A new method of “one blow and two washes” for the analysis of stain categories and content of down raw materials

The down raw materials collected from the slaughterhouses generally adhered with an excessive amount of dust and complex stains which hinder them to be utilized directly for down textiles processing. Water washing is an important core process of down raw material processing for dust removal, decontamination, and sterilization of down fibers. However, there is no standard method to analyze the stain category and content of down raw materials, so it can only rely on traditional experience to wash down, which may cause problems including insufficient or excessive washing, and serious damage to the quality of down fibers. Thus, this study has been specifically designed and developed a method dedicated to categorizing stain types and content of down raw materials. This novel design process is named as “one blow and two washes”, which is composed of three steps to analyze dust content, water-soluble stains, and grease stains in down raw material more accurately. In this experiment, the stain analysis of six different sources of down raw materials was carried out, scanning electron microscope (SEM) and super depth of field 3D microscope system were used to characterize down samples. The results showed that the “one blow and two washes” method could accurately be used to distinguish stain categories of different sources of down raw material with a small average variance value and a coefficient of variation less than 12%, indicating that this experimental method has high reliability and good reproducibility. These research results will provide an important basis for the design of the washing agent dosage and process parameters for raw down, which is expected to achieve the precise washing process of raw down and improve the quality of down.