Chemical Assessment
Gravimetric measurement of the change in fabric weight during finishing determines the quantity of sizing agent removed from woven flax yarns. This quantitative value, recorded as desizing mass loss, represents the difference in bone-dry mass before and after enzymatic or chemical treating. Mills conduct this test on a sample cut from each production run to verify that subsequent bleaching and dyeing can proceed uniformly.
Process Efficiency
Loom-state flax fabrics contain starches or polyacrylic acids added to the warp yarn to prevent breakage during weaving. Incomplete extraction of these protective polymers creates a barrier that prevents dye liquors from penetrating the flax core, resulting in uneven coloration and stiff fabric handle. Calculating the desizing mass loss involves drying the sample at one hundred and five degrees Celsius, weighing it, executing the desizing procedure, and then drying and weighing the specimen again.
The difference, calculated as a percentage of the original dry weight, must align with the target sizing percentage recorded on the slashing logs. Standard laboratory protocols specify that a mill must run this check immediately after the desizing bath is completed.
Quality Threshold
Woven linen intended for high-grade exports must achieve a minimum value to ensure optimal liquid absorption in the finished fabric. If the desizing mass loss falls below the designated limit of the buyer’s specification, the fabric must undergo a second desizing run. This additional processing increases manufacturing costs and risks weakening the natural flax fibres through extended exposure to heat and chemicals.
The laboratory records the final value in the batch certificate to satisfy the export audit requirements.
