Shock (paint)
A specific defect in paint production is called shock . Symptoms of shock usually occur when completing . Depending on the previous history, a distinction is made between binder shock , solvent shock and pigment shock .
Basics
In the dispersion of pigments and fillers in a paint often have different requirements for ground material and finished paint are provided. The regrind must therefore be adjusted to the finished lacquer ( let down ). If the two components differ too much or if you work carelessly, strong concentration gradients occur which can lead to flocculation , i.e. the agglomeration of already dispersed pigment particles.
Shock phenomena are problematic because they lead to the appearance of specks in the paint film and because the approach usually has to be discarded after the processing error has occurred.
Types of shock
Solvent shock
With the addition of solvents or high solvent mixtures to the grind it comes to the diffusion of the binder into the solvent. As a result, the grist is depleted of binding agent at certain points, so that the pigment particles contained can no longer be kept stable and clump together again ( flocculate ). A pigment shock can also occur if the added solvent is not compatible with the rest of the paint system.
Pigment shock
A pigment shock can occur if a binder solution with a higher binder content than the millbase is added to it. Since there is less solvent in the added solution than in the ground material, it diffuses out of the ground material. This triggers destabilization and thus flocculation of the pigments and fillers in the areas that are now less solvent-free.
Binder shock
Binder shocks can only occur if the constituents of the paint used are not completely miscible with one another or if, during the completion of the process, there are concentration ranges in which the binder is no longer completely soluble. If there is such an incompatibility, it can lead to the precipitation of binder components. In the paint film produced specks . If the resulting coagulate contains pigment particles, the specks also contain pigment particles.
Individual evidence
- ↑ a b c G. Meichsner, T. Mezger, J. Schröder; Measure and control paint properties; Page 197f Vincentz Network; Hanover; 2003; ISBN 3878707398
- ↑ a b A. Goldschmidt, H. Streitberger; BASF Painting Technology Handbook; Page 221; Vincentz Network; Hanover; 2002; ISBN 3878703244
- ↑ H. Römpp; Römpp Lexicon Lacquers and Printing Inks; Page 360f; 1998; Thieme; Stuttgart; ISBN 9783137760016
- ↑ H. Römpp; Römpp Lexicon Lacquers and Printing Inks; Page 453; 1998; Thieme; Stuttgart; ISBN 9783137760016
- ↑ H. Römpp; Römpp Lexicon Lacquers and Printing Inks; Page 75; 1998; Thieme; Stuttgart; ISBN 9783137760016