In the Coating Center, 80% is hot vulcanised and 20% cold bonded. Cold bonding involves establishing a chemical bond between the vulcanised rubber and the shell. The shell is degreased and metal blasted in a fully automatic blasting chamber, and then rubber is transferred to the shell via a bonding process. This finished rubber usually has a smooth surface and is not processed further. 'Smooth' cold bonding shells are used for driving all types of belts except several modular belts.
Hot vulcanized shells are also degreased and blasted on the inner and outer surfaces. They are then subjected to a special 'primer finish'. An extruder coats the product with uncured rubber, and following that, an autoclave vulcanises the tubes at 150°C and a pressure of 5 bar. The shells are then subjected to an abrading process, and can be ground smooth, spherically, crowned or cylindrically. It is also possible to grind slots or profiles into the surface for driving full PU material or modular belts, in fact just as the customer desires. A unique CNC machine designed exclusively by Interroll is used for the grinding and profiling process.
Coating Center standard rubbers:
- NBR Black, 65Shore A
- NBR White, 70Shore A, FDA + EC1935
- NBR Blue, 70Shore A, FDA + EC1935
- Other qualities, colours and hardnesses can be supplied in accordance with customer requirements and volumes