JPS5831113B2 - Composite adhesive sheet and its usage - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a composite thermoadhesive sheet having a novel structure with excellent adhesive strength and a method for producing the same.

As sheet adhesives, thermoplastic type so-called hot melt type adhesives and thermosetting type fiber base material impregnated type adhesives are known.

A hot-melt adhesive sheet using a thermoplastic resin is usually produced as a uniform sheet by means of melt extrusion, calendering, etc. by adding appropriate auxiliary agents.

In addition, thermosetting type base material-impregnated adhesive sheets are made by blending thermosetting resin with a curing agent and appropriate auxiliary agents, dissolving it in a solvent, impregnating it into a fiber base material, and drying it to form a uniform resin layer. It was manufactured as a sheet with a

That is, in the conventional method, a homogeneous sheet is created by melting or fusing one or more raw materials, which makes it difficult to improve the adhesive strength of the raw materials used, and in some cases requires the aid of a primer.

Furthermore, especially in the case of thermosetting resins, solvents are used, which is undesirable from the standpoint of resource saving and pollution-free production, and since fiber base materials are used, the adhesive sheet has high hygroscopicity and thick film thickness. It had drawbacks such as.

In view of these circumstances, the present inventors conducted intensive studies to improve the adhesive strength of the raw materials used without using solvents or fiber base materials, and as a result, they arrived at the present invention.

That is, in the present invention, a resin sheet having an average particle size of 5 to 1000 and having a melting point lower than that of the sheet is coated on one or both sides of a resin sheet that is self-supporting at least at room temperature but melts when heated.
The present invention relates to a composite adhesive sheet characterized in that a resin powder of μ is fixed by heating, and the powder and the resin sheet are mixed during heat bonding to form a uniformly dispersed form; The invention provides a composite adhesive in which a resin powder having an average particle size of 5 to 1000 μm and having a melting point lower than that of the sheet is fixed by heating on one or both sides of a resin sheet that is self-supporting at least at room temperature but melts when heated. A method of using a composite adhesive sheet, the sheet being heated to a temperature higher than the melting point of the resin sheet during adhesion to an adherend, so that the powder and the resin sheet are mixed and formed into a uniformly dispersed form for adhesion. It is something.

When producing the composite adhesive sheet of the present invention, a resin sheet that has a sheet or film shape at room temperature is used as a base, and an average particle size of 5 to 1
000μ resin powder is placed on a base sheet by means such as electrostatic method or scattering method, and then heated to a temperature below the melting point of the base sheet and above the melting point of the resin powder to fix the resin powder on the base sheet. can.

As the resin forming the base sheet used at this time, polyethylene, ethylene-vinyl acetate copolymer, nylon, polyester, polypropylene, etc. are used.

The resin powder to be applied is selected from among thermoplastic and thermosetting resins such as polyethylene, ethylene-vinyl acetate copolymer, nylon, polyester, epoxy resin, and polyimide resin, which have a lower melting point than the base sheet resin. However, it is preferable that the average particle diameter is in the range of 5 to 1000 μm in terms of uniform arrangement and heating conditions.

In the adhesive sheet of the present invention, at high processing temperatures, the resin powder component acts as a primer and improves the wettability of the adherend surface, and also mixes with the base sheet during heat bonding and takes on a uniformly dispersed form. .

The reason why the adhesive strength improves when the adhesive sheet maintains a uniformly dispersed form is unknown, but it is probably because, as mentioned above, the interfacial adhesive strength with the adherend surface is good, which leads to cohesive failure of the adhesive sheet. It is thought that the adhesive strength is improved because the adhesive strength is maintained up to

Therefore, in this bonding mechanism, the bonding temperature must be higher than the melting point of the base sheet.

The ratio of the base sheet forming resin to the powder resin described above varies depending on various combinations, but the weight ratio is usually 1:0.
．． They can be used in a ratio of 1 to 1:10.

Further, the thickness of the base sheet is not particularly limited, but a sheet having a thickness of 5 to 150 μm can be suitably used.

The adhesive sheet of the present invention may contain auxiliary agents such as plasticizers, fillers, pigments, fluidity regulators, and foaming agents, as necessary, and resin powder may be placed on one or both sides of the base sheet. You can leave it there.

The details of the present invention will be explained below using Examples.

In addition, parts mean parts by weight.

Example 1 0.3 parts of 2-methyl-imidazole was added to 100 parts of Epicor #1002 (epoxy resin manufactured by Shell Chemical Co., Ltd.) on a polyethylene film having an MI of 20, a melting point of 106°C, and a thickness of 15 μm, and the mixture was kneaded and then ground. The obtained epoxy resin powder (average particle size 80μ) with a melting point of 80°C was heated to 75? After spraying at a ratio of 0.25 m/m, the powder was fixed by heating at 90° C. for 10 minutes to obtain a composite adhesive sheet.

This composite adhesive sheet was sandwiched between two aluminum plates with a thickness of 0.6 mm, heated and bonded at 150°C for 30 minutes, and the 90 degree peel adhesive strength was measured based on JIS-6854, and it was 4 kg 725. The value of in is shown, and when the above resin powder is sprinkled on one of two aluminum plates at a rate of 80P/m' and then the aluminum plates are bonded together in the same way, 2 ky7
It was observed that the adhesive force was improved compared to that of 25 mm.

In addition, when observing the peeled surface of the adhesive part after measuring the peel adhesion force,
In the case of the composite adhesive sheet of the present invention, polyethylene is dispersed in the form of islands in the epoxy resin layer, and cohesive failure occurs in large island portions of polyethylene.
When only the resin powder was used, the surface to which the epoxy resin layer was attached simply suffered interfacial destruction.

Example 2 Surlyn AD5001 (manufactured by DuPont, MI20, melting point 96°C) was electrostatically coated to obtain a 100μ film.

On the other hand, a solution obtained from 100 parts of lipoxy resin VR60X (epoxy resin-acrylic acid adduct) manufactured by Showa Kobunshi Co., Ltd., 0.5 parts of methyl ethyl ketone peroxide, and 100 parts of acetone was spray-dried, and the average particle size was 40 μm. A powder (melting point 76°C) was obtained.

Lipoxy resin powder was then sprinkled onto the Surlyn AD 5001 film at a rate of 100 P/m', and then 8
A composite adhesive sheet was obtained by heating at 5° C. for 10 minutes.

This composite adhesive sheet was sandwiched between aluminum plates and heated at 150℃ for 30 minutes.
After heating and adhering for 30 minutes, we measured the 90 degree peel adhesion strength and found that it was 8.
6 kg/25 mm, and 5.2 kg/25 mrn for lipoxy resin powder alone, Surlyn AD
4.3 kg/mrr for 5001 film alone
It was better than t.

In addition, when observing the peeled surface of the adhesive part after measuring the peel adhesion force,
In the case of the composite adhesive sheet of the present invention, Surlyn AD5
Lipoxy resin was dispersed in dots in the layer of 001.

Example 3 Dumilan D-159 (manufactured by Mitsui Polychemical Co., Ltd., M11
5. A 100μ thick film of partially saponified ethylene-vinyl acetate copolymer (melting point 102°C) was coated with nylon powder Bratamide H-003P (melting point 80°C, average particle size 80μ) at 50°C. /m and then at 90°C.
A composite adhesive sheet was obtained by heating for 10 minutes.

This composite adhesive sheet was sandwiched between aluminum plates, and then
After heating at 20° C. for 5 minutes and adhesion, the adhesive strength at 90° peeling was measured and found to be 14 kg/25r/L11L, which was better than the case of Dumilan and nylon alone.

In addition, when observing the peeled surface of the adhesive part after measuring the peel adhesion force,
In the case of the composite adhesive sheet of the present invention, Dumilan D-
Nylon resin was dispersed in islands in the 159 layer.

Claims (1)

[Scope of Claims] 1 A resin powder having an average particle diameter of 5 to 1000 μm and having a melting point lower than that of the sheet is fixed by heating on one or both sides of a resin sheet that is self-supporting at least at room temperature but melts when heated. 1. A composite adhesive sheet characterized in that the powder and the resin sheet are mixed and uniformly dispersed during heat bonding. 2. The composite adhesive sheet according to claim 1, wherein the self-supporting resin sheet is made of a thermoplastic resin. 3. The composite adhesive sheet according to claim 1.2, wherein the resin powder is made of a thermoplastic resin or a thermosetting resin composition. 4. A composite adhesive sheet that is self-supporting at least at room temperature, but melts when heated, and a resin powder having an average particle size of 5 to 1000 μm and a melting point lower than that of the sheet is fixed by heating on one or both sides of the sheet. A method of using a composite adhesive sheet, which is heated to a temperature higher than the melting point of the resin sheet at the time of adhering an adherend, so that the powder and the resin sheet are mixed, uniformly dispersed, and adhered.