Analysis of the composition and characteristics of polyurethane powder coating

As a kind of powder coating, polyurethane powder coating has many excellent properties. Its coating film has high gloss, excellent decorative performance, strong abrasion resistance, good adhesion, and good weather resistance, corrosion resistance and electrical properties. And mechanical properties, it can be said that it takes into account the advantages of epoxy and acrylic powder coatings, and has a non-toxic advantage over pure polyester powder coatings. The powder coatings can take advantage of many applications in the industrial, agricultural, transportation and aerospace industries.

First, the composition of polyurethane powder coating
The polyurethane powder coating is prepared by mixing, melting, extruding and pulverizing a hydroxyl group-containing polyester resin and a blocked isocyanate Curing Agent as a base material, a leveling agent, a pigment filler and the like. The isocyanate in a closed state when the coating is baked is released and released for curing.

Second, the composition and characteristics of polyurethane powder coatings
The isocyanate can react with any active hydrogen-containing compound, in addition to the above-mentioned hydroxyl group to form a carbamate, it can also form an amide with a carboxyl group, and form an amine, urea, and a condensate with water, an amine, a urea, a carbamate, and an amine, respectively. Diurezoate and acyl urea.

Third, the characteristics of polyurethane powder coating
In addition to the general properties of conventional general-purpose powder coatings, polyurethane powder coatings have the following characteristics:
1. When the powder coating is melted and leveled, the melt viscosity is low and the coating film has good leveling property. In particular, the sealant does not undergo a chemical reaction prior to deblocking, so that the coating has sufficient leveling time to easily obtain a smooth smooth coating film.
2, the adhesion to the coated object is good, generally do not need to apply primer.
3. The coating preparation range is wider than that of pure polyester powder. By changing the resin structure and hydroxyl value and the content of the closed polyurethane resin, powder coatings with different performance requirements and curing speed can be prepared, and the color matching performance of the powder coating is good.
4. Excellent physical and mechanical properties and chemical resistance after coating film formation.
5. The aromatic isocyanate curing powder coating has good corrosion resistance and is suitable for indoor use; the aliphatic isocyanate curing powder coating has good weather resistance and is suitable for outdoor high decorative use.
6. The paint has good workability and is mainly constructed by electrostatic powder coating.

A major disadvantage of polyurethane powder coatings is the release of a blocking agent when cured into a film in an oven, causing contamination of the ambient atmosphere. In addition, when the coating film is too thick, pinholes or bubbles are easily generated due to release of the blocking agent. To this end, it is necessary to minimize the amount of blocking agent and reduce the emission of the atmosphere, while considering the use of non-toxic blocking agents.

Anticorrosion Pigments, Inkjet Receptive Coating, Matting Agent