What is Minimum Film Forming Temperature (MFFT)?

It is the lowest temperature at which the polymer particles in an acrylic emulsion will fuse together to form a continuous, crack-free film (Clause 4).

Why is MFFT important for a waterproofing coating?

If a coating is applied below its MFFT, it will dry into a powdery or cracked layer that offers no waterproofing protection. The film fails to form correctly.

What is the 'White Point' temperature?

It is the temperature at which a clear, dried film of the polymer turns opaque upon cooling, which can be relevant to its performance and appearance in cold service conditions (Clause 5).

What is the main equipment used for this test?

The primary apparatus is an MFFT Bar, a metal plate with a precisely controlled temperature gradient, along with a film applicator to create a uniform film (Clause 3).

IS 13435

: 2000

Acrylic-based polymer waterproofing material - Methods of the test, Part 4: Determination of Minimum Film Forming Temperature and White Point

CurrentSpecializedTesting MethodMaterials Science · Waterproofing and Damp-Proofing

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This standard specifies the test method for determining two critical thermal properties of acrylic-based polymer dispersions used for waterproofing: Minimum Film Forming Temperature (MFFT) and White Point. MFFT is the lowest temperature at which the liquid material can properly cure into a continuous, effective waterproofing film.

Acrylic-based polymer waterproofing material - Methods of the test, Part 4: Determination of Minimum Film Forming Temperature and White Point

Quick Reference Values

Typical MFFT Apparatus Temperature Range-5°C to +75°C

Specified Wet Film Thickness for Test75 ± 5 microns

Definition of MFFTThe lowest temperature at which a latex will uniformly coalesce when laid on a substrate as a thin film.

Definition of White PointThe temperature at which a dried film of the polymer dispersion turns white or opaque upon cooling.

Dry Air Flow Rate over Film2-4 litres/minute

Practical Notes

The MFFT value is crucial for determining the safe application temperature range for a waterproofing product; applying it below the MFFT will lead to film defects and failure.

This test is primarily used by manufacturers for quality control and by testing laboratories for product certification, not typically performed on-site.

Results from this test directly inform the Technical Data Sheet (TDS) and application guidelines for waterproofing materials, especially regarding use in different climates.