There have been 3 basic shell compositions over the last 80 years in the game. Brunswick introduced the hard rubber ball and it became the standard in the game for over 30 years. Around 1960 Brunswick, and Columbia ( then a fledgling company in Ephrata Washington ) introduced a polyester plastic shell ball.
The plastic became a significant factor as lane finishes were getting increasingly harder and urethane lane finish replaced lacquer around 1970. About this time Don Johnson became a force on the PBA tour using a Columbia polyester ball, and in no time everyone was throwing the plastic balls, with hard rubber relegated to the background.
In 1980 AMF introduced the first urethane ( technically polyurethane ) ball, the Angle. While, technically speaking it too is a form of plastic, the friction characteristic of urethane compared to polyester were different, especially if the shell was roughed up. Urethane balls soon replaced polyester in much the way polyester replaced hard rubber as the ball of choice.
In 1991 it was discovered that enhancing urethane with resin additives changed the friction characteristics in an even more useful manner than was the case for pure urethane. Once again the landscape changed as resin became the gold standard for bowling ball shells.