Ketone resin ageing

Ketonic resins (Laropal K 80 , MS2A) -1930 Varnishes Seed oils Quite stable with ageing with a low tendency to yellowing... 

Domenech-Carbo, M. T., Bitossi, G., Osete-Cortina, L., Yusa-Marco, D. J. (2009). Study of ageing of ketone resins used as picture varnishes by pyrolysis-silylation-gas chromatogra[4iy-mass spectrometry. Journal of Analytical and Applied Pyrolysis, S5( 1), 470-479. 

Domenech-Carbo MT, Aura-Castro E, Mas-Barbera J, Martinez-Bazan ML (2006) Evaluation of morphological changes of aged acrylic, ketone and hidrocarbon resins used in contemporary artworks. Arche 1 163-166. 

A series of Vap GC analyses on approximately 50 mg of all the aged resin samples was conducted. Ethanal, propanal, isobutyraldehyde, propenal, butenal, methyl ethyl ketone (MEK), and methyl penetenal were positively identified by mass spectrometry. With the exception of MEK, all compounds identified (the major products) were aldehydes. Methyl ethyl ketone, the solvent used in MY720, remains even after cure. The aldehydes, however, are not impurities in either the MY720 or DOS and represent compounds which are characteristic of the resin alone. These compounds are either produced during the curing process or are formed from the thermal decompositon of a labile compound which is formed during cure. 

Ester and ketone solvents, which react with amines, must not be present. The adduct is a polyamine and can therefore be used to crosslink epoxy resins. It has advantages in that it is odourless (simple amines are unpleasant to handle), part-reacted (which speeds up drying) and free from simple amines (which cause exudation). It can be seen now why it is an advantage to age paints cured by simple amines amine adducts are formed during the ageing. 

Solvents, or solvents containing small amounts of hodying resin, are used for bonding thermoplastic resins and film adhesives. An example is toluol, which can he used to soften and dissolve polystyrene molded articles to allow joining the softened pieces. Ketones can be used to bond PVC films in a similar manner. A small amount of resin can be used to thicken the solvent so that a sufficient amount would stay in place to dissolve the substrate. It should be noted, however, that solvent welding of molded plastics can cause stress cracking and weakening of the structure as the parts age. ... 

But, the greatest growth of BPA production started at the beginnings of the Age of Plastic in the 1950s. At that time, industrial fabrication of polycarbonates and epoxy resins started [12], and Bisphenol-A became the primary monomer for their synthesis. As a difunctional monomer, later on BPA became one of the most important raw material used for synthesis of other polymers as well as polymer additives. Now, BPA is also used in the production of polyesters, polysulphones and polyether ketones. Its use for formulation and preparation of polymer additives (e.g., antioxidants, plasticizers, polymerization inhibitors and halogenated flame retardants) is still its another important application. 

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