Characteristics and Application of PPS

Polysulfide diphenyl ether (PPS) of the molding process

1. Processing characteristics

PPS resin provided by the manufacturer as a relatively low quality (4000 ~ 5000), a high crystallinity (75%) of white powder, which can not be directly pure PPS plastics molding, can only be used for spraying. For plastics molding PPS, the need for cross-linking modification, the melt viscosity increased. General crosslinked melt index of 10 to 20 is appropriate; for glass fiber reinforced PPS melt index can be larger, but not greater than 200.

PPS heat cross-linking method and chemical cross-linking cross-linking of two, currently dominated by thermal crosslinking. Thermal cross-linking cross-linking temperature of 150 ~ 350, 150 lower than the cross-linking does not occur, higher than the occurrence of highly cross-linked 350, but lead to processing difficulties.

Chemical cross-linking need to be added to promote cross-linking agent, the specific varieties of zinc oxide, lead oxide, magnesium oxide, cobalt oxide, and phenolic compounds, HEXAMETHOXYMETHYL melamine amide, hydrogen peroxide, alkali metal or alkaline earth metal hypochlorite, etc..

PPS Although cross-linking, but little decline in liquidity; Thus, waste can be reused three times; PPS itself with mold release, can not join the release agent; PPS after heat treatment can improve the crystallinity and the heat distortion temperature, post-processing conditions: temperature 204 , time 30min.

2. Processing methods

(1) Injection: adopt common injection molding machine, glass fiber reinforced PPS melt index of 50 is appropriate. Injection molding process conditions: barrel temperature, pure PPS to 280 ~ 330 deg, 40% GFPPS to 300-350 deg; nozzle temperature, pure PPS to 305 deg, 40% GFPPS to 330 deg; mold temperature of 120-180 deg; injection pressure ,50-130 MPA.

(2) out of: The exhaust extruder conditions were: feed zone temperature is less than 200 deg; barrel temperature of 300-340 deg, connect the temperature 320-340 deg, the die temperature of 300-320 deg.

(3) Molding: suitable for large products, using two compression, before cooling, after hot pressing. Pressing the preheating temperature of pure PPS is about 360 deg 15min, GFPPS to about 380 deg 20min; molding pressure of 10 ~ 30Mpa, cooled to 150 deg stripping.

(4) spray forming: suspended by suspension spray coating method and mixed with the powder thermal spray are the PPS coating to the metal surface, through the plastics, quenching and by coating; PPS coating treatment temperature at 300 deg more insulation 30min.

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