JP2004098372A

JP2004098372A - Thermoplastic resin molded product and manufacturing method therefor

Info

Publication number: JP2004098372A
Application number: JP2002261063A
Authority: JP
Inventors: Kenji Ebitani; 戎谷　賢二
Original assignee: Yamaha Living Tech Co Ltd
Current assignee: Yamaha Living Tech Co Ltd
Priority date: 2002-09-06
Filing date: 2002-09-06
Publication date: 2004-04-02

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermoplastic resin molded product to which the sharpness and high design effect are provided by thermally fusing a laminate of a thermoplastic resin film, of which the rear surface is decoratively printed, to a thermoplastic resin substrate, and a manufacturing method therefor. <P>SOLUTION: Decorative printing is applied to the rear surface of the surface layer 20 comprising thermoplastic resin film or sheet to provide an intermediate layer 23 comprising the thermoplastic resin film or sheet to the printed surface. The intermediate layer 23 is fused to a thermoplastic resin substrate 25 as a binder fused to obtain a thermoplastic resin molded product 10. The surface layer 20 comprises a material having a melt softening temperature higher than that of the thermoplastic resin substrate 25 by 20°C or higher while the intermediate layer 23 has the melt softening temperature which is lower than that of the surface layer 20 by 20°C or higher and is within a range of -50-50°C with respect to the melt softening temperature of the thermoplastic resin substrate 25. The laminate of the surface layer 20 and the intermediate layer 22 is simultaneously laminated by using heat at the time of extrusion molding of the thermoplastic resin substrate 25. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は熱可塑性樹脂成形品及びその製造方法に係り、更に詳しくは、熱可塑性樹脂基材に熱可塑性樹脂フィルム若しくはシートを積層した熱可塑性樹脂成形品及びその製造方法に関する。
【０００２】
【従来の技術】
従来より、冷蔵庫のドア、ファンヒーターの外板などの家電機器用外装材や、ユニットバス等の内装壁材等に高鮮鋭性と意匠性とを有するフィルムラミネート鋼板が使用されている。このフィルムラミネート鋼板の製造方法としては以下の方法が知られている。
（１）表層を構成するポリエステル系樹脂からなる熱可塑性樹脂フィルムの裏面にグラビア印刷を行い、当該印刷面に接着剤を介してポリ塩化ビニル樹脂或いはポリオレフィン樹脂等からなる熱可塑性樹脂フィルムを中間層として積層し、当該中間層と鋼板との間に接着剤を介して前記鋼板にラミネートする方法。
（２）鋼板にグラビア印刷を施した後に当該印刷面上にクリアー塗装を施す方法。
これらの製造方法のうち、（２）の製造方法では、塗装ラインに印刷設備を必要とすることから、（１）の製造方法が主流となっている（例えば、特開２０００−５２４８６号公報参照）。
【０００３】
【発明が解決しようとする課題】
しかしながら、前記フィルムラミネート鋼板においては、積層フィルムを構成する表層に印刷用インキの凹凸がゆず肌となって現れる現象がある。従って、その対策として、鋼板に積層フィルムを貼り合わせる際に、加熱加圧することでインキの凹凸を強制的に中間層に吸収させる方法が採用されている。しかしながら、この場合には、鋼板を予備加熱しなければならず、製造工数の増加により製造コストの上昇や、熱圧のための余分なエネルギーが使用されるという不都合がある。また、他の対策としては、インキの凹凸を吸収するために積層フィルム内にクリアー層を設ける場合もあるが、この場合においても、多層化に伴って製造コストが上昇するという不都合が不可避となる。
【０００４】
更に、前述したゆず肌が現れる不都合とは別に、鋼板自身に起因した不都合もある。例えば、錆の対策として、鋼板の断面は樹脂フィルムで被覆する必要があり、そのための曲げ、絞り加工等の工程（工数）がコスト上昇の要因となる他、切断し難さや、樹脂シートに比べて重い等、取扱性も悪いものとなる。
【０００５】
また、フィルムラミネート鋼板は、一般的に平らで凹凸意匠がつけ難い。従って、一部ではコールドプレスにより凹状の模様を形成したり、積層フィルムの表面側一層のみをカッターで研削除去して凹状の目地をつけることも行われているが、この場合には金型が必要となってコストが高くなってしまったり、フィルム自体が薄いため（フィルムの厚み１００〜２５０μｍフィルムが一般的に使用される）、高い研削精度が要求されて精密な設備が必要となる他、深みのある凹凸もつけ難いものとなる。
【０００６】
ところで、家電機器用の外装材や住設備用の内装壁材に適用できるものとして、熱可塑性樹脂フィルム若しくはシートの積層体を熱可塑性樹脂基材に積層した熱可塑性樹脂成形品が知られている。この成形品は、押出し、カレンダー成形、熱プレス、熱ロールプレス等の手法を用いた熱融着によって得ることができるが、熱融着による積層の場合には、用いられる熱可塑性樹脂同士の溶融軟化温度が近い樹脂同士の積層が通常となる。従って、このような熱可塑性樹脂成形品にあっては、表層をなすフィルム若しくはシートの裏面に印刷された柄が熱融着時の熱で伸びたり、歪んだりして精度が悪くなり、印刷初期における柄の再現性が悪いという不都合を招来する。例えば、透明アクリルシートのＡＢＳ押出し同時ラミネート積層板であるアクリルバック印刷シート／ＡＢＳにおいては、ラミネート時にアクリルシートが押出しＡＢＳ樹脂温度の影響で柄が伸びてしまうという問題を生ずる。
【０００７】
また、前述した熱融着で成形されている熱可塑性樹脂成形品に使用される樹脂（アクリル、ＡＢＳ、ＨＩＰＳ、ＰＳ、ＰＰ、塩化ビニル等）は、一般的に耐溶剤性、耐洗剤性、耐薬性の点で十分ではないという問題がある。例えば、アクリル樹脂成形品の表面をアルコール、シンナーで拭くと溶解したり、ソルベントクラックを発生することが知られている。更に、アクリル樹脂成形品の場合、吸水率が高く寸法変化が大きいという問題もある。また、ポリ塩化ビニルフィルムは、燃焼に伴うダイオキシンの発生の恐れがあり、廃棄物処理上で問題となっている。
【０００８】
【発明の目的】
本発明は、鋼板に熱可塑性樹脂シート若しくはフィルムを積層する場合の種々の不都合を改善するために案出されたものであり、その目的は、基材として熱可塑性樹脂基材を用い、当該基材に対し、表層の裏面に加飾印刷が施された熱可塑性樹脂フィルム若しくはシートの積層体を熱融着することで製造工数の削減や、取扱いの容易性等を確保しつつ鮮鋭性及び高意匠性を備えた熱可塑性樹脂成形品及びその製造方法を提供することにある。
【０００９】
また、本発明の他の目的は、柄の再現性に優れ、しかも耐溶剤、耐薬剤、耐洗剤性及び吸水率問題等に優れた表面性能を備えた熱可塑性樹脂成形品及びその製造方法を提供することにある。
【００１０】
【課題を解決するための手段】
前記目的を達成するため、本発明は、熱可塑性樹脂フィルム若しくはシートからなる表層に加飾印刷を行い、その印刷面側に熱可塑性樹脂フィルム若しくはシートからなる中間層を介して熱可塑性樹脂基材に積層した熱可塑性樹脂成形品であって、
前記表層は、溶融軟化温度が前記熱可塑性樹脂基材の溶融軟化温度に対して２０℃以上高いものによって構成され、
前記中間層は、溶融軟化温度が前記表層の溶融軟化温度より低く、しかも前記熱可塑性樹脂基材の溶融軟化温度に対して−５０℃〜＋５０℃の範囲のものによって構成される、という構成を採っている。このような構成とすることで、融点差を利用した融着により、柄の再現性に優れた熱可塑性樹脂成形品を提供することができる。また、基材として鋼板を用いていないため、鋼板を基材として用いた場合の前述した種々の不都合を解消することができる。
【００１１】
本発明において、前記表層は、ＰＥＴにより構成することが好ましい。これにより、ＰＥＴフィルム若しくはシートが有する耐溶剤、耐薬剤、耐洗剤性及び吸水率問題等の優れた表面性能を備えた熱可塑性樹脂成形品を提供することが可能となる。
【００１２】
また、前記中間層と前記熱可塑性樹脂基材との間にプライマー層若しくは接着剤を設けてもよい。これにより、熱可塑性樹脂フィルム若しくはシートと熱可塑性樹脂基材との接着強度を更に向上させることが可能となる。
【００１３】
更に、本発明は、熱可塑性樹脂基材に熱可塑性樹脂フィルム若しくはシートからなる中間層を介して熱可塑性樹脂フィルム若しくはシートからなる表層を積層した熱可塑性樹脂成形品の製造方法において、
前記熱可塑性樹脂基材の溶融軟化温度に対して２０℃以上高い溶融軟化温度を有する表層の一方の面に加飾印刷を行い、
溶融軟化温度が前記表層の溶融軟化温度より低く、しかも前記熱可塑性樹脂基材の溶融軟化温度に対して−５０℃〜＋５０℃の範囲の溶融軟化温度を有する
熱可塑性樹脂からなる中間層を前記印刷面側に積層し、
前記熱可塑性樹脂基材の成形時の熱を利用して前記中間層を融着して前記熱可塑性樹脂基材に積層する、という方法を採っている。
【００１４】
なお、本明細書において、「溶融軟化温度」とは、以下の測定方法による温度について用いられる。
すなわち、測定は、ホットプレート上に硬貨（耐熱性があり、熱伝導率が高く変形しないもの印となるものであればよい）を置いた状態で、ホットプレートを昇温させてフィルム若しくはシートを硬貨上に置き、その上から一定の圧力（約１Ｋｇ／ｃｍ^２）を加えるための重りを載せることにより行われる。そして、約３０秒放置した後の、シートの場合には硬貨接触面側に硬貨痕（艶消え及凹み変形）が付き始める温度、フィルムの場合には艶消え及び溶解するときの温度を溶融軟化温度とする。
【００１５】
本発明における熱可塑性樹脂成形品は、表層となる製品表面が溶融軟化温度の高い透明な熱可塑性樹脂フィルム若しくはシートによって構成され、当該表層の裏面に一色以上（抽象柄、幾何学固定柄、全面ベタ印刷、プライマー印刷）の絵柄加飾印刷がグラビア印刷、スクリーン印刷、インキジェット印刷等によって施される。中間層として、ＰＯ、ＰＰ、ＡＢＳ等の熱可塑性樹脂フィルム若しくはシートが用いられる。この中間層は、表層の印刷面側に接着剤を介してドライラミネートされて積層フィルム若しくはシートとされる。また、中間層は、接着剤の役割をもたせてバインダーとして利用され、熱可塑性樹脂基材の押出し又はカレンダー成形時に積層フィルム若しくはシートを同時ラミネートすることにより熱融着することで複層の板状若しくはシート状の熱可塑性樹脂成形品を得ることができる。このように、中間層を溶融して接着剤として作用させることで、印刷によって生じ得る積層フィルム若しくはシートの凹凸が吸収され、化粧鋼板よりも高鮮鋭性に富み、且つ、表面の平滑性に優れた成形品表面とすることができる。なお、必要により、中間層の裏面に、更に密着力（接着力）を付与するために、透明なプライマー樹脂、接着剤等を予め塗布する処理を行って同時ラミネートすることも可能である。
【００１６】
本発明で利用可能な表層は、代表的にはポリエステル系樹脂、例えば、ＰＥＴ、ＰＢＴ等のポリアルキレンテレフタレート等の熱可塑性樹脂である。中でも、最も一般的なのは、結晶性ＰＥＴ（溶融軟化温度２５６〜２６７℃）であれば、ＰＥＴの有する表面性能を効果的に発揮することができ、また、表層と熱可塑性樹脂基材との溶融軟化温度の差を有効利用することにより、アクリル、ＡＢＳ、ＨＩＰＳ、ＰＰ、ＰＳ、塩化ビニル等の樹脂を表層として採用した場合に見られる耐溶剤性、耐洗剤性等の種々の問題や、柄の再現性低下、接着剤の塗布、乾燥工程等が別途に必要となる問題を解決することができる。尤も、本発明は、融着相手である熱可塑性樹脂基材との関係において前述した溶融軟化温度の差があれば良く、結晶性ＰＥＴと非結晶性ＰＥＴのブレンドフィルム若しくはシート、非結晶性ＰＥＴフィルム若しくはシート、又は軟質ＰＥＴフィルム若しくはシートも利用可能である。また、溶融軟化温度の差を利用しているため、表層の柄の伸びがないばかりでなく、熱による表面の艶消えもなく、印刷柄の精度、再現性も良好である。更に、押出し或いはカレンダー成形等による同時ラミネートによる成形であるため、ラミネート皺や異物混入の発生確率を低下させることができるとともに、フィルム巻きなおし工数や、別途に接着剤を塗布する工程等を削減して生産効率を向上させることができる。また、成形時に、押出し樹脂に凹凸が吸収されるため、表面平滑性も向上することとなる。
【００１７】
また、本発明における熱可塑性樹脂基材としては、例えば、ＡＢＳ、アクリル、ＰＳ、ＨＩＰＳ、ＰＰ、非結晶ポリエステル、無機フィラー含有熱可塑性樹脂、熱可塑性樹脂低発泡品等が例示でき、それぞれ透明樹脂、顔料及び染料からなる着色剤で着色した半透明、不透明品のものを任意に選択することができる。
【００１８】
本発明において、表層と熱可塑性樹脂基材の溶融軟化温度は、前述したように、表層が熱可塑性樹脂基材よりも２０℃以上高い差が必要であるが、これは、熱可塑性樹脂基材の押出し樹脂温度を溶融軟化温度より高く設定しないと未溶解ペレットを含む未溶解物が残るため、これを回避する必要があるためである。なお、熱可塑性樹脂基材に対する表層の溶融軟化温度は５０℃以上の差があることが一層好ましい。これは、表面の艶の問題と押し出し温度のばらつきを考慮するためである。
【００１９】
また、本発明は、押出し時の熱（押出し樹脂の樹脂温度）を利用して中間層及び必要に応じて設けられるプライマー層若しくは接着剤を溶融して熱可塑性樹脂基材に融着するものであり、この場合の中間層の溶融軟化温度は、前述したように、押出し熱可塑性樹脂基材の溶融軟化温度と比較して−５０℃〜＋５０℃の範囲である。従って、例えば、熱可塑性樹脂基材の溶融軟化温度が１５０℃であれば、中間層の溶融軟化温度は１００〜２００℃であればよいことになる。なお、中間層と熱可塑性樹脂基材の溶融軟化温度差は、好ましくは−２０℃〜＋２０℃である。これは融着時に中間層が押出し樹脂の熱を受けて溶融軟化温度以上の温度に達しなければならず、押出し樹脂温度が前記範囲外の関係であまりにも低すぎると密着性が著しく低下する一方、前記範囲外であまりにも押出し樹脂温が高すぎると融着前に柄がボケたり、歪んだり、シワが発生したりするためである。また、押出し樹脂温度のバラツキ（押出し後、ラミネート融着までの間で樹脂温度が下がる）も考慮する必要があり、前記範囲内で融着可能であることが確認されている。但し、表層と中間層との関係においては、表層自体が有する前記特性を維持する上で、当該表層の溶融軟化温度が、中間層の溶融軟化温度より高いことが必要である。このように、本発明は、表層、押出し熱可塑性樹脂基材、中間層若しくは必要に応じて用いられるプライマー、接着剤を前記条件（範囲）で相互に組み合わせることにより、前述した種々の問題を解決することのできる熱可塑性樹脂積層成形品を得ることができる。
【００２０】
本発明は、フィルムラミネート鋼板と異なり、前記熱可塑性樹脂の積層フィルム若しくはシートを用いることにより、当該積層フィルムが持つ印刷による意匠性と併せて任意に凹凸意匠を付与することが容易となる。また、成形品の厚みは任意であるため、高い精度、精密な設備が必要でなく、積層フィルムと熱可塑性基材の一部を機械加工によって取り去ることで任意の凹状意匠が可能となる。更に、熱可塑性樹脂の利点を生かして金型を不要とし、成形品製造後に熱プレス、真空成形等の手法で凹凸意匠を付与することも容易となる。
【００２１】
図１に示されるように、本発明に係る熱可塑性樹脂成形品１０は、シート状に形成された状態で、合板、ＭＤＦ等からなるパネル基材１１の面に、反応性ホットメルト等の接着剤１２を介して積層体とされ、これが家電機器用外装材や、ユニットバス等の内装壁材等に利用される。熱可塑性樹脂成形品１０は、図２に詳細に示されるように、熱可塑性樹脂フィルム若しくはシートからなる表層２０と、これの図中下面側に所定のインキで印刷された印刷層２１と、当該印刷層２１に接着層２２を介して積層された熱可塑性樹脂フィルム若しくはシートからなる中間層２３と、この中間層２３をバインダーとして融着される熱可塑性樹脂基材２５とにより構成されている。また、図３に示されるように、前記印刷層２１の面に、全面ベタ印刷２６を施したもの、図４に示されるように、グラビアロール等で印刷されたプライマー層、或いは、接着層２７を設けたもの、更に、図５に示されるように、熱可塑性樹脂基材２５の層に達するように機械加工で彫り込んで目地２８を形成したもの等によって構成することができる。なお、目地２８を彫り込む程度は特に限定されるものではない。但し、基材２５に達する深さの目地を形成する際に、中間層の隠蔽色と異なる色の熱可塑性樹脂基材とすると、印刷された柄と凹形状、或いは、中間層の色と目地色といったように意匠性を高めることができる。
【００２２】
【実施例】
以下に、本発明に係る熱可塑性樹脂成形品の実施例を示す。
【００２３】
［実施例１］
以下の表１に示されるように、表層として、溶融軟化温度が２２５℃のＰＥＴフィルムを用い、その裏面に印刷を行い、更に、色ムラ防止のための全面ベタ印刷を施した。そして、その印刷面側に、中間層として溶融軟化温度が１５０℃のＰＯフィルムを接着剤を介して積層した。融着の相手側となる熱可塑性樹脂基材は顔料を添加して着色した不透明ＡＢＳ樹脂（溶融軟化温度１２５℃）とした。この熱可塑性樹脂基材を押出し成形すると同時に、その押出し時の熱によって前記中間層を溶融し、ラミネートして熱可塑性樹脂成形品を得た。当該成形品の外観は極めて良好であり、また、密着性も良好であった。
本実施例では、前記熱可塑性樹脂成形品の全体厚みを２．０ｍｍに固定したが、押出し成形であるため、厚みの調整は任意とすることができる。得られた熱可塑性樹脂成形品は、図１に示されるように、合板、ＭＤＦ等からなるパネル基材に接着して化粧パネルとした。なお、パネル基材としては、パーチクルボード、無機板、金属板等も選択可能である。
【００２４】
［実施例２］
実施例１における中間層と熱可塑性樹脂基材との間にプライマー層を設けた以外は同一の条件で成形を行った。この実施例では、プライマー層の介在により、密着性においても優れた結果を得ることができた。
【００２５】
［実施例３］
実施例２におけるプライマー層に代えてホットメルト系の接着剤を設けた。その他は実施例１と同一の条件で成形を行った。この実施例においても、接着剤の介在により、密着性においても優れた結果を得ることができた。
【００２６】
［実施例４］
熱可塑性樹脂基材として、溶融軟化温度が１２０℃となるＨＩＰＳ樹脂を用いた以外は実施例１と同一の条件で成形を行った。この実施例においても、実施例１と同様の外観及び密着性を得ることができた。
【００２７】
［実施例５］
熱可塑性樹脂基材として、溶融軟化温度が１６０℃のＰＰ樹脂を用いた以外は実施例２と同一の条件で成形を行った。
【００２８】
［実施例６］
表層として、溶融軟化温度が２０５℃のＰＢＴフィルムを用いる一方、熱可塑性樹脂基材として、溶融軟化温度が１２５℃のＡＢＳ樹脂を用いた。その他は、実施例１と同一の条件で成形を行った。
【００２９】
［実施例７］
実施例６と同様の表層を用いるとともに、実施例３と同様の中間層及び接着剤を用い、実施例５と同様の熱可塑性樹脂基材を用いた。
【００３０】
［実施例８］
表層として、溶融軟化温度が２４５℃となるＰＣＴフィルムを用い、実施例１と同様の中間層を用いた。また、熱可塑性樹脂基材は、溶融軟化温度が１３０℃となるメタクリル樹脂を用いた。
【００３１】
［実施例（比較例）９］
熱可塑性樹脂基材として溶融軟化温度が８５℃のＰＥ樹脂を用いた以外は、実施例１と同一の条件で成形を行った。この実施例では、表層と熱可塑性樹脂基材とが密着する積層を行うことができず、従って、成形品の外観の評価をすることもできなかった。これは、中間層の溶融軟化温度が熱可塑性樹脂基材の溶融軟化温度に対して高すぎたことに起因するものと考えられる。
【００３２】
［実施例（比較例）１０］
中間層として溶融軟化温度が１０５℃となるＰＶＣフィルムを用いる一方、熱可塑性樹脂基材として溶融軟化温度が１９５℃のＰＣ樹脂を用いた。その他は、実施例１と同一の条件で成形を行った。この実施例においては、成形品の外観において印刷ぼけを生じた。これは、中間層の溶融軟化温度が熱可塑性樹脂基材の溶融軟化温度に対して低すぎたことに起因しているものと考えられる。
【００３３】
【表１】

【００３４】
表１から明らかなように、本発明の条件を満足する実施例１ないし８の熱可塑性樹脂成形品において、外観及び密着性（碁盤目試験クリアー）は良好であった。強制的に剥離を試みたが、印刷層が熱可塑性樹脂基材側の面に転写されて剥離する状態であった。
【００３５】
また、表面性においては、耐溶剤性等の表面性能試験で、同様の条件で成形した表面アクリル品（５０μｍＰＭＭＡフィルム／ＡＢＳシートと比較したが、本発明にかかる熱可塑性樹脂シートの表面の方が耐溶剤性、耐薬品性等優れた結果を示した。
【００３６】
なお、前記熱可塑性樹脂成形品の前記樹脂基材裏面に接着剤（ＰＵＲ接着剤）を塗布してパネル基材に接着した。接着性を向上させるため、プライマーを塗布して接着性向上させる方法と、熱可塑性樹脂基材面をワイドサンダーで研削して粗してから接着剤を塗布して接着する（物理接着、アンカー効果付与）方法で接着力向上可能であった。その結果ＡＢＳ、ＨＩＰＳ、ＰＰ、メタクリル樹脂ともにパネル基材との接着力は向上し、化粧パネル（木口、端面、裏面処理して浴室パネル、キッチンパネル、パーテション等の住設関連部材パネルとして利用）として使用可能な問題ない物性を得ることができた。
【００３７】
【発明の効果】
以上説明したように、本発明によれば、フィルムラミネート鋼板による種々の不都合を解消することができる他、印刷された柄の再現性に優れた特有の表面性能を有する熱可塑性樹脂成形品を得ることができる、という従来にない効果を得ることができる。すなわち、溶融軟化温度の差を特定の範囲にして積層することで、表層を形成する熱可塑性樹脂フィルム若しくはシート面に設けられた印刷柄の伸びがなく、熱による表面の艶消えもなく、印刷柄の精度・再現性が良好となる。また、シート状の熱可塑性樹脂成形品を形成した後の当該成形品と熱可塑性樹脂基材との融着ではなく、押出し（カレンダー成形）同時ラミネートで融着するものであるため、ラミネートシワや異物混入の発生確率を低下させることができるとともに、フィルム巻き直し工数、別途接着剤塗布の工程等が削減でき、生産効率を改善することができ、更に、表面平滑性においても従来の問題を改善することができる。
【図面の簡単な説明】
【図１】本発明に係る熱可塑性樹脂成形品を用いて化粧パネルとした状態を示す部分断面図。
【図２】前記熱可塑性樹脂成形品の詳細断面図。
【図３】前記熱可塑性樹脂成形品の他の例を示す詳細断面図。
【図４】前記熱可塑性樹脂成形品の更に他の例を示す断面図。
【図５】（Ａ）は、目地を設けた場合の前記熱可塑性樹脂成形品断面図、（Ｂ）は、同熱可塑性樹脂成形品の平面図。
【符号の説明】
１０…熱可塑性樹脂成形品、２０…表層、２１…インキ、２２…熱可塑性樹脂基材、２５…プライマー層[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a thermoplastic resin molded product and a method for producing the same, and more particularly, to a thermoplastic resin molded product in which a thermoplastic resin film or sheet is laminated on a thermoplastic resin substrate and a method for producing the same.
[0002]
[Prior art]
2. Description of the Related Art Film-laminated steel sheets having high sharpness and design have been used for exterior materials for home appliances, such as refrigerator doors and fan heater outer plates, and interior wall materials, such as unit baths. The following method is known as a method for producing this film-laminated steel sheet.
(1) Gravure printing is performed on the back surface of a thermoplastic resin film made of a polyester-based resin constituting a surface layer, and a thermoplastic resin film made of a polyvinyl chloride resin or a polyolefin resin or the like is applied to the printed surface with an adhesive. And laminating the steel sheet via an adhesive between the intermediate layer and the steel sheet.
(2) A method of applying gravure printing to a steel sheet and then applying a clear coating on the printing surface.
Among these manufacturing methods, the manufacturing method of (2) requires a printing facility in a coating line, and therefore the manufacturing method of (1) is mainly used (for example, see Japanese Patent Application Laid-Open No. 2000-52486). ).
[0003]
[Problems to be solved by the invention]
However, in the film-laminated steel sheet, there is a phenomenon in which the unevenness of the printing ink appears on the surface layer of the laminated film as orange peel. Therefore, as a countermeasure, a method of forcibly absorbing irregularities of the ink into the intermediate layer by applying heat and pressure when laminating the laminated film to the steel sheet is adopted. However, in this case, the steel sheet must be pre-heated, and there are disadvantages that the manufacturing cost increases due to an increase in the number of manufacturing steps, and that extra energy for hot pressure is used. As another countermeasure, there is a case where a clear layer is provided in the laminated film in order to absorb the unevenness of the ink, but in this case, the disadvantage that the manufacturing cost increases due to the multilayering is inevitable. .
[0004]
Further, apart from the above-mentioned inconvenience of citron skin, there is also an inconvenience caused by the steel sheet itself. For example, as a countermeasure against rust, it is necessary to cover the cross section of the steel sheet with a resin film, and the steps (man-hours) such as bending and drawing work will increase the cost. The handling is poor, such as heavy.
[0005]
In addition, film-laminated steel sheets are generally flat and are hard to have uneven designs. Therefore, in some cases, a concave pattern is formed by cold pressing, or only a surface layer of the laminated film is ground and removed with a cutter to form a concave joint. In this case, a mold is used. It is necessary to increase the cost, and because the film itself is thin (a film thickness of 100 to 250 μm is generally used), high grinding accuracy is required and precise equipment is required. Deep irregularities are also difficult to attach.
[0006]
By the way, a thermoplastic resin molded product in which a laminate of a thermoplastic resin film or sheet is laminated on a thermoplastic resin base material is known as a material applicable to exterior materials for home appliances and interior wall materials for living equipment. . This molded product can be obtained by heat fusion using a method such as extrusion, calender molding, hot press, hot roll press, etc., but in the case of lamination by heat fusion, fusion of the thermoplastic resins used is performed. Lamination of resins having similar softening temperatures is common. Therefore, in such a thermoplastic resin molded product, the pattern printed on the back surface of the film or sheet forming the surface layer is stretched or distorted by the heat at the time of heat fusion, resulting in poor precision, resulting in poor printing accuracy. Causes inconvenience that pattern reproducibility is poor. For example, in the case of an acrylic back print sheet / ABS, which is a laminated sheet of ABS simultaneously extruded with a transparent acrylic sheet, there is a problem that the acrylic sheet is extruded during lamination and the pattern is stretched due to the influence of the ABS resin temperature.
[0007]
In addition, the resins (acrylic, ABS, HIPS, PS, PP, vinyl chloride, etc.) used in the thermoplastic resin molded article molded by the above-mentioned heat fusion generally have solvent resistance, detergent resistance, There is a problem that the chemical resistance is not sufficient. For example, it is known that when the surface of an acrylic resin molded product is wiped with alcohol or thinner, it is dissolved or a solvent crack is generated. Further, in the case of an acrylic resin molded product, there is a problem that the water absorption is high and the dimensional change is large. Further, the polyvinyl chloride film has a possibility of generating dioxin due to combustion, which is a problem in waste disposal.
[0008]
[Object of the invention]
The present invention has been devised in order to improve various inconveniences when laminating a thermoplastic resin sheet or film on a steel sheet, and an object of the present invention is to use a thermoplastic resin base material as a base material, Heat-sealing a laminate of a thermoplastic resin film or sheet with decorative printing applied to the back surface of the surface layer to the material reduces the number of manufacturing steps and ensures sharpness and high quality while ensuring easy handling. An object of the present invention is to provide a thermoplastic resin molded product having a design property and a method for producing the same.
[0009]
Another object of the present invention is to provide a thermoplastic resin molded article having excellent pattern reproducibility, and also having excellent surface performance such as solvent resistance, chemical resistance, detergent resistance and water absorption problem, and a method for producing the same. To provide.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides decorative printing on a surface layer made of a thermoplastic resin film or sheet, and a thermoplastic resin substrate on the printing surface side through an intermediate layer made of the thermoplastic resin film or sheet. A thermoplastic resin molded product laminated on
The surface layer is constituted by a material whose melt softening temperature is higher than the melt softening temperature of the thermoplastic resin substrate by 20 ° C. or more,
The intermediate layer has a configuration in which the melt softening temperature is lower than the melt softening temperature of the surface layer, and the melt softening temperature is in a range of −50 ° C. to + 50 ° C. with respect to the melt softening temperature of the thermoplastic resin base material. I am taking it. With such a configuration, a thermoplastic resin molded article having excellent pattern reproducibility can be provided by fusion utilizing a difference in melting points. Further, since a steel plate is not used as the base material, the various disadvantages described above when the steel plate is used as the base material can be solved.
[0011]
In the present invention, the surface layer is preferably made of PET. This makes it possible to provide a thermoplastic resin molded article having excellent surface performance such as solvent resistance, chemical resistance, detergent resistance, and water absorption problems of the PET film or sheet.
[0012]
Further, a primer layer or an adhesive may be provided between the intermediate layer and the thermoplastic resin substrate. This makes it possible to further improve the adhesive strength between the thermoplastic resin film or sheet and the thermoplastic resin substrate.
[0013]
Furthermore, the present invention relates to a method for producing a thermoplastic resin molded product in which a surface layer made of a thermoplastic resin film or sheet is laminated on a thermoplastic resin substrate via an intermediate layer made of a thermoplastic resin film or sheet,
Perform decorative printing on one surface of the surface layer having a melt softening temperature of 20 ° C. or higher with respect to the melt softening temperature of the thermoplastic resin base material,
The intermediate layer made of a thermoplastic resin having a melt softening temperature lower than the melt softening temperature of the surface layer, and having a melt softening temperature in a range of -50 ° C to + 50 ° C with respect to the melt softening temperature of the thermoplastic resin substrate. Laminated on the printing side,
The method employs a method of fusing the intermediate layer by utilizing heat at the time of molding the thermoplastic resin base material and laminating the intermediate layer on the thermoplastic resin base material.
[0014]
In addition, in this specification, "melt softening temperature" is used about the temperature by the following measuring methods.
In other words, the measurement is performed by placing a coin (a heat-resistant, high-heat-conductivity, non-deformable mark) on a hot plate and heating the hot plate to remove the film or sheet. This is performed by placing the coin on a coin and placing a weight on the coin to apply a constant pressure (about 1 kg / cm ² ). Then, after standing for about 30 seconds, the temperature at which coin marks (matte and dent deformation) start to be formed on the coin contact surface side in the case of a sheet, and the temperature at which the film becomes matte and melts in the case of a film is melt-softened. Temperature.
[0015]
In the thermoplastic resin molded article of the present invention, the surface of the product serving as the surface layer is constituted by a transparent thermoplastic resin film or sheet having a high melt softening temperature, and one or more colors (abstract pattern, geometric fixed pattern, Pattern decoration printing (solid printing, primer printing) is performed by gravure printing, screen printing, ink jet printing, or the like. As the intermediate layer, a thermoplastic resin film or sheet such as PO, PP, or ABS is used. This intermediate layer is dry-laminated on the printing surface side of the surface layer via an adhesive to form a laminated film or sheet. In addition, the intermediate layer is used as a binder with the role of an adhesive, and is subjected to heat fusion by simultaneously laminating a laminated film or sheet at the time of extrusion or calendering of a thermoplastic resin base material, thereby forming a multi-layer plate-like shape. Alternatively, a sheet-shaped thermoplastic resin molded product can be obtained. In this way, by melting the intermediate layer and acting as an adhesive, the unevenness of the laminated film or sheet which may be generated by printing is absorbed, and the sharpness is richer than the decorative steel sheet, and the surface smoothness is excellent. Molded article surface. If necessary, a transparent primer resin, an adhesive or the like may be preliminarily applied to the rear surface of the intermediate layer to further apply the adhesive force (adhesive force), and the laminate may be simultaneously laminated.
[0016]
The surface layer usable in the present invention is typically a thermoplastic resin such as a polyester-based resin, for example, a polyalkylene terephthalate such as PET or PBT. Among them, the most common one is crystalline PET (melting softening temperature of 256 to 267 ° C.), which can effectively exhibit the surface performance of PET, and also melts the surface layer and the thermoplastic resin base material. By effectively utilizing the difference in softening temperature, various problems such as solvent resistance and detergent resistance, which are observed when a resin such as acrylic, ABS, HIPS, PP, PS, and vinyl chloride are employed as a surface layer, and a pattern. The problem that the reproducibility is lowered, the application of the adhesive, the drying step, and the like are separately required can be solved. However, the present invention only requires a difference in the melt softening temperature described above in relation to a thermoplastic resin substrate as a fusion partner, and a blended film or sheet of crystalline PET and amorphous PET, amorphous PET Films or sheets, or flexible PET films or sheets can also be used. In addition, since the difference in melt softening temperature is used, not only does the surface layer have no elongation, there is no matte surface due to heat, and the accuracy and reproducibility of the printed pattern are good. Furthermore, since the molding is performed by simultaneous lamination such as extrusion or calendering, the probability of occurrence of lamination wrinkles and foreign substances can be reduced, and the number of steps for rewinding the film and the step of separately applying an adhesive are reduced. Thus, production efficiency can be improved. Further, at the time of molding, the unevenness is absorbed by the extruded resin, so that the surface smoothness is also improved.
[0017]
Examples of the thermoplastic resin base material in the present invention include, for example, ABS, acrylic, PS, HIPS, PP, non-crystalline polyester, thermoplastic resin containing inorganic filler, thermoplastic resin low foamed product, etc. A translucent, opaque product colored with a coloring agent composed of a pigment and a dye can be arbitrarily selected.
[0018]
In the present invention, the melt softening temperature of the surface layer and the thermoplastic resin substrate, as described above, the difference between the surface layer is required to be higher than the thermoplastic resin substrate by 20 ° C. or more. If the temperature of the extruded resin is not set higher than the melting softening temperature, undissolved substances including undissolved pellets remain, and this must be avoided. It is more preferable that the melt softening temperature of the surface layer with respect to the thermoplastic resin substrate has a difference of 50 ° C. or more. This is to take into account the problem of surface gloss and the variation in extrusion temperature.
[0019]
Further, the present invention uses the heat at the time of extrusion (the resin temperature of the extruded resin) to melt the intermediate layer and the primer layer or the adhesive provided as necessary, and to fuse them to the thermoplastic resin base material. In this case, the melt softening temperature of the intermediate layer in this case is in the range of −50 ° C. to + 50 ° C. as compared with the melt softening temperature of the extruded thermoplastic resin substrate, as described above. Therefore, for example, if the thermoplastic resin substrate has a melt softening temperature of 150 ° C, the intermediate layer may have a melt softening temperature of 100 to 200 ° C. The difference in melt softening temperature between the intermediate layer and the thermoplastic resin substrate is preferably from -20C to + 20C. This is because the intermediate layer must reach a temperature equal to or higher than the melting softening temperature due to the heat of the extruded resin at the time of fusion, and if the extruded resin temperature is too low due to the relationship outside the above range, the adhesiveness is significantly reduced. If the temperature of the extruded resin is too high outside the above range, the pattern is blurred, distorted, or wrinkled before fusion. In addition, it is necessary to consider the variation in the resin temperature of the extruded resin (the resin temperature decreases from the time of extrusion to the time of lamination fusion), and it has been confirmed that the fusion can be performed within the above range. However, as for the relationship between the surface layer and the intermediate layer, it is necessary that the melt softening temperature of the surface layer is higher than the melt softening temperature of the intermediate layer in order to maintain the above-mentioned properties of the surface layer itself. As described above, the present invention solves the above-described various problems by combining the surface layer, the extruded thermoplastic resin base material, the intermediate layer, or the primer and the adhesive used as necessary under the above-mentioned conditions (range). Thus, a thermoplastic resin laminated molded article that can be obtained can be obtained.
[0020]
In the present invention, unlike a film-laminated steel sheet, by using a laminated film or sheet of the thermoplastic resin, it becomes easy to arbitrarily impart a concavo-convex design together with the printable design of the laminated film. Further, since the thickness of the molded product is arbitrary, high precision and precision equipment is not required, and any concave design can be obtained by removing a part of the laminated film and the thermoplastic base material by machining. Furthermore, a mold is not required by taking advantage of the thermoplastic resin, and it becomes easy to provide a concavo-convex design by a method such as hot pressing or vacuum forming after manufacturing a molded product.
[0021]
As shown in FIG. 1, a thermoplastic resin molded product 10 according to the present invention is formed into a sheet and adheres to a surface of a panel base material 11 made of plywood, MDF or the like, such as a reactive hot melt. The laminate is formed via the agent 12, and is used as an exterior material for home electric appliances, an interior wall material such as a unit bath, and the like. As shown in detail in FIG. 2, the thermoplastic resin molded article 10 includes a surface layer 20 made of a thermoplastic resin film or sheet, a printing layer 21 printed on the lower surface side in the drawing with a predetermined ink, and An intermediate layer 23 made of a thermoplastic resin film or sheet laminated on the print layer 21 with an adhesive layer 22 interposed therebetween, and a thermoplastic resin base 25 fused with the intermediate layer 23 as a binder. Further, as shown in FIG. 3, the entire surface of the printing layer 21 is subjected to solid printing 26, and as shown in FIG. 4, a primer layer printed with a gravure roll or the like, or an adhesive layer 27. 5, and further, as shown in FIG. 5, a joint 28 formed by engraving by machining to reach the layer of the thermoplastic resin base material 25, or the like. The degree to which the joint 28 is carved is not particularly limited. However, when forming a joint having a depth reaching the base material 25, if a thermoplastic resin base material having a color different from the concealing color of the intermediate layer is used, a printed pattern and a concave shape, or the color of the intermediate layer and the joint shape are used. It is possible to enhance design such as color.
[0022]
【Example】
Examples of the thermoplastic resin molded product according to the present invention will be described below.
[0023]
[Example 1]
As shown in Table 1 below, a PET film having a melt softening temperature of 225 ° C. was used as a surface layer, printing was performed on the back surface, and solid printing was performed on the entire surface to prevent color unevenness. Then, a PO film having a melt softening temperature of 150 ° C. was laminated as an intermediate layer on the printing surface side via an adhesive. The thermoplastic resin base material to be fused was an opaque ABS resin (melt softening temperature 125 ° C.) colored by adding a pigment. The thermoplastic resin base material was extruded, and simultaneously, the intermediate layer was melted by the heat during the extrusion and laminated to obtain a thermoplastic resin molded product. The appearance of the molded article was extremely good, and the adhesion was also good.
In this embodiment, the overall thickness of the thermoplastic resin molded product is fixed at 2.0 mm. However, since the extrusion molding is used, the thickness can be adjusted arbitrarily. As shown in FIG. 1, the obtained thermoplastic resin molded article was adhered to a panel base made of plywood, MDF, or the like to form a decorative panel. Note that a particle board, an inorganic plate, a metal plate, or the like can be selected as the panel base material.
[0024]
[Example 2]
Molding was performed under the same conditions as in Example 1 except that a primer layer was provided between the intermediate layer and the thermoplastic resin base material. In this example, excellent results in terms of adhesion could be obtained due to the interposition of the primer layer.
[0025]
[Example 3]
A hot-melt adhesive was provided in place of the primer layer in Example 2. Otherwise, molding was performed under the same conditions as in Example 1. Also in this example, excellent results could be obtained in terms of adhesion due to the interposition of the adhesive.
[0026]
[Example 4]
Molding was performed under the same conditions as in Example 1 except that a HIPS resin having a melt softening temperature of 120 ° C. was used as the thermoplastic resin base material. Also in this example, the same appearance and adhesion as in Example 1 could be obtained.
[0027]
[Example 5]
Molding was performed under the same conditions as in Example 2 except that a PP resin having a melt softening temperature of 160 ° C. was used as the thermoplastic resin base material.
[0028]
[Example 6]
While a PBT film having a melt softening temperature of 205 ° C. was used as the surface layer, an ABS resin having a melt softening temperature of 125 ° C. was used as the thermoplastic resin substrate. Otherwise, molding was performed under the same conditions as in Example 1.
[0029]
[Example 7]
The same surface layer as in Example 6 was used, the same intermediate layer and adhesive as in Example 3 were used, and the same thermoplastic resin substrate as in Example 5 was used.
[0030]
Example 8
As the surface layer, a PCT film having a melt softening temperature of 245 ° C. was used, and the same intermediate layer as in Example 1 was used. As the thermoplastic resin substrate, a methacrylic resin having a melt softening temperature of 130 ° C. was used.
[0031]
[Example (Comparative Example) 9]
Molding was performed under the same conditions as in Example 1 except that a PE resin having a melt softening temperature of 85 ° C. was used as the thermoplastic resin base material. In this example, lamination in which the surface layer and the thermoplastic resin substrate were in close contact with each other could not be performed, and therefore, the appearance of the molded product could not be evaluated. This is considered to be due to the fact that the melt softening temperature of the intermediate layer was too high with respect to the melt softening temperature of the thermoplastic resin substrate.
[0032]
[Example (Comparative Example) 10]
While a PVC film having a melt softening temperature of 105 ° C. was used as the intermediate layer, a PC resin having a melt softening temperature of 195 ° C. was used as the thermoplastic resin substrate. Otherwise, molding was performed under the same conditions as in Example 1. In this example, print blurring occurred in the appearance of the molded article. This is considered to be due to the fact that the melt softening temperature of the intermediate layer was too low relative to the melt softening temperature of the thermoplastic resin substrate.
[0033]
[Table 1]

[0034]
As is clear from Table 1, in the thermoplastic resin molded products of Examples 1 to 8 satisfying the conditions of the present invention, the appearance and the adhesion (clearance in the grid test) were good. An attempt was made to forcibly remove the printed layer, but the printed layer was transferred to the surface on the thermoplastic resin substrate side and peeled off.
[0035]
In terms of surface properties, in a surface performance test such as solvent resistance, a surface acrylic product (50 μm PMMA film / ABS sheet) molded under the same conditions was compared, but the surface of the thermoplastic resin sheet according to the present invention was better. Excellent results such as solvent resistance and chemical resistance were shown.
[0036]
In addition, an adhesive (PUR adhesive) was applied to the back surface of the resin substrate of the thermoplastic resin molded article, and was adhered to the panel substrate. To improve adhesion, a method of applying a primer to improve the adhesion, and a method of applying a bonding agent after grinding and roughing the surface of a thermoplastic resin substrate with a wide sander (physical bonding, anchor effect) Adhesion) method could improve the adhesive strength. As a result, all of ABS, HIPS, PP, and methacrylic resin have improved adhesive strength to the panel base material, and decorative panels (treated for use as dwelling-related members such as bathroom panels, kitchen panels, partitions, etc.) It was possible to obtain physical properties without any problem that could be used.
[0037]
【The invention's effect】
As described above, according to the present invention, it is possible to eliminate various inconveniences caused by the film-laminated steel sheet, and to obtain a thermoplastic resin molded article having unique surface performance excellent in reproducibility of a printed pattern. Can be obtained. That is, by laminating the difference in the melting softening temperature in a specific range, there is no elongation of the printed pattern provided on the thermoplastic resin film or sheet surface forming the surface layer, no matte of the surface due to heat, printing The accuracy and reproducibility of the pattern are improved. In addition, since the sheet-shaped thermoplastic resin molded article is not fused to the thermoplastic resin substrate after the molded article is formed but is fused by extrusion (calender molding) simultaneous lamination, laminating wrinkles, In addition to reducing the probability of foreign matter being mixed, the number of steps for rewinding the film and the step of separately applying an adhesive can be reduced, improving production efficiency and improving conventional problems in surface smoothness. can do.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional view showing a state where a decorative panel is formed using a thermoplastic resin molded product according to the present invention.
FIG. 2 is a detailed sectional view of the thermoplastic resin molded product.
FIG. 3 is a detailed sectional view showing another example of the thermoplastic resin molded product.
FIG. 4 is a sectional view showing still another example of the thermoplastic resin molded product.
5A is a cross-sectional view of the thermoplastic resin molded product when joints are provided, and FIG. 5B is a plan view of the thermoplastic resin molded product.
[Explanation of symbols]
10: thermoplastic resin molded product, 20: surface layer, 21: ink, 22: thermoplastic resin base material, 25: primer layer

Claims

A thermoplastic resin molded product obtained by performing decorative printing on a surface layer made of a thermoplastic resin film or sheet and laminating the thermoplastic resin base material via an intermediate layer made of the thermoplastic resin film or sheet on the printing surface side. ,
The surface layer is constituted by a material having a melt softening temperature higher than the melt softening temperature of the thermoplastic resin substrate by 20 ° C. or more,
The intermediate layer is characterized in that the intermediate layer has a melt softening temperature lower than the melt softening temperature of the surface layer and is in a range of −50 ° C. to + 50 ° C. with respect to the melt softening temperature of the thermoplastic resin substrate. Thermoplastic resin molded products.

The thermoplastic resin molded article according to claim 1, wherein the surface layer is made of PET.

The thermoplastic resin molded product according to claim 1 or 2, wherein a primer layer or an adhesive is provided between the intermediate layer and the thermoplastic resin base material.

In a method for producing a thermoplastic resin molded product in which a surface layer made of a thermoplastic resin film or sheet is laminated through an intermediate layer made of a thermoplastic resin film or sheet on a thermoplastic resin substrate,
Perform decorative printing on one surface of the surface layer having a higher melting softening temperature of 20 ° C. or higher than the melting softening temperature of the thermoplastic resin base material,
The intermediate layer made of a thermoplastic resin having a melt softening temperature lower than the melt softening temperature of the surface layer, and having a melt softening temperature in a range of -50 ° C to + 50 ° C with respect to the melt softening temperature of the thermoplastic resin substrate. Laminated on the printing side,
A method for producing a thermoplastic resin molded product, comprising: fusing the intermediate layer using heat generated during molding of the thermoplastic resin substrate and laminating the intermediate layer on the thermoplastic resin substrate.