Waterproof and moistureproof coating for flexible fabric as well as preparation method and application of waterproof and moistureproof coating

Abstract

The invention discloses a waterproof and moistureproof coating for a flexible fabric as well as a preparation method and application thereof, and relates to the technical field of hydrophobic coatings. The method comprises the following steps: preparing modified nano silicon dioxide and mesoporous silicon dioxide; the preparation method comprises the following steps: uniformly dispersing modified nano silicon dioxide and mesoporous silicon dioxide in an organic solvent, adding organic silicon resin, and uniformly mixing to obtain a composite coating; carrying out hydrophobic modification on the PET fabric; and coating the hydrophobic modified PET fabric with the composite coating to obtain the waterproof and moistureproof coating on the PET fabric. According to hydrophobic modification of the PET fabric, the waterproof and moistureproof coating is combined with the super-hydrophobic coating, so that the waterproof and moistureproof performance of the PET fabric is improved, and the excellent mechanical property of the PET fabric is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of hydrophobic coatings, and in particular to a waterproof and moisture-proof coating for flexible fabrics, a preparation method and an application thereof. Background Art

[0002] PET fabric has excellent mechanical and thermal properties, as well as low cost. It plays an indispensable role in modern life and work and has a very broad development prospect.

[0003] Waterproof and moisture-proof coatings are widely used in fabric protection. As a protective barrier, the coating has good water vapor barrier properties. The construction of waterproof and moisture-proof coatings mainly includes sol-gel method, dip coating method, spray coating method, template method, chemical vapor deposition (CVD), etc. Theoretically, the combination of low surface energy chemistry and nano / micron-level hierarchical roughness is a prerequisite for achieving superoleophobic surfaces. Therefore, people usually use fillers that can provide ideal surface roughness, including SiO2, TiO2, ZnO, etc., and add fluorinated compounds as low surface energy components for modification. SiO2 / polymer nanocomposites enhance the barrier properties of fabrics in the form of coatings.

[0004] The structure of silicone resin consists of a Si-O-Si main chain and side chains of organic groups (-R, -CH3, -CH2CH3, etc.) bonded to silicon atoms (Si) in the main chain. Under conditions such as heating or catalysis, the resin transforms to form a coating with a three-dimensional cross-linked network structure. Silicone resin coatings are easy to process, have low curing temperatures, low costs, and have excellent weather resistance, hydrophobicity, chemical resistance, and electrical insulation. They are often used as film-forming materials for the preparation of waterproof and moisture-proof coatings.

[0005] Flexible fabric coatings in the prior art cannot prevent the penetration of liquid or gaseous water for a long time in a high humidity environment. The prior art can only provide waterproof function, but cannot meet the requirements of waterproof and moisture-proof performance in practical applications. The existing coatings are prone to wear or tear when repeatedly used or subjected to external forces, which affects their function and life. Summary of the invention

[0006] In view of the deficiencies in the above-mentioned background technology and in order to improve the waterproof and moisture-proof properties of the fabric, the present invention uses an environmentally friendly methyl-containing water-based silicone resin (SH) as a film-forming substance for the coating, and uses hydrophobically modified nano-silicon dioxide (NS) and mesoporous silica (MS) as fillers to prepare a flexible coating. The coating can not only form a dense hydrophobic coating on the surface of the PET fabric, but also improve the roughness of the coating surface, which can effectively prevent the penetration of liquid water. The silica particles in the coating extend the permeation path of gaseous water, thereby effectively improving its moisture-proof properties. On this basis, the PET fabric is further combined with the hydrophobic modification, and the waterproof and moisture-proof properties of the fabric are improved from multiple dimensions. This research is of great significance to the use and storage of flexible fabrics in high humidity environments.

[0007] The present invention provides a waterproof and moisture-proof coating for flexible fabrics, a preparation method and an application thereof, which combines a hydrophobically modified PET fabric with a waterproof and moisture-proof coating. By introducing a hydrophobic structure on the PET surface and coating the surface with a micro-nano particle / organic silicon hydrophobic moisture-proof coating, the fabric is endowed with excellent mechanical and waterproof and moisture-proof properties.

[0008] The first object of the present invention is to provide a method for preparing a waterproof and moisture-proof coating for flexible fabrics, comprising the following steps: Preparation of modified nano-silica and mesoporous silica; The modified nano-silicon dioxide and mesoporous silicon dioxide are uniformly dispersed in an organic solvent, and then an organic silicon resin is added and mixed uniformly to obtain a composite coating; Hydrophobic modification of PET fabric; The composite coating is coated on the hydrophobically modified PET fabric, so that a waterproof and moisture-proof coating is prepared on the PET fabric.

[0009] Preferably, in the composite coating, the mass ratio of the modified nano-silica to the mesoporous silica is 1:1-2; and the amount of the organic silicone resin added is 20-60 wt%.

[0010] Preferably, the modified nano-silica includes methylated nano-silica or fluoromethylated nano-silica.

[0011] Preferably, nano-silica is uniformly dispersed in anhydrous ethanol, TMCS or TFTES is added, and condensed and refluxed at 75-85° C. for 2-4 h, and then filtered, washed, dried, and ground to obtain methylated nano-silica or fluoromethylated nano-silica.

[0012] Preferably, the mesoporous silica is prepared according to the following steps: Jeffamine D2000 surfactant was dissolved in anhydrous ethanol, and then water solvent was added and mixed to obtain a surfactant solution; uniformly dispersing TEOS in a surfactant solution to obtain a mixture; The mixture is aged for 20 to 24 hours, filtered and dried, and then calcined in air at 550 to 650° C. for 3 to 5 hours to obtain mesoporous silica.

[0013] Preferably, the PET fabric is hydrophobically modified, comprising: immersing the PET fabric in a 0.5-1 mol / L NaOH solution for 2-4 h, adding the fabric to anhydrous ethanol after washing and drying, and then adding TMCS or TFTES with stirring, condensing and refluxing at 75-85° C. for 2-4 h, and then washing and drying to obtain the hydrophobically modified PET fabric.

[0014] Preferably, after the composite coating is coated on the hydrophobically modified PET fabric, the coating thickness is uniform, the bottom is not exposed, there are no bubbles, and the surface is flat, and then it is volatilized at room temperature for 12 to 24 hours and then cured at 75 to 85° C. for 12 to 24 hours.

[0015] A second object of the present invention is to provide a waterproof and moisture resistant coating for flexible fabrics.

[0016] The third object of the present invention is to provide a waterproof and moisture-proof coating for use in flexible fabrics. Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a waterproof and moisture-proof coating for flexible fabrics, a preparation method and an application thereof. The present invention combines the hydrophobic modification of PET fabrics, the waterproof and moisture-proof coating and the super-hydrophobic coating to improve the waterproof and moisture-proof performance of the fabric and ensure its excellent mechanical properties. A hydrophobically modified micro-nano filler is introduced into the coating to additionally fill the fiber gaps, and a large number of micron / nano protrusions are uniformly attached to the fiber surface, which provides necessary roughness for the hydrophobicity of the fabric, increases the density of the coating, inhibits the fabric from absorbing and diffusing water vapor, and improves the waterproof and moisture-proof performance.

[0017] The nanoparticles provided by the present invention have a certain surface roughness, and can be added as fillers to block gaseous water from occupying internal pores, thereby playing a moisture-proof role. The hydrophobic properties of the nanoparticles are improved after the nanoparticles are hydrophobically modified, and the hydrophobic effect is better. Micron particles and hydrophobically modified nanoparticles are introduced and blended as composite fillers. According to the Wenzel-Cassie model theory, the film-forming material utilizes micro-nano structures and capillary forces to infiltrate the micro-nano fillers. The combination of micro-nano fillers can produce a double rough structure to form a hydrophobic surface, further blocking the penetration of gaseous molecules, extending the path of water vapor penetration, and improving the waterproof and moisture-proof properties of the coating.

[0018] The preparation method of the invention effectively solves the problem of waterproofing and moisture-proofing of PET fabric in a high-humidity environment, realizes the combination of hydrophobically modified PET fabric and waterproof and moisture-proof coating, has a simple preparation process, a wide range of applications, and broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 WCA (a), water absorption (b), moisture absorption (c) and mechanical properties (d) of silicone / PET coatings; Figure 2 WCA (a), water absorption (b) and moisture absorption (c) of modified nanofiller / silicone / PET coating; Figure 3 WCA (a), water absorption (b), moisture absorption (c), and mechanical properties (d) of micro-nano filler / silicone / PET composite coatings; Figure 4 WCA (a), water absorption (b), moisture absorption (c), and mechanical properties (d) of fabrics, fabric modifications, and micro-nano filler / organic silicon / PET composite coatings; Figure 5 A flow chart of the method for preparing a PET fabric having a hydrophobic and moisture-proof coating according to the present invention; Figure 6 It is the pure PET fabric used in the present invention. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to better understand and implement the technical solution of the present invention, the present invention is further described below in conjunction with specific embodiments and drawings, but the embodiments are not intended to limit the present invention.

[0021] The main purpose of the present invention is to improve the waterproof and moisture-proof performance of fabrics, and to provide a PET fabric waterproof and moisture-proof coating and a preparation method thereof. The coating prepared by the method is used to coat PET fabrics, has low production cost, and has excellent hydrophobic and moisture-proof performance and mechanical properties. The present invention realizes a combination of PET surface hydrophobic modification, waterproof and moisture-proof coating and super-hydrophobic coating, and provides a new research idea and approach for improving the waterproof and moisture-proof performance of PET fabrics.

[0022] In order to achieve the above object, the present invention provides a first aspect of a method for preparing a waterproof and moisture-proof coating for a flexible fabric, comprising the following steps: Preparation of modified nano-silica and mesoporous silica; The modified nano-silicon dioxide and mesoporous silicon dioxide are uniformly dispersed in an organic solvent, and then an organic silicon resin is added and mixed uniformly to obtain a composite coating; Hydrophobic modification of PET fabric; The composite coating is coated on the hydrophobically modified PET fabric, so that a waterproof and moisture-proof coating is prepared on the PET fabric.

[0023] In the composite coating, the mass ratio of the modified nano-silicon dioxide to the mesoporous silicon dioxide is 1:1-2; and the added amount of the organic silicone resin is 20-60 wt%.

[0024] The modified nano-silica includes methylated nano-silica or fluoromethylated nano-silica.

[0025] Specifically, the modified nano-silica is prepared by uniformly dispersing nano-silica in anhydrous ethanol, adding TMCS or TFTES, condensing and refluxing at 75-85° C. for 2-4 h, filtering, washing, drying and grinding to obtain methylated nano-silica or fluoromethylated nano-silica.

[0026] The mesoporous silica is prepared according to the following steps: Jeffamine D2000 surfactant was dissolved in anhydrous ethanol, and then water solvent was added and mixed to obtain a surfactant solution; uniformly dispersing TEOS in a surfactant solution to obtain a mixture; The mixture is aged for 20 to 24 hours, filtered and dried, and then calcined in air at 550 to 650° C. for 3 to 5 hours to obtain mesoporous silica.

[0027] The PET fabric is subjected to hydrophobic modification, including: immersing the PET fabric in a 0.5-1 mol / L NaOH solution for 2-4 hours, adding the fabric into anhydrous ethanol after washing and drying, and then adding TMCS or TFTES with stirring, condensing and refluxing at 75-85° C. for 2-4 hours, and then washing and drying to obtain the hydrophobically modified PET fabric.

[0028] After the composite coating is coated on the hydrophobically modified PET fabric, the coating thickness is uniform, the bottom is not exposed, there are no bubbles, and the surface is flat. Then it evaporates at room temperature for 12 to 24 hours and then cures at 75 to 85°C for 12 to 24 hours.

[0029] In one embodiment, a method for preparing a waterproof and moisture-proof coating for a flexible fabric is described in Figure 5 As shown, the process specifically includes the following steps: Step 1: modification of nano-silicon dioxide; Step 2: Synthesis of mesoporous silica; Step 3: preparing silicone resin; Step 4: Preparation of micro-nano filler / organic silicone resin composite coating; Step 5: hydrophobic modification of PET fabric; Step 6: Preparation of micro-nano filler / silicone / PET hydrophobic moisture-proof coating.

[0030] The specific steps of the nano-silicon dioxide modification are as follows: Add 2 g of nano-silica (NS) to 150 mL of anhydrous ethanol, add 0.2 g of TMCS or TFTES with stirring, and reflux at 80°C for 4 h. After filtration, washing, drying and grinding, methylated nano-silica (CH3-NS) or fluoromethylated nano-silica (CF3-NS) is obtained.

[0031] The specific steps of synthesizing the mesoporous silica are as follows: Take an appropriate amount of Jeffamine D2000 surfactant and dissolve it in a certain amount of anhydrous ethanol, then add deionized water under stirring. Add TEOS to the surfactant solution and stir vigorously at room temperature. The resulting mixture is aged in a heated water bath at a certain temperature for 20 hours and shaken. Then filter and dry. The surfactant is removed from the mixed solid by calcining at 600℃ in air for 4 hours to obtain mesoporous SiO2 (marked as MS), which is sealed and stored.

[0032] The specific steps of preparing the organosilicon resin are as follows: Weigh appropriate amounts of organic silicone emulsion (SH) and ethyl acetate in a certain ratio, stir for 30 min, ultrasonically disperse for 10 min, and stir for another 10 min to obtain a diluted organic silicone emulsion coating SH. n (The mass percentage of SH is n wt%), silicone resin solution, sealed and stored.

[0033] The specific steps of preparing the micro-nano filler / organic silicon composite coating are as follows: A certain amount of filler was weighed and added to ethyl acetate solvent, stirred for 10 min, ultrasonically dispersed for 15 min, and then a certain amount of SH was added, stirred for 20 min, ultrasonically dispersed for 30 min, and stirred for another 10 min to obtain a composite coating doped with micro-nano fillers, which was marked as filler x / SH. n (The mass percentage of micro-nano filler is x wt%), and sealed for storage. Experimental research found that coating with different solid contents (the best coating solid content is 40%) of silicone resin can give full play to the advantages of the coating.

[0034] Wherein, the micro-nano filler comprises modified nano-silica and mesoporous silica in a mass ratio of 1:1.

[0035] The specific steps of preparing the hydrophobic modification of PET fabric are as follows: The PET fabric was cut into small pieces of 300 mm × 200 mm, immersed in 1 mol / L NaOH solution for 4 h, washed and dried, and then the sample was added to 150 mL of anhydrous ethanol, stirred and added with 10 phr TMCS or TFTES, and condensed and refluxed at 80 ° C for 4 h. Then washed and dried to obtain methylated flexible material (CH3-PET) or fluoromethylated flexible material (CF3-PET). Figure 6 Shown is the actual picture of the PET fabric used.

[0036] The specific steps of the micro-nano filler / organic silicon / PET hydrophobic moisture-proof coating are as follows: The micro-nano filler / organic silicon composite coating was dropped onto the hydrophobically modified PET sample, and the coating was evenly applied using the 100 μm surface of the four-sided sample preparation device by scraping, and repeated three times to make the thickness uniform, without exposing the bottom, without bubbles, and with a smooth surface. After evaporation at room temperature for 12 h, the sample was cured in an oven at 80 ° C for 12 h to obtain a micro-nano filler / organic silicon / PET hydrophobic moisture-proof coating.

[0037] The present invention uses organic silicon water emulsion (SH), introduces micro / nano fillers (NS-CF3+MS) into SH, and adopts a knife coating method to coat the hydrophobic moisture-proof coating on the surface of the hydrophobic PET fabric. The combination of the hydrophobic modified fabric and the waterproof and moisture-proof coating makes PET have excellent hydrophobic, waterproof and moisture-proof properties.

[0038] The present invention increases the density of the coating by introducing hydrophobically modified micro-nano particles. Experimental studies have found that composite coatings combining different types of micro-nano fillers (the filler with the best performance is (NS-CF3+MS)) with silicone resin can reduce the water absorption rate of the material.

[0039] A second aspect of the present invention provides a waterproof and moisture-proof coating for a flexible fabric.

[0040] The third aspect of the present invention provides an application of a waterproof and moisture-proof coating in a flexible fabric. It should be noted that the experimental methods used in the present invention are all conventional methods unless otherwise specified; the reagents and materials used are all commercially available unless otherwise specified.

[0041] Example 1 Step 1, preparing silicone resin: Appropriate amounts of SH and ethyl acetate were weighed to make the SH solid content 45%, 40%, 35%, and 25%, stirred for 30 min, ultrasonically dispersed for 10 min, and stirred for another 10 min to obtain silicone water emulsion coatings SH with different solid contents. n (The mass percentage of SH is n wt%).

[0042] Step 2, preparation of PET samples: Cut the PET fabric into small pieces of 300mm×200mm, clean them with solvent, and dry the samples. Cut the dried samples into small pieces of equal size (25.4mm×76.2mm) according to the experimental requirements and save them for later use.

[0043] Step 3, preparation of silicone / PET hydrophobic moisture-proof coating: The silicone coating was dropped onto the PET sample and evenly coated with a 100 μm surface of a four-sided sampler by scraping. Repeat three times to make the thickness uniform, without exposing the bottom, without bubbles, and with a smooth surface. After evaporating at room temperature for 12 h, the sample was cured in an oven at 80 ° C for 12 h to obtain a silicone / PET hydrophobic and moisture-proof coating.

[0044] Example 2 A method for preparing a PET fabric with a hydrophobic and moisture-proof coating comprises the following steps: Step 1, modification of nano-silica: 2 g of NS was added to 150 mL of anhydrous ethanol, and 0.2 g of TMCS or TFTES was added under stirring, and the mixture was condensed and refluxed at 80°C for 4 h. Methylated nano-silica (CH3-NS) or fluoromethylated nano-silica (CF3-NS) was obtained by filtration, washing, drying and grinding.

[0045] Step 2, preparing silicone resin: Weigh appropriate amounts of SH and ethyl acetate in a ratio of 4:6, stir for 30 min, ultrasonically disperse for 10 min, and stir for another 10 min to obtain a diluted silicone water emulsion coating SH. 40 (The mass percentage of SH is 40 wt%) and stored in a sealed container.

[0046] Step 3, the specific steps of preparing the nanofiller / organic silicon composite coating are as follows: 1.5%, 1.0%, and 0.5% of filler were weighed and added to ethyl acetate solvent, stirred for 10 min, ultrasonically dispersed for 15 min, and then SH with a solid content of 40% was added, stirred for 20 min, ultrasonically dispersed for 30 min, and stirred for another 10 min to obtain composite coatings doped with different contents of nanofillers, marked as filler x / SH. 40 (The mass percentage of micro-nano filler is x wt%), sealed and stored.

[0047] Step 4, preparation of PET samples: Cut the PET fabric into small pieces of 300mm×200mm, clean them with solvent, and dry the samples. Cut the dried samples into small pieces of equal size (25.4mm×76.2mm) according to the experimental requirements and save them for later use.

[0048] Step 5, the specific steps of nanofiller / silicone / PET hydrophobic moisture-proof coating are as follows: The nanofiller / organic silicon composite coating was dropped onto the hydrophobically modified PET sample and evenly coated with a 100 μm surface of a four-sided sampler by scraping. Repeat three times to make the thickness uniform, without exposing the bottom, without bubbles, and with a smooth surface. After evaporating at room temperature for 12 h, the sample was cured in an oven at 80 ° C for 12 h to obtain a nanofiller / organic silicon / PET hydrophobic moisture-proof coating.

[0049] Example 3 Step 1, modification of nano-silica: 2 g of NS was added to 150 mL of anhydrous ethanol, and 0.2 g of TMCS or TFTES was added under stirring, and the mixture was condensed and refluxed at 80°C for 4 h. Methylated nano-silica (CH3-NS) or fluoromethylated nano-silica (CF3-NS) was obtained by filtration, washing, drying and grinding.

[0050] Step 2, synthesis of mesoporous silica: Take an appropriate amount of Jeffamine D2000 surfactant and dissolve it in a certain amount of anhydrous ethanol, then add deionized water under stirring. Add TEOS to the surfactant solution and stir vigorously at room temperature. The resulting mixture is aged in a heated water bath at 70°C for 20 hours and shaken. Then filter and dry. The surfactant is removed from the mixed solid by calcining at 600°C in air for 4 hours to obtain mesoporous SiO2 (marked as MS), which is sealed and stored.

[0051] Step 3, preparing silicone resin: Weigh appropriate amounts of SH and ethyl acetate in a ratio of 4:6, stir for 30 min, ultrasonically disperse for 10 min, and stir for another 10 min to obtain a diluted silicone water emulsion coating SH. 40 (The mass percentage of SH is 40wt%). Store in sealed container.

[0052] Step 4, preparing micro-nano filler / organic silicon composite coating: Weigh 1.0% of the filler and add it to the ethyl acetate solvent, stir for 10 min, and ultrasonically disperse for 15 min. Then add SH with a solid content of 40%, stir for 20 min, ultrasonically disperse for 30 min, and stir for another 10 min to obtain a composite coating doped with micro-nano fillers, which is marked as filler.1.0 / SH 40 , wherein the mass percentage of the micro-nano filler is 1.0 wt%, and the product is sealed and stored.

[0053] Step 5, preparation of PET samples: Cut the PET fabric into small pieces of 300mm×200mm, clean them with solvent, and dry the samples. Cut the dried samples into small pieces of equal size (25.4mm×76.2mm) according to the experimental requirements and save them for later use.

[0054] Step 6, Micro-nano filler / silicone / PET hydrophobic moisture-proof coating: The micro-nano filler / organic silicon composite coating was dropped onto the hydrophobically modified PET sample, and the coating was evenly applied using the 100 μm surface of the four-sided sample preparation device by scraping, and repeated three times to make the thickness uniform, without exposing the bottom, without bubbles, and with a smooth surface. After evaporation at room temperature for 12 h, the sample was cured in an oven at 80 ° C for 12 h to obtain a micro-nano filler / organic silicon / PET hydrophobic moisture-proof coating.

[0055] Example 4 Step 1, modification of nano-silica: 2 g of NS was added to 150 mL of anhydrous ethanol, and 0.2 g of TMCS or TFTES was added under stirring, and the mixture was condensed and refluxed at 80°C for 4 h. Methylated nano-silica (CH3-NS) or fluoromethylated nano-silica (CF3-NS) was obtained by filtration, washing, drying and grinding.

[0056] Step 2, synthesis of mesoporous silica: Take an appropriate amount of Jeffamine D2000 surfactant and dissolve it in a certain amount of anhydrous ethanol, then add deionized water under stirring. Add TEOS to the surfactant solution and stir vigorously at room temperature. Among them, the molar ratio of TEOS: D2000: H2O: ethanol = 1: 0.125: 220: 17, and the resulting mixture is aged in a heated water bath at 70°C for 20 hours and shaken. Then filter and dry. The surfactant is removed from the mixed solid by calcining at 600°C in air for 4 hours to obtain mesoporous SiO2 (marked as MS), which is sealed and stored.

[0057] Step 3, preparing silicone resin: SH and ethyl acetate were weighed in a ratio of 4:6, stirred for 30 min, ultrasonically dispersed for 10 min, and stirred for another 10 min to obtain a diluted organic silicone water emulsion coating SH. 40 (The mass percentage of SH is 40 wt%). Store in sealed container.

[0058] Step 4, preparing micro-nano filler / organic silicon composite coating: Weigh 1.0% filler and add it to ethyl acetate solvent, stir for 10 min, ultrasonically disperse for 15 min, then add 40% SH, stir for 20 min, ultrasonically disperse for 30 min, and stir for another 10 min to obtain a composite coating doped with micro-nano fillers, which is marked as filler. 1.0 / SH 40 (The mass percentage of the micro-nano filler is 1.0 wt%), and the mixture is sealed and stored. The filler comprises modified nano-silicon dioxide and mesoporous silicon dioxide in a mass ratio of 1:1.

[0059] Step 5, hydrophobic modification of PET: The PET fabric was cut into small pieces of 300 mm × 200 mm, immersed in 1 mol / L NaOH solution for 4 h, washed and dried, and then added to 150 mL of anhydrous ethanol, stirred and added with 10 phr TMCS or TFTES, and condensed and refluxed at 80 ° C for 4 h. Then washed and dried to obtain methylated flexible materials (CH3-PET) or fluoromethylated flexible materials (CF3-PET) Step 6, Micro-nano filler / silicone / PET hydrophobic moisture-proof coating: The micro-nano filler / organic silicon composite coating was dropped onto the hydrophobically modified PET sample, and the coating was evenly applied using the 100 μm surface of the four-sided sample preparation device by scraping, and repeated three times to make the thickness uniform, without exposing the bottom, without bubbles, and with a smooth surface. After evaporation at room temperature for 12 h, the sample was cured in an oven at 80 ° C for 12 h to obtain a micro-nano filler / organic silicon / PET hydrophobic moisture-proof coating.

[0060] In order to illustrate the relevant properties of the coating provided by the present invention, it is described in conjunction with the accompanying drawings.

[0061] Example 1 PET fabric was coated with an organic silicon coating, and WCA, water absorption, moisture absorption, and mechanical properties were tested. The results are shown in FIG1 .

[0062] exist Figure 1 In the WCA diagram of (a), the WCA of the PET fabric coated with the silicone resin (SH) coating increases with the decrease of the SH solid content and stabilizes within a certain range. In the water absorption and moisture absorption diagrams in Figure 1 (b) and (c), the water absorption is generally similar and much lower than that of the pure PET fabric; while the moisture absorption of the SH coating decreases first and then increases with the decrease of the solid content. The moisture absorption of the silicone coating with a solid content of 40 wt% is the lowest at 0.49%, and the moisture-proof performance is the best. Figure 1(d) The breaking strength and breaking elongation of each coating in the strength-elongation curve are better than those of pure PET fabric. Therefore, the SH coating with a solid content of 40% has a better waterproof and moisture-proof effect.

[0063] Example 2 PET fabric was modified with nanofiller / organic silicon coating, and WCA (a), water absorption (b), moisture absorption (c), and mechanical property tests (d) were performed, and the results are shown in Figure 2. When the content of nano-silicon dioxide (NS) increased from 0.5wt% to 1.5wt%, the waterproof and moisture-proof properties of the composite coating first increased and then decreased. After the nano-silicon dioxide was hydrophobically modified, the waterproof and moisture-proof properties of CF3-NS were better than those of CH3-NS, and the breaking strength and elongation were much higher than those of the unmodified particles. In general, the waterproof and moisture-proof properties of nano-silicon dioxide alone as a filler still cannot meet the product requirements, so it is necessary to mix micro-nano fillers to improve the above properties.

[0064] Figure 2 NS 0.5 / SH 40 Indicates a coating containing 0.5% nano-silicon dioxide and 40% organic silicon resin; NS 1.0 / SH 40 Indicates a coating containing 0.5% nano-silicon dioxide and 40% organic silicon resin; NS 1.5 / SH 40 It means a coating containing 1.5% nano-silicon dioxide and 40% organic silicon resin; (CH3-NS) 1.0 / SH 40 It means a coating containing 1.0% methylated nano-silica and 40% organic silicon resin; (CF3-NS) 1.0 / SH 40 It refers to a coating that is blended with 1.0% fluorinated nano-silica and 40% silicone resin.

[0065] Example 3 The results of waterproof, moisture-proof and mechanical properties are shown in Table 1 and Figure 3. As shown in Table 1, the thickness of the coating increases with the introduction of modified nano-silica and mesoporous silica. Compared with pure PET fabric, (MS+CF3-NS) 1.0 / SH 40 The coating thickness increased by 50μm, the breaking strength and elongation were significantly improved, and a smooth and dense coating was formed on the fabric surface. The composite coating WCA and water absorption rate were 137.3°, 1.56%, and 0.15%, respectively, with excellent waterproof and moisture-proof properties.

[0066] Figure 3 In the formula, Pure means a 40% silicone resin coating; NS 1.0 / SH40 It indicates a coating containing 1.0% nano-silicon dioxide and 40% organic silicon resin; MS 1.0 / SH 40 It indicates a coating containing 1.0% mesoporous silica and 40% organic silicone resin; MS+NS) 1.0 / SH 40 It means a coating with a total content of 1.0% nano-silica and mesoporous silica mixed with 40% silicone resin; (MS+CH3-NS) 1.0 / SH 40 It means a coating with a total content of 1.0% methylated nano-silica and mesoporous silica and a content of 40% organic silicone resin blended together; (MS+CF3-NS) 1.0 / SH 40 A coating comprising 1.0% fluorinated nano-silica and mesoporous silica mixed with 40% silicone resin.

[0067] Table 1 Thickness of micro-nano filler / organic silicon / PET composite coating

[0068] Using micro-nano filler / organic silicon composite coating, a large number of micron / nano-scale protrusions are evenly attached to the fiber surface, increasing the density of the coating and helping to improve its waterproof and moisture-proof properties.

[0069] Example 4 Waterproof, moisture-proof and mechanical properties Figure 4 It can be seen that the combination of hydrophobic modification of micro-nano fillers, waterproof and moisture-proof coating and hydrophobically modified PET fabric significantly improves the hydrophobic and moisture-proof properties and mechanical properties of the fabric, meeting the requirements of practical use.

[0070] Figure 4 In the formula, PET stands for polyethylene terephthalate; CH3-PET stands for methylated polyethylene terephthalate; (MS+CF3-NS) 1.0 / SH 40 / CH3-PET means a coating of 1.0% fluorinated nano-silica and mesoporous silica and 40% silicone resin blended on methyl-modified PET; CF3-PET means fluorinated polyethylene terephthalate; (MS+CF3-NS) 1.0 / SH 40 / CF3-PET indicates that a coating containing 1.0% fluorinated nano-silica and mesoporous silica and 40% silicone resin is coated on fluorine-modified PET.

[0071] In summary, the present invention discloses a method for preparing a waterproof and moisture-proof coating for flexible fabrics, and the preparation steps of the present invention include: hydrophobic modification of silicon dioxide nanoparticles; synthesis of mesoporous silica; preparation of silicone resin; preparation of micro-nano filler / silicone resin composite coating; hydrophobic modification of PET fabric; preparation of micro-nano filler / silicone / PET super-hydrophobic coating. On the one hand, hydrophobically modified micro-nano particles are introduced into the coating in this description, and fiber voids are additionally filled, and a large number of micron / nanoscale protrusions are uniformly attached to the fiber surface, providing the necessary roughness for the hydrophobicity of the fabric, increasing the compactness of the coating, and inhibiting the absorption and diffusion of water vapor by the fabric. On the other hand, the composite coating is combined with the hydrophobically modified PET fabric, which effectively solves the storage and use problems of PET fabric in high humidity environments, and has low cost and a wide range of application, and can be used for large-scale production of waterproof cloth, moisture-proof mats, etc.

[0072] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a waterproof and moisture-proof coating for flexible fabrics, characterized in that: The following steps are involved: Preparation of modified nano-silica and mesoporous silica; The modified nano-silicon dioxide and mesoporous silicon dioxide are uniformly dispersed in an organic solvent, and then an organic silicon resin is added and mixed uniformly to obtain a composite coating; Hydrophobic modification of PET fabric; The composite coating is coated on the hydrophobically modified PET fabric, so that a waterproof and moisture-proof coating is prepared on the PET fabric.

2. The method for preparing a waterproof and moisture-proof coating for flexible fabrics according to claim 1, characterized in that: In the composite coating, the mass ratio of the modified nano-silicon dioxide to the mesoporous silicon dioxide is 1:1-2; and the added amount of the organic silicone resin is 20-60 wt%.

3. The method for preparing a waterproof and moisture-proof coating for flexible fabrics according to claim 1, characterized in that: The modified nano-silica includes methylated nano-silica or fluoromethylated nano-silica.

4. The method for preparing a waterproof and moisture-proof coating for flexible fabrics according to claim 3, characterized in that: The nano-silica is uniformly dispersed in anhydrous ethanol, TMCS or TFTES is added, and the mixture is condensed and refluxed at 75-85° C. for 2-4 h. The methylated nano-silica or fluoromethylated nano-silica is obtained by suction filtration, washing, drying and grinding.

5. The method for preparing a waterproof and moisture-proof coating for flexible fabrics according to claim 1, characterized in that: The mesoporous silica is prepared according to the following steps: Jeffamine D2000 surfactant was dissolved in anhydrous ethanol, and then water solvent was added and mixed to obtain a surfactant solution; uniformly dispersing TEOS in a surfactant solution to obtain a mixture; The mixture is aged for 20 to 24 hours, filtered and dried, and then calcined in air at 550 to 650° C. for 3 to 5 hours to obtain mesoporous silica.

6. The method for preparing a waterproof and moisture-proof coating for flexible fabrics according to claim 1, characterized in that: The PET fabric is subjected to hydrophobic modification, including: immersing the PET fabric in a 0.5-1 mol / L NaOH solution for 2-4 hours, adding the fabric into anhydrous ethanol after washing and drying, and then adding TMCS or TFTES with stirring, condensing and refluxing at 75-85° C. for 2-4 hours, and then washing and drying to obtain the hydrophobically modified PET fabric.

7. The method for preparing a waterproof and moisture-proof coating for flexible fabrics according to claim 1, characterized in that: After the composite coating is coated on the hydrophobically modified PET fabric, the coating thickness is uniform, the bottom is not exposed, there are no bubbles, and the surface is flat. Then it evaporates at room temperature for 12 to 24 hours and then cures at 75 to 85°C for 12 to 24 hours.

8. A waterproof and moisture-proof coating for flexible fabrics prepared by the method according to any one of claims 1 to 7.

9. Use of the waterproof and moisture-proof coating according to claim 8 in flexible fabrics.

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