PROCEDIMIENTO PARA LA PROTECCIËN DE MATERIALES SENSIBLES A LA LUZ

摘要

1-hydroxyxanthone compounds of the general formula wherein S1 and S3 individually each represent hydrogen, an alkyl group of 1 to 12 carbon atoms or a halogen atom, S2 and S4 are individually the same as S1 and S3 or each is a hydroxyl or an alkoxy group of 1 to 12 carbon atoms or a said alkoxy group containing an hydroxy substituent and n and m each represent 1 or 2 are incorporated in or coated on various polymeric carriers to produce ultra-violet light absorbing materials. Plasticisers, antioxidants, heat stabilizers and pigments may also be incorporated. In the examples suitable carriers include polyester resins obtained for example from a mixture of polyethylene glycol with methyl methacrylate or from 1, 4, 5, 6, 7, 7-hexachlorobicyclo-(2,2,1)-5,heptene-2,3-dicarboxylic acid; a nitro lacquer containing soluble gun cotton, an alkyd resin mixture, dioctyl phthalate, ethyl acetate, methyl ethyl ketone and toluene; and films or plates produced from cellulose 2 1/2 -acetate or cellulose acetobutyrate, polystyrene, polymethyl methacrylate, polyvinyl butyral, nylon 6, polyethyleneglycol terephthalate, polyethylene, poly-propylene, and a mixture of polyvinyl chloride with dioctyl phthalate. Polymeric polyolefins may be stabilized by hydroxyxanthones of the above general formula wherein S1 and/or S3 are alkyl groups containing 6-12 carbon atoms and/or S2 and/or S4 are similar alkyl groups or alkoxy groups containing 6-12 carbon atoms.ALSO:1-Hydroxyxanthone compounds of the general formula: wherein S1 and S3 individually each represent hydrogen, an alkyl group of 1 to 12 carbon atoms or a halogen atom, S2 and S4 are individually the same as S1 and S3 or each is a hydroxyl or an alkoxy group of 1 to 12 carbon atoms or a said alkoxy group containing an hydroxy substituent and n and m each represent 1 or 2 may be prepared by distilling 2-hydroxy benzene-1-carboxylic acid compounds of the general formula:- wherein S3 and S4 and n have the meanings given above, with 1,3-dihydroxy benzene compounds of the general formula:- wherein S1, S2 and m have the meanings given above, the distillation being performed at normal pressure, possibly in the presence of condensing agents such as acetanhydride. Such 1-hydroxyxanthone compounds may also be formed by heating the above starting materials in the presence of water-binding condensing agents such as phosphorus oxychloride or anhydrous zinc chloride, advantageously to 50-100 DEG C. 1-Hydroxyxanthone compounds containing alkoxy groups are obtained, for example, from polyhydroxanthane compounds by alkaline condensation with aliphatic halides, sulphuric acid esters or half esters. Preparations for 1-hydroxy-2,4-di-tert butyl-xanthone, 1 - hydroxy - 3 - (b -hydroxyethoxy)-xanthone and 1-hydroxy-3,6-bis-(b -hydroxyethoxy)-xanthone are particularly described in Example 1.