JP3685848B2 - Polyacetal resin composition and method for producing the same - Google Patents

Description

（式中、Ｒ¹ は水素原子又はメチル基、Ｒ² 〜Ｒ⁵ は同一又は異なって水素原子、ハロゲン原子、アルキル基、アルコキシ基、アルコキシカルボニル基、アシル基、アシルオキシ基を示す。ｎは０又は１である）
前記ハロゲン原子には、フッ素、塩素、臭素、ヨウ素原子が含まれ、アルキル基には、例えば、メチル、エチル、プロピル、イソプロピル、ブチル、イソブチル、ｓｅｃ−ブチル、ｔ−ブチル、ペンチル、ヘキシル、オクチル基など炭素数１〜１０程度のアルキル基が含まれる。好ましいアルキル基には炭素数１〜６程度、特に炭素数１〜４程度の低級アルキル基が含まれる。
アルコキシ基には、例えば、メトキシ、エトキシ、プロポキシ、ブトキシ、ｔ−ブトキシ、ペンチルオキシ、ヘキシルオキシ基などの炭素数１〜６程度の低級アルコキシ基が含まれる。
アルコキシカルボニル基としては、例えば、メトキシカルボニル、エトキシカルボニル、プロポキシカルボニル、ブトキシカルボニル、ｔ−ブトキシカルボニル、ペンチルオキシカルボニル、ヘキシルオキシカルボニル基などのアルコキシ部分の炭素数が１〜６程度の低級アルコキシカルボニル基である場合が多い。
アシル基には、ホルミル、アセチル、プロピオニル、ブチリル、バレリル、ピバロイル基などの炭素数１〜６程度の低級アシル基が含まれる。アシルオキシ基としては、例えば、アセチルオキシ、プロピオニルオキシ、ブチリルオキシ、バレリルオキシ、ピバロイルオキシ基などが例示できる。
Ｒ² 〜Ｒ⁵ は同一又は異なって水素原子、ハロゲン原子、低級アルキル基である場合が多い。特にＲ² 〜Ｒ⁵ は同一又は異なって水素原子又は低級アルキル基である場合が多い。
【００４５】
ｎが０の化合物には、前記グリシジル（メタ）アクリレートが含まれる。ｎが１の化合物の具体例としては、例えば、Ｎ−［４−（２，３−エポキシプロポキシ）フェニルメチル］アクリルアミド、Ｎ−［４−（２，３−エポキシプロポキシ）−３，５−ジメチルベンジル］アクリルアミド、Ｎ−［４−（２，３−エポキシプロポキシ）−３，５−ジエチルベンジル］アクリルアミド、Ｎ−［４−（２，３−エポキシプロポキシ）−３，５−ジブチルベンジル］アクリルアミドなどのＮ−［４−（２，３−エポキシプロポキシ）−３，５−ジアルキルベンジル］アクリルアミド、Ｎ−［４−（２，３−エポキシプロポキシ）−２，６−ジメチルベンジル］アクリルアミド、Ｎ−［４−（２，３−エポキシプロポキシ）−２，５−ジメチルベンジル］アクリルアミド、Ｎ−［４−（２，３−エポキシプロポキシ）−２，３，５，６−テトラメチルベンジル］アクリルアミドなどが例示される。
【００４６】
重合性化合物は、室温、大気圧下で液状又は固体状（非ガス状）である場合が多い。これらの重合性化合物のうち、常圧における沸点７０℃以上、好ましくは１００℃以上、さらに好ましくは１２０℃以上の化合物を用いる場合が多く、好ましい重合性化合物の沸点は、無水マレイン酸、（メタ）アクリル酸、グリシジル（メタ）アクリレート、前記式（１）で表される化合物（例えば、Ｎ−［４−（２，３−エポキシプロポキシ）−３，５−ジメチルベンジル］アクリルアミド）などのように、常圧で１４０℃以上である場合が多い。
【００４７】
なお、変性効率、変性ポリアセタールおよび成形品の利用効率を高めるため、変性ポリアセタールは、充填剤や補強剤の非共存下、前記重合性化合物により変性されたポリアセタールであるのが好ましい。充填剤や補強剤の非共存下で変性された変性ポリアセタールを用いると、用途に応じて複数の熱可塑性樹脂と混合するだけで、樹脂組成物を調製でき、アロイ化や複合化の自由度が大きくなる。
【００４８】
前記官能基の導入量は、熱可塑性樹脂や添加剤との親和性を向上できる範囲で選択でき、例えば、（Ａ）ポリアセタールに対して重合性化合物換算で、０．１〜３０重量％（例えば０．１〜２０重量％程度）、好ましくは０．２〜２５重量％（例えば０．２〜１５重量％程度）、さらに好ましくは０．３〜２０重量％（例えば０．３〜１０重量％程度）であり、０．２〜１０重量％程度である場合が多い。
【００４９】
前記変性ポリアセタールは、（Ａ）ポリアセタールと、（Ｂ）官能基を有する重合性化合物とを加熱し、前記重合性化合物の残基をポリアセタールに導入することにより製造できる。（Ａ）ポリアセタールと（Ｂ）官能基を有する重合性化合物とは、（Ｃ）ラジカル発生剤（重合開始剤）の非存在下で加熱してもよいが、（Ｃ）ラジカル発生剤の存在下で加熱すると、重合性化合物の残基を効率よく導入できる。
【００５０】
（Ｃ）ラジカル発生剤は、フリーラジカルを発生し、重合性化合物の重合を開始する重合開始剤としての機能を有する化合物であれば、その種類は特に制限されない。ラジカル発生剤としては、有機過酸化物などの過酸化物、アゾ化合物、その他のラジカル重合開始剤が使用できる。
【００５１】
過酸化物としては、例えば、ｔ−ブチルヒドロペルオキシド、ｐ−メンタンヒドロペルオキシド、クメンヒドロペルオキシド、ジイソプロピルベンゼンヒドロペルオキシド、２，５−ジメチルヘキサン−２，５−ジヒドロペルオキシドなどのアルキルヒドロペルオキシド；ジ−ｔ−ブチルパーオキシド、ｔ−ブチルクミルパーオキシド、ジクミルパーオキシド、ｔ−ブチルパーオキシクメン、２，５−ジメチル−２，５−ジ（ｔ−ブチルパーオキシ）ヘキサン、２，５−ジメチル−２，５−ジ（ｔ−ブチルパーオキシ）ヘキシン−３、α，α′−ビス（ｔ−ブチルパーオキシ−ｍ−イソプロピル）ベンゼンなどの過酸化ジアルキル；ベンゾイルパーオキシド、ラウロイルパーオキシド、ｐ−クロロベンゾイルパーオキシドなどの過酸化ジアシル；メチルエチルケトンパーオキシド、１，１−ビス（ｔ−ブチルパーオキシ）−３，３，５−トリメチルシクロヘキサン、１，１−ビス（ｔ−ブチルパーオキシ）シクロドデカンなどのアルキリデンペルオキシド；ｎ−ブチル−４，４−ビス（ｔ−ブチルパーオキシ）バレレート、ｔ−ブチルパーオキシベンゾエートなどの過酸化エステルなどが挙げられる。
【００５２】
アゾ化合物としては、例えば、１−［（１−シアノ−１−メチルエチル）アゾ］ホルムアミド、２，２′−アゾビス｛２−メチル−Ｎ−［１，１−ビス（ヒドロキシメチル）エチル］プロピオンアミド｝などのアゾアミド系化合物；１，１−アゾビス（シクロヘキサン−１−カルボニトリル）、２−フェニルアゾ−４−メトキシ−２，４−ジメチルバレロニトリル、２，２′−アゾビス［２−（ヒドロキシメチル）プロピオニトリル］、アゾビスイソブチロニトリルなどのアゾニトリル系化合物；２，２′−アゾビス（２，４，４−トリメチルペンタン）などのアルキルアゾ系化合物が挙げられる。
【００５３】
他のラジカル発生剤としては、例えば、過硫酸カリウム、過硫酸ナトリウム、過硫酸アンモニウムなどの過硫酸塩も使用できる。
これらのラジカル発生剤は単独で使用してもよく、同種又は異種のものを組合せて使用してもよい。
【００５４】
重合性化合物（Ｂ）の官能基をポリアセタール（Ａ）に効率よく導入するため、好ましいラジカル発生剤には、半減期１分に対応する温度が１３０℃以上、好ましくは１５０℃以上、さらに好ましくは１６０℃以上の化合物が含まれる。このようなラジカル発生剤は、アルキルヒドロペルオキシド、過酸化ジアルキル、過酸化エステル、アゾ化合物である場合が多い。
【００５５】
（Ｂ）官能基を有する重合性化合物の割合は、所望する改質度および変性ポリアセタールの用途などに応じて選択でき、例えば、（Ａ）ポリアセタール１００重量部に対して０．１〜３０重量部、好ましくは０．３〜２５重量部、さらに好ましくは０．５〜２０重量部程度であり、１〜２０重量部程度である場合が多い。（Ｂ）重合性化合物の割合が少ないと、ポリアセタールの変性度が小さく、過多であると、重合性化合物の種類によっては、ポリアセタールの機械的特性などが低下する場合がある。
【００５６】
（Ａ）ポリアセタールに対する（Ｃ）ラジカル発生剤の割合は、ポリアセタールの過度の低分子量化を抑制でき、かつ変性効率を損わない範囲から選択でき、例えば、（Ａ）ポリアセタール１００重量部に対して３．５重量部以下（例えば、０．０１〜３．５重量部程度）、好ましくは０．０１〜３重量部、さらに好ましくは０．０１〜１．５重量部程度であり、０．０５〜０．５重量部程度である場合が多い。また、（Ａ）ポリアセタールと（Ｂ）重合性化合物との合計量に対する（Ｃ）ラジカル発生剤の割合は、ラジカル発生剤の加工温度における半減期、重合性化合物の量、加工温度、加工時間などに応じて選択でき、（Ａ）ポリアセタールと（Ｂ）重合性化合物との合計１００重量部に対して２．５重量部以下（例えば、０．０１〜２．５重量部程度）、好ましくは０．０１〜２重量部、さらに好ましくは０．０１〜１重量部程度であり、０．０５〜０．５重量部程度である場合が多い。（Ｃ）ラジカル発生剤の使用量が過少であると、（Ｂ）重合性化合物による変性度が低下し易く、過多であってもさほど変性度が向上しない。また、ラジカル発生剤の使用量が多過ぎると、ラジカル発生剤の種類によってはポリセタールの分解が過度に生じる場合がある。
なお、（Ｂ）重合性化合物１００重量部に対する（Ｃ）ラジカル発生剤の割合は、０．１〜２５重量部、好ましくは０．５〜１５重量部、さらに好ましくは１〜１０重量部程度である場合が多い。
【００５７】
ポリアセタールを簡便に変性する方法には、（Ｃ）ラジカル発生剤の存在下、（Ａ）ポリアセタールと（Ｂ）官能基を有する重合性化合物とを、ポリアセタールの溶融状態で混合する方法、特に溶融混練する方法が含まれる。
【００５８】
溶融混合や溶融混練処理には、慣用の混合機や混練機、例えば、押出機、ブラベンダー、ニーダー、バンバリーミキサー、ロールミルなどが利用できる。好ましい溶融混合又は混練機には、押出機、ニーダーなどの密閉式装置が含まれる。混練温度は、ポリアセタールの融点〜分解温度の範囲で選択でき、好ましくはポリアセタールの融点よりも５〜７０℃（好ましくは１０〜５０℃程度）高い温度である。処理時間は、混合又は混練温度に応じて選択でき、例えば、２０秒〜２時間、好ましくは３０秒〜１時間程度であり、３０秒〜３０分程度である場合が多い。
溶融混合又は溶融混練処理は、（Ａ）ポリアセタール、（Ｂ）重合性化合物、および必要に応じて（Ｃ）ラジカル発生剤を、個別に前記混合機や混練機に順次供したり、予め二成分（Ａ）（Ｂ）又は三成分（Ａ）（Ｂ）（Ｃ）の混合物を前記混合機や混練機に供することにより同時に行なってもよい。また、溶融混合又は溶融混練処理は、酸化防止剤の存在下で行なってもよい。
【００５９】
なお、（Ｂ）重合性化合物の不存在下に、（Ａ）ポリアセタールと（Ｃ）ラジカル発生剤とを溶融混合又は溶融混練すると、ラジカル発生剤により、ポリアセタールが著しく低分子量化する。これに対して、（Ｂ）重合性化合物の存在下、（Ａ）ポリアセタールと（Ｃ）ラジカル発生剤とを溶融混合又は溶融混練すると、重合性化合物により変性できるとともに、ラジカル発生剤の量にもよるが、ポリアセタールが過度に低分子量化するのを抑制できる。そのため、（Ａ）ポリアセタールと（Ｃ）ラジカル発生剤との溶融混合物に、（Ｂ）官能基を有する重合性化合物を添加し、ポリアセタールの溶融状態で混合すると、重合性化合物により変性された比較的低分子量の変性ポリアセタールを得ることができる。このような変性ポリアセタールは、相溶化剤や、樹脂、金属、接着剤、塗料などとの密着性改良剤などとして利用できる。
【００６０】
ポリアセタールの分解を抑制しつつ、ラジカル発生剤を変性に有効に利用し、重合性化合物による変性効率を高めるためには、（Ａ）ポリアセタールと（Ｂ）官能基を有する重合性化合物と（Ｃ）ラジカル発生剤との三成分を、ポリアセタールの溶融状態で混合又は混練したり、（Ａ）ポリアセタールと（Ｂ）重合性化合物との共存下、（Ｃ）ラジカル発生剤を添加して、ポリアセタールの溶融状態で混合又は混練する方法、（Ａ）ポリアセタールと（Ｂ）官能基を有する重合性化合物との混合物、特に均一混合物（好ましくはコンパウンド又は溶融混合物）に、（Ｃ）ラジカル発生剤を添加し、ポリアセタールの溶融状態で混合又は混練する方法が有用である。このような方法では、高い分子量とポリアセタールの優れた特性を維持しつつ、重合性化合物の官能基を効率よく導入できる。特に前記方法は、第１の方法に比べて、（Ａ）ポリアセタールの低分子量化を抑制しつつ、変性効率を高めることができるという利点がある。
【００６１】
このような方法は、例えば、前記押出し機などの装置に前記三成分やコンパウンドを供給したり、装置内でポリアセタールと重合性化合物とを溶融混合した後、ラジカル発生剤を装置内に添加又は注入し、混合又は混練することにより行なうことができる。また、前記コンパウンドとラジカル発生剤との混合物を前記装置に供給し、混合又は混練してもよい。前記コンパウンドは、粉粒状又はペレット状で使用する場合が多い。
【００６２】
さらに、重合性化合物による変性度およびラジカル発生剤の利用効率を高めるため、前記の溶融混合又は溶融混練は、補強性充填剤などの充填剤の非存在下で行なうのが好ましい。すなわち、充填剤の存在下で溶融混合又は溶融混練すると、ポリアセタールに対する重合性化合物の変性効率と溶融粘度とを制御するのが困難である場合が多い。これに対して、充填剤及び補強剤の非存在下で変性すると、ラジカル発生剤及び重合性化合物をポリアセタールの変性に有効に利用できるとともに、比較的多量に使用される充填剤及び補強剤により改質されていないので、変性ポリアセタールと種々の熱可塑性樹脂とを組み合わせることにより、幅広い組成物を得ることができる。
【００６３】
なお、必要に応じて、添加剤、例えば、酸化防止剤などの安定化剤を含む樹脂組成物を上記の溶融混合又は溶融混練操作に供してもよい。その際、重合性化合物によるポリアセタールの変性効率、およびラジカル発生剤の利用効率を高めるため、添加剤の添加量は少ない方が好ましく、例えば、ポリアセタールと重合性化合物との合計量１００重量部に対して、１０重量部以下、好ましくは０．００１〜５重量部、さらに好ましくは０．０１〜３重量部程度である。
【００６４】
前記添加剤のうち酸化防止剤の添加は、変性ポリアセタールの安定性を高める上で有用である。前記酸化防止剤には、例えば、ヒンダードフェノール類、ヒンダードアミン類、その他の化合物が含まれる。ヒンタードフェノール類には、例えば、２，６−ジ−ｔ−ブチル−ｐ−クレゾール、２，２′−メチレンビス（４−メチル−６−ｔ−ブチルフェノール）、４，４′−メチレンビス（２，６−ジ−ｔ−ブチルフェノール）、４，４′−ブチリデンビス（３−メチル−６−ｔ−ブチルフェノール）、１，６−ヘキサンジオール−ビス［３−（３，５−ジ−ｔ−ブチル−４−ヒドロキシフェニル）プロピオネート］、ペンタエリスリトールテトラキス［３−（３，５−ジ−ｔ−ブチル−４−ヒドロキシフェニル）プロピオネート］、トリエチレングリコール−ビス［３−（３−ｔ−ブチル−５−メチル−４−ヒドロキシフェニル）プロピオネート］、１，３，５−トリメチル−２，４，６−トリス（３，５−ジ−ｔ−ブチル−４−ヒドロキシベンジル）ベンゼン、ｎ−オクタデシル−３−（４′，５′−ジ−ｔ−ブチルフェノール）プロピオネート、ステアリル−β−（３，５−ジ−ｔ−ブチル−４−ヒドロキシフェノール）プロピオネート、ジステアリル−３，５−ジ−ｔ−ブチル−４−ヒドロキシベンジルホスホネート、２−ｔ−ブチル−６−（３−ｔ−ブチル−５−メチル−２−ヒドロキシベンジル−４−メチルフェニルアクリレート、Ｎ，Ｎ′−ヘキサメチレンビス（３，５−ジ−ｔ−ブチル−４−ヒドロキシ−ヒドロシンナマミド）、３，９−ビス｛２−［３−（３−ｔ−ブチル−４−ヒドロキシ−５−メチルフェニル）プロピオニルオキシ］−１，１−ジメチルエチル｝−２，４，８，１０−テトラオキサスピロ［５，５］ウンデカン、４，４′−チオビス（３−メチル−６−ｔ−ブチルフェノール）、１，１，３−トリス（２−メチル−４−ヒドロキシ−５−ｔ−ブチルフェノール）ブタンなどが含まれる。
【００６５】
ヒンダードアミン類には、例えば、４−アセトキシ−２，２，６，６−テトラメチルピペリジン、４−ステアロイルオキシ−２，２，６，６−テトラメチルピペリジン、４−アクリロイルオキシ−２，２，６，６−テトラメチルピペリジン、４−メトキシ−２，２，６，６−テトラメチルピペリジン、４−ベンゾイルオキシ−２，２，６，６−テトラメチルピペリジン、４−シクロヘキシルオキシ−２，２，６，６−テトラメチルピペリジン、４−フェノキシ−２，２，６，６−テトラメチルピペリジン、４−ベンジルオキシ−２，２，６，６−テトラメチルピペリジン、４−（フェニルカルバモイルオキシ）−２，２，６，６−テトラメチルピペリジン、ビス（２，２，６，６−テトラメチル−４−ピペリジル）オキザレート、ビス（２，２，６，６−テトラメチル−４−ピペリジル）マロネート、ビス（２，２，６，６−テトラメチル−４−ピペリジル）アジペート、ビス（２，２，６，６−テトラメチル−４−ピペリジル）セバケート、ビス（１，２，２，６，６−ペンタメチル−４−ピペリジル）セバケート、ビス（１，２，２，６，６−ペンタメチル−４−ピペリジル）アジペート、ビス（２，２，６，６−テトラメチル−４−ピペリジル）テレフタレート、１，２−ビス（２，２，６，６−テトラメチル−４−ピペリジルオキシ）エタン、ビス（２，２，６，６−テトラメチル−４−ピペリジル）ヘキサメチレン−１，６−ジカルバメート、トリス（２，２，６，６−テトラメチル−４−ピペリジル）ベンゼン−１，３，５−トリカルボキシレート、フェニル−α−ナフチルアミン、フェニル−β−ナフチルアミン、Ｎ，Ｎ′−ジフェニル−ｐ−フェニレンジアミン、Ｎ−フェニル−Ｎ′−シクロヘキシル−ｐ−フェニレンジアミン、Ｎ−イソプロピル−Ｎ′−フェニル−ｐ−フェニレンジアミンなどが挙げられる。
【００６６】
その他の酸化防止剤には、例えば、ジミリスチルチオジプロピオネート、ジラウリルチオジプロピオネート、ジステアリルチオジプロピオネートなどのイオウ系酸化防止剤；トリイソデシルホスファイト、トリフェニルホスファイトなどのリン系酸化防止剤；２，５−ジ−ｔ−ブチルヒドロキノン、２，５−ジアミルヒドロキノンなどののヒドロキノン系酸化防止剤；６−エトキシ−２，２，４−トリメチル−１，２−ジヒドロキノリンなどのキノリン系酸化防止剤；メルカプトヘンゾイミダゾールなどが含まれる。
これらの酸化防止剤は一種又は二種以上併用することができる。好ましい酸化防止剤には、ヒンダードフェノール類（フェノール系酸化防止剤）、ヒンダードアミン類（アミン系酸化防止剤）が含まれる。
【００６７】
酸化防止剤の共存下でポリアセタールを変性する場合、酸化防止剤は（Ａ）ポリアセタール又は変性過程で添加してもよい。酸化防止剤の使用量は、（Ａ）ポリアセタール１００重量部に対して、０．００１〜２重量部、好ましくは０．０１〜１重量部程度である。
このようにして得られた変性ポリアセタールは、必要に応じてペレット化してもよい。
【００６８】
前記変性ポリアセタールは、前記重合性化合物の官能基の種類やその量に応じて、ポリアセタール（１）のみならず、前記コアシェルポリマー（２）に対して高い親和性、相溶性を有している。そのため、ポリアセタール（１）と、このポリアセタールに対して非相溶のコアシェルポリマーを含んでいても、ポリアセタール（１）にコアシェルポリマー（２）の特性を有効に付与して、特に耐衝撃性やウェルド強度及びウェルド伸度の高い樹脂組成物を得ることができる。
【００６９】
変性ポリアセタール（３）の割合は、ポリアセタール（１）およびコアシェルポリマー（２）の種類やその割合などに応じて、例えば、ポリアセタール（１）およびコアシェルポリマー（２）の総量／変性ポリアセタール（３）＝５０／５０〜９９／１（重量比）、好ましくは７０／３０〜９９／１（重量比）、さらに好ましくは８０／２０〜９７／３（重量比）程度であり、７０／３０〜９０／１０（重量比）程度である場合が多い。
【００７０】
本発明のポリアセタール樹脂組成物は、種々の方法、例えば、ポリアセタール（１）とコアシェルポリマー（２）と変性ポリアセタール（３）とを溶融状態で混合することによりポリアセタール樹脂組成物を製造する場合が多い。溶融状態で混合する場合、慣用の混合機や混練機、例えば、押出し機、ブラベンダー、ニーダー、バンバリーミキサー、ロールミキサーなどが利用できる。好ましい溶融混合又は混練機には、押出し機、ニーダーなどの密閉式装置が含まれる。
混合温度は、コアシェルポリマー（２）の種類に応じて、ポリアセタール（１）および変性ポリアセタール（３）のそれぞれの溶融可能な温度の下限（例えば、融点）から分解温度までの温度範囲のうち、重複する温度範囲、例えば、１００〜２４０℃、好ましくは１３０〜２３０℃、さらに好ましくは１６０〜２２０℃程度の範囲から適当に選択できる。
【００７１】
また、（３）変性ポリアセタールを、前記のように溶融混合により製造する場合、ポリアセタールと重合性化合物との溶融混合系に、ポリアセタール（１），コアシェルポリマー（２）を共存させることにより、ポリアセタール（１）、コアシェルポリマー（２）および変性ポリアセタール（３）で構成された本発明の組成物を得ることも可能である。
【００７２】
また、変性ポリアセタールは、前記重合性化合物の官能基の種類やその量に応じて、補強剤や充填剤に対しても高い親和性、相溶性や濡れ性を示す。そのため、本発明において、さらに補強剤や充填剤などを含む樹脂組成物も好ましい。補強剤には、例えば、有機繊維（例えば、ポリプロピレン繊維、ビニロン繊維、ポリアクリロニトリル繊維、ポリアミド繊維、アラミド繊維、ポリエステル繊維など）、無機繊維（ガラス繊維、アルミナ繊維、炭素繊維、金属繊維など）や、ホイスカー（例えば、アルミナ、酸化ベリリウム、炭化ホウ素、炭化ケイ素、窒化ケイ素などのホイスカー）などが挙げられる。これらの補強剤は一種又は二種以上使用できる。
充填剤としては、例えば、アルミナ、シリカ、カオリン、クレイ、ガラス、酸化亜鉛、酸化マグネシウム、酸化ジルコニウム、酸化チタン、水酸化アルミニウム、炭酸カルシウム、炭酸マグネシウム、硫酸バリウム、チタン酸カリウム、二硫化モリブデン、カーボン、黒鉛、金属粉などが例示される。これらの充填剤も一種又は二種以上使用できる。
補強剤と充填剤との使用量は、補強剤や充填剤の種類に応じて、それぞれ成形性などの特性を損なわない範囲で選択でる。
さらに、樹脂組成物は、必要に応じて、酸化防止剤、紫外線吸収剤などの安定化剤、帯電防止剤、滑剤、難燃剤、着色剤などの添加剤を含んでいてもよい。なお、酸化防止剤は、変性ポリアセタールに添加してもよい。
本発明の熱可塑性樹脂組成物は、成形加工により種々の成形品を得る上で有用である。成形品は、慣用の方法、例えば、射出成形、押し出し成形などにより得ることができる。
【００７３】
【発明の効果】
本発明の樹脂組成物は、ポリアセタールにコアシェルポリマーと変性ポリアセタールを混合することにより、コアシェルポリマーの特性をポリアセタールに有効に付与でき、高い耐衝撃性とウェルド強度・伸度を有するポリアセタール樹脂組成物を得ることができる。
本発明の方法では、ポリアセタールとコアシェルポリマーと変性ポリアセタールとを混合するという簡単な操作で、前記の如き高い特性を有する樹脂組成物を効率よく得ることができる。
【００７４】
【実施例】
以下に、実施例に基づいて本発明をより詳細に説明するが、本発明はこれらの実施例により限定されるものではない。
［コアシェルポリマーの調製］
調製例１（コアシェルポリマーＡの調製）
還流冷却器付重合容器（容量５リットル）に、脱イオン水３２０ｇ、ポリオキシエチレンノニルフェニルエーテル（花王（株）製，エマルゲン９５０）の１０重量％水溶液６６ｇを仕込み、窒素気流下で撹拌しながら７０℃に昇温した。下記の組成からなる一段目モノマー混合物７７ｇを添加し、１０分間分散させた後、２，２−アゾビス（２−アミノプロパン）二塩酸塩（和光純薬（株）製，Ｖ−５０）の２重量％水溶液１５４ｇを添加し、重合することによりシード粒子を生成させた。
［一段目モノマー混合物の組成］
ｎ−ブチルアクリレート １５３３．８４ｇ
アリルメタクリレート ３．０８ｇ
１，４−ブチレングリコールジアクリレート ３．０８ｇ
次に、一段目モノマー混合物の残り１４６３ｇにポリオキシエチレンノニルフェニルエーテル（花王（株）製，エマルゲン９５０）の１０重量％水溶液４４０ｇ，脱イオン水４４０ｇを添加混合した乳化液を１８０分間に亘り連続的にフィードし重合した。
【００７５】
温度７０℃で１時間熟成した後、二段目の重合に入った。すなわち、２，２−アゾビス（２−アミノプロパン）二塩酸塩（和光純薬（株）製，Ｖ−５０）の２重量％水溶液６６ｇを添加し、下記の組成の二段目モノマー乳化液１１２０ｇを６０分間に亘り連続的にフィードし、シード重合した。
［二段目モノマー乳化液の組成］
メチルメタクリレート ５９４．０ｇ
エチルアクリレート ６６．０ｇ
ポリオキシエチレンノニルフェニルエーテル
（エマルゲン９５０） ２２０．０ｇ
脱イオン水 ４４０．０ｇ
反応温度を８０℃に昇温して１時間熟成した後、冷却して、３００メッシュのステンレス金網で濾過し、コアシェルポリマーラテックスを得た。このラテックスを−１５℃にて凍結させ、グラスフィルターで濾過した後、６０℃にて一昼夜送風乾燥して、コアシェルポリマーＡを得た。
【００７６】
調製例２〜６（コアシェルポリマーＢ〜Ｆ）
表１に示したモノマー組成で、調製例１と同様の方法によりコアシェルポリマーＢ〜Ｆを得た。なお、コアシェルポリマーＣについては、得られたポリマーを２軸押出機を用いて、減圧下、シリンダー温度２２０℃、ダイヘッド２３０℃で加熱し、ジカルボン酸の脱水処理により酸無水基を導入したコアシェルポリマーを得た後、後述のポリアセタール樹脂組成物の作製に用いた。
【００７７】
表１におけるモノマーの略号の意味は次の通りである。
ＢＡ：ｎ−ブチルアクリレート
ＡｌＭＡ：アリルメタクリレート
ＢＧＭ：１，４−ブチレングリコールジアクリレート
ＭＭＡ：メチルメタクリレート
ＥＡ：エチルアクリレート
ＭＡＡ：メタクリル酸
ＩＡ：イタコン酸
ＧＭＡ：グリシジルメタクリレート
ＨＥＭＡ：２−ヒドロキシエチルメタクリレート
ＭＡＭ：メタクリル酸アミド。
【００７８】
【表１】

［変性ポリアセタールの調製］
調製例７（変性ポリアセタール１の調製）
（Ａ）ポリアセタール［ポリプラスチックス（株）製、商品名ジュラコンＭ２５、ポリアセタールコポリマー、メルトフローレート２．５ｇ／１０分（１９０℃，２．１６ｋｇ）］９５重量部および（Ｂ）重合性化合物［Ｎ−［４−（２，３−エポキシプロポキシ）−３，５−ジメチルベンジル］アクリルアミド（鐘淵化学工業（株）製、商品名 ＡＸＥ）］５重量部（ポリアセタール１００重量部に対して５．３重量部）をドライブレンドした後、二軸押出機にて１９０℃の温度で約２分間溶融混練し、ペレットを得た。得られたペレットと（Ｃ）ラジカル発生剤［α，α′−ビス（ｔ−ブチルパーオキシ−ｍ−イソプロピル）ベンゼン（日本油脂（株）製、商品名パーブチルＰ）］０．１重量部（ポリアセタール１００重量部に対して０．１１重量部）とをドライブレンドした後、再び二軸押出機にて１９０℃の温度で約２分間溶融混練し、変性ポリアセタールのペレットを得た。
【００７９】
重合性化合物による変性量は、１．９重量％であった。なお、変性量は次のようにして測定した。ポリアセタールに結合しなかった（Ｂ）重合性化合物を除去するため、変性ポリアセタールを再沈法により精製し、プロトンＮＭＲにより、ポリアセタールへ導入された（Ｂ）重合性化合物を定量し、重合性化合物による変性量を、ポリアセタール成分に対する割合として、重量％で表示した。なお、再沈は、変性ポリアセタール１５０ｍｇとヘキサフルオロイソプロパノール４ｍｌとの溶液を、再沈用溶媒（アセトン）中に滴下し、析出したポリマーを濾過により回収した。この操作を３回以上繰り返すことにより、変性ポリアセタールを精製した。
【００８０】
調製例８（変性ポリアセタール２の調製）
前記調製例７において、ポリアセタール１００重量部に対して重合性化合物［グリシジルメタクリレート（東京化成工業（株）］５．３重量部を用いる以外、調製例７と同様にして変性ポリアセタールを得た。重合性化合物による変性量は、１．５重量％であった。なお、再沈による精製に際して、再沈用溶媒としてクロロホルムを用いた。
【００８１】
調製例９（変性ポリアセタール３の調製）
前記調製例７において、ポリアセタール１００重量部に対して重合性化合物［無水マレイン酸（東京化成工業（株）］５．３重量部を用いる以外、調製例７と同様にして変性ポリアセタールを得た。重合性化合物による変性量は、２．０重量％であった。なお、再沈による精製に際して、再沈用溶媒としてクロロホルムを用いた。
【００８２】
調製例１０（変性ポリアセタール４の調製）
前記調製例７において、ポリアセタール１００重量部に対して重合性化合物［２−ビニル−２−オキサゾリン（特開昭６３−１０７７３号公報に記載の方法に従って合成した）］５．３重量部を用いる以外、調製例７と同様にして変性ポリアセタールを得た。重合性化合物による変性量は、１．３重量％であった。なお、再沈による精製に際して、再沈用溶媒としてクロロホルムを用いた。
【００８３】
調製例１１（変性ポリアセタール５の調製）
３．３重量％の１，３−ジオキソラン、０．８重量％のアリルグリシジルエーテルおよび１００ｐｐｍのメチラールを含有するトリオキサンに、三フッ化ホウ素をトリオキサンに対して６０ｐｐｍ添加してカチオン重合し、重合性ポリアセタールを調製した。
前記調製例７において、ポリアセタールに代えて、上記重合性ポリアセタールを用いる以外、調製例７と同様にして、変性ポリアセタールを得た。重合性化合物による変性量は、３．１重量％であった。
【００８４】
実施例１〜６および比較例１、２
上記調製例で得られた変性ポリアセタール１〜５と、コアシェルポリマーＡ及びＢと、ポリアセタール（ポリプラスチックス（株）製，ジュラコンＭ９０）とを表２に示す割合でドライブレンドした後、二軸押出し機にて１９０℃で溶融混練し、ペレット化した。このペレットを射出成形機により成形し、衝撃試験片及びゲートを両端に有するウェルド試験片を作製した。ＡＳＴＭ Ｄ２５６に準じてアイゾット衝撃強度を測定した。また、ＡＳＴＭ Ｄ６３８に準じて、得られた試験片のウェルド強度およびウェルド伸度を測定した。結果を表２に示す。
【００８５】
【表２】

表２より、比較例の樹脂組成物に比べて、変性ポリアセタールを含む実施例の樹脂組成物を用いると、耐衝撃性、ウェルド強度および伸度を大きく改善できる。
【００８６】
実施例７〜１１および比較例３、４
上記調製例で得られた変性ポリアセタール１と、コアシェルポリマーＢと、ポリアセタール（ポリプラスチックス（株）製，ジュラコンＭ９０）とを表３に示す割合で用い、前記実施例と同様にして調製した試験片のアイゾット衝撃強度、ウェルド強度およびウェルド伸度を測定したところ、表３に示す結果を得た。
【００８７】
【表３】

表３より、比較例の樹脂組成物に比べて、変性ポリアセタールを含む実施例の樹脂組成物は、衝撃強度、ウェルド強度および伸度が大きい。
【００８８】
実施例１２〜１５および比較例５〜８
上記調製例で得られた変性ポリアセタール１、３及び５と、コアシェルポリマーＣ〜Ｆと、ポリアセタール（ポリプラスチックス（株）製，ジュラコンＭ９０）とを表４に示す割合で用いる以外、前記実施例と同様にして調製した試験片のアイゾット衝撃強度、ウェルド強度およびウェルド伸度を測定したところ、表４に示す結果を得た。
【００８９】
【表４】

表４より、比較例の樹脂組成物に比べて、変性ポリアセタールを含む実施例の樹脂組成物は、衝撃強度、ウェルド強度および伸度が大きい。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a polyacetal resin composition capable of improving the affinity between a polyacetal and a core-shell polymer and improving properties such as impact resistance and a method for producing the same.
[0002]
[Prior art]
Since polyacetal has excellent mechanical strength, slidability, heat resistance, chemical resistance, moldability, and electrical properties, it is used in a wide range of engineering plastics. However, as the field of application of polyacetal expands, further improvements in material properties are required. For example, a molded part having a complicated shape used for an automobile or the like is required to have high impact resistance and strength.
[0003]
As a technique for improving the impact resistance of polyacetal, a conventional method of adding a thermoplastic polyurethane (for example, JP-A-59-145243 and JP-A-61-19652), an acrylic multiphase interpolymer ( A method of adding a core-shell polymer) (for example, JP 59-136343 A) has been proposed. Although these methods are in the direction of improvement in terms of impact resistance, they have not fully satisfied the recent requirements for high-level characteristics. For example, although the impact resistance is improved by the former method of adding thermoplastic polyurethane, the strength and elongation of the welded portion of the molded product are remarkably lowered, and the design of the molded product is greatly limited. In addition, the latter method of adding an acrylic multiphase interpolymer has higher strength and elongation of the weld part of the molded product than the former, but does not necessarily satisfy the requirements for advanced properties, and has an impact resistance. Further improvements are also needed.
[0004]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to provide a polyacetal resin composition capable of effectively imparting the properties of a core-shell polymer to polyacetal.
Another object of the present invention is to provide a resin composition having high impact resistance and weld strength / elongation in the composite of polyacetal and core-shell polymer.
Still another object of the present invention is to provide a method for producing a polyacetal resin composition capable of efficiently obtaining a resin composition having the above-mentioned high properties by a simple operation.
[0005]
[Means for Solving the Problems]
As a result of intensive studies to achieve the above-mentioned object, the present inventors have determined that, in a polyacetal resin composition containing a core-shell polymer, the characteristics of the resin composition are related to the dispersibility of the core-shell polymer. By adding a modified polyacetal modified with a functional compound to a polyacetal / core-shell polymer resin composition, the core-shell polymer is uniformly dispersed to obtain a polyacetal resin composition having high impact resistance, weld strength and elongation. As a result, the present invention has been completed.
[0006]
That is, the present invention provides polyacetal (1), Includes alkyl acrylate units having 2 to 8 carbon atoms in the alkyl group With rubbery polymer core , Core-shell polymer having a glassy polymer shell -( 2) as an epoxy group, carboxyl group, acid anhydride group, ester group, hydroxyl group, ether group, amide group, amino group, nitrile group, isocyanate group, imide group, cycloalkyl group, aryl group, and hetero atom A polyacetal resin composition comprising a modified polyacetal (3) in which a residue of a polymerizable compound having at least one functional group selected from the group consisting of heterocyclic groups having a nitrogen atom is introduced into the polyacetal component, and the same It relates to a manufacturing method.
In the present specification, unless otherwise specified, “polyacetal” means an unmodified polyacetal homopolymer or polyacetal copolymer, and “thermoplastic resin” means a thermoplastic resin other than polyacetal and modified polyacetal. . Further, the “residue of the polymerizable compound” is not limited to the monomer unit of the polymerizable compound, but also means a polymer (for example, a dimer, trimer, tetramer or polymer component generated by polymerization). Further, the “non-self-condensable functional group” means a functional group that can be condensed without intervening reaction components, such as a methylol group. Further, unless otherwise specified, acrylic monomers and methacrylic monomers are collectively referred to as “(meth) acrylic monomers”.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is described in detail below.
The contents of the polyacetal (1), the core-shell polymer (2) and the modified polyacetal (3) constituting the resin composition of the present invention are as follows.
[0008]
(1) Polyacetal
Polyacetal (polyacetal component) is an oxymethylene group (-CH ₂ It is a polymer compound containing O-) as a main structural unit. Polyacetals include polyoxymethylene homopolymers and polyacetal copolymers. In addition to the oxymethylene group, this copolymer has an oxyalkylene unit having about 2 to 6 carbon atoms, preferably about 2 to 4 carbon atoms (for example, an oxyethylene group (-CH ₂ CH ₂ O-), an oxypropylene group, an oxytetramethylene group, and the like) as structural units. The proportion of the oxyalkylene group having about 2 to 6 carbon atoms can be appropriately selected depending on the use of the polyacetal, for example, 0.1 to 30 mol%, preferably about 1 to 20 mol% with respect to the whole polyacetal. It is.
[0009]
The polyacetal copolymer may be composed of a plurality of components such as a copolymer composed of two components, a terpolymer composed of three components, or a block copolymer. Further, the polyacetal may have a branched structure as well as a linear structure, and may have a crosslinked structure. Furthermore, the terminal of the polyacetal may be stabilized, for example, by esterification with a carboxylic acid such as acetic acid, propionic acid, or butyric acid. The polymerization degree, branching degree, and crosslinking degree of the polyacetal are not particularly limited as long as it can be melt-molded.
[0010]
Preferred polyacetals include polyoxymethylene, polyacetal copolymers (eg, copolymers composed of at least oxymethylene units and oxyethylene units). From the viewpoint of thermal stability, a polyacetal copolymer is preferred.
The molecular weight of the polyacetal is not particularly limited, and is, for example, about 5,000 to 500,000, preferably about 10,000 to 400,000.
[0011]
The polyacetal can be produced, for example, by polymerizing aldehydes such as formaldehyde, paraformaldehyde, and acetaldehyde, and cyclic ethers such as trioxane, ethylene oxide, propylene oxide, and 1,3-dioxolane.
[0012]
(2) Core shell polymer
The core-shell polymer is a polymer having a rubbery polymer (rubber elastic body) or a rubbery polymer phase core and a glassy polymer shell in the outermost layer, and uses a monomer, a surfactant, a polymerization initiator, and water. It can be produced by a known method. The core-shell polymer is usually obtained by a seed emulsion polymerization method, for example, a continuous multi-stage emulsion polymerization method in which the polymer produced in the preceding stage is sequentially coated with the polymer in the subsequent stage. When the core-shell polymer has an intermediate phase to be described later, the intermediate phase may be formed by a multistage emulsion polymerization method in which the polymer produced in the preceding stage enters the polymer produced in the subsequent stage.
JP-A-3-14856, JP-A-5-271361, and the like can be referred to for the production of the core-shell polymer by the seed emulsion polymerization method.
[0013]
In the multi-stage emulsion polymerization, the first stage polymerization is a reaction to form a rubbery polymer. As the monomer constituting the rubbery polymer, various polymerizable monomers that form a rubber elastic body, such as glass transition temperature − A polymerizable monomer that forms a rubber elastic body of 30 ° C. or lower (for example, about −40 ° C. to −100 ° C.) can be used, and examples thereof include conjugated dienes, alkyl acrylates having 2 to 8 carbon atoms, and mixtures thereof. . Examples of such conjugated dienes include butadiene, isoprene, chloroprene, and butadiene is particularly preferably used. Examples of the alkyl acrylate having 2 to 8 carbon atoms in the alkyl group include ethyl acrylate, propyl acrylate, butyl acrylate, hexyl acrylate, cyclohexyl acrylate, and 2-ethylhexyl acrylate, and ethyl acrylate and butyl acrylate are particularly preferably used. .
In the first stage polymerization, monomers copolymerizable with conjugated dienes and alkyl acrylates, for example, aromatic vinyl such as styrene, vinyl toluene, α-methyl styrene, aromatic vinylidene, acrylonitrile, methacrylonitrile, etc. Alkyl methacrylates such as vinyl cyanide, vinylidene cyanide, methyl methacrylate, ethyl methacrylate, and butyl methacrylate may be copolymerized.
In the first-stage polymerization for forming the core, when the monomer does not contain a conjugated diene, or when it contains a conjugated diene but not more than 20% by weight of the total amount of monomers, the crosslinking monomer and grafting By using a small amount of monomer, high impact resistance can be achieved. Examples of the crosslinkable monomer include aromatic divinyl monomers such as divinylbenzene, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate, hexanediol di (meth) acrylate, neo Examples include alkane polyol poly (meth) acrylates such as pentyl glycol di (meth) acrylate, oligoethylene glycol di (meth) acrylate, trimethylolpropane di (meth) acrylate, and trimethylolpropane tri (meth) acrylate. These crosslinkable monomers can be used alone or in admixture of two or more. Preferred crosslinkable monomers include butylene glycol di (meth) acrylate, hexanediol di (meth) acrylate, and the like. Examples of the grafting monomer include unsaturated carboxylic acid allyl esters such as allyl (meth) acrylate, diallyl malate, diallyl fumarate, diallyl itaconate, and allyl methacrylate is preferably used. Such a crosslinkable monomer and a grafting monomer are used in a range of, for example, about 0 to 5% by weight, preferably about 0.1 to 2% by weight, based on the total amount of monomers constituting the core.
[0014]
The outermost shell is formed with a glassy polymer, and the glass transition temperature of the glassy polymer is, for example, 40 ° C or higher (for example, about 50 to 120 ° C), preferably 60 ° C or higher (for example, 70 to 120 ° C). Degree). As the monomer constituting the glassy polymer, a hard monomer that forms the polymer having the glass transition temperature, for example, C such as methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, etc. _1-4 Mention may be made of alkyl-methacrylates and monomers copolymerizable with these methacrylates. C _1-4 Of the alkyl-methacrylates, methyl methacrylate is preferred. C _1-4 Examples of monomers copolymerizable with alkyl methacrylate include alkyl acrylates such as ethyl acrylate and butyl acrylate, aromatic vinyls such as styrene, vinyl toluene, and α-methyl styrene, aromatic vinylidene, acrylonitrile, and methacrylonitrile. And vinyl monomers such as vinyl cyanide and vinylidene cyanide. Preferred copolymerizable monomers include ethyl acrylate, styrene, acrylonitrile and the like. These monomers are C _1-4 Alkyl-methacrylate (such as methyl methacrylate) alone or C _1-4 Used as a mixture of an alkyl-methacrylate (such as methyl methacrylate) and a copolymerizable monomer.
[0015]
In the polyacetal resin composition of the present invention, by introducing functional groups such as carboxyl group, acid anhydride group, epoxy group, amide group and hydroxyl group into the shell of the core-shell polymer, the characteristics of the polyacetal and core-shell polymer are effectively expressed. it can. Introduction of these functional groups into the shell can be carried out by copolymerization of a monomer constituting the shell and a polymerizable monomer having the functional group, or by treatment of the produced polymer.
[0016]
Examples of the polymerizable monomer having a carboxyl group include acrylic acid, methacrylic acid, and unsaturated dicarboxylic acid. Examples of the unsaturated dicarboxylic acid include maleic acid, fumaric acid, itaconic acid, citraconic acid, mesaconic acid, aconitic acid, and methylmalonic acid, and itaconic acid is preferred.
The introduction of an acid anhydride group includes various methods such as heat-drying a core-shell polymer in which an unsaturated dicarboxylic acid residue is introduced into a shell by copolymerization under an inert gas atmosphere, heat treatment through an extruder, and the use of a dehydrating agent. The dehydration treatment can be carried out by the above method to convert at least a part of the carboxyl groups into acid anhydride groups.
Examples of the polymerizable monomer having an epoxy group include glycidyl (meth) acrylate, and glycidyl methacrylate is often used.
Examples of the polymerizable monomer having a hydroxyl group include hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate, and hydroxyethyl methacrylate is preferably used.
The amount of the polymerizable monomer having a functional group is, for example, 0.1 to 20% by weight, preferably 0.5 to 15% by weight, more preferably 1 to 10% by weight, based on the whole monomer constituting the shell. Degree.
[0017]
The ratio between the core made of the rubber-like polymer and the shell made of the glass-like polymer can be selected within a range not impairing the impact resistance. For example, core / shell = 40/60 to 95/5 (weight) %), Preferably 50/50 to 90/10 (% by weight), more preferably about 60/40 to 80/20 (% by weight).
[0018]
In the core-shell polymer, an intermediate phase may exist between the core and the shell. The intermediate phase forms various polymerizable compounds, for example, polymerizable monomers having functional groups such as glycidyl (meth) acrylate, (meth) acrylic acid, hydroxyethyl (meth) acrylate, and glassy polymers such as methyl methacrylate. It can be formed by polymerizing a polymerizable monomer, a polymerizable monomer that forms a rubbery polymer such as butyl acrylate, and the like at an appropriate stage of seed multistage emulsion polymerization. The intermediate phase can be variously selected according to the properties of the desired core-shell polymer, and the proportion of the polymerizable monomer that forms the intermediate phase can also be appropriately selected according to the polymerizable monomer. For example, the entire monomer constituting the core-shell polymer 1 to 50% by weight, preferably 5 to 30% by weight. When the intermediate phase is a glassy polymer, the intermediate phase can be regarded as a part of the shell, and when the intermediate phase is a rubbery polymer, it can be regarded as a part of the core.
[0019]
The structure of the core-shell polymer having such an intermediate phase may be, for example, a multilayer structure in which a layer is interposed between the core and the shell, or a salami structure in which the intermediate phase is dispersed in the form of particles in the core. In a core-shell polymer having a salami structure, in a more extreme case, the dispersed intermediate phase may form a core at the center of the core. The core-shell polymer having such a structure may be formed when an aromatic vinyl monomer typified by styrene is used as a constituent monomer of the intermediate phase. When a core-shell polymer having an intermediate phase is used, in addition to impact resistance, the flexural modulus, thermal deformation temperature and appearance may be improved.
[0020]
In the present invention, the addition amount of the core-shell polymer (2) can be appropriately selected within a range in which the impact resistance of the polyacetal (1) can be improved. For example, polyacetal (1) / core-shell polymer (2) = 99 / 1-60 / 40 (weight ratio), preferably in the range of about 95/5 to 60/40 (weight ratio), and often in the range of about 90/10 to 70/30 (weight ratio). If the addition amount of the core-shell polymer (2) is small, the impact resistance of the polyacetal resin composition may not be improved so much, and if it is too large, the rigidity and heat resistance of the polyacetal resin composition may be impaired.
[0021]
The core-shell polymer can be obtained by polymerizing a monomer by multistage emulsion polymerization in the presence of various emulsifiers such as an anionic surfactant, a cationic surfactant, and a nonionic surfactant. Depending on the type, the stability of the polyacetal (1) and the modified polyacetal (3) may be adversely affected. Therefore, it is advantageous to use a nonionic surfactant as the emulsifier. The nonionic surfactant may be any of a low molecular weight surfactant, an oligomer type surfactant, and a high molecular weight surfactant. Nonionic surfactants include, for example, ethers such as polyoxyethylene alkylphenyl ether (polyoxyethylene nonylphenyl ether, etc.) and polyoxyethylene long chain alkyl ether (polyoxyethylene stearyl ether, polyoxyethylene lauryl ether, etc.). Surfactants, ester surfactants such as polyoxyethylene higher fatty acid esters (such as polyoxyethylene monostearate), sorbitan ester types such as polyoxyethylene sorbitan higher fatty acid esters (such as polyoxyethylene sorbitan monolaurate) Examples thereof include surfactants and block copolymers such as polyoxyethylene polyoxypropylene block copolymers. These surfactants can be used alone or in combination. In addition, you may use a nonionic surfactant in combination with an anionic surfactant, if it is a range which does not impair the stability of polyacetal (1) and modified polyacetal (3).
The amount of the surfactant used can be appropriately selected within a range that does not impair the stability of emulsion polymerization, and can be selected, for example, from a range of about 0.1 to 10% by weight based on the total amount of monomers.
[0022]
Furthermore, as a polymerization initiator in emulsion polymerization, for example, persulfates such as potassium persulfate and ammonium persulfate may be used. In order to increase the stability of polyacetal (1) and modified polyacetal (3), core shell Polymerization initiators that can suppress the introduction of anionic components to the polymer, for example, peroxides such as hydrogen peroxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, azobisisobutyronitrile, 2,2'-azobisiso It is advantageous to use an azo polymerization initiator such as dimethyl butyrate or 2,2'-azobis (2-aminopropane) dihydrochloride. The polymerization initiator may be a redox polymerization initiator composed of the polymerization initiator and a reducing agent.
[0023]
(3) Modified polyacetal
The modified polyacetal can be obtained by using the polyacetal component (that is, polyacetal homopolymer and polyacetal copolymer) described in the section of (1) Polyacetal, or a polymerizable polyacetal and modifying it with a polymerizable compound having a functional group. Hereinafter, “polyacetal” and “polymerizable polyacetal” are sometimes simply referred to as “(A) polyacetal”.
[0024]
The polymerizable polyacetal is an oxymethylene group (—CH ₂ A polymer compound having a main structural unit of O-) and a polymerizable functional group in a polyacetal component. Examples of the polymerizable functional group include an ethylenic double bond and an acetylene bond, and an ethylenically unsaturated bond is particularly preferable.
[0025]
The polymerizable polyacetal has an ethylenically unsaturated bond copolymerized in the presence of a cationically active catalyst using formaldehyde or trioxane as a main monomer and a cyclic ether or cyclic formal having an ethylenically unsaturated bond as a substituent as a comonomer. Polymerized or copolymerized with a cationic polymerization catalyst in the presence of a polyacetal copolymer and a linear formal compound having ethylenically unsaturated bonds as a chain transfer agent with formaldehyde or trioxane as the main monomer. A polyacetal copolymer having an ethylenically unsaturated bond polymerized by anionic polymerization in the presence of a chain transfer agent having formaldehyde as a main monomer and further having a polymerizable functional group such as an ethylenically unsaturated bond. Murrell. In the above polymerization step, a cyclic ether or a cyclic formal having no ethylenically unsaturated bond may coexist as a comonomer as necessary. Further, the polymerizable polyacetal may be a polyacetal obtained by a method using, after the polymerization reaction, a carboxylic acid having a polymerizable functional group or an acid anhydride thereof as a terminal esterifying agent.
[0026]
In the polymerizable polyacetal, the cyclic ether or cyclic formal having an ethylenically unsaturated bond includes, for example, allyl glycidyl ether, vinylbenzyl glycidyl ether, etc., and in the above method, linear chain as a chain transfer agent. Examples of the formal compound include divinyl formal.
In the polymerizable polyacetal, the chain transfer agent having a polymerizable functional group includes alcohols having ethylenically unsaturated bonds such as allyl alcohol and crotonyl alcohol, and alcohols having acetylene bonds such as propargyl alcohol. . Furthermore, in the above method, the carboxylic acid having a polymerizable functional group has, for example, an ethylenically unsaturated bond such as acrylic acid, methacrylic acid, crotonic acid, vinyl glycolic acid, maleic acid, fumaric acid, and itaconic acid. A carboxylic acid having an acetylene bond such as mono- or dicarboxylic acid or propiolic acid can be used. As the carboxylic acid having a polymerizable functional group, acrylic acid or methacrylic acid is often used.
[0027]
In the polymerizable polyacetal, the content of a polymerizable functional group such as an ethylenically unsaturated bond is, for example, about 0.001 to 5 mol / kg, preferably about 0.01 to 2 mol / kg.
Use of the polymerizable polyacetal is preferable because the introduction efficiency of the polymerizable compound described later is increased.
[0028]
The modified polyacetal can be obtained by introducing a residue of a polymerizable compound having a functional group into (A) polyacetal (that is, polyacetal or polymerizable polyacetal). The functional groups of the polymerizable compound include epoxy groups, carboxyl groups, acid anhydride groups, ester groups, hydroxyl groups, ether groups, amide groups, amino groups, nitrile groups, isocyanate groups, imide groups, aryl groups, and heteroatoms. As a heterocyclic group having a nitrogen atom. In addition, the substituent may couple | bond with the nitrogen atom of an amide group and an amino group. The polymerizable compound may be multifunctional having the same or different functional groups in one molecule. These functional groups are useful for enhancing the affinity with the thermoplastic resin (2), additives such as reinforcing agents and fillers. These polymerizable compounds can be used singly or in combination of two or more.
[0029]
The polymerizable compound having a functional group needs to have at least one polymerizable group in one molecule. By adding a small amount of a compound having a plurality of polymerizable groups and modifying it, it is effective for obtaining a resin composition suitable for blow molding or film molding by suppressing excessive crosslinking and suppressing melt viscosity. . When fluidity is required as in an injection molding material, the polymerizable compound contains one polymerizable group (for example, ethylenic double bond, acetylene) in one molecule in order to suppress cross-linking and improve molding processability. Bond), particularly a compound having an ethylenically unsaturated bond. Moreover, even if it is a compound which has a several polymeric group, the polymeric compound which cyclizes within a molecule | numerator and forms a linear polymer like a diarylamine etc. can also be used, for example.
[0030]
Examples of the compound having an epoxy group include glycidyl ethers such as allyl glycidyl ether and chalcone glycidyl ether; glycidyl (meth) acrylate, vinyl benzoic acid glycidyl ester, allyl benzoic acid glycidyl ester, cinnamic acid glycidyl ester, cinnamylidene acetic acid glycidyl ester Glycidyl or epoxy ester such as dimer acid glycidyl ester, ester of epoxidized stearyl alcohol and acrylic acid or methacrylic acid; and epoxidized unsaturated linear or cyclic olefin such as epoxy hexene and limonene oxide. The glycidyl ether type polymerizable compound includes a compound represented by the formula (1) (for example, N- [4- (2,3-epoxypropoxy) -3,5-dimethylbenzyl] as described later. Acrylamide etc.). A preferable polymerizable compound having an epoxy group includes a glycidyl ether type or glycidyl ester type epoxy compound having a (meth) acryloyl group.
[0031]
Examples of the compound having a carboxyl group include aliphatic unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, propiolic acid, and crotonic acid; aromatic unsaturated monocarboxylic acids such as cinnamic acid; maleic acid, fumaric acid, Aliphatic unsaturated dicarboxylic acids such as itaconic acid and citraconic acid; maleic acid monoesters such as monomethyl maleate, monoethyl maleate, monobutyl maleate, monohexyl maleate, monooctyl maleate, mono-2-ethylhexyl maleate and the like And unsaturated dicarboxylic acid monoesters such as the corresponding fumaric acid monoesters. Preferred compounds having a carboxyl group include (meth) acrylic acid, maleic acid, maleic acid monoalkyl ester, and the like.
[0032]
Examples of the compound having an acid anhydride group include maleic anhydride, itaconic anhydride, citraconic anhydride, and hymic anhydride. Preferred compounds having an acid anhydride group include maleic anhydride.
[0033]
Examples of the compound having an ester group include an ester of a polymerizable compound having a carboxyl group such as the unsaturated mono- or dicarboxylic acid or a polymerizable compound having an acid anhydride group and a hydroxy compound having about 1 to 20 carbon atoms. Is included. Examples of the hydroxy compound include carbon numbers such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-methyl-2-propanol, 1-hexanol, 1-octanol, 1-dodecanol, and stearyl alcohol. Examples thereof include aliphatic alcohols having about 1 to 20 (preferably about 4 to 20 carbon atoms), alicyclic alcohols such as cyclohexanol, aralkyl alcohols such as benzyl alcohol, and phenols such as phenol.
Examples of such polymerizable compounds include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, and (meth) acrylic. Isobutyl acid, t-butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, ( (Meth) acrylates such as phenyl (meth) acrylate and benzyl (meth) acrylate; dimethyl maleate, diethyl maleate, dibutyl maleate, dihexyl maleate, dioctyl maleate, di-2-ethylhexyl maleate and the like Unsaturated dicarboxylic acid ester such as fumarate It is included.
The compound having an ester group includes an ester of a polymerizable compound having a hydroxyl group, which will be described later, and an organic carboxylic acid. The compound having an ester group further includes about 2 to 20 carbon atoms (preferably vinyl acetate, vinyl propionate, vinyl butyrate, vinyl caprylate, vinyl laurate, vinyl myristate, vinyl oleate, vinyl stearylate, etc. (preferably Also included are vinyl esters of organic carboxylic acids having about 6 to 20 carbon atoms.
Preferred polymerizable compounds having an ester group include compounds having a relatively high boiling point, for example, (meth) acrylic acid alkyl esters having about 8 to 20 carbon atoms in the alkyl group and about 10 to 20 carbon atoms in the organic carboxylic acid moiety. Vinyl esters are included.
[0034]
Examples of the compound having a hydroxyl group include allyl alcohol, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, butanediol mono (meth) acrylate, hexanediol mono (meth) acrylate, and neopentyl glycol. Examples include mono (meth) acrylate, glycerin mono (meth) acrylate, and vinylphenol. Preferred polymerizable compounds having a hydroxyl group include hydroxyalkyl (meth) acrylate and the like.
Examples of the compound having an ether group include methoxymethyl (meth) acrylate, ethoxymethyl (meth) acrylate, butoxymethyl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, and butoxyethyl (meth). Examples thereof include acrylate and methoxystyrene.
In addition, compounds having a hydroxyl group and an ether group include diethylene glycol mono (meth) acrylate, triethylene glycol mono (meth) acrylate, polyethylene glycol mono (meth) acrylate, dipropylene glycol mono (meth) acrylate, tripropylene glycol mono (Meth) acrylate, polypropylene glycol mono (meth) acrylate, polytetramethylene glycol mono (meth) acrylate and the like.
[0035]
Examples of the compound having an amide group include (meth) acrylamide, methacrylamide, N, N-dimethylacrylamide, N, N-diethylacrylamide, N-isopropylacrylamide, N, N-dimethylaminopropylacrylamide, and siacetoneacrylamide. ) Acrylamide and its derivatives; vinylsulfonamides such as vinylsulfonamide, vinylsulfonanilide, vinylsulfonemethylanilide, vinylsulfonacetanilide and the like are included. Preferred polymerizable compounds having an amide group include (meth) acrylamide and N-substituted (meth) acrylamide.
[0036]
Examples of the compound having an amino group include allyl compounds such as allylamine and diallylamine; vinyl compounds such as 4-vinylaniline and N-vinyldiphenylamine; N, N-dimethylaminoethyl (meth) acrylate and N, N-diethylaminoethyl. Examples include (meth) acrylates such as (meth) acrylate.
[0037]
Examples of compounds having an imide group include maleimides such as maleimide, N-methylmaleimide, N-phenylmaleimide, and bismaleimide and derivatives thereof; N-vinylsuccinimide, N-vinylglutarimide, N-vinylphthalimide, and the like. Vinyl polyvalent carboxylic acid imide and the like are included. Preferred polymerizable compounds having an imide group include maleimide and derivatives thereof.
[0038]
Examples of the compound having a nitrile group include acrylonitrile, methacrylonitrile, and 2-cyanoethyl (meth) acrylate. A preferred polymerizable compound having a nitrile group includes (meth) acrylonitrile.
[0039]
Examples of the compound having an isocyanate group include vinyl isocyanate, methacryloyl isocyanate, and m- (2-isocyano-2-propyl) -α-methylstyrene.
Examples of the compound having a cycloalkyl group or an aryl group include vinylcyclohexane, 2-vinyl-1-nonene, styrene, α-methylstyrene, p-chloromethylstyrene, p-methylstyrene, vinyltoluene, vinylnaphthalene, vinyl. Anthracene etc. are mentioned.
[0040]
As the compound having a heterocyclic group, a compound having a nitrogen atom as a hetero atom, for example, 2-vinylquinoline, 3-vinylpiperidine, 2-vinylpyrazine, 2-vinylpyridine, 4-vinylpyridine, N-vinylpyrrole, N-vinylindole, N-vinylcarbazole, N-vinylimidazole, N-vinyl-2-pyrrolidone, N-vinyl-ε-caprolactam, acryloylmorpholine and the like can be mentioned. Examples of the polymerizable compound having a heterocyclic group include cyclic imino esters such as a compound having an oxazolone group (for example, 2-vinyl-5-oxazolone) and a compound having an oxazoline group (for example, 2-vinyl-2). -Cyclic imino ethers such as oxazoline). Preferred polymerizable compounds having a heterocyclic group include an oxygen atom together with the nitrogen atom as a hetero atom such as a heterocyclic compound in which a vinyl group is bonded to a nitrogen atom as a hetero atom, a cyclic imino ester group, or a cyclic imino ether group. Vinyl compounds having a heterocyclic group are included.
[0041]
Preferred functional groups of the polymerizable compound include, for example, an epoxy group, a carboxyl group, an acid anhydride group, an ester group, a hydroxyl group, an amide group in which the functional group may be bonded to a nitrogen atom, an amino group, a nitrile group, An isocyanate group, an imide group, and the heterocyclic group (a cyclic imino ester group, a cyclic imino ether group, etc.) are included. Preferred amide groups include N-substituted amide groups in which a non-self condensing functional group is bonded to a nitrogen atom.
[0042]
In particular, an ethylenic polymerizable compound having an epoxy group such as glycidyl (meth) acrylate, an ethylenic polymerizable compound having a carboxyl group such as (meth) acrylic acid, and an ethylenic polymerization having an acid anhydride group such as maleic anhydride. Or an ethylenically polymerizable compound having an amide bond and an epoxy group is preferred.
[0043]
The ethylenically polymerizable compound having an epoxy group or an amide bond and an epoxy group includes a compound represented by the following formula (1).
[0044]
[Chemical formula 2]

(Wherein R ¹ Is a hydrogen atom or a methyl group, R ² ~ R ^Five Are the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an alkoxycarbonyl group, an acyl group, or an acyloxy group. n is 0 or 1)
Examples of the halogen atom include fluorine, chlorine, bromine and iodine atoms, and examples of the alkyl group include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, t-butyl, pentyl, hexyl and octyl. An alkyl group having about 1 to 10 carbon atoms such as a group is included. Preferred alkyl groups include lower alkyl groups having about 1 to 6 carbon atoms, particularly about 1 to 4 carbon atoms.
The alkoxy group includes, for example, a lower alkoxy group having about 1 to 6 carbon atoms such as methoxy, ethoxy, propoxy, butoxy, t-butoxy, pentyloxy, hexyloxy group and the like.
Examples of the alkoxycarbonyl group include lower alkoxycarbonyl groups having about 1 to 6 carbon atoms in the alkoxy moiety such as methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, butoxycarbonyl, t-butoxycarbonyl, pentyloxycarbonyl, hexyloxycarbonyl group, etc. In many cases.
The acyl group includes a lower acyl group having about 1 to 6 carbon atoms such as formyl, acetyl, propionyl, butyryl, valeryl and pivaloyl groups. Examples of the acyloxy group include acetyloxy, propionyloxy, butyryloxy, valeryloxy, and pivaloyloxy groups.
R ² ~ R ^Five Are the same or different and are often a hydrogen atom, a halogen atom or a lower alkyl group. Especially R ² ~ R ^Five Are the same or different and are often a hydrogen atom or a lower alkyl group.
[0045]
The compound in which n is 0 includes the glycidyl (meth) acrylate. Specific examples of the compound in which n is 1 include, for example, N- [4- (2,3-epoxypropoxy) phenylmethyl] acrylamide, N- [4- (2,3-epoxypropoxy) -3,5-dimethyl. Benzyl] acrylamide, N- [4- (2,3-epoxypropoxy) -3,5-diethylbenzyl] acrylamide, N- [4- (2,3-epoxypropoxy) -3,5-dibutylbenzyl] acrylamide and the like N- [4- (2,3-epoxypropoxy) -3,5-dialkylbenzyl] acrylamide, N- [4- (2,3-epoxypropoxy) -2,6-dimethylbenzyl] acrylamide, N- [ 4- (2,3-epoxypropoxy) -2,5-dimethylbenzyl] acrylamide, N- [4- (2,3-epoxypropoxy) -2 3,5,6 tetramethyl benzyl] acrylamide are exemplified.
[0046]
In many cases, the polymerizable compound is liquid or solid (non-gaseous) at room temperature and atmospheric pressure. Of these polymerizable compounds, a compound having a boiling point of 70 ° C. or higher, preferably 100 ° C. or higher, more preferably 120 ° C. or higher at normal pressure is often used, and the preferable boiling point of the polymerizable compound is maleic anhydride, (meta ) Acrylic acid, glycidyl (meth) acrylate, a compound represented by the above formula (1) (for example, N- [4- (2,3-epoxypropoxy) -3,5-dimethylbenzyl] acrylamide) and the like. In many cases, it is 140 ° C. or higher at normal pressure.
[0047]
The modified polyacetal is preferably a polyacetal modified with the polymerizable compound in the absence of a filler or a reinforcing agent in order to increase the modification efficiency, the modified polyacetal and the utilization efficiency of the molded product. By using a modified polyacetal modified in the absence of fillers and reinforcing agents, a resin composition can be prepared simply by mixing with a plurality of thermoplastic resins depending on the application, and the degree of freedom of alloying and compounding is increased. growing.
[0048]
The introduction amount of the functional group can be selected within a range in which the affinity with the thermoplastic resin and the additive can be improved. For example, 0.1 to 30% by weight (for example, in terms of a polymerizable compound with respect to (A) polyacetal) 0.1 to 20% by weight), preferably 0.2 to 25% by weight (for example, about 0.2 to 15% by weight), more preferably 0.3 to 20% by weight (for example, 0.3 to 10% by weight). In many cases, it is about 0.2 to 10% by weight.
[0049]
The modified polyacetal can be produced by heating (A) polyacetal and (B) a polymerizable compound having a functional group, and introducing the residue of the polymerizable compound into the polyacetal. (A) The polyacetal and (B) the polymerizable compound having a functional group may be heated in the absence of (C) a radical generator (polymerization initiator), but (C) in the presence of a radical generator. When heated with, the residue of the polymerizable compound can be introduced efficiently.
[0050]
The type of the radical generator (C) is not particularly limited as long as it is a compound that generates a free radical and has a function as a polymerization initiator that initiates polymerization of the polymerizable compound. As the radical generator, peroxides such as organic peroxides, azo compounds, and other radical polymerization initiators can be used.
[0051]
Examples of the peroxide include alkyl hydroperoxides such as t-butyl hydroperoxide, p-menthane hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide; t-butyl peroxide, t-butyl cumyl peroxide, dicumyl peroxide, t-butyl peroxycumene, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl Dialkyl peroxides such as -2,5-di (t-butylperoxy) hexyne-3, α, α'-bis (t-butylperoxy-m-isopropyl) benzene; benzoyl peroxide, lauroyl peroxide, p -Diacyl peroxide such as chlorobenzoyl peroxide Alkylidene peroxides such as methyl ethyl ketone peroxide, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclododecane; n-butyl- Examples thereof include peroxide esters such as 4,4-bis (t-butylperoxy) valerate and t-butylperoxybenzoate.
[0052]
Examples of the azo compound include 1-[(1-cyano-1-methylethyl) azo] formamide, 2,2′-azobis {2-methyl-N- [1,1-bis (hydroxymethyl) ethyl] propion. Amide} compounds; 1,1-azobis (cyclohexane-1-carbonitrile), 2-phenylazo-4-methoxy-2,4-dimethylvaleronitrile, 2,2′-azobis [2- (hydroxymethyl) ) Propionitrile], azonitrile compounds such as azobisisobutyronitrile; and alkylazo compounds such as 2,2′-azobis (2,4,4-trimethylpentane).
[0053]
Examples of other radical generators that can be used include persulfates such as potassium persulfate, sodium persulfate, and ammonium persulfate.
These radical generators may be used alone or in combination of the same or different types.
[0054]
In order to efficiently introduce the functional group of the polymerizable compound (B) into the polyacetal (A), a preferable radical generator has a temperature corresponding to a half-life of 1 minute at 130 ° C or higher, preferably 150 ° C or higher, more preferably Compounds of 160 ° C. or higher are included. Such radical generators are often alkyl hydroperoxides, dialkyl peroxides, peroxide esters, and azo compounds.
[0055]
(B) The ratio of the polymerizable compound having a functional group can be selected according to the desired degree of modification and the use of the modified polyacetal, for example, 0.1 to 30 parts by weight with respect to 100 parts by weight of (A) polyacetal. The amount is preferably about 0.3 to 25 parts by weight, more preferably about 0.5 to 20 parts by weight, and often about 1 to 20 parts by weight. (B) If the ratio of the polymerizable compound is small, the degree of modification of the polyacetal is small, and if it is excessive, the mechanical properties of the polyacetal may be lowered depending on the type of the polymerizable compound.
[0056]
(A) The ratio of the (C) radical generator with respect to polyacetal can be selected from a range in which excessive reduction in molecular weight of polyacetal can be suppressed and modification efficiency is not impaired. For example, with respect to 100 parts by weight of (A) polyacetal 3.5 parts by weight or less (for example, about 0.01 to 3.5 parts by weight), preferably 0.01 to 3 parts by weight, more preferably about 0.01 to 1.5 parts by weight, Often about 0.5 parts by weight. The ratio of (C) radical generator to the total amount of (A) polyacetal and (B) polymerizable compound is the half-life at the processing temperature of the radical generator, the amount of polymerizable compound, the processing temperature, the processing time, etc. The total amount of (A) polyacetal and (B) polymerizable compound is 100 parts by weight or less (for example, about 0.01 to 2.5 parts by weight), preferably 0. 0.01 to 2 parts by weight, more preferably about 0.01 to 1 part by weight, often about 0.05 to 0.5 part by weight. If the amount of the (C) radical generator used is too small, the degree of modification with the polymerizable compound (B) tends to decrease, and the degree of modification does not improve much even if it is excessive. Moreover, when there is too much usage-amount of a radical generator, decomposition | disassembly of polycetal may arise too much depending on the kind of radical generator.
In addition, the ratio of the (C) radical generator with respect to 100 parts by weight of the polymerizable compound (B) is 0.1 to 25 parts by weight, preferably 0.5 to 15 parts by weight, and more preferably about 1 to 10 parts by weight. There are many cases.
[0057]
A method for easily modifying polyacetal is (C) a method in which (A) polyacetal and (B) a polymerizable compound having a functional group are mixed in the presence of a radical generator in the molten state of the polyacetal, particularly melt kneading. How to do.
[0058]
For the melt mixing or melt kneading treatment, a conventional mixer or kneader, for example, an extruder, a brabender, a kneader, a Banbury mixer, a roll mill, or the like can be used. Preferred melt mixing or kneaders include hermetic devices such as extruders and kneaders. The kneading temperature can be selected in the range of the melting point to the decomposition temperature of the polyacetal, and is preferably a temperature higher by 5 to 70 ° C. (preferably about 10 to 50 ° C.) than the melting point of the polyacetal. The treatment time can be selected depending on the mixing or kneading temperature, and is, for example, 20 seconds to 2 hours, preferably about 30 seconds to 1 hour, and often about 30 seconds to 30 minutes.
In the melt mixing or melt kneading treatment, (A) polyacetal, (B) polymerizable compound, and (C) radical generator, if necessary, are sequentially supplied individually to the mixer or kneader, or two components ( A) (B) or a mixture of three components (A), (B), and (C) may be simultaneously performed by supplying them to the mixer or kneader. The melt mixing or melt kneading process may be performed in the presence of an antioxidant.
[0059]
When (A) polyacetal and (C) radical generator are melt-mixed or melt-kneaded in the absence of the polymerizable compound (B), the polyacetal is significantly reduced in molecular weight by the radical generator. On the other hand, when (A) polyacetal and (C) radical generator are melt-mixed or melt-kneaded in the presence of the polymerizable compound (B), it can be modified by the polymerizable compound and the amount of radical generator However, the polyacetal can be prevented from excessively reducing the molecular weight. Therefore, when (B) a polymerizable compound having a functional group is added to a molten mixture of (A) polyacetal and (C) radical generator and mixed in a molten state of polyacetal, A low molecular weight modified polyacetal can be obtained. Such a modified polyacetal can be used as a compatibilizing agent, an adhesion improving agent with a resin, a metal, an adhesive, a paint, or the like.
[0060]
In order to effectively utilize the radical generator for modification and to improve the modification efficiency by the polymerizable compound while suppressing decomposition of the polyacetal, (A) a polyacetal, (B) a polymerizable compound having a functional group, and (C) Mixing or kneading the three components with a radical generator in the molten state of polyacetal, or (C) in the presence of polyacetal and (B) polymerizable compound, (C) adding a radical generator to melt the polyacetal (C) a radical generator is added to a method of mixing or kneading in a state, (A) a mixture of polyacetal and (B) a polymerizable compound having a functional group, particularly a homogeneous mixture (preferably a compound or a molten mixture), A method of mixing or kneading in a molten state of polyacetal is useful. In such a method, the functional group of the polymerizable compound can be efficiently introduced while maintaining the high molecular weight and the excellent properties of the polyacetal. In particular, the above method has the advantage that the denaturation efficiency can be enhanced while suppressing the lowering of the molecular weight of the polyacetal (A) as compared with the first method.
[0061]
In such a method, for example, the three components and the compound are supplied to an apparatus such as the extruder, or a polyacetal and a polymerizable compound are melt-mixed in the apparatus, and then a radical generator is added or injected into the apparatus. It can be carried out by mixing or kneading. Further, a mixture of the compound and the radical generator may be supplied to the apparatus and mixed or kneaded. In many cases, the compound is used in the form of powder or pellets.
[0062]
Further, in order to increase the degree of modification by the polymerizable compound and the utilization efficiency of the radical generator, the melt mixing or melt kneading is preferably performed in the absence of a filler such as a reinforcing filler. That is, when melt mixing or melt kneading in the presence of a filler, it is often difficult to control the modification efficiency and melt viscosity of the polymerizable compound relative to polyacetal. On the other hand, when modified in the absence of a filler and a reinforcing agent, the radical generator and the polymerizable compound can be effectively used for modifying the polyacetal, and modified by a relatively large amount of filler and reinforcing agent. Therefore, a wide range of compositions can be obtained by combining the modified polyacetal and various thermoplastic resins.
[0063]
If necessary, a resin composition containing an additive, for example, a stabilizer such as an antioxidant, may be subjected to the above-described melt mixing or melt kneading operation. At that time, in order to increase the modification efficiency of the polyacetal by the polymerizable compound and the utilization efficiency of the radical generator, it is preferable that the amount of the additive is small. For example, for 100 parts by weight of the total amount of the polyacetal and the polymerizable compound 10 parts by weight or less, preferably 0.001 to 5 parts by weight, more preferably about 0.01 to 3 parts by weight.
[0064]
Of the additives, the addition of an antioxidant is useful for enhancing the stability of the modified polyacetal. Examples of the antioxidant include hindered phenols, hindered amines, and other compounds. Examples of hinted phenols include 2,6-di-t-butyl-p-cresol, 2,2'-methylenebis (4-methyl-6-t-butylphenol), 4,4'-methylenebis (2, 6-di-t-butylphenol), 4,4'-butylidenebis (3-methyl-6-t-butylphenol), 1,6-hexanediol-bis [3- (3,5-di-t-butyl-4) -Hydroxyphenyl) propionate], pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3- (3-t-butyl-5-methyl) -4-hydroxyphenyl) propionate], 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxyben Benzene, n-octadecyl-3- (4 ′, 5′-di-t-butylphenol) propionate, stearyl-β- (3,5-di-t-butyl-4-hydroxyphenol) propionate, distearyl- 3,5-di-tert-butyl-4-hydroxybenzylphosphonate, 2-tert-butyl-6- (3-tert-butyl-5-methyl-2-hydroxybenzyl-4-methylphenyl acrylate, N, N ′ Hexamethylene bis (3,5-di-t-butyl-4-hydroxy-hydrocinnamamide), 3,9-bis {2- [3- (3-t-butyl-4-hydroxy-5-methyl) Phenyl) propionyloxy] -1,1-dimethylethyl} -2,4,8,10-tetraoxaspiro [5,5] undecane, 4,4′-thiobis (3-methyl-6) -T-butylphenol), 1,1,3-tris (2-methyl-4-hydroxy-5-t-butylphenol) butane and the like.
[0065]
Examples of hindered amines include 4-acetoxy-2,2,6,6-tetramethylpiperidine, 4-stearoyloxy-2,2,6,6-tetramethylpiperidine, 4-acryloyloxy-2,2,6. , 6-tetramethylpiperidine, 4-methoxy-2,2,6,6-tetramethylpiperidine, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, 4-cyclohexyloxy-2,2,6 , 6-tetramethylpiperidine, 4-phenoxy-2,2,6,6-tetramethylpiperidine, 4-benzyloxy-2,2,6,6-tetramethylpiperidine, 4- (phenylcarbamoyloxy) -2, 2,6,6-tetramethylpiperidine, bis (2,2,6,6-tetramethyl-4-piperidyl) oxalate, bis (2, , 6,6-tetramethyl-4-piperidyl) malonate, bis (2,2,6,6-tetramethyl-4-piperidyl) adipate, bis (2,2,6,6-tetramethyl-4-piperidyl) Sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) adipate, bis (2,2,6, 6-tetramethyl-4-piperidyl) terephthalate, 1,2-bis (2,2,6,6-tetramethyl-4-piperidyloxy) ethane, bis (2,2,6,6-tetramethyl-4-) Piperidyl) hexamethylene-1,6-dicarbamate, tris (2,2,6,6-tetramethyl-4-piperidyl) benzene-1,3,5-tricarboxylate, phenyl-α-naphth Tylamine, phenyl-β-naphthylamine, N, N′-diphenyl-p-phenylenediamine, N-phenyl-N′-cyclohexyl-p-phenylenediamine, N-isopropyl-N′-phenyl-p-phenylenediamine, etc. It is done.
[0066]
Other antioxidants include, for example, sulfur-based antioxidants such as dimyristyl thiodipropionate, dilauryl thiodipropionate, distearyl thiodipropionate; triisodecyl phosphite, triphenyl phosphite, etc. Phosphorous antioxidants; hydroquinone antioxidants such as 2,5-di-t-butylhydroquinone and 2,5-diamilhydroquinone; 6-ethoxy-2,2,4-trimethyl-1,2-dihydro Quinoline antioxidants such as quinoline; mercaptohenzoimidazole and the like.
These antioxidants can be used alone or in combination of two or more. Preferred antioxidants include hindered phenols (phenolic antioxidants) and hindered amines (amine antioxidants).
[0067]
When polyacetal is modified in the presence of an antioxidant, the antioxidant may be added in (A) polyacetal or in the modification process. The usage-amount of antioxidant is 0.001-2 weight part with respect to 100 weight part of (A) polyacetal, Preferably it is about 0.01-1 weight part.
The modified polyacetal thus obtained may be pelletized as necessary.
[0068]
The modified polyacetal has high affinity and compatibility with not only the polyacetal (1) but also the core-shell polymer (2) depending on the type and amount of functional groups of the polymerizable compound. Therefore, even if polyacetal (1) and a core-shell polymer that is incompatible with this polyacetal are included, the properties of core-shell polymer (2) are effectively imparted to polyacetal (1), and particularly impact resistance and weld A resin composition having high strength and high weld elongation can be obtained.
[0069]
The ratio of the modified polyacetal (3) is, for example, the total amount of the polyacetal (1) and the core-shell polymer (2) / modified polyacetal (3) = 50/50 to 99/1 (weight ratio), preferably 70/30 to 99/1 (weight ratio), more preferably about 80/20 to 97/3 (weight ratio), and 70/30 to 90 / It is often about 10 (weight ratio).
[0070]
The polyacetal resin composition of the present invention is often produced in various ways, for example, by mixing the polyacetal (1), the core-shell polymer (2), and the modified polyacetal (3) in a molten state. . When mixing in a molten state, a conventional mixer or kneader, for example, an extruder, a brabender, a kneader, a Banbury mixer, a roll mixer, or the like can be used. Preferred melt mixing or kneaders include closed devices such as extruders and kneaders.
Depending on the type of the core-shell polymer (2), the mixing temperature is overlapped in the temperature range from the lower melting point (for example, the melting point) of the polyacetal (1) and the modified polyacetal (3) to the decomposition temperature. The temperature can be appropriately selected from a range of, for example, about 100 to 240 ° C, preferably about 130 to 230 ° C, more preferably about 160 to 220 ° C.
[0071]
In addition, (3) when the modified polyacetal is produced by melt mixing as described above, the polyacetal (1) and the core-shell polymer (2) are allowed to coexist in the melt mixture system of the polyacetal and the polymerizable compound, so that the polyacetal ( It is also possible to obtain the composition of the present invention composed of 1) a core-shell polymer (2) and a modified polyacetal (3).
[0072]
The modified polyacetal also exhibits high affinity, compatibility and wettability with respect to reinforcing agents and fillers depending on the type and amount of functional groups of the polymerizable compound. Therefore, in the present invention, a resin composition further containing a reinforcing agent or a filler is also preferable. Examples of the reinforcing agent include organic fibers (for example, polypropylene fibers, vinylon fibers, polyacrylonitrile fibers, polyamide fibers, aramid fibers, polyester fibers, etc.), inorganic fibers (glass fibers, alumina fibers, carbon fibers, metal fibers, etc.) , Whiskers (for example, whiskers such as alumina, beryllium oxide, boron carbide, silicon carbide, and silicon nitride). These reinforcing agents can be used alone or in combination.
Examples of the filler include alumina, silica, kaolin, clay, glass, zinc oxide, magnesium oxide, zirconium oxide, titanium oxide, aluminum hydroxide, calcium carbonate, magnesium carbonate, barium sulfate, potassium titanate, molybdenum disulfide, Examples thereof include carbon, graphite, and metal powder. These fillers can also be used singly or in combination.
The amount of the reinforcing agent and the filler used can be selected in accordance with the type of the reinforcing agent and the filler as long as the properties such as moldability are not impaired.
Furthermore, the resin composition may contain additives such as stabilizers such as antioxidants and ultraviolet absorbers, antistatic agents, lubricants, flame retardants, and colorants as necessary. The antioxidant may be added to the modified polyacetal.
The thermoplastic resin composition of the present invention is useful for obtaining various molded products by molding. The molded product can be obtained by a conventional method such as injection molding or extrusion molding.
[0073]
【The invention's effect】
The resin composition of the present invention is a polyacetal resin composition having high impact resistance and weld strength / elongation that can effectively impart the properties of the core-shell polymer to the polyacetal by mixing the core-shell polymer and the modified polyacetal with the polyacetal. Can be obtained.
In the method of the present invention, a resin composition having the above-mentioned high properties can be efficiently obtained by a simple operation of mixing a polyacetal, a core-shell polymer, and a modified polyacetal.
[0074]
【Example】
Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.
[Preparation of core-shell polymer]
Preparation Example 1 (Preparation of core-shell polymer A)
A polymerization vessel with a reflux condenser (capacity 5 liters) was charged with 320 g of deionized water and 66 g of a 10% by weight aqueous solution of polyoxyethylene nonylphenyl ether (manufactured by Kao Corporation, Emulgen 950) while stirring under a nitrogen stream. The temperature was raised to 70 ° C. After adding 77 g of the first stage monomer mixture having the following composition and dispersing for 10 minutes, 2,2-azobis (2-aminopropane) dihydrochloride (manufactured by Wako Pure Chemical Industries, Ltd., V-50) 2 154 g of a weight percent aqueous solution was added and polymerized to produce seed particles.
[Composition of first-stage monomer mixture]
n-Butyl acrylate 1533.84 g
Allyl methacrylate 3.08g
1,8-butylene glycol diacrylate 3.08 g
Next, an emulsion obtained by adding 440 g of a 10% by weight aqueous solution of polyoxyethylene nonylphenyl ether (manufactured by Kao Corporation, Emulgen 950) and 440 g of deionized water to the remaining 1463 g of the first-stage monomer mixture was continuously applied for 180 minutes. Fed and polymerized.
[0075]
After aging at a temperature of 70 ° C. for 1 hour, the second stage polymerization was started. That is, 66 g of a 2 wt% aqueous solution of 2,2-azobis (2-aminopropane) dihydrochloride (manufactured by Wako Pure Chemical Industries, Ltd., V-50) was added, and 1120 g of a second-stage monomer emulsion having the following composition: Was continuously fed over 60 minutes to perform seed polymerization.
[Composition of second stage monomer emulsion]
Methyl methacrylate 594.0g
Ethyl acrylate 66.0g
Polyoxyethylene nonylphenyl ether
(Emulgen 950) 220.0g
440.0 g of deionized water
After raising the reaction temperature to 80 ° C. and aging for 1 hour, the mixture was cooled and filtered through a 300 mesh stainless steel wire mesh to obtain a core-shell polymer latex. This latex was frozen at −15 ° C., filtered through a glass filter, and then air-dried overnight at 60 ° C. to obtain a core-shell polymer A.
[0076]
Preparation Examples 2 to 6 (core-shell polymers B to F)
Core-shell polymers B to F were obtained in the same manner as in Preparation Example 1 with the monomer composition shown in Table 1. For the core-shell polymer C, the obtained polymer was heated using a twin-screw extruder under reduced pressure at a cylinder temperature of 220 ° C. and a die head of 230 ° C., and an acid anhydride group was introduced by dehydration treatment of dicarboxylic acid. Was used to prepare a polyacetal resin composition described later.
[0077]
The meanings of the abbreviations of the monomers in Table 1 are as follows.
BA: n-butyl acrylate
AlMA: Allyl methacrylate
BGM: 1,4-butylene glycol diacrylate
MMA: Methyl methacrylate
EA: Ethyl acrylate
MAA: Methacrylic acid
IA: Itaconic acid
GMA: Glycidyl methacrylate
HEMA: 2-hydroxyethyl methacrylate
MAM: Methacrylamide.
[0078]
[Table 1]

[Preparation of modified polyacetal]
Preparation Example 7 (Preparation of modified polyacetal 1)
(A) 95 parts by weight of polyacetal [manufactured by Polyplastics Co., Ltd., trade name Duracon M25, polyacetal copolymer, melt flow rate 2.5 g / 10 min (190 ° C., 2.16 kg)] and (B) polymerizable compound [ N- [4- (2,3-epoxypropoxy) -3,5-dimethylbenzyl] acrylamide (manufactured by Kaneka Chemical Co., Ltd., trade name AX)] 5 parts by weight (5 parts per 100 parts by weight of polyacetal). 3 parts by weight) was dry blended and then melt kneaded at a temperature of 190 ° C. for about 2 minutes in a twin screw extruder to obtain pellets. 0.1 parts by weight of the obtained pellets and (C) radical generator [α, α'-bis (t-butylperoxy-m-isopropyl) benzene (Nippon Yushi Co., Ltd., trade name Perbutyl P)] Then, 0.11 part by weight with respect to 100 parts by weight of polyacetal was dry blended, and then melt-kneaded again at a temperature of 190 ° C. for about 2 minutes in a twin-screw extruder to obtain modified polyacetal pellets.
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The amount of modification by the polymerizable compound was 1.9% by weight. The amount of modification was measured as follows. In order to remove the polymerizable compound (B) that did not bind to the polyacetal, the modified polyacetal was purified by a reprecipitation method, and the polymerizable compound (B) introduced into the polyacetal was quantified by proton NMR. The amount of modification was expressed as a percentage by weight as a percentage of the polyacetal component. For reprecipitation, a solution of 150 mg of modified polyacetal and 4 ml of hexafluoroisopropanol was dropped into a reprecipitation solvent (acetone), and the precipitated polymer was collected by filtration. The modified polyacetal was purified by repeating this operation three times or more.
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Preparation Example 8 (Preparation of modified polyacetal 2)
In Preparation Example 7, a modified polyacetal was obtained in the same manner as Preparation Example 7, except that 5.3 parts by weight of the polymerizable compound [glycidyl methacrylate (Tokyo Chemical Industry Co., Ltd.)] was used with respect to 100 parts by weight of the polyacetal. The amount of modification by the active compound was 1.5% by weight, and chloroform was used as a reprecipitation solvent for purification by reprecipitation.
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Preparation Example 9 (Preparation of modified polyacetal 3)
In Preparation Example 7, a modified polyacetal was obtained in the same manner as Preparation Example 7, except that 5.3 parts by weight of the polymerizable compound [maleic anhydride (Tokyo Chemical Industry Co., Ltd.)] was used with respect to 100 parts by weight of the polyacetal. The amount of modification by the polymerizable compound was 2.0% by weight, and chloroform was used as a solvent for reprecipitation during purification by reprecipitation.
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Preparation Example 10 (Preparation of modified polyacetal 4)
In Preparation Example 7, 5.3 parts by weight of the polymerizable compound [2-vinyl-2-oxazoline (synthesized according to the method described in JP-A-63-10773)] is used with respect to 100 parts by weight of polyacetal. In the same manner as in Preparation Example 7, a modified polyacetal was obtained. The amount of modification by the polymerizable compound was 1.3% by weight. In the purification by reprecipitation, chloroform was used as a reprecipitation solvent.
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Preparation Example 11 (Preparation of modified polyacetal 5)
Polymerization is performed by adding 60 ppm of boron trifluoride to trioxane containing 3.3% by weight of 1,3-dioxolane, 0.8% by weight of allyl glycidyl ether and 100 ppm of methylal, and performing cationic polymerization. Polyacetal was prepared.
In Preparation Example 7, a modified polyacetal was obtained in the same manner as Preparation Example 7, except that the polymerizable polyacetal was used instead of the polyacetal. The amount modified by the polymerizable compound was 3.1% by weight.
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Examples 1 to 6 and Comparative Examples 1 and 2
After dry blending the modified polyacetals 1 to 5 obtained in the above preparation examples, core-shell polymers A and B, and polyacetal (manufactured by Polyplastics Co., Ltd., Duracon M90) in the proportions shown in Table 2, twin screw extrusion The mixture was melt kneaded at 190 ° C. in a machine and pelletized. This pellet was molded by an injection molding machine to produce an impact test piece and a weld test piece having gates at both ends. Izod impact strength was measured according to ASTM D256. Further, according to ASTM D638, the weld strength and weld elongation of the obtained test piece were measured. The results are shown in Table 2.
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[Table 2]

From Table 2, the impact resistance, weld strength, and elongation can be greatly improved by using the resin composition of the example containing the modified polyacetal as compared with the resin composition of the comparative example.
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Examples 7 to 11 and Comparative Examples 3 and 4
Test prepared in the same manner as in the above example using the modified polyacetal 1 obtained in the above preparation example, core-shell polymer B, and polyacetal (manufactured by Polyplastics Co., Ltd., Duracon M90) in the proportions shown in Table 3. When the Izod impact strength, weld strength and weld elongation of the piece were measured, the results shown in Table 3 were obtained.
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[Table 3]

From Table 3, compared with the resin composition of a comparative example, the resin composition of the Example containing a modified polyacetal has large impact strength, weld strength, and elongation.
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Examples 12-15 and Comparative Examples 5-8
Except for using the modified polyacetals 1, 3 and 5 obtained in the above preparation examples, core-shell polymers C to F, and polyacetal (manufactured by Polyplastics Co., Ltd., Duracon M90) in the proportions shown in Table 4, the above examples When the Izod impact strength, weld strength and weld elongation of the test piece prepared in the same manner as above were measured, the results shown in Table 4 were obtained.
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[Table 4]

From Table 4, compared with the resin composition of a comparative example, the resin composition of the Example containing a modified polyacetal has large impact strength, weld strength, and elongation.

Claims (13)

Polyacetal (1), a core of rubbery polymer carbon atoms in the alkyl group comprising an alkyl acrylate units is a 2 to 8, the core-shell polymer chromatography (2) having a glassy polymer shell, epoxy group, carboxyl group , Acid anhydride groups, ester groups, hydroxyl groups, ether groups, amide groups, amino groups, nitrile groups, isocyanate groups, imide groups, cycloalkyl groups, aryl groups, and heterocyclic groups having nitrogen atoms as heteroatoms A polyacetal resin composition comprising a modified polyacetal (3) in which a residue of a polymerizable compound having at least one functional group selected from the group is introduced into a polyacetal component.   The polyacetal resin composition according to claim 1, wherein the shell of the core-shell polymer (2) has at least one functional group selected from a carboxyl group, an acid anhydride group, an epoxy group, an amide group, and a hydroxyl group.   The polyacetal resin composition according to claim 1, wherein the core-shell polymer (2) is a core-shell polymer obtained by emulsion polymerization using a nonionic surfactant.   The polyacetal resin composition according to claim 1, wherein the modified polyacetal (3) is a modified polyacetal in which 0.1 to 30% by weight of a polymerizable compound residue is introduced with respect to the polyacetal component.   The polyacetal resin composition according to claim 1, wherein the modified polyacetal (3) is a modified polyacetal in which a residue of 0.2 to 25% by weight of a polymerizable compound is introduced with respect to the polyacetal component.   The polyacetal resin composition according to claim 1, wherein the polymerizable compound having a functional group has one ethylenically unsaturated bond per molecule.   A polymerizable compound having a functional group has one ethylenic double bond in one molecule and an epoxy group, a carboxyl group, an acid anhydride group, an ester group, a hydroxyl group, and a non-condensable functional group bonded to a nitrogen atom. N-substituted amide group, amino group, nitrile group, isocyanate group, imide group, cyclic imino ester group and at least one functional group selected from the group consisting of cyclic imino ether group, and having a boiling point at normal pressure The polyacetal resin composition according to claim 1, which is a compound having a temperature of 70 ° C or higher.   The polyacetal resin composition according to claim 1, wherein the polymerizable compound having a functional group is an ethylenic polymerizable compound having an epoxy group, a carboxyl group, an acid anhydride group, or an amide bond and an epoxy group. The polymerizable compound having a functional group is maleic anhydride or the following formula (1)

Wherein R ¹ is a hydrogen atom or a methyl group, and R ^{2 to} R ⁶ are the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an alkoxycarbonyl group, an acyl group, or an acyloxy group. Or 1)
The polyacetal resin composition of Claim 1 which is a compound represented by these.   The polyacetal resin composition according to claim 1, wherein the ratio of the polyacetal (1) and the core-shell polymer (2) is 60/40 to 99/1 in terms of weight ratio of polyacetal (1) / core-shell polymer (2). The ratio of the total amount of the polyacetal (1) and the core-shell polymer (2) to the modified polyacetal (3) is the total amount of the components (1) and (2) / modified polyacetal (3) = 50/50 to 99/1 (weight) the polyacetal resin composition of claim 1 wherein the ratio). At least one selected from polyacetal (1), a core of a rubber-like polymer containing an alkyl acrylate unit having 2 to 8 carbon atoms in the alkyl group , a carboxyl group, an acid anhydride group, an epoxy group, an amide group, and a hydroxyl group And a core-shell polymer (2) obtained by emulsion polymerization using a nonionic surfactant, and one ethylenically unsaturated bond in the molecule, And a modified polyacetal (3) modified with a polymerizable compound having a boiling point of 120 ° C. or higher, wherein the modified polyacetal (3) comprises an epoxy group, a carboxyl group, an acid anhydride group, an ester group, a hydroxyl group. Group, amide group having non-self-condensable functional group, amino group, nitrile group, isocyanate group, imide group, cyclic imino group A modified polyacetal in which a residue of a polymerizable compound having at least one functional group selected from the group consisting of a ter group and a cyclic imino ether group is introduced in an amount of 0.3 to 20% by weight based on the polyacetal component. The ratio of the total amount of the polyacetal (1) and the core-shell polymer (2) to the modified polyacetal (3) is the total amount of the components (1) and (2) / modified polyacetal (3) = 70/30 to 99/1 (weight). 2) The polyacetal resin composition according to claim 1. Polyacetal (1), a core of rubbery polymer carbon atoms in the alkyl group comprising an alkyl acrylate units is a 2 to 8, the core-shell polymer chromatography (2) having a glassy polymer shell, epoxy group, carboxyl group , Acid anhydride groups, ester groups, hydroxyl groups, ether groups, amide groups, amino groups, nitrile groups, isocyanate groups, imide groups, cycloalkyl groups, aryl groups, and heterocyclic groups having nitrogen atoms as heteroatoms A method for producing a polyacetal resin composition, wherein a residue of a polymerizable compound having at least one functional group selected from the group is mixed with a modified polyacetal (3) introduced into a polyacetal component.