METHOD OF PRODUCING CARBON NONWOVEN MATERIAL Russian patent published in 2016 - IPC D04H1/425 

FIELD: chemistry.

SUBSTANCE: invention relates to production of carbon nonwoven materials, including for use as material for making gas-diffusion cathodes for chemical current sources. Method of producing carbon non-woven material, involving formation of three-layer nonwoven material consisting of two needle-felt outer layers and inner carcass layer, followed by needling, then, obtained via carbonisation of non-woven material in nitrogen medium at gradual increase of temperature to 600-700 °C and further graphitisation at temperature of 1,500-2,500 °C, formation of three-layer non-woven material is performed by displacement of needle-felt two external layers with different number of punctures in ratio 1:2 with surface density of one layer of 72-150 g/m² and number of punctures 6-18 at 1 cm² and surface density of 45-120 g/m² and number of punctures 12-36 at 1 cm² for another layer made from viscose stapled fibres with length of not less than 51 mm relative to each other by 1.5-2 mm, and carcass layer with surface density of 80-150 g/m², consisting of thin fabric formed by linen woven of polyoxadiazole threads at angle of 90 degrees with linear density of 24-39 Tex, with cell size from 1×1 to 4×4 mm, needle punctured to produce non-woven material with bulk density of 71-108 kg/m³.

EFFECT: technical result is improvement of manufacture ability of process by avoiding stage of additional orientation of carcass layer due to reinforcement of outer layers of nonwoven materials from stapled fibres with sparse fabric formed by linen woven of polyoxadiazole threads, with simultaneous increase in strength throughout volume of produced graphite nonwoven materials due to introduction of thin fabric, reduction of electric resistance and maintaining air permeability by forming channels with complex curved shape, which together with through channels form porous structure with the possibility to adjust air permeability, and control of gas supply into reaction zone due to micro sliding of layers relative to each other during operation of gas-diffusion cathodes of chemical current sources.

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