JPH03203974A - Coating composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition, composed of a chief component composed of a blocked substance of a specific urethane polymer with a lactam compound, etc., and a specified oxidizing agent, capable of closely adhering to ground films and curing at low temperatures in a short time and excellent in coating properties, chipping resistance and storage stability. CONSTITUTION:The objective composition composed of (A) a chief component composed of a blocked substance of a urethane prepolymer, having isocyanate groups and prepared from an organic polyisocyanate containing alpha,alpha,alpha',alpha'- tetramethylxylylene diisocyanate and polyols with a lactam compound and/or a blocked substance with an oxime compound and (B) a curing agent selected from the group of polyoxyalkylene polyamines, oxyalkylene ethers of (poly) alkylene polyamines and ketimines of the polyoxyalkylene polyamines, polyamide compounds, ketimines of the polyamide compounds, ketimines of the (poly) alkylene polyamines and epoxy-modified substances thereof.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a coating composition.

[Prior Art] Conventionally, one-component urethane paints that can be used as paint compositions, especially chipping-resistant paints, are made from blocked urethane prepolymers using organic polyisocyanates such as tolylene diisocyanate and polyoxyalkylene polyamines. (For example, JP-A-59-
2280E12).

[Problems to be Solved by the Invention] [11 However, this composition is
There are problems in that sufficient adhesion (hardenability) cannot be obtained by heat treatment at 20° C. for 15 minutes, and chipping resistance is also insufficient.

[Means for Solving the Problems] The present inventors have developed a product that has sufficient adhesion (curability) by heat treatment at a relatively low temperature and in a short time, and has excellent paintability, chipping resistance, and storage stability. As a result of extensive research into paint compositions, the present invention was achieved.

That is, the present invention provides (1) a blocked product (a1 ) and/or a main agent consisting of a blocked product (a2) with an oxime compound; (
2) Polyoxyalkylene polyamine [1], oxyalkylene ether of (poly)alkylene polyamine [
2], Ketimine of polyoxyalkylene polyamine [3
], a polyamide compound [4], a polyamide compound ketimine [5], a (poly)alkylene polyamine ketimine 01, and an epoxy modified product thereof [7]. It is a paint composition.

The block material of (1) used in the present invention is paper
α, α, α″, α″-Tetramethylxylylene diisocyanate, [hereinafter also referred to as Tl1XD I]. ] An average functional group number of 2.01 consisting of an organic polyisocyanate containing a polymer polyol and, if necessary, a low molecular polyol.
Examples include blocked products of urethane prepolymers having isocyanate groups at the terminals of the above polyols.

In the organic polyisocyanate containing TIIDI, T
IIXDI includes 0-9■-2p and mixtures thereof. Preferably it is -TIXDI.

Examples of polyisocyanates other than TMIDI include aliphatic polyisocyanates [hexamethylene diisocyanate (HDυ, hexamethylene isocyanurate,
lysine diisocyanate], alicyclic polyisocyanate [hydrogenated diphenylmethane diisocyanate (water +
1ffiMD1), isophorone diisocyanate (
IPDI), isophorone isocyanurate, cyclohexane diisocyanate (CIIDI), hydrogenated tolylene diisocyanate, hydrogenated xylylene diisocyanate, etc.], aromatic polyisocyanate [tolylene diisocyanate (TDI) 2) rylene isocyanurate, diphenylmethane diisocyanate CMDI )
, naphthylene diisocyanate, xylylene diisocyanate, etc.] and mixtures of two or more thereof.

Among these, aromatic polyisocyanates are preferred, and tolylene diisocyanate is particularly preferred.

The amount of TMID I in the organic polyisocyanate is usually 5
It is 0% by weight or more, preferably 60% or more.

As a polymer polyol, the molecular weight per hydroxyl group is usually 5.
00 to 3000 polymer polyols are mentioned.

Examples of the polymer polyols include polyether polyols, polyester polyols, polymer polyols, polycarbonate polyols, and mixtures of two or more thereof.

Examples of polyether polyols include polytetramethylene glycol (PTNG) that can be obtained by ring-opening polymerization of tetrahydrofuran. Polytetramethylene glycol is described in JP-A-58-11518. Furthermore, alkylene oxide adducts of low-molecular polyols can also be used.

Examples of low-molecular polyols include diols having a molecular weight per hydroxyl group of usually 30 to 5,001, preferably 30 to 400, such as ethylene glycol, propylene glycol,
l,4-butanediol, 1. B-hexanediol and 3-methyl-1,5-bentanediol; molecular weight per hydroxyl group is usually 3O-HO, preferably 40-50
0 low molecular weight triols such as glycerin, trimethylolpropane, and mixtures of two or more thereof. Examples of the alkylene oxide include ethylene oxide, propylene oxide, l, 2-. 1.3
- or 2,3-butylene oxide, tetrahydrofuran, styrene oxide, epichlorohydrin, and mixtures of two or more of these.

Examples of the polyester polyol include polyester polyols obtained by polycondensing dicarboxylic acids, their esters or halides, and low-molecular polyols. Examples of dicarboxylic acids include aliphatic dicarboxylic acids (adipic acid, sepathic acid, maleic acid, dimer acid, etc.), aromatic dicarboxylic acids (terephthalic acid, isophthalic acid, etc.), and their anhydrides. Among the dicarboxylic acids, preferred are aliphatic dicarboxylic acids, and particularly preferred is adipic acid. Examples of the low-molecular polyol include those described in the section on polyether polyols, and preferred are ethylene glycol and 1,4-butanediol. Also usable are polylactone polyols such as polycaprolactone diol (PCL) obtained by ring-opening polymerization of lactones (epsilon-caprolactone, etc.) in the presence of low-molecular polyols (ethylene glycol, etc.).

As the polymer polyol, those described in JP-A-55-118948 can be used.

Examples of polycarbonate polyols include those obtained from the above-mentioned low-molecular-weight polyols (di- or trihydric alcohols) and carbonic acid diesters (dimethyl carbonate, diethyl carbonate, etc.).

Among the polymeric polyols, preferred are polytetramethylene glycol and polyester polyol (especially polyethylene adipate diol and polycaprolactone polyol).

Examples of low-molecular polyols include those described in the section on polyether polyols, low-molar adducts of alkylene oxides (low-molecular-weight ones), and mixtures of two or more of these. Preferred among these are ethylene glycol and trimethylolpropane.

Average number of functional groups is 2.0! Examples of the above polyols are (
b) Trifunctional polymer polyol with a molecular weight per hydroxyl group of 500 to 3000 and a molecular weight per hydroxyl group of 40 to 50
A polyol consisting of a low molecular weight triol of 0 and (b)
Examples thereof include trifunctional polymeric polyols having a molecular weight per hydroxyl group of 500 to 2,500 and polyols consisting of low molecular weight diols having a molecular weight per hydroxyl group of 30 to 400.

Urethane prepolymer (a) having isocyanate groups
In the organic polyisocyanate and polyols, N
The eo10H equivalent ratio is usually 1.3 to 3.01, preferably 1.5 to 2.2.

In carrying out the prepolymer production reaction, known polymerization catalysts such as dibutyltin dilaurate, stannous octoate, stannous octoate, organometallic compounds, triethylenediamine, triethylamine, 1,8-diazabicyclo[ It is also possible to use tertiary amine compounds such as 5,4,0]undecene-7.

The reaction is usually carried out in the presence of a solvent. In general, all solvents used for this purpose are effective; examples include aromatic hydrocarbons (toluene, xylene, trimethylbenzenato), esters (ethyl acetate, butyl acetate, etc.), ethers (dioxane, etc.), and ethers (dioxane, etc.). , cellosolve acetate, etc.), ketone solvents (acetone, methyl ethyl ketone, etc.), and mixed solvents of two or more of these solvents.

The reaction temperature is usually 40-140°C, preferably 60-12°C.
It is 0°C. The reaction time is usually 3 to 10 hours, preferably 5 to 8 hours.

The molecular weight of the obtained urethane prepolymer (a) that grows isocyanate groups is usually 500 to 100,001, preferably 700 to 500. When the molecular weight is less than 500, the resin becomes hard and brittle, which has an unfavorable effect on chipping resistance, and when it exceeds 10,000, it is difficult to obtain good adhesion. In addition, 100% of this prepolymer
is usually 1 to 20%, preferably 2 to 15%.

Oxime compounds used to obtain blocked urethane prepolymers include acetoxime, ketoxime such as methyl ethyl ketoxime (NHK oxime), methyl isobutyl ketoxime (formerly BK oxime, etc.). Preferred is MEK oxime.

As a lactam compound, ε-caprolactam.

Examples include δ-parerolactam and γ-butyrolactam. Preferred is ε-caprolactam.

Along with these, other blocking agents such as active methylene compounds [malonate diesters (diethyl malonate, etc.)
, acetylacetone, acetoacetate (ethyl acetoacetate, etc.); Phenols (phenol, enteric-cresol, etc.); Alcohols (methanol, ethanol, n-butanol, etc.); Hydroxyl group-containing ethers (methyl cellosolve, butyl cellosolve, etc.); Containing esters (ethyl lactate, amyl lactate, etc.); Mercaptans (butyl mercaptan, hexyl mercaptan, etc.); Acid amides (acetanilide, acrylamide, dimer acid amide, etc.); Imidazole (imidazole, 2-ethylimidazole, etc.): Acids Imides (succinimide, phthalimide, etc.) can also be used in combination.

Among these, blocking agents suitable for relatively low-temperature baking are those whose dissociation humidity for regenerating isocyanate groups is generally within the range of 50 to 100°C, although this varies depending on the type of isocyanate.

The blocking agent can be added at any stage of the above reaction to cause the reaction to yield blocked urethane prepolymers (a 1) and/or (a2). Possible methods of addition include adding at the end of a predetermined polymerization, adding at the beginning of the polymerization, or adding a portion at the beginning of the polymerization and adding the remainder at the end of the polymerization. Preferably,
This is a method in which it is added at the end of polymerization.

The amount added is 11GO when added at the end of polymerization.
The amount is usually 1 equivalent or more, less than 2 equivalents, preferably 1.05 to 1.5 equivalents, based on the free isocyanate groups of the prepolymer. When adding a blocking agent during the process, it is preferable to use an amount approximately equivalent to the equivalent of lICO of the raw material polyisocyanate minus the equivalent of the polyol.

The reaction temperature when adding a blocking agent is usually 50°C.
~150°C. It is also possible to accelerate the reaction by adding a known catalyst for urethane polymerization.

Among the main ingredients, (a1) and/or (a2) and (b
The combination of 2) and/or (b2) is preferred from the viewpoint of widening the range of balance between low temperature curability and storage stability. That is, (b1) and/or (be) can be contained in an amount of 0% or more and 80% or less based on the total weight of the base ingredient.
) are each effective in promoting curability. However, if the total weight (tz) of the base resin exceeds 81%, sufficient low-temperature curability cannot be obtained. Furthermore, if (be) exceeds 81%, sufficient storage stability cannot be obtained.

The polyoxyalkylene polyamine (2) in the present invention includes, for example, an initiator such as ethylene glycol, propylene glycol, diethylene glycol, glycerin, trimethylolpropane, ethylene diamine, and an alkylene oxide (e.g., ethylene oxide, propylene oxide, 1.2-1.3 - or 2,3-butylene oxide, tetrahydrofuran, styrene oxide, shrimp chlorohydrin, mixtures of two or more of these, etc.). Examples include those in which the terminal hydroxyl group is changed to an amino group by ammonolysis or the like.

Specific examples of polyoxyalkylene polyamines include those of the general formula derived from polypropylene glycol or triol, where n is about 2 to 50. ] or Cut 1O
cH*cH(CHa)-) X lll5CHs-CH
a-C-CHa (-00H*CH(CHa)-) 7
2IHa (If )\ CHa (-0CII*CH(CTo)-) Z jl
lls [where X+F+Z is about 3-50. ] Examples include polyoxypropylene polyamines represented by the following.

In the present invention, (poly)alkylene polyamines in oxyalkylene ether of (poly)alkylene polyamines include jetanolamine, triethanolamine, (poly)ethylene polyamines (e.g.
(poly)propylene polyamines (e.g. propylene diamine, dipropylene triamine).

tripropylenetetramine, etc.), (poly)cycloalkylene polyamines (e.g. 1.8-p-methanediamine, inphorondiamine, diaminocyclohexane, 4.
4'-methylenebisdicyclohexylamine, l,3-
bis(aminomethyl)cyclohexane, etc.). Among these, preferred are triethanolamine, ethylenediamine, diethylenetriamine, and dipropylenetriamine. Two or more of these polyalkylene polyamines may be used in combination. As the oxyalkylene ether of (poly)alkylene polyamine,
Examples include alkylene oxide adducts of this (poly)alkylene polyamine. Examples of the alkylene oxide include those mentioned in the above (2).

The alkylene oxides may be used alone or in combination of two or more, and in the latter case, block addition, random addition, or a mixture of both may be used. Among the alkylene oxides, preferred are ethylene oxide, propylene oxide, and combinations thereof. The molecular weight per hydroxyl group of the oxyalkylene ether of this (poly)alkylene polyamine is usually 30 or more, preferably 60 to 500. , the polyamide compound ■ is a monoamide compound and a polyamide compound (polyamide resin). The above-mentioned polymerized fatty acids, -basic acids and polyamines are
Those described in Publication No. 1 and Japanese Patent Publication No. 53-41122 can be used.

The amine value of mono- or polyamide-based compounds (■) is usually 9.
It is 0 or more, preferably 100-450, particularly preferably 150-400. Since those having an amine value of less than 90 generally have a high molecular weight, the compatibility with the blocked urethane prepolymer is reduced.

The mono- or polyamide-based compound ① may be a partially modified version thereof, such as one containing an imidacillin ring in the molecule, or the mono- or polyamide-based compound ③ may be a compound such as a vinyl compound having an electron-withdrawing group (acrylonitrile, epoxy acrylate, etc.). It also includes modified compounds that grow modified active amino groups (for example, those described in Japanese Patent Publication No. 51-23560 and Japanese Patent Publication No. 52-5554).

Furthermore, the mono- or polyamide-based compound (1) may contain free polyamine. Examples of this polyamine include aliphatic polyamines [alkylene (Cs-C4) diamines (ethylene diamine, propylene diamine, etc.)]
, polyalkylene polyamine (diethylenetriamine,
dipropylenetriamine, triethylenetetramine, etc.), aromatic polyamines (phenylenediamine, tolylenediamine, xylylenediamine, etc.), alicyclic polyamines (cyclohexylenediamine, inphoronediamine,
diaminodicyclohexylmethane, dimethyldiaminodicyclohexylmethane, etc.), heterocyclic polyamines [piperazine, aminoalkyl-substituted piperazine (aminoethylpiperazine, etc.), etc.], and mixtures of two or more of these. Regarding polyamines, see Japanese Patent Application Laid-open No. 1983-
Those described as polyamines in No. 122395 and JP-A-54-101899 can be used. Preferred among polyamines are polyalkylene polyamines.

In ketimine (1) of polyoxyalkylene polyamine, ketimine (2) of polyamide compound, and ketimine (2) of (poly)alkylene polyamine, examples of the polyoxyalkylene polyamine include the aforementioned polyoxypropylene diamine and polyoxypropylene triamine.

(Poly)alkylene polyamines include the aforementioned ethylenediamine, diethylenetriamine, propylenediamine,
Examples include hexamethylene diamine and (poly)cycloalkylene polyamines (for example, those mentioned in item (1) above).

Among these polyamines and polyamide compounds, polyoxyalkylene polyamines and polyamide compounds are preferred.

Ketimines of these polyamines and polyamide compounds include reaction products of polyamines and polyamide compounds with ketones. Examples of ketones include acetone, methyl ethyl ketone, methyl propyl ketone,
Examples include methyl isopropyl ketone, methyl isobutyl ketone, diethyl ketone, dipropyl ketone, diisopropyl ketone, dibutyl ketone, and diimbutyl ketone. Preferably it is methyl isobutyl ketone.

Ketimine can be produced by dehydration condensation of a polyamine or polyamide compound and a ketone. The above condensation reaction is usually carried out in the presence of a water absorbing agent while distilling off water. Specifically, a stoichiometric excess of ketone is added to a polyamine or polyamide compound, and an appropriate solvent (toluene, xylene, etc.) is added, followed by dehydration condensation under heating and reflux while separating water. It can be produced by removing excess ketone and solvent.

The epoxy-modified products of ■■■■■ and ■ include epoxidized fatty acid alkyl ester of polyoxypropylene triamine (epoxy-modified product of ), ketone condensation product of glycidyl ether adduct of polyoxypropylene triamine (epoxy modified product of ■), polymerized fatty acid, polyethylene polyamine, polycondensation metal of fatty acid and bisphenol A
Diglycidyl ether adduct (epoxy modified product of ■),
Examples include a ketone condensate of an epoxy-modified product ((2)) (epoxy-modified product ((2)), a condensate of a glycidyl ether adduct of polyethylene polyamine and a ketone ((2) an epoxy-modified product), and the like.

The curing agents may be used alone or in combination of two or more. Preferably, by using (1) and (2) in combination, paintability and yellowing can be further improved. Also,
By using (2) and (0) together, the curability and paintability can be further improved.

The curing agent is a mixture of ketimine of a polyamide compound and oxyalkylene ether of a (poly)alkylene polyamine, and a curing agent containing a polyamide compound has curability,
Preferable in terms of storage stability and paintability.

Catalysts that are commonly used (for example, organometallic compounds such as lead octylate and tin octylate) are used to reduce the heat treatment temperature or shorten the heat treatment time during paint application by promoting the reaction between the base resin and the curing agent during heating. , tertiary amine compounds such as triethylenediamine and triethylamine) can also be used in combination.

In the present invention, the equivalent ratio of NGO/active hydrogen between the base agent and the curing agent is usually 110.1 to 2, preferably 110.5 to 1.
．． It is 5. If the active hydrogen content is less than 0.1 or greater than 2, curing will be insufficient or chipping resistance will be poor.

Pigments, fillers and solvents may be added to the composition of the present invention, if necessary. Examples of pigments include inorganic pigments such as titanium oxide, carbon black, red iron oxide, and oxide yellow, and organic pigments such as phthalocyanine blue and phthalocyanine green.

Examples of fillers include clay calcium carbonate, barium sulfate, talc, alumina, silica, pallite, vermiculite, and clay.

Further, as the solvent, the same solvent as used in producing the urethane prepolymer can be used.

The composition of the present invention may also be applied to natural or synthetic resins such as cellulose derivatives, vinyl chloride resins, phenolic resins, ketone resins, synthetic rubbers, unsaturated polyester resins, epoxy resins, melamine resins, urea resins, and rosin resins. Various auxiliary agents such as anti-sagging agents, anti-sagging agents, anti-foaming agents, surfactants, hardening accelerators, anti-foaming agents, pigment dispersants, and antistatic agents can also be used.

An example of the formulation of the composition of the present invention is as follows. (% is based on the weight of the composition) Contains isocyanate groups Usually 20-90%
Urethane bucine reamer compound (preferably 30-70%) hardening agent
Usually 1-40% (preferably 2-30%) pigment and usually 5-80% filler
(preferably 1G-80%) solvent
Usually 10-70% (preferably 2
0-50%) Other formulations usually 1-20%
(preferably 1 to 10%) The composition of the present invention can be manufactured by a known method. For example, each of the above ingredients is mixed using a normal mixing device (disper triple roll,
It is obtained by mixing using a ball mill, steel mill, pebble mill, attritor, sand mill, sand grinder, roll mill, pot mill, high-speed stirrer with blades, etc., and making it into a paint.

The composition of the present invention can be applied directly to an untreated iron plate surface or a chemically-converted iron plate surface, directly to a galvanized iron plate surface, or to any surface such as an anionic electrodeposition coated surface or a cationic electrodeposition coated surface. Painted by method.

Coating can be performed using an air spray coating machine, an airless spray coating machine, a hot airless spray coating machine, or the like. It is preferable to use an airless spray coating machine because it takes time to obtain the required film thickness.

In the case of an airless spray paint machine, the required film thickness can usually be obtained in one or two strokes, depending on the stroke speed. Brush application, roller application, and spatula application can be used for repairing or applying to complex areas.

The baking temperature of the composition of the present invention is usually 90°C or higher, preferably 100-170°C, particularly preferably 110-150°C.
It is ℃. Baking time is usually within 120 minutes, preferably
It takes 10 to 60 minutes.

The dry film thickness formed by the composition of the present invention is usually 30~
500μ, preferably 50-300μ. Film thickness is 3
If it is less than 0μ, the chipping resistance is insufficient;
If it exceeds 0μ, problems such as underarms and sagging are likely to occur.

An intermediate coat is usually applied on the coating film formed from the composition of the present invention, and then a top coat is further applied.

The intermediate coating can be applied wet-on-wet even when the composition of the present invention is not dried, or it can be applied even when it is cured and dried. (Dry on Wet).

Intermediate coatings can be used to improve the gloss of the top coat and fill in fine irregularities on the surface of the coating, and epoxy resin paints, melamine alkyd resin paints, etc. are usually used. Examples of the coating method include a spray coating method and an electrostatic coating method. Also, the intermediate coating may be omitted in some cases.

Further, the top coat paint can be used for aesthetic purposes, and is usually a melamine alkyd resin paint, a thermosetting acrylic resin paint, or the like, and is applied in the same manner as the intermediate coat paint.

Wet-on the normal intermediate paint as described above.
After wet coating, it can be cured and dried at normal baking temperatures of about 120-170° C. without any pre-drying.

The composition of the present invention can be applied to a cured coating film of a base coat, and can also be used in any process such as on a cured intermediate coat coat or a cured topcoat coat.

EXAMPLES The present invention will be further explained with reference to Examples, but the present invention is not limited thereto.

Parts in Examples indicate parts by weight.

Example 1 2 parts of α, α, α, α-tetramethylxylylene diisocyanate 2B, 215 parts of polytetramethylene glycol (molecular weight = 1000), 729 parts of trimethylol propa, and 400 parts of carpitol acetate were heated at 8 o- The mixture was reacted for 5 hours at too much degree Celsius, and then 0.1 part of dibutyltin dilaurate was added, and the mixture was further reacted for 3 hours to obtain a urethane prepolymer with an NC0% of 8.9% (in terms of solid content). Next, 34 parts of MEK oxime was added and the mixture was further reacted at 80 to 80°C for 3 hours, after which it was confirmed by infrared absorption spectrum that the isocyanate group had disappeared.

In this way, a urethane prepolymer solution having a blocked isocyanate group and having a solid content of BO% was obtained. Using this urethane prepolymer solution having blocked isocyanate groups, a chipping-resistant coating composition was prepared at the following blending ratio.

Urethane prepolymer solution with blocked isocyanate groups 100 parts PO adduct of diethylenetriamine 3 parts (molecular weight:
400) Calcium carbonate 80 parts Titanium white 5 parts Carbon black 1 part Aromatic petroleum naphtha (boiling point range 100-200°C) 30 parts Next, apply an epoxy cationic electrodeposition paint, then bake it as a hardened anti-rust undercoat. The above-mentioned chipping-resistant coating composition was applied to the steel plate C on which the film was formed using an airless coating machine so that the film thickness after drying was 200μ, and the coating was applied under the conditions of 12G'CX for 15 minutes. Baking was done for hardening.

Example 2 Urethane prepolymer obtained in Example 1 (NCO%=
8.9. After adding 121 parts of ε-caprolactam (in terms of solid content) and reacting at 80 to 100°C for 3 hours, it was confirmed by infrared absorption spectrum that the isocyanate group had disappeared.

Then, 18 parts of carpitol acetate was added to reduce the solid content to BO.
A urethane prepolymer solution having % blocked isocyanate groups was obtained. Using this urethane prepolymer solution having blocked isocyanate groups, a chipping-resistant coating composition was prepared at the following blending ratio.

Urethane prepolymer having blocked inciato groups 100 parts Polyamide compound (total amine value 300) 19 parts (
Polymide L-504 (manufactured by Sanyo Chemical Industries, Ltd.) Calcium carbonate 80 parts Titanium white
5 parts carbon black 1 part aromatic petroleum naphtha (boiling range 100-200 DEG C.) 30 parts This anti-chip coating composition was baked and cured in the same manner as in Example 1.

Example 3 A chipping-resistant coating composition was prepared using the urethane prepolymer solution having blocked isocyanate groups of Example 1 at the following blending ratio.

Urethane prepolymer having blocked isocyanate groups 100 parts Ketimine, a polyamide compound 24 parts (total amine value 250) Calcium carbonate 80 Titanium white 5 parts Carbon black 1 part Aromatic petroleum naphtha (boiling range 100-200°C) 30 This anti-chip coating composition was baked and cured in the same manner as in Example 1.

Example 4 The procedure was carried out in the same manner as in Example 2, except that α, α, α-2α′-tetramethylxylylene diisocyanate in Example 2 was replaced with tolylene diisocyanate, except that the reaction temperature of tolylene diisocyanate was 70 to The temperature was 80°C. )
A urethane prepolymer solution having blocked isocyanate groups was obtained. A chipping-resistant paint composition was prepared in the same manner as in Example 1 using this urethane prepolymer solution that grows blocked isocyanate groups and the urethane prepolymer solution having blocked isocyanate groups obtained in Example 1. It was created and baked in the same way. The proportions of the urethane prepolymer solution having blocked isocyanate groups and the chipping-resistant composition are as follows.

[Urethane prepolymer solution having blocked isocyanate groups] Tolylene diisocyanate 2038B
Polytetramethylene glycol 234 parts (molecular weight = 1000) Trimethylolpropane 31 parts Carpitol acetate 400 parts ε-caprolactam 132 parts [Tipping-resistant composition Urethane prepolymer having co-blocked isocyanate groups (TDI type) 50 parts Blocked Urethane prepolymer (TMXDI type) that grows isocyanate groups 50 parts Ketimine, a polyamide compound 13 parts (total amine value 250) PO adduct of diethylenetriamine 5 parts (molecular weight = 400) Calcium carbonate 80 parts Titanium white 5 parts Carbon black 1 part Aromatic petroleum naphtha (boiling point range 100-200°C) 30 parts Comparative Example 1 The same procedure was carried out except that α, α, α′, α′-tetramethylxylylene diisocyanate in Example 1 was replaced with tolylene diisocyanate. The procedure was carried out in the same manner as in Example 1, except that the reaction temperature of tolylene diisocyanate was 70 to 80°C.

), a urethane prepolymer solution that grows blocked isocyanate groups was obtained. A chipping-resistant coating composition was prepared in the same manner as in Example 1 using this urethane prepolymer solution containing blocked isocyanate groups, and baked and cured in the same manner.

The baking has hardened. The proportions of the urethane prepolymer solution having blocked isocyanate groups and the chipping-resistant composition are as follows.

[Urethane prepolymer solution having blocked isocyanate groups cotolylene diisocyanate] 214N
248 parts of polytetramethylene glycol (
Molecular weight = 1000) Trimethylolpropane 33 parts Carpitol acetate 400 parts Methyl ethyl ketoxime 107 parts [Chipping-resistant composition] Urethane prepolymer having blocked isocyanate groups (TDI system) 100 parts Ketimine of polyamide compound 31 parts (total Amine value 250) Calcium carbonate 80 parts Titanium white 5 parts Carbon black 1 part Aromatic petroleum naphtha (boiling range 100-200°C) 3
0 parts Comparative Example 2 A urethane prepolymer solution having blocked isocyanate groups was obtained in the same manner as in Comparative Example 1 except that the blocking agent in Comparative Example 1 was changed from MEK oxime to ξ caprolactam (however, ξ The temperature for caprolactam blocking was 80 to 100°C). A chipping-resistant coating composition was prepared in the same manner as in Example 1 using this urethane prepolymer solution having blocked isocyanate groups and baked in the same manner, but no curing occurred.

The proportions of the urethane prepolymer solution having blocked isocyanate groups and the chipping-resistant composition are as follows.

[Urethane prepolymer solution having blocked isocyanate groups] Tolylene diisocyanate) 210 parts Polytetramethylene glycol 242 parts (molecular weight = 1000) Trimethylolpropane 32 parts Carpitol acetate 422 parts ξ-caprolactam 150 parts [
Anti-chip composition] Urethane prepolymer having blocked isocyanate groups 100 parts Ketimine, a polyamide compound 31 parts (total amine value 250) Calcium carbonate 80 parts Titanium white 5 parts Carbon black 1 part Aromatic petroleum naphtha (boiling point range) ioo~200℃) 3
0 parts Test Example 1 Baking of the chipping-resistant paint compositions obtained in Examples 1 to 4 and Comparative Example 1 was evaluated for coating adhesion, curability, paintability, chipping resistance, storage stability, and yellowing. The results are shown in Table-1.

Paint film test method Adhesion (gopan method) 100X 200u on 10080.8mmmm chisel plate
A cross-cut (area: 1 cm) at the corner was made on the sample coated with a thick (after drying) chipping-resistant paint composition and baked. Next, a peel test was performed using cellophane tape, and the adhesion/remaining coating was measured. The numerator shows the residual number, and the denominator shows the number initially cross-cut.

Curing 100X 100X 0.8mm] 201 on electrodeposition coated board
And apply a chipping-resistant paint composition to a thickness of 350μ (after drying) at 120℃×! Bake for 5 minutes. After cooling, the degree of tack was examined by touch with fingers.

0: No tack Δ: Slight tack, but not a problem for practical use
After spraying on an electrodeposition coated plate to a film thickness of 50 μm (after drying) and baking at 120° C. for 15 minutes, the appearance of the cured film (blister, wrinkles, etc.) was examined.

O: No blisters, underarms, etc. Δ: Some underarms are seen, but they are extremely small ×: Blisters, underarms, etc. occur.Chipping resistance: 2008 thickness (after drying) of anti-chipping paint composition applied to 100 x 100 x 0.8 mm electrodeposition coated board. The coated and baked sample is then coated with a commonly used intermediate coating (melamine,
After painting and baking (dry intermediate coating thickness: 30μ, baking conditions: 140℃ x 20 minutes), JI
A Tetsujin square nut of type 3-14 shape specified in S B-1181 was dropped from a height of 2 m through a tube with a diameter of 20 mg+ onto each sample plate at an angle of 45° to the direction of the nut's fall, and coated. Table 1 shows the total weight (Kg) of the nuts that fell until the scratches on the membrane reached the metal surface.

The storage-stable chipping-resistant paint composition was stored at 40°C for XIO days, and the viscosity increase rate (%) of the paint before and after storage was investigated.

Yellowing 150X 1G0 polypropylene tray was filled with 2 resin liquids from Examples 1 to 4 and Comparative Example 1 from which pigment components were removed.
A sample was prepared which was coated and baked to a thickness of 0.00 μm (after drying). Baking conditions are 120℃ x 15 minutes + 150℃
It was set as 40 minutes. The degree of yellowing of this sample was measured using a multi-light source spectrophotometer (
It was measured using Suga Test Instruments Co., Ltd.).

Estimated Yellowing> Effects of the Invention The coating composition of the present invention adheres and cures to the underlying electrodeposited film at a lower temperature and in a shorter time than conventional compositions, and has excellent paintability and chipping resistance. It has excellent corrosion resistance and storage stability.Therefore, it exhibits excellent rust prevention properties when applied to vehicles, etc.

In addition, one-component resin compositions consisting of urethane prepolymers that grow blocked isocyanate groups, polyol compositions, and monoalcohols are also known, but they were insufficient in terms of low-temperature curability and paintability. . but,
The composition of the present invention is also excellent in these respects.

Because of the above-mentioned effects, the coating composition of the present invention, particularly the chipping-resistant coating, is particularly useful for automobiles as a rust-preventing coating that can be expected to improve productivity.

Claims (1)

[Claims] 1. (1) Lactam compound of urethane prepolymer (a) having isocyanate groups from organic polyisocyanate containing α,α,α′,α′-tetramethylxylylene diisocyanate and polyols A main agent consisting of a blocked product (a_1) and/or a blocked product (a_2) with an oxime compound; (2) polyoxyalkylene polyamine [1], oxyalkylene ether of (poly)alkylene polyamine [2], polyoxyalkylene polyamine A curing agent selected from the group consisting of ketimine [3], polyamide compound [4], ketimine of polyamide compound [5], ketimine of (poly)alkylene polyamine [6], and epoxy modified products thereof [7]. A paint composition comprising: 2. Blocked product (b_1) with a lactam compound and/or blocked product with an oxime compound (b_1) of a urethane prepolymer whose main ingredients have (a_1) and/or (a_2) and isocyanate groups from aromatic polyisocyanate and polyols ( The composition according to claim 1, comprising b_2). 3. The composition according to claim 2, containing 80% or less of 3, (b_1) and/or (b_2) based on the total weight of the main ingredients. 4. The composition according to any one of claims 1 to 3, wherein the curing agent is a mixture of ketimine of a polyamide compound and oxyalkylene ether of a (poly)alkylene polyamine. 5. Claims 1 to 4, wherein the curing agent contains a polyamide compound.
A composition according to any one of the above.