JP4048612B2 - Mechanical pulp-containing paper and method for producing the same - Google Patents

Description

（式中、Ａは炭素数２又は３のアルキレン基、ＲはＨ又はＣＨ₃ 、Ｒ₁ はヒドロキシエチル基又はヒドロキシプロピル基、Ｒ₂ およびＲ₃ は炭素数１〜４のアルキル基、Ｘは陰イオンを表す。）
【０００５】
近年、森林保護の観点や、低コスト化の観点から、原料パルプ中に原料使用効率の良い機械パルプを配合して使用する紙の生産が増加しており、一方、抄紙系の中性化の進行に伴い、ケテンダイマー系サイズ剤や置換環式ジカルボン酸無水物系サイズ剤、中性抄紙用ロジン系サイズ剤等の中性サイズ剤が比較的広く使用されるようになってきており、機械パルプを配合したパルプ原料を使用し、中性サイズ剤でサイジングを行う抄紙系において、ピッチ障害を抑制するとともに、得られた紙のサイズ性に優れる紙の製造方法が切に望まれている。
本発明の第１の目的は、ピッチ障害を抑制できる機械パルプ含有紙及びその製造方法を提供することにある。
本発明の第２の目的は、サイズ性の優れた機械パルプ含有紙及びその製造方法を提供することにある。
本発明の第３の目的は、中性サイズ剤の歩留まりを向上させることができる機械パルプ含有紙及びその製造方法を提供することにある。
【０００６】
【問題を解決するための手段】
本願発明者らは、上記目的を達成するために鋭意検討した結果、（１）、乾燥重量基準で機械パルプを少なくとも５重量％含有する製紙用パルプを用いて中性サイズ剤によりサイジングした機械パルプ含有紙において、下記（Ａ）５０〜９５重量％及び下記（Ｂ）５〜５０重量％の各単量体に対応する構成単位の結合体を有し、かつ４級アンモニウム塩を有するビニル系共重合体であるカチオン性ポリマーを添加物として上記機械パルプの乾燥重量に対して０．０３〜１重量％含有する機械パルプ含有紙を提供するものである。
（Ａ）スチレン系単量体及びアルキル（メタ）アクリレートからなる群より選択された少なくとも１種の疎水性単量体
（Ｂ）ジアルキルアミノアルキル（メタ）アクリルアミド及びジアルキルアミノアルキル（メタ）アクリレートからなる３級アミノ基を有する単量体並びにそれぞれの４級化物からなる４級アンモニウム塩を有する単量体の群より選ばれた少なくとも１種のカチオン性単量体
また、本発明は、（２）、上記（Ｂ）成分の一部に上記（Ａ）及び（Ｂ）成分以外のその他のビニル系単量体を用いる上記（１）の機械パルプ含有紙、（３）、中性サイズ剤がケテンダイマー系サイズ剤、置換環式ジカルボン酸無水物系サイズ剤及び中性抄紙用ロジン系サイズ剤からなる群から選ばれる少なくとも１種である上記（１）又は（２）の機械パルプ含有紙、（４）、乾燥重量基準で機械パルプを少なくとも５重量％含有する製紙用パルプを原料とし、ｐＨ６〜９で中性サイズ剤を使用してサイジングする抄紙工程を有する機械パルプ含有紙の製造方法において、下記（Ａ）５０〜９５重量％及び下記（Ｂ）５〜５０重量％含有する単量体から得られるビニル系共重合体であって、下記（Ｂ）成分として３級アミノ基を有する単量体を使用する場合は該ビニル系共重合体の重合過程及び重合後の少なくとも一方において４級化することがある４級アンモニウム塩を有するカチオン性ポリマーを含有する添加剤を上記抄紙工程において使用し、かつ該カチオン性ポリマーを上記機械パルプの乾燥重量に対して０．０３〜１重量％使用する機械パルプ含有紙の製造方法、
（Ａ）スチレン系単量体及びアルキル（メタ）アクリレートからなる群より選択された少なくとも１種の疎水性単量体
（Ｂ）ジアルキルアミノアルキル（メタ）アクリルアミド及びジアルキルアミノアルキル（メタ）アクリレートからなる３級アミノ基を有する単量体並びにそれぞれの４級化物からなる４級アンモニウム塩を有する単量体の群より選ばれた少なくとも１種のカチオン性単量体
（５）、上記（Ｂ）成分の一部に上記（Ａ）及び（Ｂ）成分以外のその他のビニル系単量体を用いる上記（４）の機械パルプ含有紙の製造方法を提供するものである。
【０００７】
次に本発明を詳細に説明する。
本発明において、機械パルプとは、機械的に木材を繊維化して製造したパルプであり、砕木パルプ、リファイナー砕木パルプ、加圧砕木パルプ、サーモメカニカルパルプのような高収率パルプや、これらの高収率パルプを原料とした紙を離解脱墨した脱墨パルプ等をいう。
【０００８】
また、中性サイズ剤とは、中性域の抄紙系で使用されるサイズ剤であり、ケテンダイマー系サイズ剤、置換環式ジカルボン酸無水物系サイズ剤、中性抄紙用ロジン系サイズ剤等が挙げられ、これらは１種又は少なくとも２種混合して使用でき、公知一般の市販品は使用できる。ケテンダイマー系サイズ剤及び／または置換環式ジカルボン酸無水物系サイズ剤のパルプスラリーに対する添加率は、乾燥パルプに対し０．０１〜１％が好ましく、より好ましくは０．０２〜０．５％である。ケテンダイマー系サイズ剤及び／または置換環式ジカルボン酸無水物系サイズ剤の添加率が、０．０１％より少ないとサイズ効果が十分でない場合があり、１％より多くなるとコスト高や、抄紙系の汚れの原因となる場合がある。
【０００９】
中性抄紙用ロジン系サイズ剤としては、特願平９−６１７６２号に記載されているようなロジンの一部を例えば疎水化する変性をしたタイプのものは使用できる。中性抄紙用ロジン系サイズ剤のパルプスラリーに対する添加率は、乾燥パルプに対し０．０１〜２％が好ましく、より好ましくは０．０５〜１％である。添加率が、０．０１％より少ないとサイズ効果が十分でない場合があり、２％より多くなるとコスト高や、抄紙系の汚れの原因となる場合がある。ケテンダイマー系サイズ剤、置換環式ジカルボン酸無水物系サイズ剤及び中性抄紙用ロジン系サイズ剤の中では、ケテンダイマー系サイズ剤を使用することが、本発明に用いるカチオン性ポリマーを含有する添加剤と併用する場合に、ピッチ障害の抑制効果、サイズ性の向上効果の点においてより好ましい。
【００１０】
本発明に用いるカチオン性ポリマーは、上記（Ａ）成分５０〜９５重量％及び上記（Ｂ）成分５〜５０重量％の各単量体に対応する構成単位の結合を有し、かつ４級アンモニウム塩を有するビニル系共重合体であるが、上記（Ａ）成分５０〜９５重量％及び上記（Ｂ）成分５〜５０重量％含有する単量体組成から得られるビニル系共重合体であるカチオン性共重合体であって、この（Ｂ）成分として３級アミノ基を有する単量体を使用する場合には、このカチオン性共重合体の重合過程及び重合後の少なくとも一方で４級化剤で４級化することがある。上記（Ｂ）成分として３級アミノ基を有する単量体を使用した場合でも、その４級化した単量体を使用した場合には、カチオン性共重合体の重合過程及び重合後の少なくとも一方で４級化剤で４級化しなくてもよい場合がある。
上記（Ａ）成分のスチレン系単量体としては、スチレン、ビニルトルエン、α−メチルスチレン、ジビニルベンゼン等を挙げることができ、これらは１種又は少なくとも２種用いることができる。
また、上記（Ａ）成分のアルキル（メタ）アクリレート（アルキルアクリレート及びアルキルメタクリレートの少なくとも１種を示し、以下、（メタ）の付加された化合物はこれを準用する。）としては、メチル（メタ）アクリレート、エチル（メタ）アクリレート、ブチル（メタ）アクリレート、シクロヘキシル（メタ）アクリレート、２−エチルヘキシル（メタ）アクリレート、ラウリル（メタ）アクリレート、ステアリル（メタ）アクリレート等の低級アルキル基、高級アルキル基又はシクロアルキル基を有する単量体が挙げられ、これらは１種又は少なくとも２種用いることができる。
【００１１】
上記（Ｂ）成分の３級アミノ基を有する単量体としてのジアルキルアミノアルキル（メタ）アクリルアミドとしてはN,N-ジメチルアミノプロピル（メタ）アクリルアミド等が挙げられる。また、ジアルキルアミノアルキル（メタ）アクリレートとしてはN,N-ジメチルアミノエチル（メタ）アクリレート等が挙げられる。
上記（Ｂ）成分の４級アンモニウム塩を有する単量体としては、上記の３級アミノ基を有する単量体を、アルキルハライド、ベンジルハライド、アルキルトシレート、アルキルメシレート、ジアルキルカーボネート、ジメチル硫酸、エピハロヒドリン等の４級化剤との反応で４級アンモニウム塩とする方法や、３−クロロ−２−ヒドロキシプロピルトリメチルアンモニウムクロライド等の４級化剤との反応でビス４級アンモニウム塩とする方法等を挙げることができる。
これらの単量体は１種又は少なくとも２種用いることができる。
本発明のカチオン性ポリマーを得るには、上述したように、上記（Ｂ）成分のジアルキルアミノアルキル（メタ）アクリルアミド及び／又はジアルキルアミノアルキル（メタ）アクリレートの３級アミノ基を有する単量体を４級化物とした後、上記（Ａ）成分の疎水性単量体と共重合する方法、上記（Ｂ）成分の３級アミノ基を有する単量体と上記（Ａ）成分の疎水性単量体を共重合する途中で４級化反応を行う方法、あるいはその共重合後に４級化反応を行う方法の何れでもよいが、カチオン性ポリマーを構成する全単量体に対する上記（Ａ）成分の疎水性単量体の割合は５０〜９５重量％であり、好ましくは５５〜９０重量％である。疎水性単量体の割合が、５０重量％より少ない場合、あるいは、９５重量％より多い場合はピッチ障害の抑制の効果が得られ難く、紙のサイズ性も向上し難い。上記（Ｂ）成分の３級アミノ基を有する単量体及び／又はその４級化単量体の割合は５〜５０重量％で、好ましくは１０〜４５重量％である。これらの割合が、５重量％より少ない場合、あるいは、５０重量％より多い場合はピッチ障害の抑制の効果が得られ難く、紙のサイズ性も向上し難い。また、ジアルキルアミノアルキル（メタ）アクリルアミド４級化物を共重合単位に有する共重合体の方が、ジアルキルアミノアルキル（メタ）アクリレート４級化物を共重合単位に有する共重合体に比べて好ましく、耐加水分解性も良い。
【００１２】
本発明においては、上記の単量体の他に、所望により、ジアルキルアミノアルキル（メタ）アクリルアミド４級化物及び／又はジアルキルアミノアルキル（メタ）アクリレート４級化物の一部を置き換える方法で（メタ）アクリルアミド、（メタ）アクリロニトリル、オレフィン、ビニルエーテル、アリルエステル、ビニルケトン、ビニルスルホンアミド、N-ビニル-2-ピロリドン、（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-アルキル（メタ）アクリルアミド、メチレンビスアクリルアミド、アリルアミン、ジアリルアミン、ビニルピリジン、ビニルホルムアミド、ビニルアセトアミド、ビニルアミン誘導体等のビニル系単量体を併用することができる。これらは１種又は少なくとも２種併用することができる。
【００１３】
共重合体の重合方法としては、上記単量体をラジカル重合開始剤の存在下で溶液重合法あるいは塊状重合法、乳化重合法、分散重合法等を用いて重合反応を行う。必要に応じて溶剤を留去し、所定の固形分濃度に調整することによりカチオン性ポリマー水性液を得ることができる。これをそのまま添加剤としてもよいが、さらに他の添加物を加えたものを添加剤としてもよい。
カチオン性ポリマーは、パルプ原料中に配合された機械パルプの乾燥重量に対して０．０３〜１重量％の割合でパルプ原料に添加する。カチオン性ポリマーの添加率が、機械パルプの乾燥重量に対して０．０３％より少ないとピッチ障害の抑制効果や紙へのサイズ性の付与が十分でなく、１％より多くなるとコスト高となる。
【００１４】
本発明に用いるカチオン性ポリマーを含有する添加剤及び中性サイズ剤の抄紙工程における添加場所については制限されることはないが、パルプスラリー中でそれらが十分分散されることが望ましい。添加順序についても制限はなく、添加剤が先で、次いで中性サイズ剤の順に加えても良く、この逆でも良く、また、これらを同時に加えても良く、さらにこれらの混合液を加えても良い。また、填料、乾燥紙力増強剤、歩留り向上剤、濾水性向上剤等の添加剤も、各々の紙種の要求される物性を発揮するために必要に応じて使用しても良い。
また、本発明における抄紙ｐＨは６〜９の範囲である。ｐＨが６より低いとケテンダイマー系サイズ剤や置換環式ジカルボン酸無水物系サイズ剤のサイズ効果が低下する。ｐＨが９より高い場合においても、中性サイズ剤のサイズ効果が低下し、さらに、機械パルプの黄変等の問題が有り、実用的でない。
【００１５】
【発明の実施の形態】
疎水性単量体として▲１▼スチレン、2-エチルヘキシル（メタ）アクリレート、メチルメタクリレート、▲２▼３級アミノ基を有する単量体として N,N- ジメチルアミノプロピル（メタ）アクリルアミド、N,N-ジメチルアミノエチル（メタ）アクリレートを使用し、これら▲１▼の少なくとも１種及び▲２▼の少なくとも１種、好ましくは▲１▼のスチレン及び▲２▼の N,N- ジメチルアミノプロピルアクリルアミドを含有する単量体を共重合させ、その共重合体をエピハロヒドリンで４級化したカチオン性ポリマー水溶液を調製する。これらについて、共重合割合を、（ａ）▲１▼の単量体を５０〜８５重量％、▲２▼の単量体をエピハロヒドリンで４級化した単量体として１５〜５０重量％としたカチオン性ポリマー、また、（ｂ）上記▲１▼の少なくとも１種、好ましくはスチレンを含有する単量体５５〜６０重量％、▲２▼の4 級アンモニウム塩を有する単量体の少なくとも１種としてアルキルハライドで4 級化したN,N-ジメチルアミノプロピルメタクリルアミドを４０〜４５重量％共重合させたカチオン性ポリマー、（ｃ）上記▲１▼の少なくとも１種、好ましくはスチレンを含有する単量体５５〜６０重量％、▲２▼の少なくとも１種、好ましくはアルキルハライドで4 級化したN,N-ジメチルアミノプロピルメタクリルアミド３９〜４１重量％、（メタ）アクリアミド１〜４重量％を共重合させたカチオン性ポリマーをそれぞれ含有するカチオン性ポリマー水性液からなる添加剤を調製する。
乾燥重量基準で機械パルプの含有率１０〜９０重量％とした原料パルプを用い、ケテンダイマー系サイズ剤の添加量を０．１〜０．２重量％（対乾燥パルプ）とし、上記添加剤を上記（ａ）〜（ｃ）のカチオン性ポリマー分として０．０２〜０．０８重量％（対機械パルプ）添加し、抄紙する。また、ケテンダイマー系サイズ剤の代わりに、アルケニルコハク酸無水物系サイズ剤を０．１〜０．２重量％（対乾燥パルプ）用い、機械パルプの含有率を８〜１２重量％とし、上記添加剤を上記（ａ）〜（ｃ）のカチオン性ポリマー分として０．５〜０．９重量％（対機械パルプ）添加し、抄紙する。また、アルケニルコハク酸無水物系サイズ剤の代わりに、中性抄紙用ロジン系サイズ剤を０．２〜０．４重量％（対乾燥パルプ）用い、機械パルプの含有率を２０〜４０重量％とし、上記添加剤を上記（ａ）〜（ｃ）のカチオン性ポリマー分として０．２５〜０．４５重量％（対機械パルプ）添加し、抄紙する。
このようにすると、サイズ剤定着量が多く、ロール等の汚れが少ないとともに、得られた紙はサイズ度が良くなるが、その理由は、上記（ａ）〜（ｃ）のカチオン性ポリマーを含有する添加剤の使用により、機械パルプに付随するピッチや中性サイズ剤が紙料中に保持され易く、したがってフェルトやロール等の抄紙用具に付着し難くなるためと解される。これは、上記（ａ）〜（ｃ）のカチオン性ポリマーが疎水性単量体に対応する構成単位からなる疎水性部分と、カチオン性単量体に対応する構成単位からなる親水性部分をバランス良く有しており、その疎水性部分とピッチや中性サイズ剤の疎水性部分との親和性が良く、その親水性部分は水との親和性が良いためと考えられるが、この考え方に限られるものではない。
【００１６】
【実施例】
以下本発明の実施例を挙げて具体的に説明するが、本発明はこれら実施例のみに限定されるものではない。なお、以下の実施例、比較例において、％とあるものは特に断わりの無い限り、固形分重量％を意味する。
【００１７】
実施例用カチオン性ポリマー水性液（添加剤）の製造例１
攪拌機、温度計、冷却管を備え付けた１リットルの４つ口フラスコに、スチレン７２．９ｇ、２−エチルヘキシルアクリレート９．２ｇ、N-エチル-N,N- ジメチル−３−（メタクリロイルアミノプロピル）アンモニウムブロマイド５７．６ｇ、５０％アクリルアミド水溶液７．１ｇ、イソプロピルアルコール１５０ｇ、アゾビスイソブチロニトリル２ｇを加え、窒素気流中、８０℃で５時間反応した。次に水４２２ｇを加え、よく攪拌して水に分散させ、冷却し、カチオン性ポリマー水性液Ａを７００ｇ得た。その固形分は２０％であった。全単量体に対する各単量体の重量百分率は、スチレン５０．９％、２−エチルヘキシルアクリレート６．４％、N-エチル-N,N-ジメチル−３−（メタクリロイルアミノプロピル）アンモニウムブロマイド４０．２％、アクリルアミド２．５％であり、スチレンと２−エチルヘキシルアクリレートを合わせた疎水性単量体の合計は５７．３％である。使用した単量体の重量組成を表１に示した。
【００１８】
実施例用カチオン性ポリマー水性液（添加剤）の製造例２
攪拌機、温度計、冷却管を備え付けた１リットルの４つ口フラスコに、スチレン８３．３ｇ、N,N-ジメチルアミノプロピルアクリルアミド３１．２ｇ、ベンゼン１１７ｇ、アゾビスイソブチロニトリル２ｇを入れ、窒素気流中、８０℃で５時間反応した。次に３％酢酸溶液４２３ｇを加え、９７℃まで加熱しベンゼンを留去した。留去後、留去した分の水を加え、エピクロルヒドリン１８．５ｇを加え、８０℃で３時間４級化反応を行った後、冷却しカチオン性ポリマー水性液Ｂを６７０ｇ得た。その固形分は２０％であった。使用した単量体の重量組成を表１に示した。
【００１９】
実施例用カチオン性ポリマー水性液（添加剤）の製造例３〜６
表１に示す単量体の種類及び重量組成を変える以外は、実施例用カチオン性共重合体の製造例２と同様にしてカチオン性ポリマー水性液Ｃ、Ｄ、Ｅ、Ｆを製造した。共重合体の固形分濃度は２０％になるように調整した。使用した単量体の重量組成を表１に示した。
【００２０】
比較例用カチオン性ポリマー水性液（添加剤）の製造例１
特開昭５３−４１５０７号公報の実施例１に従い、次の様にしてN,N-ジメチル-N-(β- ヒドロキシエチル)-N-( β- メタクリルオキシエチル) アンモニウムアセテートのホモポリマーを製造した。１９．３部の氷酢酸、６０．５部の脱イオン水及び２８．６部の０．１５％ＦｅＳＯ₄ ・Ｈ₂ Ｏ水溶液を加圧釜に入れた。窒素で釜内容物から酸素を除き、６０℃に加熱し、ジメチルアミノエチルメタクリレート４７．８部、ペルオキソ硫酸アンモニウム９．８部を脱イオン水１１６．２部で溶解した水溶液及び二亜硫酸ナトリウム９．８部を脱イオン水１１６．２部で溶解した水溶液を３時間後に加えた。６０℃で更に３０分間保ち、次いで４０℃に下げ、その温度でエチレンオキサイド１４０．７部を徐々に添加し、カチオン性ポリマー水性液Ｇを得た。使用した単量体の重量組成を表１に示した。
【００２１】
比較例用カチオン性ポリマー水性液（添加剤）の製造例２、３
表１に示す単量体の種類及び重量組成に変える以外は、上記比較例用カチオン性重合体の製造例１の手順で、カチオン性ポリマー水性液Ｈ、Ｉの重合体を得た。
【００２２】
比較例用カチオン性ポリマー水性液（添加剤）の製造例４
表１に示す単量体の種類及び重量組成に変える以外は、実施例用カチオン性共重合体の製造例２と同様にして比較例用カチオン性ポリマー水性液Ｊを製造した。共重合体の固形分濃度は２０％になるように調整した。
【００２３】
【表１】

【００２４】
実施例１
砕木パルプ、サーモメカニカルパルプ、漂白広葉樹クラフトパルプを乾燥重量基準で５／５／９０の比率（機械パルプ１０％）で混合したパルプの２．５％パルプスラリー（カナディアン スタンダード フリーネス ３８０ｍｌ）を調製し、これに軽質炭酸カルシウム（タマパール１２１Ｓ、奥多摩工業株式会社製）を対乾燥パルプ１５％添加し、２分間攪拌後、硫酸バンドを対乾燥パルプ０．５％、両性澱粉（Ｃａｔｏ３２１０、日本ＮＳＣ株式会社製）を対乾燥パルプ０．６％、アルキルケテンダイマー系サイズ剤（ＡＳ２６３、日本ＰＭＣ株式会社製）を対乾燥パルプ０．１％、それぞれ攪拌しながらこの順で添加した。添加の間隔は１分間とした。その後カチオン性ポリマー水性液Ａをカチオン性ポリマー分として対乾燥パルプ０．００５％（対機械パルプ０．０５％）添加し、１分間攪拌した。さらに、得られた紙料をｐＨ８の希釈用水で０．２５％に希釈し、歩留り向上剤（ＮＲ１２ＭＬＳ、ハイモロック株式会社製）を対乾燥パルプ０．０２％添加し、３０秒間攪拌した。ここでの抄紙ｐＨは７．８であった。 ノーブルアンドウッド社製手抄き装置を使用し、得られた紙料から湿紙を作成した。抄紙温度は４５℃とした。湿紙をプレス後、１００℃のドラムドライヤーで80秒間乾燥し、目的とする手抄紙とした。坪量は７０ｇ／ｍ² に調整した。
【００２５】
作成した手抄紙につき、ＪＩＳ Ｐ−８１２２に準じ、抄紙直後および調湿１日後のステキヒトサイズ度を測定した。調湿条件は６５％ＲＨ、２０℃とした。また、熱分解ガスクロマトグラフにより、紙中アルキルケテンダイマー量を測定した。それらの結果を表２に示す。
【００２６】
また、抄紙機のプレスロールが汚れる現象を模した次の試験を行い、ピッチ障害の抑制効果を調べた。
すなわち、上記手抄き実験においてＡＳ２６３を２倍の０．２％とする。また、希釈用水による希釈濃度を０．７％とする以外は同様にして紙料を調製した。得られた紙料をロール汚れ試験機（抄紙装置の汚れを試験する試験装置であり、第１図に概略説明図を示す）に供給して２時間後及び５時間後のプレスロールの汚れ具合を調べた。汚れの評価は目視で行い、プレスロールの汚れが最も著しいものを「１０」、汚れ無しを「０」とする指数を用いた段階評価で表示した。その結果を表２に示す。
なお、上記ＡＳ２６３の添加率を２倍にしたのは、効果の差を際立たせるためであり、これらの通常の添加量の抄紙系における抄紙を長時間続けた場合とは相関関係がある。
【００２７】
なお、第１図は、紙料投入口１から紙料をワイヤー装置２に順次供給し、重力脱水した後、第１ロール３と主ロール４でプレスし、さらに主ロール４と第２ロール５でプレスして脱水した湿紙６を得る装置を示すもので、その具体的構造は以下の通りである。
主ロール：直径約２５ｃｍ、幅約４０ｃｍ
第１ロール：直径約１４．５ｃｍ、幅約４０ｃｍ
第２ロール：直径約１０ｃｍ、幅約４０ｃｍ
ワイヤー：幅約３５ｃｍ
この装置において、第１ロール、第２ロールの主ロールに対する圧はそれぞれのロールの自重によるもので、第２ロール通過後の湿紙の水分率は６０％である。試験条件は、抄速１．５ｍ／分、紙料温度４５℃、ロール温度３４〜３６℃、抄幅１５ｃｍとした。第２ロールに対する汚れを目視により調べた。
【００２８】
実施例２
砕木パルプ、サーモメカニカルパルプ、漂白広葉樹クラフトパルプを乾燥重量基準で１５／１５／７０の比率（機械パルプ３０％）で混合したパルプの２．５％パルプスラリー（カナディアン スタンダード フリーネス ２８０ｍｌ）を使用し、カチオン性ポリマー水性液Ａの添加率をカチオン性ポリマー分として対乾燥パルプ０．０２％（対機械パルプ ０．０６７％）とした以外は実施例１と同様にして手抄紙を作成し、サイズ度の測定を行い、サイズ剤の定着量を求めた。また、実施例１と同様にしてロール汚れ試験を行った。それらの結果を表２に示す。
【００２９】
実施例３〜７
カチオン性ポリマー水性液Ａに代えて、各々カチオン性ポリマー水性液Ｂ、Ｃ、Ｄ、Ｅ、Ｆを使用したこと以外は実施例２と同様にして手抄紙を作成し、実施例２と同様にサイズ度の測定を行い、サイズ剤の定着量を求めた。また、実施例２と同様にロール汚れ試験を行った。それらの結果を表２に示す。
【００３０】
実施例８
砕木パルプ、サーモメカニカルパルプ、高収率パルプを原料とした紙の脱墨パルプ、漂白広葉樹クラフトパルプを乾燥重量基準で３０／３０／３０／１０の比率（機械パルプ９０％）で混合したパルプの２．５％パルプスラリー（カナディアン スタンダード フリーネス １９０ｍｌ）を使用し、上記ＡＳ２６３を対乾燥パルプ０．２％、カチオン性ポリマー水性液Ａのカチオン性ポリマー分としての添加率を対乾燥パルプ０．０３％（対機械パルプ０．０３３％）としたこと以外は実施例１と同様にして手抄紙を作成し、実施例１と同様にしてサイズ度の測定を行い、サイズ剤の定着量を求めた。また、実施例１と同様にロール汚れ試験を行った。それらの結果を表２に示す。
【００３１】
比較例１〜４
カチオン性ポリマー水性液Ａに代えて、各々カチオン性ポリマー水性液Ｇ、Ｈ、Ｉ、Ｊを使用したこと以外は実施例２と同様にして手抄紙を作成し、実施例２と同様にサイズ度の測定を行い、サイズ剤の定着量を求めた。また、実施例２と同様にロール汚れ試験を行った。それらの結果を表２に示す。
【００３２】
比較例５
カチオン性ポリマー水性液Ａのカチオン性ポリマー分としての添加率を対乾燥パルプ０．００５％（対機械パルプ０．０１７％）としたこと以外は実施例２と同様にして手抄紙を作成し、実施例２と同様にサイズ度の測定を行い、サイズ剤の定着量を求めた。また、実施例２と同様にロール汚れ試験を行った。それらの結果を表２に示す。
【００３３】
比較例６
カチオン性ポリマー水性液Ａのカチオン性ポリマー分としての添加率を対乾燥パルプ０．０２％（対機械パルプ０．０２２％）としたこと以外は実施例８と同様にして手抄紙を作成し、実施例８と同様にサイズ度の測定を行い、サイズ剤の定着量を求めた。また、実施例８と同様にロール汚れ試験を行った。それらの結果を表２に示す。なお、ロール汚れ試験の評価は「１０」であったが、比較例１よりもその程度は劣っていたので「１０（以上）」とした。
【００３４】
【表２】

【００３５】
実施例１０
アルキルケテンダイマー系サイズ剤に代えて、アルケニルコハク酸無水物系サイズ剤（ＡＳ２９０、日本ＰＭＣ株式会社製）を対乾燥パルプ０．１％使用し、カチオン性ポリマー水性液Ａの添加率を対乾燥パルプ０．０７％（対機械パルプ０．２３％）としたこと以外は実施例２と同様にして手抄紙を作成し、実施例２と同様にサイズ度の測定を行った。抄紙ｐＨは７．８であった。熱分解ガスクロマトグラフにより、得られた紙の中のアルケニルコハク酸無水物量を測定し、ケテンダイマー系サイズ剤を使用した上記実施例の場合と同様にして、サイズ剤の定着量を求めた。また、アルキルケテンダイマー系サイズ剤に代えて、上記ＡＳ２９０を対乾燥パルプ０．２％使用したこと以外は上記実施例１と同様にして、ロール汚れ試験を行った。その評価方法は実施例１に準じて行った。それらの結果を表３に示す。
【００３６】
実施例１１〜１５
カチオン性ポリマー水性液Ａに代えて、各々カチオン性ポリマー水性液Ｂ、Ｃ、Ｄ、Ｅ、Ｆを使用したこと以外は実施例１０と同様にして手抄紙を作成し、実施例１０と同様にサイズ度の測定を行い、サイズ剤の定着量を求めた。また、実施例１０と同様にロール汚れ試験を行った。それらの結果を表３に示す。
【００３７】
比較例７〜１０
カチオン性ポリマー水性液Ａに代えて、各々カチオン性ポリマー水性液Ｇ、Ｈ、Ｉ、Ｊを使用したこと以外は実施例１０と同様にして手抄紙を作成し、実施例１０と同様にサイズ度の測定を行い、サイズ剤の定着量を求めた。また、実施例１０と同様にロール汚れ試験を行った。それらの結果を表３に示す。
【００３８】
【表３】

【００３９】
実施例１６
硫酸アルミニウムの添加率を１．５％とし、アルキルケテンダイマー系サイズ剤に代えて中性抄紙用ロジン系サイズ剤（ＣＣ１６７、日本ＰＭＣ株式会社製）を対乾燥パルプ０．３％使用し、カチオン性ポリマー水性液Ａの添加率をカチオン性ポリマー分として対乾燥パルプ０．１％（対機械パルプ０．３３％）としたこと以外は実施例２と同様にして手抄紙を作成し、実施例２と同様にサイズ度の測定を行った。抄紙ｐＨは７．６であった。
手抄紙を酸性条件下でほぐし、エーテル抽出を行い、ゲル浸透クロマトグラフで有機相中のロジン成分量を測定し、ケテンダイマー系サイズ剤を使用した上記実施例１の場合と同様にして、サイズ剤の定着量を求めた。また、アルキルケテンダイマー系サイズ剤に代えて上記ＣＣ１６７を対乾燥パルプ０．５％使用したこと以外は上記実施例１と同様にして、ロール汚れ試験を行った。その評価方法は実施例１に準じて行った。それらの結果を表４に示す。
【００４０】
実施例１７〜２１
カチオン性ポリマー水性液Ａに代えて、各々カチオン性ポリマー水性液Ｂ、Ｃ、Ｄ、Ｅ、Ｆを使用したこと以外は実施例１６と同様にして手抄紙を作成し、実施例１６と同様にサイズ度の測定を行い、サイズ剤の定着量を求めた。また、実施例１６と同様にロール汚れ試験を行った。それらの結果を表４に示す。
【００４１】
比較例１１〜１４
カチオン性ポリマー水性液Ａに代えて、各々カチオン性ポリマー水性液Ｇ、Ｈ、Ｉ、Ｊを使用したこと以外は実施例１６と同様にして手抄紙を作成し、実施例１６と同様にサイズ度の測定を行い、サイズ剤の定着量を求めた。また、実施例１６と同様にロール汚れ試験を行った。それらの結果を表４に示す。
【００４２】
【表４】

【００４３】
以上の結果より、機械パルプを含有する原料パルプを用いた抄紙系において、実施例のものは比較例のものよりもピッチ抑制効果及び得られた紙のサイズ性が共に優れていることが分かる。即ち、機械パルプを配合した原料を使用し、中性サイズ剤でサイジングする場合、本発明に係わるカチオン性ポリマーを使用して抄造することにより、ピッチ障害の抑制や成紙のサイズ性の向上を図ることができる。
実施例１と比較例５、実施例２と比較例６のデータの対比から分かるように、配合する機械パルプの割合が高い場合、それに応じて、本発明に係わるカチオン性ポリマーの添加率も高くする必要がある。その作用機構は定かではないが、本発明に係わるカチオン性ポリマーは機械パルプ中のピッチ成分の凝集防止作用を有していると考えられる。サイズ剤定着量をみると実施例の方が、比較例のものよりも高い。このことはサイズ剤の歩留りが高くなることによって、ピッチ障害の一因となる可能性がある抄紙系中に滞留するサイズ剤やその加水分解物が減少すると共に、紙のサイズ度が向上しているためと考えられる。本発明に係わるカチオン性ポリマーは、一定量以上の疎水性部を有している点で、比較例のカチオン性ポリマーと異なるが、この一定量以上の疎水性部が、機械パルプを含有した抄紙系で中性サイズ剤を使用する条件下で、効果的に作用しているといえる。即ち、一定量以上の疎水性部を導入した本発明に係わるカチオン性ポリマーによって、従来ではなし得なかったレベルのピッチ障害の抑制ができると共に、成紙のサイズ度も向上させることができる。
【００４４】
【発明の効果】
本発明によれば、機械パルプを配合したパルプ原料を使用して中性サイズ剤でサイジングする際にピッチ障害を抑制できるとともに、中性サイズ剤の歩留まりを向上し、サイズ性の優れた機械パルプ含有紙及びその製造方法を提供することができる。
【図面の簡単な説明】
【図１】抄紙装置のロールの汚れを試験する試験装置である。[0001]
[Industrial application fields]
The present invention relates to a mechanical pulp-containing paper and a method for producing the same, and more specifically, contains a mechanical pulp capable of suppressing an obstacle due to pitch associated with a papermaking process using a mechanical pulp and giving an excellent sizing property to the paper. The present invention relates to paper and its manufacturing method.
[0002]
[Prior art]
Mechanical pulp is a pulp produced by mechanically converting wood into fiber, and contains a relatively large amount of poorly water-soluble adhesive substance mainly composed of organic substances such as resin called pitch. Therefore, in the paper making by neutral sizing agent using mechanical pulp, the product is produced by the pitch paper adhering to the paper making equipment such as felt, press roll, smoother roll, canvas stretch roll, etc. As a result, the paper is easily soiled by deposits of the pitch, so that a so-called pitch failure is easily caused.
In particular, neutral sizing is achieved using neutral sizing agents such as ketene dimer sizing agents, substituted cyclic dicarboxylic acid anhydride sizing agents such as alkenyl succinic anhydrides, and rosin sizing agents for neutral papermaking. If so, pitch disturbance may be more likely to occur. Since so-called reactive ketene dimers or substituted cyclic dicarboxylic acid anhydrides are easily hydrolyzed, some of them become hydrolysates in papermaking water before they settle on pulp fibers and develop size. And may form aggregates. If the agglomerates are sticky near the papermaking temperature, when the adhesive adheres to the surface of the felt or roll, it becomes a relatively hydrophobic adhesive component and the hydrophobicity of mechanical pulp. This is because the pitch further adheres due to its affinity and adhesiveness, and as a result, dirt accumulates on the felt and roll surfaces, and the wet paper that comes into contact with the pitch is easily stained. In addition, when using a rosin sizing agent for neutral papermaking, a relatively high addition rate is required to obtain a size level comparable to that of a ketene dimer sizing agent or a substituted cyclic dicarboxylic acid anhydride sizing agent. As a result, the portion that does not fix to the pulp fiber tends to increase, so-called yield deteriorates, and the solid component that is not fixed adheres to the surface of the felt or roll as in the above case, These are soiled and the wet paper is also easily soiled.
Such a pitch failure reduces the commercial value of the finished product, and if it is to be avoided, it is necessary to remove the pitch adhering to felts and rolls. It will be a serious problem that will lower.
[0003]
[Problems to be solved by the invention]
As a method for suppressing the pitch hindrance, a method using a pitch control agent comprising a specific amphoteric surfactant and a water-soluble cationic polymer as active ingredients is disclosed in JP-A-7-126996. The use of an agent is liable to adversely affect paper quality such as paper size, and is not a satisfactory method. JP-A-58-220889 discloses a hydrophobic monomer such as (meth) acrylamide and styrene which are nonionic hydrophilic monomers as a type which does not adversely affect the ion balance of papermaking additives and the like. Although a method of using a copolymer with a body as a pitch adhesion inhibitor for papermaking is disclosed, nonionic ones are difficult to fix to pulp fibers, causing foaming in papermaking systems, and other causes of trouble There is a problem that it is easy to become. Further, JP-A-53-41507 discloses a water-soluble linear cation copolymerized with a homopolymer comprising a polymer unit represented by the following [Chemical Formula 1] or another ethylenically unsaturated monomer. Although a method using a composition for preventing pitch adhesion containing a polymer has been disclosed, the effect of suppressing the pitch failure was not satisfactory.
[0004]
[Chemical 1]

Wherein A is an alkylene group having 2 or 3 carbon atoms, R is H or CH _Three , R ₁ Is a hydroxyethyl group or a hydroxypropyl group, R ₂ And R _Three Represents an alkyl group having 1 to 4 carbon atoms, and X represents an anion. )
[0005]
In recent years, from the viewpoint of forest protection and cost reduction, the production of paper using blended mechanical pulp with good raw material efficiency in raw pulp has increased, while on the other hand, the neutralization of papermaking With the progress, neutral sizing agents such as ketene dimer sizing agents, substituted cyclic dicarboxylic acid anhydride sizing agents, and rosin sizing agents for neutral papermaking have come to be used relatively widely. In a papermaking system that uses pulp raw material containing pulp and performs sizing with a neutral sizing agent, there is a strong demand for a method for producing a paper that suppresses pitch disturbance and is excellent in the size of the obtained paper.
A first object of the present invention is to provide a mechanical pulp-containing paper capable of suppressing pitch disturbance and a method for producing the same.
The second object of the present invention is to provide a mechanical pulp-containing paper having excellent size properties and a method for producing the same.
The third object of the present invention is to provide a mechanical pulp-containing paper that can improve the yield of the neutral sizing agent and a method for producing the same.
[0006]
[Means for solving problems]
As a result of intensive studies to achieve the above object, the present inventors have (1) mechanical pulp sized with a neutral sizing agent using paper pulp containing at least 5% by weight of mechanical pulp on a dry weight basis. In the containing paper, a vinyl copolymer having a combination of structural units corresponding to each of the following monomers (A) 50 to 95% by weight and (B) 5 to 50% by weight and having a quaternary ammonium salt: The present invention provides a mechanical pulp-containing paper containing a cationic polymer as a polymer as an additive in an amount of 0.03 to 1% by weight based on the dry weight of the mechanical pulp.
(A) At least one hydrophobic monomer selected from the group consisting of styrene monomers and alkyl (meth) acrylates
(B) A monomer having a tertiary amino group composed of dialkylaminoalkyl (meth) acrylamide and dialkylaminoalkyl (meth) acrylate and a monomer having a quaternary ammonium salt composed of each quaternized product. At least one cationic monomer
The present invention also relates to (2) the mechanical pulp-containing paper of (1), wherein a vinyl monomer other than the components (A) and (B) is used as a part of the component (B), 3) The above (1) or (1), wherein the neutral sizing agent is at least one selected from the group consisting of a ketene dimer sizing agent, a substituted cyclic dicarboxylic acid anhydride sizing agent, and a rosin sizing agent for neutral papermaking. 2) Mechanical pulp-containing paper, (4) Papermaking pulp containing paper pulp containing at least 5% by weight of mechanical pulp on a dry weight basis and sizing using a neutral sizing agent at pH 6-9. In the method for producing mechanical pulp-containing paper, a vinyl copolymer obtained from a monomer containing 50 to 95% by weight of the following (A) and 5 to 50% by weight of the following (B), the following component (B) As a single monomer having a tertiary amino group Is used in the papermaking step, an additive containing a cationic polymer having a quaternary ammonium salt that may be quaternized in at least one of the polymerization process and post-polymerization of the vinyl copolymer, And the manufacturing method of the mechanical pulp containing paper which uses this cationic polymer 0.03-1 weight% with respect to the dry weight of the said mechanical pulp,
(A) At least one hydrophobic monomer selected from the group consisting of styrene monomers and alkyl (meth) acrylates
(B) A monomer having a tertiary amino group composed of dialkylaminoalkyl (meth) acrylamide and dialkylaminoalkyl (meth) acrylate and a monomer having a quaternary ammonium salt composed of each quaternized product. At least one cationic monomer
(5) A method for producing a mechanical pulp-containing paper as described in (4) above, wherein a vinyl monomer other than the components (A) and (B) is used as part of the component (B). is there.
[0007]
Next, the present invention will be described in detail.
In the present invention, mechanical pulp is pulp produced by mechanically fiberizing wood, and high-yield pulp such as groundwood pulp, refiner groundwood pulp, pressure groundwood pulp, thermomechanical pulp, This refers to deinked pulp and the like obtained by deinking and deinking paper made from yield pulp.
[0008]
The neutral sizing agent is a sizing agent used in the papermaking system in the neutral range, such as a ketene dimer sizing agent, a substituted cyclic dicarboxylic acid anhydride sizing agent, and a rosin sizing agent for neutral papermaking. These can be used singly or as a mixture of at least two, and known general commercial products can be used. The addition ratio of the ketene dimer sizing agent and / or the substituted cyclic dicarboxylic acid anhydride sizing agent to the pulp slurry is preferably 0.01 to 1%, more preferably 0.02 to 0.5% with respect to the dried pulp. It is. If the addition rate of the ketene dimer sizing agent and / or the substituted cyclic dicarboxylic acid anhydride sizing agent is less than 0.01%, the size effect may not be sufficient. If it exceeds 1%, the cost increases and the papermaking system May cause dirt.
[0009]
As the rosin-based sizing agent for neutral papermaking, a rosin-type rosin described in Japanese Patent Application No. 9-61762, for example, can be used that has been modified to make it hydrophobic. The addition ratio of the rosin sizing agent for neutral papermaking to the pulp slurry is preferably 0.01 to 2%, more preferably 0.05 to 1% with respect to the dried pulp. If the addition ratio is less than 0.01%, the size effect may not be sufficient. If the addition ratio is more than 2%, the cost may increase and papermaking stains may be caused. Among the ketene dimer sizing agent, the substituted cyclic dicarboxylic acid anhydride sizing agent and the rosin sizing agent for neutral papermaking, the use of the ketene dimer sizing agent contains the cationic polymer used in the present invention. When used in combination with an additive, it is more preferable in terms of the effect of suppressing pitch disturbance and the effect of improving size.
[0010]
The cationic polymer used in the present invention has a bond of constituent units corresponding to each monomer of the component (A) 50 to 95% by weight and the component (B) 5 to 50% by weight, and quaternary ammonium. A cation that is a vinyl copolymer having a salt, but is a vinyl copolymer obtained from a monomer composition containing 50 to 95% by weight of the component (A) and 5 to 50% by weight of the component (B). In the case where a monomer having a tertiary amino group is used as the component (B), a quaternizing agent is used at least one of the polymerization process and post-polymerization of the cationic copolymer. May be quaternized. Even when a monomer having a tertiary amino group is used as the component (B), when the quaternized monomer is used, at least one of the polymerization process and post-polymerization of the cationic copolymer In some cases, it is not necessary to use a quaternizing agent.
Examples of the styrene monomer of the component (A) include styrene, vinyl toluene, α-methyl styrene, divinyl benzene, and the like, and these can be used alone or in at least two kinds.
In addition, as the above-mentioned component (A), alkyl (meth) acrylate (indicating at least one of alkyl acrylate and alkyl methacrylate, hereinafter referred to as a compound to which (meth) is added) applies methyl (meth). Lower alkyl groups such as acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, higher alkyl groups or cyclo The monomer which has an alkyl group is mentioned, These can be used 1 type or at least 2 types.
[0011]
Examples of the dialkylaminoalkyl (meth) acrylamide as the monomer having a tertiary amino group as the component (B) include N, N-dimethylaminopropyl (meth) acrylamide. Examples of the dialkylaminoalkyl (meth) acrylate include N, N-dimethylaminoethyl (meth) acrylate.
As the monomer having the quaternary ammonium salt of the component (B), the above-mentioned monomer having a tertiary amino group is alkyl halide, benzyl halide, alkyl tosylate, alkyl mesylate, dialkyl carbonate, dimethyl sulfate. , A method of making a quaternary ammonium salt by reaction with a quaternizing agent such as epihalohydrin, or a method of making a bis quaternary ammonium salt by reaction with a quaternizing agent such as 3-chloro-2-hydroxypropyltrimethylammonium chloride Etc.
These monomers can be used alone or in at least two kinds.
In order to obtain the cationic polymer of the present invention, as described above, a monomer having a tertiary amino group of dialkylaminoalkyl (meth) acrylamide and / or dialkylaminoalkyl (meth) acrylate as the component (B) is used. A method of copolymerizing with a hydrophobic monomer of the component (A) after making a quaternized product, a monomer having a tertiary amino group of the component (B) and a hydrophobic single amount of the component (A) Either a method of performing a quaternization reaction in the middle of copolymerization or a method of performing a quaternization reaction after the copolymerization may be used, but the above-mentioned component (A) for all monomers constituting the cationic polymer may be used. The proportion of the hydrophobic monomer is 50 to 95% by weight, preferably 55 to 90% by weight. When the proportion of the hydrophobic monomer is less than 50% by weight or more than 95% by weight, it is difficult to obtain the effect of suppressing the pitch hindrance and it is difficult to improve the paper size. The proportion of the monomer (B) having a tertiary amino group and / or its quaternized monomer is 5 to 50% by weight, preferably 10 to 45% by weight. When these ratios are less than 5% by weight or more than 50% by weight, it is difficult to obtain the effect of suppressing the pitch disturbance and it is difficult to improve the paper size. In addition, a copolymer having a dialkylaminoalkyl (meth) acrylamide quaternized product in the copolymerized unit is more preferable than a copolymer having a dialkylaminoalkyl (meth) acrylate quaternized product in the copolymerized unit. Good hydrolyzability.
[0012]
In the present invention, in addition to the above-mentioned monomer, if desired, a method of replacing a part of dialkylaminoalkyl (meth) acrylamide quaternized product and / or dialkylaminoalkyl (meth) acrylate quaternized product (meth) Acrylamide, (meth) acrylonitrile, olefin, vinyl ether, allyl ester, vinyl ketone, vinylsulfonamide, N-vinyl-2-pyrrolidone, 2-hydroxyethyl (meth) acrylate, diacetone acrylamide, N-alkyl (meth) acrylamide , Vinyl monomers such as methylenebisacrylamide, allylamine, diallylamine, vinylpyridine, vinylformamide, vinylacetamide, and vinylamine derivatives can be used in combination. These can be used alone or in combination of at least two.
[0013]
As a polymerization method of the copolymer, the above monomer is polymerized in the presence of a radical polymerization initiator using a solution polymerization method, a bulk polymerization method, an emulsion polymerization method, a dispersion polymerization method, or the like. A cationic polymer aqueous solution can be obtained by distilling off the solvent as necessary and adjusting the concentration to a predetermined solid content concentration. Although this may be used as an additive as it is, it may be an additive obtained by adding other additives.
The cationic polymer is added to the pulp raw material at a ratio of 0.03 to 1% by weight with respect to the dry weight of the mechanical pulp blended in the pulp raw material. If the addition rate of the cationic polymer is less than 0.03% with respect to the dry weight of the mechanical pulp, the effect of suppressing pitch disturbance and the imparting of size to the paper are not sufficient, and if it exceeds 1%, the cost increases. .
[0014]
There are no restrictions on the location of the additive containing the cationic polymer used in the present invention and the neutral sizing agent in the papermaking process, but it is desirable that they are sufficiently dispersed in the pulp slurry. There is no limitation on the order of addition, and the additive may be added first, then in the order of neutral sizing agent, or vice versa, or these may be added simultaneously, or a mixture of these may be added. good. In addition, additives such as a filler, a dry paper strength enhancer, a yield improver, and a freeness improver may be used as necessary to exhibit the required physical properties of each paper type.
The papermaking pH in the present invention is in the range of 6-9. When the pH is lower than 6, the sizing effect of the ketene dimer sizing agent and the substituted cyclic dicarboxylic acid anhydride sizing agent is lowered. Even when the pH is higher than 9, the sizing effect of the neutral sizing agent is lowered, and further, there are problems such as yellowing of mechanical pulp, which is not practical.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
1) styrene, 2-ethylhexyl (meth) acrylate, methyl methacrylate as a hydrophobic monomer, 2) N, N-dimethylaminopropyl (meth) acrylamide, N, N as a monomer having a tertiary amino group -Dimethylaminoethyl (meth) acrylate is used, and at least one of (1) and at least one of (2), preferably (1) styrene and (2) N, N-dimethylaminopropylacrylamide are used. A monomer aqueous solution is copolymerized, and an aqueous cationic polymer solution is prepared by quaternizing the copolymer with epihalohydrin. With respect to these, the copolymerization ratio was set to 15 to 50% by weight as a monomer obtained by quaternizing the monomer (a) (1) with 50 to 85% by weight and the monomer (2) with epihalohydrin. A cationic polymer; and (b) at least one of the above-mentioned (1), preferably 55 to 60% by weight of a monomer containing styrene, and (2) a monomer having a quaternary ammonium salt. A cationic polymer obtained by copolymerizing 40 to 45% by weight of N, N-dimethylaminopropyl methacrylamide quaternized with an alkyl halide, and (c) a monomer containing at least one of the above (1), preferably styrene. 55 to 60% by weight of monomer, 39 to 41% by weight of N, N-dimethylaminopropyl methacrylamide quaternized with at least one of (2), preferably alkyl halide, (meth) acrylamide Preparing an additive comprising a cationic polymer aqueous solution containing 4% by copolymerizing not have a cationic polymer respectively.
Using raw material pulp with a mechanical pulp content of 10 to 90% by weight on a dry weight basis, the amount of ketene dimer sizing agent added is 0.1 to 0.2% by weight (vs dry pulp), and the above additives are added. Add 0.02-0.08% by weight (based on mechanical pulp) as the cationic polymer content of the above (a) to (c) and make paper. Further, in place of the ketene dimer sizing agent, alkenyl succinic anhydride sizing agent is used in an amount of 0.1 to 0.2% by weight (vs. dry pulp), and the content of mechanical pulp is 8 to 12% by weight. The additive is added in an amount of 0.5 to 0.9% by weight (based on mechanical pulp) as the cationic polymer component (a) to (c), and paper is made. Further, instead of alkenyl succinic anhydride sizing agent, 0.2 to 0.4% by weight (based on dry pulp) of rosin sizing agent for neutral papermaking is used, and the content of mechanical pulp is 20 to 40% by weight. Then, 0.25 to 0.45% by weight (based on mechanical pulp) is added as the cationic polymer component (a) to (c) above, and paper is made.
In this way, the sizing agent is fixed in a large amount, and there is little dirt such as rolls, and the obtained paper has a good sizing degree. The reason is that it contains the cationic polymers (a) to (c) above. It is understood that the use of such additives makes it possible for the pitch and neutral sizing agent associated with the mechanical pulp to be easily retained in the paper stock, and therefore to be difficult to adhere to papermaking tools such as felts and rolls. This is because the cationic polymer of the above (a) to (c) balances the hydrophobic part composed of the structural unit corresponding to the hydrophobic monomer and the hydrophilic part composed of the structural unit corresponding to the cationic monomer. It has a good affinity between the hydrophobic part and the hydrophobic part of pitch and neutral sizing agent, and the hydrophilic part is considered to have good affinity with water. It is not something that can be done.
[0016]
【Example】
EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to these examples. In the following examples and comparative examples, “%” means solid weight% unless otherwise specified.
[0017]
Production Example 1 of Cationic Polymer Aqueous Solution (Additive) for Examples
In a 1 liter four-necked flask equipped with a stirrer, a thermometer, and a condenser tube, 72.9 g of styrene, 9.2 g of 2-ethylhexyl acrylate, N-ethyl-N, N-dimethyl-3- (methacryloylaminopropyl) ammonium 57.6 g of bromide, 7.1 g of 50% acrylamide aqueous solution, 150 g of isopropyl alcohol and 2 g of azobisisobutyronitrile were added and reacted at 80 ° C. for 5 hours in a nitrogen stream. Next, 422 g of water was added, and the mixture was well stirred and dispersed in water, followed by cooling to obtain 700 g of an aqueous cationic polymer liquid A. Its solid content was 20%. The weight percentage of each monomer with respect to the total monomers was 50.9% styrene, 6.4% 2-ethylhexyl acrylate, N-ethyl-N, N-dimethyl-3- (methacryloylaminopropyl) ammonium bromide. 2% and acrylamide 2.5%, and the total of the hydrophobic monomers combining styrene and 2-ethylhexyl acrylate is 57.3%. The weight composition of the monomers used is shown in Table 1.
[0018]
Production Example 2 of Cationic Polymer Aqueous Solution (Additive) for Examples 2
Into a 1 liter four-necked flask equipped with a stirrer, thermometer, and condenser, 83.3 g of styrene, 31.2 g of N, N-dimethylaminopropylacrylamide, 117 g of benzene, and 2 g of azobisisobutyronitrile are added. The reaction was performed at 80 ° C. for 5 hours in an air stream. Next, 423 g of a 3% acetic acid solution was added and heated to 97 ° C. to distill off benzene. After distilling off, the distilled water was added, 18.5 g of epichlorohydrin was added, and quaternization was performed at 80 ° C. for 3 hours, followed by cooling to obtain 670 g of cationic polymer aqueous solution B. Its solid content was 20%. The weight composition of the monomers used is shown in Table 1.
[0019]
Production Examples 3-6 of Cationic Polymer Aqueous Solution (Additive) for Examples
Cationic polymer aqueous liquids C, D, E, and F were produced in the same manner as in Production Example 2 of the cationic copolymer for Examples except that the type and weight composition of the monomers shown in Table 1 were changed. The solid content concentration of the copolymer was adjusted to 20%. The weight composition of the monomers used is shown in Table 1.
[0020]
Production Example 1 of Cationic Polymer Aqueous Solution (Additive) for Comparative Example
According to Example 1 of JP-A-53-41507, a homopolymer of N, N-dimethyl-N- (β-hydroxyethyl) -N- (β-methacryloxyethyl) ammonium acetate was produced as follows. did. 19.3 parts glacial acetic acid, 60.5 parts deionized water and 28.6 parts 0.15% FeSO _Four ・ H ₂ An aqueous O solution was placed in a pressure kettle. Oxygen was removed from the kettle contents with nitrogen, heated to 60 ° C., an aqueous solution prepared by dissolving 47.8 parts of dimethylaminoethyl methacrylate and 9.8 parts of ammonium peroxosulfate in 116.2 parts of deionized water, and sodium sulfite 9.8 An aqueous solution in which 11 parts were dissolved in 116.2 parts deionized water was added after 3 hours. The mixture was kept at 60 ° C. for another 30 minutes, then lowered to 40 ° C., and 140.7 parts of ethylene oxide was gradually added at that temperature to obtain an aqueous cationic polymer liquid G. The weight composition of the monomers used is shown in Table 1.
[0021]
Production Examples 2 and 3 of an aqueous cationic polymer liquid (additive) for Comparative Example
Except changing to the kind and weight composition of the monomer shown in Table 1, the polymer of the cationic polymer aqueous liquid H and I was obtained by the procedure of the manufacture example 1 of the cationic polymer for comparative examples.
[0022]
Production Example 4 of Cationic Polymer Aqueous Solution (Additive) for Comparative Example
A cationic polymer aqueous solution J for Comparative Example was produced in the same manner as in Production Example 2 of the cationic copolymer for Examples except that the type and weight composition of the monomers shown in Table 1 were changed. The solid content concentration of the copolymer was adjusted to 20%.
[0023]
[Table 1]

[0024]
Example 1
Prepare a 2.5% pulp slurry (Canadian Standard Freeness 380 ml) of ground pulp, thermomechanical pulp, bleached hardwood kraft pulp mixed at a ratio of 5/5/90 on a dry weight basis (mechanical pulp 10%), Light calcium carbonate (Tama Pearl 121S, manufactured by Okutama Kogyo Co., Ltd.) was added to this with 15% dry pulp, and after stirring for 2 minutes, the sulfuric acid band was 0.5% dry pulp and amphoteric starch (Cato3210, manufactured by NSC Japan). ) With respect to dry pulp 0.6%, and alkyl ketene dimer sizing agent (AS263, manufactured by Nippon PMC Co., Ltd.) with respect to dry pulp 0.1% were added in this order with stirring. The interval between additions was 1 minute. Thereafter, 0.005% dry pulp (0.05% mechanical pulp) was added as the cationic polymer aqueous solution A to the cationic polymer, and the mixture was stirred for 1 minute. Furthermore, the obtained paper stock was diluted to 0.25% with pH 8 dilution water, and a yield improver (NR12MLS, manufactured by Hymorlock Co., Ltd.) was added to 0.02% of dry pulp and stirred for 30 seconds. The papermaking pH here was 7.8. A wet paper was made from the resulting stock using a Noble and Wood handmade machine. The papermaking temperature was 45 ° C. The wet paper was pressed and then dried with a drum dryer at 100 ° C. for 80 seconds to obtain the desired handmade paper. Basis weight is 70 g / m ² Adjusted.
[0025]
With respect to the prepared handmade paper, according to JIS P-8122, the degree of squeecht size was measured immediately after papermaking and 1 day after humidity conditioning. The humidity control conditions were 65% RH and 20 ° C. Further, the amount of alkyl ketene dimer in the paper was measured by a pyrolysis gas chromatograph. The results are shown in Table 2.
[0026]
In addition, the following test simulating the phenomenon that the press roll of a paper machine is soiled was conducted to examine the effect of suppressing the pitch failure.
That is, AS263 is doubled to 0.2% in the hand-drawing experiment. Further, a paper stock was prepared in the same manner except that the dilution concentration with dilution water was 0.7%. The obtained stock is supplied to a roll stain tester (a test device for testing stains on a papermaking apparatus, and a schematic explanatory diagram is shown in FIG. 1), and the degree of stain on the press roll after 2 hours and 5 hours. I investigated. The dirt was evaluated visually, and was indicated by a graded evaluation using an index where “10” was the most marked dirt on the press roll and “0” was no dirt. The results are shown in Table 2.
The reason why the addition rate of AS263 is doubled is to make the difference in effect stand out, and there is a correlation with the case where papermaking in these normal addition amounts is continued for a long time.
[0027]
In FIG. 1, the paper material is sequentially supplied from the paper material inlet 1 to the wire device 2, and after gravity dewatering, it is pressed by the first roll 3 and the main roll 4, and then the main roll 4 and the second roll 5. 1 shows an apparatus for obtaining a wet paper 6 that has been pressed and dehydrated, and its specific structure is as follows.
Main roll: 25cm in diameter, 40cm in width
First roll: about 14.5 cm in diameter and about 40 cm in width
Second roll: about 10 cm in diameter and about 40 cm in width
Wire: about 35cm wide
In this apparatus, the pressure of the first roll and the second roll against the main roll depends on the weight of each roll, and the moisture content of the wet paper after passing through the second roll is 60%. The test conditions were a paper making speed of 1.5 m / min, a paper material temperature of 45 ° C., a roll temperature of 34 to 36 ° C., and a paper making width of 15 cm. The stain on the second roll was examined visually.
[0028]
Example 2
Using 2.5% pulp slurry (Canadian Standard Freeness 280ml) of ground pulp, thermomechanical pulp, bleached hardwood kraft pulp mixed at a ratio of 15/15/70 on a dry weight basis (mechanical pulp 30%), A hand-made paper was prepared in the same manner as in Example 1 except that the addition rate of the cationic polymer aqueous liquid A was 0.02% to dry pulp (0.067% to mechanical pulp) as the cationic polymer. Was measured to determine the fixing amount of the sizing agent. Further, a roll soil test was conducted in the same manner as in Example 1. The results are shown in Table 2.
[0029]
Examples 3-7
A handmade paper was prepared in the same manner as in Example 2 except that the cationic polymer aqueous liquids B, C, D, E, and F were used in place of the cationic polymer aqueous liquid A, respectively. The sizing degree was measured to determine the fixing amount of the sizing agent. In addition, a roll soil test was performed in the same manner as in Example 2. The results are shown in Table 2.
[0030]
Example 8
Of pulp mixed with groundwood pulp, thermomechanical pulp, paper deinked pulp made from high-yield pulp, bleached hardwood kraft pulp at a ratio of 30/30/30/10 (mechanical pulp 90%) on a dry weight basis Using 2.5% pulp slurry (Canadian Standard Freeness 190 ml), AS263 was 0.2% to dry pulp, and the addition rate of cationic polymer aqueous liquid A as the cationic polymer was 0.03% to dry pulp. A hand-made paper was prepared in the same manner as in Example 1 except that it was (compared to mechanical pulp 0.033%), and the sizing degree was measured in the same manner as in Example 1 to determine the fixing amount of the sizing agent. In addition, a roll soil test was conducted in the same manner as in Example 1. The results are shown in Table 2.
[0031]
Comparative Examples 1-4
A handmade paper was prepared in the same manner as in Example 2 except that the cationic polymer aqueous liquids G, H, I and J were used in place of the cationic polymer aqueous liquid A, respectively. Was measured to determine the fixing amount of the sizing agent. In addition, a roll soil test was performed in the same manner as in Example 2. The results are shown in Table 2.
[0032]
Comparative Example 5
A handmade paper was prepared in the same manner as in Example 2 except that the addition ratio of the cationic polymer aqueous liquid A as the cationic polymer content was 0.005% to dry pulp (compared to mechanical pulp 0.017%). The sizing degree was measured in the same manner as in Example 2 to determine the fixing amount of the sizing agent. In addition, a roll soil test was performed in the same manner as in Example 2. The results are shown in Table 2.
[0033]
Comparative Example 6
A handmade paper was prepared in the same manner as in Example 8 except that the addition ratio of the cationic polymer aqueous liquid A as the cationic polymer content was 0.02% to dry pulp (0.022% to mechanical pulp). The sizing degree was measured in the same manner as in Example 8 to determine the fixing amount of the sizing agent. In addition, a roll soil test was performed in the same manner as in Example 8. The results are shown in Table 2. In addition, although the evaluation of the roll soil test was “10”, since the degree thereof was inferior to that of Comparative Example 1, it was set to “10 (or higher)”.
[0034]
[Table 2]

[0035]
Example 10
Instead of the alkyl ketene dimer sizing agent, an alkenyl succinic anhydride sizing agent (AS290, manufactured by Nippon PMC Co., Ltd.) is used with 0.1% dry pulp, and the addition rate of the cationic polymer aqueous liquid A is compared with the drying rate. A handmade paper was prepared in the same manner as in Example 2 except that the pulp was 0.07% (vs. mechanical pulp: 0.23%), and the sizing degree was measured in the same manner as in Example 2. The papermaking pH was 7.8. The amount of alkenyl succinic anhydride in the obtained paper was measured by pyrolysis gas chromatography, and the fixing amount of the sizing agent was determined in the same manner as in the above example using a ketene dimer sizing agent. Moreover, it replaced with the alkyl ketene dimer type | system | group sizing agent, and the roll dirt test was done like the said Example 1 except having used 0.2% of said AS290 with respect to dry pulp. The evaluation method was performed according to Example 1. The results are shown in Table 3.
[0036]
Examples 11-15
A handmade paper was prepared in the same manner as in Example 10 except that the cationic polymer aqueous liquids B, C, D, E, and F were used instead of the cationic polymer aqueous liquid A, respectively. The sizing degree was measured to determine the fixing amount of the sizing agent. Further, a roll soil test was conducted in the same manner as in Example 10. The results are shown in Table 3.
[0037]
Comparative Examples 7-10
A handmade paper was prepared in the same manner as in Example 10 except that the cationic polymer aqueous liquids G, H, I, and J were used in place of the cationic polymer aqueous liquid A, respectively. Was measured to determine the fixing amount of the sizing agent. Further, a roll soil test was conducted in the same manner as in Example 10. The results are shown in Table 3.
[0038]
[Table 3]

[0039]
Example 16
The addition rate of aluminum sulfate was 1.5%, and rosin sizing agent for neutral papermaking (CC167, manufactured by Nippon PMC Co., Ltd.) was used instead of alkyl ketene dimer sizing agent. A hand-made paper was prepared in the same manner as in Example 2 except that the addition ratio of the water-soluble polymer aqueous solution A was 0.1% to dry pulp (0.33% to mechanical pulp) as the cationic polymer. The degree of sizing was measured in the same manner as in 2. The papermaking pH was 7.6.
Hand paper is loosened under acidic conditions, extracted with ether, the amount of rosin component in the organic phase is measured by gel permeation chromatography, and the size is determined in the same manner as in Example 1 above using a ketene dimer sizing agent. The fixing amount of the agent was determined. Moreover, it replaced with the alkyl ketene dimer type | system | group sizing agent, and the roll soil test was done like the said Example 1 except having used said CC167 0.5% of dry pulp. The evaluation method was performed according to Example 1. The results are shown in Table 4.
[0040]
Examples 17-21
A handmade paper was prepared in the same manner as in Example 16 except that the cationic polymer aqueous liquids B, C, D, E, and F were used in place of the cationic polymer aqueous liquid A, respectively. The sizing degree was measured to determine the fixing amount of the sizing agent. Further, a roll soil test was conducted in the same manner as in Example 16. The results are shown in Table 4.
[0041]
Comparative Examples 11-14
A handmade paper was prepared in the same manner as in Example 16 except that the cationic polymer aqueous liquids G, H, I, and J were used in place of the cationic polymer aqueous liquid A, respectively. Was measured to determine the fixing amount of the sizing agent. Further, a roll soil test was conducted in the same manner as in Example 16. The results are shown in Table 4.
[0042]
[Table 4]

[0043]
From the above results, it can be seen that in the papermaking system using the raw material pulp containing mechanical pulp, both the pitch suppression effect and the size of the obtained paper are superior to those of the comparative example. That is, when using a raw material blended with mechanical pulp and sizing with a neutral sizing agent, by making a paper using the cationic polymer according to the present invention, it is possible to suppress pitch disturbance and improve the size of the paper. Can be planned.
As can be seen from the comparison of the data of Example 1 and Comparative Example 5, Example 2 and Comparative Example 6, when the proportion of mechanical pulp to be blended is high, the addition rate of the cationic polymer according to the present invention is also high accordingly. There is a need to. Although its action mechanism is not clear, it is considered that the cationic polymer according to the present invention has an action of preventing aggregation of pitch components in mechanical pulp. In terms of the sizing agent fixing amount, the example is higher than the comparative example. This is because the increase in the yield of the sizing agent reduces the sizing agent and its hydrolyzate that are likely to contribute to the pitch hindrance, and also improves the sizing degree of the paper. It is thought that it is because. The cationic polymer according to the present invention is different from the cationic polymer of the comparative example in that it has a certain amount or more of a hydrophobic portion, but the certain amount or more of the hydrophobic portion contains a mechanical pulp. It can be said that it works effectively under the condition that a neutral sizing agent is used in the system. That is, the cationic polymer according to the present invention in which a certain amount or more of the hydrophobic portion is introduced can suppress the level of pitch hindrance that could not be achieved in the past, and can improve the sizing degree of the paper.
[0044]
【The invention's effect】
According to the present invention, it is possible to suppress a pitch failure when sizing with a neutral sizing agent using a pulp raw material blended with mechanical pulp, improve the yield of the neutral sizing agent, and mechanical pulp having excellent sizing properties. It is possible to provide a containing paper and a method for producing the same.
[Brief description of the drawings]
FIG. 1 is a test apparatus for testing dirt on a roll of a papermaking apparatus.

Claims (5)

In mechanical pulp-containing paper sized with a neutral sizing agent using pulp for papermaking containing at least 5% by weight of mechanical pulp on a dry weight basis, (A) 50 to 95% by weight and (B) 5 to 50% below % Of the unit weight of the mechanical pulp with respect to the dry weight of the mechanical pulp, using as an additive a cationic polymer which is a vinyl copolymer having a combination of structural units corresponding to each monomer and having a quaternary ammonium salt. Mechanical pulp-containing paper containing 03 to 1% by weight.
(A) At least one hydrophobic monomer selected from the group consisting of a styrene monomer and an alkyl (meth) acrylate (B) a dialkylaminoalkyl (meth) acrylamide and a dialkylaminoalkyl (meth) acrylate At least one cationic monomer selected from the group of monomers having a tertiary amino group and monomers having a quaternary ammonium salt comprising each quaternized product The mechanical pulp-containing paper according to claim 1, wherein a vinyl monomer other than the components (A) and (B) is used as a part of the component (B). The mechanical pulp according to claim 1 or 2, wherein the neutral sizing agent is at least one selected from the group consisting of a ketene dimer sizing agent, a substituted cyclic dicarboxylic anhydride sizing agent, and a rosin sizing agent for neutral papermaking. Contains paper. In a method for producing a mechanical pulp-containing paper having a papermaking process in which a pulp for papermaking containing at least 5% by weight of mechanical pulp on a dry weight basis is used as a raw material and sizing using a neutral sizing agent at pH 6 to 9, the following (A ) A vinyl copolymer obtained from a monomer containing 50 to 95% by weight and the following (B) 5 to 50% by weight, wherein a monomer having a tertiary amino group is used as the following (B) component In the above paper making process, an additive containing a cationic polymer having a quaternary ammonium salt that may be quaternized in at least one of the polymerization process and post-polymerization of the vinyl copolymer, and A method for producing a mechanical pulp-containing paper, wherein the cationic polymer is used in an amount of 0.03 to 1% by weight based on the dry weight of the mechanical pulp.
(A) At least one hydrophobic monomer selected from the group consisting of a styrene monomer and an alkyl (meth) acrylate (B) a dialkylaminoalkyl (meth) acrylamide and a dialkylaminoalkyl (meth) acrylate At least one cationic monomer selected from the group of monomers having a tertiary amino group and monomers having a quaternary ammonium salt comprising each quaternized product The method for producing a mechanical pulp-containing paper according to claim 4, wherein a vinyl monomer other than the components (A) and (B) is used as a part of the component (B).

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