Polyurethane-Acrylate Water Repellant Fabric

Example 1

Investigation of Effects of Different Molar Ratios of Isocyanate Radical to Hydroxyl on Water Repellant:

A Polyurethane-acrylate water repellant was prepared according to the following steps and the fabric was finished:

Preparation of Polyurethane-Acrylate Water Repellant:

Preparation of Waterborne Polyurethane Self-Emulsion with Carbon-Carbon Double Bonds in Side Chain:

• • (1) Polytetrahydrofuran (Mn=850, accounting for 95% of the total mass of hydroxyl), 2,2-dimethylolbutanoic acid (accounting for 4% of the total mass of hydroxyl), and 1,5-hexadiene-3,4-diol (accounting for 1% of the total mass of hydroxyl) were dried in vacuum at a temperature of 70° C. to remove water for 3-4 h. Under the protection of nitrogen, in the presence of dibutyltin dilaurate as a catalyst (accounting for 0.08% of the total mass of the monomer participating in the reaction), isophorone diisocyanate was slowly added dropwise into the reaction system containing polytetrahydrofuran and 30% of 2,2-dimethylolbutanoic acid (the molar ratios of isocyanate radical to hydroxyl were 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, and 1.7, respectively), the reaction temperature was 80° C., and the next step was executed after the −NCO % content in the reaction system reached the theoretical value by using a di-n-butylamine method (the theoretical remaining amount of isocyanate radical≤32%);
  • (2) The temperature was reduced to 60° C., trimethylolpropane monoallyl ether (accounting for 1% of the total mass of hydroxyl) was slowly added dropwise, and after the —NCO % value was determined to reach the theoretical value (the theoretical remaining amount of isocyanate radical≤12-16%), 2,2-dimethylolbutanoic acid (accounting for 4% of the total mass of hydroxyl) was added to perform a thermal reaction until the —NCO content in the reaction system reached the theoretical value (the theoretical remaining amount of isocyanate radical≤8%);
  • (3) the temperature was reduced to 50° C., the polyurethane was blocked with butanone oxime (the molar ratio of the remaining isocyanate radical content in the reaction system to the hydroxyl of the added blocking agent is 1.5), NCO % was determined to be≤0.5% and then the next step was executed;
  • (4) the temperature was reduced to room temperature, triethylamine (neutralization degree: 80%) was added to adjust the reaction pH (pH=7.5±0.5), and deionized water was added according to the solid content of 20% and stirred at a high speed (r=1000 r/min) to be self-emulsified to obtain the waterborne polyurethane self-emulsion.

Preparation of Water Repellant by Reacting Acrylate with Waterborne Polyurethane Self-Emulsion with Carbon-Carbon Double Bonds in Side Chain:

The above waterborne polyurethane emulsion with carbon-carbon double bonds in the side chain was taken and the temperature was raised to 50° C., dodecyl acrylate, butyl acrylate and methyl methacrylate were added dropwise to the polyurethane emulsion according to the molar ratio of 1:1:1 (the mass ratio of the acrylate monomer to the solid content of the polyurethane self-emulsion with carbon-carbon double bonds in the side chain was 1:1), stirred for 15 min (r=4000 r/min) under a high-speed mixer, and then kept standing for 1 h, the temperature was raised to 75° C., a potassium persulfate initiator (accounting for 0.6% of the total mass of acrylate monomer) was slowly added dropwise within 3 hours, and the material was cooled and discharged after holding for 3 h to obtain the polyurethane-acrylate water repellant (WPUA).

Finishing of Fabric by Polyurethane-Acrylate Water Repellant:

By using a padding, drying and curing process, the fabric was emulsified by the water repellant at a padding residual ratio of 70% and a padding concentration of 180 g/L and then pre-dried at a temperature of 100° C. for 3 min and cured and dried at a temperature of 140° C. for 3 min. The relevant parameters of the finished fabric are shown in Table 1.

Hydrophobic effect of product: by comparing the polyurethane acrylate water repellant prepared according to different ratios, when the ratio was 1.1 or 1.7, the prepared polyurethane emulsion was unstable and could not effectively perform a free radical polymerization with acrylate monomers. When the ratio was 1.2-1.6, the water repellant was stable, and has better water repellant effects, and good pilling resistance.

Fastness to washing of product: after the fabric was finished with the water repellant emulsion prepared according to the ratio of 1.2-1.6, the static water contact angle (hydrophobicity) of the fabric after washing, equivalent to 25 times of washing with the domestic washing machine, was higher than 140°, and the hydrophobicity was higher, indicating that the fabric finished with the water repellant prepared by the disclosure has higher fastness to washing.

Hydrophobic effect repeatability of product: the fabric was finished when the molar ratio of isocyanate radical to hydroxyl was 1.2-1.6, after 10 batches of finishing, the static water contact angle of the fabric finished each time had a range error of ±1°, and it could be seen from the contact angle data that the hydrophobic effect repeatability of the fabric was good.

A block type waterborne polyurethane modified acrylate water repellant was prepared according to the following steps and the fabric was finished:

Preparation of Waterborne Polyurethane Self-Emulsion with Carbon-Carbon Double Bonds at the End:

• • (1) Polytetrahydrofuran (Mn=850, accounting for 95% of the total mass of hydroxyl), 2,2-dimethylolbutanoic acid (accounting for 4% of the total mass of hydroxyl), and hydroxyethyl acrylate (accounting for 1% of the total mass of hydroxyl) were dried in vacuum at a temperature of 70° C. to remove water for 2-3 h. Under the protection of nitrogen, in the presence of dibutyltin dilaurate as a catalyst (accounting for 0.08% of the total mass of the monomer participating in the reaction), isophorone diisocyanate was slowly added dropwise into the reaction system containing polytetrahydrofuran and 30% of 2,2-dimethylolbutanoic acid (the molar ratio of isocyanate radical to hydroxyl was 1.3), the reaction temperature was 80° C., and the next step was executed after the —NCO content in the reaction system reached the theoretical value by using a di-n-butylamine method (the theoretical remaining amount of isocyanate radical≤32%);
  • (2) the temperature was reduced to 60° C., 2,2-dimethylolbutanoic acid (accounting for 4% of the total mass of hydroxyl) was slowly added dropwise to perform a thermal reaction until the —NCO content in the reaction system reached the theoretical value (the theoretical remaining amount of isocyanate radical≤8%);
  • (3) the temperature was reduced to 50° C., the polyurethane was blocked with hydroxyethyl acrylate (the molar ratio of the remaining isocyanate radical content in the reaction system to the hydroxyl of the added blocking agent was 1.5), NCO % was determined to be ≤0.5% and then the next step was executed;
  • (4) the temperature was reduced to room temperature, triethylamine (neutralization degree: 80%) was added to adjust the reaction pH (pH=7.5±0.5), and deionized water was added according to the solid content of 20% and stirred at a high speed (r=1000 r/min) to be self-emulsified to obtain the waterborne polyurethane self-emulsion.

Preparation of Water Repellant by Reacting Acrylate with Waterborne Polyurethane Self-Emulsion with Carbon-Carbon Double Bonds in Side Chain:

The above waterborne polyurethane emulsion with carbon-carbon double bonds in the side chain was taken and the temperature was raised to 50° C., dodecyl acrylate, butyl acrylate and methyl methacrylate were added dropwise to the polyurethane emulsion according to 1:1:1 (the mass ratio of the acrylate monomer to the solid content of the polyurethane self-emulsion with carbon-carbon double bonds in the side chain was 1:1), stirred for 15 min (r=4000 r/min) under a high-speed mixer, and then kept standing for 1 h, the temperature was raised to 75° C., a potassium persulfate initiator (accounting for 0.6% of the total mass of acrylate monomer) was slowly added dropwise within 3 hours, and the material was cooled and discharged after holding for 3 h to obtain the polyurethane-acrylate water repellant (WPUA).

Finishing of Fabric by Polyurethane-Acrylate Water Repellant:

By using a padding, drying and curing process, the fabric was emulsified by the water repellant at a padding residual ratio of 70% and a padding concentration of 180 g/L and then pre-dried at a temperature of 100° C. for 3 min and cured and dried at a temperature of 140° C. for 3 min. The relevant parameters of the finished fabric are shown in Table 3.

Example 2

Investigation of Effects of Reaction Conditions of Acrylate and Waterborne Polyurethane Self-Emulsion on Water Repellant:

Preparation of Polyurethane Self-Emulsion:

the molar ratio of isocyanate radical to hydroxyl of 1.3 was selected, and other conditions referred to Embodiment 1 to prepare a polyurethane self-emulsion.

Preparation of Water Repellant by Reacting Acrylate with Waterborne Polyurethane Self-Emulsion with Carbon-Carbon Double Bonds in Side Chain:

The above waterborne polyurethane emulsion with carbon-carbon double bonds in the side chain was taken and the temperature was raised to 50° C., the molar ratio of dodecyl acrylate to butyl acrylate to methyl methacrylate was respectively replaced to 2:1:0, 1:2:0, 0:2:1, and 0:1:2 (the mass ratio of the acrylate monomer to the solid content of the polyurethane self-emulsion with carbon-carbon double bonds in the side chain was 1:1), they were added dropwise to the polyurethane emulsion, stirred for 15 min (r=4000 r/min) under a high-speed mixer, and then kept standing for 1 h, the temperature was raised to 75° C., a potassium persulfate initiator (accounting for 0.6% of the total mass of acrylate monomer) was slowly added dropwise within 3 hours, and the material was cooled and discharged after holding for 3 h to obtain the polyurethane-acrylate water repellant (WPUA).

Finishing of Fabric by Polyurethane-Acrylate Water Repellant:

By using a padding, drying and curing process, the fabric was emulsified by the water repellant at a padding residual ratio of 70% and a padding concentration of 180 g/L and then pre-dried at a temperature of 100° C. for 3 min and cured and dried at a temperature of 140° C. for 3 min. The relevant parameters of the finished fabric are shown in Table 2.

Hydrophobic effect of product: by comparing the polyurethane acrylate water repellant prepared according to different acrylate monomer ratios, the water repellant was stable, and the finished fabric has better water repellant effects, and good pilling resistance.

Fastness to washing of product: by comparing the polyurethane acrylate water repellant prepared according to different acrylate monomer ratios, the static water contact angle (hydrophobicity) of the fabric after washing, equivalent to 25 times of washing with the domestic washing machine, was higher than 142°, and the hydrophobicity was higher, indicating that the fabric finished with the water repellant prepared by the disclosure has higher fastness to washing.

Hydrophobic effect repeatability of product: by comparing the polyurethane acrylate water repellant prepared according to different acrylate monomer ratios, after 10 batches of finishing, the static water contact angle of the fabric finished each time had a range error of ±1°, and it could be seen from the contact angle data that the hydrophobic effect repeatability of the fabric was good.

A grafted waterborne polyurethane modified acrylate water repellant was prepared according to the following steps and the fabric was finished:

Preparation of Waterborne Polyurethane Self-Emulsion with Carbon-Carbon Double Bonds in Main Chain:

• • (1) Polytetrahydrofuran (Mn=850, accounting for 95% of the total mass of hydroxyl), 2,2-dimethylolbutanoic acid (accounting for 4% of the total mass of hydroxyl), and butenediol (accounting for 1% of the total mass of hydroxyl) were dried in vacuum at a temperature of 70° C. to remove water for 2-3 h. Under the protection of nitrogen, in the presence of dibutyltin dilaurate as a catalyst (accounting for 0.08% of the total mass of the monomer participating in the reaction), isophorone diisocyanate was slowly added dropwise to polytetrahydrofuran and 30% of 2,2-dimethylolbutanoic acid (the molar ratio of isocyanate radical to hydroxyl was 1.3), the reaction temperature was 80° C., and the next step was executed after the —NCO content in the reaction system reached the theoretical value by using a di-n-butylamine method (the theoretical remaining amount of isocyanate radical≤32%);
  • (2) The temperature was reduced to 60° C., butenediol (accounting for 1% of the total mass of hydroxyl) was slowly added dropwise, and after the —NCO % value was determined to reach the theoretical value (the theoretical remaining amount of isocyanate radical≤14%), 2,2-dimethylolbutanoic acid (accounting for 4% of the total mass of hydroxyl) was added to perform a thermal reaction until the —NCO content in the reaction system reached the theoretical value (the theoretical remaining amount of isocyanate radical≤8%);
  • (3) the temperature was reduced to 50° C., the polyurethane was blocked with butanone oxime (the molar ratio of the remaining isocyanate radical content in the reaction system to the hydroxyl of the added blocking agent is 1.5), the NCO % was determined to be ≤0.5% and then the next step was executed;
  • (4) the temperature was reduced to room temperature, triethylamine (neutralization degree: 80%) was added to adjust the reaction pH (pH=7.5±0.5), and deionized water was added according to the solid content of 20% and stirred at a high speed (r=1000 r/min) to be self-emulsified to obtain the waterborne polyurethane self-emulsion.

Preparation of Water Repellant by Reacting Acrylate with Waterborne Polyurethane Self-Emulsion with Carbon-Carbon Double Bonds in Main Chain:

The above waterborne polyurethane emulsion with carbon-carbon double bonds in the main chain was taken and the temperature was raised to 50° C., dodecyl acrylate, butyl acrylate and methyl methacrylate were added dropwise to the polyurethane emulsion according to 1:1:1 (the mass ratio of the acrylate monomer to the solid content of the polyurethane self-emulsion with carbon-carbon double bonds in the side chain was 1:1), stirred for 15 min (r=4000 r/min) under a high-speed mixer, and then kept standing for 1 h, the temperature was raised to 75° C., a potassium persulfate initiator (accounting for 0.6% of the total mass of acrylate monomer) was slowly added dropwise within 3 hours, and the material was cooled and discharged after holding for 3 h to obtain the polyurethane-acrylate water repellant (WPUA).

Finishing of Fabric by Polyurethane-Acrylate Water Repellant:

By using a padding, drying and curing process, the fabric was emulsified by the water repellant at a padding residual ratio of 70% and a padding concentration of 180 g/L and then pre-dried at a temperature of 100° C. for 3 min and cured and dried at a temperature of 140° C. for 3 min. The relevant parameters of the finished fabric are shown in Table 3.

Example 3

A polyurethane-acrylate water repellant was prepared according to the following steps and the fabric was finished:

Preparation of Polyurethane-Acrylate Water Repellant:

Preparation of Waterborne Polyurethane Self-Emulsion with Carbon-Carbon Double Bonds in Side Chain:

• • (1) Polypropylene glycol (Mn=2000, accounting for 79% of the total mass of hydroxyl), 2,2-dimethylolpropionic acid (accounting for 11% of the total mass of hydroxyl), and 7-octene-1,2-diol (accounting for 10% of the total mass of hydroxyl) were dried in vacuum at a temperature of 70° C. to remove water for 3-4 hours. Under the protection of nitrogen, in the presence of dibutyltin dilaurate as a catalyst (accounting for 0.08% of the total mass of the monomer participating in the reaction), p-phenylene diisocyanate was slowly added dropwise into the reaction system containing polypropylene glycol and 30% of 2,2-dimethylolpropionic acid (the molar ratio of isocyanate radical to hydroxyl was 1.3), the reaction temperature was 80° C., and the next step was executed after the —NCO % content in the reaction system reached the theoretical value by using a di-n-butylamine method (the theoretical remaining amount of isocyanate radical≤32%);
  • (2) the temperature was reduced to 65° C., 7-octene-1,2-diol (accounting for 10% of the total mass of hydroxyl) was slowly added dropwise, and after the —NCO % value was determined to reach the theoretical value (the theoretical remaining amount of isocyanate radical≤12%), 2,2-dimethylolpropionic acid (accounting for 11% of the total mass of hydroxyl) was added to perform a thermal reaction until the —NCO content in the reaction system reached the theoretical value (the theoretical remaining amount of isocyanate radica≤8%);
  • (3) the temperature was reduced to 60° C., the polyurethane was blocked with n-heptaldehyde oxime (the molar ratio of the remaining isocyanate radical content in the reaction system to the hydroxyl of the added blocking agent was 2), NCO % was determined to be≤0.5% and then the next step was executed;
  • (4) the temperature was reduced to room temperature, triethylamine (neutralization degree: 100%) was added to adjust the reaction pH (pH=7.5±0.5), and deionized water was added according to the solid content of 40% and stirred at a high speed (r=1600 r/min) to be self-emulsified to obtain the waterborne polyurethane self-emulsion.

Preparation of Water Repellant by Reacting Acrylate with Waterborne Polyurethane Self-Emulsion with Carbon-Carbon Double Bonds in Side Chain:

The above waterborne polyurethane emulsion with carbon-carbon double bonds in the side chain was taken and the temperature was raised to 40° C., octadecyl acrylate, tetradecyl acrylate and methyl methacrylate were added dropwise to the polyurethane emulsion according to 2:1:0 (the mass ratio of the acrylate monomer to the solid content of the polyurethane self-emulsion with carbon-carbon double bonds in the side chain was 4:1), stirred for 20 min (r=5000 r/min) under a high-speed mixer, and then kept standing for 1.5 h, the temperature was raised to 80° C., a potassium persulfate initiator (accounting for 0.8% of the total mass of acrylate monomer) was slowly added dropwise within 4 hours, and the material was cooled and discharged after holding for 2 h to obtain the polyurethane-acrylate water repellant (WPUA).

Finishing of Fabric by Polyurethane-Acrylate Water Repellant:

By using a padding, drying and curing process, the fabric was emulsified by the water repellant at a padding residual ratio of 150% and a padding concentration of 20 g/L and then pre-dried at a temperature of 60° C. for 5 min and cured and dried at a temperature of 160° C. for 1 min. The relevant parameters of the finished fabric are shown in Table 3.

Referring to Embodiment 6, other conditions remained unchanged, and the dihydroxy-containing double bond monomer was replaced with 1,5-hexadiene-3,4-diol to prepare a hydrophobic fabric. Relevant test results are shown in Table 3.

Hydrophobic effect of product: the disclosure introduced carbon-carbon double bonds in the polyurethane side chain by using the double carbon-carbon double bond-containing dihydroxy micromolecular chain extender (Embodiments 1-6), and compared with the introduction of carbon-carbon double bonds at the polyurethane end (Comparative Example 1) and the introduction of carbon-carbon double bonds inside the polyurethane main chain (Comparative Example 2 and Comparative Example 3), the water repellant prepared according to the steps of Embodiments 1-6 was more stable, and the finished fabric had better water repellant effects, and good pilling resistance.

Fastness to washing of product: by comparing the polyurethane acrylate water repellant prepared according to different acrylate monomer ratios in Embodiments 1-6, the static water contact angle (hydrophobicity) of the fabric after washing, equivalent to 25 times of washing with domestic washing machines, was higher than 142°, and the hydrophobicity was higher, indicating that the fabric finished with the water repellant prepared by the disclosure has higher fastness to washing.

Hydrophobic effect repeatability of product: by comparing the polyurethane acrylate water repellant prepared according to different acrylate monomer ratios Embodiments 1-6, after 10 batches of finishing, the static water contact angle of the fabric finished each time had a range error of ±1°, and it could be seen from the contact angle data that the hydrophobic effect repeatability of the fabric was good.

Only preferred implementations of the disclosure are described above. It should be noted that for those of ordinary skill in the art, several improvements and modifications can be made without departing from the principles of the disclosure. These improvements and modifications should also be regarded as the protection scope of the disclosure.

Example 4

A polyurethane-acrylate water repellant was prepared according to the following steps and the fabric was finished:

Preparation of Polyurethane-Acrylate Water Repellant:

Preparation of Waterborne Polyurethane Self-Emulsion with Carbon-Carbon Double Bonds in Side Chain:

• • (1) Poly-ε-caprolactone glycol (Mn=300, accounting for 80% of the total mass of hydroxyl), 2,2-dimethylolbutanoic acid (accounting for 10% of the total mass of hydroxyl), and 6-heptene-2,4-diol (accounting for 10% of the total mass of hydroxyl) were dried in vacuum at a temperature of 70° C. to remove water for 3-4 h. Under the protection of nitrogen, in the presence of dibutyltin dilaurate as a catalyst (accounting for 0.08% of the total mass of the monomer participating in the reaction), diphenylmethane diisocyanate was slowly added dropwise into the reaction system containing poly-ε-caprolactone glycol and 30% of hydroxymethylpropionic acid (the molar ratio of isocyanate radical to hydroxyl was 1.3), the reaction temperature was 75° C., and the next step was executed when the —NCO % content in the reaction system reached the theoretical value by using a di-n-butylamine method (the theoretical remaining amount of isocyanate radical≤32%);
  • (2) The temperature was reduced to 60° C., 6-heptene-2,4-diol (accounting for 10% of the total mass of hydroxyl) was slowly added dropwise, and after the —NCO % value was determined to reach the theoretical value (the theoretical remaining amount of isocyanate radical≤14%), 2,2-dimethylolbutanoic acid (accounting for 10% of the total mass of hydroxyl) was added to perform a thermal reaction until the —NCO content in the reaction system reached the theoretical value (the theoretical remaining amount of isocyanate radical≤8%);
  • (3) the temperature was reduced to 50° C., the polyurethane was blocked with cyclohexanone oxime (the molar ratio of the remaining isocyanate radical content in the reaction system to the hydroxyl of the added blocking agent was 1.8), NCO % was determined to be ≤0.5% and then the next step was executed;
  • (4) the temperature was reduced to room temperature, triethylamine (neutralization degree: 90%) was added to adjust the reaction pH (pH=7.5±0.5), and deionized water was added according to the solid content of 30% and stirred at a high speed (r=1600 r/min) to be self-emulsified to obtain the waterborne polyurethane self-emulsion.

Preparation of Water Repellant by Reacting Acrylate with Waterborne Polyurethane Self-Emulsion with Carbon-Carbon Double Bonds in Side Chain:

The above waterborne polyurethane emulsion with carbon-carbon double bonds in the side chain was taken and the temperature was raised to 50° C., dodecyl methacrylate and butyl acrylate were added dropwise to the polyurethane emulsion according to 1:2 (the mass ratio of the acrylate monomer to the solid content of the polyurethane self-emulsion with carbon-carbon double bonds in the side chains was 3:1), stirred for 15 min (r=4500 r/min) under a high-speed mixer, and then kept standing for 1 h, the temperature was raised to 75° C., an azobisisobutyronitrile initiator (accounting for 0.7% of the total mass of acrylate monomer) was slowly added dropwise within 3.5 hours, and the material was cooled and discharged after holding for 3 h to obtain the polyurethane-acrylate water repellant (WPUA).

Finishing of Fabric by Polyurethane-Acrylate Water Repellant:

By using a padding, drying and curing process, the fabric was emulsified by the water repellant at a padding residual ratio of 100% and a padding concentration of 120 g/L, and then pre-dried at a temperature of 90° C. for 3 min and cured and dried at a temperature of 140° C. for 2 min. The relevant parameters of the finished fabric are shown in Table 3.

Example 5

A polyurethane-acrylate water repellant was prepared according to the following steps and the fabric was finished:

Preparation of Polyurethane-Acrylate Water Repellant:

Preparation of Waterborne Polyurethane Self-Emulsion with Carbon-Carbon Double Bonds in Side Chain:

• • (1) polyethyleneglycol adipate glycol (Mn=1500, accounting for 85% of the total mass of hydroxyl), N-methyldiethanolamine (accounting for 10% of the total mass of hydroxyl), and pentaerythritol diacrylate (accounting for 5% of the total mass of hydroxyl) were dried in vacuum at a temperature of 70° C. to remove water for 3-4 h. Under the protection of nitrogen, in the presence of dibutyltin dilaurate as a catalyst (accounting for 0.08% of the total mass of the monomer participating in the reaction), 4,4-diphenylmethane diisocyanate was slowly added dropwise into the reaction system containing polyethyleneglycol adipate glycol and 30% of N-methyldiethanolamine (the molar ratio of isocyanate radical to hydroxyl was 1.3), the reaction temperature was 80° C., and the next step was executed after the —NCO % content in the reaction system reached the theoretical value by using a di-n-butylamine method (the theoretical remaining amount of isocyanate radical≤32%);
  • (2) the temperature was reduced to 50° C., pentaerythritol diacrylate (accounting for 5% of the total mass of hydroxyl) was slowly added dropwise, and after the —NCO % value was determined to reach the theoretical value (the theoretical remaining amount of isocyanate radical≤14%), N-methyldiethanolamine (accounting for 10% of the total mass of hydroxyl) was added to perform a thermal reaction until the —NCO content in the reaction system reached the theoretical value (the theoretical remaining amount of isocyanate radical≤8%);
  • (3) the temperature was reduced to 60° C., the polyurethane was blocked with butanone oxime (the molar ratio of the remaining isocyanate radical content in the reaction system to the hydroxyl of the added blocking agent was 1.6), NCO % was determined to be ≤0.5% and then the next step was executed;
  • (4) the temperature was reduced to room temperature, hydrochloric acid (neutralization degree: 85%) was added to adjust the reaction pH (pH=7.5±0.5), and deionized water was added according to the solid content of 35% and stirred at a high speed (r=1600 r/min) to be self-emulsified to obtain the waterborne polyurethane self-emulsion.

Preparation of Water Repellant by Reacting Acrylate with Waterborne Polyurethane Self-Emulsion with Carbon-Carbon Double Bonds in Side Chain:

The above waterborne polyurethane emulsion with carbon-carbon double bonds in the side chain was taken and the temperature was raised to 45° C., octadecyl acrylate and butyl acrylate were added dropwise to the polyurethane emulsion according to 2:1 (the mass ratio of the acrylate monomer to the solid content of the polyurethane self-emulsion with carbon-carbon double bonds in the side chain was 2:1), stirred for 20 min (r=5000 r/min) under a high-speed mixer, and then kept standing for 1.5 h, the temperature was raised to 80° C., an azobisisobutyronitrile initiator (accounting for 0.6% of the total mass of acrylate monomer) was slowly added dropwise within 4 hours, and the material was cooled and discharged after holding for 2 h to obtain the polyurethane-acrylate water repellant (WPUA).

Finishing of Fabric by Polyurethane-Acrylate Water Repellant:

By using a padding, drying and curing process, the fabric was emulsified by the water repellant at a padding residual ratio of 80% and a padding concentration of 160 g/L and then pre-dried at a temperature of 70° C. for 5 min and cured and dried at a temperature of 150° C. for 4 min. The relevant parameters of the finished fabric are shown in Table 3.

Example 6

A polyurethane-acrylate water repellant was prepared according to the following steps and the fabric was finished:

Preparation of Polyurethane-Acrylate Water Repellant:

Preparation of Waterborne Polyurethane Self-Emulsion with Carbon-Carbon Double Bonds in Side Chain:

• • Polyethylene glycol (Mn=600, accounting for 90% of the total mass of hydroxyl), diethylenetriamine (accounting for 4% of the total mass of hydroxyl), and glycerol methacrylate (accounting for 6% of the total mass of hydroxyl) were dried in vacuum at a temperature of 70° C. to remove water for 3-4 h. Under the protection of nitrogen, in the presence of dibutyltin dilaurate as a catalyst (accounting for 0.08% of the total mass of the monomer participating in the reaction), m-phenylene diisocyanate was slowly added dropwise into the reaction system containing polyethylene glycol and 30% of diethylenetriamine (the molar ratio of isocyanate radical to hydroxyl was 1.3), the reaction temperature was 70° C., and the next step was executed after the —NCO content in the reaction system reached the theoretical value by using a di-n-butylamine method (the theoretical remaining amount of isocyanate radical≤32%);
  • (2) The temperature was reduced to 60° C., glycerol methacrylate (accounting for 6% of the total mass of hydroxyl) was slowly added dropwise, and after the —NCO % value was determined to reach the theoretical value (the theoretical remaining amount of isocyanate radical≤14%), diethylenetriamine (accounting for 4% of the total mass of hydroxyl) was added to perform a thermal reaction until the —NCO content in the reaction system reached the theoretical value (the theoretical remaining amount of isocyanate radical≤8%);
  • (3) the temperature was reduced to 50° C., the polyurethane was blocked with dimethyl glyoxime (the molar ratio of the remaining isocyanate radical content in the reaction system to the hydroxyl of the added blocking agent was 1.5), NCO % was determined to be ≤0.5% and then the next step was executed;
  • (4) the temperature was reduced to room temperature, hydrochloric acid (neutralization degree: 95%) was added to adjust the reaction pH (pH=7.5±0.5), and deionized water was added according to the solid content of 25% and stirred at a high speed (r=1600 r/min) to be self-emulsified to obtain the waterborne polyurethane self-emulsion.

Preparation of Water Repellant by Reacting Acrylate with Waterborne Polyurethane Self-Emulsion with Carbon-Carbon Double Bonds in Side Chain:

The above waterborne polyurethane emulsion with carbon-carbon double bonds in the side chain was taken and the temperature was raised to 40° C., hexyl acrylate, hexyl methacrylate and octyl methacrylate were added dropwise to the polyurethane emulsion according to 1:1:1 (the mass ratio of the acrylate monomer to the solid content of the polyurethane self-emulsion with carbon-carbon double bonds in the side chain was 3:1), stirred for 15 min (r=5000 r/min) under a high-speed mixer, and then kept standing for 1 h, the temperature was raised to 75° C., a potassium persulfate initiator (accounting for 0.7% of the total mass of acrylate monomer) was slowly added dropwise within 4 hours, and the material was cooled and discharged after holding for 3 h to obtain the polyurethane-acrylate water repellant (WPUA).

Finishing of Fabric by Polyurethane-Acrylate Water Repellant:

By using a padding, drying and curing process, the fabric was emulsified by the water repellant at a padding residual ratio of 70% and a padding concentration of 180 g/L and then pre-dried at a temperature of 60° C. for 5 min and cured and dried at a temperature of 150° C. for 2 min. The relevant parameters of the finished fabric are shown in Table 3.