Film formation method

Abstract

To improve adhesion, lifting resistance, etc. of a coating material including an oxidative curing resin.SOLUTION: A film formation method includes: manufacturing a coating material by uniformly mixing an oxidative curing resin (A1) which is a soluble resin soluble in an aliphatic hydrocarbon-containing solvent (C) and whose weight average molecular weight is 2000-20000, an oxidative curing resin (A2) which is a soluble resin soluble in the aliphatic hydrocarbon-containing solvent (C) and whose weight average molecular weight is 28000-300000, a metal dryer (B), and the aliphatic hydrocarbon-containing solvent (C); and applying an epoxy resin undercoat material to a base material, followed by applying the coating material thereto.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a novel coating material and a film-forming method.

Background Art

[0002] Conventionally, in buildings, civil engineering structures, etc., for the purpose of imparting functionality to the base material, protecting, improving aesthetics, etc., a finish is performed by laminating various coating materials (such as primer and topcoat) to form a film. In recent years, in the field of such coating materials, there has been an increasing movement to suppress the use of aromatic hydrocarbon-containing solvents such as toluene and xylene in consideration of safety during painting, work hygiene, or the impact on air pollution. In response to such a movement, various environment-friendly coating materials using aliphatic hydrocarbon-containing solvents have been proposed.

[0003] In addition, as such an environment-friendly coating material, a coating material using an oxidation-curing resin is known (Patent Document 1, etc.). Patent Document 1 is a one-component crosslinkable (curing type) coating material that causes a crosslinking reaction by oxidation of reactive double bonds contained in unsaturated fatty acids. Such a coating material containing an oxidation-curing resin is widely adopted as a topcoat because of its excellent gloss and workability.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when such an environment-friendly coating material is used as a topcoat, lifting of the coating material may occur depending on the type of primer. Also, the gloss may be inferior in some cases.

[0006] The present invention has been made in consideration of the above-mentioned points, and has as its object to improve the lifting resistance, gloss, etc. of a coating material containing an oxidatively curable resin. [Means for solving the problem]

[0007] In order to solve these problems, the present inventors conducted extensive research and came up with the idea of a coating material containing a specific oxidatively curable resin as an essential component, thereby completing the present invention.

[0008] That is, the present invention has the following features. 1. A coating material is produced by uniformly mixing a soluble resin (A1) soluble in an aliphatic hydrocarbon-containing solvent (C) and being an oxidation-curing type resin having a weight average molecular weight of 2,000 to 20,000, a soluble resin (A2) soluble in an aliphatic hydrocarbon-containing solvent (C) and being an oxidation-curing type resin having a weight average molecular weight of 28,000 to 300,000, a metal drier (B), and an aliphatic hydrocarbon-containing solvent (C). For the base material, Epoxy resin A method for forming a coating, comprising applying an undercoat material and then applying the coating material. 2. 2. The film-forming method according to 1, wherein the mixing ratio of the oxidation-curing type resin (A1) and the oxidation-curing type resin (A2) is 99:1 to 50:50 in terms of solid content weight ratio. Effect of the Invention

[0009] According to the coating material of the present invention, it is possible to form a coating film having excellent lifting resistance, etc. Furthermore, it is possible to obtain advantageous effects in terms of finish properties such as gloss, etc. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described.

[0011] <Coating material> The coating material of the present invention contains an oxidation-curable resin (A), a metal drier (B), and an aliphatic hydrocarbon-containing solvent (C), and is a so-called weak solvent type coating material.

[0012] The oxidation-curing resin (A) of the present invention (hereinafter also referred to as the "(A) component") is oxidized and cured and dried by air oxidation by an oxidatively polymerizable double bond (oxidatively polymerizable group), and is characterized in that it is a resin soluble in an aliphatic hydrocarbon-containing non-aqueous solvent (C). Such an (A) component is not particularly limited as long as it has an oxidatively polymerizable group. For example, it can be obtained by polymerizing various vinyl monomers by a conventional method in the above-mentioned aliphatic hydrocarbon-containing non-aqueous solvent (C).

[0013] Specifically, the following resins can be used. 1) A resin obtained by copolymerizing a vinyl monomer having an oxidatively polymerizable group and another vinyl monomer copolymerizable with this monomer. 2) A resin obtained by copolymerizing an epoxy group-containing vinyl monomer and another vinyl monomer copolymerizable with this monomer, and then adding an unsaturated fatty acid to the epoxy group-containing vinyl monomer. 3) A resin obtained by copolymerizing and / or graft-polymerizing a vinyl monomer having an oxidatively polymerizable group and / or another vinyl monomer copolymerizable with this monomer with an alkyd resin. In the present invention, the resins of the above 1) to 3) can be used as a mixture.

[0014] Examples of the vinyl monomer having an oxidatively polymerizable group in the above 1) and 3) include a vinyl monomer obtained by adding an unsaturated fatty acid to an epoxy group-containing vinyl monomer. This vinyl monomer is obtained by the reaction of an epoxy group and a carboxyl group in an unsaturated fatty acid. Further, the resin of the above 2) is obtained by an addition reaction of an unsaturated fatty acid to an epoxy group in the resin. When reacting an epoxy group and an unsaturated fatty acid, a catalyst such as a tertiary amine or a quaternary ammonium salt can be used.

[0015] Specific examples of the epoxy group-containing vinyl monomer include glycidyl (meth)acrylate, β-methylglycidyl (meth)acrylate, 3,4-oxycyclohexylpropyl (meth)acrylate, allyl glycidyl ether, and the like.

[0016] Examples of the unsaturated fatty acid include linseed oil fatty acid, tung oil fatty acid, fish oil fatty acid, dehydrated castor oil fatty acid, soybean oil fatty acid, sesame oil fatty acid, poppy oil fatty acid, perilla oil fatty acid, safflower oil fatty acid, hemp seed oil fatty acid, grape seed oil fatty acid, tall oil fatty acid, sunflower oil fatty acid, cottonseed oil fatty acid, corn oil fatty acid, walnut oil fatty acid, and the like.

[0017] As the vinyl monomer having an oxidative polymerizable group in the above 1) and 3), for example, a dicyclopentadiene oxyalkyl group-containing vinyl monomer such as dicyclopentadiene oxyalkyl (meth) acrylate, and an allyl group-containing vinyl monomer such as allyl (meth) acrylate can also be used.

[0018] The content of the unsaturated fatty acid in the above 1) to 3) is preferably 1 to 20% by weight (more preferably 2 to 15% by weight) as a solid content in the component (A). By containing the unsaturated fatty acid in the component (A) within such a range, the coating material of the present invention can form a film excellent in adhesion, lift resistance, glossiness, and the like. In the present invention, “α to β” has the same meaning as “α or more and β or less”.

[0019] As the alkyd resin in the above 3), those obtained by polycondensing a polyhydric alcohol and a polyvalent carboxylic acid and modifying the same with a drying oil, an unsaturated fatty acid, or the like can be used. Examples of the polyhydric alcohol include ethylene glycol, glycerin, pentaerythritol, and the like. Examples of the polyvalent carboxylic acid include phthalic anhydride, maleic anhydride, and the like. Examples of the drying oil include linseed oil, tung oil, oiticica oil, safflower oil, and the like. The content of the alkyd resin is preferably 0 to 20% by weight (more preferably 2 to 15% by weight) as a solid content in the component (A). By containing the alkyd resin in the component (A) within such a range, the coating material of the present invention can form a film excellent in adhesion, lift resistance, glossiness, and the like.

[0020] Examples of the other vinyl monomers in the above 1) to 3) include (meth)acrylic acid alkyl esters, aromatic monomers, and other vinyl monomers.

[0021] Examples of the (meth)acrylic acid alkyl ester include methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, n-amyl (meth)acrylate, isoamyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, octadecyl (meth)acrylate, cyclohexyl (meth)acrylate, and the like. These can be used alone or in combination of two or more.

[0022] Examples of the aromatic monomer include styrene, 2-methylstyrene, vinyltoluene, t-butylstyrene, chlorostyrene, vinyl anisole, vinyl naphthalene, divinylbenzene, and the like. These can be used alone or in combination of two or more.

[0023] Examples of the other vinyl monomers include hydroxyl group-containing vinyl monomers, carboxyl group-containing vinyl monomers, amino group-containing vinyl monomers, and the like, which can also be used. Examples of the hydroxyl group-containing vinyl monomer include 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and the like. These can be used alone or in combination of two or more. Examples of the carboxyl group-containing vinyl monomer include acrylic acid, methacrylic acid, crotonic acid, maleic acid or its monoalkyl ester, itaconic acid or its monoalkyl ester, fumaric acid or its monoalkyl ester, and the like. These can be used alone or in combination of two or more. Examples of the amino group-containing vinyl monomer include N-methylaminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, dimethylaminoethyl vinyl ether, N-(2-dimethylaminoethyl)acrylamide, N-(2-dimethylaminoethyl)methacrylamide, and the like. These can be used alone or in combination of two or more.

[0024] As the component (A) of the present invention, as other vinyl monomers, those in which at least an alkyl (meth)acrylate is copolymerized, those in which an alkyl (meth)acrylate and an aromatic monomer are copolymerized, etc. are preferably included.

[0025] In the present invention, as the component (A), those having an acid value preferably of 0.1 to 20 mgKOH / g (more preferably 0.5 to 10 mgKOH / g) can be used. Such an acid value of the component (A) contributes to improving the adhesion to the undercoat material and the like. Further, if the acid value of the component (A) is within the above range, the adhesion after long-term storage is also ensured. The acid value is a value represented by the number of mg of potassium hydroxide equimolar to the acid groups contained in 1 g of the solid content of the component (A). To set the acid value of the component (A) within the above range, for example, the above carboxyl group-containing vinyl monomer may be used as the vinyl monomer during the polymerization of the component (A).

[0026] In the present invention, the component (A) is characterized by containing at least two or more having different weight average molecular weights. By containing such a component (A), excellent effects can be exhibited in terms of adhesion, lift-off resistance, etc., and in terms of finish properties such as gloss. The weight average molecular weight of the component (A) is preferably 2,000 to 300,000 (more preferably 5,000 to 250,000). The weight average molecular weight is measured by, for example, gel permeation chromatography (GPC).

[0027] In the present invention, as the component (A), it is preferable to contain an oxidation-curing resin (A1) having a weight-average molecular weight of 25,000 or less (more preferably 2,000 to 20,000) (hereinafter also referred to as the “component (A1)”). Thereby, excellent improvement effects can be obtained in terms of adhesion, anti-lifting property, finish properties such as gloss, etc. In the present invention, as the component (A), two or more kinds of the above-mentioned component (A1) can also be contained. In particular, it is preferable to contain the above-mentioned component (A1) and an oxidation-curing resin (A2) having a weight-average molecular weight exceeding 25,000 (more preferably 28,000 to 300,000) (hereinafter also referred to as the “component (A2)”). By containing such component (A1) and component (A2), more excellent improvement effects can be obtained in terms of adhesion, anti-lifting property, finish properties such as gloss, etc.

[0028] The mixing ratio of the above-mentioned component (A1) and the above-mentioned component (A2) is preferably a solid content weight ratio (A1):(A2) = 100:0 to 50:50 (more preferably 99:1 to 60:40). In such a case, the above-mentioned effects can be further enhanced.

[0029] The glass transition point of the component (A) is preferably 0°C to 80°C (more preferably 10°C to 60°C). If the glass transition point is within such a range, the film physical properties such as adhesion and durability can be enhanced. The glass transition temperature is a value obtained by the Fox calculation formula based on the vinyl monomer constituting the resin.

[0030] The metal drier (B) (hereinafter also referred to as the "(B) component") in the coating material of the present invention is a component that acts as a curing catalyst for the above-mentioned (A) component. As the (B) component, for example, known organometallic compounds such as cobalt-based, manganese-based, zirconium-based, tin-based, lead-based, zinc-based, copper-based, iron-based, calcium-based, barium-based, etc. can be used. Specifically, for example, cobalt octylate, cobalt naphthenate, manganese octylate, manganese naphthenate, zirconium octylate, zirconium naphthenate, tin octylate, lead naphthenate, zinc naphthenate, copper naphthenate, iron naphthenate, calcium octylate, calcium naphthenate, barium octylate, barium naphthenate, etc. can be mentioned. These can be used alone or in combination of two or more.

[0031] The mixing ratio of the (B) component is preferably 0.001 to 10 parts by weight (more preferably 0.01 to 5 parts by weight) in terms of metal content with respect to 100 parts by weight of the solid content of the (A) component.

[0032] The aliphatic hydrocarbon-containing solvent (C) (hereinafter also referred to as the "(C) component") of the present invention is a non-aqueous solvent that is less toxic, has high work safety, and has a smaller impact on air pollution compared to aromatic hydrocarbon-containing solvents. Examples of the (C) component include n-hexane, n-pentane, n-octane, n-nonane, n-decane, n-undecane, n-dodecane, etc. In the present invention, terpene oil, mineral spirit, etc. can also be used as the aliphatic hydrocarbon-containing solvent.

[0033] In the coating material of the present invention, in addition to the above-mentioned components, it is also possible to incorporate various components to the extent that the effects of the present invention are not affected. Examples of such components include coloring pigments, extender pigments, thickeners, film-forming aids, leveling agents, plasticizers, antifreezing agents, pH adjusters, diluents, preservatives, fungicides, algicides, antibacterial agents, dispersants, defoaming agents, ultraviolet absorbers, antioxidants, light stabilizers, fibers, catalysts, crosslinking agents, etc.

[0034] The coating material of the present invention can be produced by uniformly stirring and mixing the above components by a conventional method. The coating material of the present invention can be used in a one-component form.

[0035] <Coating formation method> The coating material of the present invention can be mainly applied for protecting the body and improving the aesthetic appearance of buildings, civil engineering structures, etc. For example, it is suitable as an overcoating material for coating on a base material via an undercoating film. In the present invention, for example, a film can be formed by applying an undercoating material to a base material and then applying the coating material of the present invention.

[0036] The base material is mainly used for protecting the body of buildings, civil engineering structures, etc. For example, it can be used for surface finishing of various base materials such as concrete, mortar, ceramic tiles, siding boards, extruded plates, color steel plates, copper plates, aluminum plates, titanium plates, stainless steel plates, galvanized steel plates, metals, glass, plastics, wood, plywood, etc. These base materials may have an old coating film on their surfaces. In the coating formation method of the present invention, the undercoating material can be directly applied to the base material, but it is also possible to perform some surface treatment (such as undercoating treatment with an undercoating material such as a sealer, primer, surfacer, filler, putty, etc.) on the base material in advance.

[0037] As the undercoating material, various known or commercially available undercoating materials can be used. Specifically, examples of the undercoating material include an acrylic resin undercoating material, an epoxy resin undercoating material, a urethane resin undercoating material, a chlorinated rubber-based undercoating material, etc. Such undercoating materials can be either a clear type or a colored type. Also, those containing rust-preventive pigments such as phosphate-based, molybdate-based, zinc-based, etc. may be used.

[0038] Among these, when an epoxy resin undercoat material is used in the present invention, remarkable effects can be obtained. For example, when a coating material containing an oxidation-curing resin and a metal drier is overcoated on the epoxy resin undercoat material, phenomena such as dissolution of the coating material film and lifting may occur. On the contrary, by using the coating material of the present invention, the occurrence of such problems can be suppressed, and it has excellent adhesion, lift resistance, and can improve the finishability and the like.

[0039] As the epoxy resin undercoat material, those containing one or more epoxy resins as a binder component can be used. Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, alkyl ether type epoxy resin, hydrogenated bisphenol A type epoxy resin, or modified products thereof. The form of the epoxy resin undercoat material may be either a one-component type or a two-component type. In the case of the two-component type, those containing an amine compound or the like as a curing agent can be used.

[0040] The undercoat material has the above binder component as an essential component, and it is also possible to blend various components to the extent that it does not affect the effects of the present invention. Examples of such components include coloring pigments, extender pigments, rust preventives, thickeners, film-forming aids, leveling agents, plasticizers, antifreezing agents, pH adjusters, diluents, antiseptics, antifungal agents, algicides, antibacterial agents, dispersants, defoamers, ultraviolet absorbers, antioxidants, light stabilizers, fibers, catalysts, crosslinking agents, and the like.

[0041] Such an undercoat material can be applied by using various methods such as brush coating, roller coating, spray coating, roll coater, flow coater, etc. Regarding the coating amount, although it depends on the form of the undercoat material, it is preferably 0.05 to 3 kg / m 2 (more preferably 0.05 to 2 kg / m 2 ).

[0042] As a method for applying the coating material of the present invention, for example, various methods such as brush coating, roller coating, spray coating, roll coater, flow coater, etc. can be used. At this time, the coating material of the present invention can also be appropriately diluted with an aliphatic hydrocarbon-based solvent. Also, the coating amount is preferably 0.1 to 0.5 kg / m 2 or so. Furthermore, the coating material may be finished with one layer, or two or more layers may be laminated and finished.

Examples

[0043] Examples are shown below to make the features of the present invention clearer.

[0044] (Coating materials 1 to 10) Using the raw materials shown below and mixing them in the formulations shown in Table 1 by a conventional method, coating materials 1 to 10 were produced.

[0045] In each topcoat material, the following raw materials were used. (A) Oxidation-curing resin (A-1) Dehydrated castor oil fatty acid-modified product of styrene·isobutyl methacrylate·2-ethylhexyl acrylate·glycidyl methacrylate copolymer [weight average molecular weight: 12,000, solid content: 50% by weight (content of unsaturated fatty acid in solid content: 10% by weight), acid value: 1.5 mgKOH / g, solvent: mineral spirit solution] (A-2) Soybean oil fatty acid-modified product of styrene·isobutyl methacrylate·2-ethylhexyl acrylate·glycidyl methacrylate copolymer [weight average molecular weight: 25,000, solid content: 50% by weight (content of unsaturated fatty acid in solid content: 10% by weight), acid value: 1.5 mgKOH / g, solvent: mineral spirit solution] (A-3) Soybean oil fatty acid-modified product of styrene·isobutyl methacrylate·2-ethylhexyl acrylate·glycidyl methacrylate copolymer [weight average molecular weight: 40,000, solid content: 50% by weight (content of unsaturated fatty acid in solid content: 10% by weight), acid value: 1.5 mgKOH / g, solvent: mineral spirit solution] (A-4) Copolymer of glycidyl methacrylate and soybean oil fatty acid, styrene, isobutyl methacrylate, 2-ethylhexyl acrylate, dimethylaminoethyl methacrylate, and alkyd resin [weight average molecular weight: 45,000, solid content: 50% by weight (content of unsaturated fatty acid in solid content: 8% by weight, content of alkyd resin: 10% by weight), acid value: 1.5 mgKOH / g, solvent: mineral spirit solution] (B) Metal drier · Mixture of cobalt naphthenate and zirconium naphthenate (mineral spirit solution, Co content 0.3% by weight, Zr content 3% by weight) (C) Aliphatic hydrocarbon-containing non-aqueous solvent · Mixture of mineral spirit and petroleum mixed solvent containing aromatic hydrocarbon (ratio of aliphatic hydrocarbon content: 65% by weight) (D) Others · Coloring pigment: titanium oxide · Additives: defoaming agent, dispersant, ultraviolet absorber, light stabilizer, etc.

[0046] (Examples 1 - 8, Comparative Examples 1 - 2) <Preparation of Specimen [I]>[[]]END]] For a 200×150 mm iron plate, a two-component reaction-curing epoxy resin undercoat [main component: phenol novolac epoxy resin with an epoxy equivalent of 1350 g / eq, curing agent component: polyamide amine with an active hydrogen equivalent of 360 g / eq] was applied at a coating amount of 0.1 kg / m 2 by brush coating and dried and cured for 24 hours under standard conditions. Next, the coating material obtained by the above method was applied at a coating amount of 0.12 kg / m 2 using a roller, dried and cured for 16 hours under standard conditions to form a film, and a cross cut was made with a cutter. Then, the same coating material was applied at a coating amount of 0.12 kg / m 2 using a roller and cured for 24 hours under standard conditions to obtain Specimen [I].[[]]END]]

[0047] <Lifting resistance evaluation>[[]]END]] For Specimen [I], the surface condition was observed and evaluated in the following 5 grades. The results are shown in Table 1. AA: No abnormality was observed. A: Almost no abnormality was observed (there was a slight shrinkage). B: A slight lifting phenomenon (there was a slight shrinkage) was observed at the cut part. C: A lifting phenomenon (shrinkage over the entire surface) was observed. D: A dissolution phenomenon was observed.

[0048] <Preparation of Specimen [II]> For a 200×150 mm iron plate, a two-component reaction-curing epoxy resin undercoat material (the same as above) was applied by brush at an application rate of 0.1 kg / m 2 and dried and cured for 24 hours under standard conditions. Next, the coating material obtained by the above method was applied using a roller at an application rate of 0.12 kg / m 2 After drying and curing for 16 hours under standard conditions, the same coating material was applied using a roller at an application rate of 0.12 kg / m 2 The specimen coated at this rate and cured for 24 hours under standard conditions was designated as Specimen [II], and the following evaluations were carried out.

[0049] <Finish quality> For Specimen [II], its finished appearance (such as gloss) was visually confirmed. The results are shown in Table 1. The evaluation criteria were based on four levels (excellent: A > B > C > D: poor), where those with excellent finish quality were rated as "A" and those with poor finish quality were rated as "D".

[0050]

Table 1

Claims

1. An oxidation-curing type resin (A1) which is a soluble resin soluble in an aliphatic hydrocarbon-containing solvent (C) and has a weight average molecular weight of 2,000 to 20,000, an oxidation-curing type resin (A2) which is a soluble resin soluble in an aliphatic hydrocarbon-containing solvent (C) and has a weight average molecular weight of 28,000 to 300,000, a metal drier (B), and an aliphatic hydrocarbon-containing solvent (C) are uniformly mixed to produce a coating material. A film forming method characterized by applying an epoxy resin undercoat material to a substrate and then applying the above coating material.

2. The film forming method according to Claim 1, wherein the mixing ratio of the oxidation-curing type resin (A1) and the oxidation-curing type resin (A2) is a solid content weight ratio of 99:1 to 50:50.

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