VINYLESTER RESINS

Vinylester Resin is a hybrid of Epoxy and Polyester Resins. Various grades of Vinylester Resins are available to suit Hand lay-up, Spray-up, Filament Winding, Centrifugal Casting, RTM, Pultrusion, BMC/SMC etc.. Cured Vinylester Resin has the properties similar to that of epoxy resins coupled with the ease of processing of polyester resins. Vinylester Resins are prepared from Proxy Resin and Acrylic/Metacrylic Acid, though the backbone component of Vinylester Resin can be derived from Polyester Resin, Urethane Resin etc.. Epoxy Resins that have been used for producing Vinylester Resins include epichlorohydrin-bisphenol-A types, the phenolic - novolac types and the tetrabromo Bisphenol A types. For Acrylate Vinylester resins, the low molecular weight Bisphenol A epoxies are used as backbone component. This resin is used in radiation cure application.The curing mechanism of Vinylester Resin is similar to unsaturated polyester resins. For ambient temperature cure MEKP(Catalyst)/Cobalt Octoate or Benzoyl Peroxide/ Dimethylaniline system may be used. For elevated temperature cure Benzoyl Peroxide paste or T-butyl peroxy benzoate is used at 120 - 165oC.

Catalyst system should be selected based on the following criteria :

Desired Gel Time
Effect of mould as a hear sink
Working Temperature
Thickness of the laminate
Application of the laminate