[Polyurethane] Polyurethane foaming – various methods to improve the hardness of rigid foam

During the foaming process, if the hardness of the hard foam is not enough, how to increase the hardness?
01 The lower cost first choice is to add calcium carbonate
Add 20% calcium carbonate, above 500 mesh. This method will not have much impact on performance indicators, mainly because of its low cost.
02 Improve index

Appropriately increase the TDI index, increase the amount of water, and correspondingly reduce the amount of MC, which can also increase the hardness appropriately.
03 Increase the amount of catalyst
Or add other types of catalysts or modifying reagents
There are some catalysts:
① Increase the POP content to within 80%;
② Try adding some modified MDI appropriately;
③ Add some polyester to polyether;
④ Add some rigid foam polyether, and it may be better to choose a polyether with higher functionality;
⑤ Increase the proportion of hard foam expansion and cross-linking agents such as 405 and 403;
⑥ Add trimerization catalyst and increase the proportion of black and white materials.
04 Increase the density of raw materials
That is, when foaming, adjust the foaming ratio appropriately, reduce the foaming ratio, and increase the density.
05 Use a little pore opening agent appropriately
06 Increase foam capacity
07 Adding powder can also increase the hardness