JP3559874B2 - Urethane bonding materials - Google Patents

Description

【００１８】
上記粗製ＴＢＳの有機溶媒溶液の添加は１回で完了してもよいし、数回に分けて行ってもよいし、或いは連続的に行ってもよい。
【００１９】
本発明において、プレポリマーはポリオールと過剰のポリイソシアネートとを重合させることにより製造される。
【００２０】
本発明で用いられるポリオールとしては、分子末端に２個以上の水酸基を有する多価アルコール類である限り、従来公知のものを広く使用できる。具体的にはポリエーテルポリオールとポリエステルポリオールのような分子内の化学結合で分類すると、以下のようなポリオールを例示できる。
【００２１】
即ち、分子内にエーテル結合を持つポリエーテルポリオールとしては、ポリオキシアルキレンジオール（具体的にはポリオキシエチレングリコール、ポリオキシプロピレングリコール、ポリオキシブチレングリコール等やこれらの共重合体）、ポリオキシアルキレントリオール（具体的にはエチレンオキシド、プロピレンオキシド、ブチレンオキシド、スチレンオキシド等とグリセリン、トリメチロールプロパン等を付加重合させたもの）等のポリオキシアルキレンポリオール、テトラヒドロフランの開環重合により得られるポリオキシテトラメチレングリコール等の他、ビスフェノール、シュガー類、エチレンジアミン等のアミン類を出発原料としてエチレンオキシド又はプロピレンオキシドを付加させたジオール、トリオール等を挙げることができる。
【００２２】
分子内にエステル結合を持つポリエステルポリオールとしては、エステル結合を繰返し単位として有する末端に水酸基を有する化合物である限り、従来公知のものを広く使用できる。具体的には、多価カルボン酸（主としてアジピン酸やフタル酸）と多価アルコール（具体的にはグリコール、トリオール等）との脱水縮合によって得られる縮合系ポリエステルポリオール；ε−カプロラクトンの開環重合により得られるラクトン系ポリエステルポリオール；ポリオールのホスゲン化又はジフェニレンカーボネートによるエステル交換反応により得られるポリカーボネートジオール；ポリカルボン酸無水物とジエポキサイドとの重付加反応によるポリエステルポリオール；分子内部にウレタン基等を導入したようなウレタン変性ポリエステルポリオールを挙げることができる。
【００２３】
本発明では、これらポリオールは１種単独で又は２種以上混合して使用される。
【００２４】
一方、本発明で用いられるポリイソシアネートは、１分子中に２個以上のイソシアネート基を有する化合物、所謂多官能イソシアネート化合物である。斯かる多官能イソシアネート化合物としては、例えば２，４−トルエンジイソシアネート、２，６−トルエンジイソシアネートとその異性体混合物、４，４’−ジフェニルメタンジイソシアネート（以下「４，４’−ＭＤＩ」という）、４，４’−ＭＤＩと２，４’−ジフェニルメタンジイソシアネート（以下「２，４’−ＭＤＩ」という）との混合物（商品名：ルプラネートＭＩ、ビーエーエスエフジャパン製）、カルボジイミド変性ジフェニルメタンジイソシアネート、粗製ＭＤＩ、ヘキサメチレンジイソシアネート（以下「ＨＭＤＩ」という）、キシレンジイソシアネート（以下「ＸＤＩ」という）、メタキシリレンジイソシアネート、１，５−ナフタレンジイソシアネート、水素化ジフェニルメタンジイソシアネート、水素化トルエンジイソシアネート、水素化キシレンジイソシアネート、イソホロンジイソシアネート等のイソシアネート化合物；スミジュールＮ（住友バイエルウレタン社製）等のビュレットポリイソシアネート化合物；デスモジュールＩＬ、ＨＬ（バイエルＡ．Ｇ．社製）、コロネートＥＨ（日本ポリウレタン工業株式会社製）等のイソシアネート環を有するポリイソシアネート化合物；スミジュールＬ（住友バイエルウレタン社製）、コロネートＨＬ（日本ポリウレタン工業株式会社製）等のアダクトポリイソシアネート環を有するポリイソシアネート化合物等を挙げることができる。
【００２５】
本発明では、これらポリイソシアネートは１種単独で又は２種以上混合して使用される。
【００２６】
プレポリマーを合成するに当っては、特に制限がなく、従来公知の方法で製造すればよい。過剰のポリイソシアネートとはポリオールのＯＨ基当量よりイソシアネート当量が過剰であることを意味し、その当量関係をＮＣＯ／ＯＨ比で表わすことができる。即ち、理論的にはＮＣＯ／ＯＨ比を１以上とすればイソシアネート末端となり得るが、本発明ではプレポリマーが高温では液状、室温付近ではゼリー状の形態を採り得るようにする観点から、通常ＮＣＯ／ＯＨ比が１．５以上が好ましい。ＮＣＯ／ＯＨ比の上限は特に限定されるものではないが、ＮＣＯ／ＯＨ比１０以下がより好ましい。殊に液状で低粘度のプレポリマーに導くためには、ポリオールの種類、官能基数、分子量等を考慮すると共にＮＣＯ／ＯＨ比を２〜１０程度に調節することが特に好ましい。重合温度及び重合時間も特に制限されないが、通常水分の影響を避けるために窒素気流下でポリオールとポリイソシアネートとを混合後、５０〜１００℃にて３〜８時間反応させるのがよい。反応前、反応途中及び反応終了後、有機金属塩系ウレタン重合触媒、安定剤、水分補促剤、重合調節剤等を適量随時添加しても差支えない。
【００２７】
本発明の方法は、上記重合反応の開始時又は重合反応の途中に、粗製ＴＢＳの有機溶媒溶液を反応系内に存在させて、ポリオールの水酸基と共に副生物の有する水酸基を５０〜８０℃の反応温度領域で過剰のポリイソシアネートで消失させることを特徴とする。
【００２８】
従って重合を開始する時点で又は反応途中の段階で、粗製ＴＢＳの有機溶媒溶液（以下「Ｃ−ＴＢＳ溶液」と略記する）を配合しなければ、未反応の活性水素を有する副生物のため、イソシアネート含有量の固定はできず、その結果長期間安定なゼリー状ウレタン樹脂は得られず、経時的にゲル化ポリマーを形成して熱不可逆性ゲルとなってしまう。即ち、イソシアネート含有量が経時的に消失すれば、このゼリー状ウレタンの特質である優れた反応性は損われるので、本発明の目的は適えられない。
【００２９】
本発明では、ポリオールに予めＣ−ＴＢＳ溶液を加えて、ポリイソシアネートを混合後、通常のウレタン重合温度である５０〜１００℃にて３〜８時間重合反応を行うことも可能であるが、活性水素を有する副生物が、副反応を生じやすく、イソシアネート含有率を低下させ、且つ得られるゼリー状ウレタン樹脂の黄変化傾向を生じるため、反応率が２０〜９５％の時点でＣ−ＴＢＳ溶液を反応系内に存在させることが好ましい。本発明では、反応率が３０〜９０％に至れば、Ｃ−ＴＢＳ溶液を添加した上で、引続きジブチル錫ジラウレート等の有機金属系ウレタン重合触媒をポリオール１００重量部当り０．０００５〜０．０２重量部添加して未反応水酸基等の活性水素とのウレタン化反応を促進させる方法を採用するのが特に好ましい。
【００３０】
更にこのように反応率３０〜９０％にて粗製ＴＢＳを配合すれば、トルエンジイソシアネートのような有害な未反応イソシアネートモノマーの有効な低減化手段となり、人体、環境への悪影響を軽減化できる。
【００３１】
ゼリー状ウレタンプレポリマーを得るためには、イソシアネート末端のウレタンプレポリマー１００重量部当り、粗製ＴＢＳ０．１〜１０重量部を有機溶媒０．３〜３０重量部で溶解した溶液（Ｃ−ＴＢＳ溶液）を添加するのが望ましい。本発明でいうゼリー状とは、保形性を保ったものであって、具体的には寒天、ゼリーを固めたような半固形状態や、市販されている事務用スチックのりのような弾力性のある固形状のものをいう。また、このゼリー状態は、低温域での急激な粘度上昇が認められる通常の液状ウレタンのような、ゲル硬度の温度依存性が少ない。
【００３２】
従って粗製ＴＢＳの添加量が０．１重量部を下回ると、ウレタンプレポリマーが液状を呈する傾向となり、逆に１０重量部より多くなると、イソシアネート含有率の経時的消失が激しくなって、安定性が得られ難くなり、しかも得られたゲル化物も弾力を失った硬くて脆いゲル化物を与える傾向となると共に、経時的に粗製ＴＢＳの析出を招きゲル化体としての品質を損ねてしまう傾向となるので、いずれも好ましくない。本発明で意図するポマードのようなチクソトロピック粘体から半固形状態、弾力性のある固形状態を得るための好ましい範囲は、プレポリマー１００重量部当り粗製ＴＢＳ０．５〜７重量部（より好ましくは０．６〜３重量部）、上記有機溶媒１．５〜２０重量部（より好ましくは１．８〜９重量部）である。
【００３３】
本発明のゼリー状プレポリマーには、通常プレポリマーに配合される各種添加剤を配合することができる。例えば、無水シリカ、アマイドワックスのような増粘剤，トルエンスルホニルイソシアネートのような水分キャッチャー剤、可塑剤、有機溶剤、粘着性付与樹脂、他のポリマー類、安定剤等を挙げることができる。
【００３４】
一方、本発明においてＢ剤はイソシアネート基と反応し得る活性水素を有する化合物を含有するペースト状組成物である。斯かるペースト状組成物としては、従来この種２液型ウレタン系接合材においてＢ剤として用いられているものを広く使用できる。具体的には分子内に水酸基、アミノ基、カルボキシル基等の活性水素、好ましくは水酸基を有する化合物に無機質充填材、増粘剤、各種添加剤等を配合したものであって、通常その性状は流動性の乏しい高粘度ペースト状を有するものである。活性水素化合物としては、本発明のプレポリマーの合成の出発原料に用いるポリオール類、そのポリオール類にアミン系化合物、カルボン酸類のような他の活性水素化合物と配合したもの等、従来のウレタンプレポリマー（Ａ剤）に反応し得るＢ剤に使用される化合物を広く用いることができる。
【００３５】
Ａ剤とＢ剤とはその当量比を考慮して配合すればよく、その配合比は、Ａ剤として従来のプレポリマーを使用する場合となんら異なるところはない。即ちゼリー状プレポリマーのイソシアネート基含有率を基本として、Ｂ剤の当量比を選択すればよい。
【００３６】
例えばＢ剤として水酸基を有するポリオールを含有するペーストを用いる場合、その水酸基価とＡ剤のイソシアネート基の当量比を通常用いられるＮＣＯ／ＯＨの比率を通常１〜３、好ましくは１〜１．５の範囲に設定すればよい。要は、一般的な液状プレポリマーと同様に、ゼリー状プレポリマーのイソシアネート基含有率を考慮して、目的に応じて公知の方法で当量比を決定すればよい。
【００３７】
【発明の効果】
本発明の接合材において、Ａ剤であるゼリー状プレポリマーは、完全な保形性を有するため、消防法危険物第４類を代表とする各種法規制の厳しい危険・有害度の高い可燃性液体とはならず、可燃性固体となるため、貯蔵時又は輸送時の漏損、漏洩事故を防止できる。またこの安全性のため、保管容器も産業廃棄物問題となりがちな金属容器を使用しなくてもよく、環境に負荷を与えることの少ない加工紙製容器等を自由に選択できる。
【００３８】
使用時にＡ剤をＢ剤に配合する場合、Ａ剤とＢ剤との粘度差が少なく、しかも撹拌機による強い剪断力により容易に液状化するため混合性に優れ、混合時間が少なくて済む。また撹拌開始時に保形性を保つために、液状に認められるような飛び散りがない。従って本発明の接合材は混合作業性が大幅に改良されたものである。
【００３９】
更にゼリー状プレポリマーを製造する際に、活性水素化合物を含有するトリベンジリデンソルビトールを反応開始又は反応途中で反応系内に存在させるので、有害な残存イソシアネートモノマーが消費され、人体に有害な残存イソシアネート化合物の削減対策となる。
【００４０】
本発明接合材のＡ剤であるゼリー状プレポリマーは、一旦ゲル化してしまえば、液状プレポリマーに見られる低温域での粘度上昇がなく、ゲル硬度が温度の影響を受け難いという特徴をも有している。
【００４１】
【実施例】
以下本発明の実施例を挙げて本発明をより一層明らかにするが、本発明はこれら実施例に限定されるものではない。尚、以下において、単に「部」及び「％」とあるのは特記しない限り「重量部」及び「重量％」を意味する。
【００４２】
参考例１
温度計、還流管及び撹拌機を備えた１リットルの三ツ口フラスコにＮ−メチル−２−ピロリドン４００部を仕込み、工業的トリベンジリデンソルビトール（活性水素化合物の含有率３％、水分１％、微黄色粉末、商品名：ゲルオールＴ、新日本理化社製）１００部を配合し、８０℃にて３０分間溶解させて、黄色透明溶液を得た。溶液内の水分を除去するため、水分吸着剤モルキュラーシーブ果粒を適量配合して２０％の活性水素化合物を含有するトリベンジリデンソルビトールのＮ−メチル−２−ピロリドン溶液（以下「２０％粗製ＴＢＳ溶液」と略記する）を得た。
【００４３】
温度計、撹拌機、真空脱水装置及び窒素気流装置を備えた２リットルの四ツ口フラスコに、ポリオキシプロピレンジオール（数平均分子量２０００、水酸基価５６．５、１分子当りの水酸基個数２個、粘度３００ｍＰａ・ｓ／２５℃、商品名：スミフェン３６００、住友バイエルウレタン社製）６００部とポリオキシプロピレントリオール（数平均分子量３０００、水酸基価５６．３、１分子当りの水酸基個数３個、粘度５００ｍＰａ・ｓ／２５℃、商品名：スミフェン３０８６、住友バイエルウレタン社製）４００部を仕込み、１００℃にて１５トール（ｔｏｒｒ）で１時間脱水した後、ＮＣＯ／ＯＨ比２．０となるように２，４−トルエンジイソシアネートと２，６−トルエンジイソシアネートの異性体混合物（商品名スミジュールＴ−８０、住友バイエルウレタン社製）１７５部を配合し、９０〜９５℃にて３時間反応させ、反応率が９０％になった時点で、５０℃に調温していた脱水を施した２０％粗製ＴＢＳ溶液を５０部配合して含有する活性水素化合物をイソシアネート基と同温度で２０分間反応させ、その後５％ジブチル錫ラウレートのジオクチルフタレート溶液を０．５部（ジブチル錫ラウレートは０．０２５部）配合して４０分反応を続け、冷却後６０℃にて、水分を取り除いた２００ｍｌガラスビンに取り分け、窒素置換後密封状態に保った。翌日完全な固形状となったゼリー状プレポリマーを得た。このゼリー状ウレタンプレポリマーは無色透明の固形状で、イソシアネート基含有率３．１６％であった。
【００４４】
このゼリー状プレポリマーを１部安息香酸イソアミルに溶解し、減圧蒸留にて、未反応トルエンジイソシアネートモノマー量を塩酸・アミン逆滴定法で測定したところ０．６４％であった。
【００４５】
比較参考例１
参考例１と同じポリオールとポリイソシアネートで同温度にて３時間２０分反応し、同様にジブチル錫ラウレートを添加した後、４０分反応を行い冷却工程に入り同条件で取り出した。これは、通常の液状プレポリマーで、イソシアネート基含有率３．４５％、２０℃における粘度は１１０００ｍＰａ・ｓであった。これを参考例１と同じ方法で未反応トルエンジイソシアネートモノマー量を測定したところ２．０５％であった。
【００４６】
即ち参考例１のプレポリマーは、粗製ＴＢＳをポリオール１００部当り１．０部を反応途中（反応率９０％）で配合したものである。一方、比較参考例１のプレポリマーは、粗製ＴＢＳを含有しない通常の液状プレポリマーである。
【００４７】
この２種のプレポリマーにつき、ゲル硬度、温度／ゲル硬度又は温度／粘度依存性試験、保存安定性試験及び再ゾル化試験を行った。
【００４８】
これらの試験方法は、以下の通りである。
【００４９】
ゲル硬度；
ＪＩＳ Ｋ ２５３０（石油アスファルト針入度試験法）に規定される針入度試験で測定した。数値が小さい程、ゲル硬度は高い。
【００５０】
温度／ゲル硬度又は温度／粘度依存性試験；
参考例１のプレポリマーについては、２０℃及び５℃にて前記の方法でゲル硬度を測定した。また比較参考例１のプレポリマーについては、２０℃及び５℃にてブルックフィールド型粘度計で粘度を測定した。
【００５１】
保存安定性試験；
２００ｇのマヨネーズビンを密封し、５０℃にて１ヶ月放置後の各試料のイソシアネート基含有率、消失変化率の算出、保存後のゲル硬度の測定及び再ゾル化試験を行った。
【００５２】
イソシアネート基の消失変化率；
イソシアネート基の消失変化率は、次式に従って計算した。
【００５３】
【数２】

【００５４】
再ゾル化試験；
５０℃×１ヵ月放置後、密封状態で８０℃×１日放置し、ゼリー状ウレタンが再ゾル化して液状に復帰するかを観察する。再び液状になった場合は、再ゾル化したものとして○で表記し、再び液状とならず不溶化を示す時は×で表記する。
【００５５】
これらの試験結果を表１に示す。尚、表１中の「特化則」とは労働安全衛生法特定化学物質等障害予防規則の略である。
【００５６】
【表１】

【００５７】
参考例１のゼリー状ウレタンプレポリマーは、完全な保形性を保つ固形状物で、液状に比べて危険性の少ない消防法可燃性固体であり、有害なトルエンジイソシアネートモノマーも１％以下であるため労働安全衛生法特定化学物質障害予防規則（以下安衛法特化則）の適用から除外される。一方比較参考例１の液状ウレタンプレポリマーは、固形より危険性に配慮が必要な可燃性液体であり、有害なトルエンジイソシアネートモノマーも１％を超えるため安衛法特化則の適用を受け、一層厳密な作業管理が必要となる。また比較参考例１の液状ウレタンプレポリマーが低温域では約９倍の粘度上昇をひき起し非常に粘稠な液状物になるのに対し、参考例１のゼリー状ウレタンプレポリマーはゲル硬度の温度依存性が少なく常温と同程度の硬さを維持している。また、保存安定性試験の結果から、参考例１のゼリー状ウレタンプレポリマーは比較参考例１の液状ウレタンプレポリマーと同程度のイソシアネート基含有率の変化程度で、初期のプレポリマーの特性を維持している。
【００５８】
実施例１及び比較例１
参考例１又は比較参考例１のウレタンプレポリマーをＡ剤とし、活性水素化合物としてポリオールを用い、これを主成分としてマスチック状に加工した製剤（商品名ボンドＵシール硬化剤、水酸基価７４、粘度１９００Ｐａ・ｓ、コニシ社製）をＢ剤とした。Ａ剤とＢ剤とからなる接合材を、次の試験に供した。
【００５９】
（１）混合作業性；
試験用シール混合機に、Ｂ剤としてボンドＵシール硬化剤を９００ｇを投入し、ＮＣＯ／ＯＨ比が１．１となるようにＡ剤として参考例１のゼリー状ウレタンプレポリマー又は比較参考例１の液状ウレタンプレポリマーを約３００ｇ配合して、Ａ剤の投入時の周囲への付着、飛び散りの度合と均質混合に至る時間を測定した。この試験は２０℃、６０％ＲＨで行った。更にこの混練りした状態の試料を次の試験で評価した。
【００６０】
（２）外観；
試料のＡ剤とＢ剤を所定量混合後、幅２０ｍｍ，深さ１０ｍｍ，長さ３００ｍｍのスレート目地に充填後、硬化後、外観の仕上がり状態を肉眼で観察する。
【００６１】
（３）ヘラならし作業性；
（２）の目地への充填時、接合材の糸ひき、ヘラならし易さを指触にて下記の基準で判定する。
【００６２】
◎：糸ひきなく、ヘラならし，し易い
○：糸ひきやゝあり、ヘラならし，普通
△：糸ひきあり、ヘラならし，やゝ悪い。
【００６３】
（４）可使時間；
ＪＩＳ Ａ ５７５８の可使時間の試験方法でテストした。
【００６４】
（５）タックフリー；
ＪＩＳ Ａ ５７５８に準じて、タックフリータイム（タックがなくなるまでの所要時間）を測定した。
【００６５】
（６）発泡率；
試料のＡ剤とＢ剤との混合物を内径１６ｍｍ，長さ５０ｍｍ（Ｌｏ）の塩化ビニル製パイプにヘラで充填し、５０℃の条件下で放置して硬化させた。硬化後塩化ビニル製パイプの両端からはみだしたものの両先端間の距離（Ｌ）をノギスで測定し、次式に従って発泡率を算出した。
【００６６】
【数３】

【００６７】
（７）Ｈ型引張接着性；
ＪＩＳ Ａ ５７５８に準じてテストした（ボンドシールプライマー ＃７（コニシ社製）、被着体：モルタル／モルタル）。
【００６８】
これら試験の結果を表２に示す。
【００６９】
【表２】

【００７０】
表２から、参考例１と比較参考例１のウレタンプレポリマーをそれぞれＡ剤として、市販のＢ剤と組合せた場合、実施例１の混合作業性の改良が認められ、その他の物性は同程度で、液状ウレタンプレポリマーの特性を維持していることが判る。
【００７１】
更に５０℃にて１ヵ月を履歴したゼリー状ウレタンプレポリマー（参考例１）及び従来の液状ウレタンプレポリマー（比較参考例１）を用い、上記と同様の試験をした。
【００７２】
これら試験の結果を表３に示す。
【００７３】
【表３】

【００７４】
表３から、保存安定試験を履歴した実施例１の接合材の各種物性は変化していない（劣化していない）ことが判る。[0001]
[Industrial applications]
The present invention relates to a urethane-based joining material.
[0002]
[Prior art and its problems]
Urethane-based joining materials such as sealing materials and adhesives are widely used in a wide range of industrial fields such as construction, civil engineering, vehicles, and the like for achieving watertightness and airtightness or for bonding. Of these, a urethane-based sealing material or adhesive called a two-pack type is used by mixing the agent A and the agent B immediately before use. The A agent is a urethane prepolymer having an isocyanate group, and the B agent is a preparation containing a compound having an active hydrogen such as a polyol. The isocyanate group of the A agent reacts with the active hydrogen of the B agent. Has a mechanism to cure.
[0003]
It is well known that the B agent is provided by mixing a compound having active hydrogen such as a polyol with various additives to finish it in a highly viscous and viscous state called a paste having poor fluidity. It is a fact. On the other hand, the prepolymer having an isocyanate group of the agent A reacts very easily with a compound having active hydrogen such as water, alcohol, organic amines, and carboxylic acid, so that the additive to be blended is limited. Agent A is usually provided as a low-viscosity liquid substance. Further, the urethane prepolymer of the agent A has a urethane bond in the molecule and has a remarkable viscosity increase in a low temperature range. Therefore, the viscosity region is set to a low viscosity of about 5,000 to 50,000 mPa · s at room temperature. . As described above, Agent A is treated as a flammable liquid belonging to Class 4 of the Dangerous Goods of the Fire Services Act because of its liquid and low-viscosity properties. Filling and storing in metal containers is obligatory from the viewpoint of preventing leakage during storage and transportation, and leakage accidents. Because of this liquid state, the agent A has restrictions on storage, transportation, etc. before use, and after use, has a great impact on the global environment due to non-burnable industrial wastes called storage metal containers. Furthermore, mixing with low-viscosity liquid A agent dilutes B agent, which has a poor flowability and is finished to a high-viscosity state, resulting in proper sealing and bonding operations when using a urethane-based bonding material. Since it becomes difficult to maintain the environment, it becomes necessary to finish the agent B with a particularly high viscosity. In addition, in the mixing operation at the time of use, since the viscosity difference between the agent A and the agent B is high, it is difficult to perform homogeneous mixing and a long time is required. In addition, there were several difficulties in the mixing operation, such as the low-viscosity agent A was easily scattered around by the blades of the stirrer during mixing. In addition, the urethane prepolymer of the agent A contains not only the danger based on the flammable liquid but also the residual isocyanate monomer which is harmful to the human body and causes environmental pollution. Further, promoting volatilization of the isocyanate monomer is one of the difficulties.
[0004]
As described above, the conventional two-pack type urethane-based bonding material has to provide the urethane prepolymer, which is the agent A, as a low-viscosity liquid material. There are issues such as solving industrial waste problems and improving mixing work.
[0005]
[Means for Solving the Problems]
In urethane-based sealing materials and adhesives, conventional problems can be solved if the difficulties caused by the liquid prepolymer serving as the agent A can be overcome. However, the means for solving the difficulty of being a liquid must maintain excellent properties such as the reactivity of the conventional prepolymer, have excellent handling properties, and be easily liquefied by the shearing force of the stirrer during mixing. Must. Therefore, a technique for obtaining a viscous high-viscosity state in the form of a paste with poor fluidity, which has been conventionally proposed for a prepolymer, cannot completely solve the conventional problems. Therefore, the present inventor has provided a completely new concept of giving a prepolymer in a liquid form a perfect shape retention property like jelly, which has a property of being easily liquefied by a shearing force, and is inherently provided. It was thought that if a prepolymer maintaining the excellent reactivity could be obtained, all conventional problems could be solved.
[0006]
Based on this concept, when various gelling agents were added to the urethane prepolymer, the isocyanate group content decreased over time, even if complete shape retention could be imparted, or the urethane prepolymer was easily liquefied due to strong shearing force. I didn't find anything to do. Among them, we have found that tribenzylidene sorbitol gives perfect shape retention due to thermoreversible sol-gel change and has the property of easily liquefying under strong shearing force, but the isocyanate group content decreases with time. It has also been found that some irreversible gelling polymers are unavoidable.
[0007]
As a result of examining such a phenomenon in detail, tribenzylidene sorbitol always contains an active hydrogen compound (by-product) such as dibenzylidene sorbitol having a hydroxyl group in the molecule. It was thought that it promoted the formation of a novel gelling polymer. That is, commercially available tribenzylidene sorbitol always contains a few percent of hydroxyl group-containing by-products such as dibenzylidene sorbitol. The reaction between the hydrogen and the prepolymer eventually results in the partial formation of a thermally irreversible gelled polymer.
[0008]
Therefore, the above problem can be solved by purifying tribenzylidene sorbitol. However, purification and separation of by-products is extremely difficult, and the number of complicated steps is increased.
[0009]
In view of the above circumstances, the present inventor considers that there is an undesired by-product in tribenzylidene sorbitol, and if it is difficult to purify and isolate the by-product, it is only necessary to eliminate the effects of the by-product. Addition of a solution prepared by dissolving tribenzylidene sorbitol containing an active hydrogen compound and / or a derivative thereof in an organic solvent inert to isocyanate groups at the start of or during the reaction during the production of a urethane prepolymer with polyisocyanate Then, an attempt was made to stabilize the by-product by elimination of active hydrogen contained in the by-product with isocyanate, and a jelly-like urethane prepolymer stable over time was successfully obtained. The concept of the jellified urethane prepolymer having a shape-retaining property and an isocyanate group referred to in the present invention gives a thermoreversible sol-gel over a long period of time and does not give a thermoirreversible gelled polymer. A gelled polymer is a mechanism that is formed only when a prepolymer reacts with active hydrogen. Such a concept is not a conventional paste-like viscous urethane prepolymer, but a concept of completely maintaining shape retention.
[0010]
Using this jelly-like urethane prepolymer as the agent A, the jelly-like prepolymer immediately after production or stored for a long time is processed into a high-viscosity paste by a conventional method using a compound having active hydrogen capable of reacting with an isocyanate group. Adds various physical properties that do not change at all from conventional liquid prepolymers when mixed with the agent, reduces danger and harmfulness, considers the impact on the environmental load such as industrial waste problems due to the use of metal cans, handling properties, and mixability. Conventional problems such as improvement of mixing work such as easiness have been solved at once. The present invention has been completed based on such findings.
[0011]
That is, the present invention provides a jelly-like urethane prepolymer comprising a urethane prepolymer obtained by reacting a polyol with an excess of polyisocyanate, tribenzylidene sorbitol and / or a derivative thereof, and an organic solvent inert to isocyanate groups. A urethane-based bonding material, wherein the agent B is a paste-like composition containing a compound having active hydrogen capable of reacting with an isocyanate group.
[0012]
The jelly-like urethane prepolymer used as the agent A in the present invention is produced by the following method.
[0013]
In the present invention, tribenzylidene sorbitol containing an active hydrogen compound has the following composition. That is, tribenzylidene sorbitol is usually produced by a condensation reaction of 3 mol of benzaldehyde and 1 mol of sorbitol. Further, a derivative of tribenzylidene sorbitol is produced by a condensation reaction of a benzaldehyde derivative substituted with an alkyl group, a nitro group, a halogen atom, and the like with sorbitol. These tribenzylidene sorbitols and derivatives thereof are compounds in which 6 hydroxyl groups per molecule of sorbitol are blocked with benzylidene groups, and do not have a portion that theoretically reacts with an isocyanate group. Active hydrogen compounds such as dibenzylidene sorbitol having two hydroxyl groups in the molecule of about 2% by weight, monobenzylidene sorbitol having four hydroxyl groups in the molecule, and sorbitol having six hydroxyl groups in the unreacted molecule are secondary. Raw and mixed. Since these active hydrogen compounds are very difficult to purify and separate, tribenzylidene sorbitol containing these compounds is generally commercially available. In the present invention, such commercially available products can be used as they are.
[0014]
The above-mentioned active hydrogen compound-containing tribenzylidene sorbitol and / or a derivative thereof (hereinafter, abbreviated as “crude TBS”) is used after being dissolved in various organic solvents. It is necessary that the organic solvent is an organic solvent inert to the isocyanate group. Examples of such an organic solvent include polar organic solvents such as N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethylsulfoxide, tetrahydrofuran, methyl cellosolve acetate, ethyl cellosolve acetate, Ethylene glycol ethers such as butyl cellosolve acetate, methyl carbitol acetate, ethyl carbitol acetate, esterified propylene glycol ethers such as propylene glycol monomethyl ether acetate, and phthalic diesters such as dibutyl phthalate and dioctyl phthalate And ester solvents including monocarboxylic esters such as butyl acetate and dicarboxylic diesters such as dioctyl adipate. . Such organic solvents are used alone or in combination of two or more. Among these organic solvents, N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethylsulfoxide, ethylene glycol ethers are given as those which give relatively good solubility to crude TBS. At least one of an esterified product and an esterified product of a propylene glycol ether is preferable.
[0015]
In dissolving the crude TBS in the above organic solvent, there is no particular limitation, and conventionally known methods can be widely used. For example, in consideration of the solubility of the selected organic solvent in crude TBS, 0.1 to 10 parts by weight of crude TBS may be added per 0.3 to 30 parts by weight of the organic solvent and dissolved by heating.
[0016]
In the present invention, when producing a urethane prepolymer having an isocyanate terminal by reacting a polyol with an excess of polyisocyanate, the above-mentioned organic solvent solution of crude TBS is present in the reaction system at the start of or during the reaction. The organic solvent solution of the crude TBS may be added to the reaction system in a state of being heated and dissolved, or even if the crude TBS is in a gelled state after the crude TBS has undergone a sol-gel change, it may be directly added to the reaction system. What is necessary is just to add. If precipitation of crude TBS is recognized due to a change in solubility upon cooling, it is preferable to redissolve and use. Further, when a small amount of water is present in the crude TBS or the organic solvent, the water in the crude TBS or the organic solvent may be removed by using an appropriate amount of a water removing agent such as a molecular sieve. The timing of adding the crude TBS organic solvent solution into the reaction system is preferably during the reaction. In particular, when the reaction rate between the polyol and the polyisocyanate reaches about 20 to 95%, particularly about 30 to 90%, it is preferable to add the organic solvent solution of the above crude TBS. Here, the reaction rate is defined as the isocyanate group content (NCO%) in the total amount of polyol and polyisocyanate as A, the value obtained by subtracting the theoretical NCO% of the prepolymer from A as B, and the measured NCO% as C, It is obtained according to the formula.
[0017]
(Equation 1)

[0018]
The addition of the organic solvent solution of the crude TBS may be completed once, may be performed several times, or may be performed continuously.
[0019]
In the present invention, the prepolymer is produced by polymerizing a polyol and an excess of polyisocyanate.
[0020]
As the polyol used in the present invention, conventionally known polyols can be widely used as long as they are polyhydric alcohols having two or more hydroxyl groups at the molecular terminals. Specifically, the following polyols can be exemplified by classifying them by chemical bonds in the molecules such as polyether polyols and polyester polyols.
[0021]
That is, examples of the polyether polyol having an ether bond in the molecule include polyoxyalkylene diols (specifically, polyoxyethylene glycol, polyoxypropylene glycol, polyoxybutylene glycol, and copolymers thereof), and polyoxyalkylene diols. Polyoxyalkylene polyols such as triol (specifically, ethylene oxide, propylene oxide, butylene oxide, styrene oxide, etc. and glycerin, trimethylolpropane, etc.), and polyoxytetramethylene obtained by ring-opening polymerization of tetrahydrofuran In addition to glycols and the like, diols and triols to which ethylene oxide or propylene oxide is added using bisphenols, sugars, amines such as ethylenediamine as starting materials, and the like are given. Door can be.
[0022]
As the polyester polyol having an ester bond in the molecule, a conventionally known polyester polyol can be widely used as long as it is a compound having a hydroxyl group at a terminal having an ester bond as a repeating unit. Specifically, a condensation-based polyester polyol obtained by dehydration condensation of a polyhydric carboxylic acid (mainly adipic acid or phthalic acid) with a polyhydric alcohol (specifically, glycol, triol, etc.); ring-opening polymerization of ε-caprolactone A lactone-based polyester polyol obtained by the method described above; a polycarbonate diol obtained by phosgenation of a polyol or a transesterification reaction with diphenylene carbonate; a polyester polyol obtained by a polyaddition reaction between a polycarboxylic acid anhydride and diepoxide; Urethane-modified polyester polyols as introduced can be mentioned.
[0023]
In the present invention, these polyols are used alone or as a mixture of two or more.
[0024]
On the other hand, the polyisocyanate used in the present invention is a compound having two or more isocyanate groups in one molecule, a so-called polyfunctional isocyanate compound. Examples of such polyfunctional isocyanate compounds include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate and a mixture of isomers thereof, 4,4′-diphenylmethane diisocyanate (hereinafter, referred to as “4,4′-MDI”), , 4′-MDI and 2,4′-diphenylmethane diisocyanate (hereinafter referred to as “2,4′-MDI”) (trade name: Luplanate MI, manufactured by BSF Japan), carbodiimide-modified diphenylmethane diisocyanate, crude MDI, hexa Methylene diisocyanate (hereinafter referred to as “HMDI”), xylene diisocyanate (hereinafter referred to as “XDI”), metaxylylene diisocyanate, 1,5-naphthalenediisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated toluene diisocyanate Isocyanate compounds such as cyanate, hydrogenated xylene diisocyanate and isophorone diisocyanate; burette polyisocyanate compounds such as Sumidur N (manufactured by Sumitomo Bayer Urethane); Desmodur IL, HL (manufactured by Bayer AG), Coronate EH (Japan) Polyisocyanate compounds having an isocyanate ring such as Polyurethane Industry Co., Ltd .; polyisocyanate compounds having an adduct polyisocyanate ring such as Sumidur L (manufactured by Sumitomo Bayer Urethane Co.) and Coronate HL (manufactured by Nippon Polyurethane Industry Co., Ltd.). Can be mentioned.
[0025]
In the present invention, these polyisocyanates are used alone or in combination of two or more.
[0026]
No particular limitation is imposed on the synthesis of the prepolymer, and the prepolymer may be produced by a conventionally known method. Excess polyisocyanate means that the isocyanate equivalent is excessive compared to the OH group equivalent of the polyol, and the equivalent relation can be represented by the NCO / OH ratio. That is, theoretically, if the NCO / OH ratio is set to 1 or more, an isocyanate terminal can be obtained. However, in the present invention, from the viewpoint that the prepolymer can take a liquid form at a high temperature and a jelly form at around a room temperature, the NCO is usually used. The / OH ratio is preferably 1.5 or more. Although the upper limit of the NCO / OH ratio is not particularly limited, the NCO / OH ratio is more preferably 10 or less. In particular, in order to obtain a liquid and low-viscosity prepolymer, it is particularly preferable to adjust the NCO / OH ratio to about 2 to 10 while considering the type, the number of functional groups, and the molecular weight of the polyol. Although the polymerization temperature and the polymerization time are not particularly limited, it is generally preferable to mix the polyol and the polyisocyanate under a nitrogen stream to react at 50 to 100 ° C. for 3 to 8 hours in order to avoid the influence of moisture. Before, during and after the reaction, an appropriate amount of an organometallic urethane polymerization catalyst, a stabilizer, a moisture promoter, a polymerization regulator and the like may be added as needed.
[0027]
In the method of the present invention, at the start of the polymerization reaction or during the polymerization reaction, an organic solvent solution of crude TBS is allowed to exist in the reaction system, and the hydroxyl group of the polyol and the by-product hydroxyl group are reacted at 50 to 80 ° C. It is characterized by elimination with excess polyisocyanate in the temperature range.
[0028]
Therefore, at the time of starting the polymerization or during the course of the reaction, if an organic solvent solution of crude TBS (hereinafter abbreviated as “C-TBS solution”) is not blended, since unreacted by-products having active hydrogen are present, The content of the isocyanate cannot be fixed, and as a result, a long-term stable jelly-like urethane resin cannot be obtained, and a gelled polymer is formed over time, resulting in a thermo-irreversible gel. That is, if the isocyanate content disappears with time, the excellent reactivity characteristic of the jelly-like urethane is impaired, so that the object of the present invention cannot be met.
[0029]
In the present invention, it is possible to add a C-TBS solution to the polyol in advance, mix the polyisocyanate, and then carry out a polymerization reaction at 50 to 100 ° C., which is a normal urethane polymerization temperature, for 3 to 8 hours. By-products having hydrogen tend to cause side reactions, lower the isocyanate content, and cause a yellowing tendency of the obtained jelly-like urethane resin, so that the C-TBS solution is converted when the reaction rate is 20 to 95%. Preferably, it is present in the reaction system. In the present invention, when the reaction rate reaches 30 to 90%, a C-TBS solution is added, and then an organometallic urethane polymerization catalyst such as dibutyltin dilaurate is added in an amount of 0.0005 to 0.02 per 100 parts by weight of the polyol. It is particularly preferable to employ a method of promoting the urethanization reaction with active hydrogen such as unreacted hydroxyl groups by adding parts by weight.
[0030]
Further, when crude TBS is blended at a reaction rate of 30 to 90% as described above, it becomes an effective means for reducing harmful unreacted isocyanate monomers such as toluene diisocyanate, and can reduce adverse effects on human bodies and the environment.
[0031]
In order to obtain a jelly-like urethane prepolymer, a solution in which 0.1 to 10 parts by weight of crude TBS is dissolved in 0.3 to 30 parts by weight of an organic solvent per 100 parts by weight of an urethane prepolymer having an isocyanate terminal (C-TBS solution) Is desirably added. The jelly form as used in the present invention is one that retains shape retention, and is specifically an agar, a semi-solid state in which jelly is hardened, or an elasticity such as a commercially available office glue stick. With a solid In addition, this jelly state has little temperature dependence of gel hardness as in ordinary liquid urethane in which a sharp increase in viscosity is observed in a low temperature range.
[0032]
Therefore, when the amount of the crude TBS is less than 0.1 part by weight, the urethane prepolymer tends to be in a liquid state. On the other hand, when the amount is more than 10 parts by weight, the isocyanate content rapidly disappears with time, resulting in poor stability. It is difficult to obtain, and the obtained gelled substance also tends to give a hard and brittle gelled substance that has lost elasticity, and also tends to cause precipitation of crude TBS over time and impair the quality as a gelled body. Therefore, neither is preferable. A preferable range for obtaining a semi-solid state and an elastic solid state from a thixotropic viscous substance such as pomade intended in the present invention is 0.5 to 7 parts by weight of crude TBS per 100 parts by weight of prepolymer (more preferably 0 to 7 parts by weight). 0.6 to 3 parts by weight), and 1.5 to 20 parts by weight (more preferably 1.8 to 9 parts by weight) of the organic solvent.
[0033]
The jelly-like prepolymer of the present invention may contain various additives that are usually added to the prepolymer. Examples thereof include thickeners such as anhydrous silica and amide wax, moisture catchers such as toluenesulfonyl isocyanate, plasticizers, organic solvents, tackifying resins, other polymers, and stabilizers.
[0034]
On the other hand, the agent B in the present invention is a paste composition containing a compound having active hydrogen capable of reacting with an isocyanate group. As such a paste-like composition, those conventionally used as a B agent in this kind of two-pack type urethane-based bonding material can be widely used. Specifically, hydroxyl group, amino group, active hydrogen such as carboxyl group in the molecule, preferably a compound having a hydroxyl group, an inorganic filler, a thickener, various additives and the like are blended, usually its properties are It has a high viscosity paste with poor fluidity. Examples of the active hydrogen compound include polyols used as starting materials for the synthesis of the prepolymer of the present invention, and conventional urethane prepolymers such as those obtained by blending the polyols with other active hydrogen compounds such as amine compounds and carboxylic acids. The compound used for the agent B that can react with the agent (A) can be widely used.
[0035]
The agent A and the agent B may be blended in consideration of the equivalent ratio, and the blending ratio is not different from the case where a conventional prepolymer is used as the agent A. That is, the equivalent ratio of the B agent may be selected based on the isocyanate group content of the jelly-like prepolymer.
[0036]
For example, when a paste containing a polyol having a hydroxyl group is used as the agent B, the hydroxyl value and the equivalent ratio of the isocyanate group of the agent A are usually used. The ratio of NCO / OH is usually 1 to 3, preferably 1 to 1.5. May be set in the range. In short, as in the case of a general liquid prepolymer, the equivalent ratio may be determined by a known method depending on the purpose in consideration of the isocyanate group content of the jelly-like prepolymer.
[0037]
【The invention's effect】
In the bonding material of the present invention, since the jelly-like prepolymer as the agent A has perfect shape retention, the flammability with high danger and harmfulness of various laws and regulations typified by the Fire Service Law Dangerous Goods Class 4 Since it is not a liquid but a flammable solid, it is possible to prevent leakage and accidents during storage or transportation. In addition, because of this safety, the storage container does not need to use a metal container which tends to be an industrial waste problem, and a container made of processed paper which does not give a burden on the environment can be freely selected.
[0038]
When the agent A is mixed with the agent B at the time of use, the difference in viscosity between the agent A and the agent B is small, and the mixture is easily liquefied by the strong shearing force of the stirrer, so that the mixing property is excellent and the mixing time is short. Further, in order to maintain the shape retention at the start of stirring, there is no scattering as observed in a liquid state. Therefore, the joining material of the present invention has a greatly improved mixing workability.
[0039]
Further, when producing a jelly-like prepolymer, tribenzylidene sorbitol containing an active hydrogen compound is caused to be present in the reaction system during or after the reaction, so that harmful residual isocyanate monomers are consumed, and the residual isocyanate harmful to the human body is consumed. It is a measure to reduce compounds.
[0040]
The jelly-like prepolymer, which is the agent A of the bonding material of the present invention, has a feature that once gelled, there is no increase in viscosity in a low-temperature region seen in a liquid prepolymer, and the gel hardness is hardly affected by temperature. Have.
[0041]
【Example】
Hereinafter, the present invention will be further clarified with reference to examples of the present invention, but the present invention is not limited to these examples. In the following, simply “parts” and “%” mean “parts by weight” and “% by weight” unless otherwise specified.
[0042]
Reference Example 1
A one-liter three-necked flask equipped with a thermometer, a reflux tube, and a stirrer is charged with 400 parts of N-methyl-2-pyrrolidone, and industrial tribenzylidene sorbitol (active hydrogen compound content: 3%, water content: 1%, slightly yellowish) 100 parts of powder (trade name: Gelall T, manufactured by Shin Nippon Rika Co., Ltd.) was mixed and dissolved at 80 ° C. for 30 minutes to obtain a yellow transparent solution. In order to remove the water in the solution, an appropriate amount of a water adsorbent molecular sieve granules is blended and an N-methyl-2-pyrrolidone solution of tribenzylidene sorbitol containing 20% of an active hydrogen compound (hereinafter referred to as “20% crude TBS Solution ").
[0043]
In a 2-liter four-necked flask equipped with a thermometer, a stirrer, a vacuum dehydrator, and a nitrogen gas streamer, polyoxypropylene diol (number-average molecular weight: 2,000, hydroxyl value: 56.5, number of hydroxyl groups per molecule: 2, Viscosity 300 mPa · s / 25 ° C., trade name: Sumifene 3600, 600 parts by Sumitomo Bayer Urethane Co., Ltd. and polyoxypropylene triol (number average molecular weight 3000, hydroxyl value 56.3, number of hydroxyl groups per molecule 3, viscosity 500 mPas)・ 400 parts of s / 25 ° C., trade name: Sumifen 3086, manufactured by Sumitomo Bayer Urethane Co., Ltd.), and after dehydrating at 100 ° C. for 15 hours at 15 torr, the NCO / OH ratio is adjusted to 2.0. An isomer mixture of 2,4-toluene diisocyanate and 2,6-toluene diisocyanate (trade name: Sumidur T- 0, manufactured by Sumitomo Bayer Urethane Co., Ltd.), and reacted at 90 to 95 ° C. for 3 hours. When the reaction rate reached 90%, dehydration was performed at 50 ° C. and 20% was applied. An active hydrogen compound containing 50 parts of a crude TBS solution is reacted with an isocyanate group at the same temperature for 20 minutes, and then 0.5 parts of a dioctyl phthalate solution of 5% dibutyltin laurate (0.025 parts of dibutyltin laurate is used). ) After blending, the reaction was continued for 40 minutes. After cooling, the mixture was separated into 200 ml glass bottles from which water had been removed at 60 ° C, and kept sealed after replacement with nitrogen. The next day, a completely solid jelly-like prepolymer was obtained. This jelly-like urethane prepolymer was a colorless and transparent solid, and had an isocyanate group content of 3.16%.
[0044]
One part of this jelly-like prepolymer was dissolved in isoamyl benzoate, and the amount of unreacted toluene diisocyanate monomer measured by distillation under reduced pressure was 0.64% as measured by hydrochloric acid / amine reverse titration method.
[0045]
Comparative Reference Example 1
The same polyol and polyisocyanate as in Reference Example 1 were reacted at the same temperature for 3 hours and 20 minutes, and after adding dibutyltin laurate in the same manner, a reaction was performed for 40 minutes, and the mixture was cooled and taken out under the same conditions. This was a normal liquid prepolymer, having an isocyanate group content of 3.45% and a viscosity at 20 ° C. of 11,000 mPa · s. When the amount of the unreacted toluene diisocyanate monomer was measured by the same method as in Reference Example 1, it was 2.05%.
[0046]
That is, the prepolymer of Reference Example 1 was prepared by mixing 1.0 part of crude TBS per 100 parts of polyol in the middle of the reaction (reaction rate: 90%). On the other hand, the prepolymer of Comparative Reference Example 1 is a normal liquid prepolymer containing no crude TBS.
[0047]
The two types of prepolymers were subjected to a gel hardness, temperature / gel hardness or temperature / viscosity dependency test, a storage stability test, and a resolving test.
[0048]
These test methods are as follows.
[0049]
Gel hardness;
It measured by the penetration test prescribed | regulated to JISK2530 (petroleum asphalt penetration test method). The smaller the value, the higher the gel hardness.
[0050]
Temperature / gel hardness or temperature / viscosity dependency test;
The gel hardness of the prepolymer of Reference Example 1 was measured at 20 ° C. and 5 ° C. by the method described above. The viscosity of the prepolymer of Comparative Reference Example 1 was measured at 20 ° C. and 5 ° C. using a Brookfield viscometer.
[0051]
Storage stability test;
200 g of mayonnaise bottle was sealed, and after left at 50 ° C. for 1 month, the isocyanate group content and the disappearance change rate of each sample were calculated, the gel hardness after storage, and the resolving test were performed.
[0052]
Loss rate of isocyanate group change;
The disappearance change rate of the isocyanate group was calculated according to the following equation.
[0053]
(Equation 2)

[0054]
Resolving test;
After leaving at 50 ° C. for one month, the container is left in a sealed state at 80 ° C. for one day, and it is observed whether or not the jelly-like urethane re-solves and returns to a liquid state. When it becomes liquid again, it is represented by と し て as resolubilized, and when it becomes insoluble again without becoming liquid again, it is represented by x.
[0055]
Table 1 shows the test results. The "specialization rule" in Table 1 is an abbreviation of the Occupational Safety and Health Act's Regulations on Prevention of Disorders for Specific Chemical Substances.
[0056]
[Table 1]

[0057]
The jelly-like urethane prepolymer of Reference Example 1 is a solid that maintains perfect shape retention, is a fire-resistant flammable solid that is less dangerous than liquid, and has a harmful toluene diisocyanate monomer content of 1% or less. Therefore, they are exempt from the application of the Occupational Safety and Health Act's Regulations on Prevention of Specific Chemical Substance Injuries (hereinafter referred to as the Safety Regulations). On the other hand, the liquid urethane prepolymer of Comparative Reference Example 1 is a flammable liquid that needs to be considered more hazardous than a solid, and the harmful toluene diisocyanate monomer also exceeds 1%. Work management is required. Further, the liquid urethane prepolymer of Comparative Reference Example 1 caused an increase in viscosity by about 9 times in a low temperature range to become a very viscous liquid substance, whereas the jelly-like urethane prepolymer of Reference Example 1 had a gel hardness. It has low temperature dependence and maintains the same hardness as normal temperature. Also, from the results of the storage stability test, the jelly-like urethane prepolymer of Reference Example 1 maintains the properties of the initial prepolymer with the same degree of change in the isocyanate group content as the liquid urethane prepolymer of Comparative Reference Example 1. are doing.
[0058]
Example 1 and Comparative Example 1
A formulation prepared by using the urethane prepolymer of Reference Example 1 or Comparative Reference Example 1 as an agent A, and using a polyol as an active hydrogen compound, and processing it into a mastic form using the same as a main component (trade name: Bond U seal hardener, hydroxyl value 74, viscosity 1900 Pa · s, manufactured by Konishi Co., Ltd.). The joining material composed of the A agent and the B agent was subjected to the following test.
[0059]
(1) mixing workability;
900 g of a bond U seal hardener was added as a B agent to a test seal mixer, and the jelly-like urethane prepolymer of Reference Example 1 or Comparative Reference Example 1 was used as an A agent so that the NCO / OH ratio was 1.1. About 300 g of the liquid urethane prepolymer was blended, and the degree of adhesion and scattering to the surroundings when the agent A was charged and the time until homogeneous mixing were measured. This test was performed at 20 ° C. and 60% RH. The kneaded sample was evaluated in the following test.
[0060]
(2) appearance;
After mixing a predetermined amount of the A agent and the B agent of the sample, filling the slate joint having a width of 20 mm, a depth of 10 mm, and a length of 300 mm, and after curing, the finished state of the appearance is visually observed.
[0061]
(3) Spatula workability;
At the time of filling into the joint of (2), the threading of the joining material and the ease with which the spatula is made are determined by touching with the following criteria.
[0062]
◎: No thread, no spatula, easy to do
○: There is a thread sinker, spatula, normal
△: There is stringing, spatula, bad.
[0063]
(4) pot life;
The test was performed according to the pot life test method of JIS A 5758.
[0064]
(5) tack-free;
According to JIS A 5758, tack free time (time required until tack disappeared) was measured.
[0065]
(6) Foaming rate;
The mixture of the A agent and the B agent of the sample was filled into a vinyl chloride pipe having an inner diameter of 16 mm and a length of 50 mm (Lo) with a spatula, and was left to cure at 50 ° C. After curing, the distance (L) between both ends of the vinyl chloride pipe protruding from both ends was measured with a caliper, and the foaming ratio was calculated according to the following equation.
[0066]
(Equation 3)

[0067]
(7) H-type tensile adhesion;
The test was performed according to JIS A 5758 (bond seal primer # 7 (manufactured by Konishi), adherend: mortar / mortar).
[0068]
Table 2 shows the results of these tests.
[0069]
[Table 2]

[0070]
From Table 2, when the urethane prepolymers of Reference Example 1 and Comparative Reference Example 1 were used as Agent A, respectively, and combined with a commercially available Agent B, the mixing workability of Example 1 was improved, and other physical properties were comparable. This shows that the properties of the liquid urethane prepolymer are maintained.
[0071]
Further, the same test as above was conducted using a jelly-like urethane prepolymer (Reference Example 1) and a conventional liquid urethane prepolymer (Comparative Reference Example 1) which had been stored at 50 ° C. for one month.
[0072]
Table 3 shows the results of these tests.
[0073]
[Table 3]

[0074]
From Table 3, it can be seen that the various physical properties of the bonding material of Example 1, which had been subjected to the storage stability test, did not change (not deteriorated).

Claims (6)

Urethane prepolymer A agent was obtained by the reaction of excess polyisocyanate and polyol, the tribenzylidenesorbitol and / or derivatives thereof, and an isocyanate group jellied urethane prepolymer der consisting inert organic solvents, active hydrogen A jelly urethane prepolymer produced by allowing a solution in which tribenzylidene sorbitol containing a compound and / or a derivative thereof is dissolved in an organic solvent inert to an isocyanate group to be present in a reaction system at the start of or during the reaction. And
A urethane-based bonding material, wherein the agent B is a paste composition containing a compound having active hydrogen capable of reacting with an isocyanate group. The urethane-based bonding according to claim 2, wherein 0.1 to 10 parts by weight of tribenzylidene sorbitol and / or a derivative thereof and 0.3 to 30 parts by weight of an organic solvent inert to an isocyanate group are used per 100 parts by weight of the polyol. Wood. The jelly-like urethane prepolymer of the agent A is obtained by preliminarily reacting a polyol with an excess of polyisocyanate, and when the conversion reaches 20 to 95%, the tribenzylidene is dissolved in an organic solvent inert to isocyanate groups. Claims: It is produced by adding sorbitol and / or a derivative thereof, and then allowing 0.0005 to 0.02 parts by weight of an organometallic urethane polymerization catalyst per 100 parts by weight of a polyol component to be present in the reaction system. 2. The urethane-based bonding material according to 1. Organic solvents inert to isocyanate groups include N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethylsulfoxide, esters of ethylene glycol ethers and propylene glycol ethers. The urethane-based joining material according to any one of claims 1 to 3, wherein the urethane-based joining material is at least one selected from esterified products. The urethane-based bonding material according to claim 1, which is used as a sealing material. The urethane-based bonding material according to claim 1, which is used as an adhesive.