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DEFINITIONS

Permeation:

A process by which a chemical can pass through a protective film without going through pinholes, pores, or other visible openings. Individual molecules of the chemical enter the film and “squirm” through by passing between the molecules of the glove material may appear unchanged to the human eye.

Chemical permeation can be described in simple terms by comparing it to what happens to the air in a balloon after several hours. Although there are no holes or defects, and the balloon is tightly sealed, the air gradually passes through (permeates) its walls and escapes. This simple example uses gas permeation, but the principle is the same with liquids or chemicals.

Permeation data are presented in two values:  Breakthrough time and Rate.

Breakthrough time:

Breakthrough times (min.) are the times observed from the start of the test to first detection of the chemical on the other side of the sample (for test methodology, see the outside back cover of this guide). These times represent how long a glove can be expected to provide effective permeation resistance when totally immersed in the test chemical.

Rate:

Permeation rates are the highest flow rates recorded for the permeating chemicals through the glove samples during a six-hour test. These qualitative ratings are comparisons of permeation rates to each other.

Degradation:

Degradation is a reduction in one or more physical properties of a glove material due to contact with a chemical. Certain glove materials may become hard, stiff, or brittle, or they may grow softer, weaker, and swell to several times their original size.If a chemical has a significant impact on the physical properties of a glove material, its permeation resistance is quickly impaired. For this reason, glove/chemical combinations rated “Poor” or “Not Recommended” in degradation testing were not tested for permeation resistance.  Please note, however that permeation and degradation do not always correlate (6th Edition, Ansell Protective Protective Products Chemical Resistance Guide- Permeation & Degradation Data).

Latex:

Natural rubber, or latex is inherently elastic and resilient, plus it resists acids, alkalis, salts, and ketones. Natural rubber latex is also blended with or dipped in other polymers to achieve a combination of features, such as the abrasion resistance of nitrile with the flexibility of latex. Latex gloves are suited for food processing, electronics assembly, and laboratory chemical handling.

Neoprene:

Neoprene is a synthetic rubber developed as an oil resistant substitute for natural rubber.  It is resistant to; acids caustics, alcohols, inks, refrigerants, ketones, oils, fats, grease fertilizers, cleaners, and detergents. Neoprene gloves are used in petrochemical, degreasing, and refining, chemical processing, metal finishing, mechanical work, painting, bleaching, and commercial dishwashing.

Nitrile:

Nitrile is a synthetic rubber that is also referred to as NBR or acrylonitrile-butadiene. Nitrile gloves have superior puncture and abrasion resistance in addition to chemical protection, and they will not weaken or swell in aromatic or petroleum solvents, caustics, or animal fats.  They are suited for chemical and food processing, stripping and degreasing, motor and engine manufacturing, machining operation using cutting oil and coolants, electronics, and acid etching and chemical washing.

Norfoil:

This lightweight and flexible laminate material resists permeation by a wide range of solvents, acids, and bases. Silver Shield*gloves are often used under other gloves with chemical protective suits or when working with abrasive material.  They are useful for chemical and petrochemical laboratory work, spill cleanups, and HAZMAT control operations.

Vinyl:

Also known as polyvinyl chloride or PVC, vinyl is a plastic material that resists acids and alcohols, but not petroleum solvents. Economical substitutes in many cases for natural rubber latex gloves, vinyl gloves are used for a variety of industrial and food processing applications, intricate assembly work, laboratory research, and pharmaceutical manufacturing.