To choose the ideal scraper, consider the following points:
1. Ingredients of scraper: The components contained in the scraper's elastomer are relatively single, but due to the additives incorporated into them, the scraper's performance and quality are different. Polyurethane monomer or derivative Rubber, because its molecular structure is a polar molecular class, therefore, we should avoid weaknesses in screen printing, making it play a unique role.
The most basic reaction of polyurethanes is the reaction of isocyanate groups with polyester. Polyether. Glycol or hydroxy groups of castor oil. Suitable for all kinds of screen printing requirements scrapers are available for sale on the market.
2. The hardness of the scraper: The scraper rubber hardness is mostly in the range of 60-80 degrees. The higher the hardness, the stronger the flexing resistance of the scraper. To maintain stable printing conditions, the scraper's flexing force is not required. Change. The choice of scraper rubber must be free from ink and solvent attack, not affected by mechanical forces, and hardness changes should be small.
Third, the scraper's wear resistance: In order to ensure stable printing conditions, the scraper requires a strong wear resistance, polyurethane Shore hardness of 90 degrees, its strength and wear resistance compared with other rubber products the best.
4. Solvent resistance: Because the squeegee is softened by the ink in the screen printing, it absorbs the acid base in the ink, causing the rubber to swell, causing a false impression in the printing. Therefore, the solvent resistance of the squeegee must be considered.
Reprinted from: China Silk Screen Technology Network