Patent GB-1165729-A (GB)
Title: Modified Polyamides and a process for preparing the same
IPC: D06M14/16
Filed: 1966-09-29
Abstract: 1,165,729. Polyamide after - treatment. SCOTT PAPER CO. 29 Sept., 1966 [29 Sept., 1965; 6 July, 1966], No. 43657/66. Headings C3G and C3R. Polyamides are made capable of accepting addition polymer grafts by treatment in alkaline solution with a compound of formula CX 2 , where X is a chalcogen, at least one X per molecule being sulphur, M is H, alkali metal, ammonium or an organic ammonium, phosphonium or sulphonium radical, R is alkyl or one of the radicals specified for M and R<SP>1</SP> is H or alkyl. The alkyl groups may contain 1 to 6 carbon atoms. The polyamide may be derived from an aminocarboxylic acid, e.g. nylon 6, or a diamine and a dicarboxylic acid, e.g. nylon 66. It may have a M.W. of about 10,000 and be in fibrous form. It may be exposed to CS 2  or COS vapour or immersed in an aqueous solution, emulsion or suspension containing an alkali metal mono-, di- or trithiocarbonate, e.g. 0.5% to a saturating amount of sodium trithiocarbonate, 1-10% of an alkali metal, ammonium or alkyl dithiocarbonate, a half ester of thiocarbonic acid, or a thiocarbonic acid or salt. Alternatively it may be treated with 0.1 to 15% alkali and then exposed to gaseous CS 2  to COS. The aqueous solvent may contain 10-100% water. The treatment may be at 0-60‹ C. Sulphur containing reactants specified include CS 2,  COS, CS 2 /NaOH, EtKCOS 2,  Na 2 COS 2,  NaHCOS 2,  K 2 COS 2,  Na 2 CS 3,  (NH 4 ) 2 CS 3,  EtNH 2 /CS 2,  diethanolamine/CS 2  and triethanolamine/CS 2 . A surface active agent may be present, e.g. polyethylene lauryl ether, polyoxyethylene sorbitan trioleate or sorbitan mono-oleate. In Example 21 the disodium salt of ethylene diamine tetraacetic acid is also present. The treated polyamide may be further reacted to replace the alkali metal ions present by another metal; e.g. iron may be introduced by reaction with Fe 2 (NH 4 ) 2 (SO 4 ) 3 . The treated polyamide may be washed before grafting an ethylenically unsaturated monomer on to it by a peroxide catalysed reaction. The ethylenically unsaturated monomer may be acrolein, vinylidene chloride, vinyl methyl ether, vinyl ethyl ether or divinyl sulphone, a compound of formula CH 2 =CHR 2 , where R 2  is aryl or a compound of formula CH 2  = CR 1 R 2 , where R 1  is H, Me or Et and R 2  is CN, COOR 3 , CONR 4 R 5 , OCOR 6 , halogen or a heterocyclic group, R 3  is H or alkyl, R 4  and R 5  are H, alkyl or substituted alkyl and R 6  is H, saturated or unsaturated alkyl. Such compounds specified include acrylamide, acrylic acid, ethylacrylate, acrylonitrile, styrene, 2-ethylhexyl acrylate, stearyl methacrylate, vinyl acetate, 2-chloroethyl acrylate, glycidyl acrylate, vinyl toluene, ethyl methacrylate, methyl methacrylate, N-vinyl pyrrolidone, hydroxypropyl acrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate and N,N - dimethylaminoethyl methacrylate. These may be supplemented by maleic acid, fumaric acid, dimethyl maleate, dibutyl maleate, dimethyl fumarate, dibutyl fumarate, maleic anhydride, diallyl fumarate, diethyl fumarate, itaconic acid, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate or tbutylaminoethyl acrylate. The vinyl monomer may be in the form of a 1-90% solution, emulsion or dispersion in an aqueous liquid containing 10-100% water. This may also contain a surfactant, and a pH 1-6 buffer. 0À05%- 95% of polyamide may be used. The reaction may be at 0-100‹ C. at subatmospheric or superatmospheric pressure. An inert atmosphere is not essential. In examples peroxides specified are H 2 0 2 , performic acid, ammonium persulphate and tertiary butyl hydroperoxide. In Example 21 phosphoric acid is present and the polymer graft which contains acrylonitrile units is hydrolysed with NaOH so that sodium acrylate units are formed. These are converted to magnesium acrylate units by MgCl 2 . Alternatively the sodium acrylate units may be converted to acrylic acid units by acetic acid and then to metal salt units or organic ammonium salt units. In Examples 23 and 24 the reaction liquids are kept in motion by passing them round an external circuit and returning them to the reaction vessel.