K-Patents has released a new application note on polyphenylene sulfide (PPS) resin process. Polyphenylene sulphide (PPS) resin is a form of engineering plastic widely used as a material for automobile and electronic parts due to its outstanding chemical resistance, high-temperature stability, good dimensional stability, inherent flame retardance and good electrical properties. Typical end products comprise electrical appliance components, automotive anad industrial applications, corrosion preventive coatings, filter and filter bags, etc.
Polyphenylene sulfide (PPS) resin is made from sodium sulfide and dichlorobenzene in a polar solvent. The process medium is the suspension containing PPS and sodium chloride. In order to release volatile substances, the suspension goes through an evaporation process. Afterwards, the ionic content is being removed by repeated washing in order to prevent its interference with electrical applications.
If chloride and sodium from raw materials remain in the resin, they can lead to the corrosion of molds and functional deterioration of metal parts. Moreover, chlorine has a potentially harmful environmental impact if burned. Thus, it is of utmost importance to remove NaCl in order to produce chlorine- and sodium-free PPS resin.
The K-Patents Process Refractometer PR-23-GP measures the NaCl concentration at the outlet line of the dissolution tank. NaCl is dissolved in the solution and the PPS resin remains undissolved in the mixture. The refractometer can monitor and control the NaCl dissolved solids concentration without influence of the undissolved PPS resin.