JPH09143395A - Ultraviolet-curable resin composition and coating agent containing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a coating resin compsn. which forms a coating film excellent in adhesive properties, resistance to retorting, and hardness by compounding a free-radical-polymerizable (meth)acrylate compd., a non-free-radical- polymerizable compd., a vinyl ether compd., and a photochemical free-radical polymn. initiator. SOLUTION: This ultraviolet-curable resin compsn. is obtd. by compounding a free-radical-polymerizable acrylate and/or methacrylate compd. (A) (e.g. a reactive oligomer or reactive diluent monomer having at least one free-radical- polymerizable group such as CH2 =CHCOO- or CH2 =CCH3 COO-), a non-free- radical-polymerizable compd. (B) having a glass transition point of 40-150 deg.C and a number average mol.wt. of 500-5,000 in a wt. ratio to ingredient A of (5:95)-(60:40), at least one vinyl ether compd. (C) selected from among compds. represented by formulas (1) to (4) in a wt. ratio to the sum of ingredients A and B of (5:95)-(90:10), and a photochemical free-radical polymn. initiator (D) in an amt. of 1-20wt.% of the sum of ingredients A, B, and C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition which is cured by ultraviolet irradiation, and more particularly to an ultraviolet curable resin composition which is useful as a coating agent for metal cans and polyester film-coated drawn metal cans.

[0002]

2. Description of the Related Art Acrylic resins, unsaturated polyester resins, polyene-thiol resins, cation polymerization epoxy resins and the like, which are radical polymerization types, are known as ultraviolet curable resins. Among these resin compositions, radical polymerization type acrylic resins, cationic polymerization type epoxy resins and the like are used for coating agents, printing inks, adhesives and the like.

JP-A-7-111166 discloses an active energy ray-curable resin composition for paper using a pentaerythritol acrylate and a non-radical-polymerizable resin having a softening point of 30 ° C. or higher. Japanese Patent No. 157668 discloses a paper coating agent comprising a polymer of an unsaturated group-containing compound, a vinyl ether compound, and a photocationic polymerization initiator.

A metal can made of aluminum or steel or a drawn metal can coated with a polyester film (a polyester film-covered drawn metal can is formed by laminating a polyethylene terephthalate film on a metal plate made of aluminum or steel and drawing it into a cylindrical type having a capacity of 200 cc to 500 cc. After being coated with a coating agent, the neck-in processing for the lid winding part and the diamond cutting processing for the body of the can (the square pyramid-shaped irregularities are added) are applied. After being filled, the retort treatment (hot water treatment at 130 ° C. for 30 minutes) for sterilizing the contents is performed. Therefore,
Such coating materials are required to have various high suitability for them (adhesion of cured coating film, workability, retort resistance, etc.) and high-speed curing property. However, conventional acrylic resin is
Adhesiveness, processability, retort resistance is insufficient, in the case of an epoxy resin, the curing speed is slow, especially in a system containing a pigment, the curing speed is remarkably slow, and the active energy for paper described in the above publication. The wire-curable resin composition and the coating agent have insufficient adhesion to metal and workability, and are not satisfactory as a coating agent for metal cans and polyester film-coated drawn metal cans.

[0005]

The object of the present invention is to cure ultraviolet rays, which are useful as coating agents having excellent adhesion, processability, retort resistance, and coating hardness to metal cans and polyester film-coated drawn metal cans. A mold resin composition is provided.

[0006]

[Means for Solving the Problems] That is, the first invention is a radical-polymerizable acrylate and / or methacrylate compound (A), a non-radical-polymerizable compound (B),
A second invention is an ultraviolet-curable resin composition containing a vinyl ether compound (C) and a photoradical polymerization initiator (D), wherein the non-radical polymerizable compound (B) has a glass transition point of 40 ° C. or higher. The ultraviolet-curable resin composition according to the first invention, which is 150 ° C. or lower, and the third invention is that the non-radical-polymerizable compound (B) is a ketone formaldehyde resin. An ultraviolet curable resin composition according to any one of the inventions.

A fourth invention is the ultraviolet curing according to any one of the first to third inventions, wherein the vinyl ether compound (C) is one or more selected from the group of the following formulas (1) to (4). Type resin composition.

[0008]

Embedded image

A fifth aspect of the invention is the ultraviolet-curable resin composition according to any one of the first to fourth aspects of the invention, which contains a pigment (E).

Further, a sixth invention is a coating agent containing the ultraviolet curable resin composition according to any one of the first to fifth inventions, and the seventh invention is to coat a metal can. A sixth aspect of the invention is the coating agent according to the sixth aspect of the invention, and the eighth aspect of the invention is the coating agent according to the sixth aspect of the invention, which coats a polyester film-coated drawn metal can.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The radically polymerizable acrylate and / or methacrylate compound (A) used in the present invention is a radically polymerizable CH ₂ ═CHCO in the molecule.
Is a O- and CH ₂ = reactive with CCH ₃ COO- 1 or more oligomers and reactive diluent monomers. Examples of reactive oligomers include polyester (meth) acrylates obtained by reaction of saturated or unsaturated polycarboxylic acids with alkyl polyols and (meth) acrylic acid,
Epoxy poly (meth) acrylate obtained by reaction of epoxy resin and (meth) acrylic acid, urethane poly (meth) acrylate obtained by reaction of polyol, polyisocyanate and hydroxyl group-containing (meth) acrylate, polysiloxane and (meth ) Polysiloxane poly (meth) acrylate obtained by reaction with acrylic acid, polyamide poly (meth) acrylate obtained by reaction with polyamide (meth) acrylic acid, and the like. Among these, polyester (meth) acrylate and epoxy poly (meth) acrylate are particularly preferable as the coating agent for the metal can.

The reactive diluent monomer of the present invention includes 1
A functional substance, a bifunctional, a trifunctional, a tetrafunctional or higher can be appropriately selected, and a liquid substance having a viscosity at 25 ° C. of 500 cps or less is preferable. Among the reactive diluting monomers, monofunctional ones include alkyl (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate and propyl (meth) acrylate, and (meth) acrylates of alkylene oxide adducts of alkylphenols. , Cyclohexyl (meth) acrylate, benzyl (meth) acrylate and the like.

Among the reactive diluent monomers, bifunctional ones include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate and butylene glycol. Examples thereof include di (meth) acrylate, bisphenol A alkylene oxide di (meth) acrylate, and bisphenol F alkylene oxide di (meth) acrylate.

Among the reactive diluting monomers, further trifunctional ones include trimethylolethane tri (meth) acrylate, trimethylolpropane tri (meth) acrylate and glycerin tri (meth) acrylate.
Examples of tetrafunctional or higher functional groups include ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol alkylene oxide tetra (meth) acrylate, and dipentaerythritol hexa (meth) acrylate.

The non-radical-polymerizable compound (B) used in the present invention means a compound inactive to radical polymerization. Since it is inactive against radical polymerization, it can suppress and alleviate curing strain during radical polymerization and maintain and improve the adhesion of the coating film. Glass transition temperature of these non-radical polymerizable compounds (B) (hereinafter abbreviated as Tg)
Is preferably 40 ° C. or higher and 150 ° C. or lower. When the glass transition temperature is 40 ° C or lower, the heat resistance of the coating film is poor,
If the retort treatment causes blisters, or if the glass transition temperature is 150 ° C. or higher, the coating film becomes brittle and the workability tends to be poor.

The number average molecular weight (hereinafter abbreviated as Mn) of these non-radical polymerizable compounds (B) is preferably 500 or more and 5000 or less. If the number average molecular weight is 500 or less, the adhesion to metal cans and polyester film-coated drawn metal cans tends to be insufficient.
When it is 0 or more, the viscosity of the coating agent increases, and it may be difficult to coat the metal can or the like.

Specific examples of the non-radical polymerizable compound (B) used in the present invention include a ketone formaldehyde resin, a xylene formaldehyde resin, an epoxy resin, a polyester resin, a terpene resin and the like, and a ketone formaldehyde resin is preferable.

The ketone formaldehyde resin is synthesized by addition condensation of aromatic and / or aliphatic ketone and formaldehyde, and its hydrogenated form or isocyanate modified form can be used. For example, Synthetic resin AP manufactured by Huls
(Tg: 51 ° C., Mn: 780), Synthetic
resin SK (Tg: 83 ° C, Mn: 800), S
synthetic resin BL1201 (Tg:
124 ° C., Mn: 1800) and the like.

A xylene-formaldehyde resin synthesized by addition condensation of meta-xylene and formaldehyde and a derivative thereof modified with mesitylene, phenol or the like are also suitably used. For example, Nikanol Resin HP-120 (Tg: 76) manufactured by Mitsubishi Kasei Co., Ltd. 0.8 ° C, Mn: 13
00), Nikanol Resin HP-100 (Tg: 67.
5 ° C, Mn: 1200), Nikanol Resin GHP-1
60 (Tg: 114 ° C., Mn: 1500) and the like.

As the epoxy resin, bisphenol A
And / or a bisphenol type epoxy resin obtained by addition polymerization of bisphenol F and epichlorohydrin. Examples of the bisphenol A type include Epicoat 1004 (Tg: 53 ° C., manufactured by Yuka Shell Epoxy Co., Ltd.).
Mn: 1400), Epicoat 1007 (Tg: 69)
C, Mn: 2900), Epicoat 1009 (Tg: 7)
9 ° C., Mn: 3800), and as a bisphenol F type, Epicoat 4004P (Tg: 43 ° C., Mn: 16)
30), Epicor 4007P (Tg: 59 ° C., Mn: 3)
166), Epicoat 4009P (Tg: 62 ° C., M
n: 4100), Epicoat 4010P (Tg: 63)
C., Mn: 4640) and the like.

The polyester resin is preferably a linear saturated polyester obtained by a condensation reaction of a polybasic acid and a polyhydric alcohol. For example, Byron 220 (Tg: 53 ° C., Mn: 2000 to 3000) manufactured by Toyobo Co., Ltd. may be mentioned.

The terpene-based resin is a general term for resins made from turpentine oil obtained from raw pine resin, kraft pulp and pine chips, for example CL manufactured by Yasuhara Chemical Co.
EARON P-125 (Tg: 68 ° C., Mn: 70
0) and YS RESIN TO-125 (Tg: 64
C, Mn: 800).

In addition to the above, melamine formaldehyde resin, benzoguanamine formaldehyde resin, phenol formaldehyde resin, epoxy resin, terpene resin, rosin resin, acrylic resin, urethane resin and the like may be used alone or appropriately as long as they satisfy the condition of non-radical polymerizability. It can be used in combination.

The vinyl ether compound (C) used in the present invention has a vinyl ether group represented by CH ₂ ═CH—O—C, and the compound having such a functional group has cationic polymerizability and radical polymerization. It is also a compound having properties. Such vinyl ether compound (C)
Examples of the compound include various compounds. However, when a polyfunctional compound having two or more vinyl ether groups is used, curing strain may occur, resulting in poor adhesion. Therefore, it is preferable to use a monofunctional compound. It is preferable to have a Cl group, an OH group, a phenyl group or a glycidyl group from the viewpoint of excellent adhesion to a substrate, and a Cl group or a glycidyl group is most desirable from the viewpoint of adhesion to a polyester film.

Examples of such vinyl ether compound (B) include chloroethyl vinyl ether, chlorobutyl vinyl ether, chloroethoxyethyl vinyl ether,
Examples thereof include hydroxy-el vinyl ether, hydroxypropyl vinyl ether, hydroxybutyl vinyl ether, glycidyl vinyl ether, glycidyl ethyl vinyl ether and phenyl ethyl vinyl ether.

The photo-radical polymerization initiator (D) used in the present invention can be arbitrarily selected from known ones and used alone or in appropriate combination. Specific examples thereof include hydrogen abstraction type photopolymerization initiators such as benzophenone, methyl orthobenzoylbenzoate, diethylthioxanthone, and isopropylthioxanthone, benzoin ether, benzyldimethylketal, α-hydroxyalkylphenone, α-aminoalkylphenone, and acylphosphine. Examples thereof include intramolecular cleavage type photopolymerization initiators such as fin oxide.

The ultraviolet-curable resin composition of the present invention can be used as a clear top coat paint or a size coat paint on the outer surface of a metal can or a polyester film-coated drawn metal can without blending the pigment (E). Further, by blending the pigment (E), it can be used as a white coat paint. As the pigment (E), titanium oxide,
Examples thereof include barium sulfate, phthalocyanine blue, benzidine yellow, watching red and carbon black. When used as a white coat paint, titanium dioxide is preferable.

The mixing ratio of the radical-polymerizable acrylate and / or methacrylate compound (A) and the non-radical-polymerizable compound (B) is (A) / (B) = 95 / 5-40
/ 60 is preferable, and more preferably (A) / (B) = 8
0/20 to 60/40. When the amount of (B) is relatively large, the curability becomes poor, and conversely, when the amount of (B) is small, the heat resistance and workability tend to become poor. The mixing ratio of (A + B) and vinyl ether compound (C) is (A + B)
/ C = 95/5 to 10/90 is preferable, and (A + B) / C = 80/20 to 30/70 is more preferable.
If the amount of (C) is large, the curability, workability, and adhesion are poor, and conversely, if the amount of (C) is small, the viscosity of the ultraviolet curable resin composition is high, and the coatability tends to be poor. The photoradical polymerization initiator (D) is 1 to 100 parts by weight of the total amount of the radical-polymerizable acrylate and / or methacrylic compound (A), the non-radical-polymerizable compound (B) and the vinyl ether compound (C). It is preferable to add 20 parts.
When the pigment (E) is used, (A), (B), (C)
It is preferable to mix 10 to 120 parts by weight with respect to 100 parts by weight as the total weight.

If desired, a cationically polymerizable alicyclic epoxy compound can be used in the composition of the present invention in the range of 5 to 80% by weight. Specific examples of the alicyclic epoxy compound include “UVR-611” manufactured by Union Carbide Co.
0 ”,“ Celoxide 208 ”manufactured by Daicel Chemical Industries, Ltd.
3 ", manufactured by Daicel Chemical Industries, Ltd.," Eporide GT-30 "
2] and the like.

When a cationically polymerizable alicyclic epoxy compound is used, it is desirable to use a photocationic polymerization initiator. Specific examples of the cationic photopolymerization initiator include:
UVI-6990, UVI-6970, UVI-697
4, UVI-6950 (made by Union Carbide),
Examples include aryl sulfonium salts such as SP-150 and SP-170 (manufactured by Asahi Denka Co., Ltd.) and aryl iodonium salts such as FC-509 (manufactured by 3M Company).

Further, depending on the purpose, a sensitizer, a thermal polymerization catalyst, a thermal polymerization inhibitor, a surfactant, a slip agent, an antifoaming agent, a reactive or non-reactive diluent and the like are added to the coating agent. Is obtained.

The coating material of the present invention is applied to the surfaces of aluminum and steel metal cans and polyester film-coated drawn metal cans, as well as polyethylene terephthalate,
It is also applied to the surface of plastic films such as polyethylene, polypropylene, nylon, vinyl chloride, vinylidene chloride, and plastic molded products. As a coating method, roll coating, gravure coating, gravure offset coating, curtain flow coating, reverse coating, screen printing, spray coating, and dipping can be applied.

As a light source for photo-curing the ultraviolet-curable resin composition of the present invention and a coating agent containing the same, a light source containing light in the range of 200 to 450 nm is usually used, such as a high pressure mercury lamp, an ultrahigh pressure mercury lamp or a metal halide. A lamp, a gallium lamp, a xenon lamp, a carbon arc lamp or the like can be used. In addition, these light sources, infrared, far infrared,
It is also possible to use heat by hot air, high frequency heating, or the like.

[0034]

EXAMPLES The present invention will be described below with reference to Examples and Comparative Examples, but the present invention is not limited thereto. In the examples, "part" and "%" mean "% by weight" and "part by weight", respectively.

[0035]

Example 1 Bisphenol A type epoxy acrylate 80 parts (Ebecryl EB600 manufactured by Daicel UCB) Ketone formaldehyde resin (Tg: 51 ° C., Mn: 780) 20 parts (Synthetic resin AP manufactured by Huls) 20 parts chloroethyl vinyl ether Paint 1 was prepared by mixing 5 parts of 1-hydroxycyclohexyl phenyl ketone and stirring. A material obtained by laminating a 100 μm PET film on a tin-free steel plate with a thickness of 300 μm (hereinafter referred to as “PET
/ TFS ") PET film and thickness 30
A film thickness of 10 μm each on a 0 μm aluminum plate
And apply under high pressure mercury lamp of 80W / cm for 1
It was passed at a speed of 0 m / min to obtain a cured coating film.

Examples 2 to 9 and Comparative Examples 1 to 4 Paints were prepared according to the compounding ratios shown in Table 1, and Example 1 was used.
A coated film was obtained by coating in the same manner as in. In addition, after mixing and stirring in Examples 4 to 9, pigment dispersion was performed using a sand mill.

The cured coating films obtained in Examples 1 to 9 and Comparative Examples 1 to 4 were evaluated for adhesion, workability, retort resistance and coating film hardness by the following methods. Table 2 shows the results.

Adhesion: A cellophane tape peeling test was conducted based on JIS K5400, and the number of crosses where the coating film did not peel off was displayed.

Workability: The coated plate was punched into a 3 × 3 (3 cm in diameter, 3 cm in depth) cap with a press, and the height of peeling of the coating film on the side wall of the cap was measured.

Retort resistance: The cured coating film is treated in high-pressure hot water at 130 ° C. for 30 minutes to whiten the coating film, blister,
The adhesion was evaluated. ◎ No abnormality ○ Slight whitening of coating film △ Blister in coating film × Peeling of coating film

Coating hardness: Pencil hardness was measured according to JIS K5400.

[0042]

[Table 1]

[0043]

[Table 2]

[0044]

According to the present invention, a coating composition which is cured at a high speed by irradiation with ultraviolet rays and has excellent adhesion to metal cans and polyester film-coated drawn metal cans, processability, retort resistance, and coating hardness is obtained. .

Claims (8)

[Claims] 1. A radical-polymerizable acrylate and / or methacrylate compound (A), a non-radical-polymerizable compound (B), a vinyl ether compound (C), and a photoradical polymerization initiator (D) are contained. UV curable resin composition. 2. The ultraviolet curable resin composition according to claim 1, wherein the non-radical polymerizable compound (B) has a glass transition point of 40 ° C. or higher and 150 ° C. or lower. 3. The ultraviolet curable resin composition according to claim 1, wherein the non-radical polymerizable compound (B) is a ketone formaldehyde resin. 4. The ultraviolet-curable type according to claim 1, wherein the vinyl ether compound (C) is one or more selected from the group of the following formulas (1) to (4). Resin composition. Embedded image 5. The ultraviolet curable resin composition according to claim 1, further comprising a pigment (E). 6. A coating material comprising the ultraviolet curable resin composition according to any one of claims 1 to 5. 7. The coating agent according to claim 6, which coats a metal can. 8. The coating agent according to claim 6, which coats a polyester film-coated drawn metal can.