Semi Dull Filament Yarn Nylon 6, is widely used in warp knitting, machine weaving, luggage fabrics, sportswear, underwear, and industrial textiles. Downstream weaving and dyeing factory customers are most concerned about batch stability, breakage rate, and dyeing consistency. A comprehensive factory inspection can reduce complaints such as broken wires, color differences, and inconsistent shrinkage in the subsequent process. Below is a complete introduction to the routine factory inspection items for semi dark filament nylon 6, to assist the purchaser in incoming material acceptance and supplier quality control.
1、 Physical and mechanical performance testing (core mandatory item)
1. Linear density and coefficient of variation (CV) of linear density
According to the GB/T14343 standard, measure the actual denier/dtex value of the silk, calculate the deviation of linear density and CV value. Large fluctuations in line density can directly cause uneven fabric weight and stripe marks on the fabric surface. The procurement and acceptance of semi dark nylon 6 filament generally agree on the range of linear density deviation, and the lower the CV value, the more uniform the filament.
2. Fracture strength and elongation at break
According to GB/T14344 testing, it reflects the ability and toughness of the silk thread to withstand tensile force. Insufficient strength can lead to breakage during the weaving process; The elongation rate is unstable, and the stretch rebound of the finished fabric is inconsistent. Sports fabrics, seat belts, luggage fabrics, etc. have higher requirements for strength indicators.
3. Boiling water shrinkage rate
GB/T6505 standard testing is a crucial indicator for nylon filament. Nylon 6 will shrink when exposed to hot water, and the shrinkage rate fluctuates greatly in boiling water. After dyeing and shaping, the fabric is prone to uneven length and wrinkles. Customers will specify corresponding shrinkage rate ranges for different application scenarios.
4. Uniformity of strip (strip CV)
Use the Uster strip dryer to detect and evaluate small fluctuations in wire thickness. The semi dark nylon 6 filament with poor quality is prone to hidden and horizontal stripes on the fabric surface after weaving, and has obvious color difference defects after dyeing. It is a key control indicator for high-end fabrics.
2、 Processing adaptation indicators (affecting weaving, elasticity, dyeing)
1. Oil content
GB/T6504 method testing. The content of spinning oil on the surface of the silk directly affects the smoothness of rewinding. Low oil content, high friction of the fiber bundle, easy static electricity and wire breakage; If the oil content is too high, subsequent dyeing will produce oil spots and color spots. Different weaving techniques (warp knitting, machine weaving) need to be matched with corresponding oil content ranges.
2. regain
GB/T6503 testing. Nylon belongs to hygroscopic fibers, and its moisture regain varies with environmental temperature and humidity. Excessive moisture regain can cause the silk cake to adhere and mold easily; Low moisture regain, increased static electricity, and increased weaving breakage. Both warehouse storage and incoming material inspection need to monitor this.
3. Network nodes (number of network points)
Network silk is used to detect the number and uniformity of network nodes. Insufficient network points make it easy for fiber bundles to diverge, increasing the difficulty of weaving; Too many network points cause the silk to harden, affecting the texture of the fabric.
4. Uniformity of dyeing
FZ/T50008 standard is a key testing item for semi dark filament nylon 6. The uniformity of semi extinction TiO ₂ addition directly affects the dyeing effect. Uneven dyeing can result in color spots and variations in the fabric. For ready to wear fabrics and stretch fabrics, this indicator directly determines the yield rate.
3、 Semi extinction exclusive indicator: titanium dioxide (TiO ₂) content
Semi dark nylon 6 achieves a matte effect by adding titanium dioxide matting agent, which is different from glossy and fully matte silk. Detect TiO ₂ content according to FZ/T 50027. The TiO ₂ content is unstable, and the luster of different silk cakes in the same order may vary in depth, resulting in light and dark stripes on the fabric. This is a key inspection item unique to semi dark filament, and many purchasing customers overlook this indicator, resulting in inconsistent gloss of the finished product.
4、 Appearance and roll inspection (visual sampling of each tube)
According to the GB/T16603-2025 standard for nylon stretch yarn, inspect the appearance of the yarn cake under standard light source:
Hair strands, broken ends, stiff strands, pulp blocks, oil stains, rust spots
Silk cake forming: uneven end face, collapsed edge, detachment, spider mesh silk
Tube damage, integrity of label information
Appearance defects can directly cause broken ends and fabric defects in the back winding process. The inspection adopts a sampling plan and determines qualified batches according to AQL standards.
5、 Optional customized testing items (according to customer needs)
1. Friction coefficient: Evaluate the friction between the wire and the guide wire, predict the risk of weaving breakage
2. Sun and aging resistance tests: Requirements for outdoor fabrics, tents, and sunshade fabrics
3. Color fastness test: Color fastness to soap washing and rubbing (silk products)
4. Heavy metal and harmful substance detection: OEKO-TEX matching detection, used for close fitting clothing, mother and baby fabrics
5. Single filament separation and cross-sectional morphology inspection: special ultra-fine denier products
6、 Overview of Inspection Process
Production sampling → constant temperature and humidity laboratory humidity balance → instrument performance testing → appearance and lighting inspection → data comparison specification sheet → grading judgment (superior/first-class/qualified) → issuing quality inspection report and providing batch testing records along with the goods.
7、 Why pay attention to the incoming inspection of Semi Dull Filament Yarn Nylon 6?
Many textile factories encounter problems such as uneven fabric patterns, unstable shrinkage rates, and a large number of broken ends in warp knitting, which are caused by incomplete testing of the long fibers entering the factory. In addition to conventional strength and shrinkage indicators, the uniformity of TiO ₂ matting agent is a unique risk point for semi dark nylon 6. Early detection reduces losses in subsequent processes and stabilizes fabric quality.
