Anti-UV finishing of cotton fabric
Anti-UV finishing of cotton fabric
Abstract: The padding method was used to perform UV protection/softening finishing and UV protection/iron-free same-bath finishing on pure cotton fabrics. The effects of UV protection finishing agent UA-20 dosage, processing method, fluorescent whitening agent and other factors on the fabric’s UV protection were studied. effect. The test results show that the UV protection ability of the fabric after finishing has been significantly improved, and it can withstand 50 times of washing. The sun fastness of the dyed fabric has also been improved.
Foreword
Excessive exposure to ultraviolet rays will increase melanin, dry and aging skin, and may even induce skin cancer in severe cases. Therefore, anti-UV textiles are increasingly favored by consumers. Anti-UV finishing agents can be divided into two categories: UV absorbers and UV reflectants. The former mainly absorbs ultraviolet rays and converts its energy into heat energy or electromagnetic waves with shorter wavelengths, thereby achieving the purpose of preventing ultraviolet radiation; the latter mainly uses fine powders such as ceramics or metal oxides to combine with fibers or fabrics. It increases the reflection and scattering of ultraviolet rays on the fabric surface, thereby playing a protective role, but it cannot convert light energy.
At present, the anti-UV finishing agents for pure cotton fabrics on the market are mainly UV absorbers, whose main components are benzotriazole, benzophenone and o-hydroxybenzene-diphenyltriazole derivatives . In this experiment, the polymer anti-UV finishing agent UA-20 was added to the soft finishing and no-iron finishing baths of cotton fabrics to finish the fabrics in one bath, and the effects of finishing agent dosage, processing methods, fluorescent whitening agents and other factors on the anti-UV finishing were discussed. effect. UA-20 can form a soft film on the surface of the fabric, has good adhesion to the fiber, and has excellent water resistance.
1Test
1.1 Fabrics and pharmaceutical fabrics 11.7t jade × 11.7tex 566.9 strands/10cmx Received date: 2010-03-24 About the author: Zhang Jianxiang (1968), male. Director of the Technology Center, mainly responsible for the company’s product research and development and quality management. 275. 6 pieces/10cm whitened and unwhitened pure cotton fabrics, which have been pre-treated; other pure cotton fabrics of different colors. Pharmaceutical low-formaldehyde resin finishing agent F-ECO and catalyst FM (BASF), fiber protective agent HDP (Clariant), soft
Agent DT-50B (Federal Cote Company), anti-UV finishing agent UA-20 (Zhejiang Rihua Company).
1.2 Instruments
Rapid padding machine (Ruibi Dyeing Testing Machine Co., Ltd.), continuous tenter setting testing machine (Japan Mikai Dyeing Machine Co., Ltd.), UV-1000F ultraviolet transmittance tester (Labsphere Company of the United States), sun fast Degree tester (SDLArias company).
1.3 Finishing process
1.3.1 UV-proof, soft and bath finishing prescription/(g/L)
Softener DT-50B20
Anti-UV finishing agent UA-20ming
Process flow: two dipping and two rolling finishing solutions (padding rate 65%)_drying (90℃×70s)
1.3.2 UV protection, no ironing and finishing in the same bath
Prescription/(g/L)
Resin finishing agent F—ECO100
Catalyst FM30
Fiber Protective Agent HDP30
Softener DT50B20
Anti-UV finishing agent UA-20 mushroom
Process flow: two dips and two rolling finishing solutions (padding rate 65%) + drying (90℃×708)_baking (150℃×3rain)
1.4 Test methods
The anti-ultraviolet performance is tested in accordance with GB/T18830-2002 (Evaluation of anti-ultraviolet performance of textiles), and the UV.1000F ultraviolet transmittance tester is used to test the knock value and other parameters; the sun fastness is in accordance with AATCC16E-2003 “Light Fastness and Color Fastness” br />
Degree》test.
2Results and Discussion
2.1 Effect of the dosage of anti-UV finishing agent UA-20. The dye is selective in absorbing light. The light absorption of some dyes can extend into the ultraviolet wavelength range, thereby improving the UV protection properties of the fabric. In order to avoid the influence of dye type on the test results, white fabric was used in the test. Take different amounts of anti-UV finishing agent UA-20, and use whitened cotton fabrics to finish according to the process in Section 1.3.1. The relationship between the amount of UA-20 and the slump value of cotton fabrics can be seen from Figure 1. With the UV protection When the dosage of finishing agent UA-20 is increased from 5g/L to 30g/L, the u value of cotton fabric gradually increases, and the UV protection effect is significantly improved; when the dosage of UA-20 is 30 to 50g/L, the UPF value has reached above 30 , but the increase is small. This is because UA. 20 is a water-dispersed polymer UV absorber. It does not have functional groups that can react with hydroxyl groups on cellulose fibers. It is adsorbed on the fiber surface to give the fabric excellent UV protection effect. UA-20 has a large adsorption capacity on cotton fabrics. Beyond this adsorption capacity, it will be difficult to combine with fibers. The same goes for UV protection and no-iron finishing. Considering the production cost and UV protection effect, the optimal dosage of UV protection finishing agent UA-20 is 30∥L.
2.2 The impact of processing methods on UV protection effect
Use whitened cotton fabrics to perform UV-proof/non-ironing and UV-proof/soft same-bath finishing according to the process in Section 1.3. The effects of different processing methods on the UV-proof finishing effect are examined, as shown in Figure 2. It can be seen from Figure 2 that when the amount of anti-UV finishing agent UA-20 is less than 10g/L, the anti-UV effect of non-iron finishing fabrics is higher than that of soft finishing fabrics; when the dosage of UA-20 is greater than 10g/L, the anti-UV effect of soft finishing fabrics is better better. When the dosage of UA-20 is low, the initial shrinkage of the no-iron finishing resin can covalently bond with the hydroxyl groups on the adjacent cellulose molecular chains. Figure 2 The UV protection effects of soft finishing and no-iron finishing are combined, and the adjacent The macromolecular chains are connected to each other, limiting the relative slippage of fiber molecules, thereby reducingThe gaps inside the small fiber molecules reduce the transmittance of ultraviolet rays. Since the affinity of UA-20 to fibers is better than that of resin to fibers, as its dosage increases, the dose of anti-UV finishing fixed on the soft finishing fabric is higher, so the UV protection effect is better.
2.3 The influence of fluorescent whitening agent on the anti-ultraviolet effect. Whitened and non-whitened fabrics with the same tissue specifications were selected, and the anti-ultraviolet/softening bath finishing was carried out respectively. The effect of the fluorescent whitening agent on the anti-ultraviolet effect was investigated. See table 1. Table 1 Effect of fluorescent whitening agent on UV protection effect of fabrics UA-20 dosage Unwhitened fabric Whitened fabric
／(∥L)UPFUVA／%UVB／%UPFUVA／%UVB／%
1012.2l7.377.8516.353.187.7l
2024.153.275.9826.972.0r75.85
3033.163.194.8536.781.954.70
It can be seen from Table 1 that the UPF value of whitened fabrics is 2-4 higher than that of non-whitened fabrics, the ultraviolet transmittance in the UVA band (400-320nm) decreases more, and the UVB band (320-280nm) changes slightly. Fluorescent whitening agents can absorb ultraviolet rays below 400nm, and their maximum absorption wavelength is 360-380nln (located in the UVA band). Therefore, the anti-ultraviolet effect of fabrics after whitening is higher, and the transmittance of the UVA band is lower than that of the UVB band. Fluorescent whitening agents can convert absorbed energy and radiate purple or blue fluorescence of 400 to 500nm, giving the fabric a whitening effect.
2.4 Washing resistance of UV-resistant fabrics
According to the process in Section 1.3, perform UV-proof/no-iron same-bath finishing and UV-proof/soft same-bath finishing on the whitening fabric respectively. The dosage of anti-UV finishing agent UA-20 is 30g/L. The washability of the finished fabrics after washing for different times was measured. The changes in the UV protection effect after washing were similar. That is, the UV protection effect improved when washed 5 times and the UPF value increased. After that, the UPF value gradually decreased. After washing 30 times, the UPF value gradually decreased. tend to level off. This is because the fibers of the fabric are stretched during processing and shrink after washing. After shrinking, the density and tightness of the fabric increase, the porosity of the fabric decreases, and the transmitted ultraviolet rays decrease, so the ultraviolet protection effect becomes better after five washes. As the number of washes increases, the UV-resistant finishing agent that is not firmly bound is washed away, and the UV-resistant effect of the fabric gradually becomes worse. After 50 times of washing, the UPF values of soft-finished and non-iron-finished fabrics dropped by 7.4% and 5.8% respectively, both of which were within the acceptable range.
2.5 Sunlight fastness
The process in Section 1.3 was used to finish the pure cotton fabrics of different colors respectively. The effects of UV protection finishing on the light fastness of the fabrics are shown in Table 2. Table 2 Comparison of light fastness of different finishing methods/grade pure cotton fabric Ordinary soft finishing with anti-UV + soft finishing with anti-UV + no-iron finishing
Blue 343／4
Red 3/4A, S4
Purple 3/44, s4
White 23/43
Gray 2/343/4
Its color can be improved by one level, and the sun fastness of UV-resistant and soft same-bath finishing fabrics is better than that of UV-proof/non-iron finishing. This may be due to the fact that after ultraviolet finishing, the anti-UV finishing agent fixed on the fiber absorbs and reflects ultraviolet rays, and exchanges energy to release or consume the energy with heat or other harmless low-energy radiation to avoid photochemical reactions of the dye. , thus improving the sun fastness (1) When the amount of UV protection and soft and easy-iron finishing is less than 10g/L, the UV protection effect of UV protection/non-iron and soft bath finishing is better than that of anti-UV/soft and non-iron finishing. Bath finishing; when the dosage is greater than 10g/L, the effect of UV protection/softening with bath finishing is better. (2) Anti-UV/soft same-bath finishing fabrics and anti-UV/non-iron same-bath finishing fabrics have better water resistance. After 50 times of washing, their UPF values only dropped by 7.4% and 5.8% respectively. (3) Fluorescent whitening agents can improve the UV protection effect of fabrics; UV protection finishing can improve the 13 light fastness of fabrics kezfZNUEi
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