Patent GB-606807-A (GB)
Title: Production of synthetic elastomers
IPC: C08F236/04
Filed: 1945-05-16
Abstract: Synthetic elastomers are prepared by copolymerising at least 70 parts by weight of a branched chain 1,3-hexadiene having a straight chain of 5 carbon atoms or a mixture of such hexadienes, with no more than 30 parts of 1,3-butadiene, a 1,3-pentadiene or a mixture of such compounds.  Specified hexadienes are the 2,3 or 4-methyl-1,3-pentadienes.  Suitable pentadienes are isoprene and piperylene.  Polymerisation may be effected in bulk, solution or dispersion.  As catalysts, there may be used diazoaminoaryl compounds, e.g. diazoaminobenzene and p-benzene azo tolu benzylamine (with temperatures of above 65 DEG  C.), peroxides, perborates, persulphates and other oxygen-yielding compounds. Emulsifying agents, protective colloids, granulating agents, regulators, pH buffers, lubricants and antioxidants may be present.  The polymer may be precipitated or coagulated, washed and purified, e.g. by boiling with caustic alkali.  A latex may be produced by concentration of an emulsion polymer or by replacing the medium or by dispersing the polymer.  The polymers may be blended with plasticisers, examples of which are wood rosin, gum rosin, ester gum, alkyd resins, phenol-aldehyde resins, shellac, dibutyl sebacate, dibutyl, dicapryl and dioctyl phthalates, coal tar, coumarone resins, tricresyl phosphate, chlorinated tricresyl phosphate, alkoxy alkyl phosphates, dibenzoyl ether, triacetin, stearic acid, lauric acid and aromatic petroleum fractions. Tackifiers such as the higher unsaturated cyclic ketones and hydrogenation products thereof, some unsaturated hydrocarbons and ketone-aldehyde resins may be present.  Specified antioxidants include p-hydroxy diphenyl hydroquinone, phenyl betanaphthylamine and other amino compounds.  Fillers, e.g. carbon black and pigments, e.g. clay, calcium silicate, iron oxide, chromium oxide, zinc oxide and titanium dioxide may be incorporated. Vulcanisable compositions may contain the usual vulcanising agents and accelerators.  Plastic modifiers, some of which may be produced in situ, may be incorporated and include natural resins, urea-aldehyde resins, polymers and copolymers of unsaturated compounds, protein plastics and cellulose derivatives and natural rubber and synthetic rubbers, e.g. polymers of 1,3-butadiene, isoprene, piperylene, 2,3-dimethyl-1,3-butadiene, chloroprene and isobutylene, copolymers of 1,3-dienes with styrene and acrylonitrile and of butadiene with isobutylene, high molecular weight polyesters, polyvinyl halides and olefin polysulphides.  The products may be made into sheets, rods, tubes and coatings and are useful in the production of balloon coverings, umbrellas, raincoats, tents, table covers, shower curtains, garment bags, electrical insulation, friction tape, shoe soles and heels, printers' rolls and blankets and many other articles in which rubber is normally used.  They may also be used as plasticisers and tackifiers.  Specification 595,721 is referred to.ALSO:Synthetic rubber compositions comprise a copolymer prepared by copolymerizing at least 70 parts by weight of a branched chain 1, 3-hexadiene having a straight chain of 5 carbon atoms or a mixture of such hexadienes, with up to 30 parts of 1, 3-butadiene, a 1, 3-pentadiene or a mixture of such compounds (see Group IV(a)).  A latex may be produced by concentration of an emulsion polymer or by dispersing the polymer.  The polymers may be blended with plasticizers, e.g. wood rosin, gum rosin, ester gum, alhyd resins, phenyl-aldehyde resins, shellac, dibutyl sebacate, dibutyl, dicapryl and dioctyl phthalate, coal tar, coumarone resins, tricresyl phosphate, chlorinated tricresyl phosphate, alkoxy alkyl phosphates, dibenzoyl ether, triacetin, stearic acid, lauric acid and aromatic petroleum fractions.  Other plastic modifiers, some of which may be produced in situ, may be incorporated and include natural resins, urea-aldehyde resins, polymers and copolymers of unsaturated compounds, protein plastics and cellulose derivatives, and natural or synthetic rubbers, e.g. polymers of 1, 3-butadiene, isoprene, piperylene, 2, 3-dimethylbutadiene, chloroprene and isobutylene, copolymers of 1, 3-dienes with styrene and acrylonitrile and of butadiene with isobutylene, high molecular weight polyesters, polyvinyl halides and olefin polysulphides.  Tackifiers such as the higher unsaturated cyclic ketones and hydrogenation products thereof, some unsaturated hydrocarbons and ketone-aldehyde resins may be present, in addition to fillers, e.g. carbon black, and pigments. Compositions containing the usual vulcanizing agents may be vulcanized at temperatures of 50 DEG  to 200 DEG C.  Specification 595,721, [Group IV], is referred to.