JP2004018728A

JP2004018728A - Method for producing graft copolymer

Info

Publication number: JP2004018728A
Application number: JP2002177275A
Authority: JP
Inventors: Tetsumi Ikeda; 池田　哲美; Katsuhiko Teramoto; 寺本　勝彦
Original assignee: Denki Kagaku Kogyo KK
Current assignee: Denka Co Ltd
Priority date: 2002-06-18
Filing date: 2002-06-18
Publication date: 2004-01-22

Abstract

<P>PROBLEM TO BE SOLVED: To stably obtain a graft copolymer containing a vinyl copolymer having a large average molecular weight and a vinyl copolymer having a small average molecular weight by a butch polymerization. <P>SOLUTION: When producing the graft copolymer by polymerizing 35-75 pts. wt. whole monomer mixture (Y) composed of an aromatic vinyl monomer, a vinyl cyanide monomer and as necessary a vinyl monomer copolymerizable with these monomers in the presence of 25-65 pts. wt. whole rubber-like polymer (X) (wherein X + Y is 100 pts. wt.), at first, 0-100 wt.% component X and 10.0-60.0 wt.% component Y are charged and these components are polymerized at 40-65°C for 0.5-3 hr and then, as necessary, a residual rubber-like polymer is charged and further, a residual 40.0-90.0 wt.% component Y is stepwisely or continuously charged and these components are polymerized at 40-90°C for 2-8 hr. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、ゴム状重合体存在下で、芳香族ビニル系単量体、シアン化ビニル系単量体、および必要に応じてこれら単量体と共重合可能なビニル系単量体から成る単量体混合物を重合するに際し、特定の条件下で少なくとも二段重合することによってグラフト共重合体を製造する製造方法、および特定の分子量分布を有するグラフト共重合体を同一バッチで製造する製造方法、並びにそれら製造方法によって得られるグラフト共重合体である。
【０００２】
【従来の技術】
芳香族ビニル系樹脂、特にポリスチレン樹脂、ＡＳ樹脂、ＡＢＳ樹脂は成形性、剛性に優れているため、これら熱可塑性樹脂は、射出成形、押出成形、真空成形などにより、目的の形状に付形され、家庭用品、電化製品などの部品として多量に使用されている。
【０００３】
これらの樹脂を種々の成形方法と組み合わせて用いる場合、樹脂の粘度をその成形法に応じた（溶融）粘度に調整することが必要である。例えば、ＡＢＳ樹脂を使用して真空成形加工をしようとする場合、成形加工時の延伸倍率が大きくなるに伴い、材料粘度を適当に高めることが必要である。この場合ＡＢＳ樹脂自体の平均分子量を大きくすること、ＡＢＳ樹脂に平均分子量の大きいＡＳ樹脂と平均分子量の小さいＡＳ樹脂との両成分を含有させること、あるいはＡＳ樹脂の分子量分布を調整して材料粘度高める方法が知られている。例えば、特開平７−３１６３９０号公報、特開平８−１２７０６１号公報、特開平１１−４９９２６号公報、特開平１１−２４１０９１号公報では、その成形方法に適した成形性を得るため、これまでのＡＢＳ樹脂に平均分子量の大きいＡＳ樹脂と平均分子量の小さいＡＳ樹脂を配合することで分子量の調整を行ってきた。
【０００４】
しかし、目的の粘度に調整するために用いられる平均分子量の小さい樹脂を得ることに関して製造上問題は無いが、一方の平均分子量の大きいビニル系共重合体は、例えば、特開昭６１−２５８８４０号公報に記載されているように、特別な重合方法で製造されており、この方法では現在、一般に普及されている重合設備では容易に、さらに、大量に製造することが難しい。というのも、重合時に発生する大量の反応熱を取り除くのが難しいからである。いわんや、別々に製造したものを混合するのではなく、同一の製造設備で重合の際に一括して平均分子量が大きいビニル系共重合体と平均分子量の小さいビニル系共重合体は、従来得られていないものであった。
また、目的の粘度を得るために大きな平均分子量を有する高分子量成分を配合する場合、造粒時の混錬不足により十分溶融しない状態で溶融混合され、分散性が不足し物性値がバラつくことで機械的強度の発現が生じ難く、また溶融混練するにあたっては十分な時間が要求されるので時間的立場から見ても生産性に劣るなどの欠点があった。
【０００５】
【発明が解決しようとする課題】
本発明は、上述の課題を解決することにある。
すなわち、別々に製造された平均分子量の大きいビニル系共重合体と平均分子量の小さいビニル系共重合体を配合して分子量の調整を行う方法ではなく、平均分子量の大きいビニル系共重合体と平均分子量の小さいビニル系共重合体を含有したグラフト共重合体を安定して同一の製造設備で一括重合して得ることにある。この一括重合方法を採用することによって、別々に得られた共重合体を混合配合するよりも生産コストを安価に得ることができる。また、これによって得られたグラフト共重合体を採用することによって、従来溶融混練時に生じていた分散不良、物性値のバラツキなどの欠点も改良することができることを見いだした。
【０００６】
【課題を解決するための手段】
すなわち、本発明は全ゴム状重合体（Ｘ）２５〜６５質量部存在下で、芳香族ビニル系単量体、シアン化ビニル系単量体、および必要に応じてこれら単量体と共重合可能なビニル系単量体から成る全単量体混合物（Ｙ）３５〜７５質量部を重合してグラフト共重合体を製造するに際し（但し、Ｘ＋Ｙ＝１００質量部とする）、
まず、最初に全ゴム状重合体（Ｘ）の０〜１００質量％および、全単量体混合物（Ｙ）の１０．０〜６０．０質量％を仕込み、重合温度４０〜６５℃で０．５〜３時間で重合し、
その後、必要に応じて残りのゴム状重合体（Ｘ）を投入し、さらに残りの全単量体混合物（Ｙ）の４０．０〜９０．０質量％を段階的または連続的に投入して、重合温度４０〜９０℃で２〜８時間重合することを特徴とするグラフト共重合体の製造方法である。
【０００７】
さらには、最初に全ゴム状重合体（Ｘ）の０〜１００質量％および、全単量体混合物（Ｙ）の１０．０〜６０．０質量％を仕込み、最初の仕込みの単量体混合物量に対して乳化剤を質量比で１００：５〜２０、連鎖移動剤を質量比で１００：０〜０．１、重合開始剤を質量比で１００：０〜０．１および、レドックスを質量比で１００：０〜０．３の割合で仕込み、重合温度４０〜６５℃で０．５〜３時間で重合した後、
必要に応じて残りの全ゴム状重合体（Ｘ）１００〜０質量％を仕込み、さらに残りの全単量体混合物（Ｙ）の９０．０〜４０．０質量％を段階的または連続的に投入し、同時に残りの単量体混合物量に対する乳化剤を質量比で１００：０〜５、連鎖移動剤を質量比で１００：０〜０．３、重合開始剤を質量比で１００：０．０１〜０．３および、レドックスを質量比で１００：０〜０．３の割合で段階的または連続的に投入して、重合温度４０〜９０℃で２〜８時間重合することを特徴とするグラフト共重合体の製造方法である。
【０００８】
より好ましくは、最初に全ゴム状重合体（Ｘ）の１００質量％および、全単量体混合物（Ｙ）中の芳香族ビニル系単量体８〜４８質量％、シアン化ビニル系単量体２〜２４質量％を仕込み（但し、１０．０質量％≦芳香族ビニル系単量体＋シアン化ビニル系単量体≦６０．０質量％）、さらに最初の仕込みの単量体混合物量に対して乳化剤を質量比で１００：５〜２０、連鎖移動剤を質量比で１００：０〜０．１、重合開始剤を質量比で１００：０〜０．１および、レドックスを質量比で１００：０〜０．３の割合で仕込み、重合温度４０〜６５℃で０．５〜３時間で重合した後、
終了と同時に残りの単量体混合物量に対する乳化剤を質量比で１００：０〜５、連鎖移動剤を質量比で１００：０〜０．３、重合開始剤を質量比で１００：０．０１〜０．３および、レドックスを質量比で１００：０〜０．３の割合で仕込み、続いて芳香族ビニル系単量体２４〜７２質量％、シアン化ビニル系単量体８〜３６質量％（但し、４０．０質量％≦芳香族ビニル系単量体＋シアン化ビニル系単量体≦９０．０質量％）を段階的または連続的に投入し、重合温度４０〜９０℃で２〜８時間重合することを特徴とするグラフト共重合体の製造方法である。また、これらの製造方法で得られたグラフト共重合体である。
【０００９】
以下、本発明を詳細に説明する。
本発明のグラフト共重合体の製造方法は、ゴム状重合体存在下に芳香族ビニル系単量体、シアン化ビニル系単量体、および必要に応じてこれらの単量体と共重合可能なビニル系単量体からなる単量体混合物を重合して得られるグラフト共重合体である。
【００１０】
本発明に係るグラフト共重合体の製造で用いられるゴム状重合体としては、特に制限は無いが、ポリブタジエン、ブタジエン−スチレン共重合体、ブタジエン−アクリロニトリル共重合体、ポリイソプレン、ポリクロロプレンなどのブタジエン系重合体、アクリル酸プロピル重合体、アクリル酸ブチル重合体などのアクリル酸エステル重合体、エチレン−プロピレン−共役ジエン系ゴムなどを挙げることができる。これらのゴム状重合体は単独でも２種以上を混合しても使用することもできる。特に、本発明は乳化重合法が用いられるのでゴム状重合体としてはラテックス状態での上記のゴム状重合体を用いることが好ましい。
なお、本発明の製造方法においては、ゴム状重合体の粒子径は特に限定されるものではないが、本発明で得られたグラフト共重合体およびその樹脂組成物を射出成形品、押出成形品などに用いる場合に、強度などを要求される成形品の場合にはゴム状重合体の粒子径は２００〜４２０ｎｍ、好ましくは２４０〜３９０ｎｍ、さらに好ましくは２８０〜３８０ｎｍの範囲にあるものを用いることが好ましい。
【００１１】
本発明に係るグラフト共重合体の製造に用いられる芳香族ビニル系単量体としては、特に制限は無いが、スチレン、α−メチルスチレン、ジメチルスチレン、ビニルトルエンなどが好ましい。これらのなかでもさらにスチレンが好ましい。シアン化ビニル系単量体としては、特に制限は無いが、アクリロニトリル、メタクリロニトリル、フマロニトリルなどが挙げられ、これらのなかでもさらにアクリロニトリルが好ましい。
【００１２】
必要に応じて用いられるこれら上記の単量体と共重合可能なビニル系単量体としては、特に制限は無いが、メタクリル酸メチル、メタクリル酸エチル、メタクリル酸プロピル、メタクリル酸ブチル、メタクリル酸−２−エチルヘキシル、メタクリル酸フェニル、メタクリル酸ベンジル、メタクリル酸イソボルニルなどのようなメタクリル酸エステル単量体、アクリル酸メチル、アクリル酸エチル、アクリル酸プロピル、アクリル酸ブチル、アクリル酸−２−エチルヘキシル、アクリル酸シクロヘキシルなどのアクリル酸エステル単量体、マレイン酸、イタコン酸、シトラコン酸などの不飽和ジカルボン酸単量体および、これらの無水物、マレイミド、Ｎ−メチルマレイミド、Ｎ−ブチルマレイミド、Ｎ−フェニルマレイミド、Ｎ−シクロヘキシルマレイミドなどの不飽和ジカルボン酸のイミド化合物単量体などが挙げられ、これらのビニル系単量体は、単独または２種以上を組み合わせても使用できる。
【００１３】
本発明の製造方法における全ゴム状重合体（Ｘ）と全単量体混合物（Ｙ）との全組成比は、ゴム状重合体２５〜６５質量部の存在下に、全単量体混合物（Ｙ）３５〜７５質量部の範囲で選ぶのが好ましい（ただし、全ゴム状重合体（Ｘ）＋全単量体混合物（Ｙ）＝１００質量部とする）。なお、ゴム状重合体ラテックスを用いた場合は、全ゴム状重合体（Ｘ）とは、ゴム状重合体ラテックスの固形分をいう。
【００１４】
また、ゴム状重合体は、全ゴム状重合体（Ｘ）の０〜１００質量％を最初に仕込んでもよい。その後残りを順次重合時に投下することであるが、好ましくは最初に全ゴム状重合体（Ｘ）の１００質量％を仕込んで製造することである。
【００１５】
また、本発明における全単量体混合物（Ｙ）中の各単量体の割合は、特に限定されるものではないが、最初に、全単量体混合物（Ｙ）の１０．０〜６０．０質量％を仕込み、残りを単量体混合物（Ｙ）の４０．０〜９０．０質量％を段階的または連続的に投入する。
【００１６】
また、本発明に係るグラフト共重合体の製造方法では、同一バッチで段階的に重合するが、段数は限定されるものではなく、許される限り何段階でも構わない。
【００１７】
本発明のグラフト共重合体の製造方法は、高分子量のビニル系共重合体を得るために２段階重合を行う方が好ましい。グラフト共重合体の製造方法としては、乳化重合法、懸濁重合法、塊状重合法、乳化−懸濁重合法などの公知の重合法を回分式および、または連続式と組み合わせて用いられる。これらのなかで、グラフト共重合体を製造する方法は乳化重合法によるのが好ましく、ラテックス状のゴム状重合体を用い、スチレン系単量体、シアン化ビニル系単量体、および必要に応じこれと共重合可能な単量体の単量体混合物を乳化重合法で重合するのが好ましい。
【００１８】
好ましい乳化重合法の例を示す。まず、最初に全ゴム状重合体（Ｘ）の１００質量％および、全単量体混合物（Ｙ）の芳香族ビニル系単量体８〜４８質量％、シアン化ビニル系単量体２〜２４質量％を仕込み（但し、１０．０質量％≦芳香族ビニル系単量体＋シアン化ビニル系単量体≦６０．０質量％）、
最初の仕込みの単量体混合物量に対して乳化剤を質量比で１００：５〜２０、連鎖移動剤を質量比で１００：０〜０．１、重合開始剤を質量比で１００：０〜０．１、レドックスを質量比で１００：０〜０．３の割合で仕込み、重合温度４０〜６５℃で０．５〜３時間で重合した後、終了と同時に残りの単量体混合物量に対する乳化剤を質量比で１００：０〜５、連鎖移動剤を質量比で１００：０〜０．３、重合開始剤を質量比で１００：０．０１〜０．３、レドックスを質量比で１００：０〜０．３の割合で仕込み、
続いて残り単量体混合物として芳香族ビニル系単量体２４〜７２質量％、シアン化ビニル系単量体８〜３６質量％（但し、４０．０質量％≦芳香族ビニル系単量体＋シアン化ビニル系単量体≦９０．０質量％）を段階的または連続的に投入し、重合温度４０〜９０℃で２〜８時間重合するグラフト共重合体の製造方法である。
【００１９】
使用する乳化剤は公知のものが使用でき、特に制限は無い。たとえば、高級脂肪酸塩（例えば、半硬化牛脂肪酸カリ石鹸等）、アルキル硫酸エステル塩、アルキルベンゼンスルホン酸塩、アルキル酸エステル塩、アルキルジフェニルエーテルスルホン酸塩などのアニオン性界面活性剤、また、ポリオキシエチレンアルキルエーテル、ポリオキシエチレン脂肪酸エステル、ソルビタン脂肪酸エステル、グリセリン脂肪酸エステルなどのノニオン性界面活性剤、さらにはアルキルアミン塩などのカチオン性界面活性剤を使用することができる。また、これらの乳化剤は単独でも、併用しても使用することができる。
【００２０】
また、重合開始剤としては、水溶性、油溶性の単独系、もしくはレドックス系のものでよく、例として、通常の過硫酸塩などの無機開始剤を単独で用いるか、あるいは亜硫酸塩、亜硫酸水素塩、チオ硫酸塩などと組み合わせてレドックス系開始剤として用いることもできる。さらに、ｔ−ブチルハイドロパーオキサイド、クメンハイドロパーオキサイド、ｔ−ブチルパーオキシアセテート、過酸化ベンゾイル、過酸化ラウロイルなどの有機過酸化物、アゾ化合物などを単独で用いるか、ホルムアルデヒドナトリウムスルホキシレートなどと組み合わせてレドックス系開始剤として用いることもできる。
【００２１】
レドックスとしては、特に制限は無いが、賦活剤、キレート剤、還元剤の少なくとも１種以上から構成されるのが好ましい。賦活剤はグルコース、デキストロース、ホルムアルデヒドナトリウムスルホキシレート、亜硫酸塩（例えば、亜硫酸ナトリウム）、亜硫酸水素塩（例えば、亜硫酸水素ナトリウム）、チオ硫酸塩（例えばチオ硫酸ナトリウム）などが使用できる。
キレート剤としては、ヘキサシアノ鉄（ＩＩＩ）カリウム、エチレンジアミン４酢酸塩などが使用できる。
還元剤としては硫酸第一鉄、ピロリン酸ナトリウム、リン酸ナトリウム、硫酸銅などが使用できる。
【００２２】
連鎖移動剤としては、特に制限は無いが、ｎ−オクチルメルカプタン、ｎ−ドデシルメルカプタン、ｔ−ドデシルメルカプタンなどのメルカプタン類、または、ターピノーレン、α−メチルスチレンダイマーなどが挙げられる。
【００２３】
これら、乳化剤、連鎖移動剤、重合開始剤、レドックスの割合は最初の仕込みの単量体混合物量１００に対しては質量比でそれぞれ乳化剤５〜２０、連鎖移動剤０〜０．１、重合開始剤０〜０．１および、レドックス０〜０．３の割合で仕込み、好ましくは乳化剤８〜１５、連鎖移動剤０〜０．０５、重合開始剤０〜０．０５および、レドックス０．１〜０．３である。
最初の重合終了と同時に残りの単量体混合物量１００に対してそれぞれ質量比で乳化剤０〜５、連鎖移動剤０〜０．３、重合開始剤０．０１〜０．３、レドックス０〜０．３の割合で仕込み、好ましくは乳化剤０〜３、連鎖移動剤０．０５〜０．３、重合開始剤０．０５〜０．３および、レドックスを０．０５〜０．３の割合で仕込むことである。
【００２４】
本発明の方法による高分子量含有重合体の回収方法は、例えば、得られた重合体ラテックスを常温まで冷却し、硫酸、塩酸、リン酸などの酸、または、塩化アルミニウム、塩化カルシウム、硫酸マグネシウム、硫酸アルミニウム、酢酸カルシウムなどの塩などの電解質により、酸凝固もしくは塩析させて重合体を沈殿せしめた後、さらに濾過、洗浄、乾燥して得ることができる。また、得られた重合体ラテックスを噴霧乾燥もしくは凍結乾燥などの手法で回収するなど、公知の回収方法を使用し得る。
【００２５】
本発明の製造方法で得られるグラフト共重合体をメチルエチルケトン（ＭＥＫ）に溶解させ、可溶分から回収される共重合体（ａ）の重量平均分子量は、１５万〜２５０万、好ましくは２０万〜２００万、さらに好ましくは２５万〜１５０万のものが得られる。また、重量平均分子量（Ｍｗ）と数平均分子量（Ｍｎ）の比Ｍｗ／ＭｎがＭｗ／Ｍｎ≧４．０、好ましくはＭｗ／Ｍｎ≧５．０、さらに好ましくはＭｗ／Ｍｎ≧６．０のものが得られる。
さらに、共重合体（ａ）は、後述する測定装置の計算機で波形解析し、主成分（ｂ），残りの成分（ｃ）の２成分に分けることが出来る。主成分（ｂ）の重量平均分子量は８万〜６０万、好ましくは１２万〜４０万、さらに好ましくは１５万〜３０万である。また、残りの成分（ｃ）の重量平均分子量は８０万以上、好ましくは１２０万以上、さらに好ましくは２００万以上であるものが好ましく製造することができる。
また、グラフト共重合体をＭＥＫに溶解する方法および各種平均分子量の値も、測定の方法も後述する方法で行ったものをいう。
【００２６】
本発明の製造方法で得られるグラフト共重合体のグラフト率は、３０〜１００％が好ましく、後記する通常のグラフト率の測定方法で得ることができる。
【００２７】
本発明のグラフト共重合体は、単独でも射出成形、押出成形用の樹脂として使用が可能である。さらに、その他の芳香族ビニル系共重合体、例えば芳香族ビニル系単量体、シアン化ビニル系単量体、および必要に応じてこれら単量体と共重合可能なビニル系単量体成分から得られた共重合体と混合させた樹脂組成物とすることも可能である。これらの単独樹脂および樹脂組成物は、真空成形、ブロー成形性に優れフィルム、シートにおいて偏肉防止などの優れた性質を示す。
【００２８】
【実施例】
下記の実施例および比較例で本発明を具体的に説明するが、本発明は以下の例に限定されるものではない。
【００２９】
実施例１
Ａ−１：グラフト共重合体の製造
（イ）ゴム状重合体の製造
攪拌機、加熱冷却装置、温度計、圧力計、原料・助剤添加装置を備えたステンレス製オートクレーブに、窒素置換後、ブタジエン１００質量部に対しロジン酸カリウム３．０質量部、ｔ−ドデシルメルカプタン０．３質量部、第二リン酸ナトリウム１．５質量部、脱イオン水７０質量部を仕込み、攪拌下、内温を５５℃に昇温した。内温が５５℃に達した時点で、過硫酸アンモニウム０．５質量部を添加した。数分後に発熱が起こり、重合の開始が確認された。内圧が０．１ＭＰａとなった時点で重合を終了し、冷却した。得られたゴム状重合体ラテックスの固形分濃度は５０％、ゴムの平均粒径３１０ｎｍであった。
【００３０】
（ロ）グラフト共重合体の製造
攪拌機、加熱冷却装置、温度計、原料・助剤添加装置を備えたステンレス製オートクレーブに、脱イオン水（ラテックス中の水分を含む）２７０質量部、半硬化牛脂肪酸カリ石鹸（花王社製ＫＳソープ）１．５質量部、スチレン１０．５質量部、アクリロニトリル４．５質量部を仕込み重合系内を窒素ガスで置換し、攪換下、上記実施例１の（イ）で得られたゴム状重合体ラテックス５０質量部（固形分として）を仕込み、内温を５０℃に昇温した。内温が途中の４８℃に達した時点で、脱イオン水１０質量部に硫酸第一鉄０．０００３質量部、エチレンジアミン四酢酸０．０００７５質量部、ホルムアルデヒドナトリウムスルホキシレート０．０２２５質量部の割合からなる溶液を添加し、内温５０℃で１時間重合した。
続けて脱イオン水１０質量部に硫酸第一鉄０．００１４質量部、エチレンジアミン四酢酸０．００２４５質量部、ホルムアルデヒドナトリウムスルホキシレート０．０７３５質量部を溶解した溶液を添加した。添加後、スチレン２４．５質量部、アクリロニトリル１０．５質量部からなる単量体混合物と脱イオン水２７質量部、高級脂肪酸石鹸０．５２５質量部、ｔ−ブチルパーオキシアセテート０．０３５質量部、α−メチルスチレンダイマー０．０３５質量部の割合よりなる溶液を連続添加し、温度６０℃で５時間重合した。
重合終了後内温を冷却し、得られたラテックスに老化防止剤（チバスペシャリティケミカルズ社製イルガノックス１０７６）１．５質量部を添加し、続いてラテックスを温度９５℃加熱した硫酸マグネシウム水溶液に加えて凝固し、濾過、洗浄、乾燥して、白色粉末状の樹脂組成物を得た。
このグラフト共重合体をＡ−１とする。後記した各測定方法に従って測定した結果を表１に示す。
【００３１】
実施例２
Ａ−２：グラフト共重合体の製造
攪拌機、加熱冷却装置、温度計、原料・助剤添加装置を備えたステンレス製オートクレーブに、脱イオン水（ラテックス中の水分を含む）２７０質量部、半硬化牛脂肪酸カリ石鹸（花王社製ＫＳソープ）２．４質量部、スチレン１６．８質量部、アクリロニトリル７．２質量部を仕込み重合系内を窒素ガスで置換し、攪換下、上記実施例１の（イ）で得られたゴム状重合体ラテックス４０質量部（固形分として）を仕込み、内温を５０℃に昇温した。内温が途中の４８℃に達した時点で、脱イオン水１０質量部に硫酸第一鉄０．０００４８質量部、エチレンジアミン四酢酸０．００１２質量部、ホルムアルデヒドナトリウムスルホキシレート０．０３６質量部の割合からなる溶液を添加し、内温５０℃で１時間重合した。
続けて脱イオン水１０質量部に硫酸第一鉄０．００１４４質量部、エチレンジアミン四酢酸０．００２５２質量部、ホルムアルデヒドナトリウムスルホキシレート０．０７５６質量部を溶解した溶液を添加した。添加後、スチレン２５．２質量部、アクリロニトリル１０．８質量部からなる単量体混合物と脱イオン水２７質量部、半硬化牛脂肪酸カリ石鹸０．５４質量部、ｔ−ブチルパーオキシアセテート０．０３６質量部、ターピノーレン０．０３６質量部の割合よりなる溶液を連続添加し、温度６０℃で５時間重合した。
重合終了後内温を冷却し、得られたラテックスに老化防止剤（チバスペシャリティケミカルズ社製イルガノックス１０７６）１．５質量部を添加し、続いてラテックスを温度９５℃加熱した硫酸マグネシウム水溶液に加えて凝固し、濾過、洗浄、乾燥して、白色粉末状の樹脂組成物を得た。
このグラフト重合体をＡ−２とする。前記した各測定方法に従って測定した結果を表１に示す。
【００３２】
実施例３
Ａ−３：グラフト共重合体の製造
攪拌機、加熱冷却装置、温度計、原料・助剤添加装置を備えたステンレス製オートクレーブに、脱イオン水（ラテックス中の水分を含む）２７０質量部、半硬化牛脂肪酸カリ石鹸（花王社製ＫＳソープ）１．５質量部、スチレン１１．２５質量部、アクリロニトリル３．７５質量部を仕込み重合系内を窒素ガスで置換し、攪換下、上記実施例１の（イ）で得られたゴム状重合体ラテックス５０質量部（固形分として）を仕込み、内温を５０℃に昇温した。内温が途中の４８℃に達した時点で、脱イオン水１０質量部に硫酸第一鉄０．０００３質量部、エチレンジアミン四酢酸０．０００７５質量部、ホルムアルデヒドナトリウムスルホキシレート０．０２２５質量部の割合からなる溶液を添加し、内温５０℃で１時間重合した。
続けて脱イオン水１０質量部に硫酸第一鉄０．００１４質量部、エチレンジアミン四酢酸０．００２４５質量部、ホルムアルデヒドナトリウムスルホキシレート０．０７３５質量部を溶解した溶液を添加した。添加後、スチレン２６．２５質量部、アクリロニトリル８．７５質量部からなる単量体混合物と脱イオン水２７質量部、高級脂肪酸石鹸０．５２５質量部、過硫酸カリウム０．０３５質量部、α−メチルスチレンダイマー０．０３５質量部の割合よりなる溶液を連続添加し、温度６０℃で５時間重合した。
重合終了後内温を冷却し、得られたラテックスに老化防止剤（チバスペシャリティケミカルズ社製イルガノックス１０７６）１．５質量部を添加し、続いてラテックスを温度９５℃加熱した硫酸マグネシウム水溶液に加えて凝固し、濾過、洗浄、乾燥して、白色粉末状の樹脂組成物を得た。
このグラフト重合体をＡ−３とする。前記した各測定方法に従って測定した結果を表１に示す
【００３３】
実施例４
Ａ−４：グラフト共重合体の製造
攪拌機、加熱冷却装置、温度計、原料・助剤添加装置を備えたステンレス製オートクレーブに、脱イオン水（ラテックス中の水分を含む）２７０質量部、半硬化牛脂肪酸カリ石鹸（花王社製ＫＳソープ）１．５質量部、ｔ−ブチルパーオキシアセテート０．００１５質量部、スチレン１１．２５質量部、アクリロニトリル３．７５質量部を仕込み重合系内を窒素ガスで置換し、攪換下、上記実施例１の（イ）で得られたゴム状重合体ラテックス５０質量部（固形分として）を仕込み、内温を５０℃に昇温した。内温が途中の４８℃に達した時点で、脱イオン水１０質量部に硫酸第一鉄０．０００３質量部、エチレンジアミン四酢酸０．０００７５質量部、ホルムアルデヒドナトリウムスルホキシレート０．０２２５質量部を溶解した溶液を添加し、内温５０℃で１時間重合した。
続けて脱イオン水１０質量部に硫酸第一鉄０．００１４質量部、エチレンジアミン四酢酸０．００２４５質量部、ホルムアルデヒドナトリウムスルホキシレート０．０７３５質量部を溶解した溶液を添加した。添加後、スチレン２６．２５質量部、アクリロニトリル８．７５質量部からなる単量体混合物と脱イオン水２７質量部、高級脂肪酸石鹸０．５２５質量部、ｔ−ブチルパーオキシアセテート０．０３５質量部、ｎ−ドデシルメルカプタン０．０３５質量部の割合よりなる溶液を連続添加し、温度６０℃で５時間重合した。
重合終了後内温を冷却し、得られたラテックスに老化防止剤（チバスペシャリティケミカルズ社製イルガノックス１０７６）１．５質量部を添加し、続いてラテックスを温度９５℃加熱した硫酸マグネシウム水溶液に加えて凝固し、濾過、洗浄、乾燥して、白色粉末状の樹脂組成物を得た。
このグラフト重合体をＡ−４とする。前記した各測定方法に従って測定した結果を表１に示す
【００３４】
実施例５
Ａ−５：グラフト共重合体の製造
攪拌機、加熱冷却装置、温度計、原料・助剤添加装置を備えたステンレス製オートクレーブに、脱イオン水（ラテックス中の水分を含む）２７０質量部、半硬化牛脂肪酸カリ石鹸（花王社製ＫＳソープ）１．５質量部、ｔ−ブチルパーオキシアセテート０．００７５質量部、α−メチルスチレンダイマー０．００７５質量部、スチレン１１．２５質量部，アクリロニトリル３．７５質量部を仕込み重合系内を窒素ガスで置換し、攪換下、上記実施例１の（イ）で得られたゴム状重合体ラテックス５０質量部（固形分として）を仕込み、内温を５０℃に昇温した。内温が途中の４８℃に達した時点で、脱イオン水１０質量部に硫酸第一鉄０．０００３質量部、エチレンジアミン四酢酸０．０００７５質量部、ホルムアルデヒドナトリウムスルホキシレート０．０２２５質量部を溶解した溶液を添加し、内温５０℃で１時間重合した。
続けて脱イオン水１０質量部に硫酸第一鉄０．００１４質量部、エチレンジアミン四酢酸０．００２４５質量部、ホルムアルデヒドナトリウムスルホキシレート０．０７５５質量部を溶解した溶液を添加した。添加後、スチレン２６．２５質量部、アクリロニトリル８．７５質量部からなる単量体混合物と脱イオン水２７質量部、高級脂肪酸石鹸０．５２５質量部、ｔ−ブチルパーオキシアセテート０．０３５質量部、ｔ−ドデシルメルカプタン０．０３５質量部の割合よりなる溶液を連続添加し、温度６０℃で５時間重合した。
重合終了後内温を冷却し、得られたラテックスに老化防止剤（チバガイギー社製イルガノックス１０７６）１．５質量部を添加し、続いてラテックスを温度９５℃加熱した硫酸マグネシウム水溶液に加えて凝固し、濾過、洗浄、乾燥して、白色粉末状の樹脂組成物を得た。
このグラフト重合体をＡ−５とする。前記した各測定方法に従って測定した結果を表１に示す
【００３５】
参考比較例１
Ｂ−１：グラフト共重合体の製造
攪拌機、加熱冷却装置、温度計、原料・助剤添加装置を備えたステンレス製オートクレーブに、上記実施例１の（イ）で得られたゴム状重合体ラテックス５０質量部（固形分として）、脱イオン水（ラテックス中の水分を含む）２７０質量部を仕込み、重合系内を窒素ガスで置換し、攪拌下、内温５０℃に昇温した。内温が途中の４８℃に達した時点で、脱イオン水１３質量部に、硫酸第一鉄７水塩０．００２５質量部、エチレンジアミン４酢酸４ナトリウム２水塩０．００５質量部、ホルムアルデヒドナトリウムスルホキシレート０．３質量部を溶解した溶液を添加した。スチレン３５質量部、アクリロニトリル１５質量部と脱イオン水２７質量部に、半硬化牛脂肪酸カリ石鹸１．５質量部、ジイソプロピルベンゼンハイドロパーオキサイド０．２質量部、α−メチルスチレンダイマー０．２５質量部よりなる溶液を連続添加開始し、６０℃の温度で５時間重合した。その後、７０℃の温度で２時間反応を継続した後、内温を冷却した。得られた混合ラテックスに老化防止剤（イルガノックス１０７６）１．５部を添加し、次いでラテックスを温度９５℃に加熱した硫酸マグネシウム水溶液に加えて凝固し、濾過、洗浄、乾燥して、白色粉末状の樹脂組成物を得た。このグラフト重合体をＢ−１とする。結果を表１に示す。
【００３６】
参考比較例２
Ｂ−２：グラフト共重合体の製造
攪拌機、加熱冷却装置、温度計、原料・助剤添加装置を備えたステンレス製オートクレーブに、上記実施例１の（イ）で得られたゴム状重合体ラテックス５０質量部（固形分として）、脱イオン水（ラテックス中の水分を含む）２７０質量部を仕込み、重合系内を窒素ガスで置換し、攪拌下、内温５０℃に昇温した。内温が途中の４８℃に達した時点で、脱イオン水１３質量部に、硫酸第一鉄７水塩０．００２５質量部、エチレンジアミン４酢酸４ナトリウム２水塩０．００５質量部、ホルムアルデヒドナトリウムスルホキシレート０．３質量部よりなる溶液を添加した。スチレン３５質量部、アクリロニトリル１５質量部と脱イオン水２７質量部に、半硬化牛脂肪酸カリ石鹸１．５質量部、ジイソプロピルベンゼンハイドロパーオキサイド０．１質量部、α−メチルスチレンダイマー０．１質量部よりなる溶液を連続添加開始し、６０℃の温度で５時間重合した。その後、７０℃の温度で２時間反応を継続した後、内温を冷却した。得られた混合ラテックスに老化防止剤（イルガノックス１０７６）１．５部を添加し、次いでラテックスを温度９５℃に加熱した硫酸マグネシウム水溶液に加えて凝固し、濾過、洗浄、乾燥して、白色粉末状の樹脂組成物を得た。このグラフト重合体をＢ−２とする。結果を表１に示す。
【００３７】
なお、いずれの実施例、比較例の製造では、異常発熱なども生じることもなく、実施することができた。
【００３８】
【表１】

【００３９】
各実施例および比較例中の各物性は、下記のようにして測定した。
（１）重量平均分子量およびＭｗ／Ｍｎ
グラフト共重合体のメチルエチルケトン（ＭＥＫ）可溶分の共重合体（ａ）の重量平均分子量は、ゲル・パーミエーション・クロマトグラフィー（ＧＰＣ）装置を用い、次の条件で測定したもので、分子量はポリスチレン換算値である。
装　置；Ｓｈｏｄｅｘ製、「ＳＹＳＴＥＭ−２１」
カラム；ＰＬｇｅｌ　ＭＩＸＥＤ−Ｂ
温　度；４０℃
溶　媒；テトラヒドロフラン
検　出；ＲＩ
濃　度；０．２％
注入量；１００μｌ
検量線；標準ポリスチレン（Ｐｏｌｙｍｅｒ　Ｌａｂｏｒａｔｏｒｉｅｓ製）を用い、溶離時間と溶出量との関係を分子量と変換して各種平均分子量を求めた。
【００４０】
（イ）なお、グラフト共重合体からメチルエチルケトン（ＭＥＫ）可溶分を抽出する条件は下記の条件で行った。
グラフト共重合体ラテックス約２０ｇをメタノール１００ｍｌで析出、凝固させ、凝固物は濾紙を用いて吸引濾過する。濾過物は室温で２４時間、真空乾燥機で約４時間乾燥させる。得られた試料の約１．２ｇを１００ｍｌ三角フラスコに取り、メチルエチルケトン（ＭＥＫ）３０ｇを加えた後、温度２３℃で２４時間攪拌し、その後、遠心分離器機（日立製作所製ＣＲ２６Ｈ）でメチルエチルケトン（ＭＥＫ）に対する不溶分の分離を実施し、遠心分離操作後３０分静置した。この遠心分離器の操作条件を次の通り設定した。
温度　：−９℃
回転数：２３，０００ｒｐｍ
時間　：５０分
遠心分離させた溶液の上澄み液と沈殿物とを分離し、上澄み液をメタノール１５０ｍｌが入れてある３００ｍｌビーカーに注ぎ入れて、析出させ、析出物を濾紙を用いて吸引濾過する。濾過物は室温で２４時間乾燥させ、次に真空乾燥機で４時間残溶剤を飛ばして試料を得た。
【００４１】
（ロ）主成分の低分子側と従成分の高分子量側との解析
なお、グラフト共重合体のメチルエチルケトン（ＭＥＫ）可溶分の重量平均分子量は、ＧＰＣ溶離曲線において低分子量側の主ピークと高分子量側の従ピークとが明確に区別できる場合、主ピークと従ピークに対応する位置の対照ガウス分布を想定して重量平均分子量および数平均分子量を求める方法でおこなった。
また、残り高分子側における従ピークが目立たずあるは判別が難しい場合は、主ピークで想定したガウス分布から外れた高分子量側の裾部についてトライアンドエラーで最適なガウス分布を想定しながら、重量平均分子量および数平均分子量を求める方法で求めた。
なお、ＧＰＣ溶離曲線を溶出量ｍｌ（ｍｖ）と溶出時間を０．５ｍｌ／ｓｅｃごとに分割して計算した。詳細な計算はＧＰＣ装置に付設されているデーター処理機東洋曹達ＳＣ−８０２０を用いて分子量分布曲線および各種平均分量値を求めた。
【００４２】
（２）ゴム状重合体ラテックス中のゴムの体積平均粒子径の測定方法
本発明のゴム状重合体の体積平均粒子径は、レーザー回折散乱法で求めた。その測定条件は以下の通りである。
装置：ＣＯＵＬＴＥＲ　ＬＳ　２３０（ＣＯＵＬＴＥＲ社製）
濃度：２．０％
希釈溶媒：蒸留水
解析ソフトウエアー：Ｖｅｒｓｉｏｎ２．０５
【００４３】
（３）グラフト率の測定方法
本発明のグラフト共重合体のグラフト率は、次の方法で求めた。
グラフト共重合体ラテックス約２０ｇをメタノール１００ｍｌで析出、凝固させ、凝固物を濾紙を用いて吸引濾過する。濾過物は真空乾燥機で２４時間、室温で乾燥させる。得られた試料の約１．２ｇを１００ｍｌ三角フラスコに取り、メチルエチルケトン（ＭＥＫ）３０ｇを加えた後、温度２３℃で２４時間攪拌し、その後遠心分離器機でメチルエチルケトン（ＭＥＫ）に対する不溶分の分離を実施し、遠心分離操作後３０分静置した。この遠心分離器の操作条件を次の通り設定した。
温度：−９℃
回転数：２０，０００ｒｐｍ
時間：６０分
遠心分離させた溶液の上澄液と沈殿物とを分離し、沈殿物は真空乾燥機で乾燥し、不溶分ｘとした。さらに、この不溶分の試料を用いてケルダール窒素法によって定量したアクリロニトリル単量体の質量ｙと熱分解ガスクロマトグラフィーにより定量したスチレン単量体の質量ｚを求め、グラフト率（％）＝１００×（ｙ＋ｚ）／｛ｘ−（ｙ＋ｚ）｝の式から計算した。
【００４４】
図１に、実施例１のＧＰＣによる分子量分布曲線を示す。また、図２に一般的なグラフト共重合体の製造方法である参考比較例１のＧＰＣによる分子量分布曲線を示す。この図で明らかなとおり、本発明の製造方法によるとＧＰＣ分子量分布曲線は主成分の低分子両側のピークと高分子量側とピークないしはショルダーを有するビニル系共重合体が得られ、高分子量を含有したグラフト共重合体の一括製造することができた。
【００４５】
【発明の効果】
本発明の製造方法に従い多段重合を行うと、製造時の異常発熱反応もなく定法の温度制御でビニル系共重合体の高分子量を含有したグラフト共重合体の製造を行うことができた。さらには、さまざまな分子量および分子量分布を有すグラフト共重合体を得ることができるので、他樹脂と混合した場合に高分子量側の分散性にも優れたものが得られ、押出成形法で製造されたシートの熱加工性、とりわけ真空成形性、圧空成形性に好適である。
【図面の簡単な説明】
【図１】実施例１（Ａ−１）のＧＰＣによる分子量分布曲線である。
【図２】参考比較例１（Ｂ−１）のＧＰＣによる分子量分布曲線である。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a single monomer comprising an aromatic vinyl monomer, a vinyl cyanide monomer, and a vinyl monomer copolymerizable with these monomers, if necessary, in the presence of a rubbery polymer. When polymerizing the monomer mixture, a production method for producing a graft copolymer by performing at least two-stage polymerization under specific conditions, and a production method for producing a graft copolymer having a specific molecular weight distribution in the same batch, And a graft copolymer obtained by these production methods.
[0002]
[Prior art]
Aromatic vinyl resins, especially polystyrene resins, AS resins, and ABS resins are excellent in moldability and rigidity. Therefore, these thermoplastic resins are formed into a desired shape by injection molding, extrusion molding, vacuum molding, or the like. It is used in large quantities as parts for household goods, electrical appliances and the like.
[0003]
When these resins are used in combination with various molding methods, it is necessary to adjust the viscosity of the resin to a (melt) viscosity according to the molding method. For example, when vacuum forming is to be performed using an ABS resin, it is necessary to appropriately increase the material viscosity as the draw ratio at the time of forming increases. In this case, increasing the average molecular weight of the ABS resin itself, making the ABS resin contain both an AS resin having a large average molecular weight and an AS resin having a small average molecular weight, or adjusting the molecular weight distribution of the AS resin to adjust the material viscosity Methods of enhancing are known. For example, in JP-A-7-316390, JP-A-8-127061, JP-A-11-49926, and JP-A-11-241091, in order to obtain moldability suitable for the molding method, The molecular weight has been adjusted by blending an AS resin having a large average molecular weight and an AS resin having a small average molecular weight into the ABS resin.
[0004]
However, although there is no problem in production with respect to obtaining a resin having a small average molecular weight used for adjusting the viscosity to a desired value, a vinyl copolymer having a large average molecular weight is, for example, disclosed in JP-A-61-258840. As described in the gazette, it is produced by a special polymerization method, and it is difficult to produce easily and in large quantities by a polymerization equipment which is currently widely used. This is because it is difficult to remove a large amount of reaction heat generated during polymerization. In other words, instead of mixing separately manufactured products, vinyl copolymers with a high average molecular weight and vinyl copolymers with a low average molecular weight can be obtained at the same time during polymerization in the same manufacturing equipment. Was not.
Also, when compounding a high molecular weight component having a large average molecular weight in order to obtain the desired viscosity, it is melted and mixed in a state where it is not sufficiently melted due to insufficient kneading during granulation, resulting in insufficient dispersibility and uneven physical property values. However, there is a drawback that the mechanical strength is hardly developed, and sufficient time is required for melt-kneading, so that the productivity is inferior even from the viewpoint of time.
[0005]
[Problems to be solved by the invention]
The present invention is to solve the above-mentioned problem.
That is, rather than a method of adjusting the molecular weight by blending separately produced vinyl copolymer having a large average molecular weight and a vinyl copolymer having a small average molecular weight, a vinyl copolymer having a large average molecular weight and a An object of the present invention is to obtain a graft copolymer containing a vinyl copolymer having a small molecular weight stably and collectively with the same production equipment. By employing this batch polymerization method, it is possible to obtain a lower production cost than by mixing and blending separately obtained copolymers. It has also been found that by employing the graft copolymer thus obtained, defects such as poor dispersion and variations in physical properties which have conventionally occurred during melt kneading can be improved.
[0006]
[Means for Solving the Problems]
That is, in the present invention, an aromatic vinyl monomer, a vinyl cyanide monomer, and, if necessary, a copolymer with these monomers in the presence of 25 to 65 parts by mass of the whole rubbery polymer (X). In producing a graft copolymer by polymerizing 35 to 75 parts by mass of a total monomer mixture (Y) composed of possible vinyl monomers (provided that X + Y = 100 parts by mass),
First, 0 to 100% by mass of the total rubbery polymer (X) and 10.0 to 60.0% by mass of the total monomer mixture (Y) are charged. Polymerized in 5 to 3 hours,
Thereafter, if necessary, the remaining rubbery polymer (X) is charged, and 40.0 to 90.0% by mass of the remaining monomer mixture (Y) is further charged stepwise or continuously. And a polymerization temperature of 40 to 90 ° C. for 2 to 8 hours.
[0007]
Further, first, 0 to 100% by mass of the total rubbery polymer (X) and 10.0 to 60.0% by mass of the total monomer mixture (Y) are charged, and the monomer mixture of the first charging is added. The emulsifier is 100: 5 to 20 by mass, the chain transfer agent is 100: 0 to 0.1 by mass, the polymerization initiator is 100: 0 to 0.1 by mass, and the redox is mass by mass. At a ratio of 100: 0 to 0.3 and polymerization at a polymerization temperature of 40 to 65 ° C. for 0.5 to 3 hours,
If necessary, 100 to 0% by mass of the remaining rubber-like polymer (X) is charged, and 90.0 to 40.0% by mass of the remaining monomer mixture (Y) is gradually or continuously added. At the same time, the emulsifier and the chain transfer agent with respect to the amount of the remaining monomer mixture are 100: 0 to 5 by mass, the chain transfer agent is 100: 0 to 0.3 by mass, and the polymerization initiator is 100: 0.01 by mass. Grafting characterized in that redox is added stepwise or continuously at a weight ratio of 100: 0 to 0.3 and redox is polymerized at a polymerization temperature of 40 to 90 ° C for 2 to 8 hours. This is a method for producing a copolymer.
[0008]
More preferably, first, 100% by mass of the total rubbery polymer (X) and 8 to 48% by mass of the aromatic vinyl monomer in the total monomer mixture (Y), and the vinyl cyanide monomer 2 to 24% by mass (however, 10.0% by mass ≦ aromatic vinyl monomer + vinyl cyanide monomer ≦ 60.0% by mass), and further to the monomer mixture amount of the first charge On the other hand, the emulsifier is 100: 5 to 20 by mass, the chain transfer agent is 100: 0 to 0.1 by mass, the polymerization initiator is 100: 0 to 0.1 by mass, and the redox is 100 by mass. : After charging at a ratio of 0 to 0.3 and polymerizing at a polymerization temperature of 40 to 65 ° C for 0.5 to 3 hours,
At the same time as the completion, the emulsifier to the remaining monomer mixture amount is 100: 0 to 5 in mass ratio, the chain transfer agent is 100: 0 to 0.3 in mass ratio, and the polymerization initiator is 100: 0.01 to 100 in mass ratio. 0.3 and redox at a mass ratio of 100: 0 to 0.3, followed by 24-72% by mass of an aromatic vinyl monomer and 8-36% by mass of a vinyl cyanide monomer ( However, 40.0% by mass ≦ aromatic vinyl monomer + vinyl cyanide monomer ≦ 90.0% by mass) is added stepwise or continuously, and the polymerization temperature is 40 to 90 ° C. and 2 to 8%. This is a method for producing a graft copolymer, which is characterized by polymerizing for a time. Further, it is a graft copolymer obtained by these production methods.
[0009]
Hereinafter, the present invention will be described in detail.
The method for producing a graft copolymer of the present invention can be copolymerized with an aromatic vinyl monomer, a vinyl cyanide monomer, and, if necessary, these monomers in the presence of a rubbery polymer. It is a graft copolymer obtained by polymerizing a monomer mixture composed of vinyl monomers.
[0010]
The rubbery polymer used in the production of the graft copolymer according to the present invention is not particularly limited, but includes butadiene such as polybutadiene, butadiene-styrene copolymer, butadiene-acrylonitrile copolymer, polyisoprene, and polychloroprene. Acrylate polymers such as propylene acrylate polymer and butyl acrylate polymer; and ethylene-propylene-conjugated diene rubber. These rubbery polymers can be used alone or in combination of two or more. In particular, since the present invention employs an emulsion polymerization method, it is preferable to use the above-mentioned rubbery polymer in a latex state as the rubbery polymer.
In the production method of the present invention, the particle size of the rubbery polymer is not particularly limited, but the graft copolymer obtained by the present invention and the resin composition thereof are injection-molded, extruded. In the case of a molded article requiring strength or the like, a rubber-like polymer having a particle size of 200 to 420 nm, preferably 240 to 390 nm, more preferably 280 to 380 nm is used. Is preferred.
[0011]
The aromatic vinyl monomer used for the production of the graft copolymer according to the present invention is not particularly limited, but styrene, α-methylstyrene, dimethylstyrene, vinyltoluene and the like are preferable. Of these, styrene is more preferred. The vinyl cyanide-based monomer is not particularly limited, but includes acrylonitrile, methacrylonitrile, fumaronitrile, and the like. Of these, acrylonitrile is more preferable.
[0012]
The vinyl monomer copolymerizable with the above monomers used as necessary is not particularly limited, but methyl methacrylate, ethyl methacrylate, propyl methacrylate, propyl methacrylate, methacrylic acid- Methacrylate monomers such as 2-ethylhexyl, phenyl methacrylate, benzyl methacrylate, isobornyl methacrylate, etc., methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, acrylic Acrylic acid ester monomers such as cyclohexyl acid, unsaturated dicarboxylic acid monomers such as maleic acid, itaconic acid and citraconic acid, and their anhydrides, maleimide, N-methylmaleimide, N-butylmaleimide, N-phenyl Maleimide, N-cyclohex Imide compound monomer of unsaturated dicarboxylic acids and the like, such as Rumareimido, these vinyl monomers may be used alone or in combination of two or more.
[0013]
In the production method of the present invention, the total composition ratio of the entire rubber-like polymer (X) and the total monomer mixture (Y) is determined in the presence of the rubber-like polymer in an amount of 25 to 65 parts by mass. Y) It is preferable to select from 35 to 75 parts by mass (provided that the total rubbery polymer (X) + the total monomer mixture (Y) = 100 parts by mass). When a rubber-like polymer latex is used, the total rubber-like polymer (X) refers to the solid content of the rubber-like polymer latex.
[0014]
Further, the rubbery polymer may be initially charged with 0 to 100% by mass of the total rubbery polymer (X). Thereafter, the remainder is sequentially dropped at the time of polymerization. Preferably, the production is performed by initially charging 100% by mass of the entire rubbery polymer (X).
[0015]
In addition, the proportion of each monomer in the total monomer mixture (Y) in the present invention is not particularly limited, but first, 10.0 to 60.% of the total monomer mixture (Y). 0% by mass is charged, and the remaining 40.0 to 90.0% by mass of the monomer mixture (Y) is charged stepwise or continuously.
[0016]
In the method for producing a graft copolymer according to the present invention, polymerization is performed stepwise in the same batch. However, the number of stages is not limited, and any number of stages may be used as long as it is allowed.
[0017]
In the method for producing a graft copolymer of the present invention, two-stage polymerization is preferably performed in order to obtain a high-molecular-weight vinyl copolymer. As a method for producing the graft copolymer, a known polymerization method such as an emulsion polymerization method, a suspension polymerization method, a bulk polymerization method, or an emulsion-suspension polymerization method is used in combination with a batch system or a continuous system. Among these, the method for producing the graft copolymer is preferably an emulsion polymerization method, using a latex-like rubbery polymer, and using a styrene monomer, a vinyl cyanide monomer, and if necessary. It is preferable to polymerize a monomer mixture of a monomer copolymerizable therewith with an emulsion polymerization method.
[0018]
The example of a preferable emulsion polymerization method is shown. First, 100% by mass of the entire rubbery polymer (X), 8 to 48% by mass of the aromatic vinyl monomer of the total monomer mixture (Y), and 2 to 24% of the vinyl cyanide monomer Mass% (however, 10.0 mass% ≦ aromatic vinyl monomer + vinyl cyanide monomer ≦ 60.0 mass%),
The emulsifier is 100: 5 to 20 in mass ratio, the chain transfer agent is 100: 0 to 0.1 in mass ratio, and the polymerization initiator is 100: 0 to 0 in mass ratio to the monomer mixture amount of the first charge. 1. Redox is charged at a mass ratio of 100: 0 to 0.3, polymerized at a polymerization temperature of 40 to 65 ° C for 0.5 to 3 hours, and at the same time as the termination, the emulsifier to the remaining monomer mixture amount In a mass ratio of 100: 0 to 5, a chain transfer agent in a mass ratio of 100: 0 to 0.3, a polymerization initiator in a mass ratio of 100: 0.01 to 0.3, and a redox in a mass ratio of 100: 0. Charge at a rate of ~ 0.3,
Subsequently, as the remaining monomer mixture, an aromatic vinyl monomer is 24 to 72% by mass, and a vinyl cyanide monomer is 8 to 36% by mass (provided that 40.0% by mass ≦ aromatic vinyl monomer + This is a method for producing a graft copolymer in which a vinyl cyanide-based monomer ≤ 90.0% by mass) is added stepwise or continuously and polymerized at a polymerization temperature of 40 to 90 ° C for 2 to 8 hours.
[0019]
A known emulsifier can be used, and there is no particular limitation. For example, anionic surfactants such as higher fatty acid salts (for example, semi-hardened cattle fatty acid potash soap), alkyl sulfate salts, alkyl benzene sulfonate salts, alkyl acid ester salts, alkyl diphenyl ether sulfonate salts, and polyoxyethylene Nonionic surfactants such as alkyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters and glycerin fatty acid esters, and cationic surfactants such as alkylamine salts can be used. These emulsifiers can be used alone or in combination.
[0020]
Further, the polymerization initiator may be a water-soluble, oil-soluble single system, or a redox system, for example, a single inorganic initiator such as a normal persulfate, or a sulfite, hydrogen sulfite It can also be used as a redox initiator in combination with salts, thiosulfates, and the like. Furthermore, t-butyl hydroperoxide, cumene hydroperoxide, t-butyl peroxyacetate, organic peroxides such as benzoyl peroxide, lauroyl peroxide, azo compounds, etc. may be used alone or formaldehyde sodium sulfoxylate. Can be used as a redox initiator.
[0021]
The redox is not particularly limited, but is preferably composed of at least one of an activator, a chelating agent, and a reducing agent. As the activator, glucose, dextrose, formaldehyde sodium sulfoxylate, sulfite (eg, sodium sulfite), bisulfite (eg, sodium bisulfite), thiosulfate (eg, sodium thiosulfate) and the like can be used.
As the chelating agent, potassium hexacyanoiron (III), ethylenediaminetetraacetate and the like can be used.
As the reducing agent, ferrous sulfate, sodium pyrophosphate, sodium phosphate, copper sulfate and the like can be used.
[0022]
The chain transfer agent is not particularly limited, and includes mercaptans such as n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, terpinolene, α-methylstyrene dimer, and the like.
[0023]
These emulsifiers, chain transfer agents, polymerization initiators, and redox ratios are as follows: mass ratio of emulsifiers 5 to 20, chain transfer agent 0 to 0.1, Agents 0 to 0.1 and redox 0 to 0.3, preferably emulsifiers 8 to 15, chain transfer agent 0 to 0.05, polymerization initiator 0 to 0.05, and redox 0.1 to 0.3.
Simultaneously with the completion of the first polymerization, the emulsifiers 0 to 5, the chain transfer agents 0 to 0.3, the polymerization initiators 0.01 to 0.3, and the redoxs 0 to 0 are respectively present at a mass ratio to the remaining monomer mixture amount of 100. 0.3, preferably emulsifiers 0 to 3, chain transfer agent 0.05 to 0.3, polymerization initiator 0.05 to 0.3, and redox at a ratio of 0.05 to 0.3. That is.
[0024]
The method for recovering a high molecular weight-containing polymer according to the method of the present invention includes, for example, cooling the obtained polymer latex to normal temperature, sulfuric acid, hydrochloric acid, an acid such as phosphoric acid, or aluminum chloride, calcium chloride, magnesium sulfate, The polymer can be precipitated by acid coagulation or salting out with an electrolyte such as a salt such as aluminum sulfate or calcium acetate, followed by filtration, washing and drying. Further, a known recovery method such as recovery of the obtained polymer latex by a technique such as spray drying or freeze drying can be used.
[0025]
The graft copolymer obtained by the production method of the present invention is dissolved in methyl ethyl ketone (MEK), and the copolymer (a) recovered from the soluble matter has a weight average molecular weight of 150,000 to 2.5 million, preferably 200,000 to 250,000. 2,000,000, more preferably 250,000 to 1.5,000,000 are obtained. Further, the ratio Mw / Mn of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is Mw / Mn ≧ 4.0, preferably Mw / Mn ≧ 5.0, more preferably Mw / Mn ≧ 6.0. Things are obtained.
Further, the copolymer (a) can be divided into two components of a main component (b) and a remaining component (c) by performing a waveform analysis by a computer of a measuring device described later. The weight average molecular weight of the main component (b) is from 80,000 to 600,000, preferably from 120,000 to 400,000, more preferably from 150,000 to 300,000. The remaining component (c) has a weight average molecular weight of 800,000 or more, preferably 1.2 million or more, and more preferably 2 million or more, and can be produced.
In addition, the method of dissolving the graft copolymer in MEK, the values of various average molecular weights, and the methods of measuring the same are those measured by the methods described below.
[0026]
The graft ratio of the graft copolymer obtained by the production method of the present invention is preferably from 30 to 100%, and can be obtained by a usual method for measuring the graft ratio described later.
[0027]
The graft copolymer of the present invention can be used alone as a resin for injection molding and extrusion molding. Further, from other aromatic vinyl-based copolymers, for example, aromatic vinyl-based monomers, vinyl cyanide-based monomers, and vinyl monomer components copolymerizable with these monomers as necessary. It is also possible to prepare a resin composition mixed with the obtained copolymer. These single resins and resin compositions are excellent in vacuum molding and blow molding properties, and exhibit excellent properties such as prevention of uneven thickness in films and sheets.
[0028]
【Example】
The present invention will be specifically described with reference to the following examples and comparative examples, but the present invention is not limited to the following examples.
[0029]
Example 1
A-1: Production of graft copolymer
(A) Production of rubbery polymer
After replacing with nitrogen in a stainless steel autoclave equipped with a stirrer, a heating / cooling device, a thermometer, a pressure gauge, and a raw material / auxiliary additive device, 3.0 parts by mass of potassium rosinate and 100 parts by mass of butadiene, and 0 parts of t-dodecyl mercaptan were used. 0.3 parts by mass, 1.5 parts by mass of dibasic sodium phosphate and 70 parts by mass of deionized water were charged, and the internal temperature was raised to 55 ° C. with stirring. When the internal temperature reached 55 ° C., 0.5 parts by mass of ammonium persulfate was added. An exotherm occurred a few minutes later, confirming the start of polymerization. When the internal pressure reached 0.1 MPa, the polymerization was terminated and cooled. The solid content concentration of the obtained rubbery polymer latex was 50%, and the average particle size of the rubber was 310 nm.
[0030]
(B) Production of graft copolymer
In a stainless steel autoclave equipped with a stirrer, a heating / cooling device, a thermometer, and a raw material / auxiliary additive device, 270 parts by mass of deionized water (including water in latex), semi-cured beef fatty acid potassium soap (KS soap manufactured by Kao Corporation) ) 1.5 parts by mass, 10.5 parts by mass of styrene, and 4.5 parts by mass of acrylonitrile were charged, and the inside of the polymerization system was replaced with nitrogen gas. 50 parts by mass (as solid content) of polymer latex were charged, and the internal temperature was raised to 50 ° C. When the internal temperature reached 48 ° C. on the way, 0.0003 parts by mass of ferrous sulfate, 0.00075 parts by mass of ethylenediaminetetraacetic acid, and 0.0225 parts by mass of formaldehyde sodium sulfoxylate were added to 10 parts by mass of deionized water. A solution having the above ratio was added, and polymerization was performed at an internal temperature of 50 ° C. for 1 hour.
Subsequently, a solution prepared by dissolving 0.0014 parts by mass of ferrous sulfate, 0.00245 parts by mass of ethylenediaminetetraacetic acid, and 0.0735 parts by mass of formaldehyde sodium sulfoxylate in 10 parts by mass of deionized water was added. After the addition, a monomer mixture consisting of 24.5 parts by mass of styrene, 10.5 parts by mass of acrylonitrile and 27 parts by mass of deionized water, 0.525 parts by mass of a higher fatty acid soap, 0.035 parts by mass of t-butyl peroxyacetate , A solution consisting of 0.035 parts by mass of α-methylstyrene dimer was continuously added, and polymerization was carried out at a temperature of 60 ° C. for 5 hours.
After the polymerization was completed, the internal temperature was cooled, and 1.5 parts by mass of an antioxidant (Irganox 1076 manufactured by Ciba Specialty Chemicals) was added to the obtained latex, and then the latex was added to an aqueous solution of magnesium sulfate heated to 95 ° C. The mixture was solidified, filtered, washed and dried to obtain a white powdery resin composition.
This graft copolymer is designated as A-1. Table 1 shows the results measured according to the respective measurement methods described below.
[0031]
Example 2
A-2: Production of graft copolymer
In a stainless steel autoclave equipped with a stirrer, a heating / cooling device, a thermometer, and a raw material / auxiliary additive device, 270 parts by mass of deionized water (including water in latex), semi-cured beef fatty acid potassium soap (KS soap manufactured by Kao Corporation) ) 2.4 parts by mass, 16.8 parts by mass of styrene, and 7.2 parts by mass of acrylonitrile were charged, and the inside of the polymerization system was replaced with nitrogen gas. 40 parts by mass (as solid content) of polymer latex were charged, and the internal temperature was raised to 50 ° C. When the internal temperature reached 48 ° C. on the way, 0.00048 parts by mass of ferrous sulfate, 0.0012 parts by mass of ethylenediaminetetraacetic acid, and 0.036 parts by mass of formaldehyde sodium sulfoxylate were added to 10 parts by mass of deionized water. A solution having the above ratio was added, and polymerization was performed at an internal temperature of 50 ° C. for 1 hour.
Subsequently, a solution prepared by dissolving 0.00144 parts by mass of ferrous sulfate, 0.00252 parts by mass of ethylenediaminetetraacetic acid, and 0.0756 parts by mass of formaldehyde sodium sulfoxylate in 10 parts by mass of deionized water was added. After the addition, a monomer mixture consisting of 25.2 parts by mass of styrene, 10.8 parts by mass of acrylonitrile, 27 parts by mass of deionized water, 0.54 parts by mass of semi-cured bovine fatty acid potassium soap, and 0.1 part of t-butyl peroxyacetate. A solution consisting of 036 parts by mass of terpinolene and 0.036 parts by mass of terpinolene was continuously added, and polymerization was conducted at a temperature of 60 ° C. for 5 hours.
After the polymerization was completed, the internal temperature was cooled, and 1.5 parts by mass of an antioxidant (Irganox 1076 manufactured by Ciba Specialty Chemicals) was added to the obtained latex, and then the latex was added to an aqueous solution of magnesium sulfate heated to 95 ° C. The mixture was solidified, filtered, washed and dried to obtain a white powdery resin composition.
This graft polymer is designated as A-2. Table 1 shows the results measured according to each of the above-described measurement methods.
[0032]
Example 3
A-3: Production of graft copolymer
In a stainless steel autoclave equipped with a stirrer, a heating / cooling device, a thermometer, and a raw material / auxiliary additive device, 270 parts by mass of deionized water (including water in latex), semi-cured beef fatty acid potassium soap (KS soap manufactured by Kao Corporation) ) 1.5 parts by mass, 11.25 parts by mass of styrene, and 3.75 parts by mass of acrylonitrile were charged, and the inside of the polymerization system was replaced with nitrogen gas. 50 parts by mass (as solid content) of polymer latex were charged, and the internal temperature was raised to 50 ° C. When the internal temperature reached 48 ° C. on the way, 0.0003 parts by mass of ferrous sulfate, 0.00075 parts by mass of ethylenediaminetetraacetic acid, and 0.0225 parts by mass of formaldehyde sodium sulfoxylate were added to 10 parts by mass of deionized water. A solution having the above ratio was added, and polymerization was performed at an internal temperature of 50 ° C. for 1 hour.
Subsequently, a solution prepared by dissolving 0.0014 parts by mass of ferrous sulfate, 0.00245 parts by mass of ethylenediaminetetraacetic acid, and 0.0735 parts by mass of formaldehyde sodium sulfoxylate in 10 parts by mass of deionized water was added. After the addition, a monomer mixture comprising 26.25 parts by mass of styrene, 8.75 parts by mass of acrylonitrile and 27 parts by mass of deionized water, 0.525 parts by mass of a higher fatty acid soap, 0.035 parts by mass of potassium persulfate, α- A solution consisting of 0.035 parts by mass of methylstyrene dimer was continuously added, and polymerization was carried out at a temperature of 60 ° C. for 5 hours.
After the polymerization was completed, the internal temperature was cooled, and 1.5 parts by mass of an antioxidant (Irganox 1076 manufactured by Ciba Specialty Chemicals) was added to the obtained latex, and then the latex was added to an aqueous solution of magnesium sulfate heated to 95 ° C. The mixture was solidified, filtered, washed and dried to obtain a white powdery resin composition.
This graft polymer is designated as A-3. Table 1 shows the results measured according to the above-described respective measurement methods.
[0033]
Example 4
A-4: Production of graft copolymer
In a stainless steel autoclave equipped with a stirrer, a heating / cooling device, a thermometer, and a raw material / auxiliary additive device, 270 parts by mass of deionized water (including water in latex), semi-cured beef fatty acid potassium soap (KS soap manufactured by Kao Corporation) ) 1.5 parts by mass, 0.0015 parts by mass of t-butyl peroxyacetate, 11.25 parts by mass of styrene, and 3.75 parts by mass of acrylonitrile, and the inside of the polymerization system was replaced with nitrogen gas. 50 parts by mass (as solid content) of the rubbery polymer latex obtained in (a) of Example 1 was charged, and the internal temperature was raised to 50 ° C. When the internal temperature reached 48 ° C. on the way, 0.0003 parts by mass of ferrous sulfate, 0.00075 parts by mass of ethylenediaminetetraacetic acid, and 0.0225 parts by mass of formaldehyde sodium sulfoxylate were added to 10 parts by mass of deionized water. The dissolved solution was added, and polymerization was performed at an internal temperature of 50 ° C. for 1 hour.
Subsequently, a solution prepared by dissolving 0.0014 parts by mass of ferrous sulfate, 0.00245 parts by mass of ethylenediaminetetraacetic acid, and 0.0735 parts by mass of formaldehyde sodium sulfoxylate in 10 parts by mass of deionized water was added. After the addition, a monomer mixture consisting of 26.25 parts by mass of styrene, 8.75 parts by mass of acrylonitrile and 27 parts by mass of deionized water, 0.525 parts by mass of a higher fatty acid soap, 0.035 parts by mass of t-butyl peroxyacetate A solution consisting of 0.035 parts by mass of n-dodecyl mercaptan was continuously added, and polymerization was carried out at a temperature of 60 ° C. for 5 hours.
After the polymerization was completed, the internal temperature was cooled, and 1.5 parts by mass of an antioxidant (Irganox 1076 manufactured by Ciba Specialty Chemicals) was added to the obtained latex, and then the latex was added to an aqueous solution of magnesium sulfate heated to 95 ° C. The mixture was solidified, filtered, washed and dried to obtain a white powdery resin composition.
This graft polymer is designated as A-4. Table 1 shows the results measured according to the above-described respective measurement methods.
[0034]
Example 5
A-5: Production of graft copolymer
In a stainless steel autoclave equipped with a stirrer, a heating / cooling device, a thermometer, and a raw material / auxiliary additive device, 270 parts by mass of deionized water (including water in latex), semi-cured beef fatty acid potassium soap (KS soap manufactured by Kao Corporation) ) 1.5 parts by mass, 0.0075 parts by mass of t-butyl peroxyacetate, 0.0075 parts by mass of α-methylstyrene dimer, 11.25 parts by mass of styrene, and 3.75 parts by mass of acrylonitrile. The mixture was replaced with a gas, and under stirring, 50 parts by mass (as a solid content) of the rubbery polymer latex obtained in (a) of Example 1 was charged, and the internal temperature was raised to 50 ° C. When the internal temperature reached 48 ° C. on the way, 0.0003 parts by mass of ferrous sulfate, 0.00075 parts by mass of ethylenediaminetetraacetic acid, and 0.0225 parts by mass of formaldehyde sodium sulfoxylate were added to 10 parts by mass of deionized water. The dissolved solution was added, and polymerization was performed at an internal temperature of 50 ° C. for 1 hour.
Subsequently, a solution prepared by dissolving 0.0014 parts by mass of ferrous sulfate, 0.00245 parts by mass of ethylenediaminetetraacetic acid, and 0.0755 parts by mass of formaldehyde sodium sulfoxylate in 10 parts by mass of deionized water was added. After the addition, a monomer mixture consisting of 26.25 parts by mass of styrene, 8.75 parts by mass of acrylonitrile and 27 parts by mass of deionized water, 0.525 parts by mass of a higher fatty acid soap, 0.035 parts by mass of t-butyl peroxyacetate And a solution consisting of 0.035 parts by mass of t-dodecyl mercaptan was added continuously, and polymerization was carried out at a temperature of 60 ° C. for 5 hours.
After the polymerization was completed, the internal temperature was cooled, and 1.5 parts by mass of an antioxidant (Irganox 1076 manufactured by Ciba Geigy) was added to the obtained latex. Subsequently, the latex was added to an aqueous solution of magnesium sulfate heated to 95 ° C. for coagulation. The mixture was filtered, washed and dried to obtain a white powdery resin composition.
This graft polymer is designated as A-5. Table 1 shows the results measured according to the above-described respective measurement methods.
[0035]
Reference Comparative Example 1
B-1: Production of graft copolymer
In a stainless steel autoclave equipped with a stirrer, a heating / cooling device, a thermometer, and a raw material / auxiliary agent adding device, 50 parts by mass (as solid content) of the rubbery polymer latex obtained in (a) of Example 1 above were removed. 270 parts by mass of ionized water (including the water content in the latex) was charged, the inside of the polymerization system was replaced with nitrogen gas, and the internal temperature was raised to 50 ° C. with stirring. When the internal temperature reaches 48 ° C. on the way, 13 parts by mass of deionized water, 0.0025 parts by mass of ferrous sulfate heptahydrate, 0.005 parts by mass of ethylenediaminetetraacetic acid tetrasodium dihydrate, 0.005 parts by mass of sodium formaldehyde A solution in which 0.3 part by mass of a sulfoxylate was dissolved was added. 35 parts by mass of styrene, 15 parts by mass of acrylonitrile and 27 parts by mass of deionized water, 1.5 parts by mass of semi-cured bovine fatty acid potassium soap, 0.2 parts by mass of diisopropylbenzene hydroperoxide, 0.25 parts by mass of α-methylstyrene dimer Part of the solution was continuously added, and polymerization was performed at a temperature of 60 ° C. for 5 hours. Thereafter, the reaction was continued at a temperature of 70 ° C. for 2 hours, and then the internal temperature was cooled. 1.5 parts of an antioxidant (Irganox 1076) was added to the obtained mixed latex, and the latex was added to an aqueous solution of magnesium sulfate heated to a temperature of 95 ° C., coagulated, filtered, washed and dried to give a white powder. A resin composition was obtained. This graft polymer is designated as B-1. Table 1 shows the results.
[0036]
Reference Comparative Example 2
B-2: Production of graft copolymer
In a stainless steel autoclave equipped with a stirrer, a heating / cooling device, a thermometer, and a raw material / auxiliary agent adding device, 50 parts by mass (as a solid content) of the rubbery polymer latex obtained in (a) of Example 1 were removed. 270 parts by mass of ionized water (including the water content in the latex) was charged, the inside of the polymerization system was replaced with nitrogen gas, and the internal temperature was raised to 50 ° C. with stirring. When the internal temperature reaches 48 ° C. on the way, 13 parts by mass of deionized water, 0.0025 parts by mass of ferrous sulfate heptahydrate, 0.005 parts by mass of ethylenediaminetetraacetic acid tetrasodium dihydrate, 0.005 parts by mass of sodium formaldehyde A solution consisting of 0.3 parts by weight of sulfoxylate was added. 35 parts by mass of styrene, 15 parts by mass of acrylonitrile and 27 parts by mass of deionized water, 1.5 parts by mass of semi-cured bovine fatty acid potassium soap, 0.1 part by mass of diisopropylbenzene hydroperoxide, 0.1 part by mass of α-methylstyrene dimer Part of the solution was continuously added, and polymerization was performed at a temperature of 60 ° C. for 5 hours. Thereafter, the reaction was continued at a temperature of 70 ° C. for 2 hours, and then the internal temperature was cooled. 1.5 parts of an antioxidant (Irganox 1076) was added to the resulting mixed latex, and the latex was added to an aqueous solution of magnesium sulfate heated to 95 ° C. to coagulate, filtered, washed and dried to give a white powder. A resin composition was obtained. This graft polymer is designated as B-2. Table 1 shows the results.
[0037]
In the production of any of the examples and the comparative examples, it was possible to carry out the method without generating abnormal heat.
[0038]
[Table 1]

[0039]
Each physical property in each example and comparative example was measured as follows.
(1) Weight average molecular weight and Mw / Mn
The weight average molecular weight of the copolymer (a) of the methyl ethyl ketone (MEK) soluble portion of the graft copolymer was measured using a gel permeation chromatography (GPC) apparatus under the following conditions. It is a polystyrene conversion value.
Apparatus; Shodex “SYSTEM-21”
Column; PLgel MIXED-B
Temperature; 40 ° C
Solvent: tetrahydrofuran
Detection; RI
Concentration: 0.2%
Injection volume; 100 μl
Calibration curve: Using a standard polystyrene (manufactured by Polymer Laboratories), the relationship between the elution time and the elution amount was converted into a molecular weight to obtain various average molecular weights.
[0040]
(A) The conditions for extracting the methyl ethyl ketone (MEK) soluble component from the graft copolymer were as follows.
About 20 g of the graft copolymer latex is precipitated and coagulated with 100 ml of methanol, and the coagulated product is subjected to suction filtration using a filter paper. The filtrate is dried at room temperature for 24 hours and in a vacuum drier for about 4 hours. About 1.2 g of the obtained sample was placed in a 100 ml Erlenmeyer flask, 30 g of methyl ethyl ketone (MEK) was added, and the mixture was stirred at a temperature of 23 ° C. for 24 hours. ) Was performed, and the mixture was allowed to stand for 30 minutes after the centrifugation operation. The operating conditions of this centrifuge were set as follows.
Temperature: -9 ° C
Rotation speed: 23,000 rpm
Time: 50 minutes
The supernatant and the precipitate of the centrifuged solution are separated, and the supernatant is poured into a 300 ml beaker containing 150 ml of methanol to precipitate the precipitate. The precipitate is suction-filtered using a filter paper. The filtrate was dried at room temperature for 24 hours, and then the residual solvent was removed by a vacuum dryer for 4 hours to obtain a sample.
[0041]
(B) Analysis of low molecular weight side of main component and high molecular weight side of minor component
The weight-average molecular weight of the methyl ethyl ketone (MEK) soluble portion of the graft copolymer is determined when the main peak on the low molecular weight side and the minor peak on the high molecular weight side can be clearly distinguished in the GPC elution curve. The weight average molecular weight and the number average molecular weight were determined by assuming a control Gaussian distribution at a position corresponding to.
In addition, when it is difficult to determine whether the secondary peak on the remaining polymer side is inconspicuous or difficult to determine, while assuming an optimal Gaussian distribution by trial and error for the tail on the high molecular weight side deviating from the Gaussian distribution assumed by the main peak, The weight-average molecular weight and the number-average molecular weight were determined.
The GPC elution curve was calculated by dividing the elution volume ml (mv) and elution time by 0.5 ml / sec. For detailed calculations, a molecular weight distribution curve and various average molecular weights were obtained using a data processor Toyo Soda SC-8020 attached to a GPC apparatus.
[0042]
(2) Method for measuring volume average particle diameter of rubber in rubber-like polymer latex
The volume average particle size of the rubbery polymer of the present invention was determined by a laser diffraction scattering method. The measurement conditions are as follows.
Apparatus: COULTER LS 230 (manufactured by COULTER)
Concentration: 2.0%
Diluent solvent: distilled water
Analysis software: Version 2.05
[0043]
(3) Method for measuring graft ratio
The graft ratio of the graft copolymer of the present invention was determined by the following method.
About 20 g of the graft copolymer latex is precipitated and coagulated with 100 ml of methanol, and the coagulated product is subjected to suction filtration using a filter paper. The filtrate is dried in a vacuum dryer for 24 hours at room temperature. About 1.2 g of the obtained sample was placed in a 100 ml Erlenmeyer flask, 30 g of methyl ethyl ketone (MEK) was added, and the mixture was stirred at a temperature of 23 ° C. for 24 hours. The centrifugation operation was performed and the mixture was allowed to stand for 30 minutes. The operating conditions of this centrifuge were set as follows.
Temperature: -9 ° C
Rotation speed: 20,000 rpm
Time: 60 minutes
The supernatant of the solution subjected to centrifugation was separated from the precipitate, and the precipitate was dried with a vacuum drier to obtain an insoluble content x. Further, the mass y of the acrylonitrile monomer quantified by the Kjeldahl nitrogen method using the sample of this insoluble matter and the mass z of the styrene monomer quantified by pyrolysis gas chromatography were determined, and the graft ratio (%) = 100 × It was calculated from the equation (y + z) / {x- (y + z)}.
[0044]
FIG. 1 shows a molecular weight distribution curve by GPC of Example 1. FIG. 2 shows a molecular weight distribution curve by GPC of Reference Comparative Example 1 which is a general method for producing a graft copolymer. As apparent from this figure, according to the production method of the present invention, the GPC molecular weight distribution curve shows a vinyl copolymer having a peak on both sides of the low molecular weight of the main component and a peak or a shoulder on the high molecular weight side, and contains a high molecular weight. Batch production of the obtained graft copolymer was able to be performed.
[0045]
【The invention's effect】
When the multi-stage polymerization was carried out according to the production method of the present invention, a graft copolymer containing the high molecular weight of the vinyl copolymer could be produced without any abnormal exothermic reaction at the time of production and by a conventional temperature control. Furthermore, since graft copolymers with various molecular weights and molecular weight distributions can be obtained, when mixed with other resins, excellent dispersibility on the high molecular weight side can be obtained. It is suitable for the heat workability of the sheet obtained, especially for vacuum formability and pressure forming.
[Brief description of the drawings]
FIG. 1 is a molecular weight distribution curve by GPC of Example 1 (A-1).
FIG. 2 is a molecular weight distribution curve by GPC of Reference Comparative Example 1 (B-1).

Claims

In the presence of 25 to 65 parts by mass of the total rubbery polymer (X), an aromatic vinyl monomer, a vinyl cyanide monomer and, if necessary, a vinyl monomer copolymerizable with these monomers. To produce a graft copolymer by polymerizing 35 to 75 parts by mass of a total monomer mixture (Y) composed of a monomer (however, X + Y = 100 parts by mass)
First, 0 to 100% by mass of the total rubbery polymer (X) and 10.0 to 60.0% by mass of the total monomer mixture (Y) are charged. Polymerized in 5 to 3 hours,
Thereafter, if necessary, the remaining rubber-like polymer is charged, and 40.0 to 90.0% by mass of the remaining monomer mixture (Y) is further charged stepwise or continuously, and the polymerization temperature is lowered. A method for producing a graft copolymer, comprising polymerizing at 40 to 90 ° C for 2 to 8 hours.

First, 0 to 100% by mass of the total rubbery polymer (X) and 10.0 to 60.0% by mass of the total monomer mixture (Y) are charged. On the other hand, the emulsifier is 100: 5 to 20 by mass, the chain transfer agent is 100: 0 to 0.1 by mass, the polymerization initiator is 100: 0 to 0.1 by mass, and the redox is 100 by mass. : After charging at a ratio of 0 to 0.3 and polymerizing at a polymerization temperature of 40 to 65 ° C for 0.5 to 3 hours,
If necessary, 100 to 0% by mass of the remaining rubber-like polymer (X) is charged, and 90.0 to 40.0% by mass of the remaining monomer mixture (Y) is gradually or continuously added. At the same time, the emulsifier and the chain transfer agent with respect to the amount of the remaining monomer mixture are 100: 0 to 5 by mass, the chain transfer agent is 100: 0 to 0.3 by mass, and the polymerization initiator is 100: 0.01 by mass. To 0.3 and redox in a mass ratio of 100: 0 to 0.3 in a stepwise or continuous manner, and polymerizing at a polymerization temperature of 40 to 90 ° C for 2 to 8 hours. Item 6. The method for producing a graft copolymer according to Item 1.

First, 100% by mass of the total rubbery polymer (X), 8 to 48% by mass of an aromatic vinyl monomer and 2 to 24% by mass of a vinyl cyanide monomer in the total monomer mixture (Y) % (10.0% by mass ≦ aromatic vinyl monomer + vinyl cyanide monomer ≦ 60.0% by mass), and an emulsifier is added to the monomer mixture amount of the first charge. 100: 5 to 20 by mass ratio, 100: 0 to 0.1 by mass ratio of chain transfer agent, 100: 0 to 0.1 by mass ratio of polymerization initiator, and 100: 0 to 0 by redox by mass ratio. 0.3 at a polymerization temperature of 40 to 65 ° C. for 0.5 to 3 hours,
At the same time as the completion, the emulsifier to the remaining monomer mixture amount is 100: 0 to 5 in mass ratio, the chain transfer agent is 100: 0 to 0.3 in mass ratio, and the polymerization initiator is 100: 0.01 to 100 in mass ratio. 0.3 and redox at a mass ratio of 100: 0 to 0.3, followed by 24-72% by mass of an aromatic vinyl monomer and 8-36% by mass of a vinyl cyanide monomer ( However, 40.0% by mass ≦ aromatic vinyl monomer + vinyl cyanide monomer ≦ 90.0% by mass) is added stepwise or continuously, and the polymerization temperature is 40 to 90 ° C. and 2 to 8%. 3. The method for producing a graft copolymer according to claim 1, wherein the polymerization is carried out for a time.

A graft copolymer obtained by the production method according to claim 1.

The weight average molecular weight of the main component (b) in the gel permeation chromatography of the copolymer (a) of the methyl ethyl ketone (MEK) soluble portion of the graft copolymer is 80,000 to 600,000, and the remaining components (c 5. The graft copolymer according to claim 4, wherein the weight average molecular weight of the above) is 800,000 or more.

The ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the copolymer (a) of the methyl ethyl ketone (MEK) soluble portion of the graft copolymer is Mw / Mn ≧ 4.0. The graft copolymer according to claim 5.