Polylactic acid and viscose fiber wrapped yarn and preparation method and application thereof

Abstract

The invention belongs to the field of spinning, and discloses a polylactic acid and viscose fiber wrapped yarn and a preparation method and application thereof. According to the preparation method, viscose fiber roving and polylactic acid filaments are used as raw materials, and polylactic acid and viscose fiber wrapped yarn is obtained by adopting a long-short wrapping composite spinning process; the quantity of the viscose fiber roving is 2.6-3.0 g / 10m, and the twist coefficient is 65-75; the mass ratio of the viscose fiber roving to the polylactic acid filaments is (10-45): (55-90). By utilizing the wrapping structure of the viscose staple fibers and the polylactic acid filaments and the cohesion among the fibers, the slippage of the staple fibers can be reduced, the yarn strength can be increased, the yarn hairiness can be reduced, the weaving efficiency can be improved, and the characteristics of wear resistance, fuzzing and pilling resistance and the like of the fabric can be further improved. Therefore, the high-strength wear-resistant effect of the polylactic acid blended yarn is achieved, and meanwhile good wearing comfort and environment friendliness of a textile product are guaranteed.

Description

Technical Field

[0001] The invention relates to the field of textiles, and in particular to a polylactic acid and viscose fiber wrapped yarn, and a preparation method and application thereof. Background Art

[0002] With the rapid development of economy and science and technology, people's living standards are constantly improving and their awareness of environmental protection and low carbon is increasing. Now the industry pays more and more attention to the functionality of textiles, and consumers have higher and higher requirements for the comfort and safety of clothing. Therefore, many new varieties and new textile materials have been launched in this field. How to improve the functional properties of textile materials such as beauty, comfort, and degradability in today's pursuit of environmental protection and low carbon has become a focus and hot spot in this field.

[0003] Among textile materials, polylactic acid fiber is made from starch-containing agricultural products such as corn, wheat, and beets. After fermentation to produce lactic acid, it is made by polycondensation and melt spinning. Polylactic acid fiber is a synthetic fiber whose raw materials can be planted and is easy to plant, and whose waste can be naturally degraded in nature. It can be decomposed into carbon dioxide and water by microorganisms in soil or seawater. It does not emit toxic gases when burned and does not cause pollution. It is a sustainable ecological fiber. Polylactic acid fiber fabrics have good hand feel and drape, are UV-resistant, and have low flammability. They are suitable for various fashions, casual wear, sports goods, and sanitary products, etc., and have broad application prospects.

[0004] However, the strength of polylactic acid fiber yarn is relatively low, and the abrasion resistance and anti-pilling performance of blended fabrics are poor, which needs further improvement. Summary of the invention

[0005] In view of this, the present invention provides a polylactic acid and viscose fiber wrapped yarn and a preparation method and application thereof. The polylactic acid fiber blended yarn provided by the present invention has good strength, which is beneficial to improving the wear resistance and anti-pilling properties of the fabric.

[0006] The present invention provides a method for preparing a polylactic acid and viscose fiber wrapped yarn, comprising the following steps: using viscose fiber roving and polylactic acid filaments as raw materials, adopting a long-short wrapped composite spun yarn process to obtain the polylactic acid and viscose fiber wrapped yarn;

[0007] The viscose fiber roving has a basis weight of 2.6-3.0 g / 10 m and a twist coefficient of 65-75; the mass ratio of the viscose fiber roving to the polylactic acid filament is 10-45:55-90.

[0008] In an embodiment of the present invention, the viscose fiber roving is formed by viscose staple fiber raw material through the processes of cleaning, carding, drawing and roving, and the cleaning process includes cotton grabbing, cotton opening, cotton blending and cotton cleaning.

[0009] In the embodiment of the present invention, the beater descending stroke of the cotton grabbing process is 2.3-2.7 mm, and the cotton cleaning process controls the uneven weight rate of the cotton roll to be within 1.2%.

[0010] In an embodiment of the present invention, the cylinder speed of the carding process is 300-360 r / min, and the cotton web neps are controlled within 8 particles / gram.

[0011] In an embodiment of the present invention, the drawing process is a multi-pass process, and the drafting multiple of each pass is between 1.4 and 1.7; the gauge of the roving process is 27×33 mm.

[0012] In an embodiment of the present invention, the polylactic acid filaments are polylactic acid solution-dyed filaments, and enter the composite spun yarn process after a winding process, and the filament tension of the winding process is controlled at 18 to 23 cN.

[0013] In an embodiment of the present invention, in the composite spun yarn process, the viscose fiber roving enters the front zone for drawing through the feeding bell mouth, and the polylactic acid filament is introduced into the composite yarn channel under stable tension adjustment.

[0014] In an embodiment of the present invention, the composite spun yarn process is followed by winding, and the winding speed is 1000-1200 m / min.

[0015] The present invention provides polylactic acid and viscose fiber wrapped yarn obtained by the preparation method as described above.

[0016] The present invention provides a fabric, comprising the polylactic acid and viscose fiber wrapped yarn mentioned above.

[0017] Compared with the prior art, the present invention mainly adopts the long / short composite wrapped yarn process technology, selects polylactic acid filaments and viscose staple rovings as raw materials, the viscose fiber rovings are quantitatively 2.6-3.0g / 10m, and the twist coefficient is 65-75; and the mass ratio of viscose fiber to polylactic acid filaments is 10-45:55-90. The present invention utilizes the wrapping structure of viscose staple fibers and polylactic acid filaments and the cohesion between fibers, etc., which can reduce the slippage of staple fibers, increase the strength of yarns, reduce the hairiness of yarns, improve the weaving efficiency, and further improve the wear resistance and anti-pilling properties of fabrics. Therefore, the present invention achieves the high-strength and wear-resistant effect of polylactic acid blended yarns while ensuring the good wearing comfort and green environmental protection of textile products.

[0018] Furthermore, the present invention preferably uses solution-dyed polylactic acid filaments and viscose fibers to form wrapped yarns, which can also improve the problem of difficult-to-control dyeing of polylactic acid fiber blended yarns. DETAILED DESCRIPTION

[0019] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in combination with the solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] The invention provides a method for preparing a polylactic acid and viscose fiber wrapped yarn, comprising the following steps: using viscose fiber roving and polylactic acid filaments as raw materials, wherein the viscose fiber roving has a basis weight of 2.6-3.0 g / 10 m and a twist coefficient of 65-75; adopting a long-short wrapped composite spun yarn process to obtain the polylactic acid and viscose fiber wrapped yarn; the mass ratio of the viscose fiber roving to the polylactic acid filament is 10-45:55-90.

[0021] The embodiment of the present invention uses viscose staple fiber (referred to as viscose staple fiber) as one of the raw materials; the usual preparation process of viscose fiber includes: alkalizing plant cellulose to form alkali cellulose, reacting with carbon disulfide to form cellulose xanthate, dissolving in dilute alkali solution, and the resulting viscous solution is called viscose, and the viscose is obtained after wet spinning and a series of treatment processes. Viscose fiber has good hygroscopicity and hand quality; under normal atmospheric conditions, its moisture regain is about 13%. The embodiment of the present invention uses ordinary viscose staple fiber commercial products. The short fiber is relatively continuous filament. The length of viscose staple fiber can be 32-38 mm, and the fineness can be 1.0-1.67 dtex.

[0022] In the embodiment of the present invention, the viscose fiber is subjected to a cotton cleaning process. The cotton cleaning can adopt the process principles of short process, less beating and less falling, more loose and fast feeding, and low speed, which is conducive to removing impurities and forming a uniform cotton roll, which can be called a "cotton roll". Specifically, the beater of the A002 cotton plucker has flat ribs, the beater's descending stroke is 2.5±0.2mm, the speed is 750±50r / min, the rotary trolley speed is 2.3±0.3r / min, the speed of the two parallel beaters of the A035 cotton opener is 550×670r / min, the FA106 cotton blender adopts a combing needle beater with a speed of 550±50r / min, and the A076 cotton cleaner adopts a combing needle beater with a speed of 850±50r / min. The distance between the beater and the dust bar is enlarged to 11±1mm, and the uneven weight rate of the cotton roll is controlled within 1.2%. Among them, the above equipment is well known to those skilled in the art.

[0023] In the embodiment of the present invention, the obtained cotton roll is subjected to a combing process (which may be called combing), and the combing may adopt a process of light weight, slow speed, small tension, and appropriately enlarged spacing, which is conducive to forming a uniform cotton mesh, which may be called a "cotton web". Specifically, the licker-in speed of the combing equipment is 780±50r / min, the licker-in needle cloth is 5010*5032, the cylinder speed is 330±30r / min, the cylinder needle cloth is AC2030×01550D, and the flat plate needle cloth is MCH45D; the doffer speed is 20±3r / min, the spacing between the flat plate and the cylinder is 9, 8, 8, 8, 9 inch silk, and the cotton web knots are controlled within 8 grains / gram.

[0024] Afterwards, the embodiment of the present invention performs a drawing process; its drafting distribution and the distance between the front and rear zones affect the yarn dryness. In order to make the fibers in production straight and parallel, as a preferred method, the drawing process performs two passes of merging, the number of combined fibers is 6, the drafting after the first pass of drawing is 1.70 times, and the drafting after the second pass of drawing is 1.46 times.

[0025] In the embodiment of the present invention, the raw sliver formed by drawing is subjected to the roving process, preferably with light weight, large gauge and small tension. Under the premise of ensuring normal drafting in the spun yarn process, the roving weight is 2.8±0.2g / 10m, the roving roller gauge is 11mm×27mm×33mm, and the roving twist coefficient is 70±5. The twist coefficient is a relative value representing the degree of twisting of the yarn in combination with the linear density, which can be used to compare the degree of twisting of yarns of different thicknesses; the twist coefficient can be calculated based on the twist of the yarn and the linear density of the yarn.

[0026] In addition, the embodiment of the present invention carries out a winding process for the polylactic acid filaments dyed with the stock solution, and the winding is the conversion of the coiled wire to the tube wire. The winding speed can be selected to be 600m / min-750m / min, the wire tension is controlled at 18cN-23cN, further 19-22cN, and the humidity is controlled at 50%±2%.

[0027] In the embodiment of the present invention, the obtained viscose fiber roving and polylactic acid filament (PLA filament) are subjected to the spinning process, mainly using the long / short composite yarn process technology, the viscose roving is fed into the bell mouth of the roving device, and enters the front zone for drawing, the drawing multiple of the spun yarn is 40-60 times, the drawing multiple of the rear zone is 1.15-1.22 times, the surface distance of the spun yarn drawing gauge roller is 18mm×40mm, and the front roller speed is 130-150r / min; the converted tube wire of the stock solution-dyed polylactic acid filament is pushed onto the spindle of the spinning machine, and the filament is fed from the front roller through the yarn guide rod, the filament tension stabilizing device and the guide wheel, and the non-drawing component is fed, and the distance between the filament and the short fiber triangle area is 0.5-1mm, thereby forming a wrapped composite yarn structure. Among them, during operation, the flute tube is ensured to be unobstructed to prevent yarn defects and keep the yarn channel smooth. Furthermore, the mass ratio of the viscose fiber roving to the polylactic acid filament is 10-45:55-90, for example, 35:65, to ensure good comprehensive performance of the yarn.

[0028] In a specific embodiment of the present invention, the yarn after the spinning process is subjected to a winding process; the Japanese Murata Ubo winding equipment can be selected, the package tension is reduced to 1.0N, the speed is 1100±100m / min, the channel is kept smooth, and the hairiness is reduced.

[0029] The embodiment of the present invention provides a polylactic acid and viscose fiber wrapped yarn obtained by the preparation method as described above, which has good strength and other characteristics. In some embodiments, it is a mixed color product, which can avoid the problem of difficult control of dyeing in the printing and dyeing process. In some embodiments, the breaking strength of the wrapped yarn can be above 205 cN, for example, 206-215 cN.

[0030] The embodiment of the present invention further provides a fabric, comprising the polylactic acid and viscose fiber wrapped yarn as described above. Based on the characteristics of the blended wrapped yarn, the fabric has good wear resistance and anti-pilling performance, and is environmentally friendly.

[0031] In order to better illustrate the present invention, the following examples are further illustrated. Unless otherwise specified, the various reagents and raw materials used in the present invention are all commercially available products or products obtained by recognized methods. Unless otherwise specified, the proportions involved are all mass proportions. The length of the viscose staple fiber is 32 to 38 mm, and the fineness is 1.0 to 1.67 dtex; the specification of the PLA filament is 75D / 36f.

[0032] Example 1

[0033] The viscose fiber is subjected to a cleaning process, in which the beaters of the A002 cotton plucker have flat ribs, a beater descending stroke of 2.5mm, a speed of 750r / min, a rotary trolley speed of 2.3r / min, the speeds of the two parallel beaters of the A035 cotton opener are 550×670r / min, the FA106 cotton blender uses a combing needle beater with a speed of 550r / min, and the A076 cotton cleaner uses a combing needle beater with a speed of 850r / min. The distance between the beater and the dust bar is enlarged to 11mm, and the uneven weight rate of the cotton rolls is controlled within 1.2%.

[0034] In the carding process, the licker-in speed is 780±50r / min, the licker-in needle clothing is 5010*5032, the cylinder speed is 330r / min, the cylinder needle clothing is AC2030×01550D, and the flat plate needle clothing is MCH45D; the doffer speed is 20r / min, the spacing between the flat plate and the cylinder is 9, 8, 8, 8, 9 inches, and the cotton net knots are controlled within 8 grains / gram.

[0035] In the drawing process, two passes are used, the number of combined roots is 6, the drafting after the first pass is 1.70 times, and the drafting after the second pass is 1.46 times; in the roving process, the roving quantity is 2.8g / 10m, and the roving roller spacing is 11mm×27mm×33mm to obtain viscose fiber roving.

[0036] The polylactic acid filaments colored by the stock solution are subjected to a winding process, wherein the winding speed is selected to be 600m / min-750m / min, the filament tension is controlled at 18cN-23cN, and the humidity is controlled at 50%±2%.

[0037] The spinning adopts the long / short composite yarn process technology. The viscose roving is fed into the bell mouth of the roving device and enters the front zone for drawing. The roving drawing multiple is 50-60 times, and the back zone drawing is 1.15-1.22 times. The surface distance of the roving drawing gauge roller is 18mm×40mm, the gauge block is 2.3mm, the cradle pressure is 180CN±5, the steel collar is PG1-4254, the wire ring is 7 / 0, and the front roller speed is 140-150r / min; the converted bobbin of the liquid-dyed polylactic acid filament is pushed onto the spinning frame spindle, and the filament is fed from the front roller through the yarn guide rod, the filament tension stabilizing device and the guide wheel without going through the drawing component. The distance between the filament and the short fiber triangle area is 0.5-1mm. During operation, the flute tube is ensured to be unobstructed and the yarn channel is kept smooth.

[0038] The winding machine used was Japan's Murata U-Bo winding machine, the bobbin tension was reduced to 1.0N, the machine speed was 1100m / min, and the polylactic acid and viscose fiber wrapped yarn was obtained.

[0039] Example 2

[0040] The viscose fiber was subjected to a cotton cleaning process, in which the beaters of the A002 cotton plucker had flat ribs, a beater descending stroke of 2.7mm, a speed of 800r / min, a rotary trolley speed of 2.6r / min, the speeds of the two parallel beaters of the A035 cotton opener were 550×670r / min, the FA106 cotton blender adopted a combing needle beater with a speed of 550±50r / min, and the A076 cotton cleaner adopted a combing needle beater with a speed of 890r / min. The distance between the beater and the dust bar was enlarged to 12mm, and the uneven weight rate of the cotton rolls was controlled within 1.2%.

[0041] In the carding process, the licker-in speed is 780r / min, the licker-in needle clothing is 5010*5032, the cylinder speed is 330r / min, the cylinder needle clothing is AC2030×01550D, and the flat plate needle clothing is MCH45D; the doffer speed is 23r / min, the spacing between the flat plate and the cylinder is 9, 8, 8, 8, 9 inches, and the cotton net knots are controlled within 8 grains / gram.

[0042] In the drawing process, two passes are used, the number of combined roots is 6, the drafting after the first pass is 1.70 times, and the drafting after the second pass is 1.46 times; the roving quantity is 2.9g / 10m, the roving roller spacing is 11mm×27mm×33mm, and the roving twist coefficient is 75 to obtain viscose fiber roving.

[0043] The polylactic acid filaments colored by the stock solution are subjected to a winding process, wherein the winding speed is selected to be 600m / min-750m / min, the filament tension is controlled at 18cN-23cN, and the humidity is controlled at 50%±2%.

[0044] The spinning adopts long / short composite yarn process technology. The viscose roving is fed into the bell-mouth of the roving device and enters the front zone for stretching. The roving stretching multiple is 40-50 times, and the rear zone stretching is 1.15-1.22 times. The surface distance of the roving stretching roller is 18mm×40mm, and the front roller speed is 140-150r / min. The converted bobbin of the solution-dyed polylactic acid filament is pushed onto the spinning frame spindle. The filament passes through the yarn guide rod, the filament tension stabilizing device and the guide wheel, and is fed from the front roller without going through the drafting component. The distance between the filament and the short fiber triangle area is 0.5-1mm. During operation, the flute tube is ensured to be unobstructed and the yarn channel is kept smooth.

[0045] The winding machine used was Japan's Murata U-Bo winding machine, the bobbin tension was reduced to 1.0N, the machine speed was 1200m / min, and the polylactic acid and viscose fiber wrapped yarn was obtained.

[0046] Example 3

[0047] The viscose fiber is subjected to a cotton cleaning process, in which the beaters of the A002 cotton plucker have flat ribs, a beater descending stroke of 2.5mm, a speed of 750r / min, a rotary trolley speed of 2.3r / min, the speeds of the two parallel beaters of the A035 cotton opener are 550×670r / min, the FA106 cotton blender uses a combing needle beater with a speed of 550r / min, and the A076 cotton cleaner uses a combing needle beater with a speed of 850±50r / min. The distance between the beater and the dust bar is enlarged to 11mm, and the uneven weight rate of the cotton rolls is controlled within 1.2%.

[0048] In the carding process, the licker-in speed is 780r / min, the licker-in needle clothing is 5010*5032, the cylinder speed is 330r / min, the cylinder needle clothing is AC2030×01550D, and the flat plate needle clothing is MCH45D; the doffer speed is 20r / min, the spacing between the flat plate and the cylinder is 9, 8, 8, 8, 9 inches, and the cotton net knots are controlled within 8 grains / gram.

[0049] In the drawing process, two passes are used, the number of combined roots is 6, the drafting after the first pass is 1.70 times, and the drafting after the second pass is 1.46 times; the roving quantity is 2.8g / 10m, and the roving roller spacing is 11mm×27mm×33mm to obtain viscose fiber roving.

[0050] The polylactic acid filaments colored by the stock solution are subjected to the winding process, the winding speed is selected to be 600m / min-750m / min, the filament tension is controlled at 18cN-23cN, and the humidity is controlled at 50%±2%.

[0051] The spinning adopts long / short composite yarn process technology. The viscose roving is fed into the bell-mouth of the roving device and enters the front zone for stretching. The roving stretching multiple is 40-50 times, and the rear zone stretching is 1.15-1.22 times. The surface distance of the roving stretching roller is 18mm×40mm, and the front roller speed is 140-150r / min. The converted tube of liquid-dyed polylactic acid filament is pushed onto the spinning frame spindle. The filament is fed from the front roller through the yarn guide rod, filament tension stabilizing device and guide wheel without going through the drafting component. The distance between the filament and the short fiber triangle area is 0.5-1mm. During operation, the flute tube must be unobstructed and the yarn channel must be smooth.

[0052] The winding machine used was Japan's Murata U-Bo winding machine, the bobbin tension was reduced to 1.0N, the machine speed was 1100m / min, and the polylactic acid and viscose fiber wrapped yarn was obtained.

[0053] Comparative Example 1

[0054] The viscose staple fiber and polylactic acid staple fiber are premixed and then subjected to the cleaning process. The A002 cotton plucking machine has flat ribs on the beaters, a beater descending stroke of 2.5mm, a speed of 750r / min, a rotary trolley speed of 2.3m / min, and two parallel beaters of the A035 cotton opener at speeds of 550×670r / min. The FA106 cotton blending machine uses a combing needle beater at a speed of 550r / min, and the A076 cotton cleaning machine uses a combing needle beater at a speed of 850±50r / min. The distance between the beater and the dust bar is enlarged to 11mm, and the uneven weight rate of the cotton rolls is controlled within 1.2%.

[0055] In the carding process, the licker-in speed is 780r / min, the licker-in needle clothing is 5010*5032, the cylinder speed is 330r / min, the cylinder needle clothing is AC2030×01550D, and the flat plate needle clothing is MCH45D; the doffer speed is 20r / min, and the gauge between the flat plate and the cylinder is 9, 8, 8, 8, and 9 inches.

[0056] In the drawing process, two passes are used, the number of combined roots is 6, the drafting after the first pass is 1.70 times, and the drafting after the second pass is 1.46 times; the roving quantity is 3.2g / 10m, and the roving gauge roller is 11mm×27mm×33mm to obtain a viscose fiber / polylactic acid staple fiber mixed roving.

[0057] The siro compact spinning process is adopted for the siro spinning. Two viscose fiber / PLA staple fiber mixed rovings are passed through the bell mouth of the roving feeding device in parallel with a certain distance, and enter the spun yarn drafting area for drafting. The drafted slivers are output through the front roller jaws. Under the action of the negative pressure gathering device of the equipment, the fibers of the two slivers are straighter and more tightly embraced. Finally, they are gripped and output by the small roller to complete the twisting, and the viscose fiber / PLA staple fiber mixed colored spun yarn is obtained.

[0058] The winding machine used was Japanese Murata U-Polo, the package tension was reduced to 1.0N, and the speed was 1100m / min to obtain the viscose rayon fiber / polylactic acid staple fiber mixed color spun yarn.

[0059] The yarn samples prepared in the above examples were tested for performance using a national standard method in this field, and the results are as follows.

[0060] Table 1 Comparative test results of polylactic acid 65 / viscose 35_40 Ne color spinning index

[0061]

[0062] It can be seen from the above embodiments that the embodiments of the present invention use the long / short composite wrapped yarn process technology, select polylactic acid filaments and viscose staple fiber rovings as raw materials, the viscose fiber rovings are quantitatively 2.6-3.0g / 10m, and the twist coefficient is 65-75; and the mass ratio of viscose fiber to polylactic acid filament is 10-45:55-90. The present invention utilizes the wrapping structure of viscose staple fiber and polylactic acid filament and the cohesion between fibers to improve the weaving efficiency, thereby improving the wear resistance and anti-pilling properties of the fabric. The present invention achieves the high-strength and wear-resistant effect of polylactic acid blended yarn while ensuring the good wearing comfort and green environmental protection of textile products. In addition, the present invention preferably uses liquid-dyed polylactic acid filaments and viscose fibers to form wrapped yarns, which can also improve the problem of difficult control of dyeing of polylactic acid fiber blended yarns.

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent substitution or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing polylactic acid and viscose fiber wrapped yarn, characterized in that: The following steps are involved: Viscose fiber roving and polylactic acid filaments are used as raw materials and a composite spun yarn process of long and short wrapping is adopted to obtain polylactic acid and viscose fiber wrapped yarn; the viscose fiber roving has a quantitative value of 2.6-3.0g / 10m and a twist coefficient of 65-75; the mass ratio of the viscose fiber roving to the polylactic acid filament is 10-45:55-90.

2. The preparation method according to claim 1, characterized in that: The viscose fiber roving is formed by viscose staple fiber raw materials through the processes of cleaning, carding, drawing and roving, wherein the cleaning process includes cotton grabbing, cotton opening, cotton blending and cotton cleaning.

3. The preparation method according to claim 2, characterized in that: The beater descending stroke of the cotton grabbing process is 2.3-2.7 mm, and the cotton cleaning process controls the uneven weight rate of the cotton roll to be within 1.2%.

4. The preparation method according to claim 3, characterized in that: The cylinder speed of the carding process is 300-360 r / min, and the cotton web neps are controlled within 8 particles / gram.

5. The preparation method according to claim 4, characterized in that: The drawing process is a multi-pass process, and the drafting multiple of each pass is between 1.4 and 1.7; the gauge of the roving process is 27×33 mm.

6. The preparation method according to any one of claims 1 to 5, characterized in that: The polylactic acid filaments are polylactic acid solution-dyed filaments, and enter the composite spun yarn process through a winding process, wherein the filament tension of the winding process is controlled at 18 to 23 cN.

7. The preparation method according to claim 6, characterized in that: In the composite spun yarn process, the viscose fiber roving enters the front zone through the feeding bell mouth for drawing, and the polylactic acid filament is introduced into the composite yarn channel under the stable tension adjustment.

8. The preparation method according to claim 7, characterized in that: The composite spun yarn process is followed by winding, and the winding speed is 1000-1200 m / min.

9. The polylactic acid and viscose fiber wrapped yarn obtained by the preparation method according to any one of claims 1 to 8.

10. A fabric, characterized in that: The invention comprises the polylactic acid and viscose fiber wrapped yarn as described in claim 9.

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