JP3617578B2 - Weather-resistant polycarbonate sheet and process for producing the same - Google Patents

Description

【００２２】
（式中、Ｒ_１、Ｒ_２、Ｒ_３、Ｒ_４は、各々独立に水素、炭素数１〜１０のアルキル基、炭素数１〜１０のアルコキシ基、環構成炭素数５〜１０のシクロアルキル基、環構成炭素数５〜１０の炭素環式芳香族基、炭素数６〜１０の炭素環式アラルキル基を表す。ｋは３〜１１の整数を表し、Ｒ_５およびＲ_６は、各Ｘについて個々に選択され、お互いに独立に、水素または炭素数１〜６のアルキル基を表し、Ｘは炭素を表す。また、Ｒ_１、Ｒ_２、Ｒ_３、Ｒ_４、Ｒ_５、Ｒ_６において、一つ以上の水素原子が反応に悪影響を及ぼさない範囲で他の置換基、例えばハロゲン原子、炭素数１〜１０のアルキル基、炭素数１〜１０のアルコキシ基、フェニル基、フェノキシ基、ビニル基、シアノ基、エステル基、アミド基、ニトロ基等によって置換されたものであっても良い。）
このような２価の芳香族基Ａｒとしては、例えば、下記化２で示されるものが挙げられる。
【００２３】
【化２】

【００２４】
（式中、Ｒ_７、Ｒ_８は、各々独立に水素原子、ハロゲン原子、炭素数１〜１０のアルキル基、炭素数１〜１０のアルコキシ基、環構成炭素数５〜１０のシクロアルキル基またはフェニル基であって、ｍおよびｎは１〜４の整数で、ｍが２〜４の場合には各Ｒ_７はそれぞれ同一でも異なるものであってもよいし、ｎが２〜４の場合には各Ｒ_８はそれぞれ同一でも異なるものであってもよい。）
さらに、２価の芳香族基Ａｒは、−Ａｒ_１−Ｚ−Ａｒ_２−で示されるものであっても良い。
【００２５】
（式中、Ａｒ_１、Ａｒ_２は前述の通りで、Ｚは単結合又は−Ｏ−、−ＣＯ−、−Ｓ−、−ＳＯ２ −、−ＳＯ−、−ＣＯＯ−、−ＣＯＮ（Ｒ_１）−などの２価の基を表す。ただし、Ｒ_１は前述のとおりである。）
このような２価の芳香族基Ａｒとしては、例えば、下記化３で示されるものが挙げられる。
【００２６】
【化３】

【００２７】
（式中、Ｒ_７、Ｒ_８、ｍおよびｎは、前述のとおりである。）
本発明で用いられる芳香族ジヒドロキシ化合物は、単独で用いてもよく、２種以上を組み合わせて用いても良い。芳香族ジヒドロキシ化合物の代表的な例としてはビスフェノールＡが挙げられ、特にビスフェノールＡを８５％以上用いることが好ましい。また、これら芳香族ジヒドロキシ化合物は、塩素原子とアルカリまたはアルカリ土類金属の含有量が少ない方が好ましく、出来れば実質的に含有していないことが好ましい。
【００２８】
本発明で用いられる炭酸ジエステルは、下記化４で表される。
【００２９】
【化４】

【００３０】
（式中、Ａｒ_３、Ａｒ_４はそれぞれ１価の芳香族基を表す。）
Ａｒ_３及びＡｒ_４は、１価の炭素環式又は複素環式芳香族基を表すが、このＡｒ_３、Ａｒ_４において、１つ以上の水素原子が、反応に悪影響を及ぼさない他の置換基、例えば、ハロゲン原子、炭素数１〜１０のアルキル基、炭素数１〜１０のアルコキシ基、フェニル基、フェノキシ基、ビニル基、シアノ基、エステル基、アミド基、ニトロ基などによって置換されたものであっても良い。Ａｒ_３、Ａｒ_４は同じものであっても良いし、異なるものであっても良い。
【００３１】
１価の芳香族基Ａｒ_３及びＡｒ_４の代表例としては、フェニル基、ナフチル基、ビフェニル基、ピリジル基を挙げる事ができる。これらは、上述の１種以上の置換基で置換されたものでも良い。
好ましいＡｒ_３及びＡｒ_４としては、それぞれ例えば、下記化５などが挙げられる。
【００３２】
【化５】

【００３３】
炭酸ジエステルの代表的な例としては、下記化６で示される置換または非置換のジフェニルカーボネート類を挙げる事ができる。
【００３４】
【化６】

【００３５】
（式中、Ｒ_９及びＲ_１０は、各々独立に水素原子、炭素数１〜１０を有するアルキル基、炭素数１〜１０を有するアルコキシ基、環構成炭素数５〜１０のシクロアルキル基又はフェニル基を示し、ｐ及びｑは１〜５の整数で、ｐが２以上の場合には、各Ｒ９ はそれぞれ異なるものであっても良いし、ｑが２以上の場合には、各Ｒ１０は、それぞれ異なるものであっても良い。）
このジフェニルカーボネート類の中でも、非置換のジフェニルカーボネートや、ジトリルカーボネート、ジ−ｔ−ブチルフェニルカーボネートのような低級アルキル置換ジフェニルカーボネートなどの対称型ジアリールカーボネートが好ましいが、特にもっとも簡単な構造のジアリールカーボネートであるジフェニルカーボネートが好適である。
【００３６】
これらの炭酸ジエステル類は単独で用いても良いし、２種以上を組み合わせて用いても良い。また、これらジアリールカーボネートは、塩素原子とアルカリまたはアルカリ土類金属の含有量が少ない方が好ましく、出来れば実質的に含有していないことが好ましい。
芳香族ジヒドロキシ化合物と炭酸ジエステルとの使用割合（仕込比率）は、用いられる芳香族ジヒドロキシ化合物とジアリールカーボネートの種類や、重合温度その他の重合条件及び得ようとするポリカーボネートの分子量や末端比率によって異なり、特に限定されない。ジアリールカーボネートは芳香族ジヒドロキシ化合物１モルに対して、通常０．９〜２．５モル、好ましくは０．９５〜２．０モル、より好ましくは０．９８〜１．５モルの割合で用いらる。ヒドロキシ末端と非ヒドロキシ末端の比率は、０／１００〜１００／０の範囲でコントロールされる。
【００３７】
また、本発明においては、本発明の目的を損なわない範囲で、分岐構造を導入するための芳香族多価ヒドロキシ化合物を少量併用してもよいし、末端変換や分子量調節のために芳香族モノヒドロキシ化合物を併用してもよい。
本発明において、エステル交換法とは、上記化合物を触媒の存在もしくは非存在下で、減圧下もしくは／及び不活性ガスフロー下で加熱しながら溶融状態でエステル交換反応にて重縮合する方法をいい、その重合方法、装置等には制限はない。例えば、攪拌槽型反応器、薄膜反応器、遠心式薄膜蒸発反応器、表面更新型二軸混練反応器、二軸横型攪拌反応器、濡れ壁式反応器、自由落下させながら重合する多孔板型反応器、ワイヤーに沿わせて落下させながら重合するワイヤー付き多孔板型反応器等を用い、これらを単独もしくは組み合わせることで容易に製造できる。また、溶融状態でエステル交換反応を行いプレポリマーを製造した後、固相状態で減圧下もしくは／及び不活性ガスフロー下で重合度を高める固相重合法でも製造できる。また、これら反応器の材質に特に制限はなく、通常ステンレススチールやニッケル、グラスライニング等から選ばれる。
【００３８】
本発明で用いられるポリカーボネートは、上記のようなエステル交換法で製造されればよく、その製造法は特に限定されない。 通常、ポリカーボネートを製造するためのエステル交換の反応温度は、通常５０〜３５０℃、好ましくは１００〜３００℃の温度の範囲で選ばれいる。一般に、上記範囲より高い温度では、得られるポリカーボネートの着色が大きく且つ熱安定性にも劣る傾向にあり、上記範囲より低い温度では、重合反応が遅く実用的でないことが知られている。本発明においては、上記エステル交換法において、製造中のポリカーボネートの温度と滞留時間とを（１）式を満足する特定の範囲で制御することにより、ポリカーボネートを製造することが好ましい。温度と滞留時間との関係が上記範囲より大きいと、引張伸度やＩＺＯＤ衝撃強度等の機械的物性が低下し好ましくなく、上記範囲より小さいと、成形流動性が低下し好ましくない。
【００３９】

Ｔｉ：ｉ工程におけるポリカーボネートの平均温度（℃）
Ｈｉ：ｉ工程での平均滞留時間（ｈｒ）
ｋｉ：（２）式で示されるＴｉ温度での係数
ｋｉ＝１／ａＴｉ^−ｂ （２）
但し、Ｔｉ＜２４０℃の時
ａ＝１．６００４６×１０^５
ｂ＝０．４７２
但し、２４０℃≦Ｔｉ＜２６０℃の時
ａ＝４×１０^４９
ｂ＝１９．１０７
但し、２６０℃≦Ｔｉの時
ａ＝１×１０^１２２
ｂ＝４９．０８２
エステル交換法によるポリカーボネートの製造においては、温度や滞留時間及び反応圧力を段階的に変えるのが一般的であり、（１）式は、各段階でのｋ×Ｔ×Ｈの総和を示している。例えば、芳香族ジヒドロキシ化合物と炭酸ジエステルの溶解混合槽、攪拌槽型反応器、遠心式薄膜蒸発反応器及び表面更新型二軸混練反応器を連結して連続重合した場合のΣ（ｋｉ×Ｔｉ×Ｈｉ）は、（溶解混合槽でのｋ×Ｔ×Ｈ）＋（溶解混合槽から攪拌槽型反応器までの配管でのｋ×Ｔ×Ｈ）＋（攪拌槽型反応器でのｋ×Ｔ×Ｈ）＋（攪拌槽型反応器から遠心式薄膜蒸発反応器までの配管のｋ×Ｔ×Ｈ）＋（遠心式薄膜蒸発反応器でのｋ×Ｔ×Ｈ）＋（遠心式薄膜蒸発反応器から表面更新型二軸混練反応器までの配管のｋ×Ｔ×Ｈ）＋（表面更新型二軸混練反応器でのｋ×Ｔ×Ｈ）＋（表面更新型二軸混練反応器から抜き出しノズルまでの配管のｋ×Ｔ×Ｈ）となり、配管までを含めた全ての段階での総和を示している。この場合、ｉ工程とは、各混合槽や反応器及びそれを連結する配管の各段階や工程をいう。反応器と反応器を結ぶ配管の途中に加熱器がある場合は、反応器と加熱器までの配管、加熱器、加熱器と反応器までの配管をそれぞれｉ工程とする。ポリカーボネートの平均温度は、ｉ工程内での温度の平均値をいい、温度が明らかに数段階に分かれていれば、その各段階を分割して、各ｉ工程として、該段階での平均温度を用いてもよい。平均滞留時間は各ｉ工程でのポリカーボネートの保有量／１時間当たりの通過量もしくは抜き出し量で計算される。
【００４０】
また、反応圧力は、溶融重合中のポリカーボネートのの分子量によっても異なり、数平均分子量が１０００以下の範囲では、５０ｍｍＨｇ〜常圧の範囲が一般に用いられ、数平均分子量が１０００〜２０００の範囲では、３ｍｍＨｇ〜８０ｍｍＨｇの範囲が、数平均分子量が２０００以上の範囲では、１０ｍｍＨｇ以下、特に５ｍｍＨｇ以下が用いられる。
【００４１】
また、エステル交換法による重合は、触媒を加えずに実施する事ができるが、重合速度を高めるため、必要に応じて触媒の存在下で行われる。重合触媒としては、この分野で用いられているものであれば特に制限はないが、水酸化リチウム、水酸化ナトリウム、水酸化カリウム、水酸化カルシウムなどのアルカリ金属及びアルカリ土類金属の水酸化物類；水素化アルミニウムリチウム、水素化ホウ素ナトリウム、水素化ホウ素テトラメチルアンモニウムなどのホウ素やアルミニウムの水素化物のアルカリ金属塩、アルカリ土類金属塩、第四級アンモニウム塩類；水素化リチウム、水素化ナトリウム、水素化カルシウムなどのアルカリ金属及びアルカリ土類金属の水素化合物類；リチウムメトキシド、ナトリウムエトキシド、カルシウムメトキシドなどのアルカリ金属及びアルカリ土類金属のアルコキシド類；リチウムフェノキシド、ナトリウムフェノキシド、マグネシウムフェノキシド、ＬｉＯ−Ａｒ−ＯＬｉ、ＮａＯ−Ａｒ−ＯＮａ（Ａｒはアリール基）などのアルカリ金属及びアルカリ土類金属のアリーロキシド類；酢酸リチウム、酢酸カルシウム、安息香酸ナトリウムなどのアルカリ金属及びアルカリ土類金属の有機酸塩類；酸化亜鉛、酢酸亜鉛、亜鉛フェノキシドなどの亜鉛化合物類；酸化ホウ素、ホウ酸、ホウ酸ナトリウム、ホウ酸トリメチル、ホウ酸トリブチル、ホウ酸トリフェニル、（Ｒ_１Ｒ_２Ｒ_３Ｒ_４）ＮＢ（Ｒ_１Ｒ_２Ｒ_３Ｒ_４）または（Ｒ_１Ｒ_２Ｒ_３Ｒ_４）ＰＢ（Ｒ_１Ｒ_２Ｒ_３Ｒ_４）で表されるアンモニウムボレート類またははホスホニウムボレート類（Ｒ_１、Ｒ_２、Ｒ_３、Ｒ_４は前記化３の説明通り）などのホウ素の化合物類；酸化ケイ素、ケイ酸ナトリウム、テトラアルキルケイ素、テトラアリールケイ素、ジフェニル−エチル−エトキシケイ素などのケイ素の化合物類；酸化ゲルマニウム、四塩化ゲルマニウム、ゲルマニウムエトキシド、ゲルマニウムフェノキシドなどのゲルマニウムの化合物類；酸化スズ、ジアルキルスズオキシド、ジアルキルスズカルボキシレート、酢酸スズ、エチルスズトリブトキシドなどのアルコキシ基またはアリーロキシ基と結合したスズ化合物、有機スズ化合物などのスズの化合物類；酸化鉛、酢酸鉛、炭酸鉛、塩基性炭酸塩、鉛及び有機鉛のアルコキシドまたはアリーロキシドなどの鉛の化合物；第四級アンモニウム塩、第四級ホスホニウム塩、第四級アルソニウム塩などのオニウム化合物類；酸化アンチモン、酢酸アンチモンなどのアンチモンの化合物類；酢酸マンガン、炭酸マンガン、ホウ酸マンガンなどのマンガンの化合物類；酸化チタン、チタンのアルコキシドまたはアリーロキシドなどのチタンの化合物類；酢酸ジルコニウム、酸化ジルコニウム、ジルコニウムのアルコキシド又はアリーロキシド、ジルコニウムアセチルアセトンなどのジルコニウムの化合物類などの触媒を挙げる事ができる。
【００４２】
触媒を用いる場合、これらの触媒は１種だけで用いても良いし、２種以上を組み合わせて用いても良い。また、これらの触媒の使用量は、原料の芳香族ジヒドロキシ化合物に対して、通常１０^−８〜１重量％、好ましくは１０^−７〜１０^−１重量％の範囲で選ばれる。
本発明で用いられるポリカーボネートの分子量は特に限定されないが、一般に重量平均分子量で通常１０００〜３０００００の範囲であり、好ましくは５０００〜１０００００の範囲であり、特に好ましくは１２０００〜８００００の範囲にある。また、末端構造も特に限定されない。
【００４３】
本発明で用いられるポリカーボネートは、完全加水分解して、逆相液体クロマトグラフィーで測定したときに、リテンションタイムが用いた芳香族ジヒドロキシ化合物より後にある化合物、即ち少量の適度な異種結合と推定される結合を有しているために、色調や機械的物性に優れ、かつホスゲン法ポリカーボネートより流動挙動の非ニュートン性が大きく、成形流動性に優れており、広範な用途に使用することができる。また、その際には必要に応じ、耐熱安定剤、酸化防止剤、耐候剤、離型剤、滑剤、帯電防止剤、可塑剤、他樹脂やゴム等の重合体、顔料、染料、充填剤、強化剤、難燃剤等を添加して用いても良い。更に、これら添加剤等は、重合終了後のポリカーボネート系樹脂が溶融状態の間に添加してもよいし、ポリカーボネートを一旦ペレタイズした後、添加剤を添加再溶融混練ししてもよい。特にポリカーボネートは熱によって酸化反応を起こし着色してしまうため、酸化防止剤をあらかじめ添加することが特に好ましい。酸化防止剤としてはリン系化合物やフェノール系化合物が挙げられ、リン系化合物としては例えば、トリス（ノニルフェニル）ホスファイト、トリフェニルホスファイト、トリス（エチルフェニル）ホスファイト、トリス（ブチルフェニル）ホスファイト、トリス（ヒドロキシフェニル）ホスファイト、テトラキス（２，４−ジ−ｔ−ブチルフェニル）−４，４’−ビフェニレンジホスファイト、トリス（２，４−ジ−ｔ−ブチルフェニル）ホスファイト等が挙げられ、またフェノール系化合物としては例えば、オクタデシル−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、テトラキスメチレン（３，５−ジ−ｔ−ブチル−４−ヒドロキシヒドロシンナメート）メタン、２，２−チオ［ジエチルビス−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、２，６−ジ−ｔ−ブチル−４−メチルフェノール、２−ｔ−ブチル−６−（３−ｔ−ブチル−２−ヒドロキシ−５−メチルベンジル）−４−メチルフェニルアクリレート、４，４’−ブチリデンビス（３−メチル−６−ｔ−ブチルフェノール）、アルキル化ビスフェノールなどが挙げられる。
【００４４】
本発明で用いる紫外線吸収剤としてはベンゾトリアゾール系化合物、ベンゾフェノン系化合物、ヒドロキシフェニルトリアジン系化合物、サリチル酸フェニルエステル系化合物などからなる紫外線吸収剤が挙げられる。
ベンゾトリアゾール系化合物としては２−（５−メチル−２−ヒドロキシフェニル）−２Ｈ−ベンゾトリアゾール、２−［２−ヒドロキシ−３，５−ビス（α，αジメチルベンジル）フェニル］−２Ｈ−ベンゾトリアゾール、２−（２’−ヒドロキシ−５’−ｔ−オクチルフェニル）ベンゾトリアゾール、２，２−メチレンビス［４−（１，１，３，３−テトラメチレンブチル）−６−（２Ｈ−ベンゾトリアゾール−２−イル）フェノール］、などが挙げられ、ベンゾフェノン系化合物としては２−ヒドロキシ−４−オクトキシベンゾフェノン、２，４−ジヒドロキシベンゾフェノン、２−ヒドロキシ−４−メトキシ−４’−クロルベンゾフェノン、２，２−ジヒドロキシ−４−メトキシベンゾフェノン、２，２−ジヒドロキシ−４，４’−ジメトキシベンゾフェノン等が挙げられる。
【００４５】
またヒドロキシフェニルトリアジン系化合物からなる紫外線吸収剤としては、例えば２，４−ジフェニル−６−（２−ヒドロキシ−４−メトキシフェニル）−１，３，５−トリアジン、２，４−ジフェニル−６−（２−ヒドロキシ−４−エトキシフェニル）−１，３，５−トリアジン、２，４−ジフェニル−６−（２−ヒドロキシ−４−プロポキシフェニル）−１，３，５−トリアジン、２，４−ジフェニル−６−（２−ヒドロキシ−４−ブトキシフェニル）−１，３，５−トリアジン、２，４−ジフェニル−６−（２−ヒドロキシ−４−ヘキシルオキシフェニル）−１，３，５−トリアジン、２，４−ジフェニル−６−（２−ヒドロキシ−４−オクチルオキシフェニル）−１，３，５−トリアジン、２，４−ジフェニル−６−（２−ヒドロキシ−４−ドデシルオキシフェニル）−１，３，５−トリアジン、２，４−ジフェニル−６−（２−ヒドロキシ−４−ベンジルオキシフェニル）−１，３，５−トリアジン、２，４−ジフェニル−６−（２−ヒドロキシ−４−（２−ブトキシエトキシ）フェニル）−１，３，５−トリアジン、２，４−ジ−ｐ−トルイル−６−（２−ヒドロキシ−４−メトキシフェニル）−１，３，５−トリアジン、２，４−ジ−ｐ−トルイル−６−（２−ヒドロキシ−４−エトキシフェニル）−１，３，５−トリアジン、２，４−ジ−ｐ−トルイル−６−（２−ヒドロキシ−４−プロポキシフェニル）−１，３，５−トリアジン、２，４−ジ−ｐ−トルイル−６−（２−ヒドロキシ−４−ブトキシフェニル）−１，３，５−トリアジン、２，４−ジ−ｐ−トルイル−６−（２−ヒドロキシ−４−ヘキシルオキシフェニル）−１，３，５−トリアジン、２，４−ジ−ｐ−トルイル−６−（２−ヒドロキシ−４−オクチルオキシフェニル）−１，３，５−トリアジン、２，４−ジ−ｐ−トルイル−６−（２−ヒドロキシ−４−ドデシルオキシフェニル）−１，３，５−トリアジン、２，４−ジ−ｐ−トルイル−６−（２−ヒドロキシ−４−ベンジルオキシフェニル）−１，３，５−トリアジン、２，４−ジ−ｐ−トルイル−６−（２−ヒドロキシ−４−（２−ヘキシルオキシエトキシ）フェニル）−１，３，５−トリアジン等が挙げられ、またサリチル酸フェニルエステル系紫外線吸収剤としてはパラ−ｔ−ブチルフェニルサリチル酸エステル、パラ−オクチルフェニルサリチル酸エステル等が挙げられる。
【００４６】
このうちより揮発しにくいベンゾトリアゾール系化合物、ヒドロキシフェニルトリアジン系化合物からなる紫外線吸収剤がより好ましい。
ポリカーボネートシート中における該紫外線吸収剤の配合量は０．０１〜２０重量％が好ましく、より好ましくは０．０２〜１５重量％である。０．０１重量％未満の場合、耐候性効果が小さく、逆に２０重量％を越えるとポリカーボネートシートそのものが着色されてしまい透明性が特徴であるポリカーボネートシートにおいて問題である。
【００４７】
該紫外線吸収剤をポリカーボネートに配合する方法について制限はなく。例えばポリカーボネートの重合過程において紫外線吸収剤を添加し配合させる方法や、ポリカーボネートと紫外線吸収剤をドライブレンドしたあと押出機を通し、加熱溶融下で混練する方法、ポリカーボネートシートの成形中に紫外線吸収剤をサイドフィードする方法等を挙げることができる。
【００４８】
またポリカーボネートシートの成形法についても制限はなく、押出成形法、プレス成形法、射出成形法等によって成形できるが、連続的に均一な品質のシートを成形できる押出成形法が好ましい。。
押出成形法は、粉末状またはペレット状のポリカーボネート原料を押出成形法により成形機内で加熱、溶融、混練し、Ｔダイ等を通してシート状に押し出し、次いで２〜４本のポリッシングロールを用いて冷却固化してシートとする方法である。この時、成形機から吐き出されるポリカーボネートの樹脂温は２４０〜２９０℃に調整することが好ましく、更に好ましくは２６０〜２８０℃である。２４０℃未満の樹脂温では成形機の負荷が著しく増大し成形できず、逆に２９０℃を越える樹脂温で成形すると、紫外線吸収剤が成形中揮発してしまい、かつ熱による着色や加水分解等の問題が発生する。成形機から吐き出される樹脂温は成形機加熱シリンダー温度やスクリュー回転速度によって成形中に調整でき、また必要に応じてＬ／Ｄや圧縮率、混練ゾーン等スクリュー形状の変更によっても調整ができる。
【００４９】
透明なシートを成形するためには、成形機のシリンダー及びスクリュー、ポリッシングロール、ガイドロール等ポリカーボネートと直接接触する部分にはハードクロムメッキ等が施されていることが好ましい。
本発明でいうポリカーボネートシートは、前述のポリカーボネートを単独でシート化した単層シートでも、前述のポリカーボネートを含む複数の樹脂を積み重ねた積層シートであってもよい。積層シートのとしては、例えば本発明の耐候性ポリカーボネートシートの表面にアクリル系樹脂や別のポリカーボネート系樹脂、シリコーン系樹脂、フッ素系樹脂などをコーティング法やフイルムラミネート法、共押出法などの方法で積み重ねた積層シートや、逆にアクリル系樹脂や別のポリカーボネート系樹脂に本発明の耐候性ポリカーボネートシートを積層させたものなどを挙げることができる。
【００５０】
本発明の耐候性ポリカーボネートシートは、市販の耐候性ポリカーボネートシート同様に、熱成形、切削、接着、冷間曲げ、印刷等の二次加工を施すことができる。特に熱成形において、本発明の耐候性ポリカーボネートシートは市販のシートと比べて低温で成形できるためシート中に配合された紫外線吸収剤の損失がほとんどなく、熱成形後も優れた耐候性を有する。ここでいう熱成形とは、ポリカーボネートシートを加熱軟化させ、特定の形状に成形加工することをいい、例えば加熱折り曲げ加工、加熱曲面成形加工、フリーブロー成形、圧空成形、真空成形、フリープレス成形、プラグアシスト真空成形、ドレープ成形、真空スナップバック成形、リバースドロー成形などが挙げられる。
【００５１】
また、本発明における耐候性ポリカーボネートシートの厚みは１〜２０ｍｍの範囲で自由に設計できる。
【００５２】
【発明の実施の形態】
以下に実施例、比較例を用いて本発明の効果をさらに具体的に説明する。
なお各項目の評価は以下の方法で測定した。また、ポリカーボネートの完全加水分解と液体クロマトグラフィーの測定法は明細書に記載した方法で行った。
（１）重量平均分子量の測定。
【００５３】
ゲルパーミエーションクロマトグラフィー（ＧＰＣ）で測定した。（２）ポリカーボネートシート中の紫外線吸収剤濃度の測定。
試験片をクロロホルムに溶解し、高速液体クロマトグラフィー（島津製作所（株）製 型式ＬＣ−６Ａ）によって構造分析を行い、紫外線吸収剤構造部分のスペクトルピーク面積を求め、あらかじめ求めておいた標準サンプルの検量線から、ポリカーボネートシート中に含まれる紫外線吸収剤の残存濃度を求めた。
【００５４】
（３）耐候性
スガ試験機製のサンシャインウエザーメーターでサンシャインスーパーロングライフカーボンを使用し、温度６３℃一定下、降雨無し２時間と降雨１８分のサイクルを繰り返す条件で試験片を１０００時間暴露した。
【００５５】
評価としては暴露前後の黄色度の変化をＪＩＳ Ｋ ７１０３に準拠して測定した。
黄変度（ΔＹＩ）＝（暴露前の黄色度）−（暴露前の黄色度）
黄変度（ΔＹＩ）の値が大きいと初期値に比べて耐候性試験の結果黄色味が濃くなった（着色した）ことを意味し、この黄変度が４を超えると着色したことが目視で明らかにわかる。
【００５６】
【実施例１】
攪拌槽型第１（Ａ）（Ｂ）重合器、攪拌槽型第２重合器、攪拌槽型第３重合器、多孔板型第１重合器及び多孔板型第２重合器を連結した連続プロセスで、芳香族ポリカーボネートを製造した。但し、撹拌槽第１重合器は（Ａ）と（Ｂ）を切り替えながらバッチ的に運転し、その他の重合器は連続的に運転した。撹拌槽第１重合器（Ａ）、（Ｂ）の内容積は１００リットル、撹拌槽第２重合器及び撹拌槽第３重合器の内容積は５０リットルであり、撹拌翼はいずれもアンカー型である。多孔板型第１重合器、及び多孔板型第２重合器は、孔径７．５ｍｍの孔を５０個有する多孔板を備えており、各孔には１ｍｍ径のＳＵＳ３１６Ｌ製ワイヤ状ガイドが貫通して設置されている。ガイドに沿わせ落下させる高さは８ｍである。また、各反応器は、各反応器を連結する配管の長さと太さが最小になるように配置した。
【００５７】
撹拌槽第１重合器は（Ａ）、（Ｂ）ともに、温度１８０℃、圧力常圧、シール窒素ガス流量１リットル／ｈｒの条件である。撹拌槽第１重合器（Ａ）に、芳香族ジヒドロキシ化合物としてのビスフェノールＡ及び炭酸ジエステルとしてのジフェニルカーボネート（対ビスフェノールＡモル比１．０４）を８０Ｋｇ仕込み、更にビスフェノールＡジナトリウム塩をナトリウム原子として仕込みビスフェノールＡに対して２０ｐｐｂになるように添加し、４時間溶融混合した後、５Ｋｇ／ｈｒで連続に撹拌槽第２重合器に供給した。撹拌槽第１重合器（Ａ）から撹拌槽第２重合器に供給している間に、撹拌槽第１重合器（Ｂ）に、撹拌槽第１重合器（Ａ）と同様にビスフェノールＡとジフェニルカーボネート及びビスフェノールＡジナトリウム塩を溶融混合し、撹拌槽第１重合器（Ａ）が空になった時点で撹拌槽第１重合器（Ｂ）に切り替えた。この後、同様にして撹拌槽第１重合器（Ａ）、（Ｂ）はバッチ的に切り替えながら撹拌槽第２重合器に重合中間体を連続に５Ｋｇ／ｈｒで供給し続けた。
【００５８】
撹拌槽第２重合器は内容量が２０リットルに達したら、内容量２０リットルを一定に保つように撹拌槽第３重合器に重合中間体を連続に供給した。撹拌槽第２重合器は、反応温度２３０℃、反応圧力１００ｍｍＨｇ、窒素ガス流量２リットル／ｈｒの条件であった。撹拌槽第３重合器は内容量が２０リットルに達したら、内容量２０リットルを一定に保つように多孔板型第１重合器に重合中間体を連続に供給した。撹拌槽第３重合器は、反応温度２４０℃、反応圧力１０ｍｍＨｇ、窒素ガス流量２リットル／ｈｒの条件であった。
【００５９】
多孔板型第１重合器は内容量が１０リットルに達したら、内容量１０リットルを一定に保つように多孔板型第２重合器に重合中間体を連続に供給した。多孔板型第１重合器は、反応温度２４５℃、反応圧力１．５ｍｍＨｇ、窒素ガス流量４リットル／ｈｒの条件であった。多孔板型第２重合器は内容量が１０リットルに達したら、内容量１０リットル一定に保つように溶融重合体を連続にノズルより抜き出し、ストランドカットによりペレット化した。多孔板型第２重合器は、反応温度２４５℃、反応圧力０．３ｍｍＨｇ、窒素ガス流量２リットル／ｈｒの条件であった。このときのΣ（Ｋｉ×Ｔｉ×Ｈｉ）は０．８３であった。
【００６０】
このようにして得られたポリカーボネートは、のリテンションタイムがビスフェノールＡより長い化合物の総量が０．０５重量％であり、またリテンションタイムがビスフェノールＡとジフェニルカーボネートの間にある化合物の総量Ａ（但し、用いた他の芳香族ジヒドロキシ化合物と炭酸ジフェニルは除く）とジフェニルカーボネートより後にある化合物の総量Ｂ（但し、用いた他の芳香族ジヒドロキシ化合物と炭酸ジフェニルは除く）との比Ｂ／Ａは０．２であった。また、該ポリカーボネートの重量平均分子量は２６，８００であった。
【００６１】
該ポリカーボネート９９．９重量％と２−（４，６−ジフェニル−１，３，５−トリアジン−２−イル）−５−（ヘキシル）オキシ−フェノールからなるヒドロキシフェニルトリアジン系化合物製紫外線吸収剤０．１重量％をドライブレンドしたものを、スクリュー径５０ｍｍの押出機を通して加熱溶融混練し、幅３００ｍｍのシート用ダイを用いてシート状に押し出した。次いでシート状の溶融ポリカーボネートを直径２００ｍｍのポリッシングロールに導き冷却固化させてポリカーボネートシートを得た。
【００６２】
このとき押出機から吐き出される樹脂温度を約２６０℃、ダイ温度は２５０℃、ポリッシングロールの表面温度は１３０℃に調整した。また、シートの厚みはポリッシングロールの間隙を制御することによって３ｍｍになるよう調整した。このようにして得られたポリカーボネートシート中に残存する紫外線吸収剤の濃度を測定したところ０．０９重量％あり、シート押出成形中ほとんど紫外線吸収剤の損失がないことがわかる。
【００６３】
このポリカーボネートシートについて耐候性試験を行った結果、黄変度（ΔＹＩ）が１であり、耐候性も良好であることがわかった。
また得られたポリカーボネートシートを用い真空プレス成形を行った結果、熱成形による紫外線吸収剤の損失はほとんどなく、熱成形後も耐候性は良好で加熱成形前と同性能であった。
【００６４】
【実施例２】
ポリカーボネートに配合する紫外線吸収剤を２，２−メチレンビス［４−（１，１，３，３−テトラメチレンブチル）−６−（２Ｈ−ベンゾトリアゾール−２−イル）フェノール］からなるベンゾトリアゾール系化合物製に変更した以外は実施例１と同様に行った。
【００６５】
このようにして得られたポリカーボネートシート中に残存する紫外線吸収剤の濃度を測定したところ０．０９重量％あり、シート押出成形中ほとんど紫外線吸収剤の損失がないことがわかる。
このポリカーボネートシートの耐候性試験を行った結果、黄変度（ΔＹＩ）が１であり、耐候性も実施例１同様に良好であることがわかった。
【００６６】
また得られたポリカーボネートシートを用い真空プレス成形を行った結果、実施例１と同様に熱成形による紫外線吸収剤の損失はほとんどなく、熱成形後も耐候性は良好で加熱成形前と同性能であった。
【００６７】
【実施例３】
押出機から吐き出される樹脂温度が２５０℃になるように成形条件を調整した以外は実施例１と同様に行った。
押出成形状況としては、押出機の負荷が上がり気味であったがシート成形自体は問題なく行えた。また、このようにして得られたポリカーボネートシート中に残存する紫外線吸収剤の濃度を測定したところ０．０９量％あり、実施例１同様シート押出成形中ほとんど紫外線吸収剤の損失がないことがわかる。
【００６８】
このポリカーボネートシートの耐候性試験を行った結果、黄変度（ΔＹＩ）が１であり、耐候性も良好であることがわかった。
また得られたポリカーボネートシートを用い真空プレス成形を行った結果、実施例１と同様に熱成形による紫外線吸収剤の損失はほとんどなく、熱成形後も耐候性は良好で加熱成形前と同性能であった。
【００６９】
【比較例１】
各反応器の温度を変更し、リテンションタイムがビスフェノールＡより長い化合物の総量が０．１５重量％、またリテンションタイムがビスフェノールＡとジフェニルカーボネートの間にある化合物の総量Ａ（但し、用いた他の芳香族ジヒドロキシ化合物と炭酸ジフェニルは除く）とジフェニルカーボネートより後にある化合物の総量Ｂ（但し、用いた他の芳香族ジヒドロキシ化合物と炭酸ジフェニルは除く）との比Ｂ／Ａが０．９５になるように調整したポリカーボネートを使用した以外は実施例１と同様に評価した。このときのポリカーボネートの重量平均分子量は２６，９００であった。
【００７０】
しかし実施例１と同じ成形条件で成形すると、押出機の負荷が上がり過負荷停止を繰り返し、安定に成形できない。押出機負荷が実施例１と同程度になるように成形条件を調整したところ、押出機から吐き出される樹脂温度が２９５℃になった。
押出機負荷を実施例１と同程度になるような条件でシート成形し得られたポリカーボネートシート中に残存する紫外線吸収剤の濃度を測定したところ０．０６量％あり、シート押出成形中に紫外線吸収剤が減少していることがわかる。
【００７１】
このポリカーボネートシートについて耐候性試験を行ったところ、黄変度（ΔＹＩ）が４であり、紫外線吸収剤を配合した効果が小さくなることがわかった。また得られたポリカーボネートシートを用い実施例１同様に真空プレス成形を行った結果、加熱軟化時に紫外線吸収剤の揮発・損失が発生し、揮発した紫外線吸収剤がプレス金型に付着したため、成形体の表面が粗れ、かつ熱成形前と比べても耐候性が更に悪化した。
【００７２】
【比較例２】
重量平均分子量が２６，８００のホスゲン法で製造された市販ポリカーボネートを実施例１と同様に評価した。
この時も実施例１と成形条件で成形すると、押出機の負荷が上がり過負荷停止状態となり、安定に成形できない。押出機負荷が実施例１と同程度になるように成形条件を調整したところ、押出機から吐き出される樹脂温度が３００℃になった。
【００７３】
押出機負荷を実施例１と同程度になるような条件でシート成形し得られたポリカーボネートシート中に残存する紫外線吸収剤の濃度を測定したところ０．０３重量％あり、シート押出成形中に紫外線吸収剤が減少していることがわかる。このポリカーボネートシートについても耐候性試験を行ったところ、黄変度（ΔＹＩ）は６もあり、紫外線吸収剤を配合した効果がほとんどないことがわかった。
【００７４】
また得られたポリカーボネートシートを用い実施例１同様に真空プレス成形を行った結果、比較例１と同様に加熱軟化時に紫外線吸収剤の揮発・損失が発生し、揮発した紫外線吸収剤がプレス金型に付着したため、成形体の表面が粗れ、かつ熱成形前と比べても耐候性が更に悪化した。
【００７５】
【表１】

【００７６】
【発明の効果】
本発明によって熱成形等の二次加工後も耐候性を維持したポリカーボネートシートと、成形中に発生する紫外線吸収剤の損失を防止した該耐候性ポリカーボネートシートの製法を提供することができ、更に広範囲な用途に使用することができるようになった。
【００７７】
【図の説明】
【００７８】
【図１】明細書記載の方法で測定した標準化合物混合物の液体クロマトグラフィーチャート。
【００７９】
【図２】明細書記載の方法で測定したポリカーボネートを完全加水分解したものの液体クロマトグラフィーチャート。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a weather-resistant polycarbonate sheet and a method for producing the same.
[0002]
[Prior art]
Polycarbonate sheet is excellent in impact resistance, transparency, flame resistance, etc. and various materials such as building materials represented by window materials, carport roofing materials, veranda waist plates, road materials such as transparent soundproof plates, railway vehicle materials, etc. It is used in the field and its use is expected to expand in the future.
[0003]
However, the polycarbonate sheet has the disadvantage of poor weather resistance, especially when used in places exposed to ultraviolet rays, such as outdoors, resulting in a decrease in optical performance such as yellowing and loss of transparency, mechanical strength such as a decrease in tensile strength and a decrease in impact resistance. The deterioration of properties occurred and was a problem.
A commonly used measure for improving the weather resistance of a polycarbonate sheet is to incorporate an ultraviolet absorber. In particular, a number of methods for coating a polycarbonate sheet surface with a polycarbonate thin film containing a large amount of an ultraviolet absorber on the surface of the polycarbonate sheet have been proposed in recent years. For example, Japanese Patent Publication No. 3-54626, Japanese Patent Publication No. 6-41162, and Japanese Patent Laid-Open No. And the like.
[0004]
Now, when the polycarbonate is formed into a sheet, the powdery or pellet-like polycarbonate raw material is heated, melted and kneaded in the molding machine by an extrusion molding method, and extruded into a sheet through a T-die or the like. A method of cooling and solidifying a sheet using a polishing roll (glazing roll) is often used.
Polycarbonate has a problem that it is colored when molded at high temperatures. However, with the current polycarbonate sheet molding technology, if the molding temperature is lowered, the load on the molding machine increases and stable production cannot be achieved. Molded with. In addition, in order to lower the molding temperature, studies have been made to reduce the molecular weight of polycarbonate to make it easier to flow. However, resin dripping occurs between the T die and the polishing roll, making it impossible to mold. It is difficult and how to mold at a low molding temperature, that is, a resin temperature close to about 240 ° C., which is the melting point of polycarbonate, is a problem in the polycarbonate molding technology.
[0005]
At present, if a polycarbonate compounded with an ultraviolet absorber is molded into a sheet under this high molding temperature, the compounded ultraviolet absorber volatilizes during molding, and the initial amount of the ultraviolet absorber in the sheet product is As a result, the effect of improving the weather resistance is not as much as expected, which is a problem. In addition, the volatilized UV absorber adheres to the surface of the T-die or polishing roll, and the surface of the sheet product is soiled. It has occurred.
[0006]
If the amount of the UV absorber is increased in anticipation of volatile matter, the surface of the T-die and polishing roll will frequently become dirty, making it difficult to obtain a sheet with good appearance, and if the molding temperature is lowered, the load on the molding machine will be reduced. As a result, there is no good molding method so far.
In addition, the polycarbonate sheet is generally used after being formed into a predetermined shape by secondary processing such as thermoforming, and even if a sheet with an increased amount of ultraviolet absorber is anticipated as described above, a volatile component can be obtained. In such thermoforming, the loss of the UV absorber occurs again, so that the weather resistance cannot be maintained as a molded product of the sheet, and improvement has been demanded.
[0007]
For this reason, researches on UV absorbers that are less likely to volatilize are being actively conducted, and UV absorbers that have low weight loss even at high temperatures have been proposed. For example, JP-A-62-146952 and JP-A-5-93089 can be mentioned. Certainly, these ultraviolet absorbers have reduced weight loss at high temperatures, but improvement of the ultraviolet absorber alone is still insufficient, and there is a need for a polycarbonate that can be molded at a low molding temperature.
[0008]
[Problems to be solved by the invention]
An object of the present invention is to provide a polycarbonate sheet that maintains weather resistance even after secondary processing such as thermoforming, and also provides a method for producing the weather-resistant polycarbonate sheet that prevents loss of ultraviolet absorbers that occur during sheet molding It is to be.
[0009]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present inventors diligently studied a polycarbonate resin, and as a result, found that several types of heterogeneous bonds exist in the polycarbonate obtained by the transesterification method, and the amount of the heterogeneous bonds. It was found that the non-Newtonian property of the flow behavior can be maintained by setting the to a specific range. When a raw material composition in which an ultraviolet absorber is blended with this polycarbonate is formed into a sheet, surprisingly, this polycarbonate sheet raw material composition can be formed into a sheet at a lower temperature than a composition using a conventional polycarbonate having the same molecular weight. And, the obtained polycarbonate sheet was able to be thermoformed at a low temperature, and there was almost no loss of the UV absorber during thermoforming, and it was found that the weather resistance could be maintained even after thermoforming of the sheet, and reached the present invention. Is.
[0010]
That is, the present invention
(1) Polycarbonate having a small amount of different bondsIs a polycarbonate produced by transesterification from an aromatic dihydroxy compound and a carbonic acid diester, and the polycarbonate is completely hydrolyzed and then reverse phase liquid chromatography is used to prepare methanol and a 0.1% aqueous phosphoric acid solution. Of a compound having a longer retention time than the aromatic dihydroxy compound when measured under conditions where the methanol / 0.1% phosphoric acid aqueous solution ratio starts from 20/80 and is gradient to 100/0. The total amount (detected with a UV detector with a wavelength of 300 nm and calculated from the peak area using the extinction coefficient of salicylic acid, excluding the carbonic acid diester) is 0.015 to 0.09% by weight based on the polycarbonate Polycarbonate in the rangeA weather-resistant polycarbonate sheet comprising 0.01 to 20% by weight of an ultraviolet absorber,
(2The above (characterized in that 85 mol% or more of the aromatic dihydroxy compound is bisphenol A)1) Weatherproof polycarbonate sheet as described,
(3) Total amount A of compounds with retention time between bisphenol A and diphenyl carbonate (excluding other aromatic dihydroxy compounds and diphenyl carbonate used) and total amount B of compounds after diphenyl carbonate (however, other used) (1), wherein the ratio B / A between the aromatic dihydroxy compound and diphenyl carbonate is 0.8 or less.Or(2)InProviding the weather-resistant polycarbonate sheet described above, and
(4) The above (1) to (1), wherein the ultraviolet absorber comprises a benzotriazole compound.3)In any one ofWeatherproof polycarbonate sheet as described,
(5(1) to (1) above, wherein the ultraviolet absorber comprises a hydroxyphenyltriazine compound.3)In any one ofThe weather-resistant polycarbonate sheet described is provided. Also,
(6)Above (1) to (5)In any one ofIn molding the weather-resistant polycarbonate sheet described,Made of polycarbonate with a small amount of heterogeneous bondsAdjust the resin temperature of the polycarbonate sheet raw material composition to 240-290 ° CAnd extrude from the sheet forming machineThe present invention relates to a process for producing a weather-resistant polycarbonate sheet.
[0011]
Hereinafter, the present invention will be described in detail.
The weather-resistant polycarbonate sheet of the present invention is a sheet made of a composition in which a UV absorber is blended with a small amount of polycarbonate having different types of bonds, and is thermoformed at a lower temperature than a commercially available sheet during secondary processing such as thermoforming. It is a sheet that has no loss of UV absorber even after thermoforming and maintains weather resistance after thermoforming.
[0012]
A polycarbonate having a small amount of heterogeneous bonds, which is a raw material for the polycarbonate sheet of the present invention, is produced by a transesterification method, and the polycarbonate is completely hydrolyzed and subjected to methanol using reverse phase liquid chromatography. And a 0.1% phosphoric acid aqueous solution mixed eluent, the retention time was measured when the methanol / 0.1% phosphoric acid aqueous solution ratio was measured from 20/80 to a gradient of 100/0. The total amount of compounds longer than the aromatic dihydroxy compound (detected with a UV detector with a wavelength of 300 nm and calculated from the peak area using the extinction coefficient of salicylic acid, excluding the carbonic acid diester) was 0 for the polycarbonate. It is necessary to be in the range of 0.01 to 0.10% by weight. The compound is presumed to be due to heterogeneous bonds by-produced in the process of producing the polycarbonate by the transesterification method, and if the total amount of the compound is less than the above range, the non-Newtonian nature of the flow behavior is decreased. The fluidity under shear, that is, the molding fluidity is undesirably lowered, and if it exceeds the above range, the mechanical properties such as tensile elongation and IZOD impact strength are undesirably lowered. Preferably, it exists in the range of 0.015-0.09 weight%, More preferably, it exists in the range of 0.02-0.08 weight%.
[0013]
Polycarbonate can be easily hydrolyzed, and the method of complete hydrolysis is not particularly limited. However, a hydrolysis method at room temperature as described in Polymer Degradation and Stability 45 (1994), 127 to 137 is used in the decomposition process. This is preferable because the polycarbonate can be completely hydrolyzed without any side reaction. In the present invention, 55 mg of polycarbonate was dissolved in 2 ml of tetrahydrofuran, 0.5 ml of 5N potassium hydroxide methanol solution was added, and the mixture was stirred at room temperature for 2 hours for complete hydrolysis. Thereafter, 0.3 ml of concentrated hydrochloric acid was added, and the measurement was performed by reverse phase liquid chromatography.
[0014]
Reversed-phase liquid chromatography uses a mixed eluent consisting of methanol and 0.1% aqueous phosphoric acid as the eluent, and starts with a methanol / 0.1% aqueous phosphoric acid ratio from 20/80 and gradients to 100/0. Measurement was performed under the conditions, and detection was calculated from the peak area using a UV detector having a wavelength of 300 nm, and quantification was performed using the absorption coefficient of salicylic acid. In this invention, although other conditions are not specifically limited, It analyzed on the following conditions.
[0015]
Column: GL Sciences Inertsil ODS-3 (registered trademark)
Flow rate: 1 ml / min
Injection volume: 20 μl
An example of an analysis chart analyzed by the method is shown in FIGS. FIG. 1 is a liquid chromatography chart of a pure compound. Peak 3 is bisphenol A, which is a typical aromatic dihydroxy compound, and peak 4 is diphenyl carbonate, which is a typical carbonic acid diester. FIG. 2 is a reverse phase liquid chromatography chart of a completely hydrolyzed polycarbonate polymerized by transesterification using bisphenol A as an aromatic dihydroxy compound and diphenyl carbonate as a carbonic acid diester. In FIG. 2, peak number 8 is bisphenol A, and the subsequent peaks 9 to 17 are compounds that are considered to be based on heterogeneous bonds.
[0016]
Further, in the present invention, in a polycarbonate using bisphenol A as an aromatic dihydroxy compound in an amount of 85 mol% or more, the retention time is bisphenol when the polycarbonate is completely hydrolyzed and measured by reverse phase liquid chromatography. The total amount of compounds A between A and diphenyl carbonate (excluding other aromatic dihydroxy compounds and diphenyl carbonate used) and the total amount B of compounds after diphenyl carbonate (however, other aromatic dihydroxy compounds used and The ratio (B / A) to (excluding diphenyl carbonate) is preferably 0.8 or less. If B / A exceeds 0.8, the mechanical properties tend to decrease, such being undesirable.
[0017]
The polycarbonate used in the present invention is produced by an ester exchange method from an aromatic dihydroxy compound and a carbonic acid diester.
In the present invention, the aromatic dihydroxy compound is a compound represented by HO—Ar—OH (wherein Ar is a divalent aromatic residue, such as phenylene, naphthylene, biphenylene, pyridylene, − Ar₁-Y-Ar₂A divalent aromatic group represented by-. Ar₁And Ar₂Each independently represents a divalent carbocyclic or heterocyclic aromatic group having 5 to 70 carbon atoms, and Y represents a divalent alkane group having 1 to 30 carbon atoms. ).
[0018]
Divalent aromatic group Ar₁, Ar₂In which one or more hydrogen atoms do not adversely influence the reaction, for example, a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a phenyl group, a phenoxy group, It may be substituted with a vinyl group, a cyano group, an ester group, an amide group, a nitro group, or the like.
[0019]
Preferable specific examples of the heterocyclic aromatic group include aromatic groups having one or more ring-forming nitrogen atoms, oxygen atoms or sulfur atoms.
Divalent aromatic group Ar₁, Ar₂Represents, for example, a group such as substituted or unsubstituted phenylene, substituted or unsubstituted biphenylene, substituted or unsubstituted pyridylene. The substituents here are as described above.
[0020]
The divalent alkane group Y is, for example, an organic group represented by the following chemical formula 1.
[0021]
[Chemical 1]

[0022]
(Wherein R₁, R₂, R₃, R₄Are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 ring carbon atoms, and a carbocyclic aromatic having 5 to 10 ring carbon atoms. Group, a C6-C10 carbocyclic aralkyl group. k represents an integer of 3 to 11, and R₅And R₆Are individually selected for each X and, independently of one another, represent hydrogen or an alkyl group having 1 to 6 carbon atoms, where X represents carbon. R₁, R₂, R₃, R₄, R₅, R₆In the above, in the range where one or more hydrogen atoms do not adversely affect the reaction, for example, a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a phenyl group, a phenoxy group, It may be substituted with a vinyl group, a cyano group, an ester group, an amide group, a nitro group, or the like. )
Examples of such a divalent aromatic group Ar include those represented by the following chemical formula 2.
[0023]
[Chemical 2]

[0024]
(Wherein R₇, R₈Are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 ring carbon atoms, or a phenyl group, and m and n Is an integer from 1 to 4, and when m is 2 to 4, each R₇May be the same or different, and when n is 2 to 4, each R₈May be the same or different. )
Further, the divalent aromatic group Ar is -Ar₁-Z-Ar₂It may be indicated by −.
[0025]
(Wherein Ar₁, Ar₂Is as defined above, Z is a single bond or —O—, —CO—, —S—, —SO 2 —, —SO—, —COO—, —CON (R₁Represents a divalent group such as-. However, R₁Is as described above. )
Examples of such divalent aromatic group Ar include those represented by the following chemical formula 3.
[0026]
[Chemical 3]

[0027]
(Wherein R₇, R₈, M and n are as described above. )
The aromatic dihydroxy compound used in the present invention may be used alone or in combination of two or more. A typical example of the aromatic dihydroxy compound is bisphenol A, and bisphenol A is preferably used in an amount of 85% or more. Further, these aromatic dihydroxy compounds preferably have a low content of chlorine atoms and alkali or alkaline earth metal, and are preferably not substantially contained if possible.
[0028]
The carbonic acid diester used in the present invention is represented by the following chemical formula 4.
[0029]
[Formula 4]

[0030]
(Wherein Ar₃, Ar₄Each represents a monovalent aromatic group. )
Ar₃And Ar₄Represents a monovalent carbocyclic or heterocyclic aromatic group, this Ar₃, Ar₄In which one or more hydrogen atoms do not adversely influence the reaction, for example, a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a phenyl group, a phenoxy group, It may be substituted with a vinyl group, a cyano group, an ester group, an amide group, a nitro group, or the like. Ar₃, Ar₄May be the same or different.
[0031]
Monovalent aromatic group Ar₃And Ar₄As typical examples of these, there can be mentioned a phenyl group, a naphthyl group, a biphenyl group, and a pyridyl group. These may be substituted with one or more substituents as described above.
Preferred Ar₃And Ar₄As, for example, the following chemical formula 5 and the like can be mentioned.
[0032]
[Chemical formula 5]

[0033]
Typical examples of the carbonic acid diester include substituted or unsubstituted diphenyl carbonates represented by the following chemical formula (6).
[0034]
[Chemical 6]

[0035]
(Wherein R₉And R₁₀Each independently represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 ring carbon atoms, or a phenyl group, and p and q are 1 When p is an integer of 5 or more and p is 2 or more, each R9 may be different, and when q is 2 or more, each R10 may be different. )
Among these diphenyl carbonates, preferred are symmetric diaryl carbonates such as unsubstituted diphenyl carbonate, lower alkyl-substituted diphenyl carbonates such as ditolyl carbonate and di-t-butylphenyl carbonate, and particularly diaryls having the simplest structure. Diphenyl carbonate which is a carbonate is preferred.
[0036]
These carbonic acid diesters may be used alone or in combination of two or more. In addition, these diaryl carbonates preferably have a low content of chlorine atoms and alkali or alkaline earth metal, and are preferably not substantially contained if possible.
The use ratio (charge ratio) of the aromatic dihydroxy compound and the carbonic acid diester varies depending on the type of the aromatic dihydroxy compound and diaryl carbonate used, the polymerization temperature and other polymerization conditions, and the molecular weight and terminal ratio of the polycarbonate to be obtained. There is no particular limitation. The diaryl carbonate is used in an amount of usually 0.9 to 2.5 mol, preferably 0.95 to 2.0 mol, more preferably 0.98 to 1.5 mol, relative to 1 mol of the aromatic dihydroxy compound. The The ratio of hydroxy terminal to non-hydroxy terminal is controlled in the range of 0/100 to 100/0.
[0037]
In the present invention, an aromatic polyvalent hydroxy compound for introducing a branched structure may be used in a small amount within a range that does not impair the object of the present invention, or an aromatic monovalent compound for terminal conversion or molecular weight adjustment. A hydroxy compound may be used in combination.
In the present invention, the transesterification method refers to a method in which the above compound is polycondensed in a transesterification reaction in a molten state with heating in the presence or absence of a catalyst under reduced pressure or / and under an inert gas flow. The polymerization method and apparatus are not limited. For example, stirring tank type reactor, thin film reactor, centrifugal thin film evaporation reactor, surface renewal type biaxial kneading reactor, biaxial horizontal type stirring reactor, wet wall type reactor, perforated plate type that polymerizes while freely falling Using a reactor, a perforated plate reactor with a wire that is polymerized while dropping along the wire, etc., these can be easily produced singly or in combination. Alternatively, it can also be produced by a solid phase polymerization method in which a transesterification reaction is performed in a molten state to produce a prepolymer, and then the degree of polymerization is increased in a solid phase under reduced pressure or / and an inert gas flow. Moreover, there is no restriction | limiting in particular in the material of these reactors, Usually, it selects from stainless steel, nickel, glass lining, etc.
[0038]
The polycarbonate used by this invention should just be manufactured by the above transesterification methods, and the manufacturing method is not specifically limited. Usually, the reaction temperature for the transesterification for producing the polycarbonate is usually selected in the range of 50 to 350 ° C., preferably 100 to 300 ° C. In general, at temperatures higher than the above range, the resulting polycarbonate tends to be highly colored and inferior in thermal stability. At temperatures below the above range, it is known that the polymerization reaction is slow and impractical. In the present invention, in the transesterification method, it is preferable to produce a polycarbonate by controlling the temperature and residence time of the polycarbonate being produced within a specific range that satisfies the formula (1). If the relationship between the temperature and the residence time is larger than the above range, the mechanical properties such as tensile elongation and IZOD impact strength are undesirably lowered, and if it is smaller than the above range, the molding fluidity is undesirably lowered.
[0039]

Ti: Average temperature of polycarbonate in step i (° C.)
Hi: Average residence time in process i (hr)
ki: Coefficient at the Ti temperature expressed by the equation (2)
ki = 1 / aTi^-B                (2)
However, when Ti <240 ° C
a = 1.60046 × 10⁵
b = 0.472
However, when 240 ℃ ≦ Ti <260 ℃
a = 4 × 10⁴⁹
b = 19.107
However, when 260 ℃ ≦ Ti
a = 1 × 10¹²²
b = 49.082
In the production of polycarbonate by the transesterification method, the temperature, residence time and reaction pressure are generally changed in stages, and the formula (1) shows the sum of k × T × H in each stage. . For example, Σ (ki × Ti ×) when continuous polymerization is performed by connecting a dissolution and mixing tank of an aromatic dihydroxy compound and a carbonic acid diester, a stirring tank reactor, a centrifugal thin film evaporation reactor, and a surface renewal biaxial kneading reactor. Hi) is (k × T × H in the dissolution and mixing tank) + (k × T × H in the pipe from the dissolution and mixing tank to the stirring tank reactor) + (k × T in the stirring tank reactor) × H) + (k × T × H of piping from the stirred tank reactor to the centrifugal thin film evaporation reactor) + (k × T × H in the centrifugal thin film evaporation reactor) + (centrifugal thin film evaporation reaction) K × T × H of piping from the vessel to the surface renewal type biaxial kneading reactor) + (k × T × H in the surface renewal type biaxial kneading reactor) + (extracted from the surface renewal type biaxial kneading reactor) (K × T × H of piping up to the nozzle), and shows the total at all stages including the piping. In this case, i process means each stage and process of each mixing tank, a reactor, and piping which connects it. When there is a heater in the middle of the pipe connecting the reactor and the reactor, the pipe to the reactor and the heater, the heater, and the pipe to the heater and the reactor are i processes, respectively. The average temperature of the polycarbonate means the average value of the temperatures in the i process. If the temperature is clearly divided into several stages, each stage is divided and the average temperature in that stage is determined as each i process. It may be used. The average residence time is calculated by the holding amount of polycarbonate in each i step / the passing amount per hour or the withdrawal amount.
[0040]
The reaction pressure also varies depending on the molecular weight of the polycarbonate during melt polymerization, and in the range of number average molecular weight of 1000 or less, a range of 50 mmHg to normal pressure is generally used, and in the range of number average molecular weight of 1000 to 2000, In the range of 3 mmHg to 80 mmHg and a number average molecular weight of 2000 or more, 10 mmHg or less, particularly 5 mmHg or less is used.
[0041]
The polymerization by the transesterification method can be carried out without adding a catalyst, but is carried out in the presence of a catalyst as necessary in order to increase the polymerization rate. The polymerization catalyst is not particularly limited as long as it is used in this field, but alkali metal and alkaline earth metal hydroxides such as lithium hydroxide, sodium hydroxide, potassium hydroxide, and calcium hydroxide. Alkali metal salts, alkaline earth metal salts, quaternary ammonium salts of hydrides of boron and aluminum such as lithium aluminum hydride, sodium borohydride, tetramethylammonium borohydride; lithium hydride, sodium hydride Alkali metal and alkaline earth metal hydrides such as calcium hydride; Alkali metal and alkaline earth metal alkoxides such as lithium methoxide, sodium ethoxide and calcium methoxide; Lithium phenoxide, sodium phenoxide, magnesium phenoxy Alyloxides of alkali metals and alkaline earth metals such as LiO—Ar—OLi and NaO—Ar—ONa (Ar is an aryl group); alkali metals and alkaline earth metals such as lithium acetate, calcium acetate and sodium benzoate Organic acid salts; zinc compounds such as zinc oxide, zinc acetate, zinc phenoxide; boron oxide, boric acid, sodium borate, trimethyl borate, tributyl borate, triphenyl borate, (R₁R₂R₃R₄) NB (R₁R₂R₃R₄) Or (R₁R₂R₃R₄) PB (R₁R₂R₃R₄Ammonium borates or phosphonium borates (R)₁, R₂, R₃, R₄Is a compound of boron such as silicon oxide, sodium silicate, tetraalkyl silicon, tetraaryl silicon, diphenyl-ethyl-ethoxy silicon; germanium oxide, germanium tetrachloride, Germanium compounds such as germanium ethoxide and germanium phenoxide; tin compounds bonded to alkoxy groups or aryloxy groups such as tin oxide, dialkyltin oxide, dialkyltin carboxylate, tin acetate, ethyltin tributoxide, organotin compounds, etc. Tin compounds; lead compounds such as lead oxide, lead acetate, lead carbonate, basic carbonate, lead and organic lead alkoxides or aryloxides; quaternary ammonium salts, quaternary phosphonium salts, quaternary arsonium salts Oni such as Antimony compounds such as antimony oxide and antimony acetate; manganese compounds such as manganese acetate, manganese carbonate and manganese borate; titanium compounds such as titanium oxide, titanium alkoxide or aryloxide; zirconium acetate; Examples of the catalyst include zirconium oxide, zirconium alkoxide or aryloxide, and zirconium compounds such as zirconium acetylacetone.
[0042]
When using a catalyst, these catalysts may be used alone or in combination of two or more. The amount of these catalysts used is usually 10 with respect to the aromatic dihydroxy compound as a raw material.^-8˜1% by weight, preferably 10^-7-10^-1It is selected in the range of% by weight.
The molecular weight of the polycarbonate used in the present invention is not particularly limited, but generally the weight average molecular weight is usually in the range of 1000 to 300,000, preferably in the range of 5000 to 100,000, and particularly preferably in the range of 12000 to 80000. Also, the terminal structure is not particularly limited.
[0043]
The polycarbonate used in the present invention is presumed to be a compound having a retention time after the aromatic dihydroxy compound used, that is, a small amount of moderate heterogeneous bonds, as determined by reverse phase liquid chromatography after complete hydrolysis. Since it has a bond, it has excellent color tone and mechanical properties, has a greater non-Newtonian fluidity than phosgene polycarbonate, has excellent molding fluidity, and can be used in a wide range of applications. In that case, if necessary, heat stabilizers, antioxidants, weathering agents, release agents, lubricants, antistatic agents, plasticizers, polymers such as other resins and rubbers, pigments, dyes, fillers, You may add and use a reinforcing agent, a flame retardant, etc. Furthermore, these additives and the like may be added while the polycarbonate-based resin after polymerization is in a molten state, or the pellets may be once pelletized and then the additives may be added and remelted and kneaded. In particular, since polycarbonate causes an oxidation reaction by heat and becomes colored, it is particularly preferable to add an antioxidant in advance. Examples of antioxidants include phosphorus compounds and phenolic compounds. Examples of phosphorus compounds include tris (nonylphenyl) phosphite, triphenylphosphite, tris (ethylphenyl) phosphite, tris (butylphenyl) phosphine. Phyto, tris (hydroxyphenyl) phosphite, tetrakis (2,4-di-t-butylphenyl) -4,4′-biphenylene diphosphite, tris (2,4-di-t-butylphenyl) phosphite, etc. Examples of the phenolic compound include octadecyl-3- (3′-5′-di-t-butyl-4-hydroxyphenyl) propionate, tetrakismethylene (3,5-di-t-butyl-4 -Hydroxyhydrocinnamate) methane, 2,2-thio [diethylbis-3 ( , 5-di-tert-butyl-4-hydroxyphenyl) propionate, 2,6-di-tert-butyl-4-methylphenol, 2-tert-butyl-6- (3-tert-butyl-2-hydroxy-) 5-methylbenzyl) -4-methylphenyl acrylate, 4,4′-butylidenebis (3-methyl-6-tert-butylphenol), alkylated bisphenol and the like.
[0044]
Examples of the ultraviolet absorber used in the present invention include ultraviolet absorbers composed of benzotriazole compounds, benzophenone compounds, hydroxyphenyltriazine compounds, salicylic acid phenyl ester compounds, and the like.
Examples of benzotriazole compounds include 2- (5-methyl-2-hydroxyphenyl) -2H-benzotriazole and 2- [2-hydroxy-3,5-bis (α, αdimethylbenzyl) phenyl] -2H-benzotriazole. 2- (2′-hydroxy-5′-t-octylphenyl) benzotriazole, 2,2-methylenebis [4- (1,1,3,3-tetramethylenebutyl) -6- (2H-benzotriazole- 2-yl) phenol], etc., and examples of the benzophenone compounds include 2-hydroxy-4-octoxybenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxy-4′-chlorobenzophenone, 2, 2-dihydroxy-4-methoxybenzophenone, 2,2-dihydroxy-4,4′-di And methoxybenzophenone.
[0045]
Examples of the ultraviolet absorber comprising a hydroxyphenyltriazine compound include 2,4-diphenyl-6- (2-hydroxy-4-methoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6 (2-hydroxy-4-ethoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-propoxyphenyl) -1,3,5-triazine, 2,4- Diphenyl-6- (2-hydroxy-4-butoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-hexyloxyphenyl) -1,3,5-triazine 2,4-diphenyl-6- (2-hydroxy-4-octyloxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydro Ci-4-dodecyloxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-benzyloxyphenyl) -1,3,5-triazine, 2,4-diphenyl -6- (2-hydroxy-4- (2-butoxyethoxy) phenyl) -1,3,5-triazine, 2,4-di-p-toluyl-6- (2-hydroxy-4-methoxyphenyl)- 1,3,5-triazine, 2,4-di-p-toluyl-6- (2-hydroxy-4-ethoxyphenyl) -1,3,5-triazine, 2,4-di-p-toluyl-6 -(2-hydroxy-4-propoxyphenyl) -1,3,5-triazine, 2,4-di-p-toluyl-6- (2-hydroxy-4-butoxyphenyl) -1,3,5-triazine 2,4-di-p-to Yl-6- (2-hydroxy-4-hexyloxyphenyl) -1,3,5-triazine, 2,4-di-p-toluyl-6- (2-hydroxy-4-octyloxyphenyl) -1, 3,5-triazine, 2,4-di-p-toluyl-6- (2-hydroxy-4-dodecyloxyphenyl) -1,3,5-triazine, 2,4-di-p-toluyl-6 (2-hydroxy-4-benzyloxyphenyl) -1,3,5-triazine, 2,4-di-p-toluyl-6- (2-hydroxy-4- (2-hexyloxyethoxy) phenyl) -1 , 3,5-triazine and the like, and salicylic acid phenyl ester ultraviolet absorbers include para-t-butylphenyl salicylic acid ester, para-octylphenyl salicylic acid ester and the like. The
[0046]
Of these, UV absorbers composed of benzotriazole compounds and hydroxyphenyltriazine compounds which are less volatile are more preferred.
The blending amount of the ultraviolet absorber in the polycarbonate sheet is preferably 0.01 to 20% by weight, more preferably 0.02 to 15% by weight. When the amount is less than 0.01% by weight, the weather resistance effect is small. Conversely, when the amount exceeds 20% by weight, the polycarbonate sheet itself is colored, which is a problem in the polycarbonate sheet characterized by transparency.
[0047]
There is no restriction | limiting about the method of mix | blending this ultraviolet absorber with a polycarbonate. For example, a method of adding and blending an ultraviolet absorber in the polymerization process of polycarbonate, a method of dry blending polycarbonate and an ultraviolet absorber and then kneading under heating and melting, and an ultraviolet absorber during molding of a polycarbonate sheet Examples of methods include side-feeding.
[0048]
Also, there is no limitation on the method of molding the polycarbonate sheet, and the polycarbonate sheet can be molded by an extrusion molding method, a press molding method, an injection molding method or the like, but an extrusion molding method capable of continuously molding a sheet of uniform quality is preferable. .
In the extrusion molding method, powdery or pellet-like polycarbonate raw materials are heated, melted and kneaded in a molding machine by extrusion molding, extruded into a sheet through a T die, etc., and then cooled and solidified using 2 to 4 polishing rolls. To make a sheet. At this time, the resin temperature of the polycarbonate discharged from the molding machine is preferably adjusted to 240 to 290 ° C, more preferably 260 to 280 ° C. If the resin temperature is less than 240 ° C., the load on the molding machine is remarkably increased and molding cannot be performed. Conversely, if molding is performed at a resin temperature exceeding 290 ° C., the UV absorber volatilizes during molding, and coloring or hydrolysis due to heat, etc. Problems occur. The resin temperature discharged from the molding machine can be adjusted during molding by the molding machine heating cylinder temperature and screw rotation speed, and can also be adjusted by changing the screw shape such as L / D, compression ratio, and kneading zone as necessary.
[0049]
In order to form a transparent sheet, it is preferable that hard chrome plating or the like is applied to portions such as a cylinder and screw of a molding machine, a polishing roll, a guide roll and the like that are in direct contact with polycarbonate.
The polycarbonate sheet referred to in the present invention may be a single-layer sheet obtained by forming the above-mentioned polycarbonate alone, or a laminated sheet obtained by stacking a plurality of resins containing the above-described polycarbonate. As the laminated sheet, for example, the surface of the weather-resistant polycarbonate sheet of the present invention is coated with an acrylic resin, another polycarbonate resin, a silicone resin, a fluorine resin, or the like by a method such as a coating method, a film lamination method, or a coextrusion method. Examples of such laminated sheets include those obtained by laminating the weather-resistant polycarbonate sheet of the present invention on an acrylic resin or another polycarbonate resin.
[0050]
The weather-resistant polycarbonate sheet of the present invention can be subjected to secondary processing such as thermoforming, cutting, adhesion, cold bending, printing, etc. in the same manner as a commercially available weather-resistant polycarbonate sheet. In particular, in thermoforming, the weather-resistant polycarbonate sheet of the present invention can be molded at a lower temperature than a commercially available sheet, so that there is almost no loss of the UV absorber blended in the sheet, and it has excellent weather resistance even after thermoforming. Thermoforming here refers to heat-softening a polycarbonate sheet and forming it into a specific shape, such as heat bending, heating curved surface forming, free blow molding, pressure forming, vacuum forming, free press molding, Examples include plug assist vacuum forming, drape forming, vacuum snapback forming, reverse draw forming, and the like.
[0051]
Moreover, the thickness of the weather-resistant polycarbonate sheet in the present invention can be freely designed in the range of 1 to 20 mm.
[0052]
DETAILED DESCRIPTION OF THE INVENTION
The effects of the present invention will be described more specifically with reference to examples and comparative examples.
In addition, evaluation of each item was measured with the following method. Moreover, the complete hydrolysis of polycarbonate and the measuring method of liquid chromatography were performed by the method described in the specification.
(1) Measurement of weight average molecular weight.
[0053]
It was measured by gel permeation chromatography (GPC). (2) Measurement of the UV absorber concentration in the polycarbonate sheet.
The test piece was dissolved in chloroform and subjected to structural analysis by high performance liquid chromatography (model LC-6A, manufactured by Shimadzu Corporation) to determine the spectral peak area of the UV absorber structure portion, From the calibration curve, the residual concentration of the ultraviolet absorber contained in the polycarbonate sheet was determined.
[0054]
(3) Weather resistance
Using a sunshine weather meter manufactured by Suga Test Instruments Co., Ltd., Sunshine Super Long Life Carbon was used, and the test piece was exposed for 1000 hours under a condition of repeating a cycle of 2 hours without rainfall and 18 minutes of rainfall at a constant temperature of 63 ° C.
[0055]
As an evaluation, a change in yellowness before and after exposure was measured according to JIS K7103.
Yellowness (ΔYI) = (Yellowness before exposure) − (Yellowness before exposure)
When the value of yellowing degree (ΔYI) is large, it means that the yellowish color became darker (colored) as a result of the weather resistance test compared to the initial value. You can see clearly.
[0056]
[Example 1]
A continuous process in which a stirring tank type first (A) (B) polymerization vessel, a stirring tank type second polymerization device, a stirring tank type third polymerization device, a perforated plate type first polymerization device, and a perforated plate type second polymerization device are connected. Aromatic polycarbonate was produced. However, the stirred tank first polymerization apparatus was operated batchwise while switching between (A) and (B), and the other polymerization apparatuses were operated continuously. The internal volume of the stirring tank first polymerization vessel (A), (B) is 100 liters, the internal volume of the stirring tank second polymerization vessel and the stirring tank third polymerization vessel is 50 liters, and the stirring blades are both anchor type. is there. The perforated plate type first polymerizer and the perforated plate type second polymerizer are each provided with a perforated plate having 50 holes with a hole diameter of 7.5 mm, and SUS316L wire guides with a diameter of 1 mm pass through each hole. Installed. The height to drop along the guide is 8m. Moreover, each reactor was arrange | positioned so that the length and thickness of piping which connect each reactor might become the minimum.
[0057]
In the stirring tank first polymerization vessel, both (A) and (B) are under the conditions of a temperature of 180 ° C., a normal pressure, and a seal nitrogen gas flow rate of 1 liter / hr. The stirred tank first polymerizer (A) is charged with 80 kg of bisphenol A as an aromatic dihydroxy compound and diphenyl carbonate (a molar ratio of bisphenol A of 1.04) as a carbonic acid diester, and bisphenol A disodium salt as a sodium atom. It added so that it might be set to 20 ppb with respect to preparation bisphenol A, and it melt-mixed for 4 hours, Then, it continuously supplied to the stirring tank 2nd polymerization device at 5 Kg / hr. While supplying from the stirring tank first polymerization vessel (A) to the stirring tank second polymerization vessel, the stirring tank first polymerization vessel (B) is mixed with bisphenol A in the same manner as the stirring tank first polymerization vessel (A). Diphenyl carbonate and bisphenol A disodium salt were melt-mixed and switched to the stirring tank first polymerizer (B) when the stirring tank first polymerizer (A) became empty. Thereafter, in the same manner, the polymerization intermediate was continuously supplied at 5 Kg / hr to the agitation tank second polymerization apparatus while the agitation tank first polymerization apparatus (A) and (B) were switched batchwise.
[0058]
When the internal volume of the second tank in the stirring tank reached 20 liters, the polymerization intermediate was continuously supplied to the third polymerization tank in the stirring tank so as to keep the internal volume of 20 liters constant. The second tank in the stirring tank was under the conditions of a reaction temperature of 230 ° C., a reaction pressure of 100 mmHg, and a nitrogen gas flow rate of 2 liters / hr. When the internal volume of the stirring tank third polymerization vessel reached 20 liters, the polymerization intermediate was continuously supplied to the perforated plate type first polymerization vessel so as to keep the internal volume of 20 liters constant. The third tank in the stirring tank was under the conditions of a reaction temperature of 240 ° C., a reaction pressure of 10 mmHg, and a nitrogen gas flow rate of 2 liters / hr.
[0059]
When the inner volume of the perforated plate type first polymerization vessel reached 10 liters, the polymerization intermediate was continuously supplied to the perforated plate type second polymerization vessel so as to keep the inner volume of 10 liters constant. The perforated plate type first polymerizer was under the conditions of a reaction temperature of 245 ° C., a reaction pressure of 1.5 mmHg, and a nitrogen gas flow rate of 4 liters / hr. When the internal volume of the perforated plate type second polymerization vessel reached 10 liters, the molten polymer was continuously extracted from the nozzle so as to keep the internal volume constant at 10 liters, and pelletized by strand cutting. The perforated plate type second polymerization vessel was under the conditions of a reaction temperature of 245 ° C., a reaction pressure of 0.3 mmHg, and a nitrogen gas flow rate of 2 liters / hr. At this time, Σ (Ki × Ti × Hi) was 0.83.
[0060]
In the polycarbonate thus obtained, the total amount of compounds having a retention time longer than that of bisphenol A is 0.05% by weight, and the total amount A of compounds having a retention time between bisphenol A and diphenyl carbonate (provided that The ratio B / A between the other aromatic dihydroxy compounds used and diphenyl carbonate excluded) and the total amount B of compounds after diphenyl carbonate (excluding the other aromatic dihydroxy compounds used and diphenyl carbonate used) was 0. 2. The polycarbonate had a weight average molecular weight of 26,800.
[0061]
Ultraviolet absorber 0 made of hydroxyphenyltriazine compound comprising 99.9% by weight of the polycarbonate and 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5- (hexyl) oxy-phenol .1% by weight of the dry blend was heated, melted and kneaded through an extruder having a screw diameter of 50 mm, and extruded into a sheet using a sheet die having a width of 300 mm. Next, the sheet-like molten polycarbonate was introduced into a polishing roll having a diameter of 200 mm and cooled and solidified to obtain a polycarbonate sheet.
[0062]
At this time, the resin temperature discharged from the extruder was adjusted to about 260 ° C., the die temperature was adjusted to 250 ° C., and the surface temperature of the polishing roll was adjusted to 130 ° C. The thickness of the sheet was adjusted to 3 mm by controlling the gap between the polishing rolls. The concentration of the ultraviolet absorber remaining in the polycarbonate sheet thus obtained was measured and found to be 0.09% by weight, indicating that there is almost no loss of the ultraviolet absorber during sheet extrusion.
[0063]
As a result of conducting a weather resistance test on this polycarbonate sheet, it was found that the yellowing degree (ΔYI) was 1, and the weather resistance was also good.
Further, as a result of vacuum press molding using the obtained polycarbonate sheet, there was almost no loss of the UV absorber due to thermoforming, the weather resistance was good after thermoforming, and the same performance as before heat molding.
[0064]
[Example 2]
Benzotriazole compound comprising 2,2-methylenebis [4- (1,1,3,3-tetramethylenebutyl) -6- (2H-benzotriazol-2-yl) phenol] as an ultraviolet absorber blended in polycarbonate The same procedure as in Example 1 was performed except that the product was changed to manufactured.
[0065]
The concentration of the ultraviolet absorber remaining in the polycarbonate sheet thus obtained was measured and found to be 0.09% by weight, indicating that there is almost no loss of the ultraviolet absorber during sheet extrusion.
As a result of a weather resistance test of this polycarbonate sheet, it was found that the yellowing degree (ΔYI) was 1, and the weather resistance was as good as in Example 1.
[0066]
Further, as a result of vacuum press molding using the obtained polycarbonate sheet, there was almost no loss of the UV absorber due to thermoforming as in Example 1, and the weather resistance was good after thermoforming and the same performance as before heat molding. there were.
[0067]
[Example 3]
The same procedure as in Example 1 was performed except that the molding conditions were adjusted so that the resin temperature discharged from the extruder was 250 ° C.
As for the state of extrusion molding, although the load on the extruder increased, it seemed that the sheet was formed without any problem. Further, when the concentration of the ultraviolet absorbent remaining in the polycarbonate sheet thus obtained was measured, it was found to be 0.09% by weight, and it was found that there was almost no loss of the ultraviolet absorbent during sheet extrusion as in Example 1. .
[0068]
As a result of conducting a weather resistance test of this polycarbonate sheet, it was found that the yellowing degree (ΔYI) was 1, and the weather resistance was also good.
Further, as a result of vacuum press molding using the obtained polycarbonate sheet, there was almost no loss of the UV absorber due to thermoforming as in Example 1, and the weather resistance was good after thermoforming and the same performance as before heat molding. there were.
[0069]
[Comparative Example 1]
By changing the temperature of each reactor, the total amount of compounds with a retention time longer than bisphenol A was 0.15% by weight, and the total amount of compounds with a retention time between bisphenol A and diphenyl carbonate A (however, The ratio B / A between the aromatic dihydroxy compound and diphenyl carbonate) and the total amount B of compounds after diphenyl carbonate (excluding the other aromatic dihydroxy compounds and diphenyl carbonate used) is 0.95. Evaluation was conducted in the same manner as in Example 1 except that the polycarbonate prepared in the above was used. The weight average molecular weight of the polycarbonate at this time was 26,900.
[0070]
However, if molding is performed under the same molding conditions as in Example 1, the load on the extruder increases and overload stop is repeated, and stable molding cannot be performed. When the molding conditions were adjusted so that the load on the extruder was about the same as in Example 1, the resin temperature discharged from the extruder was 295 ° C.
When the concentration of the UV absorbent remaining in the polycarbonate sheet obtained by sheet molding under the condition that the load on the extruder is about the same as in Example 1 was measured, it was 0.06% by weight. It can be seen that the absorbent is decreasing.
[0071]
When the weather resistance test was conducted on this polycarbonate sheet, it was found that the yellowing degree (ΔYI) was 4, and the effect of blending the ultraviolet absorber was reduced. Further, as a result of performing vacuum press molding in the same manner as in Example 1 using the obtained polycarbonate sheet, volatilization and loss of the UV absorber occurred during heat softening, and the volatilized UV absorber adhered to the press mold. The surface was rough and the weather resistance was further deteriorated even before thermoforming.
[0072]
[Comparative Example 2]
A commercially available polycarbonate produced by the phosgene method having a weight average molecular weight of 26,800 was evaluated in the same manner as in Example 1.
At this time, if the molding is performed under the same conditions as in Example 1, the load on the extruder increases and the overload is stopped, and the molding cannot be performed stably. When the molding conditions were adjusted so that the load on the extruder was approximately the same as in Example 1, the resin temperature discharged from the extruder was 300 ° C.
[0073]
When the concentration of the UV absorbent remaining in the polycarbonate sheet obtained by sheet molding under the condition that the load on the extruder is about the same as in Example 1 was measured, it was 0.03% by weight. It can be seen that the absorbent is decreasing. When this polycarbonate sheet was also subjected to a weather resistance test, the yellowing degree (ΔYI) was 6 and it was found that there was almost no effect of incorporating an ultraviolet absorber.
[0074]
Further, as a result of performing vacuum press molding in the same manner as in Example 1 using the obtained polycarbonate sheet, as in Comparative Example 1, volatilization and loss of the UV absorber occurred during heat softening, and the volatilized UV absorber was converted into a press mold. As a result, the surface of the molded body was rough and the weather resistance was further deteriorated compared to before thermoforming.
[0075]
[Table 1]

[0076]
【The invention's effect】
According to the present invention, it is possible to provide a polycarbonate sheet that maintains weather resistance even after secondary processing such as thermoforming, and a method for producing the weather-resistant polycarbonate sheet that prevents loss of the UV absorber that occurs during molding. It can be used for various purposes.
[0077]
[Explanation of the figure]
[0078]
FIG. 1 is a liquid chromatography chart of a standard compound mixture measured by a method described in the specification.
[0079]
FIG. 2 is a liquid chromatography chart of a completely hydrolyzed polycarbonate measured by the method described in the specification.

Claims (6)

A polycarbonate having a small amount of heterogeneous bonds is a polycarbonate produced by transesterification from an aromatic dihydroxy compound and a carbonic acid diester, and the polycarbonate is completely hydrolyzed and then reverse-phase liquid chromatographed. When the mixture eluent is composed of 0.1% phosphoric acid aqueous solution and the ratio of methanol / 0.1% phosphoric acid aqueous solution starts from 20/80 and is gradient to 100/0, the retention time is the fragrance. The total amount of the compound longer than the group dihydroxy compound (detected with a UV detector with a wavelength of 300 nm and calculated from the peak area using the extinction coefficient of salicylic acid, excluding the carbonic acid diester) was 0. polycarbonate is in the range of 015 to 0.09 wt% Weatherproof polycarbonate sheet ultraviolet absorber is 0.01 to 20 wt% blended Ri. Weatherproof polycarbonate sheet according to claim 1, wherein more than 85 mole% of an aromatic dihydroxy compound characterized in that it is a bisphenol A. Total amount A of compounds with retention time between bisphenol A and diphenyl carbonate (excluding other aromatic dihydroxy compounds and diphenyl carbonate used) and total amount B of compounds after diphenyl carbonate (excluding other used The weather-resistant polycarbonate sheet according to claim 1 or 2, wherein the ratio B / A between the aromatic dihydroxy compound and diphenyl carbonate is 0.8 or less. The weather-resistant polycarbonate sheet according to any one of claims 1 to 3, wherein the ultraviolet absorber comprises a benzotriazole-based compound. The weather-resistant polycarbonate sheet according to any one of claims 1 to 3, wherein the ultraviolet absorber comprises a hydroxyphenyltriazine-based compound. The molding of the weather-resistant polycarbonate sheet according to any one of claims 1 to 5, wherein the resin temperature of the polycarbonate sheet raw material composition made of polycarbonate having a small amount of different bonds is adjusted to 240 to 290 ° C to form a sheet molding machine. A process for producing a weather-resistant polycarbonate sheet, characterized by being extruded from.

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