A method for durable ultraviolet protection finishing of silk / polylactic acid fiber interwoven fabric

Abstract

The invention discloses a method for durable ultraviolet protection finishing of silk / polylactic acid fiber interwoven fabrics. Baicalin is used as an ultraviolet absorber to finish the silk / polylactic acid fiber interwoven fabrics. After 15 times of washing, the ultraviolet protection factor UPF of the silk / polylactic acid fiber interwoven fabrics finished with baicalin is greater than 40, and the UVA ultraviolet transmittance is less than 5%, which meets the technical index requirements of ultraviolet protection products in GB / T 18830-2009 "Assessment of ultraviolet protection performance of textiles". The baicalin used in the invention is a plant extract, which is a safe and eco-friendly chemical; it is used for ultraviolet protection finishing of silk / polylactic acid fiber interwoven fabrics, and the finishing effect has the advantages of high efficiency, durability, and small discoloration; the finishing method has the advantages of short process flow, small strength damage to the fabric, and low energy and water consumption.

Description

Technical Field

[0001] The invention relates to the technical field of functional finishing of textiles, and in particular to a method for durable ultraviolet protection finishing of a silk / polylactic acid fiber interwoven fabric. Background Art

[0002] Polylactic acid fiber is a polyester synthetic fiber made by solution spinning or melt spinning with polylactic acid ester obtained from natural sugars such as grains (such as corn) and beets. Its production process is environmentally friendly and can be naturally degraded after a period of time after being discarded. The degradation products are carbon dioxide and water that do not pollute the environment. Polylactic acid fiber can meet people's pursuit of green, sustainable and environmental protection, so polylactic acid fiber is recognized as an excellent "green and environmentally friendly fiber" in the new century. Polylactic acid fiber has attracted great attention from the textile industry due to its good biodegradability and is widely used in the development of new textile products. Silk is a protein fiber invented by ancient Chinese people. It is a high-end textile fiber. It is known as the "Queen of Fibers" for its bright luster, gorgeous appearance, good wearing comfort, soft feel, and excellent drape. It is used as a fiber material for high-end clothing. Silk / polylactic acid fiber interwoven fabric is a new type of textile that conforms to the development trend of the times. It has the characteristics of strong moisture absorption and moisture conduction, good breathability, comfortable wearing, good luster, and bright colors of dyed products. It is a new type of silk interwoven product.

[0003] Polylactic acid fiber does not contain aromatic rings, so the ultraviolet absorption rate is low and the transmittance is high, which makes it have good anti-ultraviolet aging performance. However, the problem is that the ultraviolet light transmittance of its white and light-colored thin textiles is high, which is harmful to human health and difficult to meet the requirements of textile raw materials for ultraviolet protection functional textiles. The ultraviolet protection factor (UPF) of pure polylactic acid fiber fabrics is low. Silk fiber contains aromatic amino acids such as tyrosine, tryptophan, phenylalanine, and histidine, which have a certain absorption capacity for ultraviolet rays. However, tyrosine, histidine, tryptophan, etc. can easily cause silk fibers to turn yellow. The yellowing of silk fabrics during wearing is a major problem, and dyed fabrics are easy to fade after long-term use. In addition, since most silk fabrics are relatively thin, the ultraviolet protection factor is low and the ultraviolet protection performance is poor. Obviously, the silk / polylactic acid fiber interwoven fabric composed of two ultraviolet protection properties also has poor ultraviolet protection performance. Therefore, it is necessary to carry out ultraviolet protection finishing on silk / polylactic acid fiber interwoven fabrics, especially for the thin silk / polylactic acid fiber interwoven fabrics worn in summer.

[0004] Common UV protection finishing is to treat textiles with synthetic UV absorbers. Silk and wool protein fiber textiles are often finished with water-soluble UV absorbers containing sulfonic acid groups, and the UV absorbers are adsorbed on the protein fibers by ionic bonding with the fibers. Polyester fiber textiles such as polyester and polylactic acid are often finished with non-water-soluble UV absorbers, and the UV absorbers are adsorbed on the polyester fibers by ionic bonding with the fibers. For silk / polylactic acid fiber interwoven fabrics, water-soluble UV absorbers and non-water-soluble UV absorbers should be used to finish the silk and polylactic acid fiber components respectively, so as to give them UV protection properties. If this technical solution is adopted, the UV protection finishing of silk / polylactic acid fiber interwoven fabrics can refer to its acid dye / disperse dye one-bath one-step dyeing method and two-bath two-step dyeing method, and use water-soluble UV absorbers and non-water-soluble UV absorbers for one-bath one-step method and two-bath two-step method. The disadvantages of this technical solution are: two types of UV absorbers are needed to finish the silk and polylactic acid fiber components respectively, and the cost of UV absorbers is high; the two-bath two-step finishing method is used, the process flow is long, which can easily lead to reduced fabric strength and high energy and water consumption.

[0005] According to GB / T 18830-2009 "Evaluation of UV Protection of Textiles": When the UPF of a textile is greater than 40 and the UVA transmittance is less than 5%, it can be called an "UV protection product"; when 40<UPF≤50, the label on the UV protection product is marked as UPF 40+; when UPF>50, it is marked as UPF 50+. For silk fabrics, polylactic acid fiber fabrics, and silk / polylactic acid fiber interwoven fabrics, it is a technical challenge to make the fabrics finished with UV absorbers meet the two requirements of UPF>40 and UVA transmittance <5% at the same time. Summary of the invention

[0006] The purpose of the present invention is to provide a method for durable ultraviolet protection finishing of silk / polylactic acid fiber interwoven fabrics, in which the ultraviolet absorber can be adsorbed by both silk and polylactic acid fiber components at the same time, and the finishing effect has the advantages of high efficiency, durability and little discoloration; the finishing method has the advantages of short process flow, little strength damage to the fabric, and low energy and water consumption.

[0007] The technical solution adopted by the present invention to solve its technical problem is:

[0008] A method for durable ultraviolet protection finishing of a silk / polylactic acid fiber interwoven fabric comprises the following steps:

[0009] (1) preparing a baicalin finishing solution, wherein the baicalin finishing solution comprises baicalin, sodium bisulfite, and a pH adjuster; the pH value of the baicalin finishing solution is controlled at 3.0-3.5;

[0010] (2) Adding silk / polylactic acid fiber interwoven fabric to baicalin finishing liquid, heating the fabric to 100-110°C at a heating rate of 1-2°C / min, and heat-insulating the fabric; after heat-insulating the fabric, cooling the fabric to 60-70°C, washing the fabric with water, and drying the fabric to obtain a silk / polylactic acid fiber interwoven fabric with durable ultraviolet protection function; after washing the silk / polylactic acid fiber interwoven fabric with durable ultraviolet protection function for 15 times, the ultraviolet protection factor UPF is greater than 40, and the UVA transmittance is less than 5%, which meets the technical index requirements of ultraviolet protection products in GB / T18830-2009 "Evaluation of Ultraviolet Protection Performance of Textiles".

[0011] The finishing method provided by the invention can overcome the shortcomings of conventional ultraviolet protection finishing, such as the need to use two kinds of water-soluble and water-insoluble synthetic ultraviolet absorbers to finish the silk and polylactic acid fiber components respectively, resulting in high ultraviolet absorber costs, a long process flow caused by the two-bath two-step finishing method, easy reduction in fabric strength, and high energy and water consumption. It can also overcome the difficulties in conventional synthetic ultraviolet absorber finishing in simultaneously meeting the requirements of two technical indicators of UPF>40 and UVA ultraviolet transmittance<5%.

[0012] Preferably, the amount of baicalin is 4-6% owf.

[0013] Preferably, the concentration of sodium bisulfite in the baicalin finishing solution is 2-4 g / L.

[0014] Preferably, the pH adjuster is citric acid.

[0015] Preferably, the heat preservation treatment time is 40-60 minutes.

[0016] Preferably, in the silk / polylactic acid fiber interwoven fabric, the weight percentage of silk is 30-70%, and the weight percentage of polylactic acid fiber is 30-70%.

[0017] The principle of the present invention is to use a UV absorber that can be simultaneously adsorbed on the silk and polylactic acid fiber components in the silk / polylactic acid fiber interwoven fabric to finish the silk / polylactic acid fiber interwoven fabric, so as to give the silk / polylactic acid fiber interwoven fabric ultraviolet protection performance. For the ultraviolet protection finishing of the silk / polylactic acid fiber interwoven fabric, the ultraviolet absorber used must have good adsorption performance on both silk and polylactic acid fibers to ensure that the silk / polylactic acid fiber interwoven fabric obtains a good ultraviolet protection effect. Baicalin derived from plant extracts has good absorption in the 260-350 nm ultraviolet band, and has two absorption peaks at 274 nm and 316 nm respectively. The absorption band covers the main ultraviolet band range of UV-A (320-380 nm) and UV-B (280-320 nm), so it can be used as an ultraviolet absorber.

[0018] The inventors have found through research that baicalin can be adsorbed by both silk and polylactic acid fiber components at the same time, so it can give both silk and polylactic acid fiber ultraviolet protection properties. In order to ensure that baicalin does not affect the adsorption amount on polylactic acid fiber due to the increase in solubility caused by the ionization of its carboxyl group, and at the same time ensure that it has a sufficient adsorption amount on polylactic acid fiber to provide a good ultraviolet protection effect, the present invention adjusts the pH value of the baicalin finishing solution to 3.0-3.5. Because baicalin has a high affinity for both silk and polylactic acid fibers under this condition, the silk / polylactic acid fiber interwoven fabric finished with baicalin has good washing resistance. Even if baicalin is desorbed on one of the fibers during washing, it can ensure that the silk / polylactic acid fiber interwoven fabric still has a sufficiently good ultraviolet protection function after washing. The finishing and dyeing of polylactic acid fibers by small molecule compounds (such as ultraviolet absorbers and disperse dyes) often need to be carried out at high temperatures, but baicalin has poor stability at high temperatures. The higher the temperature, the worse the stability of baicalin. Baicalin is easy to change color due to oxidation at high temperatures, making the finished fabric darker in color, thereby affecting the appearance. The stability of baicalin under acidic conditions is significantly better than that under neutral and alkaline conditions. For this reason, in addition to adjusting the pH value of the baicalin finishing liquid to 3.0-3.5, the present invention also specifically adds sodium bisulfite as a reducing agent and an antioxidant to eliminate the oxidation of baicalin by oxygen in the water of the finishing liquid and inhibit the self-oxidation of baicalin at high temperatures. Moreover, sodium bisulfite, as a reducing agent, has a certain degree of bleaching effect on the oxidation products of baicalin. At the same time, the pH value regulator uses citric acid, which also has a certain antioxidant effect. In summary, the present invention can effectively inhibit baicalin from oxidative discoloration at high temperature by adding sodium bisulfite and citric acid to the baicalin finishing solution, thereby ensuring that baicalin has a high adsorption amount on both silk and polylactic acid fibers, thereby giving the silk / polylactic acid fiber interwoven fabric a durable ultraviolet protection effect, and the degree of discoloration of the finished interwoven fabric is very small.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The baicalin used in the present invention is a plant extract, and using it as an ultraviolet absorber for textiles has the advantages of being eco-friendly and safe, and conforms to the development direction of ecological textiles and ecological dyeing and finishing processing technology.

[0021] The ultraviolet absorber - baicalin in the present invention can give the silk / polylactic acid fiber interwoven fabric good ultraviolet protection performance. The ultraviolet protection finishing method of the present invention has the advantages of short process flow, small damage to fabric strength, and low energy and water consumption. It overcomes the disadvantages of conventional ultraviolet protection finishing that requires the use of two kinds of water-soluble and non-water-soluble synthetic ultraviolet absorbers to finish the silk and polylactic acid fiber components respectively, which causes high cost of ultraviolet absorbers, and the use of two-bath two-step finishing method causes a long process flow, easy reduction of fabric strength, and high energy and water consumption.

[0022] The silk / polylactic acid fiber interwoven fabric obtained by the technical method of the present invention has a very small degree of discoloration.

[0023] Using baicalin as an ultraviolet absorber for silk / polylactic acid fiber interwoven fabrics can overcome the problem that conventional synthetic ultraviolet absorber finishing is difficult to simultaneously meet the requirements of two technical indicators: UPF>40 and UVA transmittance<5%.

[0024] The silk / polylactic acid fiber interwoven fabric obtained by the technical method of the present invention still meets the technical index requirements of ultraviolet protection factor (UPF)>40 and UVA transmittance<5% for ultraviolet protection products specified in GB / T18830-2009 "Evaluation of ultraviolet protection performance of textiles" even after being washed 15 times. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The ultraviolet protection factor UPF and UVA transmittance (T UVA ). DETAILED DESCRIPTION

[0026] The technical solution of the present invention is further described in detail below through specific embodiments.

[0027] In the present invention, unless otherwise specified, the raw materials and equipment used can be purchased from the market or are commonly used in the art. The methods in the following embodiments, unless otherwise specified, are all conventional methods in the art.

[0028] Example 1

[0029] The method comprises the following steps: preparing a 4% owf (relative percentage to fabric mass) baicalin and a 4 g / L sodium bisulfite aqueous solution, adjusting the pH to 3.0 with citric acid, adding the solution to the silk / polylactic acid fiber interwoven fabric, heating the solution to 110°C at a heating rate of 2°C / min, and heat-preserving the solution for 60 minutes; after heat-preserving the solution, cooling the solution to 70°C, washing the solution with water, and drying the solution to obtain a silk / polylactic acid fiber interwoven fabric with a durable ultraviolet protection function.

[0030] The color parameters of the finished silk / polylactic acid fiber interwoven fabric were tested. The lightness L* of the finished fabric was 80.10, the red-green index a* was 3.01, the yellow-blue index b* was 10.65, and the whiteness index WI was 75.2. However, the L*, a*, b* and WI of the unfinished fabric were 88.11, 2.18, 7.87 and 83.3 respectively. The color difference △E of the fabric before and after finishing was 13.27. The finished fabric was only slightly stained, indicating that the discoloration of the finished fabric was very small.

[0031] The finished silk / polylactic acid fiber interwoven fabric was subjected to a wash durability test, and the washing method was as follows: washing in 2 g / L silk and wool detergent at 40°C for 1 time, 2 times, 5 times, 10 times, and 15 times, and each washing time was 30 min.

[0032] The UV protection factor (UPF) and UVA transmittance (T) of unfinished interwoven fabrics and unwashed and washed interwoven fabrics were measured by UV-2000F ultraviolet transmission analyzer (Labsphere, USA). UVA ). The UPF and UVA transmittance of the unfinished interwoven fabric were 9.1 and 21.22% respectively, and the UV protection performance was very poor. Figure 1 It can be seen that the UPF and UVA transmittance of the unwashed finished interwoven fabric are 174.1 and 1.86% respectively, which meet the technical index requirements of UPF>40 and UVA transmittance <5% for UV protection products specified in GB / T 18830-2009 "Evaluation of UV protection performance of textiles". As the number of washings increases, the UPF gradually decreases and the UVA transmittance gradually increases. However, after 15 washes, the UPF and UVA transmittance of the finished interwoven fabric are 68.8 and 3.33% respectively, which still meet the technical index requirements of UPF>40 and UVA transmittance <5% for UV protection products specified in GB / T 18830-2009 "Evaluation of UV protection performance of textiles".

[0033] Example 2

[0034] Baicalin was used as an ultraviolet absorber to finish a silk / polylactic acid fiber interwoven fabric (70% silk and 30% polylactic acid fiber), including the following steps: preparing an aqueous solution of 6% owf (relative percentage to fabric mass) baicalin and 2 g / L sodium bisulfite, adjusting the pH to 3.5 with citric acid, adding the silk / polylactic acid fiber interwoven fabric, heating it to 100°C at a heating rate of 1°C / min, and heat-treating it for 40 minutes; after heat-treating it, cooling it to 70°C, washing it with water, and drying it to obtain a silk / polylactic acid fiber interwoven fabric with durable ultraviolet protection function. The UPF and UVA transmittance of the finished interwoven fabric were 185.3 and 1.57%, respectively.

[0035] The finished silk / polylactic acid fiber interwoven fabric was subjected to a wash durability test, and the washing method was as follows: washing 15 times at 40°C in 2 g / L silk and wool detergent, each washing time was 30 min. After 15 washes, the UPF and UVA transmittance of the finished interwoven fabric were 74.6 and 3.15% respectively, which still met the technical index requirements of UPF>40 and UVA transmittance <5% for UV protection products specified in GB / T 18830-2009 "Evaluation of UV protection performance of textiles".

[0036] Comparative Example 1

[0037] In this example, no sodium bisulfite was added, and other conditions were the same as those in Example 1.

[0038] The color parameters of the finished silk / polylactic acid fiber interwoven fabric were tested. The lightness L* of the finished fabric was 74.59, the red-green index a* was 4.01, the yellow-blue index b* was 18.77, the whiteness index WI was 65.5, and the color difference △E of the fabric before and after finishing (i.e., the color difference between the finished fabric and the unfinished fabric) was 17.46. The whiteness of the finished fabric in this comparative example is lower than that of the finished fabric in Example 1, the color difference value is higher than the color difference of the finished fabric in Example 1, and the b* value is significantly higher than the b* value of the finished fabric in Example 1, indicating that the degree of discoloration of the finished fabric obtained is large when sodium bisulfite is not added to the finishing liquid. The comparison results of Comparative Example 1 and Example 1 show that the addition of sodium bisulfite in the finishing liquid is beneficial to reducing the degree of discoloration of the finished fabric.

[0039] Comparative Example 2

[0040] The water-soluble synthetic ultraviolet absorber UV-fast W (benzotriazole) is used to finish a silk / polylactic acid fiber interwoven fabric (including 30% silk and 70% polylactic acid fiber), comprising the following steps: preparing a 4% owf (relative percentage to fabric mass) UV-fast W aqueous solution, adjusting the pH to 3.5 with citric acid, adding the silk / polylactic acid fiber interwoven fabric, heating the fabric to 110°C at a heating rate of 2°C / min, and heat-keeping for 60 minutes; after the heat-keeping treatment, cooling the fabric to 70°C, washing the fabric with water, and drying the fabric to obtain the finished silk / polylactic acid fiber interwoven fabric.

[0041] The UPF and UVA transmittance of the finished interwoven fabric were 104.2 and 6.07% respectively, which could not meet the technical index requirements of UPF>40 and UVA transmittance <5% for UV protection products specified in GB / T18830-2009 "Evaluation of UV protection performance of textiles". After 15 washes, the UPF and UVA transmittance of the finished interwoven fabric were 14.4 and 14.72% respectively, which even more failed to meet the technical index requirements of UPF>40 and UVA transmittance <5% for UV protection products specified in GB / T 18830-2009 "Evaluation of UV protection performance of textiles".

[0042] Comparative Example 3

[0043] The method comprises the following steps: preparing a 4% owf (relative percentage to fabric mass) UV-fast P aqueous dispersion, adjusting the pH to 3.5 with citric acid, adding the silk / polylactic acid fiber interwoven fabric, heating the fabric to 110°C at a heating rate of 2°C / min, and heat-keeping the fabric for 60 minutes; after heat-keeping the fabric, cooling the fabric to 70°C, washing the fabric with water, and drying the fabric to obtain the finished silk / polylactic acid fiber interwoven fabric.

[0044] The UPF and UVA transmittance of the finished interwoven fabric were 183.5 and 4.06% respectively, which can meet the technical index requirements of UPF>40 and UVA transmittance <5% for anti-ultraviolet products specified in GB / T18830-2009 "Evaluation of the UV protection performance of textiles". However, after 15 washes, the UPF and UVA transmittance of the finished interwoven fabric were 110.0 and 5.77% respectively, which did not meet the technical index requirements of UPF>40 and UVA transmittance <5% for anti-ultraviolet products specified in GB / T 18830-2009 "Evaluation of the UV protection performance of textiles".

[0045] Comparative Example 4

[0046] A water-soluble synthetic UV absorber UV-fast W (benzotriazole) and a water-insoluble synthetic UV absorber UV-fast P (triazine) are mixed to finish a silk / polylactic acid fiber interwoven fabric (30% silk and 70% polylactic acid fiber), comprising the following steps: preparing a mixed solution of 2% owf (relative percentage to fabric mass) UV-fast W and 2% (relative percentage to fabric mass) UV-fast P (the total amount of UV absorber is 4%), adjusting the pH to 3.5 with citric acid, adding the silk / polylactic acid fiber interwoven fabric, heating the fabric to 110°C at a heating rate of 2°C / min, and heat-keeping for 60 minutes; after the heat-keeping, cooling the fabric to 70°C, washing the fabric with water, and drying the fabric to obtain a finished silk / polylactic acid fiber interwoven fabric.

[0047] The UPF and UVA transmittance of the finished interwoven fabric were 270.2 and 3.98% respectively, which met the technical index requirements of UPF>40 and UVA transmittance <5% for UV protection products specified in GB / T 18830-2009 "Evaluation of UV protection performance of textiles". However, after 15 washes, the UPF and UVA transmittance of the finished interwoven fabric were 90.3 and 6.93% respectively, which did not meet the technical index requirements of UPF>40 and UVA transmittance <5% for UV protection products specified in GB / T 18830-2009 "Evaluation of UV protection performance of textiles".

[0048] The above embodiments, comparative examples and accompanying drawings show that the technical scheme of the present invention uses baicalin as an ultraviolet absorber to finish the silk / polylactic acid fiber interwoven fabric. The UPF and UVA transmittance of the finished silk / polylactic acid fiber interwoven fabric after 15 washings still meet the technical index requirements of UPF>40 and UVA transmittance <5% for ultraviolet protection products specified in GB / T 18830-2009 "Evaluation of Ultraviolet Protection Performance of Textiles", showing durable ultraviolet protection performance, and the degree of discoloration of the finished interwoven fabric is very small.

[0049] The above-described embodiment is only a preferred solution of the present invention and does not limit the present invention in any form. There are other variations and modifications without exceeding the technical solution described in the claims.

Claims

1. A method for durable ultraviolet protection finishing of silk / polylactic acid fiber interwoven fabrics, characterized in that: The following steps are involved: (1) preparing a baicalin finishing solution, wherein the baicalin finishing solution comprises baicalin, sodium bisulfite, and a pH adjuster; the pH value of the baicalin finishing solution is controlled at 3.0-3.5; (2) adding silk / polylactic acid fiber interwoven fabric to the baicalin finishing solution, heating the mixture to 100-110°C at a heating rate of 1-2°C / min, and heat preservation; After the heat preservation treatment, the temperature is lowered to 60-70°C, and the silk / polylactic acid fiber interwoven fabric with durable ultraviolet protection function is obtained through water washing and drying. After the silk / polylactic acid fiber interwoven fabric with durable ultraviolet protection function is washed 15 times, the ultraviolet protection factor UPF>40 and the UVA ultraviolet transmittance <5%, which meets the technical index requirements of ultraviolet protection products in GB / T18830-2009 "Evaluation of ultraviolet protection performance of textiles"; The dosage of baicalin is 4-6% owf; in the baicalin finishing solution, the concentration of sodium bisulfite is 2-4 g / L; and the pH regulator is citric acid.

2. The method according to claim 1, characterized in that The insulation treatment time is 40-60 minutes.

3. The method according to claim 1, characterized in that In the silk / polylactic acid fiber interwoven fabric, the weight percentage of silk is 30-70%, and the weight percentage of polylactic acid fiber is 30-70%.

4. A silk / polylactic acid fiber interwoven fabric with durable ultraviolet protection function prepared by the method according to any one of claims 1 to 3.

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