Different classes in PTT Fibre

CORTERRA Polymer 200

CORTERRA 200 can be used by itself, as the base polymer for compounds, or as a polymer modifier for many engineering thermoplastic applications. Compounded engineering resins based on CORTERRA PTT polymer provide physical properties that are equivalent to or better than those of similar PBT compounds. Extrusion and injection molding conditions, and processing characteristics are very similar to those established for PBT. PTT compounds generally exhibit higher tensile strength, flexural modulus and heat deflection temperatures but with slightly lower impact strength than the PBT counterparts.

CORTERRA Polymer 9200

CORTERRA 9200 is a clear, PTT homopolymer. The polymer properties which provide resilience, elastic recovery, high bulk, soft hand, inherent stain resistance, and ease of dyeing, make it well-suited for carpet and textile fibers. CORTERRA 9200 is used when a very bright and shiny luster is desired in the end product.

CORTERRA Polymer 9240

CORTERRA 9240 is a semi-dull, PTT homopolymer. The polymer properties which provide resilience, elastic recovery, high bulk, soft hand, inherent stain resistance, and ease of dyeing, make it well-suited for carpet and textile fibers. CORTERRA 9240 has TiO2 added as a dulling agent and is used when a bright or shiny luster is not desired in the end product.

Polymer Production

There are two routes to synthesis PTT: the transesterifi-cation of dimethylterephthalate (DMT) with PDO and the esterification route starting with terephthalic acid (PTA) and PDO - these are similar to PET synthesis. With the exception of the process temperature and catalysts, the synthesis of PTT follows more or less the same chemical rules as the PET process. As a consequence, it is possible, in general, to convert existing PET production facilities to produce PTT. The easiest way is to use an existing redundant PET batch-plant. In any case, it is necessary to have a separate PDO rectification unit available. Depending on the design of the polycondensation reactor, it is possible to produce PTT of an intrinsic viscosity, in a range of 0.65-0.85dl/g. More complicated, but still possible, is the conversion of a continuous polycondensation plant from PET to PTT. 

If the molecular weight of the PTT out of the melt-phase polycondensation is too low it is also possible to increase it afterwards by solid-state polycondensation (SSP). Technology and equipment for the SSP of PTT are again very similar to those of PET solid-state polycondensation processing. Finally, the best but most expensive solution is to build a polycondensation line that is tailor made for PTT. There are reliable equipment and matured melt-phase polycondensation technologies from leading engineering companies, including Zimmer AG and EMS-Inventa- Fischer to produce PTT, to high quality, on continuous lines. To reach the desired intrinsic viscosity in the melt-phase polycondensation, the finisher equipment, as used in PBT production, is useful for PTT. 

Origin for PTT Production

The production of PDO is key to the manufacture of PTT. Both process economy and PTT-polymer quality are strongly dependent on PDO purity. Especially aldehydes and ketones which are side products of the PDO and PTT production should be reduced to a very low level. However, this demand for PDO purity is similar to that for fibre-grade ethylene glycol, as it is used for PET production. Larger industrial facilities producing PDO, including DuPont use the acrolein process from Degussa and Shell, based on ethylene oxide, carbon monoxide and hydrogen. Recently, DuPont has announced the start up of PDO production, based on a biochemical route, using cornstarch as feed stock. DuPont has applied for a patent for this process. Because of high development activities in the field of PTT from some Japanese companies, such as ASAHI, TORAY and TEIJIN one can assume that PDO might soon available from the Japanese chemical industry. Finally, there are two main factors responsible for the velocity of further industrialization of PTT: highly effective polymer production and processing technology, and the price of PDO.