You may have noticed clothes sticking to each other when they are taken out of the dryer. During the time your clothes spend in the dryer, they undergo a lot of friction between them rubbing against each other. This causes them to exchange electrons/charges, and in the process some become positive and some negative. As they say "opposites attract”, the clothes that have positive charges stick to those carrying negative charges.

Bounce sheets were originally invented to prevent this phenomenon of clothes sticking with each other. They contain chemicals, such as stearic acid, which melt under the heat of the dryer and coat the clothes. This reduces the friction between the clothes, avoid static charge build up. Since these chemicals stay on the clothes when they are ready to wear, one must be aware of any chemical allergies they may cause. Another method is to have chemicals that become charged upon heating, but since these are loosely bound to the Bounce sheet they can float, stick to the clothes having opposite charge and neutralize them.

Thanks for the great question!