Page 96 - Chemical and process design handbook

Speight_Part II_A 11/7/01 3:16 PM Page 2.37

ALKYD RESINS 2.37
tages include good gloss retention and fast drying characteristics.
However, most unmodified alkyds have low chemical and alkali resistance.
Modification with esterified rosin and phenolic resins improves hardness
and chemical resistance. Styrene and vinyl toluene improve hardness and
toughness. For high-temperature coatings (up to about 230°C), copoly-
mers of silicones and alkyds are used. Such coatings include stove and
heating equipment finishes. To obtain a good initial gloss, improved adhe-
sion, and exterior durability, acrylic monomers can be copolymerized with
oils to modify alkyd resins.