Low-shrinkage viscose filament yarn and process for its production

Abstract

The application discloses a low-shrinkage viscose filament and a preparation method thereof, and comprises the following steps: (1) preparing viscose: impregnating, pressing, and crushing pulp in lye to obtain alkali cellulose, then aging, cooling, yellowing, grinding dissolving, defoaming, filtering, and ripening the alkali cellulose, and adding metal sulfate and a solidifying agent in the ripening process to prepare the viscose; (2) spinning: the viscose is processed by a metering pump, a filter, a spinneret, a coagulation bath, a drafting disc, a hot roller, and a deacidification roller to be spun. The application promotes the improvement of the crystal nucleus generation rate of the viscose in the spinning process as a whole by adding metal sulfate and a solidifying agent in the viscose preparation process and adjusting the concentration of the coagulation bath and the temperature of the hot roller in the spinning process, so that the crystal nucleus arrangement is more compact, the proportion of the crystal region is larger compared with the amorphous region, the overall densification of the fiber is improved, the stress is reduced, and the shrinkage rate after the fiber meets hot water is reduced.

Description

Technical Field

[0001] This invention relates to the textile field, and more specifically, to a low-shrinkage viscose filament and its preparation method. Background Technology

[0002] Viscose filament generally refers to regenerated fiber fabrics. Regenerated fibers, also known as rayon, are made by dissolving and spinning cellulose from cotton linters, wood, and other materials. Viscose filament is a type of viscose fiber, also called rayon, kerosene, or ice silk. Among the 12 major textile fibers, viscose fiber has the moisture content that best meets the physiological requirements of human skin, possessing properties such as smoothness, coolness, breathability, antistatic properties, and vibrant dyeing colors.

[0003] Currently, regardless of whether viscose filament is produced by continuous spinning or centrifugal spinning, the finished product will experience significant shrinkage when exposed to boiling water. This is because the molecular formula of viscose fiber is C6H. 10 O5 has three hydroxyl groups in its molecular chain, resulting in relatively weak intermolecular forces. However, its core-sheath structure creates a large area of ​​amorphous structure within the fiber. This amorphous region has low densification and relatively high internal stress. Although the tendency towards crystallization is improved through drawing during spinning, the inhomogeneity between the crystalline and amorphous regions within the fiber ultimately leads to significant internal stress. During subsequent weaving and dyeing processes, the stress is released upon activation by boiling water, ultimately causing fiber shrinkage and affecting the smoothness and weaving yield of the finished fabric.

[0004] How to reduce the shrinkage rate of viscose filament and improve the finished product quality of viscose filament is an urgent problem to be solved.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a method for preparing viscose filaments with low shrinkage. By taking measures such as adding metal sulfate salts and curing agents during the viscose preparation process, and adjusting the concentration of the coagulation bath and the temperature of the hot rollers during the spinning process, the overall rate of crystal nucleation of viscose during spinning is promoted, the crystal nuclei are arranged more tightly, the proportion of crystalline regions is larger than that of amorphous regions, the overall fiber density is improved, the stress is reduced, and the shrinkage rate after encountering hot water is reduced.

[0007] To solve the above-mentioned technical problems, the basic concept of the technical solution adopted by the present invention is as follows:

[0008] A method for preparing low-shrinkage viscose filaments includes the following steps:

[0009] (1) Preparation of viscose: The pulp is soaked, pressed and crushed in alkaline solution to obtain alkali cellulose. Then it is aged, cooled, xanthated, ground and dissolved, defoamed, filtered and matured. During the maturation process, metal sulfate salt and curing agent are added to obtain viscose.

[0010] (2) Spinning: Viscose is spun after being processed by metering pump, filter, spinneret, coagulation bath, drawing plate, hot roller and deacidification roller.

[0011] Furthermore, the sulfate metal salt is selected from one or more of potassium sulfate, zinc sulfate, and aluminum sulfate;

[0012] Preferably, the sulfate metal salt is potassium sulfate.

[0013] In the above scheme, potassium sulfate is preferred as the metal sulfate salt because the aqueous solution of potassium sulfate is neutral. During the solidification and molding process of the adhesive, the presence of potassium sulfate makes it easy to form crystal nuclei around the potassium sulfate, which can effectively increase the generation rate of crystal nuclei inside the fiber and reduce the proportion of amorphous regions.

[0014] Furthermore, the curing agent is a water-based polyurethane resin.

[0015] In the above scheme, the waterborne polyurethane resin undergoes dehydration and salting during the spinning process, forming a tiny sponge-like network inside the fiber. This network solidifies to form the internal framework of the fiber, which serves to fix the internal structure and size of the fiber.

[0016] Furthermore, the mass of the cellulose fiber in the adhesive is 5% to 6.5% of the adhesive mass, preferably 6%.

[0017] In the above schemes, compared with the existing technology where the methyl cellulose content in the adhesive mostly exceeds 8%, the present invention reduces the methyl cellulose content in the adhesive, thereby increasing the concentration difference between the adhesive and the coagulation bath, increasing the dual diffusion rate of the adhesive and the coagulation bath, and making the adhesive react more completely during the preparation process.

[0018] Furthermore, the mass of the metal sulfate salt is 0.5% to 3% of the mass of the cellulose sulfate, preferably 0.5% to 1%.

[0019] Furthermore, the curing agent has a mass of 1% to 10% of the mass of the fiber methyl methacrylate, preferably 2% to 3.5%.

[0020] Furthermore, the coagulation bath is a mixture of sulfuric acid, zinc sulfate, and sodium sulfate, and the concentration of sulfuric acid in the coagulation bath is 90 g / L to 100 g / L.

[0021] The concentration of zinc sulfate in the coagulation bath is 10 g / L to 13 g / L; the concentration of sodium sulfate is 250 g / L to 300 g / L.

[0022] In the above scheme, adjusting and reducing the concentration of sulfuric acid in the coagulation bath is to prevent the skin from forming too quickly during the fiber forming process, resulting in excessively high density and making subsequent coagulation bath diffusion difficult.

[0023] Furthermore, the temperature of the hot roller is controlled at 70℃~90℃, preferably 70℃~75℃.

[0024] In the above scheme, in order to further improve the fiber forming conditions, the existing room temperature coagulation roller is replaced with a hot roller, and the forming conditions are further compensated by increasing the temperature.

[0025] Furthermore, the spinning speed during the spinning process is 45m / min to 65m / min, preferably 45m / min to 50m / min.

[0026] In the above scheme, the spinning speed during the spinning process is controlled within the above range so that the fiber is formed more fully and the crystallinity of the fiber can be further improved.

[0027] A low-shrinkage viscose filament is prepared by the method described above, wherein the shrinkage rate of the viscose filament is less than 1%.

[0028] By adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0029] This invention provides a method for preparing viscose filaments with low shrinkage. By adding metal sulfate salts during the curing process, the generation rate of crystal nuclei inside the fiber can be effectively increased, reducing the proportion of amorphous regions. By adding a curing agent during the curing process, a tiny sponge-like network is formed inside the fiber, which is then cured to form the internal framework structure of the fiber, fixing the internal structure and size of the fiber. This improves the overall density and internal compactness of the fiber, and enhances the fiber's resistance to deformation.

[0030] This invention increases the concentration difference between the adhesive and the coagulation bath by adjusting and reducing the content of cellulose in the adhesive, thereby increasing the dual diffusion rate of the adhesive and the coagulation bath.

[0031] This invention utilizes a low coagulation bath concentration to reduce the intensity of the reaction in the nascent filaments, and in the subsequent coagulation and molding process, it uses hot rollers to increase the temperature for compensation, making the internal structure of the fiber more uniform and dense.

[0032] This invention promotes the overall increase in the crystal nucleation rate of viscose during spinning by adding metal sulfate salts and curing agents during viscose preparation, and adjusting the concentration of the coagulation bath and the temperature of the hot rollers during spinning. This results in a more compact arrangement of crystal nuclei, a larger proportion of crystalline regions compared to amorphous regions, increased overall fiber density, reduced stress, and reduced shrinkage when exposed to hot water.

[0033] This invention significantly improves the characteristic of viscose filaments that shrink drastically when exposed to hot water, greatly enhancing the dimensional stability of the fiber itself. Furthermore, it has minimal impact on fiber strength and elongation, meeting the physical performance requirements of downstream manufacturing. Downstream fabrics, after high-temperature dyeing and finishing, exhibit minimal dimensional changes and a smooth finish. Compared to fabrics made from ordinary viscose fibers, they offer a significantly different style, making them suitable not only for lining applications but also for enhancing the smoothness of fabrics against the skin due to their low shrinkage, providing a unique sense of comfort. Simultaneously, the low shrinkage rate results in less shrinkage during weaving and dyeing, leading to higher finished product yields and effectively increasing profit margins across the industry chain.

[0034] The present invention provides a method for preparing low-shrinkage viscose filaments, which is simple, easy to operate, low in cost, and has broad application prospects.

[0035] The present invention also provides a low-shrinkage viscose filament, which has good dimensional stability, smooth fabric surface, uniform yarn evenness, and low shrinkage in subsequent dyeing and finishing, resulting in high manufacturing yield and improving the production efficiency of downstream industrial chains. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention are described clearly and completely below with reference to some embodiments. Those skilled in the art will understand that the following embodiments are only used to explain the technical principles of this invention and are not intended to limit the scope of protection of this invention. For example, although this application describes the steps of the method of this invention in a specific order, these orders are not restrictive. Those skilled in the art can perform the steps in different orders without departing from the basic principles of this invention.

[0037] Example 1

[0038] (1) Preparation of viscose: Cotton, wood, and bamboo pulps are impregnated, pressed, and crushed in an alkaline solution to obtain alkali cellulose; then aged, cooled, and subjected to xanthation reaction with carbon disulfide to transform the solid into a viscous liquid; then physically ground and dissolved, followed by degassing and multiple filtrations to remove bubbles and impurities, and finally matured to form viscose suitable for spinning. The maturation process is carried out in a maturation tank. After injecting 20 kg of viscose into the maturation tank, 9.6 g of potassium sulfate and 42 g of water-based polyurethane resin are added simultaneously, and the mixture is stirred for 27 to 30 hours using the stirrer of the maturation tank to ensure that the added substances are evenly dispersed in the viscose. Finally, the mixture is discharged for spinning. During the preparation process, the content of methyl cellulose in the viscose is controlled to be 1.2 kg.

[0039] (2) Spinning: The prepared viscose is pumped into the spindle filtration device by the metering pump of the spinning machine. After filtration, the viscose is conveyed to the spinneret immersed in the coagulation bath. After passing through the spinneret, the viscose is sprayed into the coagulation bath. The concentration of sulfuric acid in the coagulation bath is 90 g / L, the concentration of zinc sulfate is 12 g / L, and the concentration of sodium sulfate is 260 g / L. After the fiber leaves the coagulation bath, it passes through the drawing plate and is further coagulated on the hot roller at 75°C. Then, it passes through the deacidification roller to remove excess coagulation bath. The spinning speed is controlled at 50 m / min during the spinning process.

[0040] Example 2

[0041] (1) Preparation of viscose: Cotton, wood, and bamboo pulps are impregnated, pressed, and crushed in an alkaline solution to obtain alkali cellulose; then aged, cooled, and subjected to xanthation reaction with carbon disulfide to transform the solid into a viscous liquid; then physically ground and dissolved, followed by degassing and multiple filtrations to remove bubbles and impurities, and finally matured to form viscose suitable for spinning. The maturation process is carried out in a maturation tank. After injecting 20 kg of viscose into the maturation tank, 5 g of potassium sulfate and 10 g of water-based polyurethane resin are added simultaneously, and the mixture is stirred for 27-30 hours using the stirrer of the maturation tank to ensure that the added substances are evenly dispersed in the viscose. Finally, the mixture is discharged for spinning. During the preparation process, the content of methyl cellulose in the viscose is controlled to be 1 kg.

[0042] (2) Spinning: The prepared viscose is pumped into the spindle filtration device by the metering pump of the spinning machine. After filtration, the viscose is conveyed to the spinneret immersed in the coagulation bath. After passing through the spinneret, the viscose is sprayed into the coagulation bath. The concentration of sulfuric acid in the coagulation bath is 93 g / L, the concentration of zinc sulfate is 10 g / L, and the concentration of sodium sulfate is 250 g / L. After the fiber leaves the coagulation bath, it passes through the drawing plate and is further coagulated and shaped on the hot roller at 80°C. Then, it passes through the deacidification roller to remove excess coagulation bath. The spinning speed is controlled at 45 m / min during the spinning process.

[0043] Example 3

[0044] (1) Preparation of viscose: Cotton, wood and bamboo pulp are soaked, pressed and crushed in alkaline solution to obtain alkali cellulose; then aged, cooled and xanthated with carbon disulfide to transform the solid into a viscous liquid; then physically ground and dissolved, then degassed and filtered through multiple channels to remove bubbles and impurities, and finally matured to form viscose that is ready for spinning. The maturation process is carried out in a maturation tank. After injecting 20 kg of viscose into the maturation tank, 39 g of potassium sulfate and 130 g of water-based polyurethane resin are added at the same time, and the mixture is stirred for 27 to 30 hours by the stirrer of the maturation tank to make the added substances evenly dispersed in the viscose. Finally, it is discharged for spinning. During the preparation process, the content of methyl cellulose in the viscose is controlled to be 1.3 kg.

[0045] (2) Spinning: The prepared viscose is pumped into the spindle filtration device by the metering pump of the spinning machine. After filtration, the viscose is conveyed to the spinneret immersed in the coagulation bath. After passing through the spinneret, the viscose is sprayed into the coagulation bath. The concentration of sulfuric acid in the coagulation bath is 96 g / L, the concentration of zinc sulfate is 11 g / L, and the concentration of sodium sulfate is 270 g / L. After the fiber leaves the coagulation bath, it passes through the drawing plate and is further coagulated and shaped on the hot roller at 70°C. Then, it passes through the deacidification roller to remove excess coagulation bath. The spinning speed is controlled at 55 m / min during the spinning process.

[0046] Example 4

[0047] (1) Preparation of viscose: Cotton, wood and bamboo pulps are soaked, pressed and crushed in alkaline solution to obtain alkali cellulose; then aged, cooled and xanthated with carbon disulfide to transform the solid into a viscous liquid; then physically ground and dissolved, then degassed and filtered through multiple channels to remove bubbles and impurities, and finally matured to form viscose suitable for spinning. The maturation process is carried out in a maturation tank. After injecting 20 kg of viscose into the maturation tank, 11 g of potassium sulfate and 22 g of water-based polyurethane resin are added at the same time, and the mixture is stirred for 27 to 30 hours by the stirrer of the maturation tank to make the added substances evenly dispersed in the viscose. Finally, it is discharged for spinning. During the preparation process, the content of methyl cellulose in the viscose is controlled to be 1.1 kg.

[0048] (2) Spinning: The prepared viscose is pumped into the spindle filtration device by the metering pump of the spinning machine. After filtration, the viscose is conveyed to the spinneret immersed in the coagulation bath. After passing through the spinneret, the viscose is sprayed into the coagulation bath. The concentration of sulfuric acid in the coagulation bath is 100 g / L, the concentration of zinc sulfate is 13 g / L, and the concentration of sodium sulfate is 300 g / L. After the fiber leaves the coagulation bath, it passes through the drawing plate and is further coagulated on the hot roller at 90°C. Then, it passes through the deacidification roller to remove excess coagulation bath. The spinning speed is controlled at 65 m / min during the spinning process.

[0049] Comparative Example 1

[0050] (1) Preparation of viscose: cotton, wood and bamboo pulp are soaked, pressed and crushed in alkaline solution to obtain alkali cellulose; then aged, cooled and xanthated with carbon disulfide to turn the solid into a viscous liquid; then physically ground and dissolved, then degassed and filtered through multiple channels to remove bubbles and impurities, and finally matured to form viscose with spinning conditions, which is then discharged for spinning; during the preparation process, the content of methyl cellulose in the viscose is controlled to be 1.2 kg.

[0051] (2) Spinning: The prepared viscose is pumped into the spindle filtration device by the metering pump of the spinning machine. After filtration, the viscose is conveyed to the spinneret immersed in the coagulation bath. After passing through the spinneret, the viscose is sprayed into the coagulation bath. The concentration of sulfuric acid in the coagulation bath is 90 g / L, the concentration of zinc sulfate is 12 g / L, and the concentration of sodium sulfate is 260 g / L. After the fiber leaves the coagulation bath, it passes through the drawing plate and is further coagulated on the hot roller at 75°C. Then, it passes through the deacidification roller to remove excess coagulation bath. The spinning speed is controlled at 50 m / min during the spinning process.

[0052] Comparative Example 2

[0053] (1) Preparation of viscose: Cotton, wood and bamboo pulp are soaked, pressed and crushed in alkaline solution to obtain alkali cellulose; then aged, cooled and xanthated with carbon disulfide to transform the solid into a viscous liquid; then physically ground and dissolved, then degassed and filtered through multiple channels to remove bubbles and impurities, and finally matured to form viscose suitable for spinning. The maturation process is carried out in a maturation tank. After injecting 20 kg of viscose into the maturation tank, 9.6 g of potassium sulfate is added at the same time, and the mixture is stirred for 27 to 30 hours by the stirrer of the maturation tank to make the added substances evenly dispersed in the viscose. Finally, it is discharged for spinning. During the preparation process, the content of methyl cellulose in the viscose is controlled to be 1.2 kg.

[0054] (2) Spinning: The prepared viscose is pumped into the spindle filtration device by the metering pump of the spinning machine. After filtration, the viscose is conveyed to the spinneret immersed in the coagulation bath. After passing through the spinneret, the viscose is sprayed into the coagulation bath. The concentration of sulfuric acid in the coagulation bath is 90 g / L, the concentration of zinc sulfate is 12 g / L, and the concentration of sodium sulfate is 260 g / L. After the fiber leaves the coagulation bath, it passes through the drawing plate and is further coagulated on the hot roller at 75°C. Then, it passes through the deacidification roller to remove excess coagulation bath. The spinning speed is controlled at 50 m / min during the spinning process.

[0055] Comparative Example 3

[0056] (1) Preparation of viscose: Cotton, wood and bamboo pulp are impregnated, pressed and crushed in alkaline solution to obtain alkali cellulose; then aged, cooled and xanthated with carbon disulfide to transform the solid into a viscous liquid; then physically ground and dissolved, then degassed and filtered through multiple channels to remove bubbles and impurities, and finally matured to form viscose suitable for spinning. The maturation process is carried out in a maturation tank. After injecting 20 kg of viscose into the maturation tank, 42 ​​g of water-based polyurethane resin is added at the same time, and the mixture is stirred for 27 to 30 hours by the stirrer of the maturation tank to make the added substances evenly dispersed in the viscose. Finally, it is discharged for spinning. During the preparation process, the content of methyl cellulose in the viscose is controlled to be 1.2 kg.

[0057] (2) Spinning: The prepared viscose is pumped into the spindle filtration device by the metering pump of the spinning machine. After filtration, the viscose is conveyed to the spinneret immersed in the coagulation bath. After passing through the spinneret, the viscose is sprayed into the coagulation bath. The concentration of sulfuric acid in the coagulation bath is 90 g / L, the concentration of zinc sulfate is 12 g / L, and the concentration of sodium sulfate is 260 g / L. After the fiber leaves the coagulation bath, it passes through the drawing plate and is further coagulated on the hot roller at 75°C. Then, it passes through the deacidification roller to remove excess coagulation bath. The spinning speed is controlled at 50 m / min during the spinning process.

[0058] Comparative Example 4

[0059] (1) Preparation of viscose: Cotton, wood, and bamboo pulps are impregnated, pressed, and crushed in an alkaline solution to obtain alkali cellulose; then aged, cooled, and subjected to xanthation reaction with carbon disulfide to transform the solid into a viscous liquid; then physically ground and dissolved, followed by degassing and multiple filtrations to remove bubbles and impurities, and finally matured to form viscose suitable for spinning. The maturation process is carried out in a maturation tank. After injecting 20 kg of viscose into the maturation tank, 9.6 g of potassium sulfate and 42 g of water-based polyurethane resin are added simultaneously, and the mixture is stirred for 27 to 30 hours using the stirrer of the maturation tank to ensure that the added substances are evenly dispersed in the viscose. Finally, the mixture is discharged for spinning. During the preparation process, the content of methyl cellulose in the viscose is controlled to be 1.2 kg.

[0060] (2) Spinning: The prepared viscose is pumped into the spindle filtration device by the metering pump of the spinning machine. After filtration, the viscose is conveyed to the spinneret immersed in the coagulation bath. After passing through the spinneret, the viscose is sprayed into the coagulation bath. The concentration of sulfuric acid in the coagulation bath is 130 g / L, the concentration of zinc sulfate is 12 g / L, and the concentration of sodium sulfate is 260 g / L. After the fiber leaves the coagulation bath, it passes through the drawing plate and is further coagulated and shaped on the hot roller at 75°C. Then, it passes through the deacidification roller to remove excess coagulation bath. The spinning speed is controlled at 50 m / min during the spinning process.

[0061] Comparative Example 5

[0062] (1) Preparation of viscose: Cotton, wood and bamboo pulp are soaked, pressed and crushed in alkaline solution to obtain alkali cellulose; then aged, cooled and xanthated with carbon disulfide to turn the solid into a viscous liquid; then physically ground and dissolved, then degassed and filtered through multiple channels to remove bubbles and impurities, and finally matured to form viscose that is ready for spinning. The maturation process is carried out in a maturation tank. After 20 kg of viscose is injected into the maturation tank, 9.6 g of potassium sulfate and 42 g of water-based polyurethane resin are added at the same time, and the mixture is stirred for 27 to 30 hours by the stirrer of the maturation tank to make the added substances evenly dispersed in the viscose. Finally, it is discharged for spinning. During the preparation process, the content of methyl cellulose in the viscose is controlled to be 1.7 kg.

[0063] (2) Spinning: The prepared viscose is pumped into the spindle filtration device by the metering pump of the spinning machine. After filtration, the viscose is conveyed to the spinneret immersed in the coagulation bath. After passing through the spinneret, the viscose is sprayed into the coagulation bath. The concentration of sulfuric acid in the coagulation bath is 90 g / L, the concentration of zinc sulfate is 12 g / L, and the concentration of sodium sulfate is 260 g / L. After the fiber leaves the coagulation bath, it passes through the drawing plate and is further coagulated on the hot roller at 75°C. Then, it passes through the deacidification roller to remove excess coagulation bath. The spinning speed is controlled at 50 m / min during the spinning process.

[0064] Comparative Example 6

[0065] (1) Preparation of viscose: Cotton, wood, and bamboo pulps are impregnated, pressed, and crushed in an alkaline solution to obtain alkali cellulose; then aged, cooled, and subjected to xanthation reaction with carbon disulfide to transform the solid into a viscous liquid; then physically ground and dissolved, followed by degassing and multiple filtrations to remove bubbles and impurities, and finally matured to form viscose suitable for spinning. The maturation process is carried out in a maturation tank. After injecting 20 kg of viscose into the maturation tank, 9.6 g of potassium sulfate and 42 g of water-based polyurethane resin are added simultaneously, and the mixture is stirred for 27 to 30 hours using the stirrer of the maturation tank to ensure that the added substances are evenly dispersed in the viscose. Finally, the mixture is discharged for spinning. During the preparation process, the content of methyl cellulose in the viscose is controlled to be 1.2 kg.

[0066] (2) Spinning: The prepared viscose is pumped into the spindle filtration device by the metering pump of the spinning machine. After filtration, the viscose is conveyed to the spinneret immersed in the coagulation bath. After passing through the spinneret, the viscose is sprayed into the coagulation bath. The concentration of sulfuric acid in the coagulation bath is 90 g / L, the concentration of zinc sulfate is 12 g / L, and the concentration of sodium sulfate is 260 g / L. After the fiber leaves the coagulation bath, it passes through the drawing plate and is further solidified on the coagulation roller at room temperature. Then it passes through the deacidification roller to remove excess coagulation bath. The spinning speed is controlled at 50 m / min during the spinning process.

[0067] Comparative Example 7

[0068] (1) Preparation of viscose: Cotton, wood, and bamboo pulps are impregnated, pressed, and crushed in an alkaline solution to obtain alkali cellulose; then aged, cooled, and subjected to xanthation reaction with carbon disulfide to transform the solid into a viscous liquid; then physically ground and dissolved, followed by degassing and multiple filtrations to remove bubbles and impurities, and finally matured to form viscose suitable for spinning. The maturation process is carried out in a maturation tank. After injecting 20 kg of viscose into the maturation tank, 9.6 g of potassium sulfate and 42 g of water-based polyurethane resin are added simultaneously, and the mixture is stirred for 27 to 30 hours using the stirrer of the maturation tank to ensure that the added substances are evenly dispersed in the viscose. Finally, the mixture is discharged for spinning. During the preparation process, the content of methyl cellulose in the viscose is controlled to be 1.2 kg.

[0069] (2) Spinning: The prepared viscose is pumped into the spindle filtration device by the metering pump of the spinning machine. After filtration, the viscose is conveyed to the spinneret immersed in the coagulation bath. After passing through the spinneret, the viscose is sprayed into the coagulation bath. The concentration of sulfuric acid in the coagulation bath is 90 g / L, the concentration of zinc sulfate is 12 g / L, and the concentration of sodium sulfate is 260 g / L. After the fiber leaves the coagulation bath, it passes through the drawing plate and is further coagulated on the hot roller at 75°C. Then, it passes through the deacidification roller to remove excess coagulation bath. The spinning speed is controlled at 150 m / min during the spinning process.

[0070] Experimental Example 1

[0071] Based on Example 1, the preparation conditions were changed to obtain Comparative Examples 1 to 7.

[0072] In this experiment, samples prepared in Examples 1 to 4 and Comparative Examples 1 to 7 were treated with hot water at the same temperature for the same amount of time, and then the shrinkage rate of the samples was tested. The test results are shown in Table 1.

[0073] Table 1

[0074]

[0075] As shown in Table 1, Examples 1 to 4 prepared viscose filaments according to the method of the present invention. During the curing process of viscose preparation, appropriate amounts of metal sulfate salts and curing agents were added. The metal sulfate salts effectively increased the generation rate of crystal nuclei inside the fiber, reducing the proportion of amorphous regions. The curing agent formed a tiny sponge-like network inside the fiber, solidifying to form the internal framework structure of the fiber, which was used to fix the internal structure of the fiber. The content of methyl cellulose in the viscose was controlled and reduced, thereby increasing the concentration difference between the viscose and the coagulation bath, increasing the double diffusion rate of the viscose and the coagulation bath, and improving the degree of reaction. The sulfuric acid concentration in the coagulation bath during spinning was reduced to reduce the intensity of the reaction of the nascent filaments. In the subsequent coagulation and forming process, the temperature was increased by using hot rollers to compensate for the forming conditions, making the internal structure of the fiber more uniform and dense. At the same time, the spinning speed was controlled and reduced to make the fiber forming more complete, which could further improve the crystallinity of the fiber.

[0076] Through the synergistic effect of the above improvement measures, the overall rate of crystal nucleation in viscose during spinning is increased, the crystal nuclei are arranged more tightly, the proportion of crystalline regions is larger than that of amorphous regions, the overall fiber density is improved, stress is reduced, the shrinkage rate after exposure to hot water is significantly reduced, and the fiber spinnability is better.

[0077] In Comparative Example 1, because no metal sulfate salts and curing agents were added during the curing process, the generated rate of internal crystal nuclei in the prepared fiber was low, the internal structure of the fiber was not strong, the proportion of amorphous region was large, the fiber's resistance to deformation was poor, and the shrinkage rate was large.

[0078] In Comparative Example 2, because no curing agent was added during the curing process, the internal structure of the fiber was not very strong, the fiber's resistance to deformation was poor, and the shrinkage rate was relatively large.

[0079] In Comparative Example 3, because no metal sulfate salt was added during the curing process, the rate of crystal nucleation inside the prepared fiber was low, resulting in a larger proportion of amorphous regions, poor fiber resistance to deformation, and a larger shrinkage rate.

[0080] In Comparative Example 4, when the sulfuric acid concentration in the coagulation bath is high, the skin forming speed during the fiber forming process is too fast, resulting in excessively high density. This can easily cause difficulties in subsequent diffusion in the coagulation bath, leading to a greater shrinkage rate of the final viscose filament.

[0081] In Comparative Example 5, when the content of methyl cellulose in the viscose is relatively high, the reaction during the viscose preparation process is incomplete, resulting in a larger shrinkage rate of the final viscose filament.

[0082] In Comparative Example 6, the sulfuric acid concentration in the coagulation bath was low, and the use of a room-temperature coagulation roller for spinning during the spinning process reduced the fiber forming conditions, resulting in poor fiber forming effect and ultimately leading to a larger shrinkage rate of the viscose filament.

[0083] In Comparative Example 7, when the spinning speed is high, the fiber formation is insufficient, which reduces the crystallinity of the fiber and increases the shrinkage rate of the viscose filament.

[0084] Experimental Example 2

[0085] Based on Example 1, this experiment changed the percentage of metal sulfate salt in the mass of cellulose ether while keeping other preparation conditions unchanged, resulting in Comparative Examples 8 to 14. The samples were then treated with hot water at the same temperature for the same duration, and the shrinkage rate of the samples was tested. The test results are shown in Table 2.

[0086] Table 2

[0087]

[0088]

[0089] As can be seen from Table 2, when the mass percentage of metal sulfate to viscose fiber is within the range defined by this invention, such as Comparative Examples 9 to 13 and Example 1, the shrinkage rate of the viscose filaments prepared is significantly reduced. In particular, when the mass percentage of metal sulfate to viscose fiber is in the range of 0.5% to 1%, the shrinkage rate of the viscose filaments prepared is as low as 0.9% or less, and the fiber spinnability is good.

[0090] However, when the amount of metal sulfate added is small, such as in Comparative Example 8, the metal sulfate has little effect, the generation rate of crystal nuclei inside the fiber is relatively small, the proportion of amorphous region is large, the fiber density is small, resulting in poor fiber resistance to deformation and increased shrinkage.

[0091] When the amount of added metal sulfate salt is high, such as in Comparative Example 14, further increasing the amount does not have a significant effect on the shrinkage rate. On the contrary, further increasing the amount will lead to difficulties in subsequent filtration, and at the same time affect the spinnability of the yarn, making it easy to cause yarn breakage.

[0092] Experimental Example 2

[0093] Based on Example 1, this experiment changed the percentage of curing agent to fiber methyl methacrylate while keeping other preparation conditions unchanged, resulting in Comparative Examples 15 to 22. The samples were then treated with hot water at the same temperature for the same duration, and the shrinkage rate was tested. The test results are shown in Table 3.

[0094] Table 3

[0095]

[0096] As can be seen from Table 3, when the mass of the curing agent accounts for the mass of the viscose fiber within the limits of this invention, such as Comparative Examples 16 to 21 and Example 1, the shrinkage rate of the viscose filaments prepared is significantly reduced. In particular, when the mass of the curing agent accounts for the mass of the viscose fiber in the range of 2% to 3.5%, the shrinkage rate of the viscose filaments prepared is as low as less than 0.9%, and the fiber spinnability is good.

[0097] However, when the amount of curing agent added is small, such as in Comparative Example 15, the curing agent has little effect, forming less sponge-like network inside the fiber, and has a weak curing effect on the framework structure inside the fiber, resulting in poor fiber resistance to deformation and increased shrinkage.

[0098] However, when the amount of curing agent added is high, such as in Comparative Example 22, although the shrinkage rate can be further reduced by continuing to increase the amount of curing agent, the contribution is not significant. After adding too much, the spinnability of the fiber deteriorates sharply and the yield is extremely low. Moreover, the fiber is too rigid and its bending resistance is poor, which affects the fiber's inability to be woven in subsequent processes.

[0099] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A process for the production of low-shrinkage viscose filaments, characterized in that, It comprises the following steps: (1) preparing viscose: pulp is dipped in lye, pressed, crushed to obtain alkali cellulose, then aged, cooled, yellowed, ground, dissolved, defoamed, filtered, matured, and metal sulfate and solidifying agent are added during the maturing process to prepare viscose; The mass of methyl cellulose in the viscose is 5-6.5% of the mass of the viscose, the mass of the metal sulfate is 0.5-3% of the mass of the methyl cellulose, and the mass of the solidifying agent is 1-3.5% of the mass of the methyl cellulose; The solidifying agent is water-based polyurethane resin; (2) spinning: the viscose is processed by a metering pump, a filter, a spinneret, a coagulation bath, a hot roller, and an acid-removing roller to spin; The concentration of sulfuric acid in the coagulation bath is 90-100 g / L; The temperature of the hot roller is controlled at 70-90℃, and the spinning speed during the spinning process is 45-65 m / min.

2. A process for the production of low shrinkage viscose filaments according to claim 1, characterized in that, The metal sulfate is selected from one or more of potassium sulfate, zinc sulfate, and aluminum sulfate.

3. A process for the production of low shrinkage viscose filaments according to claim 1, characterized in that, The metal sulfate is potassium sulfate.

4. A process for the production of low shrinkage viscose filaments according to any one of claims 1 to 3, characterized in that The mass of the methyl cellulose in the viscose is 6% of the mass of the viscose.

5. A process for the production of low shrinkage viscose filaments according to any one of claims 1 to 3, characterized in that The mass of the metal sulfate is 0.5-1% of the mass of the methyl cellulose.

6. A process for the production of low shrinkage viscose filaments according to any one of claims 1 to 3, characterized in that, The mass of the solidifying agent is 2-3.5% of the mass of the methyl cellulose.

7. A process for the production of low shrinkage viscose filaments according to any one of claims 1 to 3, characterized in that, The coagulation bath is a mixture of sulfuric acid, zinc sulfate, and sodium sulfate.

8. A process for the production of low shrinkage viscose filaments according to any one of claims 1 to 3, characterized in that, The temperature of the hot roller is controlled at 70-75℃.

9. A process for the production of low shrinkage viscose filaments according to any one of claims 1 to 3, characterized in that, The spinning speed during the spinning process is 45-50 m / min.

10. A low shrinkage viscose filament, characterized in that, The low-shrinkage viscose filament is prepared by the method of any one of claims 1-9, and the shrinkage of the viscose filament is less than 1%.

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