IPC분류정보
국가/구분 |
United States(US) Patent
공개
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0668137
(2008-07-11)
|
공개번호 |
US-0331432
(2010-12-30)
|
우선권정보 |
JP-2007-182549(2007-07-11); JP-2007-283597(2007-10-31) |
국제출원번호 |
PCT/JP2008/062562
(2008-07-11)
|
발명자
/ 주소 |
- Arai, Tatsuya
- Yamaguchi, Hiroaki
|
출원인 / 주소 |
|
대리인 / 주소 |
|
인용정보 |
피인용 횟수 :
0 인용 특허 :
0 |
초록
▼
A polyimide foam formed of an aromatic polyimide prepared from a 3,3′,4,4′-biphenyltetracarboxylic acid component and an aromatic diamine component. The polyimide foam has flexibility at least such that no cracking occurs when a specimen of the polyimide foam with a 1 cm by 1 cm cross-
A polyimide foam formed of an aromatic polyimide prepared from a 3,3′,4,4′-biphenyltetracarboxylic acid component and an aromatic diamine component. The polyimide foam has flexibility at least such that no cracking occurs when a specimen of the polyimide foam with a 1 cm by 1 cm cross-section and a length of 5 cm is deformed until both ends thereof come into contact with each other to make a closed loop. The polyimide foam is obtained by dissolving a 3,3′,4,4′-biphenyltetracarboxylic acid component and an aromatic diamine component in a solvent in the presence of an acid phosphoric ester having a specific structure to prepare a polyimide precursor and heating the polyimide precursor to expand.
대표청구항
▼
1. A process for producing a polyimide foam comprising the steps of dissolving an aromatic tetracarboxylic acid component and an aromatic diamine component in a solvent in the presence of an acid phosphoric ester represented by chemical formula (1): wherein the definitions of R1, R2, and R3 are
1. A process for producing a polyimide foam comprising the steps of dissolving an aromatic tetracarboxylic acid component and an aromatic diamine component in a solvent in the presence of an acid phosphoric ester represented by chemical formula (1): wherein the definitions of R1, R2, and R3 are selected from the following combinations of substituents: (a) R1 is OH, and R2 and R3 are each independently OR; (b) R1 and R2 are each OH, and R3 is OR; and (c) R1 is CH2COOY, and R2 and R3 are each independently OR; wherein R is an alkyl group having 1 to 25 carbon atoms or an alkenyl group having 1 to 25 carbon atoms, the alkyl group and the alkenyl group being optionally substituted with an alkoxy group having 1 to 25 carbon atoms or an alkyl group having 1 to 5 carbon atoms; and Y is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, to prepare a polyimide precursor and heating the polyimide precursor to cause the polyimide precursor to expand. 2. The process according to claim 1, wherein the aromatic tetracarboxylic acid component is a 3,3′,4,4′-biphenyltetracarboxylic acid component. 3. The process according to claim 1, wherein the acid phosphoric ester is present in an amount of 0.1 to 10 parts by mass per 100 parts by mass of the total of the aromatic tetracarboxylic acid component and the aromatic diamine component. 4. The process according to claim 1, wherein the acid phosphoric ester has a decomposition temperature of 180° C. or higher. 5. The process according to claim 1, wherein the polyimide precursor has the form of a green body of powder. 6. The process according to claim 1, further comprising, before the step of heating, the step of mixing the polyimide precursor with at least one compound that is liquid at ambient temperature and selected from the group consisting of water, an alcohol, and an ether. 7. The process according to claim 1, wherein the heating is microwave heating. 8. The process according to claim 1, further comprising, after the step of heating to expand, the step of post-heating the polyimide foam at a temperature higher than the glass transition temperature of the polyimide constituting the polyimide foam. 9. A polyimide foam produced by the process according to claim 1. 10. A polyimide foam comprising an aromatic polyimide prepared from a 3,3′,4,4′-biphenyltetracarboxylic acid component and an aromatic diamine component, the polyimide foam having flexibility at least such that no cracking occurs when a specimen of the polyimide foam with a 1 cm by 1 cm cross-section and a length of 5 cm is deformed until both ends thereof come into contact with each other to make a closed loop. 11. The polyimide foam according to claim 10, having cushioning properties such that, when a 2 cm-side cubic specimen of the polyimide foam is compressed by applying a load to one surface of the specimen to a thickness of 0.2 cm, held in the compressed state for 30 seconds, and released from the load, the permanent strain in thickness is 10% or less. 12. The polyimide foam according to claim 10, having cells with a diameter ranging from 1 to 1000 μm occupying at least 80% of a cross-sectional area of the foam. 13. The polyimide foam according to claim 10, wherein the aromatic diamine component is m-phenylenediamine, 3,4′-oxydianiline, 2,4-diaminotoluene, or a mixture thereof. 14. A polyimide foam comprising an aromatic polyimide prepared from a 3,3′,4,4′-biphenyltetracarboxylic acid component and an aromatic diamine component and having an expansion ratio of at least 150 (an apparent density of 0.0092 g/cm3 or less). 15. A process for producing the polyimide foam according to claim 10, comprising the steps of dissolving the 3,3′,4,4′-biphenyltetracarboxylic acid component and the aromatic diamine component in a solvent in the presence of an acid phosphoric ester represented by chemical formula (1): wherein the definitions of R1, R2, and R3 are selected from the following combinations of substituents: (a) R1 is OH, and R2 and R3 are each independently OR; (b) R1 and R2 are each OH, and R3 is OR; and (c) R1 is CH2COOY, and R2 and R3 are each independently OR; wherein R is an alkyl group having 1 to 25 carbon atoms or an alkenyl group having 1 to 25 carbon atoms, the alkyl group and the alkenyl group being optionally substituted with an alkoxy group having 1 to 25 carbon atoms or an alkyl group having 1 to 5 carbon atoms; and Y is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, to prepare a polyimide precursor and heating the polyimide precursor to cause the polyimide precursor to expand. 16. The process according to claim 2, wherein the acid phosphoric ester is present in an amount of 0.1 to 10 parts by mass per 100 parts by mass of the total of the aromatic tetracarboxylic acid component and the aromatic diamine component. 17. The polyimide foam according to claim 11, having cells with a diameter ranging from 1 to 1000 μm occupying at least 80% of a cross-sectional area of the foam.
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