JPH04318025A - Polyamic acid resin composition - Google Patents

Abstract

PURPOSE:To provide a polyamic acid resin composition containing a specific carboxylic dianhydride component and an aromatic diamine in a constant molar ratio as essential components, and having excellent heat resistance, excellent adhesivity to metal foils and further a thermal expansion coefficient near to those of the metal foils. CONSTITUTION:The objective composition comprises (A) a tetracarboxylic dianhydride containing (i) 3,3',4,4'-biphenyltetracarboxylic dianhydride as an essential component and 0-50mol% of (ii) 3,3',4,4'-benzophenone tetracarboxylic dianhydride and/or (iii) bis(3,4-dicarboxyphenyl)ether dianhydride and (B) an aromatic diamine comprising (iv) an aromatic diamine of the formula (R1, R2 are H, 1-3C alkyl) such as p-phenylene diamine and (v) 1,3-bis(3-aminophenoxy) benzene in a (iv)/(v) ratio of 70:30 to 90:10, the molar ratio of the acid component to the diamine component being 0.9-1.1, and gives flexible substrates having excellent adhesivity, dimensional stability and heat resistance.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a polyamic acid resin composition particularly suitable for flexible printed circuit boards, and more particularly, it relates to a polyamic acid resin composition that is composed of two or three aromatic tetracarboxylic dianhydrides and two or more aromatic tetracarboxylic dianhydrides. The present invention relates to a polyamic acid resin composition comprising more aromatic diamine components.

0002

BACKGROUND OF THE INVENTION Polyimide is widely known as a highly heat-resistant polymer, but has a drawback in moldability due to its rigid molecular skeleton. Furthermore, with the recent development of the electronic and electrical industries, flexible printed circuit boards, which are lightweight and can be mounted three-dimensionally, have been widely used as a mounting method for communication and consumer equipment. Polyimide films are currently widely used in flexible printed circuit boards. In this case, the performance required of the polyimide film is heat resistance,
These include adhesive strength with metal foil, matching thermal expansion coefficient with metal foil, and electrical insulation. Various polyimides have been developed so far, but those with excellent heat resistance have poor adhesive strength with metals, while those with excellent adhesive strength have a larger coefficient of thermal expansion than metal foils, making it difficult to roll them onto substrates. There were drawbacks such as:

0003

[Problems to be Solved by the Invention] The present invention was obtained as a result of research aimed at obtaining a polyimide resin that has excellent heat resistance and adhesive strength with metal foil, and also has a coefficient of thermal expansion close to that of metal foil. It is something.

0004

[Means for Solving the Problems] The present invention provides 3, 3', 4
, 4'-biphenyltetracarboxylic dianhydride (hereinafter referred to as B
(abbreviated as PDA) is an essential component, and 3,3',4,4'-
Benzophenone tetracarboxylic dianhydride (hereinafter referred to as BTD)
An acid dianhydride component containing 0 to 50 mol% of bis(3,4-dicarboxyphenyl)ether dianhydride (hereinafter abbreviated as ODPA); and general formula (I)

[
0005

[Chemical 2]

The ratio of one or more aromatic diamines represented by: and 1,3-bis(3-aminophenoxy)benzene (hereinafter abbreviated as APB) is 70:30 to 90:1.
The present invention relates to a polyamic acid resin composition comprising an aromatic diamine having a concentration of 0.0 and a molar ratio of an acid component to a diamine component of 0.9 to 1.1.

[0007]

[Operation] The polyamic acid solution used in the present invention is prepared by combining an aromatic carboxylic dianhydride component in a solvent such as N-methyl-2-pyrrolidone (hereinafter abbreviated as NMP), dimethylacetamide, dimethylformamide, or cresol. It can be obtained by stirring the aromatic diamine component. The molar ratio of the aromatic carboxylic dianhydride component and the aromatic diamine component is preferably 0.90 to 1.10,
More preferably, it is 0.97 to 0.99. When the molar ratio of the acid component and the amine component is out of the above-mentioned range, the molecular weight of the polyimide produced becomes small and the physical properties of the product deteriorate. Particularly when considering heat resistance, it is preferable to react with an excess of the diamine component.

[0008] Acid components used in the polyamic acid of the present invention include BPDA, BTDA, and ODPA. The molar content of BPDA in the acid component is preferably 50 mol% or more, particularly preferably 70 to 80 mol%. The molar ratio of BTDA and ODPA is 100:0 to 0:10
Can be used arbitrarily within the range of 0, but 90:10
~50:50 is preferred, particularly preferably 80:20~
It is 70:30. A resin composition synthesized using BPDA as an essential component can further improve adhesiveness by making it a copolymer with BTDA and ODPA.

Examples of the aromatic diamine represented by the general formula (I) include p-phenylenediamine (hereinafter abbreviated as PPD), m-phenylenediamine (hereinafter abbreviated as MPD), 2
,4-tolylenediamine (hereinafter abbreviated as 2,4-TDA)
, 1,4-dimethyl-2,5-diaminobenzene (hereinafter abbreviated as 25DPX). The ratio of one or more of these to APB is preferably 70:30 to 95:5, particularly preferably 75:25 to 90:10. A
By adding PB in this range, the adhesive strength can be improved. If the amount of APB added is 30 mol %, the adhesive strength will improve, but the heat resistance will decrease and the coefficient of thermal expansion will also increase. Among the aromatic diamines represented by the general formula (I), the amount of p-phenylenediamine added is preferably 20 to 70 mol%, particularly preferably 30 to 60 mol%, based on the total amount of diamine components. As the amount of PPD added increases, the heat resistance of the polyimide film improves, and the value of the coefficient of thermal expansion decreases. On the other hand, the adhesive strength decreases.

The polyamic acid resin composition of the present invention can be applied to a metal foil such as a copper foil or an aluminum foil, and a printed circuit board can be obtained by drying and curing the composition. It is also possible to impregnate a substrate such as glass cloth to prepare a prepreg. The drying temperature of the resin composition applied to these base materials is usually 80 to 380°C, and a printed circuit board can be obtained by heating in this temperature range for 10 to 180 minutes.

The resin composition of the present invention can also be used for adhering metals to plastics such as polyimide, and has excellent adhesion between metals and between plastics. In addition, due to its excellent heat resistance, it is also possible to obtain a double-sided board by laminating the polyimide sides of two-layer flexible printed circuit boards made of polyimide and metal foil without an adhesive layer. . Furthermore, a double-sided flexible printed circuit board can also be obtained by bonding copper foils together. It can also be used as an adhesive for highly heat-resistant film cover coats.

0012

【Example】

(Example 1) PPD3 was used as a four-necked glass cohediamine component equipped with a stirrer, a thermometer, a nitrogen inlet tube, and a reflux condenser tube.
．． 24g (0.03 mol), 25DPX8.17g (0
．． 06 mol) and 2.94 g (0.01 mol) of APB were added, and 100 g of NMP was added, followed by sufficient stirring at room temperature under a nitrogen stream to dissolve the diamine component. Then, BPDA
20.18g (0.07mol), BTDA9.47g (
0.03 mol) was gradually added, 75 g of NMP was added,
The mixture was stirred at room temperature for 4 hours. 75 g of ethanol was added thereto, and the mixture was further stirred for 1 hour. The reduced viscosity of the obtained solution (measured by dissolving 0.5 g of resin in 100 ml of NMP in a constant temperature bath at 30°C) was 0.5, and the resin content was 15% by weight.
Met. This resin solution was applied onto a 35 μm thick copper foil so that the thickness after drying would be 25 μm, and dried at 100° C. for 1 hour and at 350° C. for 1 hour to obtain a flexible substrate.

(Example 2) As a diamine component, PPD
5.41g (0.05 mol), MPD 4.33g (0.
04 mol), APB 2.92 g (0.01 mol), BPDA 20.18 g (0.07 mol), O
A flexible substrate was obtained using the same apparatus and method as in Example 1 using 9.12 g (0.03 mol) of DPA.

(Example 3) As a diamine component, PPD
7.75g (0.07mol), 2,4-TDA2.44
g (0.02 mol), APB 2.92 g (0.01 mol), acid components: BPDA 20.18 g (0.07 mol), BTDA 6.32 g (0.02 mol), ODPA
A flexible substrate was obtained using the same apparatus and method as in Example 1 using 3.04 g (0.01 mol).

(Comparative Example 1) As a diamine component, 25D
PX6.81g (0.05mol), APB14.62g
(0.05 mol), BPDA20.18 as an acid component
A flexible substrate was obtained using the same apparatus and method as in Example 1, using 9.47 g (0.03 mol) of BTDA and 9.47 g (0.07 mol) of BTDA.

(Comparative Example 2) As the diamine component, PPD
7.57g (0.07mol), 24TDA3.67g (
0.03 mol), BTDA22.56g as acid component
A flexible substrate was obtained using the same apparatus and method as in Example 1 using ODPA (0.07 mol) and 9.12 g (0.03 mol) of ODPA.

Above, Examples 1, 2, 3 and Comparative Examples 1, 2
Table 1 shows the results of evaluating the flexible substrate and its film obtained in . The flexible substrate using the resin composition of the example showed excellent values with well-balanced peel strength and coefficient of thermal expansion compared to the comparative example.

[0018]

[Table 1]

[0019]

[Effects of the Invention] The polyimide resin obtained by the present invention has excellent heat resistance and adhesion to metal foil, and has a coefficient of thermal expansion close to that of metal foil. By using this, a flexible substrate can be obtained that has superior adhesiveness, dimensional stability, and heat resistance compared to conventional polyimide resins. It is also useful as a composition for impregnating prepregs and as an adhesive for film cover coats.

Claims (2)

[Claims] Claim 1: 3,3',4,4'-biphenyltetracarboxylic dianhydride as an essential component;
A carboxylic dianhydride component containing 0 to 50 mol% of 4'-benzophenone tetracarboxylic dianhydride and/or bis(3,4-dicarboxyphenyl)ether dianhydride, and general formula (I) [Formula 1] one or more aromatic diamines represented by 1,
The ratio to 3-bis(3-aminophenoxy)benzene is 7.
consisting of an aromatic diamine having a ratio of 0:30 to 90:10,
A polyamic acid resin composition in which the molar ratio of acid component to diamine component is 0.9 to 1.1. 2. The polyamic acid resin composition according to claim 1, wherein the content of p-phenylenediamine in the aromatic diamine component represented by general formula (I) is 20 to 70 mol% of the total amount of the aromatic diamine component. thing.