Viscosity of paint film and its determination

Paint film is a common way to protect, beautify and improve the surface of objects and is widely used in various fields such as construction, automobiles, furniture, etc. However, in addition to the appearance and abrasion resistance of the paint film, stickiness is an important indicator that is often overlooked, and it may appear and cause problems after the paint film is dried. Stickiness can cause a range of problems, especially in certain environments, such as hot and humid climates or high temperature seasons. Stickiness can cause adhesions to the surface of the paint film, such as dust, dirt or Miscellaneous impurities, which can affect the appearance of the paint film. If the paint film has obvious stickiness, the coatings may stick together during handling, transportation or installation, causing operational problems and inconveniences. The stickiness of the paint film may reduce its abrasion resistance and chemical resistance performance, thereby reducing the service life of the coating. Paint films with stickiness may be more difficult to clean and maintain, which may increase maintenance costs and workload.

What is stickiness?

Reshesion refers to the phenomenon that the paint film may re-adhere after drying under certain temperature and Humidity conditions. This phenomenon can cause the paint film to re-block in certain environments, causing unnecessary trouble and damage to the surface. Reshesion usually occurs more easily in high temperature and high humidity environments, so it can become a serious problem in some specific applications, such as tropical regions or high temperature seasons.

Viscosity of paint film and its determination Figure 1

Test method for viscosity:

To determine the viscosity of the paint film, the specified method of GB/T 1762-80 "Determination of the viscosity of the paint film" can be used. The test steps include:

  1. Place the filter paper glossy side down on the paint film.

  2. The preheated viscosity Tester is placed in the middle of the filter paper and placed in a Temperature-Specific Humidity Circulating Oven.

  3. Within 5 minutes, the temperature was raised to 40 ℃ ± 1 ℃ and the relative humidity was raised to 80% ± 2%.

  4. Hold for 10 minutes under this condition.

  5. Quickly remove the measuring device vertically upward, take out the sample and observe the condition of the paint film. The results are expressed in grades.

This test method can help determine whether and to what extent the paint film will stick back under high temperature and humidity conditions.

Adhesion is an important factor that can cause surface problems of paint films, especially in high temperature and humidity environments. By understanding, testing and managing adhesion, manufacturers and engineers can ensure that coatings maintain their performance and Appearance under different conditions. During the design, application and maintenance of paint films, adhesion issues should receive sufficient attention to ensure the mass and durability of coatings.


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