Thioethers having a high sulfur content and method therefor
AssigneeProducts Research & Chemical Corp.
InventorsLester Morris, Hakam Singh, Jonathan D. Zook
Life of this patent
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Abstract
Liquid polythioethers containing no oxygen in the polymeric backbone and a method for producing same which includes condensing an organic compound having primary mercaptan group with an organic compound having secondary hydroxyl group beta to a sulfur atom.
Claims36
A liquid polythioether containing no oxygen in the polymeric backbone which is non-crystallizing and water and fuel resistant having the following formula:
- ##STR20## wherein each of R.sub.2 and R.sub.3 is hydrogen or lower alkyl, each of R.sub.1 and R.sub.4 is lower alkyl, R is lower alkylene or lower alkyl thioether, p is 0 to 3, n is from about 8 to 200, r is 0 or 1, a is 0 or 1, m is 1, 3 or 4, the sum of a and r being 1, when m is 1, r is 1 and when m is 3 or 4, a is 1, R' is an organic divalent radical having no chemically reactive groups of an organic primary dimercaptan having the formula R'--(SH).sub.2, each mercaptan group being primary and R" is a tri- or tetravalent organic fragment having no chemically reactive groups of the organic compound having the formula R"--(Z).sub.q wherein Z is a secondary hydroxyl located beta to a sulfur atom or a primary mercaptan group and q is 3 or 4.
A liquid polythioether having no oxygen in the polymeric backbone and 2 to 4 terminal secondary hydroxyl groups which is non-crystallizing and water and fuel resistant and has the following formula:
- ##STR21## wherein R.sub.6 is hydrogen or lower alkyl, R.sub.5 is lower alkyl, s is 2, 3 or 4, n is from about 8 to 200, u is 0 or 1, R.sup.iv is a di-, tri- or tetravalent organic fragment having no chemically reactive groups of the organic polyhydroxy compound R.sup.iv --(OH).sub.s wherein each hydroxyl group is secondary and located beta to a sulfur atom, and R'" is a divalent organic radical having no chemically reactive groups.
A liquid polythioether containing no oxygen and 2 to 4 terminal primary mercaptan groups which is non-crystallizing and water and fuel resistant and has the formula:
- ##STR22## wherein R.sub.5 is lower alkyl, R.sub.6 is hydrogen or lower alkyl, u is 0 or 1, n is from about 8 to 200, w is 2, 3 or 4, R'" is a divalent organic radical having no chemically active groups and R.sup.v is the organic fragment of the polymercaptan compound R.sup.v --(SH).sub.w wherein each mercaptan group is primary.
A method for producing a liquid polythioether which is non-crystallizing, is water and fuel resistant and has a molecular weight of between about 900 to about 25,000 which comprises forming a reaction admixture of (i) a di-secondary beta thioether diol reactant having the formula:
- ##STR23## wherein each of R.sub.2 and R.sub.3 is hydrogen or lower alkyl, each of R.sub.1 and R.sub.4 is lower alkyl, R is lower alkylene or lower alkyl thioether and p is 0 to 3, (ii) an organic primary dimercaptan reactant having the formula:
- R'--(SH).sub.2
- wherein R' is a divalent organic radical and the mercaptan groups are primary, (iii) a catalytic effective amount of a non-oxidizing, strong acid dehydration catalyst in a sufficient amount of water to prevent said catalyst from oxidizing the reactants;
- and (iv) a branching agent reactant of the formula:
- R"--(Z).sub.q
- wherein q is 3 or 4 and R" is a tri- or tetravalent organic radical having no chemically reactive groups, Z is a secondary hydroxyl located beta to a sulfur atom or a primary mercaptan group;
- heating said reactants to a temperature of between about 90.degree. C. and 140.degree. C. to react substantially only the primary mercaptan group with the hydroxyl group and removing a sufficient amount of the water formed by the reaction to prevent the reaction from terminating until a liquid polythioether is formed having a molecular weight of between about 900 to about 25,000.
A method for producing a liquid polythioether which is non-crystallizing, is water and fuel resistant and has a molecular weight of between about 900 to about 25,000, which comprises forming a reaction admixture of (i) a secondary beta-hydroxy mercaptan reactant having the formula:
- ##STR24## wherein --SH is primary, R.sub.5 is lower alkyl, R.sub.6 is hydrogen or lower alkyl, t and u are each 0 or 1 the sum of u and t being 1, when t is 1, R.sub.6 is hydrogen, and R'" is divalent organic radical;
- (ii) a catalytic effective amount of a non-oxidizing, strong acid dehydration catalyst in a sufficient amount of water to prevent said catalyst from oxidizing the reactants;
- and (iii) a polyhydroxy initiator reactant having the formula:
- R.sup.iv --(OH).sub.s
- wherein R.sup.iv is a di-, tri- or tetravalent organic compound having no chemically reactive groups, s is 2, 3 or 4 and each of the --OH groups are secondary and beta to a sulfur atom;
- or (iv) a polymercaptan initiator reactant having the formula:
- R.sup.v --(SH).sub.w
- wherein R.sup.v is an organic radical having no chemically reactive groups, the --(SH) groups are primary and w is 2, 3 or 4;
- heating said reactants to a temperature of between about 90.degree. C. and 140.degree. C. to react substantially only the primary mercaptan group with the hydroxyl group and removing a sufficient amount of the water formed by the reaction to prevent the reaction from terminating until a liquid polythioether is formed having a molecular weight of between about 900 to about 25,000.
Dependencies are inferred from the claim text.