Patent GB-936760-A (GB)
Title: Process for stabilising polymers of ethylenically unsaturated hydrocarbons; novel substituted monophenols suitable for use therein and process for preparing these
IPC: C07C37/14
Filed: 1961-06-08
Abstract: Polymers or copolymers of ethylenically unsaturated hydrocarbons, particularly polymers and copolymers of ethylene, propylene and the butylenes obtained by means of metal compounds, are stabilized by the addition thereto of a monophenol in which at least two ring carbon atoms are bound to separate hydrocarbon radicals at least one of the radicals being a norbornyl group (i.e. a bicyclo-(2,2,1)-heptyl group which one or more hydrogen atoms may be substituted by an alkyl radical but not more than one hydrogen atom per norbornyl carbon atom excluding that forming the monatomic bridge, the latter carbon atom always being bound to two hydrogen atoms.  It is preferred to use the monophenols in combination with one or more organic sulphides of the R1-Sx-R2 type, wherein x is an integer and R1 and R2 represent similar or dissimilar radicals containing carbon atoms bound to Sx. Polymeric products of the type of the polyalkoxy alkyl sulphides (-R1-O-R1-S-)x, polyalkoxy alkoxy alkyl sulphides (-R1-O-R2-O-R1-S-)x or polyhydroxy alkyl sulphides (-R1(OH)-S-)x as further described in Specification 834,291 may also be used in combination with the monophenols.  Specified sulphide compounds are the beta-thio-ethers of propionic acid esters, e.g. dilauryl-beta-thio dipropionate, and thiuram disulphide, n-dodecyl-cetyl monosulphide, didodecyl disulphide, dicetyl monosulphide, dicetyl disulphide, di-eicosyl monosulphide and dieicosyl disulphide.  Generally each of the stabilizers is used in an amount between 0.001 and 1% by weight based on the polymer. Specification 836,807 is referred to.ALSO:Substituted monophenols in which at least two ring carbon atoms are bound to separate hydrocarbon radicals, at least one of the radicals being a norbornyl group (i.e. bicyclo (2,2,1)-heptyl group) of which one or more hydrogen atoms may be substituted by an alkyl radical but not more than one hydrogen atom per norbornyl carbon atom excluding that forming the monatomic bridge, the latter carbon atom being bound to two hydrogen atoms, are prepared by reacting a monophenol with norbornene or an alkyl norbornene in the presence of an acid alkylation catalyst, e.g. a BF3-etherate, at preferably below 100 DEG C.  Phenols in which at least one of the hydrocarbon radicals is a norbornyl group of which no hydrogen atoms are substituted are claimed per se. Preferred monophenols are those in which the para position and at least one of the ortho positions with respect to the hydroxyl group are occupied by a hydrocarbon radical; the presence of norbornyl groups or alkyl substituted norbornyl groups in the para position and/or in an ortho position and/or in both ortho positions is particularly preferred.  In so far as the hydrocarbon radicals are not norbornyl groups preference is given to acyclic hydrocarbon radicals, especially branched alkyl groups, e.g. isopropyl tert. butyl, 2-hexyl, 3-nonyl and sec. hexadecyl. Examples are given of the preparation of 2,4,6-trinorbornyl phenol, 2-methyl-4,6-dinorbornyl phenol, 4-methyl-2,6-dinorbornyl phenol, 4-norbornyl-2,6-ditert. butyl phenol, 4-tert. butyl-2,6-dinorbornyl phenol, 2,4-dimethyl-6-norbornyl phenol, 2,6-dimethyl-4-norbornyl phenol, 2,4-disec. hexadecyl-6-norbornyl phenol, 2,4,6-tri(n-butylnorbornyl) phenol, 2-methyl-4,6-di(n-butylnorbornyl) phenol and 4-methyl- 2,6- di(n-butylnorbornyl) phenol. Other monophenols mentioned are 2-methyl-3,5,6-trinorbornyl phenol, 2,4-dimethyl-3,6-dinorbornyl phenol and 2,6-dimethyl-3,4-dinorbornyl phenol.  The monophenols may be used as stabilizers for polymers or copolymers of ethylenically unsaturated hydrocarbons (see Group IV(a)).  Specifications 834,291 and 836,807 are referred to.