JPH0790243A - Polyimide film adhesive - Google Patents

Abstract

PURPOSE:To provide a polyimide film adhesive containing a specific polyimide resin and a specific rubber having high molecular weight, exhibiting excellent heat-resistance, adhesion and flexibility and suitable for circuit board, etc. CONSTITUTION:This polyimide film adhesive contains (A) a polyimide resin of the formula I {R<1> is tetravalent organic acid residue; >=50mol% of the total acid component constituting the group R<1> is biphenyl ether tetracarboxylic acid of the formula II; R<2> is bivalent diamine residue; 50-99mol% of the total diamine component constituting the group R<2> is diamine compound of the formula III [X is CH2, O, C(CH3)2, SO2 or C(CF3)2] and 50-1mol% is diaminosiloxane of the formula IV (R'' and R' are bivalent organic group; R<5> to R<8> are 1-6C hydrocarbon group; (n) is 0-12)} and (B) preferably 5-40wt.% (based on the component A) of a high-molecular weight rubber having a weight-average molecular weight of >=10,000.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyimide film adhesive suitable for circuit boards and the like.

[0002]

2. Description of the Related Art Conventionally, polyester or epoxy type adhesives have been used as circuit board film adhesives. However, these films were not entirely satisfactory. That is, the polyester film adhesive is
It has poor heat resistance and cannot be said to be suitable as an adhesive for circuit boards. Epoxy film adhesives also have the drawback of poor flexibility and low dielectric properties. Although polyimide film adhesives that have improved these drawbacks have been attempted, depending on the composition of the polyimide precursor, the adhesive force between the generated polyimide film and the metal foil is insufficient, resulting in a peeling phenomenon during circuit pattern formation. There was a flaw that caused it.

[0003]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks, and is excellent in heat resistance, adhesion and flexibility, and has the drawbacks of conventional productivity and economy. It is an object to provide a solved polyimide film adhesive.

[0004]

Means for Solving the Problems As a result of intensive studies to achieve the above-mentioned object, the present inventor has studied polymers having various chemical structures, and by using a polyimide resin composition described later, The inventors have found that the above objects can be achieved and completed the present invention.

That is, the present invention provides (A) a polyimide resin represented by the following general formula:

[0006]

[Chemical 5] (A) R ¹ in the general formula of the polyimide resin is 4
Showing a divalent organic acid residue, 50 mol% or more of all the acid components constituting R ¹ is a biphenyl ether tetracarboxylic acid represented by the following general formula,

[0007]

[Chemical 6] (B) R ² in the general formula of the polyimide resin is 2
A diamine residue having a valence of 50 to 99 mol% of all the diamine components constituting (b-1) R ² is a diamine compound represented by the following general formula:

[0008]

[Chemical 7] (However, in the formula, X is —CH ₂ —, —O—, —C (CH ₃ ) _{2
-, - SO 2 -, -} C (CF 3) 2 - represents a) (b-2)
50 to 1 mol% of all diamine components constituting R ²
Is a diaminosiloxane represented by the following general formula:

[0009]

[Chemical 8] (However, in the formula, R ³ and R ⁴ are divalent organic groups, R ^{5 to} R 4
⁸ represents a hydrocarbon having 1 to 6 carbon atoms, n represents a positive integer of 0 or 12 or less), and (B) a high-molecular-weight rubber having a weight average molecular weight of 10,000 or more. It is an adhesive.

The present invention will be described in detail below.

The (A) polyimide resin used in the present invention has the above-mentioned general formula 5, and has (a) an acid component and (b)
It is obtained by reacting with a diamine component.

As the (a) acid component used in the polyimide resin, the biphenyl ether tetracarboxylic acid component represented by the above general formula 6 can be used. Specific examples of the biphenyl ether tetracarboxylic acid component include 3,4,3 ′, 4′-biphenyl ether tetracarboxylic acid, 2,3,3 ′, 4′-biphenyl ether tetracarboxylic acid, or acids thereof. An anhydride, a lower alkyl ester, etc. are mentioned, These can be used individually or in mixture. It is desirable to use the biphenyl ether tetracarboxylic acid component in an amount of 50 mol% or more of the total acid component. If it is less than 50 mol%, the acid resistance is poor and it is not preferable.

Acid components other than biphenyl ether tetracarboxylic acid include, for example, pyromellitic acid, 3,3'4,
4'-biphenyl tetracarboxylic acid, 2,3,3 ', 4'-biphenyl tetracarboxylic acid, 3,3', 4,4'-benzophenone tetracarboxylic acid, 2,3,3 ', 4'-benzophenone tetra Carboxylic acid, 1,4,5,8-naphthalene tetracarboxylic acid, 2,3,6,7-naphthalene tetracarboxylic acid, 1,2,5,6-naphthalene tetracarboxylic acid, 3,4,9,10- Tetracarboxyphenylene, 3,3 ', 4,4'-biphenylmethanetetracarboxylic acid, 2,2-bis (3,4-dicarboxyphenyl) propane, 2,2-bis (3,4-dicarboxyphenyl) Anhydrous or lower alkyl such as hexafluoropropane, 3,3 ', 4,4'-diphenylsulfone tetracarboxylic acid, 2,2-bis ([4- (3,4-dicarboxyphenoxy) phenyl] hexafluoropropane Esters and the like can be mentioned, and these can be used alone or as a mixture to prepare the aforementioned biphenyl ether tetracarbohydrate. It can be used in combination with acid.

As the (b) diamine component used in the polyimide resin, the (b-1) diamine compound and the (b-2) diaminosiloxane are used together in a fixed ratio.

Specific examples of the (b-1) diamine compound include 2,2-bis [4- (4-aminophenoxy) phenyl] propane and 2,2-bis [4- (4-aminophenoxy). ) Phenyl] hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl] ether, 2,2-
Bis [4- (4-aminophenoxy) phenyl] methane, 2,
2-bis [4- (4-aminophenoxy) phenyl] sulfone and the like can be mentioned, and these can be used alone or in combination. This diamine compound and the below-mentioned diaminosiloxane are used together in a fixed ratio.

As the (b-2) diaminosiloxane, one having the above general formula 8 is used. Specific examples of the compound include bis (γ-aminopropyl) tetramethyldisiloxane, bis (4-aminobutyl) tetramethyldisiloxane, bis (γ-aminopropyl) tetraphenyldisiloxane, 1,4-bis ( (γ-aminopropyldimethylsilyl) benzene and the like can be used, and these can be used alone or in combination.

As the diamine component, it is important to use the above-mentioned (b-1) diamine compound and (b-2) diaminosiloxane together in a fixed ratio. The mixing ratio of these is such that (b-1) diamine compound is based on all diamine components.
50-99 mol%, 50% of (b-2) diaminosiloxane
It is desirable to mix them in a proportion of ~ 1 mol%. When the content of the (b-1) diamine compound is less than 50 mol%, the chemical resistance is lowered, and the (b-2) diaminosiloxane is less than 1 mol%.
If it is less than mol%, the compatibility with the high molecular weight rubber component is poor,
Adhesion to an inorganic film (silicon dioxide film or silicon nitride film) of a semiconductor device or the like is lowered, which is not preferable.

The polyimide resin obtained by reacting the above-mentioned acid component and diamine component may contain the acid component and diamine component in a block or random manner. The polyimide resin, as a precursor solution of 0.5 g of polyamic acid resin / 10 ml of N-methyl-2-pyrrolidone, preferably has a logarithmic viscosity at 30 ° C. in the range of 0.2 to 4.0, more preferably. 0.3-2.0
Is the range. The polyamic acid resin is obtained by subjecting an acid component and a diamine component of approximately equimolar amounts to an addition polymerization reaction in an organic solvent at a reaction temperature of 30 ° C. or lower, preferably 20 ° C. or lower for 3 to 12 hours. Examples of the organic solvent in this polymerization reaction include N, N'-dimethyl sulfoxide, N,
N'-dimethylformamide, N, N'-diethylformamide, N, N'-dimethylacetamide, N, N '
-Diethylacetamide, N-methyl-2-pyrrolidone,
Hexamethylene phosphoamide and the like can be used, and these can be used alone or in combination.

The (B) high molecular weight rubber having a weight average molecular weight of 10,000 or more, which is another important component used in the present invention, includes, for example, acrylic rubber, acrylonitrile-butadiene rubber, modified acrylonitrile-butadiene rubber, polyvinyl butyral and the like. Polymerizable rubbers may be used, and these may be used alone or in admixture of two or more.
When the weight average molecular weight of the high molecular weight rubber is less than 10,000, sufficient flexibility cannot be obtained and wetting is poor, which is not preferable. The blending ratio of high molecular weight rubber having a weight average molecular weight of 10,000 or more is
It is desirable to mix the polyimide resin in the range of 5 to 40% by weight. If the proportion is less than 5% by weight, the adhesion to various substrates is not sufficient, and if it exceeds 40% by weight, the polyimide resin and the rubber component are likely to be separated from each other, which is not preferable. As a method of mixing the high molecular weight rubber with the polyamic acid resin described above, a solution in which a rubber component is previously dissolved in an appropriate solvent can be mixed with the polyamic acid resin solution and stirred to be manufactured.

The operation of coating the release paper or film with the polyamic acid resin solution is preferably carried out by casting, and specifically, the following method is used. A coating film layer having a uniform thickness (generally adjusted to 10 to 300 μm) is formed on a release paper or film by discharging a polyamic acid resin solution through a film-forming slit. As other coating means,
Well-known means such as a roll coater, a knife coater, a comma coater, a doctor blade and a flow coater can be used. The polyamite coating layer thus formed is heated to perform solvent removal and dehydration cyclization. In general,
Heat to 100-250 ° C, preferably 200-250 ° C. In this way, the polyimide film is formed on the release paper or film.

The method for adhering the polyimide film adhesive to the metal foil or the like is preferably a heating / pressurizing method. Specifically, the following method is used. The heating / pressurizing adhesion is generally performed with the sheet spread. The polyimide film adhesive is placed directly on the metal foil or plate, and then heated and pressed to fuse the polyimide film. The temperature at this time is 150 to 250 ° C, preferably 200 to 250 ° C.
250 ° C is suitable. Further, the metal foil or plate may be multilayered with a polyimide film adhesive interposed therebetween.

The polyimide film adhesive thus obtained is used for flexible circuit boards, hybrid IC boards, LS
It can be used for I mounting substrates, various printed wiring boards, and the like, and is particularly suitable for fields requiring flexibility.

[0023]

The polyimide film adhesive of the present invention, by using a specific acid component and a specific diamine component, imparts low chemical resistance to hydrofluoric acid and the like, and also imparts adhesiveness and flexibility. It is a thing. In addition, the excellent heat resistance, electric insulation, etc., which are the characteristics of conventional polyimide, are retained as they are.

[0024]

EXAMPLES The present invention will now be described with reference to examples, but the present invention is not limited to these examples.

Example 1 A flask equipped with a stirrer, a condenser and a nitrogen inlet tube was charged with
2,2-bis [4- (4-aminophenoxy) phenyl] propane 36.9g (0.09mol) and bis (γ-aminopropyl)
2.49 g (0.01 mol) of tetramethyldisiloxane and N-
Methyl-2-pyrrolidone (268.3 g) was added, and 30.38 g (0.098 mol) of 3,3 ′, 4,4′-biphenyl ether tetracarboxylic dianhydride was added at room temperature under a nitrogen atmosphere while paying attention to the rise of the solution temperature. The mixture was added in portions and stirred at room temperature for 12 hours to obtain a polyamic acid resin solution. 100 parts by weight of this polyamic acid resin solution (80% solution of N-methyl-2-pyrrolidone)
6 parts by weight of a 70% solution of methyl ethyl ketone in Nipol 1072 (manufactured by Nippon Zeon Co., Ltd., trade name, molecular weight 500,000) was added uniformly to the whole to prepare a polyamic acid resin.
Then, a polyamic acid resin was cast and coated on the release film to uniformly coat it to a thickness of 35 μm and dried by heating at 180 ° C. to produce a polyimide film adhesive.

Example 2 In a flask equipped with a stirrer, a cooler and a nitrogen introducing tube,
2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane 46.6 g (0.09 mol) and bis (γ-aminopropyl) tetraphenyldisiloxane 4.97 g (
0.01 mol) and 268.3 g of N-methyl-2-pyrrolidone were added, and 15.50 g (0.050 mol of 0.053 mol of 3,3 ', 4,4'-biphenyl ether tetracarboxylic acid dianhydride under nitrogen atmosphere at room temperature.
) And pyromellitic dianhydride (10.46 g (0.048 mol)) are added in portions while paying attention to the increase in solution temperature, and the mixture is added at room temperature to 10
After stirring for a time, a polyamic acid resin solution was obtained. To 100 parts by weight of this polyamic acid resin solution (80% solution of N-methyl-2-pyrrolidone), 70% solution of methyl ethyl ketone in JS
RN6328 (Nippon Synthetic Rubber Co., Ltd., trade name, molecular weight 30
10,000 parts by weight was added and the whole was uniformly mixed to produce a polyamic acid resin. Then, a polyamic acid resin was cast and coated on the release film to uniformly coat it to a thickness of 35 μm and dried by heating at 180 ° C. to produce a polyimide film adhesive. Comparative Example A commercially available acrylic rubber film was obtained as a comparative example.

The film adhesives obtained in Examples 1 and 2 and Comparative Example were tested for soldering resistance and adhesion. The results are shown in Table 1. The characteristics of the present invention are excellent,
The effect of the present invention could be confirmed.

[0028]

[Table 1] When film adhesive and copper foil are polyimide film adhesive, press bond at 5-10kg / cm at 290 ° C for 10 minutes, and acrylic rubber film adhesive at room temperature 0.7 kg / cm. It was * 1: Measured according to JIS-C-6481. * 2: Measured according to ASTM-D-1875.

[0029]

As is clear from the above description and Table 1, the polyimide film adhesive of the present invention is excellent in heat resistance, adhesiveness and flexibility, and has the heat resistance and insulation of conventional polyimide resins. It also has good property balance, and has flexible circuit board, hybrid IC board, L
It can be used for SI mounting substrates, various printed wiring boards, and the like, and is particularly suitable for fields requiring flexibility.

Claims (1)

[Claims] 1. A polyimide resin represented by the following general formula (A), wherein: (A) R ¹ in the general formula of the polyimide resin is 4
A divalent organic acid residue is shown, and 50 mol% or more of all the acid components constituting R ¹ is a biphenyl ether tetracarboxylic acid represented by the following general formula: (B) R ² in the general formula of the polyimide resin is 2
A diamine residue having a valence of 50 to 99 mol% of all the diamine components constituting (b-1) R ² is a diamine compound represented by the following general formula: (However, in the formula, X is —CH ₂ —, —O—, —C (CH ₃ ) _{2
-, - SO 2 -, -} C (CF 3) 2 - represents a) (b-2)
50 to 1 mol% of all diamine components constituting R ²
Is a diaminosiloxane represented by the following general formula: (However, in the formula, R ³ and R ⁴ are divalent organic groups, R ^{5 to} R 4
⁸ represents a hydrocarbon having 1 to 6 carbon atoms, n represents 0 or a positive integer of 12 or less), and (B) a high molecular weight rubber having a weight average molecular weight of 10,000 or more. Polyimide film adhesive.