Preparation method, product and application of natural tannin grafted chitosan

Abstract

The application provides a preparation method, product and application of natural tano shikimic acid grafted chitosan. The natural tano shikimic acid grafted chitosan with high antibacterial activity, good water solubility and good stability is prepared by grafting natural tano shikimic acid onto chitosan. The preparation method is simple and convenient, has mild reaction conditions, saves energy and reduces consumption, is controllable and has good reproducibility. The prepared natural tano shikimic acid grafted chitosan is used as an antibacterial agent in antibacterial finishing of cellulose fabrics by a layer-by-layer self-assembly method, and the finished fabric with excellent antibacterial performance can be obtained.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of printing and dyeing auxiliaries, and particularly relates to a preparation method, product and application of natural tannoshin grafted chitosan. BACKGROUND

[0002] Cellulose fabrics are favored by consumers due to their skin-friendly and soft properties, but they are prone to bacterial growth. The growth of bacteria can cause cellulose fabrics to produce unpleasant odors, discoloration, degradation and other problems, and can also induce various human diseases. With the enhancement of people's health and environmental protection awareness, the development of ecological antibacterial fabrics is imminent. Correspondingly, the development of efficient and environmentally friendly antibacterial agents has become a research focus.

[0003] Natural antibacterial agents are antibacterial active substances extracted from plants and animals, and have many excellent properties such as safety, non-toxicity, good biocompatibility and wide sources, which meet the green and environmentally friendly development requirements of future antibacterial agents. However, the antibacterial activity of high molecular natural antibacterial agents is weak, and the stability of small molecular natural antibacterial agents is poor. Therefore, it is necessary to develop natural antibacterial agents with high activity and stability.

[0004] Among many natural antibacterial agents, chitosan is the most common natural polymer antibacterial agent, which has good biocompatibility, safety and degradability, and is widely used in the textile industry. However, chitosan only dissolves and exhibits antibacterial activity under acidic conditions, and has weak antibacterial activity against Escherichia coli. This greatly limits the application range of chitosan. In order to improve the antibacterial activity of chitosan, different types of small molecules can be introduced into the molecular structure of chitosan to improve its antibacterial activity and increase its application range. It is of great significance for the development of new natural antibacterial agents to find a small molecule antibacterial agent with high antibacterial activity and low price and introduce it into the structure of chitosan.

[0005] In addition, traditional fabric antibacterial finishing often uses impregnation / immersion, drying, high-temperature baking processes, which have high energy consumption and can easily damage the wearability of the fabric. SUMMARY

[0006] Tannoshin is a natural substance extracted from blueberries, grapes and the like, which contains phenolic hydroxyl groups in its structure and can destroy the cell membrane of bacteria, and has high antibacterial activity. However, tannoshin has poor water solubility and thermal stability, and is not suitable for direct use in the antibacterial finishing of textiles (fabrics).

[0007] To solve the problems in the prior art, the application provides a preparation method of natural tatanic acid grafted chitosan, a product and application, wherein the preparation method adopts small-molecule natural tatanic acid with high activity to graft and modify macromolecular chitosan, the obtained natural tatanic acid grafted chitosan can exert the synergistic antibacterial effect of the two, improves the broad-spectrum antibacterial performance of chitosan, and greatly improves the water solubility and stability of tatanic acid. The product prepared is subjected to layer-by-layer self-assembly to impart excellent broad-spectrum antibacterial property to the fabric under a lower finishing process, and the method is simple in operation, energy-saving and consumption-reducing, and easy to control.

[0008] A preparation method of natural tatanic acid grafted chitosan, comprising:

[0009] Polyformaldehyde is added to an acetic acid aqueous solution of chitosan, stirred until dissolved, and then tatanic acid is added for reaction, after the reaction is completed, the natural tatanic acid grafted chitosan is obtained through post-treatment.

[0010] As preferred, the acetic acid aqueous solution of chitosan is obtained by dissolving chitosan in an acetic acid aqueous solution, and stirring until completely dissolved.

[0011] As further preferred, the concentration of the acetic acid aqueous solution used is 30-50 v / v %.

[0012] As further preferred, the dissolution temperature of chitosan in the acetic acid aqueous solution is 70-90 DEG C.

[0013] As preferred, the concentration of chitosan in the acetic acid aqueous solution is 0.01-0.05 mol / L. Further preferred is 0.01-0.03 mol / L.

[0014] As preferred, the molar ratio of tatanic acid to the repeating structural unit of chitosan is (0.1-0.5):1. Further preferred is (0.1-0.3):1.

[0015] As preferred, the molar ratio of the repeating structural unit in polyformaldehyde to tatanic acid is 1:1.

[0016] As preferred, the reaction temperature after adding tatanic acid is 60-100 DEG C. Further preferred is 70-90 DEG C.

[0017] As preferred, after adding tatanic acid, thin layer chromatography is used to monitor the reaction to the end point.

[0018] As preferred, after the reaction is completed, the following post-treatment is performed:

[0019] After the reaction solution is cooled, diethyl ether is added for extraction to remove unreacted tatanic acid, and then residual diethyl ether is removed by rotary evaporation to obtain the natural tatanic acid grafted chitosan.

[0020] The reaction process of the natural tatanic acid grafted chitosan is as follows:

[0021]

[0022] A natural tano shikimic acid grafted chitosan is prepared by the method described in any of the above. The natural tano shikimic acid grafted chitosan has the advantages of high antibacterial activity, water solubility, good stability, etc. The natural tano shikimic acid grafted chitosan is used as an antibacterial agent in the antibacterial finishing of cellulose fabrics by layer-by-layer self-assembly, and the finished fabric has excellent antibacterial performance.

[0023] Preferably, the grafting rate of the natural tano shikimic acid grafted chitosan is 15-20%. Further preferably, it is 16.7-18.3%.

[0024] The application of the above natural tano shikimic acid grafted chitosan in the antibacterial finishing of fabrics.

[0025] Preferably, the fabric is a cellulose fabric, including cotton, hemp, bamboo, viscose, and their interwoven fabrics, etc.

[0026] Preferably, the fabric antibacterial finishing process comprises the following steps:

[0027] (1) The fabric pretreated with alkali solution is immersed in a polyethyleneimine (PEI) aqueous solution, then washed with water to remove excess polyethyleneimine on the surface, and dried to obtain a polyethyleneimine treated fabric I;

[0028] (2) The fabric I is immersed in a polystyrene sulfonic acid sodium (PSS) aqueous solution at room temperature, then washed with water to remove un-assembled polystyrene sulfonic acid sodium, and dried to obtain a polystyrene sulfonic acid sodium treated fabric II;

[0029] (3) The fabric II is immersed in a natural tano shikimic acid grafted chitosan finishing liquid at room temperature, then washed with water to remove un-assembled natural tano shikimic acid grafted chitosan, and dried to obtain an antibacterial fabric with 1 layer of assembly;

[0030] (4) Steps (2) and (3) are repeated for a certain number of times to obtain an antibacterial fabric with a corresponding number of assembly layers.

[0031] The fabric antibacterial finishing process utilizes the characteristics of the negatively charged layer of polystyrene sulfonic acid sodium and the positively charged layer of natural tano shikimic acid grafted chitosan, and through electrostatic interaction, the polystyrene sulfonic acid sodium and natural tano shikimic acid grafted chitosan with different charges are alternately deposited on the surface of the fabric, so that the fabric has excellent antibacterial performance, the operation is simple, high-temperature baking is not required, the treatment cost is low, and the product performance is good.

[0032] In the above step (1):

[0033] Further preferably, the alkali solution is one or a mixture of two of sodium hydroxide aqueous solution and potassium hydroxide aqueous solution.

[0034] As further preferred, the concentration of the alkali solution is 0.5-1.5 mol / L.

[0035] As further preferred, the bath ratio of the alkali solution pretreatment is 1:(20-40), the pretreatment temperature is 80-100℃, and the pretreatment time is 20-40 min.

[0036] As further preferred, the concentration of the polyethyleneimine aqueous solution is 20-40 g / L.

[0037] As further preferred, the bath ratio of the polyethyleneimine aqueous solution impregnation is 1:(20-40), the impregnation temperature is 60-80℃, and the impregnation time is 80-100 min.

[0038] In the above step (2):

[0039] As further preferred, the concentration of the sodium polystyrene sulfonate aqueous solution is 5-15 g / L.

[0040] As further preferred, the bath ratio of the sodium polystyrene sulfonate aqueous solution impregnation is 1:(40-60), and the impregnation time is 10-30 min.

[0041] In the above step (3):

[0042] As further preferred, the natural tannophore grafted chitosan finishing solution is an aqueous solution of natural tannophore grafted chitosan; wherein the concentration of the natural tannophore grafted chitosan is 10-100 g / L.

[0043] As further preferred, the bath ratio of the natural tannophore grafted chitosan finishing solution impregnation is 1:

[0044] (40-60), and the impregnation time is 10-30 min.

[0045] As preferred, in steps (1)-(3), the drying temperature is independently selected from 70-90℃.

[0046] As further preferred, in step (4), the number of repetitions is set to 1-4 times, and the final obtained antibacterial fabric has 2-5 layers of assembly. More preferably, the number of repetitions is set to 2 times, and the final obtained antibacterial fabric has 3 layers of assembly.

[0047] Compared with the prior art, the present application has the following advantages:

[0048] (1) Compared with chitosan, the natural benzoespirostan grafted chitosan of the application has an antibacterial activity to E. coli increased by more than 90% (minimum inhibitory concentration reduced) and an antibacterial activity to S. aureus increased by more than 60%; the antibacterial rate of the finished fabric to E. coli and S. aureus is as high as 99.9%, the antibacterial rate to E. coli is increased by more than 80% than that of the chitosan finished fabric, and the antibacterial rate to S. aureus is increased by more than 50% than that of the chitosan finished fabric.

[0049] (2) Compared with benzoespirostan, the natural benzoespirostan grafted chitosan antibacterial agent of the application has an improved water solubility, an antibacterial activity to E. coli increased by more than 40%, and an antibacterial activity to S. aureus increased by more than 50%; the antibacterial rate of the finished fabric to E. coli is increased by more than 20% than that of the benzoespirostan finished fabric, and the antibacterial rate to S. aureus is increased by more than 30% than that of the benzoespirostan finished fabric.

[0050] The natural benzoespirostan grafted chitosan with high antibacterial activity, good water solubility and good stability is prepared by grafting the natural benzoespirostan onto chitosan; the preparation method has simple and convenient process, mild reaction condition, energy saving and consumption reduction, strong controllability and good reproducibility. The natural benzoespirostan grafted chitosan prepared is applied to the antibacterial finishing of cellulose fabric as an antibacterial agent through layer-by-layer self-assembly method, and the finished fabric with excellent antibacterial performance can be obtained. BRIEF DESCRIPTION OF DRAWINGS

[0051] Figure 1 The infrared spectra of chitosan (CS), benzoespirostan (PL) and natural benzoespirostan grafted chitosan (PLCS) are shown in the following figure;

[0052] Figure 2 The solubility of PLCS under different pH conditions is shown in the following figure;

[0053] Figure 3 The bacterial growth on the surface of cotton fabric treated with different antibacterial agents is compared in the following figure. DETAILED DESCRIPTION

[0054] The technical solutions of the application are further described below in combination with specific examples. It should be understood that these examples are only used to illustrate the technical solutions of the application and not used to limit the scope of the application. After reading the content taught by the application, those skilled in the art can make various modifications or changes to the application, and these equivalent forms also fall within the scope defined by the claims attached to the application.

[0055] Example 1: Selection of the molar ratio of benzoespirostan to chitosan

[0056] (1) Dissolve 1 mmol of chitosan in 50 mL of 40 v / v% acetic acid aqueous solution, stir at 80°C until completely dissolved to obtain a 0.02 mol / L chitosan solution; prepare five identical chitosan solutions for use;

[0057] (2) Add paraformaldehyde (wherein the molar amount of formaldehyde monomer is 0.1 mmol, 0.2 mmol, 0.5 mmol, 0.75 mmol, and 1 mmol respectively) to the above five chitosan solutions, stir until dissolved, then add corresponding santalwood aldehyde (molar amount is 0.1 mmol, 0.2 mmol, 0.5 mmol, 0.75 mmol, and 1 mmol respectively), control the molar ratio of paraformaldehyde and santalwood aldehyde to be 1:1, react at 80°C, monitor the reaction progress to the end point by thin layer chromatography, and obtain a reaction solution containing natural santalwood aldehyde grafted chitosan;

[0058] (3) After the reaction solution is cooled, add ether to extract unreacted santalwood aldehyde, separate the liquid to obtain a pre-product, and then remove the residual ether by rotary evaporation at room temperature to obtain five different natural santalwood aldehyde grafted chitosans.

[0059] To explore the grafting of santalwood aldehyde on chitosan, the grafting rates of the above five different natural santalwood aldehyde grafted chitosans were calculated, and the results are shown in Table 1.

[0060] Table 1 Grafting rates corresponding to different molar ratios of natural santalwood aldehyde and chitosan

[0061] Molar ratio of chitosan to pyrogallol Grafting ratio (%) 1:0.1 16.7 1:0.2 17.6 1:0.5 18.3 1:0.75 21.0 1:1 21.5

[0062] As can be seen from Table 1, as the amount of santalwood aldehyde increases, the grafting rate of santalwood aldehyde on chitosan gradually increases, and when the molar ratio of santalwood aldehyde to chitosan exceeds 1:0.75, the increasing trend of the grafting rate obviously weakens.

[0063] Figure 1 The infrared spectra of chitosan (CS), santalwood aldehyde (PL), and natural santalwood aldehyde grafted chitosan (PLCS) (molar ratio of chitosan to santalwood aldehyde is 1:0.2). As can be seen from Figure 1, Figure 1 the santalwood aldehyde corresponding to the natural santalwood aldehyde grafted chitosan appears three new characteristic peaks at 2935 cm -1 , 1708 cm -1 , and 891 cm -1 , proving successful grafting.

[0064] The minimum inhibitory concentration of the antibacterial agent was explored by using chitosan, santalwood aldehyde, and the above five different natural santalwood aldehyde grafted chitosans as antibacterial agents respectively, and the results are shown in Table 2. The lower the minimum inhibitory concentration, the higher the antibacterial activity of the antibacterial agent.

[0065] Table 2 Minimum inhibitory concentration of different kinds of antibacterial agents

[0066]

[0067]

[0068] As can be seen from Table 2, with the increase of the amount of natural tannoshin grafted chitosan, the minimum inhibitory concentration of natural tannoshin grafted chitosan to Staphylococcus aureus and Escherichia coli first decreases and then increases, and the minimum inhibitory concentration of natural tannoshin grafted chitosan to the two bacteria is lower than that of chitosan. When the molar ratio of tannoshin to chitosan is (0.1-0.5):1, the minimum inhibitory concentration of natural tannoshin grafted chitosan to the two bacteria is lower; and when the molar ratio of tannoshin to chitosan is 0.2:1, the minimum inhibitory concentration to the two bacteria reaches the lowest, which significantly improves the antibacterial activity of chitosan to Escherichia coli, and the minimum inhibitory concentration is reduced by about 94.8%. This shows that the grafting modification of chitosan by tannoshin can effectively improve the antibacterial activity of chitosan, and exhibits excellent antibacterial performance to Staphylococcus aureus and Escherichia coli.

[0069] Solubility test of PLCS (natural tannoshin grafted chitosan prepared by tannoshin and chitosan with a molar ratio of 0.2:1):

[0070] The antibacterial agent for textiles needs to have good solubility to facilitate the finishing of the fabric, therefore, the solubility of the modified PLCS antibacterial agent is characterized.

[0071] The solubility of PLCS in water and other six commonly used solvents is tested, and compared with CS and PL, and the experimental results are shown in Table 1.

[0072] Table 3 Solubility of CS, PL and PLCS in different solvents

[0073]

[0074] Note: + indicates soluble, ± indicates slightly soluble, and - indicates insoluble.

[0075] As can be seen from Table 3, CS is insoluble in acetone, ethanol and diethyl ether, slightly soluble in water, acetic acid and DMF, and soluble in DMSO. PL is insoluble in water, and soluble in the other six solvents; and PLCS is soluble in the six solvents except diethyl ether. In addition, compared with CS and PL, the solubility of PLCS in water is greatly improved. In the industrial production process, water is the most commonly used solvent, and the good solubility of PLCS in water will help its subsequent application in textile finishing.

[0076] In addition, in order to explore the influence of pH on the solubility of the antibacterial agent in water, the light transmittance of PLCS under different pH conditions was tested by using a UV-visible spectrophotometer, and the test results are shown in Figure 2 As can be seen from Figure 2 , PLCS has good solubility under the condition of pH ranging from 1 to 7, but the water solubility of PLCS rapidly decreases under alkaline conditions. This is consistent with the phenomenon presented by the dissolution state actuality graph in Figure 2 , PLCS is clear and transparent in the aqueous solution with pH of 2, 4 and 6, and the precipitation of PLCS antibacterial agent occurs in the aqueous solution with pH of 8.

[0077] Example 2: Selection of reaction temperature

[0078] (1) 1 mmol of chitosan was dissolved in 50 mL of 40 v / v% acetic acid aqueous solution, and stirred at 80°C until completely dissolved to obtain a 0.02 mol / L chitosan solution. Four identical solutions were prepared and used later;

[0079] (2) 0.2 mmol of paraformaldehyde monomer was added to each of the four solutions, respectively, and stirred until dissolved, and then 0.2 mmol of shikimic acid was added, and reacted at 30°C, 60°C, 80°C, 90°C and 100°C, respectively. The reaction progress was monitored to the end point by using thin layer chromatography to obtain a reaction solution containing natural shikimic acid grafted chitosan;

[0080] (3) After the reaction solution was cooled, ether was added to extract the unreacted shikimic acid, and the pre-product was obtained by extraction, and then residual ether was removed by rotary evaporation to obtain five different natural shikimic acid grafted chitosans.

[0081] The minimum inhibitory concentration of the natural shikimic acid grafted chitosans prepared under the above different reaction temperature conditions was explored, and the results are shown in Table 3.

[0082] Table 3 Influence of different reaction temperatures on the minimum inhibitory concentration of natural shikimic acid grafted chitosan

[0083]

[0084] As shown in Table 3, with the increase of reaction temperature, the minimum inhibitory concentration of natural pterostilbene grafted chitosan antibacterial agent to Staphylococcus aureus and Escherichia coli showed a trend of first decreasing and then increasing. When the temperature was too high (more than 80℃), the minimum inhibitory concentration would increase instead. This may be because when the temperature is too high, the grafting rate increases, and more and more pterostilbene is grafted onto chitosan. However, due to the steric hindrance effect, the antibacterial active sites of pterostilbene cannot be completely exposed, thereby reducing the antibacterial activity. This shows that within a suitable temperature range, the appropriate increase of temperature can promote the grafting modification of pterostilbene on chitosan, thereby effectively improving the antibacterial activity of chitosan. However, the reaction temperature cannot be too high.

[0085] Example 3: Effect of assembly layer number on the antibacterial performance of fabric

[0086] (1) Chitosan (CS) with a unit body molar mass of 1 mmol was dissolved in 50 mL of 40 v / v% acetic acid aqueous solution at 80℃ with stirring until completely dissolved, to obtain a 0.02 mol / L chitosan solution;

[0087] (2) Paraformaldehyde monomer with a molar mass of 0.2 mmol was added and stirred until dissolved, then 0.2 mmol of pterostilbene (PL) was added, and the reaction was carried out at 80℃. The reaction progress was monitored by thin layer chromatography until the end point was reached, to obtain a reaction solution containing natural pterostilbene grafted chitosan;

[0088] (3) After the reaction solution was cooled, diethyl ether was added to extract the unreacted pterostilbene, and the pre-product was obtained by extraction. The residual diethyl ether was removed by rotary evaporation, to obtain natural pterostilbene grafted chitosan (PLCS);

[0089] (4) First, the cotton fabric was immersed in 1 mol / L NaOH solution, and immersed at 90℃ for 30 min with a bath ratio of 1:30. The surface residual NaOH solution was washed away, to obtain a pretreated cotton fabric. The pretreated cotton fabric was immersed in 30 g / L polyethyleneimine (PEI) aqueous solution, and immersed at 70℃ for 90 min with a bath ratio of 1:30. The surface excess PEI was removed by washing, and the PEI cotton fabric was obtained by drying at 80℃;

[0090] (5) Then, the PEI cotton fabric was immersed in 10 g / L sodium polystyrene sulfonate (PSS) solution, and immersed at room temperature for 20 min with a bath ratio of 1:50. The surface excess PSS was removed by washing, and the PSS cotton fabric was obtained by drying at 80℃;

[0091] (6) PSS cotton fabric was immersed in 100 g / L PLCS finishing liquor (solvent: water) at room temperature for 20 min with a bath ratio of 1:50, then washed to remove the un-assembled natural tannin grafting chitosan, and dried at 80 °C to obtain PLCS antibacterial cotton fabric with 1 layer of assembled layers. Five pieces of PLCS antibacterial cotton fabric with 1 layer of assembled layers were prepared simultaneously;

[0092] (7) The PLCS antibacterial cotton fabric with 1 layer of assembled layers obtained in step (6) was repeated for 1 time, 2 times, 3 times and 4 times, respectively, for steps (5) and (6) to obtain PLCS antibacterial cotton fabric with 2 layers, 3 layers, 4 layers and 5 layers of assembled layers.

[0093] According to GB / T20944.3-2008, the antibacterial rate of PLCS finished cotton fabric with different assembled layers was tested, and the results are shown in Table 4.

[0094] Table 4 Effect of different assembled layers on antibacterial rate of PLCS finished cotton fabric

[0095]

[0096] As can be seen from Table 4, when the assembled layer is 1 layer, the antibacterial rate of PLCS cotton fabric against E. coli and S. aureus is 97.1% and 94.9%, respectively. With the increase of self-assembled layers, the antibacterial performance of PLCS cotton fabric is also gradually enhanced. When the self-assembled layer reaches 3 layers, the antibacterial rate of PLCS cotton fabric against E. coli and S. aureus is 99.9%. However, when the assembled layer continues to increase, the antibacterial rate of PLCS cotton fabric against E. coli and S. aureus does not increase, so 3 layers is the most preferred self-assembled layer of antibacterial fabric.

[0097] Figure 3 The antibacterial performance of PLCS finished cotton fabric (self-assembled layer is 3 layers), CS finished cotton fabric (finishing process is the same as PLCS antibacterial finishing), PL finished cotton fabric (finishing process is the same as PLCS antibacterial finishing) and ordinary cotton fabric (untreated cotton fabric) was compared (tested according to GB / T20944.3-2008). From Table 5, it can be seen that the antibacterial performance of PLCS finished cotton fabric is the best, and the antibacterial performance of CS finished cotton fabric is the second best. Figure 3It can be seen that the antibacterial rates of the cotton fabric treated with natural tannoshins grafting chitosan against S. aureus (shown as S. bacteria in the figure) and E. coli (shown as E. bacteria in the figure) can reach more than 99.9%, which is increased by about 56.6% and 89.2% than the antibacterial rates of the cotton fabric treated with chitosan (the antibacterial rates against S. aureus and E. coli are 63.8% and 52.8% respectively) and increased by about 36.2% and 24.7% than the antibacterial rates of the cotton fabric treated with tannoshins (the antibacterial rates against S. aureus and E. coli are 73.3% and 80.1% respectively). This shows that the natural tannoshins grafting chitosan antibacterial agent has excellent antibacterial performance and has broad application prospects in fabric antibacterial finishing.

Claims

1. A natural rosewood-grafted chitosan, characterized in that, It is prepared by the following method: Paraformaldehyde was added to an aqueous acetic acid solution of chitosan and stirred until dissolved. Then, santalinus was added to react. After the reaction was completed, the natural santalinus-grafted chitosan was obtained through post-treatment. The grafting rate of chitosan grafted onto natural rosewood is 15-20%.

2. The natural rosewood-grafted chitosan according to claim 1, characterized in that, The concentration of chitosan in the acetic acid aqueous solution is 0.01~0.05 mol / L.

3. The natural rosewood-grafted chitosan according to claim 1, characterized in that, The molar ratio of pterostilbene to chitosan repeating structural units is (0.1~0.5):1; The molar ratio of repeating structural units in paraformaldehyde to stigma is 1:

1.

4. The natural rosewood-grafted chitosan according to claim 1, characterized in that, The reaction temperature after adding sandalwood is 60~100℃.

5. The application of natural rosewood-grafted chitosan according to any one of claims 1 to 4 in the antibacterial finishing process of fabrics.

6. The application according to claim 5, characterized in that, The antibacterial finishing process for the fabric includes the following steps: (1) The fabric pretreated with alkali solution was immersed in a polyethyleneimine aqueous solution, then washed with water to remove excess polyethyleneimine from the surface, and dried to obtain polyethyleneimine treated fabric I. (2) Immerse fabric I in sodium polystyrene sulfonate aqueous solution at room temperature, then wash with water to remove unassembled sodium polystyrene sulfonate, and dry to obtain sodium polystyrene sulfonate treated fabric II; (3) Immerse fabric II in natural rosewood grafted chitosan finishing solution at room temperature, then wash with water to remove unassembled natural rosewood grafted chitosan, and dry to obtain an antibacterial fabric with 1 assembled layer. (4) Repeat steps (2) and (3) a set number of times to obtain antibacterial fabric with the corresponding number of assembled layers.

7. The application according to claim 6, characterized in that, In step (1), the concentration of the polyethyleneimine aqueous solution is 20~40 g / L; The impregnation bath ratio is 1:(20~40), the impregnation temperature is 60~80℃, and the impregnation time is 80~100min; In step (2), the concentration of the sodium polystyrene sulfonate aqueous solution is 5~15 g / L; The impregnation bath ratio is 1:(40~60), and the impregnation time is 10~30min.

8. The application according to claim 6, characterized in that, In step (3), the natural rosewood grafted chitosan finishing solution is an aqueous solution of natural rosewood grafted chitosan; wherein, the concentration of natural rosewood grafted chitosan is 10~100g / L; The impregnation bath ratio is 1:(40~60), and the impregnation time is 10~30min.

9. The application according to claim 6, characterized in that, In step (4), the number of repetitions is set to 1 to 4 times, and the final number of assembled layers of the antibacterial fabric is 2 to 5 layers.

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