JP2004106445A

JP2004106445A - Sheet for injection molding with simultaneous decorating and method for injection molding with simultaneous decorating

Info

Publication number: JP2004106445A
Application number: JP2002274754A
Authority: JP
Inventors: Tamami Hirano; 平野　珠実
Original assignee: Dai Nippon Printing Co Ltd
Current assignee: Dai Nippon Printing Co Ltd
Priority date: 2002-09-20
Filing date: 2002-09-20
Publication date: 2004-04-08
Anticipated expiration: 2022-09-20
Also published as: JP4028337B2

Abstract

<P>PROBLEM TO BE SOLVED: To carry out a solid design expression without a disappearance of a concavo-convex pattern formed by embossing on a sheet by an injection molding with simultaneous decorating via a preliminarily forming a sheet. <P>SOLUTION: A sheet S for an injection molding with simultaneous decorating is composed of a first layer 1 as to be a surface side comprised of a crystalline resin such as a fluoro-resin or the like and a second layer 2 as an injection resin side comprised of a thermoplastic resin such as an acrylic resin or the like, and the concavo-convex pattern 4 is formed by an embossing process thrusted from the back side of the second layer to the surface side of the first layer, and the concavo-convex pattern comprises a concave part 4b at the back side of the second layer under a convex part 4a at the surface side of the first layer and further a decorating layer 3 or the like may be formed. The embossing process is carried out at a temperature of or above the melting point of the resin of the first layer and carrying out a preliminary forming of the sheet at a temperature lower than the melting point, the concavo-convex pattern can be kept without disappearance. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、射出成形同時加飾に使用される射出成形同時加飾用シートに関する。特に、シートの予備成形後、更には射出成形後に於いても、エンボス加工による凹凸模様が表面に残り、立体的な意匠表現が可能となる射出成形同時加飾用シートと射出成形同時加飾方法に関する。
【０００２】
【従来の技術】
樹脂成形物の表面に射出成形同時加飾用シートを積層一体化することで表面加飾された加飾成形品が各種用途で使用されている。この様な加飾成形品を得る代表的な方法として、いわゆる射出成形同時加飾方法（特許文献１、特許文献２等参照）がある。
【０００３】
また、シート表面に、木目導管溝等の立体的な凹凸模様を設ける場合には、一般的な化粧シートでは、熱圧によるエンボス加工が慣用的であり、射出成形同時加飾用シートに於いても、アクリルクリル樹脂シートに対して熱圧によるエンボス加工を施して凹凸模様を設ければ良いことが提案されている（特許文献３、参照）。
【０００４】
【特許文献１】
特公昭４３−２７４８８号公報
【特許文献２】
特公昭５０−１９１３２号公報
【特許文献３】
特開平１０−１２８７８９号公報（段落〔００２４〕、〔００２５〕）
【０００５】
【発明が解決しようとする課題】
しかしながら、アクリル樹脂シート等の通常の熱可塑性樹脂シートでは、凹凸模様を熱圧によるエンボス加工で設けても、射出成形同時加飾用シートの場合では、射出成形同時加飾用シートを予備成形する時の熱、或いは射出成形時の熱圧によって、エンボス形成された凹凸模様の凹凸形状が戻り易いという問題があった。
【０００６】
すなわち、本発明の課題は、射出成形同時加飾に於いて、シートの予備成形、更には射出成形後に於いても、シート表面に設けたエンボス加工による凹凸模様が消失しない様にして、立体的な凹凸感に基く意匠表現を可能にすることである。
【０００７】
【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加飾用シートでは、シートの予備成形を経た後、射出成形と同時に樹脂成形物表面にシートを一体化して加飾成形品を得る為の射出成形同時加飾用シートにおいて、射出成形同時加飾用シートは、結晶性樹脂からなり表側とする第一層と、熱可塑性樹脂からなり射出樹脂側とする第二層との少なくとも２層から構成され、且つ、第二層の裏側から第一層の表側まで突き抜けるエンボス加工による凹凸模様を有し、該凹凸模様は第一層表側の凸部に対して該凸部下方に位置する第二層裏側は凹部を成す、構成とした。
【０００８】
この様な構成とすることで、成形品となった段階で表面凹凸意匠を担う表側の第一層は結晶性樹脂としてあるので、その形状記憶（維持）性を利用でき、その結果、エンボス加工時はシート表面温度を該樹脂の融点以上になる様にすることで、該温度が低下すると該樹脂は再結晶化して凹凸模様の形状が固定される。しかも射出成形同時加飾時は、予備成形時のシート加熱温度を該樹脂の融点未満となる様にすることで結晶構造は維持され、凹凸模様の形状が維持される。しかも、その凹凸模様は、裏側凹部の上方の表側が凸部となる様に裏側から表側まで突き抜ける様なシート厚みに対して深い凹凸形状としてあるので、凹凸模様の形状はより一層維持し易くなる。従って、エンボス加工による凹凸模様がシートの予備成形工程後、更には射出成形工程後であっても、凹凸模様の形状が消失せず、成形品内部の他に成形品表面にも立体的な意匠表現ができる、射出成形同時加飾用シートとなる。
【０００９】
また、本発明の加飾成形用シートは、上記構成に於いて更に、第一層が少なくともフッ化ビニリデン樹脂を含み、第二層が少なくともアクリル系樹脂を含む構成とした。
この様な構成とすることにより、上記した本発明による効果を確実に得ることが出来る。
【００１０】
本発明の射出成形同時加飾方法は、射出成形同時加飾用シートの予備成形後、射出成形と同時に樹脂成形物表面に射出成形同時加飾用シートを一体化して加飾成形品を得る射出成形同時加飾方法において、（Ａ）射出成形同時加飾用シートとして、結晶性樹脂からなり表側とする第一層と、熱可塑性樹脂からなり射出樹脂側とする第二層との少なくとも２層からなる積層シートに対して、第一層の樹脂の融点以上の温度で、第二層の裏側から第一層の表側まで突き抜ける深さで熱圧によるエンボス加工を施すことで、第一層表側の凸部に対して該凸部下方に位置する第二層裏側は凹部を成す凹凸模様を形成して、射出成形同時加飾用シートを用意するシート作製工程、（Ｂ）上記射出成形同時加飾用シートを上記第一層の樹脂の融点未満の温度で真空成形により予備成形する予備成形工程、（Ｃ）予備成形された上記射出成形同時加飾用シートが射出成形型内に装填された状態で射出成形型内に樹脂を射出して、樹脂成形物の表面に射出成形同時加飾用シートを積層一体化する射出成形工程、の少なくとも各工程をこの順に行う、射出成形同時加飾方法とした。
【００１１】
この様な構成の射出成形同時加飾方法とすることで、凹凸模様のエンボス加工時は第一層の結晶性樹脂はその結晶構造が溶けて凹凸模様が賦形されるが、エンボス加工後、温度が低下すると該樹脂は再結晶化して凹凸模様の形状が固定され、しかも真空成形時のシート加熱は該融点未満の温度であるので、再結晶化した結晶構造は維持される、従って、凹凸模様の形状は保ち易くなる。この為、エンボス加工による凹凸模様がシートの予備成形工程後、更には射出成形工程後であっても、その凹凸模様の形状が消失しない様にして、立体的な意匠表現ができる射出成形同時加飾方法となる。
【００１２】
また、本発明の射出成形同時加飾方法は、上記加飾方法の構成に於いて、更に第一層が少なくともフッ化ビニリデン樹脂を含み、第二層が少なくともアクリル系樹脂を含む構成とした。
この様な構成とすることにより、上記した本発明による効果を確実に得ることが出来る。
【００１３】
【発明の実施の形態】
以下、図面を参照しながら本発明の実施の形態を説明する。
【００１４】
概要：
先ず、図１は、本発明による射出成形同時加飾用シートの一形態を主体に本発明を概念的に示す断面図である。図１（Ａ）は、エンボス加工前の段階の積層シート１０を示し、図１（Ｂ）はエンボス加工後に得られる本発明の射出成形同時加飾用シートＳを示す。そして、図１（Ｃ）は、図１（Ｂ）の射出成形同時加飾用シートＳを用いて射出成形同時加飾して得られる加飾成形品Ｐを示す。
【００１５】
図１に於いては、射出成形同時加飾用シートＳは、結晶性樹脂からなり表側となる第一層１と、熱可塑性樹脂からなり射出樹脂側となる第二層２と、該第二層２の更に裏側に印刷等で装飾層３を設けた構成の例である。
そして、図１（Ａ）の如き積層シート１０に対して、その裏側からエンボス加工を、表側が凸部となる程度まで施すことで、図１（Ｂ）の如き所望の凹凸模様４を有する射出成形同時加飾用シートＳが得られる。この際、凹凸模様４を賦形する為のエンボス加工は、第一層の結晶性樹脂の融点以上の温度で行うのが、凹凸模様の形状維持性能（形状記憶性）の点から好ましい。その結果、第二層２の裏側から第一層１の表側まで突き抜ける様なエンボス加工で、図１（Ｂ）の如く、凹凸模様４は、第一層１の表側の凸部４ａに対して、該凸部４ａの下方に位置する第二層２の裏側は凹部４ｂを成す様な凹凸模様が形成される。なお、表側まで突き抜けるとは言っても、表側に穴が開口してしまう様なエンボスでは無い。
【００１６】
そして、図１（Ｂ）に例示の如き射出成形同時加飾用シートＳを用いて、射出成形同時加飾すれば、その際の予備成形時（シート加熱は第一層の結晶性樹脂の融点未満の温度とする）、及び射出成形時に該シートが受ける熱、或いは熱圧で凹凸模様が消失せずに、成形品表面に凹凸模様４を有する、図１（Ｃ）に例示の如き樹脂成形物５の表面に射出成形同時加飾用シートＳが積層一体化した構成の加飾成形品Ｐが得られる。また、該加飾成形品Ｐには、成形品内部にも凹凸模様を有するものとなる。
【００１７】
なお、第一層１と第二層２の樹脂の組合わせの具体例として、第一層１の結晶性樹脂はフッ化ビニリデン樹脂であり、第二層の熱可塑性樹脂はアクリル系樹脂である。
【００１８】
射出成形同時加飾用シート：
以下、射出成形同時加飾用シートの各層から順に説明する。
【００１９】
〔第一層〕
第一層１は、射出成形同時加飾用シートを樹脂成形物に積層一体化させて出来る加飾成形品の状態において外側となる表側に位置させる層である。本発明ではこの第一層に結晶性樹脂を用いることによって、真空成形による予備成形を経る射出成形同時加飾で加飾成形品となった後でも、成形品表面に凹凸模様の凹凸形状が残る様な形状記憶性が得られる。なお、この為には、凹凸模様賦形の為のエンボス加工は、第一層の樹脂の融点以上の温度で行うと良い。そして、真空成形時のシート加熱は、該融点未満の温度で行うと良い。なお、第一層が非結晶性樹脂の場合では、融点未満のシート加熱温度で真空成形を行っても、樹脂が軟化し易く、凹凸模様の形状維持性能が悪い。
【００２０】
ところで、一般的に射出成形同時加飾では、射出成形同時加飾用シートを予備成形する為の真空成形（本発明の説明ではこれに真空圧空成形も包含する）に於いて、シート加熱温度は、真空成形型を射出成形型と兼用して射出成形型上で行うインライン予備成形の場合は１００〜１２０℃程度であり、真空成形を射出成形型とは別型、つまり射出成形機の外で専用の真空成形型で予め行うオフライン予備成形の場合には１４０〜１７０℃である。
従って、これらの観点から第一層の樹脂を選定するならば、第一層の結晶性樹脂としては、その融点がシート加熱温度以上となる温度のものを選定すれば良い。よって、第一層の結晶性樹脂の融点が、インライン予備成形に限定するならば１２０℃以上、好ましくは１３０℃以上、オフライン予備成形も含めて考えるならば１５０℃以上、乃至は１７０℃以上となる樹脂を選定することが好ましい。
【００２１】
上記の様な結晶性樹脂は、基本的には、用途、それに応じたシート成形形態（例えばインライン予備成形とオフライン予備成形）等に応じて、適宜選択すれば良い。この様な結晶性樹脂としては、例えばフッ素系樹脂等は好適な樹脂である。フッ素系樹脂としては、例えば、フッ化ビニリデン樹脂が挙げられ、フッ化ビニリデン樹脂では、樹脂組成にもよるが、例えば融点１６０℃以上の樹脂として利用できる。また、フッ化ビニリデン樹脂以外の結晶性樹脂となるフッ素系樹脂としては、例えばポリ４フッ化エチレン等が挙げられる。フッ化ビニリデン樹脂は、フッ素系樹脂のなかでもコスト的にも高すぎ、且つ適度な融点等の観点から優れている。なお、フッ素系樹脂以外の結晶性樹脂としては、例えば、ポリプロピレン、ナイロン等が挙げられる。
【００２２】
なお、第一層の厚みは、目的とする凹凸模様の深さ（裏側から突出した表側の凸部による凹凸模様であるので直感的には「高さ」である）、形状維持度合いに応じたものとすれば良い。一方、射出成形同時加飾用シート全体としての真空成形性は、第二層の方が主体的となって担わせる。従って、通常は、第一層の厚みは第二層の厚みよりも薄くする。例えば、第一層の厚みは第二層の厚みの１／２０〜２／８程度である。第一層の厚みの具体例を挙げれば、第二層の厚みにもよるが、５〜５０μｍ程度である。
【００２３】
〔第二層〕
第二層２は、通常、第一層よりも主体的に射出成形同時加飾用シートとしての総厚を主体的に担う層とするものである他、真空成形性を主体的に担わせる層でもある。この為、第二層には、真空成形性が良い樹脂として熱可塑性樹脂を用いる。また、第一層の融点未満の温度で射出成形同時加飾用シートを真空成形できる成形性を備えた樹脂を用いる。この様な熱可塑性樹脂としては、例えば、ポリプロピレン等のポリオレフィン系樹脂、アクリル系樹脂、塩化ビニル樹脂等を用いれば良い。なかでも、アクリル系樹脂は、シート加熱時の成形適性温度範囲を広くできる傾向があり好ましい。また、アクリル系樹脂は耐候性や透明性に優れている点でも好ましい。また、アクリル系樹脂は、第一層にフッ化ビニリデン樹脂を用い場合に、凹凸模様の形状維持性能（形状記憶性）、及び真空成形性等の点からも、好適な組合わせ樹脂である。
【００２４】
なお、アクリル系樹脂としては、例えば、ポリメチル（メタ）アクリレート、ポリエチル（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、エチル（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種以上の混合物で用いる。
【００２５】
なお、第二層の厚みは、シートの真空成形性の点で、第一層の厚みよりも厚くするのが好ましく、また、その具体的な厚み例を挙げれば５０〜２００μｍ程度である。
【００２６】
ところで、第一層と第二層との積層は、これら各層を樹脂シートとして用意し、両樹脂シートを接着剤を介して積層しても良いが、生産性、コスト等の点で、より好ましくは、両樹脂の２層共押出しによる溶融積層、或いは一方は樹脂シートとして用意し、これに溶融押出塗工するのが好ましい。２層共押出し或いは溶融押出塗工では、樹脂シートとしては不可能な薄い樹脂層でも形成できる利点がある。なかでも、２層共押出しは積層シートの層間密着性の点でより好ましい。
【００２７】
〔凹凸模様〕
本発明の凹凸模様４は、少なくとも第一層と第二層とを積層した積層シート１０〔図１（Ａ）参照〕に対して、第二層２の裏側から第一層１の表側まで突き抜けるエンボス加工によって形成したものである。この結果、該凹凸模様は、図１（Ｂ）で概念的に示す如く、第一層１表側の凸部４ａに対して該凸部４ａの下方に位置する第二層２の裏側には、該凸部４ａに対応した凹部４ｂを有する凹凸模様となる。
なお、「突き抜ける」とは、第一層の表側に穴が開口してしまう様なエンボスでは無く、第一層の表側面に凸部が出来る様なエンボスである。従って、第二層の裏側面から見た凹部の先端（谷底）が、シート厚み方向で第一層の内部まで必ず到達している事〔図１（Ｂ）ではそう描いてある。〕を意味するものでは無い。また、図１（Ｂ）では、凹部の先端部分では、第二層の厚みはゼロとして描いてあるが、有限の厚みを持っていても良い。
【００２８】
凹凸模様４は、本発明では熱圧を利用するいわゆるエンボス加工によって行う。エンボス加工は、従来公知の熱プレス方式の枚葉又は輪転式エンボス機を用いて、加熱軟化させた樹脂シートの表面にエンボス版を押圧して形成すれば良い。なお、エンボス加工の際、エンボス版の圧を受ける方は柔軟な表面の物（ゴム等）、具体的には輪転式であれば表面を柔軟なゴムで被覆した圧胴とすることによって、第一層の表側が凸部となって膨らむ様な深いエンボス加工を施すことができる。
【００２９】
ところで、一般に、成形品表面に凹凸模様を賦形する場合、その為の加飾用シートとしては、表側に対して該表側からエンボス加工したものを用いれば良いと考えるのが普通である。しかしながら、それとは逆に、裏側からエンボス加工し、それも表側に突き出る様にエンボス加工することで、表側に目的とする凹凸模様を設けたのが、今回の射出成形同時加飾用シートである。この結果、副次的に裏側にも凹凸模様ができるが、それは成形品内部の凹凸模様として生かす事もできる。一方、最終的に同じ深さ（高さ）の凹凸模様となるエンボス加工であっても、慣用的な表側からのエンボス加工による場合では、成形品内部の凹凸模様が得られないため、本発明による様な、内部凹凸模様による凹凸感も加わった豊かな立体的意匠効果は得られない。
【００３０】
凹凸模様を賦形する為のエンボス加工の温度、つまり賦形対象とする積層シートの加熱温度は、シート温度（より厳密には第一層側のシート表面温度で）、好ましくは、第一層の結晶性樹脂の融点以上の温度とすると良い。それは、前述した如く、該融点以上の温度でエンボス加工することで、第一層の結晶性樹脂はその結晶構造が溶けて凹凸模様が確実に賦形され、且つ、エンボス加工後に於いては、加熱された第一層の温度が低下するにつれて第一層の該樹脂は再結晶化して凹凸模様の形状が固定されるという形状保持性能（形状記憶性）が得られるからである。
なお、この様なエンボス加工の温度は、樹脂にもよるが通常は１６０〜１９０℃程度である。
【００３１】
凹凸模様の模様としては、要求される意匠表現に応じたものとすれば良く、特に限定されるものではない。例えば、梨地、砂目、砂紋、地紋、万線状溝、木目年輪模様、木目導管溝、花崗岩の劈開面の凹凸模様、布目の表面テクスチュア、皮絞、文字、幾何学模様等である。
【００３２】
なお、凹凸模様の模様としては特に制限は無いが、そのサイズに於いては、シート表面に突き抜けて形成された該表面の凹凸形状があまりに小さいと、真空成形時、或いは射出成形時の熱或いは熱圧により凹凸形状が消失し易くなる。凹凸形状が鈍ったとしても、加飾成形品に於いて凹凸模様と認識できる程度に形状維持ができる程度の望ましい凹凸形状のサイズは、第一層及び第二層の樹脂内容やそれら各層の厚み、予備成形条件、射出成形条件等にもよるが、例えば、第一層に厚み８μｍのフッ化ビニリデン樹脂、第二層に厚み７２μｍのアクリル系樹脂を用い場合では、射出成形同時加飾用シートに於ける表側面（第一層の表面）の凹凸を成す凸部４ａの高さ（表側高低差）Ｈが３０μｍ以上とすると良い結果が得られる。すなわち、射出成形同時加飾の工程中に凹凸形状がと鈍っても、成形品となった段階で凹凸感が感じられる程度にまで凹凸形状を残すことができた（表１参照）。
【００３３】
ここで、図２の概念的な断面図で、上記した高さＨを含む凹凸模様４のサイズの意味を示す。なお、図２では、第一層と第二層は区別せず、これらが積層された状態の射出成形同時加飾用シートＳとして描いてある。また、凸部４ａに対して、その下方のシート裏側には深さ（裏側高低差）Ｄの凹部４ｂを有する。該凹部４ｂの開口部の幅が間口Ｌである。
【００３４】
なお、シート裏側の凹部４ｂの深さＤと間口Ｌについては、前述した高さＨ３０μｍ以上の条件に於いて、深さＤは５０μｍ以上、間口Ｌは５００μｍ以上であった。一般に、裏側の凹部の深さＤが小さすぎると、表側の凸部の高さＨが十分に得られず、また、裏側の凹部の間口Ｌが小さすぎても、表側に十分な凸部を設けることができず、成形品までの凹凸形状の形状維持性能を十分に得ることができなくなる。
【００３５】
〔装飾層〕
本発明による射出成形同時加飾用シートは、凹凸模様による意匠を必須構成要件として有する点からも、層的には第一層と第二層のみでも良いが、通常は図１に例示の如く、より高意匠に出来る等の点で、更に装飾層３を設けるのが好ましい。
【００３６】
装飾層３は絵柄表現等の意匠性、或いはその他の加飾目的の為に設ける層であり、装飾層が無くても凹凸模様により相応の意匠性等は付与できるが、より意匠性等を向上させる為に通常は設けられる。装飾層を設ける位置は、第一層と第二層との間、任意であるが、耐久性や塗装感等の点では第二層の裏側面に設けるのが好ましい。この場合、通常、第一層と第二層とを積層した積層シートに、その裏側面に装飾層を形成する。
装飾層の形成は、グラビア印刷、活版印刷、シルクスクリーン印刷、オフセット印刷、インクジェット印刷等の公知の印刷法で形成すれば良い。また、全面ベタ柄の場合は、ロールコート等の公知の塗工法でも良い。なお、使用するインキ（或いは塗液）も、第一層の樹脂に応じたものを適宜選択すれば良い。
【００３７】
装飾層の形成に使用するインキ（或いは塗液）としては、接着性等を考慮して公知のものの中から適宜選択使用すれば良い。例えば、インキ（或いは塗液）のバインダーの樹脂としては、アクリル樹脂、塩化ビニル−酢酸ビニル共重合体、ポリエステル樹脂、ポリウレタン樹脂等を用いる。また、インキ（或いは塗液）に含有させる着色剤としては、例えば、チタン白、亜鉛華、カーボンブラック、鉄黒、弁柄、カドミウムレッド、群青、コバルトブルー、黄鉛、チタンイエロー等の無機顔料、フタロシアニンブルー、インダスレンブルー、イソインドリノンイエロー、キナクリドンレッド、ペリレンレッド等の有機顔料、アルミニウム、真鍮等の金属の粉末又は鱗片等の金属顔料、二酸化チタン被覆雲母の粉末又は鱗片等の真珠光沢（パール）顔料、或いは染料等が用いられる。
【００３８】
なお、装飾層の絵柄は、例えば、梨地模様、砂目模様、砂紋模様、地紋模様、万線状模様、木目模様、石目模様、布目模様、皮絞模様、タイル貼模様、煉瓦積模様、幾何学図形、文字、記号、或いは全面ベタ等である。
【００３９】
また、装飾層３としては、例えばアルミニウム、クロム等を蒸着して全面或いは部分的に形成した金属薄膜層等でも良い。
なお、本発明に於いて、装飾層としては、木目等の意匠表現以外に、磁性体層、導電性層等の機能性層等による機能性付与でも良い。つまり、本発明に於いて、装飾、乃至は加飾とは、この様な機能性付与も包含する。
【００４０】
〔その他の構成層〕
本発明の射出成形同時加飾用シートは、必要に応じ適宜、上記装飾層以外の層を設けても良い。例えば、層間密着力を強化するプライマー層、射出樹脂との密着性を強化する為に裏面側に設ける接着剤層等である。
また、射出成形同時加飾用シートの裏側面には、必要に応じ適宜、被着体である樹脂成形物との接着性を向上させるために、コロナ放電処理、プラズマ処理、プライマー塗工等の易接着処理を施しても良い。
【００４１】
なお、接着剤層としては、感熱型の接着剤として熱可塑性樹脂、熱硬化性樹脂等の公知の樹脂が用いられる。熱可塑性樹脂では、例えば、アクリル樹脂、塩素化ポリオレフィン樹脂、塩化ビニル−酢酸ビニル共重合体、熱可塑性ウレタン樹脂、熱可塑性ポリエステル樹脂、ポリアミド樹脂、ゴム系樹脂等の１種又は２種以上の混合物が用いられる。また、熱硬化性樹脂では、ウレタン樹脂、エポキシ樹脂等が用いられる。
【００４２】
射出成形同時加飾方法：
次に、本発明による射出成形同時加飾方法では、いわゆる射出成形同時加飾方法に対して、それに用いる射出成形同時加飾用シートのシート作製工程（シート材料及び方法）を特定の工程とし、且つ、該シートの予備成形としての真空成形工程も特定の工程とした加飾方法である。以下、本射出成形同時加飾方法について、シート作製工程、予備成形工程、射出成形工程の順に説明する。
【００４３】
〔シート作製工程〕
シート作製工程は、前述した如き射出成形同時加飾用シートを作製して用意する工程である。従って、本発明によるシート作製工程では、射出成形同時加飾用シートの層及びその樹脂組成、また凹凸模様のエンボス加工方法及び加工温度等を特定したシート作製工程となる。つまり、シート作製工程では、射出成形同時加飾用シートとして、結晶性樹脂からなり表側とする第一層と、熱可塑性樹脂からなり射出樹脂側とする第二層との少なくとも２層からなる積層シートに対して、第一層の樹脂の融点以上の温度で、第二層の裏側から第一層の表側まで突き抜ける深さで熱圧によるエンボス加工を施して、第一層表側の凸部に対して該凸部下方に位置する第二層裏側は凹部を成す凹凸模様を形成して、射出成形同時加飾用シートを用意する。なお、該射出成形同時加飾用シートの好適な具体例を挙げれば、前述した如く、第一層がフッ化ビニリデン樹脂からなり、第二層がアクリル系樹脂からなる構成である。
【００４４】
〔予備成形工程〕
本発明では、以上の如き射出成形同時加飾用シートを用いて、シート予備成形有りの形態で射出成形同時加飾する際に、該シート予備成形時のシート加熱は、シート加熱温度を、射出成形同時加飾用シートの第一層の結晶性樹脂が呈する融点未満の温度として行う。これによって、シート予備成形時の成形性を確保すると共に、予備成形後の凹凸模様の形状維持もできる様になる。
【００４５】
なお、射出成形同時加飾用シートを予備成形する為の真空成形（真空圧空成形も包含する）は、大別して、真空成形型を射出成形型と兼用して該射出成形型上で真空成形を行うインライン予備成形の形態と、真空成形型は射出成形型とは別型で、つまり射出成形機の外で真空成形を行うオフライン予備成形の形態のどちらでも良い。
【００４６】
〔射出成形工程〕
射出成形工程では、上記の如き予備成形工程によって予備成形された射出成形同時加飾用シートを、射出成形型内に装填された状態で、雌雄一対の射出成形型を型締めした後、射出成形型のキャビティ内に樹脂を射出し充填して固化させて、樹脂成形物の表面に射出成形同時加飾用シートを積層一体化する工程である。そして、樹脂固化後、型開きして、目的とする加飾成形品を取出す。該加飾成形品には、前述如き射出成形同時加飾用シートによって、成形品表面（及び内部にも）に立体的な凹凸模様が付与される。
【００４７】
〔射出樹脂〕
なお、樹脂成形物となる射出樹脂としては、基本的には特に制限はなく公知の樹脂で良い。製品の要求物性やコスト等に応じて選定すれば良い。熱可塑性樹脂であれば、ＡＢＳ（アクリロニトリル−ブタジエン−スチレン共重合体）樹脂、スチレン樹脂、アクリル樹脂、塩化ビニル樹脂、ポリカーボネート樹脂、ポリオレフィン系樹脂等である。また、硬化性樹脂であれば、２液硬化型の樹脂、例えば、ウレタン樹脂、不飽和ポリエステル樹脂、エポキシ樹脂等の未硬化樹脂液等である。熱可塑性樹脂は加熱熔融して流動状態で射出し、また硬化性樹脂は（その未硬化物を）室温又は適宜加熱して流動状態で射出する。
なお、射出樹脂は、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、前述基材シートで述べた如き公知の着色剤を使用すれば良い。また、射出樹脂には、必要に応じ適宜、シリカ、アルミナ、タルク、炭酸カルシウム、水酸化アルミニウム等の無機物粉末、ガラス繊維等の充填剤、安定剤、滑剤等の公知の各種添加剤を含有させる。
【００４８】
〔成形品形状〕
なお、加飾成形品の形状は、シート積層面は凹凸面等の非平面、或いは平面の立体物である。また、加飾成形品の形状は、板状（平板、曲面板等）、柱状、三次元立体物等と任意である。
【００４９】
〔その他〕
ここで、図３の概念図を用いて、いわゆる射出成形同時加飾方法について、概説しておく。なお、ここで説明する形態は、射出成形型上で予備成形工程を行うインライン予備成形の形態である。
【００５０】
先ず、図３（Ａ）の如く、射出成形型としては、射出ノズルと連通する湯道（ランナー）及び湯口（ゲート）を有する型Ｍａと、キャビティ面に吸引孔４１を有し射出成形同時加飾用シートの予備成形工程用の真空成形型を兼用する型Ｍｂの一対の成形型を用いる。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間に射出成形同時加飾用シートＳを供給し、型Ｍｂに射出成形同時加飾用シートＳを平面視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、射出成形同時加飾用シートの第二層側の裏側は、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３（Ｂ）の如く、型外部（図面では型上方）の退避位置で退避させておいたヒータ４３を、適宜移動させて両型間に挿入し、ヒータ４３で射出成形同時加飾用シートを加熱軟化させる。加熱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、吸引孔から吸引して真空成形して、射出成形同時加飾用シートを型Ｍｂのキャビティ面に沿わせ予備成形する。次いで、ヒータを両型間から退避させ、図３（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充填する。そして、樹脂が冷却等によって固化した後、型開きして成形物を取り出す。
射出成形同時加飾用シートの不要部分は適宜トリミングすれば、図１（Ｃ）の如く、樹脂成形物５に射出成形同時加飾用シートＳが積層され加飾された加飾成形品Ｐが得られるという方法である。
そして、本発明では、この射出成形同時加飾用シートによって凹凸模様４が加飾成形品の表面（及び内部）に付与され、立体的な意匠表現が可能となる。
【００５１】
【実施例】
以下、実施例により本発明を更に詳述する。
【００５２】
〔実施例１〕
図１（Ｂ）で例示の如き射出成形同時加飾用シートＳを次の様にして作製した。先ず、フッ化ビニリデン樹脂からなる第一層１（厚み８μｍ）とアクリル系樹脂からなる第二層２（厚み７２μｍ）とが積層された透明な積層シートを用意した。なお、この積層シートは２層共押出法で作製されたものである。そして、この積層シートの第二層側の面に、アクリル系樹脂を含むインキによるグラビア印刷で柄模様を意匠表現した装飾層３を形成して、図１（Ａ）の如き構成の積層シート１０を作製した。
【００５３】
次に、上記積層シート１０の第二層２（装飾層３）側の面から、エンボス加工を施して、ドット模様の凹凸模様４を形成して、図１（Ｂ）の如き射出成形同時加飾用シートＳを作製した。エンボス加工の際の、エンボス圧力は０．６Ｐａ（６ｋｇｆ／ｃｍ^２）、エンボス速度は５ｍ／ｍｉｎ、シート表側のシート表面温度は、上記フッ化ビニリデン樹脂の融点と同じ１６０℃とした。また、用いエンボス版の版深は８０μｍである。
【００５４】
次に、上記射出成形同時加飾用シートＳを、射出成形型を真空成形型と兼用するインライン予備成形の形態で射出成形同時加飾を行った。すなわち、射出成形と同時に成形品表面にシートを一体的に接着できる様にした射出成形同時加飾装置（シート供給機構、予備成形機構等を備える）を設置した射出成形機を用いて、その射出成形金型の雄型と雌型との間に、射出成形同時加飾用シートを、第二層側がノズルを有する雄型側を向く様にして供給して、射出成形同時加飾を行った。
なお、射出樹脂にはＡＢＳ樹脂を使用し、予備成形はシート温度が最大９０℃となる様に射出成形同時加飾用シートを加熱軟化して行った。なお、金型温度は６０℃、射出樹脂温度は２３５℃とした。
【００５５】
得られた加飾成形品の表面に付与された凹凸模様は、その凹凸の高さ（高低差）が６．４μｍであった。また、成形品内部にも、シート裏面側の凹凸に基く凹凸模様が見られた。これにより、加飾成形品には、成形品内部だけでなく、成形品表面にも立体的な凹凸感を付与できる事が判明し、良好な結果が得られた。
【００５６】
なお、表１に、評価結果と、凹凸模様のサイズ（射出成形同時加飾用シートの状態及び加飾成形品の状態）とを、他の試験例と共に纏めて示す。
ちなみに、本実施例１では、凹凸模様のサイズは、射出成形同時加飾用シートの状態で、表側凹凸の高さは４７μｍ、裏側凹凸の深さは８６μｍ、裏側凹凸の開口部の間口は５３６μｍであり、成形品表面の凹凸高さは６．４μｍであった。
【００５７】
〔実施例２〕
実施例１に於いて、凹凸模様を砂紋（疎）に変更した以外は、実施例１と同様にして射出成形同時加飾用シートを作製した。そして、この射出成形同時加飾用シートを用いて、実施例１と同様にして加飾成形品を作製した。結果は、表１に示す如く、最終的に成形品表面の凹凸高さ５．０μｍが得られて、凹凸感が感じられ良好であった。
【００５８】
〔実施例３〕
実施例１に於いて、凹凸模様を砂紋（密）（実施例２よりも密な砂紋）に変更した以外は、実施例１と同様にして射出成形同時加飾用シートを作製した。そして、この射出成形同時加飾用シートを用いて、実施例１と同様にして加飾成形品を作製した。結果は、表１に示す如く、最終的に成形品表面の凹凸高さ４．０μｍが得られて、凹凸感が感じられ良好であった。
【００５９】
〔実施例４〕
実施例１に於いて、凹凸模様を梨地模様に変更した以外は、実施例１と同様にして射出成形同時加飾用シートを作製した。そして、この射出成形同時加飾用シートを用いて、実施例１と同様にして加飾成形品を作製した。結果は、表１に示す如く、最終的に成形品表面の凹凸高さ５．１μｍが得られて、凹凸感が感じられ良好であった。
【００６０】
〔参考例１〕
参考までに、凹凸模様のサイズが小さすぎて不十分となった場合の実験例を挙げる。
実施例１に於いて、凹凸模様を木目模様Ａに変更した以外は、実施例１と同様にして射出成形同時加飾用シートを作製した。そして、この射出成形同時加飾用シートを用いて、実施例１と同様にして加飾成形品を作製した。しかし、結果は、表１に示す如く、射出成形同時加飾用シートの状態における凹凸模様のサイズが不十分で（表側凹凸の高さ１６μｍ、裏側凹凸深さ１７μｍ、裏側凹凸間口２３８μｍ）、加飾成形品では成形品表面の凹凸高さ０．６μｍしか得られず、凹凸感が感じられなかった。
【００６１】
〔参考例２〕
実施例１に於いて、凹凸模様を木目模様Ｂ（参考例１とは違う木目模様）に変更した以外は、実施例１と同様にして射出成形同時加飾用シートを作製した。そして、この射出成形同時加飾用シートを用いて、実施例１と同様にして加飾成形品を作製した。しかし、結果は、表１に示す如く、射出成形同時加飾用シートの状態における凹凸模様のサイズが不十分で（表側凹凸の高さ３０μｍ、裏側凹凸深さ２５μｍ、裏側凹凸間口２５３μｍ）、加飾成形品では成形品表面の凹凸高さ０．６μｍしか得られず、凹凸感がは感じられなかった。
【００６２】
〔比較例１〕
実施例１に於いて、第一層と第二層とを積層した積層シートの代わりに、厚さ８０μｍの単層のアクリル系樹脂シートを用いて、装飾層を裏側とする面に形成して積層シートを作製した。そして、この積層シートに裏側からエンボス加工を行い、射出成形同時加飾用シートを作製した。そして、実施例１と同様の射出成形同時加飾方法によって加飾成形品の作製を試みた。なお、エンボス時のシート加熱温度は１６０℃、予備成形時のシート加熱温度は１００℃とした。その結果、予備成形後の段階でシート表面の凹凸模様は消失してしまった。
【００６３】
【表１】

【００６４】
【発明の効果】
（１）本発明の射出成形同時加飾用シートによれば、エンボス加工による凹凸模様が予備成形工程後、更には射出成形工程後の加飾成形品の状態であっても、凹凸模様の形状が消失せず、成形品内部の他に成形品表面にも立体的な凹凸感を付与できる。
なお、表側の第一層にフッ化ビニリデン樹脂を用い、その裏側の第二層にアクリル系樹脂を用いれば、上記効果をより確実に得ることが出来る。
【００６５】
（２）本発明の射出成形同時加飾方法によれぱ、使用する射出成形同時加飾用シート上でのエンボス加工による凹凸模様の凹凸形状が、射出成形同時加飾時に消失しない様にして、成形品内部の他に成形品表面にも立体的な凹凸感を付与した加飾成形品が得られる。
なお、使用する射出成形同時加飾用シートとして、表側の第一層にフッ化ビニリデン樹脂を用い、その裏側の第二層にアクリル系樹脂を用いたシートを用いれば、上記効果をより確実に得ることが出来る。
【図面の簡単な説明】
【図１】本発明による射出成形同時加飾用シートと加飾成形品の例示する断面図。
【図２】本発明による凹凸模様の形状を概念的に説明する断面図。
【図３】本発明で利用する射出成形同時加飾方法をその一形態で説明する概念図。
【符号の説明】
１　　第一層
２　　第二層
３　　装飾層
４　　凹凸模様
４ａ　（表側の）凸部
４ｂ　（裏側の）凹部
５　　樹脂成形物
１０　積層シート
４１　吸引孔
４２　シートクランプ
４３　ヒータ
Ｄ　　（凹部）の深さ
Ｈ　　（凸部）の高さ
Ｌ　　（凹部）の間口
Ｍａ　射出成形型（雄型）
Ｍｂ　射出成形型（雌型）
Ｐ　　加飾成形品
Ｓ　　射出成形同時加飾用シート[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a sheet for simultaneous injection-molding and decorating used for simultaneous injection-molding and decorating. In particular, even after the preforming of the sheet and even after the injection molding, the embossed pattern remains on the surface, and the sheet for simultaneous simultaneous injection molding decoration and the method for simultaneous injection molding decoration that enables three-dimensional design expression. About.
[0002]
[Prior art]
2. Description of the Related Art Decorative molded products whose surfaces are decorated by laminating and integrating a sheet for simultaneous injection molding decoration on the surface of a resin molded product are used for various purposes. As a typical method for obtaining such a decorative molded product, there is a so-called simultaneous injection molding decorative method (see Patent Document 1, Patent Document 2, etc.).
[0003]
In addition, when a three-dimensional uneven pattern such as a wood grain conduit groove is provided on the sheet surface, embossing by hot pressure is customary in a general decorative sheet, and in a sheet for simultaneous decoration by injection molding, It has also been proposed that an acrylic acryl resin sheet be embossed by heat and pressure to provide an uneven pattern (see Patent Document 3).
[0004]
[Patent Document 1]
JP-B-43-27488
[Patent Document 2]
Japanese Patent Publication No. 50-19132
[Patent Document 3]
JP-A-10-128789 (paragraphs [0024] and [0025])
[0005]
[Problems to be solved by the invention]
However, in the case of a normal thermoplastic resin sheet such as an acrylic resin sheet, even if the concavo-convex pattern is provided by embossing by hot pressure, in the case of the sheet for simultaneous injection molding decoration, the sheet for simultaneous injection molding decoration is preformed. There has been a problem that the uneven shape of the embossed uneven pattern tends to return due to heat at the time or heat and pressure during injection molding.
[0006]
That is, an object of the present invention is to provide a three-dimensional object by performing pre-molding of a sheet in simultaneous decoration by injection molding, and even after injection molding, so that the embossed pattern provided on the sheet surface does not disappear. The purpose is to enable a design expression based on a sense of unevenness.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, in order to obtain a decorative molded product, the sheet for simultaneous injection molding and decorating of the present invention, after the sheet is preformed, is integrated with the surface of the resin molded product simultaneously with the injection molding. In the sheet for simultaneous decorating by injection molding, the sheet for simultaneous decorating by injection molding has at least two layers of a first layer made of a crystalline resin and serving as a front side, and a second layer made of a thermoplastic resin and serving as an injection resin side. And has an uneven pattern by embossing that penetrates from the back side of the second layer to the front side of the first layer, and the uneven pattern is located below the convex portion on the first layer front side. The back side of the two layers forms a concave portion.
[0008]
By adopting such a configuration, the first layer on the front side, which carries the surface irregularity design at the stage of forming a molded product, is made of a crystalline resin, so that its shape memory (maintenance) property can be used, and as a result, embossing At this time, the sheet surface temperature is set to be equal to or higher than the melting point of the resin, and when the temperature decreases, the resin is recrystallized and the shape of the uneven pattern is fixed. In addition, at the time of decorating simultaneously with injection molding, by setting the sheet heating temperature at the time of preliminary molding to be lower than the melting point of the resin, the crystal structure is maintained, and the shape of the concavo-convex pattern is maintained. In addition, since the uneven pattern has a deep uneven shape with respect to the sheet thickness such that the front side above the rear concave part becomes a convex part from the back side to the front side, the shape of the uneven pattern is more easily maintained. . Therefore, even after the pre-forming step of the sheet and after the injection molding step, the uneven pattern by the embossing process does not lose the shape of the uneven pattern, and the three-dimensional design is formed not only inside the molded article but also on the surface of the molded article. It becomes a sheet for simultaneous decoration by injection molding that can be expressed.
[0009]
In the decorative molding sheet of the present invention, the first layer further includes at least a vinylidene fluoride resin, and the second layer includes at least an acrylic resin.
With such a configuration, the effects of the present invention described above can be reliably obtained.
[0010]
The injection molding simultaneous decorating method of the present invention is an injection molding method in which after the injection molding simultaneous decorating sheet is preformed, the injection molding simultaneous decorating sheet is integrated with the resin molded product surface simultaneously with the injection molding to obtain a decorative molded product. In the simultaneous molding and decorating method, (A) at least two layers of a first layer made of a crystalline resin and serving as a front side, and a second layer made of a thermoplastic resin and serving as an injection resin side, as the sheet for simultaneous injection molding and decorating The laminated sheet consisting of the first layer at a temperature equal to or higher than the melting point of the resin of the first layer, by embossing by hot pressure at a depth penetrating from the back side of the second layer to the front side of the first layer, the front side of the first layer A sheet forming step of forming a concave and convex pattern forming a concave portion on the back side of the second layer located below the convex portion with respect to the convex portion, and preparing a sheet for simultaneous decoration by injection molding; The decorative sheet is heated to a temperature lower than the melting point of the resin of the first layer. (C) Injecting the resin into the injection mold while the preformed sheet for simultaneous injection molding and decorating is loaded in the injection mold, and resin molding. The injection molding simultaneous decoration method is performed in which at least each step of the injection molding step of laminating and integrating the sheet for simultaneous injection molding decoration on the surface of the product is performed in this order.
[0011]
By the injection molding simultaneous decoration method of such a configuration, during the embossing of the uneven pattern, the crystalline resin of the first layer melts its crystal structure to shape the uneven pattern, but after embossing, When the temperature decreases, the resin is recrystallized and the shape of the uneven pattern is fixed, and since the sheet is heated at a temperature lower than the melting point during vacuum forming, the recrystallized crystal structure is maintained. The shape of the pattern can be easily maintained. Therefore, even if the embossed pattern is formed after the preforming step of the sheet or even after the injection molding step, the shape of the pattern is not lost so that the three-dimensional design expression can be simultaneously performed by injection molding. It becomes a decoration method.
[0012]
Further, the injection molding simultaneous decorating method of the present invention is such that the first layer further contains at least a vinylidene fluoride resin and the second layer contains at least an acrylic resin.
With such a configuration, the effects of the present invention described above can be reliably obtained.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0014]
Overview:
First, FIG. 1 is a cross-sectional view conceptually showing the present invention mainly on one embodiment of the sheet for simultaneous decorating by injection molding according to the present invention. FIG. 1A shows a laminated sheet 10 at a stage before embossing, and FIG. 1B shows a sheet S for simultaneous injection molding decoration of the present invention obtained after embossing. FIG. 1 (C) shows a decorative molded product P obtained by decorating simultaneously with injection molding using the sheet S for concurrently decorating with injection molding of FIG. 1 (B).
[0015]
In FIG. 1, the sheet S for simultaneous decorating with injection molding includes a first layer 1 made of a crystalline resin on the front side, a second layer 2 made of a thermoplastic resin on the injection resin side, and a second layer 2 made of a thermoplastic resin. This is an example of a configuration in which a decoration layer 3 is provided on the back side of the layer 2 by printing or the like.
Then, by embossing the laminated sheet 10 as shown in FIG. 1A from the back side to the extent that the front side becomes a convex portion, an injection having a desired uneven pattern 4 as shown in FIG. The sheet S for simultaneous decorating is obtained. At this time, it is preferable that the embossing for forming the concavo-convex pattern 4 is performed at a temperature equal to or higher than the melting point of the crystalline resin of the first layer from the viewpoint of the shape maintaining performance (shape memory) of the concavo-convex pattern. As a result, as shown in FIG. 1 (B), the embossed pattern 4 is embossed so as to penetrate from the back side of the second layer 2 to the front side of the first layer 1 so that On the back side of the second layer 2 located below the convex portion 4a, an uneven pattern forming a concave portion 4b is formed. It should be noted that even though it penetrates to the front side, it is not embossed such that a hole is opened on the front side.
[0016]
Then, if simultaneous injection molding and decorating are performed using the sheet S for simultaneous injection molding and decorating as shown in FIG. 1 (B), preheating at that time (sheet heating is performed by melting the melting point of the crystalline resin of the first layer) And the heat or heat applied to the sheet during injection molding does not cause the uneven pattern to disappear, and the molded article has an uneven pattern 4 on its surface, as shown in FIG. 1 (C). A decorative molded product P having a structure in which the sheet S for simultaneous injection molding and decoration is laminated and integrated on the surface of the product 5 is obtained. Further, the decorative molded product P has an uneven pattern inside the molded product.
[0017]
In addition, as a specific example of the combination of the resins of the first layer 1 and the second layer 2, the crystalline resin of the first layer 1 is a vinylidene fluoride resin, and the thermoplastic resin of the second layer is an acrylic resin. .
[0018]
Injection molding simultaneous decoration sheet:
Hereinafter, each layer of the sheet for simultaneous decoration by injection molding will be described in order.
[0019]
(First layer)
The first layer 1 is a layer located on the outer side, which is the outer side in the state of a decorative molded product obtained by laminating and integrating the sheet for simultaneous injection molding decoration with the resin molded product. In the present invention, by using a crystalline resin for the first layer, even after becoming a decorative molded product by simultaneous injection molding decoration through preliminary forming by vacuum forming, the uneven shape of the uneven pattern remains on the molded product surface Various shape memory properties can be obtained. For this purpose, the embossing for forming the concavo-convex pattern is preferably performed at a temperature equal to or higher than the melting point of the resin of the first layer. The sheet heating during vacuum forming is preferably performed at a temperature lower than the melting point. When the first layer is made of an amorphous resin, the resin is easily softened even if vacuum forming is performed at a sheet heating temperature lower than the melting point, and the shape maintaining performance of the uneven pattern is poor.
[0020]
By the way, generally, in the simultaneous molding by injection molding, in the vacuum forming for preforming the sheet for simultaneous decoration by injection molding (in the description of the present invention, this includes vacuum pressure forming), the sheet heating temperature is In the case of in-line preliminary molding performed on the injection mold by using the vacuum mold as the injection mold, the temperature is about 100 to 120 ° C., and the vacuum molding is performed separately from the injection mold, that is, outside the injection molding machine. In the case of off-line preforming performed in advance with a dedicated vacuum forming die, the temperature is 140 to 170 ° C.
Therefore, if the resin of the first layer is selected from these viewpoints, the crystalline resin of the first layer may be selected from those having a melting point higher than the sheet heating temperature. Therefore, the melting point of the crystalline resin of the first layer is 120 ° C. or more, preferably 130 ° C. or more, if limited to in-line preforming, and 150 ° C. or more, or 170 ° C. or more, including offline preforming. It is preferable to select a suitable resin.
[0021]
Basically, the crystalline resin as described above may be appropriately selected according to the use and the sheet forming form (for example, in-line pre-forming and off-line pre-forming) corresponding thereto. As such a crystalline resin, for example, a fluorine-based resin is a suitable resin. Examples of the fluorine-based resin include a vinylidene fluoride resin. The vinylidene fluoride resin can be used as, for example, a resin having a melting point of 160 ° C. or more, depending on the resin composition. Further, as a fluorine-based resin to be a crystalline resin other than the vinylidene fluoride resin, for example, polytetrafluoroethylene or the like can be given. Vinylidene fluoride resin is too high in cost among fluorine-based resins, and is excellent from the viewpoint of an appropriate melting point and the like. Note that, as the crystalline resin other than the fluorine-based resin, for example, polypropylene, nylon, and the like can be given.
[0022]
The thickness of the first layer depends on the depth of the target uneven pattern (it is intuitively “height” since the uneven pattern is formed by the convex portions on the front side projecting from the back side) and the degree of shape maintenance. It is good. On the other hand, the second layer is mainly responsible for the vacuum formability of the entire sheet for decorating simultaneously with injection molding. Therefore, usually, the thickness of the first layer is smaller than the thickness of the second layer. For example, the thickness of the first layer is about 1/20 to 2/8 of the thickness of the second layer. A specific example of the thickness of the first layer is about 5 to 50 μm although it depends on the thickness of the second layer.
[0023]
(Second layer)
The second layer 2 is usually a layer mainly responsible for the total thickness of the sheet for simultaneous injection molding and decorating more than the first layer, and a layer mainly responsible for vacuum moldability. But also. For this reason, a thermoplastic resin is used for the second layer as a resin having good vacuum moldability. In addition, a resin having moldability capable of vacuum forming a sheet for simultaneous decoration by injection molding at a temperature lower than the melting point of the first layer is used. As such a thermoplastic resin, for example, a polyolefin resin such as polypropylene, an acrylic resin, a vinyl chloride resin, or the like may be used. Among them, an acrylic resin is preferable because it tends to be able to broaden a molding suitable temperature range during sheet heating. Acrylic resins are also preferred in that they have excellent weather resistance and transparency. In addition, the acrylic resin is a suitable combination resin in the case where a vinylidene fluoride resin is used for the first layer, from the viewpoint of the shape maintenance performance of the concavo-convex pattern (shape memoryability), vacuum moldability, and the like.
[0024]
As the acrylic resin, for example, polymethyl (meth) acrylate, polyethyl (meth) acrylate, polybutyl (meth) acrylate, methyl (meth) acrylate-butyl (meth) acrylate copolymer, ethyl (meth) acrylate-butyl A resin such as a (meth) acrylate copolymer or a methyl (meth) acrylate-styrene copolymer (provided that (meth) acrylate means acrylate or methacrylate) is used alone or in a mixture of two or more.
[0025]
The thickness of the second layer is preferably larger than the thickness of the first layer from the viewpoint of the vacuum formability of the sheet, and is about 50 to 200 μm when a specific example of the thickness is given.
[0026]
By the way, the lamination of the first layer and the second layer, these layers are prepared as a resin sheet, and both resin sheets may be laminated via an adhesive, but are more preferable in terms of productivity, cost, and the like. It is preferable that two layers of both resins are co-extruded and melt-laminated, or one is prepared as a resin sheet and melt-extrusion-coated on it. The two-layer coextrusion or melt extrusion coating has the advantage that a thin resin layer, which is impossible as a resin sheet, can be formed. Above all, two-layer coextrusion is more preferable in terms of interlayer adhesion of the laminated sheet.
[0027]
(Uneven pattern)
The concavo-convex pattern 4 of the present invention penetrates from the back side of the second layer 2 to the front side of the first layer 1 with respect to the laminated sheet 10 in which at least the first layer and the second layer are laminated (see FIG. 1A). It is formed by embossing. As a result, as shown conceptually in FIG. 1B, the concave and convex pattern is formed on the back side of the second layer 2 located below the convex portion 4a with respect to the convex portion 4a on the front side of the first layer 1. An uneven pattern having a concave portion 4b corresponding to the convex portion 4a is obtained.
Note that “penetrating” is not embossing such that a hole is opened on the front side of the first layer, but embossing such that a projection is formed on the front side surface of the first layer. Therefore, the tip (valley bottom) of the concave portion as viewed from the back side surface of the second layer always reaches the inside of the first layer in the sheet thickness direction (this is illustrated in FIG. 1B). ] Is not meant. Further, in FIG. 1B, the thickness of the second layer is drawn as zero at the tip of the concave portion, but it may have a finite thickness.
[0028]
In the present invention, the uneven pattern 4 is formed by so-called embossing using heat and pressure. The embossing may be performed by pressing the embossing plate on the surface of the heat-softened resin sheet using a conventionally known hot press type sheet-fed or rotary embossing machine. In the case of embossing, those who receive the pressure of the embossing plate have a soft surface (rubber or the like), and more specifically, in the case of a rotary type, use an impression cylinder whose surface is covered with flexible rubber. It is possible to perform a deep embossing process such that one surface side becomes a convex portion and swells.
[0029]
By the way, in general, when an uneven pattern is formed on the surface of a molded product, it is generally considered that a decorative sheet for that purpose should be embossed from the front side. However, conversely, embossing from the back side, and embossing so that it also protrudes to the front side, the target unevenness pattern is provided on the front side, the present injection molding simultaneous decorating sheet. . As a result, a concave-convex pattern is formed on the back side as a secondary effect, but it can also be used as a concave-convex pattern inside the molded product. On the other hand, even in the case of embossing which results in a concavo-convex pattern having the same depth (height), the concavo-convex pattern in the molded product cannot be obtained by conventional embossing from the front side. As a result, a rich three-dimensional design effect with a feeling of unevenness due to the internal uneven pattern cannot be obtained.
[0030]
The embossing temperature for shaping the concavo-convex pattern, that is, the heating temperature of the laminated sheet to be shaped, is the sheet temperature (more precisely, the sheet surface temperature on the first layer side), preferably the first layer. The temperature should be higher than the melting point of the crystalline resin. That is, as described above, by embossing at a temperature equal to or higher than the melting point, the crystalline resin of the first layer has its crystalline structure melted and the irregular pattern is surely formed, and after embossing, This is because, as the temperature of the heated first layer decreases, the resin of the first layer recrystallizes and the shape of the concavo-convex pattern is fixed, so that a shape retention performance (shape memory property) is obtained.
The temperature of such embossing depends on the resin, but is usually about 160 to 190 ° C.
[0031]
The concavo-convex pattern is not particularly limited as long as it corresponds to the required design expression. For example, there are a satin finish, a grain, a sand pattern, a ground pattern, a linear groove, a wood grain annual ring pattern, a wood grain conduit groove, an uneven pattern on a cleavage face of granite, a surface texture of a cloth grain, a skin squeezing, a character, a geometric pattern, and the like.
[0032]
There is no particular limitation on the pattern of the concavo-convex pattern, but in the size thereof, if the concavo-convex shape of the surface formed so as to penetrate the sheet surface is too small, the heat or heat during vacuum molding or injection molding is used. The uneven shape is easily lost by the heat pressure. Even if the uneven shape is dull, the size of the desired uneven shape that can maintain the shape to the extent that it can be recognized as an uneven pattern in the decorative molded product is the resin content of the first layer and the second layer and the thickness of each of those layers For example, in the case of using a vinylidene fluoride resin having a thickness of 8 μm for the first layer and an acrylic resin having a thickness of 72 μm for the second layer, the sheet for simultaneous simultaneous injection molding and decoration depends on the pre-molding conditions, injection molding conditions and the like. In this case, a good result can be obtained when the height (surface difference) H of the projections 4a forming the irregularities on the front side surface (the surface of the first layer) is 30 μm or more. That is, even if the uneven shape was dull during the process of simultaneous decorating with injection molding, the uneven shape could be left to such an extent that an uneven feeling could be felt at the stage of forming the molded product (see Table 1).
[0033]
Here, in the conceptual sectional view of FIG. 2, the meaning of the size of the uneven pattern 4 including the height H described above is shown. In FIG. 2, the first layer and the second layer are not distinguished from each other, and are illustrated as a sheet S for simultaneous injection molding and decorating in a state where these are stacked. In addition, a concave portion 4b having a depth (rear height difference) D is provided on the seat back side below the convex portion 4a. The width of the opening of the recess 4b is the width L.
[0034]
The depth D and the width L of the concave portion 4b on the back side of the sheet were 50 μm or more and the width L was 500 μm or more under the above-described condition of the height H of 30 μm or more. Generally, if the depth D of the concave portion on the back side is too small, the height H of the convex portion on the front side cannot be sufficiently obtained, and if the frontage L of the concave portion on the back side is too small, a sufficient convex portion on the front side will not be formed. It cannot be provided, and it becomes impossible to sufficiently obtain the shape maintaining performance of the uneven shape up to the molded product.
[0035]
(Decoration layer)
The sheet for simultaneous decorating by injection molding according to the present invention may have only a first layer and a second layer from the viewpoint of having a design with a concavo-convex pattern as an essential component, but is usually as shown in FIG. It is preferable to further provide the decorative layer 3 from the viewpoint that the design can be made higher.
[0036]
The decorative layer 3 is a layer provided for a design property such as a picture expression or for other decoration purposes. Even without the decorative layer, a corresponding design property can be imparted by an uneven pattern, but the design property is further improved. Usually, it is provided in order to make it work. The position where the decorative layer is provided is arbitrary between the first layer and the second layer, but it is preferable to provide the decorative layer on the back surface of the second layer in terms of durability and feeling of painting. In this case, usually, a decorative layer is formed on the back surface of the laminated sheet in which the first layer and the second layer are laminated.
The decoration layer may be formed by a known printing method such as gravure printing, letterpress printing, silk screen printing, offset printing, and inkjet printing. In the case of a solid pattern on the entire surface, a known coating method such as roll coating may be used. In addition, what is necessary is just to select suitably the ink (or coating liquid) used according to the resin of a 1st layer.
[0037]
The ink (or coating liquid) used for forming the decorative layer may be appropriately selected from known ones in consideration of adhesiveness and the like. For example, an acrylic resin, a vinyl chloride-vinyl acetate copolymer, a polyester resin, a polyurethane resin, or the like is used as a binder resin for the ink (or coating liquid). Examples of the coloring agent to be contained in the ink (or coating liquid) include inorganic pigments such as titanium white, zinc white, carbon black, iron black, red iron oxide, cadmium red, ultramarine, cobalt blue, graphite, and titanium yellow. Organic pigments such as phthalocyanine blue, indasulene blue, isoindolinone yellow, quinacridone red and perylene red; metal pigments such as aluminum and brass or metal pigments such as scales; and pearl luster such as powder or scales of titanium dioxide-coated mica. (Pearl) Pigments or dyes are used.
[0038]
In addition, the pattern of the decoration layer is, for example, a satin pattern, a grain pattern, a sand pattern, a ground pattern, a line pattern, a grain pattern, a stone pattern, a cloth pattern, a leather pattern, a tiled pattern, a brick pattern , Geometric figures, characters, symbols, or solid on the entire surface.
[0039]
The decorative layer 3 may be, for example, a metal thin film layer formed by vapor deposition of aluminum, chromium, or the like or formed entirely or partially.
In addition, in the present invention, as the decorative layer, in addition to the design expression such as a grain of wood, functionality may be imparted by a functional layer such as a magnetic material layer or a conductive layer. That is, in the present invention, the decoration or the decoration includes such a functionalization.
[0040]
[Other constituent layers]
The sheet for simultaneous decorating by injection molding of the present invention may be provided with a layer other than the above-mentioned decorative layer as needed. For example, there are a primer layer for enhancing interlayer adhesion, an adhesive layer provided on the back surface side for enhancing adhesion with an injection resin, and the like.
Also, on the back side of the sheet for simultaneous injection molding decoration, if necessary, in order to improve the adhesiveness with the resin molded product as the adherend, corona discharge treatment, plasma treatment, primer coating, etc. An easy adhesion treatment may be performed.
[0041]
As the adhesive layer, a known resin such as a thermoplastic resin or a thermosetting resin is used as a heat-sensitive adhesive. In the thermoplastic resin, for example, one or a mixture of two or more of acrylic resin, chlorinated polyolefin resin, vinyl chloride-vinyl acetate copolymer, thermoplastic urethane resin, thermoplastic polyester resin, polyamide resin, rubber-based resin, and the like Is used. Further, as the thermosetting resin, a urethane resin, an epoxy resin, or the like is used.
[0042]
Injection molding simultaneous decoration method:
Next, in the simultaneous injection molding and decorating method according to the present invention, a sheet manufacturing step (sheet material and method) of the sheet for simultaneous injection molding and decorating used for the so-called simultaneous injection molding and decorating method is a specific step, In addition, a vacuum forming step as a preliminary forming of the sheet is a decorating method in which a specific step is also performed. Hereinafter, the present injection molding simultaneous decorating method will be described in the order of the sheet forming step, the preforming step, and the injection molding step.
[0043]
[Sheet manufacturing process]
The sheet preparation step is a step of preparing and preparing a sheet for simultaneous decoration by injection molding as described above. Therefore, the sheet preparation step according to the present invention is a sheet preparation step in which the layer of the sheet for simultaneous decorating with injection molding and its resin composition, the embossing method for the concavo-convex pattern, the processing temperature, and the like are specified. In other words, in the sheet manufacturing process, as a sheet for simultaneous injection-molding and decorating, at least two layers of a first layer made of a crystalline resin and serving as a front side, and a second layer made of a thermoplastic resin and taken as an injection resin side For the sheet, at a temperature equal to or higher than the melting point of the resin of the first layer, embossing is performed by hot pressure at a depth that penetrates from the back side of the second layer to the front side of the first layer, and the convex portion on the front side of the first layer is formed. On the other hand, the back side of the second layer located below the protruding portion is formed with a concavo-convex pattern forming a concave portion to prepare a sheet for decorating simultaneously with injection molding. In addition, as a preferable specific example of the sheet for simultaneous decorating by injection molding, as described above, the first layer is made of vinylidene fluoride resin and the second layer is made of acrylic resin.
[0044]
(Preliminary molding process)
In the present invention, when using the sheet for simultaneous injection molding and decorating as described above and simultaneously decorating with injection molding in the form with sheet preforming, the sheet heating at the time of sheet preforming is performed by injecting the sheet heating temperature. This is performed at a temperature lower than the melting point of the crystalline resin of the first layer of the sheet for simultaneous decoration during molding. Thereby, the formability at the time of the sheet preforming is ensured, and the shape of the concavo-convex pattern after the preforming can be maintained.
[0045]
In addition, vacuum forming (including vacuum pressure forming) for preforming the sheet for simultaneous decoration by injection molding is roughly classified into a vacuum forming die and a vacuum forming on the injection forming die which also serves as the injection molding die. The form of the in-line preforming to be performed and the form of the vacuum forming mold may be different from the injection molding, that is, the form of the offline preforming in which the vacuum forming is performed outside the injection molding machine.
[0046]
(Injection molding process)
In the injection molding step, after the injection-molding and decorating sheet preformed by the preforming step as described above is loaded in the injection mold, the pair of male and female injection molds is clamped, and then the injection molding is performed. This is a step of injecting resin into the cavity of the mold, filling and solidifying the resin, and laminating and integrating a sheet for simultaneous injection molding and decorating on the surface of the resin molded product. After the resin is solidified, the mold is opened to take out the desired decorative molded product. The decorative molded product is provided with a three-dimensional uneven pattern on the surface (and also inside) of the molded product by the sheet for simultaneous injection molding and decoration as described above.
[0047]
(Injection resin)
The injection resin to be a resin molded product is basically not particularly limited, and may be a known resin. What is necessary is just to select according to the required physical properties of a product, cost, etc. If it is a thermoplastic resin, it may be an ABS (acrylonitrile-butadiene-styrene copolymer) resin, a styrene resin, an acrylic resin, a vinyl chloride resin, a polycarbonate resin, a polyolefin resin, or the like. In the case of a curable resin, a two-liquid curable resin, for example, an uncured resin liquid such as a urethane resin, an unsaturated polyester resin, or an epoxy resin. The thermoplastic resin is melted by heating and injected in a fluid state, and the curable resin (the uncured product) is injected in a flowing state by heating at room temperature or appropriately.
Note that, as the injection resin, a resin colored by adding a coloring agent may be used as appropriate depending on the application. As the colorant, a known colorant as described in the base sheet may be used. In addition, the injection resin optionally contains various known additives such as silica, alumina, talc, calcium carbonate, inorganic powders such as aluminum hydroxide, fillers such as glass fibers, stabilizers, and lubricants. .
[0048]
(Molded product shape)
In addition, the shape of the decorative molded product is such that the sheet lamination surface is a non-planar surface such as an uneven surface or a planar three-dimensional object. Further, the shape of the decorative molded product is arbitrary, such as a plate shape (a flat plate, a curved plate, etc.), a columnar shape, a three-dimensional three-dimensional object, and the like.
[0049]
[Others]
Here, a so-called simultaneous injection molding decoration method will be outlined with reference to the conceptual diagram of FIG. The embodiment described here is an embodiment of in-line preforming in which a preforming step is performed on an injection mold.
[0050]
First, as shown in FIG. 3 (A), the injection mold includes a mold Ma having a runner (runner) and a gate (gate) communicating with the injection nozzle, and has a suction hole 41 on the cavity surface and has a simultaneous injection molding. A pair of molding dies of the mold Mb which also serves as a vacuum molding die for the preforming process of the decorative sheet is used. These molds are made of metal such as iron or ceramics. In the mold open state, the sheet S for simultaneous injection molding decoration is supplied between the two molds Ma and Mb, and the sheet S for simultaneous injection molding decoration is pressed against the mold Mb by a sheet clamp 42 having a frame shape in a plan view. And fix it. At this time, it goes without saying that the back side of the second layer side of the sheet for simultaneous decorating with injection molding is on the injection resin side on the right side in the drawing. Next, as shown in FIG. 3B, the heater 43 retracted at the retracted position outside the mold (in the drawing, above the mold) is appropriately moved and inserted between the two molds. The heating sheet is softened by heating. The heating is, for example, non-contact radiation heating, but may be conduction heating by contact. Then, the sheet is suction-formed from the suction hole and vacuum-formed, and the injection-molding and decorating sheet is preformed along the cavity surface of the mold Mb. Next, the heater is retracted from between the two dies, the two dies are clamped as shown in FIG. 3C, and the cavity formed by the two dies is filled with a resin in a flowing state such as a heated and molten state. After the resin is solidified by cooling or the like, the mold is opened and the molded product is taken out.
Unnecessary portions of the sheet for simultaneous injection molding and decoration are appropriately trimmed, and as shown in FIG. 1 (C), the decorative molded product P in which the sheet for simultaneous injection molding and decoration S is laminated and decorated on the resin molded product 5 is obtained. It is a method that can be obtained.
Then, in the present invention, the uneven pattern 4 is imparted to the surface (and the inside) of the decorative molded article by the sheet for simultaneous injection molding and decorating, and a three-dimensional design expression becomes possible.
[0051]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples.
[0052]
[Example 1]
A sheet S for simultaneous decoration by injection molding as illustrated in FIG. 1B was produced as follows. First, a transparent laminated sheet was prepared in which a first layer 1 (thickness 8 μm) made of vinylidene fluoride resin and a second layer 2 (thickness 72 μm) made of an acrylic resin were stacked. This laminated sheet was produced by a two-layer coextrusion method. Then, on the surface of the second layer side of this laminated sheet, a decorative layer 3 having a design pattern is formed by gravure printing using an ink containing an acrylic resin, thereby forming a laminated sheet 10 having a configuration as shown in FIG. Was prepared.
[0053]
Next, from the surface of the laminated sheet 10 on the side of the second layer 2 (decorative layer 3), embossing is performed to form a dot-shaped uneven pattern 4, and simultaneous injection molding as shown in FIG. A decorative sheet S was produced. The embossing pressure during embossing is 0.6 Pa (6 kgf / cm²), The embossing speed was 5 m / min, and the sheet surface temperature on the front side of the sheet was 160 ° C., the same as the melting point of the vinylidene fluoride resin. The depth of the embossing plate used was 80 μm.
[0054]
Next, the sheet S for simultaneous injection molding decoration was subjected to simultaneous injection molding decoration in the form of in-line preliminary molding using the injection mold as a vacuum mold. That is, the injection is performed using an injection molding machine equipped with an injection molding simultaneous decorating apparatus (including a sheet feeding mechanism, a preforming mechanism, and the like) that enables the sheet to be integrally adhered to the surface of the molded article simultaneously with the injection molding. Between the male mold and the female mold of the molding die, the sheet for simultaneous injection molding decoration was supplied such that the second layer side faced the male mold side having the nozzle, and the simultaneous injection molding decoration was performed. .
In addition, an ABS resin was used as the injection resin, and the preliminary molding was performed by heating and softening the sheet for simultaneous injection molding and decorating so that the sheet temperature became 90 ° C. at the maximum. The mold temperature was 60 ° C. and the injection resin temperature was 235 ° C.
[0055]
The uneven pattern provided on the surface of the obtained decorative molded product had a height (difference in height) of the unevenness of 6.4 μm. In addition, a concavo-convex pattern based on the concavities and convexities on the back side of the sheet was also found inside the molded product. As a result, it was found that a three-dimensional unevenness can be imparted not only to the inside of the molded article, but also to the surface of the molded article, and good results were obtained.
[0056]
Table 1 summarizes the evaluation results and the sizes of the concavo-convex pattern (the state of the sheet for decorating simultaneously with injection molding and the state of the decorative molded product) together with other test examples.
By the way, in Example 1, the size of the concavo-convex pattern in the state of the sheet for simultaneous decorating with injection molding was 47 μm in the height of the front side unevenness, 86 μm in the depth of the back side unevenness, and 536 μm in the width of the opening of the back side unevenness. The unevenness height of the molded product surface was 6.4 μm.
[0057]
[Example 2]
In Example 1, a sheet for simultaneous decoration by injection molding was produced in the same manner as in Example 1 except that the uneven pattern was changed to a sand pattern (sparse). Then, a decorative molded product was produced in the same manner as in Example 1 using the sheet for simultaneous injection molding and decorative. As a result, as shown in Table 1, the height of the unevenness on the surface of the molded product was finally 5.0 μm, and the unevenness was felt well.
[0058]
[Example 3]
In Example 1, a sheet for simultaneous decoration by injection molding was produced in the same manner as in Example 1 except that the embossed pattern was changed to a sand pattern (density) (density sand pattern compared to Example 2). Then, a decorative molded product was produced in the same manner as in Example 1 using the sheet for simultaneous injection molding and decorative. As a result, as shown in Table 1, the height of the unevenness on the surface of the molded product was finally 4.0 μm, and the unevenness was felt well.
[0059]
[Example 4]
In Example 1, a sheet for simultaneous decoration by injection molding was produced in the same manner as in Example 1 except that the uneven pattern was changed to a satin pattern. Then, a decorative molded product was produced in the same manner as in Example 1 using the sheet for simultaneous injection molding and decorative. As a result, as shown in Table 1, the height of the unevenness on the surface of the molded product was finally 5.1 μm, and the unevenness was good.
[0060]
[Reference Example 1]
For reference, an experimental example in which the size of the uneven pattern is too small to be insufficient will be described.
In Example 1, a sheet for simultaneous decorating by injection molding was produced in the same manner as in Example 1 except that the uneven pattern was changed to a wood grain pattern A. Then, a decorative molded product was produced in the same manner as in Example 1 using the sheet for simultaneous injection molding and decorative. However, as shown in Table 1, the size of the uneven pattern in the state of the sheet for simultaneous decorating with injection molding was insufficient (the height of the front-side unevenness was 16 μm, the depth of the back-side unevenness was 17 μm, and the width of the back-side unevenness was 238 μm). In the case of the decorative molded product, the height of the unevenness on the surface of the molded product was only 0.6 μm, and no unevenness was felt.
[0061]
[Reference Example 2]
In Example 1, a sheet for simultaneous injection-molding and decorating was produced in the same manner as in Example 1 except that the concavo-convex pattern was changed to a grain pattern B (a grain pattern different from that of Reference Example 1). Then, a decorative molded product was produced in the same manner as in Example 1 using the sheet for simultaneous injection molding and decorative. However, as shown in Table 1, the size of the concavo-convex pattern in the state of the sheet for simultaneous decoration during injection molding was insufficient (the height of the concavo-convex pattern was 30 μm, the depth of the back-concave pattern was 25 μm, and the width of the back-concave pattern was 253 μm). In the case of the decorative molded product, the height of the unevenness on the surface of the molded product was only 0.6 μm, and no unevenness was felt.
[0062]
[Comparative Example 1]
In Example 1, instead of the laminated sheet in which the first layer and the second layer were laminated, a single-layered acrylic resin sheet having a thickness of 80 μm was used, and was formed on the surface having the decorative layer on the back side. A laminated sheet was produced. Then, the laminated sheet was embossed from the back side to produce a sheet for simultaneous decoration by injection molding. Then, the production of a decorative molded product was attempted by the same injection molding simultaneous decoration method as in Example 1. The sheet heating temperature during embossing was set at 160 ° C, and the sheet heating temperature during preforming was set at 100 ° C. As a result, the irregularities on the sheet surface disappeared at the stage after the preforming.
[0063]
[Table 1]

[0064]
【The invention's effect】
(1) According to the sheet for simultaneous decorating with injection molding of the present invention, the shape of the concavo-convex pattern can be obtained even when the concavo-convex pattern by embossing is in the state of the decorative molded product after the preforming step and further after the injection molding step. Does not disappear, and a three-dimensional unevenness can be imparted not only to the inside of the molded article but also to the surface of the molded article.
The above effect can be obtained more reliably by using a vinylidene fluoride resin for the first layer on the front side and using an acrylic resin for the second layer on the back side.
[0065]
(2) According to the simultaneous injection-molding and decorating method of the present invention, the uneven shape of the uneven pattern by embossing on the sheet for simultaneous injection-molding and decorating is used so that it does not disappear during the simultaneous decorating with injection molding. A decorative molded product having a three-dimensional unevenness on the surface of the molded product as well as inside the molded product can be obtained.
In addition, as a sheet for simultaneous injection molding decoration to be used, using a sheet using vinylidene fluoride resin for the first layer on the front side, and using a sheet using an acrylic resin for the second layer on the back side, the above-described effect is more reliably achieved. Can be obtained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating an example of a sheet for simultaneous decoration by injection molding and a decorative molded product according to the present invention.
FIG. 2 is a sectional view conceptually illustrating the shape of a concavo-convex pattern according to the present invention.
FIG. 3 is a conceptual diagram illustrating, in one embodiment, a simultaneous injection molding decorating method used in the present invention.
[Explanation of symbols]
1 First layer
2 Second layer
3 decoration layer
4 Uneven pattern
4a (front side) convex part
4b (back side) recess
5 Resin molding
10 laminated sheet
41 suction hole
42 sheet clamp
43 heater
D (recess) depth
H (convex) height
L (recess) frontage
Ma injection mold (male type)
Mb injection mold (female mold)
P decorative molding
S Simultaneous decorative sheet for injection molding

Claims

After pre-molding the sheet, the sheet for simultaneous injection molding and decorating to obtain a decorative molded product by integrating the sheet with the surface of the resin molded product at the same time as injection molding,
The sheet for simultaneous injection molding decoration is composed of at least two layers of a first layer made of a crystalline resin and serving as a front side, and a second layer made of a thermoplastic resin and taken as an injection resin side, and It has an embossed pattern by embossing that penetrates from the back side to the front side of the first layer, and the concavo-convex pattern forms a concave part on the back side of the second layer located below the convex part on the front side of the first layer, the injection molding Simultaneous decoration sheet.

The sheet for simultaneous decoration by injection molding according to claim 1, wherein the first layer contains at least a vinylidene fluoride resin, and the second layer contains at least an acrylic resin.

After the preliminary molding of the sheet for simultaneous injection molding decoration, in the simultaneous injection molding decorating method of integrating the sheet for simultaneous injection molding decoration with the surface of the resin molded product at the same time as injection molding to obtain a decorative molded product,
(A) As a sheet for simultaneous decorating by injection molding, a laminated sheet comprising at least two layers of a first layer made of a crystalline resin and having a front side and a second layer made of a thermoplastic resin and having an injection resin side. By performing embossing by heat and pressure at a temperature not lower than the melting point of the resin of the first layer at a depth penetrating from the back side of the second layer to the front side of the first layer, The second layer back side located below the convex portion forms a concave and convex pattern forming a concave portion, a sheet manufacturing step of preparing a sheet for simultaneous injection molding decoration,
(B) a preforming step of preforming the injection molding simultaneous decorating sheet by vacuum forming at a temperature lower than the melting point of the resin of the first layer;
(C) Injecting the resin into the injection mold while the preformed injection-decorative sheet is loaded in the injection mold, and injection-decorative sheet on the surface of the resin molded product. Injection molding process to laminate and integrate
A simultaneous injection-molding and decorating method, wherein at least each of the steps is performed in this order.

The simultaneous injection molding decoration method according to claim 3, wherein the first layer contains at least a vinylidene fluoride resin, and the second layer contains at least an acrylic resin.