JP4237835B2

JP4237835B2 - Injection molding simultaneous decorating sheet and injection molding simultaneous decorating method using the same

Info

Publication number: JP4237835B2
Application number: JP20101697A
Authority: JP
Inventors: 和宏須賀; 治雄宮下
Original assignee: Dai Nippon Printing Co Ltd
Current assignee: Dai Nippon Printing Co Ltd
Priority date: 1997-07-11
Filing date: 1997-07-11
Publication date: 2009-03-11
Anticipated expiration: 2017-07-11
Also published as: JPH1134247A

Description

【０００１】
【発明の属する技術分野】
本発明は、射出成形と同時に成形品表面に積層し一体化させる表面加飾用シートに関する。更に詳しくは、成形後の加飾成形品の表面の帯電による、ほこりの付着を防止する射出成形同時加飾用シートと、それを用いた射出成形同時加飾方法に関する。
【０００２】
【従来の技術】
従来より、建築物内装材、什器、自動車や電車等の車両内装材、厨房、箱等の容器等として、表面装飾した樹脂成形品が広く使われている。
このような表面装飾された成形品を製造する方法として、成形品の成形と同時にその外表面に模様等を設ける射出成形同時加飾方法が、従来より各種の態様で行われている。
例えば、特公昭５０−１９１３２号公報では、真空成形用の通気孔を設けた雌型を利用して、基材シートに熱可塑性樹脂シートを用いた加飾シートを、真空成形した後、雌雄両型の型締めを行って、溶融した熱可塑性樹脂を金型のキャビティ内に射出して、成形品の外表面に加飾シートをラミネートして一体化させる方法が開示されている。この態様の射出成形同時加飾方法は、真空成形と射出成形とを組合わせ、加飾シートを成形樹脂表面にラミネートする方法であり、複雑な曲面形状の表面に装飾ができるものである。また、別の態様として、転写タイプの加飾シートを用いて、加飾シートの基材シートのみを剥離除去して、その転写層を成形樹脂表面に転写される方法もある。或いは、真空成形は射出成形型とは異なる別の型で行ったり、真空成形を行わない態様等もある。
この様に、樹脂成形品の成形と同時に、その表面を加飾シートで加飾する射出成形同時加飾方法は、表面装飾処理と樹脂形成とが同時行える為に生産性に優れ、しかも凹凸面への装飾も可能で、用いる加飾シートの柄を変更することで、多様な装飾に対応できる等の利点がある。
【０００３】
【発明が解決しようとする課題】
ところが、上記加飾シートは樹脂からなる為に帯電し易く、作業中はもちろん、得られた加飾成形品の表面も帯電し易かった。このため、作業中の問題では、ゴミやほこりを抱き込んだまま射出成形すれば、製品表面に異物となって現れる事があった。また、加飾成形品では、その表面にゴミやほこりが付着し美観を損ねたり、付着したゴミが擦られれば傷が付く等の問題があった。また、電気製品では、表面帯電による静電気障害により、電気回路の誤動作の原因ともなる。
【０００４】
そこで、帯電防止策として、帯電防止塗料、例えば特開平４−２２０４６９号公報に開示の水溶性イオン導電性樹脂と熱架橋性単量体からなる塗料を、装飾成形品の表面に塗布する技術が考えられる。しかし、塗布による方法では、その作業中の問題として、成形品はその表面に通常は凹凸が有り、塗布では液だれが起き表面の帯電防止層がムラになったり、塗布時のゴミ等の異物混入、塗布面の非鏡面性、乾燥時の熱による成形品の変形等があり好ましくない。また、射出成形同時加飾工程の他に、帯電防止工程が必要で工程数増となる。また、得られた製品の帯電防止層は表面に露出する為、帯電防止層自体の耐久性の他に、帯電防止層により樹脂成形品本来の耐水性、耐薬品性等が低下するという問題がある。
【０００５】
また、例えば、特開平６−３１６０２４号公報に開示の転写シートの様に、加飾シートに帯電防止性能を持たせた物を用いる技術がある。加飾シート自体に帯電防止性能を持たせれば、別工程も必要なく、成形と同時に成形品表面の加飾と帯電防止との両方を一度に行うことができる。しかし、特開平６−３１６０２４号公報に開示の転写シートタイプの加飾シートでは、基材シート上に、帯電防止層、装飾層、接着剤層がこの順に設けられた構成であり、転写後の成形品表面は帯電防止層が露出し、前記塗布の場合と同様に、得られた製品の性能について、帯電防止層自体の耐久性や、帯電防止層により樹脂成形品本来の耐水性、耐薬品性等が低下する問題があり、満足できるものではない。特に、同号公報の帯電防止層は、前記公報同様に、水溶性イオン導電性樹脂と熱架橋性単量体との架橋反応物からなる層であり、耐水性や耐薬品性の問題がある。
【０００６】
また、上記耐水性や耐薬品性の問題は、帯電防止層として樹脂中にカーボンブラックを分散含有させれば、解決するが、帯電防止層が黒く着色し、透明性が得られず、装飾効果を損なう。このカーボンブラックによる問題は、導電性粒子として、カーボンブラックに替えて酸化亜鉛、酸化スズ等の金属酸化物微粒子を用いることによって、透明性はやや改良されるが、若干白色や青色に着色し、満足できる程度ではない。また、微粒子を分散含有させる樹脂自体には導電性が無い為に、射出成形同時加飾で、加飾シートが伸ばされた時に、導電性粒子同士の間隔が開き、導電性能が低下する問題もある。また、透明性の有る導電性層として、例えば酸化インジウム（Ｉｎ₂Ｏ₃）からなる層を帯電防止層として設ける方法も考えられるが、焼成工程が必要であり、熱可塑性樹脂の樹脂シート上には設けることが難しい。また、射出成形同時加飾で、加飾シートが伸ばされた時に、帯電防止層に亀裂が入り、やはり導電性能が低下する問題がある。
【０００７】
【課題を解決する手段】
そこで上記課題を解決する為に本発明の射出成形同時加飾シートは、ラミネートタイプの加飾シートとして、熱可塑性樹脂からなる基材シートに、装飾層を施して成る加飾シートを、雌型と雄型との間に配した後、キャビティに流動状態の樹脂を射出することで、成形品と一体化させる射出成形同時加飾シートにおいて、前記基材シートの表裏両面の少なくとも片面にイオン導電性アミン変性アクリル樹脂と、エポキシ化合物からなる熱架橋性単量体との架橋硬化物よりなる帯電防止層が設けられた構成とした。この結果、後塗装等の別工程も必要なく、成形と同時に立体形状の成形品表面の加飾と帯電防止との両方を一度に行える様にした。また、基材シートの裏面側、つまり装飾層側に帯電防止層を設ける形態では、帯電防止層が加飾成形品表面に露出せず、該表面は、基材シートとなる為に、耐水性や耐薬品性を低下させる事なく、帯電防止性能を付与できる。しかも、前記イオン導電性アミン変性アクリル樹脂と、エポキシ化合物からなる熱架橋性単量体との架橋硬化物よりなる帯電防止層は、エポキシ化合物からなる熱架橋性単量体をイオン導電性アミン変性アクリル樹脂１００重量部に対して、１０〜５０重量部の割合で配合してイオン導電性アミン変性アクリル樹脂をエポキシ化合物からなる熱架橋性単量体と架橋硬化させた架橋硬化物としてあるので、イオン導電性アミン変性アクリル樹脂の耐水性等を向上させる事ができる。
【０００８】
そして、本発明の射出成形同時加飾方法は、上記の射出成形同時加飾シートを、雌型と雄型との間に配した後、キャビティに流動状態の樹脂を射出することで、前記加飾シートを成形品と一体化する方法とした。
【０００９】
以下、本発明の射出成形同時加飾シート、及びそれを用いた射出成形同時加飾方法ついて詳述する。
【００１０】
〔射出成形同時加飾シート〕
先ず、図１は本発明の射出成形同時加飾シートの一形態を例示する断面図であり、の射出成形同時加飾シートＳは、透明な基材シート１の裏側に、帯電防止層２、装飾層３、接着剤層４がこの順に積層された形態を示す。なお、帯電防止層２は、基材シート１の表裏両面の少なくとも片面にあれば良い。また、基材シートに対して装飾層３を施す側は、基材シート１の表裏の少なくとも片面にあれば良く、図１の様に裏面側の他、表面側、或いは表裏両面でも良い。そして、本発明の加飾シートでは、帯電防止層２は、イオン導電性アミン変性アクリル樹脂から構成する。なお、帯電防止層が基材シートの表面側となる構成では、加飾された成形品の表面に露出する為に、帯電防止層を、イオン導電性アミン変性アクリル樹脂と熱架橋性単量体との架橋硬化物から構成すれば、帯電防止層の耐水性、耐久性を向上でき。接着剤層４については、装飾層３、或いは帯電防止層２が射出樹脂と十分な接着力を有する場合は、これを省略しても良い。なお、表面側とは成形品に加飾シートを積層接着後、外部に露出する側を基材シートの表面側と言う。また、成形品に向き合う側を裏面側と言う。
【００１１】
（基材シート）
基材シート１としては、熱可塑性樹脂からなる樹脂シートであれば、特に制限はない。但し、裏面側に装飾層が積層される場合は、透明性のあることが必要となる。用いる樹脂としては例えば、ポリカーボネート樹脂、アクリル樹脂、ＡＢＳ（アクリロニトリル−ブタジエン−スチレン共重合体）、ポリスチレン、ポリプロピレン等のポリオレフィン、ポリアミド樹脂、ポリブチレンテレフタレート等のポリエステル樹脂、塩化ビニル樹脂、或いはオレフィン系熱可塑性エラストマー等が挙げられる。基材シートは、これら樹脂の１種又は２種以上の混合物からなる樹脂層からなる、単層のシート又は共押出し等により２層以上の積層体としたシートを用いる。
なお、基材シートの樹脂中に顔料等の着色剤を練り込んで、基材シートを着色透明、或いは着色不透明としても良い。顔料としては、チタン白、カーボンブラック、群青、弁柄、黄鉛等の無機顔料、キナクリドン、イソインドリノン、フタロシアニンブルー、アニリンブラック等の有機顔料乃至は染料等が用いられる。この他、必要に応じ、炭酸カルシウム、シリカ（二酸化ケイ素）アルミナ（酸化アルミニウム）、硫酸バリウムの様な体質顔料（充填剤）を添加しても良い。
基材シートの厚みは、用途により適宜選択するが、通常は１２〜５００μｍ程度であるが、成形適性などの点から２０〜３００μｍの範囲が好ましい。薄過ぎると加飾シートが伸ばされた時に破れや皺等を生じ易く、厚過ぎると加飾シートの成形性が低下し、またコスト高となる。
【００１２】
なお、射出成形同時加飾シートの耐光性（耐候性）を向上させる場合には、基材シート中に紫外線吸収剤や光安定剤等を添加させることができる。添加は紫外線吸収剤のみでも良いが、光安定剤と併用する方がより効果的である。紫外線吸収剤としては、ベンゾトリアゾール系、ベンゾフェノン系、サリチル酸系等の有機系の紫外線吸収剤の他に、粒径０．２μｍ以下の微粒子状の酸化亜鉛、酸化セリウム、酸化チタン等の無機物も用いることができる。また、光安定剤としては、ビス−（２，２，２，６，６−テトラメチル−４−ピペリジル）セバケート等のヒンダードアミン系ラジカル捕捉剤を用いることができる。添加量は、紫外線吸収剤、光安定剤とも樹脂分全量に対して通常０．５〜１０重量％程度である。こりより少ないと、耐光性向上効果が充分に得られず、またこれよりも多いと着色化したり、或いは特に有機物系の場合は表面にブリードしたりして、多量に入れても効果的に変化がなく好ましくない。
【００１３】
（帯電防止層）
帯電防止層としては、イオン導電性アミン変性アクリル樹脂から構成する。耐水性を向上させる場合は、これに熱架橋性単量体を加えて架橋反応させた架橋硬化物から構成する。特に基材シートの表面側に設ける帯電防止層は、表面に露出する為に、イオン導電性アミン変性アクリル樹脂と熱架橋性単量体との架橋硬化物から構成すると良い。
なお、帯電防止層は、基材シートの表裏両面の少なくとも片面に設けるが、これには、基材シートの表裏両面、表面側のみ、裏面側のみ、の３つの形態がある。これら形態の帯電防止効果は、表裏両面＞表面側のみ＞裏面側のみ、の順に低下する。表面側に設ける形態（表裏両面及び表面側のみ）は、効果は良いが露出する為、耐久性、耐水性、耐薬品性がさほど要求されない用途に用いると良い。裏面側に設ける形態（表裏両面及び裏面側のみ）は、効果は表面側よりも低下するが露出しない為、耐久性、耐水性、耐薬品性が要求されない用途に用いると良い。特に、本発明の様に、ラミネートタイプの射出成形同時加飾シートの場合には、この裏面側に設ける形態は、従来技術で述べた、後塗装や転写シートでは得られない効果が得られる。
この帯電防止層の厚みは１〜１０μｍ程度とする。
【００１４】
上記イオン導電性アミン変性アクリル樹脂としては、側鎖に４級化したアミン、つまり第四アンモニウム塩基を有し末端に重合性ビニル基を有する化合物と、側鎖に水酸基を有し末端に重合性ビニル基を有する化合物と、これら化合物と共重合体可能な、アクリル酸アルキルエステル等のビニルモノマーや、そのオリゴマー等とを、共重合させて得られる共重合体からなるアクリル樹脂である。側鎖に第四アンモニウム塩基を有し末端に重合性ビニル基を有する化合物としては、例えば、ジメチルアミノエチル（メタ）アクリレートの４級化物等がある。側鎖に水酸基を有し末端に重合性ビニル基を有する化合物としては、例えば、２−ヒドロキシエチル（メタ）アクリレート等がある。
【００１５】
前記熱架橋性単量体としては、熱でイオン導電性アミン変性アクリル樹脂を架橋硬化させる事ができる化合物であり、イオン導電性アミン変性アクリル樹脂の水酸基と熱で反応する化合物として、イソシアネート化合物、エポキシ化合物が挙げられる。これら化合物としては、架橋硬化反応を起こさせる為に、それぞれイソシアネート基やエポキシ基を２以上有する化合物を用いる。なお、イソシアネート化合物は空気中水分と反応する為、イソシアネート化合物よりは、エポキシ化合物の方が取扱いが容易である。
イソシアネート化合物としては、例えば、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、トリレンジイソシアネート等のポリイソシアネートがある。
エポキシ化合物としては、例えばポリエチレングリコールジグリシジルエーテル等のポリエポキサイドがある。
【００１６】
熱架橋性単量体は、イオン導電性アミン変性アクリル樹脂１００重量部に対して、１０〜５０重量部の範囲で用いると良い。１０重量部未満の場合は、架橋が少なすぎ密着性、耐久性、耐水性が向上せず、熱架橋性単量体の配合効果が得られない。また、５０重量部を越えると、熱架橋性単量体の割合が多くなり過ぎて、導電性が低下し、所望の帯電防止効果が得られない。また、架橋が強くなり過ぎて、加飾シートの延伸性が低下する。また、無理に成形すると、帯電防止層及びその近傍の層に亀裂が入ってしまう。
なお、もちろんであるが、基材シートの裏面側に帯電防止層を設ける構成では、帯電防止層は露出しないので、帯電防止層の耐水性や耐薬品性、耐久性は必要としないので、イオン導電性アミン変性アクリル樹脂は熱架橋性単量体を用いて架橋硬化物としなくとも良い。但し、密着性向上が必要な場合は熱架橋性単量体を用いた方が良い。
【００１７】
（装飾層）
装飾層は、グラビア印刷、シルクスクリーン印刷、オフセット印刷等の従来公知の方法、材料で絵柄等を印刷した絵柄インキ層、アルミニウム、クロム等の金属を公知の真空蒸着法、スパッタリング法等で部分又は全面に形成した金属薄膜層等である。これらによる絵柄は、大理石や御影石等の石目模様、タイル調模様、煉瓦調模様、木目模様、布目模様、文字、幾何学模様、全面ベタなど任意である。絵柄インキ層用のインキは、バインダー等からなるビヒクル、顔料や染料等の着色剤、これに適宜加える各種添加剤からなる。バインダーには、アクリル樹脂、塩素化ポリオレフィン樹脂、塩素化ポリプロピレン、酢酸ビニル、塩化ビニル−酢酸ビニル共重合体、ポリエステル樹脂、セルロース系樹脂等の熱可塑性樹脂、ポリウレタン樹脂、エポキシ樹脂等の常温又は熱硬化性樹脂等を、これら樹脂の単体、又は２種以上の混合物の形で用いる。顔料又は染料等の着色剤としては、チタン白、カーボンブラック、弁柄、コバルトブルー、黄鉛、フタロシアニンブルー、イソインドリノン、キナクリドン、アルミニウム粉等の金属顔料、真珠光沢（パール）顔料等が用いられる。
【００１８】
（接着剤層）
接着剤層としては、従来公知の感熱型の接着剤を用いることができる。例えば、熱可塑性樹脂、熱硬化性樹脂、アイオノマー等の樹脂が用いられる。樹脂の具体例としては、例えば、エチルセルロース、硝酸セルロース、酢酸セルロース、エチルヒドロキシエチルセルロース、セルロースアセテートプロピオネート等のセルロース誘導体、ポリスチレン、ポリα−メチルスチレン等のスチレン樹脂又はスチレン共重合体、ポリ（メタ）アクリル酸メチル、ポリ（メタ）アクリル酸エチル、ポリ（メタ）アクリル酸ブチル等のアクリル樹脂、ポリ塩化ビニル、ポリ酢酸ビニル、塩化ビニル−酢酸ビニル共重合体、エチレン−ビニルアルコール共重合体、ポリビニルブチラール等のビニル重合体、ロジン、ロジン変性マレイン酸樹脂、ロジン変性フェノール樹脂、重合ロジン等のロジンエステル樹脂、ポリイソプレンゴム、ポリイソブチルゴム、スチレンブタジエンゴム、ブタジエンアクリロニトリルゴム等のゴム系樹脂、クマロン樹脂、ビニルトルエン樹脂、ポリアミド樹脂、ポリ塩素化オレフィン等の、天然又は合成樹脂、各種アイオノマー等の１種又は２種以上の混合物が用いられる。
【００１９】
〔射出成形同時加飾方法〕
次に、上述の様な本発明の射出成形同時加飾シートを用いた、本発明の射出成形同時加飾方法について説明する。本方法にて、図２の断面図に例示の様な、成形品Ｍの表面に加飾シートＳが積層一体化された、帯電防止された加飾製品Ｗが得られる。
本発明の射出成形同時加飾方法は、その加飾シートとして上記射出成形同時加飾シートを用いる方法であり、従来公知の各種形態の射出成形同時加飾方法に対して適用できるものである。
【００２０】
先ず、加飾シートを成形品形状に良好に追従させる為には、射出成形に先立って加飾シートを射出成形型のキャビティ形成面と同形状となるように、真空成形（真空圧空成形も含む）により予備成形を行うことが望ましい。予備成形法としては、射出成形型を真空成形型と兼用して用いて、加飾シートを予備成形する方法、或いは、予め射出成形型とは異なる別の成形型で予備成形し、予備成形された加飾シートを射出成形型に装着する方法がある。通常は前者の方法が多用され、射出成形型としては雌型が通常は用いられる。
もちろん、成形品（型）形状の絞りが浅く凹凸の段差が小であるか、又は凹凸の小さい湾曲形状の場合、或いは加飾シートの成形性（熱可塑性）が充分大きい場合は、この予備成形は省略し、射出樹脂の熱と圧力とによって、加飾シートを射出成形型のキャビティ形成面形状に追従させて、成形しても良い。
【００２１】
加飾シートの予備成形を、射出成形型にて直接行う形態では、用いる射出成形型には、真空成形もできる様に、そのキャビティ形成面やパーティング面に溝や孔等からなる吸引孔が設けられた構造の型を用いる。
射出成形型で真空成形により予備成形を行うには、例えば、型開き状態にある射出成形型に加飾シートを供給設置した後、熱盤（ヒータ）などを用いて加飾シートを加熱軟化させ、次いでキャビティ形成面等に設けた吸引孔を通して加飾シートで密閉されたキャビティ内空気を真空吸引して、加飾シートをキャビティ形成面に沿わせる。熱盤には、加飾シートと密着して接触し、熱伝導にて加熱する接触加熱方式、或いは加飾シートから離れた位置からの赤外線ヒータ等の加熱面からの輻射熱、又は誘電加熱にて加熱する非接触式等の各種方式の加熱手段が使用される。なお、加飾シートの加熱軟化は、加飾シートが型開き状態の型間に供給された後に行う形態の他、型間に供給する前から加熱軟化を開始する形態等もある。
【００２２】
一方、加飾シートの予備成形を、予め射出成形型とは異なる成形型で別途真空成形法により行う場合は、その成形型には、加飾シートを沿わせる射出成形型のキャビティ形成面と同形状（又は逆凹凸形状でも一応は可能）の真空成形型を用いる。そして、加飾シートを上記した熱盤等の加熱手段にて加熱軟化させた後、加飾シートで密閉された型内の空気を真空吸引して、型の内部形状に成形させた後、脱型し、成形された加飾シートを、射出成形型の所定のキャビティ形成面に装着させる。
【００２３】
以下、本発明の射出成形同時加飾方法を図３及び図４を参照しながら説明する。これら図面により、加飾シートを、型開き状態にある雌雄一対の型からなる射出成形型の間に、加飾シートの表側がキャビティ形成面側を向く様に挿入した後、両型を型締めし、両型で形成されたキャビティに、流動状態の樹脂を射出し充填して、樹脂の固化後、型開きして、加飾シートを成形品の表面に積層一体化させた成形品を得る、射出成形同時加飾方法を説明する。なお、本説明では、本発明の射出成形同時加飾方法の一形態として、射出樹脂に熱可塑性樹脂を用い射出成形型を予備成形の真空成形型と兼用する形態の射出成形同時加飾方法を取り上げる。
【００２４】
先ず図３は、型開き状態にある雌雄両型の間に、加飾シートＳが供給された状態である。図面左右方向に往復動作するダイプレート（可動盤）１１には凹形状のキャビティ形成面を有する雌型１３が固定され、他方のダイプレート（固定盤）１２には射出孔を有する雄型１４が固定され、雄型１４の背面には射出ノズル１５が位置する。また、加飾シートを雌型１３のキャビティを密閉する様にその外周でパーティング面に押圧する枠形状の枠体であるシートクランプ１６が、該パーティング面に対向して設けられている。シートクランプ１６は、型間に常時位置し、加飾シートの予備成形時から型開きまでの間は、エアシリンダ等の駆動機構により雌型１３側に前進移動（図面左側方向）して、加飾シートを雌型１３のパーティング面に押圧し、固定する。ダイプレート１１は背面の油圧シリンダ１７の伸縮で往復動作し、型締め時は雌型１３と雄型１４とを圧接して係合し合体させる。なお、図示はしないが雌型１３のキャビティ形成面には真空ポンプ等の真空源に接続された吸引孔が穿孔してある。また、図示はしないが、加飾シートの加熱軟化用の熱盤が型間と型外部の退避位置との間で往復動作する。
【００２５】
そして、この様な装置を用いて射出成形同時加飾するには、先ず、図３の如く、用意した前記構成の本発明の加飾シートＳを、型開き状態の時に雌型１３と雄型１４との間に挿入する。そして、シートクランプ１６で加飾シートを雌型１３のパーティング面に押圧・固定し、そのキャビティを密閉する。次いで、熱盤（不図示）を型間に挿入して加飾シートを加熱軟化させて真空成形し、加飾シートの予備成形を行う。その結果、加飾シートＳは雌型１３のキャビティ形成面に沿った形状に成形される。予備成形は、雌型１３に設けられた吸引孔（不図示）から、そのキャビティ形成面と加飾シートＳ間に形成された空間内の空気を吸気することで、加飾シートＳの表裏に空気圧差を与えて、雌型１３のキャビティ形成面の形状に追従させることで行われる。なお、予備成形は、雌型１３の吸引孔から真空吸気による単純な真空成形以外に、熱盤の加熱面にも通気孔を設け、該加熱面と加飾シート間を密閉空間としておけば、熱盤からの圧搾空気の吹出しを併用して真空圧空成形しても良い。
そして、熱盤を型外に退避した後、油圧シリンダ１７によりピストン（ラム）１８を図面右方向に動かし、予備成形により加飾シートＳがキャビティ形成面に沿ったままの雌型１３を、雄型１４に圧接し係合し、合体させて型締めを行う。そして、雌雄両型で形成されるキャビティに、射出ノズル１５から加熱溶融した樹脂Ｐを雄型の湯口（ゲート）を通して射出し、充填して、射出成形を行う。図４は型締め後に、射出ノズル１５から流動状態の樹脂をキャビティに射出している最中の状態である。そして、熱可塑性樹脂からなる樹脂が冷却により固化した後、雌型１３を図面左方向に移動して雄型から離して型開きして、成形品を型内から取り出せば、図２に例示の様な、加飾シートＳが成形品Ｍの表面に積層し一体化することで、表面が加飾され且つ帯電防止された成形品Ｍからなる加飾成形品Ｗが得られる。
【００２６】
なお、本発明の射出成形同時加飾方法は、成形品の射出成形と同時に加飾シートを成形品表面に積層する方法であり、適用できる射出成形法として、流動状態の樹脂として熱溶融した熱可塑性樹脂を用いる射出成形法が代表的な射出成形法だが、この他、未硬化液状の反応硬化型樹脂（原料）を射出後、化学反応で硬化させる反応性射出成形法（ＲＩＭ成形法）などの射出成形法でも良い。反応性射出成形法では、流動状態の樹脂は必ずしも加熱溶融した樹脂とは限らない。
【００２７】
〔成形樹脂〕
なお、射出成形で用いる樹脂としては、特に限定されず、通常の射出成形であれば、公知の射出成形用樹脂が使用でき、例えば、ポリ塩化ビニル、ポリスチレン、アクリロニトリル−スチレン共重合体、ＡＢＳ樹脂、アクリル樹脂、ポリカーボネート、ポリエチレン、ポリプロピレン等の熱可塑性樹脂を使用できる。また、反応射出成形の場合の（反応硬化型）樹脂としては、硬化剤としてイソシアネートを用いるポリウレタン樹脂、或いは硬化剤としてイソシアネート、有機スルホン酸塩、過酸化ベンゾイル等を用いる不飽和ポリエステル等の樹脂液を使用することができる。
【００２８】
〔その他〕
また、本発明でいう「加飾」とは、単に絵柄や文字、図形等の目視可能な模様を成形品に付与する以外に、目視不可能な模様、あるいは硬質塗膜、導電性等の機能性層を付与することも包含する。目視不可能な模様の例としては、可視光に対しては無色透明で紫外線照射により蛍光を発する蛍光インキで印刷した絵柄等が用いられる。
また、本発明でいう射出成形とは、通常一般の射出成形で用いる「熱熔融した熱可塑性樹脂」を射出する以外に、「室温で溶融状態にある熱硬化又は２液反応硬化型樹脂の未硬化物」を射出する事も包含する。
また、当然であるが、射出成形同時加飾シートは枚葉でも連続帯状の物でも良い。
【００２９】
【実施例】
以下、本発明を実施例及び比較例により更に説明する。
【００３０】
（実施例）
射出成形同時加飾シートとして、厚み１２５μｍの透明なアクリル樹脂シートの裏面側に、イオン導電性アミン変性アクリル樹脂１００重量部に対して熱架橋性単量体としてエチレングリコールジグリシジルエーテルを２５重量部の割合で配合し溶剤希釈により固形分２０ｗｔ％とした塗液を、グラビア印刷して、加熱乾燥し、塗布量１ｇ／ｍ²（固形分）の架橋硬化物からなる帯電防止層を形成した。
次いで、この帯電防止層上に装飾層として、アクリル樹脂と塩化ビニル−酢酸ビニル共重合体との１：１重量比の混合物からなるバインダーに、チタン白、弁柄、黄鉛からなる顔料を添加したインキにて、木目柄をグラビア印刷して装飾層を形成した。
次いで、この装飾層形成面側に接着剤層として、塩化ビニル−酢酸ビニル共重合体からなる接着剤を、全面にグラビア印刷して、乾燥後の塗布量２ｇ／ｍ²の接着剤層を形成して、本発明の射出成形同時加飾シートを得た。
【００３１】
上記加飾シートを、図３及び図４で概説した様な装置を用いて、加飾シートの加熱軟化及び射出成形型による予備成形有りの形態の射出成形同時加飾方法により、接着剤層が施されて無い表面側を、射出成形型のキャビティ形成面側に向くように雌雄両型間に挿入後、予備成形して、射出成形と同時に射出成形品表面に接着した。加飾シートの予備成形は射出成形用の雌型を用いた真空成形で行い、その条件は１５０℃５秒間加熱後、真空引きを開始し、雌型キャビティ形状に真空成形した。また、射出樹脂にはＡＢＳ樹脂を用い、樹脂温度２３０℃、金型温度４０℃の成形条件で成形した。
【００３２】
（比較例１）
実施例において、帯電防止層を基材シートに形成せずに、その他は実施例同様に装飾層、接着剤層を形成して射出成形同時加飾シートを得た。そして、実施例と同一条件の射出成形同時加飾方法で、成形品を得た。
【００３３】
（比較例２）
実施例において、帯電防止層に用いた熱架橋性単量体の配合量を２５重量部から１００重量部に変更した他は、実施例同様に装飾層、接着剤層を形成して射出成形同時加飾シートを得た。そして、実施例と同一条件の射出成形同時加飾方法で、成形品を得た。
【００３４】
上記実施例及び比較例で得られた装飾樹脂成形品について、その性能評価結果を表１に示す。各評価項目は次の様にして評価した。
▲１▼成形性：予備成形時に成形品表面形状へ射出成形同時加飾シートが伸ばされ追従できるか否か、また装飾層等の割れ発生等を、予備成形後の加飾シートを目視観察して評価した。
▲２▼塵付着性：射出成形同時加飾シートと一体化し表面が加飾された成形品を、室内に１月間放置した後の成形品表面への塵付着量を目視判定した。
▲３▼灰付着性：射出成形同時加飾シートと一体化し表面が加飾された成形品を、室温（２２℃）、湿度４０％ＲＨの環境下で、煙草の灰を成形品表面に降り掛けた後、成形品を逆さにして、成形品表面に付着し残った灰の量を目視判定した。
【００３５】
【表１】

【００３６】
表１の様に、実施例では予備成形時に装飾層の割れ（クラック）の発生は無く成形性は良好で、しかも塵や灰の付着は認められなかった。しかし、比較例１では、成形性は良好であったが、帯電防止層が無い為に、塵及び灰が付着し、成形品の外観は実施例に比べ著しく劣るものであった。また、比較例２では塵及び灰の付着は無いものの、帯電防止層の熱架橋性単量体の配合比率が多い為に、帯電防止層の延伸性が劣り、帯電防止層と隣接する装飾層に割れが発生した。
【００３７】
【発明の効果】
本発明の射出成形同時加飾シートによれば、後塗装等の別工程も必要なく、成形品の成形と同時に、成形品表面の凹凸形状に加飾シートを沿わせて積層し一体化することができ、立体形状の成形品の表面加飾と帯電防止との両方を一度に行える。また、基材シートの裏面側に帯電防止層を設ける形態では、帯電防止層が加飾成形品表面に露出せず、該表面は基材シートとなる為に、耐水性や耐薬品性を低下させる事なく、帯電防止性能を付与できる。また、帯電防止層はエポキシ化合物からなる熱架橋性単量体をイオン導電性アミン変性アクリル樹脂１００重量部に対して、１０〜５０重量部の割合で配合してイオン導電性アミン変性アクリル樹脂をエポキシ化合物からなる熱架橋性単量体で架橋硬化させた架橋硬化物とする事で、帯電防止層の耐水性等を向上できる。そして、本発明の射出成形同時加飾方法によれば、表面加飾され且つ帯電防止された成形品を、効率良く製造することができる。
【図面の簡単な説明】
【図１】本発明の射出成形同時加飾シートの一形態を示す断面図。
【図２】本発明の射出成形同時加飾方法で得られる成形品の一例を示す断面図。
【図３】本発明の射出成形同時加飾方法の一形態の概念的説明図：加飾シートを型間に供給した状態。
【図４】同：型締め後に、樹脂を射出している最中の状態。
【符号の説明】
１基材シート
２帯電防止層
３装飾層（絵柄インキ層、金属薄膜層等）
４接着剤層
１１ダイプレート（可動盤）
１２ダイプレート（固定盤）
１３雌型
１４雄型
１５射出ノズル
１６シートクランプ
１７油圧シリンダ
１８ピストン（ラム）
Ｍ成形品
Ｐ樹脂
Ｓ射出成形同時加飾シート
Ｗ加飾成形品[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sheet for surface decoration that is laminated and integrated on the surface of a molded product simultaneously with injection molding. More specifically, the present invention relates to an injection molding simultaneous decorating sheet for preventing dust from adhering to the surface of a decorative molded product after molding, and an injection molding simultaneous decorating method using the same.
[0002]
[Prior art]
Conventionally, resin-molded products with surface decoration have been widely used as building interior materials, furniture, vehicle interior materials such as cars and trains, containers for kitchens, boxes, and the like.
As a method for producing such a surface-decorated molded product, an injection molding simultaneous decorating method in which a pattern or the like is provided on the outer surface simultaneously with molding of a molded product has been conventionally performed in various modes.
For example, in Japanese Patent Publication No. 50-19132, a decorative sheet using a thermoplastic resin sheet as a base sheet is vacuum formed using a female mold provided with a vacuum forming vent, and then both male and female are used. A method is disclosed in which a mold is clamped, a molten thermoplastic resin is injected into a cavity of a mold, and a decorative sheet is laminated on an outer surface of a molded product to be integrated. The injection molding simultaneous decorating method of this aspect is a method of combining vacuum molding and injection molding and laminating the decorative sheet on the surface of the molded resin, and can decorate the surface of a complicated curved surface. As another aspect, there is a method in which only a base sheet of the decorative sheet is peeled and removed using a transfer type decorative sheet, and the transfer layer is transferred to the surface of the molded resin. Alternatively, there is a mode in which the vacuum molding is performed using a different mold from the injection mold or the vacuum molding is not performed.
In this way, the simultaneous injection molding method of decorating the surface with a decorative sheet simultaneously with the molding of a resin molded product is excellent in productivity because surface decoration treatment and resin formation can be performed at the same time, and the uneven surface There are advantages such as being able to handle various decorations by changing the pattern of the decorative sheet to be used.
[0003]
[Problems to be solved by the invention]
However, since the decorative sheet is made of resin, it is easy to be charged, and the surface of the obtained decorative molded product is easily charged as well as during work. For this reason, as a problem during work, if injection molding is carried out while embracing dust and dirt, it may appear as foreign matter on the product surface. In addition, the decorative molded product has problems such as dust and dust adhering to the surface and deteriorating the appearance, and scratching if the attached dust is rubbed. Also, in electrical products, static electricity failure due to surface charging can cause malfunction of electrical circuits.
[0004]
Therefore, as an antistatic measure, there is a technique of applying an antistatic paint, for example, a paint comprising a water-soluble ion conductive resin and a heat-crosslinkable monomer disclosed in JP-A-4-220469 to the surface of a decorative molded product. Conceivable. However, in the method by coating, as a problem during the work, the molded product usually has irregularities on the surface, so that dripping occurs in the coating and the surface antistatic layer becomes uneven, or foreign matter such as dust during coating. This is not preferable because of contamination, non-specularity of the coated surface, and deformation of the molded product due to heat during drying. In addition to the simultaneous injection molding and decorating process, an antistatic process is required, which increases the number of processes. In addition, since the antistatic layer of the obtained product is exposed on the surface, in addition to the durability of the antistatic layer itself, there is a problem that the water resistance, chemical resistance, etc. inherent to the resin molded product are reduced by the antistatic layer. is there.
[0005]
Further, for example, there is a technique of using a decorative sheet having antistatic performance, such as a transfer sheet disclosed in JP-A-6-31624. If the decorative sheet itself has antistatic performance, a separate process is not required, and both the decoration of the surface of the molded article and the antistatic can be performed at the same time as molding. However, the transfer sheet type decorative sheet disclosed in Japanese Patent Laid-Open No. 6-31024 has a structure in which an antistatic layer, a decorative layer, and an adhesive layer are provided in this order on a base sheet, The antistatic layer is exposed on the surface of the molded product, and as in the case of the above application, the performance of the obtained product is about the durability of the antistatic layer itself and the water resistance and chemical resistance inherent to the resin molded product by the antistatic layer. There is a problem that the properties and the like are lowered, which is not satisfactory. In particular, the antistatic layer of the same publication is a layer made of a crosslinking reaction product of a water-soluble ionic conductive resin and a thermally crosslinkable monomer, as in the above publication, and has problems of water resistance and chemical resistance. .
[0006]
In addition, the above water resistance and chemical resistance problems can be solved by dispersing and containing carbon black in the resin as an antistatic layer, but the antistatic layer is colored black, transparency cannot be obtained, and a decorative effect. Damage. The problem with this carbon black is that, by using metal oxide fine particles such as zinc oxide and tin oxide instead of carbon black as the conductive particles, the transparency is slightly improved, but it is slightly colored in white or blue, Not satisfactory. In addition, since the resin itself containing fine particles is not electrically conductive, there is a problem in that when the decorative sheet is stretched by simultaneous injection molding, the spacing between the conductive particles is widened and the conductive performance is lowered. is there. In addition, as a conductive layer having transparency, for example, indium oxide (In ₂ O _Three ) May be provided as an antistatic layer, but a firing step is required, and it is difficult to provide it on a thermoplastic resin sheet. Further, when the decorative sheet is stretched by simultaneous injection molding, the antistatic layer is cracked, and there is a problem that the conductive performance is also lowered.
[0007]
[Means for solving the problems]
Therefore, in order to solve the above-mentioned problems, the injection-molded simultaneous decorating sheet of the present invention is a laminate-type decorating sheet in which a decorative sheet formed by applying a decorative layer to a base material sheet made of a thermoplastic resin is a female mold. In the injection-molded simultaneous decorating sheet that is integrated with the molded product by injecting the resin in a fluid state into the cavity after being disposed between the base sheet and the male mold, at least one side of the front and back surfaces of the base sheet is ionically conductive Amine-modified acrylic resin Cross-linked cured product of heat-crosslinkable monomer comprising epoxy compound An antistatic layer made of Is The configuration was as follows. As a result, there is no need for separate processes such as post-coating, and both the decoration of the surface of the three-dimensional molded product and the antistatic treatment can be performed at the same time as the molding. Further, in the form in which the antistatic layer is provided on the back surface side of the base material sheet, that is, the decorative layer side, the antistatic layer is not exposed on the surface of the decorative molded product, and the surface becomes a base material sheet. Antistatic performance can be imparted without reducing chemical resistance. Moreover, the ion conductive amine-modified acrylic resin Cross-linked cured product of heat-crosslinkable monomer comprising epoxy compound The antistatic layer made of A thermally crosslinkable monomer composed of an epoxy compound is blended at a ratio of 10 to 50 parts by weight with respect to 100 parts by weight of an ion conductive amine-modified acrylic resin Since the cross-linked cured product obtained by cross-linking and curing the ion conductive amine-modified acrylic resin with a heat-crosslinkable monomer composed of an epoxy compound can improve the water resistance of the ion conductive amine-modified acrylic resin.
[0008]
Then, the injection molding simultaneous decorating method of the present invention includes the above-mentioned injection molding simultaneous decorating sheet disposed between a female mold and a male mold, and then injecting a resin in a fluid state into the cavity. The decorative sheet was integrated with the molded product.
[0009]
Hereinafter, the injection molding simultaneous decorating sheet of the present invention and the injection molding simultaneous decorating method using the same will be described in detail.
[0010]
[Injection molding simultaneous decoration sheet]
First, FIG. 1 is a cross-sectional view illustrating an embodiment of an injection-molded simultaneous decorating sheet of the present invention. The injection-molded co-decorated sheet S is formed on the back side of a transparent base sheet 1 with an antistatic layer 2, The decoration layer 3 and the adhesive layer 4 are shown stacked in this order. The antistatic layer 2 may be on at least one side of the front and back surfaces of the base sheet 1. Moreover, the side which gives the decoration layer 3 with respect to a base material sheet should just be on at least one surface of the front and back of the base material sheet 1, and may be the surface side or both front and back surfaces other than a back surface side like FIG. And in the decorating sheet | seat of this invention, the antistatic layer 2 is comprised from an ion conductive amine modified acrylic resin. In the configuration in which the antistatic layer is on the surface side of the base sheet, the antistatic layer is made of an ion conductive amine-modified acrylic resin and a thermally crosslinkable monomer so as to be exposed on the surface of the decorated molded product. Can be improved in water resistance and durability of the antistatic layer. The adhesive layer 4 may be omitted when the decorative layer 3 or the antistatic layer 2 has a sufficient adhesive force with the injection resin. In addition, the surface side refers to the surface side of a base material sheet the side exposed outside after a decorative sheet is laminated and bonded to a molded product. The side facing the molded product is called the back side.
[0011]
(Substrate sheet)
The base sheet 1 is not particularly limited as long as it is a resin sheet made of a thermoplastic resin. However, when a decorative layer is laminated on the back side, it is necessary to have transparency. Examples of the resin to be used include polycarbonate resin, acrylic resin, ABS (acrylonitrile-butadiene-styrene copolymer), polyolefin such as polystyrene and polypropylene, polyamide resin, polyester resin such as polybutylene terephthalate, vinyl chloride resin, or olefinic heat. Examples thereof include a plastic elastomer. As the base material sheet, a single layer sheet or a sheet having a laminate of two or more layers formed by co-extrusion or the like is used.
In addition, a coloring agent such as a pigment may be kneaded into the resin of the base sheet so that the base sheet is colored transparent or colored opaque. As the pigment, inorganic pigments such as titanium white, carbon black, ultramarine, petal, yellow lead, and organic pigments or dyes such as quinacridone, isoindolinone, phthalocyanine blue, and aniline black are used. In addition, extender pigments (fillers) such as calcium carbonate, silica (silicon dioxide) alumina (aluminum oxide), and barium sulfate may be added as necessary.
Although the thickness of a base material sheet is suitably selected according to a use, Usually, it is about 12-500 micrometers, but the range of 20-300 micrometers is preferable from points, such as a moldability. If it is too thin, it tends to cause tears, wrinkles and the like when the decorative sheet is stretched, and if it is too thick, the formability of the decorative sheet decreases and the cost increases.
[0012]
In addition, when improving the light resistance (weather resistance) of an injection molding simultaneous decorating sheet, an ultraviolet absorber, a light stabilizer, etc. can be added in a base material sheet. Addition may be made only with an ultraviolet absorber, but it is more effective to use it together with a light stabilizer. As the ultraviolet absorber, in addition to organic ultraviolet absorbers such as benzotriazole, benzophenone, and salicylic acid, inorganic substances such as fine particle zinc oxide, cerium oxide, and titanium oxide having a particle size of 0.2 μm or less are also used. be able to. As the light stabilizer, a hindered amine radical scavenger such as bis- (2,2,2,6,6-tetramethyl-4-piperidyl) sebacate can be used. The added amount is usually about 0.5 to 10% by weight with respect to the total amount of the resin component for both the ultraviolet absorber and the light stabilizer. If the amount is less than this, the effect of improving the light resistance cannot be obtained sufficiently, and if it is more than this, it will be colored or bleed, especially in the case of organic materials, and even if it is put in a large amount, it will change effectively. It is not preferable because there is no
[0013]
(Antistatic layer)
The antistatic layer is composed of an ion conductive amine-modified acrylic resin. In the case of improving water resistance, it is composed of a crosslinked cured product obtained by adding a heat-crosslinkable monomer to cause a crosslinking reaction. In particular, the antistatic layer provided on the surface side of the base sheet is preferably composed of a crosslinked cured product of an ion conductive amine-modified acrylic resin and a thermally crosslinkable monomer in order to be exposed on the surface.
The antistatic layer is provided on at least one side of the front and back surfaces of the base sheet, and there are three forms, that is, the front and back surfaces of the base sheet, only the front side, and only the back side. The antistatic effect of these forms decreases in the order of both front and back surfaces> only the front side> only the back side. The form provided on the front surface side (both front and back surfaces and only the front surface side) is effective, but is exposed. Therefore, it is preferably used for applications where durability, water resistance, and chemical resistance are not so required. The form provided on the back side (only the front and back sides and the back side) is less exposed than the front side but is not exposed. Therefore, it is preferably used for applications where durability, water resistance and chemical resistance are not required. In particular, in the case of a laminate-type injection-molded simultaneous decorating sheet as in the present invention, the form provided on the back surface side provides an effect that cannot be obtained by post-coating or transfer sheet as described in the prior art.
The antistatic layer has a thickness of about 1 to 10 μm.
[0014]
The ion conductive amine-modified acrylic resin includes a quaternized amine in the side chain, that is, a compound having a quaternary ammonium base and a polymerizable vinyl group at the terminal, and a hydroxyl group in the side chain and polymerizable at the terminal. It is an acrylic resin comprising a copolymer obtained by copolymerizing a compound having a vinyl group, a vinyl monomer such as an alkyl acrylate ester capable of copolymerization with these compounds, and an oligomer thereof. Examples of the compound having a quaternary ammonium base in the side chain and a polymerizable vinyl group at the terminal include a quaternized product of dimethylaminoethyl (meth) acrylate. Examples of the compound having a hydroxyl group in the side chain and a polymerizable vinyl group at the terminal include 2-hydroxyethyl (meth) acrylate.
[0015]
The thermally crosslinkable monomer is a compound that can crosslink and cure the ion conductive amine-modified acrylic resin with heat, and a compound that reacts with the hydroxyl group of the ion conductive amine modified acrylic resin with heat, an isocyanate compound, An epoxy compound is mentioned. As these compounds, compounds each having two or more isocyanate groups and epoxy groups are used in order to cause a crosslinking and curing reaction. Since the isocyanate compound reacts with moisture in the air, the epoxy compound is easier to handle than the isocyanate compound.
Examples of the isocyanate compound include polyisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, and tolylene diisocyanate.
Examples of the epoxy compound include polyepoxides such as polyethylene glycol diglycidyl ether.
[0016]
The thermally crosslinkable monomer is preferably used in the range of 10 to 50 parts by weight with respect to 100 parts by weight of the ion conductive amine-modified acrylic resin. When the amount is less than 10 parts by weight, the amount of cross-linking is so small that adhesion, durability and water resistance are not improved, and the effect of blending the heat-crosslinkable monomer cannot be obtained. On the other hand, if the amount exceeds 50 parts by weight, the proportion of the thermally crosslinkable monomer is excessively increased, the conductivity is lowered, and the desired antistatic effect cannot be obtained. Moreover, bridge | crosslinking becomes strong too much and the drawability of a decorating sheet falls. Moreover, when it shape | molds forcibly, an antistatic layer and the layer of the vicinity will crack.
Of course, in the configuration in which the antistatic layer is provided on the back surface side of the base sheet, the antistatic layer is not exposed, so the water resistance, chemical resistance, and durability of the antistatic layer are not required. The conductive amine-modified acrylic resin may not be a cured cured product using a heat-crosslinkable monomer. However, when it is necessary to improve the adhesion, it is better to use a thermally crosslinkable monomer.
[0017]
(Decoration layer)
The decorative layer is a part of a conventionally known method such as gravure printing, silk screen printing or offset printing, a pattern ink layer printed with a pattern or the like with a material, or a metal such as aluminum or chromium by a known vacuum deposition method, sputtering method or the like. A metal thin film layer formed on the entire surface. The pattern by these is arbitrary, such as a stone pattern such as marble or granite, a tile-like pattern, a brick-like pattern, a wood-grain pattern, a cloth-pattern, a character, a geometric pattern, and a solid pattern. The ink for the pattern ink layer is composed of a vehicle composed of a binder and the like, a colorant such as a pigment and a dye, and various additives appropriately added thereto. Binders include acrylic resins, chlorinated polyolefin resins, chlorinated polypropylene, vinyl acetate, vinyl chloride-vinyl acetate copolymers, polyester resins, cellulose resins and other thermoplastic resins, polyurethane resins, epoxy resins, etc. A curable resin or the like is used in the form of a single substance or a mixture of two or more of these resins. As colorants such as pigments or dyes, titanium white, carbon black, petal, cobalt blue, chrome lead, phthalocyanine blue, isoindolinone, quinacridone, aluminum powder and other metallic pigments, pearlescent (pearl) pigments, etc. are used. It is done.
[0018]
(Adhesive layer)
As the adhesive layer, a conventionally known heat-sensitive adhesive can be used. For example, a resin such as a thermoplastic resin, a thermosetting resin, or an ionomer is used. Specific examples of the resin include cellulose derivatives such as ethyl cellulose, cellulose nitrate, cellulose acetate, ethyl hydroxyethyl cellulose, cellulose acetate propionate, styrene resins such as polystyrene and poly α-methylstyrene, styrene copolymers, poly ( Acrylic resins such as methyl (meth) acrylate, poly (meth) ethyl acrylate and poly (meth) butyl acrylate, polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer , Vinyl polymers such as polyvinyl butyral, rosin, rosin-modified maleic resin, rosin-modified phenolic resin, rosin ester resin such as polymerized rosin, polyisoprene rubber, polyisobutyl rubber, styrene butadiene rubber, butadiene acrylonitrile Rubber-based resins such as Rirugomu, coumarone resins, vinyltoluene resins, polyamide resins, such as poly-chlorinated olefins, natural or synthetic resin, one or more mixtures of such as various ionomers are used.
[0019]
[Injection molding simultaneous decoration method]
Next, the injection molding simultaneous decorating method of the present invention using the injection molding simultaneous decorating sheet of the present invention as described above will be described. With this method, an antistatic decorative product W in which the decorative sheet S is laminated and integrated on the surface of the molded product M as illustrated in the cross-sectional view of FIG. 2 is obtained.
The injection molding simultaneous decorating method of the present invention is a method using the above-mentioned injection molding simultaneous decorating sheet as the decorating sheet, and can be applied to conventionally known various forms of injection molding simultaneous decorating methods.
[0020]
First, in order to make the decorative sheet follow the shape of the molded article satisfactorily, vacuum forming (including vacuum / pneumatic forming) so that the decorative sheet has the same shape as the cavity forming surface of the injection mold prior to injection molding. It is desirable to perform preforming by the above method. As a pre-molding method, an injection mold is also used as a vacuum mold, and a decorative sheet is pre-molded. Alternatively, a pre-mold is performed in advance by another mold different from the injection mold. There is a method of attaching the decorative sheet to the injection mold. Usually, the former method is frequently used, and a female die is usually used as an injection mold.
Of course, if the shape of the molded product (mold) is shallow and the steps of the unevenness are small, or the curved shape is small in unevenness, or if the formability (thermoplasticity) of the decorative sheet is sufficiently large, this preforming May be omitted, and the decorative sheet may be molded by following the cavity forming surface shape of the injection mold by the heat and pressure of the injection resin.
[0021]
In the form in which the decorative sheet is preformed directly by the injection mold, the injection mold to be used has suction holes made of grooves, holes, etc. on its cavity forming surface and parting surface so that vacuum forming can be performed. Use the type of structure provided.
In order to perform preliminary molding by vacuum molding with an injection mold, for example, after supplying the decorative sheet to the injection mold in the mold open state, the decorative sheet is heated and softened using a heating plate (heater) or the like. Then, the air in the cavity sealed with the decorating sheet is vacuum-sucked through the suction holes provided in the cavity forming surface and the like, and the decorating sheet is placed along the cavity forming surface. The heating plate is in close contact with the decorative sheet and heated by heat conduction, or by radiant heat from a heating surface such as an infrared heater from a position away from the decorative sheet, or by dielectric heating. Various types of heating means such as a non-contact type for heating are used. The heat softening of the decorative sheet may be performed after the decorative sheet is supplied between the molds in the mold open state, or may be the form in which the heat softening is started before being supplied between the molds.
[0022]
On the other hand, when preforming the decorative sheet is performed in advance by a vacuum forming method using a mold different from the injection mold, the mold has the same cavity forming surface as the injection mold along which the decorative sheet is placed. Use a vacuum mold with a shape (or even a reverse uneven shape). Then, after the decorative sheet is heated and softened by heating means such as the above-described hot platen, the air in the mold sealed with the decorative sheet is vacuum-sucked to be molded into the internal shape of the mold, and then removed. The molded decorative sheet is molded and attached to a predetermined cavity forming surface of the injection mold.
[0023]
Hereinafter, the injection molding simultaneous decorating method of the present invention will be described with reference to FIGS. According to these drawings, the decorative sheet is inserted between an injection mold composed of a pair of male and female molds in the mold open state so that the front side of the decorative sheet faces the cavity forming surface side, and then both molds are clamped. Then, a resin in a fluid state is injected and filled into the cavity formed by both molds, and after the resin is solidified, the mold is opened to obtain a molded product in which the decorative sheet is laminated and integrated on the surface of the molded product. The injection molding simultaneous decoration method will be described. In this description, as one form of the injection molding simultaneous decorating method of the present invention, an injection molding simultaneous decorating method in which a thermoplastic resin is used as the injection resin and the injection mold is also used as a preformed vacuum mold. take up.
[0024]
First, FIG. 3 shows a state in which the decorative sheet S is supplied between the male and female molds in the mold open state. A female plate 13 having a concave cavity forming surface is fixed to a die plate (movable platen) 11 that reciprocates in the horizontal direction of the drawing, and a male die 14 having an injection hole is fixed to the other die plate (fixed platen) 12. The injection nozzle 15 is positioned on the back surface of the male mold 14. Further, a sheet clamp 16 that is a frame-shaped frame body that presses the decorative sheet against the parting surface at the outer periphery so as to seal the cavity of the female mold 13 is provided to face the parting surface. The sheet clamp 16 is always located between the molds, and is moved forward (to the left in the drawing) by the drive mechanism such as an air cylinder (from the left side of the drawing) between the pre-molding of the decorative sheet and the mold opening. The decorative sheet is pressed against the parting surface of the female mold 13 and fixed. The die plate 11 reciprocates due to the expansion and contraction of the hydraulic cylinder 17 on the back surface, and when the mold is clamped, the female mold 13 and the male mold 14 are pressed and engaged to be united. Although not shown, a suction hole connected to a vacuum source such as a vacuum pump is formed in the cavity forming surface of the female die 13. Although not shown, a heating plate for heating and softening the decorative sheet reciprocates between the molds and a retracted position outside the molds.
[0025]
In order to simultaneously decorate by injection molding using such an apparatus, first, as shown in FIG. 3, the prepared decorative sheet S of the present invention having the above-described configuration is subjected to a female mold 13 and a male mold when the mold is opened. 14 is inserted. Then, the decorative sheet is pressed and fixed to the parting surface of the female mold 13 with the sheet clamp 16 to seal the cavity. Next, a hot platen (not shown) is inserted between the molds, the decorative sheet is heated and softened, vacuum-formed, and the decorative sheet is preformed. As a result, the decorative sheet S is formed into a shape along the cavity forming surface of the female mold 13. The preforming is performed on the front and back of the decorative sheet S by sucking air in the space formed between the cavity forming surface and the decorative sheet S from a suction hole (not shown) provided in the female mold 13. The air pressure difference is applied to follow the shape of the cavity forming surface of the female mold 13. In addition to the simple vacuum forming by vacuum suction from the suction hole of the female mold 13, the pre-forming is provided with a vent hole on the heating surface of the heating plate, and a space between the heating surface and the decorative sheet is set as a sealed space. Vacuum / pressure forming may be performed by using compressed air blowing from the hot platen.
Then, after the hot platen is moved out of the mold, the piston (ram) 18 is moved rightward in the drawing by the hydraulic cylinder 17, and the female mold 13 with the decorative sheet S along the cavity forming surface is moved by the pre-molding. The mold 14 is pressed and engaged, and united to perform clamping. Then, the resin P heated and melted from the injection nozzle 15 is injected into a cavity formed by both male and female molds through a male pouring gate (gate) and filled to perform injection molding. FIG. 4 shows a state in which resin in a fluid state is being injected from the injection nozzle 15 into the cavity after mold clamping. Then, after the resin made of the thermoplastic resin is solidified by cooling, the female mold 13 is moved in the left direction of the drawing, separated from the male mold and opened, and the molded product is taken out from the mold. By decorating and integrating such a decorative sheet S on the surface of the molded product M, a decorative molded product W made up of the molded product M whose surface is decorated and antistatic is obtained.
[0026]
The simultaneous injection molding method of the present invention is a method of laminating a decorative sheet on the surface of a molded product at the same time as injection molding of the molded product. As an applicable injection molding method, heat melted as a resin in a fluid state The injection molding method using a plastic resin is a typical injection molding method. In addition, a reactive injection molding method (RIM molding method) in which an uncured liquid reaction-curing resin (raw material) is injected and then cured by a chemical reaction, etc. The injection molding method may be used. In the reactive injection molding method, the resin in a fluid state is not necessarily a resin melted by heating.
[0027]
[Molded resin]
The resin used in the injection molding is not particularly limited, and a known injection molding resin can be used as long as it is a normal injection molding. For example, polyvinyl chloride, polystyrene, acrylonitrile-styrene copolymer, ABS resin Thermoplastic resins such as acrylic resin, polycarbonate, polyethylene, and polypropylene can be used. In addition, as a (reaction curable) resin in the case of reaction injection molding, a polyurethane resin using isocyanate as a curing agent, or a resin liquid such as unsaturated polyester using isocyanate, organic sulfonate, benzoyl peroxide or the like as a curing agent Can be used.
[0028]
[Others]
In addition, “decoration” as used in the present invention refers to a pattern that is not visible, or a function such as a hard coating film, conductivity, etc., in addition to simply imparting a visible pattern such as a pattern, character, or figure to a molded product. It also includes providing a sex layer. As an example of a pattern that cannot be visually observed, a pattern printed with fluorescent ink that is colorless and transparent with respect to visible light and emits fluorescence when irradiated with ultraviolet rays is used.
In addition, the injection molding referred to in the present invention means “other than the injection of“ thermo-melted thermoplastic resin ”that is usually used in general injection molding” Injecting a “cured product” is also included.
Needless to say, the injection-molded simultaneous decorating sheet may be a sheet or a continuous strip.
[0029]
【Example】
Hereinafter, the present invention will be further described with reference to Examples and Comparative Examples.
[0030]
(Example)
25 parts by weight of ethylene glycol diglycidyl ether as a thermally crosslinkable monomer for 100 parts by weight of ion-conductive amine-modified acrylic resin on the back side of a transparent acrylic resin sheet having a thickness of 125 μm as a simultaneous decorative sheet for injection molding A coating liquid blended at a ratio of 20 wt% by dilution with a solvent was subjected to gravure printing, heat drying, and a coating amount of 1 g / m. ² An antistatic layer made of a crosslinked cured product (solid content) was formed.
Next, as a decorative layer on this antistatic layer, a pigment made of titanium white, petiole and chrome lead is added to a binder made of a 1: 1 weight ratio mixture of acrylic resin and vinyl chloride-vinyl acetate copolymer. The decorative layer was formed by gravure printing the wood grain pattern with the ink.
Next, an adhesive made of a vinyl chloride-vinyl acetate copolymer is gravure printed on the entire surface as an adhesive layer on the decorative layer forming surface side, and the coating amount after drying is 2 g / m. ² The adhesive layer was formed to obtain the injection-molded simultaneous decorating sheet of the present invention.
[0031]
Using the apparatus as outlined in FIG. 3 and FIG. 4, the above decorative sheet is heated and softened by the decorative sheet and the injection molding simultaneous decoration method in the form of preforming with an injection mold, the adhesive layer is The uncoated surface side was inserted between the male and female molds so as to face the cavity forming surface side of the injection mold, and preliminarily molded and adhered to the surface of the injection molded product simultaneously with the injection molding. Preliminary molding of the decorative sheet was performed by vacuum forming using a female mold for injection molding, and the condition was that after heating at 150 ° C. for 5 seconds, evacuation was started and vacuum molding was performed into a female cavity shape. Further, ABS resin was used as the injection resin, and molding was performed under molding conditions of a resin temperature of 230 ° C. and a mold temperature of 40 ° C.
[0032]
(Comparative Example 1)
In the examples, the antistatic layer was not formed on the base material sheet, and other than that, the decorative layer and the adhesive layer were formed in the same manner as in the examples to obtain an injection-molded simultaneous decorating sheet. And the molded product was obtained with the injection molding simultaneous decorating method of the same conditions as an Example.
[0033]
(Comparative Example 2)
In the examples, the decorative layer and the adhesive layer were formed in the same manner as in the examples except that the amount of the thermally crosslinkable monomer used in the antistatic layer was changed from 25 parts by weight to 100 parts by weight. A decorative sheet was obtained. And the molded product was obtained with the injection molding simultaneous decorating method of the same conditions as an Example.
[0034]
Table 1 shows the performance evaluation results of the decorative resin molded products obtained in the above Examples and Comparative Examples. Each evaluation item was evaluated as follows.
(1) Formability: Visually observe the pre-molded decorative sheet to see if the injection-molded decorative sheet can be stretched to follow the surface shape of the molded product during pre-molding and whether or not the decorative layer has cracked. And evaluated.
(2) Dust adhesion: The amount of dust adhering to the surface of the molded product, which was integrated with the injection-molded decorative sheet and decorated on the surface for one month, was visually determined.
(3) Ash adhesion: A molded product with a decorative surface that is integrated with the injection-molded decorative sheet is exposed to cigarette ash on the molded product surface in an environment of room temperature (22 ° C) and humidity of 40% RH. After the application, the molded product was turned upside down, and the amount of ash remaining on the surface of the molded product was visually determined.
[0035]
[Table 1]

[0036]
As shown in Table 1, in the examples, there was no cracking of the decorative layer during preforming, the moldability was good, and no adhesion of dust or ash was observed. However, in Comparative Example 1, the moldability was good, but because there was no antistatic layer, dust and ash adhered, and the appearance of the molded product was significantly inferior to the Examples. In Comparative Example 2, there is no adhesion of dust and ash, but since the blending ratio of the thermally crosslinkable monomer in the antistatic layer is large, the antistatic layer has poor stretchability and is a decorative layer adjacent to the antistatic layer. Cracks occurred.
[0037]
【The invention's effect】
According to the injection molding simultaneous decorating sheet of the present invention, there is no need for a separate process such as post-coating, and at the same time as molding the molded product, the decorative sheet is laminated and integrated along the uneven shape of the molded product surface. It is possible to perform both surface decoration and antistatic treatment of a three-dimensional molded product at the same time. Moreover, in the form of providing an antistatic layer on the back side of the base sheet, the antistatic layer is not exposed on the surface of the decorative molded product, and the surface becomes a base sheet, so that water resistance and chemical resistance are reduced. Antistatic performance can be imparted without causing In addition, the antistatic layer is A thermally crosslinkable monomer composed of an epoxy compound is blended at a ratio of 10 to 50 parts by weight with respect to 100 parts by weight of an ion conductive amine-modified acrylic resin By using a crosslinked cured product obtained by crosslinking and curing an ion conductive amine-modified acrylic resin with a thermally crosslinkable monomer composed of an epoxy compound, the water resistance and the like of the antistatic layer can be improved. And according to the injection-molding simultaneous decorating method of this invention, the surface-decorated and antistatic molded article can be manufactured efficiently.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing one embodiment of an injection-molded simultaneous decorating sheet of the present invention.
FIG. 2 is a cross-sectional view showing an example of a molded product obtained by the simultaneous injection molding method of the present invention.
FIG. 3 is a conceptual explanatory diagram of an embodiment of the simultaneous injection molding method of the present invention: a state in which a decorative sheet is supplied between molds.
FIG. 4 is the same state as injecting resin after clamping.
[Explanation of symbols]
1 Base sheet
2 Antistatic layer
3 decoration layers (pattern ink layer, metal thin film layer, etc.)
4 Adhesive layer
11 Die plate (movable panel)
12 Die plate (fixed platen)
13 Female
14 Male
15 Injection nozzle
16 Sheet clamp
17 Hydraulic cylinder
18 piston (ram)
M molded product
P resin
S Injection molding simultaneous decoration sheet
W Decorative molded product

Claims

A decorative sheet formed by applying a decorative layer to a base material sheet made of a thermoplastic resin is arranged between a female mold and a male mold, and then the resin in a fluid state is injected into the cavity to thereby decorate the decorative sheet. In the injection molding simultaneous decorative sheet integrated with the molded product,
On at least one surface of both surfaces of the base sheet, and the ion conductive amine-modified acrylic resin, Ri name from crosslinked cured product of thermally crosslinkable monomer consisting of epoxy compounds, thermally crosslinkable monomer consisting of an epoxy compound However, the injection molding simultaneous decorating sheet | seat in which the antistatic layer which is 10-50 weight part is provided with respect to 100 weight part of ion conductive amine modified acrylic resin .

The injection-molded simultaneous decorating sheet according to claim 1 is disposed between a female mold and a male mold, and then the resin in a fluid state is injected into the cavity, thereby integrating the decorating sheet with the molded product. Injection molding simultaneous decoration method.