Flexible "Glass
Page 52
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The Remarkable Product of a French Scientist
Details of the Manufacture and Composition of a Synthetic Substance that can be Employed for the Windows of Motor Vehicles
AFRENCH invention described by our associated journal, The Motor, may possibly be of service to the commercial-vehicle industry, particularly in connection with public passenger vehicles. This is a synthetic, flexible substance with a high degree of transparency and refractive qualities superior to those of glass.
Similex, as the new material is termed, is the invention of a French scientist, Dr. Pechin. It is a phenol-formaldehyde compound in which is no area, the• latter having given rise to various troubles in former attempts to produce synthetic, flexible "glass." Similex is claimed to be weather-proof, acid-proof, fire-proof and sea-waterproof.
It is a non-conductor of heat, and is an excellent electrical insulator for highand low tension.
Similex has only just emerged from the experimental stage after many years of work and, whilst the samples which we have examined show room for improvement in the matter of colour and surface hardness, it would appear already to offer many advantages as a tough, flexible substitute for glass, being non-splintering and guaranteed to retain its transParency for an indefinite period.
Similex is one-third of the weight of plate glass and can be produced commercially at about the same price. Apart from its utility in constructing nonsplintering windows, the material, which is made in all varietiev of colour, may be employed in connection with internallighting schemes.
Similar material, under the name of Similac, may be used for weather-proofing and fire-proofing wood, etc. Any pigment that is covered with Similac is stated to retain its colour indefinitely.
Our Paris correspondent was allowed to visit Dr. Pechin's experimental laboratories at Asnieres, near Paris, and watch the process of manufacturing synthetic " glass." The simplicity of the plant employed was particularly noted as indicating cheapness in manufacture.
A mixture of phenol and formol is boiled in retorts and condensed in the presence of a catalytic agent, the resulting product being a dull, brownish resinous substance. This is placed in a clearing vat/ and a powerful clearing agent is added ; this makes the material colourless, the clearing process being conducted under vacuum.
The Similex is then ready for moulding. It is poured into moulds which will give it suitable shapes to take any subsequent mechanical finish that may be desired.
The moulds are next immersed in oil at a temperature of 150 degrees C. The lids of the oil containers are hermetically sealed and the containers are then put
• into communication with a powerful vacuum pump. The moulds remain in the oil bath, under vacuum, for several hours, when the process is complete.
One important result of the manufacture under vacuum is the elimination of bubbles from the material and, with them, of any free phenol or acid content remaining in the Similex product. The completed material may be drilled, sawn„ turned, polished and treated in any desired way, as it is heat-resisting and will not turn colour during these operations:
A company has been formed in France for the production of Similex in bulk, and tlae,chemists are at present tackling the problem of surface hardness. At present the material is quite suited to side windows, etc., but the surface is scarcely hard enough for windscreens.