Лако-красочные материалы — производство

Manfred Dunky

Dynea Austria GmbH, Krems, Austria

I. INTRODUCTION

Progress in research and development within the wood-based industry and within the adhesive industry has shown many successes during the past few decades. Notwithstanding this, the industrial requirements of the wood industry still induce technical improvement in the adhesives and their application in this area. What drives this technical development is the search for ‘‘cheaper,’’ ‘‘faster-curing,’’ and ‘‘more com­plex’’ adhesives. The first two requirements are caused by the heightened competition within the wood industry and efforts to minimize costs at a certain level of product quality and performance. The requirement ‘‘more complex’’ stands for new and specialized products and process. Adhesives play a central role within wood-based panels production. The quality of bonding and hence the properties of the wood-based panels are determined mainly by the type and quality of the adhesives. Development in wood-based panels, therefore, is always linked to development in adhesives and resins.

Both the wood-based panels industry and the adhesive industry shown a high com­mitment to and great capability towards innovation. The best evidence for this is the considerable diversity of types of adhesives used for the production of wood-based panels. Well known basic chemicals have been used for a long time for the production of adhesives and their resins, the most important ones being formaldehyde, urea, mela­mine, phenol, resorcinol, and isocyanate. The greater part of the adhesive resins and adhesives currently used for wood-based panels is produced with these few raw materials. The ‘‘how to cook the resins’’ and the ‘‘how to formulate the adhesive’’ therefore become more and more complicated and sophisticated and are key factors to meet today’s require­ments of the wood-based panels industry.

The quality of bonding and hence the properties and performance of the wood-based panels and beams are determined by three main parameters:

the wood, especially the wood surface, including the interface between the wood surface and the bondline the applied adhesive

the working conditions and process parameters.

Good quality bonding and adequate properties of the wood-based panels can be attained only if each of these three parameters contributes to the necessary extent to the bonding and production process.

In this chapter are then covered the types of adhesives used in the wood industry and their characteristics. The influences on their performance of the adhesives’ physicochem­ical characteristics, of their application parameters, of the wood itself, and of the wood composite process parameters are also described. In wood adhesives the application par­ameters other than the characteristics of the adhesive itself account for around 50% of performance.