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A-B
ACCELERATORS
Chemicals which are added to rubbers to accelerate the rate of vulcanisation. Rubber without accelerators takes twenty or thirty times longer to cure.
ACID ACCEPTORS
Mostly used in Neoprenes to absorb the acid produced by the chemical reactions which take place during curing. Acid acceptors are usually metal oxides.
ACTIVATORS
Chemicals which are added to rubbers to activate curing.
BACKRINDING
A "breaking up" of the rubber normally observed around tool split lines. It results from the rubber shrinking during cure and tearing away at points where the moulding is held.
BANBURY MIXER
An internal mixer commonly used in the rubber industry. It consists of two shaped rotors which turn inside a sealed chamber.
BLEEDING
The exudation of droplets of excess plasticiser onto the surface of the rubber. This happens when rubbers contain unsuitable levels of plasticisers which are not fully compatible.
BLOOM
A white or light coloured crystalline deposit on the surface of the rubber. Many chemicals added to rubber have a limited solubility. If they are present in a cured rubber at levels higher than their solubility, they crystallise out onto the surface.
BUILDING TACK
Term used to describe the ability of a rubber to stick to itself in the uncured state, so allowing pre-building of the material before curing.
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