GB1130323A - Process for preparing lactam polymers - Google Patents

Abstract

1,130,323. Poly-#-lactams. FARBWERKE HOECHST A.G. 7 Jan., 1966 [7 Jan., 1965], No. 869/66. Heading C3R. Poly-#-lactams are produced by adding the lactam dropwise to a solution or dispersion of a basic catalyst in an inert liquid. Suitable lactams are those which are unsubstituted in the N-position but may contain up to 4 substituents on the α- and #-carbon atoms, these substituents containing up to a total of 12 aliphatic carbon atoms or 1 aromatic group and up to 9 aliphatic carbon atoms. A divalent substituent may be present giving rise to a ring in the molecule. Specified lactams include 4-methyl azetidinone, 4-vinyl azetidinone, 3,3-dimethyl azetidinone and 4,4-dimethyl azetidinone. Basic catalysts specified include the potassium salt of α-pyrrolidone. Solvents or dispersing media for the catalyst specified include dimethyl sulphoxide, tetramethylene sulphone, phosphoric acid tris(dimethyl amide), dimethyl formamide and N-methyl pyrrolidone. An initiator may be added to the catalyst before or simultaneously with the addition of monomer. Initiators specified include oxalyl pyrrolidone. A chain terminator, e.g. water, may also be added. The rate of lactam addition may equal the rate of consumption and the polymerization temperature may be between -15‹ and + 120‹ C. In a particular embodiment of the invention the catalyst solution or dispersion is emulsified with a liquid with which it is only partially miscible. This liquid may, however, be completely miscible with the lactam. Suitable liquids are C 5-24 aliphatic or cycloaliphatic hydrocarbons, e.g. kerosene (b.p. 160-180‹ C.), aliphatic ethers having 1-3 ether oxygen atoms and 4-24 carbon atoms, e.g. isopropyl ether, araliphatic ethers having 1-3 ether oxygen atoms, 6-24 aliphatic carbon atoms and 1-3 phenyl radicals or araliphatic hydrocarbons having 1-3 phenyl radicals and 3-24 aliphatic carbon atoms, e.g. isododecyl benzene. The emulsion may be formed with the aid of an emulsifier, e.g. a sulphonamide of an ethylenepropylene copolymer of repeating unit a thickener or a protective colloid. In Examples (2-4) a small quantity of monomer is mixed with the catalyst before the solution is emulsified. In Example (2) polyisobutylene is present.