Waterborne polyurethane with long-acting antifouling property as well as preparation method and application of waterborne polyurethane

Abstract

The invention belongs to the technical field of leather finishing agents, and discloses waterborne polyurethane with long-acting antifouling performance and a preparation method and application thereof. The invention relates to waterborne polyurethane with long-acting antifouling property. The waterborne polyurethane is prepared from the following raw materials in parts by weight: 40 to 72 parts of hydrophobic solvent, 4 to 10 parts of cross-linking agent, 100 to 180 parts of polypropylene carbonate polyol, 100 to 324 parts of diisocyanate, 8 to 14 parts of tertiary amine compound and 200 to 600 parts of deionized water. Wherein the hydrophobic solvent is obtained by mixing and reacting quaternary ammonium salt and fatty acid according to the mass ratio of 1: (1-2). The waterborne polyurethane provided by the invention is stable in performance and relatively good in film-forming ability, due to the use of the component hydrophobic solvent, the reaction efficiency and the purity of a product can be improved, a certain antibacterial property is provided for the waterborne polyurethane, an adhesive film formed by the waterborne polyurethane has long-acting antifouling performance, and the flexibility and glossiness are improved. The waterborne polyurethane disclosed by the invention is used for leather finishing, and the finished leather still has better physical properties after being stored for 6 months.

Description

Technical Field

[0001] The invention relates to the technical field of leather finishing, and in particular to a waterborne polyurethane with long-lasting antifouling performance and a preparation method and application thereof. Background Art

[0002] Finishing is an important process in the leather production process, which affects the appearance, texture, waterproofness, durability and other properties of leather products. As an environmentally friendly material, waterborne polyurethane is gradually replacing solvent-based polyurethane due to its low volatile organic compound (VOCs) emissions, green and safe characteristics, and is widely used in leather finishing. However, due to the presence of a large number of hydrophilic groups in the molecular chain, traditional waterborne polyurethane has a high surface energy and poor hydrophobic properties. It is difficult to meet the antifouling requirements of leather when used in leather preparation, and it is easily contaminated by microorganisms. It also has deficiencies in antibacterial properties, which affects the service life and safety of leather. Therefore, research and development of waterborne polyurethane with excellent antifouling and antibacterial properties has important theoretical significance and practical value. Summary of the invention

[0003] The purpose of the present invention is to provide a waterborne polyurethane with long-lasting antifouling performance and a preparation method and application thereof, so as to improve the antifouling and antibacterial properties of the waterborne polyurethane after film formation, so that the waterborne polyurethane can be applied to leather finishing to give the leather better physical properties.

[0004] To achieve the above object, in a first aspect, the present invention provides an aqueous polyurethane with long-lasting antifouling performance, which is composed of the following raw materials in parts by weight: 40-72 parts of a hydrophobic solvent, 4-10 parts of a cross-linking agent, 100-180 parts of polypropylene carbonate polyol, 100-324 parts of a diisocyanate, 8-14 parts of a tertiary amine compound, and 200-600 parts of deionized water; The hydrophobic solvent is obtained by mixing a quaternary ammonium salt and a fatty acid in a mass ratio of 1:1-2.

[0005] The hydrophobic solvent is a transparent liquid and can only be obtained when the mass ratio of the quaternary ammonium salt to the fatty acid is 1:1-2. If the mass ratio of the quaternary ammonium salt to the fatty acid is changed, a solid-liquid mixture is obtained instead of a solvent, which is not suitable as a raw material for preparing the waterborne polyurethane of the present invention.

[0006] Preferably, the temperature of the mixed reaction is 50-80°C, the rotation speed is 100-250 r / min, and the time is 0.5-1.5h.

[0007] Preferably, the quaternary ammonium salt is any one of hexadecyldimethylammonium chloride, methylbenzenedimethylammonium chloride, and trimethylammonium bromide.

[0008] Preferably, the fatty acid is any one of n-octanoic acid, n-nonanoic acid, n-decanoic acid and lauric acid.

[0009] Preferably, the cross-linking agent is any one of KU-550, A-1100, Z-6011, KBE-903, and GF93.

[0010] Preferably, the polypropylene carbonate polyol is any one of polycarbonate diol and polycarbonate 1,6-hexanediol.

[0011] Preferably, the diisocyanate is any one of isophorone diisocyanate and hexamethylene diisocyanate.

[0012] Preferably, the tertiary amine compound is any one of triethylamine, dimethylethylamine, methyldiethanolamine and methyldiethylamine.

[0013] In a second aspect, the present invention provides a method for preparing an aqueous polyurethane having a long-lasting antifouling property, wherein a hydrophobic solvent is gradually polymerized with polypropylene carbonate polyol, diisocyanate, a crosslinking agent, and a tertiary amine compound, and then dispersed in deionized water. The specific preparation method is as follows: Adding polypropylene carbonate polyol and diisocyanate into a hydrophobic solvent to carry out a first reaction to obtain a first mixture; adding a cross-linking agent to the first mixture to carry out a second reaction to obtain a second mixture; adding a tertiary amine compound to the second mixture to carry out a third reaction to obtain a third mixture; Deionized water is added to the third mixture to carry out a fourth reaction to obtain a waterborne polyurethane having a long-lasting antifouling property.

[0014] Preferably, the temperature of the first reaction is 80-100°C, the rotation speed is 100-250 r / min, and the time is 1-3 h.

[0015] Preferably, the temperature of the second reaction is 80-100°C, the rotation speed is 100-250 r / min, and the time is 1-3 h.

[0016] Preferably, the temperature of the third reaction is 30-50°C, the rotation speed is 100-250 r / min, and the time is 0.5-1.5h.

[0017] Preferably, the temperature of the fourth reaction is 20-30°C, the rotation speed is 3000-5000 r / min, and the time is 0.1-0.5 h.

[0018] In a third aspect, the present invention provides the use of waterborne polyurethane with long-lasting antifouling performance in leather finishing.

[0019] The leather can be common leather products, such as sofa cushion leather and car cushion leather.

[0020] Compared with the prior art, the present invention has the following beneficial effects: In the waterborne polyurethane provided by the present invention, the hydrophobic solvent as a component can not only be used as a catalyst to improve the reaction efficiency and the purity of the product, but the quaternary ammonium salt in the hydrophobic solvent can also undergo a quaternization reaction with a tertiary amine compound to provide the waterborne polyurethane with certain antibacterial properties, and the fatty acid can also undergo an esterification reaction with polypropylene carbonate polyol, so that the film formed by the waterborne polyurethane has a long-term antifouling property, and the flexibility and glossiness are improved. In addition, the hydrophobic solvent can further adjust the physical and chemical properties of the waterborne polyurethane, such as viscosity, surface tension, density, etc., so that it can adapt to different application requirements.

[0021] The waterborne polyurethane provided by the present invention has stable performance, good film-forming ability, good fluidity, and is easy to use. Its preparation process is simple, and the processing conditions are mild. The green catalyst hydrophobic solvent used can be used as a solvent, a reactant, and a film-forming agent in the future without the need for separate separation and purification, which is in line with the concept of green environmental protection.

[0022] The waterborne polyurethane provided by the present invention is used in leather finishing, and the finished leather has good performance in terms of light fastness, color fastness to friction, water stain fastness, gloss, flexibility, oil stain resistance and antibacterial property, especially in terms of oil stain resistance. After storage for 6 months, the oil stain resistance remains unchanged, and the leather has long-lasting antifouling performance. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Example 1 Take 2 g of hexadecyldimethylammonium chloride and 2 g of n-octanoic acid, add them into a four-necked flask equipped with a high-speed shear stirrer and a reflux condenser, heat to 50 °C and react at 100 r / min for 0.5 h to obtain a transparent hydrophobic solvent, then heat to 80 °C, add 10 g of polycarbonate diol and 10 g of isophorone diisocyanate, react at 100 r / min for 1 h, then add 0.4 g of KU-550, continue to react at this temperature for 1 h, then cool to 30 °C, add 0.8 g of triethylamine and react for 0.5 h, then cool to 20 °C, add 20 g of deionized water, shear emulsify and disperse at 3000 r / min for 10 min to obtain waterborne polyurethane.

[0025] The waterborne polyurethane is in the form of an emulsion, milky white, and has no precipitation after centrifugation at 3000 r / min for 15 min. It can be stably stored for more than 6 months. The film formed is light yellow and transparent, relatively soft, non-sticky, and has a water absorption rate of 5.2%.

[0026] Example 2 Take 2 g of trimethylammonium bromide and 3 g of n-octanoic acid, add them into a four-necked flask equipped with a high-speed shear stirrer and a reflux condenser, heat to 80 °C and react at 250 r / min for 1.5 h to obtain a transparent hydrophobic solvent, then heat to 100 °C, add 18 g of polycarbonate 1,6-hexanediol and 32.4 g of hexamethylene diisocyanate, react for 3 h, add 1 g of A-1100, continue to react at this temperature for 3 h, then cool to 50 °C, add 1.4 g of dimethylethylamine and react for 1.5 h, cool to 30 °C, add 60 g of deionized water, shear emulsify and disperse at 5000 r / min for 30 min to obtain waterborne polyurethane.

[0027] The waterborne polyurethane is in the form of an emulsion, milky white, and has no precipitation after centrifugation at 3000 r / min for 15 min. It can be stably stored for more than 6 months. The film formed is light yellow and transparent, relatively soft, non-sticky, and has a water absorption rate of 5.0%.

[0028] Example 3 Take 2 g of methylbenzenedimethylammonium chloride and 4 g of n-decanoic acid, add them into a four-necked flask equipped with a high-speed shear stirrer and a reflux condenser, heat to 70 °C and react at 200 r / min for 1 h to obtain a transparent hydrophobic solvent, then heat to 90 °C, add 11 g of polycarbonate diol and 21.2 g of isophorone diisocyanate, react for 2 h, add 0.7 g of Z-6011, continue to react at this temperature for 2 h, then cool to 40 °C, add 1 g of methyldiethanolamine and react for 1 h, cool to 25 °C, add 40 g of deionized water, shear emulsify and disperse at 4000 r / min for 20 min to obtain waterborne polyurethane.

[0029] The waterborne polyurethane is in the form of an emulsion, milky white, and has no precipitation after centrifugation at 3000 r / min for 15 min. It can be stably stored for more than 6 months. The film formed is light yellow and transparent, relatively soft, non-sticky, and has a water absorption rate of 4.8%.

[0030] Comparative Example The difference from Example 1 is that the hydrophobic solvent is replaced by dibutyltin dilaurate, a common catalyst for preparing waterborne polyurethane. The specific preparation method is: Take 4 g of dibutyltin dilaurate, add it into a four-necked flask equipped with a high-speed shear stirrer and a reflux condenser, heat it to 80 °C, add 10 g of polycarbonate diol and 10 g of isophorone diisocyanate, react at 100 r / min for 1 h, then add 0.4 g of KU-550, continue to react at this temperature for 1 h, then cool to 30 °C, add 0.8 g of triethylamine and react for 0.5 h, then cool to 20 °C, add 20 g of deionized water, shear emulsify and disperse at 3000 r / min for 10 min to obtain waterborne polyurethane.

[0031] The waterborne polyurethane is in the form of an emulsion, milky white, and has no precipitation after centrifugation at 3000 r / min for 15 min. It can be stably stored for more than 6 months. The film formed is light yellow and transparent, relatively soft, non-sticky, and has a water absorption rate of 25%.

[0032] In the above embodiments and comparative examples, the water absorption rate of the film is determined as follows: Cut the film sample into small pieces of 2 cm × 2 cm or 3 cm × 3 cm, dry them at room temperature to constant weight to ensure the accuracy of the initial mass of the sample, weigh the mass of the sample at this time, and record it as the dry mass m0; Soak the dried sample in deionized water at room temperature for 24 hours. After soaking, quickly absorb the moisture on the surface of the sample with filter paper, weigh the mass of the sample, record it as the mass after soaking m1, and calculate the water absorption rate of the sample according to the following formula: .

[0033] Application test The waterborne polyurethanes of Examples 1-3 and the comparative example were used as leather finishing agents, and cowhide full-grain sofa leather (area 10 cm×10 cm) was finished according to the finishing process described in Table 1: Table 1 Coating process of cowhide full-grain sofa leather .

[0034] The performance of the cowhide full-grain sofa leather after the above-mentioned finishing treatment was measured by the following method: Color fastness to light: refer to ISO 105-B02:2014 Textiles - Tests for color fastness - Part B02: Color fastness to artificial light: Xenon arc lamp test; Color fastness to rubbing: refer to ISO 11640:2018 Leather color fastness test reciprocating rubbing color fastness; Color fastness to water stains: refer to ISO 11642:2012 Leather color fastness test for color fastness to washing; Adhesion strength: Refer to ISO 11644:2022 leather paint adhesion test; Bending resistance (flexibility): refer to ISO 5402-1:2022 Determination of flexural resistance of leather Part 1: Flexometer method; Tear strength: refer to ISO 3377-1:2011 Physical and mechanical tests on leather - Determination of tear force - Part 1: Single-sided tear; Yellowing resistance: After irradiation with 300 W solar light for 12 hours, determine the degree of discoloration of the sample; Glossiness: Invite professional technicians to visually judge the glossiness of leather under natural light; Antibacterial properties: measured using the oscillation method; Synthetic oil stain resistance: GB / T 41424.1-2022 Determination of stain resistance of leather Part 1: Tumbling method.

[0035] The above performance test results are shown in Table 2.

[0036] Table 2 Performance test results of cowhide full-grain sofa leather .

[0037] It can be seen from the performance test results in Table 2 that the indicators of the cowhide full-grain sofa leather coated with the water-based polyurethane of Example 1, Example 2 and Example 3 are better than those of the finished leather coated with the water-based polyurethane of the comparative example, especially the three indicators of synthetic oil stain resistance, glossiness and antibacterial property, which are significantly better than the sofa leather coated with the water-based polyurethane of the comparative example. The synthetic oil stain resistance of the sofa leather coated with the water-based polyurethane of the embodiment remains unchanged after being stored for six months, and it has long-lasting anti-fouling performance.

[0038] Finally, it should be noted that: Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A waterborne polyurethane with long-lasting antifouling performance, characterized in that: The invention is composed of the following raw materials in parts by weight: 40-72 parts of a hydrophobic solvent, 4-10 parts of a cross-linking agent, 100-180 parts of polypropylene carbonate polyol, 100-324 parts of a diisocyanate, 8-14 parts of a tertiary amine compound, and 200-600 parts of deionized water; The hydrophobic solvent is obtained by mixing a quaternary ammonium salt and a fatty acid in a mass ratio of 1:1-2.

2. The aqueous polyurethane with long-lasting antifouling performance according to claim 1, characterized in that: The temperature of the mixed reaction is 50-80°C, the rotation speed is 100-250 r / min, and the time is 0.5-1.5 h.

3. The aqueous polyurethane with long-lasting antifouling performance according to claim 1, characterized in that: The quaternary ammonium salt is any one of hexadecyldimethylammonium chloride, methylbenzenedimethylammonium chloride and trimethylammonium bromide.

4. The aqueous polyurethane with long-lasting antifouling performance according to claim 1, characterized in that: The fatty acid is any one of n-octanoic acid, n-nonanoic acid, n-decanoic acid and lauric acid.

5. The aqueous polyurethane with long-lasting antifouling performance according to claim 1, characterized in that: The cross-linking agent is any one of KU-550, A-1100, Z-6011, KBE-903, and GF93.

6. The aqueous polyurethane with long-lasting antifouling performance according to claim 1, characterized in that: The polypropylene carbonate monool is any one of polycarbonate diol and polycarbonate 1,6-hexanediol.

7. The waterborne polyurethane with long-lasting antifouling performance according to claim 1, characterized in that: The diisocyanate is any one of isophorone diisocyanate and hexamethylene diisocyanate.

8. The waterborne polyurethane with long-lasting antifouling performance according to claim 1, characterized in that: The tertiary amine compound is any one of triethylamine, dimethylethylamine, methyldiethanolamine and methyldiethylamine.

9. A method for preparing a waterborne polyurethane having long-lasting antifouling properties according to any one of claims 1 to 8, characterized in that: The hydrophobic solvent is gradually polymerized with polypropylene carbonate polyol, diisocyanate, a crosslinking agent and a tertiary amine compound, and then dispersed in deionized water.

10. Use of the waterborne polyurethane having long-lasting antifouling properties as claimed in any one of claims 1 to 8 in leather finishing.