Film formation method

Abstract

To provide a film formation method for coating an undercoating material to a base material, and then coating a final coating material containing a specific oxidation curable resin as an essential component thereto.SOLUTION: A film formation method for coating an undercoating material to a base material, and then coating a final coating material thereto, in which the final coating material contains an oxidation curable resin (A), a metal drier (B) and an aliphatic hydrocarbon-containing solvent, and the oxidation curable resin (A) has an amine value of 0.1 mgKOH / g or more and contains 5 wt.% or more and 50 wt.% or less of an alkyd resin.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a novel method for forming a coating. [Background technology]

[0002] Conventionally, in the case of buildings, civil engineering structures, etc., finishing is carried out by laminating various coating materials (undercoat materials, topcoat materials, etc.) to form a coating film for the purpose of imparting functionality to the substrate and improving protection and aesthetics. In recent years, in the field of such coating materials, there has been a growing movement to reduce the use of aromatic hydrocarbon-containing solvents such as toluene and xylene, taking into consideration safety during painting, work hygiene, and the impact on air pollution. In response to this movement, various environmentally friendly coating materials using aliphatic hydrocarbon-containing solvents have been proposed.

[0003] In addition, as such an environmentally friendly coating material, a coating material using an oxidation-curing resin is known (Patent Document 1, etc.). Patent Document 1 is a one-liquid crosslinking (curing) coating material that causes a crosslinking reaction by oxidation between reactive double bonds contained in unsaturated fatty acids. Such coating materials containing oxidation-curing resins are often used as topcoats because they have excellent gloss and workability. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2001-262055 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, when such environmentally friendly coating materials are used as topcoats, depending on the type of undercoat, the adhesion of the topcoat may be insufficient, causing lifting, etc. Also, gloss may be poor.

[0006] The present invention has been made in consideration of these points, and aims to improve adhesion, lifting resistance, etc., in a coating formation method in which a base coat material is applied to a substrate and then a top coat material containing an oxidatively cured resin is applied. [Means for solving the problem]

[0007] In order to solve such problems, the inventors have conducted extensive research and have come up with a method of forming a coating in which a base coat is applied to a substrate, and then a top coat containing a specific oxidative curing resin as an essential component is applied, thereby completing the present invention.

[0008] That is, the present invention has the following features. 1. A coating method in which a base material is applied to a substrate and then a topcoat material is applied to the substrate. The topcoat material comprises an oxidatively curable resin (A), a metal drier (B), and an aliphatic hydrocarbon-containing solvent; The oxidative curing resin (A) is a mineral spirit solution of an oxidative curing resin, The oxidation-curable resin (A) is Oxidatively curable resin (A) solid content The amine value is 0.1 mgKOH / g or more, and the alkyd resin The content of the solid content of the oxidative curing resin (A) is 10% by weight or more and 22% by weight or less and , The aliphatic hydrocarbon-containing solvent is selected from the group consisting of n-hexane, n-pentane, n-octane, n-nonane, n-decane, n-undecane, n-dodecane, terpine oil, and mineral spirits, and is characterized in that the coating forming method contains mineral spirits. 2. The oxidatively curable resin (A) is an alkyd resin modified acrylic resin. Mineral spirits solution 1. The method for forming a coating film according to claim 1, 3. The method for forming a coating according to 1 or 2, wherein the undercoat material contains an epoxy resin. Effect of the Invention

[0009] According to the coating film forming method of the present invention, it is possible to form a coating film that is excellent in adhesion to the undercoat material, 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] The present invention relates to a coating method for applying a base coat material to a substrate and then applying a top coat material, and can be applied mainly to protect the framework and improve the aesthetics of buildings, civil engineering structures, etc. In particular, the present invention is characterized by applying a top coat material containing a specific oxidative curing resin as an essential component.

[0012] <Base material> The present invention is intended to be used mainly for protection of the framework of buildings, civil engineering structures, etc., and can be used for surface finishing of various substrates such as concrete, mortar, porcelain tiles, siding boards, extrusion molding panels, color steel panels, copper panels, aluminum panels, titanium panels, stainless steel panels, galvanized steel panels, metals, glass, plastics, wood, plywood, etc. These substrates may have an old coating film on their surfaces. In the coating formation method of the present invention, the undercoat material can be applied directly to the substrate, but it is also possible to subject the substrate to some kind of surface treatment in advance (such as surface treatment using an undercoat material such as a sealer, primer, surfacer, filler, or putty).

[0013] <Undercoating material> As the undercoat material of the present invention, various known or commercially available undercoat materials can be used.Specific undercoat materials include, for example, acrylic resin undercoat materials, epoxy resin undercoat materials, urethane resin undercoat materials, chlorinated rubber undercoat materials, etc.Such undercoat materials may be either clear type or colored type.In addition, they may contain rust-preventive pigments such as phosphate-based, molybdate-based, and zinc-based.

[0014] Among these, the present invention can obtain a remarkable effect when an epoxy resin undercoat material is used. Usually, when a topcoat material containing an oxidative curing resin and a metal dryer is applied on an epoxy resin undercoat material, the reactivity of the topcoat material may decrease due to the interaction between the undercoat material and the metal dryer. Therefore, when the topcoat material is applied twice or more, the phenomenon of the lower topcoat material coating film dissolving or lifting (lifting) is likely to occur. In contrast, the present invention uses a specific topcoat material to suppress the occurrence of such defects, and can improve adhesion, lifting resistance, and finish.

[0015] The epoxy resin undercoat material may contain one or more epoxy resins as a binder component. 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, and modified products thereof. The epoxy resin undercoat material may be in the form of either a one-component type or a two-component type. In the case of the two-component type, a hardener containing an amine compound or the like can be used.

[0016] The undercoat material is essential for the binder component, and can also be mixed with various components to the extent that it does not affect the effect of the present invention. Such components include, for example, color pigments, extender pigments, rust inhibitors, thickeners, film-forming assistants, leveling agents, plasticizers, antifreeze agents, pH adjusters, diluents, preservatives, antifungal agents, algae inhibitors, antibacterial agents, dispersants, defoamers, ultraviolet absorbers, antioxidants, light stabilizers, fibers, catalysts, crosslinking agents, etc.

[0017] Such undercoat materials can be applied by various methods, such as brush coating, roller coating, spray coating, roll coater, flow coater, etc. The amount of application depends on the form of the undercoat material, but is preferably 0.05 to 3 kg / m 2 (More preferably 0.05 to 2 kg / m 2 ).

[0018] <Top coat material> The topcoat material of the present invention contains an oxidatively curable resin (A), a metal drier (B), and an aliphatic hydrocarbon-containing solvent, and is a so-called weak solvent type coating material.

[0019] The oxidatively curable resin (A) of the present invention (hereinafter also referred to as "component (A)") is cured and dried by air oxidation due to the oxidatively polymerizable double bond (oxidatively polymerizable group). Such component (A) is not particularly limited as long as it has an oxidatively polymerizable group, and the type of resin is not particularly limited, and examples thereof include acrylic resin, polyester resin, polyurethane resin, and epoxy resin.

[0020] In the present invention, it is preferable to contain an oxidatively curable acrylic resin as component (A). In the present invention, it is preferable to contain an alkyd resin-modified acrylic resin as the oxidatively curable acrylic resin, and specifically, the following resins can be used. 1) A resin obtained by polymerizing an alkyd resin with a vinyl monomer capable of copolymerizing and / or graft polymerizing with the alkyd resin. 2) A resin obtained by reacting an alkyd resin with an acrylic resin having a group reactive with the alkyd resin (such as a carboxyl group, a hydroxyl group, or an epoxy group).

[0021] As the alkyd resin in the above 1) and 2), a resin obtained by a condensation reaction of a polyhydric alcohol, a polybasic acid, and an unsaturated fatty acid and / or a fat or oil can be used.

[0022] Examples of polyhydric alcohols include dihydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, and hexanediol, trihydric alcohols such as glycerin and trimethylolpropane, tetrahydric alcohols such as pentaerythritol, and hexahydric alcohols such as dipentaerythritol, mannitol, and D-sorbitol. These can be used alone or in combination of two or more.

[0023] Examples of polybasic acids include phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, succinic acid, succinic anhydride, maleic acid, maleic anhydride, adipic acid, sebacic acid, tetrahydrophthalic anhydride, etc. These can be used alone or in combination of two or more.

[0024] The unsaturated fatty acid is not particularly limited as long as it has at least one oxidative polymerizable group (unsaturated carbon bond) in the molecule, and includes known unsaturated fatty acids. Examples of unsaturated fatty acids include drying oil fatty acids and semi-drying oil fatty acids. In the present invention, the drying oil fatty acid refers to a fatty acid with a solid iodine value of 130 or more, and the semi-drying oil fatty acid refers to a fatty acid with a solid iodine value of 100 or more and less than 130.

[0025] Examples of drying oil fatty acids and semi-drying oil fatty acids include fish oil fatty acids, dehydrated castor oil fatty acids, safflower oil fatty acids, linseed oil (linseed oil) fatty acids, tung oil fatty acids, soybean oil fatty acids, sesame oil fatty acids, poppy oil fatty acids, perilla oil fatty acids, hemp seed oil fatty acids, grape kernel oil fatty acids, corn oil fatty acids, tall oil fatty acids, sunflower oil fatty acids, cottonseed oil fatty acids, walnut oil fatty acids, rubber seed oil fatty acids, hydinoic acid fatty acids, oleic acid, linoleic acid, linolenic acid, etc. These can be used alone or in combination of two or more.

[0026] If necessary, drying oil fatty acid and / or semi-drying oil fatty acid can be used in combination with non-drying oil fatty acid. In the present invention, non-drying oil fatty acid refers to a fatty acid having a solid iodine value of less than 100. Examples of non-drying oil fatty acid include coconut oil fatty acid, hydrogenated coconut oil fatty acid, palm oil fatty acid, caproic acid, capric acid, lauric acid, myristic acid, palmitic acid, and stearic acid. These can be used alone or in combination of two or more.

[0027] The fats and oils include fats and oils having unsaturated carbon bonds, such as drying oils or semi-drying oils, such as fish oil, dehydrated castor oil, castor oil, safflower oil, linseed oil, tung oil, soybean oil, sesame oil, poppy seed oil, perilla oil, hemp seed oil, grape kernel oil, corn oil, tall oil, sunflower oil, cottonseed oil, walnut oil, rubber seed oil, etc. These can be used alone or in combination of two or more kinds.

[0028] As the alkyd resin in the above 1) and 2), there can be used an alkyd resin having an oxidative polymerizable group in which an unsaturated carbon bond derived from an unsaturated fatty acid and / or fat is introduced.

[0029] The component (A) of the present invention is characterized in that the content of the alkyd resin is 5% by weight or more and 50% by weight or less (preferably 10% by weight or more and 40% by weight or less) as solid content in the solid content of the component (A). In such a case, excellent adhesion and lifting resistance can be exhibited.

[0030] The vinyl monomer in 1) above, or the vinyl monomer constituting the acrylic resin in 2) above, is, for example, one that contains an alkyl (meth)acrylate ester as an essential component, and preferably contains an aromatic monomer and other vinyl monomers, etc.

[0031] Examples of (meth)acrylic acid alkyl esters 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, etc. These can be used alone or in combination of two or more.

[0032] Examples of aromatic monomers include styrene, 2-methylstyrene, vinyltoluene, t-butylstyrene, chlorostyrene, vinylanisole, vinylnaphthalene, divinylbenzene, etc. These can be used alone or in combination of two or more.

[0033] The (A) component of the present invention is characterized by having an amine value of 0.1 mgKOH / g or more (preferably 0.3 to 10 mgKOH / g, more preferably 0.5 to 8 mgKOH / g). Such an amine value of the (A) component can exert a remarkable effect in improving adhesion to various undercoating materials and lifting resistance, especially when the undercoating material contains an epoxy resin as a resin component. The amine value is a value represented by mg of potassium hydroxide equivalent to the moles of acid groups contained in 1 g of solid content of the (A) component.

[0034] In order to set the amine value of the (A) component within the above range, for example, it is preferable to use an amino group-containing vinyl monomer as the vinyl monomer during polymerization of the (A) component. This can improve adhesion and lifting resistance. Examples of amino group-containing vinyl monomers include N-methylaminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, dimethylaminoethyl vinyl ether, N-(2-dimethylaminoethyl)acrylamide, and N-(2-dimethylaminoethyl)methacrylamide. These can be used alone or in combination of two or more.

[0035] In the present invention, other vinyl monomers such as hydroxyl group-containing vinyl monomers, carboxyl group-containing vinyl monomers, and epoxy group-containing vinyl monomers can also be used. Examples of hydroxyl group-containing vinyl monomers include 2-hydroxyethyl (meth)acrylate and hydroxypropyl (meth)acrylate; 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, etc.; Examples of epoxy group-containing vinyl monomers include glycidyl (meth)acrylate, diglycidyl (meth)acrylate, allyl glycidyl ether, diglycidyl fumarate, 3,4-epoxycyclohexyl (meth)acrylate, 3,4-epoxyvinylcyclohexane, ε-caprolactone-modified glycidyl (meth)acrylate, β-methylglycidyl (meth)acrylate, and the like; These can be used alone or in combination of two or more.

[0036] In addition to the alkyd resin, the component (A) of the present invention can also have an oxidatively polymerizable group introduced therein. In this case, for example, when polymerizing the component (A), it is possible to use a vinyl monomer having an oxidatively polymerizable group, or a vinyl monomer in which an unsaturated fatty acid is added to an epoxy group-containing vinyl monomer. It is also possible to add an unsaturated fatty acid to an epoxy group-containing resin obtained by copolymerizing an epoxy group-containing vinyl monomer with another vinyl monomer copolymerizable with this monomer.

[0037] Examples of vinyl monomers having an oxidative polymerizable group include vinyl monomers containing a dicyclopentadieneoxyalkyl group, such as dicyclopentadieneoxyalkyl (meth)acrylate, and vinyl monomers containing an allyl group, such as allyl (meth)acrylate. These may be used alone or in combination of two or more.

[0038] The vinyl monomer in which an unsaturated fatty acid is added to an epoxy group-containing vinyl monomer is obtained by the reaction of an epoxy group with a carboxyl group in the unsaturated fatty acid. The epoxy group-containing vinyl monomer may be the same as above. The unsaturated fatty acid may be the same as above.

[0039] The component (A) of the present invention may have an acid value. The acid value is preferably 0.1 to 30 mgKOH / g (more preferably 0.5 to 10 mgKOH / g, more preferably 1 to 8 mgKOH / g). Such an acid value of the component (A) can improve the curability and enhance the recoatability. The acid value is a value represented by the number of mg of potassium hydroxide equivalent to the moles of acid groups contained in 1 g of resin solids. In order to set the acid value in the component (A) within the above range, for example, an alkyd resin having an acid value may be used as the alkyd resin, or the above carboxyl group-containing vinyl monomer may be used as the vinyl monomer.

[0040] The metal drier (B) in the coating material of the present invention is a component that acts as a curing catalyst for the above-mentioned component (A). As the component (B), 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, and barium-based compounds can be used. Specific examples include 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, and barium naphthenate. These can be used alone or in combination of two or more.

[0041] The mixing ratio of the component (B) is preferably 0.001 to 10 parts by weight (more preferably 0.01 to 5 parts by weight) in terms of metal content per 100 parts by weight of the solid content of the component (A).

[0042] The aliphatic hydrocarbon-containing solvent of the present invention is a non-aqueous solvent that is less toxic, safer to work with, and less susceptible to air pollution than aromatic hydrocarbon-containing solvents. Examples of aliphatic hydrocarbons include n-hexane, n-pentane, n-octane, n-nonane, n-decane, n-undecane, and n-dodecane. In the present invention, terpine oil, mineral spirits, and the like can also be used as the aliphatic hydrocarbon-containing solvent.

[0043] In the topcoat material of the present invention, in addition to the above-mentioned components, various components can be blended to the extent that they do not affect the effect of the present invention. Such components include, for example, coloring pigments, body pigments, thickeners, film-forming assistants, leveling agents, plasticizers, antifreeze agents, pH adjusters, diluents, preservatives, antifungal agents, algae inhibitors, antibacterial agents, dispersants, defoamers, ultraviolet absorbers, antioxidants, light stabilizers, fibers, catalysts, crosslinking agents, etc.

[0044] The topcoat material of the present invention can be manufactured by uniformly stirring and mixing the above-mentioned components by a conventional method. The topcoat material of the present invention can be used in the form of a one-liquid type.

[0045] The topcoat material of the present invention can be applied to the above-mentioned substrate via the above-mentioned undercoat material coating film. In this case, the composition of the present invention can also be appropriately diluted with an aliphatic hydrocarbon solvent. As a coating method, various methods can be used, such as brush coating, roller coating, spray coating, roll coater, flow coater, etc. The coating amount is preferably 0.1 to 0.5 kg / m 2 The topcoat material can be finished in one layer, or two or more layers can be laminated to finish it. EXAMPLES

[0046] The following examples will clarify the features of the present invention.

[0047] (Top coat material 1~5) The raw materials shown below were mixed in the usual manner according to the composition shown in Table 1 to produce topcoat materials 1 to 5.

[0048] The following materials were used for each topcoat: ·Oxidation hardening resin 1 Alkyd resin modified acrylic resin [copolymer of alkyd resin, styrene, isobutyl methacrylate, 2-ethylhexyl acrylate, and dimethylaminoethyl methacrylate in mineral spirits, amine value: 0.4 mg KOH / g, acid value: 3 mg KOH / g, solids: 50% by weight (alkyd resin content in solids: 22% by weight)] ·Oxidation hardening resin 2 Alkyd resin modified acrylic resin [copolymer of alkyd resin, styrene, isobutyl methacrylate, 2-ethylhexyl acrylate, and dimethylaminoethyl methacrylate in mineral spirits, amine value: 2 mg KOH / g, acid value: 3 mg KOH / g, solids: 50% by weight (alkyd resin content in solids: 18% by weight)] ·Oxidation hardening resin 3 Alkyd resin modified acrylic resin [copolymer of alkyd resin, styrene, isobutyl methacrylate, 2-ethylhexyl acrylate, and dimethylaminoethyl methacrylate in mineral spirits, amine value: 0.4 mg KOH / g, acid value: 3 mg KOH / g, solids: 50% by weight (alkyd resin content in solids: 8% by weight)] ·Oxidation hardening resin 4 Alkyd resin modified acrylic resin [copolymer of alkyd resin, styrene, isobutyl methacrylate and 2-ethylhexyl acrylate in mineral spirits, amine value: 0 mg KOH / g, acid value: 3 mg KOH / g, solid content: 50% by weight (alkyd resin content in solid content: 3% by weight)] ·Oxidation hardening resin 5 Alkyd resin modified acrylic resin [copolymer of alkyd resin, styrene, isobutyl methacrylate and 2-ethylhexyl acrylate in mineral spirits, amine value: 0 mg KOH / g, acid value: 3 mg KOH / g, solid content: 50% by weight (alkyd resin content in solid content: 8% by weight)] Metal dryer: Mixture of cobalt naphthenate and zirconium naphthenate (mineral spirit solution, Co content 0.3 wt%, Zr content 3 wt%) Color pigment: Titanium dioxide Additives: Antifoaming agents, dispersants, light stabilizers, etc. Solvent: Non-aqueous solvent containing aliphatic hydrocarbons (mixture of mineral spirits and petroleum solvent containing aromatic hydrocarbons, aliphatic hydrocarbon content: 65% by weight)

[0049] (Examples 1 to 3, Comparative Examples 1 to 2) A two-component reactive curing epoxy resin undercoat [main component: phenol novolac epoxy resin with an epoxy equivalent of 1350g / eq, hardener component: polyamide amine with an active hydrogen equivalent of 360g / eq] was applied at a rate of 0.1kg / m to a 200 x 150mm tinplate. 2 The paint was then brushed on and left to dry for 24 hours under standard conditions. Next, the topcoat material obtained by the above method was applied at a coating amount of 0.12 kg / m 2 After drying and curing for the specified time (24 hours, 48 ​​hours), the same topcoat material was applied at a coating amount of 0.12 kg / m. 2 The test specimens were then brushed with the paint and evaluated as follows. The results are shown in Table 1.

[0050] (Lifting resistance evaluation) The surface condition of the test specimens prepared by the above method was observed and evaluated according to the following four-level scale. - Those where no abnormality was found are rated "A". - Items with almost no abnormalities (some shrinkage) are rated as "B" - If lifting is observed (shrinkage on the entire surface), it is rated as "C". - "D" indicates that dissolution was observed

[0051] (Adhesion) The coating of the test specimen prepared by the above method was cross-cut with a cutter knife, and tape was applied to the cross-cut area and then peeled off to evaluate adhesion. The evaluation was done on a four-level scale (A>B>C>D: poor), with "A" being the one where no abnormality was observed and "D" being the one where peeling was observed.

[0052] (Finishability) The finished appearance (color tone, gloss, etc.) of the test specimens prepared by the above method was visually inspected. Evaluation was performed on a four-level scale (A>B>C>D: poor), with "A" representing excellent finish and "D" representing poor finish.

[0053] [Table 1]

Claims

1. A coating method for applying a base coat material to a substrate and then applying a top coat material to the substrate, The topcoat material comprises an oxidatively curable resin (A), a metal dryer (B), and an aliphatic hydrocarbon-containing solvent; The oxidation-curing resin (A) is a mineral spirit solution of an oxidation-curing resin, The oxidatively curable resin (A) has an amine value of 0.1 mgKOH / g or more relative to the solid content of the oxidatively curable resin (A), and the content of the alkyd resin in the solid content of the oxidatively curable resin (A) is 10% by weight or more and 22% by weight or less in terms of solid content, The aliphatic hydrocarbon-containing solvent is selected from the group consisting of n-hexane, n-pentane, n-octane, n-nonane, n-decane, n-undecane, n-dodecane, terpine oil, and mineral spirits, and is characterized in that the coating forming method contains mineral spirits.

2. 2. The method for forming a coating film according to claim 1, wherein the oxidatively curable resin (A) is a solution of an alkyd resin-modified acrylic resin in mineral spirits.

3. 3. The method for forming a coating film according to claim 1, wherein the undercoat material contains an epoxy resin.

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