HEAT RESISTANCE

High-temperature environments accelerate the aging process, which causes the rubber to harden and crack. Heat also has a seriously damaging effect on the carcass of the belt itself because it damages the adhesion between the cover and the carcass and between the layers of fabric contained in the carcass. This literally causes the belt to crack. This is commonly referred to as “de-lamination.” As the rubber becomes harder and less elastic due to heat exposure, the tensile strength and elongation at break can decrease by up to 80%. This effectively destroys its operational strength and flexibility. At the same time, abrasion resistance can decrease up to 40% or more.

Conveyor belts intended for transporting high-temperature materials, such as clinker, coke, cast iron, glass or other high-heat products, must be made with special rubber compounds that can withstand high temperatures without deteriorating prematurely.

These tapes must ensure:

Temperature resistance: ability to operate with hot materials without compromising structural integrity.
Thermal stability: Retention of mechanical properties despite exposure to heat.
Extended service life: reduction of wear and tear and cracking due to temperature.

The standard ISO 4195 specifies a mtest method for determining the resistance to thermal aging Of rubber conveyor belts. This test simulates conditions of use at elevated temperatures to evaluate changes in the mechanical properties of rubber over time.

ISO 4195 test procedure

Sample preparation
- Rubber specimens are taken from the conveyor belt.
- Sample sizes must meet the specifications of the standard.
Exposure to heat
- The samples are placed in a temperature-controlled oven for a defined period (e.g., 70 °C, 100 °C or 125 °C for 72, 96 or 168 hours, depending on the application).
Measurement of mechanical properties
After thermal aging, the following characteristics are compared with those of the original samples:
- Tensile Strength (MPa)
- Elongation at break (%)
- Shore A hardness
Evaluation of results
- The percentage change in properties from initial values is calculated.

A REFERENCE GUIDE FOR OUR HEAT SHIELDS

HR130: Maximum operating temperature 130° with peaks of 150°

HR150: Maximum operating temperature 150° with peaks of 180°.

HR180: Maximum operating temperature 180° with peaks of 220°

HR220: Maximum operating temperature 220° with peaks of 300°

HR300: Maximum operating temperature 300° with peaks of 500°.