Resin

Polyester Resin is the most widely used resins in the composites industry. Polyester Resins are typically less expensive and much easier to apply than Epoxy resins. There are several versions in the class of Polyester Resin; Orthophthalic, Isophthalic, DCPD, and then blends of all of these. The purpose of these versions of Polyester Resins is due to the specific cured characteristics. The Orthophthalic version is considered the economic leader. The Isophthalic is corrosion resistant and widely used in the marine industry, pipe and tank containment repair, as well as tooling / molds. DCPD is a great product for a “low profile” surface of the fiberglass parts for automotive finishes. The majority of all fiberglass parts are constructed using Polyester Resins because they are easy to use, fast curing, and tolerant of temperature and catalyst extremes. When used in hybrid form, you are able to blend and obtain the preferred characteristics.

Vinyl Ester Resin is considered to be a hybrid of polyester and epoxy resins—meaning it has the easy and fast handling characteristics of a polyester, yet it has the cured properties of an epoxy (tough, corrosion resistant, high elongation. Some of the characteristics of a vinyl ester resin are perfect for high heat distortion, durability, and impact strength.

Epoxy Resins are considered to be the most advanced on the market. There are many versions that cover the gamut of structural properties required. Generally, epoxy systems need to be elevated temperature post cured to acquire the mechanical properties they are known for. They often require more accuracy in measurement and handling and are more expensive. However, the increase in mechanical properties is worth the investment for any application where strength-to-weight is critical. Epoxy components are also more sensitive to UV degradation and will yellow when left unprotected.