Processing & Installation

Processing with FlowGuard™ PEX Resins Ensures Quality Piping

FlowGuard™ Flex 3 layer piping is produced using a silane processing method that ensures quality in manufacturing. Under this closely-controlled, two-step production process, the FlowGuard ^® silane-grafted PE (formed when silane is attached to the PE backbone) is combined with its catalyst during pipe extrusion and then exposed water. The water diffuses into the pipe and hydrolyzes the silane to produce a silanol (step 1). The silanol then condenses under the action of the catalyst to form intermolecular Si-O-Si cross-links (step 2). The resulting irreversible Si-O-Si cross-linking creates the network structure that gives pipe made with FlowGuard^® PEX its superior strength and durability.

In the FlowGuard Flex 3 layer piping solution manufacturing process, the precise amount of grafted silane is tightly regulated. This ensures that when the FlowGuard™ Flex resin is combined with the proper ratio of its catalyst masterbatch, the resulting pipe will cure to the necessary gel level for proper pipe performance every time (greater than 70 percent gel). This manufacturing process also ensures even distribution of the silane grafts throughout the PE molecules. This provides good cross-linking and, consequently, quality PEX pipe with excellent high-temperature performance and stress-crack resistance.

The base PE resin also plays an important role in final pipe properties. The base resin is engineered to provide a unique combination of flexibility and pipe performance. Through careful control of parameters such as molecular weight and molecular weight distribution, the base resin offers superior strength. Pipe flexibility is achieved through precise control of the density and crystallinity.