Urethane exterior paint

What does the term "urethane" mean? How are polyurethane products different from other types?

The term urethane and polyurethane apply to certain types of binders used for paints and clear coatings. (The binder is the ingredient that holds the pigment together in a tough, continuous film, and provides film integrity and adhesion.) Urethane binders are made be reacting a compound with an isocyanate group with another group, often a hydroxyl group: R1-N=C=O + R2-OH -> R1-NH-COO-R2. The urethane polymer is also called a polyurethane. Aliphatic solvents and polymers are preferred over aromatic types in that they provide greater flexibility and exterior durability, although they are more costly. There are different types of urethane systems:

TYPE I: one-component, alkyd reacted with a polyisocyanate; this is the usual "polyurethane" varnish used in residential and commercial applications on bare or stained wood (floors, furniture, doors, etc.); offers greater toughness and abrasion resistance than do unmodified alkyds;

TYPE II: one-component, has a polymer with unreacted isocyanate in the backbone; reacts and crosslinks upon application and exposure to moisture from the air; known as "moisture cure urethane";

TYPE III: one-component, heat-cured; the polymer contains isocyanate that is chemically blocked from reacting with hydrogen donors in the product, until the heating drives off the blocking agent; used in factory application;

TYPE IV: two-component, a polymer containing free isocyanate groups is mixed at time of use with a catalyst of monomeric polyol or polyamine; has short pot life;

TYPE V: two-component, a poly-isocyanate polymer is mixed at time of use with a resin containing active hydrogen groups; limited pot life;

TYPE VI: one-component, unreactive urethane polymer in solvent solution; forms the film upon solvent evaporation, but otherwise does not change (crosslink); PUD: "polyurethane dispersion"; dispersion of unreactive urethane polymer in water; used to modify latex coatings, particularly clear coatings, to boost mar resistance.

Dupli-Color Dupli-Color BSP207 Hugger Orange Paint Shop Finish System - 32 oz.
Automotive Alt (Dupli-Color)
  • Ready to spray lacquer
  • No mixing required
  • No re-coat window
  • Easy to apply
  • This item is not for sale in Catalina Island

Columbia MO Painters: Website Available Now for Painting Contractors  — DigitalJournal.com
The website can be expanded or modified easily to suit the needs of a local residential or commercial painting company.

Rust-Oleum Rust-Oleum 244163 Porch Floor Paint, Gray Semi-Gloss, 1-Quart
Home Improvement (Rust-Oleum)
  • Scuff and scrape resistant
  • Resists fading, cracking and peeling
  • Soap and water clean up
  • Easy to apply with brush, roller or pad
  • Tests up to 3X stronger than competition in scrub resistance
Wagner Wagner Flexio 590 Indoor/Outdoor Hand-held Sprayer Kit
Lawn & Patio (Wagner)
  • Sprays an 8 ft. by 10 ft. surface in 1-5 minutes and can spray up to 8.0 gal. per hour
  • iSpray nozzle is designed without wear parts extending the usable life
  • Includes 1 year warranty
  • iSpray nozzle adjustments include horizontal or vertical and wide or narrow patterns.
  • X-Boost turbine generates 3 times the power of comparable sprayers
Wooster Brush Wooster Brush R232-9 Epoxy Glide Roller Cover, 1/4-Inch Nap, 9-Inch
Home Improvement (Wooster Brush)
  • Proprietary dark gray shed-resistant fabric for all epoxies and urethanes
  • Great pickup and release and flow for fast results
  • Green double-thick polypropylene core resists water solvents and cracking
Epifanes Epifanes Rapid Clear (750 ml)
Sports (Epifanes)
  • Semi-gloss finishproduct with long term protection and enhancement of all marine and household woods.
  • Rapid Clear provides excellent protection in all climates, interior and exterior use above the waterline.
  • Rapidclear provides an enhancing coat that bonds extremely well to teak and other oily woods
  • Rapidclear can be applied every 5-6 hours, two to three coats a day and never have to sand between coats.
  • Only four to five coats need to be applied under most conditions, then re-apply when needed. Semi-Gloss finish.
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