JP3608101B2 - Method for producing water-soluble polymer dispersion - Google Patents

Description

（但し、式中、ＡはＯまたはＮＨ；ＢはＣ_２ Ｈ_４ 、Ｃ_３ Ｈ_６ 、Ｃ_３ Ｈ_５ ＯＨ；Ｒ^１ はＨまたはＣＨ_３ ；Ｒ^２ ，Ｒ^３ は炭素数１〜４のアルキル基；Ｒ^４ は水素または炭素数１〜４のアルキル基あるいはベンジル基；Ｘ⁻ は対イオンを表す。）
【０００７】
【化４】

（但し、式中、ＡはＯまたはＮＨ；ＢはＣ_２ Ｈ_４ 、Ｃ_３ Ｈ_６ 、Ｃ_３ Ｈ_５ ＯＨ；Ｒ^５ ，Ｒ^６ ，Ｒ^７ ，Ｒ^８ はＨまたはＣＨ_３ 、Ｘ⁻ は対イオンを表す。）
【０００８】
また本発明においては、前記分散剤が、５０〜１００モル％のジメチルアミノエチル（メタ）アクリレート塩、ジメチルアミノプロピル（メタ）アクリルアミド塩、ジ（メタ）アリルアミン塩、（メタ）アクリロイルオキシエチルトリメチルアンモニウムクロリド、（メタ）アクリルアミドプロピルトリメチルアンモニウムクロリド、ジメチルジアリルアンモニウムクロリドまたはそれらの混合物、の中から選ばれる少なくとも１種のカチオン性単量体、および５０〜０モル％のアクリルアミドを重合したカチオン性高分子電解質であることが好ましい。
【０００９】
さらに本発明では、上記方法において、塩水溶液を形成する塩が２価アニオン塩であることが好ましい。
【００１０】
また、前記スルホン基を持った環式化合物およびその塩としては、２，４−ジメチルベンゼンスルホン酸、ｐ−トルエンスルホン酸、ベンゼンスルホン酸、ナフタレン−１，５−ジスルホン酸、１−ナフトール−３，６−ジスルホン酸、ナフタレン−１，３，６−トリスルホン酸、およびそれらの塩であることが好ましい。
【００１１】
またさらに、前記増粘抑制剤の添加量は、反応液の重量に対して１０ｐｐｍから１００００ｐｐｍであることが好ましい。
【００１２】
【発明の実施の形態】
以下、本発明を詳細に説明する。
本発明は、二重結合を有する水溶性単量体を、その単量体を溶解するが生成重合体を溶解しない塩水溶液中で、この塩水溶液に可溶な高分子電解質からなる分散剤の共存下に、撹拌しながら重合し、塩水溶液に分散した微細な重合体粒子を得る水溶性重合体分散液の製造方法において、スルホン基を持った環式化合物あるいはその塩を少なくとも１種、増粘抑制剤として添加することを特徴とする水溶性重合体分散液の製造方法である。
【００１３】
本発明に用いられる二重結合を有する水溶性単量体は、ジアルキルアミノアルキル（メタ）アクリレートのアミン塩およびその四級化物、ジアルキルアミノアルキル（メタ）アクリルアミドのアミン塩およびその四級化物、ジアルキルアミノヒドロキシプロピル（メタ）アクリレートのアミン塩およびその四級化物、ジアルキルアミノヒドロキシプロピル（メタ）アクリルアミドのアミン塩およびその四級化物、ジアリルアミン塩およびその四級化物等のカチオン性単量体、（メタ）アクリルアミド、Ｎ−ビニルカルボン酸アミド、アクリロニトリル、酢酸ビニル等のノニオン性単量体、（メタ）アクリル酸、アクリルアミド−２−メチルプロパンスルホン酸、イタコン酸等のアニオン性単量体およびこれらの混合物の中から適宜選ばれる。
【００１４】
これら二重結合を有する水溶性単量体を具体的にあげると、カチオン性単量体としてはジメチルアミノエチル（メタ）アクリレートの塩酸あるいは硫酸塩、（メタ）アクリロイルオキシエチルトリメチルアンモニウムクロリド、（メタ）アクリロイルオキシエチルジメチルベンジルアンモニウムクロリド、ジメチルアミノプロピル（メタ）アクリルアミドの塩酸あるいは硫酸塩、（メタ）アクリルアミドプロピルトリメチルアンモニウムクロリド、（メタ）アクリルアミドプロピルジメチルベンジルアンモニウムクロリド、ジメチルアミノヒドロキシプロピル（メタ）アクリレートの塩酸あるいは硫酸塩、（メタ）アクリロイルオキシヒドロキシプロピルトリメチルアンモニウムクロリド、（メタ）アクリロイルオキシヒドロキシプロピルジメチルベンジルアンモニウムクロリド、ジアリルジメチルアンモニウムクロリド、ノニオン性単量体としては（メタ）アクリルアミド、Ｎ−ビニルホルムアミド、Ｎ−ビニルアセトアミド、ヒドロキシ（メタ）アクリレート、アニオン性単量体としては（メタ）アクリル酸、アクリルアミド−２−メチルプロパンスルホン酸、イタコン酸等であるが、これらに限定されるものではない。また、アクリロニトリル、酢酸ビニル、スチレン等の疎水性単量体も重合体が水溶性を保つ限りにおいては、共重合することが出来る。
【００１５】
本発明の水溶性重合体分散液を形成する高分子は上記単量体の重合物であり、特に有用な重合物はカチオン性単量体のみの重合物、あるいはカチオン性単量体とアクリルアミド等ノニオン性単量体との共重合物等のカチオン性高分子、カチオン性単量体とアクリルアミド等ノニオン性単量体とアクリル酸等アニオン性単量体との共重合物である両性高分子ならびにアクリルアミド等ノニオン性単量体の単独重合体であるノニオン性高分子である。
【００１６】
よって本発明に用いられる、さらに好ましい二重結合を有する水溶性単量体は０〜５０モル％のアクリル酸、０〜１００モル％のアクリルアミドおよび０〜１００モル％の下記式１および／または下記式２であらわされるカチオン性単量体である。
【００１７】
【化５】

（但し、式中、ＡはＯまたはＮＨ；ＢはＣ_２ Ｈ_４ 、Ｃ_３ Ｈ_６ 、Ｃ_３ Ｈ_５ ＯＨ；Ｒ^１ はＨまたはＣＨ_３ ；Ｒ^２ ，Ｒ^３ は炭素数１〜４のアルキル基；Ｒ^４ は水素または炭素数１〜４のアルキル基あるいはベンジル基；Ｘ⁻ は対イオンを表す。）
【００１８】
【化６】

（但し、式中、ＡはＯまたはＮＨ；ＢはＣ_２ Ｈ_４ 、Ｃ_３ Ｈ_６ 、Ｃ_３ Ｈ_５ ＯＨ；Ｒ^５ ，Ｒ^６ ，Ｒ^７ ，Ｒ^８ はＨまたはＣＨ_３ 、Ｘ⁻ は対イオンを表す。）
【００１９】
本発明に用いられる高分子電解質から成る分散剤としては、５０〜１００モル％のジメチルアミノエチル（メタ）アクリレートの塩酸塩または硫酸塩、（メタ）アクリロイルオキシエチルトリメチルアンモニウムクロリド、ジメチルアミノプロピル（メタ）アクリルアミドの塩酸塩または硫酸塩、（メタ）アクリルアミドプロピルトリメチルアンモニウムクロリド、ジアリルアミンの塩酸塩または硫酸塩、ジメタリルアミンの塩酸塩または硫酸塩、ジメチルジアリルアンモニウムクロリドまたはそれらの混合物、の中から選ばれる少なくとも１種のカチオン性単量体、および５０〜０モル％のアクリルアミドを重合したカチオン性高分子電解質であることが好ましい。また、ポリアルキレンポリアミン等のポリアミンも使用することが出来る。
【００２０】
また、アニオン性重合体の分散液を得ようとする場合は、分散剤に（メタ）アクリル酸、アクリルアミド−２−メチルプロパンスルホン酸等の塩、またはこれらの混合物、の中から選ばれるアニオン性単量体の重合体あるいは共重合体を用いることも出来る。
【００２１】
本発明における分散剤である高分子電解質は、単量体を水性媒体に溶解し、窒素雰囲気下にて脱酸素状態の系で、重合開始剤、例えば２，２’−アゾビス（２−アミジノプロパン）２塩酸塩（Ｖ−５０と略す）あるいは２，２’−アゾビス［２−（２−イミダゾリン−２−イル）プロパン］２塩酸塩（ＶＡ−０４４と略す）のような水溶性アゾ系重合開始剤あるいは過硫酸アンモニウムおよび亜硫酸水素ナトリウム併用のような水溶性レドックス系重合開始剤を添加し、ラジカル重合を行うことにより所望の分散剤を得ることができる。重合の反応温度は０〜１００℃の範囲で重合開始剤の性質に応じて任意に選ぶ事ができる。分子量調節のため通常のラジカル重合に用いられるようなイソプロピルアルコールやメルカプタン等の連鎖移動剤を添加することも任意に選択することができる。分散剤である高分子電解質の重合は静置水溶液重合で行うのが通例ではあるが、製品の均質化の点からは撹拌下で重合を行うことが好ましい。
【００２２】
本発明において、水溶性重合体分散液の分散媒と成る塩水溶液は、原料である水溶性単量体と高分子電解質から成る分散剤の両者を溶解し、生成物である重合物の微細粒子を溶解しない塩水溶液である。そのため、本発明に於てはかかる性質を有する種類の塩をかかる性質を発揮する濃度の塩水溶液として使用する。
【００２３】
本発明に適した塩は硫酸塩の如き２価アニオン塩であり、対カチオンとしてはアンモニウムイオン、ナトリウムイオン、マグネシウムイオン、アルミニウムイオン等が選ばれる。具体的な塩としては、硫酸アンモニウム、硫酸水素アンモニウム、硫酸ナトリウム、硫酸水素ナトリウム、硫酸マグネシウム、硫酸水素マグネシウム、硫酸アルミニウム、硫酸水素アルミニウムである。特に硫酸アンモニウム、硫酸ナトリウムが本発明に適用される塩として好ましい。これら２価アニオン塩が上記の性質を有するためには、好ましくは塩濃度として１５重量％以上飽和濃度までの範囲が選ばれる。また塩化ナトリウム、塩化アンモニウムのような１価アニオン塩も上記２価アニオン塩と併用して用いることが出来る。
【００２４】
重合後に得られる水溶性重合体分散液に各種の塩を添加して分散液の流動性等を改善する方法が従来技術に述べた特許公報に記載されており、本技術は本発明に含まれる。
【００２５】
本発明は、前記重合体微粒子を得るにあたり、スルホン基を持った環式化合物あるいはその塩からなる増粘抑制剤を少なくとも１種添加することにより、重合中に反応液の粘度が大きく上昇する現象を抑制し、低パワーの撹拌機でも製造が出来、また、粗大粒子の生成を低減するものである。
【００２６】
本発明の増粘抑制剤は水溶性化合物であることが好ましく、分散媒である塩水溶液に溶解することがさらに好ましい。増粘抑制剤であるスルホン基を持った環式化合物あるいはその塩の中で水溶性の化合物を以下に具体的に挙げるが、具体例に限定されるものではない。
【００２７】
スルホン基を持った環式化合物およびその塩の具体例としては、２，４−ジメチルベンゼンスルホン酸、ｐ−トルエンスルホン酸、ベンゼンスルホン酸、ナフタレン−１，５−ジスルホン酸、１−ナフトール−３，６−ジスルホン酸、ナフタレン−１，３，６−トリスルホン酸およびその塩が挙げられる。
【００２８】
これらスルホン基を持った環式化合物およびその塩からなる増粘抑制剤は、反応液の重量に対して１０ｐｐｍから１００００ｐｐｍの範囲で添加されることが好ましい。１０ｐｐｍ以下では効果が無く１００００ｐｐｍ以上は経済的に無駄である。
【００２９】
上記の具体的に挙げた増粘抑制剤としての水溶性有機化合物は、それぞれ独立に使用しても良く又複数種を併用しても良い。
【００３０】
これらの化合物が反応系の増粘を抑制する作用は理論的に解明されていない。しかし、カチオン性水溶性重合体分散液の場合には、重合体のアミノ基の対イオンとしてスルホン基を持った環式化合物が働き、重合体の微細粒子の析出を促進させることにより増粘が抑制され、反応装置回転軸にかかるトルクが低下し、撹拌不良に伴い発生する粗大粒子の発生を軽減させるものと推測される。
【００３１】
本発明における水溶性重合体の分散液を得るためには、単量体、分散剤、増粘抑制剤を塩水溶液に溶解し、窒素雰囲気下にて脱酸素状態で、重合開始剤、例えばＶ−５０あるいはＶＡ−０４４のような水溶性アゾ系重合開始剤、あるいは過硫酸アンモニウムおよび亜硫酸水素ナトリウム併用のような水溶性レドックス系重合開始剤を添加し、撹拌下ラジカル重合を行う。重合の反応温度は０〜１００℃の範囲で重合開始剤の性質に応じて任意に選ぶ事ができる。分子量調節のため通常のラジカル重合に用いられるようなイソプロピルアルコールやメルカプタン等の連鎖移動剤を添加することも任意に選択することができる。重合体微細粒子の析出を円滑にするために周速１ｍ／分以上の撹拌を行う必要がある。装置から内容物が溢れない限り、撹拌速度の上限は無く、任意の撹拌条件を選ぶことができる。
【００３２】
単量体の供給方法としては、あらかじめ全量を反応装置に仕込む方法、一部をあらかじめ反応装置に仕込み残部を連続添加する方法、全量を連続添加する方法等、公知の任意の供給方法を採ることができる。
【００３３】
【実施例】
次に実施例によって、本発明を具体的に説明するが、本発明はその要旨を超えない限り、以下の実施例に制約されるものではない。
【００３４】
（実施例−１〜７）
撹拌機、窒素曝気管、温度制御装置およびリボンペラ（直径６５ｃｍ，回転数６０ｒｐｍ）を備えた反応槽（内径７０ｃｍ，容量２７０リットル）に、表１記載の組成ならびに濃度の単量体および表１記載の増粘抑制剤を表１記載量、分散剤としてポリジメチルジアリルアンモニウムクロリド１部（ＣＰＳ社製、商品名エージフロック−ＷＴ４０ＨＶ）ならびにポリメタクリロイルオキシエチルトリメチルアンモニウムクロリド（固有粘度２ｄｌ／ｇ）１部を仕込み、表１記載の単量体濃度、硫酸アンモニウム濃度になるように脱イオン水および硫酸アンモニウムを加え全体が均一になるように撹拌して溶解した。その後、５重量％のＶ−５０水溶液を重合開始剤として対モノマーあたり１００ｐｐｍ添加し、撹拌下、４８℃で１０時間重合した。その結果、塩水溶液に分散した粒径１０〜２０μｍの微粒子の重合体分散液が得られた。
【００３５】
重合反応中に攪拌機の回転軸にかかった最大のトルク値を表１に示す。また得られた重合体分散液を４０メッシュのステンレス標準篩で濾過し、篩上に残った重合体（粗大粒子）量を秤量した結果を表１に示す。
【００３６】
（比較例−１〜５）
増粘抑制剤を添加しない以外は合成例−１〜７と同様の操作を行い、重合反応中に攪拌機の回転軸にかかった最大のトルク値および粗大粒子量を秤量した結果を表１に示す。
【００３７】
【表１】

【００３８】
表中の各略号は下記のものを意味する。
ＤＭＡＢＣ：アクリロイルオキシエチルジメチルベンジルアンモニウムクロリドＤＭＱ ：アクリロイルオキシエチルトリメチルアンモニウムクロリド
ＡＡＭ ：アクリルアミド
ＡＡＣ ：アクリル酸
Ｂ１：２，４−ジメチルベンゼンスルホン酸ナトリウム
Ｂ２：ｐ−トルエンスルホン酸ナトリウム
Ｂ３：ベンゼンスルホン酸ナトリウム
Ｂ４：ナフタレン−１，５−ジスルホン酸二ナトリウム
Ｂ５：１−ナフトール−３，６−ジスルホン酸二ナトリウム
Ｂ６：ナフタレン−１，３，６−トリスルホン酸三ナトリウム
【００３９】
【発明の効果】
従来例である比較合成例に対し、増粘抑制剤であるスルホン基を持った環式化合物およびその塩を添加した本発明による合成例は各例において最大トルク値および粗大粒子量は顕著に減少する。すなわち本発明は装置の設計および運転上のメリットならびに得られた水溶性重合体分散液の品質上のメリットを有し、その経済的効果は大きい。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an aqueous salt solution of a water-soluble polymer widely used as a flocculant as a water treatment agent, a dehydrating agent, a papermaking agent used in a papermaking process, a dispersion stabilizer for various suspension solutions, a soil conditioner, and the like. The present invention relates to a method for producing a dispersion liquid having a low viscosity and high fluidity as a dispersion medium, and more specifically, it is characterized by adding a specific chemical substance and polymerizing in order to keep the viscosity of the reaction liquid at the time of polymerization low. It relates to a method for producing a water-soluble polymer dispersion.
[0002]
[Prior art]
Conventionally, as a method for producing a dispersion of fine water-soluble polymer particles having a low viscosity and a high fluidity using a salt aqueous solution as a dispersion medium, a method of polymerizing while stirring in the presence of a dispersant such as a polymer electrolyte Are disclosed in Japanese Patent Laid-Open Nos. 61-123610, 62-20502, 62-20511, and 2-105809.
[0003]
[Problems to be solved by the invention]
When the method disclosed in the above-mentioned patent publication is carried out, there is a phenomenon that the viscosity of the reaction solution is remarkably increased during the polymerization. For this reason, a large load is applied to the stirrer, a high-power motor and a stirring blade that can withstand high torque are required, and the cost of the reaction apparatus is increased. Moreover, since the reaction solution has a high viscosity, there is a problem that a poorly stirred portion is generated and coarse particles are generated.
[0004]
[Means for Solving the Problems]
As a result of various studies on methods for solving the above problems, the present inventors have found that by adding a specific compound to the reaction solution, an increase in the viscosity of the reaction solution during polymerization is suppressed, and the present invention has been achieved.
That is, the present invention relates to a water-soluble monomer having a double bond, a dispersant comprising a polymer electrolyte soluble in an aqueous salt solution in which the monomer is dissolved but the produced polymer is not dissolved. In the method for producing a water-soluble polymer dispersion liquid, which is polymerized with stirring in the presence of water to obtain fine polymer particles dispersed in an aqueous salt solution, a thickening inhibitor comprising a cyclic compound having a sulfonic group or a salt thereof By adding at least one of these, the phenomenon that the viscosity of the reaction solution increases greatly during polymerization can be suppressed, production can be performed with a low-power stirrer, and the production of coarse particles is reduced.
[0005]
In the above method, the water-soluble monomer having a double bond is represented by 0 to 30 mol% acrylic acid, 0 to 100 mol% acrylamide and 0 to 100 mol% of the following formula 1 and / or the following formula 2. It is preferable to consist of a cationic monomer.
[0006]
[Chemical 3]

(In the formula, A is O or NH; B is C ₂ H ₄ , C ₃ H ₆ , C ₃ H ₅ OH; R ¹ is H or CH ₃ ; R ² and R ³ are each having 1 to 4 carbon atoms. An alkyl group; R ⁴ represents hydrogen, an alkyl group having 1 to 4 carbon atoms, or a benzyl group; X ⁻ represents a counter ion.)
[0007]
[Formula 4]

(Wherein, A is O or NH; B is C ₂ H ₄ , C ₃ H ₆ , C ₃ H ₅ OH; R ⁵ , R ⁶ , R ⁷ , R ⁸ is H or CH ₃ , X ⁻ is (Represents a counter ion.)
[0008]
In the present invention, the dispersant is 50 to 100 mol% of dimethylaminoethyl (meth) acrylate salt, dimethylaminopropyl (meth) acrylamide salt, di (meth) allylamine salt, (meth) acryloyloxyethyltrimethylammonium salt. Cationic polymer obtained by polymerizing at least one cationic monomer selected from chloride, (meth) acrylamidopropyltrimethylammonium chloride, dimethyldiallylammonium chloride or a mixture thereof, and 50 to 0 mol% of acrylamide An electrolyte is preferred.
[0009]
Furthermore, in the present invention, in the above method, the salt forming the aqueous salt solution is preferably a divalent anion salt.
[0010]
Examples of the cyclic compound having a sulfone group and salts thereof include 2,4-dimethylbenzenesulfonic acid, p-toluenesulfonic acid, benzenesulfonic acid, naphthalene-1,5-disulfonic acid, and 1-naphthol-3. , 6-disulfonic acid, naphthalene-1,3,6-trisulfonic acid, and salts thereof are preferable.
[0011]
Furthermore, the addition amount of the thickening inhibitor is preferably 10 ppm to 10,000 ppm with respect to the weight of the reaction solution.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
In the present invention, a water-soluble monomer having a double bond is dissolved in an aqueous salt solution that dissolves the monomer but does not dissolve the produced polymer. In the method for producing a water-soluble polymer dispersion, which is polymerized with stirring under the coexistence to obtain fine polymer particles dispersed in an aqueous salt solution, at least one cyclic compound having a sulfone group or a salt thereof is increased. It is a method for producing a water-soluble polymer dispersion, which is added as a viscosity inhibitor.
[0013]
The water-soluble monomer having a double bond used in the present invention includes an amine salt of dialkylaminoalkyl (meth) acrylate and a quaternized product thereof, an amine salt of dialkylaminoalkyl (meth) acrylamide and a quaternized product thereof, dialkyl Cationic monomers such as amine salts of aminohydroxypropyl (meth) acrylate and quaternized compounds thereof, amine salts of dialkylaminohydroxypropyl (meth) acrylamide and quaternized compounds thereof, diallylamine salts and quaternized compounds thereof (meta ) Nonionic monomers such as acrylamide, N-vinylcarboxylic amide, acrylonitrile, vinyl acetate, anionic monomers such as (meth) acrylic acid, acrylamide-2-methylpropanesulfonic acid, itaconic acid, and mixtures thereof Is appropriately selected.
[0014]
Specific examples of these water-soluble monomers having a double bond include dimethylaminoethyl (meth) acrylate hydrochloride or sulfate, (meth) acryloyloxyethyltrimethylammonium chloride, (meth ) Acrylyloxyethyl dimethylbenzylammonium chloride, dimethylaminopropyl (meth) acrylamide hydrochloride or sulfate, (meth) acrylamidepropyltrimethylammonium chloride, (meth) acrylamidepropyldimethylbenzylammonium chloride, dimethylaminohydroxypropyl (meth) acrylate Hydrochloric acid or sulfate, (meth) acryloyloxyhydroxypropyltrimethylammonium chloride, (meth) acryloyloxyhydroxypropyldi Tilbenzylammonium chloride, diallyldimethylammonium chloride, (meth) acrylamide, N-vinylformamide, N-vinylacetamide, hydroxy (meth) acrylate as nonionic monomer, (meth) acrylic acid as anionic monomer , Acrylamide-2-methylpropanesulfonic acid, itaconic acid and the like, but are not limited thereto. Also, hydrophobic monomers such as acrylonitrile, vinyl acetate, and styrene can be copolymerized as long as the polymer remains water-soluble.
[0015]
The polymer forming the water-soluble polymer dispersion of the present invention is a polymer of the above-mentioned monomer, and particularly useful polymers are a polymer of only a cationic monomer, or a cationic monomer and acrylamide. Cationic polymers such as copolymers with nonionic monomers, amphoteric polymers that are copolymers of cationic monomers with nonionic monomers such as acrylamide and anionic monomers such as acrylic acid, and It is a nonionic polymer which is a homopolymer of a nonionic monomer such as acrylamide.
[0016]
Therefore, the more preferable water-soluble monomer having a double bond used in the present invention is 0 to 50 mol% of acrylic acid, 0 to 100 mol% of acrylamide and 0 to 100 mol% of the following formula 1 and / or It is a cationic monomer represented by Formula 2.
[0017]
[Chemical formula 5]

(In the formula, A is O or NH; B is C ₂ H ₄ , C ₃ H ₆ , C ₃ H ₅ OH; R ¹ is H or CH ₃ ; R ² and R ³ are each having 1 to 4 carbon atoms. An alkyl group; R ⁴ represents hydrogen, an alkyl group having 1 to 4 carbon atoms, or a benzyl group; X ⁻ represents a counter ion.)
[0018]
[Chemical 6]

(Wherein, A is O or NH; B is C ₂ H ₄ , C ₃ H ₆ , C ₃ H ₅ OH; R ⁵ , R ⁶ , R ⁷ , R ⁸ is H or CH ₃ , X ⁻ is (Represents a counter ion.)
[0019]
Examples of the dispersant comprising the polymer electrolyte used in the present invention include 50 to 100 mol% of dimethylaminoethyl (meth) acrylate hydrochloride or sulfate, (meth) acryloyloxyethyltrimethylammonium chloride, dimethylaminopropyl (meta ) At least one selected from acrylamide hydrochloride or sulfate, (meth) acrylamidopropyltrimethylammonium chloride, diallylamine hydrochloride or sulfate, dimethallylamine hydrochloride or sulfate, dimethyldiallylammonium chloride or mixtures thereof A cationic polyelectrolyte obtained by polymerizing a seed cationic monomer and 50 to 0 mol% of acrylamide is preferable. Polyamines such as polyalkylene polyamines can also be used.
[0020]
In addition, when trying to obtain a dispersion of an anionic polymer, an anionic property selected from (meth) acrylic acid, a salt of acrylamide-2-methylpropanesulfonic acid, or a mixture thereof as a dispersant. Monomer polymers or copolymers can also be used.
[0021]
The polymer electrolyte as a dispersant in the present invention is a system in which a monomer is dissolved in an aqueous medium and deoxygenated in a nitrogen atmosphere, and a polymerization initiator such as 2,2′-azobis (2-amidinopropane). ) Water-soluble azo polymerization such as dihydrochloride (abbreviated as V-50) or 2,2′-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride (abbreviated as VA-044) A desired dispersant can be obtained by adding a water-soluble redox polymerization initiator such as an initiator or a combination of ammonium persulfate and sodium bisulfite and performing radical polymerization. The polymerization reaction temperature can be arbitrarily selected in the range of 0 to 100 ° C. according to the properties of the polymerization initiator. The addition of a chain transfer agent such as isopropyl alcohol or mercaptan, which is used for normal radical polymerization for molecular weight adjustment, can also be arbitrarily selected. Polymerization of the polymer electrolyte as the dispersant is usually carried out by standing aqueous solution polymerization, but from the viewpoint of homogenization of the product, the polymerization is preferably carried out with stirring.
[0022]
In the present invention, the aqueous salt solution serving as a dispersion medium for the water-soluble polymer dispersion dissolves both the water-soluble monomer as the raw material and the dispersant composed of the polymer electrolyte, and produces fine particles of the polymer as the product. Is an aqueous salt solution that does not dissolve. Therefore, in the present invention, a salt having such a property is used as an aqueous salt solution having a concentration that exhibits such a property.
[0023]
Salts suitable for the present invention are divalent anion salts such as sulfates, and ammonium ions, sodium ions, magnesium ions, aluminum ions, etc. are selected as counter cations. Specific examples of the salt include ammonium sulfate, ammonium hydrogen sulfate, sodium sulfate, sodium hydrogen sulfate, magnesium sulfate, magnesium hydrogen sulfate, aluminum sulfate, and aluminum hydrogen sulfate. In particular, ammonium sulfate and sodium sulfate are preferable as the salt applied to the present invention. In order for these divalent anion salts to have the above properties, the salt concentration is preferably selected in the range of 15% by weight or more to the saturation concentration. Monovalent anion salts such as sodium chloride and ammonium chloride can also be used in combination with the divalent anion salt.
[0024]
A method of adding various salts to a water-soluble polymer dispersion obtained after polymerization to improve the fluidity of the dispersion is described in the patent publications mentioned in the prior art, and this technique is included in the present invention. .
[0025]
The present invention provides a phenomenon in which the viscosity of a reaction solution is greatly increased during polymerization by adding at least one thickening inhibitor comprising a cyclic compound having a sulfone group or a salt thereof in obtaining the polymer fine particles. Can be produced even with a low-power stirrer, and the production of coarse particles is reduced.
[0026]
The thickening inhibitor of the present invention is preferably a water-soluble compound, and more preferably dissolved in an aqueous salt solution that is a dispersion medium. Specific examples of water-soluble compounds among cyclic compounds having a sulfone group as a thickening inhibitor or salts thereof are not limited to the specific examples.
[0027]
Specific examples of the cyclic compound having a sulfone group and a salt thereof include 2,4-dimethylbenzenesulfonic acid, p-toluenesulfonic acid, benzenesulfonic acid, naphthalene-1,5-disulfonic acid, and 1-naphthol-3. , 6-disulfonic acid, naphthalene-1,3,6-trisulfonic acid and salts thereof.
[0028]
The thickening inhibitor comprising a cyclic compound having a sulfone group and a salt thereof is preferably added in the range of 10 ppm to 10,000 ppm with respect to the weight of the reaction solution. Below 10 ppm, there is no effect and above 10,000 ppm is economically wasteful.
[0029]
The water-soluble organic compounds as the thickening inhibitors specifically mentioned above may be used independently or in combination of two or more.
[0030]
The action of these compounds to suppress thickening of the reaction system has not been theoretically elucidated. However, in the case of a cationic water-soluble polymer dispersion, a cyclic compound having a sulfone group acts as a counter ion for the amino group of the polymer, and the viscosity is increased by promoting the precipitation of fine particles of the polymer. It is presumed that the torque applied to the reaction apparatus rotating shaft is reduced and the generation of coarse particles due to poor stirring is reduced.
[0031]
In order to obtain a dispersion of the water-soluble polymer in the present invention, a monomer, a dispersant, and a thickening inhibitor are dissolved in an aqueous salt solution and deoxidized in a nitrogen atmosphere, and a polymerization initiator such as V A water-soluble azo polymerization initiator such as -50 or VA-044, or a water-soluble redox polymerization initiator such as ammonium persulfate and sodium hydrogen sulfite in combination is added, and radical polymerization is performed with stirring. The polymerization reaction temperature can be arbitrarily selected in the range of 0 to 100 ° C. according to the properties of the polymerization initiator. The addition of a chain transfer agent such as isopropyl alcohol or mercaptan, which is used for normal radical polymerization for molecular weight adjustment, can also be arbitrarily selected. In order to facilitate the precipitation of polymer fine particles, it is necessary to perform stirring at a peripheral speed of 1 m / min or more. As long as the contents do not overflow from the apparatus, there is no upper limit of the stirring speed, and arbitrary stirring conditions can be selected.
[0032]
As the monomer supply method, a known arbitrary supply method such as a method in which the entire amount is charged in the reactor in advance, a method in which a part is charged in the reactor in advance and the remainder is continuously added, a method in which the entire amount is continuously added, etc. is adopted. Can do.
[0033]
【Example】
EXAMPLES Next, although an Example demonstrates this invention concretely, this invention is not restrict | limited to a following example, unless the summary is exceeded.
[0034]
(Examples-1 to 7)
In a reaction vessel (inner diameter 70 cm, capacity 270 liters) equipped with a stirrer, nitrogen aeration tube, temperature control device and ribbon peller (diameter 65 cm, rotation speed 60 rpm), monomers and compositions described in Table 1 1 part of polydimethyldiallylammonium chloride (manufactured by CPS, trade name Age floc-WT40HV) and 1 part of polymethacryloyloxyethyltrimethylammonium chloride (intrinsic viscosity 2 dl / g) Were added, deionized water and ammonium sulfate were added so that the monomer concentration and ammonium sulfate concentration shown in Table 1 were obtained, and the whole was stirred and dissolved to be uniform. Thereafter, 5 ppm by weight of V-50 aqueous solution was added as a polymerization initiator at 100 ppm per monomer, and polymerization was carried out at 48 ° C. for 10 hours with stirring. As a result, a polymer dispersion of fine particles having a particle diameter of 10 to 20 μm dispersed in an aqueous salt solution was obtained.
[0035]
Table 1 shows the maximum torque applied to the rotating shaft of the stirrer during the polymerization reaction. Table 1 shows the results obtained by filtering the obtained polymer dispersion with a 40-mesh stainless steel standard sieve and weighing the amount of polymer (coarse particles) remaining on the sieve.
[0036]
(Comparative Examples-1 to 5)
Table 1 shows the results of weighing the maximum torque value and the amount of coarse particles applied to the rotating shaft of the stirrer during the polymerization reaction by performing the same operations as in Synthesis Examples-1 to 7 except that no thickening inhibitor was added. .
[0037]
[Table 1]

[0038]
Each abbreviation in the table means the following.
DMABC: acryloyloxyethyldimethylbenzylammonium chloride DMQ: acryloyloxyethyltrimethylammonium chloride AAM: acrylamide AAC: acrylic acid B1: 2,4-dimethylbenzenesulfonic acid sodium salt B2: p-toluenesulfonic acid sodium salt B3: benzenesulfonic acid sodium salt B4 : Disodium naphthalene-1,5-disulfonate B5: disodium 1-naphthol-3,6-disulfonate B6: trisodium naphthalene-1,3,6-trisulfonate
【The invention's effect】
Compared to the comparative synthesis example, which is a conventional example, the synthesis examples according to the present invention to which a cyclic compound having a sulfone group as a thickening inhibitor and a salt thereof are added are markedly reduced in the maximum torque value and the amount of coarse particles in each example. To do. That is, the present invention has merits on the design and operation of the apparatus and the quality of the obtained water-soluble polymer dispersion, and its economic effect is great.

Claims (6)

A water-soluble monomer having a double bond is dissolved in an aqueous salt solution that dissolves the monomer but does not dissolve the produced polymer, in the presence of a dispersant composed of a polymer electrolyte that is soluble in the aqueous salt solution. In a method for producing a water-soluble polymer dispersion, which is polymerized with stirring to obtain fine polymer particles dispersed in an aqueous salt solution, at least one thickening inhibitor comprising a cyclic compound having a sulfone group or a salt thereof is used. A method for producing a water-soluble polymer dispersion, characterized by comprising: The water-soluble monomer having a double bond is 0 to 30 mol% acrylic acid, 0 to 100 mol% acrylamide and 0 to 100 mol% of a cationic monomer represented by the following formula 1 and / or formula 2 The method for producing a water-soluble polymer dispersion according to claim 1, comprising a body.

(In the formula, A is O or NH; B is C ₂ H ₄ , C ₃ H ₆ , C ₃ H ₅ OH; R ¹ is H or CH ₃ ; R ² and R ³ are each having 1 to 4 carbon atoms. An alkyl group; R ⁴ represents hydrogen, an alkyl group having 1 to 4 carbon atoms, or a benzyl group; X ⁻ represents a counter ion.)

(In the formula, A is O or NH; B is C ₂ H ₄ , C ₃ H ₆ , C ₃ H ₅ OH; R ⁵ , R ⁶ , R ⁷ , R ⁸ is H or CH ₃ , X ⁻ is Represents a counter ion.) The dispersant is 50 to 100 mol% of dimethylaminoethyl (meth) acrylate salt, dimethylaminopropyl (meth) acrylamide salt, di (meth) allylamine salt, (meth) acryloyloxyethyltrimethylammonium chloride, (meth) acrylamide. It is a cationic polyelectrolyte obtained by polymerizing at least one cationic monomer selected from propyltrimethylammonium chloride, dimethyldiallylammonium chloride or a mixture thereof, and 50 to 0 mol% of acrylamide. A method for producing a water-soluble polymer dispersion according to claim 1 or 2. 4. The method for producing a water-soluble polymer dispersion according to claim 1, wherein the salt forming the aqueous salt solution is a divalent anion salt. Cyclic compounds having a sulfone group and salts thereof are 2,4-dimethylbenzenesulfonic acid, p-toluenesulfonic acid, benzenesulfonic acid, naphthalene-1,5-disulfonic acid, 1-naphthol-3,6-disulfone. The method for producing a water-soluble polymer dispersion according to any one of claims 1 to 4, which is an acid, naphthalene-1,3,6-trisulfonic acid, or a salt thereof. The method for producing a water-soluble polymer dispersion according to any one of claims 1 to 5, wherein the addition amount of the thickening inhibitor is 10 ppm to 10,000 ppm with respect to the weight of the reaction solution.