JP3552407B2 - Method for producing vinyl chloride polymer - Google Patents
Method for producing vinyl chloride polymer Download PDFInfo
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- JP3552407B2 JP3552407B2 JP15832196A JP15832196A JP3552407B2 JP 3552407 B2 JP3552407 B2 JP 3552407B2 JP 15832196 A JP15832196 A JP 15832196A JP 15832196 A JP15832196 A JP 15832196A JP 3552407 B2 JP3552407 B2 JP 3552407B2
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- vinyl chloride
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Description
【0001】
【発明の属する技術分野】
本発明は、個数基準の粒径分布において、3個の極大値を有する塩化ビニル系重合体ラテックスの製造法に関するものである。
本発明で得られる塩化ビニル系重合体ラテックスは、乾燥した際に充填密度が高い重合体を与え、またこれに可塑剤等を配合すると流動性の良いプラスチゾルを与える。特に本発明によれば、ペースト用に好適な塩化ビニル系重合体を与えることのできる塩化ビニル系重合体ラテックスを容易に製造することができる。
【0002】
【従来の技術】
ペースト用塩化ビニル系重合体に可塑剤等を配合したプラスチゾルは、塗布、浸漬、スプレーその他の加工法により、床材や壁紙などの製造、自動車の防錆塗装(アンダーコート)など、種々の用途に供されている。床材、壁紙の製造に際しては、このプラスチゾルをナイフコーティング等の方法で基材上に塗布する方法が広く用いられており、生産性の向上のためプラスチゾルの粘度、特に102 sec−1以上のいわゆる高せん断速度領域での粘度を低くすることが望まれている。また、自動車のアンダーコートにはスプレー塗装法が多用されているが、この場合にも、噴霧の安定化のため、高せん断速度領域での低粘度化が求められている。
【0003】
【発明が解決しようとする課題】
プラスチゾルの流動性を良くする手法の一つとして、個数基準の粒径分布において複数の極大値を有する塩化ビニル系重合体を用いることが提案されている。例えば特公昭61−8843号公報には、粒径分布に2つの極大値を有する塩化ビニル系重合体ラテックスを混合して噴霧乾燥することが開示されている。しかし、この方法で得られた塩化ビニル系重合体に可塑剤を配合して得られるプラスチゾルは、高せん断速度領域の粘度が十分に低下しないという難点がある。また、特開平7−53627号公報には、異なる製法で得られた塩化ビニル系重合体ラテックスを混合して、粒径分布に3〜6個の極大値を有する塩化ビニル系重合体ラテックスを製造することが開示されている。更に特開平5−155908号公報には、複数の塩化ビニル系重合体ラテックスを混合して、粒径分布に複数の極大値のあるシードラテックスとし、このシードラテックスの存在下に塩化ビニル系単量体を重合することにより、複数の極大値を有する塩化ビニル系重合体ラテックスを製造することが記載されている。
【0004】
しかし、これらの方法で採用されている複数のラテックスを混合する方法は、操作が煩雑であり、またラテックスの安定性を維持するのが困難であるという難点がある。従って本発明は、個数基準の粒径分布に3つの極大値を有する塩化ビニル系重合体ラテックスを容易に製造する方法を提供せんとするものである。
【0005】
【課題を解決するための手段】
本発明によれば、先ず塩化ビニル系単量体(本明細書において塩化ビニル系単量体とは、塩化ビニル又は塩化ビニル及びこれと共重合し得る他の単量体との混合物を意味する。混合物に占める塩化ビニルの割合は通常は80重量%以上である)を乳化重合又は微細懸濁重合させて、塩化ビニル系重合体ラテックスを製造し、次いでこれをシードラテックスとして塩化ビニル系単量体を乳化重合又は微細懸濁重合して第2の塩化ビニル系重合体ラテックスを製造し、更にこれをシードラテックスとして再度塩化ビニル系単量体を乳化重合又は微細懸濁重合することにより、個数基準の粒径分布において3個の極大値を有する塩化ビニル系重合体ラテックスを製造することができる。
【0006】
【発明の実施の形態】
本発明について詳細に説明すると、本発明では塩化ビニル系単量体、すなわち塩化ビニル又は塩化ビニル及びこれと共重合可能な他の単量体との混合物を原料として、粒径分布に3個の極大値を有する塩化ビニル系重合体を製造する。共重合可能な他の単量体としては、酢酸ビニル、プロピオン酸ビニル、ステアリン酸ビニル等のビニルエステル類、メチルビニルエーテル、エチルビニルエーテル、オクチルビニルエーテル、ラウリルビニルエーテル等のビニルエーテル類、アクリル酸、メタクリル酸、イタコン酸などの不飽和カルボン酸やそアルキルエステル類、塩化ビニリデン、不飽和ニトリル等が挙げられる。重合に供する混合物は、これらの2種以上を含んでいてもよい。
【0007】
本発明では、先ず工程(I)として、塩化ビニル系単量体を常法により乳化重合又は微細懸濁重合して、個数基準の粒径分布に1個の極大値を有する重合体ラテックスを製造する。乳化重合は、乳化剤を含む水性媒体中で、水溶性重合開始剤を用いて行なえばよい。また微細懸濁重合は、塩化ビニル系単量体を、乳化剤の存在下、ホモジナイザーを用いて微細液滴状に分散させ、油溶性重合開始剤を用いて行なえばよい。乳化剤としては、高級アルコール硫酸エステル、アルキルベンゼンスルホン酸、高級脂肪酸などの、アルカリ金属塩やアンモニウム塩などが用いられる。また、アニオン系界面活性剤を用いることもできる。これらの界面活性剤は2種以上を併用することもでき、またこれらにノニオン系界面活性剤を併用することもできる。
【0008】
これらの乳化剤は、塩化ビニル系単量体に対し、通常、0.1〜3重量%、好ましくは0.3〜1重量%となるように使用する。
また、乳化助剤として、炭素数10〜18の高級アルコールを、0.2〜2重量%併用するのも好ましい。
重合開始剤としては、乳化重合の場合は、例えば過硫酸のナトリウム塩、カリウム塩、アンモニウム塩や過酸化水素等の水溶性過酸化物、またはこれらの水溶性過酸化物と水溶性還元剤、例えば亜硫酸ナトリウム、ピロ亜硫酸ナトリウム、亜硫酸水素ナトリウム、アスコルビン酸、ナトリウムホルムアルデヒドスルホキシレート等とからなる水溶性レドックス重合開始剤などが用いられる。微細懸濁重合の場合は、アゾビスイソブチロニトリル、アゾビス−2,4−ジメチルバレロニトリル、ラウロイルパーオキサイド、t−ブチルペルオキシピバレート等の単量体に可溶性の油溶性重合開始剤、またはこれらの油溶性重合開始剤と前記の水溶性還元剤との組合せからなるレドックス重合開始剤が用いられる。
【0009】
これらの重合開始剤は、塩化ビニル系単量体に対し、0.01〜0.5重量%、特に0.01〜0.2重量%程度の量を用いるのが好ましい。
重合反応系には更に、重合度調整剤その他の助剤類を添加してもよい。
重合度調整剤としては、トリクロルエチレン、四塩化炭素、2−メルカプトエタノール、オクチルメルカプタン等の連鎖移動剤、フタル酸ジアリル、イソシアヌル酸トリアリル、エチレングリコールジアクリレート、トリメチロールプロパントリメタクリレートなどの架橋剤が用いられる。
【0010】
他の助剤類としては、例えばレドックス重合開始剤の活性化剤として作用する塩化第二銅、硫酸第一鉄、硝酸第二ニッケル等の水溶性遷移金属塩や燐酸一水素又は二水素アルカリ金属塩、フタル酸水素カリウム、炭酸水素ナトリウムなどのpH調整剤等が挙げられる。
乳化重合、微細懸濁重合のいずれであっても、重合度は通常40〜70℃程度であり、重合時間は通常4〜10時間程度である。
この重合反応により、個数基準の粒径分布において1個の極大値を有する塩化ビニル系重合体ラテックス、すなわち通常の乳化重合又は微細懸濁重合で生成する重合体ラテックスの粒径分布パターンと同じパターンのラテックスを生成させる。極大値は0.3〜0.6μmの粒径範囲にあるのが好ましく、また粒径分布はシャープであるのが好ましい。
【0011】
本発明では、次いで工程(II)として、上記で得られた重合体をシードとして、上記と同様にして塩化ビニル系単量体の乳化重合又は微細懸濁重合を行ない、粒径分布において2個の極大値を有する重合体ラテックスを製造する。反応の制御及び得られるラテックスの粒径の制御よりして、乳化重合法が好ましい。
通常は、上記で得られた重合体ラテックスを、乾燥することなくそのままシードとして用いる。用いる重合体ラテックスの量は、塩化ビニル系単量体とラテックス中の重合体との合計量に対し、通常は3〜6重量%、好ましくは3.5〜5重量%である。このシード重合の条件は、前記のシードを製造するための重合と同じ条件を採用することができる。即ち、重合温度は40〜70℃程度であり、重合時間は3〜9時間程度である。また乳化剤、重合開始剤やその他の助剤などもシードの製造に用いたものと同じものを用いることができる。
【0012】
好ましくは、乳化剤として、新たな重合体粒子の生成が少なく、且つ重合体粒子の凝集を抑制する作用のあるラウリル硫酸ナトリウムやアルキルベンゼンスルホン酸ナトリウムが用いられる。また、重合開始剤としては、過酸化水素その他の水溶性過酸化物が用いられる。これらの乳化剤や重合開始剤は、乳化重合の反応中に連続的に反応系に添加するのが好ましい。
【0013】
このシート重合においては、シードの肥大反応と新たな重合体粒子の生成反応とを併発させ、個数基準の粒径分布において2個の極大値を有する重合体ラテックスを生成させる。すなわち、このシード重合は、若しシードが存在しなかったならば1個の極大値を有するラテックス、好ましくは1個の極大値を有し、且つシャープな粒径分布を有するラテックスを与えるように行なわれる。2個の極大値は0.2〜0.5μmと0.7〜1.6μmの粒径範囲にあるのが好ましい。
【0014】
本発明では、更に工程(III)として、上記で得られた粒径分布に2個の極大値を有するラテックスをシードとして、上記と同様にして塩化ビニル系単量体の乳化重合又は微細懸濁重合を行ない、粒径分布に3個の極大値を有する重合体ラテックスを製造する。この場合にも、反応の制御及び得られるラテックスの粒径の制御の容易な点よりして、乳化重合を行なうのが好ましい。また、シードの重合体ラテックスは、乾燥することなくそのまま用いるのが好ましい。用いる重合体ラテックスの量は、塩化ビニル系単量体と重合体ラテックス中の重合体との合計量に対し、通常は4〜12重量%、好ましくは6〜10重量%である。
【0015】
このシード重合も、前記のシード重合と同じ条件で行なうことができる。重合温度は40〜70℃程度であり、重合時間は3〜8時間程度である。乳化剤、重合開始剤やその他の助剤なども、前記のシード重合に用いたものと同じものを用いることができる。このシード重合においても、ラウリル硫酸ナトリウムやアルキルベンゼンスルホン酸ナトリウムなどの乳化剤、及び過酸化水素その他の水溶性過酸化物などの重合開始剤を、重合反応中に連続的に反応系に添加するのが好ましい。このシード重合においても、シードの肥大反応と新たな重合体粒子の生成反応とが併発し、個数基準の粒径分布に3個の極大値を有する重合体ラテックスが生成する。すなわち、このシード重合も、若しシードが存在しなかったならば1個の極大値を有するラテックスを与えるように行なわれる。
【0016】
本発明で得られる塩化ビニル系重合体ラテックスの3個の極大値は、0.1〜0.4μm,0.6〜1.0μm及び1.0μmを超え2.0μmまでの粒径範囲にあるのが好ましい。
特に好ましい重合体ラテックスは、0.1〜0.4μm,0.6〜1.0μm及び1.0μmを超え2.0μmまでに極大値を有し、且つこれら3個の極大値の間にある2個の極小値のうち、粒径の小さい方の極小値よりも小さい粒子の重量が重合体全体の10〜50重量%、粒径の大きい極小値よりも大きい粒子の重量が重合体全体の30〜40重量%を占めるラテックスである。このような粒子組成を有するラテックスは、高せん断速度領域において低い粘度を示し、作業性のよいプラスチゾルを与える。
【0017】
本発明方法により製造された3個の極大値を有する塩化ビニル系重合体ラテックスは、常法により乾燥、粉砕等の製品化処理を施して製品の塩化ビニル系重合体とする。その際、必要に応じて、常用の調整用乳化剤、酸化防止剤その他の助剤、改質剤などを添加してもよい。また、このようにして得られた塩化ビニル系重合体は、可塑剤、有機溶剤、安定剤、充填剤、酸化防止剤、紫外線吸収剤、帯電防止剤、着色剤、離型剤などの配合剤を適宜配合して、プラスチゾル又はオルガノゾルとして用いられる。
なお、本発明において、塩化ビニル系重合体の粒径分布は、キャピラリー方式のサブミクロン粒度分布測定器であるMATEC APPLIED SCIENCES社製のCHDF−1100を用いて測定するものとする。
【0018】
【実施例】
以下に本発明を実施例を用いて更に具体的に説明するが、本発明はその要旨を越えない限り、以下の実施例によって限定されるものではない。なお、実施例中の「%」は特記する以外は「重量%」を表す。
実施例1
下記の工程(I)、(II)及び(III)を実施して、塩化ビニル系重合体ラテックスを得た。
【0019】
工程(I):
攪拌機を備えた容積300リットルの重合缶に、温度54℃の脱イオン水90kg、過硫酸カリウム10g、ピロ亜硫酸ナトリウム50g及び初期乳化剤としてラウリル硫酸ナトリウム22gを仕込み、脱気した後、約20分間攪拌して溶解させた。次いで重合缶に60kgの塩化ビニルを仕込み、攪拌して乳化させ、缶内温度を50℃に調節した。塩化ビニルの仕込み完了後15分経過してから、総量で10gの過硫酸カリウムを0.2%過硫酸カリウム水溶液として、重合反応速度が一定になるように制御しながら、重合終了時までかけて添加した。更に重合率が約15%に達した時に、10%ラウリル硫酸ナトリウム水溶液を約80ml/10分の速度で添加し、ラウリル硫酸ナトリウムの総添加量が360gになるまで添加を続けた。缶内圧力が50℃での塩化ビニルの飽和圧から1960hPa(2kg/cm2 )降下した時点で反応を停止し、未反応の塩化ビニルを回収して塩化ビニル系重合体ラテックスを得た。このラテックスは、粒径が0.35μmの位置に粒径分布の極大値を有するシャープな粒径分布を有する粒子からなり、安定性は良好であった。
【0020】
工程(II):
攪拌機を備えた容積300リットルの重合缶に、脱イオン水80kg及び上記の工程(I)で調製された塩化ビニル系重合体ラテックスを固形分量で3.0kgを仕込んだ後、脱気して塩化ビニル77.0kgを加え、乳化させた。缶内温度を55℃に昇温した後、過酸化水素−ナトリウムホルムアルデヒドスルホキシレートのレドックス重合開始剤を、全添加量が塩化ビニルに対し0.05%となるように連続的に添加した。更に重合率がシード重合体と塩化ビニルとの合計量に対して10%に達した時点から、総量で500gのラウリル硫酸ナトリウムを、塩化ビニルに対して毎時約0.08%の割合で10%水溶液として連続的に添加した。
【0021】
缶内圧力が55℃での塩化ビニルの飽和圧から980hPa(1kg/cm2 )低下した時点で反応を停止し、未反応の塩化ビニルを回収して塩化ビニル系重合体ラテックスを得た。ラテックス中の塩化ビニル系重合体の粒子組成は、粒径0.30μm及び0.95μmの2点で極大値を示し、かつその粒径分布曲線において2つのピークが独立した、いわゆる二山粒径分布を示した。極大値の間に存在する極小値よりも大きな粒子の重量は重合体重量の78%、極小値よりも小さな粒子の重量は22%であった。
【0022】
工程(III):
攪拌機を備えた容積300リットルの重合缶に、脱イオン水80kg及び上記の工程(II)で調製された塩化ビニル系重合体ラテックスを固形分量で8kg仕込んだ後、脱気して塩化ビニル72kgを加え乳化させた。缶内温度を55℃に昇温した後、過酸化水素−ナトリウムホルムアルデヒドスルホキシレートのレドックス重合開始剤を、全添加量が塩化ビニルに対し0.05%となるように連続的に添加した。更に重合率がシード重合体と塩化ビニルとの合計量に対して15%に達した時点から、総量で500gのラウリル硫酸ナトリウムを塩化ビニルに対して毎時約0.10%の割合で10%水溶液として連続的に添加した。
【0023】
缶内圧力が55℃での塩化ビニルの飽和圧から980hPa(1kg/cm2 )低下した時点で反応を停止し、未反応の塩化ビニルを回収して塩化ビニル系重合体ラテックスを得た。ラテックス中の塩化ビニル系重合体の粒子組成は、粒径0.13μm,0.65μm及び1.46μmの3点で極大値を示し、かつその粒径分布曲線において3つのピークが独立したいわゆる三山粒径分布を示した。0.65μmと1.46μmとの間の極小値よりも大きな粒子の重量は、全重合体の33%、0.13μmと0.65μmとの間の極小値よりも小さな粒子の重量は、全重合体の31%であった。
実施例2
下記の工程(I)、(II)及び(III)を実施して、塩化ビニル系重合体ラテックスを得た。
【0024】
工程(I):
攪拌機及び乳化機(マントンゴーリン式高圧ホモジナイザー)を備えた容積300リットルの予備混合槽に、脱イオン水75kg、ラウロイルパーオキサイド100g、ラウリル硫酸ナトリウム558g、ラウリルアルコール400gを添加し、次いで予備混合槽を脱気した後、塩化ビニル60kgを添加し、均一に攪拌しながら35℃に保持した。次いで乳化機を用いて1次圧14.8MPa,2次圧5.0MPaの条件で微細液滴に分散させながら、分散液を予め脱気しておいた攪拌機を備えた容積300リットルの重合缶に移送した。
分散液の移送終了後、重合缶の温度を55℃に昇温して、攪拌下に重合を開始した。缶内圧力が55℃での塩化ビニルの飽和圧から980hPa(1kg/cm2 )低下したところで反応を停止し、未反応の塩化ビニルを回収し、塩化ビニル系重合体ラテックスを得た。このラテックスは、0.48μmに極大値を有するシャープな粒径分布の重合体からなっていた。
【0025】
工程(II):
上記の工程(I)で得られた塩化ビニル重合体ラテックスを固形分量で4.0kg用い、かつ塩化ビニルの添加量を76kgに変更した以外は、実施例1の工程(II)と同様の方法でシード重合を行い、塩化ビニル系重合体ラテックスを得た。ラテックス中の塩化ビニル系重合体の粒子組成は、径0.35μm及び1.19μmの2点で極大値を示し、かつその粒径分布曲線において2つのピークが独立したいわゆる二山粒径分布を示した。2つの極大値の間に存在する極小値よりも大きな粒子の重量は重合体重量の70%、極小値よりも小さな粒子の重量は30%であった。
【0026】
工程(III):
攪拌機を備えた容積300リットルの重合缶に、脱イオン水80kg及び上記の工程(II)で調製された塩化ビニル系重合体ラテックスを固形分量で8kg仕込んだ後、脱気して塩化ビニル72kgを加え乳化させた。缶内温度を55℃に昇温した後、過酸化水素−ナトリウムホルムアルデヒドスルホキシレートのレドックス重合開始剤を、全添加量が塩化ビニルに対し0.05%となるように連続的に添加した。更に重合率がシード重合体と塩化ビニルとの合計量に対して15%に達した時点から、総量で500gのラウリル硫酸ナトリウムを塩化ビニルに対して毎時約0.10%の割合で10%水溶液として連続的に添加した。
【0027】
缶内圧力が55℃での塩化ビニルの飽和圧から980hPa(1kg/cm2 )低下した時点で反応を停止し、未反応の塩化ビニルを回収して塩化ビニル系重合体ラテックスを得た。ラテックス中の塩化ビニル系重合体の粒子組成は、径0.19μm,0.71μm及び1.68μmの3点で極大値を示し、かつその粒径分布曲線において3つのピークが独立したいわゆる三山粒径分布を示した。0.71μmと1.68μmとの間の極小値よりも大きい粒子の重量は全重合体の38%、0.19μmと0.71μmとの間の極小値よりも小さな粒子の重量は、全重合体の25%であった。
【0028】
【発明の効果】
本発明によれば、ラテックスの混合操作行わずに簡便に三山粒径分布ラテックスを製造できる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention, in the particle size distribution of number-based, relates to three preparation of vinyl chloride polymer latex having a maximum value.
The vinyl chloride-based polymer latex obtained in the present invention gives a polymer having a high packing density when dried, and a plastisol having good fluidity when a plasticizer or the like is added thereto. In particular, according to the present invention, a vinyl chloride polymer latex that can provide a vinyl chloride polymer suitable for a paste can be easily produced.
[0002]
[Prior art]
Plastisols containing plasticizers and the like in a vinyl chloride polymer for pastes are used for various purposes such as flooring and wallpaper production, rust-proof coating (undercoat) for automobiles by coating, dipping, spraying and other processing methods. It has been offered to. In the production of flooring and wallpaper, a method of applying this plastisol on a substrate by a method such as knife coating is widely used, and in order to improve productivity, the viscosity of the plastisol, particularly 10 2 sec −1 or more, is used. It is desired to lower the viscosity in a so-called high shear rate region. In addition, a spray coating method is frequently used for undercoating of automobiles. In this case, too, a low viscosity in a high shear rate region is required in order to stabilize the spray.
[0003]
[Problems to be solved by the invention]
As one of techniques for improving the fluidity of plastisol, it has been proposed to use a vinyl chloride polymer having a plurality of maximum values in a number-based particle size distribution. For example, Japanese Patent Publication No. 61-8843 discloses that a vinyl chloride polymer latex having two maximum values in particle size distribution is mixed and spray-dried. However, the plastisol obtained by blending a plasticizer with the vinyl chloride polymer obtained by this method has a drawback that the viscosity in the high shear rate region is not sufficiently reduced. JP-A-7-53627 discloses that a vinyl chloride polymer latex having a maximum value of 3 to 6 particles in a particle size distribution is produced by mixing vinyl chloride polymer latexes obtained by different production methods. Is disclosed. Further, JP-A-5-155908 discloses that a plurality of vinyl chloride-based polymer latexes are mixed to form a seed latex having a plurality of maximum values in particle size distribution, and a vinyl chloride-based monomer is added in the presence of the seed latex. It is described that a vinyl chloride polymer latex having a plurality of maximum values is produced by polymerizing a polymer.
[0004]
However, the method of mixing a plurality of latexes employed in these methods has the disadvantage that the operation is complicated and it is difficult to maintain the stability of the latex. Accordingly, the present invention is Ru der which provides cents a method for easily producing a vinyl chloride polymer latex having a three maxima in the particle size distribution of number basis.
[0005]
[Means for Solving the Problems]
According to the present invention, first, a vinyl chloride-based monomer (in the present specification, a vinyl chloride-based monomer means vinyl chloride or a mixture of vinyl chloride and another monomer copolymerizable therewith. The proportion of vinyl chloride in the mixture is usually 80% by weight or more) is subjected to emulsion polymerization or fine suspension polymerization to produce a vinyl chloride polymer latex, which is then used as a seed latex to obtain a vinyl chloride monomer. The emulsion is subjected to emulsion polymerization or fine suspension polymerization to produce a second vinyl chloride-based polymer latex, which is further used as a seed latex to again carry out emulsion polymerization or fine suspension polymerization of the vinyl chloride-based monomer to obtain a number. A vinyl chloride polymer latex having three maximum values in a standard particle size distribution can be produced.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention will be described in detail. In the present invention, a vinyl chloride monomer, that is, a mixture of vinyl chloride or vinyl chloride and another monomer copolymerizable therewith is used as a raw material, and three particles have a particle size distribution. A vinyl chloride polymer having a maximum value is produced. Other copolymerizable monomers include vinyl esters such as vinyl acetate, vinyl propionate and vinyl stearate, vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, octyl vinyl ether and lauryl vinyl ether, acrylic acid, methacrylic acid, Examples include unsaturated carboxylic acids such as itaconic acid and alkyl esters thereof, vinylidene chloride, unsaturated nitrile and the like. The mixture to be subjected to polymerization may contain two or more of these.
[0007]
In the present invention, first, in step (I), a vinyl chloride monomer is subjected to emulsion polymerization or fine suspension polymerization by a conventional method to produce a polymer latex having one maximum value in the number-based particle size distribution. I do. Emulsion polymerization may be performed in an aqueous medium containing an emulsifier using a water-soluble polymerization initiator. The fine suspension polymerization may be performed by dispersing a vinyl chloride monomer in the form of fine droplets using a homogenizer in the presence of an emulsifier, and using an oil-soluble polymerization initiator. As the emulsifier, an alkali metal salt or an ammonium salt such as a higher alcohol sulfate, an alkylbenzene sulfonic acid, or a higher fatty acid is used. Also, an anionic surfactant can be used. Two or more of these surfactants can be used in combination, and a nonionic surfactant can be used in combination with them.
[0008]
These emulsifiers are used in an amount of usually 0.1 to 3% by weight, preferably 0.3 to 1% by weight, based on the vinyl chloride monomer.
It is also preferable to use 0.2 to 2% by weight of a higher alcohol having 10 to 18 carbon atoms as an emulsifying aid.
As the polymerization initiator, in the case of emulsion polymerization, for example, water-soluble peroxides such as sodium salt, potassium salt, ammonium salt and hydrogen peroxide of persulfuric acid, or these water-soluble peroxides and water-soluble reducing agents, For example, a water-soluble redox polymerization initiator composed of sodium sulfite, sodium pyrosulfite, sodium bisulfite, ascorbic acid, sodium formaldehyde sulfoxylate, or the like is used. In the case of fine suspension polymerization, an oil-soluble polymerization initiator soluble in monomers such as azobisisobutyronitrile, azobis-2,4-dimethylvaleronitrile, lauroyl peroxide, t-butylperoxypivalate, or A redox polymerization initiator comprising a combination of these oil-soluble polymerization initiators and the above-mentioned water-soluble reducing agent is used.
[0009]
These polymerization initiators are preferably used in an amount of about 0.01 to 0.5% by weight, particularly about 0.01 to 0.2% by weight, based on the vinyl chloride-based monomer.
The polymerization reaction system may further include a polymerization degree regulator and other auxiliaries.
As the polymerization degree regulator, a chain transfer agent such as trichloroethylene, carbon tetrachloride, 2-mercaptoethanol, octyl mercaptan, a cross-linking agent such as diallyl phthalate, triallyl isocyanurate, ethylene glycol diacrylate, trimethylolpropane trimethacrylate, and the like. Used.
[0010]
Other auxiliary agents include, for example, water-soluble transition metal salts such as cupric chloride, ferrous sulfate, and nickel nitrate that act as activators for redox polymerization initiators, and monohydrogen phosphate or dihydrogen alkali metal. PH adjusters such as salts, potassium hydrogen phthalate and sodium hydrogen carbonate.
In either case of emulsion polymerization or fine suspension polymerization, the polymerization degree is usually about 40 to 70 ° C, and the polymerization time is usually about 4 to 10 hours.
By this polymerization reaction, the same pattern as the particle size distribution pattern of the vinyl chloride polymer latex having one local maximum in the number-based particle size distribution, that is, the polymer latex produced by ordinary emulsion polymerization or fine suspension polymerization. Of latex. The maximum value is preferably in a particle size range of 0.3 to 0.6 μm, and the particle size distribution is preferably sharp.
[0011]
In the present invention, as step (II), emulsion polymerization or fine suspension polymerization of a vinyl chloride monomer is carried out in the same manner as described above, using the polymer obtained above as a seed, and two particles in the particle size distribution are obtained. To produce a polymer latex having a maximum value of The emulsion polymerization method is preferred because of the control of the reaction and the control of the particle size of the obtained latex.
Usually, the polymer latex obtained above is used as a seed without drying. The amount of the polymer latex to be used is usually 3 to 6% by weight, preferably 3.5 to 5% by weight, based on the total amount of the vinyl chloride monomer and the polymer in the latex. The conditions for the seed polymerization may be the same as those for the polymerization for producing the seed. That is, the polymerization temperature is about 40 to 70 ° C., and the polymerization time is about 3 to 9 hours. The same emulsifier, polymerization initiator and other auxiliaries as those used in the production of the seed can be used.
[0012]
Preferably, as the emulsifier, sodium lauryl sulfate or sodium alkylbenzene sulfonate, which has a small amount of new polymer particles and has an action of suppressing aggregation of the polymer particles, is used. Further, as the polymerization initiator, hydrogen peroxide or other water-soluble peroxide is used. These emulsifiers and polymerization initiators are preferably added continuously to the reaction system during the emulsion polymerization reaction.
[0013]
In the sheet polymerization, a seed enlargement reaction and a new polymer particle formation reaction are caused simultaneously, and a polymer latex having two maximum values in a number-based particle size distribution is generated. That is, the seed polymerization is to provide a latex having one maximum, preferably one maximum, and a sharp particle size distribution if no seed is present. Done. The two maximum values are preferably in the particle size range of 0.2 to 0.5 μm and 0.7 to 1.6 μm.
[0014]
In the present invention, as a step (III), the latex having two maximum values in the particle size distribution obtained above is used as a seed, and emulsion polymerization or fine suspension of a vinyl chloride monomer is performed in the same manner as described above. The polymerization is carried out to produce a polymer latex having three maximum values in the particle size distribution. Also in this case, it is preferable to carry out emulsion polymerization from the viewpoint of easy control of the reaction and control of the particle size of the obtained latex. The seed polymer latex is preferably used as it is without drying. The amount of the polymer latex used is usually 4 to 12% by weight, preferably 6 to 10% by weight, based on the total amount of the vinyl chloride monomer and the polymer in the polymer latex.
[0015]
This seed polymerization can also be performed under the same conditions as the above-mentioned seed polymerization. The polymerization temperature is about 40 to 70 ° C., and the polymerization time is about 3 to 8 hours. The same emulsifier, polymerization initiator and other auxiliaries as those used in the above-mentioned seed polymerization can be used. Also in this seed polymerization, it is necessary to continuously add an emulsifier such as sodium lauryl sulfate and sodium alkylbenzene sulfonate, and a polymerization initiator such as hydrogen peroxide and other water-soluble peroxides to the reaction system during the polymerization reaction. preferable. Also in this seed polymerization, the seed enlargement reaction and the formation reaction of new polymer particles occur simultaneously, and a polymer latex having three maximum values in the number-based particle size distribution is generated. That is, the seed polymerization is also performed so as to provide a latex having one local maximum if no seed is present.
[0016]
The three maximum values of the vinyl chloride polymer latex obtained in the present invention are in the particle size range of 0.1 to 0.4 μm, 0.6 to 1.0 μm, and more than 1.0 μm to 2.0 μm. Is preferred.
Particularly preferred polymer latexes have maxima from 0.1 to 0.4 μm, 0.6 to 1.0 μm and more than 1.0 μm to 2.0 μm, and lie between these three maxima. Of the two minimum values, the weight of the particles smaller than the smaller minimum value of the particle size is 10 to 50% by weight of the entire polymer, and the weight of the particles larger than the minimum value of the larger particle size is the weight of the entire polymer. Latex accounts for 30 to 40% by weight. The latex having such a particle composition exhibits a low viscosity in a high shear rate region, and gives a plastisol with good workability.
[0017]
The vinyl chloride polymer latex having three maximum values produced by the method of the present invention is subjected to a commercialization process such as drying and pulverization by a conventional method to obtain a vinyl chloride polymer of the product. At that time, if necessary, a usual adjusting emulsifier, an antioxidant and other auxiliaries, a modifier, and the like may be added. Further, the vinyl chloride polymer thus obtained is used as a compounding agent such as a plasticizer, an organic solvent, a stabilizer, a filler, an antioxidant, an ultraviolet absorber, an antistatic agent, a colorant, and a release agent. Is appropriately blended and used as a plastisol or organosol.
In the present invention, the particle size distribution of the vinyl chloride polymer is measured using CHDF-1100 manufactured by MATEC APPLIED SCIENCES, which is a capillary type submicron particle size distribution analyzer.
[0018]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless departing from the gist of the invention. In the examples, "%" represents "% by weight" unless otherwise specified.
Example 1
The following steps (I), (II) and (III) were performed to obtain a vinyl chloride polymer latex.
[0019]
Step (I):
90 kg of deionized water at a temperature of 54 ° C., 10 g of potassium persulfate, 50 g of sodium pyrosulfite, and 22 g of sodium lauryl sulfate as an initial emulsifier were charged into a 300-liter polymerization vessel equipped with a stirrer, and stirred for about 20 minutes after deaeration. And dissolved. Next, 60 kg of vinyl chloride was charged into the polymerization can, stirred and emulsified, and the temperature in the can was adjusted to 50 ° C. Fifteen minutes after the completion of the charging of vinyl chloride, a total of 10 g of potassium persulfate was converted into a 0.2% aqueous solution of potassium persulfate while controlling the polymerization reaction rate to be constant. Was added. When the polymerization rate reached about 15%, a 10% aqueous solution of sodium lauryl sulfate was added at a rate of about 80 ml / 10 minutes, and the addition was continued until the total amount of sodium lauryl sulfate reached 360 g. The reaction was stopped when the pressure in the vessel dropped from the saturation pressure of vinyl chloride at 50 ° C. by 1960 hPa (2 kg / cm 2 ), and unreacted vinyl chloride was recovered to obtain a vinyl chloride polymer latex. This latex was composed of particles having a sharp particle size distribution having a maximum value of the particle size distribution at a position where the particle size was 0.35 μm, and the stability was good.
[0020]
Step (II):
80 kg of deionized water and 3.0 kg of the vinyl chloride polymer latex prepared in the above step (I) in a solid content of 3.0 kg were charged into a 300 l polymerization vessel equipped with a stirrer. 77.0 kg of vinyl was added and emulsified. After the temperature in the can was raised to 55 ° C., a redox polymerization initiator of hydrogen peroxide-sodium formaldehyde sulfoxylate was continuously added so that the total amount was 0.05% based on vinyl chloride. Further, when the polymerization rate reaches 10% with respect to the total amount of the seed polymer and vinyl chloride, a total of 500 g of sodium lauryl sulfate is added to vinyl chloride at a rate of about 0.08% per hour at 10%. It was added continuously as an aqueous solution.
[0021]
The reaction was stopped when the pressure in the can was lowered by 980 hPa (1 kg / cm 2 ) from the saturation pressure of vinyl chloride at 55 ° C., and unreacted vinyl chloride was recovered to obtain a vinyl chloride polymer latex. The particle composition of the vinyl chloride polymer in the latex shows a maximum value at two points of a particle diameter of 0.30 μm and 0.95 μm, and two peaks are independent in a particle diameter distribution curve, that is, a so-called two-peak particle diameter. The distribution was shown. The weight of particles larger than the minimum existing between the local maximums was 78% of the polymer weight, and the weight of particles smaller than the local minimum was 22%.
[0022]
Step (III):
80 kg of deionized water and 8 kg of a solid content of the vinyl chloride polymer latex prepared in the above step (II) were charged into a 300 liter polymerization vessel equipped with a stirrer, and then degassed to obtain 72 kg of vinyl chloride. It was emulsified by addition. After the temperature in the vessel was raised to 55 ° C., a redox polymerization initiator of hydrogen peroxide-sodium formaldehyde sulfoxylate was continuously added so that the total addition amount was 0.05% based on vinyl chloride. Further, when the polymerization rate reaches 15% with respect to the total amount of the seed polymer and vinyl chloride, a total of 500 g of sodium lauryl sulfate is added to a 10% aqueous solution at a rate of about 0.10% per hour to vinyl chloride. Was added continuously.
[0023]
The reaction was stopped when the pressure in the can was lowered by 980 hPa (1 kg / cm 2 ) from the saturation pressure of vinyl chloride at 55 ° C., and unreacted vinyl chloride was recovered to obtain a vinyl chloride polymer latex. The particle composition of the vinyl chloride polymer in the latex shows maximum values at three points of particle diameters of 0.13 μm, 0.65 μm and 1.46 μm, and three peaks are independent in the particle diameter distribution curve, so-called Miyama. The particle size distribution is shown. The weight of particles larger than the minimum between 0.65 μm and 1.46 μm is 33% of the total polymer, and the weight of particles smaller than the minimum between 0.13 μm and 0.65 μm is less than the total weight. It was 31% of the polymer.
Example 2
The following steps (I), (II) and (III) were performed to obtain a vinyl chloride polymer latex.
[0024]
Step (I):
75 kg of deionized water, 100 g of lauroyl peroxide, 558 g of sodium lauryl sulfate, and 400 g of lauryl alcohol are added to a 300-liter premixing tank equipped with a stirrer and an emulsifier (Manton-Gaulin high-pressure homogenizer). After degassing, 60 kg of vinyl chloride was added, and the mixture was maintained at 35 ° C. with uniform stirring. Then, while dispersing into fine droplets under the conditions of a primary pressure of 14.8 MPa and a secondary pressure of 5.0 MPa using an emulsifier, a 300-liter capacity polymerization vessel equipped with a stirrer in which the dispersion was previously degassed. Transferred to.
After the transfer of the dispersion was completed, the temperature of the polymerization vessel was raised to 55 ° C., and polymerization was started with stirring. The reaction was stopped when the pressure in the vessel dropped 980 hPa (1 kg / cm 2 ) from the saturation pressure of vinyl chloride at 55 ° C., and unreacted vinyl chloride was recovered to obtain a vinyl chloride polymer latex. This latex consisted of a polymer with a sharp particle size distribution having a maximum at 0.48 μm.
[0025]
Step (II):
A method similar to that of step (II) in Example 1 except that the vinyl chloride polymer latex obtained in the above step (I) was used in an amount of 4.0 kg in solid content and the amount of vinyl chloride added was changed to 76 kg. Was performed to obtain a vinyl chloride polymer latex. The particle composition of the vinyl chloride polymer in the latex shows a maximum value at two points of 0.35 μm and 1.19 μm in diameter, and a so-called two-peak particle size distribution in which two peaks are independent in the particle size distribution curve. Indicated. The weight of particles larger than the minimum existing between the two maximums was 70% of the polymer weight, and the weight of particles smaller than the minimum was 30%.
[0026]
Step (III):
80 kg of deionized water and 8 kg of the vinyl chloride-based polymer latex prepared in the above step (II) were charged in a solid content of 8 kg into a 300-liter polymerization can equipped with a stirrer, and then degassed to obtain 72 kg of vinyl chloride. It was emulsified by addition. After the temperature in the vessel was raised to 55 ° C., a redox polymerization initiator of hydrogen peroxide-sodium formaldehyde sulfoxylate was continuously added so that the total addition amount was 0.05% based on vinyl chloride. Further, when the polymerization rate reaches 15% with respect to the total amount of the seed polymer and vinyl chloride, a total of 500 g of sodium lauryl sulfate is added to a 10% aqueous solution at a rate of about 0.10% per hour with respect to vinyl chloride. Was added continuously.
[0027]
The reaction was stopped when the pressure in the can was lowered by 980 hPa (1 kg / cm 2 ) from the saturation pressure of vinyl chloride at 55 ° C., and unreacted vinyl chloride was recovered to obtain a vinyl chloride polymer latex. The particle composition of the vinyl chloride polymer in the latex shows so-called three-peak particles in which maximum values are shown at three points of diameters 0.19 μm, 0.71 μm and 1.68 μm, and three peaks are independent in the particle diameter distribution curve. The diameter distribution was shown. The weight of particles larger than the minimum between 0.71 μm and 1.68 μm is 38% of the total polymer, and the weight of particles smaller than the minimum between 0.19 μm and 0.71 μm is the total weight 25% of the coalescence.
[0028]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, a three-peak particle size distribution latex can be easily manufactured without performing the mixing operation of latex.
Claims (6)
工程(I);塩化ビニル系単量体を乳化重合又は微細懸濁重合させて、個数基準の粒径分布において1個の極大値を有する塩化ビニル系重合体を製造する。
工程(II);工程(I)で得られた塩化ビニル系重合体の存在下に塩化ビニル系単量体を乳化重合又は微細懸濁重合させて、個数基準の粒径分布において2個の極大値を有する塩化ビニル系重合体を製造する。
工程(III);工程(II)で得られた塩化ビニル系重合体の存在下に塩化ビニル系単量体を乳化重合又は微細懸濁重合させて、個数基準の粒径分布において3個の極大値を有する塩化ビニル系重合体を製造する。In a method for producing a vinyl chloride polymer latex by emulsion polymerization or fine suspension polymerization of a vinyl chloride monomer, the number is obtained by performing the following steps (I), (II) and (III). A method for producing a vinyl chloride polymer latex having three maximum values in a standard particle size distribution.
Step (I): Emulsion polymerization or fine suspension polymerization of a vinyl chloride monomer to produce a vinyl chloride polymer having one maximum value in a number-based particle size distribution.
Step (II): Emulsion polymerization or fine suspension polymerization of a vinyl chloride monomer in the presence of the vinyl chloride polymer obtained in Step (I) to obtain two peaks in the number-based particle size distribution. A vinyl chloride polymer having a specific value is produced.
Step (III): Emulsion polymerization or fine suspension polymerization of a vinyl chloride-based monomer in the presence of the vinyl chloride-based polymer obtained in Step (II) to obtain three maximum particles in a number-based particle size distribution. A vinyl chloride polymer having a specific value is produced.
工程(I′) 塩化ビニル系単量体を乳化重合又は微細懸濁重合させて、個数基準の粒径分布において1個の極大値を有する塩化ビニル系重合体ラテックスを製造する。 Step (I ') A vinyl chloride polymer latex having one maximum value in a number-based particle size distribution is produced by subjecting a vinyl chloride monomer to emulsion polymerization or fine suspension polymerization.
工程( Process ( IIII ′) 工程(I′)で得られた塩化ビニル系重合体ラテックスの存在下に塩化ビニル系単量体を乳化重合させて、個数基準の粒径分布において2個の極大値を有する塩化ビニル系重合体ラテックスを製造する。但し、この工程で用いる塩化ビニル系重合体ラテックス中の塩化ビニル系重合体と塩化ビニル系単量体の合計に占める塩化ビニル系重合体の量は3〜6重量%とする。') Emulsion polymerization of a vinyl chloride monomer in the presence of the vinyl chloride polymer latex obtained in step (I') to give a vinyl chloride polymer having two maximum values in the number-based particle size distribution Produce a polymer latex. However, the amount of the vinyl chloride polymer in the total of the vinyl chloride polymer and the vinyl chloride monomer in the vinyl chloride polymer latex used in this step is 3 to 6% by weight.
工程(Process ( IIIIII ′) 工程(′) Process ( IIII ′)で得られた塩化ビニル系重合体ラテックスの存在下に塩化ビニル系単量体を乳化重合させて、個数基準の粒径分布において3個の極大値を有する塩化ビニル系重合体ラテックスを製造する。但し、この工程で用いる塩化ビニル系重合体ラテックス中の塩化ビニル系重合体と塩化ビニル系単量体の合計に占める塩化ビニル系重合体の量は4〜12重量%とする。') Emulsion polymerization of a vinyl chloride monomer in the presence of the vinyl chloride polymer latex obtained in (1) to produce a vinyl chloride polymer latex having three maximum values in the number-based particle size distribution. I do. However, the amount of the vinyl chloride polymer in the total of the vinyl chloride polymer and the vinyl chloride monomer in the vinyl chloride polymer latex used in this step is 4 to 12% by weight.
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JP15832196A JP3552407B2 (en) | 1996-06-19 | 1996-06-19 | Method for producing vinyl chloride polymer |
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JP15832196A JP3552407B2 (en) | 1996-06-19 | 1996-06-19 | Method for producing vinyl chloride polymer |
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JPH101502A (en) | 1998-01-06 |
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