

The content of the water-soluble organic solvent in the alkaline solution is preferably 0.1% by mass to 20% by mass, and more preferably 1% by mass to 10% by mass.

The alkaline solution may also contain a water-insoluble organic solvent. Specific examples of water-insoluble organic solvents include alcohol-based solvents such as n-butanol, 2-butanol, isobutanol, and octanol; aliphatic hydrocarbon-based solvents such as hexane, heptane, and normal paraffin; aromatic hydrocarbon-based solvents such as benzene, toluene, xylene, and alkylbenzene; halogenated hydrocarbon-based solvents such as methylene chloride, 1-chlorobutane, 2-chlorobutane, 3-chlorobutane, and carbon tetrachloride; ester-based solvents such as methyl acetate, ethyl acetate, and butyl acetate; ketone-based solvents such as methyl isobutyl ketone, methyl ethyl ketone, and cyclohexanone; and ether-based solvents such as ethyl ether and butyl ether. These may be used alone or in combination of two or more.

The alkaline solution may contain a surfactant. Examples of the surfactant include various anionic surfactants, nonionic surfactants, cationic surfactants, and amphoteric surfactants. Among these, anionic surfactants and nonionic surfactants are preferred.

Examples of anionic surfactants include alkylbenzenesulfonates, alkylphenylsulfonates, alkylnaphthalenesulfonates, higher fatty acid salts, sulfate ester salts of higher fatty acid esters, sulfonates of higher fatty acid esters, sulfate ester salts and sulfonates of higher alcohol ethers, higher alkyl sulfosuccinates, polyoxyethylene alkyl ether carboxylates, polyoxyethylene alkyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, and the like. Specific examples of these include dodecylbenzenesulfonate, isopropylnaphthalenesulfonate, monobutylphenylphenol monosulfonate, monobutylbiphenylsulfonate, and dibutylphenylphenol disulfonate.

Examples of nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, glycerin fatty acid esters, polyoxyethylene glycerin fatty acid esters, polyglycerin fatty acid esters, sucrose fatty acid esters, polyoxyethylene alkylamines, polyoxyethylene fatty acid amides, fatty acid alkylol amides, alkyl alkanol amides, acetylene glycol, oxyethylene adducts of acetylene glycol, polyethylene glycol polypropylene glycol block copolymers, etc. Polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene dodecylphenyl ether, polyoxyethylene alkyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, fatty acid alkylol amides, acetylene glycol, oxyethylene adducts of acetylene glycol, and polyethylene glycol polypropylene glycol block copolymers are preferred.

Other surfactants that can be used include silicone-based surfactants such as polysiloxane oxyethylene adducts; fluorine-based surfactants such as perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, and oxyethylene perfluoroalkyl ethers; and biosurfactants such as spiculisporic acid, rhamnolipids, and lysolecithin.

These surfactants can be used alone or in combination of two or more. When a surfactant is added, the amount added is preferably in the range of 0.001 to 2% by mass, more preferably 0.001 to 1.5% by mass, and even more preferably 0.01 to 1% by mass, based on the total amount of the alkaline solution.

Methods for peeling the coating layer from the laminate of the present invention include immersing the laminate of the present invention in the above-mentioned alkaline solution while it is heated to 20 to 90°C or while it is ultrasonically vibrated. There are no particular limitations on the heating method, and known heating methods using heat rays, infrared rays, microwaves, etc. can be used. In addition, ultrasonic vibration can be, for example, a method in which an ultrasonic vibrator is attached to a treatment tank and ultrasonic vibration is applied to the alkaline solution.

During immersion, the alkaline solution is preferably stirred. Examples of stirring methods include mechanically stirring the dispersion of the laminated film contained in the treatment tank with a stirring blade, water flow stirring with a water flow pump, and bubbling with an inert gas such as nitrogen gas. The above-mentioned methods may be used in combination to efficiently peel off the multilayer film.

The time for which the laminate is immersed in the alkaline solution depends on the composition of the laminate, but ranges from 2 minutes to 48 hours, for example.

<Packaging materials>
The laminate of the present invention can be used as a multi-layer packaging material for protecting foods, medicines, etc. When used as a multi-layer packaging material, the layer structure can be changed depending on the contents, the environment of use, and the form of use.

The packaging material of the present invention can be obtained, for example, by overlapping the heat seal layers of the laminate of the present invention so that they face each other, and then heat sealing the peripheral edges. Examples of bag-making methods include folding or overlapping the laminate of the present invention so that the surfaces of the inner layers (the surfaces of the sealant film) face each other, and heat sealing the peripheral edges, for example, by using a side seal type, a two-sided seal type, a three-sided seal type, a four-sided seal type, an envelope seal type, a grooving seal type, a pleated seal type, a flat bottom seal type, a square bottom seal type, a gusset type, or other heat seal type. The packaging material of the present invention can take various forms depending on the contents, the environment in which it is used, and the form of use. Self-supporting packaging materials (standing pouches) are also possible. Heat sealing can be performed by known methods such as bar seal, rotary roll seal, belt seal, impulse seal, high frequency seal, and ultrasonic seal.

The packaging material of the present invention is filled with the contents through its opening, and the opening is then heat-sealed to produce a product using the packaging material of the present invention. The contents to be filled include confectioneries such as rice crackers, bean snacks, nuts, biscuits and cookies, wafer snacks, marshmallows, pies, semi-dried cakes, candies, and snack foods; staple foods such as bread, snack noodles, instant noodles, dried noodles, pasta, aseptically packaged cooked rice, porridge, porridge, packaged rice cakes, and cereal foods; agricultural processed products such as pickles, boiled beans, natto, miso, frozen tofu, tofu, nametake mushrooms, konjac, wild vegetable processed products, jams, peanut cream, salads, frozen vegetables, and potato processed products; livestock processed products such as hams, bacon, sausages, chicken processed products, and corned beef; and fish ham and sausages. Examples of the food products that can be used include processed fishery products such as fish paste, fish paste products, kamaboko, nori, tsukudani, bonito flakes, shiokara, smoked salmon, and spicy cod roe, fruit pulp such as peaches, mandarin oranges, pineapples, apples, pears, and cherries, vegetables such as corn, asparagus, mushrooms, onions, carrots, radishes, and potatoes, prepared foods such as frozen and chilled prepared foods, typified by hamburger steaks, meatballs, seafood fries, gyoza dumplings, and croquettes, dairy products such as butter, margarine, cheese, cream, instant creamy powder, and infant formula, liquid seasonings, retort curry, and pet food. The packaging material of the present invention can also be used as a packaging material for cigarettes, medicines such as disposable hand warmers and infusion packs, cosmetics, and vacuum insulation materials.

The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited thereto. The compounding composition and other numerical values are based on mass unless otherwise specified.

Details of the compounds used in the examples and comparative examples are as shown in Tables 1 to 4 below.

<Preparation of Composite Resin (A)>
Synthesis Example 1 Preparation of Polysiloxane Segment (a1-1) 415 parts of MTMS and 756 parts of MPTS were charged into a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, a cooling tube, and a nitrogen gas inlet, and the temperature was raised to 60°C while stirring under nitrogen gas aeration. Next, a mixture consisting of 0.1 parts of "A-3" and 121 parts of deionized water was dropped over 5 minutes. After the dropwise addition was completed, the temperature in the reaction vessel was raised to 80°C, and the mixture was stirred for 4 hours to carry out a hydrolysis condensation reaction, and a reaction product was obtained.

The methanol and water contained in the resulting reaction product were removed under reduced pressure of 1 to 30 kilopascals (kPa) at 40 to 60°C to obtain 1,000 parts of polysiloxane segment (a1-1) having a number average molecular weight of 1,000 and an active ingredient content of 75.0%. The "active ingredient" is calculated by dividing the theoretical yield (parts by weight) when all the methoxy groups of the silane monomer used are hydrolyzed and condensed by the actual yield (parts by weight) after the hydrolysis and condensation reaction, that is, by the formula [theoretical yield (parts by weight) when all the methoxy groups of the silane monomer are hydrolyzed and condensed by / actual yield (parts by weight) after the hydrolysis and condensation reaction].

Synthesis Example 2 Preparation of polysiloxane segment (a1-2) 442 parts of MTMS and 760 parts of APTS were charged into a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, a cooling tube, and a nitrogen gas inlet, and the temperature was raised to 60°C while stirring under nitrogen gas aeration. Next, a mixture consisting of 0.1 part of "A-3" and 129 parts of deionized water was dropped over 5 minutes. After the dropwise addition was completed, the temperature in the reaction vessel was raised to 80°C, and the mixture was stirred for 4 hours to carry out a hydrolysis condensation reaction, and a reaction product was obtained.

The methanol and water contained in the obtained reaction product were removed under reduced pressure of 1 to 30 kilopascals (kPa) and at 40 to 60°C to obtain 1,000 parts of polysiloxane segment (a1-2) having a number average molecular weight of 1,000 and an active ingredient content of 75.0%.

Synthesis Example 3 Preparation of Vinyl Polymer Segment (a2-1) 20.1 parts of PTMS, 24.4 parts of DMDMS, and 107.7 parts of n-butyl acetate were charged into a reaction vessel similar to that of Synthesis Example 1, and the mixture was heated to 80° C. while stirring under nitrogen gas aeration. Next, a mixture containing 15 parts of MMA, 45 parts of BMA, 39 parts of EHMA, 1.5 parts of AA, 4.5 parts of MPTS, 45 parts of HEMA, 15 parts of n-butyl acetate, and 15 parts of TBPEH was added dropwise to the reaction vessel over 4 hours at the same temperature while stirring under nitrogen gas aeration. After stirring for another 2 hours at the same temperature, a mixture of 0.05 parts of "A-3" and 12.8 parts of deionized water was added dropwise over 5 minutes to the reaction vessel, and the mixture was stirred for 4 hours at the same temperature to allow the hydrolysis and condensation reaction of PTMS, DMDMS, and MPTS to proceed. When the reaction product was analyzed by 1H-NMR, it was found that almost 100% of the trimethoxysilyl groups of the silane monomer in the reaction vessel had been hydrolyzed. Next, the mixture was stirred for 10 hours at the same temperature to obtain a vinyl polymer segment (a2-1) which was a reaction product having a residual amount of TBPEH of 0.1% or less. The residual amount of TBPEH was measured by iodometric titration.

(Synthesis Example 4) Preparation of vinyl polymer segment (a2-2) 17.6 parts of PTMS, 21.3 parts of DMDMS, and 129 parts of n-butyl acetate were charged into a reaction vessel similar to that of Synthesis Example 1, and the temperature was raised to 80° C. while stirring under nitrogen gas aeration. Next, a mixture containing 21 parts of MMA, 63 parts of BMA, 54.6 parts of EHMA, 2.1 parts of AA, 6.3 parts of MPTS, 63 parts of HEMA, 21 parts of n-butyl acetate, and 21 parts of TBPEH was added dropwise to the reaction vessel over 4 hours at the same temperature while stirring under nitrogen gas aeration. After further stirring at the same temperature for 2 hours, a mixture of 0.04 parts of "A-3" and 11.2 parts of deionized water was added dropwise to the reaction vessel over 5 minutes, and the mixture was stirred at the same temperature for 4 hours to allow the hydrolysis and condensation reaction of PTMS, DMDMS, and MPTS to proceed. The reaction product was analyzed by 1H-NMR, and it was found that almost 100% of the trimethoxysilyl groups of the silane monomer in the reaction vessel had been hydrolyzed. The mixture was then stirred at the same temperature for 10 hours to obtain a vinyl polymer segment (a2-2) as a reaction product containing 0.1% or less of TBPEH remaining.

(Synthesis Example 5) Preparation of vinyl polymer segment (a2-3) 20.1 parts of PTMS, 24.4 parts of DMDMS, and 107.7 parts of n-butyl acetate were charged into a reaction vessel similar to that of Synthesis Example 1, and the mixture was heated to 80°C while stirring under nitrogen gas aeration. Next, a mixture containing 14.5 parts of MMA, 2 parts of BMA, 105 parts of CHMA, 7.5 parts of AA, 4.5 parts of MPTS, 15 parts of HEMA, 15 parts of n-butyl acetate, and 6 parts of TBPEH was added dropwise to the reaction vessel over 4 hours at the same temperature while stirring under nitrogen gas aeration. After further stirring at the same temperature for 2 hours, a mixture of 0.05 parts of "A-3" and 12.8 parts of deionized water was added dropwise to the reaction vessel over 5 minutes, and the mixture was stirred at the same temperature for 4 hours, thereby allowing the hydrolysis and condensation reaction of PTMS, DMDMS, and MPTS to proceed. The reaction product was analyzed by 1H-NMR and found to have undergone hydrolysis of almost 100% of the trimethoxysilyl groups of the silane monomer in the reaction vessel. The mixture was then stirred at the same temperature for 10 hours to obtain a vinyl polymer segment (a2-3) containing 0.1% or less of TBPEH remaining.

(Synthesis Example 6) Preparation of composite resin (A-1) 162.5 parts of polysiloxane (a1-1) obtained in Synthesis Example 1 was added to the total amount of vinyl polymer segment (a2-1) obtained in Synthesis Example 3, and stirred for 5 minutes, and then 27.5 parts of deionized water was added and stirred at 80 ° C. for 4 hours to carry out a hydrolysis condensation reaction of the reaction product and polysiloxane. The reaction product obtained was distilled under reduced pressure of 10 to 300 kPa and at 40 to 60 ° C. for 2 hours to remove the produced methanol and water, and then 150 parts of MEK and 27.3 parts of n-butyl acetate were added to obtain 600 parts of composite resin (A-1) consisting of polysiloxane segment (a1-1) and vinyl polymer segment (a2-1) with a non-volatile content of 50.0%.

(Synthesis Example 7) Preparation of composite resin (A-2) 562.5 parts of the polysiloxane segment (a1-1) obtained in Synthesis Example 1 was added to the total amount of the vinyl polymer segment (a2-1) obtained in Synthesis Example 3, and stirred for 5 minutes. Then, 80 parts of deionized water was added and stirred at 80 ° C. for 4 hours to carry out a hydrolysis condensation reaction of the reaction product and polysiloxane. The reaction product obtained was distilled under reduced pressure of 10 to 300 kPa and at 40 to 60 ° C. for 2 hours to remove the produced methanol and water, and then 128.6 parts of MEK and 5.8 parts of n-butyl acetate were added to obtain 600 parts of composite resin (A-2) consisting of polysiloxane segment (a1-1) and vinyl polymer segment (a2-1) with a non-volatile content of 70.0%.

(Synthesis Example 8) Preparation of composite resin (A-3) 87.3 parts of the polysiloxane segment (a1-1) obtained in Synthesis Example 1 was added to the total amount of the vinyl polymer segment (a2-2) obtained in Synthesis Example 4, and stirred for 5 minutes. Then, 80 parts of deionized water was added and stirred at 80° C. for 4 hours to carry out a hydrolysis condensation reaction of the reaction product and polysiloxane. The reaction product obtained was distilled under reduced pressure of 10 to 300 kPa and at 40 to 60° C. for 2 hours to remove the produced methanol and water, and then 150 parts of MEK was added to obtain 600 parts of composite resin (A-3) consisting of the polysiloxane segment (a1-1) and the vinyl polymer segment (a2-2) with a non-volatile content of 50.0%.

(Synthesis Example 9) Preparation of composite resin (A-4) 162.5 parts of the polysiloxane segment (a1-2) obtained in Synthesis Example 2 was added to the total amount of the vinyl polymer segment (a2-3) obtained in Synthesis Example 5, and stirred for 5 minutes. Then, 27.5 parts of deionized water was added and stirred at 80 ° C. for 4 hours to carry out a hydrolysis condensation reaction of the reaction product and polysiloxane. The reaction product obtained was distilled under reduced pressure of 10 to 300 kPa and at 40 to 60 ° C. for 2 hours to remove the produced methanol and water, and then 150 parts of MEK and 27.3 parts of butyl acetate were added to obtain 600 parts of composite resin (A-4) consisting of polysiloxane segment (a1-2) and vinyl polymer segment (a2-3) with a non-volatile content of 50.0%.

Synthesis Example 10 Preparation of Vinyl Polymer Segment (a2-4) Into a reaction vessel similar to that in Synthesis Example 1, 20.1 parts of PTMS as a silane compound, 24.4 parts of DMDMS, and 107.7 parts of MIBK as a solvent were charged, and the mixture was heated to 95° C. with stirring under nitrogen gas aeration.

Next, a mixture containing 1.5 parts of AA, 1.5 parts of BA, 30.6 parts of MMA, 29.4 parts of BMA, 75 parts of CHMA, 7.5 parts of HEMA, 4.5 parts of MPTS, 6.8 parts of TBPEH, and 15 parts of MIBK was added dropwise to the reaction vessel over 4 hours at the same temperature while stirring under nitrogen gas aeration, and then stirred at the same temperature for 2 hours to obtain a reaction solution containing a vinyl-based polymer having a number average molecular weight of 5800 and a hydroxyl value (OHv) of 64.7 mgKOH/g. A mixture of 0.06 parts of "A-4" and 12.8 parts of deionized water was added dropwise to the reaction vessel over 5 minutes and stirred at the same temperature for 5 hours to allow the hydrolysis and condensation reaction of the silane compound to proceed. The reaction product was analyzed by ^1H -NMR, and it was found that the trimethoxysilyl groups of the silane monomer in the reaction vessel were almost 100% hydrolyzed. The mixture was then stirred at the same temperature for 10 hours to obtain a vinyl polymer segment (a2-4) having a residual amount of TBPEH of 0.1% or less.

(Preparation Example 1) Preparation of Dispersion of Inorganic Particles (m-1) MTMS 651.5 parts, MPTS 1188.2 parts, Aerosil 200 1450.4 parts, "A-4" 0.8 parts, deionized water 258.7 parts, MIBK 1450.4 parts were blended, and dispersion was performed using Ultra Apex Mill UAM015 manufactured by Kotobuki Industries Co., Ltd. In preparing the dispersion, 100 μm zirconia beads were filled as media in the mill at 70% of the mill's volume, and the blend was circulatory-milled at a peripheral speed of 10 m/s and a flow rate of 1.5 liters per minute. Circulatory-milling was performed for 30 minutes to obtain a dispersion of inorganic particles (m-1) in which silica particles were dispersed in the mixture.

(Preparation Example 2) Preparation of Dispersion of Inorganic Particles (m-2) A dispersion of inorganic particles (m-2) was obtained in the same manner as in Preparation Example 1, except that 276.8 parts of MTMS, 504.8 parts of MPTS, 4107.9 parts of IPA-ST, 0.7 parts of “A-4”, and 109.9 parts of deionized water were used, and MIBK was not used.

(Synthesis Example 11) Preparation of composite resin (A-5) 886.3 parts of inorganic particle (m-1) dispersion was added to 336.8 parts of vinyl polymer segment (a2-4), and stirred for 5 minutes, then 14.7 parts of deionized water was added, and stirred at 80 ° C. for 4 hours to carry out hydrolysis condensation reaction between the vinyl polymer segment and the silane compound. The resulting reaction product was distilled under reduced pressure of 1 to 30 kPa and at 40 to 60 ° C. for 2 hours to remove the produced methanol and water, and then 145.1 parts of MIBK and 417.9 parts of DAA were added to obtain a composite resin (A-5) (solid content 35.0%) having a silica content of 33 wt% and bound to inorganic particles (m-1).

(Synthesis Example 12) Preparation of Composite Resin (A-6) [0222] The same procedure as in Synthesis Example 11 was repeated except that 1,217.2 parts of the dispersion of inorganic particles (m-2) was used instead of the dispersion of inorganic particles (m-1), 610.6 parts of MIBK was used, and no DAA was used, to obtain a composite resin (A-6) (solid content 45.2%) having a silica content of 50% by weight and bound to inorganic particles (m-2).

<Preparation of Coating Agent>
Example 1
The coating agent of Example 1 was prepared by adding 50 parts of TMP3EOTA to 100 parts of the composite resin (A-1) (50 parts in terms of solid content).

(Example 2) to (Example 4)
Coating agents of Examples 2 to 4 were prepared in the same manner as in Example 1, except that the composite resin (A), reactive compound, and their blending amounts were changed to those shown in Table 5.

Example 5
A mixture of 50 parts of composite resin (A-1) (25 parts in terms of solid content), 25 parts of silica particles (Aerosil 50 manufactured by Nippon Aerosil Co., Ltd., average primary particle diameter about 30 nm) and 175 parts of MIBK was crushed in circulation for 30 minutes at a flow rate of 1.5 liters per minute using Ultra Apex Mill UAM015 manufactured by Kotobuki Industries Co., Ltd., with 30 μm diameter zirconia beads filled as media in the mill at 50% of the mill's volume. MIBK was removed using an evaporator to obtain 100 parts of a dispersion liquid of composite resin (A-1) and silica with a non-volatile content concentration of 50%. 100 parts of TMP3EOTA was added to this to prepare the coating agent of Example 5.

(Example 6) to (Example 11)
Coating agents of Examples 6 to 11 were prepared in the same manner as in Example 5, except that the composite resin (A), silica particles, reactive compound, and their blending amounts were changed to those shown in Tables 5 and 6.

Example 12
A coating agent of Example 12 was prepared by adding 35 parts of TMP3EOTA to 100 parts of the composite resin (A-5) (35 parts in terms of solid content).

(Example 13) to (Example 17)
The coating agents of Examples 13 to 17 were obtained in the same manner as in Example 12, except that the composite resin (A), reactive compound, and their blending amounts were changed to those shown in Tables 6 and 7.

(Comparative Example 2)
TMP3EOTA was used as the coating agent in Comparative Example 2.
(Comparative Example 3)
A mixture of 50 parts of TMP3EOTA and 50 parts of TCDDA was used as the coating agent in Comparative Example 3.
(Comparative Example 4)
A mixture of 50 parts of TMP3EOTA and 125 parts of MEK-ST-40 was used as the coating agent in Comparative Example 4.

<Production of Laminate>
The prepared coating agent was applied to a stretched polyethylene film (Hibron P manufactured by Tokyo Ink Co., Ltd.) having a thickness of 25 μm at a rate of 2 g/ ^m2 , and after volatilizing the solvent, the film was irradiated with an electron beam using an EB device at an energy intensity of 125,000 eV and an exposure dose of 50 kGy m/min. (kilogray) to form a coating layer.

<Evaluation>
(Adhesion to substrate)
A cellophane tape (TF-12 manufactured by Nichiban Co., Ltd.) was applied to the coating layer, and the degree of peeling when the tape was peeled off in one go was visually judged and rated on a three-point scale. Note that in Comparative Example 1, no coating layer was formed, so adhesion was not evaluated.
◯: No peeling △: Partial peeling ×: Complete peeling

(Heat resistance)
The laminate was brought into direct contact with the coating layer using a thermal gradient heat seal tester (manufactured by Tester Sangyo Co., Ltd.) at a sealing temperature of 140°C to 150°C, a pressure of 3 kg/ ^cm2 , and a time of 1 second. The condition of the film after contact with the heat seal bar was visually evaluated on a three-point scale.
◯: No wrinkles around the sealed area △: Slight wrinkles around the sealed area ×: Wrinkles clearly visible around the entire sealed area

(Recyclability)
The laminate cut into a size of 2 cm x 2 cm was placed in a 1.5% NaOH aqueous solution and stirred for 1 hour at 85° C. The laminate was then washed and dried, and the presence or absence of peeling of the coating layer was visually confirmed and evaluated on a four-point scale.
◎: Completely peeled off ◯: Almost completely peeled off △: Partially peeled off ×: No peeling

As is clear from the examples and comparative examples, the laminate of the present invention exhibits excellent adhesion, heat resistance, and recyclability.

Claims (11)

A method for producing a laminate including a heat seal layer, a stretched polyolefin film, and a coating layer in this order, comprising:
The method for producing a laminate includes applying a composition containing a composite resin (A) having a polysiloxane segment (a1) and a vinyl polymer segment (a2) and an active energy ray-curable monomer, and curing the composition by irradiating with active energy rays to form the coating layer. The method for producing a laminate according to claim 1, wherein the coating layer further contains inorganic particles (m). The method for producing a laminate according to claim 2, wherein the composite resin (A) and the inorganic particles (m) are bonded to each other via siloxane bonds in the polysiloxane segments (a1). The method for producing a laminate according to claim 1, wherein the active energy ray curable monomer includes a polyfunctional vinyl monomer having multiple vinyl reactive groups. The method for producing a laminate according to claim 1, wherein the glass transition temperature of the active energy ray-curable monomer is -30°C or higher and 250°C or lower. The method for producing a laminate according to claim 1, wherein the content of the active energy ray-curable monomer in the solid content of the composition is 1 to 85 mass %. The method for producing a laminate according to claim 1, wherein the active energy rays are electron beams. The method for producing a laminate according to claim 1, which has a primer layer disposed between the stretched polyolefin film and the coating layer and in contact with the coating layer. The method for producing a laminate according to claim 1, which has a printed layer disposed between the stretched polyolefin film and the coating layer. The method for producing a laminate according to claim 1, which has an adhesive layer disposed between the stretched polyolefin film and the heat seal layer, and a printing layer disposed between the stretched polyolefin film and the adhesive layer. A method for producing a packaging material, comprising producing a bag from a laminate obtained by the method for producing a laminate according to any one of claims 1 to 10.