Low-temperature environment-friendly dyeing process and weaving method of polylactic acid blended fabric

Abstract

The invention relates to a low-temperature environment-friendly dyeing process and weaving method of polylactic acid blended fabric, which comprises the following steps: only pre-dyeing modal yarns in the blended fabric at the dyeing temperature of 60-80 DEG C for 30-60 minutes; polylactic acid yarns do not participate in the dyeing process, and high-temperature treatment is avoided in the whole process; after the dyed modal yarn is washed and dried, the modal yarn and polylactic acid yarn are blended and woven according to a preset proportion; after the gray cloth is woven, a low-temperature water washing process at the temperature of 40 DEG C or below is adopted, shaping treatment is carried out at the temperature of 100-120 DEG C, and the shaping time does not exceed 3 minutes; the dyed modal yarn and the undyed polylactic acid yarn are doubled according to the proportion, and the blended yarn is formed. According to the method, only the modal yarns are pre-dyed, so that the hydrolysis risk of the polylactic acid yarns in the high-temperature dyeing process is avoided, the retention rate of functional indexes such as antibacterial activity and degradability of polylactic acid fibers is increased, and the technical effect of completing dyeing on the premise of not damaging the characteristics of polylactic acid is achieved.

Description

Technical Field

[0001] The invention relates to the field of textile technology, specifically to a low-temperature environmentally friendly dyeing process and weaving method for polylactic acid blended fabrics. Background Art

[0002] Polylactic acid (PLA), a bio-based fiber material, boasts excellent biocompatibility and biodegradability, making it a key research area in the field of bio-based fiber materials both domestically and internationally. Low-temperature spandex is an environmentally friendly, high-performance spandex, processed and shaped at low temperatures. Its production process is clean, low-carbon, and green, requiring no water consumption, and without the addition of DMF, DMAC, or other toxic additives such as amines. The fiber is free of harmful residues, is safe and healthy, and is soft, comfortable, and has excellent resilience.

[0003] Currently, the production of PLA blended fabrics on the market mainly adopts the traditional "weaving and dyeing" process, that is, PLA yarn is first blended with other fibers (such as modal, cotton, etc.) to form a grey cloth, and then the grey cloth is placed in a dyeing vat for high-temperature dyeing (usually at a temperature above 100°C). However, PLA is a heat-sensitive bio-based fiber, and its molecular structure is easily hydrolyzed or degraded in high-temperature and humid environments, leading to the following problems:

[0004] 1. Functionality is damaged: The natural antibacterial, biodegradable, moisture-wicking and other properties of polylactic acid yarn are easily destroyed during the high-temperature dyeing process, affecting the performance of the final fabric.

[0005] 2. Unstable quality: High-temperature dyeing may cause color spots, color differences, hard feel and other problems on the fabric surface, affecting the quality of the finished product.

[0006] 3. High energy consumption and pollution: Traditional dyeing processes consume a lot of water and energy, and the discharged wastewater contains a large amount of chemical additives, which puts great pressure on the environmental protection.

[0007] In existing technologies, some companies have attempted to lower dyeing temperatures or use low-temperature dyes, but this has proven difficult to simultaneously meet the requirements for color fastness, uniformity, and production efficiency. Furthermore, if only one fiber in a blended fabric (such as modal) is dyed while the other fiber (such as polylactic acid) remains its original color, issues such as dyed yarn weaving, blending uniformity, and compatibility with the finishing process must be addressed.

[0008] Therefore, a low-temperature environmentally friendly dyeing process and weaving method of polylactic acid blended fabrics are proposed to solve the above problems. Summary of the Invention

[0009] In view of the deficiencies of the prior art, the application provides a low-temperature environment-friendly dyeing process and weaving method for polylactic acid blended fabric, which avoids the contact of polylactic acid yarn with high temperature by only pre-dyeing modal yarn and optimizing the subsequent process, and reduces energy consumption and pollution, solving the problem that in the prior art, some enterprises try to reduce the dyeing temperature or use low-temperature dyes, but it is difficult to meet the requirements of color fastness, uniformity and production efficiency at the same time. In addition, if only one fiber (such as modal) in the blended fabric is dyed, and the other fiber (such as polylactic acid) remains the original color, the problems of colored yarn weaving, blending uniformity and adaptation of finishing process need to be solved.

[0010] To achieve the above-mentioned purpose, the application provides the following technical scheme: a low-temperature environment-friendly dyeing process for polylactic acid blended fabric, comprising the following steps:

[0011] S1, only pre-dyeing modal yarn in the blended fabric, the dyeing temperature is 60-80℃, and the dyeing time is 30-60 minutes;

[0012] S2, polylactic acid yarn does not participate in the dyeing process, and avoids high temperature treatment throughout the process;

[0013] S3, after the modal yarn dyed is washed and dried, it is blended and woven with polylactic acid yarn according to a predetermined ratio;

[0014] S4, after the grey fabric is woven, a low-temperature washing process below 40℃ is adopted, and a setting treatment is carried out at a temperature of 100-120℃, and the setting time is not more than 3 minutes.

[0015] Further, the dyeing of the modal yarn uses environment-friendly reactive dyes, the dye concentration is 1-5% (o.w.f), the bath ratio is 1:10-1:15, and 0.5-1g / L of low-temperature dyeing agent is added.

[0016] Further, the low-temperature dyeing agent is an anionic surfactant or a non-ionic penetrant, preferably a fatty alcohol polyoxyethylene ether or an alkyl sulfonate.

[0017] Further, the blending ratio of the modal yarn and the polylactic acid yarn is: modal 50-70%, polylactic acid 30-50%, and the preferred ratio is modal 60% and polylactic acid 40%, the modal yarn needs to be adjusted in twist after dyeing, the twist range is 300-500 twists per meter, and the twist direction is S twist or Z twist, so as to ensure the weaving adaptability.

[0018] Further, the blended weaving uses a rapier loom or an air-jet loom, the warp density is 80-120 ends / cm, and the weft density is 60-100 ends / cm, so as to ensure the fabric structure stability and the fabric uniformity.

[0019] Furthermore, in the low-temperature washing process, the washing water temperature is 30-40°C, the washing time is 10-20 minutes, and 1-2g / L of environmentally friendly detergent is added to reduce fiber damage. In the setting treatment, the setting temperature is 100-120°C, the machine speed is 20-30 meters / minute, and 1-2% of polylactic acid special softener is added to improve the feel and functionality of the fabric.

[0020] A method for weaving a polylactic acid blended fabric, comprising weaving the polylactic acid blended fabric using a low-temperature environmentally friendly dyeing process for the polylactic acid blended fabric, wherein the weaving method is specifically as follows:

[0021] S1, paralleling the dyed modal yarn and the undyed polylactic acid yarn in proportion to form a blended yarn;

[0022] S2, using a rapier loom or an air jet loom for weaving, the warp density is 80-120 yarns / cm, and the weft density is 60-100 yarns / cm;

[0023] S3. The woven grey cloth is washed and set at low temperature, with the washing temperature ≤ 40℃ and the setting temperature ≤ 120℃.

[0024] Furthermore, the twist of the blended yarn is 300-500 twists / m, and the twist direction is S twist or Z twist to ensure yarn strength and weaving efficiency. An electronic jacquard device or a multi-arm opening mechanism is used in the weaving process to ensure the accuracy and consistency of the fabric pattern.

[0025] Preferably, the fabric has the following performance indicators:

[0026] Color fastness (dry / wet friction) ≥ level 4;

[0027] Breaking strength ≥300N;

[0028] Bacterial inhibition rate ≥ 90% (tested according to AATCC100 standard);

[0029] The biodegradability complies with ISO14855 standards.

[0030] Compared with the existing technology, the technical solution of this application has the following beneficial effects:

[0031] 1. The present invention avoids the risk of hydrolysis of polylactic acid yarn during high-temperature dyeing by pre-dyeing only the modal yarn, thereby improving the retention rate of functional indicators such as the antibacterial property and degradability of the polylactic acid fiber, and achieving the technical effect of completing dyeing without damaging the characteristics of polylactic acid. By controlling the dyeing temperature of the modal yarn to 60-80°C, the energy consumption of traditional high-temperature dyeing is reduced, the organic matter content in the wastewater is reduced, and the environmental friendliness of the process is enhanced. By adding a low-temperature dyeing accelerator, the dyeing rate and color fastness of reactive dyes under low-temperature conditions are improved, solving the common uniformity problem of low-temperature dyeing and achieving a color effect equivalent to that of traditional high-temperature dyeing.

[0032] 2. The present invention balances the softness and strength of the fabric by optimizing the blending ratio, increases the breaking strength, and maintains the biodegradable properties of polylactic acid. By adjusting the twist of the modal yarn, the weaving adaptability of the blended yarn is enhanced, the breakage rate in the weaving process is reduced (reduced by 30%), and production efficiency is improved. By adopting rapier / air-jet looms and high-density weaving, the uniformity of the surface of the grey cloth is improved, and the color and color difference problems caused by traditional dyeing processes are avoided, meeting the appearance standards of high-end fabrics. Through low-temperature washing and shaping processes, the risk of thermal damage to polylactic acid fibers is reduced, the feel of the finished product is improved, and energy consumption is reduced.

[0033] 3. By adding a special PLA softener, this invention improves the smoothness and drape of the fabric after low-temperature setting, solving the problem of PLA fibers becoming hard, and achieving wearability similar to that of conventional polyester fabrics. By integrating yarn dyeing with a low-temperature integrated process, the fabric achieves multiple standards for color fastness, antibacterial rate, and biodegradability, filling a gap in low-temperature, environmentally friendly dyeing technology for PLA blended fabrics. Electronic jacquard or dobby shedding mechanisms improve the precision of complex pattern weaving, expanding the application of this process in high-end fields such as fashion and medicine. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 To invent a low-temperature environmentally friendly dyeing process flow chart for polylactic acid blended fabrics;

[0035] Figure 2 The present invention is a flow chart of a weaving method for inventing a polylactic acid blended fabric. DETAILED DESCRIPTION

[0036] The following will clearly and completely describe the technical solutions in the embodiments of the invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0037] See also Figure 1-2 In this embodiment, a low-temperature environmentally friendly dyeing process for a polylactic acid blended fabric comprises the following steps:

[0038] S1. Only the modal yarn in the blended fabric is pre-dyed, the dyeing temperature is 60°C, the dyeing time is 30 minutes, the modal yarn is dyed with environmentally friendly reactive dyes, the dye concentration is 1% (owf), the bath ratio is 1:10, and 0.5-1g / L of a low-temperature accelerator is added, the low-temperature accelerator is an anionic surfactant or a non-ionic penetrant, preferably a fatty alcohol polyoxyethylene ether or an alkyl sulfonate, the blending ratio of the modal yarn and the polylactic acid yarn is: modal 50%, polylactic acid 30%, preferably modal 60%, polylactic acid 40%, the modal yarn needs to be twisted after dyeing, the twist range is 300 twists / m, and the twist direction is S twist or Z twist to ensure weaving adaptability;

[0039] S2, PLA yarn does not participate in the dyeing process and avoids high temperature treatment throughout the process;

[0040] S3, the dyed modal yarn is washed and dried, and then blended with polylactic acid yarn in a predetermined ratio. The blended yarn is woven using a rapier loom or an air-jet loom with a warp density of 80 yarns / cm and a weft density of 100 yarns / cm to ensure fabric structural stability and cloth uniformity;

[0041] S4. After the grey cloth is woven, it is subjected to a low-temperature washing process below 40°C and a setting treatment at 100°C for no more than 3 minutes. In the low-temperature washing process, the washing water temperature is 30°C and the washing time is 10 minutes. 1g / L of an environmentally friendly detergent is added to reduce fiber damage. In the setting treatment, the setting temperature is 120°C and the machine speed is 30 m / min. 1-2% of a special polylactic acid softener is added to enhance the fabric's feel and functionality.

[0042] A method for weaving a polylactic acid blended fabric, comprising weaving the polylactic acid blended fabric using a low-temperature environmentally friendly dyeing process for the polylactic acid blended fabric, wherein the weaving method is specifically as follows:

[0043] S1, the dyed modal yarn and the undyed polylactic acid yarn are paralleled in proportion to form a blended yarn, wherein the twist of the blended yarn is 500 twists / m and the twist direction is S twist or Z twist to ensure yarn strength and weaving efficiency;

[0044] S2. The weaving is carried out using a rapier loom or an air-jet loom, with a warp density of 80-120 yarns / cm and a weft density of 100 yarns / cm. An electronic jacquard device or a dobby shedding mechanism is used in the weaving process to ensure the accuracy and consistency of the fabric pattern.

[0045] S3. The woven grey cloth is subjected to low-temperature washing and low-temperature setting treatments, with the washing temperature being 40°C and the setting temperature being 120°C.

[0046] Specifically, the fabric has the following performance indicators:

[0047] Color fastness (dry / wet friction) is level 4;

[0048] The breaking strength is 300N;

[0049] The antibacterial rate is 90% (tested according to AATCC100 standard);

[0050] The biodegradability complies with ISO14855 standards.

[0051] Example 1: Preparation of polylactic acid / modal (40 / 60) blended fabric

[0052] 1. Raw material preparation: polylactic acid (PLA) yarn 40%, 1.5D×38mm, modal yarn 60%, 1.2D×40mm.

[0053] 2. Modal yarn dyeing:

[0054] Using the cheese dyeing process:

[0055] Dye: environmentally friendly reactive dye (3% owf);

[0056] Dyeing temperature: 70±2℃;

[0057] Staining time: 45 minutes;

[0058] Bath ratio: 1:12;

[0059] 0.8 g / L fatty alcohol polyoxyethylene ether was added as a dyeing accelerator.

[0060] 3. Yarn post-treatment: washing temperature 40℃, drying temperature 80℃, twist adjustment 400 twists / m (S twist)

[0061] 4. Weaving process:

[0062] Loom type: rapier loom;

[0063] Warp density: 100 strands / cm;

[0064] Weft density: 80 threads / cm;

[0065] Organization structure: plain weave;

[0066] 5. Finishing: washing water temperature 35 ℃, washing time 15 minutes, setting temperature 110 ℃, setting time 2 minutes, add 1.5% polylactic acid special softener

[0067] 6. Effect: Color fastness 4-5 level, breaking strength 320N, antibacterial rate 92%, energy consumption reduced by 42%.

[0068] Example 2: Preparation of polylactic acid / modal (30 / 70) blended fabric

[0069] 1. Raw material preparation: polylactic acid (PLA) yarn 30%, 1.8D×40mm, modal yarn 70%, 1.4D×38mm.

[0070] 2. Modal yarn dyeing: using the package dyeing process, environmentally friendly reactive dyes (4% owf), dyeing temperature: 65±2°C, dyeing time: 50 minutes, bath ratio: 1:15, adding 1.0 g / L alkyl sulfonate as a dyeing accelerator.

[0071] 3. Yarn post-treatment: washing temperature: 35℃, drying temperature: 75℃, twist adjustment: 450 twists / m (Z twist).

[0072] 4. Weaving process: Loom type: air-jet loom, warp density: 110 threads / cm, weft density: 90 threads / cm, structure: twill.

[0073] 5. Finishing: washing water temperature: 30℃, washing time: 20 minutes, setting temperature: 105℃, setting time: 2.5 minutes, add 2.0% polylactic acid special softener

[0074] 6. Effect: Color fastness: Level 4, breaking strength: 350N, antibacterial rate: 95%, energy consumption reduction: 45%.

[0075] Example 3: Preparation of polylactic acid / modal (50 / 50) blended fabric

[0076] 1. Raw material preparation: Polylactic acid (PLA) yarn: 50%, 1.2D×35mm, Modal yarn: 50%, 1.0D×42mm.

[0077] 2. Modal yarn dyeing: adopt the package dyeing process, environmentally friendly reactive dyes (2% owf), dyeing temperature: 75±2℃, dyeing time: 40 minutes, bath ratio: 1:10, add 0.5g / L non-ionic penetrant as a dyeing accelerator.

[0078] 3. Yarn post-treatment: washing temperature: 45℃, drying temperature: 85℃, twist adjustment: 350 twists / m (S twist).

[0079] 4. Weaving process: Loom type: rapier loom, warp density: 90 threads / cm, weft density: 70 threads / cm, structure: satin.

[0080] 5. Finishing: washing water temperature: 40℃, washing time: 10 minutes, setting temperature: 115℃, setting time: 1.5 minutes, add 1.0% polylactic acid special softener

[0081] 6. Effect: Color fastness: level 4-5, breaking strength: 300N, antibacterial rate: 90%, energy consumption reduction: 38%.

[0082] By adopting the above technical solution, the following examples are compared and analyzed:

[0083] parameter Example 1 Example 2 Example 3 blending ratio 40 / 60 30 / 70 50 / 50 Dyeing temperature (℃) 70 65 75 Setting temperature (℃) 110 105 115 Breaking strength (N) 320 350 300 Antibacterial rate (%) 92 95 90 Energy consumption reduction (%) 42 45 38

[0084] in conclusion:

[0085] 1) Example 2 (30 / 70 ratio) exhibits the best overall performance and is particularly suitable for high-end medical textiles;

[0086] 2) Example 1 (40 / 60 ratio) achieves the best balance between functionality and production cost and is suitable for mass sportswear;

[0087] 3) Although Example 3 (50 / 50 ratio) has slightly lower strength, it has the best degradability and is suitable for the field of environmentally friendly packaging materials.

[0088] In summary, this low-temperature, environmentally friendly dyeing and weaving process for PLA blended fabrics, by pre-dyeing only the modal yarn, avoids the risk of hydrolysis during the high-temperature dyeing process. This improves the retention of functional properties of the PLA fiber, such as antibacterial properties and biodegradability, achieving the technical effect of dyeing without compromising the properties of the PLA. By optimizing the blending ratio, the softness and strength of the fabric are balanced, increasing the breaking strength while maintaining the biodegradability of the PLA. By adjusting the twist of the modal yarn, the weaving adaptability of the blended yarn is enhanced, the yarn breakage rate is reduced, and production efficiency is improved. The addition of a PLA-specific softener improves the smoothness and drape of the fabric after low-temperature setting, addressing the problem of PLA fiber hardening and achieving wearability similar to that of conventional polyester fabrics. The use of electronic jacquard or dobby shedding mechanisms improves the precision of weaving complex patterns, expanding the application of this process in high-end applications such as fashion and medical applications.

[0089] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0090] While embodiments of the invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and alterations may be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A low-temperature environmentally friendly dyeing process for polylactic acid blended fabrics, characterized in that: The following steps are involved: S1. Only the modal yarn in the blended fabric is pre-dyed at a temperature of 60-80°C and a dyeing time of 30-60 minutes; S2, PLA yarn does not participate in the dyeing process and avoids high temperature treatment throughout the process; S3, after dyeing modal yarn is washed and dried, it is blended with polylactic acid yarn in a predetermined ratio; S4. After the grey cloth is woven, it is washed in a low-temperature water process below 40°C and then shaped at 100-120°C for no more than 3 minutes.

2. The low-temperature environmentally friendly dyeing process for polylactic acid blended fabrics according to claim 1, characterized in that: The modal yarn is dyed with environmentally friendly reactive dyes, with a dye concentration of 1-5% (owf) and a bath ratio of 1:10-1:15, and 0.5-1 g / L of a low-temperature dyeing accelerator is added.

3. The low-temperature environmentally friendly dyeing process for polylactic acid blended fabrics according to claim 1, characterized in that: The low-temperature dyeing accelerator is an anionic surfactant or a nonionic penetrant, preferably a fatty alcohol polyoxyethylene ether or an alkyl sulfonate.

4. The low-temperature environmentally friendly dyeing process for polylactic acid blended fabrics according to claim 1, characterized in that: The blending ratio of the modal yarn and the polylactic acid yarn is: 50-70% modal, 30-50% polylactic acid, preferably 60% modal, 40% polylactic acid. The modal yarn needs to be twisted after dyeing, with a twist range of 300-500 twists / m and an S twist or Z twist to ensure weaving adaptability.

5. The low-temperature environmentally friendly dyeing process for polylactic acid blended fabrics according to claim 1, characterized in that: The blended fabric is produced by using a rapier loom or an air jet loom, with a warp density of 80-120 threads / cm and a weft density of 60-100 threads / cm, so as to ensure the structural stability and uniformity of the fabric.

6. The low-temperature environmentally friendly dyeing process for polylactic acid blended fabrics according to claim 1, characterized in that: In the low-temperature washing process, the washing water temperature is 30-40°C, the washing time is 10-20 minutes, and 1-2g / L of environmentally friendly detergent is added to reduce fiber damage. In the setting treatment, the setting temperature is 100-120°C, the machine speed is 20-30 meters / minute, and 1-2% of polylactic acid special softener is added to improve the feel and functionality of the fabric.

7. A method for weaving a polylactic acid blended fabric, comprising weaving the polylactic acid blended fabric using the low-temperature environmentally friendly dyeing process for the polylactic acid blended fabric according to any one of claims 1 to 6, characterized in that: Described weaving method is specifically as follows: S1, paralleling the dyed modal yarn and the undyed polylactic acid yarn in proportion to form a blended yarn; S2, using a rapier loom or an air jet loom for weaving, the warp density is 80-120 yarns / cm, and the weft density is 60-100 yarns / cm; S3. The woven grey cloth is washed and set at low temperature, with the washing temperature ≤ 40℃ and the setting temperature ≤ 120℃.

8. The method for weaving a polylactic acid blended fabric according to claim 7, characterized in that: The twist of the blended yarn is 300-500 twists / m, and the twist direction is S twist or Z twist to ensure yarn strength and weaving efficiency. An electronic jacquard device or a multi-arm opening mechanism is used in the weaving process to ensure the accuracy and consistency of the fabric pattern.

9. The method for weaving a polylactic acid blended fabric according to claim 7, characterized in that: The fabric has the following performance indicators: Color fastness (dry / wet friction) ≥ level 4; Breaking strength ≥300N; Bacterial inhibition rate ≥ 90% (tested according to AATCC100 standard); The biodegradability complies with ISO14855 standards.

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