Patent GB-617907-A (GB)
Title: Manufacture of aqueous dispersions of synthetic linear polyamides
IPC: C08J3/05
Filed: 1946-04-17
Abstract: Aqueous dispersions of polyamides are prepared by gradually milling water into a synthetic linear polyamide at a temperature below 100 DEG  C. in the presence of a dispersing agent until a polyamide-in-water dispersion is formed, the polyamide being one which is rendered plastic at a temperature below 100 DEG  C. in the presence of water and is capable of being so milled.  The polyamide may be an N-substituted polyamide bearing on the recurring nitrogen the group -CH2-O-R, R being the non-hydroxyl portion of an alcohol and preferably an alkyl or a hydrocarbon radical, e.g. N-methoxymethyl-, N-isobutoxymethyl-, N-allyloxymethyl-, polyhexamethylene adipamide and the N-bezyloxy-methyl polyamide derived from a mixture of hexamethylene diammonium adipate and hexamethylene diammonium sebacate, but is preferably an interpolyamide obtainable from 6-aminocaproic acid or caprolactam and two of the three following ingredients, viz.: hexamethylene-diammonium adipate, hexamethylene-diammonium sebacate and a mixture of hexamethylene - diammonium suberate and hexamethylene-diammonium azelate. According to examples: (1) N-methoxymethyl polyhexamethylene adipamide having 45 per cent of its amide groups substituted by methoxymethyl groups is milled in a mixer at 110 DEG  C., partially hydrolysed polyvinyl acetate and sodium lauryl sulphate are added, the steam used to heat the mixer is turned-off and water is gradually added; (2) a polyamide interpolymer prepared from hexamethylenediammonium adipate and hexamethylenediammonium sebacate and caprolactum is milled in a mixer at 120 DEG  C., partially hydrolysed polyvinyl acetate is added, the heat is turned off and water is gradually added; (3) a polyamide interpolymer of the kind used in example (2) is milled in a mixer at 120 DEG  C., a plasticizer composed of a mixture of N-ethyl o- and p-toluenesulphonamides is added, followed by partially hydrolysed polyvinyl acetate and sodium lauryl sulphate, after complete incorporation, steam heat is turned-off and water is gradually added. An alternative procedure is to mill the polyamide with a little water at or below 100 DEG  C., adding the dispersing agent and continuing milling and adding water; or to mill the polymer at or below 100 DEG C. with a concentrated aqueous solution of the emulsifying agent then gradually adding more water.  Other specified emulsifying agents are polyvinyl alcohol, methyl cellulose, natural gums, soaps, sodium salts of long chain alkyl sulphates or sulphonates, ammonium oleate, stearyl trimethylammonium bromide, cetyl pyridinium bromide, sorbitan monooleate modified with ethylene oxide.  The emulsifying agent may be formed in situ.  Other specified plasticizers are diphenyloloctadecane and methyl-10-phenylol stearate.  Pigments, fillers and resins may also be added.  Specifications 557,544 and 573,482, [both in Group IV], are referred to.ALSO:Aqueous dispersions of polyamides are prepared by gradually milling water into a synthetic linear polyamide at a temperature below 100 DEG  C. in the presence of a dispersing agent until a polyamide-in-water dispersion is formed, the polyamide being one which is rendered plastic at a temperature below 100 DEG  C. in the presence of water and is capable of being so milled.  The polyamide may be an N-substituted polyamide bearing on the recurring nitrogen the group -CH2-O-R, R being the non-hydroxyl portion of an alcohol and preferably an alkyl or a hydrocarbon radical, e.g. N - methoxymethyl-, N - isobutoxymethyl-, N - allyloxymethyl - polyhexamethylene adipamide and the N-benzyloxy-methyl polyamide derived from a mixture of hexamethylene diammonium adipate and hexamethylene diammonium sebacate, but is preferably an inter-polyamide obtainable from 6-aminocaproic acid or caprolactam and two of the three following ingredients, viz. hexamethylene - diammonium adipate, hexamethylene-diammonium sebacate and a mixture hexamethylene-diammonium suberate and hexamethylene - diammonium azelate.  According to examples: (1) N-methoxymethyl polyhexamethylene adipamide having 45 per cent of its amide groups substituted by methyoxymethyl groups is milled in a mixer at 110 DEG C., partially hydrolysed polyvinyl acetate and sodium lauryl sulphate are added, the steam used to heat the mixer is turned off and water is gradually added; (2) a polyamide interpolymer prepared from hexamethylene-diammonium adipate and hexamethylenediammonium sebacate and caprolactam is milled in a mixer at 120 DEG  C., partially hydrolysed polyvinyl acetate is added, the heat is turned off and water is gradually added; (3) a polyamide interpolymer of the kind used in example (2) is milled in a mixer at 120 DEG  C., a plasticizer composed of a mixture of N-ethyl o- and p-toluenesulphonamides is added followed by partially hydrolysed polyvinyl acetate and sodium lauryl sulphate, after complete incorporation, steam heat is turned off and water is gradually added. An alternative procedure is to mill the polyamide with a little water at or below 100 DEG  C., adding the dispersing agent and continuing milling and adding water; or to mill the polymer at or below 100 DEG C. with a concentrated aqueous solution of the emulsifying agent then gradually adding more water.  Other specified emulsifying agents are polyvinyl alcohol, methyl cellulose, natural gums, soaps, sodium salts of long chain alkyl sulphates or sulphonates, ammonium oleate, stearyl trimethylammonium bromide, cetyl pyridinium bromide, sorbitan monooleate modified with ethylene oxide.  The emulsifying agent may be formed in situ.  Other specified plasticisers are diphenyloloctadecane and methyl-10-phenylol stearate.  Pigments, fillers and resins may also be added.  N-methoxymethyl polyhexamethylene adipamide is prepared by heating a mixture of polyhexamethylene adipamide, paraformaldehyde and methanol to 140 DEG C., adding phosphoric acid and after a short interval discharging the mixture into methanol containing enough ammonia to neutralize the phosphoric acid.  The polymer is then precipitated by the addition of water, washed with water and dried.  A polyamide interpolymer is prepared by heating hexamethylene-diammonium adipate, hexamethylene - diammonium sebacate and capro-lactam in an autoclave at 200-220 DEG C. for three hours at 250 lbs. per sq. in., reducing the pressure to atmospheric while increasing the temperature to 240-250 DEG  C. during the course of 2 hours and then holding under a reduced pressure of 30-50 mm. for 2 hours at the same temperature. Specifications 557,544 and 573,482 are referred to.