Powder coating is a dry finishing process. Most often associated with metal parts, it uses finely ground particles of pigment and resin, which are electrostatically charged, then sprayed onto a part to be coated. The charged particles adhere to the parts until melted and fused. If everything is done right, it forms a tough, even coating through the application of heat and energy.
Advances in the coating powders coating have lead to increasing use of the process on wood, according to the Powder Coating Institute. The timing is fortunate, especially in the business furniture arena, where designers are moving away to more rounded corners and contoured edges, with interior circles and ellipses to allow computer cords to drop through - hard to lamainate or edgeband conventionally.
Powder application also has the advantage of being a one-step finishing process, not requiring successive coats or a long time to dry.
But the heat and energy required for curing, is what makes powder coating wood a complicated process, with both the substrate, and the moisture in it, affected by the heat energy. It must be carefully controlled lest the wood get too hot.
At IWF 2014, IGP North America introduced IGP-RAPID, a ultra-low temperature powder coating of for wooden materials such as MDF,
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high density fiberboard (HDF) and natural woods such as oak and ash. The lower temperature limits (less than 250̊ F) break the limits that many powder coaters have run up against. IGP's parent firm in Wil, Switzerland, has been making powder coatings for more than 45 years. After IWF the company expanded its U.S. operations, which recently relocated to Louisville.
The highly reactive coating powders in the IGP-RAPID line allow an accelerated cross-linking process, explains IGP, while curing temperatures are low enough to protect thermally sensitive substrates.
Products made from MDF are particularly compatible with powder coating, which as a finishing method offers freedom of design, and provides the ability to choose a wide range of colors. IGP has just introduced a wider spectrum of colors for its IGP-Rapid complete line (described below).
The ability of powder to pentrate and cover narrow edges and surfaces in a single step is another advantage. And once cured, the coated surfaces are resistant to abrasion and moisture.
IGP also notes that powder coating eliminates varnishes containing solvents and VOC-based substances (volatile organic compounds).
IGP has two RAPID lines:
Single-coat: IGP-RAPID complete 88 This has a single-coat composition with extremely short curing times that has both the flexibility of a primer and the high chemical and mechanical resistance of conventional top coats.
Two-coat system - Made up of a primer that compensates for the organic properties of the substrate, and a decorative and functional top coat with good chemical and mechanical properties. It consists of:
IGP-RAPID primer 13 a highly reactive primer is used for optimal preparation of MDF substrates before coating with IGP-RAPID top 38. Its glossy surface provides the material for good adherence of the next coating while also enhancing film flexibility should the MDF warp or swell.
IGP-RAPID top 38 Tis surface finish has a very fine, matte surface structure that can be adjusted in a colorful range of shades. It is for the final coating of MDF that has already been precoated with IGP-RAPID primer 13.
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