JPH10102012A - Production of polyimide resin adhesive film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain polyimide resin adhesive film having an excellent face to be coated by improving compatibility of the surface of the polyimide resin adhesive film with polyimide resin varnish. SOLUTION: This method for producing a polyimide resin adhesive film comprises coating one side or both sides of a film made of a polyimide resin with a thermally meltable polyimide resin adhesive varnish and drying, the face of the polyimide resin adhesive film to be coated with the varnish is coated with an aprotic polar solvent, coated with the varnish and dried. Cissing on the surface of the film is prevented by improving the compatibility of the polyimide resin adhesive film with the polyimide resin varnish to give the polyimide resin adhesive film excellent in surface properties.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive film used in the electronic and electric fields, and more particularly to an adhesive film using a polyimide resin as an adhesive.

[0002]

2. Description of the Related Art Polyimide resin adhesive films are used for insulation bonding in the fields of electronics and electric because of their high reliability. Adhesive films having a polyimide resin adhesive layer on one side of a polyimide resin film are used for protecting the circuit surface of a flexible circuit board used at high temperatures, and those having a polyimide resin adhesive on both sides are used in the semiconductor field, for example, lead. It is used for joining a frame and a semiconductor element, or joining a lead frame and a heat sink.

[0003] Such an adhesive film is produced by coating a polyimide resin varnish as an adhesive on one or both surfaces of a polyimide resin film, and scattering and drying the solvent by heating. Adhesive films produced as described above tend to have as thin an adhesive layer as possible because of their lightness and small size in the field of use.

[0004]

When a polyimide resin varnish is thinly coated, the familiarity between the polyimide resin film and the polyimide resin varnish is poor. Immediately after coating, repelling of the polyimide resin varnish occurs on the film surface, resulting in a good coated surface. There was a problem that it could not be obtained.

The present invention provides a polyimide resin adhesive film having a good coated surface by improving the familiarity between the polyimide resin film surface and the polyimide resin varnish.

[0006]

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve the above-mentioned problems, and as a result, by coating an aprotic polar solvent on the surface of the polyimide resin film in advance, it has been found that the polyimide resin varnish and It has been found that the familiarity is improved, repelling does not occur even when a polyimide resin varnish is coated, and a good coated surface is obtained, and the present invention has been completed.

That is, to produce a polyimide resin adhesive film obtained by coating and drying a heat-meltable polyimide resin adhesive varnish on one or both surfaces of a polyimide resin film, the varnish-coated surface of the polyimide resin film is A method for producing a polyimide resin adhesive film, comprising coating an aprotic polar solvent, coating the varnish, and drying.

The polyimide resin film used in the present invention does not melt by heat. As a commercially available example of such a polyimide resin film,
Upilex (manufactured by Ube Industries), Kapton (manufactured by DuPont), Apical (manufactured by Kanegafuchi Chemical Co., Ltd.) and the like can be mentioned. The thickness of the polyimide resin film is not particularly limited, but a film having a thickness of 10 to 125 μm is preferably used from the viewpoint of lightness and shortness.

As the polyimide resin adhesive used in the present invention, an adhesive which can be melted at a temperature of 400 ° C. or less is used. What is heat-meltable at 400 ° C or less is 400
As the material that can be thermally melted at a temperature of 400 ° C. or less, a material having an elastic modulus at a temperature of 400 ° C. or less of 100 Pa or more and 1 MPa or less is preferably used. If it is less than 100 Pa, sufficient mechanical properties cannot be obtained, and if it exceeds 1 MPa, sufficient adhesiveness to an adherend cannot be obtained.

In consideration of heat resistance, such a polyimide resin adhesive is polymerized by a known method with a diamine compound having an aromatic group and an acid dianhydride having an aromatic group. Furthermore, the viscosity is 0.1 g / ml or more, 2.0
g / ml or less, but preferably 0.3 g / ml or more and 1.0 g / ml or less. 0.1g / logarithmic viscosity
If the amount is less than 2.0 ml, the mechanical properties deteriorate. If the amount exceeds 2.0 g / ml, the elastic modulus increases, and sufficient heat melting property for obtaining adhesiveness cannot be obtained.

Specific examples of the diamine compound include p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 4,4'-diaminobenzophenone, and 3,3'-diaminobenzophenone. , 1,3-bis (3-aminophenoxy) benzene, bis4- (3-aminophenoxy)
Biphenyl, bis 4- (4-aminophenoxy) biphenyl, 2,2-bis (4- (3-aminophenoxy) phenyl) propane, 2,2-bis (4- (4-aminophenoxy) phenyl) propane and the like And used alone or as a mixture. Specific examples of the acid dianhydride include pyromellitic dianhydride, benzophenone tetracarboxylic dianhydride, oxyphthalic dianhydride, biphenyltetracarboxylic dianhydride and the like, and are used alone or as a mixture. You. However, the present invention is not limited to these examples, but has an aromatic group,
When the adhesive is finally used, any adhesive that exhibits heat fusibility at a temperature of 400 ° C. or less can be used. An aliphatic diamine or a silicone diamine can be used in combination as long as the heat resistance is not impaired.

In the present invention, the polyimide resin adhesive is preferably coated as a polyimide resin varnish. In general, coating is performed in the state of a polyamic acid varnish, which is a precursor of a polyimide resin. In this case, residual stress occurs due to shrinkage due to a condensation reaction during drying, and foaming occurs due to generated water. An aprotic polar solvent can be used as a solvent that can be used when preparing a polyimide resin varnish. For example, N-methyl-2-pyrrolidone, dimethylacetamide, dimethylformamide, dimethylsulfoxide, acetonitrile, nitrobenzene, benzonitrile, acetone, ethyl methyl ketone, glycol monoethyl ether, cyclohexanone, pyridine and the like. N-methyl-2-pyrrolidone, dimethylacetamide, dimethylformamide and the like can be mentioned. The thickness of the polyimide resin adhesive layer is 1 μm or more and 10 μm or less, preferably 3 μm or more and 7 μm or less. 1 μm
If it is less than 10 μm, sufficient adhesiveness cannot be obtained. If it exceeds 10 μm, the dimensional change of the adhesive film becomes large, and the reliability decreases.

In order to achieve the object of the present invention, it is necessary to coat the surface of the polyimide resin film with an aprotic polar solvent before coating the polyimide resin varnish. Among aprotic polar solvents,
Most preferably, the same solvent as that used for the polyimide resin varnish is most effective. As a coating method, a roll coater or a gravure coater for thin coating is preferable. After coating the solvent, it is preferable to dry the solvent so that the remaining amount of the solvent is 10 ppm or more and 10,000 ppm or less, preferably 100 ppm or more and 1000 ppm or less. If the content is less than 10 ppm, sufficient familiarity cannot be provided, and repelling of the polyimide resin varnish occurs. If it exceeds 10,000 ppm, the solvent coating layer becomes non-uniform, and the polyimide resin adhesive layer formed thereon also impairs the thickness uniformity. The drying method is not particularly limited, and a heating air method, an infrared ray, and a far infrared ray method are used.

Thereafter, one or both sides of the solvent-coated polyimide resin film are coated with a polyimide resin varnish, and the solvent is continuously dried and scattered in a drying step to solidify, thereby obtaining a polyimide resin having a polyimide adhesive layer. An adhesive film can be obtained. Hereinafter, the effects of the present invention will be described with reference to examples.

[0015]

【Example】

Example Both surfaces of a 50 μm-thick Kapton film (manufactured by DuPont) were coated with N-methyl-2-pyrrolidone by a roll coater and dried at 70 ° C. for 30 minutes. The residual solvent amount after drying was 400 ppm. A polyimide resin varnish PI-Ah (manufactured by Mitsui Toatsu Chemicals Co., Ltd.) using N-methyl-2-pyrrolidone as a solvent is coated on both sides of the Kapton film to a thickness of 5 μm after drying. Thereafter, drying was performed at a maximum drying temperature of 300 ° C. to obtain a polyimide resin adhesive film. Three 10 cm square test pieces were cut out at random from the obtained film, and the coated surface was visually inspected with a microscope of 30 times magnification. As a result, the coating defect due to the repelling of the polyimide resin varnish was zero.

Comparative Example A polyimide resin adhesive film was prepared in the same manner as in Example except that the coating with N-methyl-2-pyrrolidone was not carried out. Immediately after coating with the polyimide resin varnish, repelling occurred, and an average of 53 craters due to repelling were observed on the surface of the obtained polyimide resin adhesive film.

[0017]

According to the present invention, the surface of the polyimide resin film is coated with an aprotic polar solvent to improve the familiarity with the polyimide resin varnish, eliminate the repelling of the varnish on the film surface, and bond the polyimide resin with excellent surface properties. A film was obtained.

Claims (1)

[Claims] 1. A method for coating a polyimide resin adhesive varnish on one side or both sides of a polyimide resin film and drying the same, and producing a polyimide resin adhesive film obtained by drying the varnish-coated surface of the polyimide resin film. A method for producing a polyimide resin adhesive film, comprising coating an aprotic polar solvent, and then coating and drying the varnish.