JP2004042351A

JP2004042351A - Sheet for molding decoration and method for simultaneous decoration with injection molding

Info

Publication number: JP2004042351A
Application number: JP2002201157A
Authority: JP
Inventors: Hiroyuki Atake; 阿竹　浩之; Tamami Hirano; 平野　珠実; Hironori Kamiyama; 上山　弘徳
Original assignee: Dai Nippon Printing Co Ltd
Current assignee: Dai Nippon Printing Co Ltd
Priority date: 2002-07-10
Filing date: 2002-07-10
Publication date: 2004-02-12
Anticipated expiration: 2022-07-10
Also published as: JP4357804B2

Abstract

<P>PROBLEM TO BE SOLVED: To express a three-dimensional design without eliminating an embossed uneven pattern of a sheet in the simultaneous decoration with injection molding via vacuum forming of the sheet. <P>SOLUTION: The sheet S for molding decoration is composed of at least a first layer 1 and a second layer 2. The first outside layer is constituted of a fluorocarbon resin such as a vinylidene fluoride resin as a crystalline resin, and the second layer is constituted of a thermoplastic resin such as an acrylic resin. In the sheet, the uneven pattern 4 is formed on the suface or back of the first layer by embossment. A decorative layer 5 is formed on the back of the second layer. The embossment is done at a temperature of the melting point of the resin of the first layer or above, and the vacuum forming of the sheet is done at a temperature of the melting point or below. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、加飾成形に使用される成形加飾用シートに関する。特に、真空成形後、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残り、立体的な意匠表現が可能となる成形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成形加飾用シートを積層一体化することで加飾し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、樹脂成形物の成形と同時に成形加飾用シートを積層一体化する方法として射出成形同時加飾方法（特公昭５０−１９１３２号公報、特公昭４３−２７４８８号公報等参照）がある。
【０００３】
また、射出成形同時加飾方法において、加飾成形品の表面に例えば木目導管溝等の立体感を有する凹凸模様を設ける場合には、例えば、次の（１）〜（４）の様にしていた。
（１）射出成形型のキャビティ面に賦形用の凹凸模様を設けておいて、射出成形後の加飾成形品の表面（成形加飾用シート表面）に凹凸模様を賦形する。
（２）成形加飾用シートの基材シートにアクリル系樹脂等の熱可塑性樹脂の樹脂シートを用いて、該基材シートに熱圧を加えるエンボス加工を施して凹凸模様を賦形しておいた成形加飾用シートを使用する。
（３）スクリーン印刷等による印刷で凹凸感を表現する。
【０００４】
（４）紫外線硬化性樹脂等の硬化性樹脂のインキによる盛上げ印刷によって、成形加飾用シートに凹凸模様を付与しておく。例えば、電離放射線硬化性樹脂インキを、ロール凹版（賦形版、成形版胴等とも呼ぶ）の少なくとも凹部に充填させると共に該インキに樹脂シートを接触させ、該インキが樹脂シートとロール凹版との間に保持されている状態で電離放射線を照射して該インキを硬化させた後、樹脂シートをロール凹版から剥離する事で、樹脂シート上に該インキの硬化物からなる凹凸模様を付与する（特開昭５７−８７３１８号公報、特公昭５７−２２７５５号公報、特公昭６３−５００６６号公報、特開平７−３２４７６号公報等参照）。
【０００５】
【発明が解決しようとする課題】
しかしながら、上記（１）〜（４）の如き方法では、次の様な欠点があった。すなわち、（１）の成形品の射出成形時にエンボスを施す方法では、エンボス面が成形品表面に限定されてしまう。従って、内部に凹凸模様を付与できない。しかも、射出成形型のキャビティ面を賦形型として凹凸面にしておく必要があることから、凹凸模様の意匠を変更するときは、成形品の形状が同じであっても、高価な射出成形型ごと交換しなければならず、凹凸模様を自由に変えることが出来なかった。
次に、（２）の基材シートに熱可塑性樹脂シートを用いる場合では、成形品の立体面を加飾する為に、射出成形工程に先立ち真空成形工程にて成形加飾用シートを予備成形する時の熱によって、エンボスされた凹凸模様の凹凸形状が戻ってしまうという問題があった。
次に、（３）のスクリーン印刷等の印刷手法によって凹凸模様を賦形する場合では、インキの転移量に限度があり且つそれが少ない為に、エンボスによる凹凸模様ほど立体感が得られない。
【０００６】
そして、（４）のロール凹版等を使用した紫外線硬化性樹脂等による盛上げ印刷による場合では、上記（３）の印刷手法に比べて、より立体感に優れた凹凸模様を賦形できる。しかし、一般的に樹脂シート側から紫外線を照射して凹凸模様を硬化形成する関係上、樹脂シートに透明シートを使用しないと凹凸模様を付与できない。また、成形加飾用シートに通常の印刷による装飾層を形成する場合、印刷よりも前に凹凸模様を付与すると、その凹凸模様によって印刷時に印刷抜けという印刷不良が発生し易かった。
【０００７】
すなわち、本発明の課題は、成形加飾用シートを用いる射出成形同時加飾方法に於いて、真空成形による予備成形、更には射出成形後に於いても、シート表面や内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、立体的な意匠表現を可能にすることである。
【０００８】
【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、本発明の成形加飾用シートでは、真空成形工程と射出成形工程を経て、樹脂成形物の成形と同時にその表面に一体化して該樹脂成形品を加飾成形品とする為の成形加飾用シートにおいて、該成形加飾用シートは少なくとも第一層及び第二層の２層からなり、加飾成形品の状態で外側に位置させる第一層はフッ素系樹脂による結晶性樹脂からなり、他方の第二層は熱可塑性樹脂からなり、第一層の表側面、裏側面、或いはこれら両面にエンボス加工による凹凸模様が形成されてなる構成とした。
【０００９】
この様な構成とすることで、外側の第一層の樹脂が結晶性樹脂である為に、これを用いた射出成形同時加飾では、第一層の樹脂の融点に着目して、凹凸模様のエンボス加工は該融点以上の温度で行い、シートの真空成形は該融点以下の温度で行う様な成形加飾用シートの使用方法を採用することができる。この為、成形加飾用シート作製の際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、しかも射出成形同時加飾にて真空成形時にシートを再度加熱するときは前記融点以下の温度とすれば、結晶構造は維持されるので凹凸模様の形状は保ち易くなる。従って、エンボス加工による凹凸模様がシートの真空成形工程後、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成形加飾用シートとなる。
【００１０】
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。
【００１１】
また、本発明の加飾成形用シートは、上記いずれかの構成に於いて更に、第二層の裏側面に装飾層を有する構成とした。
この様な構成とすることにより、その装飾層によってより高意匠にできる。
【００１２】
また、本発明の加飾成形用シートは、上記いずれかの構成に於いて更に、第二層の裏側に熱可塑性樹脂シートからなる第三層が積層されてなる構成とした。
この様な構成とすることにより、用途、成形性、意匠性等の点で、第一層及び第二層のみでは加飾成形用シート全体としてのシート総厚が不十分である場合に、この第三層で該シート総厚を賄うことができる。また、第二層自体が、加飾成形用シートの被着体である樹脂成形物との密着性が不十分である場合に、該樹脂成形物との密着性の良い樹脂で第三層を構成して、密着性の向上もできる。
【００１３】
本発明の射出成形同時加飾方法は、成形加飾用シートの真空成形工程と、射出成形工程とを経て、樹脂成形物の成形と同時にその表面に成形加飾用シートを一体化して樹脂成形品を加飾成形品とする射出成形同時加飾方法において、（Ａ）成形加飾用シートとして、少なくとも第一層及び第二層の２層からなり、且つ加飾成形品の状態で外側に位置させる第一層はフッ素系樹脂による結晶性樹脂からなり、他方の第二層は熱可塑性樹脂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エンボス加工を施して、第一層の表側面、裏側面、或いはこれら両面に凹凸模様を形成して、成形加飾用シートを用意するシート作製工程、（Ｂ）上記成形加飾用シートを上記第一層の樹脂の融点以下の温度で真空成形する真空成形工程、（Ｃ）真空成形された上記成形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成形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。
【００１４】
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以下の温度であるので、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真空成形工程後、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。
【００１５】
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。
【００１６】
【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。
【００１７】
概要：
図１の断面図で、本発明による成形加飾用シートの形態例として２形態を例示する。図１（Ａ）の成形加飾用シートＳは、表側から順に、フッ素系樹脂による結晶性樹脂からなる第一層１、熱可塑性樹脂からなる第二層２、印刷等によって絵柄表現等をした装飾層５が積層され、第一層１の表側面に熱圧によるエンボス加工によって凹凸模様４が、シート表面に賦形された構成のシートである。具体的には、例えば、上記第一層１の結晶性樹脂はフッ化ビニリデン樹脂であり、上記第二層の熱可塑性樹脂はアクリル系樹脂である。上記凹凸模様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の点から好ましい。
【００１８】
一方、図１（Ｂ）に示す成形加飾用シートＳの方は、図１（Ａ）で例示した成形加飾用シートＳに対して、更に装飾層５の裏側に、熱可塑性樹脂シートからなる第三層３が積層された構成である。第三層３は、成形加飾用シートとしての総厚確保等の為に設ける。また、被着体である樹脂成形物との密着性向上の為に、必要に応じ適宜、図２で例示する成形加飾用シートＳの如く、最裏面層として熱可塑性樹脂等からなる裏面接着剤層６を設けても良い。なお、図２に例示する成形加飾用シートＳは、図１（Ａ）の構成に対して裏面接着剤層６を追加した構成例である。
【００１９】
そして、上記の様な成形加飾用シートを用いて射出成形同時加飾する際は、成形加飾用シートの予備成形としての真空成形は、シートの加熱温度を第一層の結晶性樹脂の融点以下の温度で行う。なお、更に好ましくは、該シート加熱温度は、第二層の熱可塑性樹脂のガラス転移温度以上の温度で行う。これによって、シート予備成形の為の真空成形時の成形性を確保すると共に、真空成形後の凹凸模様の形状維持もできる。
後は、通常の射出成形同時加飾同様に、真空成形によって予備成形された成形加飾用シートが、射出成形型内に装填された状態で、型締め後の射出成形型内に樹脂を射出して、樹脂成形物の表面に成形加飾用シートを積層一体化する射出成形工程を経れば、図３の断面図で例示する様に、樹脂成形物７の表面に成形加飾用シートＳが積層され、該シートが有する凹凸模様４による立体的意匠を有する所望の加飾成形品Ｐが得られることになる。
【００２０】
成形加飾用シート：
以下、成形加飾用シートの各層から順に説明する。
【００２１】
〔第一層〕
第一層１は、成形加飾用シートが樹脂成形物に積層された後の加飾成形品の状態において、外側に位置させる層であり、且つ凹凸模様の賦形対象層である。本発明ではこの第一層にフッ素系樹脂による結晶性樹脂を用いる。第一層に結晶性樹脂を用いることによって、その融点以上の温度で該凹凸模様のエンボス加工を行い、該融点以下の温度で成形加飾用シートの真空成形を行えば、真空成形後も凹凸模様の形状を維持できる様になる。これに対して、凹凸模様賦形層としての第一層に非結晶性樹脂を用いた場合には、その融点以下の温度でシートの真空成形を行った場合でも、樹脂が軟化し易いので、凹凸模様の形状維持性能が悪い。
【００２２】
ところで、一般的に射出成形同時加飾では、成形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）において、シートの加熱温度は、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には、１００〜１２０℃程度であり、真空成形を射出成形型とは別型で、つまり射出成形機の外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。
【００２３】
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、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面、高すぎ且つ低すぎず適度な融点等の観点から優れている。また、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。
【００２４】
なお、第一層の厚みは、目的とする凹凸模様の深さに応じたものとすれば良い。なお、成形加飾用シート全体としての真空成形性は、第二層等の他層で主体的に担う事が可能である。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。第一層の厚みの具体例を挙げれば１０〜５０μｍ程度である。
【００２５】
〔第二層〕
第二層２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。第一層の融点以下の温度で成形加飾用シートが真空成形できる事が必要であり、この為には、第二層に用いる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。なお、第二層に使用する熱可塑性樹脂をそのガラス転移温度で捉えれば、真空成形性の点で、該ガラス転移温度は真空成形時のシート加熱温度以下となる樹脂が好ましい。一例を挙げれば、アクリル系樹脂では、ガラス転移温度１００℃前後を呈する樹脂等が利用できる。
【００２６】
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。
【００２７】
本発明による成形加飾用シートは、凹凸模様を有する他、層的には前記第一層とこの第二層との積層シートのみでも良いが、通常は更に装飾層等を設けて、より高意匠とする。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良い。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。
【００２８】
前記した第一層が主として凹凸模様の凹凸形状確保を図る層であるのに対して、こちらの第二層の方は、成形加飾用シートとしての真空成形性を確保する為の層である。また、通常は、第一層よりも主体的に成形加飾用シートとしての総厚担う層とする。従って、第二層には第一層よりも真空成形性が良い樹脂を用いる事になる。
これらの点で、第二層の厚みは、通常は、第一層の厚みよりも厚くする。例えば、第二層の厚みの具体例を挙げれば５０〜２００μｍ程度である。なお、第一層の厚み及び第二層との厚み関係は、これに限定されるものでは無い。
【００２９】
〔凹凸模様〕
なお、第一層に形成する凹凸模様４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、木目導管溝、木目年輪模様、砂目、梨地、ヘアライン、万線状溝、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。
なお、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。
【００３０】
また、凹凸模様を賦形する為のエンボス加工の対象とする樹脂シートとしては、第一層単体としてその樹脂シートを用意できるならば、該樹脂シートに対して行う事も可能である。しかし、その後、第二層との積層時の熱等の影響を考えれば、賦形対象の樹脂シートとしては、第一層と第二層とを積層した後の積層シートの方がより好ましい。具体的には、多層（２層）共押出し法で第一層と第二層とを積層した樹脂シートである。
【００３１】
ところで、凹凸模様の賦形対象面は、第一層の表側面、裏側面、或いはこれら両面、いずれでも良い。賦形対称面は、表現する立体意匠による。但し、凹凸模様の賦形対象面は、一般的には第一層の表側面が多い。従って、この場合、通常エンボス加工は、上記積層シートに対して第一層側から行う。一方、賦形対象面が第一層の裏側面の場合には、上記積層シートでは第二層側から行うと良い。第二層側からエンボス加工を施しても、第二層及び第一層の各層の厚みと、エンボス加工の深さに関係するが、第一層の裏側（つまり第一層と第二層との境界面）に凹凸模様を賦形することが出来る。なお、この場合、第二層の裏側面にも凹凸模様ができる。また、第一層の表側面と裏側面の両方に凹凸模様を設けるには、表裏両側からそれぞれエンボス加工を施せば良い。
第一層表側面の凹凸模様では、成形品表面に立体的凹凸感を有する加飾成形品が得られ、第一層裏側面の凹凸模様では、成形加飾用シートのシート層内での内部の立体的凹凸感を有する成形品が得られる。これら両方の凹凸模様を有する場合では、表面及び内部の両方の立体感が得られる。
【００３２】
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樹脂シートの加熱温度は、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１６０〜１９０℃程度である。
【００３３】
〔装飾層〕
次に、装飾層５は絵柄表現等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。また、装飾層は耐久性や塗装感等の点で第二層の裏側面に設けるのが好ましい。この様な装飾層は、生産性等の点で第一層と第二層とを多層共押出で形成する場合でも、第一層と第二層とを積層した積層シートに対してその裏側面に形成すれば良い。
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。
【００３４】
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。
【００３５】
なお、装飾層の絵柄は、例えば、木目模様、石目模様、砂目模様、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。
【００３６】
なお、装飾層５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。
また、装飾層としては、木目等の柄意匠の表現以外に、磁性体層、導電性層等の機能性層等でも良い。つまり加飾乃至は装飾とは、この様な機能性付与も包含する。
【００３７】
〔第三層〕
第三層３は、主とし成形加飾用シートとしての総厚の調整（確保）等の為に適宜設ける。また、第三層３は、被着体との密着性向上を図る為に設けることもできる。この様な第三層３は、第二層の裏側に熱可塑性樹脂シートを積層することで形成できる。なお、第二層の裏側面に装飾層を設けておく場合には、通常は、該装飾層を裏面側からも保護できる点でも、第三層は装飾層の裏側に設ける。ただ、総厚の確保の点では、第二層の裏側に第三層を設け、第三層の裏側に装飾層を設ける構成でも目的は達成できる。
【００３８】
上記の如き第三層３に用いる熱可塑性樹脂としては、ポリプロピレン等の各種ポリオレフィン系樹脂、塩素化ポリオレフィン系樹脂、ＡＢＳ樹脂、或いは例えばポリオレフィン系樹脂とＡＢＳ樹脂との混合樹脂等と異種樹脂同士の混合樹脂を、被着体の材料等に応じて適宜採用すれば良い。
【００３９】
第三層を積層するには、予め熱可塑性樹脂シートとして用意した樹脂シートを、ウレタン樹脂等による公知の接着剤で、ドライラミネーション法等の公知の積層法で貼り合せれば良い。具体的には、例えば、第一層と第二層との積層シートの裏面に装飾層を印刷した印刷シートの該印刷面に対して、接着剤で熱可塑性樹脂シートを貼り合せる。なお、第三層の熱可塑性樹脂シートは、該熱可塑性樹脂の溶融押出塗工によって成膜と同時に第二層の裏側に積層しても良い。
【００４０】
なお、第三層の厚みは、総厚確保や被着体との密着性向上等、その目的にもよるが、総厚確保を図る点では通常は２０〜５００μｍ程度である。
【００４１】
〔裏面接着剤層〕
なお、成形加飾用シートの裏面側は、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の他、これら易接着処理を処理後或いは処理せずに、裏面接着剤層６を設けても良い。
裏面接着剤層６としては、例えば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。
裏面接着剤層は、これら樹脂による接着剤を、グラビア印刷、ロールコート等の公知の印刷又は塗工法により形成する。また、裏面接着剤層の厚さは特に制限は無いが、通常は１〜２０μｍ程度である。
【００４２】
射出成形同時加飾方法：
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、それに用いる成形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形成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、真空成形工程、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、前述した如き成形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、成形加飾用シートの層及びその樹脂組成と融点、また凹凸模様のエンボス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、成形加飾用シートとして、少なくとも第一層及び第二層の２層からなり、且つ加飾成形品の状態で外側に位置させる第一層はフッ素系樹脂による結晶性樹脂からなり、他方の第二層は熱可塑性樹脂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エンボス加工を施して、第一層の表側面、裏側面、或いはこれら両面に凹凸模様を形成して、成形加飾用シートを用意する。なお、該成形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である。
【００４４】
〔真空成形工程〕
本発明では、以上の如き成形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、該シート予備成形の為の真空成形工程にて、シート加熱温度は、成形加飾用シートの第一層の結晶性樹脂が呈する融点以下の温度で行う。更に好ましくは、該シート加熱温度は、第一層の樹脂よりも成形性の良い樹脂としての熱可塑性樹脂（第二層）のガラス転移温度以上の温度とする。これによって、シート予備成形の為の真空成形時の成形性を確保すると共に、真空成形後の凹凸模様の形状維持もできる様になる。
【００４５】
成形加飾用シートを予備成形する為の真空成形工程（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。なお、オフライン予備成形は、インライン予備成形に比べて、一般的に、加飾成形品サイズが大きい場合、シート厚みが厚い場合等に適している。
【００４６】
そして、真空成形時のシート加熱温度は、通常は、インライン予備成形では１００〜１２０℃程度、オフライン予備成形では１４０〜１７０℃程度である。従って、例えば、第一層の結晶性樹脂に融点１７０℃程度のフッ化ビニリデン樹脂を用い、また第二層の熱可塑性樹脂にガラス転移温度１００℃程度のアクリル系樹脂を用いた構成等の成形加飾用シートでは、通常のインライン予備成形或いはオフライン予備形成、どちらの形態にも適用できる。なお、上記予備成形温度は、一般的な温度を示すものであり、成形加飾用シートに用いた樹脂に合わせて、上記範囲外の温度で行っても良い。
【００４７】
〔射出成形工程〕
射出成形工程では、上記の如き真空成形工程によって予備成形された成形加飾用シートを、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成形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、前述如き成形加飾用シートによって、立体的な凹凸模様を付与されている。
【００４８】
なお、射出成形型内に射出する射出樹脂は、通常は加熱溶融させて流動状態となっており、その温度は２００℃以上に及ぶことがあるが、この様な高温の射出樹脂であっても、成形加飾用シートが有する凹凸模様の凹凸形状は維持することができる。つまり、射出成形時の射出樹脂の熱は、真空成形時の熱程には影響しない。例えば、射出樹脂がＡＢＳ樹脂の場合、成形加飾用シートは、射出樹脂温度は２００〜２４０℃程度、また射出成形型の型温度は６０℃程度の温度条件下に晒されるが、そのときの熱が成形加飾用シートに加わるのは一瞬であり、真空成形工程に凹凸模様が耐えられれば、基本的には加飾成形品上では凹凸模様の凹凸形状は残すことができるからである。
【００４９】
〔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。
【００５０】
〔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。
【００５１】
〔その他〕
ここで、図４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、射出成形型上で真空成形工程を行うインライン予備成形の形態である。
【００５２】
先ず、図４（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を有し成形加飾用シートの真空成形工程用の予備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間に成形加飾用シートＳを供給し、型Ｍｂに成形加飾用シート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、成形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４（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で成形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、成形加飾用シートを型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４（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。
成形加飾用シートの不要部分は適宜トリミングすれば、図３の如く、樹脂成形物７に成形加飾用シート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、この成形加飾用シートによって凹凸模様４が加飾成形品に付与され、立体的な意匠表現が可能となる。
【００５３】
【実施例】
以下、実施例及び比較例により本発明を更に詳述する。
【００５４】
〔実施例１〕
図２の如き構成の成形加飾用シートＳを次の様にして作製した。
先ず、結晶性樹脂のフッ素系樹脂としてフッ化ビニリデン樹脂（融点Ｔｍ１６０℃）と、熱可塑性樹脂としてアクリル系樹脂（ガラス転移温度Ｔｇ１００℃）とを、２層共押出しして、厚さ８μｍの第一層１と厚さ７２μｍの第二層２とが積層した透明な積層シートを作製した。
【００５５】
次に、上記積層シートの第二層側の面に、アクリル系樹脂をバインダー樹脂とするインキによるグラビア印刷で装飾層５を形成し、更に、アクリル系樹脂と塩化ビニル−酢酸ビニル共重合体との混合樹脂からなるインキを２回刷りして裏面接着剤層６を形成して印刷シートとした。なお、装飾層５としては、抽象柄の柄層、シルバーの全ベタ層、着色ベタ層を順次形成した。
【００５６】
次に、上記印刷シートの印刷面とは反対側の面、つまりフッ化ビニリデン樹脂からなる第一層の面に対して、熱圧によるエンボス加工を施して、抽象柄を表現した凹凸模様４を形成して、図２の断面図で例示した様な成形加飾用シートＳを得た。
なお、エンボス加工時のシート加熱温度は最大１８０℃で、エンボス版の深さは５０μｍ、形成された凹凸模様４の深さは、４０μｍとなった。
【００５７】
次に、上記で得た成形加飾用シート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すべく、射出成形同時加飾装置に装着して、真空成形型とする射出成形型上で、シート加熱温度１２０℃の条件で、成形加飾用シートをヒータによる非接触加熱で加熱軟化させた後、射出成形型側から真空吸引して、成形加飾用シートを該射出成形型の型形状に真空成形した。
【００５８】
真空成形後の成形加飾用シートについて、凹凸模様の状況を確認したところ、その凹凸形状は残っていた。
この後、射出成形型を型締めして、ＡＢＳ樹脂を射出成形した。なお、射出成形型の型温度は６０℃、射出樹脂温度は２４０℃の条件で行った。
【００５９】
型開き後、加飾成形品を取出し、該成形品に於ける凹凸模様の残存状況を確認したところ、加飾成形品の表面には凹凸模様が残り、その立体的凹凸感により高意匠の成形品となっていた。
【００６０】
〔実施例２〕
実施例１に於いて、印刷シートに対するエンボス加工を、非印刷面側からでは無く印刷面側から行い、凹凸模様を第一層の裏側面にシート内部の凹凸模様として形成した成形加飾用シートを作製した。そして、この成形加飾用シートを用いて、実施例１と同様の射出成形同時加飾を行い加飾成形品を作製した。
【００６１】
その結果、真空成形後の成形加飾用シートには、凹凸模様の凹凸形状が残っていた。また、加飾成形品に於いては、成形品表面は射出樹脂の圧力と熱により射出成形型のキャビティ面を写して平坦であったが、シート内部に凹凸模様が残っている為に、表面から見ると加飾成形品内部に凹凸があり、この立体的凹凸感による高意匠の成形品が得られた。
【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、アクリル系樹脂（ガラス転移温度Ｔｇ１０５℃）からなる単層で透明な厚さ８０μｍの樹脂シートを用いた。この他は、実施例１と同様にして、成形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。
【００６３】
その結果、真空成形後の成形加飾用シートには、凹凸模様の凹凸形状が消失していた。この為、次の射出成形工程は中止した。
【００６４】
〔比較例２〕
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、アクリル系樹脂（ガラス転移温度Ｔｇ１０５℃）からなる単層で透明な厚さ８０μｍのアクリル系樹脂シートを用いた。また、印刷シートに対するエンボス加工は、印刷面側から行い、アクリル系樹脂シートの裏側面に凹凸模様を形成した。この他は、実施例１と同様にして、成形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。
【００６５】
その結果、真空成形後の成形加飾用シートには、凹凸模様の凹凸形状が消失していた。この為、次の射出成形工程は中止した。
【００６６】
【発明の効果】
（１）　本発明の成形加飾用シートによれば、エンボス加工による凹凸模様が真空成形工程後、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加飾成形品が得られる。
（２）更に、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。
（３）また、第二層の裏側面に装飾層を設ければ、より高意匠にできる。
（４）また、第二層の裏側に熱可塑性樹脂シートからなる第三層も積層すれば、シート総厚確保や、被着体との密着性向上等が図れる。
【００６７】
（５）本発明の射出成形同時加飾方法によれぱ、使用する成形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、真空成形工程等で消失しない様にして、立体的な意匠表現ができる加飾成形品が得られる。
（６）更に、使用する成形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】本発明による成形加飾用シートをその２形態で例示する断面図。
【図２】本発明による成形加飾用シートの別の１形態を例示する断面図。
【図３】本発明による加飾成形品の一例を示す断面図。
【図４】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　　第三層
４　　凹凸模様
５　　装飾層
６　　裏面接着剤層
７　　樹脂成形物
４１　吸引孔
４２　シートクランプ
４３　ヒータ
Ｍａ　射出成形型（雄型）
Ｍｂ　射出成形型（雌型）
Ｐ　　加飾成形品
Ｓ　　成形加飾用シート[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a molded decorative sheet used for decorative molding. In particular, the present invention relates to a molding decorative sheet and an injection molding simultaneous decorating method, in which an embossed pattern remains even after vacuum molding and further after injection molding, thereby enabling three-dimensional design expression.
[0002]
[Prior art]
Decorative molded articles decorated by laminating and integrating molded decorative sheets on the surface of a resin molded article are used in various applications. As a typical method for obtaining such a decorative molded product, there is a simultaneous decorating method by injection molding (Japanese Patent Publication No. 50-19132, Japanese Patent Publication No. 43-27488).
[0003]
In addition, in the simultaneous decorating method of injection molding, when the surface of the decorative molded article is provided with a three-dimensional unevenness pattern such as a wood channel groove, for example, the following (1) to (4) are used. Was.
(1) An uneven pattern for shaping is provided on the cavity surface of the injection mold, and the uneven pattern is formed on the surface of the decorative molded article after injection molding (the surface of the molded decorative sheet).
(2) Using a resin sheet of a thermoplastic resin such as an acrylic resin as the base sheet of the formed decorative sheet, the base sheet is subjected to embossing by applying heat and pressure to form an uneven pattern. Use the formed decorative sheet.
(3) Express a feeling of unevenness by printing by screen printing or the like.
[0004]
(4) An embossed pattern is formed on the molded decorative sheet by raising printing with a curable resin ink such as an ultraviolet curable resin. For example, an ionizing radiation-curable resin ink is filled into at least a concave portion of a roll intaglio (also referred to as a shaping plate, a molding plate cylinder, or the like) and a resin sheet is brought into contact with the ink. After the ink is cured by irradiating it with ionizing radiation while being held in between, the resin sheet is peeled off from the roll intaglio to give an uneven pattern made of a cured product of the ink on the resin sheet ( JP-A-57-87318, JP-B-57-22755, JP-B-63-50066, and JP-A-7-32476.
[0005]
[Problems to be solved by the invention]
However, the methods (1) to (4) have the following disadvantages. That is, in the method (1) of embossing during injection molding of a molded article, the embossed surface is limited to the surface of the molded article. Therefore, an uneven pattern cannot be provided inside. In addition, since the cavity surface of the injection mold needs to be formed as an irregularity surface as a shaping die, when changing the design of the uneven pattern, even if the shape of the molded product is the same, an expensive injection mold is required. Had to be replaced, and the pattern could not be changed freely.
Next, in the case where a thermoplastic resin sheet is used as the base sheet in (2), in order to decorate the three-dimensional surface of the molded product, the formed decorative sheet is preformed in a vacuum forming process prior to the injection molding process. There is a problem that the uneven shape of the embossed uneven pattern returns due to the heat at the time of heating.
Next, in the case of shaping the concavo-convex pattern by a printing method such as screen printing in (3), the transfer amount of the ink is limited and the amount is small, so that the three-dimensional effect cannot be obtained as much as the embossed concavo-convex pattern.
[0006]
Then, in the case of (4) by stencil printing using an ultraviolet curable resin or the like using a roll intaglio or the like, it is possible to form a concavo-convex pattern having a more three-dimensional appearance than the printing method of (3). However, because the resin sheet is generally irradiated with ultraviolet rays to cure and form the uneven pattern, the uneven pattern cannot be provided unless a transparent sheet is used for the resin sheet. In addition, when a decorative layer is formed on a molded decorative sheet by ordinary printing, if a concavo-convex pattern is provided before printing, printing defects such as printing omission during printing are likely to occur due to the concavo-convex pattern.
[0007]
That is, the object of the present invention is to provide a simultaneous decoration method for injection molding using a sheet for molding and decoration, preforming by vacuum forming, and even after injection molding, by embossing provided on the sheet surface or inner surface. An object of the present invention is to enable a three-dimensional design expression so that the uneven pattern does not disappear.
[0008]
[Means for Solving the Problems]
Therefore, in order to solve the above-mentioned problems, in the molded decorative sheet of the present invention, through a vacuum forming step and an injection molding step, the resin molded article is integrated with the surface thereof simultaneously with the molding of the resin molded article to decorate the resin molded article. In the decorative sheet for forming a molded article, the molded decorative sheet is composed of at least two layers, a first layer and a second layer, and the first layer positioned outside in the state of the decorative molded article is a fluorine-based sheet. The second layer is made of a crystalline resin made of a resin, and the other second layer is made of a thermoplastic resin. The first layer has a structure in which the front and rear surfaces, the back surface, or both surfaces have an embossed pattern formed by embossing.
[0009]
By adopting such a configuration, since the resin of the outer first layer is a crystalline resin, in the simultaneous injection molding decoration using the same, attention is paid to the melting point of the resin of the first layer, and the uneven pattern is formed. The embossing can be performed at a temperature equal to or higher than the melting point, and the vacuum forming of the sheet can be performed at a temperature equal to or lower than the melting point. For this reason, at the time of embossing at the time of producing a molded decorative sheet, the crystalline resin of the first layer melts its crystal structure and forms an uneven pattern. Is recrystallized to fix the shape of the concavo-convex pattern.Moreover, when heating the sheet again during vacuum forming by simultaneous injection molding decoration, if the temperature is not higher than the melting point, the crystal structure is maintained, so the concavo-convex pattern is maintained. The shape is easier to keep. Therefore, even if the embossed pattern is formed after the vacuum forming step of the sheet, and even after the injection molding step, the shape of the pattern is not lost so that a three-dimensional design expression can be obtained. It becomes.
[0010]
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.
[0011]
Further, the decorative molding sheet of the present invention has any one of the above-described structures, and further includes a decorative layer on the back surface of the second layer.
By adopting such a configuration, a higher design can be achieved by the decorative layer.
[0012]
Further, the decorative molding sheet of the present invention has a configuration in which, in any one of the above configurations, a third layer made of a thermoplastic resin sheet is further laminated on the back side of the second layer.
By adopting such a configuration, when the total thickness of the decorative molding sheet as a whole is insufficient with only the first layer and the second layer in terms of application, moldability, designability, etc. The third layer can cover the total thickness of the sheet. In addition, when the second layer itself has insufficient adhesion with the resin molded product, which is the adherend of the decorative molding sheet, the third layer is formed of a resin having good adhesion with the resin molded product. By configuring, the adhesion can be improved.
[0013]
The simultaneous injection molding and decorating method of the present invention is a resin molding method in which a molding and decorating sheet is integrated with the surface of a molded resin article simultaneously with the molding of the molded resin article through a vacuum molding step of the molded and decorated sheet and an injection molding step. In the simultaneous injection molding and decorating method in which a product is a decorative molded product, (A) the molded decorative sheet is composed of at least two layers, a first layer and a second layer, and is outwardly formed in the state of the decorative molded product. The first layer to be located is made of a crystalline resin made of a fluorine-based resin, and the other second layer is subjected to embossing at a temperature equal to or higher than the melting point of the resin of the first layer with respect to a laminated sheet made of a thermoplastic resin. A sheet producing step of forming a concavo-convex pattern on the front side, the back side, or both sides of the first layer to prepare a formed decorative sheet, and (B) forming the formed decorative sheet on the resin of the first layer. A vacuum forming step of performing vacuum forming at a temperature below the melting point, (C Injection molding in which a resin is injected into an injection mold while the vacuum-molded decorative sheet is loaded in the injection mold, and the molded decorative sheet is laminated and integrated on the surface of the resin molded product. And a simultaneous injection molding decorating method in which at least each of the steps is performed in this order.
[0014]
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 heating during vacuum forming is at a temperature equal to or lower than the melting point, the recrystallized crystal structure is maintained. The shape of the pattern can be easily maintained. For this reason, even when the embossed pattern is formed after the vacuum forming step of the sheet and further after the injection molding step, the shape of the concavo-convex pattern is not lost so that the three-dimensional design expression can be simultaneously performed by injection molding. It becomes a decoration method.
[0015]
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.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0017]
Overview:
In the cross-sectional view of FIG. 1, two examples of the form of the formed decorative sheet according to the present invention are illustrated. The decorative sheet S in FIG. 1 (A) was designed such that a first layer 1 made of a crystalline resin of a fluorine-based resin, a second layer 2 made of a thermoplastic resin, and a pattern were formed by printing or the like in order from the front side. The decorative layer 5 is laminated, and the concavo-convex pattern 4 is formed on the front surface of the first layer 1 by embossing with hot pressure on the sheet surface. Specifically, for example, 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. The embossing for forming the uneven pattern 4 is preferably performed at a temperature equal to or higher than the melting point of the crystalline resin of the first layer from the viewpoint of maintaining the shape of the uneven pattern.
[0018]
On the other hand, the molded decorative sheet S shown in FIG. 1 (B) further includes a thermoplastic resin sheet on the back side of the decorative layer 5 with respect to the molded decorative sheet S illustrated in FIG. 1 (A). The third layer 3 is laminated. The third layer 3 is provided for securing the total thickness as a molded decorative sheet. In addition, in order to improve the adhesion to the resin molded article as the adherend, the backside adhesive layer made of a thermoplastic resin or the like as the outermost backside layer, as necessary, as in the case of the molded decorative sheet S illustrated in FIG. An agent layer 6 may be provided. 2 is a configuration example in which a back adhesive layer 6 is added to the configuration of FIG. 1A.
[0019]
And when decorating simultaneously with injection molding using the molded decorative sheet as described above, vacuum forming as preliminary molding of the molded decorative sheet is performed by heating the sheet at a heating temperature of the crystalline resin of the first layer. Perform at a temperature below the melting point. In addition, more preferably, the sheet heating temperature is a temperature equal to or higher than the glass transition temperature of the thermoplastic resin of the second layer. Thereby, the formability at the time of vacuum forming for sheet preforming is ensured, and the shape of the concavo-convex pattern after vacuum forming can be maintained.
After that, in the same manner as ordinary simultaneous injection molding and decorating, in the state where the molded decorative sheet preformed by vacuum molding is loaded in the injection mold, the resin is injected into the injection mold after clamping. Then, through an injection molding step of laminating and integrating the molded decorative sheet on the surface of the resin molded product, as illustrated in the cross-sectional view of FIG. 3, the molded decorative sheet is formed on the surface of the resin molded product 7. S is laminated, and a desired decorative molded product P having a three-dimensional design by the concavo-convex pattern 4 of the sheet is obtained.
[0020]
Molded decorative sheet:
Hereinafter, each layer of the molded decorative sheet will be described in order.
[0021]
(First layer)
The first layer 1 is a layer positioned on the outside in the state of the decorative molded product after the molded decorative sheet is laminated on the resin molded product, and is a shaping target layer having an uneven pattern. In the present invention, a crystalline resin of a fluororesin is used for the first layer. By using a crystalline resin for the first layer, the embossing of the uneven pattern is performed at a temperature equal to or higher than the melting point, and vacuum forming of the formed decorative sheet is performed at a temperature equal to or lower than the melting point. The shape of the pattern can be maintained. On the other hand, when the non-crystalline resin is used for the first layer as the concavo-convex pattern shaping layer, even if the sheet is vacuum formed at a temperature equal to or lower than its melting point, the resin is easily softened. Poor shape maintenance performance of uneven pattern.
[0022]
By the way, generally, in simultaneous molding by injection molding, in a vacuum forming for preforming a sheet for forming and decorating (in the description of the present invention, this includes vacuum pressure forming), the heating temperature of the sheet is vacuum forming. In the case of in-line preforming performed on an injection mold by using the mold as an injection mold, the temperature is about 100 to 120 ° C., and vacuum molding is performed separately from the injection mold, that is, outside the injection molding machine. In the case of preliminarily performed offline preforming, 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.
[0023]
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, and the vinylidene fluoride resin can be used as a resin having a melting point of 160 ° C. or higher. In addition, as a fluorine-based resin to be a crystalline resin other than the vinylidene fluoride resin, polytetrafluoroethylene or the like can be given. Vinylidene fluoride resin is excellent among fluororesins from the viewpoints of cost, moderate and not too high and not too low. Examples of the crystalline resin other than the fluororesin include, for example, polypropylene and nylon.
[0024]
The thickness of the first layer may be determined according to the desired depth of the uneven pattern. In addition, the vacuum formability of the entire sheet for forming and decorating can be mainly borne by another layer such as the second layer. Therefore, usually, the thickness of the first layer is smaller than the thickness of the second layer. A specific example of the thickness of the first layer is about 10 to 50 μm.
[0025]
(Second layer)
For the second layer 2, a thermoplastic resin is used as a resin having good vacuum moldability. It is necessary that the molded decorative sheet can be vacuum-formed at a temperature equal to or lower than the melting point of the first layer. For this purpose, as the thermoplastic resin used for the second layer, for example, a polyolefin resin such as polypropylene, acrylic A system 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, if the thermoplastic resin used for the second layer is grasped by its glass transition temperature, a resin whose glass transition temperature is equal to or lower than the sheet heating temperature at the time of vacuum molding is preferable from the viewpoint of vacuum moldability. For example, as the acrylic resin, a resin having a glass transition temperature of about 100 ° C. or the like can be used.
[0026]
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.
[0027]
The formed decorative sheet according to the present invention has a concavo-convex pattern, and may be a laminated sheet of the first layer and the second layer. Design. 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 in terms of productivity, cost, and the like, more preferably, It is preferred that two layers of both resins are melt-extruded by co-extrusion, or one is prepared as a resin sheet and then melt-extruded and applied thereto. 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.
[0028]
While the above-mentioned first layer is a layer mainly for securing the uneven shape of the uneven pattern, the second layer is a layer for ensuring vacuum formability as a formed decorative sheet. . In addition, usually, it is a layer that plays a greater role as a molded decorative sheet than the first layer. Therefore, a resin having better vacuum moldability than the first layer is used for the second layer.
In these respects, the thickness of the second layer is usually larger than the thickness of the first layer. For example, a specific example of the thickness of the second layer is about 50 to 200 μm. Note that the thickness relationship between the first layer and the second layer is not limited to this.
[0029]
(Uneven pattern)
The concavo-convex pattern 4 formed on the first layer may be in accordance with a required design expression, and is not particularly limited. For example, there are a wood grain conduit groove, a wood grain ring pattern, a grain of sand, a satin finish, a hairline, a linear groove, a concave and convex pattern of a cleavage surface of granite, a texture of a cloth grain, a skin squeezing, a character, a geometric pattern and the like.
In the present invention, the concavo-convex 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.
[0030]
In addition, as a resin sheet to be embossed for forming a concavo-convex pattern, the resin sheet can be prepared as long as the resin sheet can be prepared as a first layer alone. However, considering the influence of heat or the like upon lamination with the second layer, the laminated sheet after laminating the first layer and the second layer is more preferable as the resin sheet to be shaped. Specifically, it is a resin sheet in which a first layer and a second layer are laminated by a multilayer (two-layer) coextrusion method.
[0031]
By the way, the shaping target surface of the concavo-convex pattern may be any of the front surface, the back surface, or both surfaces of the first layer. The shaping symmetry plane depends on the three-dimensional design to be expressed. However, the shaping target surface of the concavo-convex pattern generally has many front surfaces of the first layer. Therefore, in this case, the embossing is usually performed on the laminated sheet from the first layer side. On the other hand, when the surface to be shaped is the back surface of the first layer, the above-described laminated sheet may be formed from the second layer side. Even if embossing is performed from the second layer side, the thickness of each layer of the second layer and the first layer and the depth of the embossing are related, but the back side of the first layer (that is, the first layer and the second layer (A boundary surface) can be formed with an uneven pattern. In this case, an uneven pattern is also formed on the back side surface of the second layer. Further, in order to provide the uneven pattern on both the front and back surfaces of the first layer, embossing may be performed on both the front and back surfaces.
In the unevenness pattern on the front surface of the first layer, a decorative molded product having a three-dimensional unevenness on the surface of the molded product is obtained. In the unevenness pattern on the back surface of the first layer, the interior of the formed decorative sheet in the sheet layer is obtained. A molded article having a three-dimensional unevenness is obtained. In the case of having both these concavo-convex patterns, a stereoscopic effect on both the surface and the inside can be obtained.
[0032]
The embossing temperature for shaping the concavo-convex pattern, that is, the heating temperature of the resin sheet to be shaped, is preferably set to a temperature equal to or higher than the melting point of the crystalline resin of the first layer. 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 uneven pattern is fixed. The temperature of such embossing depends on the resin, but is usually about 160 to 190 ° C.
[0033]
(Decoration layer)
Next, the decorative layer 5 is a layer provided for the purpose of pattern expression and the like. Even if there is no decorative layer, a corresponding design property or the like can be imparted by an uneven pattern, but it is usually provided to further improve the design property or the like. . The decorative layer is preferably provided on the back side of the second layer from the viewpoint of durability and painting feeling. Such a decorative layer, even when the first layer and the second layer are formed by multi-layer co-extrusion in terms of productivity and the like, the back surface of the laminated sheet in which the first layer and the second layer are laminated. What is necessary is just to form.
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.
[0034]
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.
[0035]
The pattern of the decorative layer is, for example, a grain pattern, a stone pattern, a grain pattern, a cloth pattern, a leather pattern, a tiled pattern, a brickwork pattern, a geometric pattern, a character, a symbol, or a solid surface. .
[0036]
The decorative layer 5 may be, for example, a metal thin film layer formed entirely or partially by vapor deposition of aluminum, chromium, or the like.
The decorative layer may be a functional layer such as a magnetic layer or a conductive layer, in addition to the expression of the pattern design such as wood grain. That is, the decoration or the decoration includes such a functional addition.
[0037]
(Third layer)
The third layer 3 is appropriately provided mainly for adjusting (securing) the total thickness as a molded decorative sheet. Further, the third layer 3 can be provided to improve the adhesion to the adherend. Such a third layer 3 can be formed by laminating a thermoplastic resin sheet on the back side of the second layer. When a decorative layer is provided on the back side of the second layer, the third layer is usually provided on the back side of the decorative layer also in that the decorative layer can be protected from the back side. However, in terms of securing the total thickness, the object can be achieved by a configuration in which the third layer is provided on the back side of the second layer and the decorative layer is provided on the back side of the third layer.
[0038]
As the thermoplastic resin used for the third layer 3 as described above, various polyolefin-based resins such as polypropylene, chlorinated polyolefin-based resins, ABS resins, or, for example, a mixed resin of a polyolefin-based resin and an ABS resin or the like and a different resin. What is necessary is just to employ | adopt a mixed resin suitably according to the material etc. of an adherend.
[0039]
In order to laminate the third layer, a resin sheet prepared in advance as a thermoplastic resin sheet may be bonded with a known adhesive such as a urethane resin or the like by a known lamination method such as a dry lamination method. Specifically, for example, a thermoplastic resin sheet is bonded with an adhesive to the printed surface of the printed sheet on which the decorative layer is printed on the back surface of the laminated sheet of the first layer and the second layer. In addition, the thermoplastic resin sheet of the third layer may be laminated on the back side of the second layer at the same time as film formation by melt extrusion coating of the thermoplastic resin.
[0040]
The thickness of the third layer depends on the purpose, such as securing the total thickness and improving the adhesion to the adherend. However, the thickness is usually about 20 to 500 μm in terms of securing the total thickness.
[0041]
(Back adhesive layer)
In addition, the back surface side of the sheet for forming and decorating is appropriately subjected to an easy adhesion treatment such as a corona discharge treatment, a plasma treatment, a primer coating or the like, as necessary, in order to improve the adhesiveness with a resin molded product as an adherend. Alternatively, the back surface adhesive layer 6 may be provided after or without performing these easy bonding processes.
As the back adhesive layer 6, for example, 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.
The back adhesive layer is formed by using an adhesive made of these resins by a known printing or coating method such as gravure printing or roll coating. The thickness of the back adhesive layer is not particularly limited, but is usually about 1 to 20 μm.
[0042]
Injection molding simultaneous decoration method:
In the simultaneous injection molding and decorating method according to the present invention, in contrast to the so-called simultaneous injection molding and decorating method, a sheet manufacturing step (sheet material and method) of a sheet for forming and decorating to be used is a specific step, and The vacuum forming step as preforming is also a decorating method with a specific step. Hereinafter, the present injection molding simultaneous decorating method will be described in the order of sheet forming step, vacuum forming step, and injection molding step.
[0043]
[Sheet manufacturing process]
The sheet preparation step is a step of preparing and preparing a molded decorative sheet as described above. Therefore, the sheet manufacturing step according to the present invention is a sheet manufacturing step in which the layer of the molded decorative sheet, its resin composition and melting point, the embossing temperature of the uneven pattern, and the like are specified. In other words, in the sheet manufacturing process, the formed decorative sheet is composed of at least two layers, the first layer and the second layer, and the first layer positioned outside in the state of the decorative molded product is made of a crystalline resin made of a fluorine-based resin. The second layer is made of resin, and the other second layer is subjected to embossing at a temperature equal to or higher than the melting point of the resin of the first layer on the laminated sheet made of the thermoplastic resin, and the front surface, the back surface, or these A concave / convex pattern is formed on both sides to prepare a molded decorative sheet. In addition, as a preferable specific example of the formed decorative sheet, as described above, the first layer contains at least vinylidene fluoride resin, and the second layer contains at least acrylic resin.
[0044]
(Vacuum forming process)
In the present invention, using the decorative sheet for molding as described above, when decorating simultaneously with injection molding in the form with sheet preforming, in the vacuum forming step for the sheet preforming, the sheet heating temperature, This is performed at a temperature equal to or lower than the melting point of the crystalline resin of the first layer of the formed decorative sheet. More preferably, the sheet heating temperature is a temperature equal to or higher than the glass transition temperature of a thermoplastic resin (second layer) as a resin having better moldability than the resin of the first layer. Thereby, the formability during vacuum forming for sheet preforming is ensured, and the shape of the concavo-convex pattern after vacuum forming can be maintained.
[0045]
The vacuum forming process (including vacuum pressure forming) for preforming the decorative sheet is roughly divided into an in-line preparatory step in which a vacuum forming die is also used as an injection molding die and vacuum forming is performed on the injection molding die. The form of molding and the vacuum mold may be different from the injection mold, that is, the form of offline preforming in which vacuum molding is performed outside the injection molding machine. In addition, the offline preforming is generally suitable for the case where the size of the decorative molded product is large, the case where the sheet thickness is large, and the like, as compared with the inline preforming.
[0046]
The sheet heating temperature during vacuum forming is usually about 100 to 120 ° C. for in-line pre-forming and about 140 to 170 ° C. for off-line pre-forming. Therefore, for example, molding such as a structure using a vinylidene fluoride resin having a melting point of about 170 ° C. as the crystalline resin of the first layer and an acrylic resin having a glass transition temperature of about 100 ° C. as the thermoplastic resin of the second layer. The decorating sheet can be applied to both normal in-line preforming and off-line preforming. The preforming temperature indicates a general temperature, and may be set at a temperature outside the above range in accordance with the resin used for the decorative sheet for forming.
[0047]
(Injection molding process)
In the injection molding step, after the molded decorative sheet preformed by the vacuum molding step as described above is loaded in the injection mold, the pair of male and female injection molds is clamped. This is a step of injecting resin into the cavity, filling and solidifying the resin, and laminating and integrating a molded decorative sheet 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 article is provided with a three-dimensional uneven pattern by the decorative sheet for molding as described above.
[0048]
In addition, the injection resin injected into the injection mold is usually heated and melted to be in a fluid state, and its temperature may reach 200 ° C. or higher. The uneven shape of the uneven pattern of the formed decorative sheet can be maintained. That is, the heat of the injection resin at the time of injection molding does not affect the heat at the time of vacuum molding. For example, when the injection resin is an ABS resin, the molded decorative sheet is exposed to a temperature condition of the injection resin temperature of about 200 to 240 ° C. and the temperature of the injection mold of about 60 ° C. This is because heat is instantaneously applied to the formed decorative sheet, and if the concave-convex pattern can withstand the vacuum forming step, the concave-convex pattern of the concave-convex pattern can basically be left on the decorative molded product.
[0049]
(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. .
[0050]
(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.
[0051]
[Others]
Here, a so-called simultaneous injection molding decorating 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 vacuum forming step is performed on an injection mold.
[0052]
First, as shown in FIG. 4A, as an injection molding die, a mold Ma having a runner (runner) and a gate (gate) communicating with an injection nozzle, and a suction hole 41 on a cavity surface for forming and decorating. A pair of molds of the mold Mb which also serves as a preforming mold for the vacuum forming step of the sheet is used. These molds are made of metal such as iron or ceramics. In the mold open state, the formed decorative sheet S is supplied between the two molds Ma and Mb, and the formed decorative sheet S is fixed to the mold Mb by pressing with a sheet clamp 42 having a frame shape in plan view. In this case, it goes without saying that the back side of the second layer side of the molded decorative sheet is on the injection resin side on the right side in the drawing. Next, as shown in FIG. 4B, 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. Is heated and softened. The heating is, for example, non-contact radiation heating, but may be conduction heating by contact. Then, it is sucked from the suction hole and vacuum formed, and the formed decorative 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. 4C, and a 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.
By trimming the unnecessary portion of the formed decorative sheet as needed, a decorative molded product P in which the formed decorative sheet S is laminated and decorated on the resin molded product 7 as shown in FIG. 3 can be obtained.
And in the present invention, the concavo-convex pattern 4 is given to the decorative molded article by the molded decorative sheet, and a three-dimensional design expression is possible.
[0053]
【Example】
Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.
[0054]
[Example 1]
A molded decorative sheet S having a configuration as shown in FIG. 2 was produced as follows.
First, two layers of a vinylidene fluoride resin (melting point Tm: 160 ° C.) as a fluororesin of a crystalline resin and an acrylic resin (glass transition temperature Tg: 100 ° C.) as a thermoplastic resin are co-extruded to form an 8 μm thick second resin. A transparent laminated sheet in which one layer 1 and the second layer 2 having a thickness of 72 μm were laminated was produced.
[0055]
Next, on the surface of the second layer side of the laminated sheet, a decoration layer 5 is formed by gravure printing with an ink using an acrylic resin as a binder resin, and further, an acrylic resin and a vinyl chloride-vinyl acetate copolymer are formed. Was printed twice to form a back adhesive layer 6 to obtain a printed sheet. As the decorative layer 5, an abstract pattern layer, a silver solid layer, and a colored solid layer were sequentially formed.
[0056]
Next, the surface opposite to the printing surface of the printing sheet, that is, the surface of the first layer made of vinylidene fluoride resin, is subjected to embossing by heat and pressure to form an uneven pattern 4 expressing an abstract pattern. Thus, a sheet S for forming and decorating as illustrated in the cross-sectional view of FIG. 2 was obtained.
The sheet heating temperature at the time of embossing was 180 ° C. at the maximum, the depth of the embossing plate was 50 μm, and the depth of the formed concavo-convex pattern 4 was 40 μm.
[0057]
Next, the molded decorative sheet S obtained above was mounted on an injection molding simultaneous decorating apparatus in order to perform simultaneous injection molding decorating in the form of in-line preliminary molding using the injection mold as a vacuum molding die. After the sheet for forming and decorating is heated and softened by non-contact heating with a heater under the condition of a sheet heating temperature of 120 ° C. on the injection mold to be a vacuum forming mold, vacuum suction is performed from the injection mold side to form. The decorative sheet was vacuum formed into the shape of the injection mold.
[0058]
When the state of the concavo-convex pattern was confirmed for the formed decorative sheet after vacuum forming, the concavo-convex shape remained.
Thereafter, the injection molding die was closed, and the ABS resin was injection molded. The injection molding was performed at a mold temperature of 60 ° C and an injection resin temperature of 240 ° C.
[0059]
After opening the mold, the decorative molded product was taken out, and the state of the uneven pattern remaining on the molded product was confirmed. As a result, the uneven pattern remained on the surface of the decorative molded product. Had become a product.
[0060]
[Example 2]
In Example 1, a molded decorative sheet in which embossing of a printed sheet is performed not from the non-printing side but from the printing side, and the concavo-convex pattern is formed on the back side of the first layer as the concavo-convex pattern inside the sheet Was prepared. Using the formed decorative sheet, the same injection molding and decoration as in Example 1 was performed to produce a decorative molded product.
[0061]
As a result, in the formed decorative sheet after vacuum forming, the uneven shape of the uneven pattern remained. In the decorative molded product, the surface of the molded product was flat by copying the cavity surface of the injection mold by the pressure and heat of the injection resin. When viewed from above, there were irregularities inside the decorative molded article, and a highly designed molded article due to this three-dimensional unevenness was obtained.
[0062]
[Comparative Example 1]
In Example 1, in place of the laminated sheet in which the first layer and the second layer were laminated, a single-layer transparent resin sheet having a thickness of 80 μm and made of an acrylic resin (glass transition temperature Tg: 105 ° C.) was used. . Otherwise, in the same manner as in Example 1, a molded decorative sheet was produced. Then, by the same injection molding simultaneous decoration method as in Example 1, production of a decorative molded product was attempted.
[0063]
As a result, the concavo-convex shape of the concavo-convex pattern had disappeared in the formed decorative sheet after vacuum forming. Therefore, the next injection molding process was stopped.
[0064]
[Comparative Example 2]
In Example 1, instead of the laminated sheet in which the first layer and the second layer were laminated, a single-layer transparent 80 μm-thick acrylic resin sheet made of an acrylic resin (glass transition temperature Tg: 105 ° C.) was used. Using. In addition, embossing was performed on the printing sheet from the printing surface side, and an uneven pattern was formed on the back side surface of the acrylic resin sheet. Otherwise, in the same manner as in Example 1, a molded decorative sheet was produced. Then, the production of a decorative molded product was attempted by the same injection molding simultaneous decoration method as in Example 1.
[0065]
As a result, the concavo-convex shape of the concavo-convex pattern had disappeared in the formed decorative sheet after vacuum forming. Therefore, the next injection molding process was stopped.
[0066]
【The invention's effect】
(1) According to the molded decorative sheet of the present invention, the three-dimensional pattern is formed so that the uneven pattern by the embossing does not disappear even after the vacuum forming step and further after the injection molding step. The decorative molded article which can express a typical design can be obtained.
(2) Further, if a vinylidene fluoride resin is used for the first layer on the front side and an acrylic resin is used for the second layer on the back side, the above effect can be more reliably obtained.
(3) Further, if a decorative layer is provided on the back side surface of the second layer, a higher design can be achieved.
(4) If a third layer made of a thermoplastic resin sheet is also laminated on the back side of the second layer, the total thickness of the sheet can be ensured, and the adhesion to the adherend can be improved.
[0067]
(5) According to the simultaneous injection-molding and decorating method of the present invention, the three-dimensional shape is obtained by preventing the uneven shape of the uneven pattern due to the embossing on the used molding and decorating sheet from disappearing in the vacuum forming step or the like. A decorative molded product capable of design expression is obtained.
(6) Further, if a sheet using vinylidene fluoride resin for the first layer on the front side and an acrylic resin for the second layer on the back side is used as the molded decorative sheet to be used, the above effect can be more reliably achieved. Can be obtained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating a molded decorative sheet according to the present invention in two forms.
FIG. 2 is a cross-sectional view illustrating another form of the molded decorative sheet according to the present invention.
FIG. 3 is a sectional view showing an example of a decorative molded product according to the present invention.
FIG. 4 is a conceptual diagram illustrating an injection molding simultaneous decorating method used in the present invention in one embodiment.
[Explanation of symbols]
1 First layer
2 Second layer
3 Third layer
4 Uneven pattern
5 Decoration layer
6 Back adhesive layer
7 Resin molding
41 suction hole
42 sheet clamp
43 heater
Ma injection mold (male type)
Mb injection mold (female mold)
P decorative molding
S Forming decorative sheet

Claims

Through a vacuum molding step and an injection molding step, a molded decorative sheet for integrating the resin molded article with the surface thereof at the same time as molding the resin molded article to form a decorative molded article,
The formed decorative sheet is composed of at least two layers, a first layer and a second layer. The first layer positioned outside in the state of the decorative molded product is made of a crystalline resin of a fluorine-based resin, and the other second layer. A molded decorative sheet, wherein the layer is made of a thermoplastic resin, and the front and rear surfaces, the back surface, or both surfaces of the first layer are formed with an embossed pattern by embossing.

The molded decorative sheet 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.

The molded decorative sheet according to claim 1 or 2, further comprising a decorative layer on the back surface of the second layer.

The molded decorative sheet according to any one of claims 1 to 3, wherein a third layer made of a thermoplastic resin sheet is further laminated on the back side of the second layer.

Through the vacuum molding process of the molded decorative sheet and the injection molding process, simultaneously with the molding of the resin molded product, the molded decorative sheet is integrated on the surface and the resin molded product is simultaneously decorated with the molded product In the decoration method,
(A) As a decorative sheet for molding, the first layer composed of at least two layers, a first layer and a second layer, and the first layer positioned outside in the state of the decorative molded product is made of a crystalline resin of a fluororesin, The other second layer is embossed on the laminated sheet made of thermoplastic resin at a temperature equal to or higher than the melting point of the resin of the first layer, and the surface of the first layer, the back side, or an uneven pattern on these both sides. Forming a sheet for preparing a decorative sheet for molding,
(B) a vacuum forming step of vacuum forming the formed decorative sheet at a temperature equal to or lower than the melting point of the resin of the first layer;
(C) The resin is injected into the injection mold while the vacuum-molded decorative sheet is loaded in the injection mold, and the molded decorative sheet is laminated and integrated on the surface of the resin molded product. Injection molding process,
A simultaneous injection-molding and decorating method, wherein at least each of the steps is performed in this order.

The injection molding simultaneous decoration method according to claim 5, wherein the first layer contains at least a vinylidene fluoride resin, and the second layer contains at least an acrylic resin.