Magnetic cards encode information on small magnetic strips built into rectangular pieces of plastic. They are an extremely common sight, being used for credit cards and debit cards as well as gift certificates, ID and rewards-plan cards. They are small, cheap and fairly durable. Although gradually being replaced by cards using computer chips, magnetic cards will be around for some time yet. These cards are made of twp plastics, each coming in two basic types.
Polyvinyl Chloride Cards
Polyvinyl chloride (PVC) is the most common material used for ID and credit cards. It is an extremely common polymer developed in Germany in the 1920s. It is most known for its use in plumbing pipes, but is also used in hundreds of other products such as raincoats, food containers and artificial limbs. PVC is a thermoplastic, meaning that heat softens it and allows it to be be easily molded into shape. The addition of chlorine gives PVC flame-resistant qualities that make it commonly used as insulation for electrical wires.
Acrylonitrile Butadiene Styrene Cards
Acrylonitrile butadiene styrene (ABS) is a plastic used to make some smart cards. It is made up of 50 percent styrene and varying percentages of butadiene and acrylonitrile. It used to fill the middle of the polymer price range between commodity plastics such as polystyrene and the more expensive thermoplastics like polyurethane, but has come down in price enough to crowd some of the lower-end plastics off the market. ABS is a thermoplastic that is normally formed by injection molding.
Laminated and Embossed Cards
Credit cards, debit cards and some rewards cards have numbers that are raised above the surface of the card. This is done by printing the colors onto the card first, laminating it, then heating the card and pressing the numbers in with a punch. This technique can be used for both basic types of plastic cards, since both PVC and ABS are thermoplastics that are malleable when heat is applied.
Flat Laminated Cards
Many magnetic cards are not embossed. This category includes most ID cards, gift cards, and rewards cards. All of these are made of either polyvinyl chloride or acrylonitrile butadiene styrene, then run through printers and laminating machines that coat them in clear protective layers of the same plastic.
Joshua Smyth started writing in 2003 and is based in St. John's, Newfoundland. He has written for the award-winning "Cord Weekly" and for "Blueprint Magazine" in Waterloo, Ontario, where he spent a year as editor-in-chief. He holds a Bachelor of Arts in political science and economics from Wilfrid Laurier University.