Water-emulsifiable isocyanates for coatings having an improved gloss

Abstract

The invention relates to new, water-emulsifiable isocyanates, to a process for preparing water-emulsifiable isocyanates, and to the use thereof.

Claims

1. A water-emulsifiable polyisocyanate composition, comprising: (A) a polyisocyanate comprising at least one (cyclo)aliphatic diisocyanate, (B) a compound (B) comprising at least two isocyanate-reactive groups, and at least one group selected from the group consisting of a thioether group (S), a selanyl group (Se), a sulfoxide group (S(O)), and a sulfone group (S(O).sub.2), (C) a compound comprising an isocyanate-reactive group and a dispersive group, and (D) optionally a solvent, wherein a ratio of NCO groups in (A) to isocyanate-reactive groups in (B) and (C) is from 5:1 to 100:1, an ethylene oxide group content, calculated as 44 g/mol, based on a sum of (A), (B), and (C), is at least 12 wt. %, an amount of component (C) is at least 5 and up to 25 wt. %, and the composition has a viscosity at 23 C. of from 2500 mPas to 12 000 mPas.

2. The water-emulsifiable polyisocyanate composition according to claim 1, wherein the at least one (cyclo)aliphatic diisocyanate is selected from the group consisting of hexamethylene diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, isophorone diisocyanate, 4,4-di(isocyanatocyclohexyl)methane, and 2,4-di(isocyanatocyclohexyl)methane.

3. The water-emulsifiable polyisocyanate composition according to claim 1, wherein the polyisocyanate is an isocyanurate of 1,6-hexamethylene diisocyanate.

4. The water-emulsifiable polyisocyanate composition according to claim 1, wherein the component (B) is selected from the group consisting of a compound of (B1), a compound of (B2), a compound of (B3), and a compound of (B4): ##STR00003## where R.sup.4 and R.sup.5 independently are each C.sub.1-C.sub.18 alkylene, oroptionally interrupted by one or more oxygen atoms and/or sulfur atoms, C.sub.2-C.sub.18 alkylene, C.sub.6-C.sub.12 arylene, or C.sub.5-C.sub.12 cycloalkyl, each of which is optionally substituted by a functional group, aryl, alkyl, aryloxy, alkyloxy, halogen, a heteroatom and/or a heterocycle.

5. The water-emulsifiable polyisocyanate composition according to claim 4, wherein R.sup.4 and R.sup.5 independently are selected from the group consisting of 1,2-ethylene, 1,2-propylene, 1,3-propylene, 1,4-butylene, 1,5-pentylene, 1,6-hexylene, 2-methyl-1,3-propylene, 2-ethyl-1,3-propylene, 2,2-dimethyl-1,3-propylene, 2,2-dimethyl-1,4-butylene, 3-oxa-1,5-pentylene, 3,6-dioxa-1,8-octylene, 3,6,9-trioxa-1,11-undecylene, 1,1-, 1,2-, 1,3- or 1,4-cyclohexylene, 1,2- or 1,3-cyclopentylene, 1,2-, 1,3-, or 1,4-phenylene, and 4,4-biphenylene.

6. The water-emulsifiable polyisocyanate composition according to claim 1, wherein the component (B) is selected from the group consisting of 3-thiapentane-1,5-diol (thiodiglycol), 1,5-dimethyl-3-thiapentane-1,5-diol, 1-methyl-3-thiahexane-1,6-diol, 4-thiaheptane-1,7-diol, and 4,4-dihydroxydiphenyl sulfide.

7. The water-emulsifiable polyisocyanate composition according to claim 1, wherein the compound (C) comprises a monoalcohol comprising at least 7 ethylene oxide groups.

8. The water-emulsifiable polyisocyanate composition according to claim 1, wherein the compound (C) comprises a compound of formula
R.sup.1O[X.sub.i].sub.kH where R.sup.1 is C.sub.1-C.sub.18 alkyl, oroptionally interrupted by one or more oxygen atoms and/or sulfur atoms, C.sub.2-C.sub.18 alkyl, C.sub.6-C.sub.12 aryl, C.sub.5-C.sub.12 cycloalkyl, or a five- to six-membered heterocycle comprising oxygen, nitrogen and/or sulfur atoms, k is an integer of from 7 to 30, and each X.sub.i, for i=1 to k, independently of one another, is CH.sub.2CH.sub.2O.

9. The water-emulsifiable polyisocyanate composition according to claim 1, wherein the compound (C) comprises one compound of formula
RG-R.sup.6-DG where RG is at least one isocyanate-reactive group, DG is at least one dispersive group selected from the group consisting of COOH, SO.sub.3H, OPO.sub.3H, and PO.sub.3H, and also an anionic form thereof, which optionally is associated with any desired counterion, and R.sup.6 is an aliphatic, cycloaliphatic, or aromatic radical comprising 1 to 20 carbon atoms.

10. The water-emulsifiable polyisocyanate composition according to claim 1, wherein the compound (C) is selected from the group consisting of mercaptoacetic acid, mercaptopropionic acid, thiolactic acid, mercaptosuccinic acid, glycine, iminodiacetic acid, sarcosine, alanine, -alanine, leucine, isoleucine, aminobutyric acid, hydroxyacetic acid, hydroxypivalic acid, lactic acid, hydroxysuccinic acid, hydroxydecanoic acid, dimethylolpropionic acid, dimethylolbutyric acid, ethylenediaminetriacetic acid, hydroxydodecanoic acid, hydroxyhexadecanoic acid, 12-hydroxystearic acid, aminobenzenesulfonic acids substituted on the ring by alkyl, aminonaphthalenecarboxylic acid, hydroxyethanesulfonic acid, hydroxypropanesulfonic acid, mercaptoethanesulfonic acid, mercaptopropanesulfonic acid, aminomethanesulfonic acid, taurine, aminopropanesulfonic acid, N-alkyl-, -cycloalkyl-, or -aryl-substituted aminomethanesulfonic acid or aminopropanesulfonic acid, and an alkali metal, an alkaline earth metal, or an ammonium salt thereof.

11. The water-emulsifiable polyisocyanate composition according to claim 1, wherein the compound (C) is a phosphoric ester of formulae (Ia) or (Ib) or a mixture thereof ##STR00004## where R.sup.10 and R.sup.11 independently are alkyl, cycloalkyl, aryl, or aralkyl.

12. A method for making a coating material, the method comprising: incorporating the water-emulsifiable polyisocyanate composition according to claim 1 into the coating material, wherein the coating material is suitable for wood, wood veneer, paper, board, card, textile, leather, nonwoven, plastics surface, glass, ceramic, mineral building material, metal, or coated metal.

13. The water-emulsifiable polyisocyanate composition according to claim 1, wherein the compound (C) is a phosphoric ester of formulae (Ia) or (Ib) or a mixture thereof ##STR00005## where R.sup.10 and R.sup.11 have formula (II)
R.sup.12O[X.sub.i].sub.n(II) where R.sup.12 is C.sub.1 to C.sub.20 alkyl, n is 0 or a positive integer from 1 to 20, and each X.sub.i, for i=1 to n, is independently selected from the group consisting of CH_CH.sub.2O, CH.sub.2CH(CH.sub.3)O, and CH(CH.sub.3)CH.sub.2O.

14. The water-emulsifiable polyisocyanate composition according to claim 1, wherein when the composition is applied to a substrate and cured to form a coating, the coating has a gloss determined at an angle of 20 of 54.6 to 71.8.

15. The water-emulsifiable polyisocyanate composition according to claim 1, which comprises 0.5 to 15 wt. %, based on the sum of (A), (B) and (C).

16. The water-emulsifiable polyisocyanate composition according to claim 1, which comprises 1 to 10 wt. %, based on the sum of (A), (B) and (C).

17. A water-emulsifiable polyisocyanate composition, comprising in at least partially reacted form: (A) a polyisocyanate comprising at least one (cyclo)aliphatic diisocyanate, (B) a compound (B) comprising at least two isocyanate-reactive groups, and at least one group selected from the group consisting of a thioether group (S), a selanyl group (Se), a sulfoxide group (S(O)), and a sulfone group (S(O).sub.2), and (C) a compound comprising an isocyanate-reactive group and a dispersive group, wherein a ratio of NCO groups in (A) to isocyanate-reactive groups in (B) and (C) is from 5:1 to 100:1, an ethylene oxide group content, calculated as 44 g/mol, based on a sum of (A), (B), and (C), is at least 12 wt. %, an amount of component (C) is at least 5 and up to 25 wt. %, and the composition has a viscosity at 23 C. of from 2500 mPas to 12 000 mPas.

18. The water-emulsifiable polyisocyanate composition according to claim 17, which further comprises (D) a solvent.

19. A method for making a coating material, the method comprising: incorporating the water-emulsifiable polyisocyanate composition according to claim 17 into the coating material, wherein the coating material is suitable for wood, wood veneer, paper, board, card, textile, leather, nonwoven, plastics surface, glass, ceramic, mineral building material, metal, or coated metal.

20. The water-emulsifiable polyisocyanate composition according to claim 1, wherein the component (B) is selected from the group consisting of a compound of (B2), a compound of (B3), and a compound of (B4): ##STR00006## where R.sup.4 and R.sup.5 independently are each C.sub.1-C.sub.18 alkylene, oroptionally interrupted by one or more oxygen atoms and/or sulfur atoms, C.sub.2-C.sub.18 alkylene, C.sub.6-C.sub.12 arylene, or C.sub.5-C.sub.12 cycloalkyl, each of which is optionally substituted by a functional group, aryl, alkyl, aryloxy, alkyloxy, halogen, a heteroatom and/or a heterocycle.

Description

EXAMPLES

(1) In this specification, unless indicated otherwise, parts are to be understood as meaning parts by weight.

(2) Polyisocyanate A:

(3) HDI isocyanurate having an NCO content of 22.2% and a viscosity of 2800 mPa*s at 23 C. (available commercially as Basonat HI 100 from BASF SE, Ludwigshafen).

(4) Polyether A:

(5) Monofunctional polyethylene oxide, prepared starting from methanol and with potassium hydroxide catalysis, having an OH number of 112 (according to DIN 53240) and a molecular weight of 500 g/mol. The basic catalyst residues still present were subsequently neutralized with acetic acid and the product was desalted. The same procedure also removes potassium acetate that has formed.

(6) Diols

(7) Thiodyglycol HP (from BASF SE, Ludwigshafen) 1,5 Pentanediol Diethylene glycol

Inventive Examples 1 to 3, Comparative Examples 4 to 7

(8) 100 g of polyisocyanate A, the amount of polyether A specified in the table, and the amount of the stated diol (B) specified in the table were mixed, heated, and reacted with one another. After 3 hours at 90 C. the reaction was discontinued when the stated NCO content was reached, corresponding to the complete formation of the urethane. The corresponding product had a viscosity at 23 C. as reported in the table.

(9) TABLE-US-00001 Polyisocyanate Polyether NCO content Viscosity Example amount (g) amount (g) Diol amount (g) (%) (mPa .Math. s) 1 100 17.6 2.0 g 15.8 5500 thiodiglycol 2 100 17.6 2.5 g 15.0 8200 thiodiglycol 3 100 17.6 3.7 g 14.2 14 600 thiodiglycol 4 (comp.) 100 17.6 0 17.0 2950 5 (comp.) 100 17.6 3.1 g 14.2 13 200 1,5-pentanediol 6 (comp.) 100 17.6 3.2 g 14.1 22 500 diethylene glycol 7 (comp.) 100 48.4 0 11.2 3850

Use Examples

(10) 100 g of Luhydran S938T (acrylate-based aqueous polyol, available commercially from BASF SE, Ludwigshafen, OH number 100 mg KOH/g, 45% strength in water) were mixed with 2.5 g of butyl diglycol acetate and 6.7 g of butyl glycol acetate as film-forming assistants. Using 0.9 g of a 50% strength solution of dimethylethanolamine in water, the pH of the mixture was adjusted to 8.5. The application viscosity was adapted using 7.8 g of water and 0.52 g of BYK 340 (from BYK) defoamer.

(11) The polyisocyanates from the table above were diluted with dipropylene glycol dimethyl ether to a solids content of 80%.

(12) These polyisocyanate solutions were added, in an amount corresponding to 1 NCO to 1 OH of the Luhydran, to 45 g of the polyol formulation, and the mixture was stirred by hand at 140 to 180 revolutions per minute with a wooden spatula for 20 seconds.

(13) A bar coater was then used to draw down films onto card in a wet film thickness of 150 m.

(14) After curing had taken place at 60 C. for 30 minutes, the gloss was determined at an angle of 20 using a micro-TRI-gloss p apparatus from BYK.

(15) TABLE-US-00002 Example Gloss (20) 1 54.6 2 59.4 3 71.8 4 (comparative) 43.8 5 (comparative) 51.0 6 (comparative) 56.9 7 (comparative) 49.6

(16) The comparison of inventive examples 1 to 3 with comparative example 4 (same amount of polyether) shows a distinct improvement in the gloss when using the polyisocyanates of the invention.

(17) In examples 3, 5, and 6, the same molar amount of different diols with the same chain length was used. Here again, a distinct improvement in the gloss is apparent through use of component (B) in the polyisocyanates of the invention.

(18) In inventive example 3 and comparative example 7, equal molar amounts were used of OH components, which in comparative example 7 come exclusively from the polyether, with omission of the component (B) of the invention. Here again, a distinct improvement in the gloss is apparent through use of component (B) in the polyisocyanates of the invention.