Desizing agent for production process in pretreatment of printing and dyeing and preparation method thereof

The invention relates to a desizing agent for a production process in pretreatment of printing and dyeing and a preparation method thereof. The desizing agent comprises the following components by weight percent: 25% to 35% of alkali metal hydroxide, 5% to 10% of alkali metal phosphate, 5% to 10% of alkali metal silicate, 2% to 6% of alkaline-resistant penetrant and the balance of water. The preparation method of the desizing agent comprises the steps of: (1) adding the alkali metal phosphate and the alkali metal silicate to the water according to a formula; stirring at the temperature of 35 DEG C to 45 DEG C; then adding the alkali metal hydroxide; keeping the temperature and stirring for 1.5 to 2.5 hours; (2) adding the alkaline-resistant penetrant to the solution obtained in the step (1); stirring for 1.5 to 2.5 hours at the temperature of 60 DEG C to 70 DEG C; and cooling to prepare the desizing agent. The desizing agent has the advantages of complete desizing, small utilization quantity (which is only arounf 15% of the utilization quantity of traditional liquid caustic soda), convenient cleaning, low wastewater yield and small pollution, and reduces the printing and dyeing cost. The preparation method has the advantages of simple preparation technology, easy acquirement of raw material and low production cost.