JP4083887B2 - Heat-curable foamable organopolysiloxane composition and method for curing the same - Google Patents

Description

【０００７】
（式中、R¹およびＸは、各々炭素数１〜８のアルキル基、炭素数６〜１０のアリール基、炭素数７〜１０のアラルキル基、炭素数２〜８のアルケニル基、水酸基、およびこれらの基の炭素原子に結合した水素原子の少なくとも一部をハロゲン原子で置換した基よりなる群から選ばれるが、全R¹基とＸ基との合計のうち、少なくとも一つはアルケニル基または水酸基である。またｐは、25℃での粘度が100〜100,000cStとなるような正の整数である。）
で表され、且つ１分子中にアルケニル基、水酸基またはそれらの混合基を、分子中の全R¹基とＸ基との合計に対して0.01〜５mol％含有するオルガノポリシロキサン、
（Ｂ）珪素原子に結合した水素原子を有するオルガノハイドロジェン珪素化合物として、下記一般式 (2) で表されかつ１分子中に珪素原子に結合した水素原子を少なくとも２個有するオルガノハイドロジェンシロキサンのみ：上記（Ａ）成分１００重量部当り１〜５０重量部、
一般式(2)：
【０００８】
【化４】

【０００９】
（式中、R²は炭素数１〜８のアルキル基、炭素数６〜１０のアリール基、炭素数７〜１０のアラルキル基、およびこれらの基の炭素原子に結合した水素原子の少なくとも一部をハロゲン原子で置換した基よりなる群から選ばれ、Ｙは炭素数１〜８のアルキル基、炭素数６〜１０のアリール基、炭素数７〜１０のアラルキル基、これらの基の炭素原子に結合した水素原子の少なくとも一部をハロゲン原子で置換した基、および水素原子よりなる群から選ばれ、但し、Ｙの合計のうち少なくとも１０モル％は水素原子である。またｍ，ｎは各々１≦ｍ＋ｎ≦500を満足する０または正の整数である。）
（Ｃ）水、１価〜３価の（Ｅ）成分以外のアルコール、オルガノヒドロキシシラン、および珪素原子数２〜５０のヒドロキシ基含有オルガノシロキサンオリゴマーから成る群から選択される、単独または２種以上の、活性水素基を有する化合物：上記（Ａ）成分１００重量部当り０．１〜２０重量部、
（Ｄ）白金触媒： 本組成物中において白金原子として１〜１０００ｐｐｍ、および
（Ｅ）アセチレンアルコール系化合物： 上記（Ａ）成分１００重量部当り０．００１〜２０重量部
を含有してなる。
また本発明の硬化方法は、上記組成物を機械的に均一に混合後、40℃以上に加熱して発泡、硬化させることを特徴とするものである。
【００１０】
【発明の実施の形態】
以下に本発明組成物の各成分について説明する。
（Ａ）成分のオルガノポリシロキサン
（Ａ）成分はベースポリマーとして用いられ、前記一般式(1)で示される。
一般式(1)において、 R¹およびＸは、炭素数１〜８のアルキル基、炭素数６〜１０のアリール基、炭素数７〜１０のアラルキル基、炭素数２〜８のアルケニル基、水酸基およびこれらの基の炭素原子に結合した水素原子の少なくとも一部をハロゲン原子で置換した基よりなる群から選ばれ、全R¹基とＸ基との合計のうち、少なくとも一つはアルケニル基または水酸基であるが、好適には分子中に２個以上の、アルケニル基または水酸基を有するもの、特には少なくとも分子鎖両末端にそれぞれアルケニル基または水酸基を有するものが挙げられる。アルケニル基および水酸基以外のR¹およびＸは、各々、上記の群から選ばれた、単独の基でも或いは２種以上の基であってもよい。
【００１１】
一般式(1)におけるアルケニル基および水酸基は架橋反応に寄与する官能基で、アルケニル基、水酸基またはそれらの混合基は、分子鎖末端の珪素原子或いは分子鎖途中の珪素原子のいずれに結合したものであっても、或いは両方に結合したものであってもよいが、これらの基は分子中の全R¹基とＸ基との合計に対して0.01〜５mol％、好ましくは0.1〜３mol％含まれていなければならない。またｐは、25℃での粘度が100〜100,000cSt、好ましくは500〜50,000cStとなるような正の整数である。
【００１２】
炭素数１〜８のアルキル基としては、メチル、エチル、プロピル、イソプロピル、ブチル、イソブチル、ｔｅｒｔ−ブチル、ペンチル、ネオペンチル、ヘキシル、シクロヘキシル、ヘプチル、オクチル基が挙げられる。炭素数６〜１０のアリール基としては、フェニル、トリル、キシリル、エチルフェニル、ナフチル基等が挙げられる。炭素数７〜１０のアラルキル基としては、ベンジル、フェニルエチル、フェニルプロピル基等が挙げられる。炭素数２〜８のアルケニル基としては、ビニル、アリル、プロペニル、イソプロペニル、ブテニル、イソブテニル、ヘキセニル基等が挙げられる。また、これらの基の炭素原子に結合する水素原子の少なくとも一部をハロゲン原子で置換した基としては、3,3,3-トリフルオロプロピル、クロロメチル、ブロモエチル基等が挙げられる。
入手のし易さ、コストの点を考えると、Ｘとしてはビニル基または水酸基が好ましく、またR¹としてはメチル基、フェニル基または3,3,3-トリフルオロプロピル基が好ましい。
このような（Ａ）成分のオルガノポリシロキサンとしては、具体的には分子鎖両末端がビニルジメチルシロキシ基或いは分子鎖両末端がヒドロキシジメチルシロキシ基で封鎖され、主鎖のジオルガノシロキサン繰り返し単位中にアルケニル基および水酸基を含有しない、直鎖状のジメチルポリシロキサンなどの直鎖状ジオルガノポリシロキサンが挙げられる。
【００１３】
なお、（Ａ）成分には、発泡体の強度向上のために、R¹ ₃SiO_1/2（R¹は前記と同じ）およびSiO₂から基本的になるレジン、例えば(CH₃)₃SiO_1/2および(CH₂=CH)(CH₃)₂SiO_1/2とSiO₂とからなり、(CH₃)₃SiO_1/2および(CH₂=CH)(CH₃)₂SiO_1/2の合計量とSiO₂量との比（モル比）が０．６〜１．２である、トルエンに可溶のビニル基含有シリコーンレジン等を添加してもよい。
【００１４】
（Ｂ ) 成分のオルガノハイドロジェン珪素化合物
前記一般式(2) で表される（Ｂ）成分のオルガノハイドロジェン珪素化合物は、１分子中に珪素原子に結合した水素原子（即ちSiH基）を少なくとも２個、好ましくは３個以上含有するオルガノハイドロジェンポリシロキサンであり、（Ａ）成分と反応して架橋反応を起こすと共に、（Ｃ）成分と反応して脱水素反応を起こし、発泡させる架橋剤兼発泡剤として使用される。
【００１５】
一般式(2) において、R²は炭素数１〜８のアルキル基、炭素数６〜１０のアリール基、炭素数７〜１０のアラルキル基、およびこれらの基の炭素原子に結合した水素原子の少なくとも一部をハロゲン原子で置換した基よりなる群から選ばれ、また一般式(2)において、Ｙは炭素数１〜８のアルキル基、炭素数６〜１０のアリール基、炭素数７〜１０のアラルキル基、水素原子、およびこれらの基の炭素原子に結合した水素原子の少なくとも一部をハロゲン原子で置換した基よりなる群から選ばれる。（Ｂ）成分として一般式(2)のオルガノハイドロジェンポリシロキサンのみを使用し、該オルガノハイドロジェンポリシロキサン中のＹのうち、少なくとも10モル％、即ち10〜100モル％、好ましくは30〜100モル％、より好ましくは50〜100モル％は水素原子でなければならない。
【００１６】
R²およびYのうち、炭素数１〜８のアルキル基、炭素数６〜１０のアリール基、炭素数７〜１０のアラルキル基、およびこれらの基の炭素原子に結合する水素原子の少なくとも一部をハロゲン原子で置換した基の具体例は、一般式(1)のR¹およびXについて例示した、アルケニル基以外の基と同様であるが、入手のし易さから、R²はメチル基、フェニル基が好ましく、また水素原子以外のＹはメチル基、フェニル基が好ましい。
一般式(2)において、ｍ，ｎは各々１≦ｍ＋ｎ≦500、好ましくは１≦ｍ＋ｎ≦200、より好ましくは８≦ｍ＋ｎ≦100の範囲を満足する０または正の整数である。具体的には、ｍは好ましくは０〜200、より好ましくは０〜100、特に好ましくは０〜50程度の整数であり、ｎは好ましくは１〜300、より好ましくは１〜200、特に好ましくは４〜50程度の整数である。
【００１７】
（Ｂ）成分の具体例としては、Me₃SiO-[SiH(Me)O] ₄₀-SiMe₃（Meはメチル基を示す。以下同様）、HSiMe₂O-[SiH(Me)O] ₄₀-SiMe₂H、HSiMe₂O-(SiMe₂O) ₈-SiMe₂H、Me₃SiO-[SiH(Me)O] ₂₀-(SiMe₂O) ₂₀-SiMe₃、C₆H₅SiH₃、HSiMe₂O-SiMe₂H等が挙げられる。
これらは単独で、または２種以上組み合わせて使用することができる。但し、末端に珪素原子結合水素原子（即ち、SiH基）を有さない化合物（例えば両末端がトリオルガノシロキシ基で封鎖されたオルガノハイドロジェンポリシロキサン）を用いる時は、末端にSiH基を有する化合物、例えばジオルガノハイドロジェンシロキシ基で封鎖されたオルガノハイドロジェンポリシロキサン及び／又はオルガノハイドロジェンシランを混合し、混合物中の全末端基Ｙとオルガノハイドロジェンシラン中のSiH基との合計のうち、10モル％以上が水素原子となるように調製して用いる必要がある。
（Ｂ）成分の使用量は（Ａ）成分１００重量部に対し、１〜５０重量部、特に２〜３０重量部が適当である。
【００１８】
（Ｃ ) 成分の活性水素基を有する化合物
（Ｃ）成分は、水、１価〜３価の（Ｅ）成分以外のアルコール、オルガノヒドロキシシラン、および珪素原子数２〜５０のヒドロキシ基含有オルガノシロキサンオリゴマーから成る群から選択される、単独または２種以上の、活性水素基を有する化合物（即ち、白金触媒の存在下に（Ｂ）成分中のＳｉＨ基と脱水素反応し得る活性を有する水素原子を分子中に含有する化合物）である。（Ｃ）成分は、前述のように、（Ｂ）成分と反応して脱水素反応を起こし、発泡させる発泡剤として使用される。
【００１９】
１価〜３価の（Ｅ）成分以外のアルコールの具体例としては、メタノール、エタノール、ｎ−プロパノール、ｉｓｏ−プロパノール、ブタノール、エチレングリコール、ジエチレングリコール、グリセリン等の炭素数１〜２０程度、好ましくは炭素数１〜１０程度のアルコールが、またオルガノヒドロキシシランの具体例としては、トリメチルシラノール、ジフェニルシランジオール等のオルガノヒドロキシシランが、珪素原子数２〜５０のヒドロキシ基含有オルガノシロキサンオリゴマーの具体例としては、HOSiMe₂O-(SiMe₂)_{0 〜 40}-SiMe₂OH；Me₃SiO-[SiMe(OH)]-O-[SiMe(OH)]-O-SiMe₃ 等のヒドロキシ基含有オルガノシロキサンオリゴマーが挙げられる。
これらは単独で、または２種以上組み合わせて使用することができる。使用量は（Ａ）成分１００重量部に対し、０．１〜２０重量部、特に０．２〜１０重量部が適当である。
【００２０】
（Ｄ ) 成分の白金触媒
（Ｄ）成分の白金触媒は、塩化白金酸もしくはこれより誘導される各種錯体である。白金触媒としては、白金ブラック；塩化白金酸；塩化白金酸のアルコール変性物；塩化白金酸とオレフィン、アルデヒド、ビニルシロキサンまたはアセチレンアルコール類等との錯体等が例示される。その使用量は、白金原子として、組成物に対し通常１ppm以上、例えば１〜１０００ppm、好ましくは２〜５００ppmである。
【００２１】
（Ｅ）成分のアセチレンアルコール系化合物
（Ｅ）成分のアセチレンアルコール系化合物は、混合機を用いた機械的混合時に発泡硬化反応が起こらないように抑制剤として使用される。
この抑制剤は、通常、付加硬化反応の抑制剤として使用される各種の抑制剤、例えば、ベンゾトリアゾール系化合物（特公昭40-25069号公報）、アセチレンアルコール系化合物〔特公昭44-31476号公報（USP 3,445,420対応）〕、ビニル基含有ポリシロキサン化合物〔特公昭48-10947号公報（USP 3,699,073対応）〕、ハイドロパーオキサイド〔特公昭57-20340号公報（USP 4,061,609対応）〕、アミン系化合物〔特開昭63-56563号公報（USP 4,785,066およびUSP 5,004,792対応）〕の中から本発明の組成物に最適な抑制剤として選択されたものである。具体的には、３−メチル−１−ブチン−３−オール、３−メチル−１−ペンチン−３−オール、エチニルシクロヘキサノール、３，５−ジメチル−１−ヘキシン−３−オール等が挙げられる。
これらは単独で、または２種以上組み合わせて使用することができる。使用量は（Ａ）成分１００重量部に対し、０．００１〜２０重量部が適当である。
【００２２】
添加剤
本発明の組成物には上記（Ａ）〜（Ｅ）成分の他に、各種添加剤を併用することができる。例えば、硬化物に機械的強度を与えるために充填剤を添加することができる。充填剤の例としては、煙霧状焼成シリカ、沈降性シリカ、結晶性粉砕シリカ、コロイダル炭酸カルシウム、沈降炭酸カルシウム、重質炭酸カルシウム、アセチレンブラック、ファーネスカーボン、酸化チタン、金属酸化物、および金属酸化物表面をシラン化合物またはシロキサン化合物で処理したもの等が挙げられる。充填剤の使用量は（Ａ）成分１００重量部に対し、０〜３００重量部が適当である。
その他、この分野で公知のチクソ性向上剤、接着性向上剤、可塑剤としてのシリコーンオイルなどの添加剤を本発明の目的を阻害しない範囲で添加することができる。
【００２３】
【実施例】
以下に本発明を実施例によって説明する。なお、部は全て重量部である。またMeはメチル基を示す。
実施例１
25℃での粘度が10,000 cStの、分子鎖両末端がビニルジメチルシリル基で封鎖されたジメチルポリシロキサン（ビニル基含有量：分子中の珪素原子に結合した全メチル基とビニル基との合計に対して0.19モル％）100部、表面がジメチルジクロロシランで処理された比表面積が200m²の煙霧状シリカ10部を均一に混合してベースを作製した。
このベース100部に対して、塩化白金酸から誘導したシロキサン変性された白金触媒を白金原子（重量換算で）として100ppm、およびイソプロピルアルコール0.5部を添加し、均一に混合攪拌しAサイドとした。
ついで、前記ベース100部に対してエチニルシクロヘキサノール0.1部、および平均組成式：HSiMe₂O-[SiH(Me)O]₄₀-SiMe₂Hで示される、末端および側鎖に珪素原子結合水素原子(SiH基)を含有するメチルハイドロジェンポリシロキサン10部を添加して、Bサイドとした。AサイドとBサイドとの混合物が加熱硬化型発泡性オルガノポリシロキサン組成物である。
【００２４】
実施例２
Aサイドとして実施例１と同じものを用意した。
ついで、実施例１で作製したベース100部に対してエチニルシクロヘキサノールを0.1部、実施例１と同じ平均組成式で示される、末端および側鎖にSiH基を含有するメチルハイドロジェンポリシロキサン８部、および平均組成式： HSiMe₂O-(SiMe₂O)₈-SiMe₂Hで示される、両末端にSiH基を含有するメチルハイドロジェンポリシロキサン２部を添加して、Bサイドとした。
【００２５】
実施例３
Aサイドとして実施例１と同じものを用意した。
ついで、実施例１で作製したベース100部に対してエチニルシクロヘキサノール0.1部、平均組成式：Me₃SiO-[SiH(Me)O]₄₀-SiMe₃で示される、側鎖にSiH基を含有するメチルハイドロジェンポリシロキサン８部、および平均組成式： HSiMe₂O-SiMe₂Hで示される、両末端にSiH基を含有するメチルハイドロジェンポリシロキサン２部を添加して、Bサイドとした。このメチルハイドロジェンポリシロキサン混合物中において、末端基であるHSi(Me)₂O_1/2単位とMe₃SiO_1/2単位とのモル比は８３：１７である。
【００２６】
比較例１
Aサイドとして実施例１と同じものを用意した。
ついで、実施例１で作製したベース100部に対してエチニルシクロヘキサノールを0.1部、および実施例３で用いた平均組成式：Me₃SiO-[SiH(Me)O]₄₀-SiMe₃で示される、側鎖にSiH基を含有するメチルハイドロジェンポリシロキサン10部を添加して、Bサイドとした。
【００２７】
試験方法
各例で得られたAサイドおよびBサイドを等量（重量）採り、手混合による攪拌で混合したサンプルと、スタティックミキサーを用いて機械的に混合したサンブルを調製した。これを、アルミシャーレに一定量採り、110℃の乾燥機中に20分間放置して発泡、硬化させ、発泡セルの状態（均一性および大きさ）を評価した。その結果を表１に示す。
【００２８】
【表１】

【００２９】
表１から、発泡剤兼架橋剤として、末端にSiH基を有するオルガノハイドロジェンポリシロキサンを含有し、且つ反応抑制剤として、アセチレンアルコール系化合物を含有する加熱硬化型発泡性オルガノポリシロキサン組成物は、常温での保存安定性を有し、且つ加熱工程によって均一なセルを有する発泡体を形成できることが判る。
【００３０】
【発明の効果】
本発明の加熱硬化型発泡性オルガノポリシロキサン組成物は、常温での保存安定性を有し、且つ加熱工程を含む量産ラインにおいて均一な発泡セルを有する発泡体を形成することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a thermosetting foamable organopolysiloxane composition useful for building materials, automobile materials, and the like, and a method for curing the composition.
[0002]
[Prior art]
In recent years, organopolysiloxane (silicone) foams have been widely used in building materials, automobile materials, and the like due to the excellent weather resistance and heat resistance of organopolysiloxane polymers. Along with this, the foam material that is the raw material of these materials is usually divided into two or more liquid compositions (called side or pack), so how to efficiently mix these divided foam materials becomes an important issue. It is coming.
[0003]
The foam material and its curing method that have been used so far are a method in which a room temperature curable foam material consisting of two or more liquids is weighed, mixed by hand, and then discharged to a predetermined place to foam and cure. I came. However, in order to make it more suitable for mass production line work, the foam material is changing from room temperature curing type to heat curing type, and the mixing means is changing from manual mixing to mechanical mixing by a mixer. Changing the foamed material to a heat-curing type is useful in terms of quality because it is not affected by an increase in line speed or outside air temperature, and mechanical mixing is effective in preventing measurement errors and uneven mixing.
[0004]
[Problems to be solved by the invention]
However, if the conventional room temperature curable foam material is used as it is as a heat curable foam material, foaming and curing will start at room temperature when mixing each composition, and a uniform foam cell cannot be secured in the mass production line. It was.
Accordingly, an object of the present invention is to provide a thermosetting foamable organopolysiloxane composition having a storage stability at room temperature and capable of forming a foam having uniform foam cells in a mass production line including a heating process, and a curing method thereof. Is to provide.
[0005]
[Means for Solving the Problems]
In order to use the room temperature curable foam material as the heat curable foam material, it is necessary to suppress the curing reaction until the heating process is started. As a result of various studies on such a curing reaction inhibitor, the present inventor has conventionally found that an addition-curable foaming organopolysiloxane composition (an alkenyl group-containing organopolysiloxane as a base polymer and an organohydrogensilane as a crosslinking agent / foaming agent). It has been found that among the compounds used as inhibitors of the addition reaction in (including siloxane and / or siloxane), acetylene alcohol-based compounds give remarkable results even in small amounts. However, the acetylene alcohol-based compound has a great inhibitory effect, and simply adding this compound to a conventional room temperature curable foam material results in suppression of initial foaming by dehydrogenation to obtain a uniform cell. Therefore, as a result of further investigation, side chains that have been conventionally used in organohydrogensilanes and / or siloxanes, which are crosslinking agents and foaming agents, used so far in addition-curable foamable organopolysiloxane compositions. A hydrogen group (that is, SiH (R ² ) O _2/2 (wherein R ² has the same meaning as defined in the general formula (2) described later. The same applies hereinafter)) Hydrogen groups (ie containing SiH (R ² ) ₂ O _1/2 units) or end- and side-chain combined hydrogen groups (ie SiH (R ² ) O _2/2 units and SiH (R ² ) ₂ O _1/2 units containing) or to change the type, or the terminal hydrogen groups type or terminal-side chain combined hydrogen group type in combination with hydrogen radicals as the conventional side-chain hydrogen radical type (i.e., to the silicon atom To make the reactivity of the group containing a bonded hydrogen atom more active More, it was found that the sufficient initial fine foam obtained to obtain a uniform foamed cell even in a small amount even composition using acetylene alcohol compounds have remarkable effect as inhibitors. The present invention is based on these findings.
That is, the thermosetting foamable organopolysiloxane composition of the present invention is
( A) General formula (1):
[0006]
[Chemical 3]

[0007]
(Wherein R ¹ and X are each an alkyl group having 1 to 8 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, a hydroxyl group, and These groups are selected from the group consisting of a group in which at least a part of hydrogen atoms bonded to carbon atoms are substituted with halogen atoms, and at least one of the total of all R ¹ groups and X groups is an alkenyl group or (P is a positive integer such that the viscosity at 25 ° C. is 100 to 100,000 cSt.)
And an organopolysiloxane containing an alkenyl group, a hydroxyl group or a mixed group thereof in a molecule in an amount of 0.01 to 5 mol% based on the total of all R ¹ groups and X groups in the molecule,
(B) As an organohydrogensilicon compound having a hydrogen atom bonded to a silicon atom, only an organohydrogensiloxane represented by the following general formula (2) and having at least two hydrogen atoms bonded to a silicon atom in one molecule : 1 to 50 parts by weight per 100 parts by weight of the component (A)
General formula (2):
[0008]
[Formula 4]

[0009]
Wherein R ² is an alkyl group having 1 to 8 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, and at least a part of hydrogen atoms bonded to carbon atoms of these groups. Are selected from the group consisting of a group substituted with a halogen atom, and Y is an alkyl group having 1 to 8 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, and a carbon atom of these groups. It is selected from the group consisting of a group in which at least part of the bonded hydrogen atoms are substituted with halogen atoms, and hydrogen atoms , provided that at least 10 mol% of the total of Y are hydrogen atoms, and m and n are each 1 ≦ m + n ≦ 500 that satisfies 0 or a positive integer. )
(C) One or more selected from the group consisting of water, alcohols other than the monovalent to trivalent (E) component, organohydroxysilane, and hydroxy group-containing organosiloxane oligomer having 2 to 50 silicon atoms A compound having an active hydrogen group : 0.1 to 20 parts by weight per 100 parts by weight of the component (A)
(D) Platinum catalyst : 1 to 1000 ppm as platinum atom in the present composition, and (E) acetylene alcohol-based compound : 0.001 to 20 parts by weight per 100 parts by weight of component (A) Do it.
The curing method of the present invention is characterized in that after the above composition is mechanically and uniformly mixed, it is heated to 40 ° C. or more to be foamed and cured.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Below, each component of this invention composition is demonstrated.
The organopolysiloxane (A) component as the component (A) is used as a base polymer and is represented by the general formula (1).
In the general formula (1), R ¹ and X are an alkyl group having 1 to 8 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, a hydroxyl group And at least part of the hydrogen atoms bonded to the carbon atoms of these groups is selected from the group consisting of halogen atoms, and at least one of the total of all R ¹ groups and X groups is an alkenyl group or The hydroxyl group is preferably one having two or more alkenyl groups or hydroxyl groups in the molecule, particularly one having at least both alkenyl groups or hydroxyl groups at both ends of the molecular chain. R ¹ and X other than the alkenyl group and the hydroxyl group may each be a single group or two or more groups selected from the above group.
[0011]
The alkenyl group and hydroxyl group in the general formula (1) are functional groups that contribute to the crosslinking reaction, and the alkenyl group, hydroxyl group, or mixed group thereof is bonded to either the silicon atom at the end of the molecular chain or the silicon atom in the middle of the molecular chain. However, these groups are contained in an amount of 0.01 to 5 mol%, preferably 0.1 to 3 mol%, based on the total of all R ¹ groups and X groups in the molecule. It must be. P is a positive integer such that the viscosity at 25 ° C. is 100 to 100,000 cSt, preferably 500 to 50,000 cSt.
[0012]
Examples of the alkyl group having 1 to 8 carbon atoms include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl and octyl groups. Examples of the aryl group having 6 to 10 carbon atoms include phenyl, tolyl, xylyl, ethylphenyl and naphthyl groups. Examples of the aralkyl group having 7 to 10 carbon atoms include benzyl, phenylethyl and phenylpropyl groups. Examples of the alkenyl group having 2 to 8 carbon atoms include vinyl, allyl, propenyl, isopropenyl, butenyl, isobutenyl and hexenyl groups. Examples of the group in which at least a part of the hydrogen atoms bonded to the carbon atoms of these groups are substituted with a halogen atom include 3,3,3-trifluoropropyl, chloromethyl, bromoethyl groups and the like.
In view of easy availability and cost, X is preferably a vinyl group or a hydroxyl group, and R ¹ is preferably a methyl group, a phenyl group or a 3,3,3-trifluoropropyl group.
Specifically, as the organopolysiloxane of component (A), both ends of the molecular chain are blocked with vinyldimethylsiloxy groups or both ends of the molecular chain with hydroxydimethylsiloxy groups, and in the main chain diorganosiloxane repeating unit. And a straight-chain diorganopolysiloxane such as a straight-chain dimethylpolysiloxane that does not contain an alkenyl group and a hydroxyl group.
[0013]
The component (A) includes a resin basically composed of R ¹ ₃ SiO _1/2 (R ¹ is the same as described above) and SiO ₂ in order to improve the strength of the foam, for example, (CH ₃ ) ₃ SiO _1/2 and (CH ₂ = CH) (CH ₃ ) ₂ SiO _1/2 and SiO ₂ and (CH ₃ ) ₃ SiO _1/2 and (CH ₂ = CH) (CH ₃ ) ₂ SiO _{1 / A} toluene-soluble vinyl group-containing silicone resin having a ratio (molar ratio) of the total amount of _{2 to} the amount of SiO ₂ of 0.6 to 1.2 may be added.
[0014]
(B) organohydrogen silicon compound component represented by the above general formula (2) (B) organohydrogen silicon compound of the component, at least a hydrogen atom bonded to a silicon atom in a molecule (i.e., SiH groups) 2, preferably organohydrogen siloxanyl emissions containing 3 or more, with reacts to the crosslinking reaction with component (a) undergoes a dehydrogenation reaction by reacting with the component (C), foaming Used as a crosslinker and foaming agent.
[0015]
Oite the general formula (2), R ² is hydrogen bonded to the carbon atom of the alkyl group, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, and these groups having 1 to 8 carbon atoms In the general formula (2), Y is an alkyl group having 1 to 8 carbon atoms, an aryl group having 6 to 10 carbon atoms, or 7 carbon atoms. Selected from the group consisting of 10 to 10 aralkyl groups, a hydrogen atom, and a group in which at least a part of the hydrogen atoms bonded to the carbon atoms of these groups are substituted with a halogen atom . As the component (B), only the organohydrogenpolysiloxane of the general formula (2) is used , and at least 10 mol% of Y in the organohydrogenpolysiloxane, that is, 10 to 100 mol%, preferably 30 to 100 mol%. The mol%, more preferably 50-100 mol% must be hydrogen atoms.
[0016]
Among R ² and Y, an alkyl group having 1 to 8 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, and at least a part of hydrogen atoms bonded to carbon atoms of these groups Specific examples of the group in which is substituted with a halogen atom are the same as the groups other than the alkenyl group exemplified for R ¹ and X in the general formula (1), but for ease of availability, R ² is a methyl group, A phenyl group is preferable, and Y other than a hydrogen atom is preferably a methyl group or a phenyl group.
In the general formula (2), m and n are each 0 or a positive integer satisfying a range of 1 ≦ m + n ≦ 500, preferably 1 ≦ m + n ≦ 200, more preferably 8 ≦ m + n ≦ 100. Specifically, m is preferably an integer of about 0 to 200, more preferably 0 to 100, particularly preferably about 0 to 50, and n is preferably 1 to 300, more preferably 1 to 200, particularly preferably. It is an integer of about 4-50.
[0017]
Specific examples of the component (B) include Me ₃ SiO— [SiH (Me) O] ₄₀ —SiMe ₃ (Me represents a methyl group; the same shall apply hereinafter), HSiMe ₂ O— [SiH (Me) O] ₄₀ — _{SiMe 2 H, HSiMe 2 O- (} SiMe 2 O) 8 -SiMe 2 H, Me 3 SiO- [SiH (Me) O] 20 - (SiMe 2 O) 20 -SiMe 3, C 6 H 5 SiH 3, HSiMe ₂ O-SiMe ₂ H and the like.
These can be used alone or in combination of two or more. However, when using a compound that does not have a silicon-bonded hydrogen atom (that is, SiH group) at the terminal (for example, an organohydrogenpolysiloxane blocked at both ends with a triorganosiloxy group), it has a SiH group at the terminal. Compound, for example, organohydrogenpolysiloxane blocked with diorganohydrogensiloxy group and / or organohydrogensilane is mixed, and out of the total of all terminal groups Y in the mixture and SiH group in organohydrogensilane It is necessary to prepare and use so that 10 mol % or more becomes a hydrogen atom.
(B) The usage-amount of a component is 1-50 weight part with respect to 100 weight part of (A) component, and 2-30 weight part is suitable especially.
[0018]
(C) Compound (C) component having an active hydrogen group of the component, water, monovalent to trivalent (E) other than the component alcohols, organo hydroxy silanes and hydroxy group-containing organosiloxane of silicon atoms from 2 to 50, Single or two or more compounds having an active hydrogen group selected from the group consisting of oligomers (that is, hydrogen atoms having an activity capable of dehydrogenating with SiH groups in component (B) in the presence of a platinum catalyst) In the molecule) . As described above, the component (C) reacts with the component (B) to cause a dehydrogenation reaction and is used as a foaming agent for foaming.
[0019]
Monovalent Examples of A alcohol other than to trivalent component (E), methanol, ethanol, n- propanol, iso- propanol, butanol, ethylene glycol, diethylene glycol, 1-20 degree atoms such as glycerin, preferably specific examples of a alcohol of 1 to 10 carbon atoms, also organo hydroxy silane, trimethyl silanol organo hydroxy silanes such as diphenyl silane diol, silicon atoms from 2 to 50 hydroxy group-containing organosiloxane oligomer specific _{examples, HOSiMe 2 O- (SiMe 2)} 0 ~ 40 -SiMe 2 OH; Me 3 SiO- [SiMe (OH)] - O- [SiMe (OH)] - human Dorokishi group containing such O-SiMe ₃ organosiloxane oligomer over, and the like.
These can be used alone or in combination of two or more. The amount used is suitably 0.1 to 20 parts by weight, particularly 0.2 to 10 parts by weight, per 100 parts by weight of component (A).
[0020]
Platinum catalyst of component (D ) The platinum catalyst of component (D ) is chloroplatinic acid or various complexes derived therefrom. Examples of the platinum catalyst include platinum black; chloroplatinic acid; alcohol-modified chloroplatinic acid; a complex of chloroplatinic acid and olefin, aldehyde, vinylsiloxane, acetylene alcohol, and the like. The amount used is usually 1 ppm or more, for example 1 to 1000 ppm, preferably 2 to 500 ppm, based on the composition as platinum atoms.
[0021]
(E) Acetylene alcohol compound of component (E) The acetylene alcohol compound of component (E) is used as an inhibitor so as not to cause a foam curing reaction during mechanical mixing using a mixer.
These inhibitors are usually various inhibitors used as inhibitors for addition curing reactions, such as benzotriazole compounds (Japanese Patent Publication No. 40-25069), acetylene alcohol compounds [Japanese Patent Publication No. 44-31476]. (Corresponding to USP 3,445,420)], vinyl group-containing polysiloxane compound [Japanese Patent Publication No. 48-10947 (corresponding to USP 3,699,073)], hydroperoxide [Japanese Patent Publication No. 57-20340 (corresponding to USP 4,061,609)], amine compounds [ JP-A 63-56563 (corresponding to USP 4,785,066 and USP 5,004,792)] was selected as an optimum inhibitor for the composition of the present invention. Specific examples include 3-methyl-1-butyn-3-ol, 3-methyl-1-pentyn-3-ol, ethynylcyclohexanol, 3,5-dimethyl-1-hexyn-3-ol, and the like. .
These can be used alone or in combination of two or more. The amount used is suitably 0.001 to 20 parts by weight per 100 parts by weight of component (A).
[0022]
Additives In addition to the components (A) to (E), various additives can be used in combination with the composition of the present invention. For example, a filler can be added to give the cured product mechanical strength. Examples of fillers include fumed silica, precipitated silica, crystalline ground silica, colloidal calcium carbonate, precipitated calcium carbonate, heavy calcium carbonate, acetylene black, furnace carbon, titanium oxide, metal oxide, and metal oxide The thing surface processed with the silane compound or the siloxane compound etc. are mentioned. The amount of filler used is suitably 0 to 300 parts by weight per 100 parts by weight of component (A).
In addition, additives such as thixotropic improvers, adhesive improvers, and silicone oil as a plasticizer known in this field can be added within a range that does not impair the object of the present invention.
[0023]
【Example】
The present invention will now be described by examples. All parts are parts by weight. Me represents a methyl group.
Example 1
Dimethylpolysiloxane having a viscosity of 10,000 cSt at 25 ° C and both ends of the molecular chain blocked with vinyldimethylsilyl groups (vinyl group content: total of all methyl groups and vinyl groups bonded to silicon atoms in the molecule) The base was prepared by uniformly mixing 100 parts of 0.19 mol%) and 10 parts of fumed silica having a specific surface area of 200 m ² treated with dimethyldichlorosilane on the surface.
To 100 parts of this base, 100 ppm of a siloxane-modified platinum catalyst derived from chloroplatinic acid as a platinum atom (in terms of weight) and 0.5 part of isopropyl alcohol were added and mixed uniformly and stirred to obtain the A side.
Next, 0.1 part of ethynylcyclohexanol with respect to 100 parts of the base, and a silicon atom-bonded hydrogen atom at the terminal and side chain represented by an average composition formula: HSiMe ₂ O— [SiH (Me) O] ₄₀ —SiMe ₂ H 10 parts of methylhydrogenpolysiloxane containing (SiH group) was added to form B side. A mixture of the A side and the B side is a thermosetting foamable organopolysiloxane composition.
[0024]
Example 2
The same A side as in Example 1 was prepared.
Next, 0.1 part of ethynylcyclohexanol with respect to 100 parts of the base prepared in Example 1, and 8 parts of methylhydrogenpolysiloxane containing SiH groups at the terminal and side chains represented by the same average composition formula as in Example 1 , And average composition formula: HSiMe ₂ O— (SiMe ₂ O) ₈ —SiMe ₂ H 2 parts of methylhydrogenpolysiloxane containing SiH groups at both ends were added to obtain a B side.
[0025]
Example 3
The same A side as in Example 1 was prepared.
Next, 0.1 part of ethynylcyclohexanol with respect to 100 parts of the base prepared in Example 1 and an average composition formula: Me ₃ SiO— [SiH (Me) O] ₄₀ —SiMe ₃ , containing a SiH group in the side chain 8 parts of methyl hydrogen polysiloxane and 2 parts of methyl hydrogen polysiloxane containing SiH groups at both ends represented by an average composition formula: HSiMe ₂ O—SiMe ₂ H were added to form a B side. In this methyl hydrogen polysiloxane mixture, the molar ratio of HSi (Me) ₂ O _1/2 units as end groups to Me ₃ SiO _1/2 units is 83:17.
[0026]
Comparative Example 1
The same A side as in Example 1 was prepared.
Next, 0.1 part of ethynylcyclohexanol is used with respect to 100 parts of the base prepared in Example 1, and the average composition formula used in Example 3 is Me ₃ SiO— [SiH (Me) O] ₄₀ —SiMe _3. Then, 10 parts of methylhydrogenpolysiloxane containing SiH group in the side chain was added to form B side.
[0027]
Test method An equal amount (weight) of the A side and B side obtained in each example was taken, and a sample that was mixed by stirring by manual mixing and a sample that was mechanically mixed using a static mixer were prepared. A certain amount of this was taken in an aluminum petri dish and allowed to stand for 20 minutes in a dryer at 110 ° C. for foaming and curing, and the state (uniformity and size) of the foamed cells was evaluated. The results are shown in Table 1.
[0028]
[Table 1]

[0029]
From Table 1, the thermosetting foamable organopolysiloxane composition containing an organohydrogenpolysiloxane having a SiH group at the end as a foaming agent and a crosslinking agent and containing an acetylene alcohol compound as a reaction inhibitor is It can be seen that a foam having storage stability at room temperature and having uniform cells can be formed by a heating process.
[0030]
【The invention's effect】
The heat-curable foamable organopolysiloxane composition of the present invention has storage stability at room temperature and can form a foam having uniform foam cells in a mass production line including a heating step.

Claims (2)

(A) General formula (1):

(Wherein R ¹ and X are each an alkyl group having 1 to 8 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, a hydroxyl group, and These groups are selected from the group consisting of a group in which at least a part of hydrogen atoms bonded to carbon atoms are substituted with halogen atoms, and at least one of the total of all R ¹ groups and X groups is an alkenyl group or (P is a positive integer such that the viscosity at 25 ° C. is 100 to 100,000 cSt.)
And an organopolysiloxane containing an alkenyl group, a hydroxyl group or a mixed group thereof in a molecule in an amount of 0.01 to 5 mol% based on the total of all R ¹ groups and X groups in the molecule,
(B) As an organohydrogensilicon compound having a hydrogen atom bonded to a silicon atom, only an organohydrogensiloxane represented by the following general formula (2) and having at least two hydrogen atoms bonded to a silicon atom in one molecule : 1 to 50 parts by weight per 100 parts by weight of the component (A)
General formula (2):

Wherein R ² is an alkyl group having 1 to 8 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, and at least a part of hydrogen atoms bonded to carbon atoms of these groups. Are selected from the group consisting of a group substituted with a halogen atom, and Y is an alkyl group having 1 to 8 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, and a carbon atom of these groups. It is selected from the group consisting of a group in which at least part of the bonded hydrogen atoms are substituted with halogen atoms, and hydrogen atoms , provided that at least 10 mol% of the total of Y are hydrogen atoms, and m and n are each 1 ≦ m + n ≦ 500 that satisfies 0 or a positive integer ).
(C) One or more selected from the group consisting of water, alcohols other than the monovalent to trivalent (E) component, organohydroxysilane, and hydroxy group-containing organosiloxane oligomer having 2 to 50 silicon atoms A compound having an active hydrogen group : 0.1 to 20 parts by weight per 100 parts by weight of the component (A)
(D) Platinum catalyst : 1 to 1000 ppm as platinum atom in the present composition, and (E) acetylene alcohol-based compound : 0.001 to 20 parts by weight per 100 parts by weight of component (A) A heat-curable foamable organopolysiloxane composition.   A curing method comprising: mixing the composition of claim 1 mechanically and uniformly, then heating to 40 ° C. or higher to foam and cure.