JPH1110810A - Cover material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a cover material hardly curled and to make it have shape retaining properties, by laminating a heat-resistant film on both sides of a base of a co-extruded film formed by providing coat layers of high-density polypropylene on both sides of a central layer constituted of high-density polyethylene and a polypropylene polymer, and by providing a sealant later on the bottom face of the heat-resistant film. SOLUTION: A base layer 4 formed of a co-extruded film of a central layer 1, prepared by compounding high-density polyethylene with a polypropylene polymer and coat layers 2 constituted of the high-density polyethylene, and provided on both sides of the central layer 1, is used, and heat-resistant films 6 constituted of polyethylene terephthalate are laminated on both sides of the base layer 4, by a dry laminate method by using a two-part urethane adhesive. On the lower side of a laminated base thus obtained, a sealant layer 8 constituted of a low-density polyethylene film is laminated by the same adhesive and the laminate method, thereby obtaining a laminated material. A cover material in the shape of a sheet is prepared by punching this laminated material in a circle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lid suitable for sealing a molded container having an opening at the center and a flange at the periphery.

[0002]

2. Description of the Related Art As a lid material for sealing a molded container having an opening at the center and a flange at the periphery, a lid material having a laminated structure using aluminum foil, a lid material having a laminated structure using a paper layer, and a plastic material There is a lid material having a laminated structure composed of:

[0003] Among them, a lid material having a laminated structure using aluminum foil has a certain rigidity, is hard to curl, and has a shape retaining property. However, it is widely used because it can be applied to a continuous type in which a roll-shaped film is supplied. In addition, the lid member using the aluminum foil has excellent physical properties such as light-shielding properties and moisture-proofing properties. As described above, although the lid material is excellent in function, there is a problem that it is impossible to use a metal detector for inspecting whether a foreign matter such as a metal piece of a container is mixed.

Therefore, a lid material made of a laminated material using a paper layer or a lid material laminated with a plastic material has been proposed.

However, the lid material is susceptible to the external environment. In particular, under the condition of high humidity, the sheet layer supplies a lid material punched into a predetermined shape because of curling due to moisture absorption of the paper layer. When sealing is performed according to the formula, there is a problem that the seal is shifted. In addition, bubbling may occur due to expansion of air in the paper layer and evaporation of water during sealing.

[0006]

SUMMARY OF THE INVENTION Accordingly, the present invention relates to a cover having the same performance (curlability, punching suitability, etc.) as a stamped type label, even if it is made of plastic, as a label using an aluminum foil. The purpose is to provide materials.

[0007]

SUMMARY OF THE INVENTION The present invention is directed to a co-extruded film in which a coating layer made of high-density polyethylene is provided on both sides of a central layer made of high-density polyethylene and a polypropylene-based polymer. A lid material obtained by punching a laminated material in which a sealant layer is provided on a lower surface of a laminated base material on which a film is laminated, into a predetermined shape.

[0008] A second invention is a lid material wherein the central layer of the base material is constituted by blending a high-density polyethylene and a polypropylene-based polymer with an inorganic filler. According to a third aspect of the present invention, the ratio of the thickness of the center layer to the thickness of the coating layer of the base material is 6 to 8/2.
-1. A fourth invention is a lid member wherein the heat-resistant film is a polyethylene terephthalate film.

A fifth invention is a lid material obtained by laminating the heat-resistant film on a substrate by either a dry lamination method or a non-sol lamination method.

[0010] The cover material of the present invention is provided with a coating layer made of the same resin as the center layer so that the base material has a certain rigidity, and furthermore, a heat-resistant film is laminated on both sides. Even if the material is punched, it can be kept flat,
It can be supplied in a single-wafer manner and the opening of the container can be sealed. Further, since the base material has a configuration in which the coating layers are provided on both sides of the center layer, the heat-resistant film can be laminated by a dry lamination method or a non-sol lamination method.

[0011]

FIG. 1 is a cross-sectional view showing an example of a cover material according to the present invention. A cover layer 2 made of high-density polyethylene is provided on both sides of a center layer 1 in which a polypropylene polymer is mixed with high-density polyethylene. 2, a base material 4 made of a co-extruded film, and a sealant layer 8 provided on the lower surface of a laminated film 7 in which heat resistant films 6, 6 are bonded to both sides of the base material 4 with adhesive layers 5, 5 therebetween. It is a lid material.

Here, the center layer 1 is formed not only by blending a polypropylene polymer with high-density polyethylene,
Further, by adding an inorganic filler such as talc, coloring and rigidity can be imparted. Further, the ratio of the thickness of the center layer 1 to the thickness of the coating layer is suitably in the range of 6 to 8/2 to 1, and the thickness of the substrate 4 is suitably in the range of 80 to 110 μm.

Next, the heat-resistant film 6 can be used as long as it is a stretched plastic film, but a polyethylene terephthalate film is suitable, and the thickness is 9 to 16 μm.
m can be used.

Various adhesives can be used for the adhesive layer 5, but an adhesive suitable for bonding by a dry laminating method or a non-sol laminating method is suitable. In addition, curling can be reduced during manufacturing.

Hereinafter, specific examples of the present invention will be described.
A coating layer 2 made of high-density polyethylene, 10 μm thick, on both sides of a central layer 1 having a thickness of 80 μm, high-density polyethylene mixed with polypropylene and calcium carbonate,
Heat-resistant film made of a 12 μm-thick polyethylene terephthalate film by dry lamination using a two-component curable urethane-based adhesive on both sides of the base material layer 4 6 and 6 were laminated, and a sealant layer 8 made of a low-density polyethylene film having a thickness of 50 μm was laminated on one side by the same adhesive and laminating method as described above to obtain a laminated material. This laminated material has a diameter of 73 m.
The sheet material was punched out into a circular shape of m, and a sheet-like lid material was prepared. When left in a room at 50 ° C. for 30 minutes, no curling occurred and the material was suitable as a lid material.

At the same time, as shown in FIG. 2, a heat-resistant film 6 is provided only on one side of the center layer 1 of the lid material, and the same as above is provided on the side of the center layer 1 where the heat-resistant film 6 is not provided. The laminated material provided with the sealant layer 8 of
The sheet material was punched out into a circular shape of mm to obtain a lid material of a single sheet. When this lid material was tested under the same conditions as described above, curling occurred with both sides on the sealant side floating by 30 mm.

[0017]

As described above, according to the present invention, even a lid material having a laminated structure without using aluminum foil has a certain rigidity, is hard to curl, and has a shape-retaining property. It is possible to cope with a single-wafer type feeding one by one or a continuous type feeding from a roll-shaped film. Also,
Since the aluminum foil is not used, it is possible to use a metal detector for inspecting whether a metal piece is mixed or not, thereby improving safety.

A sheet material for supplying a cover material punched into a predetermined shape, which is made of a laminated material that does not use a paper layer, is hardly affected by the external environment, does not curl even under high humidity conditions, and Can be sealed. Further, there is no possibility that bubbling will occur due to expansion of air in the paper layer and evaporation of water during sealing.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a laminated structure of a lid material of the present invention.

FIG. 2 is a sectional view showing a comparative example of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Center layer 2 ... Coating layer 4 ... Base material 6 ... Heat-resistant film 8 ... Sealant layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI B65D 53/04 B65D 53/04 A // B29K 23:00 67:00 B29L 9:00 31:56

Claims (5)

[Claims] 1. A co-extruded film having both sides of a central layer made of high-density polyethylene and a polypropylene-based polymer provided with coating layers made of high-density polyethylene,
A lid material, wherein a laminated material having a sealant layer provided on a lower surface of a laminated base material on which a heat-resistant film is laminated is punched into a predetermined shape. 2. The lid material according to claim 1, wherein the center layer of the base material is a high-density polyethylene / polypropylene polymer and further contains an inorganic filler. 3. The thickness ratio of the center layer / coating layer of the base material is 6 to 8
The lid material according to any one of claims 1 and 2, wherein the thickness is in the range of / 2 to 1. 4. The cover according to claim 1, wherein the heat-resistant film is a polyethylene terephthalate film. 5. The lid material according to claim 3, wherein the heat-resistant film is thiminated to the substrate by either a dry lamination method or a non-sol lamination method.