Sunscreen breathable knitted fabric and preparation method thereof

Abstract

The invention provides a sunscreen breathable knitted fabric and a preparation method thereof, and belongs to the technical field of sunscreen fabrics. Modified nano inorganic particles are added into the polyester stock solution and the spandex stock solution respectively, efficient and stable physical sunscreen performance is provided, the dispersion uniformity, binding strength, washing resistance and ultraviolet resistance of the inorganic particles are excellent, then the polyester filament yarn is further treated through the sunscreen modified solution, and the sunscreen performance of the polyester filament yarn is improved. The organic ultraviolet light absorber is fixed on the surface of the fiber, so that the sunscreen performance is improved. According to the invention, the water-soluble polyvinyl alcohol fiber is used as a pore-foaming agent, is stranded and twisted with the sunscreen polyester filament yarn, then is woven into the fabric, and finally is completely removed through a vacuum hot water dissolution process, so that a continuous and uniform three-dimensional microporous channel network can be formed in the fabric, and an efficient path is provided for circulation of moisture and air.

Description

Technical Field

[0001] This invention relates to the field of sun-protective fabric technology, and in particular to a sun-protective and breathable knitted fabric and its preparation method. Background Technology

[0002] With increased outdoor activities and heightened health awareness, the demand for clothing with sun protection functions is growing. Ideal sun-protective fabrics must meet three core requirements: first, a high UV protection factor (UPF) to effectively block UVA and UVB rays; second, good breathability and moisture management to ensure comfortable wear and prevent stuffiness; and third, washability and durability to ensure that the sun protection function does not rapidly diminish with daily washing.

[0003] Currently, sun-protective fabrics on the market mainly achieve their protection through the following methods: 1) Using a high-density weaving structure to reduce UV transmission through physical means, but this method often results in thick fabrics with poor breathability; 2) Performing finishing processes on fibers or fabrics to add UV absorbers or shielding agents, but this method is prone to functional degradation and insufficient durability due to washing and friction; 3) Using fibers with inherent UV protection (such as matte polyester), but their UPF value is limited and it is difficult to achieve the highest level of protection.

[0004] Therefore, the main problem to be solved is to prepare a knitted fabric that combines sun protection and breathability while maintaining the fabric's washability and durability. Summary of the Invention

[0005] In view of this, the present invention provides a method for preparing a sun-protective and breathable knitted fabric, comprising the following steps:

[0006] (1) Preparation of sunscreen modified polyester: The modified nano titanium dioxide and zinc oxide mixture is added to the polyester raw solution and spun; then the polyester filament obtained by spinning is placed in the sunscreen modified solution for modification treatment to obtain sunscreen modified polyester filament.

[0007] (2) The sun-protective modified polyester filament is used as the original yarn and is combined and twisted with water-soluble polyvinyl alcohol fiber to make a composite yarn.

[0008] (3) The composite yarn and modified spandex are knitted together using a plain weave structure to obtain a knitted fabric;

[0009] (4) Arrange the knitted blank in a vacuum tank, add water to immerse it, first evacuate to 61-71 kPa, then raise the water temperature to 81-86℃ and keep it warm for 30 minutes to promote the dissolution of water-soluble polyvinyl alcohol fibers; continue to evacuate to make the water boil and keep it warm for 10 minutes to completely dissolve the water-soluble polyvinyl alcohol fibers and form uniform microporous channels inside the fabric; give the fabric breathability.

[0010] (5) Take out the fabric and dry it at 40-50℃, then stretch it by 1.1-1.3 times to open the micropores that have shrunk due to drying and fix their shape, thereby precisely controlling the final air permeability and pore size of the fabric and balancing air permeability and sun protection performance.

[0011] Preferably, the preparation method of the modified nano-titanium dioxide and zinc oxide mixture in step (1) is as follows: nano-TiO2 and nano-ZnO are mixed at a mass ratio of 1-2:1-2 and dried in an oven at 100-110℃ for 2 hours to remove surface adsorbed water; then hexadecyltrimethoxysilane is dissolved in anhydrous ethanol, the dried nano-titanium dioxide and zinc oxide mixture is added, mechanically stirred at 45-60℃ for 1-2 hours, centrifuged, unreacted coupling agent is washed with ethanol, and dried at 50-60℃ for 2-4 hours to obtain the modified nano-titanium dioxide and zinc oxide mixture.

[0012] Preferably, the modified nano-titanium dioxide and zinc oxide mixture in step (1) is 3-5% of the mass of the polyester raw material.

[0013] Preferably, the sunscreen modified solution in step (1) comprises the following components in mass concentration: 3%-8% 2,4-dihydroxybenzophenone, 5%-10% silane coupling agent, 3%-5% catalyst, 3-8% solubilizer, and 50%-80% solvent.

[0014] More preferably, the silane coupling agent is silane coupling agent KH-570; the catalyst is 1-butyl-3-methylimidazolium tetrafluoroborate; the solubilizer is fatty alcohol polyoxyethylene ether; and the solvent is a mixture of water, ethanol and isopropanol in a volume ratio of 6-8:1-2:1-2.

[0015] Preferably, the ratio of the sunscreen modified solution to the polyester yarn in step (1) is 3-5:1.

[0016] Preferably, the mass ratio of water-soluble polyvinyl alcohol fiber to sunscreen modified polyester filament in step (2) is 15-25:75-85.

[0017] Preferably, the modified spandex in step (3) is prepared by adding 2-4% by mass of silane-modified nano-zinc oxide and 1-2% by mass of nano-silica to the spandex spinning solution, and then spinning to obtain modified spandex. This provides auxiliary sun protection and enhances the spandex's resistance to ultraviolet aging, while improving the fabric's strength and thermal stability without excessively affecting its elasticity.

[0018] Preferably, the preparation method of the silane-modified nano zinc oxide is as follows: hexadecyltrimethoxysilane is dissolved in anhydrous ethanol, dried nano zinc oxide is added, mechanically stirred at 50-60℃ for 1-2 hours, centrifuged, unreacted coupling agent is washed with ethanol, and dried at 50-60℃ for 2-4 hours to obtain silane-modified nano zinc oxide.

[0019] Preferably, the mass ratio of the modified spandex to the composite yarn in step (3) is 20-28:73-80.

[0020] The present invention also provides a sun-protective and breathable knitted fabric prepared by the above method.

[0021] Compared with existing technologies, this invention has the following beneficial effects: This invention provides a sun-protective and breathable knitted fabric and its preparation method. Modified nano-TiO2 / ZnO and silane-modified nano-ZnO are added to polyester and spandex dosses respectively, providing efficient and stable physical sun protection performance. Furthermore, silane coupling agents are used to surface-modify the inorganic nanoparticles, causing them to form chemical bonds or strong interactions with the polymer matrices of polyester and spandex, improving the dispersion uniformity and binding strength of the nanoparticles in the fibers, resulting in excellent wash resistance and UV resistance. Then, the polyester filaments are further treated with a sun-protective modification solution, causing organic UV absorbers to adhere to the fiber surface, further enhancing sun protection performance. This invention adds limited amounts of nano-zinc oxide and silicon dioxide to spandex, providing auxiliary sun protection while enhancing the spandex's own UV aging resistance, effectively preventing the strength and elasticity of elastic fibers from decreasing under long-term sun exposure, thereby maintaining the long-term stability of the fabric's overall sun protection performance and shape. This invention uses water-soluble polyvinyl alcohol fiber as a pore-forming agent. It is twisted together with sunscreen polyester filament and then woven into the fabric. Finally, it is completely removed by a vacuum hot water dissolution process, which can form a continuous and uniform three-dimensional microporous channel network inside the fabric, providing an efficient path for the circulation of moisture and air. Detailed Implementation

[0022] The present invention will be further described below with reference to the embodiments.

[0023] This invention provides a method for preparing a sun-protective and breathable knitted fabric, comprising the following steps:

[0024] (1) Preparation of sunscreen modified polyester: Add 3-5% of the mass of modified nano titanium dioxide and zinc oxide mixture to the polyester raw solution and spin it; then place the spun polyester filament in the sunscreen modified solution for modification treatment at a bath ratio of 3-5:1 to obtain sunscreen modified polyester filament.

[0025] (2) The sun-protective modified polyester filament is used as the original yarn and is combined and twisted with water-soluble polyvinyl alcohol fiber to make a composite yarn; the mass ratio of the water-soluble polyvinyl alcohol fiber to the sun-protective modified polyester filament is 15-25:75-85.

[0026] (3) Add 2-4% by mass of silane-modified nano zinc oxide and 1-2% by mass of nano silica to the spandex spinning solution, and then spin to obtain modified spandex; then use a warp plain weave structure to weave the composite yarn and the modified spandex to obtain a knitted fabric; the mass ratio of the modified spandex to the composite yarn is 20-28:73-80;

[0027] (4) Arrange the knitted blank in a vacuum tank, add water to immerse it, first evacuate to 61-71 kPa, then raise the water temperature to 81-86℃ and keep it warm for 30 minutes to promote the dissolution of water-soluble polyvinyl alcohol fibers; continue to evacuate to make the water boil and keep it warm for 10 minutes to completely dissolve the water-soluble polyvinyl alcohol fibers and form uniform microporous channels inside the fabric; give the fabric breathability.

[0028] (5) Take out the fabric and dry it at 40-50℃, then stretch it by 1.1-1.3 times to open the micropores that have shrunk due to drying and fix their shape, thereby precisely controlling the final air permeability and pore size of the fabric and balancing air permeability and sun protection performance.

[0029] The preparation method of the modified nano-titanium dioxide and zinc oxide mixture in step (1) is as follows: nano-TiO2 and nano-ZnO are mixed at a mass ratio of 1-2:1-2 and dried in an oven at 100-110℃ for 2 hours to remove surface adsorbed water; then 50-200mL of hexadecyltrimethoxysilane is dissolved in 300-500mL of anhydrous ethanol, and 10-15g of dried nano-titanium dioxide and zinc oxide mixture is added. The mixture is mechanically stirred at 45-60℃ for 1-2 hours, centrifuged, and the unreacted coupling agent hexadecyltrimethoxysilane is washed with ethanol. The mixture is then dried at 50-60℃ for 2-4 hours to obtain the modified nano-titanium dioxide and zinc oxide mixture.

[0030] The sunscreen modified solution in step (1) includes the following components in mass concentration: 3%-8% 2,4-dihydroxybenzophenone, 5%-10% silane coupling agent, 3%-5% catalyst, 3-8% solubilizer, and 50%-80% solvent.

[0031] In a specific embodiment of the present invention, the silane coupling agent is silane coupling agent KH-570; the catalyst is 1-butyl-3-methylimidazolium tetrafluoroborate; the solubilizer is fatty alcohol polyoxyethylene ether; and the solvent is a mixture of water, ethanol and isopropanol in a volume ratio of 7:2:1.

[0032] The preparation method of the silane-modified nano zinc oxide is as follows: dissolve 50-200 mL of hexadecyltrimethoxysilane in 300-500 mL of anhydrous ethanol, add 8-20 g of dried nano zinc oxide, mechanically stir at 50-60℃ for 1-2 hours, centrifuge, wash the unreacted coupling agent hexadecyltrimethoxysilane with ethanol, and dry at 50-60℃ for 2-4 hours to obtain silane-modified nano zinc oxide.

[0033] In a specific embodiment of the present invention, the particle size of the nano zinc oxide is 50-100 nm, the particle size of the nano titanium dioxide is 100-150 nm, and the particle size of the nano silicon dioxide is 20-50 nm; all raw materials used in the present invention are products that are commonly purchased from the market.

[0034] Example 1

[0035] The preparation method of the modified nano-titanium dioxide and zinc oxide mixture includes the following steps:

[0036] Nano-TiO2 and ZnO were mixed at a mass ratio of 1:1 and dried in an oven at 110℃ for 2 hours to remove surface adsorbed water. Then, 50 mL of hexadecyltrimethoxysilane was dissolved in 300 mL of anhydrous ethanol, and 12 g of the dried nano-titanium dioxide and zinc oxide mixture was added. The mixture was mechanically stirred at 55℃ for 2 hours, centrifuged, and the unreacted coupling agent hexadecyltrimethoxysilane was washed with ethanol. The mixture was then dried at 50℃ for 3 hours to obtain the modified nano-titanium dioxide and zinc oxide mixture.

[0037] Example 2

[0038] The preparation method of silane-modified nano zinc oxide includes the following steps:

[0039] Dissolve 50 mL of hexadecyltrimethoxysilane in 350 mL of anhydrous ethanol, add 12 g of dried nano zinc oxide, stir mechanically at 55 °C for 2 hours, centrifuge, wash the unreacted coupling agent hexadecyltrimethoxysilane with ethanol, and dry at 50 °C for 4 hours to obtain silane-modified nano zinc oxide.

[0040] Example 3

[0041] A method for preparing a sun-protective and breathable knitted fabric, comprising the following steps:

[0042] (1) Preparation of sunscreen modified polyester: 4% of the mass of the modified nano titanium dioxide and zinc oxide mixture (Example 1) was added to the polyester raw solution and spun; then the polyester filament obtained by spinning was placed in the sunscreen modification solution for modification treatment at a bath ratio of 4:1 to obtain sunscreen modified polyester filament; the sunscreen modification solution consists of the following components in mass concentration: 5% 2,4-dihydroxybenzophenone, 7% silane coupling agent, 4% catalyst, 5% solubilizer, and the remainder is solvent;

[0043] (2) The sun-protective modified polyester filament is used as the original yarn and is combined and twisted with water-soluble polyvinyl alcohol fiber to make a composite yarn; the mass ratio of the water-soluble polyvinyl alcohol fiber to the sun-protective modified polyester filament is 20:80.

[0044] (3) Add 3% by mass of silane-modified nano zinc oxide (Example 2) and 2% by mass of nano silica to the spandex spinning solution, and then spin to obtain modified spandex; then use a warp plain weave structure to weave the composite yarn and the modified spandex to obtain a knitted fabric; the mass ratio of the modified spandex to the composite yarn is 25:75;

[0045] (4) Arrange the knitted blank in a vacuum tank, add water to immerse it, first draw a vacuum of 70 kPa, then raise the water temperature to 85°C and keep it warm for 30 minutes to promote the dissolution of water-soluble polyvinyl alcohol fibers; continue to draw a vacuum to make the water boil and keep it warm for 10 minutes to make the water-soluble polyvinyl alcohol fibers completely dissolve and form uniform microporous channels inside the fabric; give the fabric breathability.

[0046] (5) Take out the fabric and dry it at 50°C. Then stretch it by 1.2 times in both length and width directions to open the micropores that have shrunk due to drying and fix their shape, thereby precisely controlling the final air permeability and pore size of the fabric and balancing air permeability and sun protection performance.

[0047] Example 4

[0048] A method for preparing a sun-protective and breathable knitted fabric, comprising the following steps:

[0049] (1) Preparation of sunscreen modified polyester: 5% of the mass of modified nano titanium dioxide and zinc oxide mixture was added to the polyester raw solution and spun; then the polyester filament obtained by spinning was placed in the sunscreen modification solution for modification treatment at a bath ratio of 4:1 to obtain sunscreen modified polyester filament; the sunscreen modification solution consists of the following components by mass concentration: 7% 2,4-dihydroxybenzophenone, 6% silane coupling agent, 4% catalyst, 4% solubilizer, and the remainder is solvent;

[0050] (2) The sun-protective modified polyester filament is used as the original yarn and is combined and twisted with water-soluble polyvinyl alcohol fiber to make a composite yarn; the mass ratio of the water-soluble polyvinyl alcohol fiber to the sun-protective modified polyester filament is 15:85.

[0051] (3) Add 4% by mass of silane-modified nano zinc oxide and 2% by mass of nano silica to the spandex spinning solution, and then spin to obtain modified spandex; then use a warp plain weave structure to weave the composite yarn and the modified spandex to obtain a knitted fabric; the mass ratio of the modified spandex to the composite yarn is 22:78.

[0052] (4) Arrange the knitted blank in a vacuum tank, add water to immerse it, first evacuate to 70 kPa, then raise the water temperature to 85°C and keep it warm for 30 minutes to promote the dissolution of water-soluble polyvinyl alcohol fibers; continue to evacuate to make the water boil and keep it warm for 10 minutes to make the water-soluble polyvinyl alcohol fibers completely dissolve and form uniform microporous channels inside the fabric; give the fabric breathability.

[0053] (5) Take out the fabric and dry it at 45°C. Then stretch it by 1.3 times in both length and width directions to open the micropores that have shrunk due to drying and fix their shape, thereby precisely controlling the final air permeability and pore size of the fabric and balancing air permeability and sun protection performance.

[0054] Comparative Example 1

[0055] A method for preparing a knitted fabric, with the same steps as in Example 3, except that in Comparative Example 1, a sun-protective modified polyester filament is used to replace the composite yarn.

[0056] Comparative Example 2

[0057] A method for preparing a knitted fabric, with the same steps as in Example 3, except that the mass ratio of water-soluble polyvinyl alcohol fiber to sunscreen modified polyester filament in Comparative Example 2 is 30:70.

[0058] Comparative Example 3

[0059] A method for preparing a knitted fabric, with the same steps as in Example 3, except that the method for preparing the sun-protective modified polyester in Comparative Example 3 is as follows: 4% by weight of a mixture of modified nano-titanium dioxide and zinc oxide (Example 1) is added to the polyester raw solution, and spinning is performed to obtain sun-protective modified polyester filament.

[0060] Comparative Example 4

[0061] A method for preparing a knitted fabric, with the same steps as in Example 3, except that the method for preparing the sun-protective modified polyester in Comparative Example 4 is as follows: polyester dope is used for spinning; then the polyester filaments obtained by spinning are placed in a sun-protective modification solution for modification treatment at a bath ratio of 4:1 to obtain sun-protective modified polyester filaments.

[0062] Comparative Example 5

[0063] A method for preparing a knitted fabric, with the same steps as in Example 3, except that no solubilizer is added to the sunscreen modification solution in Comparative Example 5.

[0064] Comparative Example 6

[0065] A method for preparing a knitted fabric, with the same steps as in Example 3, except that in Comparative Example 6, spandex is used to replace modified spandex.

[0066] UV protection performance test: UV protection was tested using a UV-2000F ultraviolet transmittance analyzer according to GB / T6505-2009 standard. Test method: A 5cm×5cm sample was cut from a flat section of the fabric at least 5cm from the selvage. The UV protection factor (UPF) was tested, and the sample position was adjusted so that each sample was tested 5-10 times and the average value was taken. The UV protection performance under immersion conditions was also tested to simulate the effect of human sweating on the fabric's UV resistance. The data results are shown in Table 1.

[0067] Air permeability test: The sample was conditioned under standard atmospheric pressure (20±2℃, relative humidity 62%~68%) for 24h. The test was conducted according to GB / T5453-1997 "Determination of air permeability of textile fabrics". The test was repeated 10 times and the average value was calculated. The data results are shown in Table 1.

[0068] Moisture permeability test: The moisture permeability was measured according to GB / T12704.1-2009 "Textiles - Test methods for moisture permeability of fabrics - Part 1: Moisture absorption method", and the data results are shown in Table 1.

[0069] Table 1

[0070] Normal state UPF UPF in humid state Air permeability (mm / s) <![CDATA[Water vapor transmission rate (g / m 2 ·24h)]]> Example 3 373 279 88 9945 Example 4 367 265 89 9978 Comparative Example 1 379 280 59 7218 Comparative Example 2 327 217 94 9997 Comparative Example 3 347 234 86 9934 Comparative Example 4 342 229 84 9927 Comparative Example 5 337 226 83 9924 Comparative Example 6 332 217 85 9964

[0071] After 200 simulated water washes, the UV protection performance was tested using the same method, and the results are shown in Table 2:

[0072] Table 2

[0073] UPF in normal condition after 200 washes UPF in wet state after 200 washes Example 3 365 260 Example 4 360 254 Comparative Example 1 362 268 Comparative Example 2 318 201 Comparative Example 3 332 228 Comparative Example 4 332 214 Comparative Example 5 317 206 Comparative Example 6 301 194

[0074] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a sun-protective and breathable knitted fabric, characterized in that, Includes the following steps: (1) Preparation of sunscreen modified polyester: The modified nano titanium dioxide and zinc oxide mixture is added to the polyester raw solution and spun; then the polyester filament obtained by spinning is placed in the sunscreen modified solution for modification treatment to obtain sunscreen modified polyester filament. (2) The sun-protective modified polyester filament is used as the original yarn and is combined and twisted with water-soluble polyvinyl alcohol fiber to make a composite yarn. (3) The composite yarn and modified spandex are knitted together using a plain weave structure to obtain a knitted fabric; (4) Arrange the knitted blank in a vacuum tank, add water to immerse it, first evacuate to 61-71 kPa, then raise the water temperature to 81-86℃ and keep it warm for 30 minutes; continue to evacuate to make the water boil and keep it warm for 10 minutes to form uniform microporous channels inside the fabric. (5) Take out the fabric and dry it at 40-50℃, and then stretch it by 1.1-1.3 times.

2. The method for preparing the sun-protective and breathable knitted fabric according to claim 1, characterized in that, The preparation method of the modified nano-titanium dioxide and zinc oxide mixture in step (1) is as follows: nano-TiO2 and nano-ZnO are mixed at a mass ratio of 1-2:1-2 and dried in an oven at 100-110℃ for 2 hours to remove surface adsorbed water; then hexadecyltrimethoxysilane is dissolved in anhydrous ethanol, the dried nano-titanium dioxide and zinc oxide mixture is added, and the mixture is mechanically stirred at 45-60℃ for 1-2 hours, centrifuged, and the unreacted coupling agent is washed with ethanol. The mixture is then dried at 50-60℃ for 2-4 hours to obtain the modified nano-titanium dioxide and zinc oxide mixture.

3. The method for preparing the sun-protective and breathable knitted fabric according to claim 1, characterized in that, The modified nano-titanium dioxide and zinc oxide mixture in step (1) is 3-5% of the mass of the polyester raw material.

4. The method for preparing the sun-protective and breathable knitted fabric according to claim 1, characterized in that, The sunscreen modified solution in step (1) comprises the following components by mass concentration: 3%-8% 2,4-dihydroxybenzophenone, 5%-10% silane coupling agent, 3%-5% catalyst, 3-8% solubilizer, and 50%-80% solvent; The silane coupling agent is silane coupling agent KH-570; the catalyst is 1-butyl-3-methylimidazolium tetrafluoroborate; the solubilizer is fatty alcohol polyoxyethylene ether; and the solvent is a mixture of water, ethanol, and isopropanol in a volume ratio of 6-8:1-2:1-2.

5. The method for preparing the sun-protective and breathable knitted fabric according to claim 1, characterized in that, The ratio of the sunscreen modified solution to the polyester yarn in step (1) is 3-5:

1.

6. The method for preparing the sun-protective and breathable knitted fabric according to claim 1, characterized in that, The mass ratio of the water-soluble polyvinyl alcohol fiber to the sunscreen modified polyester filament in step (2) is 15-25:75-85.

7. The method for preparing the sun-protective and breathable knitted fabric according to claim 1, characterized in that, The method for preparing the modified spandex in step (3) is as follows: add 2-4% by mass of silane-modified nano zinc oxide and 1-2% by mass of nano silica to the spandex spinning solution, and then spin to obtain the modified spandex.

8. The method for preparing the sun-protective and breathable knitted fabric according to claim 7, characterized in that, The preparation method of the silane-modified nano zinc oxide is as follows: hexadecyltrimethoxysilane is dissolved in anhydrous ethanol, dried nano zinc oxide is added, mechanically stirred at 50-60℃ for 1-2 hours, centrifuged, unreacted coupling agent is washed with ethanol, and dried at 50-60℃ for 2-4 hours to obtain silane-modified nano zinc oxide.

9. The method for preparing the sun-protective and breathable knitted fabric according to claim 1, characterized in that, The mass ratio of modified spandex to composite yarn in step (3) is 20-28:73-80.

10. A sun-protective and breathable knitted fabric, characterized in that, Prepared by the method according to any one of claims 1-9.