JPH0931144A - Ultraviolet-curable resin composition and laminate using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an ultraviolet-curable resin compsn. which is excellent in applicability and ultraviolet curability and gives a cured resin layer excellent in processibility, adhesive properties, and resistance to retort sterilization by using a specific acrylic epoxy resin. SOLUTION: This compsn. contains a monofunctional acrylic monomer and an acrylic epoxy resin mainly comprising a component represented by the formula (wherein R is H or methyl; ϕ<1> and ϕ<2> are each phenylene; and (n) is 2-9). In the acrylic epoxy resin, 20-50mol% of phenylene-methylene-phenylene (-ϕ<1> -CH2 -ϕ<2> ) bonds are pref. para-para bonds; esp. pref. 15-19mol% are ortho- ortho bonds, 48-52mol% ortho-para bonds, and 29-37mol% are para-para bonds. Pref. the wt. ratio of the acrylic epoxy resin to the monofunctional acrylic monomer in the compsn. is (80:20)-(20:80).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a UV-curable resin composition, and more particularly to an acrylic-epoxy resin-based UV-curable resin composition having excellent processability and retort resistance. The present invention also relates to a laminate having a layer formed from this resin composition.

[0002]

2. Description of the Related Art An ink or coating composition containing an ultraviolet curable resin does not have a problem of solvent volatilization during drying or baking, and it does not require heating of a printed portion or a coated material, so that it can be used in various applications. It is actually used and is being considered for use.

[0003] Conventionally, as an ultraviolet curable resin composition,
A combination of an epoxy resin and a cationic ultraviolet polymerization initiator, a combination of a urethane (meth) acrylate and an acrylate monomer, and an epoxy (meth) acrylate resin are known.

Japanese Patent Publication No. 6-18842 discloses a resin composition comprising an epoxy (meth) acrylate, a di (meth) acrylate, a monoethylenically unsaturated monomer and a photopolymerization initiator. .

[0005]

However, most of the known acrylic epoxy resins are derived from bisphenol A as phenols, and those derived from bisphenol F are also known. Since the molecular weight is fairly low, they are still sufficiently satisfactory for fields requiring workability and adhesion that can withstand harsh processing, especially for applications that require retort sterilization, such as cans for canning. It wasn't possible.

Therefore, an object of the present invention is to have excellent applicability (paintability and printability) and UV curability, and the cured resin layer has a combination of excellent processability, adhesion and retort sterilization resistance. An ultraviolet curable resin composition is provided.

Another object of the present invention is to provide a laminate having an ultraviolet curable resin layer having a combination of excellent processability, adhesion and retort sterilization resistance.

[0008]

According to the present invention, the following formula (1) is provided. In the formula, R is a hydrogen atom or a methyl group, and φ ¹ and φ
² is a phenylene group, and n is a number from 2 to 9. There is provided an ultraviolet-curable resin composition comprising an acrylic epoxy resin mainly composed of a component and a monofunctional acrylic monomer.

In the acrylic epoxy resin of the above formula (1), 20 to 50% of all units represented by the formula (2) —φ ¹ —CH ₂ —φ ² — are para-para bonds. It is particularly preferred that 15 to 19% are ortho-ortho linked, 48 to 52% are ortho-para linked and 29 to 37% are para-para linked. Preferred for the purpose.

In the ultraviolet curable resin composition of the present invention, the acrylic epoxy resin is 10 to 8 based on two components.
0% by weight and 20 to 80% by weight of monofunctional monomers should be present.

According to the present invention, also in a laminate comprising a metal substrate, a thermoplastic resin film layer provided on the substrate, and a thermosetting resin layer on a fill layer, the thermosetting resin layer is the above-mentioned ultraviolet ray. Provided is a laminate characterized by being formed from a curable resin composition.

[0012]

The ultraviolet-curable resin composition of the present invention is characterized by containing the acrylic epoxy resin of the formula (1) and a monofunctional acrylic monomer. That is, the acrylic epoxy resin of the formula (1) serves as the skeleton of this resin composition, while the monofunctional acrylic monomer functions as a diluent and as a polymerization curing agent. .

In the ultraviolet-curable resin composition of the present invention, it is preferable to use a monofunctional (meth) acrylic monomer in combination with the above-mentioned acrylic epoxy resin in terms of adhesion, workability and coatability of a coating film or the like. is important. That is, as shown in Comparative Example 3 described later, when the acrylic epoxy resin alone is used, satisfactory adhesion, processability,
The coatability cannot be obtained.

The acrylic epoxy resin and the monofunctional (meth) acrylic monomer are based on two components and the former 20 to 8 are used.
0% by weight, especially 30 to 60% by weight, the latter 80 to 2
It is preferable to use it in an amount of 0% by weight, particularly 70 to 30% by weight, and even if the amount of the acrylic epoxy resin is more than the above range or at least more than the above range, the workability and adhesion of the coating film and the like decrease To do. Further, those having a ratio in the above range are excellent in applicability and ultraviolet curability.

The acrylic epoxy resin of the formula (1) is obtained by reacting an epoxy resin component having epoxy groups at both ends with a (meth) acrylic acid component. The dihydroxy compound (bisphenol) in the epoxy resin component is used. The divalent arylene group derived from is a phenylene methylene phenylene group (-φ ¹ -CH ₂ -φ ^2- ), and the number of repetitions n in the formula (1) is in the range of 2 to 9. It is important in terms of adhesion, processability and applicability of the coating film.

See the example below. When an acrylic epoxy resin derived from a bisphenol A type epoxy resin was used as the acrylic epoxy resin (Comparative Example 7), the adhesion of the coating film was poor, as is clear from the results of the cross stitch test, and The coating film tends to peel off due to processing. Furthermore, this acrylic epoxy resin
The viscosity is high even when diluted with a monofunctional acrylic monomer, and it is still unsatisfactory in terms of applicability. On the contrary,
When an acrylic epoxy resin having an epoxy resin derived from bis (hydroxyphenyl) methane as a skeleton is used, adhesion and processability of the coating film are significantly improved, and
The viscosity of the resin is kept low and the applicability is remarkably improved.

The reason why the above-mentioned characteristics are improved by using an acrylic epoxy resin having an epoxy resin derived from bis (hydroxyphenyl) methane as a skeleton in the ultraviolet curable resin composition of the present invention is due to some limitation. However, the phenylene methylene phenylene (-
φ ¹ -CH ₂ -φ ^2- ) chain is phenylene propylidene phenylene Therefore, it is considered that the reason for this is that it has excellent ultraviolet curability and that there is little residual strain in the cured coating film.

The acrylic epoxy resin component in the resin composition of the present invention is phenylene methylene phenylene (-φ
It has already been pointed out that it has a ^1- CH ₂ -φ ^2- ) chain in the skeleton, but this phenylene methylene phenylene bond has three types of ortho-ortho bond, ortho-para bond, and para-para bond. There is a combination method of. Among the phenylene methylene phenylene group bonding methods, it is preferable that the para-para bond is contained in an amount of 20 to 50 mol%, particularly 27 to 37 mol%.

The acrylic epoxy resin skeleton contains 20 to 50 mol% of a para-para bond means that the remaining 50 to 80 mol% contains other bonds, namely ortho-para bond and ortho-ortho bond. And 40 to 60 mol% of ortho-para bonds, especially 48 to 52 mol%, and 10 to 20 mol% of ortho-ortho bonds,
In particular, the content is 15 to 19 mol%.

When the para-para bond is lower than the above range, the processability of the coating film is poor, and the hot water resistance is poor such as whitening by retort sterilization, and the chemical resistance is also unsatisfactory. On the other hand, when the number of para-para bonds is larger than the above range, the processability and adhesion of the cured coating film are poor, and the viscosity of the resin composition tends to increase.

Among the phenylene methylene phenylene bonds in the acrylic epoxy resin, those containing the ortho-ortho bond, the ortho-para bond and the para-para bond in the above amount ratios are applicable (paintability and printability), UV It is particularly suitable for the combination of curability and processability, adhesion and retort sterilization resistance of the cured resin layer.

The acrylic epoxy resin used in the present invention is characterized in that the number of repeats n in the general formula (1) is 2 to 9 and has a relatively high molecular weight. Number of iterations n is 2
In the case of acrylic ester, this means that the molecular weight corresponds to 965, which is different from the conventional acrylic epoxy resin having a number average molecular weight of about 430.

That is, when the conventional acrylic epoxy resin has a high molecular weight, the resin composition has a marked tendency to thicken and the applicability deteriorates, so that the molecular weight must be low.
The toughness of the resin film formed, there was a tendency to lack adhesion, etc., in the resin composition of the present invention, even if the acrylic epoxy resin is polymerized, the applicability is not impaired,
The toughness, adhesion, abrasion resistance, scratch resistance, etc. of the resin film can be remarkably improved.

The ultraviolet-curable resin composition of the present invention is useful as a packaging container, especially as a finishing varnish for cans and cups for heat sterilization such as retort sterilization, printing ink, top coat layer and the like. As a can for cans, a thermoplastic resin film such as polyester is laminated on the surface of a metal substrate, and the laminate is subjected to deep-drawing molding or drawing-ironing molding, which has excellent corrosion resistance and workability. Attention is paid. Although this polyester coating layer has excellent mechanical properties and barrier properties against corrosive components, it has poor adhesion to printing ink and finishing varnish, and the can body after applying these ink and varnish is necked-in. In addition, there is a problem in that the ink or varnish is easily peeled off when it is subjected to beading or the like.

On the other hand, when the resin composition of the present invention is applied to the polyester coating layer of the above-mentioned can in the form of ink or varnish and UV-cured, severe neck-in processing and bead processing are performed. Even when the contents are filled and sealed and the retort sterilization is performed after the contents are sealed, excellent adhesion is maintained and the commercial value can be increased.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION [Acrylic Epoxy Resin] The acrylic epoxy resin used in the present invention is mainly composed of the component represented by the formula (1), and the acrylic epoxy resin component of the formula (1) is , Formula (3) In the formula, φ ¹ and φ ² are phenylene groups, and n is a number from 2 to 9. Epoxy resin and formula (4) In the formula, R is a hydrogen atom or a methyl group. It is produced by adding acrylic acid or methacrylic acid represented by

The reaction of the epoxy resin with acrylic acid or methacrylic acid is carried out by a catalyst known per se, for example, amines such as triethylamine, diethylaniline and diethylbenzylamine, quaternary ammonium salts such as trimethylbenzylammonium chloride and alkyl styrene. Bottles or arylstibines are used. The reaction is generally 90
It can be carried out in the presence of catalytic amounts of catalysts at temperatures of from ~ 95 ° C. This reaction is preferably carried out in the presence of a small amount of a polymerization inhibitor such as quinones in order to prevent the polymerization of acrylic acid or methacrylic acid.

The epoxy resin of the above formula (3) can be obtained by condensing phenols mainly containing bis (hydroxyphenyl) methane with epihalohydrin.

The bis (hydroxyphenyl) methane contains a para-para-bonded [bis (4-hydroxyphenyl) methane] in an amount of 20 to 50 mol%, and more preferably a para-para-bonded one. To 50 mol%, especially 27 to 37 mol%, ortho-para bond 40 to 60 mol%, especially 48 to 52 mol%, ortho-ortho bond 10 to 20 mol%, especially 15
What contains about 19 to 19 mol% is used. The phenol used is bisphenol A, under the condition that at least 90% by weight of the phenol is bis (hydroxyphenyl) methane.
A binuclear phenol such as p- (4-hydroxyphenyl) phenol or a mononuclear dihydric phenol may be contained as an impurity.

The bis (hydroxyphenyl) methane is obtained by, but not limited to, dimerization of carboxylic acid and formaldehyde in the presence of a condensation catalyst to convert a binuclear phenol into a polynuclear phenol of a trinuclear phenol or higher. It is produced by separating the content of the para-para-bonded binuclear phenol by fractional crystallization, fractional dissolution, etc., and adjusting the amount.

The epoxy resin used for producing the acrylic epoxy resin is not limited to this, but the binuclear phenol and epihalohydrin are reacted in the presence of an alkali such as caustic soda to give an average of about 1 in the molecular chain. A liquid epoxy resin having a binuclear phenol skeleton is prepared, and the liquid epoxy resin and the binuclear phenol are heated in the presence or absence of a catalyst known per se to carry out a polyaddition reaction. Obtained. The properties such as the molecular weight and the degree of branching of the obtained epoxy resin are greatly affected by the production conditions at that time. The molecular weight of the epoxy resin varies depending on the purity of the liquid epoxy resin, the stoichiometric ratio of the liquid epoxy resin to the binuclear phenol, the reaction temperature, and the reaction time. That is, as the purity of the liquid epoxy resin increases, the molecular weight increases. The higher the stoichiometric ratio of the liquid epoxy resin and the binuclear phenol to 1: 1, the higher the molecular weight. Also, the higher the reaction temperature and the longer the reaction time, the higher the molecular weight. In the present invention, the number of iterations n described above is 2 to 9
Range.

[UV-Curable Resin Composition] The monofunctional acrylic monomer used in the present invention exhibits the function as a diluent and the function as a polymerization-curing agent. However, the present invention is not limited to this example. (Meth) acryloylmorpholine, isobonyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenol ethylene oxide modified (meth) acrylate, hydroxybutyl vinyl ether, 2-hydroxy-3-phenoxypropyl (meth) acrylate, tetrahydrofurfuryl ( (Meth) acrylate, hydrogenated dicyclopentadiene (meth) acrylate, dicyclopentadiene (meth)
Acrylate, dicyclopentadieneoxyethyl (meth) acrylate and the like.

The acrylic epoxy resin and the monofunctional (meth) acrylic monomer are based on two components, the former 20 to 8
0% by weight, especially 30 to 60% by weight, the latter 80 to 2
It is preferably used in a proportion of 0% by weight, particularly 70 to 30% by weight.

As a matter of course, the resin composition of the present invention contains a radical photopolymerization agent.

Typical examples of the photoradical polymerization initiator are benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and other benzoins and their alkyl ethers; acetophenone, 2,2-dimethoxy-2-phenylacetophenone. , 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexylphenyl ketone, 2-hydroxycyclohexylphenyl ketone, 2-methyl-1- [4- (methylthio) phenyl] -2- Morpholino-Propane-
Acetophenones such as 1-one; anthraquinones such as 2-methylanthraquinone and 2-amylanthraquinone; 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, and 2,4
Thioxanthones such as diisopropylthioxanthone, ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzophenones such as benzophenone or xanthones; 2,4,6-trimethylbenzoyl-diphenylphosphine oxide; bis (2,6-dimethoxybenzoyl) ) Acylphosphine oxides such as -2,4,4-tri-methylpentylphosphine oxide.

Such a photopolymerization initiator can be used in combination with one or more known photopolymerization accelerators such as benzoic acid-based or tertiary amine-based photopolymerization accelerators.

In the ultraviolet curable resin composition of the present invention, the photopolymerization initiator is used in an amount of 0.1 to 30 parts by weight, preferably 1 to 25 parts by weight, based on 100 parts by weight of the ultraviolet curable resin. Is preferred.

The UV-curable ink used in the present invention is difficult to define its viscosity because the above-mentioned UV-curable resin composition exhibits remarkable non-Newtonian behavior, but in general, the apparent viscosity at a shear rate of 1 sec ^-1 is 500 to 5
It is preferably in the range of 000 poise (p, 20 ° C.).

Suitable examples of the color pigment used in this ink are as follows, but of course the present invention is not limited thereto. Black pigments Carbon black, acetylene black, run black, aniline black. Yellow pigment Yellow lead, zinc yellow, cadmium yellow, yellow iron oxide, mineral fast yellow, nickel titanium yellow, navels yellow, naphthol yellow S, Hansa yellow G, Hansa yellow 10G, benzidine yellow G,
Benzidine Yellow GR, Quinoline Yellow Lake, Permanent Yellow NCG, Tartrazine Lake. Orange pigments Red mouth lead, molybdenum orange, permanent orange GTR, pyrazolone orange, Vulcan orange, induslen brilliant orange RK, benzidine orange G, induslen brilliant orange GK. Red pigment Bengala, cadmium red, lead red, cadmium mercury sulfide, permanent red 4R, lithol red, pyrazolone red, watching red calcium salt, lake red D, brilliant carmine 6B, eosin lake, rhodamine lake B, alizarin lake, brilliant carmine 3B. Purple pigment Manganese purple, fast violet B, methyl violet lake. Blue pigment Navy blue, cobalt blue, alkali blue lake, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, partially chlorinated phthalocyanine blue, first sky blue, indaslen blue B
C. Green pigment chrome green, chromium oxide, pigment green B,
Malachite Green Lake, Fanal Yellow Green G. White pigment Zinc white, titanium oxide, antimony white, zinc sulfide. Extender barite powder, barium carbonate, clay, silica, white carbon, talc, alumina white.

The above pigment is preferably used in an amount of 120 parts by weight or less, particularly 100 parts by weight or less, per 100 parts by weight of the resin composition.

If desired, a polymerization component other than an acrylic epoxy resin or a monofunctional acrylic monomer, such as a polyfunctional acrylic monomer or prepolymer or other vinyl monomer or prepolymer, can be added to the above resin composition. .

As the polyfunctional acrylic monomer, 1,6
-Hexanediol diacrylate (HDDA), 1,6-hexanediol dimethacrylate (HDDMA), neopentyl glycol diacrylate, neopentyl glycol dimethacrylate, ethylene glycol diacrylate (E
GDA), ethylene glycol dimethacrylate (EGDMA),
Polyethylene glycol diacrylate (PEGMA-A), polyethylene glycol diacrylate (PEGMA), polypropylene glycol diacrylate, polypropylene glycol dimethacrylate, butylene glycol diacrylate, butylene glycol dimethacrylate, pentaerythritol diacrylate, 1,4-butanediol di Acrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate,
Pentaerythritol triacrylate, dipentaerythritol hexaacrylate, tetramethylolmethane tetraacrylate, N, N, N ', N'-tetrakis (β
Acrylic ester of -hydroxyethyl) ethylenediamine, 2,2-bis [4- (3-methacryloyloxy-2-hydroxypropoxy) phenyl) propane and the like are used.

As the polyester prepolymer,
Polyesters containing an ethylenically unsaturated bond in the molecule, for example, ethylenically unsaturated polycarboxylic acids such as maleic acid, fumaric acid, itaconic acid, tetrahydrophthalic acid, etc., and isophthalic acid, trimellitic acid, pyromellitic acid , Adipic acid, sebacic acid, a combination with other acid components such as polymerized fatty acids, and polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, glycerin, neopentyl glycol, trimethylolpropane, pentaerythritol, and bisphenols. A polyester resin obtained by condensing is used.

Further, divinylbenzene, diallyl phthalate (DAP), diallyl isophthalate, diallyl adipate, diallyl glycolate, diallyl maleate, diallyl sebacate, triallyl phosphonate,
Other multifunctional monomers such as triallyl aconitate, trimellitic acid allyl ester, pyromellitic acid allyl ester may also be used.

Monomers or prepolymers other than the acrylic epoxy resin and the monofunctional acrylic monomer are 40 parts by weight or less per 100 parts by weight of the ultraviolet curable resin composition,
It is particularly preferable to use it in an amount of 30 parts by weight or less.

The UV-curable resin composition of the present invention may be blended with a compounding agent known per se according to a known formulation. Examples of such compounding agents include a defoaming agent such as silicone oil and a leveling agent. A fluorine-based surfactant, a silicone-based surfactant, an acrylic copolymer or the like, a thickener, a thickener or the like can be used as the above.

As the finishing varnish, the same varnish as the printing ink is used except that it has no coloring pigment and is excellent in transparency. Its viscosity is generally 1
It is preferably in the range of 00 to 200 centipoise (cp, 20 ° C.).

[Application and Curing] In the present invention, printing of the ultraviolet curable ink can be carried out by a known can-making printing method such as offset printing, lithographic printing, gravure printing, screen printing and the like. On the other hand, the application of the UV-curable finishing varnish can be performed using a gravure roll, an ordinary coating roll, or the like. The coating thickness of the finishing varnish should generally be in the range of 2 to 20 μm.

As ultraviolet rays used for curing the ink layer, etc.
Generally has a wavelength of 200 to 44, including the near ultraviolet region.
0 nm, in particular 240-420 nm, is used.
You. As ultraviolet light sources, halide lamps, high-pressure mercury lamps,
A low-pressure mercury lamp or the like is used. Ink layer and finishing varnish layer
The energy required for curing is
The advantage is that it requires significantly less, generally 500
Up to 5000 joules / m ^TwoEnergy is sufficient
You.

[Use] FIG. 1 showing an example of the laminate of the present invention.
In, this laminate is a thinned seamless can,
The thin seamless can 1 is formed by deep drawing (drawing-redrawing) or drawing-ironing of the resin-coated metal material described above, and includes a bottom portion 2 and a side wall portion 3. Side wall 3
A flange portion 5 is formed on the upper end of the through the neck portion 4. In this can 1, the side wall portion 3 is thinner than the bottom portion 2 by bending and stretching and ironing.

In FIG. 2 showing an example of the cross-sectional structure of the side wall portion of the thinned seamless can, the side wall portion 10 is formed on the metal substrate 11, the inner thermoplastic film 12 provided on the inner surface of the metal substrate 11, and the outer surface of the substrate. It comprises an outer thermoplastic film 14 provided, a titanium oxide-comprising UV-curable coating layer 16 on the outer film, a printing ink layer 17 on the coating layer and a finishing varnish layer 18 on the printing ink layer.

In FIG. 3 showing another example of the cross-sectional structure, the cross-sectional structure is the same as that of FIG. 2, but between the metal surface and the inner surface organic coating 12 and between the metal surface and the outer surface organic coating 14.
And the adhesive layers 15a and 15b are respectively interposed between and.

This thinned seamless can molded body (cup)
May be any as long as it has a thermoplastic resin film on the inner surface and the outer surface of the metal plate, and is obtained by molding an organic-coated metal plate into a cup.

This cup is obtained by subjecting the above-mentioned coated metal plate to drawing redrawing and ironing, drawing and bending and redrawing, drawing and bending and redrawing and ironing.

As the metal plate, various surface-treated steel plates and light metal plates such as aluminum are used.

As the surface-treated steel sheet, a cold-rolled steel sheet is annealed and then secondary cold-rolled, and one or more surface treatments such as zinc plating, tin plating, nickel plating, electrolytic chromic acid treatment and chromic acid treatment are performed. It can be used.
An example of a suitable surface-treated steel sheet is an electrolytic chromic acid-treated steel sheet, which is particularly provided with a metal chromium layer of 10 to 200 mg / m ² and a chromium oxide layer of 1 to 50 mg / m ² (metal chromium conversion). This is an excellent combination of coating film adhesion and corrosion resistance. Another example of a surface-treated steel plate is a hard tin plate having a tin plating amount of 0.5 to 11.2 g / m ² . This tin plate is preferably subjected to chromic acid treatment or chromic acid / phosphoric acid treatment so that the amount of chromium becomes 1 to 30 mg / m ^{2 in} terms of metal chromium. As still another example, an aluminum-coated steel sheet subjected to aluminum plating, aluminum pressure welding, or the like is used. Among these, the effect is particularly large when applied to the above-mentioned electrolytic chromic acid-treated steel sheet.

A so-called pure aluminum plate is used as the light metal plate.
Besides, an aluminum alloy plate is used. Corrosion resistance and corrosion resistance
An aluminum alloy plate excellent in terms of workability has a Mn: 0.2
To 1.5% by weight, Mg: 0.8 to 5% by weight, Zn:
0.25 to 0.3% by weight, and Cu: 0.15 to
0.25% by weight, with the balance being Al
You. These light metal plates also have a chromium
Is 20 to 300 mg / m ^TwoChromic acid treatment
Or it is desirable that chromic acid / phosphoric acid treatment is performed.
New

Thickness of metal plate, ie thickness of can bottom (tB)
Although it varies depending on the type of metal, the use or size of the container, it is generally good to have a thickness of 0.10 to 0.50 mm. Among them, in the case of a surface-treated steel sheet,
It is preferable to have a thickness of 0.10 to 0.30 mm, and in the case of a light metal plate, a thickness of 0.15 to 0.40 mm.

As the thermoplastic resin coated on the metal plate, a crystalline thermoplastic resin is preferable. Examples of the thermoplastic resin include polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer and ethylene. Olefin resin films such as acrylic ester copolymers and ionomers; polyethylene terephthalate;
Polyesters such as polybutylene terephthalate and ethylene terephthalate / isophthalate copolymer; polyamides such as nylon 6, nylon 6,6, nylon 11 and nylon 12; polyvinyl chloride; polyvinylidene chloride;

The thermoplastic resin coating layer contains an inorganic filler (pigment) for the purpose of concealing the metal plate and assisting the transmission of the wrinkle holding force to the metal plate during drawing-redrawing. You can In addition, a compounding agent for a film known per se, for example, an antiblocking agent such as amorphous silica, various antistatic agents, a lubricant, an antioxidant, and an ultraviolet absorber may be added to the film according to a known formulation. it can.

Examples of the inorganic filler include inorganic white pigments such as rutile type or anatase type titanium dioxide, zinc white, and gloss white; barite, precipitated barium sulfate, calcium carbonate, gypsum, precipitated silica, aerosol, talc, calcined or Is a white extender pigment such as unsintered clay, barium carbonate, alumina white, synthetic or natural mica, synthetic calcium silicate, magnesium carbonate; black pigment such as carbon black and magnetite; red pigment such as red iron oxide; yellow pigment such as siena. And blue pigments such as ultramarine blue and cobalt blue. These inorganic fillers can be incorporated in an amount of 10 to 500% by weight, particularly 10 to 300% by weight, based on the resin. It has already been pointed out that titanium dioxide has a particularly high hiding power and is preferably filled in the outer resin layer.

The coating of the coated thermoplastic resin on the metal plate is performed by a heat fusion method, dry lamination, an extrusion coating method or the like, and the adhesiveness (heat fusion property) between the coating resin and the metal sheet.
When the content is insufficient, for example, a urethane-based adhesive, an epoxy-based adhesive, an acid-modified olefin resin-based adhesive, a copolyamide-based adhesive, a copolyester-based adhesive, or the like can be interposed.

The thickness of the thermoplastic resin is preferably in the range of generally 3 to 50 μm, especially 5 to 40 μm. In the case of heat fusion using a film, it may be unstretched or stretched.

As a particularly suitable film, a polyester mainly containing ethylene terephthalate units is formed into a film by a T-die method or an inflation film forming method, and this film is biaxially stretched sequentially or simultaneously at a stretching temperature and stretched. The film produced by heat-fixing the latter film can be mentioned.

As the raw material polyester, polyethylene terephthalate itself can be used under the conditions of extremely limited stretching, heat setting and laminating, but it is necessary to lower the maximum crystallinity that can be achieved by the film to reduce impact resistance and processability. It is desirable that the copolymer ester unit other than ethylene terephthalate is introduced into the polyester for this purpose. It is particularly preferable to use a biaxially stretched film of a copolymerized polyester mainly composed of ethylene terephthalate units and containing a small amount of other ester units and having a melting point of 210 to 252 ° C. The melting point of homopolyethylene terephthalate is generally from 255 to 265 ° C.

Generally, 70 mol% or more, especially 75 mol% or more of the dibasic acid component in the copolyester is composed of a terephthalic acid component, and 70 mol% or more, especially 75 mol% or more of the diol component is composed of ethylene glycol, It is preferable that 1 to 30 mol%, particularly 5 to 25% of the dibasic acid component and / or diol component is composed of a dibasic acid component other than terephthalic acid and / or a diol component other than ethylene glycol.

Dibasic acids other than terephthalic acid include aromatic dicarboxylic acids such as isophthalic acid, phthalic acid and naphthalenedicarboxylic acid: alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid: succinic acid, adipic acid, sebacic acid, dodecane Aliphatic dicarboxylic acids such as dionic acid: One or a combination of two or more thereof may be mentioned. As the diol component other than ethylene glycol, propylene glycol,
1,4-butanediol, diethylene glycol, 1,
One or more of 6-hexylene glycol, cyclohexane dimethanol, an ethylene oxide adduct of bisphenol A and the like can be mentioned. Of course, the combination of these comonomers must be such that the melting point of the copolyester is within the above range.

The copolyester used should have a molecular weight sufficient to form a film, for which an intrinsic viscosity (IV) of 0.55 to 1.9 dl / g, in particular 0.65 to 1.4 dl / g. Those in the range of g are desirable.

The film is generally stretched at 80 to 110 ° C.
At a temperature of, the area stretching ratio is preferably in the range of 2.5 to 16.0, particularly 4.0 to 14.0.
It is good to carry out in the range of 30 ° C.

It is important that the copolyester film is biaxially stretched. The degree of biaxial orientation can also be confirmed by a polarization fluorescence method, a birefringence method, a density gradient tube method, or the like.

At the time of lamination, for the purpose of preventing excessive crystallization, the time taken for the film to be laminated to pass through the crystallization temperature range is shortened as much as possible, preferably this temperature range is within 10 seconds, particularly 5 seconds. Try to pass within. For this,
When laminating, only the metal material is heated, and the laminated body is forcibly cooled immediately after laminating the films. For cooling, direct contact with cold air or cold water or pressure contact of a forcedly cooled cooling roller is used. It is to be understood that the degree of crystal orientation can be relaxed by heating the film to a temperature near the melting point during the lamination and quenching after lamination.

When an adhesive primer is used, it is generally desirable to subject the surface of the film to a corona discharge treatment in order to enhance the adhesion to the film. The degree of the corona discharge treatment was such that the wetting tension was 44
It is desirable that the dyne / cm is not less than that.

In addition, it is also possible to subject the film to a plasma treatment, a flame treatment or the like which is known per se for an adhesion-improving surface treatment or a urethane resin-based or modified polyester resin-based adhesion-improving coating treatment. .

The adhesive primer optionally provided between the polyester film and the metal material exhibits excellent adhesion to both the metal material and the film. A typical primer paint excellent in adhesion and corrosion resistance is a phenol epoxy paint composed of a resol type phenol aldehyde resin derived from various phenols and formaldehyde, and a bisphenol type epoxy resin, Particularly, a phenol resin and an epoxy resin are mixed in a ratio of 50: 5
0 to 5:95 weight ratio, especially 40:60 to 10:90
Is a paint contained in a weight ratio of

The adhesive primer layer is generally 0.3 to 5
It is preferable to provide it with a thickness of μm. The adhesive primer layer may be provided in advance on a metal material or may be provided in advance on a polyester film.

The metal cup-shaped container is molded by a means known per se so that the side wall portion is thinned, for example, drawing redrawing and ironing, drawing and bending and redrawing, drawing and bending and redrawing and ironing. Done in.

For example, according to deep-drawing bending-drawing (drawing-bending-extending redrawing), a front drawing cup formed from a coated metal plate is inserted into the annular holding member and below the cup. Hold with re-drawing dies located. The redrawing punch is arranged coaxially with the holding member and the redrawing die so as to be able to enter and exit the holding member.
The redrawing punch and the redrawing die are relatively moved so as to mesh with each other.

As a result, the side wall portion of the front draw cup is bent from the outer peripheral surface of the annular holding member through its curvature corner portion and radially inwardly perpendicularly to the annular bottom surface of the annular holding member and the upper surface of the redrawing die. It passes through the part specified by and and is bent almost perpendicular to the axial direction by the action corner of the redrawing die.
It can be molded into a deep drawing cup having a smaller diameter than the front drawing cup.

At this time, the radius of curvature (Rd) of the working corner portion of the redrawing die is set to 1 to 2.9 times, particularly 1.5 to 2.9 times, the metal plate thickness (tB). As a result, it is possible to effectively reduce the wall thickness by bending and pulling the side wall portion. In addition, the variation in the thickness between the lower portion and the upper portion of the side wall portion is eliminated, and uniform thickness reduction can be achieved over the whole. Generally, the side wall of the can body has the following formula (I). In the equation, tB is the thickness of the base plate, and tW is the thickness of the side wall. Can be reduced to a thickness of 5 to 45%, particularly 5 to 40%.

For deep drawn cans, the following formula (II) Wherein, D is the diameter of the sheared laminate material, d is the punch diameter, in the aperture ratio R _D as defined in 1 in one step.
It is preferable to be in the range of 1 to 3.0, and in the range of 1.5 to 5.0 in total.

An ironing die is arranged behind the redrawing or bending / stretching redrawing, and the thinning rate including ironing is 5 to 70%, particularly 10 to 60% with respect to the side wall portion.
And can be thinned by ironing.

For drawing, etc., various lubricants such as liquid paraffin, synthetic paraffin, edible oil, hydrogenated edible oil, palm oil, various natural waxes, and polyethylene wax are applied to the coated metal plate or further cups for molding. Good to do. The amount of the lubricant to be applied varies depending on the kind thereof, but is generally 0.1 to 10 mg / dm ² , especially 0.2 to 10 mg / dm ² .
It is preferably in the range of 5 to 5 mg / dm ² , and the application of the lubricant is performed by spraying the lubricant in a molten state onto the surface.

In order to improve the drawability of the cup,
Advantageously, the temperature of the resin-coated squeeze cup is preset to a temperature not lower than the glass transition point (Tg) of the coating resin, particularly not higher than the thermal crystallization temperature, and molding is carried out in a state in which plastic flow of the resin coating layer is facilitated. Is.

The inner surface organic coated metal cup after molding is
After the so-called trimming, in which the ear portion of the cup opening is cut, the printing process is performed. Prior to this trimming treatment, the cup after molding is covered with the glass transition point (T
g) or more and heating to a temperature lower than the melting point, so that the distortion of the coating resin can be alleviated. This operation is particularly effective in the case of a thermoplastic resin in order to increase the adhesion between the coating and the metal.

Printing, coating and UV curing are carried out as described above, but necking-in and flanging of the printing cup are carried out by means known per se. The neck-in processing can be performed in one or more stages by a known neck-in processing method, for example, a die method or a spin neck-in method.

The following formula (III) In the formula, RL represents the outer diameter of the can body before neck-in processing, and R
S represents the outer diameter of the can body of the neck-in processing part. The neck-in processing rate (N R) defined by is preferably in the range of 1.01 to 1.10, particularly 1.02 to 1.07 in one step, and in the case of multi-step neck-in processing, 1.10
To 1.30, especially 1.11 to 1.25.

It is recommended that the neck-in process be performed at a temperature of 50 ° C. or higher and lower than the glass transition temperature (Tg) of the coating. That is, at a temperature above the Tg of the coating, the coating itself is scratched due to engagement between the coating and a tool, and on the other hand, at a temperature lower than 50 ° C, the coating causes plastic flow of the metal material during neck-in processing. And the coating defects such as the peeling of the coating and the generation of cracks are likely to occur. At the time of neck-in processing, it is optional that a lubricant or a lubricant can be applied to the can body that comes into contact with the tool, or that the surface of the tool that comes into contact with the can body can be formed of a material having excellent lubricating performance.

The necked-in cup engages the flanging die at its open end and is flanged to form a flange for double winding with the can end.

The metal cup-shaped container after processing is heated at a temperature not lower than the glass transition point (Tg) of the organic coating on the inner surface side, particularly preferably at a temperature not lower than Tg + 100 ° C., so that the neck-in processing and the flange processing part It is desirable to effectively release the residual strain in the inner surface resin coating.

This heating may be performed on the entire container by using a hot air heating furnace, an infrared heating furnace, or the like, or may be performed only on the neck-in processing of the cup and the flange processing portion or its vicinity.

[0091]

The present invention will be described in more detail with reference to the following examples.

Evaluation of coating film performance of the resin compositions obtained in Examples and Comparative Examples was carried out as follows. (A) Preparation of cured coating film The resin compositions obtained in Examples and Comparative Examples were applied to a laminated steel sheet in which a biaxially stretched PET film (25 μm in thickness) was heat-bonded to a tin-free steel sheet having a thickness of 0.18 mm. 8
It was coated with μm. Output 1 if the paint is clear paint
The coating film was cured by irradiating it with 200 mJ of ultraviolet light from a 60 W / cm high pressure mercury lamp. On the other hand, when the coating material was a white coating in which titanium oxide was dispersed, 100 mJ of ultraviolet light was irradiated from a metal halide lamp doped with gallium and having an output of 160 W / cm to cure the coating film.
For measurement of irradiation dose, E. I. T. A UV meter (Fusion Systems) was used. (B) Adhesion The adhesion was evaluated by the Goban eye adhesion test, and the adhesion was evaluated based on the remaining area%. (C) Workability Workability was evaluated by the DuPont impact test. Using a 1/2 inch heart, a 300 g block was dropped from a height of 50 cm to deform the coated plate, and the presence or absence of peeling of the coating film on the deformed portion was examined. Then, a cellophane tape peeling test was carried out by an ordinary method, and the presence or absence of peeling of the coating film on the deformed portion was examined. (D) Retort resistance Distilled water was placed in a stainless steel container, the coated plate was immersed in the container, and then the stainless container was inserted into a retort kettle to carry out retort treatment at 130 ° C. for 30 minutes. After the end of the retort, the coated plate was observed to check for whitening and blisters.

[Production of epoxy resin] 2,2'-dihydroxydiphenylmethane / 2,4'-dihydroxydiphenylmethane / 4,4'-dihydroxydiphenylmethane compounding ratio 17/51/32 by weight, isomer of dihydroxydiphenylmethane A liquid epoxy resin (EP-1) was obtained by a conventional method using the mixture (PF-1) and epichlorohydrin. Then, (EP-1) and the above (P
F-1) and a solid epoxy resin (E
P-2 to 5) were produced.

2,2'-dihydroxydiphenylmethane / 2,4'-dihydroxydiphenylmethane / 4,4 '
-Dihydroxydiphenylmethane content of 13 by weight
/ 60/27 isomer mixture of dihydroxydiphenylmethane (PF-2) and epichlorohydrin,
Liquid epoxy resin (EP-6) was obtained according to a conventional method. Then, using (EP-6) and the above-mentioned (PF-2), a solid epoxy resin (EP-7) was produced by a conventional method.

2,2'-dihydroxydiphenylmethane / 2,4'-dihydroxydiphenylmethane / 4,4 '
-Dihydroxydiphenylmethane content of 13 by weight
/ 35/52 dihydroxydiphenylmethane isomer mixture (PF-3) and epichlorohydrin,
A liquid epoxy resin (EP-8) was obtained according to a conventional method. Then, using (EP-8) and the above (PF-3), a solid epoxy resin (EP-9) was produced by a conventional method.
2,2'-dihydroxydiphenylmethane / 2,4'-
The mixing ratio of dihydroxydiphenylmethane / 4,4'-dihydroxydiphenylmethane is 15/70/15 by weight.
Using a mixture of isomers of dihydroxydiphenylmethane (PF-4) and epichlorohydrin, a liquid epoxy resin (EP-10) was obtained by a conventional method. Then
Using (EP-10) and the above (PF-4), a solid epoxy resin (EP-11) was produced by a conventional method. Table 1 shows the number average molecular weight and epoxy equivalent of the produced epoxy resin.
Shown in

[Production of Epoxy Acrylate] EP-1
5 and EP-7, EP-9, and EP-11 were added with acrylic acid by a conventional method to produce epoxy acrylate. During the acrylate reaction,
The solid epoxy resin was previously dissolved in a monofunctional or polyfunctional acrylate monomer in a weight ratio of 1: 1 and acrylic acid and a catalyst were added to this resin solution to carry out an addition reaction. The details of the obtained epoxy acrylate are shown in Table 2.

Further, a commercially available bisphenol A type epoxy resin (Yukaka Shell Epoxy Co., Ltd., Epicoat 100) is used.
Epoxy acrylate was also prepared from 4) as a comparison. The details of the obtained epoxy acrylate are shown in Table 2. The viscosity of the epoxy acrylate solution (R-6) prepared from EP-4 having the same number average molecular weight and epoxy equivalent as Epicoat 1004 is 250 P at 60 ° C. On the other hand, the viscosity of the acrylate compound solution (R-11) of Epicoat 1004 was as viscous as 450 P at 60 ° C., and it was difficult to prepare a coating material in an appropriate viscosity range using R-11.

Example 1 R-2 60 parts Acryloylmorpholine (monofunctional monomer) 20 parts Neopentyl glycol hydroxypivalate diacrylate 20 parts (Bifunctional monomer) 1-hydroxycyclohexyl phenyl ketone 5 parts Processability, adhesion, A cured coating film having good retort resistance was obtained.

Example 2 R-3 50 parts Phenol ethylene oxide modified (n = 2) acrylate 10 parts (monofunctional monomer) Phenoxyethyl acrylate (monofunctional monomer) 20 parts Hydroxybutyl vinyl ether (monofunctional monomer) 5 parts Neopentyl Glycol hydroxypivalate diacrylate 15 parts (bifunctional monomer) 1-hydroxycyclohexyl phenyl ketone 5 parts A cured coating film having good processability, adhesion, and retort resistance was obtained.

Example 3 R-4 50 parts Isobornyl acrylate (monofunctional monomer) 20 parts 2-Hydroxy-3-phenoxypropyl acrylate 30 parts (monofunctional monomer) 1-hydroxycyclohexyl phenyl ketone 5 parts Workability, adhesion A cured coating film having good retort resistance was obtained.

Example 4 R-5 40 parts Acryloylmorpholine (monofunctional monomer) 40 parts 2-Hydroxy-3-phenoxypropyl acrylate 20 parts (monofunctional monomer) 1-hydroxycyclohexylphenyl ketone 5 parts Processability, adhesion A cured coating film having good retort resistance was obtained.

Example 5 R-1 20 parts R-6 30 parts Acryloylmorpholine (monofunctional monomer) 40 parts 2-Hydroxy-3-phenoxypropyl acrylate 10 parts (monofunctional monomer) 1-hydroxycyclohexyl phenyl ketone 5 parts A cured coating film having good processability, adhesion, and retort resistance was obtained.

Example 6 30 parts R-2 20 parts R-7 20 parts isobonyl acrylate (monofunctional monomer) 20 parts Phenol ethylene oxide modified (n = 2) acrylate 20 parts (monofunctional monomer) TMPTA (trifunctional monomer) 10 Parts 1-Hydroxycyclohexyl phenyl ketone 5 parts A cured coating film having good workability, adhesion, and retort resistance was obtained.

Example 7 R-1 10 parts R-5 40 parts Acryloylmorpholine (monofunctional monomer) 40 parts Neopentyl glycol hydroxypivalate diacrylate 10 parts (bifunctional monomer) 2,4,6-trimethylbenzoyldiphenyl Phosphine oxide 2 parts 1-Hydroxycyclohexyl phenyl ketone 3 parts Rutile titanium oxide 100 parts A cured coating film having good workability, adhesion and retort resistance was obtained.

Example 8 R-1 10 parts R-2 30 parts R-4 10 parts Acryloylmorpholine (monofunctional monomer) 40 parts Neopetyl glycol hydroxypivalate diazulylate 10 parts (bifunctional monomer) Bis (2 , 6-Dimethoxybenzoyl) -2,4,4 0.75 parts-trimethylpentylphosphine oxide 2-hydroxy-2-methyl-1-phenylpropane-2.25 parts 1-one 1-hydroxycyclohexylphenylketone 3 parts rutile Type titanium oxide 100 parts A cured coating film having good workability, adhesion, and retort resistance was obtained.

Comparative Example 1 A coated plate was prepared in the same manner as in Example 1 except that 2-hydroxy-3-phenoxypropyl acrylate was used instead of R-2. The adhesiveness and workability were good, but the roughened coating film was observed after retort.

Comparative Example 2 R-1 40 parts Acryloylmorpholine (monofunctional monomer) 40 parts Neopentyl glycol hydroxypivalate diacrylate 20 parts (Bifunctional monomer) 1-hydroxycyclohexyl phenyl ketone 5 parts Containing the resin of the present invention Since it was not applied, the adhesion was poor, and the coating film was completely peeled off by the goggles test.

Comparative Example 3 R-5 60 parts Neopentyl glycol hydroxypivalate diacrylate 40 parts (bifunctional monomer) 1-hydroxycyclohexyl phenyl ketone 5 parts Since no monofunctional monomer is contained, both adhesion and processability are poor. It was

Comparative Example 4 A coated plate was prepared in the same manner as in Example 2 except that R-8 was used instead of R-3. As a result of using the oligomer in which the compounding ratio of the phenol isomers deviated from the range of the present invention, the adhesiveness was remarkably reduced as compared with Example 2.

Comparative Example 5 A coated plate was prepared in the same manner as in Example 2 except that R-9 was used instead of R-3. As a result of using the oligomer in which the compounding ratio of the phenol isomers deviated from the range of the present invention, the adhesiveness was remarkably reduced as compared with Example 2.

Comparative Example 6 A coated plate was produced in the same manner as in Example 2 except that R-10 was used instead of R-3. As a result of using an oligomer in which the compounding ratio of the phenol isomers deviates from the range of the present invention, the adhesiveness and processability were poorer than in Example 2, and the coating film was whitened by the retort treatment.

Comparative Example 7 A coated plate was produced in the same manner as in Example 5 except that R-11 was used instead of R-6. Since the epoxy acrylate produced from the bisphenol A type epoxy resin was blended, the viscosity was high and it was difficult to obtain a uniform coating film having a thickness of 8 μm at room temperature, but the coating material was heated to 50 ° C. and applied. The obtained coating film was inferior in adhesion to Example 5. The results of Examples and Comparative Examples are summarized in Table 3.

[0113]

[Table 1]

[0114]

[Table 2]

[0115]

[Table 3]

[0116]

EFFECTS OF THE INVENTION According to the present invention, by using a combination of a specific acrylic epoxy resin and a monofunctional acrylic monomer, it has excellent application properties (paintability and printability), ultraviolet curability, and curing. It was possible to provide an ultraviolet-curable resin composition in which the resin layer has a combination of excellent processability, adhesion and retort sterilization resistance. This resin composition is useful as a printing ink, a finishing varnish, a white coat, or the like for a can for canning, especially a can having a thermoplastic resin film coating.

[Brief description of drawings]

FIG. 1 is a side view showing an example of a laminate (thinned seamless can) of the present invention.

FIG. 2 is a sectional view showing an example of a sectional structure of a side wall portion of the thinned seamless can of FIG.

3 is a cross-sectional view showing another example of the cross-sectional structure of the side wall portion of the thin seamless can of FIG.

[Explanation of symbols]

 1 Thinned Seamless Can 2 Bottom 3 Sidewall 4 Neck 5 Flange 10 Sidewall 11 Metal Substrate 12 Inner Thermoplastic Film 14 Outer Thermoplastic Film 15a, 15b Adhesive Layer 16 Titanium Oxide Blended Ultraviolet Curing Coating Layer 17 Printing Ink Layer 18 Finishing varnish layer

Claims (5)

[Claims] 1. The following formula (1) In the formula, R is a hydrogen atom or a methyl group, and φ ¹ and φ
² is a phenylene group, and n is a number from 2 to 9. An ultraviolet-curable resin composition comprising an acrylic epoxy resin mainly composed of a component represented by and a monofunctional acrylic monomer. 2. In the acrylic epoxy resin of the formula ( ¹ ), 20 to 50% of all units represented by the formula (2) —φ ¹ —CH ₂ —φ ² —. -The resin composition according to claim 1, which is a para-bond. 3. In the acrylic epoxy resin of the formula ( ¹ ), 15 to 19% of all units represented by the formula (2) -φ ¹ -CH ₂ -φ ² --... (2) are ortho. -The resin composition according to claim 1, wherein the resin composition is ortho-bonded, 48 to 52% is ortho-para-bonded, and 29 to 37% is para-para-bonded. 4. The acrylic epoxy resin is 10 to 80% by weight and the monofunctional monomer is 20 to 80, based on two components.
The resin composition according to claim 1, which is present in a weight percentage. 5. A laminate comprising a metal substrate, a thermoplastic resin film layer provided on the substrate, and a thermosetting resin layer on the film layer, wherein the thermosetting resin layer is any one of claims 1 to 4. A laminate formed by UV curing of the UV curable resin composition described in 1.