COLOR-STABLE CURING AGENT COMPOSITIONS COMPRISING POLYISOCYANATES OF (CYCLO)ALIPHATIC DIISOCYANATES

Abstract

Polyisocyanate composition containing (A) at least one polyisocyanate obtainable by reacting at least one monomeric isocyanate, (B) at least one solvent containing a mixture of C7-C14 aromatic hydrocarbons, (C) optionally at least one further solvent, (D) optionally at least one Lewis-acidic organic metal compound capable of accelerating the reaction of isocyanate groups with isocyanate-reactive groups, (E) optionally other coatings additives,
wherein the amount of cumene in component (B) is less than 1 wt %, preferably less than 0.7 wt %.

Claims

1.-13. (canceled)

14. A polyisocyanate composition containing (A) at least one polyisocyanate obtainable by reacting at least one monomeric isocyanate, (B) at least one solvent containing a mixture of C7-C14 aromatic hydrocarbons, (C) optionally at least one further solvent, (D) optionally at least one Lewis-acidic organic metal compound capable of accelerating the reaction of isocyanate groups with isocyanate-reactive groups, (E) optionally other coatings additives, wherein the amount of cumene in component (B) is less than 1 wt %.

15. The polyisocyanate composition according to claim 14 containing the Lewis-acidic organic metal compound (E).

16. The polyisocyanate composition according to claim 14 wherein the monomeric isocyanate is a diisocyanate selected from the group consisting of hexamethylene 1,6-diisocyanate, pentamethylene 1,5-diisocyanate, isophorone diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, 4,4-di(isocyanatocyclohexyl)methane and 2,4-di(isocyanatocyclohexyl)methane.

17. The polyisocyanate composition according to claim 14, wherein the polyisocyanate (A) is a polyisocyanate containing isocyanurate groups, biuret groups and/or asymmetric isocyanurates.

18. The polyisocyanate composition according to claim 14, wherein the solvent naphtha (B) is selected from the group consisting of Solvesso 100 (CAS-Nr. 64742-95-6), Caromax 18, Shellsol, Hydrosol A170 and solvent naphtha; Solvesso 150 and Solvesso 200 (boiling range about 182-207 C., CAS No. 64742-94-5).

19. The polyisocyanate composition according to claim 14, wherein the amount of solvent (B) is higher than 30 w-%, of the total amount of solvents in the composition.

20. The polyisocyanate composition according to claim 14, wherein the further solvent (C) is selected from the group consisting of xylene, (cyclo)aliphatic hydrocarbons, ketones, esters, ethers, ether esters and carbonates.

21. The polyisocyanate composition according to claim 14, wherein the Lewis-acidic organic metal compound (E) comprises a metal selected from the group consisting of tin, zinc, bismuth, titanium, and zirconium, or mixtures thereof.

22. The polyisocyanate composition according to claim 14, wherein the amount of cumene in the total composition is less than 0.1 wt %.

23. The polyisocyanate composition according to claim 14, wherein the amount of polyisocyanate (A) is from 25 wt % to 95 wt % and the amount of solvent (B) is from 5 wt % to 75 wt %.

24. A process for producing polyurethane coatings, comprising reacting the polyisocyanate composition according to claim 14 with at least one binder comprising isocyanate-reactive groups.

25. A process for producing polyurethane coatings, comprising reacting the polyisocyanate composition according to claim 14 with at least one binder selected from the groups consisting of polyacrylate polyols, polyester polyols, polyether polyols, polyurethane polyols, polyurea polyols, polyetherols, polycarbonates, polyester polyacrylate polyols, polyester polyurethane polyols, polyurethane polyacrylate polyols, polyurethane-modified alkyd resins, fatty acid-modified polyester polyurethane polyols, copolymers with allyl ethers and copolymers or graft polymers thereof.

26. A method comprising utilizing the polyisocyanate composition according to claim 14 as a curing agent in at least one selected from the group consisting of coating materials in primers, primer surfacers, pigmented topcoats, basecoats and clearcoats in the sectors of refinishing, automotive refinishing, large vehicle finishing and wood, plastic and OEM finishing, in utility vehicles in the agricultural and construction sector and as curing agent in adhesives and sealants.

Description

EXAMPLES

[0194] The determination of the cumene content in Solvesso was done by GC. The attribution of cumene was done according to GC/MS and with addition of further cumene to confirm the peak and the response factor for quantitative determination of cumene. The cumene content in the polyisocyanate/solvent mixture was not determined.

Polyisocyanates A

PIC A1:

[0195] PIC A1 is obtained by trimerization of hexamethylene diisocyanate by catalysis of tetrabutylphosphonium hydrogen difluoride, 70% in methanol/iso-propanol at 65 C., stopping with para toluene sulfonic acid, 55% in 2-propanol, and distillation. Share of asymmetric isocyanurate to total isocyanurate=45%; ca. 2% uretdione. Viscosity 790 mPa*s, 23.5% NCO. PIC A1 basically contains symmetric and asymmetric isocyanurate groups.

PIC A2:

[0196] Desmodur N 3900, company Covestro. Viscosity 824 mPa*s, ca. 23.5% NCO value. PIC A2 basically contains symmetric and asymmetric isocyanurate groups.

PIC A3:

[0197] Biuret type polyisocyanate based on hexamethylene diisocyanate. Viscosity ca. 8000 mPa*s. NCO value ca. 22.0%.

PIC A4:

[0198] Isocyanurate type polyisocyanate based on hexamethylene diisocyanate. Desmodur N 3300. Viscosity ca. 3000 mPa*s, NCO ca. 21.8%.

Solvent B

[0199] Solvesso 100 (S): CAS-Nr: 64742-95-6. EC-Number: 919-668-5.

[0200] Two Solvesso 100 batches were chosen for our investigations containing 0.66% (examples) or 1.85% (reference) of Solvesso 100 from production materials used in a plant.

Solvents C

[0201] Methoxypropylacetate (MP)

[0202] Xylene (X)

[0203] Butyl acetate (B)

Catalysts D

[0204] Dibutyltindilaurate, Aldrich

[0205] K-KAT 6212, zirconium chelate catalyst, King Industries

Experiments

[0206]

TABLE-US-00001 TABLE 1 Color drift of polyisocyanates [asymmetric isocyanurate] in Solvesso 100 with more or less than 1% of cumene, eventually in mixture with other solvents. 60% polyisocyanate in solvent. 50 C. storage temperature. cumene color no [Hz] Ex PIC solvent % 0 d 7 d 28 d 56 d 84 d Sum* E1 PIC A1 S 0.66 15 44 44 61 93 257 R1 PIC A1 S 1.85 16 45 51 85 119 316 E2 PIC A1 S/B = 1:1 0.66 14 24 38 47 117 240 R2 PIC A1 S/B = 1:1 1.85 13 26 41 53 145 278 E3 PIC A2 S 0.66 15 11 17 20 34 97 R3 PIC A2 S 1.85 15 10 19 26 49 119 *Sum: means the addition of the 5 color values

TABLE-US-00002 TABLE 2 Color drift of polyisocyanates [biuret] in solvents, containing Solvesso 100 with more or less than 1% of cumene. 40% polyisocyanate in solvent. 50 C. storage temperature. cumene color no [Hz] Ex PIC solvent % 0 d 7 d 28 d 56 d 84 d Sum* E4 PIC A3 MP/S*.sup.1 0.66 8 10 27 45 50 140 R4 PIC A3 MP/S*.sup.1 1.85 5 9 31 59 65 169 E5 PIC A3 MP/X/S*.sup.2 0.66 6 14 28 50 49 147 R5 PIC A3 MP/X/S*.sup.2 1.85 7 11 30 50 64 162 E6 PIC A3 MP/X/S*.sup.3 0.66 7 7 9 18 17 58 R6 PIC A3 MP/X/S*.sup.3 1.85 9 7 13 19 19 67 *Sum: means the addition of the 5 color values *.sup.16.7% Methoxypropylacetate MP. 53.3% Solvesso 100 *.sup.26.7% Methoxypropylacetate MP. 6.7% xylene. 46.7% Solvesso 100 *.sup.36.7% Methoxypropylacetate MP. 46.7% xylene. 6.7% Solvesso 100

[0207] The cumene content in the composition of E6 is 0.04 and in R6 is 0.12%.

TABLE-US-00003 TABLE 3 Color drift of polyisocyanates [asymmetric isocyanurate] in Solvesso 100 with more or less than 1% of cumene, 40% polyisocyanate in solvent, in presence of 500 ppm dibutyltindilaurate referring to polyisocyanate. 50 C. storage temperature. cumene color no [Hz] Ex PIC solvent % 0 d 7 d 28 d 56 d 84 d Sum* E7 PIC A1 S 0.66 17 120 297 444 611 1489 R7 PIC A1 S 1.85 17 116 310 472 821 1736 E8 PIC A2 S 0.66 16 77 151 239 352 835 R8 PIC A2 S 1.85 16 64 170 369 529 1148

TABLE-US-00004 TABLE 4 Color drift of polyisocyanates [asymmetric isocyanurate] in Solvesso 100 with more or less than 1% of cumene, 40% polyisocyanate in solvent, in presence of 500 ppm K-KAT 6212 referring to polyisocyanate. 50 C. storage temperature. cumene color no [Hz] Ex PIC solvent % 0 d 7 d 28 d 56 d 84 d Sum* E9 PIC A1 S 0.66 17 55 90 118 141 421 R9 PIC A1 S 1.85 18 56 82 119 153 428

TABLE-US-00005 TABLE 5 Color drift of polyisocyanates [biuret] in Solvesso 100 with more or less than 1% of cumene, in mixture with other solvents, in presence of 500 ppm dibutyltindilaurate referring to polyisocyanate. 40% polyisocyanate in solvent. 50 C. storage temperature. cumene color no [Hz] Ex PIC solvent % 0 d 7 d 28 d 56 d 84 d Sum* E10 PIC A3 MP/S*.sup.1 0.66 9 36 72 87 171 375 R10 PIC A3 MP/S*.sup.1 1.85 7 41 67 100 197 412 E11 PIC A3 MP/X/S*.sup.2 0.66 8 40 62 78 86 274 R11 PIC A3 MP/X/S*.sup.2 1.85 8 32 57 77 137 311 *Sum: means the addition of the 5 color values *.sup.16.7% Methoxypropylacetate MP. 53.3% Solvesso 100 *.sup.26.7% Methoxypropylacetate MP. 6.7% xylene. 46.7% Solvesso 100

TABLE-US-00006 TABLE 6 Color drift of polyisocyanates [isocyanurate] in Solvesso 100 with more or less than 1% of cumene, in presence of 500 ppm dibutyltindilaurate referring to polyisocyanate. 40% polyisocyanate in solvent. 50 C. storage temperature. cumene Color no [Hz] Ex PIC solvent % 0 d 7 d 28 d 56 d 84 d Sum* E12 PIC A4 S 0.66 8 37 51 114 220 430 R12 PIC A4 S 1.85 8 46 67 176 567 864