Visual effect: Streaks of yellow or dark yellow to almost brown stains after glove has been handled by hands.
Pure rubber is a translucent material that is sensitive to copper and copper alloys like brass. The transfer of these copper ions into rubber will impart a staining effect, which will be more highly apparent in thin films compared to thick rubber blocks.
Gloves being a thin product is susceptible to copper staining and if a material like Titanium Dioxide which is a whitener is added, this effect is enhanced visually. The material composition of surgical glove is also a factor and the purer the latex, the faster staining occurs as compared to high filler gloves like household gloves and some examination gloves that containe a much higher non-rubber material filler.
This staining occur when the wearer’s hands are contaminated with copper ions or molecules, for example after handling keys, copper alloy pens or coins, etc. A wet or sweating hand will accelerate the staining process as a liquid medium helps molecular transfer.
Copper staining does not impair nor reduce the effectiveness, the tensile properties and the ageing properties of the gloves. It is more a visual effect. It also does not in anyway deteriorate the material properties of the gloves.