JP3946530B2 - Oxyalkylene group-containing vinyl ester polymer and method for producing saponified product thereof - Google Patents

Description

（但し、Ｒは水素又はメチル基、Ｒ _１ ，Ｒ _２ は水素又はアルキル基、Ｒ _３ は水素、アルキル基、アルキルエステル基、アルキルアミド基、スルホン酸基、フェニル基または置換フェニル基のいずれか、ｎは正の整数を示す。）
【０００５】
【発明の実施の形態】
以下、本発明を詳細に説明する。
【０００６】
本発明に用いるオキシアルキレン基含有モノマーとは、下記の一般式（１）で表されるオキシアルキレン基を含有するものである。
【化１】

（但し、Ｒ_１，Ｒ_２は水素又はアルキル基、Ｒ_３は水素、アルキル基、アルキルエステル基、アルキルアミド基、スルホン酸基、フェニル基または置換フェニル基のいずれか、ｎは正の整数を示す。）
【０００７】
上記の一般式（１）において、ｎの数、即ちオキシアルキレン基の平均鎖長は２〜３００程度で、重合時の作業性等を考慮すれば、５〜６０程度が好ましい。かかるオキシアルキレン基として具体的には、ポリオキシエチレン基、ポリオキシプロピレン基、ポリオキシブチレン基等が挙げられる。
【０００８】
オキシアルキレン基を有するモノマーとしては、下記の一般式で示される（メタ）アリルエーテル型のものが挙げられ、具体的にはポリオキシエチレン（メタ）アリルエーテル、ポリオキシプロピレン（メタ）アリルエーテル等が挙げられる。
【化２】

（但し、Ｒは水素又はメチル基、Ｒ _１ ，Ｒ _２ ，Ｒ _３ ，ｎは前記と同様。）
【００１２】
オキシアルキレン基含有モノマーと（共）重合するビニルエステルモノマーとしては、ギ酸ビニル、酢酸ビニル、トリフルオロ酢酸ビニル、プロピオン酸ビニル、酪酸ビニル、カプリン酸ビニル、ラウリル酸ビニル、バーサティック酸ビニル、パルミチン酸ビニル、ステアリン酸ビニル、ピバリン酸ビニル等を挙げることができるが、工業的には酢酸ビニルが好適に用いられる。
【００１３】
本発明においては、本発明の目的を阻害しない範囲で、前述した如きオキシアルキレン基含有モノマーやビニルエステルモノマー以外に、他の一般のモノマーを５０モル％以下共存させても良い。これらのモノマーを以下に例示する。
［エチレン性不飽和カルボン酸及びそのアルキルエステル等］
クロトン酸メチル、クロトン酸エチル、イタコン酸メチル、イタコン酸エチル、ソルビン酸メチル、ソルビン酸エチル、マレイン酸モノアルキルエステル、マレイン酸ジアルキルエステル、オレイン酸アルキルエステル、（メタ）アクリル酸メチル、（メタ）アクリル酸エチル、（メタ）アクリル酸プロピル、（メタ）アクリル酸ブチル、（メタ）アクリル酸ペンチル、（メタ）アクリル酸ヘプチル、（メタ）アクリル酸オクチル、（メタ）アクリル酸デシル、（メタ）アクリル酸ヘキサデシル、（メタ）アクリル酸オクタデシル等が挙げられる。
【００１４】
［飽和カルボン酸のアリルエステル］
ステアリン酸アリル、ラウリン酸アリル、ヤシ油脂肪酸アリル、オクチル酸アリル、酪酸アリル等。
［α−オレフィン］
エチレン、プロピレン、α−ヘキセン、α−オクテン、α−デセン、α−ドデセン、α−ヘキサデセン、α−オクタデセン等。
［エチレン性不飽和カルボン酸］
（メタ）アクリル酸、クロトン酸、（無水）マレイン酸、フマル酸、イタコン酸ならびにこれらのアルカリ金属塩、アンモニウム塩等。
【００１５】
［アルキルビニルエーテル］
プロピルビニルエーテル、ブチルビニルエーテル、ヘキシルビニルエーテル、オクチルビニルエーテル、デシルビニルエーテル、ドデシルビニルエーテル、テトラデシルビニルエーテル、ヘキサデシルビニルエーテル、オクタデシルビニルエーテル等。
【００１６】
［アルキルアリルエーテル］
プロピルアリルエーテル、ブチルアリルエーテル、ヘキシルアリルエーテル、オクチルアリルエーテル、デシルアリルエーテル、ドデシルアリルエーテル、テトラデシルアリルエーテル、ヘキサデシルアリルエーテル、オクタデシルアリルエーテル等。
その他、（メタ）アクリルアミド、（メタ）アクリロニトリル、（メタ）アリルスルホン酸塩、エチレン性不飽和スルホン酸塩、スチレン、塩化ビニルやアミノ基、アンモニウム基、カルボキシル基、スルホン酸基等を含有するチオール系の連鎖移動剤などの使用も可能である。
【００１７】
本発明の最大の特徴は、上記の如きオキシアルキレン基含有モノマーとビニルエステルモノマーを重合するにあたり、全仕込量のオキシアルキレン基含有モノマーと全仕込量の５０〜９９重量％のビニルエステルモノマーを重合系に仕込んで重合を開始し、仕込量に対するビニルエステルモノマーの重合率が５０〜９９％の時点において残りのビニルエステルモノマーを仕込むもので、かかる方法について具体的に説明する。
【００１８】
まず、重合系（通常は重合缶）に、全仕込量のオキシアルキレン基含有モノマーと全仕込量の５０〜９９重量％のビニルエステルモノマーを重合系に仕込んで重合を開始する。本発明においては、最初のビニルエステル系モノマーの仕込量を全仕込量の５０〜９９重量％（さらには６０〜９９重量％、特には７０〜９９重量％、殊に８０〜９６重量％）にすることが重要で、かかる仕込量が上記の範囲を外れるときは、成形されたフィルムに着色したり、懸濁重合用分散剤用途においては発泡を抑制することができなかったり、また、製品の収率も低下して本発明の目的を達成することが困難となる。
【００１９】
オキシアルキレン基含有モノマーとビニルエステルモノマーのそれぞれの全仕込量は、目的とするオキシアルキレン基含有ビニルエステル系重合体あるいはそのケン化物中のオキシアルキレン基含有量により、任意に決定すればよく、かかる含有量としては、０．１〜１５モル％程度の範囲から選択することが好ましく、かかる含有量が０．１モル％未満ではオキシアルキレン基含有の効果（例えば、ケン化物の水溶性、成形性、結晶性低下効果等）を充分に得られないことがあり、逆に１５モル％を越えるとケン化物を水溶液として使用する際に水溶液の粘度が上がりすぎて作業性が低下したり、熱安定性が低下して製造工程中に多量の不溶解物が生成することがあり好ましくない。
【００２０】
上記のモノマーを共重合するにあたっては、重合触媒および重合溶媒の存在下に行われ、かかる重合触媒としては限定されないが、アゾビスイソブチロニトリル、過酸化アセチル、過酸化ベンゾイル、過酸化ラウロイルなどの公知のラジカル重合触媒を用いて行われ、かかる触媒は通常後述の有機溶剤に溶解して仕込まれる。
【００２１】
また、重合溶媒としては、メタノール、エタノール、プロパノール、ブタノール等のアルコール類などの有機溶剤が用いられ、通常はメタノールが好適に用いられる。
【００２２】
本発明においては、かかる重合触媒の仕込み方法については特に制限はないが重合開始時に一括仕込みする方法、反応途中に重合触媒の一部を分割仕込みする方法、反応途中に重合触媒の一部を連続滴下する方法などがある。なお、本発明においては、上記のようにビニルエステルモノマーを追加仕込みするので、追加仕込み後も重合反応が進行することが必要条件であり、そのために該追加仕込前後に重合触媒の一部を追加仕込みすることが好ましい。
なお、重合温度は、特に制限はなく、３０℃程度から加圧下においては沸点を超える温度で実施してもよいが、通常３０℃〜沸点程度の範囲が好適である。
【００２３】
かくして、重合が開始されるのであるが、本発明においては、重合を開始して、仕込んだビニルエステルモノマーの重合率が５０％以上（さらには６０％以上、特には７０％以上、殊に８０％以上）の時点において残りのビニルエステルモノマーを仕込むことも重要で、かかる重合率が５０％未満の時点で残りのビニルエステルモノマーを仕込んでも、成形されたフィルムに着色したり、懸濁重合用分散剤用途においては発泡を抑制することができなかったり、また、製品の収率も低下して本発明の目的を達成することが困難となる。
かかるビニルエステルモノマーの（追加）仕込にあたっては、特に仕込み方法に制限はないが追加仕込の全量を一度に仕込む方法、分割仕込みする方法、連続滴下仕込する方法等を挙げることができる。
【００２４】
また、ビニルエステルモノマーの追加仕込み時間は特に限定されないが、一括仕込みの場合で３０秒〜５分程度、分割仕込みや連続滴下仕込みの場合で５分〜５時間程度である。さらに追加仕込み終了後に必要に応じて１分〜１２０分程度の追い込み工程を設けても良いが追い込み工程が長くなりすぎると製品の収率が低下する傾向にあり好ましくない。
【００２５】
ビニルエステルモノマーを分割仕込みする場合、通常は等量分割する方法を採るが、分割量を変化させることも可能である。また、ビニルエステルモノマーを連続滴下仕込みする場合については通常、一定速度で仕込む方法を採るが、連続滴下速度を変化させることも可能である。
【００２６】
また、追加仕込するビニルエステルモノマーを系内に仕込む方法としては特に限定されないが、シャワー方式で仕込む方法、コンデンサー還流液に混合して仕込む方法、直接流し込んで仕込む方法等を挙げることができる。また、追加仕込するビニルエステルモノマーは、そのまま系内に仕込んでもよいが、メタノール等の重合溶媒に混合して仕込むことも可能である。また、追加仕込する重合触媒についても重合溶媒に溶解させて仕込むことも可能である。
【００２７】
かくしてオキシアルキレン基含有ビニルエステル系重合体が得られ、かかる重合体は増粘剤、有機系顔料のフィラー等の用途に有用であるが、かかる重合体のケン化物（オキシアルキレン基含有ポリビニルアルコール系樹脂）も、後述する各種用途に大変有用で、かかるケン化物の製造方法についてさらに説明する。
【００２８】
上記で得られたオキシアルキレン基含有ビニルエステル系重合体は、必要に応じて脱モノマー処理が行われてケン化される。
ケン化方式は特に限定されず、バッチ式および連続式のいずれの方法も実施することができる。
【００２９】
ケン化に当たっては、該重合体をアルコール等に溶解してケン化触媒の存在下にケン化が行なわれる。該アルコールとしては、メタノール、エタノール、ブタノール等が挙げられる。アルコール中の該重合体の濃度は２０〜７０重量％（さらには２０〜６０重量％）の範囲から選ばれる。
【００３０】
ケン化触媒としては水酸化ナトリウム、水酸化カリウム、ナトリウムメチラート、ナトリウムエチラート、カリウムメチラート等のアルカリ金属の水酸化物やアルコラートの如きアルカリ触媒を用いることが好ましい。かかる触媒の使用量はビニルエステルモノマー１モルに対して１〜１００ミリモルにすることが必要である。また、必要に応じて水をケン化反応系に加えることもできる。さらに硫酸、塩酸等の酸触媒を用いてケン化反応を行うことも可能である。
【００３１】
かくして、ケン化反応を終了するのであるが、得られるケン化物のケン化度については特に制限はないが、フィルム等の成形用途に用いるときには７０モル％以上（さらには８０モル％以上、特には８５モル％以上）とすることが好ましく、また、懸濁重合用分散剤用途に用いるときには８０モル％以下（さらには１５〜８０モル％、特には２０〜８０モル％）とすることが好ましい。なお、オキシアルキレン基の鎖長や変性度により一概に言えないが、例えばオキシエチレン基の場合は、ケン化度が６５モル％未満のとき、得られたペースト状のケン化物を水に溶媒置換して水溶液として製品化することが可能であり、そのまま該分散（助）剤用途に供することが可能である。また、ケン化度が６５モル％以上のときは、通常ケン化物がケン化溶媒に不溶で固液分離する必要があり、このときにポリビニルアルコール系樹脂のロスが発生することがあり、製品の収率の向上面では、後者の場合に本発明の作用効果の寄与がより期待できる。
【００３２】
なお、ここで言うケン化度とは、オキシアルキレン基含有ビニルエステル共重合体の酢酸ビニル成分が水酸基に変換される割合をモル％で示したものである。
【００３３】
また、得られるオキシアルキレン基含有ポリビニルアルコール系樹脂の平均重合度は特に制限されないが、フィルム等の成形用途においては５００〜２０００（さらには５００〜１８００、特には５００〜１５００）が好ましく、また懸濁重合用分散剤用途においては１００〜６００（さらには１５０〜５５０、特には１５０〜５００）が好ましい。
なお、かかる平均重合度は、ＪＩＳ Ｋ ６７２６に準じて測定されるものである。
【００３４】
かくして、本発明のオキシアルキレン基含有ポリビニルアルコール系樹脂が得られるのであるが、かかる樹脂は、特にフィルム等の成形用途においては、耐着色性に優れた成形物を得ることができ、また、塩化ビニルをはじめとする塩化ビニリデン、スチレン、（メタ）アクリレート、酢酸ビニル等の各種ビニル化合物の懸濁重合用分散剤用途に有用で、かかる用途に供したときには、重合初期の反応時及び重合終了後の未反応モノマー回収時のいずれの場合にも系の発泡が少ないという利点を有するものである。
また、増粘剤、コーティング剤、建材用バインダー、造粒用バインダー、接着剤、感圧接着剤、紙サイズ剤、紙コーティング剤、暫定塗料、親水性付与剤、塗料、顔料分散安定剤、記録媒体（感熱記録紙、インクジェット紙、ＯＨＰ等）加工剤、フィルム、シート、繊維、容器等の成形品、中子、外子などの成形加工材料として用いることもできる。
【００３５】
【実施例】
以下、本発明を実施例によって具体的に説明する。
なお，実施例中「％」、「部」とあるのは、断りのない限り重量基準を意味する。
【００３６】
実施例１
重合缶にオキシエチレン基の平均鎖長（ｎ）が１０のポリオキシエチレンモノアリルエーテル１８．０部と酢酸ビニル８５部、イソプロピルアルコール２９．０部を仕込み、還流状態になるまで昇温した後３０分間還流させてから、アゾビスイソブチロニトリルを全仕込酢酸ビニル量に対して０．１０モル％仕込んで重合を開始した。
反応開始後４時間目にアゾビスイソブチロニトリルを全仕込酢酸ビニル量に対して０．０５モル％追加した。
【００３７】
次いで、酢酸ビニルの（初期仕込酢酸ビニルに対する）重合率が７５％になった時点（重合反応開始後約７時間目）で、残りの酢酸ビニル１５部を一括で追加仕込みした（仕込みに要した時間は約１分）。
反応開始９時間目に冷却用メタノールと禁止剤を加え、反応缶ジャケットを冷却して重合反応を停止して、ポリオキシエチレン基含有酢酸ビニル重合体を得た。かかる重合体の重合率は約９０％であった。
【００３８】
次いで、上記で得られたオキシエチレン基含有酢酸ビニル重合体（樹脂分約５２％の溶液）を連続脱モノマー塔で液中の残存モノマー量が０．１２％になるまでモノマーを追いだし、バッチ式ケン化機に仕込みメタノールを添加してポリ酢酸ビニル濃度を５０％に調整してから、４ミリモル（対酢酸ビニル１モル）の水酸化ナトリウムをメタノール溶液で加えて、ケン化反応（温度３５℃）を行った。ケン化後に酢酸を加えて中和した後、溶剤分を追い出して脱イオン水を加えてポリオキシエチレン基含有ポリビニルアルコール系樹脂の水溶液（濃度３５％）を得た。得られた該ポリビニルアルコール系樹脂のケン化度は４５モル％で、平均重合度は２７０であった。また、製品の収率は９８％であった（表１にも示す）。なお、該収率は、原料仕込量より理論的に算出される生成樹脂量に対する実際の取得樹脂量より計算した。
【００３９】
また、塩化ビニルの懸濁重合用分散助剤としての性能を調べるために、以下の評価を行った。評価結果は表１に示す。
リフラックスコンデンサー（ＲＣ）を装備した反応缶に塩化ビニル５００部、脱気したイオン交換水５００部を供給し、更に塩化ビニル１００部に対して上記で得られたポリオキシエチレン基含有ポリビニルアルコール系樹脂を分散助剤として０．０５７部（固形分換算０．０２部）を供給すると共に主分散剤としてケン化度７９モル％、平均重合度２２００の未変性ポリビニルアルコールを０．０８部導入した。重合缶内温度を５７℃に昇温した後、重合開始剤としてジ−２−エチルヘキシル−オキシジカーボネート及びｔ−ブチルパーオキシネオカーボネートを各々塩化ビニル１００部に対して０．０３部仕込み、これと同時にＲＣを稼働させて、４００ｒｐｍで撹拌しながら４時間重合を行ってポリ塩化ビニルを得た。重合中は、ＲＣの冷却水温度及び反応缶ジャケット温度を制御し、重合反応熱をＲＣと反応缶ジャケットで除熱した。重合反応終了後、反応缶と同じ大きさの未反応モノマー回収容器にポリ塩化ビニルを移送した。かかる移送は反応缶の圧力より回収容器の圧力をより減圧下にして実施した。移送時に反応缶中に発泡はほとんどなく、移送は２５分未満で終了した。移送中と移送後に反応缶及び未反応モノマー回収容器に接続したガスホルダーに未反応モノマーを回収し、移送したポリ塩化ビニルスラリーは脱水、乾燥し、ポリ塩化ビニルを得た。
このときのウエットフォーミングを調べるために、重合開始１時間後の泡立ちの状況を重合缶側面の覗き窓より観察し、液面からの泡の高さを測定して、以下の基準で評価した。
Ａ・・・４ｃｍ未満
Ｂ・・・４〜７ｃｍ未満
Ｃ・・・７〜１０ｃｍ未満
Ｄ・・・１０ｃｍ以上
【００４０】
また、重合終了後の未反応塩化ビニルモノマーを回収する時の発泡性を評価するため、回収容器にポリ塩化ビニルスラリーを移送する時間を測定して、以下の基準で評価した。即ち、発泡が激しい程該スラリーの移送に時間がかかる。
Ａ・・・２５分未満
Ｂ・・・２５〜４０分未満
Ｃ・・・４０〜６０分未満
Ｄ・・・６０分以上
【００４１】
実施例２
実施例１においてイソプロピルアルコール仕込量を２８．０部として、酢酸ビニル１５部を連続滴下仕込（一定速度）で追加した（追加仕込みに要した時間は４０分であった）以外は同様に重合反応を行ってポリオキシエチレン基含有ポリビニルアルコール系樹脂を得た。得られた該ポリビニルアルコール系樹脂のケン化度は４５モル％で、平均重合度は２７０であった。なお、製品の収率は表１に示す。また、実施例１と同様に塩化ビニルの懸濁重合用分散助剤としての性能を調べた。評価結果は表１に示す。
【００４２】
実施例３
実施例１において、平均鎖長（ｎ）が１０のポリオキシエチレンモノアリルエーテル１８．０部と酢酸ビニル９０部、メタノール１２部を仕込み、重合率が８５％になった時点（重合反応開始後約８時間目）で、残りの酢酸ビニル１０部を一括で追加仕込みした（仕込みに要した時間は約１分）以外は同様に行って、オキシエチレン基含有酢酸ビニル重合体を得た。かかる重合体の重合率は約９６％であった。
【００４３】
また、同様にケン化を行って、ポリオキシエチレン基含有ポリビニルアルコール系樹脂を得た。得られた該ポリビニルアルコール系樹脂のケン化度は８８モル％で、平均重合度は６８０であった。なお、製品の収率は表１に示す。
得られたポリオキシエチレン基含有ポリビニルアルコール系樹脂の１０％水溶液を調製して、ＰＥＴフィルム上に流して、厚さ約２００μｍのフィルムを成形し、１８０℃で１０分間熱処理を行って、フィルムの着色性（ＹＩ値）を色差計で測定し、以下のように評価した。評価結果は表１に示す。
○・・・ＹＩ値が１５未満
×・・・ＹＩ値が１５以上
【００４４】
実施例４
実施例１において、ポリオキシエチレンモノアリルエーテル５．８部と酢酸ビニル９５部、メタノール４５部を仕込み、重合率が８８％になった時点（重合反応開始後約９時間目）で、残りの酢酸ビニル５部を一括で追加仕込みした（仕込みに要した時間は約１分）以外は同様に行って、オキシエチレン基含有酢酸ビニル重合体を得た。かかる重合体の重合率は約９６％であった。
また、同様にケン化を行って、ポリオキシエチレン基含有ポリビニルアルコール系樹脂を得た。得られた該ポリビニルアルコール系樹脂のケン化度は９４モル％で、平均重合度は６８０であった。なお、製品の収率は表１に示す。また、実施例３と同様にフィルムの着色性の評価を行った。評価結果は表１に示す。
【００４５】
実施例５
実施例１において、ポリオキシエチレンモノアリルエーテル１１．６部と酢酸ビニル９０部、メタノール１２部を仕込み、重合率が９２％になった時点（重合反応開始後約９．５時間目）で、残りの酢酸ビニル１０部を一括で追加仕込みした（仕込みに要した時間は約１分）以外は同様に行って、オキシエチレン基含有酢酸ビニル重合体を得た。かかる重合体の重合率は約９７％であった。
【００４６】
また、同様にケン化を行って、ポリオキシエチレン基含有ポリビニルアルコール系樹脂を得た。得られた該ポリビニルアルコール系樹脂のケン化度は８８モル％で、平均重合度は６８０であった。なお、製品の収率は表１に示す。また、実施例３と同様にフィルムの着色性の評価を行った。評価結果は表１に示す。
【００４７】
実施例６
実施例１において、ポリオキシエチレンモノアリルエーテルに変えて、ポリオキシプロピレン基の平均鎖長（ｎ）が２０のポリオキシプロピレンモノアリルエーテルを用いた以外は同様に行って、オキシプロピレン基含有酢酸ビニル重合体を得た。かかる重合体の重合率は約９１％であった。
【００４８】
また、同様にケン化を行って、ポリオキシプロピレン基含有ポリビニルアルコール系樹脂を得た。得られた該ポリビニルアルコール系樹脂のケン化度は９８モル％で、平均重合度は５８０であった。なお、製品の収率は表１に示す。また、実施例３と同様にフィルムの着色性の評価を行った。評価結果は表１に示す。
【００４９】
実施例７
実施例４において、メタノールの仕込量を２９．０部、初期の酢酸ビニルの仕込量を９０部として、ポリオキシエチレンモノアリルエーテルに変えて、ポリオキシプロピレン基の平均鎖長（ｎ）が２０のポリオキシプロピレンモノアリルエーテルを用いた以外は同様に行って、オキシプロピレン基含有酢酸ビニル重合体を得た。かかる重合体の重合率は約９６％であった。
【００５０】
また、同様にケン化を行って、ポリオキシプロピレン基含有ポリビニルアルコール系樹脂を得た。得られた該ポリビニルアルコール系樹脂のケン化度は７２モル％で、平均重合度は８５０であった。なお、製品の収率は表１に示す。また、実施例１に準じて塩化ビニルの懸濁重合用主分散剤としての性能を調べた。すなわち、未変性ポリビニルアルコールに変えて上記で得られたポリオキシプロピレン基含有ポリビニルアルコール系樹脂を主分散剤として０．０８部用い、かつ分散助剤としてケン化度４６モル％、平均重合度２５０の未変性ポリビニルアルコールを０．０２部用いた。評価結果は表１に示す。
【００５１】
比較例１
実施例１において酢酸ビニルの全量を初期一括仕込みして、イソプロピルアルコールの仕込量を３１部とした以外は同様に重合反応を行って、オキシエチレン基含有酢酸ビニル重合体を得た。かかる重合体の重合率は約９０％であった。
【００５２】
また、同様にケン化、溶剤置換を行って、ポリオキシエチレン基含有ポリビニルアルコール系樹脂を得た。得られた該ポリビニルアルコール系樹脂のケン化度は４５モル％で、平均重合度は２７０であった。なお、製品の収率は９７％であった。また、実施例１と同様に塩化ビニルの懸濁重合用分散助剤としての性能を調べた。評価結果は表１に示す。
【００５３】
比較例２
実施例３において、酢酸ビニルの全量を初期一括仕込して、メタノールの仕込量を１１．５部とした以外は同様に重合反応を行って、オキシエチレン基含有酢酸ビニル重合体を得た。かかる重合体の重合率は約９６％であった。
【００５４】
また、同様にケン化、溶剤置換を行って、ポリオキシエチレン基含有ポリビニルアルコール系樹脂を得た。得られた該ポリビニルアルコール系樹脂のケン化度は８８モル％で、平均重合度は６８０であった。なお、製品の収率は８８％であった。また、実施例３と同様にフィルムの着色性の評価を行った。評価結果は表１に示す。
【００５５】

【００５６】
【発明の効果】
本発明の製造方法で得られたオキシアルキレン基含有ビニルエステル重合体およびそのケン化物、特に該ケン化物は、フィルム等の成形用途に供したときの透明性に優れ、塩化ビニル等の懸濁重合用分散助剤として使用したときには、重合初期の反応時及び重合終了後の未反応モノマー回収時のいずれの場合にも発泡が抑制できるという利点を有するものである。
また、増粘剤、コーティング剤、建材用バインダー、造粒用バインダー、接着剤、感圧接着剤、紙サイズ剤、紙コーティング剤、暫定塗料、親水性付与剤、塗料、顔料分散安定剤、記録媒体（感熱記録紙、インクジェット紙、ＯＨＰ等）加工剤、フィルム、シート、繊維、容器等の成形品、中子、外子などの成形加工材料として用いることができ、かつ製品の収率もよい。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing an oxyalkylene group-containing vinyl ester polymer, particularly a saponified product thereof. More specifically, the present invention is excellent in coloration resistance when used for molding applications such as films, and for suspension polymerization of vinyl chloride and the like. When used as a dispersant, the oxyalkylene group-containing vinyl ester heavy polymer can suppress foaming in both the initial reaction and the recovery of unreacted monomer after completion of polymerization, and the product yield is improved. The present invention relates to a method for producing a coalescence and a saponified product thereof.
[0002]
[Prior art]
Conventionally, oxyalkylene group-containing vinyl ester polymers and saponified products thereof (oxyalkylene group-containing polyvinyl alcohol resins), particularly saponified products, are used for molding applications such as films and vinyl polymers such as vinyl chloride. It is used as a dispersant for turbid polymerization (main dispersant and dispersion aid).
[0003]
[Problems to be solved by the invention]
In such applications, various performances are required, but in the former film forming application, it is also an important required performance not to be colored due to thermal history, and in the latter suspension polymerization dispersant application. Is where suppression of foaming is required both in the initial reaction and in the recovery of the unreacted monomer after completion of the polymerization.
[0004]
[Means for Solving the Problems]
Therefore, the present inventor conducted a study from the production aspect in order to obtain an oxyalkylene group-containing polyvinyl alcohol resin that can answer these required performances.Shown by the following general formulaOxyalkylene group-containing monomers and vinyl ester monomersAnd in an organic solventIn the copolymerization, the total amount of oxyalkylene group-containing monomer and 50 to 99% by weight of the total amount of vinyl ester monomer were charged into the polymerization system, and the polymerization was started. The polymerization rate of the charged vinyl ester monomer was 50%. It was found that an oxyalkylene group-containing vinyl ester polymer and a saponified product thereof could be obtained by charging the remaining vinyl ester monomers at the above time points, and the present invention was completed. Further, the oxyalkylene group-containing vinyl ester polymer and the saponified product thereof obtained by the method of the present invention also have a feature of excellent product yield.
[Chemical 1]

(Where R is hydrogen or a methyl group, R ₁ , R ₂ Is hydrogen or an alkyl group, R ₃ Is hydrogen, an alkyl group, an alkyl ester group, an alkylamide group, a sulfonic acid group, a phenyl group or a substituted phenyl group, and n is a positive integer. )
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
[0006]
The oxyalkylene group-containing monomer used in the present invention contains an oxyalkylene group represented by the following general formula (1).
[Chemical 1]

(However, R₁, R₂Is hydrogen or an alkyl group, R₃Is hydrogen, an alkyl group, an alkyl ester group, an alkylamide group, a sulfonic acid group, a phenyl group or a substituted phenyl group, and n is a positive integer. )
[0007]
In the above general formula (1), the number of n, that is, the average chain length of the oxyalkylene group is about 2 to 300, and is preferably about 5 to 60 in view of workability during polymerization. Specific examples of the oxyalkylene group include a polyoxyethylene group, a polyoxypropylene group, and a polyoxybutylene group.
[0008]
  As a monomer having an oxyalkylene group(Meth) allyl ether type compounds represented by the following general formula can be mentioned, and specific examples include polyoxyethylene (meth) allyl ether, polyoxypropylene (meth) allyl ether and the like.
[Chemical 2]

(Where R is hydrogen or a methyl group, R ₁ , R ₂ , R ₃ , N are the same as above. )
[0012]
Vinyl ester monomers that (co) polymerize with oxyalkylene group-containing monomers include vinyl formate, vinyl acetate, vinyl trifluoroacetate, vinyl propionate, vinyl butyrate, vinyl caprate, vinyl laurate, vinyl versatate, palmitic acid Although vinyl, vinyl stearate, vinyl pivalate, etc. can be mentioned, vinyl acetate is preferably used industrially.
[0013]
In the present invention, in addition to the oxyalkylene group-containing monomer and the vinyl ester monomer as described above, other general monomers may be allowed to coexist in an amount of 50 mol% or less as long as the object of the present invention is not impaired. These monomers are exemplified below.
[Ethylenically unsaturated carboxylic acid and its alkyl ester, etc.]
Methyl crotonate, ethyl crotonate, methyl itaconate, ethyl itaconate, methyl sorbate, ethyl sorbate, monoalkyl maleate, dialkyl maleate, alkyl oleate, methyl (meth) acrylate, (meth) Ethyl acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, decyl (meth) acrylate, (meth) acrylic Examples include hexadecyl acid and octadecyl (meth) acrylate.
[0014]
[Allyl ester of saturated carboxylic acid]
Allyl stearate, allyl laurate, allyl coconut fatty acid, allyl octylate, allyl butyrate and the like.
[Α-olefin]
Ethylene, propylene, α-hexene, α-octene, α-decene, α-dodecene, α-hexadecene, α-octadecene and the like.
[Ethylenically unsaturated carboxylic acid]
(Meth) acrylic acid, crotonic acid, (anhydrous) maleic acid, fumaric acid, itaconic acid, and alkali metal salts and ammonium salts thereof.
[0015]
[Alkyl vinyl ether]
Propyl vinyl ether, butyl vinyl ether, hexyl vinyl ether, octyl vinyl ether, decyl vinyl ether, dodecyl vinyl ether, tetradecyl vinyl ether, hexadecyl vinyl ether, octadecyl vinyl ether and the like.
[0016]
[Alkyl allyl ether]
Propyl allyl ether, butyl allyl ether, hexyl allyl ether, octyl allyl ether, decyl allyl ether, dodecyl allyl ether, tetradecyl allyl ether, hexadecyl allyl ether, octadecyl allyl ether, and the like.
Other thiols containing (meth) acrylamide, (meth) acrylonitrile, (meth) allyl sulfonate, ethylenically unsaturated sulfonate, styrene, vinyl chloride, amino group, ammonium group, carboxyl group, sulfonic acid group, etc. It is also possible to use a chain transfer agent of the system.
[0017]
The greatest feature of the present invention is that when the above oxyalkylene group-containing monomer and vinyl ester monomer are polymerized, the total amount of oxyalkylene group-containing monomer and 50 to 99% by weight of the total amount of vinyl ester monomer are polymerized. The polymerization is started by charging into the system, and the remaining vinyl ester monomer is charged when the polymerization rate of the vinyl ester monomer with respect to the charged amount is 50 to 99%, and this method will be specifically described.
[0018]
First, the polymerization system (usually a polymerization can) is charged with the total amount of oxyalkylene group-containing monomer and 50 to 99% by weight of the total amount of vinyl ester monomer, and the polymerization is started. In the present invention, the initial vinyl ester monomer charge is 50 to 99% by weight (more preferably 60 to 99% by weight, particularly 70 to 99% by weight, especially 80 to 96% by weight) of the total charge. When the charged amount is out of the above range, the molded film may be colored, or foaming may not be suppressed in a dispersant for suspension polymerization. The yield also decreases, making it difficult to achieve the object of the present invention.
[0019]
The total amount of each of the oxyalkylene group-containing monomer and the vinyl ester monomer may be arbitrarily determined depending on the oxyalkylene group content in the target oxyalkylene group-containing vinyl ester polymer or saponified product thereof. The content is preferably selected from the range of about 0.1 to 15 mol%, and if the content is less than 0.1 mol%, the effect of containing an oxyalkylene group (for example, water solubility and moldability of saponified product) If the saponification product is used as an aqueous solution, the viscosity of the aqueous solution increases too much, and the workability decreases or the heat stability is reduced. It is not preferable because the properties may decrease and a large amount of insoluble matter may be generated during the production process.
[0020]
The copolymerization of the above monomers is performed in the presence of a polymerization catalyst and a polymerization solvent, and the polymerization catalyst is not limited, but includes azobisisobutyronitrile, acetyl peroxide, benzoyl peroxide, lauroyl peroxide, and the like. The known radical polymerization catalyst is generally used, and the catalyst is usually charged after being dissolved in an organic solvent described later.
[0021]
Moreover, as a polymerization solvent, organic solvents, such as alcohols, such as methanol, ethanol, propanol, and butanol, are used, and methanol is used suitably normally.
[0022]
In the present invention, there is no particular limitation on the method for charging the polymerization catalyst, but a method of batch charging at the start of polymerization, a method of charging a part of the polymerization catalyst in the middle of the reaction, and a part of the polymerization catalyst continuously in the middle of the reaction. There is a method of dripping. In the present invention, since the vinyl ester monomer is additionally charged as described above, it is a necessary condition that the polymerization reaction proceeds even after the additional charging. For this reason, a part of the polymerization catalyst is added before and after the additional charging. It is preferable to charge.
The polymerization temperature is not particularly limited, and may be carried out at a temperature from about 30 ° C. to a temperature exceeding the boiling point under pressure. Usually, a range of about 30 ° C. to about the boiling point is suitable.
[0023]
Thus, although the polymerization is started, in the present invention, the polymerization is started and the polymerization rate of the charged vinyl ester monomer is 50% or more (more than 60%, particularly more than 70%, especially more than 80%. %)), It is also important to charge the remaining vinyl ester monomer, and even if the remaining vinyl ester monomer is charged when the polymerization rate is less than 50%, the molded film is colored or used for suspension polymerization. In the use of a dispersant, foaming cannot be suppressed, and the yield of the product is lowered, making it difficult to achieve the object of the present invention.
In the (additional) charging of the vinyl ester monomer, the charging method is not particularly limited, and examples thereof include a method of charging the entire amount of additional charging at once, a method of split charging, and a method of continuous dropping charging.
[0024]
The additional charging time of the vinyl ester monomer is not particularly limited, but is about 30 seconds to 5 minutes in the case of batch charging and about 5 minutes to 5 hours in the case of divided charging or continuous dropping charging. Further, after completion of the additional preparation, a follow-up process of about 1 minute to 120 minutes may be provided as necessary. However, if the follow-up process becomes too long, the yield of the product tends to decrease, which is not preferable.
[0025]
When the vinyl ester monomer is dividedly charged, a method of equally dividing the vinyl ester monomer is usually employed, but the dividing amount can be changed. In addition, when the vinyl ester monomer is continuously dropped, a method of charging at a constant rate is usually employed, but the continuous dropping rate can be changed.
[0026]
Further, the method of charging the vinyl ester monomer to be additionally charged into the system is not particularly limited, and examples thereof include a method of charging by a shower method, a method of mixing and charging in a condenser reflux liquid, and a method of charging by direct injection. Further, the vinyl ester monomer to be additionally charged may be charged into the system as it is, but can also be charged by mixing in a polymerization solvent such as methanol. Further, it is also possible to charge the additional polymerization catalyst by dissolving it in a polymerization solvent.
[0027]
Thus, an oxyalkylene group-containing vinyl ester polymer is obtained, and such a polymer is useful for applications such as thickeners and fillers for organic pigments. Resin) is also very useful for various applications described later, and a method for producing such a saponified product will be further described.
[0028]
The oxyalkylene group-containing vinyl ester polymer obtained above is saponified by performing a monomer removal treatment as necessary.
The saponification method is not particularly limited, and both batch and continuous methods can be carried out.
[0029]
In saponification, the polymer is dissolved in alcohol or the like and saponification is performed in the presence of a saponification catalyst. Examples of the alcohol include methanol, ethanol, butanol and the like. The concentration of the polymer in the alcohol is selected from the range of 20 to 70% by weight (or 20 to 60% by weight).
[0030]
As the saponification catalyst, an alkali catalyst such as an alkali metal hydroxide or alcoholate such as sodium hydroxide, potassium hydroxide, sodium methylate, sodium ethylate or potassium methylate is preferably used. The amount of the catalyst used must be 1 to 100 millimoles per mole of vinyl ester monomer. Moreover, water can also be added to a saponification reaction system as needed. Furthermore, it is also possible to perform a saponification reaction using acid catalysts, such as a sulfuric acid and hydrochloric acid.
[0031]
Thus, the saponification reaction is completed, but the saponification degree of the saponified product obtained is not particularly limited, but when used for molding applications such as a film, it is 70 mol% or more (further 80 mol% or more, especially 85 mol% or more), and when used for a dispersant for suspension polymerization, it is preferably 80 mol% or less (more preferably 15 to 80 mol%, particularly 20 to 80 mol%). Although it cannot be generally stated depending on the chain length or modification degree of the oxyalkylene group, for example, in the case of the oxyethylene group, when the degree of saponification is less than 65 mol%, the obtained paste-like saponified product is replaced with water. Then, it can be commercialized as an aqueous solution and can be used as it is for the dispersing (auxiliary) agent. When the saponification degree is 65 mol% or more, the saponification product is usually insoluble in the saponification solvent and needs to be solid-liquid separated. At this time, loss of the polyvinyl alcohol resin may occur. In terms of yield improvement, the latter case can be expected to contribute more to the effects of the present invention.
[0032]
In addition, the saponification degree said here shows the ratio in which the vinyl acetate component of an oxyalkylene group containing vinyl ester copolymer is converted into a hydroxyl group in mol%.
[0033]
The average degree of polymerization of the resulting oxyalkylene group-containing polyvinyl alcohol-based resin is not particularly limited, but is preferably 500 to 2000 (more preferably 500 to 1800, particularly 500 to 1500) for molding applications such as films. 100 to 600 (further 150 to 550, especially 150 to 500) is preferable for use in a dispersant for turbid polymerization.
The average degree of polymerization is measured according to JIS K 6726.
[0034]
Thus, although the oxyalkylene group-containing polyvinyl alcohol resin of the present invention can be obtained, such a resin can provide a molded article having excellent color resistance, particularly in a molding application such as a film. Useful for dispersants for suspension polymerization of various vinyl compounds such as vinylidene chloride such as vinyl, styrene, (meth) acrylate, vinyl acetate, etc. When used in such applications, during the initial polymerization reaction and after completion of polymerization In any case when the unreacted monomer is recovered, there is an advantage that the foaming of the system is small.
Also, thickeners, coating agents, building material binders, granulating binders, adhesives, pressure sensitive adhesives, paper sizing agents, paper coating agents, provisional paints, hydrophilicity imparting agents, paints, pigment dispersion stabilizers, recording It can also be used as a molding processing material for a medium (thermal recording paper, ink jet paper, OHP, etc.), a molded product such as a film, a sheet, a fiber or a container, a core, or an outer core.
[0035]
【Example】
Hereinafter, the present invention will be specifically described by way of examples.
In the examples, “%” and “part” mean weight basis unless otherwise specified.
[0036]
Example 1
A polymerization can was charged with 18.0 parts of polyoxyethylene monoallyl ether having an average chain length (n) of oxyethylene group of 10, 85 parts of vinyl acetate and 29.0 parts of isopropyl alcohol, and heated to a reflux state. After refluxing for 30 minutes, azobisisobutyronitrile was charged at 0.10 mol% with respect to the total amount of vinyl acetate, and polymerization was started.
At 4 hours after the start of the reaction, 0.05 mol% of azobisisobutyronitrile was added to the total amount of vinyl acetate charged.
[0037]
Next, when the polymerization rate of vinyl acetate (relative to the initial charge of vinyl acetate) reached 75% (about 7 hours after the start of the polymerization reaction), the remaining 15 parts of vinyl acetate were additionally charged all together (necessary for preparation) Time is about 1 minute).
At 9 hours from the start of the reaction, cooling methanol and an inhibitor were added, the reactor jacket was cooled to terminate the polymerization reaction, and a polyoxyethylene group-containing vinyl acetate polymer was obtained. The polymerization rate of such a polymer was about 90%.
[0038]
Next, the oxyethylene group-containing vinyl acetate polymer obtained in the above (solution having a resin content of about 52%) was driven off in a continuous demonomer tower until the amount of residual monomer in the liquid reached 0.12%, and the batch was removed. The saponification machine was charged with methanol to adjust the polyvinyl acetate concentration to 50%, and then 4 mmol (1 mol of vinyl acetate) of sodium hydroxide was added as a methanol solution to saponification reaction (temperature 35 ° C). After saponification, the mixture was neutralized by adding acetic acid, and then the solvent was removed and deionized water was added to obtain an aqueous solution (concentration 35%) of a polyoxyethylene group-containing polyvinyl alcohol resin. The obtained polyvinyl alcohol-based resin had a saponification degree of 45 mol% and an average polymerization degree of 270. The product yield was 98% (also shown in Table 1). The yield was calculated from the actual amount of resin obtained relative to the amount of product resin theoretically calculated from the raw material charge.
[0039]
Moreover, in order to investigate the performance as a dispersion aid for suspension polymerization of vinyl chloride, the following evaluation was performed. The evaluation results are shown in Table 1.
A reaction vessel equipped with a reflux condenser (RC) is supplied with 500 parts of vinyl chloride and 500 parts of degassed ion-exchanged water, and the polyoxyethylene group-containing polyvinyl alcohol system obtained above for 100 parts of vinyl chloride. 0.057 parts (0.02 part in terms of solid content) was supplied as a dispersion aid, and 0.08 parts of unmodified polyvinyl alcohol having a saponification degree of 79 mol% and an average polymerization degree of 2200 were introduced as a main dispersant. . After raising the internal temperature of the polymerization can to 57 ° C., 0.03 parts of di-2-ethylhexyl-oxydicarbonate and t-butylperoxyneocarbonate as polymerization initiators were added to 100 parts of vinyl chloride. Simultaneously, RC was operated and polymerization was performed for 4 hours while stirring at 400 rpm to obtain polyvinyl chloride. During the polymerization, the RC cooling water temperature and the reactor jacket temperature were controlled, and the polymerization reaction heat was removed by the RC and reactor jacket. After completion of the polymerization reaction, the polyvinyl chloride was transferred to an unreacted monomer recovery container having the same size as the reaction vessel. This transfer was carried out with the pressure of the recovery container being reduced under a pressure of the reaction vessel. There was almost no foaming in the reaction can at the time of transfer, and transfer was completed in less than 25 minutes. During and after the transfer, unreacted monomer was recovered in a gas holder connected to the reactor and the unreacted monomer recovery container, and the transferred polyvinyl chloride slurry was dehydrated and dried to obtain polyvinyl chloride.
In order to investigate the wet forming at this time, the state of foaming 1 hour after the start of polymerization was observed from the observation window on the side of the polymerization can, and the height of the foam from the liquid surface was measured and evaluated according to the following criteria.
A ... less than 4cm
B ... less than 4-7cm
C ... less than 7-10cm
D ... 10cm or more
[0040]
Further, in order to evaluate foamability when recovering the unreacted vinyl chloride monomer after the completion of polymerization, the time for transferring the polyvinyl chloride slurry to the recovery container was measured and evaluated according to the following criteria. That is, the more foaming, the longer it takes to transfer the slurry.
A: Less than 25 minutes
B ... Less than 25-40 minutes
C ... Less than 40-60 minutes
D ... 60 minutes or more
[0041]
Example 2
In Example 1, the polymerization reaction was the same except that the amount of isopropyl alcohol charged was 28.0 parts and 15 parts of vinyl acetate was added by continuous dropping (constant speed) (the time required for the additional charging was 40 minutes). To obtain a polyoxyethylene group-containing polyvinyl alcohol resin. The obtained polyvinyl alcohol-based resin had a saponification degree of 45 mol% and an average polymerization degree of 270. The product yield is shown in Table 1. Further, the performance of vinyl chloride as a dispersion aid for suspension polymerization was examined in the same manner as in Example 1. The evaluation results are shown in Table 1.
[0042]
Example 3
In Example 1, when 18.0 parts of polyoxyethylene monoallyl ether having an average chain length (n) of 10, 90 parts of vinyl acetate and 12 parts of methanol were charged and the polymerization rate reached 85% (after the initiation of the polymerization reaction) About 8 hours), the same procedure was performed except that 10 parts of the remaining vinyl acetate was added all at once (the time required for charging was about 1 minute) to obtain an oxyethylene group-containing vinyl acetate polymer. The polymerization rate of such a polymer was about 96%.
[0043]
Moreover, saponification was performed in the same manner to obtain a polyoxyethylene group-containing polyvinyl alcohol resin. The obtained polyvinyl alcohol resin had a saponification degree of 88 mol% and an average polymerization degree of 680. The product yield is shown in Table 1.
A 10% aqueous solution of the obtained polyoxyethylene group-containing polyvinyl alcohol resin was prepared and poured onto a PET film to form a film having a thickness of about 200 μm, and heat-treated at 180 ° C. for 10 minutes. The colorability (YI value) was measured with a color difference meter and evaluated as follows. The evaluation results are shown in Table 1.
○ ... YI value is less than 15
× ・ ・ ・ YI value is 15 or more
[0044]
Example 4
In Example 1, 5.8 parts of polyoxyethylene monoallyl ether, 95 parts of vinyl acetate and 45 parts of methanol were charged, and when the polymerization rate reached 88% (about 9 hours after the start of the polymerization reaction), the remaining An oxyethylene group-containing vinyl acetate polymer was obtained in the same manner except that 5 parts of vinyl acetate was added all at once (the time required for charging was about 1 minute). The polymerization rate of such a polymer was about 96%.
Moreover, saponification was performed in the same manner to obtain a polyoxyethylene group-containing polyvinyl alcohol resin. The obtained polyvinyl alcohol resin had a saponification degree of 94 mol% and an average polymerization degree of 680. The product yield is shown in Table 1. Further, the colorability of the film was evaluated in the same manner as in Example 3. The evaluation results are shown in Table 1.
[0045]
Example 5
In Example 1, 11.6 parts of polyoxyethylene monoallyl ether, 90 parts of vinyl acetate and 12 parts of methanol were charged, and when the polymerization rate reached 92% (about 9.5 hours after the start of the polymerization reaction), The same procedure was performed except that 10 parts of the remaining vinyl acetate was added all at once (the time required for charging was about 1 minute) to obtain an oxyethylene group-containing vinyl acetate polymer. The polymerization rate of such a polymer was about 97%.
[0046]
Moreover, saponification was performed in the same manner to obtain a polyoxyethylene group-containing polyvinyl alcohol resin. The obtained polyvinyl alcohol resin had a saponification degree of 88 mol% and an average polymerization degree of 680. The product yield is shown in Table 1. Further, the colorability of the film was evaluated in the same manner as in Example 3. The evaluation results are shown in Table 1.
[0047]
Example 6
The same procedure as in Example 1 was carried out except that polyoxyethylene monoallyl ether was used instead of polyoxypropylene monoallyl ether having an average chain length (n) of 20 polyoxypropylene groups. A vinyl polymer was obtained. The polymerization rate of such a polymer was about 91%.
[0048]
Moreover, saponification was performed in the same manner to obtain a polyoxypropylene group-containing polyvinyl alcohol resin. The obtained polyvinyl alcohol resin had a saponification degree of 98 mol% and an average polymerization degree of 580. The product yield is shown in Table 1. Further, the colorability of the film was evaluated in the same manner as in Example 3. The evaluation results are shown in Table 1.
[0049]
Example 7
In Example 4, the charge amount of methanol was 29.0 parts, the charge amount of initial vinyl acetate was 90 parts, and instead of polyoxyethylene monoallyl ether, the average chain length (n) of the polyoxypropylene group was 20 The same procedure was performed except that polyoxypropylene monoallyl ether was used to obtain a vinyl acetate polymer containing an oxypropylene group. The polymerization rate of such a polymer was about 96%.
[0050]
Moreover, saponification was performed in the same manner to obtain a polyoxypropylene group-containing polyvinyl alcohol resin. The obtained polyvinyl alcohol resin had a saponification degree of 72 mol% and an average polymerization degree of 850. The product yield is shown in Table 1. Further, according to Example 1, the performance of vinyl chloride as a main dispersant for suspension polymerization was examined. That is, 0.08 parts of the polyoxypropylene group-containing polyvinyl alcohol resin obtained above instead of unmodified polyvinyl alcohol was used as the main dispersant, and the saponification degree was 46 mol% and the average degree of polymerization was 250. 0.02 part of unmodified polyvinyl alcohol was used. The evaluation results are shown in Table 1.
[0051]
Comparative Example 1
A polymerization reaction was carried out in the same manner as in Example 1 except that the total amount of vinyl acetate was initially charged all at once and the amount of isopropyl alcohol charged was 31 parts to obtain an oxyethylene group-containing vinyl acetate polymer. The polymerization rate of such a polymer was about 90%.
[0052]
Similarly, saponification and solvent substitution were performed to obtain a polyoxyethylene group-containing polyvinyl alcohol resin. The obtained polyvinyl alcohol-based resin had a saponification degree of 45 mol% and an average polymerization degree of 270. The product yield was 97%. Further, the performance of vinyl chloride as a dispersion aid for suspension polymerization was examined in the same manner as in Example 1. The evaluation results are shown in Table 1.
[0053]
Comparative Example 2
In Example 3, the polymerization reaction was carried out in the same manner except that the entire amount of vinyl acetate was initially batch charged and the amount of methanol charged was 11.5 parts to obtain an oxyethylene group-containing vinyl acetate polymer. The polymerization rate of such a polymer was about 96%.
[0054]
Similarly, saponification and solvent substitution were performed to obtain a polyoxyethylene group-containing polyvinyl alcohol resin. The obtained polyvinyl alcohol resin had a saponification degree of 88 mol% and an average polymerization degree of 680. The product yield was 88%. Further, the colorability of the film was evaluated in the same manner as in Example 3. The evaluation results are shown in Table 1.
[0055]

[0056]
【The invention's effect】
The oxyalkylene group-containing vinyl ester polymer obtained by the production method of the present invention and a saponified product thereof, in particular, the saponified product is excellent in transparency when used for molding applications such as a film, and is a suspension polymerization of vinyl chloride or the like. When used as a dispersion aid, it has the advantage that foaming can be suppressed both in the reaction at the initial stage of polymerization and in the recovery of unreacted monomer after the completion of polymerization.
Also, thickeners, coating agents, building material binders, granulating binders, adhesives, pressure sensitive adhesives, paper sizing agents, paper coating agents, provisional paints, hydrophilicity imparting agents, paints, pigment dispersion stabilizers, recording Can be used as a medium (thermal recording paper, ink jet paper, OHP, etc.) processing agent, film, sheet, fiber, molded product such as container, core, outer core, etc., and the product yield is also good .

Claims (3)

In copolymerizing an oxyalkylene group-containing monomer represented by the following general formula and a vinyl ester monomer in an organic solvent , the total amount of oxyalkylene group-containing monomer and 50 to 99% by weight of the total amount of vinyl ester monomer And the remaining vinyl ester monomer is charged when the polymerization rate of the charged vinyl ester monomer is 50% or more, and a method for producing an oxyalkylene group-containing vinyl ester polymer is provided. .

(Where R is hydrogen or a methyl group, R ₁ and R ₂ are hydrogen or an alkyl group, R ₃ is hydrogen, an alkyl group, an alkyl ester group, an alkylamide group, a sulfonic acid group, a phenyl group or a substituted phenyl group. , N represents a positive integer.) A method for producing a saponified oxyalkylene group-containing vinyl ester polymer obtained by further saponifying the oxyalkylene group-containing vinyl ester polymer obtained in claim 1. The process according to claim 2 Symbol placement oxyalkylene group-containing polyvinyl ester saponification products, wherein an average polymerization degree of the oxyalkylene group-containing polyvinyl ester saponification products is 100-2000.