Breathable cool sandwich composite fabric and production method thereof

Abstract

The present application relates to the technical field of composite cloth, in particular to a breathable cool sandwich composite cloth and a production method thereof; the composite cloth is composed of a surface layer, an intermediate layer and an inner layer; the surface layer is made of polypropylene fiber; the intermediate layer is made of modified polyurethane fiber; and the inner layer is made of polyester fiber and flax fiber mixed in a mass ratio of 7-8:2-3. The inner layer of the composite cloth is made of polyester fiber and flax fiber, which has good moisture absorption and can provide cool feeling and wearing comfort; the intermediate layer is made of modified polyurethane fiber, which improves the heat conduction performance and makes the heat dissipate quickly; and the surface layer is made of polypropylene fiber, which ensures the strength of the composite cloth. The overall breathable performance of the composite cloth is good, the cool feeling effect is strong, and the wearing comfort is high.

Description

Technical Field

[0001] This invention relates to the field of composite fabric technology, specifically to a breathable, cool-feeling sandwich composite fabric and its production method. Background Technology

[0002] With the continuous development of science and technology, textile fabrics that meet people's different needs are emerging in an endless stream to satisfy consumer demand. However, existing single-layer textile fabrics can no longer meet people's daily needs, so multi-layer composite fabrics have emerged.

[0003] Composite fabrics can be made by combining different materials, giving them multiple functions such as waterproofing, antibacterial properties, heat insulation, flame retardancy, antistatic properties, and radiation protection. However, due to their multi-layered structure, composite fabrics suffer from reduced breathability and thermal conductivity, failing to provide a cooling sensation in high-temperature environments and resulting in decreased wearing comfort. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a breathable, cooling sandwich composite fabric and its production method.

[0005] The technical solution of the present invention is: a breathable cooling sandwich composite fabric, wherein the composite fabric is composed of a surface layer, a middle layer and an inner layer in a mass ratio of 1:0.5~0.7:1.1~1.3, the surface layer is made of polypropylene fiber; the middle layer is made of modified polyurethane fiber; and the inner layer is made of polyester fiber and flax fiber mixed in a mass ratio of 7~8:2~3.

[0006] Note: The inner layer of the above composite fabric is made of polyester and linen fibers, which have good moisture absorption, provide a cooling sensation and are comfortable to wear. The middle layer is made of modified polyurethane fibers, which improves thermal conductivity and allows heat to dissipate quickly. The outer layer is made of polypropylene fibers, which ensures the strength of the composite fabric. The composite fabric has good overall breathability, a strong cooling effect and high wearing comfort.

[0007] Furthermore, the method for preparing the modified polyurethane fiber includes the following steps:

[0008] S1. Add nano-alumina and lauric acid to methanol and stir for 2-4 hours to obtain activated nano-alumina; the mass ratio of nano-alumina, lauric acid and methanol is 1:0.2-0.4:4-6.

[0009] S2. Add the activated nano-alumina to the acrylate, heat to 50~60℃ while stirring, and then keep warm to load the surface of the activated nano-alumina with acrylate for 30~40 minutes. After the heat preservation is completed, nano-alumina with acrylate loaded on the surface is obtained. The mass ratio of activated nano-alumina to acrylate is 1:5~8.

[0010] S3. Add polyurethane resin and nano-alumina with acrylate loaded on the surface to a solvent, stir for 10-15 min, add an initiator to the solvent, and react at 60-80℃ for 4-5 h to graft acrylate onto the polyurethane resin backbone. Then evaporate and remove the solvent to obtain modified polyurethane resin. The mass ratio of polyurethane resin, nano-alumina with acrylate loaded on the surface, initiator and solvent is 10-12:0.2-0.5:0.05-0.1:100-200.

[0011] S4. The modified polyurethane resin is melt-spun at a temperature of 200~220℃ and a winding speed of 1000~1200m / min. After melt spinning, modified polyurethane fibers are obtained.

[0012] Explanation: The above method activates nano-alumina, and the surface of the activated alumina can adsorb acrylate. Subsequently, the acrylate can undergo in-situ polymerization under the action of an initiator to generate polyacrylate. At the same time, the acrylate can react with polyurethane resin to graft polyacrylate onto the main chain of polyurethane resin, which improves the binding between nano-alumina and polyurethane resin, avoids the decrease in the strength of polyurethane resin, and nano-alumina improves the thermal conductivity and moisture absorption properties of modified polyurethane fibers.

[0013] Further, in step S2, the method for preparing the acrylate is as follows:

[0014] S2-1. Add p-tert-butylcatechol and acryloyl chloride to anhydrous ethanol to obtain a mixed solution; the mass ratio of p-tert-butylcatechol, acryloyl chloride, and anhydrous ethanol is 1:0.6~0.8:6~9.

[0015] S2-2. Cool the mixed solution until the temperature drops by 5-10°C, then add pyridine once. Stop cooling and stir the mixed solution until the temperature rises by 3-6°C. Let it stand for 15-20 minutes. The initial temperature of the mixed solution is 25-30°C, and the amount of pyridine added at one time is 0.2-0.5% of the initial mass of the mixed solution.

[0016] S3-2. Repeat step S2-2 until the temperature of the mixed solution drops to 0~5℃. After standing for 1~2 hours, distill the mixed solution to separate the acrylate.

[0017] Explanation: The above method involves an acylation reaction between tert-butylcatechol and acryloyl chloride. During the reaction, the temperature is gradually lowered to reduce the formation of byproducts. Furthermore, the temperature is allowed to rise after each addition of pyridine to ensure that the pyridine is stably dispersed in the mixed solution. This process ultimately produces an acrylate monomer containing tert-butylcatechol groups. Acrylates containing tert-butylcatechol groups have stronger coordination ability and can effectively bind to the active sites on activated alumina, thereby improving the binding affinity between activated alumina and acrylates.

[0018] Further, in step S2, 3-isocyanate propyltriethoxysilane is gradually added dropwise to the acrylate during the heating process, and the amount of 3-isocyanate propyltriethoxysilane added accounts for 2 to 5% of the mass of the acrylate.

[0019] Note: Adding 3-isocyanate propyltriethoxysilane can further enhance the adsorption capacity of activated alumina for acrylates, allowing the surface of activated alumina to fully adsorb acrylates.

[0020] Further, in step S3, the solvent is any one of toluene, xylene, or dimethylformamide, or a mixture of multiple solvents in any proportion.

[0021] Note: The above solvents have excellent solubility for polyurethane resins and can fully disperse alumina, allowing the alumina to be evenly distributed within the polyurethane resin.

[0022] Furthermore, in step S3, the initiator is ammonium persulfate or potassium persulfate.

[0023] Note: The above initiators can provide sufficient free radicals to initiate the polymerization reaction of acrylates.

[0024] Furthermore, in step S3, a citric acid solution with a mass concentration of 8-12% is added to the solvent every 50-60 minutes during the reaction to adjust the pH value of the solvent to 5-6.

[0025] Note: Adding citric acid solution ensures that the pH value in the solvent remains stable, allowing the reaction to proceed under optimal conditions and ensuring its full completion.

[0026] On the other hand, the present invention provides a method for preparing a breathable cooling sandwich composite fabric, which includes the following steps:

[0027] Step 1: Weave polypropylene fibers to obtain the outer layer, weave modified polyurethane fibers to obtain the middle layer, and blend polyester fibers and flax fibers in a certain mass ratio and weave them to obtain the inner layer.

[0028] Step 2: Immerse the inner layer in the finishing solution for 30-40 minutes at a temperature of 50-60°C. After immersion, dry at 40-50°C for 1-2 hours to obtain the pretreated inner layer.

[0029] Step 3: Apply polyurethane adhesive to both sides of the intermediate layer. The coating thickness of the polyurethane adhesive is 20~30μm. Then, place the inner layer and the outer layer on both sides of the intermediate layer respectively, and press them together using a hot press to obtain the composite fabric. The pressing temperature is 120~140℃ and the pressure is 0.3~0.5MPa.

[0030] Explanation: The above preparation method improves the thermal conductivity of the inner layer by finishing the inner layer, allowing the heat of the inner layer to dissipate outward through the middle layer. The thermal conductivity of the outer layer is lower than that of the middle layer, so that when the composite fabric is worn, the heat of the inner layer can be fully conducted outward, while less ambient heat is conducted into the inner layer, effectively improving the cooling effect of the composite fabric.

[0031] Furthermore, the finishing solution comprises, by mass parts: 3-6 parts polyvinyl alcohol, 0.5-2 parts sodium alginate, 1-5 parts polyethylene glycol, 10-15 parts menthol, 5-10 parts palmitic acid, and 60-80 parts deionized water.

[0032] Note: The above finishing solution has a good finishing effect and can be fully absorbed by the inner fibers, improving the thermal conductivity of the inner fibers.

[0033] The beneficial effects of this invention are:

[0034] (1) The inner layer of the composite fabric of the present invention is made of polyester fiber and flax fiber, which has good moisture absorption, can provide a cool feeling and is comfortable to wear. The middle layer is made of modified polyurethane fiber, which improves the thermal conductivity and allows heat to dissipate quickly. The outer layer is made of polypropylene fiber, which ensures the strength of the composite fabric. The composite fabric has good overall breathability, strong cooling effect and high wearing comfort.

[0035] (2) In this invention, the nano-alumina is activated, and the surface of the activated alumina can adsorb acrylate. Subsequently, the acrylate can undergo in-situ polymerization to generate polyacrylate. At the same time, polyacrylate is grafted onto the polyurethane main chain, which improves the binding between the nano-alumina and the polyurethane resin, avoids the decrease in the strength of the polyurethane resin, and the nano-alumina improves the thermal conductivity and moisture absorption properties of the modified polyurethane fiber.

[0036] (3) The preparation method of the present invention improves the thermal conductivity of the inner layer by finishing the inner layer, so that the heat of the inner layer can be dissipated to the outside through the middle layer, while the thermal conductivity of the outer layer is lower than that of the middle layer. This allows the heat of the inner layer to be fully conducted to the outside when the composite fabric is worn, while less ambient heat is conducted to the inner layer, effectively improving the cooling effect of the composite fabric. Detailed Implementation

[0037] To further illustrate the methods and effects of this invention, the technical solution of this invention will be clearly and completely described below in conjunction with experiments.

[0038] Example 1: A breathable, cooling sandwich composite fabric, wherein the composite fabric is composed of a surface layer, a middle layer and an inner layer in a mass ratio of 1:0.6:1.2, the surface layer is made of polypropylene fiber; the middle layer is made of modified polyurethane fiber; and the inner layer is made of polyester fiber and linen fiber mixed in a mass ratio of 7.5:2.5.

[0039] The method for preparing the modified polyurethane fiber includes the following steps:

[0040] S1. Add nano-alumina and lauric acid to methanol and stir for 3 hours to obtain activated nano-alumina; the mass ratio of nano-alumina, lauric acid and methanol is 1:0.3:5.

[0041] S2. The activated nano-alumina was added to the acrylate and heated to 55°C with stirring. During heating, 3-isocyanate propyltriethoxysilane was gradually added dropwise to the acrylate. The mixture was then kept at this temperature for 35 minutes to load the surface of the activated nano-alumina with acrylate. After the temperature was reached, nano-alumina with acrylate loaded on its surface was obtained. The mass ratio of activated nano-alumina to acrylate was 1:7, and the amount of 3-isocyanate propyltriethoxysilane added accounted for 4% of the mass of the acrylate.

[0042] S3. Polyurethane resin and nano-alumina with acrylate loaded on its surface were added to a solvent and stirred for 12 min. Then, an initiator was added to the solvent, and the reaction was carried out at 70 °C for 4.5 h to graft acrylate onto the polyurethane resin backbone. During the reaction, a 10% citric acid solution was added to the solvent every 55 min to adjust the pH value of the solvent to 5.5. The solvent was then evaporated to obtain the modified polyurethane resin. The mass ratio of polyurethane resin, nano-alumina with acrylate loaded on its surface, initiator and solvent was 11:0.4:0.08:150. The solvent was dimethylformamide and the initiator was ammonium persulfate.

[0043] S4. The modified polyurethane resin is melt-spun at a temperature of 210℃ and a winding speed of 1100m / min. After melt spinning, modified polyurethane fibers are obtained.

[0044] The preparation method of the above acrylate is as follows:

[0045] S2-1. Add p-tert-butylcatechol and acryloyl chloride to anhydrous ethanol to obtain a mixed solution; the mass ratio of p-tert-butylcatechol, acryloyl chloride, and anhydrous ethanol is 1:0.7:8.

[0046] S2-2. Cool the mixed solution until the temperature drops by 8°C, then add pyridine once. Stop cooling and stir the mixed solution until the temperature rises by 4°C, then let it stand for 18 minutes. The initial temperature of the mixed solution is 28°C, and the amount of pyridine added at one time is 0.3% of the initial mass of the mixed solution.

[0047] S3-2. Repeat step S2-2 until the temperature of the mixed solution drops to 4°C. After standing for 1.5 hours, distill the mixed solution to obtain acrylate after separation.

[0048] The preparation method of the above-mentioned composite fabric includes the following steps:

[0049] Step 1: Weave polypropylene fibers to obtain the outer layer, weave modified polyurethane fibers to obtain the middle layer, and blend polyester fibers and flax fibers in a certain mass ratio and weave them to obtain the inner layer.

[0050] Step 2: Immerse the inner layer in the finishing solution for 35 minutes. The bath ratio during immersion is 1:12 and the temperature of the finishing solution is 55°C. After immersion, dry at 45°C for 1.5 hours to obtain the pretreated inner layer.

[0051] Step 3: Apply polyurethane adhesive to both sides of the intermediate layer. The coating thickness of the polyurethane adhesive is 25μm. Then, place the inner layer and the outer layer on both sides of the intermediate layer respectively, and press them together using a hot press to obtain the composite fabric. The pressing temperature is 130℃ and the pressure is 0.4MPa.

[0052] The finishing solution consists of the following components by mass: 5 parts polyvinyl alcohol, 1 part sodium alginate, 3 parts polyethylene glycol, 13 parts menthol, 8 parts palmitic acid, and 70 parts deionized water.

[0053] Example 2: This example is basically the same as Example 1, except that the inner layer is made of polyester fiber and linen fiber mixed in a mass ratio of 7:2.

[0054] Example 3: This example is basically the same as Example 1, except that the inner layer is made of polyester fiber and linen fiber mixed in a mass ratio of 8:3.

[0055] Example 4: This example is basically the same as Example 1, except that the mass ratio of nano-alumina, lauric acid and methanol is 1:0.2:4.

[0056] Example 5: This example is basically the same as Example 1, except that the mass ratio of nano-alumina, lauric acid and methanol is 1:0.4:6.

[0057] Example 6: This example is basically the same as Example 1, except that the amount of 3-isocyanate propyltriethoxysilane added is 2% of the mass of acrylate.

[0058] Example 7: This example is basically the same as Example 1, except that the amount of 3-isocyanate propyltriethoxysilane added is 5% of the mass of acrylate.

[0059] Example 8: This example is basically the same as Example 1, except that the mass ratio of polyurethane, nano-alumina with acrylate loaded on the surface, initiator and solvent is 10:0.2:0.05:100.

[0060] Example 9: This example is basically the same as Example 1, except that the mass ratio of polyurethane, nano-alumina with acrylate loaded on the surface, initiator and solvent is 12:0.5:0.1:200.

[0061] Example 10: This example is basically the same as Example 1, except that an initiator is added to the solvent and the reaction is carried out at 60°C for 4.5 hours.

[0062] Example 11: This example is basically the same as Example 1, except that an initiator is added to the solvent and the reaction is carried out at 80°C for 4.5 hours.

[0063] Example 12: This example is basically the same as Example 1, except that the mixed solution is cooled down until the temperature of the mixed solution drops by 5°C, then pyridine is added to the mixed solution once, and then the cooling is stopped and the mixed solution is stirred until the temperature of the mixed solution rises by 3°C.

[0064] Example 13: This example is basically the same as Example 1, except that the mixed solution is cooled down until the temperature of the mixed solution drops by 10°C, then pyridine is added to the mixed solution once, and then the cooling is stopped and the mixed solution is stirred until the temperature of the mixed solution rises by 6°C.

[0065] Example 14: This example is basically the same as Example 1, except that the composition of the finishing solution by mass parts includes: 3 parts polyvinyl alcohol, 0.5 parts sodium alginate, 1 part polyethylene glycol, 10 parts menthol, 5 parts palmitic acid, and 60 parts deionized water.

[0066] Example 15: This example is basically the same as Example 1, except that the composition of the finishing solution by mass parts includes: 6 parts polyvinyl alcohol, 2 parts sodium alginate, 5 parts polyethylene glycol, 15 parts menthol, 10 parts palmitic acid, and 80 parts deionized water.

[0067] Comparative Example 1: Referring to Example 1, the intermediate layer was made of unmodified polyurethane fiber.

[0068] Comparative Example 2: Referring to Example 1, the nano-alumina was not activated or loaded with acrylate, but was directly added to the solvent.

[0069] Comparative Example 3: Referring to Example 1, the nano-alumina was not activated and acrylate was directly loaded.

[0070] Comparative Example 4: Using Example 1 as a reference, pyridine was added without waiting for the temperature of the mixed solution to rise.

[0071] Comparative Example 5: Referring to Example 1, commercially available acrylate monomers were used instead of the acrylates in this application.

[0072] Comparative Example 6: Referring to Example 1, the inner layer was not processed.

[0073] Experimental Example: To investigate the influence of parameters in each embodiment on the performance of the composite fabric, the cooling coefficient of the composite fabric in each embodiment was tested according to GB / T35263-2017. The specific investigation is as follows:

[0074] Experiment Example 1: Investigating the effect of the inner layer composition on the properties of composite fabrics

[0075] Using Examples 1, 2, and 3, as well as Comparative Example 1, as experimental comparisons, the performance of composite fabrics with different inner layer compositions is shown in Table 1 below:

[0076] Table 1. Performance of composite fabrics with different inner layer compositions

[0077]

[0078] As can be seen from the data in Table 1, compared with Examples 1, 2 and 3, the composite fabric of Example 1 has the highest cooling coefficient, indicating that the composite fabric of Example 1 has the best cooling effect. This may be because the inner layer component of Example 1 has the best thermal conductivity, so the inner layer component selected in Example 1 is the optimal one.

[0079] Compared with Comparative Example 1, the cooling coefficient of the composite fabric was significantly reduced after the middle layer was made of unmodified polyurethane fiber. This may be because the thermal conductivity of the composite fabric deteriorated after the unmodified polyurethane fiber was used.

[0080] Experiment Example 2: Investigating the effect of the ratio of nano-alumina, lauric acid, and methanol on the properties of composite fabric.

[0081] Using Examples 1, 4, and 5, and Comparative Examples 2 and 3 as experimental comparisons, the properties of the composite fabrics with different proportions of nano-alumina, lauric acid, and methanol are shown in Table 2 below:

[0082] Table 2. Properties of composite fabrics with different proportions of nano-alumina, lauric acid, and methanol.

[0083]

[0084] As shown in Table 2, compared with Examples 1, 4, and 5, the composite fabric of Example 1 has the highest cooling coefficient, indicating that the composite fabric of Example 1 has the best cooling effect. This may be because the activated nano-alumina has the most adsorption sites on its surface under the ratio of nano-alumina, lauric acid, and methanol in Example 1, which can fully adsorb acrylate and allow the nano-alumina to be fully dispersed in the polyurethane fiber. Therefore, the ratio of nano-alumina, lauric acid, and methanol selected in Example 1 is the optimal one.

[0085] Compared with Comparative Examples 2 and 3, the cooling coefficient of the composite fabric was significantly reduced after the nano-alumina was not activated and acrylate was loaded. However, the cooling coefficient of the composite fabric was increased after the nano-alumina was not activated and acrylate was loaded directly, but it was still lower than that of the composite fabric in Example 1. This may be because after the nano-alumina was activated, the surface of the nano-alumina could fully adsorb the acrylate, so that the nano-alumina could be fully dispersed in the polyurethane fiber.

[0086] Experiment Example 3: Investigating the effect of the amount of 3-isocyanate propyltriethoxysilane added on the properties of composite fabric.

[0087] Using Examples 1, 6, and 7 as experimental comparisons, the properties of the composite fabrics with different amounts of 3-isocyanate propyltriethoxysilane added are shown in Table 3 below:

[0088] Table 3. Properties of composite fabrics with different amounts of 3-isocyanate propyltriethoxysilane.

[0089]

[0090] As shown in Table 3, the cooling coefficient of the composite fabric gradually increases with the increase of the amount of 3-isocyanate propyltriethoxysilane added. The composite fabric in Example 1 has the highest cooling coefficient. As the amount of 3-isocyanate propyltriethoxysilane added continues to increase, the cooling coefficient of the composite fabric begins to show no significant change. This may be because the acrylate adsorbed on the surface of the activated nano-alumina reaches its maximum value. Therefore, the amount of 3-isocyanate propyltriethoxysilane added in Example 1 is optimal.

[0091] Experiment Example 4: Investigating the effects of polyurethane, acrylate-loaded nano-alumina, and the ratio of initiator to solvent on the properties of composite fabric.

[0092] Using Examples 1, 8, and 9 as comparative experiments, the properties of composite fabrics with different ratios of polyurethane, nano-alumina with acrylate surface loading, and initiator and solvent are shown in Table 4 below:

[0093] Table 4. Properties of composite fabrics made of polyurethane, nano-alumina with acrylate surface loading, and initiator and solvent in different ratios.

[0094]

[0095] As shown in Table 4, the composite fabric of Example 1 has the highest cooling coefficient, indicating that the composite fabric of Example 1 has the best cooling effect. This may be because the reaction between polyurethane and polyurethane is most complete under the following ratio of polyurethane, nano-alumina with acrylate loaded on the surface, initiator and solvent in Example 1. Therefore, the polyurethane, nano-alumina with acrylate loaded on the surface, initiator and solvent ratio selected in Example 1 is the optimal one.

[0096] Experiment Example 5: Investigating the effect of reaction temperature on the properties of composite fabrics

[0097] Using Examples 1, 10, and 11 as experimental comparisons, the properties of the composite fabric at different reaction temperatures are shown in Table 5 below:

[0098] Table 5. Properties of composite fabrics at different reaction temperatures

[0099]

[0100] As shown in Table 5, the composite fabric of Example 1 has the highest cooling coefficient, indicating that the composite fabric of Example 1 has the best cooling effect. This may be because the acrylate can fully polymerize and graft onto the polyurethane at the reaction temperature of Example 1. Therefore, the reaction temperature selected in Example 1 is optimal.

[0101] Experiment Example 6: Investigating the effect of acrylate preparation temperature on the properties of composite fabrics

[0102] Using Examples 1, 12, and 13, as well as Comparative Examples 4 and 5, as experimental comparisons, the properties of the composite fabrics at different acrylate preparation temperatures are shown in Table 6 below:

[0103] Table 6 Properties of composite fabrics prepared at different acrylate temperatures

[0104]

[0105] As shown in Table 6, compared with Examples 1, 12 and 13, the composite fabric of Example 1 has the highest cooling coefficient, indicating that the composite fabric of Example 1 has the best cooling effect. This may be because the acrylate containing tert-butylcatechol has a higher yield and fewer by-products at the acrylate preparation temperature of Example 1. Therefore, the acrylate preparation temperature selected in Example 1 is the optimal.

[0106] Compared with Comparative Example 4, after the addition of pyridine, the cooling coefficient of the composite fabric decreased significantly without waiting for the temperature of the mixed solution to rise. This may be because without waiting for the temperature to rise, pyridine failed to be stably dispersed in the mixed solution, affecting the yield of acrylate containing tert-butylcatechol groups.

[0107] Compared with Comparative Example 5, the cooling coefficient of the composite fabric decreased significantly after using commercially available acrylate monomers in Example 1. This may be because the acrylate without tert-butylcatechol groups has poor coordination ability with the activated nano-alumina and cannot fully combine with the activated nano-alumina.

[0108] Experiment Example 7: Investigating the effect of finishing solution composition on the properties of composite fabrics.

[0109] Using Examples 1, 14, 15 and Comparative Example 6 as experimental comparisons, the properties of composite fabrics with different finishing solution compositions are shown in Table 7 below:

[0110] Table 7. Properties of composite fabrics with different finishing solution compositions

[0111]

[0112] As shown in Table 7, compared with Examples 1, 14, and 15, the composite fabric of Example 1 has the highest cooling coefficient, indicating that the composite fabric of Example 1 has the best cooling effect. This may be because the inner fiber has the best absorption effect of the finishing liquid under the finishing liquid composition of Example 1. Therefore, the composition of the finishing liquid selected in Example 1 is optimal.

[0113] Compared with Comparative Example 6, Example 1 showed a decrease in the cooling coefficient of the composite fabric after the inner layer was not treated, indicating that cooling treatment can improve the cooling coefficient of the composite fabric.

Claims

1. A breathable, cooling sandwich composite fabric, characterized in that, The composite fabric is composed of a surface layer, a middle layer and an inner layer in a mass ratio of 1:0.5~0.7:1.1~1.

3. The surface layer is made of polypropylene fiber; the middle layer is made of modified polyurethane fiber; and the inner layer is made of polyester fiber and flax fiber mixed in a mass ratio of 7~8:2~3. The method for preparing the modified polyurethane fiber includes the following steps: S1. Add nano-alumina and lauric acid to methanol and stir for 2-4 hours to obtain activated nano-alumina; the mass ratio of nano-alumina, lauric acid and methanol is 1:0.2-0.4:4-6. S2. Add the activated nano-alumina to the acrylate, heat to 50~60℃ while stirring, and then keep warm to load the surface of the activated nano-alumina with acrylate for 30~40 minutes. After the heat preservation is completed, nano-alumina with acrylate loaded on the surface is obtained. The mass ratio of activated nano-alumina to acrylate is 1:5~8. S3. Add polyurethane resin and nano-alumina with acrylate loaded on the surface to a solvent, stir for 10-15 min, add an initiator to the solvent, and react at 60-80℃ for 4-5 h to graft acrylate onto the polyurethane resin backbone. Then evaporate and remove the solvent to obtain modified polyurethane resin. The mass ratio of polyurethane resin, nano-alumina with acrylate loaded on the surface, initiator and solvent is 10-12:0.2-0.5:0.05-0.1:100-200. S4. The modified polyurethane resin is melt-spun at a temperature of 200~220℃ and a winding speed of 1000~1200m / min. After melt spinning, the modified polyurethane fiber is obtained. The method for preparing the acrylate is as follows: S2-1. Add p-tert-butylcatechol and acryloyl chloride to anhydrous ethanol to obtain a mixed solution; the mass ratio of p-tert-butylcatechol, acryloyl chloride, and anhydrous ethanol is 1:0.6~0.8:6~9. S2-2. Cool the mixed solution until the temperature drops by 5-10°C, then add pyridine once. Stop cooling and stir the mixed solution until the temperature rises by 3-6°C. Let it stand for 15-20 minutes. The initial temperature of the mixed solution is 25-30°C, and the amount of pyridine added at one time is 0.2-0.5% of the initial mass of the mixed solution. S3-2. Repeat step S2-2 until the temperature of the mixed solution drops to 0~5℃. After standing for 1~2 hours, distill the mixed solution to obtain acrylate.

2. The breathable, cooling sandwich composite fabric according to claim 1, characterized in that, In step S2, 3-isocyanate propyltriethoxysilane is gradually added dropwise to the acrylate during the heating process, and the amount of 3-isocyanate propyltriethoxysilane added accounts for 2 to 5% of the mass of the acrylate.

3. The breathable cooling sandwich composite fabric according to claim 1, characterized in that, In step S3, the solvent is any one or a mixture of toluene, xylene, or dimethylformamide in any proportion.

4. The breathable cooling sandwich composite fabric according to claim 1, characterized in that, In step S3, the initiator is ammonium persulfate or potassium persulfate.

5. The breathable, cooling sandwich composite fabric according to claim 1, characterized in that, In step S3, a citric acid solution with a mass concentration of 8-12% is added to the solvent every 50-60 minutes during the reaction to adjust the pH value of the solvent to 5-6.

6. A method for preparing a breathable, cooling sandwich composite fabric, used to prepare the breathable, cooling sandwich composite fabric as described in any one of claims 1 to 5, characterized in that, Includes the following steps: Step 1: Weave polypropylene fibers to obtain the outer layer, weave modified polyurethane fibers to obtain the middle layer, and blend polyester fibers and flax fibers in a certain mass ratio and weave them to obtain the inner layer. Step 2: Immerse the inner layer in the finishing solution for 30-40 minutes at a temperature of 50-60°C. After immersion, dry at 40-50°C for 1-2 hours to obtain the pretreated inner layer. Step 3: Apply polyurethane adhesive to both sides of the intermediate layer. The coating thickness of the polyurethane adhesive is 20~30μm. Then, place the inner layer and the outer layer on both sides of the intermediate layer respectively, and press them together using a hot press to obtain the composite fabric. The pressing temperature is 120~140℃ and the pressure is 0.3~0.5MPa.

7. The method for preparing the breathable cooling sandwich composite fabric according to claim 6, characterized in that, The finishing solution comprises, by mass parts: 3-6 parts polyvinyl alcohol, 0.5-2 parts sodium alginate, 1-5 parts polyethylene glycol, 10-15 parts menthol, 5-10 parts palmitic acid, and 60-80 parts deionized water.

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