Abstract A cold rubber is prepared by copolymerizing a butadiene and a styrene in an aqueous medium in the presence of a modifier comprising a mixture of at least two of the following: nonyl, decyl or undecyl mercaptans which are secondary or tertiary in structure and wherein, in the case of a binary mixture each of the mercaptans is present in an amount, in the mixture, of at least 10% and, in the case of a tertiary mixture in amount of at least 5%. The modifier may be used in amount from 0.05 to 0.5 parts per 100 monomers, preferably at 15 to 50 DEG F. and may be a mixture of decyl and undecyl mercaptans in a ratio of 10:90 to 90:10, preferably equal parts. The modifier may be contaminated with an olefin while a tertiary mixture of nonyl, decyl and undecyl mercaptans in a ratio of 10:45:45 may be used. The usual polymerization ingredients, e.g. catalysts p-methane hydroperoxide, cumene hydroperoxide and phenylcyclohexyl hydroperoxide, rosin soap, sodium sulphonate dispersent, sequestrant, iron sulphate, potassium perphosphate and sodium phosphate may be present as may also other modifiers. Specification 625,647 is referred to.
IN THE PROCESS OF PREPARING A COLD RUBBER POLYMER BY COPOLYMERIZING A BUTADIENE AND A STYRENE IN AN AQUEOUS EMULSION SYSTEM, THE IMPROVEMENT WHICH COMPRISES MODIFYING SAID POLYMERIATION WITH A MERCAPTAN MIXTURE CONSISTING OF DECYL AND UNDECYL MERCAPTAN, AND WHEREIN SAID MERCAPTANS ARE SECONDARY AND TERITARY ISOMERS AND ARE PRESENT IN AN AMOUNT SUFFICIENT TO LIMIT THE MOLECULAR WEIGHT OF SAID POLYMER TO A PLASTIC WORKABLE MASS, SAID MERCAPTAN MIXTURE BEING PREPARED BY THE REACTION OF HYDROGEN SULFIDE WITH AN OLEFINIC POLYMER SELECTED FROM THE GROUP CONSISTING OF POLYMERS OF PROPYLENE, BUTYLENE, AMYLENE AND MIXTURES OF SUCH OLEFINIC POLYMERS.
Claim 2
Dependent Claim
99 words
IN THE PROCESS OF PREPARING A COLD RUBBER POLYMER BY COPOLYMERIZING A BUTADIENE AND A STYRENE IN AN AQUEOUS EMULSION SYSTEM, THE IMPROVEMENT WHICH COMPRISES MODIFYING SAID POLYMERIATION WITH A MERCAPTAN MIXTURE CONSISTING OF DECYL AND UNDECYL MERCAPTAN, AND WHEREIN SAID MERCAPTANS ARE SECONDARY AND TERITARY ISOMERS AND ARE PRESENT IN AN AMOUNT SUFFICIENT TO LIMIT THE MOLECULAR WEIGHT OF SAID POLYMER TO A PLASTIC WORKABLE MASS, SAID MERCAPTAN MIXTURE BEING PREPARED BY THE REACTION OF HYDROGEN SULFIDE WITH AN OLEFINIC POLYMER SELECTED FROM THE GROUP CONSISTING OF POLYMERS OF PROPYLENE, BUTYLENE, AMYLENE AND MIXTURES OF SUCH OLEFINIC POLYMERS.