The present invention relates to a process for preparing a textured yarn

Draw Texturing Yarns
Draw Texturing Yarns are high quality, textured yarns. They offer improved pill resistance, dimensional and crease resistance, fuller appearance and better sewability.

The present invention relates to a process for preparing a textured yarn from a feed yarn that is obtained by melt spinning at a speed of 3000 - 5000 meters per minute. It entails drawing and false-twist texturing of such feed yarn simultaneously or sequentially at a draw ratio of 1.05 - 1.30X using a heat-setting temperature of 170deg - 240degC.

Tenacity
In order to obtain textured yarns of good tenacity, especially for the industrial application, it is necessary to use feed yarns having excellent birefringence values and titers. The birefringence values should be preferably below about +2 x 10-3.

It is also important to avoid using feed yarns which have excessive elasticity, because such elongation is induced during the draw-texturing process due to the deformation of the cross section of the feed yarns.

Thus, a special care should be exercised when threading up the feed yarns to the draw-texturing machine. It is essential that the yarns are drawn under the conditions of a hot pin temperature and a draw ratio that is not too high.

The tenacity of the textured yarns is influenced by the drawing and false-twist texturing operations conducted simultaneously. The twist level is preferably set at about 0.9 - 1.0 to achieve a textured yarn suited for most applications.

Elongation
The elongation of materials is a very important property to consider in the manufacturing of textile products. It provides information about how a material will respond to forces when they are applied.

The most common method for assessing elongation is the tensile test. This test uses a pulling force to stretch the material and measures how much it can resist before it fractures.

In the manufacturing of ropes and cordage, high-speed drawing is a necessary step to produce strong, low-elongation yarns. The higher the speed, the greater the stress on the process and equipment.

This can result in broken filaments, threadline breaks, and poor package formation, all of which reduce the quality of a yarn.

The tensile test is an excellent tool for evaluating a material’s ductility as well as strength. It can also be used to predict how a material will behave in certain applications, such as ropes and cordage.

Loop Density
Loop density is a very important factor in the theoretical designing of various knitted fabrics, as it is the main determinant of loop length and area density. It is especially essential to be able to predict the loop length and area density of a knitted fabric, which is a necessary condition for protective garments in order to avoid mechanical damage during external hazardous factors [1,2].

In general, the loop length of a knitted fabric is determined by mathematical formulas. These formulas are usually simplified and do not require exact values of mechanical forces that act in the loop and between adjacent loops.

The loops of the yarn loops in a knitted fabric are ordered front-to-back, depending on the stitch pattern that defines the knitted fabric. This topological ordering can be analyzed by an algorithm that uses the loop path and a precedence rule to determine which yarn loops are brought to each query location in a fabric grid.

Dyeability
Draw Texturing Yarns are dyed with disperse dyestuffs at high temperatures under elevated pressures. These dyestuffs are not easily accessible and expensive.

The color of these textured yarns is affected by the first heater temperature, the D/Y rate and the texturing speed. They are also affected by the amount of dye that is used and the amount of space dyed filaments.

In addition, the crimp properties of textured yarns are affected by varying heating times during draw-texturing. This is especially the case for microfilament polyester yarns that have been texturized by false twist methods at a lower first heater temperature than during crimp contraction, or by a longer draw ratio, D/Y rate and texturing speed.

During the drawing-texturing of PET partially oriented yarn (POY) on a lab-type Barmag AFK-M texturing machine, the effects of varying the first heater length and temperature on various texturing parameters were investigated. The first heater length and temperature were 2.5 m and 190degC, respectively; the D/Y rate was 650 m/min; and the texturing speed was 1+6+1.