4 factors that affect paint viscosity

There are many factors affecting the viscosity of coatings. In summary, there are mainly the following points:

(1) The composition of the coating and the type of additives The greater the resin content, the higher the viscosity.

(2) The higher the relative molecular mass and distribution of the polymer chain of the film-forming material, the greater the viscosity; the better the flexibility of the molecular chain, the greater the non-Newtonian property of the coating, that is, the dependence of viscosity on shear force bigger.

(3) Fineness of fillers The higher the fineness of pigments and fillers, the better the dispersion and the higher the viscosity.

(4) Solubility of the solvent The better the solubility, the greater the viscosity, the higher the density of the formed film, and the more uniform the structure. During construction, attention must be paid to the choice of diluent.

The viscosity of the paint is also called the consistency of the paint, which refers to a characteristic that the fluid itself has an adhesive force that hinders its relative flow inside the fluid. For any fluid, the viscosity of the system is the basic property of the fluid.

This index directly affects the construction performance, the leveling and sag properties of the membrane. By measuring the viscosity, the degree of polymerization of the paint after storage . According to different construction requirements, the viscosity can be adjusted with a suitable diluent to achieve different viscosity indexes required for brushing and airless spraying.

Paint viscosity can be divided into original viscosity and construction viscosity in the coating process. The original viscosity is the viscosity of the original paint when it enters the factory, and the construction viscosity is also called the working viscosity, that is, the viscosity suitable for a certain coating method.

The viscosity of coatings can be measured by methods such as capillary rheometer and Rotational Viscometer. The national standard CB/T 1723- -93 stipulates 3 methods of measuring viscosity, including the method of measuring the viscosity of paint by Tu-I.Xu-4 Viscosity Cup and falling ball viscometer. Among them in the coating process is Using Tu-4 Viscosity Cup measurement method. This method is simple and easy, that is, the time for 100mL paint liquid to flow out from the aperture with a diameter of φ4mm at a specified temperature is recorded, expressed . This method is suitable for all kinds of low viscosity coatings.