JPS6212595Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to an aluminum foil composite material.

Conventionally, aluminum foil coated with a heat sealing agent has been widely used for packaging materials, lidding materials, and the like.

For example, (1) The packaging for medicines is generally made of a molded vinyl chloride sheet as a base, covered with coated aluminum foil, and sealed with heat sealing. (PTP packaging) (2) Solid or pasty foods such as jam, butter, and tyokolate are filled into molded containers made of vinyl chloride, heat-resistant vinyl chloride resin, styrene, etc., and the containers are heat-sealed with coated aluminum foil and used as lids. . (Blister Pack) (3) A paper cup or foamed polystyrene cup filled with ramen noodles, shiruko, etc., whose inner surface is coated with polyethylene, and then heat-sealed with coated aluminum foil to form a lid.

(4) A lactic acid drink such as sour or yogurt placed in a molded polystyrene cup and covered with aluminum foil.

However, most of these are made by filling a molded container using vinyl chloride or polystyrene as a base material with aluminum foil coated with a heat-sealing agent, and then heat-sealing the container as a lid material.

Instead of base materials such as vinyl chloride and polystyrene mentioned above, polypropylene resin, which has low moisture permeability, heat resistance, and stiffness, is used as a base material, and aluminum foil and polypropylene film are bonded together. Research has been conducted on lids for polypropylene containers and aluminum foil molded containers (with polypropylene film laminated on the inside), but these have the following drawbacks: (1) The lid cannot be opened by hand to remove the contents.

(2) High cost.

(3) Heat sealing temperature is high because polypropylene is fused together.

These problems have been pointed out as drawbacks, and the current situation is that it has not yet been put into practical use.

From the above, heat sealability should be good for polypropylene film or sheet molded products and molded containers using composite materials whose heat sealing surface is polypropylene.

No decrease in heat sealing strength over time in various atmospheres.

Must be heat resistant, water resistant, and steam resistant.

Avoid blocking when wound into a coil.

There is a demand for an aluminum foil composite material as a lid material having the following properties.

Therefore, the object of this invention is to provide an aluminum foil composite material with good heat sealability for polypropylene molded containers.

This invention will be explained below based on the attached drawings.

The aluminum foil composite material of this invention has a mixed resin layer 2 of polyacrylate resin and polymethacrylate resin on the back side of aluminum foil 1.
A mixed resin layer 3 of a chlorinated isotactic polypropylene resin and an epoxy resin is laminated via a chlorinated isotactic polypropylene resin and an epoxy resin.

As mentioned above, this invention uses a mixed resin of chlorinated isotactic polypropylene resin and epoxy resin as a resin that adheres well to polypropylene containers, and to achieve adhesion between this mixed resin and aluminum foil. A mixed resin of a polyacrylic ester resin and a polymethacrylic ester resin is interposed therein.

The above-mentioned chlorinated isotactic polypropylene resin is obtained by chlorinating ordinary isotactic polypropylene, and the degree of chlorination is preferably within the range of 10 to 45%, and if it is less than 10%, the solubility in organic solvents will be poor. Not only is it not possible to obtain stability as a solution, but also a uniform coating film cannot be obtained, and 45%
Above this, the adhesion to polypropylene decreases, and as a result, the heat sealing strength decreases, making it impossible to obtain an aluminum foil composite material suitable as a lid material for polypropylene containers. By adding an epoxy resin to this chlorinated isotactic polypropylene, it is possible to increase the cohesive force of the chlorinated isotactic polypropylene resin layer and prevent the heat seal strength from decreasing over time. From the point of view of compatibility, 70 to 95% chlorinated isotactic polypropylene to 5 to 95% epoxy resin.
30% is appropriate.

In addition, when bonding aluminum foil and chlorinated isotactic polypropylene, it goes without saying that the resin has adhesive properties to both, but since chlorinated isotactic polypropylene has crystallinity, heat sealing is necessary. Even after being melted and cooled by heat sealing, crystallization tends to progress gradually if left in an atmosphere of 20 to 60°C. A mixed resin of an amorphous polyacrylic ester resin and a polymethacrylic ester resin is used as a resin that does not reduce the adhesiveness of the interface with polypropylene.

Also, there are no particular limitations on the aluminum foil.
There is no problem even if it is printed 4 or pasted with paper or plastic.

When the aluminum foil composite of this invention obtained as described above is used as a lid material for a polypropylene molded container, it exhibits the excellent performance listed below.

(1) Good heat sealability with polypropylene.

(2) There is no decrease in heat sealing strength in various atmospheres.

(3) Good water resistance.

(4) It can withstand hot packs and has good heat and steam resistance.

(5) No blocking.

[Brief explanation of the drawing]

The drawing is a sectional view showing an embodiment of the aluminum foil composite material according to this invention. 1... Aluminum foil, 2... Mixed resin layer of polyacrylic ester resin and polymethacrylic ester resin, 3... Mixed resin layer of chlorinated isotactic polypropylene resin and epoxy resin.

Claims (1)

[Scope of utility model registration request] An aluminum foil composite material made by laminating a mixed resin layer of chlorinated isotactic polypropylene resin and epoxy resin on the back side of aluminum foil via a mixed resin layer of polyacrylic ester resin and polymethacrylic ester resin.