Feasibility study on the overcoatability of UV coatings

In a current paper, approaches are being sought to improve the recoatability of UV coatings. Different approaches are chosen to change the surface properties.

A paint spray gun as a symbolic image.
By modifying the drying and cross-linking processes of the paint Image source: Ralfador Ralfadinski - Pixabay (symbol image).

The pre-treatment methods of the first layer ensure better wetting, adhesion and bond strength between the UV coating substrate and the repair coating. On the one hand, the surface is pre-treated physically or wet-chemically. On the other, primer is used, which is applied as an adhesion-promoting layer. As part of a further investigation, the UV coating is modified in its formulation to bring about better adhesion for the subsequent layer. Another experiment is to adjust the drying sequences to allow overcoating. For this purpose, the coating is merely gelled under certain drying conditions.

Changing the drying and curing processes

The limits of overpaintability are determined by means of double bond conversion and polyaddition conversion. The surface energies are related to the wettability and the adhesion. Conditions of bond strength are established and discussed. Grinding with P3000 abrasive paper and wet chemical treatments result in good adhesion. It is also shown that silicone additives can cause wetting problems. By modifying the drying and cross-linking processes of the paint, overpaintability is ensured.

The study was conducted by Dennis Neuerer as a bachelor thesis at the Esslingen University. It is subject to an blocking period until 28 February 2027.

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