What is an alkyd?
To put it simply, alkyds are oil-modified polyesters. The name is derived from alcohol and acid, since alkyds are made from combining polyhydric alcohol and polybasic acid. Alkyds are modified by adding drying oils or fatty acids to the reaction mixture, which increases flexibility, allows for different drying processes, and makes them a desired ingredient in coatings. Alkyd resins are also popular because the majority of fatty acids used in them come from vegetable oils, such as soybean and linseed oils, making it a renewable source and relatively inexpensive.
Alkyd resins are classified by the “length of the oil” in the resin, which is a measure of the percentage of fatty acid in the resin – short, medium or long. Short oil alkyds contain less than 30% fatty acids, medium oil alkyds contain between 45-55%, and long oil alkyds contain more than 55%.
Distinctions between oil length is important because it signifies drying time and physical characteristics of the final product including flexibility and durability.
Short Oil vs Long Oil Alkyd Resins
Short oil alkyd resins typically have faster drying ability and produce a harder surface, so you’ll typically find them in industrial applications such as oven paint, wood primers, and traffic paint. They require heat to cure and produce a finished surface resistant to chemicals and abrasion.
Long oil alkyds are often used in architectural paints due to their ease of application and ability to dry quickly at room temperature with air and oxidation. They’re popular for flexibility, durability, and gloss retention. You’ll find long oil alkyds in marine paints, trim paints, house paints.
How can it be used?
Alkyd resins are staples in the protective coatings industry because of their rapid drying speed, high gloss factor, and reliability. Coatings made with alkyd resins are typically used on metal, wood, or concrete to protect from weather elements. Because alkyds provide a flexible coating, alkyd paints or coatings tend not to crack or chip as quickly as other paints and increase the durability and weatherability of the structures they’re used on.
What is alkyd paint? Is it an oil-based paint?
For people shopping consumer paints in the store, you’ll find alkyd paint or urethane alkyd paint on a number of consumer paint can labels and may wonder what it means or why it matters. In most consumer applications, paint is either water-based (latex) or oil-based. Alkyd paints are considered oil-based paints,
Didn’t you just finish telling me that alkyds are modified with oil?
Well, yes, but here’s the real story. Paints typically consist of three parts – a thinner, a binder, and pigment (or color). In alkyd paints, the thinner is usually or mineral spirits or some other petroleum based solvent and the binder is a synthetic resin. That resin is made using an oil, typically linseed or soybean oil, like we discussed earlier in the article, hence the term oil-based paint.
US Polymers-Accurez
This month we’re highlighting the HPP series of modified alkyd resins from US Polymers-Accurez, specifically two short oil alkyds used in industrial coatings and baking enamels.
If you need assistance finding the right alkyd, would like a sample, or have questions about supply, contact us. We can help you identify solutions and supply quantities.
HPP 8405-70 Short Oil Alkyd
HPP 8405-70 is a coconut oil, short oil alkyd resin designed for high quality baking enamels and as a plasticizer for nitrocellulose lacquers.
Applications: Designed for brush, spray, and roller applications.
- Baking Enamels
- Plasticizer for Nitrocellulose Lacquers
Advantages:
- Non-Yellowing
- Primary Hydroxyl for Fast Reaction with Urea Resin
Typical Properties
- Viscosity (Gardner) ………. ..Z – Z2
- Color (Gardner) ………………2 Max
- Acid Value …………………….10 Max
- Solids (± 2%) ……………………..70%
- Density (lbs/gal)………9.00 ± 0.15
- Solvent ……………..n-Butyl Acetate
- VOC ……………………………..320 g/l
HPP E-9886-21-75 Short Oil Chain Stopped Alkyd
HPP-E-9886-21-75 is a dehydrated castor oil based short oil chain stopped alkyd with good air-drying properties. The product dries via oxidative crosslinking and can also be reacted with a polyisocyanate in a 2 part urethane coating. The product develops early hardness, toughness and gives good adhesion along with chemical resistance. It also gives good gloss and has gloss retention.
Applications: designed for brush, spray, and roller applications
- Industrial Primers and Topcoats
- Bathtub/Tile Refinisher
- Transportation
Advantages:
- Excellent Air-Drying Properties
- Early Hardness, Toughness and Adhesion
- Early Chemical and Water Resistance
- Weatherability
- Excellent Gloss and Gloss Retention
Typical Properties
- Viscosity (Gardner) ……….. Z5 – Z7
- Color (Gardner) ………………5 Max
- Acid Value …………………….12 Max
- Solids (± 2%) ……………………..75%
- Density (lbs/gal)………9.00 ± 0.15
- Solvent ……………..n-Butyl Acetate
Recommended Driers (Based on metal solids on Resin Solids)
- Air Dry
- 0.3% Zirconium
- 0.4% Rare Earth
- 0.15% Cobalt
- 0.01% Calcium
Leave a Reply