JP2003013001A - Ultraviolet light-curing type coating material composition for can and method for producing coated metal can - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To be excellent in coating performance such as workability, adhesion, hardness, and scratch resistance, which can be cured by ultraviolet irradiation with a low irradiation amount, and in particular, coating appearance and retort resistance. A UV-curable can coating composition capable of forming an excellent coating film, and a coated metal can using this composition. SOLUTION: The compound (A) having an alicyclic epoxy group in the molecule and not having an ester bond is 10 to 100 parts by weight, and having an alicyclic epoxy group in the molecule and having an ester bond. The glycidyl group and / or the alicyclic ring in the molecule are based on 0 to 90 parts by weight of the compound and / or the epoxy compound (B) having a glycidyl group and 100 parts by weight of the total amount of the compounds (A) and (B). 1 to 50 parts by weight of a copolymer having at least one epoxy group of the formula, and a cationic polymerization initiator which generates a cation by irradiation with ultraviolet light.
An ultraviolet-curable can coating composition containing from 0.01 to 20 parts by weight.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a coating which can be cured by irradiation with ultraviolet rays and which is excellent in coating properties such as processability, adhesion, hardness and scratch resistance, and particularly excellent in coating appearance and retort resistance. The present invention relates to an ultraviolet-curable can coating composition capable of forming a film, and a method for producing a coated metal can using the composition.

[0002]

2. Description of the Related Art Conventionally, as an ultraviolet curable coating composition, a cationically polymerizable coating composition containing a cationically polymerizable compound having an epoxy group or a vinyl group and a cationic polymerization initiator capable of generating a cation upon ultraviolet irradiation, and a radical polymerization There is known a radical-polymerizable coating material containing a radical-polymerizable compound having a polymerizable unsaturated group and a radical-polymerization initiator that generates a radical upon irradiation with ultraviolet rays.

[0003]

However, the radical polymerization type coating composition is characterized by a relatively high curing speed, but on the other hand, it has insufficient adhesion to the material and workability, and also has a curing inhibition by oxygen. Therefore, the surface curability is poor,
In particular, when using a thin film (2 to 8 μ), there is a problem that equipment such as nitrogen filling is required. On the other hand, the cationic polymerization type paint has the advantages that it has better adhesion to the material and workability than the radical polymerization type paint, and that it does not require equipment such as nitrogen encapsulation. Since it is slow, there is a problem that the coating performance, particularly the coating appearance and retort resistance, are insufficient.

Also, all of the polymerizable coatings have a low irradiation dose (1
If it is less than 00 mJ / cm ² , there is a problem that the curability is insufficient. This is because, for example, an alicyclic epoxy suitable for cationic curing often has an ester bond in the molecule, but the ester bond may react with a cationic species to hinder the polymerization of the epoxy. There is. For example, JP-A-10-158581 discloses an ultraviolet-curable type compound containing a compound having an alicyclic epoxy group in the molecule, a compound having an oxetane ring in the molecule, a specific copolymer, and a cationic polymerization initiator. Although a coating composition for a can is described, there are problems such as hardness in hot water, appearance of coating film, and impact resistance related to retort resistance due to the above reasons.

[0005]

Therefore, the inventors of the present invention can form a thin film without needing equipment such as nitrogen encapsulation and can be cured by irradiation with ultraviolet rays at a low irradiation amount, which is required as a paint for cans. Processability, adhesiveness, hardness, excellent coating film performance such as scratch resistance, especially coating film appearance, it is possible to form a coating film excellent in retort resistance, and after heating after irradiation with ultraviolet rays, An intensive study was conducted for the purpose of obtaining an ultraviolet-curable coating composition capable of forming a coating film exhibiting excellent in-water hardness. As a result, the present inventors have found that the above object can be achieved by using a predetermined amount of an alicyclic epoxy having a specific structure, and have completed the present invention.

That is, the first aspect of the present invention comprises 10 to 100 parts by weight of a compound (A) having an alicyclic epoxy group in the molecule and not having an ester bond, and an alicyclic epoxy group in the molecule. And an epoxy compound (B) having a glycidyl group and a compound having an ester bond 0 to 90
Copolymers (C) 1 to 5 having at least one glycidyl group and / or alicyclic epoxy group in the molecule, relative to 100 parts by weight of the total amount of the compounds (A) and (B) by weight.
A UV-curable coating composition for a can, which contains 0 part by weight and 0.01 to 20 parts by weight of a cationic polymerization initiator (D) that generates a cation upon irradiation with ultraviolet rays. A second aspect of the present invention provides the ultraviolet-curable can coating composition according to the first aspect of the present invention, wherein the compound (A) is an epoxy compound represented by the following general formula (I). .

[0007]

[Chemical 2]

(In the formula, X is an oxygen atom, a sulfur atom, --SO
^{-, - SO 2 -, -} CH 2 -, - C (CH 3) 2 -, - CBr 2 -, - C
(CBr ^{3) 2} -, or ^{-C (CF 3) 2 -,} - C (CCl 3) 2 -, - C
H (C ₆ H ₅ ) -divalent group or a mere single bond connecting two alicyclic rings, R ^{1 to} R ¹⁸ may be the same or different, and these are hydrogen. A hydrocarbon group which may contain an atom, a halogen atom, an oxygen atom or a halogen atom, or an alkoxy group which may have a substituent. ) In the third aspect of the present invention, the copolymer (C) is a copolymer of a glycidyl group-containing polymerizable unsaturated monomer and / or an alicyclic epoxy group-containing polymerizable unsaturated monomer and another polymerizable unsaturated monomer. A UV-curable can coating composition according to the first aspect of the present invention, which is a united body. The fourth aspect of the present invention is to further add a lubricity imparting agent to the compounds (A) and (B).
0.01 to 10 parts by weight per 100 parts by weight of the total amount is provided, and the ultraviolet-curable can coating composition according to the first or second aspect of the present invention is provided. Fifth of the present invention
Is further contained in an amount of 0.1 to 50 parts by weight, based on 100 parts by weight of the total amount of the compounds (A) and (B), in any one of the first to fourth aspects of the present invention. There is provided the ultraviolet-curable can coating composition described above. A sixth aspect of the present invention applies the ultraviolet-curable coating composition for a can according to any one of the first to fifth aspects of the present invention to a metal plate, a resin film laminated metal plate or a metal can formed by molding these metal plates. Then, there is provided a method for producing a coated metal can, which comprises irradiating with ultraviolet rays to cure.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The ultraviolet-curable coating composition for a can of the present invention is a coating composition capable of undergoing cationic polymerization upon irradiation with ultraviolet rays to be cured, and each component of this composition will be described below.

(Compound (A) having an alicyclic epoxy group in the molecule) A compound (A) having an alicyclic epoxy group in the molecule and having no ester bond used in the present invention
(Hereinafter, it may be abbreviated as "epoxy compound (A)".) Includes the epoxy compound represented by the above general formula (I). The alicyclic epoxy compound represented by the above general formula (I) is produced by oxidizing an alicyclic olefin compound represented by the following general formula (II) with a substantially anhydrous aliphatic percarboxylic acid. It

[0011]

[Chemical 3]

(In the formula, X and R ^{1 to} R ¹⁸ have the same meanings as in the general formula (1).)

The alicyclic olefin compound used as a raw material is generally synthesized by a dehydration reaction of a compound having a corresponding hydroxyl group. A method for producing an alicyclic olefin compound is described in JP-A-48-29899 and JP-A-58-1.
As described in JP-A-72387 and JP-A-2000-169399, it can be synthesized from a compound having a cyclohexanol structure, for example. As can be seen from the formula (II), the obtained alicyclic olefin compound preferably has a double bond at the 3 and 4 positions with respect to the substituent X, and has a hydroxyl group which is a raw material of the alicyclic olefin compound. The compound having a hydroxyl group at the 4-position with respect to the substituent X is preferable. Examples of these compounds include those obtained by a dehydration reaction of a compound containing at least two cyclohexane rings having hydroxyl groups bonded in the molecule.

Examples of the compound containing at least two cyclohexane rings having hydroxyl groups bonded in the molecule include hydrogenated biphenol, dicyclohexanolmethane, bis (dimethylcyclohexanol) methane, 1,
2-bis (cyclohexanol) ethane, 1,3-bis (cyclohexanol) propane, 1,4-bis (cyclohexanol) butane, 1,5-bis (cyclohexanol) pentane, 1,6-bis (cyclohexanol) ) Hexane, 2,2-bis (cyclohexanol) propane, bis (cyclohexanol) phenylmethane,
α, α-bis (4-hydroxycyclohexyl) -4-
(4-hydroxy-α, α-dimethylcyclohexyl)
-Ethylbenzene, 3,3-bis (cyclohexanol) pentane, 5,5-bis (cyclohexanol) heptane, dodecahydrofluorangeol, tris (cyclohexanol) methane, tris (cyclohexanol) ethane, 1,3,3 -Tris (cyclohexanol) butane, tetrakis (cyclohexanol) ethane, 2,2-bis [4,4'-bis (cyclohexanol) cyclohexyl] propane, hydrogenated bisphenol C (C: cyclohexane), hydrogenated polyphenol, and the like. These mixtures are mentioned.

As the epoxidizing agent which can be used for the epoxidation of the double bond of the alicyclic olefin compound, it is preferable to use an aliphatic percarboxylic acid which does not substantially contain water. This is because when the epoxidation reaction is carried out in the presence of water, the ring-opening reaction of the epoxy group proceeds and the yield of the epoxy compound decreases. Therefore, the aliphatic percarboxylic acid is substantially free of water, and specifically, the water content in the aliphatic percarboxylic acid is 0.8% by weight or less, preferably 0.6% by weight. % Or less. The substantially water-free aliphatic percarboxylic acid referred to in the present invention is peracetic acid or the like produced by air oxidation of acetaldehyde or the like. For example, peracetic acid is disclosed in German Patent Laid-Open No. 1418465 or JP It is produced by the method described in Japanese Patent Publication No. 54-3006. According to this method, as compared with the case of synthesizing an aliphatic percarboxylic acid from hydrogen peroxide and extracting it with a solvent to produce an aliphatic percarboxylic acid, a large amount of the aliphatic percarboxylic acid is continuously and continuously concentrated. Can be obtained at a substantially low cost.

As the aliphatic percarboxylic acids, formic acid, peracetic acid, perisobutyric acid, pertrifluoroacetic acid and the like can be used. Of these, peracetic acid is a preferable epoxidizing agent because it is industrially available at low cost and has high stability.
There is no strict limitation on the amount of the aliphatic percarboxylic acid that is an epoxidizing agent, and the optimum amount in each case is an individual epoxidizing agent to be used, a desired epoxidation degree, an individual epoxidation target to be used, etc. It depends on variable factors such as. It is preferable to add an ordinary epoxidizing agent in an equimolar amount or more with respect to the olefin group. However, it is usually disadvantageous in excess of 2 times the molar amount in view of economical efficiency and the side reaction described below, and in the case of peracetic acid, the 1-1.5 times molar amount is preferable.

The epoxidation reaction is carried out by adjusting the presence or absence of an inert solvent and the reaction temperature according to the physical properties of the equipment and raw materials.
The inert solvent can be used for the purpose of reducing the viscosity of the raw material and stabilizing it by diluting the epoxidizing agent. In the case of peracetic acid, aromatic compounds, esters and the like can be used. Particularly preferred solvents are hexane, cyclohexane, toluene, ethyl acetate and methyl acetate.

The reaction temperature range that can be used depends on the reactivity of the epoxidizing agent used. Generally, 0 ° C or higher, 1
It is not higher than 00 ° C. With respect to peracetic acid, which is a preferable epoxidizing agent, 20 to 70 ° C. is preferable. The reaction is slow at 20 ° C or lower, and the decomposition of peracetic acid occurs at 70 ° C. The charged molar ratio of the epoxidizing agent to the unsaturated bond can be changed according to the purpose such as the amount of the unsaturated bond to be left. No special manipulation of the reaction mixture is necessary, for example the mixture may be stirred for 1-5 hours. Isolation of the obtained epoxide can be carried out by a suitable method, for example, a method of precipitating with a poor solvent, a method of distilling off the solvent by adding the epoxide to hot water with stirring, or a direct desolvation method. it can.

The epoxy resin obtained as described above is
It is an alicyclic epoxy and contains 100 to 20% by weight of an epoxy resin containing no ester bond.

(Compound having an alicyclic epoxy group in the molecule and having an ester bond and / or epoxy compound having a glycidyl group (B)) Having an alicyclic epoxy group in the molecule and an ester As the compound having a bond and / or the epoxy compound (B) having a glycidyl group, a compound having at least one alicyclic epoxy group in the molecule, preferably 1 to 2 is used without particular limitation. You can

Specific examples include di (3,4-epoxycyclohexyl) adipate, (3,4-epoxycyclohexyl) methyl-3,4-epoxycyclohexanecarboxylate, (3,4-epoxy-6-methylcyclohexyl). Examples thereof include methyl-3,4-epoxy-6-methylcyclohexanecarboxylate and ethylene-1,2-di (3,4-epoxycyclohexanecarboxylic acid) ester. These compounds can be used alone or in combination of two or more kinds.

Of the compounds having an alicyclic epoxy group in the molecule described above, particularly preferable compounds are 3,4-
Examples thereof include epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxycyclohexylmethyl alcohol, 3,4-epoxycyclohexylethyltrimethoxysilane, and compounds represented by the following formula.

[0023]

[Chemical 4]

In the present invention, a compound having an oxetane ring in the molecule can also be used. The compound having an oxetane ring used in the coating composition of the present invention has the following oxetane ring capable of undergoing ring-opening polymerization by irradiation of ultraviolet rays in the presence of a cationic polymerization initiator.

[0025]

[Chemical 5]

A compound having at least 1, preferably 1 to 15, and more preferably 1 to 4 in one molecule (hereinafter referred to as oxetane compound OXE), and specifically, for example, the following formula ( The compounds represented by 4) and the compounds represented by the following formulas (10), (11) and (12) are included.

[0027]

[Chemical 6]

In the above formula (4), R⁶Is a hydrogen atom,
Fluorine atom, straight or branched chain having 1 to 6 carbon atoms
Or cyclic alkyl groups (eg, methyl, ethyl, n-
Or i-propyl, n-, i- or t-butyl
, Pentyl, hexyl, cyclohexyl, etc.), charcoal
Linear or branched fluoroal having 1 to 6 elementary atoms
Kill group (eg, monofluoromethyl, difluoromethyl
, Trifluoromethyl, 2,2,2-trifluoroe
Chill, perfluoroethyl, perfluoropropyl, para
-Fluorobutyl, perfluorohexyl groups, etc.)
Ryl group, aryl group (eg, phenyl, naphthyl,
Ryl, xylyl group, etc.), aralkyl group (eg benzene
Dil, phenethyl group, etc.), furyl group or thienyl group
Representation; R ⁷Has a valence corresponding to the value of p and hydrogen
Represents an atom or a monovalent to tetravalent organic group; Z is an oxygen atom or
Represents a sulfur atom; p is an integer of 1 to 4.

The monovalent to tetravalent organic group which R ⁷ can represent is the number of carbon atoms which may contain at least one hetero atom selected from O, S, N and F and / or a siloxane bond. 1 to 30 linear, branched or cyclic monovalent to tetravalent hydrocarbon groups can be mentioned.

More specifically, the monovalent group represented by R ⁷ is, for example, a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms (eg, methyl, ethyl, n-). Or i-propyl, n-, i- or t
-Butyl, pentyl, hexyl, cyclohexyl group, etc.), a linear or branched alkoxyalkyl group having 1 to 6 carbon atoms (eg, methoxyethyl, ethoxyethyl, butoxyethyl, ethoxymethyl group, etc.), 1 carbon atom 6 straight-chain or branched-chain fluoroalkyl groups (for example, monofluoromethyl, difluoromethyl, trifluoromethyl, 2,2,2-trifluoroethyl, perfluoroethyl, perfluoropropyl, perfluorobutyl, perfluoromethyl) Fluorohexyl group, etc.), allyl group, aryl group (eg phenyl, naphthyl, tolyl, xylyl group etc.), aralkyl group (eg benzyl, phenethyl group etc.), furyl group, thienyl group, epoxy-containing group (eg glycidyl) 3,4-epoxycyclohexylmethyl And the like), and the like.

The divalent group represented by R ⁷ is, for example, a linear, branched or cyclic alkylene group (particularly methylene, ethylene, 1,2- or 1,3-propylene, butylene). , An alkylene group having 1 to 15 carbon atoms such as a cyclohexylene group), a poly (alkyleneoxy) group having 4 to 30 carbon atoms, preferably 4 to 8 carbon atoms (for example, poly (ethyleneoxy), poly (propyleneoxy)). Group), a phenylene group, a xylylene group, the following formulas (5) and (6),

[0032]

[Chemical 7]

(In the formula, R ⁸ is O, S, CH ₂ , NH, S
Represents O, SO ₂ , C (CF ₃ ) ₂ or C (CH ₃ ) ₂ )

[0034]

[Chemical 8]

(Wherein R ⁹ represents an alkylene group having 1 to 6 carbon atoms, an arylene group or a direct bond), or a carbon in which an alkylene group and an alkylene group are bonded by a (poly) siloxane chain. 2 to 30 atoms, preferably 2
6 groups (for example, the alkylene group is an ethylene or propylene group, and the (poly) siloxane chain has a molecular weight of 13
0 to 15,000, particularly 130 to 500, preferably those represented by the following formula (7)) and the like can be mentioned.

[0036]

[Chemical 9]

(In the formula, k represents an integer of 1 to 6, and l is 2 or 3.)

Further, examples of the trivalent or tetravalent group represented by R ⁷ include groups represented by the following formulas (8) to (11).

[0039]

[Chemical 10]

(In the formula, R ¹⁰ represents an alkyl group having 1 to 6 carbon atoms, for example, ethyl group)

[0041]

[Chemical 11]

(In the formula, four R ¹¹ are the same or different and each represents an alkylene group having 1 to 6 carbon atoms, for example, an ethylene group.)

[0043]

[Chemical 12]

(In the formula, two R ^{12 s} are the same or different and each represents a hydrogen atom, a fluorine atom, an alkyl group having 1 to 6 carbon atoms, a fluoroalkyl group having 1 to 6 carbon atoms, an allyl group or an aryl group. Represents a furyl group or a thienyl group)

Of the monovalent to tetravalent organic groups which can be represented by R ⁷ ,
A monovalent or divalent group is preferable (that is, p is preferably 1 or 2), and among them, an alkyl group having 1 to 6 carbon atoms such as methyl, ethyl, propyl, butyl, and hexyl; an allyl group Glycidyl group; vinyl group; alkoxyalkyl group having 1 to 6 carbon atoms such as ethoxyethyl and methoxyethyl; benzyl group; 1 to 1 carbon atoms such as methylene, ethylene, propylene, butylene and hexylene
Preferred are alkylene groups of 6; p-xylylene group; groups represented by the following formula.

[0046]

[Chemical 13]

In the above formula (4), R ⁶ is preferably a hydrogen atom; an alkyl group having 1 to 6 carbon atoms such as methyl, ethyl, propyl, butyl or hexyl; and an allyl group. A hydrogen atom, a methyl group and an ethyl group are preferred.

Of the compound (OXE) having at least one oxetane ring in the molecule, (OXE-1): a compound having at least one oxetane ring and at least one hydroxyl group in the molecule, and preferably one each. OXE
-2): A compound having at least two oxetane rings or an oxetane ring in the molecule is suitable.

As the oxetane compound (OXE-1)
For example, p is 1 and R ⁷Is a hydrogen atom
In the case of the compound of the above formula (4), especially the following formula (4-1)
Mention may be made of the compounds shown.

[0050]

[Chemical 14]

(In the formula, R ⁶¹ is a hydrogen atom, a fluorine atom,
It represents a linear or branched alkyl group having 1 to 6 carbon atoms, a linear or branched fluoroalkyl group having 1 to 6 carbon atoms, or an allyl group. )

A typical example of the compound represented by the above formula (4-1) is the compound represented by the formula (4-1) when R ⁴ is an ethyl group.
Compounds of

Further, the above-mentioned oxetane compound (OXE-
Among 2), examples of the compound having at least two oxetane rings in the molecule (hereinafter referred to as polyoxetane compound) include the compound of the above formula (4) when p is an integer of 2 to 4, and among them, A compound represented by the following formula (4-2) is preferable.

[0054]

[Chemical 15]

(Wherein R ⁶¹ has the same meaning as described above and R ^61
71 represents a divalent to tetravalent organic group defined for R ⁷ in formula (4), and q represents an integer of 2 to 4. )

As a typical example of the compound represented by the above formula (4-2), R ⁶¹ is an ethyl group and R ⁷¹ is 1,4-
A tetramethylene group, a dodecamethylene group, an o-, m- or p-xylylene group, a group of the formula (6) in which R ⁹ is an ethylene group or a group of the formula (4-
The compound of 2) can be mentioned.

As the polyoxetane compound, in addition to the compound represented by the above formula (4-2), the following formula (1
Examples thereof include compounds represented by 2), (13) and (14).

[0058]

[Chemical 16]

(In the formula, two R ^{61 s} are the same or different and have the same meanings as described above, and an ethyl group is particularly preferable.)

[0060]

[Chemical 17]

(In the formula, s represents an integer of 25 to 200.)

Further, the oxetane compound (OXE-
Among 2), the compound having an oxetane ring in the molecule and an epoxy group (hereinafter referred to as an epoxy-containing oxetane compound) has one oxetane ring and one epoxy group in the molecule, and preferably has a molecular weight of 1,000. And a compound of the following formula (15)
The compound shown by can be mentioned.

[0063]

[Chemical 18]

(In the formula, R ¹³ represents an epoxy group-containing group, and R ⁶¹ has the same meaning as described above.)

Further, as a typical example of the epoxy-containing oxetane compound, a compound in the case where R ⁶¹ is an ethyl group and R ¹³ is a glycidyl group or a 3,4-epoxycyclohexylmethyl group in the above formula (15) is used. Can be mentioned.

The oxetane compound (OXE) described above
Can be used alone or in combination of two or more. In particular,
It is preferred to use the compound (OXE-1) and the compound (OXE-2) in combination. When used in combination, the amount of each of the oxetane compounds (OXE-1) and (OXE-2) used is 100 parts by weight of the total amount of the epoxy compound (A) and the epoxy compound (B), and the oxetane compound (OXE-1). 1 to 75 parts by weight, preferably 3 to 50 parts by weight, and an oxetane compound (OXE-1).
-2) can be in the range of 1 to 75 parts by weight, preferably 3 to 50 parts by weight.

(Copolymer (C) having at least one glycidyl group and / or alicyclic epoxy group in the molecule)
Copolymer (C) used in the coating composition of the present invention
Is a copolymer having at least one glycidyl group and / or at least one alicyclic epoxy group in the molecule.

As the epoxy group-containing monomer used as a raw material of the copolymer, any polymerizable unsaturated monomer containing an epoxy group can be used without particular limitation. Typical examples are glycidyl acrylate and glycidyl. Methacrylate, methyl glycidyl acrylate, methyl glycidyl methacrylate, allyl glycidyl ether, vinyl glycidyl ether, etc. can be mentioned. Of these, glycidyl acrylate and glycidyl methacrylate are preferably used.

The alicyclic epoxy group-containing monomer used as the raw material of the copolymer is Cyclomer A200, M100.
(Manufactured by Daicel Chemical Industries, Ltd.) and the like are exemplified.

The other monomer copolymerizable with the above-mentioned epoxy group-containing monomer is a monomer which is appropriately used according to the intended performance of the resulting copolymer (C), and is, for example, methyl. Acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-, i- or t-butyl acrylate, n-, i
-Or t-butyl methacrylate, hexyl acrylate, hexyl methacrylate, octyl acrylate, octyl methacrylate, lauryl acrylate, lauryl methacrylate, stearyl acrylate, stearyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, etc. 24 alkyl or cycloalkyl ester; acrylic acid or methacrylic acid such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate C1 to C8 hydroxyalkyl ester; acryl Α, β-ethylenically unsaturated carboxylic acids such as acid, methacrylic acid, maleic acid, itaconic acid, crotonic acid; acrylamide, methacrylamide, N-methylacrylamide, N-ethylmethacrylamide, diacetoneacrylamide, N-methylolacrylamide , N-methylol methacrylamide, N-
Acrylamide or methacrylamide such as methoxymethyl acrylamide or N-butoxymethyl acrylamide or a derivative thereof; aromatic vinyl monomer such as styrene, vinyltoluene or α-methylstyrene; vinyl propionate, vinyl acetate, acrylonitrile, methacrylonitrile. , Vinyl pivalate, Veova monomer (manufactured by Shell Chemical Co., vinyl ester of branched fatty acid), silaplane FM0711, FM0721, FM0
Other vinyl monomers such as 725 (all of which are manufactured by Chisso Co., polydimethylsiloxane macromonomer having a methacryloyl group at the end) can be used.

The copolymer (C) comprises a monomer component composed of the above-mentioned epoxy group-containing monomer and, if necessary, another monomer, for example, in the presence or absence of a radical polymerization initiator, solution polymerization, bulk polymerization, It can be obtained by polymerization by a polymerization method known per se such as emulsion polymerization and suspension polymerization. The copolymer (C) has a number average molecular weight of 1,
000-100,000, and further 2,000-50,0
It is preferably within the range of 00.

The mixing ratio of each monomer component in the polymerization of the copolymer (C) is preferably within the following range with respect to 100 parts by weight of the total amount of the monomer components.

Epoxy group-containing monomer: 10 to 95 parts by weight, preferably 20 to 80 parts by weight. Other monomer: 0
85 parts by weight, preferably 10 to 70 parts by weight.

In the copolymer (C), the concentration of epoxy groups is 0.1 to 7.0 equivalents / kg, more preferably 0.2 to 5.0.
It is preferably within the range of equivalent weight / kg.

In the polymerization of the copolymer (C), a polydimethylsiloxane macromonomer such as Silaprene FM0721 (manufactured by Chisso Corporation) is used as another monomer, whereby the leveling property of the coating film obtained and the retort treatment are performed. It is possible to improve the lubricity of the coating film afterwards.

(Cationic Polymerization Initiator (D)) The cationic polymerization initiator (D) used in the present invention is a compound which generates a cation by ultraviolet irradiation to initiate polymerization, and for example, has the following formula (I). To (XV) represented by hexafluoroantimonate salt, pentafluorohydroxyantimonate salt, hexafluorophosphate salt, hexafluoroalzenate salt and other cationic polymerization initiators.

Ar₂I⁺・ X^-  (I) (In the formula, Ar represents an aryl group, for example, a phenyl group.
Then X^-Is PF₆ ^-, SbF₆ ^-Or AsF₆ ^-Represents), Ar₃S⁺・ X^-  (II) (In the formula, Ar and X^-Has the same meaning as above),

[0078]

[Chemical 19]

(In the formula, R ²⁰ represents an alkyl group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms, and r is 0.
Represents an integer of 3 and X ⁻ has the same meaning as above),

[0080]

[Chemical 20]

(In the formula, Y ⁻ is PF ₆ ⁻ , SbF ₆ ⁻ , AsF ₆
^- or SbF ₅ (OH) ^- represents a)

[0082]

[Chemical 21]

(Wherein X ^- has the same meaning as above)

[0084]

[Chemical formula 22]

(Wherein X ^- has the same meaning as above)

[0086]

[Chemical formula 23]

(Wherein X ^- has the same meaning as above)

[0088]

[Chemical formula 24]

(In the formula, R ²¹ represents an aralkyl group having 7 to 15 carbon atoms or an alkenyl group having 3 to 9 carbon atoms, and R ²² represents a hydrocarbon group having 1 to 7 carbon atoms or a hydroxyphenyl group. R ²³ represents an alkyl group having 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, and X ⁻ has the above meaning),

[0090]

[Chemical 25]

(In the formula, R ²⁴ and R ²⁵ each independently represent an alkyl group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms),

[0092]

[Chemical formula 26]

(Wherein R ²⁴ and R ²⁵ have the same meaning as above),

[0094]

[Chemical 27]

As the cationic polymerization initiator (D), a commercially available product may be used. Examples of commercially available products include UV.
ACURE1591 (manufactured by UCB, USA) CD-101
0, CD-1011, CD-1012 (manufactured by US Sartomer Company), Irgacure 264 (manufactured by Ciba Geigy Company),
CIT-1682 (manufactured by Nippon Soda Co., Ltd.) and the like can be mentioned.

Among the above-mentioned cationic polymerization initiators, a compound having a hexafluorophosphate anion (PF ₆ ⁻ ) is preferable from the viewpoints of toxicity, versatility and the like.

In the coating composition of the present invention, in addition to the above essential components (A), (B), (C) and (D), a lubricity imparting agent; a sensitizer; Pigments such as coloring pigments and extender pigments and dyes that do not significantly inhibit curing; modified resins such as polyol resins, phenol resins, acrylic resins, polyester resins, polyolefin resins, epoxy resins, epoxidized polybutadiene resins; organic resin fine particles A solvent or the like may be added.

The lubricity-imparting agent is added for the purpose of improving the lubricity of the resulting coating film.
Waxes such as fatty acid ester wax, which is an esterified product of a polyol compound and a fatty acid, a silicone wax, a fluorine wax, a polyolefin wax, an animal wax, a plant wax and the like can be mentioned.

Examples of the polyol compound as a raw material of the above fatty acid ester wax include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,3- or 1,4-butanediol, neopentyl glycol and 1,6-hexane. Mention may be made of diol, glycerin, di- or higher polyglycerin, trimethylolpropane, pentaerythritol, dipentaerythritol and the like. Among these, a polyol compound having 3 or more hydroxyl groups in one molecule is preferable, and among them, polyglycerin, trimethylolpropane, and pentaerythritol are preferable.

Examples of the fatty acid serving as the other raw material of the above fatty acid ester wax include saturated and unsaturated fatty acids, and fatty acids having 6 to 32 carbon atoms are preferable. Specific examples of suitable fatty acids include caprylic acid, pelargonic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid,
Saturated fatty acids such as behenic acid, serotic acid, montanic acid, melissic acid; caproleic acid, undecylenic acid, palmitoleic acid, oleic acid, linoleic acid, linolenic acid, eleostearic acid, cetrainic acid, erucic acid, licanoic acid, ricinoleic acid And unsaturated fatty acids such as arachidonic acid.

The fatty acid ester wax is preferably one in which at least 1/3 of the number of hydroxyl groups of the above polyol compound is esterified with a fatty acid.

Examples of silicone waxes include B
YK-300, BYK-320, BYK-330 [above, BYK Chemie (Big Chemie)], Silwet L-77, Silwet L-720, Silwet L-7602 [above, Nippon Unicar Co., Ltd.], Painted 29, Painted 32, Painted M
[Above, Dow Corning], Shin-Etsu Silicone KF-
96 [manufactured by Shin-Etsu Chemical Co., Ltd.] and the like, and examples of the fluorine-based wax include Shamrock wax SST.
-1 MG, Shamrock Wax SST-3, Shamrock Wax Fluoro Slip 231 [above, Shamrock Chemicals], POLYFLUO (Polyfluor) 120, 150, 400 [Micro Powders] and the like.

Examples of the polyolefin wax include Shamrock wax S-394, Shamrock wax S-395 [above, Shamrock Chemicals], Hoechst wax PE-520, Hoechst wax PE-521 [above, Hoechst company. ], Mitsui High Wax [manufactured by Mitsui Chemicals, Inc.] and the like. Further, animal waxes include, for example, lanolin, beeswax, and the like, and plant waxes include, for example, carnauba wax and beeswax. Etc.

The lubricity-imparting agents as described above can be used alone or in combination of two or more kinds. The compounding amount of the lubricity-imparting agent is (A) a compound having an alicyclic epoxy group in the molecule and no ester bond, and (B) a compound having an alicyclic epoxy group in the molecule and an ester bond. With respect to 100 parts by weight of the total amount of the compound or the epoxy compound having a glycidyl group, usually 10 parts by weight or less, preferably 0.1 to 5 parts by weight, more preferably 0.5 to 3 parts by weight. can do.

Among the above-mentioned lubricity imparting agents, the silicone wax is excellent in lubricity imparting property after coating curing and before retort treatment, and the fatty acid ester wax is superior in lubricity imparting property after coating curing and retort treatment. ing.
Therefore, it is preferable to blend at least one selected from silicone wax and fatty acid ester wax. In particular, when 0.01 to 5 parts by weight of a silicone wax and 0.1 to 5 parts by weight of a fatty acid ester wax are used in combination with respect to 100 parts by weight of the total amount of the epoxy compound (A) and the oxetane compound (B), It is possible to obtain a coating film having excellent lubricity-providing properties before and after the retort treatment.

The sensitizer is added for the purpose of further improving the curability by ultraviolet rays, and examples thereof include pyrene, perylene, acridine orange, thioxanthone, 2-chlorothioxanthone and benzoflavin. . The compounding amount of this sensitizer is such that the total amount of the epoxy compound (A) and the epoxy compound (B) is 100.
It is usually used in an amount of 10 parts by weight or less, preferably 3 parts by weight or less, based on parts by weight.

When a modified resin is blended, the modified resin includes a compound (A) having an alicyclic epoxy group in the molecule and no ester bond, and an alicyclic compound in the molecule. A compound having an epoxy group and an ester bond, and / or
Alternatively, it is preferably used in an amount of usually 0.1 to 50 parts by weight, particularly 5 to 20 parts by weight, based on 100 parts by weight of the total amount of the epoxy compound (B) having a glycidyl group.
As the modifying resin, epoxidized polybutadiene resin is particularly effective for improving the workability and adhesion of the coating film.

The organic resin fine particles have a particle size of 5
Organic resin fine particles in the range of 0 to 500 nm are preferable,
For example, acrylic resin fine particles whose inside is three-dimensionally crosslinked can be used. As the organic resin fine particles, those obtained by pulverizing an organic polymer into fine particles; those obtained by drying and pulverizing fine polymer particles obtained by emulsion polymerization in water in the presence of an emulsifier; organic in the presence of a polymer stabilizer Examples include polymer fine particles obtained by dispersion polymerization in a solvent, which are dried and pulverized. By blending organic resin fine particles into the coating composition of the present invention, the adhesion and processability of the coating film can be improved. When the organic resin fine particles are blended, the amount of the organic resin fine particles is usually 0.1 to 50 parts by weight based on 100 parts by weight of the total amount of the epoxy compound (A) and the epoxy compound (B).
In particular, it is preferably within the range of 1 to 10 parts by weight.

(Coating Composition) The coating composition of the present invention can be prepared by mixing the above-mentioned components and stirring so as to obtain a uniform coating composition. For example, mix each component, and heat as needed (eg 50 ℃).
It can be prepared by stirring for about 10 minutes until it becomes uniform with a stirrer such as a dissolver.

At that time, the compound (A) having an alicyclic epoxy group in the molecule and not having an ester bond, and the compound having an alicyclic epoxy group in the molecule and having an ester bond, and / or Glycidyl group-containing epoxy compound (B), copolymer (C) and cationic polymerization initiator (D)
The use ratio of can be as follows.

That is, the compound (A) having an alicyclic epoxy group in the molecule and not having an ester bond, and the compound having an alicyclic epoxy group in the molecule and having an ester bond and / or glycidyl The epoxy compound (B) having a group has a compound (A) content of 10 to 90 parts by weight, preferably 20 to 70 parts by weight, and more preferably 30 to 60 parts by weight, in such a proportion that the total amount of both is 100 parts by weight. The compound (B) can be used in the range of 10 to 90 parts by weight, preferably 30 to 80 parts by weight, more preferably 40 to 70 parts by weight. Total amount of both 10
In 0 parts by weight, the amount of the epoxy compound (A) is 10
If it is less than 1 part by weight, the hardness and adhesion of the resulting coating film will be poor. On the other hand, if the amount of the epoxy compound (A) is more than 90 parts by weight, the curability and retort resistance of the coating film by low irradiation of ultraviolet rays will be low. Inferior in nature.

The amount of the copolymer (C) used is the compound (A) having an alicyclic epoxy group in the molecule and not having an ester bond, and the compound having an alicyclic epoxy group in the molecule and an ester. 1 to 50 parts by weight, preferably 3 to 30 parts by weight, based on 100 parts by weight of the total amount of the compound having a bond and / or the epoxy compound (B) having a glycidyl group,
More preferably, it can be in the range of 5 to 20 parts by weight. When the amount of the copolymer (C) is less than 1 part by weight, the hardness of the coating film in water after post-heating during ultraviolet irradiation at a low irradiation amount,
When the amount of the copolymer (C) exceeds 50 parts by weight, on the other hand, the curability due to ultraviolet irradiation at a low irradiation amount is poor, and the coating film hardness decreases. , The retort resistance is reduced.

The amount of the cationic polymerization initiator (D) used is such that the compound (A) has an alicyclic epoxy group in the molecule and does not have an ester bond, and the alicyclic epoxy group is in the molecule. And / or a compound having an ester bond,
Total amount of epoxy compound (B) having glycidyl group 1
The amount can be usually 0.01 to 20 parts by weight, preferably 0.1 to 10 parts by weight, and more preferably 1 to 5 parts by weight with respect to 00 parts by weight.

The ultraviolet-curable can coating composition of the present invention comprises:
Has UV curability, tinplate, aluminum, tin-free steel, iron, zinc, copper, galvanized steel sheet,
Metal plates that are formed into metal cans such as alloy-plated steel plates of zinc and other metals (this metal plate may be subjected to chemical conversion treatment such as zinc phosphate treatment or chromate treatment); these metal plates Polyester resin such as polyethylene terephthalate, polyolefin resin such as polyethylene and polypropylene, polyamide resin, epoxy resin,
A cured coating film can be formed by applying a resin film-laminated metal plate obtained by laminating a resin film such as polyvinyl chloride; or a metal can obtained by molding these metal plates and irradiating with ultraviolet rays. The coating film thickness can be appropriately selected depending on the application, but it is usually within a range of about 2 to 20 μm, preferably about 2 to 8 μm as a dry coating film thickness.

The ultraviolet-curable can coating composition of the present invention comprises:
For example, roll coat painting, spray painting, brush painting,
It can be applied by a coating method such as bar coating, roller coating or silk screen printing. When the coating film contains a solvent, after coating, after removing the solvent by heating, the coating film is cured by ultraviolet irradiation,
Irradiation conditions can be appropriately changed according to the type and thickness of the applied coating composition. The wavelength of the ultraviolet rays to be irradiated is usually appropriate within the range of 200 to 600 nm, and an irradiation source having a highly sensitive wavelength can be appropriately selected and used according to the kind of the cationic polymerization initiator. .

Examples of the ultraviolet ray irradiation source include a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a xenon lamp, a carbon arc, a metal halide lamp, and sunlight. The irradiation conditions for the coating film are usually 10
~ 1,000 mJ / cm ² , especially 50-500 mJ / c
A range of m ² is suitable.

The coating film may be heated, if necessary, after the irradiation of ultraviolet rays. By heating, the unreacted substances in the coating film can be reduced, and the curability of the coating film by ultraviolet irradiation and the distortion of the coating film generated by molding can be relaxed. In some cases, this heating can improve the hardness and adhesion of the coating film. The heating is usually 150 to 25
It can be carried out under the condition of an ambient temperature of 0 ° C. for 1 to 30 minutes.

The ultraviolet-curable can coating composition of the present invention comprises:
Compound (A) having an alicyclic epoxy group in the molecule and not having an ester bond, and a compound having an alicyclic epoxy group in the molecule and having an ester bond and / or an epoxy compound having a glycidyl group (B) and the copolymer (C) are contained as a film-forming resin component, and in the presence of the cationic polymerization initiator (D), a low irradiation dose without requiring equipment such as nitrogen encapsulation. It can be efficiently cured by cationic polymerization even by UV irradiation of, and even in a thin film, it has excellent coating properties such as processability, adhesion, hardness, and scratch resistance, which are required as a can coating. It is possible to form a coating film having excellent appearance and resistance to retort. Therefore, the coating composition of the present invention is particularly suitable as a coating for the outer surface of a can.

[0119]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited thereto. In addition, "part" and "%" are based on weight.

(Production of Peracetic Acid Solution) Reference Production Example 1 114 k of a 10% acetaldehyde-ethyl acetate solution containing cobalt acetate was put in a 300 ml stainless reactor equipped with an air blowing port, a gas dispersion perforated plate and a cooling jacket.
Compressed air was blown in while charging at g / h, and the reaction was carried out at 45 ° C. The reaction solution contained 10.1% peracetic acid, 2.2% acetaldehyde monoperacetate, and 2.0% acetic acid. This solution was charged together with sodium polyphosphate into a distillation column and concentrated to obtain a peracetic acid solution. This peracetic acid solution had a peracetic acid concentration of 29.1% and a water content of 0.47%.

(Production of Epoxy Compound (A)) Reference Production Example 2 36 g of water, 12.0 g of sodium hydrogensulfate and isopropylidene were placed in a 1 liter jacketed flask equipped with a stirrer, a cooling tube, a thermometer and a nitrogen introducing tube. 500 g of -4,4'-dicyclohexanol (manufactured by Aldrich) and 500 g of Solvesso 150 (manufactured by Exxon Chemical Co.) as a solvent were added to carry out dehydration reaction at 100 ° C. The reaction was terminated when water was no longer distilled. When the reaction liquid was analyzed by gas chromatography, it was found that the yield of 2,2-bis was 96%.
(3 ', 4'-cyclohexenyl) propane had been produced. The obtained reaction solution was washed with 500 ml of ion-exchanged water using a separatory funnel, and the organic layer was distilled under reduced pressure to give 2,2-bis (3 ', 4'-cyclohexenyl) as a colorless transparent liquid.
387.0 g of propane was obtained and its purity was 96.1%. 100 g of this 2,2-bis (3 ′, 4′-cyclohexenyl) propane and 300 g of ethyl acetate were charged in the same 1 liter jacketed flask as described above, and the temperature in the reaction system was changed while blowing nitrogen into the gas phase part. 30 ℃
Over about 2 hours, 307.2 g of substantially anhydrous ethyl acetate solution of peracetic acid obtained in Reference Preparation Example 1 was obtained.
(Peracetic acid concentration: 29.1%, water content 0.47%) was added dropwise. After the dropwise addition of peracetic acid, the reaction was completed by aging for 3 hours at 30 ° C. Further, the reaction completion liquid is washed with water at 30 ° C.
After removing low boiling point at ℃ / 20mmHg, epoxy compound (A
19.4) was obtained. The purity of 2,2-bis (3 ′, 4′-epoxycyclohexyl) propane in the epoxy compound (A1) was 93.4%. The properties of the obtained product are oxirane oxygen concentration 11.3%, viscosity 3,550.
cP (25 ° C.), δ4.5-5p from ¹ HNMR
The peak derived from the internal double bond near pm disappeared, and δ
It was confirmed that a proton peak derived from an epoxy group was generated in the vicinity of 2.9 to 3.1 ppm.

Reference Production Example 3 300 g of 4,4′-dicyclohexanol methane, 600 g of toluene and 3 g of paratoluenesulfonic acid were added to a 1 liter jacketed flask equipped with a stirrer, a cooling tube, a thermometer and a nitrogen introducing tube. A dehydration reaction was performed at 110 ° C.
The reaction was terminated when water was no longer distilled. When the reaction solution was analyzed by gas chromatography, it was 96%
Di (3,4-cyclohexenyl) methane was produced in a yield of The obtained reaction solution was heated to 500 with a separatory funnel.
After washing with ml of ion-exchanged water, the organic layer was distilled under reduced pressure to obtain 269 g of colorless transparent liquid di (3,4-cyclohexenyl) methane. 100 g of this di (3,4-cyclohexenyl) methane and 200 g of ethyl acetate were charged into a 1 liter jacketed flask similar to that in Reference Production Example 2, and the temperature in the reaction system was 25 ° C. while blowing nitrogen into the gas phase.
Over about 3 hours, 276.2 g of substantially anhydrous ethyl acetate solution of peracetic acid obtained in Reference Preparation Example 1
(Peracetic acid concentration: 29.1%) was added dropwise. After the addition of peracetic acid was completed, the reaction was completed by aging for 4 hours at 30 ° C. 3 more
The reaction completed liquid was washed with water at 0 ° C., and deboiling was performed at 70 ° C./30 mmHg to obtain 106.4 g of an epoxidized product (A2). The purity of di (3,4-epoxycyclohexyl) methane in the epoxy compound (A2) was 91.8%.
The obtained product has the oxirane oxygen concentration of 13.8.
%, The viscosity was 2,590 cP (25 ° C.), the peak derived from the double bond in the vicinity of δ4.5 to 5 disappeared from ¹ HNMR, and the proton derived from the epoxy group appeared in the vicinity of δ2.9 to 3.3. Generation of a peak was confirmed.

Reference Production Example 4 The same procedure as in Reference Production Example 2 was repeated except that 400 g of hydrogenated bisphenol sulfone (that is, 4,4′-dicyclohexanol sulfone) and 500 g of Solvesso 150 (manufactured by Exxon Chemical Co.) were used as a solvent. 330 g of di (3,4-cyclohexenyl) sulphone are obtained, the purity of which is 92.
It was 2%. 100 g of this reaction product and 300 of ethyl acetate
was charged into a 1-liter jacketed flask similar to the above, and while blowing nitrogen into the gas phase, the temperature in the reaction system was adjusted to 40 ° C. over about 2 hours in an ethyl acetate solution of peracetic acid 242. 7 g (peracetic acid concentration: 29.1%) was added dropwise. After the addition of peracetic acid was completed, the reaction was completed by aging for 4 hours at 40 ° C. The crude liquid is washed with water at 30 ° C and 70 ° C / 3.
Epoxy compound (A3) 9 after deboiling at 0 mmHg
7.0 g was obtained. Di (3,3) in the epoxy compound (A3)
The purity of 4-epoxycyclohexyl) sulfone is 9
It was 0.3%. The properties of the obtained product were as follows: oxirane oxygen concentration 10.8%, viscosity 6,700 cP (25 ° C.), ¹ HNMR revealed that a peak derived from a double bond near δ4.5 to 5 disappeared, and δ2. It was confirmed that a proton peak derived from an epoxy group was generated in the vicinity of 9 to 3.3.

(Production of Copolymer (C) Having at least One Epoxy Group in the Molecule) Production Example 1 Toluene 500 was placed in a flask equipped with a stirrer and a condenser.
Parts were charged and heated to 95 ° C. with stirring. Then, while maintaining the same temperature, a mixture prepared by previously mixing and dissolving 150 parts of glycidyl methacrylate, 250 parts of n-butyl methacrylate and 50 parts of 2,2'-azobisisobutyronitrile was added dropwise thereto over 4 hours. After polymerization, toluene was removed by vacuum distillation to obtain a copolymer (C). The resulting copolymer (C) had a number average molecular weight of about 2500 and an oxirane oxygen concentration of 1.4%.

Production Examples 2 to 3 Various copolymers were obtained in the same manner as in Production Example 1 except that the composition of the mixture to be dropped was as shown in Table 1 below. The number average molecular weight, oxetane ring concentration and glycidyl group concentration of the obtained copolymer are shown in Table 1 below.
The amounts of each component in Table 1 are indicated by parts by weight.

[0126]

[Table 1]

1) GMA: glycidyl methacrylate 2) CYMA-200: epoxycyclohexylmethyl acrylate, trade name Cyclomer A-200 (manufactured by Daicel Chemical Industries, Ltd.) 3) n-BMA: n-butyl methacrylate 4) AIBN: 2,2'-azobisisobutyronitrile 5) HEMA: 2-hydroxyethyl methacrylate

Examples 1-7 and Comparative Examples 1-2 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (in Table 2, CEL
-2021P), 3-ethyl-3-hydroxymethyl oxetane (in Table 2, indicated as OXE), and a compound in which R ^{61 in} the formula (12) is an ethyl group (E in Table 2). -Indicated as DOA), the copolymer obtained in each production example, UVACURE1591 (UCB, USA)
Manufactured by ^K.K. , a cationic photopolymerization initiator having PF ^6- ), 1 mol of decaglycerin ether (having 12 hydroxyl groups in one molecule) which is polyglycerin having a polymerization degree of 10 and 10 mol of lauric acid are reacted. 1 part of fatty acid ester wax and 0.2 part of Paintad M (made by Dow Corning, silicone wax) are mixed and kept at 50 ° C. for 20
The mixture was stirred for 1 minute to obtain an ultraviolet-curable can coating composition.

[0129]

[Table 2]

1) E-DOA: Compound of Reference Production Example 2) E-DOA-f: Compound of Reference Production Example 3) CEL-2021P: 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxy Rate (manufactured by Daicel Chemical Co., Ltd.) 4) CEL-3000: 1,2,8,9-diepoxylimonene (manufactured by Daicel Chemical Co., Ltd.) 5) OXE: 3-ethyl-3-hydroxymethyloxetane ( 6) UVACURE-1591: sulfonium salt-based cation catalyst (manufactured by Daicel UCB Co., Ltd.)

Preparation of Test Coated Plate Each of the coating compositions obtained in the above Examples and Comparative Examples had a thickness of 0.
20μm tin free steel plate (TFS) and 0.20 mm thick tin free steel plate with a thickness of 12μ
m homo-PET (polyethylene terephthalate) sheet thermo-compression bonded to PET steel sheet, each having a dry film thickness of 5 μm
The high pressure mercury lamp (160
W / cm) was applied from a distance of 15 cm from the coated plate so that the energy dose was 80 mJ / cm ^2, and the coating film was cured to give a test coated plate. Each of the obtained test coated plates was tested based on the following test method. All tests were conducted at 20 ° C.

Test method Pencil hardness: JIS K-5400 was applied to the coating film of the test coated plate.
The pencil scratch test specified in 8.4.2 (1990) was performed. The evaluation was performed by the yabure method.

Impact resistance (DuPont type): JIS K-5
400 8.3.2 (1990) using a DuPont impact tester on the test coated plate from the opposite side of the coating surface, with a diameter of the hammer 3/8 inch, a falling weight load of 500 g, and a falling weight height of 30 cm. Impact processing was performed, the processed portion was observed with a microscope, and evaluated according to the following criteria. ⊚: Neither crack nor peeling of the coating film is observed. ◯: A slight crack is seen, but no peeling of the coating film is seen. Δ: Significant cracks are seen, but the coating film is not peeled off. X: Peeling of the coating film is seen.

Adhesion: JIS K-5400 8.5.
2 (1990) According to the cross-cut tape method, 100 squares of 1.5 mm × 1.5 mm were created on the coated plate surface of the test coated plate, and the adhesive cellophane tape was adhered to the surface, and after the tape was rapidly peeled off. The condition of the squares was evaluated according to the following criteria. A: No peeling is observed. ◯: The edges of the squares are slightly removed. Δ: Peeling is slightly observed in addition to the borders of the squares. X: Remarkable peeling is recognized.

Hardness in hot water: The test coated plate was heated at 200 ° C. for 1 minute, immersed in warm water at 80 ° C. for 10 minutes, and the pencil hardness was measured in the warm water at 80 ° C. Evaluation is JIS K-5
400 8.4.2 (1990).

Further, the leveling properties of the coating compositions obtained in the above Examples and Comparative Examples were tested according to the following method.

Leveling property: Each coating composition was coated on a PET steel sheet by a roll coating method (natural coating) so that the dry film thickness was 5 μm, and the condition from coating to ultraviolet irradiation was 0.5 seconds. The appearance of the coated surface when it was cured by irradiation with ultraviolet rays was visually evaluated. The evaluation was performed according to the following criteria. ⊚: Roll surface is not seen on the coated surface and the smoothness is excellent. ◯: The roll surface is slightly smooth, but the smoothness is good. Δ: Roll eyes are considerably seen on the coated surface, and smoothness is considerably inferior. X: Rolls are noticeable on the coated surface and the smoothness is remarkably inferior.

Test results The results of the above tests are shown in Table 3 below.

[0139]

[Table 3]

[0140]

[Table 4]

[0141]

The ultraviolet-curable coating composition for a can of the present invention can be cured by irradiation with ultraviolet rays at a low irradiation amount, and the cured product has good workability, adhesion, hardness, scratch resistance and the like. Excellent coating performance, especially coating appearance and retort resistance.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4J038 BA212 CB002 CC022 CF022                       CG032 CG072 CG142 CG162                       CG172 CH032 CH042 CH172                       CJ132 DB261 DL032 GA02                       GA07 GA12 GA13 JA20 JA55                       KA03 MA02 NA01 NA11 NA12                       NA14 PA17 PB04 PC02

Claims (6)

[Claims] 1. A compound (A) having 100 to 100 parts by weight of an alicyclic epoxy group in a molecule and not having an ester bond, and an alicyclic epoxy group in a molecule and having an ester bond. 0 to 90 parts by weight of an epoxy compound (B) having a compound and / or a glycidyl group, and a compound (A)
And at least 1 glycidyl group and / or alicyclic epoxy group in the molecule, relative to 100 parts by weight of the total of (B).
1 to 50 parts by weight of the copolymer (C), and a cationic polymerization initiator (D) that generates cations by ultraviolet irradiation.
An ultraviolet-curable coating composition for cans, which contains 0.01 to 20 parts by weight. 2. The compound (A) is an epoxy compound represented by the following general formula (I):
The ultraviolet-curable can coating composition described above. [Chemical 1] (In the formula, X is an oxygen atom, a sulfur atom, -SO-, -SO ² -,-
^{CH 2 -, - C (CH} 3) 2 -, - CBr 2 -, - C (CBr 3) 2 -,
Or ^{-C (CF 3) 2 -,} - C (CCl 3) 2 -, - CH (C 6 H 5) -
Is a divalent group or a mere single bond connecting two alicyclic groups, R ^{1 to} R ¹⁸ may be the same or different, and these are a hydrogen atom, a halogen atom, or an oxygen atom. Alternatively, it is a hydrocarbon group which may contain a halogen atom, or an alkoxy group which may have a substituent. ) 3. The copolymer (C) is a copolymer of a glycidyl group-containing polymerizable unsaturated monomer and / or an alicyclic epoxy group-containing polymerizable unsaturated monomer and another polymerizable unsaturated monomer. The ultraviolet-curable coating composition for cans according to claim 1. 4. A lubricity imparting agent is added in an amount of 0.01 to 1 with respect to 100 parts by weight of the total amount of the compounds (A) and (B).
The UV-curable can coating composition according to claim 1 or 2, wherein the UV-curable coating composition contains 0 part by weight. 5. The resin fine particles are further contained in an amount of 0.1 to 50 parts by weight based on 100 parts by weight of the total amount of the compounds (A) and (B). 2. The ultraviolet-curable can coating composition according to. 6. The ultraviolet-curable can coating composition according to any one of claims 1 to 5 is applied to a metal plate, a resin film-laminated metal plate or a metal can formed by molding these metal plates, and ultraviolet rays are applied. A method for producing a painted metal can, which comprises irradiating and curing.