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Unveiling the Elasticity Dynamics: A Deep Dive into Silicone Rubber’s Rebound Resilience

When any elastic material is exposed to an impact load, it will initially deform before bouncing back to its original shape. When this occurs, part of the initial energy delivered by the impact is returned as mechanical energy, and a certain portion is dissipated as heat. From this, the rebound resilience is defined as the ratio of mechanical energy returned to the initial mechanical energy exerted from the impact. Higher rebound resilience indicates stronger elasticity, resistance to deformation and a stronger capacity to bear impact loads. However, for some applications such as vibration dampening, lower rebound resilience may be more beneficial.

Testing for this property is typically performed by dropping a standardized pendulum at a set height and speed onto a material sample, as described by standards including ISO 4662 and DIN 53512. After the pendulum impacts the rubber, the rubber will deform before pushing back against the pendulum, returning mechanical energy. Here, the rebound resilience can be quantified by the ratio of the pendulum rebound height to the initial release height.

Compared to other elastomers silicone rubber exhibits intermediate rebound resilience values, typically between 30 and 70 %. Typically this is better than some elastomer families such as butyl or styrene-butadiene rubber, but worse than elastomers such as natural rubber or polyurethane. Notably, silicone rubber can be produced to have high rebound resilience in a range of hardness values. Thus, depending on the application, silicone rubber can be an excellent choice for dampening applications or dynamic applications where higher rebound resilience is more important.

While rebound resilience is one method of quantifying material elasticity, another complementary parameter that characterizes a material elasticity is the material’s compression set. This property describes how readily the shape of a material is permanently affected when subject to prolonged deformation. More information on silicone’s outstanding compression set is available on our articles page.

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Carbon-based vs Silver-based Electrically Conductive

Carbon-based vs Silver-based Electrically Conductive Silicone

Standard silicone elastomers are electrically insulating, however with the right chemistry and speciality materials they can be made electrically conductive. 

The most common ways of making electrically conductive silicone is by combining it with reinforcing filler materials with strong electrical conductivity. These can include silver coated glass/graphite/nickel/copper/etc, pure silver nanoparticles, or more commonly conductive carbon black. Silver based conductive filler provides extremely low electrical resistivity profiles up to 0.002 Ohm/cm and provides electromagnetic pulse (EMP) shielding properties for highly specialized applications. However, these silver-based conductive silicone components cannot be produced via extrusion and cannot be directly produced at Jehbco. 


Conductive Component Pros Cons
Silver or Metal Based Nanoparticles
  • Excellent EMP shielding capabilities
  • Extremely high electrical conductivity (resistance ~ 0.002 Ohm/cm)
  • Excellent temperature stability (-50 to 200 °C)
  • Extremely expensive
  • Poor mechanical strength 
  • Cannot be produced via extrusion
  • High density (~ 3 g/cm3)
Conductive Carbon Black
  • High electrical conductivity (resistance ~ 2 Ohm/cm)
  • Good mechanical properties
  • Producible via extrusion
  • Low cost compared to other conductive grades
  • Excellent temperature stability (-50 to 200 °C)
  • Standard silicone density
  • Intrinsically flame retardant
  • Weaker EMP shielding capabilities
  • Conductivity still high, but not as good as silicone with silver based conductive components


For extrusion silicone materials, conductive carbon black is commonly used to create highly conductive silicone materials. Conductive carbon black is a speciality grade of carbon that is manufactured entirely differently from carbon blacks used in pigmentation, which provides it with extremely useful properties including high electrical conductivity. Interestingly, the use of carbon black necessitates the use of more resourceful chemistry to facilitate processing. High loadings of carbon black typically interfere with standard peroxide silicone curing systems, due to incompatibility with the most common catalyst used in extrusion processing (2,4 dichlorobenzoyl peroxide). Thus, platinum curing systems must be used in all carbon loaded electrically conductive silicone articles processed via extrusion. 


By utilizing elevated quantities of reinforcing and electrically conductive carbon black, extremely low electrical resistivity of < 2 Ohm/cm are commonly achieved, while maintaining excellent mechanical integrity. In addition to providing electrical conductivity, the addition of conductive carbon black provides increased fire retardant properties without requiring supplementary fire retardant additives. Carbon black conductive silicone components find frequent application in sensors and electrical components, and can also be used as anti-static materials including sleeving to discharge static build-up.


At Jehbco, we offer electrically conductive silicone in from 50 to 70 ShA hardness exhibiting extremely low electrical resistance (<2 Ohm/cm), and can be formulated to other hardness grades based on customer requirements. All Jehbsil conductive silicone is jet black in colour. For another article comparing conductive silicone to standard silicone, see: https://jehbco.com.au/silicone-electircally-conductive-silicone/

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RoHS: “Restriction of Hazardous Substances” in Silicone Parts for Electrical Products

The RoHS (Restriction of Hazardous Substances) regulation derives from the European community joint efforts to regulate and restrict the use of hazardous substances in electrical and electronic products to protect the environment and human health.

The directive adopted on July 1 of 2006 has undergone updates until the most recent RoHS 3 – directive 2015/863 – where was established that all electrical or electronic products, manufactured or distributed within the European community, should not exceed the maximum concentration for each substance on the table below:


Restricted Substance Maximum Level allowed
Cadmium (Cd):  < 100 ppm     (0.01%)
Lead (Pb):  < 1000 ppm   (0.1%)
Mercury (Hg):  < 1000 ppm   (0.1%)
Hexavalent Chromium (Cr VI):  < 1000 ppm   (0.1%)
Polybrominated Biphenyls (PBB):  < 1000 ppm   (0.1%)
Polybrominated Diphenyl Ethers (PBDE):  < 1000 ppm   (0.1%)
Bis(2-Ethylhexyl) phthalate (DEHP):  < 1000 ppm   (0.1%)
Benzyl butyl phthalate (BBP):  < 1000 ppm   (0.1%)
Dibutyl phthalate (DBP):  < 1000 ppm   (0.1%)
Diisobutyl phthalate (DIBP):  < 1000 ppm   (0.1%)

Last update July 22nd, 2021.


The substances above can be carcinogenic, mutagenic, toxic and bio accumulative for the human body. In addition, they can produce highly toxic transformation products when mixed with other components during disposal or recycling.

Electrical products that are in contact with food and beverages should comply with the RoHS directive. Not only because people will consume the items inside but also because they can be in use daily. Microwaves, refrigerators, blenders are examples of appliances where silicone gaskets should comply with RoHS.

Similarly, electrical appliances in constant contact with water for example, washing machines or heaters, should not introduce harmful chemicals such as lead, mercury or cadmium into pipes or drainage systems to avoid contamination of water sources and other negative impacts on the environment. In those cases, silicone tubing and door gaskets should also comply with RoHS.

The silicone products manufactured at Jehbco have countless applications within the electrical and electronic industry, most recently providing the manufacture of medical devices and electrical appliances with silicone gaskets, washers and membranes. That is why Jehbco remains in constant communication with raw material suppliers who provide the company with the RoHS declarations and the corresponding raw materials composition.

Whether they contain RoHS, limited or prohibited substances, Jehbco identifies the current requirements of the applicable regulations and will be happy to provide their customers with the necessary declarations.






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Adhesive Peel Strength Testing for Silicone Adhesives

At Jehbco, we are constantly finding innovative ways to use the products we produce to suit your needs. The application of silicone elastomer profiles can be extended in combination with adhesives for applications across many industries.


Adhesive peel testing can assist in selecting the right silicone adhesive for your application. Comparing peel adhesion, tensile strength, and shear resistance provide a comprehensive answer to how suitable an adhesive is to a certain application. If the adhesive strength is lower than the requirement, the bond may wear away and lose adhesion.


Adhesive peel strength is determined through the constant load per unit width required to separate the adhesive and substrate in kilonewtons/metre. This force is applied to an edge of the adherend and the substrate and is determined from the average value of the flat portion of the force-extension curve [1].


A simple qualitative test can be done by hand is the ‘pull test’, which is to pull the silicone with reasonable strength. For a more detailed quantitative result, standardized adhesive peel tests may be conducted on clean, contaminant free substrates to determine the force required to separate the substrate and the adherend[2]. The most typically used tests are:

  1. The T shaped peel test (ASTM D1876[3]) is the most widely used peel test for thin-gauge metal adherends.
  2. The 180-degree peel test (ASTM D903 [4]) requires flexible adherends that may be bent 90 degrees without breaking or cracking.
  3. The 90-degree peel test (ASTM 6382 [5]), which also required flexible adherends.


At Jehbco, we have the capability to conduct tests according to ASTM 6382. The testing rig is illustrated below. The use of a machine ensures controlled peel rates that reduce scattering and lead to more accurate results [4].


Major factors that affect the measurement of adhesion are [5]:

  • Selection of the peel test
  • Pull speed
  • Temperature and humidity conditions
  • Substrates and adherend material, interfacial characteristics, and thickness
  • Adhesive choice
  • Aging condition (typically 4hrs, 7 days, and 14 days)



  1. B. Duncan, “Developments in testing adhesive joints,” in Advances in Structural Adhesive Bonding, Woodhead Publishing Series in Welding and Other Joining Technologies, 2010, pp. 389-436.
  2.  tesa, “What’s the deal with peel (peel adhesion, that is)?,” 2016. [Online]. Available: https://www.tesa.com/en-au/wikitapia/what-s-the-deal-with-peel-peel-adhesion-that-is.html.
  3. ASTM International, “ASTM D1976: Standard Test Method for Peel Resistance of Adhesives (T-Peel Test),” ASTM, West Conshohocken, PA, USA, 2015.
  4. ASTM International, “Standard Test Method for Peel or Stripping Strength of Adhesive Bonds,” ASTM International, West Conshohocken, PA, United States, 2017.
  5. ASTM International, “Standard Test Method for 90 Degree Peel Resistance of Adhesives,” ASTM International, West Conshohocken, PA, USA, 2003.
  6. T. S. J.K. Dennis, “Physical and mechanical properties of electrodeposits and methods of determination,” Nickel and Chromium Plating (Third Edition), 1993.
  7. S. R. Meyer, “Adhesion – Considerations, Testing and Interpretation,” 3M, Minnesota USA, 2015.
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Flame Retardant Silicone Products for Railway Industry

EN 45545-2_R22 European standard

EN 45545 is a European standard that specifies the “fire performance requirements for materials and product used on railway vehicles”[1] in order to protect passenger and staff in railway vehicles in the event of a developing fire on board[2]. The part of the standard that applies to Jehbco products is R22 which has a section about the requirements for interior seals[3]. This standard section is now used in replacement of BS 6853 which was a smoke safety standard for the rail industry[4].

The methods to perform testing are detailed in the standard. It consists of 3 tests that are used to establish product performance versus these product requirements: 

  1. Oxygen index (EN ISO 4589-2): this test determines the burning behaviour at ambient temperature[5]. It is defining the minimum concentration of oxygen in a mixture of oxygen/nitrogen that will support flaming combustion.
  2. Smoke density (ISO 5659-2): this test measures the smoke production from the exposed surface of materials or composites[6].
  3. Smoke toxicity (NF X70-100): this test quantitively determines the thermal decomposition and combustion of materials decisive for the toxicity of the fire environment[7]

The standard defines three hazard levels: HL 1, HL 2 and HL 3; HL1 being the lowest requirement and HL 3 the highest.  The performance requirements on EN 45545-2 for each of these tests is summarized below:

Table 1: Summary of test methods

Test Method Parameter Unit Maximum or minimum HL 1 HL 2 HL 3

Oxygen Index 

(EN ISO 4589-2: OI)

Oxygen content % Minimum 28 28 32

Smoke Density

(EN ISO 5659-2: 25 kWm-2)

Ds max


Maximum 600 300 150
Smoke Toxicity

(NF X 70-100-1 & -2 600°C)

CITNLP dimensionless Maximum 1.2 0.9 0.75


Ds max is the maximum optical density in the test chamber

CITNLP is the conventional index of toxicity for non- listed product


Jehbco is proud to inform that their Jehbsil black flame retardant products with hardnessess going from 30 to 90 Sh A have successfully met the requirements of the PN  EN45545 2 + A1:2015 standard for R22 and R23 at the HL 1, HL 2 and HL 3 hazard levels in November 2020.



  1.  European Committee for standardization. EN 45545-2:2020 standard. “Railway applications – Fire protection on railway vehicles – Part 2: Requirements for fire behavior of materials and components”, August 2020
  2. European Standard. “Set DIN 45545-1-7- Fire protection on railway vehicles”. Viewed on 31st March 2021https://www.en-standard.eu/set-din-en-45545-1-7-fire-protection-on-railway-vehicles/
  3. DGE smart speciality chemicals, “EN 45545-2 European railway standard for fire safety”, viewed on 31st March 2021. https://dge-europe.com/en-45545-european-railway-standard-fire-safety/
  4.  Nathan White, CSIRO , “Fire Performance of Passenger Trains”, FPA Australia, viewed on 31st March 2021. fpaa.com.au/media/229521/d1-fse-p5-white.ppt.pdf  
  5. International Standard Organisation, “ISO 4589-2:2017(en). Plastics — Determination of burning behaviour by oxygen index — Part 2: Ambient-temperature test”. Viewed on 31st March 2021.https://www.iso.org/obp/ui/#iso:std:iso:4589:-2:ed-2:v1:en 
  6. International Standard Organisation, “ISO 5659-2:2017 Plastics — Smoke generation — Part 2: Determination of optical density by a single-chamber test”, viewed on 31st March 2021. https://www.iso.org/standard/65243.html
  7. Sychta laboratorium, “the toxicity test for thermal decomposition and combustion products of materials with methods according to NF X70-100-1, NF X70-100-2 and PN-EN 45545-2”. viewed on 31st March 2021. http://www.sychta.eu/en/nf-x70-100-1.html
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REACH Standards and European Chemical Risk Regulations

Reach, The European Chemical Risk Regulation

At Jehbco Silicones we strive to be up-to-date and compliant with international quality standards to meet our customer’s expectations. In order to adhere to regulations that are stipulated by the European Union Jehbco needs to evaluate and control our raw materials ensuring they comply with the REACH standard.

REACH Standards and European Chemical Risk Regulations

Chemical risk regulation in factories

REACH is an acronym for “Registration, Evaluation, Authorization and Restriction of Chemicals”. It is a standard created by the European Union that drives the creation of more information about the risks of chemical exposure. The principal objective of the standard is to guarantee a high level of protection for human health and the environment.
In order to comply with REACH, companies must identify the hazards associated with the chemicals they use or manufacture and notify the European Chemicals Agency (ECHA) of these hazards. If there is an unacceptable risk to human health or the environment from the manufacture, use or commercialization of substances at a community scale, restrictions will be established in relation to their use.


Only registered substances to the ECHA can be commercialized in the European Union including chemicals used in industrial processes and those used on a daily basis, such as cleaning products, paint, etc. This is why the standard affects not only producers of goods but also importers of goods outside of the European Union. This includes companies who produce goods or services where chemicals are being used indirectly and are not part of the final product, such as those that are used in the manufacturing process at Jehbco.
The process to comply with ECHA and the REACH standard involves the compilation of technical documentation and especially the characterization of the substance. Broadly, the characterisation of a substance is where a material’s structures and properties are proved and measured. Through this process companies gain more knowledge about the properties and effects of chemicals, ensuring that risks are adequately controlled and that hazardous materials can be progressively replaced by better alternative technologies.
REACH implementation imposes greater responsibility as it encourages companies to communicate the best and safest way to handle chemicals. Just in New South Wales Safe work NSW has reported that there have been more than 6500 injuries in workplaces as a result of poor handling or storage of hazardous chemicals. Eight people died and more than 250 are now permanently disabled in the last 4 years.



  1. European Chemicals Agency ‘Understanding REACH’, https://echa.europa.eu/regulations/reach/understanding-reach
  2. SafeWork NSW, Hazardous chemicals, https://www.safework.nsw.gov.au/hazards-a-z/hazardous-chemical
  3. European Chemicals Agency ‘REACH, CLP and biocides for non-EU companies’ https://echa.europa.eu/support/getting-started/enquiry-on-reach-and-clp
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Red Car – Jehbco Silicones

ASTM D2000 Rubber Classification

Rubber compounds, such as silicone, can be formulated to have a wide variety of physical characteristics. The ASTM D2000 Standard Classification System for Rubber Products in Automotive Applications, often shortened to ASTM D2000, is a standardised method used to specify the required physical properties of a vulcanised rubber product.


The ASTM D2000 classification takes the form of an alpha-numeric call out, an example of which can be seen below.


ASTM D2000 M5 GE 706 A19 B37 EO16 Z1


The table below contains the different components of the callout using the callout above as an example, along with a brief explanation of each component.

Table 1: Outline of ASTM D2000 Callout Components

Component Location in Callout Explanation
Unit of Measure ASTM D2000 M5 GE 706 A19 B37 EO16 Z1 Indicates the use of metric or imperial units in the callout
Grade Number ASTM D2000 M5 GE 706 A19 B37 EO16 Z1 Indicates the quantity of additional requirements to be tested for the material
Type and Class ASTM D2000 M5 GE 706 A19 B37 EO16 Z1 Indicates the heat resistance (type) and oil resistance (grade) requirements of the material
Hardness ASTM D2000 M5 GE 706 A19 B37 EO16 Z1 Indicates the hardness requirement of the material
Tensile Strength ASTM D2000 M5 GE 706 A19 B37 EO16 Z1 Indicates the minimum tensile strength requirements of the material
Suffixes ASTM D2000 M5 GE 706 A19 B37 EO16 Z1 Indicates any additional requirements of the material, exclusive of the standard requirements above (See Table 2)
User Defined Suffixes ASTM D2000 M5 GE 706 A19 B37 EO16 Z1 Indicates any user-defined additional requirements of the material that are not outlined in the standard suffix naming system.


Table 2: Naming Convention of Standard Suffixes

Suffix Letter Test Required
















Heat Resistance

Compression Set

Ozone or Weather Resistance

Compression-Deflection Resistance

Fluid Resistance (Aqueous)

Fluid Resistance (Fuels)

Low Temperature Resistance

Tear Resistance

Flex Resistance

Abrasion Resistance


Flammability Resistance

Impact Resistance

Staining Resistance


Any special requirement, which shall be specified in detail.


The ASTM D2000 Rubber classification can even be used to differentiate different silicone compounds. For example, the line callout below can be used to describe a hard, high tear strength silicone grade


ASTM D2000 M2 FC 709


Alternatively, the line callout below can be used to describe a soft, high temperature resistant silicone grade.


ASTM D2000 M3 GE 310 A12

The ASTM D2000 rubber classification system is an extremely robust and efficient method of classifying vulcanised rubber materials such as silicone. Jehbco can manufacture compounds to meet most silicone-based ASTM D2000 line callouts.


Please contact our sales team if you would like more information.

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Computer Code

Working Towards Industry 4.0

What is Industry 4.0?

Industry 4.0 is an industry renaissance revolutionising manufacturing, known as the fourth industrial revolution. 

It represents a shift within industry toward smarter, digitised systems allows for more control within production lines1. This control is enabled by building smarter communication systems between machines, utilising Internet of Things (IoT) and Machine Learning (AI) from data collection within the product line en masse. Analysing and systematically extracting data from the product line in quantities large enough to require specialist data processing and handling is Big Data within the product line1 needing machine learning for data processing.

Industry 4.0 has a heritage defined in revolution from[1]:

  • Industry 1.0 – Mechanisation, steam and water power.
  • Industry 2.0 – Mass production and electricity.
  • Industry 3.0 – Electronic and IT systems automation.
  • Industry 4.0 – Cyber physical systems.

Why is it important?

Using IoT and AI in communication processes within manufacturing; calculations can be made quickly and efficiently guaranteeing responses within specified time constraints, otherwise defined as “real time”, with continuous machine operation monitoring[2]. This can speed up processes and filter superfluous data ensuring cumbersome processes within the product line are kept to a minimum. 

Real time systems allow continuous monitoring and adjustments, increasing speed and matching customer demands in an economy where transactions are digital and increasingly automated, defining a real-time economy. This continual digitisation of business transactions allows adjustment to the supply chain in real time, when needed, for both manufacturer and client. Costs, company alignment and product value, all benefit from real time actioning and digitisation of transactions.

By digitisation and digitally quantifying process within the supply chain, efficiency within the processes allow human power in manufacturing to shift. This allows human power to provide more support to the product line. This shift in resources allows for: 

  • Efficient organisation actioning and agility in structure to adapt for client needs.
  • Better building of company culture.
  • Interdepartmental connectivity.
  • Maximising production outcomes.
  • Deeper understanding of client needs for better problem solving2

By making this shift, production can increase, machine downtime can decrease and customers can receive goods on time, when and where they need it most.

When machine repair is required, smart systems can assist with fast diagnosis and action on the repair. Integrating Augmented Reality (AR) with hardware can make repair logs and finding what needs repair quick and easy2. AR is the next step in training staff to make repairs and assessments on machines accessible and agile to business and staff needs.

How is Jehbco integrating Industry 4.0 into practice?

Since becoming a member of the Australian Manufacturing Growth Centre (AMGC) Jehbco has been gradually incorporating more Industry 4.0 practices into our manufacturing systems. The AMGC has supported higher R&D spending, Information & Communication Technology (ICT) spending and collaborative efforts between manufacturers and research institutions fostering Australia’s Industry 4.0 progress[3].


Jehbco Silicones is still working towards fully integrating into the business. Starting with machine upgrades for digitised capture of data. These upgrades employ small localised computers designed to take specific inputs to produce specific outputs. These small computers are Programable Logic Controllers (PLC’s) and run many different machines. 

By integrating machine PLC’s to capture run time data we can build automated production and factory schedules allowing for increased monitoring of production and systems output.

Through capturing data and putting it to use we are initiating automated factory scheduling. Looking toward building a future of predictive scheduling and production analysis to optimise factory output, product lead times and delivery in full on time.


If you would like to learn more about the integration of Industry 4.0 into our manufacturing processes please contact us.


  1. Dassault Systèmes 2021, Digitalization and Continuity. Dassault Systèmes, Viewed 02 February 2021, https://discover.3ds.com/digitalization-and-continuity?utm_medium=cpc&utm_source=google&utm_campaign=202101_glo_sea_en_op51508_labl_generic_manuf_ww_bmm&utm_term=manuf-industry4.0&utm_content=search&gclid=Cj0KCQiAx9mABhD0ARIsAEfpavTScy6bKhE-u9lUY_efVdw5BNmG6PypTTIOu8QGBGeXcbo4q0a-K18aApOTEALw_wcB
  2. i-Scoop 2021, Industry 4.0: the fourth industrial revolution – guide to Industrie 4.0, i-Scoop, Viewed 02 February 2021, https://www.i-scoop.eu/industry-4-0/#:~:text=Industry%204.0%20is%20the%20current,called%20a%20%E2%80%9Csmart%20factory%E2%80%9D.
  3. AMGC, 2021, Advanced Manufacturing a new definition for a new era, viewed 23 February 2021, https://www.amgc.org.au/wp-content/uploads/2018/11/Advanced-Manufacturing-a-new-definition-for-a-new-era.pdf
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A moulded silicone keypad that utilises electrically conductive silicone

Silicone vs Electrically Conductive Silicone

Whether it be designing a new product, or improving an existing piece of equipment, the choice of material is extremely important. It can be overwhelming picking the right material when there are so many options available on the market. We at Jehbco are often asked to help consult our customers on what elastomer is the right choice for their application. 


In this article, we’ll explore the different properties of silicone and electrically conductive silicone (ECS), and what applications each material would be best suited for. Silicone and ECS are both silicone-based products, but ECS is normally impregnated with electrically conductive particles which changes the physical properties of the material. While both elastomers may be used to create similar products, the specific application and environment will ultimately determine whether silicone or ECS will be the better choice for you. The table below summarises some of the key differences between the two materials


Electrically Conductive Silicone Silicone
-60 °C to 170 °C -50 °C to 230 °C
Excellent compression set Excellent compression set
Average weather resistance Excellent weather resistance
Approx. tensile strength 8 MPa Approx. tensile strength 9 MPa
Poor abrasion resistance Poor abrasion resistance
Not compatible with: hydrocarbon fuels, alkalis and acids, steam over 121 °C, halogenated solvents Not compatible with: hydrocarbon fuels, alkalis and acids, steam over 121 °C, trichloroethylene, aromatic hydrocarbons.
Compatible with: oils, brake fluids, hot and cold water, salt water, fire resistant hydraulic fluid, ozone. Compatible with: oils, brake fluids, hot and cold water, salt water, high molecular weight chlorinated hydrocarbons, fire resistant hydraulic fluid, ozone.


It is no surprise that the mechanical properties of silicone and ECS are similar, as they are both silicone-based products. The loading of conductive particles in the ECS material framework is normally not enough to cause any major changes to the fundamental elastic physical properties (tensile strength, compression set, and abrasion resistance) compared to a standard silicone material. However, the conductive particles impregnated within the ECS material provide ECS with a number of different properties that make it very useful for niche applications.


As the name suggests, ECS is electrically conductive, which makes it ideal for use in the electronics industry. ECS can be used a conductor, as well as anti-static and electromagnetic shielding (EMS) applications. This is in stark contrast to standard silicone material, which generally conducts a lot of static and does not provide any EMS capabilities.


Another benefit of ECS is that the conductive particles also increase in the thermal conductivity of the material. ECS can been used in heat exchange components as a heat transfer medium in semiconductor applications. Conversely, standard silicone has good insulative properties and can be used as a heat shield/protective cover for fluid transfer systems.

It is clear to see that there is merit in using either silicone or ECS, depending on the specific application you require and the operational environment.  For help selecting a material consult our applications page and contact us with any questions.

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Grey silicone being mixed in a milling machine

Filler/Extender filled Silicone vs 100% Pure Silicone Rubber

Jehbco silicones specialises in 100% pure silicone rubber. Jehbsil silicone is not adulterated with any cheap fillers or non-reinforcing extenders. In the past, many customers have been unhappy with their existing silicone products as they were highly filled with cheap fillers, resulting in frequently breakage, leaking and in some cases, total product failure. This is particularly true for extremely cheap silicone materials, who can offer a cheaper price by using extenders or fillers to lower their production costs. By purchasing 100% pure Jehbsil silicone products, you can have guaranteed peace of mind that your products will be significantly stronger, more durable and less likely to break than cheaper, low quality products that may contain significant amounts of cost-cutting filler.


Fillers and extenders are bulk materials that can be easily mixed into a silicone matrix. Some fillers with good compatibility with silicone can be loaded to exceptionally high loadings, even up to 60% while retaining some processability. By diluting the silicone with high loadings of cheap non-reinforcing fillers, the overall material cost can be dramatically reduced. The most common filler used in silicone rubber is ground quartz rock. Other extenders include talc, clay and calcium carbonate. These are extremely cheap materials and all of them have a high compatibility with silicone, however high loadings can severely impact the mechanical properties of the final product. Excess filler usually causes a severe reduction in elasticity, tensile strength, elongation to break and tear strength properties.


Table 1: Mechanical properties of 100% Pure Silicone vs Extender Filled Silicone. Extender filled silicone has significantly worse mechanical strength.

100% Pure High Quality Silicone Filler/Extender Loaded Low Quality Silicone
Tensile Strength (MPa) 11.0 6.0
Elongation to Break (%) 460 270
Tear Strength (KN/m) 25 16


This severe worsening of material strength can easily lead to product failure in a variety of situations. Depending on the application, seal, tubing or gasket failure could be catastrophic.


While fillers are mostly used as a cost cutting measure, reinforcing fillers do exist which provide benefits to mechanical properties or impart special properties on the material. A good example is fumed silica, a very high surface area silica form of silica. This material is characteristically present in the base silicone rubber, and can increase the hardness and tensile strength when added in excess (to a point). Other useful fillers include conductive carbon black and silver nanoparticles, which render the silicone electrically conductive and provide shielding from electromagnetic interference. Adding any of these fillers typically increases the total cost of the material, rather than decreasing it as extenders do.


Cheap silicone products are available, but come with the price of reduced strength and durability. By purchasing 100% pure silicone rubber extrusions from Jehbco Silicones you can be assured that your product will last longer and perform better than cheaper, lower quality silicone products on the market.

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