Skip to main content

«  View All Posts

Silicones vs. MS Polymer Sealants; A guide to choosing the best sealant for your application

Thomas Besley | 4 min. read

Silicones vs. MS Polymer Sealants

When it comes to choosing a sealant, most people automatically think of silicone. In fact, most of the time, people use the word ‘silicone’ when they mean ‘sealant’. In reality, there is a range of different sealant options. People often compare MS polymer sealants and silicone sealants.

Here at Forgeway, we manufacture a range of industrial adhesives and MS polymer sealants. While we don’t manufacture silicone sealants, we have had plenty of experience with them over the years. We want to help you choose whether silicones or MS polymer sealants would be the best choice for your application.

This article will go through the advantages and disadvantages of both chemistry types to help you choose which one could be a good fit for your needs. By the end of the article, you will have a greater understanding of both sealant types and become an educated buyer.

What are silicone sealants?

Silicones are synthetic polymers made of a combination of silicon, oxygen, carbon, and hydrogen. 

They are the most common type of sealant and are highly popular in construction applications as they are readily available in most builders’ merchants. 

Like ‘Coke’ becoming the household name for most cola-flavoured soda drinks, silicone has become the household name for most sealants.

If someone says ‘I need a silicone’, they most likely mean they need a sealant. 

They are often referred to as the ‘cheap and cheerful’ sealant, as they usually don’t cost much and will do the job.

Silicone sealants are very popular

What are MS polymer sealants?

MS polymer sealants are a type of sealant made from a hybrid of silane-modified polymer and polyether. 

They are often referred to as hybrid polymer sealants and were formulated to combine the characteristics of silicone and other sealant types, such as polyurethanes. 

They are typically considered the premium sealant option compared to the ‘cheap and cheerful’ silicones, but you can also find inexpensive MS polymer sealants.

MS polymer sealants are usually considered premium

What are the pros and cons of silicone sealants?

Silicones offer several advantages and disadvantages, such as their high-temperature resistance, ease of use, and lower price. In this section, we will go over these pros and cons in more detail.

A typical silicone sealant will have a temperature resistance of up to 250℃, which is a major advantage over MS polymer sealants. 

The increased temperature resistance of silicones means you can use them in applications that could experience increased temperatures without affecting performance. 

Silicone sealants are also usually low viscosity, which means they can be easily applied using a caulking gun without any special tools or techniques. 

The low viscosity of silicone sealants also makes it often easier to get a good finish for inexperienced sealant users. However, skilled operatives will not find MS polymer sealants any more difficult to work with.

Another advantage of silicone sealants is their lower cost compared to other types of sealants. They are widely available and are often less expensive than other sealants.

silicone sealants often require less skill to get a good finish

Disadvantages of using Silicone sealants

Whilst silicones are often the cheaper sealant solution, they are often cheaper for a reason. A lower price means lower quality.

Cheap silicone sealants (around £3 a tube) will often have poor mould resistance. If you intend to use the sealant in a humid environment, cheap silicone will likely start to mould after 6 months.

Another disadvantage to using silicones is their lack of overpaintability. Due to the hydrophobic nature of silicones, you will not be able to paint over them.

Perhaps the biggest disadvantage of silicones is their poor adhesive performance. If you intend to use the sealant for semi-structural bonding, a silicone sealant is likely to perform poorly.

The silicone sealants that are readily available at low cost will not have enough strength or ‘grab’ to be used for bonding purposes.

MS polymer adhesives can be a good choice as a metal bonding glue
You cannot use most silicones for bonding purposes

What are the pros and cons of MS polymer sealants?

MS polymer sealants also have a few advantages and disadvantages. This section will go over these in more detail.

Advantages of MS polymer sealants

The main advantages of MS polymer sealants are their strong adhesion and flexibility characteristics. MS polymer sealants can adhere to a wide range of materials, including metals, plastics, and even glass.

Their flexibility makes them a good choice for applications where movement or vibration is expected, such as joints and seams. They can also be used in structural bonding applications, such as bonding panels, as they have a higher strength than silicone sealants.

MS polymer sealants are also overpaintable. This means that you can paint over them after application, unlike silicone sealants. This makes them ideal for use in areas where you need to achieve a specific color or finish.


Disadvantages of MS polymer sealants

One of the main disadvantages of MS polymer sealants is their higher cost compared to silicone sealants. They are generally considered to be a premium sealant due to their superior properties.

Another disadvantage of MS polymer sealants is their longer curing time. While they do form a skin faster than silicone sealants, they can take longer to reach full cure. This means that you may need to wait longer before putting the sealant into use.

MS polymer sealants also have lower temperature resistance than silicone sealants. While they can still withstand moderate temperatures, they are not suitable for use in applications that will experience extreme heat above 150℃.

Questions to ask when choosing a sealant

When choosing a sealant for your application, there are several factors to consider. Here are some questions you should ask yourself:

  • What materials are you bonding or sealing together?
  • Will the application experience movement or vibration?
  • What is the expected temperature range of the application?
  • Is the sealant going to be exposed to UV rays or extreme weather conditions?
  • Do you need the sealant to have structural properties or just act as a sealant?

Answering these questions will help you determine whether silicone or MS polymer sealants are the best choice for your application.

ms polymer sealants can withstand weathering exposure

Silicone or MS polymer; Which is the best sealant for your application?

Now that you know more detail about each option, it’s time to make a decision. However, it’s not always easy to know what to choose.

Here at Forgeway, we manufacture a range of industrial adhesives and sealants including MS polymers.

Whilst we would always recommend MS polymer sealants, there are often occasions where we would tell a customer to use silicones instead.

If you want a cheap and cheerful sealant or you want a sealant with high temperature resistance, a silicone would be best for you.

If you would prefer to spend more on a higher quality sealant that has better mould resistance and greater adhesive properties, an MS polymer would be best for you.

If you’re still unsure about which sealant to explore further, you can get in touch with an expert to help you find the best sealant for your application.

Or, if you want to do a bit more research yourself, our article on MS polymers will give you more detail about these sealants. Click here to read more.

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.