Infra red heating speeds Scottish paper plant

Johnstone, UK – Smith & Mclaurin Ltd has more than doubled the line speed on one of its paper coating lines and improved quality following the retrofit installation of a carbon infra-red heating system at its Renfrewshire plant in Scotland.

The Johnstone-based company supplies self-adhesive material in roll form to printers and converters who produce finished label ticket and tag products for end users, including, supermarkets, pharmacy chains and food manufacturers.

A particular product finds application where security is important, such as in labels and security envelopes. This product requires a water-based adhesive to be applied to a high value stock before a laminate is applied to the adhesive. In some cases, the laminated product is re-passed through the adhesive station so that the laminated layer itself carries a layer of surface adhesive.

Previously, the adhesive was dried in a warm-air oven but this sometimes caused problems when drying coloured adhesives, with “spotting” or reticulation, which created an uneven and visible adhesive pattern on the substrate. As a result it was necessary to slow down the line to around 20m/min.

To solve the problem, Smith & McLaurin contacted Heraeus Noblelight, which supplied a portable infra-red module to allow tests to be carried out on site.

The tests proved successful and a 32.5kW, system equipped with five carbon medium wave emitters was installed immediately before the existing warm air heaters. The emitters are individually controlled so that they can be switched on and off according to the coating weight.

“By using the infra-red heaters to direct an initial burst of energy at the wet adhesive we have been able to eliminate any “spotting,” Iain McCourty, engineering manager at the Renfrewshire site.

“This has meant that we have been able more than double line speed. It has also meant that we have been able to guarantee quality which has helped to consolidate our relationships with customers.”