Polymercaptans for curing epoxy resins and method of preparation thereof

Claim 2

A polymercaptan particularly useful for curing epoxy resins to impart particular resistance to the absorption of water by the resultant thermoset polymers comprising: a propoxylated ether polythiol of the structure ##STR9## wherein y is an integer of at least 1, x is an integer of at least 2, and R is a polyol consisting of atoms of carbon, hydrogen, and oxygen having from 2 to 6 hydroxyl groups and free of reactive functional groups and the total number of carbon atoms in R and ##STR10## is greater than 15.

Claim 3

A polymercaptan according to claim 1 wherein R equals pentaerythritol.

Claim 4

A polymercaptan according to claim 1 wherein R equals dipentaerythritol.

Claim 5

A polymercaptan according to claim 1 wherein R equals glycerin.

Claim 6

A polymercaptan according to claim 1 wherein R equals propylene glycol.

Claim 7

A polymercaptan according to claim 1 wherein R equals trimethylolpropane.

Claim 8

A polymercaptan according to claim 1 wherein R equals sorbitol.

Claim 9

A thermoset polymer resulting from the reaction of a propoxylated ether polythiol and an epoxy resin in the presence of an amine catalyst comprising: a propoxylated ether polythiol of the structure ##STR11## wherein y is an integer of at least 1, x is an integer of at least 2 and R is polyol consisting of atoms of carbon, hydrogen and oxygen having from 2 to 6 hydroxyl groups and free of reactive functional groups, and the total number of carbon atoms in R and ##STR12## is greater than 15; and an epoxy resin wherein the resultant thermoset polymer exhibits a water absorption rate over a period of not less than six weeks of less than 0.050 grams per square inch (0.00775 grams per square centimeter) when reacted in the presence of an amine catalyst.

Claim 10

A thermoset polymer resulting from the reaction of a propoxylated ether polythiol and an epoxy resin in the presence of an amine catalyst comprising: a propoxylated ether polythiol of the structure ##STR11## wherein y is an integer of at least 1, x is an integer of at least 2 and R is polyol consisting of atoms of carbon, hydrogen and oxygen having from 2 to 6 hydroxyl groups and free of reactive functional groups, and the total number of carbon atoms in R and ##STR12## is greater than 15; and an epoxy resin wherein the resultant thermoset polymer exhibits a water absorption rate over a period of not less than six weeks of less than 0.050 grams per square inch (0.00775 grams per square centimeter) when reacted in the presence of an amine catalyst.

Claim 11

A thermoset polymer according to claim 8 having a Shore D hardness of greater than 50.

Claim 12

A process for the manufacture of polymercaptans useful in curing epoxy resins to produce thermoset polymers which exhibit particular resistance the absorption of water comprising the steps of: introducing into a reactor an allyl ether, sufficient benzene to produce a benzene to allyl ether ratio in the range of 10/1 to .001/1, and an azo catalyst having a low decomposition temperature; introducing hydrogen sulfide to obtain a substantial excess over the stoichiometric amount so that the reactants are saturated under a pressure in the range of 80 to 388 psi (5.6 to 27.3 kg. per sq. cm.) and at a temperature in the range of 20° to 90° C; gradually raising the temperature within the range of 20° to 90° C to promote the reaction; after a period of time in the range of 0 to 15 hours, venting the excess hydrogen sulfide; cooling the reaction mixture to nearly room temperature; and stripping the solvent from the reaction mixture to obtain the polymercaptan product.

Claim 13

A process for the manufacture of polymercaptans useful in curing epoxy resins to produce thermoset polymers which exhibit particular resistance the absorption of water comprising the steps of: introducing into a reactor an allyl ether, sufficient benzene to produce a benzene to allyl ether ratio in the range of 10/1 to .001/1, and an azo catalyst having a low decomposition temperature; introducing hydrogen sulfide to obtain a substantial excess over the stoichiometric amount so that the reactants are saturated under a pressure in the range of 80 to 388 psi (5.6 to 27.3 kg. per sq. cm.) and at a temperature in the range of 20° to 90° C; gradually raising the temperature within the range of 20° to 90° C to promote the reaction; after a period of time in the range of 0 to 15 hours, venting the excess hydrogen sulfide; cooling the reaction mixture to nearly room temperature; and stripping the solvent from the reaction mixture to obtain the polymercaptan product.