FIELD: chemistry.
SUBSTANCE: invention relates to thermally solidificated covering substances based on aprotic solvents. Claimed is covering substance, which contains at least one compound (A), which contains hydroxyl groups, at least one compound (B) with free and/or blocked isocyanate groups, and at least one catalyst (D) for cross-linking silane groups, with one (i) or several components of covering substance containing hydrolysed silane groups and (ii) covering substance can be finally solidificated for covering, which has statistically distributed regions of lattice Si-O-Si. Obtained from covering substance solidificated coating has index of further cross-linking (PCI) lower than 2, with index of the further linking (PCI) being determined as coefficient from memory module E'(200) of finally solidificated coating, measured at 200°C, to minimum of memory module E'(min) of finally solidificated covering, measured at temperature higher than temperature of transition into glass-like state of Tg, and memory modules E'(200) and E'(min),as well as temperature of transition into glass-like state Tg are measured on free films with thickness of layer 40 mcm+/-10 mcm by means of dynamic mechanical thermal analysis (=DMTA) at rate of heating 2 K per minute and frequency 1 Hz and DMTA measurement on free films with thickness of layer 40 mcm+/-10 mcm, which are solidificated for 20 minutes at object temperature 140°C and after solidifying are kept for 8 days at 25°C, before carrying out DMTA measurements. Polyisocyanate (B) at least partially has one or several similar or different structural units of formula -X-Si-R"XG3-X, where G = identical or different hydrolysed groups, in particular alcoxy group, X=organic residue with from 1 to 20 carbon atoms, R" =alkyl, cycloalkyl, aryl or aralkyl, and carbon chain can be broken by non-adjacent oxygen groups, sulphur or NRa, with Ra=alkyl, cycloalkyl, aryl or aralkyl, x=0 to 2. Catalyst (D) is phosphorus-containing, and covering substance contains catalyst (D) from 0.1 to 10 wt % in terms of non-volatile components of covering substance. 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 atmospheric impact.
18 cl, 4 tbl, 7 ex
