JP4094381B2 - Grinding stone resin composition, grinding wheel manufacturing method using the grinding wheel resin composition, and grinding wheel using the grinding wheel resin composition - Google Patents

Description

（一般式（１）中、Ｘ¹は、それぞれ独立に２個〜３個のカルボン酸基を有する多価カルボン酸から誘導された有機残基である。一般式（１）中、ｎは１又は２であり、Ｘ¹が２個のカルボン酸基を有する場合にはｎは１となり、Ｘ¹が３個のカルボン酸基を有する場合にはｎは２となる。一般式（１）中、Ｙ¹は、アルキル基、アリル基、またはメタリル基を表す。ただし、化合物（Ａ）１分子中に存在するＹ¹の少なくとも１つは、アリル基またはメタリル基でなければならない。）
【００１８】
一般式（２）
【００１９】
【化１０】

（一般式（２）中、Ｘ²は、それぞれ独立に２個〜３個のカルボン酸基を有する多価カルボン酸から誘導された有機残基である。一般式（２）中、ｍは１又は２であり、Ｘ²が２個のカルボン酸基を有する場合にはｍは１となり、Ｘ²が３個のカルボン酸基を有する場合にはｍは２となる。一般式（２）中、Ｙ²はそれぞれ独立に２個〜６個の水酸基を有する炭素数２〜２０の多価アルコールから誘導された有機残基を表す。ただし、Ｙ²はエステル結合によって、さらに上記一般式（１）を末端基とし、上記一般式（２）を繰り返し単位とする分岐構造を有することができる。）
【００２０】
また本発明（ＩＩ）は、本発明（Ｉ）の砥石用樹脂組成物に砥粒を混合した後にラジカル重合開始剤を用いて硬化させることを特徴とする砥石の製造方法である。
【００２１】
さらにまた本発明（ＩＩＩ）は、本発明（ＩＩ）の砥石の製造方法で製造されたことを特徴とする砥石である。
【００２２】
さらに本発明は例えば以下の事項からなる。
〔１〕 以下に示す（Ａ）及び（Ｂ）を含むことを特徴とする砥石用樹脂組成物。
（Ａ）一般式（１）で表される基の少なくとも一種以上を末端基として有し、且つ一般式（２）で表される基を繰り返し単位として有する化合物（以下「化合物（Ａ）」とも記す。）
（Ｂ）不飽和ポリエステル樹脂及び／又はビニルエステル樹脂（以下「化合物（Ｂ）」とも記す。）
【００２３】
一般式（１）
【化１１】

（一般式（１）中、Ｘ¹は、それぞれ独立に２個〜３個のカルボン酸基を有する多価カルボン酸から誘導された有機残基である。一般式（１）中、ｎは１又は２であり、Ｘ¹が２個のカルボン酸基を有する場合にはｎは１となり、Ｘ¹が３個のカルボン酸基を有する場合にはｎは２となる。一般式（１）中、Ｙ¹は、アルキル基、アリル基、またはメタリル基を表す。ただし、化合物（Ａ）１分子中に存在するＹ¹の少なくとも１つは、アリル基またはメタリル基でなければならない。）
【００２４】
一般式（２）
【化１２】

（一般式（２）中、Ｘ²は、それぞれ独立に２個〜３個のカルボン酸基を有する多価カルボン酸から誘導された有機残基である。一般式（２）中、ｍは１又は２であり、Ｘ²が２個のカルボン酸基を有する場合にはｍは１となり、Ｘ²が３個のカルボン酸基を有する場合にはｍは２となる。一般式（２）中、Ｙ²はそれぞれ独立に２個〜６個の水酸基を有する炭素数２〜２０の多価アルコールから誘導された有機残基を表す。ただし、Ｙ²はエステル結合によって、さらに上記一般式（１）を末端基とし、上記一般式（２）を繰り返し単位とする分岐構造を有することができる。）
【００２５】
〔２〕 以下に示す（Ａ）及び（Ｂ）に加え、さらに（Ｃ）重合性を有する反応性希釈剤を含むことを特徴とする砥石用樹脂組成物。
（Ａ）一般式（１）で表される基の少なくとも一種以上を末端基として有し、且つ一般式（２）で表される基を繰り返し単位として有する化合物（以下「化合物（Ａ）」とも記す。）
（Ｂ）不飽和ポリエステル樹脂及び／又はビニルエステル樹脂（以下「化合物（Ｂ）」とも記す。）
【００２６】
一般式（１）
【化１３】

（一般式（１）中、Ｘ¹は、それぞれ独立に２個〜３個のカルボン酸基を有する多価カルボン酸から誘導された有機残基である。一般式（１）中、ｎは１又は２であり、Ｘ¹が２個のカルボン酸基を有する場合にはｎは１となり、Ｘ¹が３個のカルボン酸基を有する場合にはｎは２となる。一般式（１）中、Ｙ¹は、アルキル基、アリル基、またはメタリル基を表す。ただし、化合物（Ａ）１分子中に存在するＹ¹の少なくとも１つは、アリル基またはメタリル基でなければならない。）
【００２７】
一般式（２）
【化１４】

（一般式（２）中、Ｘ²は、それぞれ独立に２個〜３個のカルボン酸基を有する多価カルボン酸から誘導された有機残基である。一般式（２）中、ｍは１又は２であり、Ｘ²が２個のカルボン酸基を有する場合にはｍは１となり、Ｘ²が３個のカルボン酸基を有する場合にはｍは２となる。一般式（２）中、Ｙ²はそれぞれ独立に２個〜６個の水酸基を有する炭素数２〜２０の多価アルコールから誘導された有機残基を表す。ただし、Ｙ²はエステル結合によって、さらに上記一般式（１）を末端基とし、上記一般式（２）を繰り返し単位とする分岐構造を有することができる。）
【００２８】
〔３〕 以下に示す（Ａ）を１質量％〜９９質量％、及び（Ｂ）を１質量％〜９９質量％の範囲で含むことを特徴とする〔１〕又は〔２〕のいずれかに記載の砥石用樹脂組成物。
（Ａ）下記一般式（１）で表される基の少なくとも一種以上を末端基として有し、下記一般式（２）で表される基を繰り返し単位として有する化合物
（Ｂ）不飽和ポリエステル樹脂及び／又はビニルエステル樹脂
【００２９】
一般式（１）
【化１５】

（一般式（１）中、Ｘ¹は、それぞれ独立に２個〜３個のカルボン酸基を有する多価カルボン酸から誘導された有機残基である。一般式（１）中、ｎは１又は２であり、Ｘ¹が２個のカルボン酸基を有する場合にはｎは１となり、Ｘ¹が３個のカルボン酸基を有する場合にはｎは２となる。一般式（１）中、Ｙ¹は、アルキル基、アリル基、またはメタリル基を表す。ただし、化合物（Ａ）１分子中に存在するＹ¹の少なくとも１つは、アリル基またはメタリル基でなければならない。）
【００３０】
一般式（２）
【化１６】

（一般式（２）中、Ｘ²は、それぞれ独立に２個〜３個のカルボン酸基を有する多価カルボン酸から誘導された有機残基である。一般式（２）中、ｍは１又は２であり、Ｘ²が２個のカルボン酸基を有する場合にはｍは１となり、Ｘ²が３個のカルボン酸基を有する場合にはｍは２となる。一般式（２）中、Ｙ²はそれぞれ独立に２個〜６個の水酸基を有する炭素数２〜２０の多価アルコールから誘導された有機残基を表す。ただし、Ｙ²はエステル結合によって、さらに上記一般式（１）を末端基とし、上記一般式（２）を繰り返し単位とする分岐構造を有することができる。）
【００３１】
〔４〕 以下に示す（Ａ）を１質量％〜９９質量％、（Ｂ）を１質量％〜９９質量％、及び（Ｃ）を０質量％〜５０質量％の範囲で含むことを特徴とする〔１〕〜〔３〕のいずれかに記載の砥石用樹脂組成物。
（Ａ）下記一般式（１）で表される基の少なくとも一種以上を末端基として有し、下記一般式（２）で表される基を繰り返し単位として有する化合物
（Ｂ）不飽和ポリエステル樹脂及び／又はビニルエステル樹脂
（Ｃ）重合性を有する反応性希釈剤
【００３２】
一般式（１）
【化１７】

（一般式（１）中、Ｘ¹は、それぞれ独立に２個〜３個のカルボン酸基を有する多価カルボン酸から誘導された有機残基である。一般式（１）中、ｎは１又は２であり、Ｘ¹が２個のカルボン酸基を有する場合にはｎは１となり、Ｘ¹が３個のカルボン酸基を有する場合にはｎは２となる。一般式（１）中、Ｙ¹は、アルキル基、アリル基、またはメタリル基を表す。ただし、化合物（Ａ）１分子中に存在するＹ¹の少なくとも１つは、アリル基またはメタリル基でなければならない。）
【００３３】
一般式（２）
【化１８】

（一般式（２）中、Ｘ²は、それぞれ独立に２個〜３個のカルボン酸基を有する多価カルボン酸から誘導された有機残基である。一般式（２）中、ｍは１又は２であり、Ｘ²が２個のカルボン酸基を有する場合にはｍは１となり、Ｘ²が３個のカルボン酸基を有する場合にはｍは２となる。一般式（２）中、Ｙ²はそれぞれ独立に２個〜６個の水酸基を有する炭素数２〜２０の多価アルコールから誘導された有機残基を表す。ただし、Ｙ²はエステル結合によって、さらに上記一般式（１）を末端基とし、上記一般式（２）を繰り返し単位とする分岐構造を有することができる。）
【００３４】
〔５〕 一般式（１）中のＸ¹または一般式（２）中のＸ²の少なくとも１つがイタコン酸またはマレイン酸から選ばれた少なくとも一種の化合物より誘導された有機残基であることを特徴とする〔１〕〜〔４〕のいずれかに記載の砥石用樹脂組成物。
【００３５】
〔６〕 （Ｃ）重合性を有する反応性希釈剤が、ビニル化合物、アリル化合物、及びこれらの混合物からなる群から選ばれる一種であることを特徴とする〔２〕〜〔５〕のいずれかに記載の砥石用樹脂組成物。
【００３６】
〔７〕 〔１〕〜〔６〕のいずれかに記載の砥石用樹脂組成物に砥粒を混合した後にラジカル重合開始剤を用いて硬化させることを特徴とする砥石の製造方法。
【００３７】
〔８〕 〔１〕〜〔６〕のいずれかに記載の砥石用樹脂組成物に砥粒と気孔材及び／又は発泡剤を混合した後にラジカル重合開始剤を用いて硬化させることを特徴とする砥石の製造方法。
【００３８】
〔９〕 砥粒の含有量を砥石全体の質量に対して１０質量％〜８０質量％の範囲になるように調整した後にラジカル重合開始剤を用いて硬化させることを特徴とする〔７〕又は〔８〕のいずれかに記載の砥石の製造方法。
【００３９】
〔１０〕 砥粒がアルミナ質砥粒、炭化けい素質砥粒及び立方晶窒化ほう素質砥粒、ダイヤモンド質砥粒からなる群から選ばれる一種以上であることを特徴とする〔７〕〜〔９〕のいずれかに記載の砥石の製造方法。
【００４０】
〔１１〕 気孔材の直径が５０μｍ〜３００μｍの範囲であることを特徴とする〔８〕〜〔１０〕のいずれかに記載の砥石の製造方法。
【００４１】
〔１２〕 発泡剤がアゾ化合物、ニトロソ化合物、スルホニルヒドラジド化合物及びこれらの二種以上の混合物からなる群から選ばれる一種であることを特徴とする〔８〕〜〔１１〕のいずれかに記載の砥石の製造方法。
【００４２】
〔１３〕 ラジカル重合開始剤が、ｔ−ブチルパーオキシベンゾエート、クメンハイドロパーオキサイド及びこれらの混合物からなる群から選ばれる一種であることを特徴とする〔７〕〜〔１２〕のいずれかに記載の砥石の製造方法。
【００４３】
〔１４〕 ラジカル重合開始剤にレドックス促進剤を添加した後に硬化させることを特徴とする〔７〕〜〔１３〕のいずれかに記載の砥石の製造方法。
【００４４】
〔１５〕 レドックス促進剤がコバルトのカルボン酸塩、銅のカルボン酸塩及びこれらの混合物からなる群から選ばれる一種であることを特徴とする〔１４〕に記載の砥石の製造方法。
【００４５】
〔１６〕 レドックス促進剤がナフテン酸コバルトであることを特徴とする〔１４〕に記載の砥石の製造方法。
【００４６】
〔１７〕 常温にて硬化させることを特徴とする〔７〕〜〔１６〕のいずれかに記載の砥石の製造方法。
【００４７】
〔１８〕 〔７〕〜〔１７〕のいずれかに記載の製造方法で製造されたことを特徴とする砥石。
【００４８】
〔１９〕 〔７〕〜〔１７〕のいずれかに記載の製造方法で製造されたことを特徴とするステンレス合金、アルミニウム金属及びその合金、またはニッケル合金の研削用及び／又は研磨用の砥石。
【００４９】
【発明の実施の形態】
以下、本発明についてより詳しく説明する。
まず、本発明（Ｉ）について説明する。本発明（Ｉ）は、以下に示す（Ａ）及び（Ｂ）を含むことを特徴とする砥石用樹脂組成物である。
（Ａ）一般式（１）で表される基の少なくとも一種以上を末端基として有し、且つ一般式（２）で表される基を繰り返し単位として有する化合物
（Ｂ）不飽和ポリエステル樹脂及び／又はビニルエステル樹脂
【００５０】
一般式（１）
【００５１】
【化１９】

（一般式（１）中、Ｘ¹は、それぞれ独立に２個〜３個のカルボン酸基を有する多価カルボン酸から誘導された有機残基である。一般式（１）中、ｎは１又は２であり、Ｘ¹が２個のカルボン酸基を有する場合にはｎは１となり、Ｘ¹が３個のカルボン酸基を有する場合にはｎは２となる。一般式（１）中、Ｙ¹は、アルキル基、アリル基、またはメタリル基を表す。ただし、化合物（Ａ）１分子中に存在するＹ¹の少なくとも１つは、アリル基またはメタリル基でなければならない。）
一般式（２）
【００５２】
【化２０】

（一般式（２）中、Ｘ²は、それぞれ独立に２個〜３個のカルボン酸基を有する多価カルボン酸から誘導された有機残基である。一般式（２）中、ｍは１又は２であり、Ｘ²が２個のカルボン酸基を有する場合にはｍは１となり、Ｘ²が３個のカルボン酸基を有する場合にはｍは２となる。一般式（２）中、Ｙ²はそれぞれ独立に２個〜６個の水酸基を有する炭素数２〜２０の多価アルコールから誘導された有機残基を表す。ただし、Ｙ²はエステル結合によって、さらに上記一般式（１）を末端基とし、上記一般式（２）を繰り返し単位とする分岐構造を有することができる。）
【００５３】
本発明における『砥石』とは、各種砥粒を樹脂により結合させ固めたものをいう。また、本発明における砥石は、往復動、回転動、及び／又は往復動と回転動とを組み合わせた動き等をさせながら、被削材と接触させることにより被削材を削る機能を有するものである。さらに、本発明における砥石の形状は特に限定するものではなく、円盤、円筒、皿形、椀形、角形と様々な形状のものを含み、局所的に砥粒の成分や粒径や異なるような多層構造のものも含む。
【００５４】
本発明（Ｉ）に用いられる （Ａ）一般式（１）で表される基の少なくとも一種以上を末端基として有し、且つ一般式（２）で表される基を繰り返し単位として有する化合物において、一般式（１）中のＸ¹及び一般式（２）のＸ²は、それぞれ独立に２個〜３個のカルボン酸基を有する多価カルボン酸から誘導された有機残基である。
【００５５】
２個のカルボン酸基を有する多価カルボン酸の具体例としては、テレフタル酸、イソフタル酸、フタル酸、マレイン酸、フマル酸、イタコン酸、シトラコン酸、アジピン酸、マロン酸、コハク酸、グルタル酸、セバシン酸、１，３−シクロヘキサンジカルボン酸、１，４−シクロヘキサンジカルボン酸、１，４−ナフタリンジカルボン酸、１，５−ナフタリンジカルボン酸、２，７−ナフタリンジカルボン酸、ジフェニル−ｍ，ｍ’−ジカルボン酸、ジフェニル−ｐ，ｐ’−ジカルボン酸、ベンゾフェノン−４，４’−ジカルボン酸、ｐ−フェニレンジ酢酸、ｐ−カルボキシフェニル酢酸、メチルテレフタル酸、テトラクロルフタル酸、無水エンディック酸、無水クロレンド酸等が挙げられる。
【００５６】
また、３個のカルボン酸基を有する多価カルボン酸の具体例としては、１，２，４−トリメリット酸が挙げられる。いうまでもなく、これらの具体例に限定されるものではない。
【００５７】
例えば、Ｘ¹及びＸ²がテレフタル酸から誘導される有機残基であった場合、一般式（１）及び一般式（２）はそれぞれ構造式−１及び構造式−２で表すことができる。
構造式−１
【００５８】
【化２１】

構造式−２
【００５９】
【化２２】

【００６０】
砥石の耐熱性を高めるためには、ベンゼン環を有する多価カルボン酸、内部不飽和結合を有する多価カルボン酸、及び／又は３個のカルボン酸基を有する多価カルボン酸が好ましい。より好ましくは、テレフタル酸、イソフタル酸、イタコン酸又はマレイン酸である。
【００６１】
一般式（１）中のＸ¹及び一般式（２）のＸ²は、それぞれ独立に２個〜３個のカルボン酸基を有する多価カルボン酸から誘導された有機残基である。例えば、Ｘ¹の全てが同一の構造を有する多価カルボン酸から誘導される有機残基であっても、全て異なる構造を有する多価カルボン酸から誘導される有機残基であっても、さらに、いくらかは同一の構造を有する多価カルボン酸から誘導される有機残基であり、他のいくらかは別の種類の構造を有する多価カルボン酸から誘導される有機残基であるといった、いわゆる混合構造であってもいっこうに差し支えない。さらにその混合構造も全部が完全にランダムであっても、一部は繰り返してもかまわない。
【００６２】
Ｘ²についても同様に、Ｘ²の全てが同一の構造を有する多価カルボン酸から誘導される有機残基であっても、全て異なる構造を有する多価カルボン酸から誘導される有機残基であっても、さらに、いくらかは同一の構造を有する多価カルボン酸から誘導される有機残基であり、他のいくらかは別の種類の構造を有する多価カルボン酸から誘導される有機残基であるといった混合構造であってもいっこうに差し支えない。さらにその混合構造も全部が完全にランダムであっても、一部は繰り返してもかまわない。
【００６３】
一般式（１）中、Ｙ¹は、アルキル基、アリル基、またはメタリル基を表す。ただし、化合物（Ａ）中に存在するＹ¹の少なくとも１つは、アリル基またはメタリル基でなければならない。これは化合物（Ａ）中に存在する少なくとも１つのＹ¹はアリル基またはメタリル基であることが必須条件であり、例えば、化合物（Ａ）中に存在する全てのＹ¹がアルキル基のものは一般式（１）には該当しないことを意味する。
【００６４】
一般式（２）中、Ｙ²はそれぞれ独立に２個〜６個の水酸基を有する炭素数２〜炭素数２０の多価アルコールから誘導された有機残基を表す。
【００６５】
２個の水酸基を有する多価アルコールの具体例としては、エチレングリコール、プロピレングリコール、１，３−プロパンジオール、１，４−ブタンジオール、１，３−ブタンジオール、１，２−ブタンジオール、ネオペンチルグリコール、１，５−ペンタンジオール、３−メチル−１，５−ペンタンジオール、１，６−ヘキサンジオール、１，３−シクロヘキサンジオール、１，４−シクロヘキサンジオール、１，１−シクロヘキサンジメタノール、１，２−シクロヘキサンジメタノール、１，３−シクロヘキサンジメタノール、２−メチルシクロヘキサン−１，１−ジメタノール、６−メチル−３−シクロヘキサン−１，１−ジメタノール、１，４−シクロヘキサンジメタノール、ｐ−キシレングリコール、ｍ−キシレングリコール、スチレングリコール、トリシクロデカンジメタノール、２−メチルシクロヘキサンジメタノール、ビスフェノールＡ・エチレンオキサイド付加物、ビスフェノールＡ・プロピレンオキサイド付加物等が挙げられる。更にジエチレングリコール、ジプロピレングリコール、トリエチレングリコール、ポリエチレングリコール等の主鎖にエーテル基を含んだ２価のアルコール等も挙げられる。
【００６６】
また、３個以上の水酸基を有する多価アルコールの具体例としては、グリセリン、トリメチロールプロパン、トリメチロールエタン、ペンタエリスリトール、ジペンタエリスリトール、ソルビトール等が挙げられる。いうまでもなく、これらの具体例に限定されるものではない。
【００６７】
例えば、Ｙ²がエチレングリコールから誘導される有機残基であった場合、一般式（２）は構造式−３で表すことができる。
構造式−３
【００６８】
【化２３】

（構造式−３中、Ｘ²は、それぞれ独立に２個〜３個のカルボン酸基を有する多価カルボン酸から誘導された有機残基である。構造式−３中、ｍは１又は２であり、Ｘ²が２個のカルボン酸基を有する場合にはｍは１となり、Ｘ²が３個のカルボン酸基を有する場合にはｍは２となる。）
【００６９】
一般式（２）中、Ｙ²はそれぞれ独立に２個〜６個の水酸基を有する炭素数２〜炭素数２０の多価アルコールから誘導された有機残基を表す。例えば、Ｙ²の全てが同一の構造を有する多価アルコールから誘導される有機残基であっても、全て異なる構造を有する多価アルコールから誘導される有機残基であっても、さらに、いくらかは同一の構造を有する多価アルコールから誘導される有機残基であり、他のいくらかは別の種類の構造を有する多価アルコールから誘導される有機残基であるといった混合構造であってもいっこうに差し支えない。さらにその混合構造も全部が完全にランダムであっても、一部は繰り返してもかまわない。
【００７０】
さらに、Ｙ²はエステル結合によって、さらに一般式（１）を末端基とし、一般式（２）を繰り返し単位とする分岐構造を有することができる。即ち、例えばＹ²に３個の水酸基を有する多価アルコールの一例であるトリメチロールプロパンから誘導される有機残基が存在した場合、本発明（Ｉ）の組成物中に含まれる化合物（Ａ）は構造式−４で表される部分構造を有することができる。
構造式−４
【００７１】
【化２４】

（構造式−４中、Ｘ³、Ｘ⁴、Ｘ⁵は、それぞれ独立に２個〜３個のカルボン酸基を有する多価カルボン酸から誘導された有機残基である。構造式−４中、ｓ、ｔ、ｕは１又は２であり、Ｘ³、Ｘ⁴、Ｘ⁵が２個のカルボン酸基を有する場合にはｓ、ｔ、ｕは１となり、Ｘ³、Ｘ⁴、Ｘ⁵が３個のカルボン酸基を有する場合にはｓ、ｔ、ｕは２となる。）
【００７２】
本発明（Ｉ）に用いられる不飽和ポリエステル樹脂とは、多価アルコールと不飽和結合を有する多塩基酸及び／又はその無水物（及び必要に応じて飽和多塩基酸）とのエステル化反応による縮合生成物を、必要に応じてスチレンのような重合性不飽和化合物に溶解したものをいう。ただし、化合物（Ａ）として定義した特定の構造に該当するものは、本明細書中では不飽和ポリエステル樹脂に含めないこととする。
【００７３】
不飽和ポリエステル樹脂の具体的例としては、例えば、「ポリエステル樹脂ハンドブック」（日刊工業新聞社 １９８８年発行）、「塗料用語辞典」（色材協会編 １９９３年発行）などに記載されている樹脂を指し、公知の方法で製造することができる。
【００７４】
不飽和結合を有する多塩基酸またはその無水物の具体例としては、フマル酸、無水マレイン酸、マレイン酸、イタコン酸等を挙げることができる。また、必要に応じて、無水フタル酸、イソフタル酸、テレフタル酸、テトラヒドロフタル酸、アジピン酸等の活性不飽和結合を有していない飽和多塩基酸またはその無水物、安息香酸、アビエチン酸、ジシクロペンテニルマレイン酸のハーフエステルのごときモノカルボン酸を用いることができる。
【００７５】
また、多価アルコールの具体例としては、エチレングリコール、プロピレングリコール、ジエチレングリコール、ジプロピレングリコール、１，２−ブタンジオール、１，３−ブタンジオール、１，５−ペンタンジオール、１，６−ヘキサンジオール、２−メチル−１，３−プロパンジオール、２，２−ジメチル−１，３−プロパンジオール、シクロヘキサン−１，４−ジメタノール、ビスフェノールＡのエチレンオキサイド付加物、ビスフェノールＡのプロピレンオキサイド付加物等の多価アルコールが挙げられる。
【００７６】
本発明（Ｉ）に用いられるビニルエステル樹脂はエポキシ（メタ）アクリレートとも呼ばれ、一般にエポキシ樹脂に代表されるエポキシ基を有する化合物と（メタ）アクリル酸などの重合性不飽和基を有するカルボキシル化合物のカルボキシル基との開環反応により生成する重合性不飽和基を有する樹脂、またはカルボキシル基を有する化合物とグリシジル（メタ）アクリレート等の分子内にエポキシ基を持つ重合性不飽和化合物のエポキシ基との開環反応により生成する重合性不飽和基を有する樹脂である。具体的には、例えば、「ポリエステル樹脂ハンドブック」（日刊工業新聞社 １９８８年発行）、「塗料用語辞典」（色材協会編１９９３年発行）などに記載されている樹脂を指し、公知の方法により製造することができる。
【００７７】
ビニルエステル樹脂の原料となるエポキシ樹脂としては、ビスフェノールＡジグリシジルエーテル及びその高分子量同族体、ビスフェノールＡアルキレンオキサイド付加物のグリシジルエーテル、ビスフェノールＦジグリシジルエーテル及びその高分子量同族体、ビスフェノールＦアルキレンオキサイド付加物のグリシジルエーテル、ノボラック型ポリグリシジルエーテル類等が挙げられる。
【００７８】
本発明（Ｉ）の（Ｂ）成分は、不飽和ポリエステル樹脂であっても、ビニルエステル樹脂であっても、不飽和ポリエステル樹脂とビニルエステル樹脂の混合物であっても差し支えない。不飽和ポリエステル樹脂は、一種類の不飽和ポリエステル樹脂を使用しても、何種類かの不飽和ポリエステル樹脂を混合して使用することもできる。ビニルエステル樹脂も、一種類のビニルエステル樹脂を使用しても、何種類かのビニルエステル樹脂を混合して使用することもできる。いうまでもなく、一種類及び／又は何種類かの不飽和ポリエステル樹脂と、一種類及び／又は何種類かのビニルエステル樹脂を混合して使用することもできる。
【００７９】
本発明（Ｉ）の砥石用樹脂組成物は、化合物（Ａ）及び化合物（Ｂ）に加えて樹脂組成物の粘度調整や最終的な砥石の物性を制御する等の目的に応じて、さらに（Ｃ）重合性を有する反応性希釈剤（以下「化合物（Ｃ）」とも記す。）を添加することができる。
【００８０】
化合物（Ｃ）の具体例としては、例えばスチレン、ビニルトルエン、ジビニルベンゼン、α−メチルスチレン、メタクリル酸メチル、酢酸ビニル等のビニル化合物や、ジアリルテレフタレート、ジアリルイソフタレート、ジアリルフタレート、トリアリルイソシアヌレート等のアリル化合物を例示することができる。いうまでもなく反応性希釈剤はこれら具体例に限定されるものではない。
【００８１】
中でも好ましく用いられるのはスチレン、ジアリルテレフタレート、及び／又はジアリルイソフタレートであり、特に好ましく用いられるのはスチレンである。
【００８２】
本発明（Ｉ）の砥石用樹脂組成物における化合物（Ａ）、化合物（Ｂ）、及び化合物（Ｃ）の使用割合には特に制限はない。好ましくは、化合物（Ａ）が１質量％〜９９質量％、化合物（Ｂ）が１質量％〜９９質量％、、化合物（Ｃ）が０質量％〜５０質量％の範囲である。
【００８３】
化合物（Ａ）の含有量が少なすぎると砥石の研削抵抗が大きくなり、化合物（Ａ）の含有量が多すぎると原材料コストが割高になる。従って、化合物（Ａ）の含有量は、好ましくは１質量％〜９０質量％、より好ましくは５質量％〜７０質量％、さらに好ましくは１０質量％〜５０質量％である。
【００８４】
同様の理由で、化合物（Ｂ）の含有量は、好ましくは１質量％〜９５質量％、より好ましくは１０質量％〜８０質量％、さらに好ましくは２０質量％〜７０質量％である。
【００８５】
また、化合物（Ｃ）は必要に応じて使用することができるが、含有量が多すぎると砥石の機械的強度が低下する恐れがある。従って、化合物（Ｃ）の含有量は、好ましくは０質量％〜５０質量％、より好ましくは５質量％〜４５質量％、さらに好ましくは１０質量％〜４０質量％である。
【００８６】
なお、化合物（Ａ）、化合物（Ｂ）、及び化合物（Ｃ）各々の質量％の総和は１００質量％であることは言うまでもない。また、後述する砥粒、発泡剤、気孔材等のその他の添加剤はここには含まないことも同様である。
【００８７】
次に本発明（ＩＩ）について説明する。本発明（ＩＩ）は、本発明（Ｉ）の砥石用樹脂組成物に砥粒を混合した後にラジカル重合開始剤を用いて硬化させることを特徴とする砥石の製造方法である。
【００８８】
砥石に用いられる砥粒は特に限定されるものではなく従来公知のものが使用できる。具体的には例えば、アルミナ質砥粒、炭化けい素質砥粒、炭化ほう素質砥粒、立方晶窒化ほう素質砥粒、ダイヤモンド質砥粒等の砥粒を例示することができる。これらの砥粒は単独で使用しても良いが、複数種の砥粒を混合して使用することもできる。好ましくは用いられるのはアルミナ質砥粒、炭化けい素質砥粒、立方晶窒化ほう素質砥粒であり、より好ましくはアルミナ質砥粒である。また、使用する砥粒の粒度も特に限定されるものではなく、小さな砥粒を用いると精度の高い研削が可能になる。
【００８９】
砥石成形体中の砥粒の含有率については特に制限されるものではないが、砥粒含有率が多いと砥石成形体の強度が低くなり、砥粒含有率が低いと砥石として研削する能力が低くなる。砥粒の含有率は、好ましくは１０質量％〜８０質量％、より好ましくは１５質量％〜６０質量％、さらに好ましくは２０質量％〜５０質量％である。
【００９０】
ラジカル重合開始剤としては従来公知のものを使用することができる。具体的には例えば、過酸化ベンゾイル、ジクミルパーオキサイド、ｔ−ブチルハイドロパーオキシド、ジ−ｔ−ブチルパーオキシ−３，３，５−トリメチルシクロヘキサン、メチルエチルケトンパーオキサイド、シクロヘキサノンパーオキサイド、メチルアセトアセテートパーオキサイド、アセチルアセトンパーオキサイド、クメンハイドロパーオキサイド、ベンゾイルパーオキサイド、ｔ−ブチルパーオキシ−２−エチルヘキサノエート、ｔ−ブチルパーオキシベンゾエート等を例示することができ、上記パーオキサイドは混合して使用することもできる。いうまでもなく、ラジカル重合開始剤は上記具体例に限定されるものではなく、分解しラジカルを発生させる化合物であればよい。なお、硬化温度は使用するラジカル重合開始剤の性質により選択されるものであって、熱分解半減期により適宜選択することができる。
【００９１】
本発明（ＩＩ）の砥石の製造方法では、砥粒に加えて気孔材及び／又は発泡剤を混合した後にラジカル重合開始剤を用いて硬化させる製造方法をとることもできる。
【００９２】
研削面の冷却、削り屑等の除去、および砥石の目詰まりを抑制するためには、砥石に気孔が存在する方が好ましい。その気孔を発生させるために気孔材及び／又は発泡剤を添加することができる。
【００９３】
気孔材としては、例えば、無機バルーン及び／又は有機バルーンを例示することができる。無機バルーンとは、例えばシリカ及び／又はアルミナ等の無機材質の殻の中にガスが封入されているものを指し、その殻の厚みや中のガスについては特に限定されるものではない。有機バルーンとは、例えばポリスチレン、ポリエチレン、ポリプロピレン等の有機材質の殻の中にガスが封入されているものを指し、その殻の厚みや中のガスについては特に限定されるものではない。具体的には、ガラスバルーン、シラスバルーン、シリカバルーン、カーボンバルーン、フェノール樹脂バルーン、塩化ビニリデン樹脂バルーン、ポリスチレン樹脂バルーン、ポリエチレン樹脂バルーン、ポリプロピレン樹脂バルーン、ジルコニアバルーン、アルミナバルーン、フライアッシュバルーン、パーライトバルーン等を例示することができる。
【００９４】
気孔材の大きさは研削性能に影響を及ぼすため、適度な大きさの気孔材を選定することが好ましい。バルーンの直径は、好ましくは５μｍ〜１０００μｍ、より好ましくは１０μｍ〜５００μｍ、さらに好ましくは５０μｍ〜３００μｍである。
【００９５】
また発泡剤としては、本発明（Ｉ）の砥石用樹脂組成物が硬化するときに発生する熱によって分解し、気体を発生するものであれば特に限定されるものではなく、該当する化合物群の例としてはアゾ化合物、ニトロソ化合物、スルホニルヒドラジド化合物等が挙げられる。
【００９６】
具体的には、例えばアゾジカルボンアミド、アゾビスイソブチロニトリル、Ｎ，Ｎ’−ジニトロソペンタメチレンテトラミン、ｐ−トルエンスルホニルヒドラジン、４，４’−オキシビス（ベンゼンスルホニルヒドラジド）等を例示することができる。これらは、単独で使用してもよいが、混合して用いることもできる。好ましく用いられるものは、Ｎ，Ｎ’−ジニトロソペンタメチレンテトラミン、ｐ−トルエンスルホニルヒドラジンである。
【００９７】
その他の添加剤としては、硬化前の組成物の粘度を調整する目的で、氷晶石、無機塩化物、無機硫化物等を添加することができる。これらの添加物により樹脂中の砥粒をより均一に分散させる効果がある。
【００９８】
本発明（ＩＩ）の砥石の製造方法においては、ラジカル重合開始剤にレドックス促進剤を添加した後に硬化させる製造方法をとることもできる。
【００９９】
レドックス促進剤としては、ナフテン酸コバルト、オクチル酸コバルト、ステアリン酸コバルト、ナフテン酸銅等を例示することができ、好ましく用いられるものは、ナフテン酸銅である。
【０１００】
レドックス促進剤と共に用いる過酸化物としては、メチルエチルケトンパーオキサイド、シクロヘキサノンパーオキサイド、メチルアセトアセテートパーオキサイド、アセチルアセトンパーオキサイド、クメンハイドロパーオキサイド、ベンゾイルパーオキサイド、ｔ−ブチルパーオキシ−２−エチルヘキサノエート、ｔ−ブチルパーオキシベンゾエート等を例示することができ、上記パーオキサイドは混合して使用することもできる。好ましく用いられるのは、クメンハイドロパーオキサイド及び／又はｔ−ブチルパーオキシベンゾエートである。
【０１０１】
さらに、硬化を速めるために、上記過酸化物とレドックス促進剤に助促進剤を加えることもできる。助促進剤としては、Ｎ，Ｎ’−ジメチルアセトアセタミド、アセチルアセトン、ジメドン、ジベンゾイルメタン、アセチルシクロペンタン、アセト酢酸メチル、アセト酢酸エチル、アセチルブチロラクトン、ジメチルアニリン等を例示することができる。
【０１０２】
本発明（ＩＩ）の砥石の製造方法では、その砥石用樹脂組成物の硬化を常温にて行い、砥石を製造することもできる。ここでいう「硬化を常温で行う」とは、人為的に極端に加熱することなく硬化することを意味する。また、ここで言う「人為的に極端に加熱する」とは、作業者の意志で熱エネルギー等を供給し、硬化前の材料を１００℃以上にすることを意味する。従って、樹脂原料が硬化するときに発生する熱（いわゆる硬化発熱）により１００℃以上になったとしても「人為的に極端に加熱する」ことには該当しない。
【０１０３】
また、例えば、２５℃に温度調節した場所に放置して硬化させてもよいし、地球上の自然環境の影響で例えば−２０℃〜６０℃の範囲で温度が変動する場所に放置して硬化させてもよい。さらには、硬化を速める目的で例えば５０℃に温度調節した場所に放置して硬化させてもよいし、１０℃に温度調節した場所に放置して硬化させてもよい。ただしあまり温度を高くすると硬化が速すぎるため、硬化反応が暴走する危険性があり好ましくない。また温度が低すぎると硬化に時間がかかるため経済的ではない。
【０１０４】
さらに、ここでいう「硬化」とは、樹脂組成物が所望の型から離型できる程度に重合反応がすすんだ状態のことを意味する。したがって、重合性を有する官能基の反応割合は特に問題としない。
【０１０５】
常温硬化は、通常、所望の形状の鋳型中で放置することで硬化させるが、砥石成型物の形状を安定させるために、圧力を加えて硬化させることもできる。鋳型は、砥石として所望の形状をした型であれば特に限定されるものではないが、樹脂が硬化するときの発熱により鋳型が大きく変形しない材質が好ましい。通常、機械的強度と耐熱性とを有する、ステンレス等の金属材料やＦｉｂｅｒｇｌａｓｓ Ｒｅｉｎｆｏｒｃｅｄ Ｐｌａｓｔｉｃ等の樹脂材料を用いることができる。
【０１０６】
硬化後の砥石は、樹脂の重合度を高めるために必要に応じて熱処理（アフターキュア）を行ってもよい。アフターキュアは鋳型から砥石を取り出して行ってもよいし、鋳型に入れたまま行ってもよい。アフターキュアの温度は用いた樹脂の組成にもよるが通常１００℃〜２００℃の範囲で、好ましくは１１０℃〜１８０℃の範囲、さらに好ましくは１２０℃〜１６０℃の範囲である。
【０１０７】
最後に本発明（ＩＩＩ）について説明する。本発明（ＩＩＩ）は、本発明（ＩＩ）の砥石の製造方法で製造されたことを特徴とする砥石である。
【０１０８】
本発明（ＩＩＩ）による砥石は、幅広い材質の材料に対して研削または研磨できる性能を有する。中でも好ましくは、ステンレス合金、アルミニウム金属及びその合金、またはニッケル合金等の研削用及び研磨用に好適に使用することができる。特に、研削時の発熱が従来の砥石に比べて低いのでより精密な研削及び研磨が可能である。
【０１０９】
【実施例】
以下、実施例により本発明を更に詳しく説明するが、本発明の主旨を逸脱しない限り本発明はこれらの実施例に限定されるものではない。
【０１１０】
（合成例１）
蒸留装置のついた２リットルの三つ口フラスコにジアリルテレフタレートを７４０ｇ、ジメチルマレートを４３２ｇ、プロピレングリコールを４１９ｇ、ジブチル錫オキサイド１．３ｇを仕込んで窒素気流下で１７０℃に加熱し、生成してくるアルコールを留去した。留去したアルコールが約３４０ｇになったところで反応系内を徐々に６６５０Ｐａまで減圧にし、アルコールの留出速度を速めた。留出液が殆ど出なくなったところで、反応系内を５３０Ｐａにし、さらに１時間反応させて、反応物を冷却した。得られた反応物に、スチレン含有量として３０質量％となるようにスチレンを添加した。これを以下原料（Ａ）とする。
【０１１１】
（合成例２）
蒸留装置のついた２リットルの三つ口フラスコにジアリルテレフタレートを７４０ｇ、ジメチルイタコネートを４７５ｇ、プロピレングリコールを４１９ｇ、ジブチル錫オキサイド１．３ｇを仕込んで窒素気流下で１７０℃に加熱し、生成してくるアルコールを留去した。留去したアルコールが約３４０ｇになったところで反応系内を徐々に６６５０Ｐａまで減圧にし、アルコールの留出速度を速めた。留出液が殆ど出なくなったところで、反応系内を５３０Ｐａにし、さらに１時間反応させて、反応物を冷却した。得られた反応物に、スチレン含有量として３０質量％となるようにスチレンを添加した。これを以下原料（Ｂ）とする。
【０１１２】
（実施例１）
ビニルエステル樹脂（昭和高分子製、Ｈ６００）７０６ｇ、スチレンモノマー２６ｇ、原料（Ａ）１８５ｇ、ナフテン酸コバルト（コバルト含有量６％）１９ｇ、ｐ−トルエンスルホニルヒドラジド３８ｇ、粒径２００μｍ〜３００μｍのアルミナ質砥粒（日本軽金属製、ＷＡ Ｆ６０）２５３０ｇ、気孔材（日本フィライト製、フィライト（登録商標）ＦＧ）７９ｇ、氷晶石２５０ｇ、過酸化物硬化剤（化薬アクゾ製、３２８Ｅ）４９ｇを短時間に均一分散混合できるプロペラ回転機で約６０秒攪拌して均一にし、外径２５５ｍｍφ×厚み３０ｍｍ×穴径３５ｍｍφの砥石注型用金型に充填した。これを室温２０±５℃で放置したところ約１５分程度で発熱が認められ、次第に硬化した。硬化終了後、さらに１３０℃にて１時間アフターキュアして実施例１の研削砥石を得た。
【０１１３】
（実施例２）
ビニルエステル樹脂（昭和高分子製、Ｈ６００）４２４ｇ、不飽和ポリエステル樹脂（三井化学製、Ｒ−１３０Ｂ）２８２ｇ、スチレンモノマー２６ｇ、原料（Ａ）１８５ｇ、ナフテン酸コバルト（コバルト含有量６％）１９ｇ、ｐ−トルエンスルホニルヒドラジド３８ｇ、粒径２００μｍ〜３００μｍのアルミナ質砥粒（日本軽金属製、ＷＡ Ｆ６０）２５３０ｇ、気孔材（日本フィライト製、フィライト（登録商標）ＦＧ）７９ｇ、氷晶石２５０ｇ、過酸化物硬化剤（化薬アクゾ製、３２８Ｅ）４９ｇを短時間に均一分散混合できるプロペラ回転機で約６０秒攪拌して均一にし、外径２５５ｍｍφ×厚み３０ｍｍ×穴径３５ｍｍφの砥石注型用金型に充填した。これを室温２０±５℃で放置したところ約２０分程度で発熱が認められ、次第に硬化した。硬化終了後、さらに１３０℃にて１時間アフターキュアして実施例２の研削砥石を得た。
【０１１４】
（実施例３）
ビニルエステル樹脂（昭和高分子製、Ｈ６００）２８２ｇ、不飽和ポリエステル樹脂（三井化学製、Ｒ−１３０Ｂ）４２４ｇ、スチレンモノマー２６ｇ、原料（Ａ）１８５ｇ、ナフテン酸コバルト（コバルト含有量６％）１９ｇ、ｐ−トルエンスルホニルヒドラジド３８ｇ、粒径２００μｍ〜３００μｍのアルミナ質砥粒（日本軽金属製、ＷＡ Ｆ６０）２５３０ｇ、気孔材（日本フィライト製、フィライト（登録商標）ＦＧ）７９ｇ、氷晶石２５０ｇ、過酸化物硬化剤（化薬アクゾ製、３２８Ｅ）４９ｇを短時間に均一分散混合できるプロペラ回転機で約６０秒攪拌して均一にし、外径２５５ｍｍφ×厚み３０ｍｍ×穴径３５ｍｍφの砥石注型用金型に充填した。これを室温２０±５℃で放置したところ約２０分程度で発熱が認められ、次第に硬化した。硬化終了後、さらに１３０℃にて１時間アフターキュアして実施例３の研削砥石を得た。
【０１１５】
（実施例４）
不飽和ポリエステル樹脂（三井化学製、Ｒ−１３０Ｂ）７０６ｇ、スチレンモノマー２６ｇ、原料（Ａ）１８５ｇ、ナフテン酸コバルト（コバルト含有量６％）１９ｇ、ｐ−トルエンスルホニルヒドラジド３８ｇ、粒径２００μｍ〜３００μｍのアルミナ質砥粒（日本軽金属製、ＷＡ Ｆ６０）２５３０ｇ、気孔材（日本フィライト製、フィライト（登録商標）ＦＧ）７９ｇ、氷晶石２５０ｇ、過酸化物硬化剤（化薬アクゾ製、３２８Ｅ）４９ｇを短時間に均一分散混合できるプロペラ回転機で約６０秒攪拌して均一にし、外径２５５ｍｍφ×厚み３０ｍｍ×穴径３５ｍｍφの砥石注型用金型に充填した。これを室温２０±５℃で放置したところ約２５分程度で発熱が認められ、次第に硬化した。硬化終了後、さらに１３０℃にて１時間アフターキュアして実施例４の研削砥石を得た。
【０１１６】
（実施例５）
ビニルエステル樹脂（昭和高分子製、Ｈ６００）３５３ｇ、不飽和ポリエステル樹脂（三井化学製、Ｒ−１３０Ｂ）３５３ｇ、スチレンモノマー２６ｇ、原料（Ａ）１８５ｇ、ナフテン酸コバルト（コバルト含有量６％）１９ｇ、ｐ−トルエンスルホニルヒドラジド３８ｇ、粒径２００μｍ〜３００μｍのアルミナ質砥粒（日本軽金属製、ＷＡ Ｆ６０）２５３０ｇ、気孔材（日本フィライト製、フィライト（登録商標）ＦＧ）７９ｇ、氷晶石２５０ｇ、過酸化物硬化剤（化薬アクゾ製、３２８Ｅ）４９ｇを短時間に均一分散混合できるプロペラ回転機で約６０秒攪拌して均一にし、外径２５５ｍｍφ×厚み３０ｍｍ×穴径３５ｍｍφの砥石注型用金型に充填した。これを室温２０±５℃で放置したところ約２０分程度で発熱が認められ、次第に硬化した。硬化終了後、さらに１３０℃にて１時間アフターキュアして実施例５の研削砥石を得た。
【０１１７】
（実施例６）
ビニルエステル樹脂（昭和高分子製、Ｈ６００）２６１ｇ、不飽和ポリエステル樹脂（三井化学製、Ｒ−１３０Ｂ）２６１ｇ、スチレンモノマー２６ｇ、上記原料（Ａ）３６９ｇ、ナフテン酸コバルト（コバルト含有量６％）１９ｇ、ｐ−トルエンスルホニルヒドラジド３８ｇ、粒径２００μｍ〜３００μｍのアルミナ質砥粒（日本軽金属製、ＷＡ Ｆ６０）２５３０ｇ、気孔材（日本フィライト製、フィライト（登録商標）ＦＧ）７９ｇ、氷晶石２５０ｇ、過酸化物硬化剤（化薬アクゾ製、３２８Ｅ）４９ｇを短時間に均一分散混合できるプロペラ回転機で約６０秒攪拌して均一にし、外径２５５ｍｍφ×厚み３０ｍｍ×穴径３５ｍｍφの砥石注型用金型に充填した。これを室温２０±５℃で放置したところ約２０分程度で発熱が認められ、次第に硬化した。硬化終了後、さらに１３０℃にて１時間アフターキュアして実施例６の研削砥石を得た。
【０１１８】
（実施例７）
ビニルエステル樹脂（昭和高分子製、Ｈ６００）１２２ｇ、不飽和ポリエステル樹脂（三井化学製、Ｒ−１３０Ｂ）１２２ｇ、スチレンモノマー２６ｇ、上記原料（Ａ）６４７ｇ、ナフテン酸コバルト（コバルト含有量６％）１９ｇ、ｐ−トルエンスルホニルヒドラジド３８ｇ、粒径２００μｍ〜３００μｍのアルミナ質砥粒（日本軽金属製、ＷＡ Ｆ６０）２５３０ｇ、気孔材（日本フィライト製、フィライト（登録商標）ＦＧ）７９ｇ、氷晶石２５０ｇ、過酸化物硬化剤（化薬アクゾ製、３２８Ｅ）４９ｇを短時間に均一分散混合できるプロペラ回転機で約６０秒攪拌して均一にし、外径２５５ｍｍφ×厚み３０ｍｍ×穴径３５ｍｍφの砥石注型用金型に充填した。これを室温２０±５℃で放置したところ約２５分程度で発熱が認められ、次第に硬化した。硬化終了後、さらに１３０℃にて１時間アフターキュアして実施例７の研削砥石を得た。
【０１１９】
（実施例８）
原料（Ａ）の代わりに原料（Ｂ）を使用した以外は実施例５と同様に実施し、実施例８の研削砥石を得た。
【０１２０】
（比較例１）
ビニルエステル樹脂（昭和高分子製、Ｈ６００）４４６ｇ、不飽和ポリエステル樹脂（三井化学製、Ｒ−１３０Ｂ）４４６ｇ、スチレンモノマー２６ｇ、収縮防止剤（日本油脂製、ＳＶ１０Ｂ−３０）８ｇ、ナフテン酸コバルト（コバルト含有量６％）１９ｇ、ｐ−トルエンスルホニルヒドラジド３８ｇ、粒径２００μｍ〜３００μｍのアルミナ質砥粒（日本軽金属製、ＷＡ Ｆ６０）２５３０ｇ、気孔材（日本フィライト製、フィライト（登録商標）ＦＧ）７９ｇ、氷晶石２５０ｇ、過酸化物硬化剤（化薬アクゾ製、３２８Ｅ）４９ｇを短時間に均一分散混合できるプロペラ回転機で約６０秒攪拌して均一にし、外径２５５ｍｍφ×厚み３０ｍｍ×穴径３５ｍｍφの砥石注型用金型に充填した。これを室温２０±５℃で放置したところ約２０分程度で発熱が認められ、次第に硬化した。硬化終了後、さらに１３０℃にて１時間アフターキュアして比較例１の研削砥石を得た。
【０１２１】
（研削テスト）
直径２５ｍｍのステンレスの丸棒を、その断面円の中心軸を基軸として３２２／分で回転させておき、実施例および比較例で作成した砥石を周速度１，８００ｍ／分で回転させながら、０．０８ＭＰａの圧力で回転中のステンレス丸棒に接触させた。ステンレス丸棒と砥石との接点部分には研削液（アルカリ性水溶液）を供給し、１５分間の研削を実施した。
【０１２２】
研削量
１５分間の研削後にステンレス丸棒を乾燥させ、その質量減少を測定し研削量とした。実施例１〜実施例８の砥石は比較例１の砥石より研削量が多く、良く削れる砥石であった。結果を表１に記す。
【０１２３】
電流値
砥石を一定の周速度（１８００ｍ／分）で回転させて研削した時に要した電流値を、１回１５分の研削工程で研削開始から５分及び１０分の時点で読み取った。なお、ここでいう電流値とは、砥石を回転させるための電動式モーターに供給する電流の値である。実際には、モーターに電気を供給するための電気回路において、モーターと直列に電流計を設置して電流値を読み取った。このようにして読み取った電流値は、砥石を一定の周速度で回転させるために必要なモーターの駆動力の指標となり、研削抵抗の大きな砥石ほど大きな駆動力を必要とし、電流値が大きくなる。実施例１〜実施例８の砥石はすべて比較例１の砥石より電流値が低かった。このことから実施例１〜実施例８の砥石は研削抵抗が低い砥石である。結果を表１に記す。
【０１２４】
【表１】

【０１２５】
【発明の効果】
本発明によれば、特定の構造を有する化合物（Ａ）と不飽和ポリエステル樹脂及び／又はビニルエステル樹脂とを含有する砥石用樹脂組成物を原料の一部とする砥石は、研削抵抗が低くよって発熱が小さいために研削精度の高い研削・研磨が可能な砥石を提供することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a resin composition for a grindstone, a method for producing a grindstone using the resin composition for a grindstone, and a grindstone using the composition for a grindstone.
[0002]
More specifically, a grindstone resin composition capable of producing a grindstone having low grinding resistance and accurate grinding compared to conventional grindstones, a method for producing a grindstone using the grindstone resin composition, and The present invention relates to a whetstone using the whetstone composition.
[0003]
[Prior art]
As a resin composition for a grindstone in which abrasive grains are bonded with a resin (hereinafter referred to as “resinoid grindstone”), phenolic resins, phenol-polyvinyl alcohol resins, polyurethane resins, epoxy resins, and the like are known. Yes. In general, a grindstone generates heat locally due to contact resistance between a workpiece and the grindstone when grinding, and sometimes exceeds 100 ° C. when it is high. When the grinding stone temperature becomes high during grinding in the resinoid grinding wheel, the binder of the resinoid grinding stone is thermally deformed or the binder is deteriorated by an alkaline grinding fluid (pH 9 to pH11), so that accurate grinding cannot be performed. For this reason, studies have been made to increase the heat resistance of resins used as binders for resinoid grinding wheels.
[0004]
For example, Japanese Patent Application Laid-Open No. 62-009876 discloses a grinding wheel with improved heat resistance using a thermosetting resin containing a terephthalic acid diallyl ester copolymer as an essential component as a binder. However, the demand for a grindstone that can be ground with higher accuracy is insufficient.
[0005]
In order to suppress heat generation during grinding, a grindstone in which moisture is dispersed in the grindstone to provide a cooling effect is also known. For example, Japanese Patent Application Laid-Open No. 54-163492 discloses a ground body in which a resin having an unsaturated bond is crosslinked and a binder is used, and water is dispersed in the binder. The water dispersed in the binder exhibits a cooling effect during grinding, and an effect of suppressing a temperature rise during grinding is recognized. However, due to the lack of sufficient rigidity, the problem that precision grinding becomes difficult, and the fact that water is evenly distributed in the grindstone when mass-produced on the production line strictly controls the manufacturing process. There was a problem that it was necessary and had a great influence on the manufacturing cost.
[0006]
Japanese Laid-Open Patent Publication No. 61-21139 discloses a grindstone using a polyamideimide resin. Furthermore, JP-A-11-300622 discloses a grindstone having improved wettability and moldability with abrasive grains using a polyimide resin. A grindstone using these resins has a problem that although the heat resistance is relatively high, the resin used is expensive.
[0007]
As described above, the resinoid grindstone has a problem that its grinding performance deteriorates due to heat generated during grinding. In order to solve this problem, it is important not only to increase the heat resistance of the resin as a binder but also to suppress the heat generated during grinding. In particular, when precision grinding is performed on materials such as stainless steel with low thermal conductivity, there is a problem that grinding burn is likely to occur due to the heat generated during grinding. It was desired.
[0008]
As one method for suppressing heat generated during grinding, Japanese Patent Laid-Open No. 10-138149 discloses a method for manufacturing a grindstone in which pores are uniformly formed. According to this method, problems such as grinding burn can be eliminated, and a long-life grindstone can be provided. However, the recent demand for more accurate grinding has still been insufficient.
[0009]
In general, the heat generated during grinding is closely related to the grinding resistance at the contact interface between the grindstone and the workpiece. Therefore, as another method for suppressing the heat generated during grinding, a method of effectively dropping off abrasive grains having a poor sharpness can be considered. When the sharpness of the abrasive grains existing on the surface is reduced to some extent, the grinding resistance can be kept low by effectively removing the abrasive grains that have become poorly sharpened, and as a result, the heat generated during grinding can be suppressed. Can do.
[0010]
Generally, a resinoid grindstone has a self-regenerative function in which new abrasive grains appear on the surface when the abrasive grains on the surface of the grindstone gradually fall off together with the binder resin. This self-regenerating function is required to have an ability to hold the abrasive grains moderately in terms of polishing performance, and to have an ability to appropriately wear the binder resin itself in terms of suppressing heat generated during grinding. Therefore, a balance between these two conflicting performances is important.
[0011]
However, in the binder resin composition for conventional resinoid grinding wheels, there is no example in which this point of view has been studied, and resin compositions that can provide resinoid grinding wheels that are excellent in polishing properties and have a small calorific value are known. There wasn't.
[0012]
[Problems to be solved by the invention]
One object of the present invention is to provide a resin composition for a grindstone that can produce a grindstone that enables accurate grinding by suppressing the grinding resistance and reducing heat generation.
[0013]
Another object is to provide a method for producing a grindstone using the resin composition for a grindstone, and a grindstone using the composition for a grindstone.
[0014]
[Means for Solving the Problems]
The inventors of the present invention have made extensive studies to solve the above problems. As a result, in a grinding wheel using a thermosetting resin as a binder, a grinding wheel using a resin composition containing a compound having a specific structure and an unsaturated polyester resin and / or vinyl ester resin as a binder is ground. The inventors have found that the resistance is low, the heat generation is low, and the grinding can be performed with high accuracy, and the present invention has been completed.
[0015]
That is, the present invention (I) is a grindstone resin composition comprising the following (A) and (B).
[0016]
(A) Compound having at least one group represented by general formula (1) as a terminal group and a group represented by general formula (2) as a repeating unit
(B) Unsaturated polyester resin and / or vinyl ester resin
General formula (1)
[0017]
[Chemical 9]

(In the general formula (1), X¹Is an organic residue derived from a polyvalent carboxylic acid having 2 to 3 carboxylic acid groups each independently. In general formula (1), n is 1 or 2, and X¹N has 1 when X has 2 carboxylic acid groups, and X¹When n has 3 carboxylic acid groups, n is 2. In general formula (1), Y¹Represents an alkyl group, an allyl group, or a methallyl group. However, Y which exists in 1 molecule of compound (A)¹At least one of these must be an allyl group or a methallyl group. )
[0018]
General formula (2)
[0019]
Embedded image

(In the general formula (2), X²Is an organic residue derived from a polyvalent carboxylic acid having 2 to 3 carboxylic acid groups each independently. In general formula (2), m is 1 or 2, and X²M has 1 when X has two carboxylic acid groups, and X²When m has 3 carboxylic acid groups, m is 2. In general formula (2), Y²Represents an organic residue derived from a polyhydric alcohol having 2 to 20 carbon atoms and having 2 to 6 hydroxyl groups. However, Y²May have a branched structure having an ester bond as a terminal group and the general formula (2) as a repeating unit. )
[0020]
Moreover, this invention (II) is a manufacturing method of the grindstone characterized by making it harden | cure using a radical polymerization initiator, after mixing an abrasive grain with the resin composition for grindstones of this invention (I).
[0021]
Furthermore, the present invention (III) is a grindstone manufactured by the method for producing a grindstone of the present invention (II).
[0022]
Furthermore, this invention consists of the following matters, for example.
[1] A grindstone resin composition comprising the following (A) and (B):
(A) a compound having at least one group represented by general formula (1) as a terminal group and a group represented by general formula (2) as a repeating unit (hereinafter also referred to as “compound (A)”) I will write.)
(B) Unsaturated polyester resin and / or vinyl ester resin (hereinafter also referred to as “compound (B)”)
[0023]
General formula (1)
Embedded image

(In the general formula (1), X¹Is an organic residue derived from a polyvalent carboxylic acid having 2 to 3 carboxylic acid groups each independently. In general formula (1), n is 1 or 2, and X¹N has 1 when X has 2 carboxylic acid groups, and X¹When n has 3 carboxylic acid groups, n is 2. In general formula (1), Y¹Represents an alkyl group, an allyl group, or a methallyl group. However, Y which exists in 1 molecule of compound (A)¹At least one of these must be an allyl group or a methallyl group. )
[0024]
General formula (2)
Embedded image

(In the general formula (2), X²Is an organic residue derived from a polyvalent carboxylic acid having 2 to 3 carboxylic acid groups each independently. In general formula (2), m is 1 or 2, and X²M has 1 when X has two carboxylic acid groups, and X²When m has 3 carboxylic acid groups, m is 2. In general formula (2), Y²Represents an organic residue derived from a polyhydric alcohol having 2 to 20 carbon atoms and having 2 to 6 hydroxyl groups. However, Y²May have a branched structure having an ester bond as a terminal group and the general formula (2) as a repeating unit. )
[0025]
[2] In addition to the following (A) and (B), further comprising (C) a reactive diluent having polymerizability, a resin composition for a grindstone.
(A) a compound having at least one group represented by general formula (1) as a terminal group and a group represented by general formula (2) as a repeating unit (hereinafter also referred to as “compound (A)”) I will write.)
(B) Unsaturated polyester resin and / or vinyl ester resin (hereinafter also referred to as “compound (B)”)
[0026]
General formula (1)
Embedded image

(In the general formula (1), X¹Is an organic residue derived from a polyvalent carboxylic acid having 2 to 3 carboxylic acid groups each independently. In general formula (1), n is 1 or 2, and X¹N has 1 when X has 2 carboxylic acid groups, and X¹When n has 3 carboxylic acid groups, n is 2. In general formula (1), Y¹Represents an alkyl group, an allyl group, or a methallyl group. However, Y which exists in 1 molecule of compound (A)¹At least one of these must be an allyl group or a methallyl group. )
[0027]
General formula (2)
Embedded image

(In the general formula (2), X²Is an organic residue derived from a polyvalent carboxylic acid having 2 to 3 carboxylic acid groups each independently. In general formula (2), m is 1 or 2, and X²M has 1 when X has two carboxylic acid groups, and X²When m has 3 carboxylic acid groups, m is 2. In general formula (2), Y²Represents an organic residue derived from a polyhydric alcohol having 2 to 20 carbon atoms and having 2 to 6 hydroxyl groups. However, Y²May have a branched structure having an ester bond as a terminal group and the general formula (2) as a repeating unit. )
[0028]
[3] In any one of [1] or [2], the following (A) is contained in the range of 1% by mass to 99% by mass, and (B) in the range of 1% by mass to 99% by mass. The resin composition for a grindstone as described.
(A) A compound having at least one group represented by the following general formula (1) as a terminal group and a group represented by the following general formula (2) as a repeating unit
(B) Unsaturated polyester resin and / or vinyl ester resin
[0029]
General formula (1)
Embedded image

(In the general formula (1), X¹Is an organic residue derived from a polyvalent carboxylic acid having 2 to 3 carboxylic acid groups each independently. In general formula (1), n is 1 or 2, and X¹N has 1 when X has 2 carboxylic acid groups, and X¹When n has 3 carboxylic acid groups, n is 2. In general formula (1), Y¹Represents an alkyl group, an allyl group, or a methallyl group. However, Y which exists in 1 molecule of compound (A)¹At least one of these must be an allyl group or a methallyl group. )
[0030]
General formula (2)
Embedded image

(In the general formula (2), X²Is an organic residue derived from a polyvalent carboxylic acid having 2 to 3 carboxylic acid groups each independently. In general formula (2), m is 1 or 2, and X²M has 1 when X has two carboxylic acid groups, and X²When m has 3 carboxylic acid groups, m is 2. In general formula (2), Y²Represents an organic residue derived from a polyhydric alcohol having 2 to 20 carbon atoms and having 2 to 6 hydroxyl groups. However, Y²May have a branched structure having an ester bond as a terminal group and the general formula (2) as a repeating unit. )
[0031]
[4] The following (A) is contained in the range of 1% by mass to 99% by mass, (B) in the range of 1% by mass to 99% by mass, and (C) in the range of 0% by mass to 50% by mass. The grindstone resin composition according to any one of [1] to [3].
(A) A compound having at least one group represented by the following general formula (1) as a terminal group and a group represented by the following general formula (2) as a repeating unit
(B) Unsaturated polyester resin and / or vinyl ester resin
(C) Reactive diluent having polymerizability
[0032]
General formula (1)
Embedded image

(In the general formula (1), X¹Is an organic residue derived from a polyvalent carboxylic acid having 2 to 3 carboxylic acid groups each independently. In general formula (1), n is 1 or 2, and X¹N has 1 when X has 2 carboxylic acid groups, and X¹When n has 3 carboxylic acid groups, n is 2. In general formula (1), Y¹Represents an alkyl group, an allyl group, or a methallyl group. However, Y which exists in 1 molecule of compound (A)¹At least one of these must be an allyl group or a methallyl group. )
[0033]
General formula (2)
Embedded image

(In the general formula (2), X²Is an organic residue derived from a polyvalent carboxylic acid having 2 to 3 carboxylic acid groups each independently. In general formula (2), m is 1 or 2, and X²M has 1 when X has two carboxylic acid groups, and X²When m has 3 carboxylic acid groups, m is 2. In general formula (2), Y²Represents an organic residue derived from a polyhydric alcohol having 2 to 20 carbon atoms and having 2 to 6 hydroxyl groups. However, Y²May have a branched structure having an ester bond as a terminal group and the general formula (2) as a repeating unit. )
[0034]
[5] X in general formula (1)¹Or X in the general formula (2)²At least one of these is an organic residue derived from at least one compound selected from itaconic acid or maleic acid. The resin composition for a grindstone according to any one of [1] to [4],
[0035]
[6] Any one of [2] to [5], wherein the reactive diluent having a polymerizable property (C) is one selected from the group consisting of vinyl compounds, allyl compounds, and mixtures thereof. The resin composition for grindstones described in 1.
[0036]
[7] A method for producing a grindstone, comprising mixing abrasive grains with the resin composition for a grindstone according to any one of [1] to [6] and then curing the mixture using a radical polymerization initiator.
[0037]
[8] The abrasive resin composition according to any one of [1] to [6] is mixed with abrasive grains, a pore material and / or a foaming agent, and then cured using a radical polymerization initiator. A manufacturing method of a grindstone.
[0038]
[9] The content of the abrasive grains is adjusted to be in the range of 10% by mass to 80% by mass with respect to the mass of the entire grindstone, and then cured using a radical polymerization initiator [7] or [8] The method for producing a grindstone according to any one of [8].
[0039]
[10] The abrasive grains are at least one selected from the group consisting of alumina abrasive grains, silicon carbide abrasive grains, cubic boron nitride abrasive grains, and diamond abrasive grains [7] to [9] ] The manufacturing method of the grindstone in any one of.
[0040]
[11] The method for producing a grindstone according to any one of [8] to [10], wherein the pore material has a diameter in a range of 50 μm to 300 μm.
[0041]
[12] The foaming agent is one selected from the group consisting of an azo compound, a nitroso compound, a sulfonyl hydrazide compound, and a mixture of two or more of these, [8] to [11] A manufacturing method of a grindstone.
[0042]
[13] The radical polymerization initiator is one kind selected from the group consisting of t-butyl peroxybenzoate, cumene hydroperoxide, and a mixture thereof [7] to [12] Method of manufacturing a grinding wheel.
[0043]
[14] The method for producing a grindstone according to any one of [7] to [13], wherein a redox accelerator is added to the radical polymerization initiator and then cured.
[0044]
[15] The method for producing a grindstone according to [14], wherein the redox accelerator is one selected from the group consisting of a cobalt carboxylate, a copper carboxylate, and a mixture thereof.
[0045]
[16] The method for producing a grindstone according to [14], wherein the redox accelerator is cobalt naphthenate.
[0046]
[17] The method for producing a grindstone according to any one of [7] to [16], which is cured at normal temperature.
[0047]
[18] A grindstone produced by the production method according to any one of [7] to [17].
[0048]
[19] A grindstone for grinding and / or polishing a stainless alloy, an aluminum metal and its alloy, or a nickel alloy produced by the production method according to any one of [7] to [17].
[0049]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in more detail.
First, the present invention (I) will be described. The present invention (I) is a grindstone resin composition comprising the following (A) and (B).
(A) Compound having at least one group represented by general formula (1) as a terminal group and a group represented by general formula (2) as a repeating unit
(B) Unsaturated polyester resin and / or vinyl ester resin
[0050]
General formula (1)
[0051]
Embedded image

(In the general formula (1), X¹Is an organic residue derived from a polyvalent carboxylic acid having 2 to 3 carboxylic acid groups each independently. In general formula (1), n is 1 or 2, and X¹N has 1 when X has 2 carboxylic acid groups, and X¹When n has 3 carboxylic acid groups, n is 2. In general formula (1), Y¹Represents an alkyl group, an allyl group, or a methallyl group. However, Y which exists in 1 molecule of compound (A)¹At least one of these must be an allyl group or a methallyl group. )
General formula (2)
[0052]
Embedded image

(In the general formula (2), X²Is an organic residue derived from a polyvalent carboxylic acid having 2 to 3 carboxylic acid groups each independently. In general formula (2), m is 1 or 2, and X²M has 1 when X has two carboxylic acid groups, and X²When m has 3 carboxylic acid groups, m is 2. In general formula (2), Y²Represents an organic residue derived from a polyhydric alcohol having 2 to 20 carbon atoms and having 2 to 6 hydroxyl groups. However, Y²May have a branched structure having an ester bond as a terminal group and the general formula (2) as a repeating unit. )
[0053]
The “whetstone” in the present invention refers to a product obtained by bonding various abrasive grains with a resin and hardening them. Further, the grindstone in the present invention has a function of cutting the work material by bringing it into contact with the work material while performing reciprocation, rotation, and / or movement combining the reciprocation and rotation. is there. Furthermore, the shape of the grindstone in the present invention is not particularly limited, and includes various shapes such as a disk, a cylinder, a dish shape, a bowl shape, and a square shape. The thing of a multilayer structure is also included.
[0054]
(A) a compound having at least one group represented by the general formula (1) as a terminal group and a group represented by the general formula (2) as a repeating unit used in the present invention (I) X in the general formula (1)¹And X in the general formula (2)²Is an organic residue derived from a polyvalent carboxylic acid having 2 to 3 carboxylic acid groups each independently.
[0055]
Specific examples of the polyvalent carboxylic acid having two carboxylic acid groups include terephthalic acid, isophthalic acid, phthalic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, adipic acid, malonic acid, succinic acid, and glutaric acid. , Sebacic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,4-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid, 2,7-naphthalene dicarboxylic acid, diphenyl-m, m ′ -Dicarboxylic acid, diphenyl-p, p'-dicarboxylic acid, benzophenone-4,4'-dicarboxylic acid, p-phenylenediacetic acid, p-carboxyphenylacetic acid, methylterephthalic acid, tetrachlorophthalic acid, endic acid anhydride, And chlorendic anhydride.
[0056]
Specific examples of the polyvalent carboxylic acid having three carboxylic acid groups include 1,2,4-trimellitic acid. Needless to say, the present invention is not limited to these specific examples.
[0057]
For example, X¹And X²Is an organic residue derived from terephthalic acid, General Formula (1) and General Formula (2) can be represented by Structural Formula-1 and Structural Formula-2, respectively.
Structural formula-1
[0058]
Embedded image

Structural formula-2
[0059]
Embedded image

[0060]
In order to increase the heat resistance of the grindstone, a polyvalent carboxylic acid having a benzene ring, a polyvalent carboxylic acid having an internal unsaturated bond, and / or a polyvalent carboxylic acid having three carboxylic acid groups are preferred. More preferred is terephthalic acid, isophthalic acid, itaconic acid or maleic acid.
[0061]
X in general formula (1)¹And X in the general formula (2)²Is an organic residue derived from a polyvalent carboxylic acid having 2 to 3 carboxylic acid groups each independently. For example, X¹All of these are organic residues derived from polyvalent carboxylic acids having the same structure, or organic residues derived from polyvalent carboxylic acids having all different structures. It is an organic residue derived from a polyvalent carboxylic acid having the following structure, and some of the others are so-called mixed structures such as an organic residue derived from a polyvalent carboxylic acid having another type of structure. However, there is no problem. Further, the mixed structure may be completely random or partly repeated.
[0062]
X²Similarly for X²All of these are organic residues derived from polyvalent carboxylic acids having the same structure, or organic residues derived from polyvalent carboxylic acids having all different structures. It is an organic residue derived from a polyvalent carboxylic acid having the following structure, and some others are mixed residues such as an organic residue derived from a polyvalent carboxylic acid having another type of structure. There is no problem. Further, the mixed structure may be completely random or partly repeated.
[0063]
In general formula (1), Y¹Represents an alkyl group, an allyl group, or a methallyl group. However, Y present in the compound (A)¹At least one of these must be an allyl group or a methallyl group. This is because at least one Y present in compound (A)¹Is an allyl group or a methallyl group, for example, all Y present in the compound (A)¹Means that the alkyl group does not correspond to the general formula (1).
[0064]
In general formula (2), Y²Each independently represents an organic residue derived from a polyhydric alcohol having 2 to 20 carbon atoms and having 2 to 6 hydroxyl groups.
[0065]
Specific examples of the polyhydric alcohol having two hydroxyl groups include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, neo Pentyl glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,1-cyclohexanedimethanol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 2-methylcyclohexane-1,1-dimethanol, 6-methyl-3-cyclohexane-1,1-dimethanol, 1,4-cyclohexanedimethanol , P-xylene glycol, m-xylene glycol, Glycol, tricyclodecane methanol, 2-methyl-cyclohexanedimethanol, bisphenol A · ethylene oxide adduct, bisphenol A · propylene oxide adduct and the like. Further, divalent alcohols containing an ether group in the main chain, such as diethylene glycol, dipropylene glycol, triethylene glycol, polyethylene glycol, and the like are also included.
[0066]
Specific examples of the polyhydric alcohol having 3 or more hydroxyl groups include glycerin, trimethylolpropane, trimethylolethane, pentaerythritol, dipentaerythritol, sorbitol and the like. Needless to say, the present invention is not limited to these specific examples.
[0067]
For example, Y²Is an organic residue derived from ethylene glycol, General Formula (2) can be represented by Structural Formula-3.
Structural formula-3
[0068]
Embedded image

(In Structural Formula-3, X²Is an organic residue derived from a polyvalent carboxylic acid having 2 to 3 carboxylic acid groups each independently. In Structural Formula-3, m is 1 or 2, and X²M has 1 when X has two carboxylic acid groups, and X²When m has 3 carboxylic acid groups, m is 2. )
[0069]
In general formula (2), Y²Each independently represents an organic residue derived from a polyhydric alcohol having 2 to 20 carbon atoms and having 2 to 6 hydroxyl groups. For example, Y²All of these are organic residues derived from polyhydric alcohols having the same structure, or organic residues derived from polyhydric alcohols having all different structures. It is possible to have a mixed structure in which the organic residue is derived from a polyhydric alcohol having an organic group, and some of the others are organic residues derived from a polyhydric alcohol having another type of structure. Further, the mixed structure may be completely random or partly repeated.
[0070]
Y²Can have a branched structure having the general formula (1) as a terminal group and the general formula (2) as a repeating unit by an ester bond. For example, Y²When an organic residue derived from trimethylolpropane, which is an example of a polyhydric alcohol having three hydroxyl groups, is present, the compound (A) contained in the composition of the present invention (I) has the structural formula-4. It can have the partial structure represented by these.
Structural formula-4
[0071]
Embedded image

(In Structural Formula-4, X^Three, X^Four, X^FiveIs an organic residue derived from a polyvalent carboxylic acid having 2 to 3 carboxylic acid groups each independently. In Structural Formula-4, s, t, and u are 1 or 2, and X^Three, X^Four, X^Five, T and u are 1 when X has two carboxylic acid groups, and X^Three, X^Four, X^FiveS, t, and u are 2 when has three carboxylic acid groups. )
[0072]
The unsaturated polyester resin used in the present invention (I) is based on an esterification reaction between a polyhydric alcohol and a polybasic acid having an unsaturated bond and / or an anhydride thereof (and a saturated polybasic acid if necessary). A product obtained by dissolving a condensation product in a polymerizable unsaturated compound such as styrene as necessary. However, what corresponds to the specific structure defined as a compound (A) shall not be included in unsaturated polyester resin in this specification.
[0073]
Specific examples of the unsaturated polyester resin include, for example, resins described in “Polyester Resin Handbook” (published by Nikkan Kogyo Shimbun 1988), “painting glossary” (edited by Color Material Association, 1993), and the like. It can be manufactured by a known method.
[0074]
Specific examples of the polybasic acid having an unsaturated bond or an anhydride thereof include fumaric acid, maleic anhydride, maleic acid, itaconic acid and the like. If necessary, saturated polybasic acid having no unsaturated bond such as phthalic anhydride, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, adipic acid or its anhydride, benzoic acid, abietic acid, Monocarboxylic acids such as cyclopentenylmaleic acid half esters can be used.
[0075]
Specific examples of the polyhydric alcohol include ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,5-pentanediol, and 1,6-hexanediol. 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, cyclohexane-1,4-dimethanol, ethylene oxide adduct of bisphenol A, propylene oxide adduct of bisphenol A, etc. Of polyhydric alcohols.
[0076]
The vinyl ester resin used in the present invention (I) is also called an epoxy (meth) acrylate, and is generally a compound having an epoxy group represented by an epoxy resin and a carboxyl compound having a polymerizable unsaturated group such as (meth) acrylic acid. A resin having a polymerizable unsaturated group produced by a ring-opening reaction with a carboxyl group, or a compound having a carboxyl group and an epoxy group of a polymerizable unsaturated compound having an epoxy group in the molecule such as glycidyl (meth) acrylate It is resin which has a polymerizable unsaturated group produced | generated by ring-opening reaction. Specifically, for example, it refers to a resin described in “Polyester Resin Handbook” (published by Nikkan Kogyo Shimbun, 1988), “Paint Glossary of Terms” (published by Color Material Association, 1993), etc. Can be manufactured.
[0077]
The epoxy resin used as the raw material for the vinyl ester resin includes bisphenol A diglycidyl ether and its high molecular weight homologue, glycidyl ether of bisphenol A alkylene oxide adduct, bisphenol F diglycidyl ether and its high molecular weight homologue, and bisphenol F alkylene oxide. Examples include adduct glycidyl ethers and novolac-type polyglycidyl ethers.
[0078]
The component (B) of the present invention (I) may be an unsaturated polyester resin, a vinyl ester resin, or a mixture of an unsaturated polyester resin and a vinyl ester resin. As the unsaturated polyester resin, one kind of unsaturated polyester resin can be used, or several kinds of unsaturated polyester resins can be mixed and used. As the vinyl ester resin, one kind of vinyl ester resin can be used, or several kinds of vinyl ester resins can be mixed and used. Needless to say, one kind and / or several kinds of unsaturated polyester resins and one kind and / or several kinds of vinyl ester resins can be mixed and used.
[0079]
In addition to the compound (A) and the compound (B), the resin composition for a grindstone of the present invention (I) is further controlled according to the purpose of adjusting the viscosity of the resin composition and controlling the physical properties of the final grindstone ( C) A reactive diluent having a polymerizable property (hereinafter also referred to as “compound (C)”) can be added.
[0080]
Specific examples of the compound (C) include vinyl compounds such as styrene, vinyl toluene, divinyl benzene, α-methyl styrene, methyl methacrylate, vinyl acetate, diallyl terephthalate, diallyl isophthalate, diallyl phthalate, triallyl isocyanurate. And allyl compounds. Needless to say, the reactive diluent is not limited to these specific examples.
[0081]
Of these, styrene, diallyl terephthalate, and / or diallyl isophthalate are preferably used, and styrene is particularly preferably used.
[0082]
There is no restriction | limiting in particular in the usage-amount of the compound (A), the compound (B), and the compound (C) in the resin composition for grindstones of this invention (I). Preferably, the compound (A) ranges from 1% to 99% by mass, the compound (B) ranges from 1% to 99% by mass, and the compound (C) ranges from 0% to 50% by mass.
[0083]
When the content of the compound (A) is too small, the grinding resistance of the grindstone is increased, and when the content of the compound (A) is too large, the raw material cost is increased. Therefore, the content of the compound (A) is preferably 1% by mass to 90% by mass, more preferably 5% by mass to 70% by mass, and further preferably 10% by mass to 50% by mass.
[0084]
For the same reason, the content of the compound (B) is preferably 1% by mass to 95% by mass, more preferably 10% by mass to 80% by mass, and further preferably 20% by mass to 70% by mass.
[0085]
Moreover, although a compound (C) can be used as needed, when there is too much content, there exists a possibility that the mechanical strength of a grindstone may fall. Therefore, the content of the compound (C) is preferably 0% by mass to 50% by mass, more preferably 5% by mass to 45% by mass, and still more preferably 10% by mass to 40% by mass.
[0086]
In addition, it cannot be overemphasized that the sum total of the mass% of a compound (A), a compound (B), and a compound (C) is 100 mass%. It is also the same that other additives such as abrasive grains, foaming agents, and pore materials, which will be described later, are not included here.
[0087]
Next, the present invention (II) will be described. The present invention (II) is a method for producing a grindstone characterized by mixing abrasive grains with the grindstone resin composition of the present invention (I) and then curing the mixture using a radical polymerization initiator.
[0088]
The abrasive grains used for the grindstone are not particularly limited, and conventionally known grains can be used. Specific examples include abrasive grains such as alumina abrasive grains, silicon carbide abrasive grains, boron carbide abrasive grains, cubic boron nitride abrasive grains, diamond abrasive grains, and the like. These abrasive grains may be used alone, but a plurality of kinds of abrasive grains may be mixed and used. Preferably used are alumina abrasive grains, silicon carbide abrasive grains, and cubic boron nitride abrasive grains, and more preferably alumina abrasive grains. Further, the grain size of the abrasive grains to be used is not particularly limited. When small abrasive grains are used, high-precision grinding is possible.
[0089]
The content of the abrasive grains in the grindstone molded body is not particularly limited, but if the abrasive content is large, the strength of the grindstone molded body is lowered, and if the abrasive content is low, the ability to grind as a grindstone is obtained. Lower. The content of abrasive grains is preferably 10% by mass to 80% by mass, more preferably 15% by mass to 60% by mass, and still more preferably 20% by mass to 50% by mass.
[0090]
A conventionally well-known thing can be used as a radical polymerization initiator. Specifically, for example, benzoyl peroxide, dicumyl peroxide, t-butyl hydroperoxide, di-t-butyl peroxy-3,3,5-trimethylcyclohexane, methyl ethyl ketone peroxide, cyclohexanone peroxide, methyl acetoacetate Examples include peroxide, acetylacetone peroxide, cumene hydroperoxide, benzoyl peroxide, t-butylperoxy-2-ethylhexanoate, t-butylperoxybenzoate, etc. It can also be used. Needless to say, the radical polymerization initiator is not limited to the above specific examples, and may be any compound that decomposes and generates radicals. The curing temperature is selected depending on the properties of the radical polymerization initiator used, and can be appropriately selected depending on the thermal decomposition half-life.
[0091]
In the manufacturing method of the grindstone of this invention (II), it can also take the manufacturing method which hardens using a radical polymerization initiator, after mixing a pore material and / or a foaming agent in addition to an abrasive grain.
[0092]
In order to suppress cooling of the grinding surface, removal of shavings, and clogging of the grindstone, it is preferable that pores exist in the grindstone. A pore material and / or a foaming agent can be added to generate the pores.
[0093]
Examples of the pore material include inorganic balloons and / or organic balloons. The inorganic balloon refers to a gas in which a gas is enclosed in a shell made of an inorganic material such as silica and / or alumina, and the thickness of the shell and the gas in the shell are not particularly limited. The organic balloon refers to a gas in which a gas is enclosed in a shell made of an organic material such as polystyrene, polyethylene, or polypropylene, and the thickness of the shell and the gas in the shell are not particularly limited. Specifically, glass balloon, shirasu balloon, silica balloon, carbon balloon, phenol resin balloon, vinylidene chloride resin balloon, polystyrene resin balloon, polyethylene resin balloon, polypropylene resin balloon, zirconia balloon, alumina balloon, fly ash balloon, perlite balloon Etc. can be illustrated.
[0094]
Since the size of the pore material affects the grinding performance, it is preferable to select a pore material having an appropriate size. The diameter of the balloon is preferably 5 μm to 1000 μm, more preferably 10 μm to 500 μm, and still more preferably 50 μm to 300 μm.
[0095]
The foaming agent is not particularly limited as long as it decomposes by the heat generated when the resin composition for a grindstone of the present invention (I) is cured and generates a gas. Examples include azo compounds, nitroso compounds, sulfonyl hydrazide compounds, and the like.
[0096]
Specifically, for example, azodicarbonamide, azobisisobutyronitrile, N, N′-dinitrosopentamethylenetetramine, p-toluenesulfonylhydrazine, 4,4′-oxybis (benzenesulfonylhydrazide) and the like are exemplified. Can do. These may be used alone or in combination. Those preferably used are N, N'-dinitrosopentamethylenetetramine and p-toluenesulfonylhydrazine.
[0097]
As other additives, cryolite, inorganic chloride, inorganic sulfide and the like can be added for the purpose of adjusting the viscosity of the composition before curing. These additives have the effect of more uniformly dispersing the abrasive grains in the resin.
[0098]
In the manufacturing method of the grindstone of this invention (II), it can also take the manufacturing method hardened after adding a redox promoter to a radical polymerization initiator.
[0099]
Examples of the redox accelerator include cobalt naphthenate, cobalt octylate, cobalt stearate, copper naphthenate and the like, and preferably used is copper naphthenate.
[0100]
Peroxides used with redox accelerators include methyl ethyl ketone peroxide, cyclohexanone peroxide, methyl acetoacetate peroxide, acetylacetone peroxide, cumene hydroperoxide, benzoyl peroxide, t-butylperoxy-2-ethylhexanoate , T-butyl peroxybenzoate and the like, and the above peroxides can be used in combination. Preferably used is cumene hydroperoxide and / or t-butyl peroxybenzoate.
[0101]
Further, in order to accelerate the curing, an auxiliary accelerator can be added to the peroxide and the redox accelerator. Examples of the co-promoter include N, N′-dimethylacetoacetamide, acetylacetone, dimedone, dibenzoylmethane, acetylcyclopentane, methyl acetoacetate, ethyl acetoacetate, acetylbutyrolactone, and dimethylaniline.
[0102]
In the method for producing a grindstone of the present invention (II), the grindstone resin composition can be cured at room temperature to produce a grindstone. Here, “curing at room temperature” means that the material is cured without being artificially heated extremely. The term “artificially heated extremely” as used herein means that heat energy or the like is supplied at the will of the operator, and the material before curing is set to 100 ° C. or higher. Therefore, even if the temperature is 100 ° C. or higher due to heat generated when the resin raw material is cured (so-called curing heat generation), it does not correspond to “artificial heating extremely”.
[0103]
Further, for example, it may be cured by leaving it in a place where the temperature is adjusted to 25 ° C., or it may be left in a place where the temperature fluctuates in the range of −20 ° C. to 60 ° C. due to the influence of the natural environment on the earth. You may let them. Furthermore, for the purpose of accelerating the curing, it may be left and cured in a place where the temperature is adjusted to 50 ° C., for example, or may be left and cured in a place where the temperature is adjusted to 10 ° C. However, if the temperature is too high, curing is too fast, and there is a risk that the curing reaction may run away, which is not preferable. On the other hand, if the temperature is too low, curing takes time, which is not economical.
[0104]
Further, the term “cured” as used herein means a state in which the polymerization reaction has proceeded to such an extent that the resin composition can be released from a desired mold. Therefore, the reaction rate of the functional group having polymerizability is not particularly problematic.
[0105]
In normal temperature curing, curing is usually performed by leaving the mold in a mold having a desired shape. However, in order to stabilize the shape of the grindstone molding, it can be cured by applying pressure. The mold is not particularly limited as long as it is a mold having a desired shape as a grindstone, but a material that does not greatly deform the mold due to heat generated when the resin is cured is preferable. In general, a metal material such as stainless steel or a resin material such as Fiberglass Reinforced Plastic having mechanical strength and heat resistance can be used.
[0106]
The grindstone after curing may be subjected to heat treatment (after cure) as necessary in order to increase the degree of polymerization of the resin. After-curing may be performed by removing the grindstone from the mold, or may be performed while being put in the mold. The after-curing temperature is usually in the range of 100 ° C. to 200 ° C., preferably in the range of 110 ° C. to 180 ° C., more preferably in the range of 120 ° C. to 160 ° C., although it depends on the composition of the resin used.
[0107]
Finally, the present invention (III) will be described. The present invention (III) is a grindstone manufactured by the method for producing a grindstone of the present invention (II).
[0108]
The grindstone according to the present invention (III) has a performance capable of grinding or polishing a wide variety of materials. Among these, stainless steel alloys, aluminum metals and alloys thereof, or nickel alloys can be preferably used for grinding and polishing. In particular, since the heat generated during grinding is lower than that of a conventional grindstone, more precise grinding and polishing are possible.
[0109]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention in more detail, this invention is not limited to these Examples, unless it deviates from the main point of this invention.
[0110]
(Synthesis Example 1)
A 2-liter three-necked flask equipped with a distillation apparatus was charged with 740 g of diallyl terephthalate, 432 g of dimethyl malate, 419 g of propylene glycol, and 1.3 g of dibutyl tin oxide and heated to 170 ° C. in a nitrogen stream to produce The coming alcohol was distilled off. When the distilled alcohol reached about 340 g, the pressure inside the reaction system was gradually reduced to 6650 Pa to increase the alcohol distillation rate. When the distillate almost disappeared, the reaction system was 530 Pa and further reacted for 1 hour to cool the reaction product. Styrene was added to the obtained reaction product so that the styrene content was 30% by mass. This is hereinafter referred to as raw material (A).
[0111]
(Synthesis Example 2)
A 2-liter three-necked flask equipped with a distillation apparatus was charged with 740 g of diallyl terephthalate, 475 g of dimethyl itaconate, 419 g of propylene glycol, and 1.3 g of dibutyltin oxide, and heated to 170 ° C. under a nitrogen stream. The coming alcohol was distilled off. When the distilled alcohol reached about 340 g, the pressure in the reaction system was gradually reduced to 6650 Pa to increase the alcohol distillation rate. When the distillate almost disappeared, the reaction system was 530 Pa and further reacted for 1 hour to cool the reaction product. Styrene was added to the obtained reaction product so that the styrene content was 30% by mass. This is hereinafter referred to as raw material (B).
[0112]
Example 1
706 g of vinyl ester resin (manufactured by Showa Polymer, H600), 26 g of styrene monomer, 185 g of raw material (A), 19 g of cobalt naphthenate (cobalt content 6%), 38 g of p-toluenesulfonyl hydrazide, alumina having a particle size of 200 μm to 300 μm 2530 g of abrasive grains (made by Nippon Light Metal, WA F60), 79 g of pore material (made by Nihon Philite, Philite (registered trademark) FG), 250 g of cryolite, 49 g of peroxide curing agent (made by Kayaku Akzo, 328E) for a short time The mixture was stirred for about 60 seconds with a propeller rotating machine capable of uniformly dispersing and mixing, and filled in a grinding stone casting mold having an outer diameter of 255 mmφ × thickness 30 mm × hole diameter 35 mmφ. When this was left at room temperature of 20 ± 5 ° C., heat generation was observed in about 15 minutes, and it gradually hardened. After the curing was completed, the product was after-cured at 130 ° C. for 1 hour to obtain the grinding wheel of Example 1.
[0113]
(Example 2)
424 g of vinyl ester resin (made by Showa High Polymer, H600), 282 g of unsaturated polyester resin (made by Mitsui Chemicals, R-130B), 26 g of styrene monomer, 185 g of raw material (A), 19 g of cobalt naphthenate (cobalt content 6%), 38 g of p-toluenesulfonyl hydrazide, 2530 g of alumina abrasive grains (Nippon Light Metal, WA F60) with a particle diameter of 200 μm to 300 μm, 79 g of pore material (manufactured by Nippon Philite, Philite (registered trademark) FG), 250 g of cryolite, peroxide A mold for grinding stone casting with an outer diameter of 255 mmφ × thickness of 30 mm × hole diameter of 35 mmφ by stirring for about 60 seconds with a propeller rotating machine capable of uniformly dispersing and mixing 49 g of a product curing agent (made by Kayaku Akzo, 328E). Filled. When this was left at room temperature of 20 ± 5 ° C., heat generation was observed in about 20 minutes, and it gradually hardened. After the curing was completed, the product was after-cured at 130 ° C. for 1 hour to obtain the grinding wheel of Example 2.
[0114]
(Example 3)
282 g of vinyl ester resin (manufactured by Showa Polymer, H600), 424 g of unsaturated polyester resin (manufactured by Mitsui Chemicals, R-130B), 26 g of styrene monomer, 185 g of raw material (A), 19 g of cobalt naphthenate (cobalt content 6%), 38 g of p-toluenesulfonyl hydrazide, 2530 g of alumina abrasive grains (Nippon Light Metal, WA F60) with a particle diameter of 200 μm to 300 μm, 79 g of pore material (manufactured by Nippon Philite, Philite (registered trademark) FG), 250 g of cryolite, peroxide A mold for grinding stone casting with an outer diameter of 255 mmφ × thickness of 30 mm × hole diameter of 35 mmφ by stirring for about 60 seconds with a propeller rotating machine capable of uniformly dispersing and mixing 49 g of a product curing agent (made by Kayaku Akzo, 328E). Filled. When this was left at room temperature of 20 ± 5 ° C., heat generation was observed in about 20 minutes, and it gradually hardened. After the curing was completed, the mixture was after-cured at 130 ° C. for 1 hour to obtain the grinding wheel of Example 3.
[0115]
Example 4
706 g of unsaturated polyester resin (Mitsui Chemicals, R-130B), 26 g of styrene monomer, 185 g of raw material (A), 19 g of cobalt naphthenate (cobalt content 6%), 38 g of p-toluenesulfonyl hydrazide, particle size 200 μm to 300 μm 2530 g of alumina abrasive grains (Nippon Light Metal, WA F60), 79 g of pore material (Nippon Philite, Philite (registered trademark) FG), 250 g of cryolite, 49 g of peroxide hardener (manufactured by Kayaku Akzo, 328E) The mixture was stirred and homogenized for about 60 seconds with a propeller rotating machine capable of uniformly dispersing and mixing in a short time, and filled in a grinding stone casting mold having an outer diameter of 255 mmφ × thickness of 30 mm × hole diameter of 35 mmφ. When this was left at room temperature of 20 ± 5 ° C., heat generation was observed in about 25 minutes, and it gradually hardened. After the completion of curing, after-curing was further performed at 130 ° C. for 1 hour to obtain a grinding wheel of Example 4.
[0116]
(Example 5)
353 g of vinyl ester resin (manufactured by Showa Polymer, H600), 353 g of unsaturated polyester resin (manufactured by Mitsui Chemicals, R-130B), 26 g of styrene monomer, 185 g of raw material (A), 19 g of cobalt naphthenate (cobalt content 6%), 38 g of p-toluenesulfonyl hydrazide, 2530 g of alumina abrasive grains (Nippon Light Metal, WA F60) with a particle diameter of 200 μm to 300 μm, 79 g of pore material (manufactured by Nippon Philite, Philite (registered trademark) FG), 250 g of cryolite, peroxide A mold for grinding stone casting with an outer diameter of 255 mmφ × thickness of 30 mm × hole diameter of 35 mmφ by stirring for about 60 seconds with a propeller rotating machine capable of uniformly dispersing and mixing 49 g of a product curing agent (made by Kayaku Akzo, 328E). Filled. When this was left at room temperature of 20 ± 5 ° C., heat generation was observed in about 20 minutes, and it gradually hardened. After the completion of curing, after-curing was further performed at 130 ° C. for 1 hour to obtain a grinding wheel of Example 5.
[0117]
(Example 6)
261 g vinyl ester resin (Showa High Polymer, H600), 261 g unsaturated polyester resin (R-130B, Mitsui Chemicals), 26 g styrene monomer, 369 g raw material (A), 19 g cobalt naphthenate (cobalt content 6%) , 38 g of p-toluenesulfonyl hydrazide, 2530 g of alumina abrasive grains (Nippon Light Metal, WA F60) with a particle size of 200 μm to 300 μm, 79 g of pore material (manufactured by Nihon Philite, Philite (registered trademark) FG), 250 g of cryolite, A grinding wheel casting mold with an outer diameter of 255 mmφ × thickness of 30 mm × hole diameter of 35 mmφ by stirring for 60 seconds with a propeller rotator capable of uniformly dispersing and mixing 49 g of oxide curing agent (manufactured by Kayaku Akzo, 328E). Filled the mold. When this was left at room temperature of 20 ± 5 ° C., heat generation was observed in about 20 minutes, and it gradually hardened. After the curing was completed, the mixture was after-cured at 130 ° C. for 1 hour to obtain the grinding wheel of Example 6.
[0118]
(Example 7)
122 g vinyl ester resin (Showa High Polymer, H600), 122 g unsaturated polyester resin (R-130B, Mitsui Chemicals), 26 g styrene monomer, 647 g raw material (A), 19 g cobalt naphthenate (cobalt content 6%) , 38 g of p-toluenesulfonyl hydrazide, 2530 g of alumina abrasive grains (Nippon Light Metal, WA F60) with a particle size of 200 μm to 300 μm, 79 g of pore material (manufactured by Nihon Philite, Philite (registered trademark) FG), 250 g of cryolite, A grinding wheel casting mold with an outer diameter of 255 mmφ × thickness of 30 mm × hole diameter of 35 mmφ by stirring for 60 seconds with a propeller rotator capable of uniformly dispersing and mixing 49 g of oxide curing agent (manufactured by Kayaku Akzo, 328E). Filled the mold. When this was left at room temperature of 20 ± 5 ° C., heat generation was observed in about 25 minutes, and it gradually hardened. After the completion of curing, after-curing was further performed at 130 ° C. for 1 hour to obtain a grinding wheel of Example 7.
[0119]
(Example 8)
The grinding stone of Example 8 was obtained in the same manner as in Example 5 except that the raw material (B) was used instead of the raw material (A).
[0120]
(Comparative Example 1)
446 g of vinyl ester resin (manufactured by Showa Polymer, H600), 446 g of unsaturated polyester resin (manufactured by Mitsui Chemicals, R-130B), 26 g of styrene monomer, 8 g of an anti-shrink agent (manufactured by NOF Corporation, SV10B-30), cobalt naphthenate ( 19 g of cobalt content), 38 g of p-toluenesulfonyl hydrazide, 2530 g of alumina abrasive grains (Nippon Light Metal, WA F60) having a particle size of 200 μm to 300 μm, 79 g of pore material (manufactured by Nippon Philite, Philite (registered trademark) FG) , 250 g of cryolite and 49 g of peroxide curing agent (manufactured by Kayaku Akzo, 328E) are stirred and homogenized for about 60 seconds with a propeller rotating machine capable of uniformly dispersing and mixing in a short time, outer diameter 255 mmφ × thickness 30 mm × hole diameter A 35 mmφ grinding wheel casting mold was filled. When this was left at room temperature of 20 ± 5 ° C., heat generation was observed in about 20 minutes, and it gradually hardened. After the curing was completed, the mixture was after-cured at 130 ° C. for 1 hour to obtain a grinding wheel of Comparative Example 1.
[0121]
(Grinding test)
A stainless steel round bar with a diameter of 25 mm was rotated at 322 / min with the central axis of the cross-sectional circle as the base axis, and the grindstone created in the examples and comparative examples was rotated at a peripheral speed of 1,800 m / min. It was brought into contact with a rotating stainless steel round bar at a pressure of 0.08 MPa. Grinding fluid (alkaline aqueous solution) was supplied to the contact portion between the stainless steel round bar and the grindstone, and grinding was performed for 15 minutes.
[0122]
Grinding amount
After grinding for 15 minutes, the stainless steel round bar was dried, and its mass reduction was measured to obtain the grinding amount. The grindstone of Examples 1 to 8 was a grindstone that had a larger amount of grinding than the grindstone of Comparative Example 1 and could be shaved well. The results are shown in Table 1.
[0123]
Current value
The current value required for grinding by rotating the grindstone at a constant peripheral speed (1800 m / min) was read at the time of 5 minutes and 10 minutes from the start of grinding in a grinding process of 15 minutes. The current value here is the value of the current supplied to the electric motor for rotating the grindstone. Actually, in an electric circuit for supplying electricity to the motor, an ammeter was installed in series with the motor to read the current value. The current value read in this way serves as an index of the driving force of the motor necessary for rotating the grindstone at a constant peripheral speed, and the grindstone having a larger grinding resistance requires a larger driving force and the current value increases. The grindstones of Examples 1 to 8 all had lower current values than the grindstone of Comparative Example 1. Therefore, the grindstones of Examples 1 to 8 are grindstones having low grinding resistance. The results are shown in Table 1.
[0124]
[Table 1]

[0125]
【The invention's effect】
According to the present invention, a grindstone comprising a resin composition for a grindstone containing a compound (A) having a specific structure and an unsaturated polyester resin and / or vinyl ester resin as a raw material has a low grinding resistance. Since the heat generation is small, a grindstone capable of grinding and polishing with high grinding accuracy can be provided.

Claims (18)

A resin composition for a grindstone comprising (A) and (B) shown below.
(A) a compound having at least one group represented by general formula (1) as a terminal group and a group represented by general formula (2) as a repeating unit (hereinafter also referred to as “compound (A)”) I will write.)
(B) Unsaturated polyester resin and / or vinyl ester resin (hereinafter also referred to as “compound (B)”)
General formula (1)

(In the general formula (1), each X ¹ independently represents an organic residue derived from a polyvalent carboxylic acid having 2 to 3 carboxylic acid groups, and at least one of the polyvalent carboxylic acids is Itaconic acid or maleic acid In general formula (1), n is 1 or 2, and when X ¹ has 2 carboxylic acid groups, n becomes 1 and X ¹ has 3 carboxylic acids. In the case of having a group, n is 2. In general formula (1), Y ¹ represents an alkyl group, an allyl group, or a methallyl group, provided that Y ¹ present in one molecule of compound (A) At least one must be an allyl group or a methallyl group.)
General formula (2)

(In the general formula (2), X ² each independently represents an organic residue derived from a polyvalent carboxylic acid having 2 to 3 carboxylic acid groups, and at least one of the polyvalent carboxylic acids is Itaconic acid or maleic acid In general formula (2), m is 1 or 2, and when X ² has 2 carboxylic acid groups, m becomes 1 and X ² has 3 carboxylic acids. In the case of having a group, m is 2. In general formula (2), Y ² is an organic residue derived from a polyhydric alcohol having 2 to 20 hydroxyl groups and having 2 to 6 hydroxyl groups. However, Y ² can have a branched structure having the above general formula (1) as a terminal group and the above general formula (2) as a repeating unit by an ester bond. In addition to (A) and (B) shown below, (C) a reactive diluent having polymerizability is further included, and a resin composition for a grindstone is characterized in that
(A) a compound having at least one group represented by general formula (1) as a terminal group and a group represented by general formula (2) as a repeating unit (hereinafter also referred to as “compound (A)”) I will write.)
(B) Unsaturated polyester resin and / or vinyl ester resin (hereinafter also referred to as “compound (B)”)
General formula (1)

(In the general formula (1), each X ¹ independently represents an organic residue derived from a polyvalent carboxylic acid having 2 to 3 carboxylic acid groups, and at least one of the polyvalent carboxylic acids is Itaconic acid or maleic acid In general formula (1), n is 1 or 2, and when X ¹ has 2 carboxylic acid groups, n becomes 1 and X ¹ has 3 carboxylic acids. In the case of having a group, n is 2. In general formula (1), Y ¹ represents an alkyl group, an allyl group, or a methallyl group, provided that Y ¹ present in one molecule of compound (A) At least one must be an allyl group or a methallyl group.)
General formula (2)

(In the general formula (2), X ² each independently represents an organic residue derived from a polyvalent carboxylic acid having 2 to 3 carboxylic acid groups, and at least one of the polyvalent carboxylic acids is Itaconic acid or maleic acid In general formula (2), m is 1 or 2, and when X ² has 2 carboxylic acid groups, m becomes 1 and X ² has 3 carboxylic acids. In the case of having a group, m is 2. In general formula (2), Y ² is an organic residue derived from a polyhydric alcohol having 2 to 20 hydroxyl groups and having 2 to 6 hydroxyl groups. However, Y ² can have a branched structure having the above general formula (1) as a terminal group and the above general formula (2) as a repeating unit by an ester bond. The grindstone according to claim 1, wherein (A) shown below is contained in a range of 1% by mass to 99% by mass, and (B) is contained in a range of 1% by mass to 99% by mass. Resin composition.
(A) Compound (B) unsaturated polyester resin having at least one group represented by the following general formula (1) as a terminal group and a group represented by the following general formula (2) as a repeating unit; / Or vinyl ester resin general formula (1)

(In the general formula (1), each X ¹ independently represents an organic residue derived from a polyvalent carboxylic acid having 2 to 3 carboxylic acid groups, and at least one of the polyvalent carboxylic acids is Itaconic acid or maleic acid In general formula (1), n is 1 or 2, and when X ¹ has 2 carboxylic acid groups, n becomes 1 and X ¹ has 3 carboxylic acids. In the case of having a group, n is 2. In general formula (1), Y ¹ represents an alkyl group, an allyl group, or a methallyl group, provided that Y ¹ present in one molecule of compound (A) At least one must be an allyl group or a methallyl group.)
General formula (2)

(In the general formula (2), X ² each independently represents an organic residue derived from a polyvalent carboxylic acid having 2 to 3 carboxylic acid groups, and at least one of the polyvalent carboxylic acids is Itaconic acid or maleic acid In general formula (2), m is 1 or 2, and when X ² has 2 carboxylic acid groups, m becomes 1 and X ² has 3 carboxylic acids. In the case of having a group, m is 2. In general formula (2), Y ² is an organic residue derived from a polyhydric alcohol having 2 to 20 hydroxyl groups and having 2 to 6 hydroxyl groups. However, Y ² can have a branched structure having the above general formula (1) as a terminal group and the above general formula (2) as a repeating unit by an ester bond. The following (A) is contained in the range of 1% by mass to 99% by mass, (B) in the range of 1% by mass to 99% by mass, and (C) in the range of 0% by mass to 50% by mass. The resin composition for a grindstone according to any one of claims 1 to 3.
(A) Compound (B) unsaturated polyester resin having at least one group represented by the following general formula (1) as a terminal group and a group represented by the following general formula (2) as a repeating unit; // Reactive diluent with vinyl ester resin (C) polymerizable general formula (1)

(In the general formula (1), each X ¹ independently represents an organic residue derived from a polyvalent carboxylic acid having 2 to 3 carboxylic acid groups, and at least one of the polyvalent carboxylic acids is Itaconic acid or maleic acid In general formula (1), n is 1 or 2, and when X ¹ has 2 carboxylic acid groups, n becomes 1 and X ¹ has 3 carboxylic acids. In the case of having a group, n is 2. In general formula (1), Y ¹ represents an alkyl group, an allyl group, or a methallyl group, provided that Y ¹ present in one molecule of compound (A) At least one must be an allyl group or a methallyl group.)
General formula (2)

(In the general formula (2), X ² each independently represents an organic residue derived from a polyvalent carboxylic acid having 2 to 3 carboxylic acid groups, and at least one of the polyvalent carboxylic acids is Itaconic acid or maleic acid In general formula (2), m is 1 or 2, and when X ² has 2 carboxylic acid groups, m becomes 1 and X ² has 3 carboxylic acids. In the case of having a group, m is 2. In general formula (2), Y ² is an organic residue derived from a polyhydric alcohol having 2 to 20 hydroxyl groups and having 2 to 6 hydroxyl groups. However, Y ² can have a branched structure having the above general formula (1) as a terminal group and the above general formula (2) as a repeating unit by an ester bond. (C) a reactive diluent having polymerizability, vinyl compounds, allyl compounds, and according to any one of claims 2 to 4, characterized in that the one selected from the group consisting of mixtures A resin composition for a grindstone. A method for producing a grindstone, comprising mixing abrasive grains with the resin composition for a grindstone according to any one of claims 1 to 5 and then curing the mixture using a radical polymerization initiator. The grinding wheel resin composition according to any one of claims 1 to 5 , wherein the abrasive grains and the pore material and / or the foaming agent are mixed and then cured using a radical polymerization initiator. Method. Claim, characterized in that cured using a radical polymerization initiator after adjusting the abrasive content to be in the range of 10 wt% to 80 wt% based on the total weight of the grinding wheel 6 or claim 7 The manufacturing method of the grindstone in any one of. Any abrasive grain alumina abrasive grains, silicon carbide abrasive grains and cubic boron nitride predisposition abrasive grains of claims 6 to claim 8, characterized in that at least one selected from the group consisting of diamond abrasive grains The manufacturing method of the grindstone of crab. The method for producing a grindstone according to any one of claims 7 to 9 , wherein the pore material has a diameter in a range of 50 µm to 300 µm. The foaming agent is a kind selected from the group consisting of an azo compound, a nitroso compound, a sulfonyl hydrazide compound, and a mixture of two or more of these, The production of the grindstone according to any one of claims 7 to 10. Method. The radical polymerization initiator is a kind selected from the group consisting of t-butyl peroxybenzoate, cumene hydroperoxide, and a mixture thereof. The grindstone according to any one of claims 6 to 11 , Production method. The method for producing a grindstone according to any one of claims 6 to 12 , wherein a redox accelerator is added to the radical polymerization initiator and then cured. The method for producing a grindstone according to claim 13 , wherein the redox accelerator is one selected from the group consisting of a cobalt carboxylate, a copper carboxylate, and a mixture thereof. The method for producing a grindstone according to claim 13 , wherein the redox accelerator is cobalt naphthenate. Method for producing a grinding stone according to any of claims 6 to claim 15, characterized in that the curing at room temperature. A grindstone manufactured by the manufacturing method according to any one of claims 6 to 16 . Stainless steel alloy, characterized in that it is manufactured by the manufacturing method according to any one of claims 6 to claim 16, aluminum metal and grinding and / or grinding wheel for grinding of the alloy or nickel alloy.