Processing Of Lyocell Fabric To Achieve The Peach-Skin Effect

Lyocell fiber is characterized by high dry and wet strength, high moisture regain and biodegradability. Though there is a high proportion of a highly oriented, crystalline region within the fiber, the lateral cohesion between the crystallites is weak. When subjected under mechanical stress in swollen state, the fibers tend to produce surface fibrils. This wet fibrillation behavior can be manipulated to create a variety of finished surface and optical effects, such as clean surface and peach skin. Used for high fashion apparel, the peach skin effect can be obtained by a conventional three-stage process, namely, primary fibrillation, enzyme clean and secondary fibrillation."Average value of fibrillation" is developed in this paper to evaluate the fibrillation degree of fabrics which have been processed by different technologies. "Average value of fibrillation" is given by different persons according to the length and density of fibrils on the surface of the treatedfabrics.In this paper, different Lyocell twill fabrics were treated by two different processing methods to get the peach skin effect. Firstly, the fabrics were processed using the conventional three-stage method by a hydraulic jet dyeing machine for lab use. A series of single-factor experiments were conducted to explore a suitable technology for primary fibrillation by analyzing the physical properties and the surface fibrils of the treated fabrics. The main parameters were determined to be as follows: processing temperature 95℃, processing time 90 minutes, sodium hydroxide 2.5g/L and liquor ratio 25:1. In the enzyme clean stage, the acid cellulose "Cellusoft Plus L" were used to remove the fibrils produced on the surface of fabrics during primary fibrillation. The fabric can be imparted a good clean surface when the dosage of the enzyme is 3.0 % (owf) and the processing time is 30minutes.During the secondary fibrillation stage, the fabrics were processed with 10g/L T3S softener and dried by a tumbler. The "average value of fibrillation" of the fabric thus processed is 0.7.On the other hand, the Lyocell fabrics were processed by a lab-made sanding equipment to simulate the sanding processes which are commonly used in factories to get a peach-skin effect on synthetic fabrics. The suitable processing parameters were also determined. The results showed that this sanding method could really lead to a better peach-skin effect on the fabricwith the "average value of fibrillation" being 0.8. Even better effects can be achieved if a two-stage sanding process is adopted.