Overview
ISO 2006-2:2009 - Rubber latex, synthetic - Determination of mechanical stability - Part 2: Moderate-speed method under load specifies a laboratory test method (Maron method) for measuring the mechanical stability of synthetic rubber latex. The standard determines mechanical stability by stirring a measured latex portion at a moderate speed under load and quantifying the mass of coagulum formed. The result is reported as the percentage of coagulum relative to the latex total solids content.
Key topics and technical requirements
- Test principle: Stir a defined test portion under shear (patterned rotating disc pressing on a polyethylene liner) for a set time; separate, dry and weigh coagulum.
- Typical test conditions:
- Stirring speed: 1 000 min⁻¹ ± 20 min⁻¹
- Loads commonly used: 49 N, 98 N or 147 N (± 2 N) - chosen in preliminary trials for the specific latex
- Test durations: 300 s or 600 s, selected based on expected stability
- Test portion: 50 g ± 0.5 g
- Apparatus: mechanical stability tester able to maintain load up to 500 N; rotating disc and grooved flat-bottom latex container; preliminary and test filters of ~180 µm mesh (ISO 3310-1 compliant).
- Reagents and sample handling: carbonate-free distilled water; 5% potassium oleate surfactant (or alternative if incompatible); sampling per ISO 123; total solids content measured per ISO 124.
- Result expression: coagulum mass expressed as a percentage of the latex total solids content (mass of dried coagulum relative to test portion and TSC).
- Quality and reporting: tests performed in duplicate; report must include test conditions (load, time, temperature), TSC, coagulum percentage (to two decimals), and any deviations.
Practical applications and users
- Who uses it: latex manufacturers, QC laboratories, R&D teams, rubber product formulators, and test-equipment suppliers.
- Why it matters:
- Predicts latex behaviour during mechanical processing (mixing, pumping, creaming) by simulating shear under load.
- Supports product acceptance, process troubleshooting and formulation optimization by quantifying tendency to coagulate under realistic stress.
- Useful for comparing batches, qualifying stabilizers/surfactants and verifying equipment impacts on latex stability.
Related standards
- ISO 2006-1: High-speed method (Klaxon method) - complementary mechanical stability test.
- ISO 123: Rubber latex - Sampling.
- ISO 124: Latex, rubber - Determination of total solids content.
- ISO 3310-1: Test sieves - Technical requirements (filter mesh specification).
Note: ISO 2006-2:2009 includes an informative precision annex from an interlaboratory study and warns users to follow normal laboratory safety and reporting practices.
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