阅读说明：本技术 一种高洁净度无纺用粘胶短纤维及其生产方法 (High-cleanliness viscose staple fiber for non-woven and production method thereof ) 是由 李铭远 张浩红 刘岩 张向忠 宋杰 张煜国 韩绍辉 刘海洋 张伟 潘肖 祁保国 于 2021-09-06 设计创作，主要内容包括：本发明涉及一种高洁净度无纺用粘胶短纤维及其生产方法,在粘胶短纤维生产方法的溶解步骤中加入对应甲纤含量0.5％-1％的钛白粉,其主要生产工艺为：将浆粕放入碱液中浸渍后用压榨机压榨粉碎；粉碎后的原料经过老成,加入二硫化碳进行黄化反应生成纤维素磺酸酯,然后加入溶解碱制成粘胶,在溶解过程中加入对应甲纤含量0.5％-1％的钛白粉；再经过熟成、脱泡后,与酸浴反应,经牵伸集束制得再生纤维素纤维,再通过烘干、开松、打包制成成品。本发明较传统高白度再生粘胶短纤维具有低甲醛、均匀性高、产品指标稳定的特点,具有良好的吸湿性、透气性、穿着舒适、无毒、无腐蚀,适用于直接抗疫非织造物,广泛应用于医疗卫生防护领域。(The invention relates to a high-cleanliness viscose staple fiber for non-woven and a production method thereof, wherein titanium dioxide with 0.5-1% of corresponding alpha fiber content is added in the dissolving step of the viscose staple fiber production method, and the main production process comprises the following steps: soaking pulp in alkali liquor, and squeezing and pulverizing with squeezer; aging the crushed raw materials, adding carbon disulfide for yellowing reaction to generate cellulose sulfonate, then adding dissolved alkali to prepare viscose, and adding titanium dioxide with the content of 0.5-1% of corresponding alpha fibers in the dissolving process; and after ripening and defoaming, the mixture reacts with acid bath, the regenerated cellulose fiber is prepared by drafting and bundling, and then the finished product is prepared by drying, opening and packaging. Compared with the traditional high-whiteness regenerated viscose staple fiber, the regenerated viscose staple fiber has the characteristics of low formaldehyde content, high uniformity and stable product index, has good hygroscopicity and air permeability, is comfortable to wear, is non-toxic and non-corrosive, is suitable for direct epidemic-resistant nonwovens, and is widely applied to the field of medical health protection.)

1. A production method of high-cleanliness viscose staple fibers for non-woven fabrics is characterized in that titanium dioxide with the content of corresponding alpha fibers of 0.5-1% is added in the dissolving step of the production method of the viscose staple fibers.

2. The method for producing high-cleanliness non-woven viscose staple fibers according to claim 1, wherein the dissolving step specifically comprises: adding 15-20g/L NaOH solution to prepare light orange viscose, adding titanium dioxide with the content of 0.5-1% corresponding to the alpha fiber when the viscose is discharged to a dissolving machine, dissolving and homogenizing through the dissolving machine, and curing and defoaming to prepare the spinning viscose for spinning.

3. The method for producing high-cleanliness non-woven viscose staple fibers according to claim 2, wherein the step of adding titanium dioxide comprises the following steps: adding titanium dioxide with 0.5-1% of corresponding alpha fiber content and soft water into a titanium dioxide preparation tank, preparing into titanium dioxide solution with the concentration of 200-260g/L, pumping into the titanium dioxide addition tank through a centrifugal pump, and pumping the prepared titanium dioxide solution into a dissolving machine through the centrifugal pump when the viscose is discharged to the dissolving machine.

4. The method for producing high-cleanliness non-woven viscose staple fibers according to claim 3, wherein after the titanium dioxide solution is prepared in a titanium dioxide preparation tank, the titanium dioxide solution is stirred for 60-70 minutes, sampled and detected to be qualified in concentration, and then the titanium dioxide solution is pumped into a titanium dioxide adding tank through a centrifugal pump, if the concentration exceeds a control range, the titanium dioxide solution or soft water is added to adjust the concentration, and then the titanium dioxide solution or the soft water is stirred for 30 minutes for sampling and detection until the concentration is qualified; and a flow meter and a self-control valve are additionally arranged on a titanium dioxide adding pipeline between the titanium dioxide adding tank and the dissolving machine.

5. The method for producing high-cleanliness non-woven viscose staple fibers according to claim 3, wherein the dissolving and homogenizing steps of the dissolving machine are as follows: the dissolving machine is provided with a plurality of fine homogenizers and circulating pumps, the viscose added with the titanium dioxide solution enters the dissolving machine, and the solution is fully dissolved and homogenized in the dissolving machine and the fine homogenizers through 16 cycles of circulating grinding and stirring for 80 minutes by the circulating pumps, so that the titanium dioxide is fully and uniformly mixed in the viscose, and the sol is prepared.

6. The process for producing highly clean non-woven viscose staple fibers according to any one of claims 1 to 5, wherein the process for producing viscose staple fibers comprises the following steps performed in sequence before the dissolving step: soaking, squeezing, aging, and yellowing.

7. The process for producing highly clean non-woven viscose staple fibers according to any one of claims 1 to 5, wherein the process for producing viscose staple fibers comprises the following steps performed in sequence after the dissolving step: spinning, cutting, refining, drying and packaging.

8. The method for producing highly clean viscose staple fibers for nonwoven according to claim 7, wherein in the cutting step, the diameter of the steam pipe at the bottom of the pile forming groove is 2mm, and the number of the holes is 200.

9. The method for producing high-cleanliness non-woven viscose staple fibers according to claim 7, wherein the refining step comprises water washing, desulfurization, secondary water washing, bleaching, hydrogen peroxide water washing, tertiary water washing and oiling, the pH value of the secondary water washing is controlled within the range of 1-3, and the hydrogen peroxide water washing uses 0.5-2g/L hydrogen peroxide to wash the fibers.

10. A high-cleanliness viscose staple fiber for nonwoven produced by the production method as claimed in any one of claims 1 to 9, characterized in that it has a whiteness of more than 93% and a formaldehyde content of less than 6 mg/Kg.

Technical Field

The invention relates to a viscose staple fiber for high-cleanliness non-woven and a production method thereof, belonging to the technical field of non-woven fabrics.

Background

At present, in the production process of domestic viscose staple fiber production enterprises, the method of adding titanium dioxide before viscose spinning is generally adopted to produce high-whiteness viscose staple fibers for medical sanitary materials. Because the traditional process needs to blend powdery titanium dioxide and soft water into a solution with a certain concentration and then add the solution into the spinning glue by filtration, the titanium dioxide has agglomeration in the solution and is not uniformly dispersed in the viscose, so that the finished viscose staple fiber has the defect of unstable index. Secondly, in the traditional process, more sulfide and elemental sulfur are generated in the spinning process and the acid reaction process due to side reaction products of the sulfonation reaction in the viscose production process, and low-valence sulfur cannot be completely removed by refining the traditional desulfurization process, so that the hydrogen sulfide smell is released by the product and hot water or an acid solution after the product is made into a non-woven fabric in the downstream. The refining process is adjusted in the new process, so that the removal capacity of the low-valence sulfur element is improved, the product is free from peculiar smell, and the requirements of downstream non-woven fabric dry towels are met. In addition, on the basis of the prior standard of controlling fiber formaldehyde below 20mg/Kg, the formaldehyde is actually controlled below 6mg/Kg through the improvement of a refining process so as to meet the requirements of some countries on textiles.

Disclosure of Invention

The invention aims to solve the technical problem of providing a high-cleanliness viscose staple fiber for non-woven and a production method thereof, wherein titanium dioxide is added in the viscose dissolving process to prepare the high-cleanliness anti-epidemic viscose staple fiber with good uniformity and stable finished product index, so that the problems of poor uniformity and unstable index in the conventional process for producing the high-whiteness viscose staple fiber are effectively solved, the refining process is improved, the off-flavor of the fiber finished product is reduced, and the formaldehyde content can be reduced.

The technical scheme for solving the technical problems is as follows: a production method of high-cleanliness non-woven viscose staple fibers is characterized in that titanium dioxide with the corresponding alpha fiber content of 0.5% -1% is added in the dissolving step of the production method of the viscose staple fibers. The main production process comprises the following steps: soaking pulp in alkali liquor, and squeezing and pulverizing with squeezer; aging the crushed raw materials, adding carbon disulfide for yellowing reaction to generate cellulose sulfonate, then adding dissolved alkali to prepare viscose, and adding titanium dioxide with the content of 0.5-1% of corresponding alpha fibers in the dissolving process; after ripening and defoaming, the regenerated cellulose fiber is reacted with acid bath, is drafted and bunched to obtain regenerated cellulose fiber, is treated by a new refining process to remove peculiar smell and formaldehyde, and is dried, opened and packaged to obtain a finished product.

The difference between the addition of titanium dioxide in the dissolving step and the addition of titanium dioxide to the spinning solution in the prior art is as follows: the titanium dioxide is added in the dissolving step, so that the titanium dioxide can be more uniformly distributed in the viscose, the titanium dioxide is uniformly mixed in the viscose by utilizing the full grinding and homogenizing effects of a dissolving machine and a fine homogenizer, the agglomeration phenomenon of the titanium dioxide is reduced, and compared with the method of adding the titanium dioxide into the spinning solution, the method is more uniform, and the index of the prepared viscose short fiber is more stable.

The invention has the beneficial effects that: compared with the traditional high-whiteness regenerated viscose staple fibers, the high-cleanliness epidemic-resistance viscose staple fibers produced by the production method have the characteristics of low formaldehyde, high uniformity and stable index, and the product has good hygroscopicity and air permeability, is comfortable to wear, is non-toxic and non-corrosive, is suitable for direct epidemic-resistance nonwovens, and is widely applied to the field of medical health protection.

On the basis of the technical scheme, the invention can be further improved as follows.

Further, the dissolving step specifically comprises: adding 15-20g/L NaOH solution to prepare light orange viscose, adding titanium dioxide with the content of 0.5-1% corresponding to the alpha fiber when the viscose is discharged to a dissolving machine, dissolving and homogenizing through the dissolving machine, and curing and defoaming to prepare the spinning viscose for spinning.

The addition amount of the NaOH solution is determined according to the spinning glue alkali, and the NaOH content in the spinning glue (mass percentage, the same below): 4.9-5.1%, content of alpha-cellulose: 9.3 to 9.5 percent. Theoretical calculation of etiolation plus base: assuming that the input amount of alkali fiber is 7 tons, the composition is 31 percent of the first fiber, the alkali is 16.5 percent, the addition amount of carbon disulfide is 600 liters, the specific gravity is 1.262, the composition of viscose is 8.4 percent of the first fiber, and the alkali is 4.9 percent, the addition amount of the dissolved alkali is as follows: l7000 × 31%/8.4% -7000-.

Further, the step of adding titanium dioxide specifically comprises the following steps: adding titanium dioxide with 0.5-1% of corresponding alpha fiber content and soft water into a titanium dioxide preparation tank, preparing into titanium dioxide solution with the concentration of 200-260g/L, pumping into the titanium dioxide addition tank through a centrifugal pump, and pumping the prepared titanium dioxide solution into a dissolving machine through the centrifugal pump when the viscose is discharged to the dissolving machine.

Further, after the titanium dioxide solution is prepared in a titanium dioxide preparation tank, stirring for 60-70 minutes, sampling, detecting the qualified concentration, and pumping into the titanium dioxide adding tank through a centrifugal pump; if the concentration exceeds the control range, adding titanium dioxide or soft water to adjust the concentration, stirring for 30 minutes, and sampling and testing until the concentration is qualified. .

Furthermore, a flow meter and a self-control valve are additionally arranged on a titanium dioxide adding pipeline between the titanium dioxide adding tank and the dissolving machine.

The prepared titanium dioxide solution is pumped into a dissolving machine and viscose material discharging is carried out simultaneously through a centrifugal pump, and the steps before dissolving are yellowing, so that 1 flow meter and an automatic control valve can be additionally arranged on each titanium dioxide adding pipeline of each dissolving machine and linked with a yellowing system, and automatic control adding of the system is realized.

The titanium dioxide solution is added into the dissolving machine automatically from the titanium dioxide adding tank by adding a self-control valve DCS and compiling an automatic control program in the step of dissolving the viscose.

Further, the dissolving and homogenizing steps of the dissolving machine are as follows: the dissolving machine is provided with a plurality of fine homogenizers and circulating pumps, the viscose added with the titanium dioxide solution enters the dissolving machine, and is ground, stirred, fully dissolved and homogenized in the dissolving machine and the fine homogenizers through 16 cycles of circulation for 80 minutes (which is the circulation time of the dissolving machine set by DCS and reaches the circulation time to be automatically transferred to the next step) by the circulating pumps, so that the titanium dioxide is fully and uniformly mixed in the viscose, and the dissolving glue is prepared.

Further, when the viscose was dissolved for 2800 seconds, a sample was taken to examine the web value and viscosity of the dissolved viscose. Because the viscose light transmittance and the visibility are poor after the titanium dioxide is added, when the falling ball viscosity is measured, the falling ball time cannot be monitored by naked eyes, and the falling ball time is judged by observing the time from the falling ball to the bottom of the viscosity tube through the reflection of a mirror at the bottom of the viscosity tube through multiple experiments. In the process of 16 cycles of circulation within 80 minutes, at 2800 seconds, detecting that the net value is greater than 30S, and the viscosity is within the required range for 90-100S, wherein the purpose of measuring the net value is to see the dissolution effect, and the purpose of measuring the viscosity is to timely adjust according to the viscosity system of the batch, so that the viscosity of the spinning glue reaches the qualified range of 50-70S.

Further, the viscose staple fiber production method comprises the following steps which are sequentially carried out before the dissolving step: soaking, squeezing, aging, and yellowing.

The impregnation step specifically comprises: the pulp after being mixed is put into NaOH solution with the temperature of 50 ℃ and the concentration of 240g/L for soaking for 30-35 minutes.

The squeezing step specifically comprises the following steps: the raw materials are pressed and crushed by a presser, and the bulk weight is 110-140 g/L.

The aging step specifically comprises the following steps: the crushed raw materials are aged at 47-49 ℃ for 100-150 minutes.

The etiolation step specifically comprises the following steps: adding carbon disulfide for yellowing reaction to generate cellulose sulfonate, wherein the adding amount of the carbon disulfide is 30-40% of the content of the corresponding alpha fibers, and the yellowing time is 20-25 minutes.

Further, the viscose staple fiber production method comprises the following steps which are sequentially carried out after the dissolving step: spinning, cutting, refining, drying and packaging.

The subsequent steps after the dissolution step are: the spinning glue is supplied to a bath groove of a spinning and practicing workshop through a pipeline, an acid bath with the concentration of 115-plus 120g/L is supplied to the acid station workshop in the bath groove, the spinning glue is metered by a metering pump and then extruded by a spinning nozzle to form a thin flow, the thin flow enters the acid bath, reacts with sulfuric acid to generate cellulose, is solidified into filaments, is drawn and cut into required length, then various bath liquids are used for leaching viscose staple fibers, and then drying and packaging are carried out.

The original production line in the prior art can not produce high-cleanliness fibers, a titanium dioxide adding system is added before the spinning step after the preparation of a spinning machine is finished according to the traditional production method, the system is injection before spinning, if the equipment modification and the process operation are complicated in the step, a blending tank, a metering tank, a filtering device, a buffer tank and the like are required to be added, and the method has the defects that the uniformity degree of mixing after the titanium dioxide is injected with viscose is insufficient, and the index of finished fibers is unstable.

The spinning steps are specifically as follows: the spinning glue and acid bath with the concentration of 115-one and 120g/L react in a bath tank to produce nascent fiber, and the nascent fiber is subjected to nozzle stretching, godet drafting, two-bath drafting and negative drafting to complete the whole forming process.

The cutting step specifically comprises: the good tows formed after drafting are led into the three-roller cutting-off device through the three-roller, enter the filament inlet nozzle, are tightly held by a water ring formed by cutting-off water, are cut into short fibers with certain length according to certain specifications by a cutter disc and a bed knife which rotate at high speed, are flushed into a fluff forming groove through scouring water, are blown away by bottom steam jet to exert force, and are sent to the next procedure, namely refining. The invention improves the aperture of the steam pipe at the bottom of the fluff forming groove from 4mm to 2mm, improves the number of the holes from 100 holes to 200 holes, and increases the number of the holes by 50 percent.

The refining steps are specifically as follows: the main refining processes include water washing, desulfurizing, secondary water washing, bleaching, hydrogen peroxide washing, tertiary water washing, oiling and the like, and the purpose is to remove or reduce impurities in the fiber which have influence on the product quality and improve the textile performance of the fiber through oiling and softening treatment. The refining process of the invention adjusts the pH value of the secondary water washing between the desulfurization procedure and the bleaching procedure from neutral to pH value of 1-3. The hydrogen peroxide washing procedure is added before the bleaching procedure and the third water washing, and the fiber is washed by using 0.5-2g/L hydrogen peroxide, so that the improvement can remove part of low-valence sulfides in the fiber, remove peculiar smell and reduce the formaldehyde content of the finished product standard detection method to be less than 6 mg/Kg.

In the cutting process, the aperture, the angle and the number of holes of a steam pipe in the fluff forming groove in the original process are changed, and the pressure and the temperature of steam cooked in the fluff forming groove are adjusted, so that the removal rate of hydrogen sulfide in the steaming process of the fluff forming groove is improved. In the refining process and the secondary water washing process, the pH value is changed to be in the range of 1-3, acid-soluble sulfides are removed, and after the bleaching process, a hydrogen peroxide washing process is added to remove the residual hypochlorous acid, partial sulfides and residual formaldehyde in the bleaching process.

The drying and packaging steps are as follows: the refined fiber has a large amount of moisture, and in order to reduce the moisture content to a public standard, the fiber must be dried, the drying process is a relaxation heat setting process of the fiber, the dried fiber is endowed with better hand feeling through fine opening, meanwhile, a large wet block in the fiber is opened, the fiber is more uniform, then the fiber enters a packaging system, and the qualified fiber for measuring the moisture regain after packaging has a warehouse-out condition.

The invention also relates to the high-cleanliness anti-epidemic viscose staple fiber produced by the production method, wherein the whiteness of the high-cleanliness anti-epidemic viscose staple fiber is more than 93 percent, and the formaldehyde content is less than 6 mg/Kg.

Drawings

FIG. 1 is a flow chart of the invention when titanium dioxide is added.

In the drawings, the components represented by the respective reference numerals are listed below:

1. titanium dioxide blending tank, 2 titanium dioxide adding tank, 3 centrifugal pump, 4 flow meter, 5 automatic control valve, 6 dissolving machine.

Detailed Description

The principles and features of this invention are described below in conjunction with examples which are set forth to illustrate, but are not to be construed to limit the scope of the invention.

The invention relates to a production method of high-cleanliness viscose staple fiber for non-woven, which comprises the following steps:

(1) dipping: the pulp after being mixed is put into NaOH solution with the temperature of 50 ℃ and the concentration of 240g/L for soaking for 30-35 minutes.

(2) Squeezing: the raw materials are pressed and crushed by a presser, and the bulk weight is 110-140 g/L.

(3) Aging: the crushed raw materials are aged at 47-49 ℃ for 100-150 minutes.

(4) Yellowing: the addition of carbon disulfide to the first fiber is 30-40%, and the yellowing time is 20-25 min.

(5) Dissolving: adding 15-20g/L NaOH solution to prepare light orange viscose, adding titanium dioxide with the content of 0.5-1% corresponding to the alpha fiber when the viscose is discharged to a dissolving machine 6, dissolving and homogenizing through the dissolving machine 6, and curing and defoaming to prepare spinning glue for spinning, wherein the NaOH content in the spinning glue (mass percentage, the same as below): 4.9-5.1%, content of alpha-cellulose: 9.3 to 9.5 percent.

As shown in fig. 1, with respect to the dissolution step, the following requirements apply:

preparing a titanium dioxide solution: titanium dioxide and soft water with 0.5-1% of alpha fiber content are added into a titanium dioxide preparation tank 1 to prepare a titanium dioxide solution with the concentration of 200-260g/L, after the titanium dioxide solution is stirred for 1 hour and the sampling detection concentration is qualified (if the concentration exceeds the control range, the titanium dioxide or the soft water is added to adjust the concentration, and then the titanium dioxide solution is stirred for 30 minutes and the sampling detection is carried out until the concentration is qualified), the titanium dioxide solution is pumped into a titanium dioxide addition tank 2 through a centrifugal pump 3.

Adding a titanium dioxide solution: during the discharging step of etiolation, the prepared titanium dioxide solution is pumped into a dissolving machine 6 through a centrifugal pump 3. The titanium dioxide adding pipeline of each dissolving machine 6 is additionally provided with 1 flow meter 4 and an automatic control valve 5, and is interlocked with the yellowing system to realize the automatic control of the system.

Taking 14.2 tons of yellow alkali fiber in each batch, 34 percent of the content of the alpha fiber in the alkali fiber and 1 percent of titanium dioxide powder added in the amount of the alpha fiber as an example, the adding amount of the titanium dioxide powder is 14.2 multiplied by 34 percent multiplied by 1 percent which is 0.04828 tons per batch, preparing the titanium dioxide powder into liquid with the concentration of 200g/L, and adding the titanium dioxide powder liquid as follows: 0.04828/0.2X 1000-241.4 l/batch.

Sampling and detecting the viscose network value and viscosity: samples were taken to check the web number and viscosity of the dissolved gum at 2800 seconds after the gum had dissolved. Because the viscose light transmittance and the visibility are poor after the titanium dioxide is added, when the falling ball viscosity is measured, the falling ball time cannot be monitored by naked eyes, and the falling ball time is judged by observing the time from the falling ball to the bottom of the viscosity tube through the reflection of a mirror at the bottom of the viscosity tube through multiple experiments. In the process of 16 cycles of circulation within 80 minutes, at 2800 seconds, detecting that the net value is greater than 30S, and the viscosity is within the required range for 90-100S, wherein the purpose of measuring the net value is to see the dissolution effect, and the purpose of measuring the viscosity is to timely adjust according to the viscosity system of the batch, so that the viscosity of the spinning glue reaches the qualified range of 50-70S.

One dissolving machine 6 can be equipped with 8 fine homogenizers and circulating pumps, the viscose added with the titanium dioxide solution enters the dissolving machine 6, and is homogenized (commonly called grinding), stirred and dissolved into uniform viscose, namely dissolving viscose.

The dissolving machine 6 is a vertical cylinder, a viscose inlet pipe, a viewing mirror and the like are covered on the dissolving machine, an outlet pipe is arranged at the bottom of the dissolving machine, a stirrer is arranged in the dissolving machine, and viscose and titanium dioxide are fully stirred and mixed between the viscose and the titanium dioxide.

The viscose which is not fully dissolved is pumped into 8 fine homogenizers from the bottom of a dissolving machine 6 by a circulating pump (a double-screw pump), is sheared and homogenized by the homogenizers and is pumped back into the dissolving machine 6, and the circulation is carried out for about 16 times, so that the blocky cellulose xanthate is fully ground and crushed between a fixed disc and a rotating disc in the fine homogenizer.

The viscose added with the titanium dioxide is fully homogenized in a dissolving machine 6 and a fine homogenizer by 80 minutes and 16 rounds of circulating grinding and stirring, so that the titanium dioxide is fully and uniformly mixed in the viscose.

The dissolved glue fully stirred and homogenized by the dissolver 6 and the fine homogenizer is aged and defoamed to prepare the spinning glue for spinning.

(6) Spinning: the spinning glue and acid bath with the concentration of 115-one and 120g/L react in a bath tank to produce nascent fiber, and the nascent fiber is subjected to nozzle stretching, godet drafting, two-bath drafting and negative drafting to complete the whole forming process.

(7) Cutting: the good tows formed after drafting are led into the three-roller cutting-off device through the three-roller, enter the filament inlet nozzle, are tightly held by a water ring formed by cutting-off water, are cut into short fibers with certain length according to certain specifications by a cutter disc and a bed knife which rotate at high speed, are flushed into a fluff forming groove through scouring water, are blown away by bottom steam jet to exert force, and are sent to the next procedure, namely refining. The invention improves the aperture of the steam pipe at the bottom of the fluff forming groove from 4mm to 2mm, improves the number of the holes from 100 holes to 200 holes, and increases the number of the holes by 50 percent.

(8) Refining: the main refining processes include water washing, desulfurizing, secondary water washing, bleaching, hydrogen peroxide washing, tertiary water washing, oiling and the like, and the purpose is to remove or reduce impurities in the fiber which have influence on the product quality and improve the textile performance of the fiber through oiling and softening treatment. The refining process of the invention adjusts the pH value of the secondary water washing between the desulfurization procedure and the bleaching procedure from neutral to pH value of 1-3. The hydrogen peroxide washing procedure is added before the bleaching procedure and the third water washing, and the fiber is washed by using 0.5-2g/L hydrogen peroxide, so that the improvement can remove part of low-valence sulfides in the fiber, remove peculiar smell and reduce the formaldehyde content of the finished product standard detection method to be less than 6 mg/Kg.

(9) Drying and packaging: the refined fiber has a large amount of moisture, and in order to reduce the moisture content to a public standard, the fiber must be dried, the drying process is a relaxation heat setting process of the fiber, the dried fiber is endowed with better hand feeling through fine opening, meanwhile, a large wet block in the fiber is opened, the fiber is more uniform, then the fiber enters a packaging system, and the qualified fiber for measuring the moisture regain after packaging has a warehouse-out condition.

The whiteness of the viscose staple fiber produced by the method is more than 93 percent, and the formaldehyde content reaches below 6 mg/Kg.

Example 1

A high-cleanliness anti-epidemic viscose staple fiber and a production process thereof comprise the following steps:

(1) dipping: the pulp after being mixed is put into NaOH solution with the temperature of 50 ℃ and the concentration of 240g/L for soaking for 30 minutes.

(2) Squeezing: the raw materials are pressed and crushed by a presser, and the volume weight is determined to be 110 g/L.

(3) Aging: the crushed raw materials are aged for 100 minutes at 47 ℃.

(4) Yellowing: the addition amount of carbon disulfide to the methyl fiber is 30 percent, and the yellowing time is 20 minutes.

(5) Dissolving: adding 15g/L NaOH solution to prepare light orange viscose, adding titanium dioxide with 0.5 percent of corresponding alpha fiber content when the viscose is discharged to a dissolving machine 6 (firstly, adding the titanium dioxide with 0.5 percent of the alpha fiber content and soft water into a titanium dioxide blending tank 1 to blend into a titanium dioxide solution with the concentration of 200g/L, adding the titanium dioxide solution into the dissolving machine 6), dissolving and homogenizing by the dissolving machine 6, curing and defoaming to prepare spinning glue for spinning, wherein the NaOH content in the spinning glue (mass percent, the same below): 4.9%, content of alpha-cellulose: 9.3 percent.

(6) Spinning: the spinning glue and acid bath with the concentration of 115g/L react in a bath tank to produce nascent fiber, and the nascent fiber is subjected to nozzle stretching, godet drafting, two-bath drafting and negative drafting to complete the whole forming process.

(7) Cutting: the good tows formed after drafting are led into the three-roller cutting-off device through the three-roller, enter the filament inlet nozzle, are tightly held by a water ring formed by cutting-off water, are cut into short fibers with certain length according to certain specifications by a cutter disc and a bed knife which rotate at high speed, are flushed into a fluff forming groove through scouring water, are blown away by bottom steam jet to exert force, and are sent to the next procedure, namely refining. The diameter of the steam pipe at the bottom of the fluff forming groove is 2mm, and the number of the holes is 200.

(8) Refining: the main refining processes include water washing, desulfurizing, secondary water washing, bleaching, hydrogen peroxide washing, tertiary water washing, oiling and the like, and the purpose is to remove or reduce impurities in the fiber which have influence on the product quality and improve the textile performance of the fiber through oiling and softening treatment. The pH value control range of the secondary water washing is 1-3, and the hydrogen peroxide water washing uses 0.5-2g/L hydrogen peroxide to wash the fibers.

(9) Drying and packaging: the refined fiber has a large amount of moisture, and in order to reduce the moisture content to a public standard, the fiber must be dried, the drying process is a relaxation heat setting process of the fiber, the dried fiber is endowed with better hand feeling through fine opening, meanwhile, a large wet block in the fiber is opened, the fiber is more uniform, then the fiber enters a packaging system, and the qualified fiber for measuring the moisture regain after packaging has a warehouse-out condition.

Example 2

A high-cleanliness anti-epidemic viscose staple fiber and a production process thereof comprise the following steps:

(1) dipping: the pulp after being mixed is put into NaOH solution with the temperature of 50 ℃ and the concentration of 240g/L for soaking for 32 minutes.

(2) Squeezing: the raw materials are pressed and crushed by a presser, and the volume weight is determined to be 125 g/L.

(3) Aging: the crushed raw materials are aged for 125 minutes at 48 ℃.

(4) Yellowing: the addition of carbon disulfide to the methyl fiber is 35 percent, and the yellowing time is 23 minutes.

(5) Dissolving: adding 18g/L NaOH solution to prepare light orange viscose, adding titanium dioxide with the corresponding alpha fiber content of 0.8% when the viscose is discharged to a dissolving machine 6 (firstly, adding the titanium dioxide with the corresponding alpha fiber content of 0.8% and soft water into a titanium dioxide blending tank 1, blending into a titanium dioxide solution with the concentration of 230g/L, adding the titanium dioxide solution into the dissolving machine 6), dissolving and homogenizing by the dissolving machine 6, curing and defoaming to prepare spinning glue for spinning, wherein the NaOH content in the spinning glue (mass percentage, the same below): 5.0%, alpha-fiber content: 9.4 percent.

(6) Spinning: the spinning glue and 118g/L acid bath react in a bath tank to produce nascent fiber, and the nascent fiber is subjected to nozzle stretching, godet drafting, two-bath drafting and negative drafting to complete the whole forming process.

(7) Cutting: the good tows formed after drafting are led into the three-roller cutting-off device through the three-roller, enter the filament inlet nozzle, are tightly held by a water ring formed by cutting-off water, are cut into short fibers with certain length according to certain specifications by a cutter disc and a bed knife which rotate at high speed, are flushed into a fluff forming groove through scouring water, are blown away by bottom steam jet to exert force, and are sent to the next procedure, namely refining. The diameter of the steam pipe at the bottom of the fluff forming groove is 2mm, and the number of the holes is 200.

(8) Refining: the main refining processes include water washing, desulfurizing, bleaching, oiling, etc. and aims at eliminating or reducing impurity in fiber and improving the spinning performance of fiber through oiling and softening treatment. The pH value control range of the secondary water washing is 1-3, and the hydrogen peroxide water washing uses 0.5-2g/L hydrogen peroxide to wash the fibers.

(9) Drying and packaging: the refined fiber has a large amount of moisture, and in order to reduce the moisture content to a public standard, the fiber must be dried, the drying process is a relaxation heat setting process of the fiber, the dried fiber is endowed with better hand feeling through fine opening, meanwhile, a large wet block in the fiber is opened, the fiber is more uniform, then the fiber enters a packaging system, and the qualified fiber for measuring the moisture regain after packaging has a warehouse-out condition.

Example 3

A high-cleanliness anti-epidemic viscose staple fiber and a production process thereof comprise the following steps:

(1) dipping: the pulp after being mixed is put into NaOH solution with the temperature of 50 ℃ and the concentration of 240g/L for soaking for 35 minutes.

(2) Squeezing: the raw materials are pressed and crushed by a presser, and the volume weight is determined to be 140 g/L.

(3) Aging: the crushed raw materials are aged for 150 minutes at 49 ℃.

(4) Yellowing: the addition amount of carbon disulfide to the methyl fiber is 40 percent, and the yellowing time is 25 minutes.

(5) Dissolving: adding 20g/L NaOH solution to prepare light orange viscose, adding titanium dioxide with the content of corresponding alpha fibers of 1 percent when the viscose is discharged to a dissolving machine 6 (firstly, adding the titanium dioxide with the content of 1 percent of the alpha fibers and soft water into a titanium dioxide blending tank 1, blending into a titanium dioxide solution with the concentration of 260g/L, adding the titanium dioxide solution into the dissolving machine 6), dissolving and homogenizing by the dissolving machine 6, curing and defoaming to prepare spinning glue for spinning, wherein the NaOH content in the spinning glue (mass percent, the same below): 5.1%, content of alpha-cellulose: 9.5 percent.

(6) Spinning: the spinning glue and the acid bath with the concentration of 120g/L react in a bath tank to produce nascent fiber, and the nascent fiber is subjected to nozzle stretching, godet drafting, two-bath drafting and negative drafting to complete the whole forming process.

(7) Cutting: the good tows formed after drafting are led into the three-roller cutting-off device through the three-roller, enter the filament inlet nozzle, are tightly held by a water ring formed by cutting-off water, are cut into short fibers with certain length according to certain specifications by a cutter disc and a bed knife which rotate at high speed, are flushed into a fluff forming groove through scouring water, are blown away by bottom steam jet to exert force, and are sent to the next procedure, namely refining. The diameter of the steam pipe at the bottom of the fluff forming groove is 2mm, and the number of the holes is 200.

(8) Refining: the main refining processes include water washing, desulfurizing, secondary water washing, bleaching, hydrogen peroxide washing, tertiary water washing, oiling and the like, and the purpose is to remove or reduce impurities in the fiber which have influence on the product quality and improve the textile performance of the fiber through oiling and softening treatment. The pH value control range of the secondary water washing is 1-3, and the hydrogen peroxide water washing uses 0.5-2g/L hydrogen peroxide to wash the fibers.

(9) Drying and packaging: the refined fiber has a large amount of moisture, and in order to reduce the moisture content to a public standard, the fiber must be dried, the drying process is a relaxation heat setting process of the fiber, the dried fiber is endowed with better hand feeling through fine opening, meanwhile, a large wet block in the fiber is opened, the fiber is more uniform, then the fiber enters a packaging system, and the qualified fiber for measuring the moisture regain after packaging has a warehouse-out condition.

Comparative example 1

Similar to the steps of the above embodiment, except that no titanium dioxide is added in the preparation process.

Comparative example 2

Similar to the steps of the above embodiment, the difference is that titanium dioxide is not added during the dissolution in the step (5), but titanium dioxide is added into the spinning glue before the spinning in the step (6) after the spinning glue for spinning is prepared in the step (5). And (4) spraying steam in the fluff forming groove in the step (7) to form a hole with the diameter of 4mm, wherein the number of the holes is 100. And (4) performing neutral control of water washing between the desulfurization and the bleaching in the step (8), wherein a hydrogen peroxide washing procedure is not added after bleaching.

The whiteness, defects, formaldehyde content and odor of the viscose staple fibers prepared in the above examples and comparative examples were measured.

Comparative example 1 compared with examples 1 to 3, the addition of titanium dioxide in the dissolution step without titanium dioxide is compared: the whiteness of the viscose staple fibers prepared without adding titanium dioxide in comparative example 1 is 89% -90%, the whiteness of the viscose staple fibers prepared by adding titanium dioxide in the dissolving step in examples 1-3 is more than 93%, generally 94% -95%, and the whiteness of the viscose staple fibers obtained in examples 1-3 is higher, so that the viscose staple fibers are more suitable for medical sanitary materials.

Comparative example 2 compared with examples 1-3, the addition of titanium dioxide in the spinning dope was compared with the addition of titanium dioxide in the dissolving step: comparative example 2 the viscose staple fiber made by adding titanium dioxide into the spinning dope has poor index stability, such as the defect is higher by 2.0mg/Kg, the fineness variation coefficient is higher by more than 11%, etc., the viscose staple fiber made by adding titanium dioxide in the dissolving step in examples 1-3 has high index stability, such as the defect is lower than 1.0mg/Kg, the fineness variation coefficient is reduced to below 8%, the finished high-whiteness fiber of comparative example 2 has peculiar smell of hydrogen sulfide after being soaked in hot water at 60 ℃ or citric acid solution with the mass fraction of 10%, and the formaldehyde content is 15-19 mg/Kg. The viscose staple fibers obtained in the embodiments 1 to 3 have high index stability and high uniformity, the formaldehyde content is 3 to 5.5mg/Kg, the formaldehyde content is lower, and the viscose staple fibers have good hygroscopicity and air permeability, are comfortable to wear, are non-toxic, non-corrosive and odorless, are suitable for direct epidemic-resistant nonwovens, can be widely applied to the field of medical and health protection, and are superior to viscose staple fibers produced by the prior art.

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, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.