…When It’s Mechanical
Virgin plastic means that the resin used in the manufacturing process of plastic sheet, rod, or tube has never been used before – fresh out of the gaylord and fresh off the truck from the resin manufacturer.
Gaylord Of Plastic Resin
The resin is sent to a converter who pours the resin into a machine that heats it up and squishes out through a press or die, much like you did with plasticine as a kid. As in the picture below, the sheet is made bigger than actually required so that it can be cut square and true much like trimming a cake.
These “left-overs” are then reground back into small resin-sized pieces and recycled into plastic sheet but it can’t be called virgin anymore because it’s been processed at least once. This grade is referred to as mechanical or regrind. Providing the manufacturing process is clean then the reground product has virtually the same properties as virgin material but it’s not virgin.
In materials like UHMW the reground material is often mixed with differing colours to create a uni-blend or marbled look differentiating it from the virgin material. Mechanical grade polycarbonate appears more milky (less translucent?!?!) then virgin polycarb. Mechanical grade Teflon has a grey tinge to the material and attracts dust giving it even a dirtier look but it’s still Teflon.
Not all plastics can be reground because of the thermal nature of the material – you can only use it once and then it’s off to the landfill (refer to my article on recycling.)
If you have a spec that requires virgin material then this requirement should be on your purchase order and you can always request a Certificate Of Compliance (CofC) to verify the grade of the material, too.