Dump temperature
Dump temperature
(OP)
I have a bunch of doubts, it will be helpful if anyone can help me with this.
1.On which basis we are fixing the kneader's dump temperature for vairous rubbers in kneader mixing?
2.What are all the important parameters in setting the dump temperature?
3.Are there any different rheo attributes for kneader mixing and open mixing?
4.Will TS2 and TC90 be affected when the ML value of the compound changes?
1.On which basis we are fixing the kneader's dump temperature for vairous rubbers in kneader mixing?
2.What are all the important parameters in setting the dump temperature?
3.Are there any different rheo attributes for kneader mixing and open mixing?
4.Will TS2 and TC90 be affected when the ML value of the compound changes?





RE: Dump temperature
The type of rubber (and formulation) will determine your dump temperatures. CR rubbers have low dump temperatures, very soft EPDM just don't cause enough friction to go high.
2. I assume you should mix as economically as possible. Shortest time, high energy input to have a good dispersion.
If your dispersion is not good enough, you need to change your mixing procedure.
3. viscosity might differ a bit, open mixing takes far longer.
4. yes, but the question too vague or broad to give a usefull answer.
RE: Dump temperature
I don't know how to decrease the ML in kneader mixing.
RE: Dump temperature
RE: Dump temperature
For compounds containing NR, SBR and BR, you can mix masterbatches (i.e. no curatives) up to 170°C in an internal mixer (Banbury, Intermix). Once mixed, dump and batch off in sheets or pellets and cool down. Leave for 24-48hrs before mixing the final stage when you add the curatives. Final stage mix temperature must never exceed 100-105°C and you must cool the batch down very quickly once it has been dumped in order to prevent any pre-curing.
As Metten said, polymers containing chlorine (Neoprene, Chlorobutyl, etc) or bromine (Bromobutyl) must be mixed to lower dump temperatures (around 130-135°C for masterbatch stage).
forumtowers.com
RE: Dump temperature
RE: Dump temperature
RE: Dump temperature
NR and SBR have much higher molecular weights than most other elastomers so mixing to high temperatures helps break down the polymer chains to make downstream processing that much easier.
forumtowers.com
RE: Dump temperature