JP4019849B2 - Vehicle window material - Google Patents

Description

【００１０】
（上記式中、Ｒ¹、Ｒ²は、同一または相異なる水素原子または炭素数１〜５のアルキル基を表す。）
［２］前記共重合体（Ａ）中の(i)グルタル酸無水物の含有量が５〜６０重量％であることを特徴とする［１］記載の車両用窓材、
［３］前記不飽和カルボン酸単位(iii)は、下記一般式（２）で表される構造を有する［１］または［２］記載の車両用窓材、および
【００１１】
【化５】

【００１２】
（ただし、Ｒ³は水素又は炭素数１〜５のアルキル基を表す）
［４］前記不飽和カルボン酸アルキルエステル単位(ii)は、下記一般式（３）で表される構造を有する［１］〜［３］いずれか記載の車両用窓材である。
【００１３】
【化６】

【００１４】
（ただし、Ｒ⁴は水素又は炭素数１〜５のアルキル基を表し、Ｒ⁵は炭素数１〜６の脂肪族若しくは脂環式炭化水素基又は１個以上炭素数以下の数の水酸基若しくはハロゲンで置換された炭素数１〜６の脂肪族若しくは脂環式炭化水素基を示す）
【００１５】
【発明の実施の形態】
以下、本発明の車両用窓材について具体的に説明する。
【００１６】
本発明の車両用窓材として使用される共重合体は、（ｉ）下記一般式（１）
【００１７】
【化７】

【００１８】
（上記式中、Ｒ¹、Ｒ²は、同一または相異なる水素原子または炭素数１〜５のアルキル基を表す。）
で表されるグルタル酸無水物単位、（ii）不飽和カルボン酸アルキルエステル系単量体からなる共重合体、若しくは上記(i)、(ii)の単位および（iii）不飽和カルボン酸単位からなる共重合体、または上記(i)、(ii)の単位若しくは上記(i)、(ii)、(iii)の単位および(iv)芳香環を含まないその他のビニル系単量体単位からなる共重合体であり、これらは一種または二種以上で用いることができる。
【００１９】
本発明に用いる上記共重合体の製造方法に特に制限はないが、基本的には以下に示す方法により製造することができる。すなわち、後の加熱工程により上記一般式（１）で表されるグルタル酸無水物単位(i)を与える不飽和カルボン酸単量体及び不飽和カルボン酸アルキルエステル単量体と、前記芳香環を含まないその他のビニル系単量体単位(iv)を含む場合には該単位を与えるビニル系単量体とを共重合させ、原重合体（ａ）とした後、かかる原重合体（ａ）を適当な触媒の存在下あるいは非存在下で加熱し（イ）脱アルコール及び／又は（ロ）脱水による分子内環化反応を行わせることにより製造することができる。この場合、典型的には、原重合体（ａ）を加熱することにより２単位の不飽和カルボン酸単位(iii)のカルボキシル基が脱水されて、あるいは、隣接する不飽和カルボン酸単位(iii)と不飽和カルボン酸アルキルエステル単位(ii)からアルコールの脱離により１単位の前記グルタル酸無水物単位が生成される。
【００２０】
この際に用いられる不飽和カルボン酸単量体としては特に制限はなく、他のビニル化合物と共重合させることが可能ないずれの不飽和カルボン酸単量体も使用可能である。好ましい不飽和カルボン酸単量体として、下記一般式（４）
【００２１】
【化８】

【００２２】
（ただし、Ｒ³は水素又は炭素数１〜５のアルキル基を表す）
で表される化合物、マレイン酸、及びさらには無水マレイン酸の加水分解物などが挙げられるが、特に熱安定性が優れる点でアクリル酸、メタクリル酸が好ましく、より好ましくはメタクリル酸である。これらはその１種または２種以上用いることができる。なお、上記一般式（４）で表される不飽和カルボン酸単量体は、共重合すると上記一般式（２）で表される構造の不飽和カルボン酸単位を与える。 また不飽和カルボン酸アルキルエステル系単量体としては特に制限はないが、好ましい例として、下記一般式（５）で表されるものを挙げることができる。
【００２３】
【化９】

【００２４】
（ただし、Ｒ⁴は水素又は炭素数１〜５のアルキル基を表し、Ｒ⁵は炭素数１〜６の脂肪族若しくは脂環式炭化水素基又は１個以上炭素数以下の数の水酸基若しくはハロゲンで置換された炭素数１〜６の脂肪族若しくは脂環式炭化水素基を示す）
これらのうち、炭素数１〜６の脂肪族若しくは脂環式炭化水素基又は置換基を有する該炭化水素基を持つアクリル酸エステルおよび／またはメタクリル酸エステルが特に好適である。なお、上記一般式（５）で表される不飽和カルボン酸アルキルエステル単量体は、共重合すると上記一般式（３）で表される構造の不飽和カルボン酸アルキルエステル単位を与える。
【００２５】
不飽和カルボン酸アルキルエステル単量体の好ましい具体例としては、（メタ）アクリル酸メチル、（メタ）アクリル酸エチル、（メタ）アクリル酸ｎ−プロピル、（メタ）アクリル酸ｎ−ブチル、（メタ）アクリル酸ｔ−ブチル、（メタ）アクリル酸ｎ−へキシル、（メタ）アクリル酸シクロヘキシル、（メタ）アクリル酸クロロメチル、（メタ）アクリル酸２−クロロエチル、（メタ）アクリル酸２−ヒドロキシエチル、（メタ）アクリル酸３−ヒドロキシプロピル、（メタ）アクリル酸２，３，４，５，６−ペンタヒドロキシヘキシルおよび（メタ）アクリル酸２，３，４，５−テトラヒドロキシペンチルなどが挙げられ、なかでもメタクリル酸メチルが最も好ましく用いられる。これらはその１種または２種以上を用いることができる。
【００２６】
また、本発明で用いる共重合体（Ａ）の製造においては、本発明の効果を損なわない範囲で、芳香環を含まないその他のビニル系単量体を用いてもかまわない。芳香環を含まないその他のビニル系単量体の好ましい具体例としては、アクリロニトリル、メタクリロニトリル、エタクリロニトリルなどのシアン化ビニル系単量体、アリルグリシジルエーテル、無水マレイン酸、無水イタコン酸、Ｎ−メチルマレイミド、Ｎ−エチルマレイミド、Ｎ−シクロヘキシルマレイミド、アクリルアミド、メタクリルアミド、Ｎ−メチルアクリルアミド、ブトキシメチルアクリルアミド、Ｎ−プロピルメタクリルアミド、アクリル酸アミノエチル、アクリル酸プロピルアミノエチル、メタクリル酸ジメチルアミノエチル、メタクリル酸エチルアミノプロピル、メタクリル酸シクロヘキシルアミノエチル、Ｎ−ビニルジエチルアミン、Ｎ−アセチルビニルアミン、アリルアミン、メタアリルアミン、Ｎ−メチルアリルアミン、２−イソプロペニル−オキサゾリン、２−ビニル−オキサゾリン、２−アクロイル−オキサゾリンおよびなどを挙げることができ、これらは単独ないし２種以上を用いることができる。
【００２７】
芳香環を含むビニル系単量体を共重合すると、耐擦傷性、耐油性、耐候性が低下する傾向にあるため、共重合しないことが好ましいが、本発明の効果を損なわない範囲であれば差し支えない。かかる芳香環を含むビニル系単量体としては、Ｎ−フェニルマレイミド、メタクリル酸フェニルアミノエチル等があげられる。なお、スチレン、α−メチルスチレン、ｐ−グリシジルスチレン、ｐ−アミノスチレン、２−スチリル−オキサゾリンなどの芳香族ビニル系単量体については、特に上記特性が低下する傾向が強いため、共重合しないことが好ましいが、共重合する場合には、１重量％未満にとどめる必要がある。
【００２８】
原重合体（ａ）の重合方法については、基本的にはラジカル重合による、塊状重合、溶液重合、懸濁重合、乳化重合等の公知の重合方法を用いることができるが、不純物がより少ない点で溶液重合、塊状重合、懸濁重合が特に好ましい。
【００２９】
また、原重合体（ａ）を９０℃以下の重合温度で製造することが、加熱処理後の無色透明性の面で好ましく、より好ましい重合温度は８０℃以下であり、特に好ましくは７０℃以下である。また、重合温度の下限は、重合が進行する温度であれば、特に制限はないが、重合速度を考慮した生産性の面から、通常５０℃以上、好ましくは６０℃以上である。また重合時間は、必要な重合率を得るのに十分な時間であれば特に制限はないが、生産効率の点から６０〜３６０分間の範囲が好ましく、９０〜１８０分間の範囲が特に好ましい。
【００３０】
本発明において、原重合体（ａ）の製造時に用いられるこれらの単量体混合物の好ましい割合は、該単量体混合物を１００重量％として、不飽和カルボン酸系単量体が１５〜５０重量％、より好ましくは２０〜４５重量％、不飽和カルボン酸アルキルエステル系単量体は好ましくは５０〜８５重量％、より好ましくは５５〜８０重量％、これらに共重合可能な芳香環を含まない他のビニル系単量体を用いる場合、その好ましい割合は０〜３５重量％である。
【００３１】
不飽和カルボン酸系単量体量が１５重量％未満の場合には、原重合体（ａ）の加熱による上記一般式（１）で表されるグルタル酸無水物単位の生成量が少なくなり、耐熱性向上効果が小さくなる傾向がある。一方、不飽和カルボン酸系単量体量が５０重量％を超える場合には、原重合体（ａ）の加熱による環化反応後に、不飽和カルボン酸単位が多量に残存する傾向があり、無色透明性、滞留安定性が低下する傾向がある。
【００３２】
本発明における原重合体（ａ）を加熱し、（イ）脱水および／または（ロ）脱アルコールにより分子内環化反応を行いグルタル酸無水物単位を含有する共重合体を製造する方法は、特に制限はないが、ベントを有する加熱した押出機に通して製造する方法や窒素気流中または真空下で加熱脱揮できる装置内で製造する方法が好ましい。なお、上記の方法により加熱脱揮する温度は、（イ）脱水および／または（ロ）脱アルコールにより分子内環化反応が生じる温度であれば特に限定されないが、好ましくは１８０〜３００℃の範囲、特に２００〜２８０℃の範囲が好ましい。また、この際の加熱脱揮する時間も特に限定されず、所望する共重合組成に応じて適宜設定可能であるが、通常、１分間〜６０分間の範囲が好ましい。
【００３３】
さらに本発明では、原重合体（ａ）を上記方法等により加熱する際にグルタル酸無水物への環化反応を促進させる触媒として、酸、アルカリ、塩化合物の１種以上を添加することができる。その添加量は特に制限はなく、原重合体（ａ）１００重量部に対し、０．０１〜１重量部程度が適当である。また、これら酸、アルカリ、塩化合物の種類についても特に制限はなく、酸触媒としては、塩酸、硫酸、ｐ−トルエンスルホン酸、リン酸、亜リン酸、フェニルホスホン酸、リン酸メチル等が挙げられる。塩基性触媒としては、金属水酸化物、アミン類、イミン類、アルカリ金属誘導体、アルコキシド類、水酸化アンモニウム塩等が挙げられる。さらに、塩系触媒としては、酢酸金属塩、ステアリン酸金属塩、炭酸金属塩等が挙げられる。これら触媒は本発明の目的を損なわない範囲で１種または２種以上添加することができる。
【００３４】
本発明に使用される共重合体中の前記一般式（１）で表されるグルタル酸無水物単位の含有量は、好ましくは共重合体中に５〜６０重量％、より好ましくは１０〜５０重量％である。グルタル酸無水物単位が５重量％未満である場合、耐熱性向上効果が小さく、また耐傷性（表面硬度）が低下する傾向がある。なお、該グルタル酸無水物単位の定量には、一般に赤外分光光度計が用いられる。グルタル酸無水物単位は、１８００ｃｍ^-1及び１７６０ｃｍ^-1の吸収が特徴的であり、不飽和カルボン酸単位や不飽和カルボン酸アルキルエステル単位から区別することができる。
【００３５】
また、本発明に使用される共重合体中に含有される不飽和カルボン酸単位量は０〜１０重量％、より好ましくは０〜５重量％である。さらに、不飽和カルボン酸単位を実質的に含まないことが、無色透明性の点において最も好ましい。不飽和カルボン酸単位が１０重量％を超える場合には、無色透明性、滞留安定性が低下する傾向がある。また不飽和カルボン酸アルキルエステル単位は好ましくは４０〜９５重量％、より好ましくは５０〜９０重量％、芳香環を含まないその他のビニル系単量体単位は好ましくは０〜３５重量％である。なお、本発明の共重合体中に含有される各成分の定量には、上記した赤外分光光度計による方法とともに、１Ｈ−ＮＭＲによる方法を使用することができる。例えば、グルタル酸無水物単位、メタクリル酸、メタクリル酸メチルからなる共重合体の場合、スペクトルの帰属を、０．５〜１．５ｐｐｍのピークがメタクリル酸、メタクリル酸メチルおよびグルタル酸無水物環化合物のα−メチル基の水素、１．６〜２．１ｐｐｍのピークはポリマー主鎖のメチレン基の水素、３．５ｐｐｍのピークはメタクリル酸メチルのカルボン酸エステル（−ＣＯＯＣＨ₃）の水素、１２．４ｐｐｍのピークはメタクリル酸のカルボン酸の水素と、スペクトルの積分比から共重合体組成を決定することができる。
【００３６】
また、このような共重合体の極限粘度に特に制限はないが、ウベローデ型粘度計でジメチルホルムアミド溶液、３０℃で測定した極限粘度が０．１〜０．７ｄｌ／ｇであることが好ましく、より好ましくは０．３〜０．６ｄｌ／ｇである。
【００３７】
また、本発明で用いられる共重合体は、より好ましい態様において１２０℃以上のガラス転移温度（Ｔｇ）が得られ、特に好ましい態様においては１４０℃以上が得られる。上限に特に制限はないが、１６０℃程度のものも得られ、好ましく用いることができる。本発明で用いる共重合体は上記の如く高いガラス転移温度を有するため、過酷な気象条件下で使用される車両用窓材として、耐熱性の面で好適に使用することができる。尚、ここでいうガラス転移温度とは、示差走査熱量計（Ｐｅｒｋｉｎ Ｅｌｍｅｒ社製ＤＳＣ−７型）を用いて測定したガラス転移温度（Ｔｇ）である。
【００３８】
また、本発明に使用される共重合体は、特異的に表面硬度（鉛筆硬度）が高く、透明樹脂中最高レベルの耐傷性を有することを見出した。この際、より好ましい態様、特にグルタル酸無水物単位の含有量が好ましい範囲の場合において鉛筆硬度として４Ｈ以上の表面硬度が得られ、特に好ましい態様においては５Ｈ以上の表面硬度が得られる。なお、鉛筆硬度は８０ｍｍ×８０ｍｍ×３ｍｍの角板成形品を用いＪＩＳ−Ｋ−５４０１に従い測定されるものである。
【００３９】
さらに、本発明の車両用窓材には、本発明の目的を損なわない範囲でヒンダードフェノール系、ベンゾトリアゾール系、ベンゾフェノン系、ベンゾエート系、およびシアノアクリレート系の紫外線吸収剤および酸化防止剤、高級脂肪酸や酸エステル系および酸アミド系、さらに高級アルコールなどの滑剤および可塑剤、モンタン酸およびその塩、そのエステル、そのハーフエステル、ステアリルアルコール、ステラアマイドおよびエチレンワックスなどの離型剤、亜リン酸塩、次亜リン酸塩などの着色防止剤、ハロゲン系難燃剤、リン系やシリコーン系の非ハロゲン系難燃剤、核剤、アミン系、スルホン酸系、ポリエーテル系などの帯電防止剤、顔料などの着色剤などの添加剤を任意に含有させてもよい。ただし、その添加剤保有の色が窓材に悪影響を及ぼさず、かつ透明性が低下しない範囲で添加する必要がある。
【００４０】
これら添加剤の混合方法としては、本発明に使用される共重合体（Ａ）中に、これら添加剤が十分に分散する方法であれば、特に制限はないが、例えば、ミキサー、ニーダー、ロール、ブラベンダー、押出機などで樹脂を溶融状態にして混練する方法、適当な溶剤に溶解して分散させて凝固法、キャスト法、または直接乾燥法により溶剤を除去する方法などがある。押出機を用いる場合、混練後は、通常ストランドカッターでペレット化して用いられる。
【００４１】
本発明の車両用窓材は、上記の共重合体（Ａ）を成形することにより、樹脂板または樹脂シートとして得られるものである。樹脂板を成形する方法としては、射出成形、プレス成形、押出成形などが挙げられる。成形時の樹脂の溶融温度は、本発明に使用される共重合体（Ａ）の種類にも依るが、通常１００〜４００℃、好ましくは２００〜３５０℃である。
【００４２】
また、樹脂シートの製造方法としては、Ｔ−ダイ法、キャスト法、ホットプレス法が挙げられる。Ｔ−ダイ法による製造法の場合、単軸あるいは二軸押出スクリューのついたエクストルーダ型溶融押出装置等が使用できる。樹脂シートを製造するための溶融混練温度は、本発明に使用される共重合体（Ａ）の種類にも依るが、好ましくは１５０〜３５０℃、より好ましくは２００〜３００℃である。また、溶融押出装置を使用し溶融混練する場合、着色抑制の観点から、ベントを使用し減圧下での溶融混練あるいは窒素気流下での溶融混練を行うことが好ましい。また、ホットプレス法により樹脂シートを製造する場合、本発明に使用する共重合体（Ａ）の種類にも依るが、好ましいプレス温度は１５０〜３５０℃、より好ましくは２００〜３００℃である。
【００４３】
また、樹脂板および樹脂シートの厚みは、使用する窓材の適合部に依って適宜決定されるが、通常１〜１００ｍｍの範囲である。
【００４４】
本発明の車両用窓材は、極めて高い表面硬度を有するため、その表面にハードコート処理を行った場合に、ハードコート効果を著しく向上させることができ、耐傷性の点において車両用窓材として好適である。
【００４５】
窓材のハードコート処理は、公知の方法に従い、アクリル樹脂系、メラミン樹脂系、ポリシロキサン樹脂系等からなるハードコート剤を使用することができる。また、ハードコート方法としては、公知の方法を用いることができ、例えばバーコート法、ディップコート法、フローコート法、スプレーコート法、スピンコート法、ローラーコート法等を挙げることができる。
【００４６】
かくして得られた車両用窓材は、透明性、耐熱性に優れ、とりわけ耐油性、耐傷性、耐候性に優れるため、自動車の後部サイドウィンドウ、リアウィンドウ、サンルーフの窓、自動二輪車の風防ガラス等に実用的に使用することができる。
【００４７】
【実施例】
以下、実施例により本発明の構成、効果をさらに具体的に説明する。もっとも、本発明は下記実施例に限定されるものではない。各実施例の記述に先立ち、実施例で採用した各種物性の測定方法を記載する。
【００４８】
（１）透明性
東洋精機（株）製直読ヘイズメーターを用いて、８０ｍｍ×８０ｍｍ×３ｍｍの角板成形品の２３℃での全光線透過率（％）、ヘイズ（曇度）（％）を測定し、透明性を評価した。
【００４９】
（２）耐熱性
示差走査熱量計（Ｐｅｒｋｉｎ Ｅｌｍｅｒ社製ＤＳＣ−７型）を用い、窒素雰囲気下、２０℃／ｍｉｎの昇温速度でガラス転移温度（Ｔｇ）を測定した。
【００５０】
（３）剛性
ＡＳＴＭ Ｄ７４０に従い、１２．７ｍｍ×１２７ｍｍ×３ｍｍ厚試験片について曲げ弾性率を測定した。
【００５１】
（４）表面硬度
８０ｍｍ×８０ｍｍ×３ｍｍの角板成形品の鉛筆硬度をＪＩＳ−Ｋ−５４０１に従い測定した。
【００５２】
（５）耐油性
８０ｍｍ×８０ｍｍ×３ｍｍの角板成形品をギアー油（（株）ジャパンエナジー製ＧＥＡＲ５）に浸し、４０℃で２４時間浸漬処理後の全光線透過率を上記（１）項記載の方法で測定し、処理前後での全光線透過率の保持率（処理後の全光線透過率（％）／処理後の全光線透過率（％）×１００）を算出し、耐油性の指標とした。
【００５３】
（６）耐候性
８０ｍｍ×８０ｍｍ×３ｍｍの角板成形品をＪＩＳ Ｄ０２０５に規定されたサンシャインウェザーメーターで１０００時間暴露処理後の全光線透過率を上記（１）項記載の方法で測定し、処理前後での全光線透過率の保持率（（処理後の全光線透過率（％）／処理後の全光線透過率（％））×１００）を算出し、耐候性の指標とした。
【００５４】
〔実施例１〕
容量が２０リットルで、バッフルおよびファウドラ型撹拌翼を備えたステンレス製オートクレーブに、メタクリル酸メチル／アクリルアミド共重合体系懸濁剤（以下の方法で調整した。メタクリル酸メチル２０重量部、アクリルアミド８０重量部、過硫酸カリウム０．３重量部、イオン交換水１５００重量部を反応器中に仕込み反応器中を窒素ガスで置換しながら７０℃に保つ。反応は単量体が完全に、重合体に転化するまで続け、アクリル酸メチルとアクリルアミド共重合体の水溶液として得る。得られた水溶液を懸濁剤として使用した）０．０５部をイオン交換水１６５部に溶解した溶液を供給し、４００ｒｐｍで撹拌し、系内を窒素ガスで置換した。次に、下記混合物質を反応系を撹拌しながら添加し、７０℃に昇温した。内温が７０℃に達した時点を重合開始として、１８０分間保ち、重合を終了した。以降、通常の方法に従い、反応系の冷却、ポリマーの分離、洗浄、乾燥を行い、ビーズ状の原重合体（ａ−１）を得た。この原重合体（ａ−１）の重合率は９８％であった。
メタクリル酸（ＭＡＡ） ２５重量部
メタクリル酸メチル（ＭＭＡ） ７５重量部
ｔ−ドデシルメルカプタン ０．６重量部
２，２’−アゾビスイソブチロニトリル ０．４重量部
このビーズ状原重合体（ａ−１）を、スクリュウ径３０ｍｍ、Ｌ／Ｄが２５のベント付き同方向回転２軸押出機（池貝鉄工製 ＰＣＭ−３０）のホッパー口より供給して、樹脂温度２５０℃、スクリュウ回転数１００ｒｐｍで溶融押出し、ペレット状のグルタル酸無水物単位を含有する共重合体（Ａ−１）を得た。得られた共重合体（Ａ−１）を赤外分光光度計を用いて分析した結果、１８００ｃｍ^-1及び１７６０ｃｍ^-1に吸収ピークが確認され、この共重合体（Ａ−１）中にグルタル酸無水物単位が形成していることを確認した。また、この共重合体を重ジメチルスルホキシドに溶解させ、室温（２３℃）にて¹Ｈ−ＮＭＲを測定し、共重合体組成を決定したところ、メタクリル酸メチル（ＭＭＡ）単位７５重量％、グルタル酸無水物単位２０重量％、メタクリル酸（ＭＡＡ）単位５重量％であった。また、この共重合体（Ａ−１）の極限粘度は０．４６ｄｌ／ｇであった。得られた共重合体について射出成形機（東芝機械社製、ＩＳ５５ＥＰＮ）に供し、シリンダー温度２５０℃、金型温度８０℃で、それぞれの試験片を成形し、評価した。各種物性測定結果を表１に示した。
【００５５】
次に、上記共重合体を射出成形機（日精樹脂工業製ＦＮ１０００-１２Ｈ）に供し、シリンダー温度２５０℃、金型温度８０℃で射出成形し、３００ｍｍ×３００ｍｍ×３ｍｍの窓状成形品を得た。この窓状成形品にアクリル硬化型ハードコート剤をディップコート法にて塗布し、ハードコート層を形成した。この窓状成形品は透明性、耐傷性、耐油性、耐候性に優れ、成形品の外観上の欠点は認められなかった。この結果から、本発明の窓状成形品は車両用窓材として有用であることがわかった。
【００５６】
[実施例２]
単量体仕込み組成を下記組成に変更した以外は実施例１と同様に重合を行い、ビーズ状の原重合体（ａ−２）を得た。この原重合体（ａ−２）の重合率は９８％であった。
メタクリル酸（ＭＡＡ） １０重量部
メタクリル酸メチル（ＭＭＡ） ９０重量部
ｔ−ドデシルメルカプタン ０．６重量部
２，２’−アゾビスイソブチロニトリル ０．４重量部
このビーズ状原重合体（ａ−２）を、スクリュウ径３０ｍｍ、Ｌ／Ｄが２５のベント付き同方向回転２軸押出機（池貝鉄工製 ＰＣＭ−３０）のホッパー口より供給して、樹脂温度２５０℃、スクリュウ回転数１００ｒｐｍで溶融押出し、ペレット状のグルタル酸無水物単位を含有する共重合体（Ａ−２）を得た。得られた共重合体（Ａ−２）を実施例１と同様の方法で共重合体組成を決定したところ、メタクリル酸メチル単位８９重量％、グルタル酸無水物単位１１重量％、メタクリル酸単位０重量％であった。また、この共重合体（Ａ−２）の極限粘度は０．４４ｄｌ／ｇであった。得られた共重合体について、実施例１と同様に試験片を作成、評価した各種物性測定結果を表１に示した。
【００５７】
上記共重合体を用いて、実施例１と同様に３００ｍｍ×３００ｍｍ×３ｍｍの窓状成形品を射出成形して得た。この窓状成形品にアクリル硬化型ハードコート剤をディップコート法にて塗布し、ハードコート層を形成した。この窓状成形品は透明性、耐傷性、耐油性、耐候性に優れ、成形品の外観上の欠点は認められなかった。この結果から、本発明の窓状成形品は車両用窓材として有用であることがわかった。
【００５８】
[比較例１]
単量体仕込み組成を下記組成に変更した以外は実施例１と同様に重合を行い、ビーズ状の原重合体（ａ−３）を得た。この原重合体（ａ−３）の重合率は９８％であった。
メタクリル酸（ＭＡＡ） ２５重量部
メタクリル酸メチル（ＭＭＡ） ６５重量部
スチレン（Ｓｔ） １０重量部
ｔ−ドデシルメルカプタン ０．６重量部
２，２’−アゾビスイソブチロニトリル ０．４重量部
このビーズ状原重合体（ａ−３）を、スクリュウ径３０ｍｍ、Ｌ／Ｄが２５のベント付き同方向回転２軸押出機（池貝鉄工製 ＰＣＭ−３０）のホッパー口より供給して、樹脂温度２５０℃、スクリュウ回転数１００ｒｐｍで溶融押出し、ペレット状のグルタル酸無水物単位を含有する共重合体（Ａ−３）を得た。得られた共重合体（Ａ−３）を実施例１と同様の方法で赤外分光光度計を用いてこの共重合体（Ａ−３）中にグルタル酸無水物単位が形成していることを確認した。また、この共重合体を重ジメチルスルホキシドに溶解させ、室温（２３℃）にて¹Ｈ−ＮＭＲを測定し、スペクトルの帰属を、０．５〜１．５ｐｐｍのピークがメタクリル酸、メタクリル酸メチルおよびグルタル酸無水物環化合物のα−メチル基の水素、１．６〜２．１ｐｐｍのピークはポリマー主鎖のメチレン基の水素、２．４ｐｐｍのピークはスチレンのα−水素、３．５ｐｐｍのピークはメタクリル酸メチルのカルボン酸エステル（−ＣＯＯＣＨ₃）の水素、７．２ｐｐｍのピークはスチレンのベンゼン環の水素、１２．４ｐｐｍのピークはメタクリル酸のカルボン酸の水素とし、スペクトルの積分比から共重合体組成を決定したところ、メタクリル酸メチル単位６０重量％、グルタル酸無水物単位２０重量％、メタクリル酸単位５重量％、スチレン単位１５重量％であった。また、この共重合体（Ａ−３）の極限粘度は０．４５ｄｌ／ｇであった。得られた共重合体について実施例１と同様に試験片を作成、評価した各種物性測定結果を表１に示した。
【００５９】
また、上記共重合体を用いて、実施例１と同様に３００ｍｍ×３００ｍｍ×３ｍｍの窓状成形品を射出成形して得た。この窓状成形品にアクリル硬化型ハードコート剤をディップコート法にて塗布し、ハードコート層を形成した。この窓状成形品は透明性に優れるものの、耐油性、耐候性に劣るものであった。
【００６０】
〔比較例２〕
ポリカーボネート（ＰＣ）である三菱エンジニアリングプラスチック社製 “ユーピロン”Ｓ３０００を使用し実施例１と同様に試験片を作成、評価した各種物性測定結果を表１に示した。
【００６１】
また、上記共重合体を用いて、実施例１と同様に３００ｍｍ×３００ｍｍ×３ｍｍの窓状成形品を射出成形して得た。この窓状成形品にアクリル硬化型ハードコート剤をディップコート法にて塗布し、ハードコート層を形成した。この窓状成形品は耐油性、耐候性に劣り、車両用窓材としての性能は不十分であることがわかった。
【００６２】
〔比較例３〕
ポリメタクリル酸メチル（ＰＭＭＡ）である住友化学社製 “スミペックス”ＬＧを使用し、実施例１と同様に試験片を作成、評価した各種物性測定結果を表１に示した。
【００６３】
上記共重合体を用いて、実施例１と同様に３００ｍｍ×３００ｍｍ×３ｍｍの窓状成形品を射出成形して得た。この窓状成形品にアクリル硬化型ハードコート剤をディップコート法にて塗布し、ハードコート層を形成した。この窓状成形品は耐油性に劣るものであった。
【００６４】
【表１】

【００６５】
実施例１〜２、比較例１〜３の比較により、本発明の車両用窓材に使用される特定の共重合体は、従来材料であるＰＣやＰＭＭＡに対して、良好な透明性、耐熱性、機械特性を有し、とりわけ耐傷性、耐油性、耐候性に優れることがわかる。
【００６６】
一方、比較例１に示した共重合体は、良好な透明性、耐熱性を有するものの、耐油性、耐候性に劣り十分な車両用窓材としての性能を発現しないことがわかる。
【００６７】
【発明の効果】
以上述べたように、本発明によれば、透明性、耐熱性に優れ、とりわけ耐油性、耐傷性、耐候性に優れる車両用窓材を提供することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle window material having excellent transparency, heat resistance, surface hardness, weather resistance, and oil resistance, comprising a copolymer having a glutaric anhydride unit.
[0002]
[Prior art]
A glass plate is disposed in a window opening of a vehicle such as an automobile to form a window material. In recent years, in order to reduce the weight of vehicles such as automobiles, it has been proposed to use a transparent resin plate instead of a glass plate as a window material. However, since vehicles are used in harsh outdoor conditions, they require a high degree of durability against various external factors such as small changes in shape under high temperature and high humidity, scratch resistance, weather resistance, and oil resistance. The
[0003]
Examples of transparent resins used in vehicle window materials that satisfy these required characteristics include polymethyl methacrylate (PMMA) resin and polycarbonate (PC) resin. The above-mentioned polymethyl methacrylate resin is transparent and weather resistant. However, the heat resistance is not sufficient, and there is a problem that it is easily deformed under high temperature and high humidity. On the other hand, the polycarbonate resin has excellent heat resistance and impact resistance, but has a problem that it is inferior in scratch resistance and weather resistance.
[0004]
Further, these amorphous resins having transparency are inferior in oil resistance, and when exposed to gasoline, gear oil, etc., there is a problem that transparency is impaired and cracks are generated.
[0005]
On the other hand, as a translucent member of an illuminator, Japanese Patent Laid-Open No. 60-136791 discloses a method using a copolymer having a specific 6-membered cyclic acid anhydride unit and an aromatic vinyl compound unit. However, since the copolymer specifically disclosed in the publication contains a considerable amount of aromatic vinyl compound units, the heat resistance, oil resistance and scratch resistance are still insufficient, and the weather resistance is inferior. When exposed to the outdoors for a long time, there are problems such as a decrease in transparency and discoloration, and it has been difficult to divert this copolymer as a vehicle window material.
[0006]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to provide a vehicle window material that is excellent in transparency and heat resistance, and particularly excellent in oil resistance, scratch resistance, and weather resistance.
[0007]
[Means for Solving the Problems]
As a result of intensive studies to solve the above problems, the present inventors have found that a resin comprising a copolymer mainly composed of an unsaturated carboxylic acid alkyl ester unit and a glutaric anhydride unit has excellent transparency and heat resistance. It has been found that it has excellent properties and mechanical strength, is particularly excellent in oil resistance, weather resistance, and scratch resistance, and is useful as a window material for vehicles.
[0008]
That is, the present invention
[1] (i) a glutaric anhydride unit represented by the following general formula (1), (ii) a copolymer comprising an unsaturated carboxylic acid alkyl ester unit, or the units (i) and (ii) above (iii) a copolymer comprising an unsaturated carboxylic acid unit, or the above unit (i), (ii) or the above unit (i), (ii), (iii) and (iv) other not containing an aromatic ring Vehicle window material formed by molding a copolymer (A) comprising a vinyl monomer unit of
[0009]
[Formula 4]

[0010]
(In the above formula, R ¹ , R ² Represent the same or different hydrogen atoms or alkyl groups having 1 to 5 carbon atoms. )
[2] The vehicle window material according to [1], wherein the content of (i) glutaric anhydride in the copolymer (A) is 5 to 60% by weight,
[3] The vehicle window material according to [1] or [2], wherein the unsaturated carboxylic acid unit (iii) has a structure represented by the following general formula (2):
[0011]
[Chemical formula 5]

[0012]
(However, R ^Three Represents hydrogen or an alkyl group having 1 to 5 carbon atoms)
[4] The vehicle window material according to any one of [1] to [3], wherein the unsaturated carboxylic acid alkyl ester unit (ii) has a structure represented by the following general formula (3).
[0013]
[Chemical 6]

[0014]
(However, R ^Four Represents hydrogen or an alkyl group having 1 to 5 carbon atoms, R ^Five Represents an aliphatic or alicyclic hydrocarbon group having 1 to 6 carbon atoms, or an aliphatic or alicyclic hydrocarbon group having 1 to 6 carbon atoms and substituted with a hydroxyl group or halogen having a number of 1 to 5 carbon atoms. )
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the vehicle window material of the present invention will be specifically described.
[0016]
The copolymer used as the window material for vehicles according to the present invention includes (i) the following general formula (1):
[0017]
[Chemical 7]

[0018]
(In the above formula, R ¹ , R ² Represent the same or different hydrogen atoms or alkyl groups having 1 to 5 carbon atoms. )
A glutaric anhydride unit represented by: (ii) a copolymer comprising an unsaturated carboxylic acid alkyl ester monomer, or the above units (i) and (ii) and (iii) an unsaturated carboxylic acid unit. Or the above units (i) and (ii) or the above units (i), (ii) and (iii) and (iv) other vinyl monomer units not containing an aromatic ring. These are copolymers, and these can be used alone or in combination of two or more.
[0019]
Although there is no restriction | limiting in particular in the manufacturing method of the said copolymer used for this invention, It can manufacture by the method shown below fundamentally. That is, an unsaturated carboxylic acid monomer and an unsaturated carboxylic acid alkyl ester monomer that give the glutaric anhydride unit (i) represented by the general formula (1) by the subsequent heating step, and the aromatic ring When other vinyl monomer units (iv) not included are included, the copolymer is copolymerized with a vinyl monomer giving the units to obtain a precursor polymer (a), and then the precursor polymer (a) Can be produced by heating in the presence or absence of a suitable catalyst to carry out an intramolecular cyclization reaction by (a) dealcoholization and / or (b) dehydration. In this case, typically, the carboxyl group of the unsaturated carboxylic acid unit (iii) of 2 units is dehydrated by heating the precursor polymer (a), or the adjacent unsaturated carboxylic acid unit (iii) And 1 unit of the glutaric anhydride unit is generated by elimination of the alcohol from the unsaturated carboxylic acid alkyl ester unit (ii).
[0020]
There is no restriction | limiting in particular as an unsaturated carboxylic acid monomer used in this case, Any unsaturated carboxylic acid monomer which can be copolymerized with another vinyl compound can be used. As a preferable unsaturated carboxylic acid monomer, the following general formula (4)
[0021]
[Chemical 8]

[0022]
(However, R ^Three Represents hydrogen or an alkyl group having 1 to 5 carbon atoms)
In particular, acrylic acid and methacrylic acid are preferred, and methacrylic acid is more preferred from the viewpoint of excellent thermal stability. These can be used alone or in combination. In addition, the unsaturated carboxylic acid monomer represented by the general formula (4) gives an unsaturated carboxylic acid unit having a structure represented by the general formula (2) when copolymerized. Moreover, there is no restriction | limiting in particular as an unsaturated carboxylic-acid alkylester type monomer, However, As a preferable example, what is represented by following General formula (5) can be mentioned.
[0023]
[Chemical 9]

[0024]
(However, R ^Four Represents hydrogen or an alkyl group having 1 to 5 carbon atoms, R ^Five Represents an aliphatic or alicyclic hydrocarbon group having 1 to 6 carbon atoms, or an aliphatic or alicyclic hydrocarbon group having 1 to 6 carbon atoms and substituted with a hydroxyl group or halogen having a number of 1 to 5 carbon atoms. )
Among these, an acrylate ester and / or a methacrylic ester having an aliphatic or alicyclic hydrocarbon group having 1 to 6 carbon atoms or the hydrocarbon group having a substituent is particularly preferable. The unsaturated carboxylic acid alkyl ester monomer represented by the general formula (5) gives an unsaturated carboxylic acid alkyl ester unit having a structure represented by the general formula (3) when copolymerized.
[0025]
Preferable specific examples of the unsaturated carboxylic acid alkyl ester monomer include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, (meth ) T-butyl acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, chloromethyl (meth) acrylate, 2-chloroethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate , (Meth) acrylic acid 3-hydroxypropyl, (meth) acrylic acid 2,3,4,5,6-pentahydroxyhexyl and (meth) acrylic acid 2,3,4,5-tetrahydroxypentyl Of these, methyl methacrylate is most preferably used. These can be used alone or in combination of two or more thereof.
[0026]
In the production of the copolymer (A) used in the present invention, other vinyl monomers not containing an aromatic ring may be used as long as the effects of the present invention are not impaired. Preferable specific examples of other vinyl monomers not containing an aromatic ring include vinyl cyanide monomers such as acrylonitrile, methacrylonitrile, ethacrylonitrile, allyl glycidyl ether, maleic anhydride, itaconic anhydride, N-methylmaleimide, N-ethylmaleimide, N-cyclohexylmaleimide, acrylamide, methacrylamide, N-methylacrylamide, butoxymethylacrylamide, N-propylmethacrylamide, aminoethyl acrylate, propylaminoethyl acrylate, dimethylamino methacrylate Ethyl, ethylaminopropyl methacrylate, cyclohexylaminoethyl methacrylate, N-vinyldiethylamine, N-acetylvinylamine, allylamine, methallylamine, N-methylallyl Min, 2-isopropenyl - oxazoline, 2-vinyl - oxazoline, 2-acryloyl - and oxazoline and can be exemplified, and these alone to be able to use two or more kinds.
[0027]
When a vinyl monomer containing an aromatic ring is copolymerized, the scratch resistance, oil resistance, and weather resistance tend to decrease, so it is preferable not to copolymerize, but as long as the effect of the present invention is not impaired. There is no problem. Examples of the vinyl monomer containing an aromatic ring include N-phenylmaleimide and phenylaminoethyl methacrylate. In addition, the aromatic vinyl monomers such as styrene, α-methylstyrene, p-glycidylstyrene, p-aminostyrene, and 2-styryl-oxazoline are not copolymerized because the above characteristics tend to be deteriorated. Although it is preferable, in the case of copolymerization, it should be limited to less than 1% by weight.
[0028]
As for the polymerization method of the original polymer (a), known polymerization methods such as bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, etc., basically by radical polymerization, can be used, but there are fewer impurities. Particularly preferred are solution polymerization, bulk polymerization and suspension polymerization.
[0029]
Moreover, it is preferable that the raw polymer (a) is produced at a polymerization temperature of 90 ° C. or less in terms of colorless transparency after the heat treatment, and a more preferable polymerization temperature is 80 ° C. or less, particularly preferably 70 ° C. or less. It is. The lower limit of the polymerization temperature is not particularly limited as long as the polymerization proceeds, but is usually 50 ° C. or higher, preferably 60 ° C. or higher from the viewpoint of productivity considering the polymerization rate. The polymerization time is not particularly limited as long as it is a time sufficient to obtain a necessary polymerization rate, but is preferably in the range of 60 to 360 minutes, particularly preferably in the range of 90 to 180 minutes from the viewpoint of production efficiency.
[0030]
In the present invention, the preferred proportion of these monomer mixtures used in the production of the precursor polymer (a) is such that the monomer mixture is 100% by weight and the unsaturated carboxylic acid monomer is 15 to 50% by weight. %, More preferably 20 to 45% by weight, the unsaturated carboxylic acid alkyl ester monomer is preferably 50 to 85% by weight, more preferably 55 to 80% by weight, and does not contain a copolymerizable aromatic ring. When other vinyl monomers are used, the preferred ratio is 0 to 35% by weight.
[0031]
When the amount of the unsaturated carboxylic acid monomer is less than 15% by weight, the amount of glutaric anhydride units represented by the general formula (1) generated by heating the raw polymer (a) is reduced, There exists a tendency for the heat resistance improvement effect to become small. On the other hand, when the amount of the unsaturated carboxylic acid monomer exceeds 50% by weight, there is a tendency that a large amount of unsaturated carboxylic acid units remain after the cyclization reaction by heating the original polymer (a), and it is colorless. There is a tendency for transparency and retention stability to decrease.
[0032]
The method for producing a copolymer containing glutaric anhydride units by heating the precursor polymer (a) in the present invention and carrying out an intramolecular cyclization reaction by (i) dehydration and / or (b) dealcoholization, Although there is no restriction | limiting in particular, The method manufactured through the heated extruder which has a vent, and the method manufactured in the apparatus which can heat-devolatilize in nitrogen stream or under a vacuum are preferable. The temperature for the devolatilization by the above method is not particularly limited as long as it is a temperature at which an intramolecular cyclization reaction occurs due to (i) dehydration and / or (b) dealcoholization, but is preferably in the range of 180 to 300 ° C. In particular, a range of 200 to 280 ° C. is preferable. In addition, the time for heating and devolatilization at this time is not particularly limited, and can be set as appropriate according to the desired copolymer composition, but is usually preferably in the range of 1 minute to 60 minutes.
[0033]
Further, in the present invention, when the precursor polymer (a) is heated by the above method or the like, one or more of acid, alkali and salt compounds may be added as a catalyst for promoting the cyclization reaction to glutaric anhydride. it can. The addition amount is not particularly limited, and is preferably about 0.01 to 1 part by weight per 100 parts by weight of the original polymer (a). There are no particular restrictions on the types of these acids, alkalis, and salt compounds, and examples of the acid catalyst include hydrochloric acid, sulfuric acid, p-toluenesulfonic acid, phosphoric acid, phosphorous acid, phenylphosphonic acid, and methyl phosphate. It is done. Examples of the basic catalyst include metal hydroxides, amines, imines, alkali metal derivatives, alkoxides, ammonium hydroxide salts and the like. Furthermore, examples of the salt-based catalyst include metal acetates, metal stearates, metal carbonates, and the like. These catalysts can be added singly or in combination as long as the object of the present invention is not impaired.
[0034]
The content of the glutaric anhydride unit represented by the general formula (1) in the copolymer used in the present invention is preferably 5 to 60% by weight, more preferably 10 to 50% in the copolymer. % By weight. When the glutaric anhydride unit is less than 5% by weight, the effect of improving the heat resistance is small, and the scratch resistance (surface hardness) tends to decrease. In general, an infrared spectrophotometer is used for quantification of the glutaric anhydride unit. The glutaric anhydride unit is 1800cm ^-1 And 1760cm ^-1 Is characteristic and can be distinguished from unsaturated carboxylic acid units and unsaturated carboxylic acid alkyl ester units.
[0035]
The amount of unsaturated carboxylic acid units contained in the copolymer used in the present invention is 0 to 10% by weight, more preferably 0 to 5% by weight. Furthermore, it is most preferable in terms of colorless transparency that the unsaturated carboxylic acid unit is not substantially contained. When the unsaturated carboxylic acid unit exceeds 10% by weight, colorless transparency and residence stability tend to be lowered. The unsaturated carboxylic acid alkyl ester unit is preferably 40 to 95% by weight, more preferably 50 to 90% by weight, and the other vinyl monomer units not containing an aromatic ring are preferably 0 to 35% by weight. In addition, for quantification of each component contained in the copolymer of the present invention, a method by 1H-NMR can be used together with a method by the infrared spectrophotometer described above. For example, in the case of a copolymer consisting of a glutaric anhydride unit, methacrylic acid, and methyl methacrylate, the attribution of the spectrum is 0.5 to 1.5 ppm. The peak of methacrylic acid, methyl methacrylate, and glutaric anhydride ring compound Α-methyl group hydrogen, 1.6 to 2.1 ppm peak is methylene group hydrogen of polymer main chain, 3.5 ppm peak is methyl methacrylate carboxylate (-COOCH _Three ), The peak at 12.4 ppm can determine the copolymer composition from the carboxylic acid hydrogen of methacrylic acid and the integral ratio of the spectrum.
[0036]
Further, the intrinsic viscosity of such a copolymer is not particularly limited, but the intrinsic viscosity measured at 30 ° C. with a dimethylformamide solution with an Ubbelohde viscometer is preferably 0.1 to 0.7 dl / g, More preferably, it is 0.3-0.6 dl / g.
[0037]
Further, the copolymer used in the present invention has a glass transition temperature (Tg) of 120 ° C. or higher in a more preferable embodiment, and 140 ° C. or higher in a particularly preferable embodiment. Although there is no restriction | limiting in particular in an upper limit, A thing about 160 degreeC is obtained and can be used preferably. Since the copolymer used in the present invention has a high glass transition temperature as described above, it can be suitably used in terms of heat resistance as a vehicle window material used under severe weather conditions. In addition, the glass transition temperature here is a glass transition temperature (Tg) measured using a differential scanning calorimeter (DSC-7 type manufactured by Perkin Elmer).
[0038]
Moreover, it has been found that the copolymer used in the present invention has high surface hardness (pencil hardness) specifically, and has the highest level of scratch resistance among transparent resins. In this case, a surface hardness of 4H or more is obtained as a pencil hardness in a more preferred embodiment, particularly when the content of glutaric anhydride units is in a preferred range, and a surface hardness of 5H or more is obtained in a particularly preferred embodiment. The pencil hardness is measured according to JIS-K-5401 using a square plate molded product of 80 mm × 80 mm × 3 mm.
[0039]
Further, the vehicle window material of the present invention includes hindered phenol-based, benzotriazole-based, benzophenone-based, benzoate-based, and cyanoacrylate-based UV absorbers and antioxidants as long as the object of the present invention is not impaired. Fatty acids, acid esters and acid amides, lubricants and plasticizers such as higher alcohols, montanic acid and its salts, esters, half esters, stearyl alcohol, stellar amide and ethylene wax, release agents such as phosphorous acid Anti-coloring agents such as salts and hypophosphites, halogen-based flame retardants, phosphorus-based and silicone-based non-halogen-based flame retardants, nucleating agents, amine-based, sulfonic acid-based, polyether-based anti-static agents, pigments An additive such as a coloring agent may be optionally contained. However, it is necessary to add the color within a range in which the color of the additive does not adversely affect the window material and the transparency is not lowered.
[0040]
The method for mixing these additives is not particularly limited as long as these additives are sufficiently dispersed in the copolymer (A) used in the present invention. For example, a mixer, a kneader, a roll There are a method in which the resin is melted and kneaded with a Brabender, an extruder or the like, a method in which the resin is dissolved and dispersed in a suitable solvent, and the solvent is removed by a coagulation method, a casting method, or a direct drying method. When using an extruder, after kneading, it is usually pelletized with a strand cutter.
[0041]
The vehicle window material of the present invention is obtained as a resin plate or a resin sheet by molding the copolymer (A). Examples of the method for molding the resin plate include injection molding, press molding, and extrusion molding. Although the melting temperature of the resin at the time of molding depends on the type of the copolymer (A) used in the present invention, it is usually 100 to 400 ° C, preferably 200 to 350 ° C.
[0042]
Moreover, as a manufacturing method of a resin sheet, the T-die method, the casting method, and the hot press method are mentioned. In the case of the production method by the T-die method, an extruder type melt extruder equipped with a single-screw or twin-screw extruder can be used. The melt-kneading temperature for producing the resin sheet is preferably 150 to 350 ° C, more preferably 200 to 300 ° C, although it depends on the type of the copolymer (A) used in the present invention. Moreover, when melt-kneading using a melt-extrusion apparatus, it is preferable to perform the melt-kneading under reduced pressure or the melt-kneading under nitrogen stream from a viewpoint of coloring suppression. Moreover, when manufacturing a resin sheet by a hot press method, although depending on the kind of copolymer (A) used for this invention, preferable press temperature is 150-350 degreeC, More preferably, it is 200-300 degreeC.
[0043]
Moreover, although the thickness of a resin plate and a resin sheet is suitably determined according to the compatible part of the window material to be used, it is the range of 1-100 mm normally.
[0044]
Since the vehicle window material of the present invention has an extremely high surface hardness, the hard coat effect can be remarkably improved when the surface is subjected to a hard coat treatment, and as a vehicle window material in terms of scratch resistance. Is preferred.
[0045]
For the hard coat treatment of the window material, a hard coat agent comprising an acrylic resin system, a melamine resin system, a polysiloxane resin system or the like can be used according to a known method. As the hard coating method, known methods can be used, and examples thereof include a bar coating method, a dip coating method, a flow coating method, a spray coating method, a spin coating method, and a roller coating method.
[0046]
The vehicle window material thus obtained is excellent in transparency and heat resistance, especially in oil resistance, scratch resistance and weather resistance, so the rear side window of the automobile, the rear window, the sunroof window, the windshield of the motorcycle, etc. Can be used practically.
[0047]
【Example】
Hereinafter, the configuration and effects of the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples. Prior to the description of each example, various physical property measurement methods employed in the example will be described.
[0048]
(1) Transparency
Using a direct reading haze meter manufactured by Toyo Seiki Co., Ltd., the total light transmittance (%) and haze (cloudiness) (%) at 23 ° C. of a square plate molded product of 80 mm × 80 mm × 3 mm were measured, and the transparency Evaluated.
[0049]
(2) Heat resistance
Using a differential scanning calorimeter (DSC-7 manufactured by Perkin Elmer), the glass transition temperature (Tg) was measured at a heating rate of 20 ° C./min in a nitrogen atmosphere.
[0050]
(3) Rigidity
In accordance with ASTM D740, the flexural modulus was measured for 12.7 mm × 127 mm × 3 mm thick test specimens.
[0051]
(4) Surface hardness
The pencil hardness of a square plate molded product of 80 mm × 80 mm × 3 mm was measured according to JIS-K-5401.
[0052]
(5) Oil resistance
An 80 mm × 80 mm × 3 mm square plate molded product is immersed in gear oil (GEAR5 manufactured by Japan Energy Co., Ltd.), and the total light transmittance after the immersion treatment at 40 ° C. for 24 hours is measured by the method described in (1) above. The retention of total light transmittance before and after the treatment (total light transmittance after treatment (%) / total light transmittance after treatment (%) × 100) was calculated and used as an index of oil resistance.
[0053]
(6) Weather resistance
80 mm × 80 mm × 3 mm square plate molded article was measured for the total light transmittance after 1000 hours exposure treatment with a sunshine weather meter specified in JIS D0205 by the method described in the above (1), and the total light before and after the treatment The transmittance retention ((total light transmittance after treatment (%) / total light transmittance after treatment (%)) × 100) was calculated and used as an indicator of weather resistance.
[0054]
[Example 1]
In a stainless steel autoclave having a capacity of 20 liters and equipped with a baffle and a foudra-type stirring blade, a methyl methacrylate / acrylamide copolymer suspension (prepared by the following method: 20 parts by weight of methyl methacrylate, 80 parts by weight of acrylamide) Then, 0.3 parts by weight of potassium persulfate and 1500 parts by weight of ion-exchanged water are charged into the reactor, and the reactor is replaced with nitrogen gas and maintained at 70 ° C. The reaction completely converts the monomer into a polymer. Then, a solution obtained by dissolving 0.05 part of ion-exchanged water in 165 parts of ion-exchanged water is obtained and stirred at 400 rpm. The inside of the system was replaced with nitrogen gas. Next, the following mixed substances were added while stirring the reaction system, and the temperature was raised to 70 ° C. The time when the internal temperature reached 70 ° C. was set as the start of polymerization, and kept for 180 minutes to complete the polymerization. Thereafter, the reaction system was cooled, the polymer was separated, washed, and dried in accordance with ordinary methods to obtain a bead-shaped precursor polymer (a-1). The polymerization rate of this original polymer (a-1) was 98%.
Methacrylic acid (MAA) 25 parts by weight
75 parts by weight of methyl methacrylate (MMA)
0.6 parts by weight of t-dodecyl mercaptan
0.4 part by weight of 2,2′-azobisisobutyronitrile
This bead-shaped polymer (a-1) was supplied from the hopper port of a vented co-rotating twin-screw extruder (PCM-30 manufactured by Ikekai Tekko Co., Ltd.) having a screw diameter of 30 mm and an L / D of 25. It was melt-extruded at 250 ° C. and a screw rotational speed of 100 rpm to obtain a copolymer (A-1) containing pellet-like glutaric anhydride units. As a result of analyzing the obtained copolymer (A-1) using an infrared spectrophotometer, 1800 cm. ^-1 And 1760cm ^-1 The absorption peak was confirmed by this, and it confirmed that the glutaric anhydride unit had formed in this copolymer (A-1). In addition, this copolymer was dissolved in deuterated dimethyl sulfoxide, and the solution was at room temperature (23 ° C.). ¹ When H-NMR was measured and the copolymer composition was determined, it was 75% by weight of methyl methacrylate (MMA) units, 20% by weight of glutaric anhydride units, and 5% by weight of methacrylic acid (MAA) units. Moreover, the intrinsic viscosity of this copolymer (A-1) was 0.46 dl / g. About the obtained copolymer, it used for the injection molding machine (Toshiba machine company make, IS55EPN), each test piece was shape | molded and evaluated at the cylinder temperature of 250 degreeC and the mold temperature of 80 degreeC. Table 1 shows the results of measuring various physical properties.
[0055]
Next, the copolymer is subjected to an injection molding machine (FN1000-12H manufactured by Nissei Plastic Industries) and injection molded at a cylinder temperature of 250 ° C. and a mold temperature of 80 ° C. to obtain a window-shaped molded product of 300 mm × 300 mm × 3 mm. It was. An acrylic curable hard coat agent was applied to the window-shaped molded article by a dip coating method to form a hard coat layer. This window-shaped molded article was excellent in transparency, scratch resistance, oil resistance, and weather resistance, and no defects in the appearance of the molded article were observed. From this result, it was found that the window-shaped molded article of the present invention is useful as a vehicle window material.
[0056]
[Example 2]
Polymerization was carried out in the same manner as in Example 1 except that the monomer charge composition was changed to the following composition to obtain a bead-shaped precursor polymer (a-2). The polymerization rate of this original polymer (a-2) was 98%.
Methacrylic acid (MAA) 10 parts by weight
90 parts by weight of methyl methacrylate (MMA)
0.6 parts by weight of t-dodecyl mercaptan
0.4 part by weight of 2,2′-azobisisobutyronitrile
This bead-like polymer (a-2) is supplied from the hopper port of a vented co-rotating twin-screw extruder (PCM-30 manufactured by Ikegai Iron Works Co., Ltd.) having a screw diameter of 30 mm and an L / D of 25. It was melt-extruded at 250 ° C. and a screw rotation speed of 100 rpm to obtain a copolymer (A-2) containing pellet-like glutaric anhydride units. When the copolymer composition of the obtained copolymer (A-2) was determined in the same manner as in Example 1, 89% by weight of methyl methacrylate unit, 11% by weight of glutaric anhydride unit, 0% of methacrylic acid unit % By weight. Moreover, the intrinsic viscosity of this copolymer (A-2) was 0.44 dl / g. Table 1 shows the results of measuring various physical properties of the obtained copolymer, in which test pieces were prepared and evaluated in the same manner as in Example 1.
[0057]
Using the copolymer, a 300 mm × 300 mm × 3 mm window-shaped molded product was obtained by injection molding in the same manner as in Example 1. An acrylic curable hard coat agent was applied to the window-shaped molded article by a dip coating method to form a hard coat layer. This window-shaped molded article was excellent in transparency, scratch resistance, oil resistance, and weather resistance, and no defects in the appearance of the molded article were observed. From this result, it was found that the window-shaped molded article of the present invention is useful as a vehicle window material.
[0058]
[Comparative Example 1]
Except having changed the monomer preparation composition into the following composition, it superposed | polymerized similarly to Example 1 and obtained the bead-shaped base polymer (a-3). The polymerization rate of this original polymer (a-3) was 98%.
Methacrylic acid (MAA) 25 parts by weight
65 parts by weight of methyl methacrylate (MMA)
Styrene (St) 10 parts by weight
0.6 parts by weight of t-dodecyl mercaptan
0.4 part by weight of 2,2′-azobisisobutyronitrile
This bead-shaped polymer (a-3) was supplied from the hopper port of a vented co-rotating twin-screw extruder (PCM-30 manufactured by Ikegai Iron Works Co., Ltd.) having a screw diameter of 30 mm and an L / D of 25. It was melt-extruded at 250 ° C. and a screw rotation speed of 100 rpm to obtain a copolymer (A-3) containing pellet-like glutaric anhydride units. A glutaric anhydride unit is formed in the copolymer (A-3) by using an infrared spectrophotometer in the same manner as in Example 1 for the obtained copolymer (A-3). It was confirmed. In addition, this copolymer was dissolved in deuterated dimethyl sulfoxide, and the solution was at room temperature (23 ° C.). ¹ The H-NMR was measured, and the spectrum was assigned. The peak of 0.5 to 1.5 ppm was methacrylic acid, methyl methacrylate and hydrogen of α-methyl group of glutaric anhydride ring compound, 1.6 to 2.1 ppm. The peak of is the hydrogen of the methylene group of the polymer main chain, the peak of 2.4 ppm is the α-hydrogen of styrene, the peak of 3.5 ppm is the carboxylic acid ester of methyl methacrylate (—COOCH _Three ), The 7.2 ppm peak is the hydrogen of the benzene ring of styrene, the 12.4 ppm peak is the hydrogen of carboxylic acid of methacrylic acid, and the copolymer composition is determined from the integral ratio of the spectrum. It was 60% by weight, glutaric anhydride unit 20% by weight, methacrylic acid unit 5% by weight, and styrene unit 15% by weight. In addition, this copolymer (A-3) had an intrinsic viscosity of 0.45 dl / g. Table 1 shows the results of various physical properties measured by preparing and evaluating test pieces in the same manner as in Example 1 for the obtained copolymer.
[0059]
Further, using the above copolymer, a window-shaped molded product having a size of 300 mm × 300 mm × 3 mm was obtained by injection molding in the same manner as in Example 1. An acrylic curable hard coat agent was applied to the window-shaped molded article by a dip coating method to form a hard coat layer. Although this window-shaped molded article was excellent in transparency, it was inferior in oil resistance and weather resistance.
[0060]
[Comparative Example 2]
Table 1 shows various physical property measurement results obtained by preparing and evaluating test pieces in the same manner as in Example 1 using “Iupilon” S3000 manufactured by Mitsubishi Engineering Plastics, which is polycarbonate (PC).
[0061]
Further, using the above copolymer, a window-shaped molded product having a size of 300 mm × 300 mm × 3 mm was obtained by injection molding in the same manner as in Example 1. An acrylic curable hard coat agent was applied to the window-shaped molded article by a dip coating method to form a hard coat layer. This window-shaped molded article was inferior in oil resistance and weather resistance, and it was found that the performance as a vehicle window material was insufficient.
[0062]
[Comparative Example 3]
Table 1 shows various physical property measurement results obtained by preparing and evaluating test pieces in the same manner as in Example 1 using “SUMIPEX” LG manufactured by Sumitomo Chemical Co., which is polymethyl methacrylate (PMMA).
[0063]
Using the copolymer, a 300 mm × 300 mm × 3 mm window-shaped molded product was obtained by injection molding in the same manner as in Example 1. An acrylic curable hard coat agent was applied to the window-shaped molded article by a dip coating method to form a hard coat layer. This window-shaped molded article was inferior in oil resistance.
[0064]
[Table 1]

[0065]
By comparing Examples 1 and 2 and Comparative Examples 1 to 3, the specific copolymer used in the vehicle window material of the present invention has good transparency and heat resistance with respect to conventional materials such as PC and PMMA. It can be seen that the film has excellent scratch resistance, oil resistance, and weather resistance.
[0066]
On the other hand, the copolymer shown in Comparative Example 1 has good transparency and heat resistance, but is inferior in oil resistance and weather resistance and does not exhibit sufficient performance as a vehicle window material.
[0067]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a vehicle window material that is excellent in transparency and heat resistance, and particularly excellent in oil resistance, scratch resistance, and weather resistance.

Claims (4)

(i) a glutaric anhydride unit represented by the following general formula (1), (ii) a copolymer comprising an unsaturated carboxylic acid alkyl ester unit, or the above units (i) and (ii) and (iii) Copolymers consisting of unsaturated carboxylic acid units, or the above units (i), (ii) or the above units (i), (ii), (iii) and (iv) other vinyl systems not containing an aromatic ring The window material for vehicles formed by shape | molding the copolymer (A) which consists of a monomer unit.

(In the above formula, R ¹ and R ² represent the same or different hydrogen atoms or alkyl groups having 1 to 5 carbon atoms.) The vehicle window material according to claim 1, wherein the content of the (i) glutaric anhydride unit in the copolymer (A) is 5 to 60% by weight. The vehicle window material according to claim 1 or 2, wherein the unsaturated carboxylic acid unit (iii) has a structure represented by the following general formula (2).

(However, R ³ represents hydrogen or an alkyl group having 1 to 5 carbon atoms) The vehicle window material according to any one of claims 1 to 3, wherein the unsaturated carboxylic acid alkyl ester unit (ii) has a structure represented by the following general formula (3).

(However, R ⁴ represents hydrogen or an alkyl group having 1 to ⁵ carbon atoms, and R ⁵ represents an aliphatic or alicyclic hydrocarbon group having 1 to 6 carbon atoms, or a hydroxyl group or halogen having a number of 1 to ⁵ carbon atoms. A C1-C6 aliphatic or alicyclic hydrocarbon group substituted with