JPS598306B2 - Netsukoukaseihifufussaibutsu - Google Patents

Description

【発明の詳細な説明】 本発明は、水溶性熱硬化型アクリル樹脂を乳化剤として
Ｎ−メチロール（メタ）アクリルアミドおよび／または
Ｎ−アルコキシメチル（メタ）アクリルアミドを含むビ
ニル単量体を乳化重合させて得られる重合体水性分散液
とアミノ樹脂とからなる機械的性質、耐水性、耐薬品性
などの著しく改良された焼付塗膜を与え、しかも揮発分
中の有機溶剤量が少ないため大気汚染、水質汚染防止に
効果的な熱硬化型水性被覆組成物に関するものである。Detailed Description of the Invention The present invention involves emulsion polymerization of vinyl monomers containing N-methylol (meth)acrylamide and/or N-alkoxymethyl (meth)acrylamide using a water-soluble thermosetting acrylic resin as an emulsifier. The resulting aqueous polymer dispersion and amino resin provide a baked coating film with significantly improved mechanical properties, water resistance, and chemical resistance, and because the amount of organic solvent in the volatile component is small, it reduces air pollution and water quality. The present invention relates to a thermosetting aqueous coating composition that is effective in preventing contamination.

従来、大気汚染防止などの公害対策として熱硬化型の水
性塗料が使用されているが、この水性塗料を大別すると
樹脂成分が水中に分散している水分散型と、水中に溶解
している水溶液型の２種類になるが現段階ではいずれも
満足すべきものがなく、いくつかの欠点をもつている。Conventionally, thermosetting water-based paints have been used as a pollution control measure such as air pollution prevention, but these water-based paints can be roughly divided into water-dispersed types, in which the resin component is dispersed in water, and those in which the resin component is dissolved in water. There are two types of aqueous solutions, but at this stage, neither of them is satisfactory and has several drawbacks.

たとえば、本発明が目的とする水分散型水性塗料におい
ては生成塗膜の光沢が劣ること、乳化剤として用いられ
る界面活性剤が塗膜中に残存するため耐水性、耐候性が
満足でないこと、および水溶性アミノ樹脂等の架橋剤を
併用しても水性分散液中の分散粒子との融合、均一な混
合が不十分なために硬化性が足りず一般に耐水性および
耐藩剤性が悪いことがあげられる。本発明は、上記の問
題点を解消するためになされたものであり、特に、従来
の界面活性剤を用いた乳化重合体の水性塗料における上
記の欠点を改良すべく種々研究した結果、アクリル酸お
よび／またはメタクリル酸、アクリル酸ヒドロキシアル
キルおよび／またはメタクリル酸ヒドロキシアルキル、
およびこれらと共重合可能なモノエチレン系不飽和単量
体を共重合せしめ中和して得られる水溶性共重合体がす
ぐれた乳化剤となり得ることを知見したのである。For example, in the water-dispersed water-based paint that is the object of the present invention, the gloss of the resulting paint film is poor, the surfactant used as an emulsifier remains in the paint film, and the water resistance and weather resistance are unsatisfactory. Even if a crosslinking agent such as a water-soluble amino resin is used in combination, fusion with the dispersed particles in the aqueous dispersion and uniform mixing are insufficient, resulting in insufficient curing properties and generally poor water resistance and chemical resistance. can give. The present invention was made to solve the above-mentioned problems, and in particular, as a result of various studies to improve the above-mentioned drawbacks of conventional emulsion polymer water-based paints using surfactants, acrylic acid and/or methacrylic acid, hydroxyalkyl acrylate and/or hydroxyalkyl methacrylate,
They discovered that a water-soluble copolymer obtained by copolymerizing and neutralizing a monoethylenically unsaturated monomer copolymerizable with these monomers can be an excellent emulsifier.

さらに、該水洛性共重合体を乳化剤とした水性分散液中
の分散粒子内に自己架橋性を有する−Ｃ−ＮＨ−ＣＨ２
Ｏ−Ｈあるいは−Ｃ−ＮＨ−ＣＨ２Ｏ−ＣｎＨ２Ｏ＋１
（ｎは１〜４の数字を示す。）で表わされる自己架橋性
官能基を導入することにより外部架橋剤であるアミノ樹
脂と該水性分散液中の該分散粒子が完全に融合、混合し
ない場合でも、該分散粒子中で前記自己架橋性官能基同
志あるいは、該分散粒子中に必要に応じて加えられたヒ
ドロキシアルキル基との間の架橋反応により架橋網目構
造を形成でき、また該分散粒子中の前記自己架橋性官能
基が、乳化剤（水溶性共重合体）中のヒドロキシアルキ
ル基、および／または外部架橋剤である水溶性メラミン
樹脂との間で架橋反応し、緻密な三次元網目構造が形成
できるため、高度の硬化性と耐水性、耐溶剤性、耐化学
薬品性を示す塗膜が得られることを見い出し、下記本発
明に到達したものである。この乳化剤を用いて製造した
重合体水性分散液にアミノ樹脂を配合し、架橋触媒の存
在または不存在下に被膜を形成せしめ加熱処理すれば、
乳化剤間はもちらん、重合体（分散粒子）間、および乳
化剤と重合体との間で架橋反応が起こるため、高度な耐
水性、耐溶剤性を与えることができ、しかも大気汚染対
策に貢献するとともに現行の水溶液型塗料では限界のあ
る塗装時の不揮発分を上げることができ、塗装作業性良
好な塗料を提供するものである。すなわち、本発明はア
クリル酸ヒドロキシアルキルおよび／またはメタクリル
酸ヒドロキシアルキル５〜６０重量？、アクリル酸およ
び／またはタクリル酸５〜２０重量？、およびアクリル
酸アルキルエステル、メタクリル酸アルキルスチル、ス
チレンおよびスチレン誘導体から選ばれる少くとも比重
の共重合可能なモノ′ｏ−，チレン系不飽和単量体２０
〜９０重量？を共重合せしめ中和して得られる水浩性共
重合体を乳化剤として、次の一般式（式中Ｒは水素原子
またはメチル基、Ｒ′は水素原子または、ＣｎＨ２Ｏ＋
１でｎは１〜４の数字を示す。Furthermore, -C-NH-CH2 having self-crosslinking properties within the dispersed particles in the aqueous dispersion using the hydrophilic copolymer as an emulsifier.
O-H or -C-NH-CH2O-CnH2O+1
(n is a number from 1 to 4) When the amino resin as an external crosslinking agent and the dispersed particles in the aqueous dispersion do not completely fuse and mix by introducing a self-crosslinking functional group represented by (n represents a number from 1 to 4) However, a crosslinked network structure can be formed in the dispersed particles by a crosslinking reaction between the self-crosslinkable functional groups or with a hydroxyalkyl group added as necessary to the dispersed particles, and The self-crosslinkable functional group undergoes a crosslinking reaction with the hydroxyalkyl group in the emulsifier (water-soluble copolymer) and/or the water-soluble melamine resin as an external crosslinker, resulting in a dense three-dimensional network structure. The inventors have discovered that the present invention described below can be obtained by forming a coating film that exhibits high curability, water resistance, solvent resistance, and chemical resistance. If an amino resin is blended into an aqueous polymer dispersion prepared using this emulsifier, a film is formed in the presence or absence of a crosslinking catalyst, and heat treatment is performed.
Crosslinking reactions occur not only between emulsifiers, but also between polymers (dispersed particles) and between emulsifiers and polymers, providing a high degree of water resistance and solvent resistance, and contributing to air pollution control. At the same time, it is possible to increase the non-volatile content during painting, which is limited by the current aqueous solution type paints, and provides a paint with good painting workability. That is, the present invention uses 5 to 60 hydroxyalkyl acrylates and/or hydroxyalkyl methacrylates by weight. , acrylic acid and/or tacrylic acid 5-20% by weight? , and a copolymerizable mono'o-, tyrenic unsaturated monomer with a specific gravity of at least 20 selected from acrylic acid alkyl esters, alkyl styrene methacrylates, styrene and styrene derivatives.
~90 weight? The water-porous copolymer obtained by copolymerizing and neutralizing is used as an emulsifier, and the following general formula (wherein R is a hydrogen atom or a methyl group, R' is a hydrogen atom or a CnH2O+
1 and n indicates a number from 1 to 4.

）で表わされる架橋性不飽和化合物５〜５０重量？、お
よびビニル単量体５０〜９５重量？からなる単量体混合
物を乳化重合せしめた耐水性のすぐれた皮膜を形成する
ことのできる安定な重合体水性分散液囚とアミノ樹脂（
６）とを固形分換算で（Ａ）／０３）一９５／５〜６０
／４０の割合で配合したもので、かつ、それに含有され
る揮発性物質中の有機藩剤の量が３〜３０％であること
を特徴とする熱硬化性被覆組成物である。本発明におい
て用いる重合体水性分散液（４）の乳化剤の第１成分で
あるアクリル酸ヒドロキシアルキルおよびメタクリル酸
ヒドロキシアルキルとしては、アクリル酸２−ヒドロキ
シエチル、メタクリル酸２−ヒドロキシエチル、アクリ
ル酸２−ヒドロキシプロピル、メタクリル酸２−ヒドロ
キシプロピルなどが使用できる。5 to 50 weight of crosslinkable unsaturated compound represented by )? , and vinyl monomer 50-95% by weight? A stable polymer aqueous dispersion that can form a highly water-resistant film by emulsion polymerization of a monomer mixture consisting of an amino resin (
6) and (A)/03)-95/5-60 in terms of solid content
This is a thermosetting coating composition characterized in that it is blended at a ratio of: The hydroxyalkyl acrylate and hydroxyalkyl methacrylate that are the first component of the emulsifier in the aqueous polymer dispersion (4) used in the present invention include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, and 2-hydroxyalkyl acrylate. Hydroxypropyl, 2-hydroxypropyl methacrylate, etc. can be used.

また、該乳化剤の第３成分、すなわち第１成分および第
２成分（アクリル酸および／またはメタクリル酸）と共
重合せしめて水藩性共重合体を形成し得るモノエチレン
系不飽和単量体としては、アクリル酸アルキルエステル
（たとえば、アクリル酸メチル、アクリル酸エチル、ア
クリル酸プロピル、アクリル酸ｎ−ブチル、アクリル酸
イソブチル、アクリル酸２−エチルヘキシル、アクリル
酸ラウリル、アクリル酸シクロヘキシルなど）、メタク
リル酸アルキルエステル（たとえば、メタクリル酸メチ
ル、メタクリル酸エチル、メタクリル酸プロピル、メタ
クリル酸ｎ−ブチル、メタクリル酸イソブチル、メタク
リル酸２−エチルヘキシル、メタクリル酸ラウリル、メ
タクリル酸シクロヘキシルなど）スチレン、置換スチレ
ン類などをあげることができる。In addition, as a monoethylenically unsaturated monomer that can be copolymerized with the third component of the emulsifier, that is, the first component and the second component (acrylic acid and/or methacrylic acid) to form a water-based copolymer. is an alkyl acrylate ester (e.g., methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, cyclohexyl acrylate, etc.), alkyl methacrylate Esters (for example, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, cyclohexyl methacrylate, etc.), styrene, substituted styrenes, etc. I can do it.

該乳化剤において上記第１成分は５〜６０重量ｅ、好ま
しくは１０〜４０重量？用いるのが適当であり、５重量
？より少ないと架橋性の低下により、また６０重量％よ
り多いと親水性基の増大によりいずれも塗膜の耐水性が
劣る。In the emulsifier, the amount of the first component is 5 to 60% by weight, preferably 10 to 40% by weight. Is it appropriate to use 5 weight? If the amount is less than 60% by weight, the crosslinking property will decrease, and if it is more than 60% by weight, the number of hydrophilic groups will increase, resulting in poor water resistance of the coating film.

さらに、第２成分は５〜２０重量％の範囲内で用いる必
要があり、第２成分の量およびその中和量により重合体
水性分散液の分散粒子径を任意に調節することが可能で
ある。第２成分が５重量？より少ない場合には、安定な
重合体水性分散液が得られず、また２０重量？より多い
と得られた重合体水性分散液は粘稠となり、やはり安定
性に劣る。本発明で使用する乳化剤は、上記した割合か
らなる第１〜３成分を有機洛剤中で適当な重合開始剤を
用いて公知の方法で共重合せしめ、中和することによつ
て得られる。Furthermore, the second component must be used within a range of 5 to 20% by weight, and the dispersed particle size of the aqueous polymer dispersion can be arbitrarily adjusted by the amount of the second component and its neutralization amount. . The second component is 5 weight? If the amount is less than 20% by weight, a stable aqueous polymer dispersion cannot be obtained. When the amount is larger, the resulting aqueous polymer dispersion becomes viscous and also has poor stability. The emulsifier used in the present invention can be obtained by copolymerizing the first to third components having the above-mentioned proportions in an organic reagent using a suitable polymerization initiator by a known method, and neutralizing the copolymer.

ここに用いる有機溶剤としてはメチルアルコール、エチ
ルアルコール、イソプロピルアルコール、ブチルアルコ
ールなどのアルコール系醇剤、メチルセロソルブ、セロ
ソルブ、ブチルセロソルブ、メチルカルビトール、カル
ビトール、ブチルカルビトールなどのエーテルアルコー
ル系溶剤、メチルセロソルブアセテート、セロソルブア
セテートなどのエステル系溶剤、アセトンなどのケトン
系溶剤など水と自由に混和し得る洛剤が用いられる。ま
た、重合開始剤としてはアゾビスイソブチロニトリルな
どのアゾ系化合物、過酸化ベンゾイルなどの過酸化物、
過安息香酸ｔ−ブチルのような過酸エステル、過硫酸ア
ンモニウムなどの過硫酸塩、有機過酸化物と鉄塩などの
レドツクス系を用いることができる。さらに、かかる共
重合体に若干の不飽和基を導入することが可能であり、
導入した不飽和基は乳化重合において共重合反応に参加
し得るためより安定性の良好な重合体水性分散液を得る
ことができる。Examples of organic solvents used here include alcoholic solvents such as methyl alcohol, ethyl alcohol, isopropyl alcohol, butyl alcohol, ether alcohol solvents such as methyl cellosolve, cellosolve, butyl cellosolve, methyl carbitol, carbitol, butyl carbitol, and methyl alcohol. Liquid agents that are freely miscible with water are used, such as cellosolve acetate, ester solvents such as cellosolve acetate, and ketone solvents such as acetone. In addition, as polymerization initiators, azo compounds such as azobisisobutyronitrile, peroxides such as benzoyl peroxide,
Peresters such as t-butyl perbenzoate, persulfates such as ammonium persulfate, and redox systems such as organic peroxides and iron salts can be used. Furthermore, it is possible to introduce some unsaturated groups into such copolymers,
Since the introduced unsaturated groups can participate in the copolymerization reaction during emulsion polymerization, it is possible to obtain a more stable aqueous polymer dispersion.

不飽和基導入の方法としては、たとえば該共重合体中の
カルボキシル基の一部に反応する量のメタクリル酸グリ
シジルを塩基性触媒の存在下に反応させることによりメ
タクリル基を共重合体側鎖に導入できる。このようにし
て得られた共重合体醇液から、適当量の有機溶剤を常圧
下または減圧下で留去した後、該共重合体を塩基性物質
の添加により少なくともカルボキシル基の５０％以上中
和した後、水で所望の濃度に希釈することによつて、本
発明で用いる重合体水性分散液の乳化剤が得られる。As a method for introducing unsaturated groups, for example, methacrylic groups are introduced into the side chains of the copolymer by reacting an amount of glycidyl methacrylate that reacts with a portion of the carboxyl groups in the copolymer in the presence of a basic catalyst. can. After distilling off an appropriate amount of the organic solvent from the copolymer solution obtained in this manner under normal pressure or reduced pressure, the copolymer is prepared by adding a basic substance to the solution containing at least 50% of the carboxyl groups. After mixing, the emulsifier for the aqueous polymer dispersion used in the present invention is obtained by diluting with water to a desired concentration.

この場合、中和量は７０％以上が好ましく、用いる塩基
性物質としては、アンモニア、メチルアミン、ジメチル
アミン、トリメチルアミン、エチルアミゾ、ジエチルア
ミン、トリエチルアミン、ジメチルエタノールアミン、
ジエタノールアミン、トリエタノールアミンなどがある
。本発明において用いる重合体水性分散液は、かかる水
溶性共重合体を乳化剤として、自己架橋性単量体お゛よ
びビニル単量体からなる単量体混合物を乳化重合せしめ
ることによつて得られる。In this case, the amount of neutralization is preferably 70% or more, and the basic substances used include ammonia, methylamine, dimethylamine, trimethylamine, ethylamizo, diethylamine, triethylamine, dimethylethanolamine,
These include diethanolamine and triethanolamine. The aqueous polymer dispersion used in the present invention is obtained by emulsion polymerization of a monomer mixture consisting of a self-crosslinking monomer and a vinyl monomer using such a water-soluble copolymer as an emulsifier. .

該自己架橋性単量体は、次９一般式（式中Ｒは水素原子
またはメチル基、Ｒ′は水素原子または、ＣｎＨ２ｎ＋
１でｎは１〜４の数字を示す。The self-crosslinking monomer has the following general formula (where R is a hydrogen atom or a methyl group, R' is a hydrogen atom or a CnH2n+
1 and n indicates a number from 1 to 4.

）で表わされるＮ−メチロール（メタ）アクリルアミド
および／またはＮ−アルコキシメチル（メタ）アクリル
アミドであつてたとえば、Ｎ−メチロールアクリルアミ
ド、Ｎ−メチロールメタクリルアミド、Ｎ−ブトキシメ
チルアクリルアミド、Ｎーブトキシメチルメタクリルア
ミドなどの自己架橋性単量体をあげることができ、その
量は単量体混合物中５〜５０重量？、好ましくは５〜３
０重量％が適当である。該自己架橋性単量体が５重量？
より少ない場合には、機械的性質、耐水性、耐薬品性の
著しく改良された焼付塗膜を得るという本発明の目的を
達成できないし、また５０重量％より多いと、塗膜の機
械的性質および耐水性が低下する。また、該重合体水性
分散液を得るために前記一般式で示される自己架橋性単
量体と共使用し得る該ビニル単量体としては、前記乳化
剤の第３成分として総称したモノエチレン系不飽和単量
体として用いられる単量体の他に、アクリル酸、メタク
リル酸、アクリル酸ヒドロキシアルキル、メタクリル酸
ヒドロキシアルキルなどもあげることができる。) and/or N-alkoxymethyl (meth)acrylamide, such as N-methylol acrylamide, N-methylol methacrylamide, N-butoxymethyl acrylamide, N-butoxymethyl methacrylamide The amount of self-crosslinking monomers such as 5 to 50% by weight in the monomer mixture can be mentioned. , preferably 5-3
0% by weight is suitable. 5 weight of the self-crosslinking monomer?
If the amount is less than 50% by weight, the objective of the present invention of obtaining a baked coating film with significantly improved mechanical properties, water resistance, and chemical resistance cannot be achieved, and if the amount is more than 50% by weight, the mechanical properties of the coating film are deteriorated. and water resistance decreases. In addition, the vinyl monomer that can be used together with the self-crosslinking monomer represented by the above general formula in order to obtain the aqueous polymer dispersion includes the monoethylene monomers collectively referred to as the third component of the emulsifier. In addition to the monomers used as saturated monomers, acrylic acid, methacrylic acid, hydroxyalkyl acrylate, hydroxyalkyl methacrylate, etc. can also be mentioned.

本発明で用いる重合体水性分散液を製造するには、前記
乳化剤と単量体混合物とを固形分換算重量比で前者：後
者−５：９．５−４０：６０の割合で使用して、通常の
乳化重合法に従つて行なう。In order to produce the aqueous polymer dispersion used in the present invention, the emulsifier and the monomer mixture are used in a solid content weight ratio of the former:the latter -5:9.5-40:60, This is carried out according to the usual emulsion polymerization method.

なお、必要に応じて乳化重合に通常用いられる界面活性
剤を性能を低下させない範囲で該乳化剤と併用すること
もできる。かくして得られた重合体水性分散液は、機械
的安定性、熱安定性にすぐれており、貯蔵安定性が良好
である。Incidentally, if necessary, a surfactant commonly used in emulsion polymerization may be used in combination with the emulsifier as long as the performance is not deteriorated. The aqueous polymer dispersion thus obtained has excellent mechanical stability, thermal stability, and good storage stability.

該重合体水性分散液に配合すべきアミノ樹脂としては種
々の構造のものが用いられるが、たとえば、ジ一、トリ
一、テトラ一、ベンダー、あるいはヘキサメチロールメ
ラミンおよびその誘導体、尿素−ホルムアルデヒド縮合
物、尿素一メラミン共縮合樹脂、ベンゾグアナミンなど
をあげることができるが、特にメラミン樹脂が好ましい
。The amino resin to be blended into the aqueous polymer dispersion may have various structures, including di-, tri-, tetra-, bender, hexamethylolmelamine and its derivatives, and urea-formaldehyde condensates. , urea-melamine cocondensation resin, benzoguanamine, etc., and melamine resin is particularly preferred.

アミノ樹脂０３）の配合量は、該重合体水性分散液囚に
対して固形分換算重量比で（Ａ）／８−９５／５〜６０
／３０であり特に（Ａ）／（Ｂ）＝９０／１０，〜７０
／３０の範囲が好ましい。この範囲外の配合では、いず
れも耐水性、耐溶剤性などの塗膜性能に欠陥を生じ本発
明の目的を達成しない。本発明による重合体水性分散液
は顔料に対し親和力があるのが、顔料分散剤としての他
の公知の水洛性樹脂を特に必要としないが、本発明の重
合体水性分散液１００重量部（固形分）に対して５０重
量部以内の割合で添加してもさしつかえない。The blending amount of amino resin 03) is (A)/8-95/5 to 60 in solid content weight ratio to the polymer aqueous dispersion.
/30, especially (A)/(B)=90/10, ~70
A range of /30 is preferred. Any formulation outside this range will result in defects in coating film performance such as water resistance and solvent resistance, and the object of the present invention will not be achieved. The aqueous polymer dispersion of the present invention has an affinity for pigments, and does not require any other known water-soluble resin as a pigment dispersant. It may be added in an amount of up to 50 parts by weight based on the solid content.

さらに本発明の組成物の特徴の一つは、該組成物に含ま
れる揮発性物質中の有機溶剤の含有量を３〜３０重量？
にできたことにある。Furthermore, one of the characteristics of the composition of the present invention is that the content of organic solvent in the volatile substances contained in the composition is 3 to 30% by weight.
This is because we were able to do so.

有機浩剤の割合がこの範囲にあることにより、大気汚染
防止上特に問題ない。ここで揮発性物質とは沸点が常圧
で３００℃以下の物質をさし、具体的には水および有機
溶剤がこれにあたる。有機溶剤としては前記乳化剤を製
造する場合に用いられるものがあげられる。本発明の組
成物には必要に応じて、各種の無機顔料および有機顔料
、各種の充てん剤、添加剤などを配合することができる
。If the proportion of the organic bulking agent is within this range, there will be no particular problem in preventing air pollution. Here, volatile substances refer to substances with a boiling point of 300° C. or lower at normal pressure, and specifically include water and organic solvents. Examples of the organic solvent include those used in producing the emulsifier. The composition of the present invention may contain various inorganic and organic pigments, various fillers, additives, and the like, as required.

本発明の組成物を塗装する方法としては、ハケ塗り、浸
漬塗り、スプレー塗装、ローラー塗装、または電着塗装
など、周知の各種塗装方法が用いられる。As a method for coating the composition of the present invention, various well-known coating methods such as brush coating, dip coating, spray coating, roller coating, or electrodeposition coating can be used.

本発明の組成物は塗装後、加熱により硬化せしめる。After coating, the composition of the present invention is cured by heating.

加熱硬化の条件は該組成物中の架橋性官能基の含有量、
膜厚、有機溶剤の種類などにより異なるが、通常８０〜
２５０℃、好ましくは１００〜１８０℃の温度範囲の適
当な温度で、１０〜６０分加熱処理することにより、耐
水性、耐爵剤性のすぐれた塗膜を形成させ得る。なお、
予め該組成物中にＮＨ４Ｃｌ，ＮＨ４ＮＯ３，（ＮＨ４
）２ＨＰ０４，（ＣＯＯＨ）２、Ｐ−トルエンスルホン
酸などの通常の架橋触媒を該組成物の固形分に対して０
，５〜１．０重量ｅ添加配合すると、加熱硬化条件を低
下させるのに有効である。The conditions for heat curing are the content of crosslinkable functional groups in the composition,
It varies depending on the film thickness, type of organic solvent, etc., but usually 80~
By heat treating at an appropriate temperature in the range of 250° C., preferably 100° C. to 180° C. for 10 to 60 minutes, a coating film with excellent water resistance and resistance to staining agents can be formed. In addition,
NH4Cl, NH4NO3, (NH4
)2HP04, (COOH)2, P-toluenesulfonic acid, etc. at 0% relative to the solids content of the composition.
, 5 to 1.0 weight e is effective in lowering the heat curing conditions.

本発明の特徴とするところは、水醇性熱硬化型アクリル
樹脂を乳化剤として自己架橋性単量体を乳化重合せしめ
た重合体水性分散液を用いること、および本発明の組成
物における揮発性物質中の有機溶剤の含有量を３〜３０
重量？に低減できたことにあり、これらによつて従来の
水性焼付塗料の欠点のいくつかを改良できた。すなわち
、前者により先述したように高度な耐水性、耐薬品性を
有する塗膜が得られるものである。また後者により揮発
性物質中の有機溶剤の量を少なくすることができたため
、現行の水溶液型塗料では溶液粘度を低下させる目的で
、しばしば多量の有機洛剤を使用する場合に比べ、大気
汚染防止に著しく効果的である。さらに、従来の乳化重
合体を用いたものとの比較で本発明により得られる組成
物の効果を説明すると次のようになる。まず、従来の乳
化重合法により得られた塗料では、界面活性剤が塗膜中
に残存するため塗膜の耐水性、耐候性が満足でなく、ま
た光沢も劣つている。The present invention is characterized by the use of an aqueous polymer dispersion prepared by emulsion polymerization of a self-crosslinking monomer using a water-soluble thermosetting acrylic resin as an emulsifier, and the use of a volatile substance in the composition of the present invention. The content of organic solvent in the
weight? As a result, some of the drawbacks of conventional water-based baking paints can be improved. That is, the former provides a coating film having high water resistance and chemical resistance as described above. The latter also reduces the amount of organic solvents in volatile substances, making it more effective at reducing air pollution compared to current aqueous paints, which often use large amounts of organic solvents to reduce solution viscosity. It is extremely effective. Furthermore, the effects of the composition obtained by the present invention in comparison with those using conventional emulsion polymers are explained as follows. First, in paints obtained by conventional emulsion polymerization methods, surfactants remain in the paint film, so the water resistance and weather resistance of the paint film are unsatisfactory, and the gloss is also poor.

しかし、本発明による組成物における重合体水性分散液
の製造においては通常の界面活性剤を使用する必要がな
く、しかも得られる重合体水性分散液の粒子径が極めて
小さいため、上述の欠点はない。さらに、従来の水溶液
型塗料が、基体樹脂の水醇化のために多量のカルボキシ
ル基を必要とし、これらは塗膜中に残存して耐アルカリ
性、耐水性、耐候性の不良という欠点につながつていた
が、これに対して本発明の重合体水性分散液は全体に対
するカルボキシル基の量が少なくてすみ、上述のような
欠点はほとんど生じない。However, in the production of the aqueous polymer dispersion in the composition according to the invention, there is no need to use conventional surfactants, and the particle size of the aqueous polymer dispersion obtained is extremely small, so that the above-mentioned disadvantages are not present. . Furthermore, conventional aqueous paints require a large amount of carboxyl groups to make the base resin water-soluble, and these remain in the paint film, leading to drawbacks such as poor alkali resistance, water resistance, and weather resistance. However, on the other hand, the aqueous polymer dispersion of the present invention requires only a small amount of carboxyl groups relative to the total amount, and the above-mentioned drawbacks hardly occur.

さらに、現行の水溶液型塗料では限界のある塗装時の不
揮発分を上げることが可能となり、塗装作業性も良好と
なるＯ以下実施例では本発明を説明する。Furthermore, it is possible to increase the non-volatile content during coating, which is limited by the current aqueous solution type paints, and the coating workability is also improved.The present invention will be explained in the following examples.

実施例およ比較例中、％は重量％を表わす。実施例 １ を、１２０℃に加熱した１００重量部のセロソルブ中に
適下し、７時間かけて重合を行なつた後、有機溶剤７０
重量部を留去させ、トリエチルアミンで当量中和し、水
を加えて１５％の水酪液にした。In Examples and Comparative Examples, % represents weight %. Example 1 was dropped into 100 parts by weight of cellosolve heated to 120°C, polymerized for 7 hours, and then 70 parts by weight of an organic solvent was added.
Parts by weight were distilled off, an equivalent amount was neutralized with triethylamine, and water was added to make a 15% milky water solution.

この水溶液１００重量部に、を加えて１時間撹拌した後
、過硫酸アンモニウム１重量部を水５重量部に溶かして
加え、７５℃で４時間加熱したところ固形分４５％で粘
度１３０センチポイズの重合体水性分散液が得られた。To 100 parts by weight of this aqueous solution was added and stirred for 1 hour, then 1 part by weight of ammonium persulfate dissolved in 5 parts by weight of water was added and heated at 75°C for 4 hours, resulting in a polymer with a solid content of 45% and a viscosity of 130 centipoise. An aqueous dispersion was obtained.

この分散液は４０℃で１力月間放置しても粘度の変化が
なく、凝集物もできず安定であつた。この重合体水性分
散液１６３重量部にメチル化メチロールメラミンの１種
であるＨＭ−１００（８０％ブチルセロソルブ酪液）〔
住友化学工業（株）製商品名〕３７重量部、ブチルセロ
ソルブ１０重量部を加えて作製した塗料を水で希釈して
フオードカツプ＃４で３０秒にしたところ、固形分３４
％、揮発性物質中の有機浩剤量１１％であつた。これを
鉄板にスプレー塗装し１４０℃で３０分間焼付けた。実
施例 ２実施例１で得られた重合体水性分散液２０９重
量部にブトキシメチル化メラミンの１種であるユーバン
２０ＳＥ（５０％ｎ−ブタノール／キシロール混合洛液
）〔三井東圧化学（株）製商品名〕１０重量部、ブチル
セロソルブ１０重量部を加えて作製した塗料を水で希釈
してフオードカツプ＃４で３０秒にしたところ固形分３
６％、揮発性物質中の有機溶剤量１２％であつた。This dispersion did not change in viscosity even after being left at 40° C. for one month, and remained stable without forming any aggregates. HM-100 (80% butyl cellosolve dairy liquor), which is a type of methylated methylol melamine, was added to 163 parts by weight of this aqueous polymer dispersion.
When a paint prepared by adding 37 parts by weight of Sumitomo Chemical Co., Ltd. product name and 10 parts by weight of butyl cellosolve was diluted with water and heated in a #4 food cup for 30 seconds, the solid content was 34.
%, and the amount of organic thickener in volatile substances was 11%. This was spray painted on an iron plate and baked at 140°C for 30 minutes. Example 2 209 parts by weight of the aqueous polymer dispersion obtained in Example 1 was added to Yuban 20SE (50% n-butanol/xylol mixed solution), which is a type of butoxymethylated melamine (Mitsui Toatsu Chemical Co., Ltd.) When a paint prepared by adding 10 parts by weight of product name] and 10 parts by weight of butyl cellosolve was diluted with water and heated in a food cup #4 for 30 seconds, the solid content was 3.
6%, and the amount of organic solvent in volatile substances was 12%.

これを鉄板に塗装し、１５『Ｃで３０分間焼付けた。実
施例 ３ を、１２０℃に加熱した１００重量部のセロソルブ中に
滴下し、７時間かけて重合を行なつた後、后剤８０重量
部を留去し、トリエチルアミンで当量中和して水を加え
２５％の水爵液を作る。This was painted on an iron plate and baked at 15°C for 30 minutes. Example 3 was added dropwise to 100 parts by weight of cellosolve heated to 120°C, and polymerization was carried out over 7 hours. After that, 80 parts by weight of the stimulant was distilled off, and an equivalent amount of triethylamine was neutralized to remove water. Add to make 25% water bottle solution.

この水溶液８０重量部を用いてチタン白ＪＲ−６００Ｅ
〔帝国化工（株）製商品名〕１００重量部をボールミル
にて分散し、実施例１で用いた重合体水性分散液１１６
重量部、ＨＭ−１００を３７重量部を加えて塗料を作製
し、水で希釈してフオードカツプ＃４で３０秒にしたと
ころ固形分５１％、揮発性物質中の有機溶剤量７％であ
つた。これを鉄板にスプレー塗装したところ塗装作業性
がすぐれており、１４０℃で３０分間焼付けた。実施例
４ 実施例３で用いた２５％の水溶液８０重量部によりアル
ミ顔料５重量部を分散し、実施例１で用いた重合体水性
分散液１１６重量部、ＨＭ−１００を３７重量部、ブチ
ルセロソルブ１０重量部加えて塗料を作製し、水で希釈
してフオードカツプ＃４で３０秒にしたところ固形分３
５％、揮発性物質中の有機浩剤量１２％であつた。Titanium white JR-600E was prepared using 80 parts by weight of this aqueous solution.
[Product name manufactured by Teikoku Kako Co., Ltd.] 100 parts by weight was dispersed in a ball mill to obtain the polymer aqueous dispersion 116 used in Example 1.
A paint was prepared by adding 37 parts by weight of HM-100, diluted with water, and dried in a #4 food cup for 30 seconds.The solid content was 51%, and the amount of organic solvent in volatile substances was 7%. . When this was spray-painted on an iron plate, the coating workability was excellent, and it was baked at 140°C for 30 minutes. Example 4 5 parts by weight of aluminum pigment was dispersed with 80 parts by weight of the 25% aqueous solution used in Example 3, 116 parts by weight of the aqueous polymer dispersion used in Example 1, 37 parts by weight of HM-100, and butyl cellosolve. A paint was prepared by adding 10 parts by weight, diluted with water, and dried in a #4 food cup for 30 seconds, resulting in a solid content of 3.
5%, and the amount of organic thickening agent in volatile matter was 12%.

これを鉄板にスプレー塗装したところ塗装作業性がすぐ
れており、１４０℃で３０分間焼付けたところメタリツ
ク感にすぐれた塗膜が得られた。実施例 ５ を、加熱環流させた１００重量部のイソプロピルアルコ
ール中に滴下し、７時間かけて重合を行なつた後、后剤
７０重量部を留去させアンモニア水で当量中和し、水を
加えて２０％の水后液にした。When this was spray-coated on an iron plate, the coating workability was excellent, and when baked at 140°C for 30 minutes, a coating film with an excellent metallic feel was obtained. Example 5 was added dropwise to 100 parts by weight of isopropyl alcohol heated to reflux, and polymerization was carried out over 7 hours. After that, 70 parts by weight of the stimulant was distilled off, the equivalent amount was neutralized with aqueous ammonia, and the water was removed. In addition, it was made into a 20% hydration solution.

この水溶液１００重量部に、スチレン
１２重量部メタクリル酸イソブチル
１０重量部Ｎ−ブドキシメチルアクリルアミド ５重
量部ヒドロキシエチルメタクリレート ３重量部を加
えて１時間撹拌した後、過硫酸カリウム１重量部を水１
０重量部に溶かして加え７５℃で４時間加熱したところ
固形分３６％で粘度２２０センチポイズの重合体水性分
散液が得られた。Styrene was added to 100 parts by weight of this aqueous solution.
12 parts by weight isobutyl methacrylate
After adding 10 parts by weight of N-budoxymethylacrylamide and 5 parts by weight of hydroxyethyl methacrylate and stirring for 1 hour, 1 part by weight of potassium persulfate was added to 1 part by weight of water.
When the mixture was added in a solution of 0 parts by weight and heated at 75° C. for 4 hours, an aqueous polymer dispersion with a solid content of 36% and a viscosity of 220 centipoise was obtained.

この分散液は４０℃で１力月間放置しても粘度の変化が
なく、凝集物もできず安定であつた。この重合体水性分
散液１９４重量部にＨＭ−１００を３７重量部、ブチル
セロソルブ１０重量部加えて塗料を作製し、水で希釈し
てフオードカツプ＃４で３０秒にしたところ固形分３２
％、揮発性物質中の有機洛剤量１１％であつた。これを
鉄板に塗装し、１４０℃で３０分間焼付けた。実施例
６ ヒドロキシプロピルアクリレート ６０重量部アクリル
酸 ５重量部メタクリル酸メ
チル ３５重量部アゾビスイソブチロニト
リル １重量部を、１２０℃に加熱した１００重
量部のセロソルブ中に滴下し、７時間かけて重合を行な
つた後、グリシジルメタクリレート ２重量部ハイ
ドロキノン ０．０５重量部ジメチルアミ
ノエタノール ０．５重量部を加えてさらに６時間加
熱を続けた。This dispersion did not change in viscosity even after being left at 40° C. for one month, and remained stable without forming any aggregates. A paint was prepared by adding 37 parts by weight of HM-100 and 10 parts by weight of butyl cellosolve to 194 parts by weight of this aqueous polymer dispersion, diluted with water and heated in a #4 food cup for 30 seconds, resulting in a solid content of 32 parts by weight.
%, and the amount of organic lactic agent in volatile substances was 11%. This was painted on an iron plate and baked at 140°C for 30 minutes. Example
6 Hydroxypropyl acrylate 60 parts by weight Acrylic acid 5 parts by weight Methyl methacrylate 35 parts by weight Azobisisobutyronitrile 1 part by weight was dropped into 100 parts by weight of cellosolve heated to 120°C, and polymerization was carried out over 7 hours. After this, 2 parts by weight of glycidyl methacrylate, 0.05 parts by weight of hydroquinone, and 0.5 parts by weight of dimethylaminoethanol were added, and heating was continued for a further 6 hours.

この酪液から溶剤７０重量部を留去させトリエチルアミ
ンで当量中和した後、水で希釈し８％の水溶液とした。
この水醇液１００重量部に、スチレン
４０重量部アクリル酸エチル ２８
重量部Ｎ−メチロールアクリルアミド ５重量部ｎ−
ドデシルメルカプタン ０．１重量部を加えて１時
間撹拌した後、過硫酸アンモニウム１重量部を水１０重
量部に溶かして加えて７５℃で４時間加熱したところ固
形分４４％で粘度８５センチポイズの重合体水性分散液
が得りれた。70 parts by weight of the solvent was distilled off from this milky liquor, neutralized by equivalent amount with triethylamine, and then diluted with water to obtain an 8% aqueous solution.
Styrene was added to 100 parts by weight of this aqueous solution.
40 parts by weight ethyl acrylate 28
Parts by weight N-Methylol acrylamide 5 parts by weight n-
After adding 0.1 part by weight of dodecyl mercaptan and stirring for 1 hour, 1 part by weight of ammonium persulfate dissolved in 10 parts by weight of water was added and heated at 75°C for 4 hours, resulting in a polymer with a solid content of 44% and a viscosity of 85 centipoise. An aqueous dispersion was obtained.

この分散液は４０℃で１力月間放置しても粘度の変化が
なく、凝集物もできず安定であつた。この重合体水性分
散液１５９重量部にＨＭ−１００を３７重量部、ブチル
セロソルブ１０重量部加えて塗料を作製し、水で希釈し
てフオードカツプ＃４で３０秒にしたところ固形分３６
％、揮発性物質中の有機溶剤量９％であつた。これを鉄
板に塗装し、１４０℃で３０分間焼付けた。この分散液
は４００Ｃで１力月間放置しても粘度の変化がなく、凝
集物もできず安定であつた。比較例 １ 実施例１の乳化重合せしめる単量体混合物におけるＮ−
ブトキシメチルアクリルアミドをアクリル酸ブチルに、
さらにＮ−メチロールメタクリルアミドを２−ヒドロキ
シエチルメタクリレートに代えた以外は実施例１に記載
したのと同様にして乳化重合を行なつたところ、固形分
４５％の安定な重合体水性分散液が得られた。This dispersion did not change in viscosity even after being left at 40° C. for one month, and remained stable without forming any aggregates. A paint was prepared by adding 37 parts by weight of HM-100 and 10 parts by weight of butyl cellosolve to 159 parts by weight of this aqueous polymer dispersion, diluted with water and heated in a #4 food cup for 30 seconds, resulting in a solid content of 36.
%, and the amount of organic solvent in volatile substances was 9%. This was painted on an iron plate and baked at 140°C for 30 minutes. This dispersion remained stable even after being left at 400C for one month without any change in viscosity or formation of aggregates. Comparative Example 1 N- in the monomer mixture for emulsion polymerization of Example 1
butoxymethylacrylamide to butyl acrylate,
Furthermore, emulsion polymerization was carried out in the same manner as described in Example 1 except that N-methylolmethacrylamide was replaced with 2-hydroxyethylmethacrylate, and a stable aqueous polymer dispersion with a solid content of 45% was obtained. It was done.

該水性分散液１６３重量部に、ＨＭ−１００を３７重量
部およびブチルセロソルブ１０重量部を加えて作成した
塗料を、水で希釈してフオードカツプ＃４で３０秒にし
たところ、固形分３４％、揮発性物質中の有機溶剤量１
１％であつた。これを鉄板にスプレー塗装し、１４０℃
で３０分焼付けた。比較例 ２ ドデシルベンゼンスルホン酸ソーダ（界面活性剤）２重
量部および過硫酸アンモニウム０．７重量部を含む水洛
液９２重量部に、実施例１における重合体水性分散液の
乳化剤および分散粒子の全体を構成するモノマー成分、
すなわち、ヒドロキシエチルメタクリレート３．７５重
量部、アクリル酸３重量部、スチレン６重量部、メタク
リル酸エチル５、２５重量部、メタクリル酸メチル２４
重量部、アクリル酸エチル１５重量部、Ｎ−ブトキシメ
チルアクリルアミド１５重量部、Ｎ−メチロールメタク
リルアミド３重量部を滴下し、８０℃において乳化重合
を行なつたところ、固形分４５％の水性分散液が得られ
た。A paint prepared by adding 37 parts by weight of HM-100 and 10 parts by weight of butyl cellosolve to 163 parts by weight of the aqueous dispersion was diluted with water and heated in a #4 food cup for 30 seconds, resulting in a solid content of 34% and volatile content. Amount of organic solvent in the chemical substance1
It was 1%. Spray paint this on a steel plate and heat it to 140℃.
Bake for 30 minutes. Comparative Example 2 To 92 parts by weight of an aqueous solution containing 2 parts by weight of sodium dodecylbenzenesulfonate (surfactant) and 0.7 parts by weight of ammonium persulfate, the emulsifier and the entire dispersed particles of the aqueous polymer dispersion in Example 1 were added. Monomer components constituting the
That is, 3.75 parts by weight of hydroxyethyl methacrylate, 3 parts by weight of acrylic acid, 6 parts by weight of styrene, 5.25 parts by weight of ethyl methacrylate, 24 parts by weight of methyl methacrylate.
parts by weight, 15 parts by weight of ethyl acrylate, 15 parts by weight of N-butoxymethylacrylamide, and 3 parts by weight of N-methylolmethacrylamide were added dropwise and emulsion polymerization was carried out at 80°C, resulting in an aqueous dispersion with a solid content of 45%. was gotten.

この水性分散液１５６重量部に、トリエチルアミンを加
えて当量中和し、さらにセロソルブを２０重量部および
ＨＭ−１００を３７重量部を加えて作成した塗料を水で
希釈してフオードカツプ＃４で３０秒にしたところ、固
形分４４％、揮発性物質中の有機醇剤量２４％であつた
。これを鉄板にスプレー塗装し、１４０℃で３０分間焼
付けた。比較例 ３ 実施例１の重合体水性分散液の乳化剤および分散粒子の
全体を構成するモノマー成分、すなわち、ヒドロキシエ
チルメタクリレート３．７５重量部、アクリル酸３重量
部、スチレン６重量部、メタクリル酸エチル５．２５重
量部、メタクリル酸メチル２４重量部、アクリル酸エチ
ル１５重量部、Ｎブトキシメチルアクリルアミド１５重
量部、Ｎーメチロールメタクリルアミド３重量部および
アゾビスイソブチロニトリル０．７５重量部を、１２０
℃に加熱したセロソルブ７５重量部に滴下し、７時間重
合を行なつた後、有機醗剤３５重量部を留去し、トリエ
チルアミンで中和し、水を加えて２０％水酪液とした。To 156 parts by weight of this aqueous dispersion, an equivalent amount of triethylamine was added to neutralize it, and 20 parts by weight of Cellosolve and 37 parts by weight of HM-100 were added to make a paint. The paint was diluted with water and heated in a #4 food cup for 30 seconds. As a result, the solid content was 44%, and the amount of organic liqueur in volatile substances was 24%. This was spray-painted on an iron plate and baked at 140°C for 30 minutes. Comparative Example 3 Monomer components constituting the entire emulsifier and dispersed particles of the aqueous polymer dispersion of Example 1, namely, 3.75 parts by weight of hydroxyethyl methacrylate, 3 parts by weight of acrylic acid, 6 parts by weight of styrene, and ethyl methacrylate. 5.25 parts by weight, 24 parts by weight of methyl methacrylate, 15 parts by weight of ethyl acrylate, 15 parts by weight of N-butoxymethylacrylamide, 3 parts by weight of N-methylolmethacrylamide, and 0.75 parts by weight of azobisisobutyronitrile, 120
The mixture was added dropwise to 75 parts by weight of cellosolve heated to 0.degree. C., and after polymerization for 7 hours, 35 parts by weight of the organic thickener was distilled off, neutralized with triethylamine, and water was added to obtain a 20% aqueous solution.

該水浩液３５０重量部ＨＭ一１００を３７重量部配合し
たのち、水で希釈してフオードカツプ＃４で３０秒にし
たところ固形分は２０％で、揮発性物質中の有機爵剤は
１２％であつた。これを鉄板にスプレー塗装し、１４０
℃で３０分間焼付けた。比較例 ４ 実施例１における乳化重合せしめる単量体混合物の組成
を以下のごとくに代えた他は実施例１と同様にして塗料
を作成した。After blending 350 parts by weight of the water solution with 37 parts by weight of HM-100, it was diluted with water and heated in a #4 food cup for 30 seconds, and the solid content was 20%, and the organic additive in the volatile substances was 12%. It was hot. Spray paint this on the iron plate, 140
Baked at ℃ for 30 minutes. Comparative Example 4 A coating material was prepared in the same manner as in Example 1 except that the composition of the monomer mixture to be subjected to emulsion polymerization in Example 1 was changed as follows.

フオードカツプ＃４で３０秒における固形分は３４％で
、揮発性物質中に含まれる有機溶剤は１１％であつた。
これを鉄板にスプレーで塗装し、１４０℃で３０分間焼
付けた。メタクリル酸メチル ３２重量部
アクリル酸エチル ２３重量部Ｎ−ブト
キシメチルアクリルアミド １．５重量部Ｎ−メチロー
ルメタクリルアミド ０．５重量部ヒドロキシエチルメ
タクリレート ３重量部比較例 ５実施例１における
乳化重合せしめる単量体混合物の組成を以下のごとくに
代えた他は実施例１と同様にして塗料を作成した。The solids content at 30 seconds in food cup #4 was 34%, and the organic solvent contained in the volatiles was 11%.
This was spray painted on an iron plate and baked at 140°C for 30 minutes. Methyl methacrylate 32 parts by weight Ethyl acrylate 23 parts by weight N-butoxymethylacrylamide 1.5 parts by weight N-methylolmethacrylamide 0.5 parts by weight Hydroxyethyl methacrylate 3 parts by weight Comparative Example 5 Monomers for emulsion polymerization in Example 1 A paint was prepared in the same manner as in Example 1, except that the composition of the body mixture was changed as follows.

フオードカツプ＃４で３０秒における固形分は３４％で
、揮発性物質中に含まれる有機溶剤は１１％であつた。
これを鉄板にスプレーで塗装し、１４０℃で３０分間焼
付けた。メタクリル酸 １５重量部
アクリル酸エチル １０重量部Ｎ−ブト
キシメチルアクリルアミド ２７重量部Ｎ−メチロール
メタクリルアミド ５重量部ヒドロキシエチルメタク
リレート ３重量部性能試験結果上記実施例および比
較例で得た水で希釈後の組成物の性状および焼付けた塗
膜の性能試験結果を次表に示した。The solids content at 30 seconds in food cup #4 was 34%, and the organic solvent contained in the volatiles was 11%.
This was spray painted on an iron plate and baked at 140°C for 30 minutes. Methacrylic acid 15 parts by weight Ethyl acrylate 10 parts by weight N-butoxymethylacrylamide 27 parts by weight N-methylolmethacrylamide 5 parts by weight Hydroxyethyl methacrylate 3 parts by weight Performance test results After dilution with water obtained in the above examples and comparative examples The properties of the composition and the performance test results of the baked coating are shown in the table below.

Claims (1)

【特許請求の範囲】 １ （Ａ）アクリル酸ヒドロキシアルキルおよび／また
はメタクリル酸ヒドロキシアルキル５〜６０重量％、ア
クリル酸および／またはメタクリル酸５〜２０重量％、
およびアクリル酸アルキルエステル、メタクリル酸アル
キルエステルおよびスチレンから選ばれる少くとも１種
の共重合可能なモノエチレン系不飽和単量体２０〜９０
重量％を共重合せしめ中和して得られる水溶性共重合体
を乳化剤として、次の一般式▲数式、化学式、表等があ
ります▼ （式中Ｒは水素原子またはメチル基、Ｒ′は水素原子、
またはＣ＿ｎＨ＿２＿ｎ＿＋＿１でｎは１〜４の数字を
示す。 ）で表わされる化合物５〜５０重量％、およびビニル単
量体５０〜９５重量％からなる単量体混合物を乳化重合
せしめた重合体水性分散液と、（Ｂ）アミノ樹脂とより
なり、かつ（Ａ）および（Ｂ）の配合割合が固形分換算
重量比で（Ａ）／（Ｂ）＝９５／５〜６０／４０であつ
て、それに含有される揮発性物質中の有機溶剤の含有量
が３〜３０重量％であることを特徴とする熱硬化性被覆
組成物。[Scope of Claims] 1 (A) 5 to 60% by weight of hydroxyalkyl acrylate and/or hydroxyalkyl methacrylate, 5 to 20% by weight of acrylic acid and/or methacrylic acid,
and at least one copolymerizable monoethylenically unsaturated monomer selected from acrylic acid alkyl ester, methacrylic acid alkyl ester, and styrene 20 to 90
The water-soluble copolymer obtained by copolymerizing and neutralizing % by weight is used as an emulsifier, and the following general formula ▲ Numerical formula, chemical formula, table, etc. ▼ (In the formula, R is a hydrogen atom or a methyl group, R' is hydrogen atom,
Or C_nH_2_n_+_1, where n represents a number from 1 to 4. ); and (B) an amino resin; and (B) an amino resin. The blending ratio of A) and (B) is (A)/(B) = 95/5 to 60/40 in terms of solid content weight ratio, and the content of organic solvent in the volatile substances contained therein is A thermosetting coating composition characterized in that it contains 3 to 30% by weight.