PROCESS FOR PRODUCING FILM-FORMING AGENT Russian patent published in 1995 - IPC

FIELD: preparation of a film-forming agent. SUBSTANCE: a film-forming agent is prepared by mixing an oxidized solution of butyl rubber (calculated by dry matter, sunflower oil and an additive in a 1:0.5:1.5 ratio, respectively. The resulting mixture is oxidized with air at 95-105 C at an air flow rate of 2,1-2,5 m³/min·t for 1.5-3.0 hr. The additive is selected from the following group of compounds: diene polymer, terpene polymer and terpene oil. The additives contain 51-94 wt % dry matter. An oxidized solution of butyl rubber is prepared in stages by introducing butyl rubber in equal portions to the stages. In the first stage the natural rubber to solvent weight ratio is 1:4.33-4.63. The stage is carried out at 89-105 C in the presence of 1.0-1.05 wt % per initial portion of the manganese siccative rubber. The air flow rate for oxidation at the initial period is 0,15-1,0 m³/min·t.) The air-flow rate for the first portion of rubber is increased to 1,1 - 2,0 m³/min·t. and the process is carried out till the/oxidized solution of rubber at the first and intermediate stages has a viscosity is 30-73 cst as measured by a viscosimeter. At the 2nd and subsequent stages the initial air flow rate is 0.65-2.0 m³/min·t and the air flow rate is then increased to 1,5-2,0 m³/min·t.. The process is carried out at 95-105 C till the dry residue reaches 32.4-45% and the final oxidized rubber solution has a viscosity of 45-90 cst as measured by a viscosimeter. The increased air flow rate at the butyl rubber oxidation stages is effected when the added portion of rubber substantially completely passes in solution. EFFECT: enhanced efficiency. 2 cl, 2 dwg, 2 tbl