Claims
- 1. A method of preparing polyamide acid useful for processing of semi-conductors from (i) at least one diamine and (ii) a tetracarboxylic acid dianhydride in an inert solvent, which comprises the steps of
- (1) reacting (i) at least one diamine and (ii) a tetracarboxylic acid dianhydride, at a temperature below 40.degree. C. to form a polyamide acid having a reduced viscosity above 0.5 dl/g at 30.degree. C., and
- (2) heating said polyamide acid in an inert solvent at a temperature between 50.degree. C. and 100.degree. C. and a trace of amount of water to lower the viscosity of said polyamide acid whereby the reducing viscosity of said polyamide acid is more than 0.3 dl/g at 30.degree. C. and the solution viscosity of said polyamide acid in the inert solvent is 500 to 3,000 centipoises at 25.degree. C.,
- the reduced viscosity being measured by forming a 0.1 dl/g solution of said polyamide acid in dimethylsulfoxide and measuring the viscosity of the solution with a Ubbelohde's viscometer in accordance with Japanese Industrial Standard K 5400, and the solution viscosity being measured by measuring the viscosity of the solution of said polyamide acid in dimethylsulfoxide with a Brookfield type viscometer in accordance with Japanese Industrial Standard K 6901.
- 2. The method of claim 1, wherein the reaction of said diamine to form said polyamide acid is carried out until said reduced viscosity at 30.degree. C. reaches above 0.7 dl/g in the first step of said method, and wherein said polyamide acid is heated to adjust reduced viscosity to between 0.35 and 0.45 dl/g and the solution viscosity to between 800 and 1,500 centipoises at 25.degree. C. in said second step of said method.
- 3. The method of claim 2, wherein
- said diamine is selected from the group consisting of 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, 4,4'-diaminodiphenyl sulfide, benzidine, m-phenylene-diamine, p-phenylenediamine, 1,5-naphthalenediamine and 2,6-naphthalenediamine; and
- said tetracarboxylic acid dianhydride is selected from the group consisting of pyromellitic acid dianhydride, 3,3'4,4'-diphenyltetracarboxylic acid dianhydride, 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride, cyclopentanetetracarboxylic acid dianhydride, 1,2,5,6-naphthalenetetracarboxylic acid dianhydride, 2,3,6,7-naphthalenetetracarboxylic acid dianhydride, 2,3,5,6-pyridinetetracarboxylic acid dianhydride, 1,4,5,8-naphthalenetetracarboxylic acid dianhydride, 3,4,9,10-perylenetetracarboxylic acid dianhydride and 4,4'-sulfonyldiphthalic acid dianhydride.
- 4. The method of claim 2, wherein 4,4'-diaminodiphenyl ether is reacted with pyromellitic acid dianhydride in the reaction step (1).
Priority Claims (1)
Number |
Date |
Country |
Kind |
53-84295 |
Jul 1978 |
JPX |
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Parent Case Info
This is a continuation of application Ser. No. 54,429 filed July 3, 1979, now abandoned.
US Referenced Citations (5)
Non-Patent Literature Citations (1)
Entry |
Patent Gazette-Pat. Appln. No. 44-100 883/69 Miyadera et al. |
Continuations (1)
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Number |
Date |
Country |
Parent |
54429 |
Jul 1979 |
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