Heat treatment discoloration Most adhesive prints must be heat treated.Some inks are heat resistant, and there will be a significant color difference after treatment, too -especially when mixed with a thick plate of thermal ink for printing. Therefore, it is necessary to perform a heat resistance test on the color. The test method is: 37% white adhesive + 60% transparent adhesive + 3% colour, after natural drying, heat treatment at 180 ° C for 30 seconds, the highest grade is 5, and the naked eye can not distinguish it before and after heat treatment is 5th grade.
