JP2001220572A - Adhesive for preparing plastic film laminate metal plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive for polyester film laminate metal plates which does not generate oven fumes, shows a good shelf stability, adhesion processibility and retort resistance and may be used as a one-component type. SOLUTION: The adhesive for polyester film laminate metal plats contains (A) a polyorthoester prepared by allowing an orthoester such as an orthoformate, an orthoacetate, etc., to react with (b) at least one glycol compound chosen from an αglycol and a β-glycol and (c) a hydroxy group-containing compound having at least two hydroxy groups within a molecule, and (B) a polyisocyanate compound. In a preparation process of a polyester film laminate metal plate, a layer of the adhesive is sandwiched between a plastic film and a metal plate and subsequently heated to cure the adhesive layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive for a plastic film-laminated metal plate and a method for producing a plastic film-laminated metal plate using the adhesive.

[0002]

2. Description of the Related Art Conventionally, a metal plate (hereinafter, referred to as a "metallic plate") used for a beverage can or a food can.
A “PET laminated metal plate” is sometimes used for a polyester film (hereinafter referred to as “P”) via an adhesive.
ET film ") and a metal plate by thermocompression bonding. As an adhesive for a laminated metal plate, an epoxy resin-based or polyester resin-based adhesive is known.

However, the epoxy resin adhesive has a problem that a low molecular weight hardener component volatilizes when the adhesive is baked and hardened, and a large amount of oven fume is generated.

Further, the polyester resin adhesive is generally a two-pack type paint using a polyisocyanate compound as a cross-linking agent, which is inconvenient to handle.
There was a problem that the pot life was short. Further, in the polyester resin-based adhesive, it is preferable that the molecular weight of the polyester resin is large from the viewpoint of film appearance and performance of the laminated metal plate, but if the molecular weight is large, the viscosity increases and the compatibility with the crosslinking agent decreases. There's a problem.

An object of the present invention is to provide a one-pack type adhesive which has no problem of generation of oven fume, has good storage stability, and has good adhesion between a metal plate and a plastic film, and has good workability. Another object of the present invention is to provide a thermosetting adhesive for a polyester film-laminated metal plate capable of producing a plastic film-laminated metal plate having excellent performance such as retort resistance and film appearance.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, in a polyester resin-based adhesive, a hydroxyl group of a hydroxyl group-containing compound such as a polyester resin is converted into an orthoester. The inventors have found that the above object can be achieved by using a blocked polyorthoester, and have completed the present invention.

That is, the present invention provides: [A] (a)

[0008]

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In the formula, R ¹ is a hydrogen atom or a group having 1 to 1 carbon atoms.
Orthoesters represented by (b) α-glycol and β, wherein R ³ is the same or different and each represents an alkyl group having 1 to 4 carbon atoms.
A polyorthoester obtained by reacting at least one glycol compound selected from a glycol, and (c) a hydroxyl group-containing compound other than (b) having at least two hydroxyl groups in one molecule, and [B] It is intended to provide an adhesive for producing a plastic film-laminated metal plate, comprising a polyisocyanate compound.

Further, the present invention provides a method for producing a plastic film-laminated metal plate, comprising sandwiching the above-mentioned adhesive layer between a plastic film and a metal plate, and then heating to cure the adhesive layer. Is provided. Hereinafter, the present invention will be described in detail.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the adhesive of the present invention will be described in detail below. The components of the adhesive of the present invention are as follows.

Polyorthoester [A] The polyorthoester which is the component [A] in the composition of the present invention is a reaction product of an orthoester (a), a glycol compound (b) and a hydroxyl group-containing compound (c) described below. It is.

Orthoester (a): Orthoester (a) is represented by the following formula (1)

[0014]

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In the formula, R ¹ is a hydrogen atom or a group having 1 to 1 carbon atoms.
And R ³ is the same or different and each represents an alkyl group having 1 to 4 carbon atoms.

In the above formula (1), the alkyl group having 1 to 4 carbon atoms represented by R ¹ or R ² is linear or branched, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-
A butyl group and the like can be mentioned.

Specific examples of the orthoester (a) include:
For example, methyl orthoformate, ethyl orthoformate, propyl orthoformate, butyl orthoformate, methyl orthoacetate,
Examples thereof include ethyl orthoacetate, methyl orthopropionate, ethyl orthopropionate, methyl orthobutyrate, and ethyl orthobutyrate. Of these, methyl orthoformate, ethyl orthoformate, methyl orthoacetate, and ethyl orthoacetate are preferred. . These can be used alone or in combination of two or more.

Glycol compound (b): The glycol compound as the component (b) is at least one glycol compound selected from α-glycol and β-glycol having two hydroxyl groups in one molecule.

As the α-glycol, particularly, the following formula (2)

[0020]

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In the formula, R ³ , R ⁴ , R ⁵ and R ⁶ are the same or different and are each a hydrogen atom or a carbon atom having 1 to 24 carbon atoms.
An alkyl group, an aralkyl group having 7 to 24 carbon atoms or a phenyl group, or a group in which a part of these groups is substituted with an oxygen atom, and represented by R ³ , R ⁴ , R ⁵ and R ⁶ . The total number of carbon atoms of the group to be formed is in the range of 0 to 24, preferably 0 to 10, and R ⁴ and R ⁵ together with the carbon atom to which they are directly bonded form a cyclic structure. The compound represented by may be suitably used.

In the above formula (2), R ³ , R ⁴ , R ⁵
Or an alkyl group having 1 to 24 carbon atoms that can be represented by R ⁶ is linear, branched or cyclic, and includes methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, Pentyl, hexyl, n
-Octyl, 2-ethylhexyl, decyl, dodecyl,
Octadecyl, cyclohexyl, methylcyclohexyl, cyclohexylmethyl, cyclohexylethyl and the like can be mentioned.

In the above formula (2), R ³ , R ⁴ , R ⁵
Alternatively, as the aralkyl group having 7 to 24 carbon atoms that can be represented by R ⁶ , a phenyl-substituted alkyl group is preferable, and specific examples include a benzyl and phenethyl group.

In the above formula (2), R ³ , R ⁴ , R ⁵
Or a group in which part of an alkyl group, an aralkyl group or a phenyl group represented by R ⁶ is substituted with an oxygen atom, includes an alkoxyalkyl group such as methoxymethyl, ethoxymethyl, propoxymethyl and butoxymethyl; And alkanoyloxyalkyl groups such as acetoxyethyl; phenoxymethyl and phenoxyethyl groups. Equation (2) above
In the formula, R ³ , R ⁴ , R ⁵ or R ⁶ is preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

Thus, typical examples of the above α-glycol include, for example, ethylene glycol, 1,2-propylene glycol, 1,2-butylene glycol, 2,3
-Butylene glycol, 1,2-hexanediol,
Hydrolysis products of 1,2-dihydroxycyclohexane, pinacol, and long-chain alkyl monoepoxide; fatty acid monoglycerides (α-form) such as glycerin monoacetate (α-form) and glycerin monostearate (α-form); 3-ethoxypropane-1 , 2-diol, 3-phenoxypropane-1,2-diol, and the like.
Of these, ethylene glycol, 1,2
-Propylene glycol, 1,2-hexanediol are preferred.

On the other hand, as β-glycol, among others, the following formula (3)

[0027]

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In the formula, R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ and R ¹² are the same or different and are each a hydrogen atom or an alkyl group having 1 to 24 carbon atoms, or an alkyl group having 7 to 24 carbon atoms. An aralkyl group or a phenyl group, or a group in which a part of these groups is substituted with an oxygen atom, and R ⁷ , R ⁸ , R
^9, R ^10, a total of the number of carbon atoms of the groups represented by R ¹¹ and R ¹² in the range of 0-24, also R ⁷ and R ^9, or R ^7, R ⁹ and R ^11, these Which may form a cyclic structure together with the carbon atom directly bonded thereto, can be suitably used.

In the above formula (3), R ⁷ , R ⁸ , R
^9, R ^10, the alkyl group of R ¹¹ or 1 to 24 carbon atoms which is capable represented by R ^12, R ³ in the formula ^{(2), R 4, R} 5 or alkyl which may be represented by R ⁶ The same as mentioned above can be mentioned as the group.

In the above formula (3), R ⁷ , R ⁸ , R
^9, as the aralkyl group R ^10, R ¹¹ or 1 to 24 carbon atoms which is capable represented by R ^12, preferably an alkyl group which is phenyl substituted, specifically, for example, include benzyl, phenethyl groups be able to.

In the above formula (3), R ⁷ , R ⁸ , R
Examples of the group in which a part of the alkyl group, aralkyl group or phenyl group which can be represented by ⁹ , R ¹⁰ , R ¹¹ or R ¹² is substituted with an oxygen atom include, for example, methoxymethyl, ethoxymethyl, propoxymethyl, butoxy Alkoxyalkyl groups such as methyl; alkanoyloxyalkyl groups such as acetoxymethyl and acetoxyethyl;
Phenoxymethyl, phenoxyethyl groups and the like can be mentioned.

In the above formula (3), R ⁷ and R ⁹ , or R ⁷ , R ⁹ and R ¹¹ , as a cyclic structure which can be formed together with the carbon atom to which they are directly bonded, include cyclohexyl And cyclopentyl groups. R ⁷ , R ⁸ , R in the above formula (3)
^9, R ^10, R ¹¹ or R ¹² include, among others, is preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

Thus, typical examples of β-glycol include, for example, neopentyl glycol, 2-methyl-
1,3-propanediol, 2-methyl-2,4-pentanediol, 3-methyl-1,3-butanediol,
2-ethyl-1,3-hexanediol, 2,2-diethyl-1,3-propanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-butyl-2-ethyl-1,3 -Propanediol, 2-phenoxypropane-1,3-diol, 2-methyl-2-phenylpropane-1,3-diol, 1,3-propylene glycol, 1,3-butylene glycol, dimethylolpropionic acid, Methylolbutanoic acid, 2-ethyl-1,3
-Octanediol, 1,3-dihydroxycyclohexane; and fatty acid monoglycerides (β-form) such as glycerin monoacetate (β-form) and glycerin monostearate (β-form). Among these, neopentyl glycol, 2-methyl-1,3
-Propanediol, 2-methyl-2,4-pentanediol, 3-methyl-1,3-butanediol, 2-ethyl-1,3-hexanediol, 2,2-diethyl-
1,3-propanediol, 2,2,4-trimethyl-
1,3-pentanediol, 2-butyl-2-ethyl-
1,3-propanediol is preferred.

(C) Hydroxyl-containing compound: The hydroxyl-containing compound as the component (c) is a compound other than the above-mentioned glycol compound (b) having two or more hydroxyl groups in one molecule.

Examples of the hydroxyl group-containing compound (c) include compounds having two hydroxyl groups other than α-glycol and β-glycol or compounds having three or more hydroxyl groups in one molecule. Is 90-30,0
00, preferably in the range of 130 to 15,000 and a hydroxyl value of 4 to 1,850, preferably 8 to 1,6.
Those within the range of 50 are preferred.

Examples of the hydroxyl group-containing compound (c) include 1,4-butanediol, 1,4-dihydroxycyclohexane, 1,5-pentanediol, 1,6-hexanediol, 2,5-hexanediol, -Methyl-1,5-pentanediol, 1,4-dimethylolcyclohexane, tricyclodecanedimethanol, 2,
2-dimethyl-3-hydroxypropyl-2,2-dimethyl-3-hydroxypropionate [this corresponds to the ester of hydroxypivalic acid and neopentyl glycol], bisphenol A, bisphenol F, bis (4- (Hydroxyhexyl) -2,2-propane, bis (4-hydroxyhexyl) methane, 3,9-
Bis (1,1-dimethyl-2-hydroxyethyl)-
2,4,8,10-tetraoxaspiro [5,5] undecane, diethylene glycol, triethylene glycol, tetra- or higher polyethylene glycol, dipropylene glycol, tripropylene glycol, tetra- or higher polypropylene glycol, ethylene oxide and propylene oxide And copolymers having hydroxyl groups at both ends such as polycaprolactone diol, linear polyesters having hydroxyl groups at both ends such as polycaprolactone diol, polycarbonate diols, and carboxylic acid adducts of diepoxide.

Examples of the compound having three or more hydroxyl groups include glycerin, diglycerin, triglycerin, pentaerythritol, dipentaerythritol, sorbitol, mannitol, trimethylolethane, trimethylolpropane, and ditrimethylolpropane. , Tris (2-hydroxyethyl) isocyanurate, gluconic acid, polymers containing three or more hydroxyl groups (polyesters containing three or more hydroxyl groups, polyethers, acrylic polymers, ketone resins, phenolic resins, epoxy resins, urethanes Resins, polyvinyl alcohol which is a saponified product of polyvinyl acetate, natural saccharides such as glucose, etc.).

Among them, the hydroxyl group-containing compound (c) is 9
When it has a number average molecular weight in the range of 0 to 3,000, it is suitable that it has a hydroxyl value in the range of 60 to 1,850 mgKOH / g. When the number average molecular weight of the hydroxyl group-containing compound (c) is more than 3,000 and within the range of 30,000 or less, the hydroxyl group-containing compound (c) has a hydroxyl value of 4 to 60 mgKOH / g.
It is suitable that the hydroxyl group-containing polyester is in the range of

The hydroxyl group-containing polyester which can be suitably used as the hydroxyl group-containing compound (c) comprises an esterified product of a polybasic acid component and a polyhydric alcohol component. As the polybasic acid component, for example, phthalic anhydride, isophthalic acid, terephthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, succinic acid, fumaric acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, maleic anhydride , One or more dibasic acids selected from itaconic acid, dimer acid and the like, and lower alkyl esterified products of these acids are mainly used, and if necessary, benzoic acid, crotonic acid, pt-butyl benzoic acid, etc. A tribasic or higher polybasic acid such as monobasic acid, trimellitic anhydride, methylcyclohexenetricarboxylic acid, and pyromellitic anhydride is used in combination. Examples of the polyhydric alcohol component include ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol,
Neopentyl glycol, 3-methylpentanediol, 1,4-hexanediol, 1,6-hexanediol, cyclohexanedimethanol, hydrogenated bisphenol A, ethylene oxide adduct of bisphenol A,
A dihydric alcohol such as a propylene oxide adduct of bisphenol A is mainly used, and if necessary, a trihydric or higher polyhydric alcohol such as glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol can be used in combination. . These polyhydric alcohols can be used alone or in combination of two or more. Esterification or transesterification of both components can be carried out by a method known per se. For example, the polybasic acid component and the polyhydric alcohol component are mixed at 180 to 25%.
It can be obtained by polycondensation at a temperature of about 0 ° C.

After obtaining a polyester having a hydroxyl group from the polybasic acid component and the polyhydric alcohol component, maleic acid,
Polyesters having carboxyl groups introduced into the resin by reacting polybasic acids such as maleic anhydride, phthalic anhydride and trimellitic anhydride can also be used as the hydroxyl group-containing polyester.

Production of polyorthoester: In producing the polyorthoester which is the component [A] in the composition of the present invention, the mixing ratio of the orthoester (a), the glycol compound (b) and the hydroxyl group-containing compound (c). Is not particularly limited, but the amount of the orthoester (a) is 0.01 to 10 mol, preferably 0.05 to 5 mol, relative to 1 equivalent of the hydroxyl group in the hydroxyl group-containing compound (c). More preferably, it is in the range of 0.1 to 2 mol, and the amount of the glycol compound (B) is 0.01 to 10 mol, preferably 0.05 to 5 mol, more preferably 0.1 to 2 mol.
It is appropriate to use the compound in a molar ratio within a range from the viewpoint of easy control of the molecular weight.

The polyorthoester [A] can be obtained by subjecting the three components (a), (b) and (c) to a condensation reaction. For example, the above three components are optionally subjected to a condensation reaction in the presence of an organic solvent and an acid catalyst, usually at room temperature to 250 ° C, preferably at a temperature in the range of 70 to 200 ° C for about 1 to 20 hours. Thereby, it can be suitably manufactured.

In the present invention, the alkoxy group of the orthoester (a) undergoes an exchange reaction with the alcohol part of the glycol compound (b) and the hydroxyl group-containing compound (c).
At that time, the orthoester (a) usually reacts preferentially with α-glycol or β-glycol, which is a glycol compound (b) having an adjacent hydroxyl group, to form a cyclic structure. That is, the glycol compound (b) is preferentially reacted with the two functional groups (alkoxyl groups) of the trifunctional orthoester (a) to cyclize. The remaining one alkoxy group of the orthoester (a) can react with the hydroxyl group-containing compound (c). Thus, since the polyorthoester [A] does not involve a bridge between molecules in the production thereof, the molecular weight and the viscosity can be suppressed. On the other hand, the orthoester (a) and the hydroxyl group-containing compound (c) are used without the presence of the glycol compound (b).
Is directly reacted with each other, a cross-linking reaction occurs between molecules, and the molecular weight and viscosity of the product increase steadily. The polyorthoester [A] in the composition of the present invention is obtained by adding the glycol compound (b) to the orthoester (a) and the hydroxyl group-containing compound (c) and reacting them, thereby suppressing an increase in molecular weight or viscosity. It is.

The polyorthoester [A] produced as described above is, for example, an orthoester of the formula (1), an α-glycol of the formula (2) and two hydroxyl groups in one molecule. When the compound having the above formula is used as a raw material, the following formula (4)

[0045]

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In the formula, Y ¹ represents a residue obtained by removing two hydroxyl groups from a compound having two hydroxyl groups in one molecule;
¹ , R ³ , R ⁴ , R ⁵ and R ⁶ are as defined above,
In addition, when the orthoester of the formula (1), the β-glycol of the formula (3) and a compound having four hydroxyl groups in one molecule are used as a raw material, The following equation (5)

[0047]

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In the formula, Y ² represents a residue obtained by removing four hydroxyl groups from a compound having four hydroxyl groups in one molecule;
¹ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ and R ¹² can have a structure as defined above.

Polyisocyanate compound [B] The polyisocyanate compound [B] is a curing agent capable of forming a cured product by reacting with a hydroxyl group generated by hydrolysis of the orthoester group of the polyorthoester [A]. It is a component that works as

The polyisocyanate compound includes:
Aliphatic diisocyanates such as hexamethylene diisocyanate and trimethylhexamethylene diisocyanate; cyclic aliphatic diisocyanates such as hydrogenated xylylene diisocyanate and isophorone diisocyanate; aromatic diisocyanates such as tolylene diisocyanate and 4,4'-diphenylmethane diisocyanate; Triphenylmethane-4,4 ', 4 "-triisocyanate, 1,3,5-triisocyanatobenzene, 2,4,6-triisocyanatotoluene, 4,4'
Organic polyisocyanate itself such as a polyisocyanate compound having three or more isocyanate groups such as -dimethyldiphenylmethane-2,2 ', 5,5'-tetraisocyanate, or each of these organic polyisocyanates and a polyhydric alcohol And low molecular weight polyester resins or adducts with water or the like, cyclized polymers of the above-mentioned organic polyisocyanates, and isocyanate / biuret bodies. Of these, isocyanurate obtained by cyclopolymerization of hexamethylene diisocyanate is preferably used.

Polyester Resin (C) The polyester resin (C) is a hydroxyl group-containing polyester resin which is optionally added to the adhesive of the present invention.
１５15 mgKOH / g, preferably 3〜１０10 mgKOH
/ G in the range of 5,000 to 30,00 / g
It has a number average molecular weight in the range of 0, preferably 9,000 to 20,000. Further, the glass transition temperature is 0 to 100.
C., preferably in the range of 35 to 90.degree.

When the number average molecular weight of the polyester resin [C] is within the above range, a plastic film laminated metal plate having good adhesiveness and good flexibility at the time of curing of the adhesive layer obtained by curing is obtained. The adhesive workability is not problematic, and if the hydroxyl value is within the above range, the storage stability can be set to a practical range even if the adhesive is a one-pack type, and the curability is also good. An adhesive can be obtained. Further, when the glass transition temperature of the polyester resin is within the above range, the adhesive layer obtained by drying is easily tack-free, and the coating workability can be improved.

Adhesive of the Present Invention The adhesive of the present invention contains the orthoester [A] and the polyisocyanate compound [B] as essential components, and contains the polyester resin [C] as necessary.
[A], per 100 parts by weight of the total of the components [B] and [C], the compounding amount of each component is within the following range, curability, adhesion, retort resistance, plastic film laminate metal plate It is suitable in terms of workability and the like. [A] component: 10 to 99 parts by weight, preferably 30 to 90 parts by weight
Parts by weight, [B] component: 1 to 30 parts by weight, preferably 5 to 20 parts by weight, [C] component: 0 to 80 parts by weight, preferably 0 to 65 parts by weight.

The adhesives of the present invention include the above [A] and [B]
And if necessary, other than the component [C], if necessary, for example, a polyfunctional epoxy resin, a blocked polyisocyanate compound, a polyvinyl compound, an antiblocking agent, a coloring pigment, a curing catalyst, and lubricity. An imparting agent, an organic solvent, a silane coupling agent, an antifoaming agent, an antistatic agent, and the like can be appropriately compounded.

The above-mentioned polyfunctional epoxy resin, which can be added to the adhesive of the present invention as required, can improve the adhesiveness to a metal plate, the heat resistance of the adhesive, and the Pt by retort treatment.
It can contribute to prevention of whitening of the ET laminated metal plate. As a multifunctional epoxy resin, processability,
Bisphenol type epoxy resin from the viewpoint of heat resistance, etc.
Phenol novolak type epoxy resin or cresol novolak type epoxy resin has a number average molecular weight of 350 to 4,
Those within the range of 000 are preferably used, and among them, novolak type epoxy resins are particularly suitable. Commercial products of the novolak type epoxy resin include, for example, Epototo YDCN-701, -702, -703, and -704 (all manufactured by Toto Kasei Co., Ltd.). When blending the above polyfunctional epoxy resin, the blending amount is preferably 30 parts by weight or less per 100 parts by weight of the total of the components [A], [B] and [C].

The blocked polyisocyanate compound which can be added to the adhesive of the present invention if necessary is
It is a compound obtained by blocking the isocyanate group of the polyisocyanate compound [B] with a blocking agent. Examples of the blocking agent include phenols such as phenol, cresol and xylenol; ε-caprolactam, δ-valerolactam, γ-butyrolactam, β-
Lactams such as propiolactam; methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, tert-butyl alcohol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, benzyl alcohol, etc. Alcohols; formamidoxime, acetoaldoxime,
Oximes such as acetoxime, methyl ethyl ketoxime, diacetyl monooxime, benzophenone oxime and cyclohexanone oxime; dimethyl malonate, diethyl malonate, ethyl acetoacetate, methyl acetoacetate,
A blocking agent such as an active methylene type such as acetylacetone can be used. When the blocked polyisocyanate compound is blended, the blending amount is usually preferably 25 parts by weight or less per 100 parts by weight of the total of the components [A], [B] and [C].

The above-mentioned polyvinyl compound, which can be added to the adhesive of the present invention as required, is used as needed when the adhesive of the present invention is cured by using both heating and electron beam irradiation. Is a compound having two or more polymerizable unsaturated groups polymerizable by electron beam irradiation in the molecule, among which the number average molecular weight is 300 to 5,000,
Polyester oligomers having a polymerizable unsaturated group of 0.3 to 12 equivalents / kg molecule are preferred.

Specific examples of the polyester oligomer include those obtained by esterifying a polymerizable unsaturated carboxylic acid such as acrylic acid or methacrylic acid to a dihydric or higher alcohol or a molecular weight polyester polyol.

When the above-mentioned polyvinyl compound is blended, the blending amount is 1% of the total of the components [A], [B] and [C].
Usually, a range of 20 parts by weight or less per 100 parts by weight is preferable.

The anti-blocking agent, which can be added to the adhesive of the present invention as required, is prepared by winding a laminated film for laminating a metal plate into a coil and applying the adhesive layer of the coil and the adhesive. It is blended as necessary for the purpose of preventing the non-coated surface of the uncoated PET film from adhering and causing blocking.

Examples of the anti-blocking agent include extenders such as silica fine powder, barium sulfate, calcium carbonate, talc, mica, and clay; polyolefin fine particles such as maleated polypropylene fine particles and polypropylene fine particles, nylon fine particles, and acrylic resin fine particles. And organic resin fine particles such as polytetrafluoroethylene fine particles. The organic resin fine particles preferably have a particle diameter in the range of 0.1 to 40 μm, preferably 0.1 to 15 μm.

When the above anti-blocking agent is blended,
The compounding amount is preferably in the range of usually 60 parts by weight or less per 100 parts by weight of the total of the components [A], [B] and [C].

Examples of the coloring pigment which can be added to the adhesive of the present invention as required include white pigments such as titanium oxide and other chromatic pigments. PET
When a laminated metal plate is used on the outer surface of a can, multicolor printing is usually performed and a colored layer (usually a white coat) is required under the printing ink layer. The use of is very advantageous because one manufacturing step can be omitted. The amount of the coloring pigment is not particularly limited as long as the performance of the adhesive layer is not impaired.However, per the total of 100 parts by weight of the components (A), (B) and (C), usually, It is preferable to mix in a quantitative range of 300 parts by weight or less.

The curing catalyst which can be blended with the adhesive of the present invention as required is a catalyst blended to promote crosslinking of the adhesive by heating. For example, tin octylate, dibutyltin dibutyltin (2-ethylhexanoate), dioctyltin di (2-ethylhexanoate),
Examples thereof include organometallic catalysts such as dibutyltin dilaurate, dibutyltin oxide, dioctyltin oxide, and lead 2-ethylhexanoate. When a curing catalyst is compounded, the compounding amount is usually 0.01 parts by weight per 100 parts by weight of the total of the components [A], [B] and [C].
A range of from 5 to 5 parts by weight is preferred.

The lubricity-imparting agent, which can be optionally added to the adhesive of the present invention, is used for imparting lubricity to the surface of the adhesive. It is compounded for the purpose of preventing. Examples of the lubricity imparting agent include fatty acid ester wax; polyolefin wax such as polyethylene wax; animal wax such as lanolin and beeswax; plant wax such as carnauba wax and water wax; microcrystalline wax; Waxes such as fluorine-based wax can be exemplified. When the lubricating agent is compounded, the compounding amount is preferably in the range of usually 0.01 to 10 parts by weight per 100 parts by weight of the total of the components (A), (B) and (C). It is.

The above-mentioned organic solvent which can be added to the adhesive of the present invention if necessary is added for the purpose of improving the workability of applying the adhesive to a plastic film, and the like. Those which can dissolve or disperse the binder component and do not react with the polyisocyanate compound [B], for example, aromatic hydrocarbons such as toluene, xylene, Solvesso # 150 (manufactured by Esso Oil Co., Ltd., high boiling aromatic petroleum solvent) Hydrogen solvents, ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, and ester solvents such as ethyl acetate, butyl acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, and ethylene glycol monoethyl ether acetate. Bets can be, can be used to select at least one kind of them appropriately.

Next, a method for producing a plastic film laminated metal plate using the adhesive of the present invention will be described.
In the production method of the present invention, a layer of the adhesive of the present invention is sandwiched between a plastic film and a metal plate, and then heated to cure the adhesive layer, thereby producing a plastic film laminated metal plate.

The plastic film can be used without any particular limitation as long as it has strength, heat resistance and the like. Among them, a polyester film can be suitably used. As the polyester film, particularly, a film in which 75 to 100% of the ester repeating units are composed of ethylene terephthalate units is preferable. Examples of the ester unit other than the ethylene terephthalate unit include ester units such as phthalic acid, isophthalic acid, succinic acid, and adipic acid. The surface of the polyester film is preferably subjected to a surface treatment such as a corona discharge treatment in order to improve the adhesion to an adhesive or ink.

The thickness of the plastic film is not particularly limited, but is usually 5 to 30 μm.
m can be suitably used. An ink layer may be formed on the surface of the plastic film as needed. As the ink used for forming the ink layer, any known printing ink used for printing packaging films can be used without particular limitation, and the printing ink is applied by the same method as that for printing packaging films. Can be. The type of printing ink is preferably a cross-linkable heat-resistant ink, and examples thereof include polyester resin-based, acrylic resin-based, and alkyd resin-based inks.

Examples of the metal plate to be bonded to the plastic film include a hot-rolled steel plate, a cold-rolled steel plate, a galvanized steel plate, an electro-galvanized steel plate, an iron-zinc alloy-plated steel plate, a zinc-aluminum alloy-plated steel plate, and a nickel-plated steel plate. Metal plate material such as zinc alloy plated steel plate, nickel-tin alloy plated steel plate, tinplate, chrome plated steel plate, aluminum plated steel plate, turn plated steel plate, nickel plated steel plate, stainless steel, tin-free steel, aluminum plate, copper plate, titanium plate; Chemical conversion treatments, such as phosphate treatment, chromate treatment, composite oxide film treatment, etc., on these metal plate materials; primers such as white coat on the surfaces of these metal plate materials or the chemical conversion treatment metal plates A coated metal plate such as a primer-coated metal plate with a layer Can. In the present invention,
The “metal plate” includes a flat metal plate such as the above-mentioned metal plate material, chemical conversion-treated metal plate or primer-coated metal plate, and also includes a processed metal plate molded into a can body or the like.

The method for sandwiching the adhesive layer between the metal plate and the plastic film is as follows. (1) An adhesive is applied to a metal plate to form an adhesive layer, and a plastic film is laminated thereon. And (2) a method in which an adhesive is applied to a plastic film to form an adhesive layer, and a metal plate is laminated thereon. Among them, the method (2) is preferable from the viewpoint of ease of production.

As a method for producing a plastic film laminated metal plate using the method (2), for example, the adhesive of the present invention is applied to the plastic film by a roll coater method, a gravure method, a gravure offset method, a spray method, or the like. By a coating method such as a coating method, a coating method known per se is usually applied so that the dry film thickness is about 0.3 to 15 μm, and if necessary, a tack-free state is obtained, for example, at 50 to 180 ° C. There is a method in which a plastic film having an adhesive layer is obtained by drying at a temperature, and a metal plate is bonded to the plastic film having the adhesive layer.

The step of bonding a metal plate to the plastic film having the adhesive layer can be carried out continuously immediately after obtaining the plastic film having the adhesive layer. Is wound up in a coil form and stored until the time of lamination to a metal plate, at which point the coil is unwrapped and the metal plate is generally laminated to a plastic film having the adhesive layer. I have.

The condition for bonding the metal plate to the surface of the adhesive layer of the plastic film having the adhesive layer is such that the plastic film is not deteriorated, the plastic film and the metal plate are sufficiently bonded to each other via the adhesive layer, and There is no particular limitation as long as a plastic film-laminated metal plate having a good appearance can be obtained. As an example of the bonding conditions, for example, the temperature of the metal plate at the time of thermocompression bonding by a method using a heating roll or a method of preheating the metal plate is set to about 120 to 20.
A method of laminating a metal plate and a plastic film having an adhesive layer by heating and pressing at 0 ° C. for a short time (usually about 2 seconds or less) can be mentioned. When a flat metal plate is used, a plastic film having an adhesive layer on one or both sides of the flat metal plate can be heat-laminated.

The adhesive layer of the plastic film-laminated metal plate obtained as described above can be separately heated and thermally cured. However, in some cases, a post-lamination process such as welding in a can-making process can be used. It can also be heat-cured by baking the repair paint film of the part or by baking the paint film on the inner surface of the can. The baking conditions in the case of the above-mentioned separate heating and heat curing are such that the adhesive layer is thermally cured and the plastic film is not deteriorated, for example, 30 to 120 seconds so that the maximum temperature of the metal plate becomes 180 to 230 ° C. Baking is preferred.

The plastic film-laminated metal plate obtained by the production method of the present invention is suitably used for cans such as beverage cans, food cans, miscellaneous cans, and 5 gallon cans, and for metal lids such as caps. It can also be applied to the outer surfaces of household appliances such as bottles and refrigerators.

[0077]

The present invention will be described more specifically with reference to the following examples. Hereinafter, both “parts” and “%” are based on weight.

Synthesis of Polyester Synthesis Example 1 31 parts of ethylene glycol, 27 parts of 1,3-butanediol, 19.4 parts of trimellitic anhydride, 49 parts of isophthalic acid were placed in a reaction vessel equipped with a stirrer, a rectification tower and a thermometer. .8
Parts, 29.5 parts of terephthalic acid and 0.2 parts of dibutyltin dioxide, and the esterification reaction was carried out while blowing the inert gas so that the rectification column temperature did not exceed 110 ° C. When 2/3 was distilled, it was cooled once. Then, after adding 33.2 parts of isophthalic acid and 36.9 parts of terephthalic acid, the temperature was raised to 250 ° C. and an esterification reaction was performed to obtain a polyester a. Polyester a had a hydroxyl value of 141 mgKOH / g and a number average molecular weight of 1,600.

Synthesis Examples 2 to 4 Synthesis was performed in the same manner as in Synthesis Example 1 except that the composition was changed as shown in Table 1 below to obtain each polyester. The hydroxyl value and number average molecular weight of each of the obtained polyesters are shown in Table 1 below.

[0080]

[Table 1]

[0081] Preparation Example polyorthoesters 1 stirrer, condenser, reactor having a temperature control device and a solvent recovery apparatus, 424 parts of methyl orthoformate, 2-butyl-2-ethyl-1,3-propane 640 parts of a diol, 136 parts of pentaerythritol and 4 parts of a 90% formic acid aqueous solution were charged, and the mixture was maintained at about 85 ° C. for 1 hour while distilling off methanol produced by the alcohol exchange reaction. afterwards,
The temperature was raised to 190 ° C. over 2 hours to recover 365 parts of methanol, and the colorless and transparent liquid polyorthoester (A
-1) was obtained. The resulting polyorthoester had a Gardner viscosity X ⁺ and a weight average molecular weight of 1,540.

Production Examples 2 to 5 Reactions were carried out in the same manner as in Production Example 1 except that the raw material compositions to be blended were as shown in Table 2 below to obtain polyorthoesters.

[0083]

[Table 2]

Preparation of Adhesive Composition Example 1 40 parts of the polyorthoester (A-1) obtained in Production Example 1
"Elitel UE3200" (trade name, manufactured by Unitika Ltd.)
Polyester resin, number average molecular weight 16,000, Tg point 65 ° C, hydroxyl value 6 mgKOH / g) 60 parts, “Duranate TPA100” (trade name, manufactured by Asahi Kasei Corporation)
A mixed solvent (methyl ethyl ketone / toluene = 50/50) was mixed with 15 parts of hexamethylene diisocyanate-based polyisocyanate compound and 0.5 part of dibutyltin dilaurate.
(Weight ratio)) and dispersed therein to obtain a nonvolatile content of 30% and a viscosity of 2.
An adhesive of 3 seconds (measured with a # 3 Zahn cup at 25 ° C.) was obtained.

Examples 2 to 5 and Comparative Examples 1 to 3 Each adhesive was prepared in the same manner as in Example 1, except that the raw material composition to be mixed and dispersed in the mixed solvent was as shown in Table 3 below. I got The nonvolatile content (%) and viscosity (the number of seconds measured by # 3 Zahn cup at 25 ° C.) of each of the obtained adhesives are shown in Table 3 below. In addition, the compounding quantity in Table 3 is a display by solid content weight.

In Table 3, (Note) has the following meaning. (* 1) Duranate TPA-B80E: trade name
Asahi Kasei Kogyo Co., Ltd., hexamethylene diisocyanate-based blocked polyisocyanate compound, solid content about 80
%.

For each of the adhesives obtained in Examples 1 to 5 and Comparative Examples 1 to 3, the pot life,
Blocking resistance, lamination suitability, lamination strength,
A workability test was performed. The results of these tests are shown in Table 3 below.

Test Method Pot Life: The state of the adhesive composition when each adhesive composition was stored in a room at 50 ° C. for 4 days was investigated and evaluated according to the following criteria. ：: Viscosity after storage (measured at Zahn cup # 3/25 ° C.) is within 1.5 times the number of seconds of the initial viscosity. Δ: Flows at 25 ° C., but viscosity cannot be measured with Zahn cup # 3. ×: 25 Does not flow at ° C.

Blocking resistance: Each adhesive composition was coated on a 12 μm-thick polyethylene terephthalate film (P
ET film) has a dry film thickness of about 5μ on the corona discharge treated surface.
m so that the ambient temperature is 120 ℃
For 1 minute. Another PET film is placed on the dried coating so that the non-treated surface faces the dried coating, and a pressure of 10 kg / cm ² is applied to the room at a temperature of 25 ° C. and a humidity of 60% RH. For 3 days. Cut this storage laminate film to a width of 30 mm,
The film is pulled from the dried coating surface at a pulling speed of 500 mm / min.
The peel strength (g / 30 mm) when peeled at 80 degrees was measured and evaluated according to the following criteria. ：: peel strength of less than 20 g / 30 mm, Δ: peel strength of 20 g / 30 mm or more and 50 g / 30 m
m: ×: Peel strength is 50 g / 30 mm or more.

Lamination suitability: Using the storage laminate film prepared in the above-described blocking resistance test, another PET film covering the dried coating film surface was peeled off from the storage laminate film, and a plate was applied to the dried coating film surface that appeared. The appearance of a PET laminated tin plate obtained by laminating a 0.2 mm thick tin plate at a lamination temperature of 160 ° C., a linear pressure of 50 kg, and a speed of 200 m / min was evaluated according to the following criteria. ：: No abnormality was observed on the PET laminated surface. Δ: Slight skin was observed on the PET laminated surface. ×: Marked skin was significantly observed on the PET laminated surface.

Lamination strength: The PET laminated tin plate prepared for the above-mentioned lamination suitability test was 15 m long.
The sheet was cut to a width of m, and a peel test between the PET film and the tin plate was performed to evaluate the difficulty of peeling according to the following criteria. ：: PET film is not peeled, Δ: PET film is partially peeled, but PET film is cut off in the middle, ×: PET film is entirely peeled.

Processability: PET obtained by baking the PET laminated tin plate prepared in the above-mentioned lamination suitability test for 1 minute under the condition that the maximum temperature of the tin plate becomes 200 ° C.
A laminate tin plate was pressed by a 200 end processing machine (can lid processing machine) with the tin plate side up, and the peeling state of the PET film around the can lid was evaluated according to the following criteria. ：: No peeling of the PET film was observed. Δ: Part of the PET film in the peripheral area was peeled off. ×: PET film in the peripheral area was peeled all around.

[0093]

[Table 3]

[0094]

The adhesive of the present invention has no storage fume problem, has good storage stability, and can be made into a one-part adhesive. By using the adhesive of the present invention, a plastic film-laminated metal plate having good adhesion between a metal plate and a plastic film, good performance such as workability and retort resistance, and good film appearance can be produced.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takashi Isaka 4-171-1, Higashi-Hachiman, Hiratsuka-shi, Kanagawa Prefecture Inside Kansai Paint Co., Ltd. (72) Inventor Yoshizumi Matsuno 4-171-1, Higashi-Hachiman, Hiratsuka-shi, Kanagawa Kansai Paint Co., Ltd. (72) Inventor Hirohiko Aida 4-171-1, Higashiyawata, Hiratsuka-shi, Kanagawa F Kansai Paint Co., Ltd. F-term (reference) 4J040 EF051 EF111 EF291 EF301 EF321 JA12 JB02 LA01 LA05 LA06 MA02 MA10 MB03 NA08 PA30

Claims (9)

[Claims] [A] (a) (a) The following formula (1) In the formula, R ¹ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and three R ^{2 s} are the same or different and each represent an alkyl group having 1 to 4 carbon atoms. (B) at least one glycol compound selected from α-glycol and β-glycol, and (c) a hydroxyl group-containing compound other than (b) having at least two hydroxyl groups in one molecule. An adhesive for producing a plastic film-laminated metal sheet, comprising: a polyorthoester; and [B] a polyisocyanate compound. 2. The adhesive according to claim 1, wherein the orthoester (a) is at least one compound selected from methyl orthoformate, ethyl orthoformate, methyl orthoacetate and ethyl orthoacetate. 3. The method according to claim 1, wherein the hydroxyl group in the hydroxyl group-containing compound (c) is
The adhesive according to claim 1, wherein the adhesive is at least partially blocked by a 5- or 6-membered orthoester composed of an orthoester (a) and a glycol compound (b). 4. . 4. The compound (c) having a hydroxyl group content of 90 to 3
Number average molecular weight in the range of 000 and 4-1850
The adhesive according to any one of claims 1 to 3, wherein the adhesive has a hydroxyl value within a range of mgKOH / g. 5. The compound (c) having a hydroxyl group of 90 to 3,
Number average molecular weight in the range of 000 and 60-1,850 m
The adhesive according to claim 4, having a hydroxyl value within the range of gKOH / g. 6. The compound (c) having a hydroxyl group content of 3,000.
And a molecular weight in the range of not more than 30,000 and from 4 to
The adhesive according to claim 4, which is a hydroxyl-containing polyester having a hydroxyl value in the range of 60 mgKOH / g. 7. It further comprises a hydroxyl-containing polyester resin [C] having a hydroxyl value in the range of 2 to 15 mgKOH / g and a number average molecular weight in the range of 5,000 to 30,000. The adhesive according to claim 5. 8. The mixing ratio of the polyorthoester [A], the polyisocyanate compound [B] and the hydroxyl group-containing polyester resin [C] is 100 parts by weight in total of the solid contents of the components [A], [B] and [C]. The component (A) is based on
The adhesive according to any one of claims 1 to 7, wherein 99 parts by weight, the component (B) is in the range of 1 to 20 parts by weight, and the component (C) is in the range of 0 to 60 parts by weight. 9. The method according to claim 1, wherein the adhesive layer according to claim 1 is sandwiched between a plastic film and a metal plate, and then heated to cure the adhesive layer. Of manufacturing a plastic film laminated metal sheet.