Anti-fibrillation green finishing method for lyocell fabric

Abstract

The invention discloses an anti-fibrillation green finishing method for lyocell fabric. The anti-fibrillation green finishing method comprises the following steps: (1) preparing cation modified treatment liquid with the concentration of 2-3%; (2) soaking the lyocell fabric in the treating fluid; 3, the rotating speed of the infrared dyeing machine is set to be 60 r / min, the temperature is increased to 55-65 DEG C from 20 DEG C at the speed of 3 DEG C / min, operation continues for 25-35 min, and then the temperature is reduced to 40 DEG C at the speed of 6 DEG C / min; (4) washing with water and drying at 60 DEG C; (5) preparing a polyacrylic acid emulsion with the concentration of 1-5g / L; (6) soaking the cation modified lyocell fabric in a polyacrylic acid emulsion; 7, the rotating speed of the infrared dyeing machine is set to be 60 r / min, the temperature is increased to 55-65 DEG C from 20 DEG C at the speed of 3 DEG C / min, operation continues for 25-35 min, and then the temperature is reduced to 40 DEG C at the speed of 6 DEG C / min; and (8) pre-baking is conducted firstly, and then baking is conducted at the high temperature of 140-160 DEG C for 4-6 min. According to the invention, the fiber fibrillation tendency in the production and use processes of the lyocell fabric is effectively reduced, the problem of fiber strength loss is solved, the consumption of chemical additives is greatly reduced, and the environmental pollution is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of textile functional finishing, and particularly relates to a green finishing method for fibrillation prevention of Lyocell fabrics. Background Art

[0002] Lyocell fiber is a regenerated cellulose fiber spun from wood pulp dissolved in NMMO solution. Since the fiber production process is non-toxic and pollution-free, and the solvent used can be recycled, it is hailed as a new type of green fiber in the future. The comfort of Lyocell fiber is comparable to that of cotton fiber, with the feel of silk fiber and the drape of viscose fiber, good moisture absorption and air permeability, and good wash size stability. It combines the advantages of synthetic fiber and natural cellulose fiber, and is one of the best and most promising textile raw materials in the market feedback this century.

[0003] However, under the action of the drawing stage in the spinning production process of Lyocell fiber, the crystallization of the fiber tends to be arranged longitudinally along the fiber, making it have structural characteristics such as high crystallinity and high orientation degree. As a result, the transverse binding force between the macromolecular chains of the fiber is much lower than the longitudinal binding force. This obvious anisotropic characteristic and the presence of a large number of active free hydroxyl groups in the amorphous region of the fiber make the Lyocell fiber have a high transverse wet expansion rate when infiltrated in an aqueous solution. When the amorphous region of the fiber expands to a certain extent, some of the hydrogen bonds between the macromolecular chains are damaged, weakening the binding force between the fibrils. At this time, if the fiber is simultaneously subjected to external artificial rubbing or stress such as the frictional force between the fibers, fibrillation is likely to occur. In the case of severe fibrillation, the generated fibrils will entangle into balls on the fabric surface, affecting the appearance of the fabric.

[0004] At present, the widely adopted method for controlling fibrillation of Lyocell fibers is post-treatment, that is, in the printing and dyeing processing stage, through cross-linking agents and high-temperature treatment means, chemical bonds are formed between cellulose molecular chains, thereby inhibiting the fibrillation phenomenon of ordinary Lyocell fibers. The purpose is to increase the lateral force between fibrils in Lyocell fibers. The cellulose macromolecular chain contains a large number of hydroxyl functional groups, which can react with cross-linking agents to generate products such as ethers and esters. Although the currently traditional and widely used high-temperature cross-linking process can significantly improve the anti-fibrillation performance of Lyocell fibers, there are still some defects. Currently, the most typical cross-linking agents are 1,3,5-triacryloyl-hexahydro-1,3,5-triazine (TAHT) and N,N-dimethylol dihydroxyethyl urea (DMDHEU). Both of these cross-linking agents can effectively reduce the formation of fibrils after the fibers are mechanically worn in the wet state. DMDHEU usually requires a higher temperature for curing, and the fiber textiles will suffer serious strength loss after cross-linking. In addition, both cross-linking agents are toxic. Polycarboxylic acids are considered promising cross-linking agents. Citric acid (CA) is one of the most common and green polycarboxylic acids. However, the commercial application of CA in the textile field is still negligible, mainly due to the color change caused by the by-products decomposed after heating. 1,2,3,4-butanetetracarboxylic acid (BTCA) is a more effective cross-linking agent than CA and does not cause yellowing problems. The disadvantage is that the relatively high cost limits its industrial application.

[0005] Therefore, compared with the traditional cross-linking means for anti-fibrillation process, how to be applicable to large-scale factory production, shorten the process flow, reduce costs, effectively reduce the fibrillation tendency of fibers during the production and use of Lyocell fabrics, solve the problem of fiber strength loss, improve the overall quality of fabrics, and greatly reduce the consumption of chemical auxiliaries, and there is no formaldehyde release during the process, has become a difficult problem that technicians in the field of functional finishing of Lyocell fabrics urgently need to solve at present. Summary of the Invention

[0006] Aiming at the deficiencies of the existing technology, the technical problem to be solved by the present invention is to provide a green anti-fibrillation finishing method for Lyocell fabrics, which can effectively reduce the fibrillation tendency of fibers during the production and use of Lyocell fabrics, solve the problem of fiber strength loss, improve the overall quality of fabrics, and greatly reduce the consumption of chemical auxiliaries and reduce environmental pollution.

[0007] To solve the above technical problems, the technical solution adopted by the present invention is: a green anti-fibrillation finishing method for Lyocell fabrics, including the following steps:

[0008] I. Cationic modification:

[0009] (1) Dissolve polydimethyldiallylammonium chloride in deionized water to prepare a cationic modification treatment solution with a concentration of 2 - 3%, and set aside.

[0010] (2) Transfer the cationic modification treatment solution to the dye vat of an infrared dyeing machine, soak the Lyocell fabric in the above treatment solution, and the bath ratio is 1:15 - 1:25.

[0011] (3) Set the rotation speed of the infrared dyeing machine to 60 r / min, heat up from 20°C at a rate of 3°C / min to 55 - 65°C, continue to run at 55 - 65°C for 25 - 35 min, and then cool down to 40°C at a rate of 6°C / min.

[0012] (4) After completion, rinse thoroughly with water and dry at 60°C to obtain the cation-modified Lyocell fabric.

[0013] II. Anionic polymer emulsion treatment:

[0014] (5) Prepare a polyacrylic acid emulsion with a concentration of 1 - 5 g / L, and set aside.

[0015] (6) Transfer the polyacrylic acid emulsion to the dye vat of an infrared dyeing machine, soak the cation-modified Lyocell fabric in the polyacrylic acid emulsion, and the bath ratio is 1:15 - 1:25.

[0016] (7) Set the rotation speed of the infrared dyeing machine to 60 r / min, heat up from 20°C at a rate of 3°C / min to 55 - 65°C, continue to run at 55 - 65°C for 25 - 35 min, and then cool down to 40°C at a rate of 6°C / min.

[0017] III. Pre-drying and curing treatment:

[0018] (8) First pre-dry the Lyocell fabric treated in step (7) at 100°C for 8 - 12 min, and then cure it at a high temperature of 140 - 160°C for 4 - 6 min to obtain the fibrillation-proof Lyocell fabric.

[0019] In the above-mentioned fibrillation-proof green finishing method for Lyocell fabric, in the cationic modification treatment solution in step (1), the concentration of polydimethyldiallylammonium chloride is 2.5%.

[0020] In the above-mentioned fibrillation-proof green finishing method for Lyocell fabric, in step (2), the bath ratio of the cationic modification treatment solution to the Lyocell fabric is 1:20.

[0021] In the above-mentioned fibrillation-proof green finishing method for Lyocell fabric, in step (3), heat up from 20°C at a rate of 3°C / min to 60°C, and continue to run at 60°C for 30 min.

[0022] In the above anti-fibrillation green finishing method for Lyocell fabric, in step (5), the concentration of the polyacrylic acid emulsion is 3 g / L.

[0023] In the above anti-fibrillation green finishing method for Lyocell fabric, in step (6), the bath ratio of the polyacrylic acid emulsion to the cation-modified Lyocell fabric is 1:20.

[0024] In the above anti-fibrillation green finishing method for Lyocell fabric, in step (7), the temperature is raised from 20°C to 60°C at a rate of 3°C / min and maintained at 60°C for 30 min.

[0025] In the above anti-fibrillation green finishing method for Lyocell fabric, in step (8), the Lyocell fabric is pre-dried at 100°C for 10 min and then baked at a high temperature of 150°C for 5 min.

[0026] The advantages of the anti-fibrillation green finishing method for Lyocell fabric of the present invention are as follows: The present invention uses an adsorption means to replace the traditional high-temperature crosslinking. Since the quaternary ammonium group in the cationic modifier is positively charged, it can be adsorbed on the Lyocell fiber through electrostatic attraction. After being modified by the cationic modifier, the surface of the Lyocell fiber changes from negative charge to positive charge. Then, polyacrylic acid is ionized in water to form negatively charged carboxylate ions, which are adsorbed onto the Lyocell fiber modified by the cationic modifier through electrostatic attraction, and through high-temperature baking, the adsorbed polymer particles are melted and diffused to form a film covering the fiber surface. The surface structure of the poly(dimethyldiallylammonium chloride)-modified Lyocell knitted fabric treated with the polyacrylic acid emulsion has been significantly improved, reducing the lateral swelling and axial splitting of the fibers, thereby reducing the formation of nano-scale fibrils. At the same time, the lubricity of the fiber surface is enhanced, reducing the friction and entanglement between the fibers, and a thin film is formed on the fiber surface to cover the peeled fibrils. This thin film effectively prevents the further peeling and falling off of the fibrils, improving the durability and stability of the fiber, and fundamentally solving the problems of fiber strength damage, fabric yellowing, and high cost caused by traditional high-temperature crosslinking, and having obvious industrial application prospects. Brief Description of the Drawings

[0027] Figure 1 is the process flow chart of the anti-fibrillation green finishing method for Lyocell fabric of the present invention;

[0028] Figure 2 is the SEM comparison diagram with 300 times magnification of the surface of the Lyocell fabric after washing treated with 1 g / L polyacrylic acid emulsion under the process conditions of untreated and Example 2;

[0029] Figure 3SEM comparison diagram at 300x magnification of the surface of Lyocell fabric washed after being treated with 3 g / L polyacrylic acid emulsion under untreated and Example 2 process conditions;

[0030] Figure 4 SEM comparison diagram at 300x magnification of the surface of Lyocell fabric washed after being treated with 5 g / L polyacrylic acid emulsion under untreated and Example 2 process conditions;

[0031] Figure 5 Diagram of the bursting strength test of the Lyocell knitted fabric treated in Example 2 of the present invention;

[0032] Figure 6 Diagram of the swelling rate test of the fibers in the Lyocell knitted fabric treated in Example 2 of the invention in the wet state;

[0033] Figure 7 SEM diagram at 5000x magnification of the surface of the Lyocell knitted fabric treated in Example 2 of the present invention;

[0034] Figure 8 Comparison diagram of the whiteness test of the Lyocell fabric before and after treatment. Detailed implementation mode

[0035] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] In the description of the present invention, the term "including" means "including but not limited to". The terms first, second, third, etc. are used only as labels and do not impose numerical requirements or establish an order. The term "a plurality of" means "two or more".

[0037] As Figure 1 shown, a green fibrillation prevention finishing method for Lyocell fabric includes the following steps:

[0038] I. Cationic modification:

[0039] (1) Dissolve polydimethyldiallylammonium chloride in deionized water to prepare a cationic modification treatment solution with a concentration of 2-3%, and set aside;

[0040] (2) Transfer the cationic modification treatment solution to the dyeing vat of an infrared dyeing machine, and immerse the Lyocell fabric in the above treatment solution with a bath ratio of 1:15 - 1:25;

[0041] (3) Set the rotation speed of the infrared dyeing machine to 60 r / min, heat from 20°C at a rate of 3°C / min to 55 - 65°C, continue to run at 55 - 65°C for 25 - 35 min, and then cool to 40°C at a rate of 6°C / min;

[0042] (4) After completion, rinse thoroughly with water and dry at 60 °C to obtain a cation-modified Lyocell fabric;

[0043] II. Treatment with an anionic polymer emulsion:

[0044] (5) Prepare a polyacrylic acid emulsion with a concentration of 1 - 5 g / L for standby;

[0045] (6) Transfer the polyacrylic acid emulsion to the dyeing vat of an infrared dyeing machine, and immerse the cation-modified Lyocell fabric in the polyacrylic acid emulsion with a bath ratio of 1:15 - 1:25;

[0046] (7) Set the rotation speed of the infrared dyeing machine to 60 r / min, heat up from 20 °C at a rate of 3 °C / min to 55 - 65 °C, continue to run at 55 - 65 °C for 25 - 35 min, and then cool down to 40 °C at a rate of 6 °C / min;

[0047] III. Pre-drying and curing treatment:

[0048] (8) First pre-dry the Lyocell fabric treated in step (7) at 100 °C for 8 - 12 min, and then cure it at a high temperature of 140 - 160 °C for 4 - 6 min to obtain an anti-fibrillation Lyocell fabric.

[0049] The cationic modifier used in the present invention: polydimethyldiallylammonium chloride (PDADMAC) (solid content 40%), purchased from Shandong Yousuo Chemical Technology Co., Ltd.; anionic polymer emulsion: polyacrylic acid emulsion (PAA) (solid content: 45%), purchased from Shanghai Kangdun New Materials Co., Ltd.

[0050] In the finishing method of the present invention, in the cationic modification stage, a slower heating rate (3 °C / min) enables the polymer to be more evenly adsorbed onto the fiber surface. Appropriate temperature and time can promote the thermal movement of PDADMAC molecules. Too low a temperature will result in a low adsorption rate, while too high a temperature may cause PDADMAC degradation or damage to the structure of Lyocell fibers. Rapid cooling (6 °C / min) is beneficial for PDADMAC molecules to form a dense and stable cationic layer on the fiber surface. In the stage of treating with an anionic polymer emulsion, slow heating (3 °C / min) can promote the full extension of the molecular chains of PAA and PDADMAC, enhancing the electrostatic interaction between the two. 60 °C is close to the optimal reaction temperature of PDADMAC, which can accelerate the adsorption of PAA and PDADMAC while avoiding fiber damage. At high temperatures, the polymer chain segments are actively moving, which is conducive to the formation of a dense and uniformly charged composite film. Rapid cooling can prevent the molecular chains from retracting or rearranging, maintaining the high charge density and uniformity of the film. In the pre-drying and curing treatment stage, pre-drying at 100 °C can efficiently remove the residual moisture in the Lyocell fabric and Lyocell fibers, promote the dehydration condensation of the PAA-PDADMAC complex, and improve the anti-elution property of the film on the surface of Lyocell fibers.

[0051] The following specifically illustrates the present application through specific examples. The following examples are only partial examples of the present application and do not limit the present application.

[0052] Example 1:

[0053] A green finishing method for anti-fibrillation of Lyocell fabric, comprising the following steps:

[0054] I. Cationic modification:

[0055] (1) Dissolve polydimethyldiallylammonium chloride in deionized water to prepare a cationic modification treatment solution with a concentration of 2%, and set aside;

[0056] (2) Transfer the cationic modification treatment solution to the dyeing vat of an infrared dyeing machine, and immerse the Lyocell fabric in the above treatment solution with a liquor ratio of 1:15;

[0057] (3) Set the rotation speed of the infrared dyeing machine to 60 r / min, heat from 20 °C at a rate of 3 °C / min to 55 °C, continue to run at 55 °C for 35 min, and then cool to 40 °C at a rate of 6 °C / min;

[0058] (4) After completion, rinse with water and dry at 60 °C to obtain the cationically modified Lyocell fabric;

[0059] II. Treatment with an anionic polymer emulsion:

[0060] (5) Prepare a polyacrylic acid emulsion with a concentration of 1 g / L for standby;

[0061] (6) Transfer the polyacrylic acid emulsion to the dye vat of an infrared dyeing machine, and immerse the cation-modified Lyocell fabric in the polyacrylic acid emulsion with a bath ratio of 1:15;

[0062] (7) Set the rotation speed of the infrared dyeing machine to 60 r / min. Heat from 20 °C to 55 °C at a rate of 3 °C / min, continue to run at 55 °C for 35 min, and then cool to 40 °C at a rate of 6 °C / min;

[0063] III. Pre-drying and curing treatment:

[0064] (8) First pre-dry the Lyocell fabric treated in step (7) at 100 °C for 8 min, and then cure it at a high temperature of 140 °C for 6 min to obtain an anti-fibrillation Lyocell fabric.

[0065] The anti-fibrillation green finishing method for Lyocell fabric is characterized in that: in the above step (7), heat from 20 °C to 60 °C at a rate of 3 °C / min and continue to run at 60 °C for 30 min.

[0066] The anti-fibrillation green finishing method for Lyocell fabric is characterized in that: in the above step (8), the Lyocell fabric is first pre-dried at 100 °C for 10 min and then cured at a high temperature of 150 °C for 5 min.

[0067] Example 2:

[0068] An anti-fibrillation green finishing method for Lyocell fabric includes the following steps:

[0069] I. Cation modification:

[0070] (1) Dissolve polydimethyldiallylammonium chloride in deionized water to prepare a cationic modification treatment solution with a concentration of 2.5% for standby;

[0071] (2) Transfer the cationic modification treatment solution to the dye vat of an infrared dyeing machine, and immerse the Lyocell fabric in the above treatment solution with a bath ratio of 1:20;

[0072] (3) Set the rotation speed of the infrared dyeing machine to 60 r / min. Heat from 20 °C to 60 °C at a rate of 3 °C / min, continue to run at 60 °C for 30 min, and then cool to 40 °C at a rate of 6 °C / min;

[0073] (4) After completion, rinse it with water and dry it at 60 °C to obtain a cation-modified Lyocell fabric;

[0074] II. Anionic polymer emulsion treatment:

[0075] (5) Prepare a polyacrylic acid emulsion with a concentration of 5 g / L for standby.

[0076] (6) Transfer the polyacrylic acid emulsion to the dyeing vat of an infrared dyeing machine, and immerse the cation-modified Lyocell fabric in the polyacrylic acid emulsion with a liquor ratio of 1:20.

[0077] (7) Set the rotation speed of the infrared dyeing machine to 60 r / min, heat from 20 °C at a rate of 3 °C / min to 60 °C, continue to run at 60 °C for 30 min, and then cool to 40 °C at a rate of 6 °C / min.

[0078] III. Pre-drying and curing treatment:

[0079] (8) First pre-dry the Lyocell fabric treated in step (7) at 100 °C for 10 min, and then cure it at a high temperature of 150 °C for 5 min to obtain a fibrillation-proof Lyocell fabric.

[0080] A green finishing method for fibrillation-proof of Lyocell fabric, characterized in that: in the above step (8), the Lyocell fabric is first pre-dried at 100 °C for 10 min, and then cured at a high temperature of 150 °C for 5 min.

[0081] Example 3:

[0082] A green finishing method for fibrillation-proof of Lyocell fabric, comprising the following steps:

[0083] I. Cation modification:

[0084] (1) Dissolve polydimethyldiallylammonium chloride in deionized water to prepare a cationic modification treatment solution with a concentration of 3%, and keep it for standby.

[0085] (2) Transfer the cationic modification treatment solution to the dyeing vat of an infrared dyeing machine, and immerse the Lyocell fabric in the above treatment solution with a liquor ratio of 1:25.

[0086] (3) Set the rotation speed of the infrared dyeing machine to 60 r / min, heat from 20 °C at a rate of 3 °C / min to 65 °C, continue to run at 65 °C for 25 min, and then cool to 40 °C at a rate of 6 °C / min.

[0087] (4) After completion, rinse it with water and dry it at 60 °C to obtain a cation-modified Lyocell fabric.

[0088] II. Anionic polymer emulsion treatment:

[0089] (5) Prepare a polyacrylic acid emulsion with a concentration of 3 g / L for standby.

[0090] (6) Transfer the polyacrylic acid emulsion to the dye vat of an infrared dyeing machine, and immerse the cation-modified Lyocell fabric in the polyacrylic acid emulsion with a bath ratio of 1:25;

[0091] (7) Set the rotation speed of the infrared dyeing machine to 60 r / min, heat up from 20 °C at a rate of 3 °C / min to 65 °C, continue to run at 55 - 65 °C for 25 min, and then cool down to 40 °C at a rate of 6 °C / min;

[0092] III. Pre-drying and curing treatment:

[0093] (8) First pre-dry the Lyocell fabric processed in step (7) at 100 °C for 12 min, and then cure it at a high temperature of 160 °C for 4 min to obtain anti-fibrillation Lyocell fabric.

[0094] The test results of the anti-fibrillation performance of the Lyocell fabric treated by the anti-fibrillation green finishing method of the present invention are as follows:

[0095] Cut a 5 cm × 5 cm Lyocell knitted fabric. Put 50 steel balls evenly into 5 pure cotton woven fabric bags as co-washing objects and put them into the dye vat, add 100 mL of soap solution with a concentration of 2 g / L, heat up from room temperature to 71 °C in a SW-12A type washing fastness tester, pause the machine, put the sample into the dye vat, take it out after running at 71 °C for 45 min, wash it 3 times with room temperature water for 1 min each time, and dry it in a blast drying oven at 60 °C. This whole process is recorded as 1 time. Wash it 3 times, and leave a sample to observe the fibrillation situation of the Lyocell knitted fabric under a scanning electron microscope (Phenom pure, Holland).

[0096] As Figures 2 - 4 shown, when the concentration of the anionic polymer emulsion is 1 g / L and cured at 150 °C, local fibrillation appears on the fabric after washing, and the fibrillation range is smaller than that of the untreated fabric, showing an anti-fibrillation effect; when the concentration of the anionic polymer emulsion is 3 g / L and cured at 150 °C, fibrillation begins to occur on the surface of the fabric after washing, and the fibrillation range is smaller than that of the untreated fabric and the generated fibrils are shorter, showing a better anti-fibrillation effect; when the concentration of the anionic polymer emulsion is 5 g / L and cured at 150 °C, almost no fibrillation phenomenon occurs on the surface of the fabric after washing, showing an obvious contrast with the untreated fabric and having an obvious anti-fibrillation effect. Therefore, Example 2 of the present invention is the best example.

[0097] As Figure 5As shown, after testing, the bursting strength of the lyocell knitted fabric obtained by the green finishing method of the present invention is 713N, and the bursting strength of the PDADMAC-PAA-Lyocell knitted fabric is 764N. It can be seen that the strength of the lyocell knitted fabric after cationic modification and anionic polymer emulsion treatment is improved. The elongation at break of the PDADMAC-PAA-Lyocell knitted fabric is greater than that of the untreated lyocell knitted fabric, indicating that the lyocell knitted fabric treated with the cationic modifier and the anionic polymer emulsion requires more work to break. This shows that the lyocell knitted fabric after treatment has higher toughness. It can be proved that the process method of the present invention not only does not affect the strength loss of the lyocell fiber, but instead improves the strength and toughness of the lyocell fiber after finishing.

[0098] like Figure 6 As shown in the figure, it can be seen that the skin-core structure of lyocell fiber makes the fiber easily show a high swelling rate in a wet state. Among them, the swelling rate of untreated lyocell knitted fabric is 70.6%. After the cationic modification and anionic polymer emulsion treatment, a thin film is formed on the surface of the lyocell knitted fabric. This film has a certain hydrophobicity and can effectively prevent water molecules from penetrating into the fiber, thereby significantly reducing the swelling rate of the treated lyocell knitted fabric to 42%. This effectively improves the anti-fibrillation effect of lyocell fiber.

[0099] like Figure 7 As shown, from the electron microscope photograph of the treated lyocell knitted fabric magnified 5000 times, it can be seen that the finishing method of the present invention not only forms a uniform and continuous film on the fiber surface, but also forms an irregular and discontinuous film between adjacent lyocell fibers. In some positions (such as in the circle), a film that adheres to adjacent fibers is formed, and in some positions, no continuous film is formed.

[0100] As we all know, the common method for preventing the fibrillation of lyocell fibers is high-temperature crosslinking, that is, through chemical crosslinking, a specific crosslinking agent is used to react chemically with lyocell fibers to form chemical bonds between cellulose molecular chains, react with hydroxyl groups on lyocell fibers, and bond between fibers through molecular linking technology to form bridges between different cellulose molecular chains, connecting the originally relatively independent molecular chains together, thereby limiting the splitting of fibrils and achieving the effect of preventing and controlling fibrillation. Although crosslinking can achieve a good anti-fibrillation effect, it often leads to a serious loss of fiber strength. Because the crosslinking agent connects the cellulose molecular chains through chemical bonds to form a network structure, and too high a crosslinking density will make the fiber brittle and reduce its flexibility. When external forces act, the crosslinking points may become stress concentration points, causing the fibers to break more easily when stressed. In addition, high temperatures will accelerate the aging process of the fibers, making them more susceptible to wear and damage during use.

[0101] In the inventive concept of forming a film on the fiber surface and partially forming a film between fibers, the present invention has three advantages. First, since the film has a certain hydrophobicity, it can slow down the water absorption and swelling of the fibers. Compared with the untreated fibers, the swelling degree of the fibers is significantly reduced, the force between the fibrils is enhanced, and thus the fibril splitting is reduced. Second, the uniform and continuous film formed on the fiber surface can play a certain protective role on the fibers under the condition of external mechanical force, reduce the friction force, and thus further reduce the tendency of fibril peeling on the fiber surface. Third, the partially irregular and discontinuous film formed between the fibers also improves the strength of the Lyocell fabric to a certain extent. As described in the bursting strength test of Figure 5 , it is precisely due to the increase in the binding force between the fibers, which further proves that the strength and toughness of the Lyocell fibers are improved after the finishing of the present invention.

[0102] As Figure 8 shown, by comparison, it can be obtained that compared with the whiteness of 63.2% of the untreated Lyocell fabric, the whiteness of the Lyocell fabric obtained by the finishing method of the present invention is 61.2%. The change in the whiteness of the Lyocell fabric is not significant. Thus, it can be obtained that the green finishing method of the present invention effectively solves the problem of fabric discoloration caused by the by-products decomposed after heating in the traditional high-temperature cross-linking process.

[0103] In summary, compared with the traditional high-temperature cross-linking anti-fibrillation method, the present invention adopts the concept of adsorption film formation. In water, due to the ionization of polar groups such as hydroxyl groups on the surface of Lyocell fibers, they carry negative charges, while the quaternary ammonium groups in the cationic modifier PDADMAC carry positive charges, enabling it to be adsorbed on the Lyocell fibers through electrostatic attraction. After being modified by PDADMAC, the surface of the Lyocell fibers changes from negative to positive. Polyacrylic acid is a polymer containing a large number of carboxyl groups, and these carboxyl groups can be ionized in water to form negatively charged carboxylate ions, which are adsorbed onto the PDADMAC-modified Lyocell fibers through electrostatic attraction. Through high-temperature baking, the adsorbed polymer particles are melted and diffused to form a film covering the fiber surface. It reduces the lateral swelling and axial splitting of the fibers, thereby reducing the formation of nano-scale fibrils. The research is through electrostatic adsorption and the formation of discontinuous films on the fiber surface. The Lyocell knitted fabric with a low fibrillation tendency prepared by the method of electrostatic adsorption has a simpler process flow, less chemical consumption, and no formaldehyde release compared with the traditional anti-fibrillation process, and can be widely used in the preparation of green anti-fibril Lyocell knitted fabrics. The purpose of low-cost and formaldehyde-free Lyocell green anti-fibrillation is achieved.

[0104] Certainly, the above description is not a limitation of the present invention, nor is the present invention limited to the above examples. Any changes, modifications, additions, or substitutions made by those of ordinary skill in the art within the scope of the essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A green finishing method for preventing fibrillation of lyocell fabric, characterized in that: The steps include:

1. Cationic modification: (1) Dissolve polydimethyldiallylammonium chloride in deionized water to prepare a 2-3% cationic modified treatment solution for later use; (2) Transfer the cationic modified treatment liquid to the dyeing vat of the infrared dyeing machine, and immerse the Lyocell fabric in the above treatment liquid at a bath ratio of 1:15-1:25; (3) Set the speed of the infrared dyeing machine to 60r / min, raise the temperature from 20℃ to 55-65℃ at a rate of 3℃ / min, continue to run at 55-65℃ for 25-35min, and then cool down to 40℃ at a rate of 6℃ / min; (4) After completion, rinse with water and dry at 60° C. to obtain a cationic modified Lyocell fabric; 2. Anionic polymer emulsion treatment: (5) Prepare a polyacrylic acid emulsion with a concentration of 1-5 g / L for standby use; (6) Transfer the polyacrylic acid emulsion to the dyeing vat of the infrared dyeing machine, and immerse the cationic modified lyocell fabric in the polyacrylic acid emulsion at a bath ratio of 1:15-1:25; (7) Set the speed of the infrared dyeing machine to 60r / min, raise the temperature from 20°C to 55-65°C at a rate of 3°C / min, continue to operate at 55-65°C for 25-35min, and then cool down to 40°C at a rate of 6°C / min; 3. Pre-baking and baking treatment: (8) The lyocell fabric treated in step (7) is pre-baked at 100° C. for 8-12 min, and then baked at 140-160° C. for 4-6 min to obtain an anti-fibrillation lyocell fabric.

2. The green anti-fibrillation finishing method for lyocell fabric according to claim 1, characterized in that: In the cationic modification treatment solution of step (1), the concentration of polydimethyldiallylammonium chloride is 2.5%.

3. The green anti-fibrillation finishing method for lyocell fabric according to claim 1, characterized in that: In the step (2), the bath ratio of the cationic modified treatment liquid to the lyocell fabric is 1:

20.

4. The green anti-fibrillation finishing method for lyocell fabric according to claim 1, characterized in that: In the step (3), the temperature is raised from 20°C to 60°C at a rate of 3°C / min, and the temperature is continued to operate at 60°C for 30 minutes.

5. The green anti-fibrillation finishing method for lyocell fabric according to claim 1, characterized in that: In the step (5), the concentration of the polyacrylic acid emulsion is 3 g / L.

6. The green anti-fibrillation finishing method for lyocell fabric according to claim 1, characterized in that: In the step (6), the bath ratio of the polyacrylic acid emulsion to the cationically modified lyocell fabric is 1:

20.

7. The green anti-fibrillation finishing method for lyocell fabric according to claim 1, characterized in that: In the step (7), the temperature is raised from 20°C to 60°C at a rate of 3°C / min, and the temperature is continued to operate at 60°C for 30 minutes.

8. The green anti-fibrillation finishing method for lyocell fabric according to claim 1, characterized in that: In the step (8), the lyocell fabric is first pre-baked at 100° C. for 10 minutes, and then baked at 150° C. for 5 minutes.

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