The latex rubber stability test machine / apparatus tests the mechanical stability of concentrated natural and synthetic latex rubber when subjected to high speed mechanical stirring or mechanical shear.
Stirring is applied to the latex rubber at a constant of 14,000 rpm until the end point, or latex instability is reached.
The approach to the end point is usually indicated by a drop in meniscus of the latex, loss of turbulence and a change in the sound of stirring action.
The end point is determined by the first appearance of small pieces of coagulated rubber.
This end point is confirmed by the presence of an increased amount of coagulated rubber after 15 seconds additional rotation.
The end point in this case is the presence of approximately 1% of coagulum based on total solids.
The mechanical stability value for a latex is expressed as the number of seconds elapsed from the start of the test to the end point.
Stirring is applied to the latex rubber at a constant 14,000 rpm for a time between 1 min and 30 min, as agreed between the interested parties, but of duration such that the latex does not increase in temperature to more than 60 °C and does not rise to a height exceeding 100 mm in the container.
After stirring, the coagulum formed is separated from the liquid and dried and weighed.
The mechanical stability of the synthetic latex is expressed as the percentage by mass of coagulum formed, relative to the mass or total solids of the test portion of latex.
The greater the percentage of coagulum formed, the poorer the mechanical stability.
BS ISO 35 : 2006
Natural rubber latex concentrate. Determination of mechanical stability
BS ISO 2006-1 : 2009
Rubber latex, synthetic. Determination of mechanical stability. High-speed method
ASTM Designation D1076 - 15
Standard Specification for Rubber - Concentrated, Ammonia Preserved, Creamed and Centrifuged Natural Latex
ASTM Designation D1417 - 16
Standard Test Methods for Rubber Latices - Synthetic
For in-house and non standards testing the Klaxon latex test machine can be supplied with full variable speed.
Variable speed must be specified at the time of order. Variable speed machines are not supplied as calibrated machines.
S2T Group Ltd
125 High Road
North Weald
Essex
CM16 6EA
UK
Tel +44 1992 878 152
