Protection of lyocell fibres against fibrillation; mechanism for the poor crosslinking performance of reactive dyes on lyocell fibres and the influence of a colourless crosslinking agent as co‐applicant

Abstract

Sandospace R and five multi‐functional reactive dyes have been applied to lyocell fibre, by exhaust methods. A comparison has been made of the number of mmoles of each species covalently bonded to the fibre, with cross‐linking efficiency (NSF values). None of the dyes studied was able to achieve levels of cross‐linking found in non‐fibrillating grades of lyocell, unless unrealistically high levels were applied. Sandospace R readily matched the NSF values found in commercially produced non‐fibrillating fibres. An explanatory mechanism based on differences in size between Sandospace R and the reactive dyes has been proposed. Fitting the experimental NSF data to an Arrhenius model confirmed the increasing gradient of the NSF curves with increasing millimolar concentration of species fixed. The chroma of the agent‐plus‐dye fibre samples remained relatively constant being either at the same level or above that of those fibre samples treated only with dye. Co‐application of Sandospace R with the reactive dyes has achieved levels of cross‐linking found in commercial non‐fibrillating lyocell fibres.

Physical properties and fibrillation tendency of regenerated cellulose fiber dry jet-wet spun from high-molecular weight cotton linter Pulp/NMMO solution

“…Fibrillation in Lyocell fiber originates from its high wet swelling characteristics [12] and weak lateral cohesion between the crystallites [13], which renders it susceptible to mechanical abrasion. In recent times, many researchers have focused their attention on optimizing the production processes to form fibers having lesser fibrillation tendency and good washing stability by using varying methodologies such as inclusion of additives into the dope solution [14], changing the spinning parameters [2,[15][16][17][18], modifying the spinning bath [2,19,20], treating fibers or fabrics with crosslinking agents [11,21,22] to name a few. Notably, Fink et al [2] reviewed the dry jet-wet spinning, precipitation and drying stages of cellulose-NMMO solutions.…”

A New Environmentally-Friendly Method of Dyeing Lyocell/Cotton Blended Fabrics

“…In applications, although the fiber fibrillation characteristic is shown to be advantageous due to the peach-skin effect, it causes problems in the uniformity of color uptake. 2,4,5,[10][11][12][13][14][15][16][17][18][19][20][21] Lenzing has three variants of Tencel-brand lyocell fiber that are non-fibrillating: Tencel A100, Tencel A300, and Tencel LF. 22 Various dyes, such as reactive and direct dyes used in cotton dyeing, are used for dyeing lyocell.…”