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Polyester

The polyester known as "PET" (polyethylene terephthalate) is used in carpet manufacturing in both spun and filament constructions. After the price of raw materials for many types of carpet rose in the early 2000s, polyester became more competitive. Polyester has good physical properties and is inherently stain-resistant because it is hydrophobic, however oil-based stains can pose a problem for this type of material and it can be prone to soiling. Similar to nylon, colour can be added after production or it can be infused in a molten state (solution dyeing). Polyester has the disadvantage that it tends to crush or mat down easily. It is typically used in mid- to low-priced carpeting.

Another polyester, "PTT" (Polytrimethylene terephthalate), also called Sorona or 3GT (Dupont) or Corterra (Shell), is a variant of PET. Lurgi Zimmer PTT was first patented in 1941, but it was not produced until the 1990s, when Shell Chemicals developed the low-cost method of producing high-quality 1,3 propanediol (PDO), the starting raw material for PTT Corterra Polymers. DuPont subsequently commercialized a biological process for making 1,3-propanediol from corn syrup, imparting significant renewable content on the corresponding Sorona polyester carpet fibers. These carpet fibers have resiliency comparable to nylon.