METHOD OF MAKING PREPREG Russian patent published in 2013 - IPC B29B15/10 B29B15/12 C08J5/24 

FIELD: process engineering.

SUBSTANCE: invention relates to method of making prepreg used in production of multilayer polymer composites for aerospace engineering, car and ship building, etc, wherein heat protection materials with high heat resistance properties. Proposed method comprises placing workpiece into sealed container, evacuation of sealed container with workpiece, reiterated impregnation of workpiece in vacuum with polymer binder with subsequent reiterated drying. Pre-impregnation is performed before evacuation by dipping siliceous or siliceous-kapron workpiece in binder based on phenol-formaldehyde resin with content of solvent making 50-60 wt %. Note here that pre-impregnation and impregnation in vacuum are carried in fractions with total amount equal to design amount of binder while reiterated drying is performed at vacuum at P=0.08-0.1 MPa after every impregnation with exposure at t=25±10°C for 2-2.5 hours while final drying is performed at overpressure P=0.25-0.3 MPa with exposure at t=25±10°C for 12-13 h.

EFFECT: high mechanical strength and heat resistance of polymer composite operated at high temperatures and mechanical loads.

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