POLYURETHANE-UREA DISPERSIONS BASED ON POLYCARBONATE-POLYOLS AS COATING COMPOSITIONS

Abstract

The present invention relates to an aqueous polyurethane-urea dispersion comprising at least one polyurethane-urea made of (A1) at least one polyisocyanate, (A2) at least one polycarbonate polyol having a heat flow below 3 J/g in the first circle of DSC testing from 20 to 100° C. according to testing method DIN 65467-1999, (A3) optionally, at least one polyether polyol with an OH functionality of 1.8 to 2.2, preferably 2.0, (A4) optionally, at least one compound having a molecular weight of 62 to 400 g/mol and possessing in total two or more hydroxyl and/or amino groups, (A5) optionally, at least one isocyanate-reactive nonionically hydrophilicizing compound, (A6) optionally, at least one isocyanate-reactive, ionically, or potentially ionically, hydrophilicizing compound, (A7) optionally, at least one neutralizing reagents, (A8) optionally, at least one additive, to a process for the preparation of sais aqueous polyurethane-urea dispersion, and to its use as a coating composition.

Claims

1. An aqueous polyurethane-urea dispersion comprising at least one polyurethane-urea made of: (A1) at least one polyisocyanate, (A2) at least one polycarbonate polyol having a heat flow below 3 J/g in a first cycle of DSC testing from 20 to 100° C. according to testing method DIN 65467-1999, (A3) optionally, at least one polyether polyol with an OH functionality of 1.8 to 2.2, (A4) optionally, at least one compound having a molecular weight of 62 to 400 g/mol and possessing in total two or more hydroxyl and/or amino groups, (A5) optionally, at least one isocyanate-reactive nonionically hydrophilicizing compound, (A6) optionally, at least one isocyanate-reactive, ionically, or potentially ionically, hydrophilicizing compound, (A7) optionally, at least one neutralizing reagents, (A8) optionally, at least one additive.

2. The aqueous polyurethane dispersion according to claim 1, wherein component A2 has a number-average molecular weight of 1000 to 3000 g/mol.

3. The aqueous polyurethane dispersion according to claim 1, wherein component A2 has a hydroxyl number of 112 to 56 mg KOH/g.

4. The aqueous polyurethane dispersion according to claim 1, wherein component A2 has an OH functionality of 1.8 to 2.2.

5. The aqueous polyurethane dispersion according to claim 1, wherein components A1 to A8 are present in the following amounts: (A1) 15 to 25% by weight, (A2) 15 to 67.5% by weight, (A3) 0 to 65% by weight, (A4) 0 to 5.5% by weight, (A5) 0 to 5.0% by weight, (A6) 0 to 2.5% by weight, (A7) 0 to 2.0% by weight, (A8) 0 to 3% by weight, wherein a sum of the amounts of (A1) to (A8) is 100% by weight of the at least one polyurethane-urea.

6. The aqueous dispersion according to claim 1, wherein a solids content of the polyurethane-urea dispersions is from 10 to 70% by weight based on a total weight of the polyurethane-urea dispersion.

7. The aqueous dispersion according to claim 1, wherein component (A1) comprises polyisocyanates or polyisocyanate blends based on 1,6-diisocyanatohexane, I-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl cyclohexane, 4,4′-diisocyanatodicyclohexyl methane, or a combination thereof.

8. The aqueous dispersion of claim 1, wherein component (A2) comprises polycarbonate polyols based on diols selected from the group consisting of 1,5-pentanediol, 1,6-hexanediol, and mixtures thereof.

9. The aqueous dispersion according to claim 8, wherein the diols comprise a mixture of 1,5-pentanediol and 1,6-hexandiol at a ratio of 35:65 to 50:50.

10. The aqueous dispersion according to claim 1, wherein component A3 is polytetrahydrofurane.

11. A process for the preparation of an aqueous polyurethane-urea dispersion according to claim 1, comprising: reacting components (A1), (A2) and optionally components (A3), (A4), (A5), (A6) and (A7) to form a polyurethane prepolymer; dispersing the polyurethane prepolymer in or by addition of water; and optionally reacting with or addition of (A8).

12. The process according to claim 11, wherein an NCO/OH ratio in preparation of the polyurethane prepolymer is 1.2/1 to 2.8/1.

13. A coating composition, comprising an aqueous polyurethane dispersion according to claim 1.

14. The coating composition according to claim 13, wherein the coating composition is applied to a woven or nonwoven textiles, leather, paper, hard fibre, straw, papery materials wood, glass, plastic, ceramic, stone, concrete, bitumen, porcelain, metal, or glass fibre.

Description

EXAMPLES

[0117] Test Methods:

[0118] All quantitative data, proportions and percentages, unless otherwise specified, are based on the weight and the total quantity of on the total weight of the compositions.

[0119] Unless stated otherwise, all analytical measurements refer to measurements at a temperature of 23° C.

[0120] NCO contents were determined volumetrically in accordance with DIN-EN ISO 11909-1998, unless expressly mentioned otherwise.

[0121] The solid contents were determined with a moisture analyzer (instrument: Mettler Toledo HS153, Metter-Toledo Instruments Co., Ltd.).

[0122] pH values of the PU dispersions were determined using a pH meter (instrument: Sartorius pH meter PB-10, Sartorius Scientific Instruments (Beijing) Co., Ltd.).

[0123] The average particle sizes (the number average is stated) of the PU dispersions were determined using laser correlation spectroscopy (instrument: Malvern Zetasizer Nano ZS 3600, Malvern Instr. Limited).

[0124] The viscosities given were determined by rotational viscometry in accordance with DIN 53019-1-2008 at 23° C. with a rotational viscometer (instrument: Brookfield DV-II+ Pro, Ametek Commercial Enterprise (Shanghai) Co., Ltd.).

[0125] The physical properties of coating films based on the polyurethane-urea dispersions were determined on free films produced as follows:

[0126] To determine tensile and elongation, free films are prepared. To do this, a thickener (here, Borchi Gel ALA) is used to thicken PUDs in such a way that the coating just remains free-flowing. The quantity of thickener is based on the PUDs initial viscosity. An applicator is then used to apply the thickened PUDs with a 300 to 500 μm wet film thickness onto the backing paper. After a flash-off time of around 15 minutes, drying is performed as follows: 1.5 hours at 50° C.; 30 minutes at 70° C.; 3 minutes at 150° C. After forced drying and one day of storage at room temperature, the coating film is removed from the backing paper, and 3 to 5 test specimens are punched out using a punch.

[0127] The tensile test is based on DIN 53504-1994, which is performed in a standard atmosphere, 23° C. and 50% rel. humidity using a tensile testing device. The test specimens are in strip or dumbbell form. The film thickness should be as uniform as possible and not exhibit any holes, bubbles or cracks. Elongation at break in %, tensile strength in N/mm.sup.2, and 100% modulus in N/mm.sup.2 were determined according to DIN 53504-1994.

[0128] Substances and Abbreviations Used:

[0129] Desmophen C 2200: Polycarbonate based on 1,6-hexanediol, OH number 56, molecular weight 2000 g/mol, Covestro Deutschland AG, Leverkusen

[0130] Desmophen C 2613: Polycarbonate based on 1,4-butanol and 1,6-hexanediol, OH number 56, molecular weight 2000 g/mol, Covestro Deutschland AG, Leverkusen

[0131] Desmophen C 3200: Polycarbonate based on 1,5-pentyl glycol and 1,6-hexanediol, OH number 56, molecular weight 2000 g/mol, Covestro Deutschland AG, Leverkusen

[0132] Desmophen C 3100: Polycarbonate based on 1,5-pentyl glycol and 1,6-hexanediol, OH number 112, molecular weight 1000 g/mol, Covestro Deutschland AG, Leverkusen

[0133] PolyTHF 1000: Polytetramethylene glycol polyol, OH number 112, molecular weight=1000 g/mol., BASF Chemicals CO., Ltd.

[0134] PolyTHF 2000: Polytetramethylene glycol polyol, OH number 56, molecular weight 2000 g/mol, BASF Chemicals CO., Ltd.

[0135] Desmophen 3600: Polypropylene oxide polyether, OH number 56, molecular weight 2000 g/mol, Covestro Deutschland AG, Leverkusen

[0136] Polyether LB 25: Monofunctional polyethylene glycol, OH number 25, molecular weight 2250 g/mol, Covestro Deutschland AG, Leverkusen

[0137] Desmophen 1652: Polyester based on adipic acid, monoethyleneglycol, 1,4-butanediol, and diethyleneglycol, OH number 53, molecular weight 2100 g/mol, Covestro Polymers (China) Co., Ltd., Shanghai

[0138] PE 170 HN: Polyester based on adipic acid, neopentyl glycol and 1,6-hexanediol, OH number 66, molecular weight 1700 g/mol, Covestro Polymers (China) Co., Ltd., Shanghai

[0139] Desmodur I: 3-isocyanatomethyl-3,5,5-trimethyl cyclohexyl isocyanate, NCO content 37.8%, molecular weight 222 g/mol, Covestro Polymers (China) Co., Ltd.

[0140] Desmodur H: 1,6-Hexamethylene Diisocyanate, NCO content 50%, molecular weight 168 g/mol, Covestro Polymers (China) Co., Ltd.

[0141] Desmodur W: dicyclohexylmethane-4,4′-diisocyanate, molecular weight 262 g/mol, Covestro Polymers (China) Co., Ltd.

[0142] Neopentylglycol: molecular weight 104 g/mol, Sigma-Aldrich (Shanghai) Trading Co., Ltd

[0143] Baybond VP LS 2387: Diaminosulfonate, 45% by weight in water, amine number 266, molecular weight 422 g/mol, Covestro Deutschland AG, Leverkusen

[0144] KV 1386: Diaminocarbonate, 40% in water, amine number 244, molecular weight 387.88 g/mol, Covestro Deutschland AG, Leverkusen

[0145] Hydrazine Hydrate 64% in water, molecular weight 50.06 as supplied, Sigma-Aldrich (Shanghai) Trading Co., Ltd

[0146] IPDA: 3-aminomethyl-3,5,5-trimethylcyclohexyl amine, molecular weight 170.3 as supplied, Sigma-Aldrich (Shanghai) Trading Co., Ltd

[0147] Diethylenetriamine: molecular weight 103 g/mol, Sigma-Aldrich (Shanghai) Trading Co., Ltd

[0148] Trimethylamine: molecular weight 101 g/mol, Sigma-Aldrich (Shanghai) Trading Co., Ltd

[0149] Carbohydrazide: molecular weight 90.08 g/mol, as supplied, Sigma-Aldrich (Shanghai) Trading Co., Ltd

[0150] KOH: molecular weight 56.00 g/mol, as supplied, Sigma-Aldrich (Shanghai) Trading Co., Ltd

Example 1.1 (According to the Invention)

[0151] The mixture of 155.5 g of Desmophen C 3200, 198.6 g of PTHF 2000, 86.55 g of PTHF 1000 and 16.2 g of Polyether LB 25 was combined with 58.69 g of Desmodur I and 49.00 g of Desmodur H at 70° C., heated up to 120° C. and stirred at 120° C. until a constant NCO value of 3.31% by weight was achieved. The prepolymer was dissolved with 1259.62 g of acetone below 90° C. and stirred for 20 minutes. A mixture of 1.23 g of hydrazine Hydrate, 13.20 g of diaminosulfonate and 52.65 g of water was added at 40° C. within 5 minutes and stirred for 20 minutes. A mixture of 20.81 g of IPDA and 100.59 g of water was added at 40° C. within 8 minutes. 255.7 g of water was added at 40° C. within 15 minutes and mixed for 5 minutes before acetone was distilled. The final dispersion was filtered through 260 micron filter.

[0152] Dispersion with a solid content of 60.48% by weight, viscosity of 839.8 cps at 23° C., pH of 7.11, and mean particle size of 369.3 nm was obtained.

Example 1.2 (According to the Invention)

[0153] The mixture of 97.75 g of Desmophen C 3100, 198.6 g of PTHF 2000, 86.55 g of PTHF 1000 and 16.2 g of Polyether LB 25 was combined with 58.69 g of Desmodur I and 49.00 g of Desmodur H at 70° C., heated up to 120° C. and stirred at 120° C. until a constant NCO value of 4.36% by weight was achieved. The prepolymer was dissolved with 1085.43 g of acetone below 90° C. and stirred for 20 minutes. A mixture of 1.23 g of hydrazine Hydrate, 13.20 g of diaminosulfonate and 52.65 g of water was added at 40° C. within 5 minutes and stirred for 20 minutes. A mixture of 20.81 g of IPDA and 130.59 g of water was added at 40° C. within 8 minutes. 197.2 g of water was added at 40° C. within 15 minutes and mixed for 5 minutes before acetone was distilled. The final dispersion was filtered through 260 micron filter.

[0154] Dispersion with a solid content of 61.21% by weight, viscosity of 1456 cps at 23° C., pH of 7.72, and mean particle size of 846.6 nm was obtained.

Example 2.1 (According to the Invention)

[0155] The mixture of 137.95 g of Desmophen C 3200, 225.74 g of PTHF 2000, 101.29 g of Desmophen 3600, 1.72 g of DMPA and 14.58 g of Polyether LB 25 was combined with 50.42 g of Desmodur I and 39.5 g of Desmodur H at 70° C., heated up to 120° C. and stirred at 120° C. until a constant NCO value of 2.32% by weight was achieved. The prepolymer was dissolved with 1183.49 g of acetone below 90° C. and stirred for 20 minutes. 5.37 g of 10 wt. % KOH solution in water was added at 40° C. and stirred for 10 minutes. A mixture of 30.12 g of 10 wt. % carbohydrazide solution in water, 12.27 g of KV 1386 and 21.15 g of water was added at 40° C. within 5 minutes and stirred for 20 minutes. A mixture of 19.23 g of IPDA and 117.53 g of water was added at 40° C. within 8 minutes. 255.7 g of water was added at 40° C. within 15 minutes and mixed for 5 minutes before acetone was distilled. The final dispersion was filtered through 260 micron filter.

[0156] Dispersion with a solid content of 51.29% by weight, viscosity of 348.9 cps at 23° C., pH of 7.2, and mean particle size of 205.7 nm was obtained.

Comparative Example 1.1

[0157] The mixture of 155.5 g of Desmophen C 2200, 198.6 g of PTHF 2000, 86.55 g of PTHF 1000 and 16.2 g of Polyether LB 25 was combined with 58.69 g of Desmodur I and 49.00 g of Desmodur H at 70° C., heated up to 120° C. and stirred at 120° C. until a constant NCO value of 3.29% by weight was achieved. The prepolymer was dissolved with 1259.62 g of acetone below 90° C. and stirred for 20 minutes. A mixture of 1.23 g of hydrazine Hydrate, 13.20 g of diaminosulfonate and 52.65 g of water was added at 40° C. within 5 minutes and stirred for 20 minutes. A mixture of 20.81 g of IPDA and 130.59 g of water was added at 40° C. within 8 minutes. 255.7 g of water was added at 40° C. within 15 minutes and mixed for 5 minutes before acetone was distilled. The final dispersion was filtered through 260 micron filter.

[0158] Dispersion with a solid content of 62.96% by weight, viscosity of 1740 cps at 23° C., pH of 8.48, and mean particle size of 482.7 nm was obtained.

Comparative Example 1.2

[0159] The mixture of 155.5 g of Desmophen C 2613, 198.6 g of PTHF 2000, 86.55 g of PTHF 1000 and 16.2 g of Polyether LB 25 was combined with 58.69 g of Desmodur I and 49.00 g of Desmodur H at 70° C., heated up to 120° C. and stirred at 120° C. until a constant NCO value of 3.24% by weight was achieved. The prepolymer was dissolved with 1259.62 g of acetone below 90° C. and stirred for 20 minutes. A mixture of 1.23 g of hydrazine Hydrate, 13.20 g of diaminosulfonate and 52.65 g of water was added at 40° C. within 5 minutes and stirred for 20 minutes. A mixture of 20.81 g of IPDA and 130.59 g of water was added at 40° C. within 8 minutes. 255.7 g of water was added at 40° C. within 15 minutes and mixed for 5 minutes before acetone was distilled. The final dispersion was filtered through 260 micron filter.

[0160] Dispersion with a solid content of 60.53% by weight, viscosity of 2399 cps at 23° C., pH of 6.83, and mean particle size of 260.1 nm was obtained.

Comparative Example 1.3

[0161] The mixture of 133.18 g of PE 170 HN, 198.6 g of PTHF 2000, 86.55 g of PTHF 1000 and 16.2 g of Polyether LB 25 was combined with 58.69 g of Desmodur I and 49.00 g of Desmodur H at 70° C., heated up to 120° C. and stirred at 120° C. until a constant NCO value of 3.62% by weight was achieved. The prepolymer was dissolved with 1207.36 g of acetone below 90° C. and stirred for 20 minutes. A mixture of 1.23 g of hydrazine Hydrate, 13.20 g of diaminosulfonate and 52.65 g of water was added at 40° C. within 5 minutes and stirred for 20 minutes. A mixture of 20.81 g of IPDA and 130.59 g of water was added at 40° C. within 8 minutes. 238.1 g of water was added at 40° C. within 15 minutes and mixed for 5 minutes before acetone was distilled. The final dispersion was filtered through 260 micron filter.

[0162] Dispersion with a solid content of 59.18% by weight, viscosity of 1284 cps at 23° C., pH of 7.77, and mean particle size of 739.6 nm was obtained.

Comparative Example 1.4

[0163] The mixture of 188.14 g of Desmophen 1652, 198.6 g of PTHF 2000, 86.55 g of PTHF 1000 and 16.2 g of Polyether LB 25 was combined with 58.69 g of Desmodur I and 49.00 g of Desmodur H at 70° C., heated up to 120° C. and stirred at 120° C. until a constant NCO value of 3.43% by weight was achieved. The prepolymer was dissolved with 1324.41 g of acetone below 90° C. and stirred for 20 minutes. A mixture of 1.23 g of hydrazine Hydrate, 13.20 g of diaminosulfonate and 52.65 g of water was added at 40° C. within 5 minutes and stirred for 20 minutes. A mixture of 20.81 g of IPDA and 130.59 g of water was added at 40° C. within 8 minutes. 277.4 g of water was added at 40° C. within 15 minutes and mixed for 5 minutes before acetone was distilled. The final dispersion was filtered through 260 micron filter.

[0164] Dispersion with a solid content of 60.69% by weight, viscosity of 901.8 cps at 23° C., pH of 6.95, and mean particle size of 999.8 nm was obtained.

Comparative Example 1.5

[0165] The mixture of 248.8 g of Desmophen C 2613, 11.3 g of Polyether LB 25, 9.9 g of DMPA and 6.5 g of Neopentylglycol were combined with 14.3 g of Desmodur I and 85.4 g of Desmodur W at 75° C., heated up to 120° C. and stirred at 120° C. until a constant NCO value of 2.5% by weight was achieved. The prepolymer was dissolved with 609.1 g of acetone below 90° C. and stirred for 20 minutes. A mixture of 3.2 g of hydrazine Hydrate, 5.3 g of triethylamine, and 5.1 g of diethylenetriamine and 37.5 g of water was added at 40° C. within 5 minutes and stirred for 20 minutes before acetone was distilled. The final dispersion was filtered through 260 micron filter.

[0166] Dispersion with a solid content of 40.69%, viscosity of 223.8 cps at 23° C., pH of 7.46, and mean particle size of 63.5 nm was obtained.

TABLE-US-00001 TABLE 1 Results of testings Comp. Comp. Comp. Comp. Comp. Exp. Exp. Exp. Exp. Exp. Exp. Exp. Exp. 1.1 1.1 1.2 1.3 1.4 1.2 2.1 1.5 Thickness 0.2 ± 0.01 [mm] Tensile strength 27.97 16.01 10.02 10.1 5.63 23.73 13.05 crack [N/mm.sup.2] Elongation 1617.11 985.93 897.84 1128.84 911.83 1337.67 1724.00 crack [%] 100% Modulus 1.66 2.00 2.04 1.43 1.37 1.97 0.71 crack [N/mm.sup.2]

[0167] Comparative example 1.1 and comparative example 1.2 are using crystalized polycarbonates Desmophen C 2200 and Desmophen C 2613 respectively while example 1.1 is using amorphous polycarbonate Desmophen C 3200. By comparing with comparative example 1.1 and comparative example 1.2, example 1.1 has higher tensile strength and elongation but lower modulus.

[0168] Comparative example 1.3 and comparative example 1.4 are using amorphous polyesters PE 170 HN and Desmophen 1652 respectively. From the results, it can be found that their modulus decrease when amorphous polycarbonate is replaced by eq. mol of amorphous polyester while other compositions keep same, however, their tensile strength also reduces sharply, that is, their mechanical performance becomes worse compared with example 1.1.

[0169] Keep the same type of amorphous polycarbonate, we use short-chain or lower-molecular weight polycarbonate Desmophen C 3100 to replace Desmophen C 3200 and obtain example 1.2. Compared with that of comparative example 1.1 and comparative example 1.2 which contain crystal polycarbonate polyols, the modulus of example 1.2 reduces slightly and tensile strength enhances. Compared with higher-molecular amorphous polycarbonate polyol Desmophen C 3200, Desmophen C 3100 can't make the modulus lower efficiently. So it is better to use long-chain amorphous polycarbonate Desmophen C 3200 to efficiently achieve low modulus at the same time to have high tensile strength.

[0170] In addition to the above systems, we also can use Desmophen C 3200 to achieve low modulus and high tensile strength in other systems. Example 2.1 have a lower ratio of NCO to OH in prepolymer and lower modulus than that of example 1.1 and example 1.2. Example 2.1 contains Desmophen C 3200 and achieve lower modulus but higher tensile strength and elongation.

[0171] Therefore, no matter for high modulus system or for low modulus system, The amorphous polycarbonate polyols Desmophen C 3200 and Desmophen C 3100 make the PUDs to be the materials with low modulus but high tensile strength.