JP2004307691A - Curable silicone release agent composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a curable non-solvent type silicone release agent composition showing no silicone migration and having a small release resistance. <P>SOLUTION: The curable silicone release agent composition contains the following (A), (B), and (C) as essential components and does not contain an organic solvent whose viscosity at 25°C is within the range of 50-1,000 mPa×s. The (A) is 100 pts.wt. of a diorganopolysiloxane having an alkenyl group bonded to a silicon atom, represented by an average composition formula: (R<SP>1</SP>R<SB>2</SB>SiO<SB>1/2</SB>)<SB>a</SB>(R<SB>3</SB>SiO<SB>1/2</SB>)<SB>2-a</SB>(R<SP>1</SP>RSiO<SB>2/2</SB>)<SB>b</SB>(R<SB>2</SB>SiO<SB>2/2</SB>)<SB>c</SB>(wherein R<SP>1</SP>is an alkenyl group, R is an identical or different organic group having no alkenyl group; 1.3≤a≤1.8; 0.02≤b≤0.5; and 1.6≤a+b≤1.9). The (B) is 0.5-15.0 pts.wt. of an organohydrogenpolysiloxane having at least three hydrogen atoms combined with a silicon atom in one molecule, and the (C) is a catalytic amount of a catalyst belonging to platinum group metals. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００１１】
以下、本発明につき更に詳しく説明する。
本発明の（Ａ）成分のオルガノポリシロキサンは本発明で主成分となるアルケニル基含有ジオルガノポリシロキサンであり、分子鎖末端に平均して１．３〜１．８個、側鎖に平均して０．０２〜０．５個、全体の合計として１分子中に１．６〜１．９個の範囲でケイ素原子に結合したアルケニル基を有するジオルガノポリシロキサンである。末端及び側鎖のアルケニル基の合計が１．６未満では硬化性が低下するのに加えシリコーン移行の問題が生じ、１．９を超えると剥離抵抗が小さいという本発明の効果が得られない。
【００１２】
ここで、アルケニル基としては炭素数２〜１０のアルケニル基であり，具体的にはビニル基，アリル基，ブテニル基、プロペニル基，５−ヘキセニル基，オクテニル基，デセニル基，等が例示される。好ましくはビニル基である。
【００１３】
Ｒで示されるアルケニル基を含有しない有機基としては、置換もしくは非置換の一価炭化水素基が挙げられ、一価炭化水素基としては炭素数１〜１６のもの特に炭素数１〜８のものが好ましく、メチル基、エチル基、プロピル基、ブチル基、オクチル基等のアルキル基、シクロヘキシル基等のシクロアルキル基、トリル基等のアリール基、ベンジル基、フェネチル基等のアラルキル基などが挙げられ、またこれらの水素原子の一部または全部をハロゲン原子などで置換したクロロプロピル基、トリフルオロプロピル基等のハロアルキル基が挙げられるが、硬化性、剥離性向上の点から８０モル％以上がメチル基であることが好ましい。
【００１４】
更に、２５℃における粘度は５０〜１０００ｍＰａ・ｓの範囲内である。５０ｍＰａ・ｓより低いと基材への染み込みが多くなるという不具合が生じ、１，０００ｍＰａ・ｓより高い場合は塗工性が低下し高速塗工におけるミスト発生の問題が生じるためである。
【００１５】
このオルガノポリシロキサンは下記構造式（２）
【化２】

（ここでＲ^１はアルケニル基、Ｒはアルケニル基を含有しない同種又は異種の一価炭化水素基であり，Ｘ，Ｙはそれぞれ０または１でありＸ＋Ｙの合計は平均して１．３〜１．８であり、ｍは０または１〜３の整数をとるが平均すると０．０２〜０．５であり、Ｘ＋Ｙ＋ｍの合計は平均しして１．６〜１．９であり、３５≦ｎ≦２５０）で示された２５℃における粘度が５０〜１０００ｍＰａ・ｓであるものが例示される。
【００１６】
このオルガノポリシロキサンの合成法としては例えば、分子鎖末端及び側鎖のけい素原子に結合したビニル基を含有するオルガノポリシロキサンとけい素原子に結合したビニル基を含有しないオルガノポリシロキサンの混合物を、またはヘキサメチルジシロキサン、１，３−ジビニル−１，１，３，３テトラメチルジシロキサンのような末端ストッパーとオクタメチルシクロテトラシロキサン、１，３，５，７−テトラメチル−１，３，５，７−テトラビニルシクロテトラシロキサンのような環状シロキサンを目標組成になるように任意にそれぞれ配合し、ＫＯＨのようなアルカリ重合触媒を用い常法に従ってそれぞれ合成することができる。
【００１７】
（Ｂ）成分のオルガノハイドロジェンポリシロキサンは（Ａ）成分に対し架橋剤として機能するもので、ケイ素原子に直接結合している水素原子が（ＳｉＨ基）、（Ａ）成分中のアルケニル基とヒドロシリル化反応により硬化する。（Ｂ）成分オルガノハイドロジェンポリシロキサンは、１分中にけい素原子に結合した水素原子を少なくとも３個以上有し、このＳｉＨ基と（Ａ）成分中のアルケニル基とが付加反応して硬化皮膜が形成されるものでる。
【００１８】
かかる（Ｂ）成分としては、下記構造式（３）
Ｒ_ｅＨ_ｄＳｉＯ_{（４−ｅ−ｄ）／２} （３）
（ここでＲは上記したと同様のアルケニル基を含有しない有機基であり、ｅ，ｄはそれぞれｅ＋ｄ≦３を満たす正数で有る。）で示される２５℃における粘度が２〜１０００ｍＰａ・ｓのものである。
【００１９】
この種のポリシロキサンとしては、（ＣＨ_３）ＨＳｉＯ_２／２単位，ＨＳｉＯ_３／２単位，（ＣＨ_３）_２ＳｉＯ_２／２単位，（ＣＨ_３）_２ＨＳｉＯ_１／２単位，（ＣＨ_３）ＳｉＯ_３／２単位，（ＣＨ_３）_３ＳｉＯ_１／２単位から成るポリマ−またはコポリマ−が例示されるが、ＲＨＳｉＯ_２／２単位またはＲ_２ＨＳｉＯ_１／２単位をを合計して１分子中に少なくとも３個有すものである。これは直鎖状、環状のいづれであってもよく、２５℃における粘度が２〜１０００ｍＰａ・ｓのものとすればよい。
【００２０】
また、（Ｂ）成分の配合量は（Ａ）成分１００重量部に対して０．５〜１５．０重量部とされるが、（Ａ）成分のアルケニル基量に対する、ケイ素に直接結合している水素原子の量によって調整されるものでありモル比で１．０〜５．０の範囲とされる。モル比で１．０より小さいと硬化性が低下し５．０より大きいと剥離抵抗が大きくなり実用的な剥離特性が得られない。
【００２１】
ここで、上記Ｒとしては上記したと同様の基が例示されるが、メチル基，エチル基，プロピル基等のアルキル基、フェニル基，トリル基等のアリール基などが好ましく、付加反応速度の向上の点からメチル基であることがさらに好ましい。
【００２２】
（Ｃ）成分の白金族金属系触媒は、（Ａ）成分と（Ｂ）との付加反応を促進するための触媒であり、付加反応触媒として公知のものが使用できる。このような白金族金属系触媒としては、例えば白金系、パラジウム系、ロジウム系などの触媒が挙げられ、これらの中で特に白金系触媒が好ましい。このような白金系触媒としては、例えば塩化白金酸、塩化白金酸のアルコール溶液やアルデヒド溶液、塩化白金酸の各種オレフィン又はビニルシロキサンとの錯体などが挙げられる。
【００２３】
これら白金族金属系触媒の添加量は触媒量であるが、良好な硬化皮膜を得ると共に経済的な見地から、（Ａ）成分１００重量部に対して白金族金属量として１〜１，０００ｐｐｍの範囲とすることが好ましい。
【００２４】
本発明の組成物には、上記（Ａ）〜（Ｃ）成分の所定量を配合することによって得られるが、以上の各成分の外に、他の任意成分、例えば白金族金属系触媒の触媒活性を抑制する目的で、各種有機窒素化合物、有機りん化合物、アセチレン系化合物、オキシム化合物、有機クロロ化合物などの活性抑制剤などを必要に応じて添加することができる。なお、任意成分の添加量は本発明の効果を妨げない範囲で通常量とすることができる。
【００２５】
本発明のシリコーン組成物の調製に際しては、（Ａ），（Ｂ）成分及び任意成分を予め均一に混合した後、（Ｃ）成分を添加することが好ましく、各成分は単一で使用しても２種以上を併用してもよい。ただし、組成物全体としての２５℃における粘度は５０〜１０００ｍＰａ・ｓの範囲内とされ、１０００ｍＰａ・ｓを越えると塗工時における塗工ロール間から発生するミストのため高速塗工出来ず生産性が低下するため実用上の使用困難となる。
【００２６】
このようにして調製されたシリコーン組成物は、例えば紙、プラスチックフィルムなどの基材に塗布した後、常法によって加熱硬化される。本発明の組成物の硬化皮膜が形成された基材は剥離紙などとして好適に使用される。
【００２７】
さらに、本発明の組成物を均一に薄く塗工する場合に有機溶剤を配合することが有利である。有機溶剤は、組成物塗工の作業性などを考慮してその種類及び配合量を調製することができる。有機溶剤としては、例えばトルエン、キシレン、ベンゼン、ヘプタン、ヘキサン、トリクロルエチレン、パークロロエチレン、塩化メチレン、酢酸エチル、溶剤揮発油，アセトン，メチルエチルケトン，ＭＩＢＫ等が挙げられ、プライマー組成物のフィルム基材への濡れ性などに応じて一種または二種以上を組み合わせて混合溶剤として用いてもよい。
【００２８】
本発明のシリコーン組成物は前記成分を均一に混合し、例えば紙、プラスチックスフィルム等の基材にに均一に塗布後，加熱硬化を行うことにより使用する。塗布量は、基材表面に硬化被膜を形成させるのに十分な量とすればよく、例えば０．１から５ｇ／ｍ^２程度であり、多量の塗布によっても剥離性能の向上は頭打ちとなるので、経済的な観点からコストアップになるので好ましくない。その後、加熱硬化を行う。加熱硬化時の温度はフィルム種や塗工量によっても異なるが、１００℃で１０秒から１８０℃で６０秒程度の範囲で適宜使用すれば良い。
【００２９】
【発明の効果】
本発明のシリコーン組成物は薄膜塗工性に優れるものであり、（Ａ）成分のアルケニル基が分子鎖末端に加え側鎖にもあるため、アルケニル基が１分子中に平均して１．６〜１．９個の範囲内であっても、硬化皮膜のシリコーン移行がなく、しかも剥離抵抗が小さいという本発明の効果が得ら得られるのもである。
【００３０】
【実施例】
以下、実施例及び比較例を示し、本発明を具体的に説明するが、本発明は下記の実施例に制限されるものではない。なお下記の例において部はいずれも重量部であり、粘度は２５℃における値である。
【００３１】
また、シリコーン組成物の硬化性、剥離力、残留接着率、シリコーン移行性は下記の方法により測定した。
【００３２】
硬化性
シリコーン組成物を薄膜状フィルム又はシート状の基材表面に所定量塗布し、所定温度の熱風式乾燥機中で加熱して形成される硬化皮膜を指で数回こすり、くもり及び脱落のない状態になるまでの時間（秒数）を測定した。
【００３３】
剥離力
シリコーン組成物を薄膜状フィルム又はシート状の基材表面に所定量塗布し、所定温度の熱風式乾燥機中で加熱して硬化皮膜を成形した後、２５℃で１日セパレ−タ−エ−ジング後、この硬化皮膜表面にアクリル系溶剤型粘着剤・オリバインＢＰＳ−５１２７（東洋インキ製造株式会社製）をＷｅｔで１３０μｍ塗布して１００℃で３分間加熱処理した。次に、この処理面に坪量６４ｇ／ｍ^２の上質紙を貼り合わせ、２５℃で２０時間エイジングさせた後、試料を５０ｍｍ幅に切断し、１８０度の角度で剥離速度０．３ｍ／分で貼り合わせ紙を引張り、剥離するのに要する力（Ｎ）を引張り試験機（株式会社島津製作所製ＡＧＳ−５０Ｇ型）を用いて測定した。
【００３４】
残留接着率
剥離力測定の場合と同様にして基材表面に形成されたシリコーン組成物の硬化皮膜の表面にポリエステルテープ（商品名：Ｎｏ．３１Ｂテ−プ、日東電工株式会社製）を貼り合わせ、１．９６ＫＰａの荷重を載せて７０℃で２０時間エイジングした後、テープを剥がしてステンレン板に貼り付けた。次に、このテープをステンレス板から１８０度の角度で剥離速度０．３ｍ／分で剥がし、剥離するのに要する力：Ａ（Ｎ）を測定した。また、ブランクとしてポリエステルテープを巾１２ｃｍ×長さ２５ｃｍ×厚さ３ｍｍのテフロン（登録商標：デュポン社製商品名）の板に貼り合わせ、同様に処理したテープをステンレス板から剥離するのに要する力：Ｂ（Ｎ）を測定し、（Ａ／Ｂ）×１００により、残留接着率（％）とした。
【００３５】
シリコーン移行性
剥離力測定の場合と同様にして基材表面に形成されたシリコーン組成物の硬化皮膜の表面に３６μｍのＰＥＴフィルムを重ね室温で０．９８ＭＰａで２０時間圧着した後、シリコーン塗工面に接した側のＰＥＴフィルム面に油性のインキ（商品名：マジックインキ、寺西化学工業株式会社製）を塗布し、そのハジキ具合により、インキのハジキなし：○、インキのハジキあり：×としてシリコーンの移行を評価した。
【００３６】
［実施例］
（２）式においてＲ^１がビニル基，Ｒがメチル基である下記式（４）で示されるシロキサンの合成を行った。
【化３】

【００３７】
［実施例１］オルガノポリシロキサン−Ａの合成
ヘキサメチルジシロキサン０．２ｍｏｌ、１，３−ジビニル−１，１，３，３−テトラメチルジシロキサン０．８ｍｏｌ、オクタメチルシクロテトラシロキサン２８．７５ｍｏｌ、１，３，５，７−テトラメチル−１，３，５，７−テトラビニルシクロテトラシロキサン０．０２５ｍｏｌに水酸化カリウムのシリコネート をＳｉ／Ｋ＝２００００／１（モル比）量加え窒素雰囲気下で１５０℃／６時間平衡化反応させた後、エチレンクロロヒドリンをＫに対して２ｍｏｌ量添加し１２０℃／２時間中和した。その後、１６０℃，１３００Ｐａ（１０ｍｍＨｇ）の減圧度で６時間加熱バブリング処理し揮発分をカットして粘度が２１５ｍＰａ・ｓである、上記式（４）においてＸ＋Ｙの合計の平均が１．６、ｍの平均が０．１、ｎ＝１１５となるオルガノポリシロキサン−Ａを得た。
次ぎに（Ａ）成分として上記で得られたオルガノポリシロキサン−Ａ１００部、（Ｂ）成分として分子鎖両末端がトリメチルシロキシ基で封鎖された粘度が２０ｍＰａ・ｓであるメチルハイドロジェンポリシロキサン２．４７部（ＳｉＨ／ＳｉＣＨ＝ＣＨ_２＝１．８）、更に任意成分として１−エチニル−１−シクロヘキサノ−ル０．３部を加え、均一になるまで攪拌した後、（Ｃ）成分として白金とビニルシロキサンとの錯体を上記（Ａ）と（Ｂ）の合計に対して白金換算で１００ｐｐｍになるように添加し、粘度が２０５ｍＰａ・ｓであるシリコーン組成物を調製した。
【００３８】
次に、得られたシリコーン組成物をポリエチレンラミネート紙（坪量１００ｇ／ｍ^２）に０．６〜０．７ｇ／ｍ^２で塗布し、キュアー性試験として、１２０℃で硬化するまでの時間（秒数）をもとめた。また剥離力、残留接着率用サンプルとしては１４０℃で３０秒間加熱処理して硬化皮膜を形成させた。これらの測定結果を表１に示す。
【００３９】
［実施例２］オルガノポリシロキサン−Ｂの合成
ヘキサメチルジシロキサン０．３ｍｏｌ、１，３−ジビニル−１，１，３，３−テトラメチルジシロキサン０．７ｍｏｌ、オクタメチルシクロテトラシロキサン ２８．７５ｍｏｌ、１，３，５，７−テトラメチル−１，３，５，７−テトラビニルシクロテトラシロキサン０．０７５ｍｏｌとした以外は、実施例１と同様に合成反応を行って、上記式（４）においてＸ＋Ｙの合計の平均が１．４、ｍの平均が０．３、ｎ＝１１５で粘度が２１６ｍＰａ．ｓである、オルガノポリシロキサン−Ｂを得た。
【００４０】
次ぎに、（Ａ）成分として上記で得られたポリジメチルシロキサン−Ｂ１００部、（Ｂ）成分として分子鎖両末端がトリメチルシロキシ基で封鎖された粘度が２０ｍＰａ・ｓであるメチルハイドロジェンポリシロキサン２．２２部（ＳｉＨ／ＳｉＣＨ＝ＣＨ_２＝１．８）、更に任意成分として１−エチニル−１−シクロヘキサノ−ル０．３部を加え、均一になるまで攪拌した後、（Ｃ）成分として白金とビニルシロキサンとの錯体を上記（Ａ）と（Ｂ）の合計に対して白金換算で１００ｐｐｍになるように添加し、粘度が２００ｍＰａ・ｓであるシリコーン組成物を調製し、実施例１と同様の物性試験を行った。結果を表１に併記する。
【００４１】
［実施例３］オルガノポリシロキサン−Ｃの合成
ヘキサメチルジシロキサン０．１ｍｏｌ、１，３−ジビニル−１，１，３，３−テトラメチルジシロキサン０．９ｍｏｌ、オクタメチルシクロテトラシロキサン３７．５ｍｏｌ、１，３，５，７−テトラメチル−１，３，５，７−テトラビニルシクロテトラシロキサン ０．０１２５ｍｏｌとした以外は、実施例１と同様に合成反応を行って、上記式（４）においてＸ＋Ｙの合計の平均が１．８、ｍの平均が０．０５、ｎ＝１５０で粘度が４１０ｍＰａ・ｓである、オルガノポリシロキサン−Ｃを得た。
【００４２】
次に、（Ａ）成分として上記で得られたポリジメチルシロキサン−Ｃ１００部、（Ｂ）成分として分子鎖両末端がトリメチルシロキシ基で封鎖された粘度が２０ｍＰａ．ｓであるメチルハイドロジェンポリシロキサン２．０部（ＳｉＨ／ＳｉＣＨ＝ＣＨ_２＝１．８）、更に任意成分として１−エチニル−１−シクロヘキサノ−ル０．３部を加え、均一になるまで攪拌した後、（Ｃ）成分として白金とビニルシロキサンとの錯体を上記（Ａ）と（Ｂ）の合計に対して白金換算で１００ｐｐｍになるように添加し、粘度が３８０ｍＰａ・ｓであるシリコーン組成物を調製し、実施例１と同様の物性試験を行った。結果を表１に併記する。
【００４３】
［比較例１］
（Ａ）成分として分子鎖両末端がジメチルビニルシロキシ基で封鎖された粘度が２１０ｍＰａ・ｓであるポリジメチルシロキサン−Ｄ１００部、（Ｂ）成分として分子鎖両末端がトリメチルシロキシ基で封鎖された粘度が２０ｍＰａ・ｓであるメチルハイドロジェンポリシロキサン２．９部（ＳｉＨ／ＳｉＣＨ＝ＣＨ_２＝１．８）、更に任意成分として１−エチニル−１−シクロヘキサノ−ル０．３部を加え、均一になるまで攪拌した後、（Ｃ）成分として白金とビニルシロキサンとの錯体を上記（Ａ）と（Ｂ）の合計に対して白金換算で１００ｐｐｍになるように添加し、粘度が１９５ｍＰａ・ｓであるシリコーン組成物を調製し、実施例１と同様の物性試験を行った。結果を表１に併記する。
【００４４】
［比較例２］オルガノポリシロキサン−Ｅの合成
１，３，５，７−テトラメチル−１，３，５，７−テトラビニルシクロテトラシロキサンを使用しなかった以外は、実施例１と同様に合成反応を行って、上記式（４）においてＸ＋Ｙの合計の平均が１．６、ｍの平均が０、ｎ＝１１５で粘度が２１０ｍＰａ・ｓである、オルガノポリシロキサン−Ｅを得た。
【００４５】
次に、（Ａ）成分として上記で得られたポリジメチルシロキサン−Ｅ１００部、（Ｂ）成分として分子鎖両末端がトリメチルシロキシ基で封鎖された粘度が２０ｍＰａ・ｓであるメチルハイドロジェンポリシロキサン２．１４部（ＳｉＨ／ＳｉＣＨ＝ＣＨ_２＝１．８）、更に任意成分として１−エチニル−１−シクロヘキサノ−ル０．３部を加え、均一になるまで攪拌した後、（Ｃ）成分として白金とビニルシロキサンとの錯体を上記（Ａ）と（Ｂ）の合計に対して白金換算で１００ｐｐｍになるように添加し、粘度が２００ｍＰａ・ｓであるシリコーン組成物を調製し、実施例１と同様の物性試験を行った。結果を表１に併記する。
【００４６】
［比較例３］
（Ａ）成分として分子鎖両末端がジメチルビニルシロキシ基で封鎖された粘度が２１０ｍＰａ・ｓであるポリジメチルシロキサン−Ｆ８５部及び分子鎖両末端がトリメチルシロキシ基で封鎖された粘度が２００ｍＰａ・ｓであるポリジメチルシロキサン−Ｇ１５部、（Ｂ）成分として分子鎖両末端がトリメチルシロキシ基で封鎖された粘度が２０ｍＰａ・ｓであるメチルハイドロジェンポリシロキサン２．１部（ＳｉＨ／ＳｉＣＨ＝ＣＨ_２＝１．８）、更に任意成分として１−エチニル−１−シクロヘキサノ−ル０．３部を加え、均一になるまで攪拌した後、（Ｃ）成分として白金とビニルシロキサンとの錯体を上記（Ａ）と（Ｂ）の合計に対して白金換算で１００ｐｐｍになるように添加し、粘度が１９３ｍＰａ・ｓであるシリコーン組成物を調製し、実施例１と同様の物性試験を行った。結果を表２に併記する。
【００４７】
【表１】（Ａ）成分シロキサンの構造

【表２】

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides an addition-reaction-type solvent-free silicone release agent composition that has excellent thin film coating properties, does not transfer silicone, and provides a release silicone cured film having a small peel resistance, and a cured film of this composition. It relates to the formed release paper.
[0002]
Problems to be solved by the prior art and the invention
Conventionally, for the purpose of preventing adhesion or sticking between a base material such as paper or plastic film and an adhesive substance, it is possible to form a cured film of a silicone composition on the base material surface and impart releasability. Is being done.
[0003]
In this case, as a method of forming a silicone film on the substrate surface,
(1) A method in which an organopolysiloxane containing an alkenyl group and an organohydrogenpolysiloxane are subjected to an addition reaction using a platinum compound as a catalyst to form a peelable film (see, for example, JP-A-47-32072). (2) A method of forming a peelable film by condensing an organopolysiloxane using an organic acid metal salt catalyst such as an organotin compound (see, for example, JP-A-35-13709). A method of forming a peelable film using an organopolysiloxane containing a group and a photoinitiator using ultraviolet rays (see, for example, JP-A-55-104320). A method of curing with a wire (for example, see JP-A-54-162787) is known.
The properties are classified into a type dissolved in an organic solvent such as toluene, an emulsion type in which these are emulsified, and a non-solvent type consisting only of silicone.
Among these silicone films, the addition-reaction type (1), which has excellent curability and can meet various peeling characteristics at low speed and high speed, is widely used. From the viewpoint of safety and hygiene, conversion from solvent type to non-solvent type is progressing. In addition, high-speed coating is required in terms of productivity, and from the viewpoint of leveling properties and prevention of mist generation, there is no silicone transfer with a lower viscosity solventless type, and there is no decrease in adhesive strength of the adhesive. There is a demand for a solventless type having a small peel resistance.
As a method for reducing the peeling resistance, for example, addition of an organopolysiloxane having no alkenyl group or hydrogen atom bonded to a silicon atom is known. In this case, in addition to an increase in silicone migration, Disadvantages such as a decrease in coatability due to an increase in the viscosity of the composition occur. Japanese Patent Publication No. 3-52498 discloses the addition of a relatively small amount of a phenyl group-containing polysiloxane. However, in this case as well, although the peeling resistance is reduced, there is a disadvantage that the adhesive strength of the pressure-sensitive adhesive is significantly reduced due to the phenyl group-containing polysiloxane transferred to the pressure-sensitive adhesive surface.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a curable, solventless silicone release agent composition having no silicone migration and low peel resistance.
[0008]
[Patent Document 1]
Japanese Patent Publication No. 3-52498 [Patent Document 2]
JP 2000-510517 A
[Problems to be solved by the invention]
The present inventor has conducted intensive studies on the amount of alkenyl groups of the alkenyl group-containing diorganopolysiloxane which is the main component in order to achieve the above object, and as a result, the average of the total molecular chain terminals is 1.3 to 1.8. Diorgano having an alkenyl group bonded to a silicon atom in an amount of from 0.02 to 0.5 on the side chain and from 1.6 to 1.9 on the average in one molecule as a whole. The present inventors have found that the use of polysiloxane has excellent thin film coating properties, does not cause silicone migration, and can reduce the peeling resistance, and has accomplished the present invention.
[0010]
Means for Solving the Problems and Embodiments of the Invention
The inventor has made intensive efforts to achieve the above object,

[0011]
Hereinafter, the present invention will be described in more detail.
The organopolysiloxane of the component (A) of the present invention is an alkenyl group-containing diorganopolysiloxane as a main component in the present invention, and has an average of 1.3 to 1.8 at the molecular chain terminal and an average of the side chain. The diorganopolysiloxane has an alkenyl group bonded to a silicon atom in an amount of 0.02 to 0.5, and a total of 1.6 to 1.9 in one molecule. If the total of the terminal and side chain alkenyl groups is less than 1.6, the curability will be reduced and the problem of silicone migration will occur. If it exceeds 1.9, the effect of the present invention that peel resistance is small will not be obtained.
[0012]
Here, the alkenyl group is an alkenyl group having 2 to 10 carbon atoms, and specific examples thereof include a vinyl group, an allyl group, a butenyl group, a propenyl group, a 5-hexenyl group, an octenyl group, and a decenyl group. . Preferably it is a vinyl group.
[0013]
Examples of the organic group not containing an alkenyl group represented by R include substituted or unsubstituted monovalent hydrocarbon groups, and monovalent hydrocarbon groups having 1 to 16 carbon atoms, particularly those having 1 to 8 carbon atoms Preferred are an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group and an octyl group, a cycloalkyl group such as a cyclohexyl group, an aryl group such as a tolyl group, an aralkyl group such as a benzyl group and a phenethyl group. And a haloalkyl group such as a chloropropyl group or a trifluoropropyl group in which a part or all of these hydrogen atoms are substituted with a halogen atom or the like. It is preferably a group.
[0014]
Further, the viscosity at 25 ° C. is in the range of 50 to 1000 mPa · s. If the pressure is lower than 50 mPa · s, the problem of infiltration into the substrate increases, and if the pressure is higher than 1,000 mPa · s, the coating property is deteriorated and the problem of mist generation in high-speed coating occurs.
[0015]
This organopolysiloxane has the following structural formula (2)
Embedded image

(Where R ¹ is an alkenyl group, R is a same or different monovalent hydrocarbon group containing no alkenyl group, X and Y are each 0 or 1, and the sum of X + Y is 1.3 to 1 on average. M is an integer of 0 or 1 to 3, but is 0.02 to 0.5 on average, the sum of X + Y + m is 1.6 to 1.9 on average, and 35 ≦ n ≦ 250) having a viscosity at 25 ° C. of 50 to 1000 mPa · s.
[0016]
As a method for synthesizing this organopolysiloxane, for example, a mixture of an organopolysiloxane having a vinyl group bonded to a silicon atom at a molecular chain terminal and a side chain and an organopolysiloxane not containing a vinyl group bonded to a silicon atom, Or a terminal stopper such as hexamethyldisiloxane, 1,3-divinyl-1,1,3,3 tetramethyldisiloxane and octamethylcyclotetrasiloxane, 1,3,5,7-tetramethyl-1,3, Cyclic siloxanes such as 5,7-tetravinylcyclotetrasiloxane are arbitrarily compounded so as to have a target composition, and can be synthesized according to a conventional method using an alkali polymerization catalyst such as KOH.
[0017]
The organohydrogenpolysiloxane of the component (B) functions as a crosslinking agent for the component (A), and a hydrogen atom directly bonded to a silicon atom is a (SiH group) and an alkenyl group in the component (A) It is cured by a hydrosilylation reaction. The component (B) organohydrogenpolysiloxane has at least three hydrogen atoms bonded to a silicon atom in one minute, and is cured by an addition reaction between the SiH group and the alkenyl group in the component (A). A film is formed.
[0018]
As the component (B), the following structural formula (3)
_{R e H d SiO (4-} e-d) / 2 (3)
(Where R is an organic group that does not contain an alkenyl group as described above, and e and d are each a positive number satisfying e + d ≦ 3) and have a viscosity at 25 ° C. of 2 to 1000 mPa · s. Things.
[0019]
Examples of this type of polysiloxane include (CH ₃ ) HSiO _2/2 units, HSiO _3/2 units, (CH ₃ ) ₂ SiO _2/2 units, (CH ₃ ) ₂ HSiO _1/2 units, and (CH ₃ ) A polymer or a copolymer composed of SiO _3/2 units and (CH ₃ ) ₃ SiO _1/2 units is exemplified, and the total of RHSiO _2/2 units or R ₂ HSiO _1/2 units is one molecule. Has at least three. This may be linear or cyclic, and the viscosity at 25 ° C. may be 2 to 1000 mPa · s.
[0020]
Component (B) is added in an amount of 0.5 to 15.0 parts by weight per 100 parts by weight of component (A), but is directly bonded to silicon based on the alkenyl group content of component (A). It is adjusted by the amount of hydrogen atoms present and is in the range of 1.0 to 5.0 in molar ratio. If the molar ratio is less than 1.0, the curability decreases, and if the molar ratio is more than 5.0, the peel resistance increases and practical peel characteristics cannot be obtained.
[0021]
Here, R is exemplified by the same groups as described above, but is preferably an alkyl group such as a methyl group, an ethyl group, or a propyl group, or an aryl group such as a phenyl group or a tolyl group. In view of the above, a methyl group is more preferable.
[0022]
The platinum group metal catalyst as the component (C) is a catalyst for accelerating the addition reaction between the component (A) and the component (B), and any known addition reaction catalyst can be used. Examples of such platinum group metal-based catalysts include, for example, platinum-based, palladium-based, and rhodium-based catalysts, and among these, platinum-based catalysts are particularly preferred. Examples of such a platinum-based catalyst include chloroplatinic acid, an alcohol solution or aldehyde solution of chloroplatinic acid, and complexes of chloroplatinic acid with various olefins or vinylsiloxane.
[0023]
The amount of the platinum group metal-based catalyst added is a catalytic amount, but from the viewpoint of obtaining a good cured film and economical, 1 to 1,000 ppm of the platinum group metal based on 100 parts by weight of the component (A). It is preferable to set the range.
[0024]
The composition of the present invention can be obtained by blending a predetermined amount of the above components (A) to (C). In addition to the above components, other optional components, for example, a catalyst of a platinum group metal-based catalyst For the purpose of suppressing the activity, an activity inhibitor such as various organic nitrogen compounds, organic phosphorus compounds, acetylene compounds, oxime compounds and organic chloro compounds can be added as required. In addition, the addition amount of the optional component can be a normal amount within a range that does not impair the effects of the present invention.
[0025]
In preparing the silicone composition of the present invention, it is preferable to mix the components (A) and (B) and optional components beforehand and then add the component (C). May be used in combination of two or more. However, the viscosity at 25 ° C. of the whole composition is in the range of 50 to 1000 mPa · s, and if it exceeds 1000 mPa · s, high-speed coating cannot be performed due to mist generated between the coating rolls at the time of coating. Becomes practically difficult to use.
[0026]
The silicone composition thus prepared is applied to a substrate such as paper or plastic film and then cured by heating in a conventional manner. The substrate on which the cured film of the composition of the present invention is formed is suitably used as a release paper or the like.
[0027]
Furthermore, when the composition of the present invention is applied uniformly and thinly, it is advantageous to incorporate an organic solvent. The kind and amount of the organic solvent can be adjusted in consideration of the workability of coating the composition. Examples of the organic solvent include toluene, xylene, benzene, heptane, hexane, trichloroethylene, perchloroethylene, methylene chloride, ethyl acetate, solvent volatile oil, acetone, methyl ethyl ketone, MIBK, and the like. It may be used alone or in combination of two or more as a mixed solvent depending on the wettability to the surface.
[0028]
The silicone composition of the present invention is used by uniformly mixing the above-mentioned components, applying the mixture uniformly to a substrate such as paper or plastic film, and then performing heat curing. The amount of application may be an amount sufficient to form a cured film on the surface of the base material, for example, about 0.1 to 5 g / m ² . However, it is not preferable because the cost is increased from an economic viewpoint. Thereafter, heat curing is performed. The temperature at the time of heat curing varies depending on the type of film and the amount of coating, but may be appropriately used within a range of 10 seconds at 100 ° C. to about 60 seconds at 180 ° C.
[0029]
【The invention's effect】
The silicone composition of the present invention is excellent in coatability of a thin film. Since the alkenyl group of the component (A) is present not only at the molecular chain terminal but also at the side chain, the alkenyl group is 1.6 on average in one molecule. Even within the range of from 1.9 to 1.9, the effect of the present invention that the cured film does not migrate to silicone and the peel resistance is small can be obtained.
[0030]
【Example】
Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. In the following examples, all parts are parts by weight, and the viscosity is a value at 25 ° C.
[0031]
Further, the curability, peeling force, residual adhesiveness, and silicone transferability of the silicone composition were measured by the following methods.
[0032]
The curable <br/> silicone composition was applied predetermined amount a thin film or sheet substrate surface, rubbed several times a cured film formed by heating in a hot air dryer at a predetermined temperature with a finger, The time (seconds) until the state without clouding and falling off was measured.
[0033]
Peeling force A predetermined amount of the silicone composition is applied to the surface of a thin film or sheet-like substrate and heated in a hot air drier at a predetermined temperature to form a cured film, and then at 25 ° C for one day. After the separator aging, an acrylic solvent-type pressure-sensitive adhesive, Olivine BPS-5127 (manufactured by Toyo Ink Mfg. Co., Ltd.) was applied to the surface of the cured film at 130 μm by Wet and heat-treated at 100 ° C. for 3 minutes. Next, a high-quality paper having a basis weight of 64 g / m ² was bonded to the treated surface and aged at 25 ° C. for 20 hours. The force (N) required to pull and peel the bonded paper was measured using a tensile tester (AGS-50G manufactured by Shimadzu Corporation).
[0034]
Residual adhesion rate A polyester tape (trade name: No. 31B tape, manufactured by Nitto Denko Corporation) is applied to the surface of the cured film of the silicone composition formed on the substrate surface in the same manner as in the case of the peeling force measurement. ) And aged at 70 ° C. for 20 hours under a load of 1.96 KPa, and then the tape was peeled off and affixed to a stainless steel plate. Next, this tape was peeled off from the stainless steel plate at an angle of 180 degrees at a peeling speed of 0.3 m / min, and the force required for peeling: A (N) was measured. Further, a force required for bonding a polyester tape as a blank to a Teflon (registered trademark: trade name: manufactured by DuPont) plate having a width of 12 cm, a length of 25 cm and a thickness of 3 mm, and peeling the similarly treated tape from the stainless steel plate. : B (N) was measured, and the residual adhesion rate (%) was determined by (A / B) × 100.
[0035]
Silicone transferability A 36 μm PET film was layered on the surface of the cured film of the silicone composition formed on the substrate surface in the same manner as in the case of the peeling force measurement, and pressed at 0.98 MPa at room temperature for 20 hours. An oil-based ink (trade name: Magic Ink, manufactured by Teranishi Kagaku Kogyo Co., Ltd.) is applied to the PET film surface in contact with the silicone coating surface, and depending on the repelling condition, no ink repelling: ○, ink repelling: The transfer of silicone was evaluated as x.
[0036]
[Example]
A siloxane represented by the following formula (4) in which R ¹ is a vinyl group and R is a methyl group in the formula (2) was synthesized.
Embedded image

[0037]
[Example 1] Synthesis of organopolysiloxane-A 0.2 mol of hexamethyldisiloxane, 0.8 mol of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane, 28.75 mol of octamethylcyclotetrasiloxane , 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, 0.025 mol of potassium hydroxide siliconate in Si / K = 20,000 / 1 (molar ratio) and nitrogen atmosphere After equilibrating at 150 ° C. for 6 hours under the same conditions, ethylene chlorohydrin was added in an amount of 2 mol based on K and neutralized at 120 ° C. for 2 hours. Thereafter, a heating bubbling treatment is performed at 160 ° C. and a reduced pressure of 1300 Pa (10 mmHg) for 6 hours to remove volatile components, and the viscosity is 215 mPa · s. In the above formula (4), the average of the sum of X + Y is 1.6 m. Of 0.1 and n = 115 was obtained.
Next, 100 parts of the organopolysiloxane-A obtained above as the component (A), and methylhydrogenpolysiloxane having a viscosity of 20 mPa · s in which both ends of the molecular chain are blocked with trimethylsiloxy groups as the component (B). 47 parts (SiH / SiCH = CH ₂ = 1.8) and 0.3 part of 1-ethynyl-1-cyclohexanol as an optional component were added, and the mixture was stirred until it became uniform. Then, platinum was added as the component (C). A complex of siloxane and vinylsiloxane was added so as to be 100 ppm in terms of platinum with respect to the sum of (A) and (B) to prepare a silicone composition having a viscosity of 205 mPa · s.
[0038]
Then, the obtained silicone composition was applied at 0.6~0.7g / ^{m 2} polyethylene laminated paper (basis weight 100 g / ^{m 2),} as curing test, time to cure at 120 ° C. ( Seconds). Further, as a sample for the peeling force and the residual adhesion rate, a heat treatment was performed at 140 ° C. for 30 seconds to form a cured film. Table 1 shows the measurement results.
[0039]
Example 2 Synthesis of Organopolysiloxane-B 0.3 mol of hexamethyldisiloxane, 0.7 mol of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane, 28.75 mol of octamethylcyclotetrasiloxane The synthesis reaction was performed in the same manner as in Example 1 except that 0.075 mol of 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane was used to obtain the above formula (4) The average of the sum of X + Y is 1.4, the average of m is 0.3, n = 115 and the viscosity is 216 mPa. Thus, organopolysiloxane-B was obtained.
[0040]
Next, as the component (A), 100 parts of the polydimethylsiloxane-B obtained above, and as the component (B), methylhydrogenpolysiloxane 2 having both ends of a molecular chain blocked with a trimethylsiloxy group and having a viscosity of 20 mPa · s. 0.22 parts (SiH / SiCH = CH ₂ = 1.8), and 0.3 part of 1-ethynyl-1-cyclohexanol as an optional component were added, and the mixture was stirred until it became uniform. A complex of platinum and vinylsiloxane was added so as to be 100 ppm in terms of platinum with respect to the sum of (A) and (B) to prepare a silicone composition having a viscosity of 200 mPa · s. The same physical property test was performed. The results are also shown in Table 1.
[0041]
Example 3 Synthesis of Organopolysiloxane-C 0.1 mol of hexamethyldisiloxane, 0.9 mol of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane, 37.5 mol of octamethylcyclotetrasiloxane , 1,3,5,7-Tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane The synthesis reaction was carried out in the same manner as in Example 1 except that 0.0125 mol was used to obtain the above formula (4) , An organopolysiloxane-C having an average of X + Y of 1.8, an average of m of 0.05, n = 150 and a viscosity of 410 mPa · s was obtained.
[0042]
Next, as the component (A), 100 parts of the polydimethylsiloxane-C obtained above, and as the component (B), both ends of the molecular chain were blocked with a trimethylsiloxy group to have a viscosity of 20 mPa.s. 2.0 parts of methyl hydrogen polysiloxane (SiH / SiCH = CH ₂ = 1.8) and 0.3 part of 1-ethynyl-1-cyclohexanol as an optional component are added until uniform. After stirring, a complex of platinum and vinyl siloxane is added as a component (C) so as to be 100 ppm in terms of platinum with respect to the total of the above (A) and (B), and a silicone composition having a viscosity of 380 mPa · s The product was prepared and subjected to the same physical property tests as in Example 1. The results are also shown in Table 1.
[0043]
[Comparative Example 1]
(A) 100 parts of polydimethylsiloxane-D having a viscosity of 210 mPa · s in which both ends of a molecular chain are blocked with a dimethylvinylsiloxy group as a component, and (B) a viscosity in which both ends of a molecular chain are blocked with a trimethylsiloxy group. 2.9 parts (SiH / SiCH = CH ₂ = 1.8) of methylhydrogenpolysiloxane having a pressure of 20 mPa · s, and 0.3 part of 1-ethynyl-1-cyclohexanol as an optional component were added. Then, a complex of platinum and vinylsiloxane was added as a component (C) so as to be 100 ppm in terms of platinum with respect to the total of the above (A) and (B), and the viscosity was 195 mPa · s. A certain silicone composition was prepared and subjected to the same physical property tests as in Example 1. The results are also shown in Table 1.
[0044]
Comparative Example 2 Synthesis of Organopolysiloxane-E Same as Example 1 except that 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane was not used. The synthesis reaction was carried out to obtain an organopolysiloxane-E having an average of X + Y of 1.6, an average of m of 0, n = 115 and a viscosity of 210 mPa · s in the above formula (4).
[0045]
Next, as the component (A), 100 parts of the polydimethylsiloxane-E obtained above, and as the component (B), methylhydrogenpolysiloxane 2 having both ends of a molecular chain blocked with a trimethylsiloxy group and having a viscosity of 20 mPa · s. .14 parts (SiH / SiCH = CH ₂ = 1.8) and 0.3 part of 1-ethynyl-1-cyclohexanol as an optional component were added, and the mixture was stirred until it became uniform. A complex of platinum and vinylsiloxane was added so as to be 100 ppm in terms of platinum with respect to the sum of (A) and (B) to prepare a silicone composition having a viscosity of 200 mPa · s. The same physical property test was performed. The results are also shown in Table 1.
[0046]
[Comparative Example 3]
(A) 85 parts of polydimethylsiloxane-F having a viscosity of 210 mPa · s in which both ends of a molecular chain are blocked with dimethylvinylsiloxy groups and 200 mPa · s in which both ends of a molecular chain are blocked with trimethylsiloxy groups as a component. 15 parts of a certain polydimethylsiloxane-G, 2.1 parts of methyl hydrogen polysiloxane (SiH / SiCH = CH ₂ = 1) having a viscosity of 20 mPa · s in which both ends of a molecular chain are blocked with a trimethylsiloxy group as a component (B) .8), 0.3 part of 1-ethynyl-1-cyclohexanol was further added as an optional component, and the mixture was stirred until it became uniform. And a silicone group having a viscosity of 193 mPa · s, which is added to the total of (B) and 100 ppm in terms of platinum. Things were prepared and subjected to the same physical property tests of Example 1. The results are also shown in Table 2.
[0047]
Table 1 Structure of component (A) siloxane

[Table 2]

Claims (3)

(A) The following average composition formula (1)

A diorganopolysiloxane having an alkenyl group bonded to a silicon atom has the following structural formula

(Where R ¹ is an alkenyl group, R is a same or different monovalent hydrocarbon group containing no aliphatic unsaturated bond, X and Y are each 0 or 1, and the sum of X + Y is 1. 3 to 1.8, m is an integer of 0 or 1 to 3, and on average 0.02 to 0.5; the sum of X + Y + m is 1.6 to 1.9 on average; The curable silicone release agent composition according to claim 1, wherein the viscosity at 25 ° C synthesized by an alkali equilibration reaction represented by (n ≦ 250) is 50 to 1000 mmPa · s. A release paper on which a cured film of the composition according to claim 1 is formed.