Polyesteriresiinit

Polyesteriresiinit, or polyester resins, are a family of thermosetting polymers produced by condensation reactions between diols (glycols) and dicarboxylic acids, often with an unsaturated component that enables crosslinking. They are widely used as binders in fiberglass-reinforced composites, coatings, adhesives, and casting resins. The most common form is unsaturated polyester resin (UPR), formed from diols such as ethylene glycol and dicarboxylic acids like phthalic and maleic anhydride, with styrene or vinyl esters added as reactive diluents and crosslinking partners. On curing, free-radical polymerization links the double bonds to form a rigid, heat- and chemical-resistant network.

Vinyl ester resins are related systems made by reacting epoxy resins with unsaturated acids or anhydrides to introduce vinyl groups; they typically offer higher chemical resistance and better adhesion to metals and glass fibers than standard UPRs. Saturated polyester resins, which contain little or no carbon–carbon double bonds, cure via different mechanisms and are used in specialized coatings and composites where particular mechanical or thermal properties are desired.

Applications for polyester resins include boat hulls and other marine composites, automotive parts, wind turbine components, corrosion-resistant linings, and topcoats for reinforced laminates. They are valued for relatively low cost, good mechanical strength, and versatility in formulations. Processing involves combining the resin with a initiator such as a peroxide and a reactive diluent (often styrene) to achieve workable viscosity, followed by cure to a infusible, crosslinked network.

Safety and environmental aspects center on styrene emissions during processing, skin and inhalation hazards, and the challenges of recycling crosslinked thermosets. Proper ventilation and handling procedures are recommended.