In the thermosetting powder coating (HG/T 2006-2007) standard, the resistance to artificial weather aging of outdoor flat powder coatings is divided into qualified products and superior products. The requirement is that after artificial accelerated aging for 500/800 hours, the discoloration and loss of light should be less than level 2, and there should be no abnormal phenomena such as powdering, foaming, cracking, peeling, etc.

The weather resistance of powder coating film refers to the changes in color, gloss, adhesion and other indicators produced by the coating of objects under the combined effects of outdoor sunlight, rain and dew, as well as environmental temperature, humidity, atmosphere, etc. The weather resistance of its coating is related to the following convenient factors:

1. The chemical structure and dosage of the film-forming material are superior to epoxy resin after curing with polyester polyurethane.

2. Adding additives such as UV absorbers, antioxidants, etc. to improve the weather resistance of the coating

3. The influence of physical and chemical properties of pigment fillers.

The pigments used in outdoor powder coatings are related to their physical and chemical properties, particle size, and particle size distribution, as well as the pigment concentration in the formula. Generally speaking, those with coarse particle size and high color concentration have better weather resistance.

The following types of pigments used outdoors have been tested by Laisi Laboratory:

1. Red: coated molybdenum chromium red PR104, iron oxide red PR101, pyrrole red PR254,

Anthraquinone Red PR177, Quinacridone Red PR122;

2. Yellow: Coated chrome yellow PY34, permanent yellow PR139,

3. Blue: Phthalocyanine blue PB15:4, ultramarine PB29,

4. Green: Phthalocyanine Green PG7

5. Others: Everlasting Purple PV19/PV23, Orange PO36, Carbon Black PBk6/7

It is worth mentioning that zinc oxide, as a white pigment and additive, can be added with 5% in the formula, especially for indoor varieties, which have good anti-static, antibacterial, and anti powdering effects