STUDY ON THE GRINDING TIME DURATION IMPACT ON

Both raw and recycled fiber materials are used for paper production. The increase in percentage use of the latter is due to their paper-forming properties, availability and low cost. The article explores the possibility of using pulp from the inner layer of mulberry twig bark. Mulberry twigs, after removing leaves, which are the main raw material in silk production, have no practical industrial application. Recycling waste - mulberry branches - for the production of pulp is therefore relevant as it is aimed at solving raw material and environmental problems. The purpose of this work is to use local raw materials for paper production, study the impact of processing method of the grinding process on paper forming properties. During grinding the mechanical processes of changes of fibers determine mainly structure of a paper sheet, and colloidal-physical processes - bind and ability of fibers to form strong, homogenous and smooth structure of paper. The structure of the sheet of paper facilitates excessive or "selective" ink absorption into the pores of the paper and thus predetermines the quality of reproduction during the printing process.  Methods for determining the physical and mechanical properties of papers were used in this work, and changes in the surface structure of samples cast at various technological modes of the milling process were studied. The results of the study revealed that the addition of cellulose mass from the inner layer of mulberry twig bark helps to obtain a strong paper. The optical properties of the paper, which contains cotton and cellulose from the inner layer of mulberry branch bark, are explained by the whiteness of the added fibers themselves. The strength properties of the paper at a weight grinding degree of 300 CWR are explained by the bond between the split and strongly interwoven fibers of the cellulose fibers. It has been established that the addition of more than 30% cellulose from the inner layer of the mulberry branch bark to the paper pulp mass is undesirable, as this adversely affects the whiteness of the paper.