Compositions: coating or plastic – Materials or ingredients – Pigment – filler – or aggregate compositions – e.g. – stone,...
Patent
1998-02-17
2000-10-03
Green, Anthony
Compositions: coating or plastic
Materials or ingredients
Pigment, filler, or aggregate compositions, e.g., stone,...
106498, 546186, 546190, 546191, C08K 53435, C08J 322
Patent
active
061267368
DESCRIPTION:
BRIEF SUMMARY
The invention relates to the use of certain piperidine compounds of formula I below for stabilizing natural or synthetic, organic or inorganic pigments or pigment mixtures in natural or synthetic, polymeric or prepolymeric substrates against the adverse effects of heat and/or light on the light fastness and colour stability, respectively, especially against alterations in shade or light-induced bleaching. The invention also relates to a masterbatch composition comprising at least one piperidine compound of formula I below, at least one organic or inorganic pigment and a natural or synthetic material which is identical or compatible with the natural or synthetic, polymeric or prepolymeric substrate to be pigmented. The invention additionally relates to a method of stabilizing organic or inorganic pigments or pigment mixtures in natural or synthetic, polymeric or prepolymeric substrates against the adverse effects of heat and/or light on the light fastness and colour stability, respectively, especially against alterations in shade or light-induced bleaching, by adding an amount, effective for stabilization, of at least one piperidine compound of formula I below, as such or in the form of a masterbatch composition, to the pigment or pigment mixture to be stabilized or to the natural or synthetic, polymeric or prepolymeric substrate comprising the pigment or pigment mixture.
Pigments are colorants which are insoluble or of extremely low solubility. Colorants generally comprise groups of atoms known as chromophoric groups, which induce colour in molecules, and auxochromic groups, which although not themselves colour-inducing reinforce the colour intensity and depth of colour. These groups of atoms can be damaged by energy supplied in the form of heat or light. Therefore, one speaks of the colour fastness of pigments. For example, in a coloured finished article which in the course of its use is exposed to the effect of heat and/or of natural or artificial light, especially its UV component, the established shade is altered or its intensity, i.e. depth of colour, decreases.
The object of the invention, therefore, is to improve the light fastness and colour intensity of pigments and the service life of the pigmented end products.
This object is achieved by the technical teaching of Patent claims 1 and 9 and, respectively, 11.
It has surprisingly been found that the presence of certain piperidine compounds of formula I below substantially improves the colour fastness of pigments or pigment mixtures.
It is known that compounds of the HALS type (HALS=hindered amine light stabilizer) react as free-radical scavengers and are therefore used to stabilize polymeric substrates. These commercially available HALS compounds, however, do not have a specific light-stabilizing action on pigments.
The invention accordingly provides for the use of piperidine compounds of the formula I ##STR2## in which R.sub.1 is hydrogen, hydroxyl, lower alkyl, lower alkoxy or acyl, is aromatic in type, mixtures thereof in natural or synthetic, polymeric or prepolymeric substrates against the adverse effects of heat and/or light on the light fastness and colour stability, respectively, especially against alterations in shade or light-induced bleaching.
By lower alkyl are meant preferably radicals having 1 to 8, especially 1 or 2, carbon atoms; suitable acyl radicals are preferably the radicals of formic, acetic or propionic acid.
All radicals R.sub.1 are preferably hydrogen, hydroxyl, methyl or C.sub.1-8 -alkoxy, especially methyl.
Among mono- or bicyclic radicals R.sub.2 which are aromatic in type suitable examples are benzene, naphthalene and nitrogen- and/or sulphur-containing five- or six-membered rings with or without a fused-on benzene ring, which carry sterically hindered hydroxyl, for example, as a substituent (3,5-di-tert-butyl-4-hydroxyphenyl), or a thienyl radical. Six-membered aromatic rings are preferred. Examples of substituents which may be present on these rings are hydroxyl, lower alkyl or alkoxy, preferably methyl, tert-butyl, m
Ligner Gilbert
Stoll Klaus
Thuermer Andreas
Webster Joseph Reni
Clariant Finance (BVI) Limited
Green Anthony
Jackson Susan S.
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