Preparation method of fluorine-free waterproof fabric

Abstract

The application belongs to the technical field of waterproof fabric and relates to a preparation method of a fluorine-free waterproof fabric, which comprises the following steps: dissolving a high-molecular polymer and a fluorine-free oil waterproof additive in an organic solvent to prepare waterproof spinning liquid; and electrostatically spraying the waterproof spinning liquid to the surface of the fabric, drying to obtain waterproof finishing fabric. The application has low energy consumption, high utilization rate of waterproof finishing agent, and does not produce wastewater, achieving the purpose of energy saving and emission reduction and avoiding environmental pollution. The application does not need to add a crosslinking agent, and realizes good water washing resistance of the waterproof fabric.

Description

Technical Field

[0001] This invention belongs to the field of waterproof fabric technology, and in particular relates to a method for preparing a fluorine-free waterproof fabric. Background Technology

[0002] Waterproofing is a crucial property of fabrics, playing an irreplaceable role in outdoor gear, sportswear, and medical protective equipment. With the continuous advancement of modern technology, the demand for waterproof fabrics is constantly increasing, from high-performance mountaineering clothing, fishing apparel, and ski jackets to multifunctional sportswear, raincoats, and professional raincoats. This expansion of applications has directly driven the deepening of related research. Developing new waterproof fabrics that combine high quality, durability, and environmental friendliness is of great significance.

[0003] The principle behind waterproof textiles is to prevent water molecules from passing through the fabric, thus achieving a waterproof effect. This is usually achieved by improving the fabric's manufacturing process or treating it with finishing agents to make the fabric's porosity smaller than the diameter of water molecules. Currently, the main waterproofing processes for textiles include hydrophobic agent finishing, coating finishing, and tightly woven fabrics. Hydrophobic agent finishing can ensure good waterproof properties, but existing methods suffer from insufficient wash resistance, complex processes, and high energy consumption. Summary of the Invention

[0004] [Technical Issues] Hydrophobic finishing methods can ensure that the fabric has good water resistance, but existing hydrophobic finishing methods have problems such as insufficient water resistance, complicated process and high energy consumption.

[0005] [Technical Solution] The first objective of this invention is to provide a method for preparing a fluorine-free waterproof fabric, comprising the following steps: (1) Preparation of waterproof spinning solution: A waterproof spinning solution is prepared by dissolving a polymer and a fluorine-free waterproofing agent in an organic solvent; the mass ratio of the polymer to the fluorine-free waterproofing agent is 1:0.5~1:2. (2) Electrostatic spray waterproofing finishing: Waterproof spinning solution is electrostatically sprayed onto the fabric surface and dried to obtain a waterproof finished fabric.

[0006] In one embodiment of the present invention, in step (1), the polymer is selected from one or more of polyurethane, polyacrylonitrile, polystyrene, polyvinylidene fluoride, polycaprolactone, polylactic acid, and polymethyl methacrylate.

[0007] In one embodiment of the present invention, in step (1), the polymer is thermoplastic polyurethane (TPU).

[0008] In one embodiment of the present invention, in step (1), the organic solvent is selected from one or more of N,N-dimethylformamide DMF, dimethylacetamide, tetrahydrofuran, and ethanol; the amount of organic solvent used is to ensure that the concentration of the polymer in the waterproof spinning solution is 3 to 10 wt%.

[0009] In one embodiment of the present invention, step (1) of the preparation method of the fluorine-free oil waterproofing agent includes the following steps: Ethyl acetate was heated and stirred until transparent. Octadecyl methacrylate and vinyltriethoxysilane were added and stirred until completely dissolved. Azobisisobutyronitrile (AIBN) was added, nitrogen gas was introduced, the temperature was raised and stirred, and after cooling, antioxidant BHT was added and stirred. Impurities were filtered out to obtain a fluorine-free waterproofing agent. The raw materials are composed of the following components by mass: ethyl acetate 45%~55%, octadecyl methacrylate 30%~40%, vinyltriethoxysilane 10%~15%, azobisisobutyronitrile 0.5%~1%, and antioxidant BHT 0.1%.

[0010] In one embodiment of the present invention, in the preparation method of the fluorine-free waterproofing agent, the stirring temperature for heating and stirring ethyl acetate until transparent is 55~65°C.

[0011] In one embodiment of the present invention, in the preparation method of the fluorine-free waterproofing agent, the added azobisisobutyronitrile is azobisisobutyronitrile dissolved in a small amount of ethyl acetate.

[0012] In one embodiment of the present invention, in the preparation method of the fluorine-free waterproofing agent, the nitrogen gas is introduced for 10-25 minutes.

[0013] In one embodiment of the present invention, in the preparation method of the fluorine-free waterproofing agent, the heating and stirring are carried out by heating to 70~80°C and stirring at a constant temperature for 3~4 hours.

[0014] In one embodiment of the present invention, in the preparation method of the fluorine-free oil waterproofing agent, the cooling is performed to 15~30°C.

[0015] In one embodiment of the present invention, in the preparation method of the fluorine-free oil waterproofing agent, antioxidant BHT is added and stirred for 15-30 min.

[0016] In one embodiment of the present invention, in the preparation method of the fluorine-free oil waterproofing agent, impurities are filtered out using a 200-mesh filter cloth.

[0017] In one embodiment of the present invention, in step (1), the dissolution method is to seal and stir at 15~40℃ for 7~12h.

[0018] In one embodiment of the present invention, in step (2), the fabric is selected from one of the following: polyester-cotton blended fabric, cotton-linen blended fabric, silk-cotton blended fabric, and wool-polyester blended fabric.

[0019] In one embodiment of the present invention, in step (2), the electrostatic spraying speed is 15~35 μl / min; the receiving distance is 8~20 cm; the voltage is 10~30 kV; the receiving roller rotation speed is set to 200~500 rpm; and the electrostatic spraying time is 40~100 min.

[0020] In one embodiment of the present invention, in step (2), the electrostatic spraying step is to wrap the receiving roller with silicone paper, wrap the silicone paper with fabric, draw the waterproof spinning liquid with a syringe, install the syringe on the injection pump, connect the high voltage electrode to the nozzle, set the parameters and run.

[0021] In one embodiment of the present invention, the nozzle is a needle nozzle.

[0022] In one embodiment of the present invention, in step (2), the drying conditions are 90~120℃ for 1~3 min. During the drying process, the polymer acts as a crosslinking agent, making the waterproof components firmly adhere to the fabric surface.

[0023] A second objective of this invention is to provide a fluorine-free waterproof fabric prepared by the above-described method.

[0024] A third objective of this invention is to provide the application of the above-mentioned fluorine-free waterproof fabric in the field of textiles.

[0025] Beneficial effects: This invention eliminates the high-temperature drying and baking process in the preparation of waterproof textiles, significantly reducing energy consumption. Simultaneously, the use of electrostatic spraying technology greatly improves the utilization rate of the waterproofing agent, and eliminates wastewater generation, achieving energy conservation and emission reduction, and avoiding environmental pollution. The drying process allows the polymer to act as a crosslinking agent, enabling the waterproof fabric to achieve good wash resistance without the need for additional crosslinking agents. Attached Figure Description

[0026] Figure 1 These are the SEM test results for the fabric. Figure 1 'a' represents untreated fabric. Figure 1 b and c are the fluorine-free waterproof fabrics prepared in Example 5, dried at 100°C and 120°C respectively. Figure 1 d and e are the fluorine-free waterproof fabrics prepared in Example 3, dried at 100°C and 120°C respectively.

[0027] Figure 2 It is the contact angle of the fluorine-free waterproof fabric dried at 100°C as described in Example 5.

[0028] Figure 3 It is the contact angle of the fluorine-free waterproof fabric dried at 120°C as described in Example 5.

[0029] Figure 4 It is the contact angle of the fluorine-free waterproof fabric dried at 100°C as described in Example 3.

[0030] Figure 5 It is the contact angle of the fluorine-free waterproof fabric dried at 120-120℃ as described in Example 3.

[0031] Figure 6 It is the contact angle of the fluorine-free waterproof fabric dried at 100°C as described in Example 2.

[0032] Figure 7 It is the contact angle of the fluorine-free waterproof fabric dried at 120°C as described in Example 2. Detailed Implementation

[0033] The experimental materials used in the following examples and comparative examples are shown in Table 1.

[0034] Table 1

[0035] The preparation method of the fluorine-free oil-based waterproofing agent includes the following steps: (1) Add 50% ethyl acetate to the flask, heat to 60°C and stir until the solvent is clear.

[0036] (2) Add 35% octadecyl methacrylate and 14.5% vinyltriethoxysilane in sequence, and stir for 10 min until completely dissolved.

[0037] (3) Dissolve 0.4% of azobisisobutyronitrile (AIBN) in a small amount of ethyl acetate and add it to the flask. Then purge the air with nitrogen for 15 min.

[0038] (4) Heat to 75°C and stir for 3-4 hours. After the reaction is complete, cool to room temperature and add 0.1% antioxidant BHT and stir for 20 min.

[0039] (5) Filter with 200 mesh filter cloth to remove impurities and obtain fluorine-free waterproofing agent with a viscosity of 2000 ~ 14000 cP.

[0040] Example 1 A method for preparing a fluorine-free waterproof fabric includes the following steps: (1) Preparation of waterproof spinning solution: First, add 0.7 g of the above-mentioned fluorine-free oil waterproofing agent to 17.9 g of N,N-dimethylformamide, stir magnetically for 30 min at room temperature, then add 1.4 g of thermoplastic polyurethane elastomer TPU, seal with sealing film, and stir magnetically for 12 h to obtain waterproof spinning solution; (2) Electrostatic spray waterproof finishing: Take a suitable length of silicone paper and wrap it around the receiving roller as a conductive base. Then, take a suitable length of cotton / polyester 60 / 40 fabric and install it and wrap it with silicone paper. Select a nozzle type of stainless steel needle (22#). Install the syringe on the injection pump and set the injection speed to 25 μl / min. Then turn on the XC digital display speed controller, set the rotation speed of the receiving roller to 300 rpm and set the receiving distance to 14 cm. Finally, connect the high voltage electrode to the nozzle, turn on the high voltage power supply, and apply a high voltage of 20 kV. The electrostatic spraying time is 40 min. After the electrostatic spraying is completed, turn off the equipment, remove the spun fabric from the receiving roller, cut the fabric into two parts, put one part into a vacuum drying oven and dry at 120℃ for 3 minutes, and put the other part into a vacuum drying oven and dry at 100℃ for 3 minutes.

[0041] Example 2 The only difference from Example 1 is that in step (1), the amount of fluorine-free waterproofing agent is changed to 1.4 g and the amount of N,N-dimethylformamide is changed to 17.2 g.

[0042] Example 3 The only difference from Example 1 is that in step (1), the amount of fluorine-free waterproofing agent is changed to 2.1 g and the amount of N,N-dimethylformamide is changed to 16.5 g.

[0043] Example 4 The only difference from Example 2 is that in step (2), the electrostatic spraying time is adjusted to 70 min.

[0044] Example 5 The only difference from Example 3 is that in step (2), the electrostatic spraying time is adjusted to 70 min.

[0045] Comparative Example 1 Same as Example 3, except that the waterproofing agent is used differently, in which the fabric is soaked in the waterproofing agent and then dried.

[0046] Its waterproof / hydrophobic effect is comparable to that of Example 3, but the amount of waterproofing agent used is more than 40% higher than that of Example 3, and the fabric feels stiffer, with breathability reduced by 25% compared to Example 3. This is because the hydrophobicity of the fluorine-free waterproof fabric of this invention comes from two aspects: firstly, the waterproofing function of the organosilicon component of the waterproofing agent itself, and secondly, the micro-nano structure formed by the waterproofing agent on the fabric surface, which enhances the hydrophobicity. This technology reduces the amount of waterproofing agent used while having minimal impact on the breathability of the fabric.

[0047] Comparative Example 2 Same as Example 3, except that the waterproofing agent is applied by brushing it onto the fabric and then drying it.

[0048] Its waterproof / hydrophobic effect is comparable to that of Example 3, but the amount of waterproofing agent used is more than 35% more than that of Example 3, and the fabric feels stiffer. The breathability is reduced by more than 30% compared with Example 3.

[0049] Comparative Example 3 Same as Example 3, except that the waterproofing agent is replaced with an equal amount of organosilicon-based ZJ-WF20 oil-based fluorine-free waterproofing agent (Guangzhou Zhuangjie Chemical Technology Co., Ltd.).

[0050] Because the waterproofing agent has a low viscosity, it drips from the spinneret, resulting in poor electrostatic spraying and uneven distribution of the waterproofing agent on the fabric surface. This causes visible spots, affecting the appearance. Compared to Example 3, the amount of waterproofing agent used and the fabric breathability are similar, but the waterproofing effect is worse (contact angle is approximately 116°). This may be because the waterproofing agent did not form a micro / nano structure on the fabric surface.

[0051] Test example: After the fabric was attached to the sample stage with conductive adhesive, it was sprayed with gold and subjected to SEM testing. The surface structure of the fabric is as follows: Figure 1 As shown. Figure 1 A is an untreated cotton / polyester 60 / 40 fabric. Figure 1 b and c are the fluorine-free waterproof fabrics prepared in Example 5, dried at 100°C and 120°C respectively. Figure 1 d and e are the fluorine-free waterproof fabrics prepared in Example 3, dried at 100°C and 120°C respectively. (Compared to...) Figure 1 Compared to a, Figure 1 Fabrics b~d are coated with a waterproof coating. According to... Figure 1 As can be seen from b~d, after drying, the high molecular polymer acts as a cross-linking agent, and the effective waterproof component adheres firmly to the fabric surface. According to... Figure 1 From b and d, we can see that the spinning time is 70 min. Figure 1 The effective components coated on surface b are more than those obtained by spinning in 40 minutes. Figure 1 d is more uniform.

[0052] Contact angle tests were performed on the fabric water droplets. The contact angle results for the cotton / polyester 60 / 40 blended fabric are shown in Table 2 and... Figures 2-7 The contact angles of the fluorine-free waterproof fabric prepared in Example 5, dried at 100°C and 120°C respectively, were 133.1° and 130.9°. Figure 2 , 3 As shown. The contact angles of the fluorine-free waterproof fabric prepared in Example 3, dried at 100°C and 120°C, are 127.1° and 125.9°, respectively. Figure 4 ,5 As shown. The contact angles of the fluorine-free waterproof fabric prepared in Example 2, dried at 100°C and 120°C, are 121.5° and 112.4°, respectively. Figure 6 , 7 As shown.

[0053] Table 2

[0054] According to Table 2, the original fabric without waterproofing treatment could not be tested for contact angle due to its excessively fast wetting speed. After a spinning time of 70 min, a TPU concentration of 7%, and a TPU to waterproofing agent ratio of 1:1.5 on the cotton / polyester 60 / 40 blended fabric, the contact angles at 100℃ and 120℃ were 133.1° and 130.9°, respectively. However, when the spinning time was reduced from 70 min to 40 min, the waterproof coating on the fabric became correspondingly thinner. At this point, with a TPU concentration of 7% and a TPU to waterproofing agent ratio of 1:1, the contact angles at 100℃ and 120℃ were 121.5° and 112.4°, respectively; and with a TPU to waterproofing agent ratio of 1:1.5, the contact angles at 100℃ and 120℃ were 127.1° and 125.9°, respectively.

[0055] This shows that the fabric exhibits the best waterproof effect when the spinning time is 70 min, the TPU concentration is 7%, the ratio of TPU to waterproofing agent is 1:1.5, and the drying treatment is carried out at 100℃.

[0056] The embodiments provided above are not intended to limit the scope of the invention, nor are the described steps intended to limit the order of execution. Any obvious modifications made to the invention by those skilled in the art based on existing common knowledge also fall within the scope of protection defined by the claims.

Claims

1. A method for preparing a fluorine-free waterproof fabric, characterized in that, Including the following steps: (1) Preparation of waterproof spinning solution: A waterproof spinning solution is prepared by dissolving a polymer and a fluorine-free waterproofing agent in an organic solvent; the mass ratio of the polymer to the fluorine-free waterproofing agent is 1:0.5~1:

2. (2) Electrostatic spray waterproofing finishing: Waterproof spinning solution is electrostatically sprayed onto the fabric surface and dried to obtain a waterproof finished fabric.

2. The preparation method according to claim 1, characterized in that, In step (1), the polymer is selected from one or more of polyurethane, polyacrylonitrile, polystyrene, polyvinylidene fluoride, polycaprolactone, polylactic acid, and polymethyl methacrylate.

3. The preparation method according to claim 1, characterized in that, In step (1), the organic solvent is selected from one or more of N,N-dimethylformamide DMF, dimethylacetamide, tetrahydrofuran, and ethanol; the amount of organic solvent used is to ensure that the concentration of the polymer in the waterproof spinning solution is 3~10 wt%.

4. The preparation method according to claim 1, characterized in that, In step (1), the preparation method of the fluorine-free oil waterproofing agent includes the following steps: Ethyl acetate was heated and stirred until transparent. Octadecyl methacrylate and vinyltriethoxysilane were added and stirred until completely dissolved. Azobisisobutyronitrile (AIBN) was added, nitrogen gas was introduced, the temperature was raised and stirred, and after cooling, antioxidant BHT was added and stirred. Impurities were filtered out to obtain a fluorine-free waterproofing agent. The raw materials are composed of the following components by mass: ethyl acetate 45%~55%, octadecyl methacrylate 30%~40%, vinyltriethoxysilane 10%~15%, azobisisobutyronitrile 0.5%~1%, and antioxidant BHT 0.1%.

5. The preparation method according to claim 4, characterized in that, Ethyl acetate was heated and stirred until transparent at a stirring temperature of 55-65°C; the temperature was then increased to 70-80°C and stirred at a constant temperature for 3-4 hours. Add antioxidant BHT and stir for 15-30 minutes.

6. The preparation method according to claim 1, characterized in that, In step (2), the fabric is selected from one of the following: polyester-cotton blended fabric, cotton-linen blended fabric, silk-cotton blended fabric, and wool-polyester blended fabric.

7. The preparation method according to claim 1, characterized in that, In step (2), the electrostatic spraying speed is 15~35 μl / min; the receiving distance is 8~20 cm; the voltage is 10~30 kV; the receiving roller rotation speed is set to 200~500 rpm; and the electrostatic spraying time is 40~100 min.

8. The preparation method according to claim 1, characterized in that, In step (2), the drying conditions are: drying at 90~120℃ for 1~3 min.

9. The fluorine-free waterproof fabric prepared by any of the preparation methods described in claims 1 to 8.

10. The application of the fluorine-free waterproof fabric of claim 9 in the field of textiles.

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