Лако-красочные материалы — производство

To gain insight into the adhesive-surface interaction on a molecular level, and thus compare the effectiveness ofdifferent surface preparation procedures, contact angle measurements have frequently been discussed. Prediction of the adhesive properties of a surface based on its interfacial tension can be possible because adhesion will only take place if the adhesive wets the adherent […]

In corona treatment, a high-frequency voltage is applied between two electrodes or between an electrode and the substrate material. This causes the atmosphere between the electrodes to become ionized, and a corona discharge is ignited. When introducing an insulator between the electrodes, its surface is targeted with ions and radicals, causing a modification of the […]

In low-pressure plasma treatment the adherents are placed in a process chamber that is then evacuated. After introducing a process gas, the plasma is ignited by means of a high-frequency voltage or microwave excitation. The color, lightness and distribution of the plasma arc depend on the pressure in the chamber and the type of process […]

The plasma generator consists of a ceramic tube surrounded by an electric conductor made from sealed metal powder. In the center, an electrically conductive rod with good thermal conductivity (inner electrode) acts as a counter-electrode. An ionizable gas (e. g. air, oxygen) is introduced into the ionization gap between the inner wall of the ceramic […]

In a microplasma burner, the plasma arc between the tungsten electrode and the workpiece is initiated by means of a pilot arc. The process gas between the electrode and the workpiece becomes ionized and the flow of gas directs the plasma to the surface to be treated. Microplasma pretreatment is easy to handle, but the […]

Physical surface pretreatment methods are mainly used for polymer surfaces to increase their polar free surface energy. 6.2.3.1 Flame Treatment During flame treatment, the polymer materials are gently touched by an open flame with a surplus of oxygen. This induces an oxidative effect that improves the adhesion properties, especially in the case of nonpolar plastics, […]

Chemical surface preparation can have two different effects on the surface of the adherent: • Non-oxidizing acids (e. g. hydrochloric acid, dilute sulfuric acid) cause an electro­chemical oxide/acid or metal/acid reaction which results in removal of the oxide layer or, if etching times are long, of the deeper metallic interfaces. In this method — called […]

Brushing also acts as a special type of abrasive surface preparation. For a given size of grit, the surface roughness obtained by brushing is less than that achieved with grinding, due mainly to the fact that, compared to the grinding wheel, the brushes are relatively elastic. It is again essential that the surfaces are degreased […]

As the adhesion properties of surfaces after grinding with abrasives are poorer than those of blasted surfaces, it is recommended that the adherents should be ground at right-angles to the loading direction, or crosswise. Before grinding, the surfaces must be carefully degreased since, if the contaminations are not removed they will be distributed uniformly over […]

6.2.1.1 Grit Blasting Grit blasting is carried out by aiming abrasive materials (e. g. corundum) by means of a jet of air onto the surface to be treated. The degree of abrasive surface removal and deformation caused by the particle impact is determined by the form and hardness of the blast medium, the applied pressure, […]