Well into the Twentieth Century, children were still inflating pigs’ bladders to use for a kickaround in the park. Before plastic, professional footballs consisted of an inflatable rubber bladder, a cotton lining and a stitched leather cover. Different plastics have improved each element of the modern football – culminating in the Telstar 18 that will be used in this summer’s World Cup.
The Laws of the Game
The official FIFA rules are laid out in the periodically revised Laws of the Game. The qualities and dimensions of a football are laid out in section two. The ball is defined as spherical and “…made of leather or other suitable material.” Then minimum and maximum figures are given for circumference, weight and pressure inside at sea level. The ‘other suitable material’ clause has really come into its own in the last half century.
Butyl Rubber Bladder
Butyl rubber (a copolymer of isobutylene and isoprene) is a stretchy sticky plastic that is used for the inflatable bladders that give a modern football its tough airtight innermost layer. It’s a versatile plastic also used for bicycle tyre inner tubes, chewing gum and the plastic explosive C-4. The old rubber bladders frequently burst when kicked too hard. This has not been a problem since the introduction of butyl rubber bladders.
The lining of a football sits between the bladder and the outer cover. Cheaper footballs with thin linings will quickly lose their shape. Polyester has replaced cotton as the lining of choice because cotton fibres break down faster than their synthetic replacement. A ball with several layers of polyester lining will keep its shape longer.
Polyurethane Synthetic Leather
Balls with an outer layer made from Polyurethane or Polyvinyl Chloride have been around since the 1960s. To begin with, most footballers still preferred a leather ball. However, as the quality of synthetic leathers improved, the plastic balls were able to match their leather counterparts for bounce and durability. In one department – absorbency – plastic balls were an improvement over leather. When playing in wet weather, leather balls would absorb water and become heavier. Plastic balls did not have this problem.
Over the years plastic has gradually replaced every component of the traditional football. The modern sport never has to deal with soggy balls and exploding bladders and that can only be a good thing.
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