How to control the setting time of polyester?


Determination of polyester setting process Polyester is […]

Determination of polyester setting process
Polyester is a kind of thermoplastic fiber. In a series of processing processes such as dyeing, due to multiple mechanical actions and multiple stretching, the original width and coil geometry of the fabric are changed, resulting in deformation and shrinkage, even horizontally. The silk is skewed, which seriously affects the quality of the product.
The purpose of heat setting is mainly to heat the polyester knitted fabric under tension, and the fabric is melted at a predetermined temperature, so that the thermal movement of the secondary bond and the molecular segment between the fiber molecules is intensified, so that the molecules can be recombined and arranged. The internal stress is relatively stable.
Therefore, the dimensional stability of the fabric can be improved, the anti-wrinkle performance can be enhanced, and the surface smoothness, strength, anti-pilling and the like of the fabric are also improved.
Control two points
The key to the heat setting process of polyester knit fabric is to control the setting temperature and setting time.
If the heat setting temperature is too low, the short time can cause the surface of the fabric to be uneven, not stiff, and the width of the door is contracted, and the shape is lost. If the setting temperature is too high or the time is too long, the fabric will become hard and brittle. The strength is lowered, the elasticity is lowered, and some of the disperse dyes can be sublimated to cause chromatic aberration, and even the fibers can be melted.

Polyester setting time calculation formula
It has been proved that the suitable setting temperature of the polyester knitted fabric is 180-210 ° C, the setting time is 20-90 s, and the cooling temperature is about 50 ° C.
Can be calculated according to the following formula (calculated according to different shaping machine configurations:
Setting time (s) = shaping length (m) / fabric linear speed (m / min) × 60 various types of polyester knitted fabric on the Z921 type needle plate tenter setting machine, when the setting temperature is 185-190 ° C, its line speed For: polyester warp-knitted mosquito net cloth 10-15m/
Min, polyester warp knitted shirt cloth 12-18m/min, polyester warp, weft, knitted outer cloth 12-20m/min, polyester yarn-dyed jacquard cloth 7-l0m/min.
In the shaping, it should not be neglected that the "tension" and "overfeed" of the fabric should be properly matched.
If the width of the tenter exceeds the width of the fabric, it will cause the shrinkage rate to increase and the strength to drop. If the overfeed is too large or the tension is not equal, it will easily cause the latitudinal wave shape (commonly known as "wood ear side". ), and vice versa will produce streaks in the warp direction. In short, the process conditions such as width, tension and overfeed should be strictly controlled during the operation.

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