RECYCLING GARDEN HOSES
When plasticizers are added to PVC (polyvinyl chloride), it becomes the perfect material for floor coverings, automotive dashboards and garden hoses. But recycling such PVC components presents a challenge: in order for them to be used again in the original application, they must be ground up into a fine powder. The motor’s electrical energy converted during the grinding process causes a temperature increase that bonds the soft PVC parts – thereby rendering fine grinding impossible. But this problem can be solved by using cryogenic liquid nitrogen or carbon dioxide. By cooling the process down and embrittling the starting material, they enable fine grinding.
And these gases also perform another function as well: their low temperatures help to separate the different components from one another – in the case of a garden hose, that means separating the soft PVC from the reinforcement mesh. The final granulate in the form of soft PVC pellets is subsequently ground even finer and sifted, leaving behind a pure, high-quality PVC powder that can then be reused as a raw material – to make new garden hoses, for example.
