Page 9 - Shimadzu SMV-301/301RT

Mooney Scorch Test and Measuring Scorch Time Stress Relaxation Test

The system allows stress relaxation measurements in accordance with ISO 289-4 and ASTM D 1646.

The Mooney scorch test is performed to determine the scorch time of rubber compounds. In the scorch test, viscosity decreases before If the rotor is suddenly stopped after the Mooney viscosity test, the stress in the sample attenuates. The stress relaxation test determines the attenuation
increasing as vulcanization progresses. The test measures the time (scorch time) it takes for viscosity to increase from a minimum rate of the stress (torque) as a function of time. The relaxation of stress in rubber materials tends to depend on a combination of viscosity and elasticity,
viscosity value (Vm) to a speci ed increased value (scorch point). JIS standards prescribe a scorch point of 5 M. Model SMV-301 allows where a slower relaxation indicates a higher level of elastic components and a faster relaxation indicates a higher level of viscous components. The Mooney
the user to specify up to 10 arbitrary scorch points, and measure the peak value (Vp), minimum value (Vm), and scorch times. viscosity re ects the molecular weight of unvulcanized rubber, whereas the stress relaxation value is related to the rubber structure, such as the molecular
weight distribution, molecular chains, and gel components. Therefore, it can be used to evaluate the mixing and processing characteristics of rubber.

Vp
● Log-Log Graph
Mooney Viscosity (M) Vm SP1 SP2 Scorch point SP3 Rotor stops MSR＝⊿M/⊿t

Preheat time Scorch point SP1 Scorch point SP2 Time (min) Mooney Viscosity (M) Mooney Viscosity (M) ⊿M (＝Mooney Stress-relaxation Rate)
Scorch time 1 ST1 ⊿t
Scorch time 2 ST2 Time (min)
Scorch time 3 ST3
Time (min)

● Screen for Specifying Scorch Point Measurement Conditions ● Sample printout of Mooney scorch test results ● Sample printout of stress relaxation test results ● Stress Relaxation Test Results (ASTM D 1646)

● Scorch Point Measurement Test Results ● Mooney Viscosity Test Results

Capable of Measuring Differences in Mooney Viscosity Decay Time
(in accordance with ISO 289-3) Mooney Viscosity (M) Test started tx (sec):
Delta Mooney A: MLmax Assuming a 100 % torque value after the rotor stops, tx is the time it takes for the torque
The difference in Mooney viscosity between the rst and last detection time settings MLmin Delta Mooney B to decrease by x % (user speci ed value). Mooney Viscosity (M) X(％)
speci ed is determined. Delta
Mooney Xt (%): Rotor stops
A
Delta Mooney B: Assuming a 100 % torque value after the rotor stops, Xt is the proportional attenuation of
The difference in Mooney viscosity between the minimum value (MLmin) and the maximum torque at a time t seconds after the rotor stops (user-speci ed value).
1 Time (min) Time (sec)
value thereafter (MLmax) is determined. First Mooney viscosity Last Mooney viscosity t(sec)
detection time setting
detection time setting
SMV-301/301RT
8 Mooney Viscometer 9