JP2004359748A - Heat-resistant resin composition and coating material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat-resistant resin composition which, when formed into a coating film, does not lower its adhesiveness to a stainless steel sheet even at a high temperature, can decrease the content of an organic solvent, does not cause environmental pollution and work environment worsening, and is advantageous from the viewpoint of safety and hygiene; and a coating material containing the composition as a coating film component. <P>SOLUTION: The heat-resistant resin composition is prepared by compounding (A) a polyamideimide resin prepared by reacting a diisocyanate compound or a diamine compound with a tribasic acid anhydride or a tribasic acid anhydride chloride in a basic polar solvent with (B) a basic compound, (C) water, and (D) chromium acetylacetonate. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

［式中、Ｒ^１は３価の有機基を表し、 Ｒ^２は２価の有機基を表し、ｎは整数を表す。］
Ｒ^１としては、芳香環を有する炭素数６〜２０の３価の有機基が好ましく、Ｒ^２としては、芳香環を有する炭素数６〜２０の２価の有機基が好ましい。ｎは繰り返し構造単位（Ｉ）の数であり、Ｒ^１及びＲ^２の構造によって異なるが、一般的に１０〜２００とするのが好ましい。
このようなポリアミドイミド樹脂は、塩基性極性溶媒中でジイソシアネート化合物又はジアミン化合物と三塩基酸無水物又は三塩基酸無水物クロライドとを反応させて得ることができる。塩基性極性溶媒としては、Ｎ−メチル−２−ピロリドン等の高沸点溶媒を用いるのが好ましい。また、使用量に特に制限はないが、ジイソシアネート化合物又はジアミン化合物と三塩基酸無水物の総量１００重量％に対して１００〜５００重量％とするのが好ましい。反応温度は、通常、８０〜１８０℃である。
【００１６】
ジイソシアネート化合物又はジアミン化合物と三塩基酸無水物又は三塩基酸無水物クロライドは、それぞれ芳香族化合物を使用することが好ましい。上記製造法に用いられる代表的な化合物を次に列挙する。
まず、ジイソシアネート化合物としては、４，４′−ジフェニルメタンジイソシアネート、キシリレンジイソシアネート、３，３′−ジフェニルメタンジイソシアネート、パラフェニレンジイソシアネート等が挙げられる。
また、ジアミンとしては、４，４′−ジアミノジフェニルエーテル、４，４′−ジアミノジフェニルスルホン、３，３′−ジアミノジフェニルスルホン、キシリレンジアミン、フェニレンジアミン等が挙げられる。
【００１７】
また、三塩基酸無水物としては、トリメリット酸無水物等が挙げられ、三塩基酸無水物クロライドとしては、トリメリット酸無水物クロライド等が挙げられる。
ポリアミドイミド樹脂を合成する際に、ジカルボン酸、テトラカルボン酸二無水物等をポリアミドイミド樹脂の特性を損なわない範囲で同時に反応させることができる。
ジカルボン酸としては、テレフタル酸、イソフタル酸、アジピン酸等が挙げられ、テトラカルボン酸二無水物としては、ピロメリット酸二無水物、ベンゾフェノンテトラカルボン酸二無水物、ビフェニルテトラカルボン酸二無水物等が挙げられる。
【００１８】
前記ジイソシアネート化合物又はジアミン化合物と三塩基酸無水物又は三塩基酸無水物クロライドと必要に応じて使用するジカルボン酸及びテトラカルボン酸二無水物の使用量は、生成されるポリアミドイミド樹脂の分子量、架橋度の観点から酸成分の総量１．０モルに対してジイソシアネート化合物又はジアミン化合物を０．８〜１．１モルとすることが好ましく、０．９５〜１．０８モルとすることがより好ましく、特に、１．０〜１．０８モル使用されることが好ましい。また、酸成分中、ジカルボン酸及びテトラカルボン酸二無水物は、これらの総量が０〜５０モル％の範囲で使用されるのが好ましい。
【００１９】
なお、ポリアミドイミド樹脂の数平均分子量は、樹脂合成時にサンプリングしてゲルパーミエーションクロマトグラフ（ＧＰＣ）により、標準ポリスチレンの検量線を用いて測定し、目的の数平均分子量になるまで合成を継続することにより上記範囲に管理される。
【００２０】
本発明に用いられるポリアミドイミド樹脂は、数平均分子量が５，０００〜５０，０００のものが好ましい。数平均分子量が５，０００未満では、塗膜としたときの、塗膜の耐熱性や機械的特性等の諸特性が低下する傾向があり、５０，０００を超えると、塗料として適正な濃度で溶媒に溶解したときに粘度が高くなり、塗装時の作業性に劣る傾向がある。このことから、数平均分子量は１０，０００〜３０，０００とすることが好ましく、１５，０００〜２５，０００とすることが特に好ましい。
【００２１】
また、カルボキシル基及び酸無水物基を開環させたカルボキシル基を合わせた酸価が１０〜１００であることが好ましく、１０未満であると塩基性化合物と反応するカルボキシル基が不足するため、水溶化が困難となり、１００を超えると最終的に得られる耐熱性樹脂組成物が経日にてゲル化しやすくなる。このことから、カルボキシル基及び酸無水物基を開環させたカルボキシル基を合わせた酸価が２０〜８０とすることがより好ましく、３０〜６０とすることが特に好ましい。
【００２２】
なお、ポリアミドイミド樹脂のカルボキシル基及び酸無水物基を開環させたカルボキシル基を合わせた酸価は、以下の方法で得ることができる。ます、ポリアミドイミド樹脂を約０．５ｇとり、これに１，４−ジアザビシクロ［２，２，２］オクタンを約０．１５ｇ加え、さらにＮ−メチル−２−ピロリドンを約６０ｇ及びイオン交換水を約１ｍｌ加え、ポリアミドイミド樹脂が完全に溶解するまで攪拌する。これを０．０５モル／ｌエタノール性水酸化カリウム溶液を使用して電位差滴定装置で滴定し、ポリアミドイミド樹脂のカルボキシル基及び酸無水物基を開環させたカルボキシル基を合わせた酸価を得る。
【００２３】
本発明において、塩基性化合物としてはトリエチルアミン、トリブチルアミン、トリエチレンジアミン、Ｎ−メチルモルフォリン等のアルキルアミン、メチルアニリン、ジメチルアニリン等のアルキルアニリン、モノエタノールアミン、ジエタノールアミン、トリエタノールアミン、ジプロパノールアミン、トリプロパノールアミン、Ｎ−エチルエタノールアミン、Ｎ，Ｎ−ジメチルエタノールアミン、シクロヘキサノールアミン、Ｎ−メチルシクロヘキサノールアミン、Ｎ−ベンジルエタノールアミン等のアルカノールアミン類が適しているが、これら以外の塩基性化合物、例えば水酸化ナトリウムや水酸化カリウム等の苛性アルカリ又はアンモニア水等を使用してもよく特に制限はない。好ましくは、トリエチルアミン、Ｎ−メチルモルフォリン、トリエチレンジアミン、Ｎ，Ｎ−ジメチルエタノールアミンが使用される。
【００２４】
塩基性化合物は、上記の有機溶媒中で反応させて得られるポリアミドイミド樹脂中に含まれるカルボキシル基及び開環させた酸無水物基を合わせた酸価に対して、１〜２０当量用いられる。１当量未満では樹脂の水溶化が困難となり、２０当量を越えると樹脂の加水分解が促進され、長期の保存により粘度又は特性低下をきたすことがある。このことから、カルボキシル基及び酸無水物基を開環させたカルボキシル基を合わせた酸価に対して、２〜１０当量とすることが好ましく、３〜８当量とすることが特に好ましい。
【００２５】
塩基性化合物はポリアミドイミド樹脂の末端にあるカルボキシル基と塩を形成して親水性基となる。塩形成に際しては水の共存下に行ってもよいし、塩基性化合物を添加した後、水を加えてもよい。塩を形成させる温度は０℃〜２００℃、好ましくは４０℃〜１３０℃の範囲で行われる。
【００２６】
塩基性化合物の種類と量及び水の添加方法によって、得られる水性樹脂組成物の形態はエマルジョン状、半透明溶液、透明溶液等となるが、貯蔵安定性、塗装作業性の点から、半透明あるいは透明溶液にすることが好ましい。
水としてはイオン交換水が好ましく用いられ、（Ａ）成分、（Ｂ）成分、（Ｃ）成分の合計量に対して好ましくは５〜９９重量％、より好ましくは２０〜６０重量％配合される。この配合量が５重量％未満では含有する水が少ないことから一般に水溶性ポリマーとして称されず、９９重量％を超えると塗料として機能しなくなる傾向がある。
【００２７】
クロムアセチルアセトナートの配合量は、ポリアミドイミド樹脂１００重量％に対し、０．０１〜２０重量％の範囲とされる。０．０１重量％未満となると、密着性向上効果が小さくなり、２０重量％を超えると塗膜の耐熱性が漸次低下する傾向を示す。このことから、クロムアセチルアセトナートの配合量は、ポリアミドイミド樹脂１００重量％に対し、０．０５〜１０重量％とすることが好ましく、０．１〜８重量％とすることがより好ましい。クロムアセチルアセトナートは、塩基性極性溶媒に溶解した溶液としてポリアミドイミド樹脂と混合することができる。塩基性極性溶媒としては、Ｎ‐メチル‐２‐ピロリドン、Ｎ，Ｎ‐ジメチルホルムアミドなどを用いることができる。溶液の濃度については、特に制限はないが、例えば、クロムアセチルアセトナート１００重量％を塩基性極性溶媒９００〜４０００重量％に溶解される。クロムアセチルアセトナートの配合方法についてはこれに限られるものではなく、他の適宜の方法によってもよい。
【００２８】
このようにして得られた耐熱性樹脂組成物は使用する際に必要に応じて適当な濃度に希釈される。希釈溶媒としては、水、ジメチルホルムアミド、ジメチルアセトアミド、ジメチルスルフォキシド、Ｎ−メチル−２−ピロリドン等の極性溶媒の他に、助溶媒として、ポリオール類、これらの低級アルキルエーテル化物、アセチル化物等を用いてもよい。例えば、エチレングリコール、ジエチレングリコール、トリエチレングリコール、テトラエチレングリコール、グリセリン、トリメチロールプロパン、イソプロピルアルコール、又はそれらのモノメチルエーテル化物、モノエチルエーテル、モノイソプロピルエーテル化物、モノブチルエーテル化物、ジメチルエーテル化物及びこれらのモノアセチル化物等が使用される。
【００２９】
本発明による耐熱性樹脂組成物は、被塗物に塗布、硬化させて、被塗物表面に塗膜を形成する。ステンレス鋼板を被塗物としたとき、特に著しい効果を挙げることができる。
【００３０】
【実施例】
次に本発明の実施例について説明するが、本発明はこれらの実施例に限定されない。
【００３１】
実施例１
無水トリメリット酸１１０６．２ｇ、４，４−ジフェニルメタンジイソシアネート１４５５．８ｇ、Ｎ−メチル−２−ピロリドン２５６２．０ｇを温度計、攪拌機、冷却管を備えたフラスコに入れ、乾燥させた窒素気流中で攪拌しながら約２時間かけて徐々に昇温して１３０℃まで上げた。反応により生ずる炭酸ガスの急激な発泡に注意しながら１３０℃を保持し、このまま約６時間加熱を続けた後反応を停止させ、ポリアミドイミド樹脂溶液を得た。
【００３２】
このポリアミドイミド樹脂溶液の不揮発分（２００℃−２ｈ）は約５０重量％で、粘度（３０℃）は約８５．０Ｐａ・ｓであった。また、ポリアミドイミド樹脂の数平均分子量は約１７，０００で、カルボキシル基及び酸無水物基を開環させたカルボキシル基を合わせた酸価は約４０であった。なお、数平均分子量は次の条件にて測定した。
機種：日立製作所製 Ｌ６０００（商品名）
検出器：日立製作所製 Ｌ４０００型ＵＶ（商品名）
波長：２７０ｎｍ
データ処理機：ＡＴＴ ８
カラム：Ｇｅｌｐａｃｋ ＧＬ−Ｓ３００ＭＤＴ−５×２
カラムサイズ：８ｍｍφ×３００ｍｍ
溶媒：ＤＭＦ／ＴＨＦ＝１／１（リットル）＋リン酸０．０６Ｍ＋臭化リチウム０．０６Ｍ
試料濃度：５ｍｇ／１ｍｌ
注入量：５μｌ
圧力：４９ｋｇｆ／ｃｍ^２（４．８×１０^６Ｐａ）
流量：１．０ｍｌ／ｍｉｎ
【００３３】
このポリアミドイミド樹脂溶液２，７００ｇを温度計、攪拌機、冷却管を備えたフラスコに入れ、乾燥させた窒素気流中で攪拌しながら徐々に昇温して５０℃まで上げた。５０℃に達したところでトリエチルアミンを４４７．１ｇ（４当量）添加し、５０℃に保ちながら十分に攪拌した後、攪拌しながら徐々にイオン交換水を加えた。最終的にイオン交換水が１３４８．８ｇ（３０重量％）となるまで加えて、透明で均一な耐熱性樹脂組成物を得た。
上記方法で作製された耐熱性樹脂組成物１００重量％（不揮発分３０重量％）にクロムアセチルアセトナートのＮ‐メチル‐２‐ピロリドン溶液（不揮発分１０重量％）１．７重量％を配合し、耐熱性樹脂組成物を得た。
【００３４】
実施例２
無水トリメリット酸３８２．９ｇ、４，４′−ジフェニルメタンジイソシアネート５０３．９ｇ、Ｎ−メチル−２−ピロリドン８８６．８ｇを温度計、攪拌機、冷却管を備えたフラスコに入れ、乾燥させた窒素気流中で攪拌しながら約１時間かけて徐々に昇温して８０℃まで上げた。反応により生ずる炭酸ガスの急激な発泡に注意しながら８０℃を保ち、加熱開始から約７時間加熱を続けた後反応を停止させ、ポリアミドイミド樹脂溶液を得た。
このポリアミドイミド樹脂溶液の不揮発分（２００℃−２ｈ）は約５０重量％で、粘度（３０℃）は約８０．０Ｐａ・ｓであった。また、ポリアミドイミド樹脂の数平均分子量は約１５，０００で、カルボキシル基及び酸無水物基を開環させたカルボキシル基を合わせた酸価は約５０であった。
このポリアミドイミド樹脂溶液２００ｇを温度計、攪拌機、冷却管を備えたフラスコに入れ、乾燥させた窒素気流中で攪拌しながら徐々に昇温して９０℃まで上げた。９０℃に達したところでＮ−メチルモルホリンを７０．８ｇ（８当量）添加し、９０℃に保ちながら十分に攪拌した後、攪拌しながら徐々にイオン交換水を加えた。最終的にイオン交換水が１８０．５ｇ（４０重量％）となるまで加えて、透明で均一な耐熱性樹脂組成物を得た。
上記方法で作製された耐熱性樹脂組成物１００重量％（不揮発分２２重量％）にクロムアセチルアセトナートのＮ‐メチル‐２‐ピロリドン溶液（不揮発分５重量％）４．４重量％を配合し、耐熱性樹脂組成物を得た。
【００３５】
実施例３
無水トリメリット酸２３３．８ｇ、無水ベンゾフェノンテトラカルボン酸９８．０ｇ、４，４′−ジフェニルメタンジイソシアネート３８４．６ｇ、Ｎ−メチル−２−ピロリドン１６７１．６ｇを温度計、攪拌機、冷却管を備えたフラスコに入れ、乾燥させた窒素気流中で攪拌しながら約１時間かけて徐々に昇温して１２０℃まで上げた。反応により生ずる炭酸ガスの急激な発泡に注意しながら徐々に昇温して１５０℃まで上げ、加熱開始から５時間加熱を続けた後反応を停止させ、ポリアミドイミド樹脂溶液を得た。
このポリアミドイミド樹脂溶液の不揮発分（２００℃−２ｈ）は約３０重量％で、粘度（３０℃）は約２．１Ｐａ・ｓであった。また、ポリアミドイミド樹脂の数平均分子量は約２３，０００で、カルボキシル基及び酸無水物基を合わせた酸価は約３０であった。
このポリアミドイミド樹脂溶液２００ｇを温度計、攪拌機、冷却管を備えたフラスコに入れ、乾燥させた窒素気流中で攪拌しながら徐々に昇温して１１０℃まで上げた。１１０℃に達したところでＮ，Ｎ−ジメチルエタノールアミンを１７．６ｇ（６当量）添加し、１１０℃に保ちながら十分に攪拌した後、攪拌しながら徐々にイオン交換水を加えた。最終的にイオン交換水が２１７．６ｇ（５０重量％）となるまで加えて、透明で均一な耐熱性樹脂組成物を得た。
上記方法で作製された耐熱性樹脂組成物１００重量％（不揮発分１４重量％）にクロムアセチルアセトナートのＮ‐メチル‐２‐ピロリドン溶液（不揮発分１０重量％）７．０重量％を配合し、耐熱性樹脂組成物を得た。
【００３６】
比較例１
無水トリメリット酸８７６．９ｇ、４，４′−ジフェニルメタンジイソシアネート１１５３．８ｇ、Ｎ−メチル−２−ピロリドン４，７３８．３ｇを温度計、攪拌機、冷却管を備えたフラスコに入れ、乾燥させた窒素気流中で攪拌しながら約１時間かけて徐々に昇温して１１０℃まで上げた。反応により生ずる炭酸ガスの急激な発泡に注意しながら徐々に昇温して１２０℃まで上げた。加熱開始から約８時間加熱を続けた後反応を停止させ、ポリアミドイミド樹脂溶液を得た。
このポリアミドイミド樹脂溶液の不揮発分（２００℃−２ｈ）は約３０重量％で、粘度（３０℃）は約１．８Ｐａ・ｓであった。また、ポリアミドイミド樹脂の数平均分子量は約２１，０００で、カルボキシル基及び酸無水物基を開環させたカルボキシル基を合わせた酸価は約３５であった。
【００３７】
実施例１、２及び３、及び比較例１で得られた塗料をステンレス鋼板（ＳＵＳ４３０）に塗布した後、３００℃で３０分間焼付けて膜厚１０μｍの塗膜板を形成した。塗膜を形成したステンレス鋼板について、初期及び３００℃に所定の時間さらした後の密着性を旧ＪＩＳ Ｋ５４００に準じて測定した（％、クロスカット残率）。その結果を表１に示す。
【００３８】
【表１】

【００３９】
比較例１の初期において、密着性の数値に幅があるのは初期密着性にロット間のばらつきがあるためであり、実施例１、２及び３の数値に幅がないのはロット間のばらつきがないことを示す。
表１から、実施例１、２及び３で得られた塗料は、比較例の塗料と比較して、有機溶剤含有量が低減され、かつ、実施例１、２及び３で得られた塗料から得られた塗膜は、比較例の塗料から得られた塗膜と比較して、初期及び３００℃劣化後の密着性が著しく優れていることがわかる。
【００４０】
【発明の効果】
本発明の耐熱性樹脂組成物は、塗膜としたとき、高温にさらされてもステンレス鋼板に対して密着性が低下せず、かつ有機溶剤含有量を低減させていることより、各種の耐熱塗料用途の中でも特に高耐熱用途に有用であり、かつ環境汚染や作業環境の悪化がなく、安全衛生面に対して有利であることから、工業的に多大な有効性を有するものである。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a heat-resistant resin composition and a paint.
[0002]
[Prior art]
It is well known that a polyamideimide resin has excellent heat resistance, chemical resistance, and mechanical properties, and is widely used as a heat-resistant wire coating, a metal surface protection coating, and the like. A general method for producing a polyamideimide resin in an organic solvent type resin solution is known. (For example, see Patent Document 1)
[0003]
In the field of heat-resistant protective coatings used for automobile parts, cooking utensils, etc., it is required not only to have excellent heat resistance, but also to maintain the adhesion even when exposed to high temperatures. However, although the heat-resistant protective coating using a polyamideimide resin as a coating component has excellent heat resistance, the adhesiveness is reduced when exposed to high temperatures, and the tendency is particularly remarkable when the object to be coated is a stainless steel plate. Yes, if this problem can be solved, further expansion can be expected.
[0004]
On the other hand, aqueous resin solutions that use water as a medium instead of organic solvents have attracted attention in terms of environmental protection, health and safety, economics, and workability in painting. A method of solubilizing a polyamideimide resin to be made to act is reported (for example, see Patent Documents 2 and 3). However, it has been difficult to achieve stable production by the conventional method, and has not been put to practical use until now.
[Patent Document 1] Japanese Patent Publication No. 44-19274 [Patent Document 2] Japanese Patent Publication No. 60-6667
[Patent Document 3] Japanese Patent Publication No. 60-6366
[Problems to be solved by the invention]
The present invention, when formed into a coating film, does not decrease its adhesion to stainless steel plates even when exposed to high temperatures, and reduces the content of organic solvents, without environmental pollution and deterioration of the working environment, and is safe and hygienic. It is an object of the present invention to provide a heat-resistant resin composition which is advantageous to the above and a coating material comprising the same as a coating film component.
[0007]
[Means for Solving the Problems]
As a result of examining the adhesion to the stainless steel plate when exposed to the above-mentioned high temperature, a polyamideimide resin obtained by reacting a diisocyanate compound or a diamine compound with a tribasic anhydride or tribasic anhydride chloride and a basic By adding chromium acetylacetonate to the heat-resistant resin composition obtained by the compound, the decrease in adhesion to the stainless steel sheet after being exposed to high temperatures is improved, and the reduction in organic solvents can contribute to the environment. This led to the present invention. That is, the present invention relates to (A) a polyamideimide resin obtained by reacting a diisocyanate compound or a diamine compound with a tribasic anhydride or a tribasic anhydride chloride in a basic polar solvent, and (B) a basic compound. , (C) water and (D) chromium acetylacetonate.
[0008]
Further, in the present invention, the basic compound of the component (B) combines the carboxyl group contained in the polyamideimide resin of the component (A) and the carboxyl group obtained by ring-opening the acid anhydride group in the polyamideimide resin. The present invention relates to a heat-resistant resin composition which is blended in an amount of 1 to 20 equivalents with respect to the acid value.
[0009]
Further, the present invention provides a heat-resistant resin composition wherein the water of the component (C) is blended in an amount of 5 to 99% by weight based on the total amount of the components (A), (B) and (C). About.
[0010]
Further, in the present invention, the polyamideimide resin has a number average molecular weight of 5,000 to 50,000, and an acid value of a carboxyl group obtained by ring-opening a carboxyl group and an acid anhydride group of 10 to 100. And a heat-resistant resin composition.
[0011]
The present invention also relates to a heat-resistant resin composition in which the basic compound (B) is an alkylamine or an alkanolamine.
[0012]
The present invention also relates to a heat-resistant resin composition in which the chromium acetylacetonate (D) is incorporated in an amount of 0.01 to 20% by weight based on 100% by weight of the heat-resistant resin composition.
[0013]
Further, the present invention relates to a paint comprising the above-mentioned heat-resistant resin composition as a coating film component.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
The polyamideimide resin used in the present invention preferably has a repeating structural unit represented by the general formula (I), but is not limited thereto.
[0015]
Embedded image

[Wherein, R ¹ represents a trivalent organic group, R ² represents a divalent organic group, and n represents an integer. ]
R ¹ is preferably a trivalent organic group having 6 to 20 carbon atoms having an aromatic ring, and R ² is preferably a divalent organic group having 6 to 20 carbon atoms having an aromatic ring. n is the number of the repeating structural units (I) and varies depending on the structures of R ¹ and R ² , but is generally preferably from 10 to 200.
Such a polyamideimide resin can be obtained by reacting a diisocyanate compound or a diamine compound with a tribasic acid anhydride or tribasic acid anhydride chloride in a basic polar solvent. As the basic polar solvent, it is preferable to use a high boiling point solvent such as N-methyl-2-pyrrolidone. The amount used is not particularly limited, but is preferably 100 to 500% by weight based on 100% by weight of the total amount of the diisocyanate compound or the diamine compound and the tribasic anhydride. The reaction temperature is usually from 80 to 180 ° C.
[0016]
As the diisocyanate compound or the diamine compound and the tribasic acid anhydride or the tribasic acid anhydride chloride, it is preferable to use an aromatic compound. Representative compounds used in the above production method are listed below.
First, examples of the diisocyanate compound include 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, 3,3'-diphenylmethane diisocyanate, and paraphenylene diisocyanate.
Examples of the diamine include 4,4'-diaminodiphenylether, 4,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, xylylenediamine, and phenylenediamine.
[0017]
Further, examples of the tribasic acid anhydride include trimellitic anhydride, and examples of the tribasic anhydride chloride include trimellitic anhydride chloride.
When synthesizing the polyamideimide resin, dicarboxylic acid, tetracarboxylic dianhydride and the like can be simultaneously reacted within a range that does not impair the properties of the polyamideimide resin.
Examples of the dicarboxylic acid include terephthalic acid, isophthalic acid, and adipic acid, and examples of the tetracarboxylic dianhydride include pyromellitic dianhydride, benzophenone tetracarboxylic dianhydride, and biphenyltetracarboxylic dianhydride. Is mentioned.
[0018]
The diisocyanate compound or diamine compound and tribasic acid anhydride or tribasic acid anhydride chloride and the amount of dicarboxylic acid and tetracarboxylic dianhydride used as necessary are determined according to the molecular weight of the polyamide-imide resin to be produced, and From the viewpoint of the degree, the diisocyanate compound or the diamine compound is preferably 0.8 to 1.1 mol, more preferably 0.95 to 1.08 mol, based on 1.0 mol of the total amount of the acid component, In particular, it is preferable to use 1.0 to 1.08 mol. In the acid component, dicarboxylic acid and tetracarboxylic dianhydride are preferably used in a total amount of 0 to 50 mol%.
[0019]
The number average molecular weight of the polyamideimide resin is sampled at the time of resin synthesis, measured by gel permeation chromatography (GPC) using a standard polystyrene calibration curve, and the synthesis is continued until the target number average molecular weight is reached. In this way, it is managed in the above range.
[0020]
The polyamide imide resin used in the present invention preferably has a number average molecular weight of 5,000 to 50,000. When the number average molecular weight is less than 5,000, various properties such as heat resistance and mechanical properties of the coating tend to decrease when the coating is formed, and when it exceeds 50,000, the coating has an appropriate concentration as a coating. When dissolved in a solvent, the viscosity increases, and the workability during coating tends to be poor. For this reason, the number average molecular weight is preferably from 10,000 to 30,000, and particularly preferably from 15,000 to 25,000.
[0021]
Further, the combined acid value of the carboxyl group obtained by opening the carboxyl group and the acid anhydride group is preferably from 10 to 100, and if it is less than 10, the number of carboxyl groups that react with the basic compound becomes insufficient. When it exceeds 100, the heat-resistant resin composition finally obtained tends to gel over time. For this reason, the combined acid value of the carboxyl group and the carboxyl group obtained by ring-opening the acid anhydride group is more preferably 20 to 80, and particularly preferably 30 to 60.
[0022]
The acid value obtained by combining the carboxyl group of the polyamideimide resin and the carboxyl group obtained by ring-opening the acid anhydride group can be obtained by the following method. First, about 0.5 g of a polyamideimide resin was added, about 0.15 g of 1,4-diazabicyclo [2,2,2] octane was added, about 60 g of N-methyl-2-pyrrolidone and ion-exchanged water were added. Add about 1 ml and stir until the polyamideimide resin is completely dissolved. This is titrated with a potentiometric titrator using a 0.05 mol / l ethanolic potassium hydroxide solution to obtain an acid value obtained by combining the carboxyl group of the polyamideimide resin and the carboxyl group obtained by opening the acid anhydride group. .
[0023]
In the present invention, examples of the basic compound include alkylamines such as triethylamine, tributylamine, triethylenediamine and N-methylmorpholine, alkylanilines such as methylaniline and dimethylaniline, monoethanolamine, diethanolamine, triethanolamine and dipropanolamine. And alkanolamines such as tripropanolamine, N-ethylethanolamine, N, N-dimethylethanolamine, cyclohexanolamine, N-methylcyclohexanolamine, and N-benzylethanolamine. An acidic compound, for example, caustic alkali such as sodium hydroxide or potassium hydroxide or aqueous ammonia may be used without any particular limitation. Preferably, triethylamine, N-methylmorpholine, triethylenediamine, N, N-dimethylethanolamine are used.
[0024]
The basic compound is used in an amount of 1 to 20 equivalents based on the combined acid value of the carboxyl group and the ring-opened acid anhydride group contained in the polyamideimide resin obtained by the reaction in the above organic solvent. If the amount is less than 1 equivalent, it is difficult to make the resin water-soluble, and if it exceeds 20 equivalents, hydrolysis of the resin is promoted, and the viscosity or properties may be reduced by long-term storage. For this reason, the acid value of the combined carboxyl group and the carboxyl group obtained by ring-opening the acid anhydride group is preferably 2 to 10 equivalents, particularly preferably 3 to 8 equivalents.
[0025]
The basic compound forms a salt with the carboxyl group at the terminal of the polyamideimide resin to become a hydrophilic group. The salt may be formed in the coexistence of water, or may be added after adding a basic compound. The temperature for forming the salt is in the range of 0 ° C to 200 ° C, preferably 40 ° C to 130 ° C.
[0026]
Depending on the type and amount of the basic compound and the method of adding water, the form of the obtained aqueous resin composition is an emulsion, a translucent solution, a transparent solution, etc., but from the viewpoint of storage stability and coating workability, it is translucent. Alternatively, it is preferable to use a transparent solution.
As the water, ion-exchanged water is preferably used, and preferably 5 to 99% by weight, more preferably 20 to 60% by weight, based on the total amount of the components (A), (B) and (C). . When the amount is less than 5% by weight, the content of water is small, so that it is not generally referred to as a water-soluble polymer.
[0027]
The blending amount of chromium acetylacetonate is in the range of 0.01 to 20% by weight based on 100% by weight of the polyamideimide resin. When the amount is less than 0.01% by weight, the effect of improving the adhesion becomes small, and when it exceeds 20% by weight, the heat resistance of the coating film tends to gradually decrease. For this reason, the amount of chromium acetylacetonate is preferably 0.05 to 10% by weight, more preferably 0.1 to 8% by weight, based on 100% by weight of the polyamideimide resin. Chromium acetylacetonate can be mixed with the polyamideimide resin as a solution dissolved in a basic polar solvent. As the basic polar solvent, N-methyl-2-pyrrolidone, N, N-dimethylformamide and the like can be used. The concentration of the solution is not particularly limited. For example, 100% by weight of chromium acetylacetonate is dissolved in 900 to 4000% by weight of a basic polar solvent. The method of blending chromium acetylacetonate is not limited to this, but may be any other appropriate method.
[0028]
The heat-resistant resin composition thus obtained is diluted to an appropriate concentration as needed when used. Examples of the diluting solvent include polar solvents such as water, dimethylformamide, dimethylacetamide, dimethylsulfoxide, and N-methyl-2-pyrrolidone, as well as co-solvents such as polyols, lower alkyl etherified compounds, and acetylated compounds thereof. May be used. For example, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, glycerin, trimethylolpropane, isopropyl alcohol, or their monomethyl ethers, monoethyl ethers, monoisopropyl ethers, monobutyl ethers, dimethyl ethers, and the like Acetyl compounds and the like are used.
[0029]
The heat-resistant resin composition according to the present invention is applied to an object to be coated and cured to form a coating film on the surface of the object. When a stainless steel plate is used as the object, a particularly remarkable effect can be obtained.
[0030]
【Example】
Next, examples of the present invention will be described, but the present invention is not limited to these examples.
[0031]
Example 1
1106.2 g of trimellitic anhydride, 1455.8 g of 4,4-diphenylmethane diisocyanate and 2562.0 g of N-methyl-2-pyrrolidone were placed in a flask equipped with a thermometer, a stirrer and a condenser, and dried in a nitrogen stream. The temperature was gradually raised to 130 ° C. over about 2 hours while stirring. The temperature was kept at 130 ° C. while paying attention to the rapid bubbling of carbon dioxide gas generated by the reaction. The heating was continued for about 6 hours, and the reaction was stopped to obtain a polyamideimide resin solution.
[0032]
The nonvolatile content (200 ° C.-2h) of this polyamideimide resin solution was about 50% by weight, and the viscosity (30 ° C.) was about 85.0 Pa · s. The number average molecular weight of the polyamide-imide resin was about 17,000, and the combined acid value of the carboxyl group and the carboxyl group obtained by ring-opening the acid anhydride group was about 40. The number average molecular weight was measured under the following conditions.
Model: Hitachi L6000 (trade name)
Detector: Hitachi L4000 UV (trade name)
Wavelength: 270 nm
Data processor: ATT 8
Column: Gelpack GL-S300MDT-5 × 2
Column size: 8mmφ × 300mm
Solvent: DMF / THF = 1/1 (liter) + phosphoric acid 0.06M + lithium bromide 0.06M
Sample concentration: 5mg / 1ml
Injection volume: 5 μl
Pressure: 49 kgf / cm ² (4.8 × 10 ⁶ Pa)
Flow rate: 1.0 ml / min
[0033]
2,700 g of this polyamide-imide resin solution was put into a flask equipped with a thermometer, a stirrer, and a condenser, and the temperature was gradually raised to 50 ° C. while stirring in a dried nitrogen stream. When the temperature reached 50 ° C., 447.1 g (4 equivalents) of triethylamine was added, and the mixture was sufficiently stirred at 50 ° C., and then ion-exchanged water was gradually added with stirring. Eventually, ion-exchanged water was added up to 1348.8 g (30% by weight) to obtain a transparent and uniform heat-resistant resin composition.
1.7% by weight of N-methyl-2-pyrrolidone solution of chromium acetylacetonate (10% by weight of non-volatile content) is mixed with 100% by weight (30% by weight of non-volatile content) of the heat-resistant resin composition prepared by the above method. And a heat-resistant resin composition.
[0034]
Example 2
382.9 g of trimellitic anhydride, 503.9 g of 4,4'-diphenylmethane diisocyanate, and 886.8 g of N-methyl-2-pyrrolidone were placed in a flask equipped with a thermometer, a stirrer, and a condenser, and dried in a nitrogen stream. The temperature was gradually raised to 80 ° C. over about one hour while stirring at 80 ° C. The temperature was kept at 80 ° C. while paying attention to the rapid bubbling of carbon dioxide gas generated by the reaction. After heating was continued for about 7 hours from the start of the heating, the reaction was stopped to obtain a polyamideimide resin solution.
The nonvolatile matter (200 ° C.-2h) of this polyamideimide resin solution was about 50% by weight, and the viscosity (30 ° C.) was about 80.0 Pa · s. The number average molecular weight of the polyamide-imide resin was about 15,000, and the combined acid value of the carboxyl group and the carboxyl group obtained by ring-opening the acid anhydride group was about 50.
200 g of the polyamideimide resin solution was put into a flask equipped with a thermometer, a stirrer, and a cooling tube, and the temperature was gradually raised to 90 ° C. while stirring in a dried nitrogen stream. When the temperature reached 90 ° C., 70.8 g (8 equivalents) of N-methylmorpholine was added, and the mixture was sufficiently stirred while maintaining the temperature at 90 ° C., and then ion-exchanged water was gradually added with stirring. Finally, ion-exchanged water was added until the amount became 180.5 g (40% by weight) to obtain a transparent and uniform heat-resistant resin composition.
4.4% by weight of a solution of chromium acetylacetonate in N-methyl-2-pyrrolidone (5% by weight of non-volatile content) is mixed with 100% by weight of heat-resistant resin composition (22% by weight of non-volatile content) prepared by the above method. And a heat-resistant resin composition.
[0035]
Example 3
233.8 g of trimellitic anhydride, 98.0 g of benzophenonetetracarboxylic anhydride, 384.6 g of 4,4'-diphenylmethane diisocyanate, and 1671.6 g of N-methyl-2-pyrrolidone were placed in a flask equipped with a thermometer, stirrer, and condenser. Then, the temperature was gradually raised to 120 ° C. over about 1 hour while stirring in a dried nitrogen stream. The temperature was gradually raised to 150 ° C. while paying attention to rapid bubbling of carbon dioxide gas generated by the reaction. After heating was continued for 5 hours from the start of heating, the reaction was stopped to obtain a polyamideimide resin solution.
The nonvolatile content (200 ° C.-2h) of this polyamideimide resin solution was about 30% by weight, and the viscosity (30 ° C.) was about 2.1 Pa · s. The number average molecular weight of the polyamideimide resin was about 23,000, and the acid value of the carboxyl group and the acid anhydride group was about 30.
200 g of this polyamide-imide resin solution was put into a flask equipped with a thermometer, a stirrer, and a condenser, and the temperature was gradually raised to 110 ° C. while stirring in a dried nitrogen stream. When the temperature reached 110 ° C., 17.6 g (6 equivalents) of N, N-dimethylethanolamine was added, and the mixture was sufficiently stirred at 110 ° C., and then ion-exchanged water was gradually added with stirring. Finally, ion-exchanged water was added until the amount became 217.6 g (50% by weight) to obtain a transparent and uniform heat-resistant resin composition.
100% by weight (14% by weight of non-volatile content) of the heat-resistant resin composition prepared by the above method was mixed with 7.0% by weight of a solution of chromium acetylacetonate in N-methyl-2-pyrrolidone (10% by weight of non-volatile content). And a heat-resistant resin composition.
[0036]
Comparative Example 1
876.9 g of trimellitic anhydride, 1153.8 g of 4,4'-diphenylmethane diisocyanate and 4,738.3 g of N-methyl-2-pyrrolidone were placed in a flask equipped with a thermometer, a stirrer and a condenser, and dried under nitrogen. The temperature was gradually raised to 110 ° C. over about 1 hour while stirring in a gas stream. The temperature was gradually raised to 120 ° C. while paying attention to rapid bubbling of carbon dioxide gas generated by the reaction. After heating was continued for about 8 hours from the start of heating, the reaction was stopped to obtain a polyamideimide resin solution.
The nonvolatile content (200 ° C.-2 h) of this polyamideimide resin solution was about 30% by weight, and the viscosity (30 ° C.) was about 1.8 Pa · s. The number average molecular weight of the polyamideimide resin was about 21,000, and the combined acid value of the carboxyl group and the carboxyl group obtained by ring-opening the acid anhydride group was about 35.
[0037]
The coating materials obtained in Examples 1, 2 and 3 and Comparative Example 1 were applied to a stainless steel plate (SUS430) and baked at 300 ° C. for 30 minutes to form a coated plate having a film thickness of 10 μm. With respect to the stainless steel sheet on which the coating film was formed, the adhesion at the initial stage and after exposure to 300 ° C. for a predetermined time was measured in accordance with the old JIS K5400 (%, crosscut residual ratio). Table 1 shows the results.
[0038]
[Table 1]

[0039]
In the initial stage of Comparative Example 1, the reason why there is a range in the numerical value of the adhesion is that there is a variation between lots in the initial adhesion. Indicates that there is no
From Table 1, the paints obtained in Examples 1, 2 and 3 have a reduced organic solvent content as compared with the paints of Comparative Examples, and the paints obtained in Examples 1, 2 and 3 It can be seen that the obtained coating film has remarkably excellent adhesion at the initial stage and after deterioration at 300 ° C. as compared with the coating film obtained from the coating material of the comparative example.
[0040]
【The invention's effect】
The heat-resistant resin composition of the present invention, when formed into a coating film, does not decrease its adhesiveness to a stainless steel plate even when exposed to high temperatures, and has a reduced organic solvent content, so that it has various heat-resistant properties. Among coating applications, it is particularly useful for high heat-resistant applications, is free from environmental pollution and working environment deterioration, and is advantageous in terms of safety and hygiene. Therefore, it has great industrial effectiveness.

Claims (7)

(A) a polyamideimide resin obtained by reacting a diisocyanate compound or a diamine compound with a tribasic anhydride or a tribasic anhydride chloride in a basic polar solvent, (B) a basic compound, and (C) water And (D) a heat-resistant resin composition containing chromium acetylacetonate. The basic compound (B) has an acid value of 1 based on the combined carboxyl group contained in the polyamideimide resin (A) and the carboxyl group obtained by ring-opening the acid anhydride group in the polyamideimide resin. The heat-resistant resin composition according to claim 1, which is blended in an amount of from 20 to 20 equivalents. The heat-resistant resin composition according to claim 1, wherein the water as the component (C) is blended in an amount of 5 to 99% by weight based on the total amount of the components (A), (B), and (C). The number average molecular weight of a polyamide imide resin is 5,000-50,000, and the acid value which combined the carboxyl group which opened the carboxyl group and the acid anhydride group was 10-100. Heat-resistant resin composition. The heat-resistant resin composition according to claim 1, wherein the basic compound as the component (B) is an alkylamine or an alkanolamine. The heat-resistant resin composition according to any one of claims 1 to 5, wherein the chromium acetylacetonate (D) is incorporated in an amount of 0.01 to 20% by weight based on 100% by weight of the heat-resistant resin composition. A paint comprising the heat-resistant resin composition according to claim 1 as a coating film component.