JP2004315731A - Room temperature curable polyorganosiloxane composition and its preparing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a room temperature curable polyorganosiloxane compound with good curability, excellent in imparting fluidity and in reduction in an extrusion force, and with less variation of viscosity and physical properties during long-term preservation. <P>SOLUTION: This room temperature curable polyorganosiloxane compound comprises a compound (A) of 100 pts.wt. such as a silicon functional polydiorganosiloxane having on average ≥2 hydrolyzable groups as a silicon functional group, a silica powder (B) of 1.0-200 pts.wt. having a specific surface area of 20-800 m<SP>2</SP>/g, a titanium chelate compound (C) of 0.5-15 pts.wt. as a curing catalyst and a titanium ester compound (D) of 0.01-3.0 wt%, based on the component (B), as a surface treating agent for the silica powder. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

で示される実質的に直鎖状のポリオルガノシロキサンである。
【００２９】
式中、Ｒ^１は互いに同一でも異なっていてもよい置換または非置換の１価の炭化水素基を表し、Ｒ^２は―ＺＳｉＲ^３ _３−ｐＸ_ｐを表す。ここで、Ｚは酸素および／または２価の炭化水素基を表し、Ｒ^３は互いに同一でも異なっていてもよい置換または非置換の１価の炭化水素基を表し、Ｘは加水分解性基であるアルコキシ基を表し、ｐは１〜３の数である。また、ｎは当該（Ａ）成分の２３℃における粘度を２０〜１，０００，０００ｍＰａ・ｓにする数である。末端基Ｒ^２は、ケイ素官能基である加水分解性基Ｘを少なくとも１個有するケイ素官能性シロキシ単位であり、（Ａ１）成分および（Ａ２）成分は、分子の両末端に、それぞれ上記の加水分解性基Ｘを少なくとも１個有する。
【００３０】
Ｒ^１は、互いに同一でも異なっていてもよい置換または非置換の１価の炭化水素基である。Ｒ^１としては、メチル基、エチル基、プロピル基、ブチル基、ペンチル基、ヘキシル基、オクチル基、デシル基、ドデシル基のようなアルキル基；ビニル基、アリール基のようなアルケニル基；フェニル基、トリル基、キシリル基のようなアリール基；２−フェニルエチル基、２−フェニルプロピル基のようなアラルキル基が例示され、さらにこれらの炭化水素基の水素原子の一部が他の原子または基で置換されたもの、すなわちクロロメチル基、３−クロロプロピル基、３，３，３−トリフルオロプロピル基のようなハロゲン化アルキル基；３−シアノプロピル基のようなシアノアルキル基などの置換炭化水素基が例示される。合成が容易であり、かつ（Ａ）成分が分子量の割に低い粘度を有し、硬化前の組成物に良好な押し出し性を与えること、および硬化後の組成物に良好な物理的性質を与えることから、全有機基の８５％以上がメチル基であることが好ましく、実質的にすべての有機基がメチル基であることがより好ましい。
【００３１】
一方、特に耐熱性、耐放射線性、耐寒性または透明性を組成物に付与する場合には、Ｒ^１の一部として必要量のフェニル基を、耐油性、耐溶剤性を付与する場合には、Ｒ^１の一部として３，３，３−トリフルオロプロピル基や３−シアノプロピル基を、また塗装適性を有する表面を付与する場合には、Ｒ^１の一部として長鎖アルキル基やアラルキル基を、それぞれメチル基と併用するなど、目的に応じて任意に選択することができる。
【００３２】
末端基Ｒ^２においてケイ素原子に結合するＲ^３は、互いに同一でも異なっていてもよく、またＲ^１と同一でも異なっていてもよい置換または非置換の１価の炭化水素基であり、Ｒ^１と同様なものが例示される。合成が容易で、加水分解性基Ｘの反応性が優れていることから、メチル基またはビニル基が好ましい。また、Ｚは、互いに同一でも異なっていてもよく、酸素原子ならびにメチレン基、エチレン基、トリメチレン基のようなアルキレン基；フェニレン基等の２価の炭化水素基が例示される。合成が容易なことから、酸素原子およびエチレン基が好ましく、酸素原子が特に好ましい。
【００３３】
Ｘは、末端基Ｒ^２に少なくとも１個存在するケイ素官能基、すなわち加水分解性基であるアルコキシ基である。このようなＸとしては、メトキシ基、エトキシ基、プロポキシ基、ブトキシ基のようなアルコキシ基；２−メトキシエトキシ基、２−エトキシエトキシ基のような置換アルコキシ基；イソプロペノキシ基のようなエノキシ基などが例示され、互いに同一でも異なっていても良い。合成の容易さ、硬化前の組成物の物性、保存中の安定性、硬化性、経済性、および広範囲の用途に用いられ、とりわけ電気電子部品の用途における耐腐食性を鑑みた場合、アルコシキ基が好ましい。
【００３４】
末端基Ｒ^２におけるケイ素官能基Ｘの数ｐは、１〜３であることが好ましい。
【００３５】
また、硬化前の組成物に適度の押し出し性を付与するとともに、硬化後のゴム状弾性体に優れた機械的特性を与えるために、（Ａ）成分（すなわち（Ａ１）成分あるいは（Ａ２）成分）を表す一般式におけるｎは、当該（Ａ）成分の２３℃における粘度が２０〜１，０００，０００ｍＰａ・ｓの範囲になるように選択される。（Ａ）成分の粘度が２０ｍＰａ・ｓ未満では、硬化後のゴム状弾性体の伸びが十分でなく、一方１，０００，０００ｍＰａ・ｓを超えると、均一な組成物が得にくく押し出し作業性も低下する。硬化前および硬化後の組成物に要求される性質がバランスよく得られることから、特に好ましい粘度は５００〜２００，０００ｍＰａ・ｓの範囲である。
【００３６】
架橋剤を用いなくとも硬化するタイプの室温硬化性ポリオルガノシロキサン組成物においては、上記（Ａ）成分すなわち（Ａ１）成分中のＸが架橋手段となり、架橋剤がなくても架橋反応が進行し、硬化してゴム状弾性体を生じる。好ましいＸとしては、メトキシ基のようなアルコキシ基；アセトキシ基のようなアシロキシ基；およびメチルエチルケトキシマト基が例示されるが、耐腐食性の観点からアルコキシ基が好ましい。このような（Ａ１）成分をベースポリマーとして使用することにより、硬化前の組成物が安定化されるとともに、優れた硬化性が得られる。
【００３７】
また、架橋剤を用いて硬化させるタイプの室温硬化性ポリオルガノシロキサン組成物においては、（Ａ２）成分を架橋剤と組合わせて用いることにより、架橋構造を形成させる。（Ａ２）成分としては、Ｘが水酸基であるか、ｐが１（すなわち、分子中に水酸基および／または上記と同様の加水分解性基である２個のＸを有する）のものを用いることができる。
【００３８】
このような（Ａ２）成分と組合わせて使用される架橋剤としては、水および硬化触媒の存在下に（Ａ２）成分中のケイ素官能性基Ｘと反応し、組成物を硬化させるためのケイ素官能性基を有するケイ素化合物、および／またはその部分加水分解縮合物が用いられる。
【００３９】
この架橋剤は、一般式：Ｒ^４ _４−ｑＳｉＹ_ｑ
（式中、Ｒ^４は互いに同一でも異なっていてもよい置換または非置換の１価の炭化水素基を表し、Ｙは加水分解性基を表す。またｑは、平均２を超え、４以下の数である。）で示される。
【００４０】
Ｒ^４としては、（Ａ）成分のケイ素原子に直接結合した有機基Ｒ^１と同様な基を例示することができる。入手のしやすさと優れた架橋反応速度が得られることから、メチル基またはビニル基が好ましい。また、加水分解反応性基Ｙとしては、（Ａ）成分の末端基に存在するＸとして挙げられたものと同様のものが例示される。
【００４１】
このような架橋剤の例としては、テトラメトキシシラン、メチルトリメトキシシラン、ビニルトリメトキシシラン、フェニルトリメトキシシラン、テトラエトキシシラン、メチルトリエトキシシラン、ビニルトリエトキシシラン、フェニルトリエトキシシラン、テトラプロポキシシラン、テトライソプロポキシシランおよびそれらの部分加水分解縮合物のようなアルコキシ基含有化合物；テトラキス（２−エトキシエトキシ）シラン、メチルトリス（２−メトキシエトキシ）シラン、ビニル（２−エトキシエトキシ）シラン、フェニルトリス（２−メトキシエトキシ）シランおよびそれらの部分加水分解縮合物のような置換アルコキシ基含有化合物；メチルトリイソプロペノキシシラン、ビニルトリイソプロペノキシシラン、フェニルトリイソプロペノキシシラン、ジメチルジイソプロペノキシシラン、メチルビニルジイソプロペノキシシランおよびそれらの部分加水分解縮合物のようなエノキシ基含有化合物などが例示される。ｑが２であるシランのみであると（Ａ）成分が（Ａ２）である場合、鎖長が延長されるのみで架橋構造が形成されず、ゴム硬化物が生成じ得ない。したがって、ｑが２であるシランのみを用いるのではなく、ｑが３または４であるシランと併用される。（Ａ）成分が（Ａ１）であり、かつ前記した一般式［化１］の加水分解性基であるＸを１分子中に３個以上有している場合は、この限りでない。
【００４２】
合成が容易で、組成物の保存安定性を損なうことがなく、しかも大きな架橋反応速度すなわち大きな硬化速度を与えることを考慮すると、これらのシラン化合物の中で、テトラメトキシシラン、テトラエトキシシラン、メチルトリメトキシシラン、ビニルトリメトキシシラン、メチルトリス（イソプロペノキシ）シラン、ビニルトリス（イソプロペノキシ）シランおよびそれらの部分加水分解縮合物を用いることが好ましい。
【００４３】
なお、（Ａ）成分として、前記した（Ａ１）成分であるＸが加水分解性基でｐが平均１を超えるものを用いる場合は、前記したように架橋剤がなくても硬化が可能であるが、このような場合においても、組成物の硬化性と、硬化して得られるゴム状弾性体の機械的性質とをバランスよく実現するために、前記の架橋剤を併用することが好ましい。さらに、加水分解性基ＹがＸと同じである架橋剤を用いることがより好ましい。
【００４４】
架橋剤の配合量は、（Ａ）成分１００重量部に対して、通常０．１〜１５重量部であり、好ましくは０．３〜１０重量部である。０．１重量部未満では架橋が十分に行われず、硬度の低い硬化物しか得られないばかりでなく、架橋剤を配合した組成物の保存安定性が悪くなる。一方、１５重量部を超えて配合すると、経済的に無意味であるばかりか、組成物の硬化性および硬化後の機械的特性とのバランスが著しく低下するため好ましくない。
【００４５】
本発明においては、先に具体例を列挙したような、Ｒ^４として１価の炭化水素基を有するケイ素官能性化合物の他、置換された１価の炭化水素基を有する炭素官能性の同様な化合物を、架橋剤の一部または全部として用いてもよい。このようなＲ^４としては、置換のアミノ基、エポキシ基、イソシアナト基、（メタ）アクリロキシ基、メルカプト基、またはハロゲン原子で置換されたアルキル基やフェニル基が例示される。置換アルキル基としては、置換メチル基、３−置換プロピル基、４−置換ブチル基が例示されるが、合成が容易なことから、３−置換プロピル基が好ましい。
【００４６】
このようなＲ^４を有する化合物としては、３−アミノプロピルトリメトキシシラン、３−アミノプロピルトリエトキシシラン、３−アミノプロピルトリイソプロポキシシラン、３−アミノプロピルトリアセトアミドシラン、Ｎ−（２−アミノエチル）−３−アミノプロピルトリメトキシシラン、Ｎ−（２−アミノエチル）−３−アミノプロピルトリエトキシシラン、Ｎ−メチル−３−アミノプロピルトリメトキシシラン、Ｎ−フェニル−３−アミノプロピルトリメトキシシラン、Ｎ，Ｎ−ジメチル−３−アミノプロピルトリメトキシシランのような置換または非置換のアミノ基含有シラン；３−グリシドキシプロピルトリメトキシシラン、３−グリシドキシプロピルメチルジメトキシシラン、３，４−エポキシシクロヘキシルエチルトリメトキシシランのようなエポキシ基含有シラン；３−イソシアナトプロピルトリメトキシシラン、３−イソシアナトプロピルメチルジメトキシシラン、３−イソシアナトプロピルトリエトキシシランのようなイソシアナト基含有シラン；３−アクリロキシプロピルトリメトキシシラン、３−メタクリロキシプロピルトリメトキシシラン、３−アクリロキシプロピルメチルジメトキシシラン、３−メタクリロキシプロピルメチルジメトキシシランのような（メタ）アクリロキシ基含有シラン；３−メルカプトプロピルトリメトキシシランのようなメルカプト基含有シラン；および３−クロロプロピルトリメトキシシランのようなハロゲン原子含有シランが例示される。
【００４７】
また、前述のイソシアナト基含有シランのイソシアナト基がシクロ環（トリアジン−トリオン）を形成したトリス（Ｎ−トリメトキシプロピル）イソシアヌレート、トリス（Ｎ−トリエトキシプロピル）イソシアヌレート、トリス（Ｎ−メチルジメトキシプロピル）イソシアヌレートも接着向上成分として、同様に用いられる。
【００４８】
このような置換炭化水素基含有シランや前記のビニル基含有シランは、炭素官能性シランであって、これらを配合することにより、組成物が硬化する際の各種基材への接着性を向上させることができる。なお、炭素官能性シランの配合は、組成物の硬化性、貯蔵安定性および物理的特性を損なわない限り可能であるが、多量のアミノアルキル基含有シランおよびメルカプト基含有シランの配合は、（Ｃ）成分であるチタンキレート化合物を被毒し、その触媒機能を著しく低下させるため、貯蔵安定性の面から好ましくない。
【００４９】
炭素官能性シランの配合量は、（Ａ）成分１００重量部に対して０．０５〜１５重量部が好ましく、０．１〜１０重量部がさらに好ましい。０．０５重量部未満では接着性の向上効果が少なく、またその発現が遅い。また、１５重量部を超えて配合すると、前記した問題点のほか、保存安定性と作業性が悪くなり、また黄変現象を生じるため好ましくない。
【００５０】
本発明において（Ｂ）成分のシリカ粉末は、ポリオルガノシロキサン組成物をゴム状態あるいはゲル状態に硬化させた場合の補強材であり、２０〜８００ｍ^２／ｇの比表面積を有する。シリカ粉末の比表面積が２０ｍ^２／ｇ未満である場合には、補強性が不十分である。また、比表面積が８００ｍ^２／ｇを超えると、粉末同士の凝集性が大きすぎるため、本発明の組成物に適さない。これらのシリカ粉末の中でも、機械的強度の点から、５０ｍ^２／ｇ以上の比表面積を有するものが好ましく、さらに製造上および入手の容易さの観点から、５００ｍ^２／ｇ以下の比表面積を有するシリカ粉末の使用が好ましい。
【００５１】
このようなシリカ粉末としては、煙霧質シリカ、湿式シリカ、溶融シリカ等が例示され、その１種または２種以上を併用してもよい。（Ｂ）成分であるシリカ粉末の配合量は、（Ａ）成分１００重量部に対して１．０〜２００重量部とし、より好ましくは３．０〜５０重量部とする。シリカ粉末の配合量が１．０重量部未満では、得られる硬化物の機械的強度が不十分であり、また２００重量部を超えると、混合が困難であり均一な組成物が得られない。また、このようなシリカ粉末は、処理済み、未処理を問わず使用することができるが、本発明において、トリメチルシリル基で処理したもののうちで処理度が高いものは、効果が低い場合がある。
【００５２】
本発明において（Ｃ）成分の硬化触媒であるチタンキレート化合物は、（Ａ）成分自体の架橋手段として含有される加水分解性基のＸ同士、および／または（Ａ）成分の加水分解性基Ｘと架橋剤の加水分解性基Ｙとを、水分の存在下に反応させて架橋構造を形成させ、ゴム状弾性体を得るための硬化触媒である。アルキルアセチルアセテートを配位子として有するチタンキレート化合物の使用が好ましい。
【００５３】
このような（Ｃ）成分としては、ジイソプロポキシチタンビス（メチルアセチルアセテート）、ジイソプロポキシチタンビス（エチルアセチルアセテート）、ジイソプロポキシチタンビス（ブチルアセチルアセテート）、ジブトキシチタンビス（メチルアセチルアセテート）、ジブトキシチタンビス（エチルアセチルアセテート）、ジイソプロポキシチタンビス（ブチルアセチルアセテート）、ジイソプロポキシチタンビス（２−エチルヘキシルアセチルアセテート）、ジイソプロポキシチタンビス（２−エチルヘキシルアセチルアセテート）、ジイソプロポキシチタンビス（２−エチルヘキシルアセチルアセテート）、ジブトキシチタンビス（２−エチルヘキシルアセチルアセテート）、ジブトキシチタンビス（２−エチルヘキシルアセチルアセテート）、ジイソプロポキシチタンビス（２−エチルヘキシルアセチルアセテート）、ジイソプロポキシチタンビス（アセチルアセテート）、ジイソプロポキシチタンビス（アセチルアセテート）、ジイソプロポキシチタンビス（アセチルアセテート）、ジブトキシチタンビス（アセチルアセテート）、ジブトキシチタンビス（アセチルアセテート）、ジイソプロポキシチタンビス（アセチルアセテート）のようなチタンキレート化合物が例示される。
【００５４】
耐腐食性、硬化促進性および入手のし易さから、前記化合物のうちで、ジイソプロポキシチタンビス（メチルアセチルアセテート）、ジイソプロポキシチタンビス（エチルアセチルアセテート）、ジイソプロポキシチタンビス（ブチルアセチルアセテート）、ジイソプロポキシチタンビス（２−エチルヘキシルアセチルアセテート）等が好ましい。
【００５５】
（Ｃ）成分の配合量は、（Ａ）成分１００重量部あたり０．５〜１５重量部、より好ましくは１．０〜１０重量部である。０．５重量部未満では、硬化触媒として十分に作用せず、硬化に長い時間がかかるばかりでなく、特に空気との接触面から遠いゴム層の深部における硬化が不十分となり、反対に１５重量部を超える場合には、その配合量に見合う効果がなく無意味であるばかりでなく、経済的にも不利益となり好ましくない。
【００５６】
本発明の（Ｄ）成分の表面処理剤および表面処理促進剤であるチタンエステル化合物は、シリカ粉末の表面処理剤として、および（Ａ）成分とシリカ粉末との混合を容易にするための表面促進剤としての作用を有するものである。（Ｄ）成分中の反応性基であるアルコキシ基により、シリカ粉末表面のシラノール基が処理されるばかりでなく、（Ｄ）成分中の反応性基により（Ａ）成分中の反応性基とシリカ粉末表面のシラノールとの反応が適度に促進されることにより、（Ａ）成分によってもシリカ粉末表面のシラノール基が処理される。
【００５７】
こうして、組成物に流動性が付与され、押し出し力の低減が可能となる。また、シリカ粉末表面のシラノール基を処理することにより、経時的に硬化性の低下や増粘を引き起こすことなく、貯蔵安定性に優れた組成物を得ることができる。
【００５８】
このようなチタンエステル化合物として、イソプロピルトリオクタノイルチタネート、イソプロピルジメタクリルイソステアロイルチタネート、イソプロピルジアクリルイソステアロイルチタネート、ジイソステアロイルエチレンチタネート、イソプロピルトリイソステアロイルチタネートのようなカルボン酸エステル、イソプロピルトリドデシルベンゼンスルホニルチタネートのようなスルホン酸エステル、イソプロピルトリス（ジオクチルバイロホスフェート）チタネート、ビス（ジオクチルバイロホスフェート）オキシアセテートチタネート、ビス（ジオクチルバイロホスフェート）エチレンチタネート、イソプロピルトリ（ジオクチルホスフェート）チタネートのようなリン酸エステル、テトライソプロピルビス（ジオクチルホスファイト）チタネート、テトラオクチルビス（ジトリデシルホスファイト）チタネートのような亜リン酸エステルが例示される。表面処理の効果、取り扱いの容易さおよび入手のし易さから、カルボン酸エステル、リン酸エステルおよび亜リン酸エステルが好ましい。また、耐腐食性の観点から、カルボン酸エステルの使用がさらに好ましい。さらに、カルボン酸部位の炭素数は、表面処理の効果および得られる組成物における相溶性の観点から、２０以下が好ましく、さらに耐腐食性の観点から炭素数４以上が好ましい。
【００５９】
（Ｄ）チタンエステル化合物の配合量は、（Ｂ）成分であるシリカ粉末に対して０．０１〜３．０重量％の割合とする。表面処理の効率の点から０．０５重量％以上が好ましく、また得られるベースコンパンドの貯蔵安定性の観点から２．０重量％以下がさらに好ましい。
【００６０】
本発明の室温硬化性ポリオルガノシロキサン組成物には、硬化前の組成物に適度の流動性を与えるとともに、硬化して得られるゴム状弾性体に、例えばシーリング材、接着剤、現場成形ガスケットなどとして用いる場合に要求される高い機械的強度を付与するために、前記した（Ｂ）成分であるシリカ粉末以外に、通常用いられている充填剤を配合することができる。
【００６１】
このような充填剤としては、沈殿シリカ、煙霧質酸化チタンのような補強性充填剤、けいそう土、粉砕シリカ、アルミノケイ酸、酸化亜鉛、酸化アルミニウム、炭酸カルシウム、有機酸表面処理炭酸カルシウム、炭酸マグネシウム、ケイ酸カルシウム、タルク、酸化第二鉄のような非補強性充填剤が例示され、硬化後のゴム状弾性体に要求される物性に応じて選択される。なお、これらの充填剤の表面をオルガノクロロシラン類、ポリオルガノシロキサン類、ヘキサメチルジシラザンなどで表面処理しても良いが、充填剤の表面処理を行う場合には、過剰となった表面処理剤および表面処理剤が反応して生成した副生成物を組成物中から除く必要がある。これら表面処理剤およびその副生成物が組成物中に存在すると、長期間保存で粘度や物理的特性の変化が少ないという本願の目的が達成できない場合がある。
【００６２】
また、例えば透明性が要求される場合には、煙霧質シリカを用いることが好ましく、建築用シーリング材として、とりわけ低モジュラスが要求される場合には、非補強性の充填剤を用いることが好ましい。上記の充填剤のうちで、補強性充填剤の量が少なすぎると、機械的特性の向上の効果がほとんど現れず、逆に多すぎる場合には、モジュラスが大きくなりすぎて破断時の伸びが小さくなる。前記したシリカ粉末以外の充填剤の添加量は、（Ａ）成分１００重量部に対して１〜２００重量部が好ましく、５〜１００重量部の範囲がより好ましい。
【００６３】
さらに、本発明の組成物には、目的に応じて、顔料、チクソトロピー性付与剤、押し出し作業性を改良するための粘度調整剤、紫外線吸収剤、防かび剤、耐熱性向上剤、難燃化剤など、各種の添加剤を加えても良い。
【００６４】
本発明の組成物は、以上の全ての成分および必要に応じて各種添加剤を、湿気を遮断した状態で混合することにより得られる。なお、（Ｄ）成分であるチタンエステル化合物の添加順に関しては、系内に均一に分散可能でかつシリカ粉末の表面を十分均一に処理することができるように、また硬化触媒による硬化物の形成への影響を少なくするためにも、（Ｃ）成分を混合する以前に、混合混練前の（Ａ）成分に（Ｄ）成分を最初に添加するか、あるいは（Ａ）成分と（Ｂ）成分との混合混練時に（Ｄ）成分を添加することが望ましい。
【００６５】
得られた組成物は、密閉容器中でそのまま保存し、使用時に空気中の水分に曝すことによってはじめて硬化する、いわゆる１包装型室温硬化性組成物として使用することができる。また、本発明の組成物を、例えば架橋剤と硬化触媒を分けた組成物として調製し、適宜２〜３個の別々の容器に分けて保存し、使用時にこれらを混合する、いわゆる多包装型室温硬化性組成物として使用することもできる。
【００６６】
本発明により得られる室温硬化性ポリオルガノシロキサン組成物は、湿気の存在しない密封条件下では安定であり、空気中の水分と接触することにより、室温で硬化してゴム状弾性体を生じる。特に本発明は、従来品より優れた硬化性を有し、貯蔵安定性に優れる室温硬化性ポリオルガノシロキサンを提供する。
【００６７】
以下、実施例を挙げて本発明を具体的に説明するが、本発明は実施例に限定されるものではない。なお、実施例中、部とあるのはいずれも重量部を表し、粘度などの物性値は全て２３℃、相対湿度５０％での値を示す。
【００６８】
実施例１
粘度１，０００ｍＰａ・ｓのα，ω−ビス（メチルジメトキシシロキシ）ポリジメチルシロキサン１００部に、シリカ粉末の表面処理剤であるイソプロピルトリイソステアロイルチタネート０．１４部を加え、常温で１５分間均一に混合した後、比表面積が１５０ｍ^２／ｇの煙霧質シリカ１４部とともに万能混合機に仕込み、常温で１時間均一に混練した。次に、８０〜１００℃で３０分間加熱減圧下で混練を行い、均一なベースコンパンドＢ−１を得た。次いで、得られたベースコンパンドＢ−１の１１４部に、メチルトリメトキシシラン３．０部、トリス（Ｎ−トリメトキシプロピル）イソシアヌレート０．５部およびジイソプロポキシチタンビス（エチルアセチルアセテート）２．５部を加え、湿気遮断下で均一に混合し、ポリオルガノシロキサン組成物１を得た。
【００６９】
実施例２
粘度１，０００ｍＰａ・ｓのα，ω−ビス（メチルジメトキシシロキシ）ポリジメチルシロキサン１００部に、シリカ粉末の表面処理剤であるテトライソプロピルビス（ジオクチルホスファイト）チタネート０．１４部を加え、常温で１５分間均一に混合した後、比表面積が１５０ｍ^２／ｇの煙霧質シリカ１４部とともに万能混合機に仕込み、常温で１時間均一に混練した。次に、８０〜１００℃で３０分間加熱減圧下で混練を行い、均一なベースコンパンドＢ−２を得た。次いで、得られたベースコンパンドＢ−２の１１４部に、メチルトリメトキシシラン３．０部、トリス（Ｎ−トリメトキシプロピル）イソシアヌレート０．５部およびジイソプロポキシチタンビス（エチルアセチルアセテート）２．５部を加え、湿気遮断下で均一に混合しポリオルガノシロキサン組成物２を得た。
【００７０】
実施例３
粘度２０，０００ｍＰａ・ｓのα，ω−ビス（メチルジメトキシシロキシ）ポリジメチルシロキサン１００部に、テトライソプロピルビス（ジオクチルホスファイト）チタネート０．１５部を加え、常温で１５分間均一に混合した後、比表面積が２００ｍ^２／ｇの煙霧質シリカ１５部とともに万能混合機に仕込み、常温で１時間均一に混練した。次に、８０〜１００℃で３０分間加熱減圧下で混練を行い、均一なベースコンパンドＢ−３を得た。次いで、得られたベースコンパンドＢ−３の１１５部に、メチルトリメトキシシラン２．０部、トリス（Ｎ−トリメトキシプロピル）イソシアヌレート０．５部およびジイソプロポキシチタンビス（エチルアセチルアセテート）２．０部を加え、湿気遮断下で均一に混合しポリオルガノシロキサン組成物３を得た。
【００７１】
実施例４
粘度２０，０００ｍＰａ・ｓのα，ω−ビス（メチルジメトキシシロキシ）ポリジメチルシロキサン１００部に、テトライソプロピルビス（ジオクチルホスファイト）チタネート０．１５部を加え、常温で１５分間均一に混合した後、比表面積が２００ｍ^２／ｇのオクタメチルシクロテトラシロキサンで処理された煙霧質シリカ１５部とともに万能混合機に仕込み、常温で１時間均一に混練した。次に、８０〜１００℃で４５分間加熱減圧下で混練を行い、均一なベースコンパンドＢ−４を得た。次いで、得られたベースコンパンドＢ−４の１１５部に、メチルトリメトキシシラン２．０部、トリス（Ｎ−トリメトキシプロピル）イソシアヌレート０．５部およびジイソプロポキシチタンビス（エチルアセチルアセテート）２．０部を加え、湿気遮断下で均一に混合しポリオルガノシロキサン組成物４を得た。
【００７２】
実施例５
シリカ粉末の表面処理剤として、テトライソプロピルビス（ジオクチルホスファイト）チタネートの代わりに、イソプロピルトリイソステアロイルチタネートを用い、実施例４と同様にしてベースコンパンドＢ−５を得た。次いで、得られたベースコンパンドＢ−５の１１５部に、メチルトリメトキシシラン２．０部、トリス（Ｎ−トリメトキシプロピル）イソシアヌレート０．５部およびジイソプロポキシチタンビス（エチルアセチルアセテート）２．０部を加え、湿気遮断下で均一に混合しポリオルガノシロキサン組成物５を得た。
【００７３】
比較例１
粘度１，０００ｍＰａ・ｓのα，ω−ビス（メチルジメトキシシロキシ）ポリジメチルシロキサン１００部に、比表面積が１５０ｍ^２／ｇの煙霧質シリカ１４部を加えたものを万能混合機に仕込み、常温で１５分間均一に混合した後、さらに常温で１時間均一に混練した。次いで、８０〜１００℃で３０分間加熱減圧下で混練を行い、均一なベースコンパンドＣ−１を得た。次いで、得られたベースコンパンドＣ−１の１１４部に、メチルトリメトキシシラン３．０部、トリス（Ｎ−トリメトキシプロピル）イソシアヌレート０．５部およびジイソプロポキシチタンビス（エチルアセチルアセテート）２．５部を加え、湿気遮断下で均一に混合し比較組成物１を得た。
【００７４】
比較例２
粘度１，０００ｍＰａ・ｓのα，ω−ビス（メチルジメトキシシロキシ）ポリジメチルシロキサン１００部に、従来からのシリカ粉末の表面処理剤であるテトラブトキシチタン０．１４部を加え、常温で１５分間均一に混合した後、比表面積が１５０ｍ^２／ｇの煙霧質シリカ１４部とともに万能混合機に仕込み、常温で１時間均一に混練した。次に、８０〜１００℃で３０分間加熱減圧下で混練を行い、均一なベースコンパンドＣ−２を得た。次いで、得られたベースコンパンドＣ−２の１１４部に、メチルトリメトキシシラン３．０部、トリス（Ｎ−トリメトキシプロピル）イソシアヌレート０．５部およびジイソプロポキシチタンビス（エチルアセチルアセテート）２．５部をさらに加え、湿気遮断下で均一に混合し比較組成物２を得た。
【００７５】
比較例３
テトラブトキシチタンの代わりにジイソプロポキシチタンビス（エチルアセチルアセテート）０．１４部を用い、比較例２と同様にして均一なベースコンパンドＣ−３を得た。次いで、得られたベースコンパンドＣ−３の１１４部に、メチルトリメトキシシラン３．０部、トリス（Ｎ−トリメトキシプロピル）イソシアヌレート０．５部およびジイソプロポキシチタンビス（エチルアセチルアセテート）２．５部を加え、湿気遮断下で均一に混合し比較組成物３を得た。
【００７６】
比較例４
テトラブトキシチタンの代わりに３−アミノプロピルトリエトキシシラン０．２部を用い、比較例２と同様にして均一なベースコンパンドＣ−４を得た。次いで、得られたベースコンパンドＣ−４の１１４部に、メチルトリメトキシシラン３．０部、トリス（Ｎ−トリメトキシプロピル）イソシアヌレート０．５部およびジイソプロポキシチタンビス（エチルアセチルアセテート）２．５部を加え、湿気遮断下で均一に混合し比較組成物４を得た。
【００７７】
比較例５
表面処理剤であるチタンエステル化合物を用いなかった以外は実施例４と同様にして、ベースコンパンドＣ−５を得た。次いで、得られたベースコンパンドＣ−５の１１５部に、メチルトリメトキシシラン２．０部、トリス（Ｎ−トリメトキシプロピル）イソシアヌレート０．５部およびジイソプロポキシチタンビス（エチルアセチルアセテート）２．０部を加え、湿気遮断下で均一に混合し比較組成物５を得た。
【００７８】
次に、実施例１〜５および比較例１〜５で調製し密封して保存したポリオルガノシロキサン組成物について、指触乾燥時間、物理的特性、保存安定性、接着性を、実施例１〜３および比較例１〜４については粘度を、実施例４〜５および比較例５については押し出し力を、それぞれ測定し評価した。
【００７９】
また、実施例１〜３および比較例１〜４で得られたベースコンパンドについて、外観、収量、粘度および経時後の粘度を調べるとともに、経時後のベースコンパンドを用いて得られた組成物に関して、外観、粘度と指触乾燥時間および物理的特性を測定した。
【００８０】
なお、指触乾燥時間、物理的特性、保存安定性、接着性および押し出し力の測定は、それぞれ以下に示すようにして行った。
【００８１】
（ａ）指触乾燥時間：組成物を２３℃、５０％ＲＨの雰囲気中に押し出した後、指で表面に接触して乾燥状態にあることを確認するに至る時間を測定した。
【００８２】
（ｂ）物理的特性：組成物を厚さ２ｍｍのシート状に押し出し、得られたシートを２３℃、５０％ＲＨで１６８時間放置して空気中の湿気により硬化させ、硬化物の物理的特性をＪＩＳ Ｋ６３０１により測定した。
【００８３】
（ｃ）保存安定性：湿気を遮断した容器に組成物を入れ、７０℃で５日間加熱した後、指触乾燥時間および粘度を２３℃、５０％ＲＨの雰囲気で測定した。また、厚さ２ｍｍのシート状に押し出し、これを２３℃、５０％ＲＨで１６８時間放置して空気中の湿気により硬化させ、硬化物の物理的特性を前記（ｂ）と同様にＪＩＳ Ｋ６３０１により測定した。
【００８４】
（ｄ）接着性：ＪＩＳ Ｋ ６３０１の方法により、アルミニウム、ガラス、ポリカーボネート、フェノール樹脂をそれぞれ被着体として、引張り剪断強さおよび凝集破壊率を測定した。
【００８５】
（ｅ）押し出し力：実際に市販されている３３３ＭＬのカートリッジを用い、ノズルの先端を内径６．２ｍｍに調整したものを装着し、カートリッジの底部のプランジャーを押し出す力をオートグラフにより測定した。
【００８６】
これらの測定結果を表１および表２に示す。
【００８７】
【表１】

【００８８】
【表２】

【００８９】
表１および表２からわかるように、実施例１〜５で調製されたポリオルガノシロキサン組成物は、保存安定性に優れ、湿気の存在しない密封条件下で安定であるうえに、空気中の水分と接触することによりはじめて室温で硬化する。また、貯蔵により硬化性が低下することがなく、接着性が良好で物理的特性に優れたゴム状弾性体が得られる。
【００９０】
【発明の効果】
以上の記載から明らかなように、本発明の室温硬化性ポリオルガノシロキサン組成物は、湿気の存在しない密封条件下では安定であり、空気中の水分と接触することにより室温で硬化して、機械的特性が良好で優れた接着耐久性を有するゴム状弾性体を生じる。また、優れた貯蔵安定性を有し、長期間の貯蔵によっても硬化性が低下することがない。したがって、シーリング材、接着剤、現場成形ガスケットなどとして好適する。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a room temperature-curable polyorganosiloxane composition and a method for preparing the same, and more particularly to a polyorganosiloxane composition which cures at room temperature by contact with moisture in the air to produce a rubbery elastic body or a gel state. It relates to the manufacturing method.
[0002]
[Prior art]
In general, it is known that silica powder is compounded as a filler with a polyorganosiloxane that can be converted into a rubber or gel by a curing reaction in order to improve mechanical strength. However, since the silica powder has a free hydroxyl group, if the silica filler is added to the polyorganosiloxane as it is, the uncured polyorganosiloxane composition during storage has a thickening phenomenon and the formation of a structure with the passage of time. May cause creep hardening phenomenon.
[0003]
In order to solve these technical problems, many studies have been made on surface treatment of silica powder as a filler. One of the earliest methods attempted for surface treatment was to remove all hydroxyl groups by heating the silica powder to a very high temperature, i.e. a temperature above 200 <0> C.
[0004]
However, it has been found that silica powders tend to form agglomerates and are no longer free flowing. It was also found that when such a silica powder was cooled to room temperature, it exhibited a high degree of hygroscopicity and easily absorbed moisture from the atmosphere. Therefore, it was very difficult to process the silica powder as described above.
[0005]
In addition, a method of treating silica powder with a cyclic siloxane has been proposed (see, for example, Patent Document 1). In this method, the cyclic siloxane is split in the treatment step and combines with the free hydroxyl group to form a free hydroxyl group of the silica. The reactivity will be lost. Thus, a composition that is less prone to structuring (structure formation) is obtained by this method. Further, a silicone rubber having high physical properties can be obtained by the silica powder thus treated.
[0006]
Furthermore, a method in which silica powder is simultaneously treated with a monoalkoxysilane such as phenyldimethylethoxysilane and a primary organic amine compound in a solvent (for example, see Patent Document 2), or a pretreatment with an ammonia derivative followed by various treatments (For example, refer to Patent Document 3), and these methods have an advantage that free hydroxyl groups of silica powder can be satisfactorily treated.
[0007]
Further, a method has been developed in which silica powder is simultaneously treated with three treatment agents, hydroxylamine, cyclic siloxane, and silyl nitrogen compound. According to this method, for some applications, the storage stability of the composition is improved and the desired physical properties are obtained.
[0008]
In addition, a technique has been proposed in which fine powdered silica treated with an organosilazane is blended with an organohydrogenpolysiloxane to prevent discoloration during heating and vulcanization. (For example, see Patent Document 5)
[0009]
Furthermore, there has been proposed a method of obtaining a composition having excellent storage stability by in-process treatment of silica powder with a monosilanol or silazane compound together with a polyorganosiloxane. (For example, see Patent Document 6)
[0010]
Furthermore, a method has been proposed in which silica powder is in-process treated with an amino group-containing silicon compound together with a polyorganosiloxane. (See, for example, Patent Document 7) By this method, it is possible to obtain a room-temperature-curable polyorganosiloxane composition which does not cause a disadvantage in properties even if the treating agent remains and has excellent storage stability. Has been described.
[0011]
[Patent Document 1]
U.S. Pat. No. 2,938,009
[Patent Document 2]
U.S. Pat. No. 3,024,126
[Patent Document 3]
U.S. Pat. No. 3,635,743
[Patent Document 4]
JP-A-49-98861
[Patent Document 5]
JP-A-53-141362
[Patent Document 6]
Japanese Patent Publication No. 4-22179
[Patent Document 7]
JP-A-8-104816
[0012]
[Problems to be solved by the invention]
However, in the method described in Patent Document 1, there is a problem that the workability of the composition deteriorates with time because only a part of the free hydroxyl groups is bound or eliminated.
[0013]
Further, the method described in Patent Document 2 or Patent Document 3 cannot obtain a silicone rubber composition having desired physical properties.
[0014]
Further, in the method described in Patent Document 4, it is difficult to remove the silyl nitrogen compound and its decomposed product, so that the storage stability of the obtained composition is insufficient, and the viscosity only increases with time. Thus, there was a problem that the physical properties after curing were insufficient.
[0015]
Further, even with the method described in Patent Document 5, a composition sufficiently satisfactory in terms of storage stability of the composition could not be obtained.
[0016]
Furthermore, the method described in Patent Document 6 cannot be applied to the case where the reactive group of the polyorganosiloxane is a silanol group, and furthermore, ammonia or ammonia generated by decomposition of the remaining excess treating agent and silazane compound is not applicable. Not only did it take much time and steps to remove the ammonia derivative, but the ammonia odor could not be completely removed. Furthermore, if ammonia or an ammonia derivative remains, it causes corrosion to electric and electronic component materials such as copper-based metals, and there is a problem that it is difficult to use such materials and the like.
[0017]
Furthermore, even in the method described in Patent Document 7, a room-temperature-curable polyorganosiloxane composition having sufficiently satisfactory and excellent characteristics in response to recent miniaturization of electronic and electric components and changes in electrode members is disclosed. It was difficult to get.
[0018]
That is, in recent years, there has been a concern that an organotin compound is an environmental hormone or the like, and its use is restricted in many aspects. Therefore, even in the method described in Patent Document 7, an alkoxytin compound is used instead of an organotin compound as a curing catalyst. It is conceivable to use a titanium compound. However, in a method in which the silica powder is in-processed with an amino group-containing silicon compound, when an alkoxytitanium-based compound is blended as a curing catalyst, the amino group of the amino group-containing silicon compound coordinates with the alkoxytitanium-based compound to act as a catalyst. There is a problem that the curability of the composition is greatly adversely affected, for example, by inhibiting (poisoning) the composition and significantly reducing the activity as a curing catalyst. Further, since the catalytic activity of the alkoxytitanium compound is lower than that of the organotin compound, the compounding amount has to be increased, and when the alkoxytitanium compound contains a carboxy group in the ligand, the amino group described above is used. There is a problem that coloring and discoloration may occur.
[0019]
The present invention has been made to solve these problems, has good curability, imparts fluidity, excels in workability such as reduction of extrusion force, and has a small change in viscosity even when stored for a long time. Another object of the present invention is to provide a room temperature-curable polyorganosiloxane composition which does not impair physical properties.
[0020]
[Means for Solving the Problems]
The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, silica powder was subjected to in-process treatment using a titanium ester compound which is a surface treatment agent and a surface treatment accelerator together with a polyorganosiloxane. It has been found that a polyorganosiloxane composition having excellent storage stability can be obtained without lowering the activity of the alkoxytitanium compound as a curing catalyst by the remaining treating agent.
[0021]
That is, the room temperature-curable polyorganosiloxane composition of the present invention comprises (A) (A1) a silicon-functional polydiorganosiloxane having an average of more than two hydrolyzable groups as silicon functional groups in a molecule, and / or Or (A2) a room-temperature-curable polyorganosiloxane composition comprising a polyorganosiloxane comprising a silicon-functional polydiorganosiloxane having two or more silicon functional groups in a molecule and a crosslinking agent, wherein the (A) (B) Specific surface area of 20 to 800 m per 100 parts by weight of organosiloxane²/ G of 1.0 to 200 parts by weight of silica powder and (C) 0.5 to 15 parts by weight of a titanium chelate compound as a curing catalyst, and (D) a surface treatment agent and a surface treatment accelerator for silica powder. It is characterized in that a certain titanium ester compound is contained at a ratio of 0.01 to 3.0% by weight based on the silica powder (B).
[0022]
The room temperature-curable polyorganosiloxane composition of the present invention may contain 0.05 to 15 parts by weight of a carbon-functional silane as at least a part of the crosslinking agent. Further, (C) the titanium chelate compound as a curing catalyst may have alkylacetyl acetate as a ligand.
[0023]
The method for preparing the room-temperature-curable polyorganosiloxane composition of the present invention includes the steps of: preparing a room-temperature-curable polyorganosiloxane composition containing the following components (A) to (D) as essential components before mixing and kneading. It is characterized in that the component (D) is added to the component (A) or the component (D) is added during mixing and kneading of the components (A) and (B).
(A) (A1) a silicon-functional polydiorganosiloxane having an average of more than two hydrolyzable groups as silicon functional groups in the molecule, and / or (A2) two or more silicon functional groups in the molecule. 100 parts by weight of a polyorganosiloxane comprising a silicon-functional polydiorganosiloxane and a crosslinker
(B) Specific surface area 20 to 800 m²/ G of silica powder 1.0 to 200 parts by weight
(C) 0.5 to 15 parts by weight of a titanium chelate compound as a curing catalyst
(D) 0.01 to 3.0% by weight of a titanium ester compound which is a surface treatment agent and a surface treatment accelerator of the silica powder (however, the ratio to the (B) silica powder).
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described.
[0025]
Embodiments of the room temperature curable polyorganosiloxane composition of the present invention include (A) (A1) a silicon-functional polydiorganosiloxane having on average more than two hydrolyzable groups as silicon functional groups in the molecule; and And / or (A2) a polyorganosiloxane comprising a silicon-functional polydiorganosiloxane having two or more silicon functional groups in the molecule and a crosslinking agent, and based on 100 parts by weight of the polyorganosiloxane as the component (A). , (B) specific surface area 20 to 800 m²/ G of silica powder in an amount of 1.0 to 200 parts by weight, and (C) 0.5 to 15 parts by weight of a titanium chelate compound as a curing catalyst. As the component (D), a surface treatment agent for the silica powder as the component (B) and a titanium ester compound as a surface treatment accelerator are used in an amount of 0.01 to 3.0% by weight based on the silica powder (B). Contains in proportions.
[0026]
In the present invention, the polyorganosiloxane (A) used as the base polymer comprises a combination of the component (A1) and / or the component (A2) having a silicon functional group and a crosslinking agent, and the component (A1) is Itself causes a crosslinking reaction by the catalytic action of the component (C) to be cured. In addition, the combination of the component (A2) and the crosslinking agent is cured by causing a crosslinking reaction between the component (A2) and the crosslinking agent due to the catalytic action of the component (C). In each case, the reaction is a hydrolysis reaction followed by a condensation reaction, and the reaction proceeds in the presence of moisture in the air.
[0027]
In the embodiment of the present invention, the surface treatment of the silica powder is performed by using (D) a surface treatment agent and a titanium ester compound as a surface treatment accelerator. The use of the component (A1) is preferred.
[0028]
The components (A1) and (A2), which are the components (A) used in the embodiment of the present invention, are typically represented by the following general formula:
Embedded image

Is a substantially linear polyorganosiloxane represented by
[0029]
Where R¹Represents a substituted or unsubstituted monovalent hydrocarbon group which may be the same or different from each other;²Is -ZSiR³ _3-pX_pRepresents Here, Z represents oxygen and / or a divalent hydrocarbon group;³Represents a substituted or unsubstituted monovalent hydrocarbon group which may be the same or different, X represents an alkoxy group which is a hydrolyzable group, and p is a number of 1 to 3. N is a number that makes the viscosity of the component (A) at 23 ° C. 20 to 1,000,000 mPa · s. Terminal group R²Is a silicon-functional siloxy unit having at least one hydrolyzable group X which is a silicon functional group, and the component (A1) and the component (A2) have the above-mentioned hydrolyzable group X at both ends of the molecule. At least one.
[0030]
R¹Is a substituted or unsubstituted monovalent hydrocarbon group which may be the same or different from each other. R¹As alkyl groups such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, octyl group, decyl group and dodecyl group; alkenyl groups such as vinyl group and aryl group; phenyl group and tolyl And aryl groups such as xylyl groups; aralkyl groups such as 2-phenylethyl group and 2-phenylpropyl group; and further, some of the hydrogen atoms of these hydrocarbon groups are substituted with other atoms or groups. A substituted hydrocarbon group such as a halogenated alkyl group such as a chloromethyl group, a 3-chloropropyl group or a 3,3,3-trifluoropropyl group; a cyanoalkyl group such as a 3-cyanopropyl group. Is exemplified. It is easy to synthesize, and the component (A) has a low viscosity for its molecular weight, giving good extrudability to the composition before curing, and giving good physical properties to the composition after curing. For this reason, it is preferable that 85% or more of all the organic groups are methyl groups, and it is more preferable that substantially all the organic groups are methyl groups.
[0031]
On the other hand, especially when heat resistance, radiation resistance, cold resistance or transparency is imparted to the composition, R¹When imparting oil resistance and solvent resistance to a required amount of phenyl group as a part of¹When a 3,3,3-trifluoropropyl group or a 3-cyanopropyl group is given as a part of¹Can be arbitrarily selected depending on the purpose, for example, using a long-chain alkyl group or an aralkyl group together with a methyl group.
[0032]
Terminal group R²In which R is bonded to a silicon atom³May be the same or different from each other, and R¹A substituted or unsubstituted monovalent hydrocarbon group which may be the same or different from¹Are the same as those described above. A methyl group or a vinyl group is preferred because synthesis is easy and the reactivity of the hydrolyzable group X is excellent. Z may be the same or different, and examples thereof include an oxygen atom and an alkylene group such as a methylene group, an ethylene group and a trimethylene group; and a divalent hydrocarbon group such as a phenylene group. An oxygen atom and an ethylene group are preferred because of easy synthesis, and an oxygen atom is particularly preferred.
[0033]
X represents a terminal group R²At least one silicon functional group, that is, an alkoxy group which is a hydrolyzable group. Examples of such X include an alkoxy group such as a methoxy group, an ethoxy group, a propoxy group and a butoxy group; a substituted alkoxy group such as a 2-methoxyethoxy group and a 2-ethoxyethoxy group; an enoxy group such as an isopropenoxy group. And may be the same or different from each other. It is used for a wide range of applications, including ease of synthesis, physical properties of the composition before curing, stability during storage, curability, economical efficiency, and corrosion resistance in electric and electronic component applications. Is preferred.
[0034]
Terminal group R²The number p of the silicon functional group X in is preferably 1 to 3.
[0035]
The component (A) (that is, the component (A1) or the component (A2)) is used to impart appropriate extrudability to the composition before curing and to impart excellent mechanical properties to the rubber-like elastic body after curing. ) Is selected such that the viscosity of the component (A) at 23 ° C is in the range of 20 to 1,000,000 mPa · s. When the viscosity of the component (A) is less than 20 mPa · s, the elongation of the rubber-like elastic body after curing is not sufficient. On the other hand, when it exceeds 1,000,000 mPa · s, it is difficult to obtain a uniform composition, and the extrusion workability is poor. descend. Particularly desirable viscosity is in the range of 500 to 200,000 mPa · s, because the properties required for the composition before and after curing are obtained in a well-balanced manner.
[0036]
In a room-temperature-curable polyorganosiloxane composition of the type that cures without using a crosslinking agent, X in the component (A), ie, the component (A1), serves as a crosslinking means, and the crosslinking reaction proceeds even without a crosslinking agent. Hardens to form a rubber-like elastic body. Preferable examples of X include an alkoxy group such as a methoxy group; an acyloxy group such as an acetoxy group; and a methylethylketoximato group. An alkoxy group is preferable from the viewpoint of corrosion resistance. By using such a component (A1) as a base polymer, the composition before curing is stabilized and excellent curability is obtained.
[0037]
In a room-temperature-curable polyorganosiloxane composition of the type cured using a crosslinking agent, a crosslinked structure is formed by using the component (A2) in combination with a crosslinking agent. As the component (A2), those in which X is a hydroxyl group or p is 1 (that is, a compound having a hydroxyl group and / or two Xs which are hydrolyzable groups similar to the above in the molecule) may be used. it can.
[0038]
Examples of the crosslinking agent used in combination with the component (A2) include a silicone for reacting with the silicon functional group X in the component (A2) in the presence of water and a curing catalyst to cure the composition. A silicon compound having a functional group and / or a partially hydrolyzed condensate thereof are used.
[0039]
This crosslinking agent has the general formula: R⁴ _4-qSiY_q
(Where R⁴Represents a substituted or unsubstituted monovalent hydrocarbon group which may be the same or different from each other, and Y represents a hydrolyzable group. In addition, q is a number exceeding 2 on average and 4 or less. ).
[0040]
R⁴The organic group R directly bonded to the silicon atom of the component (A)¹The same groups can be exemplified. A methyl group or a vinyl group is preferred because of its availability and an excellent crosslinking reaction rate. Examples of the hydrolysis-reactive group Y are the same as those exemplified as X present in the terminal group of the component (A).
[0041]
Examples of such crosslinking agents include tetramethoxysilane, methyltrimethoxysilane, vinyltrimethoxysilane, phenyltrimethoxysilane, tetraethoxysilane, methyltriethoxysilane, vinyltriethoxysilane, phenyltriethoxysilane, tetrapropoxy Alkoxy group-containing compounds such as silane, tetraisopropoxysilane and partial hydrolysis condensates thereof; tetrakis (2-ethoxyethoxy) silane, methyltris (2-methoxyethoxy) silane, vinyl (2-ethoxyethoxy) silane, phenyl Substituted alkoxy group-containing compounds such as tris (2-methoxyethoxy) silane and partially hydrolyzed condensates thereof; methyltriisopropenoxysilane, vinyltriisopropenoxysilane, phenyltrii Propenoxyethyl silane, dimethyl isopropenoxysilane silane, such as an enoxy group-containing compounds such as methyl vinyl di- isopropenoxysilane silane and their partially hydrolyzed condensates are exemplified. When the component (A) is only the silane having q of 2 (A2), the crosslinked structure is not formed only by extending the chain length, and a cured rubber product cannot be produced. Therefore, instead of using only the silane in which q is 2, it is used in combination with the silane in which q is 3 or 4. This is not the case when the component (A) is (A1) and has three or more hydrolyzable groups X of the above general formula [Chemical Formula 1] in one molecule.
[0042]
Considering that the synthesis is easy and the storage stability of the composition is not impaired, and that a high crosslinking reaction rate, that is, a high curing rate is given, among these silane compounds, tetramethoxysilane, tetraethoxysilane, methyl It is preferable to use trimethoxysilane, vinyltrimethoxysilane, methyltris (isopropenoxy) silane, vinyltris (isopropenoxy) silane, and partially hydrolyzed condensates thereof.
[0043]
In the case where the component (A) X is a hydrolyzable group and p exceeds 1 on average, the component (A1) can be cured without a crosslinking agent as described above. However, even in such a case, it is preferable to use the above-mentioned crosslinking agent in combination in order to achieve a good balance between the curability of the composition and the mechanical properties of the rubber-like elastic material obtained by curing. Further, it is more preferable to use a crosslinking agent in which the hydrolyzable group Y is the same as X.
[0044]
The amount of the crosslinking agent to be added is generally 0.1 to 15 parts by weight, preferably 0.3 to 10 parts by weight, per 100 parts by weight of the component (A). If the amount is less than 0.1 part by weight, crosslinking is not sufficiently performed, and not only a cured product having low hardness is obtained, but also the storage stability of the composition containing the crosslinking agent is deteriorated. On the other hand, if the amount is more than 15 parts by weight, it is not economically meaningless, and the balance between the curability of the composition and the mechanical properties after curing is remarkably reduced.
[0045]
In the present invention, as described in the specific examples above, R⁴In addition to the silicon-functional compound having a monovalent hydrocarbon group, a similar carbon-functional compound having a substituted monovalent hydrocarbon group may be used as part or all of the crosslinking agent. Such R⁴Examples thereof include a substituted amino group, epoxy group, isocyanato group, (meth) acryloxy group, mercapto group, or alkyl group or phenyl group substituted with a halogen atom. Examples of the substituted alkyl group include a substituted methyl group, a 3-substituted propyl group, and a 4-substituted butyl group, and a 3-substituted propyl group is preferable because of easy synthesis.
[0046]
Such R⁴Examples of the compound having the following formula: 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltriisopropoxysilane, 3-aminopropyltriacetamidosilane, N- (2-aminoethyl) -3- Aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltriethoxysilane, N-methyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N, N Substituted or unsubstituted amino group-containing silanes such as dimethyl-3-aminopropyltrimethoxysilane; 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3,4-epoxycyclohexylethyl Trimethoxysilane Isocyanato group-containing silanes such as 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropylmethyldimethoxysilane and 3-isocyanatopropyltriethoxysilane; 3-acryloxypropyltrimethoxysilane; (Meth) acryloxy group-containing silanes such as methacryloxypropyltrimethoxysilane, 3-acryloxypropylmethyldimethoxysilane and 3-methacryloxypropylmethyldimethoxysilane; mercapto group-containing silanes such as 3-mercaptopropyltrimethoxysilane And halogen-containing silanes such as 3-chloropropyltrimethoxysilane.
[0047]
Further, tris (N-trimethoxypropyl) isocyanurate, tris (N-triethoxypropyl) isocyanurate, and tris (N-methyldimethoxy) in which the isocyanato group of the above-mentioned isocyanato group-containing silane forms a cyclo ring (triazine-trione). Propyl) isocyanurate is likewise used as an adhesion-improving component.
[0048]
Such substituted hydrocarbon group-containing silanes and the above-mentioned vinyl group-containing silanes are carbon-functional silanes, and by blending them, improve the adhesion to various substrates when the composition is cured. be able to. The compounding of the carbon-functional silane is possible as long as the curability, the storage stability and the physical properties of the composition are not impaired, but the compounding of a large amount of the aminoalkyl group-containing silane and the mercapto group-containing silane is as follows: ) Poisons the titanium chelate compound as a component and significantly lowers its catalytic function, which is not preferable in terms of storage stability.
[0049]
The blending amount of the carbon-functional silane is preferably 0.05 to 15 parts by weight, more preferably 0.1 to 10 parts by weight, based on 100 parts by weight of the component (A). If the amount is less than 0.05 part by weight, the effect of improving the adhesiveness is small, and its expression is slow. Further, if the amount is more than 15 parts by weight, in addition to the above-mentioned problems, storage stability and workability deteriorate, and a yellowing phenomenon occurs, which is not preferable.
[0050]
In the present invention, the silica powder as the component (B) is a reinforcing material when the polyorganosiloxane composition is cured into a rubber state or a gel state, and is 20 to 800 m²/ G specific surface area. Specific surface area of silica powder is 20m²/ G, the reinforcing property is insufficient. The specific surface area is 800m²/ G is not suitable for the composition of the present invention because the cohesion between the powders is too large. Among these silica powders, from the viewpoint of mechanical strength, 50 m²/ G or more is preferable, and from the viewpoints of production and availability, 500 m²/ G of silica powder having a specific surface area of not more than / g is preferred.
[0051]
Examples of such silica powder include fumed silica, wet silica, and fused silica, and one or more of these may be used in combination. The compounding amount of the silica powder as the component (B) is 1.0 to 200 parts by weight, more preferably 3.0 to 50 parts by weight, per 100 parts by weight of the component (A). If the amount of the silica powder is less than 1.0 part by weight, the mechanical strength of the obtained cured product is insufficient, and if it exceeds 200 parts by weight, mixing is difficult and a uniform composition cannot be obtained. Such silica powder can be used regardless of whether it has been treated or not, but in the present invention, among those treated with a trimethylsilyl group, those having a high treatment degree may have a low effect.
[0052]
In the present invention, the titanium chelate compound which is the curing catalyst of the component (C) may have a structure in which X of the hydrolyzable groups contained as a crosslinking means of the component (A) itself and / or the hydrolyzable group X of the component (A) are used. And a hydrolyzable group Y of a cross-linking agent are reacted in the presence of moisture to form a cross-linked structure, and are a curing catalyst for obtaining a rubber-like elastic body. It is preferable to use a titanium chelate compound having alkylacetyl acetate as a ligand.
[0053]
Such components (C) include diisopropoxytitanium bis (methylacetyl acetate), diisopropoxytitanium bis (ethylacetylacetate), diisopropoxytitanium bis (butylacetylacetate), dibutoxytitanium bis (methylacetylacetate), Butoxy titanium bis (ethyl acetyl acetate), diisopropoxy titanium bis (butyl acetyl acetate), diisopropoxy titanium bis (2-ethylhexyl acetyl acetate), diisopropoxy titanium bis (2-ethylhexyl acetyl acetate), diisopropoxy titanium bis (2-ethyl hexyl) Acetylacetate), dibutoxytitanium bis (2-ethylhexyl acetylacetate), dibutoxytitanium bis (2-ethylhexylacetyl) Acetate), diisopropoxy titanium bis (2-ethylhexyl acetyl acetate), diisopropoxy titanium bis (acetyl acetate), diisopropoxy titanium bis (acetyl acetate), diisopropoxy titanium bis (acetyl acetate), dibutoxy titanium bis (acetyl acetate), Titanium chelate compounds such as dibutoxytitanium bis (acetyl acetate) and diisopropoxy titanium bis (acetyl acetate) are exemplified.
[0054]
Among the above compounds, diisopropoxytitanium bis (methylacetyl acetate), diisopropoxytitanium bis (ethylacetylacetate), diisopropoxytitanium bis (butylacetylacetate) among the above-mentioned compounds because of their corrosion resistance, curing acceleration and availability. And diisopropoxytitanium bis (2-ethylhexylacetyl acetate).
[0055]
The compounding amount of the component (C) is 0.5 to 15 parts by weight, more preferably 1.0 to 10 parts by weight, per 100 parts by weight of the component (A). If the amount is less than 0.5 part by weight, it does not act sufficiently as a curing catalyst, and it takes a long time to cure. In addition, the curing in the deep part of the rubber layer far from the contact surface with air becomes insufficient, and on the contrary, 15 parts by weight If the amount is more than one part, there is no effect corresponding to the compounding amount and it is not only meaningless, but also economically disadvantageous, which is not preferable.
[0056]
The titanium ester compound as the surface treatment agent and the surface treatment accelerator of the component (D) of the present invention is used as a surface treatment agent for silica powder and for promoting surface mixing for facilitating the mixing of the component (A) with the silica powder. It has an action as an agent. The silanol group on the surface of the silica powder is not only treated by the alkoxy group, which is the reactive group in the component (D), but also the reactive group in the component (A) is converted into the silica by the reactive group in the component (D). By appropriately promoting the reaction with the silanol on the surface of the powder, the silanol group on the surface of the silica powder is also treated by the component (A).
[0057]
Thus, fluidity is imparted to the composition, and the extrusion force can be reduced. In addition, by treating the silanol groups on the surface of the silica powder, a composition having excellent storage stability can be obtained without causing deterioration in curability or thickening over time.
[0058]
As such a titanium ester compound, carboxylic acid esters such as isopropyl trioctanoyl titanate, isopropyl dimethacryl isosteroyl titanate, isopropyl diacryl isostearyl titanate, diisostearoyl ethylene titanate, isopropyl triisostearoyl titanate, isopropyl tridodecyl benzene Sulfonate such as sulfonyl titanate, phosphate such as isopropyl tris (dioctyl borophosphate) titanate, bis (dioctyl borophosphate) oxyacetate titanate, bis (dioctyl borophosphate) ethylene titanate, isopropyl tri (dioctyl phosphate) titanate , Tetraisopropylbis (dioctylphosphine) Site) titanate, tetraoctylbis (ditridecylphosphite) phosphite such as titanates are exemplified. Carboxylic acid esters, phosphoric acid esters, and phosphites are preferred from the viewpoint of the effect of the surface treatment, ease of handling and availability. From the viewpoint of corrosion resistance, use of a carboxylic acid ester is more preferable. Further, the number of carbon atoms in the carboxylic acid moiety is preferably 20 or less from the viewpoint of the effect of the surface treatment and the compatibility in the obtained composition, and more preferably 4 or more from the viewpoint of corrosion resistance.
[0059]
(D) The amount of the titanium ester compound is 0.01 to 3.0% by weight based on the silica powder as the component (B). It is preferably at least 0.05% by weight from the viewpoint of the efficiency of surface treatment, and more preferably at most 2.0% by weight from the viewpoint of storage stability of the obtained base compound.
[0060]
The room-temperature-curable polyorganosiloxane composition of the present invention imparts an appropriate fluidity to the composition before curing, and gives a rubber-like elastic body obtained by curing, for example, a sealing material, an adhesive, an in-situ molded gasket, and the like. In order to provide the high mechanical strength required when used as a filler, a filler generally used can be blended in addition to the silica powder as the component (B).
[0061]
Such fillers include precipitated silica, reinforcing fillers such as fumed titanium oxide, diatomaceous earth, ground silica, aluminosilicate, zinc oxide, aluminum oxide, calcium carbonate, organic acid surface-treated calcium carbonate, and carbonic acid. Non-reinforcing fillers such as magnesium, calcium silicate, talc and ferric oxide are exemplified, and are selected according to the physical properties required of the rubber-like elastic body after curing. The surface of these fillers may be surface-treated with organochlorosilanes, polyorganosiloxanes, hexamethyldisilazane, or the like. It is necessary to remove by-products produced by the reaction of the surface treating agent from the composition. If these surface treatment agents and their by-products are present in the composition, the object of the present application, in which there is little change in viscosity and physical properties during long-term storage, may not be achieved.
[0062]
Further, for example, when transparency is required, it is preferable to use fumed silica, and as a building sealing material, particularly when a low modulus is required, it is preferable to use a non-reinforcing filler. . Among the above fillers, if the amount of the reinforcing filler is too small, the effect of improving the mechanical properties hardly appears, and if it is too large, the modulus becomes too large and the elongation at break is increased. Become smaller. The amount of the filler other than the silica powder is preferably 1 to 200 parts by weight, more preferably 5 to 100 parts by weight, per 100 parts by weight of the component (A).
[0063]
Further, according to the purpose of the composition of the present invention, a pigment, a thixotropic agent, a viscosity modifier for improving extrusion workability, an ultraviolet absorber, a fungicide, a heat resistance improver, a flame retardant Various additives such as an agent may be added.
[0064]
The composition of the present invention can be obtained by mixing all of the above components and, if necessary, various additives in a state where moisture is blocked. The order of addition of the titanium ester compound as the component (D) is such that the silica powder can be uniformly dispersed in the system and the surface of the silica powder can be sufficiently uniformly treated, and the cured product is formed by a curing catalyst. In order to reduce the influence on the component (C), before the component (C) is mixed, the component (D) is first added to the component (A) before mixing and kneading, or the component (A) and the component (B) are mixed. It is desirable to add the component (D) at the time of mixing and kneading.
[0065]
The resulting composition can be used as a so-called one-package room temperature curable composition that is stored as it is in a closed container and cured only when exposed to moisture in the air at the time of use. Further, the composition of the present invention is prepared, for example, as a composition in which a cross-linking agent and a curing catalyst are separated, and is appropriately divided and stored in two to three separate containers, and these are mixed at the time of use, so-called multi-package type. It can also be used as a room temperature curable composition.
[0066]
The room-temperature-curable polyorganosiloxane composition obtained according to the present invention is stable under sealed conditions free from moisture, and cures at room temperature upon contact with moisture in the air to produce a rubber-like elastic body. In particular, the present invention provides a room-temperature-curable polyorganosiloxane that has better curability than conventional products and has excellent storage stability.
[0067]
Hereinafter, the present invention will be described specifically with reference to examples, but the present invention is not limited to the examples. In Examples, “parts” means “parts by weight”, and all physical property values such as viscosity are values at 23 ° C. and 50% relative humidity.
[0068]
Example 1
To 100 parts of α, ω-bis (methyldimethoxysiloxy) polydimethylsiloxane having a viscosity of 1,000 mPa · s, 0.14 parts of isopropyl triisostearoyl titanate which is a surface treating agent for silica powder is added, and the mixture is uniformly mixed at room temperature for 15 minutes. After mixing, the specific surface area is 150m²/ G of fumed silica in an all-purpose mixer, and kneaded uniformly at room temperature for 1 hour. Next, the mixture was kneaded under heating and reduced pressure at 80 to 100 ° C. for 30 minutes to obtain a uniform base compound B-1. Next, 3.0 parts of methyltrimethoxysilane, 0.5 part of tris (N-trimethoxypropyl) isocyanurate and diisopropoxytitanium bis (ethylacetyl acetate) were added to 114 parts of the obtained base compound B-1. 5 parts were added and mixed homogeneously while keeping moisture out, to obtain a polyorganosiloxane composition 1.
[0069]
Example 2
To 100 parts of α, ω-bis (methyldimethoxysiloxy) polydimethylsiloxane having a viscosity of 1,000 mPa · s, 0.14 parts of tetraisopropylbis (dioctylphosphite) titanate which is a surface treating agent for silica powder is added, and the mixture is added at room temperature. After 15 minutes of uniform mixing, the specific surface area is 150m²/ G of fumed silica in an all-purpose mixer, and kneaded uniformly at room temperature for 1 hour. Next, the mixture was kneaded under heating and reduced pressure at 80 to 100 ° C. for 30 minutes to obtain a uniform base compound B-2. Then, in 114 parts of the obtained base compound B-2, 3.0 parts of methyltrimethoxysilane, 0.5 part of tris (N-trimethoxypropyl) isocyanurate and 0.5 parts of diisopropoxytitanium bis (ethylacetyl acetate) 2. 5 parts were added, and the mixture was uniformly mixed under the exclusion of moisture to obtain a polyorganosiloxane composition 2.
[0070]
Example 3
0.15 parts of tetraisopropylbis (dioctylphosphite) titanate is added to 100 parts of α, ω-bis (methyldimethoxysiloxy) polydimethylsiloxane having a viscosity of 20,000 mPa · s, and the mixture is uniformly mixed at room temperature for 15 minutes. Specific surface area is 200m²/ G of fumed silica of 15 g / g were charged into a universal mixer and kneaded uniformly at room temperature for 1 hour. Next, kneading was performed under heating and reduced pressure at 80 to 100 ° C. for 30 minutes to obtain a uniform base compound B-3. Then, in 115 parts of the obtained base compound B-3, 2.0 parts of methyltrimethoxysilane, 0.5 part of tris (N-trimethoxypropyl) isocyanurate and diisopropoxytitanium bis (ethylacetylacetate) 2. 0 parts were added, and the mixture was uniformly mixed under the exclusion of moisture to obtain a polyorganosiloxane composition 3.
[0071]
Example 4
0.15 parts of tetraisopropylbis (dioctylphosphite) titanate is added to 100 parts of α, ω-bis (methyldimethoxysiloxy) polydimethylsiloxane having a viscosity of 20,000 mPa · s, and the mixture is uniformly mixed at room temperature for 15 minutes. Specific surface area is 200m²/ G of octamethylcyclotetrasiloxane treated with 15 parts of fumed silica were charged into a universal mixer and kneaded uniformly at room temperature for 1 hour. Next, the mixture was kneaded under heating and reduced pressure at 80 to 100 ° C. for 45 minutes to obtain a uniform base compound B-4. Then, in 115 parts of the obtained base compound B-4, 2.0 parts of methyltrimethoxysilane, 0.5 part of tris (N-trimethoxypropyl) isocyanurate and diisopropoxytitanium bis (ethylacetyl acetate) 2. 0 parts were added, and the mixture was uniformly mixed under the exclusion of moisture to obtain a polyorganosiloxane composition 4.
[0072]
Example 5
Base compound B-5 was obtained in the same manner as in Example 4, except that isopropyl triisostearoyl titanate was used instead of tetraisopropyl bis (dioctyl phosphite) titanate as a surface treatment agent for the silica powder. Then, in 115 parts of the obtained base compound B-5, 2.0 parts of methyltrimethoxysilane, 0.5 parts of tris (N-trimethoxypropyl) isocyanurate and diisopropoxytitanium bis (ethylacetyl acetate) 2. 0 parts were added, and the mixture was uniformly mixed under the exclusion of moisture to obtain a polyorganosiloxane composition 5.
[0073]
Comparative Example 1
A specific surface area of 150 m is added to 100 parts of α, ω-bis (methyldimethoxysiloxy) polydimethylsiloxane having a viscosity of 1,000 mPa · s.²/ G of fumed silica was charged into a universal mixer, mixed uniformly at room temperature for 15 minutes, and further kneaded uniformly at room temperature for 1 hour. Next, kneading was performed under heating and reduced pressure at 80 to 100 ° C. for 30 minutes to obtain a uniform base compound C-1. Then, in 114 parts of the obtained base compound C-1, 3.0 parts of methyltrimethoxysilane, 0.5 part of tris (N-trimethoxypropyl) isocyanurate and diisopropoxytitanium bis (ethylacetyl acetate) 2. Five parts were added, and the mixture was uniformly mixed under the exclusion of moisture to obtain Comparative Composition 1.
[0074]
Comparative Example 2
To 100 parts of α, ω-bis (methyldimethoxysiloxy) polydimethylsiloxane having a viscosity of 1,000 mPa · s, add 0.14 parts of tetrabutoxytitanium, which is a conventional surface treatment agent for silica powder, and uniformly mix at room temperature for 15 minutes. After mixing, the specific surface area is 150m²/ G of fumed silica in an all-purpose mixer, and kneaded uniformly at room temperature for 1 hour. Next, the mixture was kneaded under heating and reduced pressure at 80 to 100 ° C. for 30 minutes to obtain a uniform base compound C-2. Then, in 114 parts of the obtained base compound C-2, 3.0 parts of methyltrimethoxysilane, 0.5 part of tris (N-trimethoxypropyl) isocyanurate and diisopropoxytitanium bis (ethylacetyl acetate) 2. 5 parts were further added, and the mixture was uniformly mixed under the exclusion of moisture to obtain Comparative Composition 2.
[0075]
Comparative Example 3
A uniform base compound C-3 was obtained in the same manner as in Comparative Example 2, except that 0.14 parts of diisopropoxytitanium bis (ethyl acetylacetate) was used instead of tetrabutoxytitanium. Then, in 114 parts of the obtained base compound C-3, 3.0 parts of methyltrimethoxysilane, 0.5 part of tris (N-trimethoxypropyl) isocyanurate and diisopropoxytitanium bis (ethylacetylacetate) 2. Five parts were added, and the mixture was uniformly mixed under the exclusion of moisture to obtain Comparative Composition 3.
[0076]
Comparative Example 4
A uniform base compound C-4 was obtained in the same manner as in Comparative Example 2, except that 0.2 parts of 3-aminopropyltriethoxysilane was used instead of tetrabutoxytitanium. Then, in 114 parts of the obtained base compound C-4, 3.0 parts of methyltrimethoxysilane, 0.5 part of tris (N-trimethoxypropyl) isocyanurate and diisopropoxytitanium bis (ethylacetylacetate) 2. 5 parts were added, and the mixture was uniformly mixed under the exclusion of moisture to obtain Comparative Composition 4.
[0077]
Comparative Example 5
A base compound C-5 was obtained in the same manner as in Example 4, except that the titanium ester compound as the surface treating agent was not used. Next, 2.0 parts of methyltrimethoxysilane, 0.5 part of tris (N-trimethoxypropyl) isocyanurate and diisopropoxytitanium bis (ethylacetyl acetate) were added to 115 parts of the obtained base compound C-5. 0 parts were added, and the mixture was homogeneously mixed under the exclusion of moisture to obtain Comparative Composition 5.
[0078]
Next, for the polyorganosiloxane compositions prepared and sealed and stored in Examples 1 to 5 and Comparative Examples 1 to 5, the dry time to touch, physical properties, storage stability, and adhesiveness were measured in Examples 1 to 5. 3 and Comparative Examples 1 to 4 were measured for viscosity, and Examples 4 to 5 and Comparative Example 5 were measured for extrusion force.
[0079]
In addition, for the base compounds obtained in Examples 1 to 3 and Comparative Examples 1 to 4, the appearance, the yield, the viscosity and the viscosity after aging were examined, and for the composition obtained using the base compound after aging, Appearance, viscosity and dry time to touch and physical properties were measured.
[0080]
The measurement of the dry time to touch, physical properties, storage stability, adhesiveness, and extrusion force were performed as described below.
[0081]
(A) Drying time to the touch: After extruding the composition in an atmosphere of 23 ° C. and 50% RH, the time required to confirm that the composition was in a dry state by contacting the surface with a finger was measured.
[0082]
(B) Physical properties: The composition was extruded into a sheet having a thickness of 2 mm, and the obtained sheet was left at 23 ° C. and 50% RH for 168 hours to be cured by moisture in the air. Was measured according to JIS K6301.
[0083]
(C) Storage stability: The composition was placed in a container protected from moisture, heated at 70 ° C. for 5 days, and then the touch dry time and viscosity were measured in an atmosphere of 23 ° C. and 50% RH. Also, the sheet was extruded into a sheet having a thickness of 2 mm, left at 223 ° C. and 50% RH for 168 hours, and was cured by the moisture in the air. It was measured.
[0084]
(D) Adhesion: Tensile shear strength and cohesive failure rate were measured according to JIS K 6301 using aluminum, glass, polycarbonate, and phenolic resin as adherends.
[0085]
(E) Extrusion force: A commercially available 333 ML cartridge was used, with the nozzle tip adjusted to an inner diameter of 6.2 mm, and the force for extruding the plunger at the bottom of the cartridge was measured by an autograph.
[0086]
Tables 1 and 2 show the measurement results.
[0087]
[Table 1]

[0088]
[Table 2]

[0089]
As can be seen from Tables 1 and 2, the polyorganosiloxane compositions prepared in Examples 1 to 5 have excellent storage stability, are stable under sealed conditions free from moisture, and have a high moisture content in the air. Cured at room temperature only upon contact with In addition, a rubber-like elastic body having good adhesiveness and excellent physical properties can be obtained without a decrease in curability due to storage.
[0090]
【The invention's effect】
As is clear from the above description, the room-temperature-curable polyorganosiloxane composition of the present invention is stable under sealed conditions in the absence of moisture, cures at room temperature by contact with moisture in the air, A rubber-like elastic body having good mechanical properties and excellent adhesion durability is produced. In addition, it has excellent storage stability, and its curability does not decrease even after long-term storage. Therefore, it is suitable as a sealing material, an adhesive, an in-situ molded gasket, and the like.

Claims (4)

(A) (A1) a silicon-functional polydiorganosiloxane having an average of more than two hydrolyzable groups as silicon functional groups in the molecule, and / or (A2) two or more silicon functional groups in the molecule. A room temperature curable polyorganosiloxane composition comprising a polyorganosiloxane comprising a silicon-functional polydiorganosiloxane having
With respect to 100 parts by weight of the polyorganosiloxane (A),
(B) 1.0 to 200 parts by weight of silica powder having a specific surface area of 20 to 800 m ² / g;
(C) a titanium catalyst compound containing 0.5 to 15 parts by weight of a titanium chelate compound as a curing catalyst and (D) a titanium ester compound as a surface treatment agent and a surface treatment accelerator for the silica powder, Room temperature-curable polyorganosiloxane composition, characterized in that it is contained in an amount of 0.01 to 3.0% by weight. The room temperature curable polyorganosiloxane composition according to claim 1, wherein the crosslinker contains 0.05 to 15 parts by weight of a carbon-functional silane as at least a part of the crosslinker. The room temperature curable polyorganosiloxane composition according to claim 1 or 2, wherein the (C) titanium chelate compound as a curing catalyst has alkylacetyl acetate as a ligand. In preparing a room-temperature-curable polyorganosiloxane composition containing the following components (A) to (D) as essential components, component (D) is added to component (A) before mixing and kneading, or ( A method for preparing a room-temperature-curable polyorganosiloxane composition, wherein the component (D) is added during mixing and kneading of the components (A) and (B).
(A) (A1) a silicon-functional polydiorganosiloxane having an average of more than two hydrolyzable groups as silicon functional groups in the molecule, and / or (A2) two or more silicon functional groups in the molecule. 100 parts by weight of a polyorganosiloxane comprising a silicon-functional polydiorganosiloxane and a crosslinking agent (B) 1.0 to 200 parts by weight of silica powder having a specific surface area of 20 to 800 m ² / g (C) Titanium chelate compound as a curing catalyst 0.5 to 15 parts by weight (D) 0.01 to 3.0% by weight of a titanium ester compound which is a surface treatment agent and a surface treatment accelerator of the silica powder (however, the ratio to the (B) silica powder).