Clean air technologies: Modern approaches to reducing the toxicity of wood slab materials

\nThe purpose of the work was to study and analyze existing methods for reducing the toxicity of wood slab materials. The requirements for the release of free formaldehyde from plywood of chipboard and other types of boards are constantly being tightened, since this toxicant is a strong carcinogen and can contribute to the development of a number of diseases in humans. Therefore, obtaining environmentally friendly wood slab materials in the process of their manufacture and operation, in order to prevent various human diseases, is an urgent problem. The paper presents the results of experimental studies on the development of formulations of adhesives based on urea-formaldehyde resins for gluing plywood and plywood products containing a filler that can simultaneously act as a formaldehyde acceptor and glue hardener. Waste from woodworking industries – oak bark flour, birch bast flour and wood flour are recommended as fillers. In order to increase their adsorption capacity, a rational mode of acid modification of these fillers has been established (activating agent – 12% solution of orthophosphoric acid, processing time 6-8 hours, processing temperature 800C). Acid activation of the selected fillers in the established mode allowed to increase their adsorption capacity for formaldehyde by about 80%. The introduction of acid-treated vegetable fillers into the CFS in the amount of 2-3 wt. h. per 100 wt. h. of resin allowed to reduce the content of free formaldehyde in liquid glue by 6-12 times. The use of these adhesive compositions allows you to completely eliminate the expensive hardener from the glue formulation when gluing plywood.\n