Compound Formulation

Compound:

It is a homogeneous mixture of ingredients used in a particular product manufacture such that the properties of most of the ingredients are unchanged in the final product whereby providing a defined set of mechanical properties.

Compounding:

It is the science of selecting and combining elastomers and additives to obtain an intimate mixture that will develop the necessary physical and chemical properties for a finished product.

Rubber compounding is a term covering a wide scope including the art and procedures that are necessary to produce useful products from natural or synthetic elastomers. A competent rubber compounder must be able to use the proper elastomers and additives available to meet the conditions required for the finished product. This requires a thorough understandind of the following:

• Properties of the elastomers available.
• Vulcanizating systems to give the potential properties needed.
• Modifying materials which give the required physical properties and aging resistance.
• Compounds must be able to process properly depending on the processing equipment.
• Commercial compound design.

The average surface area of the carbon black as measured by ‘Nitrogen surface area (NSA)’ divided into 10 arbitrary groups as follows.

Procedure: To the base polymer hardness; add/subtract hardness change for each filler or softener.

%Shrinkage = [0.0205-(100-X) M] x ∆T
where,
X = Rubber Content by volume (include oil, factice etc.), ∆T = Difference between curing temperature & room temperature in ºC
M = Constant depending on filler (Usually, 0.00025 – 0.00030)