CORTERRA* is the trade name for polytrimethylene terephthalate (PTT), a thermoplastic that can be spun into both fibers and yarns and has extensive applications in carpeting, textiles and apparel, engineering thermoplastics, non-wovens, films and monofilaments.

CORTERRA Polymers combines the best properties of nylon and polyester. Whether used in carpet, apparel, home furnishings or automotive fabrics, CORTERRA Fibers look better longer.

Compared with other synthetic fibers like nylon and acrylic, CORTERRA Fibers feel softer, dye easier, retain vibrant colors longer, stretch and recover better. More important, CORTERRA Fibers resist staining, clean easily and dry quickly.

PTT was first patented in 1941, but it was not until the 1990s, when Shell Chemicals developed the low-cost method of producing high-quality (PDO)1,3-propanediol, the starting raw material for PTT, that commercial production of CORTERRA Polymers was possible.

Polymer description
Shell Chemicals has introduced CORTERRA* Polymers, a revolutionary product line. CORTERRA Polymer is an aromatic polyester known generically as PTT, (polytrimethylene terephthalate). PTT is produced by the poly-condensation reaction of PTA (purified terephthalic acid) and PDO (1,3 propanediol) and has unique properties as compared to the other aromatic polyesters, PET (polyethylene terephthalate) and PBT (polybutylene terephthalate).

The unique properties of PTT have been known for many years but the polymer has not been commercially available because of the high cost of production of the PDO raw material. Extensive research effort by Shell Chemicals has resulted in a cost-effective process to manufacture PDO. With this breakthrough in processing technology for PDO, CORTERRA Polymers are now commercially available for use in carpet fiber, textile fiber, monofilament, film, non-woven fabric, and engineering thermoplastic applications.

• soft
• resistant to stretching
• quick drying
• wrinkle resistant
• able to retain heat-set pleats and creases
• easily washed

Yarns made with CORTERRA Polymers can bring together the most appealing advantages, all in a single fiber. Fabrics made from CORTERRA Fibers not only offer easy-care and stretch, but a combination of features that include inherent stain resistance, lasting durability for longer wear, remarkable softness, beautiful fluid drape and rich brilliant colors. There also are benefits for textile manufacturers: CORTERRA Fibers dye well at low temperatures, blend well with other fibers, and are less expensive and much easier to work with than spandex

Fabrics made with CORTERRA Fibers have great appeal in the fast-growing stretch market. Unlike other stretch fabrics, these easy-care fabrics offer a combination of features that include the softness of nylon, beautiful drape and brilliant colors.

• POY yarns
• flat yarn
• textured yarn
• high tenacity
• monofilament
• staple fibers
• tow
• spun yarns

What is CORTERRA?

CORTERRA* is the trade name for polytrimethylene terephthalate (PTT), a thermoplastic that can be spun into both fibers and yarns. PTT belongs to a class of polymers called aromatic polyesters. However, CORTERRA Polymer is a unique product in that it behaves very differently than other polyesters.

In both carpet and textile markets, CORTERRA Polymers combine the chemical resistance characteristics that you can get from a polyester with the elastic recovery and resilience of nylon. CORTERRA Polymers also offer inherent stain resistance, are continuously printable and dyeable without specialty chemicals in a full color range, have good colorfastness against UV light, ozone and NOx, provide low water absorption and low electrostatic generation, and have the potential to be recycled, pending development of post-consumer recycling programs.

Many of these same properties make CORTERRA Polymers good candidates for conversion into film, non-woven fabric and monofilament. For engineering thermoplastic applications, CORTERRA Polymers can be compounded to provide performance properties and processing characteristics that are similar to polybutylene terephthalate (PBT).

How, when, and by whom were CORTERRA Polymers or PTT discovered?

PTT was first patented in 1941 by Britons John Rex Whinfield and James Tennant Dickson, two scientists with Calico Printing Ink, who were conducting a basic research program on polyesters.

Although the advantages of PTT have been known since the 1940s, PTT was never commercialized due to the nonavailability of a low cost source of the starting raw material, propanediol (PDO). Shell Chemicals was the first company to manufacture PDO, starting in the 1960s. In the early 1990s, Shell Chemicals developed an innovative means of producing PDO economically through continuous ethylene oxide (EO) hydroformylation

How does CORTERRA compare with other fibers?

CORTERRA combines the best properties of nylon and polyester. Whether used in carpet, garments, home furnishings or automotive fabrics, CORTERRA Fibers look better longer. Compared with other synthetic fibers like nylon and acrylic, CORTERRA Fibers feel softer, dye easier, retain vibrant colors longer, stretch and recover better. More important, CORTERRA Fibers resist staining, clean easily and dry quickly

Why is CORTERRA "the fiber of the future"?

It is the first significant new material in the textile and carpet industry for some time. It provides manufacturers with a wider range of options for new products than they have now. As a stain- and static-resistant material, for example, CORTERRA PTT has those properties built in. These properties are not the result of additives. In carpeting, CORTERRA Fibers feel like wool and perform equal to or better than nylon 6,6. But they hold dyes much better, and that means manufacturers will have a wider color spectrum to chose from and produce carpets with a lasting, visual beauty. In apparel, CORTERRA Fibers offer performance that is equal to or better than nylon 6,6 and PET, including comfort fit due to superior stretch and recovery, excellent drape and softness and easy care due to stain resistance and a choice of care procedures.

The target of PTT (and PBT) is not to take market share for PA or PP but to change the consumers perception of polyester in general, to regain market share partially lost by polyesters previously poor image. Once textured:

• PTT will have slightly more power stretch and recovery than PBT and more than PA 66, PA 6 and PES
• PBT will have the best soft hand of all, as PBT will be close to PES
• both can be easily dyed at 100°C and can be mixed with other fibers. They will offer stain resistance, chlorine resistance and a good resilience

Comparison

Type	PTT	Conventional Polyester	PBT	Nylon 66
Tensile Strength (cN/dtex)	3.4 – 3.7	3.7– 4.4	3.5	4.1 – 4.5
Elongation at break (%)	36 – 42	30 – 38	38	32 – 44
Initial Young’s modulus (cN/dtex)	23	97	23	31
Tensile recovery from 20% elongation (%)	88	29	40	62
Specific gravity	1.34	1.38	1.34	1.14
Moisture regain (%)	0.4	0.4	0.4	4.5
Boil shrinkage (%)	14	7	15	13
Melting point (°C)	230	254	230	253
Glass transition point (°C)	51	69	25	76
Weathering resistance	Negligible loss of strength	Negligible loss of strength	Negligible loss of strength	Moderate loss of strength, yellowing under some conditions
Yellowing resistance (w/exposure to NOX-BHT, vanillin, and dry heat)	Negligible yellowing	Negligible yellowing	Negligible yellowing	Yellowing under some conditions

Technical Info

Ø        PTT filament yarns at similar dtex per filament are softer than PET – they are as soft as PA

Ø        Softness comparison (+2 best/ -2 worst):
PTT               +2
PBT               +1
PET               –1
PA 6/PA 6.6  +1
EA                 -2

Ø        A PTT 3 dtex per filament is as soft as a PET with 2 dpf

Ø        Fine filaments are less resilient, a compromise between stretch and softness is necessary.