Have you ever wondered what keeps different glass sheets together?
The answer is interlayers. However, even among interlayers, there are options like PVB and SGP. Choosing among them is confusing for an ordinary consumer. That is what I will help you with today.
PVB vs SGP comparison below will help you understand what these are and which type of interlayer will serve you well.
What Are Glass Glazing Interlayers?
Many times, you need to bond together different layers of glass. To do so, a layer is placed in between them, known as the glazing interlayer. The job of this layer is to provide enough adhesion power to bond together two or more layers of glass.
Multiple such layers might be used with a glazing interlayer in certain aesthetic applications.
Glazing interlayer can be plastic or gel or some other material as well.
Now that you are aware of what a glass glazing interlayer is, it is time to look at two popular types of interlayers.
What Is PVB Interlayer?
PVB stands for Poly Vinyl Butyral. It is made from resin. Once you use this interlayer, you can block 99% of the UV rays. Consequently, the materials on which the light falls like a wood closet, the artwork will not suffer from fading due to UV rays.
Often, the interlayer is used for indoor glass applications rather than outdoors. If it is used in outdoor applications, efforts are made to ensure that the edges are not exposed as that will increase wear and tear.
Advantages of PVB Glass
1. Easy Availability
The reason why this PVB interlayer has become so famous is because of its easy availability. For starters, it is manufactured by multiple companies all over the world. Hence, availability isn’t an issue.
Another advantage is the low cost. Due to competition and economy of scale, the cost of PVB glass interlayer is pretty affordable.
2. Numerous Color and Finish Variants
Of course, since you’re speaking about glass interlayer, it is essential to look at the variants available. Fortunately, this one is available in different color and finish variants. It means that you can get an interlayer that perfectly suits the application you’re looking for.
Disadvantages of PVB Glass
1. Lack of Support When Glass Breaks
PVB layer is present between both the glass sheets. When both the layers break or suffer from any impact and disintegrate, the PVB layer between them will not remain rigid. It is susceptible to flopping in one direction whenever the sheets of glass disintegrate.
While it is very unlikely that both the sheets of glass break, it does happen. That is because glass sheets inside the structure are less susceptible to such damage. Consequently, the applications of PVB are limited to interior use.
What Is SGP Glass Interlayer?
SGP stands for SentryGlas Plus. The interlayer is made from ionoplast. It is a primarily tough plastic that bonds the different layers of glass and increases the structural integrity of the entire assembly.
An advantage of SGP is that it does not let the glass disintegrate completely and shatter to pieces in case of an impact. It will attempt to hold the pane together, certainly an advantage. Due to the same, you will find that SGP is often used in structural glazing. This is where the weight of the entire structure or a part of it might be on the glass panes.
Advantages of SGP Glass
1. Excellent Structural Integrity
Needless to say, SGP has much higher structural integrity. If both the glass panes disintegrate, SGP will remain rigid. It will not bend to one side.
This certainly reduces the risk of using SGP in external structures. It also opens up SGP applications and structures with high weight on the glass. Of course, it is done through proper structural audit and architectural principles, but still, SGP can support such applications.
This is why you will find SGP laminated glass in the exterior facades of many modern buildings.
2. Numerous Finish and Color Variants
When it comes to any glass applications, the lack of finish or color options is a disadvantage.
When you try to buy SGP glass, you will realize that numerous color and finish options are available. That can make things easier when planning any structure or any interior using this type of glass.
Disadvantages of SGP Glass
1. Limited Manufacturers
Truth be told, SGP interlayer is available only from a single manufacturer. At the same time, you might think that it won’t affect your application, but that’s not true.
Lack of competition means it is much more expensive than the PVB interlayer. Not only that, you might experience shortages when working on a large project. That can delay your project. While this seldom happens, it is always possible to deal only with a single manufacturer worldwide.
SGP vs PVB: What Is the Difference Between Them?
With the basics of both types of interlayer clear, now is the time to look at their differences.
PVB is in plasticized form that keeps two glass layers together. It has been used as an interlayer for a long time. Constituents of the PVB include alcohol and aldehyde. Polymers of butyraldehyde are used to manufacture poly vinyl acetate; the relative compound formed is easy to use and robust.
SGP is made by DuPont. The company acquired a worldwide license to manufacture and distribute this interlayer. That is why; the exact composition of SGP is a pretty well-guarded secret. However, generally speaking, a plastic composite interlayer bonds the two glass sheets at high temperatures.
2. Structural Integrity
Honestly, the structural integrity of PVB is not that bad. It only feels when both the sheets of glass disintegrate. If you have worked in the construction industry or the glass manufacturing industry, you will realize that that is a very rare occurrence.
However, it does occur in the case of natural calamity or when the property is damaged fully. In that case, the laminated glass panel will not stay still and can fall. This undermines the strength of the PVB interlayer.
If you compare PVB with SGP head-on, SGP is five times stronger than PVB. Similarly, when you compare the hardness of both, SGP laminated glass is 100 times stronger. It does not suffer from structural integrity issues even when the glass panes break. In that case, it can also hold them together in an upright position.
In a nutshell, SGP glass is a definite winner for structural integrity.
Simply put, SGP glass is clearer than PVB one. Merely looking at the condition of glass when it’s new is not a good idea. You have to also find out whether it changes its color or develops a tint after a few years or not.
The good news is that in this regard as well, SGP has an advantage. It is colorless at the start, but it does not turn yellow even after significant exposure to the rain or sun. The yellowing coefficient is merely 1.5 or even lower in some cases.
Now, the question is, what is the yellowing coefficient of PVB glass? Usually, it is between 6 to 10, depending on the manufacturer and the quality of PVB glass.
If you need a glass that does not turn yellow and is clear right from the start, the SGP glass certainly meets that requirement.
4. Moisture Resistance
You might have noticed that I highlighted above, PVB interlayer is used only in closed edge applications. Usually, any type of glass sheet is more susceptible at its edges. That is why a real testament to the usability and structural integrity of the glass is what it can handle at the edges.
The problem is when the edges are open and the PVB interlayer is exposed to rain, it will start absorbing moisture. It will suffer from decay when it absorbs moisture.
In that case, it might not be able to hold the glass sheets together after a few years. While this is still a slow process, it is susceptible to moisture and rain. This is why metal caps are often used when balustrades are made from PVB glass.
On the other hand, SGP does not suffer from such problems. It does not have a high moisture absorption rate. Even if open edges are used, the wear and tear of the SPG interlayer are much less.
If you’re looking mainly for glass to be used in humid areas, SGP glass is undoubtedly a winner in that case.
PVB is available in different thickness options like 0.38 MM, 0.76 MM, 1.14 MM, etc. Usually, it is available in multiples of 0.38 MM. The exact thickness you opt for will depend on the type of application you are dealing with.
Not only that, many companies and various properties use the PVB interlayer with a sound blocking layer, an extra stiff layer, and so on. When choosing the PVB interlayer, you have to consider the properties you need and take a call after that.
The exact variant of glass you need will also determine the thickness of the SGP layer. The thickness of SGP layer is usually 0.89 MM, 1.52 MM, 2.28 MM. It depends on the application you are dealing with. For example, color laminated glass with SGP interlayer will have a different thickness than ultra-clear laminated glass, and so on.
In terms of thickness, there is nothing to choose from apart from the fact that the thinnest PVB variant available is approximately half that of the SGP interlayer.
6. Edge Strength
As highlighted above, edge strength is the weakest link of any glass type or interlayer. The same is true for PVB as well as SGP interlayer.
In the past twenty years, there has been extensive testing done on SGP interlayer and SGP glass specimens. Up until now, it has been found that there are hardly any delamination or defects in the edge of the SGP glass interlayer.
On the other hand, the PVB interlayer is set to keep its structural integrity for ten years. The same is the lifetime of the PVB glass.
In a nutshell, when you look at the edges, stability of both interlayers, SGP has an advantage.
Seldom will you use PVB or SGP laminated glass on a stand-alone basis. Of course, you would have to use it with some other material. That is why, whether you go with PVB or SGP, you have to look at the materials with which the same is compatible. Only once you consider that you can choose the right interlayer and right laminated glass.
PVB laminated glass does not have compatibility with many materials. The list is really short.
When dealing with the SGP laminated glass, it can work with metal, mesh, wire, and fabric. That is why, when you want to use such laminated glass, SGP won’t provide you with many compatibility issues. It matters a lot in real-world applications.
You might think, up until now I’m going into only the technicalities of both the interlayers. Ultimately, what determines the usage of PVB laminated glass or SGP laminated glass are the applications they offer.
While understanding the technicalities is essential but so are the applications. That is why I will now compare both of them on applications to have a clear view of what they can be used for.
PVB is used in car windshields as well as solar back sheets. This is the primary application of this type of glass. The reason for the same is that the edges are close to the windshields and the solar back sheets.
When you look at the primary application of SGP laminated glass, they are used for balustrades and canopies. Apart from that, SGP keeps the sheets of glass together even if they break. Since SGP can handle outdoor weather pretty well, it is used in exterior applications more.
When it comes to applications, none is a clear winner. It all depends on your requirement.
9. Wear and Tear
It is essential to look at the wear and tear that each interlayer suffers from. When opting for any laminated glass, of course, it will be in use for years together.
Even after 5 to 7 years of consistent use and exposure to weather elements, the SGP layer does not show any age defects. It is a clear indication that it can handle any weather and keep the glass sheets together.
On the other hand, while PVB laminated glass does not break down entirely, signs of wear and tear might be visible.
The good news is, even after 5 to 7 years of use, both the glass will not suffer from any haze or color change. That way, both of them are on equal footing.
However, the fact that SGP laminated glass does not suffer from age defects makes it a good choice.
10. Load Carrying Capacity
A lot of variables are involved when comparing the load-carrying capacity of PVB and SGP laminated glass. You are to consider the thickness and the kind of load applied to the glass sheet.
However, if you compare them head to head in similar conditions, SGP laminated glass can handle a higher weight. The load which will deform PVB glass won’t deform SGP glass of the same thickness.
If you’re looking for a glass type that can handle the load, SGP is a clear winner.
Frequently Asked Questions
1. Can PVB and SGP laminated glass block UV rays?
Yes, PVB, as well as SGP laminated glass, can certainly block UV rays. They can block 99% of the UV rays. That is why, when it comes to UV resistance, there is nothing much to choose between them.
2. Can PVB and SGP laminated glass be used in aesthetic applications?
Yes, both PVB and SGP laminated glass can be used in aesthetic applications. They are available in different finishes and color options. Due to the same, it becomes easy to make various types of glass sheets for multiple applications.
3. Is PVB conductive?
The thermal conductivity of PVB is pretty limited. That is why; you certainly cannot consider it as conductive.
4. Is PVB soluble in ethanol?
Yes, it is soluble in ethanol. In fact, it is soluble in most mixed solvent systems. However, since PVB laminated glass has closed edges, such solvents cannot reach the interlayer, so dissolving PVB is not easy.
5. Is PVB biodegradable?
PVB is nondegradable. It has good elasticity and high compatibility with other polymers.
Hope you won’t be confusing yourself with all the jargon surrounding SGP vs PVB, as you read through this post.
Now, the next time around, you have to choose between these two types of laminated glass; refer to my guide above, and you will be able to select between them easily. Not only that, you can easily understand which one can serve you longer and is suitable for the application you’re looking for.