METHOD FOR PRODUCING BLOCK PRODUCTS FROM NON-FUSIBLE POLYIMIDES CONSISTING OF WASTE PRODUCTS OF POLYPYROMELLITIMIDE FILMS Russian patent published in 2017 - IPC B29B17/00 

FIELD: chemistry.

SUBSTANCE: invention relates to the production of heat resistant press materials based on powdered polypyromellitimides, and can be used to produce block products for continuous operation at elevated temperatures (up to 300°C) and extreme environmental conditions. The invention allows to obtain strong products from non-fusible polyimides up to 90 wt %, consisting of a waste of polypyromellitimide PMDA-DADPE film, due to the fact that mechanoactivational processing of PMDA-DADPE films is carried out in a ball planetary mill at a rotation speed of 425-460 rpm for 45-55 min. A joint mechanoactivational processing of the obtained PMDA-DADPE powder waste with the industrial polyimide powder BFDA-DADPE of PI-PR-20 grade and polyimide resin SP-97C is carried out in a ball planetary mill at a rotation speed of 425-460 rpm for 22-40 min. The powders are dried at 270-285°C for 30-40 minutes. Air sintering of the obtained powder mixtures is carried out at 380-400°C at a pressure of 80-100 MPa for 25-40 minutes.

EFFECT: improved physical and mechanical properties of products.

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