SABIC IP aims to replace metals with engg thermoplastics in water valves

16-Jan-09

SABIC Innovative Plastics' portfolio of advanced specialty materials, combined with the scientific expertise of its Netherlands-based Fluid Engineering Center of Excellence have led to use of engineering thermoplastics instead of metals to deal with static or fluctuating pressure, high temperatures and various chemicals in water valves. Compared to metal, which requires the mechanical assembly of multiple parts, thermoplastics, such as SABIC Innovative Plastics' Noryl* and Ultem* resins, allow multiple components and functions to be integrated into a single part, the company says. For instance, a smooth and chemically resistant inner surface can be overmolded with a structural external housing in one process step, saving time and money by eliminating secondary operations. According to the company, its Fluid Engineering Center tests critical material properties of resins including static strength, long-term creep displacement and strength, fatigue and water and chemical resistance targeted for use in water valves. Amorphous resins such as Noryl* and Ultem* resins typically creep less and retain dimensions and valve sealing longer than semi-crystalline resins. However, if stresses are too high the deformation may grow and result in creep rupture. There are many glass-fiber-reinforced resins that can be used to improve the creep performance of a material, for instance Ultem 2300, Noryl GTX and Noryl GFN1630V resin grades. In order to prolong life under fatigue, SABIC Innovative Plastics' Noryl GFN1430V resin can improve thin-wall performance in these types of applications. In addition, to prevent a high risk of corrosion SABIC Innovative Plastics' Noryl polyphenylene oxide (PPO) resin, while amorphous, nonetheless provides better hot water resistance than other resins with otherwise similar performance.