customized OEM thermosetting powder coating manufacturer, exporter, factory

November 13,2021

Most people are unfamiliar with thermosetting powder coatings and seem to have never heard of it. In fact, whether in interior decoration or furniture refurbishment, the role of powder coatings is very large, so it is very important to choose the raw materials of powder coatings, which has a significant impact on the quality of the coating and the performance of the coating film. Today we will take a look at how to choose the raw materials for thermosetting powder coatings.

 

thermosetting powder coating

 

Selection of resin

 

The structure and performance of resin are the main factors determining the quality of powder coating and film performance. The following basic technical requirements shall be met:

 

  1. The resin for thermosetting powder coating must contain active functional groups to ensure the formation of network structure during baking film formation.

 

  1. In the process of powder coating construction, if the decomposition temperature of resin is very close to the melting temperature, it is very difficult to control the heating temperature. Therefore, the temperature difference between the melting temperature and decomposition temperature of the resin is required to be large.

 

  1. It is required that the melting viscosity of the resin is low and the range is narrow. When the temperature above the melting point is reached, the viscosity should decrease rapidly. In this way, a film with good leveling can be obtained after coating on the coated object by powder coating electrostatic spraying and fluidized bed dip coating.

 

  1. Over sprayed coatings in powder coatings can be recycled. However, some powder particles have been in contact with the air for a long time and change due to the influence of moisture and temperature, so the physical and chemical stability of the resin is better.

 

  1. The production of powder coatings generally adopts mechanical crushing method, which can obtain uniform particle size distribution and particle shape. Higher glass transition temperature and melting point should be selected for the resin to make it have better comminution.

 

  1. The adhesion of powder coating depends on resin. If the adhesion of the coating is good, there is no need to apply primer, and the durability of the coating film is good. The adhesion of thermoplastic resin is poor, so it is necessary to precoat primer.

 

  1. The color of the resin shall be light, transparent and non-toxic.

 

Selection of curing agent

 

Curing agent is an important factor in resin modification and film formation. It directly affects the quality and film properties of powder coatings. Therefore, it is very important to select a suitable curing agent, which should meet the following conditions:

 

  1. It is powder, granular or flake at normal temperature.

 

  1. Chemical and physical stability: no chemical reaction with resin or other components and no agglomeration during production or storage. When spraying construction, it can be cured quickly after baking to a given temperature, and the film is flat, smooth and plump.

 

  1. The curing agent shall be non-toxic (low toxicity) and non irritating. It shall not release peculiar smell and harmful smell during baking and film forming.

 

  1. The curing agent is colorless and cannot stain the film and affect the appearance of the film.

 

Selection of pigments

 

The pigments and fillers in powder coating components can not react with other components during production, preparation and storage, and have good stability to heat and light. Pigments for powder coatings shall meet the following conditions:

 

  1. It can be evenly dispersed in the resin.

 

  1. Good thermal stability during film curing.

 

  1. Good light stability, chemical resistance and solvent resistance.

 

  1. No color seepage, frost and migration in the film.

 

  1. The color will not change due to other components.

 

  1. Do not promote resin aging.

 

  1. In the hot melting state of the resin, the dispersion is good.

 

  1. Good coloring power and covering power.

 

Selection of filler

 

The addition of filler in the powder coating formula also has the function of modification, such as adjusting the film flatness, gloss and physical and mechanical properties. The selection requirements for fillers are:

 

  1. It is easy to disperse in the formula components and has good fluidity.

 

  1. It does not contain foreign matters affecting the quality of the film.

 

  1. No harmful chemical reaction with other components.

 

  1. Do not reduce the physical and mechanical properties of the coating.

 

  1. Do not reduce the physical and mechanical properties of the coating.

 

Does the above selection of raw materials for thermosetting powder coatings help you? Foshan Wolong Chemical Co., Ltd is one of the leading customized thermosetting powder coating OEM and manufacturer and exporter and factory in China, any interests, welcome to contact us.

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