JPH04331232A - Polyamic acid resin composition for flexible printed board - Google Patents

Abstract

PURPOSE:To obtain the title composition which can give a flexible board excellent in adhesiveness, dimensional stability and heat resistance by reacting one, two or three specified aromatic tetracarboxylic acid dianhydride with three specified aromatic diamines. CONSTITUTION:A polyamic acid resin composition is obtained by reacting a carboxylic acid dianhydride component (A) comprising 3,3',4,4'- biphenyltetracarboxylic dianhydride as an essential component and 0-50mol% 3,3',4,4'-benzophenonetetracarboxylic dianhydride and/or bis(3,4-dicarboxyphenyl) ether dianhydride with an atomatic diamine component (B) comprising an aromatic diamine of the formula (wherein R1 and R2 are each H, 1-3C alkyl or alkoxy), p-phenylenediamine and 1,3-bis(3-aminophenoxy)benzene in the molar ratio of a component A to component B of 0.9-1.1. A flexible board made of this composition excels in adhesiveness, dimensional stability and heat resistance.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a polyimide or polyamic acid resin composition for flexible printed circuit boards. The present invention relates to a polyamic acid resin composition for flexible printed circuit boards comprising a group diamine component.

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 adhesion to metals, while those with excellent adhesion have a higher coefficient of thermal expansion than metal foils and tend to curl on the substrate. There were drawbacks such as the occurrence of

0003

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

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)
A carboxylic dianhydride component containing 0 to 50 mol% of bis(3,4-dicarboxyphenyl)ether dianhydride (hereinafter abbreviated as ODPA); and general formula (I)

[0005]

[Case 2]

Aromatic diamines represented by: p-phenylenediamine (hereinafter abbreviated as PPD) and 1,3-bis(
3-aminophenoxy)benzene (hereinafter abbreviated as APB)
The present invention relates to a polyamic acid resin composition in which an aromatic diamine component consisting of the following is reacted at a molar ratio of acid component to diamine component of 0.9 to 1.1.

[0007]

[Operation] The polyamic acid solution used in the present invention is prepared by preparing an aromatic tetracarboxylic dianhydride component in a solvent such as N-methyl-2-pyrrolidone (hereinafter abbreviated as NMP), dimethylacetamide, dimethylformamide, or cresol. and an aromatic diamine component.

The molar ratio of the aromatic tetracarboxylic dianhydride component to the aromatic diamine component is preferably 0.90 to 1.10, more preferably 0.97 to 0.99. When the molar ratio of the acid component and the amine component is out of the above range,
The molecular weight of the polyimide produced decreases, and the physical properties of the product deteriorate. Especially when considering heat resistance, it is preferable to react with an excess of the diamine component.

[0009] Acid components used in the polyimide 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%.

[0010] The molar ratio of BTDA and ODPA is 100:
It can be used arbitrarily within the range of 0 to 0:100, but preferably 90:10 to 50:50, particularly preferably 80:20 to 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.

Aromatic diamines represented by general formula (I) include 4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethoxy-4, 4'-diaminobiphenyl, 3,3'-
Examples include dihydroxy-4,4'-diaminobiphenyl. The proportion of the component represented by general formula (I) in the wholly aromatic diamine is preferably 10 to 60 mol%, particularly 30 to 60 mol%.
~50 mol% is preferred. If the proportion of the aromatic diamine represented by the general formula (I) is 10 mol % or less, the value of the thermal expansion coefficient becomes large. On the other hand, at 60 mol% or more,
It becomes brittle when made into a film.

Similarly, the proportion of PPD is preferably 20 to 80 mol%, particularly preferably 30 to 70 mol%. If it is less than 20 mol %, the value of the coefficient of thermal expansion will become large, and on the contrary, if it is more than 80 mol %, the adhesive force with the metal foil will decrease.

[0013] The proportion of APB is preferably 5 to 30 mol%, particularly preferably 5 to 20 mol%. By adding APB, the adhesive strength with metal foil can be improved. However, if 30 mol% or more is added, the value of the thermal expansion coefficient becomes large.

[0014] The polyimide or polyamic acid resin composition of the present invention can be applied to a metal foil such as copper foil or aluminum foil, and a printed circuit board can be obtained by drying and curing it. 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 substrates is usually 80 to 380°C, and within this temperature range 10
A printed circuit board can be obtained by heating for ~180 minutes.

The resin composition of the present invention can also be used for adhering metals to plastics such as polyimide, and also has excellent adhesion between metals and between plastics. In addition, due to its excellent heat resistance, a double-sided board can be obtained by bonding 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.

[0017]

【Example】

(Example 1) A 4-necked flask equipped with a stirrer, a thermometer, a nitrogen inlet tube, and a reflux condenser.As a hediamine component, 3,3
'-dihydroxy-4,4'-diaminobiphenyl8.
65g (0.04mol), PPD4.33g (0.04mol)
mol), add 5.88 g (0.02 mol) of APB, and add N
100 g of MP was added and thoroughly stirred at room temperature under a nitrogen stream to dissolve the diamine component.

Next, BPDA20.18g (0.07
9.47 g (0.03 mol) of BTDA were gradually added thereto, 75 g of NMP was added, and 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. Reduced viscosity of the obtained solution (0.5 g of resin in 100 ml
(dissolved in NMP and measured in a constant temperature bath at 30°C) is 0.5
Met.

This resin solution was applied onto a 35 μm thick copper foil so that the thickness after drying would be 25 μm, and heated at 100° C./1.
The substrate was dried at 350° C. for 1 hour to obtain a flexible substrate.

(Example 2) As the diamine component, 3,3
'-Dimethoxy-4,4'-diaminobiphenyl9.7
7g (0.04 mol), PPD 4.33 g (0.04 mol), APB 5.88 g (0.02 mol), BPDA 20.18 g (0.07 mol), ODPA as acid components
A flexible substrate was obtained using the same apparatus and method as in Example 1 using 9.12 g (0.03 mol).

(Comparative Example 1) As the diamine component, 3,3
'-dihydroxy-4,4'-diaminobiphenyl 10
．． 81g (0.05 mol), APB14.62g (0.05 mol).
05 mol), 20.18 g of BPDA (0.05 mol) 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.

(Comparative Example 2) As the diamine component, 3,3
'-dihydroxy-4,4'-diaminobiphenyl8.
65g (0.04mol), PPD4.33g (0.04mol)
mol), APB 5.88 g (0.02 mol), acid component: BTDA 22.56 g (0.07 mol), ODP
A flexible substrate was obtained using the same apparatus and method as in Example 1 using 9.12 g (0.03 mol) of A.

Table 1 shows the results of evaluating the flexible substrates and films thereof obtained in Examples 1 and 2 and Comparative Examples 1 and 2.

[0024]

[Table 1]

[0025] The flexible substrate using the resin composition of the example exhibited excellent, well-balanced peel strength and coefficient of thermal expansion compared to the comparative example.

[0026]

[Effects of the Invention] Flexible substrates made using the polyamic acid resin composition obtained by the present invention have superior adhesiveness, dimensional stability, and heat resistance compared to those using conventional polyimide resins. It had characteristics.

Claims (1)

[Claims] Claim 1: 3,3',4,4'-biphenyltetracarboxylic dianhydride as an essential component;
A carboxylic dianhydride component containing 0 to 50 mol% of 4'-benzophenonetetracarboxylic dianhydride and/or bis(3,4-dicarboxyphenyl)ether dianhydride, and general formula (I) ] An aromatic diamine component consisting of an aromatic diamine represented by p-phenylenediamine and 1,3-bis(3-aminophenoxy)benzene at a molar ratio of acid component to diamine component of 0.9 to 1.1. A reacted polyamic acid resin composition.