JPS601099Y2 - Heat sealing lid material - Google Patents

Description

[Detailed Description of the Invention] The purpose of this invention is to improve a heat-sealing lid material that is tightly attached to the opening of a synthetic resin container for milk, lactic acid bacteria drinks, juices, detergents, etc. by heating.

In general, the requirements for heat-sealing lid materials are: 1. The lid can be peeled off cleanly without leaving any residue when removed from the mouth of the container. 2. It can be heat-sealed at low temperatures (70 to ITO℃) and in a short time (within 1 second). 3. It has a film layer that prevents corrosion of the aluminum foil. 1. 4. It can keep the container airtight due to its cushioning properties.

By the way, the heat-sealing lid materials that have been proposed so far do not satisfy the above requirement 1 because the adhesiveness between the aluminum foil and the heat-sealing adhesive layer is insufficient. If the mouth of the resin container has an uneven surface, there is a problem in that Requirement 4 is not satisfied.

This invention solves the above-mentioned problems and provides a heat-sealable lid material that meets the above requirements. In order to be able to peel off the aluminum foil cleanly, a heat-sealable adhesive layer containing an ethylene-vinyl acetate copolymer as a main component is provided on one side of the aluminum foil. The layer thickness is based on a non-crystalline, thermoplastic, high molecular weight linear saturated polyester resin as the main component, and the layer thickness is based on chlorinated polyethylene as an adhesion mediating layer between this resin layer and the hot melt layer. By interposing a resin layer of 3μ or more, it is possible to heat-seal various synthetic resin containers as a lid material using a hot-melt adhesive as a heat-sealing adhesive.

In the second invention, in order to prevent the hot melt adhesive from remaining on the mouth of the container when the lid is opened, a linear saturated polyester resin is used on the aluminum foil side as an adhesion mediating layer between the aluminum foil and the hot melt adhesive layer. The hot melt adhesive layer side has a chlorinated polyethylene resin layer, and these polyester resin and polyethylene resin layers serve as an adhesion mediating layer between the aluminum foil and the hot melt adhesive. In addition to this function, by making sure that the total thickness of these two layers is 3μ or more, the lid material can completely adhere to the uneven surface of the synthetic resin container opening during heat sealing. This makes it possible to provide cushioning properties.

The linear saturated polyester resin preferably has a molecular weight of 10.000 to 20.000.
□□ and 30 with molecular weight 20.000-30.000
It is preferable to use a blend resin having a width of 9 to 9.

This is because when substances with a molecular weight of 10,000 to 20,000 cross the state capital, blocking is likely to occur;
This is because if the number is less than 3Cs, the adhesive strength with aluminum foil tends to be weak.

Next, various embodiments of each layer related to the above-mentioned conditions will be explained.

Note that all percentages and parts of each component in this specification are by weight.

First, in order to eliminate adhesive residue at the container opening when the lid is opened, it is possible to prevent breakage within the adhesive layer by increasing the cohesive force of the hot melt adhesive used. As the cohesive force increases, the melting point and viscosity of the adhesive itself increases, which impairs the adhesive's low-temperature, short-time heat sealing properties and makes it difficult to apply the hot melt adhesive. The difficulty of high viscosity and high temperature increases, and the adhesion to non-porous aluminum foil also decreases.
It can be seen that there is a limit to preventing adhesive from remaining in the mouth of the container by changing only the hot melt adhesive.

Based on the above, in this invention, an attempt was made to make this possible by using an adhesive agent that has a stronger adhesive force than that between the aluminum foil and the hot-melt adhesive.

Experimental Example 1 A single layer of vinyl chloride resin was tried as an adhesion mediating layer, but the adhesive strength and water resistance were good, but the result was poor mouthfeel.

The coating composition at that time was 20 parts of VMCH (trade name of Union Carbide Co., Ltd.) VYHH (same as above) α fast solvent.
There are 120 copies.

Experimental Example 2 A resin layer was prepared by mixing 65 parts of polyethylene resin with a degree of chlorination of 25 to 27% and 35 parts of modified polyester with ethylene glycol in a single layer as an adhesion mediating layer. There wasn't enough for the rest.

Experimental Example 3 A single layer of chlorinated polyethylene resin was used as an adhesion mediating layer to examine its effectiveness.

That is, a toluene solution of various substances with a degree of chlorination of 35% or less and a solid content of 18% or less is applied to aluminum foil, and when the solid content is applied in an amount of 3 g/rr1 or more, this chlorinated polyethylene resin A performance test similar to the one described above was conducted in which a hot melt adhesive mainly composed of ethylene-vinyl acetate copolymer and paraffin wax was applied to the surface of the layer, but sufficient effects were not obtained, and the hot melt adhesive did not close to the mouth of the container. I remained in the club.

Experimental example 4 Molecular weight of high molecular weight saturated polyester resin 15°000~
25.000 and polyethylene with a degree of chlorination of 35% or less and applied it to aluminum foil as an adhesion mediating layer for hot melt adhesive. It had no effect.

Experimental Example 5 The following was tried using a high molecular weight linear saturated polyester resin as an adhesion mediating layer as described above.

That is, a mixture of 60% of molecular weight 20.000 to 25.000 and 40% of molecular weight 15.000 to 20.000 was applied, but the adhesion was excellent, but hot Melt adhesive remained at the mouth of the container.

Example 1 Using the above experimental examples as a reference, we created a product with strong adhesive strength, water and corrosion resistance, and no hot melt adhesive left on the mouth of a synthetic resin container when the lid was opened. .

That is, first, an amorphous plastic high molecular weight linear saturated polyester resin with a molecular weight of 15.0 is applied to the aluminum foil surface.
00-20.000, 10-70%, molecular weight 2
A mixture of 30 to 90% of 0.000 to 25.000 was applied to form a film with a thickness of about 3 microns, and on top of that a layer of polyethylene resin with a chlorination degree of 25 to 27% was applied.
A hot melt adhesive containing 4 parts of paraffin wax, 35 parts of ethylene-vinyl acetate copolymer, and 15 parts of a polar group-containing synthetic resin is applied on top of the top coat to form a μ film ( When the performance was tested by heat-sealing the openings of various synthetic resin containers, satisfactory results were obtained.

Similarly, the inorganic material is added to the amorphous thermoplastic high molecular weight linear saturated polyester resin of the undercoat from 0.01% to 20%, and the melamine resin is added from 0.01% to 10%, hereinafter vinyl chloride-vinyl acetate copolymer. The same effect can be obtained by adding 0.01 to 5% of coalescence and 15% or less of alkyd resin or rosin, or adding about 3% or less of 1 coronate L of Tasumi polyurethane as an isocyanate compound. showed that.

Furthermore, it was also possible to mix various resins with the chlorinated polyethylene resin used as the top coat.

That is, polyolefins and their derivatives and their ethylene-propylene copolymers, EVA1 polyisobutylene, Hypalon, polychloride resins, vinyl chloride-vinyl acetate copolymers, PVDC1 natural or synthetic rubbers, rosin-modified ranges, etc. can also be used. The addition of each of these is limited to 10% or less, and adding too much will result in a decrease in performance.

Note that the lid material of this invention can also be heat-sealed to containers made of materials other than synthetic resin.

Next, one embodiment of this invention will be described based on the drawings.

FIG. 1 shows the lid 1 of this invention heat-sealed to a lactic acid bacteria beverage container 7. As shown in FIG. A polyester resin layer 4 mainly composed of polyester resin is laminated, and a chlorinated adhesive is applied between this polyester resin layer 4 and a hot melt adhesive 6 mainly composed of ethylene-vinyl acetate copolymer and wax. This is achieved by interposing an adhesion mediating layer 5 made of polyethylene resin.

As explained above, since the core material of this invention has a resin layer of linear polyester chlorinated polyethylene, it is possible to eliminate the residue at the container opening when the lid is opened, and it also has a low-temperature hot-melt adhesive. Since the adhesive can be used, heat sealing can be performed at low temperatures and in a short time.

Furthermore, since the adhesive mediating layer has a thickness of 3μ or more, it has good cushioning properties and can adhere even to uneven container openings, as well as excellent water resistance and corrosion resistance. It has a great effect.

[Brief explanation of drawings]

FIG. 1 is a perspective view of the lid material of this invention in a heat-sealed state, and FIG. 2 is a sectional view taken along the line ■--■ in FIG. 1. In the figure, 3: aluminum foil, 4: curved polyester resin layer, 5: curved polyethylene resin adhesive layer, 6: hot melt adhesive.

Claims (1)

[Scope of utility model registration request] When providing a heat-sealable adhesive layer mainly composed of ethylene-vinyl acetate copolymer and wax on one side of aluminum foil, a linear polyester resin is placed between the aluminum foil and the heat-sealable adhesive layer. The main component is a resin layer,
Further, a chlorinated polyethylene resin layer is interposed between this resin layer and the heat-sealable adhesive layer, so that the total thickness of the two layers forming the adhesion mediating layer is 3μ or more. A heat-sealable lid material.