The invention relates to preparation and application of a composite
sizing agent for high-count cotton
yarn sizing and a
desizing method. The preparation and application comprise the following steps: (1) using brewer's grains as a
raw material for preparation of the composite
sizing agent, putting the above materials into a
sodium hydroxide solution, heating at constant temperature of 50-90 DEG C for 30-90 min, centrifuging or carrying out suction
filtration to remove undissolved residue, and using a supernatant to prepare the composite sizing agent for high-count cotton
yarn sizing; and (2) carrying out sizing process of cotton
yarn by the use of a single-yarn sizing
machine, adopting a double soak and press mode with temperature of sizing box being 40-70 DEG C, dying
room temperature being 50-80 DEG C and sizing speed being 10-50 m / min, controlling
permeation and
coating ratio of the size in the yarn according to pressure adjustment, and carrying out coordination control of sizing percentage by sizing agent concentration and pressure. The prepared composite sizing agent is low-cost, has good sizing performance, is suitable for cotton yarn sizing, is easy to desize, contains no hardly degradable substance or substances harmful to the environment, and is clean and
environmentally friendly.