JP3641765B2 - Epoxy resin and curable composition containing the epoxy resin - Google Patents

Description

【０００６】
（式中、ｎ≧０、ｍ≧０、Ｒ₁は（ターシャリー）ブチル基を示し、１≦（ａ＋ａ′）≦４、Ｒ₂は（ターシャリー）ブチル基、又は水素原子からなり、１≦（ｂ＋ｂ′）≦４である。Ｘは、−ＣＨ（ＣＨ₃）₂ −基を表す）
【０００７】
本発明に用いるアルキル基置換ビスフェノール類として代表的なものとしては、ジターシャリーブチルビスフェノールＡ、テトラターシャリーブチルビスフェノールＡ、ジセコンダリーブチルビスフェノールＡ、及びこれらの混合物が挙げられるが、好ましくはターシャリーブチル化ビスフェノールＡである。
【０００８】
本発明のエポキシ樹脂は（ターシャリー）ブチル化ビスフェノールＡをエピハロヒドリンでアルカリ金属水酸化物の存在下でエポキシ化する従来公知の方法により得ることができる。エピハロヒドリンとしてはエピクロロヒドリン、エピブロモヒドリン、エピヨードヒドリン等が挙げられるが、エピクロロドリンが望ましい。
アルキル化ビスフェノール類のフェノール性水酸基１モルに対してエピハロヒドリンを１．５〜１５モル、より好ましくは３〜８モルの過剰量を用い、アルカリ金属水酸化物の使用量はアルキル化ビスフェノール類の水酸基当量１に対して０．８〜１．３モルの範囲で固形又は水溶液として加える。
反応温度は４０〜１２０℃、圧力５０〜７６０ｍｍＨｇで生成した水を系外に除去しながら０．５〜１５時間反応させる。反応終了後に過剰のエピハロヒドリンを留去した後、メチルイソブチルケトンやトルエン等の溶剤に溶解して、さらに生成したエポキシ樹脂の加水分解性塩素に対して１〜５０モルのアルカリ金属水酸化物を添加して精製反応を行った後、副生成した塩を水性又は濾過等により除去し、溶媒を留去することにより本発明のエポキシ樹脂を得ることができる。
【０００９】
前述のターシャリー）ブチル化ビスフェノールＡ型エポキシ樹脂はさらにビスフェノール類又はアルキル基置換ビスフェノール類及びそれらの混合物との重付加反応によりエポキシ当量２００〜２，０００ｇ／ｅｑの任意の分子量のエポキシ樹脂を得ることができる。エポキシ当量２００ｇ／ｅｑ以下のものは合成が困難であり、エポキシ当量が２，０００ｇ／ｅｑを超えるものは架橋密度が踈になり耐食性、耐薬品性が損なわれミネラルスピリッツに対する溶解性も悪くなる為であり、好ましくは２５０〜１，０００ｇ／ｅｑである。かかるエポキシ樹脂の合成法は、特に限定されることなく従来より知られている公知の方法に従って行われる。公知の方法として上記原料を一括投入後８０〜２２０℃にて触媒存在下において１〜２０時間で反応させる。かかる触媒としては、トリエチルアミン、ジメチルベンジルアミン、ピリジンなどの３級アミン、テトラメチルアンモニウムクロライド、ベンジルトリメチルアンモニウムクロライド、トリフェニルホスホニウムブロマイドなどの４級アンモニウム塩、水酸化ナトリウム、水酸化カリウム、水酸化リチウムなどのアルカリ金属水酸化物、トリフェニルホスフィン、トリエチルホスフィンなどの有機リン化合物などが用いられる。
【００１０】
本発明の組成物には、５０〜１００重量％以上のアルキル基置換ビスフェノール型エポキシ樹脂とビスフェノール型エポキシ樹脂とを混合して用いることができる。ビスフェノール型エポキシ樹脂の含有量が５０重量％を超えるとミネラルスピリッツに対する溶解性が落ちるためである。ここで用いられるビスフェノール型エポキシ樹脂としてはビスフェノールＡ型エポキシ樹脂，ビスフェノールＦ型エポキシ樹脂、ビスフェノールＳ型エポキシ樹脂，ビスフェノールＡＤ型エポキシ樹脂及びこれらの混合物が挙げられるが、好ましくはビスフェノールＡ型及びビスフェノールＦ型エポキシ樹脂である。またエポキシ樹脂の分子量範囲としては３２０から１，５００程度のものまで用いることができる。これらの市販のエポキシ樹脂としては東都化成社製のＹＤ−１２８，ＹＤ−１３４，ＹＤ−０１１，ＹＤＦ−１７０，ＹＤＦ−２００１等が挙げられる。
【００１１】
本発明の組成物で用いることのできる硬化剤としては、アミン系硬化剤、メルカプタン系硬化剤、酸無水物系硬化剤等が挙げられるが、重防食用途にはアミン系硬化剤が最も好ましい。アミン系硬化剤としては、ポリアミノアミド類、エポキシ樹脂アミンアダクト、脂肪族ポリアミン、変性ポリアミン、第３アミン、ヒドラジド、イミダゾール等通常のエポキシ樹脂に使用される硬化剤が使用可能であるが、特にポリアミノアミド類、エポキシ樹脂アミンアダクトが好ましい。
【００１２】
本発明の組成物で用いられる溶剤としては、引火点４０℃以上の脂肪族系溶剤（ミネラルスピリッツ）の他に、必要に応じてトルエン、キシレン、及び高沸点ナフサなどの芳香族系溶剤、ケトン類、アルコール類、エステル類、グリコールエーテル類及びそれらの混合物も用いることができる。
【００１３】
本発明のエポキシ樹脂による組成物はエポキシ樹脂単独で用いることも出来るが、必要に応じて石油樹脂、クマロンインデン樹脂、キシレン樹脂、ケトン樹脂等より選ばれた１種又は２種以上の樹脂を所望の目的範囲で含有せしめることが出来る。
本発明の組成物には、各種用途に応じてタルク、炭酸カルシウム、シリカ、カーボンなどの充填材や、ベンガラ、酸化チタン、硫化亜鉛、酸化鉄などの顔料及び増粘剤、消泡剤、可塑剤などの添加剤適量配合することが出来る。塗装手段としては硬化剤成分を除く前記成分の混合物２本ロール、ボールミル、サンドグラインドミル等の分散装置にて混合分散することにより塗料を調整することが出来る。これを塗装直前に硬化剤と混合し、吹き付け塗り、ローラー塗り、刷毛塗り等の通常の塗装手段により塗装し、自然乾燥、強制乾燥により硬化塗膜が形成される。
【００１４】
【発明の効果】
本発明のエポキシ樹脂は高引火点の脂肪族溶剤に可溶であり、該樹脂を用いた硬化性組成物は、塗装時の作業環境を改善することができ、また旧塗膜上に塗装したときに旧塗膜を溶解又は膨潤させる等のリフティングを防ぐことが出来る。
【００１５】
【実施例及び比較例】
以下、実施例及び比較例に基づき本発明を具体的に説明するが、本発明はこれら実施例に限定されるものではない。得られた樹脂については、次の試験法によって行った。
（１）エポキシ当量（固形分値）はＪＩＳ Ｋ７２３６により測定した。
（２）低温溶解性は、各樹脂をミネラルスピリッツに溶解して樹脂分７０％のエポキシ樹脂ワニスとして、５℃で２４時間静置した後分離の有無を目視で判定した。
○ 分離なし、：× 分離（３）ＧＰＣ測定は、東ソー（株）製ＨＬＣ−８０２Ａ型高速ＧＰＣ装置で内蔵のＲＩ検出器を使用した。移動相にはテトラヒドロフランを用いて、流速１．０ｍＬ／ｍｉｎで測定を行った。ＧＰＣカラムは同じく東ソー（株）製Ｇ４０００Ｈ８、Ｇ３０００Ｈ８、Ｇ２０００Ｈ８各１本を用いた。分子量測定はポリスチレン検量線により求めた。
参考例１
撹拌噐、温度計、窒素ガス導入装置、滴下装置、冷却管及び油水分離装置を備えた内容量１のガラスフラスコに本州化学工業社製ＢｉｓＯＴＢＰ−Ａ（ターシャリーブチル化ビスフェノールＡ；フェノール性水酸基当量１７０ｇ／ｅｑ，融点１１５℃）１５０部、エピクロロヒドリン３０８部を仕込み、窒素ガスを流しながら７０℃まで加熱して溶解した。その後同温度に保ちながら、４８％水酸化ナトリウム水溶液３．７部を１時間毎に３回添加後一時間同温度で反応を行った。その後窒素ガスの導入を中止して、系内を２４０ｍｍＨｇの減圧にして７５℃まで加熱して計内の水分をエピクロロヒドリンと共沸留出水させ油水分離装置を用いて系外に分離除去した。その後同条件を保ちながら４８％水酸化ナトリウム水溶液５５．８部を３時間で滴下した。この間系内の水分はエピクロロヒドリンと共沸留出水させ系外に分離除去した。水酸化ナトリウム滴下終了後さらに３０分反応を継続した後、未反応のエピクロロヒドリンを１０ｍｍＨｇの減圧下、１８０℃の温度で５分間保持して減圧回収した。次にメチルイソブチルケトンを３９０部加え、生成したエポキシ樹脂を溶解した後１５％水酸化ナトリウム水溶液２０部を加え８０℃で２時間反応させた。次に水２６０部を加えて反応で生成した食塩を溶解させて分液、除去した後、リン酸水溶液で中和し、水洗水が中性になるまで樹脂溶液を数回水洗した。さらに５ｍｍＨｇ以下の減圧下、１８０℃の温度で５分間保持してメチルイソブチルケトンを留去しエポキシ樹脂を得た。得られた樹脂のエポキシ当量は２６５ｇ／ｅｑで低温溶解性は○印であった。また、該エポキシ樹脂のＧＰＣチャ−ト、溶出時間（ｍｉｎ）と応答量（ｍＶ）及び溶出時間（ｍｉｎ）と分子量の対数（ＬｏｇＭ）を同時にプロットしたもの図１に示した。同時に赤外吸収スペクトルを図２に示した。
【００１６】
参考例２
参考例１で得られた（ターシャリー）ブチル化ビスフェノールＡのジグリシジルエーテル８７５部にＢＰＡ１２５部仕込み１２０℃まで昇温してトリフェニルホスフィンをＢＰＡに対して１０００ｐｐｍ添加し、１５０℃まで昇温、同温度で反応を行いエポキシ当量が設定値以上になったところで反応終了とした。得られた樹脂のエポキシ当量は４７８ｇ／ｅｑで、低温溶解性は○印であった。
【００１７】
参考例３
参考例１で得られた（ターシャリー）ブチル化ビスフェノールＡのジグリシジルエーテル７５０部に東都化成社製ＹＤ−１２８（ビスフェノールＡ型液状エポキシ樹脂；エポキシ当量１８７ｇ／ｅｑ、粘度１２，８００ｍＰａ・ｓ／２５℃）を２５０部を加えて８０℃まで昇温、溶解して全体が均一になるのを確認して抜き出した。得られた樹脂のエポキシ当量は２３９ｇ／ｅｑで、低温溶解性は○印であった。
【００１８】
比較参考例１
参考例１の（ターシャリー）ブチル化ビスフェノールＡをビスフェノールＡに変更した以外は同じ条件でエポキシ化を行いエポキシ樹脂を得た。得られた樹脂のエポキシ当量は１８７ｇ／ｅｑで、低温溶解性は×印であった。
【００１９】
比較参考例２
参考例１の（ターシャリー）ブチル化ビスフェノールＡをビスフェノールＣ（メチル化ビスフェノールＡ）に変更した以外は同じ条件でエポキシ化を行いエポキシ樹脂を得た。得られた樹脂のエポキシ当量は２１０ｇ／ｅｑで、低温溶解性は×印であった。
【００２０】
比較参考例３
参考例１で得られた（ターシャリー）ブチル化ビスフェノールＡのジグリシジルエーテル４００部にＹＤ−１２８を６００部を加えて８０℃まで昇温、溶解して混合エポキシ樹脂を得た。得られた樹脂のエポキシ当量は２１２ｇ／ｅｑで、低温溶解性は×印であった。
【００２１】
実施例１〜３及び比較例１〜３
参考例１〜３及び比較参考例１〜３で得られたエポキシ樹脂をミネラルスピリッツに樹脂分７０％で溶解した。このエポキシ樹脂ワニス１００部に表−１に示す量でアミン系硬化剤（東都化成社製ポリアミノアミドＺＸ−１４７８；アミン価１０６ｍｇＫＯＨ／ｇ）を配合した。更に酸化チタン２２部、沈降性硫酸バリウム１８部、燐酸亜鉛６部を配合して塗料を調整した。
得られた塗料を軟鋼板ＳＰＣＣ−ＳＢ（１．６×７０×１５０ｍｍ）のメチルエチルケトンでの脱脂後にサンドブラスト処理を行ったものにバーコーターで乾燥膜厚１００μｍになるように塗布し、２０℃、７日間乾燥させた。得られた塗膜の外観、密着性、耐食性の各性能試験を評価した結果を表１に示した。
尚、塗膜の外観は目視で判定した○：良好△：やや良好×：不良。
また、密着性は、ＪＩＳ Ｋ−５４００の付着性の碁盤目テープ剥離試験法により評価し、ゴバン目１００個をカッターナイフで切り込み、セロハンテープにて剥離試験を行い、塗膜残存数を測定した。また、耐食性についてはＪＩＳ Ｋ５４００−７，８に準拠して３００時間塩水噴霧試験をした後、塗膜の外観について目視により発錆性を評価した○：良好△：錆発生により若干の膨れあり×：錆発生により著しい膨れあり。
【００２２】
【表１】

【００２３】
表１から明らかなように、本発明の（ターシャリー）ブチル化ビスフェノールＡ型エポキシ樹脂と硬化剤より成る硬化性組成物はミネラルスピリッツに対する溶解性に優れ、得られる塗膜は従来のビスフェノール型エポキシ樹脂と同等の密着性、耐食性を有している。
【図面の簡単な説明】
【図１】 参考例１で得られた（ターシャリー）ブチル化ビスフェノールＡ型エポキシ樹脂のＧＰＣチャートであり、溶出時間（ｍｉｎ）と応答量（ｍＶ）及び溶出時間（ｍｉｎ）と分子量の対数（ＬｏｇＭ）を同時にブロットしたものである。
【図２】 参考例１で得られた（ターシャリー）ブチル化ビスフェノールＡ型エポキシ樹脂の赤外吸収スペクトルチャートであり、縦軸は吸収強度を、横軸は吸収波長を示す。[0001]
[Technical field to which the present invention pertains]
The present invention completely dissolves in a hydrocarbon-based solvent having a high flash point at room temperature, and includes a wide range of paints, adhesives, insulating materials, laminated plate materials, electronic materials, casting materials, anti-crystallization materials, etc. The present invention relates to an epoxy resin that can be used in the field and a composition thereof, and more particularly, to provide a curable composition from which a cured product having excellent corrosion resistance, water resistance, strength, and the like can be obtained.
[0002]
[Prior art]
Conventionally, epoxy resins have been widely used for heavy anticorrosion paints for bridges, tanks, ships, etc. due to their excellent corrosion resistance, adhesion, chemical resistance, etc., but in general, bisphenol type epoxy resins are used. It is used by being dissolved in a low flash point, low boiling point organic solvent such as xylene or toluene. For this reason, there have been problems such as deterioration of working environment due to solvent odor at the time of painting, fire hazard, and swelling and lifting of the old paint film when applied to the old paint film.
In order to improve these problems, it is necessary to use a solvent with a low flash point and a high flash point. However, conventional epoxy resins have low solubility in these solvents, so the paint is cloudy and has a high viscosity. There was a problem of becoming. Moreover, as a method for improving these problems, JP-A-4-11623 and JP-B-7-68491 disclose modification by dissolving in a mixed aromatic hydrocarbon solvent having 9 to 11 carbon atoms such as Solvesso 100. Epoxy resins have been reported, but there was a problem that aromatic solvents could not eliminate odor during painting work. For this reason, there has been a demand for the appearance of an epoxy resin coating that can be dissolved in an aliphatic hydrocarbon having a high flash point, such as mineral spirits, and that can provide a coating having excellent adhesion and corrosion resistance.
[0003]
[Problems to be solved by the present invention]
In view of the current situation, the present inventors have studied to develop an epoxy resin that is soluble in an aliphatic solvent with a high flash point and a low odor, and as a result, the present invention has been completed. That is, the present invention provides an epoxy resin that completely dissolves in an aliphatic solvent having a flash point of 40 ° C. or higher at room temperature and gives a coating film excellent in adhesion, corrosion resistance, and water resistance, and a curable composition thereof. It is.
[0004]
[Means for solving the problems]
As a result of intensive studies to solve such problems, the present inventors have (tertiary) butylated bisphenol A type epoxy tree having an epoxy equivalent of 180 to 2,000 g / eq represented by the following general formula (1). The present inventors have found that an epoxy resin composition containing a fat and an epoxy curing agent as essential components is an optimal means for solving these problems, and has completed the present invention.
[0005]
[Chemical formula 2]

[0006]
(Wherein n ≧ 0, m ≧ 0, R ₁ represents a (tertiary) butyl group , 1 ≦ (a + a ′) ≦ 4, R ₂ is a (tertiary) butyl group or a hydrogen atom, ≦ (b + b ′) ≦ 4, X represents a —CH (CH ₃ ) ₂ — group )
[0007]
As typical example of the alkyl group substituted bisphenols used in the present invention, di-tert-butyl bisphenol A, tetra-tertiary-butyl bisphenol A, Jise Con Daly butyl bisphenol A, but 及 Beauty mixtures thereof, preferably tertiary butylated Bisphenol A.
[0008]
The epoxy resin of the present invention can be obtained by a conventionally known method in which (tertiary) butylated bisphenol A is epoxidized with epihalohydrin in the presence of an alkali metal hydroxide. Examples of the epihalohydrin include epichlorohydrin, epibromohydrin, epiiodohydrin, and the like, but epichlorohydrin is preferable.
An excess of 1.5 to 15 mol, more preferably 3 to 8 mol of epihalohydrin is used per 1 mol of the phenolic hydroxyl group of the alkylated bisphenol, and the amount of alkali metal hydroxide used is the hydroxyl group of the alkylated bisphenol. It is added as a solid or an aqueous solution in the range of 0.8 to 1.3 mol per equivalent of 1.
The reaction temperature is 40 to 120 ° C. and the pressure is 50 to 760 mmHg, and the reaction is carried out for 0.5 to 15 hours while removing water generated outside the system. Excess epihalohydrin is distilled off after completion of the reaction, then dissolved in a solvent such as methyl isobutyl ketone or toluene, and 1-50 mol of alkali metal hydroxide is added to the hydrolyzable chlorine of the epoxy resin produced. Then, after carrying out the purification reaction, the by-produced salt is removed by aqueous or filtration and the solvent is distilled off to obtain the epoxy resin of the present invention.
[0009]
The above-mentioned tertiary) butylated bisphenol A type epoxy resin further obtains an epoxy resin having an arbitrary molecular weight of an epoxy equivalent of 200 to 2,000 g / eq by polyaddition reaction with bisphenols or alkyl group-substituted bisphenols and mixtures thereof. be able to. Those having an epoxy equivalent of 200 g / eq or less are difficult to synthesize, and those having an epoxy equivalent of more than 2,000 g / eq have a cross-linking density that is inferior in corrosion resistance and chemical resistance, resulting in poor solubility in mineral spirits. And preferably 250 to 1,000 g / eq. The method for synthesizing such an epoxy resin is not particularly limited, and is performed according to a conventionally known method. As a known method, the raw materials are reacted together at 80 to 220 ° C. in the presence of a catalyst for 1 to 20 hours. Such catalysts include tertiary amines such as triethylamine, dimethylbenzylamine and pyridine, quaternary ammonium salts such as tetramethylammonium chloride, benzyltrimethylammonium chloride and triphenylphosphonium bromide, sodium hydroxide, potassium hydroxide and lithium hydroxide. Alkali metal hydroxides such as organic phosphorus compounds such as triphenylphosphine and triethylphosphine are used.
[0010]
In the composition of the present invention, 50 to 100% by weight or more of an alkyl group-substituted bisphenol type epoxy resin and a bisphenol type epoxy resin can be mixed and used. This is because if the content of the bisphenol-type epoxy resin exceeds 50% by weight, the solubility in mineral spirits decreases. Examples of the bisphenol type epoxy resin used here include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AD type epoxy resin, and mixtures thereof, preferably bisphenol A type and bisphenol F. Type epoxy resin. The molecular weight range of the epoxy resin can be from 320 to 1,500. Examples of these commercially available epoxy resins include YD-128, YD-134, YD-011, YDF-170, and YDF-2001 manufactured by Tohto Kasei Co., Ltd.
[0011]
Examples of the curing agent that can be used in the composition of the present invention include amine-based curing agents, mercaptan-based curing agents, acid anhydride-based curing agents, and the like, and amine-based curing agents are most preferable for heavy anticorrosion applications. As the amine-based curing agent, polyaminoamides, epoxy resin amine adducts, aliphatic polyamines, modified polyamines, tertiary amines, hydrazides, imidazoles, and other curing agents used for ordinary epoxy resins can be used. Amides and epoxy resin amine adducts are preferred.
[0012]
As the solvent used in the composition of the present invention, in addition to an aliphatic solvent (mineral spirit) having a flash point of 40 ° C. or higher, an aromatic solvent such as toluene, xylene, and high-boiling naphtha, a ketone, if necessary , Alcohols, esters, glycol ethers and mixtures thereof can also be used.
[0013]
The epoxy resin composition of the present invention can be used alone, but if necessary, one or more resins selected from petroleum resin, coumarone indene resin, xylene resin, ketone resin, etc. may be used. It can be contained in a desired target range.
The composition of the present invention includes fillers such as talc, calcium carbonate, silica and carbon, pigments and thickeners such as bengara, titanium oxide, zinc sulfide and iron oxide, antifoaming agents, plastics, etc. An appropriate amount of additives such as an agent can be blended. As the coating means, the paint can be adjusted by mixing and dispersing in a dispersing device such as a two-roll mixture of the above components excluding the curing agent component, a ball mill, a sand grind mill or the like. This is mixed with a curing agent immediately before coating, and is applied by ordinary coating means such as spray coating, roller coating, or brush coating, and a cured coating film is formed by natural drying or forced drying.
[0014]
【The invention's effect】
The epoxy resin of the present invention is soluble in an aliphatic solvent having a high flash point, and the curable composition using the resin can improve the working environment at the time of coating, and is coated on the old coating film. Sometimes lifting such as dissolving or swelling the old paint film can be prevented.
[0015]
[Examples and Comparative Examples]
EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example and a comparative example, this invention is not limited to these Examples. About obtained resin, it carried out by the following test method.
(1) The epoxy equivalent (solid content value) was measured according to JIS K7236.
(2) The low-temperature solubility was determined by visual observation of the presence or absence of separation after each resin was dissolved in mineral spirits and allowed to stand at 5 ° C. for 24 hours as an epoxy resin varnish having a resin content of 70%.
○ No separation: × Separation (3) For GPC measurement, a built-in RI detector was used in an HLC-802A type high-speed GPC device manufactured by Tosoh Corporation. Tetrahydrofuran was used as the mobile phase, and measurement was performed at a flow rate of 1.0 mL / min. The GPC column used was one G4000H8, G3000H8, and G2000H8 manufactured by Tosoh Corporation. The molecular weight was determined by a polystyrene calibration curve.
Reference example 1
BisOTBP-A (tertiary butylated bisphenol A; phenolic hydroxyl group equivalent) manufactured by Honshu Chemical Industry Co., Ltd. was added to a glass flask having an internal volume of 1 equipped with a stirrer, a thermometer, a nitrogen gas introducing device, a dropping device, a cooling pipe and an oil / water separator (170 g / eq, melting point 115 ° C.) 150 parts and epichlorohydrin 308 parts were charged and dissolved by heating to 70 ° C. while flowing nitrogen gas. Thereafter, while maintaining the same temperature, 3.7 parts of 48% aqueous sodium hydroxide solution was added three times every hour, and the reaction was carried out at the same temperature for 1 hour. And thereafter stops the introduction of nitrogen gas, in the outside the system using water oil-water separation apparatus is epichlorohydrin KyonieTome Izumi 75 ° C. until in pressurized heating and the meter in the vacuum of 240mmHg system Separated and removed. Thereafter, 55.8 parts of a 48% aqueous sodium hydroxide solution was added dropwise over 3 hours while maintaining the same conditions. During this period, water in the system was separated and removed from the system by azeotropic distillation with epichlorohydrin. After completion of the sodium hydroxide addition, the reaction was continued for another 30 minutes, and then unreacted epichlorohydrin was recovered under reduced pressure by holding at a temperature of 180 ° C. for 5 minutes under a reduced pressure of 10 mmHg. Next, 390 parts of methyl isobutyl ketone was added to dissolve the produced epoxy resin, and then 20 parts of a 15% aqueous sodium hydroxide solution was added and reacted at 80 ° C. for 2 hours. Next, 260 parts of water was added to dissolve and remove the sodium chloride produced by the reaction, followed by neutralization with an aqueous phosphoric acid solution, and the resin solution was washed several times until the washing water became neutral. Furthermore, it hold | maintained for 5 minutes at the temperature of 180 degreeC under pressure reduction of 5 mmHg or less, and methyl isobutyl ketone was distilled off and the epoxy resin was obtained. The epoxy equivalent of the obtained resin was 265 g / eq, and the low-temperature solubility was ◯. The GPC chart, elution time (min), response amount (mV), elution time (min) and logarithm of molecular weight (Log M) of the epoxy resin are plotted simultaneously in FIG. At the same time, the infrared absorption spectrum is shown in FIG.
[0016]
Reference example 2
To 875 parts of (tertiary) butylated bisphenol A diglycidyl ether obtained in Reference Example 1 was charged 125 parts of BPA, the temperature was raised to 120 ° C, and 1000 ppm of triphenylphosphine was added to BPA, and the temperature was raised to 150 ° C. The reaction was carried out at the same temperature, and the reaction was terminated when the epoxy equivalent exceeded the set value. The epoxy equivalent of the obtained resin was 478 g / eq, and the low-temperature solubility was ◯.
[0017]
Reference example 3
To 750 parts of (tertiary) butylated bisphenol A diglycidyl ether obtained in Reference Example 1, YD-128 (bisphenol A type liquid epoxy resin manufactured by Tohto Kasei Co .; epoxy equivalent 187 g / eq, viscosity 12,800 mPa · s / (25 ° C.) was added to 250 parts and the temperature was raised to 80 ° C. and dissolved to confirm that the whole became uniform. The epoxy equivalent of the obtained resin was 239 g / eq, and the low-temperature solubility was ◯.
[0018]
Comparative Reference Example 1
Epoxidation was carried out under the same conditions except that (tertiary) butylated bisphenol A in Reference Example 1 was changed to bisphenol A to obtain an epoxy resin. The epoxy equivalent of the obtained resin was 187 g / eq, and the low-temperature solubility was x.
[0019]
Comparative Reference Example 2
Epoxy resin was obtained by epoxidation under the same conditions except that (tertiary) butylated bisphenol A of Reference Example 1 was changed to bisphenol C (methylated bisphenol A). The epoxy equivalent of the obtained resin was 210 g / eq, and the low-temperature solubility was x.
[0020]
Comparative Reference Example 3
600 parts of YD-128 was added to 400 parts of (tertiary) butylated bisphenol A diglycidyl ether obtained in Reference Example 1, and the mixture was heated to 80 ° C. and dissolved to obtain a mixed epoxy resin. The epoxy equivalent of the obtained resin was 212 g / eq, and the low-temperature solubility was x.
[0021]
Examples 1 to 3 and Comparative Examples 1 to 3
The epoxy resins obtained in Reference Examples 1 to 3 and Comparative Reference Examples 1 to 3 were dissolved in mineral spirits at a resin content of 70%. In 100 parts of this epoxy resin varnish, an amine curing agent (polyaminoamide ZX-1478 manufactured by Tohto Kasei Co., Ltd .; amine value 106 mgKOH / g) was blended in the amount shown in Table-1. Further, 22 parts of titanium oxide, 18 parts of precipitated barium sulfate, and 6 parts of zinc phosphate were blended to prepare a coating material.
The obtained paint was degreased with methylethylketone of mild steel plate SPCC-SB (1.6 × 70 × 150 mm) and then sandblasted and applied with a bar coater to a dry film thickness of 100 μm. Dried for days. Table 1 shows the results of evaluating the performance tests of the appearance, adhesion, and corrosion resistance of the obtained coating film.
In addition, the external appearance of the coating film was determined visually. ◯: Good Δ: Slightly good X: Poor
Also, the adhesion was evaluated by the adhesive cross-cut tape peeling test method of JIS K-5400, 100 gobangs were cut with a cutter knife, the peel test was performed with a cellophane tape, and the number of remaining coating films was measured. . Moreover, about the corrosion resistance, after performing the salt spray test for 300 hours based on JISK5400-7,8, the rusting property was visually evaluated about the external appearance of the coating film. : Significant swelling due to rust.
[0022]
[Table 1]

[0023]
As is apparent from Table 1, the curable composition comprising the ( tertiary) butylated bisphenol A type epoxy resin and the curing agent of the present invention has excellent solubility in mineral spirits, and the resulting coating film is a conventional bisphenol type epoxy. Adhesion and corrosion resistance equivalent to resin.
[Brief description of the drawings]
FIG. 1 is a GPC chart of ( tertiary) butylated bisphenol A type epoxy resin obtained in Reference Example 1 , wherein elution time (min), response amount (mV), elution time (min) and logarithm of molecular weight ( LogM) was blotted at the same time.
FIG. 2 is an infrared absorption spectrum chart of the ( tertiary) butylated bisphenol A type epoxy resin obtained in Reference Example 1 , wherein the vertical axis represents the absorption intensity and the horizontal axis represents the absorption wavelength.

Claims (1)

(Tertiary) butylation represented by the following general formula (1), having an epoxy equivalent of 180 to 2,000 g / eq , and soluble in an aliphatic solvent having a flash point of 40 ° C. or higher A curable composition for anticorrosive paints, comprising an epoxy resin containing 50 to 100% by weight of a bisphenol A type epoxy resin and an amine curing agent .

(Wherein n ≧ 0, m ≧ 0, R ₁ represents a (tertiary) butyl group , 1 ≦ (a + a ′) ≦ 4, R ₂ is a (tertiary) butyl group or a hydrogen atom, ≦ (b + b ′) ≦ 4, X represents a —CH (CH ₃ ) ₂ — group )

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