Tiếng Việtservice paint voyager service ct thinner
Key Points
Focusing on the chemical bonds and bond energy of paint resins can help predict the performance of the paint film and determine the suitability for priming or topcoating.
1. Characteristics of Paint Resins
The chemical bonds in resins affect the properties of the paint film. For instance, oil-modified alkyd resin coatings, composed of ester bonds, are weak against alkaline aqueous solutions. On the other hand, epoxy resin coatings, containing ether bonds and benzene rings, exhibit excellent chemical resistance. Silicone resin paints with siloxane bonds (Si-O) tend to be less resistant to alkali.
Epoxy resin paints are suitable for priming due to their rust-prevention properties, but they degrade under sunlight. When touched, the degraded paint surface becomes powdery, a phenomenon known as ‘chalking’. Thus, they are unsuitable for topcoats. Resins like epoxy with multiple benzene rings have little charge imbalance, ensuring good chemical resistance, but they produce R-O-O radicals under sunlight, leading to decomposition.
2. To Maintain High Gloss
For maintaining high gloss, topcoat paints containing fluororesins or silicone resins are suitable. These resins include C-F and Si-O bonds, which show less degradation under UV exposure.
Inorganic polymers with siloxane bonds (Si-O) do not degrade under UV light but are hard and brittle like glass. To compensate for this drawback, paints chemically bonded with flexible acrylic resins have been developed, known as inorganic-organic hybrid resin paints or acrylic-silicone resin paints.