Solution of Poor Mechanical Properties and Chemical Resistance

polyester coating degradation

1.Poor Mechanical Properties and Chemical Resistance

Cause: Too high or Too low curing temperature or time
Solution: Confirm and check with powder coating powder supplier
Cause:Oil,grease,extrusion oils,dust on the surface
Solution:Optimize pretreatment
Cause:Differing materials and material colors
Solution:Insufficient pretreatment
Cause:Incompatible pretreatment and powder coating
Solution:Adjust pretreatment method,consult powder supplier

2.Greasy Surface(Haze like film on the surface which can be wiped off)

Cause: Blooming effect-white film on the powder surface,which can be wiped off
Solution:Change powder coating formula,increase curing temperature
Cause: Insufficient air circulation in the oven
Solution:Increase air circulation
Cause: Contamination on the surface due to incompatibility of powder coating
Solution:Use only powder coatings from one supplier.
Cause:Powder coating not sufficiently cured
Solution:Observe curing parameters

3.Lifting of the powder coat layer

Cause: Under or over curing of the powder coating film
Solution: Observe curing parameters
Cause:Insufficient/inappropriate pretreatment
Solution:Adjust pretreatment to job at hand
Cause: Scale,surface rust on the work pieces
Solution:Use “fresh” work pieces or store in dry environment ;mechanical pretreatment
Cause : Oxide layer on the work pieces,white rust on zinc palting
Solution:Use suitable pretreatment materials;Use mechanical pretreatment
Cause:Reduce film thickness or use more

4.Poor Mechanical Properties -poor impact resistance or poor flexibility

Cause: Under curing of coating film
Solution: Optimize curing parameters
Cause:Poor cleaning or preteatment
Solution: Check pretreatment and process
Cause:Film thickness too high
Solution: Optimize the thickness of film
Cause:Poor properties of powder coating material/resin
Solution:Consult with powder supplier

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