JP2004115705A - Solventless moisture-curable hot-melt urethane resin composition, foamed product and sheet structure using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solventless moisture-curable hot-melt urethane resin composition that gives a high performance porous layer having excellent adhesive properties, excellent foamability and excellent durability (especially, hydrolysis resistance and heat resistance) at the same time, to provide a foamed product and a sheet structure using the foamed product and to provide a process for producing the sheet structure. <P>SOLUTION: The solventless moisture-curable hot-melt urethane resin composition comprises as the essential components (A) an isocyanate group-containing hot-melt urethane prepolymer having a softening point in the range of 30-160°C, (B) a polyisocyanate component, (C) a compound having at least two active hydrogens and (D) water wherein the content of the total isocyanate groups based on the total weight of the prepolymer (A) and the polyisocyanate component (B) is in the range of 2.0-10.0 wt.%. <P>COPYRIGHT: (C)2004,JPO

Description

【００２８】
（但し、一般式［１］中のＲ_１　は、水素原子又はアルキル基、アリール基若しくはアラルキル基より選ばれる一価の有機基を、Ｒ_２　は、ハロゲン原子又はアルコキシル基、アシロキシ基、フェノキシ基、イミノオキシ基若しくはアルケニルオキシ基を表し、また、ｎは０又は１若しくは２なる整数を表す。）
【００２９】
上記加水分解性シリル基の中でも、トリメトキシシリル基、トリエトキシシリル基、（メチル）ジメトキシシリル基、（メチル）ジエトキシシリル基などが架橋が進行し易い点から好ましい。
【００３０】
本発明で使用するイソシアネート基と反応し得る官能基と、加水分解性シリル基とを併有する化合物としては、例えば、γ−（２−アミノエチル）アミノプロピルトリメトキシシラン、γ−（２−ヒドロキシルエチル）アミノプロピルトリメトキシシラン、γ−（２−アミノエチル）アミノプロピルトリエトキシシラン、γ−（２−ヒドロキシルエチル）アミノプロピルトリエトキシシラン、γ−（２−アミノエチル）アミノプロピルメチルジメトキシシラン、γ−（２−アミノエチル）アミノプロピルメチルジエトキシシラン、γ−（２−ヒドロキシルエチル）アミノプロピルメチルジメトキシシラン、γ−（２−ヒドロキシルエチル）アミノプロピルメチルジエトキシシランまたはγ−（Ｎ，Ｎ−ジ−２−ヒドロキシルエチル）アミノプロピルトリエトキシシラン、γ−アミノプロピルトリメトキシシラン、γ−アミノプロピルトリエトキシシラン、γ−アミノプロピルメチルジメトキシシラン、γ−アミノプロピルメチルジエトキシシランまたはγ−（Ｎ−フェニル）アミノプロピルトリメトキシシラン等が挙げられる。
【００３１】
更に、本発明では、プレポリマー（Ａ）は、ポリオール成分を２種類以上併用してもよく、又、併用するポリオール成分、ポリイソシアネート成分の種類は特に限定するものではない。
【００３２】
また、プレポリマー（Ａ）の軟化点は、好ましくは３０〜１６０℃の範囲であり、より好ましくは４０〜１００℃の範囲である。プレポリマー（Ａ）の軟化点がかかる範囲であれば、ムラのない安定した均一な発泡体が得られ、また、水で発泡させた発泡セルの冷却固化時間の適切化が図れるため、好ましい。
【００３３】
本発明で使用するプレポリマー（Ａ）の軟化点の調整方法としては、特に制限はなく、例えば、▲１▼分子量による調整方法（ポリオール成分とポリイソシアネート成分とのモル比、高分子量ポリオールの使用、高分子ポリマーの使用等）、▲２▼ポリエステル系ポリオールのエチレン鎖の結晶性による調整方法、▲３▼ポリオール成分やポリイソシアネート成分の芳香族環の構造による調整方法、▲４▼ウレタン結合の量による調整方法等がある。
【００３４】
本発明で使用するプレポリマー（Ａ）を調製するには、公知慣用の種々の方法を用いればよく、特に限定はしない。
【００３５】
一般的には、イソシアネート基末端ウレタンプレポリマー（ａ−１）の場合は、原料イソシアネート成分に水分を除去したポリオール成分を滴下して加熱してポリオール成分の水酸基が無くなるまで反応して得られる。また、加水分解性アルコキシシリル基及びイソシアネート基を有するウレタンプレポリマー（ａ−２）の場合は、上記のようにして得られたイソシアネート基末端ウレタンプレポリマー（ａ−１）に、ＮＣＯ基と反応する基を有するアルコキシシラン化合物を滴下し、必要に応じて加熱して反応して得られる。この反応は無溶剤で行われるが場合によっては有機溶剤中で行い、その後脱溶剤することでも得られる。有機溶剤中で反応させる場合には、酢酸エチル、酢酸ｎ−ブチル、メチルエチルケトン、トルエン等の公知慣用の種々の有機溶剤の使用が可能であり、反応を阻害しない有機溶剤であれば特に限定しない。この場合、反応終了後、減圧加熱に代表される脱溶剤方法により溶剤を除去することが必要である。
【００３６】
次に、本発明で使用するポリイソシアネート成分（Ｂ）としては、例えば、フェニレンジイソシアネート、トリレンジイソシアネート（ＴＤＩ）、４，４’−ジフェニルメタンジイソシアネート、２，４−ジフェニルメタンジイソシアネート、ナフタレンジイソシアネート等の芳香族ジイソシアネートやヘキサメチレンジイソシアネート、リジンジイソシアネート、シクロヘキサンジイソシアネート、イソホロンジイソシアネート、ジシクロヘキシルメタンジイソシアネート、キシリレンジイソシアネート、テトラメチルキシリレンジイソシアネートなどの脂肪族あるいは脂環族ジイソシアネート等のポリイソシアネート成分のうち、１種或いは２種類以上の混合物が使用できる。これらの中で、溶融して使用するホットメルトウレタン樹脂組成物に用いられることを考慮した場合、加熱時の蒸気圧が低いポリイソシアネートを用いることが好ましく、かかるポリイソシアネートの中でもジフェニルメタンジイソシアネート（ＭＤＩ）を用いることが特に好ましい。
【００３７】
これらポリイソシアネート成分（Ｂ）の使用量は、プレポリマー（Ａ）とポリイソシアネート成分（Ｂ）の総重量に対する総ＮＣＯ基含有率が、好ましくは２．０〜１０．０重量％の範囲であり、より好ましくは２．５〜８．０重量％の範囲である。ポリイソシアネート成分（Ｂ）の使用量がかかる範囲であれば、良好な発泡性及び架橋密度向上による耐久性（特に、耐熱性、耐加水分解性）が良好となる。
【００３８】
かかるポリイソシアネート成分（Ｂ）の添加方法としては、プレポリマー（Ａ）の合成のポリイソシアネート添加前にかかる範囲のポリイソシアネート成分（Ｂ）を先に添加すると、プレポリマー（Ａ）の分子量が大きくならないため、初期凝集力が発現せずに、発泡しても泡もち性が良好ではなく、好ましくない。そのため、プレポリマー（Ａ）と活性水素含有化合物（Ｂ）、水（Ｃ）及び／又はアミン系触媒（Ｄ）、整泡剤（Ｅ）と共に、加熱したシリンダー内に個々に供給して高速攪拌するか、プレポリマー（Ａ）の合成後に後添加して、プレポリマー（Ａ）と混合して供給することなどが好ましい。
【００３９】
本発明において、上記プレポリマー（Ａ）を使用するが、必要に応じて本来の湿気硬化性を損なわない範囲で使用時に活性水素を少なくとも２個有する化合物（Ｃ）を鎖伸長剤として使用することも出来る。
【００４０】
本発明で使用する活性水素を少なくとも２個有する化合物（Ｃ）としては、例えば、エチレングリコール、１，２−プロピレングリコール、１，３−プロピレングリコール、１，３−ブチレングリコール、１，４−ブチレングリコール、２，２−ジメチル−１，３−プロパンジオール、１，６−ヘキサンジオール、３−メチル−１，５−ペンタンジオール、１，８−オクタンジオール、ジエチレングリコール、トリエチレングリコール、ジプロピレングリコール、トリプロピレングリコール、シクロヘキサン−１，４−ジメタノール、ビスフェノールＡのＥＯまたはＰＯ付加物などの１種または２種以上のジオール等のグリコール、グリセリン、トリメチロールエタン、トリメチロールプロパン、ペンタエリスリトール等の多価アルコール、或いは前記ポリエステル系ポリオールを開始剤とするエチレンオキサイド、プロピレンオキサイド、ブチレンオキサイド、スチレンオキサイドなどの単独或いは２種以上の開環重合物、前記ポリエーテル系ジオールのγ−ブチロラクトン、ε−カプロラクトンなどの開環付加重合物等が使用出来る。又、エチレンジアミン、１，３−プロピレンジアミン、１，２−プロピレンジアミン、ヘキサメチレンジアミン、ノルボルネンジアミン、ヒドラジン、ピペラジン、Ｎ，Ｎ’−ジアミノピペラジン、２−メチルピペラジン、４，４’−ジアミノジシクロヘキシルメタン、イソホロンジアミン、ジアミノベンゼン、ジフェニルメタンジアミン、メチレンビスジシクロアニリン、トリエチレンジアミン、テトラメチルヘキサメチレンジアミン、トリエチルアミン、トリプロピルアミン、トリメチルアミノエチルピペラジン、Ｎ−メチルモルフォリン、Ｎ−エチルモルフォリン、ジ（２，６−ジメチルモルフォリノエチル）エーテルなどのポリアミン、及び１種及び２種以上の混合物を使用できる。しかし、加工時のイソシアネート基との反応が緩やかであり架橋速度の制御が行い易い点から加工適性を考慮した場合に、グリコールが好ましい。加工性を損なわない範囲であれば、ウレタン樹脂の原料として使用される上記ポリアミンの単独使用や上記ポリオールとの併用は、特に制限されるものでない。
【００４１】
次に、本発明で使用する水（Ｄ）は、発泡剤として作用する必須成分である。プレポリマー（Ａ）と水（Ｄ）との反応により、炭酸ガスが発生して本発明の目的である発泡体が生成するが、水（Ｄ）の使用量は、炭酸ガスの発生過多による発泡体の厚みむらや面状態の不良発生、あるいはゲル化による加工性の低下等が起こらない範囲で選択されることが好ましい。
【００４２】
本発明で使用する水（Ｄ）は、プレポリマー（Ａ）とポリイソシアネート成分（Ｂ）と活性水素を少なくとも２個有する化合物（Ｃ）を加熱溶融した状態で、混合攪拌して水で発泡させるための必須成分であり、場合によっては、アミン触媒（Ｅ）、整泡剤（Ｆ）を加えてもよい。プレポリマー（Ａ）とポリイソシアネート成分（Ｂ）と活性水素を少なくとも２個有する化合物（Ｃ）のみの場合では、溶融粘度は上昇するが、水で発泡するのに必要な水が不足しており発泡しにくく、また、プレポリマー（Ａ）とポリイソシアネート成分（Ｂ）と水（Ｄ）のみの場合では、発泡は若干するが、発泡した後の溶融粘度が急激に上昇しないため泡が潰れてしまい、泡の固定化が困難である。そのため、本発明では、プレポリマー（Ａ）とポリイソシアネート成分（Ｂ）と活性水素を少なくとも２個有する化合物（Ｃ）と水（Ｄ）の組合せが、溶融粘度の上昇による泡の固定化と水による発泡性のバランスに優れており、場合によりアミン系触媒（Ｅ）、整泡剤（Ｆ）を加えることにより更に良好となる。
【００４３】
上記の活性水素を少なくとも２個有する化合物（Ｃ）及び水（Ｄ）の添加量は、プレポリマー（Ａ）及びポリイソシアネート成分（Ｂ）の総ＮＣＯ基が、活性水素を少なくとも２個有する化合物（Ｃ）及び水（Ｄ）と反応した後の、仕込総重量「（Ａ）＋（Ｂ）＋（Ｃ）＋（Ｄ）」に対する残存ＮＣＯ基含有率が、好ましくは１．５〜９．０重量％の範囲であればよく、より好ましくは２．０〜８．０重量％の範囲である。活性水素を少なくとも２個有する化合物（Ｃ）及び水（Ｄ）の添加量がかかる範囲であれば、良好な増粘効果が得られ、泡もち性が良好であり、また混合攪拌時にゲル化することもなく、好ましい。
【００４４】
また、本発明で使用する活性水素を少なくとも２個有する化合物（Ｃ）と水（Ｄ）の反応基当量の比［反応基当量（ｃ）／反応基当量（ｄ）］が０．５〜１０．０の範囲であり、より好ましくは１．０〜５．０の範囲である。
【００４５】
尚、水（Ｄ）の添加量は、上記プレポリマー（Ａ）及びポリイソシアネート成分（Ｂ）の総ＮＣＯ基が、活性水素を少なくとも２個有する化合物（Ｃ）及び水（Ｄ）と反応した後の残存ＮＣＯ基含有率が、１．５〜９．０重量％の範囲において、上記プレポリマー（Ａ）とポリイソシアネート成分（Ｂ）の総重量が１００重量部に対して、好ましくは０．０５〜５．０重量部、より好ましくは０．１〜２．０重量部とすることができる。水（Ｄ）の添加量がかかる範囲であれば、発泡度が適度となり発泡体の表面状態が良好となり、好ましい。
【００４６】
本発明の無溶剤型湿気硬化性ホットメルトウレタン樹脂組成物には、上記プレポリマー（Ａ）、ポリイソシアネート成分（Ｂ）、活性水素を少なくとも２個有する化合物（Ｃ）、及び水（Ｄ）を必須成分とする他に、加熱溶融した状態で、ウレタン化触媒、整泡剤等を混合攪拌することが好ましく、それぞれの単独若しくは２種以上を添加することが出来る。
【００４７】
本発明で使用するウレタン化触媒としては、例えば、アミン系触媒、有機金属系触媒、アミジン系触媒などをあげることができ、好ましくはアミン系触媒（Ｅ）である。
【００４８】
本発明で使用するアミン系触媒（Ｅ）としては、触媒定数の比であるＫＷ_２／ＫＷ_１が、０．５以上のアミン系触媒であることが好ましい。尚、本発明において、ＫＷ_２は水とトリレンジイソシアネート（ＴＤＩ）との反応の重量当たりの触媒定数であり、ＫＷ_１はジエチレングリコール（ＤＥＧ）とトリレンジイソシアネート（ＴＤＩ）との反応の重量当たりの触媒定数を表すものとする。
【００４９】
かかるアミン系触媒（Ｅ）の触媒定数であるＫＷ_１及びＫＷ_２は、下記のポリウレタンの生成反応式（１）及び（２）の反応速度の測定により得られる定数である。
反応式（１）　ＲＮＣＯ　＋Ｒ’ＯＨ→ＲＮＨＣ（＝Ｏ）ＯＯＲ’
反応式（２）２ＲＮＣＯ　＋Ｈ_２Ｏ→ＲＮＨＣ（＝Ｏ）ＮＨＲ＋ＣＯ_２
尚、反応速度の測定方法は、Ａ．Ｆａｒｋａｓの方法〔参考文献：Ｊ．Ａｍ．Ｃｈｅｍ．Ｓｏｃ．８２，６４２（１９６０）〕に従い、３０℃でのベンゼン溶液中で、水とＴＤＩの反応速度定数（Ｋ_２）と、ＤＥＧとＴＤＩの反応速度定数（Ｋ_１）を測定して、便宜上、重量当たりの触媒定数をそれぞれＫＷ_２及びＫＷ_１として表した。
【００５０】
本発明で使用するアミン系触媒（Ｅ）としては、例えば、Ｎ，Ｎ−ジメチルシクロヘキシルアミン（ＤＭＣＨＡ）、Ｎ−メチルジシクロヘキシルアミン（ＭＤＣＨＡ）、Ｎ，Ｎ，Ｎ’，Ｎ’−テトラメチルエチレンジアミン（ＴＭＥＤＡ）、Ｎ，Ｎ，Ｎ’，Ｎ’−テトラメチルプロピレンジアミン（ＴＭＰＤＡ）、Ｎ，Ｎ，Ｎ’，Ｎ’−テトラメチルヘキサメチレンジアミン（ＴＭＨＭＤＡ）、Ｎ，Ｎ，Ｎ’，Ｎ’’，Ｎ’’−ペンタメチルエチレンプロピレントリアミン（ＰＭＥＰＴＡ）、Ｎ，Ｎ，Ｎ’，Ｎ’’，Ｎ’’−ペンタメチルジプロピレンテトラアミン（ＰＭＤＰＴＡ）、Ｎ，Ｎ，Ｎ’，Ｎ’’，Ｎ’’’，Ｎ’’’−ヘキサメチルジプロピレンエチレンテトラアミン（ＨＭＡＰＥＤＡ）、Ｎ、Ｎ‘−ジメチルピペラジン（ＤＭＰ）、Ｎ，Ｎ，Ｎ’−トリメチル−Ｎ−アミノエチルピレラジン（ＴＭＮＡＥＰ）、Ｎ−メチルモルフォリン（ＮＭＭＯ）、Ｎ−ヒドロキシエチルモルフォリン（ＨＥＭＯ）、Ｎ，Ｎ，Ｎ’，Ｎ’−テトラメチルジプロピレンエチレングリコールジアミン（ＴＭＥＧＤＡ）、Ｎ、Ｎ、Ｎ’、Ｎ’’、Ｎ’’’、Ｎ’’’−ヘキサメチルテトラアミン（ＨＭＴＥＴＡ）、ジメチルアミノエチルエタノールエーテル（ＤＭＡＥＥ）、トリメチルアミノエチルエタノールアミン（ＴＭＡＥＥＡ）、ビスジメチルアミノエチルエーテル（ＢＤＭＥＥ）、トリエチルアミン（ＴＥＡ）、Ｎ，Ｎ，Ｎ’，Ｎ’’，Ｎ’’−ペンタメチルジエチレントリアミン（ＰＭＤＥＴＡ）等のアミン系触媒のうち、１種或いは２種類以上の混合物が使用できる。また、上記のアミン系触媒を必須成分とするなら、更に上記以外のウレタン化触媒或いは、有機金属系触媒、アミジン系触媒などを単独あるいは２種以上を併用してもよい。
【００５１】
かかるアミン系触媒（Ｅ）の使用量は、プレポリマー（Ａ）１００重量部に対して、好ましくは０．１〜１０重量部であり、より好ましくは０．５〜５重量部である。アミン系触媒（Ｅ）の使用量がかかる範囲であれば、良好な増粘効果が得られ、泡もち性が良好で、また、混合攪拌時にゲル化することもなく、好ましい。尚、必須成分であるアミン系触媒（Ｅ）と共に（Ｅ）以外の触媒を併用する場合は、アミン系触媒（Ｅ）と（Ｅ）以外の触媒との使用量合計は、プレポリマー（Ａ）１００重量部に対して、好ましくは０．１〜１０重量部であり、より好ましくは０．５〜５重量部である。
【００５２】
更に、本発明の無溶剤型湿気硬化性ホットメルトウレタン樹脂組成物には、必要に応じて本来の湿気硬化性を損なわない範囲で使用時に整泡剤（Ｆ）を使用することも出来る。かかる整泡剤（Ｆ）としては、例えば、有機珪素系界面活性剤などに使用される従来公知のポリシロキサン−ポリオキシアルキレン共重合体を含むものが好ましく、ポリシロキサン−ポリオキシアルキレン共重合体を１０重量％以上含むものがより好ましく、具体的には、東レダウコーニング・シリコーン株式会社製の商品名ＳＦ２９６９、ＰＲＸ６０７、ＳＦ２９６４、ＳＲＸ２７４Ｃ、ＳＦ２９６１、ＳＦ２９６２、ＳＦ２９６５、ＳＦ２９０８、ＢＹ１０−１２３、ＳＦ２９０４、ＳＲＸ２９４Ａ、ＢＹ１０−１２４、ＳＦ２９３５Ｆ、ＳＦ２９４５Ｆ、ＳＦ２９４４Ｆ、ＳＦ２９３６Ｆ、ＳＨ１９３、ＳＨ１９２Ｈ、ＳＨ１９２、ＳＦ２９０９、ＳＨ１９４、ＳＨ１９０、ＳＲＸ２９０Ａ、ＳＲＸ２９８、及び日本ユニカー株式会社製の商品名Ｌ−５８０、ＳＺ１１２７、ＳＺ１１１１、ＳＺ１１３６、ＳＺ１９１９、ＳＺ１１０５、ＳＺ１１４２、ＳＺ１１６２、Ｌ３６０１、Ｌ５３０９、Ｌ５３６６、ＳＺ１３０６、ＳＺ１３１１、ＳＺ１３１３、ＳＺ１３４２、Ｌ５３４０、Ｌ５４２０、ＳＺ１６０５、ＳＺ１６２７、ＳＺ１６４２、ＳＺ１６４９、ＳＺ１６７１、ＳＺ１６７５、ＳＺ１９２３などが挙げられる。
【００５３】
これら整泡剤（Ｆ）の使用量は、プレポリマー（Ａ）１００重量部に対して、好ましくは０．１〜２０重量部の範囲であり、より好ましくは０．５〜１０重量部の範囲である。整泡剤の使用量がかかる範囲であれば、整泡力に優れ、熟成後の発泡体の物理的機械強度にも優れる。
【００５４】
また、整泡剤（Ｆ）に、必要に応じてフタル酸ビス（２−エチルヘキシル）（ＤＯＰ）、アジピン酸ジイソノニル（ＤＩＮＡ）、アジピン酸ビス（２−エチルヘキシル）（ＤＯＡ）等の可塑剤、ＥＯ／ＰＯ共重合体等のポリエーテル系界面活性剤などを添加してもよい。
【００５５】
本発明の無溶剤型湿気硬化性ホットメルトウレタン樹脂組成物の架橋反応は、それぞれのプレポリマー中のイソシアネート基や加水分解性アルコキシシリル基が湿気と反応することにより起こる。
【００５６】
本発明の耐久性に優れた無溶剤型湿気硬化性ホットメルトウレタン樹脂組成物は、架橋反応性（即ち、湿気硬化性）とホットメルト性（即ち、常温では固形でありながら加熱により溶融して塗布可能な状態となり、冷却により再度凝集力が出る状態となる性質を云う）を併せ持つ樹脂組成物を云う。
【００５７】
本発明の無溶剤型湿気硬化性ホットメルトウレタン樹脂組成物の加工方法としては、例えば、プレポリマー（Ａ）を加熱して液状又は溶融状態とし、ポリイソシアネート成分（Ｂ）、活性水素を少なくとも２個有する化合物（Ｃ）、水（Ｄ）、及び／又はアミン系触媒（Ｅ）、整泡剤（Ｆ）と混合攪拌して、水で発泡させた後、ホットメルト性と湿気硬化性を利用して発泡状態を固定する方法が適している。また、発泡層のセルの形状を独泡状態から連通化状態まで制御する場合には、不活性気体を混合攪拌させることも可能である。
【００５８】
本発明の無溶剤型湿気硬化性ホットメルトウレタン樹脂組成物は、プレポリマー（Ａ）、ポリイソシアネート成分（Ｂ）、活性水素を少なくとも２個有する化合物（Ｃ）、水（Ｄ）の混合時に必要に応じて、活性水素を含有する鎖伸長剤、アミン系触媒（Ｅ）、整泡剤（Ｆ）、シランカップリング剤、粘着付与剤、架橋触媒、チキソ付与剤、ワックス、可塑剤、安定剤、充填剤、顔料、蛍光増白剤等の添加剤、熱可塑性樹脂等が単独若しくは２種以上添加されてもよい。
【００５９】
本発明でいう発泡層とは、人工皮革や合成皮革を構成する複層構造のうちの皮革としての風合いを付加する重要な層をいう。発泡層を得る方法としては、▲１▼ＤＭＦ溶剤を用いた湿式法、▲２▼発泡剤を用いた方法、▲３▼イソシアネートと水との反応により発生する炭酸ガスを利用する方法、▲４▼強制的なガス混入による機械発泡による方法等が知られている。
【００６０】
本発明の発泡体は、プレポリマー（Ａ）、ポリイソシアネート成分（Ｂ）、活性水素を少なくとも２個有する化合物（Ｃ）、及び水（Ｄ）からなる無溶剤型湿気硬化性ホットメルトウレタン樹脂組成物を加熱溶融した状態で混合撹拌し、水で発泡した後、湿気硬化せしめて得られることを特徴とする。また、本発明の発泡体は、プレポリマー（Ａ）、ポリイソシアネート成分（Ｂ）、活性水素を少なくとも２個有する化合物（Ｃ）、及び水（Ｄ）の他に、アミン系触媒（Ｅ）、整泡剤（Ｆ）などを含有する無溶剤型湿気硬化性ホットメルトウレタン樹脂組成物を加熱溶融した状態で混合撹拌し、水で発泡した後、湿気硬化せしめて得られるものであってもよい。
【００６１】
また、本発明の発泡体は、前記無溶剤型湿気硬化性ホットメルトウレタン樹脂組成物を加熱して液状又は溶融状態とし、必要に応じて予め不活性気体を混合して水で発泡させた後、ホットメルト性と湿気硬化性を利用して硬化させ、発泡状態を固定する方法が好ましい。不活性気体を混合した場合、水と不活性気体との熱膨張率の差が生じるため、混合比率により発泡セルの大きさが制御できるため有効である。
【００６２】
また、発泡層のセルの形状を独泡状態から連通化状態まで制御する場合には、不活性気体を混合撹拌させることも可能である。かかる不活性気体としては、例えば、窒素、希ガス、二酸化炭素、及びハロゲン化炭化水素等が挙げられる。
【００６３】
本発明の発泡体は、前述の無溶剤型湿気硬化性ホットメルトウレタン樹脂組成物を加熱溶融した状態で混合撹拌して、必要に応じて予め不活性気体を混合撹拌して、水で発泡した後、湿気硬化させて得られる。
【００６４】
かかる発泡体における泡（本発明では、セルとも云う）は、通常ほとんどのものが独泡（独立した泡）の状態であるが、一部に連通した泡（セル）が混在してもよい。その大きさは、適宜制御可能であるが、直径５．０〜２００μｍ程度が好ましい。又、発泡体の厚さは、特に制限されないものの、特に合成皮革や人工皮革に使用される場合には、厚さ０．０５〜１．０ｍｍ程度が好適である。かかる泡の大きさ及び発泡体の厚さは、後述するシート構造体に於ける本発明の無溶剤型湿気硬化性ホットメルトウレタン樹脂組成物から得られる発泡層にも適用される。
【００６５】
このようにして調製されるプレポリマー（Ａ）の数平均分子量は、特に限定はしないが、流動性や加工性などの面から、好ましくは５００〜５００，０００の範囲であり、より好ましくは１，０００〜１００，０００の範囲である。
【００６６】
プレポリマー（Ａ）を調製するに際して、必要ならば、ウレタン化触媒或いは安定剤等を使用することも出来る。これらの触媒や安定剤等は、斯かる反応の任意の段階で加えることが出来、特に制限はしない。
【００６７】
上記ウレタン化触媒としては、公知慣用の触媒が使用可能であり、例えば、酢酸カリウム、ステアリン酸亜鉛、又はオクチル酸錫などにより代表されるような種々の金属塩；あるいはジブチル錫ジラウレートなどにより代表されるような種々の有機金属化合物などが挙げられる。これらは単独使用でもよく、２種以上を併用してもよい。
【００６８】
また、上記安定剤としては、例えば、置換ベンゾトリアゾール類などのような紫外線に対する安定剤などであるし、更には置換フェノール誘導体などのような熱酸化に対する安定剤などが挙げられ、これらの各安定剤は、目的に応じて、適宜、選択して加えることが出来、単独使用でもよく、２種以上を併用してもよい。
【００６９】
また、加水分解性のアルコキシシリル基及びイソシアネート基を有するウレタンプレポリマー（ａ−２）の場合も、必要に応じて架橋触媒として、例えば、リンゴ酸、クエン酸等の各種の酸性化合物、水酸化リチウム、水酸化ナトリウム、水酸化カリウム、トリエチレンジアミン等の各種の塩基性化合物類、テトライソプロピルチタネート、ジ−ｎ−ブチル錫ジラウレート、ジ−ｎ−ブチル錫オキサイド、ジオクチル錫オキサイドまたはジ−ｎ−ブチル錫マレエート等の如き、各種の含金属化合物類等の一般的にアルコキシシリル基架橋触媒として用いられるものを添加して使用することが出来る。
【００７０】
上記シランカップリング剤としては、例えば、γ−グリシドキシプロピルトリメトキシシラン、γ−グリシドキシプロピルメチルジエトキシシラン、β−（３，４−エポキシシクロヘキシル）エチルトリメトキシシラン、γ−メタクリロキシプロピルトリメトキシシラン、γ−メルカプトプロピルトリメトキシシラン、ビニルトリメトキシシラン、又はγ−クロロプロピルトリメトキシシラン等が挙げられる。
【００７１】
上記充填材としては、例えば、炭酸カルシウム、硫酸バリウム、カオリン、タルク、カーボンブラック、アルミナ、酸化マグネシウム、無機・有機バルーン等が挙げられる。
【００７２】
また、上記チキソ付与剤としては、例えば、表面処理炭酸カルシウム、微粉末シリカ、ベントナイト、セピオライト等が挙げられる。特に発泡後の泡の安定化の点よりチキソ付与剤の添加は好ましい。
【００７３】
本発明のシート構造体は、上記の無溶剤型湿気硬化性ホットメルトウレタン樹脂組成物を加熱溶融した状態で混合撹拌し、水で発泡した後、湿気硬化せしめた発泡体を積層してなることを特徴とする。
【００７４】
本発明のシート構造体は、上記の無溶剤型湿気硬化性ホットメルトウレタン樹脂組成物を加熱溶融した状態で、予め不活性気体を混合撹拌し、水で発泡した後、湿気硬化せしめた発泡層を積層してなるものであってもよい。
【００７５】
本発明のシート構造体は、上記の無溶剤型湿気硬化性ホットメルトウレタン樹脂組成物を加熱溶融した状態で混合撹拌し、水で発泡した後、湿気硬化せしめた発泡体を積層し、更に皮革様のフィルム層を積層してなることを特徴とする。
【００７６】
本発明のシート構造体は、上記の無溶剤型湿気硬化性ホットメルトウレタン樹脂組成物を加熱溶融した状態で、予め不活性気体を混合撹拌し、水で発泡した後、湿気硬化せしめた発泡層を積層し、更に皮革様のフィルム層を積層してなるものであってもよい。
【００７７】
本発明のシート構造体は、皮革様のフィルムと該フィルム上に前記の無溶剤型湿気硬化性ホットメルトウレタン樹脂組成物を、水で発泡した後、硬化せしめた発泡層を有するものであってもよい。
【００７８】
本発明のシート構造体は、皮革様のフィルムと該フィルム上に前記の無溶剤型湿気硬化性ホットメルトウレタン樹脂組成物に、予め不活性気体を混合して、水で発泡した後、硬化せしめた発泡層を有するものであってもよい。
【００７９】
本発明の発泡体の発泡度は、その用途に応じて適宜調整することが出来、風合い或いは強度を損なわない範囲であれば、特に制限はない。例えば、人工皮革用途又は合成皮革用途であれば、通常、発泡度は１．５〜３．０倍の範囲が好ましい。尚、ここで云う「発泡度」とは、発泡前の樹脂の体積（Ｖ_１）と発泡後の樹脂の体積（Ｖ_２）の比［Ｖ_２／Ｖ_１］で表される。
【００８０】
本発明の無溶剤型湿気硬化性ホットメルトウレタン樹脂組成物とシート基材からシート構造体をもたらすことができる。即ち、シート基材上に前記樹脂組成物を加熱溶融状態で塗布し、水で発泡した後、湿気硬化させて発泡層を形成することによりシート構造体を得ることができる。勿論、該発泡層の上に更にシート基材を積層したシート構造体や、３枚以上のシート基材間に上記樹脂組成物による発泡層を一体化したシート構造体もできる。
【００８１】
本発明のシート構造体を構成するシート基材としては、例えば、不織布や織布、編布等の一般的に人工皮革や合成皮革に用いられている基布や天然皮革、各種プラスチックシート、フィルム、離型紙付きフィルム、離型紙、紙等であれば何ら限定されるものではない。また、前記基布に対して、溶剤系及び水系のポリウレタン樹脂、アクリル樹脂、ゴム系（ＳＢＲ、ＮＢＲなど）ラテックス等を少なくとも１種以上を含浸させた不織布や織布、編布等の一般的に人工皮革や合成皮革に用いられている基布や天然皮革等であれば何ら限定されるものではない。
【００８２】
本発明で使用するシート基材としてのフィルム及び離型紙付きフィルムは、従来、人工皮革用又は合成皮革用に用いられるポリウレタン樹脂が好ましく、通常溶剤系樹脂、水系樹脂、ホットメルト樹脂などを離型紙上に塗布乾燥して得ることが出来る。
【００８３】
本発明での発泡体及びシート構造体は、本発明の無溶剤型湿気硬化性ホットメルトウレタン樹脂組成物を加熱溶融した状態で、必要に応じて不活性気体を混合させて水で発泡させた発泡樹脂を、例えば離型紙間、又はシート基材と離型紙の間、又は基布と皮革様のフィルムの間、離型紙と撥水処理布及びフィルムとの間に、均一に積層し冷却固化させた後、架橋させて加工出来る方法であれば特に制限はない。また、かかる発泡体を調整後、シート基材又は／及び皮革様のフィルムと、溶剤系接着剤、水系接着剤、ホットメルト接着剤などを用いて接着加工してもよい。尚、該発泡体の発泡及び硬化を促進させるために、発泡体を貼り合わせた基材の基材表面又は発泡体表面、発泡体を一体化した構造体の基材表面又は発泡体表面に加湿処理を行ってもよい。
【００８４】
本発明の無溶剤型湿気硬化性ホットメルトウレタン樹脂組成物を発泡する設備は、必要に応じて不活性気体を所定量混合しながら均一混合可能な設備が望ましく、更に、不活性気体の混合時の攪拌で冷却増粘して均一な発泡が行われない場合や基材やフィルムに発泡層として加工した場合に流動せずに塗布不良や接着不良が起こることを避けるために混合物を加熱保温出来る構造が望ましい。
【００８５】
本発明での発泡体及びシート構造体を製造する際に、本発明の無溶剤型湿気硬化性ホットメルトウレタン樹脂組成物を加熱溶融し、水で発泡させるが、その際の加熱温度は、プレポリマー（Ａ）が溶融する温度以上であり、好ましくは６０〜２００℃の範囲である。加熱温度がかかる範囲であれば、該樹脂組成物の発泡の制御が容易であり、均質な発泡体が得られやすく、好ましい。
【００８６】
本発明での発泡体又はシート構造体を製造する装置としては、例えば、工業的にはプレポリマー（Ａ）を加熱溶融するタンクと水や他の添加剤などの貯蔵供給用タンク、各タンクからのそれぞれ材料を混合する槽、離型紙やシート基材を連続的に搬送するベルト、該ベルト上に溶融した樹脂組成物を供給するノズル、発泡体を硬化するための加湿室、必要により加熱室、他のシート基材供給部などからなるものである。上述の装置は、代表的なものであり、種々変更した他のものでも差し支えない。
【００８７】
尚、不活性気体を併用して本発明の樹脂組成物を発泡する場合の設備については、不活性気体を所定量混合しながら均一混合可能な設備であれば特に制限はないが、不活性気体の混合時の撹拌で冷却増粘して均一な発泡が行われない場合や基材及びフィルム、シートに発泡体として加工した場合に流動せずに塗布不良や接着不良が起こることを避けるために混合物を加熱保温出来る構造が望ましい。
【００８８】
本発明で得られる発泡体又はシート構造体への公知慣用のラミネート又はコーティング等による表面加工、或いはバフィング加工等の諸々の加工方法については何ら限定されるものではない。
【００８９】
以上のように、本発明により、特に接着性と発泡性、耐久性（特に、耐加水分解性、耐熱性）に優れる無溶剤型湿気硬化性ホットメルトウレタン樹脂組成物と、該ウレタン樹脂組成物を用いて得られる発泡体、それを用いたシート構造体、及び該シート構造体の製造方法を提供出来る。
【００９０】
本発明の無溶剤型湿気硬化性ホットメルトウレタン樹脂組成物、及びそれを用いた発泡体、シート構成体は、例えば、靴、家具、衣料、自動車などの車両、鞄、ケース等に用いる合成皮革や人工皮革以外にも、接着剤、粘着剤、シーリング剤、塗料、コーティング剤、フィルム、シート、断熱材、保温材、吸音材、クッション材、滑り止め、研磨パッド、電子電器材料、建材、土木、医療部材等々の幅広い用途において、極めて実用性が高い。
【００９１】
【実施例】
以下に、本発明を実施例により具体的に説明するが、本発明は、これらの実施例のみに限定されるものではない。尚、以下において、部及び％は、特にことわりのない限り、全て重量基準であるものとする。又、各種特性は以下の方法に従い測定した。
【００９２】
［表皮フィルム１の作製方法］
合成皮革表皮用の溶剤型ウレタン樹脂であるクリスボンＮＹ３２４（大日本インキ化学工業株式会社製）に、顔料のＤＩＬＡＣ−６００１（大日本インキ化学工業株式会社製）とメチルエチルケトン（ＭＥＫ）とジメチルホルムアミド（ＤＭＦ）とを混合撹拌してナイフコーターを用いて、離型紙上に塗布量が１００ｇ／ｍ^２（ｗｅｔ）になるように均一に塗布した後、７０℃で１分間乾燥後、次いで１２０℃で２分間乾燥させて、厚さ３０μｍの表皮フィルム１を作製した。
【００９３】
［軟化点の測定方法］
実施例及び比較例で得た各プレポリマーの軟化点を示差熱測定装置（ＤＳＣ、マックサイエンス社製）を用いて、窒素雰囲気下、昇温速度５℃／分にて測定した。
【００９４】
［接着性の測定方法］
温度２３℃、相対湿度６５％の環境下で５日間放置した表皮フィルム付きシート構造体の表皮フィルム１に布ホットメルトテープを１３０℃で５秒間熱圧着した後、２００ｍｍ／分のヘッドスピードにてＪＩＳ　Ｋ６３１１に準じて、テンシロンを用いて剥離強度を測定し、接着性の評価を行った。
【００９５】
［耐加水分解性の測定方法］
表皮フィルム付きシート構造体を耐加水分解試験（ジャングル試験条件：７０℃、相対湿度９５％、１２週間保持）に供した後、上記の接着性の評価方法と同様に剥離強度を測定して、保持率と、評価後の外観変化を観察し、下記の判定基準に従い評価した。
○：ジャングル試験後の外観変化無し。
×：ジャングル試験後の外観変化有り。
【００９６】
［耐熱性の測定方法］
表皮フィルム付きシート構造体を耐熱試験（試験条件：１２０℃、５００時間保持）に供した後、上記の接着性の評価方法と同様に剥離強度を測定して、保持率と、評価後の外観変化を観察し、下記の判定基準に従い評価した。
○：試験後の外観変化無し。
×：試験後の外観変化有り。
【００９７】
《実施例１》表皮フィルム付きシート構造体１の製造方法
１リットル４ツ口フラスコに数平均分子量が１４００なるポリテトラメチレングリコール（以下、ＰＴＭＧ１４００と略称）の７０部と、アジピン酸（表中ではＡＡと略称）とヘキサンジオール（表中ではＨＧと略称）との数平均分子量が２０００のポリエステルポリオール（表中ではポリエステルポリオール２０００と記載）の３０部を１２０℃に減圧加熱して、水分０．０５％となるまで脱水した。４０℃に冷却後、４，４’−ジフェニルメタンジイソシアネート（ＭＤＩ）を、表１中に示したＮＣＯ含有率（重量％）（以下、ＮＣＯ％と略記）になるように加えた後、９０℃まで昇温して、ＮＣＯ％が一定となるまで３時間反応してプレポリマー１を得た。コーンプレート粘度計での１２５℃の粘度は７０００ｍＰａ・ｓであった。得られたプレポリマー１を１２０℃に加熱して溶融して１２０℃で加温しながら、プレポリマー１の１００部に対して、ＭＤＩを表１に示した総ＮＣＯ基含有率（重量％）になるように、エチレングリコール（ＥＧ）を１．０部、ＰＯＬＹＣＡＴ−８［エアープロダクツジャパン社製；Ｎ，Ｎ−ジメチルシクロヘキシルアミン（ＤＭＣＨＡ）、触媒定数の比；ＫＷ_２／ＫＷ_１＝３．７３］を０．１０部、及び水を０．１２部と共に加えてミキシングして、約２．８倍に発泡したことを体積から確認した。直ちに、表皮フィルム１の上に厚み５０μｍで塗布して、ポリウレタン含浸不織布と貼り合せて冷却して、温度２３℃、相対湿度６５％の環境下で５日間放置して、シート状の表面フィルム付き構造体１を得た。本発明のシート状の表皮フィルム付き構造体１の特性評価結果を表１に示したが、発泡性、接着性、耐熱性、及び耐加水分解性に優れていた。
【００９８】
《実施例２》表面フィルム付きシート構造体２の製造方法
１リットル４ツ口フラスコに実施例１で得られたプレポリマー１を１２０℃に加熱して溶融して１２０℃で加温しながら、プレポリマー１の１００部に対して、ＭＤＩを表１に示した総ＮＣＯ基含有率になるように、ＥＧを１．０部、ＰＯＬＹＣＡＴ−８を０．１０部、及び水を０．１２部と共に加えてミキシングして、約３．０倍に発泡したことを体積から確認した。直ちに、表皮フィルム１の上に厚み５０μｍで塗布してポリウレタン含浸不織布と貼り合せて冷却して、温度２３℃、相対湿度６５％の環境下で５日間放置し、シート状の表皮フィルム付きシート構造体２を得た。本発明のシート状の表皮フィルム付きシート構造体２の特性評価結果を表１に示したが、発泡性、接着性、耐熱性、及び耐加水分解性に優れていた。
【００９９】
《実施例３》表面フィルム付きシート構造体３の製造方法
１リットル４ツ口フラスコにＰＴＭＧ１４００の７０部と、ポリエステルポリオール２０００の３０部を１２０℃に減圧加熱して、水分０．０５％となるまで脱水した。４０℃に冷却後、４，４’−ジフェニルメタンジイソシアネート（ＭＤＩ）を、表１中に示したＮＣＯ含有率（重量％）になるように加えた後、９０℃まで昇温して、ＮＣＯ％が一定となるまで３時間反応してプレポリマー２を得た。コーンプレート粘度計での１２５℃の粘度は９０００ｍＰａ・ｓであった。得られたプレポリマー２を１２０℃に加熱して溶融して１２０℃で加温しながら、プレポリマー２の１００部に対して、ＭＤＩを表１に示した総ＮＣＯ基含有率になるように、ＥＧを０．１６部、ＰＯＬＹＣＡＴ−８を０．１０部、及び水を０．１０部と共に加えてミキシングして、約２．５倍に発泡したことを体積から確認した。直ちに、表皮フィルム１の上に厚み５０μｍで塗布して、ポリウレタン含浸不織布と貼り合せて冷却して、温度２３℃、相対湿度６５％の環境下で５日間放置して、シート状の表面フィルム付き構造体３を得た。本発明のシート状の表皮フィルム付き構造体３の特性評価結果を表１に示したが、発泡性、接着性、耐熱性、及び耐加水分解性に優れていた。
【０１００】
《実施例４》表面フィルム付きシート構造体４の製造方法
実施例１で得られたプレポリマー１を、１２０℃に加熱溶融した後、１２０℃に加熱した数平均分子量が１０００のプロピレングリコール（以下、ＰＰＧ１０００と記載）と、ＭＤＩを表１に示した総ＮＣＯ基含有率になるように、ジブチルジ錫ジラウレート（ＤＢＳＮＤＬ）を、（プレポリマー１＋ＭＤＩ）／ＰＰＧ１０００／ＤＢＳＮＤＬ＝１００／３．０／０．１重量比で混合しながら、ＥＧを１．０部、ＰＯＬＹＣＡＴ−８を０．１０部、及び水０．１２部を共に加えてミキシングして、約２．８倍に発泡したことを体積から確認した。発泡プレポリマー３を得た。直ちに、表皮フィルム１の上に厚み５０μｍで塗布して、ポリウレタン含浸不織布と貼り合せて冷却して、温度２３℃、相対湿度６５％の環境下で５日間放置して、シート状の表皮フィルム付きシート構造体４を得た。本発明のシート状の表面フィルム付きシート構造体４の特性評価結果を表１に示したが、発泡青、接着性、耐熱性、及び耐加水分解性に優れていた。
【０１０１】
《比較例１》
１リットル４ツ口フラスコに実施例１で得られたプレポリマー１を１２０℃に加熱して溶融して１２０℃で加温しながら、プレポリマー１の１００部に対して、ＥＧを１．３０部、ＰＯＬＹＣＡＴ−８を０．１０部、及び水０．１５部を加えてミキシングして、約１．０倍に発泡したことを体積から確認した。直ちに、表皮フィルム１の上に厚み５０μｍで塗布してポリウレタン含浸不織布と貼り合せて冷却して、温度２３℃、相対湿度６５％の環境下で５日間放置して、シート状の表面フィルム付きシート構造体５を得た。その特性評価結果を表２に示す。本品は、発泡性及び耐熱性に劣るものであった。
【０１０２】
《比較例２》
１リットル４ツ口フラスコに実施例３で得られたプレポリマー２を１２０℃に加熱して溶融して１２０℃で加温しながら、プレポリマー２の１００部のみをミキシングしたが、約１．０倍と殆ど発泡しなかったことを体積から確認した。直ちに、表皮フィルム１の上に厚み５０μｍで塗布してポリウレタン含浸不織布と貼り合せて冷却して、温度２３℃、相対湿度６５％の環境下で５日間放置して、シート状の表面フィルム付きシート構造体６を得た。その特性評価結果を表２に示した。本品は、発泡性及び耐熱性に劣るものであった。
【０１０３】
【表１】

【０１０４】
【表２】

【０１０５】
【発明の効果】
本発明の無溶剤型湿気硬化性ホットメルトウレタン樹脂組成物は、イソシアネート基含有ホットメルトウレタンプレポリマー（Ａ）、ポリイソシアネート成分（Ｂ）、活性水素を少なくとも２個有する化合物（Ｃ）、及び水（Ｄ）からなる樹脂組成物であり、発泡性、接着性及び耐久性（特に、耐熱性、耐加水分解性）に優れる。本発明の樹脂組成物を加熱溶融した状態で混合撹拌し、水で発泡した後、湿気硬化させることにより発泡体を得ることができ、及びそれを用いたシート構造体は、例えば、靴、家具、衣料、自動車などの車両、鞄、ケース等に用いる合成皮革や人工皮革以外にも、接着剤、粘着剤、シーリング剤、塗料、コーティング剤、フィルム、シート、断熱材、保温材、吸音材、クッション材、滑り止め、研磨パッド、電子電器材料、建材、土木、医療部材等々の幅広い用途において、極めて実用性が高い。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a novel and useful solvent-free moisture-curable hot-melt urethane resin composition, a foam, a sheet structure using the same, and a method for producing the sheet structure.
[0002]
[Prior art]
Conventionally, polyurethane resins have been widely used for artificial leather and synthetic leather. Artificial leather or synthetic leather broadly refers to a sheet-like material obtained by combining a polyurethane resin composition with a nonwoven fabric, a woven fabric, a knitted fabric, and the like, but is generally classified as follows. Have been.
[0003]
That is, “artificial leather” refers to a sheet-like material in which a polyurethane resin composition is filled or laminated in a non-woven fabric, and is generally manufactured using dimethylformamide (hereinafter, also referred to as DMF) of a polyurethane resin composition. The nonwoven fabric is impregnated or coated with the solution, and the resulting solution is coagulated in a water coagulation bath or a coagulation bath composed of a mixed solution of DMF and water to coagulate the polyurethane resin to form a porous material, followed by washing and drying. It is obtained by a method of passing through a process, a so-called wet processing method.
[0004]
On the other hand, “synthetic leather” is generally roughly classified into dry synthetic leather and wet synthetic leather, and refers to a sheet-like material in which a polyurethane resin composition is laminated on a woven or knitted fabric. As a method for producing dry synthetic leather, generally, a DMF solution of a polyurethane resin composition is impregnated or coated with a woven or knitted fabric, and the resultant is subjected to a water coagulation bath or a coagulation bath comprising a mixed solution of DMF-water. It is obtained by a so-called wet processing method in which a polyurethane resin is coagulated to form a porous material and then subjected to a washing step and a drying step. As a method for producing dry synthetic leather, a polyurethane resin and a pigment, a solvent, and an additive are mixed and stirred to prepare a coating resin solution for a skin, and then applied on a release paper that has been shaped and the solvent is dried. After applying a two-component polyurethane resin adhesive to the release paper and laminating it to a base cloth such as a brushed cloth, the solvent is dried and then aged to form various skins without forming a porous layer. It refers to a method of manufacturing a multilayered processed body for leather by laminating a decorative film on a base cloth.
[0005]
Since these processing methods use solvent-type urethane resin, drying and extraction of the solvent are indispensable during the processing step, so that there is a problem of adverse effects on the human body, environmental pollution, and evaporation of the solvent. Recently, there has been an increasing demand for a shift from a solvent type resin to a solventless type resin or a shift to a solventless type processing method.
[0006]
A water-based method has been studied as a solvent-free method, but its practical use is limited due to poor water resistance and durability. In addition, in the case of a solvent-free liquid crosslinked resin, since the expression of cohesive force depends on crosslinkage, it is difficult to adjust the cohesive force at the time of processing such as coating and bonding, which makes application to synthetic leather processing difficult.
[0007]
Further, a “solvent-free moisture-curable (reactive) hot-melt urethane resin composition” which is used for adhesives and coating materials by heating and melting a solid reactive resin at room temperature is well known. Conventionally, as an example of foaming a reactive hot melt urethane resin composition, a method of introducing an inert gas under pressure into a reactive hot melt urethane resin composition in a molten state (Japanese Unexamined Patent Publication No. Hei 3-6281, published in Europe) Patent No. 405,721) is disclosed, but if the composition is not pressurized and released to ambient pressure, the state of the foam is inhomogeneous and the cell shape and mechanical strength are insufficient. There is a disadvantage that.
[0008]
Further, there has been a demand for the development of a reactive hot melt urethane resin composition having excellent properties such as foamability, adhesiveness, and durability (in particular, hydrolysis resistance and heat resistance).
[0009]
[Problems to be solved by the invention]
An object of the present invention is to provide a solvent-free moisture-curable hot based on a moisture-curing reaction, which provides a high-performance porous layer having excellent adhesiveness, foaming properties and durability (in particular, hydrolysis resistance and heat resistance). An object of the present invention is to provide a melt urethane resin composition, a foam, a sheet structure using the same, and a method for producing the sheet structure.
[0010]
[Means for Solving the Problems]
The present invention provides an isocyanate group-containing hot melt urethane prepolymer (A) having a softening point in the range of 30 to 160 ° C. [hereinafter referred to as prepolymer (A)], a polyisocyanate component (B), and at least two active hydrogens. Compound (C) and water (D) as essential components, and a total isocyanate group content of 2.0 to 10.0% by weight based on the total weight of the prepolymer (A) and the polyisocyanate component (B). A solvent-free moisture-curable hot melt urethane resin composition is provided.
[0011]
Further, the present invention provides a foam obtained by mixing and stirring the solvent-free moisture-curable hot-melt urethane resin composition in a state where the composition is heated and melted, foaming with water, and then moisture-curing. To do.
[0012]
Further, the present invention provides a sheet structure characterized by laminating the foam on a sheet substrate.
[0013]
Further, the present invention provides a sheet structure characterized by laminating the foam on a sheet substrate and further laminating a leather-like film layer.
[0014]
Further, the present invention also provides a sheet structure that is obtained by mixing and stirring the solvent-free moisture-curable hot melt urethane resin composition on a sheet substrate while being heated and melted, foaming with water, and then moisture-curing. It is intended to provide a manufacturing method.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Necessary items for implementing the present invention will be described below.
[0016]
In the present invention, a prepolymer (A), preferably an isocyanate group-terminated urethane prepolymer having a softening point in the range of 30 to 160 ° C, a prepolymer (A) containing an alkoxysilyl group-terminated urethane prepolymer if necessary, a polyisocyanate component (B), a compound (C) having at least two active hydrogens and water (D), and a total isocyanate group content relative to the total weight of the prepolymer (A) and the polyisocyanate component (B) is 2. The solvent-free moisture-curable hot-melt urethane resin composition characterized by being in the range of 0 to 10.0% by weight is heated and melted, mixed, stirred and foamed with water, and then subjected to a moisture curing reaction. By forming a foam based on this, it is possible to obtain a uniform cell shape in addition to excellent adhesiveness and durability (in particular, hydrolysis resistance and heat resistance). And high performance of solvent-free porous layer is obtained moisture-curable hot-melt urethane resin composition having both a foamable that the foam using the same, and the sheet structure is obtained.
[0017]
First, the prepolymer (A) which is a main component of the solventless moisture-curable hot melt urethane resin composition will be described.
[0018]
The prepolymer (A) used in the present invention is an isocyanate group-terminated urethane prepolymer (a-1) in which an isocyanate group obtained by a reaction between a polyol component and an isocyanate component is left, or a polyol component and a polyisocyanate component. Prepolymer having a hydrolyzable alkoxysilyl group and an isocyanate group obtained by reacting a compound having at least one active hydrogen atom per molecule with an isocyanate group per molecule and having a hydrolyzable silyl group (A-2), preferably in combination with an isocyanate group-terminated urethane prepolymer (a-1) or a urethane prepolymer having a hydrolyzable alkoxysilyl group and an isocyanate group (a-2). It is made.
[0019]
The isocyanate group-terminated urethane prepolymer (a-1) has a polyol component and a polyisocyanate component in which the equivalent ratio of the NCO group of the isocyanate to the hydroxyl group of the polyol (NCO group / hydroxyl group equivalent ratio) exceeds 1, that is, the NCO group Is obtained by reacting in excess. The equivalent ratio of NCO group / hydroxyl group is usually preferably in the range of 1.1 to 5.0, more preferably in the range of 1.5 to 3.0.
The isocyanate group content in the urethane prepolymer (A) is usually preferably in the range of 1.5 to 8.0% by weight.
If the equivalent ratio of NCO group / hydroxyl group and the isocyanate group content in the urethane prepolymer (A) are within the above ranges, excellent processability, foaming property, and appropriate crosslinking density can be obtained.
[0020]
The urethane prepolymer (a-2) having a hydrolyzable alkoxysilyl group and an isocyanate group has at least one active hydrogen atom per molecule that reacts with the polyol component, the polyisocyanate component, and the isocyanate group. And a compound having a hydrolyzable silyl group. Usually, a compound having both a functional group capable of reacting with an isocyanate group and a hydrolyzable silyl group is reacted with the above-mentioned polyurethane prepolymer having an isocyanate group, so that a hydrolyzable silyl group is provided at a molecular terminal. The method of introducing is used. In addition, by reacting a polyurethane prepolymer having an isocyanate group with a compound having at least two functional groups capable of reacting with the isocyanate group and a hydrolyzable silyl group, the isocyanate group and the hydrolyzable Is obtained.
[0021]
Examples of the polyol component constituting the prepolymer (A) used in the present invention include polyester-based polyols, polyether-based polyols, polycarbonate-based polyols, and mixtures or copolymers thereof. Further, acrylic polyols, polyolefin-based polyols, lactone-based polyols, castor oil-based polyols, polyhydric alcohols, and the like, or mixtures or copolymers thereof, may be used.
[0022]
Examples of the polyester-based polyol include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, and 2,2-dimethyl-1,3- Propanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8-octanediol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, cyclohexane-1,4-diol, One or more diols such as cyclohexane-1,4-dimethanol, EO or PO adduct of bisphenol A, and succinic acid, maleic acid, adipic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, Sebacic acid, phthalic acid, Sofutaru acid, terephthalic acid, one or condensates of two or more dicarboxylic acids such as hexahydroisophthalic acid and the like. Other examples include ring-opening polymers such as γ-butyrolactone and ε-caprolactone using the above-mentioned glycol component as an initiator. In the present invention, EO means ethylene oxide, and PO means propylene oxide.
[0023]
Examples of the polyether polyol include, for example, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 2,2-dimethyl-1, 3-propanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8-octanediol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, cyclohexane-1,4- Glycol components such as diols and cyclohexane-1,4-dimethanol, or polyhydric alcohols such as glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol; Side, propylene oxide, butylene oxide, alone or ring-opening polymerization product of styrene oxide, and the like. Further, ring-opening addition polymers such as γ-butyrolactone and ε-caprolactone to these polyether-based diols may be mentioned.
[0024]
Further, known low molecular weight polyols can also be used. For example, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 2,2- Dimethyl-1,3-propanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8-octanediol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, cyclohexane- One or more diols such as 1,4-diol, cyclohexane-1,4-dimethanol, and an EO or PO adduct of bisphenol A are exemplified.
[0025]
The polyisocyanate component that can be used for the prepolymer (A) in the present invention is not particularly limited, but, for example, phenylene diisocyanate, tolylene diisocyanate (TDI), 4,4′-diphenylmethane diisocyanate, 2,4 -Diphenylmethane diisocyanate, aromatic diisocyanate such as naphthalene diisocyanate and hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate, aliphatic or alicyclic diisocyanate such as tetramethyl xylylene diisocyanate and the like. Can be These polyisocyanate components may be used alone or in combination of two or more. Among these, in consideration of being used for a hot melt urethane resin that is used by melting, it is preferable to use diphenylmethane diisocyanate (MDI) having a low vapor pressure during heating.
[0026]
The urethane prepolymer (a-2) having a hydrolyzable alkoxysilyl group and an isocyanate group used in the present invention has at least one active hydrogen atom per molecule that reacts with the isocyanate group, and The compound having a decomposable silyl group is particularly limited as long as it has at least one functional group having an active hydrogen atom that reacts with an isocyanate group per molecule and has a hydrolyzable silyl group. Not something. Examples of the functional group having an active hydrogen atom include an amino group, a hydroxyl group, and an SH group. Among them, an amino group is preferable from the viewpoint of excellent reactivity with an isocyanate group. On the other hand, examples of the hydrolyzable silyl group include silyl groups that are easily hydrolyzed, such as a halosilyl group, an alkoxysilyl group, an acyloxysilyl group, a phenoxysilyl group, an iminooxysilyl group, and an alkenyloxysilyl group. However, more specifically, those represented by the following general formula [1] can be mentioned.
[0027]
Embedded image

[0028]
(However, R in the general formula [1]₁を represents a hydrogen atom or a monovalent organic group selected from an alkyl group, an aryl group and an aralkyl group,₂Represents a halogen atom or an alkoxyl group, an acyloxy group, a phenoxy group, an iminooxy group or an alkenyloxy group, and n represents 0 or an integer of 1 or 2. )
[0029]
Among the above hydrolyzable silyl groups, a trimethoxysilyl group, a triethoxysilyl group, a (methyl) dimethoxysilyl group, a (methyl) diethoxysilyl group, and the like are preferable in that the crosslinking easily proceeds.
[0030]
Examples of the compound having a functional group capable of reacting with an isocyanate group and a hydrolyzable silyl group used in the present invention include γ- (2-aminoethyl) aminopropyltrimethoxysilane and γ- (2-hydroxyl Ethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropyltriethoxysilane, γ- (2-hydroxyethyl) aminopropyltriethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldiethoxysilane, γ- (2-hydroxylethyl) aminopropylmethyldimethoxysilane, γ- (2-hydroxylethyl) aminopropylmethyldiethoxysilane or γ- (N, N -Di-2-hydroxylethyl) aminopropyl Liethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, γ- (N-phenyl) aminopropyltrimethoxysilane, etc. Is mentioned.
[0031]
Furthermore, in the present invention, the prepolymer (A) may use two or more kinds of polyol components, and the types of the polyol component and the polyisocyanate component used in combination are not particularly limited.
[0032]
The softening point of the prepolymer (A) is preferably in the range of 30 to 160 ° C, more preferably in the range of 40 to 100 ° C. It is preferable that the softening point of the prepolymer (A) is in the above range, since a stable and uniform foam without unevenness can be obtained, and the cooling and solidifying time of the foamed cells foamed with water can be appropriately set.
[0033]
The method for adjusting the softening point of the prepolymer (A) used in the present invention is not particularly limited. For example, (1) an adjustment method based on the molecular weight (molar ratio of polyol component to polyisocyanate component, use of high molecular weight polyol) , The use of high-molecular polymers, etc.), (2) a method of adjusting the ethylene chain of the polyester-based polyol by crystallinity, (3) a method of adjusting the aromatic ring structure of the polyol component or the polyisocyanate component, and (4) a urethane bond. There are adjustment methods based on the amount.
[0034]
In order to prepare the prepolymer (A) used in the present invention, various known and commonly used methods may be used, and there is no particular limitation.
[0035]
Generally, in the case of an isocyanate group-terminated urethane prepolymer (a-1), a polyol component from which water has been removed is added dropwise to the raw material isocyanate component and heated to react until the hydroxyl group of the polyol component disappears. In the case of a urethane prepolymer (a-2) having a hydrolyzable alkoxysilyl group and an isocyanate group, the isocyanate group-terminated urethane prepolymer (a-1) obtained as described above reacts with an NCO group. It is obtained by dropping an alkoxysilane compound having a group represented by the formula below and, if necessary, reacting by heating. This reaction is carried out in the absence of a solvent, but may be carried out in an organic solvent in some cases, followed by removing the solvent. When the reaction is carried out in an organic solvent, various known organic solvents such as ethyl acetate, n-butyl acetate, methyl ethyl ketone, and toluene can be used, and the organic solvent is not particularly limited as long as it does not inhibit the reaction. In this case, after the reaction, it is necessary to remove the solvent by a desolvation method represented by heating under reduced pressure.
[0036]
Next, the polyisocyanate component (B) used in the present invention includes, for example, aromatic compounds such as phenylene diisocyanate, tolylene diisocyanate (TDI), 4,4′-diphenylmethane diisocyanate, 2,4-diphenylmethane diisocyanate, and naphthalene diisocyanate. One or two polyisocyanate components such as aliphatic or alicyclic diisocyanates such as diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate, and tetramethyl xylylene diisocyanate. Mixtures of the above can be used. Among these, it is preferable to use a polyisocyanate having a low vapor pressure at the time of heating in consideration of being used for a hot melt urethane resin composition to be used by melting. Among such polyisocyanates, diphenylmethane diisocyanate (MDI) It is particularly preferred to use
[0037]
The amount of the polyisocyanate component (B) used is such that the total NCO group content based on the total weight of the prepolymer (A) and the polyisocyanate component (B) is preferably in the range of 2.0 to 10.0% by weight. And more preferably in the range of 2.5 to 8.0% by weight. When the amount of the polyisocyanate component (B) used is in such a range, good foaming properties and durability (particularly, heat resistance and hydrolysis resistance) due to improvement in crosslink density become favorable.
[0038]
As a method of adding the polyisocyanate component (B), if the polyisocyanate component (B) in the above range is added before the addition of the polyisocyanate in the synthesis of the prepolymer (A), the molecular weight of the prepolymer (A) becomes large. Therefore, the foam does not exhibit initial cohesive strength, has poor foam stickiness even when foamed, and is not preferred. Therefore, the prepolymer (A), the active hydrogen-containing compound (B), the water (C) and / or the amine catalyst (D), and the foam stabilizer (E) are individually supplied into a heated cylinder and rapidly stirred. Alternatively, it is preferable to add after the synthesis of the prepolymer (A) and to mix and supply the prepolymer (A).
[0039]
In the present invention, the above prepolymer (A) is used, and if necessary, a compound (C) having at least two active hydrogens as a chain extender at the time of use is used as long as the original moisture curability is not impaired. Can also be.
[0040]
As the compound (C) having at least two active hydrogens used in the present invention, for example, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butylene glycol, 1,4-butylene Glycol, 2,2-dimethyl-1,3-propanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8-octanediol, diethylene glycol, triethylene glycol, dipropylene glycol, One or more diols such as tripropylene glycol, cyclohexane-1,4-dimethanol, and EO or PO adducts of bisphenol A, glycols such as glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol. Alcohol, Either ethylene oxide, propylene oxide, butylene oxide, singly or two or more ring-opening polymers such as styrene oxide using the polyester polyol as an initiator, γ-butyrolactone of the polyether diol, ε-caprolactone, etc. Ring-opening addition polymers and the like can be used. Also, ethylenediamine, 1,3-propylenediamine, 1,2-propylenediamine, hexamethylenediamine, norbornenediamine, hydrazine, piperazine, N, N′-diaminopiperazine, 2-methylpiperazine, 4,4′-diaminodicyclohexylmethane , Isophoronediamine, diaminobenzene, diphenylmethanediamine, methylenebisdicycloaniline, triethylenediamine, tetramethylhexamethylenediamine, triethylamine, tripropylamine, trimethylaminoethylpiperazine, N-methylmorpholine, N-ethylmorpholine, di ( Polyamines such as 2,6-dimethylmorpholinoethyl) ether, and one and more than one mixture can be used. However, glycols are preferred from the viewpoint of processing suitability because the reaction with isocyanate groups during processing is slow and the rate of crosslinking is easily controlled. The use of the above-mentioned polyamine used alone as a raw material of the urethane resin alone or in combination with the above-mentioned polyol is not particularly limited as long as the processability is not impaired.
[0041]
Next, water (D) used in the present invention is an essential component acting as a foaming agent. The reaction between the prepolymer (A) and the water (D) generates carbon dioxide to produce a foam which is the object of the present invention. It is preferable that the thickness be selected within a range that does not cause unevenness in the thickness of the body, poor surface condition, or deterioration in workability due to gelation.
[0042]
The water (D) used in the present invention is heated and melted in a state where the prepolymer (A), the polyisocyanate component (B), and the compound (C) having at least two active hydrogens are mixed and stirred to foam with water. In some cases, an amine catalyst (E) and a foam stabilizer (F) may be added. In the case of only the prepolymer (A), the polyisocyanate component (B) and the compound (C) having at least two active hydrogens, the melt viscosity increases, but the water necessary for foaming with water is insufficient. In the case where only the prepolymer (A), the polyisocyanate component (B) and the water (D) are used, foaming is slight, but the foam collapses because the melt viscosity after foaming does not increase rapidly. As a result, it is difficult to fix the foam. Therefore, in the present invention, the combination of the prepolymer (A), the polyisocyanate component (B), the compound (C) having at least two active hydrogens, and water (D) is effective in fixing the foam by increasing the melt viscosity, And the foamability is further improved by adding an amine catalyst (E) and a foam stabilizer (F) in some cases.
[0043]
The amount of the compound (C) having at least two active hydrogens and the amount of water (D) to be added are such that the total NCO groups of the prepolymer (A) and the polyisocyanate component (B) are compounds having at least two active hydrogens ( C) and the residual NCO group content with respect to the total weight “(A) + (B) + (C) + (D)” after reacting with water (D) is preferably 1.5 to 9.0. % By weight, more preferably from 2.0 to 8.0% by weight. When the amounts of the compound (C) having at least two active hydrogens and the water (D) are within the above ranges, a good thickening effect is obtained, foaming properties are good, and gelation occurs during mixing and stirring. None preferred.
[0044]
The ratio of the reactive group equivalent of the compound (C) having at least two active hydrogens used in the present invention to water (D) [reactive group equivalent (c) / reactive group equivalent (d)] is 0.5 to 10 0.0, more preferably in the range of 1.0 to 5.0.
[0045]
The amount of water (D) added is determined after the total NCO groups of the prepolymer (A) and the polyisocyanate component (B) have reacted with the compound (C) having at least two active hydrogens and water (D). When the residual NCO group content of the prepolymer (A) is 1.5 to 9.0% by weight, the total weight of the prepolymer (A) and the polyisocyanate component (B) is preferably 0.05 To 5.0 parts by weight, more preferably 0.1 to 2.0 parts by weight. When the amount of water (D) added is within such a range, the degree of foaming becomes appropriate and the surface state of the foam becomes good, which is preferable.
[0046]
The solvent-free moisture-curable hot-melt urethane resin composition of the present invention contains the prepolymer (A), the polyisocyanate component (B), the compound (C) having at least two active hydrogens, and water (D). In addition to the essential components, it is preferable to mix and stir a urethane-forming catalyst, a foam stabilizer and the like in a state of being heated and melted, and each of them can be used alone or in combination of two or more.
[0047]
Examples of the urethanization catalyst used in the present invention include an amine catalyst, an organometallic catalyst, an amidine catalyst, and the like, and an amine catalyst (E) is preferable.
[0048]
The amine catalyst (E) used in the present invention includes KW, which is a ratio of catalyst constants.₂/ KW₁Is preferably an amine catalyst of 0.5 or more. In the present invention, KW₂Is the catalytic constant per weight of the reaction of water with tolylene diisocyanate (TDI),₁Represents the catalytic constant per weight of the reaction of diethylene glycol (DEG) with tolylene diisocyanate (TDI).
[0049]
KW which is the catalytic constant of the amine catalyst (E)₁And KW₂Is a constant obtained by measuring the reaction rate in the following polyurethane formation reaction formulas (1) and (2).
Reaction formula (1) {RNCO} + R′OH → RNHC (＝ O) OOR ′
Reaction formula (2) 2RNCO + H₂O → RNHC (= O) NHR + CO₂
The method for measuring the reaction rate is described in A. The method of Farkas [Reference: J. et al. Am. Chem. Soc. 82, 642 (1960)], in a benzene solution at 30 ° C., the reaction rate constant (K₂) And the reaction rate constant of DEG and TDI (K₁) And, for convenience, the catalyst constant per weight₂And KW₁Expressed as
[0050]
Examples of the amine catalyst (E) used in the present invention include N, N-dimethylcyclohexylamine (DMCHA), N-methyldicyclohexylamine (MDCHA), N, N, N ′, N′-tetramethylethylenediamine ( TMEDA), N, N, N ′, N′-tetramethylpropylenediamine (TMPDA), N, N, N ′, N′-tetramethylhexamethylenediamine (TMHMDA), N, N, N ′, N ″ , N "-pentamethylethylenepropylenetriamine (PMEPTA), N, N, N ', N", N "-pentamethyldipropylenetetraamine (PMDPTA), N, N, N', N", N ′ ″, N ′ ″-hexamethyldipropyleneethylenetetraamine (HMAPEDA), N, N′-dimethylpiperazine (DM ), N, N, N'-trimethyl-N-aminoethylpyrazine (TMNAEP), N-methylmorpholine (NMMO), N-hydroxyethylmorpholine (HEMO), N, N, N ', N'- Tetramethyldipropylene ethylene glycol diamine (TMEGDA), N, N, N ', N ", N'", N '"-hexamethyltetraamine (HMMETA), dimethylaminoethylethanol ether (DMAEE), trimethyl Among amine catalysts such as aminoethylethanolamine (TMAEEA), bisdimethylaminoethylether (BDMEE), triethylamine (TEA), N, N, N ', N ", N" -pentamethyldiethylenetriamine (PMDETA) One or a mixture of two or more can be used. If the above-mentioned amine catalyst is an essential component, a urethanization catalyst other than the above, an organometallic catalyst, an amidine catalyst or the like may be used alone or in combination of two or more.
[0051]
The amount of the amine catalyst (E) to be used is preferably 0.1 to 10 parts by weight, more preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the prepolymer (A). When the amount of the amine catalyst (E) is within the above range, a good thickening effect is obtained, the foaming property is good, and no gelation occurs during mixing and stirring, which is preferable. When a catalyst other than (E) is used together with the amine catalyst (E), which is an essential component, the total amount of the amine catalyst (E) and the catalyst other than (E) is the same as that of the prepolymer (A). The amount is preferably 0.1 to 10 parts by weight, more preferably 0.5 to 5 parts by weight, per 100 parts by weight.
[0052]
Further, in the solvent-free moisture-curable hot melt urethane resin composition of the present invention, a foam stabilizer (F) can be used, if necessary, at the time of use as long as the original moisture curability is not impaired. As the foam stabilizer (F), for example, those containing a conventionally known polysiloxane-polyoxyalkylene copolymer used for an organic silicon-based surfactant or the like are preferable, and a polysiloxane-polyoxyalkylene copolymer is preferred. Is more preferably 10% by weight or more, and specifically, trade names SF2969, PRX607, SF2964, SRX274C, SF2961, SF2962, SF2965, SF2908, BY10-123, SF2904, SRX294A manufactured by Toray Dow Corning Silicone Co., Ltd. , BY10-124, SF2935F, SF2945F, SF2944F, SF2936F, SH193, SH192H, SH192, SF2909, SH194, SH190, SRX290A, SRX298, and Nippon Unicar Co., Ltd. Trade names L-580, SZ1127, SZ1111, SZ1136, SZ1919, SZ1105, SZ1142, SZ1162, L3601, L5309, L5366, SZ1306, SZ1311, SZ1313, SZ1342, L5340, L5420, SZ1605, SZ1627S1616S1616S1616S1616S1616 , SZ1923 and the like.
[0053]
The amount of the foam stabilizer (F) to be used is preferably in the range of 0.1 to 20 parts by weight, more preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the prepolymer (A). It is. If the amount of the foam stabilizer is within the above range, the foam stabilizer is excellent and the foam after aging has excellent physical mechanical strength.
[0054]
If necessary, a plasticizer such as bis (2-ethylhexyl) phthalate (DOP), diisononyl adipate (DINA), bis (2-ethylhexyl) adipate (DOA), or EO may be added to the foam stabilizer (F). A polyether-based surfactant such as a / PO copolymer may be added.
[0055]
The crosslinking reaction of the solvent-free moisture-curable hot-melt urethane resin composition of the present invention occurs when the isocyanate group or the hydrolyzable alkoxysilyl group in each prepolymer reacts with moisture.
[0056]
The solventless moisture-curable hot-melt urethane resin composition having excellent durability according to the present invention has a crosslinking reactivity (that is, moisture-curability) and a hot-melt property (that is, it is solid at normal temperature and melts by heating. A resin composition that is in a state where it can be applied and a state where cohesive force is generated again by cooling).
[0057]
As a method for processing the solvent-free moisture-curable hot-melt urethane resin composition of the present invention, for example, the prepolymer (A) is heated to a liquid or molten state, and the polyisocyanate component (B) and active hydrogen are mixed in at least 2 parts. After mixing with compound (C), water (D), and / or amine-based catalyst (E) and foam stabilizer (F), and foaming with water, hot melt properties and moisture curability are used. The method of fixing the foamed state by applying the heat treatment is suitable. When the shape of the cells of the foam layer is controlled from the closed cell state to the open state, it is possible to mix and stir an inert gas.
[0058]
The solvent-free moisture-curable hot-melt urethane resin composition of the present invention is required for mixing a prepolymer (A), a polyisocyanate component (B), a compound (C) having at least two active hydrogens, and water (D). Depending on the type, a chain extender containing an active hydrogen, an amine catalyst (E), a foam stabilizer (F), a silane coupling agent, a tackifier, a crosslinking catalyst, a thixotropic agent, a wax, a plasticizer, and a stabilizer A filler, a pigment, an additive such as a fluorescent brightener, a thermoplastic resin, or the like may be added alone or in combination of two or more.
[0059]
The foam layer referred to in the present invention refers to an important layer which adds a texture as leather in a multilayer structure constituting artificial leather or synthetic leather. Methods for obtaining a foamed layer include (1) a wet method using a DMF solvent, (2) a method using a foaming agent, (3) a method using carbon dioxide gas generated by a reaction between isocyanate and water, and (4). ▼ A method using mechanical foaming by forcible gas mixing is known.
[0060]
The foam of the present invention is a solventless moisture-curable hot melt urethane resin composition comprising a prepolymer (A), a polyisocyanate component (B), a compound (C) having at least two active hydrogens, and water (D). It is characterized in that it is obtained by mixing and stirring the product in a state of being heated and melted, foaming with water, and then curing with moisture. In addition, the foam of the present invention comprises, in addition to the prepolymer (A), the polyisocyanate component (B), the compound (C) having at least two active hydrogens, and water (D), an amine catalyst (E), A solvent-free moisture-curable hot-melt urethane resin composition containing a foam stabilizer (F) or the like may be obtained by mixing and stirring in a state of being heated and melted, foaming with water, and then moisture-curing. .
[0061]
Further, the foam of the present invention, after heating the solventless moisture-curable hot-melt urethane resin composition to a liquid or molten state, and optionally mixing an inert gas before foaming with water It is preferable to use a hot-melt property and a moisture-curing property to cure the composition to fix the foamed state. When an inert gas is mixed, a difference in the coefficient of thermal expansion between water and the inert gas occurs, which is effective because the size of the foam cell can be controlled by the mixing ratio.
[0062]
When the shape of the cells of the foam layer is controlled from the closed cell state to the communicating state, it is possible to mix and stir an inert gas. Examples of such an inert gas include nitrogen, a rare gas, carbon dioxide, and a halogenated hydrocarbon.
[0063]
The foam of the present invention was mixed and stirred in a state where the above-mentioned solvent-free moisture-curable hot melt urethane resin composition was heated and melted, and optionally mixed and stirred with an inert gas in advance, and foamed with water. Later, it is obtained by moisture curing.
[0064]
Most of the foams (also referred to as cells in the present invention) in such foams are usually closed cells (independent foams), but foams (cells) that are partially connected may be mixed. The size can be appropriately controlled, but the diameter is preferably about 5.0 to 200 μm. The thickness of the foam is not particularly limited, but is preferably about 0.05 to 1.0 mm particularly when used for synthetic leather or artificial leather. The size of the foam and the thickness of the foam are also applied to the foamed layer obtained from the solventless moisture-curable hot melt urethane resin composition of the present invention in the sheet structure described below.
[0065]
The number average molecular weight of the prepolymer (A) thus prepared is not particularly limited, but is preferably in the range of 500 to 500,000, more preferably 1 to 500, from the viewpoint of fluidity and processability. 000-100,000.
[0066]
In preparing the prepolymer (A), if necessary, a urethanization catalyst or a stabilizer may be used. These catalysts, stabilizers, and the like can be added at any stage of the reaction, and are not particularly limited.
[0067]
As the urethanization catalyst, known and commonly used catalysts can be used. For example, various metal salts such as potassium acetate, zinc stearate, and tin octylate; and dibutyltin dilaurate And various organometallic compounds. These may be used alone or in combination of two or more.
[0068]
Examples of the stabilizer include a stabilizer against ultraviolet rays such as substituted benzotriazoles and the like, and further, a stabilizer against thermal oxidation such as substituted phenol derivatives and the like. The agents can be appropriately selected and added according to the purpose, and may be used alone or in combination of two or more.
[0069]
Further, in the case of the urethane prepolymer (a-2) having a hydrolyzable alkoxysilyl group and an isocyanate group, various acidic compounds such as malic acid and citric acid, hydroxylation, etc. Various basic compounds such as lithium, sodium hydroxide, potassium hydroxide, triethylenediamine, tetraisopropyl titanate, di-n-butyltin dilaurate, di-n-butyltin oxide, dioctyltin oxide or di-n-butyl Those generally used as a catalyst for crosslinking an alkoxysilyl group, such as various metal-containing compounds such as tin maleate, can be added and used.
[0070]
Examples of the silane coupling agent include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-methacryloxy Examples thereof include propyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, vinyltrimethoxysilane, and γ-chloropropyltrimethoxysilane.
[0071]
Examples of the filler include calcium carbonate, barium sulfate, kaolin, talc, carbon black, alumina, magnesium oxide, and inorganic / organic balloons.
[0072]
Examples of the thixotropic agent include surface-treated calcium carbonate, finely divided silica, bentonite, and sepiolite. In particular, the addition of a thixotropic agent is preferred from the viewpoint of stabilizing the foam after foaming.
[0073]
The sheet structure of the present invention is obtained by laminating a moisture-cured foam after mixing and stirring the above-mentioned solventless moisture-curable hot-melt urethane resin composition while heating and melting the mixture, foaming with water, and the like. It is characterized by.
[0074]
The sheet structure of the present invention is a foamed layer obtained by mixing and stirring an inert gas in advance and foaming with water in a state where the solvent-free moisture-curable hot melt urethane resin composition is heated and melted, and then foamed with water. May be laminated.
[0075]
The sheet structure of the present invention is obtained by mixing and stirring the above-mentioned solventless moisture-curable hot-melt urethane resin composition in a molten state while heating and foaming with water, and then laminating the moisture-cured foam, and further leather Characterized by laminating various film layers.
[0076]
The sheet structure of the present invention is a foamed layer obtained by mixing and stirring an inert gas in advance and foaming with water in a state where the solvent-free moisture-curable hot melt urethane resin composition is heated and melted, and then foamed with water. And a leather-like film layer may be further laminated.
[0077]
The sheet structure of the present invention has a leather-like film and, on the film, the solventless moisture-curable hot melt urethane resin composition, after foaming with water, and then having a cured foam layer. Is also good.
[0078]
The sheet structure of the present invention is obtained by mixing a leather-like film and the solvent-free moisture-curable hot melt urethane resin composition on the film with an inert gas in advance, foaming with water, and then curing. It may have a foamed layer.
[0079]
The degree of foaming of the foam of the present invention can be appropriately adjusted depending on its use, and is not particularly limited as long as the texture or the strength is not impaired. For example, in the case of artificial leather use or synthetic leather use, the foaming degree is usually preferably in the range of 1.5 to 3.0 times. Here, the “expansion degree” refers to the volume (V) of the resin before foaming.₁) And the volume of the foamed resin (V₂) Ratio [V₂/ V₁] Is represented.
[0080]
A sheet structure can be obtained from the solventless moisture-curable hot melt urethane resin composition of the present invention and a sheet substrate. That is, a sheet structure can be obtained by applying the resin composition on a sheet substrate in a heated and molten state, foaming with water, and then curing with moisture to form a foamed layer. Needless to say, a sheet structure in which a sheet substrate is further laminated on the foam layer, or a sheet structure in which a foam layer made of the above resin composition is integrated between three or more sheet substrates, can also be used.
[0081]
Examples of the sheet base constituting the sheet structure of the present invention include, for example, nonwoven fabrics, woven fabrics, base fabrics and natural leathers generally used for artificial leather and synthetic leather such as knitted fabrics, various plastic sheets, and films. There is no particular limitation as long as it is a film with release paper, release paper, paper or the like. In addition, nonwoven fabrics, woven fabrics, knitted fabrics and the like in which the base fabric is impregnated with at least one or more of a solvent-based and water-based polyurethane resin, an acrylic resin, a rubber-based (SBR, NBR, etc.) latex, etc. There is no particular limitation as long as it is a base cloth or natural leather used for artificial leather or synthetic leather.
[0082]
The film as the sheet substrate and the film with release paper used in the present invention are preferably polyurethane resins conventionally used for artificial leather or synthetic leather, and are usually solvent-based resins, water-based resins, hot-melt resins and the like. It can be obtained by coating and drying on top.
[0083]
The foam and the sheet structure in the present invention were heated and melted with the solvent-free moisture-curable hot-melt urethane resin composition of the present invention, and were mixed with an inert gas as necessary, and foamed with water. The foamed resin is uniformly laminated and cooled and solidified, for example, between the release paper, or between the sheet base material and the release paper, or between the base fabric and the leather-like film, or between the release paper and the water-repellent cloth and film. The method is not particularly limited as long as the method can be crosslinked and processed. Further, after adjusting such a foam, it may be bonded to a sheet substrate or / and a leather-like film using a solvent-based adhesive, a water-based adhesive, a hot melt adhesive, or the like. In order to promote foaming and curing of the foam, humidification is applied to the surface of the substrate or the surface of the foam to which the foam is bonded, or the surface of the substrate or the surface of the foam to which the foam is integrated. Processing may be performed.
[0084]
The equipment for foaming the solventless moisture-curable hot-melt urethane resin composition of the present invention is preferably an equipment capable of uniformly mixing while mixing a predetermined amount of an inert gas, if necessary. The mixture can be heated and kept warm to avoid poor coating and poor adhesion without flowing when the foaming layer is not formed due to cooling and thickening due to agitation or when processed as a foam layer on a substrate or film. A structure is desirable.
[0085]
When producing the foam and the sheet structure of the present invention, the solvent-free moisture-curable hot-melt urethane resin composition of the present invention is heated and melted and foamed with water. The temperature is equal to or higher than the temperature at which the polymer (A) melts, and is preferably in the range of 60 to 200 ° C. When the heating temperature is in such a range, the control of foaming of the resin composition is easy and a uniform foam is easily obtained, which is preferable.
[0086]
As an apparatus for producing a foam or a sheet structure in the present invention, for example, industrially, a tank for heating and melting the prepolymer (A), a tank for storing and supplying water and other additives, and each tank are used. A tank for mixing the respective materials, a belt for continuously transporting release paper and a sheet substrate, a nozzle for supplying a molten resin composition onto the belt, a humidifying chamber for curing the foam, and a heating chamber as necessary , And another sheet base supply unit. The above-described device is representative, and various other modifications may be used.
[0087]
The equipment for foaming the resin composition of the present invention by using an inert gas in combination is not particularly limited as long as the equipment is capable of uniformly mixing a predetermined amount of the inert gas. In order to avoid the occurrence of poor coating and poor adhesion without flowing when the foaming is not uniform due to cooling and thickening due to stirring at the time of mixing or when processed as a foam on a substrate, film or sheet. A structure that can heat and maintain the mixture is desirable.
[0088]
There are no particular restrictions on various processing methods, such as surface processing on the foam or sheet structure obtained by the present invention by known or common lamination or coating, or buffing.
[0089]
INDUSTRIAL APPLICABILITY As described above, according to the present invention, a solvent-free moisture-curable hot-melt urethane resin composition having particularly excellent adhesiveness, foamability, and durability (in particular, hydrolysis resistance and heat resistance), and the urethane resin composition , A sheet structure using the same, and a method for producing the sheet structure.
[0090]
The solvent-free moisture-curable hot-melt urethane resin composition of the present invention, and a foam and a sheet structure using the same are, for example, shoes, furniture, clothing, vehicles such as automobiles, bags, cases, and synthetic leather. In addition to and artificial leather, adhesives, adhesives, sealing agents, paints, coatings, films, sheets, heat insulating materials, heat insulating materials, sound absorbing materials, cushion materials, non-slip, polishing pads, electronic and electrical materials, building materials, civil engineering It is extremely practical for a wide range of applications such as medical components.
[0091]
【Example】
Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to only these Examples. In the following, all parts and percentages are by weight unless otherwise specified. Various properties were measured according to the following methods.
[0092]
[Production method of skin film 1]
A solvent type urethane resin for synthetic leather, Chrisbon NY324 (manufactured by Dainippon Ink and Chemicals, Inc.), pigment DILA-6001 (manufactured by Dainippon Ink and Chemicals, Inc.), methyl ethyl ketone (MEK) and dimethylformamide (DMF) ) Was mixed and stirred, and the amount of coating was 100 g / m on release paper using a knife coater.²(Wet), dried at 70 ° C. for 1 minute, and then dried at 120 ° C. for 2 minutes to produce a 30 μm thick skin film 1.
[0093]
[Measurement method of softening point]
The softening point of each of the prepolymers obtained in the examples and comparative examples was measured at a heating rate of 5 ° C./min under a nitrogen atmosphere using a differential calorimeter (DSC, manufactured by Mac Science).
[0094]
[Adhesiveness measurement method]
A cloth hot melt tape was thermocompression-bonded at 130 ° C. for 5 seconds to the skin film 1 of the sheet structure with the skin film left for 5 days in an environment of a temperature of 23 ° C. and a relative humidity of 65%, and then at a head speed of 200 mm / min. According to JIS K6311, the peel strength was measured using Tensilon, and the adhesiveness was evaluated.
[0095]
[Method of measuring hydrolysis resistance]
After subjecting the sheet structure with the skin film to a hydrolysis resistance test (jungle test conditions: 70 ° C., 95% relative humidity, holding for 12 weeks), the peel strength was measured in the same manner as the above-described method for evaluating adhesiveness. The retention and the change in appearance after the evaluation were observed and evaluated according to the following criteria.
：: No change in appearance after jungle test.
X: Appearance change after jungle test.
[0096]
[Measurement method of heat resistance]
After subjecting the sheet structure with the skin film to a heat resistance test (test condition: holding at 120 ° C. for 500 hours), the peel strength was measured in the same manner as the above-described method for evaluating the adhesiveness, and the retention and the appearance after the evaluation were measured. Changes were observed and evaluated according to the following criteria.
：: No change in appearance after the test.
X: Appearance change after test.
[0097]
<< Example 1 >> Manufacturing method of sheet structure 1 with skin film
70 parts of polytetramethylene glycol (hereinafter abbreviated as PTMG1400) having a number average molecular weight of 1400, adipic acid (abbreviated as AA in the table), and hexanediol (abbreviated as HG in the table) in a 1 liter four-necked flask having a number average molecular weight of 1400. 30 parts of a polyester polyol having a number average molecular weight of 2000 (described as polyester polyol 2000 in the table) was heated under reduced pressure to 120 ° C. and dehydrated until the water content became 0.05%. After cooling to 40 ° C., 4,4′-diphenylmethane diisocyanate (MDI) was added so as to have an NCO content (% by weight) (hereinafter abbreviated as NCO%) shown in Table 1, and then to 90 ° C. The temperature was raised and the reaction was carried out for 3 hours until the NCO% became constant, to obtain a prepolymer 1. The viscosity at 125 ° C. of the cone plate viscometer was 7,000 mPa · s. While heating the obtained prepolymer 1 to 120 ° C. and melting it at 120 ° C., MDI was added to 100 parts of the prepolymer 1 to obtain the total NCO group content (% by weight) shown in Table 1. 1.0 part of ethylene glycol (EG), POLYCAT-8 [manufactured by Air Products Japan; N, N-dimethylcyclohexylamine (DMCHA), ratio of catalyst constant; KW₂/ KW₁= 3.73] and 0.12 part of water together with 0.12 part of water, and the mixture was mixed and foamed about 2.8 times. Immediately, it is applied to the skin film 1 with a thickness of 50 μm, bonded to a polyurethane-impregnated nonwoven fabric, cooled, and left for 5 days in an environment of a temperature of 23 ° C. and a relative humidity of 65% to form a sheet-like surface film. Structure 1 was obtained. The results of evaluating the properties of the sheet-like structure 1 with a skin film of the present invention are shown in Table 1, and were excellent in foamability, adhesion, heat resistance, and hydrolysis resistance.
[0098]
<< Example 2 >> Method for producing sheet structure 2 with surface film
The prepolymer 1 obtained in Example 1 was heated and melted at 120 ° C. in a 1-liter four-necked flask and heated at 120 ° C., and the MDI was measured as shown in Table 1 with respect to 100 parts of the prepolymer 1. 1.0 part of EG, 0.10 part of POLYCAT-8, and 0.12 part of water were added and mixed to obtain the indicated total NCO group content, and foamed about 3.0 times. This was confirmed from the volume. Immediately, it is applied on the skin film 1 at a thickness of 50 μm, bonded to a polyurethane-impregnated nonwoven fabric, cooled, and left for 5 days in an environment of a temperature of 23 ° C. and a relative humidity of 65% to form a sheet-like sheet structure with a skin film. Body 2 was obtained. The results of evaluating the properties of the sheet-like sheet structure 2 with a skin film of the present invention are shown in Table 1, and were excellent in foamability, adhesiveness, heat resistance, and hydrolysis resistance.
[0099]
<< Example 3 >> Manufacturing method of sheet structure 3 with surface film
70 parts of PTMG1400 and 30 parts of polyester polyol 2000 were heated under reduced pressure to 120 ° C. in a 1-liter four-necked flask, and dehydrated until the water content became 0.05%. After cooling to 40 ° C., 4,4′-diphenylmethane diisocyanate (MDI) was added so as to have the NCO content (% by weight) shown in Table 1, and then the temperature was raised to 90 ° C. The reaction was carried out for 3 hours until the temperature became constant to obtain prepolymer 2. The viscosity at 125 ° C. with a cone plate viscometer was 9000 mPa · s. The obtained prepolymer 2 was heated to 120 ° C., melted, and heated at 120 ° C., so that the MDI was adjusted to 100 parts of the prepolymer 2 so that the total NCO group content shown in Table 1 was obtained. , 0.16 parts of POLYCAT-8, and 0.10 parts of water were added and mixed, and it was confirmed from the volume that foaming was performed about 2.5 times. Immediately, it is coated on the skin film 1 with a thickness of 50 μm, bonded to a polyurethane-impregnated nonwoven fabric, cooled, and left for 5 days in an environment of a temperature of 23 ° C. and a relative humidity of 65% to form a sheet-like surface film. Structure 3 was obtained. The results of evaluating the properties of the sheet-like structure 3 with a skin film of the present invention are shown in Table 1, and were excellent in foaming properties, adhesive properties, heat resistance, and hydrolysis resistance.
[0100]
<< Example 4 >> Manufacturing method of sheet structure 4 with surface film
The prepolymer 1 obtained in Example 1 was heated and melted at 120 ° C., and then heated to 120 ° C. and the propylene glycol having a number average molecular weight of 1000 (hereinafter referred to as PPG1000) and the MDI were shown in Table 1. While mixing dibutylditin dilaurate (DBSNDL) at a (prepolymer 1 + MDI) /PPG1000/DBSNDL=100/3.0/0.1 weight ratio so as to have an NCO group content, 1.0 part of EG was added. It was confirmed from the volume that 0.10 part of POLYCAT-8 and 0.12 part of water were added together and mixed, and foamed about 2.8 times. A foamed prepolymer 3 was obtained. Immediately, it is applied on the skin film 1 with a thickness of 50 μm, bonded to a polyurethane-impregnated nonwoven fabric, cooled, and left for 5 days in an environment of a temperature of 23 ° C. and a relative humidity of 65% to form a sheet-like skin film. Sheet structure 4 was obtained. Table 1 shows the results of evaluating the properties of the sheet-like sheet structure with a surface film 4 of the present invention, which were excellent in foamed blue, adhesiveness, heat resistance, and hydrolysis resistance.
[0101]
<< Comparative Example 1 >>
While heating the prepolymer 1 obtained in Example 1 at 120 ° C. and melting at 120 ° C. in a 1-liter four-necked flask, EG was added to 100 parts of the prepolymer 1.30 with EG. Parts, 0.10 part of POLYCAT-8 and 0.15 part of water were added and mixed, and it was confirmed from the volume that foaming was about 1.0 times. Immediately, it is coated on the skin film 1 at a thickness of 50 μm, bonded to a polyurethane-impregnated nonwoven fabric, cooled, and left for 5 days in an environment of a temperature of 23 ° C. and a relative humidity of 65% to obtain a sheet-like sheet with a surface film. Structure 5 was obtained. Table 2 shows the characteristic evaluation results. This product was inferior in foaming property and heat resistance.
[0102]
<< Comparative Example 2 >>
While heating the prepolymer 2 obtained in Example 3 at 120 ° C. and melting at 120 ° C. in a 1-liter four-necked flask, only 100 parts of the prepolymer 2 were mixed. It was confirmed from the volume that foaming was almost zero, that is, 0 times. Immediately, it is coated on the skin film 1 at a thickness of 50 μm, bonded to a polyurethane-impregnated nonwoven fabric, cooled, and left for 5 days in an environment of a temperature of 23 ° C. and a relative humidity of 65% to obtain a sheet-like sheet with a surface film. Structure 6 was obtained. The characteristics evaluation results are shown in Table 2. This product was inferior in foaming property and heat resistance.
[0103]
[Table 1]

[0104]
[Table 2]

[0105]
【The invention's effect】
The solvent-free moisture-curable hot-melt urethane resin composition of the present invention comprises a hot-melt urethane prepolymer containing an isocyanate group (A), a polyisocyanate component (B), a compound (C) having at least two active hydrogens, and water. It is a resin composition comprising (D), and is excellent in foamability, adhesiveness and durability (in particular, heat resistance and hydrolysis resistance). The resin composition of the present invention is heated and melted, mixed and stirred, foamed with water, and then moisture-cured to obtain a foam, and a sheet structure using the foam is, for example, shoes or furniture. , Clothing, vehicles such as automobiles, bags, cases, etc., besides synthetic leather and artificial leather, adhesives, adhesives, sealing agents, paints, coatings, films, sheets, heat insulating materials, heat insulating materials, sound absorbing materials, It is extremely practical in a wide range of applications such as cushioning materials, non-slip, polishing pads, electronic and electronic materials, building materials, civil engineering, medical materials, and the like.

Claims (15)

A prepolymer (A) and a polyisocyanate component, which are composed of an isocyanate group-containing hot melt urethane prepolymer (A), a polyisocyanate component (B), a compound (C) having at least two active hydrogens, and water (D) as essential components. A solvent-free moisture-curable hot-melt urethane resin composition having a total isocyanate (NCO) group content of 2.0 to 10.0% by weight based on the total weight of (B). The solvent-free moisture-curable hot melt urethane resin composition according to claim 1, wherein the softening point of the prepolymer (A) is in the range of 30 to 160C. The solvent-free moisture-curable hot-melt urethane resin composition according to claim 1 or 2, wherein the prepolymer (A) is an isocyanate group-terminated urethane prepolymer obtained by reacting a polyol component and a polyisocyanate component. The solvent-free moisture-curable hot water according to claim 1 or 2, wherein the total NCO group content based on the total weight of the prepolymer (A) and the polyisocyanate component (B) is in the range of 2.5 to 8.0% by weight. Melt urethane resin composition. The total charged weight after the total NCO groups of the prepolymer (A) and the polyisocyanate component (B) are reacted with the compound (C) having at least two active hydrogens and water (D) “(A) + (B) The solvent-free moisture-curable hot-melt urethane resin composition according to claim 1 or 2, wherein the residual NCO group content with respect to "+ (C) + (D)" is in the range of 1.5 to 9.0% by weight. 3. The solvent-free moisture-curable hot melt urethane resin composition according to claim 1, wherein the prepolymer (A) has an isocyanate group-terminated urethane prepolymer or a urethane prepolymer having a hydrolyzable alkoxysilyl group and an isocyanate group. object. The ratio of the reactive group equivalent of the compound (C) having at least two active hydrogens and water (D) [reactive group equivalent (c) / reactive group equivalent (d)] is in the range of 0.5 to 10.0. The solvent-free moisture-curable hot-melt urethane resin composition according to claim 1 or 2. The solvent-free moisture-curable hot melt urethane resin composition according to claim 1 or 2, further comprising an amine catalyst (E) as an essential component. The amine-based catalyst (E) has a catalyst constant ratio of KW ₂ / KW ₁ [where KW ₂ is the catalyst constant per weight of the reaction between water and tolylene diisocyanate, and KW ₁ is diethylene glycol and Represents the catalytic constant per weight of the reaction with tolylene diisocyanate. ] Is 0.5 or more, The solvent-free moisture-curable hot-melt urethane resin composition of Claim 8. The solvent-free moisture-curable hot-melt urethane resin composition according to claim 1 or 2, further comprising a foam stabilizer (F) as an essential component. The solventless moisture-curable hot melt urethane resin composition according to claim 10, wherein the foam stabilizer (F) contains a polysiloxane-polyoxyalkylene copolymer. The solvent-free moisture-curable hot-melt urethane resin composition according to any one of claims 1 to 11 is heated and melted, mixed and stirred, foamed with water, and cured by moisture. Foam. A sheet structure comprising the foam according to claim 12 laminated on a sheet substrate. A sheet structure, comprising: laminating the foam according to claim 12 on a sheet substrate; and further laminating a leather-like film layer. On a sheet substrate, the solvent-free moisture-curable hot melt urethane resin composition according to any one of claims 1 to 11 is heated and melted, foamed and laminated with water, and then moisture-cured. Of manufacturing a sheet structure.