Production process for improving performance of viscose staple fibers

Abstract

The invention relates to a production process for improving the performance of viscose staple fibers, which comprises a spinning machine, an acid bath tank, a nozzle assembly, a metering pump, a desulfurization spray-wash assembly and a first whitening spray-wash assembly.The production process comprises the following steps: pretreating a cellulose raw material to obtain viscose, and conveying the viscose to the nozzle assembly in the acid bath tank through the metering pump for spinning; tows sprayed by the spray head assembly are soaked in acid bath circulating liquid of the acid bath tank by a preset depth, then conveyed backwards through a godet of the spinning machine, and subjected to desulfurization and whitening treatment through the desulfurization spray washing assembly and the first whitening spray washing assembly after being drafted and cut off; a desulfurization spray-washing solution used in the desulfurization spray-washing assembly is a mixed solution containing sodium sulfide and alkali; a whitening solution used in the first whitening spray-washing assembly is a sodium hypochlorite solution, and a hydrogen peroxide solution is added in the pretreatment process of the cellulose raw material for dipping; and the circulating speed of the acid bath circulating liquid in the acid bath tank is 5%-10% higher than the spinning speed of the nozzle assembly.

Description

Technical Field

[0001] This invention relates to the field of viscose staple fiber production, and more specifically to a production process for improving the properties of viscose staple fibers. Background Technology

[0002] Viscose staple fiber, a high-polymer regenerated fiber of natural cellulose, is mainly produced by using natural cellulose as the basic raw material. The cellulose xanthate solution is then prepared and reacted with an acid bath at the spinning machine to form regenerated cellulose fibers. Natural fibers such as cotton and wool have low whiteness, significant spinnability deviations, and trace amounts of oil on their surface. Viscose staple fiber, however, undergoes various chemical reactions during production, especially the formation of polysulfides, which reduces its original whiteness, resulting in a yellowish and uneven fiber appearance. Therefore, it is necessary to improve the spinnability of viscose staple fiber at the front end and improve its whiteness and residual sulfur properties through back-end processing. Generally, to remove polysulfides from viscose staple fiber after the reaction, the alkali consumption is 10-25 kg per ton of fiber. For viscose staple fiber with unstable whiteness indicators, whitening treatment is required, consuming 2-9 kg of sodium hypochlorite and 2-15 kg of hydrogen peroxide per ton of fiber. Summary of the Invention

[0003] In order to solve one or more technical problems existing in the prior art, the present invention provides a production process for improving the properties of viscose staple fiber.

[0004] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: The present invention provides a production process for improving the performance of viscose staple fiber, including a spinning machine, an acid bath, a nozzle assembly, a metering pump, a desulfurization spray washing assembly and a first whitening spray washing assembly. Cellulose raw material is pretreated to obtain viscose. The viscose is transported to the nozzle assembly in the acid bath for spinning by the metering pump. The fiber bundles spun out by the nozzle assembly are immersed in the acid bath circulating liquid in the acid bath to a preset depth, and then conveyed backward by the guide roller of the spinning machine. After being drawn and cut, they are desulfurized and whitened by the desulfurization spray washing assembly and the first whitening spray washing assembly, respectively. The desulfurization spraying solution used in the desulfurization spraying assembly is a mixed solution containing sodium sulfide and alkali, wherein the concentration of sodium sulfide in the mixed solution is 1g / L~4g / L and the concentration of alkali in the mixed solution is 1g / L~4g / L; the whitening solution used in the first whitening spraying assembly is a sodium hypochlorite solution, and the cellulose raw material is impregnated with hydrogen peroxide solution during the pretreatment process. The circulation speed of the acid bath fluid in the acid bath tank is 5% to 10% higher than the spinneret speed of the nozzle assembly, and the circulation volume of the acid bath fluid in the acid bath tank is 10m³. 3 ~25m 3 Acid bath circulating fluid / 1m 3 Adhesive.

[0005] The beneficial effects of this invention are as follows: This invention provides a production process for improving the properties of viscose staple fibers. By adding hydrogen peroxide solution to the impregnation solution of the fiber raw material, the viscosity of the viscose can be improved by changing the concentration of the hydrogen peroxide solution and the impregnation time, thus meeting different viscose viscosity requirements. Adding hydrogen peroxide solution to the impregnation solution before pressing can improve whiteness and also play a role in cellulose degradation, thereby improving the uniformity and stability of the whiteness of the viscose staple fibers. By controlling the circulation speed and volume of the acid bath circulating solution in the acid bath tank, the strength of the viscose staple fibers can be improved, and the spinnability can be enhanced.

[0006] This invention improves the residual sulfur and whiteness properties of viscose staple fiber by adjusting the process solution, adjusting the concentration of the process solution, and adjusting the location where the process solution is added.

[0007] Based on the above technical solution, the present invention can be further improved as follows.

[0008] Furthermore, each metering pump corresponds to one spindle, the metering pump discharges glue at a rate of 60 mL / rpm to 150 mL / rpm, and the nozzle assembly has 30,000 to 140,000 nozzles per spindle.

[0009] The beneficial effects of adopting the above-mentioned further scheme are: the metering pump quantitatively delivers adhesive to the nozzle assembly, making the fineness of the formed fiber stable and uniform. Each metering pump corresponds to one spindle, increasing the adhesive output on the basis of the original metering pump output, thus meeting production needs.

[0010] Furthermore, the inlet channel at the front end of the nozzle orifice of the nozzle assembly is a cone-shaped structure with a hyperboloid surface.

[0011] The beneficial effects of adopting the above-mentioned further solution are: the inlet channel at the front end of the nozzle adopts a hyperboloid transition, which can reduce the inlet effect of adhesive at the nozzle inlet channel, improve spinnability, and increase strength.

[0012] Furthermore, the ratio of the nozzle orifice diameter to the nozzle orifice length of the nozzle assembly is 1:(1~5).

[0013] Furthermore, the preset depth is 750mm~850mm.

[0014] The beneficial effect of adopting the above-mentioned further scheme is that by using an immersion depth of 750mm~850mm, the total tension of the filaments can be increased without causing excessive resistance of the filament bundle in the acid bath circulating liquid.

[0015] Furthermore, the concentrations of each component in the acid bath circulating solution are: sulfuric acid 70 g / L~150 g / L, sodium sulfate 100 g / L~400 g / L, and zinc sulfate 6 g / L~50 g / L.

[0016] Furthermore, it also includes a second whitening spray washing assembly, wherein the filament bundle is whitened by the first whitening spray washing assembly and then whitened a second time by the second whitening spray washing assembly; the whitening solution used in the second whitening spray washing assembly is a hydrogen peroxide solution.

[0017] The beneficial effect of adopting the above-mentioned further solution is that for some viscose staple fibers with high cleanliness requirements, it is necessary to increase the circulation of hydrogen peroxide solution to improve the whiteness of viscose staple fibers.

[0018] Furthermore, the concentration of hydrogen peroxide solution used in the second whitening spray washing component is 0.1~2g / L.

[0019] Furthermore, the concentration of hydrogen peroxide solution added during the pretreatment process is 0.1~2 g / L.

[0020] Furthermore, during the process of the adhesive being spun through the nozzle assembly, the degree of expansion of the adhesive is 1% to 3%.

[0021] This invention primarily improves the spinnability of viscose staple fibers by controlling the acid bath and viscose parameters involved in the reaction at the spinning machine. Improvements to performance indicators such as whiteness and residual sulfur mainly involve improvements to the spray washing treatment and washing solution after the viscose staple fibers form a felt. Improvements to performance indicators such as dyeability, dry breaking strength, and defects are improvements to spinnability; improvements to performance indicators such as whiteness and residual sulfur are improvements to the post-processing. These two improvements to the spinnability of viscose staple fibers at the beginning and in the post-processing are crucial for improving the overall performance of viscose staple fibers. Attached Figure Description

[0022] Figure 1 This is a schematic flow diagram of a production process for improving the properties of viscose staple fiber according to the present invention; Figure 2 This is a schematic diagram of the structure of the nozzle assembly of the present invention in conjunction with the acid bath and the spinning machine; Figure 3 This is a schematic diagram illustrating the expansion principle of adhesive during the filament spinning process in the nozzle; Figure 4 This is a schematic diagram of the existing nozzle structure; Figure 5 This is a schematic diagram of the nozzle structure of the present invention; Figure 6 This is a schematic diagram of the desulfurization and whitening process structure of the present invention.

[0023] The attached diagram lists the components represented by each number as follows: 1. Spinning machine; 11. Guide roller; 2. Acid bath; 3. Nozzle assembly; 31. Nozzle; 32. Filter; 33. Inlet channel; 34. Spray hole; 35. Expansion zone; 4. Metering pump; 5. Fiber bundle; 6. Desulfurization liquid circulation tank; 61. Desulfurization liquid circulation pump; 62. Desulfurization liquid circulation trough; 63. Desulfurization liquid nozzle; 7. Bleach solution circulation tank; 71. Bleach solution circulation pump; 72. Bleach solution circulation trough; 73. Bleach solution nozzle; 8. Hydrogen peroxide circulation tank; 81. Hydrogen peroxide circulation pump; 82. Hydrogen peroxide circulation tank; 83. Hydrogen peroxide nozzle. Detailed Implementation

[0024] The principles and features of the present invention are described below. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0025] Example 1 like Figures 1-3 , Figure 5 and Figure 6 As shown, this embodiment of a production process for improving the properties of viscose staple fiber includes a spinning machine 1, an acid bath 2, a nozzle assembly 3, a metering pump 4, a desulfurization spray washing assembly, and a first whitening spray washing assembly. Cellulose raw material is pretreated to obtain viscose. The viscose is transported by the metering pump 4 to the nozzle assembly 3 in the acid bath 2 for spinning. The fiber bundle 5 ejected by the nozzle assembly 3 is immersed in the acid bath circulating liquid of the acid bath 2 to a predetermined depth, and then conveyed backward by the guide roller 11 of the spinning machine 1. After being drawn and cut, it undergoes desulfurization and whitening treatments by the desulfurization spray washing assembly and the first whitening spray washing assembly, respectively. The desulfurization spray washing assembly... The desulfurization spraying solution used in the first whitening spraying assembly is a mixed solution containing sodium sulfide and alkali, wherein the concentration of sodium sulfide and alkali in the mixed solution is 1-4 g / L; the whitening solution used in the first whitening spraying assembly is a sodium hypochlorite solution, and hydrogen peroxide solution is added to the cellulose raw material for impregnation during the pretreatment process; the concentration of hydrogen peroxide solution added during the pretreatment process is 0.1-2 g / L; the circulation speed of the acid bath circulating liquid in the acid bath tank 2 is 5%-10% higher than the spinning speed of the nozzle assembly 3, and the circulation volume of the acid bath circulating liquid in the acid bath tank 2 is 10-25 m³ / h. 3 Acid bath circulating fluid / 1m 3 Adhesive.

[0026] This embodiment uses a mixed solution containing sodium sulfide and dilute alkali to spray-wash the fiber felt in order to improve residual sulfur performance and optimize the desulfurization cycle process. This saves on concentrated alkali consumption, reduces costs, and lowers the residual sulfur index. Adding hydrogen peroxide solution during pretreatment achieves a whitening effect and improves the uniformity and stability of whiteness. Existing desulfurization processes suffer from strong alkalinity of sodium hydroxide, resulting in a vigorous reaction that produces an odor that cannot be effectively removed in subsequent processes. Therefore, optimizing the desulfurization process requires selecting a milder desulfurizing agent to replace the sodium hydroxide solution. The desulfurization reaction process involves sodium hydroxide reacting with acid to produce sodium sulfide and sodium hydrosulfide. Sodium sulfide then reacts with sulfur compounds in the fibers to achieve desulfurization. Since sodium sulfide can be produced from waste gas recovery byproducts, it is a good alternative desulfurizing agent. Considering the actual site conditions, the use of sodium sulfide desulfurization is deemed feasible, as it effectively improves fiber odor and is less expensive than sodium hydroxide. A common whitening system process involves preparing a bleaching solution containing 5-15% available chlorine and 0.2-2% free alkali into a 0.4-2 g / L whitening solution, which is then circulated using a pump to convert metallic impurities such as calcium and iron salts adhering to the fibers into soluble substances. When using sodium hypochlorite for whitening, the pH value of the circulating solution is strictly controlled, generally between 8 and 10. When pH < 8, viscose staple fibers are easily damaged, and sodium hypochlorite decomposes significantly; when pH > 10, the fibers are not easily damaged, but colored substances are not oxidized, thus failing to achieve the whitening effect. For some viscose staple fibers requiring high cleanliness, hydrogen peroxide circulation is added (Example 2). The fiber felt is sprayed with a hydrogen peroxide solution containing 0.1-2 g / L, and the solution is circulated using a pump to improve the whiteness of the viscose staple fibers. The hydrogen peroxide circulation system added to the pressing process involves adding a metered solution of 0.1~2g / l of hydrogen peroxide to a soaking tank and into the press's pipeline via a metering pump. This serves to both oxidize and degrade cellulose, preventing excessive damage to cellulose macromolecules, and improve the whiteness of the cellulose.

[0027] In a preferred embodiment, each metering pump 4 corresponds to one spindle, the metering pump 4 has a glue dispensing rate of 60~150mL / rpm, and the number of nozzles 34 in the nozzle assembly 3 is 30,000~140,000 per spindle. In another preferred embodiment, the ratio of the nozzle diameter to the length of the nozzle 34 in the nozzle assembly 3 is 1~5.

[0028] Metering pumps quantitatively deliver viscose to the nozzle assembly, ensuring stable and uniform fiber fineness. Each metering pump corresponds to one spindle. The viscose output has been increased from the original metering pump output to meet production demands. The metering pumps quantitatively deliver viscose to the nozzle assembly, ensuring stable and uniform fiber fineness. Each metering pump corresponds to one spindle. Increasing the viscose output from 60-80 ml / rpm to 60-150 ml / rpm meets production needs. After a period of operation, the viscose output may change due to wear or improper use, requiring periodic inspection of the metering pumps. The nozzle divides the accurately metered viscose into multiple uniform fine streams. These viscose streams react with the acid bath through the spinneret orifices to form filament bundles of a specific fineness. Currently, the number of orifices per nozzle has increased from 30,000-76,000 per spindle to 30,000-140,000 per spindle, matched to different product varieties. To reduce the inlet effect of viscose at the nozzle outlet, the nozzle orifice shape has been changed from trapezoidal to hyperbolic. The viscose experiences flow resistance in the nozzle's inlet channel. Increasing the inlet channel size reduces the effect of the viscose stream at the nozzle orifice outlet, improving spinnability and increasing strength. However, if the overall nozzle orifice is too long, the flow resistance to the viscose stream increases rapidly, affecting spinnability. Therefore, while maintaining L / d = 1~5, the nozzle orifice diameter d is generally limited to 0.04~0.08 mm, thus restricting the length of the nozzle orifice. Before use, the nozzle must undergo rigorous inspection. Any nozzles showing corrosion, deformation, or blockage should be replaced immediately, as these issues affect the inlet and swelling effects, thereby impacting spinnability.

[0029] A preferred embodiment of this solution is as follows: Figure 5 As shown, the inlet channel 33 at the front end of the nozzle 34 of the nozzle assembly is a cone-shaped structure with a hyperboloid surface. Figure 4 The existing inlet channel has a conical structure. The inlet channel at the nozzle tip adopts a hyperboloid transition, which can reduce the inlet effect of adhesive at the nozzle inlet channel, improve spinnability, and increase strength.

[0030] In a preferred embodiment, the preset depth is 750mm to 850mm. Using an immersion depth of 750mm to 850mm increases the total tension of the filaments without causing excessive resistance in the acid bath circulation solution. Increasing the immersion depth of the viscose stream in the acid bath results in more uniform viscose formation, better spinnability, and higher fiber strength. However, increased immersion depth increases the resistance experienced by the filaments in the acid bath, accounting for 20% to 40% of the total resistance, and correspondingly increases the tension of the filaments. When the immersion depth increases from 220mm to 920mm, the total tension of the filaments is 3.5 to 4 times the original. Through actual production trials, it has been determined that an immersion depth of 750 to 850mm in the acid bath is preferable.

[0031] Specifically, the concentrations of each component in the acid bath circulating solution are: sulfuric acid 70g / L~150g / L, sodium sulfate 100g / L~400g / L, and zinc sulfate 6g / L~50g / L. The sulfuric acid concentration in the acid bath varies depending on the type of viscose staple fiber during the forming reaction. Lowering the sulfuric acid concentration reduces the sheath layer of the fiber bundle and the maximum spinneret stretch, resulting in poor spinnability. To ensure spinnability, the fluctuation of the acid bath concentration needs to be controlled within a certain range, while the acid bath circulation rate should be maintained above a certain level. When the acid bath circulation rate is 5~10% higher than the extrusion rate of the viscose stream, the strength of the viscose staple fiber can be improved, thus enhancing spinnability. The appropriate ranges for sulfuric acid concentration, sodium sulfate concentration, zinc sulfate concentration, and circulation rate are determined based on different viscose staple fiber varieties to ensure spinnability. The core-sheath ratio of nascent viscose fiber needs attention, as the acid bath contains H... + No Zn 2+ It's a core, it contains Zn 2+ No H + It is skin; H in acid bath + Low concentration, Zn 2+ High concentrations result in more skin formation and greater strength. Increasing the skin structure can also improve the spinnability and medium strength properties of viscose staple fibers by reducing the degree of esterification, increasing the amount of carbon disulfide, reducing the degree of ripening, lowering the acid bath temperature, increasing the degree of polymerization at the aging outlet, increasing the concentration of sodium sulfate, and increasing the concentration of zinc sulfate.

[0032] The nozzle assembly in this embodiment can be produced using commonly used nozzle manufacturing equipment for viscose staple fibers. Specifically, such as... Figure 2 As shown, the nozzle assembly 3 in this embodiment includes a nozzle 31 and a filter 32, with the filter 32 installed at the front end of the nozzle 31.

[0033] The desulfurization spray washing assembly and the first whitening spray washing assembly described in this embodiment can be commonly used equipment for viscose short fiber desulfurization and whitening. Specifically, such as... Figure 6As shown, the desulfurization spraying assembly includes a desulfurization liquid circulation tank 6, a desulfurization liquid circulation pump 61, a desulfurization liquid circulation trough 62, and a desulfurization liquid nozzle 63. The bottom of the desulfurization liquid circulation trough 62 is connected to the top of the desulfurization liquid circulation tank 6 via a pipeline. The bottom sidewall of the desulfurization liquid circulation tank 6 is connected to the desulfurization liquid nozzle 63 via a first circulation pipeline. The desulfurization liquid nozzle 63 is arranged towards the filament bundle 5 between the guide rollers and is used to spray desulfurization liquid onto the filament bundle 5. Desulfurization liquid is installed on the first circulation pipeline. The first whitening spray assembly includes a bleaching solution circulation tank 7, a bleaching solution circulation pump 71, a bleaching solution circulation trough 72, and a bleaching solution nozzle 73. The bottom of the bleaching solution circulation trough 72 is connected to the top of the bleaching solution circulation tank 7 via a pipeline. The bottom side wall of the bleaching solution circulation tank 7 is connected to the bleaching solution nozzle 73 via a second circulation pipeline. The bleaching solution nozzle 73 is arranged towards the yarn bundle 5 between the guide rollers and is used to spray bleaching solution onto the yarn bundle 5. The bleaching solution circulation pump 71 is installed on the second circulation pipeline.

[0034] Different types of viscose staple fiber have different upper limits for viscosity. However, when the viscosity of viscose staple fiber is below 20 seconds, there is almost no possibility of forming filaments. Conversely, when the viscosity exceeds the upper limit for a particular type of viscose staple fiber, the orifice and swelling effects intensify, which in turn reduces the maximum spinneret stretch. In the production of ordinary viscose staple fiber, the maximum spinneret stretch reaches its maximum at a viscosity of 50 seconds, resulting in stable forming and good spinnability. Therefore, to ensure the spinnability of viscose staple fiber, although the viscose viscosity is controlled between 30 and 140 seconds, with a fluctuation range of ±3 to 5 seconds, the viscosity range needs to be adjusted according to different varieties. In this embodiment, hydrogen peroxide solution is added during pretreatment, specifically during the impregnation process. The viscosity of the viscose staple fiber can be adjusted by the amount of hydrogen peroxide added and the impregnation time. If it is necessary to increase the viscosity of the viscose staple fiber, the hydrogen peroxide concentration can be reduced and / or the impregnation time can be shortened; if it is necessary to decrease the viscosity of the viscose staple fiber, the hydrogen peroxide concentration can be increased and / or the impregnation time can be shortened.

[0035] In this embodiment, during the spinning process of the viscose through the nozzle assembly, the degree of viscose swelling is 1%~3%. Two effects (inlet effect and swelling effect) affect the spinnability of the fiber during the formation of nascent fibers, primarily impacting the strength and dyeability of viscose staple fibers. Reducing the swelling effect and inlet effect increases the maximum stretch of the nozzle, improves the strength of the finished fiber, and enhances the uniformity of fiber dyeing; therefore, reducing the inlet effect and swelling effect is a direction for improvement. The swelling effect occurs when a fine stream of viscose is extruded from the small orifice of the nozzle, and a swelling zone 35 with an increased diameter appears near the orifice (e.g., ...). Figure 3As shown in the diagram, an expansion effect occurs; the inlet effect is the phenomenon where the viscous fluid, upon entering the nozzle inlet, is forced from a larger diameter space into a smaller diameter spinneret channel. At the inlet, the viscous fluid generates a velocity gradient and consumes some energy, storing it as elastic energy. The inlet effect plays a crucial role in the movement of the viscous fluid within the nozzle channel, and stabilizing the velocity is very important. When the viscous fluid moves within the channel, the Reynolds number is very small (Re << 1), and the length L required for the viscous fluid to reach a stable velocity is... E =0.03*Re*d in L E / d<<1, while the length-to-diameter ratio (L / d) of a typical nozzle orifice is approximately 1~5. Therefore, the stable velocity of the viscose stream is already fully stabilized at the very beginning of the spinneret channel. The index for measuring the swelling effect of the viscose stream is the degree of swelling ψ=d. f / d (e.g.) Figures 3-5 As shown in the figure, the swelling degree of viscose fiber is generally in the range of 1% to 3%. Swelling degree has a significant impact on the spinnability of viscose fiber. Maintaining the swelling degree is crucial during viscose fiber production. Therefore, if the swelling degree ψ is too high or too low at the beginning of the spinneret, it can be adjusted and improved in the following ways: increasing the degree of polymerization and decreasing the viscose temperature can increase the swelling degree ψ; decreasing the nozzle diameter and extending the residence time of the viscose in the channel can decrease the swelling degree ψ; reducing the amount of viscose extruded per spindle can decrease the swelling degree ψ; changing the shape of the spinneret (from trapezoidal to hyperbolic) can also decrease the swelling degree ψ.

[0036] In this embodiment of a production process for improving the properties of viscose staple fibers, any unmentioned processes can be employed using common viscose staple fiber processes, such as... Figure 1 As shown, the pretreatment process specifically includes feeding meal, impregnation, pressing, crushing, aging, xanthation, dissolution, maturation, filtration, and degassing. Cellulose raw materials are converted into viscose through the pretreatment process. The acid bath solution is degassed, filtered, and prepared as the acid bath circulating liquid. After the viscose and acid bath circulating liquid are mixed and reacted in the spinning machine, the viscose is drawn and cut before entering the post-treatment process. The post-treatment process includes washing, desulfurization, washing again, whitening, drying, and packaging. This embodiment mainly involves adding hydrogen peroxide to the impregnation solution, adjusting the acid bath circulating liquid, re-adjusting the desulfurization and whitening solutions, and controlling the structural parameters of the nozzle assembly. This allows for process control of both the pretreatment and post-treatment processes, thereby improving the strength and spinnability of viscose staple fibers.

[0037] This embodiment describes a production process for improving the properties of viscose staple fibers. By adding hydrogen peroxide solution to the impregnation solution of the fiber raw material, the viscosity of the viscose can be improved by varying the concentration of the hydrogen peroxide solution and the impregnation time, thus meeting different viscose viscosity requirements. Adding hydrogen peroxide solution to the impregnation solution before pressing not only improves whiteness but also plays a role in cellulose degradation, thereby improving the uniformity and stability of the whiteness of the viscose staple fibers. By controlling the circulation speed and volume of the acid bath circulating solution in the acid bath tank, the strength of the viscose staple fibers can be increased, and their spinnability can be improved.

[0038] This embodiment improves the residual sulfur and whiteness properties of viscose staple fiber by adjusting the process solution, adjusting the concentration of the process solution, and adjusting the location where the process solution is added.

[0039] Example 2 Based on Example 1, this example also provides a further whitening solution. For example... Figure 6 As shown, the production process for improving the performance of viscose staple fibers in this embodiment further includes a second whitening spray washing assembly. The fiber bundle undergoes whitening treatment through the first whitening spray washing assembly and then undergoes secondary whitening treatment through the second whitening spray washing assembly. The whitening solution used in the second whitening spray washing assembly is a hydrogen peroxide solution. For some viscose staple fibers with high cleanliness requirements, it is necessary to increase the circulation of hydrogen peroxide solution to improve the whiteness of the viscose staple fibers.

[0040] Specifically, the concentration of hydrogen peroxide solution added during the pretreatment process is 0.1~2 g / L, and the concentration of hydrogen peroxide solution used in the second whitening spray washing component is 0.1~2 g / L.

[0041] The second whitening spray washing component in this embodiment can be a commonly used equipment for desulfurization and whitening of viscose short fibers. Specifically, such as... Figure 6 As shown, the second whitening spray washing assembly of this embodiment includes a hydrogen peroxide circulation tank 8, a hydrogen peroxide circulation pump 81, a hydrogen peroxide circulation trough 82, and a hydrogen peroxide nozzle 83. The bottom of the hydrogen peroxide circulation trough 82 is connected to and communicates with the top of the hydrogen peroxide circulation tank 8 through a pipeline. The bottom side wall of the hydrogen peroxide circulation tank 8 is connected to and communicates with the hydrogen peroxide nozzle 83 through a third circulation pipeline. The hydrogen peroxide nozzle 83 is arranged towards the filament bundle 5 between the guide rollers and is used to spray hydrogen peroxide onto the filament bundle 5. The hydrogen peroxide circulation pump 81 is installed on the third circulation pipeline.

[0042] This embodiment, by setting a second whitening spray washing component, can improve the whiteness of viscose short fibers with high cleanliness requirements.

[0043] In the description of this invention, it should be understood that the terms "inner" and "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0044] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0045] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0046] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0047] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0048] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A production process for improving the properties of viscose staple fiber, characterized in that, The system includes a spinning machine, an acid bath, a nozzle assembly, a metering pump, a desulfurization spray washing assembly, and a first whitening spray washing assembly. Cellulose raw materials are pretreated to obtain viscose. The viscose is transported to the nozzle assembly in the acid bath by the metering pump for spinning. The filaments spun out by the nozzle assembly are immersed in the acid bath circulating liquid in the acid bath to a preset depth, and then conveyed backward by the guide roller of the spinning machine. After being drawn and cut, they are desulfurized and whitened by the desulfurization spray washing assembly and the first whitening spray washing assembly, respectively. The desulfurization spraying solution used in the desulfurization spraying assembly is a mixed solution containing sodium sulfide and alkali, wherein the concentration of sodium sulfide in the mixed solution is 1g / L~4g / L and the concentration of alkali in the mixed solution is 1g / L~4g / L; the whitening solution used in the first whitening spraying assembly is a sodium hypochlorite solution, and the cellulose raw material is impregnated with hydrogen peroxide solution during the pretreatment process. The circulation speed of the acid bath fluid in the acid bath tank is 5% to 10% higher than the spinneret speed of the nozzle assembly, and the circulation volume of the acid bath fluid in the acid bath tank is 10m³. 3 ~25m 3 Acid bath circulating fluid / 1m 3 Adhesive.

2. The production process for improving the properties of viscose staple fiber according to claim 1, characterized in that, Each metering pump corresponds to one spindle, the metering pump discharges glue at a rate of 60 mL / rpm to 150 mL / rpm, and the nozzle assembly has 30,000 to 140,000 nozzles per spindle.

3. The production process for improving the properties of viscose staple fiber according to claim 1, characterized in that, The inlet channel at the nozzle front end of the nozzle assembly is a cone-shaped structure with a hyperboloid surface.

4. The production process for improving the properties of viscose staple fiber according to claim 1, characterized in that, The ratio of the nozzle diameter to the nozzle length of the nozzle assembly is 1:(1~5).

5. The production process for improving the properties of viscose staple fiber according to claim 1, characterized in that, The preset depth is 750mm~850mm.

6. The production process for improving the properties of viscose staple fiber according to claim 1, characterized in that, The concentrations of each component in the acid bath circulating solution are: sulfuric acid 70 g / L~150 g / L, sodium sulfate 100 g / L~400 g / L, and zinc sulfate 6 g / L~50 g / L.

7. The production process for improving the properties of viscose staple fiber according to claim 1, characterized in that, It also includes a second whitening spray washing component, in which the filament bundle undergoes whitening treatment by the first whitening spray washing component and then undergoes secondary whitening treatment by the second whitening spray washing component; the whitening solution used in the second whitening spray washing component is a hydrogen peroxide solution.

8. The production process for improving the properties of viscose staple fiber according to claim 7, characterized in that, The concentration of hydrogen peroxide solution used in the second whitening spray washing component is 0.1g / L~2g / L.

9. The production process for improving the properties of viscose staple fiber according to claim 1, characterized in that, The concentration of hydrogen peroxide solution added during the pretreatment process is 0.1 g / L to 2 g / L.

10. The production process for improving the properties of viscose staple fiber according to claim 1, characterized in that, During the process of the adhesive being spun through the nozzle assembly, the degree of expansion of the adhesive is 1% to 3%.

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