JP2004068227A - Adhesive for laminated paper and method for producing laminated paper - Google Patents

Abstract

An existing dispersion polymer in polyethylene glycol has coexisting polyethylene glycol which affects paper strength and reduces the effect. In addition, in the case of the dispersion polymer in a salt aqueous solution, the timing of each of the dehydration and drying steps in the laminating process did not match the timing of dissolving the adhesive particles and developing the adhesive force. That is, the ratio of the particles dissolved before the drying step and flowing out by a dehydration press or the like was high. It is an object of the present invention to reduce the amount of outflow, and to make the amount of the paper staying on the paper layer surface of the laminating surface and the rate of permeation into the paper layer appropriate, thereby balancing the interlaminar strength and the inner strength of the paper layer. We will develop an adhesive for laminated paper that will improve the strength of the laminated paper.
A water-soluble polymer comprising one or more ionic or non-ionic fine particles having a particle size of 100 μm or less selected from cationic, amphoteric, anionic and nonionic, and a polyalkyleneimine; And / or the polyalkylenimine-modified product can be achieved by an adhesive for laminated paper comprising a dispersion coexisting in an aqueous salt solution.
[Selection diagram] None

Description

一般式（１）
Ｒ１は水素又はメチル基、Ｒ２、Ｒ３は炭素数１〜３のアルキル基、アルコキシ基あるいはベンジル基、Ｒ４は水素、炭素数１〜３のアルキル基、アルコキシ基あるいはベンジル基であり、同種でも異種でも良い。Ａは酸素またはＮＨ、Ｂは炭素数２〜４のアルキレン基またはアルコキシレン基、Ｘ１は陰イオンをそれぞれ表わす
【化２】

一般式（２）
Ｒ５は水素又はメチル基、Ｒ６、Ｒ７は炭素数１〜３のアルキル基、アルコキシ基あるいはベンジル基、Ｘ２は陰イオンをそれぞれ表わす
【化３】

一般式（３）
Ｒ８は水素、メチル基またはカルボキシメチル基、ＱはＳＯ３、Ｃ６Ｈ４ＳＯ３、
ＣＯＮＨＣ（ＣＨ３）２ＣＨ２ＳＯ３、Ｃ６Ｈ４ＣＯＯあるいはＣＯＯ、Ｒ９は水素またはＣＯＯＹ２、Ｙ１あるいはＹ２は水素または陽イオン
【０００８】
請求項３の発明は、前記分散液が、前記一般式（３）で表わされる単量体の一種以上２〜５０モル％、水溶性非イオン性単量体５０〜９８モル％からなる単量体混合物を攪拌下、ポリアルキレンイミン及び／又はポリアルキレンイミン変性物を共存させ、塩水溶液中において分散重合し製造されたものであることを特徴とする請求項１に記載の分散液からなる抄き合わせ紙用接着剤である。
【０００９】
請求項４の発明は、前記分散液が、前記水溶性非イオン性単量体の一種以上からなる単量体（混合物）を攪拌下、ポリアルキレンイミン及び／又はポリアルキレンイミン変性物を共存させ、塩水溶液中において分散重合し製造されたものであることを特徴とする請求項１に記載の分散液からなる抄き合わせ紙用接着剤である。
【００１０】
請求項５の発明は、前記ポリアルキレンイミン変性物が、下記一般式（４）及び／または（５）で表される構造単位を有することを特徴とする請求項１〜４に記載の分散液からなる抄き合わせ紙用接着剤である。
【化４】

一般式（４）
【化５】

一般式（５）
但し、式（４）、（５）中のｐは０〜２０の整数であり、Ｒ１０〜Ｒ１７は水素、又は炭素数１〜３のアルキル基、ヒドロキシアルキル碁あるいはベンジル基、Ｘ３〜Ｘ６は陰イオンである。
【００１１】
請求項６の発明は、前記ポリアルキレンイミン変性物が、ポリアルキレンイミンあるいはポリアルキレンイミンとポリアミン混合物と下記一般式（６）及び／または（７）で表されるポリカチオン物質との反応物からなることを特徴とする請求項１〜５に記載の分散液からなる抄き合わせ紙用接着剤である。
【化６】

一般式（６）
【化７】

一般式（７）
但し、式（６）、（７）中のＰはエポキシ基あるいはハロヒドリン基、ｐは０〜２０の整数であり、Ｒ１８〜Ｒ２６は水素、炭素数１〜３のアルキル基、ヒドロキシアルキル基あるいはベンジル基、Ｘ７〜Ｘ１０は陰イオンである。
【００１２】
請求項７の発明は、前記ポリアルキレンイミン変性物が、前記一般式（６）で表されるポリカチオン物質によって架橋されていることを特徴とする請求項１〜５に記載の分散液からなる抄き合わせ紙用接着である。
【００１３】
請求項８の発明は、紙層形成後の湿潤紙層を抄き合わせた後プレスし、さらに乾燥する工程を含む２層以上の抄き合わせ紙を製造する際に、抄き合わせ前の湿潤紙層表面に、請求項１〜７に記載の分散液からなる抄き合わせ紙用接着剤を、噴霧することを特徴とする抄き合わせ紙の製造方法である。
【００１４】
【発明の実施の形態】
本発明の特徴は、塩水溶液中において、製紙用薬剤として有用なポリエチレンイミン及び／又はポリエチレンイミン変性物を、単量体と共存させて攪拌下、重合することにより製造した水溶性重合体微粒子からなる分散液を抄き合わせ紙用接着剤に応用することにある。従来の水溶性重合体分散液の製造方法は、前記一般式（１）あるいは（２）で表される単量体をポリエチレングリコールやジメチルジアリルアンモニウム塩化物中で重合を行うと、生成した重合物分散液は、粘性の高い分散液になり、重合物分子量も高くはならなかった。しかし、本発明のポリエチレンイミン及び／又はポリエチレンイミン変性物中において重合すると、これらの問題が解決することができる。
【００１５】
以下、まず製造法を説明する。初めにポリエチレンイミン及び／又はポリエチレンイミン変性物の２０〜５０重量％水溶液を用意し、有機又は無機酸によりアミン当量の５０〜１００％を中和する。この時の水溶液ｐＨは、２〜１２に調整し、この水溶液に単量体を加え、混合する。単量体濃度としては、１０〜４０重量％であり、好ましくは１５〜３０重量％である。ポリエチレンイミン及び／又はポリエチレンイミン変性物の単量体に対する添加量は、５〜２００重量％であるが、好ましくは１０〜１５０重量％、さらに好ましくは１０〜１００重量％である。また、無機塩を全量に対し２重量％〜飽和濃度となるよう溶解する。
【００１６】
その後、窒素雰囲気下にて、重合開始剤、例えば２、２’−アゾビス（アミジノプロパン）二塩化水素化物または２、２’−アゾビス〔２−（５−メチル−２−イミダゾリン−２−イル）プロパン〕二塩化水素化物のような水溶性アゾ系重合開始剤、あるいは過硫酸アンモニウムおよび亜硫酸水素ナトリウム併用のような水溶性レドックス系重合開始剤を添加し、撹拌下ラジカル重合を行う。重合の反応温度は０〜１００℃の範囲で重合開始剤の性質に応じて任意に選ぶ事ができるが、好ましくは１０〜６０℃であり、更に好ましくは２０〜５０℃である。
【００１７】
本発明で使用するポリアルキレンイミンは、ポリエチレンイミンあるいはポリプロピレンイミンなどであるが、実用的にはポリエチレンイミンである。分子量は、５０００以上あれば本発明の分散重合に使用できるが、あまり重合度が高いと分散液の粘性が高くなり好ましくない。従って好ましくは５０００以上、５００，０００以下であり、更に好ましくは５０００以上、２００，０００以下である。また、ポリアルキレンイミン変性物の場合も同様に、変性後の分子量が好ましくは５０，０００以上、１，０００，０００以下であり、更に好ましくは５０，０００以上、５００，０００以下である。
【００１８】
またポリアルキレンイミン変性物も使用することができる。例えばエピクロロヒドリン、エチレングリコールジグリシジルエーテルなどで架橋により変性したポリアルキレンイミンも使用することができるが、一般式（４）あるいは（５）で表される構造単位を有するポリアルキレンイミン変性物を使用することが好ましい。これはポリアルキレンイミンあるいはポリアルキレンイミンとポリアミンとの混合物と、一般式（６）及び／又は（７）で表されるポリカチオン物質との反応とによって合成されるものである。この物質は、アンモニア、脂肪族第一級〜第ニ級アミン（以下第一級アミンなどと記載する）から選択された一種以上のアミン類とエピハロヒドリンを反応させて製造することができる。
【００１９】
変性反応時のモル比については以下の範囲で行う。すなわちポリアルキレンイミン中あるいはポリアルキレンイミンとポリアミンとの混合物中のアミノ基をＣ（モル単位）と、前記一般式（６）及び／または（７）で表されるポリカチオン物質中のハロヒドリン基及び／またはエポキシ基をＤ（モル単位）とすると、Ｃ／Ｄ＝５〜３００（モル％）の範囲で反応する。例えばポリアルキレンイミンの分子量が数万〜数十万と高い場合は、特に上記一般式（６）で表されるポリカチオン物質を高い比率でし込むと、架橋反応が進み過ぎてポリアルキレンイミンが水不溶化してしまう。したがってし込みモル％としては、通常５〜５０モル％、好ましくは５〜３０モル％である。一方ポリアルキレンイミンの分子量が１，０００〜１０，０００など低い場合は、し込みモル％としては、通常５０〜３００モル％、好ましくは７０〜１５０モル％である。
【００２０】
前記ポリカチオン物質は、一般式（６）で表される両末端反応性のある架橋作用のあるものと、一般式（７）で表される片末端反応性のあるグラフト反応作用のあるものとがある。前者の架橋作用のあるものは、エピハロヒドリンに対するアンモニア、第１級アミン、第２級アミンから選択された１種以上のアミン類のモル比が、凡そ０．２５〜０．９の範囲で反応させると一般式（６）で表されるポリカチオン物質の生成比率が高く、後者のグラフト作用のあるものは、エピハロヒドリンに対するアンモニア、第一級アミン、第ニ級アミンから選択された１種以上のアミン類のモル比が、凡そ０．８〜１．２の範囲で反応させると一般式（７）で表されるポリカチオン物質の生成比率が高くなる。
【００２１】
重合は一般的には中性〜酸性で行うのが、単量体も安定であり、反応性も良好であり、重合度や重合率も向上するので、ポリアルキレンイミンあるいはポリアルキレンイミン変性物は、中和して弱アルカリ〜酸性の水溶液とすることが好ましい。ｐＨとしては１２〜２であるが、好ましくは１０〜３であり、更に好ましくは６〜３である。中和する酸は、有機あるいは無機の酸を使用する。有機酸としては、蟻酸、酢酸、アジピン酸、無機酸としては、塩酸、硫酸、スルファミン酸などで中和する。中和度としては、分子中のアミノ基に対して、５０〜１００当量％である。
【００２２】
重合時、ポリアルキレンイミン及び／又はポリアルキレンイミン変性物と併用する塩としては、ハロゲン化アルカリ金属塩や、硫酸塩、燐酸塩などである。具体的には、塩化ナトリウム、塩化カリウム、臭化ナトリウム、塩化アンモニウム、臭化カリウム、臭化アンモニウム、硫酸アンモニウム、硫酸ナトリウム、硫酸マグネシウム、硫酸アルミニウム、燐酸水素アンモニウム、燐酸水素ナトリウム、燐酸水素カリウム等を例示することができ、これらの塩を液中濃度として２重量％〜飽和濃度として用いることが好ましい。
【００２３】
分子量調節のため通常のラジカル重合に用いられるようなイソプロピルアルコールやメルカプタン等の連鎖移動剤を添加することも任意に選択することができる。重合体微細粒子の分散安定化の為、撹拌を行う必要がり、撹拌速度の上限は無く、任意の撹拌条件を選ぶことができる。
【００２４】
次に分散液からなる抄き合わせ紙用接着剤を製造する場合に使用する単量体について説明する。カチオン性重合体の分散液からなる抄き合わせ紙用接着剤を製造する場合には、カチオン性単量体の一種以上を使用し、非イオン性単量体を共重合する。カチオン性単量体の例としては、一般式（１）で表される（メタ）アクリル酸ジメチルアミノエチルやジメチルアミノプロピル（メタ）アクリルアミドなどが上げられる。四級アンモニウム基含重合体の例は、前記三級アミノ含有単量体の塩化メチルや塩化ベンジルによる四級化物である（メタ）アクリロイルオキシエチルトリメチルアンモニウム塩化物、（メタ）アクリロイルオキシ２−ヒドロキシプロピルトリメチルアンモニウム塩化物、（メタ）アクリロイルアミノプロピルトリメチルアンモニウム塩化物、（メタ）アクリロイルオキシエチルジメチルベンジルアンモニウム塩化物、（メタ）アクリロイルオキシ２−ヒドロキシプロピルジメチルベンジルアンモニウム塩化物、（メタ）アクリロイルアミノプロピルジメチルベンジルアンモニウム塩化物などである。また、一般式（２）で表されるジメチルジアリルアンモニウム系単量も使用可能であり、その例としてジメチルジアリルアンモニウム塩化物、ジアリルメチルベンジルアンモニウム塩化物などである。
【００２５】
また、これらカチオン性単量体のうち好ましいものは、一般式（１）及び／又は（２）で表される（メタ）アクリル酸ジメチルアミノエチル、ジメチルアミノプロピル（メタ）アクリルアミド及びメチルジアリルアミンなどの三級アミン型単量体である。
【００２６】
水溶性非イオン性単量体の例としては、（メタ）アクリルアミド、Ｎ，Ｎ−ジメチルアクリルアミド、酢酸ビニル、アクリロニトリル、（メタ）アクリル酸２−ヒドロキシエチル、ジアセトンアクリルアミド、Ｎ−ビニルピロリドン、Ｎ−ビニルホルムアミド、Ｎ−ビニルアセトアミドアクリロイルモルホリン、アクリロイルピペラジンなどがあげられる。最も好ましい水溶性非イオン性単量体は、アクリルアミドである。
【００２７】
両性重合体の分散液からなる抄き合わせ紙用接着剤を製造する場合には、前記カチオン性と水溶性非イオン性単量体に加えて、さらに一般式（３）で表されるアニオン性単量体を共重合する。その例としては、スルフォン基でもカルボキシル基でもさしつかいなく、両方を併用しても良いが、好ましくはカルボキシル基含有単量体である。スルフォン基含有単量体の例は、ビニルスルフォン酸、ビニルベンゼンスルフォン酸あるいは２−アクリルアミド２−メチルプロパンスルフォン酸などである。またカルボキシル基含有単量体の例は、メタクリル酸、アクリル酸、イタコン酸、マレイン酸あるいはｐ−カルボキシスチレンなどである。最も好ましい単量体は、アクリル酸やイタコン酸である。
【００２８】
また、アニオン性重合体の分散液からなる抄き合わせ紙用接着剤を製造する場合には、前記一般式（３）で表されるアニオン性単量体と前記水溶性非イオン性単量体を共重合する。この場合も前記と同様に、スルフォン基でもカルボキシル基でもさしつかいなく、両方を併用しても良いが、好ましくはカルボキシル基含有単量体である。すなわち最も好ましい単量体は、アクリル酸やイタコン酸であり、最も好ましい水溶性非イオン性単量体は、アクリルアミドである。
【００２９】
さらに、非イオン性重合体の分散液からなる抄き合わせ紙用接着剤を製造する場合には、前記水溶性非イオン性単量体のうち、一種以上を（共）重合する。すなわち最も好ましい水溶性非イオン性単量体は、アクリルアミドである。
【００３０】
各イオン性重合体中の単量体組成としては、カチオン性重合体の分散液からなる抄き合わせ紙用接着剤の場合は、カチオン性単量体１〜５０モル％、水溶性非イオン性単量体５０〜９９モル％であり、好ましくはカチオン性単量体３〜３０モル％、水溶性非イオン性単量体７０〜９７モル％である。また、両性重合体の分散液からなる抄き合わせ紙用接着剤の場合は、カチオン性単量体１〜５０モル％、アニオン性単量体１〜５０モル％、水溶性非イオン性単量体０〜９８モル％であり、好ましくはカチオン性単量体３〜４０モル％、アニオン性単量体３〜３０モル％、水溶性非イオン性単量体３０〜９４モル％である。アニオン性重合体の分散液からなる抄き合わせ紙用接着剤の場合は、アニオン性単量体２〜５０モル％、水溶性非イオン性単量体５０〜９８モル％であり、好ましくはアニオン性単量体３〜３０モル％、水溶性非イオン性単量体７０〜９７モル％である。またこれらイオン性重合体の重量平均分子量は、１０万〜１０００万であり、好ましくは１００万〜６００万であり、最も好ましくは２００万〜６００万である。
【００３１】
重合開始は、ラジカル重合開始剤を用いる。そのような開始剤は油溶性あるいは水溶性のどちらでも良く、アゾ系，過酸化物系、レドックス系いずれでも重合することが可能である。油溶性アゾ系開始剤の例としては、２、２’−アゾビスイソブチロニトリル、１、１’−アゾビス（シクロヘキサンカルボニトリル）、２、２’−アゾビス（２−メチルブチロニトリル）、２、２’−アゾビス（２−メチルプロピオネ−ト）、４、４−アゾビス（４−メトキシ−２、４ジメチル）バレロニトリルなどがあげられ、水混溶性溶剤に溶解し添加する。
【００３２】
水溶性アゾ系開始剤の例としては、２、２’−アゾビス（アミジノプロパン）二塩化水素化物、２、２’−アゾビス〔２−（５−メチル−２−イミダゾリン−２−イル）プロパン〕二塩化水素化物、４、４’−アゾビス（４−シアノ吉草酸）などがあげられる。またレドックス系の例としては、ペルオクソ二硫酸アンモニウムと亜硫酸ナトリウム、亜硫酸水素ナトリウム、トリメチルアミン、テトラメチルエチレンジアミンなどとの組み合わせがあげられる。さらに過酸化物の例としては、ペルオクソ二硫酸アンモニウムあるいはカリウム、過酸化水素、ベンゾイルペルオキサイド、ラウロイルペルオキサイド、オクタノイルペルオキサイド、サクシニックペルオキサイド、ｔ−ブチルペルオキシ２−エチルヘキサノエ−トなどをあげることができる。
【００３３】
また、本発明の分散液からなる抄き合わせ紙用接着剤は、ポリアルキレンイミン及び／又はポリアルキレンイミン変性物の他、分子量の比較的低い他のカチオン性水溶性重合体を併用することも好ましい。そのようなカチオン性水溶性重合体としては、前記一般式（１）及び／又は前記一般式（２）で表されるカチオン性単量体一種以上の重合体あるいは共重合体である。あるいは前記カチオン性単量体一種以上と水溶性非イオン性単量体との共重合体も使用できる。これらカチオン性水溶性重合体は、重合時、あるいは重合後添加する。分子量は、１，０００〜３，０００，０００であり、好ましくは１０，０００〜２，０００，０００である。
【００３４】
本発明の分散液からなる抄き合わせ紙用接着剤は、単量体を重合する際、ポリアルキレンイミン及び／又はポリアルキレンイミン変性物を共存させるので、ポリアルキレンイミン及び／又はポリアルキレンイミン変性物の一部に一般式（１）〜（３）で表される単量体がグラフト重合していると推定される。さらにポリアルキレンイミン及び／又はポリアルキレンイミン変性物は、非常に枝分かれした構造をしているため、それだけグラフト重合も起こりやすいと考えられ、分散液の安定化にも大いに寄与すると推定され、重合の分散助剤としては非常に適した材料である。
【００３５】
本発明の分散液からなる抄き合わせ紙用接着剤は、ポリエチレンイミンやポリエチレンイミン変性物が共存しているため古紙や機械パルプに由来するピッチ類あるいはアニオン性物質の表面電荷中和作用を行うことができる。すなわち、前記アニオン性物質やピッチ類によって、噴霧添加した接着剤粒子が製紙原料への吸着阻害を起こすが防止され、その結果脱水プレスによって水とともに流出することが減少し、効率良く添加工程が行われる。そのため今日のように製紙原料中に古紙や機械パルプの配合比が増加した状況に非常に適したものと考えられる。また、ポリエチレンイミンやポリエチレンイミン変性物のようなイオン密度の高い分散剤によって水溶性重合体粒子が覆われているため、従来の塩水溶液中分散重合物のように、乾燥工程に達しない段階で粒子が溶解し、結果脱水プレスによって水に流出しにくくなる。乾燥工程に達して初めて溶解する粒子が増加し、層間強度向上に寄与する粒子の割合が増える。さらに特に、アニオン性あるいは両性水溶性重合体からなる分散液を合成する場合は、ポリイオンコンプレクッスも一部生成していると考えられるので、これら極微細な粒子が紙層中にも浸透して内部強度、あるいは接着面と反対側の紙表面まで達し、表面強度も向上させていると推定される。
【００３６】
本発明で使用する分散液からなる抄き合わせ紙用接着剤の製紙原料への添加量としては、高分子純分として、接着面に対し凡そ０．０５〜数ｇ／ｍ２であり、通常０．０５〜３．０ｇ／ｍ２、最も好ましくは０．１〜１ｇ／ｍ２である。抄紙ｐＨとしては、酸性抄紙〜中性抄紙において他の処理法に比較して優れた効果を発揮する。従って、抄紙ｐＨとして４．０〜９．０の範囲においてメリットがある。対象となる紙製品として、上質板紙、白ボール、黄ボール、中芯原紙やライナ−など抄き合わせを要する板紙である。
【００３７】
【実施例】
以下、実施例および比較例によって本発明をさらに詳しく説明するが、本発明はその要旨を超えない限り、以下の実施例に制約されるものではない。
【００３８】
【実施例１】
攪拌機および温度制御装置を備えた反応器に５０重量％（以下濃度は同様）ポリエチレンイミン水溶液（重量平均分子量；５０，０００）５０ｇを、イオン交換水２１．５ｇに溶解し、７５重量％硫酸２８．５ｇを冷却攪拌下添加し、ｐＨを４．８に調整した。攪拌機、窒素曝気管および温度制御装置を備えた反応器に前記中和操作により得たポリエチレンイミン水溶液６０．０ｇを仕込んだ。別にアクリル酸６０％水溶液、２５．０ｇ、アクリルアミド５０％溶液、９０．０ｇ、塩化ナトリウム１８．４ｇ及びイオン交換水３４．６ｇを加えた。窒素で置換しながら１０重量％の２，２アゾビス（Ｎ，Ｎ−ジメチレンイソブチルアミジン）ジハイドロクロライド水溶液を重合開始剤として対モノマーあたり重量で８００ｐｐｍ添加し、撹拌下３６℃で１８時間重合した。その結果、粒径１０〜１００μｍの微粒子の重合体分散液が得られた（試料−１）。生成したポリマ―分散液をＢ型粘度計により測定した分散液の粘度、また静的光散乱法による分子量測定器（大塚電子製ＤＬＳ−７０００）によって重量平均分子量を測定した。
【００３９】
【実施例２〜６】
上記操作と同様に表ー１記載の組成のモノマーを表１記載の単量体濃度になるように仕込み、重合操作を行い、水溶性重合体分散液を得た（試料−２〜試料−６）。組成を表１、結果を表２に示す。
【００４０】
【実施例７】
温度計、攪拌機、滴下漏斗を備えた４つ口のセパラブルフラスコに、エピクロロヒドリン１４６．６ｇとイオン交換水２９．６ｇを仕込み、ジメチルアミンの５０重量％水溶液１２３．８ｇを４０〜４５℃で２時間かけて滴下し、滴下終了後４５℃で１時間反応後、イオン交換水２９．６ｇを加えた。
【００４１】
次ぎに温度計、攪拌機を備えたセパラブルフラスコに、ポリエチレンイミン（重量平均分子量；１０，０００）、１００％品を２３．３ｇとイオン交換水を６０．０ｇ加えて撹拌後、合成例１のポリカチオン生成物を２６．９ｇ加え、２８℃で４５分間反応させ、反応物の粘度上昇が認められた時点で、７５％硫酸４．５ｇを加えて反応を停止させた。重量平均分子量を測定すると５０，０００であった。
【００４２】
次に攪拌機および温度制御装置を備えた反応器に、上記の操作によって調製したポリエチレンイミン変性物６０ｇを採取し、硫酸で溶液ｐＨを５．５に中和した。その後、実施例１〜６と同様な操作により微粒子の重合体分散液、試料−７を得た。組成を表１、結果を表２に示す。
【００４３】
【比較例１〜４】
重合時使用する分散媒を構成する水溶性高分子として、それぞれ（２；ジメチルジアリルアンモニウムクロリド重合物、分子量１００，０００（比較例１〜３）、（２；ポリエチレングリコール＃５，０００、（比較例４）を使用する場合についておこなった。組成を表１、結果を表２に示す。
【００４４】
【比較例５】
攪拌機、還流冷却管、温度計および窒素導入管を備えた４つ口５００ｍｌセパラブルフラスコに脱イオン水：９３．７ｇ、硫酸アンモニウム３４．０ｇ、塩化ナトリウム６．０ｇ、６０％アクリル酸：３１．３ｇ、５０％アクリルアミド：１４３．８ｇをそれぞれ仕込んだ。また２０重量％のジアリルジメチルアンモニウムクロリド重合物（分子量；３０万）２２．５ｇ（対単量体６．０重量％）を添加した。その後、攪拌しながら窒素導入管より窒素を導入し溶存酸素の除去を行う。この間恒温水槽により３０℃に内部温度を調整する。窒素導入３０分後、２重量％のペルオキソニ硫酸アンモニウム及び亜硫酸水素アンモニウムの１重量％水溶液をそれぞれこの順で２．６ｇ（対単量体０．０７重量％）添加し重合を開始させた。重合開始後８時間たったところで前記開始剤をそれぞれ同量追加し、さらに６時間後にそれぞれ１．３ｇ追加し１５時間で反応を終了した。この試料のアクリル酸とアクリルアミドのモル比は２５：７５であり、粘度は５５０ｍＰａ・ｓであった。なお、顕微鏡観察の結果、５〜２０μｍの粒子であることが判明した。また、重量平均分子量を測定すると、４００万であった。これを比較−５とする。
【００４５】
【表１】

ＡＡＭ：アクリルアミド、ＤＭＭ：メタクリル酸Ｎ，Ｎ−ジメチルアミノエチルＤＭＡ：アクリル酸Ｎ，Ｎ−ジメチルアミノエチル、ＡＡＣ：アクリル酸、ＩＡ：イタコン酸、（１共存高分子；ポリエチレンイミン、（２共存高分子；ポリエチレンイミン変性物、（３共存高分子；ジメチルジアリルアンモニウムクロリド重合物、（４共存高分子；ポリエチレングリコール＃５，０００、共存高分子添加量；対単量体重量％、共存塩濃度；分散液中重量％濃度、共存塩種類；（ａ）塩化ナトリウム、（ｂ）硫酸ナトリウム、（ｃ）硫酸アンモニウム、（ｄ）塩化カリウム
【００４６】
【表２】

分散液粘度；ｍＰａ・ｓ、分子量単位；万
【００４７】
【実施例８〜１４】
ダンボ−ルをパルパ−で離解した後、ナイヤガラ式ビ−タ−にて叩解し、カナデイアンスタンダ−ドフリ−ネス（Ｃ．Ｆ．Ｓ．）４００ｍＬに調整したダンボ−ル古紙に、液体バンド２％添加した後，パルプスラリ−のｐＨを５．０％炭酸ナトリウム水溶液でｐＨ５．８に調整し、市販のアニオン性ポリアクリルアミド系紙力増強剤を対パルプ０．２％添加して攪拌し均一に混合した。得られたダンボ−ル古紙スラリ−を０．５％に希釈し、抄紙ｐＨを測定した後，タッピスタンダ−ドシ−トマシン（１／１６ｍ２）に１Ｌ入れ乾燥坪量８０ｇ／ｍ２の紙を抄紙した。ワイヤ−上のウェットシ−トに濾紙、ク−チプレ−トを乗せク−チロ−ルを３回かけ湿紙を濾紙に転写した。これをＡ層とした。次いで同様に乾燥坪量８０ｇ／ｍ２の紙を抄紙し、ワイヤ−ごと湿紙を直示天秤に乗せ、実施例１〜７で合成した試料−１〜試料−７を表３に記載した所定の希釈濃度に希釈して作った分散液を圧力２．５気圧で１０．０ｇノズルよりスプレ−塗布した。これをＢ層とした。
【００４８】
Ａ層を濾紙がついたままＢ層に合わせ、その後濾紙を剥がした。これをワイヤ−ごとシ−トマシンに戻し、シ−トマシンに水を張りワイヤ−の下まで満たした水を排水することにより減圧脱水し、新たに濾紙を乗せ、ク−チロ−ルを３回かけ濾紙に転写させた。転写した湿紙を２枚の濾紙に挟み、３Ｋｇ／ｍ２の圧力で５分間プレス後、ロ−タリ−ドライヤ−で乾燥させて抄き合わせ紙を得た。得られた抄き合わせ紙を調湿後、Ｊ−ＴＡＰＰＩ紙パルプ試験法ＮＯ．１９−７７に従って、Ｔ字剥離強さ（ｇｆ／５ｃｍ）及び内部強度を測定した。測定結果とともに希釈濃度、塗布量を合わせて表３に示す。
【００４９】
【比較例５〜１０】
比較として表２の比較−１〜比較−５、及び抄き合わせ紙抄造現場で使用されている馬鈴薯澱粉（比較−６）を用いて試験を行った。結果を表３に示す。
【００５０】
【表３】

希釈濃度：重量％、塗布量：ｇ／ｍ２、Ｔ字剥離強さ：ｇｆ／５ｃｍ、
内部強度：Ｋｇ
【００５１】
【実施例１５〜２１】
ＬＢＫＰを主体とした上質紙製造用の製紙原料ｐＨ６．２３、全ｓｓ分２．３７％、灰分０．４１％を用いて抄き合わせ試験を行った。パルプ濃度０．９重量％に水道水を用いて希釈、ＴＡＰＰＩスタンダードシートマシン（１／５０）により坪量７０ｇ／ｍ２の紙を抄紙した。添加薬品として、中性ロジンサイズ、０．２％（対製紙乾燥分、以下同様）、硫酸バンド１．０％、表２の試料−１〜試料−７をそれぞれ０．２％、歩留向上剤としてカチオン性ポリアクリルアミド（分子量；７５０万、カチオン等量値；２．８０ｍｅｑ／ｇ）を対製紙原料０．０１５％、それぞれこの順で１５秒間隔により添加した。以下、実施例８〜１４と同様な操作により試験した。結果を表４に示す。
【００５２】
【比較例１１〜１５】
比較として表２の比較−２〜比較−５及び前記馬鈴薯澱粉（比較−６）を用いて同様な操作により試験を行った。結果を表４に示す。
【００５３】
【表４】

希釈濃度：重量％、塗布量：ｇ／ｍ２、Ｔ字剥離強さ：ｇｆ／５ｃｍ、
内部強度：Ｋｇ
【００５４】
【実施例２２〜２８】
新聞古紙、ｐＨ６．０２、全ｓｓ分２．６％、灰分０．１５％、を用いて抄き合わせ試験を行った。パルプ濃度０．９重量％に水道水を用いて希釈、ＴＡＰＰＩスタンダードシートマシン（１／５０）により坪量７０ｇ／ｍ２の紙を抄紙した。添加薬品として、エマルジョン型ロジンサイズ０．１％、硫酸バンド２．５％、表２の試料−１〜試料−７をそれぞれ０．２％、歩留向上剤としてカチオン性ポリアクリルアミド（分子量；７５０万、カチオン等量値；２．８０ｍｅｑ／ｇ）を対製紙原料０．０１５％、それぞれこの順で１５秒間隔により添加した。以下、実施例８〜１４と同様な操作により試験した。結果を表５に示す。
【００５５】
【比較例１６〜１９】
比較として表２比較−３〜比較−５及び前記馬鈴薯澱粉（比較−６）を用いて同様な操作により試験を行った。結果を表５に示す。
【００５６】
【表５】

希釈濃度：重量％、塗布量：ｇ／ｍ２、Ｔ字剥離強さ：ｇｆ／５ｃｍ、
内部強度：Ｋｇ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an adhesive for laminated paper and a method for producing a laminated paper, and in particular, has one or more ionicity selected from cationic, amphoteric, anionic and nonionic, or The present invention relates to an adhesive for a laminated paper comprising a dispersion in which a water-soluble polymer composed of fine particles having a particle size of 100 μm or less without ionicity and a polyalkylenimine and / or a modified polyalkylenimine are coexisting in an aqueous salt solution. The present invention also relates to a method for producing a laminated paper using the adhesive.
[0002]
[Prior art]
In the case of producing laminated paper, conventionally, starch or modified starch dispersion before gelatinization is sprayed on wet paper before lamination, and then lamination, dehydration and drying are performed to obtain laminated paper. Was. However, the use of starch as an adhesive has several problems. For example, excess dispersion of starch may spoil during storage. In addition, it is not preferable to keep starch or a biodegradable polymer in a relatively large amount on the paper surface or in the paper layer for storage of paper or processed paper products such as generation of mold.
[0003]
Therefore, development of an adhesive for lamination using a synthetic water-soluble polymer has been attempted. There are two types, a polymer ion complex (JP-A-11-36195 or JP-A-7-157999) and a water-soluble polymer fine particle dispersion (JP-A-11-231557). Among them, in the polymer ion complex type, the particles are too small and a large part of the added adhesive penetrates into the laminated paper layer and does not stay on the laminated surface, and as a result, the interlayer strength is not improved. Also, when passing through a dehydrating press, it is easily dissolved and flows out together with water. On the other hand, the dispersion type has a disadvantage that the particles are too large and do not penetrate into the paper layer, and as a result, the internal strength of the paper layer is not improved or the surface strength is not improved. Further, the dissolution of the dispersed particles occurs during drying, and control to an ideal state in which the adhesive force is developed has not yet been sufficiently realized.
[0004]
Methods for producing a water-soluble polymer dispersion in an aqueous salt solution are disclosed in JP-A-61-123610, JP-A-5-32722, and the like. The dispersant used in this case is a homopolymer or a copolymer of dimethylaminoethyl (meth) acrylates, a copolymer with acrylamide, or the like. A method for producing a dispersion of water-soluble polymer fine particles using a polymer aqueous solution such as polyethylene glycol as a dispersion medium is also disclosed in JP-B-62-5170. The adhesive for laminating is a kind of paper strength enhancer, and when polyethylene glycol is used as a dispersion medium, it greatly affects the adhesive strength. Also, in the conventional dispersion-type laminating adhesive, the timing of the lamination, dehydration, and drying steps in papermaking did not match the timing of dissolving the adhesive particles and developing the adhesive force. That is, since the particles are water-soluble polymers even in the dispersion type, the particles did not come into a state of being dissolved for the first time in the ideal drying step.
[0005]
[Problems to be solved by the invention]
Therefore, an object of the present invention is to reduce the rate of dissolution of particles before spraying and drying by a dehydrating press at the time of laminating during the laminating, and the amount of particles remaining on the laminating surface of the laminating surface and the paper layer. We develop an adhesive for laminated paper that improves the strength of the laminated paper by balancing the interlayer strength and the strength within the paper layer as a result of making the ratio of permeation into the material appropriate.
[0006]
[Means for Solving the Problems]
The present inventors have studied various methods for solving the above problems, and as a result, have reached the following invention. That is, the invention of claim 1 is characterized in that a water-soluble polymer consisting of fine particles having a particle diameter of 100 μm or less having one or more ionic properties or non-ionic properties selected from cationic, amphoteric, anionic and nonionic The present invention relates to an adhesive for laminated paper comprising a dispersion in which an alkyleneimine and / or a modified polyalkyleneimine coexists in an aqueous salt solution.
[0007]
According to a second aspect of the present invention, the dispersion comprises 1 to 50 mol% of a monomer represented by the following general formula (1) and / or (2), and one kind of a monomer represented by the following general formula (3). A polyalkylenimine and / or a modified polyalkylenimine is coexistent with stirring a monomer mixture consisting of 0 to 50 mol% and 50 to 99 mol% of a water-soluble nonionic monomer, and dispersed in an aqueous salt solution. An adhesive for laminated paper comprising the dispersion according to claim 1, which is produced by polymerization.
Embedded image

General formula (1)
R1 is hydrogen or a methyl group, R2 and R3 are alkyl groups, alkoxy groups or benzyl groups having 1 to 3 carbon atoms, and R4 is hydrogen, alkyl groups, alkoxy groups or benzyl groups having 1 to 3 carbon atoms. But it's fine. A represents oxygen or NH, B represents an alkylene group or alkoxylen group having 2 to 4 carbon atoms, and X1 represents an anion.

General formula (2)
R5 represents hydrogen or a methyl group, R6 and R7 represent an alkyl group having 1 to 3 carbon atoms, an alkoxy group or a benzyl group, and X2 represents an anion.

General formula (3)
R8 is hydrogen, a methyl group or a carboxymethyl group, Q is SO3, C6H4SO3,
CONHC (CH3) 2CH2SO3, C6H4COO or COO, R9 is hydrogen or COOY2, Y1 or Y2 is hydrogen or cation.
The invention according to claim 3 is that the dispersion comprises a monomer comprising at least one of the monomers represented by the general formula (3) and 2 to 50 mol% and a water-soluble nonionic monomer 50 to 98 mol%. 2. A dispersion comprising the dispersion according to claim 1, wherein the mixture is produced by dispersion polymerization in a salt aqueous solution in the presence of a polyalkylenimine and / or a modified polyalkylenimine while stirring the mixture. Adhesive for bonded paper.
[0009]
The invention according to claim 4 is that the dispersion liquid is made to coexist with a polyalkylenimine and / or a polyalkylenimine modified product while stirring a monomer (mixture) composed of one or more of the water-soluble nonionic monomers. 2. An adhesive for laminated paper comprising the dispersion according to claim 1, which is produced by dispersion polymerization in a salt aqueous solution.
[0010]
The invention according to claim 5 is characterized in that the modified polyalkyleneimine has a structural unit represented by the following general formula (4) and / or (5). And an adhesive for laminated paper.
Embedded image

General formula (4)
Embedded image

General formula (5)
Here, p in the formulas (4) and (5) is an integer of 0 to 20, R10 to R17 are hydrogen, an alkyl group having 1 to 3 carbon atoms, a hydroxyalkyl or benzyl group, and X3 to X6 are negative. It is an ion.
[0011]
The invention according to claim 6 is that the modified polyalkyleneimine is obtained by reacting a polyalkyleneimine or a polyalkyleneimine and a polyamine mixture with a polycationic substance represented by the following general formulas (6) and / or (7). An adhesive for laminated paper, comprising the dispersion according to any one of claims 1 to 5.
Embedded image

General formula (6)
Embedded image

General formula (7)
Wherein P in the formulas (6) and (7) is an epoxy group or a halohydrin group, p is an integer of 0 to 20, and R18 to R26 are hydrogen, an alkyl group having 1 to 3 carbon atoms, a hydroxyalkyl group or benzyl. The groups X7 to X10 are anions.
[0012]
The invention according to claim 7 comprises the dispersion according to any one of claims 1 to 5, wherein the modified polyalkylenimine is crosslinked by a polycationic substance represented by the general formula (6). Adhesive for laminated paper.
[0013]
The invention according to claim 8 is a method for producing two or more layers of laminated paper including a step of pressing after mixing the wet paper layer after forming the paper layer and further drying the wet paper layer. A method for producing a laminated paper, comprising spraying an adhesive for a laminated paper comprising the dispersion liquid according to claim 1 onto a surface of a paper layer.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
A feature of the present invention is that, in a salt aqueous solution, polyethyleneimine and / or a modified polyethyleneimine useful as a papermaking agent are mixed with a monomer and polymerized under stirring with water-soluble polymer fine particles. To apply the resulting dispersion to an adhesive for laminated paper. A conventional method for producing a water-soluble polymer dispersion is to polymerize a monomer represented by the general formula (1) or (2) in polyethylene glycol or dimethyldiallylammonium chloride. The dispersion became a highly viscous dispersion, and the molecular weight of the polymer did not increase. However, these problems can be solved by polymerization in the polyethyleneimine and / or modified polyethyleneimine of the present invention.
[0015]
Hereinafter, the manufacturing method will be described first. First, a 20 to 50% by weight aqueous solution of polyethyleneimine and / or a modified polyethyleneimine is prepared, and an organic or inorganic acid is used to neutralize 50 to 100% of the amine equivalent. At this time, the pH of the aqueous solution is adjusted to 2 to 12, and the monomer is added to the aqueous solution and mixed. The monomer concentration is 10 to 40% by weight, preferably 15 to 30% by weight. The addition amount of polyethyleneimine and / or modified polyethyleneimine to the monomer is 5 to 200% by weight, preferably 10 to 150% by weight, and more preferably 10 to 100% by weight. Further, the inorganic salt is dissolved so as to have a concentration of 2% by weight to a saturated concentration with respect to the total amount.
[0016]
Thereafter, under a nitrogen atmosphere, a polymerization initiator such as 2,2′-azobis (amidinopropane) dihydrochloride or 2,2′-azobis [2- (5-methyl-2-imidazolin-2-yl) Propane] A water-soluble azo-based polymerization initiator such as dihydrochloride or a water-soluble redox-based polymerization initiator such as a combination of ammonium persulfate and sodium hydrogen sulfite is added, and radical polymerization is carried out with stirring. The reaction temperature of the polymerization can be arbitrarily selected in the range of 0 to 100 ° C. depending on the nature of the polymerization initiator, but is preferably 10 to 60 ° C., and more preferably 20 to 50 ° C.
[0017]
The polyalkyleneimine used in the present invention is polyethyleneimine or polypropyleneimine, but is practically polyethyleneimine. If the molecular weight is 5,000 or more, it can be used in the dispersion polymerization of the present invention. However, if the degree of polymerization is too high, the viscosity of the dispersion becomes undesirably high. Therefore, it is preferably from 5,000 to 500,000, and more preferably from 5,000 to 200,000. Similarly, in the case of the modified polyalkyleneimine, the molecular weight after modification is preferably 50,000 or more and 1,000,000 or less, more preferably 50,000 or more and 500,000 or less.
[0018]
Further, a polyalkyleneimine modified product can also be used. For example, polyalkylenimines modified by crosslinking with epichlorohydrin, ethylene glycol diglycidyl ether or the like can be used, but modified polyalkylenimines having a structural unit represented by the general formula (4) or (5) It is preferred to use It is synthesized by reacting a polyalkyleneimine or a mixture of a polyalkylenimine and a polyamine with a polycationic substance represented by the general formula (6) and / or (7). This substance can be produced by reacting epihalohydrin with one or more amines selected from ammonia and aliphatic primary to secondary amines (hereinafter referred to as primary amines and the like).
[0019]
The molar ratio during the denaturation reaction is in the following range. That is, the amino group in the polyalkyleneimine or in the mixture of the polyalkylenimine and the polyamine is represented by C (molar unit) and the halohydrin group in the polycationic substance represented by the general formula (6) and / or (7). When the epoxy group is represented by D (mol unit), the reaction is performed in the range of C / D = 5 to 300 (mol%). For example, when the molecular weight of the polyalkyleneimine is as high as tens of thousands to hundreds of thousands, especially when the polycationic substance represented by the general formula (6) is incorporated at a high ratio, the crosslinking reaction proceeds excessively, and Will be insoluble in water. Therefore, the mol% is usually 5 to 50 mol%, preferably 5 to 30 mol%. On the other hand, when the molecular weight of the polyalkylenimine is low, such as 1,000 to 10,000, the mole% is usually 50 to 300 mole%, preferably 70 to 150 mole%.
[0020]
The polycationic substance has a two-terminal reactive cross-linking action represented by the general formula (6) and a one-terminal reactive graft reaction action represented by the general formula (7). There is. The former compound having a cross-linking action is reacted at a molar ratio of one or more amines selected from ammonia, primary amine and secondary amine to epihalohydrin in the range of about 0.25 to 0.9. And the production ratio of the polycationic substance represented by the general formula (6) is high, and the latter having a grafting action is at least one amine selected from ammonia, primary amine, and secondary amine with respect to epihalohydrin. When the reaction is carried out at a molar ratio of about 0.8 to 1.2, the production ratio of the polycationic substance represented by the general formula (7) increases.
[0021]
The polymerization is generally carried out under neutral to acidic conditions, the monomer is stable, the reactivity is good, and the degree of polymerization and the degree of polymerization are improved.Therefore, the polyalkyleneimine or the modified polyalkyleneimine is It is preferable to neutralize to a weakly alkaline to acidic aqueous solution. The pH is 12 to 2, preferably 10 to 3, and more preferably 6 to 3. As the acid to be neutralized, an organic or inorganic acid is used. The organic acid is neutralized with formic acid, acetic acid, adipic acid, and the inorganic acid is neutralized with hydrochloric acid, sulfuric acid, sulfamic acid or the like. The degree of neutralization is 50 to 100 equivalent% with respect to the amino group in the molecule.
[0022]
Salts used in combination with the polyalkylenimine and / or the modified polyalkylenimine during polymerization include alkali metal halides, sulfates and phosphates. Specifically, sodium chloride, potassium chloride, sodium bromide, ammonium chloride, potassium bromide, ammonium bromide, ammonium sulfate, sodium sulfate, magnesium sulfate, aluminum sulfate, ammonium hydrogen phosphate, sodium hydrogen phosphate, potassium hydrogen phosphate, etc. It is preferable to use these salts in a concentration of 2% by weight to a saturation concentration in the liquid.
[0023]
The addition of a chain transfer agent such as isopropyl alcohol or mercaptan, which is used in ordinary radical polymerization, for controlling the molecular weight can be arbitrarily selected. In order to stabilize the dispersion of the polymer fine particles, it is necessary to perform stirring, and there is no upper limit of the stirring speed, and any stirring conditions can be selected.
[0024]
Next, the monomers used in producing the adhesive for laminated paper comprising the dispersion will be described. When producing an adhesive for laminated paper comprising a dispersion of a cationic polymer, one or more cationic monomers are used and a nonionic monomer is copolymerized. Examples of the cationic monomer include dimethylaminoethyl (meth) acrylate and dimethylaminopropyl (meth) acrylamide represented by the general formula (1). Examples of the quaternary ammonium group-containing polymer include (meth) acryloyloxyethyltrimethylammonium chloride and (meth) acryloyloxy 2-hydroxy which are quaternized products of the tertiary amino-containing monomer with methyl chloride or benzyl chloride. Propyltrimethylammonium chloride, (meth) acryloylaminopropyltrimethylammonium chloride, (meth) acryloyloxyethyldimethylbenzylammonium chloride, (meth) acryloyloxy 2-hydroxypropyldimethylbenzylammonium chloride, (meth) acryloylaminopropyl And dimethylbenzylammonium chloride. Also, a dimethyldiallylammonium-based monomer represented by the general formula (2) can be used, and examples thereof include dimethyldiallylammonium chloride and diallylmethylbenzylammonium chloride.
[0025]
Preferred among these cationic monomers are dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylamide, and methyldiallylamine represented by formulas (1) and / or (2). It is a tertiary amine type monomer.
[0026]
Examples of the water-soluble nonionic monomer include (meth) acrylamide, N, N-dimethylacrylamide, vinyl acetate, acrylonitrile, 2-hydroxyethyl (meth) acrylate, diacetone acrylamide, N-vinylpyrrolidone, and N-vinylpyrrolidone. -Vinylformamide, N-vinylacetamidoacryloylmorpholine, acryloylpiperazine and the like. The most preferred water-soluble nonionic monomer is acrylamide.
[0027]
When producing an adhesive for a laminated paper comprising a dispersion of an amphoteric polymer, in addition to the cationic and water-soluble nonionic monomers, an anionic compound represented by the general formula (3) is further added. The monomers are copolymerized. Examples thereof include a sulfone group and a carboxyl group, and both may be used in combination, but a carboxyl group-containing monomer is preferred. Examples of the sulfone group-containing monomer include vinylsulfonic acid, vinylbenzenesulfonic acid, and 2-acrylamido-2-methylpropanesulfonic acid. Examples of the carboxyl group-containing monomer include methacrylic acid, acrylic acid, itaconic acid, maleic acid and p-carboxystyrene. Most preferred monomers are acrylic acid and itaconic acid.
[0028]
When producing an adhesive for a laminated paper comprising a dispersion of an anionic polymer, the anionic monomer represented by the general formula (3) and the water-soluble nonionic monomer are used. Is copolymerized. In this case, as in the above case, either a sulfone group or a carboxyl group may be used. Both may be used in combination, but a carboxyl group-containing monomer is preferable. That is, the most preferred monomers are acrylic acid and itaconic acid, and the most preferred water-soluble nonionic monomer is acrylamide.
[0029]
Further, in the case of producing an adhesive for a laminated paper comprising a dispersion of a nonionic polymer, one or more of the water-soluble nonionic monomers are (co) polymerized. That is, the most preferred water-soluble nonionic monomer is acrylamide.
[0030]
As the monomer composition in each ionic polymer, in the case of an adhesive for a laminated paper comprising a dispersion of a cationic polymer, 1 to 50 mol% of a cationic monomer and a water-soluble nonionic The amount of the monomer is 50 to 99 mol%, preferably 3 to 30 mol% of a cationic monomer and 70 to 97 mol% of a water-soluble nonionic monomer. In addition, in the case of an adhesive for laminated paper comprising a dispersion of an amphoteric polymer, 1 to 50 mol% of a cationic monomer, 1 to 50 mol% of an anionic monomer, and a water-soluble nonionic monomer The amount of the monomer is 0 to 98 mol%, preferably 3 to 40 mol% of a cationic monomer, 3 to 30 mol% of an anionic monomer, and 30 to 94 mol% of a water-soluble nonionic monomer. In the case of an adhesive for a laminated paper comprising a dispersion of an anionic polymer, the content of the anionic monomer is 2 to 50 mol% and the amount of the water-soluble nonionic monomer is 50 to 98 mol%, preferably an anionic monomer. 3 to 30 mol% of a water-soluble monomer and 70 to 97 mol% of a water-soluble nonionic monomer. The weight average molecular weight of these ionic polymers is 100,000 to 10,000,000, preferably 1,000,000 to 6,000,000, and most preferably 2,000,000 to 6,000,000.
[0031]
For the initiation of polymerization, a radical polymerization initiator is used. Such an initiator may be either oil-soluble or water-soluble, and can be polymerized by any of azo, peroxide and redox systems. Examples of the oil-soluble azo initiator include 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexanecarbonitrile), 2,2′-azobis (2-methylbutyronitrile), Examples thereof include 2,2'-azobis (2-methylpropionate), 4,4-azobis (4-methoxy-2,4dimethyl) valeronitrile, and the like, which is dissolved in a water-miscible solvent and added.
[0032]
Examples of the water-soluble azo initiator include 2,2′-azobis (amidinopropane) dichloride and 2,2′-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] Hydrogen chloride, 4,4′-azobis (4-cyanovaleric acid) and the like. Examples of the redox system include a combination of ammonium peroxodisulfate with sodium sulfite, sodium hydrogen sulfite, trimethylamine, tetramethylethylenediamine, and the like. Examples of peroxides include ammonium or potassium peroxodisulfate, hydrogen peroxide, benzoyl peroxide, lauroyl peroxide, octanoyl peroxide, succinic peroxide, t-butylperoxy 2-ethylhexanoate and the like. I can give it.
[0033]
Further, the adhesive for laminated paper comprising the dispersion of the present invention may be used in combination with a polyalkyleneimine and / or a modified polyalkyleneimine, as well as another cationic water-soluble polymer having a relatively low molecular weight. preferable. Such a cationic water-soluble polymer is a polymer or copolymer of one or more cationic monomers represented by the general formula (1) and / or the general formula (2). Alternatively, a copolymer of one or more cationic monomers and a water-soluble nonionic monomer can be used. These cationic water-soluble polymers are added during or after the polymerization. The molecular weight is between 1,000 and 3,000,000, preferably between 10,000 and 2,000,000.
[0034]
Since the adhesive for laminated paper comprising the dispersion of the present invention coexists with a polyalkylenimine and / or a modified polyalkylenimine when polymerizing the monomer, the polyalkylenimine and / or the polyalkylenimine-modified is used. It is estimated that the monomers represented by the general formulas (1) to (3) are graft-polymerized on a part of the product. Furthermore, since the polyalkyleneimine and / or the modified polyalkyleneimine has a very branched structure, it is considered that graft polymerization is likely to occur, and it is presumed that the polyalkyleneimine also greatly contributes to stabilization of the dispersion. It is a very suitable material as a dispersing aid.
[0035]
The adhesive for laminated paper comprising the dispersion of the present invention performs a surface charge neutralizing action on pitches or anionic substances derived from waste paper or mechanical pulp because polyethyleneimine and a modified polyethyleneimine coexist. be able to. That is, the anionic substances and pitches prevent the adhesive particles spray-added from causing adsorption inhibition to the papermaking raw material. As a result, the adhesive particles are prevented from flowing out together with water by the dewatering press, and the addition step can be performed efficiently. Be done. Therefore, it is considered to be very suitable for a situation where the mixing ratio of waste paper and mechanical pulp in the papermaking raw material has increased as in today. In addition, since the water-soluble polymer particles are covered with a dispersant having a high ion density such as polyethyleneimine or a modified polyethyleneimine, at a stage where the drying process is not reached as in a conventional dispersion polymer in a salt solution. The particles dissolve and consequently are less likely to flow into the water by the dewatering press. Only after reaching the drying step, the number of dissolved particles increases, and the proportion of particles that contribute to the improvement in interlayer strength increases. In particular, when synthesizing a dispersion composed of an anionic or amphoteric water-soluble polymer, it is considered that a part of the polyion complex is also generated. It is estimated that the internal strength or the paper surface opposite to the adhesive surface is reached, and the surface strength is also improved.
[0036]
The amount of the adhesive for laminating paper comprising the dispersion used in the present invention to the papermaking raw material is about 0.05 to several g / m2 with respect to the bonding surface, as a pure polymer, and is usually 0%. It is from 0.05 to 3.0 g / m2, most preferably from 0.1 to 1 g / m2. The papermaking pH exhibits excellent effects in acidic papermaking to neutral papermaking as compared with other treatment methods. Therefore, there is an advantage in the papermaking pH in the range of 4.0 to 9.0. Paper products to be processed include high quality paperboard, white balls, yellow balls, core base paper and liners, etc., which require lamination.
[0037]
【Example】
Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the following Examples as long as the gist of the present invention is not exceeded.
[0038]
Embodiment 1
In a reactor equipped with a stirrer and a temperature controller, 50 g of a 50% by weight (the same applies to the following concentration) polyethyleneimine aqueous solution (weight average molecular weight: 50,000) was dissolved in 21.5 g of ion-exchanged water. 0.5 g was added under cooling and stirring, and the pH was adjusted to 4.8. A reactor equipped with a stirrer, a nitrogen aeration tube and a temperature controller was charged with 60.0 g of the aqueous polyethyleneimine solution obtained by the neutralization operation. Separately, 25.0 g of a 60% aqueous solution of acrylic acid, 90.0 g of a 50% solution of acrylamide, 18.4 g of sodium chloride and 34.6 g of ion-exchanged water were added. While replacing with nitrogen, a 10% by weight aqueous solution of 2,2 azobis (N, N-dimethyleneisobutylamidine) dihydrochloride was added as a polymerization initiator at 800 ppm by weight per monomer, and polymerization was carried out at 36 ° C for 18 hours with stirring. . As a result, a polymer dispersion of fine particles having a particle size of 10 to 100 μm was obtained (Sample 1). The viscosity of the resulting polymer dispersion was measured by a B-type viscometer, and the weight average molecular weight was measured by a molecular weight measuring device (DLS-7000 manufactured by Otsuka Electronics Co., Ltd.) by a static light scattering method.
[0039]
[Examples 2 to 6]
In the same manner as described above, monomers having the composition shown in Table 1 were charged so as to have the monomer concentration shown in Table 1, and polymerization was carried out to obtain water-soluble polymer dispersions (Sample-2 to Sample-6). ). The composition is shown in Table 1 and the results are shown in Table 2.
[0040]
Embodiment 7
In a four-neck separable flask equipped with a thermometer, a stirrer, and a dropping funnel, 146.6 g of epichlorohydrin and 29.6 g of ion-exchanged water were charged, and 123.8 g of a 50% by weight aqueous solution of dimethylamine was added to 40 to 45 g. The mixture was added dropwise at 2 ° C. over 2 hours, and after completion of the addition, the mixture was reacted at 45 ° C. for 1 hour.
[0041]
Next, to a separable flask equipped with a thermometer and a stirrer, 23.3 g of 100% polyethyleneimine (weight average molecular weight; 10,000) and 60.0 g of ion-exchanged water were added, followed by stirring. 26.9 g of the polycation product was added, and the mixture was reacted at 28 ° C. for 45 minutes. When the increase in the viscosity of the reaction product was observed, 4.5 g of 75% sulfuric acid was added to stop the reaction. The weight average molecular weight was measured to be 50,000.
[0042]
Next, in a reactor equipped with a stirrer and a temperature controller, 60 g of the modified polyethyleneimine prepared by the above operation was collected, and the solution was neutralized to 5.5 with sulfuric acid. Thereafter, a polymer dispersion of fine particles, Sample-7, was obtained in the same manner as in Examples 1 to 6. The composition is shown in Table 1 and the results are shown in Table 2.
[0043]
[Comparative Examples 1-4]
As the water-soluble polymer constituting the dispersion medium used in the polymerization, (2; dimethyldiallylammonium chloride polymer, molecular weight 100,000 (Comparative Examples 1 to 3), (2; polyethylene glycol # 5,000, Table 4 shows the composition and Table 2 shows the results.
[0044]
[Comparative Example 5]
In a four-necked 500 ml separable flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube, 93.7 g of deionized water, 34.0 g of ammonium sulfate, 6.0 g of sodium chloride, 31.3 g of 60% acrylic acid. , 50% acrylamide: 143.8 g, respectively. Further, 22.5 g of a diallyldimethylammonium chloride polymer (molecular weight: 300,000) of 20% by weight (6.0% by weight of the monomer) was added. Thereafter, nitrogen is introduced from a nitrogen introduction tube while stirring to remove dissolved oxygen. During this time, the internal temperature is adjusted to 30 ° C. by a constant temperature water bath. Thirty minutes after the introduction of nitrogen, 2.6 g (based on 0.07% by weight of monomer) of a 2% by weight aqueous solution of 2% by weight of ammonium peroxodisulfate and ammonium bisulfite was added in this order to initiate polymerization. Eight hours after the start of the polymerization, the same amount of the above-mentioned initiator was added, and 1.3 g of the initiator was added 6 hours later, and the reaction was completed in 15 hours. The molar ratio of acrylic acid to acrylamide in this sample was 25:75, and the viscosity was 550 mPa · s. As a result of microscopic observation, it was found that the particles had a size of 5 to 20 μm. The weight-average molecular weight measured was 4,000,000. This is designated as Comparison-5.
[0045]
[Table 1]

AAM: acrylamide, DMM: N, N-dimethylaminoethyl methacrylate DMA: N, N-dimethylaminoethyl acrylate, AAC: acrylic acid, IA: itaconic acid, (1 coexisting polymer; polyethyleneimine, (2 coexisting high Molecule: polyethyleneimine modified product, (3 coexisting polymer; dimethyldiallylammonium chloride polymer, (4 coexisting polymer; polyethylene glycol # 5,000, coexisting polymer addition amount; relative to monomer weight%, coexisting salt concentration; (A) sodium chloride, (b) sodium sulfate, (c) ammonium sulfate, (d) potassium chloride
[Table 2]

Dispersion viscosity: mPa · s, molecular weight unit: 10,000
Embodiments 8 to 14
After disintegrating the cardboard with a pulper, it was beaten with a Niagara-type beater, and the liquid band 2 was applied to a cardboard paper adjusted to 400 mL of Canadian Standard Freeness (CFS). %, The pH of the pulp slurry was adjusted to pH 5.8 with a 5.0% aqueous sodium carbonate solution, and a commercially available anionic polyacrylamide-based paper strength enhancer was added to the pulp at 0.2%, and the mixture was stirred and homogenized. Mixed. After diluting the obtained waste paper slurry to 0.5% and measuring the papermaking pH, 1 L was placed in a tappi standard sheet machine (1/16 m2) and a paper having a dry basis weight of 80 g / m2 was made. did. A filter paper and a cut plate were placed on the wet sheet on the wire, cuticle was applied three times, and the wet paper was transferred to the filter paper. This was designated as layer A. Next, similarly, paper having a dry basis weight of 80 g / m2 was made, the wet paper together with the wire was placed on a direct reading balance, and Samples 1 to 7 synthesized in Examples 1 to 7 were subjected to a predetermined method described in Table 3. A dispersion prepared by diluting to a diluted concentration was spray-coated from a 10.0 g nozzle at a pressure of 2.5 atm. This was designated as layer B.
[0048]
The layer A was combined with the layer B with the filter paper attached, and then the filter paper was peeled off. This was returned to the sheet machine together with the wire, the sheet machine was filled with water, and the water filled under the wire was drained to dehydrate under reduced pressure. A new filter paper was placed on the sheet machine, and cuticle roll was applied three times. Transferred to filter paper. The transferred wet paper was sandwiched between two filter papers, pressed at a pressure of 3 Kg / m2 for 5 minutes, and dried with a rotary drier to obtain a laminated paper. After humidity-conditioning the obtained laminated paper, J-TAPPI paper pulp test method NO. T-peel strength (gf / 5 cm) and internal strength were measured according to 19-77. Table 3 shows the dilution concentration and application amount together with the measurement results.
[0049]
[Comparative Examples 5 to 10]
For comparison, tests were performed using Comparative-1 to Comparative-5 in Table 2 and potato starch (Comparative-6) used in a papermaking site. Table 3 shows the results.
[0050]
[Table 3]

Dilution concentration: weight%, coating amount: g / m2, T-peel strength: gf / 5 cm,
Internal strength: Kg
[0051]
Examples 15 to 21
A papermaking test was carried out using a papermaking raw material pH 6.23 mainly composed of LBKP, a total ss content of 2.37% and an ash content of 0.41%. A pulp concentration of 0.9% by weight was diluted with tap water, and a paper having a basis weight of 70 g / m2 was formed using a TAPPI standard sheet machine (1/50). As additive chemicals, neutral rosin size, 0.2% (vs. papermaking dry matter, the same applies hereinafter), sulfuric acid band 1.0%, 0.2% for each of Samples 1 to 7 in Table 2 to improve yield As an agent, cationic polyacrylamide (molecular weight: 7.5 million, cation equivalent value: 2.80 meq / g) was added at 0.015% to the raw material for papermaking, each in this order at intervals of 15 seconds. Hereinafter, a test was performed by the same operation as in Examples 8 to 14. Table 4 shows the results.
[0052]
[Comparative Examples 11 to 15]
As a comparison, a test was performed by the same operation using Comparative-2 to Comparative-5 in Table 2 and the potato starch (Comparative-6). Table 4 shows the results.
[0053]
[Table 4]

Dilution concentration: weight%, coating amount: g / m2, T-peel strength: gf / 5 cm,
Internal strength: Kg
[0054]
Embodiments 22 to 28
A papermaking test was carried out using used newspaper, pH 6.02, total ss content 2.6%, and ash content 0.15%. A pulp concentration of 0.9% by weight was diluted with tap water, and a paper having a basis weight of 70 g / m2 was formed using a TAPPI standard sheet machine (1/50). Emulsion rosin size 0.1%, sulfate band 2.5%, 0.2% each of Sample-1 to Sample-7 in Table 2 as additive chemicals, and cationic polyacrylamide (molecular weight: 750) as a retention aid (Equivalent value of cation, 2.80 meq / g) was added to the papermaking raw material at 0.015%, in this order, at intervals of 15 seconds. Hereinafter, a test was performed by the same operation as in Examples 8 to 14. Table 5 shows the results.
[0055]
[Comparative Examples 16 to 19]
As a comparison, a test was performed in the same manner as in Table 2 using Comparative-3 to Comparative-5 and the potato starch (Comparative-6). Table 5 shows the results.
[0056]
[Table 5]

Dilution concentration: weight%, coating amount: g / m2, T-peel strength: gf / 5 cm,
Internal strength: Kg

Claims (8)

A water-soluble polymer comprising one or more ionic or non-ionic fine particles having a particle diameter of 100 μm or less selected from cationic, amphoteric, anionic and nonionic, and polyalkyleneimine and / or polyalkylene An adhesive for laminated paper comprising a dispersion in which an imine-modified product coexists in an aqueous salt solution. The dispersion comprises 1 to 50 mol% of a monomer represented by the following general formula (1) and / or (2), 0 to 50 mol% of at least one of the monomers represented by the following general formula (3), A monomer mixture composed of 50 to 99 mol% of a water-soluble nonionic monomer is stirred and mixed with a polyalkyleneimine and / or a modified polyalkyleneimine, and is subjected to dispersion polymerization in a salt aqueous solution. An adhesive for laminated paper, comprising the dispersion according to claim 1.

General formula (1)
R1 is hydrogen or a methyl group, R2 and R3 are alkyl groups, alkoxy groups or benzyl groups having 1 to 3 carbon atoms, and R4 is hydrogen, alkyl groups, alkoxy groups or benzyl groups having 1 to 3 carbon atoms. But it's fine. A represents oxygen or NH, B represents an alkylene group or an alkoxylen group having 2 to 4 carbon atoms, and X1 represents an anion, respectively.

General formula (2)
R5 represents hydrogen or a methyl group, R6 and R7 represent an alkyl group having 1 to 3 carbon atoms, an alkoxy group or a benzyl group, and X2 represents an anion.

General formula (3)
R8 is hydrogen, a methyl group or a carboxymethyl group, Q is SO3, C6H4SO3,
CONHC (CH3) 2CH2SO3, C6H4COO or COO, R9 is hydrogen or COOY2, Y1 or Y2 is hydrogen or cation The dispersion is prepared by stirring a monomer mixture comprising 2 to 50 mol% of one or more of the monomers represented by the general formula (3) and 50 to 98 mol% of a water-soluble nonionic monomer. The adhesive for laminated paper comprising the dispersion according to claim 1, wherein the adhesive is produced by dispersion polymerization in an aqueous salt solution in the presence of a modified alkyleneimine and / or a polyalkylenimine. The dispersion is prepared by dispersing a monomer (mixture) composed of at least one of the water-soluble nonionic monomers in the presence of a polyalkyleneimine and / or a modified polyalkyleneimine in a salt aqueous solution with stirring. An adhesive for laminated paper, comprising the dispersion according to claim 1, which is manufactured. The said polyalkyleneimine modified material has a structural unit represented by the following general formula (4) and / or (5), The laminated paper for dispersion papers of Claims 1-4 characterized by the above-mentioned. adhesive.

General formula (4)

General formula (5)
Here, p in the formulas (4) and (5) is an integer of 0 to 20, R10 to R17 are hydrogen, an alkyl group having 1 to 3 carbon atoms, a hydroxyalkyl or benzyl group, and X3 to X6 are negative. It is an ion. The polyalkylenimine modified product is a reaction product of a polyalkylenimine or a polyalkyleneimine and a polyamine mixture and a polycationic substance represented by the following general formula (6) and / or (7). Item 6. An adhesive for laminated paper comprising the dispersion according to any one of Items 1 to 5.

General formula (6)

General formula (7)
Wherein P in the formulas (6) and (7) is an epoxy group or a halohydrin group, p is an integer of 0 to 20, and R18 to R26 are hydrogen, an alkyl group having 1 to 3 carbon atoms, a hydroxyalkyl group or benzyl. The groups X7 to X10 are anions. The adhesive for laminated paper comprising the dispersion according to any one of claims 1 to 5, wherein the modified polyalkyleneimine is cross-linked by a polycationic substance represented by the general formula (6). When producing two or more layers of laminated paper including a step of pressing and then drying the wet paper layer after the paper layer is formed, the wet paper layer surface before the lamination is claimed. A method for producing a laminated paper, comprising spraying an adhesive for a laminated paper comprising the dispersion liquid according to any one of 1 to 7.