Common plastic materials used in Injection Molding are ABS/PC/POM/PP, and other general materials, but for some special products, functional products, there are special requirements for material requirements, product developers will choose some less commonly used according to their needs。 Special engineering materials such as LCP, PPS, PEEK, etc。 Let's take a look at the features of PPS plastics:
(1) General performance of PPS:
PPS is a white, high crystallinity, hard and brittle polymer. The relative density of pure PPS is 1.3, but it will increase after modification. PPS has a very low water absorption rate, generally only about 0。03%。 PPS has good flame retardancy and its oxygen index is as high as 44%。 Compared with other plastics, it is a high flame retardant material in plastics (pure PVC has an oxygen index of 47%, PSF of 30%, and PA66 of 29%)。 MPPO is 28% and PC is 25%)。
(2) PPS mechanical properties:
The mechanical properties of pure PPS are not high, especially the impact strength is relatively low. After being reinforced with glass fiber, the impact strength will be greatly improved from 27 J/m to 76 J/m, which is increased by 3 times; the tensile strength is increased from 6 Mpa to 137 Mpa, which is doubled. PPS is very rigid and rare in engineering plastics。 The flexural modulus of pure PPS can reach 3。8Gpa, and the inorganic filler can reach 12。6Gpa and increase by 5 times。 The PPO, which is known for its rigidity, is only 2.55 GPa, and the PC is only 2.1 GPa. PPS has good creep resistance under load and high hardness; its wear resistance is high, its wear at 1000 rpm is only 0.04g, and it will be further improved after filling F4 and molybdenum disulfide; PPS also has certain self Run. The mechanical properties of PPS are sensitive to temperature.
(3) PPS thermal properties:
PPS has excellent thermal properties, can withstand 260 ° C in the short term, and can be used for a long time at 200 ~ 240 ° C; its heat resistance is comparable to PI, second only to F4 plastic, which is also rare in thermosetting plastics。
(4) PPS electrical properties:
The electrical properties of PPS are very prominent。 Compared with other engineering plastics, the dielectric constant and dielectric loss tangent are relatively low, and they have little change in large frequency, temperature and temperature range; PPS has good arc resistance. It is comparable to thermoset plastics. PPS is commonly used in electrical insulation materials, and its dosage can account for about 30%.
(5) PPS environmental performance:
One of the biggest features of PPS is chemical resistance, its chemical stability is second only to F4; PPS is stable to most acids, esters, ketones, aldehydes, phenols and aliphatic hydrocarbons, aromatic hydrocarbons, chlorinated hydrocarbons, etc. Biphenyl and oxidizing acids, oxidizing agents, concentrated sulfuric acid, concentrated nitric acid, aqua regia, hydrogen peroxide and sodium hypochlorite. PPS has good radiation resistance. In addition, PPS has better heat resistance than nylon, good dimensional stability, and excellent oil and chemical resistance。
PPS special engineering Plastic Injection Molding process
PPS can adopt the general Injection Molding machine, and the glass fiber reinforced PPS has a melt index of 50. The process conditions of PPS Plastic Pnjection Molding are: barrel temperature, pure PPS is 280~330°C, 40% GFPPS is 300-350°C; nozzle temperature, pure PPS is 305°C, 40% GFPPS is 330°C; mold temperature is 120- 180 ° C; injection pressure, 50-130 MPA. In the Injection Molding of PPS special engineering plastics, the sol temperature requirements of the Injection Molding machine are relatively high, and the mold temperature requirements are relatively high.