Cold rubber, or cold polymerized rubber, is
synthetic rubber
A synthetic rubber is an artificial elastomer. They are polymers synthesized from petroleum byproducts. About 32-million metric tons of rubbers are produced annually in the United States, and of that amount two thirds are synthetic. Synthetic rubbe ...
(especially,
SBR and
NBR) emulsion
polymerized
In polymer chemistry, polymerization (American English), or polymerisation (British English), is a process of reacting monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks. There are many for ...
at a relatively low temperature.
The polymerizing temperature is approximately 5°C in the case of SBR and 5~10°C in the case of NBR.
Since rubber molecule types have a smaller number of branches than hot rubber polymerized at high temperature (50°C) and are characterized by good
stereoregularity
Tacticity (from el, τακτικός, taktikos, "relating to arrangement or order") is the relative stereochemistry of adjacent chiral centers within a macromolecule. The practical significance of tacticity rests on the effects on the physical p ...
, cold rubber has superior processability as well as the ability to produce
vulcanized
Vulcanization (British: Vulcanisation) is a range of processes for hardening rubbers. The term originally referred exclusively to the treatment of natural rubber with sulfur, which remains the most common practice. It has also grown to include ...
materials with good
tensile strength
Ultimate tensile strength (UTS), often shortened to tensile strength (TS), ultimate strength, or F_\text within equations, is the maximum stress that a material can withstand while being stretched or pulled before breaking. In brittle materials ...
, expansion and aging resistance, and flex resistance.
Except some SBR and NBR used for special purposes, most SBR and NBR available in the market are considered cold rubber.
{{rubber
Rubber
Elastomers