JP4601239B2 - Method for producing acrylic resin film - Google Patents

Description

Ｋ；最大加速度（ｍ／ｓ²）、ｒ；スクリーン振幅（ｍ）、ω；角速度（ｒａｄ/ｓｅｃ）
Ｎ；モーター回転数（ｒｐｍ）
例えば、スクリーン振幅３．５mm、モーター回転数１８００rpmの場合
Ｋ＝ ３．５×１０^-3×（２π × １８００／６０）² = １２４ｍ／ｓ² となる。
【００４０】
また、上記濾過装置は、直径をＸとする円形の濾材３を有し、この濾材３面に対する垂直方向の振幅長がＸ／６０〜Ｘ／２００であることが望ましい。垂直方向の振幅長がＸ／２００未満の場合は、濾材３上に残った凝集物の排出がされにくく、目詰まりを起こしやすくなる傾向にある。また、振幅がＸ／６０より大きいと濾材３に対する負荷が大きく、耐久性が短くなりやすい。
【００４１】
濾材３は、ステンレス鋼、あるいはポリエステル製の繊維で形成されていることが好ましく、特にステンレス鋼が好ましい。それは、上述した水洗装置による濾材３の洗浄において、ステンレス鋼材では比較的水圧を高くでき、目詰まりの防止効果を上げることができるためである。
また、濾材３の線径は１０〜７０μｍであることが好ましい。線径が１０μｍより小さい場合は、濾材３の強度が弱いため破れを起こしやすい。一方、７０μｍより太いと、開口度が小さくなり濾過面積が狭くなるため、濾過効率が悪くなる傾向を示すためである。
【００４２】
上記濾材３は、その目の大きさが１００から６００メッシュであることが好ましく、より好ましくは１５０〜４００メッシュである。目の大きさが１００メッシュより大きい場合は、乳化ラテックス中に含まれる凝集物及び浮遊物等の固形物が、濾過したアクリル樹脂ラテックス中に混入しやすくなるため、このアクリル樹脂ラテックスから得たポリマーを用いた樹脂成型板やフィルムに、ブツやフィッシュアイが発生しやすくなる傾向にある。一方、目の大きさが６００メッシュを超えた範囲では、濾材３の目詰まりが起こりやすくなる傾向にある。
【００４３】
また、本発明で用いられる濾過装置は、図２に示すように、水流により濾材３の表面を洗浄できる水洗装置１０が付設されている。また、この濾過装置は、上述した濾過装置と基本的な構造は同じであるため、水洗装置のみについて説明する。
上記水洗装置の一例としては、濾材３を洗浄する水（洗浄水）を濾材３に対して吹きつけるノズル１６と、このノズル１６が設けられている円形導水管１７と、水洗装置を固定するための接合部１８と、円形導水管１７と接合部１８を連結している連結部１９と、水洗装置外部から水を導入する導水管２０とから概略構成された水洗装置を用いることができる。
上記水洗装置は、装置外部から導水管２０に導入された水が、接合部１８内に設けられた導管（図示略）を通って、連結部１９内に設けられた導管（図示略）を通り、更に円形導水管１７内に供給され、ノズル１６から濾材３に吹き付けられるようになっている。
【００４４】
上記ノズル１６から噴射される水は、０．０１〜２．０ＭＰａの圧力で濾材３のアクリル樹脂ラテックスを濾過する側の面に対して吹き出され、これにより濾材３の細部にある異物が除かれ、安定的に目詰まりを防止できる。ノズル１６から噴射される水の圧力が０．０１ＭＰａ未満の場合、圧力が低く、目詰まりの防止効果が少ない。また、２．０ＭＰａを超えると、濾材３の耐久性を損なう恐れがあるため好ましくない。
【００４５】
このような濾過装置を用いて濾過を行うことにより、濾材３上に残った凝集物等の除去作業の必要がなくなり、濾材３が破損して交換する頻度を少なくすることができるため、多層構造重合体を含有するアクリル樹脂ラテックスの濾過を連続的に行うことが可能となる。
また、上記の水洗装置により、濾材３の微細な網目構造の目の中に残留した凝集物が除去されるため、安定に濾材３の目詰まりを防止することができる。
また、水洗装置から濾材３に対して水を吹き付ける間、濾材３を円運動及び振幅運動させておけば、濾材３の全面にまんべんなく水を吹き付けることができるので、洗浄効果が向上する。
【００４６】
以下、本発明のアクリル樹脂フィルムの製造方法について説明する。
本発明のアクリル樹脂フィルムの製造方法は、まず多層構造重合体を含有するアクリル樹脂ラテックスを製造し、これを上述した濾過装置を用いて濾過後、その濾液を凝析して多層構造重合体を回収して、これをフィルム状に成形する。
【００４７】
多層構造重合体を含有するアクリル樹脂ラテックスの製造方法としては、例えば、多層構造重合体の中心部分となる最内重合体（Ａ）を与える炭素数１〜８のアルキル基を有するアルキルアクリレート及び／又は炭素数１〜４のアルキル基を有するアルキルメタクリレート（Ａ１）、及びグラフト交叉剤（Ａ２）を少なくとも含む単量体混合物を供給し、重合した後、架橋弾性重合体（Ｂ）層、中間重合体（Ｄ）層、及び最外重合体（Ｃ）層を与える単量体、あるいは単量体混合物をそれぞれ順に反応容器に供給し、多層構造重合体を重合して、アクリル樹脂ラテックスを得る方法がある。
また、多層構造重合体の中心部分となる最内重合体（Ａ）を与える炭素数１〜８のアルキル基を有するアルキルアクリレート及び／又は炭素数１〜４のアルキル基を有するアルキルメタクリレート（Ａ１）、及びグラフト交叉剤（Ａ２）を少なくとも含む単量体混合物を水および界面活性剤と混合して、乳化液を調製し、該乳化液を反応容器に供給し、重合した後、架橋弾性重合体（Ｂ）層、中間重合体（Ｄ）層、及び最外重合体（Ｃ）層を与える単量体、あるいは単量体混合物をそれぞれ順に反応容器に供給し、多層構造重合体を重合して、アクリル樹脂ラテックスを得る方法がある。
【００４８】
上記乳化液を調製する方法としては、攪拌翼を備えた攪拌機、ホモジナイザー、ホモミキサー等の各種強制乳化装置、膜乳化装置等の混合装置に、水と単量体混合物を仕込んだ後、界面活性剤を投入する方法、混合装置に水と界面活性剤を仕込んだ後、単量体混合物を投入する方法、混合装置に単量体混合物と界面活性剤を仕込んだ後、水を投入する方法等が挙げられる。これらのうち、水中に単量体混合物を仕込んだ後、界面活性剤を投入する方法、及び水中に界面活性剤を仕込んだ後、単量体混合物を投入する方法が、上述した多層構造重合体を得る方法として好適である。
【００４９】
乳化液を調製する際の単量体混合物と水との質量比としては、単量体混合物１００部に対し水１０〜５００部が好ましく、より好ましくは、単量体混合物１００部に対し水１００〜３００部である。
【００５０】
乳化液の調製に使用される界面活性剤としては、アニオン系、カチオン系、ノニオン系の界面活性剤が使用できるが、特にアニオン系の界面活性剤が好ましい。アニオン系界面活性剤としては、ロジン酸石鹸、オレイン酸カリウム、ステアリン酸ナトリウム、ミリスチン酸ナトリウム、Ｎ−ラウロイルザルコシン酸ナトリウム、アルケニルコハク酸ジカリウム系等のカルボン酸塩、ラウリル硫酸ナトリウム等の硫酸エステル塩、ヂオクチルスルホコハク酸ナトリウム、ドデシルベンゼンスルホン酸ナトリウム、アルキルジフェニルエーテルジスルホン酸ナトリウム系等のスルホン酸塩、ポリオキシエチレンアルキルフェニルエーテルリン酸ナトリウム系等のリン酸エステル塩等が挙げられる。
【００５１】
また、乳化液は、Ｗ／Ｏ型、Ｏ／Ｗ型のいずれの分散構造でも使用することができるが、特に水中に単量体混合物の油滴が分散したＯ／Ｗ型で、分散相の油滴の直径が１００μｍ以下であることが好ましく、さらに好ましくは５０μｍ以下、さらに好ましくは１５μｍ以下である。分散相の油滴の直径が１００μｍを超えると、得られるアクリル樹脂ラテックス中に含まれる１〜２００μｍの範囲に分布する巨大なポリマー粒子の数が増える傾向にあるため好ましくない。
【００５２】
このようにして調製された乳化液を用いて、多層構造重合体を含有するアクリル樹脂ラテックスを製造するには、例えば、反応容器に重合開始剤を投入して、重合温度まで昇温した後、最内重合体（Ａ）を形成する乳化液を供給して重合する。
次いで、過酸化物等の重合開始剤を含む架橋弾性重合体（Ｂ）層、中間重合体（Ｄ）層および最外重合体（Ｃ）層を与える単量体、あるいは単量体混合物を順次、反応容器に供給して、多層構造重合体を含有するアクリル樹脂ラテックスを製造することができる。
【００５３】
上記重合開始剤としては、公知のものが使用できるが、その具体例としては、過酸化物、アゾ系開始剤、又は酸化剤・還元剤を組み合わせたレドックス系開始剤が挙げられる。また、これらの中でもレドックス系開始剤が好ましく、特に硫酸第一鉄・エチレンジアミン四酢酸二ナトリウム塩・ロンガリット・ヒドロパーオキサイドを組み合わせたスルホキシレート系開始剤が好ましい。
【００５４】
以上説明したように、最内重合体（Ａ）を形成する上記乳化液を反応容器に供給し重合した後、架橋弾性重合体（Ｂ）、中間重合体（Ｄ）層、最外重合体（Ｃ）層を構成する単量体、あるいは単量体混合物をそれぞれ順に反応容器に供給して、多層構造重合体を重合する方法では、アクリル樹脂ラテックス中に存在する１〜２００μｍの範囲に分布する巨大ポリマー粒子を低減することができるため、印刷性に優れたアクリル樹脂フィルムを製造することができる。
【００５５】
このようにして得られた多層構造重合体を含有するアクリル樹脂ラテックスは、上述した濾過装置によって、その中に含まれる凝集物や浮遊物が除去される。以下、図１を用いて、アクリル樹脂ラテックスの濾過方法について説明する。
例えば、送液ポンプ（図示略）などで、多層構造重合体を含有するアクリル樹脂ラテックスをラテックス供給管２に送り、その吐出口２ａから濾材３上に供給する。この際、流量制御装置や制御弁（図示略）によって、アクリル樹脂ラテックスの流量を適当に調整することができる。そして、濾材３を透過した濾液、即ち凝集物や浮遊物が除去されたアクリル樹脂ラテックスを、ボトムボウル５により回収することができる。
【００５６】
濾過条件としては、流速０．１〜２０ｍ³／Ｈとし、濾材３による円運動及び振幅運動をアクリル樹脂ラテックスに与える加速度が５０ｍ／ｓ²以上になるように設定することが好ましい。また、濾材３面に対する垂直方向の振幅長の好ましい範囲は、Ｘ／６０〜Ｘ／２００（Ｘは、濾材３の直径を示す）であり、水平方向の円運動の好ましい回転数の範囲は、６０×（５０／（Ｘ／６０））^1/2／２πｒｐｍ以上である。
このように濾過処理を行うことによって、短時間での目詰まりを防止でき、濾過性を損なうことなく、アクリル樹脂フィルムの品質に悪影響を及ぼす巨大ポリマー等を除去することができるので、フィッシュアイ等を低減し、印刷性に優れたアクリル樹脂フィルムを製造することができる。
【００５７】
上記のように濾過処理を施したアクリル樹脂ラテックス中から多層構造重合体を回収する方法としては、特に限定されないが、塩析、酸析凝固、噴霧乾燥、又は凍結乾燥等が挙げられ、これらの方法により、多層構造重合体は粉状で回収される。
【００５８】
上記多層構造重合体からアクリル樹脂フィルムを成形する方法としては、特に限定されるものではないが、公知の溶液流延法、Ｔダイ法、インフレーション法等の溶融押出法等が挙げられ、これらの中でも、Ｔダイ法が経済性の点で最も好ましい。
【００５９】
上記のようにして製造されるアクリル樹脂フィルムには、必要に応じて、一般の配合剤を添加することができる。上記配合剤としては、例えば、安定剤、滑剤、加工助剤、可塑剤、耐衝撃助剤、発泡剤、充填剤、抗菌剤、防カビ剤、発泡剤、離型剤、帯電防止剤、着色剤、艶消剤、紫外線吸収剤等を挙げることができる。特に基材の保護の点では、耐候性を付与するために、紫外線吸収剤を添加することが好ましい。
【００６０】
紫外線吸収剤を添加する場合は、その分子量は３００以上であることが好ましく、特に好ましくは４００以上である。分子量が３００より小さな紫外線吸収剤を使用すると、フィルムを製造する際に転写ロール等に揮発し、ロール汚れを発生させることがある。
また、紫外線吸収剤の種類は、特に限定されないが、分子量４００以上のベンゾトリアゾール系または分子量４００以上のトリアジン系のものが特に好ましく使用でき、前者の具体例としては、商品名チヌビン２３４（チバガイギー社製）、商品名アデカスタブＬＡ−３１（旭電化工業社製）、後者の具体例としては、商品名チヌビン１５７７（チバガイギー社製）等が挙げられる。
【００６１】
配合剤の添加方法としては、多層構造重合体を用いてフィルムを製膜するための製膜機に、多層構造重合体とともに供給する方法と、予め多層構造重合体に配合剤を添加した混合物を各種混練機にて混練混合する方法がある。後者の方法に使用する混練機としては、通常の単軸押出機、二軸押出機、バンバリミキサー、ロール混練機等が挙げられる。
【００６２】
本発明の製造方法によれば、フィッシュアイが少ないアクリル樹脂フィルムを製造することが可能ため、特に印刷抜けが発生し易い印圧の低い淡色の木目柄やメタリック調、漆黒調等の全面（ベタ塗り）のグラビア印刷を施した場合でも、印刷抜けが少なく、従来知られている多層構造重合体を原料として使用したアクリル樹脂フィルムでは決して得られない高いレベルの印刷性を有する。
一般に、グラビア印刷を施した時の印刷抜けの数が２０個/ｍ²以下の場合は、意匠性の観点より各種工業用途への使用が可能となるが、特に高いレベルの意匠性が必要となる車両内装用表皮用途等では、印刷抜けの数が１個/ｍ²以下であることが印刷フィルムに求められる。本発明の製造方法によれば、印刷抜けの発生しやすい全面（ベタ刷り）印刷等の条件でも、印刷抜けの数が１個/ｍ²以下のアクリル樹脂フィルムが得られるため、高いレベルの意匠性付与が可能であり、工業的利用価値が極めて高い。
【００６３】
本発明の製造方法によって得られるアクリル樹脂フィルムには、各種基材に意匠性を付与するために、必要に応じて適当な印刷法により印刷を施し使用することできる。この場合、アクリル樹脂フィルムに片側印刷処理を施したものを用いることが好ましく、印刷面を基材樹脂との接着面に配する裏面印刷が、印刷面の保護や高級感の付与の点から好ましい。
また、基材の色調を生かし、透明な塗装の代替として用いる場合には、透明のまま使用することができる。特に、このように基材の色調を生かす用途に対し、アクリル樹脂フィルムは、ポリ塩化ビニルフィルムやポリエステルフィルムに比べ、透明性、深み感や高級感の点で優れている。
【００６４】
また、本発明の製造方法で得られたアクリル樹脂フィルムは、基材に積層することもできる。
積層する基材としては、各種樹脂成形品、木工製品および金属成形品が挙げられる。また、樹脂成形品のうち、本発明のアクリル樹脂フィルムと溶融接着可能な熱可塑性樹脂成形品としては、ＡＢＳ樹脂、ＡＳ樹脂、ポリスチレン樹脂、ポリカーボネート樹脂、塩化ビニル樹脂、アクリル樹脂、ポリエステル系樹脂、あるいはこれらを主成分とする樹脂が挙げられるが、接着性の点でＡＢＳ樹脂、ＡＳ樹脂、ポリカーボネート樹脂、塩化ビニル樹脂あるいはこれらの樹脂を主成分とする樹脂が好ましい。ただし、ポリオレフィン樹脂等の熱融着しない基材樹脂でも接着性の層を用いることでアクリル樹脂フィルムと基材を接着させることは可能である。
【００６５】
本発明のアクリル樹脂フィルムを表面に有する積層体の製造において、２次元形状の積層体に成形する場合は、熱融着できる基材に対しては熱ラミネーション等の公知の方法を用いることができる。また、熱融着しない基材に対しては、接着剤を介して貼り合わせることが可能である。
【００６６】
また、３次元形状の積層体に成形する場合は、予め形状加工したアクリル樹脂フィルムを射出成形用金型に挿入するインサート成形法や、金型内で真空成形後、射出成形を行うインモールド成形法等の公知の成形方法を用いることができる。インモールド成形法は、フィルムを加熱した後、真空引き機能を持つ型内で真空成形を行う。この方法によると、フィルムの成形と射出成形を一工程で行えるため、作業性、経済性の点から好ましい。
加熱温度としては、アクリル樹脂フィルムが軟化する温度以上、通常７０℃以上であることが望ましい。これはアクリル樹脂フィルムの熱的性質、あるいは成形品の形状に左右される。また、あまり温度が高いと表面外観が悪化したり、離型性が悪くなる。これもフィルムの熱的性質、あるいは成形品の形状に左右されるが、通常１７０℃以下であることが好ましい。
インモールド成形法は、このように真空成形で三次元形状を付与した後、射出成形により、アクリル樹脂フィルムと基材樹脂を溶融一体化させることで、表層にアクリル樹脂フィルム層を有するアクリル積層成形品を得ることができる。
【００６７】
また、本発明の製造方法で得られるアクリル樹脂フィルムは、必要に応じて、各種機能付与のための表面処理を施すことができる。
機能付与のための表面処理としては、シルク印刷、インクジェットプリント等の印刷処理、金属調付与あるいは反射防止のための金属蒸着、スパッタリング、湿式メッキ処理、表面硬度向上のための表面硬化処理、汚れ防止のための撥水化処理あるいは光触媒層形成処理、塵付着防止、あるいは電磁波カットを目的とした帯電防止処理、反射防止層形成、防眩処理等が挙げられる。
【００６８】
また、本発明の製造方法で得られるアクリル樹脂フィルムの別の用途として、液晶ディスプレイ等の偏光板に使用される偏光膜保護フィルム、あるいは視野角補償、位相差補償のための位相差板に使用される位相差フィルムがある。これら偏光膜保護フィルム、及び位相差フィルムにおいては、光学的な均一性、透明性と同時に光学的欠陥となるフィッシュアイ由来の光学歪がないことが必要であり、本発明の製造方法で得られるアクリル樹脂フィルムは、従来にない高いレベルの低フィッシュアイ数を生かし、上記光学用フィルムへの使用が可能となる。
【００６９】
また、本発明の製造方法により得られるアクリル樹脂フィルムを表面に有する積層体の別の工業的利用分野として、道路標識、表示板あるいは視認性を目的とした安全器具に使用される高輝度反射材がある。
高輝度反射材の種類としては、アルミニウム蒸着を施したガラスビーズを基材に埋め込んだカプセル型反射材、プリズム加工した樹脂シートを反射体として使用したプリズム型反射材等があり、いずれのタイプにおいても、上述した多層構造重合体を使用したアクリル樹脂フィルムは、反射材の表面に積層して使用する保護フィルムとして好適に用いることができる。
即ち、本発明の製造方法で得られるアクリル樹脂フィルムを表面に有する高輝度反射材は、フィッシュアイに由来する高輝度反射材の視認性の低下が少ないため、高輝度反射材の保護フィルムとして工業的利用価値が極めて高い。
【００７０】
【実施例】
実施例を用いて本発明を詳細に説明する。尚、製造例中の「部」は「質量部」を「％」は「質量％」をそれぞれ表す。また、略号は以下の通りである。
ＭＭＡはメチルメタクリレート、ＢＡはブチルアクリレート、ＡＭＡはアリルメタクリレート、１．３ＢＤは１.３−ブチレングリコールジメタクリレート、ｔＢＨはｔ−ブチルハイドロパーオキサイド、ＣＨＰはクメンハイドロパーオキサイド、ｎＯＭはｎ−オクチルメルカプタンを示す。
乳化剤（１）：モノ（ポリオキシエチレンノニルフェニルエーテル）リン酸４０％とジ（ポリオキシエチレンノニルフェニルエーテル）リン酸６０％混合物の水酸化ナトリウム部分中和物（商品名「フォスファノールＬＯ５２９」、東邦化学（株）製）。
【００７１】
後述する製造例で得られた多層構造重合体、アクリル樹脂ラテックス、及びアクリル樹脂フィルムについて、以下の試験法により諸物性を評価した。
（１） 固形分濃度の測定
アクリル樹脂ラテックス中の固形分は、アクリル樹脂ラテックス３０ｍｌをギアオーブン（３００℃）で３０分間乾燥させて、固形分を測定して求めた。
【００７２】
（２） 平均粒子径の測定
多層構造重合体の平均粒子径は、吸光度法により求めた。
（３）凝集物量の測定
ラテックス中の凝集物量は、ラテックス１００ｍｌを３３０メッシュのナイロンフィルターで濾過し、濾材上に残った濾過物の質量を測定することで求めた。
【００７３】
（４）濾過状況
濾過を１２時間連続して実施し、運転安定性から判断した。
◎：濾材の状態が、濾過開始直後と変化なく、極めて良好
○：濾材上に若干泡があるが濾過性に変化無く良好
×：濾過不能
【００７４】
（５）乳化液中の分散相の数平均粒子径測定
ガラス板上に乳化液を１滴滴下し、光学顕微鏡にて乳化液中の分散相２０個の直径を計測し、これらの平均値より平均粒子径を求めた。
【００７５】
（６）多層構造重合体のゲル含有率
秤量した多層構造重合体をアセトン溶媒中還流下で抽出処理、この処理液を遠心分離により分別、固形分を乾燥後、質量測定（抽出後質量）し、以下の式にて求めた。
ゲル含有率（％）＝（抽出前質量（ｇ）−抽出後質量（ｇ））／抽出前質量（ｇ）
（７）フィルム組成物の熱変形温度
フィルム組成物のペレットを、射出成形にてＡＳＴＭ Ｄ６４８にもとづく熱変形温度測定試片に成形し、８０℃で２４時間アニール後、低荷重（０．４５ＭＰａ）でＡＳＴＭ Ｄ６４８に従って測定した。
【００７６】
（８）フィルムの全光線透過率および曇価
ＪＩＳ Ｋ６７１４に従って評価した。
（９）フィルムの表面光沢
フィルムの表面光沢は、グロスメーター（ムラカミカラーリサーチラボラトリー製 ＧＭ−２６Ｄ型）を用い、６０゜での表面光沢を測定した。
【００７７】
（１０）フィッシュアイ数
厚さ０．１２５ｍｍのフィルム１ｍ²中のフィッシュアイ数を、高速・高機能表面欠陥検査装置ＬＳＣ−１００（三菱レイヨン（株）製）で、光の透過率が７５％以下となる１画素（０．４ｍｍ×０．５ｍｍ）以上の数を測定。
（１１）印刷抜け数
フィルムに黒色全面（ベタ刷り）のグラビア印刷を行い、２０ｍ²のフィルム中の印刷抜けした数を目視にて測定し、１ｍ²当たりの印刷抜け個数を求めた。
【００７８】
（多層構造重合体を含有するアクリル樹脂ラテックス（１）の製造）
冷却器付き重合容器内に、イオン交換水１９５部を投入し、７０℃に昇温し、さらに、イオン交換水５部にソジウムホルムアルデヒドスルホキシレート０.２０部、硫酸第一鉄０．０００１部、ＥＤＴＡ０．０００３部を加えて調製した混合物を一括投入した。
次いで、窒素下で撹拌しながら、ＭＭＡ０．３部、ＢＡ４．５部、ＢＤ０.２部、ＡＭＡ０.０５部、ＣＨＰ０.０２５部からなる単量体混合物および乳化剤（１）１．３部からなる混合物を８分間かけて重合容器に滴下した後、１５分間反応を継続させ、最内重合体（Ａ−１）の重合を完結した。
続いて、ＭＭＡ１.５部、ＢＡ２２.５部、ＢＤ１.０部、ＡＭＡ０.２５部からなる単量体混合物をＣＨＰ０.０１６部と共に９０分間で添加した後、６０分間反応を継続させ、架橋弾性重合体（Ｂ−１）層を形成させた。
続いて、ＭＭＡ６部、ＢＡ４部、ＡＭＡ０.０７５部、およびＣＨＰ０.０１２５部の混合物を４５分間かけて重合容器に滴下した後、６０分間反応を継続させ、中間重合体（Ｄ−１）層を形成させた。
続いて、ＭＭＡ５５.２部、ＢＡ４．８部、ｎ−ＯＭ０.１９部、およびｔ−ＢＨ０.０８部からなる単量体混合物を１４０分間かけて重合容器に滴下した後、６０分間反応を継続させ、最外重合体（Ｃ−１）層を形成し、多層構造重合体を含有するアクリル樹脂ラテックス（１）を得た。
【００７９】
（多層構造重合体を含有するアクリル樹脂ラテックス（２）の製造）
攪拌機を備えた容器に、イオン交換水８．５部を仕込んだ後、ＭＭＡ０．３部、ＢＡ４．５部、ＢＤ０.２部、ＡＭＡ０.０５部、ＣＨＰ０.０２５部からなる単量体混合物を投入し、攪拌混合した。そこに乳化剤（１）１．３部を攪拌しながら投入し、更に２０分間攪拌を継続し、乳化液（Ｎ−２）を調整した。得られた乳化液中の分散相の平均粒子径は１０μｍであった。
次に、冷却器付き重合容器内に、イオン交換水１８６．５部を投入し、７０℃に昇温し、さらに、イオン交換水５部にソジウムホルムアルデヒドスルホキシレート０.２０部、硫酸第一鉄０．０００１部、ＥＤＴＡ０．０００３部を加えて調製した混合物を一括投入した。
続いて、窒素下で撹拌しながら、乳化液（Ｎ−２）を８分間かけて重合容器に滴下した後、１５分間反応を継続させ、最内重合体（Ａ−２）の重合を完結した。
続いて、ＭＭＡ１.５部、ＢＡ２２.５部、ＢＤ１.０部、ＡＭＡ０.２５部からなる単量体混合物をＣＨＰ０.０１６部と共に９０分間で添加した後、６０分間反応を継続させ、架橋弾性重合体（Ｂ−２）層を形成させた。
続いて、ＭＭＡ６部、ＢＡ４部、ＡＭＡ０.０７５部、およびＣＨＰ０.０１２５部の混合物を４５分間かけて重合容器に滴下した後、６０分間反応を継続させ、中間重合体（Ｄ−２）層を形成させた。
続いて、ＭＭＡ５５.２部、ＢＡ４．８部、ｎ−ＯＭ０.１９部、およびｔ−ＢＨ０.０８部からなる単量体混合物を１４０分間かけて重合容器に滴下した後、６０分間反応を継続させ、最外重合体（Ｃ−２）層を形成し、多層構造重合体を含有するアクリル樹脂ラテックス（２）を得た。
【００８０】
（製造例１）
濾材にステンレス鋼製のメッシュ（線径 ５０μｍ、２３５メッシュ）を取り付けた図１の構成を有する濾過装置を用いて、アクリル樹脂ラテックス（１）を１２時間、流速３ｍ^３／Ｈで濾過した。この際、振幅長５．０ｍｍの振幅運動、回転数を１０００ｒｐｍの円運動により、濾材３上に残った凝集物に与える加速度を５５ｍ／ｓ^２に調整した。本製造例で得られた多層構造重合体の評価、濾過後のアクリル樹脂ラテックスの諸物性を表１に示す。なお、濾材３は、直径６００ｍｍであり、後述の製造例２〜８においても、同じ大きさの濾材３を使用した。
また、上記のごとく濾過して得られたアクリル樹脂ラテックス（１）に含有される多層構造重合体を酢酸カルシウム３部含む水溶液中で塩析させ、水洗回収後、乾燥し、粉体状の多層構造重合体を得た。多層構造重合体のゲル含有率は、６０％であった。
【００８１】
次に、上記多層構造重合体１００部、配合剤として、アデカスタブＬＡ−３１ＲＧ（旭電化（株）製）２．１部、アデカスタブＡＯ−５０（旭電化（株）製）０.１部、アデカスタブＬＡ−５７（旭電化（株）製）０．３部を添加した後、ヘンシェルミキサーを用いて混合し、この混合物を２３０℃に加熱した脱気式押出機（池貝鉄工（株）製ＰＣＭ−３０）に供給し、混練してペレットを得た。得られたペレットの熱変形温度の結果を表１に示す。
上記の方法で製造したペレットを８０℃で一昼夜乾燥し、３００ｍｍ幅のＴダイを取り付けた４０ｍｍφのノンベントスクリュー型押出機（Ｌ／Ｄ＝２６）を用いて、シリンダー温度２００℃〜２４０℃、Ｔダイ温度２５０℃、冷却ロール温度７０℃で、５０μｍ厚みのアクリル樹脂フィルムを製膜した。得られたアクリル樹脂フィルムの諸物性を表１に示す。
【００８２】
（製造例２）
アクリル樹脂ラテックス（１）の代わりに、アクリル樹脂ラテックス（２）を用いたこと以外は、製造例１と同様の方法で、アクリル樹脂フィルムを得た。
本製造例で得られた多層構造重合体の評価、濾過後のアクリル樹脂ラテックス、及びアクリル樹脂フィルムの諸物性を表１に示す。
【００８３】
（製造例３）
濾材にポリエステル製のメッシュ（線径 ５０μｍ、２３５メッシュ）を取り付けた図１の装置を用い、アクリル樹脂ラテックス（１）を１２時間、流速３ｍ^３／Ｈで濾過した。その際、濾材３の振幅長を３．５ｍｍ、回転数を１７００ｒｐｍとし、凝集物に与える加速度を１１１ｍ／ｓ^２に調整した以外は、製造例１と同様の方法で、アクリル樹脂フィルムを得た。
本製造例で得られた多層構造重合体の評価、濾過後のアクリル樹脂ラテックス、及びアクリル樹脂フィルムの諸物性を表１に示す。
【００８４】
（製造例４）
濾材にポリエステル製のメッシュ（線径 ４８μｍ、２８２メッシュ）を取り付けた図１の構成を有する濾過装置を用いて、アクリル樹脂ラテックス（１）を１２時間、流速３ｍ^３／Ｈで濾過した。この際、振幅長３．５ｍｍの振幅運動、及び回転数１２００ｒｐｍの円運動により、濾材３上に残った凝集物に与える加速度を５５ｍ／ｓ^２に調整した以外は製造例１と同様の方法により、アクリル樹脂フィルムを得た。
本製造例で得られた多層構造重合体の評価、濾過後のアクリル樹脂ラテックス、及びアクリル樹脂フィルムの諸物性を表１に示す。
【００８５】
（製造例５）
濾材にステンレス鋼製のメッシュ（線径５０μｍ、２３５メッシュ）、及び濾材上部に水洗装置を取り付けた図２の構成を有する濾過装置を用い、アクリル樹脂ラテックス（１）を１２時間、流速３ｍ^３／Ｈで、定期的に水洗（各ノズルの水圧０．７ＭＰａ、５分間隔で１０秒間水洗）しながら濾過した。この際、振幅長５．０ｍｍの振幅運動、及び回転数１０００ｒｐｍの円運動により、濾材３上に残った凝集物に与える加速度を５５ｍ／ｓ^２に調整して、多層構造重合体の評価、濾過後のアクリル樹脂ラテックス（１）の諸物性を調べた。その結果を表１に示す。
また、上記のごとく濾過して得られたアクリル樹脂ラテックス（１）を用いて、製造例１と同様の方法で、アクリル樹脂フィルムを得た。得られたアクリル樹脂フィルムの諸物性を表１に示す。
【００８６】
（製造例６）
多層構造重合体を含有するアクリル樹脂ラテックス（１）の製造において、最外重合体（Ｃ−１）層を形成させるのに使用する単量体混合物をＭＭＡ５８.２部、ＢＡ１．８部、ｎ−ＯＭ０.１９部、及びｔ−ＢＨ０.０８部に変更する以外は、同様の方法で乳化重合を実施し、多層構造重合体を含有するアクリル樹脂ラテックス（３）を得た。アクリル樹脂ラテックス（３）を用いたこと以外は、製造例１と同様の方法で、アクリル樹脂フィルムを得た。
本製造例で得られた多層構造重合体の評価、濾過後のアクリル樹脂ラテックス、及びアクリル樹脂フィルムの諸物性を表１に示す。
【００８７】
（製造例７）
濾材にステンレス鋼製のメッシュ（線径 ５０μｍ、２３５メッシュ）を取り付けた図１の構成を有する濾過装置を用いて、アクリル樹脂ラテックス（１）を流速３ｍ^３／Ｈで濾過した。この際、振幅長０ｍｍの振幅運動、回転数１２００ｒｐｍの円運動、即ち水平方向の円運動はあるが、垂直方向の振幅運動がない状態に調整して行った。
濾過開始後、濾材３上に残った凝集物の排出が不能になり、すぐに目詰まりが起こり濾過不能となった。
本製造例で得られた多層構造重合体の評価、濾過後のアクリル樹脂ラテックスを表１に示す。
【００８８】
（製造例８）
濾過処理しない以外は、製造例１と同様の方法で、アクリル樹脂フィルムを得た。
本製造例で得られた多層構造重合体の評価、アクリル樹脂ラテックスを表１に示す。
【００８９】
【表１】

【００９０】
表１から明らかなように、製造例１〜６で得られたアクリル樹脂フィルムは、透明性、表面光沢、および印刷性に優れている。
一方、製造例７では、濾材面に対して、垂直方向の振幅運動がなく、水平方向の円運動のみで濾過を行ったため、濾材上に残った凝集物の排出が不能となり、アクリル樹脂フィルムを製造することができなかった。
また、製造例８で得られたアクリル樹脂フィルムは、アクリル樹脂ラテックスの濾過処理を行わなかったために、フィッシュアイ数、印刷抜け数が多い品質に劣ったものであった。
【００９１】
【発明の効果】
本発明のアクリル樹脂フィルムの製造方法によれば、濾材上に残った凝集物等の除去作業の必要がなくなり、濾材が破損して交換する頻度を少なくすることができるため、多層構造重合体を含有するアクリル樹脂ラテックスの濾過を連続的に行うことが可能となる。
また、濾過装置に具備された水洗装置により、濾材の微細な網目構造の目の中に残留した凝集物が除去されるため、安定に濾材の目詰まりを防止することができる。
本発明のアクリル樹脂フィルムの製造方法によれば、フィルム成形性、透明性、表面光沢、および印刷性に優れ、印刷後の印刷抜け等の外観不良が少ないアクリル樹脂フィルムを製造することができる。また、そのアクリル樹脂フィルムは各種工業材料、とりわけ積層用フィルム材料としての利用価値が高く、工業的に極めて有益である。
【図面の簡単な説明】
【図１】 濾過装置を側面から示す図である。
【図２】 水洗装置を付設した濾過装置を上面から示す図である。
【符号の簡単な説明】
１ フライウエイト
２ ラテックス供給管
２ａ 吐出口
３ 濾材
４ 排出口
５ ボトムボウル
６ ラテックス排出口
７ 振動モーター
８ スプリング[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing an acrylic resin film.
[0002]
[Prior art]
Conventionally, polybutadiene latex obtained by emulsion polymerization, styrene-butadiene copolymer latex, acrylonitrile-butadiene-styrene copolymer latex, acrylic ester-containing acrylic rubber latex, etc. are rubber components for improving impact strength of hard resins. Alternatively, it is used as a binder for paper coating.
These latexes are mainly composed of particles having a particle size of 0.03 to 1 μm, but the polymer particles are distributed in the range of 1 to 200 μm due to the generation of fine aggregates during polymerization. Is also contained.
These huge polymer particles of 1 to 200 μm adversely affect the quality of the resulting emulsion latex or recovered polymer. For example, in the field of paper coating, mechanical stains (streak troubles, etc.) at the time of paper coating and a decrease in strength of the coated paper may occur, and molding plates and films may cause blisters and fish eyes.
[0003]
Generally, those containing such cullet are filtered by a solid-liquid separation method. Examples of the solid-liquid separation method include a mechanical separation method such as a gravity filtration method, a vacuum filtration method, a centrifugal separation method, and a pressure filtration method.
However, since the gravity filtration method uses gravity to perform filtration, the filtration speed is very slow and the productivity is not good.
In addition, the vacuum filtration method is widely used industrially and is a method suitable for continuous operation, but requires a vacuum source, and a latex film is easily formed on the filter medium for filtration in vacuum. May cause cullet.
Centrifugation is a method that uses the difference in specific gravity, but because the difference in specific gravity between the cullet and the polymer is small, it is difficult to separate accurately, and a separation plate is used to increase the separation function. In this case, the cullet is blocked in the flow path, and the continuous operation tends to be impossible.
Moreover, in the pressure filtration method, it is necessary to remove the cullet trapped by the filter medium by spraying washing water from the reverse direction and to discharge it outside the system, but the cullet is easily deformed when pressurized. Therefore, the filter medium is easily clogged. As a result, the filtration ability of the latex is lowered, and further, there are problems such as damage to the filter medium and liquid leakage.
[0004]
Further, as another method for removing aggregates and suspended matters contained in the latex, 1 to 100% by mass of a solvent containing chlorine is added to the copolymer, and the latex is mixed with the solvent by sufficient stirring operation. Japanese Patent Publication No. 56-5768 discloses a method in which a polymer inside is swelled and then treated with a centrifugal separator, and then the solvent is recovered and removed.
However, this method has a problem that a solvent containing chlorine is required and the solvent must be recovered and removed.
[0005]
On the other hand, Japanese Patent Publication No. 46-32058 and Japanese Patent Publication No. 3-65820 propose a method of filtering using diatomaceous earth.
However, in these methods, a part of the latex is taken into the diatomaceous earth layer by filtration, and this diatomaceous earth remains after filtration, and these have no utility value and become industrial waste. In addition, the above method has a problem in product yield.
[0006]
JP-A-9-263614 discloses that the number of foreign matters having a diameter of 80 μm or more is 1 m. ² An acrylic resin film having good printability of 1 or less per sheet and a method for producing the same are disclosed.
[0007]
[Problems to be solved by the invention]
However, there is no specific description about the filtration device used for the filtration treatment of the acrylic polymer latex, which is the method for producing the film raw material described in the above publication, or the filtration conditions. For example, the emulsified latex may be a flat plastic mesh or the like. When filtration is performed with the filtration device, the clogging occurs in a short time, and the filterability is deteriorated.
On the other hand, a polymer latex filtration device capable of efficiently removing aggregates deposited on a filter medium is described in JP-A-9-194529. However, the publication discloses a method of using a latex filtration device for the purpose of obtaining a film having excellent printability, or specifying a cause of printing loss occurring in a printing film, and a raw material polymer for suppressing this No mention is made of how to improve the latex.
[0008]
Japanese Patent Application Laid-Open No. 11-228710 describes an acrylic resin film having a height of 5 μm or more and no irregularities on the film surface. In this publication, as a method for obtaining an acrylic resin film having a height of 5 μm or more and having no irregularities, it is mentioned that the acrylic resin latex is filtered with a filter having an opening of 50 μm. Is not described at all, and there is no suggestion regarding a method for producing an acrylic resin for film raw material, which removes foreign matters in latex by industrial continuous filtration. In addition, a method of melt extrusion by providing a filter of 25 to 50 μm in an extruder is described. However, when an acrylic resin film is continuously produced by this method, the filter is clogged, so that the acrylic resin stays in the fish. There has been a problem that heat-degraded materials that cause eyes are generated.
[0009]
In addition, as a method of smoothing the film surface, when forming an acrylic resin into a film using a melt extrusion method such as T-die method or inflation or a calendering method, the smooth surface of the mirror roll is transferred. It is mentioned that the unevenness is eliminated or the unevenness on both sides of the film is eliminated by sandwiching it between two mirror rolls. However, when the film is thinned by the method of sandwiching between mirror rolls, the rolls are in contact with each other. However, since there are problems such as scratches on the roll, it has been difficult to produce an acrylic resin film that is a thin film and has no irregularities.
[0010]
[Means for Solving the Problems]
The present inventors specify that the cause of printing omission is a micro cullet having a diameter of several tens of μm present in the acrylic resin latex, and the filtration conditions and the filtration treatment when the treatment is performed using a specific filtration device. As a result of intensive studies on the relationship between the properties and the printability of an acrylic resin film containing the obtained polymer as a main component, the acrylic resin latex is filtered so that the filter medium moves horizontally and vertically with respect to the filter medium surface. It can be filtered without clogging by filtering with an apparatus, and the polymer obtained by coagulating the latex is formed into a film shape and has less fish eyes and excellent printability. did.
[0011]
That is, the method for producing an acrylic resin film of the present invention uses a filtration device in which a horizontally installed filter medium performs horizontal circular movement and vertical amplitude movement with respect to the surface of the filter medium, Acrylic resin latex whose flow rate is adjusted by a flow rate control valve or a flow rate control device is supplied from the discharge port of the latex supply pipe to substantially the center of the filter medium, filtered, A method for producing an acrylic resin film in which an acrylic resin obtained by coagulating the acrylic resin latex after removing aggregates contained in the acrylic resin latex is formed into a film,
The filtration device is equipped with a water washing device, and water at a pressure of 0.01 to 2.0 MPa blows out from the water washing device to the surface of the filter material on the side of filtering the acrylic resin latex, thereby washing the surface of the filter material. It is characterized by.
In addition, the above-mentioned filter medium undergoes circular motion and amplitude motion, so that the aggregate remaining on the filter medium is reduced to 50 m / s. ² It is preferable to give the above acceleration.
Moreover, it is preferable that the said filtration apparatus has a circular filter medium whose diameter is X, and the amplitude length of the amplitude motion by a filter medium is X / 60-X / 200.
Moreover, it is preferable that the said filter medium is formed from the fiber made from stainless steel or polyester with a wire diameter of 10-70 micrometers.
Moreover, it is preferable that the mesh size of the filter medium is 100 to 600 mesh.
In the method for producing an acrylic resin film using a multilayer structure polymer having the innermost polymer (A), the crosslinked elastic polymer (B) layer, and the outermost polymer (C) layer as basic structures, As a constituent of the combination (A), an alkyl acrylate having an alkyl group having 1 to 8 carbon atoms and / or an alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms and a graft crossing agent are contained, and a crosslinked elastic polymer (B ) As a constituent component of the layer, an alkyl acrylate having an alkyl group having 1 to 8 carbon atoms and a graft crossing agent are contained. As a constituent component of the outermost polymer (C) layer, an alkyl group having 1 to 4 carbon atoms is contained. An alkyl acrylate having an alkyl group having 1 to 8 carbon atoms between the crosslinked elastic polymer (B) layer and the outermost polymer (C) layer; An alkyl methacrylate having an alkyl group of 1 to 4 and a graft crossing agent, and the amount of the alkyl acrylate component monotonously decreases from the crosslinked elastic polymer (B) layer toward the outermost polymer (C) layer; It is preferable to have at least one intermediate polymer (D) layer.
In addition, a single component containing a graft crossing agent, which is a constituent component of the innermost polymer (A), is an alkyl acrylate having an alkyl group having 1 to 8 carbon atoms and / or an alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms. An emulsion prepared by mixing the monomer mixture with water and a surfactant is supplied to the reaction vessel and polymerized, and then the crosslinked elastic polymer (B) layer, intermediate polymer (D) layer, outermost polymer (C It is preferable to polymerize the multilayer structure polymer by sequentially supplying the monomer or monomer mixture constituting the layer to the reaction vessel.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The method for producing an acrylic resin film of the present invention produces an acrylic resin film excellent in printability by removing aggregates, suspended matters and the like contained in the acrylic resin latex by a filtration device and filtration conditions described later. be able to. Hereinafter, the multilayer structure polymer, acrylic resin latex, and acrylic resin film obtained by the production method of the present invention will be described.
[0013]
Preferable examples of the acrylic resin film obtained by the production method of the present invention include a film in which a polymer containing alkyl acrylate and / or alkyl methacrylate as a constituent component is formed.
Moreover, as a preferable specific example of the said polymer, the alkyl acrylate which has a C1-C8 alkyl group and / or the alkyl methacrylate which has a C1-C4 alkyl group from the inside, and a graft crossing agent are contained. An innermost polymer (A), an alkyl acrylate having an alkyl group having 1 to 8 carbon atoms, and a cross-linked elastic polymer (B) layer containing a graft crossing agent, an alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms And an outermost polymer (C) layer containing a C 1 -C 8 alkyl group between the crosslinked elastic polymer (B) layer and the outermost polymer (C) layer. Crosslink elastic polymerization containing an alkyl acrylate, an alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms, and a graft crossing agent and having an alkyl acrylate component amount (B) is a multi-layer polymer which at least one layer having an intermediate polymer (D) layer monotonically decreases towards the outermost polymer layer (C) from the layer.
[0014]
Hereinafter, the configuration of the multilayer structure polymer will be described.
The innermost polymer (A) comprises at least an alkyl acrylate having an alkyl group having 1 to 8 carbon atoms and / or an alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms (A1) and a graft crossing agent (A2). A polymer containing another monomer (A3) having a copolymerizable double bond and a polyfunctional monomer (A4), if necessary, and comprising a central portion of the multilayer structure Configure.
[0015]
The alkyl acrylate having an alkyl group having 1 to 8 carbon atoms may be linear or branched, and specific examples thereof include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, Examples thereof include n-octyl acrylate. These can be used individually or in mixture of 2 or more types.
[0016]
Further, the alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms may be either linear or branched, and specific examples thereof include methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate and the like. . These can be used individually or in mixture of 2 or more types.
[0017]
The alkyl acrylate having an alkyl group having 1 to 8 carbon atoms and / or the alkyl methacrylate (A1) having an alkyl group having 1 to 4 carbon atoms is 100 parts by mass in total of components (A1), (A3) and (A4). On the other hand, it is preferable to use within the range of 80-100 mass parts.
The component (A1) of the type used in the innermost polymer (A) is most preferably used uniformly in all subsequent multi-stage layers ((B), (C), (D)). However, in each of all the multistage layers, two or more kinds of alkyl (meth) acrylates may be mixed, or another kind of acrylate may be used. “(Meth) acrylate” means an alkyl acrylate having an alkyl group having 1 to 8 carbon atoms and / or an alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms.
[0018]
Examples of the graft crossing agent (A2) constituting the innermost polymer (A) include allyl, methallyl or crotyl ester of copolymerizable α, β-unsaturated carboxylic acid or dicarboxylic acid. Particularly preferred are acrylic esters of acrylic acid, methacrylic acid, maleic acid or fumaric acid. Among these, allyl methacrylate has an excellent effect.
In addition to the above, triallyl cyanurate, triallyl isocyanurate and the like are also effective.
In the graft crossing agent (A2), the conjugated unsaturated bond of the ester reacts much faster than the allyl group, methallyl group, or crotyl group, and is chemically bonded. During this time, most of the allyl group, methallyl group, or crotyl group works effectively during the polymerization of the next layer polymer to provide a graft bond between adjacent two layers.
[0019]
The amount of the graft crossing agent (A2) used is extremely important, and is preferably from 0.1 to 5 parts by weight, based on 100 parts by weight of the total amount of the components (A1), (A3) and (A4), and is preferably 0.5 to 2 parts by mass is more preferable. When the amount of the grafting agent used is less than 0.1 parts by mass, an effective amount of graft bonds formed in the innermost polymer (A) cannot be obtained. The amount of reaction with the cross-linked elastic polymer (B) polymerized to the eye increases, and the elasticity of the double-layer cross-linked rubber elastic body having a double-layer elastic body structure is lowered.
[0020]
The other monomer (A3) having a copolymerizable double bond may be used as necessary. Specific examples thereof include acrylate monomers such as higher alkyl acrylate, lower alkoxy acrylate and cyanoethyl acrylate having an alkyl group having 9 or more carbon atoms, acrylamide, acrylic acid, methacrylic acid, styrene, alkyl-substituted styrene, acrylonitrile, methacrylo A nitrile etc. are mentioned.
The amount of the other monomer (A3) having a copolymerizable double bond is in the range of 0 to 20 parts by mass with respect to a total of 100 parts by mass of the components (A1), (A3) and (A4). It is preferable to use within.
[0021]
Specific examples of the polyfunctional monomer (A4) include alkylene glycol dimethacrylates such as ethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, and propylene glycol dimethacrylate. It is preferable to use it. Further, polyvinyl benzene such as divinyl benzene and trivinyl benzene can also be used.
However, even when the polyfunctional monomer (A4) does not act at all, as long as the graft crossing agent (A2) is present, a stable multilayer structure polymer is obtained, so that it can be used as necessary. For example, when the hot strength or the like is strictly required, it may be arbitrarily used depending on the purpose of addition.
It is preferable that the usage-amount of a polyfunctional monomer (A4) is used within the range of 0-10 mass parts with respect to a total of 100 mass parts of component (A1), (A3) and (A4).
[0022]
The innermost polymer (A) having the above-described configuration is preferably contained in an amount of 5 to 35% by mass, more preferably 5 to 15% by mass in the multilayer structure polymer. Further, the content is preferably smaller than the content of the crosslinked elastic polymer (B) layer described later.
[0023]
The cross-linked elastic polymer (B) layer is a main component that imparts rubber elasticity to the multilayer polymer, and includes an alkyl acrylate (B1) having an alkyl group having 1 to 8 carbon atoms and a graft crossing agent (B2). It is a crosslinked elastic polymer containing at least another monomer (B3) having a copolymerizable double bond and a polyfunctional monomer (B4) as required.
Preferable specific examples of the components (B1) to (B4) are the same as those described for the components (A1) to (A4) constituting the innermost polymer (A).
[0024]
As for the usage-amount of the said alkyl acrylate (B1) which has a C1-C8 alkyl group, 80-100 mass parts is preferable.
Moreover, the usage-amount of the said graft crossing agent (B2) has preferable 0.1-5 mass parts.
The amount of the other monomer (B3) having a copolymerizable double bond is preferably 0 to 20 parts by mass.
Moreover, as for the usage-amount of the said polyfunctional monomer (B4), 0-10 mass parts is preferable. In addition, the range of these usage-amounts is based on a total of 100 mass parts of component (B1), (B3), and (B4).
[0025]
The Tg of the crosslinked elastic polymer (B) alone is preferably 0 ° C. or lower, and more preferably −30 ° C. or lower. It is because there exists a tendency which shows the outstanding elasticity as Tg is 0 degrees C or less.
Moreover, 10-45 mass% is preferable, and, as for content of the crosslinked elastic polymer (B) in a multilayer structure polymer, it is more preferable than content of an innermost polymer (A).
[0026]
The outermost polymer (C) layer is a component involved in the moldability, mechanical properties, etc. of the multilayer structure polymer, and an alkyl methacrylate (C1) having an alkyl group having 1 to 4 carbon atoms and, if necessary, And the other monomer (C3) having a copolymerizable double bond used as a constituent component to constitute the outermost layer of the multilayer structure polymer.
[0027]
Preferred specific examples of the alkyl methacrylate (C1) having an alkyl group having 1 to 4 carbon atoms and the other monomer (C3) having a copolymerizable double bond are the components of the innermost polymer (A). The same thing as the alkyl methacrylate which has a C1-C4 alkyl group and the other monomer (A3) which has a copolymerizable double bond is applied.
The amount of alkyl methacrylate (C1) having an alkyl group having 1 to 4 carbon atoms is preferably 51 to 100 parts by mass.
The amount of the other monomer (C3) having a copolymerizable double bond is preferably 0 to 49 parts by mass. The range of these usage-amounts is based on a total of 100 mass parts of a component (C1) and a component (C3).
[0028]
The Tg of the outermost polymer (C) alone is preferably 60 ° C. or higher, and more preferably 80 ° C. or higher.
Moreover, 10-80 mass% is preferable, and, as for content of the outermost layer polymer (C) in a multilayer structure polymer, More preferably, it is 40-60 mass%.
[0029]
The multilayer structure polymer applied to the production of the acrylic resin film of the present invention has the above innermost layer polymer (A), crosslinked elastic polymer (B) layer, and outermost layer polymer (C) layer as a basic structure. Furthermore, it is preferable to provide at least one intermediate polymer (D) layer between the crosslinked elastic polymer (B) layer and the outermost polymer (C) layer.
The intermediate polymer (D) layer comprises an alkyl acrylate having an alkyl group having 1 to 8 carbon atoms, an alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms (D1), a graft crossing agent (D2), and Accordingly, the other monomer (D3) having a copolymerizable double bond and the polyfunctional monomer (D4) are used as components of the polymer, and the amount of the alkyl acrylate component in the component (D1) However, it decreases monotonously from the crosslinked elastic polymer (B) layer toward the outermost polymer (C) layer. Here, monotonically decreasing means that the intermediate polymer (D) layer has a composition at one point between the crosslinked elastic polymer (B) layer and the outermost polymer (C) layer, the crosslinked elastic polymer (B). It means that the composition is continuously approached from the layer to the outermost polymer (C) layer and that the composition is stepwise approached, and in particular, a product having one intermediate composition may be sufficient in terms of productivity.
[0030]
Preferable specific examples of the components (D1) to (D4) are the same as those described for the components (A1) to (A4) of the innermost polymer (A). In particular, the graft crossing agent (D2) used for the intermediate polymer (D) layer is a component necessary for tightly bonding the polymer layers and obtaining excellent properties.
Moreover, as for the usage-amount of the alkyl acrylate which has a C1-C8 alkyl group, and the alkyl methacrylate (D1) which has a C1-C4 alkyl group, 10-90 mass parts is preferable.
Moreover, the usage-amount of a graft crossing agent (D2) has preferable 0.1-5 mass parts.
The amount of the other monomer (D3) having a copolymerizable double bond is preferably 0 to 20 parts by mass.
Moreover, as for the usage-amount of the said polyfunctional monomer (D4), 0-10 mass parts is preferable. The range of these usage-amounts is based on 100 mass parts of components (D1)-(D4) in total.
[0031]
The intermediate polymer (D) layer having the above-described structure is preferably contained in the multilayer structure polymer in an amount of 5 to 35% by mass. If the content of the intermediate polymer (D) layer is 5% by mass or more and 35% by mass or less, an acrylic resin film having excellent flexibility and workability can be obtained.
[0032]
The average particle size of the multilayer structure polymer composed of the above-described constituent elements is preferably 0.08 to 0.2 μm in consideration of the mechanical properties and transparency of the acrylic resin film mainly composed of the polymer. .
In addition, the film composition containing the multilayered polymer as a main component preferably has a heat distortion temperature (measured based on ASTM D648) of 70 ° C. or higher, more preferably 80 ° C. or higher. When manufacturing the laminated body which has an acrylic resin film on the surface, when a heat deformation temperature is less than 70 degreeC, it will become easy to generate | occur | produce surface roughness after a heating. Further, when the heat distortion temperature is 80 ° C. or higher, it is possible to suppress a deterioration in design due to glossy return of the embossed surface when the laminated body whose surface is roughened by embossing or the like is heat processed.
[0033]
Hereinafter, a method for measuring the heat distortion temperature based on ASTM D648 will be described.
A 127 × 12.7 × (3.18 to 12.7) mm test piece is placed horizontally on a metal support having a contact end with a radius of 3.175 mm or more and placed in a liquid bath at room temperature. 4.64 kg / cm ² Apply a load for 5 minutes perpendicularly to the center so that ± 2.5% fiber stress acts, record 0 point, increase the liquid temperature at 2 ± 0.2 ° C / min, and bend 0.254mm At a temperature of 4.64 kg / cm ² The deflection temperature at ± 2.5% is the heat distortion temperature.
[0034]
Such a multilayered structure polymer is excellent in the weather resistance, transparency and stress whitening resistance of an acrylic resin film produced using this as a raw material, and therefore is suitably used for producing an acrylic resin film.
[0035]
The thickness of the acrylic resin film produced using the multilayer polymer as a raw material is not particularly limited, but is preferably 10 to 500 μm, more preferably 15 to 200 μm, and still more preferably 40 to 200 μm. It is. When it is 10 to 500 μm, appropriate rigidity, laminating property, secondary workability and the like are improved.
[0036]
Next, the filtration device used in the present invention will be described with reference to the drawings.
FIG. 1 is a schematic view of a filtration device.
The filtration device is based on a circular structure, and includes a device body provided with a filter medium 3 and a bottom bowl 5, a vibration motor 7 provided below the device body, and a flyweight 1 provided below the vibration motor 7. It is roughly composed of
Further, a discharge port is provided in a part of the upper outer periphery of the filter medium 3, and a latex discharge port 6 is provided in a part of the upper outer periphery of the bottom bowl 5. Further, the latex supply pipe 2 is provided above the filter medium 3 so that the discharge port 2 a is located at the center of the filter medium 3. The apparatus main body is attached by a spring 8.
[0037]
Acrylic resin latex before filtration is adjusted to an appropriate flow rate by a control valve and a flow rate control device (not shown), supplied from the discharge port 2a at the end of the latex supply pipe 2 to the approximate center of the filter medium 3, and filtered. The The acrylic resin latex that has passed through the filter medium 3 is received by the bottom bowl 5 and discharged from the latex discharge port 6 to the outside of the filtration device and collected. At this time, by appropriately adjusting the flyweight 1, the filter medium 3 performs horizontal circular movement and vertical amplitude movement with respect to the surface of the filter medium 3.
On the other hand, the condensate, suspended matter, etc. remaining on the filter medium 3 move spirally on the filter medium 3 by circular motion and amplitude motion by the filter medium 3 described later, and are continuously discharged from the discharge port 4.
[0038]
The filtration device used in the present invention is one in which the filter medium 3 performs a horizontal circular motion and a vertical amplitude motion with respect to the surface of the filter medium. 50 m / s on the remaining aggregate ² The above acceleration can be given. The acceleration applied to the aggregate remaining on the filter medium 3 is 50 m / s. ² By setting it as the above, an aggregate can be discharged | emitted smoothly. Conversely, the acceleration is 50 m / s ² If the ratio is less than 1, the discharge of aggregates remaining on the filter medium 3 becomes difficult, and clogging tends to occur.
Further, the acceleration applied to the aggregate remaining on the filter medium 3 is given by the following calculation formula.
[0039]
[Expression 1]

K: Maximum acceleration (m / s ² ), R; screen amplitude (m), ω; angular velocity (rad / sec)
N: Motor rotation speed (rpm)
For example, when the screen amplitude is 3.5 mm and the motor speed is 1800 rpm
K = 3.5 × 10 ^-3 × (2π × 1800/60) ² = 124m / s ² It becomes.
[0040]
Moreover, it is desirable that the filtration device has a circular filter medium 3 having a diameter X, and the amplitude length in the direction perpendicular to the surface of the filter medium 3 is X / 60 to X / 200. When the amplitude length in the vertical direction is less than X / 200, the aggregate remaining on the filter medium 3 is difficult to be discharged, and clogging tends to occur. On the other hand, if the amplitude is larger than X / 60, the load on the filter medium 3 is large and the durability tends to be short.
[0041]
The filter medium 3 is preferably formed of stainless steel or polyester fibers, and stainless steel is particularly preferable. This is because, in the above-described washing of the filter medium 3 by the water washing apparatus, the water pressure can be relatively increased with the stainless steel material, and the effect of preventing clogging can be improved.
Moreover, it is preferable that the wire diameter of the filter medium 3 is 10-70 micrometers. When the wire diameter is smaller than 10 μm, the filter medium 3 is weak and easily breaks. On the other hand, when the thickness is larger than 70 μm, the degree of opening becomes small and the filtration area becomes narrow, so that the filtration efficiency tends to deteriorate.
[0042]
The filter medium 3 preferably has a mesh size of 100 to 600 mesh, more preferably 150 to 400 mesh. When the size of the eyes is larger than 100 mesh, solids such as aggregates and suspended solids contained in the emulsified latex are likely to be mixed in the filtered acrylic resin latex, so the polymer obtained from this acrylic resin latex There is a tendency that bumps and fish eyes are likely to occur in a resin molded plate or film using the. On the other hand, when the size of the eyes exceeds 600 mesh, the filter medium 3 tends to be clogged.
[0043]
Further, as shown in FIG. 2, the filtration device used in the present invention is provided with a water washing device 10 capable of washing the surface of the filter medium 3 with a water flow. The Moreover, since this filter apparatus has the same basic structure as the above-described filter apparatus, only the water washing apparatus will be described.
As an example of the water washing device, a nozzle that sprays water for washing the filter medium 3 (wash water) against the filter medium 3 16 And this nozzle 16 A circular water conduit 17 provided with a joint, a joint 18 for fixing the washing device, a joint 19 connecting the circular water conduit 17 and the joint 18, and a guide for introducing water from the outside of the washing device. A water washing apparatus roughly constituted by the water pipe 20 can be used.
In the water washing apparatus, water introduced into the water conduit 20 from the outside of the apparatus passes through a conduit (not shown) provided in the joint 18 and passes through a conduit (not shown) provided in the connecting portion 19. Further, the nozzle is supplied into the circular water conduit 17. 16 Is sprayed onto the filter medium 3.
[0044]
Above nozzle 16 The water jetted from the filter medium 3 is at a pressure of 0.01 to 2.0 MPa. On the side to filter the acrylic resin latex On the other hand, foreign matters in the details of the filter medium 3 are removed, and clogging can be stably prevented. nozzle 16 When the pressure of the water sprayed from is less than 0.01 MPa, the pressure is low and the effect of preventing clogging is small. On the other hand, if it exceeds 2.0 MPa, the durability of the filter medium 3 may be impaired.
[0045]
By performing filtration using such a filtration device, it is not necessary to remove aggregates and the like remaining on the filter medium 3, and the frequency with which the filter medium 3 is damaged and replaced can be reduced. It becomes possible to continuously filter the acrylic resin latex containing the polymer.
Moreover, since the agglomerate remaining in the fine mesh structure of the filter medium 3 is removed by the water washing apparatus, the filter medium 3 can be prevented from being clogged stably.
In addition, if the filter medium 3 is moved in a circular motion and an amplitude while the water is sprayed from the water washing device to the filter medium 3, the water can be sprayed evenly over the entire surface of the filter medium 3, thereby improving the cleaning effect.
[0046]
Hereinafter, the manufacturing method of the acrylic resin film of this invention is demonstrated.
In the method for producing an acrylic resin film of the present invention, first, an acrylic resin latex containing a multilayer structure polymer is produced, and this is filtered using the filtration device described above, and then the filtrate is coagulated to obtain a multilayer structure polymer. It collect | recovers and shape | molds this in a film form.
[0047]
Examples of the method for producing an acrylic resin latex containing a multilayer structure polymer include, for example, an alkyl acrylate having an alkyl group having 1 to 8 carbon atoms and giving an innermost polymer (A) serving as a central portion of the multilayer structure polymer, and / or Alternatively, a monomer mixture containing at least an alkyl methacrylate (A1) having an alkyl group having 1 to 4 carbon atoms and a graft crossing agent (A2) is supplied and polymerized, and then the crosslinked elastic polymer (B) layer, intermediate weight A method of obtaining an acrylic resin latex by supplying a monomer or a monomer mixture that gives a combined (D) layer and an outermost polymer (C) layer to a reaction vessel in order and polymerizing a multilayer structure polymer. There is.
Moreover, the alkyl acrylate which has a C1-C8 alkyl group and / or the alkyl methacrylate which has a C1-C4 alkyl group which give the innermost polymer (A) used as the center part of a multilayer structure polymer (A1) And a monomer mixture containing at least the graft crossing agent (A2) with water and a surfactant to prepare an emulsion, supply the emulsion to a reaction vessel, polymerize, and then crosslink an elastic polymer. (B) A monomer or a monomer mixture that provides an intermediate polymer (D) layer and an outermost polymer (C) layer are sequentially supplied to the reaction vessel, and the multilayer structure polymer is polymerized. There is a method of obtaining an acrylic resin latex.
[0048]
As a method for preparing the above emulsion, water and a monomer mixture are charged into a mixing device such as a stirrer equipped with a stirring blade, a homogenizer, a homomixer, and other forced emulsifiers and a membrane emulsifier, and then a surface activity. A method of charging an agent, a method of charging a monomer mixture after charging water and a surfactant into a mixing device, a method of charging water after charging a monomer mixture and a surfactant into a mixing device, etc. Is mentioned. Among these, the method of charging a surfactant after charging a monomer mixture in water, and the method of charging a monomer mixture after charging a surfactant in water include the multilayer structure polymer described above. It is suitable as a method for obtaining
[0049]
The mass ratio of the monomer mixture to water when preparing the emulsion is preferably 10 to 500 parts of water with respect to 100 parts of the monomer mixture, more preferably 100 parts of water with respect to 100 parts of the monomer mixture. ~ 300 parts.
[0050]
As the surfactant used for the preparation of the emulsion, anionic, cationic and nonionic surfactants can be used, and anionic surfactants are particularly preferable. Examples of anionic surfactants include rosin acid soap, potassium oleate, sodium stearate, sodium myristate, sodium N-lauroylsarcosate, alkenyl succinate dipotassium salt, sulfate ester such as sodium lauryl sulfate, etc. Examples thereof include salts, sulfonic acid salts such as sodium dioctylsulfosuccinate, sodium dodecylbenzenesulfonate, sodium alkyldiphenyl ether disulfonate, and phosphoric acid ester salts such as sodium polyoxyethylene alkylphenyl ether phosphate.
[0051]
In addition, the emulsion can be used in either a W / O type or an O / W type dispersion structure. In particular, the emulsion is an O / W type in which oil droplets of a monomer mixture are dispersed in water. The diameter of the oil droplet is preferably 100 μm or less, more preferably 50 μm or less, and still more preferably 15 μm or less. If the diameter of the oil droplets in the dispersed phase exceeds 100 μm, the number of huge polymer particles distributed in the range of 1 to 200 μm contained in the obtained acrylic resin latex tends to increase.
[0052]
In order to produce an acrylic resin latex containing a multilayered polymer using the emulsion prepared in this way, for example, after introducing a polymerization initiator into a reaction vessel and raising the temperature to the polymerization temperature, An emulsion for forming the innermost polymer (A) is supplied for polymerization.
Next, a monomer or a monomer mixture that provides a cross-linked elastic polymer (B) layer, an intermediate polymer (D) layer, and an outermost polymer (C) layer containing a polymerization initiator such as a peroxide is sequentially added. The acrylic resin latex containing the multilayer structure polymer can be produced by supplying it to the reaction vessel.
[0053]
As the polymerization initiator, known ones can be used, and specific examples thereof include peroxides, azo initiators, or redox initiators combined with an oxidizing agent / reducing agent. Of these, redox initiators are preferable, and sulfoxylate initiators in which ferrous sulfate, ethylenediaminetetraacetic acid disodium salt, longalite, and hydroperoxide are combined are particularly preferable.
[0054]
As explained above, after supplying the above emulsion for forming the innermost polymer (A) to the reaction vessel and polymerizing, the crosslinked elastic polymer (B), the intermediate polymer (D) layer, the outermost polymer ( C) In the method in which the monomer or monomer mixture constituting the layer is sequentially supplied to the reaction vessel to polymerize the multilayer structure polymer, it is distributed in the range of 1 to 200 μm existing in the acrylic resin latex. Since huge polymer particles can be reduced, an acrylic resin film excellent in printability can be produced.
[0055]
The acrylic resin latex containing the multilayer structure polymer obtained in this way is removed of aggregates and suspended matters contained therein by the filtration device described above. Hereinafter, the method for filtering the acrylic resin latex will be described with reference to FIG.
For example, an acrylic resin latex containing a multilayer structure polymer is sent to the latex supply pipe 2 by a liquid feed pump (not shown) or the like and supplied onto the filter medium 3 from the discharge port 2a. At this time, the flow rate of the acrylic resin latex can be appropriately adjusted by a flow rate control device or a control valve (not shown). And the filtrate which permeate | transmitted the filter medium 3, ie, the acrylic resin latex from which the aggregate and the floating matter were removed, can be collect | recovered by the bottom bowl 5. FIG.
[0056]
As filtration conditions, flow rate 0.1-20m ^Three / H, and the acceleration that gives circular motion and amplitude motion by the filter medium 3 to the acrylic resin latex is 50 m / s. ² It is preferable to set so as to be above. Further, the preferred range of the amplitude length in the vertical direction relative to the surface of the filter medium 3 is X / 60 to X / 200 (X represents the diameter of the filter medium 3), and the preferred range of the rotational speed of the horizontal circular motion is 60 × (50 / (X / 60)) ^1/2 / 2πrpm or more.
By performing filtration in this way, clogging in a short time can be prevented, and huge polymers that adversely affect the quality of the acrylic resin film can be removed without impairing filterability. An acrylic resin film excellent in printability can be produced.
[0057]
The method for recovering the multilayer structure polymer from the acrylic resin latex subjected to the filtration treatment as described above is not particularly limited, and examples thereof include salting out, acid precipitation coagulation, spray drying, and freeze drying. By the method, the multilayer polymer is recovered in powder form.
[0058]
The method for forming the acrylic resin film from the multilayer structure polymer is not particularly limited, and examples thereof include known solution casting methods, melt extrusion methods such as a T-die method, and an inflation method. Among these, the T-die method is most preferable from the viewpoint of economy.
[0059]
A general compounding agent can be added to the acrylic resin film produced as described above, if necessary. Examples of the compounding agents include stabilizers, lubricants, processing aids, plasticizers, impact aids, foaming agents, fillers, antibacterial agents, antifungal agents, foaming agents, mold release agents, antistatic agents, and coloring. Agents, matting agents, ultraviolet absorbers and the like. Particularly in terms of protecting the substrate, it is preferable to add an ultraviolet absorber in order to impart weather resistance.
[0060]
When an ultraviolet absorber is added, the molecular weight is preferably 300 or more, particularly preferably 400 or more. When an ultraviolet absorber having a molecular weight of less than 300 is used, it may volatilize on a transfer roll or the like when producing a film, thereby causing roll contamination.
The type of the ultraviolet absorber is not particularly limited, but a benzotriazole type having a molecular weight of 400 or more or a triazine type having a molecular weight of 400 or more can be particularly preferably used. As a specific example of the former, the trade name Tinuvin 234 (Ciba Geigy Co., Ltd.) can be used. Product name) ADK STAB LA-31 (manufactured by Asahi Denka Kogyo Co., Ltd.), and specific examples of the latter include trade name Tinuvin 1577 (manufactured by Ciba Geigy Corp.).
[0061]
As a method of adding the compounding agent, there are a method of supplying the film forming machine for forming a film using the multilayer structure polymer together with the multilayer structure polymer, and a mixture in which the compounding agent is previously added to the multilayer structure polymer. There are methods of kneading and mixing with various kneaders. Examples of the kneader used in the latter method include ordinary single screw extruders, twin screw extruders, Banbury mixers, roll kneaders, and the like.
[0062]
According to the production method of the present invention, it is possible to produce an acrylic resin film with less fish eyes. Even when a gravure printing is applied, there is little printing loss, and a high level of printability that is never obtained with an acrylic resin film using a conventionally known multilayer structure polymer as a raw material.
Generally, the number of missing prints when gravure printing is performed is 20 / m ² In the following cases, it can be used for various industrial applications from the viewpoint of design properties. However, the number of print omissions is 1 / m in the case of vehicle interior skin applications that require a particularly high level of design properties. ² The printed film is required to be the following. According to the manufacturing method of the present invention, the number of print omissions is 1 / m even under conditions such as full surface printing (solid printing) where printing omissions are likely to occur. ² Since the following acrylic resin films are obtained, a high level of designability can be imparted and the industrial utility value is extremely high.
[0063]
The acrylic resin film obtained by the production method of the present invention can be used after printing by an appropriate printing method as necessary in order to impart designability to various substrates. In this case, it is preferable to use an acrylic resin film that has been subjected to one-side printing treatment, and backside printing in which the printing surface is arranged on the adhesive surface with the base resin is preferable from the viewpoint of protecting the printing surface and imparting a high-class feeling. .
Further, when the color tone of the base material is utilized and used as an alternative to transparent coating, it can be used as it is transparent. In particular, the acrylic resin film is superior in terms of transparency, depth and luxury in comparison with the polyvinyl chloride film and the polyester film for applications in which the color tone of the base material is utilized.
[0064]
Moreover, the acrylic resin film obtained by the manufacturing method of this invention can also be laminated | stacked on a base material.
Examples of the base material to be laminated include various resin molded products, woodwork products, and metal molded products. Among the resin molded products, as the thermoplastic resin molded product that can be melt bonded to the acrylic resin film of the present invention, ABS resin, AS resin, polystyrene resin, polycarbonate resin, vinyl chloride resin, acrylic resin, polyester resin, Alternatively, a resin containing these as a main component can be mentioned, but an ABS resin, an AS resin, a polycarbonate resin, a vinyl chloride resin, or a resin containing these resins as a main component is preferable in terms of adhesiveness. However, it is possible to adhere an acrylic resin film and a base material by using an adhesive layer even with a base resin that is not thermally fused, such as polyolefin resin.
[0065]
In the production of a laminate having the acrylic resin film of the present invention on the surface, when forming into a two-dimensional laminate, a known method such as thermal lamination can be used for a base material that can be heat-sealed. . Moreover, it is possible to bond to the base material which is not heat-bonded through an adhesive.
[0066]
When molding into a three-dimensional laminate, insert molding method in which an acrylic resin film that has been processed in advance is inserted into an injection mold, or in-mold molding that performs injection molding after vacuum molding in the mold. A known molding method such as a method can be used. In the in-mold molding method, after the film is heated, vacuum molding is performed in a mold having a vacuuming function. This method is preferable from the viewpoints of workability and economy because the film can be molded and injection molded in one step.
The heating temperature is preferably not less than the temperature at which the acrylic resin film is softened, usually 70 ° C. or more. This depends on the thermal properties of the acrylic resin film or the shape of the molded product. On the other hand, if the temperature is too high, the surface appearance deteriorates and the releasability deteriorates. Although this also depends on the thermal properties of the film or the shape of the molded product, it is usually preferably 170 ° C. or lower.
The in-mold molding method is such that after forming a three-dimensional shape by vacuum molding, acrylic laminate molding having an acrylic resin film layer on the surface layer is achieved by melting and integrating the acrylic resin film and the base resin by injection molding. Goods can be obtained.
[0067]
Moreover, the acrylic resin film obtained by the manufacturing method of this invention can give surface treatment for various functions provision as needed.
Surface treatments for imparting functions include printing processes such as silk printing and inkjet printing, metal deposition for imparting metal tone or antireflection, sputtering, wet plating treatment, surface hardening treatment for improving surface hardness, and contamination prevention. Water repellent treatment or photocatalyst layer forming treatment, anti-dust adhesion treatment, anti-static treatment for anti-electromagnetic wave cutting, anti-reflection layer formation, anti-glare treatment and the like.
[0068]
Moreover, as another use of the acrylic resin film obtained by the production method of the present invention, it is used for a polarizing film protective film used for a polarizing plate such as a liquid crystal display, or a retardation plate for viewing angle compensation and retardation compensation. There is a retardation film. In these polarizing film protective films and retardation films, it is necessary that there is no optical distortion derived from fish eye that causes optical defects simultaneously with optical uniformity and transparency, and can be obtained by the production method of the present invention. The acrylic resin film makes use of the above-mentioned optical film by utilizing a high level of low fisheye number, which has not been conventionally used.
[0069]
Further, as another industrial application field of a laminate having an acrylic resin film obtained on the surface by the production method of the present invention, a high-intensity reflective material used for a road sign, a display board, or a safety device for the purpose of visibility There is.
The types of high-brightness reflectors include capsule-type reflectors in which aluminum-deposited glass beads are embedded in the substrate, and prism-type reflectors that use a prism-processed resin sheet as a reflector. Moreover, the acrylic resin film using the multilayer structure polymer mentioned above can be suitably used as a protective film used by being laminated on the surface of the reflector.
That is, the high-brightness reflective material having the acrylic resin film obtained by the production method of the present invention on the surface is less likely to deteriorate the visibility of the high-brightness reflective material derived from fish eye. The practical use value is extremely high.
[0070]
【Example】
The present invention will be described in detail with reference to examples. still, Manufacturing In the examples, “part” represents “part by mass” and “%” represents “% by mass”. Abbreviations are as follows.
MMA is methyl methacrylate, BA is butyl acrylate, AMA is allyl methacrylate, 1.3BD is 1.3-butylene glycol dimethacrylate, tBH is t-butyl hydroperoxide, CHP is cumene hydroperoxide, nOM is n-octyl mercaptan Indicates.
Emulsifier (1): sodium hydroxide partial neutralized product of 40% mono (polyoxyethylene nonylphenyl ether) phosphoric acid and 60% di (polyoxyethylene nonylphenyl ether) phosphoric acid (trade name “phosphanol LO529”) Manufactured by Toho Chemical Co., Ltd.).
[0071]
To be described later Manufacturing Various properties of the multilayer structure polymer, the acrylic resin latex, and the acrylic resin film obtained in the examples were evaluated by the following test methods.
(1) Measurement of solid content concentration
The solid content in the acrylic resin latex was determined by drying 30 ml of acrylic resin latex in a gear oven (300 ° C.) for 30 minutes and measuring the solid content.
[0072]
(2) Measurement of average particle size
The average particle size of the multilayer structure polymer was determined by an absorbance method.
(3) Measurement of aggregate amount
The amount of aggregate in the latex was determined by filtering 100 ml of latex through a 330 mesh nylon filter and measuring the mass of the filtrate remaining on the filter medium.
[0073]
(4) Filtration status
Filtration was carried out continuously for 12 hours and judged from the operational stability.
A: The state of the filter medium is very good, unchanged from immediately after the start of filtration.
○: There are some bubbles on the filter medium, but the filterability is unchanged and good
×: Unfilterable
[0074]
(5) Number average particle size measurement of dispersed phase in emulsion
One drop of the emulsion was dropped on a glass plate, the diameter of 20 dispersed phases in the emulsion was measured with an optical microscope, and the average particle diameter was determined from the average value thereof.
[0075]
(6) Gel content of multilayer structure polymer
The weighed multilayered structure polymer was extracted under reflux in an acetone solvent, the treated solution was separated by centrifugation, the solid content was dried, mass-measured (mass after extraction), and determined by the following formula.
Gel content rate (%) = (mass before extraction (g) −mass after extraction (g)) / mass before extraction (g)
(7) Thermal deformation temperature of the film composition
The pellets of the film composition were formed into heat deformation temperature measurement specimens based on ASTM D648 by injection molding, annealed at 80 ° C. for 24 hours, and then measured according to ASTM D648 at low load (0.45 MPa).
[0076]
(8) Total light transmittance and haze of the film
Evaluation was made according to JIS K6714.
(9) Surface gloss of film
The surface gloss of the film was measured at 60 ° using a gloss meter (GM-26D type manufactured by Murakami Color Research Laboratory).
[0077]
(10) Number of fish eyes
0.1m thick film 1m ² The number of fish eyes is 1 pixel (0.4 mm x 0.5 mm) or more with a light transmittance of 75% or less with a high-speed, high-functional surface defect inspection system LSC-100 (manufactured by Mitsubishi Rayon Co., Ltd.). Measure the number of.
(11) Number of missing prints
Perform black gravure printing on the film (solid printing), 20m ² The number of missing prints in the film was visually measured and 1 m ² The number of missing prints per hit was determined.
[0078]
(Manufacture of acrylic resin latex (1) containing a multilayer structure polymer)
In a polymerization vessel equipped with a condenser, 195 parts of ion-exchanged water is charged, the temperature is raised to 70 ° C., and 0.20 part of sodium formaldehyde sulfoxylate and 0.0001 of ferrous sulfate are added to 5 parts of ion-exchanged water. And a mixture prepared by adding 0.0003 parts of EDTA were added all at once.
Next, with stirring under nitrogen, a monomer mixture consisting of 0.3 part of MMA, 4.5 parts of BA, 0.2 part of BD, 0.05 part of AMA, 0.025 part of CHP and 1.3 parts of emulsifier (1) After the mixture was dropped into the polymerization vessel over 8 minutes, the reaction was continued for 15 minutes to complete the polymerization of the innermost polymer (A-1).
Subsequently, a monomer mixture consisting of 1.5 parts of MMA, 22.5 parts of BA, 1.0 part of BD, and 0.25 part of AMA was added over 90 minutes together with 0.016 part of CHP, and then the reaction was continued for 60 minutes to obtain crosslinking elasticity. A polymer (B-1) layer was formed.
Subsequently, a mixture of 6 parts of MMA, 4 parts of BA, 0.075 part of AMA, and 0.0125 part of CHP was dropped into the polymerization vessel over 45 minutes, and then the reaction was continued for 60 minutes to form an intermediate polymer (D-1) layer. Formed.
Subsequently, a monomer mixture consisting of 55.2 parts of MMA, 4.8 parts of BA, 0.19 part of n-OM and 0.08 part of t-BH was dropped into the polymerization vessel over 140 minutes, and then the reaction was continued for 60 minutes. The outermost polymer (C-1) layer was formed to obtain an acrylic resin latex (1) containing a multilayer structure polymer.
[0079]
(Manufacture of acrylic resin latex (2) containing a multilayer structure polymer)
After charging 8.5 parts of ion-exchanged water into a vessel equipped with a stirrer, a monomer mixture comprising 0.3 part of MMA, 4.5 parts of BA, 0.2 part of BD, 0.05 part of AMA, and 0.025 part of CHP was added. The mixture was added and stirred and mixed. Thereto was added 1.3 parts of emulsifier (1) with stirring, and stirring was further continued for 20 minutes to prepare an emulsion (N-2). The average particle size of the dispersed phase in the obtained emulsion was 10 μm.
Next, 186.5 parts of ion exchange water is put into a polymerization vessel equipped with a cooler, the temperature is raised to 70 ° C., and 0.20 part of sodium formaldehyde sulfoxylate is added to 5 parts of ion exchange water. A mixture prepared by adding 0.0001 part of ferrous iron and 0.0003 part of EDTA was added all at once.
Subsequently, while stirring under nitrogen, the emulsion (N-2) was dropped into the polymerization vessel over 8 minutes, and then the reaction was continued for 15 minutes to complete the polymerization of the innermost polymer (A-2). .
Subsequently, a monomer mixture consisting of 1.5 parts of MMA, 22.5 parts of BA, 1.0 part of BD, and 0.25 part of AMA was added over 90 minutes together with 0.016 part of CHP, and then the reaction was continued for 60 minutes to obtain crosslinking elasticity. A polymer (B-2) layer was formed.
Subsequently, a mixture of 6 parts of MMA, 4 parts of BA, 0.075 part of AMA, and 0.0125 part of CHP was dropped into the polymerization vessel over 45 minutes, and then the reaction was continued for 60 minutes to form an intermediate polymer (D-2) layer. Formed.
Subsequently, a monomer mixture consisting of 55.2 parts of MMA, 4.8 parts of BA, 0.19 part of n-OM and 0.08 part of t-BH was dropped into the polymerization vessel over 140 minutes, and then the reaction was continued for 60 minutes. The outermost polymer (C-2) layer was formed to obtain an acrylic resin latex (2) containing a multilayer structure polymer.
[0080]
( Manufacturing Example 1)
Using a filtration apparatus having the configuration of FIG. 1 with a stainless steel mesh (wire diameter 50 μm, 235 mesh) attached to the filter medium, acrylic resin latex (1) is flowed for 3 hours at a flow rate of 3 m. ³ / H filtered. At this time, the acceleration given to the agglomerate remaining on the filter medium 3 is 55 m / s by the circular motion with the amplitude length of 5.0 mm and the rotational speed of 1000 rpm. ² Adjust to It was. Obtained in this production example Evaluation of multilayer polymer, various properties of acrylic resin latex after filtration The table It is shown in 1. The filter medium 3 has a diameter of 600 mm and will be described later. Production Examples 2-8 The same size filter medium 3 was also used.
Further, the multilayer structure polymer contained in the acrylic resin latex (1) obtained by filtration as described above is salted out in an aqueous solution containing 3 parts of calcium acetate, washed with water, dried, and dried to form a powdery multilayer A structural polymer was obtained. The gel content of the multilayer structure polymer was 60%.
[0081]
Next, 100 parts of the above multilayer structure polymer, 2.1 parts of ADK STAB LA-31RG (Asahi Denka Co., Ltd.), 0.1 part of ADK STAB AO-50 (Asahi Denka Co., Ltd.), ADK STAB After adding 0.3 parts of LA-57 (manufactured by Asahi Denka Co., Ltd.), the mixture was mixed using a Henschel mixer, and this mixture was heated to 230 ° C. (PCM- manufactured by Ikekai Tekko Co., Ltd.) 30) and kneaded to obtain pellets. The results of the heat distortion temperature of the obtained pellets are shown in Table 1.
The pellets produced by the above method were dried overnight at 80 ° C., and a cylinder temperature of 200 ° C. to 240 ° C. was used, using a 40 mmφ non-vent screw type extruder (L / D = 26) equipped with a 300 mm wide T-die. An acrylic resin film having a thickness of 50 μm was formed at a T die temperature of 250 ° C. and a cooling roll temperature of 70 ° C. Table 1 shows the physical properties of the obtained acrylic resin film.
[0082]
( Manufacturing Example 2)
Except for using acrylic resin latex (2) instead of acrylic resin latex (1), Manufacturing In the same manner as in Example 1, an acrylic resin film was obtained.
Book Manufacturing Obtained in the example Many Table 1 shows the evaluation of the layer structure polymer, the acrylic resin latex after filtration, and various physical properties of the acrylic resin film.
[0083]
( Manufacturing Example 3)
Using the apparatus of FIG. 1 with a polyester mesh (wire diameter: 50 μm, 235 mesh) attached to the filter medium, acrylic resin latex (1) was applied for 12 hours at a flow rate of 3 m. ³ / H filtered. At that time, the amplitude length of the filter medium 3 is 3.5 mm, the rotation speed is 1700 rpm, and the acceleration applied to the aggregate is 111 m / s. ² Except for adjusting to Manufacturing In the same manner as in Example 1, an acrylic resin film was obtained.
Book Manufacturing Obtained in the example Many Table 1 shows the evaluation of the layer structure polymer, the acrylic resin latex after filtration, and various physical properties of the acrylic resin film.
[0084]
( Manufacturing Example 4)
Using a filtration apparatus having the configuration of FIG. 1 with a polyester mesh (wire diameter 48 μm, 282 mesh) attached to the filter medium, acrylic resin latex (1) is flowed for 12 hours at a flow rate of 3 m. ³ / H filtered. At this time, the acceleration given to the aggregate remaining on the filter medium 3 is 55 m / s by the amplitude motion of the amplitude length of 3.5 mm and the circular motion of the rotation speed of 1200 rpm. ² Except adjusted to Manufacturing In the same manner as in Example 1, an acrylic resin film was obtained.
Book Manufacturing Obtained in the example Many Table 1 shows the evaluation of the layer structure polymer, the acrylic resin latex after filtration, and various physical properties of the acrylic resin film.
[0085]
( Manufacturing Example 5)
A stainless steel mesh (wire diameter 50 μm, 235 mesh) for the filter medium, and a water washing device attached to the upper part of the filter medium 2 The acrylic resin latex (1) is used for 12 hours at a flow rate of 3 m. ³ / H, and filtered periodically with water washing (water pressure 0.7 MPa of each nozzle, water washing for 10 seconds at intervals of 5 minutes). At this time, the acceleration given to the agglomerate remaining on the filter medium 3 is 55 m / s due to the amplitude motion having an amplitude length of 5.0 mm and the circular motion having a rotation speed of 1000 rpm. ² Adjust to Many Evaluation of the layer structure polymer and various physical properties of the acrylic resin latex (1) after filtration were examined. The results are shown in Table 1.
Moreover, using acrylic resin latex (1) obtained by filtration as described above, Manufacturing In the same manner as in Example 1, an acrylic resin film was obtained. Table 1 shows the physical properties of the obtained acrylic resin film.
[0086]
( Manufacturing Example 6)
In the production of the acrylic resin latex (1) containing the multilayer structure polymer, the monomer mixture used to form the outermost polymer (C-1) layer is 58.2 parts of MMA, 1.8 parts of BA, n Except for changing to -OM 0.19 part and t-BH 0.08 part, emulsion polymerization was carried out in the same manner to obtain an acrylic resin latex (3) containing a multilayer structure polymer. Except for using acrylic resin latex (3), Manufacturing In the same manner as in Example 1, an acrylic resin film was obtained.
Book Manufacturing Obtained in the example Many Table 1 shows the evaluation of the layer structure polymer, the acrylic resin latex after filtration, and various physical properties of the acrylic resin film.
[0087]
( Production Example 7 )
Acrylic resin latex (1) is flowed at a flow rate of 3 m using a filtration apparatus having the configuration of FIG. 1 in which a stainless steel mesh (wire diameter: 50 μm, 235 mesh) is attached to the filter medium. ³ / H filtered. At this time, an amplitude motion with an amplitude length of 0 mm and a circular motion with a rotation speed of 1200 rpm, that is, a horizontal circular motion, were adjusted to be in a state where there was no vertical amplitude motion.
After the start of filtration, the aggregate remaining on the filter medium 3 could not be discharged, and clogging occurred immediately and filtration became impossible.
Book Manufacturing Obtained in the example Many Table 1 shows the evaluation of the layer structure polymer and the acrylic resin latex after filtration.
[0088]
( Production Example 8 )
Other than not filtering Manufacturing In the same manner as in Example 1, an acrylic resin film was obtained.
Book Manufacturing Obtained in the example Many Table 1 shows the evaluation of the layer structure polymer and the acrylic resin latex.
[0089]
[Table 1]

[0090]
As is clear from Table 1, Manufacturing The acrylic resin films obtained in Examples 1 to 6 are excellent in transparency, surface gloss, and printability.
on the other hand, Production Example 7 In the filter media surface, there is no vertical amplitude motion, and only the circular motion in the horizontal direction is used for filtration. As a result, the aggregate remaining on the filter media cannot be discharged, and an acrylic resin film can be produced. There wasn't.
Also, Production Example 8 The acrylic resin film obtained in the above was inferior in quality with a large number of fish eyes and printing omissions because the acrylic resin latex was not filtered.
[0091]
【The invention's effect】
According to the method for producing an acrylic resin film of the present invention, it is not necessary to remove aggregates remaining on the filter medium, and the frequency of replacing the filter medium due to breakage can be reduced. It becomes possible to continuously filter the acrylic resin latex contained therein.
Moreover, since the aggregate remaining in the fine mesh structure of the filter medium is removed by the water washing apparatus provided in the filter apparatus, it is possible to stably prevent the filter medium from being clogged.
According to the method for producing an acrylic resin film of the present invention, it is possible to produce an acrylic resin film that is excellent in film moldability, transparency, surface gloss, and printability, and has few appearance defects such as print omission after printing. Moreover, the acrylic resin film has a high utility value as various industrial materials, particularly as a film material for lamination, and is extremely useful industrially.
[Brief description of the drawings]
FIG. 1 is a side view of a filtration device.
FIG. 2 is a top view of a filtration device provided with a water washing device.
[Brief description of symbols]
1 Flyweight
2 Latex supply pipe
2a Discharge port
3 Filter media
4 outlet
5 Bottom bowl
6 Latex outlet
7 Vibration motor
8 Spring

Claims (7)

An acrylic resin latex whose flow rate is adjusted by a flow rate control valve or a flow rate control device using a filtration device in which a horizontally installed filter material moves horizontally in a circular direction and in a vertical direction with respect to the surface of the filter material. Acrylic obtained by coagulating the acrylic resin latex after removing the aggregates contained in the acrylic resin latex by supplying it to the center of the filter medium from the discharge port of the latex supply pipe and filtering. A method for producing an acrylic resin film for molding a resin into a film,
The filtration device is equipped with a water washing device, and water at a pressure of 0.01 to 2.0 MPa blows out from the water washing device to the surface of the filter material on the side of filtering the acrylic resin latex, thereby washing the surface of the filter material. A method for producing an acrylic resin film. ^{2. The} method for producing an acrylic resin film according to claim 1, wherein an acceleration of 50 m / s ² or more is applied to the aggregate remaining on the filter medium by the circular movement and the amplitude movement of the filter medium.   The acrylic resin film according to claim 1 or 2, wherein the filtration device has a circular filter medium having a diameter X, and the amplitude length of the amplitude motion by the filter medium is X / 60 to X / 200. Manufacturing method.   The said filter medium is formed from the fiber made from stainless steel or polyester with a wire diameter of 10-70 micrometers, The manufacturing method of the acrylic resin film in any one of Claims 1-3 characterized by the above-mentioned.   The method for producing an acrylic resin film according to any one of claims 1 to 4, wherein the filter medium has a mesh size of 100 to 600 mesh. The acrylic resin is a multilayer structure polymer having a basic structure of an innermost polymer (A), a cross-linked elastic polymer (B) layer, and an outermost polymer (C) layer in order from the inside,
As a constituent of the innermost polymer (A), an alkyl acrylate having an alkyl group having 1 to 8 carbon atoms and / or an alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms, and a graft crossing agent are contained.
As a constituent of the crosslinked elastic polymer (B) layer, an alkyl acrylate having an alkyl group having 1 to 8 carbon atoms, and a graft crossing agent are contained,
As a constituent of the outermost polymer (C) layer, containing an alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms,
Further, between the crosslinked elastic polymer (B) layer and the outermost polymer (C) layer, an alkyl acrylate having an alkyl group having 1 to 8 carbon atoms, and an alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms, And at least one intermediate polymer (D) layer containing a graft crossing agent and in which the amount of the alkyl acrylate component monotonously decreases from the crosslinked elastic polymer (B) layer toward the outermost polymer (C) layer. The manufacturing method of the acrylic resin film in any one of Claims 1-5 characterized by these.   Monomer comprising alkyl acrylate having an alkyl group having 1 to 8 carbon atoms and / or alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms and a graft crossing agent, which are constituents of innermost polymer (A) An emulsion prepared by mixing the mixture with water and a surfactant is supplied to the reaction vessel and polymerized, and then a crosslinked elastic polymer (B) layer, an intermediate polymer (D) layer, and an outermost polymer (C) layer. 7. The method for producing an acrylic resin film according to claim 6, wherein the monomer or monomer mixture constituting the polymer is sequentially supplied to the reaction vessel to polymerize the multilayer structure polymer.

Images