JP3732303B2 - Picture sheet for simultaneous injection molding - Google Patents

Description

【００１１】
具体的には、例えば、装飾層に塩化ビニル−酢酸ビニル共重合体を用い、その装飾層に接着剤層が隣接して設けられている場合は、接着剤層中の樹脂に、マレイン酸をモノマー成分として有する樹脂を使用しない。例えば、接着剤をアクリル樹脂から構成する場合、そのアクリル樹脂の共重合モノマーとしてマレイン酸を使用しない。マレイン酸は接着性を向上するモノマー成分であるが、接着性向上の為には他のモノマー成分を使用する等、マレイン酸を使用しない策をとると良い。或いはマレイン酸をモノマー成分として使用しないで済む樹脂系を使用する等の策をとると良い。
【００１２】
また、マレイン酸は、装飾層中の塩化ビニル−酢酸ビニル共重合体自体の共重合モノマーとしても使用しない。すなわち、塩化ビニル−酢酸ビニル−マレイン酸共重合体は使用しない。通常、マレイン酸は接着性向上成分として例えば１０重量％以下で、第３成分として使用されたりする。したがって、装飾層用のインキのバインダーの樹脂や接着剤の樹脂として、従来一般に、塩化ビニル−酢酸ビニル共重合体を使用するという事は、少なくともその主成分と第２成分のモノマーに、塩化ビニルと酢酸ビニルとを使用した樹脂（塩化ビニル−酢酸ビニル共重合体系樹脂とでも言える）を使用するという事であり、実用上はその第３成分として、マレイン酸が使用される場合が多い。すなわち、単に使用樹脂が塩化ビニル−酢酸ビニル共重合体と言った場合、学術的にはそれは純粋な２元共重合体であるが、それを使用する実用上の分野においては、明示が無くても、その樹脂の物性調整の為の共重合モノマーとして、マレイン酸を含有している樹脂の事も大いにあり得るからである。
【００１３】
塩化ビニル−酢酸ビニル共重合体を含有する層に隣接しない層の場合は、その層中の樹脂がマレイン酸をモノマー成分として含有していても、直接に作用することは無い。この点で、該絵付シートの前記塩化ビニル−酢酸ビニル共重合体を含有する層自体、及び少なくとも該層に隣接する層中には、マレイン酸をモノマー成分として有する樹脂を含有しない事が好ましい。しかし、絵付シートを溶断する際はその厚み方向の全層が溶融により混ざり合う為、隣接しない層もマレイン酸を含有しない事がより好ましい。
【００１４】
塩化ビニル−酢酸ビニル共重合体を有する絵付シートにおいて、マレイン酸をモノマー成分として含有しない樹脂を用いると、絵付シート溶断時の周囲の腐食に効果がある理由は定かではないが、樹脂中のマレイン酸のモノマーユニットや、未反応物がある場合は遊離のマレイン酸が、塩化ビニル−酢酸ビニル共重合体の塩化ビニルのモノマーユニットの脱塩酸反応を促進する為と推定される。旧来から、塩化ビニル樹脂に対しては各種の安定剤が知られており、それらは脱塩酸反応を抑制する為の物等である。そして、塩化ビニル−酢酸ビニル共重合体は塩化ビニルの単独重合体である塩化ビニル樹脂よりも、数倍も脱塩酸反応が進みやすい点も、当該共重合体を用い場合に金型等の腐食の問題が顕在化する理由と思われる。
【００１５】
上述の様な特徴を有する本発明の射出成形同時絵付け用の絵付シートの各層は、上述の点以外は、従来公知の絵付シートに用いられている各種材料を使用することができる。
【００１６】
例えば、基材としては、絵付シートを予備成形や樹脂成形中に成形して成形品形状に追従させる必要があれば、延伸性のものを用いる。もちろん、絵付シートの延伸性が必要なけば、非延伸性の紙や金属シート等でも良い。延伸性の基材としては、例えば、延伸性の樹脂フィルムを用いる。例えば、２軸延伸ポリエチレンテレフタレートフィルムでも、形状次第で加熱加圧条件により充分な延伸性を得られるが、低温低圧で延伸性が発現し易いもの例えば、ポリブチレンテレフタレート、又はテレフタレートイソフタレート共重合体等の熱可塑性共重合体ポリエステル系樹脂、ポリプロピレン、ポリエチレン、ポリメチルペンテン、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系樹脂、塩化ビニル樹脂、ナイロン等の低延伸又は無延伸のフィルム等が好ましい。なお、シート成形性が不要ならば、強延伸のフィルムでも使用できる。
また、ポリ塩化ビニリデン、酢酸ビニル−塩化ビニル共重合体（勿論、この場合は前記の如くマレイン酸モノマーについての制約を受ける）、ポリビニルブチラール等のビニル重合体、ポリスチレン、アクリロニトリル−スチレン共重合体、ＡＢＳ（アクリロニトリル−ブタジエン−スチレン共重合体）樹脂等のスチレン系樹脂、酢酸セルロース、ニトロセルロース等のセルロース系樹脂、ポリフッ化ビニリデン、ポリフッ化ビニル等のフッ素樹脂、ポリカーボネート、アクリル系樹脂、ウレタン系熱可塑性エラストマー等のフィルムも用いることができる。また、転写シートの場合は常温でも延伸するゴム膜も使用できる。
基材は、これらフィルムの単層或いは２層以上の積層体として用いる。基材の厚みは材料、用途にもよるが、通常２０〜３００μｍ程度である。シート成形適性なとの点から５０〜１００μｍが好ましい。薄過ぎると絵付シートが伸ばされた場合に破れや皺等を生じ易く、厚過ぎると絵付シートの成形性が低下する。
【００１７】
ラミネートシートの形態において、基材自体を装飾層とする場合は、基材の樹脂中に顔料等の着色剤を練り込んで装飾して、基材を着色透明又は着色不透明、或いは無色不透明又は着色不透明等とする。顔料は後述の装飾層同様に公知の物が使用される。
【００１８】
また、転写シートの形態では、基材には必要に応じ、その転写層側に装飾層等の転写層との剥離性を向上させる為、離型層を設ける。離型層は基材を剥離時に基材と共に転写層から剥離除去される。離型層には、例えば、シリコーン樹脂、メラミン樹脂、ポリアミド樹脂、ウレタン樹脂、ポリオレフィン樹脂、ワックス等を単体で、或いは２種以上混合して用いる。
【００１９】
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層、アルミニウム、クロム等の金属を公知の蒸着法等で部分又は全面に形成した金属薄膜層等である。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、布目模様、文字、幾何学模様、全面ベタなど任意である。絵柄層用インキは、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、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、アクリル系等の電離放射線硬化性樹脂等を、これら樹脂の単体、又は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。
【００２０】
なお、転写シートの形態では、装飾層と共に転写され、装飾層表面を被覆する透明又は半透明の剥離層を、基材乃至は離型層と装飾層との間の剥離性調整、装飾層の表面保護等の為に、これら層間に設けることもある。剥離層のバインダーも絵柄層インキのバインダーと同様の物を用いることができる。なお、剥離層の厚みは０．５〜３０μｍ、通常は２〜１０μｍ程度である。
【００２１】
また、剥離層には、耐候性（耐光性）をより向上させる為に、紫外線吸収剤、光安定剤のどちらか一方、又は両方を添加することができ、その添加量は紫外線吸収剤、光安定剤とも通常０．５〜１０重量％程度であるが、一般的には紫外線吸収剤と光安定剤とを併用するのが好ましい。これより少ないと、耐候性向上効果が充分に得られず、又これより多いと着色化し、多量に入れても効果的に変化がなく好ましくない。
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、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を用いることができる。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。
【００２２】
また、絵付シートの裏面には、成形品となる樹脂との接着性向上のため、シート面にコロナ放電処理、公知の各種プライマー塗工等の易接着処理や感熱型等のの接着剤層の形成を、成形樹脂に応じて適宜行っても良い。
接着剤層は、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、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−メチルスレチ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系樹脂、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、塩素化オレフィン樹脂、ブロックイソシアネートを架橋剤とする２液硬化型ポリウレタン等のポリウレタン樹脂、エポキシ樹脂、フェノール樹脂等の、ポリエステル樹脂、天然又は合成樹脂、各種アイオノマー等の１種又は２種以上を含む混合物等からなる塗液で塗布形成する。
【００２３】
以上の様な構成からなる、本発明の射出成形同時絵付け用の絵付シートを用いることによって、射出成形機に取り付けた射出成形同時絵付け装置において、絵付シートを１ショット毎に溶断を繰り返しても、溶断する周囲に位置する金型や金型キャビティ面、絵付け装置の構成部品等の腐食が発生しない様になる。
【００２４】
そして、本発明の射出成形同時絵付け用の絵付シートを使用して射出成形する樹脂材料は、特に限定されず、従来公知の各種樹脂を使用できる。例えば、熱可塑性樹脂であれば、ポリエチレン、ポリプロピレン等のポリオレフィン樹脂、塩化ビニル樹脂、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）樹脂、ポリカーボネート樹脂、スチレン樹脂、ＡＳ（アクリロニトリル−スチレン共重合体）樹脂等があり、硬化性樹脂であれば、不飽和ポリエステル樹脂、硬化性アクリル樹脂、２液硬化型ウレタン樹脂、エポキシ樹脂等がある。
【００２５】
次に、本発明の絵付シートを用いる射出成形同時絵付け方法の一例として、射出成形型で絵付シートの予備成形も行う例を、図３〜図５を用いて説明しておく。
【００２６】
先ず、最初は、ロールから巻きだされた帯状の絵付シートＳの先端を、チャック３で表裏から把持して、絵付シートを型間に供給して図３又は図４のシート切断前の状態にする。すなわち、チャック３が絵付シートＳを把持したまま下方に移動して、型外部下方に位置するチャック４が絵付シートの先端を把持できる位置まで、絵付シートを搬送する。チャック４が絵付シート先端の把持を完了すると、チャック３は絵付シートの把持を解除して、型外部上方に移動して元の位置まで戻り、次のショットの準備として絵付シートを把持する。次いで、型間に常時位置するクランプ５が、型１側に前進移動（図面左側方向）して、絵付シートを型１のパーティング面に押圧して、固定して、絵付シートの型間への供給が完了する。なお、クランプ５は、例えば型１のキャビティの周囲を囲繞して絵付シートを押圧する様に四角形の枠形状をしている。そして、熱盤１０が、型外部の退避位置から型間に移動し、加熱する絵付シートに対向する位置まで移動する。この状態が図３又は図４である。
【００２７】
そして、次は図５の如く、絵付シートＳの切断と加熱軟化である。熱盤１０が前進し（図面左側方向）、クランプ５に当接する位置まで移動する。そして、絵付シートに対して熱盤の加熱面は所定の距離隔てて加熱し、また、熱盤に設けられた加熱線条２０も絵付シートに接触して、絵付シートを溶かして切断する。この際、腐食性のガスは発生しない。なお、型１のパーティング面には加熱線条の切断作用を邪魔しない様に受け溝６を切断手段２０と対向する面部分に設けてある。図５はまさにこれらか絵付シートが切断される直前の状態である。
【００２８】
そして、絵付シートの加熱軟化後、またはそれと同時に、型１に設けた通気孔（図示せず）から吸気して、絵付シートを成形して型１のキャビティ面に密着させる。成形後に、熱盤１０は両型間から型外部の退避位置に移動・退避させる。その後、両型１、２を型締めする。型２のパーティング面には、クランプ５が型締めを邪魔しない様にクランプを収納できる凹部となる受け溝７をクランプと対向する面部分に設けてある。
そして、両型で形成されるキャビティに樹脂を射出し、型開きすれば、成形と同時に絵付シートにより表面が絵付けされた成形品が得られる。
【００２９】
なお、本発明でいう「絵付け」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。
なお、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「熱溶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」を射出する事も包含する。
【００３０】
【発明の効果】
本発明によれば、帯状として用意する絵付シートを、長手方向に１ショット分の長さに溶断により切断する際に、絵付シートが塩化ビニル−酢酸ビニル共重合体を含有していても、切断時に周囲に有る金型、射出成形同時絵付け装置や射出成形機の部品等を腐食しない。
特に、金型のうちでも成形品表面品質に影響するキャビティ面により接近した位置で、絵付シートの無駄を少なくして溶断する場合でも、キャビティ面を腐食させずに絵付シートを切断できる。
【図面の簡単な説明】
【図１】本発明の射出成形同時絵付け用の絵付シートの一形態の断面図。
【図２】本発明の射出成形同時絵付け用の絵付シートの他の形態の一例の断面図。
【図３】絵付シートを加熱線条で溶断する一例の概念的説明図（シート切断前）。
【図４】絵付シートを加熱線条で溶断する他の例の概念的説明図（シート切断前）。
【図５】図４において絵付シートが加熱線条で溶断される時の概念的説明図。
【符号の説明】
１ 型（雌型）
２ 型（雄型）
３ チャック（シート把持搬送手段）
４ チャック（シート把持手段）
５ クランプ（シート固定手段）
６ 受け溝
７ 受け溝
１０ 熱盤
２０ 加熱線条
２１ 支持具
２２ 熱盤の絵付シート供給方向上流側の外縁
３１ 基材
３２ 装飾層
３３ 接着剤層
Ｓ 絵付シート[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a picture sheet for simultaneous injection molding.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an injection molding simultaneous painting method in which a pattern or the like is provided on the outer surface simultaneously with molding of a molded product has been performed in various modes.
In Japanese Examined Patent Publication No. 50-19132, after a vacuum-formed sheet made of a thermoplastic resin is formed using a female mold provided with a vacuum forming vent, both the male and female molds are clamped, and the molten resin is molded into both molds. And a method of integrating a picture sheet with an outer surface of a molded product by injecting into a cavity formed by the above method. Thus, the injection molding simultaneous painting method is a method in which vacuum molding and injection molding are combined, and a pattern can be formed on a complicated curved surface shape.
In JP-A-6-315950, a belt-like picture sheet wound from a roll is fed between both male and female molds, and the picture sheet is attached to the female parting surface so that the periphery is fixed by a sheet pressing frame. After supplying the sheet, the hot platen is moved between the molds from the retreat position outside the mold, the picture sheet is heated and softened, the picture sheet is molded with the injection mold, and then along the cavity surface. Is disclosed in which a mold is retracted to a retracted position outside the mold, both molds are clamped, and molten resin is injected into a cavity formed by both molds.
And when using a belt-like picture sheet, the ease of handling after injection molding, and the heat and stress of the pre-molding process and injection molding process are retroactive to the sheet for the next shot upstream (sheet supply side). From the standpoint of prevention, there is a method in which the picture sheet is cut into one shot size before clamping. Also in the above Japanese Patent Laid-Open No. 6-315950, the heating plate is provided with cutting means comprising heating filaments, and after the picture sheet is fixed to the female mold by the sheet pressing frame which is the sheet pressing means, the heating board heats and softens the picture sheet. Thus, a technique for fusing a picture sheet with a heating filament when it approaches the picture sheet is disclosed. Also, in Japanese Patent Publication No. 4-9647, a picture sheet is adsorbed to the heating surface of the hot platen when it is in a retracted position out of the mold, and the picture sheet is cut by a cutting means such as an ultrasonic cutter for one shot. A technique is disclosed in which a picture sheet is held on a heating plate and supplied between the male and female molds by the heating plate.
In addition, as a technique for cutting the picture sheet, a cutting blade and a heating filament are provided on the mold side, or the picture sheet is pressed against the mold with a cutting blade provided on the sheet pressing means, and the cutting blade and the mold There is also a method of cutting a picture sheet by joint work.
Among them, the method of fusing a painted sheet with a heating wire such as a nichrome wire is a preferable form in that the structure can be made simpler and the painting apparatus can be made cheaper than a blade cut by mechanical driving.
[0003]
[Problems to be solved by the invention]
However, it has been found that when a heated sheet is used for cutting a picture sheet and the fusing of the picture sheet (cutting by heat melting) is repeated, the surface of the surrounding mold and the surface of the device parts are corroded. In particular, when the cavity surface of the mold is corroded, it is a serious problem because it directly affects the surface quality of the molded product.
Moreover, this corrosion problem occurred in a sheet with a picture using a vinyl chloride-vinyl acetate copolymer as a resin such as an adhesive layer or a decorative layer. Moreover, since this vinyl chloride-vinyl acetate copolymer has good physical properties such as adhesiveness, various molded resins such as ABS, various sheets with pictures based on ABS, vinyl chloride resin and polypropylene resin, It is an excellent resin frequently used, and it has been desired to solve the problem of corrosion in a sheet with a picture using a vinyl chloride-vinyl acetate copolymer.
[0004]
3 and 4 show an example of an injection molding simultaneous painting apparatus in which the heating wire 20 is provided on the heating plate 10 for cutting the painting sheet S. FIG. In these drawings, the heating wire 20 is attached to the heating platen 10 with a support 21. Further, as shown in the figure, the heating filament is stretched in a direction perpendicular to the feeding direction of the picture sheet at a position advanced from the heating surface of the heating plate toward the front picture sheet. As a result, when the heating plate approaches the picture sheet and moves to the heating position, the heating filament comes into contact with the picture sheet, and the tip of the picture sheet supplied between both molds in the form of a strip is taken for one shot. Cut to size and cut off from the rest. FIG. 3 shows an example in which the heating wire is provided on the upper side of the outer edge 22 on the upper side of the heating plate, that is, on the upstream side in the painting sheet supply direction from the heating plate, and FIG. It is an example provided below the outer edge 22 on the upper side of the board, that is, downstream in the picture sheet supply direction.
In particular, as shown in FIG. 4 rather than FIG. 3, if the heating filament is provided on the downstream side in the painting sheet supply direction (however, upstream from the clamp 5) and the painting sheet is melted, the painting sheet is correspondingly removed. However, as shown in FIG. 5, the cavity surface of the mold was brought closer, and corrosion of the cavity surface was a concern.
[0005]
Therefore, in the present invention, when the above-mentioned problems are solved and the picture sheet is melted to a size for one shot using a heating wire shape and then clamped, vinyl chloride-vinyl acetate is added to the picture sheet. Even if a polymer is used, it is an object of the present invention to provide a picture sheet that does not corrode the mold around the melted part or the parts of the injection molding simultaneous painting apparatus and the injection molding machine.
[0006]
[Means for Solving the Problems]
Therefore, in order to solve the above-described problems, in the present invention, a sheet with a picture is supplied between both molds composed of a pair of molds, both molds are clamped, and a resin is injected into a cavity formed by both molds. Simultaneous injection molding method in which mold-clamping is performed after fusing a strip-shaped picture sheet to the size of one shot when painting the surface of a molded article by transfer or lamination with a picture sheet simultaneously with molding A painting sheet having at least one layer composed of a vinyl chloride-vinyl acetate copolymer used in the above, a layer itself containing the vinyl chloride-vinyl acetate copolymer of the painting sheet, and at least adjacent to the layer The layer including the vinyl chloride-vinyl acetate copolymer in the layer did not contain a resin having maleic acid as a monomer component, and was a painting sheet for simultaneous injection molding. As a result, it is possible to prevent the mold and the device around the part to be melted from being corroded.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a painting sheet for simultaneous injection molding painting of the present invention will be described with reference to the drawings.
[0008]
First, the painting sheet for simultaneous injection molding of the present invention may be in the form of a transfer sheet or a laminate sheet. FIG. 1 is a cross-sectional view showing one embodiment of a picture sheet of the present invention. The picture sheet S in the figure has a configuration in which a decoration layer 32 and an adhesive layer 33 are sequentially laminated on a base material 31. Moreover, FIG. 2 shows an example of another form, and the sheet S with a picture of the figure is the structure which consists of the base material 31 and the decoration layer 32. FIG. As shown in FIG. 2, there is a form in which the adhesive layer is omitted when the picture sheet has adhesiveness even without the adhesive layer. In addition, when a sheet | seat with a picture is a transfer sheet, a peelable base material is used for a base material, and the decoration layer and adhesive layer on a base material become a transfer layer which transfers. Moreover, in the form of a laminate sheet, there is a configuration of only a base material. The base material itself forms a decorative layer by kneading and mixing the pigment into the base material.
As a sheet with a picture, the vinyl chloride-vinyl acetate copolymer itself does not usually constitute a base material, and the vinyl chloride-vinyl acetate copolymer is a binder resin of the decorative layer 32 or a resin of the adhesive layer 33. Used as However, vinyl chloride-vinyl acetate copolymer may be present in other layers. For example, a vinyl chloride-vinyl acetate copolymer is added to the resin of the base material.
The injection molding simultaneous painting method using the painting sheet of the present invention includes any of a method of preforming a painting sheet with an injection mold or other mold, and a method of not performing preforming of a painting sheet. Applicable. Further, the timing of cutting the picture sheet into one shot may be a method of cutting the sheet-like picture sheet into one shot after being supplied between a pair of molds, or cutting the picture sheet into one shot outside the mold. A method of supplying a sheet with a sheet between the molds may be used.
[0009]
In the picture sheet of the present invention, the vinyl chloride-vinyl acetate copolymer-containing layer itself, or at least the layer adjacent to the layer, including the vinyl chloride-vinyl acetate copolymer, maleic acid It is set as the structure which does not contain resin which has as a monomer component. The substrate does not contain any monomer component of vinyl chloride, vinyl acetate, and maleic acid, and as shown in FIG. 1, the constituent monomers of each layer when the substrate has a decorative layer and an adhesive layer as shown in FIG. Table 1 shows the combinations.
[0010]
[Table 1]

[0011]
Specifically, for example, when a vinyl chloride-vinyl acetate copolymer is used for the decoration layer and the adhesive layer is provided adjacent to the decoration layer, maleic acid is added to the resin in the adhesive layer. Do not use a resin as a monomer component. For example, when the adhesive is made of an acrylic resin, maleic acid is not used as a copolymerization monomer for the acrylic resin. Maleic acid is a monomer component that improves adhesiveness, but in order to improve adhesiveness, it is better to take measures not to use maleic acid, such as using other monomer components. Alternatively, it is preferable to take measures such as using a resin system that does not require maleic acid as a monomer component.
[0012]
Further, maleic acid is not used as a copolymerization monomer for the vinyl chloride-vinyl acetate copolymer itself in the decorative layer. That is, a vinyl chloride-vinyl acetate-maleic acid copolymer is not used. Usually, maleic acid is used as a third component, for example, at 10% by weight or less as an adhesion improving component. Therefore, the use of a vinyl chloride-vinyl acetate copolymer as a binder resin or adhesive resin for the decorative layer generally means that at least the main component and the second component monomer are vinyl chloride. And vinyl acetate (also referred to as vinyl chloride-vinyl acetate copolymer resin), and in practice, maleic acid is often used as the third component. That is, when the resin used is simply a vinyl chloride-vinyl acetate copolymer, it is scientifically a pure binary copolymer, but there is no indication in the practical field of using it. This is because a resin containing maleic acid can be greatly used as a copolymerization monomer for adjusting the physical properties of the resin.
[0013]
In the case of a layer not adjacent to the layer containing the vinyl chloride-vinyl acetate copolymer, even if the resin in the layer contains maleic acid as a monomer component, it does not act directly. In this respect, it is preferable that the layer containing the vinyl chloride-vinyl acetate copolymer itself and at least the layer adjacent to the layer do not contain a resin having maleic acid as a monomer component. However, when the picture sheet is melted, all the layers in the thickness direction are mixed by melting, so it is more preferable that the layers not adjacent to each other do not contain maleic acid.
[0014]
If a resin that does not contain maleic acid as a monomer component is used in a paint sheet having a vinyl chloride-vinyl acetate copolymer, the reason why it is effective for surrounding corrosion when the paint sheet is melted is not clear, but the malein in the resin If there is an acid monomer unit or an unreacted substance, it is presumed that free maleic acid accelerates the dehydrochlorination reaction of the vinyl chloride monomer unit of the vinyl chloride-vinyl acetate copolymer. From the past, various stabilizers have been known for vinyl chloride resins, and these are substances for suppressing the dehydrochlorination reaction. The vinyl chloride-vinyl acetate copolymer is more susceptible to dehydrochlorination reaction several times than the vinyl chloride resin, which is a vinyl chloride homopolymer. This seems to be the reason why this problem becomes apparent.
[0015]
For each layer of the painting sheet for simultaneous injection molding of the present invention having the above-described characteristics, various materials used in conventionally known painting sheets can be used except for the above points.
[0016]
For example, as a base material, if it is necessary to form a picture sheet during preforming or resin molding to follow the shape of the molded product, a stretchable material is used. Of course, non-stretchable paper, metal sheets, etc. may be used if the stretchability of the picture sheet is required. For example, a stretchable resin film is used as the stretchable substrate. For example, even with a biaxially stretched polyethylene terephthalate film, sufficient stretchability can be obtained depending on the shape depending on the heating and pressurizing conditions, but the stretchability is easily developed at low temperature and low pressure. For example, polybutylene terephthalate or terephthalate isophthalate copolymer Preferred are thermoplastic copolymer polyester resins such as polyolefin resins such as polypropylene, polyethylene, polymethylpentene, and olefin thermoplastic elastomers, and low-stretched or non-stretched films such as vinyl chloride resin and nylon. If sheet formability is not required, a strongly stretched film can be used.
In addition, polyvinylidene chloride, vinyl acetate-vinyl chloride copolymer (of course, subject to the restrictions on the maleic acid monomer as described above), vinyl polymers such as polyvinyl butyral, polystyrene, acrylonitrile-styrene copolymer, Styrenic resins such as ABS (acrylonitrile-butadiene-styrene copolymer) resin, cellulose resins such as cellulose acetate and nitrocellulose, fluororesins such as polyvinylidene fluoride and polyvinyl fluoride, polycarbonate, acrylic resins, urethane heat A film such as a plastic elastomer can also be used. In the case of a transfer sheet, a rubber film that can be stretched even at room temperature can be used.
The substrate is used as a single layer or a laminate of two or more layers of these films. Although the thickness of a base material is based also on a material and a use, it is about 20-300 micrometers normally. 50-100 micrometers is preferable from the point of sheet forming suitability. If it is too thin, it tends to cause tears, wrinkles and the like when the picture sheet is stretched, and if it is too thick, the formability of the picture sheet decreases.
[0017]
In the form of a laminate sheet, when the base material itself is used as a decoration layer, a colorant such as a pigment is kneaded and decorated in the resin of the base material, and the base material is colored transparent or colored opaque, or colorless opaque or colored. It shall be opaque. As the pigment, a known material is used in the same manner as the decorative layer described later.
[0018]
Moreover, in the form of the transfer sheet, a release layer is provided on the substrate as necessary to improve the peelability from the transfer layer such as a decorative layer on the transfer layer side. The release layer is peeled off from the transfer layer together with the base material when the base material is peeled off. For the release layer, for example, a silicone resin, a melamine resin, a polyamide resin, a urethane resin, a polyolefin resin, a wax, or the like is used alone or in combination of two or more.
[0019]
The decoration layer is a conventionally known method such as gravure printing, silk screen printing or offset printing, a pattern layer printed with a pattern or the like with a material, a metal formed of a metal such as aluminum or chromium on a part or the whole surface by a known vapor deposition method or the like A thin film layer or the like. The pattern is arbitrary, such as a stone pattern such as marble or granite, a tile-like pattern, a brick-like pattern, a cloth-like pattern, a character, a geometric pattern, and a solid pattern. The pattern layer ink is composed of a vehicle composed of a binder, a colorant such as a pigment or a dye, and various additives appropriately added thereto. Binders include acrylic resins, chlorinated polyolefin resins, chlorinated polypropylene, vinyl acetate, vinyl chloride-vinyl acetate copolymers, thermoplastic resins such as cellulose resins, normal temperature or thermosetting such as polyurethane resins and epoxy resins. A resin, an ionizing radiation curable resin such as an acrylic resin, or the like is used in the form of a single substance or a mixture 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.
[0020]
In the form of the transfer sheet, a transparent or translucent release layer that is transferred together with the decorative layer and covers the surface of the decorative layer is used to adjust the peelability between the substrate or the release layer and the decorative layer, It may be provided between these layers for surface protection and the like. As the binder for the release layer, the same binder as that for the pattern layer ink can be used. The release layer has a thickness of 0.5 to 30 μm, usually about 2 to 10 μm.
[0021]
In addition, in order to further improve the weather resistance (light resistance), either or both of an ultraviolet absorber and a light stabilizer can be added to the release layer. The stabilizer is usually about 0.5 to 10% by weight, but it is generally preferable to use an ultraviolet absorber and a light stabilizer in combination. If it is less than this, the weather resistance improving effect cannot be sufficiently obtained, and if it is more than this, it is colored, and even if it is added in a large amount, it is not preferable because it does not change effectively.
In addition to organic ultraviolet absorbers such as benzotriazole-based, benzophenone-based, and salicylic acid-based UV absorbers, inorganic particles such as fine particles of zinc oxide, cerium oxide, and titanium oxide with a particle size of 0.2 μm or less should be used. Can do. As the light stabilizer, a hindered amine radical scavenger such as bis- (2,2,2,6,6-tetramethyl-4-piperidyl) sebacate can be used.
[0022]
Also, on the back side of the picture sheet, in order to improve the adhesion with the resin that will be the molded product, the sheet surface has an adhesive layer such as corona discharge treatment, easy adhesion treatment such as various known primer coatings, and a heat sensitive type adhesive layer. The formation may be appropriately performed according to the molding resin.
For the adhesive layer, 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-methyl seletin, or styrene copolymers, poly (meth) acrylic. Acrylic resins such as methyl acid, poly (meth) acrylate, poly (meth) butyl acrylate, polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, polyvinyl Vinyl polymers such as butyral, rosin, rosin-modified maleic resin, rosin-modified phenolic resin, rosin ester resins such as polymerized rosin, polyisoprene rubber, polyisobutyl rubber, styrene butadiene rubber, butadiene acrylonitrile Rubber resins such as rubber, coumarone resin, vinyl toluene resin, polyamide resin, chlorinated olefin resin, polyurethane resin such as two-component curable polyurethane using blocked isocyanate as a cross-linking agent, polyester resin such as epoxy resin, phenol resin, It is formed by coating with a coating liquid comprising a mixture containing one or more of natural or synthetic resins and various ionomers.
[0023]
In the injection molding simultaneous painting apparatus attached to the injection molding machine by using the painting sheet for injection molding simultaneous painting of the present invention having the above-described configuration, the painting sheet is repeatedly blown for each shot. However, corrosion of the mold, the mold cavity surface, the component parts of the painting apparatus, etc. located around the fusing area will not occur.
[0024]
And the resin material injection-molded using the sheet | seat for injection molding simultaneous painting of this invention is not specifically limited, Conventionally well-known various resin can be used. For example, for thermoplastic resins, polyolefin resins such as polyethylene and polypropylene, vinyl chloride resins, acrylic resins, ABS (acrylonitrile-butadiene-styrene copolymer) resins, polycarbonate resins, styrene resins, AS (acrylonitrile-styrene copolymer) For example, unsaturated polyester resins, curable acrylic resins, two-component curable urethane resins, and epoxy resins can be used.
[0025]
Next, as an example of the injection molding simultaneous painting method using the painting sheet of the present invention, an example in which the painting sheet is preformed with an injection mold will be described with reference to FIGS.
[0026]
First, the front end of the belt-like picture sheet S unwound from the roll is gripped from the front and back by the chuck 3, and the picture sheet is supplied between the molds to the state before cutting the sheet in FIG. 3 or FIG. To do. That is, the chuck 3 moves downward while gripping the picture sheet S, and conveys the picture sheet to a position where the chuck 4 positioned below the outside of the mold can grip the leading edge of the picture sheet. When the chuck 4 completes gripping the leading edge of the picture sheet, the chuck 3 releases the gripping of the picture sheet, moves upward to the outside of the mold, returns to the original position, and grips the picture sheet in preparation for the next shot. Next, the clamp 5 that is always located between the molds moves forward (to the left in the drawing) toward the mold 1 side, presses and fixes the picture sheet against the parting surface of the mold 1, and moves between the molds of the picture sheet. Supply is completed. The clamp 5 has, for example, a square frame shape so as to surround the cavity of the mold 1 and press the picture sheet. Then, the hot platen 10 moves from the retreat position outside the mold to between the molds, and moves to a position facing the picture sheet to be heated. This state is shown in FIG. 3 or FIG.
[0027]
Then, as shown in FIG. 5, the painting sheet S is cut and softened by heating. The hot platen 10 moves forward (to the left in the drawing) and moves to a position where it contacts the clamp 5. Then, the heating surface of the heating plate is heated at a predetermined distance with respect to the painting sheet, and the heating filament 20 provided on the heating plate also contacts the painting sheet to melt and cut the painting sheet. At this time, no corrosive gas is generated. The parting surface of the mold 1 is provided with a receiving groove 6 on a surface portion facing the cutting means 20 so as not to disturb the cutting action of the heating filament. FIG. 5 shows the state immediately before these or the picture sheet is cut.
[0028]
Then, after heat-softening of the picture sheet or simultaneously with it, air is sucked from a vent (not shown) provided in the mold 1 to form the picture sheet and adhere to the cavity surface of the mold 1. After molding, the hot platen 10 is moved / retracted from between both molds to a retreat position outside the mold. Thereafter, both molds 1 and 2 are clamped. The parting surface of the mold 2 is provided with a receiving groove 7 serving as a concave portion in which the clamp 5 can be stored so that the clamp 5 does not interfere with the mold clamping, on a surface portion facing the clamp.
If a resin is injected into the cavity formed by both molds and the mold is opened, a molded product having a surface painted with a picture sheet at the same time as molding can be obtained.
[0029]
In addition, “painting” as used in the present invention means functions other than simply giving a visible pattern such as a pattern, character, figure, etc. to the molded product, a pattern that is not visible, or a hard coating film, conductivity, etc. It also includes providing a sex layer.
The injection molding referred to in the present invention refers to “thermosetting or two-component reaction curable resin in a molten state at room temperature” in addition to injecting “thermomelted thermoplastic resin” that is usually used in general injection molding. Including injection.
[0030]
【The invention's effect】
According to the present invention, when a picture sheet prepared as a strip is cut by fusing to a length of one shot in the longitudinal direction, cutting is performed even if the picture sheet contains a vinyl chloride-vinyl acetate copolymer. Sometimes it does not corrode surrounding molds, injection molding simultaneous painting equipment, injection molding machine parts, etc.
In particular, even when the die surface is cut closer to the cavity surface that affects the surface quality of the molded product, the painted sheet can be cut without corroding the cavity surface even when fusing with less waste of the painted sheet.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of one embodiment of a picture sheet for simultaneous injection molding of the present invention.
FIG. 2 is a cross-sectional view of an example of another embodiment of a painting sheet for simultaneous painting by injection molding according to the present invention.
FIG. 3 is a conceptual explanatory diagram of an example of fusing a picture sheet with a heating filament (before cutting the sheet).
FIG. 4 is a conceptual explanatory diagram of another example in which a picture sheet is fused with a heating filament (before cutting the sheet).
FIG. 5 is a conceptual explanatory diagram when a picture sheet is blown off by a heating filament in FIG. 4;
[Explanation of symbols]
Type 1 (female)
Type 2 (male type)
3 Chuck (sheet gripping and conveying means)
4 Chuck (sheet gripping means)
5 Clamp (sheet fixing means)
6 Receiving groove 7 Receiving groove 10 Heating plate 20 Heating line 21 Supporting tool 22 Outer edge 31 on the upstream side of the heating plate with the painting sheet supplied Base material 32 Decoration layer 33 Adhesive layer S Painting sheet

Claims (1)

A picture sheet is supplied between two molds consisting of a pair of molds, both molds are clamped, a resin is injected into a cavity formed by both molds, and a molded product by transfer or lamination with a picture sheet simultaneously with molding. When painting the surface, it consists of a vinyl chloride-vinyl acetate copolymer used in the injection molding simultaneous painting method in which the band-shaped picture sheet is cut into a size for one shot and then clamped. In a picture sheet having at least one layer,
The layer containing the vinyl chloride-vinyl acetate copolymer itself of the picture sheet, and at least the layer adjacent to the layer, including the vinyl chloride-vinyl acetate copolymer, have maleic acid as a monomer component. A sheet for painting with simultaneous injection molding, which does not contain a resin.

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