JPH11269406A - Rustproofing coating composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a coating composition which can give a coating film excellent in adhesion even on a steel material having a surface with adherent foreign matter such as floating scale by incorporating a compound having at least one (meth)acryloyl group in the molecule with a fatty-acid-modified resin and a photosensitizer. SOLUTION: It is desirable that the fatty-acid-modified resin is at least one member selected among fatty-acid-modified alkyd resins, fatty-acid-modified epoxy resins, and fatty-acid-modified vinyl copolymers and has an oil length of 25-75%, and that the fatty acid residue has an unsaturated bond. It is desirable that the composition contains a resin not modified with a fatty acid, desirably, an acrylic resin. The composition has a content of the fatty-acid-modified resin of 5-80 wt.% in terms of solid content, and has an acid value of 20-80 mg as measured on solid content. The compound having an acryloyl groups is exemplified by an oligoester (meth)acrylate, urethane acrylate, epoxy acrylate, or glycidyl (meth)acrylate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a rust-preventive coating composition, and more particularly to a rust-preventing coating composition used for steel materials such as steel pipes and steel plates.

[0002]

2. Description of the Related Art Steel materials such as steel pipes and steel plates are coated with various rust preventives to prevent rust during storage after production, and are stored in that state until use. When used, the rust inhibitor is often removed by an alkali treatment or the like.

[0003] The surface of a steel material to which a rust preventive is applied generally has various foreign substances such as scales (including floating scales) and dust attached thereto, and general rust preventives (rust preventive oil, rust preventive varnish, etc.). ) Is applied to the surface of such a steel material, the rust inhibitor penetrates into these foreign substances, so that the adhesion is not greatly reduced. In order to harden immediately after application, a film is formed on these foreign substances, and as a result, the adhesion to the steel material surface is often poor.

As a means for preventing such poor adhesion, it is effective to incorporate a brushing step or a cleaning step on the surface of the steel material before coating. This is a negative factor in deployment.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to solve the above problem even if the surface of a steel material has a foreign matter such as a floating scale adhered thereto. The present invention provides a coating composition having good adhesiveness to the coating composition and excellent rust prevention.

[0006]

The present invention has the following features. (1) A rust-preventive coating composition comprising a compound having at least one (meth) acryloyl group in a molecule, a fatty acid-modified resin, and a photosensitizer. (2) The rust-preventive coating composition according to (1), wherein the fatty acid-modified resin is at least one selected from a fatty acid-modified alkyd resin, a fatty acid-modified epoxy resin, and a fatty acid-modified vinyl copolymer. (3) The above wherein the oil length of the fatty acid-modified resin is 25 to 70%.
The rust-preventive coating composition according to (1) or (2). (4) The rust preventive coating composition according to any one of the above (1) to (3), wherein the fatty acid residue of the fatty acid-modified resin is a fatty acid residue having an unsaturated bond. (5) The rust-preventive coating composition according to any one of the above (1) to (4), wherein the composition further contains a resin not modified with a fatty acid. (6) The rust preventive coating composition according to the above (5), wherein the resin not modified with a fatty acid is an acrylic resin. (7) The rust preventive coating composition according to any one of the above (1) to (6), wherein the content of the fatty acid-modified resin in the composition is 5 to 80% by weight in terms of solid content. (8) The acid value of the solid content in the composition is 20 mg or more and 200 mg or more.
The rust preventive coating composition according to any one of the above (1) to (7), which is: (9) The rust-preventive coating composition according to any one of the above (1) to (8), which is for steel materials.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The first component of the composition of the present invention is a compound having at least one (meth) acryloyl group in a molecule.
This compound undergoes a polymerization reaction involving its unsaturated bond due to ultraviolet irradiation and the action of a sensitizer, and is cured to form a coating film. As this compound, for example,
Are exemplified.

The reaction between polyol and (meth) acrylic acid
Oligoester (meth) acrylate obtained by the reaction The polyol used in the present invention includes, for example, ethylene glycol, propylene glycol, glycerin,
Examples include polyols such as pentaerythritol and trimethylolpropane. Furthermore, ethylene oxide, propylene oxide, ε-caprolactone, γ-butyrolactone, etc. to these polyols, alkylene oxide-modified or lactone-modified polyols obtained by addition reaction, or excessive amounts of these polyols and polybasic acid or Examples thereof include polyester polyols and polyether polyols having a terminal hydroxyl group obtained by condensation with an acid anhydride.

The above-mentioned polybasic acid or its acid anhydride is not particularly restricted but includes, for example, phthalic acid, isophthalic acid, adipic acid, hexahydrophthalic acid, maleic acid,
Examples thereof include fumaric acid, tetrahydrophthalic acid, and acid anhydrides thereof.

Examples of the polyol include those obtained by reacting a compound having at least two epoxy groups or glycidyl groups in a molecule with a monovalent acid or a monovalent amine. The compound having at least two epoxy groups or glycidyl groups in the molecule is not particularly limited. For example, a glycidyl ether type compound containing bisphenol A, bisphenol F, 2,6-xylenol, brominated bisphenol A, phenol novolak, etc. Epoxy resin; glycidyl ester type epoxy resin having dimer acid or the like; glycidyl ester type epoxy resin having aromatic or heterocyclic amine or the like; alicyclic epoxy resin; acrylic resin having an epoxy group or glycidyl group. Can be.

The monovalent acid is not particularly limited.
For example, acetic acid, propionic acid, benzoic acid, lauric acid,
Examples thereof include stearic acid, butyric acid, and (meth) acrylic acid. The monovalent amine is not particularly limited and includes, for example, monoethylamine, diethylamine, triethylamine, isopropylamine, diisopropylamine, mono-n-butylamine, di-n-butylamine, tri-n-butylamine, mono-2-amine. Examples include ethylhexylamine, monobenzylamine, piperidine, morpholine, n-methylmorpholine, n-ethylmorpholine, and cetylmorpholine.

A compound having a terminal isocyanato group in a molecule
The compound has a hydroxyl group and a (meth) acryloyl group
As the compound having a terminal isocyanato group in the urethane acrylate molecule obtained by adding the compound,
For example, polyisocyanate or those obtained by reacting polyisocyanate with the polyol exemplified above can be used. Among them, when a polyol obtained by reacting a compound having at least two epoxy groups or glycidyl groups in the molecule exemplified above with a monovalent acid or a monovalent amine is used, For example, a compound having one isocyanato group in one molecule obtained by reacting a compound having one hydroxyl group and (meth) acryloyl group in the molecule with polyisocyanate in advance, and a compound having at least two isocyanates in the molecule By reacting a polyol obtained by reacting a compound having an epoxy group or a glycidyl group with a monovalent acid or a monovalent amine, a urethane-modified epoxy acrylate having an ester bond and a urethane bond can be obtained.

The polyisocyanate may be, for example, any of aliphatic, alicyclic, aromatic, and aromatic-aliphatic types. For example, tolylene diisocyanate,
Diisocyanates such as 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate; examples thereof include a nurate, buret, and adduct of these diisocyanates.

Examples of the compound having a hydroxyl group and a (meth) acryloyl group include pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, epoxy (meth) acrylate and (meth) acrylic acid-2- Hydroxyethyl,
Glycerol di (meth) acrylate, and alkylene oxide-modified or lactone-modified compounds obtained by adding ethylene oxide, propylene oxide, ε-caprolactone, γ-butyrolactone, and the like thereto, and the like. A compound obtained by adding a polyisocyanate to a compound can also be used.

At least two epoxy groups are present in the molecule.
Or a compound having a glycidyl group and (meth) acrylic acid
Examples of the compound having at least two epoxy groups or glycidyl groups in the molecule of epoxy acrylate obtained by reacting with the above include compounds having at least two epoxy groups or glycidyl groups in the molecule exemplified above. Can be mentioned.

At least two carboxyls in the molecule
Having an oxirane group and unsaturated monomer having an oxirane group
The compound having at least two carboxyl groups in the (meth) acrylate molecule obtained by reacting with the above is not particularly limited, and examples thereof include the polybasic acids exemplified above. As the unsaturated monomer having an oxirane group, glycidylyl (meth)
Acrylate, methylglycidylyl (meth) acrylate and the like can be mentioned.

In the present invention, depending on the composition, tackiness may remain, which is not preferable. As a means for preventing tackiness, a method for enhancing curability is advantageous. For this purpose, among the compounds having at least one (meth) acryloyl group in the above-mentioned molecule, at least three compounds in the molecule are preferred. It is desirable to use a compound having a (meth) acryloyl group.

Examples of the compound having at least three (meth) acryloyl groups in the molecule include the following a, a, b, a and the like.

A ) having three or more hydroxyl groups in the molecule
Esterified product of compound and (meth) acrylic acid Examples of the compound having three or more hydroxyl groups in the molecule include pentaerythritol, dipentaerythritol, trimethylolpropane, trimethylolethane, ditrimethylolpropane, glycerin, Examples thereof include glycerin and the like, and further include alkylene oxide-modified or lactone-modified polyols obtained by adding ethylene oxide, propylene oxide, ε-caprolactone, γ-butyrolactone, and the like thereto.

A ) 3 or more terminal isocyanates in the molecule
Hydroxyl group and (meth) acryloyl
Urethane modification obtained by adding a compound having an yl group
Examples of the compound having three or more terminal isocyanato groups in the molecule of the (meth) acrylate compound include those obtained by reacting a polyol having three or more hydroxyl groups in the molecule with a polyisocyanate compound. Examples of the polyol having three or more hydroxyl groups in the molecule include polyols of glycerin, pentaerythritol, and trimethylolpropane; obtained by adding ethylene oxide, propylene oxide, ε-caprolactone, γ-butyrolactone, etc. Alkylene oxide-modified or lactone-modified polyols; polyester polyols having terminal hydroxyl groups obtained by condensing an excess of these polyols with a polybasic acid or an acid anhydride thereof.

Examples of the polyisocyanate compound include aliphatic, alicyclic, aromatic and aromatic compounds.
Any aliphatic polyisocyanate may be used, and examples thereof include tolylene diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate. Further, a nurate of these diisocyanates,
Bullet bodies, adduct bodies and the like are also included.

The compounds having a hydroxyl group and a (meth) acryloyl group include, for example, the compounds exemplified above.

B) excess polyol and polybasic acid or
Having a terminal hydroxyl group obtained by condensing with the acid anhydride
Polyester polyols, polyether polyols and polyester polyols
3 in the molecule obtained by reacting with lysocyanate
The compounds having a terminal isocyanato group described above include a hydroxyl group and
And a compound having a (meth) acryloyl group
Examples of the compound having three or more terminal isocyanato groups in the molecule of the obtained urethane-modified (meth) acrylate compound include , for example, the compounds exemplified in the above a). Examples of the polyol include the polyols exemplified above. Examples of the polybasic acid or an acid anhydride thereof include the compounds exemplified above.

A ) three or more epoxy groups or
Is a compound having a glycidyl group and (meth) acrylic acid
Examples of the compound to the ester in the molecule having three or more epoxy groups or glycidyl groups, for example, glycerol triglycidyl ether, trimethylolpropane triglycidyl ether, sorbitol tetraglycidyl ether, sorbitol penta glycidyl ether, sorbitan tetraglycidyl ether , Sorbitan pentaglycidyl ether, triglycerol tetraglycidyl ether, tetraglycerol tetraglycidyl ether,
Examples thereof include pentaglycerol tetraglycidyl ether, triglycerol pentaglycidyl ether, tetraglycerol pentaglycidyl ether, pentaglycerol pentaglycidyl ether, pentaerythritol tetraglycidyl ether, and triglycidyl isocyanurate.

Further, among the o-cresol novolak type epoxy resins, compounds having three or more glycidyl groups may be mentioned.
N-220L (Sumitomo Chemical Industries, Ltd.), Sumiepoxy ES
CN-220N (manufactured by Sumitomo Chemical Co., Ltd.) and the like.

In the above molecule, at least three (meth)
Among the compounds having an acryloyl group, an esterified product of the compound having three or more hydroxyl groups in the molecule of a) and (meth) acrylic acid is preferred, and particularly, pentaerythritol, dipentaerythritol and trimethylolpropane are preferred. Esterified products of any of them and (meth) acrylic acid are preferred.

The composition of the present invention may further contain other compounds having an unsaturated bond, such as diallyl fumarate and triallyl isocyanurate, if necessary.

In the above molecule, at least one (meth)
The compound having an acryloyl group in the composition of the present invention is preferably 20 to 80% by weight, more preferably 20 to 60% by weight.
% By weight. If the content is less than 20% by weight, the resulting coating film may have poor gloss and tackiness, and if it exceeds 80% by weight, the adhesion may be reduced.

The second component of the composition of the present invention is a fatty acid-modified resin. In the present invention, the fatty acid-modified resin refers to a resin modified with a fat or oil or a fatty acid and having a fatty acid residue in a side chain. By containing the resin, the composition of the present invention, even in the case of a steel material or the like to which a foreign matter such as a floating scale or dust adheres to the surface, the adhesion between the steel material and the coating film becomes good, and the coating film peels off. Is prevented. Examples of the fatty acid-modified resin include the following resins (1) to (3).

(1) Fatty acid-modified alkyd resin The fatty acid-modified alkyd resin (1) used in the present invention is not particularly limited. For example, in addition to a polyhydric alcohol and a polybasic acid or an acid anhydride thereof, Examples of the modifier include those which can be obtained by using fats and oils or fatty acids.

The polyhydric alcohol is not particularly restricted but includes, for example, the polyols exemplified as the first component. The polybasic acid or acid anhydride is not particularly limited, and examples thereof include the compounds exemplified as the first component.

The fats and oils or fatty acids are not particularly limited, and include, for example, linseed oil, tall oil, sardine oil, cutting oil,
Fats and oils such as dehydrated castor oil, safflower oil, soybean oil, sesame oil, cottonseed oil, castor oil, coconut oil, and fatty acids obtained therefrom can be mentioned. The above fats and oils or fatty acids preferably have an unsaturated bond from the viewpoint of the oxidative polymerization of the composition and the adhesion to steel, and for example, use fats and oils or fatty acids having an iodine value of 120 to 210. It is particularly preferred to do so. As such fats or oils, specifically, linseed oil, tall oil, soybean oil, sesame oil, rapeseed oil, cutting oil, dehydrated castor oil, safflower oil,
Fats and oils such as cottonseed oil and fatty acids obtained therefrom are exemplified. These may be used alone or in combination of two or more.

The above fatty acid-modified alkyd resin (1) is produced, for example, by the following method. When using fats and oils as a modifier, the following two-stage reaction is usually performed. First, all or a part of the fat or oil and the polyhydric alcohol are mixed, and a transesterification reaction is performed at 200 to 260 ° C. using an oxide or hydroxide such as lead or lithium as a catalyst. It is produced by adding a basic acid and conducting an esterification reaction at 180 to 240 ° C. During the esterification reaction, an esterification catalyst may be added if necessary. When a fatty acid is used as a modifier, a one-step reaction is usually performed. That is, it is produced by mixing a polybasic acid, a polyhydric alcohol and a fatty acid, and performing an esterification reaction at 180 ° C. to 240 ° C. If necessary, an esterification catalyst may be added. The solid content of the obtained resin is adjusted by a solvent or a compound having at least one (meth) acryloyl group in a molecule.

The number average molecular weight of the fatty acid-modified alkyd resin (1) is preferably from 1,000 to 8,000. If the molecular weight is less than 1000, the resulting coating film may have a sticky feeling, while if it exceeds 8000, the adhesion of the coating film to a steel material to which foreign matter such as a floating scale has adhered may be poor.

Specific examples of such a fatty acid-modified alkyd resin include, for example, coconut oil-modified alkyd resin:
Veccosol 1323-60-EL (manufactured by Dainippon Ink and Chemicals, oil length 28%); as a tall oil-modified alkyd resin, R-1730 (manufactured by Nippon Paint Co., oil length 39)
%), Veccosol ET-6502-60 (Dai Nippon Ink and Chemicals, oil length 65%); Veccosol ES-6505-70 (Dai Nippon Ink and Chemicals, oil length 65% as a soybean oil-modified alkyd resin) ), Beccosol OD
-E-198-50 (manufactured by Dainippon Ink and Chemicals, oil length 28%), Veccosol ES-4020-55 (manufactured by Dainippon Ink and Chemicals, oil length 40%), Veccosol P-
470-70 (made by Dainippon Ink and Chemicals, oil length 65
%); As a safflower oil-modified alkyd resin, Veccosol J-557 (manufactured by Dainippon Ink and Chemicals, oil length 51)
%); As a linseed oil-modified alkyd resin, Veccosol 45-163 (manufactured by Dainippon Ink and Chemicals, oil length 28)
%), Beccosol EL-4501-50 (manufactured by Dainippon Ink and Chemicals, Inc., oil length 45%), Beccosol EL-6
501-70 (made by Dainippon Ink and Chemicals, oil length 65
%) And the like. In the present specification, “oil length” refers to the weight percentage of the fatty acid-modified resin in terms of the amount of the fatty acid residue in the fatty acid-modified resin converted to the weight of the fatty acid triglyceride.

(2) Fatty acid-modified epoxy resin The fatty acid-modified epoxy resin (2) used in the present invention is obtained by modifying a polymer having an epoxy group with an oil or a fatty acid. The polymer having an epoxy group is not particularly limited, and examples thereof include bisphenol-type epoxy resins based on bisphenol A, bisphenol B, bisphenol F, and halogen-substituted products thereof; and aliphatic ether-type resins such as ethylene glycol diglycidyl ether. Epoxy resins and the like can be mentioned.

As the polymer having an epoxy group, a commercially available polymer can also be used. For example,
Epicoat 1001, 1004 (manufactured by Shell Chemical Co., Ltd.); Epototo YD-012, 017, 019, 020 (manufactured by Toto Kasei); Phenotote YP-50, 50S, YDF
-2004, ZX-1356, 1395 (manufactured by Toto Kasei); Denacol EX-212, 301, 411, 61
6 (manufactured by Nagase Kasei Co., Ltd.). These may be used alone or in combination of two or more.

Examples of the fats and oils or fatty acids include those similar to those exemplified for the fatty acid-modified alkyd resin (1).

The number average molecular weight of the fatty acid-modified epoxy resin (2) is preferably from 2,000 to 6,000. If the molecular weight is less than 2,000, the resulting coating film may have a sticky feeling, while if it exceeds 6,000, the adhesion of the coating film to a steel material to which foreign matter such as a floating scale has adhered may be poor.

The above fatty acid-modified epoxy resin (2) is prepared by mixing an epoxy resin and a fatty acid,
It is obtained by a dehydration reaction at ℃. The reaction temperature at this time may be about 160 ° C. when only the epoxy group in the epoxy resin is esterified by ring opening, but is within the above range when the hydroxyl group in the epoxy resin is also esterified. Is preferred.

Specific examples of such fatty acid-modified epoxy resin (2) include ET-4 (Nippon Paint Co., Ltd., oil length 40%) and EPS-1000 (Nippon Paint Co., Ltd., oil length 50). %) And the like.

(3) Fatty acid-modified vinyl copolymer (3) Fatty acid-modified vinyl copolymer used in the present invention
Is, for example, a fatty acid-modified unsaturated monomer (A) and α, β
A glycidyl ester of a fatty acid (a copolymer obtained by copolymerizing the ethylenically unsaturated monomer (B) or in advance by copolymerizing the component (B) with the ethylenically unsaturated carboxylic acid (C) component; D).

Examples of the fatty acid-modified unsaturated monomer (A) used in the fatty acid-modified vinyl copolymer (3) include the following compounds (a) to (e).

(A) A monomer obtained by reacting an oxirane group-containing unsaturated monomer with a fatty acid (for example, Japanese Patent No.
003944). Examples of the oxirane group-containing unsaturated monomer include glycidyl methacrylate and methyl glycidyl methacrylate. Examples of the fatty acid include those similar to those exemplified for the fatty acid-modified alkyd resin (1).

(B) Monomers obtained by reacting a hydroxyl group-containing unsaturated monomer with a fatty acid (for example, see JP-A-56-58).
No. 63). As the hydroxyl group-containing unsaturated monomer,
For example, 2-hydroxy methacrylate, 2-hydroxypropyl acrylate and the like are exemplified. Examples of the fatty acid include those similar to those exemplified for the fatty acid-modified alkyd resin (1).

(C) A monomer obtained by adding an isocyanate compound to the secondary hydroxyl group of the monomer obtained in (a) (see, for example, JP-A-55-92773). Examples of the isocyanate compound include phenyl isocyanate.

(D) A monomer obtained by reacting an organic acid, an organic acid anhydride, or an organic acid chloride with the secondary hydroxyl group of the monomer obtained in the above (a) (for example, see
-98266 gazette). As the organic acid, for example,
Benzoic acid, stearic acid and the like can be mentioned, examples of the organic acid anhydride include, for example, acetic anhydride and butyric anhydride, and examples of the organic acid chloride include, for example, acetyl chloride.

(E) a monomer containing at least one urethane bond (—NH—COO—), a fatty acid residue and one ethylenically unsaturated bond in the molecule, for example, an unsaturated monomer containing an isocyanato group; Monomer obtained by reacting a monomer and a compound having a hydroxyl group and a fatty acid residue, or
A monomer obtained by reacting a hydroxyl group-containing acrylic monomer with a compound having an isocyanato group and a fatty acid residue (see, for example, Japanese Patent Application No. 59-252754). Examples of the isocyanato group-containing unsaturated monomer include isocyanatoethyl (meth) acrylate. Examples of the compound having a hydroxyl group and a fatty acid residue include a product obtained by reacting a monoepoxy compound with a fatty acid. And the like. Examples of the hydroxyl group-containing acrylic monomer include, for example, 2-hydroxyethyl methacrylate. Examples of the compound having an isocyanate group and a fatty acid residue include, for example, a compound having a hydroxyl group and a fatty acid residue and a diisocyanate compound. A product obtained by the reaction is mentioned.

The α, β-ethylenically unsaturated monomer (B) used in the fatty acid-modified vinyl copolymer (3) is the above-mentioned (A)
It is a compound other than the component and having an α, β-ethylenically unsaturated bond. Specifically, the following (f) to (i) are representatively exemplified.

(F) Ester of acrylic acid or methacrylic acid: for example, methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, hexyl acrylate, octyl acrylate,
Lauryl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, hexyl methacrylate,
Octyl methacrylate, C ₁ -C ₁₀ alkyl esters of acrylic acid or methacrylic acid lauryl methacrylate: glycidyl acrylate, glycidyl methacrylate; allyl acrylate, C ₂ -C ₆ alkenyl esters of acrylic or methacrylic acid and allyl methacrylate: hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxyethyl methacrylate, hydroxyalkyl esters of C ₃ -C ₁₈ acrylic acid or methacrylic acid such as hydroxyethyl methacrylate: allyl oxyethyl acrylate, acrylic acid or methacrylic acid and allyl methacrylate alkenyloxyalkyl esters of C ₃ -C _18.

(G) Vinyl aromatic compounds: for example, styrene, α-methylstyrene, vinyltoluene, p-chlorostyrene. (h) Polyolefin compounds: for example, butadiene, isobutane, chloroprene. (i) Others: acrylonitrile, methacrylonitrile,
Methyl isopropenyl ketone: vinyl acetate, veoba monomer (shell chemical products), vinyl propionate, vinyl pivalate, etc.

These α, β-ethylenically unsaturated monomers
(B) is appropriately selected according to the desired physical properties, and may be used alone or in combination of two or more.

The production of the fatty acid-modified vinyl copolymer (3) is carried out, for example, by preparing the fatty acid-modified unsaturated monomer (A) and α, β
-It can be carried out by copolymerizing the ethylenically unsaturated monomers (B) with one another. The copolymer can be produced according to a method known per se for producing an ethylene copolymer, for example, using a solution polymerization method.

The mixing ratio of the above two components in the copolymerization can be selected as appropriate, but the fatty acid-modified vinyl copolymer can be selected.
(3) Among them, the fatty acid-modified unsaturated monomer (A) is preferably
The α, β-ethylenically unsaturated monomer (B) is preferably blended at a ratio of 30 to 60% by weight.

Also, the fatty acid-modified vinyl copolymer (3)
Is to react fatty acid glycidyl ester (D) with a copolymer obtained by copolymerizing α, β-ethylenically unsaturated monomer (B) and ethylenically unsaturated carboxylic acid (C). Can also be obtained by

The ethylenically unsaturated carboxylic acid (C) used herein is an unsaturated fatty acid of the type having an addition polymerizable double bond between a carbon atom to which a carboxyl group is bonded and a carbon atom adjacent thereto. Monomers or polycarboxylic acids containing 3 to 8, especially 3 to 5 carbon atoms, and having one or two carboxyl groups are suitable, and are typically represented by the following general formula (I) or ( II) is exemplified.

[0057]

Embedded image

(Wherein, R ¹ represents a hydrogen atom or a lower alkyl group, R ² represents a hydrogen atom, a lower alkyl group or a carboxyl group, and R ³ represents a hydrogen atom, a lower alkyl group or a carboxy lower alkyl group. .)

[0059]

Embedded image

(Wherein m is an integer of 2 to 8, and R ⁴ represents a hydrogen atom or a methyl group).

In the above formula (I), the lower alkyl group is preferably one having 4 or less carbon atoms, particularly preferably a methyl group. The carboxy lower alkyl group is preferably a group having 3 or less carbon atoms, particularly preferably a carboxyethyl group.

Examples of such ethylenically unsaturated carboxylic acids (C) include acrylic acid, methacrylic acid, crotonic acid,
Itaconic acid, maleic acid, maleic anhydride, fumaric acid,
Examples thereof include 2-carboxyethyl (meth) acrylate and 2-carboxypropyl (meth) acrylate, which can be used alone or in combination of two or more.

The glycidyl ester of a fatty acid (D) used herein is, for example, one represented by the following general formula (III).

[0064]

Embedded image

(Wherein, R ⁵ represents an aliphatic hydrocarbon group)

Specific examples thereof include glycidyl ester of soybean oil fatty acid, glycidyl ester of safflower oil, and glycidyl ester of linseed oil.

As still another method, an α, β-ethylenically unsaturated monomer (B) and an ethylenically unsaturated carboxylic acid
(C) a copolymer having a hydroxyalkyl ester as an essential monomer, and an addition reaction of the resulting polymer with a compound having an isocyanate group and a fatty acid residue. Polymer (3) can be produced.

The compound having an isocyanate group and a fatty acid residue can be prepared by reacting a diisocyanate compound with a reactive product of a fatty acid and a 1,2-epoxy compound or a polyhydric alcohol, or a compound having a hydroxyl group and a fatty acid residue. It can be manufactured (for example, Japanese Patent Application No.
252754).

The fatty acid-modified vinyl copolymer (3) contains 50
It preferably has a number average molecular weight of 0 to 100,000, particularly 1000 to 60000. Number average molecular weight is 500
If the amount is less than the above, blocking resistance, coating film hardness, water resistance, etc. of the obtained coating film may be inferior. On the other hand, if it exceeds 100,000, the viscosity may increase and the production may be difficult.

Specific examples of the fatty acid-modified vinyl copolymer (3) include ACS-1056 (Nippon Paint Co., Ltd., oil length 33%).

Examples of the fatty acid-modified resin include the above-mentioned fatty acid-modified alkyd resin (1), fatty acid-modified epoxy resin (2),
In addition to the fatty acid-modified vinyl resin (3), a resin obtained by further modifying a fatty acid-modified alkyd resin with acryl is exemplified.

The oil length of the fatty acid-modified resin is preferably 25 to 75%, more preferably 32 to 42%. If the oil length is less than 25%, the adhesion of the coating to the steel material to which foreign matter such as a floating scale has adhered may be inferior. On the other hand, if the oil length exceeds 75%, the resulting coating may have a sticky feeling. There is.

The above fatty acid-modified resin is contained in the composition of the present invention in an amount of preferably 5 to 80% by weight, more preferably 40 to 80% by weight in terms of solid content. This content is 8
If it exceeds 0% by weight, the resulting coating film may remain sticky, while if it is less than 5% by weight, the adhesion of the coating film to a steel material to which foreign matter such as a floating scale has adhered may be poor. .

The third component of the composition of the present invention is a sensitizer. This sensitizer contains at least one (meth)
It acts as an initiator of a photopolymerization reaction of a compound having an acryloyl group. The sensitizer is not particularly limited. For example, benzoin methyl ether, benzoin ethyl ether, benzoin isobutyl ether, benzoin isopropyl ether, benzoin, α-methylbenzoin, benzoin-n-butyl ether, 2-ethylanthraquinone, 2-t- Butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone, 2-aminoanthraquinone, benzophenone, p-chlorobenzophenone, p-dimethylaminobenzophenone, benzophenone methyl ether, methylbenzophenone,
4,4-dichlorobenzophenone, 4,4-bisdiethylaminobenzophenone, diphenyl sulfide, tetramethylthiuram disulfide, 2,4-dimethylthioxanthone, 2,4-diisopropylthioxanthone,
2,4-diethylthioxanthone, 2-chlorothioxanthone, 2-isopropylthioxanthone, 2,2-dimethoxy-2-phenylacetophenone, α, α-dichloro-4-phenoxyacetone, p-tert-butyltrichloroacetophenone, p-tert -Butyldichloroacetophenone, 2,2-diethoxyacetophenone, p-dimethylaminoacetophenone, hydroxycyclohexylphenyl ketone, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropane-1
-One, 2,2-dimethoxy-1,2-diphenylethan-1-one, 2,4,6-trimethylbenzoindiphenylphosphine oxide, 2-methyl-1- [4-
(Methylthio) phenyl] -2-morpholinopropan-1-one, 4- (2-acryloxy) oxyethoxy-phenyl-2-hydroxy-2-propyl ketone, 4
-(2-hydroxy) phenyl- (2-hydroxy-2
-Propyl) ketone, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylphenylphosphine oxide and the like. Of these, 2,
4-dimethylthioxanthone, 2,4-diisopropylthioxanthone, 2,4-diethylthioxanthone,
-Chlorothioxanthone, 2-isopropylthioxanthone, hydroxycyclohexyl phenyl ketone, 1-
(4-Isopropylphenyl) -2-hydroxy-2-
Methylpropan-1-one, 2,2-dimethoxy-1,
2-diphenylethan-1-one has curability, adhesion,
It is preferable because it has excellent heat resistance. In the present invention, one or more of these can be used in combination.

The sensitizer is preferably used in an amount of 2 to 100 parts by weight in total of the first component and the second component.
15 parts by weight, more preferably 3 to 10 parts by weight. If the content is less than 2 parts by weight, the first component, a compound having at least one (meth) acryloyl group in a molecule, may not be sufficiently cured by ultraviolet irradiation. Conversely, if the amount exceeds 15 parts by weight, the effect is not changed, but it is economically disadvantageous.

The composition of the present invention preferably further contains a resin not modified with a fatty acid. Specific examples of the resin include the following (i) to (iii).
These can be used alone or in combination of two or more.

(I) Solvent-soluble resins such as acrylic resins, polyester resins, polyvinyl butyral resins, ethylene-vinyl acetate copolymer resins, vinyl acetate resins, vinyl chloride resins and polyamide resins.

(Ii) An unsaturated polyester resin obtained by using maleic anhydride as one component of a polybasic acid when polymerizing a polybasic acid or its anhydride with a polyhydric alcohol. Examples of the polybasic acid, its anhydride and polyhydric alcohol include those described for the compound having at least one (meth) acryloyl group in the molecule.

(Iii) An unsaturated acrylic resin obtained by reacting an acrylic polymer obtained by polymerizing an esterified product of acrylic acid or methacrylic acid having a hydroxyl group as one component with maleic anhydride and a compound having an epoxy group. Examples of the esterified product of acrylic acid or methacrylic acid having the hydroxyl group include those described for the compound having at least one (meth) acryloyl group in the molecule. Examples of the compound having an epoxy group include butyl glycidyl ether, phenyl glycidyl ether, and allyl glycidyl ether.

The resin not modified with the above fatty acid is
It is preferable that the number average molecular weight is 3000 or more. If the number average molecular weight is less than 3,000, the resulting coating film may remain sticky.

The resin not modified with the above fatty acid is
Preferably, 10 to 60 parts by weight is blended with respect to 100 parts by weight of the total of the first to third components. If the amount exceeds 60 parts by weight, the resulting coating film may remain sticky.

The acid value of the composition of the present invention is preferably 20 mg from the viewpoint of easy removal of the coating film by alkali treatment.
Not less than 200 mg. If the acid value is less than 20 mg, it may be difficult to remove the coating film formed on the surface of the steel material by alkali treatment at the time of use. Conversely, if it exceeds 200 mg, the corrosion resistance of the coating film may decrease. The acid value is the amount of KOH required to neutralize 1 g (mg)
Say.

In order to adjust the acid value of the composition of the present invention to the above-mentioned range, fatty acid-modified resins such as fatty acid-modified alkyd resins, fatty acid-modified epoxy resins, and fatty acid-modified vinyl copolymers, and those not modified with fatty acids. What is necessary is just to adjust the compounding quantity of resin etc.

The composition of the present invention may further contain a surface conditioner. The surface conditioner is not particularly limited, and examples thereof include a fluorine-based additive and a cellulose-based additive. The amount of the surface conditioner can be appropriately adjusted as needed.

An alcohol-based solvent, an ester-based solvent, an aromatic hydrocarbon-based solvent, or the like may be further added to the composition of the present invention to dilute the composition of the present invention to facilitate coating.

The composition of the present invention can be applied to steel, for example, by the following method. First, for example, when the steel material is in the form of a pipe, the coating liquid of the composition of the present invention is supplied to the outer peripheral surface thereof while being conveyed in the longitudinal direction. As a means for supplying the coating liquid to the outer peripheral surface of the pipe being transported in the longitudinal direction, the coating liquid is discharged from the discharge port toward the pipe under gravity or under pressure, but the application of ironing means by ironing means In order to avoid this, it is desirable to supply the coating liquid evenly to the outer peripheral surface of the pipe. For this purpose, it is preferable to adjust the opening degree of the discharge port or to provide a plurality of discharge ports. When the coating liquid is supplied in a curtain shape or a shower shape to the outer peripheral surface of the pipe by such a supply means, the contamination of the working environment due to the scattering of the coating liquid can be prevented as compared with the spray supply of the coating liquid by a normal spray method,
Further, the spray method has an advantage that a coating liquid having a viscosity in an area where coating is difficult can be used.

After the coating liquid is supplied to the outer peripheral surface of the pipe, the paint is evenly applied to the entire outer peripheral surface by ironing means while transporting the pipe in its length direction. The ironing means may be an inelastic body having an opening similar in shape to the cross section of the pipe and having a larger dimension, or an elastic body having an opening having the same shape as or similar to the cross section of the pipe and having a smaller dimension. This is done by using the body. The former can adjust the thickness of the coating film by the thickness of the opening and the gap between the opening and the outer peripheral surface of the tube. In the latter, the thickness of the coating film can be adjusted by the material of the elastic body, the thickness of the opening, the dimensional ratio between the opening and the outer shape of the tube, and the like. The viscosity of the coating liquid used, the pipe transfer speed, and the like also become factors in adjusting the film thickness. In this way, a coating film having a desired film thickness can be obtained by the ironing means.

The pipe uniformly applied to the outer peripheral surface by the above-mentioned ironing means is forcibly dried, if necessary, to remove the solvent, and then cured by ultraviolet irradiation while transporting the pipe in its length direction. The standard thickness is preferably 5 to 20 μm in order to secure corrosion resistance. In addition, a known high-pressure mercury lamp, metal halide lamp, or the like may be used as the ultraviolet irradiation source. The amount of ultraviolet irradiation is about 500 to 5000 mJ. In order to uniformly irradiate the coating film with ultraviolet rays, it is preferable that the ultraviolet irradiation sources are evenly arranged in the circumferential direction of the pipe.

When coated using the coating composition of the present invention, even a steel material to which foreign matter such as scale and dust adheres,
Adhesion with the steel material is good, the coating does not peel off, and a coating film having good rust prevention can be obtained. Therefore, for example, it is suitably used as a paint for rust prevention of steel materials such as steel pipes and steel plates.

[0090]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to examples, but the present invention is not limited to these examples. Hereinafter, a method for evaluating a coating film obtained by using the coating composition of the present invention will be described. 1. Adhesion After forming the coating, the surface of the coating on the steel plate is
It was evaluated by counting the number of grids remaining without being peeled by cutting the grid into zero 2 mm-wide grids, applying a cellophane adhesive tape (manufactured by Nichiban Co., Ltd.) from above, and rapidly peeling off. 100/100 remained, ○, 99/1
Those that remained from 00 to 91/100 were rated as Δ, and those that were 90/100 or less were rated as x. 2. Adhesiveness Measured according to JIS K 5400 6.5.

Examples 1 to 3 and Comparative Examples 1 to 3 A coating composition having the composition shown in Table 1 was prepared. Table 2 shows the properties of the coating composition. Using the coating compositions obtained in Examples 1 to 3 and Comparative Examples 1 to 3, a steel sheet or a steel sheet having a floating scale adhered to the surface was applied, and the adhesion between the coating film and the steel sheet, the adhesion of the coating film Was evaluated. Table 3 shows the results.

[0092]

[Table 1]

[0093]

[Table 2]

[0094]

[Table 3]

From Table 3, it can be seen that when the coating compositions of Examples 1 to 3 were applied, even if the steel sheet had a floating scale attached to the surface, the adhesion to the coating film was good and the adhesion was good. It can be seen that it is.

[0096]

As is clear from the above description, according to the coating composition of the present invention, even if a steel material has a floating scale or the like adhered to the surface, the adhesion to the surface of the steel material is good, and the coating composition can be peeled off. And a coating film having good rust prevention can be obtained. Therefore, for example, it is suitably used as a paint for rust prevention of steel materials such as steel pipes and steel plates.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masahiro Matsumoto 19-17 Ikedanakamachi, Neyagawa-shi, Osaka Inside Nippon Paint Co., Ltd.

Claims (9)

[Claims] 1. A rust preventive coating composition comprising a compound having at least one (meth) acryloyl group in a molecule, a fatty acid-modified resin, and a photosensitizer. 2. The rust preventive according to claim 1, wherein the fatty acid-modified resin is at least one selected from a fatty acid-modified alkyd resin, a fatty acid-modified epoxy resin, and a fatty acid-modified vinyl copolymer. Paint composition. 3. The fatty acid-modified resin has an oil length of 25 to 75%.
The rust-preventive coating composition according to claim 1 or 2, wherein 4. The fatty acid residue of the fatty acid-modified resin is as follows:
The rust preventive coating composition according to any one of claims 1 to 3, which is a fatty acid residue having an unsaturated bond. 5. The rust preventive coating composition according to claim 1, wherein the composition further comprises a resin that is not modified with a fatty acid. 6. The rust-preventive coating composition according to claim 5, wherein the resin not modified with a fatty acid is an acrylic resin. 7. The composition according to claim 1, wherein the content of the fatty acid-modified resin is
The rust preventive coating composition according to any one of claims 1 to 6, wherein the content is 5 to 80% by weight in terms of solid content. 8. The rust-preventive coating composition according to claim 1, wherein the acid value of the solid content in the composition is from 20 mg to 200 mg. 9. The rust-preventive coating composition according to claim 1, which is for steel materials.