maandag 26 juli 2010

Pigment Volume Concentration - Calculation

The Pigment Volume Concentration (PVC) of a paint is the balance between the volume of pigment and filler mix and the total volume solid content of a paint.
The calculation is:

PVC = (Volume pigment/filler mix / total solid volume paint)x 100%

Critical Pigment Volume Concentration (CPVC)
Besides the PVC of a paint there is also the Critical Pigment Volume Concentration and this is the situation were the pigment/filler mix is just covered with the resin of the paint. Above the CPVC the properties of a paint will change dramatically.
The CPVC can be calculated as follows:

CPVC = (VPF x 100%)/VPF + ((WPF x OA/100)/density solid resin)

were is:
VPF = Volume pigment/filler mix
WPF = Weight pigment/filler mix
OA = Oil Absorption of pigment/filler mix

Pigment Volume Balance (PVB)
The Pigment Volume Balance is the balance between the PVC and the CPVC according the following formula:


Because there is a correlation between the balance of these three parameters and the properties of a paint, the paint formulator has with these calculations an important tool to formulate/calculate his best starting point paint formulations.

For different paints, depending on the application the PVC and PVB can vary between the following values:

Topcoats the PVC can vary from 5 - 20 and the PVB 0,10 - 0,40
Primers,the PVC can vary from 30 - 40 and the PVB 0,50 - 0,75
Anti Corrosive Primers, PVC 35 - 40 and the PVB 0,60 - 0,80
Wall Paints, the PVC can vary 35 - 80 and the PVB 0,60 - 1,70