阅读说明：本技术 一种抗紫外抗氧化整理剂及其制备方法和应用 (Anti-ultraviolet and anti-oxidation finishing agent and preparation method and application thereof ) 是由 苏静 王鸿博 李楠楠 傅佳佳 于 2020-12-14 设计创作，主要内容包括：本发明公开了一种抗紫外抗氧化整理剂及其制备方法和应用,属于功能整理剂技术领域。本发明将香草醛溶解在醋酸盐缓冲液中,然后加入特定用量绿色生物催化剂漆酶进行反应,反应结束后,分离、收集清液、干燥,黄棕色固体粉末产品。本发明所得新型抗紫外抗氧化整理剂对UVA/UVB均具有强烈的吸收性能(透过率不足1％),抗紫外性能优异。经整理剂整理后棉织物的UPF指数高达124,抗紫外等级评价>50。同时,在1mg/mL的浓度下对ABTS～(.+)和DPPH自由基的清除率分别为90％和70％,具有优异的抗氧化性能。此抗紫外抗氧化整理剂及制备方法在产品包装、户外装备以及功能纺织品等领域具有极高的应用价值和潜力。(The invention discloses an anti-ultraviolet and anti-oxidation finishing agent, and a preparation method and application thereof, and belongs to the technical field of functional finishing agents. Dissolving vanillin in acetate buffer solution, adding a specific dosage of green biocatalyst laccase for reaction, separating, collecting clear liquid, drying and obtaining a yellowish-brown solid powder product after the reaction is finished. The novel ultraviolet-resistant and antioxidant finishing agent has strong absorption performance (the transmittance is less than 1%) on UVA/UVB, and the ultraviolet resistance is excellent. The UPF index of the cotton fabric finished by the finishing agent is up to 124, and the ultraviolet resistance grade evaluation>50. All in oneWhen the concentration is 1mg/mL for ABTS .+ And DPPH free radical clearance rate is 90% and 70%, respectively, and the antioxidant property is excellent. The uvioresistant antioxidant finishing agent and the preparation method thereof have extremely high application value and potential in the fields of product packaging, outdoor equipment, functional textiles and the like.)

1. A method for preparing an ultraviolet-resistant and antioxidant finishing agent is characterized in that in acetate buffer solution, vanillin is used as a substrate, enzymatic reaction is carried out under the catalysis of laccase, solid-liquid separation is carried out after the reaction is finished, liquid is collected, and drying is carried out.

2. The method of claim 1, wherein the enzymatic reaction is represented by the formula:

wherein n is any one or more of 0, 1, 3 and 4.

3. The method according to claim 1 or 2, characterized in that the concentration of the substrate vanillin is between 5 and 25 mg/mL.

4. The method of claim 1 or 2, wherein the laccase is present in an amount of 20-100U/mL.

5. The method of claim 1 or 2, wherein the solvent is an acetate buffer solution; the pH value of the acetic acid buffer solution is 4.0-7.0.

6. The method according to claim 1 or 2, wherein the reaction temperature of the enzymatic reaction is 20 to 60 ℃; the reaction time is 6-30 h.

7. The method according to any one of claims 1 to 6, wherein the concentration of the substrate vanillin is between 10 and 25 mg/mL.

8. An uvioresistant and antioxidative finishing agent prepared by the method of any one of claims 1 to 7.

9. The method for preparing the ultraviolet-resistant and oxidation-resistant fabric is characterized by comprising the following steps of:

adding laccase and fabric into acetate buffer solution with vanillin as substrate, performing enzymatic reaction, centrifuging after the reaction is finished, collecting liquid, and drying.

10. The use of the uv resistant and antioxidant finish of claim 8, or the uv resistant and antioxidant fabric of claim 9 in the field of product packaging, outdoor products, functional textile manufacturing.

Technical Field

The invention belongs to the technical field of functional finishing agents, and particularly relates to an anti-ultraviolet and anti-oxidation finishing agent and a preparation method and application thereof.

Background

Moderate ultraviolet rays are beneficial to human health, and the ozone layer is damaged by environmental pollution caused by the development of industrial society. As the resistance of the atmosphere to ultraviolet rays is weakened, the threat of ultraviolet rays to human beings is increasing. In the natural environment, free radicals do not contribute in a small amount to human health safety and human property safety, in addition to ultraviolet light. Besides the damage to human health, the problems of photo-aging and free radical oxidative aging exist in material synthesis and manufacturing for a long time, ultraviolet rays and free radicals can accelerate the damage and degradation of materials, especially some outdoor use materials, and excessive ultraviolet rays and free radical corrosion can accelerate the aging and color fading of products. Therefore, the novel ultraviolet-resistant and oxidation-resistant finishing agent is developed and added into the production and preparation of materials to produce products with ultraviolet-resistant and oxidation-resistant properties, and has great significance for guaranteeing the health and property safety of human beings.

Disclosure of Invention

In order to solve the problems, the invention provides a method for preparing a novel anti-ultraviolet and anti-oxidation finishing agent, which is prepared by a biological enzyme catalysis technology, namely laccase catalysis reaction is utilized. Laccase is green and environment-friendly multi-copper oxidase, and water, which is the only byproduct generated by oxidizing oxygen in air, is widely concerned due to the characteristic of green and efficient catalytic reaction.

The novel anti-ultraviolet and anti-oxidation finishing agent is obtained by laccase catalytic reaction, is different from the conventional physical/chemical ultraviolet absorption finishing agent, has the unique raw material of vanillin, is derived from natural lignin fiber, has the excellent qualities of no toxicity, no odor, no pollution, no radioactivity and the like, is ecological, is harmless to a human body, belongs to a green and environment-friendly product, and is a renewable resource with extremely high application value. The preparation method is different from the traditional physical and chemical method (complex process, time and labor waste, high pollution and high energy consumption), the preparation process is simple, efficient, green and pollution-free, the one-step enzymatic reaction technology is adopted, and the novel functional finishing agent can be obtained by centrifugally separating and freeze drying the product after the enzymatic reaction is finished.

The invention uses vanillin as a substrate, acetate as a buffer solution and biocatalyst laccase, which belong to the category of environment-friendly industrial raw materials, and the finishing and processing process can be completed only in a vibration reactor. The production and processing of the novel finishing agent are beneficial to the safety and health of ecological environment, and accord with the concept of green economy and sustainable development.

The first purpose of the invention is to provide a method for preparing a novel ultraviolet-resistant and antioxidant finishing agent, which comprises the following steps: performing enzymatic reaction in acetate buffer solution by using Vanillin (Vanillin) as a substrate under the catalysis of Laccase (Lactase), centrifuging after the reaction is finished, collecting liquid, and drying.

In one embodiment of the invention, the enzymatic reaction is represented by the formula:

wherein n is any one or more of 0, 1, 3 and 4.

In one embodiment of the present invention, the reaction process of the enzymatic reaction is as follows:

wherein n is any one or more of 0, 1, 3 and 4.

In one embodiment of the invention, the concentration of the substrate vanillin is between 5 and 25 mg/mL. Preferably 10 to 25mg/mL, and more preferably 20 mg/mL.

In one embodiment of the invention, the laccase is used in an amount of 20-100U/mL. Preferably 40-80U/mL.

In one embodiment of the invention, the acetic acid buffer solution has a pH of 4.0 to 7.0 and a concentration of 1 mM; the optimum pH of the acetate buffer was 5.0.

In one embodiment of the present invention, the enzymatic reaction is carried out with stirring at a speed of 100-500 rpm. The optimum speed is 400 rpm.

In one embodiment of the invention, the reaction temperature of the enzymatic reaction is 20-60 ℃. The optimum reaction temperature is 50 ℃.

In one embodiment of the invention, the reaction time of the enzymatic reaction is 6 to 30 h. The optimal reaction time is 24 h.

In one embodiment of the present invention, after completion of the enzymatic reaction, the obtained reaction system was centrifuged at 6000rpm for 10min in a centrifuge.

In one embodiment of the invention, after centrifugation, the supernatant is collected and then frozen at-4 ℃ for 24h and then dried in a freeze dryer for 12-72 h.

In one embodiment of the present invention, the preparation method specifically comprises the following steps:

s1-enzymatic reaction: completely dissolving a certain amount of vanillin monomers in an acetate buffer solution, and then adding laccase to initiate enzymatic reaction; setting reaction condition parameters that the pH value of an acetate reaction solution is 5.0, the reaction temperature is 50 ℃, the reaction time is 24 hours, and the oscillation rate is 400 rpm;

s2-centrifugation, freeze-drying: after the enzymatic reaction is finished, centrifugally separating the soluble reaction product and the precipitable reaction product in a centrifugal machine at 6000rpm, taking out the soluble reaction product, freezing the soluble reaction product at-4 ℃ for 24 hours, and drying the completely frozen reaction product in a freeze dryer for 12-72 hours to obtain the novel ultraviolet absorption finishing agent.

The second purpose of the invention is to prepare a novel ultraviolet-resistant and oxidation-resistant finishing agent by using the method.

In one embodiment of the present invention, the anti-uv and anti-oxidant finish comprises a compound of the structure:

when n is 0, the reaction product is a dimer, the molecular weight is 302, and the specific structure is shown as follows:

when n is 1, the reaction product is a trimer with a molecular weight of 452, and the specific structure is shown as follows:

when n is 2, the reaction product is a tetramer with the molecular weight of 602, and the specific structure is shown as follows:

when n is 3, the reaction product is a pentamer with a molecular weight of 752, and the specific structure is as follows:

when n is 4, the reaction product is hexamer, the molecular weight is 902, and the specific structure is shown as follows:

the third purpose of the invention is to provide a method for preparing an anti-ultraviolet and anti-oxidation fabric, which comprises the following steps:

adding laccase and fabric into acetate buffer solution with vanillin as substrate, performing enzymatic reaction, centrifuging after the reaction is finished, collecting liquid, and drying.

In one embodiment of the invention, laccase catalyzed polymerization of vanillin is performed simultaneously with the textile finishing, with a reaction time of 24h at 50 ℃ and 400 rpm.

In one embodiment of the invention, the method further comprises: and after the enzymatic reaction is finished, taking the finished cotton fabric out of the reaction system, washing the reaction product with the surface which is not completely combined by deionized water, and then placing the cotton fabric in an oven at 60 ℃ for drying for 4 hours to test the uvioresistant performance of the finished cotton fabric.

The fourth purpose of the invention is to apply the ultraviolet-resistant and oxidation-resistant finishing agent in the fields of product packaging, outdoor products and functional textile manufacturing.

The invention has the beneficial effects that:

the novel ultraviolet-resistant antioxidant finishing agent is prepared by enzymatic reaction, and the thermal test performance shows that the novel finishing agent has stronger thermal stability. Ultraviolet resistance and cytotoxicity tests show that the novel finishing agent can be used as a safe ultraviolet-resistant and antioxidant additive and applied to the fields of product packaging, outdoor equipment, textiles and the like. The novel synthesis and preparation method of the ultraviolet-resistant and antioxidant finishing agent has the advantages of short process flow, convenient treatment, high efficiency, no pollution, high conversion efficiency and one-step enzymatic reaction yield up to 85 percent.

The uvioresistant and antioxidant finishing agent prepared by the invention takes pure cotton fabric as a base material, and carries out uvioresistant performance detection and rating on the finished cotton fabric. After the novel ultraviolet-resistant finishing agent finishes pure cotton fabrics, the finished cotton fabrics have strong absorption performance to both UVA and UVB, wherein the transmittance of UVA is 0.94%, the transmittance of UVB is 0.67%, the UPF index is 124.92, and the ultraviolet-resistant grade evaluation is more than 50.

The ultraviolet-resistant and antioxidant finishing agent prepared by the invention is different from the current domestic common ultraviolet absorbers, such as salicylates, dibenzyl ketones, benzotriazoles and TiO₂And ZnO and the like have the defects of narrow absorption wavelength range, optical toxicity, unknown safety and the like to different degrees. The novel anti-ultraviolet finishing agent of the invention can be used as renewable materialThe raw materials are used as sources, the preparation process accords with the concept of green sustainable development, and the obtained finishing agent has the characteristics of biological safety and no toxicity, and has extremely high application value and potential in the fields of product packaging, outdoor products and textile manufacturing.

Drawings

FIG. 1 is a UV-Vis spectrum of the UV-resistant and antioxidant finishing agent of the present invention during an enzymatic reaction;

FIG. 2 is an infrared spectrum of the anti-UV and anti-oxidant finishing agent of the present invention;

FIG. 3 is an X-ray diffraction pattern of the anti-UV and anti-oxidant finishing agent of the present invention;

FIG. 4 is a graph of a thermal performance test of an ultraviolet resistant and antioxidant finish of the present invention;

FIG. 5 shows ABTS resistance of the anti-UV and anti-oxidation finishing agent of the invention^.+A free radical property profile;

FIG. 6 is a graph of the DPPH free radical resistance of the UV and antioxidant finishing agent of the present invention;

FIG. 7 is a graph of the UV resistance of the UV resistant and antioxidant finishing agent of the present invention;

FIG. 8 is the NMR spectrum of vanillin monomer and the product of example 1.

Detailed Description

The present invention is not limited to the embodiments, and those skilled in the art can make various equivalent modifications or substitutions without departing from the scope of the invention, which is defined by the claims.

The yield referred to below is the mass of the polymerization product/mass of vanillin monomer.

anti-ABTS^.+Testing the free radical property: ABTS solution with the concentration of 7mM and K with the concentration of 2.45mM are prepared respectively₂S₂O₈Solution, 1mL ABTS solution and K are taken respectively₂S₂O₈Storing the solution at room temperature in dark for 12-16h, and measuring the absorbance of the solution at 734nm with enzyme-labeling instrument to be about 0.7 to obtain ABTS^.+And (4) stock solution. Then the finishing agent is addedDissolving in ethanol solvent, and respectively preparing finishing agent solution with concentration of 0.1-1 mg/mL. After 10. mu.L of finishing agent with different concentrations and 200. mu.L of stock solution were reacted for 6 minutes in the dark, the absorbance of the reacted solution was measured at 734nm, which is the absorbance of the experimental group. Equal amount of ethanol solvent was used to replace the finish and equal amount of ABTS^.+The stock solution is reacted for the same time, and the absorbance measured is the absorbance of the control group.

ABTS^.+Free radical clearance (%) - (control absorbance-experimental absorbance)/control absorbance.

DPPH free radical resistance test: weighing DPPH with the concentration of 1mg, dissolving in 10mL of ethanol solvent, storing for 60-120 minutes in a dark place at room temperature, and measuring the absorbance of the solution at 517nm by using a microplate reader to be 1.2-1.3 best, thus obtaining DPPH stock solution. Similarly, the finishing agent is dissolved in ethanol solvent, and finishing agent solutions with the concentration of 0.1-1mg/mL are respectively prepared. After 10. mu.L of finishing agent with different concentrations and 200. mu.L of stock solution were reacted for 30 minutes in the dark, the absorbance of the reacted solution was measured at 517nm, which is the absorbance of the experimental group. The same amount of ethanol solvent was used to replace the finish and the same amount of DPPH stock solution were reacted for the same time, and the absorbance measured was the absorbance of the control.

DPPH free radical clearance (%) (control absorbance-experimental absorbance)/control absorbance.

Example 1

S1-enzymatic reaction: weighing 20mL of acetate buffer solution, weighing 400mg of vanillin, dissolving the 400mg of vanillin in the acetate buffer solution (preparing a vanillin solution with the concentration of 20mg/mL and the pH value of the acetate buffer solution of 5.0), adding laccase to initiate enzymatic reaction (the dosage of the laccase is 80U/mL), and reacting at 50 ℃ and 400rpm for 24 hours;

s2-centrifugation, freeze-drying: after the enzymatic reaction is finished, centrifugally separating the soluble reaction product and the precipitable reaction product in a centrifugal machine at 6000rpm, taking out the soluble reaction product, freezing the soluble reaction product at-4 ℃ for 24 hours, and drying the completely frozen reaction product in a freeze dryer for 72 hours to obtain the novel anti-ultraviolet anti-oxidation finishing agent with the yield of 85%.

And (3) product characterization:

FIG. 8 shows the NMR spectra of vanillin monomer and the resulting finish product, from which FIG. 8 it can be seen that the signal at 7ppm of chemical shift of the reaction product and vanillin monomer is lost, and it is assumed that the hydrogen atom of the phenolic hydroxyl group is involved in the polymerization reaction. The difference in signal at another chemical shift of 7.5ppm of the reaction product compared to vanillin monomer indicates that the aromatic hydrogen atom is involved in the polymerization reaction, and the hydrogen atom on the benzene ring is rearranged to change the signal. The phenolic hydroxyl groups can activate ortho-position and para-position hydrogen atoms, so that the ortho-position hydrogen atoms can participate in the polymerization reaction more easily. The para position of the phenolic hydroxyl group of the vanillin monomer is an aldehyde group, and therefore, in this polymerization reaction, it is stated that a hydrogen atom in the ortho position to the phenolic hydroxyl group should participate in the reaction.

In addition, the molecular weight of the reaction product was further characterized by MALDI-TOF time-of-flight mass spectrometry to verify the guesswork on the structure of the reaction product. The reaction products were predominantly di-hexamers as shown by MALDI-TOF time-of-flight mass spectrometry. Time-of-flight mass spectrometry detected ion fragment peaks at 350, 500, 650, 800 and 950Da, respectively, confirming the material structure guess. The theoretical calculated molecular weights of the 2-6 mer reaction products are 302, 452, 602, 752 and 902Da respectively, and because the time-of-flight mass spectrometry is often accompanied by sodium, potassium and hydrogen peaks in the detection process, the calculation of the molecular weight of the time-of-flight mass spectrometry is usually to increase/decrease the molecular weight of sodium, potassium and hydrogen. Through theoretical calculation, the molecular weights of the reaction products plus the molecular weights of 2 sodium atoms and 2 hydrogen atoms respectively correspond to signal peaks observed on a time-of-flight mass spectrum. According to the hydrogen spectrum of nuclear magnetic resonance and the mass spectrum of time of flight, the reaction product is proved to be a mixture of di-hexamers. The corresponding molecular structures are shown in table 1:

composition structure of ultraviolet-resistant and antioxidant finishing agent obtained in Table 1

And (3) substance characterization:

and (3) characterizing the obtained finishing agent, and detecting the finishing agent by ultraviolet-visible light, infrared rays, X rays and thermal properties:

according to the UV-Vis spectrum shown in FIG. 1, characteristic peaks of vanillin exist in both the 0h group and the laccase-free group. In the laccase group, after 24 hours of reaction, the characteristic peak of vanillin disappeared, and it was assumed that the phenolic hydroxyl group of vanillin reacted with the hydrogen atom at the ortho-position of the phenolic hydroxyl group to form a new reaction product, i.e., vanillin oligomer.

According to the infrared spectrum, the monomer group is obviously different from the reaction product group at 3715 wave numbers (characteristic peak of phenolic hydroxyl group) and 1509-1600 wave numbers (C ═ O stretching vibration peak). The peak shape of the reaction product at 3715 wavenumbers was more gradual and broad, while the peak shape of the monomer group was slightly narrower here. It is presumed that the influence of laccase on the phenolic hydroxyl group is generated after the laccase catalyzed reaction. Likewise, the number of aldehyde groups in the oligomer was greater, and thus the peak shape at 1509-1600 wavenumbers (C ═ O stretching vibration peak) was significantly different from that of the monomer.

According to the XRD diffraction pattern shown in figure 3, the monomer has 2 characteristic peaks at 13 degrees and 39 degrees. The peak intensity of the reaction product at 13 ℃ is reduced, the characteristic peak at 39 ℃ almost disappears, and a new peak is generated between 9 ℃ and 28 ℃. It is assumed that a new reaction product, i.e. vanillin oligomer, is formed after the vanillin monomers have been reacted with the laccase catalysis.

As can be seen from the thermal performance tests of the monomer and the reaction product in FIG. 4, the monomer showed the greatest weight loss at 199 ℃ and was totally degraded at 203 ℃ (carbon residue ratio of 0), indicating poor thermal performance of the monomer. The laccase catalyzed reaction product reaches the maximum weight loss rate at 315 ℃, the carbon residue rate at 800 ℃ is more than 40%, and the improvement of the thermal property of the reaction product is mainly attributed to a benzene ring conjugated structure in an oligomer molecule. The thermal properties of the monomers and reaction products also reflect the formation of vanillin oligomers.

anti-ABTS of monomers and reaction products according to FIG. 5^.+Free radical behavior, monomer and reaction product vs. ABTS^.+Cleaning ofThe rates all increased with increasing concentration, and monomer at a concentration of 1mg/mL versus ABTS^.+The clearance rate of the enzyme is less than 60 percent, and the reaction product catalyzed by laccase has the same concentration to ABTS^.+The clearance rate of the product reaches 90 percent. According to the relevant literature reports, the antioxidant active substance is mainly dependent on its chemical structure, such as the number of active groups and the degree of conjugation of benzene rings. The performance improvement of the reaction product is mainly attributed to the increase of the number of active groups in the oligomer molecule and the conjugated structure of the benzene ring.

As can be seen from the DPPH free radical resistance of the monomers and the reaction products in FIG. 6, the DPPH clearance of the monomers and the reaction products increases with increasing concentration, the DPPH clearance of the monomers is less than 30% at a concentration of 1mg/mL, and the DPPH clearance of the laccase-catalyzed reaction products reaches 80% at the same concentration. Therefore, the laccase is supposed to catalyze the polymerization of the vanillin monomer to generate the oligomer, and the oligomer has excellent oxidation resistance.

As can be seen from the uv resistance of the monomers and reaction products in fig. 7, the reaction products showed weak UVA and UVB transmittances, both less than 1%. Indicating that the reaction product has excellent ultraviolet resistance to both UVA and UVB. The monomer also has lower ultraviolet transmittance at the wavelength of 250-320, while the ultraviolet transmittance at the wavelength of 360-450 is higher. Therefore, the vanillin oligomer generated by the laccase catalytic reaction has more excellent ultraviolet resistance due to the benzene ring conjugated structure.

Example 2: application of uvioresistant finishing agent to textile

S1-enzymatic polymerization finishing of textiles: weighing 20mL of acetate buffer solution, weighing 400mg of vanillin, and dissolving in the acetate buffer solution (preparing vanillin solution with the concentration of 20mg/mL, and the pH value of the acetate buffer solution is 5.0). Pure cotton fabric with a specification of 4cm x 4cm was added, followed by laccase to initiate the enzymatic reaction (laccase dosage 80U/mL). The polymerization of vanillin catalyzed by laccase and the fabric finishing are carried out simultaneously, and the reaction time is 24h at 50 ℃ and 400 rpm.

S2-ultraviolet resistance test of textiles: and after the enzymatic reaction is finished, taking the finished cotton fabric out of the reaction system, washing the reaction product with the surface which is not completely combined by deionized water, and then placing the cotton fabric in an oven at 60 ℃ for drying for 4 hours to test the uvioresistant performance of the finished cotton fabric. The UV resistance of the treated sample cloth was tested in a UV-2000F UV transmissivity analyzer (Labsphere, USA), 5 points were used for testing, and the UPF index, UVA and UVB transmittance of the cotton fabric were automatically calculated by the instrument.

The results of the evaluation of the specific effects are shown in table 2.

TABLE 2 evaluation of the ultraviolet resistance Effect

UPF	T UVA(％)	TUVB(％)	UPF rating	Anti-ultraviolet performance
					124.92	0.94	0.67	>50	Is excellent in

According to table 2, the UPF index of the fabric after finishing with the vanillin reaction product is as high as 124, and the transmittance of both UVA and UVB is less than 1%. According to the national standard GB/T18830-2009 textile ultraviolet resistance evaluation method, the standard specification is that when the ultraviolet protection coefficient UPF is specified>40 and a transmittance T of long-wave ultraviolet rays_UVA<At 5%, it may be called an ultraviolet-proof product. The ultraviolet resistance test shows that the UPF of the fabric finished by the finishing agent is more than 50, T_UVALess than 1 percent, excellent ultraviolet resistance and accordance with the standard.

Example 3: the influence of the substrate concentration on the ultraviolet resistance of cotton fabrics is explored

Referring to example 1, replacing the concentration of vanillin monomer with 3mg/mL, 5mg/mL, 15mg/mL, 20mg/mL, 25mg/mL and 30mg/mL respectively, and the laccase catalyzes vanillin to polymerize on cotton fabric to obtain corresponding ultraviolet-resistant cotton fabric under the same other conditions.

The results of the uv resistance test of the obtained cotton fabric are shown in table 3.

Table 3 results of uv resistance tests on different substrate concentrations finished cotton fabrics

Substrate concentration (mg/mL)	UPF	T UVA(％)	T UVB(％)	UPF rating	Anti-ultraviolet performance
						3	13.42	10.87	5.65	>10	Is free of
5	36.41	2.84	2.01	>30	Good wine
						10	60.13	1.64	1.12	>50	Is excellent in
15	90.56	1.28	0.87	>50	Is excellent in
						20	124.92	0.94	0.67	>50	Is excellent in
25	70.56	1.82	0.94	>50	Is excellent in
						30	30.82	2.98	2.24	>30	Good wine

As is clear from Table 3, the effect of the substrate concentration has an important effect on the enzymatic reaction, and it is considered that, in the appropriate substrate concentration range, increasing the substrate concentration is advantageous in promoting the interaction between the enzyme and the substrate and further promoting the effect of the enzymatic reaction. When the substrate concentration is too high, the activity and stability of the enzyme may be adversely affected due to dense substrate distribution. The combination of the substrate and the laccase active site is not facilitated, and the enzymatic reaction effect is influenced. According to the result of the UV resistance test, 20mg/mL is preferred as the optimum substrate concentration for the enzymatic reaction.

Example 4: the influence of the pH of the acetate solution on the ultraviolet resistance of cotton fabrics is explored

Referring to example 1, the pH of the acetate solution was changed to 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, respectively, and laccase catalyzed vanillin polymerization on cotton fabric to obtain corresponding UV resistant cotton fabric.

The results of the uv resistance test of the obtained cotton fabric are shown in table 4.

Table 4 results of uv resistance test of different acetate pH finished cotton fabrics

As can be seen from Table 4, the pH of the enzymatic reaction system has a significant effect on the enzymatic reaction because the pH may change the conformation of the enzyme molecule. The optimal pH values of laccases from different sources are also different. According to ultraviolet resistance tests, the laccase used in the invention has a good enzymatic reaction effect under acidic conditions. When the reaction system is neutral or alkaline, the uvioresistant performance of the reaction product is continuously reduced. It is speculated that the alkaline environment is not favorable for the extension of the laccase peptide chain or influences the conformation of the laccase molecule. Adversely affecting the activity of laccase and thus the effect of enzymatic reactions. According to the ultraviolet resistance test result, the pH of the buffer solution is preferably 5.0 as the optimum pH value of the enzymatic reaction.

Example 5: the influence of the laccase dosage on the ultraviolet resistance of cotton fabrics is explored

Referring to example 1, the laccase is used for catalyzing vanillin to polymerize on cotton fabrics to prepare corresponding ultraviolet-resistant cotton fabrics by replacing the laccase dosage with 80U/mL, 100U/mL, 60U/mL, 40U/mL, 20U/mL, 10U/mL and 120U/mL respectively and keeping other conditions unchanged.

The results of the uv resistance test of the obtained cotton fabric are shown in table 5.

TABLE 5 UV resistance test results for cotton fabrics finished with different laccase dosages

As can be seen from Table 5, the laccase dosage in the enzymatic reaction system has an important influence on the enzymatic reaction, and the forward reaction is facilitated by properly increasing the laccase dosage. The laccase dosage is too low, the catalytic reaction active site is insufficient, and the substrate is excessive. The laccase dosage is properly increased, so that more catalytic centers and active sites can be provided for a substrate, and the enzymatic reaction effect is facilitated. As the amount of laccase continues to increase, too many enzyme molecules may interfere with or hinder binding to the substrate. Not only waste biological enzyme resources, but also bring adverse effects to the enzymatic effect. According to the ultraviolet resistance test result, the laccase dosage of 80U/mL is preferably selected as the optimal condition of the enzymatic reaction.