FIELD: packing and packing materials. SUBSTANCE: in making of packing cardboard and liquid-tight and gas-tight packages and articles polymericable reaction mixture is applied in uniform layer onto paper or thin or thick cardboard base. Proposed mixture contains at least one silicon compound forming inorganic polymer skeleton of chain type or that with cross-links containing alternative atoms of silicon and oxygen and at least one reaction organic compound forming organic side chains and/or cross-links relative to polymer skeleton. Reaction mixture can form colloidal solution in which gelatinization takes place simultaneously with polymerization. Gel, thus formed, is dried, compacted and solidified with formation of coating impermeable to liquids and gases. In addition to oxygen and silicon, above-indicated polymer skeleton of chain type or that with cross-links can contain silicon replacing metal atoms, and organic compound can contain, as reaction groups, epoxy, amino-, carboxylic, carbonyl, vinyl or methacrylic group. Moreover, cross-link forming polymer coating can be applied in uniform layer onto previously formed impermeable glass-like layer of coating to close-pre-made package. Packs for milk and juices and similar packs for liquid food products, bags for food products sealed by heat method and removable covers of containers and boxes and backing for microwave and conventional ovens made from paper and cardboard and coated as stated above are considered as liquid-tight and gas-tight articles. EFFECT: provision of impermeability for liquids and gases, and sufficient strength of containers made from thin or thick cardboard. 17 cl, 6 dwg, 4 tbl, 4 ex
