Textured synthetic multifilament yarn having alternate grouped S and Z twists and method manufacturing thereof

A method for producing a synthetic multifilament textured yarn from a material multifilament yarn comprising a plurality of individual filaments, by means of a false-twisting apparatus having a false-twisting head comprising

• 1. supplying said material multifilament yarn to a false-twisting apparatus in an over-feeding condition,
• 2. passing the material yarn through a heating zone at a temperature within a range between the softening temperature and melting temperature of the yarn while maintaining said over-feeding condition, the individual filaments of the yarn being softened and partially melted such that the filaments are intermittently fused together to form random compact portions,
• 3. passing said material yarn in a heated condition through the false-twisting head, whereby random bulky portions are formed on the yarn after the yarn passes through the false-twisting head, and
• 4. taking up the resulting treated yarn delivered from the false-twisting head on a take-up device,
• whereby a textured yarn is provided having a plurality of randomly distributed compact portions distributed along the longitudinal axis of the yarn and a plurality of bulky portions, each of said bulky portions consisting of a plurality of crimped individual filaments positioned independently from each other and each bulky portion having an opposite twisted direction of multifilament yarn from the twisted direction of the two adjacent compact portions.