Effect of Spinneret Stretch Ratio on Fiber Quality and Spinnability
Influence of Spinneret Stretch Ratio on Spinnability of Acrylic Fiber Formed by Sodium Thiocyanate Method
Spinneret Stretch Ratio φa(%) | -75 | -70 | -60 | -45 |
Fineness (dtex) | 6.60 | 6.94 | 6.99 | 7.20 |
Breaking strength (cN/dtex) | 2.46 | 2.05 | 1.77 | 1.70 |
Break elongation (%) | 56.6 | 51.3 | 61.1 | 53.9 |
Hook strength(cN/dtex) | 1.25 | 1.29 | 0.92 | 1.00 |
Hook slongation(%) | 34.4 | 38.2 | 27.3 | 27.0 |
Compressive elasticity (%) | 28.27 | 30.1 | 25.3 | 26.06 |
Non-spinning | Rare fuzz | normal | Little fiber break and fuzz | Fiber break, fuzz and winding roller |
When φa is constant, if B0 is different, then φf is different (Not only the values are different, but the signs may also be reversed); When φa is a negative value and φf is a positive value, if the value of φa is unreasonable, not only will the smooth progress of spinning be affected, but the quality of the finished fiber will also decrease.
Empirical relationship:
τ – Loosening time; E - Elastic Modulus; S* - Breaking strength;
VLmax - Maximum velocity of the first guide roller: Vf↑ VLmax↑(smaller range)
The buffer range of normal spinning ΔVL= VLmax - VL
ΔVL↑ Forming stability ↑
V0 is constant, B0↑ Vf↑ VLmax↑ ΔVL↑, i.e. Spinnability↑
The smallest extrusion swell ratio corresponds to the best spinnability.
For example: spinning of PAN-NaSCN
Temperature of stock solution: 32~35℃, velocity of spinning: 60~70m/min
Temperature of stock solution: 60~70℃, velocity of spinning: 200m/min
T↑ τ↓ B↓ VL can be increased.