Light stable polyurethane elastomer prepared from aliphatic isocyanate using thio tin organic compound containing sulfur attached to tin as heat activated catalyst

A curable solvent-free liquid composition consisting essentially of a mixture of a macropolyol which is a polyester or polyether glycol having a molecular weight of from 500 to 2000, a monomeric hydrocarbon-containing aliphatic diisocyanate, and, as a chain extender, an alkane diol having from 3 to 6 carbon atoms, the equivalence ratio of isocyanate groups to hydroxyl groups in the said composition being from 0.90:1 to 1.1.:1 and the equivalence ratio of said macropolyol to said chain extender being from 1:1 to 1:3, the said mixture containing, in amount effective to catalyze the cure of the mixture, a thio tin organic compound of the formula

• (R-).sub.a Sn [-S(R.sup.1).sub.x ].sub.b
• wherein:
• R is an alkyl radical having 3 to 10 carbon atoms;
• R.sup.1 is an alkyl radical having 4 to 20 carbon atoms or a radical of the formula --R.sup.2 COOR.sup.3 where R.sup.2 is (CH.sub.2).sub.n, n being from 1 to 5, and R.sup.3 is an alkyl radical having 4 to 18 carbon atoms;
• x is zero or 1, a is 2 or 3, and b is 1 or 2,
• the said composition have a pot life of at least 25 minutes at room temperature and being capable of curing in from 30 seconds to 3 minutes at corresponding temperatures of from 375.degree. to 300.degree.F. to form a solid, chain extended light-stable polyurethane elastomer.

In a method of making a shaped object by reacting a composition consisting essentially of a mixture of a macroglycol, a monomeric hydrocarbon-containing aliphatic polyisocyanate, a bifunctional chain extender, and a catalyst effective to cure the mixture to form a solid chain extended light-stable polyurethane elastomer, wherein the composition is mixed in liquid form and is thereafter shaped and cured in the desired shape, the improvement comprising effecting the reaction in the presence of an effective amount of a thio tin organic compound having sulfur directly attached to the tin, the said organic compound having the formula:

• (R-).sub.a SN[-S(R.sup.1).sub.x ].sub.b
• wherein:
• R is an alkyl radical having 3 to 10 carbon atoms;
• R.sup.1 is an alkyl radical having 4 to 20 carbon atoms or a radical of the formula --R.sup.2 COOR.sup.3 where R.sup.2 is (CH.sub.2).sub.n, n being from 1 to 5, and R.sup.3 is an alkyl radical having 4 to 18 carbon atoms;
• x is zero or 1, a is 2 or 3, and b is 1 or 2;
• the equivalence ratio or isocyanate groups to hydroxyl groups in said composition being from 0.9:1 to 1.1:1, whereby the composition has a pot life of at least 25 minutes at room temperature but cures rapidly at corresponding temperatures of from 300.degree. to 375.degree.F.

In a method of making a solid polyurethane article by reacting a curable liquid composition consisting essentially of a polyester or polyether glycol, a monomeric hydrocarbon-containing cycloaliphatic diisocyanate, a chain extender which is an alkane diol having 3 to 6 carbon atoms, and an effective amount of a heat activatable catalyst for the cure of the composition, wherein the said liquid is first shaped at ambient temperature and thereafter heated to an elevated temperature to cure the composition in a desired shape, the improvement comprising effecting the reaction in the presence of, as the catalyst, an organo tin compound of the formula

• (R-).sub.a Sn[-S(R.sup.1).sub.x ].sub.b
• wherein:
• R is an alkyl radical having 3 to 10 carbon atoms;
• R.sup.1 is an alkyl radical having 4 to 20 carbon atoms or a radical of the formula --R.sup.2 COOR.sup.3 where R.sup.2 is (CH.sub.2).sub.n, n being from 1 to 5, and R.sup.3 is an alkyl radical having 4 to 18 carbon atoms;
• x is zero or 1, a is 2 or 3, and b is 1 or 2;
• the equivalence ratio of isocyanate groups to hydroxyl groups in the said mixture being from 0.90:1 to 1.1:1 whereby the said liquid has a pot life of at least 25 minutes at 22.degree.C. but cures rapidly at a temperature of from 300.degree. to 375.degree.F. to form a solid, chain extended light-stable polyurethane elastomer.

A method of making a light-stable polyurethane coated fabric comprising providing a solvent-free liquid mixture of a macropolyol selected from the group consisting essentially of polyester and polyether glycols having a molecular weight of from 500 to 2000, a monomeric hydrocarbon-containing aliphatic diisocyanate, a chain extender which is an alkane diol having 3 to 6 carbon atoms, and a catalyst in amount effective to catalyze the cure of the said mixture at a curing temperature of from 300.degree. to 375.degree.F. the said catalyst being an organotin compound of the formula

• (R-).sub.a Sn[-S(R.sup.1).sub.x ].sub.b
• wherein:
• R is an alkyl radical having 3 to 10 carbon atoms;
• R.sup.1 is an alkyl radical having 4 to 20 carbon atoms or a radical of the formula --R.sup.2 COOR.sup.3 where R.sup.2 is (CH.sub.2).sub.n, n being from 1 to 5, and R is an alkyl radical having 4 to 18 carbon atoms;
• x is zero or 1, a is 2 or 3, and b is 1 or 2, the equivalence ratio of isocyanate groups to hydroxyl groups in the said mixture being from 0.90:1 to 1.1:1 and the equivalence ratio of said macropolyol to said alkane diol being from 1:1 to 1:3, the said mixture being characterized by a pot life of at least 25 minutes at 22.degree.C., thereafter applying the said liquid mixture to a fabric, and heating the resulting assembly to curing temperature to cure the applied mixture to a solid elastomeric state.