JP3687008B2 - Water-swellable cross-linked foam sealant - Google Patents
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Description
【０００１】
【産業状の利用分野】
本発明は水膨潤性を有する架橋発泡シ−リング材に関し、特にトンネル工事又は上下水道工事のセグメント間の防水用シ−リング、地下構造物の止水板建築物外壁パネルの間隙のシ−リング等の土木および建築用シ−リング材として使用される架橋発泡シ−リング材に関する。
【０００２】
【従来の技術】
特開昭５９−１４８６４６号公報には、ゴムまたは樹脂に特定の高吸水性高分子と無機充填材を配合し、架橋発泡する事で耐水性の優れた水膨潤性発泡体が得られる事が開示されており、このものがシ−リング材として適用されることが記載されている。しかしながら、このものの発泡倍率を３倍以上に高めると、単に吸水膨潤となるだけで、シ−リング材として必要な止水性が全く発現して来ないことが明らかとなった。
一方、特開平６−８０８１０号公報には特定のオレフィン系熱可塑性エラストマ−に対して吸水性樹脂などを配合し発泡の前後で電離性放射線を照射して８倍以下の発泡倍率とするもので、いわゆる吸水時の吸水樹脂の損失（ゲル抜け）の改良をしたものである。ところが、この技術による方法によっても発泡倍率３倍を越えると吸水膨潤するがシ−リング材として必要な止水性が発現せず、また、極めて吸水樹脂の添加量が多い場合は、吸水樹脂が溶出して徐々に止水性が低下し、最終的に全く止水性がなくなることが明らかとなった。
以上の様に、吸水性樹脂を添加した吸水膨潤性の発泡体は提案されているが、低密度発泡体であってシ−リング材として止水性の高いものは、未だ見出されていなかった。更に、従来吸水性樹脂の配合量が少量であって、吸水性樹脂の溶出がなく長期の止水性を満足できる発泡シ−リング材はまったく見出されていなかった。
【０００３】
【発明が解決しようとする課題】
本発明者は種々検討した結果、樹脂またはゴム、もしくは樹脂及びゴムからなるマトリックスに吸水高分子を配合してなる長期の止水性を満足できる低密度発泡体シ−リング材を提供する為には、配合して得られる架橋発泡体自体の水膨張率の特定と気泡径の特定をすることが重要であるとの知見を得た。つまり水膨張率の特定とは吸水高分子および親水性充填材の配合量の範囲とこれらを含んだ架橋発泡体のマトリックスの弾性率の範囲を特定することである。また、気泡径の特定とは、架橋発泡体の平均気泡径の範囲を特定することである。これらの範囲を特定することで膨張圧力が高まると同時に高止水性を有し、かつ吸水高分子の溶出の少ない水膨潤性架橋発泡体が得られることを究明し、低密度であっても優れた発泡体シ−リング材を提供できることがわかった。
【０００４】
【課題を解決するための手段】
本発明の要旨は、樹脂またはゴム、もしくは樹脂およびゴムからなるマトリックス１００重量部に対し、粒子状吸水高分子が５〜４０重量部、親水性充填材が５〜４０重量部、架橋剤、発泡剤を含んだ混合物を発泡、架橋させて得た低密度水膨潤性架橋発泡シ−リング材であって、当該架橋発泡シ−リング材の平均気泡径が５００μｍ以下でかつ架橋発泡シ―リングの弾性率が１００〜１５００Ｋｇｆ／ｃｍ２、独立気泡率が１０％以上である事を特徴とする低密度水膨潤性架橋発泡シ−リング材である。
即ち、本発明は上述のような割合で粒子状吸水高分子及び親水性充填材を配合し、これを発泡、架橋して発泡体のマトリックスの弾性率を１００〜１５００Ｋｇｆ／ｃｍ２に特定し、同時に架橋発泡体の平均気泡径を５００μｍ以下、独立気泡率が１０％以上に特定することによって所期の目的を達成することができる。
【０００５】
本発明のシ−リング材は、樹脂またはゴム、もしくは樹脂およびゴムをマトリックスとし粒子状吸水高分子、発泡剤および親水性充填材を含んだ低密度水膨潤性架橋発泡体よりなる。
まず、発泡体を構成する本発明に使用されるマトリックスのゴムは、天然ゴムの他、ポリイソプレンゴム、ポリブタジエンゴム、クロロプレンゴム、ブチルゴム、エチレン−プロピレン共重合体、スチレン−ブタジエン共重合体、アクリロニトリル−ジエン共重合体、エチレン−αオレフィン−非共役ジエン共重合体（ＥＰＤＭゴム）、シリコンゴム、ウレタンゴムなどの各種合成ゴムが挙げられる。
マトリックスの樹脂は、低密度ポリエチレン、ポリプロピレン、エチレン−酢酸ビニル共重合体もしくはそのケン化物、エチレン−アクリル酸共重合体、エチレン−イソブチレン共重合体、エチレン−アクリル酸共重合体、エチレン−スチレン共重合体、塩素化ポリエチレン、クロロスルホン化ポリエチレン、ポリ塩化ビニル、塩化ビニル共重合体、スチレン−ブタジエン−スチレンブロック共重合体、スチレン−イソプレン−スチレンブロック共重合体などの各種の熱可塑性樹脂または熱可塑性エラストマ−が挙げられる。なお、本発明のゴムおよび樹脂は、単独または併用して用いることができる。
特に、ＥＰＤＭゴム１０〜８０重量部に対し、ポリエチレン、ポリプロピレンまたはエチレン酢酸ビニル共重合体が９０〜２０重量部の配合比でブレンドされたマトリックス系が好ましい。
【０００６】
本発明に用いられる粒子状吸水高分子とは、とくに制限されず従来より公知各種のものが使用できる。酢酸ビニル−アクリル酸エステル共重合体ケン化物、イソブチレン−無水マレイン酸共重合体ケン化物の架橋物、架橋を有するポリアクリル酸塩、デンプン−アクリル酸塩グラフト重合体などの高分子アルカリ金属塩が好ましい。その他のカルボキシメチルセル−ス架橋体、変性ポリビニルアルコ−ル等もある。
本発明に用いられる吸水高分子の配合量は５〜４０重量部、特に１０〜４０重量部が好ましい。５重量部以下では膨潤速度が遅く、膨潤率が小さ過ぎ、４０重量部以上になると低密度発泡体を得るに適当な架橋が起こりにくく、弾性率が低くなり、その結果マトリックス中からの吸水高分子の溶出が大きくなり長期の止水性が悪くなる。
【０００７】
また、本発明に用いられる吸水高分子は、分子内および分子間架橋された分子構造の吸水高分子で、これらの粒径は１５μｍ〜２００μｍの範囲のもので吸水高分子は吸水膨潤倍率が１００〜６００倍のものを用いる。吸水高分子の粒径が１５μｍ以下では、配合量が少ない場合、吸水高分子の粒子が気泡の膜や骨格中に取込まれ、吸水膨潤圧が出てこない。また、配合量が多い場合、吸水膨潤が進む際に気泡の膜や骨格中から脱落した吸水高分子は、容易に溶出し易くなる。一方、吸水高分子の粒径が２００μｍ以上では、配合量が多い場合、吸水膨潤が進む際に気泡の膜や骨格中から容易に脱落し溶出し易くなる。また、吸水高分子の吸水膨潤倍率は１００倍以下のものでは膨潤圧が小さく、６００倍以上のものでは吸水膨潤が進む際に気泡の膜や骨格中から脱落し、溶出し易くなる。
【０００８】
本発明に用いられる親水性の充填材とは、マトリックス１００重量部に対して充填材５〜４０重量部配合した混合物のプレスシ−ト成形物の接触角が９０度以上のものを言う。
例えば無機充填材で、セッコウ、クレ−、カオリン、シリカ、ケイソウ土、水酸化アルミニウム、酸化亜鉛、水酸化マグネシウム、酸化カルシウム、酸化マグネシウム、酸化チタン、マイカ、ヴェントナイト、シラスバル−ン、ゼオライト、珪酸白土、セメント、シリカフュ−ム等がある。有機充填剤としてはパルプ、繊維状チップ、カンテン等が挙げられる。
これらの親水性充填材の中で特にクレ−やヴェントナイト、シリカが好ましい。
本発明に用いられる親水性充填材の配合部数は５〜４０重量部が好ましい。配合部数が５重量部以下では発泡体への水の浸透性が悪く、従って膨潤速度が遅く膨潤率も小さいものになってしまう。一方配合部数が４０重量部以上になると、低密度発泡体を得にくくなり、また吸水高分子の溶出がし易く、従って耐水性が乏しくなる。
【０００９】
また、本発明のシ−リング材を構成する発泡体とは、熱分解型発泡剤の熱分解より出てくるガスによって発泡した物を言う。本発明に用いられる熱分解型発泡剤は、ジエチルアゾカルボキシレ−ト、アゾジカルボンアミド、アゾジカルボン酸バリウム、４，４’−オキシビス（ベンゼンスルホニルヒドラジド）、３，３’−ジスルホンヒドラジドフェニルスルホン酸、Ｎ，Ｎ’−ジニトロソペンタメチレンテトラミン等がある。
本発明に用いられる化学架橋とは、当該技術分野で公知の方法がいずれも使用でき、代表的な例として、過酸化物架橋と硫黄架橋が挙げられる。いずれにおいても架橋発泡後の発泡体の気泡構成材料の引張り弾性率は１００Ｋｇｆ／ｃｍ2〜１５００Ｋｇｆ／ｃｍ2に調整する。
すなわち、架橋発泡シ−リング材の弾性率が１００〜１５００Ｋｇｆ／ｃｍ2である。弾性率が１５００Ｋｇｆ／ｃｍ2以上の高すぎるものは、いくら吸水性高分子や親水性充填材の配合量を増やしても、また気泡径を小さくしても気泡を構成する架橋マトリックスの応力の方が吸水高分子の気泡内膨潤圧力よりも勝り膨張圧力は出て来ない。一方、弾性率が１００Ｋｇｆ／ｃｍ2以下の架橋発泡体の場合、膨張初期に膨張圧力が出ることがあっても、更に膨張が進むことで気泡膜は破壊され、膨潤気泡径は吸水高分子の膨潤粒径よりも大きくなり吸水高分子が溶出し易くなる。
【００１０】
また、電離性放射線架橋については、前に述べたように当該技術分野の公知の方法で行うことができるが、特に工業化されている電子線架橋では表面部分は架橋されるが内部まで架橋しないのであまり好ましくない。
その他必要に応じて各種充填材、安定剤、架橋助剤、架橋促進剤、軟化剤、可塑剤など通常用いられるものはすべて使用することができる。
以上の様な必須材料と必要に応じて使用する材料はいずれも均一に混練して各種の形状に成形される。この様な混練および成形方法も当該技術分野で公知の方法がいずれも使用でき、代表的な例として、混練方法ではロ−ル、バンバリ−ミキサ−、ニ−ダ−等があり、成形方法ではカレンダ−ロ−ル、単軸押出成形機、プレス成形機、混練成形方法では２軸混練押出成形機、発泡成形方法では熱風循環加熱、ソルト浴加熱、オイル浴加熱、赤外線加熱、高周波加熱等の手段がある。
なお、これらの混練および成形方法はそれぞれ組合せ複数併用して用いることもできる。この様な方法によりシ−ト状、異形状あるいはその他の形状の止水材料とすることができる。
【００１１】
【作用】
吸水高分子を配合した水膨潤発泡体については、吸水し膨張することは良く知られているが、膨張圧力の出る発泡倍率の高い発泡体は知られていなかった。そもそも樹脂またはゴムからなるマトリックスに吸水高分子を配合してなる発泡体の場合、吸水高分子は発泡体気泡の骨格ないしは気泡膜中に取込まれ、吸水し膨張はするが膨張圧は発現せず、従って止水性を出すには、密度が０．３ｇ／ｃｍ3以上の高密度発泡体のみ可能であり、それより低密度発泡体では不可能であった。
【００１２】
その為本発明の水膨潤性の低密度発泡体では、吸水高分子および親水性充填材を特定量範囲で配合し、かつ気泡径を特定範囲内に小さくした。すなわち樹脂およびゴム、またはゴムからなるマトリックス１００重量部に対し、吸水高分子が５〜４０重量部、親水性充填材が５〜４０重量部の混合物とし、平均気泡径が５００μｍ以下の発泡体である。この事により、気泡骨格は細かく、かつ気泡膜は薄くなり、更に合せて親水性充填材により気泡骨格および気泡膜の強度が弱くなる。吸水し膨潤開始すると気泡骨格および気泡膜中に取込まれていた吸水高分子の一部またはその多くが膨張力により気泡骨格および気泡膜より気泡中に脱落する。この吸水高分子が更に吸水し気泡内で膨張をする。その時、気泡中で特に架橋マトリックス樹脂の集合している気泡骨格部は気泡内に閉じ込められた吸水高分子の膨張により３次元方向に延伸される。その為発泡体は乾燥時に比べ全体が膨張すると同時に、発泡体の硬さが大幅に増加する。この膨張圧力と気泡空間の目止め効果により止水性が発現するのである。
【００１３】
更に水膨潤発泡体の体積膨張率が膨潤圧力と深く係わっている事が究明された。つまり、体積膨張率は、水膨潤発泡体を構成する架橋マトリックス基材の弾性率と関係があり、これを特定範囲に限定する必要がある。すなわち、架橋発泡シ−リング材の弾性率が１００〜１５００Ｋｇｆ／ｃｍ2である。弾性率が１５００Ｋｇｆ／ｃｍ2以上の高すぎるものは、いくら吸水性高分子や親水性充填材の配合量を増やしても、また気泡径を小さくしても気泡を構成する架橋マトリックスの応力の方が吸水高分子の気泡内膨潤圧力よりも勝り膨張圧力は出て来ない。
【００１４】
一方、弾性率が１００Ｋｇｆ／ｃｍ2以下の架橋発泡体の場合、膨張初期に膨張圧力が出ることがあっても、更に膨張が進むことで気泡膜は破壊をされ、膨潤気泡径は吸水高分子の膨潤粒径よりも大きくなる。その結果、吸水高分子が気泡内から脱離、溶出してしまい膨潤圧力が低下し、従って止水性も出て来なくなる。またここで用いる吸水高分子は分子内あるいは分子間架橋された粒径１０μｍ〜２００μｍで吸水膨潤倍率が１００〜６００倍のものに限る。
以上の様に膨潤圧力の高い良好な低密度の発泡シ−リング材を得る為には、マトリックスとなる樹脂またはゴムに限定した範囲の吸水高分子と親水性充填材を特定量配合し、得られる発泡体を構成する架橋マトリックス基材の引張り弾性率と気泡径を特定することにより得られる。
【００１５】
また、本発泡体は架橋発泡体である必要がある。特に好ましい架橋の方法としては過酸化物架橋又は硫黄架橋による方法である。過酸化物架橋又は硫黄架橋による方法は、厚物製品のすべての部分で架橋が均一に起こり耐久性の高い発泡シ−リング材が得られる。一方、電離性放射線による方法で特に工業化されている電子線架橋では表面部分は架橋されるが内部まで架橋しないのであまり好ましくない。
また、発泡体の独立気泡率については、膨潤スピ−ドの早い物を必要とする場合は独立気泡率の低い事が有利である。しかし、独立気泡率が１０％以上になると気泡内からの吸水高分子の脱離、溶出が起こりずらくなるので耐久性が向上し好ましい。
【００１６】
【実施例】
以下に実施例と比較例を挙げて具体的に説明する。各実施例及び比較例の配合処方、密度、７０％圧縮時の防水性能および溶出率等、諸物性を表１〜表５に示す。
なお、諸物性値の試験方法は以下に示す通りである。
（１）引張り弾性率：
架橋発泡シ−リング材を基材の軟化温度付近で５０Ｋｇｆ／ｃｍ2荷重で熱プレスし、最終的に厚み０．３〜０．６ｍｍのフィルムになるように調整したものを、引張り試験サンプルとした。引張り試験の測定は、試験速度が２００ｍｍ／ｍｉｎで、応力−歪曲線を求め、初期の立ち上がりの弾性領域から弾性率を求めた。
（２）平均気泡径：
５０倍顕微鏡にて、３．３ｍｍ角あたりの気泡数が、ｎ個のとき下記式で表す。
【００１７】
【数１】
（３）７０％圧縮硬さ：
発泡シ−ト状物から縦横（水平方向）が３０ｍｍ角の試験片を切り出した試験片を試験速度５０ｍｍ／ｍｉｎで圧縮した時の応力−歪曲線を求め、その曲線から７０％圧縮時の応力を圧縮硬さとした。同様に切出した試験片を水に５日間浸漬させた時の７０％圧縮硬さも測定し、これを５日間浸漬後の７０％圧縮硬さとした。
（４）７０％圧縮防水性能：
発泡シ−ト状物から、内径が９０ｍｍ、外径が１００ｍｍのド−ナッツ状試験片を打抜き、この試験片を２枚のアクリル板で７０％圧縮率で挟み、アクリル板の一方に開けられた導水孔から水圧をかけ防水試験を行った。水圧の昇圧速度は０．１Ｋｇｆ／ｃｍ2／５ｍｉｎで行い漏水する直前の水圧値を防水性能とした。また、７０％圧縮の状態で水に５日間浸漬させた後の試料についても同様の試験方法で測定し、これを５日間膨潤後の防水性能とした。
（５）溶出率：
シ−ト状物から試験片を取り出し、７０℃温水に３日間浸漬させた後、５０℃１週間乾燥させ、試料中に配合した吸水高分子の溶出率を測定した。
【００１９】
【数２】
（６）独立気泡率（独泡率）
発泡シ−ト状物から縦横（水平方向）が３０ｍｍ角の試験片を切り出し、厚みもこれらを積み重ねて約３０ｍｍになる様に調整したものを試験片とし、Ｒａｍｉｎｇｔｏｎ Ｐａｒｉｓｅｒ法（ＡＳＴＭ Ｄ１９４０−６２Ｔ）に準じて測定した。
【００２１】
実施例１
表１の実施例１に示した配合処方で粒径が５０μｍのポリアクリル酸塩の吸水高分子とクレ−の無機充填材の混合物からなるペレットを２軸混練押出成形機で、発泡剤および過酸化物架橋材を表１に示した配合比で混練し、４ｍｍ厚、２００ｍｍ幅でシ−ト状に押出した。これを２２０℃の熱風循環炉で加熱発泡したところ、密度が０．０８３（ｇ／ｃｍ3）の長尺シ−ト物が得られた。これについての諸々の試験結果を表１に示した。
実施例２
表１の実施例２に示した配合処方で粒径が７０μｍのイソブチレン無水マレイン酸塩の吸水高分子とヴェントナイトの無機充填材をニ−ダ−及びロ−ルで混練し、これをプレスシ−ト成形して４ｍｍ厚、２００ｍｍ角のシ−ト状にした。これを１６０℃の熱風循環炉で加熱発泡させたところ、密度が０．０６５（ｇ／ｃｍ3）のシ−ト状物が得られた。これについての諸々の試験結果を表１に示した。実施例３
表１の実施例３に示した配合処方で粒径が１００μｍのイソブチレン無水マレイン酸塩の吸水高分子とクレ−の無機充填材をニ−ダ−およびロ−ルで混練し、これをプレスシ−ト成形して４ｍｍ厚、２００ｍｍ角のシ−ト状にした。これを２２０℃の熱風循環炉で加熱処理し、発泡させたところ、密度が０．０５４（ｇ／ｃｍ3）のシ−ト状物が得られた。これについての諸々の試験結果を表１に示した。
【００２２】
【表１】
実施例４
表２の実施例４に示した配合処方で粒径が５０μｍのポリアクリル酸塩の吸水高分子とクレ−の無機充填材の混合物からなるペレットを２軸混練押出成形機で、発泡剤および過酸化物架橋材を表２に示した配合比で混練し、４ｍｍ厚、２００ｍｍ幅でシ−ト状に押出した。これを２２０℃の熱風循環炉で加熱発泡したところ、密度がそれぞれ０．１１４（ｇ／ｃｍ3）、０．２９（ｇ／ｃｍ3）の長尺シ−ト物が得られた。これについての諸々の試験結果を表２に示した。
実施例５
表２の実施例５に示した配合処方で粒径が１００μｍのイソブチレン無水マレイン酸塩の吸水高分子とクレ−の無機充填材をニ−ダ−およびロ−ルで混練し、これをプレスシ−ト成形して４ｍｍ厚、２００ｍｍ角のシ−ト状に押出した。これを２２０℃の熱風循環炉で加熱処理し、発泡させたところ、それぞれ密度が０．１１７（ｇ／ｃｍ3）、０．３１（ｇ／ｃｍ3）のシ−ト状物が得られた。これについての諸々の試験結果を表２に示した。
【００２４】
【表２】
比較例１
表３の比較例１に示した配合処方でウレタン樹脂の吸水性高分子とシリカの充填材をニ−ダ−及びロ−ルで混練し、これをプレスシ−ト成形して４ｍｍ厚、２００ｍｍ角のシ−ト状にした。これを１６０℃の熱風循環炉で加熱処理することで、密度が０．４５（ｇ／ｃｍ3）のシ−ト状物が得られた。これについての諸々の試験結果を表３に示した。ここではマトリックス弾性率が小さい為に、吸水高分子の溶出が大きく、従って長期の膨潤圧力が安定して得られず、止水性も低下していく。
比較例２
表３の比較例２に示した配合処方で粒径５０μｍのポリアクリル酸塩の吸水高分子とクレ−の充填材をニ−ダ−及びロ−ルで混練し、これをプレスシ−ト成形して４ｍｍ厚、２００ｍｍ角のシ−ト状にした。これを１６０℃の熱風循環炉で加熱処理することで、密度が０．０６（ｇ／ｃｍ3）のシ−ト状物が得られた。これについての諸々の試験結果を表３に示した。ここではマトリックス弾性率が大きすぎて、吸水膨潤が進まない為、膨潤圧が得られず、発泡体は応力緩和するのみで、従って止水性が低くなる。
【００２６】
比較例３
表３の比較例３に示した配合処方で粒径５０μｍのイソブチレン−無水マレイン酸塩の吸水性高分子とクレ−の充填材をニ−ダ−及びロ−ルで混練し、これをプレスシ−ト成形して４ｍｍ厚、２００ｍｍ角のシ−ト状にした。これを２２０℃の熱風循環炉で加熱発泡することで、密度が０．２０（ｇ／ｃｍ3）のシ−ト状物が得られた。これについての諸々の試験結果を表３に示した。ここでは発泡体の平均気泡径が大きすぎる為、発泡体の吸水膨張に伴う吸水高分子の気泡中からの脱離と同時に吸水高分子粒子の溶出が大きく、従って膨潤圧力が減少し、止水性が低下していく。
【００２７】
【表３】
比較例４
表４の比較例４に示した配合処方で粒径５０μｍのポリアクリル酸塩の吸水性高分子とシリカの充填材をニ−ダ−及びロ−ルで混練し、これをプレスシ−ト成形して３．４ｍｍ厚、２００ｍｍ角のシ−ト状にした。これを１６０℃の熱風循環炉で加熱発泡することで、密度が０．６８（ｇ／ｃｍ3）のシ−ト状物が得られた。これについての諸々の試験結果を表４に示した。ここでは親水性充填材の配合量が多すぎる為に、吸水高分子の溶出が大きく、従って長期の膨潤圧力が安定して得られず、止水性も低下していく。
比較例５
表４の比較例５に示した配合処方で粒径５０μｍのポリアクリル酸塩の吸水性高分子とクレ−の充填材をニ−ダ−及びロ−ルで混練し、これをプレスシ−ト成形して４．２ｍｍ厚、２００ｍｍ角のシ−ト状にした。これを１６０℃の熱風循環炉で加熱処理することで、密度が０．７６（ｇ／ｃｍ3）のシ−ト状物が得られた。これについての諸々の試験結果を表４に示した。ここでは、吸水性高分子の配合量が多すぎる為に、吸水高分子の溶出が大きく、従って長期の膨潤圧力が安定して得られず、止水性も低下していく。
【００２９】
比較例６
表４の比較例６に示した配合処方で粒径５０μｍのイソブチレン−無水マレイン酸塩の吸水性高分子とクレ−の充填材をニ−ダ−及びロ−ルで混練し、これをプレスシ−ト成形して４ｍｍ厚、２００ｍｍ角のシ−ト状にした。これを２２０℃の熱風循環炉で加熱発泡することで、密度が０．０４５（ｇ／ｃｍ3）のシ−ト状物が得られた。これについての諸々の試験結果を表４に示した。ここでは、吸水性高分子の配合量が少なすぎる為、吸水膨潤が進まず膨潤圧が出て来ないので発泡体は応力緩和するのみで、従って止水性が低くなる。
【００３０】
【表４】
比較例７
表４の比較例７に示した配合処方で粒径３０μｍのイソブチレン−無水マレイン酸塩の吸水性高分子とクレ−の充填材をニ−ダ−及びロ−ルで混練し、これをプレスシ−ト成形して４ｍｍ厚、２００ｍｍ角のシ−ト状にした。これを２２０℃の熱風循環炉で加熱発泡することで、密度が０．０５１（ｇ／ｃｍ3）のシ−ト状物が得られた。これについての諸々の試験結果を表５に示した。ここでは、親水性充填材の配合量が少なすぎ、吸水膨潤が進まず膨潤圧が出て来ないので、発泡体は応力緩和するのみで、従って止水性が低くなる。
【００３２】
【表５】
【発明の効果】
本発明の水膨潤性架橋発泡シ−リング材は、低密度発泡であっても、優れた膨潤圧力を発現し良好な止水性を発揮する。また低密度であることから各種構造物に貼り付け施工しても軽量な為、接着剥がれが起きにくく、防水施工がし易く、コンクリ−ト表面の凹凸に対しても低密度柔軟発泡体のため、追従し易く止水性が発揮し易い。また、吸水高分子が溶出しにくい発泡体のため、長期の止水が獲得できる。また、厚みが厚い発泡体であっても、均一な止水性と耐久性が獲得できる。
従って、本発明の水膨潤性架橋発泡シ−リング材は、トンネルや上下水道工事のセグメント間の防水用シ−ル、地下構造物の止水板、建築物外壁のパネルの間隙のシ−ルなどの土木及び建築工事の発泡止水材や各種構造物の止水材として広範囲な用途に用いられる。[0001]
[Industrial application fields]
The present invention relates to a cross-linked foamed sealing material having water swellability, and in particular, sealing for waterproofing between segments of tunnel construction or water and sewage construction, sealing of gaps in outer wall panels of water blocking plates in underground structures. The present invention relates to a crosslinked foamed sealing material used as a civil engineering and architectural sealing material.
[0002]
[Prior art]
JP-A-59-148646 discloses that a water-swellable foam having excellent water resistance can be obtained by blending a specific superabsorbent polymer and an inorganic filler into rubber or resin and crosslinking and foaming. It is disclosed that this is applied as a sealing material. However, it has been clarified that when the expansion ratio of this material is increased to 3 times or more, the water-absorbing swelling is merely caused and the water stoppage necessary for the sealing material does not appear at all.
On the other hand, JP-A-6-80810 discloses that a specific olefinic thermoplastic elastomer is mixed with a water-absorbing resin and irradiated with ionizing radiation before and after foaming to obtain a foaming ratio of 8 times or less. This is an improvement in the loss of water-absorbing resin (gel loss) during so-called water absorption. However, even if this method is used, the water absorption swells when the expansion ratio exceeds 3 times. However, the water stoppage necessary as a sealing material does not appear, and if the amount of the water absorption resin is very large, the water absorption resin is eluted. As a result, it was revealed that the water-stopping property gradually decreased and finally there was no water-stopping property.
As described above, a water-absorbing swellable foam to which a water-absorbent resin is added has been proposed, but a low-density foam having a high water-stopping property has not yet been found. . Furthermore, no foamed sealing material has been found so far that the blending amount of the water-absorbing resin is small, the water-absorbing resin is not eluted, and long-term water-stopping can be satisfied.
[0003]
[Problems to be solved by the invention]
As a result of various studies, the present inventor has provided a low-density foam sealing material that can satisfy a long-term water-stopping property, in which a water-absorbing polymer is blended with a matrix made of resin or rubber, or resin and rubber. The present inventors have found that it is important to specify the water expansion coefficient and the cell diameter of the crosslinked foam itself obtained by blending. That is, the specification of the water expansion coefficient is to specify the range of the blending amount of the water-absorbing polymer and the hydrophilic filler and the range of the elastic modulus of the matrix of the cross-linked foam containing them. Also, the specification of the cell diameter is to specify the range of the average cell diameter of the crosslinked foam. By specifying these ranges, we investigated that a water-swellable cross-linked foam with high water-stopping properties and low elution of water-absorbing polymers can be obtained by increasing the expansion pressure. It has been found that a foam sealing material can be provided.
[0004]
[Means for Solving the Problems]
The gist of the present invention is that 5 to 40 parts by weight of a particulate water-absorbing polymer, 5 to 40 parts by weight of a hydrophilic filler, 100 parts by weight of a resin or rubber, or a matrix made of resin and rubber, a crosslinking agent, and foam A low-density water-swellable crosslinked foamed sealing material obtained by foaming and crosslinking a mixture containing an agent, wherein the crosslinked foamed sealing material has an average cell diameter of 500 μm or less and a crosslinked foamed sealing material. A low-density water-swellable crosslinked foamed sealing material characterized by an elastic modulus of 100 to 1500 Kgf / cm 2 and a closed cell ratio of 10% or more .
That is, the present invention blends the particulate water-absorbing polymer and the hydrophilic filler in the above-mentioned proportions, foams and cross-links them to specify the elastic modulus of the foam matrix to 100-1500 Kgf / cm 2 , At the same time, the intended purpose can be achieved by specifying the average cell diameter of the crosslinked foamed material to 500 μm or less and the closed cell ratio to 10% or more .
[0005]
The sealing material of the present invention comprises a resin or rubber, or a low density water-swellable crosslinked foam containing resin and rubber as a matrix and a particulate water-absorbing polymer, a foaming agent and a hydrophilic filler.
First, the matrix rubber used in the present invention constituting the foam is not only natural rubber but also polyisoprene rubber, polybutadiene rubber, chloroprene rubber, butyl rubber, ethylene-propylene copolymer, styrene-butadiene copolymer, acrylonitrile. Examples include various synthetic rubbers such as a diene copolymer, an ethylene-α olefin-nonconjugated diene copolymer (EPDM rubber), silicon rubber, and urethane rubber.
The matrix resin is low density polyethylene, polypropylene, ethylene-vinyl acetate copolymer or saponified product thereof, ethylene-acrylic acid copolymer, ethylene-isobutylene copolymer, ethylene-acrylic acid copolymer, ethylene-styrene copolymer. Various thermoplastic resins such as polymers, chlorinated polyethylene, chlorosulfonated polyethylene, polyvinyl chloride, vinyl chloride copolymers, styrene-butadiene-styrene block copolymers, styrene-isoprene-styrene block copolymers, or heat A plastic elastomer is mentioned. In addition, the rubber | gum and resin of this invention can be used individually or in combination.
In particular, a matrix system in which polyethylene, polypropylene or ethylene vinyl acetate copolymer is blended at a blending ratio of 90 to 20 parts by weight with respect to 10 to 80 parts by weight of EPDM rubber is preferable.
[0006]
The particulate water-absorbing polymer used in the present invention is not particularly limited and various conventionally known polymers can be used. High molecular alkali metal salts such as vinyl acetate-acrylic acid ester copolymer saponified products, cross-linked products of isobutylene-maleic anhydride copolymer saponified products, polyacrylates having crosslinks, starch-acrylate graft polymers, etc. preferable. There are other carboxymethyl cellulose cross-linked products, modified polyvinyl alcohol, and the like.
The amount of the water-absorbing polymer used in the present invention is preferably 5 to 40 parts by weight, particularly 10 to 40 parts by weight. If the amount is 5 parts by weight or less, the swelling rate is slow, the swelling rate is too small, and if it is 40 parts by weight or more, suitable crosslinking for obtaining a low-density foam is difficult to occur, resulting in a low elastic modulus, resulting in high water absorption from the matrix. The elution of molecules becomes large, and the long-term water stoppage becomes worse.
[0007]
In addition, the water-absorbing polymer used in the present invention is a water-absorbing polymer having a molecular structure which is cross-linked between molecules and between molecules, and the particle size thereof ranges from 15 μm to 200 μm, and the water-absorbing polymer has a water absorption swelling ratio of 100. Use up to 600 times. When the water-absorbing polymer has a particle size of 15 μm or less, when the blending amount is small, the water-absorbing polymer particles are taken into the bubble film or skeleton, and the water-absorbing swelling pressure does not appear. Further, when the blending amount is large, the water-absorbing polymer that has fallen out of the bubble film or skeleton as the water-absorbing swelling progresses is easily eluted. On the other hand, when the water-absorbing polymer has a particle size of 200 μm or more, when the amount of the water-absorbing polymer is large, the water-absorbing swelling easily drops off from the bubble film or skeleton when the water-absorbing swelling proceeds. Further, when the water absorption swelling ratio of the water-absorbing polymer is 100 times or less, the swelling pressure is small, and when it is 600 times or more, when the water absorption swelling progresses, it drops off from the bubble film or skeleton and is easily eluted.
[0008]
The hydrophilic filler used in the present invention refers to a material having a contact angle of 90 ° or more of a press sheet molded product of a mixture in which 5 to 40 parts by weight of a filler is blended with 100 parts by weight of a matrix.
For example, inorganic filler, gypsum, clay, kaolin, silica, diatomaceous earth, aluminum hydroxide, zinc oxide, magnesium hydroxide, calcium oxide, magnesium oxide, titanium oxide, mica, bentonite, shirasu balun, zeolite, silicic acid There are white clay, cement and silica fume. Examples of the organic filler include pulp, fibrous chips, agar and the like.
Among these hydrophilic fillers, clay, bentonite, and silica are particularly preferable.
The amount of the hydrophilic filler used in the present invention is preferably 5 to 40 parts by weight. When the blending number is 5 parts by weight or less, the water permeability to the foam is poor, and therefore the swelling speed is slow and the swelling rate is small. On the other hand, when the number of blended parts is 40 parts by weight or more, it becomes difficult to obtain a low-density foam, and the water-absorbing polymer is easily eluted, resulting in poor water resistance.
[0009]
Moreover, the foam which comprises the sealing material of this invention means the thing foamed with the gas emitted from the thermal decomposition of a thermal decomposition type foaming agent. The pyrolytic foaming agent used in the present invention is diethyl azocarboxylate, azodicarbonamide, barium azodicarboxylate, 4,4′-oxybis (benzenesulfonylhydrazide), 3,3′-disulfonehydrazide phenylsulfonic acid. , N, N′-dinitrosopentamethylenetetramine and the like.
As the chemical crosslinking used in the present invention, any method known in the art can be used, and representative examples thereof include peroxide crosslinking and sulfur crosslinking. In any case, the tensile elastic modulus of the cell constituent material of the foam after the cross-linking foaming is adjusted to 100 Kgf / cm 2 to 1500 Kgf / cm 2 .
That is, the elastic modulus of the crosslinked foamed sealing material is 100-1500 Kgf / cm 2 . If the elastic modulus is too high (1500 kgf / cm 2 or more), the stress of the cross-linked matrix that constitutes the cell is increased no matter how much the water-absorbing polymer or hydrophilic filler is added or the cell diameter is reduced. However, the pressure exceeds the swelling pressure in the bubbles of the water-absorbing polymer and no expansion pressure appears. On the other hand, in the case of a crosslinked foam having an elastic modulus of 100 Kgf / cm 2 or less, even if an expansion pressure is generated at the initial stage of expansion, the bubble film is destroyed by the further expansion, and the swollen bubble diameter is that of the water absorbing polymer. It becomes larger than the swollen particle diameter, and the water-absorbing polymer is easily eluted.
[0010]
In addition, as described above, ionizing radiation crosslinking can be carried out by a known method in the technical field, but particularly in industrialized electron beam crosslinking, the surface portion is crosslinked but not crosslinked to the inside. Not very good.
In addition, if necessary, all commonly used materials such as various fillers, stabilizers, crosslinking aids, crosslinking accelerators, softeners, plasticizers can be used.
The essential materials as described above and materials to be used as necessary are uniformly kneaded and formed into various shapes. As such a kneading and forming method, any method known in the art can be used. Typical examples of the kneading method include a roll, a Banbury mixer, and a kneader. Calendar roll, single screw extruder, press molding machine, biaxial kneading extrusion molding machine for kneading molding method, hot air circulation heating, salt bath heating, oil bath heating, infrared heating, high frequency heating, etc. for foam molding method There is a means.
A plurality of these kneading and molding methods can be used in combination. By such a method, a water-proof material having a sheet shape, a different shape, or other shapes can be obtained.
[0011]
[Action]
It is well known that a water-swelling foam containing a water-absorbing polymer absorbs water and expands, but a foam having a high expansion ratio that produces an expansion pressure has not been known. In the first place, in the case of a foam made by mixing a water-absorbing polymer with a matrix made of resin or rubber, the water-absorbing polymer is taken into the foam bubble skeleton or cell membrane and absorbs and expands but does not develop an expansion pressure. Therefore, only high density foam having a density of 0.3 g / cm 3 or more was possible to achieve water-stopping, and it was not possible with low density foam.
[0012]
Therefore, in the water-swellable low-density foam of the present invention, the water-absorbing polymer and the hydrophilic filler are blended in a specific amount range, and the bubble diameter is reduced within the specific range. That is, it is a foam having an average cell diameter of 500 μm or less with a mixture of 5 to 40 parts by weight of a water-absorbing polymer and 5 to 40 parts by weight of a hydrophilic filler with respect to 100 parts by weight of a resin and rubber or a matrix made of rubber. is there. As a result, the bubble skeleton is fine and the bubble film is thinned. In addition, the strength of the bubble skeleton and the bubble film is weakened by the hydrophilic filler. When water is absorbed and swelling starts, a part or most of the water-absorbing polymer taken into the bubble skeleton and the bubble film is dropped into the bubbles from the bubble skeleton and the bubble film due to the expansion force. The water-absorbing polymer further absorbs water and expands in the bubbles. At that time, the bubble skeleton in which the crosslinked matrix resin is gathered in the bubbles is stretched in the three-dimensional direction by the expansion of the water-absorbing polymer confined in the bubbles. As a result, the foam expands as a whole compared to when it is dried, and at the same time, the hardness of the foam increases significantly. The water stoppage is expressed by the expansion pressure and the effect of sealing the bubble space.
[0013]
Furthermore, it was found that the volume expansion coefficient of the water-swelling foam is deeply related to the swelling pressure. That is, the volume expansion coefficient is related to the elastic modulus of the crosslinked matrix base material constituting the water-swelled foam, and it is necessary to limit this to a specific range. That is, the elastic modulus of the crosslinked foamed sealing material is 100-1500 Kgf / cm 2 . If the elastic modulus is too high (1500 kgf / cm 2 or more), the stress of the cross-linked matrix that constitutes the cell is increased no matter how much the water-absorbing polymer or hydrophilic filler is added or the cell diameter is reduced. However, the pressure exceeds the swelling pressure in the bubbles of the water-absorbing polymer and no expansion pressure appears.
[0014]
On the other hand, in the case of a crosslinked foam having an elastic modulus of 100 kgf / cm 2 or less, even if an expansion pressure is generated in the early stage of expansion, the cell membrane is destroyed by further expansion, and the swollen cell diameter is the water-absorbing polymer. Larger than the swollen particle diameter. As a result, the water-absorbing polymer is desorbed and eluted from the bubbles, so that the swelling pressure is lowered, so that the water stoppage does not come out. The water-absorbing polymer used here is limited to those having an intramolecular or intermolecular cross-linked particle size of 10 μm to 200 μm and a water absorption swelling ratio of 100 to 600 times.
As described above, in order to obtain a good low density foamed sealing material having a high swelling pressure, a specific amount of a water-absorbing polymer and a hydrophilic filler in a range limited to the resin or rubber used as a matrix is blended and obtained. It is obtained by specifying the tensile elastic modulus and the cell diameter of the crosslinked matrix base material constituting the foamed product.
[0015]
Moreover, this foam needs to be a crosslinked foam. A particularly preferable crosslinking method is a method based on peroxide crosslinking or sulfur crosslinking. In the method by peroxide crosslinking or sulfur crosslinking, crosslinking is uniformly performed in all parts of the thick product, and a highly durable foamed sealing material is obtained. On the other hand, the electron beam cross-linking that has been industrialized especially by the method using ionizing radiation is not preferable because the surface portion is cross-linked but not cross-linked to the inside.
As for the closed cell ratio of the foam, it is advantageous that the closed cell ratio is low when a product having a high swelling speed is required. However, it is preferable that the closed cell ratio is 10% or more because the desorption and elution of the water-absorbing polymer from the bubbles is difficult to occur, so that the durability is improved.
[0016]
【Example】
Hereinafter, examples and comparative examples will be specifically described. Tables 1 to 5 show various physical properties such as formulation, density, waterproof performance at 70% compression, and dissolution rate of each Example and Comparative Example.
The test methods for various physical properties are as follows.
(1) Tensile modulus:
A cross-linked foamed sealing material was hot-pressed at a load of 50 kgf / cm 2 near the softening temperature of the substrate, and finally adjusted to a film having a thickness of 0.3 to 0.6 mm. did. In the measurement of the tensile test, a stress-strain curve was obtained at a test speed of 200 mm / min, and the elastic modulus was obtained from the elastic region at the initial rise.
(2) Average bubble diameter:
When the number of bubbles per 3.3 mm square is n with a 50 × microscope, the following formula is used.
[0017]
[Expression 1]
(3) 70% compression hardness:
A stress-strain curve is obtained by compressing a test piece obtained by cutting a test piece having a length and width (horizontal direction) of 30 mm square from a foamed sheet at a test speed of 50 mm / min. The compression hardness. Similarly, 70% compression hardness when the cut specimen was immersed in water for 5 days was also measured, and this was taken as 70% compression hardness after immersion for 5 days.
(4) 70% compression waterproof performance:
A doughnut-shaped test piece having an inner diameter of 90 mm and an outer diameter of 100 mm is punched out from the foamed sheet, and the test piece is sandwiched between two acrylic plates at a compression rate of 70% and opened on one side of the acrylic plate. A waterproof test was performed by applying water pressure from the water guide hole. Rate of rise of the water pressure was the pressure value immediately before water leakage conducted in 0.1Kgf / cm 2 / 5min and the waterproof performance. Further, a sample after being immersed in water for 5 days in a state of 70% compression was also measured by the same test method, and this was regarded as waterproof performance after swelling for 5 days.
(5) Dissolution rate:
A test piece was taken out from the sheet and immersed in warm water at 70 ° C. for 3 days, then dried at 50 ° C. for 1 week, and the elution rate of the water-absorbing polymer blended in the sample was measured.
[0019]
[Expression 2]
(6) Closed cell ratio (single bubble ratio)
A test piece having a length and width (horizontal direction) of 30 mm square cut out from a foamed sheet and adjusted to have a thickness of about 30 mm by stacking these pieces is used as a test piece, and a Ramton Parser method (ASTM D1940-62T). It measured according to.
[0021]
Example 1
A pellet made of a mixture of a water-absorbing polymer of polyacrylate having a particle diameter of 50 μm and an inorganic filler of clay with the formulation shown in Example 1 of Table 1 was mixed with a twin-screw kneading extruder, The oxide cross-linking material was kneaded at a blending ratio shown in Table 1 and extruded into a sheet shape with a thickness of 4 mm and a width of 200 mm. When this was heated and foamed in a hot air circulating furnace at 220 ° C., a long sheet having a density of 0.083 (g / cm 3 ) was obtained. Table 1 shows the results of various tests on this.
Example 2
A water-absorbing polymer of isobutylene maleic anhydride having a particle diameter of 70 μm and an inorganic filler of Ventonite were kneaded with a kneader and a roll with the formulation shown in Example 2 of Table 1, and this was pressed. The sheet was molded into a sheet of 4 mm thickness and 200 mm square. When this was heated and foamed in a hot air circulating furnace at 160 ° C., a sheet having a density of 0.065 (g / cm 3 ) was obtained. Table 1 shows the results of various tests on this. Example 3
A water-absorbing polymer of isobutylene maleic anhydride having a particle size of 100 μm and an inorganic filler of clay was kneaded with a kneader and a roll with the formulation shown in Example 3 of Table 1, and this was pressed. The sheet was molded into a sheet of 4 mm thickness and 200 mm square. When this was heat-treated in a hot air circulating furnace at 220 ° C. and foamed, a sheet having a density of 0.054 (g / cm 3 ) was obtained. Table 1 shows the results of various tests on this.
[0022]
[Table 1]
Example 4
Pellets made of a mixture of a water-absorbing polymer of polyacrylate having a particle size of 50 μm and an inorganic filler of clay with the formulation shown in Example 4 of Table 2 were mixed with a twin-screw kneading extruder, The oxide cross-linking material was kneaded at a blending ratio shown in Table 2, and extruded into a sheet shape with a thickness of 4 mm and a width of 200 mm. When this was heated and foamed in a hot air circulating furnace at 220 ° C., long sheets having densities of 0.114 (g / cm 3 ) and 0.29 (g / cm 3 ) were obtained. Various test results on this are shown in Table 2.
Example 5
A water-absorbing polymer of isobutylene maleic anhydride having a particle size of 100 μm and an inorganic filler of clay was kneaded with a kneader and a roll with the formulation shown in Example 5 of Table 2, and this was pressed. And then extruded into a sheet of 4 mm thickness and 200 mm square. When this was heated in a hot air circulating furnace at 220 ° C. and foamed, sheet-like materials having densities of 0.117 (g / cm 3 ) and 0.31 (g / cm 3 ) were obtained. . Various test results on this are shown in Table 2.
[0024]
[Table 2]
Comparative Example 1
A water-absorbing polymer of urethane resin and a silica filler were kneaded with a kneader and a roll with the formulation shown in Comparative Example 1 in Table 3, and this was press-sheet molded to a thickness of 4 mm, 200 mm square. It was made into the sheet form. This was heat-treated in a hot air circulating furnace at 160 ° C. to obtain a sheet-like material having a density of 0.45 (g / cm 3 ). Table 3 shows the results of various tests on this. Here, since the matrix elastic modulus is small, the elution of the water-absorbing polymer is large, so that a long-term swelling pressure cannot be stably obtained, and the water stoppage also decreases.
Comparative Example 2
A blended formulation shown in Comparative Example 2 in Table 3 was used to knead a water-absorbing polymer of polyacrylate having a particle diameter of 50 μm and a filler of clay with a kneader and a roll, and this was press-sheet molded. The sheet was 4 mm thick and 200 mm square. This was heat-treated in a hot air circulating furnace at 160 ° C. to obtain a sheet-like material having a density of 0.06 (g / cm 3 ). Table 3 shows the results of various tests on this. Here, since the matrix elastic modulus is too large and the water absorption swelling does not proceed, the swelling pressure cannot be obtained, the foam only relaxes the stress, and therefore the water stoppage is lowered.
[0026]
Comparative Example 3
A water-absorbing polymer of isobutylene-anhydride maleate having a particle size of 50 μm and a clay filler were kneaded with a kneader and a roll with the formulation shown in Comparative Example 3 in Table 3, and this was pressed into a press sheet. The sheet was molded into a sheet of 4 mm thickness and 200 mm square. This was heated and foamed in a hot air circulating furnace at 220 ° C. to obtain a sheet having a density of 0.20 (g / cm 3 ). Table 3 shows the results of various tests on this. Here, since the average cell diameter of the foam is too large, the elution of the water-absorbing polymer particles is large at the same time as the desorption of the water-absorbing polymer from the bubbles due to the water absorption expansion of the foam. Will go down.
[0027]
[Table 3]
Comparative Example 4
A water-absorbing polymer of polyacrylate having a particle size of 50 μm and a silica filler were kneaded with a kneader and a roll with the formulation shown in Comparative Example 4 in Table 4, and this was press-sheet molded. 3.4 mm thick and 200 mm square sheet. This was heated and foamed in a hot air circulating furnace at 160 ° C. to obtain a sheet-like material having a density of 0.68 (g / cm 3 ). Various test results on this are shown in Table 4. Here, since the amount of the hydrophilic filler is too large, the elution of the water-absorbing polymer is large, so that a long-term swelling pressure cannot be stably obtained, and the water stoppage also decreases.
Comparative Example 5
A water-absorbing polymer of polyacrylate having a particle size of 50 μm and a filler of clay are kneaded with a kneader and a roll with the formulation shown in Comparative Example 5 of Table 4, and this is press-sheet molded The sheet was formed into a sheet of 4.2 mm thickness and 200 mm square. This was heat-treated in a hot air circulating furnace at 160 ° C. to obtain a sheet-like material having a density of 0.76 (g / cm 3 ). Various test results on this are shown in Table 4. Here, since the amount of the water-absorbing polymer is too large, the elution of the water-absorbing polymer is large, so that a long-term swelling pressure cannot be stably obtained, and the water-stopping property also decreases.
[0029]
Comparative Example 6
A water-absorbing polymer of isobutylene-anhydride maleate having a particle size of 50 μm and a clay filler were kneaded with a kneader and a roll with the formulation shown in Comparative Example 6 of Table 4, and this was pressed into a press sheet. The sheet was molded into a sheet of 4 mm thickness and 200 mm square. This was heated and foamed in a hot air circulating furnace at 220 ° C. to obtain a sheet having a density of 0.045 (g / cm 3 ). Various test results on this are shown in Table 4. Here, since the blending amount of the water-absorbing polymer is too small, the water-absorbing swelling does not proceed and the swelling pressure does not come out, so the foam only relaxes the stress, and therefore the water-stopping property is lowered.
[0030]
[Table 4]
Comparative Example 7
A water-absorbing polymer of isobutylene-anhydride maleate having a particle diameter of 30 μm and a clay filler were kneaded with a kneader and a roll with the formulation shown in Comparative Example 7 of Table 4, and this was pressed into a press sheet. The sheet was molded into a sheet of 4 mm thickness and 200 mm square. This was heated and foamed in a hot air circulating furnace at 220 ° C. to obtain a sheet-like material having a density of 0.051 (g / cm 3 ). Various test results on this are shown in Table 5. Here, the blending amount of the hydrophilic filler is too small, and the water absorption does not swell and the swelling pressure does not come out. Therefore, the foam only relaxes the stress, and therefore the water stoppage is lowered.
[0032]
[Table 5]
【The invention's effect】
Even if the water-swellable crosslinked foamed sealing material of the present invention is a low density foam, it exhibits an excellent swelling pressure and exhibits a good water-stopping property. In addition, because of its low density, it is lightweight even when applied to various structures, making it difficult to peel off, facilitating waterproof construction, and low-density flexible foam against irregularities on the concrete surface. , Easy to follow, and easy to exhibit water-stop. In addition, since the water-absorbing polymer is difficult to elute, a long-term water stoppage can be obtained. Moreover, even if it is a foam with thick thickness, uniform water-stop and durability can be acquired.
Accordingly, the water-swellable crosslinked foamed sealant of the present invention is a waterproof seal between tunnel and water and sewage construction segments, a water blocking plate for an underground structure, and a seal for a gap between panels of a building outer wall. It is used in a wide range of applications as a foam waterproofing material for civil engineering and building construction, and as a waterproofing material for various structures.
Claims (3)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30113294A JP3687008B2 (en) | 1994-12-05 | 1994-12-05 | Water-swellable cross-linked foam sealant |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30113294A JP3687008B2 (en) | 1994-12-05 | 1994-12-05 | Water-swellable cross-linked foam sealant |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08157805A JPH08157805A (en) | 1996-06-18 |
| JP3687008B2 true JP3687008B2 (en) | 2005-08-24 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP30113294A Expired - Fee Related JP3687008B2 (en) | 1994-12-05 | 1994-12-05 | Water-swellable cross-linked foam sealant |
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Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3732625B2 (en) * | 1997-08-22 | 2006-01-05 | 早川ゴム株式会社 | Rubber composition, waterproofing material and waterproofing structure |
| JP4781052B2 (en) * | 2005-09-01 | 2011-09-28 | 電気化学工業株式会社 | Water expandable foam sealant |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5792032A (en) * | 1980-12-01 | 1982-06-08 | Nhk Spring Co Ltd | Water-retaining and water-stopping foamed material |
| JPS57123399A (en) * | 1981-01-23 | 1982-07-31 | Nhk Spring Co Ltd | Water stopping material for assembly of shielded segment |
| JPS5893775A (en) * | 1981-11-30 | 1983-06-03 | Nhk Spring Co Ltd | Hydrophilic water checking agent for assembling sealed segments |
| JPS58108232A (en) * | 1981-12-21 | 1983-06-28 | Nhk Spring Co Ltd | Water-stopping material |
| JPS59148646A (en) * | 1983-02-14 | 1984-08-25 | Sumitomo Chem Co Ltd | Water swelling foamed article |
| JPS6187749A (en) * | 1984-10-05 | 1986-05-06 | Hayashikane Zosen Kk | Water-absorptive elastomer composition |
| JPS62132941A (en) * | 1985-12-04 | 1987-06-16 | Asahi Denka Kogyo Kk | Water swelling expanded sealing material |
| JP2831648B2 (en) * | 1988-03-31 | 1998-12-02 | 住友精化株式会社 | Water-absorbing water retention material |
| JPH0665410A (en) * | 1992-08-24 | 1994-03-08 | Tonen Chem Corp | Water-absorbing resin composition foam |
| JPH0673216A (en) * | 1992-08-26 | 1994-03-15 | Tonen Chem Corp | Foam of water-absorptive resin composition |
| JPH0680810A (en) * | 1992-09-02 | 1994-03-22 | Tonen Chem Corp | Production of crosslinked and foamed material of water-absorbing resin |
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1994
- 1994-12-05 JP JP30113294A patent/JP3687008B2/en not_active Expired - Fee Related
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| JPH08157805A (en) | 1996-06-18 |
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