Tdi- Ppg Prepolymers

Properties
TDI-PPG ether prepolymers are designed to offer a reasonable level of physical properties at a price advantage over TDIa PTMEG systems.


They offer:

a reasonable level of physical properties
low cost
good hydrolysis resistance
ease of use
low viscosity

Typical Applications

Dunnage
Non-dynamic roller coverings (e.g. conveyor rollers for the steel industry)
Scraper blades (e.g. snow plough blades)
Wheels (low load)
Processing can be by hand or by dispensing machine

Hand Processing

Melt prepolymer at 50-60A C for 12-24 hours
Heat the prepolymer and curative to the recommended temperature
Add pigments and Antifoam, as applicable,whilst mixing
It is recommended that air be removed from the prepolymer under vacuum prior to addition of the curative
Add the curative and thoroughly mix ensuring that no unmixed material is left on the
container sides (if necessary the mixcan be transferred to a second clean container and mixed again)
Remove air under vacuum
Cast into moulds, preheated to the recommended temperature
Cure as recommended

Processing Considerations

Avoid prolonged storage of prepolymers at elevated temperatures.
This will result in low hardness and lower properties of the cured materialAvoid moisture contamination of all materials
Part used containers should be flushed with dry nitrogen and resealed immediately after use
The development of cure is longer than for PTMEG systems.
Rapid temperature changes during the early stage of cure should be avoided