What is Polyisoprene?
When vulcanized, gloves made from synthetic polyisoprene have rubber-like properties. They are very similar to Natural Rubber Latex (hereafter NRL). Synthetic polyisoprene is a mix of trans-1,4 and cis-1.4 polyisoprene. It can be made into an oil to be used for glove dipping. Synthetic polyisoprene, unlike natural latex (cis-1.4 polyisoprene), is stabilized using surfactant and does NOT contain natural latex proteins. Persons who are sensitive to natural latex proteins will not be allergic to synthetic polyisoprene.
Modifications to the reaction procedure for synthesized polyisoprene can alter the properties of synthetic polyisoprene. These modifications control the number of cis-and trans-isomers that are formed during the reaction, which can affect the polymer’s performance. Although synthetic polyisoprene is similar in structure to natural latex and produces a very soft examination glove, its tensile strength does not match that of natural latex.
Synthetic polyisoprene gloves are very soft and have a reasonable tensile force (depending on their polymer composition). They also offer excellent resistance to viruses and other blood-borne pathogens. These qualities make synthetic polyisoprene gloves an excellent choice for medical surgical gloves.
Synthetic polyisoprene gloves are less resistant to oil, fat, and hydrocarbons than some synthetic alternatives. Polyisoprene latex gloves might not be suitable for certain applications. An alternative glove option may be better for applications where oil, fat, and hydrocarbon exposure could occur over a longer time.
NRL proteins are not present in synthetic polyisoprene. Glove wearers don’t need to worry about being sensitive to NRL proteins, or having a Type I allergy.
Synthetic polyisoprene gloves have a soft, flexible feel that provides a glove user with excellent tactile sensitivity. Because it is a synthetic version of NRL, polyisoprene gloves share many of the same characteristics as NRL. After being stretched, polyisoprene gloves show full recovery (full elasticity). If polyisoprene gloves have been worn for a prolonged period, full recovery can lead to hand stress and fatigue. Some synthetic gloves made from nitrile, unlike polyisoprene or NRL gloves, exhibit a property known as stress relaxation. A glove with stress relaxation will relax when it is placed on the hands. This creates a very comfortable fit. These synthetic gloves are very comfortable and can be worn for a long time without fatigue or stress. This feature is important in situations where the glove is used for longer periods, such as clean room and dental environments.
Like NRL, polyisoprene is a linear-shaped polymer. This means that it must undergo a recurring step before being able to dip and form a glove. Inherently, synthetic latexes like nitrile are cross-linked during manufacturing so it doesn’t require any pre-curing to increase its strength. This is a potential advantage in the manufacturing of synthetic polymers.
Due to the manufacturing process, some polyisoprene emulsions are extremely stable. It can be difficult to use polyisoprene with a mold-dipped process because of its high stability. To process polyisoprene using natural or nitrile gloves dipping equipment, it is necessary to modify the process and formulate the formula.
Polyisoprene is safe for the environment because it does not contain nonylphenol ethoxylate surfactants (NPE), which can cause toxicological problems in water and wastewater streams. PVC gloves can also be made from polyisoprene, but gloves are free of plasticizers. PVC gloves can allow food and other materials to get into gloves made of polyisoprene. Because it does not contain acrylonitrile nor chlorinated compounds, no CN or chlorinated substances should be produced in the incineration polyisoprene gloves.