JPH0214130A - Control method for bonding strength - Google Patents

Abstract

PURPOSE:To control bonding strength simply and accurately by forming at least a primer for either increasing bonding properties or lowering the same by means of given area ratio when two bonding materials to be bonded together are bonded with a bonding agent. CONSTITUTION:For example, one material to be bonded 11 is a fluorine resin film, while the other material to be bonded 12 is an aluminum foil, and a bonding agent layer 13 and two printer layers 14 and 15 are provided between the fluorine resin film 11 and the aluminum foil 12. The bonding agent layer 13 is composed of a hotmelt bonding agent. One primer layer 14 is constituted of a bonding agent layer 13 and an anti-corrosion film of good affinity and wetting properties, for example, a chlomate or zirconium film for covering the front surface of the aluminum foil 12. The other primer layer 15 is constituted of a bonding agent layer 13 and silicon resin of poor affinity and wetting properties, which is scattered over between the bonding agent layer 13 and one primer layer 14. Bonding strength is controlled by varying the area ratio of a coating section and uncoated section of the primer.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of controlling adhesive strength, and more particularly to a method of controlling adhesive strength so that sealability and unsealability are simultaneously satisfied in food containers and the like.

Conventional methods for controlling adhesive strength include selecting the type of adhesive resin, blending, polymer alloying, copolymerization, etc.; setting conditions such as adhesive time, temperature, and pressure;
It is known that this is achieved by applying a multilayer coating or by selecting the type of ground surface treatment.

Problems to be Solved by the Invention No matter which of the above-mentioned methods is employed, variations occur in adhesive strength, making it difficult to stably obtain a desired adhesive strength.

An object of the present invention is to provide a method for controlling adhesive strength that solves the above problems.

Means for Solving the Problems The method for controlling adhesive strength according to the present invention is such that when two adherends are bonded together with an adhesive, an adhesive is applied to the surface of at least one of the two adherends. A coated portion and an uncoated portion of at least one of a primer that improves the adhesiveness of the agent and a primer that decreases the adhesiveness are formed at a predetermined area ratio.

Example Embodiments of the invention will now be described with reference to the drawings.

In FIGS. 1 and 2 two adherends 11.12 are shown which have been glued together in the method according to the invention. One adherend 11 is a fluororesin film, and the other adherend 12 is aluminum foil. An adhesive layer 13 and two primer layers 14 and 15 are interposed between the fluororesin film 11 and the aluminum foil 12. The adhesive layer 13 is made of hot melt adhesive. One primer layer 14 is an anticorrosion coating having good affinity and wettability with the adhesive layer 13, such as a chromate or zirconium coating, and is present so as to cover the front surface of the aluminum foil 12. The other primer layer 15 is a silicone resin that has poor affinity and wettability with the adhesive layer 13, and is interspersed between the adhesive layer 13 and one primer layer 14. The adhesive strength of the portion between the fluororesin film 11 and the aluminum foil 12 where the silicone resin layer 15 is interposed is weaker than that of the other portion.

Next, the steps of the bonding method will be explained step by step.

a. A fluororesin film 11 having a thickness of 25 mm was used, and the entire surface of the film was coated with a hot melt adhesive 13 using a screen printing machine. Its thickness is 2
It was set as 0IyI.

b. On the other hand, A1100 material was used as the aluminum foil 12, and this was degreased with 5% NaOH.

After degreasing C1, the entire surface of the aluminum foil 12 is coated with
Ink 14 containing a silane coupling agent was printed using a screen printer. Note that instead of the ink 14 containing a silane coupling agent, a paint-on base film may be applied.

d. After the above ink 14 was dried, ink 15 containing fluororesin was printed thereon using the same screen printing machine. As shown in FIG. 3, the printing pattern consists of coated portions 21 having a circular outline and non-coated portions 22 arranged in a scattered manner. In this case, for comparison, as shown in Table 1, 5N type samples were prepared in which the pitch P of the coating portion 21 was constant and the diameter was varied. Further, the thickness of the coating portion 21 is preferably made as thin as possible in order to reduce spreading during sealing.

The film 11 treated as above 80 and the aluminum foil 12 were laminated and pasted together using a press. The pressure during pressing was 4.5 kgf/cj, the temperature was room temperature, and the time was 30 seconds.

The above bonding was performed for each of the five types of samples, and then the peel strength of each was determined by n1. The results are shown in Table 2 and FIG.

As is clear from Table 2 and FIG. 4, the adhesive strength can be controlled by changing the coating area of the primer.

In the above specific example, two types of primers are used, but only one type of primer may be used if, for example, there is no need to expect a corrosion-resistant effect from the primer.

Moreover, the coating pattern of the two types of primers is arbitrary.

(The following is a blank space) Effects of the Invention According to the present invention, adhesive strength can be easily and accurately controlled by changing the area ratio of the coated portion and non-coated portion of the primer.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention, and FIG. 1 is a sectional view of an adherend used in carrying out the invention, and FIG.
3 is an explanatory diagram of the primer coating pattern, and FIG. 4 is a graph showing the adhesive strength. 11, 12... Adherent, 13... Adhesive, 14.1
5...Primer, 21...Coating part, 22.
...Non-coated area. Patent applicant: Showa Aluminum Co., Ltd.
Person Einosuke Kishimoto (4 others) Figure 2 No(ri() D'')○○( Figure 3 Area of non-coated part Figure 4

Claims (1)

[Claims] When bonding the two adherends 11 and 12 with the adhesive 13, a primer that improves the adhesion of the adhesive 13 is applied to the surface of at least one of the adherends 11 and 12. 14 and the primer 15 that lowers the adhesion, the coated portion 21 and the non-coated portion 22 of at least one of the primers 14 and 15 are formed in a predetermined area ratio.