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4.6 Multi Filament Sewing Thread
Filaments often bonded with synthetic fibre copolymer that bonds the individual filaments and yarns together to give optimum sewing performance.
4.7 Intermingled thread
Continuos filament core surrounded by entangled filaments by an air jet. The core filaments contribute to tensile strength and the entangled surface filament increases the fullness and reduces the yarn friction textured yarns
4.7.1 False Twist Textured Thread
Textured threads are very soft and extensible; these threads are ideal knitted goods under wears
4.7.2 Air Jet Textured Continuos Filament Yarns
It provides discontinuous thread in the surface, which helps to reduce the danger of thread fusion at high sewing speeds .the soft handle fulfill the soft seam requirement.
4.8 Core-spun Sewing Threads
Extra ordinary strength and abrasion resistance of the polyester filament are provided strong and firm seams. Superior heat insulation of cotton cover makes seam totally a heat proof and excellent elastic recovery with no thread breakage at point of stress. Lubricant is retained well in the surface of the cotton to provide superior cooling to prevent thread burnout at the needle eye.
5.0 Treatments for Sewing Threads
5.1 Heat setting/Twist deadening
Setting of twist is made effective by steaming the yarns in an auto calve with steam pressure of 0.6 kg/cm2 for 30-60 minute. Temperature of the steam has to be maintained with 100-105 Centigrade. The steaming time is decided on the basis of twist level in the doubled yarn. The heat-setting leads to stabilization and equalization of the elongation properties of the thread and it prevent the snarling. Polyester and Nylon threads required high pressure steaming and the industrial sewing threads needed low pressure steaming.
5.2 Dyeing
High color fastness and precise shade matching are the key factor requirements for sewing threads normally to get uniformity cross wound packages with high pressure equipments used.
5.3 Hot Stretching
Hot stretching is a process of heating the thread to pre determined and controlled temperature in the range of 180-240 Centigrade with tension and length control. Heat setting operation causes a decrease in the modulus and increase in the extensibility of the thread. Consequently when high modulus thread requires subsequent stretches. This hot stretching improves the thermal stability and reduces the extensibility. The sewing thread length improved 4. -6%. The specific tenacity improved to 3-5%. This helps to get improvement in dyeing and kink free sewing thread.
5.4 Lubrication
Gliding and cooling effect on the needle could be done with effective lubricants good lubricant must not clog on the needle eye or causes stain. The lubricant must allow the thread to unwind evenly from the package. The friction between the abrading surfaces should be minimized with lubrications. Inexpensive lubricants will be preferred.
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