Epoxy Esters Coatings
Epoxy ester resin is a product obtained through the esterification process of vegetable oil and epoxy resin. This resin imparts good flexibility and color to coatings.
Epoxy ester coatings are primarily used for post-printing varnishing. They are suitable for a wide range of products, including tinplate cans, deep-drawn tins, twist-off caps, crown caps, and various other cans.
Most epoxy ester coatings are colorless, but by adding dyes, golden epoxy ester coatings can be obtained for decorative applications on the external surfaces of twist-off caps and crown caps. The main properties and advantages of these coatings are as follows:
- Excellent gloss
- Good color fastness, which is crucial for external designs
- Combination of flexibility and good hardness
- Excellent ink compatibility, especially applicable in the “wet-on-wet” production process
Compared to other synthetic coatings, epoxy ester coatings are one of the most versatile varieties. They can achieve the same level of gloss as oil-based varnishes while overcoming the drawbacks of poor color fastness and susceptibility to yellowing.
Curing of epoxy ester coatings is achieved through oxidation and thermal polymerization. For can production, when high color fastness of the ink is required, a peak temperature of 160-180°C is generally used, with a heating time of up to 10 minutes. Within this temperature range, the color difference in the dry film is minimal. When used for products resistant to boiling, a peak temperature of 190°C and a heating time of up to 10 minutes are required to maximize water and steam resistance.