A sizing agent for rayon and a method for preparing the same

Abstract

The application relates to a sizing agent for rayon and a preparation method thereof, which comprises the following components in mass fractions: 900-1100 parts of methyl acrylate, 100-140 parts of acrylic acid, 110-150 parts of methyl methacrylate, 340-380 parts of acrylonitrile, 330-340 parts of ethanol, 2.5-3 parts of mercaptan, 130-150 parts of sodium dodecyl benzene sulfonate, 1.5-2.5 parts of whiting, 280-300 parts of smoothing agent, 18-20 parts of antistatic agent, 13-17 parts of bactericide, and the balance of water; and further comprising a nano composite hydrogel, wherein the nano composite hydrogel comprises L-arginine, silicotungstic acid, acrylic acid and a modified montmorillonite system. The application has the effects of improving the flexibility and wear resistance of the sizing agent for rayon.

Description

Technical Field

[0001] This application relates to the field of textile sizing agents, and in particular to a sizing agent for rayon and a method for preparing the same. Background Technology

[0002] Sizing is a core process in textile processing. It can give fibers good cohesion, improve their breaking strength, abrasion resistance and weaving processability. It is a key technology to ensure textile production efficiency and the quality of finished fabrics.

[0003] Rayon (viscose fiber) has seen its application in high-end textiles continue to expand due to its excellent luster, moisture absorption, and skin-friendliness. However, rayon itself has inherent characteristics such as low wet strength, easy fuzzing due to friction, and insufficient rigidity. Compared with conventional natural fibers, it has more stringent specialized requirements for the compatibility of sizing agents and its overall performance.

[0004] Currently, the industry mostly uses traditional starch and PVA-based general-purpose sizing agents for rayon. These sizing agents form rigid films but lack flexibility, leading to brittleness, curling, and tangling of the rayon after sizing. This not only significantly reduces weaving efficiency but also easily causes rayon abrasion, pilling, and breakage, severely affecting the hand feel and quality stability of the finished fabric. Therefore, developing a rayon-specific sizing agent that combines excellent flexibility and abrasion resistance has become an urgent technical problem to be solved in this field. Summary of the Invention

[0005] To improve the flexibility and abrasion resistance of sizing agents, this application provides a sizing agent for rayon and a method for preparing the same.

[0006] In one aspect, this application provides a sizing agent for rayon.

[0007] A sizing agent for rayon, comprising the following components in parts by weight: Methyl acrylate 900-1100 parts, acrylic acid 100-140 parts, methyl methacrylate 110-150 parts, acrylonitrile 340-380 parts, ethanol 330-340 parts, thiol 2.5-3 parts, sodium dodecylbenzene sulfonate 130-150 parts, styrene 1.5-2.5 parts, smoothing agent 280-300 parts, antistatic agent 18-20 parts, bactericide 13-17 parts, balance is water; It also includes nanocomposite hydrogels, which comprise a system of L-arginine, silicotungstic acid, acrylic acid, and modified montmorillonite.

[0008] By adopting the above technical solution, the basic slurry components consist of methyl acrylate, methyl methacrylate, and acrylonitrile forming a copolymer system. Methyl acrylate provides flexible chain segments, while methyl methacrylate and acrylonitrile provide a rigid skeleton. The molecular weight is adjusted by thiols to form a flexible basic slurry skeleton. A nanocomposite hydrogel is also introduced into the system, in which L-arginine and silicotungstic acid form a reversible cross-linked network through electrostatic complexation. Polyacrylic acid segments run through the network, and modified montmorillonite is uniformly distributed as a nano-reinforcing phase. The flexible polyacrylic acid chains in the hydrogel form hydrogen bonds or physical entanglements with the acrylate segments in the basic slurry, giving the slurry film excellent bending compliance. At the same time, the rigid sheets of modified montmorillonite and silicotungstic acid form reinforcing regions, constructing a multi-level reinforcing structure in the slurry film, which significantly improves the wear resistance of the system.

[0009] Preferably, the raw materials for preparing the modified montmorillonite system include montmorillonite, ferrous chloride, ferric chloride, and octadecyltrimethylammonium bromide.

[0010] By adopting the above technical solution, montmorillonite has a two-dimensional lamellar structure, which can improve the overall friction loss resistance and bending resistance of the system. Ferrous chloride and ferric chloride, as iron sources, can generate iron(III) oxide in situ on montmorillonite to obtain a rigid wear-resistant phase. This phase, together with the montmorillonite lamellar structure, amplifies the wear resistance enhancement effect and further reduces the breakage rate in the rayon weaving process. Octadecyltrimethylammonium bromide, as a cationic organic intercalation modifier, can expand the spacing of montmorillonite, reduce surface polarity, and significantly improve the compatibility of montmorillonite with the water-based acrylate system and hydrogel network. This prevents montmorillonite from agglomerating and settling, thus ensuring its dispersibility in the slurry. Furthermore, the modified montmorillonite can be stably intercalated into the three-dimensional cross-linked network of the hydrogel, realizing the combination of a flexible network and a rigid wear-resistant phase.

[0011] Preferably, the modified montmorillonite is prepared by the following method: Montmorillonite was mixed with water and ultrasonically treated to obtain a montmorillonite dispersion. Ferric chloride hexahydrate and ferrous chloride tetrahydrate were added to water, heated and stirred, and then added to the montmorillonite dispersion. The system was adjusted to alkalinity and stirred continuously. After stirring, the mixture was washed, magnetically separated, collected, and dried to obtain montmorillonite composite iron(III) oxide. Montmorillonite composite iron(III) oxide was mixed with water, and then octadecyltrimethylammonium bromide was added. The mixture was heated, washed, magnetically separated, and finally dried to obtain modified montmorillonite.

[0012] By adopting the above technical solution, montmorillonite is initially exfoliated and dispersed after ultrasonication, providing sufficient binding sites for iron salt loading and reducing agglomeration during subsequent loading processes. Then, through co-precipitation, iron oxide nanoparticles are generated in situ on the surface of montmorillonite, so that the wear-resistant phase is uniformly loaded on the surface and between the layers of montmorillonite sheets, reducing the self-agglomeration of nanoparticles and endowing the modified montmorillonite with magnetic responsiveness, which facilitates magnetic separation and purification during the preparation process. Finally, organic intercalation modification is performed by octadecyltrimethylammonium bromide, which further optimizes the interfacial compatibility of montmorillonite on the basis of the already loaded wear-resistant phase, thereby improving the stability of the system.

[0013] Preferably, the mass ratio of montmorillonite, ferric chloride hexahydrate, and ferrous chloride tetrahydrate is 1:(0.6-0.7):0.2.

[0014] By adopting the above technical solution, and optimizing the mass ratio of montmorillonite, ferric chloride hexahydrate, and ferrous chloride tetrahydrate within the above range, the iron salt can completely generate uniformly dispersed iron oxide nanoparticles in situ on the surface and between the layers of montmorillonite, thus ensuring the wear resistance and dispersion stability of the modified montmorillonite.

[0015] Preferably, the mass ratio of the montmorillonite composite iron oxide to octadecyltrimethylammonium bromide is 1:(1.4-1.6).

[0016] By adopting the above technical solution, and optimizing the mass ratio between montmorillonite composite iron oxide and octadecyltrimethylammonium bromide within the specified range, octadecyltrimethylammonium bromide can fully intercalate into the montmorillonite interlayer, achieving organic modification of montmorillonite. This significantly improves its compatibility with acrylate slurry and hydrogel network, reduces the agglomeration and sedimentation of montmorillonite in the slurry, and ultimately ensures uniform dispersion of modified montmorillonite in the slurry system, thereby enhancing the overall stability of the system.

[0017] Preferably, the nanocomposite hydrogel is prepared by the following method: L-arginine was mixed with water and stirred to obtain an L-arginine solution. Silicotungstic acid and modified montmorillonite were added to the L-arginine solution and magnetically stirred. Then acrylic acid was added and stirring continued. After stirring, potassium persulfate was added and the mixture was sonicated to obtain a mixed solution. The mixed solution was heated to react and obtain a nanocomposite hydrogel.

[0018] By adopting the above technical solution, L-arginine and silicotungstic acid first form a stable dynamic coordination crosslinking network, and the modified montmorillonite is uniformly dispersed. Then, acrylic acid monomer is added, so that the monomer is fully dispersed in the pre-constructed dynamic crosslinking system, ensuring that the polyacrylic acid formed after polymerization has good flexibility and interpenetrates with the modified montmorillonite to form a stable three-dimensional network. Using potassium persulfate as an initiator, the free radical polymerization reaction of acrylic acid is mild and controllable, and the prepared system has good uniformity and stability.

[0019] Preferably, the mass ratio of acrylic acid, silicotungstic acid and L-arginine is 1.7:(3.6-3.9):1.

[0020] By adopting the above technical solution, the mass ratio of acrylic acid, silicotungstic acid and L-arginine is preferably within the above range. L-arginine and silicotungstic acid can form a stable cross-linking network, providing stress dissipation capability for the gel system, thereby improving the toughness of the slurry. Furthermore, the amount of acrylic acid monomer can make the flexible acrylic acid segments formed after polymerization interpenetrate with the coordination network, thereby further improving the flexibility of the system. The amount of silicotungstic acid and modified montmorillonite form a synergistic wear-resistant effect, further improving the overall stability of the system.

[0021] Preferably, the modified montmorillonite system comprises 1.8-3.4 wt% of the mass of acrylic acid. By adopting the above technical solution, the amount of modified montmorillonite used is preferably within the above range, so that the modified montmorillonite can be uniformly dispersed in the system. As a rigid physical crosslinking point, it can give full play to the wear resistance enhancement effect of the lamellar barrier and iron oxide, and balance the overall rigidity.

[0022] Preferably, the nanocomposite hydrogel accounts for 2-8 wt% of the total solid content of the slurry.

[0023] By adopting the above technical solution, and preferably within the above range, the nanocomposite hydrogel can fully exert its flexibility and wear resistance, significantly improving the wear resistance of the slurry.

[0024] Secondly, this application provides a method for preparing rayon sizing, which adopts the following technical solution: A method for preparing a rayon sizing agent includes the following steps: Methyl acrylate, acrylic acid, methyl methacrylate, acrylonitrile, ethanol, nanocomposite hydrogel, and thiol are mixed to obtain a mixture. Water and sodium dodecylbenzenesulfonate are added to the mixture into a reactor. Ammonium persulfate is mixed with water and added to the reactor. Tert-butyl hydrogen peroxide solution, sodium silicate solution, penetrant solution, and defoamer solution are added to the reactor sequentially and stirred to obtain an acidic slurry. The acidic slurry is pumped into a neutralization tank, stirred, and water and caustic soda are added for acid-base neutralization. Alcohol, smoothing agent, antistatic agent solution, and bactericide solution are added to the neutralization tank and neutralized and stirred to obtain a slurry for rayon.

[0025] In summary, this application includes at least one of the following beneficial technical effects: By synergistically combining the base slurry and the nanocomposite hydrogel, the acrylate and acrylonitrile in the base slurry construct a film-forming framework that combines rigidity and flexibility, while L-arginine and silicotungstic acid in the nanocomposite hydrogel form a dynamic cross-linking network. Modified montmorillonite is uniformly dispersed as a rigid reinforcing phase, so that the slurry film has both excellent bending flexibility and abrasion resistance, effectively solving the problems of easy curling and high filament breakage rate after sizing rayon. By in-situ loading of iron oxide and intercalation of quaternary ammonium salts to montmorillonite, efficient separation and purification can be achieved by utilizing magnetic responsiveness. At the same time, the interfacial compatibility between montmorillonite and water-based acrylate system and hydrogel network can be significantly improved by expanding the interlayer spacing and reducing the surface polarity. This ensures that the rigid reinforcing phase is uniformly dispersed in the slurry and gives full play to the synergistic reinforcing effect of lamellar barrier and nanoparticles. By optimizing the mass ratio of L-arginine, silicotungstic acid, and acrylic acid, as well as the amount of modified montmorillonite added, a stable dynamic coordination network and a flexible polyacrylic acid chain interpenetrating structure are formed inside the hydrogel. By introducing an appropriate proportion of nanocomposite hydrogel into the slurry, stress dissipation and toughness improvement are achieved while maintaining good flexibility of the slurry film, thus achieving the best balance between flexibility and wear resistance. Detailed Implementation

[0026] The present application will be further described in detail below with reference to the embodiments: Raw material description: All raw materials in the examples are commercially available; the defoamer is CS15 defoamer, the antistatic agent is antistatic agent P, the bactericide is 2-methylisothiazolinone / 5-chloro-2-methylisothiazolinone (CAS No.: 55965-84-9), and the smoothing agent is a mixture of CW smoothing agent and P22 smoothing agent in a mass ratio of 2:1. Example 1

[0027] Preparation of modified montmorillonite: 55.56 g of montmorillonite (CAS No.: 1318-93-0) was added to 5000 g of deionized water and sonicated for 30 min to obtain a montmorillonite dispersion. 33.33 g of ferric chloride hexahydrate and 11.11 g of ferrous chloride tetrahydrate were added to 2000 g of deionized water, heated to 65°C, and stirred at 600 rpm for 5 min. This mixture was then added to the montmorillonite dispersion, and the pH was adjusted to 10 using ammonia. The mixture was stirred at 65°C for 1 h. Finally, deionized water and acetic acid were used to further adjust the pH. The precipitate was washed five times with alternating ethanol and deionized water, and then collected by magnetic separation. It was dried at 60°C for 8 hours under vacuum to obtain montmorillonite composite iron oxide. 60g of the prepared montmorillonite composite iron oxide was dispersed in 5000g of deionized water, and 84g of octadecyltrimethylammonium bromide (CAS No.: 1120-02-1) was added while stirring at 300rpm. The temperature was raised to 70°C, and after 2 hours, the precipitate was washed five times with alternating ethanol and deionized water. Finally, modified montmorillonite was obtained by magnetic separation.

[0028] Preparation of nanocomposite hydrogels: 79.37 g of L-arginine (CAS No.: 74-79-3) was mixed with 3000 g of deionized water and magnetically stirred for 10 min to obtain an L-arginine solution. 285.71 g of silicotungstic acid (CAS No.: 12027-38-2) and modified montmorillonite were added to the L-arginine solution and magnetically stirred for 10 min. Then, 134.92 g of acrylic acid (CAS No.: 79-10-7) was added and magnetically stirred for another 10 min. After stirring, 6.5 g of potassium persulfate was added and magnetically stirred again for 5 min. Then, the mixture was sonicated for 30 s to obtain a mixed solution. The mixed solution was heated to 60 °C and polymerized for 6 h to obtain a nanocomposite hydrogel. The mass of the modified montmorillonite system added was 1.8 wt% of the mass of acrylic acid.

[0029] Preparation of sizing agents for rayon: 900g of methyl acrylate, 100g of acrylic acid, 110g of methyl methacrylate (CAS No.: 80-62-6), 330g of acrylonitrile (CAS No.: 107-13-1), 330g of ethanol, and nanocomposite hydrogel were sequentially added to a mixing tank. Then, 2.5g of thiol was added to the mixing tank, and the mixture was mixed for 20 minutes at room temperature and pressure to obtain a mixture. The mixture was then pumped into a reaction vessel, and subsequently, 6000g of deionized water and 130g of dodecyl sulfate were added. Sodium alkylbenzene sulfonate (CAS No.: 25155-30-0) was added to the reactor and stirred. 75g of ammonium persulfate was mixed with 40g of process water to obtain an ammonium persulfate solution, which was then added to the reactor. 1.5g of tert-butyl hydroperoxide (CAS No.: 75-91-2) was mixed with 78g of process water to obtain a tert-butyl hydroperoxide solution. 1.5g of styrax bleaching powder was mixed with 80g of industrial water to obtain a styrax bleaching solution. 18g of fatty alcohol polyoxyethylene ether penetrant was added. A penetrant solution was obtained by mixing 18g of defoamer with 100g of process water. The tert-butyl hydrogen peroxide solution, sodium hydroxide solution, penetrant solution, and defoamer solution prepared above were then sequentially added to a reaction vessel, and the mixture was stirred continuously for 5 hours to obtain an acidic slurry. The acidic slurry was then pumped into a neutralization tank, stirring was started, and 550g of process water was added to the neutralization tank. Then, 180g of caustic soda was pumped in, and another 550g of process water was added. Acid-base neutralization was performed to adjust the pH of the acidic slurry to 7.5. 18g of antistatic agent was mixed with 50g of deionized water to obtain an antistatic agent solution. 13g of bactericide was mixed with 30g of process water to obtain a bactericide solution. 550g of alcohol, 280g of smoothing agent, the antistatic agent solution and bactericide solution prepared above were added sequentially to the neutralization tank and stirred for 10 minutes to obtain a slurry for rayon. The added nanocomposite hydrogel accounted for 2wt% of the total solid content of the slurry. Example 2

[0030] Preparation of modified montmorillonite: 52.63 g of montmorillonite was added to 5000 g of deionized water and sonicated for 30 min to obtain a montmorillonite dispersion. 36.84 g of ferric chloride hexahydrate and 10.53 g of ferrous chloride tetrahydrate were added to 2000 g of deionized water, heated to 65 °C, and stirred at 600 rpm for 5 min. This mixture was then added to the montmorillonite dispersion, and the pH was adjusted to 10 using ammonia. The mixture was stirred at 65 °C for 1 h. Finally, deionized water and acetic acid were used to further adjust the pH. The precipitate was washed five times with alternating ethanol and deionized water, and then collected by magnetic separation. It was dried at 60°C for 8 hours under vacuum to obtain montmorillonite composite iron oxide. 60g of the montmorillonite composite iron oxide prepared above was dispersed in 5000g of deionized water, and 96g of octadecyltrimethylammonium bromide was added under stirring at 300rpm. The temperature was raised to 70°C, and after 2 hours, the precipitate was washed five times with alternating ethanol and deionized water. Finally, modified montmorillonite was obtained by magnetic separation.

[0031] Preparation of nanocomposite hydrogels: 75.76 g of L-arginine was mixed with 3000 g of deionized water and magnetically stirred for 10 min to obtain an L-arginine solution. 295.45 g of silicotungstic acid and modified montmorillonite were added to the L-arginine solution and magnetically stirred for 10 min. Then, 128.79 g of acrylic acid was added and magnetically stirred for another 10 min. After stirring, 6.5 g of potassium persulfate was added and magnetically stirred again for 5 min. The mixture was then sonicated for 30 s to obtain a mixed solution. The mixed solution was heated to 60 °C and polymerized for 6 h to obtain a nanocomposite hydrogel. The mass of the modified montmorillonite system added was 3.4 wt% of the mass of acrylic acid.

[0032] Preparation of sizing agents for rayon: 1100g of methyl acrylate, 140g of acrylic acid, 150g of methyl methacrylate, 380g of acrylonitrile, 340g of ethanol, and nanocomposite hydrogel were sequentially added to a mixing tank. Then, 3.5g of thiol was added to the mixing tank, and the mixture was mixed for 20 minutes at room temperature and pressure to obtain a mixture. The mixture was then pumped into a reaction vessel, and subsequently, 6000g of deionized water and 150g of sodium dodecylbenzenesulfonate were added to the reaction vessel. Stirring is performed; 80g of ammonium persulfate is mixed with 40g of process water to obtain an ammonium persulfate solution, which is then added to the reactor; 2.5g of tert-butyl hydrogen peroxide is mixed with 78g of process water to obtain a tert-butyl hydrogen peroxide solution; 2.5g of sodium bicarbonate is mixed with 80g of industrial water to obtain a sodium bicarbonate solution; 24g of fatty alcohol polyoxyethylene ether penetrant is mixed with 42g of industrial water to obtain a penetrant solution; 22g of defoamer is mixed with 10g of process water to obtain a penetrant solution. 0g of process water was mixed to obtain an antifoaming solution. The tert-butyl hydrogen peroxide solution, styrax solution, penetrant solution, and antifoaming solution prepared above were added sequentially to the reactor, and then stirred continuously for 5 hours to obtain an acidic slurry. The acidic slurry was pumped into a neutralization tank, stirring was started, and 550g of process water was added to the neutralization tank. Then, 220g of caustic soda was pumped in, and 550g of process water was added to neutralize the acid and adjust the pH of the acidic slurry to 7.5. 20g of antistatic agent was mixed with 50g of deionized water to obtain an antistatic agent solution. 17g of bactericide was mixed with 30g of process water to obtain a bactericide solution. 550g of alcohol, 320g of smoothing agent, the antistatic agent solution prepared above, and the bactericide solution were added sequentially to the neutralization tank, and neutralized and stirred for 10 minutes to obtain a slurry for rayon. The added nanocomposite hydrogel accounted for 8wt% of the total solid content of the slurry. Example 3

[0033] Preparation of modified montmorillonite: 54.05 g of montmorillonite was added to 5000 g of deionized water and sonicated for 30 min to obtain a montmorillonite dispersion. 35.14 g of ferric chloride hexahydrate and 10.81 g of ferrous chloride tetrahydrate were added to 2000 g of deionized water, heated to 65 °C, and stirred at 600 rpm for 5 min. This mixture was then added to the montmorillonite dispersion, and the pH was adjusted to 10 using ammonia. The mixture was then stirred at 65 °C for 1 h. Finally, deionized water and acetic acid were used to further adjust the pH. The precipitate was washed five times with alternating ethanol and deionized water, and then collected by magnetic separation. It was dried at 60°C for 8 hours under vacuum to obtain montmorillonite composite iron oxide. 60g of the montmorillonite composite iron oxide prepared above was dispersed in 5000g of deionized water, and 90g of octadecyltrimethylammonium bromide was added under stirring at 300rpm. The temperature was raised to 70°C, and after 2 hours, the precipitate was washed five times with alternating ethanol and deionized water. Finally, modified montmorillonite was obtained by magnetic separation.

[0034] Preparation of nanocomposite hydrogels: 77.52 g of L-arginine was mixed with 3000 g of deionized water and magnetically stirred for 10 min to obtain an L-arginine solution. 290.7 g of silicotungstic acid and modified montmorillonite were added to the L-arginine solution and magnetically stirred for 10 min. Then, 131.78 g of acrylic acid was added and magnetically stirred for another 10 min. After stirring, 6.5 g of potassium persulfate was added and magnetically stirred again for 5 min. The mixture was then sonicated for 30 s to obtain a mixed solution. The mixed solution was heated to 60 °C and polymerized for 6 h to obtain a nanocomposite hydrogel. The mass of the modified montmorillonite system added was 3.4 wt% of the mass of acrylic acid.

[0035] Preparation of sizing agents for rayon: 1000g of methyl acrylate, 120g of acrylic acid, 130g of methyl methacrylate, 360g of acrylonitrile, 335g of ethanol, and nanocomposite hydrogel were sequentially added to a mixing tank. Then, 3g of thiol was added to the mixing tank, and the mixture was mixed for 20 minutes at room temperature and pressure to obtain a mixture. The mixture was then pumped into a reaction vessel. Subsequently, 6000g of deionized water and 140g of sodium dodecylbenzenesulfonate were added to the reaction vessel and stirred. 78g of ammonium persulfate was mixed with 40g of process water to obtain an ammonium persulfate solution, which was then added to the reaction vessel. 2g of tert-butyl hydrogen peroxide was mixed with 78g of process water to obtain a tert-butyl hydrogen peroxide solution. 2g of sodium chloroform powder was mixed with 80g of industrial water to obtain a sodium chloroform powder solution. 21g of fatty alcohol polyoxyethylene ether penetrant was mixed with 42g of industrial water to obtain a penetrant solution. 20g of defoamer was mixed with 100g of... Process water is mixed to obtain an antifoaming solution. The tert-butyl hydrogen peroxide solution, styrax solution, penetrant solution, and antifoaming solution prepared above are added sequentially to a reaction vessel, and then stirred continuously for 5 hours to obtain an acidic slurry. The acidic slurry is pumped into a neutralization tank, stirring is started, and 550g of process water is added to the neutralization tank. Then, 200g of caustic soda is pumped in, and another 550g of process water is added to neutralize the acid and adjust the pH of the acidic slurry to 7.5. 20g of antistatic agent is mixed with 50g of deionized water to obtain an antistatic agent solution. 15g of bactericide is mixed with 30g of process water to obtain a bactericide solution. 550g of alcohol, 300g of smoothing agent, the antistatic agent solution prepared above, and the bactericide solution are added sequentially to the neutralization tank, and neutralized and stirred for 10 minutes to obtain a slurry for rayon. The added nanocomposite hydrogel accounts for 2wt% of the total solid content of the slurry. Example 4

[0036] Example 4 is based on Example 3. In the preparation of montmorillonite composite iron oxide in Example 4, 58.82g of montmorillonite, 29.41g of ferric chloride hexahydrate, and 11.77g of ferrous chloride tetrahydrate were used. Example 5

[0037] Example 5 is based on Example 3. In the preparation of montmorillonite composite iron oxide in Example 5, 50g of montmorillonite, 40g of ferric chloride hexahydrate, and 10g of ferrous chloride tetrahydrate were used. Example 6

[0038] Example 6 is based on Example 3. In Example 6, 75g of octadecyltrimethylammonium bromide was used in the preparation of the modified montmorillonite system. Example 7

[0039] Example 7 is based on Example 3. In Example 7, 105g of octadecyltrimethylammonium bromide was used in the preparation of the modified montmorillonite system. Example 8

[0040] Example 8 is based on Example 3. In Example 8, when preparing the modified montmorillonite system, the montmorillonite composite iron oxide is replaced with ordinary montmorillonite. Example 9

[0041] Example 9 is based on Example 3. In Example 9, when preparing the modified montmorillonite system, the montmorillonite composite iron oxide is replaced with a physical mixture of montmorillonite and iron oxide at a mass ratio of 1:1. Example 10

[0042] Example 10 is based on Example 3. In the preparation of the nanocomposite hydrogel in Example 10, the amount of acrylic acid used was 139.34g, silicotungstic acid was 278.69g, and L-arginine was 81.97g. Example 11

[0043] Example 11 is based on Example 3. In the preparation of the nanocomposite hydrogel in Example 11, 125g of acrylic acid, 301.47g of silicotungstic acid, and 73.53g of L-arginine were used. Example 12

[0044] Example 12 is based on Example 3. In Example 12, when preparing the nanocomposite hydrogel, the amount of modified montmorillonite system added is 1.3 wt% of the mass of acrylic acid. Example 13

[0045] Example 13 is based on Example 3. In Example 13, the amount of modified montmorillonite system added during the preparation of nanocomposite hydrogel is 3.9 wt% of the mass of acrylic acid. Example 14

[0046] Example 14 is based on Example 3. In Example 14, L-arginine was not added when preparing the nanocomposite hydrogel. Example 15

[0047] Example 15 is based on Example 3. In Example 15, no modified montmorillonite composite system was added when preparing the nanocomposite hydrogel. Example 16

[0048] Example 16 is based on Example 3. In Example 16, no silicotungstic acid was added when preparing the nanocomposite hydrogel. Example 17

[0049] Example 17 is based on Example 3. In Example 17, L-arginine was replaced with chitosan when preparing the nanocomposite hydrogel.

[0050] Comparative Example 1 Comparative Example 1 is based on Example 3. In Comparative Example 1, the modified montmorillonite system was replaced with ordinary montmorillonite when preparing the nanocomposite hydrogel.

[0051] Comparative Example 2 Comparative Example 2 is based on Example 3. In Comparative Example 2, no nanocomposite hydrogel was added when making the sizing agent for rayon.

[0052] Performance testing Samples from Examples 1-17 and Comparative Examples 1-2 were taken, using the same batch and specification of rayon yarn. The sizing concentration and solid content of the sizing in each comparative group were adjusted to 15%. After sizing, the yarn was equilibrated in a constant temperature and humidity chamber (temperature 20±2℃, humidity 65±5%) for 24 hours before testing. (1) Compliance Using GB / T 18318.1-2009 as the testing reference, the flexibility of the samples was tested. Each sample was tested 3 times, and the average value was taken. The test results were filled in Table 1. (2) Abrasion resistance Using GB / T 21196.2-2007 as the testing reference, the abrasion resistance of the samples was tested. Each sample was tested 3 times, and the average value was taken. The test results were recorded in Table 1.

[0053] Table 1. Performance test results of samples from Examples 1-17 and Comparative Examples 1-2

[0054] As shown in Table 1, the bending stiffness of Examples 1-3 is 7.5 mN·cm or higher, and the number of abrasion cycles is 500 or higher, indicating that the rayon sizing material prepared in this application has good flexibility and abrasion resistance.

[0055] In Examples 4 and 5, the mass ratios of montmorillonite, ferric chloride hexahydrate, and ferrous chloride tetrahydrate in the preparation of montmorillonite composite iron oxide were not within the range specified in this application. When ferric chloride hexahydrate was insufficient, the amount of wear-resistant iron oxide phase generated in situ was too small, making it difficult to form an effective composite wear-resistant system with montmorillonite, resulting in a decrease in the wear resistance of the slurry. When ferric chloride hexahydrate was excessive, the generated iron oxide self-aggregated, forming micron-sized rigid particles. The agglomerated particles would destroy the dynamic cross-linking network of the hydrogel, resulting in a significant decrease in flexibility.

[0056] In Examples 6 and 7, the mass ratio between octadecyltrimethylammonium bromide and montmorillonite composite iron oxide was not within the range specified in this application when preparing modified montmorillonite. When octadecyltrimethylammonium bromide was insufficient, the modification of montmorillonite was inadequate, the interlayer distance was difficult to effectively expand, and it could not intercalate into the hydrogel network. Instead, it agglomerated and settled in the system, making it difficult to exert its wear-resistant reinforcing effect, resulting in a decrease in the performance of the slurry. When octadecyltrimethylammonium bromide was excessive, it would undergo a charge neutralization reaction with the anionic emulsifier in the system, thereby destroying the stability of the acrylate emulsion, resulting in poor film-forming properties and poor water resistance, which affected the overall performance.

[0057] In Example 8, when preparing the modified montmorillonite system, the montmorillonite composite iron oxide was replaced with ordinary montmorillonite. The unmodified montmorillonite was indeed a rigid wear-resistant phase. The wear resistance enhancement was limited by the lamellar barrier effect of montmorillonite alone. Moreover, the unmodified montmorillonite had poor compatibility and stability in the system.

[0058] In Example 9, when preparing the modified montmorillonite system, montmorillonite and iron oxide were physically mixed. However, physical mixing makes it difficult to achieve the synergistic effect of in-situ loading. Iron oxide agglomerates severely in the system and forms large particles, leading to stress concentration in the system. Furthermore, the binding between the physically mixed iron oxide and montmorillonite decreases, resulting in decreased stability. Therefore, the overall performance of the system is reduced.

[0059] In Examples 10 and 11, the mass ratios of acrylic acid, silicotungstic acid, and L-arginine in the preparation of nanocomposite hydrogels were not within the range specified in this application. When silicotungstic acid was insufficient, L-arginine could not form a cross-linked network of sufficient density, resulting in decreased stress dissipation capacity and performance. When silicotungstic acid was excessive, it would lead to an excessively high density of dynamic cross-linked network and excessive rigidity. Furthermore, free silicotungstic acid would disrupt the continuity of the slurry and reduce its stability.

[0060] In Examples 12 and 13, the amount of modified montmorillonite used in the preparation of nanocomposite hydrogels was not within the range specified in this application. When the amount of modified montmorillonite was insufficient, the amount of rigid and wear-resistant phase added to the system was insufficient, making it difficult to form sufficient physical cross-linking points and wear-resistant support in the hydrogel network. When the amount of modified montmorillonite was excessive, the proportion of rigid phase in the hydrogel network was too high, the overall rigidity increased and the flexibility decreased, and the excessive montmorillonite agglomerated secondary, resulting in decreased stability.

[0061] In Example 14, no L-arginine was added when preparing the nanocomposite hydrogel, making it difficult to form a dynamic cross-linked network. It was only a polyacrylic acid gel, and its flexibility and abrasion resistance were reduced.

[0062] In Example 15, when preparing the nanocomposite hydrogel, no modified montmorillonite composite system was added, and the wear resistance performance was severely reduced due to the reliance on the wear-resistant effect of silicotungstic acid alone.

[0063] In Example 16, no silicotungstic acid was added during the preparation of the nanocomposite hydrogel, making it difficult to form a dynamic cross-linked network. The hydrogel was simply a physical mixture of polyacrylic acid and modified montmorillonite, resulting in a decrease in both flexibility and abrasion resistance.

[0064] In Example 17, L-arginine was replaced with chitosan. Chitosan is a cationic polymer, which neutralizes the charge of the anionic emulsifier in the system, causing the emulsion to break down and its stability to decrease. In addition, the chitosan molecular chain is too rigid, resulting in a decrease in the flexibility of the network formed.

[0065] In Comparative Example 1, when preparing nanocomposite hydrogels, the modified montmorillonite was replaced with ordinary montmorillonite. The unmodified montmorillonite had a small interlayer spacing, strong surface hydrophilicity, poor compatibility with acrylate monomers and hydrogel networks, and would destroy the structural integrity of the hydrogel, resulting in a decrease in the system's flexibility and wear resistance.

[0066] In Comparative Example 2, when the nanocomposite hydrogel was replaced with a modified montmorillonite system during slurry preparation, the lack of a flexible network made it difficult to effectively buffer the rigidity of the base slurry itself, resulting in a hard slurry film with high bending resistance. Furthermore, the modified montmorillonite was difficult to disperse evenly in the body, and some montmorillonite agglomerated, affecting the overall stability of the system.

[0067] This specific embodiment is merely an explanation of this application and is not intended to limit it. Based on the above description, those skilled in the art can make various changes and modifications without departing from the technical concept of this application. The technical scope of this application is not limited to the contents of the specification but must be determined according to the scope of the claims.

Claims

1. A sizing agent for rayon, characterized in that: The components include the following parts by mass: Methyl acrylate 900-1100 parts, acrylic acid 100-140 parts, methyl methacrylate 110-150 parts, acrylonitrile 340-380 parts, ethanol 330-340 parts, thiol 2.5-3 parts, sodium dodecylbenzene sulfonate 130-150 parts, ammonium persulfate 75-80 parts, tert-butyl hydroperoxide 1.5-2.5 parts, penetrant 18-24 parts, defoamer 18-22 parts, bleaching agent 1.5-2.5 parts, smoothing agent 280-300 parts, antistatic agent 18-20 parts, bactericide 13-17 parts, balance water; It also includes nanocomposite hydrogels, which comprise a system of L-arginine, silicotungstic acid, acrylic acid, and modified montmorillonite.

2. The sizing agent for rayon according to claim 1, characterized in that: The raw materials for preparing the modified montmorillonite system include montmorillonite, ferrous chloride, ferric chloride, and octadecyltrimethylammonium bromide.

3. The sizing agent for rayon according to claim 2, characterized in that: The modified montmorillonite was prepared using the following method: Montmorillonite was mixed with water and ultrasonically treated to obtain a montmorillonite dispersion. Ferric chloride hexahydrate and ferrous chloride tetrahydrate were added to water, heated and stirred, and then added to the montmorillonite dispersion. The system was adjusted to alkalinity and stirred continuously. After stirring, the mixture was washed, magnetically separated, collected, and dried to obtain montmorillonite composite iron(III) oxide. Montmorillonite composite iron(III) oxide was mixed with water, and then octadecyltrimethylammonium bromide was added. The mixture was heated, washed, magnetically separated, and finally dried to obtain modified montmorillonite.

4. The sizing agent for rayon according to claim 3, characterized in that: The mass ratio of montmorillonite, ferric chloride hexahydrate, and ferrous chloride tetrahydrate is 1:(0.6-0.7):0.

2.

5. The sizing agent for rayon according to claim 3, characterized in that: The mass ratio of the montmorillonite composite iron oxide to octadecyltrimethylammonium bromide is 1:(1.4-1.6).

6. The sizing agent for rayon according to claim 1, characterized in that: The nanocomposite hydrogel was prepared using the following method: L-arginine was mixed with water and stirred to obtain an L-arginine solution. Silicotungstic acid and modified montmorillonite were added to the L-arginine solution and magnetically stirred. Then acrylic acid was added and stirring continued. After stirring, potassium persulfate was added and the mixture was sonicated to obtain a mixed solution. The mixed solution was heated to react and obtain a nanocomposite hydrogel.

7. A sizing agent for rayon according to claim 6, characterized in that: The mass ratio of acrylic acid, silicotungstic acid and L-arginine is 1.7:(3.6-3.9):

1.

8. A sizing agent for rayon according to claim 6, characterized in that: The modified montmorillonite system has a mass of 1.8-3.4 wt% of acrylic acid.

9. A sizing agent for rayon according to claim 1, characterized in that: The nanocomposite hydrogel accounts for 2-8 wt% of the total solid content of the slurry.

10. A method for preparing a sizing agent for rayon according to any one of claims 1-9, characterized in that: Includes the following steps: Methyl acrylate, acrylic acid, methyl methacrylate, acrylonitrile, ethanol, nanocomposite hydrogel, and thiol are mixed to obtain a mixture. Water and sodium dodecylbenzenesulfonate are added to the mixture into a reactor. Ammonium persulfate is mixed with water and added to the reactor. Tert-butyl hydrogen peroxide solution, sodium silicate solution, penetrant solution, and defoamer solution are added to the reactor sequentially and stirred to obtain an acidic slurry. The acidic slurry is pumped into a neutralization tank, stirred, and water and caustic soda are added for acid-base neutralization. Alcohol, smoothing agent, antistatic agent solution, and bactericide solution are added to the neutralization tank and neutralized and stirred to obtain a slurry for rayon.

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