Polyimide compositions having resistance to water sorption, and methods relating thereto
Water absorption resistant polyimide pastes (or solutions), are particularly useful to make electronic screen printable pastes and the electronic components made from these pastes. A group of soluble polyimides and their solvents were discovered to be particularly resistant to moisture absorption. These polyimide solutions optionally contain polyimides also containing cross-linkable monomers and/or thermal cross-linking agents. In addition, these polyimide pastes may optionally contain adhesion promoting agents, blocked isocyanates, metals, metal oxides, and other inorganic fillers. The polyimide pastes (or solutions) of the present invention have a polyimide with a glass transition temperature greater than 250° C., have a water absorption factor of less than 2%, and a have a positive solubility measurement.
1. A polyimide based composition consisting essentially of a polyimide component and an organic solvent, the polyimide component being represented by formula I:
wherein X is O, S(O) 2 , C(CF 3 ) 2 , or a mixture of two or three of O, S(O) 2 , and C(CF 3 ) 2 ;
wherein Y is diamine component selected from the group consisting of m-phenylenediamine (MPD), 3,4′-diaminodiphenyl ether (3,4′-ODA), 4,4′-diamino-2,2′-bis(trifluoromethyl)biphenyl (TFMB), 3,3′-diaminodiphenyl sulfone (3,3′-DDS), bis-(4-(4-aminophenoxy)phenyl)sulfone (BAPS) or 9,9-bis(4-aminophenyl)fluorene (FDA);
with the proviso that:
i. if X is O, then Y is not m-phenylenediamine (MPD), bis-(4-(4-aminophenoxy)phenyl)sulfone (BAPS) and 3,4′-diaminodiphenyl ether (3,4′-ODA);
ii. if X is S(O) 2 , then Y is not 3,3′-diaminodiphenyl sulfone (3,3′-DDS);
iii. if X is C(CF 3 ) 2 , then Y is not m-phenylenediamine (MPD), bis-(4-(4-aminophenoxy)phenyl)sulfone (BAPS), 9,9-bis(4-aminophenyl)fluorene (FDA), and 3,3′-diaminodiphenyl sulfone (3,3′-DDS);
wherein the organic solvent:
i. is a liquid capable of suspending or dissolving the polyimide,
ii. has a Hanson polar solubility parameter between and including any two of the following numbers 2.5, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, and 10.0; and
iii. has a normal boiling point between and including any two of the following numbers 180, 190, 200, 210, 220, 230, 240 and 250° C.
wherein the organic solvent is a member of a group consisting of:
a. a liquid represented by formula II:
and wherein R 5 is H, CH 3 , or CH 3 CH 2 ;
b. a liquid represented by formula III:
wherein R 6 is H, CH 3 , CH 3 CH 2 , or OCH 3 and wherein R 7 is H, CH 3 , or CH 3 CH 2 ;
c. a liquid represented by formula IV:
wherein R 8 is CH 3 , or CH 3 CH 2 and wherein R 9 is H, CH 3 , or CH 3 CH 2 ;
d. 2-phenoxyethanol;
e. tetrahydrofurfural acetate; and
f. combinations thereof.
2. A composition in accordance with claim 1 , wherein the organic solvent comprises a liquid represented by formula II:
and wherein R 5 is H, CH 3 , or CH 3 CH 2 .
3. A composition in accordance with claim 1 , wherein the organic solvent is a liquid represented by formula III:
and wherein R 6 is H, CH 3 , CH 3 CH 2 , or OCH 3 and wherein R 7 is H, CH 3 , or CH 3 CH 2 .
4. A composition in accordance with claim 1 , wherein the organic solvent is a liquid represented by formula IV:
and wherein R 8 is CH 3 , or CH 3 CH 2 and wherein R 9 is H, CH 3 , or CH 3 CH 2 .
5. A composition in accordance with claim 1 , wherein the organic solvent is selected from the group consisting of 2-phenoxyethanol and tetrahydrofurfural acetate.
6. A composition according to claim 1 wherein the polyimide component is present in the composition wherein A is the polyimide component and B is the sum of the polyimide component and the organic solvent, and wherein A is between, and including, any two of the following numbers 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.15, 0.20, 0.40, 0.60, 1.0, 2.0, 3.0, 4.0, and 5.0 and B is 100.
7. A composition according to claim 1 wherein A is between, and including, any of the two following numbers 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29 and 30 and B is 100.
8. A composition according to claim 1 further comprising from 0 to 30 mole percent of the diamine component is selected from the group consisting of 3,3′-dihydroxy-4,4′-diaminobiphenyl (HAB), 2,4-diaminophenol, 2,3-diaminophenol, 3,3′-diamino-4,4′-dihydroxy-biphenyl, and 2,2′-bis(3-amino-4-hydroxyphenyl)hexafluoropropane.
9. A composition according to claim 1 further comprising a thermal crosslinking agent selected from the group consisting of bisphenol epoxy resin, an epoxidized copolymer of phenol and aromatic hydrocarbon, a polymer of epichlorohydrin and phenol formaldehyde, and 1,1,1-tris(p-hydroxyphenyl)ethane triglycidyl ether.
10. A composition according to claim 1 further comprising a blocked isocyanate.
11. A composition according to claim 1 further comprising a metal adhesion agent selected from group consisting of polyhydroxyphenylether (PKHH), polybenzimidazole, and polyamideimide.
12. A composition according to claim 1 further comprising a metal or metal oxide.
13. A composition according to claim 12 wherein the metal or metal oxide is pretreated with a silane or titanate agent.