Studies on Dyeing of Polypropylene Fibres

Abstract

IV) DYEING OF POLYPROPYLENE FIBRES WITH MONOAZO DISPERSE DYESThe monoazo disperse dyes for polypropylene fibres were synthesised. The relation between chemical structure and dyeing property of these dyes, namely influence of substituent, particularly of alkyl group, was investigated from fastness of dyeings. Aniline derivatives containing such substituents as halogen, alkyl (Cl-CB), N-alkylamino, trifluoromethyl, nitro, and amide group etc. were diazotized and coupled with alkylphenol, N-alkyl aniline, (3-naphthol, (3-hydroxynaphthoic acid and active methylene compounds.In these compounds substituents having affinity for polypropylene fibres are harogen atom, alkyl, hydroxyl and N-alkylamino group. The aliphatic property is introduced into dyes in excess, so that the fastness property as drycleaning fastnese is generally decreased. Therefore, the necessary conditions for dyes of polypropylene fibres are as follows ;(i ) aromatic nucleus gives hydrophobic property to dyes.(ii) aliphatic property is given with introduction of alkyl group into dye structure.(iii) the balance between aromatic and aliphatic property is proper.(iv) planar structure of dyes is coincident with those of fibres. But dyeings being wrapped in paper or polyethylene film, dyes easily migrate into them. Dyeings being left for several months, its fastness,particularly crocking fastness, is apt to decrease. (V) DYEING OF POLYPROPYLENE FIBRES WITH BISAZO DISPERS DYESBisazo disperse dyes for polypropylene fibres were synthesized. The relation between chemical structure and dyeing property of these dyes was studied. Aromatic monoazo amino compounds such as aminoazotoluene, 4-(N, N-dimethylamino)-4'-aminoazobenzene, 4-phenylazo-l-naphthylamine and 4n-butyl phenylazo-l-naphthylmine were diazotized and coupled with alkylphenol, N-alkylaniline, 1lnaphthol and (3-hydroxynaphthoic acid.These bisazo dyes with more aromatic nucleus than monoazo dyes, have larger molecule and become useful dyes for polypropylene fibres, only balance between aromatic and aliphatic property being property controlled by introduction of alkyl group. Namely, even if the dyeings were wrapped in polyethylene film, dyes are not migrated into them. Fastness of dyeings in bisazo dyes is generally better than in monoazo dyes. (Roceived August 2, 1962)