Why Use a Polyurethane Sealant over Silicone Sealant?

Polyurethane Sealant VS Silicone Sealant - Difference Between Silicone and Polyurethene Sealant

A sealant is a versatile material, whether it's silicone sealant or polyurethane sealant.

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Either way it forms an integral part of most people's toolkit - DIY or Professional.

If you're interested in doing jobs around the house or you're part-way through a Professional renovation project such as bridge building or even Coach Building panels.

Whether you're planning to modernise a property or revamp the bathroom, here's one thing we know.

It's highly likely that in selecting the best sealant for the job, you're given it some serious thought.

Which is no easy job.

There are various forms of sealant or mastic sealant available, so which is the best option for you.

Here's why it is so important to spend time weighing up the options.

Hopefully, this guide will provide the regarding the difference between silicone and polyurethane sealant.

A brief introduction to mastic sealants

A sealant is a form of material, which is used to seal gaps and holes to make something airtight or watertight.

When you use sealant, you effectively form a seal, which prevents the movement of fluids and liquids.

Sealant is sometimes compared to caulking.

The main difference between building caulking and sealing is the flexibility of the seal. If you include mastic sealing in this equation sealants can not only seal but can also be used as an effective adhesive.

Sealants tend to be made from much more flexible materials.

This makes them useful for areas and joints where a degree of contraction or expansion may occur.

Polyurethene Sealant Properties

Mastic sealants such as polyurethane tends to be especially used in professional industries such as bridge building or automotive coach building. It's hard wearing approach and exceptional adhesive properties means it works well for professional applications where strength and speed are crucial.

Polyurethene sealant can also be used effectively in joinery because the sealant cures quickly and exceptionally hard into wood joints. These joints can then be sanded and painted over for a top quality finish.

They are not the same as adhesives, but it is possible to utilise sealants that have adhesive properties.

Sealants are used widely, and may come in handy for those working in the following industries:

• construction
• automotive
• engineering
• aerospace
• marine
• joinery
• road building
• bridge building

As well as those with an interest in DIY and property maintenance. There are many different forms of sealant both silicone and polyurethane sealants. This guide will focus on silicone and polyurethane sealant although these sealants have similarities, there are some significant chemical differences.

One of the principal differences between silicone and polyurethane sealants is the chemical composition. Silicone is an inorganic substance, while polyurethane is organic.

The primary difference between organic and inorganic substances is the presence of carbon. Organic compounds contain a carbon atom. In most cases, a hydrogen atom is also present. With an inorganic substance, it's uncommon for either atom to be present.

Polyurethane is a polymer, which comprises of a series of organic atoms connected by carbamate. Silicone is a unique material because it contains both inorganic and organic compounds.

These synthetic polymers comprise silicon and oxygen atoms, which are joined using C-Si bonds. The makeup of the chain exposes the organic elements of the structure to external influences.

This is why silicone makes such a versatile sealant for DIY as it can do most jobs satisfactorily - it's non organic composition makes it fairly dependable across the board and long lasting. Silicone is commonly used in construction and the development of paint and food products.

Chemical Breakdown

The chemical makeup of both silicone and polyurethane sealant are important. This is because the composition affects the breakdown of the materials. When organic and inorganic substances are exposed to UV light from the sun, the way they react differs.

Inorganic materials are less responsive to UV rays than organic chemicals. In the long-term, polyurethane, an organic material, will revert back to its natural state in response to UV exposure.This affects both the lifespan and versatility of polyurethane sealant. Polyurethane sealants set exceptionally fast and exceptionally hard as the organic compounds react faster with UV light.

This makes them especially useful for professionals working outside in industries such as road and bridge building. Polyurethane still has sealant and adhesive properties that exceed silicone and the fast acting nature helps project planning.

Paint and Sealants

(image courtesy of House Painting Tips with Silicone)

A key player in the discussion between silicone sealant and polyurethane sealant is paint...If you use paint (spraying, roller or brush) and need an adhesive or sealant in close proximity to your finished paint work. You will have come up against the common issue of silicone!

Silicone cannot be painted over its inorganic compounds will not allow paint to adhere or absorb into its top layer surface. The paint will simply peel off or in most cases simply run off during painting.

Polyurethane sealant is organic and after curing time it can be painted over and even sanded successfully to the same finish as other surfaces. This provides a huge advantage over silicone for both the DIY'er and professional alike.

Time Debate - Will my Mastic Gun be out sooner with Polyurethane?

It could be argued that silicone lasts longer (being non organic) than polyurethane (organic). Typically, a polyurethane sealant will produce effects that last between 5 and 10 years. While a silicone joint could last more than 20 years.

Most professionals however would argue that the quality and harder nature of Polyurethane sealants slightly edge out the longer lasting nature of Silicone. It's potentially why silicone is used more frequently in the home - where traffic and use is reduced. While polyurethane sealants are more prevalent in professional situations where drying time and hardening qualities are more crucial.

Which Polyurethane Sealant?

We always advise the Soudaflex 40FC range which is a high quality polyurethane sealant and adhesive perfect for a wide number of applications.

By far the biggest market for Soudaflex 40FC is the Coach Building Industry. It is perfect for bonding and sealing panels. It is also a high quality joint sealant, being used in road and bridge building, as well as industrial flooring applications.

Sold by the by the box (12) we have large stocks of all colours.

Colours White, Black and Grey Tube size is 310ml

Advantages & Benefits of Soudaflex 40FC Adhesive and Sealant:

• Very good adhesion on many materials
• Stays Elastic after curing
• Over Paintable**
• Very easy application
• Excellent resistance to many chemicals
• Developed for concrete applications
• Structural bonding in vibrating constructions

** Whilst Soudaflex 40FC is over paintable, a test area is recommended. Also 40FC is a flexible sealant and adhesive where the paint generally will not be. Cracks may appear in time as the sealant moves and the paint does not.

Buy Ultrimax supplies the full polyurethane sealant and mastic gun

310ml Black, Grey or White

Need More Help Selecting The Correct Silicone Or Polyurethane?

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Related Articles

There&#;s been a long spell of exciting growth trends for polyurethane. However, the peak in demand is still a long way off. What are future polyurethane uses?

Regular readers of our polyurethane guides and insights will know that we believe this versatile material is limitless in its ability to craft parts and components. Whatever the dimensions, performance requirements or tensile properties, and even if that polyurethane product is intricate and exacting.

We also believe that our faith in polyurethane&#;s ability to rise to any challenge will be fully tested in and beyond.

Why will interest in PU continue to grow? Mainly as it is increasingly recognised as the best material to precision engineer parts for a wide range of industrial applications. However, it&#;s also finding niches in homes, gardens and especially vehicles.

This is a dynamic topic, but here are just some future polyurethane uses in and beyond.

Greater emphasis on sustainability

The search for &#;greener&#; ways to produce machinery parts &#; and mass-produce everyday items &#; will no doubt gain momentum in the future.

There are important polyurethane attributes that make it a great solution for these specifiers who want sustainable product materials. That includes the incredible durability of polyurethane, reducing how often parts need to be replaced.

Is polyurethane recyclable? It most certainly is!

Also, it involves a low-energy manufacturing process. You can read more about this in our polyurethane manufacturing explained guide.

Also, natural, sustainable elements (water and carbon dioxide) are used to create flexible PU foam. Plus, polyurethane in all its forms is light in weight and offers valuable insulating advantages, adding to energy efficiency in construction for example.

The steps involved in creating, moulding and finishing polyurethane are governed by strict regulations and controls. Adding to the value of polyurethane as a safe, non-toxic material.

Also, it&#;s the ideal material for water jet cutting. The skilled engineers at Custom Moulded Polyurethane shape polyurethane (and other materials) using advanced water jet technology, as it is such an environmentally-sound method. It also produces a flawless finish.

Keep reading: 5 Products that could be made out of Polyurethane but currently are not

Lean manufacturing and cost control

This is another current industry trend likely to ramp up future polyurethane uses. Particularly in the automotive sector, where profit margins are ever-sharper, and pressure is on to find sustainable solutions.

However, polyurethane uses by industry are expanding all the time, from aerospace companies to firms who create car parks!

One of the main reasons for this industrial diversity is price. Despite its ability to match if not improve on the properties of rubber, polyurethane is highly advantageous when costing out prototypes. Or, to produce parts in large quantities.

The longevity of items engineered from polyurethane has cut down on machinery downtime, repairs and part replacement projects too. All of which contribute to improved productivity.

How many more industries will switch to polyurethane parts? Our guess is many!

Related article: Polyurethane for the Boat Industry

Lighter side of future polyurethane uses

As it&#;s so vital for industrial parts, it&#;s easy to forget that polyurethane applications can also be highly creative and innovative. Including feather-light foams in household furnishing furniture, and bedding.

Versions of polyurethane are used to manufacture clothing and footwear, a trend on a definite upward trajectory. Innovative future polyurethane uses are likely to also include new ways of optimising its abilities as a coating or adhesive agent.

As the properties and colours of polyurethane are infinitely changeable, it is likely to be used for many more everyday household items. Such dependable and safe toys and play equipment, durable kitchen and gym equipment and even decorative statement walls in homes.

Could there be whole buildings made from polyurethane one day soon? As it can be produced to be as hard as stone &#; and impervious to moisture, mould and extreme temperatures &#; that&#;s not as far-fetched as it sounds.

It is already the material of choice for many companies that make outdoor furniture, or artists who create pieces to display in open spaces.

Even the world of film and TV production is increasingly embracing the advantages of polyurethane, to create lightweight but realistic props and special effects.

Related article: Polyurethane can be used as an adhesive

5 Common Products that could be Better made of Polyurethane

Polyurethane is a really versatile material that can be used in many different products. We can be more inventive and find new ways to use polyurethane as it is strong, waterproof, resistant to mould and can be rigid or flexible. Let&#;s explore how it can be used for making running shoes, bags, a waterproof coat, bookcases and even for lining the bathroom walls.

1. Waterproof coat

We are all now more aware about recycling our clothes and buying clothes that will last that much longer. At the moment there are many fabrics that are made with a polyurethane finish that makes the fabric waterproof.

This can be seen in products such as nappies and shower curtains. So why not use this technology for making a waterproof coat that features many layers?

We know that polyurethane can be both flexible and soft or hard, so why not combine these two properties to make an entire coat that is tough, durable and keeps you dry? All aspects of the coat could be made from polyurethane, including the zip, poppers and lining.

2. Bookshelves and bookcases

It is a well-known fact within the manufacturing world that polyurethane is much more pliable and easier to work with than wood. So, if you are trying to buy less wood for your home then one wonderful alternative would be to buy products that are made of polyurethane, such as shelving and bookcases.

Polyurethane shelving and bookcases would be just as strong as a wooden shelf and just as attractive. It&#;s already used in commercial flooring, so why not shelving?

It can be personalised to your choice of colour and finish, plus another great benefit is that the polyurethane bookcase will not warp or grow mould when in a damp environment. It would also be possible to add decorative detail or create the shape of your choosing.

Related article: 5 Common Polyurethane Products You Didn&#;t Know About

3. The running shoe

As we mentioned when discussing the waterproof coat, there are many fabrics that contain polyurethane, so why not make a running shoe that is made only of polyurethane? This makes perfect sense as polyurethane simply ticks all the boxes that are needed in a functional and comfortable running shoe.

It is entirely possible to make a running shoe with a flexible and stretch to fit polyurethane upper that both hugs and supports the foot. This can also be coated in a waterproof covering, keeping you dry as you run or work out. The sole can be made from hard polyurethane that will create a hardwearing and durable sole. The shoe can be made in any colour and you&#;ll be able to throw it in the washing machine.

4. Lining for bathroom walls and wet rooms

Why not say goodbye to bathroom tiles? It makes absolute sense to use polyurethane sheets or blocks to line the walls of bathrooms or wet-rooms.

As we already know, polyurethane is more pliable than wood, and it is much easier to cut and handle than tiles and splash-backs. They will also be much lighter.

Polyurethane resin is used to lay floors, but we can easily take this idea and use it to protect the walls in our bathroom. Polyurethane sheets, tiles or blocks can easily be made and then applied to the wall. Not only are they easy to clean and waterproof, but they won&#;t attract the growth of mildew. It is the hygienic and long-lasting solution.

Also read: 5 most common uses of polyurethane

5. Shopping bags

Finally, another product that could be made from polyurethane is the humble shopping bag. We all need to stop using disposable plastic shopping bags that end up in landfill. The polyurethane shopping bag provides you with a great alternative as this bag would be built to last.

The bag could be made from polyurethane fibres that would make it lightweight and easy to roll up in your bag. It would also be incredibly strong and durable, especially if it was made with reinforced polyurethane handles, similar to the bands that are now being made for sports&#; watches. The bag would be easy to hold, waterproof and any colour you wish it to be.

What future uses of polyurethane can you think of?

The team at Custom Moulded Polyurethane could explore the theme of polyurethane products and exciting future applications for hours. As we understand its incredible potential, and the opportunities to manufacture polyurethane to match any specification.

The big question is, how are you going to &#;mould&#; the many benefits of polyurethane into your development plans?

If you are looking for more details, kindly visit Polyurethane Additives.