Organic coatings components

All organic coatings show varying degrees of solubility and permeability for components of the corrosive medium, which can be described as permeation and ionic conductivity (see Sections 5.2.1 and 5.2.2). An absolute separation of protected object and medium is not possible because of these properties. Certain requirements have to be met for corrosion protection, which must also take account of electrochemical factors [1] (see Section 5.2). 

Microgels have also been detected as a component of alkyd resins, an early but still important binder of organic coatings [316-321] and are accountable for their ability to fill pores, fissures and other irregularities of the substrate such as wood. This property may be explained by the size of the microgels which prevents the paint becoming soaked up by the substrate. 

The industrial production and application of reactive and non-reactive microgels in organic coatings such as binders or components of binders, e.g. together with, e.g. acrylic and/or melamine/formaldehyde resins, especially for automotive coatings, was reported in a number of publications between 1980 and... 

A typical example of semi-quantitative analysis of an organic coating on a metal surface is shown in Fig. 7.6. A matted metal sheet is industrially spray-coated with a colourless two-component coating. The task was to determine not only the coverage, something that could also be achieved by using reflectance sensors, but also whether the mixing ratio is within the specification. 

Figure 7.6 Semi-quantitative analysis of an organic two-component coating on a metal surface. The classifier grades the results into within specification (light grey), warning (white), mixing ratio/coverage outside specification (dark grey) and surface defects on the metal carrier (black). A significant isolated problem, B localised constant problem, C acceptable localised random flaws, E start of massive failure, F localised application of primarily one component only due to spray nozzle obstruction.

Tamarind has tartaric acid as its major organic acid component. Many polyphenols are found in the coat of the tamarind fruit. Tamarind kernel powder (TKP) has a xyloglucan, which has a variety of uses. TKP, a crude extract of tamarind seeds, has been used as a replacement for... 

DIN EN 14879-4, Organic Coating Systems and Linings for Protection of Industrial Apparatus and Plants Against Corrosion Caused by Aggressive Media — Part 4 Linings on Metallic Components, 2008. 

In a further work, Tang and Curtis26 have studied the influence of the tyre components by replacing coal with model compounds 4-(l-naphthylmethyl)-bibenzyl (NMBB), dibenzothiophene and 5-methyl-8-(l-methylethyl)dibenzo-thiophen-4-ol (MMDH). Carbon black was active for the NMBB hydrocracking, whereas little activity was found with SBR, waste tyres and waste tyre liquefaction residues. However, when the latter residues were previously heat treated to remove organic coatings and recover the carbon black component, significant NMBB conversions were observed. Moreover, both carbon black and heat-treated residues were active for the hydrodesulfurization of dibenzothiophene and MMDH, particularly when combined with Mo naphthenate and S. These results confirm the catalytic properties of carbon black in coal-tyre coliquefaction, provided that its surface area is accessible. 

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