JP5044869B2 - Thermoplastic resin composition - Google Patents

Description

【００７３】
アクリロニトリル単量体単位の３連シーケンスの割合が、上記アセトン可溶分に対し１０重量％を越えると、得られる熱可塑性樹脂組成物の溶融時の色調安定性が悪くなる。上記３連シーケンスの割合は、色調安定性の点から、好ましくは８重量％未満、さらに好ましくは５重量％以下である。このようなアセトン可溶分中のアクリロニトリル単量体単位の３連シーケンスの割合が１０重量％以下に制御された熱可塑性樹脂組成物は、例えば上記のようにアクリロニトリル単量体単位の３連シーケンスの割合を１０重量％以下に制御したビニル系共重合体（Ａ）を用いることにより達成される。
【００７４】
本発明の熱可塑性樹脂組成物には、本発明の目的を損なわない範囲で塩化ビニル、ポリエチレン、ポリプロピレンなどのポリオレフィン、ナイロン６、ナイロン６６などのポリアミド、ポリエチレンテレフタレート、ポリブチレンテレフタレート、ポリシクロヘキサンジメチルテレフタレートなどのポリエステル、ポリカーボネート、各種エラストマー類を加えて成形用樹脂としての性能を改良することができる。また、必要に応じてヒンダードフェノール系、含硫黄有機化合物系、含リン有機化合物系などの酸化防止剤、フェノール系、アクリレート系などの熱安定剤、ベンゾトリアゾール系、ベンゾフェノン系、サリシレート系などの紫外線吸収剤、有機ニッケル系、ヒンダードアミン系などの光安定剤などの各種安定剤、高級脂肪酸の金属塩類、高級脂肪酸アミド類などの滑剤、フタル酸エステル類、リン酸エステル類などの可塑剤、ポリブロモジフェニルエーテル、テトラブロモビスフェノール−Ａ、臭素化エポキシオリゴマー、臭素化ポリカーボネートオリゴマーなどの含ハロゲン系化合物、リン系化合物、三酸化アンチモンなどの難燃剤・難燃助剤、帯電防止剤、カーボンブラック、酸化チタン、顔料および染料などを添加することもできる。さらに、ガラス繊維、ガラスフレーク、ガラスビーズ、炭素繊維、金属繊維などの補強剤や充填剤を添加することもできる。
【００７５】
これら添加物の添加方法については特に制限はなく、グラフト共重合体（Ｂ）とともに連続的に添加することも可能であり、またビニル系共重合体（Ａ）とグラフト共重合体（Ｂ）との混合ペレットを作成した後に後工程として添加する等の種々の方法を用いることができる。
【００７６】
かくしてなる本発明の熱可塑性樹脂組成物は、透明性、耐薬品性および色調安定性が均衡して優れ、かつ耐衝撃性、剛性などの機械的強度バランス、成形加工性およびコストパフォーマンスなどにも優れることから、家電製品、通信関連機器および一般雑貨などの用途分野で幅広く利用することができる。
【００７７】
【実施例】
本発明をさらに具体的に説明するため、以下に実施例および比較例を挙げるが、これら実施例は本発明を何ら制限するものではない。なお、ここで特に断りのない限り「％」は重量％、「部」は重量部を示す。熱可塑性樹脂組成物の樹脂特性の分析方法を下記する。
（１）ゴム質重合体の重量平均ゴム粒子径
「Rubber Age Vol.88 p.484-490 (1960), by E.Schmidt, P.H.Biddison」記載のアルギン酸ナトリウム法、即ち、アルギン酸ナトリウムの濃度によりクリーム化するポリブタジエン粒子径が異なることを利用して、クリーム化した重量割合とアルギン酸ナトリウム濃度の累積重量分率より累積重量分率５０％の粒子径を求める方法、による。
（２）グラフト共重合体（Ｂ）のグラフト率
８０℃で４時間真空乾燥を行ったグラフト共重合体（Ｂ）の所定量（ｍ；約１ｇ）にアセトン１００ｍｌを加え、７０℃の湯浴中で３時間還流し、この溶液を８８００r.p.m.（１００００Ｇ）で４０分間遠心分離した後、不溶分を濾過し、この不溶分を８０℃で４時間真空乾燥し、重量（ｎ）を測定した。グラフト率は下記式より算出した。ここでＬはグラフト共重合体のゴム含有量である。
グラフト率（％）＝｛［（ｎ）−（ｍ）×Ｌ］／［（ｍ）×Ｌ］｝×１００
【００７８】
（３）グラフト共重合体（Ｂ）の乳化剤含有量
８０℃で４時間真空乾燥を行ったグラフト共重合体（Ｂ）を約２０ｇ精秤し、１０倍量の１０％硫酸を加え、５００ｍｌビーカー中で３０分間煮沸した。これを１００メッシュの金網で濾別し、残留固形分をとり、２００ｍｌのイオン交換水中で１分間の洗浄、濾別を２回繰り返した。さらにこの固形分を２つに分けて丸底フラスコに入れ、それぞれ１００ｍｌのメタノールを加え、７０℃に設定した湯浴中３時間還流を行った。さらにこの溶液および固形分を８８００r.p.m.（１００００Ｇ）で４０分間遠心分離し、上澄み液を濾過して得られた濾液を蒸発乾固し、さらに８０℃で４時間真空乾燥して固形分を得た。この固形分をグラフト共重合体（Ｂ）に含有されていた乳化剤として精秤し、乳化剤含有量を算出した。
（４）グラフト共重合体（Ｂ）の水分率
測定サンプルを精秤し、カールフィッシャー水分計を用いて測定した。
（５）ビニル系共重合体（Ａ）の還元粘度ηｓｐ／ｃ
測定サンプルをメチルエチルケトンに溶解し、０．４ｇ／１００ｍｌメチルエチルケトン溶液として、ウベローデ粘度計を用い、３０℃で還元粘度ηｓｐ／ｃを測定した。
（６）グラフト成分（ｄ）の還元粘度ηｓｐ／ｃ
８０℃で４時間真空乾燥を行ったグラフト共重合体（Ｂ）の１ｇにアセトン２００ｍｌを加え、７０℃の湯浴中で３時間還流し、この溶液を８８００r.p.m.（１００００Ｇ）で４０分間遠心分離した後、不溶分を濾過する。濾液をロータリーエバポレーターで濃縮し、析出物を８０℃で４時間真空乾燥したものを、上記（５）と同様の方法で、０．４ｇ／１００ｍｌメチルエチルケトン溶液として、ウベローデ粘度計を用い、３０℃で還元粘度ηｓｐ／ｃを測定した。
【００７９】
（７）アセトン可溶分の単量体組成
樹脂組成物のサンプル１ｇにアセトン１００ｍｌを加え、７０℃の湯浴中で３時間還流し、この溶液を８８００r.p.m.（１００００Ｇ）で４０分間遠心分離した後、不溶分を濾過する。濾液をロータリーエバポレーターで濃縮し、析出物を８０℃で４時間真空乾燥したもの（アセトン可溶分）を用いて２２０℃に設定した加熱プレスで作成した厚み３０±５μｍのフィルムを作成した。このフィルムを試料としてＦＴ−ＩＲで分析して得られたチャートに現れた各ピークの面積から単量体組成を求めた。各単量体とピークとの対応関係は次の通りである。
メタクリル酸メチル単量体単位： エステルのカルボニル基のＣ＝Ｏ伸縮振動に帰属される１７３０ｃｍ−１のピークの倍音ピークである３４６０ｃｍ−１のピーク、
メタクリル酸単量体単位： カルボン酸のカルボニル基のＣ＝Ｏ伸縮振動に帰属される１６９０ｃｍ−１のピーク、
スチレン単量体単位： ベンゼン核の振動に帰属される１６０５ｃｍ−１のピーク、
アクリロニトリル単量体単位： −Ｃ≡Ｎ伸縮に帰属される２２４０ｃｍ−１のピーク、
（８）アセトン可溶分のφＳＴ／φＭＭＡ分布
上記（７）と同様にして得たアセトン可溶分のサンプル２ｇに、８０ｍｌのメチルエチルケトンを加え、室温で２４時間静置して溶解し、そこへシクロヘキサンを少量ずつ添加し、順次、沈殿したビニル系共重合体の重量を測定し、その沈殿物を試料として、上記（７）と同様の操作でＦＴ−ＩＲにより単量体組成を求めた。そして、サンプルとして用いたアセトン可溶分に対する沈殿物の累積重量分率と、芳香族ビニル系単量体（ａ１）含有量と不飽和カルボン酸アルキルエステル系単量体（ａ２）含有量との重量比（φＳＴ／φＭＭＡ）をプロットし、アセトン可溶分全体の平均値の０．７５〜１．２倍の範囲に含まれるアセトン可溶分の割合（重量％）を求めた。
【００８０】
（９）アセトン可溶分の酸価
樹脂組成物のサンプル１０ｇにアセトン１００ｍｌを加え、７０℃の湯浴中で３時間還流し、この溶液を８８００r.p.m.（１００００Ｇ）で４０分間遠心分離した後、不溶分を濾過する。この濾液を室温で２Ｌのメタノール中に撹拌しながら静かに注いで再沈し、上澄み液を捨てて沈殿物を得た。これをさらに２００ｍｌアセトンに溶解し、２Ｌメタノールでもう一度再沈し、得られた沈殿物を８０℃で４時間真空乾燥し、固形分（アセトン可溶分）を得た。この操作を数サンプル行って得たアセトン可溶分の約１０ｇを精秤して１００ｍｌの共栓付き三角フラスコにとり、これにアセトン４０ｍｌを加えて２時間撹拌し、均一に溶解させた。この溶液にフェノールフタレイン溶液を３滴加え、１／１０ＮのＫＯＨで中和滴定をおこなった。この滴定量を用いて、下記式に従って酸価を算出した。また、測定試料と同様に２時間撹拌したアセトンについても中和滴定を行い、これをブランクとして滴定量を補正した。
【数１】

但し、式中の値は以下の通り。
Ｘ：滴定量（ｍｌ）、Ｘ０：ブランク滴定量（ｍｌ）、Ｗ：サンプル量（ｇ）
【００８１】
（８）アセトン可溶分中のアクリロニトリル単量体単位の３連シーケンス割合
上記（７）と同じ操作により得たアセトン可溶分を試料として、¹³Ｃ−ＮＭＲに現れるアクリロニトリル単量体単位のα−炭素のシグナルシフトが隣接モノマー種の違いで若干異なることを利用し、３連シーケンスの割合をそのシグナル積分値から定量し、全単量体単位中、３連シーケンス中央のアクリロニトリル単量体単位の重量分率として表示した。測定条件は以下の通りである。
【００８２】
装置 ：ＪＥＯＬ ＪＮＭ−ＧＳＸ４００型
観測周波数 ：１００．５ＭＨｚ
溶媒 ：ＤＭＳＯ−ｄ₆
濃度 ：４４５ｍｇ／２．５ｍＬ
化学シフト基準：Ｍｅ₄ Ｓｉ
温度 ：１１０℃
観測幅 ：２００００Ｈｚ
データ点 ：３２Ｋ
flip angle ：９０°（２１μｓ）
pulsedelaytime：５．０ｓ
積算回数 ：７４００または８４００
デカップリング：gated decoupling(without NOE)
アクリロニトリルシーケンスの帰属（Ａ：アクリロニトリル、Ｓ：スチレン）
：−Ａ−Ａ−Ａ− １１８．６〜１１９．２ｐｐｍ
−Ａ−Ａ−Ｓ− １１９．３〜１２０．２ｐｐｍ
−Ｓ−Ａ−Ｓ− １２０．２〜１２１．３ｐｐｍ
【００８３】
（９）ビニル系共重合体（Ａ）中のアクリロニトリル単量体単位の３連シーケンス割合
上記アセトン可溶分の代わりにビニル系共重合体（Ａ）を試料として用いる以外は、上記（８）と同じ操作により求めた。
（１０）ビニル系共重合体（Ａ）、グラフト成分（ｄ）又はアセトン可溶分の屈折率
測定サンプルに１−ブロモナフタレンを少量滴下し、アッベ屈折計を用いて以下の条件で屈折率を測定した。
光源： ナトリウムランプＤ線、 測定温度： ２０℃
なお、グラフト成分（ｄ）のサンプルとしては上記（６）と同様にして得た析出物の真空乾燥物を用いた。
また、アセトン可溶分の測定サンプルとしては、上記（７）と同様にして得たアセトン可溶分を用いた。
【００８４】
（１１）ゴム質重合体（ｂ）の屈折率
文献から、以下の値を用いた。共重合ゴムに関しては、ＦＴ−ＩＲ、粘弾性測定等による同定を行い、各共重合成分から下記の式により共重合ゴムの屈折率（ｎＤ）を求めることができる。
ポリブタジエンの屈折率：１．５１６
ｎＤ＝１．５１６・ＭＢ＋１．５９４・ＭＳ＋１．５１６・ＭＡ
但し、式中の値は以下の通り。
ｎＤ：共重合ゴムの屈折率、ＭＢ：ブタジエン含量（ｗｔ％）、ＭＳ：スチレン含量（ｗｔ％）、ＭＡ：アクリロニトリル含量（ｗｔ％）
【００８５】
（１２）樹脂組成物の色調（ＹＩ値）
ＪＩＳ Ｋ７１０３に準拠して測定した。
（１３）樹脂組成物の透明性（全光線透過率、ヘイズ値）
８０℃熱風乾燥機中で３時間乾燥した樹脂組成物のペレットを、シリンダー温度２５０℃に設定した東芝（株）製ＩＳ５０Ａ成形機内に充填し、即時に成形した角板成形品（厚さ３ｍｍ）のヘイズ値［％］を東洋精機（株）製直読ヘイズメーターを使用して測定した。
（１４）樹脂組成物のアイゾット衝撃強度
ＡＳＴＭ Ｄ２５６（２３℃，Ｖノッチ付き）により測定した。
（１５）樹脂組成物の引張強度
ＡＳＴＭ ６３８に準拠して測定した。
【００８６】
（１６）耐薬品性
プレス成形した試験片（１２７×１２. ７×１．５ｍｍ）１２を、図２に示すように、１／４楕円治具１１に沿わして固定した後、薬剤（エタノール、イソプロパノール、又は、液体洗剤“トップ”）を成形品表面全体に塗布し、紙ワイパー（（株）クレシア製“キムワイプ”）をその上から敷き、さらに薬剤を十分紙ワイパーにしみこませる。薬剤の蒸発を抑えるためにビニール袋に１／４楕円治具１１とともに成形品をいれて密閉する。そのまま２３℃環境下で２４時間放置後、クレ−ズおよびクラックの発生有無を確認し、クラック発生点の長軸方向長（Ｘｍｍ）を測定し、下記の（式４）により臨界歪み（ε％）を算出し、その値が０．５％未満のものを×、０．５％〜１．０％のものを△、１．０％〜２．０％のものを○、２．０％を超えるものを◎と評価した。
【数２】

但し、式４および図２における符号は次のとおりである。
ε：臨界歪み（％）
ａ：治具の長軸 （ｍｍ） ［１２７ｍｍ］
ｂ：治具の短軸 （ｍｍ） ［３８ｍｍ］
ｔ：試験片の厚み（ｍｍ） ［１．５ｍｍ］
Ｘ：クラック発生点の長軸方向長（ｍｍ）
【００８７】
（参考例）グラフト共重合体
Ｂ−１： ポリブタジエンラテックス（ゴム粒子径０．３μｍ、ゲル含率８５％）５０部（固形分換算）、純水１８０部、ナトリウムホルムアルデヒドスルホキシレート０．４部、エチレンジアミン四酢酸ナトリウム０．１部、硫酸第一鉄０．０１部およびリン酸ナトリウム０．１部を反応容器に仕込み、窒素置換後６５℃に温調し、撹拌下、スチレン１１．５部、アクリロニトリル４．０部、メタクリル酸メチル３４．５部およびｎ−ドデシルメルカプタン０．３部の混合物を４時間かけて連続滴下した。同時に並行してクメンハイドロパーオキサイド０．２５部、乳化剤であるオレイン酸ナトリウム２．５部および純水２５部の混合物を５時間かけて連続滴下し、滴下終了後さらに１時間保持して重合を終了させた。
【００８８】
重合を終了して得られたラテックス状生成物を、硫酸１．０部を加えた９５℃の水２０００部中に、撹拌しながら注いで凝固させ、次いで水酸化ナトリウム０．８部で中和して凝固スラリーを得た。これを遠心分離した後、４０℃の水２０００部中で５分間洗浄し遠心分離し、６０℃の熱風乾燥機中で１２時間乾燥して、パウダー状のグラフト共重合体を調製した。得られたグラフト共重合体（Ｂ−１）のグラフト特性、グラフト成分の屈折率、乳化剤含有量及び水分率は表１に示すとおりであった。
【００８９】
Ｂ−２： 表１に示す組成のビニル系単量体混合物およびポリブタジエンラテックスを用いた以外はＢ−１と同様の方法で重合・凝固・中和・洗浄・乾燥・分離して、表１に示すグラフト共重合体（Ｂ−２）を調製した。得られたグラフト共重合体のグラフト特性、グラフト成分の屈折率、乳化剤含有量及び水分率は表１に示したとおりであった。
【００９０】
Ｂ−３： Ｂ−１と同様の方法で重合・凝固・中和した後の凝固スラリーを遠心分離した後、６０℃の水２０００部中で１０分間の洗浄し遠心分離する作業を３回繰り返し、６０℃の熱風乾燥機中で４８時間乾燥を行って、パウダー状のグラフト共重合体（Ｂ−３）を調製した。得られたグラフト共重合体のグラフト特性、グラフト成分の屈折率、乳化剤含有量及び水分率は表１に示したとおりであった。
【００９１】
［実施例１］
単量体蒸気の蒸発還流用コンデンサーおよびヘリカルリボン翼を有する２ｍ³の完全混合型重合槽と、単軸押出機型予熱機と、２軸押出機型脱モノマー機および脱モノマー機の先端から１／３長のバレル部にタンデムに接続した加熱装置を有する２軸押出機型フィーダーとからなる連続式塊状重合装置を用いて、重合及び樹脂混合を実施した。
【００９２】
まず、スチレン１７．５部、アクリロニトリル３０．０部、メタクリル酸メチル５２．５部、ｎ−オクチルメルカプタン０．１５部およびジ−ｔ−ブチルパーオキサイド０．０１部からなる単量体混合物を、１５０kg／時で重合槽に連続的に供給し、重合温度１３０℃、槽内圧０．０８ＭＰａに保って連続塊状重合させた。重合槽出における重合反応混合物の重合率は７４〜７６％の間に制御した。
【００９３】
重合反応混合物は単軸押出機型予熱機で予熱された後、２軸押出機型脱モノマー機により未反応の単量体をベント口より減圧蒸発回収し、回収した未反応単量体は連続的に重合槽へ還流させた。脱モノマー機の出口端より１／３の所で見掛け上の重合率が９９％以上に上昇したスチレン／アクリロニトリル／メタクリル酸メチル共重合体に、２軸押出機型フィーダーにより、フェノール系安定剤であるｔ−ブチルヒドロキシトルエン０．２２５kg／時、リン系の安定剤であるトリ（ノニルフェニル）ホスファイト０．２２５kg／時、及び、参考例で製造したグラフト共重合体（Ｂ−１）の半溶融状態物６０kg／時を供給し、脱モノマー機中でスチレン／アクリロニトリル／メタクリル酸メチル共重合体と溶融混練した。その溶融混練工程中、脱モノマー機の出口端より１／６の所で水を２ｋｇ／時で供給した。この水およびその他の揮発分は、さらに脱モノマー機の下流に設置したベント口より減圧蒸発させて除去した。その後溶融ポリマーをストランド状に吐出させカッターにより樹脂組成物ペレットを得た。樹脂特性評価結果を表３に示す。
【００９４】
［実施例２］
単量体混合物の組成をスチレン１７．５部、アクリロニトリル３０．０部、メタクリル酸メチル５２．５部、ｎ−オクチルメルカプタン０．１５部およびジ−ｔ−ブチルパーオキサイド０．０１部とし、加熱した２軸押出機型フィーダーより、参考例で製造したグラフト共重合体（Ｂ−２）を半溶融状態で表２に示す速度で供給した以外は実施例１と同様にして樹脂組成物ペレットを得た。樹脂特性評価結果を表３に示す。
【００９５】
［実施例３］
単量体混合物の組成をスチレン２０．０部、アクリロニトリル２０．０部、メタクリル酸メチル６０．０部、ｎ−オクチルメルカプタン０．１５部およびジ−ｔ−ブチルパーオキサイド０．０１部とし、加熱した２軸押出機型フィーダーより、参考例で製造したグラフト共重合体（Ｂ−１）を半溶融状態で表２に示す速度で供給した以外は実施例１と同様にして樹脂組成物ペレットを得た。樹脂特性評価結果を表３に示す。
【００９６】
［実施例４］
単量体蒸気の蒸発還流用コンデンサーおよびヘリカルリボン翼を有する２ｍ³の完全混合型重合槽と、単軸押出機型予熱機、および２軸押出機型脱モノマー機とからなる連続式塊状重合装置を用いて、重合を実施した。
【００９７】
まず、スチレン２０．０部、アクリロニトリル２０．０部、メタクリル酸メチル６０．０部、ｎ−オクチルメルカプタン０．１５部およびジ−ｔ−ブチルパーオキサイド０．０１部からなる単量体混合物を、１５０kg／時で重合槽に連続的に供給し、重合温度１３０℃、槽内圧０．０８ＭＰａに保って連続塊状重合させた。重合槽出における重合反応混合物の重合率は７４〜７６％の間に制御した。
【００９８】
重合反応混合物は単軸押出機型予熱機で予熱された後、２軸押出機型脱モノマー機により未反応の単量体をベント口より減圧蒸発回収し、回収した未反応単量体は連続的に重合槽へ還流させた。その後溶融ポリマーをストランド状に吐出させ、カッターによりビニル系共重合体（Ａ）ペレットを得た。
【００９９】
得られたペレット状ビニル系共重合体（Ａ）と参考例で製造したグラフト共重合体（Ｂ−１）を表２に示す割合で配合し、さらにフェノール系安定剤であるｔ−ブチルヒドロキシトルエン０．１部およびリン系の安定剤であるトリ（ノニルフェニル）ホスファイト０．１部を加えてドライブレンドした後、出口端より１／３のところに水注入設備が、出口端より１／６のところにベントが付いた４０ｍｍφ押出機を用いて、水を樹脂組成物に対して１重量％の割合で注入しながら２３０℃で溶融混練し、押出しペレタイズして樹脂組成物ペレットを得た。樹脂特性評価結果を表３に示す。
【０１００】
［実施例５］
加熱した２軸押出機型フィーダーより参考例で製造したグラフト共重合体（Ｂ−３）を半溶融状態で表２に示す速度で供給したことと、脱モノマー機への水供給を行わなかったこと以外は実施例１と同様にして樹脂組成物ペレットを得た。
樹脂特性評価結果を表３に示す。
【０１０１】
［比較例１］
単量体混合物の組成をスチレン２４．０部、アクリロニトリル５．０部、メタクリル酸メチル７１．０部、ｎ−オクチルメルカプタン０．１５部およびジ−ｔ−ブチルパーオキサイド０．０１部とし、加熱した２軸押出機型フィーダーより、参考例で製造したグラフト共重合体（Ｂ−１）を半溶融状態で表２に示す速度で供給した以外は実施例１と同様にして樹脂組成物ペレットを得た。樹脂特性評価結果を表３に示す。
【０１０２】
［比較例２］
単量体混合物の組成をスチレン１０．０部、アクリロニトリル６０．０部、メタクリル酸メチル３０．０部、ｎ−オクチルメルカプタン０．１５部およびジ−ｔ−ブチルパーオキサイド０．０１部とし、加熱した２軸押出機型フィーダーより、参考例で製造したグラフト共重合体（Ｂ−１）を半溶融状態で表２に示す速度で供給した以外は実施例１と同様にして樹脂組成物ペレットを得た。樹脂特性評価結果を表３に示す。
【０１０３】
【表１】

【０１０４】
【表２】

【０１０５】
【表３】

実施例１〜５のとおり、本発明で特定した熱可塑性樹脂組成物は、透明性、色調安定性および耐薬品性のすべてにおいて均衡に優れていることがわかる。また特に、実施例１〜３についてはビニル系共重合体（Ａ）とグラフト共重合体（Ｂ）の混合方法およびアセトン可溶分中の酸価が前述の好ましい範囲にあるため、特に透明性、色調、耐衝撃性及び剛性において物性バランスが良く、優れたものであった。
【０１０６】
しかし、比較例１、２で得られた樹脂組成物は、ビニル系共重合体（Ａ）を構成する単量体組成および、アセトン可溶分中のアクリロニトリル３連シーケンス割合が本発明の範囲外であったため、透明性、色調安定性および耐薬品性のいずれかが劣るものであった。
【０１０７】
【発明の効果】
本発明の熱可塑性樹脂組成物は、透明性、耐薬品性および色調安定性が均衡して優れ、かつ耐衝撃性、剛性などの機械的強度バランス、成形加工性およびコストパフォーマンスなどにも優れ、これら特性を生かして、家電製品、通信関連機器および一般雑貨などの用途分野で幅広く利用することができる。
【図面の簡単な説明】
【図１】 本発明の樹脂組成物を、連続塊状重合し樹脂混合する方法により製造する際の装置の一実施態様を示す装置縦断面概略図である。
【図２】 耐薬品性の評価に使用する１／４楕円治具、及びその使用方法を説明する縦断面図である。
【符号の説明】
１： 反応槽
２： 予熱機
３： 二軸押出機型脱モノマー機
４： 溶融混練域
５： 二軸押出機型フィーダー
１１： １／４楕円治具
１２： 試験片
１３： 薬液塗布面
１４： クラック
Ｘ： クラック発生箇所からの距離[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rubber-containing styrene-based thermoplastic resin composition having transparency, and more specifically, a rubber-containing styrene-based thermoplastic resin composition having excellent balance of transparency, chemical resistance and color stability. It is about things.
[0002]
[Prior art]
Transparent ABS resin comprising a graft copolymer obtained by copolymerizing a rubbery polymer such as a diene rubber with an aromatic vinyl compound such as styrene or α-methylstyrene, or a vinyl cyanide compound such as acrylonitrile or methacrylonitrile. Is excellent in transparency, impact resistance, mechanical strength balance such as rigidity, molding processability and cost performance, and is widely used in application fields such as home appliances, communication equipment and general goods.
[0003]
However, the use of such transparent ABS resins is limited due to their low resistance to chemicals such as organic solvents and solvents such as detergents.
[0004]
As a means for improving the chemical resistance of a general ABS resin having no transparency, it is generally known to increase the content of vinyl cyanide compound, and various so-called high nitrile-containing thermoplastic resin compositions have been proposed. ing.
[0005]
For example, in terms of improving chemical resistance, a resin composition (JP-A-4-258619, JP-A-5-78428) defining a graft ratio of a graft copolymer, and a methacrylic acid ester as a matrix component are used. A high nitrile-containing thermoplastic resin composition as an essential component (Japanese Patent Laid-Open No. 4-126756) is known.
[0006]
However, in the conventional high nitrile-containing thermoplastic resin composition described above, it is difficult to obtain a polymer having a uniform composition because the reaction rate of the aromatic vinyl compound and the vinyl cyanide compound is different. For this reason, a thermoplastic resin composition containing a copolymer composed of an aromatic vinyl compound and a vinyl cyanide compound tends to be colored yellow at the time of molding, and the quality is deteriorated due to discoloration.
[0007]
As described above, the chemical resistance improvement technology due to the high nitrile tends to cause the problem of discoloration and transparency deterioration due to the high nitrile, and if this high nitrile technology is applied to transparent ABS, it becomes a fatal defect for transparent resin products. It has been considered in the past.
[0008]
Therefore, a high nitrile-containing thermoplastic resin composition having an excellent balance of transparency, chemical resistance and color tone stability has not been obtained.
[0009]
[Problems to be solved by the invention]
The present invention has been achieved as a result of studying the above-described problems in the prior art as an object, and is a rubber-containing styrene-based thermoplastic resin composition having excellent balance of transparency, chemical resistance and color stability. The purpose is to provide goods.
[0010]
[Means for Solving the Problems]
As a result of intensive studies to achieve the above object, the inventors of the present invention have developed a rubber-containing graft polymer into a vinyl copolymer obtained by polymerizing a vinyl monomer mixture using a specific method. When preparing a dispersed thermoplastic resin composition, if a specific condition is satisfied, the thermoplastic resin composition is excellent in transparency, chemical resistance, and color stability by satisfying specific physical properties. As a result, the inventors have found that a product can be obtained.
[0011]
  That is, the present inventiontransparencyThe thermoplastic resin composition comprises an aromatic vinyl monomer (a1) 5 to 40% by weight, an unsaturated carboxylic acid alkyl ester monomer (a2) 30 to 80% by weight, a vinyl cyanide monomer (a3). Vinyl) obtained by continuous bulk polymerization or continuous solution polymerization of a vinyl monomer mixture (a) containing 10 to 50% by weight and other monomers copolymerizable with these (a4) 0 to 40% by weight A graft copolymer (B) obtained by graft polymerization of one or more vinyl monomers (c) in the presence of the rubbery polymer (b) is dispersed in the copolymer (A). A thermoplastic resin composition comprising:The solubility parameter of the vinyl copolymer (A) is 10.5 to 12.5 (cal / ml) ^1/2 AndThe ratio of the triple sequence of acrylonitrile monomer units present in the acetone-soluble component of the thermoplastic resin composition is 10% by weight or less based on the acetone-soluble component.
[0012]
  In the present invention,transparencyIn the thermoplastic resin composition, the haze value is 30% or less, and the difference in refractive index between the rubbery polymer component constituting the graft copolymer (B) and the acetone-soluble component is 0.03. Be within,PreviousThe acid value of the acetone-soluble component is 0.01 to 1 mg KOH / g, the vinyl monomer mixture (a) and the vinyl monomer mixture (c) are unsaturated carboxylic acid monomers ( However, it contains substantially no unsaturated carboxylic acid alkyl ester monomer (a2)) (a5), and a vinyl copolymer (A) is produced by continuous bulk polymerization or continuous solution polymerization. Production of a thermoplastic resin composition by adding the graft copolymer (B) to the molten vinyl copolymer (A) and melt mixing, polymerization of the vinyl monomer mixture (a) In the middle of the demonomer process in the process of producing the vinyl copolymer (A) by performing demonomer subsequent to or after the demonomer process, the graft copolymer is added to the molten vinyl copolymer (A). Adding coalescence (B) And the graft copolymer (B) when added to the vinyl copolymer (A) is in a semi-molten or molten state, both of which are mentioned as preferable conditions. The acquisition of an excellent effect can be expected.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, specific examples of the aromatic vinyl monomer (a1) used for the vinyl copolymer (A) include styrene, α-methyl styrene, p-methyl styrene, vinyl toluene, and t-butyl styrene. , O-ethylstyrene, o-chlorostyrene, o, p-dichlorostyrene, and the like, among which styrene and α-methylstyrene are particularly preferable. These can use 1 type (s) or 2 or more types.
[0014]
In the vinyl monomer mixture (a) forming the vinyl copolymer (A), the aromatic vinyl monomer (a1) is contained in an amount of 5 to 40% by weight, preferably 10 to 30% by weight. Need to use. If it is less than the above range, mechanical properties such as Izod impact strength and rigidity are remarkably deteriorated, and if it exceeds the above range, transparency tends to be remarkably deteriorated.
[0015]
In the present invention, specific examples of the unsaturated carboxylic acid alkyl ester monomer (a2) used for the vinyl copolymer (A) include methyl (meth) acrylate, ethyl (meth) acrylate, (meth ) N-propyl acrylate, n-butyl (meth) acrylate, t-butyl (meth) acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, chloromethyl (meth) acrylate and ( Examples thereof include 2-chloroethyl (meth) acrylate, and methyl methacrylate is particularly preferable. These can use 1 type (s) or 2 or more types.
[0016]
In the vinyl monomer mixture (a) forming the vinyl copolymer (A), the unsaturated carboxylic acid alkyl ester monomer (a2) is 30 to 80% by weight, preferably 35 to 75% by weight. It is necessary to use in the range. If it is less than the above range, it is difficult to obtain transparency, and if it exceeds the above range, chemical resistance tends to be remarkably lowered.
[0017]
In the present invention, specific examples of the vinyl cyanide monomer (a3) used for the vinyl copolymer (A) include acrylonitrile, methacrylonitrile and ethacrylonitrile, with acrylonitrile being particularly preferred. These can use 1 type (s) or 2 or more types.
[0018]
In the vinyl monomer mixture (a) forming the vinyl copolymer (A), the vinyl cyanide monomer (a3) is in the range of 10 to 50% by weight, preferably 12 to 40% by weight. Need to use. If it is less than the above range, the chemical resistance is remarkably lowered, and if it exceeds the above range, desirable color tone stability tends not to be obtained.
[0019]
In the present invention, the copolymerizable monomer (a4) used for the vinyl copolymer (A) is not particularly limited, but N-methylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, and the like And an unsaturated amide such as acrylamide. Among them, N-phenylmaleimide is preferably used. These can use 1 type (s) or 2 or more types.
[0020]
The vinyl-based monomer mixture (a) substantially contains an acidic monomer such as an unsaturated carboxylic acid-based monomer (excluding the unsaturated carboxylic acid alkyl ester-based monomer (a2)) (a5). It is especially preferable not to contain it in order to adjust the acid value of the acetone-soluble component in the thermoplastic resin composition and to improve the color tone. Here, “substantially not containing” means that these acidic monomers are not intentionally added as a monomer mixture. For example, 0.01% or more with respect to the monomer mixture (a). Addition can be considered intentional addition. The unsaturated carboxylic acid derived from impurities in each monomer of the monomer mixture (a), for example, 0.01 contained as an impurity in the unsaturated carboxylic acid alkyl ester monomer (a2). Less than% unsaturated carboxylic acids are not intentionally added. Examples of the unsaturated carboxylic acid monomer (a5) include acrylic acid and methacrylic acid.
[0021]
In the vinyl monomer mixture (a) forming the vinyl copolymer (A), the other copolymerizable monomer (a4) can be used in the range of 0 to 40% by weight. From the viewpoint of properties, it can be used in the range of 0 to 30% by weight.
[0022]
The effect of the present invention is remarkable when applied to a thermoplastic resin composition having a haze value of preferably 30% or less, more preferably 15% or less.
[0023]
  The vinyl monomer mixture (a) has a solubility parameter of the vinyl copolymer (A) of 10.5 to 12.5 (cal / ml).^1/2Select the composition of each monomer so thatTheThe definition of the solubility parameter here is shown in the following (Formula 1).
[0024]
  δ = (ΣΔEi · X / ΣΔVm · X)^1/2          (Formula 1)
  δ: solubility parameter ((cal / ml) of vinyl copolymer (A)^1/2)
  X: molar fraction (%) of the copolymer component constituting the vinyl copolymer (A)
  ΔEi: Evaporation energy (cal / mol) of the copolymer component constituting the vinyl copolymer (A)
  ΔVm: Molecular capacity of the copolymer component constituting the vinyl copolymer (A) (ml / mol)
  The above (Equation 1) and the numerical values of ΔEi and ΔVm are as follows. Burrell, Offic. Dig. A. J. et al. Tortorello, M.M. A. Kinsella, J. et al. Coat. Technol. Quoted from. From the viewpoint of chemical resistance and mechanical properties of the thermoplastic resin composition, the solubility parameter of the vinyl copolymer (A)Is10.5 to 12.5 (cal / ml)^1/2 AndPreferably, 10.7 to 12.3 (cal / ml)^1/2It is.
[0025]
In the present invention, the acid value of the acetone-soluble component contained in the thermoplastic resin composition is preferably 0.01 to 1 mg KOH / g from the viewpoints of transparency, impact resistance, rigidity, and color tone stability. .
[0026]
Further, the composition distribution of the weight ratio (φST / φMMA) of the aromatic vinyl monomer (a1) and the unsaturated carboxylic acid alkyl ester monomer (a2) in the monomer composition constituting the acetone-soluble component. In which the portion of 80% by weight or more of the acetone-soluble component is contained within the range of 0.75 to 1.2 times the average value of the weight ratio (φST / φMMA) It is preferable in order to suppress a decrease in transparency of the thermoplastic resin composition when an acid component due to hydrolysis or the like of the system monomer (a2) is contained. Moreover, it is more preferable that 90 weight% or more is contained in the range of 0.75 to 1.2 times the average value, and it is most preferable that it is 95 weight% or more.
[0027]
The monomer composition of acetone-soluble component is aromatic vinyl monomer (a1) 5 to 40% by weight, unsaturated carboxylic acid alkyl ester monomer (a2) 30 to 80% by weight, vinyl cyanide When the monomer (a3) is 10 to 50% by weight and the other monomer (a4) copolymerizable with these is 0 to 40% by weight, the transparency, color tone, impact resistance, etc. of the resin composition are further improved. It is preferable because it can be excellent in balance.
[0028]
What is necessary is just to determine | assay and determine the composition of the said acetone soluble part by the following peak which appears in a FT-IR chart.
Aromatic vinyl monomer (a1): peak at 1605 cm −1 attributed to vibration of the benzene nucleus,
Unsaturated carboxylic acid alkyl ester monomer (a2): peak at 1730 cm −1 attributed to C═O stretching vibration of the carbonyl group of the ester,
Vinyl cyanide monomer (a3): peak at 2240 cm−1 attributed to —C≡N stretching
The acetone-soluble component is mainly composed of a resin component derived from the vinyl copolymer (A), but the copolymer polymerized from the vinyl monomer mixture (c) in the graft copolymer (B). A part of the resin component derived from the part is also included. Therefore, in order to control the composition of the acetone-soluble component within the above-mentioned predetermined range, it is effective to control the composition of the vinyl-based copolymer (A) constituting the main component within the above-mentioned predetermined range. Furthermore, it is preferable to control the composition of the copolymer portion polymerized from the vinyl monomer mixture (c) within the predetermined range.
[0029]
Further, the composition distribution condition of (φST / φMMA) in the acetone-soluble component, that is, the aromatic vinyl monomer (a1) and the unsaturated carboxylic acid alkyl ester monomer (a2) constituting the acetone-soluble component. A ratio of 80 wt% or more of the acetone-soluble component is included in the range of 0.75 to 1.2 times the average value of the weight ratio (φST / φMMA). This means that the composition distribution of the solute is narrow, and this composition distribution condition is preferable in order to further increase the transparency of the resulting thermoplastic resin composition.
[0030]
In the thermoplastic resin composition of the present invention, it is preferable that a small amount of copolymerized acid component is present in the matrix resin because it gives better physical properties. That is, the acid value of the acetone-soluble component in the resin composition part is preferably 0.01 to 1 mg KOH / g from the viewpoint of impact resistance, rigidity, and color tone. From the viewpoint of color tone and physical property balance, it is more preferably 0.012 to 0.5 mgKOH / g, and particularly preferably 0.015 to 0.1 mgKOH / g.
[0031]
The method for controlling the acid value in the present invention is not particularly limited, but from the viewpoint of minimizing the deterioration of the color tone of the resulting thermoplastic resin composition, the vinyl copolymer (A) The vinyl monomer mixture (a) which is the raw material and / or the vinyl monomer mixture (c) which is the raw material of the rubber-containing graft copolymer (b) is converted into an unsaturated carboxylic acid monomer (unsaturated). It contains substantially no acidic monomer such as (a5) except for the saturated carboxylic acid alkyl ester monomer (a2), and the unsaturated carboxylic acid alkyl ester monomer (a2) during the process. It is particularly preferable to control the acid value within a predetermined range by hydrolyzing the acid. Among them, the vinyl monomer mixture (a) and the vinyl monomer mixture (c) are both unsaturated carboxylic acid monomers (excluding unsaturated carboxylic acid alkyl ester monomers (a2)). It is particularly preferable that an acidic monomer such as (a5) is not substantially contained.
[0032]
Although there is no restriction | limiting in particular about the refractive index of the acetone soluble part of the thermoplastic resin composition in this invention, From the point of transparency of a thermoplastic resin composition, a refractive index is substantially rubber-like polymer (b) and Preferably they are the same or close. As a specific range, it is preferable to suppress the difference in refractive index between the vinyl copolymer (A) and the rubbery polymer (b) to 0.03 or less, and more preferably 0.01 or less.
[0033]
The reduced viscosity (ηsp / c) of the vinyl copolymer (A) in the present invention is not particularly limited, but is in the range of 0.1 to 1.0 dl / g, particularly 0.2 to 0.7 dl / g. It is preferable from the viewpoint of the balance between impact resistance and moldability.
[0034]
In the composition distribution of the weight ratio (φST / φMMA) of the aromatic vinyl monomer (a1) and the unsaturated carboxylic acid alkyl ester monomer (a2) in the vinyl copolymer (A), It is preferable that a portion of 80% by weight or more of the vinyl copolymer (A) is contained within a range of 0.75 to 1.2 times the average value of the weight ratio (φST / φMMA).
[0035]
In order to control the transparency and color stability of the resulting thermoplastic resin composition and to control the properties of the thermoplastic resin composition to a predetermined value, the method for polymerizing the vinyl copolymer (A) in the present invention For this, continuous bulk polymerization or continuous solution polymerization is used.
[0036]
In the present invention, the method of performing continuous bulk polymerization or continuous solution polymerization in the step of producing a vinyl copolymer (A) by copolymerizing the vinyl monomer mixture (a) is not particularly limited, and any method may be used. For example, after polymerization in a polymerization tank, a method of demonomerization (desolvation / devolatilization) can be employed.
[0037]
As the polymerization tank, there are various mixing blades such as paddle blades, turbine blades, propeller blades, bull margin blades, multistage blades, anchor blades, max blend blades, double helical blades, etc. A tower reactor or the like can be used. In addition, a multi-tube reactor, a kneader reactor, a twin screw extruder, or the like can also be used as the polymerization reactor (for example, assessment 10 of polymer production process “assessment of impact polystyrene”, Polymer Society, 1989 (See the January 26th issue). These polymerization tanks (reactors) are used in one (tank) or two (tank) or more, and may be used by combining two or more reactors as necessary. Among them, two or less (tank) are preferable from the viewpoint of narrowing the composition distribution of the acetone-soluble component of the thermoplastic resin composition to be obtained and suppressing the triple sequence ratio of the acrylonitrile monomer unit. In particular, a single tank type complete mixing type polymerization tank is preferably selected.
[0038]
The reaction mixture obtained by polymerization in these polymerization tanks or reactors is usually then subjected to a demonomer process to remove monomers, solvents and other volatile components. As a method for removing the monomer, a uniaxial or biaxial extruder having a vent is used to remove volatile components from a vent hole under normal pressure or reduced pressure, and a plate fin type heater such as a centrifugal type is incorporated in the drum. The method of removing volatile components with an evaporator, the method of removing volatile components with a thin-film evaporator such as a centrifugal type, the residual heat using a multi-tube heat exchanger, foaming and flushing to a vacuum chamber to remove volatile components Any of these methods can be used, but a single or twin screw extruder having a vent is particularly preferably used.
[0039]
FIG. 1 is an apparatus longitudinal cross-sectional schematic view showing an embodiment of an apparatus for carrying out the method of the present invention by a continuous bulk polymerization and resin mixing method. In order, the vinyl monomer (a) is continuously bulk polymerized. A reaction vessel (1) for producing a vinyl copolymer (A), a preheater (2) for raising the temperature of the vinyl copolymer (A) obtained by polymerization to a predetermined temperature, And a twin-screw extruder type demonomer machine (3) having a vent port (31) for demonomer connection. Further, the graft copolymer (B) is added in tandem to the demonomer machine. A twin screw extruder type feeder (5) is connected.
[0040]
In FIG. 1, the reaction product continuously supplied from the reaction vessel (1) is heated by the preheater (2), then supplied to the twin-screw extruder type demonomer (3), and 150 Volatile components such as monomers are removed out of the system from the vent port (31) at about 280 ° C under normal pressure or reduced pressure. The removal of the volatile component is performed until the amount of the unreacted monomer reaches a predetermined amount, for example, 10% by weight or less, more preferably 5% by weight or less.
[0041]
In FIG. 1, an addition port from the feeder (5) is opened at a position near the downstream side in the middle of the demonomer machine (3), and the graft copolymer has a predetermined temperature (for example, about 100 to 220 ° C.). (B) is added into the system. In order to improve the mixing state, the feeder (5) is provided with a heating device, and the graft copolymer (B) to be added is heated to a predetermined temperature in a semi-molten or molten state. preferable. For example, it is preferably composed of a screw, a cylinder, and a screw driving unit, and the cylinder preferably has a device structure having heating / cooling functions. Further, as this feeder, a uniaxial or biaxial extruder type feeder having a heating device can be used.
[0042]
At the position where the supply port of the graft copolymer (B) is connected, the content of the unreacted monomer is reduced to 10% by weight or less, more preferably 5% by weight or less. This is preferable in order to prevent thermal deterioration of the rubber component during the operation of removing the unreacted monomer.
[0043]
After the vinyl copolymer (A) and the graft copolymer (B) are melt-mixed in the melt-kneading zone (4) of the twin-screw extruder type demonomer (3), from the discharge port (6) The resin composition is discharged out of the system.
[0044]
Further, it is preferable to provide a water injection port (41) in the melt-kneading zone (4) and add a predetermined amount of water, and the injected water and residual monomer are removed from the vent port (42) provided further downstream. Devised.
[0045]
In the continuous bulk polymerization or solution polymerization of the vinyl copolymer (A), thermal polymerization without using an initiator, initiator polymerization using an initiator, thermal polymerization and initiator polymerization can be performed. It can also be used in combination. As the initiator, a peroxide or an azo compound is used.
[0046]
Specific examples of the peroxide include benzoyl peroxide, cumene hydroperoxide, dicumyl peroxide, diisopropylbenzene hydroperoxide, t-butyl hydroperoxide, t-butyl cumyl peroxide, t-butyl peroxyacetate, t-butyl peroxybenzoate, t-butyl peroxyisopropyl carbonate, di-t-butyl peroxide, t-butyl peroctate, 1,1-bis (t-butylperoxy) 3,3,5-trimethyl Examples include cyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, t-butylperoxy-2-ethylhexanoate, and the like. Of these, cumene hydroperoxide and 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane are particularly preferably used. Specific examples of the azo compound include azobisisobutyronitrile, azobis (2,4dimethylvaleronitrile), 2-phenylazo-2,4-dimethyl-4-methoxyvaleronitrile, 2-cyano-2-propylazoformamide. 1,1'-azobiscyclohexane-1-carbonitrile, azobis (4-methoxy-2,4-dimethylvaleronitrile), dimethyl 2,2'-azobisisobutyrate, 1-t-butylazo-1- And cyanocyclohexane, 2-t-butylazo-2-cyanobutane, 2-t-butylazo-2-cyano-4-methoxy-4-methylpentane, and the like. When using these initiators, they are used alone or in combination of two or more. Of these, 1,1′-azobiscyclohexane-1-carbonitrile is particularly preferably used.
[0047]
Chain transfer agents such as mercaptans and terpenes can be used for the purpose of adjusting the degree of polymerization of the vinyl copolymer (A). Specific examples thereof include n-octyl mercaptan, t-dodecyl mercaptan, n- Examples include dodecyl mercaptan, n-tetradecyl mercaptan, n-octadecyl mercaptan, and terpinolene. When using these chain transfer agents, they are used alone or in combination of two or more. Of these, n-octyl mercaptan, t-dodecyl mercaptan, and n-dodecyl mercaptan are particularly preferably used.
[0048]
When the vinyl copolymer (A) is produced by a continuous solution polymerization method, the amount of the solvent is not particularly limited. However, from the viewpoint of productivity, it is preferably 30% by weight or less, more preferably based on the polymerization solution. A solvent amount of 20% by weight or less is used. The solvent to be used is not particularly limited, but ethylbenzene or methyl ethyl ketone is preferable from the viewpoint of polymerization stability, and ethylbenzene is particularly preferable.
[0049]
The rubbery polymer (b) used for the graft copolymer (B) in the present invention is not particularly limited, but specific examples include polybutadiene, poly (butadiene-styrene), poly (butadiene-acrylonitrile), poly Isoprene, poly (butadiene-butyl acrylate), poly (butadiene-methyl methacrylate), poly (butyl acrylate-methyl methacrylate), poly (butadiene-ethyl acrylate), ethylene-propylene rubber, ethylene-propylene-diene rubber , Poly (ethylene-isoprene), and poly (ethylene-methyl acrylate). These rubbery polymers (b) are used in one kind or a mixture of two or more kinds. Among these, use of polybutadiene, poly (butadiene-styrene), poly (butadiene-acrylonitrile), and ethylene-propylene rubber is preferable in terms of impact resistance.
[0050]
Further, the content of the rubbery polymer (b) constituting the graft copolymer (B) is not particularly limited, but is preferably in the range of 20 to 80 parts by weight, particularly 35 to 60 parts by weight, If the amount is less than parts by weight, the impact strength of the resulting thermoplastic resin composition is lowered, and if it exceeds 80 parts by weight, the melt viscosity is increased and the moldability is deteriorated.
[0051]
The rubber polymer (b) has a weight average particle diameter of 0.1 to 1.5 μm, preferably 0, from the viewpoint of impact resistance, molding processability, fluidity and appearance of the thermoplastic resin composition obtained. The range is from 15 to 1.2 μm.
[0052]
The composition of the vinyl monomer mixture (c) that is a polymerization raw material of the graft component (d) of the graft copolymer (B) is not particularly limited, but the color tone and impact resistance of the resulting thermoplastic resin composition Aromatic vinyl monomer (a1) 5 to 40% by weight, unsaturated carboxylic acid alkyl ester monomer (a2) 30 to 80% by weight, vinyl cyanide monomer It is preferable to contain 10 to 50% by weight of the body (a3) and 0 to 40% by weight of another monomer (a4) copolymerizable therewith. The monomer composition constituting the vinyl monomer mixture (c) may be the same as or different from the vinyl monomer mixture (a) constituting the vinyl copolymer (A). .
[0053]
Further, in this vinyl monomer mixture (c), as in the case of the vinyl monomer mixture (a) as a polymerization raw material of the styrene copolymer, an unsaturated carboxylic acid monomer (but unsaturated) is used. Substantially no acidic monomer such as (a5) except for the carboxylic acid alkyl ester monomer (a2) makes the acid value of the acetone-soluble component in the thermoplastic resin composition a desired level. Therefore, it is particularly preferable for improving the color tone. Here, “substantially not containing” is the same as in the case of the vinyl monomer mixture (a) as a polymerization raw material of the styrene copolymer.
[0054]
From the transparency point of the thermoplastic resin composition obtained, the refractive index of the graft component (d) of the graft copolymer (B) is substantially the same as or slightly different from the refractive index of the rubbery polymer (b). Thus, it is preferable to adjust the composition of the vinyl monomer mixture (c). As a specific range, the difference in refractive index between the graft component (d) and the rubbery polymer (b) is preferably suppressed to 0.03 or less, more preferably 0.01 or less.
[0055]
The graft copolymer (B) can be used alone or in combination of two or more. When two or more kinds of blends are used, the rubbery polymer (b) and graft component (d) contained in each component are used. It is preferable from the viewpoint of the transparency of the thermoplastic resin to be prepared so that the refractive index of
[0056]
The reduced viscosity (ηsp / c) of the graft component constituting the graft copolymer (B) in the present invention is not particularly limited, but is 0.05 to 1.2 dl / g, particularly 0.1 to 0.7 dl / g. It is preferable from the viewpoint of the balance between impact resistance and moldability.
[0057]
Although there is no restriction | limiting in the grafting rate of a graft copolymer (B), 5 to 150 weight% from the point of impact resistance, Preferably the thing of 10 to 100 weight% is used.
[0058]
The method of graft polymerization at the time of producing the graft copolymer (B) is not limited, but can be produced by any method such as a known emulsion polymerization method, suspension polymerization method, continuous bulk polymerization method, continuous solution polymerization method, etc. Is produced by emulsion polymerization or bulk polymerization. Among them, in order to suppress the deterioration and coloring of the rubber component due to excessive heat history, and the hydrolysis of the unsaturated carboxylic acid alkyl ester monomer (a2) in the melt-kneading step with the vinyl copolymer (A). In order to control the decomposition, it is most preferable to be produced by an emulsion polymerization method from the viewpoint that the emulsifier content and the water content in the graft copolymer (B) can be easily adjusted.
[0059]
Normal emulsion polymerization involves emulsion graft polymerization of the monomer mixture in the presence of a rubbery polymer latex. There is no particular limitation on the emulsifier used in this emulsion graft polymerization, and various surfactants can be used, but anionic surfactants such as carboxylate type, sulfate ester type and sulfonate type are particularly preferably used. The
[0060]
Specific examples of such emulsifiers include caprylate, caprate, laurate, myristate, palmitate, stearate, oleate, linoleate, linolenate, rosinate, Behenate, castor oil sulfate, lauryl alcohol sulfate, other higher alcohol sulfate, dodecylbenzene sulfonate, alkyl naphthalene sulfonate, alkyl diphenyl ether disulfonate, naphthalene sulfonate condensate, Examples thereof include dialkyl sulfosuccinate, polyoxyethylene lauryl sulfate, polyoxyethylene alkyl ether sulfate, and polyoxyethylene alkyl phenyl ether sulfate. The salt here is an alkali metal salt, an ammonium salt or the like, and specific examples of the alkali metal salt include potassium salt, sodium salt, lithium salt and the like. Among these, potassium salt and sodium salt of palmitic acid, stearic acid, oleic acid are preferably used for controlling hydrolysis. These emulsifiers are used alone or in combination of two or more.
[0061]
Examples of the initiator and chain transfer agent that can be used in the emulsion graft polymerization include the initiator and chain transfer agent mentioned in the production of the vinyl copolymer (A), and the initiator is also used in a redox system. Is done.
[0062]
The graft copolymer (B) produced by emulsion graft polymerization is then recovered by adding a coagulant to coagulate the latex and then recovering the graft copolymer (B). Acid or water-soluble salt is used as the coagulant, and specific examples thereof include sulfuric acid, hydrochloric acid, phosphoric acid, acetic acid, calcium chloride, magnesium chloride, barium chloride, aluminum chloride, magnesium sulfate, aluminum sulfate, aluminum ammonium sulfate, sulfuric acid Examples include aluminum potassium and sodium aluminum sulfate. These coagulants are used in one or a mixture of two or more. The graft copolymer (B) slurry obtained by coagulating the latex can be used as it is or after passing through a dehydration / washing process, and can be used in the form of a slurry or a water-containing cake. It is preferable from the point of the handleability in a process to make it into a powder form through a process and to add to the vinyl-type copolymer (A) in a molten state by this powder form.
[0063]
When added to the vinyl copolymer (A), the amount of emulsifier contained in the material on the graft copolymer (B) side is determined by the hydrolysis of the unsaturated carboxylic acid ester monomer (a2) during the process. In order to control the reaction and make the acid value of the acetone soluble part of the thermoplastic resin composition obtained within the predetermined range of the present invention, 0.1 to 5% by weight is preferable, particularly 0.15 to 2% by weight. Is preferred. Conventionally, since it has not been obtained that an emulsifier can be used for inhibiting hydrolysis of a polymer, it has been considered that an emulsifier should be excluded from a resin product as much as possible. However, in the present invention, it is effective to actively contain an emulsifier within the above range as an effective means for controlling the acid value of the acetone-soluble component of the thermoplastic resin composition within the predetermined range. .
[0064]
There is no particular limitation on the method for adjusting the emulsifier content in the graft copolymer (B) within a predetermined range. For example, the number of times of dehydration and washing of the slurry-like graft copolymer (B) after coagulation, washing It is possible to adjust to the target emulsifier content by controlling the temperature and amount of water. In addition, for example, an emulsifier may be added separately to the graft copolymer (B) for adjustment.
[0065]
The amount of water (water content) contained in the graft copolymer (B) when added to the vinyl copolymer (A) is the amount of the unsaturated carboxylic acid ester monomer (a2) in the process. In order to control the hydrolysis reaction and bring the acid value of the acetone soluble part of the thermoplastic resin composition to be within the predetermined range of the present invention, 0.1 to 5% by weight is preferable, particularly 0.15 to 2%. % By weight is preferred.
[0066]
The method for adjusting the moisture content in the graft copolymer (B) to within a predetermined range is not particularly limited, but for example, by controlling the dehydration time, drying temperature, air flow, etc. of the graft copolymer (B), the desired amount can be obtained. It is possible to adjust the moisture content value. In addition, for example, it is also possible to adjust the moisture content by separately adding water to the graft copolymer (B).
[0067]
The graft copolymer (B) can also be produced by a bulk polymerization method. When the bulk polymerization method is used, it is possible to directly add the graft copolymer (B) from the demonomer machine in the molten state directly to the vinyl copolymer (A). Although it is possible to add the released graft copolymer (B) to the vinyl copolymer (A), it is usually in a molten state from the demonomer machine in terms of preventing thermal deterioration and continuation of the process. It is more preferable to add the graft copolymer (B) directly.
[0068]
The mixing method of the vinyl copolymer (A) and the graft copolymer (B) is not particularly limited, but in terms of color tone, impact resistance, etc., the molten state during the continuous bulk polymerization process or during the continuous solution polymerization process The method of melt-mixing the graft copolymer (B) after adding the graft copolymer (B) to the vinyl copolymer (A) is preferably selected. Further, at that time, it is preferable to add 90 to 5 parts by weight of the graft copolymer (B) to 10 to 95 parts by weight of the vinyl copolymer (A) in a molten state, and more preferably a vinyl copolymer ( A) After adding 70-5 weight part of graft copolymers (B) to 30-95 weight part, it melt-mixes. The graft copolymer (B) is preferably added continuously. The addition of the graft copolymer (B) at this time is such that the residual monomer amount is 10% by weight or less during or after the demonomer step of the continuous bulk polymerization process of the vinyl copolymer (A), More preferably, it is particularly preferably performed when the amount is 5% by weight or less in order to suppress deterioration due to the thermal history of the rubber component during the subsequent demonomer operation, and to further improve the color tone and impact resistance.
[0069]
Further, during the step of melt-kneading after mixing the vinyl copolymer (A) and the graft copolymer (B), water is added in an amount of 0.1 to 5% by weight based on the thermoplastic resin composition. It is particularly preferable to add it in order to more easily control the hydrolysis reaction of the unsaturated carboxylic acid ester monomer (a2) in the process.
[0070]
Mixing after adding the graft copolymer (B) to the vinyl copolymer (A) is preferably melt-mixed in order to sufficiently exhibit physical properties such as impact resistance. This melt mixing may be performed at the time of addition mixing or may be performed after the mixture is isolated, for example, at the time of melt molding.
[0071]
There is no restriction | limiting in particular in the addition method of a graft copolymer (B), It is possible to add by arbitrary methods. Usually, various feeders such as a belt type feeder, a screw type feeder, a single screw extruder, a twin screw extruder and the like are continuously added. A single-screw extruder and a twin-screw extruder whose discharge ends are connected to the part are particularly preferably used. These continuous addition apparatuses preferably have a resin quantitative supply structure. Moreover, it is preferable for the continuous addition apparatus to have a heating apparatus and to add the graft copolymer (B) in a semi-molten or molten state in order to improve the mixed state. For this purpose, an extruder or the like having a heating device can be used.
[0072]
The ratio of the triple sequence of acrylonitrile monomer units present in the acetone-soluble component of the thermoplastic resin composition in the present invention is 10% by weight or less based on the acetone-soluble component. The triple sequence of acrylonitrile monomer units is a segment in the copolymer contained in the acetone-soluble component represented by the following (formula 2), and the copolymer having such a segment has a high temperature. In the state exposed to, the intramolecular cyclization reaction shown in the following (Formula 3) proceeds, which causes coloring.
[Chemical 1]

[0073]
When the ratio of the triple sequence of acrylonitrile monomer units exceeds 10% by weight with respect to the acetone-soluble content, the color stability at the time of melting of the resulting thermoplastic resin composition becomes poor. The proportion of the triple sequence is preferably less than 8% by weight, more preferably 5% by weight or less from the viewpoint of color tone stability. The thermoplastic resin composition in which the proportion of the triple sequence of acrylonitrile monomer units in the acetone-soluble component is controlled to 10% by weight or less is, for example, the triple sequence of acrylonitrile monomer units as described above. This is achieved by using the vinyl copolymer (A) in which the ratio of is controlled to 10% by weight or less.
[0074]
The thermoplastic resin composition of the present invention includes polyolefins such as vinyl chloride, polyethylene, and polypropylene, polyamides such as nylon 6 and nylon 66, polyethylene terephthalate, polybutylene terephthalate, and polycyclohexanedimethyl terephthalate as long as the object of the present invention is not impaired. The performance as a molding resin can be improved by adding polyester, polycarbonate, and various elastomers. In addition, as necessary, antioxidants such as hindered phenols, sulfur-containing organic compounds, and phosphorus-containing organic compounds, thermal stabilizers such as phenols and acrylates, benzotriazoles, benzophenones, salicylates, etc. Various stabilizers such as ultraviolet absorbers, organic nickel-based and hindered amine-based light stabilizers, higher fatty acid metal salts, higher fatty acid amides and other lubricants, phthalates, phosphates and other plasticizers, poly Flame retardants / flame retardants such as bromodiphenyl ether, tetrabromobisphenol-A, brominated epoxy oligomers, brominated polycarbonate oligomers, etc., phosphorus compounds, antimony trioxide, antistatic agents, carbon black, oxidation Titanium, pigments and dyes can also be addedFurthermore, reinforcing agents and fillers such as glass fibers, glass flakes, glass beads, carbon fibers, and metal fibers can be added.
[0075]
There is no restriction | limiting in particular about the addition method of these additives, It is also possible to add continuously with a graft copolymer (B), and also vinyl-type copolymer (A), graft copolymer (B), and It is possible to use various methods such as adding a mixed pellet as a post-process after preparing the mixed pellet.
[0076]
Thus, the thermoplastic resin composition of the present invention is excellent in balance of transparency, chemical resistance and color tone stability, and also in mechanical strength balance such as impact resistance and rigidity, molding processability and cost performance. Since it is excellent, it can be widely used in application fields such as home appliances, communication-related equipment, and general goods.
[0077]
【Example】
In order to describe the present invention more specifically, examples and comparative examples are given below, but these examples do not limit the present invention. Unless otherwise specified, “%” indicates wt% and “parts” indicates parts by weight. A method for analyzing the resin characteristics of the thermoplastic resin composition will be described below.
(1) Weight average rubber particle diameter of rubber polymer
Utilizing the sodium alginate method described in `` Rubber Age Vol. 88 p.484-490 (1960), by E. Schmidt, PHBiddison '', that is, the polybutadiene particle size to be creamed differs depending on the concentration of sodium alginate, According to a method for obtaining a particle size of a cumulative weight fraction of 50% from the creamed weight ratio and the cumulative weight fraction of sodium alginate concentration.
(2) Graft ratio of graft copolymer (B)
100 ml of acetone was added to a predetermined amount (m; about 1 g) of the graft copolymer (B) which had been vacuum-dried at 80 ° C. for 4 hours, and refluxed in a 70 ° C. water bath for 3 hours. After centrifuging at (10000 G) for 40 minutes, the insoluble matter was filtered, this insoluble matter was vacuum dried at 80 ° C. for 4 hours, and the weight (n) was measured. The graft ratio was calculated from the following formula. Here, L is the rubber content of the graft copolymer.
Graft rate (%) = {[(n) − (m) × L] / [(m) × L]} × 100
[0078]
(3) Emulsifier content of graft copolymer (B)
About 20 g of the graft copolymer (B) vacuum-dried at 80 ° C. for 4 hours was precisely weighed, 10 times the amount of 10% sulfuric acid was added, and the mixture was boiled for 30 minutes in a 500 ml beaker. This was filtered off with a 100-mesh wire mesh, the residual solid was taken, washed in 200 ml of ion-exchanged water for 1 minute, and filtered twice. Furthermore, this solid content was divided into two, placed in a round bottom flask, 100 ml of methanol was added to each, and the mixture was refluxed in a hot water bath set at 70 ° C. for 3 hours. Further, this solution and the solid content were centrifuged at 8800 rpm (10000 G) for 40 minutes, and the filtrate obtained by filtering the supernatant was evaporated to dryness, and further dried under vacuum at 80 ° C. for 4 hours to obtain a solid content. It was. This solid content was precisely weighed as an emulsifier contained in the graft copolymer (B), and the emulsifier content was calculated.
(4) Moisture content of graft copolymer (B)
The measurement sample was precisely weighed and measured using a Karl Fischer moisture meter.
(5) Reduced viscosity ηsp / c of vinyl copolymer (A)
The measurement sample was dissolved in methyl ethyl ketone, and the reduced viscosity ηsp / c was measured at 30 ° C. using a Ubbelohde viscometer as a 0.4 g / 100 ml methyl ethyl ketone solution.
(6) Reduced viscosity ηsp / c of graft component (d)
200 g of acetone was added to 1 g of the graft copolymer (B) which had been vacuum-dried at 80 ° C. for 4 hours, and refluxed in a 70 ° C. water bath for 3 hours. The solution was centrifuged at 8800 rpm (10000 G) for 40 minutes. After separation, the insoluble matter is filtered. The filtrate was concentrated on a rotary evaporator, and the precipitate was vacuum-dried at 80 ° C. for 4 hours, and the same method as in (5) above was used to obtain a 0.4 g / 100 ml methyl ethyl ketone solution at 30 ° C. using an Ubbelohde viscometer. The reduced viscosity ηsp / c was measured.
[0079]
(7) Monomer composition of acetone-soluble matter
100 ml of acetone is added to 1 g of a resin composition sample, and the mixture is refluxed in a hot water bath at 70 ° C. for 3 hours. The solution is centrifuged at 8800 rpm (10000 G) for 40 minutes, and insoluble matter is filtered. The filtrate was concentrated with a rotary evaporator, and a film with a thickness of 30 ± 5 μm was prepared using a hot press set at 220 ° C. using a precipitate dried in vacuo at 80 ° C. for 4 hours (acetone soluble component). The monomer composition was determined from the area of each peak appearing on the chart obtained by analyzing this film as a sample by FT-IR. The correspondence between each monomer and peak is as follows.
Methyl methacrylate monomer unit: peak of 3460 cm −1 which is a harmonic overtone peak of 1730 cm −1 attributed to C═O stretching vibration of carbonyl group of ester,
Methacrylic acid monomer unit: peak at 1690 cm −1 attributed to C═O stretching vibration of carbonyl group of carboxylic acid,
Styrene monomer unit: peak at 1605 cm −1 attributed to vibration of the benzene nucleus,
Acrylonitrile monomer unit:-2240 cm-1 peak attributed to -C≡N stretching,
(8) φST / φMMA distribution of acetone soluble matter
80 ml of methyl ethyl ketone was added to 2 g of the acetone-soluble sample obtained in the same manner as in the above (7), and the mixture was allowed to stand at room temperature for 24 hours for dissolution. The weight of the system copolymer was measured, and the monomer composition was determined by FT-IR in the same manner as in the above (7) using the precipitate as a sample. And the cumulative weight fraction of the precipitate with respect to the acetone-soluble component used as a sample, the aromatic vinyl monomer (a1) content and the unsaturated carboxylic acid alkyl ester monomer (a2) content The weight ratio (φST / φMMA) was plotted, and the proportion (% by weight) of the acetone soluble component contained in the range of 0.75 to 1.2 times the average value of the whole acetone soluble component.
[0080]
(9) Acid value of acetone soluble matter
100 ml of acetone is added to 10 g of a resin composition sample and refluxed in a hot water bath at 70 ° C. for 3 hours. The solution is centrifuged at 8800 rpm (10000 G) for 40 minutes, and the insoluble matter is filtered. The filtrate was gently poured into 2 L of methanol at room temperature while stirring to reprecipitate, and the supernatant was discarded to obtain a precipitate. This was further dissolved in 200 ml acetone and reprecipitated again with 2 L methanol, and the resulting precipitate was vacuum-dried at 80 ° C. for 4 hours to obtain a solid (acetone soluble component). About 10 g of acetone-soluble matter obtained by performing several samples of this operation was precisely weighed and placed in a 100 ml Erlenmeyer flask with a stopper, and 40 ml of acetone was added thereto and stirred for 2 hours to dissolve uniformly. Three drops of phenolphthalein solution was added to this solution, and neutralization titration was performed with 1/10 N KOH. Using this titration amount, the acid value was calculated according to the following formula. Moreover, the neutralization titration was performed also about acetone stirred for 2 hours like the measurement sample, and this was used as the blank and the titer was correct | amended.
[Expression 1]

However, the values in the formula are as follows.
X: Titration volume (ml), X0: Blank titration volume (ml), W: Sample volume (g)
[0081]
(8) Triple sequence ratio of acrylonitrile monomer units in acetone soluble matter
Using acetone-soluble matter obtained by the same operation as the above (7) as a sample,¹³Utilizing the fact that the α-carbon signal shift of the acrylonitrile monomer unit appearing in C-NMR is slightly different depending on the type of adjacent monomer, the proportion of the triple sequence is quantified from the signal integral value, and the total monomer unit Among them, it was expressed as the weight fraction of the acrylonitrile monomer unit at the center of the triple sequence. The measurement conditions are as follows.
[0082]
Apparatus: JEOL JNM-GSX400 type
Observation frequency: 100.5 MHz
Solvent: DMSO-d₆
Concentration: 445 mg / 2.5 mL
Chemical shift criteria: Me_FourSi
Temperature: 110 ° C
Observation width: 20000Hz
Data point: 32K
flip angle: 90 ° (21μs)
pulsedelaytime: 5.0 s
Integration count: 7400 or 8400
Decoupling: gated decoupling (without NOE)
Acrylonitrile sequence attribution (A: Acrylonitrile, S: Styrene)
: -A-A-A- 118.6-119.2 ppm
-A-A-S- 119.3-120.2 ppm
-S-A-S- 120.2 to 121.3 ppm
[0083]
(9) Triple sequence ratio of acrylonitrile monomer units in vinyl copolymer (A)
It calculated | required by the same operation as said (8) except using a vinyl-type copolymer (A) as a sample instead of the said acetone soluble part.
(10) Refractive index of vinyl copolymer (A), graft component (d) or acetone soluble matter
A small amount of 1-bromonaphthalene was dropped on the measurement sample, and the refractive index was measured under the following conditions using an Abbe refractometer.
Light source: Sodium lamp D line, Measurement temperature: 20 ° C
As a sample of the graft component (d), a vacuum dried product of the precipitate obtained in the same manner as in the above (6) was used.
Moreover, as a measurement sample of an acetone soluble part, the acetone soluble part obtained similarly to said (7) was used.
[0084]
(11) Refractive index of rubbery polymer (b)
From the literature, the following values were used: The copolymer rubber is identified by FT-IR, viscoelasticity measurement, and the like, and the refractive index (nD) of the copolymer rubber can be obtained from each copolymer component by the following formula.
Polybutadiene refractive index: 1.516
nD = 1.516 ・ MB + 1.594 ・ MS + 1.516 ・ MA
However, the values in the formula are as follows.
nD: Refractive index of copolymer rubber, MB: butadiene content (wt%), MS: styrene content (wt%), MA: acrylonitrile content (wt%)
[0085]
(12) Color tone of resin composition (YI value)
The measurement was performed according to JIS K7103.
(13) Transparency of resin composition (total light transmittance, haze value)
The pellet of the resin composition dried for 3 hours in a hot air dryer at 80 ° C. was filled into a IS50A molding machine manufactured by Toshiba Corporation set at a cylinder temperature of 250 ° C., and immediately formed into a square plate molded product (thickness 3 mm). The haze value [%] was measured using a direct reading haze meter manufactured by Toyo Seiki Co., Ltd.
(14) Izod impact strength of resin composition
Measured by ASTM D256 (23 ° C., with V notch).
(15) Tensile strength of resin composition
Measured according to ASTM 638.
[0086]
(16) Chemical resistance
After the press-molded test piece (127 × 12.7 × 1.5 mm) 12 is fixed along the ¼ ellipse jig 11 as shown in FIG. 2, the drug (ethanol, isopropanol, or liquid) Detergent “Top”) is applied to the entire surface of the molded article, and a paper wiper (“Kimwipe” manufactured by Crecia Co., Ltd.) is laid on top of the molded article. In order to suppress the evaporation of the medicine, the molded product is put together with the 1/4 oval jig 11 in a plastic bag and sealed. After standing for 24 hours in a 23 ° C. environment, the presence or absence of cracks and cracks was confirmed, the length in the long axis direction (Xmm) of the crack occurrence point was measured, and the critical strain (ε% ), The value is less than 0.5% ×, 0.5% to 1.0% Δ, 1.0% to 2.0% ○, 2.0% Those exceeding 5,000 were evaluated as ◎.
[Expression 2]

However, the symbols in Equation 4 and FIG. 2 are as follows.
ε: Critical strain (%)
a: Long axis of jig (mm) [127 mm]
b: Jig short axis (mm) [38mm]
t: Thickness of test piece (mm) [1.5 mm]
X: Long axis length of the crack occurrence point (mm)
[0087]
(Reference example) Graft copolymer
B-1: Polybutadiene latex (rubber particle diameter 0.3 μm, gel content 85%) 50 parts (solid content conversion), pure water 180 parts, sodium formaldehyde sulfoxylate 0.4 part, ethylenediaminetetraacetate sodium 0.1 Part, 0.01 part of ferrous sulfate and 0.1 part of sodium phosphate were charged into a reaction vessel, and after nitrogen substitution, the temperature was adjusted to 65 ° C., with stirring, 11.5 parts of styrene, 4.0 parts of acrylonitrile, methacrylic acid A mixture of 34.5 parts of methyl acid and 0.3 part of n-dodecyl mercaptan was continuously added dropwise over 4 hours. At the same time, 0.25 parts of cumene hydroperoxide, 2.5 parts of sodium oleate as an emulsifier and 25 parts of pure water were continuously added dropwise over 5 hours, and after completion of the addition, the mixture was further maintained for 1 hour for polymerization. Ended.
[0088]
The latex product obtained after completion of polymerization was coagulated by pouring into 2000 parts of 95 ° C. water to which 1.0 part of sulfuric acid was added, and then neutralized with 0.8 part of sodium hydroxide. Thus, a coagulated slurry was obtained. This was centrifuged, washed in 2000 parts of water at 40 ° C. for 5 minutes, centrifuged, and dried in a hot air dryer at 60 ° C. for 12 hours to prepare a powdery graft copolymer. Table 1 shows the graft characteristics of the obtained graft copolymer (B-1), the refractive index of the graft component, the emulsifier content, and the moisture content.
[0089]
B-2: Polymerization / coagulation / neutralization / washing / drying / separation in the same manner as in B-1 except that a vinyl monomer mixture and polybutadiene latex having the composition shown in Table 1 were used. The illustrated graft copolymer (B-2) was prepared. The graft characteristics, graft component refractive index, emulsifier content and moisture content of the obtained graft copolymer were as shown in Table 1.
[0090]
B-3: After centrifuging the coagulated slurry after polymerization, coagulation and neutralization in the same manner as in B-1, washing and centrifuging for 10 minutes in 2000 parts of water at 60 ° C. is repeated three times. Then, drying was carried out in a hot air dryer at 60 ° C. for 48 hours to prepare a powdery graft copolymer (B-3). The graft characteristics, graft component refractive index, emulsifier content and moisture content of the obtained graft copolymer were as shown in Table 1.
[0091]
[Example 1]
2m with condenser for evaporation of monomer vapor and helical ribbon blade^ThreeComplete mixing type polymerization tank, single-screw extruder type preheater, twin-screw extruder type demonomer machine and two-shaft having a heating device connected in tandem from the tip of the demonomer machine to the 1/3 length barrel part Polymerization and resin mixing were carried out using a continuous bulk polymerization apparatus consisting of an extruder type feeder.
[0092]
First, a monomer mixture comprising 17.5 parts of styrene, 30.0 parts of acrylonitrile, 52.5 parts of methyl methacrylate, 0.15 part of n-octyl mercaptan and 0.01 part of di-t-butyl peroxide, The polymer was continuously supplied to the polymerization tank at 150 kg / hour, and continuous bulk polymerization was performed while maintaining the polymerization temperature at 130 ° C. and the internal pressure of 0.08 MPa. The polymerization rate of the polymerization reaction mixture at the exit from the polymerization vessel was controlled between 74 and 76%.
[0093]
After the polymerization reaction mixture is preheated by a single screw extruder type preheater, unreacted monomer is evaporated and recovered from the vent port under reduced pressure by a twin screw extruder type demonomer, and the recovered unreacted monomer is continuously The mixture was refluxed to the polymerization tank. A styrene / acrylonitrile / methyl methacrylate copolymer with an apparent polymerization rate increased to 99% or more at 1/3 from the outlet end of the demonomer machine, and a phenol-based stabilizer by a twin screw extruder type feeder. Some t-butylhydroxytoluene 0.225 kg / hr, tri (nonylphenyl) phosphite 0.225 kg / hr which is a phosphorus stabilizer, and half of the graft copolymer (B-1) produced in the Reference Example A molten product of 60 kg / hour was supplied, and melt-kneaded with a styrene / acrylonitrile / methyl methacrylate copolymer in a demonomer machine. During the melt-kneading process, water was supplied at a rate of 1 kg from the outlet end of the demonomer machine at 2 kg / hour. This water and other volatile components were further removed by evaporation under reduced pressure from a vent port installed downstream of the demonomer. Thereafter, the molten polymer was discharged in a strand shape, and a resin composition pellet was obtained by a cutter. The resin characteristic evaluation results are shown in Table 3.
[0094]
[Example 2]
The composition of the monomer mixture is 17.5 parts of styrene, 30.0 parts of acrylonitrile, 52.5 parts of methyl methacrylate, 0.15 part of n-octyl mercaptan and 0.01 part of di-t-butyl peroxide, and heated. The resin composition pellets were obtained in the same manner as in Example 1 except that the graft copolymer (B-2) produced in the reference example was supplied in the semi-molten state at the rate shown in Table 2 from the biaxial extruder type feeder. Obtained. The resin characteristic evaluation results are shown in Table 3.
[0095]
[Example 3]
The composition of the monomer mixture is 20.0 parts of styrene, 20.0 parts of acrylonitrile, 60.0 parts of methyl methacrylate, 0.15 parts of n-octyl mercaptan and 0.01 parts of di-t-butyl peroxide and heated. The resin composition pellets were obtained in the same manner as in Example 1 except that the graft copolymer (B-1) produced in the reference example was supplied in the semi-molten state at the rate shown in Table 2 from the biaxial extruder type feeder. Obtained. The resin characteristic evaluation results are shown in Table 3.
[0096]
[Example 4]
2m with condenser for evaporation of monomer vapor and helical ribbon blade^ThreePolymerization was carried out using a continuous bulk polymerization apparatus consisting of a complete mixing type polymerization tank, a single-screw extruder type preheater, and a twin-screw extruder type demonomer.
[0097]
First, a monomer mixture comprising 20.0 parts of styrene, 20.0 parts of acrylonitrile, 60.0 parts of methyl methacrylate, 0.15 part of n-octyl mercaptan and 0.01 part of di-t-butyl peroxide, The polymer was continuously supplied to the polymerization tank at 150 kg / hour, and continuous bulk polymerization was performed while maintaining the polymerization temperature at 130 ° C. and the internal pressure of 0.08 MPa. The polymerization rate of the polymerization reaction mixture at the exit from the polymerization vessel was controlled between 74 and 76%.
[0098]
After the polymerization reaction mixture is preheated by a single screw extruder type preheater, unreacted monomer is evaporated and recovered from the vent port under reduced pressure by a twin screw extruder type demonomer, and the recovered unreacted monomer is continuously The mixture was refluxed to the polymerization tank. Thereafter, the molten polymer was discharged in a strand shape, and vinyl copolymer (A) pellets were obtained with a cutter.
[0099]
The obtained pellet-shaped vinyl copolymer (A) and the graft copolymer (B-1) produced in the reference example are blended in the proportions shown in Table 2, and t-butylhydroxytoluene which is a phenol-based stabilizer. After adding 0.1 part and 0.1 part of tri (nonylphenyl) phosphite which is a phosphorus-based stabilizer and dry blending, a water injection facility is provided at 1/3 from the outlet end, and 1 / Using a 40 mmφ extruder with a vent at No. 6, melt-kneaded at 230 ° C. while pouring water at a ratio of 1% by weight with respect to the resin composition, and extrusion pelletized to obtain resin composition pellets. . The resin characteristic evaluation results are shown in Table 3.
[0100]
[Example 5]
The graft copolymer (B-3) produced in the reference example was supplied from the heated twin-screw extruder type feeder at a rate shown in Table 2 in a semi-molten state, and water supply to the demonomer was not performed. Except that, resin composition pellets were obtained in the same manner as in Example 1.
The resin characteristic evaluation results are shown in Table 3.
[0101]
[Comparative Example 1]
The composition of the monomer mixture was 24.0 parts of styrene, 5.0 parts of acrylonitrile, 71.0 parts of methyl methacrylate, 0.15 parts of n-octyl mercaptan and 0.01 parts of di-t-butyl peroxide and heated. The resin composition pellets were obtained in the same manner as in Example 1 except that the graft copolymer (B-1) produced in the reference example was supplied in the semi-molten state at the rate shown in Table 2 from the biaxial extruder type feeder. Obtained. The resin characteristic evaluation results are shown in Table 3.
[0102]
[Comparative Example 2]
The composition of the monomer mixture is 10.0 parts of styrene, 60.0 parts of acrylonitrile, 30.0 parts of methyl methacrylate, 0.15 parts of n-octyl mercaptan and 0.01 parts of di-t-butyl peroxide and heated. The resin composition pellets were obtained in the same manner as in Example 1 except that the graft copolymer (B-1) produced in the reference example was supplied in the semi-molten state at the rate shown in Table 2 from the biaxial extruder type feeder. Obtained. The resin characteristic evaluation results are shown in Table 3.
[0103]
[Table 1]

[0104]
[Table 2]

[0105]
[Table 3]

As in Examples 1 to 5, it can be seen that the thermoplastic resin composition specified in the present invention is excellent in balance in all of transparency, tone stability and chemical resistance. In particular, in Examples 1 to 3, the mixing method of the vinyl copolymer (A) and the graft copolymer (B) and the acid value in the acetone-soluble component are in the above-mentioned preferable range, so that the transparency is particularly high. The color properties, impact resistance, and rigidity were excellent in balance of physical properties and excellent.
[0106]
However, in the resin compositions obtained in Comparative Examples 1 and 2, the monomer composition constituting the vinyl copolymer (A) and the acrylonitrile triple sequence ratio in the acetone-soluble component are outside the scope of the present invention. Therefore, any one of transparency, color tone stability and chemical resistance was inferior.
[0107]
【The invention's effect】
The thermoplastic resin composition of the present invention is excellent in balance of transparency, chemical resistance and color stability, and excellent in mechanical strength balance such as impact resistance and rigidity, molding processability and cost performance, Utilizing these characteristics, it can be widely used in application fields such as home appliances, communication-related equipment, and general merchandise.
[Brief description of the drawings]
FIG. 1 is an apparatus longitudinal cross-sectional schematic view showing one embodiment of an apparatus for producing a resin composition of the present invention by a method of continuous bulk polymerization and resin mixing.
FIG. 2 is a longitudinal sectional view for explaining a 1/4 elliptical jig used for evaluation of chemical resistance and a method of using the same.
[Explanation of symbols]
1: Reaction tank
2: Preheater
3: Twin screw extruder type demonomer machine
4: Melt kneading zone
5: Twin screw extruder type feeder
11: 1/4 oval jig
12: Test piece
13: Chemical application surface
14: Crack
X: Distance from the crack occurrence point

Claims (9)

Aromatic vinyl monomer (a1) 5 to 40% by weight, unsaturated carboxylic acid alkyl ester monomer (a2) 30 to 80% by weight, vinyl cyanide monomer (a3) 10 to 50% by weight And a vinyl copolymer (A) obtained by continuous bulk polymerization or continuous solution polymerization of a vinyl monomer mixture (a) containing 0 to 40% by weight of another monomer (a4) copolymerizable therewith (A4) A thermoplastic resin composition in which a graft copolymer (B) obtained by graft polymerization of one or more vinyl monomers (c) in the presence of a rubbery polymer (b) is dispersed. The vinyl copolymer (A) has a solubility parameter of 10.5 to 12.5 (cal / ml) ^1/2 , and the acrylonitrile monomer present in the acetone-soluble component of the thermoplastic resin composition The proportion of the triple sequence of body units is soluble in acetone. A transparent thermoplastic resin composition, characterized in that the content is 10% by weight or less based on the content. The transparent thermoplastic resin composition according to claim 1, having a haze value of 30% or less. 3. The transparent according to claim 1, wherein the difference in refractive index between the rubbery polymer component constituting the graft copolymer (B) and the acetone-soluble component is within 0.03. 4. sex thermoplastic resin composition. The transparent thermoplastic resin composition according to any one of claims 1 to 3 , wherein an acid value of the acetone-soluble component is 0.01 to 1 mgKOH / g. The vinyl monomer mixture (a) and the vinyl monomer mixture (c) are aromatic vinyl monomers (a1) 5 to 40% by weight, unsaturated carboxylic acid alkyl ester monomers (a2). 30 to 80% by weight, vinyl cyanide monomer (a3) 10 to 50% by weight and other monomers copolymerizable with these (a4) 0 to 40% by weight, and unsaturated carboxylic acid It is a monomer mixture which does not contain a system monomer (however, except an unsaturated carboxylic acid alkylester monomer (a2)) (a5), It is any one of Claims 1-4 A transparent thermoplastic resin composition. The vinyl-based copolymer (A) is produced by continuous bulk polymerization or continuous solution polymerization of the vinyl-based monomer mixture (a), and then grafted to the molten vinyl-based copolymer (A). The transparent thermoplastic resin composition according to any one of claims 1 to 5 , which is a rubber-reinforced styrene-based resin composition that is continuously produced by a method of adding the blend (B) and melt mixing. In the middle of the demonomer process or after the demonomer process in the process of producing the vinyl copolymer (A) by performing demonomer subsequent to the polymerization of the vinyl monomer mixture (a), the molten vinyl system The transparent thermoplastic resin composition of Claim 6 manufactured by adding a graft copolymer (B) to a copolymer (A). The transparent heat according to any one of claims 1 to 7 , which is produced by bringing the graft copolymer (B) when added to the vinyl copolymer (A) into a semi-molten or molten state. Plastic resin composition. The vinyl-based copolymer (A) is produced by continuous bulk polymerization or continuous solution polymerization of the vinyl-based monomer mixture (a), and then grafted to the molten vinyl-based copolymer (A). A method for producing a transparent thermoplastic resin composition, wherein the thermoplastic resin composition according to any one of claims 1 to 6 is produced by adding the coalesced (B) and melt mixing.

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