Wood working12.02.2016

Building a strong bond through good collaboration

Koskisen’s Anna-Maaret Roppola gives Sari Hartikainen and Tomi Hirvonen of glue supplier Prefere a tour of the mill.

Koskisen’s Anna-Maaret Roppola gives Sari Hartikainen and Tomi Hirvonen of glue supplier Prefere a tour of the mill.

Plywood manufacturing constantly relies on the expertise of the glue supplier; at its best, collaboration with the glue supplier can help boost production and improve the product. Prefere Resins Finland, which supplies Koskisen’s plywood mill with glue, has met this challenge head-on, and to reinforce the partnership between the two companies, a large number of Prefere staff visited the plywood mill in Järvelä last autumn to learn more about its operations.

Glue is used to bind veneer sheets, which have been peeled from logs, together into plywood. There’s no doubt that the glue supplier must have a strong knowledge of chemistry.

“We work together to continuously develop the glue’s utilisation window, meaning we fine-tune the recipe, the amount of glue required and the process times,” says Prefere’s Customer Service Manager Tomi Hirvonen, elaborating on the company’s co-operation with Koskisen.

Prefere employees visited Koskisen in autumn 2015.

Prefere employees visited Koskisen in autumn 2015.

Glue for interior and exterior use

Prefere supplies Koskisen’s plywood mill with both interior and exterior glues. Exterior or brown glue is weatherproof and suitable for plywood used outdoors, whereas interior glue, a nearly transparent, white glue, is well-suited to plywood used indoors, as the colour of the glued seam does not show in decorative products.

The properties and performance of both types of glue in mill conditions require continuous monitoring and fine-tuning, e.g. due to seasonal weather variations.

The viscosity, or flow, of the glue is measured using a Ford cup.

The viscosity, or flow, of the glue is measured using a Ford cup.

“On my almost monthly control visits we take a look at the viscosity of the glue, the processing times, quality-related matters and the actual deliveries of resins and hardeners,” says Hirvonen.

“With a fresh set of eyes it is possible to detect deviations, often even very minor ones, which means we can take corrective measures before any damage occurs.”

Curtain-coating method the latest trend

The world of glue manufacturing is evolving at a fast pace. Among the latest developments is glue-spreading machines based on curtain coaters. In the Finnish plywood industry, glue is traditionally spread with rollers.

“Using the new curtain-coater method, the amount of glue used per cubic metre of plywood can be reduced, and the glue is spread more evenly. This helps keep production costs under control,” says Anna-Maaret Roppola, purchasing manager for Koskisen’s Plywood business unit.