DYNAMICS OF CHANGE OF REQUIREMENTS OF STANDARDS TO DURABILITY OF WOOD-SHAVING PLATES: REASONS AND CONSEQUENCE

Abstract

Drevesno – chip plates are widely used in production of case furniture. The volume of their production constantly grows in Russia. If in 2013 it has been made 7270, then in 2017 – 8370, in 2018 – 9789, in 2019 – 9986 thousand m3 of plates. However, one of the main shortcomings of plates of the plates released by the industry is their low durability. It especially concerns one of the main strength performances of plates – ultimate strength at bend. So, in comparison with requirements of GOST 10632-77 durability of plates at bend of the most widespread thickness (13-20 mm) in accordance with GOST 10632-89 has decreased on 9 and 21, in accordance with GOST 10632-2007 on 21 and 29, and by current GOST 10632-2014 – by 38 and 43% depending on brand of plates. Decrease in durability at stretching perpendicular to plate face less noticeable. One of the main reasons of such decrease, use in technology of plates of low-toxic carboamidoformaldehyde (KFS) pitches the content of free formaldehyde in which generally is makes about 0,15%. It is known, than more free formaldehyde is in pitch of subjects bond quality of wood and wood-base materials, with use of this pitch, above. However such big decrease in durability of plates for furniture makers is big shortcoming. It is necessary to change approaches to designing of furniture from such plates. Manufacturers of plates, using low requirements of the present standard, sometimes manipulate due to decrease in density of plates that results in friability of plates, problem of fastening of plates in furniture designs. The purpose of our work was studying of dynamics of decrease in durability of plates according to requirements of standards, since 1977 till present, establishment of the reasons and possible consequences from such decrease.