JP3617571B2 - Polycarbonate resin composition for video equipment and molded article thereof - Google Patents

Description

（式中、Ａｒは二価の芳香族残基であり、例えばフェニレン、ナフチレン、ビフィニレン、ピリジレンや、下記化２で表されるものが挙げられる。）
【００１５】
【化２】

（式中、Ａｒ^１ 及びＡｒ^２ はそれぞれアリレーン基である。例えばフェニレン、ナフチレン、ビフェニレン、ピリジレン等の基を表し、Ｙは下記化３及び化４で表されるアルキレン基または置換アルキレン基である。）
【００１６】
【化３】

【００１７】
【化４】

（式中、Ｒ^１ 、Ｒ^２ 、Ｒ^３ 及びＲ^４ はそれぞれ水素原子、低級アルキル基、シクロアルキル基、アリール基、アラルキル基であって、場合によりハロゲン原子、アルコシ基で置換されていてもよく、ｋは３〜１１の整数であり、化４の水素原子は、低級アルキル基、アリール基、ハロゲンとうで置換されてもよい。）
【００１８】
また、下記化５で示される二価の芳香族残基を共重合体成分として含有していてもよい。
【化５】

（式中、Ａｒ^１ 、Ａｒ^２ は化２と同じ。Ｚは単なる結合、または、−Ｏ−、−ＣＯ−、−Ｓ−、−ＳＯ_２ −、−ＣＯ_２ −、−ＣＯＮ（Ｒ^１ ）−、（Ｒ^１ は前記と同様）等の二価の基である。）
これら二価の芳香族残基の例としては、下記化６及び化７で表されるもの等が挙げられる。
【００１９】
【化６】

【００２０】
【化７】

（式中、Ｒ^５ 及びＲ^６ はそれぞれ水素、ハロゲン、Ｃ_１ 〜Ｃ_１０アルキル基、Ｃ_１ 〜Ｃ_１０アルコキシ基、Ｃ_１ 〜Ｃ_１０シクロアルキル基またはフェニル基である。ｍ及びｎは１〜４の整数で、ｍが２〜４の場合には各Ｒ^５ 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の場合は各Ｒ^６ はそれぞれ同一でも異なるものであってもよい。）
【００２１】
中でも、下記化８で表されるものが好ましい一例である。特に、下記化８をＡｒとする繰り返しユニットを８５モル％以上含むものが好ましい。
【化８】

【００２２】
また、本発明に用いられるポリカーボネート樹脂は、三価以上の芳香族残基を共重合成分として含有していてもよいし、脂肪族または芳香族のエステル成分を共重合成分として含有してもよい。
ポリマー末端の分子構造は特に限定されないが、ヒドロキシ基、アリールカーボネート基、アルキルカーボネート基から選ばれた１種以上の末端基を結合することができる。アリールカーボネート末端基は、下記化９で表され、具体例としては例えば下記化１０が挙げられる。
【００２３】
【化９】

（式中、Ａｒ^３ は一価の芳香族残基で、芳香環は置換されていてもよい。）
【００２４】
【化１０】

【００２５】
アルキルカーボネート末端基は、下記化１１で表され、具体例としては例えば下記化１２等が挙げられる。
【化１１】

（式中、Ｒ^７ は炭素数１〜２０の直鎖もしくは分岐アルキル基）
【００２６】
【化１２】

【００２７】
これらの中で、フェニルカーボネート基、ｐ−ｔ−ブチルフェニルカーボネート基、ｐ−クミルフェニルカーボネート基等が好ましく用いられる。またヒドロキシ基末端と他の末端との比率は１：１００以上であることが好ましく、更に好ましくは１：４０以上である。
本発明に用いられるポリカーボネート樹脂の分子量は特に限定されないが、ポリカーボネート樹脂に含有される加水分解可能な塩素は好ましくは１ｐｐｍ以下、更に好ましくは０．５ｐｐｍ以下である。１ｐｐｍを超える量の塩素がポリカーボネート樹脂中に含有されていると、成形加工時等長時間高温下にさらされることによって着色してしまいポリカーボネート樹脂の特徴である透明感が失われてしまう。
【００２８】
これらポリカーボネート樹脂は公知の方法で製造できる。具体的には、芳香族ジヒドロキシ化合物とカーボネート前駆体とを反応せしめる公知の方法、例えば芳香族ジヒドロキシ化合物とホスゲンを水酸化ナトリウム水溶液及び塩化メチレン溶媒の存在下に反応させる界面重合法（ホスゲン法）、芳香族ジヒドロキシ化合物とジフェニルカーボネートを反応させるエステル交換法（溶融法）、結晶化カーボネートプレポリマーを固相重合する方法（特開平１−１５８０３３号公報、特開平１−２７１４２６号公報、特開平３−６８６２７号公報）等の方法により製造できる。
【００２９】
本発明に用いられる光吸収化合物は、２５０〜３０００ｎｍの波長領域に於ける少なくとも一箇所以上の波長又は波長帯での吸光度が０．０１以上である物、すなわち２５０〜３０００ｎｍの波長領域での吸光度スペクトルに於いて０．０１以上となる線状又は任意の幅を有するスペクトル構造を一箇所以上示す物から選ばれて使用される。光吸収化合物の形態は、ポリカーボネート樹脂中に均一に分散しかつ該樹脂組成物の光学特性が一様となるために、２５℃に於いて粉末状であることが好ましい。また、光吸収化合物粉末の大きさも組成物の光学特性に影響を及ぼすため、粉末の重量平均粒子径が０．０１〜５０μｍの範囲にあることが好ましい。
【００３０】
具体的には、無機系顔料として硫酸バリウム、炭酸カルシウム、タルク、クレー、アルミナホワイト、ホワイトカーボン、炭酸鉛、塩基性炭酸鉛、酸化亜鉛、硫化亜鉛、二酸化チタン、含硫黄ナトリウムアルミノシリケート系顔料、フェロシアン化鉄、フェロシアン化第二鉄、アルミン酸コバルト、酸化クロム、含水酸化クロム、クロム酸鉛、塩基性クロム酸鉛、硫酸鉛、モリブデン酸鉛、硫化カドミウム、セレン化カドミウム、炭酸カドミウム、酸化鉄、酸化第二鉄、酸化第一銅、塩基性クロム酸亜鉛カリウム、ストロンチウムクロメート系顔料、カーボンブラック等、有機系顔料としてアゾレーキ顔料、不溶性アゾ顔料、縮合アゾ顔料、フタロシアニン顔料、キナクリドン顔料、イソインドリノン顔料、バット系顔料（アントラピリミジン、フラバンスロン、臭素化アンサンスロン、ペリノン、ペリレン、チオインジゴ、塩素化イソビオランスロン、インダンスロン、オキサジン、アリザリン）等、染料としてアゾ系染料、ビスアゾ系染料、トリスアゾ系染料、アントラキノン系染料、トリフェニルメタン系染料、ポリメチン系染料、インジゴイド系染料、スチルベン系染料、ピラゾロン系染料、ナフタジン系染料等が挙げられる。
【００３１】
特に好ましくは、バナジウム、クロム、マンガン、鉄、コバルト、ニッケル、銅、亜鉛等の遷移金属、及びカルシウム、ストロンチウム、バリウム等のアルカリ土類金属の中から選ばれた少なくとも一種以上の金属を構造中に含む化合物が用いられる。これらの光吸収化合物は単独で使用しても良いし、複数混合しても好ましく使用できる。
【００３２】
光吸収化合物の配合量は特に限定されないが、好ましくはポリカーボネート樹脂１００重量部に対して０．０００１〜５０重量部、より好ましくは０．０００１〜１０重量部の範囲である。ポリカーボネート樹脂１００重量部に対して０．０００１〜１０重量部であれば、ポリカーボネート樹脂中への分散が容易にかつ均一にできる点で好ましい。
【００３３】
本発明に用いられる化合物の吸光度とは、下記（１）のＡで定義される値であり、図２にその測定原理を示している。光源６から発せられ試料７に入射する光線６１の光量をＩ_０ とすると、試料から出射する光線７１は光量Ｉに減じる。この光量変化率Ｉ／Ｉ_０ を、式（１）に従って計算して求めた値Ａが吸光度である。光源から発せられた光線の波長を分光する装置を備えた一般の分光測定器を用いれば、各波長に於ける吸光度が求められる。
【数１】
Ａ＝−ｌｏｇ（Ｉ／Ｉ_０ ） ・・・（１）
【００３４】
測定する試料の形態や波長領域によって吸光度の測定手法は異なるが、粉末状試料の吸光度を測定する場合には、試料中を拡散して透過する光線成分も検出する必要があるため、例えばＪＩＳ−Ｚ８７２２に示される光学測定系を利用することができる。
本発明に於ける樹脂組成物の製造方法は、ポリカーボネート樹脂中に前記の化合物が均一に分散する方法であれば特に制限されないが、例えば重合性単量体もしくは部分重合した重合性単量体のシラップ中に該化合物を分散させて重合する方法、あらかじめ重合しておいたポリカーボネート樹脂に該化合物を混合し、溶融混練して押出し造粒する方法等がある。
【００３５】
本発明に於いては、樹脂組成物及びその成形体の光学特性及び機械的熱的特性を損なわない範囲に於いて他の成分、例えば補強剤、充填剤、離型剤、熱安定剤、酸化防止剤、核剤、光安定剤、紫外線吸収剤、可塑剤等を、樹脂組成物の製造時やその成形時など任意の過程において含有させることができる。
本発明に於ける樹脂組成物は任意の形状に成形し、各種映像機器用部品として使用することができる。樹脂成形体の構造は、ポリカーボネート樹脂と化合物からなるポリカーボネート樹脂組成物を成形した物であれば、一種類の樹脂組成物から成る単層構造又は二種類以上の樹脂組成物から成る多層構造のいずれでも良い。
【００３６】
成形体の形状とその成形方法は特に限定されるものではないが、例えばＴダイによる押出シート成形法を用いれば平滑、波形、プリズム形のシート状成形体を得ることができる。当該シート状成形体を真空成形、圧空成形、スタンパブル成形により二次加工しても良い。映像機器の部品形状が複雑な場合には、環状ダイによる異形押出成形、ブロー成形、射出成形、圧縮成形等により所望の形状の成形体を得ることができる。
【００３７】
また、多層構造を有する成形体を得るためには、二種類以上の樹脂組成物を同時に溶融押出する共押出成形方法、二種類の樹脂組成物の一方を単層押出しながら予め成形された他方をラミネートする方法、二種類の樹脂組成物を予め成形した後プレスして熱圧着する方法、連続的に重ねて貼り合わせる方法、真空成形、圧空成形時に積層する方法等がある。
本発明に於いて、全光線透過率の測定は、樹脂組成物又はその成形体を０．１〜３０ｍｍ、より好ましくは０．５〜１０ｍｍの範囲の厚みを有するシート状物にて、ＪＩＳ−Ｋ７１０５法に準じた市販の測定機を用いて行うことができる。全光線透過率が５０〜９０％であれば、映像機器の本来の輝度を低下させることがない点で好ましい。
【００３８】
また、分光光線透過率の測定は、樹脂組成物又はその成形体を０．１〜３０ｍｍ、より好ましくは０．５〜１０ｍｍの範囲の厚みを有するシート状物にて、市販の分光測定機を用いて行うことができる。４５０〜６５０ｎｍの可視光波長領域に於ける分光光線透過率が５０〜８５％であれば、カラー映像の３原色である赤、緑、青色の波長帯の光線を有効に透過することができる点で好ましい。また、波長８００ｎｍに於ける分光光線透過率が２０％以下であれば、映像機器からの赤外からマイクロ波領域の電磁波放射を防ぐことができ好ましい。
【００３９】
以上のようにして製造された、ポリカーボネート樹脂と２５０〜３０００ｎｍの波長領域に於ける少なくとも一箇所以上の波長又は波長帯での吸光度が０．０１以上である少なくとも一種以上の光吸収化合物からなるポリカーボネート樹脂組成物を、シート状物に成形した時の全光線透過率が５０〜９０％の範囲にあり、かつ４５０〜６５０ｎｍの可視光波長領域に於ける分光光線透過率が５０〜８５％の範囲内にあることを同時に満足する場合に、本発明は達成される。また、ポリカーボネート樹脂と少なくとも一種以上の上記光吸収化合物からなるポリカーボネート樹脂組成物を、シート状物に成形した時の波長８００ｎｍに於ける分光光線透過率が２０％以下である場合は、本発明は更に好ましく達成される。また、これらの樹脂組成物及び任意の形状に成形した成形体は、映像表示部の前面に設置されるプラズマディスプレイ用成形体として非常に有用である。
【００４０】
【実施例】
以下、実施例、および比較例を用いて本発明を具体的に説明する。なお、各実施例、比較例で用いた評価及び試験方法は次の通りである。
（１）吸光度の測定：
粉末試料を２枚の石英ガラスで１ｍｍの間隔を持たせて挟んだ状態にし、島津製作所社製自記分光光度計ＵＶ−３１００ＰＣ型（商品名）を用いて２２０〜２０００ｎｍの範囲にて光吸収スペクトルを測定する。２０００〜３０００ｎｍの範囲の吸収スペクトルは、粉末試料を臭化カリウム粉末と混合、粉砕して１ｍｍ厚の錠剤状に固めた状態にし、日本分光社製分光測定器ＩＲ−７００型（商品名）を用いて測定する。得られたスペクトルに於いて、最大ピークを示す波長帯での吸光度を前記式（１）に従って求める。
【００４１】
（２）光線透過率の評価：
樹脂試験片を島津製作所社製自記分光光度計ＵＶ−３１００ＰＣ型に設置し、３００〜９００ｎｍの波長範囲にて透過スペクトルを測定し、測定チャートから４５０〜６５０ｎｍに於ける分光光線透過率を読みとる。全光線透過率は、ＪＩＳ−Ｋ７１０５に準じた日本電色工業社製１００１−ＤＰ型（商品名）ヘイズメーターを用いて測定する。
【００４２】
（３）映像コントラストの評価：
平滑シート状の樹脂成形体を、市販のプラズマディスプレイパネル（富士通ゼネラル社製 プラズマビジョンＭ２１ ＰＤＳ−２１２３型：商品名）の前面に設置し、映像のコントラストを目視判定した。◎は良好な場合、△は効果が認められない場合、×は使用できないと判断される場合を示す。
【００４３】
（４）映像表示部とハウジング部との一体感の評価：
平滑シート状の樹脂成形体を、市販のプラズマディスプレイパネル（富士通ゼネラル社製 プラズマビジョンＭ２１ ＰＤＳ−２１２３型）の前面に設置し、映像のコントラストを目視判定した。◎は良好な場合、△は効果が認められない場合、×は使用できないと判断される場合を示す。
（５）荷重たわみ温度の評価：
平滑シート状の樹脂成形体の耐熱性の評価としてＪＩＳ−Ｋ７２０７ Ａ法に準拠した荷重たわみ温度を測定した。
【００４４】
（実施例１、実施例２）
ポリカーボネート樹脂（商品名：パンライトＫ１３００、帝人化成社製）と、上記（１）の方法により測定した吸光度が０．０２以上を示す光吸収化合物（ニッケル系有機化合物、商品名：ＳＩＲ−１５９、三井東圧染料社製）を表１に示す濃度で配合し、ヘンシェルミキサーでブレンドした後ベント付き押出機４０ｍｍφで樹脂温度２９０℃にてペレット化して樹脂組成物を得る。得られたペレットを押出機（スクリュー径５０ｍｍφ、Ｌ／Ｄ＝３２、単軸）、マルチマニホールドダイ、及びポリッシングロール３本から成るユニットを用いて押出シート成形を行い、幅３００ｍｍの単層シートを作成する。積層シートを作成する場合は、第二の押出機（スクリュー径２５ｍｍφ、Ｌ／Ｄ＝３２、単軸）を組み合わせて共押出シート成形を行い、同様に幅３００ｍｍの積層シートを得ることができる。シートの厚みはポリッシングロールのクリアランスで２．０ｍｍを目標に調整する。積層シートの積層部の厚みは、二機の押出機の吐出量バランスで調整する。得られたシートを試験片として上記（２）〜（５）の評価を行う。結果を表２に示す。
【００４５】
実施例１では、試験片の全光線透過率が５９％で、４５０〜６５０ｎｍの分光光線透過率が５９〜６８％を示し好ましい結果を得る。更に、８００ｎｍに於ける分光光線透過率も２％を示し非常に好ましく、プラズマディスプレイ前面に設置した場合、画像のコントラストの向上及びハウジング部との一体感が認められ非常に好ましい。また荷重たわみ温度も１４０℃あり好ましい。
【００４６】
実施例２では、試験片の全光線透過率が７２％で、４５０〜６５０ｎｍの分光光線透過率が７３〜７８％を示し好ましい結果を得る。更に、８００ｎｍに於ける分光光線透過率も７％を示し非常に好ましい。また、プラズマディスプレイ前面に設置する材料として映像コントラスト及びハウジング部との一体感の効果が認められ好ましい。
【００４７】
（実施例３）
各々の吸光度が全て０．０３以上を示す化合物３種類を、表１に示す配合濃度で用いた以外はすべて実施例１と同じ条件で試験片を作成し、（２）〜（５）の評価を行う。評価結果を表２に示す。
で、４５０〜６５０ｎｍの分光光線透過率が６０〜６９％を示し好ましい結果を得る。８００ｎｍに於ける分光光線透過率は２０％以下を示さないが、プラズマディスプレイ前面に設置した場合、映像コントラストの向上及びハウジング部との一体感が認められ好ましい。
【００４８】
（比較例１〜４）
化合物の種類及び配合濃度を表１に従って変えた以外はすべて実施例１と同じ条件で試験片を作成し、（２）〜（５）の評価を行う。用いた化合物の各々の吸光度は表１に示す通りである。評価結果を表２に示す。
比較例１〜２では、試験片の４５０〜６５０ｎｍの分光光線透過率が８５％を超え好ましくない。また、プラズマディスプレイ前面に設置した場合、特に映像のコントラストの向上が認められない点で好ましくない。
【００４９】
比較例３では、試験片の全光線透過率は７５％を示すが、４５０〜５００ｎｍの範囲で分光光線透過率がほぼ０％を示し好ましくない。また、プラズマディスプレイ前面に設置した場合、特に電源を切った後に画面が浮き出て見えるため効果はないと判断でき好ましくない。
比較例４では、試験片の全光線透過率は５２％を示すが、４５０〜６５０ｎｍの分光光線透過率は３６％を示し好ましくない。また、不透明性を示すためプラズマディスプレイの前面材料として使用できない。
【００５０】
（比較例５）
使用した樹脂をポリカーボネート樹脂から現在よく用いられているメタクリル樹脂（商品名：デルパウダ７０Ｈ、旭化成工業製）に変えた以外は実施例１と同様に行った。光学特性としては、試験片の全光線透過率が６３％で、４５０〜６５０ｎｍの分光光線透過率が６２〜７１％を示し好ましい結果を得、更に８００ｎｍに於ける分光光線透過率も２％を示し非常に好ましい。またプラズマディスプレイ前面に設置した場合、画像のコントラストの向上及びハウジング部との一体感が認められ非常に好ましいが、耐熱性が実施例１に比べると４０℃も低く好ましくない。
【００５１】
【表１】

【００５２】
【表２】

【００５３】
【発明の効果】
本発明によって得られる樹脂組成物及び成形体は、光の散乱や拡散による光量損失が小さく４５０〜６５０ｎｍの波長帯の光線を有効に透過し、映像コントラストが高く、機器の電源を切った時にハウジング部と映像表示部とに一体感があり、かつ従来品に比べ耐熱性も向上しており、各種映像機器の映像表示部の前面に設置する材料として極めて有用である。
【図面の簡単な説明】
【図１】本発明により得られる樹脂成形体と、２種類のプラズマディスプレイとの構成について模式的に表現した図である。
【図２】本発明に用いられる化合物の吸光度の測定原理を模式的に示した図である。
【符号の説明】
１ プラズマ
１１ 紫外線
１２ 可視光線
２ ガラス基板
２１ 表示電極
２２ アドレス電極
２３ カソード電極
２４ アノード電極
２５ 隔壁
３１ 誘電体
３２ 保護層
３３ 抵抗
３４ 絶縁体
４ 蛍光体
５ 成形体材料
６ 光源
６１ 試料へ入射する光線
７ 測定する試料
７１ 試料から出射する光線[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a polycarbonate resin composition having a controlled spectral light transmittance in a specific wavelength region and a molded product thereof. More specifically, the present invention relates to a television, an automobile navigation system, a mobile communication device such as a mobile phone and a mobile terminal, an AV device, The present invention relates to a polycarbonate resin molded body installed on the front surface of a video display unit of various devices such as OA devices, word processors, and personal computers.
[0002]
[Prior art]
In recent years, in video equipment typified by color television, in addition to the conventional direct-view television using a CRT, a plasma display or the like has been developed due to market demands for higher definition and larger screens of projected images. Televisions such as the light-emitting panel method used, the non-light-emitting panel method using a liquid crystal display, and the rear projection method with a built-in video projector are entering the market.
[0003]
As video equipment specifications and component structures are diversified, the color from visible to infrared or microwave range depends on the structural factors of the light source or discharge part that serves as the image signal source or each pixel part that constitutes the image. Light rays other than the wavelength bands of the three primary colors (red, green, and blue) of the image are emitted, causing problems such as screen flickering, uneven color tone, and malfunction of the device due to electromagnetic radiation.
[0004]
If these problems are solved by adjusting the electrical signals on the drive circuit of the video equipment, secondary problems such as a decrease in the overall brightness of the screen and a decrease in the color resolution occur. A function to efficiently transmit light in all the wavelength bands of red, green, and blue, particularly in the 450 to 650 nm wavelength band, which has high human visibility, and has little light loss due to light scattering and diffusion. It is desired to provide a material having
[0005]
Conventionally, in order to solve such a problem, it has been proposed to install a material having an optical filter function that prevents light in a specific wavelength band from passing through in a video device. For example, JP-A- 58-160941 discloses a material containing a neodymium compound of a carboxylic acid in a methacrylic resin, JP-A- 4-72361 discloses a material containing a neodymium compound in a transparent resin, JP-A-5-179147. The publication discloses a material containing an erbium compound in a transparent resin.
[0006]
[Problems to be solved by the invention]
However, the materials obtained by these methods can only absorb light in a very narrow wavelength band, and light in the wavelength bands of red, green and blue, which are the three primary colors of color images, particularly in the wavelength range of 450 to 650 nm. It cannot be said that the material has a function of efficiently transmitting the light beam. However, simply increasing the light transmittance in the visible region is not preferable because the ambient light from the surrounding lighting overlaps with the image and lowers the contrast, and when the image equipment is turned off, the image is displayed on the housing. A new problem arises that the part is raised and is not preferable.
[0007]
In addition, methacrylic resins having excellent optical properties have been often used as the above materials. However, as the specifications of video equipment and the component structures constituting it are diversified, each of the light source or discharge unit or image constituting the image signal source is used. Due to the structural factors of the pixel portion, the material itself is exposed to a high temperature, and thus heat resistance is required.
The object of the present invention is that the loss of light quantity due to light scattering and diffusion is small, and light in the wavelength band of 450 to 650 nm is effectively transmitted, the image contrast is high, and the housing part and the image display part are turned off when the device is turned off. The object is to provide a material with a sense of unity and improved heat resistance.
[0008]
[Means for Solving the Problems]
As a result of intensive studies to solve the above problems, the present inventors have found that a compound having an optically active, that is, light-absorbing property, in a specific wavelength region of a light beam emitted from a light source or a discharge portion serving as an image signal source is resin. It was found that a material satisfying the required optical properties could be created by dispersing the resin in the inside, and the present invention was completed by using a polycarbonate resin having excellent heat resistance instead of the conventionally used methacrylic resin. .
[0009]
That is, the present invention is a polycarbonate resin composition comprising a polycarbonate resin and at least one light absorbing compound having an absorbance of 0.01 or more in a wavelength region of 250 to 3000 nm, wherein the composition is formed into a sheet-like material. A polycarbonate resin composition for video equipment having a total light transmittance of 50 to 90% when molded and a spectral light transmittance in the range of 50 to 85% in a visible light wavelength region of 450 to 650 nm, and A molded body obtained by molding the composition into an arbitrary shape.
[0010]
Also, a polycarbonate resin composition comprising a polycarbonate resin and at least one or more of the above light-absorbing compounds, the spectral light transmittance at a wavelength of 800 nm when the composition is molded into a sheet is 20% or less. According to the present invention, a polycarbonate resin composition for video equipment, and a molded body obtained by molding the composition into an arbitrary shape can prevent electromagnetic wave radiation from the infrared to the microwave region from the video equipment. Is more preferable.
[0011]
Further, a polycarbonate resin composition comprising a polycarbonate resin and at least one or more of the above light-absorbing compounds, wherein the total light transmittance when the composition is formed into a sheet-like material is 50 to 90% and 450 to 650 nm. A polycarbonate resin composition for video equipment having a spectral light transmittance in a range of 50 to 85% in a visible light wavelength region and a spectral light transmittance at a wavelength of 800 nm of 20% or less. , And a molded product obtained by molding the composition into an arbitrary shape, which is more preferable for the present invention.
[0012]
Furthermore, it is a molded article for plasma display installed on the front surface of the video display section, characterized by molding the above resin composition.
The structure of two types of plasma displays and the molded product obtained by the present invention will be described with reference to FIG. Three types of visible light 12 emitted when the three types of phosphors 4 are optically excited by the ultraviolet rays 11 generated by the plasma 1 and relaxed in energy become the three primary colors of the image. The molded body material 5 installed in front of the image display surface on the observer side is a molded body obtained by the present invention.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
The polycarbonate resin used for this invention has the principal chain which consists of a repeating unit represented by following Chemical formula 1.
[0014]
[Chemical 1]

(In the formula, Ar is a divalent aromatic residue, and examples thereof include phenylene, naphthylene, bifinylene, pyridylene, and those represented by the following chemical formula 2.)
[0015]
[Chemical formula 2]

(In the formula, Ar ¹ and Ar ² are each an arylene group. For example, they represent groups such as phenylene, naphthylene, biphenylene, pyridylene, and Y represents an alkylene group or a substituted alkylene group represented by the following chemical formulas 3 and 4. .)
[0016]
[Chemical 3]

[0017]
[Formula 4]

Wherein R ¹ , R ² , R ³ and R ⁴ are each a hydrogen atom, a lower alkyl group, a cycloalkyl group, an aryl group or an aralkyl group, optionally substituted with a halogen atom or an alkoxy group. Well, k is an integer of 3 to 11, and the hydrogen atom in Chemical Formula 4 may be substituted with a lower alkyl group, an aryl group, or a halogen.
[0018]
Moreover, you may contain the bivalent aromatic residue shown by following Chemical formula 5 as a copolymer component.
[Chemical formula 5]

(Wherein Ar ¹ and Ar ² are the same as those in Chemical Formula 2. Z is a simple bond, or —O—, —CO—, —S—, —SO ₂ —, —CO ₂ —, —CON (R ¹ ). -Or a divalent group such as (R ¹ is the same as above).
Examples of these divalent aromatic residues include those represented by the following chemical formulas 6 and 7.
[0019]
[Chemical 6]

[0020]
[Chemical 7]

Wherein R ⁵ and R ⁶ are each hydrogen, halogen, C ₁ -C ₁₀ alkyl group, C ₁ -C ₁₀ alkoxy group, C ₁ -C ₁₀ cycloalkyl group or phenyl group. Each of R ⁵ may be the same or different when m is 2 to 4, and each of R ⁶ is the same or different when n is 2 to 4. May be.)
[0021]
Especially, what is represented by following Chemical formula 8 is a preferable example. In particular, those containing 85 mol% or more of a repeating unit in which the following chemical formula 8 is represented by Ar are preferable.
[Chemical 8]

[0022]
The polycarbonate resin used in the present invention may contain a trivalent or higher aromatic residue as a copolymerization component, or may contain an aliphatic or aromatic ester component as a copolymerization component. .
The molecular structure of the polymer terminal is not particularly limited, but one or more terminal groups selected from a hydroxy group, an aryl carbonate group, and an alkyl carbonate group can be bonded. The aryl carbonate terminal group is represented by the following chemical formula 9, and specific examples thereof include the chemical formula 10 below.
[0023]
[Chemical 9]

(In the formula, Ar ³ is a monovalent aromatic residue, and the aromatic ring may be substituted.)
[0024]
[Chemical Formula 10]

[0025]
The alkyl carbonate terminal group is represented by the following chemical formula 11, and specific examples thereof include the chemical formula 12 below.
Embedded image

(Wherein R ⁷ is a linear or branched alkyl group having 1 to 20 carbon atoms)
[0026]
Embedded image

[0027]
Among these, a phenyl carbonate group, a pt-butylphenyl carbonate group, a p-cumylphenyl carbonate group, and the like are preferably used. Further, the ratio of the hydroxyl group terminal to the other terminal is preferably 1: 100 or more, more preferably 1:40 or more.
The molecular weight of the polycarbonate resin used in the present invention is not particularly limited, but the hydrolyzable chlorine contained in the polycarbonate resin is preferably 1 ppm or less, more preferably 0.5 ppm or less. When the amount of chlorine exceeding 1 ppm is contained in the polycarbonate resin, it is colored by being exposed to a high temperature for a long time, such as during molding, and the transparency characteristic of the polycarbonate resin is lost.
[0028]
These polycarbonate resins can be produced by a known method. Specifically, a known method of reacting an aromatic dihydroxy compound and a carbonate precursor, for example, an interfacial polymerization method in which an aromatic dihydroxy compound and phosgene are reacted in the presence of an aqueous sodium hydroxide solution and a methylene chloride solvent (phosgene method). A transesterification method in which an aromatic dihydroxy compound and diphenyl carbonate are reacted (melting method), and a method in which a crystallized carbonate prepolymer is solid-phase polymerized (Japanese Patent Laid-Open Nos. 1-158033, 1-271426, and 3) -68627) and the like.
[0029]
The light absorbing compound used in the present invention has an absorbance of 0.01 or more at a wavelength or wavelength band of at least one place in a wavelength region of 250 to 3000 nm, that is, an absorbance in a wavelength region of 250 to 3000 nm. It is selected from those showing one or more spectral structures having a linear or arbitrary width of 0.01 or more in the spectrum. The light absorbing compound is preferably in the form of a powder at 25 ° C. so that it is uniformly dispersed in the polycarbonate resin and the optical properties of the resin composition are uniform. Further, since the size of the light absorbing compound powder also affects the optical properties of the composition, the weight average particle diameter of the powder is preferably in the range of 0.01 to 50 μm.
[0030]
Specifically, barium sulfate, calcium carbonate, talc, clay, alumina white, white carbon, lead carbonate, basic lead carbonate, zinc oxide, zinc sulfide, titanium dioxide, sulfur-containing sodium aluminosilicate pigments as inorganic pigments, Ferric ferrocyanide, ferric ferrocyanide, cobalt aluminate, chromium oxide, hydrous chromium oxide, lead chromate, basic lead chromate, lead sulfate, lead molybdate, cadmium sulfide, cadmium selenide, cadmium carbonate, Iron oxide, ferric oxide, cuprous oxide, basic zinc potassium chromate, strontium chromate pigment, carbon black, etc., organic pigments such as azo lake pigments, insoluble azo pigments, condensed azo pigments, phthalocyanine pigments, quinacridone pigments, Isoindolinone pigments, vat pigments (anthra pyrimidine Flavanthrone, brominated ansanthrone, perinone, perylene, thioindigo, chlorinated isoviolanthrone, indanthrone, oxazine, alizarin), etc., azo dyes, bisazo dyes, trisazo dyes, anthraquinone dyes, Examples include triphenylmethane dyes, polymethine dyes, indigoid dyes, stilbene dyes, pyrazolone dyes, and naphthazine dyes.
[0031]
Particularly preferably, the structure contains at least one metal selected from transition metals such as vanadium, chromium, manganese, iron, cobalt, nickel, copper, and zinc, and alkaline earth metals such as calcium, strontium, and barium. Are used. These light-absorbing compounds may be used alone, or may be preferably used by mixing a plurality of them.
[0032]
Although the compounding quantity of a light absorption compound is not specifically limited, Preferably it is 0.0001-50 weight part with respect to 100 weight part of polycarbonate resin, More preferably, it is the range of 0.0001-10 weight part. If it is 0.0001-10 weight part with respect to 100 weight part of polycarbonate resin, it is preferable at the point which can disperse | distribute in polycarbonate resin easily and uniformly.
[0033]
The absorbance of the compound used in the present invention is a value defined by A in (1) below, and FIG. 2 shows the measurement principle. If the light quantity of the light beam 61 emitted from the light source 6 and incident on the sample 7 is I ₀ , the light beam 71 emitted from the sample is reduced to the light quantity I. The value A obtained by calculating the light quantity change rate I / I _{0 according} to the equation (1) is the absorbance. If a general spectrophotometer equipped with a device that splits the wavelength of light emitted from a light source is used, the absorbance at each wavelength can be obtained.
[Expression 1]
A = −log (I / I ₀ ) (1)
[0034]
Although the measurement method of absorbance varies depending on the form and wavelength region of the sample to be measured, when measuring the absorbance of a powdered sample, it is necessary to detect the light component that diffuses and transmits through the sample. For example, JIS- An optical measurement system shown in Z8722 can be used.
The method for producing the resin composition in the present invention is not particularly limited as long as the compound is uniformly dispersed in the polycarbonate resin. For example, a polymerizable monomer or a partially polymerized polymerizable monomer is used. There are a method in which the compound is dispersed in syrup for polymerization, a method in which the compound is mixed with a previously polymerized polycarbonate resin, a melt kneading, extrusion granulation, and the like.
[0035]
In the present invention, other components such as a reinforcing agent, a filler, a release agent, a thermal stabilizer, an oxidation agent are used as long as the optical properties and mechanical thermal properties of the resin composition and the molded product thereof are not impaired. An inhibitor, a nucleating agent, a light stabilizer, an ultraviolet absorber, a plasticizer, and the like can be contained in an arbitrary process such as when the resin composition is produced or molded.
The resin composition in the present invention can be molded into an arbitrary shape and used as various parts for video equipment. The structure of the resin molded body is either a single-layer structure composed of one type of resin composition or a multilayer structure composed of two or more types of resin compositions as long as it is a molded product of a polycarbonate resin composition composed of a polycarbonate resin and a compound. But it ’s okay.
[0036]
The shape of the molded body and its molding method are not particularly limited. For example, if an extrusion sheet molding method using a T-die is used, a smooth, corrugated, prism-shaped sheet-shaped molded body can be obtained. The sheet-like molded body may be subjected to secondary processing by vacuum forming, pressure forming, or stampable forming. When the shape of the parts of the video equipment is complicated, a molded body having a desired shape can be obtained by profile extrusion molding using an annular die, blow molding, injection molding, compression molding, or the like.
[0037]
Moreover, in order to obtain a molded body having a multilayer structure, a co-extrusion molding method in which two or more types of resin compositions are melt-extruded at the same time, and the other molded in advance while one of the two types of resin compositions is extruded as a single layer. There are a laminating method, a method in which two types of resin compositions are preliminarily molded, followed by pressing and thermocompression bonding, a method of continuously laminating and bonding, a method of vacuum molding, a method of laminating at the time of pressure forming, and the like.
In the present invention, the total light transmittance is measured by using a resin composition or a molded product thereof in a sheet form having a thickness in the range of 0.1 to 30 mm, more preferably 0.5 to 10 mm. It can be carried out using a commercially available measuring machine according to the K7105 method. A total light transmittance of 50 to 90% is preferable in that the original luminance of the video equipment is not lowered.
[0038]
Further, the measurement of the spectral light transmittance is carried out using a commercially available spectrophotometer with a sheet-like material having a thickness in the range of 0.1 to 30 mm, more preferably 0.5 to 10 mm. Can be used. If the spectral light transmittance in the visible light wavelength region of 450 to 650 nm is 50 to 85%, light in the red, green and blue wavelength bands, which are the three primary colors of the color image, can be effectively transmitted. Is preferable. Further, if the spectral light transmittance at a wavelength of 800 nm is 20% or less, it is preferable because electromagnetic radiation in the microwave region from the infrared from the video equipment can be prevented.
[0039]
A polycarbonate comprising the polycarbonate resin and at least one light-absorbing compound having an absorbance of 0.01 or more in at least one wavelength or wavelength band in the wavelength region of 250 to 3000 nm, produced as described above. When the resin composition is formed into a sheet-like material, the total light transmittance is in the range of 50 to 90%, and the spectral light transmittance in the visible light wavelength region of 450 to 650 nm is in the range of 50 to 85%. The present invention is achieved when it is simultaneously satisfied to be within. Further, when the spectral resin transmittance at a wavelength of 800 nm when a polycarbonate resin composition comprising a polycarbonate resin and at least one light absorbing compound is molded into a sheet is 20% or less, the present invention is It is more preferably achieved. In addition, these resin compositions and molded articles molded into an arbitrary shape are very useful as molded articles for plasma display installed on the front surface of the video display unit.
[0040]
【Example】
Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. In addition, the evaluation and test method used by each Example and the comparative example are as follows.
(1) Measurement of absorbance:
A powder sample is sandwiched between two quartz glasses with a spacing of 1 mm, and a light absorption spectrum in the range of 220 to 2000 nm using a self-recording spectrophotometer UV-3100PC type (trade name) manufactured by Shimadzu Corporation. Measure. Absorption spectrum in the range of 2000 to 3000 nm is obtained by mixing a powder sample with potassium bromide powder, crushing it into a 1 mm thick tablet, and using a spectrophotometer IR-700 (trade name) manufactured by JASCO Corporation. Use to measure. In the obtained spectrum, the absorbance in the wavelength band showing the maximum peak is determined according to the above formula (1).
[0041]
(2) Evaluation of light transmittance:
The resin test piece is set in a self-recording spectrophotometer UV-3100PC type manufactured by Shimadzu Corporation, the transmission spectrum is measured in the wavelength range of 300 to 900 nm, and the spectral light transmittance at 450 to 650 nm is read from the measurement chart. The total light transmittance is measured using a 1001-DP type (trade name) haze meter manufactured by Nippon Denshoku Industries Co., Ltd. according to JIS-K7105.
[0042]
(3) Evaluation of image contrast:
The smooth sheet-shaped resin molding was placed on the front of a commercially available plasma display panel (Plasma Vision M21 PDS-2123 type: product name, manufactured by Fujitsu General Limited), and the contrast of the image was visually determined. The symbol 良好 indicates a favorable case, the symbol △ indicates a case where no effect is observed, and a symbol X indicates a case where it is determined that it cannot be used.
[0043]
(4) Evaluation of unity between the video display unit and the housing unit:
The smooth sheet-shaped resin molded body was placed on the front of a commercially available plasma display panel (Plasma Vision M21 PDS-2123 manufactured by Fujitsu General Limited), and the contrast of the image was visually determined. The symbol 良好 indicates a favorable case, the symbol △ indicates a case where no effect is observed, and a symbol X indicates a case where it is determined that it cannot be used.
(5) Evaluation of deflection temperature under load:
As an evaluation of the heat resistance of the smooth sheet-shaped resin molded product, the deflection temperature under load in accordance with JIS-K7207 A method was measured.
[0044]
(Example 1, Example 2)
A polycarbonate resin (trade name: Panlite K1300, manufactured by Teijin Chemicals Ltd.) and a light absorbing compound (nickel organic compound, trade name: SIR-159) having an absorbance measured by the method of (1) above of 0.02 or more. (Mitsui Toatsu Dye Co., Ltd.) was blended at the concentrations shown in Table 1, blended with a Henschel mixer, and pelletized at a resin temperature of 290 ° C. with a vented extruder 40 mmφ to obtain a resin composition. The obtained pellets were extruded using a unit consisting of an extruder (screw diameter 50 mmφ, L / D = 32, single axis), multi-manifold die, and three polishing rolls, and a single layer sheet having a width of 300 mm was formed. create. In the case of producing a laminated sheet, a coextruded sheet is formed by combining a second extruder (screw diameter 25 mmφ, L / D = 32, uniaxial), and a laminated sheet having a width of 300 mm can be obtained in the same manner. The thickness of the sheet is adjusted with a polishing roll clearance of 2.0 mm as a target. The thickness of the laminated portion of the laminated sheet is adjusted by the discharge amount balance of the two extruders. Evaluation of said (2)-(5) is performed by using the obtained sheet | seat as a test piece. The results are shown in Table 2.
[0045]
In Example 1, the total light transmittance of the test piece is 59%, and the spectral light transmittance at 450 to 650 nm is 59 to 68%, which is a preferable result. Furthermore, the spectral light transmittance at 800 nm is 2%, which is very preferable, and when it is installed on the front surface of the plasma display, it is very preferable because an improvement in image contrast and a sense of unity with the housing are recognized. Further, the deflection temperature under load is preferably 140 ° C.
[0046]
In Example 2, the total light transmittance of the test piece is 72%, and the spectral light transmittance at 450 to 650 nm is 73 to 78%, which is a preferable result. Further, the spectral light transmittance at 800 nm is 7%, which is very preferable. Further, the material installed on the front surface of the plasma display is preferable since it has an effect of image contrast and a sense of unity with the housing.
[0047]
(Example 3)
Test pieces were prepared under the same conditions as in Example 1 except that three kinds of compounds each having an absorbance of 0.03 or more were used at the blending concentrations shown in Table 1, and evaluations (2) to (5) were made. I do. The evaluation results are shown in Table 2.
Thus, a spectral light transmittance of 450 to 650 nm is 60 to 69%, and a preferable result is obtained. The spectral light transmittance at 800 nm does not show 20% or less. However, when it is installed on the front surface of the plasma display, an improvement in image contrast and a sense of unity with the housing are recognized.
[0048]
(Comparative Examples 1-4)
A test piece is prepared under the same conditions as in Example 1 except that the type and compounding concentration of the compound are changed according to Table 1, and the evaluations (2) to (5) are performed. The absorbance of each of the compounds used is as shown in Table 1. The evaluation results are shown in Table 2.
In Comparative Examples 1 and 2, the spectral light transmittance of 450 to 650 nm of the test piece exceeds 85%, which is not preferable. In addition, it is not preferable that it is installed on the front surface of the plasma display in that no improvement in the contrast of the image is observed.
[0049]
In Comparative Example 3, the total light transmittance of the test piece shows 75%, but the spectral light transmittance is almost 0% in the range of 450 to 500 nm, which is not preferable. Moreover, when it is installed on the front surface of the plasma display, it is not preferable because it can be determined that there is no effect because the screen appears to be raised especially after the power is turned off.
In Comparative Example 4, the total light transmittance of the test piece shows 52%, but the spectral light transmittance of 450 to 650 nm shows 36%, which is not preferable. Moreover, since it shows opacity, it cannot be used as a front material of a plasma display.
[0050]
(Comparative Example 5)
The same procedure as in Example 1 was carried out except that the resin used was changed from a polycarbonate resin to a methacrylic resin (trade name: Delpowder 70H, manufactured by Asahi Kasei Kogyo Co., Ltd.) that is often used at present. As optical characteristics, the total light transmittance of the test piece is 63%, the spectral light transmittance at 450 to 650 nm is 62 to 71%, and a preferable result is obtained, and further, the spectral light transmittance at 800 nm is also 2%. Very preferred. Further, when it is installed on the front surface of the plasma display, an improvement in image contrast and a sense of unity with the housing part are recognized, which is very preferable, but the heat resistance is not as low as 40 ° C. compared to Example 1, and is not preferable.
[0051]
[Table 1]

[0052]
[Table 2]

[0053]
【The invention's effect】
The resin composition and the molded body obtained by the present invention are small in light amount loss due to light scattering and diffusion, effectively transmit light in a wavelength band of 450 to 650 nm, have high image contrast, and are housing when the device is turned off. There is a sense of unity between the image display unit and the image display unit, and the heat resistance is improved as compared with the conventional product.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing the configuration of a resin molded body obtained by the present invention and two types of plasma displays.
FIG. 2 is a diagram schematically showing the principle of measuring the absorbance of a compound used in the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Plasma 11 Ultraviolet ray 12 Visible light 2 Glass substrate 21 Display electrode 22 Address electrode 23 Cathode electrode 24 Anode electrode 25 Partition 31 Dielectric 32 Protective layer 33 Resistance 34 Insulator 4 Phosphor 5 Molding material 6 Light source 61 Light incident on the sample 7 Sample to be measured 71 Light emitted from the sample

Claims (5)

A polycarbonate resin composition comprising a polycarbonate resin and at least one light-absorbing compound having an absorbance of 0.01 or more in a wavelength region of 250 to 3000 nm, the total amount when the composition is molded into a sheet-like material A polycarbonate resin composition for video equipment having a light transmittance of 50 to 90% and a spectral light transmittance in a visible light wavelength region of 450 to 650 nm of 50 to 85% . A polycarbonate resin composition comprising a polycarbonate resin and at least one light-absorbing compound having an absorbance of 0.01 or more in a wavelength region of 250 to 3000 nm, the total amount when the composition is molded into a sheet-like material A polycarbonate resin composition for video equipment , having a light transmittance of 50 to 90% and a spectral light transmittance of 20% or less at a wavelength of 800 nm. A polycarbonate resin composition comprising a polycarbonate resin and at least one light-absorbing compound having an absorbance of 0.01 or more in a wavelength region of 250 to 3000 nm, the total amount when the composition is molded into a sheet-like material The light transmittance is 50 to 90%, the spectral light transmittance in the visible light wavelength region of 450 to 650 nm is in the range of 50 to 85%, and the spectral light transmittance at a wavelength of 800 nm is 20% or less. A polycarbonate resin composition for video equipment . A molded article obtained by molding the polycarbonate resin composition according to any one of claims 1 to 3 into an arbitrary shape. Molded body according to claim 4 comprising feature is characterized in that it is a molded body for a plasma display which is installed in front of the image display unit.

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