Residual scorch

The scorch behaviour of compounds is generally studied with the help of a mooney viscometer. The test is usually conducted at temperatures encountered during processing of the rubber stock. Typically this is in the temperature range of 250°F to 275°F. From a chart of mooney units vs test time, the time required for the 

The most common method of measurement is to run the compound in the mooney viscometer until the viscosity shows a 5 point rise above the minimum. The viscosity of the compounded rubber at the processing temperatures can also be obtained from the minimum of the curve. The values normally taken from the cure curve are  

MV = Minimum viscosity T5 = Time to scorch at MV + 5 units T35 = Time to cure at MV + 35 units ATL = Cure index = T35 - T5 

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The volume of the dispersion was reduced by careful heating until the salt was just dry. "Just dry" as used herein means that all of the liquid had been boiled off, but the solid residue had not been "baked" or scorched. 

Dry heat in air causes less damage to wool than wet heat does [13,267,268]. Above 140°C, yellowing or scorching occurs lanthionine, lysinoalanine, and isopeptide cross-links are formed, and solubility in urea-bisulfite solution decreases. Cysteic acid residues are formed... 

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