Лако-красочные материалы — производство

High reinforcing capability, fine carbon blacks, tire tread blacks (particle size: 18­28 nm)

4.7.1.2

Semi-Active Blacks

Lower reinforcing capability, carcass blacks (particle size: 40-60 nm).

4.7.1.3

Inactive Blacks

Negligible reinforcing capability, high filling rates (particle size: >60 nm). Though the preceding typology is still widely respected, the internationally recognized ASTM designations are those generally used (Table 4.5). The first character in the nomen­clature system for rubber-grade carbon blacks is a letter indicating the effect of the carbon black on the cure rate ofa typical rubber compound containing the black. The letter “N” is used to indicate a normal curing rate of typical furnace blacks that have received no special modification to alter their influence on the rate of cure of rubber. The letter “S” is used for channel blacks or for furnace blacks that have been modified, usually by oxidative methods, to effectively reduce the curing rate of rubber. Channel blacks characteristically impart a slower rate of cure to rubber compounds. Thus, the letter “S” designates a slow cure rate. Blacks may vary considerably in “curing rate” within each of the two letter classifications. The second character in the system is a 3-digit number the first digit of which designates the average surface area of the carbon black as measured by nitrogen surface area. The surface area range of the carbon blacks has been divided into six arbitrary groups, and each has been assigned a digit to describe that group.

The N 300 series is characterized by a wide variety of rubber blacks, covering about 10 different types. As mentioned above, fine-particle active blacks are used for rubber components that need to withstand significant levels of mechanical stress, e. g. tire treads. Semi-active blacks, on the other hand, are used in the tire carcass but also in technical rubber components, from screen and door seals to floor mats. Tires also contain other special carbon blacks, for instance, so-called adhesion blacks for improving radial steel belt adhesion, conductive blacks or inactive blacks for higher filler load rates [4.26].

4.7.2