Recycling Rubber History

Recycling of industrial rubber is almost as old as manufacturing of industrial rubber itself.

Way back in 1820, Charles Macintosh, soon after he started making raincoats with rubberized cloth, needed more rubber than he could import. Thomas Hancock, his research partner came up with a solution. He developed a machine which can grind up scraps of rubber produced during the raincoat-making process. These scraps were then mashed into larger rubber blocks which could be fed back into the manufacturing process. The machine to this job was called �A masticator� or "pickle" because it essentially chewed the rubber scraps into smaller bits. However, the days of easy rubber recycling, were short-lived.

The process of vulcanization which made much of the modern rubber industry possible also makes rubber recycling more difficult. Once it has been vulcanized, rubber cannot be melted back down and formed into a new product. This is because vulcanization links all the molecules in a rubber product into one big molecule that will not flow apart so easily.

In the 20th century, recycling still made strong, short-term economic sense because rubber, natural or synthetic, was expensive. In 1910, an ounce of rubber was bought at the same cost as an ounce of silver. That is one reason for which the average recycled content of all rubber products was over 50 % well into the 20th Century. By 1960, however, the recycled content of rubber products went down to an average of 20 %. This is because cheap oil imports and the increasing use of synthetic rubber brought manufacturing costs down. The development of steel-belted radial tires by 1960s would just about finish off the rubber recycling industry. This is because it made slicing and grinding tires for rubber prohibitively expensive.