Preparation method of cross-linked cellulose fiber

Abstract

The invention discloses a preparation method of cross-linked cellulose fibers, and belongs to the technical field of cellulose preparation. The method comprises the following steps that a cross-linking agent solution and a catalyst solution are added to Lyocell fibers, preliminary curing is conducted under the first set temperature condition, the preliminarily cured Lyocell fibers are obtained, in the cross-linking agent solution, the mass percentage content of a cross-linking agent solute ranges from 0.1% to 10%, and the mass percentage content is defined as a; in the catalyst solution, the value range of the mass percentage content of a catalyst solute is (0-5%) * a; under the condition of a second set temperature, washing the cured Lyocell fiber, changing the electron cloud density distribution of the cured Lyocell fiber, and completing deep curing to obtain the deeply cured Lyocell fiber; and carrying out post-treatment on the deeply cured Lyocell fiber, so as to obtain the cross-linked cellulose fiber. The cross-linking limiting device can improve the uniformity of cross-linking limiting and the product quality.

Description

Technical Field

[0001] The invention relates to the technical field of cellulose preparation, and in particular to a method for preparing cross-linked cellulose fibers. Background Art

[0002] The cellulose material prepared by the NMMO solvent method avoids the shortcomings of natural cellulose materials, such as single product, single performance, and great environmental impact; at the same time, it can reduce the large amount of acidic and alkaline substances required in the production process of traditional cellulose materials, get rid of the pollution problems caused by the production process of traditional cellulose materials; and can expand the application field of cellulose materials. It has the two major advantages of "sustainable development" and "environmental protection" and is a "green material" in the true sense. It has a very broad prospect. However, fabrics produced by conventional Lyocell fibers will pill after a period of use. At the same time, there are problems such as uneven dyeing, frosty appearance of fabrics, inconsistent appearance, and yarn hairiness, neps and broken ends in the spinning process. Summary of the invention

[0003] In view of this, the present invention provides a method for preparing cross-linked cellulose fibers, which can improve the uniformity of cross-linking limitation and product quality, thereby being more suitable for practical use.

[0004] In order to achieve the above object, the technical scheme of the preparation method of cross-linked cellulose fibers provided by the present invention is as follows:

[0005] The preparation method of the cross-linked cellulose fiber provided by the present invention comprises the following steps:

[0006] Adding a crosslinking agent solution and a catalyst solution to the Lyocell fiber, and preliminarily curing the Lyocell fiber under a first set temperature condition to obtain a preliminarily cured Lyocell fiber, wherein the mass percentage content of the crosslinking agent solute in the crosslinking agent solution is in the range of 0.1%-10%, defined as a; and the mass percentage content of the catalyst solute in the catalyst solution is in the range of (0-5%)×a;

[0007] Washing the cured Lyocell fiber to change the electron cloud density distribution of the cured Lyocell fiber, completing deep curing to obtain a deeply cured Lyocell fiber;

[0008] The deeply cured Lyocell fibers are post-treated to obtain cross-linked cellulose fibers.

[0009] The method for preparing the cross-linked cellulose fibers provided by the present invention can also be further implemented by adopting the following technical measures.

[0010] Preferably, in the step of washing the cured Lyocell fiber, changing the electron cloud density distribution of the cured Lyocell fiber, completing deep curing, and obtaining the deeply cured Lyocell fiber, the temperature of the solution for washing the cured Lyocell fiber is T=5×pH+300±12°C, wherein T is Kelvin temperature and pH is the pH of the solution for washing the cured Lyocell fiber.

[0011] Preferably, in the step of washing the cured Lyocell fiber, changing the electron cloud density distribution of the cured Lyocell fiber, completing deep curing, and obtaining the deeply cured Lyocell fiber, the solution for washing the cured Lyocell fiber includes two or more acid-base solutions with different gradients, wherein:

[0012] The pH value range of the second gradient acid-base solution is 3-8;

[0013] The pH value range of the third gradient acid-base solution is 6-13.

[0014] Preferably, in the step of washing the cured Lyocell fiber, changing the electron cloud density distribution of the cured Lyocell fiber, completing deep curing, and obtaining the deeply cured Lyocell fiber, the solution for washing the cured Lyocell fiber further includes a first gradient acid-base solution, wherein:

[0015] The pH value range of the first gradient acid-base solution is 4-14.

[0016] Preferably, the method of adding the crosslinking agent solution or the catalyst solution to the Lyocell fiber comprises one method selected from the group consisting of soaking, padding, and spraying, or a combination of the methods.

[0017] Preferably, the first set temperature is in the range of 20-95° C., based on the reaction of the cross-linking agent.

[0018] Preferably, during the step of adding the crosslinking agent solution and the catalyst solution to the Lyocell fibers, the treatment method specifically includes one or more of the following: tow crosslinking, carpet crosslinking, finished fiber crosslinking, fiber yarn crosslinking and fiber fabric crosslinking.

[0019] Preferably, in the step of adding a crosslinking agent solution and a catalyst solution to the Lyocell fiber and preliminarily curing the Lyocell fiber at a first set temperature to obtain preliminarily cured Lyocell fiber,

[0020] If a cross-linking reaction is performed before cutting, the specific method of the preliminary curing includes infrared heating, hot roller heating, microwave heating, radio frequency heating, steam heating, or a combination of the two;

[0021] If heating is performed after cutting, the specific method of the preliminary curing includes infrared heating, microwave heating, radio frequency heating, steam heating, drying heating or a combination of the two.

[0022] Preferably, the crosslinker solution is selected from one or a mixed solution of difluoromonochloropyrimidine, dichloropyrimidine, dichloroquinoxaline pyrimidine, dichloropyridines, dichloropyridazines, trichloropyridazines, difluoromonochloropyridazines, bis-chloro-s-triazine, dichloro-s-triazine, dichlorotriazines, and dichlorophthalazines.

[0023] Preferably, the catalyst solute is selected from one or more of aminobenzenesulfonic acid, aminobenzoic acid, aromatic amino, sulfonic acid and phenol.

[0024] Preferably, the substances added to the cross-linking agent solution include the first one or more of alkaline substances, surfactants and salts.

[0025] Preferably, the substances added to the catalyst solution include the first one or more of alkaline substances, surfactants and salts.

[0026] Preferably, the alkaline substance includes one or more of urea, sodium bicarbonate, sodium carbonate, sodium hydroxide, ammonia, sodium phosphate, sodium hypophosphite, potassium hydroxide, sodium acetate, and boric acid, and the pH value range of the alkaline substance is 8-14.

[0027] Preferably, the surfactant includes one or more of penetrant T, Abega B, polyoxyethylene condensate, naphthalenesulfonic acid formaldehyde condensate, fatty amides, sodium dodecyl sulfate, monolauryl phosphate, and potassium dodecyl phosphate, and the added amount of the surfactant is 0-5% of the mass of the crosslinker solute in the crosslinker solution.

[0028] Preferably, the salts include one or more of magnesium chloride, sodium chloride, sodium sulfate, potassium sulfate, and potassium chloride, and the mass percentage of the salts in the cross-linking agent solution is in the range of 0-10%.

[0029] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0030] The present invention controls the temperature so that the crosslinking agent is evenly distributed on the fiber without chemical reaction between the crosslinking agent and the catalyst, which is beneficial to improving the final crosslinking uniformity;

[0031] The present invention adds chemical additives, such as a crosslinking agent or a catalyst, to the water washing liquid, so that the crosslinking agent and the catalyst are fully and evenly distributed on the fiber before reacting with the fiber, thereby fundamentally solving the problem of uneven crosslinking of the fiber.

[0032] The present invention proposes a step-by-step curing process, which specifically includes preliminary curing and gradient in-depth curing. After part of the crosslinking agent is reacted on the fiber, the influence of the steric hindrance of the crosslinking agent and the overall electron cloud density of cellulose on the in-depth curing is reduced, thereby ensuring that the crosslinking agent is fully utilized during the in-depth curing and reducing the influence on the uniformity of the crosslinked fiber and the product quality.

[0033] The deep curing process proposed by the present invention has significant energy-saving advantages, and the flushing allows the second active group of the cross-linking agent to react completely, thus avoiding the problem of uneven acid and alkali solutions during the deep curing process;

[0034] The present invention utilizes the pH value of the first gradient acid-base solution to promote the crosslinking agent to start a complete reaction, which helps to evenly distribute the electron cloud of the fiber as a whole and improve the final crosslinking uniformity;

[0035] The present invention uses the second gradient acid-base solution to further change the electron cloud distribution on the fiber, reduce the charge resistance, and provide a sufficient environment for the remaining unreacted groups in the second step curing reaction; promote the crosslinking agent on the fiber to further undergo the second step curing reaction, and ensure uniformity and crosslinking effect;

[0036] The present invention utilizes the third gradient acid-base solution to wash the fiber, thereby changing the overall electron cloud density of the fiber again, reducing the charge resistance of the chemical reaction, and helping to stabilize the fiber performance for a long time.

[0037] The invention provides a new method for preparing cross-linked Lyocell fibers, which overcomes the shortcomings of the prior art and has the advantages of good uniformity, long storage time, low production energy consumption, small footprint, etc. DETAILED DESCRIPTION

[0038] In view of this, the present invention provides a method for preparing cross-linked cellulose fibers, which can improve the uniformity of cross-linking limitation and product quality, thereby being more suitable for practical use.

[0039] After arduous efforts, the inventor discovered that

[0040] The production of cellulose materials by NMMO solvent method is a new process for producing cellulose materials without chemical reaction. The process mainly dissolves cellulose pulp in NMMO aqueous solution to obtain viscous spinning solution, and then obtains cellulose materials by dry-jet wet spinning process. At the same time, NMMO precipitated in the coagulation bath is recycled and reused, with a recovery rate of up to 99.8%. The entire production system is closed-loop, with no waste discharge and no pollution to the environment. The spinning solution prepared by dissolving cellulose in NMMO aqueous solution is extruded from the spinneret, and after a period of air bath, the filaments are rapidly cooled and initially formed, and then enter the coagulation bath. The filaments enter the coagulation bath for bidirectional diffusion to form primary fibers; in the process of Lyocell fiber dry-jet wet spinning, the fiber crystal units are highly oriented in a densely packed manner in the air gap stage, and have strong bonding force in the longitudinal direction. Therefore, Lyocell has a highly oriented and highly crystalline structure. But at the same time, it will cause the lateral force of the fiber crystal unit to weaken. Under wet conditions, microfibrils are very easy to peel off from the fiber under external action, causing fibrillation on the fiber surface. Fabrics produced using conventional Lyocell fibers will develop pilling after a period of use. There are also problems such as uneven dyeing, frosty appearance of the fabric, inconsistent appearance, and yarn hairiness, neps and broken ends during the spinning process. These phenomena are all caused by the easy fibrillation of Lyocell fibers.

[0041] It is worth noting that the chemical bonds formed by using cross-linking agents to prepare cross-linked fibers are extremely unstable in some cases. Overly acidic, overly alkaline, high temperature and high pressure environments can lead to instability of the cross-linked bonds.

[0042] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description of a method for preparing a cross-linked cellulose fiber according to the present invention, its specific implementation, structure, characteristics and effects in combination with the preferred embodiments. In the following description, different "one embodiment" or "embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures, or characteristics in one or more embodiments may be combined in any suitable form.

[0043] The term "and / or" in this article is merely a description of the association relationship of associated objects, indicating that three relationships may exist, for example, A and / or B. Specifically, it is understood that: A and B may be included at the same time, A may exist alone, or B may exist alone, and any of the above three situations may be met.

[0044] The preparation method of the cross-linked cellulose fiber provided by the present invention comprises the following steps:

[0045] Step S1: Add a crosslinking agent solution and a catalyst solution to the Lyocell fiber, and preliminarily cure it under a first set temperature condition to obtain a preliminarily cured Lyocell fiber, wherein in the crosslinking agent solution, the mass percentage of the crosslinking agent solute ranges from 0.1% to 10%, defined as a; in the catalyst solution, the mass percentage of the catalyst solute ranges from (0-5%) × a. The crosslinking agent is the root of the fiber's resistance to fibrillation. Too high a concentration will lead to a significant increase in cost and make commercial production impossible. Too low a concentration will lead to insufficient activity and make it impossible to produce crosslinked fiber products that meet the requirements.

[0046] After the crosslinking agent or catalyst is added to the fiber, it is necessary to maintain a low bath ratio, which is conducive to reducing the energy consumption of the initial curing and in-depth curing process; and the active group has a high concentration under the condition of low bath ratio, which will further increase the activity of the crosslinking agent and the hydroxyl group on the cellulose, and help to improve the final crosslinking effect. In the above scheme, the method of treating the fiber with a low-temperature crosslinking agent solution and a catalyst solution specifically includes tow crosslinking, silk carpet crosslinking, finished fiber crosslinking, fiber yarn crosslinking and fiber fabric crosslinking. That is, before, after and during the cutting of the Lyocell fiber in the formed fiber production chain, even the finished fabric can be treated with a chemical reagent solution. Specifically, in the nascent Lyocell fiber, there is still a large amount of NMMO solution that needs to be recycled and used. The recycling method is to use water to rinse the fiber and recover the NMMO in the water. Therefore, the catalyst or crosslinking agent addition method at different stages of fiber production has the best economic choice. A cellulose crosslinking agent is a chemical substance that contains at least two or more active groups that can react with cellulose fibers; when some of the chemical bonds of the crosslinking agent react, the electron cloud density of the cellulose will change the electron cloud density of the remaining unreacted crosslinking agent and the active groups, ultimately affecting the reactivity of the remaining crosslinking agent and the active groups. Changing the reaction conditions of the remaining reactions can lead to better crosslinking effects, which is specifically reflected in changes in reaction temperature, reaction rate, reaction pressure or reaction pH. Therefore, no matter what kind of crosslinking agent is used, its reaction with cellulose should be controlled under different conditions so that it reacts in steps;

[0047] The first stage curing reaction temperature range is 20-95°C, and the heating time is 10s-30min.

[0048] Furthermore, the initial curing temperature should be based on the partial reaction of the crosslinking agent; for example, when difluorochloropyrimidine is used as the crosslinking agent, the optimal curing temperature is 30-40°C; when dichloropyrimidine is used as the crosslinking agent, the optimal initial curing temperature is 40-60°C; when dichlorotriazine is used as the crosslinking agent, the optimal reaction temperature is 30-70°C.

[0049] Therefore, the present invention washes the obtained preliminary solidified fiber with a gradient acid-base solution to allow the preliminary solidified fiber to further react in the gradient acid-base solution.

[0050] The deep curing reaction can use an acidic or alkaline solution to rinse the above fibers, which is economically advantageous; while using two or more acidic or alkaline solutions to rinse the fibers will increase production costs, but will improve product quality; the specific preparation of the fibers needs to be based on production requirements.

[0051] Step S2: washing the cured Lyocell fiber to change the electron cloud density distribution of the cured Lyocell fiber, completing deep curing to obtain a deeply cured Lyocell fiber;

[0052] Step S3: performing post-treatment on the deeply cured Lyocell fibers to obtain cross-linked cellulose fibers.

[0053] Among them, in the process of washing the cured Lyocell fiber, changing the electron cloud density distribution of the cured Lyocell fiber, completing deep curing, and obtaining the deeply cured Lyocell fiber, the temperature of the solution of the washed and cured Lyocell fiber is T=5×pH+300±12°C, wherein T is Kelvin temperature, and pH is the pH of the solution of the washed and cured Lyocell fiber.

[0054] In the process of washing the solidified Lyocell fiber, changing the electron cloud density distribution of the solidified Lyocell fiber, completing deep curing, and obtaining the deeply cured Lyocell fiber, the solution for washing the solidified Lyocell fiber includes three acid-base solutions with different gradients, wherein:

[0055] The pH value range of the first gradient acid-base solution is 4-14;

[0056] The pH value range of the second gradient acid-base solution is 3-8;

[0057] The pH value range of the third gradient acid-base solution is 6-13.

[0058] In the step of washing the solidified Lyocell fiber, changing the electron cloud density distribution of the solidified Lyocell fiber, completing deep curing, and obtaining the deeply cured Lyocell fiber, the solution for washing the solidified Lyocell fiber also includes a first gradient acid-base solution, wherein:

[0059] The pH value range of the first gradient acid-base solution is 4-14.

[0060] The method of adding the crosslinking agent solution or the catalyst solution to the Lyocell fiber includes one method of soaking, padding, and spraying, or a combination of several methods.

[0061] The first set temperature is in the range of 20-95° C., based on the reaction of the cross-linking agent.

[0062] Among them, during the step of adding the crosslinking agent solution and the catalyst solution to the Lyocell fiber, the treatment method specifically includes one or more of the following: tow crosslinking, carpet crosslinking, finished fiber crosslinking, fiber yarn crosslinking and fiber fabric crosslinking.

[0063] In the step of adding a crosslinking agent solution and a catalyst solution to the Lyocell fiber and preliminarily curing the Lyocell fiber at a first set temperature to obtain the preliminarily cured Lyocell fiber,

[0064] If a cross-linking reaction is carried out before cutting, the specific method of preliminary curing includes one or a combination of infrared heating, hot roller heating, microwave heating, radio frequency heating, and steam heating;

[0065] If heating is performed after cutting, the specific method of preliminary curing includes infrared heating, microwave heating, radio frequency heating, steam heating, drying heating or a combination of the two.

[0066] Among them, the crosslinking agent solution is selected from one or a mixed solution of difluoromonochloropyrimidine, dichloropyrimidine, dichloroquinoxaline pyrimidine, dichloropyridines, dichloropyridazines, trichloropyridazines, difluoromonochloropyridazines, bis-chloro-s-triazine, dichloro-s-triazine, dichlorotriazines, and dichlorophthalazines.

[0067] Wherein, the catalyst solute is selected from one or more of aminobenzenesulfonic acid, aminobenzoic acid, aromatic amino, sulfonic acid and phenol.

[0068] The substances added to the catalyst solution include the first one or more of alkaline substances, surfactants and salts.

[0069] The substances added to the cross-linking agent solution include the first one or more of alkaline substances, surfactants and salts.

[0070] Among them, the alkaline substances include one or more of urea, sodium bicarbonate, sodium carbonate, sodium hydroxide, ammonia, sodium phosphate, sodium hypophosphite, potassium hydroxide, sodium acetate, and boric acid, and the pH value of the alkaline substances ranges from 8 to 14. The alkaline substances can provide a dissolving environment and a stable environment for the cross-linking agent, which is helpful for the dissolution of the cross-linking agent. Some cross-linking agents are extremely difficult to dissolve and can only be dissolved in an alkaline environment; the alkaline substances include urea, sodium bicarbonate, sodium carbonate, sodium hydroxide, ammonia, sodium phosphate, sodium hypophosphite, potassium hydroxide, sodium acetate, boric acid, etc.; including but not limited to the above-mentioned auxiliary agents alone or in combination of multiple auxiliary agents.

[0071] The surfactant includes one or more of penetrant T, Abega B, polyoxyethylene condensate, naphthalenesulfonic acid formaldehyde condensate, fatty amides, sodium dodecyl sulfate, monolauryl phosphate, and potassium dodecyl phosphate, and the amount of surfactant added is 0-5% of the mass of the crosslinking agent solute in the crosslinking agent solution. Adding the surfactant is conducive to its uniform distribution inside and outside the fiber, reducing the resistance of the crosslinking agent to penetrate into the fiber; and increasing the solution permeability, which is conducive to significantly improving the uniformity.

[0072] The salts include one or more of magnesium chloride, sodium chloride, sodium sulfate, potassium sulfate, and potassium chloride, and the mass percentage of the salts in the crosslinking agent solution is in the range of 0-10%. The chemical reaction between the cellulose on the cellulose fiber and the crosslinking agent is a reaction between ionized cellulose and the crosslinking agent. Adding salt substances helps ionization of cellulose, reduces the charge resistance between cellulose and various chemical reagents, and increases the final reaction activity. In this process, adding salt substances to the crosslinking agent helps the crosslinking reaction to occur.

[0073] in:

[0074] Fiber wet friction test: FZ / T52019-2018, tested using the lyocell staple fiber industry standard;

[0075] Formaldehyde content test: GB / T2912.1-2009, tested using the national standard for textiles.

[0076] The “fiber wet friction test” is used to indicate the degree of fiber resistance to fibrillation. The higher the degree of fiber resistance to fibrillation, the higher the “wet friction resistance value”.

[0077] In the fiber wet friction test: the final effect is represented by the mean value; the coefficient of variation of the wet friction value is used to represent the crosslinking unevenness; the wet friction times greater than 100 times are defined as having a crosslinking effect, and the crosslinking rate is defined as the ratio of fibers with a crosslinking effect to the total fibers;

[0078] The rate of change of the wet friction value of the fiber (S value) (unit: times / day) is defined as its stability.

[0079] (Among them: S value ≤ 2, excellent; 2<S value ≤ 5, good; 5<S value ≤ 9, medium; S value>9, poor)

[0080] Example 1

[0081] The Lyocell fibers in the tow process are cross-linked using the patented method:

[0082] (1) adding a crosslinking agent solution to the spun fibers by spraying, and then rolling them dry (the moisture content is controlled at 70%), and then adding a catalyst solution by spraying for treatment;

[0083] (2) preliminarily curing the fibers by a mixed heating method of microwave heating and steam heating;

[0084] (3) finally, the fibers are rinsed with a gradient acid-base solution, and then opened and the like are performed to obtain cross-linked fibers.

[0085] The process formula and control conditions are shown in Table 1:

[0086] Table 1 Process formula and control conditions of Example 1

[0087]

[0088] Note: T1 = 5 × 12 + 300 = 360K = 87°C

[0089] Note: T2 = 5 × 2 + 300 = 310K = 37°C

[0090] Note: T3 = 5 × 9 + 300 = 360K = 72°C

[0091] Comparative Example 1

[0092] (1) adding a crosslinking agent solution to the spun fibers by spraying, and then rolling them dry (the moisture content is controlled at 70%), and then adding a catalyst solution by spraying for treatment;

[0093] (2) The fibers are cured by a mixed heating method of microwave heating and steam heating.

[0094] The process formula and control conditions are as follows:

[0095] Table 2 Process formula and control conditions of comparative example 1

[0096]

[0097]

[0098] As shown in Table 3, the performance comparison of the fibers produced in Example 1 and Comparative Example 1 is shown:

[0099] Table 3 Comparison of the properties of the fibers produced in Example 1 and Comparative Example 1

[0100]

[0101] Conclusion: By comparing the fiber properties of Example 1 and Comparative Example 1, it can be seen that the mechanical properties of the cross-linked fiber prepared by the process provided by this patent have no significant difference from those of Comparative Example 1; the cross-linked fiber produced by this patent has significant improvements in cross-linking effect, cross-linking uniformity and cross-linking rate, especially the cross-linking uniformity has been greatly improved; and the unexpected advantage of the cross-linked fiber produced by this patent is its excellent stability, with an S value of only 1. In this way, the cross-linked fiber production process provided by this patent greatly solves the problem of downstream application and provides full guarantee for the stability of product quality; in addition, it also effectively avoids problems such as uneven dyeing in the downstream process.

[0102] Example 2: Cross-linked fibers were produced according to the method shown in Example 1, and the process formula was shown in Table 4. Comparative Example 2-4: Cross-linked fibers were produced according to the method shown in Comparative Example 1, and the process formula was shown in Table 4.

[0103] Table 4 Comparative Example Process Formula and Process Control 2

[0104]

[0105] Table 5 Comparative Example Crosslinking Effect Comparison 1

[0106]

[0107] From Table 5, we can see that:

[0108] It can be seen from Example 2 and Comparative Example 2 that without using a catalyst, the fiber cross-linking effect is significantly reduced, which is caused by the catalytic reaction process of the catalyst;

[0109] It can be seen from Example 2 and Comparative Examples 3 and 4 that the cross-linking effect is significantly reduced after reducing the salt substance or the surfactant.

[0110] Example 3

[0111] The Lyocell fibers cut and laid into a carpet are cross-linked using the method of this patent. The process control is shown in Table 6:

[0112] (1) adding a crosslinking agent solution in the water cutting step, then laying the cut short fibers into a silk blanket and placing it on a conveyor belt, and after rolling dry (the moisture content is controlled at 70%), adding a catalyst solution by spraying for treatment;

[0113] (2) preliminarily curing the fibers by a mixed heating method of microwave heating and steam heating;

[0114] (3) finally, the fibers are rinsed with a gradient acid-base solution, and then opened and the like are performed to obtain cross-linked fibers.

[0115] The process formula and control conditions are shown in Table 1:

[0116] Comparative Examples 5-6 Cross-linked fibers were produced according to the method described in Example 3, and the process control was shown in Table 6:

[0117] Table 6 Comparative Example Process Formula and Process Control 3

[0118] Crosslinking agent process control Catalyst process control Initial curing process Example 3 10℃,1min 10℃,1min 55℃,3min Comparative Example 5 30℃,1min 30℃,1min 55℃,3min Comparative Example 6 10℃,3min 10℃,3min 70℃,3min

[0119] Table 7 Comparative Example Crosslinking Effect Comparison 2

[0120]

[0121] From Table 6 and Table 7, we can see that:

[0122] By comparing Example 3 and Comparative Example 5, it can be seen that, while other processes remain unchanged, the comparative example increases the temperature of the crosslinking agent and the catalyst. Although it has no significant effect on the final crosslinking wet friction resistance average, the crosslinking unevenness rate is significantly increased after the temperature is increased. This is because the crosslinking agent does not undergo chemical reaction at low temperatures and is easy to be evenly distributed on the fiber; while at high temperatures, the cellulose hydroxyl group will react with the crosslinking agent, resulting in solidification before it is evenly distributed, affecting the uniform distribution of the crosslinking agent on the fiber; therefore, after the temperature is increased, the fiber uniformity will be significantly reduced;

[0123] By comparing Example 3 and Comparative Example 6, it can be seen that increasing the temperature of the initial curing process will reduce the cross-linking effect. This is because excessively high temperature will cause the cross-linking agent to react with the fiber to form steric hindrance, making it difficult for the remaining cross-linking agent to undergo a cross-linking reaction, ultimately resulting in a significant decrease in the cross-linking effect. In contrast, Example 3 gradually increases the temperature and gently controls the entire reaction process, allowing the cross-linking agent to react gradually, and ultimately the cross-linking effect is significantly improved.

[0124] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0125] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for preparing cross-linked cellulose fibers, characterized in that: The following steps are involved: Adding a crosslinking agent solution and a catalyst solution to the Lyocell fiber, and preliminarily curing the Lyocell fiber under a first set temperature condition to obtain a preliminarily cured Lyocell fiber, wherein the mass percentage content of the crosslinking agent solute in the crosslinking agent solution is in the range of 0.1%-10%, defined as a; and the mass percentage content of the catalyst solute in the catalyst solution is in the range of (0-5%)×a; Washing the cured Lyocell fiber to change the electron cloud density distribution of the cured Lyocell fiber; and completing deep curing to obtain a deeply cured Lyocell fiber; The deeply cured Lyocell fibers are post-treated to obtain cross-linked cellulose fibers.

2. The method for preparing cross-linked cellulose fibers according to claim 1, characterized in that: During the step of washing the cured Lyocell fiber, changing the electron cloud density distribution of the cured Lyocell fiber, completing deep curing, and obtaining the deeply cured Lyocell fiber, the temperature of the solution for washing the cured Lyocell fiber is T=5×pH+300±12°C, wherein T is Kelvin temperature and pH is the pH of the solution for washing the cured Lyocell fiber.

3. The method for preparing cross-linked cellulose fibers according to claim 1, characterized in that: In the step of washing the cured Lyocell fiber, changing the electron cloud density distribution of the cured Lyocell fiber, completing deep curing, and obtaining the deeply cured Lyocell fiber, the solution for washing the cured Lyocell fiber includes two or more acid-base solutions with different gradients, wherein: The pH value range of the second gradient acid-base solution is 3-8; The pH value range of the third gradient acid-base solution is 6-13.

4. The method for preparing cross-linked cellulose fibers according to claim 3, characterized in that: In the step of washing the cured Lyocell fiber, changing the electron cloud density distribution of the cured Lyocell fiber, completing deep curing, and obtaining the deeply cured Lyocell fiber, the solution for washing the cured Lyocell fiber also includes a first gradient acid-base solution, wherein: The pH value range of the first gradient acid-base solution is 4-14.

5. The method for preparing cross-linked cellulose fibers according to claim 1, characterized in that: The method of adding the crosslinking agent solution or the catalyst solution to the Lyocell fiber includes one method of soaking, padding, and spraying, or a combination of several methods.

6. The method for preparing cross-linked cellulose fibers according to claim 1, characterized in that: The first set temperature has a value range of 20-95° C., based on the reaction of the cross-linking agent.

7. The method for preparing cross-linked cellulose fibers according to claim 1, characterized in that: During the step of adding the crosslinking agent solution and the catalyst solution to the Lyocell fibers, the treatment method specifically includes one or more of the following: tow crosslinking, carpet crosslinking, finished fiber crosslinking, fiber yarn crosslinking and fiber fabric crosslinking.

8. The method for preparing cross-linked cellulose fibers according to claim 1, characterized in that: In the step of adding a crosslinking agent solution and a catalyst solution to the Lyocell fiber and preliminarily curing the Lyocell fiber at a first set temperature to obtain preliminarily cured Lyocell fiber, If a cross-linking reaction is performed before cutting, the specific method of the preliminary curing includes infrared heating, hot roller heating, microwave heating, radio frequency heating, steam heating, or a combination of the two; If heating is performed after cutting, the specific method of the preliminary curing includes infrared heating, microwave heating, radio frequency heating, steam heating, drying heating or a combination of the two.

9. The method for preparing cross-linked cellulose fibers according to claim 1, characterized in that: The crosslinking agent solution is selected from one or a mixed solution of difluoromonochloropyrimidine, dichloropyrimidine, dichloroquinoxaline pyrimidine, dichloropyridines, dichloropyridazines, trichloropyridazines, difluoromonochloropyridazines, bis-chloro-s-triazine, dichloro-s-triazine, dichlorotriazines, and dichlorophthalazines.

10. The method for preparing cross-linked cellulose fibers according to claim 1, characterized in that: The catalyst solute is selected from one or more of aminobenzenesulfonic acid, aminobenzoic acid, aromatic amino, sulfonic acid, and phenol; Preferably, the substance added to the cross-linking agent solution includes the first one or more of alkaline substances, surfactants, and salts; Preferably, the substances further added to the catalyst solution include the first one or more of alkaline substances, surfactants, and salts; Preferably, the alkaline substance includes one or more of urea, sodium bicarbonate, sodium carbonate, sodium hydroxide, ammonia, sodium phosphate, sodium hypophosphite, potassium hydroxide, sodium acetate, and boric acid, and the pH value of the alkaline substance ranges from 8 to 14; Preferably, the surfactant comprises one or more of penetrant T, Abega B, polyoxyethylene condensate, naphthalenesulfonic acid formaldehyde condensate, fatty amides, sodium dodecyl sulfate, monolauryl phosphate, and potassium dodecyl phosphate, and the added amount of the surfactant is 0-5% of the mass of the crosslinker solute in the crosslinker solution; Preferably, the salts include one or more of magnesium chloride, sodium chloride, sodium sulfate, potassium sulfate, and potassium chloride, and the mass percentage of the salts in the cross-linking agent solution is in the range of 0-10%.

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