Polyurethane polymer having bisphenol group and photoimageable composition containing the same
The present invention provides a polymer having the structure of formula (I) wherein n, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , a, b and c are as defined in the specification. The present invention also provides a negative-acting photoimageable composition comprising the above-mentioned polymer of formula (I), which is suitable for the fabrication of printed circuit boards.
1. A polymer having the formula (I),
wherein:
R 1 is hydrogen or methyl;
R 2 is C 2-4 alkyleneoxy;
R 3 is C 3-10 lactone residue;
R 4 is C 1-20 alkylene;
R 5 is C 2-4 alkyleneoxy;
R 6 is hydrogen or C 1-6 alkyl;
n is 1 or an integer greater than 1;
a is an integer from 1 to 10;
b is an integer from 1 to 20; and
c is an integer from 1 to 10;
wherein the polymer has an average molecular weight between 5,000 and 8,000.
2. The polymer according to claim 1 , wherein a is an integer from 1 to 7.
3. The polymer according to claim 1 , wherein b is an integer from 4 to 15.
4. The polymer according to claim 1 , wherein n is an integer from 1 to 20.
5. The polymer according to claim 1 , wherein R 2 is C 2-3 alkyleneoxy.
6. The polymer according to claim 1 , wherein R 3 is C 3-7 lactone residue.
7. The polymer according to claim 1 , wherein R 4 is C 4-16 alkylene.
8. The polymer according to claim 1 , wherein R 5 is C 2-3 alkyleneoxy.
9. A photoimageable composition, comprising the following components:
(A) the polymer of formula (I) as defined in claim 1 ;
(B) a polymeric binder; and
(C) a photoinitiator.
10. The composition according to claim 9 , wherein the polymer comprises about 5% to about 50% of the total weight of the photoimageable composition.
11. The composition according to claim 9 , wherein the polymeric binder comprises about 30% to about 80% of the total weight of the photoimageable composition.
12. The composition according to claim 9 , wherein the photoinitiator comprises about 1.5% to about 20% the total weight of the photoimageable composition.
13. The composition according to claim 9 , wherein the polymeric binder comprises an acid functional monomer and a non-acid functional monomer as the polymerized units.
14. The polymer according to claim 1 , wherein R 6 is methyl.