Advantages of Nylon Co-Polymers for Hose Mandrels
|Date Published||January 1, 2006|
During the production of high-pressure hoses, a mandrel is needed to provide a foundation from which a good quality hose can be produced. Nylon copolymer resins provide the mandrel with: • Excellent flexibility, particularly in diameter over 1” • Dimensional stability, to maintain a consistent diameter • Thermal stability, to maintain mechanical properties during the vulcanization process • Durability, for increasing the number of production cycles per single mandrel • Self-lubricating, for ease of hose extraction • Chemical resistance to various rubber compounds • Weldability, for attaching various lengths • The ability to be recycled repeatedly. These batch polymerized, nylon random block copolymers are available in a range of flexibility and stiffness, as well as plasticized and non-plasticized grades. The flexural modulus ranges from 13,000 to 90,000 psi and hardness from 45 to 70 Shore D. These co-polymers possess excellent melt strength, as well as a very wide processing window, making them very easy to extrude into various mandrel diameters and lengths. The mandrels are easy to butt-weld, which increases the service life of the mandrel and provides increased manufacturing flexibility. Once the mandrel has reached the end of its service life, it can be recycled and added back into the extrusion process with virgin copolymer resin for further cost savings. The copolymer’s mechanical properties do not deteriorate over time, number of mandrel cycles, or as a function of regrind addition because the flexibility is achieved from nylon copolymer chemistry and not on plasticizers alone. Nylon copolymers also retain all of the thermal advantages associated with nylons, making them resistant to the very high heat and steam requirements of the hose vulcanization cycle. Nylon copolymer chemistry is also available to help avoid or eliminate sticking between the mandrel and the hose, making mandrel extraction safe, efficient, and easy.