Patent GB-952971-A (GB)
Title: Polymeric compositions stabilised against actinic degradation
IPC: C09K15/08
Filed: 1962-02-12
Abstract: Esters of 3, 5-dialkyl -4- hydroxybenzoic acids, in which at least one of the alkyl groups is branched on the a -carbon atom, may be prepared (1) by esterifying the acid with an alcohol, (2) reacting the acid with a hydrocarbon chloride or (3) reacting the chloride of the acid with an alcohol. The esters may be (1) esters with monohydric alcohols, preferably containing 1-20 carbon atoms; specified products of this class include chloromethyl 3, 5-di-tert.-butyl 3-4-hydroxybenzoate, 1, 2-dibromoethyl 3, 5-diisopropyl -4- hydroxybenzoate, 3-fluoropropyl 3, 5-di-tert.-amyl-4-hydroxybenzoate, cyclohexyl 3-isopropyl -5- tert.-butyl -4- hydroxybenzoate, lauryl 3-methyl -5- isoamyl -4- hydroxybenzoate and stearyl 3, 5-diisopropyl -4- hydroxybenzoate; (b) esters with acylic or cyclic unsaturated mono-or poly-hydric alcohols, e.g. allyl 3, 5-di-tert.-butyl -4- hydroxybenzoate, oleyl 3-methyl -5-tert.-amyl -4- hydroxybenzoate and 3-cyclohexenyl 3, 5-di-sec.-heptyl -4- hydroxybenzoate and their halogenated isomers; (c) esters with polyhydric alkanols having, preferably, 2-10 carbon atoms and up to six hydroxyl groups, e.g. propane -1-3-di-(3, 5-di-tert.-butyl -4- hydroxy benzoate), pentane -1,3, 5-tri(3,5-di-tert.-amyl -4 hydroxybenzoate) and pentaerythrityl tetra (3, 5-diisopropyl -4- hydroxybenzoate); (d) esters of aromatic hydroxy compounds e.g. phenol, durenols, hydroquinone, phloroglucinol, a - and b -naphthol or 9, 10-dihydroxyanthracene, specified compounds including p-octylphenyl 3, 5-di-tert.-butyl -4- hydroxybenzoate, naphthyl 3, 5-diisopropyl -4- hydroxybenzoate, benzene 1, 3, 5-tri(3, 5-di-tert.-butyl -4- hydroxybenzoate) anthracene 9, 10-di(3, 5-di-tert.-hexyl -4- hydroxybenzoate), p-chlorophenyl 3, 5-di-tert.-butyl -4-hydroxybenzoate and 2, 4-dibromophenyl 3, 5-diisopropyl -4- hydroxybenzoate. In the examples, (1) p-octylphenol 3, 5-di-tert.-butyl -4- hydroxybenzoate is prepared by heating p-octylphenol with 3, 5-di-tert.-butyl -4- hydroxybenzoic acid; naphthalene-2, 7-di(3, 5-di-tert.-butyl -4- hydroxy benzoate) is similarly obtainable; (2) 21, 41-ditert.-butylphenyl 3, 5-di-tert.-butyl -4- hydroxybenzoate is obtained from 3, 5-di-tert.-butyl -4- hydroxybenzoyl chloride and 2, 4-di-tert.-butylphenol; (3) the dodecyl and allyl esters of 3, 5-di-tert.-butyl -4- hydroxybenzoic acid are prepared from the acid and the alcohol, as in Example 1; (4) trimethylene glycol and 3, 5-ditert.-butyl -4- hydroxybenzoyl chloride yield propane-1, 3-di(3, 5-di-tert.-butyl -4- hydroxybenzoate); (5) 1, 1, 1-trichloro -2-methyl -21-propanol and 3, 5-di-tert.-butyl -4- hydroxy benzoyl chloride yield 11, 11-dimethyl-21, 21, 21-trichlorethyl 3, 5-di-tert.-butyl -4- hydroxybenzoate; (6) trimethylolethane and 3, 5-di-tert. butyl -4- hydroxy benzoyl chloride yield 1, 1, 1-tri (3, 5-di-tert.-butyl -4- hydroxybenzoyloxymethyl) ethane.ALSO:As agents for protecting polymeric compositions from actinic degradation, use is made of 3,5-dialkyl-4-hydroxybenzoic acids in which at least one of the alkyl groups is branched on the a -carbon atom; the anhydrides, acid halides and esters of such acids may also be used. The esters of the acids with halogenated alcohols, e.g. chloromethyl 3,5-di-tert.-butyl-4-hydroxybenzoate, 1,2-dibromoethyl 3,5-diisopropyl-4-hydroxybenzoate or 3-fluoropropyl 3, 5-di-tert.-amyl -4- hydroxybenzoate, or the chloro-aromatic esters, e.g. p-chlorophenyl 3, 5-di-tert.-butyl -4- hydroxybenzoate or 2, 4-dibromophenyl 3, 5-diisopropyl -4- hydroxybenzoate, also have fire-retardant properties.  Many polymeric materials which may be stabilised are specified, including polyvinyl halides, polyvinyl esters, polystyrene, polymethacrylates, dihydric alcohol-dicarboxylic acid polyesters and cellulose esters, but the invention is particularly applicable to the stabilization of polyolefines, a number of which are specified. The stabilizer may be incorporated into the solid polymer by milling or, when the polymer is prepared from a liquid monomer, e.g. styrene, methyl methacrylate or propylene, the stabiliser may be dispersed in the monomer before polymerization or after forming the polymer but before removing the solvent.  The proportion of stabiliser may be 0.001-10%, preferably 0.1-1%.  The compositions may contain other additives also, e.g. plasticizers, pigments, fillers, dyes, glass or other fibres and thermal antioxidants, and in this connection a number of phenolic compounds suitable for use as antioxidants are specified, including biphenols, bis -(3, 5-dialkyl -4- hydroxybenzyl)-durenes, polyphenolic benzenes, e.g. 1, 3, 5-trimethyl-2, 4, 6-tris (3, 5-di-tert.-butyl -4- hydroxybenzyl)-benzene and di(3, 5-dialkyl -4- hydroxybenzyl) polynuclear aromatics, e.g. 9, 10-bis (3, 5-di-tert.-butyl -4- hydroxybenzyl)-anthracene. Examples of the treatment of polypropylene and polystyrene are given.  Esters of the acids specified above may be (1) esters with monohydric alcohols, preferably containing 1-20 carbon atoms; specified products of this class include the chloro, bromo and fluoro esters mentioned above, cyclohexyl 3-isopropyl -5-tert.-butyl -4- hydroxybenzoate, lauryl 3-methyl -5- isoamyl -4- hydroxybenzoate and stearyl 3, 5-diisopropyl -4- hydroxybenzoate; (b) esters with acyclic or cyclic unsaturated mono- or polyhydric alcohols, e.g. allyl 3, 5-di-tert.-butyl-4-hydroxybenzoate, oleyl 3-methyl-5-tert.-amyl-4-hydroxybenzoate and 3-cyclohexenyl 3, 5-di-sec.-heptyl -4-hydroxybenzoate and their halogenated isomers; (c) esters with polyhydric alkanols having, preferably, 2-10 carbon atoms and up to six hydroxyl groups, e.g. propane-1, 3-di (3, 5-tert.-di-butyl-4-hydroxy benzoate), pentane-1, 3, 5-tri(3, 5-di-tert.-amyl -4-hydroxybenzoate) or pentaerythrityl tetra(3, 5-diisopropyl -4-hydroxy-benzoate); (d) esters of aromatic hydroxy compounds, e.g. phenol, durenols, hydroquinone, phloroglucinol, a -and b -naphthol or 9, 10-dihydroxy-anthracene, specified compounds including p-octylphenyl 3,5-di-tert.-butyl-4-hydroxybenzoate, naphthyl 3,5-diisopropyl-4-hydroxybenzoate, benzene 1,3,5-tri-(3,5,di-tert.-butyl -4- hydroxybenzoate) and anthracene 9, 10-di (3, 5-di-tert.-hexyl -4- hydroxybenzoate), as well as the chloro- and bromo-aromatic esters mentioned above.  A number of acid halides suitable for use in the invention are also specified.