Polylactic acid woven fabric sizing process

Abstract

The invention discloses a polylactic acid woven fabric slashing process. The slashing process comprises a warp pretreatment process, a size mixing process, a slashing process and a drying process, the slurry contains starch modified polylactic acid, starch acetate, ethylene glycol, an emulsifier, ammonium dihydrogen phosphate, paraffin, an antistatic agent and a dopamine modified polylactic acid copolymer; the warp yarn is subjected to double dipping and double rolling through a double-size-tank sizing machine, size prepared through the size mixing procedure is injected into a size tank, and the temperature of the size tank is 55-60 DEG C; and performing wet leasing on the sized warp yarns, and drying the warp yarns under the condition of 55-60 DEG C. The polylactic acid filament warp beam is pretreated firstly, then sizing is conducted through the sizing agent containing the modified starch / polylactic acid graft copolymer, the starch acetate and other substances, the method can be suitable for low-temperature sizing of polylactic acid, and the sizing effect can be improved and the end breakage rate can be reduced on the premise that the strength of the polylactic acid filament is not reduced.

Description

Technical Field

[0001] The present invention relates to a sizing process for polylactic acid woven fabrics, belonging to the technical field of polylactic acid sizing. Background Art

[0002] Polylactic acid (PLA) is a chemically synthesized biodegradable polymer material formed by polymerizing small molecule lactic acid fermented from biomass raw materials (such as corn, cassava, sugar beet, sugar cane, straw cellulose, etc.) by microorganisms. It belongs to aliphatic polyester and has a wide and rich raw material source. Polylactic acid (PLA) fiber is a synthetic fiber prepared by spinning process (such as melt spinning, wet spinning, dry spinning, dry-wet spinning, electrospinning, etc.) of polylactic acid (PLA), and generally melt spinning is used. Because it has the advantages of both natural fibers and synthetic fibers, its production process is pollution-free, and it has the characteristics of complete biodegradation and natural biological recycling, and has become the first choice of green environmental protection clothing fabrics attracting global attention. However, the surface of polylactic acid fiber is smooth and its hydrophilicity is poor. The adhesion of traditional sizing agents, such as PVA, to polylactic acid fiber is not high, and it is easy to cause the shedding of the sizing film during weaving, resulting in a high weaving breakage rate. And when the PLA fiber is under the condition of higher than 60°C, its strength will decrease. The sizing temperature of traditional PVA sizing agent is higher than 90°C, which is not suitable for the sizing of polylactic acid filament, and will affect the decrease of the strength of PLA filament. How to develop a sizing process for polylactic acid woven fabrics that can not reduce the strength of PLA filament and has a good sizing effect has become a problem to be solved. Summary of the Invention

[0003] The purpose of the present invention is to provide a sizing process for polylactic acid woven fabrics with a good sizing effect.

[0004] To solve the above technical problems, the purpose of the present invention is achieved as follows:

[0005] A sizing process for polylactic acid woven fabrics according to the present invention includes a warp pretreatment process, a sizing preparation process, a sizing process and a drying process;

[0006] The warp pretreatment process: The warp beam formed after warping the polylactic acid filament by a loose warp warping device is placed in an environment of 40 - 50°C and a relative humidity of 65 - 70% for pre-equilibration for 4 - 6 hours, and the moisture content is adjusted to reach 0.5 - 0.6%;

[0007] 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 the 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;

[0008] 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 squeezing pressure is 15 - 20 KN, the moisture regain is 3 - 5%, and the sizing rate is 12 - 15%;

[0009] The drying process: Conduct wet splitting on the sized warp yarns, and dry the warp yarns at 55 - 60°C.

[0010] On the basis of the above solution and as a preferred solution of the above solution: The winding density of the polylactic acid filament beam is 0.2 - 0.4 g / cm 3 。

[0011] 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.

[0012] 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.

[0013] On the basis of the above solution and as a preferred solution of the above solution: 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 trimethylsilyl, stir evenly, then add polylactic acid nanoparticles and stannous octoate, and heat to 55 - 60°C, stir and react for 3 - 4 h, and obtain the starch-modified polylactic acid after drying.

[0014] The beneficial effects of the present invention are: A warping process for polylactic acid woven fabrics involved in the present invention first pre-treats the polylactic acid filament beam, and then sizes with a sizing agent containing substances such as starch-modified polylactic acid and acetate starch, which can be applicable to low-temperature sizing of polylactic acid. It can improve the sizing effect and reduce the breakage rate without reducing the strength of the polylactic acid filaments. Specific Embodiments

[0015] The present invention will be further described below in conjunction with specific embodiments.

[0016] Embodiment 1

[0017] A sizing process for a polylactic acid woven fabric involved in this embodiment includes a warp pretreatment process, a sizing preparation process, a sizing process, and a drying process.

[0018] The warp pretreatment process: The warp beam formed after warping the polylactic acid filaments using a soft warping machine is placed in an environment of 50°C and a relative humidity of 65% for pre-equilibration for 6 hours, and the moisture content is adjusted to reach 0.5%.

[0019] Further, the winding density of the polylactic acid filament warp beam is 0.4 g / cm 3 .

[0020] The sizing preparation 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, 1 part by mass of ammonium dihydrogen phosphate, add them into the sizing preparation tank, and add water into the sizing preparation tank. While heating and stirring, heat to 100°C at a heating rate of 1.5°C / min, then add 3 parts by mass of paraffin wax, 0.4 parts by mass of antistatic agent, and 5 parts by mass of dopamine-modified polylactic acid copolymer, continue stirring. After complete gelatinization, stop stirring; and 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, and the sizing is obtained.

[0021] 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.

[0022] 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 7.5, then add trimethylsilyl, stir evenly, then add polylactic acid nanoparticles and stannous octoate, and heat to 55°C, stir and react for 4 h, and obtain the starch-modified polylactic acid after drying.

[0023] The sizing process: Use a double-sizing-trough sizing machine to double-dip and double-roll the warp, inject the sizing prepared in the sizing preparation process into the sizing trough, the temperature of the sizing trough 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%.

[0024] The drying process: Conduct wet splitting on the sized warp, and dry the warp at 60°C.

[0025] Example 2

[0026] A sizing process for polylactic acid woven fabric involved in this example includes a warp pretreatment process, a sizing process, a warping process, and a drying process.

[0027] The warp pretreatment process: Place the warp beam formed by warping polylactic acid filaments using a soft warping machine in an environment of 40°C and a relative humidity of 70% for pre-equilibration for 4 hours, and adjust the moisture content to reach 0.6%.

[0028] Further, the winding density of the polylactic acid filament warp beam is 0.2 g / cm 3 。

[0029] 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, and 2 parts by mass of ammonium dihydrogen phosphate, add them into a sizing bucket, and add water into the sizing bucket. Stir while heating, and heat to 100°C at a heating rate of 1°C / min. Then add 5 parts by mass of paraffin, 0.2 part by mass of antistatic agent, and 8 parts by mass of dopamine-modified polylactic acid copolymer, continue to stir. After complete gelatinization, stop stirring; adjust the pH value to 7, then stir and cool down to 60°C. The viscosity of the prepared sizing agent is 4.5 Pa·s, and the sizing agent is obtained.

[0030] 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.

[0031] Further, 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, add trimethylsilyl, stir evenly, then add polylactic acid nanoparticles and stannous octoate, and heat to 60°C, stir and react for 3 h. After drying, starch-modified polylactic acid is obtained.

[0032] The warping process: Use a double-sizing warping machine to double-dip and double-roll the warp. Inject the sizing agent prepared in the sizing process into the sizing tank. The temperature of the sizing tank 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%.

[0033] The drying process: Conduct wet splitting on the sized warp, and dry the warp at 55°C.

[0034] Comparative Example 1

[0035] The difference between the sizing agent used in this comparative example and that in Example 1 is that amylose is used instead of starch-modified polylactic acid.

[0036] For Example 1, Example 2 and Comparative Example 1, the sizing quality before and after is detected respectively, and the yarn after sizing treatment is woven on a Tsudakoma ZAX9100 air-jet loom at a weaving speed of 700 r / min, with warp and weft densities of 130 per 10 cm and 70 per 10 cm respectively, and the specification of the polylactic acid filament being 75D / 36F. Plain weave is used. The results are as shown in the following table:

[0037] Project Example 1 Example 2 Comparative Example 1 Moisture regain detected % 4.2 4.5 2.6 Sizing rate % 14.2 13.6 11.3 Enhancement rate % 19.3 18.5 14.6 Elongation reduction rate % 10.6 11.6 15.8 Number of yarn hairs before / after sizing (3mm) 6 6 10 Number of warp stops per machine-hour 0.6 0.8 1.7 Number of weft stops per machine-hour 2.1 2.0 3.5

[0038] 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 according to the concept of the present invention through logical analysis, reasoning or limited experiments on the basis of the prior art should fall within the protection scope determined by the claims.

Claims

1. A polylactic acid woven fabric sizing process, characterized in that: It includes a warp pretreatment process, a sizing process, a warp sizing process and a drying process; The warp pretreatment process: Place the warp beam formed after warping the polylactic acid filaments with a soft warping device in an environment of 40 - 50 °C and a relative humidity of 65 - 70% for pre - equilibration for 4 - 6 hours, and adjust 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 bucket, and add water into the sizing bucket. 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 to 55 - 60 °C. The viscosity of the prepared sizing agent is 4.5 - 5.5 Pa·s, thus obtaining the sizing agent; The warp sizing process: Use a double - trough warp sizing machine to double - dip and double - squeeze the warp. Inject the sizing agent prepared in the sizing process into the sizing trough. The temperature of the sizing trough 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: Conduct wet splitting on the sized warp, and dry the warp at 55 - 60 °C.

2. The sizing process of a polylactic acid woven fabric according to claim 1, characterized in that, The winding density of the polylactic acid filament beam is 0.2 - 0.4 g / cm 3 .

3. The sizing process of a polylactic acid woven fabric according to claim 1, characterized in that, The antistatic agent is a cationic quaternary ammonium salt type antistatic agent.

4. A polylactic acid woven fabric sizing process according to claim 3, 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.

5. A sizing process for polylactic acid woven fabric according to claim 1, 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.