JP4090581B2

JP4090581B2 - Pictured sheet, injection molding simultaneous painting method, and molded product

Info

Publication number: JP4090581B2
Application number: JP20260798A
Authority: JP
Inventors: 玄竹内
Original assignee: Dai Nippon Printing Co Ltd
Current assignee: Dai Nippon Printing Co Ltd
Priority date: 1998-07-17
Filing date: 1998-07-17
Publication date: 2008-05-28
Anticipated expiration: 2018-07-17
Also published as: JP2000033665A

Description

【０００１】
【発明の属する技術分野】
本発明は、樹脂成形品、特にポリオレフィン樹脂からなる樹脂成形物の表面に密着良く積層できる絵付シートと、その絵付シートを使用した射出成形同時絵付方法、更に、前記絵付シートを表面に積層一体化して得られる加飾成形品に関する。
【０００２】
【従来の技術】
従来から、樹脂成形物の表面を加飾した成形品が各種用途で使用されている。例えば、特公昭５０−１９１３２号公報等に開示の射出成形同時絵付方法では、樹脂成形物の成形と同時にその表面に絵付シートを積層一体化する事で、表面が加飾された成形品が得られる。この様な射出成形同時絵付方法によって、成形品を得る場合、一般的に使用する射出成形樹脂は、アクリル樹脂、ＡＢＳ樹脂、ポリカーボネート樹脂、或いはこれらのポリマーブレンド物が主な樹脂である。
また、安価なポリオレフィン樹脂からなる樹脂成形物の表面を加飾する場合は、予め絵柄の無い成形物を作製し、それに対して絵付け部分に、プライマー処理等の下地処理を施した後、一般的な絵付け方法である水圧転写法などによって、絵付けして、所望の成形品する場合がほとんどである。
【０００３】
【発明が解決しようとする課題】
ところが、上記射出成形同時絵付方法にて射出成形樹脂として列記した、アクリル樹脂、ＡＢＳ樹脂、ポリーカーボネート樹脂等の汎用樹脂は、加工性は良いが、コストが高いと言う欠点がある。そして、ポリプロピレン樹脂等の安価なポリオレフィン樹脂を射出成形樹脂として使用して射出成形同時絵付方法で表面加飾する場合、絵付シートと樹脂成形物との接着剤には、塩素化ポリプロピレンに変成アクリル樹脂を添加した物を使用する事が多かった。しかし、該接着剤では、絵付シートの予備成形時の熱、樹脂射出時の熱、成形品として得られた後の使用環境下での熱、等によって、接着剤が熱劣化し、満足すべき密着性（耐熱密着性）が得られなかった。
この様な事もあって、安価なポリオレフィン樹脂の樹脂成形物表面を加飾する場合は、上述の如く水圧転写法などによって加飾してきた訳である。しかし水圧転写法では、射出成形同時絵付方法に比較して、加飾するに当たり下地処理等の工程数が増え、結果的にコストアップに繋がっる方法であった。
【０００４】
そこで、本発明の課題は、工程的に効率的な射出成形同時絵付方法による場合でも、樹脂成形物、中でも特にポリオレフィン樹脂からなる樹脂成形物の表面を、耐熱密着性良く絵付シートを積層して加飾できる様にする事であり、その為の、絵付シート、射出成形同時絵付方法、そしてその結果得られる成形品を提供する事である。
【０００５】
【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、本発明の絵付シートでは、熱可塑性樹脂からなる基材シート上に、少なくとも接着剤層を有して成り、該接着剤層の樹脂成分である塩素化ポリオレフィン樹脂の塩素含有率が２０〜２４重量％であり、且つ該樹脂の数平均分子量が５００００〜６００００である構成とした。その結果、被着体に上記接着剤層によって積層して、その表面を加飾する場合に、被着体がポリオレフィン樹脂からなる樹脂成形物であっても、耐熱性に優れた密着性が得られる。また、基材シートがアクリル樹脂からなる透明シートの場合には、本発明の絵付シートは、アクリル樹脂を主体とする基材シート上に、バインダーの樹脂がアクリル樹脂と塩化ビニル−酢酸ビニル共重合体との混合物を主成分とする装飾層と、ウレタン樹脂を主成分とするプライマー層と、塩素含有率が２０〜２４重量％であり且つ該樹脂の数平均分子量が５００００〜６００００である塩素化ポリオレフィン樹脂を主成分とする接着剤層がこの順に形成されてなる構成とした。特にポリオレフィン樹脂の樹脂成形物への積層に於いて、耐熱性に優れた密着性が得られる上、基材シートで透明性良い塗装感を付与でき、また装飾層による装飾で豊かな意匠感等を付与できる。
【０００６】
また、本発明の射出成形同時絵付方法は、上記いずれかの絵付シートを、型開き状態にある一対の型の間に、その接着剤層が射出樹脂側を向く様に供給した後、両型を型締めし、両型で形成されるキャビティに流動状態の樹脂を射出して、成形と同時に樹脂成形物の表面に絵付シートを積層した成形品を得る様にした。
その結果、水圧転写法等によらずに、工程的に効率的な射出成形同時絵付方法によって、ポリオレフィン樹脂等からなる樹脂成形物の表面を、その成形と同時に耐熱性に優れた密着力で絵付シートを積層して加飾できる。
【０００７】
また、本発明の成形品は、前記いずれかの絵付シートが、該絵付シートの接着剤層により、ポリオレフィン樹脂からなる樹脂成形物の表面に積層してなる構成とした。その結果、絵付シートと樹脂成形物との密着性は耐熱性に優れたものとなる。
【０００８】
【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。図１は、本発明の絵付シートの形態例のうちの幾つかを例示する断面図、図２は、本発明の射出成形同時絵付方法を説明する概念図、図３は本発明の成形品の形態例のうちの幾つかを例示する断面図である。
【０００９】
〔絵付シート〕
図１（Ａ）に例示する如く、本発明の絵付シートＳの層構成は、熱可塑性樹脂からなる基材シート１上に、少なくとも接着剤層２が積層された構成であり、そして、該接着剤層として特定の樹脂を使用する。すなわち、該接着剤層２の樹脂成分である塩素化ポリオレフィン樹脂の塩素含有率が２０〜２４重量％であり、且つ該樹脂の数平均分子量が５００００〜６００００とする絵付シートである。そして、本発明の絵付シートは基材シート１及び接着剤層２以外の層を有しても良く、例えば、図１（Ｂ）に例示の絵付シートＳの如く、基材シート１上に、装飾層３、プライマー層４、接着剤層２がこの順に積層された構成でも良い。この様な構成とすれば、装飾層による加飾が可能で、なお且つプライマー層により装飾層及び基材シートに使用できる樹脂の選択範囲を広げる事ができる。この様な図１（Ｂ）に例示の構成の絵付シートの具体例としては、例えば、アクリル樹脂を主体とする基材シート１上に、バインダーの樹脂がアクリル樹脂と塩化ビニル−酢酸ビニル共重合体との混合物を主成分とする装飾層３と、ウレタン樹脂を主成分とするプライマー層４と、塩素化ポリオレフィン樹脂を主成分とする接着剤層２がこの順に積層された絵付シートである。
【００１０】
そして、この様な本発明の絵付シートは、ラミネートシートとして、その接着剤層の接着力を利用して、各種被着体に貼着して、その表面を加飾する用途に使用される。本発明の絵付シートを適用する被着体の材質等は特に限定はないが、本発明の絵付シートは特に、ポリプロピレン等のポリオレフィン樹脂からなる被着体に対して、従来に無く優れた密着性それも耐熱密着性を示すので、ポリオレフィン樹脂は、好適な被着体の材料である。この様な例えばポリオレフィン樹脂等の樹脂からなる被着体は、射出成形等で成形した樹脂成形物であるが、その他の手段で所望の形状とした被着体でも良い。
【００１１】
（基材シート）
基材シート１は、熱可塑性樹脂からなるシートであれば、基本的には特に限定はない。この様な熱可塑性樹脂としては、例えば、ポリメチル（メタ）アクリレート、ポリブチル（メタ）アクリレート、メチル（メタ）アクリレート−ブチル（メタ）アクリレート共重合体、メチル（メタ）アクリレート−スチレン共重合体等のアクリル樹脂〔但し、（メタ）アクリレートとは、アクリレート又はメタクリレートの意味〕、塩化ビニル樹脂、ポリスチレン樹脂、ＡＢＳ樹脂（アクリロニトリル−ブタジエン−スチレン共重合体）、ポリカーボネート樹脂、ポリブチレンテレフタレート等のポリエステル樹脂、ポリアミド樹脂、或いは、ポリエチレン、ポリプロピレン、ポリメチルペンテン、ポリブテン、エチレン−プロピレン共重合体、エチレン−プロピレン−ブテン共重合体、オレフィン系熱可塑性エラストマー等のポリオレフィン樹脂等である。基材シートはこれら樹脂のシート（フィルム）の単層又は２層以上の積層体が用いられる。なかでも、透明な基材シートとしてアクリル樹脂を用い、装飾層のバインダーの樹脂が、アクリル樹脂と塩化ビニル−酢酸ビニル共重合体との混合物を主成分とする装飾層で、且つウレタン樹脂を主成分とするプライマー層を介して上記特定組成の接着剤層を積層する組み合わせが、層間密着力の点で、好ましい形態である。アクリル樹脂は透明性に優れ、塗装感等の付与に適している。
なお、基材シートの厚さは、用途に応じて適宜厚さとすれば良く、特に制限は無いが、通常２０〜５００μｍ程度である。
【００１２】
また、絵付シートは、装飾層無しで、基材シートと接着剤層とからなる構成等の絵付シートを用いて、基材シートのみを被着体に積層（もちろん間に接着剤層が介在する）する事もあるが、通常は装飾層も形成した絵付シートとする。また、この様に装飾層無しで、基材シートのみを積層する場合でも、基材シート自体への顔料等の練り込み等によって、基材シート自体を装飾処理しておけば、該基材シート自体が装飾層となって、被着体を加飾する事になる。また、基材シート自体による塗装感の付与でも、被着体を加飾する事になる。
【００１３】
（装飾層）
基材シートに更に装飾層を形成する場合、装飾層としては、基本的には特に制限は無い。装飾層は、印刷インキ或いは塗料で形成する。或いは、金属薄膜等も装飾層として使用できる。装飾層は、接着剤層側（つまり基材シートと接着剤層との間）、或いは接着剤層とは反対側の基材シート面、或いは基材シートの表裏両面、或いは複層構成の基材シート間等に形成できる。但し、接着剤層側とすれば、基材シートを装飾層に対する保護層として使用できる点で好ましい。もちろん、この場合の基材シートは透明（無色又は着色）シートとするが、基材シートを塗装感の付与等の為にも使用できる点で好ましい。
【００１４】
装飾層を印刷インキや塗料で形成する場合、印刷インキ（或いは塗料）のバインダーの樹脂としては、塩素化ポリエチレン、塩素化ポリプロピレン等の塩素化ポリオレフィン、ポリエステル樹脂、ウレタン樹脂、アクリル樹脂、酢酸ビニル樹脂、塩化ビニル−酢酸ビニル共重合体、セルロース系樹脂等を単体、或いは２種以上混合して用いる。なかでも、バインダーの樹脂を、アクリル樹脂と塩化ビニル−酢酸ビニル共重合体との混合物を主成分とした装飾層は、基材シートがアクリル樹脂で、且つウレタン樹脂を主成分とするプライマー層を介して前記特定組成の接着剤層を積層する組み合わは、層間密着力が得られ且つ絵付シートの被着体に対する耐熱密着性も得られる点で、好ましい形態である。ここで、アクリル樹脂としては、前記基材シートの説明のところで列記したものの中から選択する。塩化ビニル−酢酸ビニル共重合体としては、平均重合度３００〜９００程度、酢酸ビニル含有量５〜２０重量％程度のものを用いる。アクリル樹脂と塩化ビニル−酢酸ビニル共重合体との混合比は、アクリル樹脂／塩化ビニル−酢酸ビニル共重合体＝１／９〜９／１（重量比）程度とする。
また、装飾層に用いる着色剤は公知のもので良く、例えばチタン白、カーボンブラック、弁柄、黄鉛、コバルトブルー等の無機顔料、アニリンブラック、フタロシアニンブルー、イソインドリノン、キナクリドン等の有機顔料、アルミニウム箔粉等の金属顔料、二酸化チタン被覆雲母粉末等の真珠光沢（パール）顔料、その他染料等を用いる。
装飾層の模様は、木目模様、石目模様、布目模様、皮絞模様、幾何学図形、文字、記号、或いは全面ベタ等と任意である。
【００１５】
（接着剤層）
本発明の絵付シートでは、接着剤層の樹脂成分として塩素化ポリオレフィン樹脂を用い、なお且つ該樹脂の塩素含有率は２０〜２４重量％の範囲で、且つ該樹脂の数平均分子量が５００００〜６００００の範囲が好ましい。接着剤層に塩素化ポリオレフィン樹脂を使用しただけでは、ポリオレフィン樹脂に対する一応の密着性は得られるが、密着性の耐熱性は得られない。この為、ポリオレフィン樹脂からなる樹脂成形物の表面に絵付シートを積層した成形品は、高温耐熱テスト（例えば１００℃で６０時間）にて、接着剤層が熱に耐えられず、絵付シートに縮みや凹凸が発生する。
しかし、更に該樹脂の塩素含有率及び数平均分子量の両者を、上記特定の範囲とする事によって、耐熱性を備えた優れた密着性が得られる。塩素含有率が２０重量％未満だと、密着性が不十分となり、２４重量％を超えると、射出成形同時絵付方法で被着体に積層する場合に、積層後の成形品の耐熱テスト時の熱で、成形品表面（絵付シート表面）に凹凸を生じ平滑性が低下する。一方、数平均分子量が５００００未満だと、密着は良好だが耐熱テスト時の熱で収縮して、絵付シート表面に皺を生じる。また数平均分子量が６００００を超えると、密着性が不十分となる。
【００１６】
上記の様な塩素化ポリオレフィン樹脂としては、具体的には、塩素化ポリプロピレン、塩素化ポリエチレン等が使用できる。なかでも、塩素化ポリプロピレンは塩素化ポリエチレンに比較してより優れた塗工適性、耐熱密着性を示す点で好ましい。
なお、接着剤層の厚みは使用法に等に応じて適宜厚さとすれば良いが、通常１〜１００μｍ程度である。また、接着剤層の形成方法は特に限定は無いが、通常は、上記樹脂を希釈溶剤で希釈した樹脂液からなるインキ又は塗液として、グラビア印刷、ロールコート等の公知の印刷又は塗工手段により形成する。
なお、接着剤層は、塩素化ポリオレフィン樹脂のみで構成しても良いが、インキ（又は塗液）の印刷（又は塗工）適性等の諸物性を調整、向上させる為に、必要に応じて、体質顔料等の各種添加剤を添加しても良い。
【００１７】
（プライマー層）
本発明の絵付シートでは、必要に応じ、基材シートと接着剤層間、或いは、装飾層と接着剤層間〔図１（Ｂ）参照〕等の層間密着力を向上させる為に、それら層間にプライマー層を設けても良い。プライマー層の樹脂には、特に制限は無く、公知の物の中から適宜選択すれば良い。例えばウレタン樹脂からなるインキ又は塗液でプライマー層は形成すれば良い。特に、装飾層のバインダーの樹脂がアクリル樹脂と塩化ビニル−酢酸ビニル共重合体との混合物を主成分とする場合に、装飾層と接着剤層との間に設ける場合は、プライマー層としてウレタン樹脂を用いると、良好な層間密着力が得られる。
【００１８】
上記ウレタン樹脂としては、２液硬化型ウレタン樹脂、或いは熱可塑性ウレタン樹脂等を使用すれば良い。
２液硬化型ウレタン樹脂は、ポリオールを主剤とし、イソシアネートを架橋剤（硬化剤）とするウレタン樹脂である。ポリオールとしては、分子中に２個以上の水酸基を有するもので、例えばポリエチレングリコール、ポリプロピレングリコール、アクリルポリオール、ポリエステルポリオール、ポリエーテルポリオール、ポリカーボネートポリオール等が用いられる。また、イソシアネートとしては、分子中に２個以上のイソシアネート基を有する多価イソシアネートが用いられる。例えば、２，４−トリレンジイソシアネート、キシレンジイソシアネート、４，４′−ジフェニルメタンジイソシアネート等の芳香族イソシアネート、或いは、１，６−ヘキサメチレンジイソシアネート、イソホロンジイソシアネート、水素添加トリレンジイソシアネート、水素添加ジフェニルメタンジイソシアネート等の脂肪族（乃至は脂環式）イソシアネート、或いはまた、上記各種イソシアネートの付加体、又は多量体を用いる事もできる。例えば、トリレンジイソシアネートの付加体、トリレンジイソシアネート３量体（ｔｒｉｍｅｒ）等がある。
熱可塑性ウレタン樹脂は、２価のポリオールと２価のイソシアネートとをウレタン結合させて得られる線状高分子からなる。
【００１９】
（絵付シートの積層方法）
本発明の絵付シートを、被着体に積層する方法は特に限定はない。例えば、被着体が板材等で被着面が平面であれば、▲１▼加圧ローラーで熱圧を与えて積層する方法でも良い。また被着体が樹脂成形物等の立体物であれば、次の▲２▼や▲３▼等の方法で積層できる。▲２▼特公昭５６−４５７６８号公報（オーバーレイ法）、特公昭６０−５８０１４号公報（真空プレス法）等に記載されるように、被着体表面に絵付シートを、対向又は載置し、被着体側からの真空吸引による圧力差を少なくとも利用して、絵付シートを被着体に積層する、所謂真空成形積層方法。
▲３▼特公昭５０−１９１３２号公報、特公昭４３−２７４８８号公報等に記載されるように、絵付シートを射出成形の雌雄両金型間に配置した後、流動状態の樹脂を型内に射出充填し、樹脂成型物の成形と同時にその表面に絵付シートを積層する、所謂射出成形同時絵付方法。
▲４▼或いは、柱状形状の被着体に対しては、特公昭６１−５８９５号公報、特公平３−２６６６号公報等に記載される様に、円柱、多角柱等の被着体の長軸方向に、化粧シートを供給しつつ、複数の向きの異なるローラーにより、被着体を構成する複数の側面に順次化粧シートを加圧接着して積層してゆく、所謂ラッピング加工方法等でも良い。
【００２０】
〔射出成形同時絵付方法〕
上記した各種積層方法の中でも、絵付シートを被着体に積層する本発明の積層方法としては、射出成形同時絵付方法を採用する。射出成形同時絵付方法によれば、前述した本発明の絵付シートの特定組成からなる接着剤層の特徴を十分に活かして、特にポリオレフィン樹脂からなる被着体を樹脂成形物として射出成形で製造すると同時に１工程で、該被着体表面に絵付シートを積層一体化して加飾する事が出来る、極めて生産効率の良い積層方法となるからである。
すなわち、本発明の射出成形同時絵付方法は、前述した本発明の絵付シートを用いて、所謂射出成形同時絵付方法によって、樹脂成形物の表面に積層して、成形品とする方法である。
【００２１】
なお、本発明の射出成形同時絵付方法は、用いる絵付シートとして前述した本発明の絵付シートを用いる事以外は、従来公知の射出成形同時絵付方法に於ける各種形態をとり得るものである。例えば、絵付シートの予備成形を行う形態でも行わない形態でも、いずれでも良い。また、絵付シートの予熱を行っても良く、行わなくても良い。なお、予備成形時には通常は絵付シートは予熱する。もちろん、絵付シートの絞りが大きい場合は、予備成形を行うのが好ましい。絵付シートの絞りが少ない場合は、射出される流動状態の樹脂の樹脂圧で絵付シートを成形できる。この際、絞りが浅ければ、予備成形無しで樹脂射出と同時に型内に充填される流動状態の樹脂の樹脂圧で絵付シートを成形する事もある。また、絵付シートは予熱せずに射出樹脂の熱を利用する事もある。また、絵付シートを積層する面が平面或いは二次曲面ならば、シート成形無しで積層出来る事もある。また、絵付シートの予備成形は、通常は、射出成形型を真空成形型と兼用して行うが、型間に絵付シートを供給する前に、型外部で別の真空成形型で絵付シートを真空成形する様な予備成形でも良い。なお、真空成形とは真空圧空成形も包含する。
【００２２】
例えば、射出成形型を真空成形型と兼用して絵付シートを予備成形する形態に於ける或る一例として、工程毎に分けて述べれば、次の様な工程からなる射出成形同時絵付方法がある。すなわち、雌雄一対からなる型が型開き状態の時に雌型のパーティング面上に絵付シートを供給するシート供給工程と、前記絵付シートを雌型のパーティング面上に保持固定するクランプ工程と、前記絵付シートを延伸させて雌型のキャビティ面に沿わせる延伸工程（予備成形工程）と、雌型と雄型とを型締めする型締め工程と、雌型と雄型とで形成されるキャビティ内に流動状態の樹脂を注入充填し、樹脂成形物と前記絵付シートとを接触させる射出工程と、射出樹脂が固化した後に雌型と雄型とを離間させる型開き工程と、絵付シートが樹脂成形物に積層された成形品を取り出す成形品取出し工程、をこの順に行う射出成形同時絵付方法である。
【００２３】
ところで、図２は本発明の射出成形同時絵付方法を或る一形態で説明する概念図である。図２に示す形態では、型締めする前に、絵付シートを型間で加熱し軟化させて射出成形型で予備成形した後に、型締めして樹脂を射出する形態である。そこで次に、図２を用いて、本発明の射出成形同時絵付方法を説明する。
【００２４】
先ず、図２（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Ａと、型面に吸引孔１１を有しシートの予備成形型を兼用する型Ｂ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。先ず、型開き状態に於いて両型Ａ、Ｂ間に絵付シートを供給し、型Ｂに絵付シートＳを枠状のクランプ（不図示）で押圧する等して固定する。この際、絵付シートの接着剤層側は、図面右側の射出樹脂側となる様にする事はもちろんである。次いで、図２（Ｂ）の如く、両型間に挿入したヒータ１２で絵付シートを加熱軟化させる（ここでは非接触の輻射加熱の例だが接触加熱でも良い）。そして、図２（Ｃ）の如く吸引孔から吸引して真空成形して、絵付シートを型Ｂのキャビティ面に沿わせ予備成形する。なお、真空成形は圧空も併用する真空圧空成形でも良く、これも包含する。次いで、ヒータ１２を両型間から退避させ、図２（Ｄ）の如く両型を型締めし、図２（Ｅ）の如く両型で形成さ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、樹脂が固化後、型開きして成形品を取り出し、絵付シートの不要部分があれば適宜トリミングすれば、図２（Ｆ）の如く、樹脂成形物５に絵付シートＳが積層された成形品Ｍが得られる。
【００２５】
なお、本発明の射出成形同時絵付方法に於いて、射出成形する樹脂としては、前述の如く基本的には、射出成形同時絵付方法に於ける従来公知のものが使用でき特に制限はない。射出成形樹脂は、製品の要求物性やコスト等に応じて選定される。例えば、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、塩化ビニル樹脂、アクリル樹脂、ポリカーボネート樹脂、或いは、ポリエチレン、ポリプロピレン、ポリブテン、ポリメチルペンテン、エチレン−プロピレン共重合体、エチレン−プロピレン−ブテン共重合体、オレフィン系熱可塑性エラストマー等のポリオレフィン樹脂等である。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の射出成形同時絵付用として従来より知られている材料を使用できる。熱可塑性樹脂は加熱熔融して流動状態で射出し、また硬化性樹脂は適宜加熱して流動状態で射出する。
但し、本発明の射出成形同時絵付方法では、前述した本発明の絵付シートを使用する方法であり、該本発明の絵付シートの特徴を活かして最も効果を奏するのは、ポリプロピレン等の上記各種のポリオレフィン樹脂である。
【００２６】
〔成形品〕
本発明の成形品は、図３（Ａ）及び（Ｂ）に例示する成形品Ｍの如く、前述した本発明の絵付シートＳが、その接着剤層２を介して、ポリオレフィン樹脂からなる樹脂成形物５の表面に積層してなる構成の物である。
また、図３（Ｂ）に示す本発明の成形品Ｍは、絵付シートＳとして、透明な基材シート１上に、装飾層３、プライマー層４、及び接着剤層２がこの順に積層された構成のシートを、その接着剤層２を介して、樹脂成形物５の表面に積層した成形品である。これらに於いて接着剤層２は、前述の如く、塩素含有量及び数平均分子量とした塩素化ポリオレフィン樹脂を主成分とするので、樹脂成形物５に対する絵付シートＳの密着性は耐熱性に優れたものとなる。
【００２７】
図３（Ｂ）に示す構成の成形品の中でも、特に、積層する絵付シートＳの基材シート１がアクリル樹脂を主体とする透明なシートで、この基材シート１の上に、装飾層３がバインダーの樹脂にアクリル樹脂と塩化ビニル−酢酸ビニル共重合体との混合物を主成分として使用する層であり、プライマー層４がウレタン樹脂を主成分とする層であり、そして接着剤層が前述特定の塩素含有量及び数平均分子量とした塩素化ポリオレフィン樹脂を主成分とする層である絵付シートとする構成は、好ましい構成である。透明性に優れたアクリル樹脂からなる基材シートを装飾層に対する保護層及び塗装感付与等の為に使用できる上、絵付シートの樹趣成形物に対する密着性が優れたものとなる。
【００２８】
なお、上記した様な成形品は、通常、絵付シートの積層面が凹凸面等と非平面の立体物である。しかし、本発明の成形品としては、絵付シートの積層面は平面だが他の面が非平面の立体物、積層面が平面となる板状物を排除するものではない。
【００２９】
また、上記した様な本発明の成形品を得るには、絵付シートには本発明の絵付シートを使用するのが必須であるが、絵付シートを樹脂成形物に積層する方法は、特に限定されない。前述した各種積層法等の中から、被着体である樹脂成形物（に於ける絵付シートの被着面の形状）、用意できる製造設備等に応じて、適宜方法を採用すれば良い。但し、前述した本発明の射出成形同時絵付方法を絵付シートの積層方法に採用する事は、立体面へも絵付シートを積層でき、なお且つ成形と積層を同時に１工程で出来、生産効率も良い等の点で、好ましい。
【００３０】
【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。
【００３１】
〔実施例〕
絵付シートとして、透明な１２５μｍ厚のアクリル樹脂フィルム（住友化学工業株式会社製、Ｒ−５２６）を基材シートとして、その片面に、バインダーの樹脂がアクリル樹脂と塩化ビニル−酢酸ビニル共重合体との１対１重量比の混合物で、着色顔料が弁柄、カーボンブラック、黄鉛を主成分とする着色インキで、木目柄の装飾層をグラビア印刷で形成し、更に続いて、２液硬化型ウレタン系樹脂からなるプライマーインキで厚さ１μｍのプライマー層をグラビア印刷で形成し、更に続いて、樹脂成分として塩素化ポリプロピレンを１８．５重量％含有する接着剤（溶液）で、厚さ４μｍの接着剤層をグラビア印刷で形成して、本発明の絵付シートを得た。なお、塩素化ポリプロピレンは、塩素含有率が２２重量％、数平均分子量が５５０００の物を使用した。塩素化ポリプロピレンのこれら組成内容については、比較例と共に表１に纏めて示す。
【００３２】
そして、図２の概念図に示した様な本発明の射出成形同時絵付方法によって、上記絵付シートを樹脂成形物からなる被着体の成形と同時にその表面に積層して、図３（Ｂ）に示す如き層構成の本発明の成形品Ｍを得た。なお、射出成形樹脂としては、ポリプロピレン樹脂（三井東圧化学株式会社製、ＨＩＰ−１４５）を使用した。射出成形同時絵付方法は、絵付シートは射出成形型を真空成形型として、型間に供給後、加熱軟化して真空成形で予備成形する形態によった。また、射出成形金型には、箱型形状のパネルとなる樹脂成形物が得られる金型で、雌型側にシート予備成形の為の吸引孔を有する型を用いた。
【００３３】
得られた成形品は、絵付シートが密着良く樹脂成形物に積層されていた。そして更に、この成形品を、１００℃のオーブン中で６０時間加熱して密着性の耐熱性を評価したところ、成形品には、絵付シートと樹脂成形物との密着不良は発生せず耐熱密着性は良好であった。また、成形品は木目柄で加飾され、表面がアクリル樹脂の為に透明性良い塗装感を有する加飾成形品となった。密着性（初期密着と耐熱密着性）についての評価結果は、比較例と共に表１に纏めて示す。
【００３４】
なお、成形後の密着性は、碁盤目テストとして、成形品表面（絵付シート面）に、２ｍｍ間隔で碁盤目状に縦横に、深さが樹脂成形物にまで達する切り込みを入れて、縦横で１０×１０個の合計１００個の枡目を作った後、セロハン粘着テープ（ニチバン株式会社製、「セロテープ」（登録商標）２４ｍｍ幅、産業用）を２５℃に於いて成形品表面に貼着した後、勢い良く剥がして、絵付シートがテープと共に剥がれるか否かで評価した。剥がれ無きものを○（良好）、剥がれ有りのものを×（不良）とした。
【００３５】
〔比較例１〕
実施例において、接着剤層に用いた塩素化ポリプロピレンについて、数平均分子量を４５０００に変更した（塩素含有率は２２重量％のまま）他は、実施例と同様にして成形品を得た。得られた成形品は、絵付シートが密着良く樹脂成形物に積層されていたが、実施例と同様にして密着性の耐熱性を評価したところ、接着剤層が高熱に耐えられず、成形品の表面（絵付シート）に縮みが発生した。
【００３６】
〔比較例２〕
実施例において、接着剤層に用いた塩素化ポリプロピレンについて、数平均分子量を１０００００に変更した（塩素含有率は２２重量％のまま）他は、実施例と同様にして成形品を得る事を試みた。しかし、接着剤層の接着力が十分に発現しなかった為に、絵付シートは樹脂成形物に密着せず、絵付シートが樹脂成形物に積層された成形品は得られなかった。
【００３７】
〔比較例３〕
実施例において、接着剤層に用いた塩素化ポリプロピレンについて、塩素含有率を２６重量％に変更した（数平均分子量は５５０００のまま）他は、実施例と同様にして成形品を得た。得られた成形品は、絵付シートが密着良く樹脂成形物に積層されていたが、実施例と同様にして密着性の耐熱性を評価したところ、接着剤層が高熱に耐えられず、成形品の表面（絵付シート）に凹凸が発生した。
【００３８】
〔比較例４〕
実施例において、接着剤層に用いた塩素化ポリプロピレンについて、塩素含有率を１８重量％に変更した（数平均分子量は５５０００のまま）他は、実施例と同様にして成形品を得る事を試みた。しかし、接着剤層の接着力が十分に発現しなかった為に、絵付シートは樹脂成形物に密着せず、絵付シートが樹脂成形物に積層された成形品は得られなかった。
【００３９】
【表１】

【００４０】
【発明の効果】
▲１▼本発明の絵付シートによれば、被着体に積層して、その表面を加飾する場合に、被着体が密着し難いポリオレフィン樹脂からなる樹脂成形物であっても、耐熱性に優れた密着性が得られる。
▲２▼また、本発明の絵付シートとして、アクリル樹脂を主体とする透明な基材シート上に、バインダーの樹脂がアクリル樹脂と塩化ビニル−酢酸ビニル共重合体との混合物を主成分とする装飾層と、ウレタン樹脂を主成分とするプライマー層と、塩素化ポリオレフィン樹脂を主成分とする接着剤層がこの順に形成された構成とすれば、更に基材シートによって透明性良い塗装感を付与できる上、また装飾層による装飾で豊かな意匠感等を付与できる。
▲３▼本発明の射出成形同時絵付方法によれば、水圧転写法等によらずに、工程的にも効率的に、ポリオレフィン樹脂からなる樹脂成形物の表面を、その成形と同時に耐熱性に優れた密着力で絵付シートを１工程で積層して加飾できる。
▲４▼本発明の成形品によれば、ポリオレフィン樹脂からなる樹脂成形物と絵付シートとの密着性が耐熱性に優れたものとなる。
【図面の簡単な説明】
【図１】本発明の絵付シートの形態例のうちの幾つかを例示する断面図。
【図２】本発明の射出成形同時絵付方法をその一形態で説明する概念図。
【図３】本発明の成形品の形態例のうちの幾つかを例示する断面図。
【符号の説明】
１基材シート
２接着剤層
３装飾層
４プライマー層
５樹脂成形物
Ａ型（固定型、雄型）
Ｂ型（可動型、雌型）
Ｍ成形品
Ｓ絵付シート[0001]
BACKGROUND OF THE INVENTION
The present invention provides a picture sheet that can be laminated with good adhesion to the surface of a resin molded product, particularly a resin molding made of polyolefin resin, a method of simultaneous injection molding using the picture sheet, and the picture sheet is laminated and integrated on the surface. It is related with the decorative molded product obtained by this.
[0002]
[Prior art]
Conventionally, a molded product in which the surface of a resin molded product is decorated has been used for various purposes. For example, in the injection molding simultaneous painting method disclosed in Japanese Patent Publication No. 50-19132 and the like, a molded product having a decorated surface is obtained by simultaneously laminating and integrating a painting sheet on the surface of the resin molding. It is done. When a molded product is obtained by such an injection molding simultaneous painting method, generally used injection molding resins are acrylic resin, ABS resin, polycarbonate resin, or a polymer blend thereof.
In addition, when decorating the surface of a resin molded product made of an inexpensive polyolefin resin, after preparing a molded product without a pattern in advance and applying a primer treatment or other ground treatment to the painted part, In most cases, painting is performed by a hydraulic transfer method, which is a typical painting method, to obtain a desired molded product.
[0003]
[Problems to be solved by the invention]
However, general-purpose resins such as acrylic resin, ABS resin, and polycarbonate resin listed as injection-molded resins by the above-described simultaneous injection molding method have a good workability but have a drawback of high cost. And when using inexpensive polyolefin resin such as polypropylene resin as the injection molding resin and decorating the surface by the simultaneous injection molding method, the adhesive between the painting sheet and the resin molding is a modified acrylic resin to chlorinated polypropylene. In many cases, a product to which was added was used. However, with the adhesive, the adhesive deteriorates due to heat at the time of preforming the picture sheet, heat at the time of resin injection, heat in the use environment after being obtained as a molded product, etc. Adhesion (heat resistant adhesion) could not be obtained.
For this reason, in the case of decorating the surface of an inexpensive polyolefin resin molded product, it has been decorated by the hydraulic transfer method as described above. However, the hydraulic transfer method is a method that increases the number of processes such as base treatment for decorating as compared with the injection molding simultaneous painting method, resulting in an increase in cost.
[0004]
Therefore, the object of the present invention is to laminate the surface of a resin molded product, particularly a resin molded product made of polyolefin resin, with good heat-resistant adhesion even in the case of a process-effective injection molding simultaneous painting method. It is to be able to decorate, and to that end, it is to provide a sheet with a picture, a method for simultaneous painting with injection molding, and a molded product obtained as a result.
[0005]
[Means for Solving the Problems]
Therefore, in order to solve the above-mentioned problem, in the picture sheet of the present invention, a chlorinated polyolefin resin which has at least an adhesive layer on a base material sheet made of a thermoplastic resin and is a resin component of the adhesive layer The chlorine content is 20 to 24% by weight, and the number average molecular weight of the resin is 50,000 to 60000. As a result, when laminating the adherend with the above adhesive layer and decorating the surface, even if the adherend is a resin molded product made of a polyolefin resin, adhesion with excellent heat resistance is obtained. It is done. In the case where the base sheet is a transparent sheet made of an acrylic resin, the picture sheet of the present invention is formed on the base sheet mainly composed of an acrylic resin, and the binder resin is an acrylic resin and vinyl chloride-vinyl acetate. A decorative layer mainly composed of a mixture with coalescence, a primer layer mainly composed of urethane resin, The chlorine content is 20-24% by weight and the number average molecular weight of the resin is 50,000-60000 A structure in which an adhesive layer mainly composed of a chlorinated polyolefin resin is formed in this order; did . Especially when laminating polyolefin resin to resin moldings, it has excellent heat resistance, can give a good coating feeling with the base sheet, and has a rich design feeling with decoration by the decoration layer. Can be granted.
[0006]
The injection molding simultaneous painting method of the present invention is such that either of the above-mentioned painting sheets is supplied between a pair of molds in an open state so that the adhesive layer faces the injection resin side, and then both molds are used. The mold was clamped, and the resin in a fluid state was injected into the cavity formed by both molds to obtain a molded product in which a picture sheet was laminated on the surface of the resin molded product at the same time as molding.
As a result, the surface of a resin molded product made of polyolefin resin or the like can be painted with an excellent heat resistance at the same time as the molding by a process-effective injection molding simultaneous painting method without using the hydraulic transfer method. Sheets can be stacked and decorated.
[0007]
Further, the molded article of the present invention has a configuration in which any one of the above-mentioned picture sheets is laminated on the surface of a resin molded product made of a polyolefin resin by an adhesive layer of the picture sheet. As a result, the adhesion between the picture sheet and the resin molded product is excellent in heat resistance.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view illustrating some of the embodiments of a picture sheet of the present invention, FIG. 2 is a conceptual diagram illustrating the simultaneous injection molding method of the present invention, and FIG. 3 is a diagram of the molded article of the present invention. It is sectional drawing which illustrates some of the example forms.
[0009]
[Sheet with picture]
As illustrated in FIG. 1A, the layer structure of the picture sheet S of the present invention is a structure in which at least an adhesive layer 2 is laminated on a base material sheet 1 made of a thermoplastic resin. A specific resin is used as the agent layer. That is, the chlorinated polyolefin resin that is a resin component of the adhesive layer 2 has a chlorine content of 20 to 24% by weight, and the number average molecular weight of the resin is 50,000 to 60,000. And the picture sheet of this invention may have layers other than the base material sheet 1 and the adhesive bond layer 2, for example, on the base material sheet 1 like the picture sheet S illustrated in FIG.1 (B), The decoration layer 3, the primer layer 4, and the adhesive layer 2 may be laminated in this order. If it is set as such a structure, the decoration by a decoration layer is possible, and the selection range of resin which can be used for a decoration layer and a base material sheet by a primer layer can be expanded. As a specific example of such a picture sheet having the configuration illustrated in FIG. 1B, for example, a binder resin is made of acrylic resin and vinyl chloride-vinyl acetate co-polymerized on a base sheet 1 mainly composed of acrylic resin. The decorative sheet 3 whose main component is a mixture with coalescence, the primer layer 4 whose main component is urethane resin, and the adhesive layer 2 whose main component is chlorinated polyolefin resin are laminated sheets in this order.
[0010]
And such a sheet | seat with a picture of this invention is used for the use which sticks to various adherends and decorates the surface as a laminate sheet using the adhesive force of the adhesive bond layer. The material of the adherend to which the picture sheet of the present invention is applied is not particularly limited, but the picture sheet of the present invention is particularly excellent in adherence to adherends made of polyolefin resin such as polypropylene. Polyolefin resin is a suitable adherend material because it also exhibits heat-resistant adhesion. Such an adherend made of a resin such as a polyolefin resin is a resin molded product formed by injection molding or the like, but may be an adherend that has a desired shape by other means.
[0011]
(Substrate sheet)
The base sheet 1 is basically not particularly limited as long as it is a sheet made of a thermoplastic resin. Examples of such thermoplastic resins include polymethyl (meth) acrylate, polybutyl (meth) acrylate, methyl (meth) acrylate-butyl (meth) acrylate copolymer, and methyl (meth) acrylate-styrene copolymer. Acrylic resin (however, (meth) acrylate means acrylate or methacrylate), vinyl chloride resin, polystyrene resin, ABS resin (acrylonitrile-butadiene-styrene copolymer), polycarbonate resin, polyester resin such as polybutylene terephthalate, Polyamide resin or polyolefin such as polyethylene, polypropylene, polymethylpentene, polybutene, ethylene-propylene copolymer, ethylene-propylene-butene copolymer, olefinic thermoplastic elastomer It is a down resin, or the like. As the base sheet, a single layer or a laminate of two or more layers of these resin sheets (films) is used. Among them, acrylic resin is used as a transparent base sheet, and the binder resin of the decoration layer is a decoration layer mainly composed of a mixture of acrylic resin and vinyl chloride-vinyl acetate copolymer, and urethane resin is mainly used. A combination in which the adhesive layer having the above specific composition is laminated through a primer layer as a component is a preferable form in terms of interlayer adhesion. Acrylic resin is excellent in transparency and is suitable for imparting a feeling of painting and the like.
In addition, the thickness of a base material sheet should just be suitably thickness according to a use, Although there is no restriction | limiting in particular, Usually, it is about 20-500 micrometers.
[0012]
In addition, the sheet with a picture is laminated with only the base sheet on the adherend without using a decorative layer, and is composed of a base sheet and an adhesive layer (of course, an adhesive layer is interposed between them) ), But usually a picture sheet with a decorative layer. In addition, even when only the base sheet is laminated without the decorative layer as described above, if the base sheet itself is decorated by kneading a pigment or the like into the base sheet itself, the base sheet It itself becomes a decorative layer and decorates the adherend. In addition, the adherend is also decorated by giving a feeling of painting by the base sheet itself.
[0013]
(Decoration layer)
When a decoration layer is further formed on the base sheet, the decoration layer is basically not particularly limited. The decorative layer is formed of printing ink or paint. Or a metal thin film etc. can also be used as a decoration layer. The decorative layer is formed on the adhesive layer side (that is, between the base material sheet and the adhesive layer), the base material sheet side opposite to the adhesive layer, the front and back surfaces of the base material sheet, or the base of the multilayer structure. It can be formed between material sheets. However, the adhesive layer side is preferable in that the base sheet can be used as a protective layer for the decorative layer. Of course, the base sheet in this case is a transparent (colorless or colored) sheet, but it is preferable in that the base sheet can be used for imparting a feeling of painting.
[0014]
When the decorative layer is formed with printing ink or paint, the binder resin of the printing ink (or paint) is chlorinated polyolefin such as chlorinated polyethylene or chlorinated polypropylene, polyester resin, urethane resin, acrylic resin, vinyl acetate resin. , Vinyl chloride-vinyl acetate copolymer, cellulose resin, etc. are used alone or in admixture of two or more. Among them, the decorative layer mainly composed of a mixture of an acrylic resin and a vinyl chloride-vinyl acetate copolymer as a binder resin is a primer layer whose base sheet is an acrylic resin and a urethane resin as a main component. The combination in which the adhesive layer having the specific composition is laminated is a preferable form in that the interlayer adhesion can be obtained and the heat-resistant adhesion to the adherend of the painting sheet can be obtained. Here, the acrylic resin is selected from those listed in the description of the base sheet. As the vinyl chloride-vinyl acetate copolymer, those having an average degree of polymerization of about 300 to 900 and a vinyl acetate content of about 5 to 20% by weight are used. The mixing ratio of the acrylic resin and the vinyl chloride-vinyl acetate copolymer is about acrylic resin / vinyl chloride-vinyl acetate copolymer = 1/9 to 9/1 (weight ratio).
The colorant used in the decorative layer may be a known one, for example, an inorganic pigment such as titanium white, carbon black, petal, chrome, cobalt blue, or an organic pigment such as aniline black, phthalocyanine blue, isoindolinone, or quinacridone. Metal pigments such as aluminum foil powder, pearlescent pigments such as titanium dioxide-coated mica powder, and other dyes are used.
The pattern of the decoration layer is arbitrary, such as a wood grain pattern, a stone pattern, a cloth pattern, a leather pattern, a geometric figure, a character, a symbol, or a solid surface.
[0015]
(Adhesive layer)
In the picture sheet of the present invention, a chlorinated polyolefin resin is used as the resin component of the adhesive layer, the chlorine content of the resin is in the range of 20 to 24% by weight, and the number average molecular weight of the resin is 50,000 to 60,000. The range of is preferable. If only chlorinated polyolefin resin is used for the adhesive layer, temporary adhesion to the polyolefin resin can be obtained, but heat resistance of adhesion cannot be obtained. For this reason, a molded product in which a sheet with a picture is laminated on the surface of a resin molding made of a polyolefin resin, the adhesive layer cannot withstand heat in a high-temperature heat resistance test (eg, 100 ° C. for 60 hours), and shrinks into a picture sheet And unevenness occurs.
However, excellent adhesion with heat resistance can be obtained by setting both the chlorine content and the number average molecular weight of the resin within the specific range. When the chlorine content is less than 20% by weight, the adhesion becomes insufficient. When the chlorine content exceeds 24% by weight, when the laminate is laminated on the adherend by the injection molding simultaneous painting method, Heat causes unevenness on the surface of the molded product (the surface of the sheet with a picture), resulting in a decrease in smoothness. On the other hand, if the number average molecular weight is less than 50000, the adhesion is good, but it shrinks due to heat during the heat resistance test, and wrinkles are generated on the surface of the painted sheet. On the other hand, if the number average molecular weight exceeds 60,000, the adhesion becomes insufficient.
[0016]
Specific examples of the chlorinated polyolefin resin as described above include chlorinated polypropylene and chlorinated polyethylene. Of these, chlorinated polypropylene is preferable in that it exhibits superior coating suitability and heat-resistant adhesion as compared with chlorinated polyethylene.
The thickness of the adhesive layer may be appropriately determined according to the usage method or the like, but is usually about 1 to 100 μm. The method for forming the adhesive layer is not particularly limited, but usually, known printing or coating means such as gravure printing, roll coating, etc. as an ink or coating liquid comprising a resin liquid obtained by diluting the above resin with a diluent solvent. To form.
The adhesive layer may be composed only of chlorinated polyolefin resin, but it is necessary to adjust and improve various physical properties such as printing (or coating) suitability of ink (or coating liquid) as necessary. Various additives such as extender pigments may be added.
[0017]
(Primer layer)
In the picture sheet of the present invention, a primer is provided between the base sheet and the adhesive layer or between the decorative layer and the adhesive layer (see FIG. 1 (B)), if necessary. A layer may be provided. There is no restriction | limiting in particular in resin of a primer layer, What is necessary is just to select suitably from well-known things. For example, the primer layer may be formed of ink or coating liquid made of urethane resin. In particular, when the binder resin of the decoration layer is mainly composed of a mixture of an acrylic resin and a vinyl chloride-vinyl acetate copolymer, when the resin is provided between the decoration layer and the adhesive layer, a urethane resin is used as the primer layer. When is used, good interlayer adhesion can be obtained.
[0018]
As the urethane resin, a two-component curable urethane resin or a thermoplastic urethane resin may be used.
The two-component curable urethane resin is a urethane resin having a polyol as a main component and an isocyanate as a crosslinking agent (curing agent). As the polyol, one having two or more hydroxyl groups in the molecule, for example, polyethylene glycol, polypropylene glycol, acrylic polyol, polyester polyol, polyether polyol, polycarbonate polyol and the like are used. As the isocyanate, a polyvalent isocyanate having two or more isocyanate groups in the molecule is used. For example, aromatic isocyanate such as 2,4-tolylene diisocyanate, xylene diisocyanate, 4,4'-diphenylmethane diisocyanate, or 1,6-hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated diphenylmethane diisocyanate, etc. Aliphatic (or alicyclic) isocyanates, or adducts or multimers of the above-mentioned various isocyanates can also be used. For example, there are tolylene diisocyanate adducts, tolylene diisocyanate trimers, and the like.
The thermoplastic urethane resin is composed of a linear polymer obtained by urethane-bonding a divalent polyol and a divalent isocyanate.
[0019]
(Method of laminating picture sheets)
The method for laminating the painted sheet of the present invention on the adherend is not particularly limited. For example, if the adherend is a plate and the adherend surface is flat, (1) a method of laminating by applying heat pressure with a pressure roller may be used. If the adherend is a three-dimensional object such as a resin molded product, it can be laminated by the following methods (2) and (3). (2) As described in Japanese Patent Publication No. 56-45768 (overlay method), Japanese Patent Publication No. 60-58014 (vacuum press method), etc., a picture sheet is placed opposite or placed on the surface of the adherend. A so-called vacuum forming and laminating method in which a picture sheet is laminated on an adherend using at least a pressure difference caused by vacuum suction from the adherend side.
(3) As described in JP-B-50-19132, JP-B-43-27488, etc., after placing a picture sheet between both injection-male and male molds, the resin in a fluid state is placed in the mold. A so-called injection molding simultaneous painting method in which injection filling is performed and a sheet with a picture is laminated on the surface simultaneously with molding of a resin molding.
(4) Alternatively, for columnar adherends, the length of the adherend such as a cylinder or a polygonal column, as described in Japanese Patent Publication No. 61-5895, Japanese Patent Publication No. 3-2666, etc. A so-called lapping method or the like may be used in which a decorative sheet is supplied in the axial direction, and the decorative sheets are sequentially pressure-bonded and laminated on a plurality of side surfaces constituting the adherend by a plurality of rollers having different directions. .
[0020]
[Injection molding simultaneous painting method]
Among the various laminating methods described above, an injection molding simultaneous painting method is adopted as the laminating method of the present invention in which a painting sheet is laminated on an adherend. According to the injection molding simultaneous painting method, the characteristics of the adhesive layer comprising the specific composition of the painting sheet of the present invention described above are fully utilized, and in particular, an adherend made of a polyolefin resin is produced by injection molding as a resin molded product. This is because, in one step, it becomes a lamination method with extremely high production efficiency, in which a picture sheet can be laminated and integrated on the surface of the adherend and decorated.
That is, the injection molding simultaneous painting method of the present invention is a method in which the above-mentioned painting sheet of the present invention is laminated on the surface of a resin molded product by the so-called injection molding simultaneous painting method to form a molded product.
[0021]
The injection molding simultaneous painting method of the present invention can take various forms in the conventionally known injection molding simultaneous painting method except that the above-described painting sheet of the present invention is used as the painting sheet to be used. For example, either a form in which a picture sheet is preformed or a form in which it is not performed may be used. In addition, the picture sheet may or may not be preheated. In the pre-molding, the picture sheet is usually preheated. Of course, when the drawing sheet has a large aperture, it is preferable to perform preforming. When the drawing sheet has a small aperture, the drawing sheet can be formed by the resin pressure of the injected resin in a fluid state. At this time, if the drawing is shallow, the picture sheet may be molded with the resin pressure of the resin in a fluid state filled in the mold at the same time as the resin injection without pre-molding. Also, the picture sheet may use the heat of the injection resin without preheating. Moreover, if the surface on which the sheet with pictures is laminated is a flat surface or a quadratic curved surface, the sheets may be laminated without forming the sheet. In addition, the pre-forming of a picture sheet is usually performed by using an injection mold as a vacuum mold, but before supplying the picture sheet between the molds, vacuum the picture sheet with another vacuum mold outside the mold. It may be preformed like molding. The vacuum forming includes vacuum / pressure forming.
[0022]
For example, as an example of a form in which an injection mold is also used as a vacuum mold and a picture sheet is preformed, there is an injection molding simultaneous painting method consisting of the following processes as described separately for each process. . That is, a sheet supplying step of supplying a picture sheet on a female parting surface when a pair of male and female is in an open state, a clamping step of holding and fixing the picture sheet on the female parting surface, A stretching step (preliminary molding step) for stretching the picture sheet along the cavity surface of the female mold, a clamping process for clamping the female mold and the male mold, and a cavity formed by the female mold and the male mold An injection process in which a resin in a fluid state is injected and filled therein, the resin molding and the picture sheet are brought into contact, a mold opening process in which the female mold and the male mold are separated after the injection resin is solidified, and the picture sheet is a resin This is an injection molding simultaneous painting method in which a molded product take-out step for taking out a molded product laminated on a molded product is performed in this order.
[0023]
By the way, FIG. 2 is a conceptual diagram illustrating the injection molding simultaneous painting method of the present invention in a certain form. The form shown in FIG. 2 is a form in which a picture sheet is softened by heating between molds and pre-molded with an injection mold before mold clamping, and then the mold is clamped and resin is injected. Then, next, the injection molding simultaneous painting method of the present invention will be described with reference to FIG.
[0024]
First, as shown in FIG. 2A, as an injection mold, a mold A having a runner communicating with an injection nozzle and a gate (gate) and a sheet having suction holes 11 on the mold surface are preformed. A pair of molds of a mold B that also serves as a mold is used. These molds are made of metal such as iron or ceramics. First, a picture sheet is supplied between the molds A and B in the mold open state, and the picture sheet S is fixed to the mold B by pressing it with a frame-shaped clamp (not shown). At this time, it goes without saying that the adhesive layer side of the picture sheet is the injection resin side on the right side of the drawing. Next, as shown in FIG. 2 (B), the picture sheet is heated and softened by the heater 12 inserted between both molds (in this example, non-contact radiant heating, but contact heating may be used). Then, as shown in FIG. 2C, suction is performed through the suction holes and vacuum forming is performed, and the picture sheet is preformed along the cavity surface of the mold B. Note that the vacuum forming may be vacuum / pressure forming using pressure air together, and includes this. Next, the heater 12 is retracted from between the two molds, both molds are clamped as shown in FIG. 2D, and a resin in a fluid state such as a heat-melted state is placed in the cavity formed by both molds as shown in FIG. Fill. Then, after the resin is solidified, the mold is opened and the molded product is taken out. If there is an unnecessary portion of the picture sheet, trimming is appropriately performed. As shown in FIG. 2 (F), the picture sheet S is laminated on the resin molding 5. Product M is obtained.
[0025]
In the injection molding simultaneous painting method of the present invention, as the resin for injection molding, the conventionally known resins in the injection molding simultaneous painting method can be basically used as described above, and there is no particular limitation. The injection molding resin is selected according to the required physical properties and cost of the product. For example, if it is a thermoplastic resin, ABS (acrylonitrile-butadiene-styrene copolymer) resin, styrene resin, vinyl chloride resin, acrylic resin, polycarbonate resin, or polyethylene, polypropylene, polybutene, polymethylpentene, ethylene-propylene Examples thereof include polyolefin resins such as copolymers, ethylene-propylene-butene copolymers, and olefinic thermoplastic elastomers. Moreover, if it is curable resin, the material conventionally known for injection molding simultaneous painting of uncured resin liquids, such as two-component curable resin, for example, urethane resin, unsaturated polyester resin, epoxy resin, etc. Can be used. The thermoplastic resin is melted by heating and injected in a fluid state, and the curable resin is appropriately heated and injected in a fluid state.
However, in the injection molding simultaneous painting method of the present invention, the above-described painting sheet of the present invention is used, and the most effective use of the characteristics of the painting sheet of the present invention is the above-mentioned various types such as polypropylene. Polyolefin resin.
[0026]
〔Molding〕
The molded product of the present invention is a resin molded product in which the above described sheet S of the present invention is made of a polyolefin resin through the adhesive layer 2 as in the molded product M illustrated in FIGS. 3 (A) and 3 (B). It is a thing of the structure formed by laminating | stacking on the surface of the thing 5. FIG.
Moreover, as for the molded article M of this invention shown in FIG.3 (B), the decoration layer 3, the primer layer 4, and the adhesive bond layer 2 were laminated | stacked in this order on the transparent base material sheet 1 as the sheet | seat S with a picture. This is a molded product obtained by laminating a structured sheet on the surface of the resin molded product 5 with the adhesive layer 2 interposed therebetween. In these, since the adhesive layer 2 is mainly composed of a chlorinated polyolefin resin having a chlorine content and a number average molecular weight as described above, the adhesion of the picture sheet S to the resin molded product 5 is excellent in heat resistance. It will be.
[0027]
Among the molded articles having the configuration shown in FIG. 3B, in particular, the base sheet 1 of the picture sheet S to be laminated is a transparent sheet mainly composed of acrylic resin, and the decorative layer 3 is formed on the base sheet 1. Is a layer using a mixture of an acrylic resin and a vinyl chloride-vinyl acetate copolymer as a main component for the resin of the binder, the primer layer 4 is a layer having a urethane resin as a main component, and the adhesive layer is as described above. The structure which makes a sheet | seat with a picture which is a layer which has as a main component the chlorinated polyolefin resin made into specific chlorine content and a number average molecular weight is a preferable structure. A base sheet made of an acrylic resin having excellent transparency can be used for a protective layer for the decorative layer, a feeling of painting, and the like, and the adhesion of the painted sheet to the molded article is excellent.
[0028]
The molded article as described above is usually a three-dimensional object in which the laminated surface of the picture sheet is a non-planar surface such as an uneven surface. However, the molded article of the present invention does not exclude solid objects in which the laminated surface of the picture sheet is flat but the other surface is non-planar, and a plate-like object in which the laminated surface is flat.
[0029]
Moreover, in order to obtain the molded product of the present invention as described above, it is essential to use the painted sheet of the present invention as the painted sheet, but the method of laminating the painted sheet on the resin molded product is not particularly limited. . Of the various laminating methods described above, an appropriate method may be employed depending on the resin molded article (the shape of the adherend surface of the picture sheet in the adherend), the manufacturing equipment that can be prepared, and the like. However, adopting the above-described injection molding simultaneous painting method of the present invention as a method for laminating a painting sheet enables lamination of a painting sheet on a three-dimensional surface, and also allows molding and lamination to be performed in one step at the same time, resulting in good production efficiency. Etc. are preferable.
[0030]
【Example】
Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.
[0031]
〔Example〕
As a sheet with a picture, a transparent 125 μm-thick acrylic resin film (R-526, manufactured by Sumitomo Chemical Co., Ltd.) is used as a base sheet, and on one side, a binder resin is an acrylic resin and a vinyl chloride-vinyl acetate copolymer. A one-to-one weight mixture of the above, and the coloring pigment is a color ink mainly composed of a petal, carbon black, and chrome lead, and a decorative layer with a grain pattern is formed by gravure printing. A primer layer having a thickness of 1 μm is formed by gravure printing with a primer ink made of urethane resin, and subsequently, an adhesive (solution) containing 18.5% by weight of chlorinated polypropylene as a resin component, and having a thickness of 4 μm. The adhesive layer was formed by gravure printing to obtain a picture sheet of the present invention. The chlorinated polypropylene used was one having a chlorine content of 22% by weight and a number average molecular weight of 55,000. These composition contents of chlorinated polypropylene are summarized in Table 1 together with comparative examples.
[0032]
Then, by the simultaneous injection molding picture painting method of the present invention as shown in the conceptual diagram of FIG. 2, the picture sheet is laminated on the surface simultaneously with the molding of the adherend made of the resin molded product, and FIG. A molded product M of the present invention having a layer structure as shown in FIG. In addition, as injection molding resin, polypropylene resin (the Mitsui Toatsu Chemical Co., Ltd. make, HIP-145) was used. The injection molding simultaneous painting method was based on a form in which the painting sheet was supplied between the molds using an injection mold as a vacuum mold, softened by heating and pre-molded by vacuum molding. The injection mold used was a mold for obtaining a resin molded product that would be a box-shaped panel, and a mold having suction holes for sheet preforming on the female mold side.
[0033]
In the obtained molded product, the picture sheet was laminated on the resin molded product with good adhesion. Furthermore, when this molded product was heated in an oven at 100 ° C. for 60 hours to evaluate the heat resistance of the adhesion, the molded product did not have poor adhesion between the picture sheet and the resin molded product, and had a heat resistant adhesion. The property was good. Further, the molded product was decorated with a wood grain pattern, and the surface was made of an acrylic resin, so that it became a decorated molded product having a coating feeling with good transparency. The evaluation results for adhesion (initial adhesion and heat-resistant adhesion) are shown together in Table 1 together with the comparative examples.
[0034]
In addition, the adhesion after molding is determined as a cross-cut test by making cuts that reach the molded product surface vertically and horizontally in a grid pattern at intervals of 2 mm on the surface of the molded product (pictured sheet surface). After making a total of 100 squares of 10 × 10, cellophane adhesive tape (Nichiban Co., Ltd., “Cellotape” (registered trademark) 24 mm width, industrial use) is attached to the surface of the molded product at 25 ° C. After that, it was peeled off vigorously, and the evaluation was made based on whether the picture sheet was peeled off together with the tape. The thing without peeling was set as (circle) (good), and the thing with peeling was set as x (defect).
[0035]
[Comparative Example 1]
In the examples, a molded product was obtained in the same manner as in the examples except that the number average molecular weight of the chlorinated polypropylene used in the adhesive layer was changed to 45000 (the chlorine content remained at 22% by weight). The resulting molded product had a picture sheet laminated with good adhesion to the resin molded product. However, when the heat resistance of adhesion was evaluated in the same manner as in the examples, the adhesive layer could not withstand high heat, and the molded product was Shrinkage occurred on the surface (sheet with picture).
[0036]
[Comparative Example 2]
In the examples, the number average molecular weight of the chlorinated polypropylene used for the adhesive layer was changed to 100000 (the chlorine content remains 22% by weight), and an attempt was made to obtain a molded product in the same manner as in the examples. It was. However, since the adhesive strength of the adhesive layer was not sufficiently developed, the picture sheet did not adhere to the resin molded article, and a molded article in which the picture sheet was laminated on the resin molded article could not be obtained.
[0037]
[Comparative Example 3]
In the examples, a molded product was obtained in the same manner as in the examples except that the chlorine content of the chlorinated polypropylene used in the adhesive layer was changed to 26% by weight (the number average molecular weight remained at 55000). The resulting molded product had a picture sheet laminated with good adhesion to the resin molded product. However, when the heat resistance of adhesion was evaluated in the same manner as in the examples, the adhesive layer could not withstand high heat, and the molded product was Concavities and convexities occurred on the surface (painted sheet).
[0038]
[Comparative Example 4]
In the examples, with respect to the chlorinated polypropylene used in the adhesive layer, except that the chlorine content was changed to 18% by weight (the number average molecular weight remained at 55000), an attempt was made to obtain a molded product in the same manner as in the examples. It was. However, since the adhesive strength of the adhesive layer was not sufficiently developed, the picture sheet did not adhere to the resin molded article, and a molded article in which the picture sheet was laminated on the resin molded article could not be obtained.
[0039]
[Table 1]

[0040]
【The invention's effect】
(1) According to the picture sheet of the present invention, even if it is a resin molded product made of a polyolefin resin that is difficult to adhere to the adherend when it is laminated on the adherend and decorates its surface, Excellent adhesion can be obtained.
(2) Further, as a picture sheet according to the present invention, a decorative material mainly composed of a mixture of an acrylic resin and a vinyl chloride-vinyl acetate copolymer as a binder resin on a transparent base sheet mainly composed of an acrylic resin. If a layer, a primer layer mainly composed of a urethane resin, and an adhesive layer mainly composed of a chlorinated polyolefin resin are formed in this order, it is possible to impart a more transparent coating feeling to the substrate sheet. Moreover, a rich design feeling can be imparted by decoration with a decorative layer.
(3) According to the injection molding simultaneous painting method of the present invention, the surface of a resin molded product made of a polyolefin resin can be made heat resistant at the same time as the molding efficiently without using a hydraulic transfer method or the like. A sheet with a picture can be laminated and decorated in one step with excellent adhesion.
{Circle around (4)} According to the molded article of the present invention, the adhesion between the resin molded product made of polyolefin resin and the sheet with painting is excellent in heat resistance.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating some of the embodiments of a picture sheet according to the present invention.
FIG. 2 is a conceptual diagram illustrating an injection molding simultaneous painting method of the present invention in one form thereof.
FIG. 3 is a cross-sectional view illustrating some of the embodiments of the molded article of the present invention.
[Explanation of symbols]
1 Base sheet
2 Adhesive layer
3 decoration layers
4 Primer layer
5 resin moldings
A type (fixed type, male type)
B type (movable type, female type)
M molded product
S picture sheet

Claims

It has at least an adhesive layer on a base material sheet made of a thermoplastic resin, the chlorine content of a chlorinated polyolefin resin that is a resin component of the adhesive layer is 20 to 24% by weight, and the resin The number-average molecular weight of 50,000 to 60,000 is a sheet with a picture.

On a transparent base sheet mainly composed of an acrylic resin, a decorative layer whose binder resin is a mixture of an acrylic resin and vinyl chloride-vinyl acetate copolymer as a main component, and a primer layer whose main component is a urethane resin When, the adhesive layer having a number average molecular weight of it and said resin chlorine content of 20 to 24% by weight as a main component chlorinated polyolefin resin is from 50,000 to 60,000, which are formed in this order, sheet with pictures.

The picture sheet according to claim 1 or 2 is supplied between a pair of molds in a mold open state so that the adhesive layer faces the injection resin side, and then both molds are clamped to form both molds. Injection molding simultaneous painting method, in which a resin in a fluid state is injected into a cavity to obtain a molded product in which a sheet with a picture is laminated on the surface of the resin molding simultaneously with molding.

A molded product obtained by laminating the picture sheet according to claim 1 or 2 on the surface of a resin molded product made of a polyolefin resin by the adhesive layer.