Aeci Limited

Richard B Le Maitre

Vaughan P Goddard

A hot knife coater comprises a pair of thicknesser blades defining between them a thicknesser gap through which a web to be coated passes. Each blade is connected to a downwardly depending mid-portion of a blade support by means of a number of longitudinally spaced blade holders. This minimizes bowing of the blade supports as a result of heat conducted to the blade supports from the respective blades. The blade holders connecting one of the blades to the respective blade support are adjustable so as to permit local adjustment, in the region of each blade holder, of the gap. Each blade support is mounted so as to be pivotal about a longitudinally extending pivot axis and is biased by a spring against a stop. This permits automatic opening of the gap to let a seam in the web through the gap, thus eliminating the need for operator intervention.

Coating apparatus

A method of producing sheet material comprises heating a web 10 of closely woven fabric to a temperature of at least 50.degree. C., and preferably to about 150.degree. C., and then impregnating the hot fabric with polyvinylchloride (PVC) paste containing a bonding agent, thereby to provide a material in which the fabric is coated with PVC on each side thereof. Impregnation takes place in a bath 14 with pinch rollers 16 through which the web passes. The pinch rollers 16 squeeze surplus PVC from the web and enhance impregnation. Thereafter the coating can be built up to the desired thickness by dip-coating (in a bath 18) or by a lamination process, whereafter the coated web is cooled in cooling rollers 34 and wound up by a wind-up device 36.

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Somerset West, South Africa

Richard B Le Maitre