Waterproof and stain-resistant fabric and method of making the same

Abstract

The application discloses a waterproof and stain-resistant fabric and a preparation method thereof. The waterproof and stain-resistant fabric comprises a fabric substrate and a waterproof and stain-resistant layer, and is characterized in that the waterproof and stain-resistant layer is prepared from a mass ratio of (0.55-0.7):1 of a dual-repellent coating and a precoating; the dual-repellent coating comprises the following raw materials in parts by weight: perfluoroalkyl alcohol 12-24 parts; polyisocyanate 12-24 parts; the precoating comprises the following raw materials in parts by weight: thiol-containing water-based adhesive 30-40 parts; epoxy silane oligomer 12-18 parts; and the waterproof and stain-resistant layer is obtained by sequentially coating the precoating and the dual-repellent coating on the surface of the fabric substrate and then drying. The waterproof and stain-resistant fabric prepared by the application has excellent waterproof and stain-resistant performance and good durability.

Description

Technical Field

[0001] This application relates to the field of waterproof and stain-resistant fabrics, and in particular to a waterproof and stain-resistant fabric and its preparation method. Background Technology

[0002] Water, oil, and stains can cause a lot of trouble for people when they get on fabrics, affecting their health and living environment. Therefore, waterproofing and stain-resistant finishing of fabrics is of great importance.

[0003] Commonly used pollution-free, waterproof, and stain-resistant technologies include the use of silicate material coatings, biomimetic anti-fouling technology, and the use of low surface energy anti-fouling materials. Among them, low surface energy material coatings utilize the low surface energy of the coating to possess strong non-stick properties, making it difficult for most substances to adhere to the coating surface. They are both hydrophobic and oleophobic, and have significant research value.

[0004] Currently, waterproof and stain-resistant finishes typically employ low surface energy materials, including silicone rubber-based coatings, silicone resin-based coatings, and fluorine-based antifouling coatings. Silicone rubber-based coatings are gradually being phased out due to poor adhesion and excessive susceptibility to environmental factors during curing. Silicone resin-based coatings also suffer from poor adhesion, low strength, and susceptibility to damage in water. Fluorine-based antifouling coatings, containing trifluoromethyl groups, possess very low surface energy, theoretically making them excellent waterproof and stain-resistant materials. However, they also suffer from poor adhesion, and their waterproof and stain-resistant capabilities have not met expectations, resulting in a decrease in both the durability and waterproof / stain-resistant performance of the fabric. Summary of the Invention

[0005] To address the issues of poor durability and insufficient waterproof and stain-resistant properties of waterproof and stain-resistant fabrics, this application provides a waterproof and stain-resistant fabric and its preparation method.

[0006] In a first aspect, this application provides a waterproof and stain-resistant fabric, comprising a fabric substrate and a waterproof and stain-resistant layer, wherein the waterproof and stain-resistant layer is prepared from a dual-repellent coating and a pre-coating in a mass ratio of (0.55-0.7):1; the dual-repellent coating comprises the following raw materials in parts by weight:

[0007] 12-24 parts of perfluoroalkyl alcohols;

[0008] 12-24 parts of polyisocyanate;

[0009] The pre-coating comprises the following raw materials in parts by weight:

[0010] 30-40 parts of a mercapto-containing aqueous adhesive;

[0011] 12-18 parts of epoxy silane oligomer;

[0012] The waterproof and stain-resistant layer is obtained by sequentially applying a pre-coating and a dual-repellent coating to the surface of the fabric substrate and then drying it.

[0013] Perfluoroalkyl alcohols contain abundant trifluoromethyl groups, resulting in very low surface energy and excellent waterproof and stain-resistant properties. However, due to their extremely low surface energy, while water and dirt struggle to adhere to their surfaces, ordinary adhesives also fail to provide a strong bond between them and the fabric substrate. This application first reacts a perfluoroalkyl alcohol with a polyisocyanate, whereby the active hydroxyl groups on the perfluoroalkyl alcohol undergo an addition reaction with one of the isocyanate groups in the polyisocyanate, thus attaching the trifluoromethyl group to the polyisocyanate. The epoxy-based silane oligomer can then be linked to other isocyanate groups in the polyisocyanate through its abundant hydroxyl groups, and further linked through a reaction between the epoxy groups and the thiol groups in a mercapto-containing aqueous adhesive. By employing this technical solution, the trifluoromethyl group, which is difficult to adhere to the surface, is firmly bonded to the adhesive through the connections between these groups. The adhesive, with its abundant active groups, adheres well to the fabric substrate, allowing the waterproof and stain-resistant material to better adhere to the fabric and improving the durability of the waterproof and stain-resistant fabric.

[0014] The reason why current waterproof and stain-resistant materials fail to achieve the expected waterproof and stain-resistant performance is that too many non-low surface energy groups are added to the coating, thus increasing the overall surface energy of the coating and affecting the waterproof and stain-resistant performance of the fabric. This application uses epoxy-based silane oligomers, which can not only use their hydroxyl and epoxy groups to connect the dihydrophobic coating and mercapto-containing water-based adhesive to themselves, enhancing the adhesion of the waterproof and stain-resistant material to the fabric substrate surface, but also, as an organosilicon material, epoxy-based silane oligomers have very low surface energy. Replacing part of the adhesive with them can reduce the content of non-low surface energy materials, lower the overall surface energy of the waterproofing additive, and increase the waterproof and stain-resistant ability of the fabric.

[0015] Preferably, the mass ratio of perfluoroalkyl alcohol to polyisocyanate is (15-20):(15-20).

[0016] By adopting the above technical solution, while ensuring that isocyanate groups and hydroxyl groups can generate urethane groups to link perfluoroalkyl alcohols and polyisocyanates together, it is possible to maximize the presence of more unreacted isocyanate groups in the mixture for linking with hydroxyl groups in epoxy silane oligomers, thereby improving the cohesive strength of the water-resistant additive and enhancing the durability of the waterproof and stain-resistant fabric.

[0017] Preferably, the dual-hydrophobic coating further comprises 0.5-2 parts of a tertiary amine accelerator; the tertiary amine accelerator includes at least one of 2,4,6-tris(dimethylaminomethyl)phenol, triethylenediamine, and benzyldimethylamine.

[0018] By employing the above technical solution, the ring-opening reaction between epoxy groups and mercapto groups in the pre-coating can be promoted, increasing the degree of reaction and the tightness of the bond. Epoxy silane oligomers belong to aliphatic epoxy compounds. The stereostructure of aliphatic epoxy compounds differs significantly from that of terminal epoxy compounds. The epoxy groups in aliphatic epoxy compounds are subject to a certain degree of steric hindrance, resulting in much lower reactivity compared to the epoxy groups in terminal epoxy compounds. The tertiary amine promoter used in this application is a nucleophile. When it approaches the epoxy silane oligomer, it attacks the carbon atom, causing the carbon-oxygen bond to break, thus opening the epoxy ring and allowing for better reaction with the mercapto groups. This improves the adhesive strength between the epoxy silane oligomer and the adhesive, increasing the durability of the fabric.

[0019] Preferably, the method for preparing the epoxy silane oligomer includes the following steps:

[0020] Hydrolysis: The epoxy silane is heated to 60-80℃ and a mixed solution of water and short-chain alcohol is added dropwise to obtain the hydrolysis product;

[0021] Polymerization: The hydrolysis product is heated to 110-120℃ and reacted for 1.5-2 hours. The short-chain alcohol is recovered by vacuum distillation. The temperature is then raised to 130-140℃ and reacted for 2.5-3 hours to obtain epoxy silane oligomers.

[0022] More preferably, the short-chain alcohol is methanol or ethanol.

[0023] By adopting the above technical solution, epoxy silanes are hydrolyzed and self-polymerized into epoxy silane oligomers, which contain a higher density of epoxy groups. When the same number of isocyanate groups are connected, more epoxy groups can be connected at the other end, which improves the bonding ability to waterproof and stain-resistant materials and improves the durability of waterproof and stain-resistant fabrics.

[0024] Preferably, the mercapto-containing aqueous adhesive is obtained by reacting an aqueous resin and sodium trithiocyanate at a mass ratio of (8-10):(0.8-1.2) at 140-160°C for 20-40 minutes; the aqueous resin contains carbon-carbon double bonds.

[0025] Sodium trithiocyanate has three active thiol functional groups. These thiol groups can first react with the double bonds in the waterborne resin at 140-160℃ to form cross-linked covalent bonds, increasing the bonding strength between the two. Then, these active thiol groups can undergo ring-opening addition reactions with the epoxy groups in the epoxy silane oligomer, firmly linking the adhesive and the epoxy silane oligomer, enhancing the adhesive strength of the water-resistant additive and improving the fabric's durability.

[0026] More preferably, the waterborne resin includes at least one of waterborne acrylate and waterborne polyurethane resin.

[0027] Preferably, the perfluoroalkyl alcohol has 6-10 carbon atoms.

[0028] By adopting the above technical solution, fluorine atoms can fully cover the fabric surface without compromising the overall waterproof and stain-resistant properties of the fabric due to excessive CF2 groups. Fluorine atoms in the material are linked by long-chain carbon atoms, hydroxyl groups, and isocyanate groups, which are then connected to the adhesive. Too short a carbon chain will prevent fluorine atoms from fully covering the fabric surface. The surface tension of CF2 groups is 18 mN / m, while that of CF3 groups is 6.7 mN / m. It can be seen that the surface energy of CF2 groups is much greater than that of CF3 groups, meaning that the waterproof and stain-resistant ability of CF2 groups is much lower than that of CF3 groups. When the carbon chain lengthens, the number of CF3 groups remains constant, while the number of CF2 groups increases accordingly. Therefore, excessively long carbon chains lead to a higher content of CF2 groups, resulting in an overall increase in the surface energy of the water-resistant additives and a decrease in the waterproof and stain-resistant properties of the fabric.

[0029] Preferably, the preparation method of the dual-hydrophobic coating includes the following steps: under nitrogen atmosphere, a perfluoroalkyl alcohol is dissolved in an organic solvent, and a polyisocyanate is added, the temperature is raised to 80-90°C, and the reaction is carried out for 4-5 hours to obtain the dual-hydrophobic coating.

[0030] By employing the above technical solution, perfluoroalkyl alcohols and polyisocyanates can undergo a stable addition reaction and interconnect in nitrogen. The isocyanate group is a highly unsaturated group with very high chemical reactivity, capable of reacting with any compound containing an active hydrogen atom; the hydroxyl group in the perfluoroalkyl alcohol can react and connect with it. However, during this reaction, all substances are easily affected by moisture in the air, so nitrogen is needed to protect the reaction and ensure its stable progress.

[0031] Preferably, the preparation method of the pre-coating includes the following steps: mixing epoxy silane oligomers and mercapto-containing aqueous adhesives, adding tertiary amine accelerators, stirring evenly, and reacting for 0.5-2 hours to obtain the pre-coating.

[0032] By adopting the above technical solution, the epoxy and mercapto groups in the epoxy silane oligomer can react first to form a thioether bond. The thioether bond has good stability and can effectively combine the epoxy silane oligomer with the adhesive.

[0033] When the raw materials do not contain tertiary amine accelerators, the corresponding preparation steps also do not require the addition of tertiary amine accelerators; the reaction can be carried out directly by stirring.

[0034] Secondly, this application provides a method for preparing a waterproof and stain-resistant fabric, comprising the following steps:

[0035] S1: Apply the pre-coating material to the fabric substrate to obtain a pre-coated fabric;

[0036] S2: Apply the dual-repellent coating to the surface of the pre-coated fabric, then dry and set it to obtain a waterproof and stain-resistant fabric.

[0037] By employing the above technical solution, under the action of a thiol-containing adhesive, a water-resistant and stain-resistant material with low surface energy can be firmly adhered to the surface of the fabric substrate. This application employs a step-by-step finishing process: first, a pre-coating is applied to the surface of the fabric substrate to form a pre-coating layer; then, a bi-repellent coating is applied to the pre-coating layer. This prevents the CF3 groups, which have the lowest surface energy, from directly contacting the fabric substrate, leaving them exposed. This not only allows for a more complete utilization of the water-resistant and stain-resistant properties of the fluorine atoms but also prevents the problem of insufficient adhesion to the fabric substrate surface caused by the low surface energy of the CF3 groups, thus improving the durability of the water-resistant and stain-resistant fabric.

[0038] In summary, this application has the following beneficial effects:

[0039] 1. This application uses multiple isocyanate groups in a polyisocyanate to link with hydroxyl groups in a perfluoroalkyl alcohol and an epoxy silane oligomer, respectively, and then reacts the epoxy groups in the epoxy silane oligomer with the thiol groups in a mercapto-containing aqueous adhesive to bond a low surface energy waterproof and stain-resistant material that is difficult to adhere to the surface of an object to the surface of a fabric substrate.

[0040] 2. This application uses waterborne acrylate and sodium trithiocyanate as a mercapto-containing waterborne adhesive. Sodium trithiocyanate contains three active mercapto groups, which can undergo a vulcanization reaction with the double bonds in the waterborne acrylate to generate cross-linked covalent bonds, resulting in good fusion with the adhesive. This allows the adhesive to contain abundant mercapto groups that can combine with the epoxy groups in the epoxy silane copolymer, helping to connect the dual-repellent coating and the pre-coating, thus giving the fabric dual-repellent properties.

[0041] 3. By applying the waterproofing agent to the fabric substrate surface in steps, this application allows the low surface energy CF3 groups with anti-fouling ability to be located on the outside, thus better exerting the waterproof and anti-fouling effect. Furthermore, by preventing the agent from directly contacting the fabric substrate surface, it can also better adhere to the fabric substrate through chemical bonds, thereby improving the durability of the waterproof and anti-fouling fabric. Detailed Implementation

[0042] The aqueous acrylate used in the preparation examples or embodiments of this application was prepared using Jilong Chemical CTD-6070.

[0043] Example of pre-coating preparation

[0044] Preparation Example 1-1: A pre-coating was prepared according to the following steps:

[0045] Preparation of mercapto-containing aqueous adhesive: 50g of monosodium trithiocyanate was added to 500g of aqueous acrylate and heated to 160℃ for 30 minutes to obtain mercapto-containing aqueous adhesive.

[0046] Preparation of epoxy silane oligomers: 300g of epoxy trimethoxysilane was dissolved in methanol solution, heated to 70℃, and a mixture of 40g water and 20g methanol was added dropwise for hydrolysis. After obtaining the hydrolysis product, the temperature was further increased to 110℃, and after 2 hours, the methanol was recovered by vacuum distillation. The temperature was then further increased to 130℃, and after 4 hours, epoxy silane oligomers were obtained.

[0047] Pre-coating preparation: Add 250g of epoxy silane oligomer to 550g of mercapto-containing aqueous adhesive and stir for 1 hour to obtain the pre-coating.

[0048] Preparation Examples 1-2: A pre-coating was prepared according to the following steps:

[0049] Preparation of mercapto-containing aqueous adhesive: 60g of monosodium trithiocyanate was added to 460g of aqueous acrylate and heated to 160℃ for 30 minutes to obtain mercapto-containing aqueous adhesive.

[0050] Preparation of epoxy silane oligomers: 300g of epoxy trimethoxysilane was dissolved in methanol solution, heated to 70℃, and a mixture of 40g water and 20g methanol was added dropwise for hydrolysis. After obtaining the hydrolysis product, the temperature was further increased to 110℃, and after 2 hours, the methanol was recovered by vacuum distillation. The temperature was then further increased to 130℃, and after 4 hours, epoxy silane oligomers were obtained.

[0051] Pre-coating preparation: Add 300g of epoxy silane oligomer to 520g of mercapto-containing aqueous adhesive and stir for 1 hour to obtain the pre-coating.

[0052] Preparation Examples 1-3: A pre-coating was prepared according to the following steps:

[0053] Preparation of mercapto-containing aqueous adhesive: 40g of monosodium trithiocyanate was added to 600g of aqueous acrylate and heated to 160℃ for 30 minutes to obtain mercapto-containing aqueous adhesive.

[0054] Preparation of epoxy silane oligomers: 300g of epoxy trimethoxysilane was dissolved in methanol solution, heated to 70℃, and a mixture of 40g water and 20g methanol was added dropwise for hydrolysis. After obtaining the hydrolysis product, the temperature was further increased to 110℃, and after 2 hours, the methanol was recovered by vacuum distillation. The temperature was then further increased to 130℃, and after 4 hours, epoxy silane oligomers were obtained.

[0055] Pre-coating preparation: 200g of epoxy silane oligomer was added to 640g of mercapto-containing aqueous adhesive, and the mixture was stirred for 1 hour to obtain the pre-coating.

[0056] Preparation Examples 1-4, a pre-coating, differ from Preparation Example 1 in that the epoxy silane oligomer preparation step is omitted, and an equal amount of epoxy trimethoxysilane is used instead of epoxy silane oligomer in the pre-coating preparation step.

[0057] Preparation Examples 1-5, a pre-coating, differs from Preparation Example 1 in that 160g of mercapto-based polyethylene glycol acrylate (Guangzhou Carbon Water Technology Co., Ltd. 80030807, mercapto-substitution rate 95%) is used instead of 550g of mercapto-containing aqueous adhesive in the pre-coating preparation step.

[0058] Preparation Examples 1-6, a pre-coating, differ from Preparation Example 1 in that 10g of 2,4,6-tris(dimethylaminomethyl)phenol is added during the pre-coating preparation step.

[0059] Preparation Examples 1-7, a pre-coating, differ from Preparation Example 1 in that an equal amount of waterborne acrylate is used instead of a mercapto-containing waterborne adhesive in the pre-coating raw materials.

[0060] Preparation Examples 1-8, a pre-coating, differ from Preparation Example 1 in that the epoxy silane oligomer preparation step is omitted, and an equal amount of waterborne epoxy resin (epoxy equivalent 170-220 g / mol, viscosity 300-2000 mPas) is used instead of epoxy silane oligomer in the pre-coating preparation step.

[0061] Example of preparation of dual-repellent coating

[0062] Preparation Example 2-1: A dual-repellent coating was prepared according to the following steps: 10g of perfluorooctyl ethyl alcohol was placed in a three-necked flask, vacuumed, heated to 70°C and held for 2 hours, cooled down, and nitrogen gas was introduced to make the perfluorooctyl ethyl alcohol in the flask an anhydrous and oxygen-free environment. 250g of ethyl acetate and 10g of diisocyanate were added, stirred and heated to 85°C, and reacted for five hours to obtain the dual-repellent coating.

[0063] Preparation Example 2-2: A dual-repellent coating was prepared according to the following steps: 7g of perfluorooctyl ethyl alcohol was placed in a three-necked flask, vacuumed, heated to 70°C and held for 2 hours, cooled down, and nitrogen gas was introduced to make the perfluorooctyl ethyl alcohol in the flask an anhydrous and oxygen-free environment. 250g of ethyl acetate and 14g of diisocyanate were added, stirred and heated to 85°C, and reacted for five hours to obtain the dual-repellent coating.

[0064] Preparation Example 2-3: A dual-repellent coating was prepared according to the following steps: 14g of perfluorooctyl ethyl alcohol was placed in a three-necked flask, vacuumed, heated to 70°C and held for 2 hours, cooled down, and nitrogen gas was introduced to make the perfluorooctyl ethyl alcohol in the flask an anhydrous and oxygen-free environment. 250g of ethyl acetate and 7g of diisocyanate were added, stirred and heated to 85°C, and reacted for five hours to obtain the dual-repellent coating.

[0065] Preparation Example 2-4, a dual-hydrophobic coating, differs from Preparation Example 2-1 in that an equal amount of perfluorobutyl ethyl alcohol is used instead of perfluorooctyl ethyl alcohol.

[0066] Preparation Example 2-5, a dual-hydrophobic coating, differs from Preparation Example 2-1 in that an equal amount of perfluorododecanoic acid is used instead of perfluorooctylethyl alcohol.

[0067] Preparation Example 2-6, a dual-hydrophobic coating, differs from Preparation Example 2-1 in that the amount of perfluorooctyl ethyl alcohol used in the step is 40g.

[0068] Preparation Example 2-7, a dual-hydrophobic coating, differs from Preparation Example 2-1 in that the amount of diisocyanate used in the step is 40g.

[0069] Preparation Examples 2-8: A waterproof and stain-resistant coating was prepared by the following steps: waterborne polyurethane, octafluoropentyl acrylate, azobisisobutyronitrile and acetone were mixed, nitrogen gas was introduced, and the mixture was heated to 80°C for 6 hours to obtain the waterproof and stain-resistant coating.

[0070] Example

[0071] Example 1: A waterproof and stain-resistant fabric was prepared according to the following steps:

[0072] S1: The pre-coating material obtained in Preparation Example 1-1 was applied to the fabric substrate by roller coating to obtain a coating amount of 10±1 g / m. 2 Pre-coated fabric;

[0073] S2: The dual-repellent coating obtained in Preparation Example 2-1 was applied to the surface of the pre-coated fabric by roller coating, with a coating amount of 6 ± 0.5 g / m². 2 Then, the fabric is dried and set at temperatures of 90℃ and 120℃ respectively, resulting in a waterproof and stain-resistant fabric.

[0074] Example 2: A waterproof and stain-resistant fabric was prepared according to the following steps:

[0075] S1: The pre-coating material obtained in Preparation Examples 1-2 was applied to the fabric substrate by roller coating to obtain a coating amount of 10±1 g / m. 2 Pre-coated fabric;

[0076] S2: The dual-repellent coating obtained in Preparation Example 2-2 was applied to the surface of the pre-coated fabric by roller coating. The coating amount of the dual-repellent coating was 6.5 ± 0.5 g / m². 2 Then, the fabric is dried and set at temperatures of 90℃ and 120℃ respectively, resulting in a waterproof and stain-resistant fabric.

[0077] Example 3: A waterproof and stain-resistant fabric was prepared according to the following steps:

[0078] S1: The pre-coatings obtained in Preparation Examples 1-3 were applied to the fabric substrate by roller coating to obtain a coating weight of 10±1 g / m. 2 Pre-coated fabric;

[0079] S2: The dual-repellent coating obtained in Preparation Examples 2-3 was applied to the surface of the pre-coated fabric by roller coating, with a coating amount of 5.5 ± 0.5 g / m². 2 Then, the fabric is dried and set at temperatures of 90℃ and 120℃ respectively, resulting in a waterproof and stain-resistant fabric.

[0080] Example 4, a waterproof and stain-resistant fabric, differs from Example 1 in that, in step S1, an equal amount of the pre-coating material prepared in Preparation Examples 1-4 is used instead of the pre-coating material prepared in Preparation Example 1-1.

[0081] Example 5, a waterproof and stain-resistant fabric, differs from Example 1 in that, in step S1, an equal amount of the pre-coating material prepared in Preparation Examples 1-5 is used instead of the pre-coating material prepared in Preparation Example 1-1.

[0082] Example 6, a waterproof and stain-resistant fabric, differs from Example 1 in that, in step S1, an equal amount of the pre-coating material prepared in Preparation Examples 1-6 is used instead of the pre-coating material prepared in Preparation Example 1-1.

[0083] Example 7, a waterproof and stain-resistant fabric, differs from Example 1 in that, in step S2, an equal amount of the dihydrophobic coating obtained in Preparation Example 2-4 is used instead of the dihydrophobic coating obtained in Preparation Example 2-1.

[0084] Example 8, a waterproof and stain-resistant fabric, differs from Example 1 in that, in step S2, an equal amount of the dihydrophobic coating obtained in Preparation Example 2-5 is used instead of the dihydrophobic coating obtained in Preparation Example 2-1.

[0085] Example 9, a waterproof and stain-resistant fabric, differs from Example 1 in that, in step S2, an equal amount of the dihydrophobic coating obtained in Preparation Example 2-6 is used instead of the dihydrophobic coating obtained in Preparation Example 2-1.

[0086] Example 10, a waterproof and stain-resistant fabric, differs from Example 1 in that, in step S2, an equal amount of the dihydrophobic coating obtained in Preparation Example 2-7 is used instead of the dihydrophobic coating obtained in Preparation Example 2-1.

[0087] Comparative Example

[0088] Comparative Example 1: A waterproof and stain-resistant fabric was prepared according to the following steps: The waterproof and stain-resistant coatings obtained in Preparation Examples 2-8 were applied to the surface of the fabric substrate by roller coating, with a coating amount of 16.5 ± 1 g / m². 2 Then, it is dried and shaped at temperatures of 90℃ and 120℃ respectively, to obtain a waterproof and stain-resistant fabric.

[0089] Comparative Example 2, a waterproof and stain-resistant fabric, differs from Example 8 in that, in step S1, an equal amount of the pre-coating obtained in Preparation Examples 1-7 is used instead of the pre-coating obtained in Preparation Example 1-1.

[0090] Comparative Example 3, a waterproof and stain-resistant fabric, differs from Example 8 in that, in step S1, an equal amount of the pre-coating obtained in Preparation Examples 1-8 is used instead of the pre-coating obtained in Preparation Example 1-1.

[0091] Performance testing

[0092] Experiment 1: Waterproof performance test method: The waterproof performance of the examples and comparative examples was tested according to AATCC 22-2017 "Water repellency test of textiles - spray method". The test was repeated after 50 washes. The results are shown in Table 1.

[0093] Test 2: Oil Repellency Test Method: The oil repellency of the examples and comparative examples was tested according to AATCC 118-2020 "Textiles - Test for Oil Repellency and Hydrocarbon Resistance". The test was repeated after 50 washes. The results are shown in Table 1.

[0094] Test 3: Stain Resistance Test Method: The stain resistance of the examples and comparative examples was tested according to GB / T30159.1-2013 "Textiles - Test and Evaluation of Stain Resistance - Part 1: Stain Resistance". The test was repeated after 50 washes. The results are shown in Table 1.

[0095] Table 1. Test Results of Waterproof and Stain-Resistant Fabric Waterproof and Stain-Resistant Performance

[0096]

[0097]

[0098] Analysis of experimental results:

[0099] 1. As can be seen from Examples 1-10 and Comparative Examples 1-3, and Table 1, this application effectively adheres fluorine atoms, a low surface energy waterproof and stain-resistant material, to the surface of the fabric substrate using polyisocyanate, epoxy silane oligomer, and a mercapto-containing aqueous adhesive. This may be because the hydroxyl group in the perfluoroalkyl alcohol containing the fluorine atom first connects to an isocyanate group in the polyisocyanate, followed by connections between the other isocyanate groups and the hydroxyl groups in the epoxy silane oligomer. The epoxy groups in the epoxy silane oligomer can then connect to the mercapto groups in the mercapto-containing aqueous adhesive. The adhesive, with its numerous active groups, adheres to the fabric substrate, alleviating the problem of low surface energy materials being difficult to adhere to fabrics due to their low surface energy, thus improving the durability of the waterproof and stain-resistant fabric.

[0100] 2. As can be seen from Examples 1-6, Examples 9-10, and Comparative Example 2, and in conjunction with Table 1, this application strengthens the bonds between chemical bonds by hydrolyzing and polymerizing epoxy silanes into oligomers, using sodium trifluoroalkyl alcohol, promoting the reaction between the epoxy silane oligomers and the mercapto-containing aqueous adhesive, and controlling the ratio of perfluoroalkyl alcohol to polyisocyanate, thus making the fluorine atoms adhere more stably to the fabric surface. This is likely because hydrolyzing and polymerizing epoxy silanes into oligomers reduces their hydroxyl groups, resulting in fewer isocyanate groups attached to each epoxy group, making it more stable; sodium trifluoroalkyl alcohol has more and more reactive mercapto groups that can react with epoxy groups, and the tertiary amine accelerator promotes this reaction; controlling the ratio of perfluoroalkyl alcohol to polyisocyanate prevents excessive consumption of isocyanate groups, improves the bond strength between chemical bonds, and enhances the durability of the waterproof and stain-resistant fabric.

[0101] 3. As can be seen from Examples 1 and 7-8, and Table 1, this application achieves better waterproof and stain-resistant properties for waterproof and stain-resistant fabrics by using perfluoroalkyl alcohols with 6-10 carbon atoms. This may be because a carbon chain that is too short will prevent fluorine atoms from covering the entire fabric surface, while a carbon chain that is too long will increase the content of CF2 groups, weakening the performance of the waterproofing agent and reducing the waterproof and stain-resistant properties of the fabric.

[0102] 4. As can be seen from Example 1 and Comparative Example 3, and in conjunction with Table 1, this application, through the use of epoxy-based silane oligomers, not only better connects the mercapto-containing waterborne adhesive and the dual-repellent coating, but also improves the waterproof and stain-resistant properties of the water-resistant additives. This may be because the epoxy and hydroxyl groups contained in the epoxy-based silane oligomers can respectively connect mercapto and isocyanate groups, and since epoxy-based silane oligomers belong to organosilicon and have very low surface energy, their addition can increase the content of low surface energy substances in the water-resistant additives, thereby improving the waterproof and stain-resistant capabilities of the water-resistant additives and enhancing the waterproof and stain-resistant properties of the waterproof and stain-resistant fabric.

[0103] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A waterproof and stain-resistant fabric, comprising a fabric substrate and a waterproof and stain-resistant layer, characterized in that, The waterproof and stain-resistant layer is prepared from a dual-repellent coating and a pre-coating with a mass ratio of (0.55-0.7):1; the dual-repellent coating comprises the following raw materials in parts by weight: 12-24 parts of perfluoroalkyl alcohols; 12-24 parts of polyisocyanate; The pre-coating comprises the following raw materials in parts by weight: 30-40 parts of a mercapto-containing aqueous adhesive; 12-18 parts of epoxy silane oligomer; The waterproof and stain-resistant layer is obtained by sequentially applying a pre-coating and a dual-repellent coating to the surface of the fabric substrate and then drying it. The method for preparing the epoxy-based silane oligomer includes the following steps: Hydrolysis: The epoxy silane is heated to 60-80℃ and a mixed solution of water and short-chain alcohol is added dropwise to obtain the hydrolysis product; Polymerization: The hydrolysis product is heated to 110-120℃ and reacted for 1.5-2 hours. The short-chain alcohol is recovered by vacuum distillation. The temperature is then raised to 130-140℃ and reacted for 2.5-3 hours to obtain epoxy silane oligomers. The mercapto-containing aqueous adhesive is obtained by reacting an aqueous resin and sodium trithiocyanate at a mass ratio of (8-10):(0.8-1.2) at 140-160°C for 20-40 minutes; the aqueous resin contains carbon-carbon double bonds.

2. The waterproof and stain-resistant fabric according to claim 1, characterized in that, The mass ratio of the perfluoroalkyl alcohol to the polyisocyanate is (15-20):(15-20).

3. The waterproof and stain-resistant fabric according to claim 1, characterized in that, The dual-hydrophobic coating also includes 0.5-2 parts of a tertiary amine accelerator; the tertiary amine accelerator includes at least one of 2,4,6-tris(dimethylaminomethyl)phenol, triethylenediamine, and benzyldimethylamine.

4. The waterproof and stain-resistant fabric according to claim 1, characterized in that, The perfluoroalkyl alcohol has 6-10 carbon atoms.

5. The waterproof and stain-resistant fabric according to claim 2, characterized in that, The preparation method of the dual-hydrophobic coating includes the following steps: under nitrogen atmosphere, a perfluoroalkyl alcohol is dissolved in an organic solvent, and a polyisocyanate is added. The temperature is raised to 80-90℃, and the reaction is carried out for 4-5 hours to obtain the dual-hydrophobic coating.

6. The waterproof and stain-resistant fabric according to claim 1, characterized in that, The preparation method of the pre-coating includes the following steps: mixing epoxy silane oligomers and mercapto-containing aqueous adhesives, adding tertiary amine accelerators, stirring evenly, and reacting for 0.5-2 hours to obtain the pre-coating.

7. The method for preparing the waterproof and stain-resistant fabric according to any one of claims 1-6, characterized in that, Includes the following steps: S1: Apply the pre-coating material to the fabric substrate to obtain a pre-coated fabric; S2: Apply the dual-repellent coating to the surface of the pre-coated fabric, then dry and set it to obtain a waterproof and stain-resistant fabric.

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