Pretreatment of Knit Fabric: Singeing, Desizing, Scouring and Bleaching
Pretreatment decides absorbency, whiteness and dye uniformity, and errors here cannot be corrected later in the process.
The following sections cover the definition, the specification values, production control, testing and commercial impact.
Singeing and desizing
Singeing removes surface fibres on wovens, and desizing removes size applied during weaving preparation.
It rarely appears on a packaging claim, yet it shapes how the garment feels in the first hour of wear.
Scouring and its purpose
Scouring removes oils, waxes and pectins so that water and dye can penetrate the fibre evenly.
Specify the value on the finished fabric rather than on greige, because finishing changes almost every parameter measured.
- Request test reports on production fabric, not on development samples
- Verify the sampling plan and the number of specimens
- Store reports with roll or lot identification for traceability
Bleaching considerations
Peroxide bleaching raises whiteness but can damage cellulose if the process is not tightly controlled.
Consider the interaction with other processes, because improving one stage on its own often shifts the problem elsewhere.
Knits need gentle handling
Stretch knits are usually processed in rope form, so tension and speed control protect the loop structure.
Compare results before and after the intended care regime, since performance often changes after the first wash.
- Agree tolerances in writing before the first sample is made
- Define the measurement condition and the direction measured
- Review the limit each season against real performance data
Control measurements
Check absorbency, residual peroxide, pH and whiteness before the fabric moves to dyeing.
Where volumes are modest, consider consolidating colours or constructions to reach an economical run length.
Summary
The technical content is straightforward. The discipline lies in writing it down, testing it on production fabric and repeating the result on the next order.
