Soft thermoplastic polyurethane for blown film application

Claim 2

An essentially linear film forming thermoplastic polyurethane elastomer comprising the reaction product of: (a) a random mixed hydroxyl terminated polyester of the formula (I) ##STR4## said polyester having a molecular weight of about 1800 to about 3600 and having essentially the structure of the reaction product of at least two straight chain aliphatic glycols containing from 2 to about 10 carbon atoms; (b) an aromatic glycol chain extender of the formula (II) HO--Y--OH, aliphatic diol chain extenders other than small adventitious amounts not exceeding 0.75 percent of the weight of said polyester (a) being absent, and (c) an isocyanate of the formula (III) OCN--Z--NCO wherein (1) A is at least two alkylene radicals, oxydialkylene radicals or mixture thereof containing from 2 to about 10 carbon atoms, and B is an alkylene radical containing from 2 to about 10 carbon atoms or an arylene radical containing from 6 to about 12 carbon atoms or a mixture thereof, Y is a phenylenedialkylene or phenyleneoxyalkylene radical containing from about 8 to about 14 carbon atoms; and Z is a divalent organic radical; (2) The value of m is such that said polyester has a molecular weight from about 1800 to about 3600; (3) the molar ratio of said chain extender to said polyester is from about 0.75 to about 2; (4) the molar quantity of said isocyanate is substantially equal to the sum of the molar quantities of said polyester and said chain extender, and (5) said elastomer has a modulus at 100 percent elongation of 350 to 700 psi.

Claim 3

A polyurethane elastomer according to claim 1 wherein A is a mixture of alkylene radicals.

Claim 4

A polyurethane elastomer according to claim 1, said elastomer having alternating hard and soft segments wherein the hard segments comprise repeating groups of the formula IV ##STR5##

Claim 5

A polyurethane elastomer according to claim 1 wherein the molar ratio of said two aliphatic glycols is in the range of 90:10 to 10:90.

Claim 6

A polyurethane elastomer according to claim 4 wherein said aliphatic glycols are 1,4-butanediol and 1,6-hexanediol and said dicarboxylic acid is adipic acid.

Claim 7

A polyurethane elastomer according to claim 4 wherein said aliphatic glycols are ethylene glycol and 1,6-hexanediol and said dicarboxylic acid is adipic acid.

Claim 8

A polyurethane elastomer according to claim 1 wherein said chain extending agent is hydroquinone bis(beta-hydroxyethyl)ether.

Claim 9

A polyurethane elastomeric according to claim 1 wherein said polyester is the reaction product of ethylene glycol, 1,6-hexanediol and adipic acid, the chain extender is hydroquinone bis(betahydroxyethyl)ether and the diisocyanate is 4,4'diphenylmethane diisocyanate.

Claim 10

A polyurethane elastomer according to claim 1 wherein said polyester is the reaction product of 1,4-butanediol, 1,6-hexanediol and adipic acid, the chain extender is hydroquinone bis(betahydroxyethyl)ether and the diisocyanate is 4,4'-diphenylemethane diisocyanate.

Claim 11

A polyurethane elastomer according to claim 1 wherein said isocyanate is 4,4-diphenylmethane diisocyanate, 1,5-naththalene diisocyanate, meta-phenylene diisocyanate or para-phenylene diisocyanate.

Claim 12

A polyurethane elastomer according to claim 10 wherein said isocyanate is 4,4-diphenylmethane diisocyanate.

Claim 13

A thermoplastic polyurethane elastomer according to claim 1 having the following physical properties: (a) Simulated blocking at 135° C. of not over 10 pli without lubricant added; (b) Initial set after 200% extension of not over 25%; and (c) Tear propagation resistance of at least 150 pli.

Claim 14

A thermoplastic polyurethane elastomer according to claim 12, said elastomer also having the following physical properties: a Durometer "A" hardness of about 68 to about 84.

Claim 15

A polyurethane elastomer according to claim 1 wherein said dicarboxylic acid is an aliphatic dicarboxylic acid.

Claim 16

An essentially linear thermoplastic polyurethane elastomer comprising the reaction product of: (a) a random mixed hydroxyl terminated polyester of the formulas (I) ##STR6## said polyester having a molecular weight of about 1800 to about 3600 and having essentially the structure of the reaction product of at least two straight chain aliphatic glycols containing from 2 to about 10 carbon atoms; (b) an aromatic glycol chain extender of the formula (II) HO--Y--OH, aliphatic diol chain extenders other than small adventitious amounts not exceeding 0.75 percent of the weight of said polyester (a) being absent, and (c) an isocyanate of the formula (III) OCN--Z--NCO wherein (1) A is at least two alkylene radicals, oxydialkylene radicals or mixture thereof containing from 2 to about 10 carbon atoms, and B is an alkylene radical containing from 2 to about 10 carbon atoms or an arylene radical containing from 6 to about 12 carbon atoms or a mixture thereof, Y is a phenylenedialkylene or phenyleneoxyalkylene radicals containing from about 8 to about 14 carbon atoms; and Z is a divalent organic radical; (2) the value of m is such that said polyester has a molecular weight from about 1800 to about 3600; (3) the molar ratio of said chain extender to said polyester is from about 0.75 to about 2; (4) the molar quantity of said isocyanate is substantially equal to the sum of the molar quantities of said polyester and said chain extender, and (5) said elastomer has a modulus at 100 percent elongation of 350 to 700 psi, said elastomer being in the form of a film.

Claim 17

An essentially linear thermoplastic polyurethane elastomer comprising the reaction product of: (a) a random mixed hydroxyl terminated polyester of the formulas (I) ##STR6## said polyester having a molecular weight of about 1800 to about 3600 and having essentially the structure of the reaction product of at least two straight chain aliphatic glycols containing from 2 to about 10 carbon atoms; (b) an aromatic glycol chain extender of the formula (II) HO--Y--OH, aliphatic diol chain extenders other than small adventitious amounts not exceeding 0.75 percent of the weight of said polyester (a) being absent, and (c) an isocyanate of the formula (III) OCN--Z--NCO wherein (1) A is at least two alkylene radicals, oxydialkylene radicals or mixture thereof containing from 2 to about 10 carbon atoms, and B is an alkylene radical containing from 2 to about 10 carbon atoms or an arylene radical containing from 6 to about 12 carbon atoms or a mixture thereof, Y is a phenylenedialkylene or phenyleneoxyalkylene radicals containing from about 8 to about 14 carbon atoms; and Z is a divalent organic radical; (2) the value of m is such that said polyester has a molecular weight from about 1800 to about 3600; (3) the molar ratio of said chain extender to said polyester is from about 0.75 to about 2; (4) the molar quantity of said isocyanate is substantially equal to the sum of the molar quantities of said polyester and said chain extender, and (5) said elastomer has a modulus at 100 percent elongation of 350 to 700 psi, said elastomer being in the form of a film.

Claim 18

A polyurethane elastomer film according to claim 15, said film being in the form of a strip.

Claim 19

A process for preparing an essentially linear film forming thermoplastic polyurethane elastomer having a modulus at 100 percent elongation of 350 to 700 psi, which comprises reacting: (a) a random mixed hydroxyl terminated polyester of the formula (I) ##STR7## A is at least two alkylene radicals, oxydialkylene radicals or mixture thereof containing from 2 to about 10 carbon atoms, B is an alkylene radical containing from 2 to about 10 carbon atoms or an arylene radical containing from 6 to about 12 carbon atoms or a mixture thereof, and the value of m is such that said polyester has a molecular weight from about 1800 to about 3600; said polyester having a molecular weight of about 1800 to about 3600 and having essentially the structure of the reaction product of at least two straight chain aliphatic glycols containing from 2 to about 10 carbon atoms; (b) an aromatic glycol chain extender of the formula (II) HO--Y--OH, wherein Y is a phenylendialkylene or phenyleneoxyalkylene radical containing from about 8 to about 14 carbon atoms, aliphatic diol chain extenders other than small adventitious amounts not exceeding 0.75 percent of the weight of said polyester (a) being absent; and (c) an isocyanate of the formula (III) OCN--Z--NCO wherein Z is a divalent organic radical; the molar ratio of said chain extender to said polyester being from about 0.75 to about 2; and the molar quantity of said isocyanate being substantially equal to the sum of the molar quantities of said polyester and said chain extender, and recovering a thermoplastic polyurethane elastomer.

Claim 20

A process for preparing an essentially linear film forming thermoplastic polyurethane elastomer having a modulus at 100 percent elongation of 350 to 700 psi, which comprises reacting: (a) a random mixed hydroxyl terminated polyester of the formula (I) ##STR7## A is at least two alkylene radicals, oxydialkylene radicals or mixture thereof containing from 2 to about 10 carbon atoms, B is an alkylene radical containing from 2 to about 10 carbon atoms or an arylene radical containing from 6 to about 12 carbon atoms or a mixture thereof, and the value of m is such that said polyester has a molecular weight from about 1800 to about 3600; said polyester having a molecular weight of about 1800 to about 3600 and having essentially the structure of the reaction product of at least two straight chain aliphatic glycols containing from 2 to about 10 carbon atoms; (b) an aromatic glycol chain extender of the formula (II) HO--Y--OH, wherein Y is a phenylendialkylene or phenyleneoxyalkylene radical containing from about 8 to about 14 carbon atoms, aliphatic diol chain extenders other than small adventitious amounts not exceeding 0.75 percent of the weight of said polyester (a) being absent; and (c) an isocyanate of the formula (III) OCN--Z--NCO wherein Z is a divalent organic radical; the molar ratio of said chain extender to said polyester being from about 0.75 to about 2; and the molar quantity of said isocyanate being substantially equal to the sum of the molar quantities of said polyester and said chain extender, and recovering a thermoplastic polyurethane elastomer.

Claim 21

A process according to claim 17 wherein said polyester, said chain extender and said isocyanate are reacted in a single step.