| 1、Treatment of base materials ① Descaling, sand-blasting, brushing and chemical treatment; ② Oil removing, thorough cleaning, to be uncontaminated; ③ Do solvent infiltration treatment to form solvent film. |
4、Matters need attention ① PPS coating is non-aqueous paint, and the moisture content of solvent must be controlled lower than 0.3%, or else it is hard to reach the qualitative index; ② If the ethylene glycol is applied as solvent, the moisture content should be strictly controlled (for the ethylene glycol is very easy to absorb water in air); ③If the coating is caking, it should be stirred sufficiently to disperse. When it is needed, grinding miller could be used to grind the coating at size less than 2μ; ④ Base materials should do Oil removing and thorough cleaning to be uncontaminated; ⑤Let the solvent volatilize sufficiently around its boiling point when solidified (notice ventilating; don’t volatilize solvent under closed condition. It is dangerous to explosion!) ⑥Coating thickness of each time should be not above 150μ, and the total thickness not above 500μ. It is too thick of coating to guarantee the quality; ⑦ The rest of coating prepared should be stored and sealed. | |
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2、coating preparation ① Dry PPS powder under 120 for 6 hours; ② Mixing to prepare suspension by ethylene glycol or diphenyl oxide-ethanol solvent; ③ Solid content of suspension is 10 - 40% (depend on ejection gun and spray coating pressure); |
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| 3、Operation of coating ① Thickness of first coating <150 μ; ② Heat preservation for 5 -10 minutes at 5-10℃ lower than the boiling point of solvent; ③ Heat preservation for 5 -10 minutes at higher than the boiling point of solvent; ④ Heating up to 320-380℃ to solidified about 20-60 minutes; ⑤ Fast cool-down to lower than 130 ℃ in room condition； ⑥ Repeat 1-5 steps for several times till the coating thickness meet the requirements. |
Notices for applying PPS coating grade resin
| 1、 The additive filler is needed, and grain size should be less than 45μm, and 2 μm is optimized. |
5、The workpiece should be horizontally placed when static solidified is applied. | |
| 2、 The quality of all the filler and pigment should be guaranteed. The content of halide, sulfate and other soluble matter should lower than 5ppm. | 6、 After the finish of superficial layer solidified, the temperature should be reduced to 250℃ at speed of 1 ℃ per 1 minute, and quickly cooled down to 100℃, then do natural cooling to room temperature. By the treatment process, the resistance to impact and wear is good. | |
| 3、The fillers of base and superficial coat are different. The adhesivity of base coating and smoothness of superficial coating should be considered. It is always one base and one superficial coating for common use. It is better to have two layer of base coating. For the product with resistance of chemical corrosion, the base coating should be at least four layers. | 7、After treatment of oil moving and cleaning, the workpiece should be working as quickly as you can, in order to prevent the oxidation by air and floating dust contamination. | |
| 4、The solidify temperature of base coating is 320-340℃, and that is 360-370℃ of superficial coating. The time is controlled as 30-50 minutes for each operation. As the types and amounts of added filler are different, the solidify temperatures have great difference. It should be pay more attention to when trial produce are carried out. | 8、After spray coating, the heat solidification should be carried out when the water are volatilize or at room temperature for long time. | |
| 9、When preparation of coating, it is better to use small amount of ethanol or ethylene glycol to wet PPS resin, and then dilute the pasty mixture with de-ionized water for easy operation. |
