All balls are based on the polyester base that "plastic" balls are made of. "Plastic" is actually a misnomer, and should actually be called polyester, because that is what it actually is.
When you add certain chemical additives to the polyester base material, you get polyurethane. The chemical additives change the polyester base, and transform it into polyurethane. That name, like the name polyester, wasn't sexy enough I suppose, so it was shortened to simply urethane.
When you add MORE chemicals to the now transformed polyurethane, you give it a completely different quality. These additives are known as resins. These resins cause the polyurethane to have totally different qualities that before.
Many people refer to certain batches of old Columbia Yellow Dot balls as "bleeders". That is because some of the chemicals in the coverstock of these soft POLYESTER balls would seep to the surface, causing them to have properties not seen before. In essence, these "bleeders" were the forerunners of todays reactive resin balls, sort of like a reactive plastic.
How many different compounds can be made from the same base material is sort of like asking how many different types of cakes you can make using flour, milk, and eggs. Although the BASIC ingredients are the same, small change make a BIG difference.
Edited by Juggernaut on 6/24/2011 at 12:52 PM
