MATERIAL SELECTION GUIDE
Choose the right materials for your profiles
MATERIALS USED IN PROFILE MANUFACTURING
Seal profile materials are designed and selected according to their intended use and operating conditions. V.A.V. Group makes its own raw material mix for seal profiles, which allows us to have complete control over the various properties of the profile, whether it is hardness, color, or other special features.
The primary materials used for profiles are silicone rubber, TPV (thermoplastic vulcanizate), and TPE (thermoplastic elastomer). These materials all have their functional properties, with some overlap in potential use cases. Silicone rubber has the broadest operating temperature range, and TPE and TPV profiles have excellent chemical resistance, which makes both well-suited for multi-component seals. Fire X is our self-extinguishing silicone profile that fits European standards for rolling stock, the maritime industry, and other sectors. It can also be used for doors and windows in other transport industries.
THE SHORE HARDNESS SCALE
WHAT IS THE RIGHT SHORE SCALE FOR YOU?
The Shore hardness scale provides a standardized way to compare the hardness of different materials, ensuring that the selected material meets the specific needs of the application.
The Shore hardness scale is a system used to measure the hardness of elastomers and polymers. The scale is named after its inventor, Albert Shore, and quantifies a material’s resistance to indentation, providing a numerical value that helps in determining its relative hardness or softness. There are several Shore hardness scales, with Shore A and Shore D being the most commonly used for rubbery and harder materials, respectively:
Shore A Scale
This is typically used for softer, more flexible materials like rubber, soft plastics, and elastomers. The scale ranges from 0 to 100, where lower values indicate softer materials (a rubber band might have a Shore A hardness of 20), and higher values indicate harder materials (a shoe heel might have a Shore A hardness of 70).
Shore D Scale
This scale is used for harder plastics and polymers. The scale ranges once again from 0 to 100, the higher the number, the harder the material. For example, a hard plastic like a helmet might have a Shore D hardness of 80.
How Does the Shore Scale Work
The hardness is measured using a device called a durometer. The durometer has a specific indenter shape that is pressed into the material with a consistent force. The indentation is measured, and the hardness value is displayed on the Shore scale. The less the indenter penetrates the material, the higher the Shore hardness number, indicating a harder material.
How do you select the right material for your specific application? For instance, softer materials (lower Shore A values) might be preferred for better flexibility and sealing capabilities, while harder materials (higher Shore A or Shore D values) may be needed for durability and resistance to deformation. A Shore A material of about 5 to 10 is very soft and flexible and can be used in wearable medical devices or cushions or soft and chewable child or pet toys. On the opposite end, a Shore D 100 material is incredibly hard and rigid, and is used high-performance gears and bearings that deal with prolonged mechanical stress and friction.
Manufacturers will commonly have a planned maintenance day, where all machinery with such seals is shut down and opened up, and all profiles are removed and replaced with new ones. The Shore scale of the material must be accurate so that maintenance is scheduled appropriately and worn-down profiles don’t pose a risk to the machinery and production line.
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Silicone rubber
What is silicone rubber?
Silicone rubber is a versatile, synthetic elastomer made from a polymer composed of silicon, oxygen, carbon, and hydrogen. It is widely used in various industries, including automotive, medical, and consumer goods, due to its stability over a wide temperature range and resistance to environmental factors. Its applications range from seals and gaskets to medical devices and kitchenware.
Silicone rubber is an excellent material for demanding conditions. We can adapt its properties to fit various operating environments; the properties of silicone rubber include resistance to steam, pressure, moisture, chemicals and oils, UV, and ozone. Silicone rubber has a superior operating temperature range, making it a perfect choice for almost any industry.
Properties of silicone rubber
Operating temperature of -80 °C – +250 °C
Extruded hardness Shore A 10-80
Tensile strength 200-1500 PSI
Basic, metallic, and RAL chart -colors
Silicone rubber is commonly used for insulation in many industries and is an excellent electrical insulator. We also manufacture non-stretch silicone profiles, foam silicone, and self-adhesive seals, all of which have their own special advantages. Silicone rubber has an incredible range of applications.
Applications for silicone rubber
Window and door seals
Silicone tubing (including food-grade silicone)
Rings and gaskets
Pressure profiles
HVAC tubing
Appliance seals
FOAM SILICONE
What makes foam silicone different from our other profiles is its “spongy” closed cell silicone structure, which works almost like a foam mattress; it’s thick and sturdy and holds its shape well, making it especially great for example, insulating corners, where it provides support and keeps out the cold air and outside noise. Our foam silicone comes quite often as a co-extruded structure with two different grades of hardness: the soft, flexible, round, and insulating part and the harder “spine” that settles into the groove and makes installation easy while keeping the seal from stretching. We can also provide threaded foam silicone, which absolutely prevents the silicone from stretching.
The spongy structure of foam silicone makes it an excellent noise insulator, perfect for loud urban environments.
The properties of foam silicone aren’t too different from our other profiles, but there are some areas where it excels. Noise penetrates better than air and will slip through even the smallest of cracks, but foam silicone has exceptional noise-canceling properties. For example, proofing your front door or balcony doors with foam silicone can notably muffle outside noise, something that people living in big city apartments are all too familiar with. We recommend installing the foam silicone on the warmer doorcase side instead of the leaf for best results.
Foam silicone is still criminally unrecognized, even when it has the potential to be a real game-changer for insulation, as well as for noise-canceling in big cities and homes near highways.
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FLUOROSILICONE
Silicone and fluorosilicone are elastomers made from oxygen, carbon, and hydrogen but differ in their polymer chains and properties. Silicone has a silicone polymer chain, while fluorosilicone includes fluorine atoms, changing some of its chemical and physical properties.
In summary, silicone is flexible and elongates well, while fluorosilicone is more heat and chemical-resistant, stronger, and more durable. The right material should be chosen based on these properties.
Silicone | Fluorosilicone | ||
Heat resistance | Breaks down above 149°C | Withstands up to 204°C | |
Chemical resistance | Lower chemical resistance | Higher chemical resistance | |
Mechanical properties | Excellent flexibility and elongation | Lower flexibility and elongation but higher tensile strength and tear resistance | |
Durability | Longer lifespan, more stable, and less prone to swelling and shrinking compared to silicone | ||
Hardness | Shore A 10-80 | Shore A 40-80 | |
FDA Compatibility | Generally food-safe | Typically not FDA-approved for food contact | |
Applications | Used in seals, gaskets, hoses, and medical devices due to its flexibility | Used in aerospace, automotive, and oil and gas industries for its heat and chemical resistance; also used in O-rings, seals, and gaskets |
PLATINUM SILICONE
Platinum silicone or platinum-cured silicone uses, as you could guess from the name, a platinum-based catalyst to cure. The process results in a material that is free from any by-products like peroxides, which makes it safe for medical- or food-grade products. Platinum silicone has high thermal temperature, chemical resistance, and elasticity.
Due to its high purity and non-toxicity, platinum silicone can be used in medical devices, kitchenware, and baby products. It is also clearer than other silicone types and maintains this clarity without yellowing over time.
CHLORINE-FREE SILICONE
Chlorine – or halogen-free silicone profiles are produced by adding organic, chlorine-free peroxides to the silicone during its vulcanization instead of the traditional peroxide that has been used for decades in the silicone vulcanization process. Chlorine-free silicone can be used in all profile applications, from door and window gaskets to ventilation systems and many more.
The benefits of chlorine-free properties are important, for example, in shipbuilding and rolling stock sectors, where silicone profiles work as a fire-safe insulator. One of the advantages of chlorine-free silicone is that should it be exposed to flames and burn; it will not produce harmful chlorine compounds or hydrochloric acid.
FIRE X SILICONE
Fire X profiles are made of self-extinguishing silicone that withstand temperatures up to 300°C. Not only does the Fire X withstand extremely high temperatures for long periods of time, but it is also fire-retardant and non-flammable in itself.
In comparison to intumescent seals and profiles that expand when exposed to high temperatures, Fire X profiles are airtight in all temperatures. This prevents the spread of smoke, carbon monoxide, and other dangerous gases to other rooms or compartments before the temperature rises to a certain level. Since carbon monoxide can reach dangerous levels without an actual fire, Fire X seals are significantly safer than seals and profiles that only prevent the spreading of fires. Furthermore, if the compartments are sealed air-tight with Fire X profiles, they will significantly slow the spread of fire or even suffocate the flames in certain conditions.
In normal conditions, the Fire X profiles act as normal silicone profiles, unlike intumescent seals that have little to no sealing capability without high temperatures.
Fire X is a silicone profile enhanced with fire-retardant and halogen-free materials. In short, the seals and profiles (along with other materials used in trains and their interiors) cannot ignite easily, burn aggressively at any point, or emit toxic fumes when predisposed to extreme heat. Fire X profiles are treated so that they will not burn but rather smolder and char even at the highest temperatures, maintaining their ability to prevent fires from spreading. This is a crucial feature for any profiles used in doors, windows, and latches on rolling stock.
Halogen-free profiles enhance the safety of railway passengers as well as firefighters sent to the scene, as they will not be exposed to toxic gases. Halogen gases are also highly corrosive, which may cause further damage to other components of the vehicle (or building).
Properties for FireX
Self-extinguishing
Hardness Shore A 10-80
Operating temperature of up to 300°C
Basic and limited RAL colors
FireX certificates
IMO FTPC Part 2 & 5
UL 94 V Classification V0
EN 45545-2
Fire X and TPV can replace the commonly used EPDM, which can also be treated to withstand extreme temperatures. The advantages of Fire X, compared to EPDM, are a greater variety of hardnesses and colors, along with more manageable and often more reliable joints in angles or round shapes.
WHAT IS THE EN 45545 STANDARD?
EN 45545-2:2020 is a European standard specifying fire behavior requirements and testing methods for materials, components, and systems used in railway vehicles. This standard is part of a series of European standards (EN 45545) that were developed to improve the safety of railway vehicles concerning fire hazards. It is specifically concerned with the fire safety of railway rolling stock.
EN 45545-2:2020 covers the fire behavior and fire resistance of materials and products used in railway vehicles. It provides requirements and testing procedures for assessing the reaction to fire of these materials, components, and systems. The standard applies to various materials used in the construction of railway vehicles, including seat covers, flooring materials, insulation, cables, and other interior and exterior elements.
All new railway projects should follow the updated 2020 version of the EN 45545 standard and meet all its requirements in all components.
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Main properties of different silicone compounds
Conventional silicone rubber
Silicone rubber is a very versatile synthetic elastomer. It is widely used in various industries, including automotive, medical, and consumer goods, due to its stability over a wide temperature range and resistance to environmental factors. Its applications range from seals and gaskets to medical devices and kitchenware.
- Heat resistance: Breaks down above 149°C
- Excellent flexibility and elongation
- Generally food-safe
Foam silicone
- Foam silicone has a its “spongy” closed cell silicone structure
- Great for insulating corners, windows and doors, where it provides support and keeps out the cold air and outside noise.
- Foam silicone is often co-extruded with harder surface protecting the softer inner material as well as often acting as a spine for installation purposes.
Fluorosilicone
- Heat resistance: Withstands up to 204°C
- Higher chemical resistance
- Lower flexibility and elongation but higher tensile strength and tear resistance. Longer lifespan, more stable, and less prone to swelling and shrinking compared to silicone
Platinum Silicone
- Heat resistance: Withstands up to 230°C
- Safe for medical- or food-grade products.
- High chemical resistance, and elasticity.
- Usually clearer than other silicone types and maintains this clarity without yellowing over time.
Chlorine-Free Silicone
- Chlorine-Free Silicone will not produce harmful chlorine compounds or hydrochloric acid when exposed to extreme temperatures (fire).
Fire X Silicone
- Self-extinguishing, non-flammable
- Operating temperature of up to 300°C
- IMO FTPC Part 2 & 5
- UL 94 V Classification V0
- EN 45545-2
Thermoplastic elastomer - TPE
What is TPE?
TPE is a class of materials that combines the properties of thermoplastics (like polyethylene and polypropylene) with elastomers (like rubber). TPEs are typically composed of a mixture of hard and soft segments, with the soft segments providing elasticity and the hard segments providing structural integrity.
TPE seals and profiles offer flexibility, resilience, and excellent sealing capabilities. They are softer and more elastic than PVC, making them suitable for applications requiring a tight seal and flexibility. The latest material developments have brought more rigid TPE materials to the market, thus closing the gap in this sector.
While a material like PVC typically has a higher melting point and is more suitable for high-temperature applications, TPE excels in low-temperature flexibility, ensuring effective sealing even in cold climates. TPE can also be treated to withstand very high temperatures, up to the point of being fireproof.
Properties of TPE
Excellent flexibility and elasticity
Wide range of hardness options, from very soft to rigid
Wide range of color options
Moderate to excellent resistance to UV radiation and weathering, depending on the specific formulation
Good chemical resistance can vary based on the TPE type
Extremely versatile when it comes to thickness, shape, and size
Hardness 40 Shore A – 45 Shore D
Operating temperature of -40 – +120°C
TPE’s flexibility and elasticity make it ideal for applications where a secure and pliable seal is necessary. TPE seals are used in industries like automotive, where they are employed in weather-stripping and fenestration applications, providing an effective seal for doors and windows. The softness of TPE makes it suitable for areas where impact resistance and noise reduction are essential.
Applications for TPE
Soft-touch grips and handles
Overmolded parts and handles on tools and consumer products
Automotive interior components, e.g. dashboard trim and cup holders
Appliance seals
Medical devices and equipment
Cable and wire insulation
TPE materials are also known for their recyclability and environmental friendliness. TPE is often considered a more environmentally friendly option than materials like PVC and EPDM, as it can be reprocessed. While a material like PVC is generally more cost-effective than TPE, TPE’s superior performance and environmental considerations may justify its higher initial cost in specific applications. Thanks to its recyclability, TPE can become more cost-effective than PVC when considering disposal costs.
Due to its recyclability, TPE can be more cost-effective than other alternatives, like PVC.
Thermoplastic vulcanizates (TPV) are part of the thermoplastic elastomer (TPE) family of polymers but are closest in elastomeric properties to EPDM thermoset rubber, combining the characteristics of vulcanized rubber with the processing properties of thermoplastics. Like TPE, TPV is recyclable and has good UV, ozone, and chemical resistance, and in some cases, even greater resistance than EPDM.
What is the difference between TPE and TPV?
TPE is a mixture of rubber and plastic that can stretch under stress but snaps back into shape afterwards. TPV includes a blend of EPDM rubber and polypropylene which, when vulcanized, makes it highly resistant to heat and compression.
Our selection includes combinations of foam and hard TPV. Our TPV material has been tested accordingly for EN45545-2 R22/23 HL2.
Applications for TPV are much the same as those for TPE.
♻ BIO-TPE
Our selection also includes Bio-TPE, in which 65 % of fossil materials have been replaced with bio-based oils, making it an ecological alternative for TPE. Like TPE, Bio-TPE is a fully recyclable material with the same features as TPE.
Like regular TPE, Bio-TPE is a fully recyclable, non-toxic material, and it has the same excellent chemical resistances and hardness of 50-90 ShA in a full RAL color scale.
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PVC, EPDM, OR TPE?
In this section, we have shared some basic information about PVC and EPDM. These materials have been commonly used in profile manufacturing for a long time, but they are currently being replaced by more environmentally friendly alternatives.
Note: V.A.V. Group does not produce PVC or EPDM profiles. In most cases, they can be easily replaced by custom-treated TPE, TPV, or silicone materials.
PVC – POLYVINYL CHLORIDE
PVC is a synthetic plastic polymer known for its durability and versatility. It exhibits excellent resistance to chemicals, weathering, and UV radiation. PVC seals and profiles are rigid and provide stability, making them ideal for applications where structural integrity is crucial. Additionally, PVC is cost-effective, making it a popular and affordable choice in the construction industry.
Speaking of construction, PVC is commonly used in applications where structural stability is critical, such as window frames, door frames, and pipe fittings. Its rigid nature ensures long-term durability and resistance to wear and tear. PVC profiles are widely utilized in construction due to their affordability and ability to withstand harsh environmental conditions.
PVC typically has a higher melting point than TPE, making it more suitable for applications where high temperatures may be a concern. Conversely, TPE excels in low-temperature flexibility, ensuring effective sealing even in cold climates. However, TPE can be treated to withstand very high temperatures, up to the point of being fireproof, at which point it can effectively replace PVC.
EPDM
EPDM (Ethylene Propylene Diene Monomer) and TPE (Thermoplastic Elastomer) are both materials commonly used in various industries for their flexibility and durability, but they have distinct differences in terms of composition, properties, and applications.
EPDM is a synthetic rubber made from the polymerization of ethylene, propylene, and a small amount of diene monomers. It has a saturated polymer backbone, which gives it excellent resistance to environmental factors like UV radiation, ozone, and weathering.
Common applications for EPDM:
- Seals and gaskets in automotive, construction, and industrial applications
- Roofing membranes
- Electical insulation
- Radiator and coolant hoses
- Weatherstripping
EPDM properties:
- Excellent weather resistance
- Good heat resistance, with a temperature range of -50°C to 150°C
- Excellent electrical insulation properties
- Maintains its shape even after long periods of compression
- May become brittle over time
- Very limited hardness options
- No color alternatives; only black available
- Very robust, thin, or small profiles are difficult to produce
Limitations on EPDM usage
The composition itself does not play a significant role in the actual use of the profile, but it does in the manufacturing process. EPDM profiles are a lot harder to join together than TPE or TPV profiles, which means they cannot be “welded” together like our TPE/TPV profiles. To create angles or round shapes from an EPDM profile, the joint requires a joining block or an adhesive, which may become a weak link later on. TPE and TPV profile ends are simply heated, and the two ends are then pushed together to form a very reliable connection that requires no additional adhesives or other materials.
Enviromental issues
Even though it may lack some of EPDM’s features, TPE is more customizable than EPDM. TPV can be considered a highly functional hybrid between these two materials. In most cases, TPE can replace EPDM, which we have seen in the industry in the past years. One reason for this is that EPDM is typically processed using methods like extrusion, injection molding, and compression molding. It cannot be re-melted and reprocessed after curing. TPEs, however, are thermoplastic, which means they can be melted and reprocessed multiple times. They are well-suited for injection molding, blow molding, and extrusion processes.
This brings us to the biggest difference between EPDM and TPE, the recyclability. EPDM cannot be recycled, so it can only be disposed of as energy waste after its lifecycle has come to an end. It is also the main reason why several companies are looking for more environmentally-friendly alternatives, such as TPE or TPV. EPDM is often cheaper to produce, but because of its disposable nature, the total cost may actually become higher after waste management costs, whereas TPE and TPV can be melted and granulated after use.
ARE YOU LOOKING FOR A PVC OR EPDM REPLACEMENT?
The choice between PVC, EPDM, silicone, and TPE seals and profiles ultimately depends on the application’s specific requirements. Silicone has amazing temperature-resisting properties, PVC offers durability and structural stability, and EPDM offers weather resistance and insulation properties at a lower cost, while TPE provides flexibility, resilience, and environmental benefits. However, our modern solutions for TPE use have increased structural strength to the point where TPE can widely replace PVC and EDPM in most circumstances.
Understanding the performance characteristics and considering factors such as temperature resistance, environmental impact, and budget constraints will guide the selection process, ensuring the optimal choice for each unique application in the construction and manufacturing industries.
IS TPE BETTER THAN SILICONE?
Between TPE and silicone, there is no clear winner as to which one is “better” since they both excel in their own fields of use. Here is a clear side-by-side comparison of their properties:
Silicone | TPE/TPV | |
Hardness | Shore A 10-80 | 40 Shore A – 45 Shore D |
Color | Basic colors | Basic colors |
| RAL chart | RAL chart | |
| Metallic colors | Metallic colors | |
Operating temperature | -100 – +300 °C | -40 – +120 °C |
Diameter | 0-70 mm | 0-55 mm |
Optional properties | Stretch prevention cord | Stretch prevention cord |
| Foaming | Foaming | |
| 1-component or 2-component | 1-component or 2-component | |
| Fire-retardant | ||
| FDA-compliant food-grade silicone | ||
| Chemical durability | ||
Special properties | Heat-resistant silicone: up to +300 °C during short-term stress (7 days) | |
| Cold-resistant silicone: up to -100 °C | ||
| Fluorosilicone: resistant to various oils, solvents, and other chemicals during sustained contact | ||
| Electrically conductive silicone: ESD and EMI applications and low voltage switch and sensor applications | ||
| Platinum vulcanized silicone | ||
Applications | Not available | Fully recyclable |
As seen in the table, it’s a pretty even match between the two until the optional and special properties, that can be added to silicone profiles in our downstream operations. TPE’s advantage over silicone is that it can be produced in higher hardnesses than silicone and is fully recyclable, whereas silicone has to be disposed of by incineration at the end of its lifecycle*. Silicone easily beats other materials with its wide range of operating temperatures.
* Some recycling centers for silicone exist in Europe. They are few and far between, and the transportation of used silicone profiles from Finland to these centers would ultimately undo any environmental benefits of the recycling itself.
CUSTOM SOLUTIONS BY V.A.V. GROUP
In conclusion, the profile materials we provide all fit the needs and are widely used in construction, heavy industry, and transportation due to their easily customizable properties, high quality, and fast and flexible production times.
While we might be best known for top-quality seals and profiles for transportation, construction, and heavy industry, and those three categories are indeed the largest sectors we do business with, they are not the only ones. Our ability to create custom extrusion tools lets us produce products for a wide variety of uses, from brewing tanks and composter seals to food-grade feeding tubes for calves.
