US3764585A
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Method for the production of synthetic polyamides, which comprises adding an aromatic aldehyde containing sulfonic acid groups to the reacting monomers
Abstract A method for obtaining synthetic polyamide yarns, more particularly polyamide yarns, is disclosed, which have a high affinity towards basic dyestuffs. The dyeability with basic dyestuffs is improved by adding to the polymerization mass, prior to, or during progress of, polymerization, an aromatic aldehyde having the general formula WHEREIN M AND N ARE INTEGERS WHICH ARE 1 OR 2, THE GROUP SO3X indicates both a free sulphonic group or such a group salified with a member selected from the group consisting of ammonium ions, alkali metals and alkaline earth metals. Hypophosphorous acid, or an alkali metal salt thereof can also be added to improve the whiteness of the parts of the yarn or fabric which are not to be dyed.
A method according to claim 1, wherein the additive is added to the polyamide monomer at the beginning of the polymerization.
Claim 2
Dependent Claim
23 words
A method according to claim 1, wherein there are used from 10 to 100 mols of aldehyde per 106 grams of polymer obtained.
Claim 3
Dependent Claim
35 words
A method according to claim 1, wherein also hypophosphorous acid or an hypophosphite of an alkali metal is added in an amount ranging from 0.25 mol to 1 mol, per each mol of aldehyde added.
Claim 4
Dependent Claim
19 words
A method according to claim 1, wherein the added aldehyde is 4-formylbenzene-1:3-bisulphonic acid or the alkali metal salts thereof.
Claim 5
Dependent Claim
19 words
A method according to claim 1, wherein the added aldehyde is 2-formyl-benzene-1-sulphonic acid or the alkali metal salts thereof.
Claim 6
Dependent Claim
11 words
A method according to claim 4, wherein lithium hypophosphite is used.
Claim 7
Dependent Claim
19 words
A method according to claim 1 wherein the produced polyamide is polycapronamide (nylon-6) or hexamethylene diamine polyadipate (nylon 66).