JP2016130292A - Plastisol composition, and chipping-resistant coating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plastisol composition excellent in storage stability and low temperature curability, and to provide a chipping-resistant coating material.SOLUTION: The plastisol composition contains: an adhesiveness imparting agent (J) which contains a block polyisocyanate compound (c) being a reaction product of a blocking agent (a) with a polyisocyanate compound (b), a compound (e) having two or more active hydrogen groups in one molecule thereof, a blocked polyisocyanate dissociation catalyst (f) and a strong acid (g) having an acid dissociation constant (pKa) equal to or lower than 2; a thermoplastic resin (K) and a plasticizer (L). It is preferable that the adhesiveness imparting agent (J) comprises: a principal agent (D) containing a blocked polyisocyanate compound (c); and a curing agent (H) which contains the compound (e) having two or more active hydrogen groups, the blocked polyisocyanate dissociation catalyst (f) and the strong acid (g) having the acid dissociation constant (pKa) equal to or lower than 2.SELECTED DRAWING: None

Description

  The present invention relates to plastisol compositions and chipping resistant coatings. More particularly, the present invention relates to a plastisol composition and a chipping-resistant coating material that are coated on an outer plate of an automobile and prevent corrosion of a car body steel plate.

  Conventionally, various plastisols for coating are usually blended with an adhesiveness imparting agent in order to improve the adhesion to an object to be coated. Among them, the adhesion-imparting agent for chipping-resistant paints coated on automotive steel sheets contains a base agent and a curing agent as a base, and a main component is a reaction between a polyol and a polyisocyanate compound. A resulting blocked product of an isocyanate group-terminated urethane prepolymer is known (see, for example, Patent Document 1). However, when the adhesiveness-imparting agent described in Patent Document 1 is used, the adhesion to a metal-coated surface, paintability (coating appearance) and chipping resistance are excellent, but the storage stability and low-temperature curability of plastisol are sufficiently satisfactory. It wasn't possible.

JP-A-7-26096

  An object of the present invention is to provide a plastisol composition and a chipping-resistant coating material that are excellent in storage stability and low-temperature curability.

  The inventor of the present invention has arrived at the present invention as a result of intensive studies to solve the above problems. That is, the present invention relates to a blocked polyisocyanate compound (c) which is a reaction product of a blocking agent (a) and a polyisocyanate compound (b), a compound (e) having two or more active hydrogens in the molecule, a block A plastisol composition containing an adhesion-imparting agent (J) containing a polyisocyanate dissociation catalyst (f) and a strong acid (g) having an acid dissociation constant (pKa) of 2 or less, a thermoplastic resin (K), and a plasticizer (L) A chipping-resistant paint containing the plastisol composition; a chipping-preventing steel sheet having a cured product of the chipping-resistant paint on at least a part of the steel sheet surface.

  The plastisol composition of the present invention is excellent in both storage stability and low-temperature curability.

  The plastisol composition of the present invention comprises a blocked polyisocyanate compound (c) which is a reaction product of a blocking agent (a) and a polyisocyanate compound (b), a compound having two or more active hydrogens in the molecule (e ), A block polyisocyanate dissociation catalyst (f) and an adhesion promoter (J) containing a strong acid (g) having an acid dissociation constant (pKa) of 2 or less, a thermoplastic resin (K), and a plasticizer (L) To do.

Adhesiveness imparting agent (J)
The adhesion-imparting agent (J) is a blocked polyisocyanate compound (c) which is a reaction product of the blocking agent (a) and the polyisocyanate compound (b), a compound having two or more active hydrogens in the molecule (e ), A block polyisocyanate dissociation catalyst (f) and a strong acid (g) having an acid dissociation constant (pKa) of 2 or less.

Examples of the compound (e) having two or more active hydrogens in the molecule include polyol (e1), polyamine (e2), alkanolamine (e3), and a mixture of two or more thereof.

Polyol (e1)
Polyols include polyether polyol (e11), polyester polyol (e12), acrylic polyol (e13), polyolefin polyol (e14), fluorine polyol (e15), polycarbonate polyol (e16), polyurethane polyol (e17), and these The mixture of 2 or more types is mentioned.

The polyether polyol and (e11) include an active hydrogen compound such as aliphatic amine, aromatic amine, Mannich polyol, polyhydric alcohol, polyhydric phenol, bisphenol, alicyclic amine, heteroalicyclic amine, and Compounds obtained by adding alkylene oxides having 2 to 4 carbon atoms (hereinafter sometimes abbreviated as AO) to them, that is, aliphatic amine polyol (e111), aromatic amine polyol (e112), Mannich polyol (e113), many Examples thereof include monohydric alcohol (e114), polyhydric phenol (e115), bisphenols (e116), alicyclic amine (e117), and heteroalicyclic amine (e118). These polyether polyols may be a mixture of two or more.

Examples of the aliphatic amine polyol (e111) include alkylenediamine-based polyols and alkanolamine-based polyols. These polyol compounds are polyfunctional polyol compounds having terminal hydroxyl groups obtained by ring-opening addition of at least one cyclic ether such as ethylene oxide and propylene oxide using alkylene diamine or alkanol amine as an initiator. As the alkylene diamine, known compounds can be used without limitation. Specifically, use of alkylene diamine having 2 to 8 carbon atoms such as ethylene diamine, propylene diamine, butylene diamine, hexamethylene diamine, and neopentyl diamine is preferable. Among these, the use of alkylenediamine having a small number of carbon atoms is more preferable, and the use of a polyol compound having ethylenediamine or propylenediamine as an initiator is particularly preferable. Examples of the alkanolamine include monoethanolamine, diethanolamine, and triethanolamine. The number of functional groups of the polyol compound using alkylenediamine as the initiator is 4, the number of functional groups of the polyol compound using alkanolamine as the initiator is 3, and the number of functional groups in these mixtures is 3 to 4. The hydroxyl value of the aliphatic amine polyol is usually 100 to 1500 mgKOH / g, preferably 200 to 1200 mgKOH / g. These aliphatic amine polyols may be a mixture of two or more.

The aromatic amine polyol (e112) is a polyfunctional polyether polyol compound having a terminal hydroxyl group obtained by ring-opening addition of at least one cyclic ether such as ethylene oxide or propylene oxide using an aromatic diamine as an initiator. As the initiator, known aromatic diamines can be used without limitation. Specific examples include 2,4-toluenediamine, 2,6-toluenediamine, diethyltoluenediamine, 4,4'-diaminodiphenylmethane, p-phenylenediamine, o-phenylenediamine, naphthalenediamine and the like. Among these, use of toluenediamine (2,4-toluenediamine, 2,6-toluenediamine or a mixture thereof) is particularly preferable. The number of functional groups of the aromatic amine polyol is 4, and the hydroxyl value is usually 100 to 1500 mgKOH / g, preferably 200 to 1200 mgKOH / g. These aromatic amine polyols may be a mixture of two or more.

Mannich polyol (e113) is a ring-opening addition polymerization of at least one of ethylene oxide and propylene oxide to an active hydrogen compound obtained by the Mannich reaction of phenol and / or its alkyl-substituted derivative, formaldehyde and alkanolamine, or this compound. Is a polyol compound having a hydroxyl value of 200 to 700 mgKOH / g and having 2 to 4 functional groups. As a commercial item of Mannich polyol, DK-3773, DK-3776, DK-3801, DK-3810, DK-3820 (Daiichi Kogyo Seiyaku) etc. are mentioned, for example. These Mannich polyols may be a mixture of two or more.

The polyhydric alcohol (e114) is a dihydric alcohol (for example, ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, dipropylene glycol, neopentyl glycol, etc.) Trivalent or higher alcohols (for example, glycerin, trimethylolpropane, pentaerythritol, methyl glucoside, sorbitol, sucrose, etc.) and the like. These polyhydric alcohols may be a mixture of two or more.

Examples of the polyhydric phenol (e115) include pyrogallol and hydroquinone. Examples of bisphenols include bisphenol A, bisphenol S, bisphenol F, and low condensation products of phenol and formaldehyde. Examples of the alicyclic amine include isophorone diamine and cyclohexylene diamine. Examples of the heterocyclic amine include aminoethylpiperazine.

As the polyester polyol (e12), for example, a dibasic acid selected from the group of carboxylic acids such as succinic acid, adipic acid, sebacic acid, dimer acid, maleic anhydride, phthalic anhydride, isophthalic acid, terephthalic acid alone or Polyester polyols obtained by a condensation reaction of a mixture and a polyhydric alcohol selected from the group of ethylene glycol, propylene glycol, diethylene glycol, neopentyl glycol, trimethylolpropane, glycerin and the like alone or a mixture, and, for example, a polyhydric alcohol And polycaprolactones obtained by ring-opening polymerization of ε-caprolactone using the above.

The acrylic polyol (e13) is composed of an ethylenically unsaturated bond-containing monomer (e131) having a hydroxyl group, alone or as a mixture, and another ethylenically unsaturated bond-containing monomer (e132) copolymerizable therewith. It is obtained by copolymerizing alone or with a mixture.

Examples of the ethylenically unsaturated bond-containing monomer (e131) having a hydroxyl group include hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, and hydroxybutyl methacrylate. Etc. Preferred are hydroxyethyl acrylate and hydroxyethyl methacrylate.

Examples of other ethylenically unsaturated bond-containing monomer (e132) copolymerizable with the above monomer include methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, n-butyl acrylate, acrylic Acrylic acid ester such as isobutyl acid, acrylic acid-n-hexyl, cyclohexyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, benzyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, Isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, benzyl methacrylate, phenyl methacrylate Methacrylic acid esters, acrylic acid, methacrylic acid, maleic acid, itaconic acid and other unsaturated carboxylic acids, acrylamide, methacrylamide, N, N-methylenebisacrylamide, diacetone acrylamide, diacetone methacrylamide, maleic acid amide, maleimide Unsaturated amides such as glycidyl methacrylate, styrene, vinyl toluene, vinyl acetate, acrylonitrile, dibutyl fumarate and other vinyl monomers, vinyltrimethoxysilane, vinylmethyldimethoxysilane, γ- (meth) acryloxypropyl Examples thereof include vinyl monomers having hydrolyzable silyl groups such as trimethoxysilane.

Examples of the polyolefin polyol (e14) include polybutadiene having two or more hydroxyl groups, hydrogenated polybutadiene, polyisoprene, and hydrogenated polyisoprene.

The fluorine polyol (e15) is a polyol containing fluorine in the molecule, and examples thereof include copolymers such as fluoroolefin, cyclovinyl ether, hydroxyalkyl vinyl ether, and monocarboxylic acid vinyl ester.

As the polycarbonate polyols (e16), a low-molecular carbonate compound such as a dialkyl carbonate such as dimethyl carbonate, an alkylene carbonate such as ethylene carbonate, a diaryl carbonate such as diphenyl carbonate, and the low-molecular polyol used in the above-described polyester polyol, Examples thereof include those obtained by condensation polymerization.

The polyurethane polyol (e17) can be obtained by a conventional method, for example, by reacting a polyol and a polyisocyanate. Examples of the polyol not containing a carboxyl group include ethylene glycol and propylene glycol as low molecular weights, and examples of the high molecular weight include acrylic polyol, polyester polyol, and polyether polyol.

Polyamine (e2)
The polyamine (e2) has two or more amino groups, and examples thereof include a low molecular weight polyamine (e21), a high molecular weight polyamine (e22), and a polyamide polyamine (e23).

Examples of the low molecular weight polyamine (e21) include aromatic amines such as 4,4′-diphenylmethanediamine, araliphatic amines such as 1,3- or 1,4-xylylenediamine or mixtures thereof, for example, Alicyclic amines such as 3-aminomethyl-3,5,5-trimethylcyclohexylamine (common name: isophoronediamine), 1,3-bis (aminomethyl) cyclohexane, 1,4-cyclohexanediamine, such as ethylenediamine, Examples include aliphatic amines such as 1,3-propanediamine, 1,4-butanediamine, 1,6-hexamethylenediamine, hydrazine (including hydrates), diethylenetriamine, triethylenetetramine, and tetraethylenepentamine. It is done.

Examples of the high molecular weight polyamine (e22) include polyoxyalkylene diamine (weight average molecular weight 400 to 4000), polyoxyalkylene triamine (weight average molecular weight 400 to 5000), and the like.

Examples of the polyamide polyamine (e23) include compounds having both an amide bond and an amino group in the molecule, such as tomide series such as tomide 210, tomide 215-X, tomide 225-X, tomide 245, and tomide 275 (Fuji As a compound obtained by the reaction of an aliphatic amine and a dimer acid obtained by polymerizing an unsaturated natural fat fatty acid, for example, sunmide 305, sunmide 315, sunmide 328A, sunmide 330, sunmide 336, etc. No Sunamide series (made by Air Products Japan).

Alkanolamine (e3)
Examples of the alkanolamine (e3) include monoethanolamine, diethanolamine, aminoethylethanolamine, N- (2-hydroxypropyl) ethylenediamine, mono-, di- (n- or iso-) propanolamine, and ethylene glycol bis- Examples include propylamine, neopentanolamine, and methylethanolamine.

Of the compounds (e) having two or more active hydrogens in the molecule, an aliphatic amine polyol (e111) is preferable, and an alkylene oxide adduct of a polyalkylene polyamine is more preferable. It is an alkylene oxide adduct of ethylenediamine.
As a hydroxyl value of the alkylene oxide adduct of ethylenediamine, it is 100-1500 mgKOH / g normally, Preferably it is 200-1200 mgKOH / g.

Blocking agent (a)
The blocking agent (a) in the present invention is at least one selected from the group consisting of oxime (a1), compound (a2) having active methylene, pyrazole (a3) and secondary amine (a4).

  Examples of the oxime (a1) include acetooxime, methyl ethyl ketoxime, and methyl isobutyl ketoxime. Examples of the secondary amine (a4) include aliphatic amines (dimethylamine, diisopropylamine, di-n-propylamine, diisobutylamine, etc.), alicyclic amines (methylhexylamine, dicyclohexylamine, etc.), aromatic amines (aniline, Diphenylamine and the like). Examples of pyrazole (a3) include pyrazole, 3-methylpyrazole, 3,5-dimethylpyrazole and the like. Examples of the compound (a2) having active methylene include dimethyl malonate, diethyl malonate, diisopropyl malonate, acetylacetone, methyl acetoacetate, ethyl acetoacetate and the like. Of these, preferred are oxime (a1) and pyrazole (a3), and more preferred are methyl ethyl ketone oxime and 3,5-dimethylpyrazole. The blocking agent (a) may be used alone or in combination of two or more.

Block polyisocyanate compound (c)
The block polyisocyanate compound (c) has a structure in which the free isocyanate group of the polyisocyanate compound (b) is blocked with the blocking agent (a). (C) is usually obtained by reacting the polyisocyanate compound (b) with the blocking agent (a) or adding the blocking agent (a) at any stage of the urethane prepolymerization reaction. I can do it.

Examples of the polyisocyanate compound (b) include organic polyisocyanate (b1) and urethane prepolymer (b2). As the organic polyisocyanate (b1), all organic polyisocyanates generally used in the production of polyurethane resins can be used. For example, aromatic polyisocyanate (b11), aliphatic polyisocyanate (b12), alicyclic polyisocyanate (b13). ), Araliphatic polyisocyanate (b14) and modified products thereof (b15) (urethane group, carbodiimide group, allophanate group, urea group, burette group, isocyanurate group and oxazolidone group-containing modified product). An organic polyisocyanate component may be used individually by 1 type, or may use 2 or more types together.

  As the aromatic polyisocyanate (b11), an aromatic diisocyanate having 6 to 16 carbon atoms (excluding carbon in the NCO group; the following polyisocyanates are the same), an aromatic triisocyanate having 6 to 20 carbon atoms, and these Examples include crude isocyanates. Specific examples include 1,3- or 1,4-phenylene diisocyanate, 2,4- or 2,6-tolylene diisocyanate (TDI), crude TDI, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane. Examples include diisocyanate (MDI), polymethylene polyphenylene polyisocyanate (crude MDI), naphthylene-1,5-diisocyanate, and triphenylmethane-4,4 ′, 4 ″ -triisocyanate.

  Examples of the aliphatic polyisocyanate (b12) include aliphatic diisocyanates having 6 to 10 carbon atoms (such as 1,6-hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and lysine diisocyanate).

  Examples of the alicyclic polyisocyanate (b13) include alicyclic diisocyanates having 6 to 16 carbon atoms (such as isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, and norbornane diisocyanate).

Examples of the araliphatic isocyanate (b14) include araliphatic diisocyanates having 8 to 12 carbon atoms (such as xylylene diisocyanate and α, α, α ′, α′-tetramethylxylylene diisocyanate).
Specific examples of the modified polyisocyanate (b15) include carbodiimide-modified MDI.

Among the organic polyisocyanates (b1), aromatic polyisocyanates are preferable from the viewpoint of low-temperature curability of the plastisol composition.

The urethane prepolymer (b2) is a compound obtained by alternately addition-polymerizing a compound (p) having bifunctional or higher active hydrogen and an organic polyisocyanate (b1), and has an isocyanate group at the molecular terminal. The number average molecular weight Mn is 500 to 100,000, preferably 2000 to 30,000, and the isocyanate group content is 0.5 to 20% by weight, preferably 2.0 to 10% by weight.

In the blocking reaction of the polyisocyanate compound (b) and the blocking agent (a), all the isocyanate groups of the polyisocyanate compound (b) can be blocked, or a part of the isocyanate groups can be used depending on the purpose. Can also be left. When all the isocyanate groups are blocked, the (number of moles of polyisocyanate compound (b)) / (number of moles of blocking agent (a)) is preferably 1.0 to 3.0.

The blocking reaction can be generally carried out at 0 to 100 ° C., preferably 30 to 90 ° C. If it is 90 degrees C or less, a side reaction can be prevented, and on the other hand, if it is 30 degrees C or more, reaction rate will not become too low.

The blocking reaction of the polyisocyanate compound (b) and the blocking agent (a) can be performed regardless of the presence or absence of a solvent. When using a solvent, it is preferable to use a solvent inert to the isocyanate group.

In the blocking reaction, a reaction catalyst can be used. Specific examples of the reaction catalyst include organic metal salts such as tin, zinc and lead, metal alcoholates, and tertiary amines.

The blocked polyisocyanate compound (c) can also be obtained by adding and reacting the blocking agent (a) at any stage of the urethane prepolymerization reaction. In this case, the urethane prepolymer is obtained by reacting an excess organic polyisocyanate with the compound (p) having active hydrogen (the aforementioned polyol, polyamine, alkanolamine and a mixture of two or more thereof), Further, the blocked polyisocyanate compound (c) can be obtained by adding the blocking agent (a) and reacting the free isocyanate group with the blocking agent (a).

As a method of adding and reacting the blocking agent (a) at any stage of the urethane prepolymerization reaction, (1) a method of adding the blocking agent (a) in total together with the compound (p) having active hydrogen in advance , (2) A method of adding all of the blocking agent (a) at the initial stage of the urethane prepolymer formation reaction, (3) A part of the blocking agent (a) is added at the initial stage of the urethane prepolymer reaction or during the reaction, and the reaction A method of adding the remainder of the blocking agent (a) at the end of the process and (4) a method of adding the entire amount of the blocking agent (a) after producing a urethane prepolymer having an isocyanate group at the terminal are included. Among these, the method (4) is preferable from the viewpoint of the reproducibility of the reaction.

The isocyanate group content [NCO% (weight% in terms of solid content)] of the urethane prepolymer having an isocyanate group at the terminal in the method (4) is preferably 1 to 40%, more preferably 1.5 to 20%. It is. NCO% can be measured by a titration method or an infrared absorption spectrum method.

  In the case of the methods (1) to (3) in which the blocking agent (a) is added and reacted at the stage of the urethane prepolymerization reaction, the viewpoint of storage stability From the equivalent number of isocyanate groups of the polyisocyanate compound (b), it is preferable to use approximately the same equivalent number as that obtained by subtracting the active hydrogen-containing group equivalent number of the compound (p) having active hydrogen. In the case of the method of (4) in which the blocking agent (a) is added and reacted at the prepolymerization reaction stage, 1 to 2 equivalents from the viewpoint of storage stability with respect to the isocyanate group of the urethane prepolymer , Preferably 1.0 to 1.2 equivalents.

In the blocked polyisocyanate compound (c), the content of the isocyanate group (latent isocyanate group) blocked by the blocking agent (a) is preferably 1 to 10% by weight, and the organic polyisocyanate (b1) and active hydrogen are contained. The compounding ratio of the compound (p) it has can be arbitrarily changed within the range of the content.

The reaction temperature in the methods (1) to (4) in which the blocking agent (a) is added and reacted at the stage of the urethane prepolymerization reaction is usually 0 to 180 ° C., preferably from the viewpoint of suppressing side reactions. Is 20 to 150 ° C, more preferably 40 to 100 ° C.

In order to promote the reaction in the methods (1) to (4) in which the blocking agent (a) is added and reacted at the stage of the urethane prepolymerization reaction, a known urethane catalyst can be used. . Examples of the urethane catalyst include metal catalysts such as tin, zinc, lead, bismuth and titanium, and tertiary amines.

The reaction in the methods (1) to (4) in which the blocking agent (a) is added and reacted at the stage of the urethane prepolymerization reaction can be performed regardless of the presence or absence of a solvent. When using a solvent, it is preferable to use a solvent inert to the isocyanate group.

Block polyisocyanate dissociation catalyst (f)
Examples of the block polyisocyanate dissociation catalyst (f) include a metal catalyst (m) and an amine catalyst (n). A metal catalyst (m) and an amine catalyst (n) may be used independently and may use 2 or more types together.

Examples of the metal catalyst (m) include an organometallic compound (m1) having a bond between the metal (m0) and carbon, a metal complex (m3) having a coordination bond with the metal (m0), and the metal (m0). 1 type (s) or 2 or more types selected from the group consisting of the carboxylate (m3).

Examples of the organometallic compound (m1) include dibutyltin dilaurate, dibutyltin di-2-ethylhexanate, dioctyltin dilaurate, dibutyltin diacetate, dimethyltin dimaleate, dibutyltin dioxide, and dioctyltin oxide. Examples thereof include organic titanium such as tetra-n-butyl acid and tetraisopropyl titanate, organic bismuth, organic lead, and organic nickel.

Examples of the metal complex (m2) include metal (M) acetylacetonate salts such as tin acetylacetonate, bismuth acetylacetonate, titanium acetylacetonate, lead acetylacetonate, zirconium acetylacetonate, iron, and the like. Examples thereof include acetylacetonate, aluminum acetylacetonate, zinc acetylacetonate, manganese acetylacetonate, and cobalt acetylacetonate.

Examples of the carboxylic acid metal salt (m3) include tin carboxylate (tin octylate, tin acetate, tin laurate, tin oleate, etc.), bismuth carboxylate (bismuth octylate, bismuth naphthenate, etc.), lead carboxylate Series (lead oleate, lead 2-ethylhexanoate, lead naphthenate, lead octenoate, etc.), nickel carboxylate (nickel octylate, nickel naphthenate, etc.), titanium carboxylate (titanium terephthalate, etc.) Can be mentioned.

Among the metal catalysts (m), the metal (m0) is preferably one or more metals selected from the group consisting of Sn, Bi, Ti, Pb, Zr, Fe, Al, Zn, and Mn ( m0), an organometallic compound (m11), a metal complex (m12) having a coordinate bond with the metal (m0), and a carboxylate (m13) of the metal (m0), more preferably dibutyl Tin dilaurate, tin octylate, bismuth octylate, bismuth naphthenate, tin acetylacetonate, bismuth acetylacetonate, titanium acetylacetonate.

Examples of the amine catalyst (n) include primary to tertiary amines (n1) and quaternary ammonium salts (n2). An amine catalyst may be used independently and may use 2 or more types together.

As primary to tertiary amines (n1), bis (dimethylaminoethyl) ether, pentamethyldiethylenetriamine, pentamethyldipropylenetriamine, N-methyl- (dimethylaminopropyl) aminoethanolamine, dimorpholinodiethyl ether, dimethylaminoethanol , Dimethylaminoethoxyethanol, trimethylaminoethylethanolamine, dimethylethanolamine, tetramethylethylenediamine, tetramethylpropylenediamine, tetramethylhexamethylenediamine, dimethylcyclohexylamine, methyldicyclohexylamine, triethylenediamine, tris (3-dimethylaminopropyl) Amines, tris (3-dimethylaminopropyl) hexahydro-s-triazine, tris (dimethylamino) Methyl) phenol, 1-methylimidazole, 1,2-dimethylimidazole, 1-isobutyl-2-methylimidazole, methylmorpholine, ethylmorpholine, dimethylaminoethylmorpholine, 1,8-diazabicyclo [5,4,0] -undecene -7 (DBU), weak acid salt of 1,8-diazabicyclo [5,4,0] -undecene-7 (phenol salt, 2-ethylhexanoate, formate, etc.), 1,5-diazabicyclo [4,3 , 0] -Nonene-5, 1,5-diazabicyclo [4,3,0] -nonene-5 weak acid salt (phenol salt, 2-ethylhexanoate, formate, etc.), 1,2-dimethyltetrahydropyrimidine , 2-dimethyltetrahydropyrimidine weak acid salt (phenol salt, 2-ethylhexanoate, formate, etc.), tetramethylgua Nigin and the like can be mentioned.

Examples of the quaternary ammonium salt (n2) include the following weak salts of quaternary ammonium (phenol salt, 2-ethylhexanoate, formate, etc.). As quaternary ammonium, tetramethylammonium, methyltriethylammonium, ethyltrimethylammonium, propyltrimethylammonium, butyltrimethylammonium, pentyltrimethylammonium, hexyltrimethylammonium, heptyltrimethylammonium, octyltrimethylammonium, nonyltrimethylammonium, decyltrimethylammonium, Undecyltrimethylammonium, dodecyltrimethylammonium, tridecyltrimethylammonium, tetradecyltrimethylammonium, heptadecyltrimethylammonium, hexadecyltrimethylammonium, heptadecyltrimethylammonium, octadecyltrimethylammonium, triethylmethylammoni , Tetraethylammonium, tetrapropylammonium, tetrabutylammonium, 1-methyl-1-azania-4-azabicyclo [2,2,2] octanium, 1,1-dimethyl-4-methylpiperidinium, 1-methylmol As folinium, 1-methylpiperidinium, and trialkylhydroxypropylammonium, (2-hydroxypropyl) trimethylammonium, (2-hydroxypropyl) triethylammonium, (2-hydroxypropyl) tripropylammonium, (2-hydroxypropyl) ) Tributylammonium, hydroxyethyltrimethylammonium, trimethylaminoethoxyethanol and the like.

Of the amine catalysts (n), preferred are amine catalysts containing a strong base having an acid dissociation constant (pKa) of 11 or more, and more preferred are 1,8-diazabicyclo [5,4,0]. -Undecene-7 (DBU), 1,8-diazabicyclo [5,4,0] -undecene-7 weak acid salt (phenol salt, 2-ethylhexanoate, formate, etc.), 1,5-diazabicyclo [4 , 3,0] -Nonene-5, 1,5-diazabicyclo [4,3,0] -nonene-5 weak acid salt (phenol salt, 2-ethylhexanoate, formate, etc.), tetramethylammonium weak acid Salt (phenol salt, 2-ethylhexanoate, formate, etc.), methyltriethylammonium weak acid salt (phenol salt, 2-ethylhexanoate, formate, etc.), tetraethylammonium weak acid salt (pheno Le salt, 2-ethyl hexanoate, formate salt, etc.), a (2-hydroxypropyl) weak acid salt of trimethylammonium (phenol salt, 2-ethyl hexanoate, formate salt, etc.).

Strong acid (g) having an acid dissociation constant (pKa) of 2 or less
Examples of the strong acid (g) having an acid dissociation constant (pKa) of 2 or less include the following organic acids (g1) and inorganic acids (g2). An organic acid and an inorganic acid may be used independently and may use 2 or more types together.

Organic acids (g1) include carboxylic acids (halogen-substituted aliphatic carboxylic acids (difluoroacetic acid, trifluoroacetic acid, dichloroacetic acid, trichloroacetic acid, dibromoacetic acid, tribromoacetic acid, 2,2-dibromopropionic acid, etc.), nitro-substituted fatty acids Aromatic carboxylic acids (nitroacetic acid, etc.), ammonium-substituted aliphatic carboxylic acids (trimethylammonium acetic acid, etc.), saturated aliphatic dicarboxylic acids (succinic acid, ethylbutylmalonic acid, etc.), unsaturated aliphatic dicarboxylic acids (maleic acid, acetylenedicarboxylic acid) , Chloromaleic acid, bromomaleic acid, chlorofumaric acid, bromofumaric acid, etc.)}, organic phosphonic acids (such as 2-aminoethylphosphonic acid), sulfonic acids (methanesulfonic acid, ethanesulfonic acid, trifluoromethanesulfonic acid, vinylsulfone) Acid, cyclamy Acid, benzenesulfonic acid, p- toluenesulfonic acid, cumene sulfonic acid, naphthalene sulfonic acid, etc.) and the like.
Of these, methanesulfonic acid is preferred.
The adhesion-imparting agent (J) has a block polyisocyanate compound (c), a compound having two or more active hydrogens in the molecule (e), a block polyisocyanate dissociation catalyst (f) and an acid dissociation constant (pKa) of 2 or less. The weight ratio of (c), (e), (f) and (g) is preferably 80.0 / 10.0 / 5.0 / 5.0 to 99.0. /0.998/0.001/0.001, more preferably 90.0 / 8.0 / 1.0 / 1.0 to 96.0 / 3.98 / 0.01 / 0.01.

The adhesiveness imparting agent (J) is composed of a main agent (D) and a curing agent (H).
The main agent (D) can contain a plasticizer (L1) for the purpose of adjusting its viscosity. As the plasticizer (L1), a plasticizer (L) described later can be used. Content of a plasticizer (L1) becomes like this. Preferably it is 0 to 80 weight% with respect to the weight of a main ingredient (D), More preferably, it is 0 to 50 weight%.
Examples of the main agent (D) include block polyisocyanate compounds, and examples of the curing agent (H) include compounds having active hydrogen. The weight ratio [main agent (D) / curing agent (H)] is preferably 20/80 to 95/5, more preferably 25/75 to 90/10, from the viewpoint of curability.

Thermoplastic resin (K)
Examples of the thermoplastic resin (K) include an acrylic polymer (K1) and a vinyl chloride polymer (K2). A thermoplastic resin may be used individually by 1 type, or may use 2 or more types together.

  As an acrylic polymer (K1), what is normally used for plastisol can be used, For example, what is described in Unexamined-Japanese-Patent No. 2007-39659 is mentioned. Among acrylic polymers, preferred from the viewpoint of chipping resistance are homopolymers of methyl (meth) acrylate and copolymers of methyl (meth) acrylate and other monomers, and more preferred are (meth). These are a homopolymer of methyl acrylate and a copolymer of methyl (meth) acrylate and butyl (meth) acrylate. An acrylic polymer may be used individually by 1 type, or may use 2 or more types together.

  The Mn of the acrylic polymer (K1) is not particularly limited, but is preferably 100,000 to 5,000,000, more preferably 300,000 to 3,000,000 from the viewpoint of chipping resistance.

  Mn of the acrylic polymer (K1) is measured by gel permeation chromatography using tetrahydrofuran as a solvent and polystyrene as a molecular weight standard substance.

  The form of the acrylic polymer (K1) is usually a fine particle powder, and the volume average particle size of the fine particles is preferably 0.1 to 50 μm, more preferably 0.2 to 10 μm. The volume average particle diameter of the fine particles can be measured by, for example, a dynamic light scattering method using a laser diffraction / scattering particle size distribution measuring apparatus.

  As the vinyl chloride polymer (K2), those commonly used for plastisols can be used. For example, vinyl chloride homopolymers and other vinyl monomers that can be copolymerized with vinyl chloride monomers (vinyl acetate, maleic anhydride, And maleic acid esters and vinyl ethers).

  The degree of polymerization of the vinyl chloride polymer (K2) is usually 1000 to 1700. Commercially available products of the vinyl chloride polymer (K2) include “Kane Vinyl PSL-10”, “Kane Vinyl PSH-10” and “Kane Vinyl PCH-12” [manufactured by Kaneka Corporation], “Zeon 121” and “Zeon 135J”. ] [Manufactured by Nippon Zeon Co., Ltd.], and “DENKA VINYL PA-100” and “DENKA VINYL ME-180” [manufactured by Electrochemical Factory Co., Ltd.]. These may be used in combination of two or more.

  As the plasticizer (L), aromatic carboxylic acid ester [diethyl phthalate (DEP), dibutyl phthalate (DBP), di-2-ethylhexyl phthalate (DOP), dilauryl phthalate, distearyl phthalate, diisononyl phthalate (DINP), etc. Phthalic acid esters, etc.], aliphatic carboxylic acid esters [methylacetylricinoleate, di-2-ethylhexyl adipate (DOA), di-2-ethylhexyl sebacate (DOS), adipic acid-propylene glycol polyester and 2,2, 4-trimethyl-1,3-pentanediol diisobutyrate and the like], phosphate esters [triphenyl phosphate and tricresyl phosphate and the like], and mixtures of two or more thereof. Of these, aromatic carboxylic acid esters are preferred from the viewpoint of compatibility with the adhesion-imparting agent (J).

  The content of each component based on the total weight of the adhesion-imparting agent (J), the thermoplastic resin (K) and the plasticizer (L) in the plastisol composition of the present invention is not particularly limited. It is as follows. The content of the adhesion-imparting agent (J) is preferably 1 to 40% by weight, more preferably 2 to 30% by weight, from the viewpoint of the adhesion of the plastisol to the metal coating surface. The content of the thermoplastic resin (K) is preferably 10 to 80% by weight, more preferably 25 to 60% by weight, from the viewpoint of the viscosity of the plastisol. The content of the plasticizer (L) is preferably 5 to 50% by weight, more preferably 10 to 45% by weight, from the viewpoint of chipping resistance. Here, the content of the plasticizer (L) does not include the plasticizer (L1) that may be contained in the main agent.

  The chipping-resistant coating material of the present invention contains a plastisol composition, but other additives (fillers, foaming agents, colorants, stabilizers, diluents, etc.) as long as they do not impair the effects of the present invention if necessary. Containing. The total amount of other additives is usually 80% by weight or less, preferably 1 to 60% by weight, based on the total weight of the chipping-resistant paint.

  As fillers, inorganic fillers (calcium carbonate, talc, clay, Tey alga, silicate, silicate, kaolin, asbestos, mica, glass fiber, glass balloon, carbon fiber, metal fiber, ceramic whisker and titanium whisker) And organic fillers [cellulose powder, powder rubber, organic cross-linked fine particles (epoxy, urethane, etc.), urea, etc.]. The amount of the filler used is usually 80% by weight or less, preferably 10 to 60% by weight, from the viewpoint of the viscosity of the plastisol, based on the total amount of the chipping-resistant paint.

Foaming agents include azo foaming agents (azodicarbonamide and azobisisobutyronitrile, etc.), nitroso foaming agents (dinitrosopentamethylenetetramine, etc.) and hydrazide foaming agents [toluenesulfonyl hydrazide and oxybis (benzenesulfonyl hydrazide). And the like]. The amount of the foaming agent used is usually 5% or less, preferably 0.1 to 2%, based on the total weight of the chipping-resistant paint.

  Examples of the colorant include inorganic pigments, organic pigments, and dyes. Examples of inorganic pigments include white pigments, cobalt compounds, iron compounds (such as iron oxide and bitumen), chromium compounds, and sulfides. Examples of organic pigments include azo pigments and polycyclic pigments. As dyes, azo compounds, anthraquinone compounds, indigoid compounds, sulfur compounds, triphenylmethane compounds, pyrazolone compounds, stilbene compounds, diphenylmethane compounds, xanthene compounds, alizarin compounds, acridine compounds, Examples thereof include quinoneimine compounds, thiazole compounds, methine compounds, nitro compounds, nitroso compounds, and aniline compounds. The amount of the colorant used is usually 5% by weight or less, preferably 0.1 to 2% by weight, based on the total weight of the chipping-resistant paint.

  Stabilizers include metal soaps (such as calcium stearyl and aluminum stearyl), inorganic acid salts (such as dibasic phosphites and dibasic sulfates), and organometallic compounds (dibutyltin dilaurate and dibutyltin). Maleate) and the like. The amount of the stabilizer used is usually 10% by weight or less, preferably 0.2 to 5% by weight, based on the total weight of the chipping-resistant paint.

As the diluent, solvents such as xylene and mineral terpenes can be used. Based on the total weight of the chipping resistant paint, it is usually 20% or less, preferably 5 to 15%.

  By applying the chipping-resistant coating material of the present invention to various metal (especially steel) surfaces and heat-treating it, a cured product having excellent coating appearance, chipping resistance and adhesion to the metal-coated surface can be obtained. The plastisol composition of the present invention can be applied to various undercoat coated surfaces, but can be advantageously applied particularly to cationic electrodeposition coated surfaces from the viewpoint of adhesion of the chipping-resistant paint.

The application amount of the chipping resistant coating is preferably 500 to 3,000 g / m ² from the viewpoint of chipping resistance, and the coating film thickness is preferably 0.5 to 3 mm from the viewpoint of chipping resistance. Examples of the application method include brush coating, spatula coating, roller coating, and airless spray coating. Airless spray coating is preferred from the viewpoint of coating efficiency and the application of a high-viscosity anti-chipping coating. In addition, although heat treatment is performed after coating, the heat treatment temperature is preferably 90 to 180 ° C., more preferably 90 to 140 ° C. from the viewpoint of adhesion and curability of the chipping-resistant paint, and the heat treatment time is preferably from the same viewpoint. 10 to 50 minutes, more preferably 15 to 40 minutes.

  The chipping-preventing steel sheet obtained by applying the chipping-resistant paint of the present invention to at least a part of the surface of the steel sheet and curing the chipping-resistant paint by heat treatment is excellent in all of the coating appearance, chipping resistance, and adhesion to the metal coated surface. Therefore, it can be used mainly as a steel plate in a portion where chipping is likely to occur, such as a lower surface of a vehicle body, a side sill, and a tire house, and rusting and corrosion due to chipping can be prevented.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not limited to this. In the following description, “parts” indicates parts by weight.

<Production Examples 1 to 3> Production of main agents (D-1) to (D-3) In a reaction vessel equipped with a stirrer and a thermometer, compounds (p) having organic hydrogen in the number of parts shown in Table 1, organic poly Isocyanate (b1) and a plasticizer (L1-1) “DINP” [diisononyl phthalate manufactured by J-PLUS Co., Ltd.] were charged, reacted at 80 ° C. for 5 hours in a dry nitrogen atmosphere, and cooled. Thereafter, the blocking agent (a) shown in Table 1 was charged at 50 ° C., and the terminal blocking reaction was carried out at the same temperature for 2 hours. The blocked polyisocyanate compounds (c-1) to (c-3) and the plasticizer ( Main agents (D-1) to (D-3) comprising L1-1) were obtained.

<Manufacture example 4> Manufacture of main ingredient (D-4) The compound (p) and organic polyisocyanate (b1-2) which have the number of parts of active hydrogen shown in Table 1 in the reaction container provided with the stirrer and the thermometer. The mixture was allowed to react at 80 ° C. for 5 hours under a dry nitrogen atmosphere and cooled. Thereafter, the blocking agent (a-1) shown in Table 1 was charged at 50 ° C., and the terminal blocking reaction was carried out at the same temperature for 2 hours to form the main agent (D-4) comprising the blocked polyisocyanate compound (c-4). Got.

<Production Example 5> Production of main agent (D-5) In a reaction vessel equipped with a stirrer and a thermometer, the parts of organic polyisocyanate, blocking agent (a-1) and plasticizer (L1-1) shown in Table 1 were prepared. ) And a terminal blocking reaction was carried out at 80 ° C. for 2 hours to obtain a main agent (D-5) comprising a blocked polyisocyanate compound (c-5) and a plasticizer (L1-1).
The compositions of the main agents (D-1) to (D-5) are shown in Table 1.

<Examples 1 to 27 and Comparative Examples 1 to 20>
The thermoplastic resin “Zeon F-320” [manufactured by Nippon Zeon Co., Ltd.] is used for a mixture of 100 parts of the main agent (D) shown in Table 2 and a compound (e) having two or more active hydrogens in the molecule. Methyl methacrylate polymer (Mn = 3 million, powder with a volume average particle size of 1 μm)] 150 parts, filler “Shiraka Hana CC-R” [Shiraishi Kogyo Co., Ltd. surface-treated ultrafine calcium carbonate (volume average particle size) 0.08 μm)] 200 parts, the number of blocked isocyanate dissociation catalysts (f) shown in Table 2, strong acid (g) having an acid dissociation constant (pKa) of 2 or less, plasticizer (L-1) “DINP” [(stock) ) Diplusonyl phthalate made by Jplus] 200 parts were added and uniformly kneaded with a disper to produce chipping resistant paints (M-1) to (M-27) of Examples 1 to 27 shown in Tables 2-6. . Similarly, chipping resistant paints (M′-1) to (M′-20) of Comparative Examples 1 to 20 were obtained.
Tables 2 to 6 show the results of measuring or evaluating the initial viscosity, the viscosity after storage, the storage stability, the low temperature curability, the adhesion, and the chipping resistance of each chipping-resistant paint by the following methods.

[Test method for performance evaluation of plastisol composition]
(1) Initial viscosity The viscosity at 25 ° C. immediately after the production of the plastisol composition is measured using a BH viscometer [manufactured by Tokyo Keiki Co., Ltd.].
(2) Viscosity after storage Immediately after producing the chipping-resistant coating material, 90 g of the chipping-resistant coating material is put into a cylindrical container with a glass stopper having an inner diameter of about 4 cm and a height of about 8 cm. Measure as in 1).
(3) Storage stability The viscosity increase rate (%) after storage with respect to the initial viscosity at the time of preparation of a chipping-resistant paint is calculated from the following formula. The smaller the value, the better the storage stability.
Viscosity increase rate after storage (%) = (viscosity after storage−initial viscosity) / initial viscosity × 100

(4) Low-temperature curing epoxy resin-based cationic electrodeposition coating [trade name: Konak / No. 3500, manufactured by Nippon Oil & Fats Co., Ltd.], a frame is attached to the coated surface of the coated steel plate (hereinafter abbreviated as electrodeposition coated steel plate) so that the content is 50 × 20 × 1 mm. The chipping paint was applied with a spatula so that the film thickness became 1 mm, and after heat treatment at 100 to 120 ° C. for 20 minutes, the degree of cure of the coating film was judged by the following criteria by finger touch.
+2: No tack and good curability +1: Slightly tacky but curable enough for practical use −1: There is tack and insufficient curability −2: No cure at all

(5) Adhesion Spatally apply a chipping-resistant paint to the end of the coated surface of the electrodeposited steel sheet of length 100 mm x width 25 mm x thickness 1 mm (area approx. 2 x 2 cm ² ). Then, the end of another electrodeposited steel sheet was crimped. In this state, after baking heat treatment at 110 ° C. for 20 minutes, the ends of the two electrodeposition coated steel sheets were pulled at a tensile speed of 50 mm / min. Evaluation was based on the criteria.
+2: Cohesive failure +1: Coexistence failure and interface peeling coexist 0: Interface peeling

(6) Chipping resistance test: A chipping-resistant paint was applied to a coated surface of an electrodeposited steel sheet of length 100 mm x width 100 mm x thickness 0.8 mm and baked at 110 ° C for 20 minutes. A piece is attached to the nut dropping device, and a 3-M-4 brass hex nut specified in JIS B 1181 is passed through a cylinder having a diameter of 20 mm from a height of 2 m and has an angle of 45 ° with respect to the nut dropping direction. The test piece was dropped on a test piece, and the nut dropping operation was repeated until the scratch on the coating film reached the metal surface. The larger this value, the better the chipping resistance.

  The plastisol composition and the chipping-resistant paint of the present invention are particularly useful for the production of an automobile outer plate because of excellent storage stability, low-temperature curability, adhesion to a metal-coated surface, and chipping resistance.

Claims (10)

Block polyisocyanate compound (c) which is a reaction product of blocking agent (a) and polyisocyanate compound (b), compound (e) having two or more active hydrogens in the molecule, block polyisocyanate dissociation catalyst ( f) and an plastisol composition containing an adhesion-imparting agent (J) containing a strong acid (g) having an acid dissociation constant (pKa) of 2 or less, a thermoplastic resin (K) and a plasticizer (L). Adhesiveness imparting agent (J) contains main component (D) containing blocked polyisocyanate compound (c) which is a reaction product of blocking agent (a) and polyisocyanate compound (b), and two in the molecule The compound (e) having the above active hydrogen, the block polyisocyanate dissociation catalyst (f) and the curing agent (H) containing a strong acid (g) having an acid dissociation constant (pKa) of 2 or less. The plastisol composition described.   The plastisol composition according to claim 1 or 2, wherein the content of the strong acid (g) having an acid dissociation constant (pKa) of 2 or less relative to the number of moles of the block polyisocyanate dissociation catalyst (f) is 1 to 300 mol%. .   The plastisol composition according to any one of claims 1 to 3, wherein the strong acid (g) is a sulfonic acid (g1).   The plastisol composition according to any one of claims 1 to 4, wherein the compound (e) having two or more active hydrogens in the molecule is a polyol (e1) having an amino group.   The block polyisocyanate dissociation catalyst (f) is a bond between one or more metals (m0) and carbon selected from the group consisting of Sn, Bi, Ti, Pb, Zr, Fe, Al, Zn, and Mn. Organometallic compound (m1), metal complex (m2) having a coordinate bond with the metal (m0), carboxylate (m3) of the metal (m0), acid dissociation constant (pKa) of 11 or more The plastisol composition according to any one of claims 1 to 5, which is one or more selected from the group consisting of a basic amine (n1) and a quaternary ammonium salt (n2).   The plastisol composition according to any one of claims 1 to 6, wherein the blocking agent (a) is at least one selected from the group consisting of an oxime, a compound having active methylene, pyrazole and a secondary amine. The plastisol composition according to any one of claims 1 to 7, wherein the polyisocyanate compound (b) is a urethane prepolymer having an aromatic polyisocyanate and / or an aromatic polyisocyanate as a structural unit. A chipping resistant paint containing the plastisol composition according to any one of claims 1 to 8.   A chipping-preventing steel plate having a cured product of the plastisol composition according to any one of claims 1 to 8 on at least a part of a steel plate surface.