NR 40-45ShA formulation? 1

[ruboma]

HEllo, i´m noob in this site... and my english is very poor XD

I need that somebody send to me a formulation of a NR compound, whith hardness= 40-45 Sha and 14 MPa Tensile strengh ... I need that this compound with a high viscosity
Other compounds of this type ,with low viscosity, originate a lot of dirt in our molds ..and i need a fast aceleration!!!
thank you very much

 

[GrahamBennett]

Ruboma, the formulation that follows should meet ASTM D2000 callout M4AA414 A13 B14. Quantities are given in phr.

SMR10 100.00
N330 1.00 (yes, just 1.00phr)
Whiting 50.00
Process oil 10.00
Zinc oxide 3.50
Stearic acid 1.00
Flectol H (TMQ) 1.00
Sulphur 1.50
MBTS 1.50
TMTD 0.15

Mooney viscosity = 60.
Curing test specimens at 150°C for 20mins should give you the following properties:
Tensile = 17.5MPa, EB = 660%, Shore A = 42°, Compression set (1 day at 70°C) = 11%.

Could the "dirt" be nothing more than mould fouling? This will always occur with ZnO/sulphur systems. The literature shows that most fouling is caused by a build up of zinc sulphide.

Graham Bennett
Tun Abdul Razak Research Centre.

http://www.tarrc.co.uk