Patent GB-307308-A (GB)
Title: Process for the manufacture of rubber-like masses
IPC: C08F36/04
Filed: 1929-03-04
Abstract: 307,308. I. G. Farbenindustrie Akt.- Ges. March 3, 1928, [Convention date]. Caoutchouc, synthetic.-Butadiene or a homologous or analogous hydrocarbon is polymerized partially in a known manner, so that the polymerizate has not yet attained elasticity, and the polymerization is then completed in another known manner; or after the first stage of polymerization a further quantity of the diolefine is added and the polymerization is then completed in the same or a different known manner. It is stated that particular characteristics as regards elasticity and plasticity may be obtained by polymerizing butadiene by the emulsion process and then adding more butadiene and polymerizing by heat or sodium; or the butadiene may be first polymerized by heat, and then by the emulsion process. In specific examples, (1) isoprene is polymerized with sodium at 35‹ C. to the consistency of a strongly rolled crude rubber (that is to say, a viscous fluid mass); the product is dissolved in isoprene, emulsified with sodium oleate solution and polymerized at 60‹ C., the latex being coagulated in the. usual manner. (2) 2-3-dimethylbutadiene is polymerized alone at 60<0> C. to the consistency of syrup, more dimethylbutadiene is added, the mixture being emulsified with sodium oleate solution and polymerized for a week at 60‹ C., yielding a viscous cream which gives a latex with water, and is coagulated in the usual manner. Specification 29277/09 is referred to. The Specification as open to inspection under Sect. 91 (3) (a) states that butadiene may be heated to produce a strongly viscous mass, which is dissolved in butadiene and polymerized by lieat; or the polymerization may be effected by an alkali metal, more of the same or of a different alkali metal being added if desired at the second stage; or the polymerization may be effected with an emulsion, the polymerizate being dissolved in the initial hydrocarbon, and emulsified with the same or another emulsifying agent, and with the addition, if desired, of hydrogen peroxide, manganese peroxide, or another agent to accelerate the reaction, the polymerization then being completed; or butadiene may be partially polymerized by heating, an alkali metal then being added and the process completed with or without the addition of the initial hydrocarbon, or an emulsifying agent may be added in the second stage instead of the alkali metal; or the first polymerization may be effected by an alkali metal or in an emulsion and the second by heating; or the first polymerization may be effected with an alkali metal and the second in an emulsion with an emulsifying agent, some of the initial hydrocarbon being added at the second stage, with or without a catalyst if desired. It is stated that, there may be several interruptions, each followed by the addition of the initial hydrocarbon and/or by a change in the method of polymerization. Specific examples describe (1) the polymerization of butadiene in the same manner as the polymerization of isoprene in Example 1 above; and (2) butadiene is emulsified with sodium oleate solution and polymerized at 60‹ C. for 30 days to give a latex which is coagulated by cooling, separated from the emulsifying agent, and dried; the product is caused to swell in butadiene, sodium wire is added, and the mixture is polymerized for 8 days at 30‹ C. This subject-matter does not appear in the Specification as accepted.