Introduction to carcass materials for acid and alkali resistant conveyor belts

Acid and alkali resistant fabric conveyor belt is a conveyor belt that is resistant to acid and alkali media corrosion and is mainly suitable for continuous production in acid and alkali media environments. It is resistant to corrosion by acid and alkali media, has good groove formation, high production efficiency, and low relative cost, which cannot be replaced by general-purpose fabric conveyor belts. Acid and alkali-resistant fabric conveyor belts are widely used in heavy industries such as the chemical industry, where acid and alkali media are used.

Carcass material

The carcass is made of polyamide or polyester fibers with high tenacity, high joint strength, and good impact resistance.

Polyamide fibers, known as nylon, have basic properties are as follows.

(1) high strength, good impact resistance. 

(2) high elasticity, good fatigue resistance, rebound rate of 98% ~ 100%, resistance to multiple deformations.

(3) Heat resistance is poor, the shrinkage strength of the fiber decreases when the temperature rises. Heating at 150°C for one hour, strength retention 69%.

(4) Good abrasion resistance, better than other fibers, 4 times better than polyester. 

(5) Poor light resistance, as the amide bonds in the macromolecule are susceptible to breakage by light, resulting in a loss of high polymers.

Polyester fibers

Polyester fiber, basic properties are as follows. 

(1) Slightly lower in strength than nylon. The impact strength is four times higher than that of polyamide fibers. 

(2) High elasticity, with the resilience of 100%, optimum wrinkle resistance, and good fatigue resistance. 

(3) Heat resistance and thermal stability, polyester fibers have good heat resistance and thermal stability, with only a 15 % to 30 % loss of strength when heated in hot air at 150°C for 16 hours and a 50 % loss of strength when heated for 1,000 hours, whereas ordinary fibers will disintegrate after 200 to 300 hours under these conditions. 

(4) Abrasion resistance, second only to cotton fibers.

(5) Density and moisture-return rate. The density is higher than that of other synthetic fibers, and the moisture regaining rate is extremely low because polyester fibers have no hydrophilic groups in the macromolecular chain and only a small moisture absorption capacity in the molecular end groups.

(6) Chemical stability, polyester is resistant to acids but not alkalis and can degrade under certain temperature conditions when exposed to ammonia compounds.

(7) Lightfastness, polyester has a strong retention rate of 30% to 40% after sunlight resistance.

Therefore, for different environments and different requirements, two types of carcass structures are used: polyamide and polyester.

The surface of the polyamide and polyester fibers is treated with latex, which serves to achieve good adhesion with the core rubber between the canvas layers.

This latex has excellent adhesion to the rubber, a high degree of adhesion, and its physical and chemical properties are relatively stable. As a result, the rubber is firmly bonded to the core layer, which ensures a long service life, impact resistance, and high joint strength of the conveyor belt.