Rubber toughened epoxy resins ALBIPOX®
Epoxy resins have a substantial disadvantage: Their brittleness.
This disadvantage can be more than compensated by an elastomer modification (so-called "toughening" or impact resistance modification). In contrast to an elastification, the elongation at break of the cured modified resin normally remains under 10 percent.
The toughening of epoxy resins proves to be difficult, however. Thus, for example, the use of flexible hardeners or the addition of non-reactive flexibilizers significantly impairs a number of important properties such as tensile strength and modulus, thermal and chemical resistance as well as thermodimensional stability.
These negative effects can be avoided by toughening with copolymers based on reactive elastomers. However, the pure liquid elastomers are only slightly miscible with epoxy resins, if at all.
The different ALBIPOX® grades are reaction products between epoxy resins and an elastomeric copolymer. Hereby, an excess of epoxy resin is reacted with the reactive liquid elastomer. After the reaction, the elastomer molecules are epoxy functional and will be chemically bonded to the resin matrix during curing.
ALBIPOX® products can be used by epoxy resin formulators like a modular system. There are no limitations in respect to the resins and hardeners that can be used. Typical addition levels are 25 - 40 percent.