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Stereolithography is a new technology which allows the rapid building of plastic models directly from CAD data. The photopolymers needed for this process are developed at Ciba's research center in Marly by a project team from the Polymers Division and the corporate Materials Research. The stereolithography process is described as well as the requirements for the photosensitive monomer formulations. Two types of stereolithography resins have been developed so far: acrylate mixtures which polymerize by a radical mechanism and epoxy-based formulations which are cured cationically. The acrylate resins polymerize very rapidly and several formulations with different mechanical properties are available. Cationic resins are a development of the past two years. They are less photosensitive than the acrylates, but have other advantages, such as low viscosity, high green strength and very high dimensional accuracy. With these resins, parts can be built which can be used directly as patterns for the investment casting process.

Successful adhesive technology relies on the diligent engineering of adhesive and cohesive forces. Polymers thereby play the dominant role as they largely determine the chemical and physical properties of the adhesive joint. A wide range of polymer systems is available, each having special properties in its own right. The art of adhesive formulation lies in the right choice of the appropriate polymer and its modification to suit the purpose. This article provides several examples of adhesive applications in demanding industry segments.

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