Applications

The rheological, mechanical and structural properties of the so called chain-extended polycondensates are essentially the same to those of products produced by SSP. No branching takes place and the same MW distribution is obtained. The viscosity increase obtained depends on the amount of chain extender added and the processing conditions. A slight decrease of the melting point of the polycondensate may be observed (0 - 3 ºC), depending on the amount of chain extender used. Thus applications that are attainable for the SSP products are also achieved with chain-extended resins.
 

The main advantages of chain extension compared with a post-condensation process are:

• lower system costs (less capital and labor costs),
• faster reaction,
• more flexibility in production and product grades,
• no need for investments (in SSP equipment).  

Compared with existing chain extenders our system clearly excells in linearity and effectiveness. Typically, the relative viscosity of PET in metacresol (1 wt%, 25 ºC) is increased from 1.6 to 1.9 with a stoichiometric amount of ALLINCO CBC (ca. 0.7 wt%) in a single screw extruder at 300 ºC. In a blank experiment without chain extender, this relative viscosity drops to 1.5. Similarly, the relative viscosity of PA 6 is increased from 2.5 to 3.4 with a stoichiometric amount of ALLINCO CBC at 260 ºC.
 

The most important application areas for chain extenders are:

• PET and PA industrial yarns/fibres, monofilaments and strapping
• PET and PA recycling
• PET custom containers/carbonated soft drinks bottles and films
• PA, PET and PBT engineering plastics for E&E and automotive