Process for the preparation of crosslinked cellulose fibers

Abstract

The application discloses a preparation method of cross-linked cellulose fiber and belongs to the technical field of cellulose preparation. The method comprises the following steps: adding a cross-linking agent solution and a catalyst solution to Lyocell fiber, and preliminarily solidifying at a first set temperature to obtain preliminarily solidified Lyocell fiber, wherein the mass percentage of the cross-linking agent solute in the cross-linking agent solution is 0.1% to 10%, defined as a; the mass percentage of the catalyst solute in the catalyst solution is (0-5%)x a; the solidified Lyocell fiber is washed at a second set temperature to change the electron cloud density distribution of the solidified Lyocell fiber, deep solidification is completed, and deep solidified Lyocell fiber is obtained; and the deep solidified Lyocell fiber is subjected to post-treatment to obtain cross-linked cellulose fiber. The method can improve the uniformity of cross-linking and the product quality.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cellulose preparation, in particular to a preparation method of cross-linked cellulose fiber. BACKGROUND

[0002] The cellulose material prepared by the NMMO solvent method avoids the shortcomings of single product and single performance of natural cellulose material, and is less affected by the environment. Meanwhile, the method can reduce the large amount of acid and alkali substances required in the traditional cellulose material production process, and eliminate the pollution problems caused by the traditional cellulose material production process. In addition, the method can expand the application field of cellulose material. The method has two advantages of "sustainable development" and "environmental protection", and is a truly "green material". The method has a very broad prospect. However, the fabric produced by using conventional Lyocell fiber will have a pilling phenomenon after a period of use, and also has problems of uneven dyeing, frosty appearance of the fabric, inconsistent appearance, and yarn hairiness, neps and broken ends in the spinning process. SUMMARY

[0003] Therefore, the present application provides a preparation method of cross-linked cellulose fiber, which can improve the uniformity of cross-linking and the quality of the product, and is more suitable for practical use.

[0004] In order to achieve the above-mentioned purpose, the technical scheme of the preparation method of cross-linked cellulose fiber provided by the present application is as follows:

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

[0006] The cross-linking agent solution and the catalyst solution are added to the Lyocell fiber, and preliminary solidification is carried out at a first set temperature to obtain the Lyocell fiber after preliminary solidification, wherein the mass percentage content of the cross-linking agent solute in the cross-linking agent solution is 0.1%-10%, defined as a; the mass percentage content of the catalyst solute in the catalyst solution is (0-5%)×a;

[0007] The Lyocell fiber after solidification is washed to change the electron cloud density distribution of the Lyocell fiber after solidification, complete deep solidification, and obtain the Lyocell fiber after deep solidification;

[0008] The Lyocell fiber after deep solidification is subjected to post-treatment to obtain the cross-linked cellulose fiber.

[0009] The preparation method of cross-linked cellulose fiber provided by the present application can further be realized by the following technical measures.

[0010] As preferred, in the step of washing the solidified Lyocell fiber, changing the electron cloud density distribution of the solidified Lyocell fiber, completing deep solidification, and obtaining the deep solidified Lyocell fiber, the solution for washing the solidified Lyocell fiber has a temperature T = 5 x pH + 300 ± 12 ℃, where T is the temperature in Kelvin, and pH is the pH of the solution for washing the solidified Lyocell fiber.

[0011] As preferred, in the step of washing the solidified Lyocell fiber, changing the electron cloud density distribution of the solidified Lyocell fiber, completing deep solidification, and obtaining the deep solidified Lyocell fiber, the solution for washing the solidified Lyocell fiber includes two or more different gradient acid-base solutions, where:

[0012] The pH of the second gradient acid-base solution ranges from 3 to 8.

[0013] The pH of the third gradient acid-base solution ranges from 6 to 13.

[0014] As preferred, in the step of washing the solidified Lyocell fiber, changing the electron cloud density distribution of the solidified Lyocell fiber, completing deep solidification, and obtaining the deep solidified Lyocell fiber, the solution for washing the solidified Lyocell fiber further includes a first gradient acid-base solution, where:

[0015] The pH of the first gradient acid-base solution ranges from 4 to 14.

[0016] As preferred, the method of adding a crosslinking agent solution or a catalyst solution to the Lyocell fiber includes one of immersion, padding, spraying, or a combination of several methods.

[0017] As preferred, the first set temperature ranges from 20 to 95 ℃, based on the reaction of the crosslinking agent.

[0018] As preferred, in the step of adding a crosslinking agent solution and a catalyst solution to the Lyocell fiber, the method of processing specifically includes one or several of tow crosslinking, carpet crosslinking, finished fiber crosslinking, fiber yarn crosslinking, and fiber fabric crosslinking.

[0019] As preferred, in the step of adding a crosslinking agent solution and a catalyst solution to the Lyocell fiber, and preliminarily solidifying at a first set temperature to obtain a preliminarily solidified Lyocell fiber,

[0020] If the cross-linking reaction is carried out before cutting, the specific method of the preliminary curing includes one or several of the following: infrared heating, hot roller heating, microwave heating, radio frequency heating, steam heating, and drying heating.

[0021] If the heating is carried out after cutting, the specific method of the preliminary curing includes one or several of the following: infrared heating, microwave heating, radio frequency heating, steam heating, and drying heating.

[0022] As a preference, the cross-linking agent solution is selected from one or several of the following: difluoro-monochloro pyrimidine, dichloro pyrimidine, dichloro quinoxaline pyrimidine, dichloro pyridine, dichloro pyridazine, trichloro pyridazine, difluoro-monochloro pyridazine, bis-monochloro s-triazine, dichloro s-triazine, dichloro triazine, and dichloro phthalazine.

[0023] As a preference, the catalyst solute is selected from one or several of the following: aminobenzenesulfonic acid, aminobenzoic acid, arylamino, sulfonic acid, and phenol.

[0024] As a preference, the additional substance in the cross-linking agent solution includes one or several of the following: alkaline substance, surfactant, and salt.

[0025] As a preference, the additional substance in the catalyst solution includes one or several of the following: alkaline substance, surfactant, and salt.

[0026] As a preference, the alkaline substance includes one or several of the following: 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.

[0027] As a preference, the surfactant includes one or several of the following: penetrant T, Abegall B, polyoxyethylene condensate, naphthalene sulfonic acid formaldehyde condensate, fatty amide, sodium dodecyl sulfate, monolauryl phosphate, and potassium dodecyl phosphate, and the addition amount of the surfactant is 0-5% of the mass of the cross-linking agent solute in the cross-linking agent solution.

[0028] As a preference, the salt includes one or several of the following: magnesium chloride, sodium chloride, sodium sulfate, potassium sulfate, and potassium chloride, and the mass percentage of the salt in the cross-linking agent solution ranges from 0 to 10%.

[0029] Compared with the prior art, the present application has the following beneficial effects:

[0030] The present application controls the temperature to uniformly distribute the cross-linking agent on the fiber without chemical reaction between the cross-linking agent and the catalyst, which is beneficial to the improvement of the final cross-linking uniformity.

[0031] The present application adds chemical additives, such as cross-linking agent or catalyst, in the water washing solution, so that the cross-linking agent and catalyst are not yet reacted with the fiber, and are evenly distributed on the fiber, fundamentally solving the problem of uneven cross-linking of the fiber.

[0032] The present application proposes a step-by-step curing process, specifically including preliminary curing and gradient deep curing method, when part of the cross-linking agent is reacted on the fiber, the steric hindrance of the cross-linking agent and the overall electron cloud density of cellulose are reduced, and the influence of deep curing is ensured, the cross-linking agent is fully utilized, and the influence on the uniformity of the cross-linked fiber and the product quality is reduced.

[0033] The deep curing process proposed by the present application has significant energy saving advantages, and the washing makes the second active group of the cross-linking agent fully react, avoiding the problem of uneven acid-base solution in the deep curing process;

[0034] The present application uses the first gradient acid-base solution pH value to promote the cross-linking agent to start complete reaction, which helps to improve the overall electron cloud distribution of the fiber and the uniformity of the final cross-linking;

[0035] The present application uses the second gradient acid-base solution to further change the electron cloud distribution on the fiber, reduces the charge resistance, and provides a sufficient environment for the remaining unreacted groups in the second curing reaction; promotes the cross-linking agent on the fiber to further undergo the second curing reaction, and ensures the uniformity and cross-linking effect;

[0036] The present application uses the third gradient acid-base solution to flush the fiber, which changes the overall electron cloud density of the fiber again, reduces the charge resistance of the chemical reaction, and helps to stabilize the performance of the fiber for a long time.

[0037] The present application provides a new preparation method of cross-linked Lyocell fiber, which overcomes the shortcomings of the prior art, has the advantages of good uniformity, long storage time, small production energy consumption, small occupied area, etc. DETAILED DESCRIPTION

[0038] Therefore, the present application provides a preparation method of cross-linked cellulose fiber, which can improve the uniformity of cross-linking and product quality, and is more suitable for practical use.

[0039] The present application provides a preparation method of cross-linked cellulose fiber, which can improve the uniformity of cross-linking and product quality, and is more suitable for practical use.

[0040] The production of cellulose material by NMMO solvent method is a new process for producing cellulose material without chemical reaction. The process mainly dissolves cellulose pulp in NMMO aqueous solution to obtain viscous spinning solution, and then the cellulose material is prepared by dry-jet wet spinning process. At the same time, the NMMO precipitated in the coagulation bath is recycled and reused, and the recovery rate is as high as 99.8%. The whole production system is closed loop, no waste discharge, no pollution to the environment. The spinning solution prepared by dissolving cellulose in NMMO aqueous solution is extruded from the spinneret, and the yarn is rapidly cooled and initially formed in the air bath, and then enters the coagulation bath tank. The yarn enters the coagulation bath for bidirectional diffusion to form the primary fiber; in the process of dry-jet wet spinning of Lyocell fiber, the fiber crystalline unit is arranged in a dense packing manner with high orientation in the air gap stage, and has strong binding force in the longitudinal direction. Therefore, Lyocell has high orientation and high crystalline structure. However, it will also lead to the weakening of the transverse force of the fiber crystalline unit. Under wet conditions, the microfibrils are very easy to peel off from the fiber under external action, causing the fibrillation phenomenon on the surface of the fiber. The fabric produced by using conventional Lyocell fiber will have pilling phenomenon after a period of use, and there are problems of uneven dyeing, frosty appearance of the fabric, inconsistent appearance, and also yarn hairiness, neps and broken ends in the spinning process, which are all caused by the easy fibrillation of Lyocell fiber.

[0041] It is worth noting that the chemical bonds formed by using the crosslinking agent to prepare the crosslinked fiber are extremely unstable in some cases, and the over-acidic, over-alkaline and high temperature and high pressure environments will cause the instability of the crosslinking bond.

[0042] In order to further illustrate the technical means and effects taken by the present application to achieve the predetermined object, the following will be described in detail in combination with the preferred embodiments. The specific implementation, structure, characteristics and effects of the preparation method of the crosslinked cellulose fiber according to the present application are described as follows. In the following description, different "an embodiment" or "embodiments" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0043] The term "and / or" in this paper is only a description of the association relationship of the associated objects, which means that there can be three kinds of relationships, for example, A and / or B, which can be understood as: A and B can exist at the same time, A can exist alone, and B can exist alone, and any one of the above three cases can exist.

[0044] The preparation method of the crosslinked cellulose fiber provided by the present application comprises the following steps:

[0045] Step S1: adding a crosslinking agent solution and a catalyst solution to the Lyocell fiber, and preliminarily curing at a first set temperature to obtain a preliminarily cured Lyocell fiber, wherein the mass percentage of the crosslinking agent solute in the crosslinking agent solution is 0.1%-10%, defined as a; the mass percentage of the catalyst solute in the catalyst solution is (0-5%) x a. The crosslinking agent is the basis for the fiber to produce anti-fibrillation, and a too high concentration will significantly increase the cost and make commercial production impossible, and a too low concentration will result in insufficient activity and failure to produce a crosslinked fiber product meeting 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 the energy consumption reduction of the preliminary curing and deep curing processes; and the active groups have a higher concentration under the condition of a low bath ratio, which will further improve the activity of the reaction between the crosslinking agent and the hydroxyl groups 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, carpet crosslinking, finished fiber crosslinking, fiber yarn crosslinking, and fiber fabric crosslinking. That is, the chemical reagent solution can be treated before, after, and during the cutting of the formed Lyocell fiber in the Lyocell fiber production chain, or even on the finished fabric. Specifically, in the nascent Lyocell fiber, there is still a large amount of NMMO solution that needs to be recycled, and the recycling method is to wash the fiber with water to recover NMMO in the water, so there is an economically optimal choice for the catalyst or crosslinking agent addition method at different stages of fiber production. The cellulose crosslinking agent is a chemical substance containing at least two or more active groups that can react with cellulose fibers; when part 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 active groups, ultimately affecting the reactivity of the remaining crosslinking agent and active groups. Changing the reaction conditions of the remaining reaction can promote better crosslinking effect, which is specifically reflected in the changes of reaction temperature, reaction speed, reaction pressure, or reaction pH. Therefore, regardless of the type of crosslinking agent, its reaction with cellulose should be controlled under different conditions to make it occur in steps;

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

[0048] Further, the preliminary curing temperature should be based on the partial reaction of the crosslinking agent; for example, when difluoro-monochloro pyrimidine is used as the crosslinking agent, the optimal curing temperature is 30-40°C; when dichloropyrimidine is used as the crosslinking agent, the optimal preliminary curing temperature is 40-60°C; and when dichloro-s-triazine is used as the crosslinking agent, the optimal reaction temperature is 30-70°C.

[0049] Therefore, the preliminary solidified fiber is washed by the gradient acid-base solution to make the preliminary solidified fiber further react in the gradient acid-base solution.

[0050] The deep solidification reaction can be performed by washing the fiber with one acid-base solution, which is economically advantageous, or by washing the fiber with two or more acid-base solutions, which increases the production cost but improves the product quality, and the fiber is prepared according to the production requirements.

[0051] Step S2: washing the solidified Lyocell fiber to change the electron cloud density distribution of the solidified Lyocell fiber, completing deep solidification, and obtaining a deep solidified Lyocell fiber;

[0052] Step S3: post-treatment of the deep solidified Lyocell fiber to obtain a cross-linked cellulose fiber.

[0053] In the step of washing the solidified Lyocell fiber to change the electron cloud density distribution of the solidified Lyocell fiber, completing deep solidification, and obtaining a deep solidified Lyocell fiber, the solution temperature T of the washed solidified Lyocell fiber is 5×pH+300±12℃, where T is the temperature in Kelvin, and pH is the pH of the solution for washing the solidified Lyocell fiber.

[0054] In the step of washing the solidified Lyocell fiber to change the electron cloud density distribution of the solidified Lyocell fiber, completing deep solidification, and obtaining a deep solidified Lyocell fiber, the solution for washing the solidified Lyocell fiber includes three different gradient acid-base solutions, wherein,

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

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

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

[0058] In the step of washing the solidified Lyocell fiber to change the electron cloud density distribution of the solidified Lyocell fiber, completing deep solidification, and obtaining a deep solidified Lyocell fiber, the solution for washing the solidified Lyocell fiber further includes the first gradient acid-base solution, wherein,

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

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

[0061] The first set temperature ranges from 20 to 95°C, based on the reaction of the cross-linking agent.

[0062] The method of processing during the step of adding the cross-linking agent solution and the catalyst solution to the Lyocell fiber includes one or a combination of tow cross-linking, carpet cross-linking, product fiber cross-linking, fiber yarn cross-linking, and fiber fabric cross-linking.

[0063] The method of processing during the step of adding the cross-linking agent solution and the catalyst solution to the Lyocell fiber, and preliminarily solidifying at the first set temperature to obtain the preliminarily solidified Lyocell fiber,

[0064] If the cross-linking reaction is performed before cutting, the method of preliminarily solidifying includes one or a combination of infrared heating, hot roller heating, microwave heating, radio frequency heating, and steam heating.

[0065] If the cross-linking reaction is performed after cutting, the method of preliminarily solidifying includes one or a combination of infrared heating, microwave heating, radio frequency heating, steam heating, and drying heating.

[0066] The cross-linking agent solution is selected from one or a combination of difluoro-monochloro pyrimidine, dichloro pyrimidine, dichloro quinoxaline pyrimidine, dichloro pyridine, dichloro pyridazine, trichloro pyridazine, difluoro-monochloro pyridazine, bis-monochloro s-triazine, dichloro s-triazine, dichloro triazine, and dichloro phthalazine.

[0067] The catalyst solute is selected from one or a combination of aminobenzenesulfonic acid, aminobenzoic acid, arylamino, sulfonic acid, and phenol.

[0068] The catalyst solution further includes one or a combination of alkaline substances, surfactants, and salts.

[0069] The cross-linking agent solution further includes one or a combination of alkaline substances, surfactants, and salts.

[0070] The basic substance includes one or more of urea, sodium bicarbonate, sodium carbonate, sodium hydroxide, ammonia, sodium phosphate, sodium hypophosphite, potassium hydroxide, sodium acetate, boric acid, and the pH of the basic substance ranges from 8 to 14. The basic substance can provide a dissolving environment and a stable environment for the cross-linking agent, which helps 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 basic substance includes urea, sodium bicarbonate, sodium carbonate, sodium hydroxide, ammonia, sodium phosphate, sodium hypophosphite, potassium hydroxide, sodium acetate, boric acid, and the like. The above-mentioned auxiliary agents can be used alone or in combination.

[0071] The surface active agent includes one or more of penetrant T, abegail B, polyoxyethylene condensate, naphthalene sulfonic acid formaldehyde condensate, fatty amide, sodium dodecyl sulfate, monolauryl phosphate, and potassium dodecyl phosphate. The addition amount of the surface active agent is 0-5% of the mass of the cross-linking agent solute in the cross-linking agent solution. The addition of the surface active agent is beneficial to the uniform distribution of the cross-linking agent in and outside the fiber, reduces the resistance of the cross-linking agent to penetrate into the fiber, and increases the solution permeability, which is beneficial to the significant improvement of uniformity.

[0072] The salt includes one or more of magnesium chloride, sodium chloride, sodium sulfate, potassium sulfate, and potassium chloride. The mass percentage of the salt in the cross-linking agent solution ranges from 0 to 10%. The chemical reaction between the cellulose on the cellulose fiber and the cross-linking agent is the reaction between the ionized cellulose and the cross-linking agent. The addition of the salt is beneficial to the ionization of the cellulose and reduces the charge resistance between the cellulose and various chemical reagents, thereby increasing the final reaction activity. The addition of the salt in the cross-linking agent is beneficial to the occurrence of the cross-linking reaction.

[0073] The salt includes one or more of magnesium chloride, sodium chloride, sodium sulfate, potassium sulfate, and potassium chloride. The mass percentage of the salt in the cross-linking agent solution ranges from 0 to 10%. The chemical reaction between the cellulose on the cellulose fiber and the cross-linking agent is the reaction between the ionized cellulose and the cross-linking agent. The addition of the salt is beneficial to the ionization of the cellulose and reduces the charge resistance between the cellulose and various chemical reagents, thereby increasing the final reaction activity. The addition of the salt in the cross-linking agent is beneficial to the occurrence of the cross-linking reaction.

[0074] Fiber wet rubbing test: FZ / T52019-2018, using lyocell staple fiber industry standard for testing;

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

[0076] The "fiber wet rubbing test" is used to represent the degree of fibrillation resistance of the fiber. The higher the degree of fibrillation resistance, the higher the "wet rubbing resistance value".

[0077] In the fiber wet rubbing test: the final effect is represented by the average value; the cross-linking unevenness is represented by the coefficient of variation of the wet rubbing resistance value; the wet rubbing resistance value greater than 100 times is defined as having cross-linking effect, and the cross-linking rate is defined as the ratio of the fiber having cross-linking effect to the total fiber;

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

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

[0080] Example 1

[0081] Lyocell fibers in the running process of the filament bundle are crosslinked using the method of the present patent:

[0082] (1) The crosslinking agent solution is added to the nascent fiber in a spraying manner, and then the catalyst solution is added to the fiber in a spraying manner after the fiber is rolled dry (the water content is controlled at 70%);

[0083] (2) The above-mentioned fiber is preliminarily cured using a mixed heating method of microwave heating and steam heating;

[0084] (3) Finally, the above-mentioned fiber is washed with a gradient acid-base solution, and finally opened and the like; and the crosslinked fiber is prepared.

[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 x 12 + 300 = 360 K = 87℃

[0089] Note: T2 = 5 x 2 + 300 = 310 K = 37℃

[0090] Note: T3 = 5 x 9 + 300 = 360 K = 72℃

[0091] Comparative Example 1

[0092] (1) The crosslinking agent solution is added to the nascent fiber in a spraying manner, and then the catalyst solution is added to the fiber in a spraying manner after the fiber is rolled dry (the water content is controlled at 70%);

[0093] (2) The above-mentioned fiber is cured using 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] The performance of the fibers produced in Example 1 and Comparative Example 1 is compared as shown in Table 3:

[0099] The performance of the fibers produced in Example 1 and Comparative Example 1 is compared as shown in Table 3

[0100]

[0101] Conclusion: By comparing the performance of the fibers in Example 1 and Comparative Example 1, it can be seen that the mechanical properties of the crosslinked fibers prepared by the process provided in the present patent have no significant difference from those of Comparative Example 1; the crosslinked fibers produced in the present patent have significant improvements in crosslinking effect, crosslinking uniformity and crosslinking rate, especially in crosslinking uniformity; and the unexpected advantage of the crosslinked fibers produced in the present patent is that they have excellent stability, with an S value of only 1. In this way, the crosslinked fiber production process provided in the present patent greatly solves the problems in the subsequent application, providing sufficient protection for product quality stability; in addition, it also effectively avoids problems such as uneven dyeing in subsequent processes.

[0102] Example 2: Crosslinked fibers are produced according to the method shown in Example 1, and the process formula is shown in Table 4. Comparative Examples 2-4: Crosslinked fibers are produced according to the method shown in Comparative Example 1, and the process formula is shown in Table 4.

[0103] Table 4: Process formula and process control of comparative examples

[0104]

[0105] Table 5: Crosslinking effect comparison of comparative examples

[0106]

[0107] From Table 5, it can be seen that:

[0108] Comparative Example 2 and Comparative Example 2 can be seen that without the use of catalyst, it will cause the crosslinking effect of the fiber to decrease significantly, which is due to the catalytic reaction process of the catalyst;

[0109] Comparative Example 2 and Comparative Example 3, Comparative Example 4 can be seen that after reducing the salt material or surfactant, it will cause the crosslinking effect to decrease significantly.

[0110] Example 3

[0111] Lyocell fibers cut and laid into a carpet are crosslinked using the method of the present patent, and the process control is shown in Table 6:

[0112] (1) Add the crosslinking agent solution in the water cutting step, then lay the cut short fibers into a carpet and place them on a conveyor belt, after rolling (moisture content controlled at 70%), add the catalyst solution in a spraying manner for treatment;

[0113] (2) using the mixed heating method of microwave heating and steam heating to preliminarily solidify the above-mentioned fibers;

[0114] (3) finally using gradient acid-base solution to rinse the above-mentioned fibers, and finally performing the step of opening, etc. to prepare the crosslinked fibers.

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

[0116] Comparative Examples 5-6 are produced according to the method described in Example 3, and the process control is shown in Table 6:

[0117] Table 6 Process formula and process control of comparative examples 3

[0118] Crosslinker process control Catalyst process control Preliminary cure process Example 3 10°C, 1 min 10°C, 1 min 55°C, 3 min Comparative Example 5 30°C, 1 min 30°C, 1 min 55°C, 3 min Comparative Example 6 10°C, 3 min 10°C, 3 min 70°C, 3 min

[0119] Table 7 Crosslinking effect comparison of comparative examples 2

[0120]

[0121] From Table 6 and Table 7, it can be seen that:

[0122] It can be seen from Comparative Example 3 and Comparative Example 5 that, under the condition that other processes remain unchanged, the temperature of the crosslinking agent and the catalyst is increased in the comparative example, although there is no significant effect on the average value of the crosslinking wet rubbing resistance, but after the temperature is increased, the crosslinking unevenness rate is significantly increased; this is because the crosslinking agent does not occur chemical reaction at low temperature, and is easy to be evenly distributed on the fiber; while at high temperature, the cellulose hydroxyl group will react with the crosslinking to cause solidification phenomenon before being evenly distributed, affecting the uniform distribution of the crosslinking agent on the fiber; therefore, after the temperature is increased, the uniformity of the fiber is significantly decreased;

[0123] It can be seen from Comparative Example 3 and Comparative Example 6 that increasing the temperature of the preliminary solidification process will instead reduce the crosslinking effect, which is because the temperature is too high to make the crosslinking agent react with the fiber to form steric hindrance, making it difficult for the remaining crosslinking agent to occur crosslinking reaction, finally resulting in a significant decrease in the crosslinking effect; while Example 3 is gradually increased in temperature, and the whole reaction process is controlled gently, so that the crosslinking agent gradually reacts, and finally the crosslinking effect is significantly improved.

[0124] Although the preferred embodiments of the present application have been described, those skilled in the art can make further changes and modifications to these embodiments once they know the basic inventive concept. Therefore, the appended claims are intended to be interpreted as including all changes and modifications falling within the scope of the present application.

[0125] Obviously, many modifications and variations of the present application are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims and their equivalents, the application can be practiced otherwise than as specifically described.

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 at a first set temperature to obtain a preliminarily cured Lyocell fiber; flushing the solidified Lyocell fiber to change the electron cloud density distribution of the solidified Lyocell fiber; And complete deep curing to obtain deeply cured Lyocell fiber; Post-processing the deeply cured Lyocell fibers to obtain cross-linked cellulose fibers; The crosslinking agent solution comprises, by weight percentage, 2% difluorochloropyrimidine, 1% sodium carbonate, 1% sodium sulfate, and 0.01% rapid penetrant T, and the temperature of the crosslinking agent solution is 15° C.; The catalyst solution comprises, by weight percentage, 0.01% methanesulfonic acid and 0.1% potassium hydroxide, and the temperature of the catalyst solution is 15° C.; The first preset temperature is 55°C; The step of rinsing the cured Lyocell fiber includes: rinsing with first, second and third gradient acid-base solutions in sequence, wherein the pH value range of the first gradient acid-base solution is 12-14, the pH value of the second gradient acid-base solution is 2, and the pH value range of the third gradient acid-base solution is 9-13.

2. The method for preparing cross-linked cellulose fibers according to claim 1, wherein: 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 acid-base 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, wherein: 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.

4. The method for preparing cross-linked cellulose fibers according to claim 1, wherein: 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: crosslinking of the fiber bundle, crosslinking of the fiber laid into a silk carpet after cutting, crosslinking of the finished fiber, crosslinking of the fiber yarn and crosslinking of the fiber fabric.

5. The method for preparing cross-linked cellulose fibers according to claim 1, wherein: The steps 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 include: A cross-linking reaction is carried out before the fibers are cut, and the specific method of the preliminary curing includes one or a combination of infrared heating, hot roller heating, microwave heating, radio frequency heating, and steam heating; Alternatively, heating is performed after the fibers are cut, and the specific method of the preliminary curing includes infrared heating, microwave heating, radio frequency heating, steam heating, or a combination of these.

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