JP2004091584A - Flame-retardant polybutylene terephthalate resin composition and molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a flame-retardant polybutylene terephthalate resin composition having high flame retardance, a short molding cycle, excellent productivity, no corrosion of electric contact points, especially high stability to hydrolysis and containing neither a bromine-based nor a chlorine-based flame retardant. <P>SOLUTION: The flame-retardant polybutylene terephthalate resin composition comprises a mixed resin composed of (A) 95-50 parts wt. of a polybutylene terephthalate which has ≤30 eq/t terminal carboxy group amount and ≥175°C crystallization temperature on cooling or ≥175°C crystallization temperature on cooling and ≤300 ppm residual tetrahydrofuran amount and (B) 5-50 parts wt. of a polyphenylene ether resin, (C) a compatibilizer, (D) a phosphoric acid ester or phosphonitrile, (F) a drip inhibitor and if necessary, (E) a reinforcing filler, (G) melamine cyanurate and (H) a metal borate. <P>COPYRIGHT: (C)2004,JPO

Description

【００２４】
（式中、Ｒ^１０は水素原子、第一級もしくは第二級アルキル基、アリール基、アミノアルキル基、炭化水素オキシ基を表し、Ｒ^１１は第一級あるいは第二級のアルキル基、アリール基、アルキルアミノ基を表す。ｒは１０以上の整数を表す。）。
Ｒ^１０で示される第一級アルキル基としては、例えば、メチル、エチル、ｎ−プロピル、ｎ−ブチル、ｎ−アミル、ｎ−ヘキシル、イソアミル、２−メチルブチル、２，３−ジメチルブチル、２，３−もしくは４−メチルペンチルまたはヘプチルが挙げられる。第二級アルキル基の好適な例としては、イソプロピル、ｓｅｃ−ブチル、、または１−エチルプロピルが挙げられる。好適なＰＰＥの単独重合体としては、例えば２，６−ジメチル−１，４−フェニレンエーテル単位からなるものである。好適な共重合体としては、上記単位と２，３，６−トリメチル−１，４−フェニレンエーテル単位の組合せからなるランダム共重合体である。
【００２５】
本発明で使用する成分（Ｂ）のＰＰＥは、クロロホルム中で測定した３０℃における固有粘度が、０．２〜０．８ｄｌ／ｇであるのが好ましく、より好ましくは固有粘度が０．２５〜０．７ｄｌ／ｇのものであり、特には０．３〜０．６ｄｌ／ｇのものが好適に使用される。固有粘度が０．２ｄｌ／ｇ未満では組成物の耐衝撃性が不充分となり、０．８ｄｌ／ｇを超えるとゲル成分が多く、成形品外観が悪化する傾向がある。
成分（Ｂ）ＰＰＥの量は、重量比で成分（Ａ）ポリブチレンテレフタレートに対する重量比率が、（Ａ）：（Ｂ）＝９５：５〜５０：５０であり、好ましくは９２：８〜５５：４５、特に好ましくは９０：１０〜６０：４０である。（Ｂ）の比率が５未満であると組成物の難燃性や耐加水分解性が不充分になり、５０より多いと組成物の流動性や耐薬品性が著しく低下する。
【００２６】
本発明の難燃性ポリエステル系樹脂組成物を製造するために用いられる成分（Ｃ）相溶化剤とは、ポリブチレンテレフタレート中におけるＰＰＥの分散性を向上させる化合物であり、ポリカーボネート樹脂やカルボキシル基、カルボン酸エステル基、酸アミド基、イミド基、酸無水物基、エポキシ基、オキサゾリニル基、アミノ基、水酸基から選ばれる官能基を一つ以上有する化合物や、亜リン酸エステル化合物等が使用できる。官能基を有する化合物の具体例としては、エポキシ基付加ＰＰＥ樹脂、ヒドロキシアルキル化ＰＰＥ樹脂、末端オキサゾリン化ＰＰＥ樹脂、ポリスチレンによりカルボキシル基末端が変性されたポリエステル、ポリエチレンによりＯＨ基末端が変性されたポリエステル等が挙げられる。（Ｃ）相溶化剤としては、本発明組成物の耐加水分解性、結晶性、機械的物性、難燃性の観点から、亜リン酸エステル又はポリカーボネート樹脂が好ましく、亜リン酸エステルにおいては亜リン酸トリエステルが好ましく、特に下記の一般式（３）、（４）で表される亜リン酸トリエステルが好適に用いられる。
【００２７】
【化４】

【００２８】
（式中、Ｒ^１２〜Ｒ^１４は、各々独立して、酸素原子、窒素原子、硫黄原子を含んでいても良い、炭素数１〜２０のアルキル基又は炭素数６〜３０の置換又は非置換アリール基を示す。）。
一般式（３）の具体例としては、トリオクチルホスファイト、トリデシルホスファイト、トリラウリルホスファイト、トリステアリルホスファイト、トリイソオクチルホスファイト、トリス（ノニルフェニル）ホスファイト、トリス（２，４−ジノニルフェニル）ホスファイト、トリス（２，４−ジ−ｔｅｒｔ−ブチルフェニル）ホスファイト、トリフェニルホスファイト、トリス（オクチルフェニル）ホスファイト、ジフェニルイソオクチルホスファイト、ジフェニルイソデシルホスファイト、オクチルジフェニルホスファイト、ジラウリルフェニルホスファイト、ジイソデシルフェニルホスファイト、ビス（ノニルフェニル）フェニルホスファイト、ジイソオクチルフェニルホスファイトなどが挙げられる。
【００２９】
【化５】

【００３０】
（式中、ｕは１または２であり、Ｒ^１５は、同じまたは異なって、酸素原子、窒素原子または硫黄原子を含んでいても良い、炭素数１〜２０のアルキル基又は炭素数６〜３０の置換又は非置換アリール基を示す。Ｒ^１６は、ｕが１の場合、炭素数１〜２０のアルキレン基又は炭素数６〜３０の置換又は非置換アリーレン基を示し、ｕが２の場合、炭素数４〜１８のアルキルテトライル基を示す。）。
Ｒ^１５の例としては、メチル、エチル、プロピル、オクチル、イソオクチル、イソデシル、デシル、ステアリル、ラウリル、フェニル、２，３−若しくは４−メチルフェニル、２，４−若しくは２，６−ジメチルフェニル、２，３，６−トリメチルフェニル、２−、３−若しくは４−エチルフェニル、２−，４−若しくは２−，６−ジエチルフェニル、２，３，６−トリエチルフェニル、２−，３−若しくは４−ｔｅｒｔ−ブチルフェニル、２，４−若しくは２，６−ジ−ｔｅｒｔ−ブチルフェニル、２，６−ジ−ｔｅｒｔ−ブチル−４−メチルフェニル、２，６−ジ−ｔｅｒｔ−ブチル−４−エチルフェニル、オクチルフェニル、イソオクチルフェニル、２−，３−若しくは４−ノニルフェニル、２，４−ジノニルフェニル、ビフェニル、ナフチル等が挙げられ、中でも置換又は非置換アリール基類が好ましい。
Ｒ^１６としては、一般式（４）で、ｕ＝１のとき、１，２−フェニレン基、エチレン、プロピレン、トリメチレン、テトラメチレン、ヘキサメチレン等のポリメチレン基が挙げられる。
【００３１】
一般式（４）の化合物の具体例としては、ｕが１の場合、例えば（フェニル）（１，３−プロパンジオール）ホスファイト、（４−メチルフェニル）（１，３−プロパンジオール）ホスファイト、（２，６−ジメチルフェニル）（１，３−プロパンジオール）ホスファイト、（４−ｔｅｒｔ−ブチルフェニル）（１，３−プロパンジオール）ホスファイト、（２，４−ジ−ｔｅｒｔ−ブチルフェニル）（１，３−プロパンジオール）ホスファイト、（２，６−ジ−ｔｅｒｔ−ブチルフェニル）（１，３−プロパンジオール）ホスファイト、（２，６−ジ−ｔｅｒｔ−ブチル−４−メチルフェニル）（１，３−プロパンジオール）ホスファイト、（フェニル）（１，２−エタンジオール）ホスファイト、（４−メチルフェニル）（１，２−エタンジオール）ホスファイト、（２，６−ジメチルフェニル）（１，２−エタンジオール）ホスファイト、（４−ｔｅｒｔ−ブチルフェニル）（１，２−エタンジオール）ホスファイト、（２，６−ジ−ｔｅｒｔ−ブチルフェニル）（１，２−エタンジオール）ホスファイト、（２，６−ジ−ｔｅｒｔ−ブチル−４−メチルフェニル）（１，２−エタンジオール）ホスファイト、（２，６−ジ−ｔｅｒｔ−ブチル−４−メチルフェニル）（１，４−ブタンジオール）ホスファイト等が挙げられる。
また、ｕ＝２のとき、Ｒ^１６は下記一般式（５）に示すペンタエリスリチル構造のテトライル基等が挙げられる。
【００３２】
【化６】

【００３３】
（式中、ｖ、ｗ、ｘ、ｙはそれぞれ０〜６の整数を示す。）。
具体例としては、ジイソデシルペンタエリスリトールジホスファイト、ジラウリルペンタエリスリトールジホスファイト、ジステアリルペンタエリスリトールジホスファイト、ジフェニルペンタエリスリトールジホスファイト、ビス（２−メチルフェニル）ペンタエリスリトールジホスファイト、ビス（３−メチルフェニル）ペンタエリスリトールジホスファイト、ビス（４−メチルフェニル）ペンタエリスリトールジホスファイト、ビス（２，４−ジメチルフェニル）ペンタエリスリトールジホスファイト、ビス（２，６−ジメチルフェニル）ペンタエリスリトールジホスファイト、ビス（２，３，６−トリメチルフェニル）ベンタエリスリトールジホスファイト、ビス（２−ｔｅｒｔ−ブチルフェニル）ペンタエリスリトールジホスファイト、ビス（３−ｔｅｒｔ−ブチルフェニル）ペンタエリスリトールジホスファイト、ビス（４−ｔｅｒｔ−ブチルフェニル）ペンタエリスリトールジホスファイト、ビス（２，４−ジ−ｔｅｒｔ−ブチルフェニル）ペンタエリスリトールジホスファイト、ビス（２，６−ジ−ｔｅｒｔ−ブチルフェニル）ペンタエリスリトールジホスファイト、ビス（２，６−ジ−ｔｅｒｔ−ブチル−４−メチルフェニル）ペンタエリスリトールジホスファイト、ビス（２，６−ジ−ｔｅｒｔ−ブチル−４−エチルフェニル）ペンタエリスリトールジホスファイト、ビス（ノニルフェニル）ペンタエリスリトールジホスファイト、ビス（ビフェニル）ペンタエリスリトールジホスファイト、ジナフチルペンタエリスリトールジホスファイト等が挙げられる。
【００３４】
これらの亜リン酸トリエステルの中では式（４）において、ｕが１又は２で示される化合物が好ましく、さらには式（４）のｕ＝２で、Ｒ^１６が一般式（５）に示すペンタエリスリチル構造のテトライル基等である化合物がより好ましい。その中でも、ビス（ノニルフェニル）ペンタエリスリトールジホスファイト、ビス（２，４−ジ−ｔｅｒｔ−ブチルフェニル）ペンタエリスリトールジホスファイト、ビス（２，６−ジ−ｔｅｒｔ−ブチル−４−メチルフェニル）ペンタエリスリトールジホスファイト等がより好ましく、特にはビス（２，４−ジ−ｔｅｒｔ−ブチルフェニル）ペンタエリスリトールジホスファイト、ビス（２，６−ジ−ｔｅｒｔ−ブチル−４−メチルフェニル）ペンタエリスリトールジホスファイト等が好適に使用される。
なお、本発明の組成物は、これら亜リン酸トリエステルの分解（加水分解や熱分解等）により生じた化合物を含んでいてもよい。
【００３５】
成分（Ｃ）相溶化剤として使用されるポリカーボネート樹脂としては、芳香族ジヒドロキシ化合物またはこれと少量のポリヒドロキシ化合物をホスゲンまたは炭酸のジエステルと反応させることによって製造される分岐していてもよい熱可塑性芳香族ポリカーボネート重合体または共重合体が挙げられる。
【００３６】
芳香族ジヒドロキシ化合物としては、２，２−ビス（４−ヒドロキシフェニル）プロパン（＝ビスフェノールＡ）、テトラメチルビスフェノールＡ、ビス（４−ヒドロキシフェニル）−ｐ−ジイソプロピルベンゼン、ハイドロキノン、レゾルシノール、４，４−ジヒドロキシジフェニルなどが挙げられ、好ましくはビスフェノールＡである。
【００３７】
分岐したポリカーボネート樹脂を得るには、フロログルシン、４，６−ジメチル−２，４，６−トリ（４−ヒドロキシフェニル）ヘプテン−２、４，６−ジメチル−２，４，６−トリ（４−ヒドロキシフェニル）ヘプタン、２，６−ジメチル−２，４，６−トリ（４−ヒドロキシフェニル）ヘプテン−３、１，３，５−トリス（４−ヒドロキシフェニル）ベンゼン、１，１，１−トリス（４−ヒドロキシフェニル）エタンなどで示されるポリヒドロキシ化合物、あるいは３，３−ビス（４−ヒドロキシアリール）オキシインドール（＝イサチンビスフェノール）、５−クロルイサチン、５，７−ジクロルイサチン、５−ブロムイサチンなどを前記芳香族ジヒドロキシ化合物の一部として用いればよく、使用量は、０．０１〜１０モル％であり、好ましくは０．１〜２モル％である。
【００３８】
ポリカーボネートの分子量を調節するには、一価芳香族ヒドロキシ化合物を用いればよく、ｍ−及びｐ−メチルフェノール、ｍ−及びｐ−プロピルフェノール、ｐ−ｔｅｒｔ−ブチルフェノール及びｐ−長鎖アルキル置換フェノールなどが挙げられる。
芳香族ポリカーボネート樹脂としては、好ましくは、２、２ービス（４ーヒドロキシフェニル）プロパンから誘導されるポリカーボネート樹脂、または２、２ービス（４ーヒドロキシフェニル）プロパンと他の芳香族ジヒドロキシ化合物とから誘導されるポリカーボネート共重合体が挙げられる。
本発明の（Ｃ）相溶化剤として使用されるポリカーボネート樹脂の分子量は、溶媒としてメチレンクロライドを用い、温度２５℃で測定された溶液粘度より換算した粘度平均分子量で、１６，０００〜３０，０００が好ましく、更に好ましくは１８，０００〜２３，０００である。ポリカーボネート樹脂としては、２種以上のポリカーボネート樹脂を混合して用いることもできる。
【００３９】
成分（Ｃ）相溶化剤の量は成分（Ａ）と（Ｂ）との合計１００重量部に対して０．０５〜１０重量部であり、好ましくは０．１〜８重量部、特に好ましくは０．３〜５重量部である。成分（Ｃ）相溶化剤の量が０．０５重量部より少ないと本発明の樹脂組成物の物性、特に機械的強度や難燃性が低下し、１０重量部より多いと難燃性、製品の表面外観が低下する。
【００４０】
本発明に使用される成分（Ｄ）リン酸エステル化合物としては、広範囲のリン酸エステルが包含され、具体例に、例えばトリメチルホスフェート、トリエチルホスフェート、トリブチルホスフェート、トリオクチルホスフェート、トリブトキシエチルホスフェート、トリフェニルホスフェート、トリクレジルホスフェート、クレジルジフェニルホスフェート、オクチルジフェニルホスフェート等が挙げられるが、中でも下記一般式（１）で表される化合物が好ましい。
【００４１】
【化７】

【００４２】
（式中、Ｒ^１〜Ｒ^８は、それぞれ独立して、水素原子または炭素数１〜６のアルキル基を示し、ｍは０または１〜４の整数である。Ｒ^９は，ｐ−フェニレン基、ｍ−フェニレン基、４，４’−ビフェニレン基または以下から選ばれる２価の基である。）。
【００４３】
【化８】

【００４４】
一般式（１）において、Ｒ^１〜Ｒ^８は、本発明組成物の耐加水分解性を向上させるためには、炭素数６以下のアルキル基が好ましく、中でも炭素数２以下のアルキル基、特にメチル基が好ましい。ｍは好ましくは１〜３、中でも１が好ましい。Ｒ^９は、中でもｐ−フェニレン基、ｍ−フェニレン基が好ましく、特にｍ−フェニレン基が好適である。
また成分（Ｄ）としては下記一般式（６）で表される基を有するホスホニトリル化合物も好適に用いられる。
【００４５】
【化９】

【００４６】
（式中、Ｘは−Ｏ−、−Ｓ−、−ＮＨ−または直接結合を表す。Ｒ^１７及びＲ^１８は炭素数１〜２０のアリール基、アルキル基、シクロアルキル基を示す。Ｒ^１７−Ｘ−，Ｒ^１８−Ｘ−は同一でも異なっていても良い。ｎは１〜１２の整数を示す。）。
一般式（６）において、Ｒ^１７，Ｒ^１８の具体例としては、メチル、エチル、ブチル、ヘキシル、ベンジル等の置換されていても良いアルキル基、シクロヘキシル等のシクロアルキル基、フェニル、ナフチル等のアリール基が挙げられる。ｎは好ましくは３〜１０であり、特に３または４が好ましい。一般式（６）のホスホニトリル化合物は線状重合体であっても環状重合体であっても構わないが、中でも環状重合体が好適に用いられる。Ｘは−Ｏ−、−ＮＨ−が好ましく、特に−Ｏ−が好ましい。
一般式（６）で示されるホスホニトリル化合物の具体例としては例えば、ヘキサフェノキシシクロトリホスファゼン、ヘキサ（ヒドロキシフェノキシ）シクロトリホスファゼン、オクタフェノキシシクロテトラホスファゼン、オクタ（ヒドロキシフェノキシ）シクロテトラホスファゼンなどが挙げられる。
【００４７】
成分（Ｄ）の量は（Ａ）と（Ｂ）との合計１００重量部に対して２〜４５重量部であり、好ましくは３〜４０重量部、特には５〜３０重量部が好ましい。（Ｄ）の量が２重量部より少ないと組成物の難燃性が不充分になり、４５重量部より多いと機械的物性、耐加水分解性、成形性が著しく低下する。
【００４８】
本発明組成物は、（Ｅ）強化充填材を含有することが好ましい。用いられる（Ｅ）強化充填材の種類は特に制限はなく、樹脂の強化に使用される種々の充填材が用いられる。具体的には、例えば、ガラス繊維、カーボン繊維、シリカ・アルミナ繊維、ジルコニア繊維、ホウ素繊維、窒化ホウ素繊維、窒化ケイ素チタン酸カリウム繊維、金属繊維などの無機繊維、芳香族ポリアミド繊維、フッ素樹脂繊維などの有機繊維などを挙げることができる。これらの強化充填材は、１種を単独で用いることができ、あるいは、２種以上を組み合わせて用いることもできる。これらの中で、無機充填材を好適に用いることができ、ガラス繊維を特に好適に用いることができる。強化充填材が無機繊維又は有機繊維である場合、その平均繊維径に特に制限はないが、１〜１００μｍであることが好ましく、２〜５０μｍであることがより好ましく、３〜３０μｍであることがさらに好ましく、５〜２０μｍであることが特に好ましい。また、平均繊維長にも特に制限はないが、０．１〜２０ｍｍであることが好ましく、１〜１０ｍｍであることがより好ましい。強化充填材は、ポリブチレンテレフタレートとの界面密着性を向上させるために、収束剤又は表面処理剤で表面処理して用いることが好ましい。収束剤又は表面処理剤としては、例えば、エポキシ系化合物、アクリル系化合物、イソシアネート系化合物、シラン系化合物、チタネート系化合物などの官能性化合物を挙げることができる。（Ｅ）強化充填材は、収束剤又は表面処理剤によりあらかじめ表面処理しておくことができ、あるいは、本発明のポリブチレンテレフタレート樹脂組成物の調製の際に、（Ｅ）強化充填材と共に収束剤又は表面処理剤を添加して表面処理することもできる。強化充填材の量は、（Ａ）ポリブチレンテレフタレート及び（Ｂ）ＰＰＥの合計１００重量部に対して、０〜１５０重量部であり、好ましくは５〜１００重量部である。
【００４９】
本発明の難燃性ポリブチレンテレフタレート樹脂組成物には、（Ｅ）強化充填材とともに他の充填材を配合することができる。配合する他の充填材としては、例えば、板状無機充填材、セラミックビーズ、アスベスト、ワラストナイト、タルク、クレー、マイカ、ゼオライト、カオリン、チタン酸カリウム、硫酸バリウム、酸化チタン、酸化ケイ素、酸化アルミニウム、水酸化マグネシウムなどを挙げることができる。板状無機充填材を配合することにより、成形品の異方性及びソリを低減することができる。板状無機充填材としては、例えば、ガラスフレーク、雲母、金属箔どを挙げることができる。これらの中で、ガラスフレークを特に好適に用いることができる。
【００５０】
本発明に使用される（Ｆ）滴下防止剤とは、燃焼時の樹脂の滴下を防止する性質を有する化合物を指し、具体的な例としては、シリコンオイル、シリカ、アスベスト、フッ素樹脂やタルク、マイカなどの層状珪酸塩等が挙げられる。中でも組成物の難燃性の観点から好ましい滴下防止剤として、フッ素含有ポリマー、層状珪酸塩等が挙げられる。
【００５１】
成分（Ｆ）滴下防止剤の量は、成分（Ａ）と（Ｂ）との合計１００重量部に対して０．００１〜１５重量部の範囲から選ばれる。滴下防止剤の量が少ないと、燃焼中の滴下防止効果が不十分であり、多すぎると、流動性や機械的物性の低下を招く畏れがある。
【００５２】
（Ｆ）滴下防止剤として使用されるフッ素樹脂としては、ポリテトラフルオロエチレン、テトラフルオロエチレン／パーフルオロアルキルビニルエーテル共重合体、テトラフルオロエチレン／ヘキサフルオロプロピレン共重合体、テトラフルオロエチレン／エチレン共重合体、フッ化ビニリデン、ポリクロロトリフルオロエチレン等のフッ素化ポリオレフィンが好ましく、中でもポリテトラフルオロエチレン、テトラフルオロエチレン／パーフルオロアルキルビニルエーテル共重合体、テトラフルオロエチレン／ヘキサフルオロプロピレン共重合体、テトラフルオロエチレン／エチレン共重合体がより好ましく、特にはポリテトラフルオロエチレン、テトラフルオロエチレン／ヘキサフルオロプロピレン共重合体が好適に用いられる。
【００５３】
（Ｆ）滴下防止剤として使用されるフッ素樹脂は、３５０℃における溶融粘度が、１．０×１０^２〜１．０×１０^１５（Ｐａ・ｓ）のものが好ましく、中でも１．０×１０^３〜１．０×１０^１４（Ｐａ・ｓ）、特には１．０×１０^１０〜１．０×１０^１２（Ｐａ・ｓ）のものが好適に用いられる。溶融粘度が１．０×１０^２（Ｐａ・ｓ）未満であると燃焼時の滴下防止能が不充分であり、１．０×１０^１５（Ｐａ・ｓ）より大きくなると組成物の流動性が著しく低下するので好ましくない。
【００５４】
フッ素樹脂の量は、成分（Ａ）と（Ｂ）との合計１００重量部に対して０．００１〜１５重量部であり、好ましくは０．００５〜１２重量部、特には０．０１〜１０重量部が好ましい。フッ素樹脂の添加量が０．００１重量部より少ないと燃焼中の滴下防止効果が不充分であり、１５重量部より多いと流動性や機械的物性が低下する。
【００５５】
成分（Ｆ）滴下防止剤として層状珪酸塩を使用することは、本発明樹脂組成物の溶融時の流動性の観点からは好ましい。層状珪酸塩としては、層状珪酸塩、変性層状珪酸塩（層間に４級有機オニウムカチオンを挿入した層状珪酸塩）、反応性官能基を付与した層状珪酸塩または変性層状珪酸塩が挙げられるが、層状珪酸塩の本発明樹脂組成物への分散性および滴下防止能の観点から、変性層状珪酸塩、反応性官能基を付加した層状珪酸塩または変性層状珪酸塩が好ましく、特にはエポキシ基、アミノ基、オキサゾリン基、カルボキシル基、酸無水物等の反応性官能基を付加した層状珪酸塩または変性層状珪酸塩が好適に用いられる。官能基付与方法としては特に制限はないが、官能化試薬（シランカップリング剤）で処理する方法が簡単で好ましい。
【００５６】
官能化試薬として具体的には、例えは、エポキシ基を有するクロロシラン類、カルボキシル基を有するクロロシラン類、メルカプト基を有するクロロシラン類、アミノ基を有するアルコキシシラン類、エポキシ基を有するアルコキシシラン類等が挙げられるが、中でも３−グリシジルオキシプロピルジメチルクロロシラン、β−（３，４−エポキシシクロヘキシル）エチルジメチルクロロシラン、３−グリシジルオキシプロピルトリクロロシラン等のエポキシ基を有するクロロシラン類、３−アミノプロピルトリエトキシシラン、Ｎ−（２−アミノエチル）−３−アミノプロピルトリメトキシシラン、Ｎ−（２−アミノエチル）−３−アミノプロピルメチルジメトキシシラン等のアミノ基を有するアルコキシシラン類、３−グリシジルオキシプロピルメチルジエトキシシラン、３−グリシジルオキシプロピルトリメトキシシラン、β−（３，４−エポキシシクロヘキシル）エチルトリメトキシシラン等のエポキシ基を有するアルコキシシラン類が好ましい。これら官能化試薬の層状珪酸塩への接触方法は特に制限はないが、通常無溶媒または極性溶媒中での混合により行なうことが好ましい。
【００５７】
本発明に用いられる層状珪酸塩の具体例としては、モンモリロナイト、ヘクトライト、フッ素ヘクトライト、サポナイト、バイデライト、スブチンサイト等のスメクタイト系粘土鉱物、Ｌｉ型フッ素テニオライト、Ｎａ型フッ素テニオライト、Ｎａ型四珪素フッ素雲母、Ｌｉ型四珪素フッ素雲母等の膨潤性合成雲母、バーミキュライト、フッ素バーミキュライト、ハロイサイト等が挙げられ、天然のものであっても合成されたものであってもよい。中でも、モンモリロナイト、ヘクトライト等のスメクタイト系粘土鉱物、Ｌｉ型フッ素テニオライト、Ｎａ型フッ素テニオライト、Ｎａ型四珪素フッ素雲母等の膨潤性合成雲母が好ましい。
【００５８】
本発明に用いられる変性層状珪酸塩の層間に挿入される４級オニウムカチオンに特に制限はないが、好適に使用される具体例としては、トリメチルオクチルアンモニウム、トリメチルデシルアンモニウム、トリメチルドデシルアンモニウム、トリメチルテトラデシルアンモニウム、トリメチルヘキサデシルアンモニウム、トリメチルオクタデシルアンモニウム等のトリメチルアルキルアンモニウム、ジメチルジオクチルアンモニウム、ジメチルジデシルアンモニウム、ジメチルジドデシルアンモニウム、ジメチルジテトラアンモニウム、ジメチルジヘキサデシルアンモニウム、ジメチルジオクタデシルアンモニウム等のジメチルジアルキルアンモニウムなどが挙げられる。
【００５９】
本発明のポリエステル樹脂組成物における成分（Ｆ）として層状珪酸塩を用いる場合その添加量は成分（Ａ）と（Ｂ）との合計１００重量部に対して０．１〜１５重量部であり、好ましくは０．３〜１２重量部、特に好ましくは０．５〜１０重量部である。成分（Ｆ）としての層状珪酸塩が０．１重量部より少ないと燃焼中の滴下防止効果が不充分であり、１５重量部より多いと流動性や機械的物性が極端に低下する。尚、層状珪酸塩は１種類を用いてもよく、或いは２種以上を併用してもよい。
【００６０】
成分（Ｆ）滴下防止剤としては、シリコンオイルを用いることも好ましく、シリコンオイルとしては下記一般式（７）で表されるジメチルポリシロキサン骨格を有する化合物であり、末端または側鎖の一部あるいは全部がアミノ変性、エポキシ変性、カルボキシル変性、カルビノール変性、メタクリル変性、メルカプト変性、フェノール変性、ポリエーテル変性、メチルスチリル変性、アルキル変性、高級脂肪酸エステル変性、高級アルコキシ変性、フッ素変性を受け官能基化されていてもよい。
【００６１】
【化１０】

【００６２】
（Ｆ）滴下防止剤として使用するシリコンオイルの粘度は、２５℃において、１０００〜３００００（ｃｓ．）が好ましく、中でも２０００〜２５０００（ｃｓ．）、特には３０００〜２００００（ｃｓ．）が好ましい。１０００（ｃｓ．）未満であると燃焼中の滴下防止作用が充分でなくなり難燃性が大きく低下し、３００００（ｃｓ．）より大きいと、増粘効果により組成物の流動性が著しく低下する。成分（Ｆ）滴下防止剤として、シリコンオイルを使用する場合の量は、成分（Ａ）と（Ｂ）との合計１００重量部に対して０．００１〜１０重量部であり、好ましくは０．００５〜８重量部、特に好ましくは０．０１〜５．０重量部である。成分（Ｆ）としてのシリコンオイルが０．００１重量部未満であると滴下防止効果が不充分であり、１０重量部より多いと流動性、機械的性質が著しく低下する。
【００６３】
本発明組成物は、（Ｇ）シアヌル酸メラミンを含有することが好ましい。（Ｇ）シアヌル酸メラミンとはシアヌル酸とメラミンのほぼ等モル反応物であって、例えばシアヌル酸の水溶液とメラミンの水溶液とを混合し、９０〜１００℃の温度で攪拌下反応させ、生成した沈澱を濾過することにより得ることができる。該シアヌル酸メラミンの粒径は０．０１〜１０００ミクロン、好ましくは０．０１〜５００ミクロンである。シアヌル酸メラミンのアミノ基または水酸基のいくつかが、他の置換基で置換されていても良い。シアヌル酸メラミンの量は成分（Ａ）と（Ｂ）の合計１００重量部に対して０〜４５重量部であり、好ましくは３〜４０重量部、特に好ましくは５〜３０重量部である。シアヌル酸メラミンの添加量が、４５重量部より多いと靱性や延性を低下させたり、ブリードアウトやプレートアウトを引き起こしたりする。
成分（Ｄ）と成分（Ｇ）シアヌル酸メラミンの比率は、特に限定されるものではないが、通常１対９〜９対１、中でも２対８〜８対２、特に好ましくは２．５対７．５〜７．５対２．５である。
【００６４】
本発明のポリエステル樹脂組成物は（Ｈ）硼酸金属塩を含有することが好ましい。本発明に用いられる成分（Ｈ）硼酸金属塩とは、通常用いる処理条件下で安定であり、揮発成分のないものが好ましい。（Ｈ）硼酸金属塩としては硼酸のアルカリ金属塩（例えば四硼酸ナトリウム、メタ硼酸カリウム等）あるいはアルカリ土類金属塩（例えば硼酸カルシウム、オルト硼酸マグネシウム、オルト硼酸バリウム、硼酸亜鉛等）等が挙げられる。これらの中でも好ましくは、硼酸亜鉛である。硼酸亜鉛は、一般に、２ＺｎＯ・３Ｂ_２Ｏ_３・ｘＨ_２Ｏ（ｘ＝３．３〜３．７）で示される。水和硼酸亜鉛としては好ましくは、２ＺｎＯ・３Ｂ_２Ｏ_３・３．５Ｈ_２Ｏの式をもつものであり、かつ２６０℃又はそれより高い温度まで安定なものである。
硼酸金属塩の量は、成分（Ａ）と（Ｂ）の合計１００重量部に対して０〜５０重量部であり、好ましくは２〜４５重量部、特に好ましくは３〜４０重量部である。（Ｈ）硼酸金属塩の配合量が５０重量部を越えると機械的物性が低下しやすい。
【００６５】
本発明のポリブチレンテレフタレート樹脂組成物には、必要に応じて、上記（Ａ）〜（Ｈ）の成分の他に、慣用の添加剤などを配合することができる。配合する添加剤に特に制限はなく、例えば、酸化防止剤、耐熱安定剤などの安定剤、滑剤、離型剤、触媒失活剤、結晶核剤、結晶化促進剤などの添加剤は、ポリブチレンテレフタレート重合途中あるいは重合後に添加することができる。また、耐加水分解性をさらに向上させるべくエポキシ化合物、カルボジイミド、オキサゾリン等を添加できる。さらに、ポリブチレンテレフタレートに、所望の性能を付与するために、紫外線吸収剤、耐候安定剤などの安定剤、染顔料などの着色剤、帯電防止剤、発泡剤、可塑剤、耐衝撃性改良剤などを配合することができる。
本発明のポリブチレンテレフタレート樹脂組成物には、必要に応じて、ポリエチレン、ポリプロピレン、アクリル樹脂、ポリカーボネート、ポリアミド、ポリフェニレンサルファイド樹脂、ポリエチレンテレフタレート、液晶ポリエステル樹脂、ポリアセタール、ポリフェニレンオキサイドなどの熱可塑性樹脂や、エポキシ樹脂、フェノール樹脂、メラミン樹脂、シリコーン樹脂などの熱硬化性樹脂を配合して成形品とすることができる。これらの熱可塑性樹脂及び熱硬化性樹脂は、１種を単独で用いることができ、あるいは、２種以上を組み合わせて用いることもできる。
【００６６】
本発明の難燃性ポリエステル樹脂組成物の製造法は特に限定されるものではなく、公知の方法により各成分を混合することにより容易に達成することができる。例えば、ブレンダーやミキサーなどを使用してドライブレンドする方法、押出機を使用して溶融混合する方法などが挙げられるが、通常スクリュー押出機を使用して溶融混合してストランドの押し出し、ペレット化する方法が適している。具体的には、各成分を一括して溶融混練する方法、特定成分を先に溶融混合する方法等が挙げられるが、中でも機械的物性の観点から、成分（Ａ）ポリエステル樹脂と成分（Ｂ）ＰＰＥと成分（Ｃ）相溶化剤の３成分を先に溶融混合した後に、残りの成分を混合する製造方法が好ましく、特には、成分（Ａ）と成分（Ｂ）と成分（Ｃ）と（Ｂ）可溶媒の４成分を先に溶融混合した後に、残りの成分を混合する製造方法が好ましい。溶媒としては、キシレン、トルエン、トリクロロベンゼン、クロロホルム、α−クロロナフタレン等が挙げられるが、腐食性ガス発生の抑制、脱溶媒の容易性の観点から、キシレン、トルエンが好ましく、特にキシレンが好適に用いられる。
【００６７】
各成分の混合方法は、特に制限されることはなく、二軸スクリュー押出機を用いて成分を一括して溶融混練する一括ブレンド方法、および強化充填材等を他の供給口から添加する分割ブレンド方法などが挙げられる。
【００６８】
本発明のポリブチレンテレフタレート成形品の成形加工方法に特に制限はなく、熱可塑性樹脂について一般に用いられている成形法、すなわち、射出成形、中空成形、押し出し成形、プレス成形などの成形法を適用することができる。
【００６９】
本発明の難燃性ポリブチレンテレフタレート樹脂組成物は難燃性、機械的物性、耐加水分解性等に優れ、腐食性ガス発生による金型腐食がなく、さらに低比重、流動性に優れることから薄肉あるいは複雑な形状の成形品用途に好適に使用することができる。従って、本発明組成物は電気機器、電子機器あるいはそれ等の部品を製造する材料として好適である。
【００７０】
【実施例】
以下に、本発明を実施例により更に詳しく説明するが、本発明はその要旨を越えない限りこれらの実施例に限定されるものではない。
なお、実施例及び比較例において、ポリブチレンテレフタレートの物性の測定及び本発明樹脂組成物の評価は下記の方法により行った。
（１）末端カルボキシル基量；
ポリブチレンテレフタレート０．１ｇをベンジルアルコール３ｍｌに溶解し、水酸化ナトリウムの０．１モル／リットル−ベンジルアルコール溶液を用いて滴定した。
【００７１】
（２）降温結晶化温度；
示差走査熱量計［パーキンエルマー社、型式１Ｂ］を用い、ポリブチレンテレフタレートを、昇温速度２０℃／分で室温から３００℃まで昇温したのち、降温速度２０℃／分で８０℃まで降温した場合の、発熱ピークの温度を測定し、降温結晶化温度とした。
【００７２】
（３）残存テトラヒドロフラン量；
ポリブチレンテレフタレートのペレット５ｇを水１０ｇに浸漬し、加圧下に１２０℃で６時間処理し、水中に溶出したテトラヒドロフランをガスクロマトグラフィーにより定量した。
【００７３】
（４）固有粘度；
ウベローデ型粘度計とフェノール／１，１，２，２−テトラクロロエタン（重量比１／１）の混合溶媒を用い、３０℃において、濃度１．０ｇ／ｄｌ、０．６ｇ／ｄｌ及び０．３ｇ／ｄｌ溶液の粘度を測定し、粘度数を濃度０に外挿した。
【００７４】
（５）難燃性；
実施例で製造した試験片につき、アンダーライターズラボラトリーズィンコーポレーションのＵＬ−９４「材料分類のための燃焼試験」（以下、ＵＬ−９４）に示される試験方法に従って試験し、厚さが１／３２インチの５本の試験片の結果に基づいてＵＬ−９４規格のＶ−０、Ｖ−１およびＶ−２のいずれかの等級に評価した。ＵＬ−９４についての各Ｖの等級基準は、概略以下のとおりである。（ｉ）Ｖ−０：点火炎を取り除いた後の平均火炎保持時間が５秒以下であり、かつ、全試験片とも脱脂綿に着火するような微粒炎を落下しない。
（ｉｉ）Ｖ−１：点火炎を取り除いた後の平均火炎保持時間が２５秒以下であり、かつ、全試験片とも脱脂綿に着火するような微粒炎を落下しない。
（ｉｉｉ）Ｖ−２：点火炎を取り除いた後の平均火炎保持時間が２５秒以下であり、かつ、これらの試験片から落下した微粒炎から脱脂綿に着火する。
【００７５】
（６）発生ガス；
樹脂組成物ペレット５ｇを内容量２６ｍｌのガラス製バイヤル瓶に入れ、１５０℃で２時間加熱した後、気相部からマイクロシリンジを用いてサンプルを採取し、ガスクロマトグラフィーにより分析する。クロマトグラムのピーク面積を求め、その面積に相当する量のテトラヒドロフラン重量を樹脂に対する比（ｐｐｍ）として表した。
【００７６】
（７）耐加水分解性；
ＡＳＴＭ１号ダンベル片を、１２１℃、飽和水蒸気中、２０３ｋＰａで、非強化の場合は６０時間、ガラス繊維（ＧＦ）強化の場合は１００時間それぞれ湿熱処理する。処理前後の引張強度を、ＡＳＴＭ　Ｄ−６３８に従って測定し、次式に従い、強度保持率を求めた。なお、次式における湿熱処理後の引張強度は、非強化では６０時間処理後の値、ＧＦ強化では１００時間処理後の値である。
【００７７】
【数１】
強度保持率（％）＝（湿熱処理後の引張強度／処理前の引張強度）×１００
【００７８】
実施例及び比較例で使用したポリブチレンテレフタレート以外の各成分は下記の通りである。
（ａ）ＰＰＥ：ポリフェニレンエーテル（三菱エンジニアリングプラスチック（株）製、商品名ユピエース、固有粘度０．３６）。
（ｂ）ＰＣ：ポリカーボネート（三菱エンジニアリングプラスチック（株）製、商品名ノバレックス、固有粘度０．３６）。
（ｃ）リン酸エステル：下式（８）で示されるリン酸エステル。
【００７９】
【化１１】

【００８０】
（ｄ）シアヌル酸メラミン：三菱化学（株）製。
（ｅ）ＧＦ：ガラス繊維（日本電気硝子（株）製、エポキシシラン処理品、３ｍｍチョップドストランド　銘柄名：Ｔ−１８７）。
（ｆ）ＰＴＦＥ：ポリテトラフルオロエチレン（ダイキン工業（株）製、四フッ化エチレン樹脂、ポリフロンＦ２０１）。
（ｇ）硼酸亜鉛：ボラックス・ジャパン（株）製。
【００８１】
実施例１
図１に示す系統図に従って連続重合を行った。テレフタル酸１．０モルに対して１，４−ブタンジオール１．８モルの割合で両原料をスラリー調製槽に供給し、攪拌装置で混合して調製したスラリー２，９７２重量部（テレフタル酸９．０６モル部、１，４−ブタンジオール１６．３１モル部）を、連続的にギヤポンプにより、温度２３０℃、圧力１０１ｋＰａに調整し、第一エステル化反応槽に移送するとともに、テトラブチルチタネート３．１４重量部を供給し、滞留時間２時間で、攪拌下にエステル化反応させてオリゴマーを得た。
第一エステル化反応槽から、オリゴマーを、温度２４０℃、圧力１０１ｋＰａに調整した第二エステル化反応槽に移送し、滞留時間１時間で、撹拌下にエステル化反応をさらに進めた。
第二エステル化反応槽から、オリゴマーを、温度２５０℃、圧力６．６７ｋＰａに調整した第一重縮合反応槽に移送し、滞留時間２時間で、攪拌下に重縮合反応させ、プレポリマーを得た。
第一重縮合反応槽から、プレポリマーを、温度２５０℃、圧力１３３Ｐａに調整した第二重縮合反応槽に移送し、滞留時間３時間で、攪拌下に重縮合反応をさらに進めて、ポリマーを得た。このポリマーを第二重縮合槽から抜き出してダイに移送し、ストランド状に引き出して、ペレタイザーで切断することにより、ベレット状のポリブチレンテレフタレートを得た。
【００８２】
得られたポリブチレンテレフタレートの末端カルボキシル基量は２０ｅｑ／ｔであり、降温結晶化温度は１７８℃、残存テトラヒドロフラン量は１８０ｐｐｍ（重量比）、固有粘度は０．８５ｄｌ／ｇであった。
このポリブチレンテレフタレート７０重量部、ＰＰＥ３０重量部、ＰＣ２重量部、リン酸エステル化合物１５重量部、シアヌル酸メラミン１５重量部、硼酸亜鉛４重量部、ＧＦ５９重量部、ポリテトラフルオロエチレン１重量部をブレンドし、これを３０ｍｍのベントタイプ二軸押出機（日本製鋼所（株）製、二軸押出機ラボＴＥＸ３０）を使用してバレル温度２７０℃において溶融混練してストランドに押し出した後、ストランドカッターによりペレット化した。得られたペレットを用い、試験片を成形した。ＵＬ−９４燃焼試験片は、射出成形機（日本製鋼所（株）製、型式Ｊ２８ＳＡ）と、ＵＬ−９４燃焼試験片用の金型を使用し、シリンダー温度２７０℃、金型温度８０℃で、ＡＳＴＭ１号ダンベル片は、射出成形機（住友重機（株）製、型式ＳＧ−７５）により、シリンダー温度２５５℃、金型温度８０℃で、それぞれ成形を行い評価した。
湿熱処理前の引張強度は１２５ＭＰａ湿熱処理後の引張強度は６９ＭＰａであり、強度保持率は５５％であった。また、難燃性はＶ−０で、発生ガス量は１６ｐｐｍであった。結果を表−１に示した。
【００８３】
実施例２、３及び比較例１、２
表−１に示した処方により樹脂組成物を製造し、実施例１と同様にして評価した。結果を表−１に示した。
【００８４】
比較例３
回分式装置を用いて、重合反応を行った。テレフタル酸ジメチル１．０モルに対して、１，４−ブタンジオール１．８モルの割合で、合計３，２２６重量部をエステル交換反応槽に供給し、テトラブチルチタネート３．１４重量部を添加し、温度２１０℃、圧力１０１ｋＰａで、３時間エステル交換反応させて、オリゴマーを得た。引き続いて、このオリゴマーを、重縮合反応槽に移送し、攪拌下に、温度２５０℃、圧力１３３Ｐａで、３時間重縮合反応を進めてポリマーを得た。次いで、窒素圧をかけてストランド状に抜き出し、ペレタイザーで切断することにより、ペレット状のポリブチレンテレフタレートを得た。
得られたポリブチレンテレフタレートの末端カルボキシル基量は４１ｅｑ／ｔであり、降温結晶化温度は１７０℃、残存テトラヒドロフラン量は６８０ｐｐｍ（重量比）、固有粘度は０．８５ｄｌ／ｇであった。
【００８５】
得られたポリブチレンテレフタレート７０重量部、ＰＰＥ３０重量部、ＰＣ２重量部、リン酸エステル化合物１５重量部、シアヌル酸メラミン１５重量部、硼酸亜鉛４重量部、ＧＦ５９重量部、ポリテトラフルオロエチレン１重量部をブレンドし、これを３０ｍｍのベントタイプ二軸押出機（日本製鋼所（株）製、二軸押出機ラボＴＥＸ３０）を使用してバレル温度２７０℃において溶融混練してストランドに押し出した後、ストランドカッターによりペレット化した。得られたペレットを用い、射出成形機（日本製鋼所（株）製、Ｊ２８ＳＡ型）と、ＵＬ９４燃焼試験片用の金型を使用し、シリンダー温度２７０℃、金型温度８０℃にて試験片の成形を行い評価した。
湿熱処理前の引張強度１２４ＭＰａ湿熱処理後の引張強度３５ＭＰａであり、強度保持率は２８％であった。また、難燃性はＶ−０で発生ガス量は２７ｐｐｍであった。結果を表ー１に示した。
【００８６】
比較例４、５
表ー１に示した処方により樹脂組成物を製造し、実施例１と同様にして評価した。結果を表ー１に示した。
【００８７】
【表１】

【００８８】
【表２】

【００８９】
表ー１から明らかなように、テレフタル酸と１，４−ブタンジオールを連続的に重縮合して得られ、本発明に規定する末端カルボキル基量、降温結晶化温度及び残存テトラヒドロフラン量を有するポリブチレンテレフタレートを用いた難燃性ポリブチレンテレフタレート組成物である実施例１、２は、テレフタル酸ジメチルと１，４−ブタンジオールを回分式で重縮合して得られ、本発明の規定範囲外の末端カルボキル基量、降温結晶化温度及び残存テトラヒドロフラン量を有するポリブチレンテレフタレートを用いた難燃性ポリブチレンテレフタレート組成物（比較例３、４）に比べて、難燃性は同等であるが、耐加水分解性に優れている。また発生ガスも少ないことから金属接点の腐食防止効果も大きいと思われる。
ＰＰＥが本発明の規定量より少ない場合（比較例１）は難燃性が劣り、一方、リン酸エステルを本発明の規定量より多くした場合（比較例２）は難燃性はＶ−０であるが、引張強度や耐加水分解性が低下する。
【００９０】
【発明の効果】
本発明のポリブチレンテレフタレートは、成形サイクルが短く生産性に優れ、電気的接点の腐食がなく、とりわけ加水分解に対する安定性が高く、接点腐食性に対して厳しい電気・電子部品などに好適に用いることができる。
【図面の簡単な説明】
【図１】図１は、本発明のポリブチレンテレフタレートを製造する装置の一態様の工程系統図である。
【符号の説明】
１　スラリー調製槽
２　第一エステル化反応槽
３　第二エステル化反応槽
４　第一重縮合反応槽
５　第二重縮合反応槽
６　ペレタイザー[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a flame-retardant polybutylene terephthalate resin composition and a molded product. More specifically, the present invention has high flame retardancy, short molding cycle, excellent productivity, no corrosion of electrical contacts, especially high stability against hydrolysis, and electrical and electronic parts such as relay parts. The present invention relates to a flame-retardant polybutylene terephthalate resin composition containing no bromine or chlorine, and a molded article that can be suitably used.
[0002]
[Prior art]
Polybutylene terephthalate, a representative engineering plastic among thermoplastic polyester resins, has excellent moldability, mechanical properties, heat resistance, and other physical and chemical properties. It is widely used in the fields of electric parts, electronic parts and the like, and it is desired to further improve various characteristics.
For example, polybutylene terephthalate is suitable for injection molding, but if the crystallization temperature can be further increased, the molding cycle can be further shortened and the productivity can be increased. In addition, polybutylene terephthalate is essentially not affected by water at room temperature because of its low hygroscopicity. However, at high temperatures, ester groups are hydrolyzed by water or water vapor to form hydroxyl groups and carboxyl groups, and carboxyl groups become autocatalysts to promote hydrolysis, thus limiting their use under wet heat conditions. . In addition, when a large amount of organic gas is generated from polybutylene terephthalate, when used in electric and electronic parts such as relay parts, corrosion of metal contacts and adhesion of carbide to metal contacts may be caused to cause poor conduction. . Therefore, polybutylene terephthalate which has low hydrolyzability and generates little organic gas is desired.
[0003]
Further, in the above-mentioned applications, a flame-retardant material is required. In recent years, electric / electronic parts, automobile parts, and other electric parts have been thinned and miniaturized, and various molded products used therein have also been thinned and miniaturized. In many cases, flame retardancy corresponding to the part is required.
Conventionally, bromine or chlorine-based organic flame retardants have been widely used as flame retardants for polyester resins. However, molded articles containing these halogen-containing flame retardants are toxic and corrosive when burning. It has the disadvantage of generating large amounts of hydrogen hydride or hydrogen chloride gas and black smoke.
As non-brominated or non-chlorinated flame retardants, hydrated inorganic compounds such as magnesium hydroxide and aluminum hydroxide are known, but these hydrated inorganic compounds are more flame-retardant than brominated or chlorinated flame retardants. Due to the low effect, it is necessary to add a large amount to the resin in order to produce a product with high flame retardancy, which has the drawback of significantly deteriorating the mechanical properties and moldability inherent to the resin. Was.
[0004]
A method using a nitrogen compound having a triazine ring (JP-B-58-5939 and JP-B-60-33850) is also known, but not only has a low flame-retardant effect, but also has a low mechanical property. There have been problems such as remarkable lowering, mold contamination and bleeding out to the resin surface.
[0005]
Further, various phosphorus compounds are also known as non-bromine or non-chlorine flame retardants. Although red phosphorus has a high flame-retardant effect, it can exhibit high flame retardancy by adding a relatively small amount, but the product is colored red and the mechanical properties of the polyester resin deteriorate under high temperature and high humidity. It was not sufficient in practical terms, such as making it work. At the time of pellet drying and molding, harmful gas phosphine (PH) is used. ₃ ) Occurred, and there was also a problem in the working environment.
[0006]
Various methods using a phosphoric ester-based flame retardant (JP-B-51-19858, JP-B-51-39271, etc.) are also known, but the flame retardant effect is higher than that of a bromine-based or chlorine-based flame retardant. Insufficient, it is necessary to add a large amount to the resin in order to express a high level of flame retardancy, which drastically reduces the crystallinity of the resin, significantly reducing the mechanical properties and moldability of the resin However, the phosphoric ester-based flame retardant has a drawback that the hydrolysis resistance of the polyester resin is extremely reduced. In addition, phosphate ester flame retardants added in large amounts to exhibit high flame retardancy not only violently plate out during molding, but also bleed out to the product surface and generate large amounts of organic gas. It was also the cause of failure and contact failure.
[0007]
Japanese Patent Application Laid-Open No. Sho 60-47056 discloses that in order to supplement the low flame retardant effect of such a phosphate ester flame retardant, in addition to a thermoplastic linear polyester resin and an organic phosphate ester, a polyphenylene ether resin, a bromine-based or chlorine-based flame retardant is used. Although a flame-retardant polyester composition comprising a flame retardant has been disclosed, there have been problems such as generation of a large amount of black smoke and irritating gas when burning with a bromine-based or chlorine-based flame retardant.
[0008]
[Problems to be solved by the invention]
Under such circumstances, the present invention has been made to solve the above-mentioned disadvantages of the prior art. INDUSTRIAL APPLICABILITY The present invention has high flame retardancy, has a short molding cycle, is excellent in productivity, does not corrode electrical contacts, has high stability especially against hydrolysis, and is suitably used for electric and electronic parts such as relay parts. It is an object of the present invention to provide a flame-retardant polybutylene terephthalate resin composition and a molded article which do not contain a bromine or chlorine-based flame retardant.
[0009]
[Means for Solving the Problems]
The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, the amount of terminal carboxyl groups is 30 eq / t or less, the temperature-reducing crystallization temperature is 175 ° C. or more, and the amount of residual tetrahydrofuran is 300 ppm (weight ratio) or less. A resin composition containing a specific flame retardant and a flame retardant auxiliary in a certain polybutylene terephthalate has a short molding cycle, hardly corrodes electrical contacts, and has excellent stability against hydrolysis. It has been found that a resin composition containing a non-halogen flame retardant and a specific non-halogen flame retardant can satisfy the above object, and have reached the present invention.
That is, the gist of the present invention is that (A) the amount of terminal carboxyl groups is 30 eq / t or less and the temperature-fall crystallization temperature is 175 ° C. or more, or the temperature-fall crystallization temperature is 175 ° C. or more and the amount of residual tetrahydrofuran (C) 0.05 to 10 parts by weight of a compatibilizer with respect to 100 to 50 parts by weight of a polybutylene terephthalate having a content of 300 ppm or less and 100 to 50 parts by weight of a polyphenylene ether resin (B). (D) 2 to 45 parts by weight of at least one compound selected from phosphate esters or phosphonitrile, (E) 0 to 150 parts by weight of a reinforcing filler, (F) 0.001 to 15 parts by weight of an anti-drip agent, G) a flame-retardant polybutylene terephthalate resin composition containing 0 to 45 parts by weight of melamine cyanurate and (H) 0 to 50 parts by weight of a metal borate; To.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail.
The first embodiment of the polybutylene terephthalate (A) used in the present invention is a polybutylene terephthalate having a terminal carboxyl group content of 30 eq / t or less and a temperature-lowering crystallization temperature of 175 ° C. or more. An embodiment is polybutylene terephthalate having a temperature-reducing crystallization temperature of 175 ° C. or more and a residual tetrahydrofuran amount of 300 ppm (weight ratio) or less. Preferably, the polybutylene terephthalate (A) used in the present invention has a terminal carboxyl group content of 30 eq / t or less, a temperature-reducing crystallization temperature of 175 ° C. or more, and a residual tetrahydrofuran content of 300 ppm (weight ratio) or less. It is.
[0011]
The amount of terminal carboxyl groups of (A) polybutylene terephthalate (may be abbreviated as PBT) used in the present invention is 30 eq / t or less, more preferably 25 eq / t or less. The amount of terminal carboxyl groups of polybutylene terephthalate can be determined by dissolving PBT in an organic solvent and titrating with an alkali hydroxide solution. In the present invention, the hydrolysis resistance of PBT can be increased by controlling the amount of terminal carboxyl groups to 30 eq / t or less. Since the carboxyl group in the PBT acts as an autocatalyst for the hydrolysis of polybutylene terephthalate, if a terminal carboxyl group of more than 30 eq / t is present, hydrolysis starts early, and the generated carboxyl group becomes an autocatalyst. The hydrolysis progresses in a chain and the degree of polymerization of PBT rapidly decreases. However, by controlling the amount of terminal carboxyl groups to 30 eq / t or less, even under conditions of high temperature and high humidity, early hydrolysis occurs. Can be suppressed.
[0012]
The temperature-reducing crystallization temperature of the polybutylene terephthalate (A) used in the present invention is at least 175 ° C, more preferably at least 177 ° C. In the present invention, the cooling crystallization temperature means a value obtained by measuring the temperature of a melted polybutylene terephthalate at a cooling rate of 20 ° C./min using a differential scanning calorimeter. The cooling crystallization temperature means a temperature of an exothermic peak due to crystallization that appears when the molten PBT is cooled. The crystallization temperature corresponds to the crystallization speed, and the higher the cooling crystallization temperature, the faster the crystallization speed. When the cooling crystallization temperature of PBT is 175 ° C. or higher, the cooling time can be shortened and the productivity can be improved when the resin composition containing the PBT is injection-molded. If the temperature-reducing crystallization temperature is lower than 175 ° C., it takes a long time for crystallization during injection molding, and the cooling time after injection molding must be lengthened, and the molding cycle may be extended and productivity may be reduced. The molding cycle can be evaluated by performing injection molding under certain molding conditions and evaluating the ease of release of molded pieces and the presence or absence of protrusion pin traces. If it occurs, the mold release becomes impossible at a later time.
[0013]
The amount of residual tetrahydrofuran in (A) polybutylene terephthalate used in the present invention is 300 ppm (weight ratio) or less, and more preferably 200 ppm (weight ratio) or less. The amount of residual tetrahydrofuran can be determined by immersing the PBT pellet in water, treating it at 120 ° C. for 6 hours, and quantifying the amount of tetrahydrofuran eluted in water by gas chromatography. By setting the amount of residual tetrahydrofuran in the PBT to 300 ppm (weight ratio) or less, when a molded article obtained from the resin composition of the present invention is used at a high temperature, generation of organic gas is small and corrosion of electrical contacts is prevented. It is less likely to be used and can be suitably used for electric and electronic parts such as relay parts. When the amount of residual tetrahydrofuran exceeds 300 ppm (weight ratio), generation of organic gas when the molded article is used at a high temperature increases, which may cause metal corrosion.
Although the lower limit of the amount of residual tetrahydrofuran is not particularly limited, it is usually about 50 ppm (weight ratio). Although the smaller the amount of residual tetrahydrofuran, the smaller the amount of organic gas generated tends to be. However, the amount of residual gas and the amount of gas generated are not always proportional, and the presence of about 50 ppm of tetrahydrofuran does not pose a problem for ordinary use. Rather, it is known that the presence of a small amount of diol suppresses corrosion of electrical contacts (JP-A-8-20900), and a similar effect is expected for tetrahydrofuran.
[0014]
The polybutylene terephthalate (A) used in the present invention has an intrinsic viscosity of 0.3 measured at 30 ° C. using a mixed solvent of phenol / 1,1,2,2-tetrachloroethane (weight ratio 1/1). It is preferably from 5 to 1.5 dl / g, more preferably from 0.6 to 1.3 dl / g, even more preferably from 0.7 to 1.1 dl / g. If the intrinsic viscosity is less than 0.5 dl / g, the mechanical strength of a molded article using the resin composition of the present invention may be insufficient. If the intrinsic viscosity exceeds 1.5 dl / g, the melt viscosity increases, the flowability deteriorates, and the moldability may deteriorate.
[0015]
The polybutylene terephthalate (A) of the present invention having the above-mentioned properties can be obtained, for example, by a continuous polymerization method using terephthalic acid and 1,4-butanediol as main raw materials. The main raw material means that terephthalic acid accounts for 50 mol% or more of the total dicarboxylic acid component and 1,4-butanediol accounts for 50 mol% or more of the total diol component. Terephthalic acid more preferably accounts for 80 mol% or more of the total dicarboxylic acid component, and still more preferably accounts for 95 mol% or more. 1,4-butanediol more preferably accounts for 80 mol% or more of the total diol component, and even more preferably accounts for 95 mol% or more.
In the present invention, there is no particular limitation on dicarboxylic acid components other than terephthalic acid. For example, phthalic acid, isophthalic acid, 4,4′-diphenyldicarboxylic acid, 4,4′-diphenylether dicarboxylic acid, 4,4′-benzophenone dicarboxylic acid Acids, aromatic dicarboxylic acids such as 4,4'-diphenoxyethanedicarboxylic acid, 4,4'-diphenylsulfonedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexane Alicyclic dicarboxylic acids such as dicarboxylic acid and 1,4-cyclohexanedicarboxylic acid, and aliphatic dicarboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid. be able to.
[0016]
In the present invention, diol components other than 1,4-butanediol are not particularly limited. For example, ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, 1,3-propanediol, polytetramethylene ether glycol, 1,5- Aliphatic diols such as pentanediol, neopentyl glycol, 1,6-hexanediol, 1,8-octanediol, 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,1-cyclohexanedimethylol, Alicyclic diols such as 4-cyclohexane dimethylol, xylylene glycol, aromatic diols such as 4,4'-dihydroxybiphenyl, 2,2-bis (4-hydroxyphenyl) propane and bis (4-hydroxyphenyl) sulfone Oars and the like can be mentioned.
In the present invention, further, hydroxycarboxylic acid such as glycolic acid, m-hydroxybenzoic acid, p-hydroxybenzoic acid, 6-hydroxy-2-naphthalenecarboxylic acid, p-β-hydroxyethoxybenzoic acid, alkoxycarboxylic acid, Monofunctional components such as stearyl alcohol, benzyl alcohol, stearic acid, benzoic acid, t-butyl benzoic acid, and benzoyl benzoic acid, tricarballylic acid, trimellitic acid, trimesic acid, pyromellitic acid, gallic acid, trimethylolethane, and trimethylol A trifunctional or higher polyfunctional component such as methylolpropane, glycerol, and pentaerythritol can be used as a copolymer component.
[0017]
The polybutylene terephthalate (A) used in the present invention is a resin obtained by continuously polymerizing a dicarboxylic acid component mainly containing terephthalic acid and a diol component mainly containing 1,4-butanediol. Preferably, there is. The continuous polymerization method for producing the polybutylene terephthalate of the present invention is not particularly limited, but it is preferable to carry out continuous polymerization using a serial continuous tank reactor. For example, a dicarboxylic acid component and a diol component are preferably heated to a temperature of 150 to 280 ° C, more preferably 180 to 265 ° C, in the presence of an esterification reaction catalyst in one or more esterification reaction vessels. Is subjected to an esterification reaction at a pressure of 6.67 to 133 kPa, more preferably 9.33 to 101 kPa for 2 to 5 hours with stirring, and the resulting esterification reaction product oligomer is transferred to a polycondensation reaction tank. And in a polycondensation reaction tank of one or more groups, in the presence of a polycondensation reaction catalyst, preferably at a temperature of 210 to 280 ° C, more preferably 220 to 265 ° C, preferably 26.7 kPa or less, more preferably Can be subjected to a polycondensation reaction under reduced pressure of 20 kPa or less for 2 to 5 hours with stirring. The polybutylene terephthalate obtained by the polycondensation reaction is transferred from the bottom of the polycondensation reaction tank to a polymer extraction die, extracted in a strand shape, and cooled with water or after being cooled with water, then cut with a pelletizer to form a pellet. And the like.
The type of the esterification reaction tank used in the present invention is not particularly limited, and examples thereof include a vertical stirring complete mixing tank, a vertical thermal convection mixing tank, and a tower-type continuous reaction tank. The esterification reaction tank may be a single tank, or a plurality of tanks of the same type or different types in series. The type of the polycondensation reaction tank used in the present invention is not particularly limited, and examples thereof include a vertical stirring polymerization tank, a horizontal stirring polymerization tank, and a thin-film evaporation polymerization tank. The polycondensation reaction tank may be a single tank, or may be a plurality of tanks in which a plurality of tanks of the same type or different types are connected in series.
[0018]
FIG. 1 shows a process flow chart of one embodiment of an apparatus for producing polybutylene terephthalate used in the present invention. Terephthalic acid, 1,4-butanediol and an esterification reaction catalyst are supplied to a slurry preparation tank 1 and stirred and mixed to prepare a slurry. The prepared slurry is continuously transferred to the first esterification reaction tank 2 and becomes an oligomer by the esterification reaction. In this figure, for the sake of simplification, auxiliary equipment such as a pump, a rectification tower, and a cooling bath are not shown. The oligomer is continuously transferred from the first esterification reaction tank to the second esterification reaction tank 3, where 1,4-butanediol is distilled off to become an oligomer having a higher molecular weight. The oligomer in the second esterification reaction tank is continuously transferred to the first polycondensation reaction tank 4, where the polycondensation reaction proceeds to become a prepolymer. The prepolymer in the first polycondensation reaction tank is continuously transferred to the second double condensation reaction tank 5, and the polycondensation reaction is further advanced to obtain the polybutylene terephthalate of the present invention having a predetermined degree of polymerization. The resin is transferred from the bottom of the second double condensation reaction tank to a die, extracted in a strand shape, and cut by a pelletizer 6 to form resin pellets.
[0019]
The esterification reaction catalyst used is not particularly limited, and examples thereof include a titanium compound, a tin compound, a magnesium compound, and a calcium compound. Among them, a titanium compound can be particularly preferably used. Examples of the titanium compound used as the esterification catalyst include titanium alcoholates such as tetramethyl titanate, tetraisopropyl titanate and tetrabutyl titanate, and titanium phenolates such as tetraphenyl titanate. The amount of the titanium compound catalyst used is, for example, in the case of tetrabutyl titanate, preferably 30 to 300 ppm (weight ratio) as titanium atoms, and 50 to 200 ppm (weight ratio) with respect to the theoretical yield of polybutylene terephthalate. It is more preferable to use.
As the polycondensation reaction catalyst, the esterification reaction catalyst added during the esterification reaction can be subsequently used as the polycondensation reaction catalyst without adding a new catalyst, or the esterification reaction catalyst can be used during the polycondensation reaction. A catalyst which is the same as or different from the sometimes added esterification reaction catalyst may be further added. For example, when tetrabutyl titanate is further added, its use amount is preferably not more than 300 ppm (weight ratio) as titanium atoms, and not more than 150 ppm (weight ratio), based on the theoretical yield of polybutylene terephthalate. Is more preferable. Examples of the polycondensation reaction catalyst different from the esterification reaction catalyst include an antimony compound such as diantimony trioxide and a germanium compound such as germanium dioxide and germanium tetroxide.
[0020]
In the esterification reaction and / or polycondensation reaction, besides the above-mentioned catalyst, orthophosphoric acid, phosphorous acid, hypophosphorous acid, polyphosphoric acid, or a phosphorus compound such as an ester or metal salt thereof, sodium hydroxide, benzoic acid Reaction aids such as alkali metal or alkaline earth metal compounds such as sodium acid, magnesium acetate and calcium acetate, 2,6-di-t-butyl-4-octylphenol, pentaerythrityltetrakis [3- (3 ′, 5 Phenol compounds such as'-t-butyl-4'-hydroxyphenyl)propionate]; thioether compounds such as dilauryl-3,3'-thiodipropionate; pentaerythrityltetrakis (3-laurylthiodipropionate); Phenyl phosphite, tris (nonylphenyl) phosphite, tris (2,4-di-t- Antioxidants such as phosphorus compounds such as butylphenyl) phosphite, paraffin wax, microcrystalline wax, polyethylene wax, long-chain fatty acids such as montanic acid and montanic acid esters or esters thereof, and release agents such as silicone oil Can be present.
[0021]
Methods for producing polybutylene terephthalate include a method involving transesterification of dimethyl terephthalate or the like with 1,4-butanediol and a method involving direct esterification of terephthalic acid with 1,4-butanediol. However, direct esterification using terephthalic acid and 1,4-butanediol as starting materials is advantageous from the viewpoint of raw material costs. In addition, according to the direct esterification reaction using terephthalic acid and 1,4-butanediol as starting materials, polybutylene terephthalate having a higher temperature and lower crystallization temperature can be easily obtained as compared with a method involving a transesterification reaction. .
Methods for producing polybutylene terephthalate include a batch reaction and a continuous reaction. The batch reaction is a method in which a transesterification reaction or an esterification reaction and a polycondensation reaction are performed in a batch system, and the continuous reaction is a method in which an esterification reaction and a polycondensation reaction are continuously performed. The method of continuously polymerizing terephthalic acid and 1,4-butanediol causes a decrease in molecular weight, an increase in the amount of terminal carboxyl groups, and an increase in the amount of residual tetrahydrofuran with time withdrawal from the reaction vessel after the reaction. It is preferable because a high-quality resin can be easily obtained without performing the above-described process.
[0022]
The component (B) polyphenylene ether resin (hereinafter abbreviated as PPE) used for producing the flame-retardant polybutylene terephthalate resin composition of the present invention is a homopolymer or a copolymer having a structure represented by the following general formula. It is a polymer.
[0023]
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[0024]
(Where R ¹⁰ Represents a hydrogen atom, a primary or secondary alkyl group, an aryl group, an aminoalkyl group, a hydrocarbonoxy group, ¹¹ Represents a primary or secondary alkyl group, aryl group or alkylamino group. r represents an integer of 10 or more. ).
R ¹⁰ As the primary alkyl group represented by, for example, methyl, ethyl, n-propyl, n-butyl, n-amyl, n-hexyl, isoamyl, 2-methylbutyl, 2,3-dimethylbutyl, 2,3- Or 4-methylpentyl or heptyl. Suitable examples of the secondary alkyl group include isopropyl, sec-butyl, or 1-ethylpropyl. Suitable PPE homopolymers are, for example, those comprising 2,6-dimethyl-1,4-phenylene ether units. A preferred copolymer is a random copolymer comprising a combination of the above units and 2,3,6-trimethyl-1,4-phenylene ether units.
[0025]
The PPE of the component (B) used in the present invention preferably has an intrinsic viscosity at 30 ° C measured in chloroform of 0.2 to 0.8 dl / g, more preferably an intrinsic viscosity of 0.25 to 0.8 dl / g. It is preferably 0.7 dl / g, particularly preferably 0.3 to 0.6 dl / g. If the intrinsic viscosity is less than 0.2 dl / g, the impact resistance of the composition will be insufficient, and if it exceeds 0.8 dl / g, the gel component will be large and the appearance of the molded article tends to deteriorate.
The amount of the component (B) PPE is such that the weight ratio with respect to the component (A) polybutylene terephthalate is (A) :( B) = 95: 5 to 50:50, preferably 92: 8 to 55: 45, particularly preferably 90:10 to 60:40. If the ratio of (B) is less than 5, the flame retardancy and hydrolysis resistance of the composition will be insufficient, and if it is more than 50, the fluidity and chemical resistance of the composition will be significantly reduced.
[0026]
The component (C) compatibilizer used for producing the flame-retardant polyester resin composition of the present invention is a compound that improves the dispersibility of PPE in polybutylene terephthalate, and includes a polycarbonate resin, a carboxyl group, A compound having at least one functional group selected from a carboxylic acid ester group, an acid amide group, an imide group, an acid anhydride group, an epoxy group, an oxazolinyl group, an amino group and a hydroxyl group, a phosphite compound and the like can be used. Specific examples of the compound having a functional group include an epoxy group-added PPE resin, a hydroxyalkylated PPE resin, an oxazoline-terminated PPE resin, a polyester having a carboxyl group terminal modified by polystyrene, and a polyester having an OH group terminal modified by polyethylene. And the like. As the compatibilizer (C), a phosphite or a polycarbonate resin is preferable from the viewpoint of hydrolysis resistance, crystallinity, mechanical properties, and flame retardancy of the composition of the present invention. Phosphoric acid triesters are preferable, and particularly, phosphite triesters represented by the following general formulas (3) and (4) are suitably used.
[0027]
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[0028]
(Where R ¹² ~ R ¹⁴ Each independently represents an alkyl group having 1 to 20 carbon atoms or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, which may contain an oxygen atom, a nitrogen atom, and a sulfur atom. ).
Specific examples of the general formula (3) include trioctyl phosphite, tridecyl phosphite, trilauryl phosphite, tristearyl phosphite, triisooctyl phosphite, tris (nonylphenyl) phosphite, and tris (2,4 -Dinonylphenyl) phosphite, tris (2,4-di-tert-butylphenyl) phosphite, triphenylphosphite, tris (octylphenyl) phosphite, diphenylisooctylphosphite, diphenylisodecylphosphite, octyl Examples include diphenyl phosphite, dilauryl phenyl phosphite, diisodecyl phenyl phosphite, bis (nonylphenyl) phenyl phosphite, diisooctyl phenyl phosphite and the like.
[0029]
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[0030]
Wherein u is 1 or 2; ^Fifteen Represents an alkyl group having 1 to 20 carbon atoms or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms which may be the same or different and may contain an oxygen atom, a nitrogen atom or a sulfur atom. R ¹⁶ Represents a C1-C20 alkylene group or a C6-C30 substituted or unsubstituted arylene group when u is 1, and a C4-C18 alkyltetrayl group when u is 2 . ).
R ^Fifteen Examples of methyl, ethyl, propyl, octyl, isooctyl, isodecyl, decyl, stearyl, lauryl, phenyl, 2,3- or 4-methylphenyl, 2,4- or 2,6-dimethylphenyl, 2,3 , 6-Trimethylphenyl, 2-, 3- or 4-ethylphenyl, 2-, 4- or 2-, 6-diethylphenyl, 2,3,6-triethylphenyl, 2-, 3- or 4-tert- Butylphenyl, 2,4- or 2,6-di-tert-butylphenyl, 2,6-di-tert-butyl-4-methylphenyl, 2,6-di-tert-butyl-4-ethylphenyl, octyl Phenyl, isooctylphenyl, 2-, 3- or 4-nonylphenyl, 2,4-dinonylphenyl, biphenyl, naphthy Etc., and among them substituted or unsubstituted aryl group are preferred.
R ¹⁶ In the general formula (4), when u = 1, a 1,2-phenylene group, and a polymethylene group such as ethylene, propylene, trimethylene, tetramethylene, and hexamethylene are exemplified.
[0031]
As specific examples of the compound of the general formula (4), when u is 1, for example, (phenyl) (1,3-propanediol) phosphite, (4-methylphenyl) (1,3-propanediol) phosphite , (2,6-dimethylphenyl) (1,3-propanediol) phosphite, (4-tert-butylphenyl) (1,3-propanediol) phosphite, (2,4-di-tert-butylphenyl) ) (1,3-propanediol) phosphite, (2,6-di-tert-butylphenyl) (1,3-propanediol) phosphite, (2,6-di-tert-butyl-4-methylphenyl) ) (1,3-propanediol) phosphite, (phenyl) (1,2-ethanediol) phosphite, (4-methylphenyl) (1,2-ethane Diol) phosphite, (2,6-dimethylphenyl) (1,2-ethanediol) phosphite, (4-tert-butylphenyl) (1,2-ethanediol) phosphite, (2,6-di- tert-butylphenyl) (1,2-ethanediol) phosphite, (2,6-di-tert-butyl-4-methylphenyl) (1,2-ethanediol) phosphite, (2,6-di- tert-butyl-4-methylphenyl) (1,4-butanediol) phosphite and the like.
When u = 2, R ¹⁶ Is a tetrayl group having a pentaerythrityl structure represented by the following general formula (5).
[0032]
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[0033]
(In the formula, v, w, x, and y each represent an integer of 0 to 6.)
Specific examples include diisodecylpentaerythritol diphosphite, dilaurylpentaerythritol diphosphite, distearylpentaerythritol diphosphite, diphenylpentaerythritol diphosphite, bis (2-methylphenyl) pentaerythritol diphosphite, and bis ( 3-methylphenyl) pentaerythritol diphosphite, bis (4-methylphenyl) pentaerythritol diphosphite, bis (2,4-dimethylphenyl) pentaerythritol diphosphite, bis (2,6-dimethylphenyl) pentaerythritol Diphosphite, bis (2,3,6-trimethylphenyl) bantaerythritol diphosphite, bis (2-tert-butylphenyl) pentaerythritol diphospha Bis (3-tert-butylphenyl) pentaerythritol diphosphite, bis (4-tert-butylphenyl) pentaerythritol diphosphite, bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite Bis (2,6-di-tert-butylphenyl) pentaerythritol diphosphite, bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, bis (2,6-diphenyl) -Tert-butyl-4-ethylphenyl) pentaerythritol diphosphite, bis (nonylphenyl) pentaerythritol diphosphite, bis (biphenyl) pentaerythritol diphosphite, dinaphthylpentaerythritol diphosphite and the like.
[0034]
Among these phosphite triesters, compounds in which u is 1 or 2 in the formula (4) are preferable, and further, when u = 2 in the formula (4), R ¹⁶ Is more preferably a tetrayl group having a pentaerythrityl structure represented by the general formula (5). Among them, bis (nonylphenyl) pentaerythritol diphosphite, bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite, bis (2,6-di-tert-butyl-4-methylphenyl) Pentaerythritol diphosphite and the like are more preferable, and particularly, bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite and bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol Diphosphite and the like are preferably used.
The composition of the present invention may contain a compound generated by the decomposition (hydrolysis, thermal decomposition, etc.) of these phosphite triesters.
[0035]
The polycarbonate resin used as the component (C) compatibilizer includes an aromatic dihydroxy compound or an optionally branched thermoplastic resin produced by reacting an aromatic dihydroxy compound or a small amount of the polyhydroxy compound with phosgene or a carbonic acid diester. An aromatic polycarbonate polymer or copolymer is exemplified.
[0036]
As aromatic dihydroxy compounds, 2,2-bis (4-hydroxyphenyl) propane (= bisphenol A), tetramethylbisphenol A, bis (4-hydroxyphenyl) -p-diisopropylbenzene, hydroquinone, resorcinol, 4,4 -Dihydroxydiphenyl and the like, preferably bisphenol A.
[0037]
To obtain a branched polycarbonate resin, phloroglucin, 4,6-dimethyl-2,4,6-tri (4-hydroxyphenyl) heptene-2,4,6-dimethyl-2,4,6-tri (4- (Hydroxyphenyl) heptane, 2,6-dimethyl-2,4,6-tri (4-hydroxyphenyl) heptene-3,1,3,5-tris (4-hydroxyphenyl) benzene, 1,1,1-tris Polyhydroxy compounds represented by (4-hydroxyphenyl) ethane or the like, 3,3-bis (4-hydroxyaryl) oxindole (= isatin bisphenol), 5-chlorisatin, 5,7-dichlorisatin, 5-bromoisatin, etc. May be used as a part of the aromatic dihydroxy compound, and the amount used is 0.01 to 10 mol%. Preferably 0.1 to 2 mol%.
[0038]
To adjust the molecular weight of the polycarbonate, a monovalent aromatic hydroxy compound may be used, such as m- and p-methylphenol, m- and p-propylphenol, p-tert-butylphenol and p-long-chain alkyl-substituted phenol. Is mentioned.
The aromatic polycarbonate resin is preferably a polycarbonate resin derived from 2,2-bis (4-hydroxyphenyl) propane, or a resin derived from 2,2-bis (4-hydroxyphenyl) propane and another aromatic dihydroxy compound. Polycarbonate copolymer to be used.
The molecular weight of the polycarbonate resin used as the compatibilizer (C) of the present invention is 16,000 to 30,000 as a viscosity average molecular weight calculated from a solution viscosity measured at a temperature of 25 ° C. using methylene chloride as a solvent. And more preferably 18,000 to 23,000. As the polycarbonate resin, a mixture of two or more kinds of polycarbonate resins can be used.
[0039]
The amount of the component (C) compatibilizer is 0.05 to 10 parts by weight, preferably 0.1 to 8 parts by weight, and particularly preferably 100 parts by weight of the total of the components (A) and (B). 0.3 to 5 parts by weight. If the amount of the component (C) compatibilizer is less than 0.05 part by weight, physical properties, particularly mechanical strength and flame retardancy, of the resin composition of the present invention are reduced. Of the surface appearance is deteriorated.
[0040]
The component (D) phosphate compound used in the present invention includes a wide range of phosphate esters, and specific examples thereof include, for example, trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, tributoxyethyl phosphate, and tributyl phosphate. Phenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, and the like can be mentioned, and among them, a compound represented by the following general formula (1) is preferable.
[0041]
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[0042]
(Where R ¹ ~ R ⁸ Each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and m is 0 or an integer of 1 to 4. R ⁹ Is a p-phenylene group, an m-phenylene group, a 4,4′-biphenylene group or a divalent group selected from the following. ).
[0043]
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[0044]
In the general formula (1), R ¹ ~ R ⁸ In order to improve the hydrolysis resistance of the composition of the present invention, an alkyl group having 6 or less carbon atoms is preferable, and an alkyl group having 2 or less carbon atoms, particularly a methyl group, is preferable. m is preferably 1 to 3, and more preferably 1. R ⁹ Among them, p-phenylene group and m-phenylene group are preferable, and m-phenylene group is particularly preferable.
As the component (D), a phosphonitrile compound having a group represented by the following general formula (6) is also suitably used.
[0045]
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[0046]
(Wherein, X represents —O—, —S—, —NH— or a direct bond; R ¹⁷ And R ¹⁸ Represents an aryl group, an alkyl group, or a cycloalkyl group having 1 to 20 carbon atoms. R ¹⁷ -X-, R ¹⁸ -X- may be the same or different. n shows the integer of 1-12. ).
In the general formula (6), R ¹⁷ , R ¹⁸ Specific examples include an optionally substituted alkyl group such as methyl, ethyl, butyl, hexyl and benzyl; a cycloalkyl group such as cyclohexyl; and an aryl group such as phenyl and naphthyl. n is preferably 3 to 10, and particularly preferably 3 or 4. The phosphonitrile compound of the general formula (6) may be a linear polymer or a cyclic polymer, and among them, a cyclic polymer is preferably used. X is preferably -O- or -NH-, particularly preferably -O-.
Specific examples of the phosphonitrile compound represented by the general formula (6) include, for example, hexaphenoxycyclotriphosphazene, hexa (hydroxyphenoxy) cyclotriphosphazene, octaphenoxycyclotetraphosphazene, and octa (hydroxyphenoxy) cyclotetraphosphazene. Can be
[0047]
The amount of the component (D) is 2 to 45 parts by weight, preferably 3 to 40 parts by weight, particularly preferably 5 to 30 parts by weight based on 100 parts by weight of the total of (A) and (B). When the amount of (D) is less than 2 parts by weight, the flame retardancy of the composition becomes insufficient, and when it is more than 45 parts by weight, mechanical properties, hydrolysis resistance and moldability are remarkably reduced.
[0048]
The composition of the present invention preferably contains (E) a reinforcing filler. The type of the (E) reinforcing filler used is not particularly limited, and various fillers used for reinforcing the resin are used. Specifically, for example, glass fiber, carbon fiber, silica / alumina fiber, zirconia fiber, boron fiber, boron nitride fiber, potassium silicon nitride titanate fiber, inorganic fiber such as metal fiber, aromatic polyamide fiber, fluororesin fiber And other organic fibers. One of these reinforcing fillers can be used alone, or two or more of them can be used in combination. Among these, an inorganic filler can be preferably used, and glass fiber can be particularly preferably used. When the reinforcing filler is an inorganic fiber or an organic fiber, the average fiber diameter is not particularly limited, but is preferably 1 to 100 μm, more preferably 2 to 50 μm, and more preferably 3 to 30 μm. More preferably, it is particularly preferably 5 to 20 μm. The average fiber length is not particularly limited, but is preferably 0.1 to 20 mm, more preferably 1 to 10 mm. In order to improve the interfacial adhesion with polybutylene terephthalate, the reinforcing filler is preferably used after surface treatment with a sizing agent or a surface treatment agent. Examples of the sizing agent or the surface treatment agent include functional compounds such as an epoxy compound, an acrylic compound, an isocyanate compound, a silane compound, and a titanate compound. (E) The reinforcing filler may be surface-treated in advance with a sizing agent or a surface treating agent, or may be converged together with the (E) reinforcing filler during the preparation of the polybutylene terephthalate resin composition of the present invention. Surface treatment can also be performed by adding an agent or a surface treatment agent. The amount of the reinforcing filler is 0 to 150 parts by weight, preferably 5 to 100 parts by weight, based on 100 parts by weight of the total of (A) polybutylene terephthalate and (B) PPE.
[0049]
In the flame-retardant polybutylene terephthalate resin composition of the present invention, other fillers can be blended together with the reinforcing filler (E). As other fillers to be blended, for example, plate-like inorganic fillers, ceramic beads, asbestos, wollastonite, talc, clay, mica, zeolite, kaolin, potassium titanate, barium sulfate, titanium oxide, silicon oxide, oxide Aluminum and magnesium hydroxide can be exemplified. By blending the plate-like inorganic filler, the anisotropy and warpage of the molded product can be reduced. Examples of the plate-like inorganic filler include glass flakes, mica, and metal foil. Among these, glass flakes can be particularly preferably used.
[0050]
The (F) anti-dripping agent used in the present invention refers to a compound having a property of preventing dripping of a resin during combustion, and specific examples thereof include silicone oil, silica, asbestos, fluororesin, talc, Examples include layered silicates such as mica. Among them, preferred from the viewpoint of flame retardancy of the composition are fluorine-containing polymers, layered silicates, and the like.
[0051]
The amount of the component (F) anti-dripping agent is selected from the range of 0.001 to 15 parts by weight based on 100 parts by weight of the total of the components (A) and (B). If the amount of the anti-dripping agent is small, the effect of preventing dripping during combustion is insufficient, and if it is too large, there is a fear that the fluidity and mechanical properties may be reduced.
[0052]
(F) Examples of the fluororesin used as an anti-dripping agent include polytetrafluoroethylene, tetrafluoroethylene / perfluoroalkylvinyl ether copolymer, tetrafluoroethylene / hexafluoropropylene copolymer, and tetrafluoroethylene / ethylene copolymer. Preferred are fluorinated polyolefins such as coalesced vinylidene fluoride and polychlorotrifluoroethylene, among which polytetrafluoroethylene, tetrafluoroethylene / perfluoroalkylvinyl ether copolymer, tetrafluoroethylene / hexafluoropropylene copolymer, tetrafluoroethylene Ethylene / ethylene copolymer is more preferable, and particularly, polytetrafluoroethylene and tetrafluoroethylene / hexafluoropropylene copolymer are suitably used.
[0053]
(F) The fluororesin used as an anti-drip agent has a melt viscosity at 350 ° C. of 1.0 × 10 ² ~ 1.0 × 10 ^Fifteen (Pa · s) is preferable, and 1.0 × 10 ³ ~ 1.0 × 10 ¹⁴ (Pa · s), especially 1.0 × 10 ¹⁰ ~ 1.0 × 10 ¹² (Pa · s) is preferably used. Melt viscosity is 1.0 × 10 ² If it is less than (Pa · s), the ability to prevent dripping during combustion is insufficient, and ^Fifteen If it is larger than (Pa · s), the fluidity of the composition is remarkably reduced, which is not preferable.
[0054]
The amount of the fluororesin is 0.001 to 15 parts by weight, preferably 0.005 to 12 parts by weight, particularly 0.01 to 10 parts by weight based on 100 parts by weight of the total of the components (A) and (B). Parts by weight are preferred. If the amount of the fluororesin is less than 0.001 part by weight, the effect of preventing dripping during combustion is insufficient, and if it is more than 15 parts by weight, the fluidity and mechanical properties are reduced.
[0055]
It is preferable to use a layered silicate as the component (F) anti-dripping agent from the viewpoint of fluidity during melting of the resin composition of the present invention. Examples of the layered silicate include a layered silicate, a modified layered silicate (a layered silicate having a quaternary organic onium cation inserted between layers), a layered silicate having a reactive functional group, or a modified layered silicate. From the viewpoint of the dispersibility of the layered silicate in the resin composition of the present invention and the ability to prevent dripping, a modified layered silicate, a layered silicate to which a reactive functional group is added, or a modified layered silicate is preferable. A layered silicate or a modified layered silicate to which a reactive functional group such as a group, an oxazoline group, a carboxyl group, or an acid anhydride is added is preferably used. The method for imparting a functional group is not particularly limited, but a method of treating with a functionalizing reagent (silane coupling agent) is simple and preferable.
[0056]
Specific examples of the functionalizing reagent include, for example, chlorosilanes having an epoxy group, chlorosilanes having a carboxyl group, chlorosilanes having a mercapto group, alkoxysilanes having an amino group, alkoxysilanes having an epoxy group, and the like. Among them, chlorosilanes having an epoxy group such as 3-glycidyloxypropyldimethylchlorosilane, β- (3,4-epoxycyclohexyl) ethyldimethylchlorosilane, 3-glycidyloxypropyltrichlorosilane, and 3-aminopropyltriethoxysilane Alkoxysilanes having an amino group such as N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-glycidyloxy B pills methyl diethoxy silane, 3-glycidyloxypropyltrimethoxysilane, alkoxysilanes having a beta-(3,4-epoxycyclohexyl) ethyltrimethoxysilane and epoxy groups are preferred. The method of contacting these functionalizing reagents with the layered silicate is not particularly limited, but it is usually preferable to carry out the mixing without solvent or in a polar solvent.
[0057]
Specific examples of the layered silicate used in the present invention include smectite-based clay minerals such as montmorillonite, hectorite, fluorine hectorite, saponite, beidellite, subchinsite, Li-type fluorine teniolite, Na-type fluorine teniolite, and Na-type Examples include swellable synthetic mica such as silicon fluorine mica and Li-type tetrasilicon fluorine mica, vermiculite, fluorine vermiculite, halloysite, and the like, which may be natural or synthesized. Among them, smectite-based clay minerals such as montmorillonite and hectorite, and swellable synthetic mica such as Li-type fluorine teniolite, Na-type fluorine teniolite, and Na-type tetrasilicon fluorine mica are preferable.
[0058]
There is no particular limitation on the quaternary onium cation inserted between the layers of the modified layered silicate used in the present invention. Specific examples that are preferably used include trimethyloctylammonium, trimethyldecylammonium, trimethyldodecylammonium and trimethyltetramethylammonium. Dimethyldialkyl such as decylammonium, trimethylhexadecylammonium, trimethyloctadecylammonium, etc. Ammonium and the like.
[0059]
When a layered silicate is used as the component (F) in the polyester resin composition of the present invention, its addition amount is 0.1 to 15 parts by weight based on 100 parts by weight of the total of the components (A) and (B). It is preferably from 0.3 to 12 parts by weight, particularly preferably from 0.5 to 10 parts by weight. If the amount of the layered silicate as the component (F) is less than 0.1 part by weight, the effect of preventing dripping during combustion is insufficient, and if it is more than 15 parts by weight, fluidity and mechanical properties are extremely reduced. The layered silicate may be used alone or in combination of two or more.
[0060]
It is also preferable to use silicone oil as the component (F) anti-dripping agent, and the silicone oil is a compound having a dimethylpolysiloxane skeleton represented by the following general formula (7), and a part of the terminal or side chain or All functionalized with amino modification, epoxy modification, carboxyl modification, carbinol modification, methacryl modification, mercapto modification, phenol modification, polyether modification, methylstyryl modification, alkyl modification, higher fatty acid ester modification, higher alkoxy modification, fluorine modification May be used.
[0061]
Embedded image

[0062]
(F) The viscosity of the silicone oil used as an anti-drip agent at 25 ° C. is preferably from 1,000 to 30,000 (cs.), More preferably from 2,000 to 25,000 (cs.), Particularly preferably from 3,000 to 20,000 (cs.). If it is less than 1000 (cs.), The effect of preventing dripping during combustion is insufficient, and the flame retardancy is greatly reduced. If it is more than 30,000 (cs.), The fluidity of the composition is significantly reduced due to the thickening effect. Component (F) When silicone oil is used as an anti-dripping agent, the amount is 0.001 to 10 parts by weight, preferably 0.1 to 10 parts by weight, based on 100 parts by weight of the total of components (A) and (B). 005 to 8 parts by weight, particularly preferably 0.01 to 5.0 parts by weight. If the silicone oil as the component (F) is less than 0.001 part by weight, the effect of preventing dripping is insufficient, and if it is more than 10 parts by weight, the fluidity and mechanical properties are significantly reduced.
[0063]
The composition of the present invention preferably contains (G) melamine cyanurate. (G) Melamine cyanurate is a substantially equimolar reaction product of cyanuric acid and melamine, for example, an aqueous solution of cyanuric acid and an aqueous solution of melamine are mixed and reacted under stirring at a temperature of 90 to 100 ° C. It can be obtained by filtering the precipitate. The melamine cyanurate has a particle size of 0.01 to 1000 microns, preferably 0.01 to 500 microns. Some of the amino groups or hydroxyl groups of melamine cyanurate may be substituted with other substituents. The amount of melamine cyanurate is 0 to 45 parts by weight, preferably 3 to 40 parts by weight, particularly preferably 5 to 30 parts by weight, based on 100 parts by weight of the total of components (A) and (B). If the amount of melamine cyanurate is more than 45 parts by weight, the toughness and ductility are reduced, and bleed-out and plate-out are caused.
The ratio of the component (D) to the component (G) melamine cyanurate is not particularly limited, but is usually 1: 9 to 9: 1, especially 2: 8 to 8: 2, particularly preferably 2.5: 2. 7.5-7.5 to 2.5.
[0064]
The polyester resin composition of the present invention preferably contains (H) a metal borate. The component (H) metal borate used in the present invention is preferably stable under ordinary processing conditions and free from volatile components. (H) Examples of the metal borate include alkali metal salts of boric acid (eg, sodium tetraborate, potassium metaborate, etc.) and alkaline earth metal salts (eg, calcium borate, magnesium orthoborate, barium orthoborate, zinc borate, etc.). Can be Among these, zinc borate is preferable. Zinc borate is generally 2ZnO.3B ₂ O ₃ ・ XH ₂ O (x = 3.3 to 3.7). The hydrated zinc borate is preferably 2ZnO.3B ₂ O ₃ ・ 3.5H ₂ It has the formula of O and is stable up to 260 ° C. or higher.
The amount of the metal borate is 0 to 50 parts by weight, preferably 2 to 45 parts by weight, particularly preferably 3 to 40 parts by weight, based on 100 parts by weight of the total of the components (A) and (B). (H) If the compounding amount of the metal borate exceeds 50 parts by weight, the mechanical properties tend to deteriorate.
[0065]
The polybutylene terephthalate resin composition of the present invention may contain, if necessary, conventional additives and the like in addition to the components (A) to (H). There are no particular restrictions on the additives to be blended.For example, additives such as antioxidants, stabilizers such as heat stabilizers, lubricants, mold release agents, catalyst deactivators, crystal nucleating agents, and crystallization accelerators are It can be added during or after the polymerization of butylene terephthalate. Further, an epoxy compound, carbodiimide, oxazoline or the like can be added to further improve the hydrolysis resistance. Furthermore, in order to impart desired performance to polybutylene terephthalate, stabilizers such as ultraviolet absorbers, weather stabilizers, coloring agents such as dyes and pigments, antistatic agents, foaming agents, plasticizers, and impact modifiers And the like.
In the polybutylene terephthalate resin composition of the present invention, if necessary, polyethylene, polypropylene, acrylic resin, polycarbonate, polyamide, polyphenylene sulfide resin, polyethylene terephthalate, liquid crystal polyester resin, polyacetal, thermoplastic resin such as polyphenylene oxide, A molded article can be obtained by blending a thermosetting resin such as an epoxy resin, a phenol resin, a melamine resin, and a silicone resin. One of these thermoplastic resins and thermosetting resins can be used alone, or two or more can be used in combination.
[0066]
The method for producing the flame-retardant polyester resin composition of the present invention is not particularly limited, and can be easily achieved by mixing the components by a known method. For example, a method of dry blending using a blender or a mixer, a method of melt-mixing using an extruder, and the like are mentioned. The method is suitable. Specifically, a method in which each component is melt-kneaded all at once, a method in which a specific component is melt-mixed first, and the like are mentioned. Among them, from the viewpoint of mechanical properties, component (A) polyester resin and component (B) A production method in which PPE and the three components of the component (C) compatibilizer are first melt-mixed, and then the remaining components are mixed, and particularly, the components (A), (B), (C) and ( B) A production method in which the four components of the solvent are first melt-mixed and then the remaining components are mixed. Examples of the solvent include xylene, toluene, trichlorobenzene, chloroform, α-chloronaphthalene, and the like.From the viewpoint of suppression of corrosive gas generation and ease of solvent removal, xylene and toluene are preferred, and xylene is particularly preferred. Used.
[0067]
The mixing method of each component is not particularly limited, and a batch blending method in which components are collectively melt-kneaded using a twin screw extruder, and a split blending in which a reinforcing filler or the like is added from another supply port. And the like.
[0068]
There is no particular limitation on the molding method of the polybutylene terephthalate molded product of the present invention, and molding methods generally used for thermoplastic resins, that is, molding methods such as injection molding, hollow molding, extrusion molding, and press molding are applied. be able to.
[0069]
The flame-retardant polybutylene terephthalate resin composition of the present invention is excellent in flame retardancy, mechanical properties, hydrolysis resistance, etc., has no mold corrosion due to generation of corrosive gas, and further has low specific gravity and excellent fluidity. It can be suitably used for molded articles having a thin or complicated shape. Therefore, the composition of the present invention is suitable as a material for producing electric equipment, electronic equipment or parts thereof.
[0070]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples unless it exceeds the gist of the present invention.
In Examples and Comparative Examples, measurement of physical properties of polybutylene terephthalate and evaluation of the resin composition of the present invention were performed by the following methods.
(1) terminal carboxyl group content;
0.1 g of polybutylene terephthalate was dissolved in 3 ml of benzyl alcohol, and titrated using a 0.1 mol / liter-benzyl alcohol solution of sodium hydroxide.
[0071]
(2) Temperature drop crystallization temperature;
Using a differential scanning calorimeter [Perkin Elmer, Model 1B], polybutylene terephthalate was heated from room temperature to 300 ° C. at a heating rate of 20 ° C./min, and then cooled to 80 ° C. at a cooling rate of 20 ° C./min. In this case, the temperature of the exothermic peak was measured, and the measured temperature was defined as the temperature drop crystallization temperature.
[0072]
(3) Amount of residual tetrahydrofuran;
5 g of polybutylene terephthalate pellets were immersed in 10 g of water, treated at 120 ° C. for 6 hours under pressure, and tetrahydrofuran eluted in water was quantified by gas chromatography.
[0073]
(4) intrinsic viscosity;
Using an Ubbelohde viscometer and a mixed solvent of phenol / 1,1,2,2-tetrachloroethane (weight ratio 1/1) at 30 ° C., concentrations of 1.0 g / dl, 0.6 g / dl and 0.3 g. The viscosity of the / dl solution was measured and the viscosity number was extrapolated to a concentration of 0.
[0074]
(5) flame retardancy;
The test pieces manufactured in the examples were tested according to the test method shown in UL-94 “Combustion Test for Material Classification” (hereinafter, UL-94) of Underwriters Laboratories, Inc. Based on the results of five 32-inch test pieces, the test pieces were rated as one of V-0, V-1 and V-2 of the UL-94 standard. The grading criteria for each V for UL-94 are as follows. (I) V-0: The average flame holding time after removing the ignition flame is 5 seconds or less, and all the test pieces do not drop fine flames that ignite absorbent cotton.
(Ii) V-1: The average flame holding time after removing the ignition flame is 25 seconds or less, and all the test pieces do not drop fine flames that ignite absorbent cotton.
(Iii) V-2: The average flame holding time after removing the ignition flame is 25 seconds or less, and the cotton wool is ignited from the fine-grained flame dropped from these test pieces.
[0075]
(6) generated gas;
After putting 5 g of the resin composition pellets into a 26 ml glass vial and heating at 150 ° C. for 2 hours, a sample is collected from the gas phase using a microsyringe and analyzed by gas chromatography. The peak area of the chromatogram was determined, and the weight of tetrahydrofuran corresponding to the area was expressed as a ratio (ppm) to the resin.
[0076]
(7) hydrolysis resistance;
The ASTM No. 1 dumbbell piece is subjected to moist heat treatment at 121 ° C. in saturated steam at 203 kPa for 60 hours for non-reinforced and 100 hours for glass fiber (GF) reinforced, respectively. The tensile strength before and after the treatment was measured according to ASTM D-638, and the strength retention was determined according to the following equation. The tensile strength after the wet heat treatment in the following formula is a value after the treatment for 60 hours in the case of non-strengthening and a value after the treatment for 100 hours in the case of GF reinforcement.
[0077]
(Equation 1)
Strength retention (%) = (tensile strength after wet heat treatment / tensile strength before treatment) × 100
[0078]
The components other than the polybutylene terephthalate used in the examples and comparative examples are as follows.
(A) PPE: polyphenylene ether (manufactured by Mitsubishi Engineering-Plastics Corporation, trade name Iupiace, intrinsic viscosity 0.36).
(B) PC: polycarbonate (manufactured by Mitsubishi Engineering-Plastics Corporation, trade name NOVAREX, intrinsic viscosity 0.36).
(C) Phosphate ester: a phosphate ester represented by the following formula (8).
[0079]
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[0080]
(D) Melamine cyanurate: manufactured by Mitsubishi Chemical Corporation.
(E) GF: glass fiber (manufactured by NEC Corporation, epoxysilane treated product, 3 mm chopped strand, brand name: T-187).
(F) PTFE: polytetrafluoroethylene (manufactured by Daikin Industries, Ltd., polytetrafluoroethylene resin, polyfluorocarbon F201).
(G) Zinc borate: manufactured by Borax Japan Co., Ltd.
[0081]
Example 1
Continuous polymerization was performed according to the system diagram shown in FIG. Both raw materials were supplied to a slurry preparation tank in a ratio of 1.8 mol of 1,4-butanediol to 1.0 mol of terephthalic acid, and 2,972 parts by weight of a slurry prepared by mixing with a stirrer (terephthalic acid 9 0.06 mol parts, 16.31 mol parts of 1,4-butanediol) were continuously adjusted to a temperature of 230 ° C. and a pressure of 101 kPa by a gear pump, and transferred to the first esterification reaction tank, and tetrabutyl titanate 3 was added. .14 parts by weight were supplied, and an esterification reaction was carried out with stirring for 2 hours under stirring to obtain an oligomer.
The oligomer was transferred from the first esterification reaction tank to a second esterification reaction tank adjusted to a temperature of 240 ° C. and a pressure of 101 kPa, and the esterification reaction was further advanced with stirring for 1 hour at a residence time.
The oligomer is transferred from the second esterification reaction tank to the first polycondensation reaction tank adjusted to a temperature of 250 ° C. and a pressure of 6.67 kPa, and subjected to a polycondensation reaction with stirring at a residence time of 2 hours to obtain a prepolymer. Was.
From the first polycondensation reaction tank, the prepolymer was transferred to a second double condensation reaction tank adjusted to a temperature of 250 ° C. and a pressure of 133 Pa, and the polycondensation reaction was further advanced with stirring for 3 hours, thereby polymerizing the polymer. Obtained. This polymer was withdrawn from the second double condensation tank, transferred to a die, drawn out in a strand shape, and cut with a pelletizer to obtain a polybutylene terephthalate in a beret shape.
[0082]
The amount of terminal carboxyl groups of the obtained polybutylene terephthalate was 20 eq / t, the cooling crystallization temperature was 178 ° C., the amount of residual tetrahydrofuran was 180 ppm (weight ratio), and the intrinsic viscosity was 0.85 dl / g.
70 parts by weight of this polybutylene terephthalate, 30 parts by weight of PPE, 2 parts by weight of PC, 15 parts by weight of a phosphate ester compound, 15 parts by weight of melamine cyanurate, 4 parts by weight of zinc borate, 59 parts by weight of GF, and 1 part by weight of polytetrafluoroethylene This was melt-kneaded at a barrel temperature of 270 ° C. using a 30 mm vent-type twin-screw extruder (manufactured by Nippon Steel Works Co., Ltd., twin-screw extruder TEX30) and extruded into strands. Pelletized. A test piece was formed using the obtained pellet. The UL-94 combustion test piece was manufactured by using an injection molding machine (manufactured by Nippon Steel Works Co., Ltd., model J28SA) and a mold for the UL-94 combustion test piece at a cylinder temperature of 270 ° C and a mold temperature of 80 ° C. And ASTM No. 1 dumbbell pieces were each molded at a cylinder temperature of 255 ° C. and a mold temperature of 80 ° C. using an injection molding machine (Model SG-75, manufactured by Sumitomo Heavy Industries, Ltd.) and evaluated.
The tensile strength before the wet heat treatment was 125 MPa, the tensile strength after the wet heat treatment was 69 MPa, and the strength retention was 55%. Further, the flame retardancy was V-0, and the amount of generated gas was 16 ppm. The results are shown in Table 1.
[0083]
Examples 2 and 3 and Comparative Examples 1 and 2
A resin composition was produced according to the formulation shown in Table 1, and evaluated in the same manner as in Example 1. The results are shown in Table 1.
[0084]
Comparative Example 3
The polymerization reaction was performed using a batch type apparatus. A total of 3,226 parts by weight of 1.8 mol of 1,4-butanediol is supplied to the transesterification reactor with respect to 1.0 mol of dimethyl terephthalate, and 3.14 parts by weight of tetrabutyl titanate is added. Then, transesterification was performed at a temperature of 210 ° C. and a pressure of 101 kPa for 3 hours to obtain an oligomer. Subsequently, the oligomer was transferred to a polycondensation reaction tank, and a polycondensation reaction was allowed to proceed at a temperature of 250 ° C. and a pressure of 133 Pa for 3 hours with stirring to obtain a polymer. Next, the resultant was drawn out into a strand by applying a nitrogen pressure, and cut with a pelletizer to obtain polybutylene terephthalate in a pellet form.
The amount of terminal carboxyl groups of the obtained polybutylene terephthalate was 41 eq / t, the cooling crystallization temperature was 170 ° C., the amount of residual tetrahydrofuran was 680 ppm (weight ratio), and the intrinsic viscosity was 0.85 dl / g.
[0085]
70 parts by weight of the obtained polybutylene terephthalate, 30 parts by weight of PPE, 2 parts by weight of PC, 15 parts by weight of a phosphate ester compound, 15 parts by weight of melamine cyanurate, 4 parts by weight of zinc borate, 59 parts by weight of GF, 1 part by weight of polytetrafluoroethylene This was melt-kneaded at a barrel temperature of 270 ° C. using a 30 mm vent type twin-screw extruder (manufactured by Nippon Steel Works, Ltd., twin-screw extruder Lab TEX30) and extruded into strands. Pelletized with a cutter. Using the obtained pellets, an injection molding machine (manufactured by Nippon Steel Works Co., Ltd., model J28SA) and a mold for a UL94 combustion test piece were used. Was molded and evaluated.
The tensile strength before the wet heat treatment was 124 MPa, the tensile strength after the wet heat treatment was 35 MPa, and the strength retention was 28%. Further, the flame retardancy was V-0 and the amount of generated gas was 27 ppm. The results are shown in Table 1.
[0086]
Comparative Examples 4 and 5
A resin composition was produced according to the formulation shown in Table 1 and evaluated in the same manner as in Example 1. The results are shown in Table 1.
[0087]
[Table 1]

[0088]
[Table 2]

[0089]
As is evident from Table 1, a terephthalic acid and 1,4-butanediol obtained by continuous polycondensation and having a terminal carboxyl group content, a temperature-reducing crystallization temperature and a residual tetrahydrofuran content defined in the present invention. Examples 1 and 2, which are flame-retardant polybutylene terephthalate compositions using butylene terephthalate, are obtained by batch-wise polycondensation of dimethyl terephthalate and 1,4-butanediol, and are outside the specified range of the present invention. Although the flame retardancy is the same as the flame retardant polybutylene terephthalate composition using polybutylene terephthalate having a terminal carboxyl group content, a cooling crystallization temperature and a residual tetrahydrofuran content (Comparative Examples 3 and 4), Excellent hydrolytic properties. Also, since the amount of generated gas is small, it is considered that the effect of preventing corrosion of metal contacts is large.
When the PPE is less than the specified amount of the present invention (Comparative Example 1), the flame retardancy is inferior. On the other hand, when the phosphate ester is larger than the specified amount of the present invention (Comparative Example 2), the flame retardancy is V-0. However, the tensile strength and the hydrolysis resistance decrease.
[0090]
【The invention's effect】
The polybutylene terephthalate of the present invention has a short molding cycle, is excellent in productivity, does not corrode electrical contacts, has high stability especially against hydrolysis, and is suitably used for electric and electronic parts which are severe in contact corrosion. be able to.
[Brief description of the drawings]
FIG. 1 is a process flow diagram of one embodiment of an apparatus for producing polybutylene terephthalate of the present invention.
[Explanation of symbols]
1 Slurry preparation tank
2 First esterification reaction tank
3 Second esterification reaction tank
4 First polycondensation reaction tank
5 Double condensation reaction tank
6 pelletizer

Claims (10)

(A) A polymer having a terminal carboxyl group content of 30 eq / t or less and a temperature-reducing crystallization temperature of 175 ° C. or more, or a temperature-reducing crystallization temperature of 175 ° C. or more and a residual tetrahydrofuran content of 300 ppm or less. (C) 0.05 to 10 parts by weight of a compatibilizer, and (D) phosphate ester based on 100 parts by weight of a mixed resin composed of 95 to 50 parts by weight of butylene terephthalate and 5 to 50 parts by weight of (B) a polyphenylene ether resin. Or 2 to 45 parts by weight of at least one compound selected from phosphonitrile, (E) 0 to 150 parts by weight of a reinforcing filler, (F) 0.001 to 15 parts by weight of an anti-dripping agent, (G) melamine cyanurate A flame-retardant polybutylene terephthalate resin composition comprising 0 to 45 parts by weight and (H) 0 to 50 parts by weight of a metal borate. The flame retardant polybutylene terephthalate resin composition according to claim 1, wherein the compatibilizer (C) is a phosphite triester or a polycarbonate resin. 3. The flame-retardant polybutylene terephthalate resin composition according to claim 1, wherein the (D) phosphate compound is selected from phosphate compounds represented by the following general formula (1). 4.

(Wherein, R ^{1 to} R ⁸ are a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, m is 0 or an integer of 1 to 4. R ⁹ is a p-phenylene group, an m-phenylene group, A 4,4′-biphenylene group or a divalent group selected from the following):

4. The composition according to claim 1, wherein the component (F) contains 0.1 to 15 parts by weight of a layered silicate as a dripping inhibitor, based on 100 parts by weight of the total of (A) and (B). 5. The flame-retardant polybutylene terephthalate resin composition according to any one of the above. 4. The composition according to claim 1, wherein (F) the anti-dripping agent contains 0.001 to 15 parts by weight of a fluororesin based on 100 parts by weight of the total of (A) and (B). 5. 3. The flame-retardant polybutylene terephthalate resin composition according to item 1. The flame-retardant polybutylene terephthalate resin composition according to any one of claims 1 to 5, wherein the (H) metal borate is zinc borate. The polybutylene terephthalate (A) has a terminal carboxyl group content of 30 eq / t or less, a temperature-reducing crystallization temperature of 175 ° C. or more, and a residual tetrahydrofuran content of 300 ppm or less. The flame-retardant polybutylene terephthalate resin composition according to any one of the above. The intrinsic viscosity of the polybutylene terephthalate (A) is 0.5 to 1.5 dl / g when measured at 30 ° C. using a mixed solvent of phenol / tetrachloroethane (weight ratio 1/1). The flame-retardant polybutylene terephthalate resin composition according to claim 1. The flame retardancy according to any one of claims 1 to 8, wherein the (A) polybutylene terephthalate is a polybutylene terephthalate obtained by continuously polymerizing terephthalic acid and 1,4-butanediol as main raw materials. Polybutylene terephthalate resin composition. A molded article obtained by molding the flame-retardant polybutylene terephthalate resin composition according to claim 1.

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