JP3661743B2 - Method for producing epoxy group-containing organopolysiloxane and ultraviolet curable composition - Google Patents

Description

（式中、Ｒ¹は互いに同一又は異種の非置換又は置換の炭素数１〜１０の１価炭化水素基を示し、ａは０〜３の整数、ｐ，ｒは２以上の整数、ｑ，ｓは０以上の整数である。）
【００１１】
以下、本発明につき更に詳しく説明する。
本発明の第１発明は、Ｒ₃ＳｉＯ_1/2単位、ＳｉＯ_4/2単位及び（ＨＯ）ＳｉＯ_3/2単位（但し、Ｒは非置換又は置換の炭素数１〜１０の１価炭化水素基）を主構成単位とするＯＨ基含有オルガノポリシロキサンの該ＯＨ基に対し、上記一般式（１）又は（２）で示されるオルガノヒドロポリシロキサンのＳｉＨ基の過剰量を用いて、脱水素縮合反応させた後、得られた反応生成物中に残存するＳｉＨ基と、エポキシ基及びアルケニル基を含有する化合物の該アルケニル基とを付加反応させることを特徴とするエポキシ基含有オルガノポリシロキサンの製造方法である。
【００１２】
ここで、Ｒ₃ＳｉＯ_1/2単位、ＳｉＯ_4/2単位、（ＨＯ）ＳｉＯ_3/2単位を主構成単位とするＯＨ基をもつオルガノポリシロキサンにおいて、Ｒはメチル基、エチル基、プロピル基、ブチル基などのアルキル基、シクロヘキシル基などのシクロアルキル基、フェニル基、トリル基などのアリール基、又はこれらの基の炭素原子に結合している水素原子の一部又は全部をヒドロキシ基、シアノ基、ハロゲン原子などで置換したヒドロキシプロピル基、シアノエチル基、１−クロロプロピル基、３，３，３−トリフルオロプロピル基などから選択される非置換又は置換の炭素数１〜１０の１価炭化水素基であり、特に本発明のエポキシ基含有オルガノポリシロキサンの硬化物の剥離性の点で、アルキル基、アリール基であることが望ましい。
【００１３】
また、Ｒ₃ＳｉＯ_1/2単位／（ＳｉＯ_4/2単位＋（ＨＯ）ＳｉＯ_3/2単位）の比は０．５〜２、好ましくは０．６〜１．３である。モル比が０．５未満のものは粘度がばらつく等の理由により安定に製造することが困難であり、２を超えるものではエポキシ基含有オルガノポリシロキサンが十分な重剥離性を持たないおそれがある。またＯＨ基含有量は０．１〜５重量％、特に０．１〜３重量％であることが好ましい。０．１重量％未満では脱水素縮合反応の反応性が劣り、５重量％を超えるとエポキシ基含有オルガノポリシロキサンの硬化性が低下し、剥離性に悪影響を及ぼすおそれがある。
【００１４】
なお、上記オルガノポリシロキサンは、その１種を単独で又は２種以上を併用して用いることができる。
【００１５】
次に、オルガノヒドロポリシロキサンとしては、下記一般式（１）又は（２）で示されるものを使用する。
【００１６】
【化３】

（式中、Ｒ¹は互いに同一又は異種の非置換又は置換の炭素数１〜１０の１価炭化水素基を示し、ａは０〜３の整数、ｐ，ｒは２以上の整数、ｑ，ｓは０以上の整数である。）
【００１７】
ここで、Ｒ¹としては、前記Ｒで例示したと同様のものを挙げることができる。また、ｐ，ｑ及びｒ，ｓは、このオルガノヒドロポリシロキサンの２５℃における粘度を１〜５０，０００ｃＰ、特に５〜１０，０００ｃＰとする数であり、更に、全シロキサン単位のうち、ＨＲ¹ＳｉＯ単位が２〜１００モル％、特に２〜７０モル％であることが好ましい。
【００１８】
上記式（１），（２）の化合物としては、下記のものを例示することができる。なお、下記式において、Ｍｅはメチル基、Ｐｈはフェニル基を示す。
【００１９】
【化４】

【００２０】
なお、上記オルガノヒドロポリシロキサンとしては、その１種を単独で又は２種以上を組み合わせて用いることができる。
【００２１】
本発明のエポキシ基含有オルガノポリシロキサンの製造には、まず、Ｒ₃ＳｉＯ_1/2単位、ＳｉＯ_4/2単位、（ＨＯ）ＳｉＯ_3/2単位を主構成単位とするＯＨ基をもつオルガノポリシロキサンと式（１）又は（２）のオルガノヒドロポリシロキサンの脱水素縮合反応を行う。
【００２２】
このとき、ＯＨ基をもつオルガノポリシロキサンとオルガノヒドロポリシロキサンの使用割合は、ＯＨ基をもつオルガノポリシロキサン／オルガノヒドロポリシロキサンの重量比が１／９９〜９５／５、特に２／９８〜７０／３０が好ましい。ＯＨ基をもつオルガノポリシロキサンの割合が１／９９より少ないと、重剥離性が不十分となり、９５／５より多いと、硬化性、残留接着性が低下するおそれがある。
【００２３】
また、ＳｉＨ基／ＯＨ基のモル比が２以上、特に４以上となるように使用することが好ましい。
【００２４】
脱水素縮合反応に際し、脱水素縮合触媒を用いる。この触媒としては、塩化白金酸、塩化白金酸のアルコール溶液、塩化白金酸とアルコールとの反応物、塩化白金酸とオレフィン化合物との反応物、塩化白金酸とビニル基含有シロキサンとの反応物などの白金系触媒がある。これらの触媒添加量には特に制限はないが、ＯＨ基をもつオルガノポリシロキサンとオルガノヒドロポリシロキサンの合計重量の０．０１〜５％でよい。
【００２５】
この反応は、通常、室温〜３００℃で行えばよいが、４０℃以上に加熱した方が反応が早く進行する。反応時間は特に限定されないが、０．１〜１０時間が好ましい。反応は、必要に応じて溶剤中で行う。溶剤としては、トルエン、キシレンなどの芳香族系溶剤、ヘキサン、オクタンなどの脂肪族系溶剤、メチルエチルケトン、メチルイソブチルケトンなどのケトン系溶剤、酢酸エチル、酢酸イソブチルなどのエステル系溶剤、又はこれらの混合溶剤を使用することができる。また、反応の雰囲気としては、空気中、不活性気体中のいずれでもよい。
【００２６】
脱水素縮合反応終了後、反応混合物からＯＨ基をもつオルガノポリシロキサンとオルガノヒドロポリシロキサンの脱水素縮合反応物を単離、精製してもよい。これには、反応混合物を活性炭処理などにより脱水素縮合触媒を除去し、溶剤を使用した場合は、加熱及び／又は減圧下で留去するなどの方法を採用し得る。
【００２７】
本発明においては、上記脱水素縮合反応終了後、脱水素縮合反応の反応混合物にエポキシ基及びアルケニル基含有化合物を添加して、又はエポキシ基及びアルケニル基含有化合物に脱水素縮合反応の反応混合物を添加して、反応混合物中に残存するＳｉＨ基とアルケニル基の付加反応を行う。
【００２８】
ここで、この反応に用いるエポキシ基及びアルケニル基含有化合物は、１分子中にエポキシ基及びアルケニル基をそれぞれ少なくとも１個以上もつ有機化合物であり、具体的には、４−ビニルシクロヘキセンオキシド、４−イソプロペニル−１−メチルシクロヘキセンオキシド、アリルグリシジルエーテル、１，５−ヘキサジエンモノオキシド、グリシジル（メタ）アクリレートなどが挙げられる。
【００２９】
本発明において、ＯＨ基をもつオルガノポリシロキサンとオルガノヒドロポリシロキサンとの脱水素縮合反応物と、エポキシ基及びアルケニル基含有化合物の使用割合は、アルケニル基の数がＳｉＨ基の数よりも多くなるようにすることが好ましく、アルケニル基／ＳｉＨ基のモル比が１．０以上、特に１．０５〜１．５が好ましい。
【００３０】
付加反応に際し、触媒量の付加反応触媒を用いるが、脱水素縮合触媒としての白金系触媒が存在する場合は、新たに付加反応触媒を添加しなくてもよく、脱水素縮合反応を行った反応容器にエポキシ基及びアルケニル基含有化合物を添加して次の付加反応を行うことができるので好都合である。付加反応触媒としては、前記の白金系触媒が例示できる。この反応は、通常、室温〜３００℃で行えばよいが、４０℃以上に加熱した方が反応が早く進行する。反応時間は特に限定されない。反応は、必要に応じて前記した溶剤中で行う。また、反応の雰囲気としては、空気中、不活性気体中のいずれでもよい。
【００３１】
付加反応終了後、必要に応じて反応混合物を水洗や活性炭処理などにより付加反応触媒を除去し、溶剤を使用した場合は、加熱及び／又は減圧下で留去して、エポキシ基含有オルガノポリシロキサンを得る。
【００３２】
本発明で得られるエポキシ基含有オルガノポリシロキサンの全ケイ素原子中のエポキシ基含有有機基が結合したケイ素原子の割合は２〜４０モル％がよい。２モル％未満では硬化性、残留接着率が低下するおそれがある。４０モル％を超えると、必要以上に重剥離となり、粘着物質からの剥離が不可能となる場合がある。特には５〜２５モル％が好ましい。
【００３３】
次に、本発明の第２発明は、上記の方法で製造されたエポキシ基含有オルガノポリシロキサンとオニウム塩光開始剤とを含有してなる紫外線硬化性組成物である。
【００３４】
即ち、本発明の上記製造方法によって得られたエポキシ基含有有機基をもつオルガノポリシロキサンは、それ単独で又はこれとは重合度やエポキシ基含有率などの異なるオルガノポリシロキサンと混合し、更に光開始剤を添加して、紫外線硬化性オルガノポリシロキサン組成物とすることができる。この組成物は各成分の所定量を均一に混合することによって得られる。必要に応じて、エポキシ系希釈剤、ビニルエーテル系希釈剤、基材への密着向上剤、レベリング剤、帯電防止剤、消泡剤、顔料、他種のオルガノポリシロキサンなどを添加してもよいし、有機溶剤で希釈して使用してもよい。
【００３５】
また、剥離力を調節することを目的に他種のエポキシ基含有オルガノポリシロキサンを併用してもよい。
【００３６】
ここで、上記光開始剤としては、オニウム塩系光開始剤が使用され、例えば、
Ｒ² ₂Ｉ⁺Ｘ^-，Ｒ² ₃Ｓ⁺Ｘ^-，Ｒ² ₃Ｓｅ⁺Ｘ^-，Ｒ² ₄Ｐ⁺Ｘ^-，Ｒ²Ｎ⁺Ｘ^-
（Ｒ²はアリール基，Ｘ^-はＳｂＦ₆ ^-，ＡｓＦ₆ ^-，ＰＦ₆ ^-，ＢＦ₄ ^-，ＨＳＯ₄ ^-，ＣｌＯ₄ ^-などの陰イオン）
で示されるジアリールヨードニウム塩、トリアリールスルホニウム塩、トリアリールセレノニウム塩、テトラアリールホスホニウム塩、アリールジアゾニウム塩などが挙げられる。硬化反応性の点で、ジアリールヨードニウム、トリアリールスルホニウムの六フッ化アンチモン酸塩が好ましい。オニウム塩の添加量は、上記エポキシ基含有オルガノポリシロキサン１００重量部に対して０．１〜２０重量部とすればよい。これより少ないと硬化性が不十分であり、多いと硬化皮膜の表面状態に悪影響が生じて、剥離特性が劣化するおそれがある。
【００３７】
本発明の組成物は、短時間の紫外線照射によって容易に硬化することから、剥離紙・剥離フィルム用剥離剤、粘着テープの背面処理剤、金属，プラスチックの保護コーティング剤として使用できる。
【００３８】
本発明の組成物が塗工される基材としては、グラシン紙，クラフト紙，クレーコート紙などの紙基材、ポリエチレンラミネート上質紙，ポリエチレンラミネートクラフト紙などのラミネート紙、ポリエステル，ポリプロピレン，ポリエチレン，ポリ塩化ビニル，ポリテトラフルオロエチレン，ポリイミドなどの合成樹脂から得られるプラスチックフィルムやシート、アルミニウムなどの金属箔等が挙げられる。
【００３９】
基材に本発明の組成物を塗布するには、ロール塗布、グラビア塗布、ワイヤードクター塗布、エアーナイフ塗布、ディッピング塗布などの公知の方法を用いることができる。塗布量としては０．０１〜１００ｇ／ｍ²とすればよく、この塗膜は紫外線を照射すれば容易に硬化する。紫外線の光源としては、高圧水銀ランプ、中圧水銀ランプ、低圧水銀ランプ、メタルハライドランプ、水銀アーク灯などが例示できる。上記塗膜を硬化させるためには高圧水銀ランプ（８０Ｗ／ｃｍ）を使用した場合には５〜２０ｃｍの距離から０．０１〜１０秒照射すればよい。
【００４０】
【発明の効果】
本発明によれば、エポキシ基含有オルガノポリシロキサンを取り扱い性よく、ゲル化を生じることなく工業的に有利に製造でき、またこのエポキシ基含有オルガノポリシロキサンを主成分とする硬化性組成物の硬化皮膜は、粘着物質に対する重剥離性に優れ、粘着剤層の粘着力を低下させず、シリコーン移行が少ないものである。
【００４１】
【実施例】
以下、実施例と比較例を示し、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、下記例において、部は重量部を示す。また、下記の例で、剥離力、残留接着率、シリコーン移行性は下記方法で評価した。
【００４２】
剥離力
シリコーン組成物を、ポリエチレンラミネート上質紙表面に固形分で０．８ｇ／ｍ²となるようにオフセット転写機を用いて塗布し、８０Ｗ／ｃｍの高圧水銀灯を８ｃｍの距離から照射して、硬化皮膜を形成させた。室温で１日放置後、この硬化皮膜表面に、ポリエステル粘着テープＮｏ．３１Ｂ（日東電工（株）製，２５ｍｍ幅）又は粘着テープＴｅｓａ７４７５（ＢＤＦ社製，２５ｍｍ幅）を貼付し、試料を作成した。２０℃で１日又は５０℃で６日放置してエージングさせた後、試料のテープを引張試験機を用いて、１８０°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（ｇ／２５ｍｍ）を測定した。
【００４３】
残留接着率
剥離力測定の場合と同様にして、基材表面にシリコーン組成物の硬化皮膜を形成させた。室温で１日放置後、この硬化皮膜表面にポリエステル粘着テープＮｏ．３１Ｂ（日東電工（株）製）を貼り合わせ、２０ｇ／ｃｍ²の荷重下、７０℃で２０時間エージングさせた。このエージング後のテープを剥がし、ポリエステルフィルムに貼り付けた。このテープをポリエステルフィルムから１８０°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（ｇ／２５ｍｍ）を測定した。一方、シリコーン硬化皮膜に貼り合わせない未処理テープをポリエステルフィルムから剥離するのに要する力（ｇ／２５ｍｍ）を測定し、これらの比をとって百分率で表した。
【００４４】
シリコーン移行性
剥離力の場合と同様にして、基材表面にシリコーン組成物の硬化皮膜を形成させた。その表面にポリエステルフィルムを重ね、１０ｋｇ／ｃｍ²の荷重で１日放置した。硬化皮膜に接触していたポリエステルフィルムの表面のケイ素の存在量を蛍光Ｘ線分析装置で測定し、ブランクのポリエステルフィルムのケイ素の存在量との比を求めた。
【００４５】
〔実施例１〕
撹拌装置、温度計、還流冷却器、滴下ロートを取り付けた４つ口フラスコに、トルエン（３３部）、Ｍｅ₃ＳｉＯ_1/2単位、ＳｉＯ_4/2単位、（ＨＯ）ＳｉＯ_3/2単位からなるＯＨ基をもつオルガノポリシロキサンの６０％トルエン溶液（Ｍ／Ｑ＝０．７０，ＯＨ基含有量０．７７重量％）（６４部）、及び平均組成式が次式で表されるオルガノヒドロポリシロキサン（２１８部）を仕込んだ。
Ｍｅ₃ＳｉＯ−（ＨＭｅＳｉＯ）₄−（Ｍｅ₂ＳｉＯ）₂₄−ＳｉＭｅ₃
【００４６】
ここに、白金触媒の０．５％トルエン溶液（０．１６部）を添加し、１３２℃で３時間還流させ、脱水素縮合反応を行った後、３０℃まで放冷した。
【００４７】
一方、別の撹拌装置、温度計、還流冷却器、滴下ロートを取り付けた４つ口フラスコに、４−ビニルシクロヘキセンオキシド（６０部）、トルエン（１４９部）、白金触媒の０．５％トルエン溶液（０．０８部）を仕込み、７０℃に加熱した。ここに、脱水素縮合反応物の全量を２時間かけて滴下した。滴下終了後、７０℃で１時間撹拌した。８０℃，３Ｔｏｒｒで、トルエン、揮発成分を留去して、サンプル１（２７９部）を得た。これは褐色透明の液体で、粘度１３２ｃＰ，エポキシ当量８６０であった。サンプル１のＭｅ₃ＳｉＯ_1/2単位、ＳｉＯ_4/2単位、（ＨＯ）ＳｉＯ_3/2単位からなるＯＨ基をもつオルガノポリシロキサンに由来する部分の重量比（レジン量）は１３％である。
【００４８】
〔実施例２〕
ＯＨ基をもつオルガノポリシロキサンの６０％トルエン溶液（Ｍ／Ｑ＝０．７０，ＯＨ基含有量０．７７重量％）の使用量を１４７部、脱水素縮合反応時のトルエン使用量を１２部にした以外は実施例１と同様の操作を行い、サンプル２（３３９部）を得た。これは褐色透明の液体で、粘度３０８ｃＰ，エポキシ当量８０３であった。サンプル２のレジン量は２５％である。
【００４９】
〔実施例３〕
ＯＨ基をもつオルガノポリシロキサンの６０％トルエン溶液（Ｍ／Ｑ＝０．７０，ＯＨ基含有量０．７７重量％）の使用量を４４２部、脱水素縮合反応時のトルエン使用量を０部にした以外は実施例１と同様の操作を行い、サンプル３（５２１部）を得た。これは褐色透明の液体で、粘度１１，６００ｃＰ，エポキシ当量１，５５０であった。サンプル３のレジン量は５０％である。
【００５０】
〔実施例４〕
実施例１で得られたサンプル１（１００部）、ヨードニウム塩光開始剤（１部）を混合し、処理液（シリコーン組成物）を調製した。この処理液の硬化皮膜の剥離力、残留接着率、シリコーン移行性を上記の評価方法で測定した。結果を表１に示す。
【００５１】
〔実施例５〕
実施例２で得られたサンプル２（１００部）、ヨードニウム塩光開始剤（１部）を混合し、処理液を調製した。この処理液の硬化皮膜の剥離力、残留接着率、シリコーン移行性を上記の評価方法で測定した。結果を表１に示す。
【００５２】
〔実施例６〕
実施例３で得られたサンプル３（１００部）、ヨードニウム塩光開始剤（１部）を混合し、処理液を調製した。この処理液の硬化皮膜の剥離力、残留接着率、シリコーン移行性を上記の評価方法で測定した。結果を表１に示す。
【００５３】
〔比較例１〕
ＯＨ基をもつオルガノポリシロキサンの６０％トルエン溶液（Ｍ／Ｑ＝０．７０，ＯＨ基含有量０．７７重量％）を４２部、平均組成式
Ｍｅ₃ＳｉＯ−（ＥＭｅＳｉＯ）₄−（Ｍｅ₂ＳｉＯ）₂₄−ＳｉＭｅ₃
（Ｅはβ−（３，４−エポキシシクロヘキシル）エチル基）
で示されるエポキシ基を有するオルガノポリシロキサン７５部を混合し、８０℃，３Ｔｏｒｒで、トルエン、揮発成分を留去して、サンプル４（９８部）を得た。このサンプル４のレジン量は２５％である。サンプル４（１００部）、ヨードニウム塩光開始剤（１部）を混合し、処理液を調製した。この処理液の硬化皮膜の剥離力、残留接着率、シリコーン移行性を上記の評価方法で測定した。結果を表１に示す。
【００５４】
〔比較例２〕
Ｍｅ₃ＳｉＯ−（ＥＭｅＳｉＯ）₄−（Ｍｅ₂ＳｉＯ）₂₄−ＳｉＭｅ₃
（Ｅはβ−（３，４−エポキシシクロヘキシル）エチル基）
で示されるエポキシ基を有するオルガノポリシロキサン（１００部）とヨードニウム塩光開始剤（１部）を混合し、処理液を調製した。この処理液の硬化皮膜の剥離力、残留接着率、シリコーン移行性を上記の評価方法で測定した。結果を表１に示す。
【００５５】
【表１】

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing an epoxy group-containing organopolysiloxane that is suitably used as a main component of an ultraviolet curable composition for release paper, and an ultraviolet curable composition using the epoxy group-containing organopolysiloxane.
[0002]
[Prior art and problems to be solved by the invention]
Conventionally, heat, ultraviolet or electron beam curable silicone compositions have been applied to the substrate surface for the purpose of preventing adhesion and adhesion between the substrate such as paper, processed paper, and plastic film and the pressure-sensitive adhesive substance. A cured film is formed, and this is generally called a release paper.
[0003]
A composition for forming a peelable cured film is required to be cured at a low temperature and in a short time in order to improve productivity and save energy and to be applied to a substrate having poor heat resistance. In particular, in order to prevent deformation of the substrate due to heat, it is advantageous to form a curable film on the substrate by irradiating with ultraviolet rays.
[0004]
As a useful method for producing a composition for forming a peelable cured film, there is a method in which a composition comprising an organopolysiloxane having an epoxy group-containing organic group and an onium salt photoinitiator is cured by irradiation with ultraviolet rays (Japanese Patent Application Laid-Open (JP-A)). Sho 56-38350). In this case, the peelability of the cured film with respect to the adhesive substance depends on the epoxy group content of the organopolysiloxane having an epoxy group-containing organic group, and the greater the epoxy group content, the heavier the peel strength of the cured film becomes. .
[0005]
In this case, it is important that the pressure-sensitive adhesive material is not easily peeled off. In such applications, the peelable silicone composition is made to have a highly peelable film property and is usually not easily peeled off, and when necessary, a strong force is applied for peeling.
[0006]
JP-A-7-2976 discloses a peeling force adjusting (heavy peeling) additive for an ultraviolet curable epoxy silicone release agent and a peeling force adjusting composition using the same. In order to produce an epoxy functional silicone containing a Q unit, which is a heavy release component in this composition, an epoxy functional M unit, and at least one of a D unit or a T unit, the Q unit, M ^It is necessary to synthesize in advance a SiH functional resin containing at least one of ^H unit and D unit or T unit. Dimethylchlorosilane is used as the raw material, but this compound has a drawback that it is difficult to handle because of its low boiling point, high volatility, and strong hydrolyzability.
[0007]
JP-A-6-166740 also discloses a peeling force adjusting (heavy peeling) additive for an ultraviolet curable epoxy silicone release agent and a peeling force adjusting composition using the same. The heavy release component in this composition is an addition reaction between a low molecular weight SiH-containing silicone fluid and a silicone resin such as M ^Vi MQ or M ^Vi MTQ or an allylated polyether, and further, excess SiH groups are converted to unsaturated epoxy. It has been shown to be obtained by reacting with a containing compound. In this case, it is difficult to control the reaction because the addition reaction between the SiH-containing silicone fluid and the silicone resin such as M ^Vi MQ or M ^Vi MTQ is too fast, and gelation may occur during the reaction. When an allylated polyether is used, there is a problem that the cation reactivity of the final composition is inhibited.
[0008]
The present invention was made in view of the above circumstances, and an epoxy group-containing organopolysiloxane that is effective as a main component of an ultraviolet curable composition that gives a cured product with good residual adhesion and low silicone migration due to heavy peeling is described above. It is an object of the present invention to provide a method for producing an industrially advantageous method by eliminating the disadvantages of the prior art, and an ultraviolet curable composition using the epoxy group-containing organopolysiloxane.
[0009]
Means for Solving the Problem and Embodiment of the Invention
As a result of intensive studies to achieve the above object, the present inventor has found that R ₃ SiO _1/2 unit, SiO _4/2 unit, and (HO) SiO _3/2 unit (where R is unsubstituted or substituted). SiH of an organohydropolysiloxane represented by the following general formula (1) or (2) with respect to the OH group of the OH group-containing organopolysiloxane having a monovalent hydrocarbon group having 1 to 10 carbon atoms as a main structural unit By carrying out an addition reaction between the SiH group remaining in the obtained reaction product and the alkenyl group of the compound containing an epoxy group and an alkenyl group after dehydrogenative condensation using an excess of the group The epoxy group-containing organopolysiloxane can be obtained efficiently and surely with ease of handling, no gelation, and the epoxy group-containing organopolysiloxane as the main material. UV curable composition containing a photoinitiator, those residual adhesion rate peelable well, that was found that providing silicone migration, less cured product, the present invention has been accomplished.
[0010]
[Chemical formula 2]

(In the formula, R ¹ represents the same or different unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, a is an integer of 0 to 3, p and r are integers of 2 or more, q, s is an integer of 0 or more.)
[0011]
Hereinafter, the present invention will be described in more detail.
The first invention of the present invention is an R ₃ SiO _1/2 unit, a SiO _4/2 unit and a (HO) SiO _3/2 unit (where R is an unsubstituted or substituted monovalent hydrocarbon having 1 to 10 carbon atoms) Dehydrogenation using an excessive amount of SiH group of the organohydropolysiloxane represented by the above general formula (1) or (2) with respect to the OH group of the OH group-containing organopolysiloxane having a main group as a main structural unit. An epoxy group-containing organopolysiloxane characterized by subjecting an SiH group remaining in a reaction product obtained after the condensation reaction to an addition reaction of the alkenyl group of a compound containing an epoxy group and an alkenyl group. It is a manufacturing method.
[0012]
Here, in the organopolysiloxane having an OH group having R ₃ SiO _1/2 unit, SiO _4/2 unit, and (HO) SiO _3/2 unit as main constituent units, R is a methyl group, an ethyl group, a propyl group. An alkyl group such as a butyl group, a cycloalkyl group such as a cyclohexyl group, an aryl group such as a phenyl group and a tolyl group, or a part or all of the hydrogen atoms bonded to the carbon atoms of these groups is a hydroxy group, An unsubstituted or substituted monovalent carbon atom having 1 to 10 carbon atoms selected from a hydroxypropyl group, a cyanoethyl group, a 1-chloropropyl group, a 3,3,3-trifluoropropyl group substituted with a group, a halogen atom, etc. It is a hydrogen group, and in particular, an alkyl group and an aryl group are desirable from the viewpoint of peelability of the cured product of the epoxy group-containing organopolysiloxane of the present invention.
[0013]
The ratio of R ₃ SiO _1/2 unit / (SiO _4/2 unit + (HO) SiO _3/2 unit) is 0.5 to 2, preferably 0.6 to 1.3. When the molar ratio is less than 0.5, it is difficult to produce stably due to reasons such as variation in viscosity. When the molar ratio exceeds 2, the epoxy group-containing organopolysiloxane may not have sufficient heavy peelability. . The OH group content is preferably 0.1 to 5% by weight, particularly preferably 0.1 to 3% by weight. If it is less than 0.1% by weight, the reactivity of the dehydrogenative condensation reaction is inferior. If it exceeds 5% by weight, the curability of the epoxy group-containing organopolysiloxane is lowered, and the peelability may be adversely affected.
[0014]
In addition, the said organopolysiloxane can be used individually by 1 type or in combination of 2 or more types.
[0015]
Next, as the organohydropolysiloxane, one represented by the following general formula (1) or (2) is used.
[0016]
[Chemical 3]

(In the formula, R ¹ represents the same or different unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, a is an integer of 0 to 3, p and r are integers of 2 or more, q, s is an integer of 0 or more.)
[0017]
Here, examples of R ¹ include the same as those exemplified for R. Moreover, p, q and r, s are numbers which make this organohydropolysiloxane have a viscosity at 25 ° C. of 1 to 50,000 cP, particularly 5 to 10,000 cP, and among all siloxane units, HR ¹ It is preferable that the SiO unit is 2 to 100 mol%, particularly 2 to 70 mol%.
[0018]
Examples of the compounds of the above formulas (1) and (2) include the following. In the following formulae, Me represents a methyl group, and Ph represents a phenyl group.
[0019]
[Formula 4]

[0020]
In addition, as said organohydropolysiloxane, the 1 type can be used individually or in combination of 2 or more types.
[0021]
In the production of the epoxy group-containing organopolysiloxane of the present invention, first, an organopolysiloxane having an OH group having R ₃ SiO _1/2 units, SiO _4/2 units, and (HO) SiO _3/2 units as main constituent units. A dehydrogenative condensation reaction between the siloxane and the organohydropolysiloxane of the formula (1) or (2) is performed.
[0022]
At this time, the use ratio of the organopolysiloxane having OH group and the organohydropolysiloxane is such that the weight ratio of the organopolysiloxane having OH group / organohydropolysiloxane is 1/99 to 95/5, particularly 2/98 to 70. / 30 is preferred. When the ratio of the organopolysiloxane having an OH group is less than 1/99, the heavy peelability is insufficient, and when it is more than 95/5, the curability and the residual adhesiveness may be lowered.
[0023]
Moreover, it is preferable to use it so that the molar ratio of SiH group / OH group is 2 or more, particularly 4 or more.
[0024]
A dehydrogenation condensation catalyst is used in the dehydrogenation condensation reaction. Examples of the catalyst include chloroplatinic acid, an alcohol solution of chloroplatinic acid, a reaction product of chloroplatinic acid and alcohol, a reaction product of chloroplatinic acid and an olefin compound, a reaction product of chloroplatinic acid and a vinyl group-containing siloxane, and the like. There are platinum-based catalysts. The amount of the catalyst added is not particularly limited, but may be 0.01 to 5% of the total weight of the organopolysiloxane having an OH group and the organohydropolysiloxane.
[0025]
This reaction may usually be performed at room temperature to 300 ° C, but the reaction proceeds faster when heated to 40 ° C or higher. Although reaction time is not specifically limited, 0.1 to 10 hours are preferable. The reaction is carried out in a solvent as necessary. Solvents include aromatic solvents such as toluene and xylene, aliphatic solvents such as hexane and octane, ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, ester solvents such as ethyl acetate and isobutyl acetate, or a mixture thereof. Solvents can be used. The reaction atmosphere may be either air or inert gas.
[0026]
After completion of the dehydrogenation condensation reaction, a dehydrogenation condensation product of an organopolysiloxane having an OH group and an organohydropolysiloxane may be isolated and purified from the reaction mixture. For this, a method of removing the dehydrogenative condensation catalyst from the reaction mixture by treatment with activated carbon or the like, and when using a solvent, a method of distilling off under heating and / or reduced pressure can be employed.
[0027]
In the present invention, after completion of the dehydrogenation condensation reaction, an epoxy group and alkenyl group-containing compound is added to the reaction mixture of the dehydrogenation condensation reaction, or a reaction mixture of the dehydrogenation condensation reaction is added to the epoxy group and alkenyl group-containing compound. And the addition reaction of the SiH groups and alkenyl groups remaining in the reaction mixture is carried out.
[0028]
Here, the epoxy group and alkenyl group-containing compound used in this reaction is an organic compound having at least one epoxy group and alkenyl group in one molecule, specifically, 4-vinylcyclohexene oxide, 4- Examples include isopropenyl-1-methylcyclohexene oxide, allyl glycidyl ether, 1,5-hexadiene monooxide, and glycidyl (meth) acrylate.
[0029]
In the present invention, the dehydrogenative condensation reaction product of an organopolysiloxane having an OH group and an organohydropolysiloxane and the use ratio of the epoxy group and alkenyl group-containing compound is such that the number of alkenyl groups is larger than the number of SiH groups. The molar ratio of alkenyl group / SiH group is preferably 1.0 or more, particularly preferably 1.05 to 1.5.
[0030]
In the addition reaction, a catalytic amount of the addition reaction catalyst is used. However, when a platinum-based catalyst as a dehydrogenation condensation catalyst is present, it is not necessary to add a new addition reaction catalyst. Conveniently, the epoxy group- and alkenyl group-containing compound can be added to the container to carry out the following addition reaction. Examples of the addition reaction catalyst include the above platinum-based catalysts. This reaction may usually be performed at room temperature to 300 ° C, but the reaction proceeds faster when heated to 40 ° C or higher. The reaction time is not particularly limited. The reaction is carried out in the aforementioned solvent as necessary. The reaction atmosphere may be either air or inert gas.
[0031]
After completion of the addition reaction, if necessary, the reaction mixture is washed with water or activated carbon to remove the addition reaction catalyst. When a solvent is used, the reaction mixture is distilled off under heating and / or reduced pressure to produce an epoxy group-containing organopolysiloxane. Get.
[0032]
The ratio of silicon atoms to which epoxy group-containing organic groups are bonded in all silicon atoms of the epoxy group-containing organopolysiloxane obtained in the present invention is preferably 2 to 40 mol%. If it is less than 2 mol%, the curability and the residual adhesion rate may decrease. When it exceeds 40 mol%, it will be heavy peeling more than necessary, and peeling from an adhesive substance may become impossible. In particular, 5 to 25 mol% is preferable.
[0033]
Next, the second invention of the present invention is an ultraviolet curable composition comprising the epoxy group-containing organopolysiloxane produced by the above method and an onium salt photoinitiator.
[0034]
That is, the organopolysiloxane having an epoxy group-containing organic group obtained by the above-described production method of the present invention is mixed alone or with an organopolysiloxane having a different degree of polymerization or epoxy group content, An initiator can be added to obtain an ultraviolet curable organopolysiloxane composition. This composition is obtained by uniformly mixing a predetermined amount of each component. If necessary, an epoxy diluent, a vinyl ether diluent, an adhesion improver for a substrate, a leveling agent, an antistatic agent, an antifoaming agent, a pigment, and other types of organopolysiloxane may be added. Alternatively, it may be diluted with an organic solvent.
[0035]
Moreover, you may use together another kind of epoxy-group-containing organopolysiloxane for the purpose of adjusting peeling force.
[0036]
Here, as the photoinitiator, an onium salt photoinitiator is used, for example,
R ² ₂ I ⁺ X ⁻ , R ² ₃ S ⁺ X ⁻ , R ² ₃ Se ⁺ X ⁻ , R ² ₄ P ⁺ X ⁻ , R ² N ⁺ X ⁻
(R ² is an aryl group, X ⁻ is an anion such as SbF ₆ ⁻ , AsF ₆ ⁻ , PF ₆ ⁻ , BF ₄ ⁻ , HSO ₄ ⁻ , ClO ₄ ⁻ )
And diaryl iodonium salts, triaryl sulfonium salts, triaryl selenonium salts, tetraaryl phosphonium salts, aryl diazonium salts, and the like. From the viewpoint of curing reactivity, diaryl iodonium and triarylsulfonium hexafluoroantimonates are preferred. The addition amount of the onium salt may be 0.1 to 20 parts by weight with respect to 100 parts by weight of the epoxy group-containing organopolysiloxane. If it is less than this, the curability is insufficient, and if it is more, the surface condition of the cured film will be adversely affected, and the peeling characteristics may be deteriorated.
[0037]
Since the composition of the present invention is easily cured by ultraviolet irradiation for a short time, it can be used as a release agent for release paper / release film, a back treatment agent for adhesive tape, and a protective coating agent for metals and plastics.
[0038]
As the base material to which the composition of the present invention is applied, paper base materials such as glassine paper, kraft paper, clay coated paper, laminated paper such as polyethylene laminated fine paper, polyethylene laminated kraft paper, polyester, polypropylene, polyethylene, Examples thereof include plastic films and sheets obtained from synthetic resins such as polyvinyl chloride, polytetrafluoroethylene, and polyimide, and metal foils such as aluminum.
[0039]
In order to apply the composition of the present invention to the substrate, known methods such as roll coating, gravure coating, wire doctor coating, air knife coating and dipping coating can be used. The coating amount may be 0.01 to 100 g / m ² , and this coating film is easily cured when irradiated with ultraviolet rays. Examples of the ultraviolet light source include a high-pressure mercury lamp, a medium-pressure mercury lamp, a low-pressure mercury lamp, a metal halide lamp, and a mercury arc lamp. In order to cure the coating film, when a high-pressure mercury lamp (80 W / cm) is used, it may be irradiated for 0.01 to 10 seconds from a distance of 5 to 20 cm.
[0040]
【The invention's effect】
According to the present invention, an epoxy group-containing organopolysiloxane can be produced industrially advantageously without causing gelation with good handleability, and curing of a curable composition comprising the epoxy group-containing organopolysiloxane as a main component. The film is excellent in heavy peelability for the adhesive substance, does not decrease the adhesive strength of the adhesive layer, and has little silicone migration.
[0041]
【Example】
EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example. In addition, in the following example, a part shows a weight part. In the following examples, the peel strength, residual adhesion rate, and silicone migration were evaluated by the following methods.
[0042]
Peeling force The silicone composition was applied to the surface of a polyethylene laminate fine paper so that the solid content was 0.8 g / m ² using an offset transfer machine, and an 80 W / cm high-pressure mercury lamp was applied from a distance of 8 cm. Irradiated to form a cured film. After standing at room temperature for 1 day, the surface of the cured film was coated with polyester adhesive tape No. 31B (manufactured by Nitto Denko Corporation, 25 mm width) or adhesive tape Tesa 7475 (manufactured by BDF, 25 mm width) was attached to prepare a sample. After aging by leaving at 20 ° C. for 1 day or 50 ° C. for 6 days, the sample tape is peeled off at a 180 ° angle at a peeling speed of 0.3 m / min using a tensile tester. The force (g / 25 mm) was measured.
[0043]
Residual adhesion rate A cured film of the silicone composition was formed on the surface of the substrate in the same manner as in the measurement of the peel force. After standing at room temperature for 1 day, polyester adhesive tape No. 31B (manufactured by Nitto Denko Corporation) was bonded and aged at 70 ° C. for 20 hours under a load of 20 g / cm ² . The tape after aging was peeled off and attached to a polyester film. The tape was peeled off from the polyester film at an angle of 180 ° at a peeling speed of 0.3 m / min, and the force (g / 25 mm) required for peeling was measured. On the other hand, the force (g / 25 mm) required to peel off the untreated tape not bonded to the cured silicone film from the polyester film was measured, and these ratios were expressed as a percentage.
[0044]
Silicone transferability A cured film of the silicone composition was formed on the substrate surface in the same manner as in the case of the peeling force. A polyester film was overlaid on the surface and left for 1 day under a load of 10 kg / cm ² . The amount of silicon present on the surface of the polyester film that had been in contact with the cured film was measured with a fluorescent X-ray analyzer, and the ratio to the amount of silicon present in the blank polyester film was determined.
[0045]
[Example 1]
From a toluene (33 parts), Me ₃ SiO _1/2 unit, SiO _4/2 unit, (HO) SiO _3/2 unit to a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and dropping funnel 60% toluene solution of organopolysiloxane having OH groups (M / Q = 0.70, OH group content 0.77% by weight) (64 parts), and organohydro having an average composition formula represented by the following formula Polysiloxane (218 parts) was charged.
Me ₃ SiO— (HMeSiO) ₄ — (Me ₂ SiO) ₂₄ —SiMe ₃
[0046]
A 0.5% toluene solution (0.16 part) of a platinum catalyst was added thereto, and the mixture was refluxed at 132 ° C. for 3 hours to perform a dehydrogenative condensation reaction, and then allowed to cool to 30 ° C.
[0047]
On the other hand, in a four-necked flask equipped with another stirrer, thermometer, reflux condenser, and dropping funnel, 4-vinylcyclohexene oxide (60 parts), toluene (149 parts), 0.5% toluene solution of platinum catalyst (0.08 parts) was charged and heated to 70 ° C. Here, the entire amount of the dehydrogenative condensation reaction product was dropped over 2 hours. After completion of dropping, the mixture was stirred at 70 ° C. for 1 hour. Toluene and volatile components were distilled off at 80 ° C. and 3 Torr to obtain Sample 1 (279 parts). This was a brown transparent liquid having a viscosity of 132 cP and an epoxy equivalent of 860. The weight ratio (resin amount) of the part derived from the organopolysiloxane having an OH group consisting of Me ₃ SiO _1/2 unit, SiO _4/2 unit, and (HO) SiO _3/2 unit in Sample 1 is 13%. .
[0048]
[Example 2]
147 parts of 60% toluene solution of organopolysiloxane having OH groups (M / Q = 0.70, OH group content 0.77% by weight), 12 parts of toluene used during dehydrogenative condensation reaction Sample 2 (339 parts) was obtained in the same manner as in Example 1 except that This was a brown transparent liquid with a viscosity of 308 cP and an epoxy equivalent of 803. The resin content of Sample 2 is 25%.
[0049]
Example 3
442 parts of 60% toluene solution of organopolysiloxane having OH groups (M / Q = 0.70, OH group content 0.77% by weight), 0 parts of toluene used during dehydrogenative condensation reaction Sample 3 (521 parts) was obtained by performing the same operation as in Example 1 except that. This was a brown transparent liquid with a viscosity of 11,600 cP and an epoxy equivalent of 1,550. The resin amount of sample 3 is 50%.
[0050]
Example 4
Sample 1 (100 parts) obtained in Example 1 and iodonium salt photoinitiator (1 part) were mixed to prepare a treatment liquid (silicone composition). The peel strength, residual adhesion rate, and silicone transferability of the cured film of this treatment solution were measured by the above evaluation methods. The results are shown in Table 1.
[0051]
Example 5
Sample 2 (100 parts) obtained in Example 2 and iodonium salt photoinitiator (1 part) were mixed to prepare a treatment liquid. The peel strength, residual adhesion rate, and silicone transferability of the cured film of this treatment solution were measured by the above evaluation methods. The results are shown in Table 1.
[0052]
Example 6
Sample 3 (100 parts) obtained in Example 3 and iodonium salt photoinitiator (1 part) were mixed to prepare a treatment liquid. The peel strength, residual adhesion rate, and silicone transferability of the cured film of this treatment solution were measured by the above evaluation methods. The results are shown in Table 1.
[0053]
[Comparative Example 1]
42 parts of a 60% toluene solution of organopolysiloxane having OH groups (M / Q = 0.70, OH group content 0.77% by weight), average composition formula Me ₃ SiO— (EMeSiO) ₄ — (Me ₂ SiO) ₂₄ -SiMe ₃
(E is β- (3,4-epoxycyclohexyl) ethyl group)
75 parts of an organopolysiloxane having an epoxy group represented by the above was mixed, and toluene and volatile components were distilled off at 80 ° C. and 3 Torr to obtain Sample 4 (98 parts). The resin amount of Sample 4 is 25%. Sample 4 (100 parts) and iodonium salt photoinitiator (1 part) were mixed to prepare a treatment liquid. The peel strength, residual adhesion rate, and silicone transferability of the cured film of this treatment solution were measured by the above evaluation methods. The results are shown in Table 1.
[0054]
[Comparative Example 2]
Me ₃ SiO— (EMeSiO) ₄ — (Me ₂ SiO) ₂₄ —SiMe ₃
(E is β- (3,4-epoxycyclohexyl) ethyl group)
An organopolysiloxane having an epoxy group represented by (100 parts) and an iodonium salt photoinitiator (1 part) were mixed to prepare a treatment solution. The peel strength, residual adhesion rate, and silicone transferability of the cured film of this treatment solution were measured by the above evaluation methods. The results are shown in Table 1.
[0055]
[Table 1]

Claims (3)

R ₃ SiO _1/2 unit, SiO _4/2 unit and (HO) SiO _3/2 unit (where R is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms) For the OH group of the OH group-containing organopolysiloxane, the following general formula (1) or (2)

(Wherein R ¹ represents the same or different unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, a is an integer of 0 to 3, p and r are integers of 2 or more, q, s is an integer of 0 or more.)
After the dehydrocondensation reaction using an excess amount of the SiH group of the organohydropolysiloxane represented by the above formula, the compound containing the SiH group remaining in the obtained reaction product, the epoxy group and the alkenyl group A method for producing an epoxy group-containing organopolysiloxane, which comprises an addition reaction with an alkenyl group. An ultraviolet curable composition comprising an epoxy group-containing organopolysiloxane produced by the method according to claim 1 and an onium salt photoinitiator. The ultraviolet curable composition according to claim 2, which is for release paper.