Visitors to Las Vegas or other major resorts may have seen swimming pools with built-in tables for games such as poker. So, how do they play poker in a pool, without the playing cards becoming soggy? Plastic cards are the answer.
Made of vinyl, or cellulose acetate, plastic playing cards were first designed for durability. Long-time Bridge players will recognize the KEM brand of playing cards, which have been the Rolls-Royce of playing cards for decades. KEM cards are printed on cellulose acetate, the same material that camera film is made of. (Back when everyone used film in cameras!)
Other plastic card brands include Royal, Copag, Modiano, and Prestige from US Playing card company. These brands all use vinyl for their card substrate.
One common way that playing cards are damaged is by players peeking at cards by bending a corner up. Paper cards tend to retain that bend, and might eventually crease or tear across the corners. Although more expensive than paper, plastic cards are quite a bit harder to bend, and resist creasing. That durability is why they are commonly used at clubs that have a lot of regular card play.
While plastic cards will withstand occasional immersion in water, they should never be put in a dishwasher or exposed to extreme heat. If they get dirty from regular handling, just rinse them off and give them a light wipe with a soft paper towel.