Liquid partially trimerized and allophanized polyisocyanates based on toluene diisocyanate and diphenylmethane diisocyanate

1. A process for the preparation of a storage-stable, liquid, partially trimerized and allophanized polyisocyanate composition containing isocyanurate groups and having an NCO group content of about 15 to about 41% by weight, comprising:

(1) partially trimerizing and allophanizing:

(A) from 5 to 85% by weight of toluene diisocyanate having an isomer distribution of:

(1) from 60 to 100% by weight of the 2,4-isomer,

and

(2) from 0 to 40% by weight of the 2,6-isomer, with the sum of the %'s by weight of (A)(1) and (A)(2) totaling 100% by weight of (A);

and

(B) from 5 to 85% by weight of a polyisocyanate of the diphenylmethane series comprising:

(1) from 0 to 50% by weight of polyisocyanates of the diphenylmethane series having an isocyanate functionality greater than 2,

(2) from 40 to 100% by weight of 4,4′-diphenylmethane diisocyanate,

(3) from 0 to 20% by weight of 2,4′-diphenylmethane diisocyanate,

and

(4) from 0 to 6% by weight of 2,2′-diphenylmethane diisocyanate,

with the sum of the %'s by weight of (B)(1), (B)(2), (B)(3) and (B)(4) totaling 100% by weight of (B);

and

(C) from 0.1 to 10% by weight of an organic compound or mixture thereof containing from 1 to 4 hydroxyl groups capable of reacting with NCO groups and having a molecular weight of from 32 to 6000;

wherein the sum of the %'s by weight of (A), (B) and (C) total 100% by weight,

in the presence of:

(D) at least one trimerization catalyst and optionally at least one allophanation catalyst,

followed by addition of:

(E) an acidic stopper.

2. The process of claim 1 , wherein the storage-stable, liquid, partially trimerized and allophanized polyisocyanate composition has an NCO group content of about 17 to about 39% by weight, and comprises:

(A) from 10 to 80% by weight of toluene diisocyanate having an isomer distribution of:

(1) from 60 to 100% by weight of the 2,4-isomer,

and

(2) from 0 to 40% by weight of the 2,6-isomer, with the sum of the %'s by weight of (A)(1) and (A)(2) totaling 100% by weight of (A);

and

(B) from 10 to 80% by weight of a polyisocyanate of the diphenylmethane series comprising:

(1) from 0 to 50% by weight of polyisocyanates of the diphenylmethane series having an isocyanate functionality greater than 2,

(2) from 40 to 100% by weight of 4,4′-diphenylmethane diisocyanate,

(3) from 0 to 20% by weight of 2,4′-diphenylmethane diisocyanate,

and

(4) from 0 to 6% by weight of 2,2′-diphenylmethane diisocyanate,

with the sum of the %'s by weight of (B)(1), (B)(2), (B)(3) and (B)(4) totaling 100% by weight of (B);

and

(C) from 0.1 to 10% by weight of an organic compound or mixture thereof containing from 1 to 4 hydroxyl groups capable of reacting with NCO groups and having a molecular weight of from 32 to 6000

wherein the sum of the %'s by weight of (A), (B) and (C) total 100% by weight.

3. A process according to claim 1 , wherein (C) is an aliphatic alcohol having from 1 to 36 carbon atoms or an aromatic alcohol having from 5 to 20 carbon atoms.

4. A process according to claim 3 , wherein (C) is chosen from at least one of methanol, ethanol, 1,2-ethanediol, 1-propanol, 2-propanol, 1-butanol, isobutyl alcohol 2-butanol, n-amyl alcohol, sec-amyl alcohol, tert-amyl alcohol, 1-ethyl-1-propanol, n-hexanol and isomers thereof, n-octyl alcohol, 2-octyl alcohol, 2-ethyl-1-hexanol, n-decyl alcohol, n-dodecyl alcohol, neopentylglycol, n-tetradecyl alcohol, n-hexadecyl alcohol, n-octadecyl alcohol, 1,2and 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 2,3-butanediol, 3-methyl-2-butanol, 3,3-dimethyl-1-butanol, 2-ethyl-1,3-hexanediol, glycerol, 1,2,4-butanetriol, pentaerythritol, diethylene glycol, dipropylene glycol, diethylene glycol, triethylene glycol and phenol.

5. A process according to claim 4 , wherein (C) is isobutyl alcohol.

6. A process for preparing a storage-stable, liquid, partially trimerized and allophanized polyisocyanate composition containing isocyanurate groups and having an NCO group content of about 15 to about 41% by weight, comprising:

(1) partially trimerizing and allophanizing:

(A) from 5 to 85% by weight of toluene diisocyanate having an isomer distribution of:

(1) from 60 to 100% by weight of the 2,4-isomer,

and

(2) from 0 to 40% by weight of the 2,6-isomer, with the sum of the %'s by weight of (A)(1) and (A)(2) totaling 100% by weight of (A);

and

(B) from 5 to 85% by weight of a polyisocyanate of the diphenylmethane series comprising:

(1) from 0 to 50% by weight of polyisocyanates of the diphenylmethane series having an isocyanate functionality greater than 2,

(2) from 40 to 100% by weight of 4,4′-diphenylmethane diisocyanate,

(3) from 0 to 20% by weight of 2,4′-diphenylmethane diisocyanate,

and

(4) from 0 to 6% by weight of 2,2′-diphenylmethane diisocyanate,

with the sum of the %'s by weight of (B)(1), (B)(2), (B)(3) and (B)(4) totaling 100% by weight of (B);

and

(C) from 0.1 to 10% by weight of an organic compound or mixture thereof containing from 1 to 4 hydroxyl groups capable of reacting with NCO groups and having a molecular weight of from 32 to 6000;

wherein the sum of the %'s by weight of (A), (B) and (C) total 100% by weight

in the presence of:

(D) at least one trimerization catalyst and optionally at least one allophanation catalyst,

followed by addition of:

(E) an acidic stopper; and

(2) blending

(F) a polyisocyanate of the diphenylmethane series comprising:

(1) from 0 to 50% by weight, based on total weight of (F), of polyisocyanates of the diphenylmethane series having an isocyanate functionality greater than 2,

(2) from 30 to 60% by weight, based on total weight of (F), of 4,4′-MDI,

(3) from 3 to 60% by weight, based on total weight of (F), of 2,4′-MDI; and

(4) from 0 to 6% by weight, based on total weight of (F), of 2,2′-MDI; or

(G) a uretonimine modified polyisocyanate of the diphenylmethane series comprising:

(1) from 34 to 100% by weight, based on total weight of (G), of 4,4′-MDI,

(2) from 0 to 60% by weight, based on total weight of (G), of 2,4′-MDI, and

(3) from 0 to 6% by weight, based on total weight of (G), of 2,2′-MDI