Patent GB-597326-A (GB)
Title: Treatment of polymeric materials
IPC: C08G69/50
Filed: 1941-11-27
Abstract: The properties of synthetic linear polyamides are modified by mixing the polyamide with a formaldehyde-liberating substance, not in preponderating amount, and then heating said mixture whilst or after forming it into shaped articles.  It is preferred to include in the mixture an acid, an acid anhydride or an acid-reacting salt, or there may be included a material which is neutral and remains so during mixing, but which develops acidity on heating. Specified formaldehyde-liberating substances are paraformaldehyde, trioxane, dimethylolurea, trimethylolmelamine, hexamethylolmelamine, diphenylolpropane tetraalcohol, methylolchloracetamide, methylol stearamide, N-methylol-p-toluenesulphonamide, dimethylolurea dimethyl ether, dimethylolurea dibutyl ether, N : N1-dimethyloluron dimethyl ether, 1 : 2-glycol methylene ether, di-(b -hydroxy-ethyl) formal and hexamethylenetetramine-zinc chloride complexes.  Specified acid substances which may be added, are formic, glycollic, oxalic, succinic, maleic, stearic, adipic, tartaric, salicylic, anthranilic, phthalic, citric, tannic, boric and phosphoric acids, phthalic and maleic anhydrides, phthalimide, and ammonium, potassium and sodium dihydrogen phosphate.  Specified neutral materials developing acidity on heating are butadiene sulphone, 2 : 3-dimethylbutadiene sulphone, butadiene tetrabromide, styrene dibromide, acetylene tetrabromide, tribromohydroquinone, 1-bromo-2-naphthol, 1 : 6-dibromo-2-naphthol, 1 : 4 : 6-tribromo-2-naphthol, 2 : 4-dibromo-1-naphthol, methyl a  : b -dibromopropionate, b -chloroethyl a  : b -dibromoisobutyrate, ethyl a -bromopropionate, phenyl trichloroacetate, a  : a  : b -trichloropropionitrile trichloroacetamide, trichloroacetyldiethylamide, N - trichloroacetylanilide, N : N1-di-(trichloroacetyl)methylene-diamine, N : N1 - di - (trichloroacetyl)ethylenediamine, interpolymers of asymmetrical dichloroethylene and vinyl chloride, and chloranil.  Plasticizers, anti-oxidants, pigments and fillers may be added to the mix. According to examples: (1) an interpolyamide from o -aminocaproic acid and hexamethylenediammonium sebacate is milled with paraformaldehyde and phthalic anhydride at 60-70 DEG  C., and the compounded material is heated in a mould, under pressure, at 141 DEG C. for 25 minutes; (2) the paraformaldehyde in (1) is replaced by dimethylolurea dimethylol ether; (3) a film is cast from a solution of an interpolyamide from hexamethylenediammonium adipate and caprolactam, dimethylolurea dimethyl ether and phthalic anhydride in aqueous ethanol, and the film is then heated at 110 DEG  C. for 25 minutes; (4) an interpolyamide from hexamethylenediammonium adipate, hexamethylenediammonium sebacate and caprolactam is plasticized with butylphthalyl butyl glycollate and diphenylol octadecane, and then milled with dimethylolurea dimethyl ether and phthalic anhydride at 50-60 DEG  C. The compounded material is heated in a mould, under pressure, at 141 DEG  C. for 15 minutes; (5) the interpolyamide of (4) is dissolved, with dimethylolurea dimethyl ether, in aqueous ethanol, and a film, cast from the solution, is heated at 150 DEG  C. for 25 minutes; (6) an interpolyamide from 12-amino-stearic acid and o -aminocaproic acid is milled with phthalic anhydride and paraformaldehyde at 70-80 DEG  C., and the compounded material is heated in a mould, under pressure, at 141 DEG  C. for 30 minutes; (7) a polyamide from 12-amino-stearic acid is milled with paraformaldehyde and phthalic acid, and the compounded material is heated in a mould, under pressure, at 141 DEG  C. for 30 minutes; (8) an interpolyamide from hexamethylenediammonium sebacate and 12-amino stearic acid is treated as in (7); (9) a polyester-amide from hexamethylene diammonium adipate, ethylene glycol and adipic acid is compounded with carbon black, paraformaldehyde and phthalic anhydride at 60-80 DEG  C., and the compounded material is heated in a mould, under pressure, at 141 DEG  C.; (10) an interpolyamide from hexamethylenediammonium sebacate and N : N1-dimethyl-hexamethylene diammonium sebacate is milled, at 70-90 DEG  C., with paraformaldehyde and 1-bromo-2-naphthol.  The compounded material is heated in a mould, under pressure, at 125 DEG  C. for 45 minutes. Specifications 461,237, 534,698, 540,135, 540,576, 557,544 and 580,524 are referred to.