FOERFARANDE FOER FRAMSTAELLNING AV VATTENLOESLIGA AKRYLPOLYMERER.

摘要

A process for preparing particulate water-soluble acrylic polymers, e.g. acrylamide or methacrylamide polymers and cationic acrylic polymers, having a high molecular weight, an excellent water solubility and a uniform particle size with a good productivity, which comprises: (a) adding at least one surfactant selected from the group consisting of a non-ionic surfactant and an anionic surfactant to an at least 20% by weight aqueous solution of a vinyl monomer in an amount of 0.001 to 1% by weight based on the monomer. (b) adjusting the dissolved oxygen in the aqueous monomer solution to at most 1 mg/liter, (c) admixing the aqueous monomer solution with at most 0.03% by weight of a photopolymerization initiator based on the monomer, (d) continuously feeding the aqueous monomer solution in the form of a layer having a thickness of 3 to 10 mm onto a moving support located in an atmosphere containing at most 1% by volume of oxygen, (e) irradiating the layer of the aqueous monomer solution on the moving support with ultraviolet rays having a wavelength of 300 to 450 millimicrons at an intensity of at most 50 W/m2, (f) continuously taking out the produced polymer in the form of a sheet having a thickness of 3 to 10 mm from the moving support, (g) breaking the polymer sheet to cubic pieces of 3 to 10 mm in length of a side by a roller type cutter, (h) pulverizing the cubic pieces to particles having a diameter of 0.3 to 3 mm by a vertical type cutter, and (i) drying the particles with hot air.