SWICOFIL - Yarn and fiber expert.


Dyeability of yarn and fibers.
As a result of the economic pressure some of the customers have adopted a new habit not to carry out fabric dye performance tests before going into mass production. A few incidents are forcing us to draw your and all customers attention to the technical importance of:


Every customer - especially the ones in weaving - has the duty to carry out preliminary tests always before starting a production. This is a standing duty of diligence!

Industrial High Tenacity Yarns

Generally speaking all our high tenacity polyamide 6.6 and polyester yarns have not been developped for plain dyeing processes. High tenacity yarns have a different molecular structure compared to textile yarns and consequently different physical and chemical properties.

Therefore new customers must be informed that dyeing behaviour of any high tenacity yarn is critical.

Textile Yarns

Generally speaking all our 1a grade textile polyamide 6.6 and polyester yarns and fibres are good for plain dyeing processes. Special attention shall be brought to Polyamide 6.6 brigh trilobal.
Fabrics made from multilobal yarns are more prone to show barré effects than fabrics made from yarns with a round cross-section. This is due to:
  • the special extruding technique
  • the cross-section itself; the light reflection may be varying and therefore the    finished fabric may appear to have a barré effect. This is extremely critical in unpigmented, bright yarns.

Recommendations for the use of flat and textured multilobal yarns (trilobal)
Multilobal yarns are suitable without restriction for prints and multicoloured applications.The use in woven and warp knitted plain fabrics may be a certain risk. Special care and test-dyeings are necessary for warp and weft material. For particular vulnerable shades we ask all customers to send us a test sample prior to start commercial production. Otherwise we cannot accept any responsibility for barré effects.

Dyeing instructions
  1. Plain fabrics should be piece-dyed. For yarn-dyeing it is recommended that a careful sorting on hanks or cones is carried out.
  2. For dyeing we recommend specially made acid dyestuffs for polyamide. Use proven levelling agents such as Lyogen P and Sandogen NH, Sandogen CN (Sandoz), Univadin PA or Univadin PS (Ciba), Teban ES (Dr. Th. Boehme), Levegal FTS (Bayer). Also reliable are procedures with acid donors like Sandacid V (Sandoz) or Eulysin products (BASF).
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