Paint System



A BC_CC paint system comprises; a clear coat, which has no pigmentation (colour) that provides both protection and depth of gloss for the base coat. A base coat or colour coat has a pigmentation added to provide the vehicle colour.



Polymer degradation [: a change in the properties; tensile strength, colour, shape, etc f a polymer or polymer-based product under the influence of one or more environmental factors such as heat, light or chemicals such as acids, alkalis and some salts]



The clear coat is the final original equipment manufacturers coating applied to a vehicle to protect the (base) colour coat while providing both depth and a durable, glossy appearance, originally designed to protect metallic paints, but is now applied to all colours. Any product applied on top of the clear coat needs to be transparent otherwise both the paint colour and its depth of shine will be muted.



Many natural and synthetic materials are attacked by ultra-violet radiation and products made using these materials may crack or disintegrate. This problem is known as ultra violet photo degradation, and is a common problem in products exposed to sunlight.



Ultra violet (UV) radiation is known to contribute to the chemical modification (drying out the polymers and its resin binder system) of exposed paint surfaces resulting in loss of gloss, color change, chalking, flaking and eventually destruction of the paint film










Photo-oxidation of polymers



Photo-oxidation (sometimes incorrectly described as oxidation) [: the degradation of a polymer surface in the presence of oxygen or ozone]



Photo-oxidation (sometimes incorrectly described as oxidation) is a consequence of ultra violet (UV) radiation, which instigates a chemical change that reduces the polymer`s molecular weight. As a consequence of this change the material becomes more brittle, with a reduction in its tensile, impact and elongation strength. Discoloration and loss of surface smoothness accompany photo-oxidation. Infra red (heat) radiation or high surface temperature significantly increases the effect of photo-oxidation.






Clear coat failure- is the result of ultra violet radiation drying out both the polymer paint and its resin binder system, causing structural failure; the paint take on a dull grey cloudy appearance, then as time progresses this is accompanied by paint delamination (flaking) Once a paint surface structural integrity is compromised like this it usually means the paint requires replacement (re-painting)



It’s also worth noting that the UV absorbents migrate to the top of the clear coat, so one you remove too much clear 0.5 mil (12µ) you`ll have no paint ultra violet protection other than what you apply with a LSP



Relevant Articles



1. http://www.autopia.org/forum/car-det...-removal.html#