What Is Elastomultiester? The Complete Guide for Indian Textile Buyers
The term "elastomultiester" appears in yarn catalogues, fabric specifications, and export buyer requirements yet many procurement and technical teams in Indian textile mills are still unclear about exactly what it means, how it differs from bicomponent yarn, and whether it is the same as T400 or Lycra T400.
Elastomultiester is the generic fibre category name, defined by international fibre nomenclature standards, for a class of synthetic multifilament yarn that derives its elastic properties from the molecular and physical structure of its polyester polymer system not from an added elastomeric component.
Elastomultiester is defined under EU Textile Fibres Regulation (EU No. 1007/2011) as: "a fibre formed by the interaction of two or more chemically distinct linear macromolecules in two or more distinct phases (of which none exceeds 85%) consisting of esters with at least one functional unit of a diol and terephthalic acid, and which, after suitable treatment, when stretched to one and a half times its original length and released, recovers rapidly and substantially to its original length."
For Indian textile exporters, the regulatory classification matters because EU garment labels must carry the correct fibre composition and elastomultiester must be listed as "elastomultiester," not as polyester, not as bicomponent, not as T400.
PTT chips and PET chips are separately dried to moisture levels below 50 ppm to prevent hydrolytic degradation during melt processing. The drying stage typically uses dehumidifying dryers at 120–140°C for 4–6 hours. Undried chips produce yarns with reduced tenacity, poor elongation uniformity, and increased denier variation.
Each polymer is fed into a separate extruder and melted independently. PTT melts at approximately 225–235°C and PET at 270–290°C. The melt viscosities of the two streams must be carefully matched at the spinneret to ensure stable, uniform filament formation.
The two polymer melts are delivered to a conjugate spinneret a precision-engineered plate that brings both polymers to each spinneret hole simultaneously, in the desired side-by-side arrangement. As the combined melt exits the hole, the two polymer streams bond at their interface and the filament is drawn down by the take-up godet rollers.