Evaluation of Polyvinyl Alcohol Size Pick up on Flax Fibers
Optimal PVA size pick-up on flax warps ranges from 8.0 to 9.0 percent dry weight, balancing yarn friction resistance with hot-water desizing washability.
Dry Solids Concentration
Solids Quantification
Total mass per unit volume of slurry establishes dry solids concentration within steeping vats during linen production in Chinese mills, where flax fibre extraction relies on precise bath density. Operators measure the resulting percentage via oven drying small slurry samples drawn from wet processing lines. Mass differences before and after moisture removal yield the exact ratio of suspended plant matter to liquid carriers.
Moisture Threshold
Excess moisture degrades alkali penetration during chemical retting stages, so bath managers track dry solids concentration closely to prevent fibre weakening. High readings signal excessive plant debris accumulation that clogs filtration screens, while low readings indicate over-diluted baths that leave pectin compounds intact on flax strands. Technicians adjust incoming water valves whenever density measurements drift outside specified limits, maintaining uniform chemical activity across each production shift.
Acceptance Threshold
Mill export certificates record dry solids concentration values alongside breaking tenacity ratings for final buyer review, verifying that processed flax meets international commercial standards. Commercial contracts establish strict lower and upper limits for residual moisture and suspended matter in shipped lots, protecting spinners from paying for trapped water weight. Buyers reject deliveries failing these density specifications because excess water disrupts subsequent carding and spinning machinery performance.