Лако-красочные материалы — производство

(i) Acrylic Resins The formulation of acrylic resins for electrodeposition is not very different from formulating them for any other use. There are so many acrylic monomers available that almost any property desired can be incorporated, so it is just a matter of selecting the right monomers, initiators and solvent. Solvents should preferably be water […]

As with any other surface coating, it is the final application which governs the choice of the chemical structure of the polymer, because the performance of the film depends more on its chemical structure than on the particular method of applying the film. However, it is worth going through the major requirements of the most […]

This is governed largely by the ultimate application of the paint and so is more under the control of the paint formulator than the resin formulator. Single coat whites are, for example, usually cured with a melamine or other amino resin. The melamine resin has to be suitable for this particular use, and a number […]

These need to be between about 50 and 100 mg KOH/g, to give adequate bath stability after neutralisation. The actual value depends on the chemistry of the system, and on the crosslinking mechanism envisaged. It is probably best to keep it to the lower end of this range as far as possible, provided the final […]

This cannot always be determined, but for acrylic resins, for example, it can be calculated approximately. The actual glass-rubber transition is of only minor interest either for deposition, or for use, but its value is related both to properties such as the brittleness and flexibility of the final film, and also to the melting point […]

(i) Molecular Weight This should not be too high, otherwise the flow of the film during deposition will be adversely affected. The film needs to be liquid when it contains pigment and crosslinking agent, and so the resin system needs, in fact, to be quite low molecular weight to bring this about. It needs to […]

Polymers for electrodeposition are formulated as polyelectrolytes. That is to say that they are made containing a proportion of functional groups which, when reacted with an acid or a base, as appropriate, will have a multiplicity of ionic groups along the chain. These ionic groups make the polymer compatible with water. In some cases the […]

Acrylic resins are used for both anodic and cathodic electrodeposition. A detailed discussion of electrodeposition will not be given here. Consult Oldring et al (Vol. Ill Resins for Surface Coatings published by SITA Technology) for further details. Acid functional acrylics neutralised with tertiary amines are used for anodic systems, whilst amine functional acrylics neutralised with […]

(Courtesy of Shell Chemicals) In this example, butyl glycol is the solvent. Hydroxyl functionality comes from hydroxy ethyl methacrylate. If required, the resin can be neutralised and dispersed or supplied as is for the coating formulators to add the amines of their choice. FORMULATION 2-14 VeoVa 10* 34.60 Acrylic acid 8.09 Hydroxy ethyl methacrylate 12.17 […]

Waterborne resins for surface coatings are not only prepared by an emulsion copolymerisation technique. They can be prepared using a solution technique with a water soluble organic solvent, or in water. This is the least common. The solution technique uses water soluble solvents, such as alcohols, (e. g. butanol, propanol) glycol ethers (e. g. butyl […]