Wood source type flat cellulose short fiber and production method thereof

Abstract

The invention relates to the technical field of viscose fiber preparation, and particularly discloses a wood-source type flat cellulose short fiber and a production method thereof.The wood-source type flat cellulose short fiber comprises a spinning solution, the spinning solution is subjected to spinning and aftertreatment in an acid bath through a tantalum nozzle with flat spinneret orifices, and the flat cellulose short fiber is prepared. The spinning solution comprises the following raw materials: 8.8-9.2% of alpha cellulose, 4.8-5.2% of alkali liquor and the balance of a pretreated lignocellulose raw material, the spinning solution mainly comprises the alpha cellulose, the alkali liquor and the pretreated lignocellulose raw material, and then the spinning solution is subjected to spinning and post-treatment in an acid bath through a tantalum nozzle to prepare the flat cellulose short fiber. The tantalum nozzle with the flat spinneret orifices is adopted, so that the production cost is reduced, the service life of the nozzle is prolonged, and meanwhile, the flatness rate of the fibers is larger than or equal to 95%.

Description

Technical Field

[0001] The invention belongs to the technical field of viscose fiber preparation, and specifically relates to a wood-derived flat cellulose staple fiber and a production method thereof. Background Art

[0002] The cross section of traditional viscose fiber is irregularly round, the fiber surface has weak gloss and waxy feeling, and its fabric has the disadvantages of easy to get dirty, easy to pilling, poor water absorption, and small coverage. After the fiber cross section is deformed, the gloss, bulkiness, hygroscopicity, anti-pilling, pilling, stain resistance, stiffness, elasticity and hand feel of the fiber textile can be improved to varying degrees. Among them, the flat fiber cross section has a large number of space air pockets in its fabric, which can resist the strong attack of cold, has a certain degree of warmth retention, and good moisture absorption and breathability.

[0003] At present, the production of flat viscose fibers mainly adopts the method of special-shaped spinneret holes and bulking adhesion method. For example, patent document 1 with application number CN201310512343.1 discloses a method for producing flat viscose fibers and a tantalum nozzle used in the production process. The flat viscose staple fibers are made of cotton, wood, and bamboo pulp. The method includes the following steps: preparing alkali cellulose, preparing spinning solution, preparing spinning bath, preparing primary filaments, drawing, cutting, and post-processing. The tantalum nozzle used in the production process is a rectangular nozzle combination tantalum nozzle, which is an annular structure as a whole, and the shape of the nozzle of the spinneret cap is rectangular. The present invention uses a combination tantalum nozzle with a special arrangement of rectangular holes, adjusts the process parameters of the spinning solution and the spinning bath, and adjusts the draft distribution. The fabric produced by the 25-150mm flat viscose staple fibers has obvious warming effect, is comfortable to wear, and is particularly suitable for winter underwear. Sanitary napkins or paper products made of 3-15mm ultra-short flat viscose fibers can be flushed away after use, and are of the type that disperses immediately after flushing, which reduces the amount of water used for flushing and accelerates the degradation process. Products for both uses are superior to existing products.

[0004] For example, patent document 2, application number CN201210156190.7, discloses a sheet-like flat viscose fiber and a preparation method thereof, the method comprising: 1) adding a carbonate solution to a viscose solution after yellowing, and mixing the solution evenly with the viscose solution to obtain a mixed spinning viscose, wherein the amount of carbonate added is 30 to 50 wt% of the methyl fiber in the cellulose viscose. (2) The mixed spinning viscose is spun into shape through a coagulation bath. (3) The spun fibers after forming are subjected to a jet drawing, wherein the drawing rate of the jet drawing is 30 to 60%, and then the sheet-like flat viscose fiber is obtained through plasticizing drawing and post-processing steps. The present invention can achieve the imitation of flat viscose fibers without using a spinneret with a specific nozzle shape, thus breaking the traditional production mode of flat viscose fibers and being a revolution in the production of special-shaped viscose fibers. Moreover, compared with the prior art, the present invention reduces equipment investment and is easy to realize industrial production.

[0005] However, the above patent documents still have the following defects:

[0006] 1. Although patent document 1 uses gold, platinum and rhodium to prepare tantalum nozzles, the raw materials are relatively soft, easily deformed during the production process, have a short service life, and are relatively expensive. In addition, the document does not mention the fiber flatness;

[0007] 2. Patent Document 2 adopts the puffing adhesion method, which adds carbonate solution, resulting in increased costs and reduced fiber strength, which is not conducive to industrial production;

[0008] In order to solve the above-mentioned defects, we need to propose a wood-derived flat cellulose staple fiber and a production method thereof. By adopting a tantalum nozzle, the production cost is reduced, the service life of the nozzle is extended, and the fiber flatness is ≥95%. Summary of the invention

[0009] The purpose of the present invention is to provide a wood-derived flat cellulose staple fiber and a production method thereof, which adopts a tantalum nozzle to reduce production costs and extend the service life of the nozzle. At the same time, the fiber flatness is ≥95% to solve the problems raised in the above background technology.

[0010] To achieve the above object, the present invention adopts the following technical solutions:

[0011] A wood-derived flat cellulose staple fiber comprises a spinning solution, wherein the spinning solution is spun in an acid bath through a tantalum nozzle having a flat spinneret hole and then post-treated to obtain the flat cellulose staple fiber. The spinning solution comprises the following raw materials by mass percentage: 8.8-9.2% of methyl cellulose, 4.8-5.2% of alkali solution, and the remainder is pre-treated wood cellulose raw material.

[0012] Preferably, the spinning solution comprises the following raw materials: 9% methyl cellulose, 5% alkali solution, and the remainder is pretreated lignocellulose raw material.

[0013] Preferably, the alkali solution is set to sodium hydroxide or potassium hydroxide, and the pH value of the alkali solution is set to 12-14.

[0014] Preferably, the acid solution used in the acid bath is sulfuric acid and zinc sulfate, the concentration of the sulfuric acid is 100-120 g / L, the concentration of zinc sulfate is 10-20 g / L, the specific gravity of the acid bath is 1.180-1.250 Kg / L, and the temperature of the acid bath is 48-55°C.

[0015] Preferably, the spinning solution has a spinning viscosity of 40-60 seconds and a young rubber maturity of 8-14 mL.

[0016] Preferably, during spinning, the spinning speed is 48-65 m / min and the drawing rate is 60-80%.

[0017] Based on the above-described wood-derived flat cellulose staple fibers, the present invention further provides a method for producing wood-derived flat cellulose staple fibers, comprising the following steps:

[0018] S1, spinning solution is spun in an acid bath through a tantalum nozzle having a flat spinneret hole to form regenerated fiber;

[0019] S2, post-treating the regenerated fiber to obtain treated regenerated fiber, wherein the post-treatment includes washing, desulfurization, bleaching and oiling;

[0020] S3, drying the treated regenerated fibers to obtain flat fibers.

[0021] Preferably, during washing, the regenerated fiber is rinsed with clean water, and the number of rinses is divided into three levels of washing to ensure thorough washing. A large amount of water is used in each level of washing to ensure sufficient washing. The fiber then enters a dehydrator for dehydration treatment, and the washing temperature of each level is 60-80°C.

[0022] Preferably, during desulfurization, the regenerated fiber is placed in a solution containing a desulfurizer, sulfides are converted into soluble sulfur compounds through chemical reactions, and then washed again with water, the desulfurization temperature is 70-90°C, the concentration is 1.0-3.0g / L, and the residual sulfur is ≤5.0mg / 100g.

[0023] Based on the above-described method for producing a wood-derived flat cellulose staple fiber, the present invention further provides a spinneret for producing a wood-derived flat cellulose staple fiber, comprising a spinneret and a flower plate, wherein the spinneret is inlaid on the flower plate to form a combined tantalum spinneret, and a plurality of flat spinneret holes are arranged on the spinneret, wherein the number of the spinneret holes is 500-900, and the aspect ratio of the spinneret holes is 8-10:1.

[0024] The wood-derived flat cellulose staple fiber and the production method thereof proposed in the present invention have the following advantages compared with the prior art:

[0025] 1. The present invention mainly comprises a spinning solution consisting of methyl cellulose, alkali solution and pre-treated wood cellulose raw materials, and then the spinning solution is spun in an acid bath through a tantalum nozzle and post-treated to obtain flat cellulose staple fibers, so that the spun fibers produce many air pockets that can effectively isolate cold air and improve the warmth retention of the fibers. By adopting a tantalum nozzle with a flat spinneret hole, the production cost is reduced, the service life of the nozzle is extended, and the fiber flatness rate is ≥95%. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a flowchart of the present invention;

[0027] Figure 2 It is a schematic diagram of the structure of the tantalum nozzle of the present invention;

[0028] Figure 3 It is a schematic diagram of the spinneret hole structure of the present invention;

[0029] Figure 4 This is a cross-sectional view of the flat cellulose staple fiber prepared in the present invention;

[0030] In the figure: 1. spinneret; 2. flower plate; 3. spinneret hole. DETAILED DESCRIPTION

[0031] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0032] Example 1

[0033] The present invention provides Figure 1 The wood-derived flat cellulose staple fiber shown includes a spinning solution, which is spun in an acid bath through a tantalum nozzle having a flat spinneret hole and post-treated to obtain the flat cellulose staple fiber. The spinning solution includes the following raw materials by mass percentage: 9% methyl cellulose, 5% alkali solution, and the remainder is pre-treated wood cellulose raw material.

[0034] The alkali solution is set to sodium hydroxide or potassium hydroxide, and the pH value of the alkali solution is set to 12-14. In the spinning solution, the alkali solution is used to dissolve cellulose or other polymer substances to form a viscous solution suitable for spinning;

[0035] The spinning glue viscosity of the spinning solution is 40-60 seconds, and the maturation degree of the young glue is 8-14mL, wherein the spinning glue viscosity refers to the viscosity of the spinning glue (colloid solution for spinning), that is, the ability of the internal molecules to resist shearing. The viscosity of 40-60 seconds means that under certain conditions (such as certain temperature, pressure, etc.), the time required for a certain amount of spinning glue to flow out of a standard container is between 40 and 60 seconds. This range ensures that the spinning glue has appropriate fluidity, which can not only ensure the continuous molding of the fiber, but also maintain the mechanical properties of the fiber.

[0036] The maturity of viscose refers to the degree of maturity reached by viscose (a solution formed by dissolving cellulose or other high molecular weight substances in a solvent) after a certain period of aging under certain conditions. The maturity of 8-14mL usually indicates the solidification amount or gelation degree of the viscose solution measured by a certain method. The proper control of maturity is crucial to the spinning process, which directly affects the spinning quality, including the uniformity and mechanical properties of the fiber. If the maturity is too low, the fiber strength will be insufficient and uneven; if the maturity is too high, it may lead to spinning difficulties and an increase in the rate of broken fibers.

[0037] The acid used in the acid bath is sulfuric acid and zinc sulfate, and the viscose thin stream just out of the spinneret hole is used in the acid bath to slowly and evenly solidify and form, forming a regenerated fiber with an approximate full cortex structure, the concentration of the sulfuric acid is 100-120g / L, the concentration of zinc sulfate is 10-20g / L, the acid bath specific gravity is 1.180-1.250Kg / L, and the acid bath temperature is 48-55°C. The combination of sulfuric acid and zinc sulfate can accelerate the rapid solidification of the viscose solution after the spinneret is extruded to form fibers, and by controlling the concentration of sulfuric acid and zinc sulfate in the acid bath, it can be ensured that the fibers are more uniform during the coagulation process, thereby improving the overall quality of the fibers, and spinning in an acid bath of sulfuric acid and zinc sulfate can effectively improve the strength and toughness of the regenerated fibers. This is because suitable acid bath conditions help to form more compact and orderly fiber knots, and the treatment of sulfuric acid and zinc sulfate can increase the whiteness and gloss of the fibers, so that the final product has better market competitiveness.

[0038] During spinning, the spinning speed is 48-65m / min and the draft rate is 60-80%. This spinning speed can speed up the fiber forming process, thereby improving the output capacity of the production line. By controlling the draft rate at 60-80%, the fiber breakage rate during the forming process can be significantly reduced, which helps to reduce downtime in the production process and improve overall production efficiency.

[0039] Based on the above-described wood-derived flat cellulose staple fibers, the present invention further provides a method for producing wood-derived flat cellulose staple fibers, comprising the following steps:

[0040] S1, spinning solution is spun in an acid bath through a tantalum nozzle having a flat spinneret hole to form regenerated fiber;

[0041] S2, post-treating the regenerated fiber to obtain treated regenerated fiber, wherein the post-treatment includes washing, desulfurization, bleaching and oiling;

[0042] S3, drying the treated regenerated fibers to obtain flat fibers.

[0043] Among them, during washing, the regenerated fiber is rinsed with clean water, and the washing times are divided into three levels to ensure thorough washing. A large amount of water is used in each level to ensure sufficient washing. After that, the fiber enters the dehydrator for dehydration treatment. The washing temperature of each level is 60-80℃.

[0044] During desulfurization, the regenerated fiber is placed in a solution containing a desulfurizer, sulfide is converted into soluble sulfur compounds through chemical reaction, and then washed again. The desulfurization temperature is 70-90°C, the concentration is 1.0-3.0g / L, and the residual sulfur is ≤5.0mg / 100g.

[0045] When bleaching, use bleaching agents such as hydrogen peroxide or sodium hypochlorite, soak the fiber in the bleaching solution, remove pigments and impurities through oxidation reaction, and then wash thoroughly after the reaction is completed. The bleaching temperature is 55-70℃ and the concentration is 0.5-1.2g / L;

[0046] When oiling, the fiber is passed through a solution containing a special oil agent. The oil agent will evenly adhere to the fiber surface to form a protective film. Then, excess water and solution are removed by squeezing or drying to ensure that the oil agent is evenly distributed and fixed on the fiber surface. The oiling temperature is 60-70℃, the pH value is 4-6, and the oiling rate is 0.01-0.08%.

[0047] The engineering and technical personnel in charge of on-site operations adjust the process parameters of each process within the set range according to the actual situation of each production, match the spinning process, and draw on the mature process of viscose fiber for flat fiber production, sharing the existing viscose production resources.

[0048] Based on the above-described method for producing wood-derived flat cellulose staple fibers, the present invention also provides a spinneret for producing wood-derived flat cellulose staple fibers, such as Figure 2-3 As shown, it includes a spinneret 1 and a flower plate 2, the spinneret 1 is inlaid on the flower plate 2 to form a combined tantalum spinneret, the spinneret 1 is provided with a plurality of flat spinneret holes 3, the number of the spinneret holes 3 is 500-900, the aspect ratio of the spinneret holes 3 is 8-10:1, the spinneret size is 720 holes × 0.25mm × 0.025mm, and the appearance is no different from the traditional combined spinneret, which is composed of the spinneret 1 inlaid on the flower plate 2, as shown in FIG. Figure 2 As shown, the difference is that the inner diameter of the nozzle hole of the flat spinneret 1 is not a traditional circle, but a flat shape, such as Figure 3 shown.

[0049] The fiber cortex thickness and surface area are increased by using a flat tantalum nozzle and a low-acid, high-zinc, high-drafting process. The spun fiber produces many air pockets that can effectively isolate cold air, eliminating the shortcomings of traditional viscose fibers in terms of warmth retention.

[0050] Example 2

[0051] The similarities are not repeated here. The difference from Example 1 is that it includes a spinning solution, which is spun in an acid bath through a tantalum nozzle having a flat spinneret hole and post-treated to obtain flat cellulose staple fibers. The spinning solution includes the following raw materials, by mass percentage: 8.8% acetone, 4.8% alkali solution, and the remainder is pre-treated wood cellulose raw material, so that the spun fibers produce many air pockets that can effectively isolate cold air and improve the warmth retention of the fibers.

[0052] Example 3

[0053] The similarities are not repeated here. The difference from Example 1 is that it includes a spinning solution, which is spun in an acid bath through a tantalum nozzle having a flat spinneret hole and post-treated to obtain flat cellulose staple fibers. The spinning solution includes the following raw materials by mass percentage: 9.2% acetone, 5.2% alkali solution, and the remainder is pre-treated wood cellulose raw material, so that the spun fibers produce many air pockets that can effectively isolate cold air and improve the warmth retention of the fibers.

[0054] Example 4

[0055] According to the methods provided in Example 1, Example 2 and Example 3, the flat cellulose staple fibers respectively obtained were subjected to flatness test and thermal conductivity test; thermal conductivity is an important indicator to measure the thermal conductivity of fiber materials, which indicates the rate of heat transfer through a unit area (1 square meter) under unit thickness (1 meter) and unit temperature difference (1 degree Celsius). The lower the thermal conductivity, the better the thermal insulation performance of the material, and thus the stronger the warmth retention. Fibers with good warmth retention performance, such as wool, acrylic and some viscose fibers, generally have a thermal conductivity of about 0.05W / (m·K) or lower. This is because the internal structure and voids of these fibers can effectively limit the transfer of heat.

[0056] The test results are shown in the following table:

[0057]

[0058] It can be concluded from the above table data that the flat cellulose staple fibers prepared by the methods provided in Examples 1, 2 and 3 have a fiber flatness of more than 95% and an average thermal conductivity of between 0.02 and 0.04, indicating that the flat cellulose staple fibers have a strong thermal insulation effect.

[0059] In summary, the flat cellulose staple fibers are obtained by spinning a spinning solution mainly composed of methyl cellulose, alkali solution and pretreated wood cellulose raw materials, and then spinning and post-treating the spinning solution in an acid bath through a tantalum nozzle. The spun fibers produce many air pockets that can effectively isolate the cold air and improve the warmth retention of the fibers. By adopting a tantalum nozzle with a flat spinneret hole, the production cost is reduced, the service life of the nozzle is extended, and the fiber flatness rate is ≥95%.

[0060] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A wood-derived flat cellulose staple fiber, characterized in that: The invention comprises a spinning solution, wherein the spinning solution is spun in an acid bath through a tantalum nozzle having a flat spinneret hole and then post-treated to obtain flat cellulose short fibers. The spinning solution comprises the following raw materials by mass percentage: 8.8-9.2% methyl cellulose, 4.8-5.2% alkali solution, and the remainder is pre-treated wood cellulose raw material.

2. The wood-derived flat cellulose short fiber according to claim 1, characterized in that: The spinning solution comprises the following raw materials: 9% methyl cellulose, 5% alkali solution, and the remainder is pre-treated wood cellulose raw material.

3. The wood-derived flat cellulose short fiber according to claim 2, characterized in that: The alkali solution is set to sodium hydroxide or potassium hydroxide, and the pH value of the alkali solution is set to 12-14.

4. The wood-derived flat cellulose short fiber according to claim 3, characterized in that: The acid solution used in the acid bath is sulfuric acid and zinc sulfate, the concentration of the sulfuric acid is 100-120 g / L, the concentration of zinc sulfate is 10-20 g / L, the specific gravity of the acid bath is 1.180-1.250 Kg / L, and the temperature of the acid bath is 48-55°C.

5. The wood-derived flat cellulose staple fiber according to claim 4, characterized in that: The spinning solution has a spinning viscosity of 40-60 seconds and a young rubber maturity of 8-14 mL.

6. The wood-derived flat cellulose staple fiber according to claim 5, characterized in that: During spinning, the spinning speed is 48-65 m / min and the drawing rate is 60-80%.

7. A method for producing wood-derived flat cellulose staple fibers, based on the wood-derived flat cellulose staple fibers according to any one of claims 1 to 6, characterized in that: The steps include: S1, spinning solution is spun in an acid bath through a tantalum nozzle having a flat spinneret hole to form regenerated fiber; S2, post-treating the regenerated fiber to obtain treated regenerated fiber, wherein the post-treatment includes washing, desulfurization, bleaching and oiling; S3, drying the treated regenerated fibers to obtain flat fibers.

8. The method for producing wood-derived flat cellulose staple fibers according to claim 7, characterized in that: During washing, the regenerated fiber is rinsed with clean water. The rinsing times are divided into three levels to ensure thorough cleaning. A large amount of water is used in each level to ensure sufficient cleaning. After that, the fiber enters the dehydrator for dehydration. The washing temperature of each level is 60-80℃.

9. The method for producing wood-derived flat cellulose staple fibers according to claim 8, characterized in that: During desulfurization, the regenerated fiber is placed in a solution containing a desulfurizer, sulfide is converted into soluble sulfur compounds through chemical reaction, and then washed again. The desulfurization temperature is 70-90°C, the concentration is 1.0-3.0g / L, and the residual sulfur is ≤5.0mg / 100g.

10. A spinneret for producing wood-derived flat cellulose staple fibers, based on the method for producing wood-derived flat cellulose staple fibers according to claim 7, characterized in that: The invention comprises a spinneret (1) and a flower plate (2), wherein the spinneret (1) is inlaid on the flower plate (2) to form a combined tantalum spinneret, and the spinneret (1) is provided with a plurality of flat spinneret holes (3), the number of the spinneret holes (3) is 500-900, and the length-to-width ratio of the spinneret holes (3) is 8-10:1.

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