Solution to Appearance Defects of Heat-resistant Conveyor Belt

Different varieties of raw rubber are used in the heat-resistant covering rubber. The appearance quality and technology of the heat-resistant products are different, and the appearance defects of different kinds of rubber are not necessarily the same. Following are some of our commonly used rubber varieties.

Styrene-butadiene rubber: Styrene-butadiene rubber is the most commonly used heat-resistant compound. Compared with ethylene-propylene rubber and chloroprene rubber, styrene-butadiene rubber sells for more than 21,000 yuan per ton, while ethylene-propylene rubber sells for more than 32,000 yuan per ton and chloroprene rubber sells for more than 32,000 yuan per ton. Therefore, the production enterprises generally use it to produce T1 or T2 conveyor belts. The technological properties of styrene-butadiene rubber, such as mixing, calendering and vulcanization, are better mastered. The appearance quality of styrene-butadiene rubber is better than that of ethylene propylene and chloroprene rubber. The appearance defect was also less than that of EPDM and chloroprene.

Ethylene-propylene rubber: Ethylene-propylene rubber is used as heat-resistant covering rubber, which has better heat resistance. Therefore, it is an ideal material for heat resistance. Ethylene propylene terpolymer can be used for a long time at 150 C in general, and its technological properties are poor. Covering glue has poor stickiness, and the surface is rough and not smooth when the calender is over 4 mm. So the appearance of the tape is more like scar and edge groove than SBR. This kind of glue is suitable for T3 conveyor belt.

Neoprene rubber: Neoprene rubber has less heat resistance than styrene-butadiene rubber and ethylene propylene rubber, but it has good acid resistance. In chemical industry, conveyor belts are required to be acid-and heat-resistant. Because the heat resistance requirement is not high, below 100 C, and the acid resistance requirement is high. Conveyor belts in phosphate fertilizer industry should be both sulfuric acid-resistant and hydrofluoric acid produced in the reaction process. We choose chloroprene as the type T1 tropical resistance. Different from styrene-butadiene rubber and ethylene-propylene rubber, chloroprene rubber has different technological properties. Because of its high thermal viscosity, rolls are often glued to the surface of the tape, the shrinkage of the sheet is large, and it is easy to adhere to the hot plate during vulcanization, resulting in dimples, bright

scars, bubbles and cracks, and repair is not easy to adhere. Special measures should be taken to ensure the smooth surface of the tape and fewer defects.

For example, the T1 heat-resistant and acid-resistant conveyor belt made of nylon canvas is different from the belt made of polyester-cotton canvas and canvas. The belt made of nylon core is prone to longitudinal water ripple and scar, while the belt made of polyester-cotton blend is not prone to water ripple and bright scar. All kinds of materials, including nylon cloth, EP cloth and polyester cotton cloth, have their own advantages and disadvantages. For different kinds of core materials, the causes of appearance defects are different. Three commonly used materials, polyester cotton cloth, nylon cloth and EP cloth, are described separately.

Polyester-cotton canvas: It has become a history to produce tropical resistance with

pure cotton canvas because the price of pure cotton is too high, while blended fabric with polyester fiber is much lower, and its heat resistance is better than pure cotton cloth. Polyester-cotton canvas is widely used in many enterprises to produce tropical resistance. The tape made with it has stable size, good appearance, no longitudinal water ripple, and no edge ditches and cracks. The disadvantage is low interlayer adhesion and poor flexibility.

EP canvas: The canvas with polyester in warp and nylon interwoven in weft is EP canvas. It is stronger and has better heat resistance than polyester cotton cloth, especially rubber and cloth. The interlayer adhesion between cloth and cloth is much higher than polyester cotton cloth, so it is more durable than polyester cotton cloth in harsh environment. However, due to shrinkage during vulcanization, if the process is not paid attention to, the appearance will also produce defects.

Nylon canvas: strong, flexural resistance, but heat resistance is not comparable to the above two canvas, we use it to produce heat and acid-resistant conveyor belt, has its advantages, but the appearance is prone to longitudinal water ripples and scars, ditches and cracks.