Polyurethane paint

polyurethane paint

Top reasons to use polyurethane paint (PU coating)

It can be difficult to find the right coating; one that provides protection, durability and brilliant looks. One of the few paints to offer all those properties is polyurethane paint (PU coating). It provides an extremely durable, hard, and glossy finish, and can be modified to fit your intended purpose perfectly. Due to its flexibility, polyurethane paint is equally applicable in decorative and industrial settings. This coating has many benefits, including:

  • Extreme durability, protection from mechanical abrasion, stains and scratches 
  • Corrosion resistance (metal surfaces)
  • A flawless glossy finish which resists colour fade
  • Resistance to water, steam, moisture, and chemicals
  • “Self cleaning” – dust and dirt wash off during rain
  • Temperature resistance – suitable across a wide range of temperatures (up to 110°C)

Polyurethane is essentially a liquid plastic which dries like a paint. As a result, it is hard-wearing and resistant to damage, thus it is particularly applicable for industrial and architectural coatings. If you have ever ridden a rollercoaster, you may have admired some polyurethane paintwork.  

What is polyurethane paint?

Polyurethane paint is used on many surfaces, including car bodywork

Polyurethane paint is simply one form of polyurethane, first made in 1937 by Otto Bayer. It also comes in foams (like sofa padding), elastics, and hard plastics such as structural parts of electronics or car bumpers.

Polyurethanes are produced through a reaction between:

  • a polyol resin (known as the base)
  • a polyisocyanate curing agent (known as the hardener)

PU paint is available in water- and oil-based forms, which come in gloss, semi-gloss and satin or matte finish. They can be applied as a clear top coat, as a vibrant colour, or as varnishes and finishes for wood, metal, concrete, plastics, and even fabrics. 

How to use polyurethane paint

PU paint comes in water-based, oil-based and oil modified water-based varieties, each of which are suitable for different substrates. Using a cloth to apply polyurethane paint will give the finish an authentic “rubbed in” look, while a paint or foam brush will give a flawless glossy sheen. Polyurethane paint spray application gives the smoothest finish of all.

For exterior applications, use spar urethane. It is UV resistant and has greater weather resistance.

A polyurethane coating usually comes in a two pack system (although it is also available in a single pack), with the base and the hardener in separate containers, ready to be mixed. You should always mix only the necessary amount of the parts, to avoid waste, and watch your percentages. The two pack polyurethanes are more durable than single packs, but less flexible. Always follow the advice on the tin. 

PU paint Description Application Product example
  • Easy to apply
  • Clear finish
  • Faster drying than oil-based
  • More expensive than oil-based
  • Low toxicity, less odour
  • Not suitable for exposure to heat and chemicals
Do not apply over oil-based polyurethane. Using a fine brush, foam pad or cloth apply a thin coat, working with the grain. Wait till dry (about 4hours), then reapply. May require up to 10 coats. Rust-Oleum 6711 System water-based clear PU concrete sealer
  • Easy to apply
  • Requires fewer layers than water-based
  • More durable than water-based
  • Suitable for exposure to heat or chemicals.
  • Adds a yellowish tint
  • Higher VOC (Volatile Organic Compound) emissions
Apply using a natural bristle brush, clean cloth or foam brush. Work with the grain, using long strokes and do not over-brush. Once dry, lightly sand the entire surface (do not remove the first layer). Wipe off all dust then repeat. Continue until you are satisfied (two to three coats is usually enough). Use in a well-ventilated area, wear a mask.  Olympic Polyurethane, oil-based finish for interiors
Oil modified water-based
  • Hybrid mix of oil- and water-based polyurethane.
  • More durable than water-based
  • Low odour
  • Fast drying
This comes in wipe-on and brush-on varieties. Each require three coats, but the wipe-on is applied using a lint-free cloth, and the brush-on with a synthetic filament brush. Brush-on takes two hours to dry, while the wipe-on takes two to three hours. Minwax water-based oil modified polyurethane

Polyurethane paint for wood and metal

Much of our world is coated in polyurethane, from the car we drive to work to the floors we trudge across in the supermarket.  Polyurethane paint is especially good for coating metal, due to its anti-corrosive qualities. While metal polyurethane coating use is mostly industrial (such as the automotive industry), coatings for wood products are hugely popular among the consumer DIY and carpentry crowd.

PU coatings are commonly used because they provide the ideal combination of protection and decoration.

 A particularly popular application for polyurethane coatings is flooring. PU paint is used as a finish on wood flooring, as well as concrete in garages, apartments, or schools. Its resistance to abrasion and chemicals makes it an ideal coating for laboratory floors. 

preparing for applying PU varnish

Always wear the appropriate safety clothing when applying PU coatings

How to use polyurethane paint safely

The downside to polyurethane coatings is that they contain isocyanates which, if handled incorrectly, can pose health risks.

When working with polyurethane paints always wear a mask, gloves, overalls, goggles, and avoid contact with skin or eyes. Always read and obey the safety instructions.

Polyurethanes also release Volatile Organic Compounds (VOCs). These chemicals are irritants, causing headaches, eye, nose, and throat irritation, and dizziness. One of the benefits of water-based polyurethanes over oil-based is that it has lower VOC emissions. Like with all potentially hazardous materials, remember to take due care.

Polyurethane paint suppliers and prices UK

Prices vary across brands and products, and keep in mind that water-based polyurethanes are more expensive than oil-based. Here is an indication of the price range across polyurethane paint suppliers. Polyurethane is also available as foam for sealing and insulation.

Brand Product Price  Quantity
Coo-Var V606 Polyurethane Varnish £22 1 L
Sadolin Polyurethane Varnish for floors £40 2.5 L
 Blackfriar  Polyurethane Floor Paint  £45  5 L
Selemix 7-511 Polyurethane Matt Topcoat £70 5L
 Teamac  P101 2 Pack Polyurethane Varnish  £172  5L
Rust-Oleum 9600 Rust-o-Thane Polyurethane Topcoat £190 5 L
 Sika  Sikafloor 400 N Elastic  £294  18 Kg

Contact us to get more polyurethane coating company details and general information on polyurethane coating.

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