Overview
ISO 1147:1995 specifies a standardized freeze-thaw cycle stability test for polymer dispersions and synthetic rubber latices (not applicable to natural rubber latex). The standard defines a repeatable procedure to evaluate whether aqueous dispersions withstand defined low-temperature storage and recovery cycles without irreversible coagulation or unacceptable changes in viscosity. It replaces the earlier (1988) edition and is intended for use in quality control, formulation development and material specification.
Key topics and requirements
- Scope: Applies to polymer dispersions and synthetic rubber latices; excludes natural rubber latex.
- Test sample: 100 g ± 1 g placed in a cylindrical container (height 100 mm; inside diameter 40 mm; wall thickness 2 mm). Container material: polyethylene for freeze temperatures of −5 °C or −10 °C, stainless steel for lower temperatures.
- Freeze-thaw cycle: Typical cycle is 16 h at a selected freeze temperature (−5 °C, −10 °C or −20 °C with stated tolerances), then 8 h thaw at 23 °C. The chamber temperature must be controlled to ±0.5 °C.
- Measurements and checks:
- Initial viscosity measured at 23 °C using a rotational viscometer / Brookfield method in accordance with ISO 3219 or ISO 2555.
- After thaw, inspect by stirring (glass rod) for visible, indispersable coagulum; if inconclusive, remeasure viscosity.
- If viscosity change exceeds the manufacturer’s specification limit or irreversible coagulation occurs, the test is completed. Otherwise, repeat up to a maximum of three cycles.
- Result expression: Report the number of cycles endured without visible coagulum or a viscosity change exceeding the manufacturer’s limit.
- Reporting: Test report must include reference to ISO 1147, product identification, freeze temperature used, method of viscosity measurement, initial and final viscosities, number of cycles, any modifications, and test date.
Practical applications and users
ISO 1147 is valuable for:
- Manufacturers of polymer dispersions, synthetic rubber latices, adhesives, paints and coatings who need to demonstrate storage and transport stability.
- Quality control and R&D laboratories performing acceptance testing or formulation optimization.
- Procurement and specification engineers requiring objective criteria for freeze-thaw resistance.
- Regulatory or certification bodies assessing product fitness for cold-climate distribution.
Using ISO 1147 helps reduce batch failures, optimize stabilizer systems, and ensure reliable performance after cold storage or shipment.
Related standards
- ISO 3219 - viscosity determination of polymers using rotational viscometers.
- ISO 2555 - Brookfield test method for apparent viscosity.
- ISO 12000 - definitions and review of test methods for polymer dispersions and latices (referenced).
Keywords: ISO 1147, freeze-thaw cycle stability test, polymer dispersions, synthetic rubber latices, latex stability, viscosity measurement, Brookfield, freeze-thaw resistance.
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