Patent GB-371901-A (GB)
Title: Improvements in coatings or coverings for protection against light
IPC: C09D101/12
Filed: 1930-10-24
Abstract: The effective life of cellulose nitrate lacquers such as those used for motor-car bodies, which lose their lustre on weathering and particularly after long exposure to ultra-violet rays from the sun, is lengthened by applying to the surface an overcoating of a varnish or lacquer comprising a cellulose ester containing from 0,25 to 5 per cent of an organic substance (except diphenyl benzene) which is colourless or if coloured is not a dyestuff and absorbs those wavelengths of the ultra-violet that penetrate the atmosphere. Substances specified are polycyclic hydrocarbons or their derivatives such as phenanthrene, naphthalene, chloronaphthalene, or anthracene, or certain other aromatic hydrocarbons which are not polycyclic namely p-aminobenzoic acid, phthalimide, nitro-anisol, nitro-benzene, quinaldine, benzyl benzoate, glycerol, butyl phthalate, and b -methoxyethyl phthalate.  The cellulose esters specified as overcoating material are the acetate or other aliphatic acid ester, or a mixed inorganic-aliphatic acid ester may be used.  Certain plasticizers such as triphenyl-phosphate may be added.  In an example, cellulose acetate is mixed with 0,25 to 5 per cent of the light filter with or without the addition of say 50 per cent of a plasticizer, and the mixture dissolved in the proportion of 20 ounces to 1 gallon of a solvent mixture containing ethyl acetate 15 per cent, acetone 50 per cent, ethyl lactate 20 per cent, and denatured alcohol 15 per cent.  The cellulose acetate overcoating may consist of an already formed sheet containing the light filter which is superposed upon the cellulose nitrate sheet to be protected.  In the case of laminated glass, the cellulose derivative reinforcement interposed between the glass laminations may consist of a cellulose nitrate interlayer coated on either side with cellulose acetate containing the light filter. Specification 370,699 is referred to. According to the Provisional Specification the cellulose ester may be cellulose aceto-propionate, cellulose aceto-benzoate, cellulose nitro-acetate, cellulose phospho-acetate, cellulose propionate or cellulose butyrate; and as light filter o, m, or p diphenyl benzene or diphenylguanidine.ALSO:The effective life of cellulose nitrate lacquers such as those used for motor car bodies, which lose their lustre on weathering and particularly after long exposure to ultra-violet rays from the sun, is lengthened by applying to the surface an overcoating of a varnish or lacquer comprising a cellulose ester containing from 0.25-5 per cent of an organic substance (except diphenyl benzene) which is colourless or if coloured is not a dyestuff and absorbs those wave lengths of the ultra-violet that penetrate the atmosphere.  Substances specified are polycyclic hydrocarbons or their derivatives such as phenanthrene, naphthalene, chloronaphthalene, or anthracene, or certain other aromatic hydrocarbons which are not polycyclic, namely p-aminobenzoic acid, phthalimide, nitro-anisol, nitro-benzene, quinaldine, benzyl benzoate, glycerol butyl phthalate, and b -methoxyethyl phthalate. The cellulose esters specified as overcoating material are the acetate or other aliphatic acid ester, or a mixed inorganic aliphatic acid ester may be used.  Certain plasticizers such as triphenyl-phosphate may be added.  In an example, cellulose acetate is mixed with 0.25-5 per cent of the light filter with or without the addition of say 50 per cent of a plasticizer, and the mixture dissolved in the proportion of 20 ounces to 1 gallon of a solvent mixture containing ethyl acetate 15 per cent, acetone 50 per cent, ethyl lactate 20 per cent, and denatured alcohol 15 per cent.  The cellulose acetate overcoating may consist of an already formed sheet containing the light filter which is superposed upon the cellulose nitrate sheet to be protected.  In the case of laminated glass, the cellulose derivative reinforcement interposed between the glass laminations may consist of a cellulose nitrate interlayer coated on either side with cellulose acetate containing the light filter. Specification 370,699 is referred to. According to the Provisional Specification the cellulose ester may be cellulose acetopropionate, cellulose aceto-benzoate, cellulose nitro-acetate, cellulose phospho - acetate, cellulose propionate, or cellulose butyrate; and as light filter o-, m- or pdiphenyl benzene or diphenylguanidine.