JPS59140049A - Easy-open cover material for glass vessel - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to a lid material for easy-open sealed packaging.

Currently, there are only a few lidding materials that can be used for sealed packaging with glass containers, such as paper coated with water-soluble glue or hot-melt adhesive coated on the base material.
The contents are limited to dry solids and are not easy to open.

Generally, when sealing liquid contents in a container, the container is filled with the contents, and then the lid and container are heat-sealed.
Seal. In this case, since it is impossible to completely eliminate liquid dripping from the filling nozzle and the like when filling the contents, there is a high possibility that the liquid will adhere to the flange, which is the part of the container that is heat-sealed. Therefore, a sealant with good foreign substance sealing properties is desired. In addition, with current heat sealing, the temperature of the mold for the heat seal reservoir varies widely, so a sealant that can be easily opened and has a wide heat seal temperature range is desired. In other words, the optimal sealant for the lid material is one that is easy to open, has a wide heat-sealing temperature range, and has good heat-sealability against contaminants.

As a result of research to develop a lidding material with the above-mentioned suitability, the present inventor has chemically applied an ethylene-vinyl acetate copolymer to a base material made of a heat-resistant plastic film or metal foil by hydrolysis or graft polymerization. By providing a sealant layer made of a multi-component copolymer that has been denatured, the heat-sealing temperature range is wide and the heat-sealing temperature range is wide, and the sealant layer has good resistance to contaminants and heat-sealing, and it is also sealed against liquid contents. The inventors have discovered that it is possible to heat and seal most glasses such as ordinary soda lime glass and borodic acid glass, and that pretreatment of the glass surface is not required at all. The present invention has been completed based on this.

That is, the gist of the present invention is to apply a sealant made of a multicomponent copolymer chemically modified by hydrolysis or graft polymerization of ethylene-vinyl acetate copolymer to a base material such as a heat-resistant plastic film or metal foil. This is an easy-to-open lid material for a glass container.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 shows an easy-to-open lid material for glass containers of the present invention (sides are shown).

A sealant layer (2) made of a multicomponent copolymer obtained by chemically modifying an ethylene-vinyl acetate copolymer by hydrolysis or graft polymerization is provided on a base material (1) made of a heat-resistant plastic film or metal foil. It is being

Accordingly, in the present invention, as the base material (11), aluminum i which is a metal foil is most suitable, and heat-resistant plastic films such as polyethylene terephthalate stretched nylon, stretched or unstretched polyethylene, polycarbonate, polystyrene, and polyvinyl chloride may also be used. suitable.

Next, the sealant layer (2) provided on the base material (1) is a multicomponent copolymer obtained by chemically modifying an ethylene-vinyl acetate copolymer by hydrolysis or graft polymerization, that is, an ethylene-vinyl acetate copolymer. A partially saponified product of the union,
Acetoxy groups, those containing hydroxyl groups, and acetoxy groups,
It contains a hydroxyl group and a carboxyl group.

The above-mentioned sealant layer exhibits good heat-sealing properties for glass containers, and opening is due to interfacial peeling between the sealant and the glass surface. Therefore, compared to cohesive failure type sealants,
The flange is also very clean after opening. In addition, the above-mentioned sealant layer is firmly fused by heat-sealing, so there is no fear of bag breakage, and it has excellent contaminant-sealing properties.

In packaging containers for foods, etc., heat sealing does not peel off from the container and maintains ease of opening during handling during processing and distribution processes after live sealing. We know that it is given by the range. On the other hand, the heat sealing temperature varies depending on the performance of the sealer and actual packaging conditions, but
It is unavoidable that temperatures will vary between ~40°C. Therefore, it is required that the fusion strength be maintained within the above-mentioned preferred range over as wide a sealing temperature range as possible. The lid material of the present invention fully satisfies this requirement, as seen in the examples listed later.

The thickness of the sealant used in the present invention is 10μ to 150μ
μ is suitable, and 30 μ to 100 μ is optimal. If it is less than 10μ, the sealing property against foreign substances will be poor and the sealing strength will vary, which is undesirable. If it is more than 150, the sealing strength will be too strong and easy opening will not be achieved.

As detailed above, the lid material of the present invention has a wide heat-sealing temperature range for easy-open heat-sealing, has good contaminant heat-sealing properties, and maintains sealing performance even against liquid contents. Moreover, it has the advantage that it can be heat-sealed to most glasses such as general soda lime glass and borosilicate glass, and does not require any pretreatment of the glass surface.

Next, the present invention will be specifically explained with reference to Examples.

EXAMPLE A strong sealing material was prepared by corona treatment on the surface of a film of the following adhesive polyolefin resin with a thickness of 50 μm, and dry lamination with an adhesive on aluminum foil with a thickness of 40 μm.

O-adhesive polyolefin resin ethylene-vinyl acetate copolymer is chemically modified by hydrolysis and graft polymerization to create a multicomponent copolymer containing acetoxy groups and hydroxyl and carboxyl groups (Takeda Pharmaceutical Co., Ltd.)
Product name Demiran). Softening point 70℃, Ml 21'/
10m1n.

Density: 0.96'i/C1 This sealing material was heat-sealed to a float glass plate having a thickness of 3wx, and the sealing strength was measured using a Tensilon.

Q Heat sealing condition temperature 140.160.180.200.220.24
0°260°C Pressure 2.01 Hours 4 sec O Heat seal strength measurement conditions: 180° peeling, tensile speed 100 ml/min or higher The results are shown in Figure 2. The graph in the figure shows that the present invention has ease of opening over a wide range of heat sealing temperatures.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the lid material of the present invention, and FIG. 2 is a graph of heat sealing temperature versus heat sealing strength of the sealant layer of the lid material. (1)...Base material (2)...Sealant layer (3)...
... Lid material patent applicant Dai Nippon Printing Co., Ltd. Patent attorney Okimi Konishi

Claims (1)

[Claims] It is characterized by providing a sealant layer made of a multicomponent copolymer obtained by chemically encapsulating an ethylene-vinyl acetate copolymer by hydrolysis or graft polymerization on a base material such as a heat-resistant plastic film or metal foil. Easy-to-open lid material for glass containers.