Thermally reversible polyester polyurethanes

Claim 2

A polymer as claimed in claim 1 which after being heated for 30 minutes at a temperature between its melting temperature and 30* C above this temperature and then annealed for 30 minutes at a temperature in the range of 100* C to 150* C gives a G.S.W. value of between three times and one half of the value given by said polymer before said heating and annealing and a Sol Fraction of not more than 50 percent.

Claim 3

A polymer according to claim 1 comprising the reaction production of para di(isocyanato cyclohexyl) methane and a copolymer of 1,6-hexamethylene diol, terephThalic acid and 5-hydroxyisophthalic acid.

Claim 4

A polymer according to claim 1 comprising the reaction product of the copolyester of dimethyl terephthalate, dimethyl 5-hydroxy isophthalate and 1,6-hexane diol and para di(isocyanato cyclohexyl) methane.

Claim 5

A polymer according to claim 1 comprising the reaction product of the copolyester of 1,6-hexane diol, dimethyl terephthalate and 3,3''-methylene bis(4-hydroxy benzoic acid) and para di(isocyanato cyclohexyl) methane.

Claim 6

A polymer according to claim 1 comprising the reaction product of para di(isocyanato cyclohexyl) methane and the copolyester of ethylene glycol, adipic acid or succinic acid and 5-hydroxy isophthalic acid or 3,3''-methylene bis(4-hydroxybenzoic acid).

Claim 7

A process for preparing a polyester-urethane segmented polymer of essentially uniform structure, comprising polyester segments with reversibly thermolabile urethane cross-links between neighboring polymer chains, said urethane cross-links being formed by reaction of isocyanate-reactable hydroxyl groups on said polyester segments with a diisocyanate used in amounts such that the isocyanate groups present are essentially equivalent to the number of isocyanate-reactable hydroxyl groups on said segments, said process comprising reacting an essentially linear polyester including isocyanate-reactable hydroxyl groups with a diisocyanate in such amount that the number of available isocyanate groups is substantially equivalent to the number of isocyanate-reactable hydroxyl groups in said polyester, and wherein said polyester is prepared from a multifunctional compound which is an aromatic dicarboxylic acid having at least one other pendant phenolic hydroxyl group capable of reacting with isocyanate to form a urethane, and the proportion of said aromatic dicarboxylic acid being such that not less than one equivalent of phenolic hydroxyl branching function per 100 moles of dicarboxylic acid units in the polyester and not more than one equivalent per 5 moles of dicarboxylic acid units is present.

Claim 8

A process according to claim 8, wherein the diisocyanate is para di(isocyanato cyclohexyl) methane and the polyester is a copolymer of 1,6-hexamethylene diol, terephthalic acid and 5-hydroxyisophthalic acid.

Claim 9

A process according to claim 8, wherein the diisocyanate is para di(isocyanato cyclohexyl) methane and the polyester is the copolyester of dimethyl terephthalate, dimethyl 5-hydroxy isophthalate and 1,6-hexane diol.

Claim 10

A process according to claim 8, wherein the diisocyanate is para di(isocyanato cyclohexyl) methane and the polyester is the copolyester of 1,6-hexane diol, dimethyl terephthalate and 3,3''-methylene bis(4-hydroxy benzoic acid).

Claim 11

A process according to claim 8, wherein the diisocyanate is para di(isocyanato cyclohexyl) methane and the polyester is the copolyester of ethylene glycol, adipic acid or succinic acid and 5-hydroxy isophthalic acid or 3,3''-methylene bis(4-hydroxybenzoic acid).