Method of manufacture of styrene-butadiene latexes

A method of manufacture of a styrene-butadiene latex comprising:

• manufacturing a core latex of styrene-butadiene polymers having a gel content of 80% or less through emulsion polymerization with a chain transfer agent;
• adding monomers and the chain transfer agent to the core latex when a conversion ratio in the manufacturing of the core latex is 55 to 95% to polymerize monomers on the core latex through emulsion polymerization to prepare shell polymers, wherein a number of shell polymers is two or three;
• and
• adding the chain transfer agent alone for 30 min to 2 hr when a conversion ratio of an outermost layer is 60 to 95% during a polymerization step of the outermost layer of the shell polymers to select a gel content and a molecular weight of the outermost layer of the latex and then additionally polymerizing under 80 to 90° C. to prepare the styrene-butadiene latex having the conversion ratio of 98 to 100%,
• wherein the chain transfer agent is one or more selected from the group consisting of n-dodecyl mercaptan and t-dodecyl mercaptan.