Heat-resistant conveyor belt uses different types of raw rubber, and the product appearance quality are different, and the appearance defects of different rubber types are not same. The following are several varieties of rubber materials we commonly use.
SBR: SBR is the most commonly used rubber material for heat-resistant belts. Compared with the EPR and neoprene rubber, SBR is the most cost-effective. Therefore, many manufacturers generally use it to produce T1 or T2 conveyor belts. The process performance of SBR, such as mixing, calendering, and vulcanization, is pretty easy to master, and the appearance quality is better than that of ethylene propylene and neoprene.
EPDM: Ethylene-propylene rubber is used as the heat-resistant belt cover, which has better heat resistance. Therefore, it is an ideal material for heat-resistant belts. Generally, EPDM rubber can be used for a long time in an environment of 150℃, but EPDM rubber has poor process performance. The cover has poor adhesion, and the surface is often rough and not smooth when the sheet is rolled out of more than 4mm. Therefore, the appearance of the belt has more scars and grooves on the edges than SBR belt. This type of rubber is suitable for T3 conveyor belts.
Neoprene: The heat resistance of Neoprene rubber is not as good as SBR and EPDM, but it has good acid resistance. In the production of chemical industry, acid and heat resistance conveyor belts are required. Due to the low heat resistance requirements(the temperature is below 100℃) and the high acid resistance requirements. We choose the neoprene rubber for some fertilizer industry. The process performance of neoprene rubber is different from that of SBR and EPDM. Due to its high thermal stickiness, it often sticks to the rollers when the film is discharged, and the shrinkage is large when the film is pressed. It is easy to adhere to the hot plate during vulcanization. So bubbles and cracks problem usually happens. Special measures should be taken for the appearance quality to ensure the smooth surface of the belt.
The appearance of the heat-resistant belt produced by different fabric is also different. The nylon belt is easy to has longitudinal wave and scars, while polyester-cotton don’t. Various fabric, including nylon cloth, EP cloth, and polyester-cotton cloth have their own advantages and disadvantages. For different types of fabric, the causes of appearance defects are different.
Polyester-cotton canvas: It has become a history to use pure cotton canvas to produce heat-resistant belts, because the price of pure cotton cloth is too high, and the price of fabrics blended with polyester fibers is much lower, and the heat resistance performance is better than pure cotton cloth. polyester-cotton canvas heat-resistant belts is currently widely used in many companies. The belts have stable dimensions and good appearance, no longitudinal wave, and no crack at the edges. The disadvantage is that the adhesion between the fabric layer is low and the flex resistance is poor.
EP canvas: The warp direction is polyester and the weft direction is nylon. EP canvas is stronger and has better heat resistance than polyester-cotton cloth, especially the adhesive between the layer, so it is more durable than polyester-cotton cloth in harsh environments. However, due to shrinkage during vulcanization, the appearance will also be defective if you don’t pay attention to the production process
Nylon canvas: strong and resistant to flexing, but its heat resistance is not as good as the above two canvases. We use it to produce heat and acid resistant conveyor belts. It has its advantages, but the appearance is easy to longitudinal wave and scars, grooves and cracks.