EFFICIENCY EVALUATION OF UREA FORMALDEHYDE RESIN MODIFIED WITH OLEIC ACID IN WOOD PANEL INDUSTRY

Abstract

Introduction. From the position of resource efficiency, it is deemed a prospective direction in economy of timber products and cost reduction to expand the raw material base and to include non-timber fillers into production. Such fillers as, for example, flax board  allows to diminish material consumption  and to produce quality construction panels with the properties similar to  wood particle bases, but at reduced cost. Resinfication of a flax board and other non-timber fillers with synthetic adhesive agents is carried out in an uneven manner. Bearing in mind the theory of adhesion and humidification it is necessary to reduce the surface tension of adhesive agent in order to attain quality resinfication of a flax board using, for example, modifying additives based on unsaturated fatty acids.  The work is aimed at efficiency evaluation of urea formaldehyde resin modified using oleic acid in the production of flax containing boards. The work tackles the following objectives: experimental evaluation of humidification capacity of adhesive agents based on urea formaldehyde resin, modified oleic acid and calculation of gluing capacity of modified adhesive compounds. During experimental research the surface tension of the adhesive compounds under study was defined by pin pull test method, and a contact angle of wetting a wooden particle surface with adhesive compounds was carried out by sessile drop method. Physical and mechanical characteristics of boards were assessed using standard procedures. Experimental results proved that modification of urea formaldehyde resin with oleic acid reduces surface tension, which has a positive effect on the humidification process of a flax board. The surface of flax board particles is completely humidified provided the adhesive compound based on urea formaldehyde resin contains 1.25 – 1.75 pts. wt. of oleic acid. The work defines the impact of surface tension of a modified adhesive compound on the gluing capacity, and also estimates the maximum adhesion work. The analysis of the obtained experimental data proved that once the adhesive compound based on urea formaldehyde resin is complemented with oleic acid, the physical –mechanical characteristics of flax boards are considerably enhanced, thus complied with the GOST 10632-2014 standard requirements. Conclusion. Modification of urea formaldehyde resin with oleic acid enables reduction of the surface tension of the adhesive agent to the level of substrate used to produce panels. Introducing this modifier provides for the enhanced physical and mechanical characteristics of a panel alongside operating and production safety of adhesive compound.