JPH03150126A - Vacuum and pressure forming machine - Google Patents

Abstract

PURPOSE:To eliminate the development of wrinkles in formed item and improve the formability and adherence of the formed item by a method wherein sheet holders, which locally come into contact with a decorative sheet, are provided in a lower chamber just beneath the decorative sheet in a vacuum and pressure forming machine. CONSTITUTION:Epoxy resin jigs 9 are placed on a table 4 in a lower chamber 3. Further, formed items 8 are placed on the jigs 9. Furthermore, a decorative sheet 5, which is made of polypropylene, for example, and the surface applied with adhesive of which faces toward the formed items, is fixed above sheet supports 7 by being pinched with the peripheral edge parts of an upper and the lower chambers. The interiors of the upper and the lower chambers divided by the decorative sheet are evacuated to the same vacuum. At the same time, the decorative sheet 5 is softened by being heated with a heater 6 provided at the top face of the upper chamber 2. When vacuum reaches 5 Torr, a valve 10a in the upper chamber 2 is opened so as to send compressed air, the difference of the pressure of which from the vacuum of 5 Torr in 3 kg/cm<2>, in the uper chamber, resulting in bonding the decorative sheet onto the surface of the formed item. The resultant decorated formed item has no wrinkle, since no drawdown occurs, resulting in stably obtaining formed item having favorable external appearance.

Description

【発明の詳細な説明】[Detailed description of the invention]

〔産業上の利用分野〕 本発明は、直接印刷により絵付けが不可能な３次元曲面
を有する成形品の絵付けを可能にする真空圧空成形機に
関するものである。 〔従来の技術〕 ３次元一面を有する成形品に化粧シートをラミネートす
るか、あるいは絵柄を転写する絵付は方法の一つとして
、従来より真空圧空成形機を用いたものが知られている
。 これは、下チャンバー内のテーブル上の治具にＩｌ！置
した成形品に対し、成形品の絵付は面に接着剤を塗布し
た化粧シートを接着剤面を向けて上下チャンバーを二分
割するようにチャンバーの周縁に固定し、化粧シートを
ヒーターにより加熱軟化し更に接着剤を活性化すると同
時に、上下チャンバー内を同一真空に減圧した後、上チ
＋ンバー内を圧空状１ｉ（常圧も含む）にしてシートを
成形品の絵付は面に密着することにより絵付けするもの
であった。 〔解決しようとする課題〕 しかし、使用する化粧シートは主に熱可塑性のプラスチ
ックに接着剤を塗布した物であるが、シートを軟化およ
び接着剤を活性化するために行う加熱の際に、急激に垂
れ下がるドローダウン現象が発生する（第４図参照）、
この状態でテーブルを上昇させ、圧空を導入すると成形
品の絵付は面に部分的に皺が発生する。 これを防ぐために、減圧時に上チャンバーの真空度を下
チャンバーの真空度より上げ、気圧差によりドローダウ
ンを防止する方法も考えられるが、微妙な真空度の調整
は困難であり現実的ではない。 また、耐熱性の高いシートを使うと、シートのコストが
高かったり、成形性が悪いという問題があり、安定した
絵付けができなかった。そのため、耐熱性の低い化粧シ
ートでも皺ができず、きれいな絵付けができる真空圧空
成形機の開発が望まれていた。[Industrial Field of Application] The present invention relates to a vacuum-pressure forming machine that makes it possible to decorate molded products with three-dimensional curved surfaces that cannot be decorated by direct printing. [Prior Art] As one of the methods for laminating a decorative sheet or transferring a pattern onto a molded product having a three-dimensional surface, a method using a vacuum-pressure forming machine has been known. This is placed on the jig on the table in the lower chamber! To decorate the molded product, attach a decorative sheet coated with adhesive to the periphery of the chamber with the adhesive side facing up, dividing the upper and lower chambers into two, and soften the decorative sheet by heating with a heater. Furthermore, at the same time as activating the adhesive, reduce the pressure in the upper and lower chambers to the same vacuum, and then set the upper chamber to a pressurized state 1i (including normal pressure) so that the sheet adheres to the surface of the molded product. It was to be painted by [Problem to be solved] However, the decorative sheets used are mainly thermoplastics coated with adhesive, but when heated to soften the sheet and activate the adhesive, A drawdown phenomenon occurs (see Figure 4).
When the table is raised in this state and compressed air is introduced, wrinkles will appear on the surface of the molded product. In order to prevent this, it is possible to raise the degree of vacuum in the upper chamber higher than the degree of vacuum in the lower chamber during depressurization to prevent drawdown due to the pressure difference, but delicate adjustment of the degree of vacuum is difficult and impractical. Furthermore, if a highly heat-resistant sheet is used, there are problems with the high cost of the sheet and poor moldability, making stable painting impossible. For this reason, there was a desire to develop a vacuum-pressure forming machine that would allow decorative sheets with low heat resistance to be painted neatly without wrinkles.

【課題を解決するための手段】[Means to solve the problem]

本発明は、真空圧空成形機中の化粧シート直下の下チ中
ンバー内に、部分的にシートに接するシート保持具を設
けることにより、上記！ＩＩＩを解決した。The present invention achieves the above-mentioned advantages by providing a sheet holder partially in contact with the sheet in the lower chamber directly below the decorative sheet in the vacuum-pressure forming machine. Solved III.

【作用】[Effect]

耐熱性のないシートを加熱しても、ドローダウンが下の
治具によりほぼ抑えられるので成形時に皺が出来ること
がない、また化粧シートてば過剰の加熱が可能なので一
段と成形性と密着性が向上する。 〔実施例〕 第１図のように、真空圧空成形機ｌの下チャンバーの最
上部に、第３図のようなシート保持具７を固定した。シ
ート保持具７は、線状の治具は針金や細い金属の棒が望
ましく、出来ればチャンバーの外壁と同サイズの枠に治
具を取り付け、枠ごとチャンバーの外壁にセットし場合
によって取り外しが自由に出来るものが良い、本実施例
では１度に３個の成形品に絵付けをするために、枠を針
金で３分割した物を使用した。 次に下チャンバー３のテーブル４の上にエポキシ樹脂製
の治具９を載せ、更に成形品８を治具上に１１置した。 次にポリプロピレン製の化粧シート５の接着剤塗布面を
成形品の方に向けて、シート保持具７上方の上下チ中ン
バーの周縁部に挟みこんで固定した。 次に化粧シートにより分割された、上下チャンバーの内
部を同一真空に減圧しながら同時に上チャンバー２天面
のヒータ６により化粧シートを加熱軟化させた。 続いて第２図のように、真空度が５トールに達したとこ
ろで、上チャンバーｌ内の弁１０ａを開放し、差圧にし
て３ｋｇ／ｃｍ”の圧縮した空気をチャンバー内に送り
込み化粧シートを成形品の表面に接着させた。 絵付けされた成形品は、ドローダウンが起こらなかった
ため皺がなく、良好な外観を持つ成形品が安定して得ら
れた。Even if a non-heat resistant sheet is heated, the drawdown is almost suppressed by the jig below, so wrinkles do not form during molding.Furthermore, decorative sheets allow for excessive heating, which further improves moldability and adhesion. improves. [Example] As shown in FIG. 1, a sheet holder 7 as shown in FIG. 3 was fixed to the top of the lower chamber of a vacuum-pressure forming machine 1. The sheet holder 7 is preferably a linear jig made of wire or a thin metal rod.If possible, the jig should be attached to a frame of the same size as the outer wall of the chamber, and the whole frame should be set on the outer wall of the chamber and can be removed as necessary. In this example, in order to paint three molded products at once, a frame divided into three parts with wire was used. Next, a jig 9 made of epoxy resin was placed on the table 4 of the lower chamber 3, and the molded product 8 was placed 11 on the jig. Next, the decorative sheet 5 made of polypropylene was fixed by being sandwiched between the peripheral edges of the upper and lower chambers above the sheet holder 7, with the adhesive-applied surface facing the molded product. Next, while the interiors of the upper and lower chambers divided by the decorative sheet were reduced to the same vacuum, the decorative sheet was simultaneously heated and softened by the heater 6 on the top of the upper chamber 2. Next, as shown in Figure 2, when the degree of vacuum reaches 5 Torr, the valve 10a in the upper chamber 1 is opened, and compressed air with a differential pressure of 3 kg/cm'' is sent into the chamber to form a decorative sheet. It was adhered to the surface of the molded product.The painted molded product did not have wrinkles because drawdown did not occur, and a molded product with a good appearance was stably obtained.

【発明の効果】【Effect of the invention】

シート保持具により、ドローダウンが防げるため、皺が
なく、良好な外観を持つ成形品が安定して得られる。ま
た、ドローダウンが起こり易い化粧シートも使用てきる
ため、材質の選択範囲が広くなりコストダウンが可能と
なる。さらに、加熱温度を上げることが可能なので、成
形性の向上で絵付は範囲が広がる。Since the sheet holder prevents drawdown, a molded product with no wrinkles and a good appearance can be stably obtained. Furthermore, since decorative sheets that are prone to drawdown can also be used, the selection range of materials is widened and costs can be reduced. Furthermore, since it is possible to raise the heating temperature, the range of decoration is expanded by improving moldability.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図ば、本発明の真空圧空成形機の減圧、加熱中の状
態を示す断面図、第２図は、本発明の真空圧空成形機の
絵付は完了後を示す断面図である。 第３図は、本発明のシート保持具一例を示す説明図であ
る。第４図は、従来の真空圧空成形機の減圧、加熱中の
状態を示す断面図である。 ｌ・・・真空圧空成形機 ２・・・￥チャンバー −３−・・下チャンバー ４・・・テーブル ５・・・化粧シート ６・・・ヒータ ７・・・シート保持具 ８・・・成形品 ９・・・治具 １０ａ、１０ｂ−・弁FIG. 1 is a cross-sectional view showing the vacuum-pressure forming machine of the present invention during depressurization and heating, and FIG. 2 is a cross-sectional view showing the vacuum-pressure forming machine of the present invention after painting is completed. FIG. 3 is an explanatory diagram showing an example of the sheet holder of the present invention. FIG. 4 is a sectional view showing a conventional vacuum-pressure forming machine during depressurization and heating. l...Vacuum and pressure forming machine 2...\Chamber-3-...Lower chamber 4...Table 5...Decorative sheet 6...Heater 7...Sheet holder 8...Molded product 9...Jigs 10a, 10b--Valve

Claims (1)

【特許請求の範囲】[Claims] （１）成形品をテーブル上の治具に載置後、化粧シート
でチャンバーを上下に二分割し、前記化粧シートを加熱
軟化させながら、上下二つのチャンバー内を同一真空度
に減圧した後、上チャンバー内の真空系を開放し常気圧
もしくは常気圧より高い圧力の空気を送り込み、化粧シ
ートを成形品の表面に密着させる真空圧空成形機におい
て、化粧シート直下の下チャンバー内に、部分的にシー
トに接するシート保持具を設けてなる真空圧空成形機。(1) After placing the molded product on a jig on the table, divide the chamber into upper and lower halves with a decorative sheet, and while heating and softening the decorative sheet, reduce the pressure in the upper and lower chambers to the same degree of vacuum, and then In a vacuum-pressure forming machine that opens the vacuum system in the upper chamber and sends air at normal pressure or higher pressure to bring the decorative sheet into close contact with the surface of the molded product, a portion of the air is placed in the lower chamber directly below the decorative sheet. A vacuum-pressure forming machine equipped with a sheet holder that comes into contact with the sheet.