Lyocell short fiber, circulating system and method for treating Lyocell short fiber and performance testing method of Lyocell short fiber

Abstract

The invention discloses a Lyocell short fiber, a circulating system and method for treating the Lyocell short fiber and a performance testing method of the Lyocell short fiber, and belongs to the technical field of fiber treatment methods. The system comprises a circulating unit and a circulating tank, the circulating unit comprises a first compression roller and a second compression roller, Lyocell fibers to be treated are pressed out from the position between the first compression roller and the second compression roller, pressed-out Lyocell fibers and pressed-out solution are obtained, and the pressed-out solution flows back to the circulating tank. The method for treating the Lyocell short fibers comprises the following steps: obtaining Lyocell fiber filaments; cutting off to obtain Lyocell short fibers; lapping and forming to obtain a Lyocell short fiber forming body; sequentially passing through two sets of systems to obtain a cyclically treated Lyocell short fiber intermediate product; carrying out a cross-linking reaction to obtain a cross-linked Lyocell short fiber intermediate product; and carrying out post-treatment to obtain a final treatment product of the Lyocell short fibers. The fiber is prepared by the method. The performance testing method can be used for testing the performance of the Lyocell short fiber. The uniformity of the fiber crosslinking performance can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of fiber processing methods, and in particular to Lyocell short fibers, a circulation system and method for processing the same, and a performance testing method thereof. Background Art

[0002] Lyocell fiber is a cellulose fiber prepared by dry-jet wet spinning with N-methylmorpholine-N-oxide (NMMO) as solvent. Lyocell fiber uses wood pulp, bamboo pulp and cotton pulp as raw materials. During the preparation process, the recovery rate of N-methylmorpholine-N-oxide (NMMO) reaches more than 99.5%, which is economical and applicable. The production process is green and environmentally friendly and pollution-free. However, the fibrillation tendency of Lyocell fiber causes pilling of its textiles during the washing process, which seriously limits the application of Lyocell fiber. Summary of the invention

[0003] In view of this, the present invention provides a Lyocell staple fiber, a circulation system and method for processing the same, and a performance testing method thereof. The circulation system and method for processing the Lyocell staple fiber can improve the uniformity of the fiber cross-linking performance, thereby being more suitable for practical use.

[0004] In order to achieve the above first object, the technical scheme of the circulation system for processing Lyocell short fibers provided by the present invention is as follows:

[0005] The circulation system for processing Lyocell short fibers provided by the present invention comprises a circulation unit and a circulation tank.

[0006] The circulation unit comprises a first pressing roller and a second pressing roller, and the Lyocell fiber to be treated is pressed out from between the first pressing roller and the second pressing roller to obtain the pressed Lyocell fiber and the pressed solution.

[0007] The pressed solution is returned to the circulation tank.

[0008] The circulation system for processing Lyocell short fibers provided by the present invention can be further implemented by adopting the following technical measures.

[0009] As a preference,

[0010] The circulation unit includes at least one circulation unit monomer, and the circulation tank includes a circulation tank monomer.

[0011] The liquid outlet of the circulation unit cell is communicated with the liquid inlet of the circulation tank cell, and the liquid outlet of the circulation tank cell is communicated with the liquid inlet of the circulation unit cell.

[0012] As a preference,

[0013] The circulation unit comprises n circulation unit monomers and n circulation tank monomers.

[0014] The liquid outlet of the first circulation unit monomer is communicated with the liquid inlet of the first circulation tank monomer, and the liquid outlet of the first circulation tank monomer is communicated with the liquid inlet of the second circulation unit monomer;

[0015] The liquid outlet of the second circulation unit monomer is communicated with the liquid inlet of the second circulation tank monomer, and the liquid outlet of the second circulation tank monomer is communicated with the liquid inlet of the third circulation unit monomer;

[0016] And so on.

[0017] The liquid outlet of the last circulation unit monomer is communicated with the liquid inlet of the last circulation tank monomer, and the liquid outlet of the last circulation tank monomer is communicated with the liquid inlet of the first circulation unit monomer.

[0018] In order to achieve the above second purpose, the technical solution of the method for processing Lyocell short fibers provided by the present invention is as follows:

[0019] The method for processing Lyocell short fibers provided by the present invention comprises the following steps:

[0020] Prepare two sets of circulation systems for processing Lyocell staple fibers provided by the present invention, namely, a first set of circulation systems for processing Lyocell staple fibers and a second set of circulation systems for processing Lyocell staple fibers, wherein one of the first set of circulation systems for processing Lyocell staple fibers and the second set of circulation systems for processing Lyocell staple fibers is a crosslinking agent circulation system and the other is an alkali auxiliary agent circulation system;

[0021] Obtain Lyocell fiber filament;

[0022] Cutting the Lyocell fiber filaments to obtain Lyocell short fibers;

[0023] Laying the Lyocell short fibers into a web to obtain a Lyocell short fiber molded body;

[0024] The Lyocell short fiber molded body is sequentially passed through a first set of circulation system for processing Lyocell short fibers and a second set of circulation system for processing Lyocell short fibers to obtain a Lyocell short fiber intermediate product that has been circulated and processed;

[0025] The Lyocell short fiber intermediate product that has been recycled undergoes a cross-linking reaction to obtain a cross-linked Lyocell short fiber intermediate product;

[0026] The cross-linked Lyocell short fiber intermediate product is post-treated to obtain the final processed product of Lyocell short fiber.

[0027] The method for processing Lyocell short fibers provided by the present invention can be further implemented by adopting the following technical measures.

[0028] Preferably, in the step of obtaining a Lyocell short fiber intermediate product after cyclic treatment by sequentially passing through a first set of circulation system for treating Lyocell short fibers and a second set of circulation system for treating Lyocell short fibers, the application time of the first set of circulation system for treating Lyocell short fibers is in the range of 1min-15min, and the application time of the second set of circulation system for treating Lyocell short fibers is in the range of 1min-30min.

[0029] Preferably, the crosslinking agent is a dichlorotriazine crosslinking agent; the mass percentage of the solute in the crosslinking agent ranges from 0.3% to 10%; and the temperature for applying the crosslinking agent ranges from 0°C to 100°C.

[0030] Preferably, the alkali auxiliary agent includes one or more of ammonia water, sodium hydroxide, potassium hydroxide, sodium bicarbonate, sodium carbonate, sodium sulfate, and sodium phosphate; the mass percentage of the solute in the alkali auxiliary agent is in the range of 0.3%-6%; and the temperature range for applying the alkali auxiliary agent is 10°C-100°C.

[0031] Preferably, in the step of forming the Lyocell short fibers into a web to obtain a Lyocell short fiber molded body, the thickness of the Lyocell short fiber molded body ranges from 0.1 cm to 20 cm.

[0032] Preferably, in the step of cross-linking the circulated Lyocell short fiber intermediate product to obtain the cross-linked Lyocell short fiber intermediate product, the cross-linking reaction temperature is in the range of 60°C-150°C; the heating method for obtaining the cross-linking reaction temperature is selected from a combination of one or more of radio frequency heating, microwave heating, oven heating, steam heating, and fiber insulation, and the heating duration is in the range of 3min-15min.

[0033] Preferably, the cross-linked Lyocell staple fiber intermediate product is subjected to post-processing to obtain the final processed product of Lyocell staple fiber, and the post-processing includes cleaning, oiling, untangling, drying and packaging.

[0034] Preferably, the cleaning agent is selected from water or an acidic solution, the acid in the acidic solution is selected from one or more of acetic acid, hydrochloric acid, sulfuric acid, and oxalic acid, and the mass percentage of the solute in the acidic solution ranges from 0.005% to 5%.

[0035] In order to achieve the third purpose above, the technical solution of Lyocell short fibers provided by the present invention is as follows:

[0036] The Lyocell short fibers provided by the present invention are obtained by processing the Lyocell short fibers provided by the present invention.

[0037] In order to achieve the fourth objective, the technical solution of the method for testing the performance of Lyocell short fibers provided by the present invention is as follows:

[0038] The method for testing the performance of Lyocell short fibers provided by the present invention comprises the following steps:

[0039] The fiber fineness is tested according to GB / T 14335-2008 standard;

[0040] The dry breaking strength is tested according to GB / T 14337-2008 standard;

[0041] The wet wear times are tested according to FZT 52019-2018 standard;

[0042] The formulas of the Holler factors F1 and F2 used to reflect the comprehensive performance of fiber mechanical properties are:

[0043] F1=-1.109+0.03992·FFk-0.06502·FDk+0.04634·FFn-0.04048·FDn+0.08936·NM+0.02748·SFk+0.02559·KFk

[0044] F2=-7.070+0.02771·FFk+0.04335·FDk+0.02541·FFn+0.03885·FDn-0.01542·NM+0.2891·SFk+0.1640·KFk

[0045] Wherein, FFk is the dry breaking strength after moisture conditioning, cN / tex, FDk is the dry breaking elongation after moisture conditioning, %, FFn is the wet breaking strength, cN / tex, FDn is the wet breaking elongation, %, NM is the wet modulus at 5% elongation, cN / tex / 5%, SFk is the hook dry strength after moisture conditioning, cN / tex, KFk is the knot strength after moisture conditioning, cN / tex, and the above parameters are all tested according to GB / T14337-2008 standard;

[0046] The instrument used for the fiber anti-beating number test is a beating instrument. Take 0.01g of fiber, add 100g of deionized water into a bag and then put it in the beating instrument for beating. Set the beating frequency to 7 times / s. Finally, observe the fibrillation of the fiber after beating under an optical microscope to obtain the test result of the fiber anti-beating number.

[0047] The present invention adds the alkali auxiliary agent and the crosslinking agent separately, and sets up two circulation systems, and respectively adds the high-concentration alkali auxiliary agent and the high-concentration crosslinking agent in production, which can avoid direct contact between the crosslinking agent and the alkali auxiliary agent, thus greatly reducing the hydrolysis rate of the crosslinking agent. At the same time, each circulation system is provided with multiple circulation units, which effectively improves the utilization rate of the crosslinking agent, increases the anti-fibrillation performance of the fiber, and greatly improves the uniformity of the fiber crosslinking performance.

[0048] The content of crosslinking agent on the fiber can be deduced by measuring the nitrogen content of the fiber. The utilization rate of the crosslinking agent is the ratio of the content of crosslinking agent on the fiber to the amount of crosslinking agent added.

[0049] The invention also relates to textile products, which are spun with the lyocell staple fibers prepared according to the invention, and the properties of the yarns produced under different processes are compared. DETAILED DESCRIPTION

[0050] In view of this, the present invention provides a Lyocell staple fiber, a circulation system and method for processing the same, and a performance testing method thereof. The circulation system and method for processing the Lyocell staple fiber can improve the uniformity of the fiber cross-linking performance, thereby being more suitable for practical use.

[0051] After arduous efforts, the inventor discovered that

[0052] Lyocell fibers have high crystallinity and orientation. They easily absorb water and swell in a wet environment, which destroys the hydrogen bonds between the fibrils and weakens the lateral binding force. Therefore, under the action of external mechanical force, the fibrils will separate from each other, thereby peeling off the fiber surface and causing fibrillation.

[0053] Many researchers have done a lot of research in this area, trying to find ways to reduce its fibrillation tendency. Among them, the products that have been successfully marketed are Lenzing's Lyocell LF and Tencel A100 cross-linked fibers. The cross-linking agent used in Lyocell LF cross-linked fiber is 2,4-dichloro-6-hydroxy-1,3,5-triazine sodium salt (NHDT), and the cross-linking agent used in Tencel A100 cross-linked fiber is 1,3,5-triacryloylhexahydro-1,3,5-triazine (TAHT). It can improve the fibrillation phenomenon, but the specific process flow is not mentioned, and the recycling process is not used to prepare the cross-linked fiber.

[0054] There is also a technical solution that uses NHDT as a crosslinking agent. The fiber contacts the crosslinking agent in the form of a filament bundle and reacts. The process is called "tow crosslinking". However, the "tow crosslinking" process has the disadvantages of high equipment cost and large floor space.

[0055] 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 Lyocell short fiber, a circulation system and method for processing the same, and a performance test method thereof, as well as its specific implementation, structure, features and effects proposed by the present invention 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.

[0056] 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.

[0057] Circulation system for processing Lyocell staple fibers

[0058] The circulation system for treating Lyocell short fibers provided by the present invention comprises a circulation unit and a circulation tank. The circulation unit comprises a first pressing roller and a second pressing roller, and the Lyocell fibers to be treated are pressed out from between the first pressing roller and the second pressing roller to obtain pressed Lyocell fibers and pressed solution. The pressed solution flows back to the circulation tank.

[0059] The circulation unit includes at least one circulation unit monomer, the circulation tank includes a circulation tank monomer, the liquid outlet of the circulation unit monomer is connected to the liquid inlet of the circulation tank monomer, and the liquid outlet of the circulation tank monomer is connected to the liquid inlet of the circulation unit monomer.

[0060] Wherein, the circulation unit includes n circulation unit monomers and n circulation tank monomers, the liquid outlet of the first circulation unit monomer is connected to the liquid inlet of the first circulation tank monomer, and the liquid outlet of the first circulation tank monomer is connected to the liquid inlet of the second circulation unit monomer; the liquid outlet of the second circulation unit monomer is connected to the liquid inlet of the second circulation tank monomer, and the liquid outlet of the second circulation tank monomer is connected to the liquid inlet of the third circulation unit monomer; and so on, the liquid outlet of the last circulation unit monomer is connected to the liquid inlet of the last circulation tank monomer, and the liquid outlet of the last circulation tank monomer is connected to the liquid inlet of the first circulation unit monomer.

[0061] Method for processing Lyocell short fibers

[0062] The method for processing Lyocell short fibers provided by the present invention comprises the following steps:

[0063] Step S1: preparing two sets of circulation systems for processing Lyocell staple fibers provided by the present invention, namely, a first set of circulation systems for processing Lyocell staple fibers and a second set of circulation systems for processing Lyocell staple fibers, wherein the first set of circulation systems for processing Lyocell staple fibers and the second set of circulation systems for processing Lyocell staple fibers, one of which is a crosslinking agent circulation system and the other is an alkali auxiliary agent circulation system;

[0064] Step S2: Obtaining Lyocell fiber filaments;

[0065] Step S3: cutting the Lyocell fiber filaments to obtain Lyocell short fibers;

[0066] Step S4: forming a Lyocell short fiber web to obtain a Lyocell short fiber molded body;

[0067] Step S5: the Lyocell short fiber molded body is sequentially passed through the first set of Lyocell short fiber processing circulation system and the second set of Lyocell short fiber processing circulation system to obtain a Lyocell short fiber intermediate product that has been cyclically processed;

[0068] Step S6: The Lyocell short fiber intermediate product that has been subjected to the recycling treatment undergoes a cross-linking reaction to obtain a cross-linked Lyocell short fiber intermediate product;

[0069] Step S7: The cross-linked Lyocell short fiber intermediate product is post-treated to obtain the final processed product of Lyocell short fiber.

[0070] Among them, in the step of obtaining the Lyocell short fiber intermediate product after cyclic treatment by sequentially passing through the first set of circulation system for treating Lyocell short fibers and the second set of circulation system for treating Lyocell short fibers, the application time of the first set of circulation system for treating Lyocell short fibers ranges from 1min to 15min, and the application time of the second set of circulation system for treating Lyocell short fibers ranges from 1min to 30min.

[0071] The crosslinking agent is a dichlorotriazine crosslinking agent; the mass percentage content of the solute in the crosslinking agent ranges from 0.3% to 10%; and the temperature for applying the crosslinking agent ranges from 0°C to 100°C.

[0072] The alkali auxiliary agent includes one or more of ammonia water, sodium hydroxide, potassium hydroxide, sodium bicarbonate, sodium carbonate, sodium sulfate, and sodium phosphate; the mass percentage of the solute in the alkali auxiliary agent is in the range of 0.3%-6%; and the temperature range for applying the alkali auxiliary agent is 10°C-100°C.

[0073] In the step of forming the Lyocell short fibers into a web to obtain a Lyocell short fiber molded body, the thickness of the Lyocell short fiber molded body ranges from 0.1 cm to 20 cm.

[0074] Among them, in the step of obtaining the cross-linked Lyocell short fiber intermediate product through cross-linking reaction of the cyclic treated Lyocell short fiber intermediate product, the cross-linking reaction temperature ranges from 60°C to 150°C; the heating method for obtaining the cross-linking reaction temperature is selected from a combination of one or more of radio frequency heating, microwave heating, oven heating, steam heating, and fiber insulation, and the heating duration ranges from 3min to 15min.

[0075] Among them, the cross-linked Lyocell short fiber intermediate product is post-processed to obtain the final processed product of Lyocell short fiber, and the post-processing includes cleaning, oiling, untangling, drying and packaging.

[0076] The cleaning agent is selected from water or an acidic solution, the acid in the acidic solution is selected from one or more of acetic acid, hydrochloric acid, sulfuric acid, and oxalic acid, and the mass percentage of the solute in the acidic solution ranges from 0.005% to 5%.

[0077] Lyocell short fibers

[0078] The Lyocell short fibers provided by the present invention are obtained by processing the Lyocell short fibers provided by the present invention.

[0079] Method for testing the performance of Lyocell short fibers

[0080] The method for testing the performance of Lyocell short fibers provided by the present invention comprises the following steps:

[0081] The fiber fineness is tested according to GB / T 14335-2008 standard;

[0082] The dry breaking strength is tested according to GB / T 14337-2008 standard;

[0083] The wet wear times are tested according to FZT 52019-2018 standard;

[0084] The formulas of the Holler factors F1 and F2 used to reflect the comprehensive performance of fiber mechanical properties are:

[0085] F1=-1.109+0.03992·FFk-0.06502·FDk+0.04634·FFn-0.04048·FDn+0.08936·NM+0.02748·SFk+0.02559·KFk

[0086] F2=-7.070+0.02771·FFk+0.04335·FDk+0.02541·FFn+0.03885·FDn-0.01542·NM+0.2891·SFk+0.1640·KFk

[0087] Wherein, FFk is the dry breaking strength after moisture conditioning, cN / tex, FDk is the dry breaking elongation after moisture conditioning, %, FFn is the wet breaking strength, cN / tex, FDn is the wet breaking elongation, %, NM is the wet modulus at 5% elongation, cN / tex / 5%, SFk is the hook dry strength after moisture conditioning, cN / tex, KFk is the knot strength after moisture conditioning, cN / tex, and the above parameters are all tested according to GB / T14337-2008 standard;

[0088] The fiber anti-beating number test uses a beating instrument. Take 0.01g of fiber, add 100g of deionized water into a bag and then put it in the beating instrument for beating. Set the beating frequency to 7 times / s. Finally, observe the fibrillation of the fiber after beating under an optical microscope to obtain the fiber anti-beating number test result. The anti-beating number specified in the embodiment of the present invention refers to the occurrence of fibrillation in 10% or more of the fibers.

[0089] Example 1

[0090] Continuous cellulose filaments were spun by a known method to form fiber bundles and washed with water, then cut into short fibers, and washed continuously to remove NMMO solvent from the fibers; the short fibers were laid into a fiber web and pressed into a molded body with a thickness of 2 cm; the fibers were respectively fed into a crosslinking agent (NHDT) circulation system and an alkali auxiliary agent (Na2CO3+Na2SO4) circulation system, and heated with steam at a temperature of 100°C, and then washed with oxalic acid solution, and then washed with pure water to neutrality, and then oiled, unwrapped, and dried to prepare lyocell fibers with anti-fibrillation effect. The results are shown in Table 1.

[0091] Example 2

[0092] Continuous cellulose filaments were spun by a known method to form fiber bundles and washed with water, then cut into short fibers, and washed continuously to remove NMMO solvent from the fibers; the short fibers were laid into a fiber web and pressed into a molded body with a thickness of 2.5 cm; the fibers were respectively put into an alkali auxiliary agent (Na3PO4) circulation system and a crosslinking agent (NHDT) circulation system, and heated by microwave at a heating temperature of 90°C, and then washed with oxalic acid solution, and then washed with pure water to neutrality, and then oiled, unwrapped, and dried to prepare lyocell fibers with anti-fibrillation effect. The results are shown in Table 1.

[0093] Example 3

[0094] Continuous cellulose filaments were spun by a known method to form fiber bundles and washed with water, then cut into short fibers, and washed continuously to remove NMMO solvent from the fibers; the short fibers were laid into a fiber web and pressed into a molded body with a thickness of 3 cm; the fibers were respectively fed into a crosslinking agent (NHDT) circulation system and an alkali auxiliary agent (Na2CO3+Na2SO4+Na3PO4) circulation system, and heated with steam at a temperature of 95°C, and then washed with acetic acid solution, and then washed with pure water to neutrality, and then oiled, unwrapped, and dried to prepare lyocell fibers with anti-fibrillation effect. The results are shown in Table 1.

[0095] Example 4

[0096] Continuous cellulose filaments were spun by a known method to form fiber bundles and washed with water, then cut into short fibers, and washed continuously to remove NMMO solvent from the fibers; the short fibers were laid into a fiber web and pressed into a molded body with a thickness of 3.5 cm; the fibers were respectively put into an alkali auxiliary agent (NaHCO3+KOH+Na3PO4) circulation system and a crosslinking agent (NHDT) circulation system, heated by microwave at a temperature of 85°C, then washed with acetic acid solution, and then washed with pure water to neutrality, and then oiled, unwrapped, and dried to prepare lyocell fibers with anti-fibrillation effect. The results are shown in Table 1.

[0097] Example 5

[0098] Continuous cellulose filaments were spun by a known method to form fiber bundles and washed with water, then cut into short fibers, and washed continuously to remove NMMO solvent from the fibers; the short fibers were laid into a fiber web and pressed into a molded body with a thickness of 4 cm; the fibers were respectively fed into a crosslinking agent (NHDT) circulation system and an alkali auxiliary agent (KOH+Na2CO3+Na2SO4) circulation system, heated by microwave at a temperature of 90°C, then washed with acetic acid solution, and then washed with pure water to neutralize the fiber web, and then oiled, unwrapped, and dried to prepare lyocell fibers with anti-fibrillation effect. The results are shown in Table 1.

[0099] Example 6

[0100] Continuous cellulose filaments were spun by a known method to form fiber bundles and washed with water, then cut into short fibers, and washed continuously to remove NMMO solvent from the fibers; the short fibers were laid into a fiber web and pressed into a molded body with a thickness of 5 cm; the fibers were respectively placed into an alkali (Na2CO3+NaHCO3+Na3PO4) and a crosslinking agent (NHDT) circulation system, heated by microwave at a temperature of 80°C, then washed with acetic acid solution, and then washed with pure water to neutralize the fiber web, and then oiled, unwrapped, and dried to prepare lyocell fibers with anti-fibrillation effect. The results are shown in Table 1.

[0101] Table 1

[0102]

[0103] The present invention also relates to textile products. The lyocell staple fibers prepared according to the present invention are spun and the properties of the yarns produced under different processes are compared, as shown in Table 2.

[0104] Table 2

[0105] Example Example 4 Example 3 Not cross-linked Neps (+140%) 126 128 72 Neps (+200%) 41 50 26 Yarn strength (cN / tex) 23 24 22.7 Elongation at break (%) 7.3 7.5 7.2 Linear density (tex) R10.6 R11.6 R9.7

[0106] It can be seen from Table 2 that the yarn prepared from the fiber provided in the embodiment of the present invention has higher yarn strength and elongation at break, and has higher spinning processability.

[0107] 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.

[0108] 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 circulation system for processing Lyocell short fibers, characterized in that: Including circulation unit and circulation tank, The circulation unit comprises a first pressing roller and a second pressing roller, and the Lyocell fiber to be treated is pressed out from between the first pressing roller and the second pressing roller to obtain the pressed Lyocell fiber and the pressed solution. The pressed solution is returned to the circulation tank.

2. The circulation system for processing Lyocell short fibers according to claim 1, characterized in that: The circulation unit includes at least one circulation unit monomer, and the circulation tank includes a circulation tank monomer. The liquid outlet of the circulation unit cell is communicated with the liquid inlet of the circulation tank cell, and the liquid outlet of the circulation tank cell is communicated with the liquid inlet of the circulation unit cell.

3. The circulation system for processing Lyocell short fibers according to claim 1, characterized in that: The circulation unit comprises n circulation unit monomers and n circulation tank monomers. The liquid outlet of the first circulation unit monomer is communicated with the liquid inlet of the first circulation tank monomer, and the liquid outlet of the first circulation tank monomer is communicated with the liquid inlet of the second circulation unit monomer; The liquid outlet of the second circulation unit monomer is communicated with the liquid inlet of the second circulation tank monomer, and the liquid outlet of the second circulation tank monomer is communicated with the liquid inlet of the third circulation unit monomer; And so on. The liquid outlet of the last circulation unit monomer is communicated with the liquid inlet of the last circulation tank monomer, and the liquid outlet of the last circulation tank monomer is communicated with the liquid inlet of the first circulation unit monomer.

4. A method for processing Lyocell short fibers, characterized in that: The following steps are involved: Prepare two sets of circulation systems for treating Lyocell staple fibers as described in any one of claims 1 to 3, which are respectively a first set of circulation systems for treating Lyocell staple fibers and a second set of circulation systems for treating Lyocell staple fibers, wherein one of the first set of circulation systems for treating Lyocell staple fibers and the second set of circulation systems for treating Lyocell staple fibers is a crosslinking agent circulation system and the other is an alkali auxiliary agent circulation system; Obtain Lyocell fiber filament; Cutting the Lyocell fiber filaments to obtain Lyocell short fibers; Laying the Lyocell short fibers into a web to obtain a Lyocell short fiber molded body; The Lyocell short fiber molded body is sequentially passed through a first set of circulation system for processing Lyocell short fibers and a second set of circulation system for processing Lyocell short fibers to obtain a Lyocell short fiber intermediate product that has been circulated and processed; The Lyocell short fiber intermediate product that has been recycled undergoes a cross-linking reaction to obtain a cross-linked Lyocell short fiber intermediate product; The cross-linked Lyocell short fiber intermediate product is post-treated to obtain the final processed product of Lyocell short fiber.

5. The method of Lyocell short fibers according to claim 4, characterized in that: The Lyocell short fiber molding is sequentially subjected to a first set of circulation system for treating Lyocell short fibers and a second set of circulation system for treating Lyocell short fibers to obtain a Lyocell short fiber intermediate product after circulation treatment. During the step of applying the first set of circulation system for treating Lyocell short fibers for a time ranging from 1 min to 15 min, and applying the second set of circulation system for treating Lyocell short fibers for a time ranging from 1 min to 30 min.

6. The method for processing Lyocell short fibers according to claim 4, characterized in that: The cross-linking agent is a dichloro-s-triazine cross-linking agent; the mass percentage content of the solute in the cross-linking agent ranges from 0.3% to 10%; and the temperature for applying the cross-linking agent ranges from 0°C to 100°C.

7. The method for processing Lyocell short fibers according to claim 4, characterized in that: The alkali auxiliary agent includes one or more of ammonia water, sodium hydroxide, potassium hydroxide, sodium bicarbonate, sodium carbonate, sodium sulfate, and sodium phosphate; the mass percentage content of the solute in the alkali auxiliary agent is in the range of 0.3%-6%; the temperature range for applying the alkali auxiliary agent is 10°C-100°C.

8. The method for processing Lyocell short fibers according to claim 4, characterized in that: In the step of forming the Lyocell short fibers into a web to obtain a Lyocell short fiber molded body, the thickness of the Lyocell short fiber molded body ranges from 0.1 cm to 20 cm; Preferably, in the step of cross-linking the Lyocell short fiber intermediate product after the cyclic treatment to obtain the cross-linked Lyocell short fiber intermediate product, the cross-linking reaction temperature is in the range of 60°C-150°C; the heating method for obtaining the cross-linking reaction temperature is selected from a combination of one or more of radio frequency heating, microwave heating, oven heating, steam heating, and fiber insulation, and the heating duration is in the range of 3min-15min; Preferably, the cross-linked Lyocell short fiber intermediate product is subjected to post-treatment to obtain the final processed product of Lyocell short fiber, wherein the post-treatment includes washing, oiling, untangling, drying and packaging; Preferably, the cleaning agent is selected from water or an acidic solution, the acid in the acidic solution is selected from one or more of acetic acid, hydrochloric acid, sulfuric acid, and oxalic acid, and the mass percentage of the solute in the acidic solution ranges from 0.005% to 5%.

9. A Lyocell short fiber, characterized in that: The fiber is obtained by processing the Lyocell short fiber according to any one of claims 4 to 8.

10. A method for testing the performance of the Lyocell short fiber according to claim 9, characterized in that: The following steps are involved: The fiber fineness is tested according to GB / T 14335-2008 standard; The dry breaking strength is tested according to GB / T 14337-2008 standard; The wet wear times are tested according to FZT 52019-2018 standard; The formulas of the Holler factors F1 and F2 used to reflect the comprehensive performance of fiber mechanical properties are: F1=-1.109+0.03992·FFk-0.06502·FDk+0.04634·FFn-0.04048·FDn+0.08936·NM+0.02748·SFk+0.02559·KFk F2=-7.070+0.02771·FFk+0.04335·FDk+0.02541·FFn+0.03885·FDn-0.01542·NM+0.2891·SFk+0.1640·KFk Wherein, FFk is the dry breaking strength after moisture conditioning, cN / tex, FDk is the dry breaking elongation after moisture conditioning, %, FFn is the wet breaking strength, cN / tex, FDn is the wet breaking elongation, %, NM is the wet modulus at 5% elongation, cN / tex / 5%, SFk is the hook dry strength after moisture conditioning, cN / tex, KFk is the knot strength after moisture conditioning, cN / tex, and the above parameters are all tested according to GB / T 14337-2008 standard; The instrument used for the fiber anti-beating number test is a beating instrument. Take 0.01g of fiber, add 100g of deionized water into a bag and then put it in the beating instrument for beating. Set the beating frequency to 7 times / s. Finally, observe the fibrillation of the fiber after beating under an optical microscope to obtain the test result of the fiber anti-beating number.

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