Behavior in Paint Systems

The time that is required to produce a homogeneous suspension of particles in the dispersion medium using an oscillatory shaking machine equipped with several containers is measured. Not only can small quantities of the millbase with the same composition be tested (as with other types of apparatus), but various millbases can also be tested under the same conditions. A low-viscosity alkyd resin system of the stoving or oxidatively drying type can be used as a test medium. For standards, see Table 1.1 ( Ease of dispersion Oscillatory shaking machine ). 

The dispersion properties are determined with an automatic muller. The advantage is that small amounts of material can be simply tested under reproducible conditions. For standards, see Table 1.1 ( Ease of dispersion Automatic muller ). 

Change in Tinting Strength, Half-Life Times, and Increase in Strength 

Making use of equations used in the description of the kinetics of chemical reactions a quantitative description of the dispersion process can even be achieved [1.22] by defining three types of size reduction of large particles  

Pigment Volume Concentration (PVC) and Critical Pigment Volume Concentration (CPVC) 

Low-Viscosity Media. The time is measured that is required to produce a homogeneous suspension of particles in the dispersion medium using an oscillatory shaking 

Pigment Volume Concentration (PVC) and Critical Pigment Volume Concentration (CP VC). The pigment volume concentration ( r) is the fractional volume of pigment in the total solids volume of the dry paint film  

Under CP VC conditions, the pigment particles are at a maximum packing density, and the interstices are completely filled with binder. With smaller amounts of binder, the interstices are incompletely filled. The CPVC thus represents a pigment concentration boundary at which abrupt changes in the properties of the film occur. 

The methods of determining the CPVC [1.82] are divided into two groups  

---