JP7506509B2 - Covering material - Google Patents

Description

The present invention relates to a novel coating material.

When painting buildings, civil engineering structures, etc., a primer is applied as a covering material to ensure adhesion to the base material that constitutes them, and then a topcoat is applied.

Recently, there have been many cases of painting existing coating surfaces (old coating surfaces) that have deteriorated over time. In such cases, a primer is selected and applied to ensure adhesion according to the deterioration state of the existing coating surface, and then a topcoat is applied.

The primer used here plays a major role in improving the adhesion of the topcoat to the substrate and existing coating surface (hereinafter collectively referred to as the "base").

Traditionally, an appropriate undercoat material has been selected according to the type and condition of the base. For example, the epoxy-based undercoat material described in Patent Documents 1 and 2 is one of the undercoat materials that has been widely used.

JP 2000-319582 A Japanese Patent Application Laid-Open No. 11-199648

However, in recent years, the variety of base materials has increased in line with the diversification of buildings and civil engineering structures, and it has become necessary to deal with a variety of base materials, from hard to elastic, for example, making the selection of primers more complicated. Furthermore, coating surfaces with high functionality, such as high durability and stain resistance, have appeared, and existing primers are no longer able to handle these coating surfaces.

As a result of extensive research into these problems, the inventors came up with the idea of a coating material that contains, in addition to an epoxy resin and an amine curing agent, a pigment and a non-aqueous solvent under specific conditions, and that also has specific bending resistance, and thus completed the present invention.

That is, the present invention has the following features.
1. A coating material containing an epoxy resin, an amine curing agent, a pigment, and a non-aqueous solvent,
The epoxy resin contains a dimer acid-modified epoxy resin in an amount of 70 to 100% by weight in terms of solid content,
The amine curing agent has an active hydrogen equivalent (based on solid content) of 40 to 120 g/eq.
a compounding ratio of the epoxy resin to the amine curing agent, expressed as [(amount of the amine curing agent/active hydrogen equivalent of the amine curing agent)/(amount of the epoxy resin/epoxy equivalent of the epoxy resin)], is 0.3 to 1.0;
The non-aqueous solvent includes a non-aqueous solvent having an aniline point of 12 to 70° C., and the non-aqueous solvent is at least one selected from mineral spirits, petroleum ether, petroleum naphtha, solvent naphtha, and kerosene;
The pigment volume concentration is 1 to 19%,
A coating material characterized by exhibiting bending resistance in a bending resistance test using a cylindrical mandrel having a mandrel diameter of 5 mm or less.
2. The coating material according to 1., characterized in that the non-volatile content is 30 to 90% by weight.

The coating material of the present invention exhibits excellent adhesion and other suitability for a wide variety of substrates.

The coating material of the present invention contains an epoxy resin, an amine curing agent, a pigment, and a non-aqueous solvent.

The epoxy resin and amine curing agent undergo a curing reaction during coating formation and act as resin components. Among these, examples of epoxy resins include flexible epoxy resins and rigid epoxy resins, and in the present invention, an embodiment that includes at least flexible epoxy resin is preferable.

Examples of flexible epoxy resins include aliphatic modified epoxy resins, butadiene-based epoxy resins, ε-caprolactone modified epoxy resins, thiol-based epoxy resins, amine modified epoxy resins, rubber modified epoxy resins, urethane modified epoxy resins, polyol modified epoxy resins, and fatty acid modified epoxy resins. These can be used alone or in combination of two or more. Of these, fatty acid modified epoxy resins are preferred.

The ratio of flexible epoxy resin in the epoxy resin of the coating material of the present invention (converted into solid content) is preferably 50% by weight or more, more preferably 70 to 100% by weight, from the viewpoints of conformability to the substrate, adhesion, etc.

Fatty acid modified epoxy resins are obtained by subjecting an aliphatic polybasic acid compound to an addition reaction with an epoxy resin. For example, an esterification reaction can be used for the addition reaction. Examples of the epoxy resins used here include bisphenol A type epoxy resins, bisphenol F type epoxy resins, and various other epoxy resins such as those exemplified by the hard epoxy resins described below. Examples of the aliphatic polybasic acid compounds include maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, citraconic acid, tetrahydrophthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic acid, hexahydrophthalic anhydride, cyclohexanedicarboxylic acid, succinic acid, malonic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, 1,12-docane diacid, and dimer acid. Among these, dimer acid is preferred.

Dimer acids are dimers of unsaturated fatty acids. Examples of unsaturated fatty acids that make up dimer acids include oleic acid, elaidic acid, cetoleic acid, sorbic acid, linoleic acid, linoleic acid, arachidonic acid, soybean oil fatty acids, tall oil fatty acids, and linseed oil fatty acids.

Dimer acid-modified epoxy resin obtained by addition reaction of dimer acid with epoxy resin is suitable as the epoxy resin of the coating material of the present invention. The ratio of dimer acid-modified epoxy resin in the epoxy resin of the coating material of the present invention (converted into solid content) is preferably 50% by weight or more, more preferably 70 to 100% by weight, from the viewpoints of conformability to the substrate, adhesion, etc.

Examples of hard epoxy resins include bisphenol type epoxy resins such as bisphenol A type epoxy resins and bisphenol F type epoxy resins, phenol novolac type epoxy resins such as phenol novolac type bisphenol A epoxy resins and phenol novolac type bisphenol F epoxy resins, novolac type epoxy resins such as cresol novolac type epoxy resins and bisphenol A novolac type epoxy resins, alicyclic epoxy resins, hydrogenated bisphenol A type epoxy resins, glycidyl ether type epoxy resins, bisphenol S type epoxy resins, biphenyl type epoxy resins, dicyclo type epoxy resins, naphthalene type epoxy resins, etc. These can be used alone or in combination of two or more.

The epoxy resin used in the present invention has an epoxy equivalent (per solid content) of preferably 300 to 3000 g/eq, more preferably 400 to 2000 g/eq, even more preferably 450 to 1500 g/eq, and particularly preferably 500 to 1100 g/eq. When the epoxy equivalent is equal to or greater than the lower limit, it is suitable in terms of conformability to the substrate, adhesion, etc. When the epoxy equivalent is equal to or less than the upper limit, it is suitable in terms of blister resistance, adhesion, suitability as a topcoat material, etc. The epoxy equivalent is the value obtained by dividing the molecular weight of the epoxy resin by the number of epoxy groups. In the present invention, "α to β" is synonymous with "α or more and β or less."

Examples of amine hardeners include polyamine compounds such as aliphatic polyamines, alicyclic polyamines, aromatic polyamines, heterocyclic polyamines, aliphatic polyamides, alicyclic polyamides, aromatic polyamides, aliphatic polyamidoamines, alicyclic polyamidoamines, and aromatic polyamidoamines. These can be used alone or in combination of two or more. In the present invention, among these, one or more aliphatic amine hardeners selected from aliphatic polyamines, aliphatic polyamides, and aliphatic polyamidoamines can be preferably used.

The amine curing agent used in the present invention preferably has an active hydrogen equivalent (per solid content) of 40 to 200 g/eq, more preferably 50 to 120 g/eq, and even more preferably 60 to 95 g/eq. By having the active hydrogen equivalent within the above range, sufficient effects can be obtained in terms of adhesion, etc. The active hydrogen equivalent is the value obtained by dividing the molecular weight of the amine curing agent by the number of hydrogen atoms in the amino group.

In the present invention, for such epoxy resin and amine curing agent, each material can be set and used so that the active hydrogen equivalent of the amine curing agent and the epoxy equivalent of the epoxy resin are preferably less than 0.4, more preferably 0.01 to 0.3, even more preferably 0.03 to 0.25, and particularly preferably 0.05 to 0.2, in terms of [active hydrogen equivalent of amine curing agent/epoxy equivalent of epoxy resin]. By using a combination of materials that satisfy these conditions as the epoxy resin and amine curing agent, more preferable effects can be obtained in terms of adhesion, etc.

The compounding ratio of epoxy resin to amine hardener is preferably set so that [(amount of amine hardener/active hydrogen equivalent of amine hardener)/(amount of epoxy resin/epoxy equivalent of epoxy resin)] is 1.0 or less, more preferably 0.3 to 1.0, even more preferably 0.5 to 0.98, particularly preferably 0.6 to 0.95, and most preferably 0.7 to 0.9. The amount and active hydrogen equivalent of the amine hardener, and the amount and epoxy equivalent of the epoxy resin are all based on the solid content. When the compounding ratio of epoxy resin to amine hardener is less than the above upper limit, it is suitable in terms of adhesion, base followability, suitability for topcoat materials, etc., and when it is more than the above lower limit, it is suitable in terms of curing property, adhesion, etc.

In the present invention, the pigment is a component that contributes to adhesion, etc. Examples of pigments that can be used include color pigments, extender pigments, and rust-preventive pigments.

Specific examples of color pigments include titanium oxide, zinc oxide, aluminum oxide, carbon black, graphite, black iron oxide, iron-chromium composite oxide, manganese-bismuth composite oxide, manganese-yttrium composite oxide, iron-manganese composite oxide, iron-copper-manganese composite oxide, iron-chromium-cobalt composite oxide, copper-chromium composite oxide, copper-manganese-chromium composite oxide, red iron oxide, molybdate orange, permanent red, permanent carmine, anthraquinone red, perylene red, quinacridone red, yellow iron oxide, titanium yellow, fast yellow, benzimidazolone yellow, chrome green, cobalt green, phthalocyanine green, ultramarine blue, Prussian blue, cobalt blue, phthalocyanine blue, quinacridone violet, dioxazine violet, aluminum pigments, and pearl pigments. These can be used alone or in combination of two or more.

Examples of extender pigments include heavy calcium carbonate, light calcium carbonate, kaolin, clay, china clay, diatomaceous earth, hydrous fine silica, talc, baryte powder, barium sulfate, precipitated barium sulfate, barium carbonate, magnesium carbonate, silica powder, aluminum hydroxide, etc. These can be used alone or in combination of two or more.

Examples of anti-rust pigments include phosphate compounds such as zinc phosphate, iron phosphate, aluminum phosphate, calcium phosphate, and magnesium phosphate; phosphate compounds such as zinc phosphite, iron phosphite, aluminum phosphite, calcium phosphite, and magnesium phosphite; polyphosphate compounds such as zinc polyphosphate, iron polyphosphate, and aluminum polyphosphate; molybdic acid compounds such as zinc molybdate, aluminum molybdate, calcium molybdate, barium molybdate, and aluminum phosphomolybdate; vanadium compounds such as vanadium oxide; boric acid compounds such as barium borate, barium metaborate, and calcium borate; cyanamide compounds such as zinc cyanamide and zinc calcium cyanamide, and one or more of these can be used.

The pigment volume concentration of the coating material of the present invention is 1 to 30%, preferably 3 to 25%, more preferably 5 to 23%, and particularly preferably 8 to 20%. By having the pigment volume concentration within the above range, it is possible to form a coating film with excellent adhesion while making use of the shape of the base. For example, if the base has an uneven pattern, the coating material can be applied evenly along the unevenness, making it possible to form a coating film with excellent finish, adhesion, etc. while making use of the uneven pattern. Furthermore, if the base is flat, a uniform coating film with smoothness can be formed, and excellent performance can be demonstrated in terms of adhesion, etc. If the pigment volume concentration does not satisfy the above value, it will be difficult to obtain the above-mentioned effects.

The pigment volume concentration is the volume percentage of the pigment contained in the dry coating film, and is a value calculated from the weight parts and specific gravity of the resin components (epoxy resin and amine hardener) that make up the coating material and the pigment. The specific gravity of the resin components is assumed to be 1.

Examples of non-aqueous solvents include aliphatic hydrocarbon solvents such as n-heptane, n-hexane, n-pentane, n-octane, n-nonane, n-decane, n-undecane, and n-dodecane; alicyclic hydrocarbon solvents such as methylcyclohexane and ethylcyclohexane; aliphatic hydrocarbon-containing mixed solvents such as mineral spirits; petroleum-based solvents such as petroleum ether, petroleum naphtha, solvent naphtha, and kerosene; as well as isoparaffin-based solvents, alcohol-based solvents, ether-alcohol-based solvents, ether-based solvents, ester-based solvents, ether-ester-based solvents, and ketone-based solvents. These can be used alone or in combination of two or more.

The coating material of the present invention contains a non-aqueous solvent with an aniline point of 12 to 70°C. Such a non-aqueous solvent contributes to improving adhesion by penetrating the substrate and slightly swelling or dissolving the existing coating film. Suitable non-aqueous solvents with an aniline point of 12 to 70°C include, for example, one or more selected from aliphatic hydrocarbon-containing mixed solvents such as mineral spirits, and petroleum-based solvents such as petroleum ether, petroleum naphtha, solvent naphtha, and kerosene. The aniline point is a value measured by the method of JIS K2256.

The coating material of the present invention may contain a silane compound in addition to the above components. In the present invention, the incorporation of a silane compound can further improve adhesion, etc.

Examples of the silane compound include tetrafunctional alkoxysilane compounds such as tetraethoxysilane, tetramethoxysilane, and tetrabutoxysilane;
trifunctional alkoxysilane compounds such as methyltrimethoxysilane, methyltriethoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltributoxysilane, propyltrimethoxysilane, propyltriethoxysilane, butyltrimethoxysilane, butyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, and phenyltributoxysilane;
bifunctional alkoxysilane compounds such as dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldibutoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, dipropyldimethoxysilane, dipropyldiethoxysilane, dibutyldimethoxysilane, dibutyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, diphenyldibutoxysilane, methylphenyldimethoxysilane, and methylphenyldiethoxysilane;
Chlorosilane compounds such as tetrachlorosilane, methyltrichlorosilane, ethyltrichlorosilane, propyltrichlorosilane, phenyltrichlorosilane, vinyltrichlorosilane, dimethyldichlorosilane, diethyldichlorosilane, diphenyldichlorosilane, and methylphenyldichlorosilane;
Acetoxysilane compounds such as tetraacetoxysilane, methyltriacetoxysilane, phenyltriacetoxysilane, dimethyldiacetoxysilane, and diphenyldiacetoxysilane;
silane compounds containing an epoxy group, such as γ-glycidoxypropyl trimexysilane, γ-glycidoxypropyl triethoxysilane, γ-glycidoxypropyl methyl dimethoxysilane, γ-glycidoxypropyl methyl diethoxysilane, γ-glycidoxypropyl triisopropenyloxysilane, γ-glycidoxypropyl triiminoxysilane, β-(3,4-epoxycyclohexyl)ethylmethyl dimethoxysilane, and an adduct of γ-isocyanatopropyl triisopropenyloxysilane and glycidol;
Silane compounds containing an amino group, such as N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, and γ-aminopropyltriethoxysilane;
Silane compounds containing a (meth)acryloxy group, such as γ-(meth)acryloxypropylmethyldimethoxysilane, γ-(meth)acryloxypropylmethyldiethoxysilane, γ-(meth)acryloxypropyltrimethoxysilane, and γ-(meth)acryloxypropyltriethoxysilane, can be used alone or in combination of two or more.

In the present invention, one or more compounds selected from the group consisting of silane compounds containing an epoxy group and silane compounds containing an amino group can be preferably used.

The mixing ratio of the silane compound is preferably 3% by weight or less, more preferably 0.1 to 2.8 parts by weight, and even more preferably 0.2 to 2.5 parts by weight, based on 100 parts by weight of the solid content of the resin components (epoxy resin and amine hardener). By using a mixing ratio of the silane compound within this range, adhesion can be further improved, and excellent adhesion can be exhibited not only when the epoxy resin and amine hardener are applied immediately after mixing, but also when the epoxy resin and amine hardener are applied after mixing and a certain amount of time has passed. The use of silane compounds is also suitable in terms of improving adhesion to existing coatings such as inorganic coatings, organic-inorganic composite coatings, and fluororesin coatings.

In addition to the above-mentioned components, the coating material of the present invention may contain, as necessary, for example, plasticizers, preservatives, antifungal agents, anti-algae agents, defoamers, leveling agents, pigment dispersants, surfactants, thickeners, anti-settling agents, anti-sagging agents, matting agents, catalysts, curing accelerators, UV absorbers, light stabilizers, antioxidants, etc., within the range in which the effects of the present invention are not significantly impaired.

The coating material of the present invention can be manufactured by uniformly stirring and mixing the above-mentioned components by conventional methods. When distributed, the coating material is preferably in the form of a two-part type consisting of a base agent containing an epoxy resin and a hardener containing an amine hardener, and these are mixed together when applied.

In a bending resistance test using a cylindrical mandrel method, the coating material of the present invention exhibits bending resistance with a mandrel diameter of 5 mm or less (preferably 4 mm or less, more preferably 3 mm or less). These characteristics improve the suitability for adhesion and conformability to a wide range of substrates, and can demonstrate sufficient performance even on substrates that include sealing joints, for example.

The cylindrical mandrel method is measured according to the method specified in JIS K5600-5-1:1999 "General Test Methods for Paints - Part 5: Mechanical Properties of Coatings - Section 1: Flex Resistance (Cylindrical Mandrel Method)". The test plate is a polished steel plate (SPCC-SB) with a thickness of 0.3 mm, brushed with a coating material so that the dry film thickness is 35 μm, and dried for 7 days under standard conditions (air temperature 23°C, relative humidity 50%). The test is performed under standard conditions using a type 1 test device, and the coating is visually inspected for cracks and peeling from the substrate. "Showing flex resistance with a mandrel diameter of a mm" means that when the test is performed using a mandrel with a diameter of a mm or more, no cracks or peeling from the substrate are observed.

Flex resistance can be set, for example, by the type and epoxy equivalent of the epoxy resin used, the type and active hydrogen equivalent of the amine curing agent, the compounding ratio of the epoxy resin to the amine curing agent, the pigment volume concentration, etc.

The non-volatile content of the coating material of the present invention is preferably 30 to 90% by weight, more preferably 40 to 80% by weight, and even more preferably 45 to 75% by weight. When the non-volatile content of the coating material is within such a range, the coating material can be applied evenly and uniformly to the base, which is preferable in terms of improving adhesion. In particular, when the base has an uneven pattern, the undercoat material can be applied evenly along the unevenness, making it possible to form a coating film that has excellent finish and adhesion while making use of the uneven pattern. The non-volatile content is a value measured by the method of JIS K5601-1-2, and the heating temperature is 105°C and the heating time is 60 minutes.

In the coating material of the present invention, the ratio of resin solids (total solids of epoxy resin and amine curing agent) in the non-volatile content of the coating material is preferably 20 to 85% by weight, more preferably 30 to 80% by weight, and even more preferably 40 to 75% by weight. The ratio of pigment in the non-volatile content of the coating material is preferably 15 to 80% by weight, more preferably 20 to 70% by weight, and even more preferably 25 to 60% by weight. By having the ratio of resin solids and pigment in the non-volatile content within the above ranges, it is possible to enhance the effect of forming a coating film with excellent adhesion while making use of the shape of the base.

The coating material of the present invention is preferably used as an undercoat material for painting the walls (inner wall surfaces, outer wall surfaces, etc.), floor surfaces, ceiling surfaces, etc. of buildings and civil engineering structures. Specifically, it is preferably used as an undercoat material applied to substrates such as mortar, concrete, ceramic siding boards, ceramic siding boards, metal siding boards, extrusion molding boards, slate boards, calcium silicate boards, ALC boards, metals, wood, glass, ceramics, synthetic resins, etc., or a wide variety of existing coating films formed on such substrates (substrate surfaces). The shapes of such substrates (substrates and existing coating films) include, for example, flat ones and ones with various uneven patterns (for example, stone-like, brick/tile-like, wood-grain-like, border-like, plastered wall-like, sprayed-on, etc.).

The coating material of the present invention can also be applied to a base that includes a sealing joint. Examples of the sealant that constitutes the sealing joint include silicone-based sealants, modified silicone-based sealants, polysulfide-based sealants, modified polysulfide-based sealants, acrylic urethane-based sealants, polyurethane-based sealants, SBR-based sealants, and butyl rubber-based sealants. The sealing joint may be made of an elastic dry joint material, etc.

The coating material of the present invention is preferably applicable to repairing (repainting) existing coating surfaces that have deteriorated over time. In other words, the coating material of the present invention is suitable as an undercoat material for repairing substrates with existing coatings, and can be used, for example, as an undercoat material when repairing siding boards with existing coatings. There are no particular limitations on the degree of deterioration of the existing coating surface over time, but any surface that has been used for approximately five years or more (even eight years or more) since the coating was formed can be used for painting.

If the existing coating surface to be painted includes a sealing joint, the existing sealant can be left as is, or new sealant can be applied before painting the coating material of the present invention.

The existing coating film is a coating film that has already been applied on the substrate by on-site painting or factory painting (line painting), and examples thereof include at least one type of coating film selected from organic coating films, inorganic coating films, and organic-inorganic composite coating films. Examples of the existing coating film include colored coating films (enamel coating films, printed coating films, etc.), clear coating films, and laminated coating films thereof, and are coating films formed by applying various coating materials to the substrate. Such coating materials may be, for example, any of room temperature drying type, room temperature curing type, bake curing type, ultraviolet (UV) curing type, and electron beam curing type.

Examples of binders for such coating materials include organic binders such as acrylic resin, polyurethane resin, epoxy resin, fluororesin, alkyd resin, and polyester resin, inorganic binders such as silicone resin, alkoxysilane, colloidal silica, and silicate, and organic-inorganic composite binders such as acrylic silicone resin.

The present invention can also be applied when the existing coating film is one or more selected from inorganic coating films (coating films containing the above-mentioned inorganic binder), organic-inorganic composite coating films (coating films containing the above-mentioned organic-inorganic composite binder), fluororesin coating films (coating films containing the above-mentioned fluororesin), etc. Such existing coating films may contain photocatalytic titanium oxide, etc.

When applying the coating material of the present invention, various methods can be used, such as brush coating, roller coating, spray coating, etc. Furthermore, when applying the coating in a factory, a roll coater, flow coater, etc. can also be used in addition to the above.

The coating material is preferably applied in an amount of about 0.03 to 0.5 kg/m ² (more preferably 0.05 to 0.3 kg/m ² ). The number of coats of the coating material may be appropriately determined depending on the condition of the substrate, but is preferably 1 to 2 coats. The drying temperature of the coating material is preferably -10 to 50°C, more preferably -5°C to 40°C. The coating material of the present invention is preferably of the room temperature curing type. The drying time after application of the coating material is preferably 1 hour or more, more preferably 2 hours or more and up to 14 days.

In the present invention, a topcoat material can be applied on the coating surface of the above-mentioned coating material. By applying the topcoat material, it is possible to protect the finished surface or improve the aesthetics. One or more types of topcoat materials can be used.

The coating film formed by the coating material of the present invention can exhibit excellent adhesion to a wide variety of topcoat materials. The topcoat material is not particularly limited as long as it is one that is generally used for painting buildings, etc., and examples of the binder include organic binders such as acrylic resin, polyurethane resin, epoxy resin, fluororesin, alkyd resin, and polyester resin, inorganic binders such as silicon resin, alkoxysilane, colloidal silica, and silicate, and organic-inorganic composite binders such as acrylic silicon resin.

In addition to the binders mentioned above, the components of the topcoat material include, for example, color pigments, extender pigments, thickeners, film-forming agents, leveling agents, wetting agents, plasticizers, antifreeze agents, pH adjusters, preservatives, antifungal agents, anti-algae agents, antibacterial agents, dispersants, defoamers, adsorbents, coupling agents, fibers, crosslinking agents, UV absorbers, light stabilizers, antioxidants, catalysts, solvents, water, etc.

Specific examples of topcoat materials include weather-resistant topcoat paints for architecture (JIS K5658:2010), weather-resistant paints for steel structures (JIS K5659:2008), glossy synthetic resin emulsion paints (JIS K5660:2008), fireproof paints for architecture (JIS K5661:1970), synthetic resin emulsion paints (JIS K5663:2008), road marking paints (JIS K5665:2011), multicolored pattern paints (JIS K5667:2003), synthetic resin emulsion pattern paints (JIS K5668:2010), acrylic resin-based non-aqueous dispersion paints (JIS K5670:2008), lead- and chromium-free rust-preventive paints (JIS K5674:2008), high solar reflectance paints for roofs (JIS K5675:2011), building floor paints (JIS K5970:2008), architectural waterproof coating materials (JIS A6021:2011), architectural finishing coating materials (JIS A6909:2014), etc.

The topcoat can be applied by known methods, such as brush painting, spray painting, roller painting, roll coating, flow coating, etc.

The following examples and comparative examples will clarify the features of the present invention.

○ Preparation of base agent (base agent 1)
75 parts by weight of epoxy resin a {dimer acid modified epoxy resin solution, solid content: 60% by weight, epoxy equivalent (per solid content): 780 g/eq, medium: mineral spirits (aniline point 42° C.) and solvent naphtha (aniline point 13° C.)}, 15 parts by weight of titanium oxide (specific gravity: 4.2), 2 parts by weight of talc (specific gravity 2.7), 4 parts by weight of solvent naphtha (same as above), and 4 parts by weight of additives (dispersant, thickener, and defoamer) were uniformly mixed in a conventional manner to produce main agent 1.

(Main agent 2)
67 parts by weight of epoxy resin a (same as above), 15 parts by weight of titanium oxide (same as above), 5 parts by weight of heavy calcium carbonate (specific gravity 2.7), 5 parts by weight of talc (same as above), 4 parts by weight of solvent naphtha (same as above), and 4 parts by weight of additives (dispersant, thickener, and defoamer) were uniformly mixed in a conventional manner to produce main agent 2.

(Main agent 3)
61 parts by weight of epoxy resin a (same as above), 15 parts by weight of titanium oxide (same as above), 8 parts by weight of heavy calcium carbonate (same as above), 8 parts by weight of talc (same as above), 4 parts by weight of solvent naphtha (same as above), and 4 parts by weight of additives (dispersant, thickener, and defoamer) were uniformly mixed in a conventional manner to produce main agent 3.

(Main agent 4)
Base component 4 was prepared by uniformly mixing 65 parts by weight of epoxy resin a (same as above), 29 parts by weight of solvent naphtha (same as above), and 6 parts by weight of additives (thickener and antifoaming agent) in a conventional manner.

(Main agent 5)
67 parts by weight of epoxy resin b {phenol novolac type bisphenol A epoxy resin solution, solid content: 60% by weight, epoxy equivalent (per solid content): 600 g/eq, medium: mineral spirits (aniline point 42° C.) and solvent naphtha (aniline point 13° C.)}, 15 parts by weight of titanium oxide (same as above), 5 parts by weight of heavy calcium carbonate (same as above), 5 parts by weight of talc (same as above), 4 parts by weight of solvent naphtha (same as above), and 4 parts by weight of additives (dispersant, thickener, and defoamer) were uniformly mixed in a conventional manner to produce base agent 5.

(Main agent 6)
38 parts by weight of epoxy resin a (same as above), 15 parts by weight of titanium oxide (same as above), 15 parts by weight of heavy calcium carbonate (same as above), 15 parts by weight of talc (same as above), 12 parts by weight of solvent naphtha (same as above), and 5 parts by weight of additives (dispersant, thickener, and defoamer) were uniformly mixed in a conventional manner to produce main agent 6.

○ Preparation of hardener (hardener 1)
Curing agent 1 was produced by uniformly mixing 15 parts by weight of an amine curing agent a {aliphatic polyamide amine, solid content 100% by weight, active hydrogen equivalent (solid content) 80 g/eq}, 4 parts by weight of a silane compound {N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane}, 16 parts by weight of an alcohol-based solvent, and 65 parts by weight of solvent naphtha (same as above) in a conventional manner.

(Curing agent 2)
Curing agent 2 was produced by uniformly mixing 15 parts by weight of amine curing agent a (same as above), 16 parts by weight of alcohol-based solvent, and 69 parts by weight of solvent naphtha (same as above) in a conventional manner.

(Hardening agent 3)
25 parts by weight of amine curing agent b {aliphatic polyamide amine, solid content 100% by weight, active hydrogen equivalent (solid content) 180 g/eq}, 4 parts by weight of silane compound (same as above), 11 parts by weight of alcohol-based solvent, and 60 parts by weight of solvent naphtha (same as above) were uniformly mixed in a conventional manner to produce curing agent 3.

(Hardening agent 4)
Curing agent 4 was produced by uniformly mixing 38 parts by weight of amine curing agent b (same as above), 6 parts by weight of alcohol-based solvent, and 56 parts by weight of solvent naphtha (same as above) in a conventional manner.

Example 1
The above-mentioned base agent 1 (100 parts by weight) and the above-mentioned curing agent 1 (25 parts by weight) were uniformly mixed to prepare a coating material of Example 1. The respective property values of this coating material are as shown in Table 1, and the compounding ratio of the epoxy resin and the amine curing agent [(amount of the amine curing agent/active hydrogen equivalent of the amine curing agent)/(amount of the epoxy resin/epoxy equivalent of the epoxy resin)] (represented as "compounding ratio" in Table 1) is 0.81, the pigment volume concentration is 8%, the non-volatile content of the coating material (represented as "non-volatile content" in Table 1) is 54% by weight, the ratio of the resin solid content in the non-volatile content of the coating material (represented as "resin ratio" in Table 1) is 72% by weight, and the ratio of the pigment in the non-volatile content of the coating material (represented as "pigment ratio" in Table 1) is 25% by weight, and the bending resistance is exhibited with a mandrel diameter of 2 mm or less in a bending resistance test by a cylindrical mandrel method (represented as "bending resistance" in Table 1).

Example 2
The base agent 2 (100 parts by weight) and the hardener 1 (20 parts by weight) were uniformly mixed to prepare a coating material of Example 2. The properties of this coating material are shown in Table 1.

Example 3
The base material 3 (100 parts by weight) and the hardener 1 (22 parts by weight) were uniformly mixed to prepare a coating material of Example 3. The properties of this coating material are shown in Table 1.

Example 4
The base material 2 (100 parts by weight) and the hardener 1 (23 parts by weight) were uniformly mixed to prepare a coating material of Example 4. The properties of this coating material are shown in Table 1.

Example 5
The base agent 2 (100 parts by weight) and the hardener 1 (30 parts by weight) were uniformly mixed to prepare a coating material of Example 5. The properties of this coating material are shown in Table 1.

Example 6
The base agent 2 (100 parts by weight) and the hardener 2 (20 parts by weight) were uniformly mixed to prepare a coating material of Example 6. The properties of this coating material are shown in Table 1.

(Example 7)
The base material 2 (100 parts by weight) and the hardener 3 (28 parts by weight) were uniformly mixed to prepare a coating material of Example 7. The properties of this coating material are shown in Table 1.

(Comparative Example 1)
The base agent 4 (100 parts by weight) and the hardener 3 (28 parts by weight) were uniformly mixed to prepare a coating material of Comparative Example 1. The properties of this coating material are shown in Table 1.

(Comparative Example 2)
The base material 5 (100 parts by weight) and the hardener 4 (24 parts by weight) were uniformly mixed to prepare a coating material of Comparative Example 2. The properties of this coating material are shown in Table 1.

(Comparative Example 3)
The base material 6 (100 parts by weight) and the hardener 4 (12 parts by weight) were uniformly mixed to prepare a coating material of Comparative Example 3. The properties of this coating material are shown in Table 1.

The following tests were carried out on each coating material obtained using the above methods.

Test 1
As the existing coating surface, a ceramic siding boat deteriorated by outdoor exposure (having tile-like convex and concave portions (joints) on the surface, an amorphous uneven pattern on the convex portions, and an inorganic clear coating as the outermost coating film) was prepared. This existing coating surface was placed vertically, and the above-mentioned coating material was spray-painted on the entire surface at a coating amount of 0.1 kg/ ^m2 , dried for 3 hours, and then spray-painted with a topcoat material (light brown acrylic silicone resin paint) at a coating amount of 0.2 kg/ ^m2 , and dried and cured for 7 days to prepare a test specimen. All painting and curing processes were carried out under standard conditions (temperature 23°C, relative humidity 50%).

The test specimens prepared by the above method were immersed in water for 7 days, after which cross-cuts were made in the coating at each location of the uneven pattern with a utility knife, and tape was applied to the cross-cut areas and then peeled off to evaluate adhesion. The evaluation was done on a four-point scale (A>B>C>D: poor), with "A" being a rating for no peeling at any location and "D" being a rating for significant peeling.

Test 2
As the existing coating surface, a ceramic siding board deteriorated by outdoor exposure (having tile-like convex and concave portions (joints) on the surface, with an irregular uneven pattern on the convex portions, and a fluororesin clear coating as the outermost coating layer) was prepared. Using this existing coating surface, a test specimen was prepared in the same manner as in Test 1, and the adhesion was evaluated.

Test 3
As an existing coating surface, a ceramic siding boat deteriorated by outdoor exposure (having tile-like convex and concave portions (joints) on the surface, with an irregular uneven pattern on the convex portions, and an acrylic resin coating as the outermost coating film) was prepared. Using this existing coating surface, a test specimen was prepared in the same manner as in Test 1, and the adhesion was evaluated.

Test 4
A test substrate was prepared by applying a polyurethane sealant to a thickness of 5 mm on a slate board. The coating material was applied to the test substrate with a brush at a coating amount of 0.1 kg/ ^m2 , dried for 3 hours, and then spray-painted with a topcoat material (light brown acrylic silicone resin paint) at a coating amount of 0.2 kg/ ^m2 , and dried and cured for 7 days to prepare a test specimen. All painting and curing processes were performed under standard conditions.

Cross-cuts were made with a cutter knife into the coating of the test specimens prepared by the above method, and tape was applied to the cross-cut areas and then peeled off to evaluate adhesion. The evaluation was done on a four-point scale (A>B>C>D: poor), with "A" being for no peeling and "D" being for significant peeling.

Test 5
Test specimens prepared in the same manner as in Test 4 above were subjected to a total of 10 cycles of hot and cold cycling tests, each cycle consisting of immersion in water for 18 hours, leaving at -20°C for 3 hours, and leaving at 50°C for 3 hours. The appearance of the coating was then checked and the occurrence of defects (blistering, peeling, cracks, etc.) was evaluated. The evaluation was done on a four-level scale (excellent: A>B>C>D: poor), with "A" indicating no defects and "D" indicating obvious defects.

The test results are shown in Table 2. The coating materials of Examples 1 to 7, and especially those of Examples 1 to 4, generally gave better results than those of Comparative Examples 1 to 3.

Claims (2)

A coating material comprising an epoxy resin, an amine curing agent, a pigment, and a non-aqueous solvent,
The epoxy resin contains a dimer acid-modified epoxy resin in an amount of 70 to 100% by weight in terms of solid content,
The amine curing agent has an active hydrogen equivalent (based on solid content) of 40 to 120 g/eq.
a compounding ratio of the epoxy resin to the amine curing agent, expressed as [(amount of the amine curing agent/active hydrogen equivalent of the amine curing agent)/(amount of the epoxy resin/epoxy equivalent of the epoxy resin)], is 0.3 to 1.0;
The non-aqueous solvent includes a non-aqueous solvent having an aniline point of 12 to 70° C., and the non-aqueous solvent is at least one selected from mineral spirits, petroleum ether, petroleum naphtha, solvent naphtha, and kerosene;
The pigment volume concentration is 1 to 19%,
A coating material characterized by exhibiting bending resistance in a bending resistance test using a cylindrical mandrel having a mandrel diameter of 5 mm or less. 2. The coating material according to claim 1, characterized in that the non-volatile content is 30 to 90% by weight.