The results of microscopic studies of the homogeneity of premix compositions from a mixture of epoxy resin and APS-94 hardener, differing in the method of dispersing the hardener, are presented. Rheological and mechanical tests of VSK-14-1 adhesive binders made using premixes of various homogeneities, were carried out, and the rheokinetics of curing of KMKS adhesive prepregs based on the above mentioned binders was studied. It has been established that the appearance of inclusions in the form of white spots in KMKS prepregs is associated with the presence in the premix of undissolved particles of the APS-94 hardener with a dispersion of 100 to 300 microns. A criterion for the degree of homogeneity of the premix was experimentally determined, ensuring the production of high-quality adhesive binder and prepreg based on it: the dispersion of particles of the APS-94 hardener should not exceed 80 microns.