From www.wisegeek.com - See link below.
Nitrile gloves are made of synthetic latex. They contain no latex proteins and offer excellent resistance to punctures and tears. Nitrile gloves are three times more puncture resistant than rubber and can be used to offer superior resistance to many types of chemicals.
Unlike other latex gloves, nitrile gloves have low resistance to friction and are very easy to slide on. There are a few other reasons that nitrile gloves are more popular than other latex or vinyl gloves, including a higher degree of flexibility and superior solvent resistance. When choosing a glove, there are a few points to consider. You should consider how much protection you need, the glove's quality and how it is made, and whether you have any allergic reactions to the glove’s material.
In the manufacturing process of latex, vinyl and nitrile gloves, there are standard measurements applied to the gloves. In order to rate the protective qualities of the glove, they are graded from 1 to 3. The glove that receives a medical grade means that it has received the highest protection rating. These gloves are rigorously tested to pass FDA requirements.
The next grade is the high-risk category. These are used in the emergency medical service fields, such as paramedics. A very high level of testing is required in order to assure the proper requirements are reached.
The next level is the utility grade. These are not intended to be used in the medical field and they are not tested to any FDA specifications. However, these gloves are recommended for jobs that require hand protection, such as painting. The American Society for Testing and Materials (ASTM) regulates the standards of utility grade gloves.
In nitrile gloves, powder such as cornstarch is added in order to make putting on the gloves as easy as possible. Nitrile gloves come in a variety of sizes to fit all hands, from extra small to extra large. Nitrile gloves can be made in a variety of textures, cuff lengths and thickness. Nitrile gloves should not be stored under excessive light or heat as that can make the rubber disintegrate more rapidly.
http://www.wisegeek.com/what-are-nitrile-gloves.htm
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