In the screen printing process, the scraper is used to scrape the squeeze ink, the object to be printed on the screen in the tool. The smoothness of the blade directly affects the precision of the printing. In the process of working, the scraper and the screen friction, and with a variety of organic solvents of ink for a long time, so the material of wear resistance, solvent resistance performance challenges. After the use of knife blade wear, can be maintained by grinding the knife edge, extend the life, to ensure that the economy, but also on the aging resistance of the material requirements. A series of polyurethane prepolymer with hardness range from A40 to A90 degree, which can meet the requirements of various working conditions, and the operation window is wide, suitable for manual operation.