FIELD: chemistry.
SUBSTANCE: invention relates to thermally solidificated covering substances based on aprotic solvent. Claimed is covering substance, which contains at least one compound (A), containing hydroxyl groups, at least one compound (B), containing isocyanate groups, and at least one phosphorus-containing catalyst (D) for cross-linking silane groups, with one or several components of covering substance containing between 2.5 and 97.5 mole %, counted for totality of structural units -N(X-SiR"x(OR')3-x)n(X'-SiR"y(OR')3-y)m (II) and -Z-(X-SiR"x(OR')3-x) (III), at least one structural unit of formula (II), where R'=hydrogen, alkyl or cycloalkyl, carbon chain can be interrupted by means of non-adjacent groups of oxygen, sulphur or NRa, with Ra= alkyl, cycloalkyl, aryl or aralkyl, X,X'=linear and/or branched alkylene pr cycloalkylene residue with from 1 to 20 carbon atoms, R" =alkyl, cycloalkyl, aryl or aralkyl, and carbon chain can be interrupted by means of non-adjacent groups of oxygen, sulphur or NRa, with Ra= alkyl, cycloalkyl, aryl or aralkyl, preferably R"=alkyl residue, n=0 to 2, m=0 to 2, m+n=2, x,y=0 to 2; and between 2.5 and 97.5 mole %, counted per totality of structural units (II) and (III), at least one structural unit of formula (III), where Z=-NH-, -NR-, -O-, R=alkyl, cycloalkyl, aryl or aralkyl, and carbon chain can be interrupted by means of non-adjacent groups of oxygen, sulphur or NRa, with Ra= alkyl, cycloalkyl, aryl or aralkyl, x=0 to 2, and X, R', R" have value, given above, and covering substance can be finally solidificated before covering, which has statistically distributed regions of lattice Si-O-Si. Also claimed are multi-step method of applying coating with application of claimed covering substance, as well as application of claimed method and versions of claimed coating application.
EFFECT: possibility to obtain transparent varnish coating with high resistance to formation of cracks under atmospheric impact and perfect resistance to scratching.
18 cl, 4 tbl, 7 ex
