Patent GB-622300-A (GB)
Title: Improvements in or relating to plastic composition
IPC: C08K13/02
Filed: 1946-12-19
Abstract: A cellulose ether composition is rendered resistant to discolouration by heat during moulding or other shaping operations or during use by incorporating in the composition sulphur dioxide or a compound which has the property of releasing sulphur dioxide upon heating to 200 DEG C. or below, and a cyclic saturated terpene, one hydrogen of which is substituted by a phenolic group which may contain alkyl, alkoxyl, or other substituents provided that at least two of the nuclear hydrogen atoms remain unsubstituted.  The composition is shaped at a temperature sufficient to release sulphur dioxide from the compound containing it.  Instead of incorporating the sulphur compound in the production of the moulding composition, a moulding powder containing the cellulose ether and the terpene compound may be subjected to an atmosphere of sulphur dioxide, so that it absorbs some of the sulphur dioxide, and the composition is moulded under heat before the absorbed sulphur dioxide has been lost.  As a further alternative, the cellulose ether composition containing the terpene compound may be moulded while passing a small stream of sulphur dioxide into the moulding chamber or into a chamber or hopper by which the composition is led to the moulding chamber.  The cellulose ether may be an ethyl cellulose of ethoxyl content between 37 and 52 per p  cent.  Methyl, propyl, benzyl, and mixed cellulose ethers may also be used.  The cellulose ether should be free from acidity and if necessary it may be treated with metallic bases.  The compound which releases sulphur dioxide may be a sulphone, an aliphatic or cyclo-aliphatic sulphonate, an organic sulphite or bisulphite, or an inorganic bisulphite, metabisulphite, or hydrosulphite.  It may be a sulphone derived from butadiene, piperylene, isoprene, 2-methyl pentadiene, or amyldiene, or a polyalkylpolysulphone may be used.  It may be sodium sulpho-dipropyl succinate, diethyl sulphite, acetone bisulphite, sodium formaldehyde sulphoxylate, sodium bisulphite, or sodium hydrosulphite.  The proportion of combined or free sulphur dioxide is not more than 2 per cent, based on the weight of the cellulose ether, and preferably it is much less, e.g. 0.2 or even 0.005 per cent.  The terpene compound may be a substituted menthane, pinane, carane, camphane, fenchane, isobornylane, dicamphane, pinol, cineol, pinocamphone, santenol, santenone, fenchone, fenchyl alcohol, epicamphor, menthol, or carvomenthol.  The phenol group may be substituted by more than one saturated cyclic terpene group.  The terpene compound may be a reaction product of a phenol with a monocyclic terpene with one double bond or with a saturated terpene or with a dicyclic terpene with one double bond and which does not isomerize to form a terpene with more than one double bond. Monocyclic dihydro-terpenes specified are para-menthenes such as 1-, 2-, 3-, 1(7)-, 4(8)-, or 8-para-menthene.  Camphene, bornylene, a -, b -, and g -fenchenes are specified dicyclic terpenes.  Pinane and tricyclene are specified saturated terpenes which condense with phenol to form the desired stabilizing compounds.  The phenol employed in the condensation may be phenol itself or a cresol, butyl phenol, amyl phenol, xylenol, thymol, or guaiacol.  The monophenylol saturated terpenes are used in amounts of 0.5 to 5.0 per cent of the weight of cellulose ether.  Plasticizers, oils, resins, waxes, pigments, dyes, and fillers may be included in the composition. Shaping may be effected by compression moulding under heat, injection moulding, extrusion, or drawing.  The compositions may be used for making lacquer films, electrical insulation, coatings on fabrics, films, and sheets, as well as moulded articles.  In an example, 1-p-phenylol-p-menthane, prepared by hydrogenating one of the double bonds of dipentene and then condensing the product with phenol, is dissolved in dibutyl phthalate.  Butadiene sulphone is added and the solution is mixed in a roller-mill with ethyl cellulose.  The mass is stripped from the rolls as a sheet and then broken and ground to form a moulding powder.  A thin disc is moulded from the powder by compression at 200 DEG  C.  In another example, sodium sulphodioctyl succinate in dibutyl phthalate is mixed with ethyl cellulose and mono-phenylol isobornylane.ALSO:A cyclic saturated terpene, one hydrogen of which is substituted by a phenolic group, which may contain alkyl, alkoxyl, or other substituents, provided that at least two of the nuclear hydrogen atoms remain unsubstituted, is "incorporated" in cellulose ether compositions.  It may be a substituted menthane, pinane, carane, camphane, fenchane, isobornylane, dicamphane, pinol, cineol, pinocamphone, santenol, santenone, fenchone, fenchyl alcohol, epicamphor, menthol, or carvomenthol.  The phenol group may be substituted by more than one saturated cyclic terpene group.  The terpene compound may be a reaction product of a phenol with a monocyclic terpene with one double bond or with a saturated terpene, or with a dicyclic terpene with one double bond and which does not isomerize to form a terpene with more than one double bond.  Monocyclic dihydro-terpenes specified are paramenthenes such as 1-, 2-, 3-, 1(7)-, 4(8)-, or 8-, para-menthene.  Camphene, bornylene, a -, b -, and g -fenchenes are specified dicyclic terpenes.  Pinane and tricyclene are specified saturated terpenes which condense with phenol to form the desired compounds.  The phenol employed in the condensation may be phenol itself or a cresol, butyl phenol, amyl phenol, xylenol, thymol, or guaiacol.  In an example: 1-p-phenylol-p-menthane, prepared by hydrogenating one of the double bonds of dipentene and then condensing the product with phenol, is incorporated in ethyl cellulose.  In another example, mono-phenylol isobornylane is used. For the preparation of a phenylol menthane, dihydro-a -terpineol is subjected to vapour-phase catalytic dehydration at 275 DEG  C. to produce menthane which is added gradually to a solution of boron fluoride in phenol and benzene.  The reaction with phenol is allowed to continue at 20-30 DEG  C.  The washed reaction mixture is heated under reduced pressure to remove residual solvent and phenol.  The crystallized product is distilled under vacuum to obtain a final product of hydroxyl content of 7.5 per cent.  Instead of boron fluoride, the catalyst used may be hydrofluoric acid, mixtures of mineral acids, activated siliceous materials, or activated carbon. Condensation of phenols with other cyclic terpenes having one double bond may be effected in a similar manner.  If desired, the phenol may be condensed with a dihydroterpene halide or dihydroterpene alcohol.