As a decorator, I’m forever being questioned about why oil-based products yellow over time and the science of gloss paint. Things have changed dramatically over the past decade, and it doesn’t look as though the rate of change is going to slow.
But what is driving the change? Why does modern oil-based gloss turn yellow? What is the alternative? There are loads of different things in play that are shaping the landscape when it comes to gloss. I thought I’d put a little blog together and explain what’s going on.
The Science of Gloss Paint
Up until 2010, there was only really one type of gloss paint product you would have used, and that was oil-based. The problem is, the oil in oil-based gloss is an alkyd, and one of the properties of alkyds is they turn yellow over time.
Manufacturers used to use chemicals known as VOCs to slow the yellowing process of alkyd oils. However, in 2010 the EU started to restrict the use of VOCs in a bid to make paint more environmentally friendly. The knock-on effect is alkyd products now turn yellow a lot faster than they used to. These restrictions have systematically been tightened since then.
This affects white oil-based gloss more than tinted colours. However, the discolouration happens to some extent in EVERY colour.
So, what is the alternative?
Well, there is water-based, but this also comes with issues. There are plenty of great quality water-based satinwood products out there, WRX satinwood as an example, is awesome. Water-based gloss is a little trickier. You can’t get the sheen level with water-based, as the sheen would be provided by the alkyd in traditional paints. Water-based gloss doesn’t level off either. You can be left with stringy, horrible brush marks in a lot of cases.
I know water-based technology is getting better all the time as science advances, but it really isn’t there yet.
Hybrid Gloss Paints
Hybrid paint is the answer for me!! This is a technology which isn’t often spoken about. In fact, for reasons that are lost on me, paint manufacturers try to disguise hybrid products as “water-based”. This is a madness!!
Hybrid gloss is what a chemist might call an “alkyd emulsion”. It does contain a very small amount of the alkyd oil, but a lot. Certainly nowhere near the amount that you’d find in traditional oil-based gloss.
The best way I can describe a hybrid gloss is a compromise between water-based and oil-based. I’ll explain.
A hybrid gloss is mostly water-based, but with an “oil carrier”.
A hybrid gloss will level off better than water-based, but not quite as good as oil.
A hybrid gloss will yellow over time, but it will take years for this to happen.
A hybrid paint is tougher than water-based, but not quite as tough as oil.
Get the idea?
In other words, you almost avoid the issue of your gloss yellowing altogether, but without the many drawbacks of fully water-based paint.
Great examples of quality hybrid gloss paints include Teknos Futura and Johnstone’s Aqua.
What Does the Future Hold for Gloss Paint?
Gloss paint products have changed so much in recent years and the evolution of gloss hasn’t finished just yet. We are being driven by legislation and science. The same way as we are being turned away from diesel vans and pushed towards electric.
Change needs to happen because the world we live in is not sustainable. Oil-based paint products will be phased out before long. I just hope the products we are left with will perform as they need to.