Patent GB-902022-A (GB)
Title: The whitening of polymeric materials
Inventor: KEATS GEORGE HAROLD
IPC: D06L4/65
Filed: 1959-08-07
Abstract: A detergent composition comprises a soap, fatty alcohol-ethylene oxide condensate, alkylaryl sulphonate, or sulphonated alkyl naphthalene such as methylene bis(naphthalene-sulphonate) and a fluorescent brightening agent which is a pyridine compound, free from chromophoric and auxochromic groups, carrying a styryl substituent in the 2- or 4-position and containing at least one other aromatic or heterocyclic ring, which may be another styryl substituted, the said aromatic or hetero cyclic ring and the first mentioned styryl substituent being conjugated with the pyridine ring.  The pyridine compound may be substituted by alkyl, alkoxy, sulphonic acid, sulphonamide or carboxyl groups or by chlorine atoms.  Specified pyridine compounds are 1:4 bis (b -pyrid-21-yl vinyl-benzene), 4-(b -pyrid21-yl-vinyl-diphenyl), 1:4 bis(b -pyrid-41-yl-vinylbenzene), 2:6-distyrylpyridine, 2:6-di(41-methoxystyryl) pyridine and 2:6-di(41-chlorostyryl) pyridine.  The composition may also contain other whitening agents, e.g. 4:41-ditriazinyl aminostilbene-2:21-disulphonic acids, and sodium tripolyphosphate.ALSO:Synthetic polymeric materials, e.g. polyamides, polyesters polyurethanes, polyacrylonitrile, hydrolysed polyacrylonitriles, polymethyl methacrylate, polystyrene, polyethylene and polypropylene, are whitened by mixing them in the molten or plasticized form with a pyridine compound, free from chromophoric or auxochromic groups, carrying a styryl substituent in the 2- or 4-position and containing at least one other aromatic or heterocyclic ring, which may be another styryl substituent, the said aromatic or heterocyclic ring and the firstmentioned styryl substituent being conjugated with the pyridine ring.  The pyridine compounds may be substituted by alkyl, alkoxy, sulphonic acid, sulphonamide or carboxyl groups or by chlorine atoms.  Specified pyridine compounds are 1:4-bis(b -pyrid-21-yl-vinyl-benzene), 4-(b -pyrid-21-yl-vinyl-diphenyl), 1:4-bis(b -pyrid-41-yl-vinyl-benzene), 2:6-distyryl pyridine, 2:6-di(41-methoxy-styryl)pyridine and 2:6-di(41-chlorostyryl)pyridine.  The pyridine compound may be used in conjunction with other whitening agents, e.g. 4:41-ditriazinyl aminostilbene-2:21-disulphonic acids.ALSO:1:4-bis(b  - pyrid - 21 - ylvinyl)benzene, 4-(b -pyrid - 21 - yivinyl)diphenyl, 1:4-bis(b -pyrid-41-ylvinyl)benzene, 2:6-distyryl pyridine, 2:6-di (41-methoxystyryl)pyridine and 2:6-di(41-chlorostyryl)pyridine are prepared by reacting the appropriate aromatic aldehyde, e.g. terephthaldehyde, diphenyl-4-aldehyde, p-anisaldehyde or p-chlorbenzaldehyde, with the appropriate 2- or 4-methyl- or 2,6-dimethyl-pyridine in the presence of acetic anhydride, zinc chloride or piperidine.ALSO:Polymeric fibrous materials, e.g. polyamides, polyesters, polyurethanes, polyacrylonitrile, hydrolysed polyacrylonitriles, polymethyl methacrylate, polystyrene, polyethylene, polypropylene, secondary cellulose acetate, cellulose triacetate, regenerated cellulose, cotton, paper, silk and wool, are whitened by treating them with an aqueous medium containing a pyridine compound, free from chromophoric or auxochromic groups, carrying a styryl substituents in the 2- or 4-position and containing at least one other aromatic or heterocyclic ring, which may be another styryl substituent, the said aromatic or heterocyclic ring and the first mentioned styryl substituent being conjugated with the pyridine ring.  The pyridine compounds may be substituted by alkyl, alkoxy, sulphonic acid, sulphonamide or carboxyl groups or by chlorine atoms.  Specified pyridine compounds are 1 : 4-bis(b -pyrid-21-yl-vinylbenzene), 4-(b -pyrid- 21-ylvinyl-diphenyl), 1 : 4-bis(b -pyrid-41-yl-vinyl-benzene), 2 : 6- distyrylpyridine, 2 : 6-di(41-methoxystyryl)pyridine and 2 : 6-di(41-chlorostyryl)pyridine.  The polymeric fibrous material may be treated with an aqueous solution of the pyridine compound or with a neutral, acid or alkaline aqueous suspension thereof at 30 DEG -100 DEG C.  The treating composition may contain surface-active agents, e.g. fatty alcohol-ethylene oxide condensates or sulphonated alkyl-naphthalenes, or other whitening agents, e.g. 4 : 41-ditriazinylaminostilbene-2 : 21-disulphonic acids, or the pyridine compound may be dispersed in a soap or detergent.  The pyridine compounds may be applied to textile materials at the same time as dispersed dyestuffs or incorporated into discharge pastes containing, for example, sodium sulphoxylate formaldehyde to obtain superior white discharge effects by overprinting a dyed fabric.  The pyridine compound may be stripped from textile materials with aqueous sodium hydrosulphite in the presence of an alkali.