Modified polyisocyanate

Abstract

The present invention relates to a modified polyisocyanate and use thereof, in particular as a crosslinking component of water-soluble or water-dispersible coatings. The modified polyisocyanate is obtained by a reaction of a system comprising the following components: at least an aminosulfonic acid; at least a polyisocyanate; at least a tertiary amine; and optionally a polyether alcohol containing an ethylene oxide group. The modified polyisocyanate comprises at least an iminooxadiazinedione structure and at least an isocyanurate structure, the weight ratio of the iminooxadiazinedione structure to the isocyanurate structure being 1:300 to 1:5. The amount of sulfonate group of the modified polyisocyanate is 0.75% by weight to 1.1% by weight, based on the amount of the modified polyisocyanate as 100% by weight. The viscosity thereof is 500 mPa.Math.s to 10000 mPa.Math.s, as determined according to DIN EN ISO 3219:1994-10 at a temperature of 23° C. and a shear rate of 10 s.sup.−1. The coating comprising the modified polyisocyanate of the present invention can be manually stirred well, and the resulting coating layer has high gloss and good transparency.

Claims

1. A modified polyisocyanate obtained by a reaction of a system comprising the following components: a. at least an aminosulfonic acid represented by the formula I; ##STR00008## wherein, R1 and R2 each independently represents hydrogen, an aliphatic group having 1 to 18 carbon atoms which is substituted or unsubstituted and/or contains a heteroatom, a cycloaliphatic group having 3 to 18 carbon atoms which is substituted or unsubstituted and/or contains a heteroatom, an aromatic group having 1 to 18 carbon atoms which is substituted or unsubstituted and/or contains a heteroatom; R1 and R2 can react with each other to form a cycloaliphatic group having 3 to 8 carbon atoms or a heterocyclic group having 3 to 8 carbon atoms substituted by an oxygen atom or a nitrogen atom; R3 represents a linear or branched aliphatic group having 2 to 8 carbon atoms; b. at least a polyisocyanate; c. at least a tertiary amine; and d. optionally a polyether alcohol containing an ethylene oxide group; wherein the modified polyisocyanate comprises at least an iminooxadiazinedione structure and at least an isocyanurate structure, the weight ratio of the iminooxadiazinedione structure to the isocyanurate structure being 1:300 to 1:5; the amount of the sulfonate group of the modified polyisocyanate is 0.75% by weight to 1.1% by weight, based on the amount of the modified polyisocyanate as 100% by weight; the viscosity of the modified polyisocyanate is 500 mPa.Math.s to 10000 mPa.Math.s, as determined according to DIN EN ISO 3219:1994-10 at a temperature of 23° C. and a shear rate of 10 s.sup.−1.

2. The modified polyisocyanate according to claim 1, characterized in that the modified polyisocyanate has a weight ratio of the iminooxadiazinedione structure to the isocyanurate structure of 1:200 to 1:5.

3. The modified polyisocyanate according to claim 1, characterized in that the modified polyisocyanate has a viscosity of 500 mPa.Math.s to 7000 mPa.Math.s, as determined according to DIN EN ISO 3219:1994-10 at a temperature of 23° C. and a shear rate of 10 s.sup.−1.

4. The modified polyisocyanate according to claim 1, characterized in that the amount of the sulfonate group of the modified polyisocyanate is 0.75% by weight to 1.0% by weight, based on the amount of the modified polyisocyanate as 100% by weight.

5. The modified polyisocyanate according to claim 1, characterized in that R3 represents a linear or branched aliphatic group having 2 to 4 carbon atoms.

6. The modified polyisocyanate according to claim 1, characterized in that the aminosulfonic acid is one or more of the following compounds: 3-cyclohexylaminopropanesulfonic acid, 4-(cyclohexylamino)-1-butanesulfonic acid and 2-(cyclohexylamino)ethanesulfonic acid.

7. The modified polyisocyanate according to claim 1, characterized in that the amount of the aminosulfonic acid is 1.5% by weight to 3.5% by weight, based on the amount of the components a and b as 100% by weight.

8. The modified polyisocyanate according to claim 1, characterized in that the polyisocyanate comprises at least an iminooxadiazinedione structure and at least an isocyanurate structure, the weight ratio of the iminooxadiazinedione structure to the isocyanurate structure being 1:300 to 1:5.

9. The modified polyisocyanate according to claim 1, characterized in that the polyisocyanate is one or more of the following compounds: an aliphatic polyisocyanate and a cycloaliphatic polyisocyanate.

10. The modified polyisocyanate according to claim 1, characterized in that the polyether alcohol containing an ethylene oxide group has an ethylene oxide group content of 0 to 17% by weight, based on the amount of components of the reaction as 100% by weight.

11. The modified polyisocyanate according to claim 1, characterized in that the modified polyisocyanate is obtained by a reaction of a system comprising the following components: a. 3-cyclohexylaminopropanesulfonic acid; b. a derivative of hexamethylene diisocyanate having an isocyanurate structure and an iminooxadiazinedione structure; and c. a tertiary amine; wherein the weight ratio of the iminooxadiazinedione structure to the isocyanurate structure of the modified polyisocyanate is 1:30 to 1:7, and the amount of the sulfonate group of the modified polyisocyanate is 0.75% by weight to 1.1% by weight, based on the amount of the modified polyisocyanate as 100% by weight; the viscosity of the modified polyisocyanate is 500 mPa.Math.s to 10000 mPa.Math.s, as determined according to DIN EN ISO 3219:1994-10 at a temperature of 23° C. and a shear rate of 10 s.sup.−1.

12. The modified polyisocyanate according to claim 1, characterized in that the modified polyisocyanate is obtained by a reaction of a system comprising the following components: a. 3-cyclohexylaminopropanesulfonic acid, the amount of 3-cyclohexylaminopropanesulfonic acid being 2% by weight to 3% by weight, based on the amount of the components a and b as 100% by weight; b. a derivative of hexamethylene diisocyanate having an isocyanurate structure and an iminooxadiazinedione structure, the weight ratio of the iminooxadiazinedione structure to the isocyanurate structure of the derivative of hexamethylene diisocyanate having an isocyanurate structure and an iminooxadiazinedione structure being preferably 1:30 to 1:20; and c. N,N-dimethylcyclohexylamine present at a molar equivalent ratio of 0.3 to 1.9 based on the sulfonate group of the 3-cyclohexylaminopropanesulfonic acid; wherein the weight ratio of the iminooxadiazinedione structure to the isocyanurate structure of the modified polyisocyanate is 1:30 to 1:20; the amount of the sulfonate group of the modified polyisocyanate is 0.75% by weight to 1.0 weight %, based on the amount of the modified polyisocyanate as 100% by weight; the viscosity of the modified polyisocyanate is 3000 mPa.Math.s to 7000 mPa.Math.s, as determined according to DIN EN ISO 3219:1994-10 at a temperature of 23° C. and a shear rate of 10 s.sup.−1.

13. A coating, an adhesive or a sealant comprising the modified polyisocyanate according to claim 1.

14. A substrate coated with the coating, adhesive or sealant according to claim 13.

15. An aqueous two-component coating comprising at least an aqueous hydroxy resin dispersion, at least a modified polyisocyanate according to claim 1, optionally an auxiliary and optionally an additive.

16. A process for preparing an aqueous two-component coating comprising the steps of: mixing an aqueous hydroxy resin dispersion, optionally an auxiliary, and optionally an additive in any manner to obtain a mixture, mixing the modified polyisocyanate according to claim 1 and said mixture, and stirring manually to obtain the aqueous two-component coating.

17. A product comprising a substrate and a coating formed by applying the aqueous two-component coating according to claim 15 to the substrate.

18. The product according to claim 17, characterized in that the substrate is wood, metal, alloy or an inorganic material.

19. The product according to claim 17, characterized in that the product is furniture.

20. A process for producing a product, comprising the step of applying the aqueous two-component coating according to claim 15 to a substrate, followed by curing and drying.

Description

EXAMPLES

(1) Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art of the present invention. When the definition of a term in this specification contradicts the meaning as commonly understood by those skilled in the art, the definitions described here shall prevail.

(2) Unless stated otherwise, all numbers expressing the amount of ingredients, reaction conditions, and the like, as used in the specification and claims, are understood to be modified by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth herein are approximations that can be varied according to properties as desired.

(3) Unless otherwise stated, “a”, “an”, and “the” as used in this specification are meant to include “at least one” or “one or more”. For example, “a component” refers to one or more components, and thus more than one component may be contemplated and employed or used in the implementation of embodiments.

(4) As used herein, “and/or” refers to one or all of the elements mentioned.

(5) As used herein, “including” and “comprising” encompass the cases in which only the elements mentioned are present and also the cases in which other unmentioned elements are present in addition to the mentioned elements.

(6) All percentages in the present invention are percentages by weight unless otherwise stated.

(7) The analytical measurements of the present invention were carried out at 23° C. unless otherwise stated.

(8) The weight ratio of the iminooxadiazinedione structure to the isocyanurate structure in the polyisocyanate was determined by .sup.13C NMR. The test instrument was Bruker DPX-400. The weight ratio of iminooxadiazinedione structure: isocyanurate structure=1: (integral area @148.4 ppm)/(integral area @147.9 ppm+integral area @144.5 ppm+integral area @135.3 ppm).

(9) In the reaction for preparing the modified polyisocyanate from the polyisocyanate of the present invention, the weight ratio of the iminooxadiazinedione structure to the isocyanurate structure in the modified polyisocyanate is the same as the weight ratio of the iminooxadiazinedione structure to the isocyanurate structure in the polyisocyanate.

(10) The viscosity was determined according to DIN EN ISO 3219:1994-10 at a temperature of 23° C. and a shear rate of 10 s.sup.−1. MV-DIN rotor was selected.

(11) The isocyanate group (NCO) content was determined according to DIN-EN ISO 11909:2007-05.

(12) The measured data refer to free and potentially free NCO content.

(13) Standard of color value test: DIN-EN1557:1997-03.

(14) Standard of gloss test: GB/T 9754-2007.

(15) Standard of haze test: ASTM E430-11.

(16) Raw Materials and Reagents

(17) Polyisocyanate P1: A four-necked flask equipped with a stirrer, a thermometer, a reflux cooling tube, a nitrogen injection tube, and a dropping funnel was set under a nitrogen atmosphere. 850 g of hexamethylene diisocyanate (HDI) was added thereto, and heated to 65° C. with stirring. Then 5.5 g of trimethyl-2-methyl-2-hydroxyethylammonium hydroxide (a solution diluted to 5% by weight with isobutanol) was added as catalyst. When the NCO content of the reaction liquid was 45.6% by weight, the reaction was terminated by adding 1.1 g of di-n-butyl phosphate. The unreacted monomers were removed by a thin film evaporator at temperature of 140° C. and vacuum of 0.05 mbar. A Polyisocyanate P1 was obtained with a nonvolatile content of 100% by weight, a viscosity of 1200 mPa.Math.s (23.5° C.), a NCO content of 23.0% by weight, a HDI monomer concentration of 0.25% by weight, and a weight ratio of iminooxadiazinedione structure to isocyanurate structure of 1:27.57.

(18) Polyisocyanate P2: The method for preparing P1 was carried out. The reaction was terminated when the NCO content of the reaction liquid was 38%. The unreacted monomers were removed by a thin film evaporator at temperature of 140° C. and vacuum of 0.05 mbar. Polyisocyanate P2 was obtained with a nonvolatile content of 100% by weight, a viscosity of 3000 mPa.Math.s (23.5° C.), a NCO content of 21.7% by weight, a HDI monomer concentration of 0.25% by weight, and a weight ratio of iminooxadiazinedione structure to isocyanurate structure of 1:20.28.

(19) Polyisocyanate P3: The method for preparing P1 was carried out. The reaction was terminated when the NCO content of the reaction liquid was 32%. The unreacted monomers were removed by a thin film evaporator at temperature of 140° C. and vacuum of 0.05 mbar. Polyisocyanate P3 was obtained with a nonvolatile content of 100% by weight, a viscosity of 16000 mPa.Math.s (23.5° C.), a NCO content of 20.0% by weight, a HDI monomer concentration of 0.25% by weight, and a weight ratio of iminooxadiazinedione structure to isocyanurate structure of 1:27.57.

(20) Polyisocyanate P4: The method for preparing P1 was carried out. Tetrabutylphosphonium hydrogendifluoride solution was used as catalyst (diluted to 50% with a solvent of isopropanol/methanol with a weight ratio of 2:1). The reaction was terminated by adding dibutyl phosphate when the NCO content of the reaction liquid was 32%. Polyisocyanate P4 was obtained with a nonvolatile content of 100% by weight, a viscosity of 700 mPa.Math.s (23.5° C.), a NCO content of 23.4% by weight, a HDI monomer concentration of 0.25% by weight, and a weight ratio of iminooxadiazinedione structure to isocyanurate structure of 1:1.28.

(21) Tolonate HDT-LV2: a commercial product based on hexamethylene diisocyanate with a NCO content of 23.0% by weight and a HDI monomer concentration of less than 0.5% by weight, a weight ratio of iminooxadiazinedione structure to isocyanurate structure lower than the detection limit, available from VENCOREX.

(22) Tetrabutylphosphonium hydrogendifluoride solution: purchased from Jinjinle Chemical Company.

(23) Isopropanol: purchased from Sigma-Aldrich.

(24) Methanol: purchased from Sigma-Aldrich.

(25) 3-Cyclohexylaminopropanesulfonic acid: purchased from Sigma-Aldrich.

(26) N,N-Dimethylcyclohexylamine: purchased from Sigma-Aldrich.

(27) Trimethyl-2-methyl-2-hydroxyethylammonium hydroxide: purchased from Sigma-Aldrich.

(28) Bayhydrol A 2470: Aqueous hydroxy acrylate dispersion, available from Covestro, Germany.

(29) BYK 028: Silicone defoamer (a mixture of foam-destroying polysiloxanes and hydrophobic particles in polyethylene glycol), purchased from BYK, Germany.

(30) BYK 346: Wetting leveling agent (polyether modified siloxane solution), available from BYK, Germany.

(31) BUTYL CELLOSOLVE: cosolvent, ethylene glycol butyl ether, purchased from Dow Chemical, USA

(32) RHEOVIS PU 1291: Rheology additive, associative thickener: hydrophobic modified ethoxylated urethane, purchased from BASF, Germany.

(33) Modified Polyisocyanate 1

(34) 27 g (0.14 eq) of polyisocyanate P2, 100 g (0.53 eq) of Tolonate HDT-LV2, 3.6 g (0.016 eq) of 3-cyclohexylaminopropanesulfonic acid and 2.08 g (0.016 mol) of dimethylcyclohexylamine were stirred under dry nitrogen at 80° C. for 4 hours and cooled to room temperature. A modified polyisocyanate of the present invention was obtained with the following characteristic data, said modified polyisocyanate being in a form of a colorless transparent solution:

(35) Solid content: 100% by weight NCO content: 20.78% by weight Viscosity (23° C.): 2907 mPa.Math.s Color value (Hazen): 57 Sulfonate group content: 0.98% by weight (sulfonate group means SO.sub.3.sup.− having molar weight of 80 g/mol)

(36) Iminooxadiazinedione/isocyanurate: 1:100

(37) Ethylene oxide group content: 0.0% by weight

(38) Modified Polyisocyanate 2

(39) 215.44 g (1.10 eq) of polyisocyanate P2, 502.5 g (2.72 eq) of polyisocyanate P1, 20.3 g (0.09 eq) of 3-cyclohexylaminopropanesulfonic acid and 11.7 g (0.09 mol) of dimethylcyclohexylamine were stirred under dry nitrogen at 80° C. for 4 hours and cooled to room temperature. A modified polyisocyanate of the present invention was obtained with the following characteristic data, said modified polyisocyanate being in a form of a colorless transparent solution:

(40) Solid content: 100% by weight

(41) NCO content: 21.32% by weight

(42) Viscosity (23° C.): 3293 mPa.Math.s

(43) Color value (Hazen): 18

(44) Sulfonate group content: 0.98% by weight (sulfonate group means SO.sub.3.sup.− having molar weight of 80 g/mol)

(45) Iminooxadiazinedione/isocyanurate: 1:26.07

(46) Ethylene oxide group content: 0.0% by weight

(47) Modified Polyisocyanate 3

(48) 1705 g (8.74 eq) of polyisocyanate P2, 48.3 g (0.22 eq) of 3-cyclohexylaminopropanesulfonic acid and 27.8 g (0.22 mol) of dimethylcyclohexylamine were stirred under dry nitrogen at 80° C. for 4 hours and cooled to room temperature. A modified polyisocyanate of the present invention was obtained with the following characteristic data, said modified polyisocyanate being in a form of a colorless transparent solution:

(49) Solid content: 100% by weight

(50) NCO content: 20.47% by weight

(51) Viscosity (23° C.): 5992 mPa.Math.s

(52) Color value (Hazen): 7

(53) Sulfonate group content: 0.98% by weight (sulfonate group means SO.sub.3.sup.− having molar weight of 80 g/mol)

(54) Iminooxadiazinedione/isocyanurate: 1:21.2

(55) Ethylene oxide group content: 0.0% by weight

(56) Modified Polyisocyanate 4

(57) 657 g (3.37 eq) of polyisocyanate P2, 69.8 g (0.39 eq) of polyisocyanate P4, 20.6 g (0.09 eq) of 3-cyclohexylaminopropanesulfonic acid and 11.9 g (0.09 mol) of dimethylcyclohexylamine were stirred under dry nitrogen at 80° C. for 4 hours and cooled to room temperature. A modified polyisocyanate of the present invention was obtained with the following characteristic data, said modified polyisocyanate being in a form of a colorless transparent solution:

(58) Solid content: 100% by weight

(59) NCO content: 20.11% by weight

(60) Viscosity (23° C.): 6645 mPa.Math.s Color value (Hazen): 18 Sulfonate group content: 0.98% by weight (sulfonate group means SO.sub.3.sup.− having molar weight of 80 g/mol)

(61) Iminooxadiazinedione/isocyanurate: 1:11.35

(62) Ethylene oxide group content: 0.0% by weight

(63) Modified Polyisocyanate 5

(64) 565.01 g (2.90 eq) of polyisocyanate P2, 131 g (0.73 eq) of polyisocyanate P4, 19.7 g (0.09 eq) of 3-cyclohexylaminopropanesulfonic acid and 11.9 g (0.09 mol) of dimethylcyclohexylamine were stirred under dry nitrogen at 80° C. for 4 hours and cooled to room temperature. A modified polyisocyanate of the present invention was obtained with the following characteristic data, said modified polyisocyanate being in a form of a colorless transparent solution:

(65) Solid content: 100% by weight

(66) NCO content: 20.7% by weight

(67) Viscosity (23° C.): 4690 mPa.Math.s

(68) Color value (Hazen): 17

(69) Sulfonate group content: 0.98% by weight (sulfonate group means SO.sub.3.sup.− having molar weight of 80 g/mol)

(70) Iminooxadiazinedione/isocyanurate: 1:7.67

(71) Ethylene oxide group content: 0.0% by weight

(72) Modified Polyisocyanate 6

(73) 718 g (3.68 eq) of polyisocyanate P2, 16.3 g (0.07 eq) of 3-cyclohexylaminopropanesulfonic acid and 8.82 g (0.07 mol) of dimethylcyclohexylamine were stirred under dry nitrogen at 80° C. for 4 hours and cooled to room temperature. A mixture of modified polyisocyanates of the present invention was obtained with the following characteristic data, said mixture of modified polyisocyanates being in a form of a colorless transparent solution:

(74) Solid content: 100% by weight

(75) NCO content: 20.6% by weight

(76) Viscosity (23° C.): 5743 mPa.Math.s

(77) Color value (Hazen): 20

(78) Sulfonate group content: 0.79% by weight (sulfonate group means SO.sub.3.sup.− having molar weight of 80 g/mol)

(79) Iminooxadiazinedione/isocyanurate: 1:21.03

(80) Ethylene oxide group content: 0.0% by weight

(81) Modified Polyisocyanate 7

(82) 125 g (0.6 eq) of modified polyisocyanate 3, 1.92 g (0.005 mol) of monofunctional polyethylene oxide polyether alcohol started from methanol and having an average molecular weight of 350 were stirred under dry nitrogen at 95° C. for 4 hours and cooled to room temperature. A modified polyisocyanate was obtained with the following characteristic data, said modified polyisocyanate being in a form of a colorless transparent solution:

(83) Solid content: 100% by weight

(84) NCO content: 19.46% by weight

(85) Viscosity (23° C.): 9839 mPa.Math.s

(86) Color value (Hazen): 0

(87) Sulfonate group content: 0.96% by weight (sulfonate group means SO.sub.3.sup.− having molar weight of 80 g/mol)

(88) Iminooxadiazinedione/isocyanurate: 1:21.3

(89) Ethylene oxide group content: 1.4% by weight

(90) Comparative Modified Polyisocyanate 1

(91) 718.21 g (3.68 eq) of polyisocyanate P2, 12.78 g (0.06 eq) of 3-cyclohexylaminopropanesulfonic acid and 7.72 g (0.06 mol) of dimethylcyclohexylamine were stirred under dry nitrogen at 80° C. for 4 hours and cooled to room temperature. A comparative modified polyisocyanate was obtained with the following characteristic data, said comparative modified polyisocyanate being in a form of a colorless transparent solution:

(92) Solid content: 100% by weight

(93) NCO content: 20.85% by weight

(94) Viscosity (23° C.): 5296 mPa.Math.s

(95) Color value (Hazen): 14

(96) Sulfonate group content: 0.62% by weight (sulfonate group means SO.sub.3.sup.− having molar weight of 80 g/mol)

(97) Iminooxadiazinedione/isocyanurate: 1:20.89

(98) Ethylene oxide group content: 0.0% by weight

(99) Comparative Modified Polyisocyanate 2

(100) 718.02 g (3.68 eq) of polyisocyanate P2, 15.24 g (0.07 eq) of 3-cyclohexylaminopropanesulfonic acid and 8.82 g (0.07 mol) of dimethylcyclohexylamine were stirred under dry nitrogen at 80° C. for 4 hours and cooled to room temperature. A comparative modified polyisocyanate was obtained with the following characteristic data, said comparative modified polyisocyanate being in a form of a colorless transparent solution:

(101) Solid content: 100% by weight

(102) NCO content: 20.26% by weight

(103) Viscosity (23° C.): 7012 mPa.Math.s

(104) Color value (Hazen): 20

(105) Sulfonate group content: 0.73% by weight (sulfonate group means SO.sub.3.sup.− having molar weight of 80 g/mol)

(106) Iminooxadiazinedione/isocyanurate: 1:20.98

(107) Ethylene oxide group content: 0.0% by weight

(108) Comparative Modified Polyisocyanate 3

(109) 718.1 g (3.68 eq) of polyisocyanate P2, 24 g (0.11 eq) of 3-cyclohexylaminopropanesulfonic acid and 14.01 g (0.11 mol) of dimethylcyclohexylamine were stirred under dry nitrogen at 80° C. for 4 hours and cooled to room temperature. A comparative modified polyisocyanate was obtained with the following characteristic data, said comparative modified polyisocyanate being in a form of a colorless transparent solution:

(110) Solid content: 100% by weight

(111) NCO content: 19.76% by weight

(112) Viscosity (23° C.): 9361 mPa.Math.s

(113) Color value (Hazen): 18

(114) Sulfonate group content: 1.15% by weight (sulfonate group means SO.sub.3.sup.− having molar weight of 80 g/mol)

(115) Iminooxadiazinedione/isocyanurate: 1:21.41

(116) Ethylene oxide group content: 0.0% by weight

(117) Comparative Modified Polyisocyanate 4

(118) 717.9 g (3.42 eq) of polyisocyanate P3, 20.31 g (0.09 eq) of 3-cyclohexylaminopropanesulfonic acid and 11.7 g (0.09 mol) of dimethylcyclohexylamine were stirred under dry nitrogen at 80° C. for 4 hours and cooled to room temperature. A comparative modified polyisocyanate was obtained with the following characteristic data, said comparative modified polyisocyanate being in a form of a colorless transparent solution:

(119) Solid content: 100% by weight

(120) NCO content: 17.64% by weight

(121) Viscosity (23° C.): 32740 mPa.Math.s

(122) Color value (Hazen): 24

(123) Sulfonate group content: 0.98% by weight (sulfonate group means SO.sub.3.sup.− having molar weight of 80 g/mol)

(124) Iminooxadiazinedione/isocyanurate: 1:27.57

(125) Ethylene oxide group content: 0.0% by weight

(126) Comparative Modified Polyisocyanate 5

(127) 428.7 g (2.20 eq) of polyisocyanate P2, 285.12 g (1.58 eq) of polyisocyanate P4, 20.32 g (0.09 eq) of 3-cyclohexylaminopropanesulfonic acid and 11.7 g (0.09 mol) of dimethylcyclohexylamine were stirred under dry nitrogen at 80° C. for 4 hours and cooled to room temperature. A comparative modified polyisocyanate was obtained with the following characteristic data, said comparative modified polyisocyanate being in a form of a colorless transparent solution:

(128) Solid content: 100% by weight

(129) NCO content: 20.9% by weight

(130) Viscosity (23° C.): 3501 mPa.Math.s

(131) Color value (Hazen): 16

(132) Sulfonate group content: 0.98% by weight (sulfonate group means SO.sub.3.sup.− having molar weight of 80 g/mol)

(133) Iminooxadiazinedione/isocyanurate: 1:4.15

(134) Ethylene oxide group content: 0.0% by weight

(135) Process for Preparing Aqueous Two-Component Coatings of Examples and Comparative Examples

(136) Formulation of component A: According to the formulation listed in Table 1, a defoamer, a leveling agent, a cosolvent, a rheology additive and water were sequentially added to the hydroxyacrylic resin or the hydroxypolyurethane resin. It was dispersed at a high speed of 1500 rpm for 20 minutes. Component A was thus obtained.

(137) TABLE-US-00001 TABLE 1 Formulation of component A Formulation Weight/g Bayhydrol A2470 70 BYK 028 0.5 BYK 346 0.5 BUTYL CELLOSOLVE 2 RHEOVIS PU 1291 1 Deionized water 26 Total weight 100

(138) 50 g of component A and the modified polyisocyanate of the present invention or the comparative modified polyisocyanate (the molar ratio of isocyanate groups to hydroxyl groups being 1.5:1) were mixed, manually stirred using a wooden stick for 30 seconds. Aqueous two-component coatings of Examples and Comparative Examples were thus obtained.

(139) Test Method of Water Dispersibility

(140) 7.5 g of water was added to the aqueous two-component coating. The mixture was manually stirred uniformly and filtered by a 100-mesh filter sieve. The residues on the filter sieve were visually observed. The fewer residues exist on the filter sieve, the better is the dispersibility of the modified polyisocyanate in the resin system. According to the amount of the residues on the filter sieve, the dispersibility of the modified polyisocyanate in the resin system was rated as 1 to 3. 1 means a large amount of residues on the filter sieve; 2 means relatively many residues on the filter sieve; 3 means almost no residue on the filter sieve. 1 means the worst, 3 means the best.

(141) Test Conditions for Gloss and Haze

(142) 7.5 g of water was added to the aqueous two-component coatings. The mixture was manually stirred uniformly and filtered by a 100-mesh filter sieve. The filtered coating was applied to a black plastic plate with a wet film thickness of 120 μm, and dried in air. A coating layer was thus obtained and the gloss and haze thereof were measured.

(143) Evaluation standard for gloss and haze: 60° gloss>80, haze value<100. A larger 60° gloss value indicates a higher gloss of a coating layer, and a larger haze value indicates a lower transparency of a coating layer.

(144) Table 2 shows formulations and test results of the aqueous two-component coatings of Examples 1-5 and Comparative Example 1.

(145) Table 3 shows formulations and test results of the aqueous two-component coatings of Examples 3, 6 and Comparative Examples 2-4.

(146) Table 4 shows formulations and test results of the aqueous two-component coatings of Examples 3, 7 and Comparative Example 5.

(147) Table 5 shows formulations and test results of the aqueous two-component coatings of Examples 3, 8 and Comparative Examples 1, 6.

(148) Table 2 Formulations and test results of the aqueous two-component coatings of Examples 1-5 and

Comparative Example 1

(149) TABLE-US-00002 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Comp. Ex. 1 Modified Modified Modified Modified Modified Comparative Modified polyisocyanate polyisocyanate polyisocyanate polyisocyanate polyisocyanate polyisocyanate 1 2 3 4 5 5 Component A Component A Component A Component A Component A Component A Test Results Dispersibility 3 3 3 3 3 1 60° gloss 91 91.3 91.2 89.5 91.7 90.4 Haze value 49.5 39.2 39.6 41.5 42.7 43.9

(150) The weight ratio of the iminooxadiazinedione structure to the isocyanurate structure of the modified polyisocyanates contained in the aqueous two-component coatings of Examples 1-5 was 1:300 to 1:5. Especially 1:100 to 1:5, the aqueous two-component coatings had almost no residue on the filter sieve, and the modified polyisocyanates showed good dispersibility in coating components, i.e., the coatings could be manually stirred well, and the coating layers formed by the coatings showed excellent transparency and gloss.

(151) The weight ratio of the iminooxadiazinedione structure to isocyanurate structure in the comparative modified polyisocyanate contained in the comparative aqueous two-component coating of Comparative Example 1 was 1:4.15. The coating layer formed by the coating showed excellent transparency and gloss. However, the aqueous two-component coating had a large amount of residues on the filter sieve, and the comparative modified polyisocyanate showed poor dispersibility in coating components, i.e., the ability to stir the coating manually was poor.

(152) TABLE-US-00003 TABLE 3 Formulations and test results of aqueous two-component coatings of Examples 3 and 6 and Comparative Examples 2-4 Comp. Comp. Comp. Ex. 2 Ex. 3 Ex. 4 Compar- Compar- Compar- Ex. 3 Ex. 6 ative ative ative Modified Modified modified modified modified polyi- polyi- polyi- polyi- polyi- socyanate socyanate socyanate socyanate socyanate 3 6 1 2 3 Com- Com- Com- Com- Com- ponent ponent ponent ponent ponent A A A A A Test Results Dispersi- 3 3 3 3 2 bility 60° gloss 91.2 81.1 71.8 48.2 91.5 Haze value 39.6 72.6 237 342 47

(153) The content of the sulfonate group of the modified polyisocyanates contained in the aqueous two-component coatings of Examples 3 and 6 was 0.75% by weight to 1.1% by weight. The aqueous two-component coatings had almost no residue on the filter sieve. The modified polyisocyanates had good dispersibility in coating components, i.e., the coatings could be manually stirred well, and the coating layers formed by the coatings had excellent transparency and gloss.

(154) The content of the sulfonate group of the comparative modified polyisocyanate contained in the comparative aqueous two-component coatings of Comparative Example 2-4 was lower or higher than 0.75% by weight to 1.1% by weight. The aqueous two-component coatings had relatively many residues on the filter sieve. The comparative modified polyisocyanates showed poor dispersibility in coating components, i.e., the ability to stir the coating manually was poor. Or, the coating layers formed by the coatings showed poor transparency and gloss.

(155) TABLE-US-00004 TABLE 4 Formulations and test results of the aqueous two-component coatings of Examples 3, 7 and Comparative Example 5 Ex. 3 Ex. 7 Comp. Ex. 5 Modified Modified Comparative modified polyisocyanate 3 polyisocyanate 7 polyisocyanate 4 Component A Component A Component A Test Results Dispersibility 3 3 2 60° gloss 91.2 90.9 59.5 Haze value 39.6 43.2 289

(156) The viscosities of the modified polyisocyanates contained in the aqueous two-component coatings of Examples 3 and 7 were 500 mPa.Math.s to 10000 mPa.Math.s. The aqueous two-component coatings had almost no residue on the filter sieve. The modified polyisocyanates showed good dispersibility in coating components, i.e., the coatings could be manually stirred well. The coating layers formed by the coatings showed excellent transparency and gloss.

(157) The comparative modified polyisocyanate contained in the comparative aqueous two-component coating of Comparative Example 5 had a viscosity of more than 10000 mPa.Math.s. The coating layer formed by the coating showed poor transparency and gloss. The aqueous two-component coating had relatively many residues on the filter sieve. The comparative modified polyisocyanate showed poor dispersibility in coating components, i.e., the ability to stir the coating manually was poor.

(158) TABLE-US-00005 TABLE 5 Formulations and test results of the aqueous two-component coatings of Examples 3 and 8 and Comparative Examples 1 and 6 Ex. 8 Comp. Ex. 6 80% by weight 80% by weight of modified of compar- polyi- ative modified socyanate 3, polyi- Ex. 3 dissolved Comp. Ex. 1 socyanate 5, Modified in propy- Comparative dissolved in polyi- lene glycol modified propylene glycol socyanate methyl ether polyi- methyl ether 3 acetate (MPA) socyanate 5 acetate (MPA) Component Component Component Component A A A A Test Results Dispersi- 3 3 1 3 bility 60° gloss 91.2 90.9 90.4 91 Haze value 39.6 44.6 43.9 43.4

(159) Whether the modified polyisocyanates contained in the aqueous two-component coatings were diluted with an organic solvent or not, the aqueous two-component coatings had almost no residue on the filter sieve. The modified polyisocyanates showed good dispersibility in coating components, i.e., the coatings could be manually stirred well. The coating layers formed by the coatings showed excellent transparency and gloss.

(160) The comparative modified polyisocyanate contained in the comparative aqueous two-component coating of Comparative Example 1 showed poor dispersibility in coating components. After the comparative modified polyisocyanate was diluted with an organic solvent (Comparative Example 6), its dispersibility was improved greatly.

(161) It is apparent to those skilled in the art that the present invention is not limited to the specific details described above, and the present invention may be embodied in other specific forms without departing from the spirit or main features of the present invention. Thus, the embodiments should be considered in all respects as illustrative and not restricting. The scope of the present invention is thus defined by the claims rather than the foregoing description. Thus any change, as long as it falls within the meaning and scope of the equivalents to the claims, is considered as belonging to the present invention.