A piece of laminated glass includes a plastic interlayer. Find out the difference between EVA and PVB.
Laminated glass is one of the unsung heroes of the modern world.
While it looks much the same as any other type of glass, it's built with a specific purpose in mind: to withstand great force and pressure and maintain structural stability when broken.
Laminated glass saves lives, whether used for a car windscreen, walk-on balcony or glass facades in hurricane zones.
But this is only possible because of an unseen interlayer – the metaphorical butter that holds this mighty sandwich together. These thermoplastic interlayers bond the outer layers of glass, creating a single pane that's exceptionally hard to break.
When you come to order laminated glass, you may find yourself confronted with acronyms to describe this interlayer. Two common ones are EVA and PVB. What, if anything, is the difference?
To answer that question, we first need to look at how laminated glass is manufactured.
How is laminated glass made?
Laminated glass is like a sandwich. It's made from two or more panes of glass with one or more polymer interlayers between them. The outer panes can be toughened for extra durability.
They're held together by an elaborate process that begins with high-temperature pre-pressing or vacuuming and ends with high levels of heat pressure. The result? A composite glass product where the glass and interlayer are permanently bonded together.
This tough-as-nails bond means laminated glass breaks in a unique way. Unlike annealed glass, which breaks into jagged shards, or
toughened glass, which breaks into lots of tiny pieces, laminated glass stays in its frame. The only sign of damage is a distinctive spider's-web-like pattern across the surface.
This structural stability in the face of intense force and pressure makes laminated glass a superb variety of safety glass. You'll find it in overhead glazing such as skylights and canopies, internal glass partitions, shop fronts, schools, hospitals, government buildings, banks – any location where the glass has to be built like a tank.
But laminated glass and its interlayer aren't just about strength. It also provides advanced sound insulation and thermal control. This in turn makes it thermally efficient – good for the wallet and the planet.
And not one of these functionalities would be possible without an EVA, PVB or other type of interlayer.
What's the difference between EVA and PVB interlayers?
In laminated glass, EVA and PVB do the same job. But they're processed at different temperatures with different equipment and have slightly different use cases.
EVA glass laminating machines provide a low-cost, easy-to-use process. The downside is that they can't be mass-produced. PVB is the opposite. It costs more and takes longer to produce but it can be mass-produced.
PVB comes in a range of colours. This can be seen in all sorts of applications, from the "shade band" on a car windscreen to
coloured and
decorative glass products.
As well as being colourfully customisable, PVB is especially strong and durable. This makes it a go-to choice for bulletproof glass and other forms of safety glazing.
It also has a high level of UV resistance – a key reason why PVB is often used for laminated glass in skylights and conservatories. And it repels moisture and chemicals just as well as those harmful UV rays.
EVA (ethylene vinyl acetate) is a more recent invention. Its main selling point is that it's more water-resistant than PVB. However, it's less UV-resistant than PVB.
It's a soft, flexible material that's easy to handle – hence its use in the mass production of laminated glass. Some say it leads to more durable and long-lasting glass thanks to its superior bonding qualities.
Compared to PVB, EVA has a lower melting point. Like PVB, it can be used for decorative glass products such as
silk-screen printing.
Which should I choose?
Both EVA and PVB can be used in top-quality laminated glass. Your choice will depend on a range of factors. In most cases, getting expert advice from a glass processor can expedite this process.
If it's elasticity, transparency and adhesive strength you're after, EVA is the way to go. If UV resistance is your priority, go for PVB. And if high-impact resistance is the issue – in a building that needs to be bullet- or bomb-proof, say – PVB is your interlayer of choice.
What is SGP?
EVA and PVB are both types of plastic. SGP, by contrast, is a brand name standing for "SentryGlas Plus". It bonds to the outer panes of glass in the same way as EVA and PVB. Its main selling point is that it has superior clarity and extremely high levels of weather resistance.
Some estimates say SGP is five times stronger and 100 times more rigid than PVB. It also often gets used in frameless structural glazing projects where water resistance is a top priority.
It is, however, a premier product. But if you need exceptional strength and weather resistance for your project, those extra pennies may be worth it.
About our laminated glass
At ToughGlaze, we stock top-quality, industrial-grade laminated glass that's ideal for domestic and commercial settings.
Like all our products, our laminated glass has the Kitemark seal of approval and meets BS EN standards. And because we do everything under one roof – from cutting to firing to treating – you can have this high-quality product customised in a huge number of ways.
Want those interlayers to be decorative? We offer
woven mesh patterns and
fabric interlayers. If you want your laminated glass to bear an image, text or other design, we can
digitally print any design for you.
And if you want added privacy, why not get
switchable security glass? This is a form of laminated glass that can be tinted from transparent to opaque at the touch of a button.
Whatever your laminated glass needs, we've got you covered.
Get in touch today for a quick, competitive quote.
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