JPS6241467B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an aluminum plate material used for a bottle cap formed by drawing or an opening tab for an easy-opening lid.

It has already been done to produce bottle caps, opening tabs, etc. by drawing from aluminum plates whose surfaces have been degreased, then washed and dried. After being squeezed into a mold, the cap and tab take a long time to separate from the mold, which hinders processing operations and reduces production efficiency.

Of course, when using an aluminum plate that has been subjected to chromate treatment after degreasing, it is more difficult to use than an aluminum plate that has not undergone chromate treatment.
Although release from the mold was good, there was still some delay in release, and high-speed production of 300 pieces per minute could not be achieved.

The purpose of the present invention is to provide an aluminum plate material that can be released from a mold more quickly than a chromate-treated plate. α−
A surface treatment solution prepared by dissolving a water-soluble thermoplastic polymer resin consisting of an ammonium salt of a copolymer of olefin and α/β unsaturated carboxylic acid in water has a dry film weight of more than 0.01 g/m ² and 1.0 g/m2. Apply an amount within the range of m ² or less and dry to the point.

Next, examples of the present invention will be described.

Experimental example Ethylene-acrylic acid copolymer resin 220g, 28
% ammonia water/43g, deionized water 73.7g to 4.5
Kg/cm ² , kept at 130℃ and stirred for about 1 hour.
After solubilizing it in water, it was cooled and further adjusted to pH 9.5 ± 0.5 with 28% ammonia water to make a resin solution with a resin solids concentration of 22%, and this resin solution was diluted to a concentration of 1% with deionized water. Add a sheet of aluminum tab material (A5082, 0.35 mm
Thickness, H19) was immersed for 5 seconds at 25℃, squeezed with a rubber roll to a coating amount of 5g/ ^m2 , and then dried in a hot air atmosphere (140℃) for 5 seconds to remove moisture and reduce the amount of dry film. A test plate of 0.05 g/m ² was prepared.

Comparative Example 1 The same degreased and washed sheet aluminum tab material as in the experimental example was subjected to chromate treatment, which is conventionally applied to some tab materials, to produce a chromate film with a dry chromium adhesion amount of 0.02 g/ ^m2. Make a test board with

Comparative Example 2 A test plate was prepared using the same degreased and water-washed aluminum tab material as that used in the experimental example.

Next, the results of measuring the friction coefficients of the surfaces of the aluminum plates of Experimental Example, Comparative Example 1, and Comparative Example 2 will be shown.

The load was 0.6Kg Experimental example 0.081 Comparative example 1 0.173 〃 2 0.357 The friction coefficient of the aluminum plate of the present invention (Experimental example) that was surface-treated by the experimental example method was higher than that of the others (Comparative examples 1 and 2). It can be seen that the slip resistance is extremely low and the stickability is good. When a tab was formed using the aluminum material of the experimental example, the tab was easily separated from the processing punch and did not cause any problems during high-speed drawing processing.

Film weight 1.0g/ ^m2 and 1.5 using the same method as the experimental example
When tabs were manufactured from aluminum plates with a coating of 1.0 g/m ² , there was no problem in machining, but tabs coated with 1.5 g ^/ m ² had difficulty separating from the processing punch. It was hot.

In addition, α-olefins used in the surface treatment solution for aluminum plates include propylene, etc. in addition to those shown in the experimental examples, and α and β unsaturated carboxylic acids include methacrylic acid, maleic acid, etc. in addition to those shown in the experimental examples. be.

In addition, water-soluble thermoplastic polymer resin has an acid value of 30~
300 is preferred. If the acid value is less than 30, dispersion or solubility in water will be poor and it will be difficult to obtain a uniform film, and if the acid value is more than 300, the dried film will easily dissolve in water and corrosion resistance will be poor. Note that the surface treatment liquid used in the present invention is an aqueous solution of a water-soluble thermoplastic polymer resin in the form of an ammonium salt.
As exemplified in the above experimental example, a dry film with excellent water resistance can be obtained under heating conditions at a relatively low temperature and for a short time.

The container parts drawn from the aluminum plate of the present invention can be easily separated from the processing punch after drawing and can be produced at high speed, which improves the production efficiency during processing. It was found that there were no cracks or peeling, and the film was water resistant and had good corrosion resistance.

Furthermore, when the opening tab made of an aluminum plate of the present invention is riveted to the can lid and then wrapped around the can body, the sliding tab prevents the tab from rotating with respect to the can lid by contacting the seaming chuck. It also showed a special effect in that it could be prevented because of its good properties.

Claims (1)

[Claims] 1 The surface of the aluminum plate is degreased and washed with water, and then surface treatment is carried out by dissolving in water a water-soluble thermoplastic polymer resin consisting of an ammonium salt of a copolymer of α-olefin and α/β unsaturated carboxylic acid. The dry coating weight exceeds 0.01g/ ^m2 and is 1.0g/ ^m2.
An aluminum plate material for drawing processing characterized by being coated in the following amount and dried.