JPH1180352A - Heat-resistant coating composition improved in its storage stability and polyimide membrane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition that can manifest high heat resistance and high strength by using an aromatic tetracarboxylic acid component and an aromatic diamine component to effect the polymerization so that the ratio of the organic residual groups of the derived polyamic acids becomes a specific value. SOLUTION: The objective composition is prepared by dissolving (A) an aromatic diamine as p-phenylenediamine in (B) an organic polar solvent and adding (C) an aromatic tetracarboxylic acid as (i) 3,3'4,4'-biphenyltetracarboxylic acid, its acidic ester or its acid dianhydride and (ii) 2,3,3',4'- biphenyltetracarboxylic acid, its acidic ester or its acid dianhydride to the resultant diamine solution so that the ratio of the residue of the component i becomes 85-98 mol.% in. the organic residual groups of the derived polyamic acid and the ratio of the residue of the component ii becomes 2-15 mol.% and polymerizing them at 0-70 deg.C. The polyimide membrane made from this composition can enhance the inhibition of its foam formation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polyamic acid solution which gives a polyimide having high heat resistance and high strength.
The present invention relates to a heat-resistant coating composition having improved storage stability and a polyimide film as a cured product thereof,
More specifically, starting materials are 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 2,3,3', 4'-biphenyltetracarboxylic dianhydride, derivatives thereof and paraphenylenediamine. The present invention relates to a heat-resistant coating composition having improved storage stability and a polyimide film.

[0002]

2. Description of the Related Art Conventional polyamic acid coating compositions starting from 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride and paraphenylenediamine have high heat resistance and high strength. Since it gives a polyimide film having excellent physical properties, it is widely used in the electronic field.

However, a polyamic acid coating composition (varnish) starting from 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride and paraphenylenediamine gradually becomes viscous during storage at room temperature. When a coating method (for example, spin coating or dip coating) is adopted in which the varnish viscosity increases and the varnish viscosity is determined, there is a problem that the reproducibility of the formed coating film thickness is lacking.
In addition, when a thick film (for example, a cured film having a thickness of 40 μm or more) is formed, bubbles may easily be generated, and the heat treatment operation may be complicated.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to improve the viscosity stability under storage at room temperature and the suppression of generation of bubbles without significantly lowering the physical properties such as heat resistance and strength of a formed film. To provide a coated polyamic acid coating composition.

[0005]

That is, the present invention provides:
3,3 ′, 4,4 ′ as aromatic tetracarboxylic acid component
-Biphenyltetracarboxylic acid, its acid ester or its dianhydride and 2,3,3 ', 4'-biphenyltetracarboxylic acid, its acid ester or its dianhydride and paraphenylenediamine as an aromatic diamine component A polyamic acid solution obtained by polymerization in an organic polar solvent using an aromatic diamine component
85-98 mol% of organic residues derived from 3 ′, 4,4′-biphenyltetracarboxylic acid, an acid ester or an acid dianhydride thereof, 2,3,3 ′, 4′-biphenyltetracarboxylic acid, The present invention relates to a heat-resistant coating composition having improved storage stability in which an organic residue derived from the acid ester or the acid dianhydride is in the range of 2 to 15 mol%.

The present invention also relates to a polyimide film obtained by applying the above-mentioned heat-resistant coating composition having improved storage stability to a substrate and drying by heating.

The heat-resistant coating composition having improved storage stability according to the present invention is prepared by, for example, mixing paraphenylenediamine and an organic polar solvent, and adding
3 ′, 4,4′-biphenyltetracarboxylic acid, its acid ester or its acid dianhydride and 2,3,3 ′, 4′-
Biphenyltetracarboxylic acid, an acid ester thereof, or an acid dianhydride thereof may be prepared by converting a 3,3 ′, 4,4′-biphenyltetracarboxylic acid residue in the organic residue of the derived polyamic acid (polyimide) to a ratio of 85-. 98 mol%, preferably 90-97 mol%, and the proportion of 2,3,3 ′, 4′-biphenyltetracarboxylic acid residue is 2-15 mol%, preferably 3-10 mol%. And 0
It can be obtained by polymerizing at -70 ° C.
At this time, water may be present in the reaction system to adjust the viscosity.
The heat-resistant coating composition of the present invention, which is a polyamic acid solution having improved storage stability, preferably has a viscosity (30 ° C.) of 5-1500 poise.

The heat-resistant coating composition having improved storage stability according to the present invention can be obtained by using a tetracarboxylic dianhydride component and a diamine component in substantially equimolar amounts. May be equimolar, or within the range of 1.02: 1-1: 0.90.

In the present invention, 3,3 ', 4,4'
-Biphenyltetracarboxylic acid or a derivative thereof and 2,
It is necessary to use 3,3 ', 4'-biphenyltetracarboxylic acid or a derivative thereof and paraphenylenediamine in a ratio within the above range, whereby the physical properties such as heat resistance and strength of the formed film are required. Without drastically lowering the viscosity, it is possible to improve the viscosity stability under storage at room temperature and the suppression of generation of bubbles.

In the present invention, other additional diamine components, such as 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfide, and 4,4 ', so long as the above-mentioned physical properties are not adversely affected. -Diaminodiphenylmethane and / or other acid components such as 3,
3 ', 4,4'-diphenylethertetracarboxylic dianhydride may be used.

Further, after mixing both components of the polyamic acid solution, a dicarboxylic anhydride such as phthalic anhydride and a substituted product thereof (such as 3-methyl or 4-methylphthalic acid) are used to seal the amine end of the polyimide precursor. Acid anhydride), hexahydrophthalic anhydride and substituted products thereof,
Preferably, phthalic anhydride, such as succinic anhydride and its substituted products, may be added.

The organic polar solvent used for producing the above polyamic acid includes N-methyl-2-pyrrolidone, N, N-
Examples include dimethylformamide, N, N-dimethylacetamide, N, N-diethylacetamide, dimethylsulfoxide, hexamethylphosphoramide, N-methylcaprolactam and the like. These organic solvents may be used alone or in combination of two or more.

The coating composition of the present invention is applied to a metal substrate such as copper, aluminum or an alloy or an inorganic substrate such as amorphous silicon, and a polyimide film finally obtained has a thickness of 0.1-0.1%. It can be applied to a thickness of 100 μm and dried by heating to a maximum heating temperature of 350 to 600 ° C. to form a polyimide film.

[0014]

The present invention will be described below in more detail with reference to examples and comparative examples.

Example 1 10.82 g of paraphenylenediamine (0.
1 mol), water 0.9 g (0.05 mol), N-methyl-
160.9 g of 2-pyrrolidone was added and dissolved at 50 ° C. with stirring and nitrogen flow. While maintaining this temperature, 1.47 g (0.005 mol) of 2,3,3 ', 4'-biphenyltetracarboxylic dianhydride was added to this solution, and then 3,3', 4,4'-biphenyltetracarboxylic acid was added. The carboxylic acid dianhydride was gradually added to prepare a 48 poise (30 ° C.) solution. At this point, the amount of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride used was 27.51 g (0.0
9351 mol). Acid component shortage 0.00149
The mol was added as 0.491 g of 3,3 ′, 4,4′-biphenyltetracarboxylic acid to finally obtain a 50.0 poise polyamic acid solution. Add this polyamic acid solution to 3
The viscosity (30 ° C.) after storage at 0 ° C. for each period (immediately after production, 2 months and 4 months later) was measured with an E-type viscometer. The physical properties of the polyimide film were measured. Table 1 shows the results.

Example 2 10.82 g of paraphenylenediamine (0.
1 mol), water 0.9 g (0.05 mol), N-methyl-
160.9 g of 2-pyrrolidone was added and dissolved at 50 ° C. with stirring and nitrogen flow. While maintaining this temperature, 2.94 g (0.010 mol) of 2,3,3 ', 4'-biphenyltetracarboxylic dianhydride was added to this solution, and then 3,3', 4,4'-biphenyltetracarboxylic acid was added. Carboxylic dianhydride was gradually added to prepare a 49 poise (30 ° C.) solution. At this point, the amount of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride used was 26.19 g (0.0
8900 mol). 0.0010 mol of the acid component deficiency was added as 0.33 g of 3,3 ', 4,4'-biphenyltetracarboxylic acid to finally obtain a 50.6 poise polyamic acid solution. The viscosity change of the polyamic acid solution after long-term storage (30 ° C.) and the physical properties of the polyimide film were measured. Table 1 shows the results.

Comparative Example 1 Without using 2,3,3 ', 4'-biphenyltetracarboxylic dianhydride, the amount of 3,3', 4,4'-biphenyltetracarboxylic dianhydride was reduced to 27. 2 from .51g
8.83 g (0.098 mol), the intermediate viscosity from 48 poise to 48.5 poise (30 ° C.), the acid component shortage from 0.00149 mol to 0.0020 mol,
Example 1 except that the amount of 3 ', 4,4'-biphenyltetracarboxylic acid was changed from 0.491 g to 0.660 g.
In the same manner as described above, a 51.5 poise polyamic acid solution was obtained. Long-term storage of this polyamic acid solution (30 ° C)
The subsequent change in viscosity and the physical properties of the polyimide film were measured. Table 1 shows the results.

Measurement of Various Physical Properties Coating Physical Properties The polyamic acid solution obtained in each example was applied to a glass substrate so that the thickness of a polyimide film finally obtained was 25 μm, and was applied at 80 ° C. for 30 minutes and at 120 ° C. for 60 minutes. Minutes, 1
30 minutes at 0 ° C, 30 minutes at 250 ° C, 30 minutes at 330 ° C,
Then, heat treatment was performed at 450 ° C. for 10 minutes to obtain a polyimide film. The physical properties of this polyimide film were evaluated by the following measurement methods. Elastic modulus: ASTM D-882 Elongation: ASTM D-882 Breaking strength: ASTM D-882 5% weight loss temperature: In air at a heating rate of 10 ° C./min.
Measured by TGA.

Further, the polyamic acid solution obtained in each example was applied to an aluminum substrate having a thickness of 1 mm so that the polyimide film finally obtained had a thickness of 50 μm.
30 minutes at 0 ° C, 60 minutes at 120 ° C, 30 minutes at 170 ° C,
30 minutes at 250 ° C, 30 minutes at 330 ° C, then 450 ° C
For 10 minutes to obtain a polyimide film. It was visually observed whether or not bubbles were generated in the polyimide film.

[0020]

[Table 1]

[0021]

The heat-resistant coating composition of the present invention, which is a polyamic acid solution, can be used under room temperature storage of a varnish without significantly lowering the physical properties such as heat resistance and strength of the polyimide film to be formed. It is possible to improve viscosity stability and suppression of generation of bubbles in the polyimide film.

The polyimide film of the present invention has a structure of 3, 3 ',
4,4′-biphenyltetracarboxylic dianhydride-paraphenylenediamine-based polyimide originally has heat resistance,
It is possible to improve the suppression of generation of bubbles without significantly reducing physical properties such as strength.

Claims (2)

[Claims] 1. An aromatic tetracarboxylic acid component comprising 3,3
3 ′, 4,4′-biphenyltetracarboxylic acid, its acid ester or its acid dianhydride and 2,3,3 ′, 4′-
A polyamic acid solution obtained by polymerization in an organic polar solvent using biphenyltetracarboxylic acid, an acid ester or an acid dianhydride thereof, and an aromatic diamine component such as paraphenylenediamine as an aromatic diamine component. 2,3 ', 4,4'-biphenyltetracarboxylic acid, 85-98 mol% of organic residues derived from acid ester or acid dianhydride thereof, 2,3,3', 4'-biphenyltetracarboxylic acid A heat-resistant coating composition having improved storage stability, wherein an organic residue derived from the acid ester or the acid dianhydride is in the range of 2 to 15 mol%. 2. A polyimide film obtained by applying the heat-resistant coating composition having improved storage stability according to claim 1 to a substrate and drying by heating.