Treballs Finals de Grau d'Enginyeria Química, Facultat de Química, Universitat de Barcelona, Curs: 2014-2015, Tutors: Dra. Carme González Azón i Sr. Lluís Martínez Barrio
All the objects are vulnerable in their surface, since this is the one which is in permanent contact with the air and with all the factors that can make them some damage. To prevent or to reduce the lesions that can cause this damage, layers or coatings are applied to protect the paint surfaces. Apart from that, the paint also serve to add colour and lustre, to smooth and make disappear the caused irregularities in the fabrication process.
In this project, a specific type of paint is used, a topcoat or a single layer paint. This paints must comply with a several properties and requirements to ensure a good quality of the coating.
From the components that the paint incorporates, the resins are noted, since they are the component which forms the film that identifies the paint and the pigments, which are the particles that determinates the colour of it. In automotive coatings, the paints are applied to a certain conditions of temperature and viscosity. These are applied on a specific substrate, with automotive coatings, it is usually used a certain plastic named PC-ABS (a mix of polycarbonate and acrylonitrile butadiene styrene) or on PP (polypropylene). In this project, the application is carrying out using the conventional aerographic method, with paint applicators or suction guns. It is important that after applying the paint, the solvents are evaporated and a dry film is formed.
For the acceptance of a paint in the automotive industry, a several exigencies has been to accomplish which are imposed by the OEMs (Original Equipment Manufacturer). These specify a several tests to accomplish the chemical and mechanical resistances that has to present the paint to be accepted by the customer.
In this project, it is wanted to achieve a topcoat that has good adherence, good appearance, a good abrasion scratch resistance and good chemicals resistance. To this end, some different tests are performed that will show if the studied topcoat has the wished mechanicals properties.