JP2004121400A - Absorbent and absorptive article using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an absorbent that is excellent in amount of absorption and extremely excellent in rate of absorption. <P>SOLUTION: This absorbent is constituted of surface-treated crosslinked polymer particles (X) comprising crosslinked polymer particles (S) composed of an ethylenic unsaturated monomer containing (metha)acrylic acid (salt) as a main building block and a surface modifying agent (M) having a surface tension of 10-30 dyne/cm and surface-treated crosslinked polymer particles (Y) comprising the crosslinked polymer particles (S) and a surface modifying agent (N) having a surface tension of 40-80 dyne/cm. It is preferable to use a surface modifying agent (M2) containing a hydrocarbon radical containing fluorine atoms or another surface modifying agent (M3) containing a siloxane structure as the surface modifying agent (M). In addition, it is also preferable to use polyalkylene glycol as the surface modifying agent (N). <P>COPYRIGHT: (C)2004,JPO

Description

【００４２】
生理食塩水に対する加圧下（２０ｇ／ｃｍ^２）の架橋重合体粒子（Ｓ）の吸収倍率（ｇ／ｇ）は、１５以上が好ましく、さらに好ましくは２０〜７０、特に好ましくは２５〜６０である。すなわち、生理食塩水に対する加圧下（２０ｇ／ｃｍ^２）の架橋重合体粒子（Ｓ）の吸収倍率（ｇ／ｇ）は、１５以上が好ましく、さらに好ましくは２０以上、特に好ましくは２５以上であり、またさらに好ましくは７０以下、特に好ましくは６０以下である。なお、この加圧下の吸収倍率は、以下のように測定される。すなわち、目開き６３μｍ（ＪＩＳ８８０１−１９７６）のナイロン網を底面に貼った円筒型プラスチックチューブ（内径３０ｍｍ、高さ６０ｍｍ）内に試料０．１０ｇを秤量し、プラスチックチューブを垂直にしてナイロン網上に試料がほぼ均一厚さになるように整え、この試料の上に２０ｇ／ｃｍ^２の荷重となるように外径２９．５ｍｍ×２２ｍｍ厚の分銅を乗せる。次いで、生理食塩水（食塩濃度０．９重量％）６０ｍｌの入ったシャーレ（直径：１２ｃｍ）の中に、試料及び分銅の入ったプラスチックチューブをナイロン網側を下面にして垂直にして浸し、放置する。６０分後に試料及び分銅の入ったプラスチックチューブを計量し試料が生理食塩水を吸収して増加した重量を算出する。６０分浸した後の増加量の１０倍値を生理食塩水に対する加圧下の吸収倍率（ｇ／ｇ）とする。
【００４３】
表面改質剤（Ｍ）の表面張力（ダイン／ｃｍ）は、１０〜３０が好ましく、さらに好ましくは１１〜２８、特に好ましくは１３〜２７、最も好ましくは１５〜２６である。すなわち、表面改質剤（Ｍ）の表面張力（ダイン／ｃｍ）は、１０以上が好ましく、さらに好ましくは１１以上、特に好ましくは１３以上、最も好ましくは１５以上であり、また３０以下が好ましく、さらに好ましくは２８以下、特に好ましくは２７以下、最も好ましくは２６以下である。なお、表面張力は、輪環法｛（２５℃）、Ｃ．Ｈｕｂ，Ｓ．Ｇ．Ｍａｓｏｎ，Ｃｏｌｌｏｉｄ＆ｐｏｌｙｍｅｒ　Ｓｃｉｅｎｃｅ，２５３巻（１９７４年），５６６頁記載｝により測定される。
【００４４】
表面改質剤（Ｍ）は、架橋重合体粒子（Ｓ）の表面に付着（物理吸着）又は固着（化学結合）した状態となることにより、架橋重合体粒子（Ｓ）の表面を改質するためのものである。
【００４５】
表面改質剤（Ｍ）は、架橋重合体粒子（Ｓ）と化学結合し得る結合基を有するものが好ましく、結合様式としては、水素結合、イオン結合及び共有結合等が挙げられる。なお、表面改質剤（Ｍ）は１種の結合基を有するものだけではなく、２種以上の結合基を有してもよい。架橋重合体粒子（Ｓ）と化学結合し得る結合基を有すると、架橋重合体粒子（Ｓ）の表面に安定して表面改質剤（Ｍ）が存在できるため、血液等の被吸収液体を吸収する際のゲル間の浸透効果が持続しやすい。
【００４６】
水素結合及び／又はイオン結合で結合する結合基としては、カルボキシレート基（⁻ＯＯＣ−）、スルホネート基（−Ｏ_３Ｓ−）、ホスホネート基（（⁻Ｏ）_２ＯＰ−）、カルボキシ基（ＨＯＯＣ−）、スルホ基（ＨＯ_３Ｓ−）、ホスホノ基（（ＨＯ）_２ＯＰ−）、水酸基（−ＯＨ）、オキシアルキレン基（−ＯＡ−）、アミノ基（−ＮＲＨ）、オキシカルボニル基（−ＣＯＯ−）、アミノカルボニル基（−ＣＯＮＨ−）、アルキルオキシ基（−ＯＲ）及びオキシカルボニルアミノ基（−ＮＨＣＯＯ−）等が挙げられる。なお、カッコ内のＲは炭素数１〜３０（好ましくは１〜１０、さらに好ましくは１〜５）のアルキル基（メチル、エチル、ｉ−プロピル、ｔ−ブチル、ウンデシル、オクタデル及びエイコシル等）を表すが、炭素数１〜３０のアルケニル基、アリール基又はアルアルケニル基等であってもよい。また、ＯＡは炭素数１〜８のオキシアルキレン基（オキシメチレン、オキシエチレン、オキシプロピレン、オキシブチレン及びオキシフェニルエチレン等）を表す。
【００４７】
共有結合で結合する結合基は、架橋重合体中のカルボキシ基（ＨＯＯＣ−）又はカルボキシレート基（⁻ＯＯＣ−）と化学反応し結合し得る官能基等が用いられる。例えば、エポキシ基（カルボキシ基と付加反応しエステル結合を生成。）、水酸基（カルボキシ基とエステル化反応しエステル結合を生成。）、アミノ基（カルボキシ基とアミド化反応しアミド結合を生成。）及びイソシアナト基（カルボキシ基と反応し、混合酸無水物を経由しアミド結合を生成。）等が挙げられる。これらの結合基のうち、反応の容易さの観点から、水素結合及び／又はイオン結合で結合する結合基が好ましく、さらに好ましくは水酸基、カルボキシレート基（⁻ＯＯＣ−）、スルホネート基（−Ｏ_３Ｓ−）、ホスホネート基（（⁻Ｏ）_２ＯＰ−）、カルボキシ基（ＨＯＯＣ−）、スルホ基（ＨＯ_３Ｓ−）及びホスホノ基（（ＨＯ）_２ＯＰ−）、特に好ましくはカルボキシレート基、スルホネート基、スルホ基及びカルボキシ基、最も好ましくはカルボキシレート基及びカルボキシ基である。
【００４８】
表面改質剤（Ｍ）中の結合基の数（個）は、水素結合及び／又はイオン結合で結合する結合基の場合、１〜２０が好ましく、さらに好ましくは５〜１８、特に好ましくは７〜１６、最も好ましくは１０〜１５である。また、共有結合で結合する結合基の場合、１〜１０が好ましく、さらに好ましくは１〜５、特に好ましくは１〜３である。結合基の数がこの範囲であるとさらに安定且つ均一に架橋重合体粒子（Ｓ）の表面に（Ｍ）が存在し易くなる傾向がある。
【００４９】
１０〜３０ダイン／ｃｍの表面張力を持つ表面改質剤（Ｍ）としては、炭化水素基を含有する表面改質剤（Ｍ１）、フッ素原子をもつ炭化水素基を含有する表面改質剤（Ｍ２）及びシロキサン構造を含有する表面改質剤（Ｍ３）等が使用できる。これらのうち、シロキサン構造を含有する表面改質剤（Ｍ３）が好ましい。
【００５０】
炭化水素基を含有する表面改質剤（Ｍ１）について説明する。炭化水素基の炭素数は、３〜２０，０００が好ましく、さらに好ましくは８〜１５，０００、特に好ましくは１２〜１０，０００である。炭化水素基としては、脂肪族炭化水素基及び芳香族炭化水素基等が使用できる。脂肪族炭化水素としては、炭素数３〜２０，０００（好ましくは８〜１５，０００、さらに好ましくは１２〜１０，０００）のアルキル基、炭素数３〜２０，０００（好ましくは８〜１５，０００、さらに好ましくは１２〜１０，０００）のアルキレン基、炭素数３〜２０，０００（好ましくは８〜１５，０００、さらに好ましくは１２〜１０，０００）のアルケニル基、炭素数３〜２０，０００（好ましくは８〜１５，０００、さらに好ましくは１２〜１０，０００）のアルケニレン基等が用いられる。芳香族炭化水素基としては、炭素数６〜２０，０００（好ましくは８〜１５，０００、さらに好ましくは１０〜１０，０００）のアリール基、及び炭素数６〜３０，０００（好ましくは８〜１５，０００、さらに好ましくは１０〜１０，０００）のアリーレン基等が用いられる。
【００５１】
アルキル基としては、例えば、プロピル基、ブチル基、ペンチル基、ヘキシル基、オクチル基、ドデシル基、ステアリル基、エイコシル基及びトリアコンチル基等が挙げられる。アルキレン基としては、例えば、プロピレン基、ブチレン基、ヘキシレン基、オクチレン基、ドデシレン基、オクタデシレン基、エイコシレン基及びポリエチレン（炭素数４〜２０，０００、好ましくは８〜１５，０００、さらに好ましくは１２〜１０，０００）やポリプロピレン（炭素数６〜２０，０００、好ましくは９〜１５，０００、さらに好ましくは１２〜１０，０００）から水素原子を２個除いた炭化水素基等が挙げられる。アルケニル基としては、例えば、プロペニル基、ブテニル基、ペンテニル基、ヘキセニル基、オクテニル基、ドデセニル基、オクタデセニル基、エイコセニル基及びトリアコンテニル基等が挙げられる。アルケニレン基としては、例えば、プロペニレン基、ブテニレン基、ヘキセニレン基、オクテニレン基、ドデセニレン基、オクタデセニレン基、エイコセニレン基、トリアコンテニレン基及びポリエチレンの熱減成物（炭素数４〜２００００、好ましくは８〜１５，０００、さらに好ましくは１２〜１０，０００）やポリプロピレンの熱減成物（炭素数６〜２００００、好ましくは９〜１５，０００、さらに好ましくは１２〜１０，０００）から水素原子を２個除いた炭化水素基等が挙げられる。なお、熱減性物は、ポリエチレンやポリプロピレンを加熱処理することにより不飽和二重結合を導入させたものである。
【００５２】
アリール基としては、例えば、フェニル基、ベンジル基、エチルフェニル基、テトラデシルフェニル基、ノニルフェニル基、ジメチルフェニル基、ジエチルフェニル基、ジヘプチルフェニル基、ジノニルフェニル基、ジノニルフェニルフェニル基、トリル基、メシチル基、クメニル基、トリル基、キシリル基、ナフチル基、アントリル基及びフェナントリル基等が挙げられる。
アリーレン基としては、例えば、フェニレン基、エチルフェニレン基、テトラデシルフェニレン基、ノニルフェニレン基、ジメチルフェニレン基、ジエチルフェニレン基、ジヘプチルフェニレン基、ジノニルフェニレン基、ジノニルフェニルフェニレン基、トリレン基、メシチレン基、クメニレン基、トリレン基、キシリレン基、ナフチレン基、アントリレン基、フェナントリレン基及びビスフェノール（ビスフェノール、ビスフェノールＡ及びビスフェノールＦ等）のフェノール性水酸基を除いた残基等が挙げられる。これらのうち、表面張力がより小さいという観点から、脂肪族炭化水素基が好ましく、さらに好ましくはアルキル基、アルキレン基、アルケニル基及びアルケニレン基、特に好ましくはペンチル基、ヘキシル基、オクチル基、ドデシル基、ステアリル基、トリアコンチル基、オクチレン基、ドデシレン基、ポリエチレンやポリプロピレンから水素原子を２個除いた炭化水素基、ポリエチレンの熱減成物やポリプロピレンの熱減成物から水素原子を２個除いた炭化水素基、特にさらに好ましくはオクチル基、ドデシル基、ステアリル基、トリアコンチル基、ドデシレン基、ポリエチレンやポリプロピレンから水素原子を２個除いた炭化水素基、ポリエチレンの熱減成物やポリプロピレンの熱減成物から水素原子を２個除いた炭化水素基、最も好ましくはドデシル基、ステアリル基、トリアコンチル基、ポリエチレンやポリプロピレンから水素原子を２個除いた炭化水素基、ポリエチレンの熱減成物やポリプロピレンの熱減成物から水素原子を２個除いた炭化水素基である。
【００５３】
炭化水素基を含有する表面改質剤（Ｍ１）としては、以下の（１）〜（１３）等が含まれる。
（１）結合基としてカルボキシレート基を有するものとしては、オクタンカルボン酸ナトリウム、オクタンジカルボン酸ナトリウム、ウンデカン酸ナトリウム、オクタデカン酸ナトリウム及びトリアコンタンカルボン酸ナトリウム等が挙げられる。
（２）結合基としてスルホネート基を有するものとしては、オクタンスルホン酸ナトリウム及びドデシルベンゼンスルホン酸ナトリウム等が挙げられる。
（３）結合基としてホスホネート基を有するものとしては、トリアコンタンホスホン酸ナトリウム等が挙げられる。
（４）結合基としてカルボキシ基を有するものとしては、例えば、オクタンカルボン酸、オクタンジカルボン酸、ウンデカン酸、オクタデカン酸及びトリアコンタンカルボン酸等が挙げられる。
（５）結合基としてスルホ基又はホスホノ基を有するものとしては、例えば、オクチルスルホン酸、ドデシルベンゼンスルホン酸及びトリアコンチルホスホン酸等が挙げられる。
（６）結合基として水酸基を有するもの（オキシアルキレン基を持たないもの）としては、オクチルアルコール、オクチレンジオール、トリアコンチルアルコール、オクテニルアルコール、トリアコンテニルアルコール及びオクテニレンジオール等が挙げられる。
（７）結合基としてオキシアルキレン基を有するものとしては、オクチルアルコールエチレンオキサイド（１〜２０個）付加物、オクチレンジオールエチレンオキサイド（１〜２０個）付加物、トリアコンチルアルコールエチレンオキサイド（１〜２０個）付加物、オクテニルアルコールエチレンオキサイド（１〜２０個）付加物、トリアコンテニルアルコールエチレンオキサイド（１〜２０個）付加物及びオクテニレンジオールエチレンオキサイド（１〜２０個）付加物等の水酸基を有するもの、並びにこれらの末端水酸基がアルキル基の炭素数１〜４のアルキルオキシ基又はアルキルカルボキシル基に変換されたもの等のアルキルオキシ基を有するもの等が挙げられる。
（８）結合基としてアミノ基を有するものとしては、例えば、オクチルアミン、ジオクチルアミン、トリアコンチルアミン、トリアコンチルメチルアミン、オクチレンジアミン、オクチルエチルアミン及びノニルエチルアミン等が挙げられる。
（９）結合基としてオキシカルボニル基を有するものとしては、プロパンカルボン酸オクチルエステル、プロパンカルボン酸ノニルエステル、オクタンカルボン酸エチルエステル及びノナンカルボン酸エチルエステル等が挙げられる。（１０）結合基としてアミノカルボニル基を有するものとしては、Ｎ−オクチルプロパンカルボン酸アミド、Ｎ−ノニルプロパンカルボン酸アミド、Ｎ−プロピルオクタン酸アミド及びＮ−エチルウンデカン酸アミド等が挙げられる。
（１１）結合基としてオキシカルボニルアミノ基を有するものとしては、オクチルオキシカルボニルアミノエタン、ノニルオキシカルボニルアミノエタン、オクチルアミノカルボニルオキシエタン及びノニルアミノカルボニルオキシエタン等が挙げられる。
（１２）結合基としてエポキシ基を有するものとしては、オクチルグリシジルエーテル、オクチレンジグリシジルエーテル及びトリアコンチルグリシジルエーテル等が挙げる。
（１３）結合基としてイソシアナト基を有するものとしては、オクチルイソシアナート及びノニルイソシアナート等が挙げられる。
【００５４】
これらの（１）〜（１３）のうち、（１）結合基としてカルボキシレート基を有するもの、（２）結合基としてスルホネート基を有するもの、（４）結合基としてカルボキシ基を有するもの、（５）結合基としてスルホ基又はホスホノ基を有するもの及び（８）結合基としてアミノ基を有するものが好ましく、さらに好ましくは（１）、（２）及び（８）、特に好ましくは（８）である。
【００５５】
フッ素原子をもつ炭化水素基を含有する表面改質剤（Ｍ２）について説明する。炭化水素基のフッ素原子数は、３〜６０が好ましく、さらに好ましくは１０〜５０、特に好ましくは１５〜４０である。また、炭素数は、１〜３０が好ましく、さらに好ましくは５〜２５、特に好ましくは８〜２０である。フッ素原子をもつ炭化水素基としては、フッ素含有脂肪族炭化水素基及びフッ素含有芳香族炭化水素基等が使用できる。
【００５６】
フッ素含有脂肪族炭化水素基としては、パーフルオロアルキル基（炭素数１〜３０、好ましくは５〜２５、さらに好ましくは８〜２０）、パーフルオロアルキル（炭素数１〜３０、好ましくは５〜２５、さらに好ましくは８〜２０）−アルキレン基（炭素数１〜２０、好ましくは１〜１０、さらに好ましくは２〜８）、パーフルオロアルキレン基（炭素数１〜３０、好ましくは５〜２５、さらに好ましくは８〜２０）、パーフルオロアルケニル基（炭素数３〜３０）、パーフルオロアルケニレン基（炭素数３〜３０）等が用いられる。
フッ素含有芳香族炭化水素基としては、パーフルオロアリール基（炭素数６〜３０）及びパーフルオロアリーレン基（炭素数６〜３０）等が用いられる。
【００５７】
パーフルオロアルキル基としては、トリフルオロメチル基、ペンタフルオロエチル基、ペンタフルオロプロピル基（ペンタフルオロエチルメチル基等）、ヘプタフルオロプロピル基、ヘプタフルオロブチル基（ヘプタフルオロメチル基等）、ノナフルオロヘキシル基（ノナフルオロブチルエチル基等）、トリデカフルオロオクチル基（トリデカフルオロヘキシルエチル基等）及びヘプタデカフルオロドデシル基（ヘプタデカフルオロオクチルブチル基等）等が挙げられる。パーフルオロアルキルアルキレン基としては、例えば、ペンタフルオロエチル−エチレン基、ヘプタフルオロプロピル−エチレン基、ノナフルオロブチル−エチレン基、トリデカフルオロヘキシル−エチレン基及びヘプタデカフルオロオクチル−エチレン基等が挙げられる。パーフルオロアルキレン基としては、例えば、ジフルオロメチレン基、テトラフルオロエチレン基、ヘキサフルオロプロピレン基、オクタフルオロブチレン基、ドデカフルオロヘキシレン基、ヘキサデカフルオロオクチレン基及びテトラコサフルオロドデシレン基等が挙げられる。パーフルオロアルケニル基としては、例えば、ペンタフルオロプロペニル基、ヘプタフルオロブテニル基、ノナフルオロペンテニル基、ウンデカフルオロヘキセニル基、ペンタデカオクテニル基、トリコサドデセニル基及びノナペンタコンタフルオロトリアコンテニル基等等が挙げられる。
パーフルオロアルケニレン基としては、例えばテトラフルオロプロペニレン基、ヘキサフルオロブテニレン基、デカフルオロヘキセニレン基、テトラデカフルオロオクテニレン基、ドコサフルオロドデセニレン基及びオクタペンタコンタフルオロトリアコンテニレン基等が挙げられる。パーフルオロアリール基としては、例えば、ペンタフルオロフェニル基、ヘプタフルオロメチルフェニル基、ノナフルオロエチルフェニル基、トリトリアコンタフルオロテトラデシルフェニル基、ノナフルオロジメチルフェニル基、トリデカフルオロジエチルフェニル基及びトリトリアコンタフルオロジヘプチルフェニル基等が挙げられる。パーフルオロアリーレン基としては、例えば、テトラフルオロフェニレン基、ヘキサフルオロメチルフェニレン基、オクタフルオロエチルフェニレン基、ジトリアコンタフルオロテトラデシルフェニレン基、オクタフルオロジメチルフェニレン基、ドデカフルオロジエチルフェニレン基及びジトリアコンタフルオロジヘプチルフェニレン基等が挙げられる。
【００５８】
これらのうち、表面張力の観点から、フッ素含有脂肪族炭化水素基が好ましし、さらに好ましくはパーフルオロアルキル基、パーフルオロアルキル−アルキレン基及びパーフルオロアルキレン基、特に好ましくはパーフルオロアルキル基及びパーフルオロアルキルアルキレン基、最も好ましくはパーフルオロアルキルである。パーフルオロアルキル基の中では、ヘプタフルオロプロピル基、ヘプタフルオロブチル基、ノナフルオロヘキシル基、トリデカフルオロオクチル基及びヘプタデカフルオロドデシル基が好ましく、さらに好ましくは、ヘプタフルオロプロピル基及びヘプタフルオロブチル基、特に好ましくはヘプタフルオロブチルパーフルオロアルキル基である。
【００５９】
フッ素原子をもつ炭化水素基をを含有する表面改質剤（Ｍ２）としては、以下の（１４）〜（２６）等が含まれる。
（１４）結合基としてカルボキシレート基を有するものとしては、ノナフルオロヘキサンカルボン酸ナトリウム及びドデカフルオロヘキサンジカルボン酸ジナトリウム等が挙げられる。
（１５）結合基としてスルホネート基を有するものとしては、ノナフルオロヘキサンスルホン酸酸ナトリウム及びドデカフルオロヘキサンジスルホン酸ジナトリウム等が挙げられる。
（１６）結合基としてホスホネート基を有するものとしては、ノナフルオロヘキサンホスホン酸ナトリウム及びドデカフルオロヘキサンジホスホン酸ジナトリウム等が挙げられる。
（１７）結合基としてカルボキシ基を有するものとしては、ノナフルオロヘキサンカルボン酸及びドデカフルオロヘキサンジカルボン酸等が挙げられる。
（１８）結合基としてスルホ基又はホスホノ基を有するものとしては、ノナフルオロヘキシルスルホン酸及びノナフルオロヘキシルホスホン酸等が挙げられる。
（１９）結合基として水酸基を有するものとしては、ノナフルオロヘキサノール及びドデカフルオロヘキサンノール等が挙げられる。
（２０）結合基としてアミノ基を有するものとしては、ノナフルオロヘキシルアミン、ジ（ノナフルオロヘキシル）アミン、ドデカフルオロヘキシレンジアミン、テトラコサフルオロドデシレンジアミン、デカフルオロヘキセニルアミン、ノナフルオロヘキシルエチルアミン及びドデカフルオロヘキシルエチルアミン等が挙げられる。
（２１）結合基としてオキシカルボニル基を有するものとしては、ノナフルオロヘキサンカルボン酸メチル、ドデカフルオロヘキサンジカルボン酸ジメチル、酢酸ノナフルオロヘキシル及び酢酸ドデカフルオロヘキシル等が挙げられる。
（２２）結合基としてアミノカルボニル基を有するものとしては、Ｎ−メチルノナフルオロヘキサン酸アミド、Ｎ−メチルドデカフルオロヘキサン酸アミド、Ｎ−ヘキシルトリフルオロアセトアミド及びＮ−メチルトリフルオロアセトアミド等が挙げられる。
（２３）結合基としてアルキルオキシ基を有するものとしては、ノナフルオロヘキシルエチルエーテル、２−ペンタフルオロエチルヘキシルメチルエーテル
ドデカフルオロヘキシルメチルエーテル及びドデカフルオロヘキシルエチルエーテル等が挙げられる。
（２４）結合基としてアミノカルボニルオキシ基を有するものとしては、ノナフルオロヘキシルオキシカルボニルアミノエタン及びドデカフルオロヘキシルオキシカルボニルアミノエタン等が挙げられる。
（２５）結合基としてエポキシ基を有するものとしては、ノナフルオロヘキシルグリシジルエーテル及びドデカフルオロヘキレンジグリシジルエーテル等が挙げられる。
（２６）結合基としてイソシアナト基を有するものとしては、イソシアナトノナフルオロヘキサン及びイソシアナトドデカフルオロヘキサン等が挙げられる。
【００６０】
これらの（１４）〜（２６）のうち、（１４）結合基としてカルボキシレート基を有するもの、（１５）結合基としてスルホネート基を有するもの、（１７）結合基としてカルボキシ基を有するもの、（１８）結合基としてスルホ基又はホスホノ基を有するもの及び（２０）結合基としてアミノ基を有するものが好ましく、さらに好ましくは（１４）、（１５）及び（２０）、特に好ましくは（２０）である。
【００６１】
シロキサン構造を含有する表面改質剤（Ｍ３）について説明する。
シロキサン構造を含有する表面改質剤（Ｍ３）としては、ポリエーテル変性シリコーンオイル（ポリエチレンオキサイド変性シリコーン及びポリエチレンオキサイド・ポリプロピレンオキサイド変性シリコーン等）、カルボキシル変性シリコーンオイル、アルキル変性シリコーンオイル、エポキシ変性シリコーンオイル、アミノ変性シリコーンオイル及びアルコキシ変性シリコーンオイル等が含まれる。ポリエーテル変性シリコーンオイルとしては、ポリエチレンオキサイド変性シリコーン及びポリエチレンオキサイド・ポリプロピレンオキサイド変性シリコーン等が使用でき、例えば、信越化学工業社製の商品：ＫＦ−３５１，ＫＦ−３５２、ＫＦ−３５３及びＫＦ−６１５Ａ、並びに東レ・ダウコーニング・シリコーン社製の商品：ＢＹ−１６−００４、ＳＨ３７４６及びＳＦ８４１０等が挙げられる。カルボキシル変性シリコーンオイルとしては、信越化学工業社製の商品：Ｘ−２２−１６２Ｃ、Ｘ−２２−３７０１Ｅ及びＸ−２２−３７１０、並びに東レ・ダウコーニング・シリコーン社製の商品：ＢＹ−１６−７５０及びＳＦ８４１８等が挙げられる。アルキル変性シリコーンオイルとしては、信越化学工業社製の商品：ＫＦ−４１２、ＫＦ−４１３及びＫＦ−４１４、並びに東レ・ダウコーニング・シリコーン社製の商品：ＳＨ２０３、ＳＨ２３０及びＳＦ８４１６等が挙げられる。
エポキシ変性シリコーンオイルとしては、信越化学工業社製の商品：ＫＦ−１０５、Ｘ−２２−１６３Ａ、Ｘ−２２−１６３Ｃ、ＫＦ−１００１及びＸ−２２−１６９Ｂ、並びに東レ・ダウコーニング・シリコーン社製の商品：ＢＹ１６−８５５Ｄ、ＳＦ８４１１、ＢＹ１６−８３９及びＳＦ８４２１等が挙げられる。アミノ変性シリコーンオイルとしては、信越化学工業社製の商品：ＫＦ−８８０、ＫＦ−８８５、ＫＦ−８６７、ＫＦ−８００３及びＫＦ−８００４、並びに東レ・ダウコーニング・シリコーン社製の商品：ＢＹ−１６−８５３Ｃ、ＢＹ１６−２０８、ＢＹ１６−２０９、ＢＹ１６−８５０及びＢＹ１６−８７２等が挙げられる。アルコキシ変性シリコーンオイルとしては、信越化学工業社製の商品：ＫＦ−８５７、ＫＦ−８６２及びＫＦ−８００１等が挙げられる。これらの（Ｍ３）のうち、入手コスト等の観点から、ポリエーテル変性シリコーンオイルが好ましく、さらに好ましくはポリエチレンオキサイド変性シリコーンである。
【００６２】
表面改質剤（Ｍ）の２５℃における粘度（ｃＳｔ）は、架橋重合体粒子（Ｓ）との均一混合性、または（Ｓ）の内部への浸透性等の観点から、１０〜２，０００が好ましく、さらに好ましくは１５〜１，５００、特に好ましくは２０〜１０００である。すなわち、表面改質剤（Ｍ）の２５℃における粘度（ｃＳｔ）は、１０以上が好ましく、さらに好ましくは１５以上、特に好ましくは２０以上であり、また２，０００以下が好ましく、さらに好ましくは１，５００以下、特に好ましくは１０００以下である。
【００６３】
これらの表面改質剤（Ｍ）は二種以上を併用することもできる。また、表面改質剤（Ｍ）は、水又は揮発性溶剤に、溶解又は乳化した形態でも使用できる。揮発性溶剤としては、２０℃での蒸気圧が１７．５〜７００ｍｍＨｇのものが好ましく、さらに好ましくは２０〜６００ｍｍＨｇ、特に好ましくは３０〜５００ｍｍＨｇのものである。すなわち、揮発性溶剤の２０℃での蒸気圧（ｍｍＨｇ）は、１７．５以上が好ましく、さらに好ましくは２０以上、特に好ましくは３０以上のものであり、また７００以下が好ましく、さらに好ましくは６００以下、特に好ましくは５００以下である。揮発性溶剤としては、アルコール（メタノール、エタノール及びイソプロピルアルコール等）、炭化水素（ヘキサン、シクロヘキサン及びトルエン等）、エーテル（ジエチルエーテル及びテトラヒドロフラン等）、ケトン（アセトン及びメチルエチルケトン等）、及びエステル（酢酸エチル、酢酸イソプロピル及び炭酸ジエチル等）等が挙げられる。水又は揮発性溶剤を使用する場合、これらの使用量（重量％）は、（Ｂ）の重量に基づいて、１〜９００が好ましく、さらに好ましくは５〜７００、特に好ましくは１０〜４００である。すなわち、この場合、これらの使用量（重量％）は、（Ｂ）の重量に基づいて、１以上が好ましく、さらに好ましくは５以上、特に好ましくは１０以上であり、また９００以下が好ましく、さらに好ましくは７００以下、特に好ましくは４００以下である。水及び揮発性溶剤を使用する場合、水の使用量（重量％）は、水及び揮発性溶剤の重量に基づいて、５０〜９８が好ましく、さらに好ましくは６０〜９５、特に好ましくは７０〜９０である。すなわち、５０以上が好ましく、さらに好ましくは６０以上、特に好ましくは７０以上であり、また９８以下が好ましく、さらに好ましくは９５以下、特に好ましくは９０以下である。
【００６４】
表面改質剤（Ｍ）のＨＬＢは、７〜１８が好ましく、さらに好ましくは８〜１８、特に好ましくは１０〜１８である。なお、ＨＬＢは、親水性−疎水性バランス（ＨＬＢ）値を意味し、小田法（界面活性剤の合成と其応用、５０１頁、槇書店、小田、寺村；新・界面活性剤入門、１９７頁、藤本武彦、三洋化成工業株式会社発行）により求められる。
【００６５】
表面改質剤（Ｍ）の使用量（重量％）は、架橋重合体粒子（Ｓ）の重量に基づいて、０．００１〜３が好ましく、さらに好ましくは０．００５〜２、特に好ましくは０．０７〜１．５、最も好ましくは０．１〜１．０である。すなわち、表面改質剤（Ｍ）の使用量（重量％）は、架橋重合体粒子（Ｓ）の重量に基づいて、０．００１以上が好ましく、さらに好ましくは０．００５以上、特に好ましくは０．０７以上、最も好ましくは０．１以上であり、また、３以下が好ましく、さらに好ましくは２以下、特に好ましくは１．５以下、最も好ましくは１．０以下である。この範囲未満では表面改質剤（Ｍ）で処理されていない吸水性重合体粒子と効果上の差が現れにくく、この範囲を越えると粉体流動性の面で好ましくない傾向にある。
【００６６】
吸水性重合体粒子（Ｘ）は、架橋重合体粒子（Ｓ）と表面改質剤（Ｍ）とからなればよいが、架橋重合体粒子（Ｓ）の表面近傍に（Ｍ）が存在することが好ましく、架橋重合体粒子（Ｓ）の重合後、架橋重合体粒子（Ｓ）と（Ｍ）とを混合・処理することが望ましい。水溶液重合により架橋重合体粒子（Ｓ）を得るとき、表面改質剤（Ｍ）を混合・処理するタイミングとしては特に制限はないが、重合工程中、重合工程直後、含水樹脂（ＷＡ）の破砕（ミンチ）中、表面架橋処理工程直前、表面架橋処理工程中、表面架橋処理工程直後及び乾燥工程中等が挙げられる。これらのうち、架橋重合体粒子（Ｓ）の粒子表面を均一に処理する観点から、重合工程直後、含水樹脂（ＷＡ）の破砕（ミンチ）工程中、表面架橋処理工程直前、表面架橋処理工程中、表面架橋処理工程直後及び乾燥工程中が好ましく、表面改質剤（Ｍ）中の結合基と架橋重合体粒子（Ｓ）との結合しやすさの観点から、さらに好ましくは重合工程直後、含水樹脂（ＷＡ）の破砕（ミンチ）中、表面架橋処理工程直前、表面架橋処理工程中及び表面架橋処理工程直後、特に好ましくは表面架橋処理工程直前、表面架橋処理工程中及び表面架橋処理工程直後である。
【００６７】
逆相懸濁重合により架橋重合体粒子（Ｓ）を得るとき、表面改質剤（Ｍ）を混合・処理するタイミングとしては特に制限はないが、重合工程中、重合工程直後、脱水工程中（水分１０重量％前後まで脱水する工程中）、脱水工程直後、重合で得られた吸水性樹脂粒子（Ｓ）と重合に用いた有機溶剤とを分離する工程中、表面架橋処理工程直前、表面架橋処理工程中、表面架橋処理工程直後及び乾燥工程中（１０重量％以下まで乾燥する工程）等が挙げられる。これらのうち、架橋重合体粒子（Ｓ）の粒子表面を均一に処理する観点から、重合工程直後、脱水工程中、脱水工程直後、重合で得られた吸水性樹脂粒子（Ｓ）と重合に用いた有機溶剤とを分離する工程中、表面架橋処理工程直前、表面架橋処理工程中、表面架橋処理工程直後及び乾燥工程中が好ましく、表面改質剤（Ｍ）中の結合基と架橋重合体粒子（Ｓ）との結合しやすさの観点から、さらに好ましくは重合工程直後、脱水工程中、脱水工程直後、重合で得られた吸水性樹脂粒子（Ｓ）と重合に用いた有機溶剤とを分離する工程中、表面架橋処理工程直前、表面架橋処理工程中及び表面架橋処理工程直後、特に好ましくは脱水工程中、表面架橋処理工程直前、表面架橋処理工程中及び表面架橋処理工程直後である。
【００６８】
すなわち、架橋重合体粒子（Ｓ）と表面改質剤（Ｍ）とを混合・処理する工程としては何れの段階でもよいが、含水樹脂から水の除去前、除去中又は除去後に行うのが好ましく、表面改質剤（Ｍ）中の結合基と架橋重合体粒子（Ｓ）との結合しやすさの観点から、さらに好ましくは含水樹脂の水分が１０重量％以上の段階、すなわち、水の除去前又は除去中の段階である。
【００６９】
架橋重合体粒子（Ｓ）と表面改質剤（Ｍ）とを混合・処理する方法としては、あらかじめ（Ｍ）を高濃度（例えば架橋重合体の粒子に対し５〜２０重量％）室温で架橋重合体粒子（Ｓ）に添加、１０分以上混合してマスターバッチを作成しておき、（Ｍ）として所定の添加量になる様にマスターバッチを架橋重合体粒子（Ｓ）に室温で添加、１０分以上混合・処理する方法、架橋重合体粒子（Ｓ）を撹拌しながら（Ｍ）を室温で添加、又はスプレーして混合・処理する方法等が挙げられる。架橋重合体粒子（Ｓ）と表面改質剤（Ｍ）との混合・処理する工業的な装置としては、特に制限はないが、例えば、コニカルブレンダー、ナウターミキサー、双腕型ニーダー、Ｖ型混合機、流動層式混合機、タービュライザー、スクリュー式のラインブレンド装置、リボンミキサー及びモルタルミキサー等の機械的混合装置が好適に用いられる。
【００７０】
表面改質剤（Ｍ）の粘度が１，０００〜２，０００ｃＳｔ又はこれ以上の場合、架橋重合体粒子（Ｓ）及び／又は表面改質剤（Ｍ）を加熱（３０〜２００℃が好ましく、さらに好ましくは４０〜１６０℃、特に好ましくは５０〜１２０℃）してから架橋重合体粒子（Ｓ）と（Ｍ）とを混合・処理することができる。すなわち、この場合、架橋重合体粒子（Ｓ）及び／又は表面改質剤（Ｍ）の加熱温度（℃）は、３０以上が好ましく、さらに好ましくは４０以上、特に好ましくは５０以上であり、また２００以下が好ましく、さらに好ましくは１６０以下、特に好ましくは１２０以下である。
【００７１】
架橋重合体粒子（Ｓ）が表面架橋剤でその粒子の表面近傍を表面架橋処理された架橋重合体粒子である場合は、表面架橋剤（またはこの溶液）の中に（Ｍ）を添加しておいてもよい。表面改質剤（Ｍ）の結合基の結合様式が主に共有結合の場合、架橋重合体粒子（Ｓ）と（Ｍ）とを混合した後、加熱工程を設けて加熱反応を行うことが好ましい。加熱温度（℃）は、８０〜２００が好ましく、さらに好ましくは９０〜１６０、特に好ましくは１００〜１４０である。すなわち、加熱温度（℃）は、８０以上が好ましく、さらに好ましくは９０以上、特に好ましくは１００以上であり、また２００以下が好ましく、さらに好ましくは１６０以下、特に好ましくは１４０以下である。反応時間（分）は、反応温度により変化させることができるが、３〜６０が好ましく、さらに好ましくは５〜４０、特に好ましくは８〜３０である。すなわち、反応時間（分）は、３以上が好ましく、さらに好ましくは５以上、特に好ましくは８以上であり、また６０以下が好ましく、さらに好ましくは４０以下、特に好ましくは３０以下である。表面改質剤（Ｍ）の結合基の結合様式が主に水素結合又は主にイオン結合の場合、架橋重合体と（Ｍ）とを混合した後、特に加熱する工程を設ける必要はない。
【００７２】
表面改質剤（Ｎ）の表面張力（ダイン／ｃｍ）は、４０〜８０が好ましく、さらに好ましくは４０〜７５、特に好ましくは４０〜７０、最も好ましくは４０〜６５である。表面改質剤（Ｎ）は、架橋重合体粒子（Ｓ）の表面に付着（物理吸着）又は固着（化学結合）した状態となることにより、架橋重合体粒子（Ｓ）の表面を改質するためのものである。表面改質剤（Ｎ）は、架橋重合体粒子（Ｓ）と化学結合し得る結合基を有するものが好ましく、結合様式としては、水素結合、イオン結合及び共有結合等が挙げられる。なお、表面改質剤（Ｎ）は１種の結合基を有するものだけではなく、２種以上の結合基を有してもよい。架橋重合体粒子（Ｓ）と化学結合し得る結合基を有すると、架橋重合体粒子（Ｓ）の表面に安定して表面改質剤（Ｎ）が存在できるため、吸水時のゲル間の浸透効果が持続する。
【００７３】
結合基としては、表面改質剤（Ｍ）の結合基と同様であり、これらの結合基のうち、反応の容易さ等の観点から、水素結合で結合する結合基及びイオン結合で結合する結合基が好ましく、さらに好ましくは水酸基、カルボキシレート（⁻ＯＯＣ−）、スルホネート（−Ｏ_３Ｓ−）及びホスホネート（（⁻Ｏ）_２ＯＰ−）等である。
【００７４】
表面改質剤（Ｎ）中の結合基の数（個）は、１〜２０が好ましく、さらに好ましくは５〜１８、特に好ましくは７〜１６、最も好ましくは１０〜１５である。結合基の数がこの範囲であるとさらに安定且つ均一に架橋重合体粒子（Ｓ）の表面に表面改質（Ｎ）が存在し易くなる傾向がある。
【００７５】
表面改質剤（Ｎ）としては、ポリオキシアルキレン基を有する表面改質剤（Ｎ１）、ポリカチオン（Ｎ２）及びポリアニオン（Ｎ３）等が含まれる。これらのうち、ポリオキシアルキレン基を有する表面改質剤（Ｎ１）が好ましい。
【００７６】
ポリオキシアルキレン基としては、ポリオキシエチレン基、ポリオキシエチレンポリオキシプロピレン（ブロック共重合）基及びポリオキシテトラメチレン基等が挙げられる。これらのポリオキシアルキレン基の重合度は３〜１０００であり、好ましくは５〜１００、さらに好ましくは１０〜５０、特に好ましくは２０〜２５である。すなわち、この重合度は３以上であり、好ましくは５以上、さらに好ましくは１０以上、特に好ましくは２０以上であり、また１０００以下であり、好ましくは１００以下、さらに好ましくは５０以下、特に好ましくは２５以下である。
【００７７】
ポリオキシアルキレン基を有する表面改質剤（Ｎ１）としては、以下の（２７）〜（３７）等が含まれる。
（２７）結合基としてカルボキシレート基を有するものとしては、ポリ（オキシエチレン）プロピオン酸ナトリウム及びポリ（オキシエチレン）酢酸ナトリウム等が挙げられる。
（２８）結合基としてスルホネート基を有するものとしては、ポリ（オキシエチレン）スルホン酸ナトリウム等が挙げられる。
（２９）結合基としてホスホネート基を有するものとしては、ポリ（オキシエチレン）ホスホン酸ナトリウム等が挙げられる。
（３０）結合基としてカルボキシ基を有するものとしては、ポリ（オキシエチレン）プロピオン酸及びポリ（オキシエチレン）酢酸等が挙げられる。
（３１）結合基としてスルホ基又はホスホノ基を有するものとしては、ポリ（オキシエチレン）スルホン酸及びポリ（オキシエチレン）ホスホン酸等が挙げられる。
（３２）結合基としてアミノ基を有するものとしては、ポリ（オキシエチレン）エチルアミン、ビス（ポリ（オキシエチレン））エチルアミン及びトリス（ポリ（オキシエチレン））エチルアミン等が挙げられる。
（３３）結合基としてカルボニルオキシ基を有するものとしては、ポリ（オキシエチレン）カルボニルオキシエタン及びポリ（オキシエチレン）カルボニルオキシエタン等が挙げられる。
（３４）結合基としてアミノカルボニル基を有するものとしては、Ｎ−ポリオキシエチレン−Ｎ−エチルプロパンカルボン酸アミド及びＮ−ポリオキシエチレン−Ｎ−プロピルプロパン酸アミド等が挙げられる。
（３５）結合基としてアルキルオキシ基を有するものとしては、ポリ（オキシエチレン）ジメチルエーテル、ポリオキシエチレンジエチルエーテル、メチルオキシポリ（オキシエチレン）酢酸エステル及びメチルオキシポリ（オキシエチレン）ウンデシルエーテル等が挙げられる。
（３６）結合基としてエポキシ基を有するものとしては、ポリオキシエチレンモノグリシジルエーテル、メチルオキシポリオキシエチレングリシジルエーテル及びポリオキシエチレンジグリシジルエーテル等が挙げる。
（３７）結合基としてイソシアナト基を有するものとしては、ポリ（エチレンオキシ）エチルイソシアナート等が挙げられる。
【００７８】
これらの（２７）〜（３７）のうち好ましくは、（２７）結合基としてカルボキシレート基を有するもの、（２８）結合基としてスルホネート基を有するもの、（２９）結合基としてカルボキシ基を有するもの、（３０）結合基としてスルホ基又はホスホノ基を有するもの及び（３１）結合基としてアミノ基を有するものが好ましく、さらに好ましくは（２７）、（２８）及び（３１）、特に好ましくは（３１）である。
【００７９】
ポリカチオン（Ｎ２）としては、第４級アンモニオ基を有する重合体及びポリメチレンポリアミンの４級塩等が含まれる。第４級アンモニオ基を有する重合体としては、第４級アンモニオ基含有ラジカル重合性モノマーを必須構成単位としてなる構造を有する重合体等が含まれる。第４級アンモニオ基含有ラジカル重合性モノマーとしては、炭素数６〜３０のアンモニウム塩等が使用でき、トリメチルプロペニルアンモニウム・ヒドロキシド、トリメチルアミノエチル（メタ）アクリレート・クロライド、メチルジエチルアミノエチル（メタ）アクリレート・メトサルフェート、トリメチルアミノエチル（メタ）アクリルアミド・クロライド及びジエチルベンジルアミノエチル（メタ）アクリルアミド・クロライド等が挙げられる。第４級アンモニオ基を有する重合体の重量平均分子量は、５００以上が好ましく、さらに好ましくは５０００以上、特に好ましくは１００００以上であり、また、１００００００以下が好ましく、さらに好ましくは５００００以下、特に好ましくは２００００以下である。共重合させるラジカル重合性モノマーとしては特に限定はされないが、（メタ）アクリルアミド、Ｎ−アルキル（炭素数１〜８）（メタ）アクリルアミド（Ｎ−メチルアクリルアミド等）、Ｎ，Ｎ−ジアルキル（炭素数１〜８）（メタ）アクリルアミド（Ｎ，Ｎ−ジメチルアクリルアミド及びＮ，Ｎ−ジ−ｎ−又はｉ−プロピルアクリルアミド等）及びＮ−ヒドロキシアルキル（炭素数１〜８）（メタ）アクリルアミド等が挙げられる。ポリメチレンポリアミンの４級塩としては、Ｎ，Ｎ，，Ｎ’，Ｎ’−テトラメチルテトラメチレンジアミン・ジクロライド等が挙げられる。これらのうち、第４級アンモニオ基を有する重合体が好ましく、さらに好ましくはトリメチルプロペニルアンモニウム・ヒドロキシド又はトリメチルアミノエチル（メタ）アクリレート・クロライドを用いた第４級アンモニオ基を有する重合体である。
【００８０】
ポリアニオン（Ｎ３）としては、カルボキシレートを有するラジカル重合性モノマーのラジカル重合体、スルホネートを有するラジカル重合性モノマーのラジカル重合体、及びホスホネートを有するラジカル重合性モノマーのラジカル重合体等が含まれる。ポリアニオンの重量平均分子量は、５００以上が好ましく、さらに好ましくは５０００以上、特に好ましくは１００００以上であり、また、１００００００以下が好ましく、さらに好ましくは５００００以下、特に好ましくは２００００以下である。カルボキシレートを有するラジカル重合性モノマモノマーとしては、炭素数３〜１０の不飽和モノカルボン酸塩｛（メタ）アクリル酸ナトリウム、クロトン酸ナトリウム及び桂皮酸カリウム等｝及び炭素数４〜１０の不飽和ジカルボン酸塩｛マレイン酸ナトリウム、フマル酸ナトリウム、シトラコン酸カリウム及びイタコン酸ナトリウム等｝等が挙げられる。スルホネートを有するラジカル重合性モノマモノマーとしては、炭素数３〜１０のビニルスルホン酸塩｛（メタ）アリルスルホン酸ナトリウム、スチレンスルホン酸ナトリウム及びα−メチルスチレンスルホン酸ナトリウム等｝、炭素数５〜１０の（メタ）アクリロイルオキシアルキルスルホン酸塩｛（メタ）アクリロキシプロパンスルホン酸ナトリウム、２−ヒドロキシ−３−（メタ）アクリロキシプロパンスルホン酸ナトリウム及び２−（メタ）アクリロキシエタンスルホン酸ナトリウム等｝及び炭素数５〜１０の（メタ）アクリロイルアミノアルキルスルホン酸塩｛２−（メタ）アクリロイルアミノ−２，２−ジメチルエタンスルホン酸ナトリウム、２−（メタ）アクリルアミノ−２−メチルプロパンスルホン酸ナトリウム及び３−（メタ）アクリルアミノ−２−ヒドロキシプロパンスルホン酸ナトリウム等｝等が挙げられる。スホネート基を有するラジカル重合性モノマーとしては、炭素数５〜１０の（メタ）アクリル酸アルキル（アルキルの炭素数２〜６）ホスホン酸塩｛２−アクリロイルオキシエチルホスホン酸ナトリウム等｝等が挙げられる。これらのポリアニオンのうち、カルボキシレートを有するラジカル重合性モノマーのラジカル重合体及びスルホネートを有するラジカル重合性モノマーのラジカル重合体が好ましく、さらに好ましくはカルボキシレートを有するラジカル重合性モノマーのラジカル重合体であり、カルボキシレートを有するラジカル重合性モノマーのうち、（メタ）アクリル酸ナトリウムが好ましい。
【００８１】
表面改質剤（Ｎ）の２５℃における粘度（ｃＳｔ）は、架橋重合体粒子（Ｓ）との均一混合性及び（Ｓ）の内部への浸透性等の観点から、１０〜２，０００が好ましく、さらに好ましくは１５〜１，５００、特に好ましくは２０〜１０００である。すなわち、表面改質剤（Ｎ）の２５℃における粘度（ｃＳｔ）は、１０以上が好ましく、さらに好ましくは１５以上、特に好ましくは２０以上であり、また２，０００以下が好ましく、さらに好ましくは１，５００以下、特に好ましくは１０００以下である。
【００８２】
これらの表面改質剤（Ｎ）は二種以上を併用することもできる。表面改質剤（Ｎ）は、水又は揮発性溶剤に、溶解又は乳化した形態でも使用できる。
揮発性溶剤としては、表面改質剤（Ｍ）と同様のものが使用でき、好ましい範囲等も同じである。
【００８３】
表面改質剤（Ｎ）の使用量（重量％）は、架橋重合体粒子（Ｓ）の重量に基づいて、０．００１〜３が好ましく、さらに好ましくは０．００５〜２、特に好ましくは０．０７〜１．５、最も好ましくは０．１〜１．０である。すなわち、表面改質剤（Ｎ）の使用量（重量％）は、架橋重合体粒子（Ｓ）の重量に基づいて、０．００１以上が好ましく、さらに好ましくは０．００５以上、特に好ましくは０．０７以上、最も好ましくは０．１以上であり、また３以下が好ましく、さらに好ましくは２以下、特に好ましくは１．５以下、最も好ましくは１．０以下である。この範囲未満では表面改質剤（Ｎ）で処理されていない吸水性重合体粒子（Ｓ）との効果面で差が現れにくく、この範囲を越えると粉体流動性の面で好ましくない傾向にある。
【００８４】
架橋重合体粒子（Ｙ）は、架橋重合体粒子（Ｓ）と表面改質剤（Ｎ）とからなればよいが、架橋重合体粒子（Ｓ）の表面近傍に（Ｎ）が存在することが好ましく、架橋重合体粒子（Ｓ）の重合後、架橋重合体粒子（Ｓ）と（Ｎ）とを混合・処理することが望ましい。架橋重合体粒子（Ｓ）と表面改質剤（Ｎ）とを混合・処理して架橋重合体粒子（Ｙ）を得る工程及び方法は、架橋重合体粒子（Ｓ）と表面改質剤（Ｍ）と混合・処理して架橋重合体粒子（Ｘ）を得るのと同じ工程及び方法を適用でき、好ましい範囲も同じである。
【００８５】
表面改質剤（Ｎ）の粘度が１，０００〜２，０００ｃＳｔ又はこれ以上の場合、架橋重合体粒子（Ｓ）及び／又は改質剤（Ｎ）を加熱（３０〜２００℃が好ましく、さらに好ましくは４０〜１６０℃、特に好ましくは５０〜１２０℃）してから架橋重合体粒子（Ｓ）と（Ｍ）とを混合・処理することができる。すなわち、この場合、架橋重合体粒子（Ｓ）及び／又は改質剤（Ｎ）の加熱温度（℃）は、３０以上が好ましく、さらに好ましくは４０以上、特に好ましくは以上であり、また２００以下が好ましく、さらに好ましくは１６０以下、特に好ましくは１２０以下である。架橋重合体粒子（Ｓ）が表面架橋剤でその粒子の表面近傍を表面架橋処理された架橋重合体粒子（Ｓ）である場合は、表面架橋剤（またはこの溶液）の中に表面改質剤（Ｎ）を添加しておいてもよい。
表面改質剤（Ｎ）の結合基の結合様式が主に共有結合の場合、架橋重合体と（Ｎ）とを反応させる工程、加熱温度及び反応時間はは、表面改質剤（Ｍ）と同様であり、好ましい範囲も同じである。
【００８６】
架橋重合体粒子（Ｘ）及び架橋重合体粒子（Ｙ）は、架橋重合体粒子（Ｓ）を表面改質剤（Ｍ）又は表面改質剤（Ｎ）で表面処理して得られるが、架橋重合体粒子（Ｘ）に使用する架橋重合体（Ｓ）と、架橋重合体粒子（Ｙ）に使用する架橋重合体粒子（Ｓ）は同一であっても異なっていてもよい。異なる場合としては、架橋重合体粒子（Ｘ）に使用する架橋重合体粒子（Ｓ）の製造法が懸濁重合法であって、架橋重合体粒子（Ｙ）に使用する架橋重合体粒子（Ｓ）の製造法が水溶液重合である場合等が挙げられる。
【００８７】
生理食塩水（０．９重量％の塩化ナトリウム水溶液）に対する表面処理架橋重合体粒子（Ｘ）及び表面処理架橋重合体粒子（Ｙ）の吸収倍率（ｇ／ｇ）は、３２以上が好ましく、さらに好ましくは３７〜８２、特に好ましくは４２〜７２である。すなわち、生理食塩水に対する表面処理架橋重合体粒子（Ｘ）及び表面処理架橋重合体粒子（Ｙ）の吸収倍率（ｇ／ｇ）は、３２以上が好ましく、さらに好ましくは３７以上、特に好ましくは４２以上であり、またさらに好ましくは８２以下、特に好ましくは７２以下である。生理食塩水に対する加圧下（２０ｇ／ｃｍ^２）の架橋重合体粒子（Ｓ）の吸収倍率（ｇ／ｇ）は、１３以上が好ましく、さらに好ましくは１５〜７０、特に好ましくは２０〜６０である。すなわち、生理食塩水に対する加圧下（２０ｇ／ｃｍ^２）の架橋重合体粒子（Ｓ）の吸収倍率（ｇ／ｇ）は、１３以上が好ましく、さらに好ましくは１５以上、特に好ましくは２０以上であり、またさらに好ましくは７０以下、特に好ましくは６０以下である。
【００８８】
本発明の吸収剤において、架橋重合体粒子（Ｘ）の含有量（重量％）は、架橋重合体粒子（Ｘ）及び架橋重合体粒子（Ｙ）の合計重量に基づいて、２０〜８０が好ましく、さらに好ましくは３０〜７０、特に好ましくは４０〜６０、最も好ましくは４５〜５５である。すなわち、架橋重合体粒子（Ｘ）の含有量（重量％）は、架橋重合体粒子（Ｘ）及び架橋重合体粒子（Ｙ）の合計重量に基づいて、２０以上が好ましく、さらに好ましくは３０以上、特に好ましくは４０以上、最も好ましくは４５以上であり、また８０以下が好ましく、さらに好ましくは７０以下、特に好ましくは６０以下、最も好ましくは５５以下である。また、架橋重合体粒子（Ｙ）の含有量（重量％）は、架橋重合体粒子（Ｘ）及び架橋重合体粒子（Ｙ）の合計重量に基づいて、２０〜８０が好ましく、さらに好ましくは３０〜７０、特に好ましくは４０〜６０、最も好ましくは４５〜５５である
【００８９】
本発明の吸収剤は、架橋重合体粒子（Ｘ）及び架橋重合体粒子（Ｙ）を均一混合されていればよく、架橋重合粒子（Ｘ）と架橋重合粒子（Ｙ）とを配合し均一混合させるための混合装置としては、従来からの公知の装置を使用することができる。このような公知の装置としては、双腕型ニーダー、インターナルミキサー（バンバリーミキサー）、セルフクリーニング型ミキサー、ギアコンパウンダー、スクリュー型押し出し機、スクリュー型ニーダー及びミンチ機等が挙げられ、これらの複数種類を組み合わせて使用することもできる。
【００９０】
本発明の吸収剤には、必要により添加剤（Ｃ）を添加することができる。添加剤（Ｃ）としては、例えば、防腐剤、防かび剤、抗菌剤、酸化防止剤、紫外線吸収剤、着色剤、芳香剤、消臭剤、無機質粉末及び有機質繊維状物等が使用できる。防腐剤としては、サリチル酸、ソルビン酸、デヒドロ酢酸及びメチルナフトキノン等の保存料、並びにクロラミンＢ及びニトロフラゾン等の殺菌料等が挙げられる。防かび剤としては、ｐ−オキシ安息香酸ブチル等が挙げられ、抗菌剤としては、塩化ベンザルコニウム塩及びグルコン酸クロルヘキシジン等が挙げられる。酸化防止剤としては、トリエチレングリコール−ビス−［３−（３−ｔ−ブチル−５−メチル−４−ヒドロキシフェニル）プロピオネート］、１，６−ヘキサンジオール−ビス［３−（３，５−ジ−ｔ−ブチル−４−ヒドロキシフェニル）プロピオネート］、オクタデシル−３−（３，５−ジ−ｔ−ブチル−４−ヒドトキシフェニルプロピオネート及び３，５−ジ−ｔ−ブチル−４−ヒドロキシベンジルフォスフォネート−ジエチルエステル等のヒンダードフェノール系酸化防止剤、ｎ−ブチルアミン、トリエチルアミン及びジエチルアミノメチルメタクリレート等のアミン系酸化防止剤、並びにこれらの２種以上の混合物等が挙げられる。紫外線吸収剤としては、２−（５−メチル−２−ヒドロキシフェニル）ベンゾトリアゾール、２−（３，５−ジ−ｔ−ブチル−２−ヒドロキシフェニル）ベンゾトリアゾール、２−（３，５−ジ−ｔ−ブチル−２−ヒドロキシフェニル）−５−クロロベンゾトリアゾール及び２−（３，５−ジ−ｔ−アミル−２−ヒドロキシフェニル）ベンゾトリアゾール等のベンゾトリアゾール系紫外線吸収剤、２−（４，６−ジフェニル−１，３，５−トリアジン−２−イル）−５−［（ヘキシル）オキシ］−フェノール等のトリアジン系紫外線吸収剤、２−ヒドロキシ−４−ｎ−オクチルオキシベンゾフェノン等のベンゾフェノン系紫外線吸収剤、２−エトキシ−２’−エチルオキサリック酸ビスアニリド等の蓚酸アニリド系紫外線吸収剤等、並びにこれらの２種以上の混合物等が挙げられる。着色剤としては、例えば、カーボンブラック、酸化チタン及びフェライト等の無機顔料、アゾレーキ系、ベンジイミダゾロン系及びフタロシアニン系等の有機顔料、並びにニグロシン系及びアニリン系等の染料等が挙げられる。芳香剤としては、例えば、じゃ香、アビエス油及びテレピン油等の天然香料、並びにメントール、シトラール、ｐ−メチルアセトフェノン及びフローラル等の合成香料等が挙げられる。消臭剤としては、例えば、ゼオライト、シリカ、フラボノイド及びシクロデキストリン等が挙げられる。無機質粉末としては、炭酸カルシウム、カオリン、タルク、マイカ、ベントナイト、クレー、セリサイト、アスベスト、ガラス繊維、炭素繊維、ガラス粉、ガラスバルーン、シラスバルーン、石炭粉、金属粉末、セラミック粉末、シリカ、ゼオライト及びスレート粉等が挙げられる。形態は任意でよく、光散乱法で求めた個数平均粒径は０．１μｍ〜１ｍｍが好ましい。有機質繊維状物としては、天然繊維〔セルロース（木綿、オガクズ、ワラ等）、並びにその他の草炭、羊毛、ミクロフィブリル及びバクテリアセルロース等〕、人造繊維（レーヨン及びアセテート等のセルロース系等）、合成繊維（ポリアミド、ポリエステル及びアクリル等）、パルプ〔メカニカルパルプ（丸太からの砕木パルプ及びアスプルンド法砕木パルプ等）、ケミカルパルプ（亜硫酸パルプ、ソーダパルプ、硫酸塩パルプ、硝酸パルプ及び塩素パルプ等）、セミケミカルパルプ、再生パルプ（例えば、パルプを一旦製紙して作った紙の機械的破砕又は粉砕物、又は故紙の機械的破砕若しくは粉砕物である再生故紙パルプ等）等が挙げられる。
【００９１】
添加剤（Ｃ）を使用する場合、これらの添加量（重量％）は用途によって異なるが、架橋重合体粒子（Ｘ）及び架橋重合体粒子（Ｙ）の合計重量に基づいて、０．０１〜２０が好ましく、さらに好ましくは０．０２〜１０、特に好ましくは０．０３〜８である。すなわち、この場合、これらの添加量（重量％）は、架橋重合体粒子（Ｘ）及び架橋重合体粒子（Ｙ）の合計重量に基づいて、０．０１以上が好ましく、さらに好ましくは０．０２以上、特に好ましくは０．０３以上であり、また２０以下が好ましく、さらに好ましくは１０以下、特に好ましくは８以下である。
【００９２】
添加剤（Ｃ）を使用する場合、任意の段階で添加することができ、以下の▲１▼〜▲４▼等が挙げられる。
▲１▼あらかじめ架橋重合体粒子（Ｓ）、架橋重合体粒子（Ｘ）及び／又は架橋重合体粒子（Ｙ）に添加剤（Ｃ）を混合しておく方法。
▲２▼表面改質剤（Ｍ）又は表面改質剤（Ｎ）に添加剤（Ｃ）を混合してから、架橋重合体粒子（Ｓ）と混合・処理する方法。
▲３▼架橋重合体粒子（Ｓ）と表面改質剤（Ｍ）又は表面改質剤（Ｎ）とを混合しながら添加剤（Ｃ）を添加する方法。
▲４▼架橋重合体粒子（Ｓ）を表面改質剤（Ｍ）又は表面改質剤（Ｎ）で処理した後に添加剤（Ｃ）を添加・混合する方法。
これらの方法の中で、▲２▼、▲３▼及び▲４▼の方法が好ましく、さらに好ましくは▲３▼及び▲４▼の方法である。
【００９３】
本発明の吸収剤は、吸水及び／又は保水が要望される吸収性物品等（特に血液の吸収及び／又は保血が要望されている吸収性物品）に好適であり、紙おむつ（子供用紙おむつ及び大人用紙おむつ）、生理用ナプキン、失禁用パッド、母乳パッド、手術用アンダーパッド及びペットシート等の衛生用品（特に生理用ナプキン）に最適である。さらに鮮度保持材、保冷材、乾燥剤、ドリップ吸収材、結露防止剤、植物や土壌等の保水剤、ヘドロ等の凝固剤、土木建築用の止水材やパッキング材、電線ケーブルや光ファイバーケーブルの止水材及び人工雪等の各種用途にも有用である。すなわち、本発明の吸収剤により吸収できる被吸収液体としては特に限定はないが、尿、血液及びその他の体液、並びにドリップ、海水、工業廃水及び泥水等が挙げられる。これらのうち、尿、血液及びその他の体液が好ましく、さらに好ましくは血液及びその他の体液である。
【００９４】
【実施例】
以下、実施例及び比較例により本発明をさらに説明するが、本発明はこれらに限定されるものではない。なお、特に定めない限り、部は重量部、％は重量％を示す。また、血液の吸収倍率、血液の吸収速度は下記の方法により測定した。なお、生理食塩水に対する吸収倍率、生理食塩水に対する加圧下（２０ｇ／ｃｍ^２）の吸収倍率の測定方法は、上記と同様である。
【００９５】
＜血液吸収量＞
２５０メッシュのナイロン網で作成したティーバッグ（縦２０ｃｍ、横１０ｃｍ）に、サンプル１．００ｇを入れ、馬血（３．８％クエン酸含有；ジャパン・ラム社製）３００ｍｌ中に６０分間浸漬して吸収させた後、１５分間吊して液切りしてから増加重量を測定して血液吸収量（ｇ／ｇ）とする。
【００９６】
＜血液吸収速度＞
直径６０ｍｍのシャーレにサンプル０．５ｇをシャーレ底面全体に均一に撒布し、馬血２．５ｇを中央に２秒間で滴下し、馬血がサンプルに吸収されサンプルの表面から馬血の液滴が無くなるまでの時間を肉眼で測定して１回目の血液吸収速度（秒）とする。１回目の吸収速度測定終了時から１０分後に、再度馬血２．５ｇを滴下し、吸収が完了するまでの時間を測定して２回目の血液吸収速度（秒）とする。
【００９７】
合成例Ｘ１
ガラス製反応容器にアクリル酸ナトリウム９５部、アクリル酸２７部、Ｎ，Ｎ’−メチレンビスアクリルアミド０．３部及び脱イオン水４３０部を仕込み、撹拌・混合しながら内容物の温度を５℃に保った。内容物に窒素を流入した後、過酸化水素の１％水溶液１部及びアスコルビン酸の０．３％水溶液１部を添加して重合を開始させた。過酸化水素及びアスコルビン酸を添加した１０分後に重合による温度の上昇が始まり、温度が上昇し始めてから４０分後に６０℃に到達した。さらに、６０℃で１２時間重合させ含水樹脂を得た。この含水樹脂を１３０〜１５０℃で２０分間熱風乾燥し、ジューサーミキサーを用いて粉砕して６０メッシュ（２５０μｍ）のＪＩＳ標準篩をパスせず３０メッシュ（５９０μｍ）のＪＩＳ標準篩をパスする粒子を収集することにより粒度調整して、２５０〜５９０μｍの架橋重合体粒子（Ｓ１）を得た。
【００９８】
架橋重合体粒子（Ｓ１）の赤外水分計（ＦＤ−１００型、Ｋｅｔｔ製）で測定した水分は１５％であった。架橋重合体粒子（Ｓ１）１００部を卓上型ニーダー（ＰＮ−１型、入江商会製）に入れ、これにパーフルオロアルキルエチレンオキサイド付加物［大日本インキ化学、メガファックＦ−１４２Ｄ、表面張力１９．０ダイン／ｃｍ］０．０２部を添加し、２５℃にて３０分間、５０ｒｐｍで撹拌し、架橋重合体粒子を得た。この架橋重合体粒子１００ｇを卓上型ニーダーにて５０ｒｐｍで撹拌しながら、エチレングリコールジグリシジルエーテルの１０％水溶液１部を噴霧し、約１４０℃で３０分間加熱処理することにより表面近傍を架橋処理し、さらに約１４０℃で加熱処理し水分を５％に調整することにより、架橋重合体粒子（Ｘ１）を得た。
【００９９】
合成例Ｘ２
合成例Ｘ１において、パーフルオロアルキルエチレンオキサイド付加物を添加せず、アミノ変成シリコーン［信越化学社、商品名：ＫＦ８８０（表面張力２４ダイン／ｃｍ）］を用いる他は合成例Ｘ１と同様にして架橋重合体粒子（Ｘ２）を得た。
【０１００】
合成例Ｘ３
合成例Ｘ１において、パーフルオロアルキルエチレンオキサイド付加物を添加せず、ポリプロピレン無水マレイン酸変性物［三洋化成工業社、商品名：ユーメックス１００ＴＳ、表面張力２６ダイン／ｃｍ］を用いる他は合成例Ｘ１と同様にして架橋重合体粒子（Ｘ３）を得た。
【０１０１】
合成例Ｘ４
アクリル酸１４５．４部を９．４部の水で希釈し、３０〜２０℃に冷却しつつ２５％の水酸化ナトリウム水溶液２４２．３部を加えて中和した。この溶液にエチレングリコールジグリシジルエーテル（ナガセ化成工業社製、デナコールＥＸ−８１０）を０．０７２７部、次亜リン酸ソーダ１水和物を０．０１４６部及び過硫酸カリウムを０．０７２７部添加して溶解させ、モノマー水溶液とした。次いで、撹拌機、還流冷却器、温度計及び窒素ガス導入管を備えた４つ口フラスコに、シクロヘキサン６２４部を入れ、これにポリオキシエチレンノクチルフェニルエーテルリン酸エステル（第一工業製薬社、商品名：ブライサーフＡ２１０Ｇ）１．５６部を添加して溶解させた後、４００ｒｐｍで撹拌しつつ窒素ガスを導入した後、７０℃まで昇温した。そして、７０℃に温度を保ったまま、調整したモノマー水溶液を６．６部／分で６分間滴下した。６分後７５℃で１５分間保持した後、残りのモノマー水溶液を６．６部／分で５４分間に亘って滴下した。その後、７５℃で３０分熟成した。この後、水をシクロヘキサンとの共沸によって樹脂の含水率が約２０％（赤外水分計（ＦＤ−１００型、Ｋｅｔｔ製）で測定）となるまで除去した。３０℃に冷却し撹拌を停止すると、樹脂粒子が沈降したので、デカンテーションにより、樹脂粒子とシクロヘキサンとを分離した。この樹脂粒子８０部とシクロヘキサン１４０部とをナスフラスコに入れ、これにグリセリンポリグリシジルエーテル（ナガセ化成工業社、商品名：デナコールＥＸ−３１４）０．３５重量％とパーフルオロアルキルエチレンオキサイド付加物（大日本インキ化学社、商品名：メガファックＦ−１４２Ｄ、表面張力：１９．０）０．０２５重量％を含むシクロヘキサン溶液３．４部を添加した後、６０℃で加熱して３０分間保持した後、さらに加熱してシクロヘキサンの還流下に３０分間保持した。次いで濾過して樹脂粒子を取得し８０℃で減圧乾燥することにより、架橋重合体粒子（Ｘ４）を得た。
【０１０２】
合成例Ｘ５
合成例Ｘ４において、パーフルオロアルキルエチレンオキサイド付加物を添加せず、アミノ変成シリコーン［信越化学社、商品名：ＫＦ８８０（表面張力２４ダイン／ｃｍ）］を用いる他は合成例Ｘ４と同様にして架橋重合体粒子（Ｘ５）を得た。
【０１０３】
合成例Ｘ６
合成例Ｘ４において、パーフルオロアルキルエチレンオキサイド付加物を添加せず、ポリプロピレン無水マレイン酸変性物［三洋化成工業社、商品名：ユーメックス１００ＴＳ、表面張力２６．０］を用いる他は合成例Ｘ４と同様にして架橋重合体粒子（Ｘ６）を得た。
【０１０４】
合成例Ｙ１
合成例Ｘ１において、パーフルオロアルキルエチレンオキサイド付加物を添加せず、ポリエチレングリコール［三洋化成社、商品名：ＰＥＧ２００（表面張力５５ダイン／ｃｍ）］を用いる他は合成例Ｘ１と同様にして架橋重合体粒子（Ｙ１）を得た。
【０１０５】
合成例Ｙ２
合成例Ｘ１において、パーフルオロアルキルエチレンオキサイド付加物を添加せず、ポリカチオン［三洋化成工業社、商品名：サンフロックＣＤ−２６９Ｐ（表面張力７２ダイン／ｃｍ）］を用いる他は合成例Ｘ１と同様にして架橋重合体粒子（Ｙ２）を得た。
【０１０６】
合成例Ｙ３
合成例Ｘ４において、パーフルオロアルキルエチレンオキサイド付加物を添加せず、ポリエチレングリコール［三洋化成社、商品名：ＰＥＧ２００（表面張力５５ダイン／ｃｍ）］を用いる他は合成例Ｘ４と同様にして架橋重合体粒子（Ｙ３）を得た。
【０１０７】
合成例Ｙ４
合成例Ｘ４において、パーフルオロアルキルエチレンオキサイド付加物を添加せず、ポリカチオン［三洋化成工業社、商品名：サンフロックＣＤ−２６９Ｐ（表面張力７２ダイン／ｃｍ）］を用いる他は合成例Ｘ４と同様にして架橋重合体粒子（Ｙ４）を得た。
【０１０８】
＜実施例１＞
架橋重合体粒子（Ｘ１）１００部及び架橋重合体粒子（Ｙ１）１００部を混合攪拌（細川ミクロン製高速攪拌タービュライザー：回転数２０００ｒｐｍ）し、本発明の吸収剤１を得た。
【０１０９】
＜実施例２＞
架橋重合体粒子（Ｘ１）１００部及び架橋重合体粒子（Ｙ２）１００部を混合攪拌（細川ミクロン製高速攪拌タービュライザー：回転数２０００ｒｐｍ）し、本発明の吸収剤２を得た。
【０１１０】
＜実施例３＞
架橋重合体粒子（Ｘ２）１００部及び架橋重合体粒子（Ｙ１）１００部を混合攪拌（細川ミクロン製高速攪拌タービュライザー：回転数２０００ｒｐｍ）し、本発明の吸収剤３を得た。
【０１１１】
＜実施例４＞
架橋重合体粒子（Ｘ２）１００部及び架橋重合体粒子（Ｙ２）１００部を混合攪拌（細川ミクロン製高速攪拌タービュライザー：回転数２０００ｒｐｍ）し、本発明の吸収剤４を得た。
【０１１２】
＜実施例５＞
架橋重合体粒子（Ｘ３）１００部及び架橋重合体粒子（Ｙ１）１００部を混合攪拌（細川ミクロン製高速攪拌タービュライザー：回転数２０００ｒｐｍ）し、本発明の吸収剤５を得た。
【０１１３】
＜実施例６＞
架橋重合体粒子（Ｘ３）１００部及び架橋重合体粒子（Ｙ２）１００部を混合攪拌（細川ミクロン製高速攪拌タービュライザー：回転数２０００ｒｐｍ）し、本発明の吸収剤６を得た。
【０１１４】
＜実施例７＞
架橋重合体粒子（Ｘ４）１００部及び架橋重合体粒子（Ｙ３）１００部を混合攪拌（細川ミクロン製高速攪拌タービュライザー：回転数２０００ｒｐｍ）し、本発明の吸収剤７を得た。
【０１１５】
＜実施例８＞
架橋重合体粒子（Ｘ４）１００部及び架橋重合体粒子（Ｙ４）１００部を混合攪拌（細川ミクロン製高速攪拌タービュライザー：回転数２０００ｒｐｍ）し、本発明の吸収剤８を得た。
【０１１６】
＜実施例９＞
架橋重合体粒子（Ｘ５）１００部及び架橋重合体粒子（Ｙ３）１００部を混合攪拌（細川ミクロン製高速攪拌タービュライザー：回転数２０００ｒｐｍ）し、本発明の吸収剤９を得た。
【０１１７】
＜実施例１０＞
架橋重合体粒子（Ｘ５）１００部及び架橋重合体粒子（Ｙ４）１００部を混合攪拌（細川ミクロン製高速攪拌タービュライザー：回転数２０００ｒｐｍ）し、本発明の吸収剤１０を得た。
【０１１８】
＜実施例１１＞
架橋重合体粒子（Ｘ６）１００部及び架橋重合体粒子（Ｙ３）１００部を混合攪拌（細川ミクロン製高速攪拌タービュライザー：回転数２０００ｒｐｍ）し、本発明の吸収剤１１を得た。
【０１１９】
＜実施例１２＞
架橋重合体粒子（Ｘ６）１００部及び架橋重合体粒子（Ｙ４）１００部を混合攪拌（細川ミクロン製高速攪拌タービュライザー：回転数２０００ｒｐｍ）し、本発明の吸収剤１２を得た。
【０１２０】
＜比較例１〜１０＞
合成例で得た架橋重合体粒子（Ｘ１）〜（Ｘ６）及び（Ｙ１）〜（Ｙ４）をそのまま比較例の吸収剤とした。これらの関係を表１に示す。
【表１】

【０１２１】
実施例１〜１２及び比較例１〜１０の吸収剤について、生理食塩水に対する吸収倍率、生理食塩水に対する加圧下の吸収倍率、血液吸収量及び血液吸収速度の評価を行い、その結果を表２に示す。
【表２】

【０１２２】
表２から判るように、本発明の吸収剤（実施例１〜１２）と比較例１〜１０の吸収剤とを比較すると、本発明の食塩水に対する吸収倍率、食塩水に対する加圧下での吸収倍率及び血液吸収量は、比較例のそれらと同等以上であり、本発明の血液吸水速度は格段に優れる。
【０１２３】
【発明の効果】
本発明の吸収剤は、吸水性樹脂にとって課題であった吸収速度及び吸収量のバランスに優れ、共に優れた性能を発揮する。特に血液の吸水速度については、格段に優れるため、血液の吸収剤として最適である。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an absorbent and an absorbent article using the same.
[0002]
[Prior art]
The higher the water-absorbing capacity of the water-absorbing resin, the stronger the affinity with water, so that a gel is formed at the contact portion with water, preventing uniform penetration of water into the inside of the particles (a phenomenon called gel blocking). ). In addition, since blood and the like adhere to the surface of the resin particles, uniform penetration of water into the inside of the particles is hindered, and liquid permeability is reduced. There is a problem that the absorption speed and the amount of absorption into water decrease. In order to improve these problems, for example, resin particles (1) to (4) are known.
{Circle around (1)} The average particle diameter is 0.05 μm or less, and the specific surface area is 50 m. ² / G or more of water-absorbent resin particles obtained by mixing fine powdered hydrophobic silica (Patent Document 1).
{Circle around (2)} Water-absorbing resin particles obtained by adding inorganic powders such as hydrous silicon dioxide (white carbon, kaolin, clay, etc.), hydrous aluminum hydroxide and hydrous titanium oxide (Patent Document 2).
{Circle around (3)} Water-absorbent resin particles obtained by mixing stearic acid and inorganic powder and coating the surface with stearic acid (Patent Document 3).
{Circle around (4)} Water-absorbing resin particles whose surfaces are treated with an organic polysiloxane to make them hydrophobic (Patent Document 4).
[0003]
[Patent Document 1]
JP-A-56-133028
[Patent Document 2]
JP-A-59-80459
[Patent Document 3]
JP-A-63-105064
[Patent Document 4]
Japanese Patent No. 3169133
[0004]
[Problems to be solved by the invention]
However, in the water-absorbent resin particles (1) to (4), although the gel blocking between the particles is suppressed and the absorption amount is improved, the absorption rate tends to decrease because the surface of the resin particles becomes hydrophobic. . In particular, blood has a high viscosity and contains ions and the like in a high concentration, so that the wettability between the hydrophobic surface of the water-absorbent resin particles and the blood is deteriorated, and the absorption rate to the blood is easily reduced. As described above, in any case, it was difficult to balance the absorption speed and the absorption amount. That is, an object of the present invention is to provide an absorbent having an excellent absorption amount and an extremely excellent absorption rate.
[0005]
[Means for Solving the Problems]
The present inventors have conducted intensive studies to achieve the above object, and as a result, have found that the use of specific crosslinked polymer particles is excellent in absorption rate and absorption amount, and reached the present invention. That is, the characteristics of the absorbent of the present invention include a crosslinked polymer particle (S) having (meth) acrylic acid (salt) as a main structural unit and a surface modifier (M) having a surface tension of 10 to 30 dynes / cm. ), A surface-treated crosslinked polymer particle (X) comprising a crosslinked polymer particle (S) and a surface modifier (N) having a surface tension of 40 to 80 dynes / cm. )).
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
(Meth) acrylic acid (salt) means acrylic acid, methacrylic acid, acrylate and methacrylate. Examples of the acrylate and methacrylate include alkali metal (eg, lithium, potassium, and sodium) salts, alkaline earth metal (eg, magnesium and calcium) salts, and ammonium salts of acrylic acid or methacrylic acid. . Of these, alkali metal salts are preferred, sodium salts, lithium salts and potassium salts are more preferred, sodium salts and lithium salts are particularly preferred, and sodium salts are most preferred.
[0007]
If the crosslinkable polymer particles (S) have (meth) acrylic acid (salt) as the main structural unit, the (meth) acrylic acid (salt) and another copolymerizable vinyl monomer copolymerizable with (meth) acrylic acid (salt) are used. It can be copolymerized. Other copolymerized vinyl monomers include a nonionic copolymerized vinyl monomer (i) and a crosslinkable vinyl monomer (ii).
[0008]
Examples of the nonionic copolymerized vinyl monomer (i) include (i-1) a hydroxyl group (-OH) -containing vinyl monomer, (i-2) a vinyl monomer having a carbamoyl group or a mono- or di-alkylcarbamoyl group, and ( i-3) Vinyl monomers having an epoxy group or an isocyanato group are included.
[0009]
(I-1) Examples of the hydroxyl group (-OH) -containing vinyl monomer include monoethylenically unsaturated alcohols (such as (meth) allyl alcohol and (meth) propenyl alcohol), dihydric to hexavalent or higher polyols (carbon number Monoethylenically unsaturated carboxylic acid ester or monoethylenically unsaturated ether @ hydroxyethyl (meth) acrylate of 2 to 20 alkylene glycols, glycerin, polyalkylene (2 to 4 carbon atoms) glycol (molecular weight: 106 to 2,000), etc. , Hydroxypropyl (meth) acrylate, triethylene glycol (meth) acrylate, glycerin mono (meth) acrylate, poly (oxyethylene / oxypropylene) (random and / or block) glycol mono (meth) allyl ether (terminal hydroxyl group is ether Or esterification may be) and the like}, and N- alkylol (meth) acrylate {N- methylol (meth) acrylate and the like}.
[0010]
(I-2) Examples of vinyl monomers having a carbamoyl group or a mono- or di-alkylcarbamoyl group include (meth) acrylamide, N-alkyl (C1-8) (meth) acrylamide (N-methylacrylamide, etc.) And N, N-dialkyl (C1-8) acrylamide (N, N-dimethylacrylamide and N, N-di-n- or i-propylacrylamide, etc.) and the like, and N-hydroxyalkyl (carbon (1-8) (meth) acrylamide {N-methylol (meth) acrylamide, N-hydroxyethyl (meth) acrylamide, etc.}; N, N-dihydroxyalkyl (C1-8) (meth) acrylamide {N, N -Dihydroxyethyl (meth) acrylamide, etc. and vinyl lactam {N-vinylpyrroli Emissions, etc.} and the like can also be used.
[0011]
(I-3) Examples of the vinyl monomer having an epoxy group or an isocyanato group include glycidyl (meth) acrylate, (meth) acryloyl isocyanate, and (meth) acryloylethyl isocyanate.
[0012]
One or more of these nonionic copolymerized vinyl monomers may be used. Among these nonionic copolymerized vinyl monomers (i), hydroxyl group (-OH) -containing vinyl monomers are preferable, more preferably monoethylenically unsaturated carboxylic acid esters, and particularly preferably hydroxyethyl (meth) acrylate.
[0013]
When the nonionic copolymerized vinyl monomer (i) is used, the content (% by weight) of the nonionic copolymerized vinyl monomer unit is preferably 20 or less based on the weight of the (meth) acrylic acid (salt) unit. It is preferably at most 2, more preferably at most 1, most preferably at most 0.1.
[0014]
Examples of the crosslinkable vinyl monomer (ii) include a crosslinkable vinyl monomer having two or more radical polymerizable groups selected from the group consisting of a (meth) acryloyl group, a vinyloxy group, an allyloxy group, and an allyl group. N'-methylenebis (meth) acrylamide, ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, glycerin di- or tri- (meth) acrylate, trimethylolpropane di- or Tri- (meth) acrylate, di- or tri-allylamine, triallyl cyanurate, triallyl isocyanurate, tetraallyloxyethane, pentaerythritol allyl ether and the like.
[0015]
These crosslinkable vinyl monomers may be used alone or in combination of two or more. Among these crosslinkable vinyl monomers (ii), N, N'-methylenebis (meth) acrylamide, ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, glycerin di- Or tri- (meth) acrylate, trimethylolpropane di- or tri (meth) acrylate, di- or tri-allylamine, triallyl cyanurello, triallyl isocyanurate, tetraallyloxyethane and pentaerythritol allyl ether are preferred. And more preferably N, N'-methylenebis (meth) acrylamide, ethylene glycol di- or tri- (meth) acrylate, trimethylolpropane di- or tri- (meth) acrylate, tetraallyloxy Tan, pentaerythritol allyl ether and triallyl amine.
[0016]
When the crosslinkable vinyl monomer (ii) is used, the content (% by weight) of the crosslinkable vinyl monomer unit is based on the weight of the (meth) acrylic acid (salt) unit and the nonionic copolymerized vinyl monomer (i) unit. On the basis thereof, 0.001 to 10, more preferably 0.005 to 5, particularly preferably 0.007 to 2, and most preferably 0.01 to 1. That is, in this case, the content (% by weight) of the crosslinkable vinyl monomer unit is preferably 0.001 or more, more preferably 0.005 or more, and particularly preferably 0.007 or more, based on the weight of the vinyl monomer unit. , Most preferably 0.01 or more, and 10 or less, more preferably 5 or less, particularly preferably 2 or less, and most preferably 1 or less.
[0017]
The crosslinked polymer particles (S) can be prepared by the following methods: (1) radical polymerization of an aqueous solution (adiabatic polymerization, thin-film polymerization and spray polymerization, etc.) described in JP-A-55-133413 and (2) JP-B-54-30710. And a known method such as reversed-phase suspension radical polymerization described in JP-A-56-26909 or JP-A-1-5808.
[0018]
In the case of aqueous polymerization, the polymerization concentration, that is, the concentration (% by weight) of (meth) acrylic acid (salt) and other copolymerized vinyl monomers in the aqueous polymerization solution depends on the industrial productivity and the absorption capacity of the crosslinked polymer particles. From the viewpoint, it is preferably from 20 to 45, more preferably from 23 to 40, and particularly preferably from 25 to 35, based on the total weight of the aqueous polymerization solution. That is, in this case, the polymerization concentration, that is, the concentration (% by weight) of (meth) acrylic acid (salt) and other copolymerized vinyl monomers in the aqueous polymerization solution is preferably 20 or more based on the total weight of the aqueous polymerization solution, It is more preferably 23 or more, particularly preferably 25 or more, and preferably 45 or less, more preferably 40 or less, particularly preferably 35 or less. Further, the amount of water is preferably 80 to 30% by weight based on the weight of the aqueous polymerization solution from the viewpoints of industrial productivity and absorption capacity of the crosslinked polymer particles.
[0019]
In the aqueous solution polymerization, a water-soluble organic solvent may coexist if necessary. Examples of the water-soluble organic solvent include methanol, ethanol, and isopropyl alcohol. When a water-soluble organic solvent is used, the amount (% by weight) is preferably 40 or less, more preferably 30 or less, based on the weight of water.
[0020]
A polymerization initiator can be used for the aqueous solution polymerization.As the polymerization initiator, a conventionally known polymerization initiator and the like can be used, and an azo initiator, a peroxide initiator, a redox initiator, an organic halogen initiator, and the like can be used. included. Examples of the azo initiator include azobisisobutyronitrile, azobiscyanovaleric acid and salts thereof, 2,2'-azobis (2-amidinopropane) hydrochloride, and 2,2'-azobis (2-methyl-N- (2 -Hydroxyethyl) propionamide and the like.
[0021]
Examples of the peroxide initiator include inorganic peroxides such as hydrogen peroxide, ammonium persulfate, potassium persulfate and sodium persulfate, and organic peroxides such as benzoyl peroxide, di-t-butyl peroxide and cumene hydroperoxide. Oxide, succinic peroxide, di (2-ethoxyethyl) peroxydicarbonate, and the like. Redox initiators include alkali metal sulfites or bisulfites, reducing agents such as ammonium sulfite, ammonium bisulfite, ferric chloride, ferric sulfate or ascorbic acid and alkali metal persulfates, ammonium persulfate, Examples include those composed of a combination with an oxidizing agent such as hydrogen peroxide or an organic peroxide.
[0022]
As the organic halide, an organic halide having 1 to 15 or more carbon atoms and having 1 to 10 or more halogen atoms can be used, and alkyl halides (dichloromethane, trichloromethane, tetrachloromethane, trichlorobromomethane and Trichloroiodomethane, etc.), halogenated alkyl phenyl ketone (monochloromethyl phenyl ketone, dichloromethyl phenyl ketone, trichlorophenyl ketone, etc.), halogenated alkyl carboxylic acid (1-chloro-1-methylethyl carboxylic acid, 1-bromo-1) -Methylethyl carboxylic acid, 1-bromo-1-methylethyl carboxylic acid, 2-bromo-1-methylethyl carboxylic acid, 2-chloro-1-methylethyl carboxylic acid, and the like, and halogenated alkyl carboxylic acid alkyl esters ( 1- Methyl lomo-1-methylethylcarboxylate, ethyl 1-bromo-1-methylethylcarboxylate, octyl 1-bromo-1-methylethylcarboxylate, lauryl 1-bromo-1-methylethylcarboxylate, 1-chloro- Methyl 1-methylethylcarboxylate, ethyl 1-chloro-1-methylethylcarboxylate, octyl 1-chloro-1-methylethylcarboxylate, lauryl 1-chloro-1-methylethylcarboxylate, and the like.
[0023]
These polymerization initiators may be used alone or in combination of two or more. When an azo initiator, a peroxide initiator, or a redox initiator is used, the amount (% by weight) of these used is 0% based on the weight of (meth) acrylic acid (salt) and other copolymerized vinyl monomers. 0.0005 to 1, more preferably 0.01 to 0.5. That is, in this case, the amount (% by weight) of the polymerization initiator is preferably 0.0005 or more, more preferably 0.1%, based on the weight of (meth) acrylic acid (salt) and other copolymerized vinyl monomers. 01 or more, preferably 1 or less, and more preferably 0.5 or less.
[0024]
When an organic halogen initiator is used, the amount (% by weight) of these used is preferably 0.0005 to 10, and more preferably, based on the weight of (meth) acrylic acid (salt) and other copolymerized vinyl monomers. Is 0.001 to 5, particularly preferably 0.005 to 3. That is, in this case, the amount (% by weight) of the polymerization initiator is preferably 0.0005 or more, more preferably 0.1%, based on the weight of (meth) acrylic acid (salt) and other copolymerized vinyl monomers. 001 or more, particularly preferably 0.005 or more, and preferably 10 or less, more preferably 5 or less, particularly preferably 3 or less.
[0025]
In the aqueous solution polymerization, a conventionally known chain transfer agent may be used in combination. Examples of such a thiol (n-lauryl mercaptan, mercaptoethanol, mercaptopropanol, triethylene glycol dimercaptan, etc.), thiocarboxylic acid (thiol) Glycolic acid, thiomalic acid, etc.), secondary alcohols (isopropanol, etc.), amines (dibutylamine, etc.), hypophosphites (sodium hypophosphite, etc.). When a chain transfer agent is used, the amount (% by weight) is preferably 0.001 to 1 based on the weight of (meth) acrylic acid (salt) and other copolymerized vinyl monomers.
[0026]
The polymerization temperature (° C.) of the aqueous solution polymerization is not particularly limited and can be variously changed depending on the type of the catalyst used, but is preferably 0 to 100, more preferably 5 to 80. That is, the polymerization temperature (° C.) is preferably 0 or more, more preferably 5 or more, and is preferably 100 or less, more preferably 80 or less. In the case of a reversed-phase suspension radical polymerization method as a polymerization method, if necessary, a conventionally known dispersant or surfactant, and a conventionally known xylene, normal hexane, or a hydrocarbon solvent such as normal heptane may be used. it can.
[0027]
The crosslinked polymer particles (S) can be subjected to a surface crosslinking treatment with a surface crosslinking agent, if necessary. In the case where the surface cross-linking treatment is performed, the polymer before the surface cross-linking treatment is referred to as a polymer particle before the surface cross-linking (S ′) in order to distinguish from the cross-linked polymer particles (S) after the surface cross-linking treatment.
[0028]
Examples of the surface crosslinking agent include polyhydric glycidyl described in JP-A-59-189103, polyhydric alcohols described in JP-A-58-180233 and JP-A-61-16903, and polyamines. , Polyvalent aziridine and polyvalent isocyanate, silane coupling agents described in JP-A-61-211305 or JP-A-61-252212, and JP-A-51-136588 or JP-A-61-158588. And polyvalent metals described in JP-A-257235 and the like. Among these surface cross-linking agents, polyvalent glycidyl, polyamine, and silane coupling are preferred from the viewpoints of the absorption capacity of the absorbent of the present invention, the absorption capacity under pressure, and the surface crosslinking reaction temperature of the crosslinked polymer particles (S). Agents are preferable, and polyhydric glycidyl and silane coupling agents are more preferable, and polyhydric glycidyl is particularly preferable.
[0029]
When the surface cross-linking treatment is performed, the amount (% by weight) of the surface cross-linking agent can be variously changed depending on the type of the surface cross-linking agent, cross-linking conditions, target performance, and the like. In light of the absorption capacity of the absorbent, the weight is preferably 0.001 to 3, more preferably 0.005 to 2, and particularly preferably 0.01 to 1, based on the weight of the polymer particles (S ') before surface crosslinking. It is one. That is, in this case, the amount (% by weight) of the surface cross-linking agent used is preferably 0.001 or more, more preferably 0.005 or more, and particularly preferably, based on the weight of the polymer (S ′) before surface cross-linking. It is 0.01 or more, preferably 3 or less, more preferably 2 or less, particularly preferably 1 or less.
[0030]
The surface cross-linking treatment is performed at any stage before, during, or after the drying of the water-containing resin (WA) containing the polymer particles (S ′) before the surface cross-linking and water. From the viewpoint that the crosslinking conditions can be easily adjusted with respect to the target performance, a stage during (WA) drying or after (WA) drying is preferable. As a method for performing the surface cross-linking treatment, a conventionally known method can be applied. For example, a mixed solution containing a surface cross-linking agent, water and an organic solvent is mixed with polymer particles (S ′) before surface cross-linking or a water-containing resin (WA). A method of mixing and heat-reacting, or the like can be given. The amount of water (% by weight) used in the surface cross-linking treatment is determined from the viewpoint of appropriately permeating the surface cross-linking agent into the inside of the pre-cross-linked polymer particles (S ′). Based on the weight of S ′), it is preferably 1 to 10, more preferably 1.5 to 8, and particularly preferably 2 to 7. That is, the amount of water used (% by weight) is preferably 1 or more, more preferably 1.5 or more, particularly preferably 2 or more, based on the weight of the polymer particles (S ′) before surface crosslinking. It is preferably 10 or less, more preferably 8 or less, and particularly preferably 7 or less.
[0031]
As the type of the organic solvent used in the surface cross-linking treatment, a conventionally known water-soluble organic solvent can be used, and the degree of penetration of the surface cross-linking agent into the inside of the polymer particles (S ′) before surface cross-linking, the surface cross-linking agent Can be appropriately selected in consideration of the reactivity and the like, and a hydrophilic organic solvent soluble in water such as methanol and diethylene glycol is preferred. Such solvents may be used alone or in combination of two or more. The amount (% by weight) of the organic solvent can be variously changed depending on the type of the solvent, but is preferably 1 to 20, more preferably 1 to 20, based on the weight of the polymer particles (S ′) before surface crosslinking. 15, particularly preferably 1 to 10. The amount (% by weight) of the organic solvent to water can be arbitrarily changed, and is preferably 20 to 80, more preferably 25 to 75, and particularly preferably 30 to 70 based on the weight of water. . That is, the use amount (% by weight) of the organic solvent with respect to water is preferably 20 or more, more preferably 25 or more, particularly preferably 30 or more, and further preferably 80 or less, more preferably 80 or less, based on the weight of water. It is 75 or less, particularly preferably 70 or less.
[0032]
The reaction temperature (° C.) of the surface crosslinking treatment is preferably from 80 to 200, more preferably from 90 to 180, particularly preferably from 100 to 160. That is, the reaction temperature (° C.) of the surface crosslinking treatment is preferably 80 or higher, more preferably 90 or higher, particularly preferably 100 or higher, and preferably 200 or lower, more preferably 180 or lower, particularly preferably 160 or lower. is there. The reaction time (minute) of the surface cross-linking treatment can be changed depending on the reaction temperature, but is preferably 3 to 60, more preferably 4 to 50, and particularly preferably 5 to 40. That is, the reaction time (minute) of the surface crosslinking treatment is preferably 3 or more, more preferably 4 or more, particularly preferably 5 or more, and preferably 60 or less, more preferably 50 or less, and particularly preferably 40 or less. is there. In addition, a crosslinked polymer obtained by surface crosslinking with a surface crosslinking agent or a water-containing resin (WA) composed of the same and water is additionally used with a surface crosslinking agent of the same type or a surface crosslinking agent of a different type from this. Surface cross-linking can also be provided.
[0033]
The thus obtained water-containing resin (WA) is crushed (minced), dried, and, if necessary, further crushed and / or adjusted in particle size to obtain crosslinked polymer particles (S). As a drying method, a usual method can be applied, for example, a method of drying with hot air at a temperature of 80 to 230 ° C, a thin film drying method using a drum dryer heated to 100 to 230 ° C, and (heating) reduced pressure. A drying method, a freeze drying method, a drying method using infrared rays, and the like can be applied. There is also no particular limitation on the pulverizing method, and a method using a hammer type pulverizer, an impact type pulverizer, a roll type pulverizer, a shet air flow type pulverizer, or the like can be applied. The pulverized material is sieved as necessary to adjust the particle size. The shape of the crosslinked polymer particles (S) after the pulverization is not particularly limited, and may be irregularly crushed, scaly, pearl, rice, granulated, tufted, tufted, and aggregates thereof. Is mentioned.
[0034]
In the case of the reversed-phase suspension radical polymerization method, if necessary, a part of the aqueous polymerization solution can be supplied to a hydrophobic organic solvent containing a dispersant to carry out suspension polymerization. In addition, the concentration (% by weight) of (meth) acrylic acid (salt) and other copolymerized vinyl monomers in the aqueous polymerization solution depends on the weight of the aqueous polymerization solution from the viewpoints of industrial productivity and absorption capacity of the crosslinked polymer particles. Is preferably from 10 to 45, more preferably from 12 to 40, and particularly preferably from 15 to 35. That is, in this case, the concentration (% by weight) of the (meth) acrylic acid (salt) and other copolymerized vinyl monomers in the aqueous polymerization solution is preferably 10 or more, more preferably 12 or more, based on the weight of the aqueous polymerization solution. It is particularly preferably at least 15, more preferably at most 45, further preferably at most 40, particularly preferably at most 35. In addition, the amount of water is preferably 90 to 65% by weight based on the weight of the aqueous polymerization solution from the viewpoint of industrial productivity and absorption capacity of the crosslinked polymer.
[0035]
As the hydrophobic organic solvent, known organic solvents can be used as long as they are hardly soluble in water, and hydrocarbons having 5 to 18 carbon atoms (pentane, cyclohexane, normal hexane, normal heptane, toluene, xylene) And octadecane). The use amount of the hydrophobic organic solvent is preferably from 10 to 90, more preferably from 20 to 80, and particularly preferably from 30 to 60, based on the total weight of the radical polymerizable monomer.
[0036]
In the case of the reversed-phase suspension radical polymerization method, known dispersants (sucrose ester, phosphate ester and sorbitan ester can be used. When a dispersant is used, the amount (% by weight) of the dispersant is as follows: Based on the total weight of the (meth) acrylic acid (salt) and other copolymerized vinyl monomers, it is preferably 0.0001 to 1, more preferably 0.005 to 0.5, and particularly preferably 0.01 to 0.3. That is, in this case, the use amount (% by weight) of the dispersant is preferably 0.0001 or more, more preferably, based on the total weight of (meth) acrylic acid (salt) and other copolymerized vinyl monomers. Is at least 0.005, particularly preferably at least 0.01, preferably at most 1, more preferably at most 0.5, particularly preferably at most 0.3.
[0037]
In the case of the reversed-phase suspension radical polymerization method, the same polymerization initiator and chain transfer agent as in the case of the aqueous solution radical polymerization method can be used. When a polymerization initiator and a chain transfer agent are used, the amounts used are the same as in the case of the water-soluble radical polymerization method, and the preferred ranges are also the same.
[0038]
In the case of the reversed-phase suspension radical polymerization method, the polymerization temperature (° C.) is not particularly limited and can be variously changed depending on the type of the polymerization initiator used, but is preferably from 10 to 100, and more preferably from 30 to 80. . That is, the polymerization temperature (° C.) is preferably 10 or more, more preferably 30 or more, and preferably 100 or less, and more preferably 80 or less.
[0039]
The size of the crosslinked polymer particles (S) is not particularly limited, but particles of 90% by weight or more (preferably 93% by weight or more, more preferably 95% by weight or more) of the total weight of the crosslinked polymer particles (S). The diameter (μm) is preferably from 37 to 1,000, more preferably from 53 to 840, particularly preferably from 105 to 840. That is, the particle size (μm) of the crosslinked polymer particles is preferably 37 or more, more preferably 53 or more, particularly preferably 105 or more, and preferably 1,000 or less, more preferably 840 or less. The weight average particle size (μm) of the crosslinked polymer particles is preferably from 200 to 700, particularly preferably from 250 to 600. That is, the weight average particle size (μm) of the crosslinked polymer particles is preferably 200 or more, more preferably 250 or more, and preferably 700 or less, particularly preferably 600 or less.
[0040]
In the present invention, the particle size can be measured using a low tap test sieve shaker and a JIS standard sieve specified in JIS Z8801-1976, Perry's Chemical Engineers Handbook, 6th edition (McGrow-Hill Book Company). , 1984, p. 21). The weight average particle size is determined by combining JIS standard sieves in the order of 840 μm, 710 μm, 500 μm, 420 μm, 350 μm, 250 μm, and 149 μm from the top, and a tray. About 50 g of the crosslinked polymer particles are placed in the 840 μm sieve at the top, and the mixture is permeated with a low tap test sieve shaker for 5 minutes. The weight of the resin particles on each sieve and the pan was weighed, and the total was taken as 100% to determine the weight fraction, and the 50% by weight particle size on a weight basis was defined as the weight average particle size.
[0041]
The absorption capacity (g / g) of the crosslinked polymer particles (S) with respect to physiological saline (0.9% by weight aqueous sodium chloride solution) is preferably 30 or more, more preferably 35 to 80, and particularly preferably 40 to 70. It is. That is, the absorption capacity (g / g) of the crosslinked polymer particles (S) with respect to physiological saline is preferably 30 or more, more preferably 35 or more, particularly preferably 40 or more, and further preferably 80 or less, particularly preferably 80 or less. Preferably it is 70 or less.
In addition, this absorption capacity is measured as follows. That is, 1.00 g of a sample adjusted to a particle size of 840 to 149 μm by a JIS standard sieve was weighed and put into a tea bag (bag of 20 cm in length and 10 cm in width) made of nylon mesh having a mesh size of 63 μm (JIS8801-1976), It is immersed in 500 ml of physiological saline (0.9% by weight aqueous sodium chloride solution) for 30 minutes. Thereafter, the tea bag is taken out of the physiological saline, suspended for 15 minutes and drained, the weight (X) is measured, and the absorption capacity (g / g) is calculated from the following equation.
(Equation 1)

[0042]
Under pressure (20 g / cm ² The crosslinked polymer particle (S) of (a) preferably has an absorption capacity (g / g) of 15 or more, more preferably 20 to 70, and particularly preferably 25 to 60. That is, under a pressurized saline solution (20 g / cm ² The crosslinked polymer particles (S) of the above) have an absorption capacity (g / g) of preferably 15 or more, more preferably 20 or more, particularly preferably 25 or more, further preferably 70 or less, and particularly preferably 60 or less. It is. The absorption capacity under pressure is measured as follows. That is, 0.10 g of a sample is weighed in a cylindrical plastic tube (inner diameter 30 mm, height 60 mm) having a nylon mesh having an opening of 63 μm (JIS8801-1976) stuck to the bottom surface, and the plastic tube is vertically placed on the nylon mesh. The sample was prepared so as to have a substantially uniform thickness, and 20 g / cm ² A weight having an outer diameter of 29.5 mm x 22 mm is placed so that the load becomes. Next, the plastic tube containing the sample and the weight was vertically immersed in a petri dish (diameter: 12 cm) containing 60 ml of a physiological saline solution (salt concentration: 0.9% by weight) with the nylon mesh side facing down, and allowed to stand. I do. After 60 minutes, the plastic tube containing the sample and the weight is weighed, and the weight of the sample absorbed by the physiological saline is calculated. The 10-fold value of the increase after immersion for 60 minutes is defined as the absorption capacity (g / g) under pressure to physiological saline.
[0043]
The surface tension (dyne / cm) of the surface modifier (M) is preferably 10 to 30, more preferably 11 to 28, particularly preferably 13 to 27, and most preferably 15 to 26. That is, the surface tension (dyne / cm) of the surface modifier (M) is preferably 10 or more, more preferably 11 or more, particularly preferably 13 or more, most preferably 15 or more, and preferably 30 or less, It is more preferably at most 28, particularly preferably at most 27, most preferably at most 26. The surface tension was measured by the ring method (25 ° C.), C.I. Hub, S .; G. FIG. Mason, Colloid & Polymer Science, 253 (1974), p. 566.
[0044]
The surface modifier (M) modifies the surface of the crosslinked polymer particle (S) by being attached (physical adsorption) or fixed (chemical bond) to the surface of the crosslinked polymer particle (S). It is for.
[0045]
The surface modifier (M) preferably has a bonding group capable of chemically bonding to the crosslinked polymer particles (S), and examples of the bonding mode include a hydrogen bond, an ionic bond, and a covalent bond. The surface modifier (M) may have not only one having one kind of bonding group but also two or more kinds of bonding groups. Having a bonding group capable of chemically bonding to the crosslinked polymer particles (S) allows the surface modifier (M) to be stably present on the surface of the crosslinked polymer particles (S). The penetration effect between the gels upon absorption is easily maintained.
[0046]
As a bonding group bonded by a hydrogen bond and / or an ionic bond, a carboxylate group ( ⁻ OOC-), a sulfonate group (-O ₃ S-), a phosphonate group ((( ⁻ O) ₂ OP-), a carboxy group (HOOC-), a sulfo group (HO ₃ S-), phosphono group ((HO) ₂ OP-), hydroxyl group (-OH), oxyalkylene group (-OA-), amino group (-NRH), oxycarbonyl group (-COO-), aminocarbonyl group (-CONH-), alkyloxy group (-OR ) And an oxycarbonylamino group (—NHCOO—). In addition, R in the parenthesis represents an alkyl group having 1 to 30 carbon atoms (preferably 1 to 10, more preferably 1 to 5) (methyl, ethyl, i-propyl, t-butyl, undecyl, octadel, eicosyl and the like). However, it may be an alkenyl group having 1 to 30 carbon atoms, an aryl group or an alkenyl group. OA represents an oxyalkylene group having 1 to 8 carbon atoms (oxymethylene, oxyethylene, oxypropylene, oxybutylene, oxyphenylethylene, and the like).
[0047]
The bonding group bonded by a covalent bond is a carboxy group (HOOC-) or a carboxylate group ( ⁻ A functional group capable of chemically reacting with and bonding to OOC-) is used. For example, an epoxy group (addition reaction with a carboxy group to form an ester bond), a hydroxyl group (esterification reaction with a carboxy group to form an ester bond), and an amino group (amidation reaction with a carboxy group to form an amide bond.) And an isocyanato group (which reacts with a carboxy group to form an amide bond via a mixed acid anhydride) and the like. Among these bonding groups, a bonding group bonded by a hydrogen bond and / or an ionic bond is preferable from the viewpoint of easiness of the reaction, and more preferably, a hydroxyl group and a carboxylate group ( ⁻ OOC-), a sulfonate group (-O ₃ S-), a phosphonate group ((( ⁻ O) ₂ OP-), a carboxy group (HOOC-), a sulfo group (HO ₃ S-) and a phosphono group ((HO) ₂ OP-), particularly preferably carboxylate, sulfonate, sulfo and carboxy, most preferably carboxylate and carboxy.
[0048]
The number (number) of bonding groups in the surface modifier (M) is preferably 1 to 20, more preferably 5 to 18, and particularly preferably 7 in the case of a bonding group bonded by hydrogen bonding and / or ionic bonding. -16, most preferably 10-15. In the case of a bonding group bonded by a covalent bond, 1 to 10 is preferable, 1 to 5 is more preferable, and 1 to 3 is particularly preferable. When the number of the bonding groups is within this range, (M) tends to be more stably and uniformly present on the surface of the crosslinked polymer particles (S).
[0049]
As the surface modifier (M) having a surface tension of 10 to 30 dynes / cm, a surface modifier (M1) containing a hydrocarbon group, a surface modifier (H) containing a hydrocarbon group having a fluorine atom ( M2) and a surface modifier (M3) containing a siloxane structure can be used. Among these, a surface modifier (M3) having a siloxane structure is preferable.
[0050]
The surface modifier (M1) containing a hydrocarbon group will be described. The carbon number of the hydrocarbon group is preferably from 3 to 20,000, more preferably from 8 to 15,000, and particularly preferably from 12 to 10,000. As the hydrocarbon group, an aliphatic hydrocarbon group, an aromatic hydrocarbon group and the like can be used. As the aliphatic hydrocarbon, an alkyl group having 3 to 20,000 (preferably 8 to 15,000, more preferably 12 to 10,000) or an alkyl group having 3 to 20,000 (preferably 8 to 15,000) is used. 000, more preferably 12 to 10,000) alkylene group, 3 to 20,000 (preferably 8 to 15,000, more preferably 12 to 10,000) alkenyl group, and 3 to 20,000 carbon atoms. 000 (preferably 8 to 15,000, more preferably 12 to 10,000) alkenylene groups and the like are used. As the aromatic hydrocarbon group, an aryl group having 6 to 20,000 (preferably 8 to 15,000, more preferably 10 to 10,000) carbon atoms, and a C6 to 30,000 (preferably 8 to 10) 15,000, more preferably 10 to 10,000) arylene groups and the like are used.
[0051]
Examples of the alkyl group include a propyl group, a butyl group, a pentyl group, a hexyl group, an octyl group, a dodecyl group, a stearyl group, an eicosyl group, and a triacontyl group. Examples of the alkylene group include a propylene group, a butylene group, a hexylene group, an octylene group, a dodecylene group, an octadecylene group, an eicosylene group, and a polyethylene (having 4 to 20,000 carbon atoms, preferably 8 to 15,000, more preferably 12 to 15,000 carbon atoms). Hydrocarbon groups obtained by removing two hydrogen atoms from polypropylene (6 to 20,000, preferably 9 to 15,000, more preferably 12 to 10,000). Examples of the alkenyl group include a propenyl group, a butenyl group, a pentenyl group, a hexenyl group, an octenyl group, a dodecenyl group, an octadecenyl group, an eicosenyl group, and a triacontenyl group. Examples of the alkenylene group include, for example, a propenylene group, a butenylene group, a hexenylene group, an octenylene group, a dodecenylene group, an octadecenylene group, an eicosenylene group, a tricontenenylene group, and a thermal degradation product of polyethylene (having 4 to 20,000 carbon atoms, preferably 8 to 2000 carbon atoms). 2 hydrogen atoms from 15,000, more preferably 12 to 10,000) or a thermally degraded product of polypropylene (C6 to 20,000, preferably 9 to 15,000, more preferably 12 to 10,000). And the like. The heat-reducible material is obtained by heat-treating polyethylene or polypropylene to introduce an unsaturated double bond.
[0052]
Examples of the aryl group include a phenyl group, a benzyl group, an ethylphenyl group, a tetradecylphenyl group, a nonylphenyl group, a dimethylphenyl group, a diethylphenyl group, a diheptylphenyl group, a dinonylphenyl group, a dinonylphenylphenyl group, Examples include a tolyl group, a mesityl group, a cumenyl group, a tolyl group, a xylyl group, a naphthyl group, an anthryl group and a phenanthryl group.
Examples of the arylene group include a phenylene group, an ethylphenylene group, a tetradecylphenylene group, a nonylphenylene group, a dimethylphenylene group, a diethylphenylene group, a diheptylphenylene group, a dinonylphenylene group, a dinonylphenylphenylene group, a tolylene group, Examples include a mesitylene group, a cumenylene group, a tolylene group, a xylylene group, a naphthylene group, an anthrylene group, a phenanthrylene group, and a residue of bisphenol (bisphenol, bisphenol A, bisphenol F, etc.) excluding a phenolic hydroxyl group. Among these, an aliphatic hydrocarbon group is preferable from the viewpoint of a lower surface tension, more preferably an alkyl group, an alkylene group, an alkenyl group and an alkenylene group, and particularly preferably a pentyl group, a hexyl group, an octyl group, and a dodecyl group. , Stearyl group, triacontyl group, octylene group, dodecylene group, hydrocarbon group obtained by removing two hydrogen atoms from polyethylene or polypropylene, carbonization obtained by removing two hydrogen atoms from heat degraded product of polyethylene or polypropylene. Hydrogen group, particularly preferably octyl group, dodecyl group, stearyl group, triacontyl group, dodecylene group, hydrocarbon group obtained by removing two hydrogen atoms from polyethylene or polypropylene, thermal degradation product of polyethylene or thermal degradation product of polypropylene Hydrocarbon group obtained by removing two hydrogen atoms from Or dodecyl group, stearyl group, triacontyl group, a hydrocarbon group obtained by removing two hydrogen atoms from polyethylene or polypropylene, or a hydrocarbon group obtained by removing two hydrogen atoms from a thermally degraded product of polyethylene or polypropylene. It is.
[0053]
Examples of the surface modifying agent (M1) containing a hydrocarbon group include the following (1) to (13).
(1) Examples of those having a carboxylate group as the binding group include sodium octanecarboxylate, sodium octanedicarboxylate, sodium undecanoate, sodium octadecanoate and sodium triacontancarboxylate.
(2) Examples of those having a sulfonate group as the bonding group include sodium octanesulfonate and sodium dodecylbenzenesulfonate.
(3) Examples of those having a phosphonate group as a bonding group include sodium triacontanphosphonate.
(4) Examples of those having a carboxy group as the bonding group include octanecarboxylic acid, octanedicarboxylic acid, undecanoic acid, octadecanoic acid, and triacontancarboxylic acid.
(5) Examples of the compound having a sulfo group or a phosphono group as the bonding group include octylsulfonic acid, dodecylbenzenesulfonic acid, and tricontylphosphonic acid.
(6) Examples of those having a hydroxyl group as a bonding group (having no oxyalkylene group) include octyl alcohol, octylene diol, triacontyl alcohol, octenyl alcohol, triaconenyl alcohol and octenylene diol. Can be
(7) Examples of the compound having an oxyalkylene group as a bonding group include octyl alcohol ethylene oxide (1 to 20) adduct, octylene diol ethylene oxide (1 to 20) adduct, and tricontyl alcohol ethylene oxide (1 To 20) adduct, octenyl alcohol ethylene oxide (1 to 20) adduct, triacontenyl alcohol ethylene oxide (1 to 20) adduct and octenylene diol ethylene oxide (1 to 20) adduct And those having an alkyloxy group such as those in which these terminal hydroxyl groups have been converted to an alkyloxy group having 1 to 4 carbon atoms or an alkylcarboxyl group.
(8) Examples of those having an amino group as a binding group include octylamine, dioctylamine, triacontylamine, triacontylmethylamine, octylenediamine, octylethylamine, and nonylethylamine.
(9) Examples of those having an oxycarbonyl group as a bonding group include octyl propane carboxylate, nonyl propane carboxylate, ethyl octane carboxylate, and ethyl nonane carboxylate. (10) Examples of the compound having an aminocarbonyl group as the bonding group include N-octylpropanecarboxylic acid amide, N-nonylpropanecarboxylic acid amide, N-propyloctanoic acid amide, and N-ethylundecanoic acid amide.
(11) Examples of those having an oxycarbonylamino group as a bonding group include octyloxycarbonylaminoethane, nonyloxycarbonylaminoethane, octylaminocarbonyloxyethane, and nonylaminocarbonyloxyethane.
(12) Examples of those having an epoxy group as a bonding group include octyl glycidyl ether, octylene diglycidyl ether, and triacontyl glycidyl ether.
(13) Examples of the compound having an isocyanate group as the bonding group include octyl isocyanate and nonyl isocyanate.
[0054]
Among these (1) to (13), (1) those having a carboxylate group as a bonding group, (2) those having a sulfonate group as a bonding group, (4) those having a carboxy group as a bonding group, 5) Those having a sulfo group or a phosphono group as a bonding group and those having an amino group as a bonding group (8) are more preferable, and (1), (2) and (8) are more preferable, and (8) is particularly preferable. is there.
[0055]
The surface modifier (M2) containing a hydrocarbon group having a fluorine atom will be described. The number of fluorine atoms in the hydrocarbon group is preferably 3 to 60, more preferably 10 to 50, and particularly preferably 15 to 40. The number of carbon atoms is preferably 1 to 30, more preferably 5 to 25, and particularly preferably 8 to 20. As the hydrocarbon group having a fluorine atom, a fluorine-containing aliphatic hydrocarbon group, a fluorine-containing aromatic hydrocarbon group, and the like can be used.
[0056]
Examples of the fluorine-containing aliphatic hydrocarbon group include perfluoroalkyl groups (1 to 30, preferably 5 to 25, more preferably 8 to 20) and perfluoroalkyl (1 to 30 carbon atoms, preferably 5 to 25 carbon atoms). , More preferably 8-20) -alkylene group (1-20 carbon atoms, preferably 1-10, more preferably 2-8), perfluoroalkylene group (1-30 carbon atoms, preferably 5-25, more Preferably 8 to 20), a perfluoroalkenyl group (3 to 30 carbon atoms), a perfluoroalkenylene group (3 to 30 carbon atoms) and the like.
As the fluorine-containing aromatic hydrocarbon group, a perfluoroaryl group (C6 to C30), a perfluoroarylene group (C6 to C30) and the like are used.
[0057]
Examples of the perfluoroalkyl group include a trifluoromethyl group, a pentafluoroethyl group, a pentafluoropropyl group (such as a pentafluoroethylmethyl group), a heptafluoropropyl group, a heptafluorobutyl group (such as a heptafluoromethyl group), and a nonafluorohexyl group. Groups (such as a nonafluorobutylethyl group), a tridecafluorooctyl group (such as a tridecafluorohexylethyl group), and a heptadecafluorododecyl group (such as a heptadecafluorooctylbutyl group). Examples of the perfluoroalkylalkylene group include a pentafluoroethyl-ethylene group, a heptafluoropropyl-ethylene group, a nonafluorobutyl-ethylene group, a tridecafluorohexyl-ethylene group, and a heptadecafluorooctyl-ethylene group. . Examples of the perfluoroalkylene group include a difluoromethylene group, a tetrafluoroethylene group, a hexafluoropropylene group, an octafluorobutylene group, a dodecafluorohexylene group, a hexadecafluorooctylene group, and a tetracosafluorododecylene group. No. Examples of the perfluoroalkenyl group include a pentafluoropropenyl group, a heptafluorobutenyl group, a nonafluoropentenyl group, an undecafluorohexenyl group, a pentadecaoctenyl group, a tricosadodecenyl group, and a nonapentacontafluorotriaconte group. And the like.
Examples of the perfluoroalkenylene group include, for example, a tetrafluoropropenylene group, a hexafluorobutenylene group, a decafluorohexenylene group, a tetradecafluorooctenylene group, a docosafluorododecenylene group, and an octapentacontafluorotriconenylene group And the like. Examples of the perfluoroaryl group include, for example, a pentafluorophenyl group, a heptafluoromethylphenyl group, a nonafluoroethylphenyl group, a tritriacontafluorotetradecylphenyl group, a nonafluorodimethylphenyl group, a tridecafluorodiethylphenyl group and a tritoria And a contafluorodiheptylphenyl group. Examples of the perfluoroarylene group include, for example, a tetrafluorophenylene group, a hexafluoromethylphenylene group, an octafluoroethylphenylene group, a ditriacontafluorotetradecylphenylene group, an octafluorodimethylphenylene group, a dodecafluorodiethylphenylene group, and a ditriacontaline group. And a fluorodiheptylphenylene group.
[0058]
Among these, from the viewpoint of surface tension, a fluorine-containing aliphatic hydrocarbon group is preferred, more preferably a perfluoroalkyl group, a perfluoroalkyl-alkylene group and a perfluoroalkylene group, and particularly preferably a perfluoroalkyl group and Perfluoroalkylalkylene groups, most preferably perfluoroalkyl. Among the perfluoroalkyl groups, a heptafluoropropyl group, a heptafluorobutyl group, a nonafluorohexyl group, a tridecafluorooctyl group and a heptadecafluorododecyl group are preferable, and a heptafluoropropyl group and a heptafluorobutyl group are more preferable. And particularly preferably a heptafluorobutyl perfluoroalkyl group.
[0059]
Examples of the surface modifier (M2) containing a hydrocarbon group having a fluorine atom include the following (14) to (26).
(14) Examples of those having a carboxylate group as the binding group include sodium nonafluorohexanecarboxylate and disodium dodecafluorohexanedicarboxylate.
(15) Examples of those having a sulfonate group as the binding group include sodium nonafluorohexanesulfonate and disodium dodecafluorohexanedisulfonate.
(16) Examples of those having a phosphonate group as the binding group include sodium nonafluorohexanephosphonate and disodium dodecafluorohexanediphosphonate.
(17) Examples of those having a carboxy group as the bonding group include nonafluorohexanecarboxylic acid and dodecafluorohexanedicarboxylic acid.
(18) Examples of the compound having a sulfo group or a phosphono group as the bonding group include nonafluorohexylsulfonic acid and nonafluorohexylphosphonic acid.
(19) Examples of those having a hydroxyl group as a bonding group include nonafluorohexanol and dodecafluorohexanol.
(20) Examples of those having an amino group as a bonding group include nonafluorohexylamine, di (nonafluorohexyl) amine, dodecafluorohexylenediamine, tetracosafluorododecylenediamine, decafluorohexenylamine, and nonafluorohexylethylamine And dodecafluorohexylethylamine.
(21) Examples of those having an oxycarbonyl group as the bonding group include methyl nonafluorohexanecarboxylate, dimethyl dodecafluorohexanedicarboxylate, nonafluorohexyl acetate, dodecafluorohexyl acetate, and the like.
(22) Examples of the compound having an aminocarbonyl group as a bonding group include N-methylnonafluorohexanoic acid amide, N-methyldodecafluorohexanoic acid amide, N-hexyltrifluoroacetamide, N-methyltrifluoroacetamide and the like. .
(23) Examples of those having an alkyloxy group as a bonding group include nonafluorohexylethyl ether and 2-pentafluoroethylhexylmethyl ether
Dodecafluorohexyl methyl ether and dodecafluorohexyl ethyl ether;
(24) Examples of those having an aminocarbonyloxy group as the bonding group include nonafluorohexyloxycarbonylaminoethane and dodecafluorohexyloxycarbonylaminoethane.
(25) Examples of those having an epoxy group as a bonding group include nonafluorohexyl glycidyl ether and dodecafluorohexylene glycidyl ether.
(26) Examples of the compound having an isocyanato group as the bonding group include isocyanatononafluorohexane and isocyanatododecafluorohexane.
[0060]
Of these (14) to (26), (14) those having a carboxylate group as a bonding group, (15) those having a sulfonate group as a bonding group, (17) those having a carboxy group as a bonding group, 18) Those having a sulfo group or a phosphono group as the linking group and those having an amino group as the (20) linking group are preferable, more preferably (14), (15) and (20), particularly preferably (20). is there.
[0061]
The surface modifier (M3) having a siloxane structure will be described.
Examples of the surface modifier (M3) having a siloxane structure include polyether-modified silicone oils (such as polyethylene oxide-modified silicone and polyethylene oxide / polypropylene oxide-modified silicone), carboxyl-modified silicone oil, alkyl-modified silicone oil, and epoxy-modified silicone oil. , An amino-modified silicone oil and an alkoxy-modified silicone oil. As the polyether-modified silicone oil, polyethylene oxide-modified silicone and polyethylene oxide / polypropylene oxide-modified silicone can be used. For example, products manufactured by Shin-Etsu Chemical: KF-351, KF-352, KF-353, and KF-615A And products manufactured by Dow Corning Toray Silicone Co., Ltd .: BY-16-004, SH3746 and SF8410. Examples of the carboxyl-modified silicone oil include products manufactured by Shin-Etsu Chemical Co., Ltd .: X-22-162C, X-22-3701E, and X-22-3710, and products manufactured by Dow Corning Toray Silicone: BY-16-750. And SF8418. Examples of the alkyl-modified silicone oil include KF-412, KF-413, and KF-414 manufactured by Shin-Etsu Chemical Co., Ltd., and SH203, SH230, and SF8416 manufactured by Dow Corning Toray Silicone Co., Ltd.
Examples of epoxy-modified silicone oils include products manufactured by Shin-Etsu Chemical Co., Ltd .: KF-105, X-22-163A, X-22-163C, KF-1001 and X-22-169B, and Dow Corning Toray Silicone Co., Ltd. Products: BY16-855D, SF8411, BY16-839 and SF8421. As amino-modified silicone oils, products manufactured by Shin-Etsu Chemical: KF-880, KF-885, KF-867, KF-8003 and KF-8004, and products manufactured by Toray Dow Corning Silicone: BY-16 -853C, BY16-208, BY16-209, BY16-850, and BY16-872. Examples of the alkoxy-modified silicone oil include KF-857, KF-862, and KF-8001 manufactured by Shin-Etsu Chemical Co., Ltd. Among these (M3), polyether-modified silicone oil is preferred from the viewpoint of acquisition cost and the like, and polyethylene oxide-modified silicone is more preferred.
[0062]
The viscosity (cSt) at 25 ° C. of the surface modifier (M) is from 10 to 2,000 from the viewpoint of uniform mixing with the crosslinked polymer particles (S), permeability into (S), and the like. It is more preferably 15 to 1,500, particularly preferably 20 to 1,000. That is, the viscosity (cSt) at 25 ° C. of the surface modifier (M) is preferably 10 or more, more preferably 15 or more, particularly preferably 20 or more, and preferably 2,000 or less, more preferably 1 or less. , 500 or less, particularly preferably 1,000 or less.
[0063]
Two or more of these surface modifiers (M) can be used in combination. The surface modifier (M) may be used in a form dissolved or emulsified in water or a volatile solvent. As the volatile solvent, those having a vapor pressure at 20 ° C. of 17.5 to 700 mmHg are preferable, more preferably 20 to 600 mmHg, and particularly preferably 30 to 500 mmHg. That is, the vapor pressure (mmHg) at 20 ° C. of the volatile solvent is preferably 17.5 or more, more preferably 20 or more, particularly preferably 30 or more, and preferably 700 or less, more preferably 600 or less. Or less, particularly preferably 500 or less. Volatile solvents include alcohols (such as methanol, ethanol and isopropyl alcohol), hydrocarbons (such as hexane, cyclohexane and toluene), ethers (such as diethyl ether and tetrahydrofuran), ketones (such as acetone and methyl ethyl ketone), and esters (such as ethyl acetate). Isopropyl acetate and diethyl carbonate). When water or a volatile solvent is used, the amount (% by weight) thereof is preferably from 1 to 900, more preferably from 5 to 700, and particularly preferably from 10 to 400, based on the weight of (B). . That is, in this case, the amount (% by weight) of these used is preferably 1 or more, more preferably 5 or more, particularly preferably 10 or more, and preferably 900 or less, based on the weight of (B). It is preferably at most 700, particularly preferably at most 400. When water and a volatile solvent are used, the amount of water (% by weight) is preferably 50 to 98, more preferably 60 to 95, and particularly preferably 70 to 90, based on the weight of the water and the volatile solvent. It is. That is, it is preferably 50 or more, more preferably 60 or more, particularly preferably 70 or more, and preferably 98 or less, more preferably 95 or less, and particularly preferably 90 or less.
[0064]
The HLB of the surface modifier (M) is preferably 7 to 18, more preferably 8 to 18, and particularly preferably 10 to 18. In addition, HLB means a hydrophilic-hydrophobic balance (HLB) value, and the Oda method (Synthesis of surfactant and its application, page 501, Maki Shoten, Oda, Teramura; Introduction of new surfactant, page 197) Takehiko Fujimoto, Sanyo Chemical Industries, Ltd.).
[0065]
The amount (% by weight) of the surface modifier (M) used is preferably 0.001 to 3, more preferably 0.005 to 2, and particularly preferably 0, based on the weight of the crosslinked polymer particles (S). 0.07 to 1.5, most preferably 0.1 to 1.0. That is, the amount (% by weight) of the surface modifier (M) used is preferably 0.001 or more, more preferably 0.005 or more, and particularly preferably 0, based on the weight of the crosslinked polymer particles (S). 0.07 or more, most preferably 0.1 or more, and preferably 3 or less, more preferably 2 or less, particularly preferably 1.5 or less, and most preferably 1.0 or less. If it is less than this range, a difference in effect from the water-absorbing polymer particles not treated with the surface modifier (M) is unlikely to appear, and if it exceeds this range, the powder fluidity tends to be unfavorable.
[0066]
The water-absorbing polymer particles (X) may be composed of the crosslinked polymer particles (S) and the surface modifier (M), and (M) must exist near the surface of the crosslinked polymer particles (S). Preferably, after polymerization of the crosslinked polymer particles (S), the crosslinked polymer particles (S) and (M) are mixed and treated. When the crosslinked polymer particles (S) are obtained by aqueous solution polymerization, the timing of mixing and treating the surface modifier (M) is not particularly limited. However, during the polymerization step, immediately after the polymerization step, crushing of the water-containing resin (WA) is performed. (Minch), immediately before the surface crosslinking treatment step, during the surface crosslinking treatment step, immediately after the surface crosslinking treatment step, and during the drying step. Among them, from the viewpoint of uniformly treating the particle surface of the crosslinked polymer particles (S), immediately after the polymerization step, during the crushing (mincing) step of the water-containing resin (WA), immediately before the surface crosslinking step, and during the surface crosslinking step Preferably, immediately after the surface cross-linking treatment step and during the drying step, and more preferably immediately after the polymerization step, and more preferably immediately after the polymerization step, from the viewpoint of the ease of bonding between the bonding group in the surface modifier (M) and the crosslinked polymer particles (S). During the crushing (mincing) of the resin (WA), immediately before the surface crosslinking treatment step, during the surface crosslinking treatment step and immediately after the surface crosslinking treatment step, particularly preferably immediately before the surface crosslinking treatment step, during the surface crosslinking treatment step and immediately after the surface crosslinking treatment step is there.
[0067]
When crosslinked polymer particles (S) are obtained by reverse phase suspension polymerization, the timing of mixing and treating the surface modifier (M) is not particularly limited, but may be during the polymerization step, immediately after the polymerization step, or during the dehydration step ( (During the step of dehydration to about 10% by weight of water), immediately after the dehydration step, during the step of separating the water-absorbent resin particles (S) obtained by polymerization from the organic solvent used in the polymerization, immediately before the surface crosslinking treatment step, and immediately before the surface crosslinking. During the treatment step, immediately after the surface cross-linking treatment step and during the drying step (step of drying to 10% by weight or less) and the like. Of these, from the viewpoint of uniformly treating the particle surface of the crosslinked polymer particles (S), the water-absorbent resin particles (S) obtained by the polymerization are used for polymerization immediately after the polymerization step, during the dehydration step, immediately after the dehydration step. During the step of separating the organic solvent from the organic solvent, immediately before the surface cross-linking step, during the surface cross-linking step, immediately after the surface cross-linking step, and during the drying step. From the viewpoint of easiness of bonding with (S), more preferably, immediately after the polymerization step, during the dehydration step, immediately after the dehydration step, the water-absorbent resin particles (S) obtained by the polymerization are separated from the organic solvent used for the polymerization. During the step, immediately before the surface cross-linking step, during the surface cross-linking step and immediately after the surface cross-linking step, particularly preferably during the dehydration step, immediately before the surface cross-linking step, during the surface cross-linking step and immediately after the surface cross-linking step.
[0068]
That is, the step of mixing and treating the crosslinked polymer particles (S) and the surface modifier (M) may be performed at any stage, but is preferably performed before, during or after the removal of water from the water-containing resin. From the viewpoint of the ease of bonding between the bonding group in the surface modifier (M) and the crosslinked polymer particles (S), it is more preferable that the water-containing resin has a water content of 10% by weight or more, ie, water removal. It is the stage before or during the removal.
[0069]
As a method of mixing and treating the crosslinked polymer particles (S) and the surface modifier (M), (M) is preliminarily crosslinked at a high concentration (for example, 5 to 20% by weight based on the crosslinked polymer particles) at room temperature. A masterbatch is prepared by adding to the polymer particles (S) and mixing for 10 minutes or more, and the masterbatch is added to the crosslinked polymer particles (S) at room temperature so as to have a predetermined addition amount as (M). Examples include a method of mixing and treating for 10 minutes or more, and a method of adding or spraying (M) at room temperature while stirring the crosslinked polymer particles (S), or mixing and treating by spraying. An industrial apparatus for mixing and treating the crosslinked polymer particles (S) and the surface modifier (M) is not particularly limited, and examples thereof include a conical blender, a Nauter mixer, a double arm kneader, and a V-type kneader. Mechanical mixers such as a mixer, a fluidized bed mixer, a turbulizer, a screw type line blender, a ribbon mixer and a mortar mixer are preferably used.
[0070]
When the viscosity of the surface modifier (M) is 1,000 to 2,000 cSt or higher, the crosslinked polymer particles (S) and / or the surface modifier (M) are heated (preferably at 30 to 200 ° C, The temperature of the crosslinked polymer particles (S) and (M) can be mixed and treated after further preferably 40 to 160 ° C, particularly preferably 50 to 120 ° C. That is, in this case, the heating temperature (° C.) of the crosslinked polymer particles (S) and / or the surface modifier (M) is preferably 30 or more, more preferably 40 or more, particularly preferably 50 or more, It is preferably at most 200, more preferably at most 160, particularly preferably at most 120.
[0071]
When the crosslinked polymer particle (S) is a surface crosslinked agent and is a crosslinked polymer particle having a surface crosslinked treatment in the vicinity of the surface of the particle, (M) is added to the surface crosslinked agent (or this solution). You may leave. When the bonding mode of the bonding group of the surface modifier (M) is mainly covalent, it is preferable to mix the crosslinked polymer particles (S) and (M) and then provide a heating step to perform a heating reaction. . The heating temperature (° C.) is preferably from 80 to 200, more preferably from 90 to 160, and particularly preferably from 100 to 140. That is, the heating temperature (° C.) is preferably 80 or higher, more preferably 90 or higher, particularly preferably 100 or higher, and is preferably 200 or lower, more preferably 160 or lower, particularly preferably 140 or lower. The reaction time (minute) can be changed depending on the reaction temperature, but is preferably 3 to 60, more preferably 5 to 40, and particularly preferably 8 to 30. That is, the reaction time (minute) is preferably 3 or more, more preferably 5 or more, particularly preferably 8 or more, and preferably 60 or less, more preferably 40 or less, and particularly preferably 30 or less. When the bonding mode of the bonding group of the surface modifier (M) is mainly hydrogen bonding or mainly ionic bonding, it is not necessary to particularly provide a heating step after mixing the crosslinked polymer and (M).
[0072]
The surface tension (dynes / cm) of the surface modifier (N) is preferably 40 to 80, more preferably 40 to 75, particularly preferably 40 to 70, and most preferably 40 to 65. The surface modifier (N) modifies the surface of the crosslinked polymer particle (S) by being attached (physical adsorption) or fixed (chemical bond) to the surface of the crosslinked polymer particle (S). It is for. The surface modifier (N) preferably has a bonding group capable of chemically bonding to the crosslinked polymer particles (S), and examples of the bonding method include a hydrogen bond, an ionic bond, and a covalent bond. In addition, the surface modifier (N) may have not only one having one kind of bonding group but also two or more kinds of bonding groups. Having a bonding group capable of chemically bonding to the crosslinked polymer particle (S) allows the surface modifier (N) to be stably present on the surface of the crosslinked polymer particle (S), so that penetration between the gels upon water absorption The effect lasts.
[0073]
The bonding group is the same as the bonding group of the surface modifier (M). Of these bonding groups, from the viewpoint of easiness of the reaction, a bonding group bonded by a hydrogen bond and a bonding group bonded by an ionic bond. Groups, more preferably a hydroxyl group, a carboxylate ( ⁻ OOC-), sulfonate (-O ₃ S-) and phosphonates (( ⁻ O) ₂ OP-) and the like.
[0074]
The number (number) of bonding groups in the surface modifier (N) is preferably 1 to 20, more preferably 5 to 18, particularly preferably 7 to 16, and most preferably 10 to 15. When the number of bonding groups is in this range, the surface modification (N) tends to be more easily and stably and uniformly present on the surface of the crosslinked polymer particles (S).
[0075]
The surface modifier (N) includes a surface modifier (N1) having a polyoxyalkylene group, a polycation (N2), a polyanion (N3), and the like. Among these, the surface modifier (N1) having a polyoxyalkylene group is preferred.
[0076]
Examples of the polyoxyalkylene group include a polyoxyethylene group, a polyoxyethylene polyoxypropylene (block copolymer) group, and a polyoxytetramethylene group. The degree of polymerization of these polyoxyalkylene groups is 3 to 1000, preferably 5 to 100, more preferably 10 to 50, and particularly preferably 20 to 25. That is, this degree of polymerization is 3 or more, preferably 5 or more, more preferably 10 or more, particularly preferably 20 or more, and 1000 or less, preferably 100 or less, more preferably 50 or less, and particularly preferably. 25 or less.
[0077]
Examples of the surface modifier (N1) having a polyoxyalkylene group include the following (27) to (37).
(27) Examples of those having a carboxylate group as the binding group include sodium poly (oxyethylene) propionate and sodium poly (oxyethylene) acetate.
(28) Examples of the compound having a sulfonate group as the binding group include sodium poly (oxyethylene) sulfonate.
(29) Examples of those having a phosphonate group as a binding group include sodium poly (oxyethylene) phosphonate.
(30) Examples of those having a carboxy group as the binding group include poly (oxyethylene) propionic acid and poly (oxyethylene) acetic acid.
(31) Examples of those having a sulfo group or a phosphono group as the bonding group include poly (oxyethylene) sulfonic acid and poly (oxyethylene) phosphonic acid.
(32) Examples of those having an amino group as a bonding group include poly (oxyethylene) ethylamine, bis (poly (oxyethylene)) ethylamine, and tris (poly (oxyethylene)) ethylamine.
(33) Examples of those having a carbonyloxy group as the bonding group include poly (oxyethylene) carbonyloxyethane and poly (oxyethylene) carbonyloxyethane.
(34) Examples of the compound having an aminocarbonyl group as the bonding group include N-polyoxyethylene-N-ethylpropanecarboxamide and N-polyoxyethylene-N-propylpropanamide.
(35) Examples of those having an alkyloxy group as a bonding group include poly (oxyethylene) dimethyl ether, polyoxyethylene diethyl ether, methyloxy poly (oxyethylene) acetate, and methyloxy poly (oxyethylene) undecyl ether. No.
(36) Examples of those having an epoxy group as a bonding group include polyoxyethylene monoglycidyl ether, methyloxy polyoxyethylene glycidyl ether, and polyoxyethylene diglycidyl ether.
(37) Examples of the compound having an isocyanate group as the bonding group include poly (ethyleneoxy) ethyl isocyanate.
[0078]
Of these (27) to (37), (27) those having a carboxylate group as a bonding group, (28) those having a sulfonate group as a bonding group, and (29) those having a carboxy group as a bonding group , (30) those having a sulfo group or a phosphono group as a bonding group and (31) those having an amino group as a bonding group, more preferably (27), (28) and (31), and particularly preferably (31) ).
[0079]
Examples of the polycation (N2) include a polymer having a quaternary ammonium group, a quaternary salt of polymethylene polyamine, and the like. Examples of the polymer having a quaternary ammonio group include polymers having a structure including a quaternary ammonio group-containing radically polymerizable monomer as an essential constituent unit. As the quaternary ammonium group-containing radical polymerizable monomer, an ammonium salt having 6 to 30 carbon atoms or the like can be used, and trimethylpropenyl ammonium hydroxide, trimethylaminoethyl (meth) acrylate chloride, methyldiethylaminoethyl (meth) acrylate -Methosulfate, trimethylaminoethyl (meth) acrylamide chloride, diethylbenzylaminoethyl (meth) acrylamide chloride, and the like. The weight average molecular weight of the polymer having a quaternary ammonium group is preferably 500 or more, more preferably 5,000 or more, particularly preferably 10,000 or more, and preferably 1,000,000 or less, more preferably 50,000 or less, and particularly preferably. 20,000 or less. The radical polymerizable monomer to be copolymerized is not particularly limited, but may be (meth) acrylamide, N-alkyl (1-8 carbon atoms) (meth) acrylamide (N-methylacrylamide, etc.), N, N-dialkyl (carbon number 1-8) (meth) acrylamide (such as N, N-dimethylacrylamide and N, N-di-n- or i-propylacrylamide) and N-hydroxyalkyl (having 1 to 8 carbon atoms) (meth) acrylamide. Can be Examples of the quaternary salt of polymethylene polyamine include N, N ,, N ', N'-tetramethyltetramethylenediamine dichloride. Among these, a polymer having a quaternary ammonium group is preferable, and a polymer having a quaternary ammonium group using trimethylpropenyl ammonium hydroxide or trimethylaminoethyl (meth) acrylate chloride is more preferable.
[0080]
Examples of the polyanion (N3) include a radical polymer of a radical polymerizable monomer having a carboxylate, a radical polymer of a radical polymerizable monomer having a sulfonate, and a radical polymer of a radical polymerizable monomer having a phosphonate. The weight average molecular weight of the polyanion is preferably at least 500, more preferably at least 5,000, particularly preferably at least 10,000, and preferably at most 1,000,000, more preferably at most 50,000, particularly preferably at most 20,000. Examples of the radically polymerizable monomer monomer having a carboxylate include unsaturated monocarboxylates having 3 to 10 carbon atoms (such as sodium (meth) acrylate, sodium crotonate and potassium cinnamate), and unsaturated unsaturated carboxylic acids having 4 to 10 carbon atoms. And dicarboxylates such as sodium maleate, sodium fumarate, potassium citraconic acid and sodium itaconate. Examples of the radical polymerizable monomer monomer having a sulfonate include a vinyl sulfonate having 3 to 10 carbon atoms (such as sodium (meth) allyl sulfonate, sodium styrene sulfonate, and sodium α-methylstyrene sulfonate); (Meth) acryloyloxyalkyl sulfonates such as sodium (meth) acryloxypropanesulfonate, sodium 2-hydroxy-3- (meth) acryloxypropanesulfonate and sodium 2- (meth) acryloxyethanesulfonate) And a (meth) acryloylaminoalkyl sulfonate having 5 to 10 carbon atoms {sodium 2- (meth) acryloylamino-2,2-dimethylethanesulfonate, sodium 2- (meth) acrylamino-2-methylpropanesulfonate And 3- ( Data) acrylic amino-2-hydroxy-propane sulfonate and the like} and the like. Examples of the radical polymerizable monomer having a sulfonate group include alkyl (meth) acrylates having 5 to 10 carbon atoms (alkyl having 2 to 6 carbon atoms) phosphonates such as sodium 2-acryloyloxyethyl phosphonate. . Among these polyanions, a radical polymer of a radical polymerizable monomer having a carboxylate and a radical polymer of a radical polymerizable monomer having a sulfonate are preferred, and more preferably a radical polymer of a radical polymerizable monomer having a carboxylate. Of the radical polymerizable monomers having a carboxylate, sodium (meth) acrylate is preferred.
[0081]
The viscosity (cSt) at 25 ° C. of the surface modifier (N) is from 10 to 2,000 from the viewpoint of uniform mixing with the crosslinked polymer particles (S), permeability into (S), and the like. It is preferably from 15 to 1,500, more preferably from 20 to 1,000. That is, the viscosity (cSt) at 25 ° C. of the surface modifier (N) is preferably 10 or more, more preferably 15 or more, particularly preferably 20 or more, and preferably 2,000 or less, more preferably 1 or less. , 500 or less, particularly preferably 1,000 or less.
[0082]
Two or more of these surface modifiers (N) can be used in combination. The surface modifier (N) can be used in a form dissolved or emulsified in water or a volatile solvent.
As the volatile solvent, those similar to the surface modifier (M) can be used, and the preferable range and the like are also the same.
[0083]
The amount (% by weight) of the surface modifier (N) is preferably 0.001 to 3, more preferably 0.005 to 2, and particularly preferably 0, based on the weight of the crosslinked polymer particles (S). 0.07 to 1.5, most preferably 0.1 to 1.0. That is, the amount (% by weight) of the surface modifier (N) used is preferably 0.001 or more, more preferably 0.005 or more, and particularly preferably 0, based on the weight of the crosslinked polymer particles (S). 0.07 or more, most preferably 0.1 or more, and preferably 3 or less, more preferably 2 or less, particularly preferably 1.5 or less, and most preferably 1.0 or less. If it is less than this range, there is little difference in effect from the water-absorbing polymer particles (S) that have not been treated with the surface modifier (N). If it exceeds this range, it tends to be unfavorable in terms of powder fluidity. is there.
[0084]
The crosslinked polymer particle (Y) may be composed of the crosslinked polymer particle (S) and the surface modifier (N), but (N) may be present near the surface of the crosslinked polymer particle (S). Preferably, after the polymerization of the crosslinked polymer particles (S), the crosslinked polymer particles (S) and (N) are mixed and treated. The step and method of mixing and treating the crosslinked polymer particles (S) and the surface modifier (N) to obtain the crosslinked polymer particles (Y) include the steps of mixing the crosslinked polymer particles (S) and the surface modifier (M). ) Can be applied and the same steps and methods as those for obtaining the crosslinked polymer particles (X) by mixing and treating with the above are also preferable.
[0085]
When the viscosity of the surface modifier (N) is 1,000 to 2,000 cSt or more, the crosslinked polymer particles (S) and / or the modifier (N) are heated (preferably at 30 to 200 ° C., (40-160 ° C, particularly preferably 50-120 ° C), and then the crosslinked polymer particles (S) and (M) can be mixed and treated. That is, in this case, the heating temperature (° C.) of the crosslinked polymer particles (S) and / or the modifier (N) is preferably 30 or more, more preferably 40 or more, particularly preferably or more, and 200 or less. It is more preferably 160 or less, particularly preferably 120 or less. When the crosslinked polymer particle (S) is a crosslinked polymer particle (S) having a surface crosslinker and a surface cross-linking treatment performed near the surface of the particle, a surface modifier is included in the surface crosslinker (or this solution). (N) may be added.
When the bonding mode of the bonding group of the surface modifier (N) is mainly a covalent bond, the step of reacting the crosslinked polymer with (N), the heating temperature and the reaction time are different from those of the surface modifier (M). The same applies, and the preferred range is also the same.
[0086]
The crosslinked polymer particles (X) and the crosslinked polymer particles (Y) are obtained by subjecting the crosslinked polymer particles (S) to a surface treatment with a surface modifier (M) or a surface modifier (N). The crosslinked polymer (S) used for the polymer particles (X) and the crosslinked polymer particles (S) used for the crosslinked polymer particles (Y) may be the same or different. As a different case, the method for producing the crosslinked polymer particles (S) used for the crosslinked polymer particles (X) is a suspension polymerization method, and the crosslinked polymer particles (S) used for the crosslinked polymer particles (Y) are used. )) Is an aqueous solution polymerization method.
[0087]
The absorption capacity (g / g) of the surface-treated crosslinked polymer particles (X) and the surface-treated crosslinked polymer particles (Y) with respect to physiological saline (0.9% by weight aqueous sodium chloride solution) is preferably 32 or more, and further, It is preferably from 37 to 82, particularly preferably from 42 to 72. That is, the absorption ratio (g / g) of the surface-treated crosslinked polymer particles (X) and the surface-treated crosslinked polymer particles (Y) to physiological saline is preferably 32 or more, more preferably 37 or more, and particularly preferably 42 or more. It is more preferably 82 or less, particularly preferably 72 or less. Under pressure (20 g / cm ² The crosslinked polymer particles (S) of (a) preferably have an absorption capacity (g / g) of 13 or more, more preferably 15 to 70, and particularly preferably 20 to 60. That is, under a pressurized saline solution (20 g / cm ² The cross-linked polymer particles (S) of (a) have an absorption capacity (g / g) of preferably 13 or more, more preferably 15 or more, particularly preferably 20 or more, further preferably 70 or less, and particularly preferably 60 or less. It is.
[0088]
In the absorbent of the present invention, the content (% by weight) of the crosslinked polymer particles (X) is preferably from 20 to 80 based on the total weight of the crosslinked polymer particles (X) and the crosslinked polymer particles (Y). , More preferably 30 to 70, particularly preferably 40 to 60, and most preferably 45 to 55. That is, the content (% by weight) of the crosslinked polymer particles (X) is preferably 20 or more, more preferably 30 or more, based on the total weight of the crosslinked polymer particles (X) and the crosslinked polymer particles (Y). It is particularly preferably at least 40, most preferably at least 45, more preferably at most 80, even more preferably at most 70, particularly preferably at most 60, most preferably at most 55. The content (% by weight) of the crosslinked polymer particles (Y) is preferably from 20 to 80, more preferably 30 to 80, based on the total weight of the crosslinked polymer particles (X) and the crosslinked polymer particles (Y). ~ 70, particularly preferably 40-60, most preferably 45-55.
[0089]
The absorbent of the present invention only needs to uniformly mix the crosslinked polymer particles (X) and the crosslinked polymer particles (Y), and mixes and uniformly mixes the crosslinked polymer particles (X) and the crosslinked polymer particles (Y). As a mixing device for performing this, a conventionally known device can be used. Examples of such known devices include a double-arm kneader, an internal mixer (Banbury mixer), a self-cleaning mixer, a gear compounder, a screw-type extruder, a screw-type kneader, and a mincing machine. A combination of types can be used.
[0090]
The additive (C) can be added to the absorbent of the present invention as needed. As the additive (C), for example, a preservative, a fungicide, an antibacterial agent, an antioxidant, an ultraviolet absorber, a coloring agent, a fragrance, a deodorant, an inorganic powder, an organic fibrous material, and the like can be used. Preservatives include preservatives such as salicylic acid, sorbic acid, dehydroacetic acid and methylnaphthoquinone, and bactericides such as chloramine B and nitrofurazone. Examples of the fungicide include p-butyl benzoate and the like, and examples of the antibacterial agent include benzalkonium chloride and chlorhexidine gluconate. Examples of the antioxidant include triethylene glycol-bis- [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate] and 1,6-hexanediol-bis [3- (3,5- Di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenylphenylpropionate and 3,5-di-tert-butyl-4-hydroxy Hindered phenolic antioxidants such as benzylphosphonate-diethyl ester; amine-based antioxidants such as n-butylamine, triethylamine and diethylaminomethyl methacrylate; and mixtures of two or more thereof. As 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- ( , 5-Di-tert-butyl-2-hydroxyphenyl) benzotriazole, 2- (3,5-di-tert-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole and 2- (3,5-di Benzotriazole-based ultraviolet absorbers such as -t-amyl-2-hydroxyphenyl) benzotriazole, 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5-[(hexyl) oxy ] -Triazine UV absorbers such as phenol, benzophenone UV absorbers such as 2-hydroxy-4-n-octyloxybenzophenone, and oxalic anilide UV absorbers such as 2-ethoxy-2'-ethyloxalic acid bisanilide And a mixture of two or more of these, etc. Examples of the colorant include carbon black, titanium oxide and titanium oxide. Examples thereof include inorganic pigments such as ferrite, organic pigments such as azo lake type, benzimidazolone type and phthalocyanine type, and dyes such as nigrosine type and aniline type. And the like, and synthetic flavors such as menthol, citral, p-methylacetophenone, and floral, etc. Examples of the deodorant include zeolite, silica, flavonoids, and cyclodextrin. , Calcium carbonate, kaolin, talc, mica, bentonite, clay, sericite, asbestos, glass fiber, carbon fiber, glass powder, glass balloon, shirasu balloon, coal powder, metal powder, ceramic powder, silica, zeolite and slate powder, etc. Shape. May be arbitrary, number average particle diameter determined by light scattering method 0.1μm~1mm is preferred. Examples of the organic fibrous materials include natural fibers (cellulose (cotton, sawdust, straw, etc.) and other grass charcoal, wool, microfibrils and bacterial celluloses), artificial fibers (cellulosics such as rayon and acetate), synthetic fibers (Polyamide, polyester, acrylic, etc.), pulp (mechanical pulp (crushed wood pulp from logs and asplund wood pulp, etc.), chemical pulp (sulfite pulp, soda pulp, sulfate pulp, nitrate pulp, chlorine pulp, etc.), semi-chemical Pulp, recycled pulp (for example, mechanically crushed or crushed paper made by once making pulp, or recycled pulp or the like, which is mechanically crushed or crushed waste paper).
[0091]
When the additive (C) is used, the amount (% by weight) of the additive (C) varies depending on the application, but is 0.01 to 0.01% based on the total weight of the crosslinked polymer particles (X) and the crosslinked polymer particles (Y). 20 is preferable, 0.02 to 10 is more preferable, and 0.03 to 8 is particularly preferable. That is, in this case, the added amount (% by weight) is preferably 0.01 or more, more preferably 0.02, based on the total weight of the crosslinked polymer particles (X) and the crosslinked polymer particles (Y). Above, particularly preferably 0.03 or more, and preferably 20 or less, more preferably 10 or less, particularly preferably 8 or less.
[0092]
When the additive (C) is used, it can be added at any stage, and includes the following (1) to (4).
{Circle around (1)} A method in which the additive (C) is mixed in advance with the crosslinked polymer particles (S), the crosslinked polymer particles (X) and / or the crosslinked polymer particles (Y).
{Circle around (2)} A method in which the additive (C) is mixed with the surface modifier (M) or the surface modifier (N), and then mixed and treated with the crosslinked polymer particles (S).
{Circle around (3)} A method of adding the additive (C) while mixing the crosslinked polymer particles (S) and the surface modifier (M) or the surface modifier (N).
(4) A method in which the crosslinked polymer particles (S) are treated with the surface modifier (M) or the surface modifier (N), and then the additive (C) is added and mixed.
Among these methods, the methods (2), (3) and (4) are preferable, and the methods (3) and (4) are more preferable.
[0093]
The absorbent of the present invention is suitable for absorbent articles or the like in which water absorption and / or water retention is required (especially absorbent articles in which blood absorption and / or blood retention is required), and disposable diapers (child paper diapers and diapers). Suitable for sanitary articles (especially sanitary napkins) such as adult paper diapers), sanitary napkins, incontinence pads, breast milk pads, surgical underpads, and pet sheets. In addition, freshness preserving materials, cold insulating materials, desiccants, drip absorbing materials, anti-condensation agents, water retaining agents for plants and soil, coagulants such as sludge, waterproof materials and packing materials for civil engineering construction, electric wire cables and optical fiber cables It is also useful for various applications such as waterstops and artificial snow. That is, the liquid to be absorbed that can be absorbed by the absorbent of the present invention is not particularly limited, and examples thereof include urine, blood and other body fluids, and drip, seawater, industrial wastewater, and muddy water. Among these, urine, blood and other body fluids are preferred, and blood and other body fluids are more preferred.
[0094]
【Example】
Hereinafter, the present invention will be further described with reference to Examples and Comparative Examples, but the present invention is not limited thereto. In addition, unless otherwise specified, a part shows a weight part and% shows a weight%. The blood absorption capacity and blood absorption rate were measured by the following methods. In addition, the absorption capacity with respect to physiological saline and the pressure under physiological saline (20 g / cm ² The method for measuring the absorption capacity of ()) is the same as described above.
[0095]
<Amount of blood absorbed>
A 1.00 g sample is put in a tea bag (length 20 cm, width 10 cm) made of a 250 mesh nylon net and immersed in 300 ml of horse blood (containing 3.8% citric acid; manufactured by Japan Lamb) for 60 minutes. After absorption, the suspension was drained for 15 minutes and drained, and the increased weight was measured to determine the blood absorption (g / g).
[0096]
<Blood absorption rate>
A 0.5 g sample is evenly spread on a Petri dish having a diameter of 60 mm, and 2.5 g of horse blood is dropped at the center in 2 seconds. Horse blood is absorbed by the sample, and a drop of horse blood is dropped from the surface of the sample. The time until disappearance is measured with the naked eye, and is defined as the first blood absorption rate (second). Ten minutes after the end of the first measurement of the absorption rate, 2.5 g of horse blood was dropped again, and the time until the absorption was completed was measured to obtain the second blood absorption rate (second).
[0097]
Synthesis Example X1
A glass reactor is charged with 95 parts of sodium acrylate, 27 parts of acrylic acid, 0.3 part of N, N'-methylenebisacrylamide and 430 parts of deionized water, and the contents are heated to 5 ° C. while stirring and mixing. Kept. After flowing nitrogen into the contents, 1 part of a 1% aqueous solution of hydrogen peroxide and 1 part of a 0.3% aqueous solution of ascorbic acid were added to initiate polymerization. Ten minutes after the addition of hydrogen peroxide and ascorbic acid, the temperature began to rise due to polymerization, and reached 60 ° C. 40 minutes after the temperature began to rise. Further, polymerization was carried out at 60 ° C. for 12 hours to obtain a water-containing resin. The hydrated resin is dried with hot air at 130 to 150 ° C. for 20 minutes, pulverized using a juicer mixer, and the particles passing through a JIS standard sieve of 30 mesh (590 μm) without passing through a JIS standard sieve of 60 mesh (250 μm) are used. The particle size was adjusted by collecting the particles to obtain 250 to 590 μm crosslinked polymer particles (S1).
[0098]
The water content of the crosslinked polymer particles (S1) measured by an infrared moisture meter (FD-100, manufactured by Kett) was 15%. 100 parts of the crosslinked polymer particles (S1) were placed in a table type kneader (PN-1 type, manufactured by Irie Shokai), and a perfluoroalkylethylene oxide adduct [Dainippon Ink Chemical, Megafac F-142D, surface tension 19 .0 dynes / cm] and stirred at 25 rpm at 50 rpm for 30 minutes to obtain crosslinked polymer particles. While stirring 100 g of the crosslinked polymer particles in a table type kneader at 50 rpm, 1 part of a 10% aqueous solution of ethylene glycol diglycidyl ether is sprayed, and a heat treatment is performed at about 140 ° C. for 30 minutes to crosslink the vicinity of the surface. Further, by performing a heat treatment at about 140 ° C. to adjust the water content to 5%, crosslinked polymer particles (X1) were obtained.
[0099]
Synthesis Example X2
Crosslinking was carried out in the same manner as in Synthesis Example X1, except that the amino-modified silicone [Shin-Etsu Chemical Co., Ltd., trade name: KF880 (surface tension: 24 dynes / cm)] was used in Synthesis Example X1 without adding a perfluoroalkylethylene oxide adduct. Polymer particles (X2) were obtained.
[0100]
Synthesis Example X3
Synthesis Example X1 was the same as Synthesis Example X1 except that the perfluoroalkylethylene oxide adduct was not added, and a modified product of polypropylene maleic anhydride [Sanyo Chemical Industries, Ltd., trade name: Umex 100TS, surface tension 26 dynes / cm] was used. Crosslinked polymer particles (X3) were obtained in the same manner.
[0101]
Synthesis Example X4
145.4 parts of acrylic acid was diluted with 9.4 parts of water, and neutralized by adding 242.3 parts of a 25% aqueous sodium hydroxide solution while cooling to 30 to 20 ° C. To this solution, 0.0727 parts of ethylene glycol diglycidyl ether (manufactured by Nagase Kasei Kogyo Co., Ltd., Denacol EX-810), 0.0146 parts of sodium hypophosphite monohydrate and 0.0727 parts of potassium persulfate are added. And dissolved to obtain an aqueous monomer solution. Next, 624 parts of cyclohexane was placed in a four-necked flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas inlet tube, and polyoxyethylene octylphenyl ether phosphate (Daiichi Kogyo Seiyaku Co., Ltd. (Trade name: Blysurf A210G) 1.56 parts was added and dissolved, nitrogen gas was introduced with stirring at 400 rpm, and the temperature was raised to 70 ° C. Then, while maintaining the temperature at 70 ° C., the adjusted monomer aqueous solution was dropped at 6.6 parts / minute for 6 minutes. After holding for 6 minutes at 75 ° C. for 15 minutes, the remaining monomer aqueous solution was dropped at 6.6 parts / minute over 54 minutes. Then, it aged at 75 degreeC for 30 minutes. Thereafter, water was removed by azeotropy with cyclohexane until the water content of the resin became about 20% (measured by an infrared moisture meter (FD-100, manufactured by Kett)). When the mixture was cooled to 30 ° C. and the stirring was stopped, the resin particles settled. Therefore, the resin particles were separated from cyclohexane by decantation. 80 parts of the resin particles and 140 parts of cyclohexane were put in an eggplant flask, and 0.35% by weight of glycerin polyglycidyl ether (Nagase Chemical Industry Co., Ltd., trade name: Denacol EX-314) and a perfluoroalkylethylene oxide adduct ( Dainippon Ink and Chemicals, trade name: Megafac F-142D, surface tension: 19.0) After adding 3.4 parts of a cyclohexane solution containing 0.025% by weight, the mixture was heated at 60 ° C and held for 30 minutes. Thereafter, the mixture was further heated and kept under reflux of cyclohexane for 30 minutes. Next, the mixture was filtered to obtain resin particles, and dried at 80 ° C. under reduced pressure to obtain crosslinked polymer particles (X4).
[0102]
Synthesis Example X5
Crosslinking was performed in the same manner as in Synthesis Example X4 except that in Example X4, a perfluoroalkylethylene oxide adduct was not added, and an amino-modified silicone [Shin-Etsu Chemical Co., Ltd., trade name: KF880 (surface tension: 24 dynes / cm)] was used. Polymer particles (X5) were obtained.
[0103]
Synthesis Example X6
Synthetic Example X4 was the same as Synthetic Example X4 except that the perfluoroalkylethylene oxide adduct was not used, and a modified product of maleic anhydride [Sanyo Kasei Kogyo Co., Ltd., trade name: Umex 100TS, surface tension 26.0] was used. Thus, crosslinked polymer particles (X6) were obtained.
[0104]
Synthesis Example Y1
The same procedure as in Synthesis Example X1 was carried out except that, in Synthesis Example X1, a perfluoroalkylethylene oxide adduct was not added and polyethylene glycol [Sanyo Kasei Co., Ltd., trade name: PEG200 (surface tension: 55 dynes / cm)] was used. The united particle (Y1) was obtained.
[0105]
Synthesis Example Y2
Synthesis Example X1 was the same as Synthesis Example X1 except that a polycation [Sanyo Chemical Co., Ltd., trade name: Sanfloc CD-269P (surface tension: 72 dynes / cm)] was used in Synthesis Example X1 without adding a perfluoroalkylethylene oxide adduct. Similarly, crosslinked polymer particles (Y2) were obtained.
[0106]
Synthesis Example Y3
In Synthesis Example X4, except that a perfluoroalkylethylene oxide adduct was not added and polyethylene glycol [Sanyo Chemical Co., Ltd., trade name: PEG200 (surface tension: 55 dynes / cm)] was used, the crosslinking weight was the same as in Synthesis Example X4. The united particle (Y3) was obtained.
[0107]
Synthesis Example Y4
Synthetic Example X4 was the same as Synthetic Example X4 except that no perfluoroalkylethylene oxide adduct was added and a polycation [Sanyo Chemical Industry Co., Ltd., trade name: Sanfloc CD-269P (surface tension: 72 dynes / cm)] was used. Similarly, crosslinked polymer particles (Y4) were obtained.
[0108]
<Example 1>
100 parts of the crosslinked polymer particles (X1) and 100 parts of the crosslinked polymer particles (Y1) were mixed and stirred (high-speed stirring turbulizer manufactured by Hosokawa Micron: 2,000 rpm) to obtain Absorbent 1 of the present invention.
[0109]
<Example 2>
100 parts of the crosslinked polymer particles (X1) and 100 parts of the crosslinked polymer particles (Y2) were mixed and stirred (high-speed stirring turbulizer manufactured by Hosokawa Micron: 2,000 rpm) to obtain Absorbent 2 of the present invention.
[0110]
<Example 3>
100 parts of the crosslinked polymer particles (X2) and 100 parts of the crosslinked polymer particles (Y1) were mixed and stirred (a high-speed stirring turbulizer manufactured by Hosokawa Micron: 2,000 rpm) to obtain an absorbent 3 of the present invention.
[0111]
<Example 4>
100 parts of the crosslinked polymer particles (X2) and 100 parts of the crosslinked polymer particles (Y2) were mixed and stirred (high-speed stirring turbulizer manufactured by Hosokawa Micron: 2,000 rpm) to obtain Absorbent 4 of the present invention.
[0112]
<Example 5>
100 parts of the crosslinked polymer particles (X3) and 100 parts of the crosslinked polymer particles (Y1) were mixed and stirred (a high-speed stirring turbulizer manufactured by Hosokawa Micron: 2,000 rpm) to obtain Absorbent 5 of the present invention.
[0113]
<Example 6>
100 parts of the crosslinked polymer particles (X3) and 100 parts of the crosslinked polymer particles (Y2) were mixed and stirred (high-speed stirring turbulizer manufactured by Hosokawa Micron: 2,000 rpm) to obtain absorbent 6 of the present invention.
[0114]
<Example 7>
100 parts of the crosslinked polymer particles (X4) and 100 parts of the crosslinked polymer particles (Y3) were mixed and stirred (a high-speed stirring turbulizer manufactured by Hosokawa Micron: 2,000 rpm) to obtain an absorbent 7 of the present invention.
[0115]
Example 8
100 parts of the crosslinked polymer particles (X4) and 100 parts of the crosslinked polymer particles (Y4) were mixed and stirred (high-speed stirring turbulizer manufactured by Hosokawa Micron: 2,000 rpm) to obtain Absorbent 8 of the present invention.
[0116]
<Example 9>
100 parts of the crosslinked polymer particles (X5) and 100 parts of the crosslinked polymer particles (Y3) were mixed and stirred (a high-speed stirring turbulizer manufactured by Hosokawa Micron: 2,000 rpm) to obtain an absorbent 9 of the present invention.
[0117]
<Example 10>
100 parts of the crosslinked polymer particles (X5) and 100 parts of the crosslinked polymer particles (Y4) were mixed and stirred (high-speed stirring turbulizer manufactured by Hosokawa Micron: 2,000 rpm) to obtain the absorbent 10 of the present invention.
[0118]
<Example 11>
100 parts of the crosslinked polymer particles (X6) and 100 parts of the crosslinked polymer particles (Y3) were mixed and stirred (high-speed stirring turbulizer manufactured by Hosokawa Micron: 2,000 rpm) to obtain absorbent 11 of the present invention.
[0119]
<Example 12>
100 parts of the crosslinked polymer particles (X6) and 100 parts of the crosslinked polymer particles (Y4) were mixed and stirred (high-speed stirring turbulizer manufactured by Hosokawa Micron: 2,000 rpm) to obtain the absorbent 12 of the present invention.
[0120]
<Comparative Examples 1 to 10>
The crosslinked polymer particles (X1) to (X6) and (Y1) to (Y4) obtained in the synthesis example were directly used as the absorbent of the comparative example. Table 1 shows these relationships.
[Table 1]

[0121]
With respect to the absorbents of Examples 1 to 12 and Comparative Examples 1 to 10, the absorbency against physiological saline, the absorbency against physiological saline under pressure, the amount of blood absorbed, and the rate of blood absorption were evaluated. Shown in
[Table 2]

[0122]
As can be seen from Table 2, when the absorbent of the present invention (Examples 1 to 12) and the absorbent of Comparative Examples 1 to 10 are compared, the absorbency against saline solution of the present invention and the absorption under pressure against saline solution are shown. The magnification and the amount of blood absorption are equal to or higher than those of the comparative example, and the blood absorption rate of the present invention is remarkably excellent.
[0123]
【The invention's effect】
The absorbent of the present invention is excellent in the balance between the absorption rate and the absorption amount, which has been a problem for the water-absorbent resin, and both exhibit excellent performance. In particular, the blood absorption rate is remarkably excellent, so that it is optimal as a blood absorbent.

Claims (5)

Surface-treated crosslinked polymer particles (X) comprising a crosslinked polymer particle (S) having (meth) acrylic acid (salt) as a main constituent unit and a surface modifier (M) having a surface tension of 10 to 30 dynes / cm. ) And a surface-treated crosslinked polymer particle (Y) comprising a crosslinked polymer particle (S) and a surface modifier (N) having a surface tension of 40 to 80 dynes / cm. Absorbent. The absorbent according to claim 1, wherein the surface modifier (M) is a surface modifier (M2) containing a hydrocarbon group having a fluorine atom or a surface modifier (M3) containing a siloxane structure. The absorbent according to claim 1, wherein the surface modifier (N) is a polyalkylene glycol. An absorbent article comprising the absorbent according to claim 1. The absorbent article according to claim 4, comprising blood as the liquid to be absorbed.