| 摘要 |
Vitreous substrates such as lead glass or crystal glass are coated with a layer of silica SiO2 using a chemical vapour phase deposition technique employing a silane coating agent (I) which is converted into silica by thermal decomposition, the process comprising (a) heating the substrate to a temp. of less than or equal to its glass transition temp. and sufficient to cause thermal decomposition of the silane into silica and (b) contacting the (I), at least partially in vapour form, with the surface of the substrate to be coated in the presence of oxygen such that the (I) decomposes, at least partially, to produce silica which becomes attached to the surface in the form of a film, characterised in that in the vapour phase the ratio oxygen/silane (expressed in moles) is controlled at between 3-10, pref. 5-9 and esp. 6-7. USE/ADVANTAGE - The process is esp. useful for coating the interior surface of bottles, flasks, ampoules, etc., used for packaging liq. food prods., drinks such as brandy, whisky, wine, fruit juice, etc., pastes such as mustard, and liq. pharmaceutical prods. Deposition of the silica film provides the substrate glass with improved mechanical, aesthetic and optical properties and esp. acts as a barrier layer which prevents migration of noxious agents such as alkali metals (Na), alkaline earth metals (Ca) and heavy metals (Pb) from the body of the glass into liqs. contained in vessels made from the glass.
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