Interlayer material for separating stored glass sheets - comprises finely-divided PVC, PMMA etc., buffered to pH 1-6 with a suitable buffer system contg. an indicator, esp. phenolphthalein

摘要

An interlayer material (I) for stacking, transport and storage of plate glass is claimed, based on finely divided organic maerial such as PVC, polystyrene, PMMA or wood flour (II); the novelty is that (II) is combined with a buffer system so that the aq. phase of a slurry of (II) in water has pH 1.0-6.0, and contains an indicator (III) for which the lower limit of the colour change interval is below pH 9.0. More specifically (II) is PVC powder obtd. by suspension polymerisation, with mean particle size 0.03-1 mm and directional factor (RRS lines) above 2.5; a Sorensen-Clark buffer system is used, with phenolphthalein as indicator (III). USE/ADVANTAGE - (I) is useful as an interlayer material to prevent glass sheets sticking together in the above situations. The invention provides an interlayer material which gives long-term protection from mechanical damage and alkaline corrosion, and indicates the critical phase of progressive corrosion; the material is easy to handle and to remove from the glass as require