Aqueous dispersion of polyurethane

Abstract

The present invention relates to an aqueous dispersion of polyurethane and a method for preparing the same, use thereof in a coating composition, and a coated product. The aqueous dispersion of polyurethane comprises a polyurethane polymer which is obtained by a reaction of a reaction mixture comprising a polyurethane prepolymer A) and an isocyanate-reactive component B), said polyurethane prepolymer A) being obtained by a reaction comprising the following components: A1) a polyisocyanate which has a functionality of not less than 2; and A2) a multifunctional polyether polyol which has a functionality of not less than 3 in an amount of 1% to 30% by weight, based on the amount of said reaction mixture as 100% by weight. The aqueous dispersion of polyurethane according to the present invention is well dispersed, and is capable of forming a coat with good waterproof, moisture permeability and washing resistance.

Claims

1. An aqueous dispersion of polyurethane, comprising a polyurethane polymer produced by a reaction of a reaction mixture comprising a polyurethane prepolymer A) and an isocyanate-reactive component B), wherein the polyurethane prepolymer A) is produced by a reaction of: A1) a polyisocyanate which has a functionality of not less than 2; and A2) a multifunctional polyether polyol which has a functionality of not less than 3 in an amount of 1% to 30% by weight, based on the amount of the reaction mixture as 100% by weight, the multifunctional polyether polyol having a number-average molecular weight of 1,800 g/mol to 12,000 g/mol, wherein the multifunctional polyether polyol is produced by a reaction of ethylene oxide and an initiator and has a star structure, and wherein the multifunctional polyether polyol has the following structure: ##STR00002## wherein, m is 0 to 50; n is 1 to 50; m′ is not less than 3; X is one or more selected from the group consisting of propyl, isopropyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, styryl, methylstyryl and pinanyl.

2. The aqueous dispersion of polyurethane according to claim 1, wherein initiator is one or more selected from the group consisting of monosaccharides, oligosaccharides, polysaccharides, pentaerythritol, dipentaerythritol, tripentaerythritol, trimethylolethane, trimethylolpropane, sorbitol, 1,12-dodecanediol, 1,2-decanediol, 1,10-decanediol, cyclic polyol, aromatic hydroxyl compound, polyamine, compounds having carboxylic acid groups, and compounds having hydroxyl and carboxylic acid groups.

3. The aqueous dispersion of polyurethane according to claim 1, wherein the multifunctional polyether polyol is present in an amount of 1 to 15% by weight, based on the amount of said reaction mixture as 100% by weight.

4. The aqueous dispersion of polyurethane according to claim 1, wherein the reaction component of the polyurethane prepolymer A) further comprises component A3) which is a polymeric polyol different from the multifunctional polyether polyol.

5. The aqueous dispersion of polyurethane according to claim 4, wherein the component A3) is one or more selected from the group consisting of a polycarbonate polyol, a polyester polyol and a low-functional polyether polyol.

6. The aqueous dispersion of polyurethane according to claim 5, wherein the weight ratio of the multifunctional polyether polyol to the polycarbonate polyol is from 1:4 to 1:10.

7. The aqueous dispersion of polyurethane according to claim 5, wherein the weight ratio of the multifunctional polyether polyol to the polyester polyol is from 1:20 to 1:40.

8. The aqueous dispersion of polyurethane according to claim 1, wherein the polyisocyanate is selected from the group consisting of aliphatic polyisocyanates and alicyclic polyisocyanates.

9. The aqueous dispersion of polyurethane according to claim 8, wherein the alicyclic polyisocyanate is present in an amount of not less than 25% by weight, based on the amount of component Al) as 100% by weight.

10. The aqueous dispersion of polyurethane according to claim 8, wherein the alicyclic polyisocyanate comprises at least two alicyclic rings.

11. The aqueous dispersion of polyurethane according to claim 1, wherein the isocyanate-reactive component B) is an anionic hydrophilic agent or a potential anionic hydrophilic agent.

12. A method for preparing the aqueous dispersion of polyurethane according to claim 1, comprising the following steps: a. reacting component A1) with component A2) to produce the polyurethane prepolymer A); b. reacting said polyurethane prepolymer A) with the isocyanate-reactive component B) to produce a polyurethane polymer; and c. introducing water prior to, during or after step b to produce the aqueous dispersion of polyurethane.

13. A coating composition comprising the aqueous dispersion of polyurethane according to claim 1.

14. A coated product, comprising a substrate and a coating composition comprising the aqueous dispersion of polyurethane according to claim 1 applied thereon.

15. The coated product according to claim 14, wherein the substrate is selected from the group consisting of wood, plastic, metal, glass, fabric, leather, paper, glass fiber, polymer fiber and graphite fiber.

16. A method for preparing a coated product, comprising applying a coating composition comprising the aqueous dispersion of polyurethane according to claim 1 onto a substrate.

17. The aqueous dispersion of polyurethane according to claim 1, wherein the multifunctional polyether polyol has a functionality of 6.

18. The aqueous dispersion of polyurethane according to claim 1, wherein a molar ratio of isocyanate groups of the polyurethane prepolymer A) to isocyanate-reactive groups of the isocyanate-reactive component B) is from 1.05 to 3.5.

Description

EXAMPLES

(1) All percentages involved in the present invention are percent by weight, unless otherwise indicated.

(2) The analysis and measurement of the present invention were all made at 23° C., unless otherwise indicated.

(3) The number-average molecular weight according to the present invention was measured with a gel permeation chromatography at 23° C., using tetrahydrofuran as the mobile phase and polystyrene as the standard for calibration.

(4) The solid content of the aqueous dispersion of polyurethane was measured according to DIN-EN ISO 3251 using a HS153 moisture meter from Mettler Toledo Company.

(5) The content of isocyanate group (NCO) was measured by volume according to DIN-EN ISO 11909.

(6) The particle size of aqueous dispersion of polyurethane was measured using laser spectrometry (Zatasizer Nano ZS 3600 laser particle size analyzer from Malvern Instrument Company) after dilution with deionized water.

(7) The viscosity of aqueous dispersion of the aqueous dispersion of polyurethane was measured according to DIN 53019 at 23° C., using a rotational viscometer DV-II+Pro from Brookfield company.

(8) PH value was measured at 23° C. using a PB-10 pH meter from Sartorius Company, Germany.

(9) Water vapor transmission rate (WVTR) denotes the amount of water vapor permeating through a 1 m.sup.2 of fabric sample in 24 hours at a specific temperature under a specific relative humidity, with a specific water vapor pressure difference and a specific coat thickness, represented with a unit g/m.sup.2/24 h. WVTR was measured according to DS2109 TM1, using a water vapor transmission rate meter from British Textile Technology Group, Britain.

(10) Hydrostatic pressure is also called as hydrostatic head (HSH), denotes the water pressure capable of being supported by a unit area of fabric, with a unit mm. For example, a hydrostatic pressure of 5000 mm means that a unit area of fabric can support a maximum hydraulic pressure of 5 m without leakage. HSH was measured according to DIN EN20811:1992 at 20° C., using a hydrostatic pressure tester from PFAFF Company.

(11) Raw Materials and Reagents

(12) TABLE-US-00001 Desmodur ® H 1,6-hexamethylene diisocyanate, available from Covestro Deutschland AG, Germany, used as the polyisocyanate of component A1). Desmodur ® I Isophorone diisocyanate, available from Covestro Deutschland AG, Germany, used as the polyisocyanate of component A1). Desmodur ® W Dicyclohexyl methane diisocyanate, available from Covestro Deutschland AG, Germany, used as the polyisocyanate of component A1). Desmophen ® A polyether polyol based on polypropylene oxide and 3170 polyethylene oxide, having a functionality of 6, a number-average molecular weight of 3300 g/mol, and a content of oxyethylene group of 81 wt.-%, available from Covestro Deutschland AG, Germany, used as the multifunctional polyether polyol of component A2). Desmophen ® A polyether polyol based on polypropylene oxide and 41WB09 polyethylene oxide, having a functionality of 3, a number-average molecular weight of 4550 g/mol, and a content of oxyethylene group of 71 wt.-%, available from Covestro Deutschland AG, Germany, used as the multifunctional polyether polyol of component A2). Desmophen ® Polyester polyol, having an OH value of 66 mg PE170HN KOH/g and a number-average molecular weight of 1700 g/mol, available from Covestro Deutschland AG, Germany, used as component A3), the polymeric polyol different from the multifunctional polyether polyol. Desmophen ® Polycarbonate polyol of hexanediol and dimethyl C2200 carbonate, having an OH value of 56 mg KOH/g and a number-average molecular weight of 2000 g/mol, available from Covestro Deutschland AG, Germany, used as component A3), the polymeric polyol different from the multifunctional polyether polyol. Desmophen ® Polyether polyol with low functionality, having a L300 functionality of 2 and a number-average molecular weight of 2000 g/mol, available from Covestro Deutschland AG, Germany, used as component A3), the polymeric polyol different from the multifunctional polyether polyol. Desmophen ® Polyether polyol with low functionality, having a 3600 functionality of 2 and a number-average molecular weight of 2000 g/mol, available from Covestro Deutschland AG, Germany, used as component A3), the polymeric polyol different from the multifunctional polyether polyol. Desmophen ® Polypropylene oxide diol, having a functionality of 2 LP112 and a number-average molecular weight of 1000 g/mol, available from Covestro Deutschland AG, Germany, used as component A3), the polymeric polyol different from the multifunctional polyether polyol. LB25 Mono-functional polyether polyol based on ethylene oxide/propylene oxide, having a number-average molecular weight of 2250 g/mol, available from Covestro Co., Ltd, Germany, used as component A3), the polymeric polyol different from the multifunctional polyether polyol. DMPA 2,2-dihydroxymethyl malonic acid, available from Aldrich chemical reagent company, Germany, used as the isocyanate-reactive anionic hydrophilizing agent or potential anionic hydrophilizing agent of component A5). AAS Sodium diaminosulfonate, NH.sub.2—CH.sub.2CH.sub.2—NH—CH.sub.2CH.sub.2—SO.sub.3Na, at a concentration of 45% in water, available from Covestro Deutschland AG, Germany, used as the isocyanate-reactive component of component B). KV1386 Monosodium salt of N-(2-amino ethyl)-β-alanine, available from Covestro Deutschland AG, Germany, used as the isocyanate-reactive component of component B). EDA Ethylene diamine, available from Jiaxing Jinyan Chemical Co., Ltd., China, used as the amino functional compound of component C). IPDA Isophorone diamine, available from Covestro Deutschland AG, Germany, used as the amino functional compound of component C). Impranil ® Dispersion of anionic/non-ionic aliphatic DLU polycarbonate-polyether polyurethane, having a solid content of 60 wt.-%, available from Covestro Deutschland AG, Germany, used as the aqueous dispersion of polyurethane for comparative examples.

Example 1

(13) 371 g Desmophen® PE170HN and 7.5 g Desmophen® 3170 were heated to 65° C., and 105.66 g Desmodur® W was added to provide a mixture. The mixture was stirred at 120° C. until the actual NCO value of the mixture was less than the theoretical NCO value, providing a polyurethane prepolymer. The prepolymer was dissolved at 40° C. with 860.8 g acetone, and then a solution of 61.7 g AAS and 168.94 g water was metered in. After stirring for 15 minutes, 885.1 g water was added for dispersion, and the solvent was removed through vacuum distillation to provide an aqueous dispersion of polyurethane. The aqueous dispersion of polyurethane had a solid content of 33.14%, a particle size of 108.3 nm, a viscosity of 98 mPa.Math.s and a pH of 7.73.

Example 2

(14) 168.2 g Desmophen® C2200, 19.2 g Desmophen® L300, 53.2 g Desmophen® 3600, 77.6 g LB25, 5 g DMPA and 29.3 g Desmophen® 3170 were heated at 100° C. for 1 h, followed by cooling to 75° C. 54.3 g Desmodur® W and 34.8 g Desmodur® H were added to provide a mixture, and the mixture was stirred at 100-110° C. until the actual NCO value of the mixture was less than the theoretical NCO value, providing a polyurethane prepolymer. The prepolymer was dissolved at 80° C. with 797.4 g acetone, followed by cooling to 40° C. Then, a solution of 11.5 g DEA (available from Aldrich chemical reagent company, Germany), 3.3 g EDA and 108.3 g water were metered in. After stirring at 40° C. for 30 minutes, 972.8 g water was added for dispersion, and the solvent was removed through vacuum distillation to provide an aqueous dispersion of polyurethane. The aqueous dispersion of polyurethane had a solid content of 30.7%, a particle size of 57.9 nm, a viscosity of 926 mPa.Math.s and a pH of 5.9.

Example 3

(15) 168.2 g Desmophen® C2200, 36.5 g Desmophen® L300, 53.2 g Desmophen® 3600, 77.6 g LB25, 5 g DMPA and 22.3 g Desmophen® 3170 were heated at 100° C. for 1 h, followed by cooling to 75° C. 54.3 g Desmodur® W and 34.8 g Desmodur® H were added to provide a mixture, and the mixture was stirred at 100-110° C. until the actual NCO value of the mixture was less than the theoretical NCO value, providing a polyurethane prepolymer. The prepolymer was dissolved at 80° C. with 785.7 g acetone, followed by cooling to 40° C. Then, a solution of 11.5 g DEA, 3.3 g EDA and 108.3 g water were metered in. After stirring at 40° C. for 30 minutes, 957.4 g water was added for dispersion, and the solvent was removed through vacuum distillation to provide an aqueous dispersion of polyurethane. The aqueous dispersion of polyurethane had a solid content of 30.4%, a particle size of 48.2 nm, a viscosity of 250 mPa.Math.s and a pH of 5.9.

Example 4

(16) 168.2 g Desmophen® C2200, 19.2 g Desmophen® L300, 40 g Desmophen® 3600, 6.6 g Desmophen® LP112, 77.6 g LB25, 5 g DMPA and 22.3 g Desmophen® 3170 were heated at 100° C. for 1 h, followed by cooling to 75° C. 54.3 g Desmodur® W and 34.8 g Desmodur® H were added to provide a mixture, and the mixture was stirred at 100-110° C. until the actual NCO value of the mixture was less than the theoretical NCO value, providing a polyurethane prepolymer. The prepolymer was dissolved at 80° C. with 785.7 g acetone, followed by cooling to 40° C. Then, a solution of 11.5 g DEA, 4.5 g EDA and 116.9 g water were metered in. After stirring at 40° C. for 30 minutes, 951.5 g water was added for dispersion, and the solvent was removed through vacuum distillation to provide an aqueous dispersion of polyurethane. The aqueous dispersion of polyurethane had a solid content of 30.5%, a particle size of 84.9 nm, a viscosity of 2467 mPa.Math.s and a pH of 5.8.

Example 5

(17) 168.2 g Desmophen® C2200, 19.2 g Desmophen® L300, 53.2 g Desmophen® 3600, 77.6 g LB25, 5 g DMPA and 29.3 g Desmophen® 3170 were heated at 100° C. for 1 h, followed by cooling to 75° C. 108.5 g Desmodur® W was added to provide a mixture, and the mixture was stirred at 100-110° C. until the actual NCO value of the mixture was less than the theoretical NCO value, providing a polyurethane prepolymer. The prepolymer was dissolved at 80° C. with 832 g acetone, followed by cooling to 40° C. Then, a solution of 11.5 g DEA, 3.3 g EDA and 108.3 g water were metered in. After stirring at 40° C. for 30 minutes, 1018 g water was added for dispersion, and the solvent was removed through vacuum distillation to provide an aqueous dispersion of polyurethane. The aqueous dispersion of polyurethane had a solid content of 30.2%, a particle size of 45.3 nm, a viscosity of 69 mPa.Math.s and a pH of 6.1.

Example 6

(18) 168.2 g Desmophen® C2200, 53.2 g Desmophen® 3600, 77.6 g LB25, 5 g DMPA and 29.3 g Desmophen® 3170 were heated at 100° C. for 1 h, followed by cooling to 75° C. 27.13 g Desmodur® W and 52.18 g Desmodur® H were added to provide a mixture, and the mixture was stirred at 100-110° C. until the actual NCO value of the mixture was less than the theoretical NCO value, providing a polyurethane prepolymer. The prepolymer was dissolved at 80° C. with 746 g acetone, followed by cooling to 40° C. Then, a solution of 11.5 g DEA, 3.3 g EDA and 108.3 g water were metered in. After stirring at 40° C. for 30 minutes, 902.3 g water was added for dispersion, and the solvent was removed through vacuum distillation to provide an aqueous dispersion of polyurethane. The aqueous dispersion of polyurethane had a solid content of 30.3%, a particle size of 84.2 nm, a viscosity of 1552 mPa.Math.s and a pH of 6.1.

Example 7

(19) 168.2 g Desmophen® C2200, 53.2 g Desmophen® 3600, 77.6 g LB25, 5 g DMPA and 29.3 g Desmophen® 3170 were heated at 100° C. for 1 h, followed by cooling to 75° C. 54.3 g Desmodur® W and 34.8 g Desmodur® H were added to provide a mixture, and the mixture was stirred at 100-110° C. until the actual NCO value of the mixture was less than the theoretical NCO value, providing a polyurethane prepolymer. The prepolymer was dissolved at 80° C. with 763 g acetone, followed by cooling to 40° C. Then, a solution of 11.5 g DEA, 3.3 g EDA and 108.3 g water were metered in. After stirring at 40° C. for 30 minutes, 905.3 g water was added for dispersion, and the solvent was removed through vacuum distillation to provide an aqueous dispersion of polyurethane. The aqueous dispersion of polyurethane had a solid content of 30.7%, a particle size of 131.2 nm, a viscosity of 712 mPa.Math.s and a pH of 6.2.

Example 8

(20) 168.2 g Desmophen® C2200, 53.2 g Desmophen® 3600, 77.6 g LB25, 5 g DMPA and 29.3 g Desmophen® 3170 were heated at 100° C. for 1 h, followed by cooling to 75° C. 108.5 g Desmodur® W was added to provide a mixture, and the mixture was stirred at 100-110° C. until the actual NCO value of the mixture was less than the theoretical NCO value, providing a polyurethane prepolymer. The prepolymer was dissolved at 80° C. with 797.9 g acetone, followed by cooling to 40° C. Then, a solution of 11.5 g DEA, 3.3 g EDA and 108.3 g water were metered in. After stirring at 40° C. for 30 minutes, 973.5 g water was added for dispersion, and the solvent was removed through vacuum distillation to provide an aqueous dispersion of polyurethane. The aqueous dispersion of polyurethane had a solid content of 30.5%, a particle size of 57.5 nm, a viscosity of 68.8 mPa.Math.s and a pH of 6.1.

Example 9

(21) 168.2 g Desmophen® C2200, 53.2 g Desmophen® 3600, 77.6 g LB25, 5 g DMPA and 41.9 g Desmophen® 3170 were heated at 100° C. for 1 h, followed by cooling to 75° C. 27.13 g Desmodur® W and 52.18 g Desmodur® H were added to provide a mixture, and the mixture was stirred at 100-110° C. until the actual NCO value of the mixture was less than the theoretical NCO value, providing a polyurethane prepolymer. The prepolymer was dissolved at 80° C. with 755 g acetone, followed by cooling to 40° C. Then, a solution of 11.5 g DEA, 3.3 g EDA and 108.3 g water were metered in. After stirring at 40° C. for 30 minutes, 918 g water was added for dispersion, and the solvent was removed through vacuum distillation to provide an aqueous dispersion of polyurethane. The aqueous dispersion of polyurethane had a solid content of 30.4%, a particle size of 108.9 nm, a viscosity of 2315 mPa.Math.s and a pH of 6.1.

Example 10

(22) 363.4 g Desmophen® PE170HN and 7.2 g Desmophen® 41WB09 were heated to 65° C., and 105.66 g Desmodur® W was added to provide a mixture. The mixture was stirred at 120° C. until the actual NCO value of the mixture was less than the theoretical NCO value, providing a polyurethane prepolymer. The prepolymer was dissolved at 40° C. with 846.8 g acetone, and then a solution of 61.7 g AAS and 169.7 g water was metered in. After stirring for 15 minutes, 722.1 g water was added for dispersion, and the solvent was removed through vacuum distillation to provide an aqueous dispersion of polyurethane. The aqueous dispersion of polyurethane had a solid content of 34.03%, a particle size of 134.8 nm, a viscosity of 2079 mPa.Math.s and a pH of 8.1.

Comparative Example 1

(23) 595.0 g Desmophen® PE170HN was heated to 65° C., and 164.3 g Desmodur® W was added to provide a mixture. The mixture was stirred at 120° C. until the actual NCO value of the mixture was less than the theoretical NCO value, providing a polyurethane prepolymer. The prepolymer was dissolved at 40° C. with 1349.98 g acetone, and then a solution of 96 g AAS and 168.9 g water was metered in. After stirring for 15 minutes, 1404.5 g water was added for dispersion, and the solvent was removed through vacuum distillation to provide an aqueous dispersion of polyurethane. The aqueous dispersion of polyurethane had a solid content of 37.9%, a particle size of 149 nm, a viscosity of 421 mPa.Math.s and a pH of 9.45.

Comparative Example 2

(24) 382.5 g Desmophen® PE170HN was heated to 65° C., and 105.66 g Desmodur® W was added to provide a mixture. The mixture was stirred at 125-130° C. until the actual NCO value of the mixture was less than the theoretical NCO value, providing a polyurethane prepolymer. The prepolymer was dissolved at 40° C. with 867.8 g acetone, and then a solution of 61.7 g AAS and 111.86 g water was metered in. After stirring for 15 minutes, 628.1 g water was added for dispersion, and the solvent was removed through vacuum distillation to provide an aqueous dispersion of polyurethane. The aqueous dispersion of polyurethane had a solid content of 41.57%, a particle size of 107.6 nm, a viscosity of 2851 mPa.Math.s and a pH of 8.54.

Comparative Example 3

(25) 318.75 g Desmophen® PE170HN was heated to 65° C., and 87.9 g Desmodur® W was added to provide a mixture. The mixture was stirred at 120° C. until the actual NCO value of the mixture was less than the theoretical NCO value, providing a polyurethane prepolymer. The prepolymer was dissolved at 40° C. with 722.9 g acetone, and then a solution of 32.9 g AAS, 1.6 g EDA and 102.1 g water was metered in. After stirring for 15 minutes, 514.4 g water was added for dispersion, and the solvent was removed through vacuum distillation to provide an aqueous dispersion of polyurethane. The aqueous dispersion of polyurethane had a solid content of 40.0%, a particle size of 116.2 nm, a viscosity of 58 mPa.Math.s and a pH of 7.4.

Comparative Example 4

(26) 382.5 g Desmophen® PE170HN was heated to 65° C., and 105.66 g Desmodur® W was added to provide a mixture. The mixture was stirred at 125-130° C. until the actual NCO value of the mixture was less than the theoretical NCO value, providing a polyurethane prepolymer. The prepolymer was dissolved at 40° C. with 867.8 g acetone, and then a solution of 48 g KV1386 and 144 g water was metered in. After stirring for 15 minutes, 588.2 g water was added for dispersion, and the solvent was removed through vacuum distillation to provide an aqueous dispersion of polyurethane. The aqueous dispersion of polyurethane had a solid content of 41.24%, a particle size of 207.8 nm, a viscosity of 28 mPa.Math.s and a pH of 7.75.

Comparative Example 5

(27) 168.2 g Desmophen® C2200, 38.35 g Desmophen® L300, 53.2 g Desmophen® 3600, 77.6 g LB25 and 5 g DMPA were heated to 75° C. 69.58 g Desmodur® H was added to provide a mixture. The mixture was stirred at 100° C. until the actual NCO value of the mixture was less than the theoretical NCO value, providing a polyurethane prepolymer. The prepolymer was dissolved at 40° C. with 732.37 g acetone, and then a solution of 11.5 g DEA, 3.28 g EDA and 108.3 g water was metered in. After stirring for 30 minutes, 887.4 g water was added for dispersion, and the solvent was removed through vacuum distillation to provide an aqueous dispersion of polyurethane. The aqueous dispersion of polyurethane had a solid content of 31.1%, a particle size of 344.1 nm, a viscosity of 174 mPa.Math.s and a pH of 6.23.

Comparative Example 6

(28) 168.2 g Desmophen® C2200, 38.35 g Desmophen® L300, 53.2 g Desmophen® 3600, 77.6 g LB25 and 5 g DMPA were heated at 100° C. for 1 h, followed by cooling to 75° C. 54.3 g Desmodur® W and 34.8 g Desmodur® H were added to provide a mixture. The mixture was stirred at 100-110° C. until the actual NCO value of the mixture was less than the theoretical NCO value, providing a polyurethane prepolymer. The prepolymer was dissolved at 80° C. with 767 g acetone, followed by cooling to 40° C. Then, a solution of 11.5 g DEA, 3.3 g EDA and 108.3 g water were metered in. After stirring at 40° C. for 30 minutes, 932.8 g water was added for dispersion, and the solvent was removed through vacuum distillation to provide an aqueous dispersion of polyurethane. The aqueous dispersion of polyurethane had a solid content of 30.3%, a particle size of 55.1 nm, a viscosity of 92 mPa.Math.s and a pH of 6.0.

(29) Property Testing

(30) Preparation of Coat

(31) Release paper was placed in front of the back roll in a film stretching device composed of two polishing rolls (where the spacing between the two rolls can be adjusted precisely). A clearance gauge was used to adjust the distance between the paper and the front roll. The distance corresponded to the film thickness of the coat (wet) obtained, and could be adjusted pursuant to the thickness required for each coating. A plurality of coatings could also be coated continuously.

(32) The viscosity of the aqueous dispersions of polyurethane obtained from the examples and comparative examples was each adjusted to 4500 mPa.Math.s (adjusted through Borchi Gel ALA). The aqueous dispersion of polyurethane was poured into the clearance between the paper and the front roll, and the release paper was pulled down vertically so as to form a coat on the paper. If several coats were to be coated, then, after drying of one coat, the release paper was reinserted into the device, followed by the coating of another coat.

(33) Test of Water Vapor Transmission Rate (WVTR)

(34) A wet coat with 500 microns was coated onto a VEZ matt release paper, the wet coat being dried at 50° C. for 10 minutes, followed by drying at 150° C. for 3 minutes, and the water vapor transmission rate (WVTR) of the coat being measured, with the results being provided in Table 1.

(35) Hydrostatic Head (HSH) Test

(36) A coat having strength of 37.4 g/cm.sup.2 was prepared according to DIN 53886. A wet coat with 500 microns was coated onto a VEZ matt release paper, and the wet coating was dried at 50° C. for 10 minutes, followed by drying at 150° C. for 3 minutes. The hydrostatic head value of the coat was tested, with the results being provided in Table 1.

(37) TABLE-US-00002 TABLE 1 Water Vapor Transmission Rate and Hydrostatic Head of the Coats Formed in the Examples and Comparative Examples of the Invention Water Vapor Transmission Hydrostatic Head Rate (WVTR) (g/m.sup.2/24 h) (HSH) (mm) Comparative Example 1 16559 >4000 Comparative Example 2 7230 >7000 Comparative Example 3 4001 6500 Comparative Example 4 9407 >7000 Comparative Example 5 21723 3000 Comparative Example 6 N/A N/A Comparative Example 7 1487 >7500 (Impranil ® DLU) Example 1 19090 >7000 Example 2 13261 >7000 Example 3 12702 >7500 Example 4 12468 >8000 Example 5 18622 >7000 Example 6 10533 >7000 Example 7 11889 >7500 N/A: coatings are unable to form films, and thus it is impossible to get the values of water vapor transmission rate or hydrostatic head.

(38) The higher the water vapor transmission rate was, the better the moisture permeability of the waterproof and moisture permeable fabric was. The higher the hydrostatic head value was, the better the waterproof of the waterproof and moisture permeable fabric was. In the field of textile industry, it was generally required that the water vapor transmission rate and hydrostatic head of a waterproof and moisture permeable fabric were at least higher than 5000 g/m.sup.2/24 h and 5000 mm, respectively. From Table 1, the coat formed by the aqueous dispersion of polyurethane according to comparative examples either could not balance the water vapor transmission rate and hydrostatic head, or the water vapor transmission rate and hydrostatic head were not high enough. The coat formed by the aqueous dispersion of polyurethane according to the inventive examples not only could balance the water vapor transmission rate and hydrostatic head, but also resulted in water vapor transmission rate and hydrostatic head much higher than those of the comparative examples. It thus could be concluded that the waterproof and moisture permeability of the coat formed by the aqueous dispersion of polyurethane according to the inventive examples were much better than those of the comparative examples.

(39) Washing Resistance Test

(40) The fabric obtained by coating with the aqueous dispersion of polyurethane according to the inventive examples or comparative examples was tested for washing resistance. The coated fabric was water washed at 30° C. for 35 minutes, then dried at room temperature. The water washing and drying steps were repeated once, which process was called as one time of water washing. WVTR and HSH values of the coat of the coated fabric were measured after water washing the coated fabric three or ten times. WVTR and HSH values of the coat of the coated fabric obtained from coating the aqueous dispersion of polyurethane according to the inventive examples and comparative examples prior to and after water washing were listed in Table 2.

(41) TABLE-US-00003 TABLE 2 The values of WVTR and HSH prior to and after washing the Fabric Coat Obtained by the coating of the Examples and Comparative Examples of the Invention prior to after washing after washing washing three times ten times WVTR HSH WVTR HSH WVTR HSH (g/m.sup.2/24 h) (mm) (g/m.sup.2/24 h) (mm) (g/m.sup.2/24 h) (mm) Comparative 7230 >7000 9264 1000 — — Example 2 Comparative 9407 >7000 296 7000 — — Example 4 Comparative 1487 >7500 1019 >7000 — — Example 7 (Impranil ® DLU) Example 2 13261 >7000 7411 >7000 8372 >7000 Example 3 12702 >7500 6039 >7000 — — Example 4 12468 >8000 7230 >7000 — — Example 6 10533 >7000 6088 7000 7715 >7500 Double 7148 >7000 6778 >7000 9087 >7000 coating (the lower coating is Example 1; the upper coating is Example 6)

(42) It could be seen from Table 2 that, both the WVTR and HSH values of the coat of the coated fabric obtained from the aqueous dispersion of polyurethane according the comparative examples were significantly less than 5000 after water washing three times, which could not satisfy the requirement by the art on the waterproof and moisture permeability of a waterproof and moisture permeable fabric, representing a poor washing resistance of the waterproof and moisture permeable fabric. The coat of the coated fabric obtained from the aqueous dispersion of polyurethane according to the inventive examples showed a WVTR value higher than 5000 g/m.sup.2/24 h and a HSH value higher than 5000 mm after water washing three or ten times, which meant that the fabric still satisfied the requirement by the art on waterproof and moisture permeability of a waterproof and moisture permeable fabric even after water washing three or ten times, representing a good water-washing resistance of the waterproof and moisture permeable fabric.

(43) Those skilled in the art can understand easily that the present invention is not restricted by the details discussed above, while the present invention can be carried out in other special forms without departing the spirit or prominent characters of the present invention. Therefore, interpreted in any views, the Examples of the invention are provided exemplarily without any restriction, such that the range of the invention is defined by the claims instead of the detailed discussion above; and accordingly, any modification, as long as it falls within an interpretation and range defined thereby equivalent to the claims, should be deemed as a part of the invention.