Stable liquid biuret modified and biuret allophanate modified toluene diisocyanates, prepolymers thereof, and processes for their preparation

1. A stable liquid biuret allophanate modified toluene diisocyanate having an NCO group content of 16 to 46% by weight, and comprising:

(a) a secondary monoamine group containing compound which is selected from the consisting of aliphatic monoamine compounds, aromatic monoamine compounds and araliphatic monoamine compounds;

(b) toluene diisocyanate having an NCO group content of about 48.3% and comprising:

(i) from 0 to 40% by weight of 2,6-toluene diisocyanate, and

(ii) from 60 to 100% by weight of 2,4-toluene diisocyanate,

wherein the %'s by weight of (b)(i) and (b)(ii) total 100% by weight of (b); and

(c) an aliphatic or aromatic alcohol.

2. The stable liquid biuret allophanate modified toluene diisocyanate of claim 1 , wherein the NCO group content ranges from 20 to 40% by weight.

3. The stable liquid biuret allophanate modified toluene diisocyanate of claim 1 , wherein (a) said secondary monoamine group containing compound has a molecular weight of from about 45 to about 600.

4. The stable liquid biuret allophanate modified toluene diisocyanate of claim 1 , wherein (b) said toluene diisocyanate comprises:

(i) from about 20 to about 35% by weight of 2,6-toluene diisocyanate, and

(ii) from about 65 to about 80% by weight of 2,4-toluene diisocyanate,

wherein the %'s by weight of (b)(i) and (b)(ii) total 100% by weight of (b).

5. The stable liquid biuret allophanate modified toluene diisocyanate of claim 1 , wherein (c) said aliphatic alcohol has from 1 to 36 carbon atoms and said aromatic alcohol has from 5 to 20 carbon atoms.

6. A stable liquid prepolymer of biuret modified toluene diisocyanate having an NCO group content of about 6 to about 44% by weight, comprising

(A) a stable liquid secondary amine based biuret modified toluene diisocyanate having an NCO group content of 16 to 46% by weight, which comprises the reaction product of

(a) an aliphatic monoamine compound which is selected from the group consisting of dipropylamine, dibutylamine, dipentylamine, dihexylamine and dioctylamine; and

toluene diisocyanate having an NCO group content of about 48.3% by weight comprising (i) from 0 to 40% by weight of 2,6-toluene diisocyanate, and (ii) from 60 to 100% by weight of 2,4-toluene diisocyanate, with th %'s by weight of (b)(i) and (b)(ii) totaling 100% by weight of (b); and

(B) an isocyanate-reactive component selected from the group consisting of (1) one or more diols having a molecular weight of 76 to 200, (2) one or more polyether polyols having a molecular weight of from 300 to 6000 and containing from about 1.5 to about 6 hydroxyl groups and (3) mixtures thereof.

7. The stable liquid prepolymer of claim 6 , wherein the NCO group content ranges from about 16 to about 36% by weight.

8. The stable liquid prepolymer of claim 6 , wherein (B)(1) diols are selected from the group consisting of 1,3-butanediol, 1,2-propylene glycol, dipropylene glycol, tripropylene glycol and mixtures thereof, and (B)(2) said polyether polyols have molecular weights of from about 400 to about 4,800 and functionalities of from about 1.8 to about 3.

9. A stable liquid prepolymer of biuret allophanate modified toluene diisocyanate having an NCO group content of 6 to 44% and comprising:

(C) the stable liquid biuret allophanate modified toluene diisocyanate of claim 1 ; and

(B) an isocyanate-reactive component selected from the group consisting of (1) one or more diols having a molecular weight of 76 to 200, (2) one or more polyether polyols having a molecular weight of from 300 to 6000 and containing from about 1.5 to about 6 hydroxyl groups and (3) mixtures thereof.

10. The stable liquid prepolymer of biuret allophanate modified toluene diisocyanate of claim 9 , wherein the NCO group content is from about 16 to about 36% by weight.

11. The stable liquid prepolymer of biuret allophanate modified toluene diisocyanate of claim 9 , wherein (B)(1) diols are selected from the group consisting of 1,3-butanediol, 1,2-propylene glycol, dipropylene glycol, tripropylene glycol and mixtures thereof, and (B)(2) said polyether polyols have molecular weights of from about 400 to about 4,800 and functionalities of from about 1.8 to about 3.