Permeation

A thin liner and manufacturing shortcomings lead to most permeation problems.		The potential for permeation exists in all plastic lined piping components. Many articles have been written about the rates of permeation of various chemicals through various pipe liner materials. Testing performed by resin manufacturers has been comprised of thin films, and rather non-agressive elements such as nitrogen, helium and water vapor. The results are inconclusive and cannot be directly related to the thicker liners used in the chemical industry. Test results have shown that thicker films, and increased crystallinity result in lower rates of permeation through these liners. To determine rates of permeation, long term studies for specific chemicals are needed. Pressures, temperatures and concentrations must be defined. The test liner must be defined in terms of resin, resin grade, method of processing, crystallinity, and thickness. In each case, the result will be an individual answer for a specific paramenter. Numerous variables prevent an extrapolation of results to other chemicals, resin, liners, and liner thicknesses.
A thick liner and advanced manufacturing techniques give Resisoflex hose superior permeation resistance.		Three basic process variables have a positive influence on the permeation of chemicals through pipe and hose liners: Temperature Pressure Concentration Important in limiting permeation are the following factors: Selection of proper resin Method of processing resin Liner thickness Resistoflex recognizes and understands our customer's needs for durable permeation resistant lined hose components, and maximizes resin properties to achieve this. As the molecular weight of PTFE decreases, crystallinity increases. As crystallinity increases, permeation decreases. Crystallinity is controlled during processing. Fast cooling = low crystallinity. Slow cooling = high crystallinity. Coupled with the thickest liners in the industry, our processing capabilities enable us to offer the most permeation resistant liners available.