Polylactic acid woven fabric dyeing process

Abstract

The invention discloses a polylactic acid woven fabric dyeing process. The polylactic acid woven fabric dyeing process comprises the following steps of pretreatment, pretreatment, dyeing, post-treatment and sizing. Carrying out plasma treatment on the pretreated polylactic acid woven fabric; the dye liquor comprises a disperse dye dispersing agent, alkylphenol polyoxyethylene ether phosphate and a penetrant; the pH (Potential of Hydrogen) value is 4.5 to 5.5; adding ammonium dihydrogen phosphate after heating, and then heating to 100-105 DEG C; the post-treatment comprises reduction cleaning, bio-enzyme fixation and softening treatment; shaping is carried out under the condition of 65-70%. According to the polylactic acid woven fabric dyeing process, the polylactic acid woven fabric is subjected to plasma pretreatment, and then the weakly acidic dye liquor is used, so that the dyeing effect of the disperse dye can be improved. And through reduction cleaning, color fixing and softening treatment, the color fastness and softness of the fabric can be improved.

Description

Technical Field

[0001] The present invention relates to a dyeing process for a polylactic acid woven fabric, belonging to the dyeing process for polylactic acid fabrics. Background Art

[0002] Polylactic acid (PLA) fiber is a synthetic fiber made from corn, wheat, etc. through fermentation to prepare lactic acid, and then through polymerization and spinning. PLA fiber can be decomposed into CO2 and H2O in nature and has no toxic gases when burned. PLA fiber is a material with good biocompatibility and biodegradability, and can be used as a medical material. In addition, PLA fiber also has excellent drape, hygroscopicity, air permeability, smoothness, as well as heat resistance and ultraviolet resistance, and has good luster and elasticity. Since PLA fiber contains hydrophobic functional groups, it can be dyed with hydrophobic disperse dyes.

[0003] However, polylactic acid fiber is very sensitive to temperature and alkali. For example, if the dyeing temperature exceeds 110 °C, the hand feeling of polylactic acid fiber will become significantly hard and the strength will decrease severely; adding strong alkali during the dyeing process will cause the degradation of polylactic acid. How to design a dyeing process for polylactic acid woven fabric that can reduce the damage to polylactic acid fiber and improve the dyeing fastness has become a problem to be solved. Summary of the Invention

[0004] The purpose of the present invention is to provide a dyeing process for polylactic acid woven fabric, which can reduce the damage to polylactic acid filaments during the dyeing process and improve the dyeing fastness.

[0005] To solve the above technical problems, the purpose of the present invention is achieved as follows:

[0006] A dyeing process for polylactic acid woven fabric according to the present invention includes the following steps:

[0007] S1. Pretreatment: Scouring and desizing the polylactic acid woven fabric, and then drying it;

[0008] S2. Pre-treatment: Performing plasma treatment on both surfaces of the polylactic acid woven fabric after pre-treatment;

[0009] S3. Dyeing: Immersing the pre-treated polylactic acid woven fabric in the dye liquor according to a bath ratio of 1:10 - 15. The dye liquor includes 1 - 5% o.w.f of disperse dye, 1 - 1.5% by mass of dispersant, 0.5 - 1% by mass of alkylphenol polyoxyethylene ether phosphate, and 2 - 3% by mass of penetrant; and using a pH value buffer system to maintain the pH value of the dye liquor at 4.5 - 5.5;

[0010] After heating from room temperature to 85 °C, adding 1 - 1.5% by mass of ammonium dihydrogen phosphate, stirring evenly, and then heating to 100 - 105 °C and maintaining for 30 - 34 min;

[0011] S4. Post-treatment: successively perform reduction cleaning, bio-enzyme color fixation, and softening treatment on the dyed polylactic acid woven fabric;

[0012] The reduction cleaning is to immerse the dyed polylactic acid woven fabric in a reduction cleaning solution containing 1 - 2 g / L of sodium hydrosulfite at a temperature of 50 - 60 °C for 10 - 15 min;

[0013] The bio-enzyme color fixation is to wash the polylactic acid woven fabric after reduction cleaning with clear water and then immerse it in a color fixation solution at 45 - 55 °C for 15 - 25 min; the color fixation solution includes 0.5 - 0.8% o.w.f of laccase;

[0014] The softening treatment is to wash the polylactic acid woven fabric after color fixation with clear water and then immerse it in a softening finishing solution at 26 - 35 °C for 10 - 15 min; the softening finishing solution contains 2 - 4% of natural sophora japonica extract;

[0015] S5. Setting: Set the polylactic acid woven fabric after post-treatment under the condition of 65 - 70%.

[0016] Based on the above solution and as the preferred solution of the above solution: The disperse dye is disperse dye UN-SE red, disperse dye AC-E blue, or disperse dye AC-E yellow.

[0017] Based on the above solution and as the preferred solution of the above solution: The penetrant is penetrant AIBAFIJOW UNI, and the dispersant is dispersant UNIVADINF DFM.

[0018] Based on the above solution and as the preferred solution of the above solution: The preparation process of the polylactic acid woven fabric includes the following processes: warping process, warp pretreatment process, sizing process, slashing process, drying process, drawing-in and reed-in process, weaving process;

[0019] The warping process: warp the polylactic acid filaments with a soft warping device to form a soft warping beam, and control the tension of the polylactic acid filaments at 45 - 50 cN during warping; keep the relative humidity of the environment at 65 - 70% during warping;

[0020] The warp pretreatment process: place the warping beam in an environment of 40 - 50 °C and relative humidity of 65 - 70% for pre-equilibration for 4 - 6 hours, and adjust the moisture content to reach 0.5 - 0.6%;

[0021] The sizing process: Take 10 - 20 parts by mass of starch-modified polylactic acid, 20 - 30 parts by mass of acetate starch, 3 - 5 parts by mass of ethylene glycol, 1 - 2 parts by mass of emulsifier, and 1 - 2 parts by mass of ammonium dihydrogen phosphate, add them into a sizing vat, and add water into the sizing vat. Stir while heating, and heat to 100°C at a heating rate of 1 - 1.5°C / min. Then add 3 - 5 parts by mass of paraffin, 0.2 - 0.4 parts by mass of antistatic agent, and 5 - 8 parts by mass of dopamine-modified polylactic acid copolymer, continue to stir. After complete gelatinization, stop stirring; adjust the pH value to 7 - 7.5, then stir and cool down to 55 - 60°C. The viscosity of the prepared sizing agent is 4.5 - 5.5 Pa·s, thus obtaining the sizing agent;

[0022] The warping process: Use a double-sizing vat warping machine to double-dip and double-roll the warp yarns. Inject the sizing agent prepared in the sizing process into the sizing vat. The temperature of the sizing vat is 55 - 60°C, the vehicle speed is 35 - 40 m / min, the pressing pressure is 15 - 20 KN, the moisture regain is 3 - 5%, and the sizing rate is 12 - 15%;

[0023] The drying process: Conduct wet splitting on the warp yarns after sizing, and dry the warp yarns at 55 - 60°C;

[0024] The process of threading the heddles and reed is to thread, contract, and insert the reed for the warp yarns according to the machine setting process parameters, using OF soft heddle wires;

[0025] In the weaving process, the tension borne by each warp yarn is 0.35 - 0.45 g / d, and an antistatic agent is sprayed at the cloth fell every 30 - 45 min.

[0026] On the basis of the above solution and as a preferred solution of the above solution: The winding density of the soft warp beam is 0.2 - 0.4 g / cm 3 。

[0027] On the basis of the above solution and as a preferred solution of the above solution: The antistatic agent is a cationic quaternary ammonium salt type antistatic agent.

[0028] On the basis of the above solution and as a preferred solution of the above solution: The cationic quaternary ammonium salt type antistatic agent is N,N-bis(α-hydroxyethyl)-N-(3’-dodecyloxy-2’-hydroxypropyl)methylammonium methyl sulfate.

[0029] Based on the above solution and as an optimized solution of the above solution: The preparation process of the starch-modified polylactic acid is as follows: Prepare a slurry of amylose with a concentration of 10-30%, then adjust the pH value to 7-7.5, then add trimethylsilane, stir evenly, then add polylactic acid nanoparticles and stannous octoate, and heat to 55-60 °C, stir and react for 3-4 h, dry, dissolve with CH3Cl, and add methanol for precipitation. Wash the precipitate with methanol and then dry it under vacuum to obtain the starch-modified polylactic acid.

[0030] The beneficial effects of the present invention are as follows: For a dyeing process of a polylactic acid woven fabric involved in the present invention, through the plasma pretreatment of the polylactic acid woven fabric and then using a weakly acidic dyeing solution, the dyeing effect of disperse dyes can be improved. And through reduction cleaning, color fixation and softening treatment, the color fastness and softness of the fabric can be increased. Detailed implementation mode

[0031] The present invention will be further described below in conjunction with specific embodiments.

[0032] Embodiment 1

[0033] A dyeing process of a polylactic acid woven fabric involved in this embodiment includes the following steps:

[0034] S1. Pretreatment: Carry out scouring and desizing treatment on the polylactic acid woven fabric and dry it. Use a pretreatment solution containing alkaline pectinase to carry out desizing treatment on the polylactic acid woven fabric. The pH value of the pretreatment solution is 9, the temperature is 50 °C, the treatment time is 40 min, and the dosage of alkaline pectinase is 2% by mass fraction.

[0035] S2. Pretreatment: Carry out plasma treatment on both sides of the polylactic acid woven fabric after pretreatment; use an XKD-G1 type plasma processor (Shenzhen XinkeDa Automation Equipment Co., Ltd.) for surface treatment. The power is 40 W and the treatment time is 120 s.

[0036] S3. Dyeing: Immerse the pretreated polylactic acid woven fabric in the dyeing solution according to a bath ratio of 1:10. The dyeing solution includes 5% o.w.f. of disperse dye, 1% by mass fraction of dispersant, 1% by mass fraction of alkylphenol polyoxyethylene ether phosphate, and 2% by mass fraction of penetrant; and use a pH value buffer system to maintain the pH value of the dyeing solution at 5.5. After heating from room temperature to 85 °C, add 1% by mass fraction of ammonium dihydrogen phosphate, stir evenly and then heat up to 105 °C and keep it for 30 min.

[0037] Further, the disperse dye is disperse dye UN-SE red, disperse dye AC-E blue or disperse dye AC-E yellow. The penetrant is penetrant AI BAFIJOW UNI, and the dispersant is dispersant UNIVADINF DFM.

[0038] S4. Post-treatment: The dyed polylactic acid woven fabric is subjected to reduction cleaning, enzymatic fixation and softening treatment in sequence.

[0039] The reduction cleaning is to immerse the dyed polylactic acid woven fabric in a reduction cleaning solution containing 2 g / L of sodium dithionite at a temperature of 50 °C for 15 min.

[0040] The enzymatic fixation is to wash the polylactic acid woven fabric after reduction cleaning with clear water and then immerse it in a fixation solution at 45 °C for 25 min; the fixation solution contains 0.5% o.w.f of laccase.

[0041] The softening treatment is to wash the polylactic acid woven fabric after fixation with clear water and then immerse it in a softening finishing solution at 35 °C for 10 min; the softening finishing solution contains 4% of natural Chinese honey locust extract.

[0042] S5. Setting: The polylactic acid woven fabric after post-treatment is set under the condition of 65%.

[0043] Further, the weaving process of the polylactic acid woven fabric includes a warping process, a warp yarn pretreatment process, a sizing process, a slashing process, a drying process, a harnessing and denting process, and a weaving process.

[0044] The warping process: The polylactic acid filament is warped by a slack warping device to form a slack warp beam. During warping, the tension of the polylactic acid filament is controlled at 50 cN; the relative humidity of the environment is maintained at 65% during warping. The winding density of the prepared slack warp beam is 0.4 g / cm 3 . The specification of the polylactic acid filament is 75D / 36F.

[0045] The warp yarn pretreatment process: Place the warp beam in an environment at 40 °C and a relative humidity of 70% for pre-equilibration for 4 hours, and adjust the moisture content to reach 0.6%.

[0046] The sizing process: Take 10 parts by mass of starch-modified polylactic acid, 30 parts by mass of acetate starch, 3 parts by mass of ethylene glycol, 2 parts by mass of emulsifier, and 1 part by mass of ammonium dihydrogen phosphate, add them into a sizing vat, and add water into the sizing vat. Heat and stir simultaneously, and heat to 100 °C at a heating rate of 1.5 °C / min. Then add 3 parts by mass of paraffin, 0.4 part by mass of antistatic agent, and 5 parts by mass of dopamine-modified polylactic acid copolymer, continue to stir. After complete gelatinization, stop stirring; adjust the pH value to 7.5, then stir and cool down to 55 °C. The viscosity of the prepared sizing is 5.5 Pa·s, thus obtaining the sizing.

[0047] Further, the antistatic agent is a cationic quaternary ammonium salt type antistatic agent. The cationic quaternary ammonium salt type antistatic agent is N,N-bis(α-hydroxyethyl)-N-(3’-dodecyloxy-2’-hydroxypropyl) methylammonium methyl sulfate.

[0048] Further, the preparation process of the starch-modified polylactic acid is as follows: Prepare a 10% concentration slurry of amylose, then adjust the pH value to 7, add trimethylsilane, stir evenly, then add polylactic acid nanoparticles and stannous octoate, and heat to 60 °C, stir and react for 3 h. After drying, dissolve it with CH3Cl, and add methanol for precipitation. Wash the precipitate with methanol and then dry it under vacuum to obtain the starch-modified polylactic acid.

[0049] The warping process: Use a double-sizing vat warping machine to double-dip and double-roll the warp yarns. Inject the sizing prepared in the sizing process into the sizing vat. The temperature of the sizing vat is 60 °C, the vehicle speed is 35 m / min, the pressing pressure is 20 KN, the moisture regain is 3%, and the sizing rate is 15%.

[0050] The drying process: Perform wet splitting on the sized warp yarns, and dry the warp yarns at 55 °C.

[0051] The process of threading and reed insertion is to thread, draw in, and insert the reed for the warp yarns according to the loom setup process parameters, using OF soft heddles.

[0052] In the weaving process, the tension borne by each warp yarn is 0.45 g / denier, and an aqueous solution of antistatic agent SN with a mass fraction of 10% is sprayed at the cloth fell every 30 min. The weft yarn used is polylactic acid filament with a fineness of 75 D / 36 F. Specifically, plain weave is used for interlacing, and weaving is carried out on a Tsudakoma ZAX9100 air-jet loom. The vehicle speed is 700 r / min, and the warp and weft densities are 130 per / 10 cm and 70 per / 10 cm respectively.

[0053] During the weaving process, the number of warp stops per hour is 0.5, and the number of weft stops per hour is 1.8.

[0054] Example 2

[0055] A dyeing process for a polylactic acid woven fabric involved in this embodiment includes the following steps:

[0056] S1. Pretreatment: The polylactic acid woven fabric is scoured and desized and then dried. A pretreatment solution containing alkaline pectinase is used to desize the polylactic acid woven fabric. The pH value of the pretreatment solution is 8, the temperature is 60 °C, the treatment time is 30 min, and the dosage of alkaline pectinase is 3% by mass fraction.

[0057] S2. Preconditioning: Plasma treatment is carried out on both surfaces of the polylactic acid woven fabric after pretreatment; an XKD-G1 type plasma processor (Shenzhen XinkeDa Automation Equipment Co., Ltd.) is used for surface treatment. The power is 40 W and the treatment time is 80 s.

[0058] S3. Dyeing: The pretreated polylactic acid woven fabric is immersed in the dye liquor at a liquor ratio of 1:15. The dye liquor includes 1% o.w.f of disperse dye, 1.5% by mass fraction of dispersant, 0.5% by mass fraction of alkylphenol polyoxyethylene ether phosphate, and 3% by mass fraction of penetrant; and a pH value buffer system is used to maintain the pH value of the dye liquor at 4.5. After heating from room temperature to 85 °C, 1.5% by mass fraction of ammonium dihydrogen phosphate is added, and after stirring evenly, it is further heated to 100 °C and kept for 34 min.

[0059] Furthermore, the disperse dye is disperse dye UN-SE red, disperse dye AC-E blue or disperse dye AC-E yellow. The penetrant is penetrant AI BAFIJOW UNI, and the dispersant is dispersant UNIVADINF DFM.

[0060] S4. Post-treatment: The dyed polylactic acid woven fabric is subjected to reduction cleaning, bio-enzyme fixation and softening treatment in sequence.

[0061] The reduction cleaning is to immerse the dyed polylactic acid woven fabric in a reduction cleaning solution containing 2 g / L of sodium dithionite at a temperature of 50 °C for 15 min.

[0062] The bio-enzyme fixation is to immerse the polylactic acid woven fabric after reduction cleaning in a fixing solution at 45 °C for 25 min after washing with clear water; the fixing solution includes 0.5% o.w.f of laccase.

[0063] The softening treatment is to immerse the polylactic acid woven fabric after fixation in a softening finishing solution at 35 °C for 10 min after washing with clear water; the softening finishing solution contains 4% of natural sophora japonica extract.

[0064] S5. Stentering: The polylactic acid woven fabric after post-treatment is stented under the condition of 65%.

[0065] Furthermore, the weaving process of polylactic acid woven fabric includes warping process, warp yarn pretreatment process, sizing process, slashing process, drying process, heddle threading and reed insertion process, and weaving process.

[0066] The warping process: The loose warp beam formed by warping polylactic acid filaments with a loose warping device, the tension of polylactic acid filaments during warping is controlled at 45 cN; the relative humidity of the environment is maintained at 70% during warping. The winding density of the prepared loose warp beam is 0.2 g / cm 3 . The specification of the polylactic acid filament is 75D / 48F.

[0067] The warp yarn pretreatment process: Place the warp beam in an environment of 50°C and 65% relative humidity for pre-equilibration for 6 hours, and adjust the moisture content to reach 0.5%.

[0068] The sizing process: Take 20 parts by mass of starch-modified polylactic acid, 20 parts by mass of acetate starch, 5 parts by mass of ethylene glycol, 1 part by mass of emulsifier, 2 parts by mass of ammonium dihydrogen phosphate, add them into the sizing barrel, and add water into the sizing barrel, heat and stir at the same time, and heat to 100°C at a heating rate of 1°C / min, then add 5 parts by mass of paraffin, 0.2 parts by mass of antistatic agent and 8 parts by mass of dopamine-modified polylactic acid copolymer, continue to stir, stop stirring after complete gelatinization; adjust the pH value to 7, then stir and cool to 60°C, the viscosity of the prepared sizing is 4.5 Pa·s, and the sizing is obtained.

[0069] Furthermore, the antistatic agent is a cationic quaternary ammonium salt type antistatic agent. The cationic quaternary ammonium salt type antistatic agent is N,N-bis(α-hydroxyethyl)-N-(3'-dodecyloxy-2'-hydroxypropyl)methylammonium methyl sulfate.

[0070] Furthermore, the preparation process of the starch-modified polylactic acid is as follows: Prepare a 30% concentration slurry of amylose, then adjust the pH value to 7.5, add trimethylsilane, stir evenly, then add polylactic acid nanoparticles and stannous octoate, and heat to 55°C, stir and react for 4 h, dry, dissolve with CH3Cl, add methanol for precipitation, wash the precipitate with methanol and then vacuum dry to obtain starch-modified polylactic acid.

[0071] The slashing process: Use a double-slurry-tank slasher to double-dip and double-roll the warp yarns, inject the sizing prepared in the sizing process into the slurry tank, the temperature of the slurry tank is 55°C, the vehicle speed is 40 m / min, the pressing pressure is 15 KN, the moisture regain is 5%, and the sizing rate is 12%.

[0072] The drying process: Carry out wet splitting on the sized warp yarns, and dry the warp yarns at 60°C;

[0073] The heddle threading and reed insertion process is to thread, draw in the warp threads according to the processing parameters of the loom, and use OF soft heddle wires;

[0074] In the weaving process, the tension borne by each warp thread is 0.35 g / denier, and an aqueous solution of antistatic agent SN with a mass fraction of 10% is sprayed at the cloth fell every 45 minutes. The specification of the polylactide filament used for the weft yarn is 75D / 48F. The fabric is woven with a 1-up 2-down twill weave on a Tsudakoma ZAX9100 air-jet loom at a weaving speed of 700 r / min, with warp and weft densities of 130 threads per 10 cm and 70 threads per 10 cm respectively.

[0075] During the weaving process, the warp stop rate per loom-hour is 0.7, and the weft stop rate per loom-hour is 2.1.

[0076] The color fastness of the polylactic acid woven fabrics prepared in Example 1 and Example 2 was tested. The color fastness to soaping was 4-5 grades and 4-5 grades respectively; in the color fastness to rubbing test, the dry rubbing color fastness was 4-5 grades and 4-5 grades respectively, and the wet rubbing color fastness was 4-5 grades and 4-5 grades respectively; in the color fastness to sublimation, the color change fastness was 4-5 grades and 4-5 grades respectively, and the staining fastness was 4 grades and 4 grades respectively.

[0077] The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and variations based on the concept of the present invention without creative efforts. Therefore, all technical solutions that can be obtained by those skilled in the art in the technical field of the present invention through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should fall within the protection scope determined by the claims.

Claims

1. A dyeing process for polylactic acid woven fabrics, characterized in that, It includes the following steps: S1. Pretreatment: Scouring and desizing the polylactic acid woven fabric, and then drying it; S2. Preconditioning: Performing plasma treatment on both surfaces of the polylactic acid woven fabric after pretreatment; S3. Dyeing: Immersing the pretreated polylactic acid woven fabric into the dye liquor at a bath ratio of 1:10 - 15. The dye liquor includes 1 - 5% o.w.f. of disperse dyes, 1 - 1.5% by mass of a dispersant, 0.5 - 1% by mass of alkylphenol polyoxyethylene ether phosphate, and 2 - 3% by mass of a penetrant; and using a pH buffer system to maintain the pH value of the dye liquor at 4.5 - 5.5; After heating from room temperature to 85°C, add 1 - 1.5% by mass of ammonium dihydrogen phosphate, stir evenly, and then heat up to 100 - 105°C and hold for 30 - 34 min; S4. Post-treatment: Sequentially performing reduction cleaning, bio-enzyme fixation, and softening treatment on the dyed polylactic acid woven fabric; The reduction cleaning is to immerse the dyed polylactic acid woven fabric into a reduction cleaning solution containing 1 - 2 g / L of sodium dithionite at a temperature of 50 - 60°C for 10 - 15 min; The bio-enzyme fixation is to immerse the polylactic acid woven fabric after reduction cleaning into a fixation solution at 45 - 55°C for 15 - 25 min after washing with clear water; the fixation solution includes 0.5 - 0.8% o.w.f. of laccase; The softening treatment is to immerse the polylactic acid woven fabric after fixation into a softening finishing solution at 26 - 35°C for 10 - 15 min after washing with clear water; the softening finishing solution contains 2 - 4% of natural sophora japonica extract; S5. Setting: Setting the polylactic acid woven fabric after post-treatment under the condition of 65 - 70%.

2. The dyeing process of a polylactic acid woven fabric according to claim 1, characterized in that, The disperse dyes are disperse dye UN-SE red, disperse dye AC-E blue, or disperse dye AC-E yellow.

3. A polylactic acid woven fabric dyeing process according to claim 1, characterized in that, The penetrant is penetrant AI BAFIJOW UNI, and the dispersant is dispersant UNIVADINF DFM.

4. A dyeing process for a polylactic acid woven fabric according to claim 1, characterized in that, The preparation process of the polylactic acid woven fabric includes the following processes: warping process, warp yarn pretreatment process, sizing process, slashing process, drying process, denting and reed threading process, weaving process; The warping process: Using a soft warping device to warp the polylactic acid filaments to form a soft warping beam. During warping, the tension of the polylactic acid filaments is controlled at 45 - 50 cN; the relative humidity of the environment is maintained at 65 - 70% during warping; The warp yarn pretreatment process: Placing the warping beam in an environment at 40 - 50°C and a relative humidity of 65 - 70% for pre-equilibration for 4 - 6 hours, and adjusting the moisture content to reach 0.5 - 0.6%; The sizing process: Take 10 - 20 parts by mass of starch-modified polylactic acid, 20 - 30 parts by mass of acetate starch, 3 - 5 parts by mass of ethylene glycol, 1 - 2 parts by mass of emulsifier, 1 - 2 parts by mass of ammonium dihydrogen phosphate, add them into a sizing vat, and add water into the sizing vat. Stir while heating, and heat to 100°C at a heating rate of 1 - 1.5°C / min. Then add 3 - 5 parts by mass of paraffin, 0.2 - 0.4 parts by mass of antistatic agent, and 5 - 8 parts by mass of dopamine-modified polylactic acid copolymer, continue to stir. After complete gelatinization, stop stirring; adjust the pH value to 7 - 7.5, then stir and cool down to 55 - 60°C. The viscosity of the prepared sizing agent is 4.5 - 5.5 Pa·s, thus obtaining the sizing agent; The warping process: Use a double-sizing vat warping machine to double-dip and double-roll the warp yarn. Inject the sizing agent prepared in the sizing process into the sizing vat. The temperature of the sizing vat is 55 - 60°C, the vehicle speed is 35 - 40 m / min, the squeezing pressure is 15 - 20 KN, the moisture regain is 3 - 5%, and the sizing rate is 12 - 15%; The drying process: Carry out wet splitting of the warped warp yarn, and dry the warp yarn at 55 - 60°C; The heddling and reed threading process is to thread and reed the warp yarn according to the loom processing parameters, using OF soft heddles; In the weaving process, the tension borne by each warp yarn is 0.35 - 0.45 g / denier, and an antistatic agent is sprayed at the cloth fell every 30 - 45 min.

5. A dyeing process for a polylactic acid woven fabric according to claim 4, characterized in that The winding density of the open-width beam is 0.2 - 0.4 g / cm 3 .

6. A dyeing process for a polylactic acid woven fabric according to claim 4, characterized in that, The antistatic agent is a cationic quaternary ammonium salt type antistatic agent.

7. A dyeing process for a polylactic acid woven fabric according to claim 6, characterized in that, The cationic quaternary ammonium salt type antistatic agent is N,N-bis(α-hydroxyethyl)-N-(3’-dodecyloxy-2’-hydroxypropyl) methyl ammonium methyl sulfate.

8. A dyeing process for a polylactic acid woven fabric according to claim 4, characterized in that The preparation process of the starch-modified polylactic acid is as follows: Prepare a 10 - 30% concentration slurry of amylose, then adjust the pH value to 7 - 7.5, then add trimethylsilane, stir evenly, then add polylactic acid nanoparticles and stannous octoate, and heat to 55 - 60°C, stir and react for 3 - 4 h. After drying, dissolve it with CH3Cl, and add methanol for precipitation. Wash the precipitate with methanol and then vacuum dry to obtain the starch-modified polylactic acid.