How To Choose Between EPDM Seals and Silicone Rubber Seals

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These two related materials have different properties that lend themselves to specific applications.

However they are both useful and versatile materials.  The comparison below will help you understand the properties -and uses of each product.

In DTi&#;s 37+ years of experience, we have found that components fail because of errors at either the design stage and/or during installation.  So care has to be taken in not only choosing the correct material for the job but also in ensuring those materials are installed correctly.  Failure at either step will make or break the success of the component in operational usage. 

EPDM

EPDM &#;Ethylene Propylene Diene Monomer&#; is a synthetic rubber elastomer. It&#;s stable, saturated polymer backbone gives it the toughness that makes it widely used in construction for seals and roofing and in the auto industry for window seals, door seals, and gaskets for electrical applications.

Key attributes

• Abrasion and tear resistance
• Stands up well to up to harsh weather conditions &#; rain, sleet, snow, ozone and UV.
• Its weak point is temperature resistance as it will deform at higher temperatures.
• EPDM has a shorter life span than silicone, so will need to be replaced more frequently.

Silicone Rubber

Silicone rubber (SIR), -Polydimethylsiloxane- is an inorganic polymer based on quartz sand. It is composed of silicon, carbon, hydrogen, and oxygen. It is used extensively in industries from rail, aerospace, food service, automotive, electronics, medical devices and implants, and even toys.

Key attributes

• Outstanding resistance to ozone and weathering although EPDM is better for UV & water resistance
• Resistant to high temperatures &#; does not deform or lose its properties compared to EPDM.
• It can be sterile and food safe so is widely used in the medical/food service industry for tubing, seals & gaskets.
• Temperature resistance, sterility & longer life cycle means it is mostly seen as superior to EPDM although it is more costly.

Let&#;s look at DTi&#;s product attributes in more detail.

Temperature

Temperature resistance is critical in applications that subject components to wide temperature ranges. Think ovens.   At high temperatures you do not want your rubber seal to melt, deform or become brittle with cold, either extreme could cause it to fail during operation with potentially disastrous results for the equipment and its output.

EPDM should be used if your application between -40°C to 121°C (250°F).

Silicone should be used if your application between -40°C to 200°C (392°F) some formulations can go to 270°C (518°F).

Caveat emptor: we present DTi product specs here however there is variability in temperature ratings by formulation and supplier so carefully check product specs against your application needs.

Elongation/Tear Resistance

Different applications will require hardness/stiffness while others will require the product to flex and stretch to accommodate changing conditions.  You&#;ll want to consider how much a seal or gasket should be able to indent and change shape under operational conditions in order to avoid failure.

Silicone stretches more than EPDM and can elongate up to 800% and has a high tear resistance.

As a result it is used as vacuum membranes and presses that help form and bond composites under extreme pressure.

Temperature resistance also plays a part here.  DTi silicone & EPDM will stay flexible to -40°C -before becoming brittle.

Oil resistance

Both materials tend to swell if exposed to oil for long periods.  However silicone has a better resistance to oil and so is preferred if oil exposure is an issue e.g. in auto engines or marine engine rooms.

Environmental

If the seal/component is to be outdoors its environmental resistance will be important. Some rubbers will crack when continuously exposed to ozone and UV which will impact performance.   Both EPDM and Silicone have excellent resistance to weather, ozone and UV although EPDM is better for water resistance

Tear Strength

Tear strength can be important when the component is subjected to flex forces that could make it split or tear. EPDM has good tear strength and is more durable than silicone.  However, the flip side of that is that silicone is more flexible and can also manufactured to have higher levels of tear resistance and elongation

At a glance: EPDM vs Silicone

DTi ProductsEPDMSilicone Temperature-40˚C &#; 121˚C/ (-40˚F &#; 250˚F)-40°C to 200°C (-40˚F &#; 392˚F) Compression setGoodExcellent Weather resistance Ozone/UVExcellentExcellent Water ResistanceExcellentVery Good Tensile strengthApprox. 8 MPaApprox. 5 MPa Abrasion resistanceGoodPoor Electrical resistanceGoodFair Oil ResistanceFairGood Flame retardantGoodExcellent Avoidhydrocarbon fuels,
concentrated acids,
halogenated solventshydrocarbon fuels,
alkalis and acids,
steam over 121°C/249°F,
trichloroethylene,
aromatic hydrocarbons.

DTi Silicone and EPDM

DTi has a range of seals in different formulations -Silicone and EPDM, plus a lower cost variant that is EPDM/PVC to meet your application needs.  They are available off the shelf in many profiles and we can produce hundreds more with short lead times.  All production is US made which can help with local &#;Buy America&#; sourcing requirements.

Pre-cut lengths, assembly kits, and one-piece (picture frame type) vulcanized assemblies are available with pre-joined film bonded and/or vulcanized terminating ends.

DTi will build custom seals with clients using Customized Finite Element Analysis (CFEA) to digitally test prototypes before production &#; which speeds up reliability and delivery to you.

Seals are just one part of DTi&#;s product range which includes high-performance wire protection grommet edging, fiber management modules, braided cable sleeving, and edge trims.

For more information on Seal-Fast Silicone seals go here

For EPDM seals go here

Get free samples go here

Seal strips are typically made of polymers and elastomers produced from extrusion molding. There are hundreds of seal strip shapes available in the market. Why such diversity of shapes? Because each industry and application has different requirements for different seal shapes. Customers who download our product catalog know about various seashore rubber products.

This article will only discuss the most popular and common seal strip applications. We will also highlight the specific application for each seal strip shape. It is important to note that you can directly visit the product&#;s profile by clicking on the link attached to the respective seal strip shape names.

Different Seal Strip Shapes

This diversity of the seal strip shapes is the wide range of applications. Seal strips are famous for eliminating noise and vibration. It also helps seal gaps around the doors and windows or prevents contaminants from entering vehicles or houses. On the other hand, we know that these applications&#; infrastructure types are also vast. So, every kind of structure requires a unique seal strip shape.

We have covered all types of seal shapes for most sealing applications for any infrastructure. Seashorerubber offers exclusively designed seal shapes. These seal strips are perfect for garage doors and windows to automobile windshields and panes. The specially designed plastic and rubber compound for each product ensures long-lasting protection. The following list will discuss the twelve most popular seal strip shapes.

U Shape Seal Strips

This type of seal strip usually looks like the English letter &#;U&#; on the cross-section of the product. You may find several types of U shape seal strips. The types are channel seals, section strips, solid seals, silicone rubber seals, channel weather Stripping, etc.

Advantages:

1. Aging resistance
2. Waterproof
3. Good resilience
4. Anti-collision
5. Wear-resistant
6. Flame retardant
7. Long life
8. Anti-stress
9. Acid and alkali resistance
10. Anti-UV

Applications:

U shape seal strips are prevalent in medical industries, scientific research, and food processing. It is also famous for weatherstripping cabinets and apartments. Moreover, the additional applications include optical fiber cables, electrical parts, hydraulic tanks, etc.

• Car
• Chemical industry
• Meter
• Mechanical
• Furniture
• Electronic appliances

This type of seal strip shape is one of the most popular weather stripping in most applications. A typical D shaped seal strip has a half-moon bulb and a flat bottom. The half-moon bulb withstands high pressure. On the other hand, the flat bottom part contains adhesive, which helps with sticky attachment. D shaped seal strip materials, usually sponge rubber. It can ensure superior sealing under pressure.

Advantages:

1. Thermal insulation
2. Waterproof
3. Super elastic
4. Cushioning
5. Non-absorbent
6. Weather resistance

Applications:

This seal shape is prevalent in a mobile equipment cabin or machine enclosure. On the other hand, D shape seal strips are also used to seal gaps between long sheet metal and the other surface. Other applications include door edges, window seals, automotive seals, hydraulic equipment, etc.

• Car
• Doors and windows
• Mechanical

E Shape Seal Strips

E shaped seal strips usually resemble the small English letter &#;e&#; at the cross-sectional area. Like D shape seal strips, the half-moon part of the E shape seal supports high compression. The flat bottom helps in attachment with the projected application surface. E shape seal strips usually come as extruded silicone rubber for a channel, section strips, and weatherstripping.

Advantages:

1. Tightness
2. Heat resistant
3. Aging resistance
4. Shockproof
5. Sound insulation

Applications:

E shape seal strips are trendy in food processing applications. In this application, mechanical fastening is more efficient and safer than adhesive. E shape seal strips are also famous in automotive, high-voltage insulation, and cabinet door seals. Also, some military applications might require this type of seal strip.

• Steel doors and windows
• Aluminum alloy doors and windows
• wooden doors and windows

T Shape Seal Strips

This seal shape has a flat surface or curved top and a &#;T&#; shape cross-section. This type of seal shape is widespread and a great sealing agent to prevent leakage from gaps or cracks. T shape seal strips may include channel seal strips, flat T seals, section rubber strips, rubber trims, and weatherstripping. This type of seal strip material may consist of natural rubber, neoprene, EPDM, nitrile, and SBR.

Advantages:

1. Aging resistance
2. Pollution-free
3. Long life
4. High and low-temperature resistance
5. Good sealing effect
6. Corrosion resistance
7. Good resilience
8. Tear resistance
9. Waterproof

Applications:

You will get efficient and thoughtful service from I-ECO.

T shape seal strips are widely popular in hydraulic systems where fluid leakage is a concern. It is also prevalent in doors and windows, electrical cabinets, food processing, etc.

• Shipbuilding industry
• Instrumentation
• Telecommunications Industry
• Medical career

P Shape Seal Strips

This seal shape has one flat surface and a full moon part. It looks like the English capital letter &#;P&#; at the cross-section of the seal strips. P shape seal strips come as P shape seals, channel seal strips, section strips, and P shape weatherstrips. These types of seal shapes offer better performance and flexibility.

Advantages:

1. Weather resistance
2. Non-absorbent
3. Thermal insulation
4. Cushioning
5. High and low-temperature resistance

Applications:

P shape seal strips are prevalent as weather stripping in many industries. This seal shape is also popular in food, dairy, and pharmaceutical applications. Besides, this seal shape is also used in the laboratory where sealing is crucial for dust control.

• Precision machinery
• Medical equipment
• Furniture
• Vehicle
• Ship
• Pipeline
• Lamps

H Shape Seal Strips

This seal shape usually includes H shape silicone rubber seals, H rubber channel seals, and H shape section rubber seals. This seal strip type is traditionally used for high-temperature resistance ranging from -65°F to +400 °F.

Advantages:

1. Preservative
2. Aging resistance
3. High and low-temperature resistance
4. Not easily deformed
5. Long-lasting
6. Insulation
7. Good elasticity

Applications:

H shape seal strips are prevalent in various applications such as rail, aerospace, and civil engineering. Besides, it is also widely used in food, dairy, and HVAC applications. Moreover, H shape seal strips are also used in sound and heat insulation.

• Mechanical
• Doors and windows
• Car

L Shape Seal Strips

L shape seal has two consecutive flat surfaces. It looks like the English capital letter &#;L&#; at the cross-sectional area. These seal strips usually come as an L shape rubber seal strip, L shape rubber trims, and L shape weather stripping. Depending on your application, you can decide the material&#;s properties from seashore rubber.

Advantages:

1. Aging resistance
2. Good sealing performance
3. Sound insulation
4. Wear resistance
5. Anti-collision
6. Weather resistance
7. Insulation

Applications:

L shape seal strips are prevalent in food, dairy, and pharmaceutical applications. Besides, L shape seal strips are also perfect weather stripping for buildings, cabinets, and automobiles.

• Mechanical
• Car
• Container

J Shape Seal Strips

This seal shape comes in different forms, such as a J-shaped strip with thin and thick walls, flat and curved. Like other shapes, J shape seal strips also have diversity in selecting and matching varied materials and colors.

Advantages:

1. Anti-corrosion
2. Durable
3. High and low-temperature resistance
4. Strong climate adaptability

Applications:

J shape seal strips are popular in industries where temperature, ozone, electricity, and fungus are concerned. Moreover, these seal strips provide great flexibility and are perfect for electric insulation. Other applications include automobile weather protection, ship container sealing, marine, and aerospace.

• Car doors and windows
• Ship
• Aerospace

V Shape Seal Strips

It is the most popular seal strip widely used in weather protection in apartments and buildings. V shaped seal strips are also known as tensile seals. These seal strips are durable. Above all, v strips are prevalent in most building sealing applications.

Advantages:

1. Good sealing performance
2. Long life
3. Impact resistance
4. Shock absorbing
5. Insulation
6. Good elasticity

Applications:

The common application of v strips or v shape seal strips is weather protection, commonly found in most buildings and apartments. Besides, automobiles, electric cabinets, and hydraulic systems also require v strips or v shape seal strips.

• Car
• Hydraulic system
• Building

Oval Shape Seal Strips

This type of seal shape has a solid oval shape at the cross-section. The typical materials for this type of seal strip are EPDM, silicone rubber, and other elastomers. These materials are highly versatile and provide excellent sealing capabilities. Because of its tangible properties, it can withstand high compression pressure. The typical hardness of this type of seal strip is from 20 shore A to 80 shore A. Shore is a unit of the hardness of a material.

Advantages:

1. Weather resistance
2. Anti-aging
3. Shockproof
4. Dust-proof
5. Pest control
6. Anti-UV
7. Chemical resistance
8. High and low-temperature resistance
9. Good resilience
10. Sound insulation

Applications:

This type of seal strip is widely popular in chemical industries. Besides, oval shape seal strips are also prevalent in hydraulic systems, electrical cabinets, etc.

• Pipeline system
• Car
• Mechanical
• Household appliances
• Toy

Bulb and Double Bulb Shape Seal Strips

These seal shapes typically have a single and double half-moon structure at the top and a flat surface at the bottom. As the name implies, these seal strips look like single or double bulbs at the cross-section. Most industries aim to use these seal strip shapes for water and chemical resistance.

Advantages:

1. Good elasticity
2. Shockproof and waterproof
3. Environmental Safety
4. Aging resistance
5. Alkali resistant
6. Sound insulation
7. Insulation
8. Dust-proof

Applications:

The typical use of bulb seal strips is between the door and the wall, either on the hinge or strike side. These seal strips are also popular in chemical industries, water treatment, food processing, etc.

• Car windows
• Chemical industry
• Food processing

Triangular and Trapezoid Shape Seal Strips

Finally, these two seal strip shapes also made great demand in most industries. These seal strips are typically solid in form. Moreover, they can withstand temperatures from -65 °F to 450 °F. These seal strips offer excellent electric and heat insulation.

Advantages:

1. Stretch resistance
2. High and low-temperature resistance
3. Insulation
4. Withstand voltage
5. Wear resistance
6. Weather resistance

Applications:

These seal strips are popular in the construction, automotive, marine, and aviation industries.

• Architecture
• Car
• Ship
• Food

Summary

Seal strips or weather stripping come in hundreds of shapes and sizes. All these sizes and shapes are suitable for specific applications. Each of the forms has a unique function and capabilities. We have tried to demonstrate the most popular seal strip shapes that you would find in most applications. However, there are other complex and customized seal strip examples. We did not bring those examples because we wanted to make this article relevant to the most common seal strip shapes.

Seashorerubber is a leading plastic and rubber seal strip manufacturer worldwide. This company manufactures all seal strip shapes and offers customers customized shapes and sizes. The factory&#;s seal strips are high-quality and long-lasting. Besides, they can also withstand high pressure and temperature. Silicon rubber seal strips are excellent chemical, heat, and electric insulators. This company focuses on all seal strips you may need for any application. You are welcome to consult at any time.

The company is the world’s best EPDM Automotive Seal Strip Supplier supplier. We are your one-stop shop for all needs. Our staff are highly-specialized and will help you find the product you need.