JP2005138459A - Heat seal molding method for film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To heighten solicitation force by giving an engraved cubic effect to a film to be heat-sealed. <P>SOLUTION: When a tray 1 is mounted on a lower mold 5, and a thermoplastic film 2 is pressed by an upper mold 6 to be heated and bonded (heat-sealed) to the flange 3 of the tray 1, a molding block 7 having a molding recess 8 is set in the upper mold 6, and the film 2 is sucked and adhered to the molding block 7 while being heated to form a pattern 4 comprising a projection in a prescribed shape on the film 2. Since the engraved pattern 4 having a cubic effect is formed on the film 2 sealing the upper surface of the tray 1, the solicitation force of a package is improved without adding a process other than the heat sealing. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a heat sealing and forming method for a film used for sealing a food container or the like.

  For example, as shown in FIG. 5, in order to seal a paper or plastic tray 50 that contains food or the like, a thermoplastic film 51 is placed on the upper surface of the tray 50, and a film is placed on a flange 52 that surrounds the outer periphery of the tray 50. A heat sealing method is used in which the film 51 and the flange 52 are joined by pressing and heating the 51 with a mold.

  However, as described above, simply heat-sealing the film has a problem that the impression as a package is thin and appealing power is weak.

  Then, this invention makes it a subject to give a stamp-like three-dimensional effect to the film to heat-seal, and to raise appeal power.

  In order to solve the above-described problems, the present invention provides a molding block having irregularities for molding on the mold when the thermoplastic film is heat-sealed by pressing the thermoplastic film with a mold and heating the film on the molding block. However, it was sucked and brought into close contact with each other to form irregularities of a predetermined shape on the film.

  In this way, if the film is sucked and molded while heat-sealing, a three-dimensional engraved pattern can be formed on the film, so that the appeal of the package can be improved. Since the steps other than heat sealing do not increase, the packaging efficiency does not decrease.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  As shown in FIG. 1, a sealed container using the heat seal molding method according to the present invention covers a thermoplastic film 2 on the upper surface of a paper tray 1 for storing food, and the film 2 is placed on the outer periphery of the tray 1. The film 3 is heat-sealed, and a stamped pattern 4 is formed on the film 2.

  When packaging the sealed container, as shown in FIG. 2, the tray 1 is set on the lower mold 5 so that the flange 3 is placed, and the film 2 is inserted between the lower mold 5 and the upper mold 6. The upper die 6 is provided with a molding block 7, a molding recess 8 is formed in the molding block 7, and a suction pump P is connected to the air passage 9 opened by the recess 8.

  Next, as shown in FIG. 3, the upper die 6 is lowered, the film 2 is pressed against the flange 3 by the outer periphery of the upper die 6 heated in advance, and the film 2 is vacuumed as the pump P is driven. Then, the pattern 4 that forms a convex portion along the concave portion 8 is formed by closely contacting the molding block 7 and heating.

  Thereafter, as shown in FIG. 4, when the upper mold 6 is raised, the film 2 is pulled away from the molding block 7 while being bent upward by the suction force from the concave portion 8, and restored along with the increase in the separation distance, Heat sealing and molding of the film 2 are completed.

  Thus, when the film 2 is sucked and molded while heat-sealing, a three-dimensional stamped pattern 4 is formed on the film 2 that seals the upper surface of the tray 1, so that the appeal of the package is improved. In addition, there is no increase in the number of processes other than heat sealing in this processing, so that the packaging efficiency is not lowered.

  Incidentally, as the film 2, a stretched polypropylene film having a thickness of about 25 μm is generally used, but a thin paper coated with a thermoplastic resin or a non-woven fabric may be used.

  The negative pressure generated in the recess 8 by the pump P is preferably about −20 mmHg, and the temperatures of the outer peripheral portion of the upper mold 6 and the molding block 7 are preferably about 130 ° C.

  In addition, if the depth of the concave portion 8 is about 1 mm as in the above embodiment, the width of the concave portion 8 is preferably about 1 mm to 2 mm, but these values are based on the design of the design and the material of the film 2. May be set as appropriate.

  In the above embodiment, the concave portion 8 is formed in the molding block 7 and the pattern 4 is formed on the film 2. However, the convex portion is formed on the molding block 7 and the concave portion is formed on the film 2. You may make it form a pattern.

The perspective view of the sealing container which concerns on embodiment of this invention Sectional view showing the process before heat sealing and molding Sectional view showing the state of heat sealing and molding as above Sectional view showing the process after heat sealing and molding Perspective view of a sealed container by conventional heat sealing

Explanation of symbols

1 Tray 2 Film 3 Flange 4 Design 5 Lower mold 6 Upper mold 7 Molding block 8 Recess 9 Air passage P Pump

Claims (1)

  At the time of heat sealing, in which a thermoplastic film is pressed by a mold and heat-bonded, a molding block having irregularities for molding is provided on the mold, and the film is sucked and adhered to the molding block while being heated. A heat seal molding method for a film, characterized by forming irregularities in shape.

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