The reaction of dimer acids, C 6 to C 18 aliphatic dicarboxylic acids, dimer amines, alkylene diamines having from 2 to 8 carbon atoms, and polyoxyalkylene diamines provides polyamides having excellent cold flexibility, high heat resistance, and low moisture absorbency (low water vapor transmission).
1. A polyamide which is the reaction product of a) an acid component comprising at least one dimerized C 12 to C 24 unsaturated fatty acid and at least one C 6 to C 18 aliphatic dicarboxylic acid and b) an amine component comprising at least one alkylene diamine having from 2 to 8 carbon atoms, at least one C 24 to C 48 dimer amine, and at least one polyoxyalkylene diamine.
2. A polyamide according to claim 1 wherein the acid component comprises at least one dimerized C 16 to C 20 unsaturated fatty acid.
3. A polyamide according to claim 1 wherein the at least one dimerized C 12 to C 24 unsaturated fatty acid is prepared using one or more fatty acids selected from the group consisting of oleic acid, linoleic acid, linolenic acid, and mixtures thereof.
4. A polyamide according to claim 1 wherein the acid component comprises at least one dimerized C 18 unsaturated fatty acid.
5. A polyamide according to claim 1 wherein the acid component comprises at least one C 9 to C 14 aliphatic dicarboxylic acid.
6. A polyamide according to claim 1 wherein the acid component comprises sebacic acid.
7. A polyamide according to claim 1 wherein the amine component comprises at least one alkylene diamine having from 2 to 4 carbon atoms.
8. A polyamide according to claim 1 wherein the amine component comprises ethylenediamine.
9. A polyamide according to claim 1 wherein the amine component comprises at least one C 32 to C 40 dimer amine.
10. A polyamide according to claim 1 wherein the amine component comprises at least one C 36 dimer amine.
11. A polyamide according to claim 1 wherein the amine component comprises at least one polyoxyalkylene diamine prepared by polymerizing one or more C 2 to C 4 epoxides to form a polyether polyol having hydroxyl end-groups and converting the hydroxyl end-groups to amine groups.
12. A polyamide according to claim 1 wherein the moieties in the polyamide which are derived from the C 2 –C 8 alkylene diamines and the C 6 to C 18 aliphatic dicarboxylic acids together represent from 45 to 65 mole percent of the total moieties in the polyamide.
13. A polyamide according to claim 1 wherein the moieties in the polyamide which are derived from the polyoxyalkylene diamine preferably represent from 0.1 to 2 mole percent of the total moieties in the polyamide.
14. A polyamide according to claim 1 wherein the equivalent ratio of C 2 –C 8 alkylene diamine to dimer amine is from about 1:0.5 to about 1:1.2.
15. A polyamide according to claim 1 wherein the moieties in the polyamide which are derived from the dimerized fatty acids and the dimer amines together represent from 35 to 55 mole percent of the total moieties in the polyamide.
16. A polyamide according to claim 1 wherein the equivalent ratio of C 2 –C 8 alkylene diamine to polyoxyalkylene diamine is from about 1:0.01 to about 1:0.1.
17. A polyamide according to claim 1 wherein the equivalent ratio of dimer amine to polyoxyalkylene diamine is from about 1:0.01 to about 1:0.1.
18. A polyamide according to claim 1 wherein the equivalent ratio of dimerized unsaturated fatty acids to aliphatic dicarboxylic acids is from about 1:0.7 to about 1:1.7.
19. A polyamide which is the reaction product of a) an acid component comprising at least one dimerized C 16 to C 20 unsaturated fatty acid and at least one C 9 to C 14 aliphatic dicarboxylic acid and b) an amine component comprising at least one alkylene diamine having from 2 to 4 carbon atoms, at least one C 32 to C 40 dimer amine, and at least one polyoxyalkylene diamine comprising oxypropylene moieties and having a number average molecular weight of at least about 460, wherein the equivalent ratio of alkylene diamine to dimer amine is from about 1:0.5 to about 1:1.2, the equivalent ratio of alkylene diamine to polyoxyalkylene diamine is from about 1:0.01 to about 1:0.1, the equivalent ratio of dimer amine to polyoxyalkylene diamine is from about 1:0.01 to about 1:0.1, and the equivalent ratio of dimerized C 16 to C 20 unsaturated fatty acid to C 9 to C 14 aliphatic dicarboxylic acid is from about 1:0.7 to about 1:1.7.
20. A polyamide which is the reaction product of a) an acid component comprising at least one dimerized C 18 unsaturated fatty acid and at least one aliphatic dicarboxylic acid selected from the group consisting of azelaic acid, sebacic acid, and dodecanedicarboxylic acid and b) an amine component comprising ethylene diamine, at least one C 36 dimer amine, and at least one polyoxypropylene diamine having a number average molecular weight of at least about 460, wherein the equivalent ratio of ethylene diamine to C 36 dimer amine is from about 1:0.7 to about 1:1, the equivalent ratio of C 36 dimer amine to polyoxypropylene diamine is from about 1:0.02 to about 1:0.06, the equivalent ratio of ethylene diamine to polyoxypropylene diamine is from about 1:0.02 to about 1:0.06, and the equivalent ratio of dimerized C 18 unsaturated fatty acids to aliphatic dicarboxylic acids is from about 1:1 to about 1:1.4, the moieties in the polyamide which are derived from the ethylene diamine and the aliphatic dicarboxylic acids together represent from 45 to 65 mole percent of the total moieties in the polyamide, the moieties in the polyamide which are derived from the C 36 dimer amine and the dimerized C 18 unsaturated fatty acids together represent from 35 to 55 mole percent of the total moieties in the polyamide, and the moieties in the polyamide which are derived from the polyoxypropylene diamine preferably represent from 0.1 to 2 mole percent of the total moieties in the polyamide.