JPH0211331Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an easy-to-open packaged article that has appropriate heat-sealing strength and an opening that is convenient for opening.

As a function of the packaging material, it is desired that the package has sufficient heat-sealing strength to protect the contents, and that it can be easily opened to remove the contents.

Examples of easy-to-open packaging products include those made by heat-sealing an ionomer and low-density polyethylene, and those made by heat-sealing a polymer blend of polyisobutylene and ethylene-1-butene copolymer and polypropylene. There are easy-to-open packaged products made by sealing, and easy-to-open packaged products by heat-sealing propylene polymer and ethylene-vinyl acetate copolymer. Because the work is difficult and because heat sealing uses incomplete fusion, oil, water, and
When alcohol penetrates, the heat-sealing strength is significantly reduced, resulting in interfacial peeling, which has the drawback of being opened during transportation and storage.

The present invention solves the conventional drawbacks and provides a packaged article having appropriate heat-sealing strength and an opening convenient for opening, and will be described below with reference to the drawings.

The lid material 1 includes a polypropylene resin 3 on a base material 2.
and ethylene-vinyl acetate copolymer 4 to form a heat-sealing layer, and heat-resistant printing ink is partially printed on the ethylene-vinyl acetate copolymer 4 to form a non-heat-sealing layer. 5
It is a laminate made of

The base material 2 may be paper, cellophane, plastic film, metal foil, nonwoven fabric, or a composite material thereof.

Coextruded films are manufactured by conventionally known coextrusion methods. Specifically, polypropylene and ethylene-vinyl acetate copolymer are separately fed to two or more extruders, and the laminar flow of the melted resin is superimposed inside or outside the die to form a multilayer structure, and then a single sheet is formed. It is cooled and formed into a film.

Polypropylene can be extruded and is a copolymer or multi-component with ethylene, butene-1, pentene-1, etc., or a polypropylene and polyethylene, polybutene-1, polypentene-1, etc.
These include ethylene-vinyl acetate copolymer, a blend with ethylene-butene-1 copolymer, or unsaturated carboxylic acid-modified polypropylene.

Ethylene-vinyl acetate copolymers are copolymers that can be extruded and have an ethylene content of 70 mol% or more, or ethylene-vinyl acetate, vinyl alcohol terpolymers, ethylene-vinyl acetate, and unsaturated carboxylic acids. It is a modified terpolymer, a quaternary copolymer of ethylene-vinyl acetate, vinyl alcohol and an unsaturated carboxylic acid, or a blend thereof.

Methods for laminating coextruded films onto various substrates 2 include lamination or thermal lamination in which films are laminated using a known melt-extrusion coating adhesive.

Printing ink is a printing ink in which resins such as alkyd, nitrocellulose, polyester, polyether, polyurethane, polyamide, cyclized rubber, vinyl chloride-vinyl acetate copolymer, and chlorinated polypropylene are dissolved and dispersed in a solvent as a binder. The ink film layer dried after solvent evaporation has a melting point that is at least higher than the melting point of the ethylene-vinyl acetate copolymer 4, or has heat fusion with the ethylene-vinyl acetate copolymer 4. It's something you don't do. Printing on coextruded films includes conventional methods such as gravure printing, flexographic printing, and screen printing. In order to improve the adhesion between the ethylene-vinyl acetate copolymer 4 and the printing ink, surface treatments such as corona discharge treatment and primer coating treatment may be performed.

The container body 6 may be a laminate in which an ethylene copolymer 8 is laminated on a base material 7 as shown in the figure, or may be a single sheet of an ethylene copolymer, and may be formed by conventional pressure forming or vacuum forming. By legal means,
Alternatively, it is a container with a flange formed around the opening using adhesive or heat sealing.

The base material 7 may be paper, cellophane, plastic film, metal foil, nonwoven fabric, or a composite material thereof.

The ethylene copolymer 8 is polyethylene, an ethylene-α olefin copolymer, an ethylene-vinyl ester copolymer, a modified ethylene-vinyl acetate copolymer, or a copolymer of ethylene with acrylic acid, maleic acid, or itaconic acid. or an ionomer resin obtained by ionically crosslinking the same.

Commonly used methods for laminating the film onto the base material 7 include a melt extrusion coating method, a lamination method in which films are bonded together via an adhesive, and a thermal lamination method.

Hot plate heating is a technique for filling the container body 6 with contents and heat-sealing the lid material 1 to the flange of the container body 6 to form a hermetically packaged article with appropriate heat-seal strength and an opening convenient for opening. Seal method,
There are heat sealing methods such as impulse sealing method and ultrasonic sealing method.

Next, FIGS. 2 to 4 show the state in which the packaged article in which the lid material 1 is heat-sealed to the flange of the container body 6 is opened.
This will be explained with a diagram.

Non-heat sealing layer 5 in heat sealing area A
Since the space between the ethylene-vinyl acetate copolymer 4 and the flange cannot be heat-sealed, a convenient opening is formed when opening the package, and the space between the ethylene-vinyl acetate copolymer 4 and the flange can be heat-sealed to provide appropriate heat-sealing strength during storage and handling. form. When opening the container, hold the lid 1 with your fingers and peel it off from the flange of the container body 6.
First, the ethylene-vinyl acetate copolymer 4 breaks at point 9 along the line from point 9 to point 10, and then at point 1.
At 0, delamination between the polypropylene resin 3 and the ethylene-vinyl acetate copolymer 4 occurs along the line from point 10 to point 11. Next, at point 11, the ethylene-vinyl acetate copolymer 4 is broken along the line from point 11 to point 12, and the lid 1 is opened. By forming the non-heat-sealing layer 5 with heat-resistant printing ink and providing a portion where stress is concentrated upon opening, it is possible to reduce the initial peel strength and make opening easier.

This invention is applicable to skin pack containers, blister pack containers for confectionery, meat, medicine, toys and household goods.
Applicable to vacuum packaging containers.

Examples of the present invention will be described below.

Example 1 A coextrusion extrusion laminator was used to coat polypropylene (Showa Denko Co., Ltd.) on a base material 2 of biaxially oriented polypropylene film (Toray Industries, Inc., Torayuan BO#2535, 25μ). 7.0) 3 and ethylene-vinyl acetate copolymer (Mitsui Polychemical Co., Ltd. Evaflex d = 0.93 MI = 3.0) 4 were laminated to form a two-layer film with a thickness of 26μ and 4μ, respectively, and a total thickness of 30μ.
A heat-resistant transparent ink containing chlorinated polypropylene as the main binder (Dainippon Ink & Chemicals Co., Ltd.
A non-heat-sealing layer 5 was formed by partially printing TAF-SP heat-resistant PC, manufactured by Co., Ltd., to produce a lid material 1.

On the other hand, the base material 7 of an unstretched hard polyvinyl chloride sheet (Mataei Kako Co., Ltd. 200μ) was treated with a polyethyleneimine primer (Showa Denko Shorex d=0.92 MI=2.5).
After extrusion coating and laminating a polyethylene layer with a thickness of 30 μm, a container body 6 having a flange around the opening was produced by pressure molding.

Layer the flange of the lid material 1 and the container body 6, and heat at 150°C.
Kg/cm ² Heat sealing was performed for 1 second, and the heat sealing strength was measured to be 0.8 Kg/inch.

Since the non-heat-sealing layer 5 was formed on the lid 1, a portion of the flange of the container body 6 facing inward from the outer periphery was not heat-sealed to the lid 1.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the state immediately before the lid material is placed on the container body, FIGS. 2 to 4 are cross-sectional views showing the state in which the lid material is peeled off from the container body 6, and FIG. 1 is a perspective view showing an example of a packaged article according to the present invention. 1... Lid material, 6... Container body.

Claims (1)

[Scope of utility model registration request] In a packaged article consisting of a container body filled with contents and having a flange formed around the opening, and a lid material that is placed over the container body and heat-sealed to the flange of the container body, the lid material is By printing with heat-resistant printing ink on the heat-sealing layer, a non-heat-sealing layer is formed partially inward from the outer periphery of the lid material, so that the flange of the container body moves inward from the outer periphery. A packaging article characterized in that it is not partially heat-sealed with a lid material.