Verfahren zur Herstellung von sphaerischen Mikropartikeln auf Celluloseacetat bzw. Cellulose-Basis

The prodn. of spherical microparticles (I) based on cellulose acetate (CA) comprises: (a) making a halogenated hydrocarbon-free soln. of CA by mixing CA with at least 2 components (IIA/IIB) which are readily volatile at below 100 deg.C and immiscible or only slightly miscible with water, each of which by itself is a non-solvent for CA, (b) dispersing the soln. in aq. medium, (c) coagulating the resulting polymer particles by evapn. of solvent, and (d) sepg. from the medium. Also claimed is microparticle (I) made by the process mentioned above, with a particle size distribution of 0.1-100 mum and a porosity distribution of 5-95%. USE - The process is used for the prodn. of porous cellulose beads for use in chromatography and as a support for enzymes, cells and other ligands, e.g. after activation and coupling of proteins. ADVANTAGE - A simple and economical process for the prodn. of (I) with a narrow particle size distribution and variable porosity, using non-toxic and/or environmentall y harmless solvents instead of halogenated hydrocarbons, and without using high-mol. wt. pore-formers which require subsequent washing out with organic solvents. The process gives very uniform spherical particles with no deformation or sticking, which undergo simple hydrolysis with NaOH to give porous cellulose beads.