A method of fabric surface construction for durable water repellent coatings and products

Abstract

The application discloses a method for constructing a water-repellent durable coating on a fabric surface and a product, tests a static contact angle of water on the fabric before and after finishing, and finds that the hydrophobic effect of combed polyester is the best after being treated in THF solvent and under the condition that the silicon content is 60%, the contact angle can reach 167.3+ / -0.3 degrees, and the fabric has super-hydrophobicity, self-cleaning and oil absorption capacity. The anti-ultraviolet test is conducted on the fabric finished by the microsphere coating, and it is found that the finished fabric has good anti-ultraviolet property. The mechanical stability of the microsphere coating of the combed polyester is tested, and it is found that the contact angle of the microsphere coating is still kept above 150 degrees after 36 cycles of adhesive resistance and 9 cycles of water resistance tests, which indicates that the pretreatment of the fabric by polydopamine is helpful to the improvement of the mechanical stability of the finishing coating. The finished fabric has good stability to acid and alkali liquid drops (pH=3-12), can maintain the hydrophobicity after long-time acid and alkali immersion, and has good wearing performance.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of functional textiles, and relates to fabric surface modification, in particular to a method for constructing a water-repellent durable coating on a fabric surface and a product. BACKGROUND

[0002] Organic silicon polymers have a variety of excellent properties, such as excellent biocompatibility, transparency, thermal stability and low surface energy, and are therefore often used in coatings, adhesives and flexible materials; however, organic silicon materials have low polarity and low surface energy, and are often poorly compatible with substrates. Inspired by biological structures, minimizing the contact area between liquids and fabrics is a widely used strategy to enhance superhydrophobicity, and various superhydrophobic coatings have been successfully prepared on fabrics by constructing micro / nano rough structure coatings through a top-down method, and in-situ growth and chemical secondary modification of low surface energy surfaces. However, the durability of superhydrophobic coatings on fabric surfaces has always been a challenge [Bulut Y, Sülar V. Effects of process parameters on mechanical properties of coated fabrics [J]. SARIIŞIKM. International Journal of Clothing Science and Technology, 2011, 23(4): 205-221. Pal S, Mondal S, Pal P, et al. Fabrication of durable, fluorine-free superhydrophobic cotton fabric for efficient self-cleaning and heavy / light oil-water separation [J]. Colloid and Interface Science Communications, 2021, 44: 100469]. SUMMARY

[0003] The present application increases the bonding strength of the block polymer microstructure coating to the fabric fibers by combining the finishing material with the vapor-induced phase separation process, improves the finishing durability of the block polymer vapor-induced phase separation coating fabric, and the hydrophobic effect of the coating is better, with a water contact angle of 167.3 ± 0.3° and 161.2 ± 0.6° respectively, reaching superhydrophobicity.

[0004] The present application adopts the following technical solutions:

[0005] A method for constructing a water-repellent durable coating on a fabric surface, comprising the following steps: inducing phase separation of a pretreated fabric with a polymer solution in a steam environment to construct a water-repellent durable coating on the fabric surface.

[0006] In the polymer solution, the polymer is PS- b PDMS, the solvent includes THF (tetrahydrofuran), CS2; the concentration of the polymer solution is 20-80 mg / mL, preferably 30-60 mg / mL.

[0007] In the present application, the pretreatment agent used for pretreating the fabric includes dopamine, and a polydopamine is formed on the fabric surface through polymerization. Specifically, the fabric is immersed in a dopamine solution and subjected to oscillation treatment to obtain a pretreated fabric; preferably, the concentration of the dopamine solution is 1-10 g / L; preferably, the oscillation treatment is oscillation at 20-50℃ for 10-30 h.

[0008] In the present application, the steam includes water vapor and organic solvent vapor; preferably, the organic solvent includes a small-molecule alcohol such as ethanol; and preferably, the steam environment is a saturated steam environment.

[0009] In the present application, the pretreated fabric is placed in a steam environment, and a polymer solution is added to the fabric surface to construct a water-repellent durable coating. 2 Preferably, the ratio of the upper surface area of the fabric to the polymer solution is 4 cm 2 : (20-80) μL, and further, the ratio of the upper surface area of the fabric to the polymer solution is 4 cm 2 : (25-50) μL; as common knowledge, the upper surface of the fabric is the surface for receiving the polymer solution.

[0010] In the present application, the method for constructing a water-repellent durable coating on a fabric surface is carried out at room temperature.

[0011] The present application discloses a fabric with a water-repellent durable coating prepared according to the method for constructing a water-repellent durable coating on a fabric surface.

[0012] The present application discloses the use of the above-mentioned fabric with a water-repellent durable coating in the preparation of a functional fabric; preferably, in the preparation of a hydrophobic fabric, a UV-resistant fabric, an acid- and alkali-resistant fabric or a self-cleaning fabric.

[0013] The present application uses dopamine to pretreat a fabric to improve the water-repellent property of PS- bThe durability and structure of the PDMS coating, especially the coating can maintain super-hydrophobic state and has good UV resistance after 36 times of adhesive resistance test and 9 times of water resistance test. The influence of steam type (water and ethanol), block copolymer silicon content, solvent (THF and CS2) and fabric texture on the surface morphology and hydrophobicity of polyester. In the water vapor atmosphere, the hydrophobic effect of the finished polyester is general. When the solvent is CS2, only the taffeta surface can form a small amount of porous coating, and the rest forms a granular coating. When the solvent is THF, the polyester surface forms a block film. In comparison, the hydrophobic effect of the polyester is generally higher after coating in the ethanol steam atmosphere, with the highest being 167.3 ± 0.3°. When the solvent is CS2, the surface coating of the polyester is irregular and spherical in shape. When the solvent is THF, more spherical morphology is generated on the surface of the polyester. It is worth noting that in THF, when the silicon content is 60%, the microspheres in the coating generated on the surface of the combed polyester are embedded in the fibers, greatly improving the durability. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 SEM images of three kinds of polyester after polydopamine deposition: a taffeta, b combed polyester, c cotton-like polyester.

[0015] Figure 2 Block polymer PS- b SEM images of PDMS coated fabrics in ethanol atmosphere: (a1-a2, A1-A2) taffeta, (b1-b2, B1-B2) combed polyester, (c1-c2, C1-C2) cotton-like polyester.

[0016] Figure 3 Block polymer PS- b SEM and particle size distribution images of PDMS phase separation in ethanol steam atmosphere: (a1-a2) taffeta, (b1-b2) combed polyester, (c1-c2) cotton-like polyester; (a3) taffeta, (b3) combed polyester, (c3) cotton-like polyester; (a1, b1, c1) block copolymer silicon content 50%, (a1, b1, c1) block copolymer silicon content 60%.

[0017] Figure 4 PS- b SEM images of PDMS phase separation in ethanol steam atmosphere: (a1-a2) taffeta, (b1-b2) combed polyester, (c1-c2) cotton-like polyester; (a1, b1, c1) block copolymer silicon content 50%, (a1, b1, c1) block copolymer silicon content 60%.

[0018] Figure 5 FTIR spectra of the combed PET before and after treatment (a) and XPS spectra of the combed PET after treatment (b) full spectrum, (bl) C spectrum, (b2) O spectrum, (b3) Si spectrum; combed PET finished with block copolymer containing 60% silicon under ethanol vapor induced phase separation with THF as solvent.

[0019] Figure 6 EDS spectra (a) and element content distribution (b-e) of the combed PET after treatment by ethanol vapor induced phase separation.

[0020] Figure 7 Contact angle of water on the surface of different PET finished with block copolymer: (a) water vapor atmosphere, solvent THF; (b) water vapor atmosphere, solvent CS2; (c) ethanol vapor atmosphere, solvent THF; (d) ethanol vapor atmosphere, solvent CS2.

[0021] Figure 8 Combed PET finished with block copolymer containing 60% silicon under ethanol vapor atmosphere with THF as solvent: (a1) untreated PET is wetted in water solution; (a2) finished PET floats in water solution; (b) state of different droplets on the surface of finished fabric.

[0022] Figure 9 Combed PET finished with block copolymer containing 60% silicon under ethanol vapor induced phase separation with THF as solvent: (a1-a4) adsorption of carbon tetrachloride (heavy oil) on finished PET in water solution; (b1-b4) self-cleaning process of methylene blue powder on the surface of finished fabric.

[0023] Figure 10 Super depth of field three-dimensional image of combed PET: (a) untreated PET; (b) PET finished with block copolymer containing 60% silicon under ethanol vapor induced phase separation with THF as solvent.

[0024] Figure 11 (a) UV transmittance curve and (b) UPF, UVB and UVA values of untreated fabric PET, dopamine deposited fabric (PDA PET) and microsphere coated finished fabric (PDAPET Finished, ethanol vapor induced phase separation with THF as solvent, containing 60% silicon).

[0025] Figure 12 TGA and DTG curves of combed PET after finishing by ethanol vapor induced phase separation (THF as solvent, containing 60% silicon) in nitrogen atmosphere.

[0026] Figure 13Static contact angle histogram of combing polyester treated by ethanol vapor induced phase separation (THF as solvent, 60% silicon content) : (a) anti-adhesion, (b) water washing resistance.

[0027] Figure 14 Static contact angle histogram of combing polyester treated by ethanol vapor induced phase separation (THF as solvent, 60% silicon content) : (a) anti-adhesion, (b) water washing resistance.

[0028] Figure 15 Water bead stability of fabrics treated by different block polymers. DETAILED DESCRIPTION

[0029] In the steam induced phase separation process, the polydopamine pretreatment layer has great influence on the subsequent coating, including the influence of the pretreatment on the surface morphology of the coating, the surface hydrophobicity, and the surface roughness of the treated fabric, the pretreatment and the selection of raw materials are related to the mechanical properties of the coating, such as anti-adhesion, water washing resistance, acid and alkali resistance, and especially the influence on the durability of the surface coating of the fabric.

[0030] The experimental materials used in the present application are existing products, and the specific preparation operation and performance test are conventional techniques. Dopamine hydrochloride, Beijing Inokai; Tris (hydroxymethyl) aminomethane, Shengnuokang Biological; 1.2 g of Tris (hydroxymethyl) aminomethane is weighed and dissolved in water, and the solution is controlled to pH=8.5 by dropwise adding hydrochloric acid to prepare a 10 mM Tris-HCl buffer solution. 2 ; Combing polyester, 117 g / m 2 ; Cotton-like polyester, 123 g / m 2 .

[0031] The thermal performance of the fabric is analyzed by using a thermal gravimetric analyzer (Diamond 5700). The sample is cut into a fine state, about 5 mg is taken and placed in a crucible, and then placed in the instrument for testing. The test atmosphere is nitrogen, the temperature range is 30℃-700℃, and the heating rate is 10℃ / min.

[0032] The wetting performance of the finished fabric surface is characterized by using a full-automatic micro-droplet wetting tester (SDC-200S). The polyester fabric is fixed flat on a glass slide using double-sided tape, 5 μL of deionized water is used as the test droplet, and the average value is obtained by measuring at any three points on the sample.

[0033] The surface morphology and three-dimensional structure of the fabric are characterized by using an ultra-depth three-dimensional microscopic system (VHX-1000). In the system, the fast depth synthesis & 3D display function is used, the fabric is placed under the lens, the Z-axis motorized stage is used, and the 3D image can be quickly displayed by pressing the remote control button twice.

[0034] The UV transmittance of the polyester fabric before and after finishing was tested using a bluefield optical UV transmittance analyzer (model: UV-2000), UPF, UVA and UVB values were calculated, and the anti-ultraviolet performance was evaluated. Test conditions: single-layer fabric sample, 5 different positions of the same sample were tested, and the average value was taken as the final result.

[0035] The air permeability of the fabric was tested using a full-automatic air permeability tester (model: YG461G), and the test method was in accordance with GB / T5453-1997 "Textiles-Determination of air permeability of fabrics". The test pressure was 100 Pa, the test area was 20 cm², and the nozzle diameter was Φ 4. The final value was obtained by averaging the test results of 5 times.

[0036] The bending stiffness of the fabric was tested to represent the bending stiffness, and the test standard was GB / T18318.1-2009 "Textiles-Determination of bending properties". The bending stiffness of the polyester fabric before and after treatment was tested on an automatic fabric stiffness tester (model: YG(B)022D), and the test condition parameters were: temperature 25℃, humidity 65%, light source and horizontal angle 41.4°, fabric width 2.5 cm. The average value of the bending length was obtained by testing 4 times in the warp direction, and the bending stiffness (G) in the warp direction was calculated according to the following formula:

[0037] G=m×C 3 ×10 -3

[0038] Wherein, G is the bending stiffness per unit width (mN·cm), m represents the grammage per unit area of the fabric (g·m -2 ), C represents the average bending length of the fabric (cm).

[0039] In accordance with the standard of GB / T 3923.1-2013 "Textiles-Determination of tensile properties of fabrics", the change of tensile breaking of the polyester fabric before and after finishing was tested on a universal material testing machine (model: INSTRON 5967). The sensor range was 1000N, the tensile speed was 10 cm / min, the clamping length was 10 cm, the cloth width was 5 cm, and the warp direction was measured 3 times to take the average value.

[0040] The chemical stability of the block copolymer PS- b -PDMS microsphere coating finished fabric was characterized by immersing the polyester fabric sample in a solution with pH=3 or pH=13 for 24 h (acid was prepared from HCl, and base was prepared from NaOH), taking out and washing, drying, observing the SEM surface morphology and the change of WCA.

[0041] Washing resistance test: The finished polyester fabric was treated by a washing fastness instrument (Model: WASHTEC-P), wherein the washing liquid formula was as follows: bath ratio 1:30, neutral washing liquid concentration 2 g / L. The test conditions were as follows: temperature 40 °C, time 30 min, and deionized water cleaning for 1 min after washing.

[0042] Adhesive resistance test: 3M high-quality transparent adhesive tape was selected to test the adhesive resistance of the fabric. The finished polyester fabric was pasted on a glass slide, and the transparent adhesive tape was evenly pasted on the fabric. Then, the tape was slowly torn from left to right, and then torn from right to left in the same way. This process was regarded as one cycle, and the cycle number and the corresponding contact angle change were recorded.

[0043] Preparation Example

[0044] Under nitrogen protection, carbon disulfide (13.70 g, 0.18 mol), chloroform (53.75 g, 0.45 mol), acetone (26.15 g, 0.45 mol), tetrabutylammonium hydrogen sulfate (1.21 g, 3.55 mol) and 60.00 mL petroleum ether were mixed in a 1000 mL single-neck flask, stirred at 10 °C (three times of vacuum pumping), and 50% NaOH (50.40 g, 1.26 mol) was added dropwise, and the whole dropwise addition time was about 90 min. The reaction was stirred overnight, 450 mL water was added to dissolve the solid for cleaning, then the water layer was acidified with 60.00 mL concentrated HCL, stirred with N2 for 30 min, and the solid was thoroughly filtered and rinsed with water to obtain 12.88 g of dark yellow crude product. The crude product was dissolved in a mixture of toluene and acetone (volume ratio 4:1), vacuum filtered and dried to obtain 10.00 g of light yellow solid powder S, S' bis (α, α'-dimethyl-α''-acetic acid) trithiocarbonate.

[0045] Under nitrogen protection, 10.40 g of styrene (purified by vacuum distillation) and 282 mg of BDATC trithiocarbonate were added to a single-neck flask containing 5 mL of super-dry tetrahydrofuran, 16.42 mg of azobisisobutyronitrile (AIBN, recrystallized and purified) was added, the reaction device was placed in a pre-cooled low-temperature magnetic stirrer, and the single-neck flask on the low-temperature magnetic stirrer was vacuumed and filled with nitrogen for three times. The oil bath was heated to 70 °C, the reaction device was transferred to the oil bath and incubated at this temperature for 17 h. After the reaction was completed, the polymerization was immediately terminated by cooling, and then the reaction solution was precipitated in ice anhydrous methanol, filtered and vacuum dried for 6 h to obtain 6.89 g of yellow solid (PS-BDATC, Mn=3802), with a yield of 66%. According to the above method, the amount of styrene was replaced by 6.24 g, and the product PS-BDATC, Mn=2658 was obtained.

[0046] Under nitrogen protection, 2.0 g of carboxyl-terminated polystyrene (PS-BDATC, Mn=3802) and 20 mL of anhydrous toluene were placed in separate three-necked flasks, and 196.2 mg of [unspecified ingredient] was added with stirring. N, N Carbonyl diimidazole (CDI) was reacted at room temperature for 2 h, followed by the addition of 2.1 g of hydroxypropyl-terminated polydimethylsiloxane (Mn=2000) to the reaction system. The temperature was then raised to 70 °C and maintained for 6 h. After the reaction was completed, the byproduct imidazole was filtered off, toluene was removed by rotary evaporation under reduced pressure, and the product was dried under vacuum to obtain a pale yellow solid (block polymer PS-). b 3.2 g of PDMS was extracted, with a yield of 80%. The infrared absorption curve shows a value of 1732.8 cm⁻¹. -1 The characteristic peak at that location belongs to PS- b - The C=O double bond of the ester group in the PDMS copolymer, 1061.9 cm -1 The absorption peak at δ is attributed to the stretching vibration absorption peak of Si-O-Si; in the hydrogen NMR, δ=0.10~0.50 ppm is the chemical shift of hydrogen protons on the silanyl group, and a vibration peak appears at δ=4.28 ppm, which is attributed to the methylene hydrogen (-CH2-OOC-) generated by the reaction of hydroxypropyl and terminal carboxyl groups, thus confirming the successful esterification reaction and the formation of block copolymer.

[0047] This invention PS- b The PDMS copolymer and its preparation process are illustrated below.

[0048]

[0049]

[0050] In this invention, the polymer is PS- b -PDMS, with a number-average molecular weight of 1000 to 15000.

[0051] Following the above method, PS- at different proportions of PDMS were obtained. b - PDMS block copolymers, during esterification, have the same molar amounts of carboxyl and hydroxyl groups; silicon content is expressed as the percentage of PDMS block molecular weight (Mn=2000) in the total block molecular weight. PS- b -PDMS (50%) is a copolymer of PS-BDATC (Mn=3802) and single-ended hydroxypropyl polydimethylsiloxane PDMS (Mn=2000); PS- b -PDMS (60%) is a copolymer of PS-BDATC (Mn=2658) and single-ended hydroxypropyl polydimethylsiloxane PDMS (Mn=2000).

[0052] Example 1 Pretreatment of polyester fabric with polydopamine (PDA)

[0053] Dopamine hydrochloride 0.5 g was weighed into 100 mL of Tris-HCl buffer solution to prepare a solution with a concentration of 5 g / L. The polyester fabric was immersed in the dopamine solution after being pre-soaked with deionized water, and was placed in a shaking water bath at 40°C for 24 h. After the reaction was completed, the polyester fabric was taken out, and the surface was washed with deionized water until the washing residual liquid was colorless, to obtain the pretreated fabric.

[0054] The present application utilizes polydopamine (PDA) pretreatment with good hydrophilicity and adhesion, and PDA is deposited on the surface of the polyester fabric to introduce hydrophilic groups such as hydroxyl and amino groups on the surface of the fabric. The water contact angle of the three fabrics after PDA deposition decreases, and the fabric becomes more hydrophilic. In addition, a small amount of particles appears on the surface of the fabric after PDA deposition, which is caused by the oxidation and aggregation of dopamine self-polymerization, as shown in Figure 1 .

[0055] Example 2 Process of preparing a "roughened" coating by steam-induced phase separation

[0056] The above treated dopamine polyester fabric was coated in a 30 mL wide-mouth bottle with a sealed lid, and the process was as follows: a sponge holder was placed in the wide-mouth bottle, and an atmospheric solvent (water or anhydrous ethanol) was pre-added to the container, a rubber plug was used to maintain the sealing of the container, and the atmosphere was cultured in an oven at a temperature of 25°C for 4 hours to reach the saturated vapor pressure; then a clean cover glass (2.2 x 2.2 cm²) and fabric (2 x 2 cm²) were placed on the sponge holder in turn, ensuring that the substrate (cover glass) was 1 cm away from the liquid surface of the steam atmosphere solvent; the container was sealed and left for 30 min, and then 50 μL of polymer (PS-PDMS) solution (solvent: THF or CS2) was cast onto the fabric using a microsyringe; after the organic solvent in the polymer solution was completely evaporated, the fabric was taken out, and a coating with microstructure was formed on the surface of the fabric. b -PDMS) solution (solvent: THF or CS2) was cast onto the fabric using a microsyringe; after the organic solvent in the polymer solution was completely evaporated, the fabric was taken out, and a coating with microstructure was formed on the surface of the fabric.

[0057] Taffeta, combed polyester and cotton-like polyester were selected as the finishing objects, and by changing the silicon content of the block copolymer, the type of solvent and the type of fabric structure, a microstructure was formed on the surface of the fabric according to the steam-induced phase separation process, and the surface wetting properties were studied.

[0058] Example 3 Steam-induced phase separation with water

[0059] Polydopamine pretreated taffeta, combed polyester and cotton-like polyester were selected as the experimental objects, and two block copolymers with different silicon contents, PS-PDMS and PS-PDMS, were selected, and the surface wetting properties of the fabrics were studied. b-PDMS (50% and 60%) was used as a coating material. Block polymers were applied to the surface of polyester fabrics using a vapor-induced phase separation process. Changing the solvent type resulted in different morphologies in the treated fabric fibers (e.g., ...). Figure 2 As shown in the figure, the polymer concentration is 40 mg / mL.

[0060] In water vapor-induced phase separation, when the treatment agent (PS-) b When the solvent for PDMS is THF, it is obvious that the fabric surface has polymer accumulation and film coverage; when the solvent is changed to CS2, a porous film coating is generated on the surface of polyester taffeta, while combed polyester and cotton-like polyester begin to show granular polymer accumulation.

[0061] Under the aforementioned solvent, block copolymer, and substrate conditions, the block polymers in the finishing solution tend to coat the fibers with a membrane. Polydopamine-treated fabrics are highly hydrophilic; while rapidly adsorbing water molecules in a water vapor atmosphere, the rate at which water diffuses into the treatment agent solution also accelerates. This leads to the rapid precipitation and solidification of the block polymers in the treatment solution, resulting in membrane coating. In other words, it is difficult for block polymers to form an ordered porous membrane in a short time.

[0062] Example 4: Ethanol vapor-induced block copolymer PS- b -PDMS phase separation

[0063] In ethanol vapor-induced phase separation, two types of PS-containing silica with concentrations of 50% and 60% were used. b -PDMS block copolymers were used to treat three types of polyester pretreated with polydopamine, with a finishing agent concentration of 40 mg / mL.

[0064] Using treatment agent (PS-) b When the solvent for PDMS is THF, the resulting coating morphology on the fabric surface is as follows: Figure 3 When treated with a block copolymer containing 50% silicon, microspheres formed on the surface of polyester taffeta fabric, but in small quantities and unevenly distributed. Combed polyester fibers formed independent microsphere morphologies, while the microspheres on the cotton-like polyester surface mainly adhered to the inner surface between fibers. When the silicon content of the block copolymer was increased to 60%, the distribution of microspheres on the surface of polyester taffeta fibers became more uniform. Compared to fabrics without polydopamine pretreatment, the microspheres in this coating were no longer dispersed between fibers but were uniformly distributed along the fiber surface. It is noteworthy that the increased silicon content of the block copolymer exhibited stronger microphase separation characteristics, and the organosilicon segments possessed stronger molecular mobility, thus forming a dense and uniformly distributed microsphere coating on the fiber surface. Figure 3(b2) In this fabric, individual fibers are coated with numerous microspheres with a particle size of 3.69 ± 1.30 μm. The microspheres are bonded to the fiber surface via a membrane layer at their bottom. In contrast, the microspheres formed on the surface of the cotton-like polyester after treatment have a diameter of 4.51 ± 1.31 μm, and the microspheres are more concentrated on the inner surface of the fiber. Figure 3 c2).

[0065] The results show that the fabric surface is more hydrophilic after dopamine pretreatment. When the block polymer in the treatment liquid is coagulated by organic vapor phase induction, the diffusion of small organic molecules in the vapor into the treatment liquid is blocked. This is actually beneficial for the polymer solution to slowly complete the molecular chain segment phase separation, aggregation and concentration and grow into spheres under the vapor atmosphere.

[0066] When the solvent in the treatment solution is changed to CS2, the microstructure of the coating surface resulting from the vapor-induced phase separation of the two block polymers on the fabric surface is as follows: Figure 4 It can be seen that a uniformly distributed ideal microsphere coating cannot be formed on the surface of any of the three fabrics. When the block polymer has a silicon content of 50%, the coating even begins to sink.

[0067] The surface chemical composition of the treated fabrics was tested using ATR-FTIR, XPS, and EDS. Combed polyester treated with a block copolymer THF solution under an ethanol vapor atmosphere was selected for testing. The ATR-IR values ​​of the combed polyester before and after treatment are shown below. Figure 5 As shown in (a). Compared to untreated combed polyester, the treated fabric has a length of 1000–1100 cm. -1 A broad peak appears at 1713.4 cm⁻¹, which is attributed to the stretching vibration absorption peak of Si-O-Si in the surface microsphere coating. After dopamine deposition and polymer coating finishing, the fabric exhibits this peak. -1 The intensity of the C=O absorption peak at this position decreases. Since the block copolymer structure in the coating also contains ester groups, a weakened absorption peak is retained at this wavenumber position. This change indicates that the combed polyester surface, after being treated by steam-induced phase separation, is affected by PS- b - PDMS block copolymer microsphere coating. Furthermore, the infrared curve at 1259.2 cm⁻¹... -1 Location and 799.3 cm -1 The positional peaks are attributed to the absorption peaks of Si-(CH3)2 in the organosilicon segments of the block copolymer.

[0068] After processing, combed polyester showed five elements in its XPS full spectrum: C, O, Si, and trace amounts of N and S. The results are as follows: Figure 5(b) shown. The N 1s absorption peak is very weak, indicating that the PDA pretreatment layer on the fabric surface is very thin. Further analysis of the elements in different chemical environments by narrow spectrum found that there were C-Si (284.08 eV), C-C / C-H (284.80 eV), C-O (286.08 eV), C=O (287.43 eV) and C=C (282.34 eV) in the C 1s narrow spectrum. The O 1s narrow spectrum proved the existence of Si-O-Si (534.03 eV), C=O (532.73 eV) and C-O (531.68 eV), and the Si 2p narrow spectrum fitting appeared two peaks, which corresponded to Si-O-Si (102.18 eV) and Si-C (101.53 eV) respectively. This fully confirmed that the chemical composition of the finished fabric surface was consistent with the chemical structure of the block copolymer used.

[0069] As Figure 6 shown, EDS energy spectrum test was carried out on the finished combed polyester. It was found that the fabric surface contained five elements of C, O, N, Si and S, which was consistent with the XPS result. The percentage content of various elements was 71.05%, 13.96%, 9.74%, 3.57% and 1.64% respectively. Further observation from Figure 6 it can be seen that the EDS element mapping showed that the Si element on the fabric surface was uniformly distributed. In summary, the block copolymer PS- b -PDMS was successfully coated on the surface of the polydopamine pretreated polyester fabric by steam induced phase separation method, forming a microsphere structure coating.

[0070] Example Five Hydrophobic Performance Analysis of Steam Induced PS- b -PDMS Block Copolymer Phase Separation

[0071] The static water contact angle was used to characterize the hydrophobic performance of the finished fabric, Figure 7 and the static water contact angle of the finished fabric under different process conditions was given.

[0072] From Figure 7As observed in (a) and (b), during water vapor-induced phase separation, when the two silicon-containing block copolymers were dissolved in THF to treat the fabric, the treatment did not significantly improve the hydrophobicity of PDA-pretreated polyester taffeta and combed polyester because the resulting coating film did not exhibit a rough morphology. In contrast, the static water contact angle of the cotton-like polyester increased to 153.0 ± 1.1° after treatment. The main reason for this result is that a dense nanoscale rough particle coating was formed on the surface of the cotton-like polyester, and the fiber microstructure surface combined with low surface energy PDMS can trap air to jointly resist water wetting. When the solvent was changed to CS2, the hydrophobicity of the three polyesters treated with block polymers containing 50% silicon was improved to varying degrees, with water contact angles of 126.7 ± 2.0°, 148.3 ± 1.4°, and 149.7 ± 0.89° after treatment, respectively. The surface coating of taffeta and combed polyester after finishing is the same as that of THF solution treatment, which is an uneven porous membrane, resulting in a lower water contact angle after treatment. Similarly, cotton-like polyester has a slightly raised rough morphology on the coating surface, just like THF solution treatment, resulting in greater surface roughness and better hydrophobicity.

[0073] from Figure 7 As shown in (c) and (d), in ethanol vapor-induced phase separation, when polyester taffeta is treated with a block copolymer THF solution containing 60% silicon, uniformly distributed microspheres are generated on the fabric surface, improving hydrophobic properties. The measured water contact angle is 134.3 ± 1.3°. When combed polyester and cotton-like polyester are treated under the same conditions, the microspheres in the coating structure are more uniformly dispersed and have a more uniform size, resulting in better hydrophobic effects. The water contact angles are 167.3 ± 0.3° and 161.2 ± 0.6°, respectively, achieving superhydrophobicity. It is easy to see that microsphere coatings on fabrics provide better hydrophobic functionality than porous membrane coatings.

[0074] The changes in the water wettability of polyester fabrics before and after finishing were measured as follows: Figure 8 As shown in (a1, a2). Among them, the untreated polyester fabric was immediately wetted after contact with the Rhodamine B aqueous solution, while the combed polyester fabric treated with block copolymer remained floating on the surface of the aqueous solution and was not wetted by water. Figure 8 (b) It shows that the finished fabric has excellent resistance to water, acidic and alkaline aqueous solutions, tea and milk.

[0075] exist Figure 9 In (a1-a4), carbon tetrachloride is mixed with water and settles at the bottom as oil droplets. When combed polyester comes into contact with these oil droplets, the fabric rapidly and completely absorbs the carbon tetrachloride, but does not absorb water. This demonstrates that superhydrophobic polyester fabrics possess strong oil absorption and water repellency capabilities.

[0076] To test the anti-staining ability of the finished fabric, self-cleaning test was conducted on the finished polyester fabric Figure 9 b1-b4). The fabric was pasted on a glass slide; and placed in a petri dish with an angle of about 15°; methylene powder was piled on the surface of the fabric, and then washed with a large syringe; after the water droplets contacted the fabric surface, the methylene powder was dissolved and quickly slid off the fabric, leaving almost no methylene powder and blue marks on the fabric surface. This shows that the finished fabric has good anti-staining ability.

[0077] Example Six Roughness Analysis of Fabric Microsphere Coating

[0078] The roughness of the microsphere coating on the fabric surface was observed by super-depth three-dimensional microscope. Figure 10 (a) For the untreated combed polyester surface, it can be seen that the fiber surface fluctuation range is within 5.49 μm, while the combed polyester surface after finishing with polymer microsphere coating has a fluctuation range of 41.22 μm Figure 10 (b).

[0079] Example Seven Anti-Ultraviolet Performance of Fabric

[0080] According to the classification of the ultraviolet protection performance of textiles, when UPF≥50 and UVB transmittance value <2.5, the textile can be identified as excellent protection. In order to compare the anti-ultraviolet performance of the polyester fabric before and after finishing, the ultraviolet transmittance of untreated polyester, dopamine treated and block polymer finished polyester fabric was tested, and the results are shown in Figure 11 .

[0081] From Figure 11 (a) the curve chart, it can be seen that the ultraviolet transmittance of the combed polyester before treatment is very high, far from reaching the standard of anti-ultraviolet fabric; after dopamine pretreatment and further finishing with block polymer, the ultraviolet transmittance of the fabric is almost 0, showing excellent ultraviolet absorption ability. In addition, the UPF value of the untreated polyester fabric is only 29.23, the UPF values of the dopamine pretreated fabric and the coated finished fabric are increased to 88.3 and 76.5 respectively, while the UVA and UVB of the coated finished fabric are reduced to 1.62 % and 1.25 %.

[0082] Example Eight Thermal Stability Analysis of Fabric

[0083] The change of thermal stability of the fabric before and after treatment was tested by thermogravimetric analysis, and the results are shown in Figure 12The untreated polyester has a major mass loss between 370℃ and 480℃, and the residual mass rate of the fabric is almost 0 when heated to 700℃; while the coated fabric has a decomposition between 300℃ and 440℃ due to the polystyrene segments, but the final residual mass reaches nearly 14%. In summary, the fabric after the deposition of polydopamine and the surface microsphere coating of the block copolymer PS-PDMS has an initial thermal decomposition temperature of up to 300℃ or above, and the thermal performance of the fabric remains good. b

[0084] Example Nine Stability Test of Microsphere Coated Polyester Fabric

[0085] In order to investigate the effect of polydopamine pretreatment on the durability of subsequent microsphere coating, the finished fabric was subjected to water washing and adhesive resistance tests, and the results are shown in Figure 13 It is measured that the finished fabric can still maintain a water static contact angle of 152.4° after 36 times of adhesive tape peeling Figure 13 (a), which is significantly improved in mechanical durability compared with the fabric directly coated with microspheres without polydopamine pretreatment (the water contact angle of the fabric is less than 150° after 6 times of adhesive or 5 times of water washing).

[0086] From Figure 13 (b), it can be seen that the water washing resistance of the fabric after polydopamine pretreatment and then coating is also significantly improved. The finished fabric still maintains a water contact angle of 150.2° after 9 times of water washing. Therefore, the polydopamine pretreatment of the fabric before microsphere coating not only can endow the fabric with super-hydrophobic properties and anti-ultraviolet function, but also significantly improves the mechanical wear resistance and water washing resistance of the coating.

[0087] The finished fabric was subjected to water environment test. The combed polyester treated with 60% silicon-containing block polymer THF solution in ethanol vapor atmosphere was selected as the test object. The aqueous solution with pH=1-14 was selected as the test liquid, which was dropped onto the surface of the fabric to test the static contact angle, and the results are shown in Figure 14 (a).The test shows that the finished fabric exhibits good hydrophobicity in strong acid and strong base environments, and can maintain a water contact angle of 150°-160° in most pH environments, especially in strong acid aqueous solution with pH=1.

[0088] In order to further explore the long-term soaking stability of the finished fabric in strong acid and alkali solution Figure 14b,c), the finishing fabric was immersed in water solution with pH = 3 and pH = 13 for 24 h, respectively. It was found that although the outer layer of microspheres on the fabric surface was destroyed after immersion, the microspheres were corroded, the polymer fused and formed a film in the gap between the fibers, but the rough morphology was still retained, so it still showed water contact angle of 147.3° (pH = 3) and 147.7° (pH = 13), thus showing good coating stability under long-term immersion in acidic or alkaline solution.

[0089] Example Ten Physical property test of coating finishing polyester fabric by steam-induced phase separation method

[0090] The combing polyester finishing with 60% silicon-containing block copolymer under steam-induced phase separation with THF as solvent was selected as the sample, and the textile and clothing performance was tested, and compared with the untreated polyester and PDA pretreated polyester.

[0091] The breaking strength and elongation at break of the untreated polyester were measured to be 257.64 N and 18.29%, respectively. After dopamine deposition pretreatment and block copolymer coating finishing, the breaking strength of the fabric was increased to 294.42 N and 303.12 N, respectively, and the elongation at break was 18.75% and 19.85%, respectively. The results showed that after PDA pretreatment and microsphere coating finishing, the breaking strength of the fabric was significantly improved; the microsphere coating finishing also improved the elongation at break of the fabric.

[0092] The bending stiffness test results of the fabric are shown in Table 1. Among them, the stiffness of the fabric before and after finishing changes little, especially the finishing fabric still retains the inherent softness of the textile, solving the problem of softness decrease caused by the rough structure formed by the conventional polymer microspheres.

[0093] The air permeability test results of the untreated polyester, PDA pretreated polyester and microsphere coated polyester are listed in Table 1, wherein the air permeability of the untreated polyester is 257.04 mm / s, and the air permeability of the PDA pretreated and block copolymer microsphere coated fabric is 275.14 mm / s and 256.90 mm / s, respectively, indicating that the finishing process does not cause the air permeability of the fabric to decrease.

[0094] Table 1 Comparison of physical properties of untreated polyester and coating finished combing polyester

[0095]

[0096] Comparative Example

[0097] Under nitrogen protection and in a 10°C water bath, 20.19 g of dodecanethiol, 48.10 g of acetone, and 1.29 g of tetrabutylammonium bromide were added sequentially to a four-necked flask. While stirring, 8.40 g of 50% NaOH solution was added dropwise over a period of at least 20 minutes. After the addition was complete, the mixture was kept in the same position for 15 minutes. Then, a mixed solution of 7.61 g of CS2 and 10.09 g of acetone was slowly added dropwise to the flask over a period of at least 20 minutes, during which the solution color changed from orange-yellow to wine-red. Finally, 17.81 g of chloroform was added, followed by 40.00 g of 50% NaOH solution (added over a period of more than 30 minutes), and the mixture was stirred overnight. Next, 150 mL of distilled water was added to the four-necked flask, followed by 25 mL of concentrated hydrochloric acid for acidification. After stirring for 30 min, a large amount of nitrogen gas was introduced and stirred. Finally, the mixture was filtered, and the obtained solid was dissolved in 250 mL of isopropanol to remove insoluble matter. The filtrate was concentrated by rotary evaporation at 45 °C. Finally, the product was recrystallized with n-hexane and dried to obtain 20.60 g of the pale yellow small molecule chain transfer agent DDMAT.

[0098] Under nitrogen protection, 10.40 g of styrene (purified by vacuum distillation) and 0.47 g of DDMAT trithiocarbonate were added to a single-necked flask containing 5 mL of ultra-dry tetrahydrofuran. 27.37 mg of azobisisobutyronitrile (AIBN, purified by recrystallization) was added. The reaction apparatus was placed in a pre-cooled low-temperature magnetic stirrer. The single-necked flask on the stirrer was evacuated and then purged with nitrogen using a vacuum pump, repeated three times. The oil bath was heated to 70°C, and the reaction apparatus was transferred to the oil bath and maintained at this temperature for 17 h. After the reaction was complete, the polymerization was immediately terminated by cooling. The reaction solution was then precipitated in ice-cold anhydrous methanol, filtered, and vacuum dried for 6 h to obtain 6.23 g of a yellow solid (PS-DDMAT), with a yield of 60%.

[0099] Under nitrogen protection, 2.00 g of carboxyl-terminated polystyrene (PS-DDMAT, Mn=3428) and 20 mL of anhydrous toluene were placed in separate three-necked flasks, and 94.6 mg of [unspecified ingredient] was added while stirring. N, N Carbonyl diimidazole (CDI) was reacted at room temperature for 2 h, then 1.46 g of bihydroxypropyl-terminated polydimethylsiloxane (Mn=5000) was added to the reaction system, the temperature was raised to 70 °C, and the reaction was maintained at this temperature for 6 h. After the reaction was completed, the byproduct imidazole was filtered off, toluene was removed by rotary evaporation under reduced pressure, and the product was dried under vacuum to obtain 2.98 g of a yellow solid (block polymer PDMS-). b -PS), yield 86%.

[0100]

[0101]

[0102] Referring to the preparation example, carboxyl-terminated polystyrene (PS-BDATC, Mn=2658) reacts with monohydroxypropyl terminated polydimethylsiloxane (Mn=1000) to obtain PS- b -PDMS block polymer.

[0103] Referring to the above method, the steam-induced finishing of the combed polyester is carried out, and THF is used as the solvent under ethanol steam-induced phase separation, and the concentration of the polymer solution is 40 mg / mL. The block polymer PDMS- b -PS, block polymer PS- b The water contact angle of the fabric after finishing with the block polymer PDMS- Figure 15 The block polymer PS- b The hydrophobic stability of the fabric after finishing with the block polymer PDMS is good.

[0104] Summary:

[0105] The present application deposits polydopamine on the surface of polyester taffeta, combed polyester and cotton-like polyester after pretreatment, and the hydrophilicity of the fabric after pretreatment is obviously improved. Then, the fabric is coated and finished by steam-induced phase separation, and by changing the types of steam, solvents (THF and CS2) and the silicon content (50%, 60%) of the block copolymer of the treating agent, the morphology of the microstructure on the surface of the fabric is changed to realize hydrophobicity.

[0106] The phase separation (VIPS) is induced in a water vapor atmosphere to form a coating on the surface of three different fabrics, polyester taffeta, combed polyester and cotton-like polyester. Among them, THF is used as the solvent to prepare the PS- b -PDMS block polymer solution, a film layer is formed on the surface of the combed polyester and cotton-like polyester fabric; CS2 is used as the solvent to produce uneven porous coating on the surface of polyester taffeta, and dense nanoscale protrusions on the surface of cotton-like polyester and combed polyester. Among the three finished fabrics, the cotton-like polyester has the best hydrophobicity, and its static contact angle with water can reach 153.0°.

[0107] Microspheres were obtained on the surface of the fabric coated with block copolymer containing 60% of silane when THF was used as solvent and ethanol as vapor atmosphere. Uniformly dispersed microspheres were generated on the surface of the combed polyester, and the microspheres were attached to the membrane layer on the fiber surface. When the cotton-like polyester was treated, irregular microspheres were generated on the inside of the fiber; when CS2 was used as solvent, the microspheres obtained on the surface of the fabric coated with block copolymer of different silane contents were irregular in shape, and the microspheres were mostly aggregated at the intersection of the warp and weft directions. The static contact angle of the fabric before and after finishing was compared. The combed polyester coating had the best hydrophobic effect, and when it was finished in a THF solution of block copolymer containing 60% of silane, the surface contact angle could reach 167.3 ± 0.26°, and the coating had superhydrophobicity, self-cleaning and strong oil absorption capacity. The anti-ultraviolet test of the finished fabric showed that the UPF of the finished fabric was 76.5 (> 50), and the UVA and UVB values were 1.62% and 1.25%, respectively, indicating that the finished fabric had good anti-ultraviolet function.

[0108] The mechanical properties, washing resistance and acid and alkali resistance of the microsphere coating of the combed polyester were tested. The water contact angle of the microsphere coating remained above 150° after 36 cycles of adhesive tape peeling, and the water contact angle was 150.2 ± 0.4° after 9 washing tests, indicating that the fabric was pretreated with dopamine deposition and then coated, and the mechanical stability of the coating was significantly improved. This is because the dopamine pretreatment increases the binding strength between the coating and the fabric fiber. The finished fabric has good stability to acid and alkali (pH = 3-12), and the coating still maintains good hydrophobicity after long-term acid and alkali soaking. The fabric after coating still maintains good air permeability and softness, and has good comprehensive performance.

Claims

1. A method for constructing a water-repellent and durable coating on a fabric surface, comprising the following steps: inducing phase separation in a steam environment on a pretreated fabric containing a polymer solution to construct a water-repellent and durable coating on the fabric surface; wherein the polymer in the polymer solution is PS-b-PDMS and the solvent is THF; the pretreatment agent used for the pretreated fabric includes dopamine; the steam is ethanol vapor; the silicon content of PS-b-PDMS is 60%; PS-b-PDMS is a copolymer of PS-BDATC and single-terminated hydroxypropyl polydimethylsiloxane PDMS, wherein the Mn of PS-BDATC is 2658 and the Mn of PDMS is 2000.

2. The method for constructing a water-repellent and durable coating on a fabric surface according to claim 1, characterized in that, The concentration of the polymer solution is 20–80 mg / mL.

3. The method for constructing a water-repellent and durable coating on a fabric surface according to claim 1, characterized in that, The pretreated fabric is placed in a steam environment, and a polymer solution is added to the fabric surface to create a water-repellent and durable coating.

4. A fabric with a water-repellent and durable coating prepared by the method for constructing a water-repellent and durable coating on the fabric surface according to claim 1.

5. The application of the fabric with the water-repellent and durable coating of claim 4 in the preparation of functional fabrics.

6. The application according to claim 5, characterized in that, The functional fabrics include hydrophobic fabrics, UV-resistant fabrics, acid and alkali resistant fabrics, and self-cleaning fabrics.

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