Method for online detection of polyester staple fiber shrinkage in boiling water

The invention discloses a method for online detection of polyester staple fiber shrinkage in boiling water. Polyester staple fiber samples are selected to reach moisture absorption balance through pre-wetting and wetting processes, at least 6 polyester staple fibers in the samples which reach moisture absorption balance are selected to be put in a neutral or weak alkaline aqueous medium at a specific temperature and are heated until boiling according to a specific heating rate, and the boiling state is kept for 30-40 minutes, so that the samples can fully shrink; and the samples are dried and put at standard atmospheric pressure to be balanced, and the lengths of the shrunk samples are measured and are compared with the lengths before shrinkage to calculate the polyester staple fiber shrinkage in boiling water. By the method for testing, the influences of factors of different types and contents of additives, different polyester staple fiber processing technologies and other factors to the polyester staple fiber shrinkage in boiling water can be eliminated during the polyester staple fiber production process, a measurement result has good repeatability, the evaluation is in accordance with the self characteristics of fibers, and the method has an active guiding meaning to production and is worthy of being widely popularized.