JP6026939B2 - Room temperature curable coating composition - Google Patents

Description

  The present invention relates to a room temperature curable coating composition useful for construction, which is suitable for forming a coating film having excellent finish and sebum resistance.

  Conventionally, in the field of architectural paints, resins modified with unsaturated fatty acids have been widely used since a crosslinked coating film can be obtained even at room temperature.

  For example, in Patent Document 1, a urethane-modified vinyl resin obtained by further reacting a compound having an isocyanate group with a reaction product of an epoxy group-containing vinyl polymer and a fatty acid component containing an unsaturated fatty acid as a film-forming component. A room temperature curable coating composition is disclosed, and Patent Document 2 discloses a one-part curable coating composition for construction in which a specific amount of polymer dispersion is used in combination with the urethane-modified vinyl resin. Yes.

  According to these coating compositions, the initial drying property is good even under conditions of room temperature drying, and it is possible to form a coating film with excellent gloss and crack following properties.For example, when it is applied to a place where many people come and go, Ingredients such as hand fat and dirt adhere to the coating film over a long period of time and gradually permeate, and problems such as softening and peeling of the coating film (decrease in sebum resistance) may occur over time.

  On the other hand, in recent years, from the consideration of the human body or the environment, the use of paints using organic solvents with strong odors, so-called strong solvents, has been suppressed, and paints using so-called weak solvents with relatively little burden on the human body or the environment. Development is underway.

  In general, the solubility of a resin, which is a coating film forming component contained in a paint, in a weak solvent is much lower than the solubility in a strong solvent, which makes it difficult to design a weak solvent paint.

  For example, as a measure against the decrease in sebum resistance of the coating film, if a high-polarity material that is difficult to adjust to the sebum component is used as the coating film forming component, the solubility in a weak solvent decreases, resulting in poor finish of the coating film. Arise. Further, even if the amount of unsaturated fatty acid groups to be introduced into the coating film forming component is increased, the sebum resistance is not improved so much and the finish of the formed coating film becomes poor.

  Regarding such problems, Patent Document 3 discloses a one-part curable coating composition containing a polymer dispersion containing urethane bonds and unsaturated fatty acid groups and a polymer solution containing urethane bonds and unsaturated fatty acid groups in a specific ratio. However, Patent Document 4 discloses a one-part curable coating composition containing a modified resin having a dicyclopentenyl group, an unsaturated fatty acid group and a urethane bond.

  The coating compositions described in Patent Documents 3 and 4 can be diluted with a weak solvent, and can form a coating film excellent in finish and sebum resistance even under conditions of room temperature drying. When an object is applied a plurality of times, the paint film may be wrinkled, and there is a need for improvement.

JP 2001-329212 A JP 2001-262055 A JP 2009-114383 A JP 2009-114410 A

  The object of the present invention is to propose a room temperature curable coating composition suitable for forming a coating film that is less likely to cause a wrinkle phenomenon when applied multiple times and has excellent sebum resistance even under conditions of room temperature drying. It is in.

  As a result of intensive studies on the above-mentioned problems, the present inventors have obtained a coating film excellent in both sebum resistance and squeeze resistance at the time of coating by a composition containing a specific alkyd-modified acrylic resin and a specific amount of an amine compound. The inventors have found that it can also be obtained under conditions of room temperature drying, and have reached the present invention.

That is, the present invention
Alkyd-modified acrylic resin (A), polyaminoamide of unsaturated polycarboxylic acid, amino group-containing acrylic block copolymer, amino group-containing urethane polymer, and amino group-containing acrylic copolymer other than amino group-containing acrylic block copolymer A composition comprising a basic dispersant (B) selected from polymers and an organic solvent,
The alkyd-modified acrylic resin (A) has an acid component (a1) containing a drying oil fatty acid, a polyhydric alcohol component (a2) and a (meth) acrylate component (a3) as a copolymerization component,
The (meth) acrylate component (a3) contains (meth) acrylate having an alkyl group having 1 to 3 carbon atoms, (meth) acrylate having a hydroxyl group, and (meth) acrylate having a carboxyl group,
The total amount of (a1) and (a2) and the mass ratio [(a1) + (a2)] / a3 to (a3) are in the range of 1/99 to 50/50,
A room temperature curable coating composition, wherein the content of the basic dispersant (B) is in the range of 0.1 to 25% by mass based on the solid content mass of the alkyd-modified acrylic resin (A), A two-component room-temperature curable coating composition obtained by further blending a polyisocyanate compound with the room-temperature curable coating composition, a coating method for coating the one-component or two-component room-temperature curable coating composition,
About.

  According to the coating composition of the present invention, it is possible to form a cured coating film excellent in sebum resistance even under conditions of room temperature drying, and even when it is applied a plurality of times, the squeeze phenomenon is suppressed, so Even when it is applied to a place where it is touched again, a good coating state can be maintained for a long time.

  The coating composition of the present invention contains an alkyd-modified acrylic resin (A), a basic dispersant (B), a pigment, and an organic solvent. Hereinafter, it demonstrates in order.

<Alkyd-modified acrylic resin (A)>
The alkyd-modified acrylic resin (A) used as a coating film-forming component in the present invention comprises an acid component (a1), a polyhydric alcohol component (a2), and a (meth) acrylate component (a3) as a copolymerization component. .

<Acid component (a1)>
In the present invention, the acid component (a1) is a compound having a carboxyl group in the molecule, and includes a dry oil fatty acid as a part of the component. This is from the viewpoint of the room temperature drying property of the coating film.

  Such dry oil fatty acids are oxidatively curable fatty acids. Specific examples include fish oil fatty acids, dehydrated castor oil fatty acids, safflower oil fatty acids, linseed oil fatty acids, soybean oil fatty acids, sesame oil fatty acids, poppy oil fatty acids, enoys. Examples include oil fatty acid, hemp seed fatty acid, grape kernel oil fatty acid, corn oil fatty acid, tall oil fatty acid, sunflower oil fatty acid, cottonseed oil fatty acid, walnut oil fatty acid, rubber seed oil fatty acid, and the like. Can be used in combination.

  In addition, the acid component (a1) includes non-drying oil fatty acids such as coconut oil fatty acid, hydrogenated coconut oil fatty acid, and palm oil fatty acid; saturation such as caproic acid, capric acid, lauric acid, myristic acid, palmitic acid, and stearic acid. Fatty acids; dibasic acids such as phthalic anhydride, isophthalic acid, terephthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, succinic acid, fumaric acid, adipic acid, sebacic acid, maleic anhydride; benzoic acid, crotonic acid, p Monobasic acids such as -t-butylbenzoic acid; acid components other than dry oil fatty acids such as tribasic and higher polybasic acids such as trimellitic anhydride, methylcyclohexeric carboxylic acid and pyromellitic anhydride can be included. These can be used alone or in combination of two or more.

  As content of the drying oil fatty acid contained in an acid component (a1), the quantity of drying oil fatty acid is 1-40 mass% on the basis of alkyd modified acrylic resin (A) solid content mass, Preferably it is 3-35 mass%. Within range is desirable. It is from a viewpoint of the weather resistance and yellowing resistance of the coating film formed from this invention coating composition.

<Polyhydric alcohol component (a2)>
The polyhydric alcohol component (A2) is a compound having at least two hydroxyl groups in the molecule. For example, ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 3-methylpentanediol, 1 Dihydric alcohols such as 1,4-hexanediol and 1,6-hexanediol are mainly used, and if necessary, trihydric or higher polyhydric alcohols such as glycerin, trimethylolethane, trimethylolpropane, pentaerythritol are used. Can be used together. These polyhydric alcohols can be used alone or in admixture of two or more.

<(Meth) acrylate component (a3)>
The (meth) acrylate component (a3) in the present invention is a compound having a (meth) acryloyl group in the molecule, and examples of the compound having one (meth) acryloyl group in one molecule include methyl (meth) ) Acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl Linear or branched alkyl group-containing (meth) acryloyl monomers such as (meth) acrylate and stearyl (meth) acrylate; Cyclohexyl (meth) acrylate and alicyclic alkyl group-containing (meth) acryloyl such as isobornyl (meth) acrylate monomer Aralkyl group-containing (meth) acryloyl monomers such as benzyl (meth) acrylate; alkoxyalkyl group-containing (meth) acryloyl monomers such as 2-methoxyethyl (meth) acrylate and 2-ethoxyethyl (meth) acrylate; hexafluoroisopropyl (meth) ) Fluorine-containing (meth) acryloyl monomers such as acrylate, perfluorooctylmethyl (meth) acrylate, perfluorooctylethyl (meth) acrylate; amino group-containing (meth) acryloyl such as N, N-diethylaminoethyl (meth) acrylate Monomer; (meth) acrylamide; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, hydroxybutyl Hydroxyalkyl (meth) acrylates such as ru (meth) acrylate, ε-caprolactone modified products of the above hydroxyalkyl (meth) acrylates, and hydroxyl group-containing (meth) such as polyoxyethylene chain-containing (meth) acrylates whose molecular ends are hydroxyl groups Acryloyl monomer; carboxyl group-containing (meth) acryloyl monomer such as (meth) acrylic acid and β-carboxyethyl acrylate; carbonyl group-containing (meth) acryloyl monomer such as acetoacetoxyethyl (meth) acrylate and diacetone (meth) acrylamide; Glycidyl (meth) acrylate, β-methylglycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 3,4-epoxycyclohexylethyl (meth) acrylate, Epoxy group-containing (meth) acryloyl monomers such as 3,4-epoxycyclohexylpropyl (meth) acrylate; Isocyanato group-containing (meth) acryloyl monomers such as isocyanatoethyl (meth) acrylate; γ-methacryloyloxypropyltrimethoxysilane, γ -Alkoxysilyl group-containing (meth) acryloyl monomers such as methacryloyloxypropyltriethoxysilane; oxidative curing of dicyclopentenyloxyethyl (meth) acrylate, dicyclopentenyloxypropyl (meth) acrylate, dicyclopentenyl (meth) acrylate, etc. For example, an allyl group-containing (meth) acryloyl monomer such as allyl (meth) acrylate.

  In addition, as a compound having at least two (meth) acryloyl groups in one molecule, ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, 1, 3 -Butylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, 1,4-butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate , Pentaerythritol di (meth) acrylate, pentaerythritol tetra (meth) acrylate, glycerol di (meth) acrylate, 1,1,1-trishydroxymethylethanedi (meth) acrylate, 1,1,1-trishydride Carboxymethyl ethane tri (meth) acrylate, 1,1,1-trishydroxymethylpropane tri (meth) acrylate.

  These (meth) acrylate components can be used alone or in combination of two or more.

  Moreover, the said (meth) acrylate component (a3) can use together other polymerizable unsaturated monomer copolymerizable with this (a3) component.

  Examples of such other polymerizable unsaturated monomers include (meth) acrylonitrile; vinyl ester compounds such as vinyl acetate and vinyl propionate; vinyl aromatic compounds such as styrene and α-methylstyrene; triallyl isocyanurate and diallyl terephthalate. , Polyvinyl compounds having at least two polymerizable unsaturated groups in one molecule such as divinylbenzene; allyl alcohol; carboxyl group-containing polymerizable unsaturated monomers such as maleic acid and crotonic acid; (meth) acrolein, formylstyrene Carbonyl ketones having 4 to 7 carbon atoms (for example, vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone, etc.), carbonyl group-containing polymerizable unsaturated monomers such as acetoacetoxyallyl ester, epoxy groups such as allyl glycidyl ether, etc. Polymerizable unsaturated monomers; isocyanato group-containing polymerizable unsaturated monomers such as m-isopropenyl-α, α-dimethylbenzyl isocyanate; alkoxysilyl group-containing polymerizable unsaturated monomers such as vinyltrimethoxysilane and vinyltriethoxysilane; Fluorovinyl ethers such as fluoroalkyl trifluorovinyl ether and perfluoroalkyl trifluorovinyl ether; Oxygen-curable group-containing polymerization of epoxy group-containing polymerizable unsaturated monomer or reaction product of hydroxyl-containing polymerizable unsaturated monomer and unsaturated fatty acid Unsaturated unsaturated monomers and the like, and these can be used alone or in combination of two or more.

  In the present invention, the (meth) acrylate component (a3) has a (meth) acrylate having a C 1-3 alkyl group, a (meth) acrylate having a hydroxyl group, and a carboxyl group as part of the component ( It has a (meth) acrylate.

  This is because the sebum softening resistance of the coating film formed using the composition of the present invention with these monomers is improved.

Examples of the (meth) acrylate having an alkyl group having 1 to 3 carbon atoms include methyl (meth) acrylate, ethyl (meth) acrylate, and propyl (meth) acrylate, and these may be used alone or in combination of two or more. Can be used.
As the (meth) acrylate having a hydroxyl group, hydroxyalkyl (meth) such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and hydroxybutyl (meth) acrylate Examples include acrylates, ε-caprolactone modified products of the above hydroxyalkyl (meth) acrylates, polyoxyethylene chain-containing (meth) acrylates whose molecular ends are hydroxyl groups, and these may be used alone or in combination of two or more. it can.
Examples of the (meth) acrylate having a carboxyl group include (meth) acrylic acid and β-carboxyethyl acrylate, and these can be used alone or in combination of two or more.

Preferable contents of (meth) acrylate having an alkyl group having 1 to 3 carbon atoms, (meth) acrylate having a hydroxyl group, (meth) acrylate having a carboxyl group, and other (meth) acrylates are (meth) acrylate. 2 to 50% by mass, preferably 4 to 35% by mass of (meth) acrylate having an alkyl group having 1 to 3 carbon atoms based on the total mass of component (a3),
0.5 to 15% by mass, preferably 0.5 to 10% by mass of (meth) acrylate having a hydroxyl group,
0.2 to 5% by mass of (meth) acrylate having a carboxyl group, preferably 0.2 to 3% by mass,
It is suitable from the viewpoint of softening of sebum and solubility in organic solvents, particularly weak solvents, containing other (meth) acrylates in the range of 30 to 97.3% by mass, preferably 52 to 95.3% by mass. ing.

  In the alkyd-modified acrylic resin (A), the degree of modification of the alkyd resin, that is, the mass ratio [(a1) + (a2)] / a3 of the total amount of (a1) and (a2) and (a3) is It is within the range of 1/99 to 50/50, and preferably within the range of 10/90 to 40/60.

  If the mass ratio of (a1) + (a2) is too small, that is, if the amount of alkyd modification is small, the solubility of the coating composition of the present invention in the solvent is reduced, and the curability is insufficient and the sebum softening resistance is satisfied. I can't do it. On the other hand, when the mass ratio of (a1) + (a2) is too large, that is, when the amount of alkyd modification is too large, the weather resistance of the coating film is lowered, and yellowing, darkness or injury may occur.

  The alkyd-modified acrylic resin (A) having the above (a1) to (a3) as a copolymerization component is obtained by a known method. For example, an alkyd produced using the components (a1) and (a2) Resin is used to modify resin or alkyd resin obtained by reacting a carboxyl group or hydroxyl group of this resin with an acrylic resin having a reactivity with these groups, such as carboxyl group, hydroxyl group or epoxy group. Examples thereof include a modified resin obtained by graft polymerization of a polymerizable unsaturated monomer component containing an acrylate component (a3) using a peroxide polymerization initiator.

  The alkyd-modified acrylic resin (A) preferably has solubility in a weak solvent.

  “Weak solvent” is a well-known term in the art, and generally means a solvent having a weak dissolving power. The weak solvents include those listed as the third type organic solvents in the classification of organic solvents according to the Industrial Safety and Health Act. Examples of Class 3 organic solvents include gasoline, kerosene, coal tar naphtha (including solvent naphtha), petroleum ether, petroleum naphtha, petroleum benzine, turpentine oil, mineral spirit (mineral thinner, petroleum spirit, white spirit and mineral turpentine Are included).

  The weak solvent is commercially available, and examples of the weak solvent commercial products include “Swazole 1000” and “Swazole 1500” (manufactured by Maruzen Petroleum Co., Ltd.), “Solvesso 150”, “Solvesso 200”, “HAWS”. ”And“ LAWS ”(manufactured by Shell Japan),“ Essonaphtha No. 6 ”and“ Exor D30 ”(trade name, manufactured by ExxonMobil Chemical Co., Ltd.),“ Pegasol 3040 ”(trade name, manufactured by ExxonMobil Chemical Co., Ltd.) , “A Solvent”, “Clensol” and “Ipsol 100” (made by Idemitsu Kosan Co., Ltd.), “Mineral Spirit A”, “High Aroma 2S” and “High Aroma 2S” (above, Shin Nippon Petrochemical Co., Ltd.), “ “Linearene 10” and “Linearene 12” (made by Idemitsu Petrochemical Co., Ltd.), “Rikasolv 900”, Rikasorubu 910B "and" Rikasorubu 1000 "(or more, New Japan Chemical Co., Ltd.), and the like.

  The alkyd-modified acrylic resin (A) can be produced by reacting the above components in the presence of the weak solvent or in the presence of the weak solvent and other organic solvents.

The weight average molecular weight of the alkyd-modified acrylic resin (A) is not particularly limited, but is generally 10,000 from the viewpoints of sebum softening resistance, double coating workability, and solubility in a weak solvent. It is desirable to be in the range of ˜120,000 and preferably in the range of 15,000 to 80,000.

  In this specification, the weight average molecular weight is the retention time (retention capacity) of a standard polystyrene having a known molecular weight measured under the same conditions as the retention time (retention capacity) measured using a gel permeation chromatograph (GPC). Is a value obtained by converting to a molecular weight of polystyrene.

<Basic dispersant (B)>
The second feature of the coating composition of the present invention is that it contains a basic dispersant (B).

  Although the reason is not clear, the inclusion of the basic dispersant (B) has the effect of remarkably improving the squeezing phenomenon of the coating film that often occurs when the paint is applied a plurality of times.

  Various basic polymer dispersants can be used as the basic dispersant, and in particular, known polymer dispersants having an N atom-containing polar group can be widely used as basic dispersants.

  Examples of the N atom-containing polar group include an amino group, an aminoamide group, pyridine, pyrimidine, and pyrazine.

  The amine value per solid content of the basic dispersant (B) can be in the range of 3 to 400 mgKOH / g, preferably 20 to 400 mgKOH / g.

  The amine value indicates the total amount of basic groups 1, 2, and tertiary amines, and is expressed in mg of KOH equivalent to hydrochloric acid required to neutralize all basic groups in 1 g of a sample. Is.

  The said basic dispersing agent (B) can be manufactured by a well-known method, and is marketed. Specifically, a copolymer having an amino group-containing (meth) acryloyl monomer as described above as a copolymerization component, DisperBYK series (from BYK Chemie), EFKA series (from Fuka Additive), Solsperse series ( The above can be used alone or in combination of two or more types.

  In the present invention, the content of the basic dispersant (B) is in the range of 0.1 to 25% by mass, preferably 0.3%, based on the solid content mass of the alkyd-modified acrylic resin (A). It is suitable to be in the range of ˜25% by mass.

  When the content of the basic dispersant (B) is within this range, the sebum softening resistance of the coating film can be good.

<Pigment>
As the pigment contained in the coating composition of the present invention, conventionally known pigments can be used without limitation, and specifically, coloring pigments such as titanium oxide, bengara, cyanine-based color pigment, carbon black, zircon powder; Extender pigments such as silica, barita powder, precipitated barium sulfate, barium carbonate, calcium carbonate, gypsum, clay, white carbon, diatomaceous earth, talc, magnesium carbonate, alumina white, gloss white, tancal, etc .; These can be used alone or in combination.

<Organic solvent>
The coating composition of the present invention is based on an organic solvent, and the organic solvent that can be contained is not particularly limited, but it is possible to contain a large amount of a weak solvent having a low dissolving power.

  Specifically, the content of the weak solvent contained in the coating composition can be in the range of 50% by mass or more, particularly 70% by mass or more based on the total organic solvent.

  Also, known organic solvents other than weak solvents can be used. Examples of the other organic solvents include hydrocarbons such as n-butane, n-hexane, n-heptane, n-octane, cyclopentane, cyclohexane, and cyclobutane. Solvents; aromatic solvents such as toluene and xylene; ketone solvents such as methyl isobutyl ketone; n-butyl ether, dioxane, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol Ether solvents such as ethyl acetate, n-butyl acetate, isobutyl acetate, ethylene glycol monomethyl ether acetate, butyl carbitol acetate and other ester solvents; methyl ethyl ketone, methyl iso Ethyl ketone, ketone solvents such as diisobutyl ketone; ethanol, isopropanol, n- butanol, sec- butanol, alcohol solvents such as isobutanol; and combinations thereof.

<Polyurethane resin>
A polyurethane resin (C) can be included in the coating composition of the present invention as necessary from the viewpoint of physical properties of the coating film. From the viewpoint of physical properties of the coating film.

  Examples of the polyurethane resin (C) include resins having urethane bonds obtained from various polyol components such as acrylic polyol, polyester polyol, polyether polyol, and polycarbonate polyol and a polyisocyanate compound.

  Examples of the polyisocyanate compound include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, and mixtures thereof, diphenylmethane-4,4′-diisocyanate, diphenylmethane-2,4′-diisocyanate, and mixtures thereof, naphthalene. -1,5-diisocyanate, 3,3′-dimethyl-4,4′-biphenylene diisocyanate, xylylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, hydrogenated xylylene diisocyanate, etc. it can.

  When blending the polyurethane resin (C), the blending amount is (A) / (C) = 99.5 / 0.5 to the alkyd-modified acrylic resin (A) / polyurethane resin (C) solid content mass ratio. It can be in the range of 60/40, preferably 99.5 / 0.5 to 70/30.

<Coating composition>
The coating composition of the present invention comprises a modifying resin; an additive such as a curing agent, a curing catalyst, an antifungal agent, an anti-settling agent, a pigment dispersant, an antifoaming agent, an anti-skinning agent, and a coating surface conditioner. It can mix | blend as needed.

Among these, as the curing catalyst, a catalyst that promotes oxidative curing, a so-called metal dryer, specifically a metal salt of a fatty acid, a metal oxide, a single metal, or the like can be used.
The fatty acid of the metal salt of the fatty acid includes octylic acid, naphthenic acid, neodecanoic acid, butyric acid, caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, ligrinoceric acid, Serotic acid, montanic acid, melissic acid, succinic acid, lindelic acid, tuzuic acid, succinic acid, myristoleic acid, zomarinic acid, petroceric acid, oleic acid, vaccenic acid, gadoleic acid, whale oil, erucic acid, shark oil Acid, linoleic acid, hiragoic acid, eleostearic acid, bunicic acid, tricosanoic acid, linolenic acid, moloctic acid, parinaric acid, arachidonic acid, sardine acid, hiragacic acid, nisinic acid, soybean oil fatty acid, stearic acid, tall oil fatty acid Etc.

  Examples of the fatty acid metal salt include salts of a metal such as cobalt, manganese, zirconium, lithium, barium, zinc, copper, iron, calcium, magnesium, cerium, aluminum, and strontium with a fatty acid. These can be used alone or in combination of two or more.

  As the metal dryer, in addition to the metal salt of the fatty acid, one or more of the simple metals and oxides exemplified above can be used.

  The content of the active ingredient in the metal dryer is 0.05 to 10% by mass, preferably 0.1 to 5.0% by mass, based on the solid content mass of the alkyd-modified acrylic resin (A). Is suitable from the viewpoint of the sebum softening resistance of the coating film and the two-time coating workability.

  In the present invention, there is provided a two-pack type room temperature curable coating composition obtained by further blending a polyisocyanate compound with the room temperature curable coating composition obtained as described above.

  This is because by adding the polyisocyanate compound, the sebum softening resistance of the formed coating film can be further improved.

  As a polyisocyanate compound, it is a compound which has two or more free isocyanate groups in 1 molecule, A conventionally well-known thing can be used without a restriction | limiting. Examples include aliphatic polyisocyanate compounds, alicyclic polyisocyanate compounds, araliphatic polyisocyanate compounds, aromatic polyisocyanate compounds, and derivatives of these polyisocyanate compounds.

  Examples of the polyisocyanate compound derivative include dimer, trimer, burette, allophanate, carbodiimide, uretdione, uretoimine, isocyanurate, oxadiazine trione, polymethylene polyphenyl polyisocyanate (crude MDI, polymeric MDI). ), Crude TDI and the like. These polyisocyanate compounds and derivatives thereof may be used alone or in combination of two or more.

  The polyisocyanate compound is stored separately from the component (main component) containing the alkyd-modified acrylic resin (A), and is used by mixing before coating. The use ratio is the hydroxyl group 1 contained in the main component. It is possible to adjust the equivalent ratio of isocyanate groups contained in the polyisocyanate compound to 0.3 to 10, preferably 0.5 to 7.0, so that the sebum resistance of the coating film is softened. From the viewpoints of workability and workability for two-time coating.

  The coating composition of the present invention can be cured at room temperature, and the cured product exhibits excellent performance, but may be forced-dried or heat-cured.

  The coated surface to which the coating composition of the present invention is applied is a metal material surface that has been subjected to a ground treatment as necessary, for example, iron, steel plate surface, galvanized surface, stainless steel surface, aluminum surface, and the like. The old paint film surface can be mentioned, but it can also be applied to materials such as concrete, mortar, slate, slate roof tiles, ceramic base materials, plastic materials, and old paint film surfaces. Is possible.

  Although the use is not particularly limited, it is suitable for metal surface coating applications such as buildings, doors of structures, handrails, and piping.

  The coating composition of the present invention can be applied by a known means such as spray coating, roller coating, brush coating, flow coating, etc. after dilution to the coating viscosity as necessary.

  In applying the coating composition of the present invention, a known undercoat or topcoat may be applied depending on the condition of the article to be coated and the coating environment.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to only these examples. In the following examples, “part” and “%” mean “part by mass” and “% by mass”, respectively.

<Production of alkyd-modified acrylic resin solution>
Production Example 1
In the reaction vessel, 36.5 parts of the following alkyd resin solution (*) (solids 23.7 parts) and 23 parts of “Swazole 1000” (trade name, manufactured by Maruzen Petrochemical Co., Ltd., aromatic hydrocarbon solvent) are blended. The temperature was raised to 120 ° C. while stirring.
Subsequently, the following monomer composition and initiator solution were dropped over 3 hours, respectively, while the liquid in the reaction vessel was maintained and stirred at the same temperature, and reacted.
Thereafter, the mixture was cooled and diluted with SWAZOL 1000 until the solid content became 55% to obtain an alkyd-modified acrylic resin solution (A-1). The weight average molecular weight was 50000.
(Monomer composition)
Styrene 23 parts methyl methacrylate 17.7 parts 2-ethylhexyl acrylate 10 parts i-butyl methacrylate 22.5 parts hydroxyethyl methacrylate 2.3 parts acrylic acid 0.8 parts (initiator solution)
Tertiary butyl peroxide 5 parts “Swazole 1000” 10 parts (*) Alkyd resin solution: soybean oil fatty acid / phthalic anhydride / pentaerythritol / glycerin = 477 parts / 147 parts / 133 parts / 4 parts, diluted solvent “Swazole 1000” ”65% solids.

Production Examples 2-12
In the above production examples, acrylic modified alkyd resin solutions (A-2) to (A-12) were obtained in the same manner as in Production Example 1 except that the monomer composition was as shown in the following table.

<Manufacture of weak solvent coating composition>
Examples 1-21 and Comparative Examples 1-6
A one-component weak solvent-based paint composition and two-component weak solvent-based paint compositions (I-1) to (I-27) were obtained with the following composition. Table 2 shows the actual formulation.

(Note 1) Basic dispersant (B-1): polyaminoamide solution of unsaturated polycarboxylic acid having an amine value of 190, solid content of 50%,
(Note 2) Basic dispersant (B-2): Amino group-containing acrylic block copolymer solution having an amine value of 56, solid content of 80%,
(Note 3) Basic dispersant (B-3): Amino group-containing urethane polymer solution having an amine value of 30, a solid content of 35%,
(Note 4) Basic dispersant (B-4): Amino group-containing acrylic copolymer solution having an amine value of 36, solid content of 70%,
(Note 5) Basic dispersant (B-5): Amino group-containing acrylic block copolymer solution having an amine value of 57, solid content 52%,
(Note 6) Basic dispersant (B-6): Amino group-containing acrylic copolymer solution having an amine value of 18, solid content 50%,
(Note 7) Polyisocyanate compound: HMDI isocyanurate having an NCO content of 17 to 18%.

<Performance test>
Each weak solvent coating composition obtained in the above Examples and Comparative Examples was subjected to the following performance test. The results are shown in Table 2.
(1) Sebum softening resistance test: Each coating composition was applied on a steel plate treated with zinc phosphate with a 200 μm applicator and then left at 40 ° C. and 75% RH for 1 month. Test mixed solution of oleic acid / salad oil = 30/70 (mass%) was brought into contact with the coating film at a rate of 30 g / m ² for 3 days, the test solution was removed, and the coating film state after rubbing with a finger Was observed.
A: No problem,
○: A part of the coating film is slightly softened but is not sticky when touched by hand.
Δ: The entire coating film is softened.
X: The whole coating film peels.
(2) Two-time coating workability: After coating each coating composition on a glass plate with a 300 μm applicator, the coating composition was left at 40 ° C. and 75% RH for 7 days, and each coating composition was once again formed on the obtained coating film. The state of the coating film after the object was coated with a brush to a dry film thickness of 20 to 40 μm was observed.
○: No abnormality
Δ: Chijimi is slightly recognized in the coating film,
X: Significant wrinkles are observed in the coating film
(3) Gel fraction: Each composition was coated with a 150 μm applicator, and then the extraction rate (%) after immersion in xylene for 1 day after standing for 1 month at 40 ° C. and 75% RH was examined.

Claims (7)

Alkyd-modified acrylic resin (A), polyaminoamide of unsaturated polycarboxylic acid, amino group-containing acrylic block copolymer, amino group-containing urethane polymer, and amino group-containing acrylic copolymer other than amino group-containing acrylic block copolymer A composition comprising a basic dispersant (B) selected from polymers and an organic solvent,
The alkyd-modified acrylic resin (A) has an acid component (a1) containing a drying oil fatty acid, a polyhydric alcohol component (a2) and a (meth) acrylate component (a3) as a copolymerization component,
The (meth) acrylate component (a3) contains (meth) acrylate having an alkyl group having 1 to 3 carbon atoms, (meth) acrylate having a hydroxyl group, and (meth) acrylate having a carboxyl group,
The total amount of (a1) and (a2) and the mass ratio [(a1) + (a2)] / a3 to (a3) are in the range of 1/99 to 50/50,
A room-temperature-curable coating composition, wherein the content of the basic dispersant (B) is in the range of 0.1 to 25% by mass based on the solid content mass of the alkyd-modified acrylic resin (A). The (meth) acrylate component (a3) is based on the total mass of the (meth) acrylate component (a3),
2 to 50% by mass of (meth) acrylate having an alkyl group having 1 to 3 carbon atoms,
0.5 to 15% by mass of (meth) acrylate having a hydroxyl group,
0.2 to 5 mass% of (meth) acrylate having a carboxyl group,
30 to 97.3 mass% of other (meth) acrylates,
The room temperature curable coating composition according to claim 1, which is contained within the range of   The room temperature curable coating composition according to claim 1 or 2, wherein the amine value per solid content of the basic dispersant (B) is in the range of 3 to 400 mgKOH / g.   The room temperature curable coating composition according to any one of claims 1 to 3, further comprising a urethane resin (C).   The room temperature curable coating composition according to any one of claims 1 to 4, further comprising a metal dryer.   A two-pack type room temperature curable coating composition obtained by further blending a polyisocyanate compound with the room temperature curable coating composition according to any one of claims 1 to 5.   The coating method which coats the to-be-coated surface with the one-component or two-component room temperature curable coating composition according to any one of claims 1 to 6.