What are the conventional textile processes suitable for polylactic acid fibers-Suzhou Kingcharm New Materials Corp.

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What are the conventional textile processes suitable for polylactic acid fibers

source：www.kingcharmgroup.com | Release time：2026-04-14

Polylactic acid (PLA) fiber, as a nationally recognized biodegradable green synthetic fiber, has a chemical structure and thermoplastic characteristics that are compatible with the entire textile process system. It can be industrially applied in conventional textile processing equipment such as cotton spinning, synthetic fiber spinning, weaving, knitting, dyeing and finishing, and non-woven. The core process route and technical specifications are as follows:
1、 Spinning molding process
Poly (lactic acid) fibers are produced using melt spinning as the mainstream industrial process, providing qualified fiber raw materials for textile processing and meeting the requirements of the "Technical Specification for Bio based Poly (lactic acid) Fiber Industry" standard.
melt spinning
After drying and removing water, high-purity polylactic acid resin (L-PLA content ≥ 98%) is melted and plasticized at 165 ℃ -175 ℃. It is extruded through a metering pump and a spinneret, cooled and solidified by side blowing to form primary fibers, and then subjected to multi-stage stretching (stretching ratio 3.0-5.0 times), heat setting (100 ℃ -120 ℃), oiling, winding to produce polylactic acid filament, short fiber, shaped fiber, hollow fiber and other products. This process is solvent-free, efficient, and cost-effective, making it a production line technology for tens of thousands of tons.
Fiber morphology specifications
Short fiber: with a linear density of 1.2D-3.3D, lengths of 38mm, 51mm, and 65mm, suitable for cotton and wool spinning systems.
Long filament: 50D-300D, can be processed into stretch yarn (FDY) and stretch deformation yarn (DTY), meeting the needs of weaving and knitting.
2、 Spinning process
Polylactic acid fibers can be spun or blended on conventional spinning equipment such as cotton spinning, wool spinning, air flow spinning, and vortex spinning. The "Technical Specification for Processing Polylactic Acid Fiber Yarn" is implemented, and the core process and parameters are as follows:
process flow
Clearing cotton → carding → pre drawing → combing (optional) → drawing → roving → fine yarn → winding.
Key points of process control
Clearing cotton: Reduce the speed of the beater (600-800r/min) to minimize fiber damage and static electricity, and adopt the process of multiple combing, less beating, and light weight.
Cotton combing: Xilin speed 280-320r/min, cover speed 80-120mm/min, control fiber combing degree, reduce fuzz.
Coarse process: 6-8 pieces are combined for the drawing process, with a yarn twist coefficient of 90-95 and a flexible control of the stretching ratio (4.0-4.5 times in the front area and 1.65-1.70 times in the back area).
Fine yarn: spindle speed of 14000-16000r/min, roller spacing adapted to fiber length, reducing breakage, resulting in a yarn strength of 3.5-5.0cN/dtex.
Blended adaptation: It can be blended with fibers such as cotton, wool, linen, lyocell, modal, viscose, etc., with a blending ratio of 10% -80%, to improve the texture and performance of the fabric.
3、 Machine weaving process (conventional weaving system)
Suitable for various conventional weaving machines such as jet, rapier, water jet, shuttle, etc., in accordance with the "Processing Specification for Polylactic Acid Fiber Woven Fabrics":
Pre preparation process
Winder: Electronic yarn cleaning is used, with a groove drum speed of 600-800r/min to reduce yarn friction and fuzzing.
Whole warp: tension evenly controlled (0.35-0.45cN/dtex), winding density 0.2-0.4g/cm ³, using a loose warp.
Scaling: Neutral low viscosity sizing agent (PVA+modified starch) is used, with a sizing tank temperature of ≤ 95 ℃, a drying temperature of ≤ 110 ℃, a sizing rate of 12% -15% , and strong alkali sizing agents are strictly prohibited.
Weaving process
The weaving machine has a speed of 450-600r/min (jet) and 200-350r/min (sword), and the weaving mouth is regularly sprayed with anti-static agent to control the humidity in the workshop from 55% to 65% and reduce static interference.
4、 Knitting technology (conventional knitting system)
Suitable for conventional knitting equipment such as circular knitting machines, warp knitting machines, and horizontal knitting machines, suitable for the production of various fabrics such as sweatshirts, ribbed fabrics, looped fabrics, and mesh fabrics
Key process points
Smooth processing of yarn channels reduces friction coefficient and minimizes pilling.
The needle density and tension are adapted to the fiber characteristics, and the coil length is 0.25-0.35mm to control the fabric density and elasticity.
After the fabric is removed from the machine, it should be stored loosely in a timely manner to avoid shrinkage and deformation caused by high temperature stacking.
5、 Dyeing and Finishing Process (Core Specifications, Official Temperature Control Standards)
According to the "Technical Regulations for Dyeing and Finishing of Polylactic Acid Fiber", based on the core principles of low temperature, neutral/weak acidity, and no strong alkali, it is suitable for conventional dyeing and finishing equipment:
preprocessing
Using neutral/weak alkaline (pH 7.0-8.0), temperature ≤ 80 ℃ , using non-ionic surfactants to remove oil and impurities, strictly prohibiting strong alkaline boiling, silk polishing, chlorine bleaching, to avoid fiber hydrolysis and brittleness.
dyeing
Dyes: Disperse dyes (E-type, SE type) are selected, which are compatible with the polylactic acid ester bond structure and have excellent uniformity.
Temperature: 100 ℃ -110 ℃, keep warm for 20-30 minutes, strictly prohibit exceeding 120 ℃ to prevent fiber softening, shrinkage, and strength loss.
Dyeing bath: pH 5.0-6.0 (weakly acidic), to avoid acid-base imbalance leading to ester bond hydrolysis.
Heat setting (key)
The setting temperature is 110 ℃ -130 ℃, the time is 30-45 seconds, and the feeding rate is 6% -10%. The door width and dimensional stability are controlled. If it exceeds 140 ℃, it is prone to yellowing and brittleness.
post-arrangement
It can perform conventional functional finishing such as softness, hydrophilicity, anti-static, antibacterial, UV resistant, flame retardant, etc. The finishing agent needs to be neutral/weakly acidic, and the drying temperature should be ≤ 100 ℃.
6、 Non woven fabric process (conventional non-woven system)
Adapt to conventional non-woven processes such as water jet, hot rolling, needle punching, and hot air to produce environmentally friendly non-woven products:
Spunlace: water pressure 80-120bar, temperature ≤ 80 ℃, made into high soft wipes, facial mask base material.
Hot rolling: temperature 130 ℃ -140 ℃, pressure 3-5 MPa, producing environmentally friendly packaging and geotextile.
Acupuncture/Hot Air: Low temperature thermosetting, suitable for hygiene products and filter materials.

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