JP4287014B2

JP4287014B2 - Injection molding simultaneous painting sheet and injection molding simultaneous painting method

Info

Publication number: JP4287014B2
Application number: JP2000043932A
Authority: JP
Inventors: 功田島
Original assignee: Dai Nippon Printing Co Ltd
Current assignee: Dai Nippon Printing Co Ltd
Priority date: 2000-02-22
Filing date: 2000-02-22
Publication date: 2009-07-01
Anticipated expiration: 2020-02-22
Also published as: JP2001232660A

Description

【０００１】
【発明の属する技術分野】
本発明は、射出成形同時絵付用シートと、それを用いた射出成形同時絵付方法に関する。特に、切断端面が目立ちくく且つ絵柄の発色も良い絵付用シートと、それを用いた射出成形同時絵付方法に関する。
【０００２】
【従来の技術】
従来から、樹脂成形物の表面を加飾した絵付成形品が各種用途で使用されている。例えば、特公昭５０−１９１３２号公報、特公昭４３−２７４８８号公報等に開示の射出成形同時絵付方法等では、射出成形同時絵付用シートを射出成形の雌雄両型間に配置した後、溶融樹脂をキャビティ内に射出充填し固化させることで、樹脂成形物の成形と同時にその表面に射出成形同時絵付用シートを接着積層して一体化した絵付成形品を得る方法を開示している。
【０００３】
また、樹脂成形物に使用する射出成形樹脂としては、一般的にはＡＢＳ樹脂（アクリロニトリル−ブタジエン−スチレン共重合体）、アクリル樹脂、ポリカーボネート樹脂等が多かった。この為、射出成形同時絵付用シートも、その裏面側は、これら樹脂との密着性や成形性等を考慮して、ＡＢＳ樹脂シート等が多用されてきた。一方、絵付成形品に塗装感が要求される場合には、透明性に優れ、また成形性や耐候性、耐擦傷性等も良好な透明アクリル樹脂シートが表側に使用されてきた。そして、絵柄も付与する為には、成形性が良い上、印刷適性に優れる塩化ビニル樹脂シートに装飾層を印刷形成して使用する事が多かった。
【０００４】
そこで、射出成形同時絵付用シートとしては、上記の如き観点から、透明アクリル樹脂シート（表側）／装飾層が印刷された塩化ビニル樹脂シート／ＡＢＳ樹脂シートなる、樹脂シートが３層構成の絵付用シート等が使用されてきた。また、ＡＢＳ樹脂シートは通常黒色のものが用いられてきた。
【０００５】
【発明が解決しようとする課題】
しかしながら、上記の如き３層構成の場合、確かに塗装感、密着性、印刷適性等は全て一応満足するが、次の様な問題があった。
【０００６】
（Ａ）塩化ビニル樹脂が使用されている為に、不要となった時の廃棄燃焼時に塩化水素ガスを発生する等の点で、環境対応では無い。しかも、射出成形同時絵付後にトリミング（切断）された不要部分の射出成形同時絵付用シートを、リサイクルで成形樹脂として活かそうとすると、アクリル樹脂とＡＢＳ樹脂は同系等の樹脂の為、問題ないが、塩化ビニル樹脂が混入していると、リサイクが困難であった。また、塩化ビニル樹脂シートには、通常、成形性を付与する為に可塑剤が多量に混入されており、絵付成形品となった後に、経時的に可塑剤がブリードし、射出成形同時絵付用シート層内（透明アクリル樹脂シート／塩化ビニル樹脂シート間、及び塩化ビニル樹脂シート／ＡＢＳ樹脂シート間）の密着性が低下した。
【０００７】
（Ｂ）かと言って、塩化ビニル樹脂シートを省いて、透明アクリル樹脂シートの裏側面や、ＡＢＳ樹脂シートの表側面に装飾層を印刷して、これらを積層した樹脂シートが２層となる構成とすると、通常は黒色とする裏面側のＡＢＳ樹脂シートの色が絵柄の発色に悪影響した。それは、裏面側のＡＢＳ樹脂シートは、射出成形同時絵付用シートの切断端面は、それを黒くすると目立ち難くなる為に、黒色とする事が多いからである。このため、ＡＢＳ樹脂シートの黒色が装飾層による発色に悪影響しない様に、装飾層とＡＢＳ樹脂シート間に、全面ベタの着色隠蔽層を印刷形成する等して対処してきたが、印刷や塗工で形成する着色隠蔽層の厚みには限度があり、従って、隠蔽性には限界があった。
【０００８】
そこで、本発明の課題は、ラミネートタイプの射出成形同時絵付用シートにおいて、塗装感を有し且つ環境対応で、切断端面も目立ち難くした上で、絵柄の発色も良くする事である。また、塗装感を有し、切断端面が目立ち難くい上絵柄の発色も良い絵付成形品が得られる射出成形同時絵付方法とする事である。
【０００９】
【課題を解決するための手段】
そこで、上記課題を解決すべく、本発明の射出成形同時絵付用シートでは、ラミネートタイプの射出成形同時絵付用シートにおいて、透明アクリル樹脂シートの裏面側に、バインダーの樹脂に塩化ビニル−酢酸ビニル共重合体とアクリル樹脂との混合物を用いた装飾層、塩化ビニル−酢酸ビニル共重合体とアクリル樹脂との混合物からなる接着剤層、チタン白を少なくとも含む着色隠蔽ＡＢＳ樹脂シート、カーボンブラックを少なくとも含む黒色ＡＢＳ樹脂シートが、この順に積層されてなる構成とした。
【００１０】
或いはまた本発明の射出成形同時絵付用シートは、上記構成に対して、装飾層と接着剤層との位置関係を逆にした構成として、ラミネートタイプの射出成形同時絵付用シートにおいて、透明アクリル樹脂シートの裏面側に、塩化ビニル−酢酸ビニル共重合体とアクリル樹脂との混合物からなる接着剤層、バインダーの樹脂に塩化ビニル−酢酸ビニル共重合体とアクリル樹脂との混合物を用いた装飾層、チタン白を少なくとも含む着色隠蔽ＡＢＳ樹脂シート、カーボンブラックを少なくとも含む黒色ＡＢＳ樹脂シートが、この順に積層されてなる構成とした。
【００１１】
射出成形同時絵付用シートを上記いずれかの構成とすることで、先ず、塩化ビニル樹脂シートは使用せず、環境対応となる。また、表側の透明アクリル樹脂シートによって塗装感を付与できる。しかも、裏側の黒色ＡＢＳ樹脂シートによって、切断端面に黒色を出して目立ち難くし、且つ、ＡＢＳ樹脂、ＡＳ樹脂等のスチレン系の射出成形樹脂との密着性も確保できる。しかも、表面側の透明アクリル樹脂シートの下側の装飾層と、裏面側の黒色ＡＢＳ樹脂シートの間には、チタン色を含む着色隠蔽ＡＢＳ樹脂シートを設けてあるので、隠蔽性は十分確保でき、裏面側の黒色ＡＢＳ樹脂シートの黒色が、装飾層の発色に悪影響しない。その上、装飾層を特定樹脂とし、且つ装飾層と透明アクリル樹脂シート間、或いは着色隠蔽ＡＢＳ樹脂シートの間には、装飾層の特定樹脂と同様の特定樹脂の接着剤層を設けてある為、射出成形同時絵付用シート全層間の密着性も確保できる。なお、接着剤層の位置に２形態があるのは、射出成形同時絵付用シートを製造時に、装飾層の印刷対象（透明アクリル樹脂シート、或いは着色隠蔽ＡＢＳ樹脂シート）に何を選択するかの違いによる。
【００１２】
また、本発明の射出成形同時絵付方法としては、上記いずれかの射出成形同時絵付用シートを、一対の型の間に配置した後、両型を型締めし、両型で形成されるキャビティ内に流動状態の樹脂を射出し充填して固化させて、樹脂成型物の成形と同時にその表面に射出成形同時絵付用シートが積層一体化された絵付成形品を得る様にした。
【００１３】
この様に、上記いずれかの本発明の射出成形同時絵付用シートを使用して射出成形同時絵付けを行うことで、塗装感を有し、絵付用シートの切断端面が目立ち難くい上、絵柄の発色も良い絵付成形品が得られる、しかも、射出成形同時絵付方法及び絵付成形品を環境対応とする事ができる。
【００１４】
【発明の実施の形態】
以下、本発明の実施の形態を説明する。
【００１５】
射出成形同時絵付用シート：
図１の断面図で、本発明の射出成形同時絵付用シートの形態例を示す。図１（Ａ）に示す射出成形同時絵付用シートＳは、表側とする面は、透明アクリル樹脂シート１からなり、その裏面側に、バインダーの樹脂に塩化ビニル−酢酸ビニル共重合体とアクリル樹脂との混合物を用いた装飾層２、塩化ビニル−酢酸ビニル共重合体とアクリル樹脂との混合物からなる接着剤層３、チタン白を少なくとも含む着色隠蔽ＡＢＳ樹脂シート４、カーボンブラックを少なくとも含む黒色ＡＢＳ樹脂シート５が、順次積層された構成の絵付用シートである。
また、図１（Ｂ）に示す射出成形同時絵付用シートＳは、図１（Ａ）とは装飾層２と接着剤層３の上下関係が逆になった形態であり、表側とする面は、透明アクリル樹脂シート１からなり、その裏面側に、塩化ビニル−酢酸ビニル共重合体とアクリル樹脂との混合物からなる接着剤層３、バインダーの樹脂に塩化ビニル−酢酸ビニル共重合体とアクリル樹脂との混合物を用いた装飾層２、チタン白を少なくとも含む着色隠蔽ＡＢＳ樹脂シート４、カーボンブラックを少なくとも含む黒色ＡＢＳ樹脂シート５が、順次積層された構成の絵付用シートである。
【００１６】
以下、更に各層について詳述する。
【００１７】
〔透明アクリル樹脂シート〕
透明アクリル樹脂シート１は、アクリル樹脂からなる透明な樹脂シートである、該アクリル樹脂としては、例えば、ポリメチル（メタ）アクリレート、ポリブチル（メタ）アクリレート、メチル（メタ）アクリレート−ブチル（メタ）アクリレート共重合体、メチル（メタ）アクリレート−スチレン共重合体等のアクリル樹脂〔但し、（メタ）アクリレートとは、アクリレート又はメタクリレートの意味〕を単体又は２種以上の混合物として用いる。透明アクリル樹脂シートによる優れた透明性によって、塗装感、或いは表面艶等の高級感溢れる意匠性を付与出来る。また、透明樹脂シートとしてポリオレフィン系樹脂シート等を使用する場合に比べて、耐候性及び耐擦傷性等の表面物性も良好にできる利点もある。
【００１８】
なお、透明アクリル樹脂シートの透明とは、通常は無着色透明とするが、必要に応じ適宜、着色剤を樹脂中に添加して、着色透明としても良い。また、半透明としても良い。なお、着色剤としては、後述装飾層で列記する如き公知のものが使用できる。
【００１９】
また、透明アクリル樹脂シート中には、必要に応じて、適宜、ポリエチレンワックス、パラフィンワックス等の滑剤、シリカ、球状α−アルミナ、鱗片状α−アルミナ等の粒子からなる減摩剤、ベンゾトリアゾール系、ベンゾフェノン系、微粒子酸化セリウム系等の紫外線吸収剤、ヒンダードアミン系ラジカル捕捉剤等の光安定剤、或いは、炭酸カルシウム、硫酸バリウム、酸化アルミニウム等の粒子からなる充填剤、安定剤等の各種添加剤を、物性調整の為に添加しても良い。但し、透明アクリル樹脂シートが不透明とならない範囲内で添加する。
【００２０】
なお、透明アクリル樹脂シートの厚みは特に制限は無いが、通常５０〜２５０μｍ程度とする。
【００２１】
〔装飾層〕
装飾層２は、印刷等で例えば絵柄等を表現した層であり、装飾層２は、そのバインダーの樹脂に特定の樹脂を使用する。すなわち、バインダーの樹脂に、塩化ビニル−酢酸ビニル共重合体とアクリル樹脂との混合物を使用する。
この様な特定樹脂を使用する事で、装飾層が接する透明アクリル樹脂シート〔或いは着色隠蔽ＡＢＳ樹脂シート（図１（Ｂ）の形態）〕と、（該装飾層のバインダーの樹脂に対応した特定樹脂を使用する）接着剤層、ひいては、該接着剤層が接する着色隠蔽ＡＢＳ樹脂シート〔或いは透明アクリル樹脂シート（図１（Ｂ）の形態）〕との密着性が良好となる。すなわち、透明アクリル樹脂シートと着色隠蔽ＡＢＳ樹脂シートとの密着性が良好となる。なお、バインダーの樹脂中の、アクリル樹脂は透明アクリル樹脂シートとの密着性向上に寄与し、塩化ビニル−酢酸ビニル共重合体は印刷適性や成形適性向上に寄与する。
【００２２】
上記塩化ビニル−酢酸ビニル共重合体としては、通常、酢酸ビニル含有量が５〜２０質量％程度、平均重合度３５０〜９００程度のものが用いられる。また、塩化ビニル−酢酸ビニル共重合体は、必要に応じ、更にマレイン酸、フマル酸、（メタ）アクリル酸等のカルボン酸を共重合させたものでも良い。
【００２３】
また、上記アクリル樹脂としては、例えば、ポリメチル（メタ）アクリレート、ポリブチル（メタ）アクリレート、メチル（メタ）アクリレート−ブチル（メタ）アクリレート共重合体、メチル（メタ）アクリレート−スチレン共重合体等のアクリル樹脂、或いは、メチル（メタ）アクリレート、エチル（メタ）アクリレート、ブチル（メタ）アクリレート、オクチル（メタ）アクリレート、シクロヘキシル（メタ）アクリレート等と、２−ヒドロキシエチル（メタ）アクリレート、２−ヒドロキシ−３−フェノキシプロピル（メタ）アクリレート等の分子中に水酸基を有する（メタ）アクリル酸エステルとを共重合させて得られるアクリルポリオール等のアクリル樹脂を、単体又は２種以上混合して使用する。アクリルポリオールを用いた場合には、必要に応じて、２，４−トリレンジイソシアネート、１，６−ヘキサメチレンジイソシアネート等のイソシアネートを添加して架橋しても良い。なお、（メタ）アクリレートとはアクリレート又はメタクリレートの意味である。
【００２４】
また、塩化ビニル−酢酸ビニル共重合体とアクリル樹脂との混合割合は、塩化ビニル−酢酸ビニル共重合体／アクリル樹脂＝１／９〜９／１（質量比）程度で使用する。
【００２５】
なお、装飾層のバインダーの樹脂としては、副成分の樹脂として、必要に応じて、適宜、上記以外のその他の樹脂、例えば、熱可塑性ポリエステル樹脂、熱可塑性や２液硬化型等のウレタン樹脂等の樹脂を併用しても良い。
【００２６】
装飾層２は、バインダーの樹脂を上記特定樹脂から構成する他は、基本的には特に制限は無い。装飾層２は、通常は印刷インキ又は塗料で、公知の印刷又は塗工法（塗工法は全ベタ柄のとき）により形成する。通常、装飾層２は、透明アクリル樹脂シート１、或いは着色隠蔽ＡＢＳ樹脂シート４に対して印刷法等で形成する。
【００２７】
また、上記印刷インキ（或いは塗料）に用いる着色剤は公知の染料や顔料で良く、例えばチタン白、カーボンブラック、鉄黒、弁柄、黄鉛、コバルトブルー等の無機顔料、アニリンブラック、フタロシアニンブルー、イソインドリノンイエロー、キナクリドンレッド等の有機顔料、アルミニウム箔粉等の金属顔料、二酸化チタン被覆雲母箔粉等の真珠光沢（パール）顔料、その他染料等を用いる。
装飾層の絵柄は、木目、石目、布目、砂目、皮絞模様、幾何学模様、文字、記号、全面ベタ等と任意である。
【００２８】
なお、装飾層としては、木目柄等による装飾目的の層の他に、導電体層、磁性体層等の機能層でも良い。例えば、導電体層では、上記特定樹脂のバインダー中に含有させる材料として、着色剤の代わりに銀粉等の導電性粉末を分散させる。また、磁性体層の場合には、着色剤の代わりに、酸化鉄（γ−Ｆｅ₂Ｏ₃）等から成る磁性体粉末を分散させる。
【００２９】
〔接着剤層〕
接着剤層３は、塩化ビニル−酢酸ビニル共重合体とアクリル樹脂との混合物からなる構成する。これら樹脂は、装飾層のバインダーの樹脂と同じ樹脂である。従って、これにら樹脂については、前記装飾層のバインダーの樹脂として説明したので、説明は省略する。但し、両樹脂の内容、及び両樹脂の混合比率は装飾層と完全同一にする必要は無い。接着性、印刷・塗工適性等に応じた適宜内容とすれば良い。接着剤層は、装飾層が形成された樹脂シートを他の樹脂シートに熱融着で接着積層し易い様にする為に設ける。従って、装飾層２を透明アクリル樹脂シート１に対して形成した場合は、装飾層２の下側（着色隠蔽ＡＢＳ樹脂シート４側）となる位置に接着剤層３を設ける〔図１（Ａ）参照〕。一方、装飾層２を着色隠蔽ＡＢＳ樹脂シート４に対して形成した場合は、装飾層２の上側（透明アクリル樹脂シート１側）となる位置に接着剤層３を設ける〔図１（Ｂ）参照〕。接着剤層３の形成対象は、例えば、図１（Ａ）の形態で言えば、装飾層２形成済みの透明アクリル樹脂シート１の装飾層の面、或いは、図１（Ｂ）の形態で言えば、着色隠蔽ＡＢＳ樹脂シート４の透明アクリル樹脂シート１側である。
なお、わざわざ装飾層と同じ樹脂系の接着剤層を設けるのは、着色剤等をバインダーの樹脂中に含有する為に低下気味となる装飾層の接着性を、この接着剤層で補う為である。
なお、接着剤層は、上記特定樹脂を含むインキ（或いは塗液）を用いて、公知の印刷法（或いは塗工法）で形成すれば良い。接着剤層の厚みは特に制限はないが、例えば５〜２０μｍ程度である。
【００３０】
〔着色隠蔽ＡＢＳ樹脂シート〕
着色隠蔽ＡＢＳ樹脂シート４は、下地の黒色ＡＢＳ樹脂シート５の黒色を隠しして装飾層３による絵柄の発色を良くする為に設ける。ＡＢＳ樹脂シートを着色隠蔽性とするには、例えば、白色顔料を添加したＡＢＳ樹脂を使用すれば良い。白色顔料としては、例えば、チタン白、亜鉛華、三酸化二アンチモン等を用いる。なかでも、チタン白が隠蔽性、耐候性、耐熱性、その他物性の点で好ましい。また、必要に応じて更に、装飾層の絵柄の基調色となる着色剤を添加しても良い。この着色剤としては、前記装飾層で述べた公知の各種顔料や染料等を使用すれば良い。隠蔽性確保の為に添加する顔料としては、隠蔽性の他に任意の絵柄の発色にも汎用的に使用できる点で、可視光線帯域内の分光反射スペクトルが一様な（無彩色の）白色顔料のみが好ましい。しかし、着色隠蔽ＡＢＳ樹脂シートを白色とした場合、この下には、絵付用シートの切断端面を目立ち難くする為に黒色とした黒色ＡＢＳ樹脂シートが有るので、それに反してシート切断端面が、白／黒の２層となって目立ち易くなってしまう。その為、シート切断端面が目に触れる構成の絵付成形品には不向きである。この為、この様な場合も含めて、シート切断端面を目立ち難くするには、白色顔料の他に、絵柄の色相と同様の色相の顔料を添加すると良く、更に黒色顔料（例えばカーボンブラック、鉄黒等）も発色を阻害しない範囲で加えると尚更良い。なお、白色顔料に併用して顔料を着色剤として使用する場合、隠蔽性は顔料よりも劣るが染料を使用しても良い。但し、白色顔料に顔料や染料等の着色剤を併用する場合は、発色及びその汎用性は低下するので、適宜使い分けると良い。
【００３１】
なお、上の装飾層３と下の黒色ＡＢＳ樹脂シート５間の隠蔽層として、樹脂シートを用い、しかもこの樹脂にＡＢＳ樹脂を使用するのは、絵付用シート裏面の黒色ＡＢＳ樹脂シートとの良好な密着性を確保できるからである。
なお、使用するＡＢＳ樹脂（アクリロニトリル−ブタジエン−スチレン共重合体）としては、公知の各種グレードの樹脂を用途に応じて使用すれば良い。
また、着色隠蔽ＡＢＳ樹脂シートの厚さは、最低限、隠蔽性が確保できる厚さとすれば良い。用途にもよるが、通常、厚さは３０〜２００μｍ程度とする。
【００３２】
〔黒色ＡＢＳ樹脂シート〕
黒色ＡＢＳ樹脂シート５は、射出成形同時絵付用シートの裏側となる層であり、この層にＡＢＳ樹脂シートを採用する事で、射出成形同時絵付用シートを、ＡＢＳ樹脂、ＡＳ樹脂（アクリロニトリル−スチレン共重合体）、ＰＳ樹脂（ポリスチレン）等のスチレン系樹脂からなる樹脂成形物に、密着良くラミネ−ト出来る様になる。そして、この樹脂シートを黒色とする事によって、射出成形同時絵付用シートの切断端面を目立ち難くできる。ＡＢＳ樹脂シートを黒色とするには、例えば、カーボンブラック、鉄黒等の黒色顔料を添加したＡＢＳ樹脂を使用すれば良い。なかでも、カーボンブラックは（黒色の）発色、耐候性、その他物性の点で好ましい。
なお、使用するＡＢＳ樹脂としては、公知の各種グレードの樹脂を用途に応じて使用すれば良い。また、黒色ＡＢＳ樹脂シートの厚さは特に限定は無いが、射出成形同時絵付用シート全体としての必要な総厚等を考慮して、通常１００〜３００μｍ程度とする。
【００３３】
〔その他〕
なお、射出成形同時絵付用シートの各層を上記構成に積層するには、例えば、図１（Ａ）の如き層構成の場合は、次の様にすれば良い。透明アクリル樹脂シート１の裏面に装飾層２を印刷し、更に続いて接着剤層３を塗工又は印刷して形成した印刷シートを用意する。一方、黒色ＡＢＳ樹脂シート５と着色隠蔽ＡＢＳ樹脂シート４をそれぞれ用意し、これら両ＡＢＳ樹脂シート同士を、熱融着法で、或いは間にウレタン樹脂系接着剤等を用いたドライラミネーション法によって、貼り合わせて積層シートとする。そして、前記印刷シートとこの積層シートとを、前記印刷シートの接着剤層の熱融着によって、積層すれば良い。なお、黒色ＡＢＳ樹脂シートと着色隠蔽ＡＢＳ樹脂シートとは、２層共押出法によって、シート成膜と同時に積層しても良い。
【００３４】
射出成形同時絵付方法：
本発明の射出成形同時絵付方法は、上述した本発明の射出成形同時絵付用シートを用いて、所謂射出成形同時絵付方法によって、該絵付用シートを樹脂成形物の表面に積層一体化して、該絵付用シートで絵付けされた絵付成形品を得る方法である。
【００３５】
なお、射出成形同時絵付方法とは、特公昭５０−１９１３２号公報、特公昭４３−２７４８８号公報等に記載されるように、射出成形同時絵付用シートを射出成形の雌雄両型間に配置した後、流動状態の樹脂を型内に射出充填し、樹脂成型物の成形と同時にその表面に射出成形同時絵付用シートを積層一体化して絵付けする方法である。
【００３６】
本発明の射出成形同時絵付方法は、用いる絵付用シートとして前述した本発明の射出成形同時絵付用シートを用いる事以外は、従来公知の射出成形同時絵付方法に於ける各種形態をとり得るものである。例えば、絵付用シートの予備成形を行う形態でも行わない形態でも、いずれでも良い。また、絵付用シートの予熱を行っても良く、行わなくても良い。なお、予備成形時には通常は絵付用シートは予熱する。
【００３７】
なお、もちろんの事だが、絵付用シートの絞りが大きい場合は、予備成形を行うのが好ましい。一方、絵付用シートの絞りが少ない場合は、射出される流動状態の樹脂の樹脂圧のみで絵付用シートを成形しても良い。この際、絞りが浅ければ、予備成形無しで樹脂射出と同時に型内に充填される流動状態の樹脂の樹脂圧で絵付用シートを成形しても良い。また、樹脂圧で絵付用シートを成形する場合でも、絵付用シートは予熱せずに射出樹脂の熱を利用する事もある。また、絵付用シートの予備成形は、通常は、射出成形型を真空成形型と兼用して行うが（インライン予備成形）、型間に絵付用シートを供給する前に、型外部で別の真空成形型で絵付用シートを真空成形する様な予備成形（オフライン予備成形）でも良い。但し、予備成形は、射出成形型と真空成形型とを兼用して行う形態が効率的且つ精度良く絵付用シートを積層できる点で好ましい。しかし、予備成形済みの絵付用シートを予め別の場所で纏めて製造しておく場合等では、予備成形はオフライン予備成形の形態が好ましい。なお、本発明の説明に於いて真空成形とは真空圧空成形も包含する。
なお、本発明の射出成形同時絵付方法で用いる射出成形同時絵付用シートは、枚葉、連続帯状のどちらでも良い事はもちろんである。
【００３８】
図２の概念図によって、本発明の射出成形同時絵付方法を、その或る一形態で説明する。図２に示す形態では、射出成形型とは別の型である真空成形型で、射出成形同時絵付用シートを加熱し軟化させて予備成形した後に、成形された射出成形同時絵付用シートを射出成形型に挿入後、型締めして樹脂を射出する、オフライン予備成形による形態である。次に、この図２を用いて、この形態の射出成形同時絵付方法を更に説明する。
【００３９】
先ず、図２（Ａ）の如く、型面に吸引孔３１等の吸引手段を有する真空成形型Ｍｖを用いて、ヒータ３２で加熱軟化させた射出成形同時絵付用シートを真空成形により予備成形する。同図では、真空成形型Ｍｖは、後述の射出成形型Ｍｂに対して略同形状同凹凸の型面としてある。なお、真空成形型Ｍｖは、鉄やアルミニウム等の金属、或いはセラミックス等からなる。また、射出成形同時絵付用シートＳは適宜枠状のシートクランプ３３で固定する。この際、射出成形同時絵付用シートの裏側（黒色ＡＢＳ樹脂シート側）は、射出樹脂側（図面上方）となる向きとする。また、ヒータ３２による加熱軟化は、例えば非接触の輻射加熱とするが、接触による伝導加熱でも良い。そして、予備成形は、吸引孔から吸引して真空成形して、絵付用シートを真空成形型Ｍｖの型面に沿わせ真空成形する。なお、真空成形は圧空も併用する真空圧空成形でも良く、これも包含する。
【００４０】
次いで、予備成形された射出成形同時絵付用シートＳを、図２（Ｂ）の如く、一対の射出成形型ＭａとＭｂとの間に供給する。ここでは射出成形型Ｍａの方は射出ノズルと連通する湯道（ランナー）及び湯口（ゲート）を有し、射出成形型Ｍｂはそのキャビティ面が前記予備成形型Ｍｖの型面と同一又は略同一形状を成し、予備成形済みの絵付用シートを固定する型となる。これらの型は鉄等の金属、或いはセラミックスからなる。型開き状態に於いて両型Ｍａ、Ｍｂ間に絵付用シートＳを供給し、型Ｍｂに絵付用シートＳを枠状のシートクランプ４２で押圧する等して固定する。この際、射出成形同時絵付用シートの裏側（黒色ＡＢＳ樹脂シート側）は、図面右側の射出樹脂側となる様にする事はもちろんである。次いで、図２（Ｃ）の如く両型を型締めし、両型で形成されるキャビティに加熱熔融状態等の流動状態の樹脂を射出し充填する。そして、絵付用シートの不要部分がある場合は、それを適宜トリミング（切断）すれば、図３の断面図で概念的に示す如き、樹脂成形物６の表面に絵付用シートＳが積層した構成の絵付成形品Ｐが得られる。
【００４１】
なお、射出成形同時絵付方法に於いて、射出成形して樹脂成形物とする射出成形樹脂としては、従来公知のものが使用でき基本的には特に制限はなく、絵付成形品の要求物性やコスト等に応じて選定すれば良い。但し、本発明では、射出成形同時絵付用シートの裏面側にＡＢＳ樹脂を使用するので、これと密着が良いスチレン系樹脂が好適である。スチレン系樹脂は、例えば、ＡＢＳ樹脂、ＡＳ樹脂、ＰＳ樹脂等である。
【００４２】
なお、射出成形樹脂は、用途に応じて適宜、着色剤を添加して着色した樹脂を使用しても良い。着色剤には、前述装飾層で述べた如き公知の着色剤を使用できる。また、射出成形樹脂には、必要に応じて適宜、シリカ、アルミナ、炭酸カルシウム、水酸化アルミニウム等の無機物粉末、木粉、ガラス繊維等の充填剤、安定剤、滑剤、ゴム（エラストマー）等の公知の各種添加剤を含有させる。
【００４３】
図３は、得られる絵付成形品Ｐを例示する断面図であり、前述本発明の射出成形同時絵付用シートＳが樹脂成形物６の表面に積層した構成の成形品となる。図３では、射出成形同時絵付用シートＳ内の層構成の明示は省略してあるが、図１（Ａ）及び（Ｂ）に示した如き構成である。絵付成形品Ｐは、車両内装材、車両外装材、家電製品乃至は事務用機器のキャビネット、雑貨等各種用途に使用出来る。
【００４４】
【実施例】
以下、実施例により本発明を更に詳述する。
【００４５】
〔実施例〕
図１（Ｂ）の如き射出成形同時絵付用シートＳを、次の様にして作製した。先ず、ポリメチルメタクリレート（ＰＭＭＡ）を主成分として、これに脂肪族アルコール系滑剤を０．２質量％とベンゾトリアゾール系紫外線吸収剤を０．４質量％添加してなる、硝子平板面に対する動摩擦係数が０．４５である厚さ１２５μｍで無色の透明アクリル樹脂シート１と、顔料としてチタン白と弁柄を黄鉛を添加して黄色とした厚さ１００μｍの着色隠蔽ＡＢＳ樹脂シート４と、カーボンブラックを添加した厚さ３００μｍの黒色ＡＢＳ樹脂シート５とを用意した。
【００４６】
そして、着色隠蔽ＡＢＳ樹脂シート４に対して、バインダーの樹脂に塩化ビニル−酢酸ビニル共重合体とアクリル樹脂との１対１質量比の混合物を用い、着色剤に弁柄、黄鉛、フタロシアニンブルー、及びカーボンブラックを用いたインキで木目絵柄の装飾層２をグラビア印刷で形成し、更にその上に、塩化ビニル−酢酸ビニル共重合体とアクリル樹脂との２対８質量比の混合物からなる厚さ２μｍの接着剤層３をグラビア印刷で全面に形成して、印刷シートとした。
【００４７】
そして、着色隠蔽ＡＢＳ樹脂シート４からなる上記印刷シートの印刷面が、透明アクリル樹脂シート１側を向く様にして、該透明アクリル樹脂シート１と印刷シートと、黒色ＡＢＳ樹脂シート５とを重ね、輪転式ロール版プレス機を用いて、熱融着で積層して、本発明の射出成形同時絵付用シートとした。
【００４８】
更に、図２の概念図に示した様なオフライン予備成形の形態を採用した射出成形同時絵付方法によって、射出成形樹脂としてはＡＢＳ樹脂を使用して、上記射出成形同時絵付用シートを、樹脂成形物の表面に成形物の成形と同時に、積層一体化して、図３に示す如き、射出成形同時絵付用シートＳが樹脂成形物６に積層された絵付成形品Ｐを得た。
【００４９】
なお、射出成形同時絵付用シートの真空成形は、図２（Ａ）の様に、射出成形の雌型Ｍｂと同じキャビティ面を有するが、該雌型Ｍｂとは別体の真空成形型Ｍｖ上に、赤外線輻射式熱盤からなるヒータ３２にて、非接触状態で射出成形同時絵付用シートを１２０℃に加熱軟化させ、真空成形型Ｍｖに穿設した吸引孔３１から真空吸引して、真空成形型Ｍｖのキャビティ面上に予備成形し、冷却させて、予備成形済みの射出成形同時絵付用シートを脱型した。
そして、図２（Ｂ）の様に、この予備成形済みの射出成形同時絵付用シートを、その裏面（黒色ＡＢＳ樹脂シート側）が射出成形用の雄型Ｍａ側を向く様にして、シートクランプ４２で射出成形用の雌型Ｍｂに装着した後、図２（Ｃ）の様に、雌雄両型を型締めし、雌雄両型で形成されるキャビティ内に、ノズル温度２２０℃で加熱熔融したＡＢＳ樹脂を射出充填し冷却固化させると共に、該絵付用シートと一体化させた絵付成形品とした後、雌雄両型を型開きし、該絵付成形品を取り出した。
【００５０】
得られた絵付成形品は、高級感溢れる塗装感を有し、しかも、切断端面も目立ち難くい上、裏面のＡＢＳ樹脂シートの黒色が悪影響せず絵柄の発色も良かった。また、塩化ビニル樹脂シートは使用していないので、環境対応製品となり、また、トリミング後の不要の射出成形同時絵付用シートのリサイクルも容易なものとなった。
【００５１】
【発明の効果】
▲１▼本発明の射出成形同時絵付用シートによれば、切断端面が目立ち難くいにも拘らず、絵柄の発色も良い。また、塩化ビニル樹脂シート未使用の為に環境対応となる上、塗装感も得られる。また、絵付用シート内各層の密着性も良い。また、ＡＢＳ樹脂、ＡＳ樹脂、ＰＳ樹脂等のスチレン系樹脂の樹脂成形物との密着が良い。
▲２▼また、本発明の射出成形同時絵付方法によれば、塗装感を有し、絵付用シートの切断端面が目立ち難くい上、絵柄の発色も良い絵付成形品が得られる、しかも、塩化ビニル樹脂シート未使用の為、トリミング後の不要な射出成形同時絵付用シートのリサイクルも容易である上、絵付成形品を環境対応とする事ができる。
【図面の簡単な説明】
【図１】本発明の射出成形同時絵付用シートの形態例を示す断面図。
【図２】本発明の射出成形同時絵付方法をその一形態で説明する概念図。
【図３】本発明で得られる絵付成形品を例示する断面図。
【符号の説明】
１透明アクリル樹脂シート
２装飾層
３接着剤層
４着色隠蔽ＡＢＳ樹脂シート
５黒色ＡＢＳ樹脂シート
６樹脂成形物
３１吸引孔
３２ヒータ
３３シートクランプ
４２シートクランプ
Ｍａ射出成形型（雄型）
Ｍｂ射出成形型（雌型）
Ｍｖ真空成形型
Ｐ絵付成形品
Ｓ射出成形同時絵付用シート[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sheet for simultaneous injection molding and a method for simultaneous injection molding using the same. In particular, the present invention relates to a picture sheet with a conspicuous cut end face and good pattern coloring, and a method for simultaneous injection molding using the same.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a molded article with a picture that decorates the surface of a resin molded product has been used for various purposes. For example, in the injection molding simultaneous painting method disclosed in Japanese Patent Publication No. 50-19132, Japanese Patent Publication No. 43-27488, etc., after the injection molding simultaneous painting sheet is placed between both male and female molds of injection molding, the molten resin A method of obtaining a molded product with a picture by integrally injecting and laminating an injection molding simultaneous picture sheet on the surface thereof simultaneously with molding of a resin molded product by injection filling into a cavity and solidifying.
[0003]
Moreover, as injection molding resin used for a resin molding, generally there were many ABS resin (acrylonitrile-butadiene-styrene copolymer), an acrylic resin, a polycarbonate resin, etc. For this reason, ABS resin sheets and the like have been frequently used on the back side of injection-molded simultaneous painting sheets in consideration of adhesion to these resins and moldability. On the other hand, when a painted feeling is required for a molded article with a picture, a transparent acrylic resin sheet having excellent transparency and good moldability, weather resistance, scratch resistance and the like has been used on the front side. In order to provide a pattern, the decorative layer is often printed and used on a vinyl chloride resin sheet having good moldability and excellent printability.
[0004]
Therefore, as a sheet for simultaneous injection molding, from the above viewpoint, a transparent acrylic resin sheet (front side) / vinyl chloride resin sheet on which a decorative layer is printed / ABS resin sheet is used. Sheets and the like have been used. Also, the ABS resin sheet is usually black.
[0005]
[Problems to be solved by the invention]
However, in the case of the three-layer structure as described above, the coating feeling, adhesion, printability, etc. are all satisfied for the time being, but there are the following problems.
[0006]
(A) Since vinyl chloride resin is used, it is not environmentally friendly in that hydrogen chloride gas is generated during waste combustion when it is no longer needed. Moreover, if you try to use the injection molding simultaneous painting sheet of the unnecessary portion trimmed (cut) after the injection molding simultaneous painting as a molding resin by recycling, there is no problem because the acrylic resin and ABS resin are similar resins. When vinyl chloride resin is mixed, recycling is difficult. Also, vinyl chloride resin sheets are usually mixed with a large amount of plasticizer to give moldability, and after becoming a molded article, the plasticizer bleeds over time, for simultaneous injection molding. The adhesiveness in the sheet layer (between the transparent acrylic resin sheet / vinyl chloride resin sheet and between the vinyl chloride resin sheet / ABS resin sheet) was lowered.
[0007]
(B) However, the vinyl chloride resin sheet is omitted, and a decorative layer is printed on the back side surface of the transparent acrylic resin sheet or the front side surface of the ABS resin sheet, and the resin sheet obtained by laminating these layers is a two-layer structure. Then, the color of the ABS resin sheet on the back side, which is usually black, adversely affected the color development of the pattern. This is because the ABS resin sheet on the back side is often black because the cut end face of the sheet for simultaneous injection-molding painting is not noticeable when it is blackened. Therefore, in order to prevent the black color of the ABS resin sheet from adversely affecting the color developed by the decoration layer, we have dealt with it by printing a solid color concealment layer between the decoration layer and the ABS resin sheet. There is a limit to the thickness of the colored concealing layer formed in (1), and therefore there is a limit to the concealability.
[0008]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to improve the coloring of a pattern in a laminate-type injection-molded simultaneous painting sheet having a feeling of painting, being environmentally friendly, making the cut end face inconspicuous. Another object of the present invention is to provide a method for simultaneous painting with injection molding that can provide a molded article with a picture that has a feeling of painting and has a good coloring of the upper picture that is difficult to see the cut end face.
[0009]
[Means for Solving the Problems]
Therefore, in order to solve the above-mentioned problems, in the injection-molded simultaneous painting sheet of the present invention, in the laminate-type injection-molded simultaneous painting sheet, on the back side of the transparent acrylic resin sheet, the binder resin is vinyl chloride-vinyl acetate. Decorative layer using a mixture of polymer and acrylic resin, adhesive layer made of a mixture of vinyl chloride-vinyl acetate copolymer and acrylic resin, colored concealed ABS resin sheet containing at least titanium white, and at least carbon black A black ABS resin sheet was laminated in this order.
[0010]
Alternatively, the injection-molded simultaneous painting sheet of the present invention is a laminate type injection-molded simultaneous painting sheet in which the positional relationship between the decorative layer and the adhesive layer is reversed with respect to the above-described configuration. On the back side of the sheet, an adhesive layer made of a mixture of vinyl chloride-vinyl acetate copolymer and an acrylic resin, a decorative layer using a mixture of vinyl chloride-vinyl acetate copolymer and an acrylic resin as a binder resin, A colored concealed ABS resin sheet containing at least titanium white and a black ABS resin sheet containing at least carbon black are laminated in this order.
[0011]
By setting the sheet for simultaneous injection-molding with any of the above-described configurations, first, the vinyl chloride resin sheet is not used, and it becomes environmentally friendly. Moreover, a coating feeling can be provided by the transparent acrylic resin sheet on the front side. In addition, the black ABS resin sheet on the back side makes the cut end surface black and less noticeable, and can also ensure adhesion with styrene-based injection molding resins such as ABS resin and AS resin. Moreover, since a colored concealed ABS resin sheet containing a titanium color is provided between the lower decorative layer on the transparent acrylic resin sheet on the front side and the black ABS resin sheet on the back side, sufficient concealment can be ensured. The black color of the black ABS resin sheet on the back side does not adversely affect the coloring of the decorative layer. In addition, because the decorative layer is a specific resin and an adhesive layer of the same specific resin as the specific resin of the decorative layer is provided between the decorative layer and the transparent acrylic resin sheet or between the colored concealed ABS resin sheet. Moreover, the adhesion between all layers of the sheet for simultaneous injection-molding can be ensured. In addition, there are two forms in the position of the adhesive layer. What is selected for the print target (transparent acrylic resin sheet or colored concealed ABS resin sheet) of the decoration layer when manufacturing the sheet with simultaneous injection molding picture It depends on the difference.
[0012]
In the injection molding simultaneous painting method of the present invention, any one of the above injection molding simultaneous painting sheets is placed between a pair of molds, then both molds are clamped, and the cavity is formed by both molds. The resin in a fluid state was injected, filled and solidified to obtain a picture molded product in which a sheet for simultaneous injection molding was laminated and integrated on the surface simultaneously with molding of the resin molding.
[0013]
Thus, by performing simultaneous injection molding using the injection molding simultaneous painting sheet of any of the present invention, it has a feeling of painting, and the cut end surface of the painting sheet is not easily noticeable. In addition, it is possible to obtain a molded article with good coloration, and to make the injection molding simultaneous painting method and the molded article with an environment compatible.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
[0015]
Sheet for simultaneous injection molding:
The cross-sectional view of FIG. 1 shows an example of the form of the injection-molded simultaneous painting sheet of the present invention. The sheet S for simultaneous injection-molding shown in FIG. 1A has a transparent acrylic resin sheet 1 on the front side, and a vinyl chloride-vinyl acetate copolymer and an acrylic resin as a binder resin on the back side. Decorative layer 2 using a mixture thereof, adhesive layer 3 composed of a mixture of vinyl chloride-vinyl acetate copolymer and acrylic resin, colored concealed ABS resin sheet 4 containing at least titanium white, and black ABS containing at least carbon black The resin sheet 5 is a sheet for painting having a configuration in which the resin sheets 5 are sequentially laminated.
Moreover, the sheet S for simultaneous injection molding picture shown in FIG. 1 (B) is a form in which the vertical relationship between the decorative layer 2 and the adhesive layer 3 is reversed from that in FIG. 1 (A). The transparent acrylic resin sheet 1 has an adhesive layer 3 made of a mixture of a vinyl chloride-vinyl acetate copolymer and an acrylic resin on the back side, and a vinyl chloride-vinyl acetate copolymer and an acrylic resin as a binder resin. The decorative layer 2 using a mixture of the above, a colored concealed ABS resin sheet 4 containing at least titanium white, and a black ABS resin sheet 5 containing at least carbon black are sheets for painting having a structure in which they are sequentially laminated.
[0016]
Hereinafter, each layer will be described in detail.
[0017]
[Transparent acrylic resin sheet]
The transparent acrylic resin sheet 1 is a transparent resin sheet made of an acrylic resin. Examples of the acrylic resin include polymethyl (meth) acrylate, polybutyl (meth) acrylate, and methyl (meth) acrylate-butyl (meth) acrylate. Acrylic resins such as a polymer and methyl (meth) acrylate-styrene copolymer (where (meth) acrylate means acrylate or methacrylate) are used alone or as a mixture of two or more. Due to the excellent transparency of the transparent acrylic resin sheet, it is possible to impart a high-quality design such as a feeling of painting or surface gloss. Further, there is an advantage that surface properties such as weather resistance and scratch resistance can be improved as compared with the case where a polyolefin resin sheet or the like is used as the transparent resin sheet.
[0018]
The transparency of the transparent acrylic resin sheet is usually non-colored and transparent, but if necessary, a colorant may be appropriately added to the resin to make it colored and transparent. Further, it may be translucent. In addition, as a coloring agent, the well-known thing as listed by the below-mentioned decoration layer can be used.
[0019]
In addition, in the transparent acrylic resin sheet, if necessary, lubricants such as polyethylene wax and paraffin wax, lubricants composed of particles of silica, spherical α-alumina, scaly α-alumina, benzotriazole-based , Benzophenone-based, fine particle cerium oxide-based ultraviolet absorbers, hindered amine-based radical scavengers, etc., light stabilizers such as calcium carbonate, barium sulfate, aluminum oxide particles, various additives such as stabilizers May be added to adjust the physical properties. However, the transparent acrylic resin sheet is added within a range that does not become opaque.
[0020]
The thickness of the transparent acrylic resin sheet is not particularly limited, but is usually about 50 to 250 μm.
[0021]
[Decoration layer]
The decorative layer 2 is a layer that expresses, for example, a pattern or the like by printing or the like, and the decorative layer 2 uses a specific resin as the binder resin. That is, a mixture of vinyl chloride-vinyl acetate copolymer and acrylic resin is used as the binder resin.
By using such a specific resin, a transparent acrylic resin sheet [or colored concealed ABS resin sheet (form of FIG. 1 (B))] in contact with the decorative layer, and a specific corresponding to the resin of the binder of the decorative layer Adhesiveness with the adhesive layer (using resin) and by extension, the colored concealed ABS resin sheet (or the transparent acrylic resin sheet (form of FIG. 1B)) with which the adhesive layer is in contact is improved. That is, the adhesion between the transparent acrylic resin sheet and the colored concealed ABS resin sheet is improved. The acrylic resin in the binder resin contributes to improving the adhesion to the transparent acrylic resin sheet, and the vinyl chloride-vinyl acetate copolymer contributes to improving printability and moldability.
[0022]
As the vinyl chloride-vinyl acetate copolymer, those having a vinyl acetate content of about 5 to 20% by mass and an average degree of polymerization of about 350 to 900 are usually used. The vinyl chloride-vinyl acetate copolymer may be further copolymerized with a carboxylic acid such as maleic acid, fumaric acid or (meth) acrylic acid, if necessary.
[0023]
Examples of the acrylic resin include acrylics such as polymethyl (meth) acrylate, polybutyl (meth) acrylate, methyl (meth) acrylate-butyl (meth) acrylate copolymer, and methyl (meth) acrylate-styrene copolymer. Resin, or methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, octyl (meth) acrylate, cyclohexyl (meth) acrylate, etc., 2-hydroxyethyl (meth) acrylate, 2-hydroxy-3 -An acrylic resin such as an acrylic polyol obtained by copolymerizing a (meth) acrylic acid ester having a hydroxyl group in a molecule such as phenoxypropyl (meth) acrylate is used alone or in combination of two or more. When an acrylic polyol is used, it may be cross-linked by adding an isocyanate such as 2,4-tolylene diisocyanate or 1,6-hexamethylene diisocyanate as necessary. (Meth) acrylate means acrylate or methacrylate.
[0024]
The mixing ratio of the vinyl chloride-vinyl acetate copolymer and the acrylic resin is such that the vinyl chloride-vinyl acetate copolymer / acrylic resin is about 1/9 to 9/1 (mass ratio).
[0025]
In addition, as a binder resin of the decoration layer, as a subcomponent resin, if necessary, other resins other than those described above, for example, a thermoplastic polyester resin, a urethane resin such as thermoplastic or two-component curable resin, etc. These resins may be used in combination.
[0026]
The decorative layer 2 is basically not particularly limited except that the binder resin is composed of the specific resin. The decorative layer 2 is usually formed of printing ink or paint, and is formed by a known printing or coating method (when the coating method is a solid pattern). Usually, the decoration layer 2 is formed on the transparent acrylic resin sheet 1 or the colored concealed ABS resin sheet 4 by a printing method or the like.
[0027]
The colorant used in the printing ink (or paint) may be a known dye or pigment, for example, inorganic pigments such as titanium white, carbon black, iron black, petal, yellow lead, cobalt blue, aniline black, phthalocyanine blue. Organic pigments such as isoindolinone yellow and quinacridone red, metal pigments such as aluminum foil powder, pearlescent pigments such as titanium dioxide-coated mica foil powder, and other dyes are used.
The pattern of the decoration layer is arbitrary, such as wood grain, stone grain, cloth grain, sand grain, leather-drawn pattern, geometric pattern, characters, symbols, full-color solid, and the like.
[0028]
The decorative layer may be a functional layer such as a conductor layer or a magnetic layer, in addition to a layer for decorative purposes such as a wood grain pattern. For example, in the conductor layer, conductive powder such as silver powder is dispersed instead of the colorant as a material to be contained in the binder of the specific resin. In the case of a magnetic layer, iron oxide (γ-Fe is used instead of the colorant.₂O_Three) Etc. are dispersed.
[0029]
[Adhesive layer]
The adhesive layer 3 is composed of a mixture of a vinyl chloride-vinyl acetate copolymer and an acrylic resin. These resins are the same resins as the binder resin of the decorative layer. Therefore, since these resins have been described as the binder resin of the decorative layer, description thereof will be omitted. However, the contents of both resins and the mixing ratio of both resins need not be the same as those of the decorative layer. What is necessary is just to make it the content suitably according to adhesiveness, printing / coating suitability, etc. The adhesive layer is provided so that the resin sheet on which the decoration layer is formed can be easily bonded and laminated to another resin sheet by thermal fusion. Therefore, when the decoration layer 2 is formed on the transparent acrylic resin sheet 1, the adhesive layer 3 is provided at a position below the decoration layer 2 (colored concealed ABS resin sheet 4 side) [FIG. reference〕. On the other hand, when the decorative layer 2 is formed on the colored concealed ABS resin sheet 4, the adhesive layer 3 is provided at a position on the upper side of the decorative layer 2 (the transparent acrylic resin sheet 1 side) [see FIG. ]. The formation target of the adhesive layer 3 can be said, for example, in the form of FIG. 1A, in the form of the decorative layer surface of the transparent acrylic resin sheet 1 on which the decoration layer 2 has been formed, or in the form of FIG. For example, it is the transparent acrylic resin sheet 1 side of the colored concealed ABS resin sheet 4.
The purpose of providing the same resin-based adhesive layer as that for the decorative layer is to supplement the adhesiveness of the decorative layer, which tends to be lowered due to the inclusion of a colorant or the like in the resin of the binder, with this adhesive layer. is there.
In addition, what is necessary is just to form an adhesive bond layer by the well-known printing method (or coating method) using the ink (or coating liquid) containing the said specific resin. Although there is no restriction | limiting in particular in the thickness of an adhesive bond layer, For example, it is about 5-20 micrometers.
[0030]
[Colored hiding ABS resin sheet]
The colored concealing ABS resin sheet 4 is provided to conceal the black color of the underlying black ABS resin sheet 5 and improve the color of the pattern by the decorative layer 3. In order to make the ABS resin sheet color-hiding, for example, an ABS resin to which a white pigment is added may be used. As the white pigment, for example, titanium white, zinc white, antimony trioxide and the like are used. Of these, titanium white is preferable in terms of concealability, weather resistance, heat resistance, and other physical properties. Moreover, you may add the coloring agent used as the base color of the pattern of a decoration layer further as needed. As the colorant, any of various known pigments and dyes described in the decoration layer may be used. The pigment added to ensure concealment is white (achromatic) with a uniform spectral reflection spectrum in the visible light band, in addition to concealment, it can also be used for coloration of arbitrary patterns. Only pigments are preferred. However, when the colored concealed ABS resin sheet is white, there is a black ABS resin sheet that is black to make the cut end face of the painting sheet inconspicuous. On the contrary, the sheet cut end face is white. / It becomes two layers of black and it becomes easy to stand out. Therefore, it is not suitable for a molded article with a picture having a configuration in which the sheet cutting end face is in contact with the eyes. For this reason, in order to make the cut end face of the sheet inconspicuous in such cases, a pigment having a hue similar to the hue of the pattern may be added in addition to the white pigment, and a black pigment (for example, carbon black, iron It is even better if black is added as long as color development is not hindered. When a pigment is used as a colorant in combination with a white pigment, a hiding property is inferior to that of the pigment, but a dye may be used. However, when a colorant such as a pigment or a dye is used in combination with a white pigment, the color development and its versatility are reduced, so it is preferable to use them appropriately.
[0031]
The resin layer is used as a concealing layer between the upper decorative layer 3 and the lower black ABS resin sheet 5, and the ABS resin is used for this resin because it is good with the black ABS resin sheet on the back of the painting sheet. This is because a good adhesion can be secured.
In addition, what is necessary is just to use resin of various well-known grades as an ABS resin (acrylonitrile-butadiene-styrene copolymer) to be used according to a use.
Further, the thickness of the colored concealing ABS resin sheet may be at least a thickness that can ensure concealment. Although it depends on the application, the thickness is usually about 30 to 200 μm.
[0032]
[Black ABS resin sheet]
The black ABS resin sheet 5 is a layer on the back side of the injection-molded simultaneous painting sheet. By adopting an ABS resin sheet in this layer, the injection-molded simultaneous painting sheet is made of ABS resin, AS resin (acrylonitrile-styrene). Copolymer) and PS resin (polystyrene) and other resin moldings made of styrene resin can be laminated with good adhesion. And by making this resin sheet black, the cut end face of the sheet for simultaneous injection-molding painting can be made inconspicuous. In order to make the ABS resin sheet black, for example, an ABS resin to which a black pigment such as carbon black or iron black is added may be used. Among these, carbon black is preferable in terms of (black) color development, weather resistance, and other physical properties.
In addition, what is necessary is just to use well-known various grade resin as an ABS resin to be used according to a use. The thickness of the black ABS resin sheet is not particularly limited, but is usually about 100 to 300 μm in consideration of the total thickness required for the entire sheet for simultaneous injection molding and painting.
[0033]
[Others]
In addition, in order to laminate | stack each layer of the sheet | seat for injection molding simultaneous painting on the said structure, what is necessary is just as follows, for example in the case of a layer structure like FIG. 1 (A). A decorative sheet 2 is printed on the back surface of the transparent acrylic resin sheet 1, and subsequently a printed sheet is prepared by coating or printing the adhesive layer 3. On the other hand, the black ABS resin sheet 5 and the colored concealed ABS resin sheet 4 are prepared, and these ABS resin sheets are bonded to each other by a thermal fusion method or a dry lamination method using a urethane resin adhesive or the like between them. A laminated sheet is obtained by laminating. And what is necessary is just to laminate | stack the said printing sheet and this lamination sheet by the heat sealing | fusion of the adhesive bond layer of the said printing sheet. Note that the black ABS resin sheet and the colored concealed ABS resin sheet may be laminated simultaneously with the film formation by a two-layer coextrusion method.
[0034]
Injection molding simultaneous painting method:
The injection molding simultaneous painting method of the present invention uses the above-mentioned injection molding simultaneous painting sheet of the present invention, and laminates and integrates the painting sheet on the surface of the resin molding by the so-called injection molding simultaneous painting method, This is a method for obtaining a molded article with a picture painted with a sheet for painting.
[0035]
In addition, the injection molding simultaneous painting method means that the injection molding simultaneous painting sheet is disposed between both the male and female molds of injection molding as described in Japanese Patent Publication No. 50-19132, Japanese Patent Publication No. 43-27488, and the like. Thereafter, the resin in a fluid state is injected and filled into a mold, and simultaneously with the molding of the resin molded product, a sheet for simultaneous injection molding is laminated and painted on the surface.
[0036]
The injection molding simultaneous painting method of the present invention can take various forms in the conventionally known injection molding simultaneous painting method except that the above-described injection molding simultaneous painting sheet of the present invention is used as the painting sheet to be used. is there. For example, it may be either a form in which a picture sheet is preformed or not. In addition, the picture sheet may or may not be preheated. In the pre-molding, the picture sheet is usually preheated.
[0037]
Of course, when the drawing sheet has a large aperture, it is preferable to perform preforming. On the other hand, when the drawing sheet has a small aperture, the drawing sheet may be formed only by the resin pressure of the injected resin in a fluid state. At this time, if the aperture is shallow, the picture sheet may be molded with the resin pressure of the resin in a fluid state filled in the mold at the same time as the resin injection without preforming. Even when a sheet for painting is molded by resin pressure, the sheet for painting may sometimes use the heat of the injection resin without preheating. In addition, the preforming of a sheet for painting is usually performed by using an injection mold as a vacuum mold (in-line preforming), but before supplying the sheet for painting between molds, another vacuum is provided outside the mold. Pre-forming (off-line pre-forming) such as vacuum forming a picture sheet with a forming die may be used. However, the pre-molding is preferably carried out by using both the injection mold and the vacuum mold in that the sheet for painting can be efficiently and accurately laminated. However, in the case where pre-formed picture sheets are manufactured in advance in another place, the pre-form is preferably in the form of off-line pre-form. In the description of the present invention, vacuum forming includes vacuum / pressure forming.
The injection molding simultaneous painting sheet used in the injection molding simultaneous painting method of the present invention may of course be either a single sheet or a continuous strip.
[0038]
With reference to the conceptual diagram of FIG. 2, the injection molding simultaneous painting method of the present invention will be described in one form. In the form shown in FIG. 2, the injection molding simultaneous painting sheet is formed by heating and softening the injection molding simultaneous painting sheet in a vacuum molding mold which is a mold different from the injection molding mold, and then injecting the molded injection molding simultaneous painting sheet. This is a form by off-line pre-molding in which the resin is injected after being inserted into the mold. Next, the injection molding simultaneous painting method of this embodiment will be further described with reference to FIG.
[0039]
First, as shown in FIG. 2A, using a vacuum forming mold Mv having suction means such as suction holes 31 on the mold surface, a sheet for simultaneous injection-molding with heat softened by a heater 32 is preformed by vacuum forming. . In the drawing, the vacuum mold Mv is a mold surface having substantially the same shape and the same as that of an injection mold Mb described later. The vacuum forming die Mv is made of a metal such as iron or aluminum, or ceramics. Further, the injection-molded simultaneous painting sheet S is appropriately fixed by a frame-shaped sheet clamp 33. At this time, the back side (black ABS resin sheet side) of the injection-molded simultaneous painting sheet is oriented to the injection resin side (upward in the drawing). The heat softening by the heater 32 is, for example, non-contact radiation heating, but may be conductive heating by contact. In the preliminary molding, vacuum suction is performed by suction from the suction hole, and the picture sheet is vacuum molded along the mold surface of the vacuum mold Mv. Note that the vacuum forming may be vacuum / pressure forming using pressure air together, and includes this.
[0040]
Subsequently, the preformed injection-molded simultaneous painting sheet S is supplied between a pair of injection molds Ma and Mb as shown in FIG. Here, the injection mold Ma has a runner and a gate that communicate with the injection nozzle, and the injection mold Mb has a cavity surface that is the same or substantially the same as the mold surface of the preforming mold Mv. It has a shape and becomes a mold for fixing a preformed sheet for painting. These molds are made of metal such as iron or ceramics. In the mold open state, the painting sheet S is supplied between both molds Ma and Mb, and the painting sheet S is fixed to the mold Mb by pressing it with a frame-shaped sheet clamp 42. In this case, it is a matter of course that the back side (black ABS resin sheet side) of the injection-molded simultaneous painting sheet is the injection resin side on the right side of the drawing. Next, as shown in FIG. 2C, both molds are clamped, and a resin in a fluid state such as a heat-melted state is injected and filled into a cavity formed by both molds. And when there is an unnecessary part of the sheet for painting, if it is appropriately trimmed (cut), the sheet S for painting is laminated on the surface of the resin molded product 6 as conceptually shown in the sectional view of FIG. A molded article P with a picture is obtained.
[0041]
In the injection molding simultaneous painting method, as the injection molding resin which is injection molded into a resin molded product, conventionally known ones can be used, and basically there are no particular restrictions. What is necessary is just to select according to etc. However, in the present invention, since an ABS resin is used on the back side of the sheet for simultaneous injection molding, a styrenic resin having good adhesion to this is suitable. Examples of the styrenic resin include ABS resin, AS resin, and PS resin.
[0042]
Note that as the injection molding resin, a resin colored by adding a colorant may be used as appropriate according to the application. As the colorant, a known colorant as described in the decoration layer can be used. In addition, for injection molding resin, as necessary, inorganic powder such as silica, alumina, calcium carbonate, aluminum hydroxide, filler such as wood powder, glass fiber, stabilizer, lubricant, rubber (elastomer), etc. Various known additives are contained.
[0043]
FIG. 3 is a cross-sectional view illustrating the resulting molded article P with a picture, which is a molded article having a structure in which the injection-molded simultaneous painting sheet S of the present invention is laminated on the surface of the resin molded article 6. In FIG. 3, the layer configuration in the injection-molded simultaneous painting sheet S is omitted, but the configuration is as shown in FIGS. 1 (A) and 1 (B). The picture-formed molded product P can be used for various purposes such as vehicle interior materials, vehicle exterior materials, home appliances, office equipment cabinets, and miscellaneous goods.
[0044]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples.
[0045]
〔Example〕
An injection-molded simultaneous painting sheet S as shown in FIG. 1B was produced as follows. First, a dynamic friction coefficient with respect to a glass flat plate surface comprising polymethyl methacrylate (PMMA) as a main component and 0.2 mass% of an aliphatic alcohol lubricant and 0.4 mass% of a benzotriazole ultraviolet absorber added thereto. A colorless transparent acrylic resin sheet 1 having a thickness of 125 μm having a thickness of 0.45, a colored concealed ABS resin sheet 4 having a thickness of 100 μm, which is made by adding titanium white as a pigment and yellow lead to a petite, and carbon black And a black ABS resin sheet 5 having a thickness of 300 μm were prepared.
[0046]
Then, for the colored concealed ABS resin sheet 4, a 1 to 1 mass ratio mixture of vinyl chloride-vinyl acetate copolymer and acrylic resin is used as the binder resin, and the petal, yellow lead, phthalocyanine blue as the colorant And a wood grain decorative layer 2 formed by gravure printing with an ink using carbon black, and a thickness of 2 to 8 mass ratio of a vinyl chloride-vinyl acetate copolymer and an acrylic resin. A 2 μm thick adhesive layer 3 was formed on the entire surface by gravure printing to obtain a printed sheet.
[0047]
Then, the transparent acrylic resin sheet 1, the printed sheet, and the black ABS resin sheet 5 are stacked so that the printing surface of the printing sheet made of the colored concealed ABS resin sheet 4 faces the transparent acrylic resin sheet 1 side, Using a rotary roll plate press, the sheets were laminated by thermal fusion to obtain a sheet for simultaneous injection molding with the present invention.
[0048]
Furthermore, the injection molding simultaneous painting method adopting the offline pre-molding form as shown in the conceptual diagram of FIG. 2 and using the ABS resin as the injection molding resin, the above injection molding simultaneous painting sheet is resin molded. Simultaneously with the molding of the molded product on the surface of the product, the molded product P was obtained by laminating and integrating the sheet S for simultaneous injection molding with the resin molded product 6 as shown in FIG.
[0049]
As shown in FIG. 2A, the vacuum molding of the sheet for simultaneous injection molding has the same cavity surface as the female mold Mb for injection molding, but on the vacuum molding mold Mv separate from the female mold Mb. In addition, the heater 32 composed of an infrared radiation-type hot platen is heated and softened to 120 ° C. in a non-contact state with the injection-molded simultaneous painting sheet, and is vacuum-sucked from the suction holes 31 formed in the vacuum mold Mv. The preform was molded on the cavity surface of the mold Mv, cooled, and the preformed injection-molded simultaneous painting sheet was removed.
Then, as shown in FIG. 2 (B), this pre-molded injection-molded sheet with simultaneous painting is placed so that the back surface (black ABS resin sheet side) faces the male mold Ma side for injection molding. After being attached to the female mold Mb for injection molding at 42, both male and female molds are clamped as shown in FIG. 2 (C), and heated and melted at a nozzle temperature of 220 ° C. in a cavity formed by both male and female molds. After injection-filling ABS resin and solidifying by cooling, a molded article with a picture integrated with the picture sheet was formed, both the male and female molds were opened, and the picture-molded product was taken out.
[0050]
The resulting molded article with a picture had a high-class painting feeling, the cut end face was not easily noticeable, and the black color of the ABS resin sheet on the back side did not adversely affect the color of the pattern. Also, since no vinyl chloride resin sheet is used, it becomes an environmentally friendly product, and recycling of unnecessary injection-molded simultaneous painting sheets after trimming becomes easy.
[0051]
【The invention's effect】
{Circle around (1)} According to the sheet for simultaneous injection-molding of the present invention, although the cut end face is not noticeable, the color of the pattern is good. In addition, since the vinyl chloride resin sheet is not used, it is environmentally friendly and a paint feeling can be obtained. Moreover, the adhesion of each layer in the sheet for painting is good. Further, it is good in close contact with a resin molded product of styrene resin such as ABS resin, AS resin, PS resin or the like.
(2) According to the injection molding simultaneous painting method of the present invention, it is possible to obtain a molded product having a feeling of painting, the cut end face of the sheet for painting being inconspicuous, and having good pattern coloring. Since no vinyl resin sheet is used, it is easy to recycle the unnecessary injection-molded sheet with trimming after trimming, and the molded molded article can be made environmentally friendly.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of a form for simultaneous injection molding with a picture of the present invention.
FIG. 2 is a conceptual diagram illustrating an injection molding simultaneous painting method of the present invention in one form thereof.
FIG. 3 is a cross-sectional view illustrating a picture molded product obtained by the present invention.
[Explanation of symbols]
1 Transparent acrylic resin sheet
2 decoration layers
3 Adhesive layer
4 Colored concealed ABS resin sheet
5 Black ABS resin sheet
6 Resin molding
31 Suction hole
32 Heater
33 Sheet clamp
42 Sheet clamp
Ma injection mold (male mold)
Mb injection mold (female)
Mv vacuum mold
P Molded product with picture
S Sheet for simultaneous injection molding

Claims

In the laminate type injection molding sheet with simultaneous painting,
Adhesive layer made of a mixture of vinyl chloride-vinyl acetate copolymer and acrylic resin on the back side of the transparent acrylic resin sheet, using a binder resin as a mixture of vinyl chloride-vinyl acetate copolymer and acrylic resin A sheet for simultaneous injection-molding, in which an agent layer, a colored concealed ABS resin sheet containing at least titanium white, and a black ABS resin sheet containing at least carbon black are laminated in this order.

In the laminate type injection molding sheet with simultaneous painting,
An adhesive layer made of a mixture of vinyl chloride-vinyl acetate copolymer and acrylic resin was used on the back side of the transparent acrylic resin sheet, and a mixture of vinyl chloride-vinyl acetate copolymer and acrylic resin was used as the binder resin. A sheet for simultaneous injection-molding, wherein a decorative layer, a colored concealed ABS resin sheet containing at least titanium white, and a black ABS resin sheet containing at least carbon black are laminated in this order.

After the injection-molded simultaneous painting sheet according to claim 1 or 2 is disposed between a pair of molds, both molds are clamped, and a resin in a fluid state is injected and filled into a cavity formed by both molds. A method of simultaneous injection molding, in which a molded product is obtained by solidifying and molding a resin molded product and simultaneously integrating a sheet for injection molding on the surface thereof.