1. Fiber properties:
The higher the fiber strength, the finer the fineness and the longer the length, the higher the strength of the polyester filament.
The natural twist of cotton fiber and the crimping of wool and chemical fibers will increase the cohesion between the fibers when the twist of polyester filaments is not large, thereby increasing the strength of polyester filaments.
The linter content has a greater impact on the strength of polyester filaments. Among cotton yarns, the rate of short-staple under 16 mm increases by 1%, and the strength of cotton yarn decreases by 1 to 2%.
2.Polyester filament structure:
The fiber transfers inside and outside in the direction of the yarn radius: there are many internal and external transfers, and the strength of polyester filaments can be increased when the structure is uniform; when the fibers are arranged in layers and are folded, buckled, and hooked, the strength of polyester filaments decreases; polyester filament twist: at the critical twist Below the degree of twist, the strength of polyester filament increases with the increase of twist, and after the critical twist, it decreases with the increase of twist. Yarn uniformity: Polyester filament strength unevenness. Yarn thick knots, details, neps: pure cotton yarn is easy to break at the details and large neps; polyester-cotton yarn is easy to break at the turning points of thick and thick details. Blending uniformity: Fibers of different types of properties are uniformly mixed in the vertical and horizontal directions.
3. Spinning method:
Polyester filaments spun by different spinning methods have obvious differences in strength due to their different structures. The strength of thick airflow yarn is about 5-10% lower than that of ring yarn of the same size, but the airflow yarn has uniform fineness, and the weakest node is not lower than that of ring yarn. The strength of electrostatic spinning is similar to that of air yarn. Self-twisted yarn: In-phase self-twisted yarn has low strength due to the existence of no twisted areas on the yarn; out-of-phase self-twisted yarns have increased strength due to staggered non-twisted areas on the yarn. The strength of the twisted yarn is further improved due to the reasonable distribution of the twist.
4. Blending ratio:
In the two-component blended yarn (T/C), when the blending ratio of one component (T) gradually increases from zero, the strength of the blended yarn generally decreases. After reaching the lowest value, if you continue to increase this component (T) ), the yarn strength gradually increases. The greater the difference between the elongation at break of the two mixed fibers, the more obvious this trough phenomenon of strength.
5. Big temperature and humidity:
The higher the temperature, the lower the strength of polyester filament; the higher the relative humidity, the higher the moisture regain of polyester filament, the higher the strength of cotton and linen polyester filament, the lower the strength of wool and rayon polyester filament. Therefore, the strength test should be carried out after equilibrium under the specified standard state (temperature 20℃, relative temperature 65%), otherwise the measured strength must be corrected by temperature and moisture regain.
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