5.7. Renewable Unsaturated Polyesters
Renewable or fossil UPs are thermosetting resins.
5.7.1. Renewable Grades
Partially renewable UPs are slowly developing but renewable content, sometimes including recycled materials, can be as low as 8% up to 55%. Biopolyols, originated, for example, in soy or glycerol released in the production of biodiesel, partly replace petroleum-based components.
Please note that green or bio- or eco-UP resins may be:
• derived from biologically renewable materials
• derived from recycled materials, and/or
• free of styrene.
Among others, let us quote some materials formulated for casting, cured-in-place pipe (CIPP), closed molding, and open mold laminating: EcoTek line by AOC, Envirez line by Ashland, Envirolite by Reichhold, ...