JP4245977B2 - Acrylic copolymer aqueous composition for forming foamed layer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an aqueous acrylic copolymer composition for producing a foamed layer, which can be crosslinked under relatively mild conditions and form a strong foamed layer containing practically no harmful substance on a fiber base. <P>SOLUTION: This aqueous acrylic copolymer composition for forming a foamed layer comprises micro particles (A) of an acrylic copolymer with a specific glass transition point (Tg) and containing carbonyl and carboxyl groups, a hydrazine derivative (B) having a plurality of hydrazide residues in the molecule, a foaming agent (C) and a foam stabilizer (D). <P>COPYRIGHT: (C)2005,JPO&amp;NCIPI

Description

〔式中、R⁴は炭素数10〜20のアルキル基を表し、M⁺は一般式(3)で定義したとおりである〕
【００５６】
で示されるアルキルアリールスルホン酸塩型アニオン系界面活性剤を例示することができ、具体的にはドデシルベンゼンスルホン酸ナトリウム等を例示することができる。
【００５７】
本発明において用いることのできるアニオン系界面活性剤としては、さらに、下記一般式(5)、
【００５８】
【化２】

〔式中、R⁵は１つ以上の芳香環を含む炭化水素基、EOは一般式(2)で、M⁺は一般式(3)で定義したとおりである〕
【００５９】
上記一般式(5)におけるR⁵は、下記３種の構造式で示されるジスチリルの何れか又はそれらの混合物から誘導されたものであることが好ましい。
【００６０】
【化３】

【００６１】
前記のアニオン系界面活性剤におけるポリオキシエチレン鎖の長さ（ｐの値）としては、一般に４〜50の範囲であり、好ましく５〜45の範囲であるのがよい。
【００６２】
前記一般式(5)で示されるアニオン系界面活性剤の具体例としては、例えば、ハイテノールNF-13、ハイテノールNF-17〔商品名；以上第一工業製薬(株)製〕、ニューコール707SF、ニューコール710SF、ニューコール714SF、ニューコール723SF、ニューコール740SF〔商品名；以上日本乳化剤(株)製〕等を挙げることができる。
【００６３】
また、これら乳化剤のアルキル基の水素の一部をフッ素で置換されたものも使用可能である。
【００６４】
本発明で用いることのできるアニオン系界面活性剤としては、さらに、例えば、オレイン酸ナトリウム、ステアリン酸ナトリウム等の高級脂肪酸塩；例えば、モノオクチルスルホコハク酸ナトリウム、ジオクチルスルホコハク酸ナトリウム、ポリオキシエチレンラウリルスルホコハク酸ナトリウム等のアルキルスルホコハク酸エステル塩及びその誘導体；等を例示することができる。
【００６５】
さらにアニオン系反応性乳化剤として、例えば、「エレミノールJS-2」、「エレミノールRS-30」〔以上、三洋化成工業(株)製〕、「アクアロンHS-10N」、「アクアロンHS-20N」〔以上、第一工業製薬(株)製〕、「アデカリアソープSE-10N」〔旭電化工業(株)製〕、「ラテムルS-120」、「ラテムルS-120A」、「ラテムルS-180」、「ラテムルS-180A」〔以上、花王(株)製〕も使用可能である。
【００６６】
これらアニオン系界面活性剤は、それぞれ単独で又は２種以上組み合わせて使用することができ、その使用量は、得られるアクリル系共重合体の微粒子(A) 100重量部に対して、すなわち前記単量体(a)〜(e)の合計100重量部に対して、有効成分として５重量部以下であることが好ましく、0.1〜２重量部の範囲であることが特に好ましい。該アニオン系界面活性剤の使用量が、該上限値以下であれば、得られる水性分散液の機械的安定性、化学的安定性がよいので好ましい。また、該下限値以上用いることによって、水性乳化重合の際の凝集物の発生や乳化状態の破壊を防止し、得られる水性分散液の貯蔵安定性や機械的安定性を向上させる可能性があるので好ましい。
【００６７】
さらに、アニオン系界面活性剤の使用の割合は、使用される全界面活性剤量に対して、有効成分比率で40重量％以下であることが好ましく、５〜30重量％の範囲内であることがより好ましい。該使用割合が該上限値以下であれば、得られる水性分散液の化学的安定性が優れているので好ましい。また該下限値以上用いることにより、乳化重合の際の凝集物の発生や乳化状態の破壊、得られる水性分散液の貯蔵安定性や機械的安定性を向上させることができるので好ましい。
【００６８】
さらにまた、本発明におけるアクリル系共重合体の乳化共重合に際しての全界面活性剤の使用量は、アクリル系共重合体の微粒子(A)100重量部に対して、すなわち前記単量体(a)〜(e)の合計100重量部に対して、有効成分として１〜10重量部の範囲であることが好ましく、1.5〜８重量部の範囲であることがより好ましく、2.5〜７重量部の範囲であることが特に好ましい。該使用割合が該上限値以下であれば、乳化重合安定性が優れており、得られる水性分散液の機械的安定性、化学的安定性が優れていると共に、水性分散液に基づく組成物被膜の基材への密着性を阻害することがないので好ましい。また該下限値以上用いることにより、乳化重合の際の凝集物の発生や乳化状態の破壊、得られる水性分散液の貯蔵安定性や機械的安定性を向上させることができるので好ましい。
【００６９】
さらにまた、最近、アクリル系共重合体の水性分散液中に汎用されているアルキルフェニル基を含む界面活性剤が、排水中に含まれて河川等に排出されたとき、それら界面活性剤の加水分解によって生じるアルキルフェノールが、それら河川及びそれが流入する海の中に生息する生物、特に魚貝類に取り込まれて、それら生物の内分泌機能（エンドクリン）破壊物質（所謂、環境ホルモン）として作用することが知られるようになった。このようなアルキルフェノールは、これら魚介類の摂取を通して、又は直接それら河川等の水を使用する上水道の水を通して、人の体内に入る危険性が高いことが指摘されている。
【００７０】
本発明においては、前記のノニオン系及びアニオン系界面活性剤の中から、上記のようなアルキルフェニル基を含まないものを選んで用いることにより上記の問題点を解消したアクリル系共重合体の水性分散液を得ることもできる。
【００７１】
このような界面活性剤としては、ノニオン系界面活性剤類として、前記一般式(2)で示される炭素数10〜20の脂肪族アルコールポリオキシエチレンエーテル類、ソルビタン高級脂肪酸エステル類、ポリオキシエチレンソルビタン高級脂肪酸エステル類、ポリオキシエチレン高級脂肪酸エステル類、グリセリン高級脂肪酸エステル類、ポリオキシエチレン・ポリオキシプロピレン・ブロックコポリマー、ポリオキシエチレンアルキル（又はアルケニル）エーテルジアルキル正リン酸エステル類などを使用することができる。またアニオン系界面活性剤類としては、前記一般式(3)で示されるポリオキシエチレンアルキル又はアルケニルエーテル硫酸エステル塩類、前記一般式(4)で示されるアルキルアリールスルホン酸塩類、アルキル（もしくはアルケニル）硫酸エステル塩類、ポリオキシエチレンアルキル（もしくはアルケニル）エーテル硫酸エステル塩類、アルキル（もしくはアルケニル）スルホコハク酸エステル塩及びその誘導体類、アルキル（又はアルケニル）リン酸エステル塩類、ポリオキシエチレンアルキルエーテルリン酸エステル塩類、前記一般式(5)のポリオキシエチレン多環フェニルエーテル型界面活性剤などを使用することができる。
【００７２】
これらの界面活性剤を重合用乳化剤として用いる場合には、これらを適宜組み合わせて、前記の使用量範囲で使用するのがよい。
【００７３】
本発明における水性アクリル系共重合体微粒子(A)の乳化共重合に際しては、前記のノニオン系及びアニオン系界面活性剤と共に、必要に応じ、且つ本発明の優れた効果を損なわない範囲において、保護コロイドを併用することができる。
【００７４】
このような保護コロイドとしては、例えば、部分ケン化ポリビニルアルコール、完全ケン化ポリビニルアルコール、変性ポリビニルアルコール等のポリビニルアルコール類；例えば、ヒドロキシエチルセルロース、ヒドロキシプロピルセルロース、カルボキシメチルセルロース塩等のセルロース誘導体；及びグアーガムなどの天然多糖類；などが挙げられる。これら保護コロイドの使用量は、例えば、アクリル系共重合体の微粒子(A) 100重量部に対して０〜３重量部程度の量を例示できる。
【００７５】
本発明におけるアクリル系共重合体の乳化重合に際しては、重合開始剤として、例えば、過硫酸アンモニウム、過硫酸カリウム、過硫酸ナトリウムなどの過硫酸塩類；t-ブチルハイドロペルオキシド、クメンハイドロペルオキシド、p-メンタンハイドロペルオキシドなどの有機過酸化物類；過酸化水素；などを、一種もしくは複数種併用して使用することができる。重合開始剤の使用量は適当に選択できるが、例えば、アクリル系共重合体の微粒子(A)100重量部に対して約0.05〜１重量部、より好ましくは約0.1〜0.7重量部、特に好ましくは約0.1〜0.5重量部の如き使用量を例示することができる。
【００７６】
また乳化重合に際して、所望により、還元剤を併用することができる。該還元剤としては、例えば、アスコルビン酸、酒石酸、クエン酸、ブドウ糖等の還元性有機化合物；例えば、チオ硫酸ナトリウム、亜硫酸ナトリウム、重亜硫酸ナトリウム、メタ重亜硫酸ナトリウム等の還元性無機化合物を例示できる。還元剤の使用量は適宜選択できるが、例えば、アクリル系共重合体の微粒子(A)100重量部に対して約0.05〜１重量部の如き使用量を例示することができる。
【００７７】
さらにまた、乳化重合に際して、所望により連鎖移動剤を用いることもできる。このような連鎖移動剤としては、例えば、シアノ酢酸；シアノ酢酸の炭素数１〜８アルキルエステル類；ブロモ酢酸；ブロモ酢酸の炭素数１〜８アルキルエステル類；例えば、アントラセン、フェナントレン、フルオレン、9-フェニルフルオレンなどの芳香族化合物類；例えば、p-ニトロアニリン、ニトロベンゼン、ジニトロベンゼン、p-ニトロ安息香酸、p-ニトロフェノール、p-ニトロトルエン等の芳香族ニトロ化合物類；例えば、ベンゾキノン、 2,3,5,6-テトラメチル-p-ベンゾキノン等のベンゾキノン誘導体類；トリブチルボラン等のボラン誘導体；例えば、四臭化炭素、四塩化炭素、 1,1,2,2-テトラブロモエタン、トリブロモエチレン、トリクロロエチレン、ブロモトリクロロメタン、トリブロモメタン、3-クロロ-1-プロペン等のハロゲン化炭化水素類；例えば、クロラール、フラルデヒド等のアルデヒド類；炭素数１〜18のアルキルメルカプタン類；例えば、チオフェノール、トルエンメルカプタン等の芳香族メルカプタン類；メルカプト酢酸；メルカプト酢酸の炭素数１〜10アルキルエステル類；炭素数１〜12のヒドロキルアルキルメルカプタン類；例えば、ビネン、テルピノレン等のテルペン類；等を挙げることができる。
【００７８】
上記連鎖移動剤を用いる場合その使用量は、アクリル系共重合体の微粒子(A) 100重量部に対して約0.005〜３重量部であるのが好ましい。
【００７９】
乳化共重合の好適な実施態様としては、前記の界面活性剤及び／又は保護コロイドを含有し、或いはこれらを含有しない水性媒体中に、前記単量体(a)〜(e)、界面活性剤及び／又は保護コロイド、重合開始剤、並びに、必要に応じて使用する還元剤を逐次添加する態様を例示することができる。共重合温度は、約40〜100℃、好ましくは約50〜90℃程度であるのがよい。
【００８０】
かくして得られたアクリル系共重合体微粒子(A)の水性分散液は、必要に応じて、アンモニア水等によってpＨ調節することができる。このような分散液は、通常、固形分濃度30〜65重量％、粘度10〜3000 mPa・s（BH型回転粘度計、25℃、20rpm；粘度測定条件以下同様）、pＨ２〜９程度であるが、アクリル系共重合体の乳化共重合の安定性、得られる共重合体水性分散液の機械的安定性、貯蔵安定性、本発明の組成物作製に際しての種々の添加剤の配合適性の優秀さなどの理由から、固形分濃度50〜65重量％であることが好ましい。また水性媒体中のアクリル系共重合体微粒子の平均粒子径は、好ましくは200〜500 nm、より好ましくは230〜350 nmであるのがよい。平均粒子径が該下限値以上であれば、比較的低粘度で固形分の高い共重合体水性分散液が得られやすく、各種添加剤との混和性も優れたものとなるので好ましく、また該上限値以下であれば、乳化重合に際して反応性を阻害することがなく、得られるエマルションの貯蔵安定性も良好なので好ましい。
【００８１】
なお本明細書において、共重合体分散粒子の平均粒子径は、日本化学会編「新実験化学講座４ 基礎技術３ 光（II）」第725〜741頁（昭和51年７月20日丸善株式会社発行）に記載された動的光散乱法（以下、DLS法ということがある）により測定された値であり、具体的には以下に述べる方法で測定された値である。
【００８２】
平均粒子径：
共重合体水性分散液を蒸留水で５万〜15万倍に希釈し、十分に攪拌混合した後、21mmφガラスセル中にパスツールピペットを用いて約10ml採取し、これを動的光散乱光度計「DLS-700」〔大塚電子(株)製〕の所定の位置にセットして、以下の測定条件下で測定し、測定結果をコンピュータ処理して平均粒子径を求める。
【００８３】
〔測定条件〕
測定温度 24〜26℃
クロックレート(Clock Rate) 10μsec
コレレ-ションチャンネル(Corelation Channel) 512
積算測定回数 200個
光散乱角 90°
【００８４】
〔発泡層形成用アクリル系共重合体水性組成物〕
本発明の発泡層形成用アクリル系共重合体水性組成物は、以上述べたアクリル系共重合体微粒子(A)の水性分散液と共に、分子内に複数のヒドラジド残基を有するヒドラジン誘導体(B)を含有してなるものである。このことにより本発明の共重合体水性組成物は、前記の如く比較的穏やかな加工条件下で加工することができ、ホルムアルデヒドなどの有害物質の発生がなく、得られる発泡層の繊維基材への密着性、吸音性、柔軟性、反撥弾性、摩擦堅牢度、耐水性などの特性を向上させることができる。
【００８５】
本発明に用いることのできるヒドラジン誘導体(B)は、必ずしも限定されるものではないが、水100重量部に対して１重量部以上溶解するものが好ましく、また炭素数２〜10を含有する有機化合物であることが好ましい。このようなヒドラジン誘導体(B)としては、例えば、蓚酸ジヒドラジド、マロン酸ジヒドラジド、コハク酸ジヒドラジド、グルタル酸ジヒドラジド、アジピン酸ジヒドラジド、セバシン酸ジヒドラジド、マレイン酸ジヒドラジド、フマル酸ジヒドラジド、イタコン酸ジヒドラジド等の炭素数２〜10を含有するジカルボン酸のジヒドラジド；例えば、エチレン-1,2-ジヒドラジン、プロピレン-1,3-ジヒドラジン、ブチレン-1,4-ジヒドラジン等の水溶性の炭素数２〜４を含有する有機ジヒドラジンを挙げることができる。これらのうち、炭素数２〜10を含有するジカルボン酸のジヒドラジド、中でもアジピン酸ジヒドラジド、イソフタル酸ジヒドラジド、コハク酸ヒドラジドの使用が特に好ましい。
【００８６】
これらヒドラジン誘導体(B)は、前記アクリル系共重合体の微粒子(A)中のカルボニル基１当量に対して、好ましくは0.25〜２当量、より好ましくは0.3〜1.5当量、さらに好ましくは0.4〜1.2当量の範囲であることが望ましい。カルボジヒドラジドの使用量が該下限値以上であれば、アクリル系共重合体の架橋が十分に行われ、得られる発泡層の摩擦堅牢度、反撥弾性、吸音性などが優れたものとなるので好ましく、また該上限値以下であれば発泡層の繊維基材への密着性が損なわれることがないので好ましい。
【００８７】
かくして本発明に用いられるアクリル系共重合体は、実質的に乾燥させるだけで、ヒドラジン誘導体(B)のヒドラジン残基が該共重合体のカルボニル基と架橋反応して強固な架橋被膜を与えることができ、布、紙、繊維等の繊維基材に対し強い密着性を有する被膜を与えると共に、吸音性、柔軟性、反撥弾性、摩擦堅牢度、耐水性などを向上させる。
【００８８】
一般に、共重合体の架橋度合はその共重合体から形成されるフィルムの動的粘弾性特性を測定することにより知ることができる。
【００８９】
図１は、共重合体から形成されるフィルムの動的粘弾性特性を表す概念図である。縦軸に弾性率（例えばN/m²）、横軸に温度（℃）をとるとき、一般に樹脂は、極低温域ではガラス状態を呈するガラス状領域で高い弾性率を維持しているが、温度上昇につれて次第に長鎖分子が全体としてゆっくりと動き始め、ある温度を超えると急激にその弾性率が低下する。この時の温度がその共重合体のガラス転移点（Tg）であり、温度上昇に伴って弾性率が急激に低下するこの領域が転移域である。さらに温度が上昇すると再び弾性率の低下率が小さい段丘状の領域、すなわちゴム状領域に至る。この領域では、樹脂の分子鎖の絡み合い（物理的）及び分子の架橋度合（化学的）によって弾性率が維持されるものといわれている。このゴム状領域が高温側にまで及んでいる共重合体は高温弾性率が高いことになる。さらに温度を上昇させると、共重合体は急激にその弾性率を低下させて流動域に至る。この領域では、共重合体の分子鎖は自由熱運動（ブラウン運動）を行うことになる。
【００９０】
なお本明細書においては、ガラス状領域、転移域、ゴム状領域及び流動域における温度−弾性率曲線の接線の交点をそれぞれｕ、ｖ及びｗとし、それら交点のそれぞれに対応する温度をTu、Tv及びTwとするとき、温度Tuはガラス転移点Tgと一致するものとし、この温度より低温の領域をガラス状領域、温度TuとTvとの間を転移域、温度TvとTwとの間をゴム状領域、温度Twは軟化点Tmと一致するものとし、この温度より高温の領域を流動域と定義する。
【００９１】
図２は、本発明におけるアクリル系共重合体の微粒子(A)中のカルボニル基とヒドラジン誘導体(B)との配合物により形成される架橋フィルム(x)と、従来のアクリル系共重合体の非架橋又は低架橋フィルム(y)の動的粘弾性特性を比較する概念図である。図２において、本発明に係る架橋フィルムの動的粘弾性特性を表す曲線(x)は、そのゴム状領域の上限が高温領域、例えば160℃以上の温度域にまで及んでいる。それに対して従来の非架橋又は低架橋フィルムの動的粘弾性特性を表す曲線(y)は、そのゴム状領域の上限がより低い温度、例えば140℃以下の温度域までしか及んでおらず、それ以上の温度では流動域に移行してしまう。このことは、本発明のアクリル系共重合体水性組成物が高温においても優れた弾性を有することを示している。
【００９２】
なお、本明細書において、フィルムの動的粘弾性特性は下記により測定された値である。
【００９３】
動的粘弾性特性の測定：
フィルムの動的粘弾性特性は、完全自動低駆動粘弾性測定器〔レオバイブロン DDV-III-EP；東洋ボールドウィン(株)製〕を用いて測定した。測定方法は、該測定器の取扱説明書V-1180に記載されている方法に従った。以下その方法を概説する。
【００９４】
シリコーン製型枠に、乾燥皮膜の厚みが１〜２mmになる量のエマルションを流し込み、室温で３日間乾燥後さらに40℃の乾燥器中で８時間乾燥して、得られる乾燥皮膜を試料とした。測定は以下の条件下で行った。
試料寸法：引張試験用 10×50mm 厚さ１〜２mm
剪断試験用 10×20mm 厚さ３〜５mm；但し剪断試験用の試片は得られた乾燥皮膜を３枚重ねて作成した。
【００９５】
測定温度範囲：引張試験 −80℃〜約10℃
剪断試験 約10℃〜200℃
昇温速度：３℃/分
測定周波数：11 Hz
【００９６】
本発明の発泡層形成用アクリル系共重合体水性組成物は、前記のアクリル系共重合体の微粒子(A)及びヒドラジン誘導体(B)と共に、起泡剤(C)及び気泡安定剤(D)を含有してなるものである。
【００９７】
上記の起泡剤(C)は、特に限定されるものではなく、機械攪拌等により空気巻き込んで気泡を形成することを助けるものであれば何れも使用できるが、前記の界面活性剤の中から、適宜選択して使用するのが通例である。これら界面活性剤のうち、前記のごとく「環境ホルモン」を発生させない観点から、アルキルフェニル基を含まない前記のノニオン系界面活性剤類及びアニオン系界面活性剤類を用いることが好ましく、前記一般式(3)で示されるポリオキシエチレンアルキル又はアルケニルエーテル硫酸エステル塩類、前記一般式(4)で示されるアルキルアリールスルホン酸塩類、アルキル（もしくはアルケニル）硫酸エステル塩類及びポリオキシエチレンアルキル（もしくはアルケニル）エーテル硫酸エステル塩類を用いることがより好ましく、炭素数８〜20のアルキル（もしくはアルケニル）硫酸エステル塩であることがさらに好ましく、ラウリル硫酸ナトリウムであることが特に好ましい。
【００９８】
起泡剤(C)の使用量も、特に限定されるものではなく、本発明の組成物の用途、形成される発泡層の厚さ及びアクリル系共重合体微粒子(A)の水性分散液の特性値（例えば、粘度、固形分など）によって適宜の量使用することができるが、例えば該微粒子(A)100重量部に対して0.5〜５重量部用いることが好ましく、１〜３重量部用いることがさらに好ましい。
【００９９】
本発明に用いることのできる前記気泡安定剤(D)も、特に限定されるものではなく、形成された気泡安定に保つために有効なものであれば何れも使用でき、例えば寒天、カラギーナン、ペクチン、アラビアガム、ローカストビーンガム、グァガム、コーンスターチ、ゼラチン、カゼインなどの天然糊料；例えばアルギン酸ナトリウム、カルボキシメチルセルロース、メチルセルロース、ヒドロキシエチルセルロースなどの合成糊料；高級脂肪酸の塩などを例示することができるが、これらのうち、高級脂肪酸の塩、例えば炭素数12〜20の脂肪酸のアンモニウム塩の使用が好ましく、主としてステアリン酸からなる脂肪酸のアンモニウム塩の使用が特に好ましい。
【０１００】
気泡安定剤(D)の使用量も、特に限定されるものではなく、本発明の組成物の用途及び形成される発泡層の厚さ、並びに、アクリル系共重合体微粒子(A)の水性分散液の特性値（例えば、粘度、固形分など）、起泡剤(C)の種類及び使用量などによって適宜の量使用することができるが、例えば該微粒子(A)100重量部に対して１〜10重量部用いることが好ましく、２〜７重量部用いることがさらに好ましい。
【０１０１】
本発明の発泡層形成用アクリル系共重合体水性組成物には、必要に応じて、無機質充填剤を含有させることができる。このような無機質充填剤としては、実質的に水に不溶性ないし難溶性の無機質個体粉末、例えば、炭酸カルシウム、シリカ、アルミナ、カオリン、クレー、タルク、珪藻土、マイカ、水酸化アルミニウム、ガラス粉、硫酸バリウム、炭酸マグネシウム等を例示することができる。
【０１０２】
これらの無機質充填剤の配合量は、その種類や本発明の組成物により発泡層が設けられる加工製品の用途に応じて広い範囲で変化させることができるが、得られる発泡層中に占める無機化合物（無機質充填剤及び下記無機着色顔料等の合計）の量が、該発泡層の重量に基づいて50重量％以下、さらには30重量％以下であることが好ましく、特に該発泡層が吸音性を求められる自動車室内のオプションマット中に設けられるものであるときには、無機質充填剤の配合量は20重量％以下であることが好ましい。
【０１０３】
本発明の発泡層形成用アクリル系共重合体水性組成物には、必要に応じて、さらに各種の添加剤を配合することができる。
【０１０４】
これらの添加剤としては、例えば、酸化チタン、カーボンブラック、弁柄、ハンザイエロー、ベンジジンイエロー、フタロシアニンブルー、キナクリドンレッド等の有機もしくは無機の着色顔料；例えばヘキサメタリン酸ナトリウム、トリポリリン酸ナトリウム等の無機質分散剤、例えばノプコスパース 44C（商品名）〔ポリカルボン酸系、サンノプコ(株)製〕等の有機質分散剤などの分散剤；例えば、ポリビニルアルコール、セルロース系誘導体、ポリカルボン酸系樹脂、界面活性剤系等の増粘剤及び粘性改良剤；例えば、シリコーン系などの消泡剤；例えば、ターペンエチレングリコール、ブチルセロソルブ、ブチルカルビトール、ブチルカルビトールアセテート等の有機溶剤；老化防止剤；防腐剤・防黴剤；紫外線吸収剤；帯電防止剤；等を挙げることができる。
【０１０５】
本発明の発泡層形成用アクリル系共重合体水性組成物は、特に限定されるものではないが、固形分、一般に約40〜80重量％、好ましくは約45〜75重量％、特に好ましくは約50〜70重量％の範囲；pＨ、一般に７〜11、好ましくは８〜10の範囲；粘度、一般に約3,000〜100,000mPa・s、好ましくは約5,000〜50,000mPa・sの範囲（B型回転粘度計、25℃、20rpmによる、以下同様）を有することができる。
【０１０６】
また本発明組成物の使用に際しては、以上述べた特定のアクリル系共重合体の微粒子(A)、ヒドラジン誘導体(B)、起泡剤(C)及び気泡安定剤(D)、さらに必要に応じて、前記の各種添加剤を配合し、均一に混合した後、適宜の機械撹拌装置、例えば櫂型、タービン型、プロペラ型などの攪拌翼を有する攪拌機を用い、必要に応じて、窒素又は空気を吹き込みながら攪拌することにより、該組成物を発泡させる。発泡の度合（発泡倍率）は、特に限定されるものではなく、発泡層が設けられる加工製品の用途に応じて広い範囲で変化させることができるが、発泡前の組成物の容量に基づいて、一般に1.5〜６倍、好ましくは２〜５倍程度であるが、特に該発泡層が吸音性を求められる自動車室内のオプションマット中に設けられるものであるときには、２〜４倍の範囲とすることが好ましい。
【０１０７】
この発泡した組成物は、次いで、適宜の塗工手段、例えばナイフコーター、ロールコーターなどにより、繊維基材の一方又は両方の表面に塗工し、例えば熱風乾燥法、熱シリンダー法、赤外線照射法などの慣用の乾燥方法により乾燥することにより、連続気泡を有する発泡層を形成することができる。得られる発泡層の密度も、該発泡層が設けられる加工製品の用途に応じて適宜選択することができ、一般に0.2〜0.7 g/cm³の範囲であるのがよい。また発泡層を吸音性が求められる自動車室内のオプションマット中に設けるときには、0.3〜0.6 g/cm³の範囲とすることが特に好ましい。
【０１０８】
なお、本明細書において、発泡層の密度は下記により測定された値である。
【０１０９】
発泡層の密度の測定：
予め重量を測定してある容積100mLのテフロン（登録商標）製シャーレ（w₀：単位g）に、厚みが約５mmになる様に発泡体組成物を充填し、80℃で３時間乾燥した後室温まで放冷して重量を測定した（w₁：単位g）。得られた発泡層の表面に、シールを目的として、約90℃で熱熔融させたワックス（融点約60℃）を刷毛を用いて塗布し、室温まで放冷して重量を測定した（w₂：単位g）。次いでこの発泡層を含むシャーレに、満杯になるまで水を充填し重量を測定した（w₃：単位g）。これらの測定値を用い、下記の計算式に従って発泡層の密度を求めた。
【０１１０】
【数１】

但し、水１gの体積を１cm³とする。またシールとして用いたワックスの厚さは10μm前後であるため、発泡体の厚さ（約５mm）に比較して無視小であると考える。
【０１１１】
適用される適当な繊維基材としては、例えば綿、麻、毛等の天然繊維；例えばレーヨン等の再生繊維；例えばアセテート繊維、プロミックス繊維などの半合成繊維；例えばポリエステル繊維、ポリアミド繊維、ビニロン繊維等の合成繊維等からなる織布、編布、不織布、フェルト、紙などを例示することができる。
【０１１２】
次に、本発明の発泡層形成用アクリル系共重合体水性組成物により発泡層が設けられた自動車室内のオプションマットについて説明する。
【０１１３】
図３は、本発明の発泡層形成用アクリル系共重合体水性組成物を用いて作製されるオプションマットの概念図である。このオプションマット(10)において、本発明の組成物により形成された発泡層(1)は、パイル(3)の植設された繊維基材(2)と裏打ち不織布(4)の間に位置し、該裏打ち不織布(4)の背面〔発泡層(1)と接している面の反対側の面〕には、滑り止め層(5)が形成されている。パイル(3)、繊維基材(2)及び裏打ち不織布(4)は、例えばポリエステルなどの合成繊維からなるものである。発泡層(1)は、例えば、分子内にカルボニル基及びカルボキシル基を含有するガラス転移点（Tg）-20℃程度のアクリル系共重合体微粒子の水性分散液に、アジピン酸ジヒドラジドなどのヒドラジン誘導体を該微粒子中のカルボニル基１当量に対して0.5当量、ラウリル硫酸ナトリウムなどの起泡剤を該微粒子100重量部当たり１重量部程度、ステアリン酸を主体とする高級脂肪酸のアンモニウム塩などの気泡安定剤を該微粒子100重量部当たり8.5重量部程度配合し、これにポリカルボン酸系増粘剤を適宜の量配合した後、25％アンモニア水を添加して5000〜20000 mPa・s増粘し、次いでこれを機械攪拌により、発泡前の組成物の容量に基づいて約３倍程度まで発泡したものを、ナイフコーターなどの塗工手段により、直接繊維基材(2)に、乾燥時の塗布量が200〜2000 g/m²程度の量となるように塗布し、その上に、直ちに裏打ち不織布(4)を重ねてから、熱風乾燥機等により、乾燥初期80℃前後、最終工程で150℃程度の温度で乾燥することによって形成される。こうした方法で発泡層(1)を形成することにより、パイル(3)の繊維基材(2)からの抜け落ちを防止することができると共に、該発泡層(1)を、別段の接着剤を解することなしに、該繊維基材(2)と裏打ち不織布(4)に強固に接合することができる。
【０１１４】
得られた発泡層(1)は、自動車の床面からの振動や騒音をできるだけ吸収するものとなることが好ましく、例えば、垂直入射吸音率法による周波数4000Hzでの吸音率が0.6以上、特には0.8以上となることが好ましい。
【０１１５】
滑り止め層(5)は、得られるオプションマット(10)を自動車の車内に敷設して使用するときに、人の足などによる外力によって簡単に滑って移動しない用にするために設けられるものであり、その材料はそのような機能に適合するものであれば必ずしも限定されるものではないが、例えば上記の発泡層(1)に用いられた組成物を発泡もしくは無発泡で、又はこの組成物にさらに適宜の無機質充填剤を加えたものを発泡もしくは無発泡で、裏打ち不織布(4)の背面に塗布し乾燥することにより形成することができる。滑り止め層(5)の乾燥時の塗布量は10〜100 g/m²程度の量であることが好ましい。
【０１１６】
【実施例】
以下、実施例により本発明を更に詳細に説明する。なお本実施例における試験方法及び評価方法は以下のとおりである。
【０１１７】
1. 試験シートの作成
1-1. 試験シート (1)
繊維基材として、坪量約310 g/m²、厚さ約５mmのポリエステル製スパンボンド不織布を用い、その一方の表面に所定のドクターブレードを用いて、発泡層形成用アクリル系共重合体水性組成物を所定倍率に発泡させたものを、湿時の塗布量が約600 g/m²になる様にドクターブレードのスリットを調整し塗布して、熱風循環式乾燥機中、80℃で30分間予備乾燥後、更に140℃で10分間乾燥して試験シート(1)とした。
【０１１８】
1-2. 試験シート (2)
試験シート(1)と同様に発泡層形成用アクリル系共重合体水性組成物の発泡させたものを塗布した後、その塗装面に、湿時、該繊維基材と同じ不織布を貼り合わせて、5.3 kg/m²の荷重をかけ、熱風循環式乾燥機中、80℃で30分間予備乾燥後、更に140℃で10分間乾燥して試験シート(2)とした。
【０１１９】
2. 発泡層の摩擦堅牢度
2-1. 常態堅牢度
前(1-1)項で作成した試験シート(1)を、23℃、60％RHの室内に１時間以上放置した後、学振型試験器を用いて以下の条件により測定した。
摩擦子 45R カナキン被覆（乾燥）
荷重 200g
回数 300回
評価の基準は次のとおり
○：表面層の損傷殆どなし。
△：表面層の損傷ややあり。
×：表面層の損傷著しい。
【０１２０】
2-2. 耐水堅牢度
前(1-1)項で作成した試験シート(1)を水に10分間浸漬した後、学振型試験器を用いて以下の条件で測定した。
摩擦子 45R カナキン被覆（水で充分に濡らす。）
荷重 200g
回数 100回
評価の基準は次のとおり
○ … 表面層の損傷殆どなし。
△ … 表面層の損傷ややあり。
× … 表面層の損傷著しい。
【０１２１】
3. 吸音性の評価
前(1-2)項で作成した試験シート(2)について、JIS A 1405-1998に準拠する方法により周波数800〜5000 Hzの垂直入射吸音率を測定し、周波数4000Hzにおける吸音率の値を吸音性の指針とした。
【０１２２】
周波数4000Hzにおける吸音率は、一般に0.3以上であることが必要であり、0.6以上であることが好ましく、0.8以上であることがさらに好ましい。
【０１２３】
4. 不織布基材接着力
前(1-2)項で作成した試験シート(2)について23℃、65％RHの恒温恒湿条件下に３時間以上放置した後、同条件下で常態剥離強度を測定した。測定にはテンシロンUYM-4100〔東洋ボールドウィン(株)製〕を用い、測定試験片は幅25mm、つかみ間隔100mmとし、引張速度は300mm／分とした。
【０１２４】
不織布基材への接着力は、一般に 600 g/25mm以上であることが好ましく、さらには 750 g/25mm以上、特には900 g/25mm以上であることが好ましい。
【０１２５】
5. 風合
前(1-2)項で作成した試験シート(2)について手触りにより風合を評価した。評価基準は次のとおり。
○：柔軟
△：やや硬い
×：硬い
【０１２６】
〔アクリル系共重合体微粒子の水性分散液の製造〕
製造例１
温度計、攪拌機、窒素導入管及び還流冷却器を備えた反応器内にイオン交換水30重量部を仕込み、内温を60℃に昇温させた。一方、別の容器にイオン交換水20重量部と、乳化重合用の界面活性剤（以下、単に乳化剤ということがある）として、「DKS NL-180」〔ポリオキシエチレン(n=22)ラウリルエーテル型ノニオン系界面活性剤（有効成分濃度100重量％）；第一工業製薬(株)製〕（NL180）３重量部及び「ハイテノール08E」〔ポリオキシエチレン(n=８)オレイルエーテル硫酸エステル型アニオン系界面活性剤（有効成分濃度約95重量％）；第一工業製薬(株)製〕（H08E）0.5重量部（有効成分量約0.48重量部）を仕込んで攪拌溶解して乳化剤水溶液を作成し、次いでこれに、カルボニル含有単量体(c)としてジアセトンアクリルアミド（DAAM）１重量部及び不飽和カルボン酸(d)としてイタコン酸（IA）１重量部を仕込んで攪拌溶解した。次にこの水溶液に、主単量体(a)としてブチルアクリレート（BA）40.3重量部及びエチルアクリレート（EA）47.7重量部、並びにシアン化ビニル単量体(b)としてアクリロニトリル（AN）10重量部よりなる単量体混合物を加えて攪拌し、単量体乳化液を得た。
【０１２７】
反応器の内容物を窒素気流下に攪拌しながら加熱し、反応器内の水温が60℃に達した時点で、重合開始剤及び還元剤として、４重量％過硫酸アンモニウム（APS）水溶液及び４重量％メタ重亜硫酸ナトリウム（SMBS）水溶液をそれぞれ1.67重量部添加した後、単量体乳化液並びに、４重量％過硫酸カリウム水溶液及び４重量％メタ重亜硫酸ナトリウムそれぞれ8.33重量部を逐次添加しながら60℃で約４時間重合反応を行った。重合反応終了後、同温度で約１時間攪拌を継続してから冷却し、次いで25重量％アンモニア水でpHを６〜８に調整してカルボニル基及びカルボキシル基含有アクリル系共重合体微粒子の水性分散液を得た。得られた該水性分散液は、固形分59.6重量％、pH7.1、粘度150mPa・s（25℃、BH型回転粘度計20rpm；特に示すものを除き以下同様）、分散粒子の平均粒子径290 nmであり、該アクリル系共重合体のTgは-20℃であった。
【０１２８】
製造例２
製造例１において、乳化剤水溶液のうちの５重量％を反応器内に仕込み、残り95重量％の乳化剤水溶液にDAAM及びIAを溶解して、この水溶液を用いて製造例１と同様に単量体乳化液を作成する以外は製造例１と同様にしてアクリル系共重合体微粒子の水性分散液を得た。使用した単量体及び乳化剤の組成を表１に、得られたアクリル系共重合体の水性分散液の固形分、pH、粘度及び分散粒子の平均粒子径、並びに該アクリル系共重合体のTgを表２に示した。
【０１２９】
製造例３〜７
製造例１において、カルボニル含有単量体(c)としてDAAMの使用量を変え又はこれを用いず、必要に応じて主単量体(a)のBA及びEA使用量を加減し、さらに必要に応じて共単量体(e)として官能性共単量体グリシジルメタクリレート（GMA）又はトリアリルシアヌレート（TAC）を併用する以外は製造例１と同様にして、Tgがほぼ同じアクリル系共重合体微粒子の水性分散液を得た。使用した単量体及び乳化剤の組成を表１に、得られた水性分散液の固形分、pH、粘度及び分散粒子の平均粒子径、並びに該アクリル系共重合体のTgを表２に示した。
【０１３０】
製造例８〜12
製造例１において、不飽和カルボン酸(d)の種類及び／もしくは使用量を変え、又はこれを使用せず、必要に応じて主単量体(a)のBA及びEA使用量を加減し及び／又はシアン化ビニル単量体の使用量を加減する以外は製造例１と同様にして、Tgがほぼ同じアクリル系共重合体微粒子の水性分散液を得た。使用した単量体及び乳化剤の組成を表１に、得られた水性分散液の固形分、pH、粘度及び分散粒子の平均粒子径、並びに該アクリル系共重合体のTgを表２に示した。但し、不飽和カルボン酸(d)としてアクリル酸（AA）又はメタクリル酸（MAA）を使用するときには、単量体乳化液の作成に際して、カルボニル含有単量体(c)及び乳化剤と共に水に溶解させて乳化剤水溶液とする代わりに、主単量体(a)及びシアン化ビニル単量体(b)とともに単量体混合物として、これを乳化剤水溶液に添加・攪拌して単量体乳化液とした。
【０１３１】
なおこれらのうち、不飽和カルボン酸単量体(b)を共重合していない製造例８のアクリル系共重合体微粒子の水性分散液は、凝集物が多く濾過が困難であり、また指でこするだけで簡単にエマルジョン破壊を起こすほど機械安定性が劣悪であった。一方、MAAをやや多く共重合した製造例12のアクリル系共重合体微粒子の水性分散液は、室温放置約１週間後に分散液全体がプリン状にゲル化を起こしていた。さらにDAAMをやや多く共重合した製造例７のアクリル系共重合体微粒子の水性分散液は、凝集物がやや多く濾過に時間がかかった。
【０１３２】
製造例13〜21
製造例１において、表１に示すように、主単量体(a)の種類及び／又は量を変え、シアン化ビニル単量体(b)の量を変え、必要に応じて、共単量体(e)を用い、乳化剤の種類を変え、さらに乳化剤水溶液の脱イオン水の量を加減する以外は製造例１と同様にして、Tgの異なるアクリル系共重合体の水性分散液を得た。使用した単量体及び乳化剤の組成を表１に、得られたアクリル系共重合体の水性分散液の固形分、pH、粘度及び分散粒子の平均粒子径、並びに該アクリル系共重合体のTgを表２に示した。
【０１３３】
なお、表１において用いられる単量体及び乳化剤の略号は次のとおりである。
EHA：2-エチルヘキシルアクリレート
BA：ブチルアクリレート
EA：エチルアクリレート
MMA：メチルメタクリレート
AN：アクリロニトリル
DAAM：ジアセトンアクリルアミド
AA：アクリル酸
MAA：メタクリル酸
IA：イタコン酸
St：スチレン
TAC：トリアリルシアヌレート
【０１３４】
NL180：「DKS NL180」（商品名）；ポリオキシエチレン(n=22)ラウリルルエーテル型ノニオン系界面活性剤（有効成分濃度100重量％）；第一工業製薬(株)製
NL250：「DKS NL250」（商品名）；ポリオキシエチレン(n=25)ラウリルルエーテル型ノニオン系界面活性剤（有効成分濃度100重量％）；第一工業製薬(株)製
NL450：「DKS NL450」（商品名）；ポリオキシエチレン(n=50)ラウリルルエーテル型ノニオン系界面活性剤（有効成分濃度100重量％）；第一工業製薬(株)製
Y500：「モノゲンY-500」（商品名）；ラウリル硫酸エステル塩型アニオン系界面活性剤（有効成分濃度100重量％）；第一工業製薬(株)製
No.6：「ネオペレックスNo.6」（商品名）；ドデシルベンゼンスルホン酸塩型アニオン系界面活性剤（有効成分濃度60重量％）；花王(株)製
H-08E：「ハイテノール-08E」（商品名）；ポリオキシエチレン(n=8)オレイルエーテル硫酸エステル塩型アニオン系界面活性剤（有効成分濃度95重量％）；第一工業製薬(株)製
【０１３５】
【表１】

【０１３６】
【表２】

【０１３７】
〔発泡層形成用アクリル系共重合体水性組成物の作製〕
実施例１
製造例１のアクリル系共重合体微粒子の水性分散液175重量部〔固形分約104.3重量部；共重合体として約100重量部；カルボニル基含有量約0.00592当量部（なお「当量部」とは、100重量部を100gと読み替えたときの当量数をもって表すものとする）〕に、ヒドラジン誘導体(B)としてアジピン酸ジヒドラジド（ADH）0.257重量部（約0.00299当量部；共重合体のカルボニル基１当量に対して約0.51当量）を添加して溶解させ、次に起泡剤(C)として「モノゲンY-500」の30％水溶液（Y500）11.7重量部、（有効成分量約3.5重量部）、気泡安定剤(D)として「ノプコDC-100-A」〔商品名；ステアリン酸アンモニウム；有効成分濃度33重量％；サンノプコ(株)製〕（DC100）8.7重量部（有効成分量約2.9重量部）を添加して、ディスパー型攪拌機を用い均一に混合した。次いで増粘剤として「ニカゾールVT-253A」〔商品名；ポリカルボン酸系樹脂水性分散液（有効成分濃度約27重量％）；日本カーバイド工業(株)製〕4.7重量部（有効成分量約1.3重量部）を加え、25％アンモニア水でpHを約8.5に調整し、固形分55.8重量％、粘度約10000mPa・sの発泡層形成用アクリル系共重合体水性組成物を得た。
【０１３８】
また別に、製造例１のアクリル系共重合体微粒子水性分散液175重量部にADH 0.26重量部を加えただけの組成物を作成し、前記に従って、架橋フィルムの動的粘弾性特性を測定したところ、ゴム状領域の上限が185℃にまで及んでいる優れた弾性を有する架橋フィルムを形成することが確認された。
【０１３９】
実施例２〜５及び比較例１
実施例１において、ADHの使用量を変えもしくはこれを用いず、又はADHを0.5当量比用いる代わりに炭酸ジヒドラジド（CDH）を0.5当量比用い、必要に応じて、起泡剤(C)、気泡安定剤(D)及び／又は増粘剤の量を加減する以外は実施例１とほぼ同様にして発泡層形成用アクリル系共重合体水性組成物を得た。また実施例１と同様にして、架橋フィルムの動的粘弾性特性を測定した。得られた組成物の配合組成を表３に、該組成物の特性値及び架橋フィルムの動的粘弾性特性を表４に示す。
【０１４０】
実施例６〜22及び比較例２〜４
実施例１において、製造例１のアクリル系共重合体微粒子水性分散液を用いる代わりに、製造例２〜21のアクリル系共重合体微粒子水性分散液を用い、またそれぞれのアクリル系共重合体微粒子中のカルボニル基１当量に対して、ADHの当量比0.5（但しカルボニル基当量０の製造例３では実施例１と同量）となるようにADHの使用量を調整し、必要に応じて、起泡剤(C)、気泡安定剤(D)及び／又は増粘剤の量を加減する以外は実施例１とほぼ同様にして発泡層形成用アクリル系共重合体水性組成物を得た。また実施例１と同様にして、架橋フィルムの動的粘弾性特性を測定した。得られた組成物の配合組成を表３に、該組成物の特性値及び架橋フィルムの動的粘弾性特性を表４に示す。
【０１４１】
実施例23〜25
実施例１において、無機化合物として無機質充填剤である水酸化アルミニウム〔BW-703；商品名；日本軽金属(株)製〕又は重質炭酸カルシウム〔R重炭；商品名；丸尾カルシウム(株)製〕をそれぞれ所定量用い、必要に応じて、起泡剤(C)、気泡安定剤(D)及び／又は増粘剤の量を加減する以外は実施例１とほぼ同様にして、発泡層形成用アクリル系共重合体水性組成物を得た。得られた組成物の配合組成を表３に、該組成物の特性値を表４に示す。
【０１４２】
なお、表３において用いられるヒドラジン誘導体及び無機化合物の略号は次のとおりである。
ADH：アジピン酸ジヒドラジド
CDH：炭酸ジヒドラジド
BW703：「BW-703」（商品名）；水酸化アルミニウム；日本軽金属(株)製
R重炭：「R重炭」（商品名）；重質炭酸カルシウム；丸尾カルシウム(株)製
【０１４３】
【表３】

【０１４４】
【表４】

【０１４５】
実施例31
容量約500 mLのポリエチレン製ビーカーに、実施例１で得られた発泡層形成用アクリル系共重合体水性組成物100gを計量して入れ、直径約３cm羽根のディスパー型攪拌機を用い高速攪拌にて気泡を混入しながら約３倍の容量となるまで発泡を行った。得られた発泡組成物の粘度は約21000 mPa・sであった。この発泡組成物を用いて、前記の方法に従い発泡層の密度を測定し、また前記(1-1)及び(1-2)の方法に従い試験シート(1)及び(2)を作成して、これらの試験シート(1)及び(2)を用いて前記の各種試験を行った。得られた発泡層は、その断面のルーペによる目視観察では連続気泡により形成されていることが確認され、その密度は約0.34 g/cm²であった。またこの試験シートの吸音性、基材接着力及び風合を表５に示す。
【０１４６】
実施例32〜33
実施例31において、必要に応じて使用する容器の大きさを変えて、発泡倍率を約1.5倍又は約６倍とする以外は実施例31と同様にして発泡組成物を得た。得られた発泡組成物を用いて前記の各種の試験を行った。発泡組成物の発泡倍率及び粘度、並びに得られた試験シートの発泡層密度及び各種物性を表５に示す。
【０１４７】
実施例34〜57及び比較例31〜34
実施例31において、実施例１の発泡層形成用アクリル系共重合体水性組成物を用いる代わりに、実施例２〜25及び比較例１〜４の発泡層形成用アクリル系共重合体水性組成物の何れかを用いる以外は、実施例31と同様にして発泡組成物を得た。得られた発泡組成物を用いて前記の各種の試験を行った。使用した発泡層形成用アクリル系共重合体水性組成物の種類及び得られた発泡組成物の粘度、並びに得られた試験シートの発泡層密度及び各種物性を表５に示す。
【０１４８】
なお比較例31の発泡組成物は、その中に凝集物をかなり含んでおり、試験シートの作成における繊維基材への塗布に際して、ノリすじが生じて平滑な発泡層表面が得られなかった。
【０１４９】
【表５】

【０１５０】
【発明の効果】
本発明の発泡層形成用アクリル系共重合体水性組成物は、カルボニル基及びカルボキシル基を含有し、特定のガラス転移点（Tg）を有するアクリル系共重合体の微粒子(A)、分子内に複数のヒドラジド残基を有するヒドラジン誘導体(B)、起泡剤(C)及び気泡安定剤(D)を含有してなるものである。
【０１５１】
上記のように構成することにより本発明の発泡層形成用アクリル系共重合体水性組成物は、天然繊維、再生繊維、合成繊維等からなる織布、編布、不織布、フェルト、紙など繊維基材に発泡層を形成するとき、熱により繊維基材を変形させるなどの不都合を生じさせることなく、乾燥温度程度の比較的低温で架橋を進行させることができ、且つホルムアルデヒドなど健康上有害な物質を発生させることがなく、その結果得られる発泡層を含む製品もホルムアルデヒドなどの有害物質を実質的に含まない堅牢なものとなる。特に本発明の組成物を自動車のフロアカーペットの上に部分的に載置する、所謂「オプションマット」中に発泡層を形成するために使用するときには、その発泡層は防音効果が高く、且つ繊維基材にパイル等が植設されているときにはその抜け止めの機能を兼ね、さらに発泡層の背面に保護層などを有するときには、その保護層の接着剤としての機能をも兼ねることもできる。
【図面の簡単な説明】
【図１】図１は、共重合体から形成されるフィルムの動的粘弾性特性を表す概念図である。
【図２】図２は、本発明のアクリル系共重合体の微粒子(A)とヒドラジン誘導体(B)の配合物より形成される架橋フィルム(x)と、従来のアクリル系共重合体の非架橋又は低架橋フィルム(y)の動的粘弾性特性を比較する概念図である。
【図３】図３は、本発明の発泡層形成用アクリル系共重合体水性組成物を用いて作製されるオプションマットの概念図である。
【符号の説明】
ｕ：ガラス状領域及び転移域を表す曲線の交点。
ｖ：転移域及びゴム状領域を表す曲線の交点。
ｗ：ゴム状領域及び流動域を表す曲線の交点。
Tu：ガラス状領域及び転移域を表す曲線の交点の温度、ガラス転移点（Tg）と等しいものとして定義する。
Tv：転移域及びゴム状領域を表す曲線の交点の温度。
Tw：ゴム状領域及び流動域を表す曲線の交点の温度、軟化点（Tm）と等しいものとして定義する。
ｘ：本発明のアクリル系共重合体の微粒子(A)とヒドラジン誘導体(B)の配合物より形成される架橋フィルム。
ｙ：従来のアクリル系共重合体の非架橋又は低架橋フィルム。
１：発泡層
２：繊維基材（マット）
３：パイル
４：裏打ち不織布
５：滑り止め層
１０：オプションマット[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an aqueous acrylic copolymer composition for forming a foam layer on a fiber base material such as woven fabric, knitted fabric, non-woven fabric, felt, paper such as natural fiber, regenerated fiber, synthetic fiber, etc. The present invention relates to an aqueous acrylic copolymer composition for forming a foamed layer in a so-called “option mat” structure that is partially placed on a floor carpet.
[0002]
In the processing and manufacture of products such as “option mat” using the acrylic copolymer aqueous composition for forming a foamed layer of the present invention, the drying temperature does not cause inconvenience such as deformation of the fiber substrate due to heat. Crosslinking can proceed at a relatively low temperature, and the foamed layer is cross-linked by carbonyl-hydrazide cross-linking that does not generate formaldehyde or other health hazards. The resulting product is also harmful to formaldehyde. Substantially free of substances, the foamed layer is robust and has a high soundproofing effect, and also functions as a stopper when piles are planted on the fiber base material. When a protective layer or the like is provided on the surface opposite to the contact surface with the fiber substrate, the protective layer can also function as an adhesive.
[0003]
Specifically, the acrylic copolymer fine particles (A) containing a carbonyl group and a carboxyl group and having a specific glass transition point (Tg), a hydrazine derivative (B) having a plurality of hydrazide residues in the molecule, The present invention relates to an aqueous acrylic copolymer composition for forming a foamed layer comprising a foaming agent (C) and a foam stabilizer (D).
[0004]
[Prior art]
Conventionally, it is well known that a so-called “option mat” is partially placed on a floor carpet in an automobile interior. Such an “option mat” is mainly placed on a portion where a person's foot comes into contact to prevent the carpet from being locally soiled or worn. Attempts have been made to provide a function to prevent noise from the floor surface of a car while it is running.
[0005]
For example, Patent Document 1 discloses a “piece mat” that has a pile structure and a flexibility that follows and adheres closely to a floor carpet, which is mainly composed of a low-density, multi-cavity sound-absorbing material adhered to the back surface thereof. Has been. This pile structure is made by planting a pile on a base fabric made of polyester fiber, etc., and applying latex processing on the back of the base fabric to prevent the pile from coming off. Sound absorbing materials are slab urethane foam, polyethylene foam, polyester It is stated that felts mainly composed of fibers are suitable. The invention described in Patent Document 1 discloses that an excellent sound absorbing effect is exhibited by such a configuration.
[0006]
However, Patent Document 1 does not describe the use of an acrylic copolymer as in the present invention as a foamed layer, and there is no suggestion about carbonyl-hydrazide crosslinking. In Patent Document 1, although the base fabric and the foamed layer are not particularly described, they must be bonded by some kind of adhesive, so that they are required for at least one extra step and cause an increase in cost.
[0007]
Patent Document 2 discloses a soundproof mat for automobiles in which a plurality of types of protrusions having different heights and shapes are formed on a backing layer provided on the back surface of a fiber sheet without gaps. The backing layer here is formed of a rubber polymer such as styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), butadiene rubber (BR), natural rubber (NR), isoprene rubber (IR), and the like. It is also disclosed that this backing layer can be designed to penetrate and solidify in the fiber sheet, which makes it possible to prevent the pile yarn of the fiber sheet from coming off.
[0008]
However, the backing layer in Patent Document 2 is not a foam layer, and the silencing mechanism is completely different from that of the present invention. The action of plural kinds of protrusions provided on the back surface of the backing layer and a part of the backing layer are contained in the fiber sheet. It is described that it is due to the action of different kinds of materials formed by osmotic solidification.
[0009]
Furthermore, Patent Document 3 discloses a sound insulating fiber sheet including a sound insulating layer made of a foamed resin layer having a closed cell structure whose surface is covered with a skin layer. The sound insulation layer uses a polymer such as styrene-butadiene-styrene (SBS), styrene-butadiene-rubber (SBR), polyurethane, acrylic, or polyvinyl chloride as a base resin, and is heated to gas such as sodium bicarbonate. A foaming agent that generates water is blended, vacuum degassed, and heated to form closed cells.
[0010]
On the other hand, the foam layer in the present invention does not use a gas generating foaming agent or the like, and is obtained by foaming an aqueous dispersion of an acrylic copolymer directly by means of mechanical stirring or the like. It is mainly composed of open cells formed by coating and drying as it is, and is completely different in structure from the sound insulation layer of Patent Document 3.
[0011]
An acrylic copolymer capable of forming a carbonyl-hydrazide bridge used in the present invention is also known. For example, Patent Document 4 discloses the use of an aqueous dispersion of a carbonyl group-containing copolymer containing a hydrazine derivative. Proposed.
[0012]
However, the aqueous dispersion disclosed in Patent Document 4 is used for coating, coating, impregnation and the like of adhesive raw materials, additives for hydraulic binders, paper coatings, fiber fleece binders, woven fabrics, knitted fabrics, leathers and the like. Although it is disclosed that it is used, there is no description or suggestion that it is used for forming a foamed layer and that the resulting foamed layer has excellent sound absorption.
[0013]
[Patent Document 1]
JP 2001-47926 A (claims, page 3, column 4, [0012], FIG. 3 and FIG. 7)
[Patent Document 2]
JP 2000-203353 (Claims, page 3, column 3 [0015] and [0016], page 4, column 5 [0027], FIGS. 1 and 2)
[Patent Document 3]
JP 2002-46203 A (claims, page 2, column 2 [0012] to page 3, column 3 [0014], page 3, column 3 [0016] to [0020], FIG. 3 and 5)
[Patent Document 4]
JP 54-144432 (Claims, page 4, lower right column, lines 12 to 16)
[0014]
[Problems to be Solved by the Invention]
The present inventors have developed a so-called “optional mat” structure that is partially placed on an acrylic copolymer aqueous composition for forming a foamed layer on various fiber substrates, in particular, on an automobile floor carpet. Acrylic copolymer aqueous composition for forming a foamed layer in the product, which can be obtained without producing harmful substances such as formaldehyde in the processing and manufacture of products such as "Option Mat" Acrylic copolymer water-based product that does not contain harmful substances such as formaldehyde, and can form a foam layer with excellent flexibility, fastness, water resistance, and excellent soundproofing effect. Research has been conducted to develop compositions.
[0015]
As a result, first, as a crosslinking system, a method of crosslinking a carbonyl group-containing acrylic copolymer that does not generate harmful substances such as formaldehyde with a hydrazine derivative was adopted, and a glass transition point (Tg) -20 having a carbonyl group and a carboxyl group was adopted. Aqueous dispersion of acrylic copolymer fine particles of about 0 ° C. is mixed with an aqueous solution of a hydrazine derivative having a plurality of hydrazide residues in the molecule such as adipic acid dihydrazide, and a foaming agent such as sodium lauryl sulfate and higher fatty acid ammonium. A composition containing a foam stabilizer such as salt is foamed approximately three times by mechanical foaming to produce an optional mat sample and tested for soundproofing effects. It has excellent performance. As a result, the present invention was completed.
[0016]
[Means for Solving the Problems]
According to the present invention, the following (A) to (D),
(A) Acrylic copolymer fine particles having a glass transition point (Tg) of −10 ° C. or less containing a carbonyl group and a carboxyl group,
(B) a hydrazine derivative having a plurality of hydrazide residues in the molecule,
(C) foaming agent, and
(D) Cell stabilizer,
There is provided an aqueous acrylic copolymer composition for forming a foamed layer.
The present invention will be described in detail below.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
[Acrylic copolymer fine particles (A) and aqueous dispersions thereof]
The aqueous acrylic copolymer composition for forming a foamed layer of the present invention contains an acrylic copolymer having a glass transition point (Tg) of −10 ° C. or lower, containing carbonyl groups and carboxyl groups in the molecule as main components. The fine particles (A). By containing these functional groups in the molecule, a crosslinked structure is formed with the hydrazine derivative (B) described later contained in this composition, and adhesion to the fiber substrate, sound absorption, flexibility, rebound resilience It is possible to form a foam layer that exhibits excellent performance such as fastness to friction and water resistance.
[0018]
The content of these functional groups is not necessarily limited, and can be appropriately selected depending on the use of the obtained composition and the glass transition point (Tg) of the copolymer. Based on the weight of the fine particles (A), the amount of the repeating unit having a carbonyl group in the side chain is preferably in the range of 0.1 to 5% by weight, more preferably 0.2 to 3% by weight, still more preferably 0.3 to 2% by weight. The amount of the repeating unit having a carboxyl group in the side chain is preferably in the range of 0.5 to 10% by weight, more preferably 0.6 to 6% by weight, still more preferably 0.8 to 4% by weight. Is good.
[0019]
Further, the acrylic copolymer needs to have a glass transition point (Tg) of −10 ° C. or lower, and is preferably in the range of −15 to −40 ° C. If the Tg exceeds the upper limit temperature and is too high, the sound absorption and flexibility of the foamed layer to be obtained tend to be impaired, which is not preferable. On the other hand, if Tg is equal to or higher than the lower limit temperature, the adhesiveness of the foamed layer to the fiber substrate, the fastness to friction, and the resilience are excellent.
[0020]
In the present invention, the glass transition point (Tg) of the acrylic copolymer is a value measured by the following.
[0021]
Glass transition point ( Tg ):
About 10 mg of an acrylic copolymer aqueous dispersion was weighed into a cylindrical cell made of aluminum foil with a thickness of about 0.05 mm and an inner diameter of about 5 mm and a depth of about 5 mm, and dried at 100 ° C. for 2 hours. A sample is used as a measurement sample. Using an SSC-5000 type differential scanning calorimeter manufactured by Seiko Denshi Kogyo Co., Ltd., the temperature is measured from −150 ° C. at a heating rate of 10 ° C./min.
[0022]
In the present specification, the term “acrylic copolymer” is usually used to indicate a copolymer derived from an acrylic ester or a monomer containing 50 wt% or more of an acrylic ester and a methacrylic ester. It is done.
[0023]
The acrylic copolymer fine particles (A) used in the present invention are specifically represented by the general formula as essential monomers.
H₂C = CR¹-COOR²    (1)
(However, R in the formula¹Is hydrogen or methyl group, R²Represents a linear or branched alkyl group having 1 to 10 carbon atoms)
Monomer (a) [hereinafter sometimes referred to as main monomer (a)], vinyl cyanide monomer (b), carbonyl group-containing monomer (c), and 3 to 5 carbon atoms. Formed of an acrylic copolymer obtained by emulsion copolymerization of α, β-unsaturated mono- or di-carboxylic acid (d) (hereinafter sometimes simply referred to as unsaturated carboxylic acid (d)). Is preferred.
[0024]
As such a main monomer (a), R in the general formula (1)¹Is hydrogen and R²Is a monomer having a linear or branched alkyl group having 1 to 10 carbon atoms, specifically, methyl acrylate, ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, i-butyl acrylate Acrylic acid ester monomers such as t-butyl acrylate, n-octyl acrylate, i-octyl acrylate, 2-ethylhexyl acrylate, n-nonyl acrylate, i-nonyl acrylate, n-decyl acrylate; R in¹Is a methyl group and X is COOR²And R²Is a monomer having a linear or branched alkyl group having 1 to 12 carbon atoms, specifically, methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, and n-decyl methacrylate. Monomer; and the like.
[0025]
Among these main monomers (a), copolymerization with other monomers, polymerization stability, and viewpoints of good washing resistance of textile products processed using the resulting cross-linked resin aqueous composition Therefore, it is particularly preferable to use butyl acrylate, ethyl acrylate or methyl methacrylate.
[0026]
The amount of the main monomer (a) used is the weight of the desired acrylic copolymer fine particles (A), that is, the total of the monomers (a) to (e) constituting the fine particles (A). Based on 100% by weight, it is preferably 50 to 94.4% by weight, more preferably 60 to 90% by weight, and even more preferably 70 to 85% by weight. If the amount of the main monomer (a) used is not less than the lower limit value, it is preferable because the resulting foamed layer has excellent adhesion to the fiber substrate, sound absorption, water resistance and the like. If the amount is not more than the upper limit, a relatively large amount of the vinyl cyanide monomer (b), the carbonyl group-containing monomer (c) and / or the unsaturated carboxylic acid (d) can be used. The foam layer is preferable because it has excellent friction fastness, rebound resilience, sound absorption and the like.
[0027]
Examples of the vinyl cyanide monomer that is the essential monomer (b) include acrylonitrile and methacrylonitrile. The amount of the monomer (b) used is preferably 5 to 23% by weight, more preferably 6 to 22% by weight, based on a total of 100% by weight of the monomers (a) to (e). Preferably it is 7 to 20 weight%. If the amount of the monomer (b) used is not less than the lower limit, the resulting foamed layer is preferably excellent in rebound resilience and sound absorption, and if not more than the upper limit, the foamed layer is preferred. This is preferable because of its excellent flexibility, water resistance, sound absorption and the like.
[0028]
The carbonyl group-containing monomer as the essential monomer (c) is a monomer having at least one aldo group or keto group and one polymerizable double bond in the molecule, that is, in particular Polymerizable monoethylenically unsaturated aldo and keto compounds having only an ester bond (—COO—), an amide bond (—CONH—) or a carboxyl group (—COOH) are excluded.
[0029]
Specific examples of such monomers include, for example, acrolein, diacetone acrylamide, diacetone methacrylamide, formyl styrene, vinyl methyl ketone, vinyl ethyl ketone, vinyl isobutyl ketone, (meth) acryloxyalkylpropanal, diacetone. Mention may be made of acetone acrylate, acetonyl acrylate, diacetone acrylate, diacetone methacrylate, 2-hydroxypropyl acrylate-acetyl acetate, butanediol-1,4-acrylate-acetyl acetate. Among these, diacetone acrylamide and vinyl methyl ketone are preferable, and diacetone acrylamide is particularly preferable from the viewpoints of availability, ease of polymerization reaction operation, and the like.
[0030]
The amount of the carbonyl group-containing monomer (c) used is preferably 0.1 to 5% by weight, more preferably 0.2 to 3% by weight, based on a total of 100% by weight of the monomers (a) to (e). %, More preferably in the range of 0.3 to 2% by weight. If the amount of the monomer (c) used is not less than the lower limit, it is preferable because the resulting foam layer has excellent friction fastness, rebound resilience, sound absorption, etc. If present, the emulsion stability of the acrylic copolymer is preferable since the polymerization stability is not impaired and the adhesion of the resulting foamed layer to the fiber base material is improved.
[0031]
Examples of the essential monomer (d) α, β-unsaturated mono- or di-carboxylic acid (unsaturated carboxylic acid) having 3 to 5 carbon atoms include acrylic acid, methacrylic acid, itaconic acid and maleic acid. Acid, fumaric acid, crotonic acid, citraconic acid and the like can be mentioned. Among these, the use of acrylic acid, methacrylic acid and itaconic acid is preferable from the viewpoints of polymerization stability during emulsion polymerization of the acrylic copolymer, and excellent mechanical stability of the aqueous dispersion obtained. The use of itaconic acid is particularly preferred from the viewpoint of the excellent foam layer elasticity of the resulting foamed acrylic aqueous copolymer composition.
[0032]
The amount of the unsaturated carboxylic acid (d) used is preferably 0.5 to 10% by weight, more preferably 0.6 to 6% by weight, based on a total of 100% by weight of the monomers (a) to (e). Preferably it is 0.8 to 4 weight% of range. If the amount of unsaturated carboxylic acid (d) used is less than or equal to the upper limit, polymerization stability may be impaired during copolymerization, or the copolymer aqueous dispersion may thicken abnormally or cause gelation during storage. This is preferable because it is less likely to cause inconveniences such as, and the water resistance of the resulting foamed layer is less likely to occur. If the amount used is not less than the lower limit, the aqueous dispersion of the acrylic copolymer fine particles obtained and the storage stability and mechanical stability of the aqueous acrylic copolymer composition for forming a foamed layer (dispersion should be used). Dispersion fracture resistance when a narrow gap is filled and a shear force is applied is excellent, and it is easy to increase the viscosity to a preferred viscosity range when the aqueous composition is mechanically foamed.
[0033]
The monomer (e) used as necessary is copolymerizable with the monomers (a) to (d), and a comonomer other than the monomers (a) to (d). Is the body. Specific examples of such a monomer include saturated fatty acid vinyl esters such as vinyl formate, vinyl acetate, vinyl propionate, “vinyl versatate” (trade name) (preferably vinyl acetate); for example, styrene, α- Aromatic vinyl monomers such as methylstyrene and vinyltoluene (preferably styrene);
[0034]
Further, the comonomer (e) is a monomer having at least one functional group in addition to one radical polymerizable unsaturated group in the molecule, if necessary. Monomers other than the bodies (b) and (c) (hereinafter sometimes referred to as functional comonomers) can also be copolymerized.
[0035]
Examples of such a functional comonomer include a functional group such as an amide group or a substituted amide group, an amino group or a substituted amino group, a hydroxyl group, a lower alkoxyl group, an epoxy group, a mercapto group, or a silicon-containing group. The monomer which has 2 or more of radically polymerizable unsaturated groups in a molecule | numerator can also be used.
[0036]
Specific examples of these functional comonomers include acrylamide, methacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, Nn-butoxymethylacrylamide, Ni-butoxymethylacrylamide, N, N-dimethylacrylamide, N- Amide group or substituted amide group-containing monomer such as methyl acrylamide; for example, aminoethyl acrylate, N, N-dimethylaminoethyl acrylate, N, N-diethylaminoethyl acrylate, N, N-dimethylaminoethyl methacrylate, N, N -Amino group or substituted amino group-containing monomers such as diethylaminoethyl methacrylate;
[0037]
For example, hydroxyl group-containing monomers such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, allyl alcohol, methallyl alcohol, polyethylene glycol monoacrylate, polyethylene glycol monomethacrylate For example, 2-methoxyethyl acrylate, 2-ethoxyethyl acrylate, 2-n-butoxyethyl acrylate, 2-methoxyethoxyethyl acrylate, 2-ethoxyethoxyethyl acrylate, 2-n-butoxyethoxyethyl acrylate, 2-methoxyethyl Methacrylate, 2-ethoxyethyl methacrylate, 2-n-butoxyethyl methacrylate, 2-methoxyethoxyethyl methacrylate, 2-ethoxyethoxyethyl methacrylate Over preparative, 2-n-butoxyethoxy ethyl methacrylate, methoxy polyethylene glycol monoacrylate, lower alkoxyl group-containing monomers such as methoxy polyethylene glycol monomethacrylate;
[0038]
For example, epoxy group-containing monomers such as glycidyl acrylate, glycidyl methacrylate, glycidyl allyl ether, glycidyl methallyl ether; mercapto group-containing monomers such as allyl mercaptan;
[0039]
For example, vinyltrichlorosilane, vinyltribromosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri-n-propoxysilane, vinyltri-i-propoxysilane, vinyltri-n-butoxysilane, vinyltris (2-methoxyethoxy) silane , Vinyltris (2-hydroxymethoxyethoxy) silane, vinyltriacetoxysilane, vinyldiethoxysilanol, vinylethoxysiladiol, vinylmethyldiethoxysilane, vinyldimethylethoxysilane, vinylmethyldiacetoxysilane, allyltrimethoxysilane, allyltri Ethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxysilane, 3-methacryloxypropyltris (2-methoxyethoxy) silane, 3-methacryloxy Propyl methyl diethoxy silane, 3-methacryloxypropyl dimethyl ethoxysilane, 3-acryloxypropyl dimethyl methoxy silane, a monomer having a silicon-containing group, such as 2-acrylamide-ethyl triethoxysilane;
[0040]
For example, divinylbenzene, diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, ethylene glycol di (meth) acrylate, 1,2-propylene glycol di (meth) acrylate, 1,3-propylene glycol di (meth) acrylate, 2,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, allyl (meth) acrylate, etc. A monomer group such as a monomer having one or more radically polymerizable unsaturated groups;
[0041]
The amount of the comonomer (e) used is generally 0 to 20% by weight, preferably 0 to 15% by weight, based on 100% by weight of the monomers (a) to (e). Particularly preferably, it is in the range of 0 to 10% by weight. The amount of the comonomer (e) used varies depending on the type of the monomer (e) and cannot be uniquely determined, but the excellent performance of the resulting acrylic copolymer aqueous composition for forming a foam layer of the present invention is impaired. The amount can be appropriately selected within the above range. If the amount of the comonomer (e) used is less than or equal to the upper limit of the above range, the emulsion polymerization stability and the stability of the aqueous dispersion of the resulting copolymer fine particles are excellent, and the foaming obtained is It is preferable because the water resistance of the layer is also good. Further, when the amount used is within the above range, the storage stability and mechanical stability of the aqueous dispersion of copolymer fine particles are not impaired, and the resulting foam layer has fast friction, sound absorption, and water resistance. Improvements in properties such as rebound resilience and adhesion to fiber substrates can be expected.
[0042]
As a preferred method for producing the acrylic copolymer fine particles (A) used in the present invention, for example, the monomers (a) to (e) may be used in the presence of a water-soluble protective colloid as necessary. Examples of the emulsion copolymerization in an aqueous medium using an appropriate surfactant as an emulsifier for polymerization can be given.
[0043]
In the present invention, surfactants that can be used for emulsion copolymerization include, as nonionic surfactants, for example, aliphatic alcohol polyoxyethylene ethers having 10 to 20 carbon atoms represented by the following general formula (2): Type nonionic surfactants can be used.
R^ThreeO (EO)_nH (2)
(Where R^ThreeIs a linear or branched alkyl or alkenyl group having 8 to 20 carbon atoms in which part of hydrogen bonded to the carbon chain may be substituted with fluorine or a hydroxyl group, EO represents a divalent ethylene oxide group )
[0044]
Suitable nonionic surfactants represented by the general formula (2) include, for example, polyoxyethylene decyl ether, polyoxyethylene undecyl ether, polyoxyethylene dodecyl ether, polyoxyethylene lauryl ether, polyoxyethylene parylene. Examples thereof include polyoxyethylene alkyl ethers such as mytyl ether and polyoxyethylene stearyl ether (preferably polyoxyethylene lauryl ether), and polyoxyethylene alkenyl ethers such as polyoxyethylene oleyl ether.
[0045]
Further, the length (value of n) of the polyoxyethylene chain in the nonionic surfactant is preferably in the range of 10 to 120, more preferably in the range of 15 to 100, and still more preferably in the range of 17 to 90. It is good to be. If the value of n is within this range, it is preferable because there is little generation of aggregates during aqueous emulsion polymerization, and the resulting aqueous dispersion has good mechanical and chemical stability.
[0046]
In the emulsion copolymerization of the acrylic copolymer of the present invention, in addition to the nonionic surfactant represented by the general formula (2), for example, polyoxyethylene octyl phenyl ether, polyoxyethylene nonyl phenyl ether, etc. Polyoxyethylene alkylphenyl ethers; for example, sorbitan higher fatty acid esters such as sorbitan monolaurate, sorbitan monostearate, sorbitan trioleate; for example, polyoxyethylene sorbitan higher fatty acid esters such as polyoxyethylene sorbitan monolaurate For example, polyoxyethylene higher fatty acid esters such as polyoxyethylene monolaurate and polyoxyethylene monostearate; for example, glycerin such as oleic acid monoglyceride and stearic acid monoglyceride Grade fatty acid esters; e.g., polyoxyethylene-polyoxypropylene block copolymer; for example, polyoxyethylene alkyl (or alkenyl) ether dialkyl orthophosphoric acid esters; it is also possible to use such. These nonionic surfactants can be used alone or in combination of two or more.
[0047]
Furthermore, in the emulsion copolymerization of the acrylic copolymer used in the present invention, a so-called “reactive emulsifier” having an unsaturated group capable of radical polymerization in the molecule can be used as necessary.
[0048]
Among these, nonionic reactive emulsifiers include, for example, “AQUALON RN-20”, “AQUALON RN-30”, “AQUALON RN-50” (above, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), “Adekaria soap” NE-10, ADEKA rear soap NE-20, ADEKA rear soap NE-30 (Asahi Denka Kogyo Co., Ltd.), RMA-564, RMA-568, RMA-1114 [ As mentioned above, Nippon Emulsifier Co., Ltd.] and the like can be mentioned.
[0049]
The amount of these nonionic surfactants used is 100 parts by weight of the acrylic copolymer fine particles (A) obtained, that is, 100 parts by weight in total of the monomers (a) to (e). The active ingredient is preferably 0.6 to 10 parts by weight, particularly preferably 1 to 6 parts by weight. If the amount of the nonionic surfactant used is less than or equal to the upper limit, the fiber base of the composition coating based on the aqueous copolymer dispersion obtained while having good polymerization stability during aqueous emulsion copolymerization It is preferable because the foamed layer obtained does not impair the adhesion to the surface and has excellent water resistance. On the other hand, if it is at least the lower limit value, it may cause inconveniences such as generation of aggregates in the aqueous emulsion copolymerization, destruction of the emulsified state, reduction in storage stability and mechanical stability of the resulting aqueous dispersion. It is preferable because it is not present.
[0050]
In the emulsion polymerization of the acrylic copolymer in the present invention, an anionic surfactant can be used in combination with the nonionic surfactant.
[0051]
As such an anionic surfactant, for example, the following general formula (3),
R^ThreeO (EO)_mSO_Four ^- M⁺    (3)
(In the formula, R^ThreeAnd EO are as defined in the general formula (2), and M⁺Is Na⁺, K⁺Or NH_Four ⁺Represents a monovalent counter ion, etc.)
A polyoxyethylene alkyl or alkenyl ether sulfate ester type anionic surfactant represented by the formula is preferably used.
[0052]
Suitable anionic surfactants represented by the general formula (3) include, for example, polyoxyethylene decyl ether sulfate ester salt, polyoxyethylene undecyl ether sulfate ester salt, polyoxyethylene dodecyl ether sulfate ester salt, polyoxyethylene dodecyl ether sulfate ester salt, Polyoxyethylene lauryl ether sulfate, polyoxyethylene palmityl ether sulfate, polyoxyethylene alkyl ether sulfate such as polyoxyethylene stearyl ether sulfate, and polyoxyethylene oleyl ether sulfate such as polyoxyethylene oleyl ether sulfate Examples thereof include ethylene alkenyl ether sulfate ester salts.
[0053]
Further, the length (value of m) of the polyoxyethylene chain in the above anionic surfactant is preferably in the range of 5-50, more preferably in the range of 10-40, and still more preferably in the range of 15-30. It is good to be.
[0054]
As an anionic surfactant that can be used in the present invention, the following general formula (4),
[0055]
[Chemical 1]

(In the formula, R^FourRepresents an alkyl group having 10 to 20 carbon atoms, M⁺Is as defined in general formula (3)]
[0056]
The alkylaryl sulfonate type anionic surfactant shown by these can be illustrated, Specifically, sodium dodecylbenzenesulfonate etc. can be illustrated.
[0057]
Examples of the anionic surfactant that can be used in the present invention include the following general formula (5),
[0058]
[Chemical formula 2]

(In the formula, R^FiveIs a hydrocarbon group containing one or more aromatic rings, EO is the general formula (2), M⁺Is as defined in general formula (3)]
[0059]
R in the general formula (5)^FiveIs preferably derived from any of distyryl represented by the following three structural formulas or a mixture thereof.
[0060]
[Chemical 3]

[0061]
The length (value of p) of the polyoxyethylene chain in the anionic surfactant is generally in the range of 4 to 50, and preferably in the range of 5 to 45.
[0062]
Specific examples of the anionic surfactant represented by the general formula (5) include, for example, Hightenol NF-13, Hightenol NF-17 [trade name; manufactured by Daiichi Kogyo Seiyaku Co., Ltd.], New Coal 707SF, New Coal 710SF, New Coal 714SF, New Coal 723SF, New Coal 740SF [trade name; manufactured by Nippon Emulsifier Co., Ltd.] and the like.
[0063]
Moreover, what substituted a part of hydrogen of the alkyl group of these emulsifiers with the fluorine can be used.
[0064]
Examples of the anionic surfactant that can be used in the present invention include higher fatty acid salts such as sodium oleate and sodium stearate; for example, sodium monooctylsulfosuccinate, sodium dioctylsulfosuccinate, polyoxyethylene laurylsulfosuccinate. Examples thereof include alkylsulfosuccinic acid ester salts such as sodium acid salt and derivatives thereof;
[0065]
Furthermore, as anionic reactive emulsifiers, for example, “Eleminol JS-2”, “Eleminol RS-30” (manufactured by Sanyo Chemical Industries, Ltd.), “AQUALON HS-10N”, “AQUALON HS-20N” [more , Daiichi Kogyo Seiyaku Co., Ltd.), `` Adekaria Soap SE-10N '' (Asahi Denka Kogyo Co., Ltd.), `` Latemuru S-120 '', `` Latemuru S-120A '', `` Latemuru S-180 '', “Latemul S-180A” (manufactured by Kao Corporation) can also be used.
[0066]
These anionic surfactants can be used alone or in combination of two or more, and the amount used is 100 parts by weight of the acrylic copolymer fine particles (A) obtained, that is, The amount of the active ingredient is preferably 5 parts by weight or less, particularly preferably 0.1 to 2 parts by weight, based on 100 parts by weight of the total amount of the monomers (a) to (e). If the amount of the anionic surfactant used is less than or equal to the upper limit, it is preferable because the resulting aqueous dispersion has good mechanical stability and chemical stability. Further, by using the lower limit value or more, there is a possibility of preventing the formation of aggregates and destruction of the emulsified state during aqueous emulsion polymerization and improving the storage stability and mechanical stability of the resulting aqueous dispersion. Therefore, it is preferable.
[0067]
Furthermore, the proportion of the anionic surfactant used is preferably 40% by weight or less in terms of the active ingredient ratio with respect to the total amount of the surfactant used, and is within the range of 5 to 30% by weight. Is more preferable. If the use ratio is not more than the upper limit value, it is preferable because the obtained aqueous dispersion is excellent in chemical stability. Moreover, it is preferable to use more than the lower limit value because it is possible to improve the storage stability and mechanical stability of the aqueous dispersion obtained by generating aggregates and destroying the emulsion state during emulsion polymerization.
[0068]
Furthermore, the amount of the total surfactant used in the emulsion copolymerization of the acrylic copolymer in the present invention is 100 parts by weight of the acrylic copolymer fine particles (A), that is, the monomer (a ) To (e) with respect to a total of 100 parts by weight, the active ingredient is preferably in the range of 1 to 10 parts by weight, more preferably in the range of 1.5 to 8 parts by weight, and 2.5 to 7 parts by weight. A range is particularly preferred. If the use ratio is less than or equal to the upper limit, the emulsion polymerization stability is excellent, the resulting aqueous dispersion is excellent in mechanical stability and chemical stability, and the composition coating based on the aqueous dispersion is used. Since it does not inhibit the adhesiveness to the base material, it is preferable. Moreover, it is preferable to use more than the lower limit value because it is possible to improve the storage stability and mechanical stability of the aqueous dispersion obtained by generating aggregates and destroying the emulsion state during emulsion polymerization.
[0069]
Furthermore, recently, when surfactants containing alkylphenyl groups, which are widely used in aqueous dispersions of acrylic copolymers, are contained in wastewater and discharged into rivers, etc., these surfactants are hydrolyzed. Alkylphenols generated by decomposition are taken up by organisms that live in these rivers and the seas into which they flow, especially fish and shellfish, and act as substances that destroy the endocrine function (endocrine) of these organisms (so-called environmental hormones). Became known. It has been pointed out that such alkylphenols have a high risk of entering the human body through the intake of these fishery products, or directly through the water of the waterworks that use water such as rivers.
[0070]
In the present invention, among the above nonionic and anionic surfactants, an acrylic copolymer aqueous solution that has solved the above-mentioned problems by selecting and using one that does not contain an alkylphenyl group as described above. A dispersion can also be obtained.
[0071]
Such surfactants include, as nonionic surfactants, aliphatic alcohol polyoxyethylene ethers having 10 to 20 carbon atoms represented by the general formula (2), sorbitan higher fatty acid esters, polyoxyethylene Use sorbitan higher fatty acid esters, polyoxyethylene higher fatty acid esters, glycerin higher fatty acid esters, polyoxyethylene / polyoxypropylene block copolymers, polyoxyethylene alkyl (or alkenyl) ether dialkyl orthophosphates, etc. be able to. Examples of the anionic surfactants include polyoxyethylene alkyl or alkenyl ether sulfates represented by the general formula (3), alkylaryl sulfonates represented by the general formula (4), and alkyl (or alkenyl). Sulfuric acid ester salts, polyoxyethylene alkyl (or alkenyl) ether sulfuric acid ester salts, alkyl (or alkenyl) sulfosuccinic acid ester salts and derivatives thereof, alkyl (or alkenyl) phosphoric acid ester salts, polyoxyethylene alkyl ether phosphoric acid ester salts The polyoxyethylene polycyclic phenyl ether type surfactant represented by the general formula (5) can be used.
[0072]
When these surfactants are used as an emulsifier for polymerization, they are preferably combined in an appropriate amount and used within the above-mentioned range of use.
[0073]
In the emulsion copolymerization of the water-based acrylic copolymer fine particles (A) in the present invention, together with the nonionic and anionic surfactants described above, protection is performed as necessary and within the range not impairing the excellent effects of the present invention. Colloids can be used in combination.
[0074]
Examples of such protective colloids include polyvinyl alcohols such as partially saponified polyvinyl alcohol, fully saponified polyvinyl alcohol, and modified polyvinyl alcohol; cellulose derivatives such as hydroxyethyl cellulose, hydroxypropyl cellulose, and carboxymethyl cellulose salt; and guar gum Natural polysaccharides such as; and the like. Examples of the use amount of these protective colloids include an amount of about 0 to 3 parts by weight with respect to 100 parts by weight of the acrylic copolymer fine particles (A).
[0075]
In the emulsion polymerization of the acrylic copolymer in the present invention, as a polymerization initiator, for example, persulfates such as ammonium persulfate, potassium persulfate, sodium persulfate; t-butyl hydroperoxide, cumene hydroperoxide, p-menthane Organic peroxides such as hydroperoxide; hydrogen peroxide; and the like can be used singly or in combination. The amount of the polymerization initiator used can be appropriately selected. For example, it is about 0.05 to 1 part by weight, more preferably about 0.1 to 0.7 part by weight, particularly preferably 100 parts by weight of the acrylic copolymer fine particles (A). Can be used in an amount of about 0.1 to 0.5 parts by weight.
[0076]
In the emulsion polymerization, a reducing agent can be used in combination as desired. Examples of the reducing agent include reducing organic compounds such as ascorbic acid, tartaric acid, citric acid, and glucose; and reducing inorganic compounds such as sodium thiosulfate, sodium sulfite, sodium bisulfite, and sodium metabisulfite. . Although the usage-amount of a reducing agent can be selected suitably, For example, usage-amounts, such as about 0.05-1 weight part with respect to 100 weight part of microparticles | fine-particles (A) of an acryl-type copolymer, can be illustrated.
[0077]
Furthermore, a chain transfer agent can be used as desired in the emulsion polymerization. Examples of such a chain transfer agent include cyanoacetic acid; C1-C8 alkyl esters of cyanoacetic acid; bromoacetic acid; C1-C8 alkyl esters of bromoacetic acid; for example, anthracene, phenanthrene, fluorene, 9 -Aromatic compounds such as phenyl fluorene; for example, aromatic nitro compounds such as p-nitroaniline, nitrobenzene, dinitrobenzene, p-nitrobenzoic acid, p-nitrophenol, p-nitrotoluene; Benzoquinone derivatives such as 3,5,6-tetramethyl-p-benzoquinone; borane derivatives such as tributylborane; for example, carbon tetrabromide, carbon tetrachloride, 1,1,2,2-tetrabromoethane, tribromo Halogenated coals such as ethylene, trichloroethylene, bromotrichloromethane, tribromomethane, 3-chloro-1-propene Hydrogen; for example, aldehydes such as chloral and furaldehyde; alkyl mercaptans having 1 to 18 carbon atoms; for example, aromatic mercaptans such as thiophenol and toluene mercaptan; mercaptoacetic acid; 1 to 10 alkyl esters of mercaptoacetic acid C1-12 hydroxyalkyl mercaptans; for example, terpenes such as vinylene and terpinolene;
[0078]
When the chain transfer agent is used, the amount used is preferably about 0.005 to 3 parts by weight with respect to 100 parts by weight of the acrylic copolymer fine particles (A).
[0079]
In a preferred embodiment of the emulsion copolymerization, the monomers (a) to (e), the surfactant, and the surfactant are contained in an aqueous medium containing or not containing the surfactant and / or protective colloid. And the aspect which adds a protective colloid, a polymerization initiator, and the reducing agent used as needed sequentially can be illustrated. The copolymerization temperature is about 40 to 100 ° C, preferably about 50 to 90 ° C.
[0080]
The aqueous dispersion of the acrylic copolymer fine particles (A) thus obtained can be adjusted in pH with aqueous ammonia or the like, if necessary. Such a dispersion usually has a solid content of 30 to 65% by weight, a viscosity of 10 to 3000 mPa · s (BH type rotational viscometer, 25 ° C., 20 rpm; the same applies to the viscosity measurement conditions below), and a pH of about 2 to 9. However, the stability of emulsion copolymerization of acrylic copolymers, the mechanical stability of the resulting copolymer aqueous dispersion, the storage stability, and the excellent compoundability of various additives in preparing the composition of the present invention For reasons such as this, the solid content concentration is preferably 50 to 65% by weight. The average particle size of the acrylic copolymer fine particles in the aqueous medium is preferably 200 to 500 nm, more preferably 230 to 350 nm. If the average particle size is not less than the lower limit, a copolymer aqueous dispersion having a relatively low viscosity and a high solid content can be easily obtained, and the miscibility with various additives becomes excellent. If it is below the upper limit value, the reactivity during emulsion polymerization is not hindered, and the storage stability of the resulting emulsion is good, which is preferable.
[0081]
In this specification, the average particle size of the copolymer dispersed particles is the “New Experimental Chemistry Lecture 4 Basic Technology 3 Hikari (II)” pages 725 to 741 edited by the Chemical Society of Japan (July 20, 1977 Maruzen Co., Ltd.) A value measured by a dynamic light scattering method (hereinafter also referred to as a DLS method) described in the company), and specifically a value measured by the method described below.
[0082]
Average particle size:
Dilute the copolymer aqueous dispersion 50,000 to 150,000 times with distilled water, mix well with stirring, and collect about 10 ml with a Pasteur pipette in a 21 mmφ glass cell. It is set at a predetermined position of the total “DLS-700” (manufactured by Otsuka Electronics Co., Ltd.), measured under the following measurement conditions, and the measurement result is computer processed to determine the average particle size.
[0083]
〔Measurement condition〕
Measurement temperature 24-26 ℃
Clock rate 10μsec
Correlation channel 512
200 integrated measurements
Light scattering angle 90 °
[0084]
[Acrylic copolymer aqueous composition for forming foam layer]
The aqueous acrylic copolymer composition for forming a foamed layer according to the present invention includes a hydrazine derivative (B) having a plurality of hydrazide residues in the molecule together with the aqueous dispersion of the acrylic copolymer fine particles (A) described above. It contains. As a result, the aqueous copolymer composition of the present invention can be processed under relatively mild processing conditions as described above, does not generate harmful substances such as formaldehyde, and can be obtained into a fiber base material of a foam layer. The properties such as adhesion, sound absorption, flexibility, rebound resilience, fastness to friction, and water resistance can be improved.
[0085]
The hydrazine derivative (B) that can be used in the present invention is not necessarily limited, but is preferably one that dissolves 1 part by weight or more with respect to 100 parts by weight of water, and an organic compound having 2 to 10 carbon atoms. A compound is preferred. Examples of such hydrazine derivatives (B) include oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, maleic acid dihydrazide, fumaric acid dihydrazide, and itaconic acid dihydrazide. Dihydrazide of dicarboxylic acid containing 2 to 10; for example, water-soluble C 2 to C 4 such as ethylene-1,2-dihydrazine, propylene-1,3-dihydrazine, butylene-1,4-dihydrazine Organic dihydrazine containing Of these, dihydrazides of dicarboxylic acids containing 2 to 10 carbon atoms, particularly adipic acid dihydrazide, isophthalic acid dihydrazide, and succinic acid hydrazide are particularly preferred.
[0086]
These hydrazine derivatives (B) are preferably 0.25 to 2 equivalents, more preferably 0.3 to 1.5 equivalents, and still more preferably 0.4 to 1.2 equivalents per equivalent of carbonyl group in the fine particles (A) of the acrylic copolymer. An equivalent range is desirable. If the amount of carbodihydrazide used is not less than the lower limit, the acrylic copolymer is sufficiently crosslinked, and the resulting foamed layer has excellent friction fastness, rebound resilience, sound absorption, etc. Moreover, if it is below this upper limit, since the adhesiveness to the fiber base material of a foam layer is not impaired, it is preferable.
[0087]
Thus, the acrylic copolymer used in the present invention can give a strong cross-linked coating by the hydrazine residue of the hydrazine derivative (B) undergoing a cross-linking reaction with the carbonyl group of the copolymer, only by substantially drying. In addition to providing a film having strong adhesion to a fiber substrate such as cloth, paper, fiber, etc., it also improves sound absorption, flexibility, rebound resilience, friction fastness, water resistance, and the like.
[0088]
In general, the degree of crosslinking of a copolymer can be determined by measuring the dynamic viscoelastic properties of a film formed from the copolymer.
[0089]
FIG. 1 is a conceptual diagram showing dynamic viscoelastic properties of a film formed from a copolymer. Elastic modulus (eg N / m) on the vertical axis²) When the temperature (° C.) is taken on the horizontal axis, the resin generally maintains a high elastic modulus in a glassy region exhibiting a glass state in the cryogenic temperature range, but the long chain molecules gradually gradually increase as the temperature rises. It begins to move, and when it exceeds a certain temperature, its elastic modulus decreases rapidly. The temperature at this time is the glass transition point (Tg) of the copolymer, and this region where the elastic modulus rapidly decreases as the temperature rises is the transition region. When the temperature further rises, it again reaches a terraced region where the rate of decrease in elastic modulus is small, ie, a rubbery region. In this region, it is said that the elastic modulus is maintained by the entanglement (physical) of the molecular chains of the resin and the degree of crosslinking of the molecules (chemical). A copolymer in which the rubber-like region extends to the high temperature side has a high high temperature elastic modulus. When the temperature is further increased, the copolymer rapidly decreases its elastic modulus and reaches the flow region. In this region, the molecular chain of the copolymer performs free thermal motion (Brownian motion).
[0090]
In this specification, the intersections of the tangents of the temperature-elastic modulus curve in the glassy region, transition region, rubbery region, and flow region are u, v, and w, respectively, and the temperature corresponding to each of these intersections is Tu, When Tv and Tw, the temperature Tu coincides with the glass transition point Tg, the region lower than this temperature is a glassy region, the transition region between temperatures Tu and Tv, and the temperature Tv and Tw. The rubbery region and temperature Tw are assumed to coincide with the softening point Tm, and the region higher than this temperature is defined as the flow region.
[0091]
FIG. 2 shows a cross-linked film (x) formed by a blend of a carbonyl group and a hydrazine derivative (B) in fine particles (A) of the acrylic copolymer in the present invention, and a conventional acrylic copolymer. It is a conceptual diagram which compares the dynamic viscoelastic property of a non-crosslinked or low crosslinked film (y). In FIG. 2, the curve (x) representing the dynamic viscoelastic properties of the crosslinked film according to the present invention has an upper limit of the rubbery region extending to a high temperature region, for example, a temperature region of 160 ° C. or higher. On the other hand, the curve (y) representing the dynamic viscoelastic properties of the conventional non-crosslinked or low-crosslinked film, the upper limit of the rubbery region extends only to a lower temperature, for example, a temperature range of 140 ° C. or less, If the temperature is higher than that, it will shift to the fluidized zone. This indicates that the aqueous acrylic copolymer composition of the present invention has excellent elasticity even at high temperatures.
[0092]
In addition, in this specification, the dynamic viscoelastic property of a film is the value measured by the following.
[0093]
Measurement of dynamic viscoelastic properties:
The dynamic viscoelastic properties of the film were measured using a fully automatic low drive viscoelasticity measuring device [Leo Vibron DDV-III-EP; manufactured by Toyo Baldwin Co., Ltd.]. The measuring method was in accordance with the method described in the instruction manual V-1180 of the measuring instrument. The method is outlined below.
[0094]
An emulsion with a thickness of 1 to 2 mm is poured into a silicone mold, dried at room temperature for 3 days, and then further dried in a dryer at 40 ° C. for 8 hours. The resulting dried film was used as a sample. . The measurement was performed under the following conditions.
Sample size: Tensile test 10 x 50mm Thickness 1-2mm
For shear test 10 × 20 mm, thickness 3 to 5 mm; however, a specimen for shear test was prepared by stacking three obtained dry films.
[0095]
Measurement temperature range: Tensile test -80 ℃ to about 10 ℃
Shear test Approx. 10 to 200 ° C
Temperature increase rate: 3 ° C / min
Measurement frequency: 11 Hz
[0096]
The aqueous acrylic copolymer composition for forming a foamed layer of the present invention comprises the foaming agent (C) and the foam stabilizer (D) together with the acrylic copolymer fine particles (A) and the hydrazine derivative (B). It contains.
[0097]
The foaming agent (C) is not particularly limited, and any foaming agent that helps to form air bubbles by mechanical stirring or the like can be used. It is customary to select and use as appropriate. Among these surfactants, from the viewpoint of not generating “environmental hormones” as described above, it is preferable to use the nonionic surfactants and anionic surfactants that do not contain an alkylphenyl group. (3) polyoxyethylene alkyl or alkenyl ether sulfates, alkylaryl sulfonates, alkyl (or alkenyl) sulfates and polyoxyethylene alkyl (or alkenyl) ethers represented by the general formula (4) It is more preferable to use a sulfate ester salt, an alkyl (or alkenyl) sulfate ester salt having 8 to 20 carbon atoms is more preferable, and sodium lauryl sulfate is particularly preferable.
[0098]
The amount of the foaming agent (C) used is not particularly limited, and the use of the composition of the present invention, the thickness of the foamed layer formed, and the aqueous dispersion of the acrylic copolymer fine particles (A). Although an appropriate amount can be used depending on the characteristic value (for example, viscosity, solid content, etc.), for example, 0.5 to 5 parts by weight, preferably 1 to 3 parts by weight is used with respect to 100 parts by weight of the fine particles (A). More preferably.
[0099]
The bubble stabilizer (D) that can be used in the present invention is not particularly limited, and any one can be used as long as it is effective to keep the formed bubbles stable, for example, agar, carrageenan, pectin. Natural gums such as gum arabic, locust bean gum, gua gum, corn starch, gelatin, casein; synthetic glues such as sodium alginate, carboxymethylcellulose, methylcellulose, hydroxyethylcellulose; salts of higher fatty acids, etc. Of these, salts of higher fatty acids, for example, ammonium salts of fatty acids having 12 to 20 carbon atoms are preferred, and use of fatty acid ammonium salts mainly composed of stearic acid is particularly preferred.
[0100]
The amount of the foam stabilizer (D) used is not particularly limited, and the use of the composition of the present invention, the thickness of the foamed layer formed, and the aqueous dispersion of the acrylic copolymer fine particles (A). An appropriate amount can be used depending on the characteristic value of the liquid (for example, viscosity, solid content, etc.), the type and amount of the foaming agent (C), for example, 1 for 100 parts by weight of the fine particles (A). It is preferable to use ˜10 parts by weight, and it is more preferable to use 2 to 7 parts by weight.
[0101]
The aqueous acrylic copolymer composition for forming a foamed layer of the present invention can contain an inorganic filler, if necessary. Examples of such inorganic fillers include inorganic solid powders that are substantially insoluble or hardly soluble in water, such as calcium carbonate, silica, alumina, kaolin, clay, talc, diatomaceous earth, mica, aluminum hydroxide, glass powder, sulfuric acid. Examples include barium and magnesium carbonate.
[0102]
The compounding amount of these inorganic fillers can be varied in a wide range depending on the type and use of the processed product in which the foamed layer is provided by the composition of the present invention. The amount of (the total of the inorganic filler and the following inorganic coloring pigment, etc.) is preferably 50% by weight or less, more preferably 30% by weight or less based on the weight of the foamed layer. When it is provided in the required option mat in the automobile interior, the blending amount of the inorganic filler is preferably 20% by weight or less.
[0103]
Various kinds of additives can be further blended in the acrylic copolymer aqueous composition for forming a foamed layer of the present invention, if necessary.
[0104]
These additives include, for example, organic or inorganic color pigments such as titanium oxide, carbon black, petals, Hansa yellow, benzidine yellow, phthalocyanine blue, quinacridone red; and inorganic dispersions such as sodium hexametaphosphate and sodium tripolyphosphate Dispersants such as organic dispersants such as agents, for example, Nop Cospers 44C (trade name) [polycarboxylic acid type, manufactured by San Nopco Co., Ltd.]; for example, polyvinyl alcohol, cellulose derivatives, polycarboxylic acid type resins, surfactant type Thickeners and viscosity improvers such as silicone-based antifoaming agents; organic solvents such as terpene ethylene glycol, butyl cellosolve, butyl carbitol, butyl carbitol acetate; anti-aging agents; Agent; ultraviolet absorber; antistatic agent; It can be mentioned.
[0105]
The aqueous acrylic copolymer composition for forming a foamed layer of the present invention is not particularly limited, but the solid content is generally about 40 to 80% by weight, preferably about 45 to 75% by weight, particularly preferably about In the range of 50 to 70% by weight; pH, generally 7 to 11, preferably 8 to 10; viscosity, generally about 3,000 to 100,000 mPa · s, preferably about 5,000 to 50,000 mPa · s (type B rotational viscosity) Total, 25 ° C., 20 rpm, and so on).
[0106]
Further, when using the composition of the present invention, the above-mentioned specific acrylic copolymer fine particles (A), hydrazine derivative (B), foaming agent (C) and cell stabilizer (D), and further if necessary Then, after blending the above-mentioned various additives and mixing them uniformly, using an appropriate mechanical stirrer, for example, a stirrer having a stirring blade such as a saddle type, turbine type, propeller type, etc., if necessary, nitrogen or air The composition is foamed by stirring while blowing. The degree of foaming (foaming ratio) is not particularly limited and can be varied in a wide range depending on the use of the processed product provided with the foamed layer, but based on the volume of the composition before foaming, In general, it is 1.5 to 6 times, preferably about 2 to 5 times. However, when the foamed layer is provided in an optional mat in an automobile room that requires sound absorption, it should be in the range of 2 to 4 times. Is preferred.
[0107]
This foamed composition is then applied to one or both surfaces of the fiber substrate by an appropriate coating means such as a knife coater or a roll coater, for example, a hot air drying method, a hot cylinder method, an infrared irradiation method. A foamed layer having open cells can be formed by drying using a conventional drying method such as. The density of the obtained foam layer can also be appropriately selected according to the use of the processed product on which the foam layer is provided, and is generally 0.2 to 0.7 g / cm.^ThreeIt is good to be in the range. When the foam layer is installed in an optional mat in an automobile room where sound absorption is required, 0.3 to 0.6 g / cm^ThreeIt is especially preferable to set the range.
[0108]
In the present specification, the density of the foamed layer is a value measured as follows.
[0109]
Measurement of foam layer density:
Teflon (registered trademark) petri dish with a volume of 100 mL that has been measured in advance (w₀: Unit g) was filled with a foam composition so as to have a thickness of about 5 mm, dried at 80 ° C. for 3 hours, allowed to cool to room temperature and measured for weight (w₁: Unit g). For the purpose of sealing, a wax melted at about 90 ° C. (melting point: about 60 ° C.) was applied to the surface of the obtained foam layer using a brush, allowed to cool to room temperature, and the weight was measured (w₂: Unit g). Next, the petri dish containing this foamed layer was filled with water until it was full and weighed (w_Three: Unit g). Using these measured values, the density of the foamed layer was determined according to the following formula.
[0110]
[Expression 1]

However, the volume of 1g of water is 1cm.^ThreeAnd Moreover, since the thickness of the wax used as the seal is around 10 μm, it is considered to be negligible compared to the thickness of the foam (about 5 mm).
[0111]
Appropriate fiber substrates to be applied include natural fibers such as cotton, hemp, and hair; regenerated fibers such as rayon; semi-synthetic fibers such as acetate fiber and promix fiber; and polyester fibers, polyamide fibers, and vinylon. Examples thereof include woven fabrics, knitted fabrics, nonwoven fabrics, felts, and papers made of synthetic fibers such as fibers.
[0112]
Next, an option mat in an automobile interior provided with a foam layer using the aqueous acrylic copolymer composition for foam layer formation of the present invention will be described.
[0113]
FIG. 3 is a conceptual view of an option mat produced using the aqueous acrylic copolymer composition for forming a foam layer of the present invention. In this optional mat (10), the foamed layer (1) formed by the composition of the present invention is located between the fiber substrate (2) in which the pile (3) is implanted and the backing nonwoven fabric (4). An anti-slip layer (5) is formed on the back surface (the surface opposite to the surface in contact with the foamed layer (1)) of the backing nonwoven fabric (4). The pile (3), the fiber substrate (2), and the backing nonwoven fabric (4) are made of synthetic fibers such as polyester. The foamed layer (1) is formed by, for example, adding an hydrazine derivative such as adipic acid dihydrazide to an aqueous dispersion of acrylic copolymer fine particles having a glass transition point (Tg) of about −20 ° C. containing a carbonyl group and a carboxyl group in the molecule 0.5 equivalents of 1 equivalent of carbonyl group in the fine particles, about 1 part by weight of a foaming agent such as sodium lauryl sulfate per 100 parts by weight of the fine particles, and stabilization of bubbles such as ammonium salts of higher fatty acids mainly composed of stearic acid About 8.5 parts by weight of the agent per 100 parts by weight of the fine particles, and after blending an appropriate amount of the polycarboxylic acid thickener, 25% aqueous ammonia is added to increase the viscosity to 5000-20000 mPa · s, Next, this is foamed up to about 3 times based on the volume of the composition before foaming by mechanical stirring, and directly applied to the fiber substrate (2) by a coating means such as a knife coater. 200 2000 g / m²Applying to a certain amount, immediately overlaying the backing nonwoven fabric (4), and then drying with a hot air drier etc. at a temperature of about 80 ° C. in the initial stage of drying and about 150 ° C. in the final step It is formed. By forming the foamed layer (1) by such a method, it is possible to prevent the pile (3) from coming off from the fiber base material (2) and to remove the foamed layer (1) from a separate adhesive. Without this, the fiber base material (2) and the backing nonwoven fabric (4) can be firmly bonded.
[0114]
The obtained foam layer (1) preferably absorbs vibration and noise from the floor of the automobile as much as possible.For example, the sound absorption coefficient at a frequency of 4000 Hz by the normal incident sound absorption coefficient method is 0.6 or more, particularly It is preferably 0.8 or more.
[0115]
The anti-slip layer (5) is provided to prevent the optional mat (10) obtained from being slipped and moved easily by an external force such as a human foot when used in an automobile. The material is not necessarily limited as long as the material is suitable for such a function. For example, the composition used for the foam layer (1) may be foamed or non-foamed, or the composition. Further, an appropriate inorganic filler added thereto is foamed or non-foamed and applied to the back surface of the backing nonwoven fabric (4) and dried. The coating amount when the non-slip layer (5) is dried is 10 to 100 g / m.²It is preferable that the amount is about.
[0116]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples. In addition, the test method and evaluation method in a present Example are as follows.
[0117]
1. Creating test sheets
1-1. Test sheet (1)
As a fiber substrate, basis weight is about 310 g / m²Using a polyester spunbonded nonwoven fabric having a thickness of about 5 mm and using a predetermined doctor blade on one surface thereof, a foamed acrylic copolymer aqueous composition for foaming layer formation was foamed at a predetermined magnification. Approx. 600 g / m²The slit of the doctor blade was adjusted and coated so as to become a test sheet (1) after preliminary drying at 80 ° C. for 30 minutes and further drying at 140 ° C. for 10 minutes in a hot air circulating dryer.
[0118]
1-2. Test sheet (2)
After applying the foamed acrylic copolymer aqueous composition for foaming layer formation in the same manner as the test sheet (1), when wet, the same non-woven fabric as the fiber base material is bonded to the coated surface. 5.3 kg / m²The test sheet (2) was prepared by preliminarily drying at 80 ° C. for 30 minutes and further drying at 140 ° C. for 10 minutes in a hot air circulating dryer.
[0119]
2. Friction fastness of foam layer
2-1. Normal fastness
The test sheet (1) prepared in the previous section (1-1) was left in a room at 23 ° C. and 60% RH for 1 hour or longer, and then measured using the Gakushin type tester under the following conditions.
Friction element 45R Kanakin coating (dry)
200g load
300 times
The evaluation criteria are as follows:
○: Almost no damage to the surface layer.
Δ: Some damage to the surface layer.
X: The surface layer is significantly damaged.
[0120]
2-2. Water fastness
The test sheet (1) prepared in the previous section (1-1) was immersed in water for 10 minutes, and then measured using the Gakushin type tester under the following conditions.
Friction element 45R Canakin coating (wet thoroughly with water)
200g load
100 times
The evaluation criteria are as follows:
○… Almost no damage to the surface layer.
Δ: Some damage to the surface layer.
×… The surface layer is significantly damaged.
[0121]
3. Evaluation of sound absorption
For the test sheet (2) created in the previous paragraph (1-2), measure the normal incident sound absorption coefficient at a frequency of 800 to 5000 Hz by a method based on JIS A 1405-1998, and calculate the sound absorption coefficient value at a frequency of 4000 Hz. It was a guideline for sex.
[0122]
The sound absorption coefficient at a frequency of 4000 Hz generally needs to be 0.3 or more, preferably 0.6 or more, and more preferably 0.8 or more.
[0123]
Four. Nonwoven fabric substrate adhesion
The test sheet (2) prepared in the previous section (1-2) was allowed to stand for 3 hours or more under a constant temperature and humidity condition of 23 ° C. and 65% RH, and then the normal peel strength was measured under the same condition. Tensilon UYM-4100 (manufactured by Toyo Baldwin Co., Ltd.) was used for measurement, the measurement specimen was 25 mm wide, the grip interval was 100 mm, and the tensile speed was 300 mm / min.
[0124]
In general, the adhesive strength to the nonwoven fabric substrate is preferably 600 g / 25 mm or more, more preferably 750 g / 25 mm or more, and particularly preferably 900 g / 25 mm or more.
[0125]
Five. Feel
The texture of the test sheet (2) prepared in the previous section (1-2) was evaluated by touch. The evaluation criteria are as follows.
Y: Flexible
Δ: Slightly hard
×: Hard
[0126]
[Production of aqueous dispersion of acrylic copolymer fine particles]
Production Example 1
In a reactor equipped with a thermometer, a stirrer, a nitrogen introduction tube and a reflux condenser, 30 parts by weight of ion-exchanged water was charged, and the internal temperature was raised to 60 ° C. On the other hand, in a separate container, 20 parts by weight of ion-exchanged water and a surfactant for emulsion polymerization (hereinafter sometimes simply referred to as an emulsifier) “DKS NL-180” [polyoxyethylene (n = 22) lauryl ether Type nonionic surfactant (active ingredient concentration 100% by weight); Daiichi Kogyo Seiyaku Co., Ltd.] (NL180) 3 parts by weight and “Hytenol 08E” [polyoxyethylene (n = 8) oleyl ether sulfate type Anionic surfactant (active ingredient concentration about 95% by weight); Daiichi Kogyo Seiyaku Co., Ltd.] (H08E) 0.5 part by weight (active ingredient amount about 0.48 part by weight) was stirred and dissolved to create an aqueous emulsifier solution. Then, 1 part by weight of diacetone acrylamide (DAAM) as a carbonyl-containing monomer (c) and 1 part by weight of itaconic acid (IA) as an unsaturated carboxylic acid (d) were added thereto and dissolved by stirring. Next, in this aqueous solution, 40.3 parts by weight of butyl acrylate (BA) and 47.7 parts by weight of ethyl acrylate (EA) as main monomers (a) and 10 parts by weight of acrylonitrile (AN) as vinyl cyanide monomer (b) A monomer mixture comprising the above was added and stirred to obtain a monomer emulsion.
[0127]
The reactor contents were heated with stirring under a nitrogen stream, and when the water temperature in the reactor reached 60 ° C., a 4 wt% ammonium persulfate (APS) aqueous solution and 4 wt% were used as a polymerization initiator and a reducing agent. After adding 1.67 parts by weight of each of the 1% sodium metabisulfite (SMBS) aqueous solution, the monomer emulsified liquid, 4% by weight potassium persulfate aqueous solution, and 4% by weight sodium metabisulfite each having 8.33 parts by weight were sequentially added. The polymerization reaction was carried out at about 4 hours for about 4 hours. After completion of the polymerization reaction, stirring is continued for about 1 hour at the same temperature, followed by cooling, and then adjusting the pH to 6-8 with 25 wt% aqueous ammonia to prepare an aqueous solution of acrylic copolymer fine particles containing carbonyl groups and carboxyl groups. A dispersion was obtained. The obtained aqueous dispersion had a solid content of 59.6% by weight, pH 7.1, a viscosity of 150 mPa · s (25 ° C., BH type rotational viscometer 20 rpm; the same applies hereinafter unless otherwise indicated), and the average particle size of dispersed particles 290 nm and the Tg of the acrylic copolymer was -20 ° C.
[0128]
Production Example 2
In Production Example 1, 5% by weight of the aqueous emulsifier solution was charged into the reactor, DAAM and IA were dissolved in the remaining 95% by weight of the emulsifier aqueous solution, and this aqueous solution was used in the same manner as in Production Example 1. An aqueous dispersion of acrylic copolymer fine particles was obtained in the same manner as in Production Example 1 except that an emulsion was prepared. Table 1 shows the composition of the monomers and emulsifiers used, and the solid content, pH, viscosity, average particle diameter of the dispersed particles, and Tg of the acrylic copolymer obtained in the aqueous dispersion of the obtained acrylic copolymer. Are shown in Table 2.
[0129]
Production Examples 3-7
In Production Example 1, the amount of DAAM used as the carbonyl-containing monomer (c) is changed or not used, and the amounts of BA and EA used in the main monomer (a) are adjusted as necessary. Acrylic copolymer having almost the same Tg as in Production Example 1 except that the functional comonomer glycidyl methacrylate (GMA) or triallyl cyanurate (TAC) is used in combination as the comonomer (e). An aqueous dispersion of coalesced fine particles was obtained. Table 1 shows the composition of the monomers and emulsifiers used, and Table 2 shows the solid content, pH, viscosity, average particle diameter of the dispersed particles, and Tg of the acrylic copolymer obtained. .
[0130]
Production Examples 8-12
In Production Example 1, the type and / or use amount of the unsaturated carboxylic acid (d) is changed, or this is not used, and the BA and EA use amounts of the main monomer (a) are adjusted as necessary and An aqueous dispersion of acrylic copolymer fine particles having substantially the same Tg was obtained in the same manner as in Production Example 1 except that the amount of vinyl cyanide monomer used was adjusted. Table 1 shows the composition of the monomers and emulsifiers used, and Table 2 shows the solid content, pH, viscosity, average particle diameter of the dispersed particles, and Tg of the acrylic copolymer obtained. . However, when acrylic acid (AA) or methacrylic acid (MAA) is used as the unsaturated carboxylic acid (d), it is dissolved in water together with the carbonyl-containing monomer (c) and the emulsifier when preparing the monomer emulsion. Instead of making an emulsifier aqueous solution, a monomer mixture together with the main monomer (a) and the vinyl cyanide monomer (b) was added to the emulsifier aqueous solution and stirred to obtain a monomer emulsion.
[0131]
Of these, the aqueous dispersion of acrylic copolymer fine particles of Production Example 8 in which the unsaturated carboxylic acid monomer (b) is not copolymerized has many aggregates and is difficult to filter. The mechanical stability was so poor that the emulsion could be easily broken just by rubbing. On the other hand, the aqueous dispersion of the acrylic copolymer fine particles of Production Example 12 in which MAA was slightly copolymerized was gelled in a purine state after about 1 week at room temperature. Furthermore, the aqueous dispersion of the acrylic copolymer fine particles of Production Example 7 in which DAAM was somewhat more copolymerized had more agglomerates and took time to filter.
[0132]
Production Examples 13-21
In Production Example 1, as shown in Table 1, the type and / or amount of the main monomer (a) is changed, the amount of the vinyl cyanide monomer (b) is changed, and if necessary, An aqueous dispersion of an acrylic copolymer having a different Tg was obtained in the same manner as in Production Example 1 except that the body (e) was used, the type of emulsifier was changed, and the amount of deionized water in the aqueous emulsifier solution was changed. . Table 1 shows the composition of the monomers and emulsifiers used, and the solid content, pH, viscosity, average particle diameter of the dispersed particles, and Tg of the acrylic copolymer obtained in the aqueous dispersion of the obtained acrylic copolymer. Are shown in Table 2.
[0133]
The abbreviations of monomers and emulsifiers used in Table 1 are as follows.
EHA: 2-ethylhexyl acrylate
BA: Butyl acrylate
EA: Ethyl acrylate
MMA: Methyl methacrylate
AN: Acrylonitrile
DAAM: Diacetone acrylamide
AA: Acrylic acid
MAA: Methacrylic acid
IA: Itaconic acid
St: Styrene
TAC: triallyl cyanurate
[0134]
NL180: “DKS NL180” (trade name); polyoxyethylene (n = 22) lauryl ether type nonionic surfactant (active ingredient concentration: 100% by weight); manufactured by Daiichi Kogyo Seiyaku Co., Ltd.
NL250: “DKS NL250” (trade name); polyoxyethylene (n = 25) lauryl ether type nonionic surfactant (active ingredient concentration: 100% by weight); manufactured by Daiichi Kogyo Seiyaku Co., Ltd.
NL450: “DKS NL450” (trade name); polyoxyethylene (n = 50) lauryl ether type nonionic surfactant (active ingredient concentration: 100% by weight); manufactured by Daiichi Kogyo Seiyaku Co., Ltd.
Y500: “Monogen Y-500” (trade name); Lauryl sulfate ester type anionic surfactant (active ingredient concentration: 100% by weight); manufactured by Daiichi Kogyo Seiyaku Co., Ltd.
No.6: “Neopelex No.6” (trade name); Dodecylbenzenesulfonate type anionic surfactant (active ingredient concentration 60% by weight); manufactured by Kao Corporation
H-08E: “Hytenol-08E” (trade name); polyoxyethylene (n = 8) oleyl ether sulfate ester type anionic surfactant (active ingredient concentration 95% by weight); Daiichi Kogyo Seiyaku Co., Ltd. Made
[0135]
[Table 1]

[0136]
[Table 2]

[0137]
[Preparation of Aqueous Copolymer Aqueous Composition for Foam Layer Formation]
Example 1
175 parts by weight of aqueous dispersion of acrylic copolymer fine particles of Production Example 1 [about 104.3 parts by weight of solid content; about 100 parts by weight of copolymer; about 0.00592 equivalent parts of carbonyl group (note that “equivalent part” means , 100 parts by weight is expressed as the equivalent number when read as 100 g)] and 0.257 parts by weight of adipic acid dihydrazide (ADH) as hydrazine derivative (B) (about 0.00299 equivalents; carbonyl group 1 of copolymer) 10.5 parts by weight of 30% aqueous solution of “Monogen Y-500” (Y500) as the foaming agent (C) (approx. 3.5 parts by weight of active ingredient) As a foam stabilizer (D), “Nopco DC-100-A” [trade name: ammonium stearate; active ingredient concentration 33% by weight; manufactured by San Nopco Co., Ltd.] (DC100) 8.7 parts by weight (active ingredient amount of about 2.9% by weight) Part) was added and mixed uniformly using a disper-type stirrer. Next, "Nicazole VT-253A" as a thickening agent (trade name; polycarboxylic acid resin aqueous dispersion (active ingredient concentration: about 27% by weight); manufactured by Nippon Carbide Industries, Ltd.) 4.7 parts by weight (active ingredient amount: about 1.3 Part by weight) and the pH was adjusted to about 8.5 with 25% aqueous ammonia to obtain an aqueous acrylic copolymer composition for foaming layer formation having a solid content of 55.8% by weight and a viscosity of about 10,000 mPa · s.
[0138]
Separately, a composition in which only 0.26 parts by weight of ADH was added to 175 parts by weight of the acrylic copolymer fine particle aqueous dispersion of Production Example 1, and the dynamic viscoelastic properties of the crosslinked film were measured according to the above. It was confirmed that a crosslinked film having excellent elasticity in which the upper limit of the rubbery region reaches 185 ° C. was formed.
[0139]
Examples 2 to 5 and Comparative Example 1
In Example 1, the amount of ADH used was changed or not used, or instead of using 0.5 equivalent ratio of ADH, 0.5 equivalent ratio of carbonic dihydrazide (CDH) was used, and if necessary, foaming agent (C), bubbles A foamed layer-forming acrylic copolymer aqueous composition was obtained in substantially the same manner as in Example 1 except that the amount of the stabilizer (D) and / or the thickener was adjusted. In the same manner as in Example 1, the dynamic viscoelastic properties of the crosslinked film were measured. Table 3 shows the composition of the obtained composition, and Table 4 shows the characteristic values of the composition and the dynamic viscoelastic properties of the crosslinked film.
[0140]
Examples 6-22 and Comparative Examples 2-4
In Example 1, instead of using the acrylic copolymer fine particle aqueous dispersion of Production Example 1, the acrylic copolymer fine particle aqueous dispersion of Production Examples 2 to 21 was used, and each of the acrylic copolymer fine particles was used. The amount of ADH used was adjusted so that the equivalent ratio of ADH to 0.5 equivalent of carbonyl group in the mixture was 0.5 (however, in Production Example 3 with carbonyl group equivalent of 0, the same amount as in Example 1). An acrylic copolymer aqueous composition for forming a foamed layer was obtained in substantially the same manner as in Example 1 except that the amount of the foaming agent (C), the foam stabilizer (D) and / or the thickener was adjusted. In the same manner as in Example 1, the dynamic viscoelastic properties of the crosslinked film were measured. Table 3 shows the composition of the obtained composition, and Table 4 shows the characteristic values of the composition and the dynamic viscoelastic properties of the crosslinked film.
[0141]
Examples 23-25
In Example 1, aluminum hydroxide (BW-703; trade name; manufactured by Nippon Light Metal Co., Ltd.) or heavy calcium carbonate (R heavy coal; trade name; manufactured by Maruo Calcium Co., Ltd.) which is an inorganic filler as an inorganic compound. ] In the same manner as in Example 1 except that the amounts of the foaming agent (C), the foam stabilizer (D) and / or the thickener are adjusted as necessary. An acrylic copolymer aqueous composition was obtained. Table 3 shows the composition of the obtained composition, and Table 4 shows the characteristic values of the composition.
[0142]
The abbreviations of hydrazine derivatives and inorganic compounds used in Table 3 are as follows.
ADH: Adipic acid dihydrazide
CDH: Carbonic dihydrazide
BW703: “BW-703” (trade name); aluminum hydroxide; manufactured by Nippon Light Metal Co., Ltd.
R heavy coal: “R heavy coal” (trade name); heavy calcium carbonate; manufactured by Maruo Calcium Co., Ltd.
[0143]
[Table 3]

[0144]
[Table 4]

[0145]
Example 31
In a polyethylene beaker having a capacity of about 500 mL, 100 g of the aqueous acrylic copolymer composition for foaming layer formation obtained in Example 1 is weighed and stirred at a high speed using a disper type stirrer having a diameter of about 3 cm. Foaming was performed until the volume reached about 3 times while mixing bubbles. The resulting foamed composition had a viscosity of about 21000 mPa · s. Using this foamed composition, the density of the foamed layer was measured according to the above method, and test sheets (1) and (2) were prepared according to the methods of (1-1) and (1-2), The above various tests were performed using these test sheets (1) and (2). The obtained foam layer was confirmed to be formed by open cells by visual observation with a magnifier of the cross section, and the density was about 0.34 g / cm.²Met. In addition, Table 5 shows the sound absorption, base material adhesion, and texture of this test sheet.
[0146]
Examples 32-33
In Example 31, a foamed composition was obtained in the same manner as in Example 31 except that the size of the container to be used was changed as necessary and the expansion ratio was about 1.5 times or about 6 times. The various tests described above were performed using the obtained foamed composition. Table 5 shows the expansion ratio and viscosity of the foamed composition, and the foam layer density and various physical properties of the obtained test sheet.
[0147]
Examples 34 to 57 and Comparative Examples 31 to 34
In Example 31, instead of using the aqueous acrylic copolymer composition for forming a foam layer of Example 1, the aqueous acrylic copolymer composition for forming a foam layer of Examples 2 to 25 and Comparative Examples 1 to 4 was used. A foamed composition was obtained in the same manner as in Example 31 except that any of the above was used. The various tests described above were performed using the obtained foamed composition. Table 5 shows the type of the acrylic copolymer aqueous composition for forming a foam layer used, the viscosity of the obtained foam composition, the foam layer density and various physical properties of the obtained test sheet.
[0148]
The foamed composition of Comparative Example 31 contained a considerable amount of agglomerates therein, and when the test sheet was applied to the fiber base material, noisy streaks occurred and a smooth foamed layer surface could not be obtained.
[0149]
[Table 5]

[0150]
【The invention's effect】
The aqueous acrylic copolymer composition for forming a foamed layer according to the present invention contains acrylic copolymer fine particles (A) containing a carbonyl group and a carboxyl group and having a specific glass transition point (Tg) in the molecule. It comprises a hydrazine derivative (B) having a plurality of hydrazide residues, a foaming agent (C) and a foam stabilizer (D).
[0151]
By configuring as described above, the acrylic copolymer aqueous composition for forming a foamed layer of the present invention has a fiber base such as a woven fabric, a knitted fabric, a nonwoven fabric, a felt, and a paper made of natural fibers, regenerated fibers, synthetic fibers and the like. When a foam layer is formed on a material, it can be crosslinked at a relatively low temperature such as the drying temperature without causing inconvenience such as deformation of the fiber base material by heat, and is also a health harmful substance such as formaldehyde And the resulting product including the foamed layer is also robust and substantially free of harmful substances such as formaldehyde. In particular, when the composition of the present invention is used to form a foam layer in a so-called “option mat” that is partially placed on an automobile floor carpet, the foam layer has a high soundproofing effect, and the fiber. When a pile or the like is planted on the base material, it can also function as a retainer, and when it has a protective layer on the back surface of the foamed layer, it can also function as an adhesive for the protective layer.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram showing dynamic viscoelastic properties of a film formed from a copolymer.
FIG. 2 shows a cross-linked film (x) formed from a blend of acrylic copolymer fine particles (A) and a hydrazine derivative (B) of the present invention, and a conventional acrylic copolymer non-coated. It is a conceptual diagram which compares the dynamic viscoelastic property of a bridge | crosslinking or a low bridge | crosslinking film (y).
FIG. 3 is a conceptual diagram of an option mat produced using the aqueous acrylic copolymer composition for forming a foam layer of the present invention.
[Explanation of symbols]
u: intersection of curves representing a glassy region and a transition region.
v: intersection of curves representing transition and rubbery regions.
w: intersection of curves representing rubbery region and flow region.
Tu: defined as the temperature at the intersection of the curves representing the glassy region and the transition region, equal to the glass transition point (Tg).
Tv: temperature at the intersection of curves representing transition and rubbery regions.
Tw: Defined as the temperature at the intersection of curves representing the rubbery region and the flow region, equal to the softening point (Tm).
x: a crosslinked film formed from a blend of the acrylic copolymer fine particles (A) of the present invention and a hydrazine derivative (B).
y: A conventional non-crosslinked or low-crosslinked film of an acrylic copolymer.
1: Foam layer
2: Fiber substrate (mat)
3: Pile
4: Backed nonwoven fabric
5: Anti-slip layer
10: Option mat

Claims (26)

(A) to (D) below
(A) Acrylic copolymer fine particles having a glass transition point (Tg) of −10 ° C. or less containing a carbonyl group and a carboxyl group in the molecule,
(B) a hydrazine derivative having a plurality of hydrazide residues in the molecule,
(C) foaming agent, and
(D) Cell stabilizer,
An aqueous acrylic copolymer composition for forming a foamed layer, comprising: The aqueous acrylic copolymer composition according to claim 1, wherein the acrylic copolymer is a copolymer derived from an acrylic ester or a monomer containing 50 wt% or more of an acrylic ester and a methacrylic ester. Acrylic copolymer fine particles (A), the following monomers (a) ~ (e),
(a) 50-95.4% by weight of a monomer represented by the following general formula (1),
H ₂ C = CR ¹ -COOR ² (1)
(In the formula, R ¹ represents hydrogen or a methyl group, and R ² represents a linear or branched alkyl group having 1 to 10 carbon atoms)
(b) 4 to 23% by weight of vinyl cyanide monomer,
(c) a carbonyl group-containing monomer 0.1 to 5% by weight,
(d) 0.5 to 10% by weight of an α, β-unsaturated mono- or di-carboxylic acid having 3 to 5 carbon atoms,
(e) 0 to 20% by weight of a comonomer other than the monomers (a) to (d), which is copolymerizable with the monomers (a) to (d).
[However, the total of the above (a) to (e) is 100% by weight]
The aqueous acrylic copolymer composition according to claim 1, which is formed of an acrylic copolymer obtained by emulsion copolymerization. The aqueous acrylic copolymer composition according to claim 3, wherein the monomer (a) is one or more monomers selected from the group consisting of butyl acrylate, ethyl acrylate, and methyl methacrylate. The aqueous acrylic copolymer composition according to claim 3, wherein the monomer (c) is diacetone (meth) acrylamide. The acrylic copolymer aqueous composition according to claim 1, wherein the average particle diameter of the acrylic copolymer fine particles (A) is in the range of 200 to 500 nm. Emulsion copolymerization is carried out in the presence of a surfactant that is substantially free of alkylphenyl surfactants and contains aliphatic alcohol polyoxyethylene ether type nonionic surfactants having 10 to 20 carbon atoms as a main component. The aqueous acrylic copolymer composition according to claim 3. The aqueous acrylic copolymer composition according to claim 7, further comprising an anionic surfactant other than alkylphenyl as a surfactant. The acrylic copolymer aqueous solution according to claim 7, wherein the total amount of the surfactant used is in the range of 1 to 10 parts by weight as an active ingredient with respect to 100 parts by weight of the acrylic copolymer fine particles (A). Composition. The hydrazine derivative (B) is 100 parts by weight of water. The aqueous acrylic copolymer composition according to claim 1, which dissolves 1 part by weight or more. The aqueous acrylic copolymer composition according to claim 1 or 10, wherein the hydrazine derivative (B) is an organic compound containing 2 to 10 carbon atoms. 12. The acrylic copolymer aqueous composition according to claim 1, wherein the hydrazine derivative (B) is a dicarboxylic acid dihydrazide. The aqueous acrylic copolymer composition according to any one of claims 1 and 10 to 12, wherein the hydrazine derivative (B) is selected from adipic acid dihydrazide, isophthalic acid dihydrazide, and succinic acid hydrazide. The acrylic copolymer aqueous composition according to claim 1, wherein the hydrazine derivative (B) is contained in an amount of 0.25 to 2 equivalents relative to 1 equivalent of the carbonyl group of the acrylic copolymer. The upper limit of the rubber-like region in the dynamic viscoelastic curve of a 3 to 5 mm thick crosslinked film obtained by crosslinking the acrylic copolymer fine particles (A) with the hydrazine derivative (B) is a temperature of 160 ° C. or higher. The aqueous acrylic copolymer composition according to claim 1, which extends to an area. The aqueous acrylic copolymer composition according to claim 1, wherein the foaming agent (C) is an alkyl (or alkenyl) sulfate ester salt having 8 to 20 carbon atoms. The aqueous acrylic copolymer composition according to claim 1, wherein the foaming agent (C) is sodium lauryl sulfate. The aqueous acrylic copolymer composition according to claim 1, wherein the foam stabilizer (D) is an ammonium salt of a fatty acid having 12 to 20 carbon atoms. The aqueous acrylic copolymer composition according to claim 18, wherein the fatty acid is mainly composed of stearic acid. The foaming agent (C) is used in an amount of 0.5 to 5 parts by weight and the foam stabilizer (D) is used in an amount of 1 to 10 parts by weight with respect to 100 parts by weight of the acrylic copolymer fine particles (A). Acrylic copolymer aqueous composition. The aqueous acrylic copolymer composition according to claim 1, which is used for forming a foamed layer on a fiber substrate. The acrylic copolymer aqueous composition according to claim 1 or 21, wherein the foam layer is composed of open cells. 23. The acrylic copolymer aqueous composition according to claim 21, wherein the amount of the inorganic compound in the foamed layer is 50% by weight or less based on the weight of the foamed layer. The acrylic copolymer aqueous composition according to any one of claims 21 to 23, wherein the density of the foamed layer is in the range of 0.2 to 0.7 g / cm ³ . 25. The acrylic copolymer aqueous composition according to any one of claims 1 and 21 to 24, wherein the foamed layer has a sound absorption coefficient of 0.6 or more at a frequency of 4000 Hz by a normal incident sound absorption coefficient method. The acrylic copolymer aqueous composition according to any one of claims 1 and 21 to 25, wherein the foamed layer is provided in an option mat in an automobile cabin.

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