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.
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. The entire curing reaction is illustrated as follows:
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.
Characteristics of polyurethane powder coatings
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 object to be coated is good, and generally no primer is required.
3 The coating preparation range is wider than 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 The coating has excellent physical and mechanical properties and chemical resistance after film formation.
5 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.
The biggest disadvantage of polyurethane powder coatings is that when the film is solidified in the oven, the sealant is released, causing pollution to 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 sealant and reduce the emission of the atmosphere, while considering the use of non-toxic sealers.
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Label: Discussion on the composition and characteristics of polyurethane powder coating
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Residential Sectional Garage Door
A typical version of an overhead garage door used in the past would have been built as a one-piece panel.The panel was mounted on each side with unequal parallelogram style hinge lifting mechanism. Newer versions of overhead garage doors are now generally built from several panels hinged together that roll along a system of tracks guided by rollers. The door is balanced by either a torsion spring system or a pair of extension springs.A remote controlled motorized mechanism for opening garage doors adds convenience, safety, and security
• Aluminum garage doors are low-cost, light, rust-proof, and feature low-maintenance. They are prone to denting because aluminum is not strong and they are energy-inefficient since aluminum is a highly conductivematerial.
• Fiberglass and vinyl garage doors are composite units, combining a steel core behind a fiberglass or vinyl skin. They have also polyurethane insulated base sections, or other type of foam insulation. These premium doors can match steel garage doors, and be a realistic imitation of wood (namely fiberglass units), but they may be more expensive than steel units.
• Steel doors have become common and are available in a variety of sizes and styles, provide strength and security, are cost-competitive, and may have optional insulating value. Extra strength is available with two or three layers of galvanized steel with a low gauge number (23-24 gauge steel panels).
• Wood garage doors offer aesthetic appeal, but they are high-maintenance and may be expensive. Low-priced wood garage doors may warp and break easily.
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