Paint film flexibility test

Paint film is a solid continuous film formed by one or more coatings of paint applied to the substrate. Paint films usually consist of multiple coats, and the number of coats is determined based on the requirements of the object being coated. Generally includes primer layer, intermediate coating and topcoat layer. The coating film reflects the effect of the matching paint.
Flexibility refers to the ability of a paint or putty film to deform with its substrate without breaking. In the paint film flexibility test, a flexibility tester can be used to measure the flexibility of the paint film and putty film. The flexibility of the paint film and putty film is expressed by the minimum shaft rod diameter that does not cause damage to the paint film and putty film.
Zhongke Testing Reliability Experiment Center has the capability of reliability testing of various paint films and provides professional flexibility testing services for paint films.

1) According to use: there are wood paint, iron paint, glass paint, aluminum paint;
2) Divided by state: water-based paint and oil-based paint. Water-based paint is mainly latex paint, while lacquer paint, polyurethane paint, etc.;
3) According to the form of action: volatile paint and non-volatile paint;
4) According to the surface effect: transparent paint, translucent paint and opaque paint.

1. With the paint film of the test panel facing upward, use both hands to press the test panel tightly on the shaft rod with the specified diameter of the paint film flexibility tester. Use two thumbs to bend the test panel around the shaft rod at a steady speed within 25~3 seconds. After bending, the two thumbs should be symmetrical to the center line of the shaft rod.
2. Under the specified natural sunlight or artificial sunlight, observe whether the paint film has reticulation, cracks or peeling. If necessary, use a 4x magnifying glass to observe. The occurrence of netting, cracks and peeling within 2mm of the edge of the test plate will not be included in the test results.
3. If no reticulation, cracks and peeling are observed in the paint film, use a shaft rod with a smaller diameter for bending. If reticulation, cracks and peeling are observed on the paint film, use a shaft rod with a larger diameter for bending.

GB/T 1731-2020 Determination of flexibility of paint and putty films
GB/T 3186 Paints, varnishes and raw materials for paints and varnishes Sampling
GB/T 9271 Paints and varnishes Standard test plate
GB/T 9278 Temperature and humidity for condition conditioning and testing of paint samples
GB/T 13452.2 Paints and varnishes - Determination of paint film thickness
GB/T 20777 Paints and varnishes Inspection and preparation of specimens
GB/T 37356 Paints and varnishes - Lighting conditions and methods for visual evaluation of coatings