JP3098097B2 - Laminate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminate, and more particularly, to a laminate having a coating having excellent water resistance and excellent adhesion.

[0002]

2. Description of the Related Art An ionomer resin such as a partially neutralized product obtained by neutralizing a part of a carboxyl group of an ethylene-methacrylic acid copolymer in a side chain with a metal cation is used for various base materials, especially for metals. It is well known to have good adhesion. Also, the coating film made of this ionomer resin,
It is also known to use this ionomer resin as a rust preventive for metal substrates because of its excellent water resistance. further,
It is known that an ionomer resin can be used as an aqueous dispersion because it can be easily dispersed in water.
Therefore, an aqueous dispersion containing the ionomer resin is applied to a base material such as a metal, for example, a steel sheet to form a rust-proof layer made of the ionomer resin, and a rust-proof steel sheet is manufactured.

[0003] In recent years, with the diversification of uses and higher grades of rust-preventive steel sheets, rust-preventive steel sheets which have been conventionally used only by applying a rust-preventive agent to a base material have been used for coloring. Further, there has been an increasing demand for forming a film made of a curable resin such as a paint.

[0004]

However, the rust-preventive layer made of an ionomer resin has poor adhesion to a coating film made of a curable resin such as a paint, and a paint or the like is overcoated on the ionomer resin coating film. Even when applied, good coating could not be formed.

Accordingly, an object of the present invention is to provide a rust preventive layer having excellent water resistance and adhesion to metals and the like, and a curable resin layer such as a paint and a rust preventive layer formed on the rust preventive layer. An object of the present invention is to provide a laminate having excellent adhesion.

[0006]

In order to solve the above-mentioned problems, the present invention provides a metal substrate (A), a rust-preventive layer (B) mainly containing a reaction product of an ionomer resin and an epoxy group-containing compound. ) And a curable resin layer (C) laminated on the metal substrate (A) via the rust prevention layer (B).

The reaction product (B) of the ionomer resin and the epoxy group-containing compound is composed of 100 parts by weight of the ionomer resin and 0.05 to 50 of the water-soluble polyvalent epoxy group-containing compound.
Of an aqueous dispersion composition containing at least one part by weight.

It is preferable that the curable resin layer (C) is made of at least one selected from urethane resin, melamine resin and acrylic resin.

Hereinafter, the laminate of the present invention will be described in detail.

The laminate of the present invention comprises a metal substrate (A), a rustproof layer (B), and a curable resin layer laminated on the metal substrate (A) via the rustproof layer (B). (C). The rust preventive layer (B) and the curable resin layer (C) may be laminated on one surface of the metal substrate (A) or may be laminated on both surfaces of the metal substrate (A).

In the laminate of the present invention, the metal substrate (A)
Is not particularly limited, and examples thereof include a metal plate made of a metal element such as aluminum, iron, copper, nickel, and zinc, and an alloy plate. The metal substrate (A) may be subjected to a surface treatment, for example, may be subjected to polishing treatment, plating, or the like.

The shape, size, thickness and the like of the metal substrate (A) are appropriately selected according to the use of the laminate of the present invention.

The rust preventive layer (B) is mainly composed of a reaction product of an ionomer resin and an epoxy group-containing compound, and is usually composed of an ionomer resin (b1) and a water-soluble polyvalent epoxy compound (b2). And an aqueous dispersion composition comprising:

The ionomer resin, which is the component (b1) of the aqueous dispersion composition, comprises a polymer main chain mainly composed of hydrocarbons, has a carboxyl group in a side chain, and at least a part of the carboxyl group is contained. It is a polymer neutralized with metal cations. Specific examples of the ionomer resin include a partially neutralized product of a copolymer of ethylene and an unsaturated carboxylic acid, wherein at least a part of the contained carboxyl group is neutralized with a metal cation. The ethylene-unsaturated carboxylic acid copolymer constituting the main skeleton of the ionomer resin may be a random copolymer,
A graft copolymer of unsaturated carboxylic acid to polyethylene may be used, and a random copolymer is preferable in terms of transparency.

The unsaturated carboxylic acid which is a component of the ethylene-unsaturated carboxylic acid copolymer includes an unsaturated carboxylic acid having 3 to 8 carbon atoms. Specific examples of the unsaturated carboxylic acid having 3 to 8 carbon atoms include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, isocrotonic acid, citraconic acid, allyl succinic acid, mesaconic acid, glutaconic acid, Nadic acid (endocis-bicyclo [2,2,1] hept-2-ene-5,6
-Dicarboxylic acid), methylnadic acid, tetrahydrophthalic acid, methylhexahydrophthalic acid and the like. Of these, methacrylic acid is particularly preferred.

The ethylene-unsaturated carboxylic acid copolymer constituting the main skeleton of the ionomer resin (b1) may contain a third component in addition to ethylene and the unsaturated carboxylic acid. Examples of the third component include unsaturated carboxylic esters such as methyl (meth) acrylate, ethyl (meth) acrylate and isobutyl (meth) acrylate, and vinyl esters such as vinyl acetate.

The ethylene content in the ethylene-unsaturated carboxylic acid copolymer is usually from 95 to 60% by weight.
And preferably 92 to 75% by weight. Further, the content of the unsaturated carboxylic acid is usually 5 to 40% by weight, particularly preferably in the range of 8 to 25% by weight.
When the ethylene-unsaturated carboxylic acid copolymer contains a third component, the third component is preferably present in an amount of 40% by weight or less.

In the ionomer resin (b1) of the present invention, the metal cation neutralizing at least a part of the carboxyl group in the side chain of the ethylene-unsaturated carboxylic acid copolymer includes, for example, 1 to 3 Monovalent metal cations are preferred, and monovalent metal cations are preferred in that an ionomer resin having good emulsifying properties can be obtained. Of these monovalent metal cations, sodium and potassium are particularly preferred.

The ratio of the carboxyl group neutralized with the metal cation to the total carboxyl group in the side chain of the ethylene-unsaturated carboxylic acid copolymer, that is, the degree of neutralization, is excellent in the adhesion of the coating film. It is usually about 20 to 100%, preferably about 30 to 80%, in that an aqueous dispersion having good stability can be obtained.

This ionomer resin (b1) is AST
The MFR (190 ° C.) according to MD 1238 is 0.0
It is preferably 5 to 100 g / 10 min, and particularly preferably 0.1 to 50 g / 10 min.

The production of the ionomer resin (b1)
For example, a compound having ethylene and an unsaturated carboxylic acid, and if necessary, the third component is copolymerized by a high-pressure radical polymerization method, and a carboxyl group of the obtained ethylene-unsaturated carboxylic acid copolymer has the metal cation. And a method of graft copolymerizing an unsaturated carboxylic acid to polyethylene and neutralizing a carboxyl group of the obtained copolymer with the compound having a metal cation. . In this production, the required components may be supplied to an extruder and melted and kneaded for the reaction, or the reaction may be performed in an appropriate solution.

The epoxy group-containing compound as the component (b2) of the aqueous dispersion composition includes carboxylic acid and 2,2
Glycidyl esters obtained by a reaction with 3-epoxypropanol and the like, and glycidyl ethers obtained by a reaction of epichlorohydrin with a monovalent or polyvalent metal alkoxide, and the like can be given.

Examples of carboxylic acids for obtaining glycidyl esters include saturated monocarboxylic acids such as acetic acid, propionic acid, butyric acid and valeric acid; saturated dicarboxylic acids such as malonic acid, succinic acid, glutaric acid and adipic acid; Aromatic carboxylic acids such as benzoic acid and phthalic acid; unsaturated monocarboxylic acids such as acrylic acid and methacrylic acid; maleic acid, fumaric acid, itaconic acid, crotonic acid, isocrotonic acid, citraconic acid, allyl succinic acid, mesaconic acid, and glutacon Acid, nadic acid (endosis-bicyclo [2,2,1]
And unsaturated dicarboxylic acids such as hept-2-ene-5,6-dicarboxylic acid, methylnadic acid, tetrahydrophthalic acid and methylhexahydrophthalic acid. One or a combination of two or more of these carboxylic acids may be contained in the glycidyl esters.

Specific examples of glycidyl esters used as the epoxy group-containing compound (b2) include diglycidyl adipate, diglycidyl phthalate, and diglycidyl terephthalate.

The monovalent or polyvalent metal alkoxide for obtaining the glycidyl ether used as the epoxy group-containing compound (b2) is a compound obtained by reacting a monovalent or polyvalent alcohol with a metal. Examples of the monohydric alcohol include methanol, ethanol, propanol, butanol, hexanol and the like, and examples of the polyhydric alcohol include polyhydric alcohols such as ethylene glycol, resorcin and glycerin. Examples of the metal include alkali metals such as lithium, sodium, potassium, magnesium, and calcium, and alkaline earth metals.

Specific examples of the monovalent or polyvalent metal alkoxide include sodium alkoxide. One or a combination of two or more of these metal alkoxides may be contained in the glycidyl ethers.

Specific examples of glycidyl ethers used as the epoxy group-containing compound (b2) include sorbitol polyglycidyl ether, sorbitan polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, Glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, 2,2-bis (4 '-Glycidyloxyphenyl) propane and the like.

The aqueous dispersion composition may contain the glycidyl ester and the glycidyl ether as the epoxy group-containing compound (b2) either alone or in combination of two or more.

The epoxy group-containing compound (b2) reacts with the carboxyl group of the ionomer resin (b1) by heating to form a coating film having excellent adhesion to the curable resin layer (C) described below. In particular, compounds containing polyepoxy groups of ethylene and diglycidyl ethers such as polyethylene glycol diglycidyl ether are preferred.

The epoxy group-containing compound (b2)
Is preferably a water-soluble or dispersion-forming one in that the aqueous dispersion composition can be easily prepared, and particularly preferably a water-soluble one having a water solubility of 25% or more. In the present invention, the water solubility refers to the ratio of the amount of the epoxy group-containing compound (b2) actually dissolved in water when the epoxy group-containing compound (b2) is mixed with water at 25 ° C. That is, at a certain temperature T, the epoxy group-containing compound (b2) A ₁ g
Is dissolved in water, when A ₂ g of the insoluble portion of the epoxy group-containing compound (b2) remains, the water solubility of the epoxy group-containing compound (b2) at the temperature T is [(A ₁ −A ₂ ) / A
₁ ] × 100 (%). For example, when 90 g of water is mixed with 10 g of the epoxy group-containing compound (b2), and when 3 g of the insoluble epoxy group-containing compound (b2) remains, the water solubility becomes 70%.

Further, the epoxy group-containing compound (b)
The viscosity of 2) is 5 to 30,000 cps at 25 ° C.,
It is preferably in the range of 10 to 20,000 cps.

In the present invention, the epoxy group-containing compound (b2) usually has an epoxy equivalent of 80 to 2500 g,
In particular, those in the range of 120 to 2000 g are used. In the present invention, the epoxy equivalent refers to an epoxy group 1
It means the number of grams of the epoxy group-containing compound per gram equivalent. For example, when an epoxy group-containing compound having a molecular weight of 100 has one epoxy group in one molecule, the epoxy equivalent of the epoxy group-containing compound is 100. When the epoxy group-containing compound having a molecular weight of 100 has two epoxy groups in one molecule, the epoxy equivalent of the epoxy group-containing compound is 50.

The aqueous dispersion composition can be prepared, for example, by dissolving the epoxy group-containing compound (b2) in the aqueous dispersion of the ionomer resin (b1) or by adding the epoxy group to the aqueous dispersion of the ionomer resin (b1). The method can be performed according to a method in which an aqueous solution of the compound (b2) is mixed, a method in which a mixture of the ionomer resin (b1) and the epoxy group-containing compound (b2), and water are melted by heating and emulsified at once.

The aqueous dispersion of the ionomer resin (b1) is
It can be easily prepared and is usually 1 to 60
It can be prepared by a method in which the ionomer resin (b1) having a solid content of weight% is mixed, heated and melted at a temperature of 100 to 270 ° C., and dispersed.

The concentrations of the ionomer resin (b1) and the epoxy group-containing compound (b2) in the aqueous dispersion composition are not particularly limited, and are appropriately adjusted according to a coating method, a device used for coating, and the like. Usually, in the total amount of the ionomer resin (b1) and the epoxy group-containing compound (b2),
Suitably, it is 5 to 50% by weight, preferably 10 to 40% by weight.

Further, in the aqueous dispersion composition, the ionomer resin (b1) and the epoxy group-containing compound (b2)
Of the epoxy group-containing compound (b2) used
Anti-corrosive layer (B) which is excellent in water resistance and excellent in adhesion to top coat, by applying an aqueous dispersion composition to a metal substrate (A), although it depends on the molecular weight, epoxy equivalent, etc.
Is obtained, the epoxy group-containing compound (b2) is used in an amount of 0.05 to 100 parts by weight based on the ionomer resin (b1).
The proportion is preferably 50 parts by weight, more preferably 0.1 parts by weight.
The proportion is preferably from 30 to 30 parts by weight, particularly preferably from 0.5 to 10 parts by weight.

The aqueous dispersion composition comprises the ionomer resin (b1) and the epoxy group-containing compound (b
In addition to 2), if necessary, other components such as various resins and compounding agents may be contained in a range that does not impair the object of the present invention. Other components include, for example, a water-soluble amino resin for improving the strength of a coating film such as a water-soluble melamine resin and a water-soluble benzoguanamine resin; polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl methyl ether, polyethylene oxide, polyacrylamide, and polyacrylamide. An organic thickener such as acrylic acid, carboxymethylcellulose, methylcellulose and hydroxyethylcellulose for improving the stability of the aqueous dispersion composition and adjusting the viscosity; an inorganic thickener such as silicon dioxide, activated clay and bentonite; Surfactants for improving the stability of the aqueous dispersion composition such as nonionic surfactants and anionic surfactants; strontium chromate for improving the rust-preventing ability of the resulting rust-preventing layer (B); Water-soluble polyvalent metal salts; other rust inhibitors; An ultraviolet absorber; a heat stabilizer; a foaming agent; pigments such as titanium white, red iron oxide, phthalocyanine, carbon black, and permanent yellow; calcium carbonate, magnesium carbonate, barium carbonate, talc, aluminum hydroxide, calcium sulfate, kaolin, and mica. , Asbestos, mica, calcium silicate and the like.

The viscosity of the aqueous dispersion composition is from 30 to 30 from the viewpoint of coating workability for forming the rust preventive layer (B).
Suitably, it is about 1000 cps, preferably 50 to 800 cps.

In the laminate of the present invention, the formation of the rust-preventive layer (B) is carried out by applying the aqueous dispersion composition on a metal substrate (A), drying and curing. The application of the aqueous dispersion composition can be performed by a method such as spraying, curtain, flow coater, roll coater, brush coating, immersion and the like. After applying the aqueous dispersion composition, the composition may be air-dried, but is preferably baked. By heating at a baking temperature of 80 to 250 ° C. for 20 seconds to 10 minutes, a good rust prevention layer (B) is formed. In the step of forming the rust-proof layer (B), the aqueous dispersion composition contains almost no organic solvent or the like, and thus has an advantage that the working environment in the manufacturing process can be favorably maintained.

The thickness of the rust preventive layer (B) depends on the use of the laminate, the aqueous dispersion composition to be used, the type of curable resin for forming the curable resin layer (C) described below, and the curable resin. Layer (C)
The thickness is appropriately selected according to the thickness and the like, and is not particularly limited. Usually, after the application of the aqueous dispersion composition, a thickness of 0.5 to 20 μm, particularly 1 to 10 μm is preferable, in order to exhibit sufficient rust prevention without causing cracks in the coating when dried. .

The curable resin layer (C) of the laminate of the present invention comprises:
It is formed on the rust preventive layer (B) and is made of a heat-curable or room-temperature-curable curable resin. As the curable resin to be used, for example, a paint made of an acrylic resin, an acrylic-modified alkyd resin, an epoxy resin, a urethane resin, a melamine resin, a phthalic acid resin, an amino resin, a polyester resin, a vinyl chloride resin, and the like are exemplified.
Among these, a urethane resin, a melamine resin, or an acrylic resin is preferable as the curable resin layer (C) because the adhesiveness with the rustproof layer (B) is particularly excellent.

The curable resin contains coloring pigments such as titanium white and carbon black, extender pigments such as talc, metal pigments such as aluminum powder and copper powder, and rust-preventive pigments such as lead tin and lead sulfate. It may be. Further, it may contain a dispersant, a desiccant, a plasticizer, an antifoaming agent, a thickener, a stabilizer, an anti-skinning agent, a fungicide, a preservative, an antifreezing agent and the like.

In the laminate of the present invention, the thickness of the curable resin layer (C) is appropriately determined depending on the use of the laminate, the type of the curable resin to be used, and the like, and is not particularly limited. Usually, about 5 to 300 μm, particularly preferably 10 to 200 μm
It is about μm.

In the laminate of the present invention, the curable resin layer (C) can be formed by applying a curable resin on the rust preventive layer (B), heating and drying and curing. The drying time and temperature are appropriately adjusted according to the type of the curable resin to be applied, the thickness of the curable resin layer (C), and the like.
Usually, it takes about 5 to 120 minutes, especially about 20 to 80 minutes. In the case of a room temperature-curable curable resin, curing is completed in about one week. The drying temperature is usually in the range of room temperature to 200 ° C, and particularly in the range of 50 to 150 ° C.

The laminate of the present invention has a rustproof layer (B)
Since it has excellent water resistance and rust resistance, it can be suitably used as automobile parts, home appliances, building materials and the like. Further, since the coating of the laminate comprising the rust-proof layer (B) and the curable resin layer (C) is also excellent in drawability, surface protection, and heat sealability, the laminate of the present invention is: These characteristics can be utilized for various purposes.

[0046]

EXAMPLES The present invention will now be described specifically with reference to examples, but the present invention is not limited to these examples. In addition, in the following Examples, the evaluation of the coating film was performed by the following method.

Initial coating film adhesion (cross-cut test) According to the cross-cut test described in JIS K5400, a cross-cut test piece was prepared, and an adhesive tape (manufactured by Nichiban Co., Ltd.) After the adhesive tape was attached to the grid of the test piece, the adhesive tape was quickly pulled in the direction of 90 ° to peel it off, and the number of grids that were not peeled out of the grid 100 was counted, and (peeling). The value of (number of grids not performed) / 100 was used as an index of adhesion.

Adhesion after water resistance test: The test piece was immersed in a saline solution (3% by weight) at 40 ° C. for 200 hours, and then subjected to the above-mentioned cross-cut test.

Rust rate: After subjecting a 10 cm square test piece to the above-mentioned water resistance test, the area where rust was formed on the surface of the test piece was calculated as%.
Indicated by

Example 1 (Preparation of Aqueous Dispersion) A partially neutralized ethylene-methacrylic acid copolymer (MFR (190 ° C.) 0.8 g / 10
min, methacrylic acid content 15% by weight, neutralization degree 50
%, Neutralizing agent: sodium hydroxide) at 250 ° C. to prepare an ionomer resin melt. This ionomer resin melt was charged with 300 g of water and charged at 170 ° C.
Into a pressure-resistant homomixer with an internal volume of 1 l
Charged over about 2 hours while stirring at rpm. The mixture was cooled to room temperature with stirring for 30 minutes to obtain an aqueous dispersion of an ionomer resin. The resin concentration of the obtained aqueous dispersion of the ionomer resin was 25% by weight, and the viscosity was 600 cps.
(25 ° C.), the average particle size was 1 μm or less. Next, a 50% by weight aqueous solution of tetraethylene glycol diglycidyl ether was prepared, and 1.5 g of this aqueous solution was added to 100 g of an aqueous dispersion of an ionomer resin, followed by stirring to obtain an aqueous dispersion composition (hereinafter, referred to as “ Aqueous dispersion composition A ").

(Coating) The above aqueous dispersion A was applied to the surface of an aluminum foil (thickness: 200 μm) washed with n-hexane using a bar coater so as to have a dry film thickness of 6 μm. For 5 minutes at 150 ° C. to form a rustproof layer. Further, a urethane paint (Rethane PG60, manufactured by Kansai Paint Co., Ltd.) is applied on the rust preventive layer by spraying so as to have a thickness of 60 μm, and baked in an air oven at 80 ° C. for 30 minutes to cure. A coating sample was prepared by forming a conductive resin layer. With respect to this coating sample, the initial coating film adhesion (cross cut test) and the adhesion after the water resistance test were evaluated, and the rust generation rate was measured. Table 1 shows the results.

Example 2 A coating sample was prepared in the same manner as in Example 1 except that the paint was changed to a melamine paint (Nippon Paint Co., Ltd., Olga Select) and the baking conditions were changed to the conditions shown in Table 1. It was prepared, the initial coating film adhesion (cross-cut test) and the adhesion after the water resistance test were evaluated, and the rust generation rate was measured. Table 1 shows the results.

Example 3 An epoxy group-containing compound was
A coating sample was prepared in the same manner as in Example 1 except that 2-bis (4′-glycidyloxyphenyl) propane diglycidyl ether was used, and the initial coating film adhesion (cross-cut test) and the adhesion after the water resistance test were performed. The corrosion resistance was evaluated and the rust generation rate was measured. Table 1 shows the results.

Example 4 A 50% by weight aqueous solution of tetraethylene glycol diglycidyl ether was added to an aqueous dispersion of an ionomer resin.
A coating sample was prepared in the same manner as in Example 1 except that an aqueous dispersion was prepared by adding 15 g to 00 g, and using this aqueous dispersion, the initial coating film adhesion (cross-cut test) and water resistance The adhesion after the test was evaluated, and the rusting rate was measured. Table 1 shows the results.

(Comparative Example 1) A coating sample was prepared in the same manner as in Example 1 using only the aqueous dispersion of the ionomer resin prepared in Example 1, and the initial coating film adhesion (cross-cut test) and water resistance The adhesion after the test was evaluated. Table 1 shows the results.

Comparative Example 2 A coating sample was prepared in the same manner as in Example 1 except that only the 50% by weight aqueous solution of tetraethylene glycol diglycidyl ether prepared in Example 1 was applied. (Cross-cut test) and the adhesion after the water resistance test were evaluated. Table 1 shows the results.

(Example 5) A cold-rolled steel sheet (dull finish, thickness: 1 mm) was used instead of the aluminum foil.
A coating sample was prepared in the same manner as in Example 1, and the initial coating film adhesion (cross cut test) and the adhesion after the water resistance test were evaluated.
The rusting rate was measured. Table 1 shows the results.

Comparative Example 3 The procedure of Example 1 was repeated except that only the aqueous dispersion of the ionomer resin prepared in Example 1 was used, and a cold-rolled steel sheet (dull finish, thickness: 1 mm) was used instead of aluminum foil. A coating sample was prepared in the same manner as in Example 1, and the initial coating film adhesion (cross cut test) and the adhesion after the water resistance test were evaluated. Table 1 shows the results.

[0059]

[Table 1]

[0060]

The laminate of the present invention has a rust preventive layer having excellent water resistance and excellent adhesion to metals and the like, and a curable resin layer such as a paint formed on the rust preventive layer. It also has excellent layer adhesion.

Continuation of the front page (72) Inventor Eisaku Hirasawa 543-4 Kamo, Ichihara-shi, Chiba (56) References JP-A-58-91778 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , (DB name) B32B 15/08 B05D 7/14 B05D 7/24 B32B 27/08

Claims (3)

(57) [Claims] 1. A metal substrate (A), a rust-preventive layer (B) mainly containing a reaction product of an ionomer resin and an epoxy group-containing compound, and a metal substrate through the rust-preventive layer (B). (A) A laminate having a curable resin layer (C) laminated thereon. 2. The reaction product (B) of the ionomer resin and the epoxy group-containing compound is composed of 100 parts by weight of the ionomer resin and 0.05 to 50 of the water-soluble polyvalent epoxy group-containing compound.
2. The laminate according to claim 1, comprising an aqueous dispersion composition containing: 3. The laminate according to claim 1, wherein the curable resin layer (C) is made of at least one selected from a urethane resin, a melamine resin, and an acrylic resin.