O-Rings with minimal or no softeners offer water tight sealing technology

O-Rings with minimal or no softeners offer water tight sealing technology

O-Rings with minimal or no softeners offer water tight sealing technology

Drinking water is a precious commodity and making sure as little as possible is lost from water systems is a design priority. Domestic water pipes must now be guaranteed watertight for 50 years.Leading seal manufacturer and developer Busak+Shamban have met the challenge of helping ensure that connections retain their integrity for this period.


Still today, 70% of the world’s population do not have access to clean drinking water. With the number of people in the world predicted to reach 7 billion in 2015, the development of water systems as
quickly as possible that are virtually leak free is a constant priority, especially in Asia. Even in countries with established water systems, wastage is a major concern. For instance, in the UK,
defective pipes dating back to the 19th Century mean that 24% of potable water is lost.


To effectively seal water systems, sealing materials must meet a complex mix of requirements made more demanding by the fact that almost all pipes are now plastic and there is an increasing use of
quick fit connections to speed installation. This and the required minimum integrity of 50 years that is demanded of water systems, led Busak+Shamban to put their sealing materials through rigorous
testing.


In tests, Busak+Shamban engineers simulated likely conditions within water systems, to develop a range of sealing materials and coating technologies, offering the optimum product for potable water
applications. As cost is a priority in infrastructure sealing, however, the focus was not just on performance but also economic seal production.


The only economic way of producing O-Rings for infrastructure sealing applications is by injection moulding. To make O-Ring materials suitable for this process, softeners are added to the elastomer.
These improve flow characteristics of the material into the injection mould, giving better fill, increasing seal output and making production costs lower.

These softeners though mean that injection moulded seals are not effective long term when fitted into plastic pipes. Over time, a reaction occurs and softeners tend to migrate from the seal to the pipe. The result of this is that the plastic parts might become brittle.

The challenge for Busak+Shamban was therefore to develop an elastomer compound that contained minimal softeners yet still allowed economic and efficient injection moulding of O-Rings.

After extensive research and testing, two compounds proved to have the desired flow characteristics for moulding and virtually no or zero softeners. EPDM E7518 has limited softener content while E7575 contains no softeners at all.

With these two materials giving almost universal compliance to international drinking water and food approvals, they have been well received by the water system infrastructure industry. O-Rings of both these materials are now being fitted in plastic pipes worldwide, ensuring long term sealing integrity.