Anion- and cation-modified cellulose fiber nonwoven fabric and preparation method thereof

Abstract

The present invention relates to the technical field of nonwoven fabrics, particularly to the field of IPC D06M13, and more specifically to an anion- and cation-modified cellulose fiber nonwoven fabric and a method for preparing the same. The present invention provides a method for preparing an anion- and cation-modified cellulose fiber nonwoven fabric, comprising the following steps: preparing an alkaline modification solution containing a catalyst, uniformly padding or coating the cellulose fiber nonwoven fabric with the solution through an automatic unwinding process; heating the cellulose fiber nonwoven fabric in the above steps in a drying machine to undergo a reaction and anion- and cation-modification; rinsing the washed and neutralized cellulose fiber nonwoven fabric 4 to 6 times in a washing machine and neutralizing it with acid; and drying, slitting, winding, and packaging the washed and neutralized cellulose fiber nonwoven fabric. The preparation method of the present invention modifies the cellulose fiber nonwoven fabric to impart high transparency and high water absorption.

Description

Technical Field

[0001] The present invention relates to the technical field of nonwoven fabrics, in particular to the field of IPC D06M13, and more specifically to an anion- and cation-modified cellulose fiber nonwoven fabric and a preparation method thereof. Background Art

[0002] Cellulose fiber nonwovens are lightweight, soft, fluffy, and skin-friendly polymer materials. Their molecular chains are easily broken and naturally degrade within a few months of disposal, making them environmentally friendly. The excellent properties of cellulose fiber nonwovens have led to their application in various fields, and modifying the molecular structure of cellulose fibers has become a hot topic.

[0003] Existing patent CN201911151797.4 discloses a tea saponin-modified cellulose fabric for removing chromium ions from water and its preparation method. This method effectively introduces saponin-modified compounds into the cellulose fiber molecular chains, and the carboxyl groups added to the cellulose fiber molecular chains firmly bond with the cellulose fiber molecular chains. The process is simple and can provide deep water purification. However, the selected modifier is single and cannot meet diverse product requirements.

[0004] Existing patent CN202210303410.8 discloses a method for preparing a gelled spunlace nonwoven containing cellulose fibers. The method involves neatly wrapping the cellulose fiber spunlace nonwoven around a porous stainless steel shaft, alkalizing it in a closed device, then etherifying or esterifying it, and finally neutralizing the acid to form carboxymethyl fibers, maintaining a certain strength and integrity. However, the method uses a similar jig-dyeing process, resulting in low production capacity.

[0005] Currently, anionic and cationic modified cellulose is well established on the market. However, the formula and process for direct anionic and cationic modification of cellulose fiber nonwovens are relatively backward, resulting in low production capacity and high energy consumption. Therefore, it is necessary to develop anionic and cationic modified cellulose fiber nonwovens that use multiple modifiers, have highly automated production capabilities, and have stronger adsorption capacity, resulting in high transparency and high water absorption. Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, the first aspect of the present invention provides a method for preparing anion- and cation-modified cellulose fiber nonwoven fabric, comprising the following steps:

[0007] S1: prepare alkaline modifier solution;

[0008] S2: The cellulose fiber nonwoven fabric is unwound automatically, and the solution prepared in the above step S1 is evenly impregnated or coated onto the cellulose fiber nonwoven fabric;

[0009] S3: sending the cellulose fiber nonwoven fabric obtained by the treatment in step S2 into a drying machine for heating reaction to perform anion and cation modification;

[0010] S4: sending the cellulose fiber non-woven fabric after the heating reaction into a washing machine for 4 to 6 times and neutralizing it with acid solution;

[0011] S5: drying, slitting, rolling and packaging the washed and neutralized cellulose fiber non-woven fabric.

[0012] Preferably, the mass of the alkaline modifier solution is 60-100 kg; more preferably, it is 80 kg.

[0013] Preferably, the alkaline modifier solution includes a catalyst, a solvent, and also includes two or more of sodium hydroxide, potassium hydroxide, sodium bicarbonate, halogenated carboxylic acids, various types of glycidyl ethers containing active epoxy groups, 2,3-epoxypropyltrimethylammonium chloride, 3-chloro-2-hydroxypropyltrimethylammonium chloride, 3-chloro-2-hydroxypropyltrimethylammonium chloride cyclopropylcarboxylic acid, and sodium 3-chloro-2-hydroxypropanesulfonate; further preferably, it includes a catalyst, a solvent, and also includes two of sodium hydroxide, halogenated carboxylic acids, 2,3-epoxypropyltrimethylammonium chloride, and 3-chloro-2-hydroxypropyltrimethylammonium chloride.

[0014] Preferably, the catalyst is one or more of ammonia water, ammonium bicarbonate, sodium carbonate, urea, azone, silicone oil, and dimethyl isosorbide; more preferably, it is ammonium bicarbonate.

[0015] Preferably, the alkaline modifier solution comprises, by mass percentage, 1% to 20% ammonium bicarbonate, 3% to 20% sodium hydroxide, 0% to 15% halogenated carboxylic acid, 0 to 8% 2,3-epoxypropyltrimethylammonium chloride, 0 to 8% 3-chloro-2-hydroxypropyltrimethylammonium chloride, and 29% to 96% solvent; further preferably, it comprises 5% to 10% ammonium bicarbonate, 7% to 11% sodium hydroxide, 0% to 8% halogenated carboxylic acid, 0 to 8% 2,3-epoxypropyltrimethylammonium chloride, 0 to 8% 3-chloro-2-hydroxypropyltrimethylammonium chloride, and 45% to 83% solvent.

[0016] Preferably, the halogenated carboxylic acid is one or more of monochloroacetic acid, dichloroacetic acid, and trichloroacetic acid; more preferably, it is monochloroacetic acid.

[0017] Preferably, the solvent comprises one or more of clean water, methanol, ethanol and isopropanol; further preferably, it is one of clean water and an ethanol aqueous solution with a mass fraction of 50%.

[0018] In this application, the applicant unexpectedly discovered that by adding 7% to 11% sodium hydroxide, 0% to 8% halogenated carboxylic acid, 0% to 8% 2,3-epoxypropyltrimethylammonium chloride, 0% to 8% 3-chloro-2-hydroxypropyltrimethylammonium chloride, and 5% to 10% ammonium bicarbonate, the water absorption and transparency of cellulose fiber non-woven fabrics can be improved, and the performance strength can be improved. The applicant speculates that on the one hand, while modifying the surface of the cellulose fiber non-woven fabric, the modification rate of the cellulose fiber non-woven fabric can be accelerated, so that the reaction proceeds gently and evenly. Within a certain period of time, the surface energy of the cellulose fiber non-woven fabric can be modified, reducing the time of the entire reaction, thereby accelerating the modification efficiency of the cellulose fiber non-woven fabric, and then improving the production efficiency of the modified cellulose fiber non-woven fabric. On the other hand, using the small molecule alkaline modifier solution in this ratio can improve the transparency, water absorption and delicate feel of the cellulose fiber non-woven fabric.

[0019] Preferably, the Tencel fiber content of the cellulose fiber non-woven fabric in step S2 is 100%.

[0020] Preferably, the cellulose fiber nonwoven fabric in step S2 is purchased from Hangzhou Nuobang Nonwoven Fabric Co., Ltd.

[0021] Preferably, in step S2, the cellulose fiber nonwoven fabric is automatically unwound into the alkaline modifier solution in step S1 and soaked for 1 to 3 seconds.

[0022] Preferably, in the step S2, the machine for uniformly padding or coating a quantitative amount of the alkaline modifier solution onto the cellulose fiber non-woven fabric is a padder or a coater.

[0023] Preferably, the mass of the cellulose fiber nonwoven fabric in step S2 is 10-40 kg; more preferably, it is 25 kg.

[0024] Preferably, the mass of the alkaline modifier solution impregnated or coated onto the cellulose fiber non-woven fabric in step S2 is 1.5 to 5 times the mass of the cellulose fiber non-woven fabric; more preferably, it is 2 to 4 times.

[0025] Preferably, the automated production line in steps S2 to S5 includes but is not limited to an automatic unwinder, a rolling mill, a drying machine, a washing machine, and an automatic winding machine.

[0026] In the present application, the cellulose fiber nonwoven fabric is immersed in an alkaline modifier solution by an automated unwinding device, and then a padder or coating machine is used to evenly transfer a quantitative alkaline modifier solution to the cellulose fiber nonwoven fabric, and then the fabric enters a drying machine, a washing machine, a drying machine, an automatic winder, and a highly automated production machine, which can reduce energy consumption. The applicant speculates that the cellulose fiber nonwoven fabric can be automatically immersed in an alkaline modifier solution by an automated unwinding device, which reduces manual operation, improves personnel safety, and also improves production efficiency. The cellulose fiber nonwoven fabric is evenly coated with an automated padder or coating machine, which forms a highly automated production line with the subsequent equipment with different functions, improves the coating process for the cellulose fiber nonwoven fabric, increases production capacity, reduces energy consumption, and at the same time, reduces manual participation and reduces the harm of the alkaline modifier solution to the human body.

[0027] Adjust the pressure of the padder or coater so that the mass of the alkaline modifier solution transferred to the cellulose fiber non-woven fabric is 2 to 4 times the mass of the cellulose fiber non-woven fabric. The applicant speculates that if the ratio of the alkaline modifier solution to the cellulose fiber non-woven fabric is less than 2 times, it may result in insufficient modifier on the cellulose fiber non-woven fabric, resulting in the modification effect of the cellulose fiber non-woven fabric not meeting the expectations, thereby reducing the overall performance of the cellulose fiber non-woven fabric. When the ratio of the alkaline modifier solution to the cellulose fiber non-woven fabric is greater than 4 times, it may result in some waste of solution, increase costs, and also volatilize some harmful gases on the automated line, aggravating pollution.

[0028] Preferably, the drying machine in step S3 has a double-sided temperature control function.

[0029] Preferably, the first heating temperature of the drying machine in step S3 is 140-160°C; more preferably, it is 145-155°C.

[0030] Preferably, the second heating temperature of the drying machine in step S3 is 75-125°C; more preferably, it is 80-120°C.

[0031] Preferably, the heating time of the drying machine in step S3 is 50 to 70 seconds; more preferably, it is 55 to 65 seconds.

[0032] In the present application, the drying machine in step S3 has a double-sided temperature control function, which can achieve the heating temperature of the front and back sides of the cellulose fiber non-woven fabric, and obtain products with different or identical modification degrees on the front and back sides. The applicant unexpectedly discovered that temperature can control the modification degree of the non-woven fabric, presenting different characteristics. Under normal circumstances, controlling the temperature of both sides to be the same will cause the highly transparent and highly absorbent modified cellulose fiber non-woven fabric to be equally gelled on both sides. Too high a gel degree on both sides will cause the non-woven fabric to slip easily and reduce adhesion; too low a gel degree will cause the liquid adsorption capacity to decrease. In specific cases, controlling different temperatures on the front and back sides will result in different gel degrees on the front and back sides. Different gel degrees on the front and back sides can effectively balance adsorption and adhesion. Double-sided temperature control can make the gel degrees on the front and back sides different, with one side having a high gel degree and the other side having a low gel degree, so that the high gel side of the modified cellulose fiber non-woven fabric of the present application provides good adsorption capacity and the low gel side provides good adhesion.

[0033] The first heating temperature of the dryer is selected to be 145-155°C, the second heating temperature is selected to be 80-120°C, and the heating time is selected to be 60s, which optimizes the reaction conditions of the modified cellulose fiber non-woven fabric and improves the production capacity of the modified cellulose fiber non-woven fabric. The applicant speculates that if the heating temperature of the dryer is too low or the heating time is too short, the modification may be incomplete and the performance requirements may not be met. Repeated processing may be required, thereby increasing costs. If the heating temperature of the dryer is too high or the heating time is too long, energy will be wasted, and the performance of the cellulose fiber non-woven fabric may also change, failing to meet the performance requirements, thereby resulting in a waste of modifiers.

[0034] Preferably, the temperature of the water in the washing machine in step S4 is 70-90°C; more preferably, it is 80°C.

[0035] Preferably, the acid is one or more of hydrochloric acid, acetic acid, and citric acid; more preferably, it is citric acid.

[0036] Preferably, the citric acid is a 10% citric acid aqueous solution.

[0037] Preferably, the moisture content of the cellulose fiber nonwoven fabric after drying in step S5 is 3-7%; more preferably, it is 5%.

[0038] The second aspect of the present invention provides a cellulose fiber nonwoven fabric obtained by a method for preparing anion- and cation-modified cellulose fiber nonwoven fabric.

[0039] Beneficial effects

[0040] 1. By adding 7% to 11% sodium hydroxide, 0% to 8% halogenated carboxylic acid, 0% to 8% 2,3-epoxypropyltrimethylammonium chloride, 0% to 8% 3-chloro-2-hydroxypropyltrimethylammonium chloride, and 5% to 10% ammonium bicarbonate, the water absorption and transparency of the cellulose fiber non-woven fabric are improved, and the performance strength is improved.

[0041] 2. Through automatic unwinding, rolling or coating, drying in the dryer, cleaning in the washing machine, and automatic rewinding, manual operation can be reduced, automated production can be improved, and energy consumption can be reduced.

[0042] 3. Adjust the pressure of the padder or coater so that the mass of the alkaline modifier solution impregnated or coated on the cellulose fiber non-woven fabric is 2 to 4 times the mass of the cellulose fiber non-woven fabric.

[0043] 4. The drying machine in step S3 has a double-sided temperature control function, which can achieve the heating temperature of the front and back sides of the cellulose fiber non-woven fabric, and obtain products with different or same modification degrees on the front and back sides.

[0044] 5. The first heating temperature of the drying machine is selected to be 145-155°C, the second heating temperature is selected to be 80-120°C, and the heating time is selected to be 60s, which optimizes the reaction conditions of the modified cellulose fiber non-woven fabric and improves the production capacity of the modified cellulose fiber non-woven fabric. DETAILED DESCRIPTION

[0045] Example 1

[0046] In order to overcome the shortcomings of the prior art, the first aspect of the present invention provides a method for preparing anion- and cation-modified cellulose fiber nonwoven fabric, comprising the following steps:

[0047] S1: prepare alkaline modifier solution;

[0048] S2: The cellulose fiber nonwoven fabric is unwound automatically, and the solution prepared in the above step S1 is evenly impregnated onto the cellulose fiber nonwoven fabric;

[0049] S3: The cellulose fiber nonwoven fabric obtained in step S2 is sent to a drying machine for heating reaction to perform anion and cation modification;

[0050] S4: The cellulose fiber nonwoven fabric after the heating reaction is sent to a washing machine for rinsing 5 times and neutralized with acid solution;

[0051] S5: drying, slitting, rolling and packaging the washed and neutralized cellulose fiber non-woven fabric.

[0052] The alkaline modifier solution includes a catalyst, a solvent, sodium hydroxide and a halogenated carboxylic acid.

[0053] The catalyst is ammonium bicarbonate.

[0054] The alkaline modifier solution comprises, by mass percentage, 8% ammonium bicarbonate, 8% sodium hydroxide, 10% halogenated carboxylic acid, and 74% solvent.

[0055] The halogenated carboxylic acid is monochloroacetic acid.

[0056] The solvent is an ethanol aqueous solution with a mass fraction of 50%.

[0057] In the step S2, the Tencel fiber content of the cellulose fiber non-woven fabric is 100%.

[0058] The cellulose fiber nonwoven fabric in step S2 was purchased from Hangzhou Nuobang Nonwoven Fabric Co., Ltd.

[0059] In step S2, the cellulose fiber nonwoven fabric is automatically unrolled into the alkaline modifier solution in step S1 and soaked for 2 seconds.

[0060] In the step S2, the machine for uniformly padding the alkaline modifier solution onto the cellulose fiber non-woven fabric is a padder.

[0061] The mass of the cellulose fiber non-woven fabric in step S2 is 25 kg.

[0062] The mass of the alkaline modifier solution impregnated onto the cellulose fiber non-woven fabric in step S2 is 75 kg.

[0063] The drying machine in step S3 has a double-sided temperature control function.

[0064] The first heating temperature of the drying machine in step S3 is 150°C.

[0065] The second heating temperature of the drying machine in step S3 is 80°C.

[0066] The heating time of the drying machine in step S3 is 60s.

[0067] The temperature of the water in the washing machine in step S4 is 80°C.

[0068] The acid is citric acid.

[0069] The citric acid is a 10% citric acid aqueous solution.

[0070] The moisture content of the cellulose fiber nonwoven fabric after drying in step S5 is 5%.

[0071] This embodiment provides a cellulose fiber nonwoven fabric obtained by a method for preparing anion- and cation-modified cellulose fiber nonwoven fabric.

[0072] Example 2

[0073] The specific implementation of Example 2 is the same as that of Example 1, except that:

[0074] The following steps are involved:

[0075] S1: prepare alkaline modifier solution;

[0076] S2: The cellulose fiber nonwoven fabric is unwound automatically, and the solution prepared in the above step S1 is evenly impregnated onto the cellulose fiber nonwoven fabric;

[0077] S3: The cellulose fiber nonwoven fabric obtained in step S2 is sent to a drying machine for heating reaction to perform anion and cation modification;

[0078] S4: The cellulose fiber nonwoven fabric after the heating reaction is sent to a washing machine for rinsing 5 times and neutralized with acid solution;

[0079] S5: drying, slitting, rolling and packaging the washed and neutralized cellulose fiber non-woven fabric.

[0080] The alkaline modifier solution comprises, by mass percentage, 5% ammonium bicarbonate, 11% sodium hydroxide, 8% 3-chloro-2-hydroxypropyltrimethylammonium chloride, and 76% solvent.

[0081] The solvent is an ethanol aqueous solution with a mass fraction of 50%.

[0082] In step S2, the cellulose fiber nonwoven fabric is automatically unrolled into the alkaline modifier solution in step S1 and soaked for 3 seconds.

[0083] In the step S2, the machine for uniformly coating the alkaline modifier solution onto the cellulose fiber non-woven fabric is a padder.

[0084] The mass of the cellulose fiber nonwoven fabric in step S2 is 40 kg.

[0085] The mass of the alkaline modifier solution impregnated onto the cellulose fiber non-woven fabric in step S2 is 80 kg.

[0086] The first heating temperature of the drying machine in step S3 is 145°C.

[0087] The second heating temperature of the drying machine in step S3 is 100°C.

[0088] The heating time of the drying machine in step S3 is 55 seconds.

[0089] The temperature of the water in the washing machine in step S4 is 90°C.

[0090] The moisture content of the cellulose fiber nonwoven fabric after drying in step S5 is 7%.

[0091] Example 3

[0092] The specific implementation of Example 3 is the same as that of Example 1, except that:

[0093] The alkaline modifier solution comprises, by mass percentage, 10% ammonium bicarbonate, 7% sodium hydroxide, 4% halogenated carboxylic acid, 8% 2,3-epoxypropyltrimethylammonium chloride, and 71% solvent.

[0094] The halogenated carboxylic acid is monochloroacetic acid.

[0095] The solvent is clean water.

[0096] In step S2, the cellulose fiber nonwoven fabric is automatically unwound into the alkaline modifier solution in step S1 and soaked for 1 second.

[0097] The mass of the cellulose fiber nonwoven fabric in step S2 is 10 kg.

[0098] The mass of the alkaline modifier solution impregnated onto the cellulose fiber non-woven fabric in step S2 is 40 kg.

[0099] The first heating temperature of the drying machine in step S3 is 155°C.

[0100] The second heating temperature of the drying machine in step S3 is 120°C.

[0101] The heating time of the drying machine in step S3 is 65s.

[0102] The temperature of the water in the washing machine in step S4 is 70°C.

[0103] The moisture content of the cellulose fiber nonwoven fabric after drying in step S5 is 3%.

[0104] Example 4

[0105] The specific implementation of Example 4 is the same as that of Example 1, except that:

[0106] The following steps are involved:

[0107] S1: prepare alkaline modifier solution;

[0108] S2: The cellulose fiber nonwoven fabric is automatically unwound, and the solution prepared in the above step S1 is evenly coated on the cellulose fiber nonwoven fabric;

[0109] S3: The cellulose fiber nonwoven fabric obtained in step S2 is sent to a drying machine for heating reaction to perform anion and cation modification;

[0110] S4: The cellulose fiber nonwoven fabric after the heating reaction is sent to a washing machine for rinsing 5 times and neutralized with acid solution;

[0111] S5: drying, slitting, rolling and packaging the washed and neutralized cellulose fiber non-woven fabric.

[0112] The alkaline modifier solution comprises, by mass percentage, 5% ammonium bicarbonate, 8% sodium hydroxide, 4% halogenated carboxylic acid, 8% 2,3-epoxypropyltrimethylammonium chloride, and 75% solvent.

[0113] The halogenated carboxylic acid is monochloroacetic acid.

[0114] The solvent is 50% ethanol aqueous solution.

[0115] In step S2, the cellulose fiber nonwoven fabric is automatically unrolled into the alkaline modifier solution in step S1 and soaked for 3 seconds.

[0116] In the step S2, the machine for uniformly coating the alkaline modifier solution onto the cellulose fiber non-woven fabric is a coating machine.

[0117] The mass of the cellulose fiber nonwoven fabric in step S2 is 30 kg.

[0118] The mass of the alkaline modifier solution applied to the cellulose fiber non-woven fabric in step S2 is 60 kg.

[0119] The first heating temperature of the drying machine in step S3 is 145°C.

[0120] The second heating temperature of the drying machine in step S3 is 90°C.

[0121] The heating time of the drying machine in step S3 is 55 seconds.

[0122] The temperature of the water in the washing machine in step S4 is 90°C.

[0123] The moisture content of the cellulose fiber nonwoven fabric after drying in step S5 is 7%.

[0124] Comparative Example 1

[0125] The specific implementation of Comparative Example 1 is the same as that of Example 1, except that:

[0126] The alkaline modifier solution is 8% sodium hydroxide, 10% monochloroacetic acid, and 82% 50% ethanol aqueous solution by mass percentage.

[0127] Comparative Example 2

[0128] The specific implementation of Comparative Example 2 is the same as that of Example 1, except that:

[0129] The alkaline modifier solution is composed of 8% ammonium bicarbonate, 10% 3-chloro-2-hydroxypropyltrimethylammonium chloride, and 82% 50% ethanol aqueous solution by mass percentage.

[0130] Comparative Example 3

[0131] The specific implementation of Comparative Example 3 is the same as that of Example 1, except that the mass of the cellulose fiber non-woven fabric in step S2 is 20 kg.

[0132] The mass of the alkaline modifier solution impregnated onto the cellulose fiber non-woven fabric in step S2 is 30 kg.

[0133] Comparative Example 4

[0134] The specific implementation of Comparative Example 4 is the same as that of Example 1, except that the first heating temperature of the drying machine in step S3 is 130°C.

[0135] The second heating temperature of the drying machine in step S3 is 130°C.

[0136] The heating time of the drying machine in step S3 is 30 seconds.

[0137] Comparative Example 5

[0138] The specific implementation of Comparative Example 5 is the same as that of Example 1, except that the temperature of the water in the washing machine in step S4 is 50°C.

[0139] Performance Testing

[0140] 1. Compare the cellulose fiber nonwoven fabrics prepared in Examples 1 to 3 and Comparative Examples 1 to 5 with the standard sample and assign scores to the products made under different process conditions. The softest texture is given 10 points, and the hardest texture is given 1 point.

[0141] 2. Soak the cellulose fiber nonwoven fabrics prepared in Examples 1-3 and Comparative Examples 1-5 in water, remove them after they are fully wetted, and test them using a visible light transmittance meter when no water droplets are noticeable. A transmittance of 100% indicates optimal transparency, while lower transmittance values ​​indicate poor transparency.

[0142] 3. According to the FZ / T 64012-2013 standard, the breaking strength, thickness and water absorption of the cellulose fiber nonwoven fabrics prepared in Examples 1 to 3 and Comparative Examples 1 to 5 were measured.

[0143] Table 1

[0144]

Claims

1. A method for preparing anion- and cation-modified cellulose fiber nonwoven fabric, characterized in that: The following steps are involved: S1: prepare alkaline modifier solution; S2: The cellulose fiber nonwoven fabric is unwound automatically, and the solution prepared in the above step S1 is evenly impregnated onto the cellulose fiber nonwoven fabric; S3: The cellulose fiber nonwoven fabric obtained in step S2 is sent to a drying machine for heating reaction to perform anion and cation modification; S4: The cellulose fiber nonwoven fabric after the heating reaction is sent to a washing machine for rinsing 5 times and neutralized with acid solution; S5: drying, slitting, rolling and packaging the washed and neutralized cellulose fiber non-woven fabric; The alkaline modifier solution includes a catalyst, a solvent, sodium hydroxide, and a halogenated carboxylic acid; The catalyst is ammonium bicarbonate; The alkaline modifier solution is composed of 8% ammonium bicarbonate, 8% sodium hydroxide, 10% halogenated carboxylic acid, and 74% solvent by mass percentage; The halogenated carboxylic acid is monochloroacetic acid; The solvent is an ethanol aqueous solution with a mass fraction of 50%; The Tencel fiber content of the cellulose fiber non-woven fabric in step S2 is 100%; In step S2, the cellulose fiber nonwoven fabric is automatically unwound into the alkaline modifier solution in step S1 and soaked for 2 seconds; In the step S2, the machine for uniformly padding the alkaline modifier solution onto the cellulose fiber non-woven fabric is a padder; The mass of the cellulose fiber nonwoven fabric in step S2 is 25 kg; The mass of the alkaline modifier solution impregnated onto the cellulose fiber non-woven fabric in step S2 is 75 kg; The drying machine in step S3 has a double-sided temperature control function; The first heating temperature of the drying machine in step S3 is 150°C; The second heating temperature of the drying machine in step S3 is 80° C.; and a product with different degrees of modification on the front and back surfaces is obtained; The heating time of the drying machine in step S3 is 60s; The temperature of the water in the washing machine in step S4 is 80°C; The acid is citric acid; The citric acid is a 10% citric acid aqueous solution; The moisture content of the cellulose fiber nonwoven fabric after drying in step S5 is 5%.

2. A method for preparing anion- and cation-modified cellulose fiber nonwoven fabric, characterized in that: The following steps are involved: S1: prepare alkaline modifier solution; S2: The cellulose fiber nonwoven fabric is unwound automatically, and the solution prepared in the above step S1 is evenly impregnated onto the cellulose fiber nonwoven fabric; S3: The cellulose fiber nonwoven fabric obtained in step S2 is sent to a drying machine for heating reaction to perform anion and cation modification; S4: The cellulose fiber nonwoven fabric after the heating reaction is sent to a washing machine for rinsing 5 times and neutralized with acid solution; S5: drying, slitting, rolling and packaging the washed and neutralized cellulose fiber non-woven fabric; The alkaline modifier solution is composed of 5% ammonium bicarbonate, 11% sodium hydroxide, 8% 3-chloro-2-hydroxypropyltrimethylammonium chloride, and 76% solvent by mass percentage; The solvent is an ethanol aqueous solution with a mass fraction of 50%; In step S2, the cellulose fiber nonwoven fabric is automatically unwound into the alkaline modifier solution in step S1 and soaked for 3 seconds; In the step S2, the machine for uniformly padding the alkaline modifier solution onto the cellulose fiber non-woven fabric is a padder; The mass of the cellulose fiber nonwoven fabric in step S2 is 40 kg; The mass of the alkaline modifier solution impregnated onto the cellulose fiber non-woven fabric in step S2 is 80 kg; The first heating temperature of the drying machine in step S3 is 145°C; The second heating temperature of the drying machine in step S3 is 100° C.; and a product with different degrees of modification on the front and back surfaces is obtained; The heating time of the drying machine in step S3 is 55s; The temperature of the water in the washing machine in step S4 is 90°C; The moisture content of the cellulose fiber nonwoven fabric after drying in step S5 is 7%.

3. A method for preparing anion- and cation-modified cellulose fiber nonwoven fabric, characterized in that: The following steps are involved: S1: prepare alkaline modifier solution; S2: The cellulose fiber nonwoven fabric is unwound automatically, and the solution prepared in the above step S1 is evenly impregnated onto the cellulose fiber nonwoven fabric; S3: The cellulose fiber nonwoven fabric obtained in step S2 is sent to a drying machine for heating reaction to perform anion and cation modification; S4: The cellulose fiber nonwoven fabric after the heating reaction is sent to a washing machine for rinsing 5 times and neutralized with acid solution; S5: drying, slitting, rolling and packaging the washed and neutralized cellulose fiber non-woven fabric; The alkaline modifier solution is composed of 10% ammonium bicarbonate, 7% sodium hydroxide, 4% halogenated carboxylic acid, 8% 2,3-epoxypropyltrimethylammonium chloride, and 71% solvent by mass percentage; The halogenated carboxylic acid is monochloroacetic acid; The solvent is clean water; In step S2, the cellulose fiber nonwoven fabric is automatically unwound into the alkaline modifier solution in step S1 and soaked for 1 second; The mass of the cellulose fiber nonwoven fabric in step S2 is 10 kg; The mass of the alkaline modifier solution impregnated onto the cellulose fiber nonwoven fabric in step S2 is 40 kg; The first heating temperature of the drying machine in step S3 is 155°C; The second heating temperature of the drying machine in step S3 is 120° C.; and a product with different degrees of modification on the front and back surfaces is obtained; The heating time of the drying machine in step S3 is 65s; The temperature of the water in the washing machine in step S4 is 70°C; The moisture content of the cellulose fiber nonwoven fabric after drying in step S5 is 3%.

4. A cellulose fiber nonwoven fabric obtained by the method for preparing anion- and cation-modified cellulose fiber nonwoven fabric according to any one of claims 1 to 3.

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