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Silicone sealant alternatives: What other types of sealants can you use?

Thomas Besley | 4 min. read

Silicone sealant alternatives: What other types of sealants can you use?

Silicone isn’t the only type of sealant you can use. There are so many different types of sealant, but most companies seem to think that silicone is the only sealant out there. If this sounds like you, don’t worry. 

Here at Forgeway, we manufacture over 3000 tonnes of adhesives and sealants annually. We don’t manufacture silicone sealants though. Companies often come to us when they want a silicone sealant alternative.

In our opinion, the best silicone sealant alternative is to use an MS polymer sealant. However, we know a few other options too that may suit your application better.

With our years of industry experience, we know the alternative sealant options, and we want to educate you. This article will detail the other sealant options and will help you establish what makes a good sealant product. By the end of the article, you will have a good idea about which sealant product you want to explore further.

When should you consider an alternative to silicone sealants?

You may have come to this article looking for an alternative sealant for several reasons. However, there are a few common reasons why companies look for a silicone sealant alternative.

Silicone sealant alternatives are easier to workYou can find a sealant that is easier to work with

Or there may be a completely different reason why you are looking for a silicone sealant alternative. Ultimately you want a sealant that suits your needs.

What qualities should you look for in a sealant?

When it comes to choosing a suitable sealant, you will have a few characteristics in mind that are important to you. But what other qualities should a sealant have?
There are some characteristics that a sealant must have. There are also some characteristics that a good sealant should have. So we split this section into two parts.

What a good sealant must have

  • Good colour stability – Typically, you will use a sealant where people can see it. Yellowing of sealants is a massive problem in the sealant industry. A sealant with poor colour stability will damage the aesthetics of the structure you are sealing. ASTM G154 testing is one of the main ways to see if the sealant will maintain its colour when exposed to weathering conditions.

Yellow sealant like siliconeSealant yellowing can be a big problem
  • Easy to finish – As most sealants are for aesthetic purposes, you will need to ensure it actually looks good. Getting a good finish with a sealant takes skill. However, this characteristic is often very subjective. We might consider a sealant to be ‘easy to finish,’ but you may struggle to achieve a good finish. It all comes down to what you find to be easy. You will want to make sure of this before purchasing the sealant.
  • Non-shrink capabilities – Most of the ‘must-have’ characteristics of a sealant relate to its aesthetics. Nonetheless, from a performance point of view, a sealant mustn’t shrink. If it does shrink, it will obviously not do its intended job; to seal.

What a good sealant should have

  • Good workability – A sealant that is easy to work with is more than just about getting a good finish. As we outlined in the point above, getting a good finish is a ‘must-have’. However, it makes the application process a lot better if the sealant is easy to work with. ‘Easy’ is of course subjective. But we would say that if you have been using silicone and find it easy to use, you will want a sealant with similar viscosity. 

It is important to get a good finish with a silicone sealant alternativeA good sealant will be easy to work with and get a good finish

The silicone sealant alternatives

Hybrid polymer (AKA MS polymer) sealants 

MS polymer sealants are the most common hybrid polymer sealants. They tend to have greater tensile strength than silicones. You also don’t need to worry about struggling to overpaint MS polymer sealants

But where MS polymers tend to stand out is their strength and weathering performance. They can achieve high strengths that silicones cannot reach. They also don’t need a primer to reach those high strengths like polyurethane sealants.

MS polymer sealants combine the weathering performance of silicones with the strong performance of polyurethanes.

MS polymers are an effective silicone sealant alternative

However, they tend to be more difficult to work with than silicones as they are usually thick. This means they are often more difficult to gun out. However, most people can overcome this issue by using an applicator that is better suited for viscous sealants.

Polyurethane sealants 

Polyurethane sealants are often the go-to sealants for applications where you need a sealant with good strength. They can achieve similar strengths to MS polymer sealants. 

A high-quality polyurethane sealant (much like MS polymer sealants) will not cause the staining that silicones tend to cause. They also can achieve very clear and transparent finishes like silicones. MS polymers struggle to achieve this clear finish.

Nonetheless, companies tend to stay away from polyurethanes for health reasons. This is because they contain isocyanates. Isocyanates are highly irritant. They can cause health problems to the operators who use polyurethane sealants. 

Isocyanates have also faced fresh scrutiny from REACH. You will need to comply with restrictions before you can use polyurethane sealants.

Health risks can be associated with structural adhesivesHealth risks associated with Polyurethane sealants

The other reason companies stay away from polyurethanes is the weathering resistance. Polyurethanes cannot achieve the same levels of weathering resistance as silicones or MS polymers.

The best silicone sealant alternative for you

Now that you have learned about the silicone sealant alternatives, you will want to decide which sealant you can use instead of silicone. You may have determined that silicone is still the best sealant for your application. 

But you read this article because you have been experiencing a problem with your silicone sealant. Whatever the problem is, you need to solve it.

Here at Forgeway, we manufacture a range of sealants for different applications. However, we don’t manufacture silicone sealants. Customers often ask us “what is the best silicone sealant alternative.” We would always say that MS polymer sealants are the best alternative to silicones.

MS polymers and polyurethanes are the two best silicone sealant alternatives. They are very similar to silicone and in most cases, they have higher performance than silicone sealants.

MS polymers are likely the best option for you if you are looking for a sealant that has:

  • Good UV resistance
  • High strength characteristics
  • And you can paint over it

However, if you want that same strength but need the sealant to have a clear finish, you will want to look into exploring polyurethane sealants.

You should have a good idea about which sealant is best for your application. Nonetheless, we know it is still difficult to know which sealant is best for you. 

We are here to help if you still can’t decide for yourself. Click on the banner below if you would like some help choosing a silicone sealant alternative.

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Thomas Besley

Thomas is the Content Manager here at Forgeway. Thomas' job is to translate the technical jargon from the ivory tower of academia into easy-to-read content that everyone can understand. Forgeway's mission is to answer every question our customers and prospective clients ask, or are apprehensive to ask.