Polyester
Used mainly where acid conditions are present or a minimum stretch is desired, polyester is unaffected by common acids and hot bleaching agents, it is not suitable for use with concentrated sulfuric acids, alkaline or at temperatures in excess of 100centigrades or less then -40centigrades , Stretch at rated capacity is approximately 3%(untreated).

Nylon
The most widely used general-purpose synthetic web sling, is unaffected by grease and oil. It has good chemical resistance to aldehyde, ethers, and strong alkalis; but is not suitable for use with acids and bleaching agents or at temperatures in excess of 100centigrades or less then -40centigrades, Stretch at rated capacity is approximately 6-8%. And if wet, maybe the strength will be loss over 10%.

Polypropylene
Polypropylene is little affected by acids or alkalis and suitable for application where the highest resistance to chemicals other than solvents is required. Using temperatures scope is in excess of 80centigrades or less then -40centigrades