JP3590194B2 - Additive-containing thermoplastic resin molded article and method for producing the same - Google Patents

Description

【０００８】
本発明の成形体を構成する熱可塑性樹脂は、そのポリマー分子の側鎖にエステル基又はカルボキシル基を有するため、この熱可塑性樹脂を加熱溶融して所定の形状に成形する前に、アミノ基、水酸基、カルボキシル基、エステル基のいずれかの官能基を有する添加剤を、加熱溶融状態の熱可塑性樹脂に配合すると、添加剤とポリマー分子の側鎖がエステル交換反応を起こし、添加剤がポリマー分子の側鎖にエステル結合して固定化される。このように添加剤が固定化された熱可塑性樹脂で成形した本発明の成形体は、添加剤が経時的に揮散、消失することがないので、長期間に亘って添加剤の効能を維持することができる。
【０００９】
また、添加剤をポリマー分子の側鎖にエステル結合させると、添加剤が分子レベルで細かく分散した状態となるため、添加剤の分散粒子と熱可塑性樹脂の光屈折率が異なっていても、透過光の屈折、散乱が減少する。従って、添加剤による成形体の透明性の低下は極く僅かであり、従来の成形体のように物理的に分散させた添加剤が二次凝集して熱可塑性樹脂本来の透明性を大幅に損なう欠点を解消することができる。この効果は、アクリル系樹脂に添加剤をエステル結合させた場合に顕著に発揮される。
【００１０】
更に、熱可塑性樹脂のポリマー分子が、その側鎖にエステル結合した二官能の添加剤によって三次元架橋されているので、この架橋によって成形体の物性、殊に耐熱性が顕著に向上し、後述の実験データに示すように、熱可塑性単独の成形体に比べて、ガラス転移点（Ｔｇ）が２０℃程度上昇する。
【００１１】
そして、添加剤として、アミノ基、水酸基、カルボキシル基、エステル基のいずれかの官能基を有するポリジメチルシロキサンが添加剤しとて含有され、このポリジメチルシロキサンンが溌水性を有するシリコン系化合物であるため、長期に亘って良好な耐汚染性を保持することができる。
【００１２】
【発明の実施の形態】
以下、図面を参照して本発明の具体的な実施形態を詳述する。
【００１３】
図１は本発明の製造方法の一実施形態を示す概略説明図で、添加剤を含有したアクリル系樹脂の板状成形体（添加剤含有アクリル系樹脂板）を連続押出成形する場合を例示したものである。
【００１４】
図１において、１は溶融押出成形機、１ａは成形機の後部に設けた樹脂投入用ホッパー、１ｂは成形機の中間部に設けた添加剤投入用ホッパー、１ｃは成形機に内装したスクリュー、１ｄは成形機の先端に設けた成形用の金型、１ｅは成形の中間部に設けた二酸化炭素吹込み口、２は上下一対の冷却ロール、３は搬送ベルト、４は切断機である。
【００１５】
この実施形態では、予備加熱で乾燥させた原料のアクリル系樹脂５を成形機後部のホッパー１ａから成形機１の内部へ投入し、アクリル系樹脂５を溶融温度以上（但し分解温度以下）に加熱して溶融させながらスクリュー１ｃで混練する。そして、アミノ基、水酸基、カルボキシル基、エステル基のいずれかの官能基を有する添加剤６を成形機中間部のホッパー１ｂから投入し、二酸化炭素吹込み口１ｅより二酸化炭素を吹込みながら、加熱溶融状態のアクリル系樹脂５と添加剤６をスクリュー１ｃで均一に混練してエステル交換反応させた後、先端の金型１ｄから板状に押出成形して、この板状成形体５０を上下一対の冷却ロール２，２で冷却しながら引取り、搬送用ベルト３で切断機４へ搬送して所定の長さに切断する。
【００１６】
原料のアクリル系樹脂５は、そのポリマー分子が前記の［化２］の構造式で示されるものであって、具体的には、側鎖にカルボキシル基を有するポリアクリル酸もしくはポリメタクリル酸や、側鎖にメチルエステル基、エチルエステル基、プロピルエステル基のいずれかを有するポリアクリル酸アルキルエステルもしくはポリメタクリル酸アルキルエステルが使用される。
【００１７】
このようなアクリル系樹脂５は、側鎖のカルボキシル基やエステル基が官能性を有するため、上記のように成形機１の内部で溶融温度以上、分解温度以下の温度に加熱して溶融状態とし、アミノ基、水酸基、カルボキシル基、エステル基のいずれかの官能基を有する添加剤６と混練すると、ポリマ−分子の側鎖と添加剤がエステル交換反応し、添加剤がポリマ−分子の側鎖にエステル結合して固定化される。その場合、塩化鉄、酢酸コバルト、トリメチルアミンなどのエステル交換用触媒を、アクリル系樹脂１００重量部に対し０．００１〜０．５重量部程度の割合で配合すると、エステル交換反応が促進される。
【００１８】
特に、本実施形態のように二酸化炭素を成形機１の内部へ吹込んでエステル交換反応を二酸化炭素雰囲気下で行う場合は、二酸化炭素の可塑化効果と溶媒効果によってエステル交換反応が著しく促進され、その反応率が大幅に向上する。前者の可塑化効果は、二酸化炭素が熱可塑性樹脂の可塑剤的な作用をして樹脂の溶融粘度を減少させるため、ポリマー分子の側鎖のエステル基又はカルボキシル基と添加剤の官能基の接触する機会が多くなってエステル交換反応が促進されると考えられるものであり、後者の溶媒効果は、ポリマー分子側鎖のエステル基又はカルボキシル基の−ＣＯＯ−と二酸化炭素が同一の元素構成であるため、炭酸ガスがエステル基又はカルボキシル基の周囲に集まって溶媒的な作用をし、エステル基又はカルボキシル基が反応しやすい状態になってエステル交換反応が促進されると考えられるものである。
【００１９】
上記の実施形態では、原料樹脂としてアクリル系樹脂を用いているが、側鎖にエステル基又はカルボキシル基を有する熱可塑性樹脂であれば、アクリル系以外の樹脂を用いてもよく、例えばマレイン化したポリエチレンやマレイン化したポリスチレンを用いても同様に添加剤がエステル結合して固定化される。
【００２０】
前記のように添加剤が固定化されたアクリル系樹脂を押出成形して得られる成形体５０は、添加剤が経時的に揮散、消失することがないので、長期間に亘って添加剤の効能を維持することができる。しかも、添加剤はエステル結合により分子レベルで細かく分散しており、物理的に分散させた場合のように添加剤の粒子が二次凝集することもないので、添加剤の分散粒子とアクリル系樹脂の光屈折率が異なっていても、透過光の屈折、散乱により成形体５０の透明性が低下することは殆どなく、成形体５０はアクリル系樹脂単独の成形体とあまり変わらない良好な透明性を保持できる。
【００２１】
添加剤６は、分子末端又は分子中にアミノ基、水酸基、カルボキシル基、エステル基のいずれかの官能基を有し、アクリル系樹脂のポリマー分子の側鎖とエステル交換反応し得るものであれば全て使用可能であり、目的とするアクリル系樹脂成形体に要求される効能を付与できるものを種々選択して使用すればよい。そして、添加剤６の含有量についても、その効能が充分発揮されるように適宜決定すればよい。
【００２２】
例えば、アクリル系樹脂成形体に耐汚染性が要求される場合は、添加剤６として、下記の［化３］の構造式で示される分子両末端にアミノ基を有するポリジメチルシロキサン、下記の［化４］の構造式で示される分子中にアミノ基を有するポリジメチルシロキサン、下記の［化５］の構造式で示される分子片末端にカルボキシル基を有するポリジメチルシロキサン、下記の［化６］の構造式で示される分子両末端に水酸基を有するポリジメチルシロキサン、下記の［化７］の構造式で示される分子両端にエステル基を有するポリジメチルシロキサンなどのシリコン系化合物が防汚剤として好適に使用でき、また、分子両端に水酸基を有しているフッ素化ビスフェノールＡ［２，２−ビス−（４−ヒドロキシフェニル）−ヘキサフルオロプロパン］などのフッ素系化合物も防汚剤しとて好適に使用できる。
【化３】

【化４】

【化５】

【化６】

【化７】

【００２３】
これらのシリコン系又はフッ素系の防汚剤は、アクリル系樹脂１００重量部に対し０．１〜５重量部の割合で配合してポリマー分子の側鎖にエステル結合させると、アクリル樹脂成形体に良好な溌水性を付与して優れた耐汚染性を長期間保持させることができる。尚、場合によっては、官能基をもたない下記の［化８］の構造式で示されるポリジメチルシロキサンや、フルオロカーボン等を上記の防汚剤と併用してもよい。
【化８】

【００２４】
また、アクリル系樹脂成形体に耐候性が要求される場合は、添加剤６として、分子末端にカルボキシル基を有する２−（２′−ヒドロキシ−５′−カルボキシフェニル）ベンゾトリアゾール、２−ヒドロキシベンゾフェノン−４−オキシ酢酸、或は、分子末端に２つ以上の水酸基を有する２−ヒドロキシ−４−（２′−ヒドロキシエトキシ）ベンゾフェノン、２，２′，４，４′，６，６′−ヘキサヒドロキシベンゾフェノン、２−（２′，４′−ジヒドロキシフェニル）ベンゾトリアゾール、２−ヒドロキシ−４−（２′−ヒドロキシエトキシ）ベンゾトリアゾール、２−ヒドロキシ−５−（２′−ヒドロキシエチル）ベンゾトリアゾール、或は、分子末端にアミノ基を有する２−（２′−ヒドロキシ−３′−アミノ−５′−ｔ−ブチル）ベンゾトリアゾール、或は、分子中にエステル基を有する２−ヒドロキシ−４−（２′−メタクリロイルオキシエトキシ）ベンゾフェノン、２，４−ジ−ｔ−ブチルフェニル−（３′，５′−ジ−ｔ−ブチル−４′−ヒドロキシ）ベンゾフェノン、２−ヒドロキシベンゾフェノン−４−オキシ酢酸メチル、２−（２′−アクリロイルオキシ−５′−メチル）ベンゾトリアゾールなどの、２−ヒドロキシベンゾトリアゾール誘導体又は２−ヒドロキシフェニルベンゾフェノン誘導体の紫外線吸収剤が好適に使用される。
【００２５】
これらの紫外線吸収剤は、アクリル系樹脂１００重量部に対し０．０１〜５重量部の割合で配合してポリマー分子の側鎖にエステル結合させると、紫外線による成形体の劣化を抑制して優れた耐候性を長期間保持させることができる。
【００２６】
その他、アクリル系樹脂成形体に要求される効能に応じて、テトラブロモビスフェノール等の難燃剤、チオジフェノール等の耐放射線剤、Ｎ，Ｎ−ジフェニル−ｐ−フェニレンジアミン等の抗酸化剤、トリブチル錫ラウレート等の抗菌剤、テトラフェニルジプロピレングリコールジホスファイト等の帯電防止剤、ジオクチルフタレートやドデカノール等の可塑剤など、各種添加剤が使用可能である。
【００２７】
以上の添加剤のうち、分子両端に官能基を有する二官能の添加剤を用いると、アクリル系樹脂のポリマー分子が、その側鎖にエステル結合した二官能の添加剤によって三次元架橋された構造となるため、アクリル系樹脂成形体５０の物性、殊に耐熱性が顕著に向上する。例えば、アクリル系樹脂５としてポリメタクリル酸メチル（ＰＭＭＡ：ポリメチルメタクリレート）を使用し、添加剤６として分子両端にアミノ基を有する前記［化３］のポリジメチルシロキサン（ＰＤＭＳ）を使用して、成形機の内部で両者をエステル交換反応させると、下記の［化９］に示すように、隣接するＰＭＭＡのポリマー分子の側鎖にＰＤＭＳの分子両端がそれぞれエステル結合して架橋するため、このようにエステル結合した多くのＰＤＭＳによって各ポリマー分子が三次元架橋された構造となり、後述の実施例のデータに示すように、得られる成形体のガラス転移点がＰＭＭＡ単独の非架橋の成形体よりも２０℃程度上昇して、耐熱性が大幅に向上する。但し、配合された二官能のＰＤＭＳはその全てが三次元架橋に寄与するわけではなく、一部のＰＤＭＳは分子一端のみがポリマー分子の側鎖にエステル結合して非架橋の状態となり、また未反応のＰＤＭＳはフリーの状態で成形体中に含まれることになる。
【化９】

【００２８】
エステル交換の反応速度は、アクリル系樹脂の種類や添加剤の種類によって多少異なるが、通常１〜１５分程度で反応がほぼ終了する。従って、この実施形態のように成形機１の内部でエステル交換反応を行わせて押出成形する場合は、添加剤６を成形機１に投入してアクリル系樹脂５と１〜１５分程度混練したのち金型１ｄから押出されるように、添加剤投入用ホッパー１ｂの位置やスクリュー設計、その他の押出条件を設定して、エステル交換反応を充分に行わせることが重要である。成形機１としては、２本のスクリュー１ｃによって均一な混練を行える二軸押出成形機が好適に使用される。
【００２９】
この実施形態では、アクリル系樹脂５と添加剤６をホッパー１ａ，１ｂから個別に成形機１に投入しているが、例えばホッパー１ａから両者を一緒に投入してもよいし、ホッパー１ｂから両者を混合したものを適量ずつ投入してもよく、このように投入方法は適宜選択することができる。また、この実施形態では、添加剤をエステル結合させた溶融アクリル系樹脂を金型１ｄから単層で押出して板状の成形体５０を製造しているが、金型１ｄ等を変更してシート、フィルム、異形品など、種々の形状の成形体を製造できることは勿論であり、更に、共押出成形機等を用いて、添加剤をエステル結合させた溶融アクリル系樹脂を上層とし、該上層より添加剤が少ないか又は全く含まない溶融アクリル系樹脂或は他の樹脂を上下二層もしくは三層に共押出成形して、添加剤を含むアクリル系樹脂層を表面に積層した二層ないし三層構造の板状成形体を製造することも勿論可能である。また、射出成形の場合でも、溶融アクリル系樹脂を射出成形機の金型内部へ射出する前に添加剤を混合してエステル交換反応させれば、同様に添加剤の揮散がない透明性の良好な成形品を得ることができる。
【００３０】
【実施例】
次に、本発明の更に具体的な実施例と比較例を説明する。
【００３１】
［実施例１］
熱可塑性樹脂としてアクリル系樹脂であるポリメチルメタクリレート（ＰＭＭＡ）を１００重量部、添加剤として分子両端にアミノ基を有するポリジメチルシロキサン（Ｈ_２Ｎ−ＰＤＭＳ−ＮＨ_２）を２．００重量部、触媒として塩化鉄を０．００１重量部の割合で混合し、この混合物を二軸押出成形機に投入して２３２℃で５分間溶融混練を行い、エステル交換反応させた後、成形機の金型から板状に押出成形して成形体を得た。そして、この成形体を切削して溶剤（ジクロロメタン）に溶解した後、ジメチルエーテルで沈殿させて未反応のＨ_２Ｎ−ＰＤＭＳ−ＮＨ_２を除去し、この沈殿物を再度ジクロロメタンに溶解して、これをキャスティングすることにより、厚さ７０μｍの試験用フィルムを作製した。
【００３２】
この試験用フィルムについて、Ｈ_２Ｎ−ＰＤＭＳ−ＮＨ_２のエステル交換反応の反応率を以下の方法で求めたところ、後記の［表１］に示すように、エステル交換反応したＨ_２Ｎ−ＰＤＭＳ−ＮＨ_２の量は０．４２重量部であり、反応率は２１．０％であった。
【００３３】
（エステル交換反応の反応率の試験方法）
試験用フィルムを溶解した重クロロホルム溶液の ^１ＨＮＭＲスペクトルを測定し、Ｓｉ−ＣＨ_３のプロトンの強度からエステル交換反応したＨ_２Ｎ−ＰＤＭＳ−ＮＨ_＿２の量を計算し、下記の［数１］の式より反応率を求める。
【数１】

【００３４】
次に、この試験用フィルムについて、５５０ｎｍの光の透過率、ガラス転移温度（Ｔｇ）を測定したところ、後記の［表１］に示すように光透過率は８８％、ガラス転移温度は１０２℃であった。
【００３５】
更に、上記の試験用フィルムを室温で事務用インクのブルーブラックインクに浸漬し、２週間浸漬後の５５０ｎｍの光透過率を測定したところ、後記の［表１］に示すように光透過率は７０％であった。
【００３６】
［実施例２］
二軸押出成形機に二酸化炭素を吹込み、ＰＭＭＡとＨ_２Ｎ−ＰＤＭＳ−ＮＨ_２のエステル交換反応を二酸化炭素雰囲気中で行った以外は実施例１と同様にして、厚さ７０μｍの試験用フィルムを作製した。
【００３７】
この試験用フィルムについて、実施例１と同様にして、エステル交換反応したＨ_２Ｎ−ＰＤＭＳ−ＮＨ_２の量、反応率、光透過率、ガラス転移温度を測定し、更に実施例１と同様の耐汚染性試験を行った。その結果を後記の［表１］に示す。
【００３８】
［比較例１］
実施例１で使用したＰＭＭＡをジクロロメタンに溶解し、これをキャスティングすることにより、Ｈ_２Ｎ−ＰＤＭＳ−ＮＨ_２を含まない厚さ７０μｍのフィルムを作製した。
【００３９】
このフィルムについて、実施例１と同様に、光透過率、ガラス転移温度を測定し、更に実施例１と同様の耐汚染性試験を行った。その結果を後記の［表１］に示す。
【００４０】
［比較例２］
実施例１で使用したＰＭＭＡ１００重量部とＨ_２Ｎ−ＰＤＭＳ−ＮＨ_２０．４２重量部との混合物をジクロロメタンに溶解し、これをキャスティングすることにより、Ｈ_２Ｎ−ＰＤＭＳ−ＮＨ_２を物理的に分散させた厚さ７０μｍのフィルムを作製した。
【００４１】
このフィルムについて、実施例１と同様に、光透過率、ガラス転移温度を測定し、更に実施例１と同様の耐汚染性試験を行った。その結果を後記の［表１］に示す。
【００４２】
［比較例３］
実施例１で使用したＰＭＭＡ１００重量部とＨ_２Ｎ−ＰＤＭＳ−ＮＨ_２１．０４重量部との混合物をジクロロメタンに溶解し、これをキャスティングすることにより、Ｈ_２Ｎ−ＰＤＭＳ−ＮＨ_２を物理的に分散させた厚さ７０μｍのフィルムを作製した。
【００４３】
このフィルムについて、実施例１と同様に、光透過率、ガラス転移温度を測定し、更に実施例１と同様の耐汚染性試験を行った。その結果を下記の［表１］に示す。
【表１】

【００４４】
この表１から、Ｈ_２Ｎ−ＰＤＭＳ−ＮＨ_２を含まないＰＭＭＡ単独の比較例１のフィルムは、光透過率が９０％と高く、優れた透明性を有しているが、耐汚染性試験における２週間浸漬後の光透過率が５０％と大幅に低下し、耐汚染性に劣っていることが判る。また、ガラス転移温度も９０℃であり、耐熱性が充分とは言えないものである。
【００４５】
一方、実施例１のフィルムは、Ｈ_２Ｎ−ＰＤＭＳ−ＮＨ_２がＰＭＭＡの側鎖にエステル結合して分子レベルで細かく分散しているため、光透過率が８８％と高く、ＰＭＭＡ単独の比較例１のフィルムの光透過率（９０％）に比べて僅か２％低下しているだけであり、良好な透明性を有することが判る。そして、この実施例１のフィルムは、耐汚染性試験における２週間浸漬後の光透過率が７０％であり、インク汚染による光透過率の大幅な低下が見られず、良好な耐汚染性を有することが判る。また、この実施例１のフィルムは、エステル結合したＨ_２Ｎ−ＰＤＭＳ−ＮＨ_２によってポリマー分子が三次元架橋されているため、そのガラス転移温度が比較例１のＰＭＭＡ単独フィルムのガラス転移温度（９０℃）より高い１０２℃になっており、耐熱性が向上していることが判る。
【００４６】
これに対し、Ｈ_２Ｎ−ＰＤＭＳ−ＮＨ_２を物理的に分散させた比較例２のフィルムは、Ｈ_２Ｎ−ＰＤＭＳ−ＮＨ_２の含有量が実施例１のフィルムと同じ０．４２重量部であるにもかかわらず、光透過率が４５％と大幅に低下しており、透明性に劣ることが判る。これは、分散したＨ_２Ｎ−ＰＤＭＳ−ＮＨ_２の粒子が二次凝集することによって、透過光の屈折、散乱が大きくなるためである。また、このフィルムはガラス転移温度が９１℃で実施例１のフィルムより低く、耐熱性の向上が殆どみられないものであり、耐汚染性試験における２週間浸漬後の光透過率も２８％とかなり大幅に低下し、耐汚染性があまり良くないものであることが判る。
【００４７】
更に、実施例２のフィルムは、二酸化炭素雰囲気中でエステル交換反応させたものであるため、その反応率が５１．９％と顕著に向上して、実施例１のフィルムの反応率の約２．５倍になり、１．０４重量部のＨ_２Ｎ−ＰＤＭＳ−ＮＨ_２がエステル結合して含有されている。このように実施例２のフィルムは、Ｈ_２Ｎ−ＰＤＭＳ−ＮＨ_２の含有量が多いにもかかわらず、その光透過率が実施例１のフィルムの光透過率と殆ど変わらない８７％であり、良好な透明性を有している。これは、Ｈ_２Ｎ−ＰＤＭＳ−ＮＨ_２がエステル結合により分子レベルで細かく分散して固定化され、二次凝集することがないからである。そして、この実施例２のフィルムのように多量のＨ_２Ｎ−ＰＤＭＳ−ＮＨ_２がエステル結合したものは、架橋密度が高くなるため耐熱性が顕著に向上し、ガラス転移温度が１１０℃まで上昇している。しかも、多量のＨ_２Ｎ−ＰＤＭＳ−ＮＨ_２によってフィルムの溌水性が強くなるため、耐汚染性試験における２週間浸漬後の光透過率が８２％と殆ど低下せず、耐汚染性に優れていることが判る。
【００４８】
これに対し、実施例２のフィルムと同量のＨ_２Ｎ−ＰＤＭＳ−ＮＨ_２を物理的に分散させた比較例３のフィルムは、光透過率が３２％と極端に低下し、透明性が悪いことが判る。そして、このフィルムはガラス転移温度が９０℃で実施例１のフィルムより低く、耐熱性の向上がみられないものであり、耐汚染性試験における２週間浸漬後の光透過率も２０％とかなり低下し、Ｈ_２Ｎ−ＰＤＭＳ−ＮＨ_２の含有量が多い割りには耐汚染性があまり良くないものであることが判る。
【００４９】
［実施例３］
二軸押出成形機に二酸化炭素を吹込み、ＰＭＭＡとＨ_２Ｎ−ＰＤＭＳ−ＮＨ_２のエステル交換反応を二酸化炭素雰囲気中で行った以外は実施例１と同様にして成形体を得た。そして、この成形体を切削して溶剤（ジクロロメタン）に溶解し、これをキャスティングすることによって、１．０４重量部のＨ_２Ｎ−ＰＤＭＳ−ＮＨ_２がエステル結合し、０．９６重量部のＨ_２Ｎ−ＰＤＭＳ−ＮＨ_２が未反応のまま含有された厚さ１１０μｍの試験用フィルムを作製した。
【００５０】
そして、この試験用フィルムについて、加熱前の光透過率（５５０ｎｍ）、９０℃で３０分間加熱した後の光透過率、９０℃で１時間加熱した後の光透過率をそれぞれ測定した。その結果を後記の［表２］に示す。
【００５１】
［比較例４］
比較例１と同様にして、Ｈ_２Ｎ−ＰＤＭＳ−ＮＨ_２を含まないＰＭＭＡ単独の厚さ１１０μｍのフィルムを作製し、実施例３と同様に、加熱前、９０℃で３０分加熱後、９０℃で１時間加熱後の光透過率を測定した。その結果を後記の［表２］に示す。
【００５２】
［比較例５］
Ｈ_２Ｎ−ＰＤＭＳ−ＮＨ_２の配合量を２．００重量部に変更した以外は比較例２と同様にして、Ｈ_２Ｎ−ＰＤＭＳ−ＮＨ_２を物理的に分散させた厚さ１１０μｍのフィルムを作製し、実施例３と同様に、加熱前、９０℃で３０分加熱後、９０℃で１時間加熱後の光透過率を測定した。その結果を下記の［表２］に示す。
【表２】

【００５３】
この表２から、実施例３のフィルムは、Ｈ_２Ｎ−ＰＤＭＳ−ＮＨ_２を２．００重量部と多量に含有しているにもかかわらず、ＰＭＭＡ単独の比較例４のフィルムと殆ど変わらない８３．７％の光透過率を有しており、透明性が良好であることが判る。これは、２．００重量部のＨ_２Ｎ−ＰＤＭＳ−ＮＨ_２のうち、１．０４重量部のＨ_２Ｎ−ＰＤＭＳ−ＮＨ_２がエステル結合して分子レベルで細かく分散しているため、これに影響されて未反応のＨ_２Ｎ−ＰＤＭＳ−ＮＨ_２も同様に細かく分散したためと考えられる。これに対し、実施例３のフィルムと同量の２．００重量部のＨ_２Ｎ−ＰＤＭＳ−ＮＨ_２を物理的に分散させた比較例５のフィルムは、光透過率が３．８７％であり、透明性がほぼ失われてしまうことが判る。
【００５４】
また、実施例３のフィルムと比較例４のフィルムは、加熱前の光透過率がそれぞれ８３．７％と８５．０％であったものが、９０℃で３０分加熱した後にはそれぞれ７７．７％と８０．０％に低下したが、加熱前後の光透過率の低下の割合はほぼ同程度である。このことから、実施例３の光透過率の低下はアクリル樹脂自体の低下であり、Ｈ_２Ｎ−ＰＤＭＳ−ＮＨ_２の影響ではないことが判る。さらに、比較例５のフィルムは加熱前後の光透過率の低下の割合が大きく、物理的に分散させたＨ_２Ｎ−ＰＤＭＳ−ＮＨ_２では、これが大きく影響することがわかる。このことより、実施例３のＨ_２Ｎ−ＰＤＭＳ−ＮＨ_２の分散状態は、加熱によっても分子レベルで分散していて変わっていないことがわかる。
【００５５】
［実施例４］
添加剤を分子片末端に水酸基を有するポリジメチルシロキサン（ＨＯ−ＰＤＭＳ）に変更した以外は実施例２と同様にして、厚さ７０μｍの試験用フィルムを作製した。
【００５６】
このフィルムについて、実施例１と同様に、光透過率、ガラス転移温度を測定し、更に実施例１と同様の耐汚染性試験を行った。その結果を下記の［表３］に示す。
【表３】

【００５７】
この表３を見ると、ＨＯ−ＰＤＭＳは反応量が少なく、０．８０重量％しか反応していない。これは、ＨＯ−ＰＤＭＳが１官能であり、２官能のＨ_２Ｎ−ＰＤＭＳ−ＮＨ_２より反応する機会が少ないためであること、及び、−ＮＨ_２と−ＯＨとの反応性の差異によるものである。このことから、一官能の添加剤より二官能の添加剤が好ましいことがわかる。更に、ガラス転移温度も９０℃とＰＭＭＡとほぼ同じ温度であり、三次元架橋していないことがわかる。
【００５８】
【発明の効果】
以上の説明から明らかなように、本発明の添加剤含有熱可塑性樹脂成形体は、添加剤が分子レベルで細かく分散して熱可塑性樹脂のポリマー分子の側鎖にエステル結合して固定化されるため、熱可塑性樹脂本来の優れた性質と殆ど変わらない程度の良好な性質を有し、熱可塑性樹脂がアクリル系樹脂の場合には、その優れた透明性を実質的に低下させる心配がなく、しかも、エステル結合した添加剤は経時的に揮散することがないので、長期間に亘って添加剤の効能を保持することができ、特にポリマー分子がその側鎖にエステル結合した二官能の添加剤によって三次元架橋されている成形体は、耐熱性も向上するといった顕著な効果を奏する。
【図面の簡単な説明】
【図１】本発明の製造方法の一実施形態を示す概略説明図である。
【符号の説明】
１ 押出成形機
１ｅ 二酸化炭素吹込み口
５ アクリル系樹脂
６ 添加剤
５０ 添加剤含有アクリル系樹脂成形体[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a thermoplastic resin molded article containing various additives so as not to volatilize and disappear, and a method for producing the same.
[0002]
[Prior art]
Moldings such as exterior building materials molded with a thermoplastic resin often contain additives such as an ultraviolet absorber and an antifouling agent in order to improve weather resistance and stain resistance. Above all, exterior building materials made of acrylic resin have relatively good transparency and weather resistance, and are used for applications requiring various lighting properties, such as roofing materials, outer wall materials, skylights, and soundproofing boards. ing.
[0003]
[Problems to be solved by the invention]
However, conventional additive-containing thermoplastic resin molded articles are those obtained by physically mixing and dispersing additives, so that the additives volatilize and disappear over time, and weather resistance, stain resistance, etc. Cannot be maintained for a long time.
[0004]
Also, if the additives are physically mixed and dispersed, the excellent heat resistance and mechanical strength inherent to the thermoplastic resin may be reduced, and the transparency of the acrylic resin may be significantly impaired. Was.
[0005]
The present invention has been made in view of the above circumstances, and has as its main object to provide an additive-containing thermoplastic resin molded article that does not volatilize with time of an additive and hardly causes a decrease in transparency, and a method for producing the same. Aim. In a preferred embodiment, it is intended to further improve the heat resistance, stain resistance, weather resistance, and the like of the molded article, and to improve the reaction rate of the additive.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the additive-containing thermoplastic resin molded product according to claim 1 of the present invention has an ester group or a carboxyl group on a side chain of a polymer molecule. Acrylic represented by the following structural formula In the resin molding, As an additive, Has an amino, hydroxyl, carboxyl or ester functional group Bifunctional polydimethylsiloxane Is contained, Polydimethylsiloxane But Acrylic Transesterification with the side chains of the resin polymer molecule to form an ester bond By doing so, the polymer molecules are three-dimensionally crosslinked with the polydimethylsiloxane. It is characterized by having.
Embedded image

[0008]
Since the thermoplastic resin constituting the molded article of the present invention has an ester group or a carboxyl group in the side chain of the polymer molecule, this Before molding the thermoplastic resin into a predetermined shape by heat melting, an additive having an amino group, a hydroxyl group, a carboxyl group, or any functional group of an ester group is added to the thermoplastic resin in a heat-melted state. The additive and the side chain of the polymer molecule undergo a transesterification reaction, and the additive is ester-bonded to the side chain of the polymer molecule and immobilized. The molded article of the present invention molded from the thermoplastic resin to which the additives are immobilized as described above maintains the efficacy of the additives over a long period of time because the additives do not volatilize and disappear over time. be able to.
[0009]
Also, when the additive is ester-bonded to the side chain of the polymer molecule, the additive is finely dispersed at the molecular level, so that even if the dispersed particles of the additive and the thermoplastic resin have different photorefractive indices, they can be transmitted. Light refraction and scattering are reduced. Therefore, the decrease in the transparency of the molded article due to the additive is extremely slight, and the additive physically dispersed as in the conventional molded article undergoes secondary aggregation to greatly improve the original transparency of the thermoplastic resin. The disadvantages can be eliminated. This effect is remarkably exhibited when the additive is ester-bonded to the acrylic resin.
[0010]
Further , Thermoplastic polymer molecules are three-dimensionally crosslinked by bifunctional additives ester-bonded to their side chains Because Due to this crosslinking, the physical properties of the molded article, particularly the heat resistance, are remarkably improved, and the glass transition point (Tg) is increased by about 20 ° C. as compared with the molded article made of thermoplastic alone, as shown in the experimental data described later. .
[0011]
And, as an additive, polydimethylsiloxane having any functional group of amino group, hydroxyl group, carboxyl group, and ester group is used. It is included as an additive, Polydimethylsiloxane is a water-repellent silicon compound, so it can maintain good stain resistance for a long time. To .
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.
[0013]
FIG. 1 is a schematic explanatory view showing one embodiment of the production method of the present invention, and illustrates a case where a plate-shaped molded article of an acrylic resin containing an additive (additive-containing acrylic resin sheet) is continuously extruded. Things.
[0014]
In FIG. 1, 1 is a melt extrusion molding machine, 1a is a hopper for adding resin provided at a rear portion of the molding machine, 1b is a hopper for adding additives provided at an intermediate portion of the molding machine, 1c is a screw provided inside the molding machine, 1d is a molding die provided at the tip of the molding machine, 1e is a carbon dioxide blowing port provided at an intermediate portion of the molding, 2 is a pair of upper and lower cooling rolls, 3 is a conveyor belt, and 4 is a cutting machine.
[0015]
In this embodiment, the raw material acrylic resin 5 dried by preliminary heating is put into the inside of the molding machine 1 from the hopper 1a at the rear of the molding machine, and the acrylic resin 5 is heated above the melting temperature (but below the decomposition temperature). And kneading with the screw 1c while melting. Then, an additive 6 having any one of an amino group, a hydroxyl group, a carboxyl group, and an ester group is charged from a hopper 1b at an intermediate portion of the molding machine, and heated while blowing carbon dioxide from a carbon dioxide blowing port 1e. The molten acrylic resin 5 and the additive 6 are uniformly kneaded with a screw 1c and subjected to a transesterification reaction, and then extruded into a plate shape from a die 1d at the tip, and the plate-shaped formed body 50 is paired up and down. While being cooled by the cooling rolls 2 and 2, and transported to the cutter 4 by the transport belt 3 and cut into a predetermined length.
[0016]
The raw material acrylic resin 5 has a polymer molecule The above [Formula 2] Specifically, polyacrylic acid or polymethacrylic acid having a carboxyl group in a side chain, or a methyl ester group, an ethyl ester group, or a propyl ester group in a side chain. The polyacrylic acid alkyl ester or the polymethacrylic acid alkyl ester is used.
[0017]
Such an acrylic resin 5 has a functional property in a carboxyl group or an ester group in a side chain, and thus is heated to a temperature higher than a melting temperature and lower than a decomposition temperature in the molding machine 1 as described above to be in a molten state. When kneaded with an additive 6 having a functional group of any of amino group, hydroxyl group, carboxyl group and ester group, the side chain of the polymer molecule and the additive undergo a transesterification reaction, and the additive becomes a side chain of the polymer molecule. Is immobilized through an ester bond. In this case, when a transesterification catalyst such as iron chloride, cobalt acetate, or trimethylamine is blended at a ratio of about 0.001 to 0.5 parts by weight based on 100 parts by weight of the acrylic resin, the transesterification reaction is promoted.
[0018]
In particular, when the transesterification reaction is performed in a carbon dioxide atmosphere by blowing carbon dioxide into the molding machine 1 as in the present embodiment, the transesterification reaction is remarkably accelerated by the plasticizing effect and the solvent effect of carbon dioxide, The reaction rate is greatly improved. The former plasticization effect is because carbon dioxide acts as a plasticizer for the thermoplastic resin and reduces the melt viscosity of the resin, so that the ester group or carboxyl group on the side chain of the polymer molecule contacts the functional group of the additive. It is thought that the transesterification reaction is promoted by increasing the chance of the reaction, and the latter solvent effect is that the ester group or the carboxyl group of the polymer molecule -COO- and carbon dioxide are the same element constitution. Therefore, it is considered that the carbon dioxide gas gathers around the ester group or the carboxyl group and acts like a solvent, and the ester group or the carboxyl group is easily reacted, so that the transesterification reaction is promoted.
[0019]
In the above embodiment, an acrylic resin is used as a raw material resin, but any thermoplastic resin having an ester group or a carboxyl group in a side chain may be used instead of an acrylic resin. Even when polyethylene or maleated polystyrene is used, the additive is similarly immobilized through an ester bond.
[0020]
The molded article 50 obtained by extrusion-molding the acrylic resin to which the additive is immobilized as described above does not volatilize or disappear over time, so that the effect of the additive over a long period Can be maintained. In addition, the additives are finely dispersed at the molecular level by ester bonds, and the particles of the additives do not secondary aggregate as in the case of physically dispersing. , The transparency of the molded body 50 hardly decreases due to refraction and scattering of transmitted light, and the molded body 50 has good transparency which is not so different from that of the acrylic resin alone. Can be held.
[0021]
The additive 6 has any functional group such as an amino group, a hydroxyl group, a carboxyl group, or an ester group at the molecular terminal or in the molecule, and is capable of transesterification with the side chain of the polymer molecule of the acrylic resin. All of them can be used, and those which can impart desired effects to the intended acrylic resin molded article may be selected and used in various ways. Then, the content of the additive 6 may be appropriately determined so that the effect is sufficiently exhibited.
[0022]
For example, when the acrylic resin molded body is required to have stain resistance, the following additive 6 is used. [Formula 3] Polydimethylsiloxane having amino groups at both ends of the molecule represented by the structural formula of [Formula 4] Polydimethylsiloxane having an amino group in the molecule represented by the structural formula of the following, [Formula 5] Polydimethylsiloxane having a carboxyl group at one molecular end represented by the structural formula of the following, [Formula 6] Polydimethylsiloxane having hydroxyl groups at both ends of the molecule represented by the structural formula of the following, [Formula 7] Silicon compounds such as polydimethylsiloxane having an ester group at both ends of the molecule represented by the following structural formula can be suitably used as an antifouling agent, and a fluorinated bisphenol A [2,2 -Bis- (4-hydroxyphenyl) -hexafluoropropane] can also be suitably used as an antifouling agent.
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[0023]
When these silicone-based or fluorine-based antifouling agents are blended at a ratio of 0.1 to 5 parts by weight with respect to 100 parts by weight of the acrylic resin and are ester-bonded to a side chain of the polymer molecule, the acrylic resin molded article is formed. Good water repellency can be imparted and excellent stain resistance can be maintained for a long time. In some cases, there is no functional group below. [Formula 8] Polydimethylsiloxane represented by the structural formula or a fluorocarbon may be used in combination with the above antifouling agent.
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[0024]
When the acrylic resin molded article is required to have weather resistance, the additive 6 may be 2- (2'-hydroxy-5'-carboxyphenyl) benzotriazole or 2-hydroxybenzophenone having a carboxyl group at the molecular end. -4-oxyacetic acid, or 2-hydroxy-4- (2'-hydroxyethoxy) benzophenone having two or more hydroxyl groups at the molecular terminal, 2,2 ', 4,4', 6,6'-hexa Hydroxybenzophenone, 2- (2 ', 4'-dihydroxyphenyl) benzotriazole, 2-hydroxy-4- (2'-hydroxyethoxy) benzotriazole, 2-hydroxy-5- (2'-hydroxyethyl) benzotriazole, Or 2- (2'-hydroxy-3'-amino-5'-t-butyl) having an amino group at the molecular terminal Benzotriazole, or 2-hydroxy-4- (2'-methacryloyloxyethoxy) benzophenone having an ester group in the molecule, 2,4-di-t-butylphenyl- (3 ', 5'-di- 2-hydroxybenzotriazole derivatives such as t-butyl-4'-hydroxy) benzophenone, methyl 2-hydroxybenzophenone-4-oxyacetate and 2- (2'-acryloyloxy-5'-methyl) benzotriazole; An ultraviolet absorber of a hydroxyphenylbenzophenone derivative is preferably used.
[0025]
When these ultraviolet absorbers are blended at a ratio of 0.01 to 5 parts by weight with respect to 100 parts by weight of the acrylic resin and are ester-bonded to the side chains of the polymer molecules, the deterioration of the molded article due to ultraviolet rays is suppressed, so that it is excellent. Weather resistance for a long period of time.
[0026]
In addition, depending on the effect required for the acrylic resin molded article, a flame retardant such as tetrabromobisphenol, a radiation-resistant agent such as thiodiphenol, an antioxidant such as N, N-diphenyl-p-phenylenediamine, tributyl Various additives such as an antibacterial agent such as tin laurate, an antistatic agent such as tetraphenyldipropylene glycol diphosphite, and a plasticizer such as dioctyl phthalate and dodecanol can be used.
[0027]
When a bifunctional additive having a functional group at both ends of the molecule is used, the polymer molecule of the acrylic resin is three-dimensionally cross-linked by the bifunctional additive ester-bonded to the side chain. Therefore, the physical properties of the acrylic resin molded body 50, particularly the heat resistance, are remarkably improved. For example, polymethyl methacrylate (PMMA: polymethyl methacrylate) is used as the acrylic resin 5, and the additive 6 has amino groups at both ends of the molecule. [Formula 3] Using a polydimethylsiloxane (PDMS), a transesterification reaction between the two inside the molding machine gives the following: [Formula 9] As shown in the figure, since both ends of the PDMS molecule are cross-linked by ester bonding to the side chains of the adjacent PMMA polymer molecules, a structure in which each polymer molecule is three-dimensionally cross-linked by many PDMS thus ester-bonded. As shown in the data of Examples described later, the glass transition point of the obtained molded body is increased by about 20 ° C. as compared with the non-crosslinked molded body of PMMA alone, and the heat resistance is greatly improved. However, not all of the compounded bifunctional PDMS contributes to three-dimensional cross-linking. Some PDMSs are not cross-linked because only one end of the molecule is ester-bonded to the side chain of the polymer molecule. The PDMS of the reaction will be included in the compact in a free state.
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[0028]
The transesterification reaction rate varies somewhat depending on the type of acrylic resin and the type of additive, but generally the reaction is almost completed in about 1 to 15 minutes. Therefore, when extruding by performing a transesterification reaction inside the molding machine 1 as in this embodiment, the additive 6 was charged into the molding machine 1 and kneaded with the acrylic resin 5 for about 1 to 15 minutes. It is important that the position of the hopper 1b for adding additives, the screw design, and other extrusion conditions are set so that the transesterification reaction is sufficiently carried out so as to be extruded from the mold 1d. As the molding machine 1, a twin-screw extruder capable of performing uniform kneading with two screws 1c is suitably used.
[0029]
In this embodiment, the acrylic resin 5 and the additive 6 are separately supplied to the molding machine 1 from the hoppers 1a and 1b. However, for example, both may be supplied together from the hopper 1a, or both may be supplied from the hopper 1b. May be charged in appropriate amounts, and the charging method can be appropriately selected. Further, in this embodiment, the plate-like molded body 50 is manufactured by extruding the molten acrylic resin in which the additive is ester-bonded from the mold 1d in a single layer, but the mold 1d and the like are changed to form a sheet. Of course, it is possible to produce molded articles of various shapes, such as films and irregularly shaped articles, and further, using a co-extrusion molding machine or the like, a molten acrylic resin in which additives are ester-bonded is used as an upper layer, and from the upper layer, Two or three layers of co-extrusion molding of molten acrylic resin or other resin with little or no additives into upper and lower two or three layers and laminating acrylic resin layer containing additives on the surface Of course, it is also possible to manufacture a plate-shaped molded body having a structure. Also, in the case of injection molding, if the additive is mixed and transesterified before the molten acrylic resin is injected into the mold of the injection molding machine, similarly, the additive has good transparency without volatilization. A molded article can be obtained.
[0030]
【Example】
Next, more specific examples and comparative examples of the present invention will be described.
[0031]
[Example 1]
100 parts by weight of polymethyl methacrylate (PMMA) which is an acrylic resin as a thermoplastic resin, and polydimethylsiloxane (H ₂ N-PDMS-NH ₂ 2.00 parts by weight) and 0.001 part by weight of iron chloride as a catalyst, and this mixture is charged into a twin-screw extruder, melt-kneaded at 232 ° C. for 5 minutes, and subjected to a transesterification reaction. After that, a molded product was obtained by extrusion molding into a plate shape from a mold of a molding machine. Then, after cutting this molded body and dissolving it in a solvent (dichloromethane), it is precipitated with dimethyl ether to remove unreacted H. ₂ N-PDMS-NH ₂ Was removed, this precipitate was dissolved again in dichloromethane, and this was cast to prepare a test film having a thickness of 70 μm.
[0032]
About this test film, ₂ N-PDMS-NH ₂ The transesterification rate was determined by the following method. As shown in Table 1 below, the transesterified H ₂ N-PDMS-NH ₂ Was 0.42 parts by weight, and the conversion was 21.0%.
[0033]
(Testing method of transesterification reaction rate)
Of heavy chloroform solution dissolving test film ¹ H NMR spectrum was measured and Si-CH ₃ From the proton intensity of H ₂ N-PDMS-NH _{_} The amount of 2 is calculated, and the reaction rate is calculated from the following equation (Equation 1).
(Equation 1)

[0034]
Next, the transmittance of this test film at 550 nm and the glass transition temperature (Tg) were measured. As shown in Table 1 below, the light transmittance was 88% and the glass transition temperature was 102 ° C. Met.
[0035]
Further, the test film was immersed in the office black ink at room temperature, and the light transmittance at 550 nm after immersion for 2 weeks was measured. The light transmittance was as shown in Table 1 below. 70%.
[0036]
[Example 2]
Carbon dioxide is blown into the twin screw extruder, PMMA and H ₂ N-PDMS-NH ₂ A test film having a thickness of 70 μm was prepared in the same manner as in Example 1 except that the transesterification reaction was performed in a carbon dioxide atmosphere.
[0037]
This test film was subjected to transesterification H in the same manner as in Example 1. ₂ N-PDMS-NH ₂ , The reaction rate, the light transmittance, and the glass transition temperature were measured, and the same stain resistance test as in Example 1 was performed. The results are shown in Table 1 below.
[0038]
[Comparative Example 1]
The PMMA used in Example 1 was dissolved in dichloromethane and cast to obtain HMA. ₂ N-PDMS-NH ₂ A film having a thickness of 70 μm containing no was prepared.
[0039]
About this film, the light transmittance and the glass transition temperature were measured in the same manner as in Example 1, and the same stain resistance test as in Example 1 was performed. The results are shown in Table 1 below.
[0040]
[Comparative Example 2]
100 parts by weight of PMMA used in Example 1 and H ₂ N-PDMS-NH ₂ Dissolve the mixture in 0.42 parts by weight in dichloromethane and cast it to give H ₂ N-PDMS-NH ₂ Was physically dispersed to prepare a film having a thickness of 70 μm.
[0041]
About this film, the light transmittance and the glass transition temperature were measured in the same manner as in Example 1, and the same stain resistance test as in Example 1 was performed. The results are shown in Table 1 below.
[0042]
[Comparative Example 3]
100 parts by weight of PMMA used in Example 1 and H ₂ N-PDMS-NH ₂ The mixture with 1.04 parts by weight was dissolved in dichloromethane and this was cast to give H ₂ N-PDMS-NH ₂ Was physically dispersed to prepare a film having a thickness of 70 μm.
[0043]
About this film, the light transmittance and the glass transition temperature were measured in the same manner as in Example 1, and the same stain resistance test as in Example 1 was performed. The results are shown in [Table 1] below.
[Table 1]

[0044]
From Table 1, H ₂ N-PDMS-NH ₂ The film of Comparative Example 1 containing no PMMA alone had a high light transmittance of 90% and excellent transparency, but had a light transmittance of 50% after immersion for 2 weeks in a stain resistance test. It can be seen that the temperature is greatly reduced and the stain resistance is poor. Further, the glass transition temperature is 90 ° C., and the heat resistance is not sufficient.
[0045]
On the other hand, the film of Example 1 ₂ N-PDMS-NH ₂ Is ester-bonded to the side chain of PMMA and is finely dispersed at the molecular level, so that the light transmittance is as high as 88%, which is only 2 compared to the light transmittance (90%) of the film of Comparative Example 1 using PMMA alone. %, Which indicates that it has good transparency. The film of Example 1 had a light transmittance of 70% after two weeks of immersion in the stain resistance test, and did not show a significant decrease in light transmittance due to ink contamination. It turns out that it has. In addition, the film of Example 1 was made of an ester-bonded H ₂ N-PDMS-NH ₂ Since the polymer molecules are three-dimensionally crosslinked, the glass transition temperature is 102 ° C., which is higher than the glass transition temperature (90 ° C.) of the PMMA single film of Comparative Example 1, and the heat resistance is improved. I understand.
[0046]
In contrast, H ₂ N-PDMS-NH ₂ The film of Comparative Example 2 in which ₂ N-PDMS-NH ₂ Is 0.42 parts by weight, which is the same as that of the film of Example 1, the light transmittance is greatly reduced to 45%, which indicates that the transparency is poor. This is the distributed H ₂ N-PDMS-NH ₂ This is because the secondary aggregation of the particles makes refraction and scattering of transmitted light large. Further, this film had a glass transition temperature of 91 ° C., which was lower than that of the film of Example 1, and showed little improvement in heat resistance. The light transmittance after immersion for 2 weeks in the stain resistance test was 28%. It can be seen that the resistance is considerably reduced, and the stain resistance is not so good.
[0047]
Further, since the film of Example 2 was subjected to a transesterification reaction in a carbon dioxide atmosphere, the reaction rate was remarkably improved to 51.9%, and the reaction rate of the film of Example 1 was about 2%. 0.5 times and 1.04 parts by weight of H ₂ N-PDMS-NH ₂ Is contained in an ester bond. Thus, the film of Example 2 has H ₂ N-PDMS-NH ₂ Despite the high content of, the light transmittance of the film of Example 1 was 87%, which is almost the same as that of the film of Example 1, and the film has good transparency. This is H ₂ N-PDMS-NH ₂ Is finely dispersed and immobilized at the molecular level by an ester bond, so that secondary aggregation does not occur. And, as in the film of Example 2, a large amount of H ₂ N-PDMS-NH ₂ Those having an ester bond have a remarkably improved heat resistance due to a high crosslinking density, and have a glass transition temperature of 110 ° C. Moreover, a large amount of H ₂ N-PDMS-NH ₂ As a result, the water repellency of the film becomes stronger, so that the light transmittance after immersion for 2 weeks in the stain resistance test hardly decreases to 82%, indicating that the film is excellent in stain resistance.
[0048]
On the other hand, the same amount of H as the film of Example 2 was used. ₂ N-PDMS-NH ₂ The film of Comparative Example 3 in which is physically dispersed has an extremely low light transmittance of 32%, indicating that the transparency is poor. This film has a glass transition temperature of 90 ° C., which is lower than that of the film of Example 1, and shows no improvement in heat resistance, and the light transmittance after immersion for 2 weeks in the stain resistance test is considerably 20%. Drops, H ₂ N-PDMS-NH ₂ It is understood that the stain resistance is not so good in spite of the high content of.
[0049]
[Example 3]
Carbon dioxide is blown into the twin screw extruder, PMMA and H ₂ N-PDMS-NH ₂ A molded article was obtained in the same manner as in Example 1 except that the transesterification reaction was performed in a carbon dioxide atmosphere. Then, the molded body is cut and dissolved in a solvent (dichloromethane), and cast to obtain 1.04 parts by weight of H. ₂ N-PDMS-NH ₂ Form an ester bond, and 0.96 parts by weight of H ₂ N-PDMS-NH ₂ Was produced in an unreacted state to prepare a test film having a thickness of 110 μm.
[0050]
The light transmittance (550 nm) of the test film before heating, the light transmittance after heating at 90 ° C. for 30 minutes, and the light transmittance after heating at 90 ° C. for 1 hour were measured. The results are shown in Table 2 below.
[0051]
[Comparative Example 4]
As in Comparative Example 1, H ₂ N-PDMS-NH ₂ A 110 μm-thick film of PMMA alone containing no was prepared, and the light transmittance before heating, after heating at 90 ° C. for 30 minutes, and after heating at 90 ° C. for 1 hour were measured in the same manner as in Example 3. The results are shown in Table 2 below.
[0052]
[Comparative Example 5]
H ₂ N-PDMS-NH ₂ Was changed in the same manner as in Comparative Example 2 except that the blending amount of H was changed to 2.00 parts by weight. ₂ N-PDMS-NH ₂ Was physically dispersed to prepare a film having a thickness of 110 μm. As in Example 3, the light transmittance was measured before heating, after heating at 90 ° C. for 30 minutes, and after heating at 90 ° C. for 1 hour. The results are shown in Table 2 below.
[Table 2]

[0053]
From Table 2, it can be seen that the film of Example 3 has H ₂ N-PDMS-NH ₂ Has a light transmittance of 83.7%, which is almost the same as that of the film of Comparative Example 4 containing only PMMA, and has good transparency. You can see that. This is 2.00 parts by weight of H ₂ N-PDMS-NH ₂ Of which 1.04 parts by weight of H ₂ N-PDMS-NH ₂ Are finely dispersed at the molecular level due to the ester bond, and unreacted H ₂ N-PDMS-NH ₂ It is considered that the fine particles were similarly finely dispersed. On the other hand, the same amount of 2.00 parts by weight of H as the film of Example 3 was used. ₂ N-PDMS-NH ₂ Has a light transmittance of 3.87%, indicating that the transparency is almost lost.
[0054]
The films of Example 3 and Comparative Example 4 had light transmittances of 83.7% and 85.0% before heating, respectively, and after heating at 90 ° C. for 30 minutes, each had a light transmittance of 77.70%. Although they decreased to 7% and 80.0%, the rate of decrease in light transmittance before and after heating was almost the same. From this, the decrease in the light transmittance in Example 3 is due to the decrease in the acrylic resin itself, ₂ N-PDMS-NH ₂ You can see that it is not the effect of Further, in the film of Comparative Example 5, the rate of decrease in the light transmittance before and after heating was large, and the physically dispersed H ₂ N-PDMS-NH ₂ It can be seen that this has a great effect. From this, H of Example 3 ₂ N-PDMS-NH ₂ It can be seen that the dispersion state of was not changed because it was dispersed at the molecular level even by heating.
[0055]
[Example 4]
A test film having a thickness of 70 μm was prepared in the same manner as in Example 2 except that the additive was changed to polydimethylsiloxane having a hydroxyl group at one molecular terminal (HO-PDMS).
[0056]
About this film, the light transmittance and the glass transition temperature were measured in the same manner as in Example 1, and the same stain resistance test as in Example 1 was performed. The results are shown in Table 3 below.
[Table 3]

[0057]
Referring to Table 3, the amount of HO-PDMS reacted was small, and only 0.80% by weight was reacted. This is because HO-PDMS is monofunctional and bifunctional H ₂ N-PDMS-NH ₂ It is because there is less opportunity to react, and -NH ₂ And -OH. This indicates that bifunctional additives are preferable to monofunctional additives. Furthermore, the glass transition temperature is 90 ° C., which is almost the same as that of PMMA, and it can be seen that there is no three-dimensional crosslinking.
[0058]
【The invention's effect】
As is clear from the above description, the additive-containing thermoplastic resin molded article of the present invention is such that the additive is finely dispersed at the molecular level and immobilized by ester bonding to the side chains of the polymer molecules of the thermoplastic resin. Therefore, it has good properties that are almost the same as the original excellent properties of the thermoplastic resin, and when the thermoplastic resin is an acrylic resin, there is no fear that the excellent transparency is substantially reduced, Moreover, since the ester-bonded additive does not volatilize over time, the effect of the additive can be maintained for a long period of time. In particular, a bifunctional additive in which a polymer molecule is ester-bonded to its side chain. The molded article three-dimensionally crosslinked has a remarkable effect of improving heat resistance.
[Brief description of the drawings]
FIG. 1 is a schematic explanatory view showing one embodiment of a manufacturing method of the present invention.
[Explanation of symbols]
1 Extrusion molding machine
1e Carbon dioxide inlet
5 Acrylic resin
6 additives
50 Additive-containing acrylic resin molding

Claims (1)

In a molded article of an acrylic resin represented by the following structural formula having an ester group or a carboxyl group in a side chain of a polymer molecule, as an additive, an amino group, a hydroxyl group, a carboxyl group, or a functional group of any of an ester group is used. difunctional polydimethylsiloxane is contained in, by the polydimethylsiloxane is an ester bond by exchange reaction side chain with an ester polymer molecules of the acrylic resin, three-dimensional cross-linking the polymer molecules at the polydimethyl siloxanes having additive-containing thermoplastic resin molded body characterized by being.

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