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SynopsisSolid ketone-formaldehyde resins are used in certain coating formulations in order to improve hardness, gloss, and light stability. They are soluble, thermoplastic by nature, and contain limited amounts of hydroxyl groups. We found that their primary hydroxyls can be etherified with epichlorohydrin (ECH) either by a two-step ECH-addition/dehy&ohalogenation procedure or by a one-step phase-transfer process. An intermediate of particular usefulness is the crystalline 2,2,6,6-tetramethylol-cyclohexanol (TMCH) made from cyclohexanone and 5 mol formaldehyde, yielding low colored epoxy resins with epoxy values up to 7.5 eq/kg. Depending upon the nature of the curing agent, high Tp solids as well as tough and flexible coatings with good outdoor stability can be made. Upon decreasing the formaldehyde-cyclohexanone ratio, solid condensation polymers melting up to 150°C can be obtained. Phase-transfer glycidylation yielded solid thermoset glycidyl ether resins with a,, up to 1600, up to 13,000, epoxy values up to 3.6 eq/kg, and softening points between 80 and 160°C. Powder coatings formulated with carboxyterminated polyesters are hard, glossy, solvent-resistant but somewhat brittle. In order to overcome this drawback, polycycloacetals have been produced from TMCH and glutardialdehyde, which are terminated by pairs of methylol groups. Powder coatings of the corresponding glycidylethers with carboxyl-terminated polyesters exhibited excellent flexibility and impact strength.

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A Rhodium on carbon catalyst is used to hydrogenate epoxy compounds in order to selectively obtain saturated cycloaliphatic products leaving the epoxy groups almost untouched. This reaction works well when the catalyst is fresh but it fails to go to completion when the catalyst is used for the second time. A reactivation method was then seeked to get rid of this catalyst poisening. In order to assess the quality of the “cleaned” catalyst, we developped a fast method using the SEM-EDX combination to avoid the long way through the chemical reaction itself and the required analysis.We built sample holders to support the catalyst for analysis. It is a carbon stub with a calibrated cavity in the middle. The catalyst required for analysis is poured in the cavity and the excess is removed so that the surface obtained is flat and flush with the carbon stub itself. It is then loaded in the SEM and an EDX spectrum is acquired with preseted conditions.