PLYMOUTH, IN—A new "ULTRA TIECOAT" formulation introduced by the Liquid Coatings & Dispersions Division of Ferro Corporation allows the adhesion of unsaturated polyester gelcoats to epoxy laminating resins, reports Thomas Loschiavo, marketing manager.

The coating, catalyzed with 1.5 to 2.5 percent MEKP, is applied at 15 to 20 mils and allowed to cure for two to three hours at a minimum temperature of 70ºF (21ºC) prior to laminating with epoxy resin.

In addition to meeting the ASTM D-790 standard for bond strength, the tie-coat is said to increase film toughness and water osmosis resistance while decreasing fiber pattern and print-through.

At 77ºF (25ºC) the uncured coating has a viscosity of 2000-9000 cps and gel time of 8 to 12 minutes (1.5 percent MEKP). Peak exotherm is 300 to 366ºF (149 to 186ºC). The cured coating exhibits 3.5 percent flexural elongation and 300ºF (149ºC) heat distortion temperature.

Other gelcoat products manufactured by the division include SuperShield® low-VOC Super Performance gelcoat, ULTRA™ 1-NPG and ULTRA Plus NPG/ISO gelcoats, ULTRA low-VOC gelcoat, ULTRA clear gelcoat, and ULTRA K-Anticandela fire retardant coating.

Gelcoats products are used in the molding of boats, recreational vehicles, truck bodies, sanitaryware, swimming pools, and other polyester and epoxy composite parts and castings, to produce colorful, durable finishes that resist moisture, chemicals, impact and UV light.