JP3799624B2 - Binder composition for friction material and friction material - Google Patents

Description

【００２３】
但し、上記の式（３）において、ｎは、通常３〜２００程度、より好ましくは５から１００程度である。
【００２４】
式（１）、（２）および（３）で示される有機ケイ素化合物としては、より具体的に、ジメチルポリシラン、ジエチルポリシラン、フェニルエチルポリシラン、フェニルメチルポリシラン、ジフェニルポリシラン、ネットワークフェニルポリシランなどが例示され、フェニルエチルポリシラン、フェニルメチルポリシラン、ジフェニルポリシラン、ネットワークフェニルポリシランなどのフェニル基を有するものがより好ましい。
【００２５】
また、上記式（１）、（２）および（３）のＳｉの一部または全部をＧｅ、ＳｎまたはＰｂにより置換した化合物も使用できる。
【００２６】
（ＩＩＩ）縮合促進触媒
熱硬化性樹脂と有機金属化合物との混合物をバインダーとして使用する場合には、熱硬化性樹脂と有機金属化合物との架橋を促進するために、縮合促進触媒を使用することが好ましい。特に好ましい縮合促進触媒としては、下記のものが例示される。
【００２７】
Ａ アミン類：Ｎ，Ｎ−ジメチルベンジルアミン、Ｎ，Ｎ−ジメチルエチレンアミン、２，４，６−トリス（ジメチルアミノメチル）フェノールなど。
【００２８】
Ｂ ルイス酸およびプロトン酸：塩化コバルト、塩化第２鉄、塩化亜鉛、ｐ−トルエンスルホン酸など。
【００２９】
Ｃ 金属：コバルト、鉄、チタン、スズ、銅、亜鉛など。
【００３０】
Ｄ 金属酸化物および金属硫化物：ＣｏＯ、Ｃｏ₃Ｏ₄、Ｃｕ₂Ｏ、ＦｅＯ、ＺｎＯ、ＭｇＯ、ＺｒＯ₂、ＳｎＯ、ＣｕＳ、ＦｅＳ、ＺｎＳ、ＭｏＳなど。金属酸化物および金属硫化物は、同一金属であれば、酸化状態が低い程好ましい（例えば、ＣｕＯよりはＣｕ₂Ｏの方が好ましい）。
【００３１】
熱硬化性樹脂および有機金属化合物と混合して使用される縮合促進触媒が固体である場合には、粒子径が小さいほど高い効果が期待される。しかしながら、超微粒子は、高価であるため、好ましくは１０μｍ以下程度の粒子、より好ましくは３μｍ以下程度の粒子を使用する。
【００３２】
（ＩＶ）熱硬化性樹脂と有機金属化合物との配合割合
熱硬化性樹脂（ピッチを配合する場合には、ピッチを配合した複合体を熱硬化性樹脂として扱う）と有機金属化合物との配合割合は、通常前者９９．９９〜７０質量％に対し後者０．０１〜３０質量％程度、好ましくは前者９９．９５〜８０質量％に対し後者０．０５〜２０質量％程度、特に好ましくは前者９９．９０〜９０質量％に対し後者０．１〜１０質量％程度とする。
【００３３】
縮合促進触媒の配合割合は、有機金属化合物と熱硬化性樹脂との混合物に対し、０．０１〜３０質量％程度、好ましくは０．１〜１５質量％程度、より好ましくは１〜１０質量％程度である。
【００３４】
摩擦材の構成成分中に金属、金属酸化物、金属硫化物などが含まれている場合には、縮合促進触媒の添加量を減らしても良い。この様な場合には、予め熱硬化性樹脂および有機金属化合物と縮合促進触媒とを均一に混合した後、摩擦材の構成成分と混合することにより、反応を効果的に促進することができる。
【００３５】
さらに、熱硬化性樹脂、有機金属化合物および縮合促進触媒の混合物がバインダーとしての能力を失わない温度、すなわちバインダーの硬化反応開始温度以下の温度で熱処理を行う場合には、反応を部分的に進行させることができるので、バインダーの炭素化収率を効果的に向上させることができる。
【００３６】
（Ｖ）熱硬化性樹脂、有機金属化合物および縮合促進触媒の混合方法
これらの混合は、これらが常温で固体である場合には、その粉末を混合する方法；クロロホルム、クロロベンゼン、エタノール等の溶媒中でこれらを混合した後、溶媒を除去する方法などにより、またピッチを使用する場合には、ピッチを加熱溶融した後、有機金属化合物を混合する方法などにより行なうことができる。熱硬化性樹脂が１００〜２３０℃の温度で溶融する場合には、これに有機金属化合物を混合することもできる。熱硬化性樹脂の合成過程で有機金属化合物を添加しておく方法も、有効である。また、熱硬化性樹脂が常温で液状の場合には、有機金属化合物を直接混合することができる。これらの場合、得られる混合物の一部は反応するが、残りは未反応の状態で存在する。
【００３７】
（ＶＩ）摩擦材製造用材料
ブレーキ、クラッチなどの摩擦材を製造するためには、上記のバインダー組成物、公知の摩擦調整材、補強繊維などの原料を配合し、常法に従って成形し、熱処理する。
【００３８】
バインダー組成物の使用量は、摩擦調整材および補強繊維の合計質量の５〜２５％程度とする。
【００３９】
摩擦調整材としては、銅、黄銅、青銅、鉄、ステンレス鋼などの金属の粉末および粒子、黒鉛、ＢａＳＯ₄ 、ＣａＣＯ₃ 、ＭｇＣＯ₃ 、シリカ、アルミナ、マグネシア、酸化クロム、ウォラストナイト、珪藻土、ドロマイト、硫化モリブデン、フッ化カルシウムなどの無機物質の粉末および粒子が使用できる。
【００４０】
摩擦調整材として金属粉末および／または粒子を使用する場合には、金属の種類などにもよるが、添加量は、摩擦材原料中の５〜８０質量％程度とすることが好ましく、１０〜５０質量％程度とすることが特に好ましい。
【００４１】
摩擦調整材として黒鉛を使用する場合には、添加量は、摩擦材原料（摩擦調整材＋補強繊維）中の０．５〜３０質量％程度とすることが好ましく、３〜２０質量％程度とすることが特に好ましい。
【００４２】
また、摩擦調整材としては、カシューダスト、ラバーダストなどの有機物質や熱硬化性樹脂硬化物の粉末および粒子などを用いることができる。有機金属化合物を含む熱硬化性樹脂であるフェノール樹脂、カシュー樹脂などを２００〜３５０℃程度で硬化させたもの、有機金属化合物を含むピッチの硬化物なども使用できる。これらは、摩擦材に要求される性能に応じて、単独でもしくは２種以上を混合して使用する。
【００４３】
通常のフェノール樹脂或いはカシュー樹脂を熱硬化性樹脂とした本発明のバインダー組成物の硬化物としては、該バインダー組成物を１３０〜３００℃程度（より好ましくは１５０〜２５０℃程度）で硬化させた後、２００〜３５０℃程度（より好ましくは２２０〜３００℃程度）で２〜３０時間程度後硬化（ポストキュアー）させることにより得られる。この硬化物は、粉砕し、１μｍ〜１ｍｍ程度に整粒して使用することが好ましい。
【００４４】
さらに、摩擦調整材としてピッチに本発明の有機金属化合物を添加し、加熱硬化させたものを使用することもできる。ピッチとしては、石油系ピッチ、石炭系ピッチおよびナフタレン、アセナフチレンなどの芳香族炭化水素を原料とする合成ピッチ、これらピッチの改質品などのいづれをも使用でき、また等方性ピッチおよび異方性ピッチのいづれをも使用できる。ピッチと有機金属化合物との配合割合は、通常前者９９〜５０質量％に対し後者１〜５０質量％程度であり、より好ましくは前者９５〜７５質量％に対し後者５〜２５質量％程度である。両者の混合は、ピッチを加熱溶融した後、有機金属化合物を混合する方法、両者の粉末を混合する方法、溶媒中で両者を混合する方法などにより行うことができる。このような硬化物からなる摩擦調整材は、ピッチと有機金属化合物とからなる組成物を２００〜４５０℃程度（より好ましくは２５０〜４００℃程度）で硬化させた後、２５０〜４５０℃程度で２〜３０時間程度後硬化（ポストキュアー）させることにより得られる。このような硬化物も、粉砕し、１μｍ〜１ｍｍ程度に整粒して使用することが好ましい。摩擦調整材として、このような硬化物は、通常使用されているフェノール樹脂硬化物、カシュー樹脂硬化物などよりも、ガス、タールなどの発生率を低下させ、耐フェード性を向上させる。
【００４５】
摩擦調整材としてカシューダスト、ラバーダスト、本発明のバインダー組成硬化物などの有機物質を使用する場合には、添加量は、摩擦材原料（摩擦調整材＋補強繊維）中の１〜３０質量％程度とすることが好ましく、３〜１０質量％程度とすることが特に好ましい。
【００４６】
摩擦調整材の粒径は、特に限定されるものではなく、摩擦材に要求される特性などに応じて適宜定めることができる。例えば、金属を使用する場合には、１０μｍ〜５ｍｍ程度、無機物質を使用する場合には、１μｍ〜１ｍｍ程度、有機物質を使用する場合には、１μｍ〜１ｍｍ程度の粒径範囲から選択すれば良い。
【００４７】
補強繊維としては、銅、黄銅、鉄、ステンレス鋼などの金属の繊維体、炭素繊維、ロックウール、アスベスト、セラミックス繊維、ガラス繊維などの無機繊維、アラミド繊維などの有機繊維などを併用することができる。これらの繊維類は、補強効果を発揮するのみならず、摩擦係数を高める効果をも発揮する。
【００４８】
摩擦材原料の混合方法は、特に限定されず、乾式混合方法、少量のバインダーを用いて原料を造粒する方法、湿式混合する方法、湿式抄紙方法などが採用できる。
【００４９】
（ＶＩＩ）摩擦材原料の成形および硬化
原料混合物は、特に限定されるものではないが、例えば、ホットプレスを使用して、成形温度１５０〜４００℃程度、好ましくは１８０〜３００℃程度、成形圧力１〜５０Ｍｐａ程度で、１〜１０分程度の条件下に行なう。成形の過程では、適宜ガス抜きを行なうために、型締め−開放という操作を２〜６回程度繰り返すことが好ましい。また、成形前に高周波、マイクロ波などによる予熱を行なうことも好ましい。
【００５０】
成形後、後硬化（ポストキュアー）として、空気中２００〜３００℃程度で２〜３０時間程度の熱処理を行なう。また、従来から行なわれている５００〜６００℃程度でのスコーチ処理などの高温熱処理も、勿論有効である。
【００５１】
【発明の効果】
有機金属化合物を配合する本発明のバインダー組成物は、有機金属化合物を配合しないバインダー組成物に比して、窒素雰囲気中においても、空気中においても、４９０〜８００℃の温度範囲での熱分解による揮発分の発生が著しく減少する。従って、この様なバインダー組成物を使用する摩擦材においては、熱硬化性樹脂と混合乃至反応している有機金属化合物は、制動時の摩擦熱により、ポリラジカルを発生し、本来ならば分解により揮発する成分を架橋させて高分子化させるとともに、例えばＳｉ−Ｃ結合を導入させるので、摩擦材のフェード性が向上するのみならず、耐熱性および耐摩耗性も大幅に改善される。
【００５２】
【実施例】
以下に実施例および比較例を示し、本発明の特徴とするところをより一層明確にする。
【００５３】
なお、実施例および比較例における揮発分の測定は、以下の様にして行なった。
【００５４】
ＴＧ−ＤＴＡ測定：（株）島津製作所製「ＴＧＡ５０」を用いて、試料１０ｍｇを白金製試料皿に精秤し、５０ｍｌ／分の窒素気流中１０℃／分の昇温速度で常温から４９０℃及び８００℃まで昇温させ、その間の質量減少（％）を測定した。また、窒素に代えて空気を使用する場合には、窒素と同流量で行った。
【００５５】
実施例１
ノボラック型フェノール樹脂（カシュー（株）製、品番“ＮＲ−２２３５”、ヘキサミン系硬化剤１０％を含む）１００質量部に、ネットワークフェニルポリシラン（重量平均分子量ＭＷ６１８４、分散度ＭＷ／ＭＮ＝２．２７、分解温度３６５℃、大阪瓦斯（株）製）５質量部を加え、粉末状態で均一に混合し、空気中１７０℃で２０分間硬化させた後、さらに空気中２００℃で６時間ポストキュアーした。
【００５６】
得られたフェノール樹脂−ポリシラン複合体を約６０メッシュに粉砕し、得られた粉砕物の揮発分を窒素気流中４９０℃と８００℃で測定した。
【００５７】
本実施例の結果を実施例２〜７および比較例１〜４の結果と併せて下記表１に示す。
【００５８】
実施例２
ネットワークフェニルポリシランの添加量を３質量部とする以外は実施例１と同様にしてフェノール樹脂−ポリシラン複合体の粉砕物を調製し、その粉砕物の揮発分を窒素気流中４９０℃と８００℃で測定した。
【００５９】
実施例３
ネットワークフェニルポリシランに代えてジフェニルポリシラン（重量平均分子量ＭＷ１７５６、分散度ＭＷ／ＭＮ＝４．６９、分解温度３７３℃、大阪瓦斯（株）製）を５質量部使用する以外は実施例１と同様にしてフェノール樹脂−ポリシラン複合体の粉砕物を調製し、その粉砕物の揮発分を窒素気流中４９０℃と８００℃で測定した。
【００６０】
実施例４
ノボラック型フェノール樹脂に代えてレゾール型フェノール樹脂（鐘紡（株）製、品番“Ｓ−８９９”）を１００質量部使用する以外は実施例１と同様にして、フェノール樹脂−ポリシラン複合体の粉砕物を調製し、その粉砕物の揮発分を窒素気流中４９０℃と８００℃で測定した。
【００６１】
実施例５
ノボラック型フェノール樹脂に代えてレゾール型フェノール樹脂１００質量部を使用し、ネットワークフェニルポリシランの使用量を１０質量部とする以外は実施例１と同様にして、フェノール樹脂−ポリシラン複合体の粉砕物を調製し、その粉砕物の揮発分を窒素気流中４９０℃と８００℃で測定した。
【００６２】
実施例６
ネットワークフェニルポリシランの使用量を２５質量部とする以外は実施例１と同様にして、フェノール樹脂−ポリシラン複合体の粉砕物を調製し、その粉砕物の揮発分を空気気流中４９０℃と８００℃で測定した。
【００６３】
実施例７
（１）ポリシラン／ピッチ複合体Ａの調製
ストレートコールタールピッチ（軟化点８４．２℃、キノリン不溶分５．４質量％、ベンゼン不溶分２２．７質量％）１００質量部に実施例３と同じジフェニルポリシラン１０質量部を配合し、オートクレーブ中で窒素雰囲気下に３５０℃で３時間熱共重合させて、ポリシラン／ピッチ複合体Ａを調製した。
【００６４】
（２）ポリシラン／フェノール樹脂複合体Ｂの調製
実施例１と同じノボラック型フェノール樹脂１００質量部に実施例３と同じジフェニルポリシラン１０質量部を配合し、粉末状態で均一に混合し、ポリシラン／フェノール樹脂複合体Ｂを調製した。
【００６５】
（３）複合体Ｃの調製
上記で得た複合体Ａの３質量部と複合体Ｂの７質量部とを粉末状態で均一に混合した後、空気中２４０℃で１２時間キュアーして、複合体Ｃを調製した。
【００６６】
（４）複合体Ｃの揮発分の測定
上記で得られた複合体Ｃを粉砕し、得られた粉砕物の揮発分を実施例１と同様にして窒素気流中４９０℃と８００℃で測定した。
【００６７】
比較例１
ネットワークフェニルポリシランを配合することなく、実施例１に準じてノボラック型フェノール樹脂を空気中１７０℃で２０分間加熱して硬化し、さらに空気中２００℃で６時間ポストキュアーした。得られた硬化体を約６０メッシュに粉砕し、得られた粉砕物の揮発分を窒素気流中４９０℃と８００℃で測定した。
【００６８】
比較例２
ネットワークフェニルポリシランを配合することなく、実施例４と同じレゾール型フェノール樹脂を空気中１７０℃で２０分間加熱して硬化し、さらに空気中２００℃で６時間ポストキュアーした。得られた硬化体を約６０メッシュに粉砕し、得られた粉砕物の揮発分を窒素気流中４９０℃と８００℃で測定した。
【００６９】
比較例３
ネットワークフェニルポリシランを配合することなく、実施例６に準じてノボラック型フェノール樹脂を空気中１７０℃で２０分間加熱して硬化し、さらに空気中２００℃で６時間ポストキュアーした。得られた硬化体を約６０メッシュに粉砕し、得られた粉砕物の揮発分を空気気流中４９０℃と８００℃で測定した。
【００７０】
比較例４
実施例７のストレートコールタールピッチ１００質量部をオートクレーブ中で窒素雰囲気下に３５０℃で３時間加熱した。これを３質量部とノボラック型フェノール樹脂粉末７質量部とを、室温で粉末状態で均一に混合した後、空気中２４０℃で１２時間キュアーして、ピッチ／フェノール樹脂複合体を調製した。得られた複合体を約６０メッシュに粉砕して揮発分を窒素気流中４９０℃と８００℃で測定した。
【００７１】
【表１】

【００７２】
表１に示す結果から、本発明によれば、Ｓｉ−Ｃ結合の導入により、バインダー組成物の炭素化収率が向上し、摩擦材の耐熱性が大幅に向上することが明らかである。
【００７３】
例えば、実施例１（ノボラック型フェノール樹脂＋ネットワークフェニルポリシランの併用）と比較例１（ノボラック型フェノール樹脂単独使用）とを対比すれば、前者では高温での揮発分の発生量が著しく減少している。
【００７４】
また、実施例４（レゾール型フェノール樹脂＋ネットワークフェニルポリシランの併用）と比較例２（レゾール型フェノール樹脂単独使用）とを対比すると、前者では高温での揮発分の発生量が著しく減少している。
【００７５】
さらに、実施例６（ノボラック型フェノール樹脂＋ネットワークフェニルポリシランの併用）と比較例３（ノボラック型フェノール樹脂単独使用）とを比較すると、前者では高温空気中での揮発分（酸化消耗量）が著しく減少している。
【００７６】
さらにまた、実施例７（ピッチ＋ジフェニルポリシラン＋ノボラック型フェノール樹脂の併用）と比較例４（ピッチ＋ノボラック型フェノール樹脂の併用）とを比較すると、前者では窒素気流中で高温での揮発分の発生量が著しく減少していることが明らかである。
【００７７】
実施例８
レゾール型フェノール樹脂（鐘紡（株）製、品番“Ｓ−８９５”）１００質量部と実施例１と同じネットワークフェニルポリシラン１０質量部とを粉末状態で均一混合し、得られた混合物１００質量部にエタノール１００質量部を加えて室温で撹拌混合し、エバポレーターで溶媒を除去し、さらに真空乾燥器中４０℃で４時間乾燥した。得られた乾燥物を窒素雰囲気中２５０℃で１時間保持して硬化させた。得られたフェノール樹脂−ポリシラン複合体を約６０メッシュに粉砕し、得られた粉砕物の揮発分を窒素気流中８００℃で測定した。
【００７８】
本実施例の結果を実施例９〜１４および比較例５の結果とともに表２に示す。
【００７９】
実施例９
実施例８と同じレゾール型フェノール樹脂１００質量部に、実施例１と同じネットワークフェニルポリシラン１０質量部を粉末状態で均一混合し、得られた混合物１００質量部に縮合促進触媒としてのＺｎＣｌ₂３質量部とエタノール１００質量部とを加えて室温で撹拌混合し、エバポレーターで溶媒を除去し、さらに真空乾燥器中４０℃で４時間乾燥した。得られた乾燥物を窒素雰囲気中２５０℃で１時間保持して硬化させた。得られたフェノール樹脂−ポリシラン複合体を約６０メッシュに粉砕し、得られた粉砕物の揮発分を窒素気流中８００℃で測定した。
【００８０】
実施例１０〜１４
実施例９のＺｎＣｌ₂に代えて、ＣｏＣｌ₂・６Ｈ₂Ｏ（実施例１０）、ＦｅＣｌ₃・６Ｈ₂Ｏ（実施例１１）、ｐ−トルエンスルホン酸・１Ｈ₂Ｏ（実施例１２）、２,４，６−トリス（Ｎ，Ｎ−ジメチルアミノメチル）フェノール（実施例１３）、Ｎ，Ｎ−ジメチルベンジルアミン（実施例１４）をそれぞれ３質量部使用する以外は実施例９と同様にして作成した粉砕物の揮発分を窒素気流中８００℃で測定した。
【００８１】
比較例５
実施例８と同じレゾール型フェノール樹脂１００質量部にエタノール１００質量部を加え、攪拌した後、実施例８と同様の条件で乾燥−硬化を行った。
【００８２】
得られた乾燥物を窒素雰囲気中２５０℃で１時間保持して硬化させた。得られたフェノール樹脂−ポリシラン複合体を約６０メッシュに粉砕し、得られた粉砕物の揮発分を窒素気流中８００℃で測定した。
【００８３】
【表２】

【００８４】
実施例１５
実施例８と同じレゾール型フェノール樹脂１００質量部に、実施例１と同じネットワークフェニルポリシラン１０質量部を加えて室温で均一混合し、得られた混合物を窒素雰囲気中２５０℃で１時間保持して硬化させた。得られたフェノール樹脂−ポリシラン複合体を約６０メッシュに粉砕し、得られた粉砕物の揮発分を窒素気流中８００℃で測定した。
【００８５】
本実施例および実施例１６〜２９ならびに比較例６〜８の結果を後記の表３に併せて示す。
【００８６】
実施例１６
実施例８と同じレゾール型フェノール樹脂１００質量部と、 ネットワークフェニルポリシランに代えてネットワークフェニルポリゲルマン（大阪瓦斯（株）製、重量平均分子量ＭＷ８８５、分散度ＭＷ／ＭＮ＝２．３）１０質量部とを用いた以外は、実施例１５と同じ条件で処理を行い、フェノール樹脂−ポリゲルマン複合体硬化体を得た後、実施例１５と同様にして窒素気流中８００℃で揮発分を測定した。
【００８７】
実施例１７〜２９
実施例８と同じレゾール型フェノール樹脂１００質量部に、実施例１と同じネットワークフェニルポリシラン１０質量部を加えて室温で均一混合し、得られた混合物１００質量部に、縮合促進触媒としてＣｏ粉末（実施例１７）、Ｓｎ粉末（実施例１８）、Ｔｉ粉末（実施例１９）、還元鉄粉末（実施例２０）、ＣｏＯ粉末（実施例２１）、Ｃｏ₃Ｏ₄粉末（実施例２２）、Ｃｕ₂Ｏ粉末（実施例２３）、ＺｎＯ粉末（実施例２４）、ＭｇＯ粉末（実施例２５）、ＺｒＯ₂粉末（実施例２６）、ＳｎＯ粉末（実施例２７）、ＺｎＳ粉末（実施例２８）、ＣｕＳ粉末（実施例２９）をそれぞれ３質量部加えて室温で均一混合し、得られた混合物を窒素雰囲気中２５０℃で１時間保持して硬化させた。得られたフェノール樹脂−ポリシラン複合体を約６０メッシュに粉砕し、得られた粉砕物の揮発分を窒素気流中８００℃で測定した。
【００８８】
比較例６
実施例８と同じレゾール型フェノール樹脂を窒素雰囲気中２５０℃で１時間保持して硬化させた。得られたフェノール樹脂の硬化体を約６０メッシュに粉砕し、得られた粉砕物の揮発分を窒素気流中８００℃で測定した。
【００８９】
表３に示す結果から、フェノール樹脂単独の場合には、揮発分の量が多いことが明らかである。
【００９０】
比較例７
実施例８と同じレゾール型フェノール樹脂１００質量部に、２００メッシュ以下のＳｉＯ₂を１０質量部を加え、室温で均一混合した後、該混合物を窒素雰囲気中２５０℃で１時間保持して硬化させた。得られた硬化体を約６０メッシュに粉砕し、得られた粉砕物の揮発分を窒素気流中８００℃で測定した。
【００９１】
表３に示す結果から、ポリシランに代えてＳｉＯ₂を使用する場合には、揮発分の量が多いことがわかる。
【００９２】
比較例８
先行技術文献として挙げた特開昭６１−７７６５３号公報は、バインダーにシリコーン系オリゴマーを配合している。そこで、実施例８と同じレゾール型フェノール樹脂１００質量部にシリコーン系オリゴマー（米国Owens Illinois社製、Glass Resin GR950）を１０質量部を加え、室温で均一混合した後、該混合物を窒素雰囲気中２５０℃で１時間保持して硬化させた。得られた組成物を約６０メッシュに粉砕し、得られた粉砕物の揮発分を窒素気流中８００℃で測定した。
【００９３】
表３に示す結果から、ポリシランに代えてシリコーン系オリゴマーを使用した場合には、揮発分の量が多いことがわかる。
【００９４】
【表３】

【００９５】
実施例３０〜３３
表４に示す割合（質量部）で粉末フェノ−ル樹脂（鐘紡（株）製、品番“Ｓ−８９５”）にポリシラン（実施例１と同じもの）を混合するか、或いはフェノール樹脂とポリシランにＭｇＯ、ＺｒＯ₂またはＣｕ₂Ｏを混合して、複合バインダ−Ａ（実施例３０）、Ｂ（実施例３１）、Ｃ（実施例３２）およびＤ（実施例３３）をそれぞれ製造した。
【００９６】
より詳しくは、ブレンダ−に粉末フェノ−ル樹脂およびポリシランを入れ、１分間混合後、そのまま５分間混合するか（複合バインダ−Ａ）、或いはブレンダ−に粉末フェノ−ル樹脂およびポリシランを入れ、１分間混合した後、さらにＭｇＯ、ＺｒＯ₂またはＣｕ₂Ｏを添加し、５分間混合して（複合バインダ−Ｂ、ＣおよびＤ）、複合バインダ−を得た。得られた各複合バインダ−と、炭素繊維、アラミド繊維、カシューダスト、黒鉛、バライト、ロックウールおよび銅粉とをそれぞれ表５に示す割合（質量部）でロッキングミキサ−で１時間混合し、均一な混合物を得た。
【００９７】
この混合物をそれぞれ成形用金型に入れ、１５０℃、１０ＭＰａの条件で加熱圧縮成形を行った後、得られた成形物を２００℃にて５時間後硬化処理を行い、試料を得た。
【００９８】
得られた試料を、定速式摩擦試験機（摩擦面はＦＣ２５０製、摩擦円盤直径３５０ｍｍ、厚さ１０ｍｍ、試験材の取付け位置は中心から１５０ｍｍの位置、試験片の大きさは長さ２５ｍｍ×幅２５ｍｍ×厚さ６ｍｍ）を用いて、ＪＩＳ Ｄ−４４１１に準じて周速８m/s、面圧１ＭＰａ、温度３００℃における引きずりおよび断続試験の摩擦係数μを測定し、表６に示す結果を得た。
【００９９】
引きずり試験は、試験片を摩擦面に面圧１ＭＰａで押し付けて３０分間行った。なお、最初の１０分間はデータが不安定であるため、除外し、後の２０分間の測定値をデータとした。
【０１００】
断続試験は、試験片を摩擦面に面圧１ＭＰａで２０秒間押しつけた後、荷重を２０秒間解放することを１サイクルとして、６０サイクルの試験を行った。なお、最初の１０サイクルはデータが不安定であるため、除外し、後の５０サイクルの測定値をデータとした。
【０１０１】
比較例９
複合バインダ−の代わりに粉末フェノ−ル樹脂を用いる以外は実施例３０〜３３と同様にして試料を製造し（表５参照）、その摩擦特性を調べ、結果を表６に示した。
【０１０２】
比較例１０〜１３
ポリシランを使用することなく、粉末フェノ−ル樹脂に対し表４に示す割合でＭｇＯまたはＺｒＯ₂を添加して作った複合バインダ−Ｅ、Ｆ、Ｇ、Ｈを用いる以外は実施例３０〜３３と同様にして試料を製造し、その摩擦特性を調べ、表６に結果を示した。
【０１０３】
表６に示す実施例３０〜３３と比較例１０〜１３の値を比較すると、実施例ではバラツキＲ１及びＲ２が小さいことがわかる。フェード現象は、Ｒ１およびＲ２が小さいほど起こりにくいことから、本発明のバインダー組成物を使用して得られる摩擦材は、耐フェード性に優れていることが明らかである。
【０１０４】
【表４】

【０１０５】
【表５】

【０１０６】
【表６】

【０１０７】
注：Ｒ１＝μｍａｘ−μｍｉｎ
Ｒ２＝断続の平均μ−引きずりの平均μ[0001]
[Industrial application fields]
The present invention relates to a binder composition for a friction material and a friction material. When the binder composition according to the present invention is used for production of friction materials in brakes and clutches for various vehicles such as automobiles, the fade resistance and wear resistance of the friction materials can be greatly improved.
[0002]
[Prior art and its problems]
In recent years, there has been a strong demand for higher performance and downsizing of brakes and clutches in vehicles such as automobiles due to the fact that the output of the engine has increased in recent years, and at the same time the demand for lighter body weight has been increasing. ing.
[0003]
On the other hand, the fade phenomenon in which the friction coefficient decreases during high-temperature operation and the judder phenomenon in which the friction coefficient fluctuates rapidly are long-standing technical problems that are required to be eliminated or reduced in these vehicle parts. JMHerring Jr. (SAE Paper, 670146 (1967)), Inoue et al.'S research report (Tribologist, Vol. 37, No. 6 (1992), p. 493) shows that these components are directly responsible for the fade phenomenon. Examples thereof include gases and tar-like substances that are thermal decomposition products of thermosetting resin cured bodies that are used as binders or friction modifiers.
[0004]
Conventionally, in order to suppress the generation of such gases and tar-like substances, 1) friction materials using naphthol resin as a binder (Japanese Patent Laid-Open No. 4-63387), 2) condensed polycyclic aromatic (pitch) Friction material using a Copna resin crosslinked with a methylene bond as a binder (Japanese Patent Laid-Open No. 1-108492), 3) After forming a mixture of pitch and cyanate ester resin as a binder, at 250 to 650 ° C. Methods such as a semi-carbonized friction material (Japanese Patent Laid-Open No. 5-215164) have been proposed. From a different viewpoint, 4) it has also been proposed to adsorb the generated decomposition products by blending activated carbon with the friction material composition (Japanese Patent Publication No. 59-18429).
[0005]
Further, 5) friction materials using a phenol resin modified with organopolysiloxane as a binder (Japanese Patent Laid-Open No. 61-192711), or 6) friction materials using a binder containing a silicone-based oligomer have been proposed. (Japanese Patent Laid-Open No. 61-77653).
[0006]
However, the binder used in the above 1) and 2) is also an organic substance, and to some extent, it thermally decomposes at a temperature of 400 to 500 ° C., so that a large amount of gas or tar-like substance is inevitable. Although the technique of 3) can suppress the generation of decomposition products, it not only requires a high temperature of 300 to 500 ° C. during production, but also fibrillates such as aramid fibers that are currently the mainstream of reinforcing fibers for friction materials. There is a problem that organic reinforcing fibers that facilitate mixing with other components cannot be used. Further, in the technique 4), activated carbon which is a brittle material is used, so that the strength and durability of the friction material are lowered, and there is also a disadvantage that it is not effective in adsorbing tar-like decomposition products. The technique 5) has a problem that it involves a cost increase due to the modification of the phenol resin. In the technique 6), since a stable silicone-based oligomer is added, the volatilization occurs preferentially over the decomposition of the silicone oligomer, and the effect of suppressing the decomposition of the binder is not sufficiently exhibited.
[0007]
[Problems to be solved by the invention]
The main object of the present invention is to provide a binder for a friction material that can be easily manufactured even with conventional equipment, and that has low volatile content and is excellent in fading resistance, wear resistance, etc. during high temperature operation. is there.
[0008]
[Means for Solving the Problems]
The present inventor has conducted various studies while paying attention to the problems of the prior art as described above, and as a result, a mixture of a thermosetting resin and an organometallic compound, particularly an organosilicon compound having at least a Si-Si bond. When used as a binder, it has been found that a friction material excellent in fade resistance, wear resistance and the like can be obtained, and the present invention has been completed.
[0009]
That is, this invention provides the binder and friction material for the following friction materials;
1. A binder composition for a friction material, comprising a thermosetting resin and an organometallic compound.
[0010]
2. Item 2. The binder composition for a friction material according to Item 1, wherein the organometallic compound is an organosilicon oligomer or organosilicon polymer having at least a Si-Si bond.
[0011]
3. Item 3. The friction material binder composition according to Item 2, wherein the organosilicon oligomer or organosilicon polymer is at least one of phenylethyl polysilane, phenylmethyl polysilane, diphenyl polysilane, and network phenyl polysilane.
[0012]
4). Item 2. The friction material binder composition according to Item 1, wherein the thermosetting resin is at least one of a phenol resin, a furan resin, a polyimide resin, a polyurethane resin, a bismaleimide resin, and a copna resin.
[0013]
5. 5. A friction material comprising the binder composition according to any one of items 1 to 4 as a binder component.
[0014]
Hereinafter, each of the components of the present invention will be described in detail.
[0015]
(I) Thermosetting resin
Examples of the thermosetting resin include novolak type phenolic resin, resol type phenolic resin, furan resin, polyimide resin, polyurethane resin, bismaleimide resin, copna (COPNA) resin, and one or more of these are used. To do.
[0016]
In addition, as the thermosetting resin, a resin obtained by appropriately modifying or modifying these thermosetting resins, for example, a cashew resin, a furan-modified phenol resin, or the like can be used.
[0017]
In addition, you may mix | blend a pitch with the thermosetting resin in the range which does not exceed 30 mass%. The pitch is not particularly limited, but a softening point (R & B method) of about 40 to 350 ° C., more preferably about 60 to 150 ° C., and a carbonization yield of 40% by mass or more is suitable. If the addition amount of the pitch is less than 30% by mass, it hardly affects the thermosetting property of the resin and contributes to an improvement in the carbonization yield of the mixture (that is, a reduction in volatile content at a high temperature).
[0018]
Further, an organosilicon compound may be added to the pitch prior to mixing with the thermosetting resin. In this case, it has become clear that the pitch, which is inherently thermoplastic, can be thermally cured by heating to a temperature of about 250 to 350 ° C. in the presence of an organosilicon compound. The amount of the organosilicon compound added to the pitch is about 1 to 50% by mass based on the pitch. By this addition, an improvement in the carbonization yield of the pitch, that is, an improvement in the carbonization yield of the thermosetting binder composition is recognized.
[0019]
(II) Organometallic compound
In the present invention, an organosilicon compound, an organoboron compound, an organogermanium compound, an organotin compound, an organolead compound, etc. can be used as the organometallic compound. Among these organometallic compounds, organometallic compounds having a radical generation (decomposition) temperature lower than the sublimation or evaporation temperature are more preferable. Examples of the organosilicon compound include those having structures represented by the following formulas (1) and (2).
[0020]
Formula (-SiR ₂ -CR ₂ −) _n (1)
Polycarbosilane represented by
Formula (-SiR ₂ -SiR ₂ −) _n (2)
Polysilane indicated by
However, in said formula (1) and (2), R is the same or different, and is a hydrogen atom, a methyl group, an ethyl group, a phenyl group, etc. Moreover, n is about 3-200 normally, More preferably, it is about 5-100.
[0021]
Moreover, network phenyl polysilane is also mentioned as an organosilicon compound. Here, the network phenyl polysilane refers to a compound represented by the following formula (3) when the phenyl group is φ, and those having no bond are bonded to φ or Si.
[0022]
[Chemical 1]

[0023]
However, in said Formula (3), n is about 3-200 normally, More preferably, it is about 5-100.
[0024]
More specific examples of the organosilicon compounds represented by the formulas (1), (2) and (3) include dimethylpolysilane, diethylpolysilane, phenylethylpolysilane, phenylmethylpolysilane, diphenylpolysilane, and networkphenylpolysilane. Those having a phenyl group such as phenylethyl polysilane, phenylmethyl polysilane, diphenyl polysilane, and network phenyl polysilane are more preferable.
[0025]
Moreover, the compound which substituted a part or all of Si of said formula (1), (2) and (3) by Ge, Sn, or Pb can also be used.
[0026]
(III) Condensation promoting catalyst
When a mixture of a thermosetting resin and an organometallic compound is used as a binder, it is preferable to use a condensation accelerating catalyst in order to promote crosslinking between the thermosetting resin and the organometallic compound. Examples of particularly preferred condensation accelerating catalysts include the following.
[0027]
A amines: N, N-dimethylbenzylamine, N, N-dimethylethyleneamine, 2,4,6-tris (dimethylaminomethyl) phenol and the like.
[0028]
B Lewis acid and protonic acid: cobalt chloride, ferric chloride, zinc chloride, p-toluenesulfonic acid and the like.
[0029]
C metal: cobalt, iron, titanium, tin, copper, zinc and the like.
[0030]
D Metal oxide and metal sulfide: CoO, Co _Three O _Four , Cu ₂ O, FeO, ZnO, MgO, ZrO ₂ SnO, CuS, FeS, ZnS, MoS, etc. If the metal oxide and the metal sulfide are the same metal, the lower the oxidation state, the better (for example, Cu rather than CuO). ₂ O is preferred).
[0031]
When the condensation accelerating catalyst used by mixing with the thermosetting resin and the organometallic compound is a solid, a higher effect is expected as the particle size is smaller. However, since the ultrafine particles are expensive, preferably particles having a size of about 10 μm or less, more preferably particles having a size of about 3 μm or less are used.
[0032]
(IV) Mixing ratio of thermosetting resin and organometallic compound
The blending ratio of the thermosetting resin (when the pitch is blended, treat the complex blended with the pitch as a thermosetting resin) and the organometallic compound is usually 0 to 99.99 to 70% by mass of the latter. About 0.01 to 30% by mass, preferably about 0.05 to 20% by mass with respect to the former 99.95 to 80% by mass, and particularly preferably about 0.1 to 10% by mass with respect to the former 99.90 to 90% by mass. %.
[0033]
The blending ratio of the condensation accelerating catalyst is about 0.01 to 30% by mass, preferably about 0.1 to 15% by mass, more preferably 1 to 10% by mass with respect to the mixture of the organometallic compound and the thermosetting resin. Degree.
[0034]
In the case where a metal, a metal oxide, a metal sulfide, or the like is included in the constituent components of the friction material, the amount of addition of the condensation accelerating catalyst may be reduced. In such a case, the reaction can be effectively accelerated by mixing the thermosetting resin, the organometallic compound and the condensation accelerating catalyst uniformly in advance and then mixing with the constituent components of the friction material.
[0035]
Furthermore, when the heat treatment is performed at a temperature at which the mixture of the thermosetting resin, the organometallic compound, and the condensation accelerating catalyst does not lose its ability as a binder, that is, at a temperature lower than the binder curing reaction start temperature, the reaction proceeds partially. Therefore, the carbonization yield of the binder can be effectively improved.
[0036]
(V) Mixing method of thermosetting resin, organometallic compound and condensation accelerating catalyst
These are mixed by a method in which the powder is mixed when they are solid at room temperature; a method in which these are mixed in a solvent such as chloroform, chlorobenzene, ethanol, etc., and then the solvent is removed. When used, the pitch can be heated and melted and then mixed with an organometallic compound. When the thermosetting resin melts at a temperature of 100 to 230 ° C., an organometallic compound can be mixed therewith. It is also effective to add an organometallic compound during the synthesis of the thermosetting resin. Further, when the thermosetting resin is liquid at room temperature, the organometallic compound can be directly mixed. In these cases, some of the resulting mixture reacts, while the rest exists in an unreacted state.
[0037]
(VI) Friction material manufacturing material
In order to produce friction materials such as brakes and clutches, the above-mentioned binder composition, known friction modifiers, reinforcing fibers and other raw materials are blended, molded according to conventional methods, and heat-treated.
[0038]
The amount of the binder composition used is about 5 to 25% of the total mass of the friction modifier and the reinforcing fibers.
[0039]
As friction modifiers, powders and particles of metals such as copper, brass, bronze, iron, stainless steel, graphite, BaSO _Four , CaCO _Three , MgCO _Three Inorganic powders and particles such as silica, alumina, magnesia, chromium oxide, wollastonite, diatomaceous earth, dolomite, molybdenum sulfide, calcium fluoride can be used.
[0040]
When metal powder and / or particles are used as the friction modifier, the amount added is preferably about 5 to 80% by mass in the friction material material, although depending on the type of metal. It is especially preferable to set it as about mass%.
[0041]
When graphite is used as the friction modifier, the addition amount is preferably about 0.5 to 30% by mass, and about 3 to 20% by mass in the friction material raw material (friction modifier + reinforcing fiber). It is particularly preferable to do this.
[0042]
Moreover, as a friction modifier, organic substances, such as cashew dust and rubber dust, the powder and particle | grains of thermosetting resin hardened | cured material, etc. can be used. A phenol resin, cashew resin, or the like, which is a thermosetting resin containing an organometallic compound, or a cured product of a pitch containing an organometallic compound can also be used. These may be used alone or in combination of two or more depending on the performance required for the friction material.
[0043]
As a cured product of the binder composition of the present invention using a normal phenol resin or cashew resin as a thermosetting resin, the binder composition was cured at about 130 to 300 ° C. (more preferably about 150 to 250 ° C.). Thereafter, it is obtained by post-curing for about 2 to 30 hours at about 200 to 350 ° C. (more preferably about 220 to 300 ° C.). This cured product is preferably used after being pulverized and sized to about 1 μm to 1 mm.
[0044]
Further, a friction modifier may be used in which the organometallic compound of the present invention is added to the pitch and cured by heating. The pitch can be any of petroleum pitch, coal pitch, synthetic pitch made from aromatic hydrocarbons such as naphthalene and acenaphthylene, modified products of these pitches, isotropic pitch and anisotropic Any sex pitch can be used. The blending ratio of the pitch and the organometallic compound is usually about 1-50% by mass with respect to the former 99-50% by mass, more preferably about 5-25% by mass with respect to the former 95-75% by mass. . The both can be mixed by a method of mixing the organometallic compound after heating and melting the pitch, a method of mixing both powders, a method of mixing both in a solvent, and the like. The friction modifier made of such a cured product is obtained by curing a composition composed of pitch and an organometallic compound at about 200 to 450 ° C. (more preferably about 250 to 400 ° C.), and then at about 250 to 450 ° C. It can be obtained by post-curing for about 2 to 30 hours. Such a cured product is also preferably used after being pulverized and sized to about 1 μm to 1 mm. As a friction modifier, such a cured product reduces the generation rate of gas, tar, etc., and improves fade resistance, compared with a phenol resin cured product, cashew resin cured product, and the like that are usually used.
[0045]
When an organic substance such as cashew dust, rubber dust, or a cured material of the binder composition of the present invention is used as the friction modifier, the amount added is 1 to 30% by mass in the friction material raw material (friction modifier + reinforcing fiber). The amount is preferably about 3 to 10% by mass.
[0046]
The particle size of the friction modifier is not particularly limited, and can be determined as appropriate according to the characteristics required of the friction material. For example, if a metal is used, it is selected from a particle size range of about 10 μm to 5 mm, if an inorganic substance is used, about 1 μm to 1 mm, and if an organic substance is used, it is selected from a particle size range of about 1 μm to 1 mm. good.
[0047]
As reinforcing fibers, metal fibers such as copper, brass, iron, and stainless steel, carbon fibers, rock wool, asbestos, ceramic fibers, inorganic fibers such as glass fibers, and organic fibers such as aramid fibers may be used in combination. it can. These fibers exhibit not only a reinforcing effect but also an effect of increasing the friction coefficient.
[0048]
The mixing method of the friction material raw material is not particularly limited, and a dry mixing method, a method of granulating the raw material using a small amount of a binder, a wet mixing method, a wet papermaking method and the like can be employed.
[0049]
(VII) Molding and curing of friction material material
The raw material mixture is not particularly limited. For example, using a hot press, the molding temperature is about 150 to 400 ° C., preferably about 180 to 300 ° C., and the molding pressure is about 1 to 50 Mpa for 1 to 10 minutes. Perform under the condition of degree. In the molding process, it is preferable to repeat the operation of clamping and opening about 2 to 6 times in order to degas appropriately. It is also preferable to perform preheating with a high frequency, microwave, or the like before molding.
[0050]
After molding, post-curing is performed by heat treatment at about 200 to 300 ° C. in air for about 2 to 30 hours. Of course, conventional high-temperature heat treatment such as scorch treatment at about 500 to 600 ° C. is also effective.
[0051]
【The invention's effect】
The binder composition of the present invention in which an organometallic compound is blended is thermally decomposed in a temperature range of 490 to 800 ° C. in a nitrogen atmosphere or in air, as compared with a binder composition in which an organometallic compound is not blended. The generation of volatile matter due to is significantly reduced. Therefore, in the friction material using such a binder composition, the organometallic compound mixed or reacted with the thermosetting resin generates polyradicals due to frictional heat at the time of braking. Since the volatile component is cross-linked to be polymerized and, for example, Si—C bonds are introduced, not only the fading property of the friction material is improved, but also the heat resistance and wear resistance are greatly improved.
[0052]
【Example】
Examples and Comparative Examples are shown below to further clarify the features of the present invention.
[0053]
In addition, the measurement of the volatile matter in an Example and a comparative example was performed as follows.
[0054]
TG-DTA measurement: Using “TGA50” manufactured by Shimadzu Corporation, 10 mg of a sample is precisely weighed in a platinum sample dish, and the temperature is increased from room temperature to 490 ° C. at a temperature increase rate of 10 ° C./min in a nitrogen flow of 50 ml / min. The temperature was raised to 800 ° C., and the mass loss (%) during that time was measured. Further, when air was used instead of nitrogen, it was performed at the same flow rate as nitrogen.
[0055]
Example 1
To 100 parts by mass of novolak type phenolic resin (manufactured by Cashew Co., Ltd., product number “NR-2235”, containing 10% hexamine-based curing agent), network phenyl polysilane (weight average molecular weight MW 6184, dispersity MW / MN = 2.27) 5 parts by mass of decomposition temperature 365 ° C., manufactured by Osaka Gas Co., Ltd.), uniformly mixed in a powder state, cured at 170 ° C. for 20 minutes in air, and further post-cured at 200 ° C. for 6 hours in air. .
[0056]
The obtained phenol resin-polysilane composite was pulverized to about 60 mesh, and the volatile content of the pulverized product was measured at 490 ° C. and 800 ° C. in a nitrogen stream.
[0057]
The results of this example are shown in Table 1 below together with the results of Examples 2 to 7 and Comparative Examples 1 to 4.
[0058]
Example 2
A pulverized product of a phenol resin-polysilane complex was prepared in the same manner as in Example 1 except that the amount of network phenyl polysilane added was 3 parts by mass. The volatile matter of the pulverized product was 490 ° C and 800 ° C in a nitrogen stream. It was measured.
[0059]
Example 3
Example 1 was used except that 5 parts by mass of diphenylpolysilane (weight average molecular weight MW1756, dispersity MW / MN = 4.69, decomposition temperature 373 ° C., manufactured by Osaka Gas Co., Ltd.) was used in place of network phenylpolysilane. Then, a pulverized product of the phenol resin-polysilane complex was prepared, and the volatile content of the pulverized product was measured at 490 ° C. and 800 ° C. in a nitrogen stream.
[0060]
Example 4
A pulverized product of a phenol resin-polysilane complex in the same manner as in Example 1 except that 100 parts by mass of a resol type phenol resin (manufactured by Kanebo Co., Ltd., product number “S-899”) was used instead of the novolak type phenol resin. The volatile matter of the pulverized product was measured at 490 ° C. and 800 ° C. in a nitrogen stream.
[0061]
Example 5
A pulverized product of a phenol resin-polysilane complex was obtained in the same manner as in Example 1 except that 100 parts by mass of a resol type phenol resin was used in place of the novolac type phenol resin and the amount of network phenyl polysilane used was 10 parts by mass. The volatile content of the pulverized product was measured at 490 ° C. and 800 ° C. in a nitrogen stream.
[0062]
Example 6
A pulverized product of a phenol resin-polysilane complex was prepared in the same manner as in Example 1 except that the amount of network phenyl polysilane used was 25 parts by mass. The volatile content of the pulverized product was 490 ° C and 800 ° C in an air stream. Measured with
[0063]
Example 7
(1) Preparation of polysilane / pitch composite A
100 parts by mass of straight coal tar pitch (softening point 84.2 ° C., quinoline insoluble content 5.4% by mass, benzene insoluble content 22.7% by mass) is blended with 10 parts by mass of diphenylpolysilane as in Example 3, and in an autoclave. The polysilane / pitch composite A was prepared by thermal copolymerization at 350 ° C. for 3 hours under a nitrogen atmosphere.
[0064]
(2) Preparation of polysilane / phenol resin composite B
10 parts by mass of the same diphenyl polysilane as in Example 3 was blended with 100 parts by mass of the same novolak type phenolic resin as in Example 1, and uniformly mixed in a powder state to prepare a polysilane / phenol resin composite B.
[0065]
(3) Preparation of complex C
3 parts by mass of the complex A obtained above and 7 parts by mass of the complex B were uniformly mixed in a powder state and then cured in air at 240 ° C. for 12 hours to prepare a complex C.
[0066]
(4) Measurement of volatile content of complex C
The composite C obtained above was pulverized, and the volatile content of the pulverized product obtained was measured at 490 ° C. and 800 ° C. in a nitrogen stream in the same manner as in Example 1.
[0067]
Comparative Example 1
Without blending the network phenyl polysilane, the novolak type phenol resin was cured by heating at 170 ° C. for 20 minutes in air according to Example 1, and further post-cured at 200 ° C. for 6 hours in air. The obtained cured product was pulverized to about 60 mesh, and the volatile content of the obtained pulverized product was measured at 490 ° C. and 800 ° C. in a nitrogen stream.
[0068]
Comparative Example 2
Without blending network phenyl polysilane, the same resol type phenol resin as in Example 4 was cured by heating at 170 ° C. for 20 minutes in air, and further post-cured at 200 ° C. for 6 hours in air. The obtained cured product was pulverized to about 60 mesh, and the volatile content of the obtained pulverized product was measured at 490 ° C. and 800 ° C. in a nitrogen stream.
[0069]
Comparative Example 3
Without blending the network phenyl polysilane, the novolac type phenol resin was cured by heating at 170 ° C. for 20 minutes in the air according to Example 6, and further post-cured at 200 ° C. for 6 hours in the air. The obtained cured product was pulverized to about 60 mesh, and the volatile content of the pulverized product obtained was measured at 490 ° C and 800 ° C in an air stream.
[0070]
Comparative Example 4
100 parts by mass of the straight coal tar pitch of Example 7 was heated in an autoclave at 350 ° C. for 3 hours in a nitrogen atmosphere. 3 parts by mass of this and 7 parts by mass of novolac-type phenol resin powder were uniformly mixed in a powder state at room temperature, and then cured in air at 240 ° C. for 12 hours to prepare a pitch / phenol resin composite. The obtained composite was pulverized to about 60 mesh, and the volatile content was measured at 490 ° C. and 800 ° C. in a nitrogen stream.
[0071]
[Table 1]

[0072]
From the results shown in Table 1, it is clear that according to the present invention, the introduction of Si-C bonds improves the carbonization yield of the binder composition and greatly improves the heat resistance of the friction material.
[0073]
For example, if Example 1 (combined use of novolac-type phenolic resin + network phenyl polysilane) and Comparative Example 1 (use of novolac-type phenolic resin alone) are compared, the amount of volatile components generated at high temperatures is significantly reduced in the former. Yes.
[0074]
Further, when Example 4 (combination of resol type phenol resin + network phenyl polysilane) and Comparative Example 2 (use of resol type phenol resin alone) are compared, the amount of volatile matter generated at high temperature is significantly reduced in the former case. .
[0075]
Furthermore, when Example 6 (combined use of novolac-type phenolic resin + network phenyl polysilane) and Comparative Example 3 (use of novolac-type phenolic resin alone) are compared, the volatile matter (oxidation consumption amount) in high-temperature air is marked in the former. is decreasing.
[0076]
Furthermore, when Example 7 (combination of pitch + diphenylpolysilane + novolac type phenolic resin) and Comparative Example 4 (combination of pitch + novolac type phenolic resin) are compared, the former has a volatile content at a high temperature in a nitrogen stream. It is clear that the amount generated is significantly reduced.
[0077]
Example 8
100 parts by mass of a resol-type phenolic resin (manufactured by Kanebo Co., Ltd., product number “S-895”) and 10 parts by mass of the same network phenylpolysilane as in Example 1 are uniformly mixed in a powder state, and 100 parts by mass of the resulting mixture is mixed. 100 parts by mass of ethanol was added, and the mixture was stirred and mixed at room temperature. The solvent was removed with an evaporator, and further dried in a vacuum dryer at 40 ° C. for 4 hours. The obtained dried product was cured by being held at 250 ° C. for 1 hour in a nitrogen atmosphere. The obtained phenol resin-polysilane complex was pulverized to about 60 mesh, and the volatile content of the obtained pulverized product was measured at 800 ° C. in a nitrogen stream.
[0078]
The results of this example are shown in Table 2 together with the results of Examples 9 to 14 and Comparative Example 5.
[0079]
Example 9
10 parts by mass of the same network phenylpolysilane as in Example 1 was uniformly mixed with 100 parts by mass of the same resol type phenolic resin as in Example 8 in a powder state, and ZnCl as a condensation accelerating catalyst was added to 100 parts by mass of the resulting mixture. ₂ 3 parts by mass and 100 parts by mass of ethanol were added, and the mixture was stirred and mixed at room temperature. The solvent was removed with an evaporator, and further dried at 40 ° C. for 4 hours in a vacuum dryer. The obtained dried product was cured by being held at 250 ° C. for 1 hour in a nitrogen atmosphere. The obtained phenol resin-polysilane complex was pulverized to about 60 mesh, and the volatile content of the obtained pulverized product was measured at 800 ° C. in a nitrogen stream.
[0080]
Examples 10-14
ZnCl of Example 9 ₂ Instead of CoCl ₂ ・ 6H ₂ O (Example 10), FeCl _Three ・ 6H ₂ O (Example 11), p-toluenesulfonic acid · 1H ₂ Except for using 3 parts by mass of O (Example 12), 2,4,6-tris (N, N-dimethylaminomethyl) phenol (Example 13) and N, N-dimethylbenzylamine (Example 14). Measured the volatile content of the pulverized material prepared in the same manner as in Example 9 at 800 ° C. in a nitrogen stream.
[0081]
Comparative Example 5
100 parts by mass of ethanol was added to 100 parts by mass of the same resol type phenolic resin as in Example 8, stirred, and then dried and cured under the same conditions as in Example 8.
[0082]
The obtained dried product was cured by being held at 250 ° C. for 1 hour in a nitrogen atmosphere. The obtained phenol resin-polysilane composite was pulverized to about 60 mesh, and the volatile content of the pulverized product was measured at 800 ° C. in a nitrogen stream.
[0083]
[Table 2]

[0084]
Example 15
10 parts by mass of the same network phenylpolysilane as in Example 1 is added to 100 parts by mass of the same resol type phenolic resin as in Example 8, and uniformly mixed at room temperature. The resulting mixture is held at 250 ° C. for 1 hour in a nitrogen atmosphere. Cured. The obtained phenol resin-polysilane composite was pulverized to about 60 mesh, and the volatile content of the pulverized product was measured at 800 ° C. in a nitrogen stream.
[0085]
The results of Examples and Examples 16 to 29 and Comparative Examples 6 to 8 are also shown in Table 3 below.
[0086]
Example 16
100 parts by mass of the same resol type phenolic resin as in Example 8, and 10 parts by mass of network phenyl polygermane (manufactured by Osaka Gas Co., Ltd., weight average molecular weight MW 885, dispersity MW / MN = 2.3) instead of network phenyl polysilane Was used under the same conditions as in Example 15 to obtain a cured phenol resin-polygerman complex, and then the volatile content was measured at 800 ° C. in a nitrogen stream in the same manner as in Example 15. .
[0087]
Examples 17-29
10 parts by mass of the same network phenyl polysilane as in Example 1 was added to 100 parts by mass of the same resol type phenolic resin as in Example 8, and uniformly mixed at room temperature. Co powder (as a condensation accelerating catalyst) was added to 100 parts by mass of the resulting mixture. Example 17), Sn powder (Example 18), Ti powder (Example 19), reduced iron powder (Example 20), CoO powder (Example 21), Co _Three O _Four Powder (Example 22), Cu ₂ O powder (Example 23), ZnO powder (Example 24), MgO powder (Example 25), ZrO ₂ 3 parts by mass of powder (Example 26), SnO powder (Example 27), ZnS powder (Example 28), and CuS powder (Example 29) were added and mixed uniformly at room temperature, and the resulting mixture was nitrogen atmosphere It was cured by holding at 250 ° C. for 1 hour. The obtained phenol resin-polysilane complex was pulverized to about 60 mesh, and the volatile content of the obtained pulverized product was measured at 800 ° C. in a nitrogen stream.
[0088]
Comparative Example 6
The same resol type phenolic resin as in Example 8 was cured by being held at 250 ° C. for 1 hour in a nitrogen atmosphere. The obtained cured phenol resin was pulverized to about 60 mesh, and the volatile content of the pulverized product was measured at 800 ° C. in a nitrogen stream.
[0089]
From the results shown in Table 3, it is clear that the amount of volatile matter is large in the case of the phenol resin alone.
[0090]
Comparative Example 7
In 100 parts by mass of the same resol type phenolic resin as in Example 8, 200 mesh or less of SiO ₂ 10 parts by mass was added and mixed uniformly at room temperature, and then the mixture was kept at 250 ° C. for 1 hour in a nitrogen atmosphere to be cured. The obtained cured product was pulverized to about 60 mesh, and the volatile content of the obtained pulverized product was measured at 800 ° C. in a nitrogen stream.
[0091]
From the results shown in Table 3, instead of polysilane, SiO ₂ It can be seen that the amount of volatile matter is large when using.
[0092]
Comparative Example 8
In Japanese Patent Application Laid-Open No. 61-77653 cited as a prior art document, a silicone-based oligomer is blended in a binder. Thus, 10 parts by mass of a silicone oligomer (Glass Resin GR950, manufactured by Owens Illinois, USA) is added to 100 parts by mass of the same resol type phenolic resin as in Example 8, and the mixture is uniformly mixed at room temperature. It was kept at 1 ° C. for 1 hour to be cured. The obtained composition was ground to about 60 mesh, and the volatile content of the obtained ground product was measured at 800 ° C. in a nitrogen stream.
[0093]
From the results shown in Table 3, it can be seen that when a silicone-based oligomer is used instead of polysilane, the amount of volatile components is large.
[0094]
[Table 3]

[0095]
Examples 30-33
Polysilane (same as in Example 1) is mixed with powdered phenol resin (product number “S-895” manufactured by Kanebo Co., Ltd.) in the ratio (parts by mass) shown in Table 4, or the phenol resin and polysilane are mixed. MgO, ZrO ₂ Or Cu ₂ O was mixed to produce composite binders A (Example 30), B (Example 31), C (Example 32), and D (Example 33).
[0096]
More specifically, powder phenolic resin and polysilane are put into a blender and mixed for 1 minute and then mixed for 5 minutes as they are (composite binder A), or powdered phenolic resin and polysilane are put into a blender. After mixing for a minute, further MgO, ZrO ₂ Or Cu ₂ O was added and mixed for 5 minutes (composite binders B, C and D) to obtain a composite binder. Each of the obtained composite binders, carbon fiber, aramid fiber, cashew dust, graphite, barite, rock wool and copper powder were mixed for 1 hour with a rocking mixer in the proportions (parts by mass) shown in Table 5, and uniform. A good mixture was obtained.
[0097]
Each mixture was put into a molding die and subjected to heat compression molding at 150 ° C. and 10 MPa, and then the obtained molded product was post-cured at 200 ° C. for 5 hours to obtain a sample.
[0098]
The obtained sample was subjected to a constant speed friction tester (friction surface made of FC250, friction disk diameter 350 mm, thickness 10 mm, test material mounting position 150 mm from the center, test piece size 25 mm length × Using a width 25 mm × thickness 6 mm), a drag at a peripheral speed of 8 m / s, a surface pressure of 1 MPa, and a temperature of 300 ° C. and a friction coefficient μ of an intermittent test were measured according to JIS D-4411, and the results shown in Table 6 were obtained. Obtained.
[0099]
The drag test was performed for 30 minutes by pressing the test piece against the friction surface at a surface pressure of 1 MPa. The data for the first 10 minutes was unstable and therefore excluded, and the measured values for the subsequent 20 minutes were used as data.
[0100]
In the intermittent test, the test piece was pressed against the friction surface at a surface pressure of 1 MPa for 20 seconds, and then the load was released for 20 seconds. The first 10 cycles were excluded because the data was unstable, and the measured values for the subsequent 50 cycles were used as data.
[0101]
Comparative Example 9
Samples were produced in the same manner as in Examples 30 to 33 except that powdered phenol resin was used instead of the composite binder (see Table 5), the friction characteristics thereof were examined, and the results are shown in Table 6.
[0102]
Comparative Examples 10-13
Without using polysilane, MgO or ZrO in the proportions shown in Table 4 with respect to the powdered phenolic resin ₂ Samples were produced in the same manner as in Examples 30 to 33 except that composite binders E, F, G, and H prepared by adding N were used, their friction characteristics were examined, and the results are shown in Table 6.
[0103]
Comparing the values of Examples 30 to 33 and Comparative Examples 10 to 13 shown in Table 6, it can be seen that variations R1 and R2 are small in the examples. Since the fade phenomenon is less likely to occur as R1 and R2 are smaller, it is clear that the friction material obtained using the binder composition of the present invention is excellent in fade resistance.
[0104]
[Table 4]

[0105]
[Table 5]

[0106]
[Table 6]

[0107]
Note: R1 = μmax−μmin
R2 = intermittent mean μ−drag average μ

Claims (4)

A binder composition for a friction material, comprising a thermosetting resin and an organosilicon oligomer or organosilicon polymer having at least a Si-Si bond .   The binder composition for a friction material according to claim 1, wherein the organosilicon oligomer or the organosilicon polymer is at least one of phenylethyl polysilane, phenylmethyl polysilane, diphenyl polysilane, and network phenyl polysilane.   The binder composition for a friction material according to claim 1, wherein the thermosetting resin is at least one of a phenol resin, a furan resin, a polyimide resin, a polyurethane resin, a bismaleimide resin, and a copna resin. Friction material and the binder component of the binder composition according to any one of claims 1 to 3.