Articles posted by Jehbco Silicones

Jehbco Silicones manufactures extrusions which are made from 100% pure silicone elastomer and exhibits the characteristics of both inorganic and organic materials, which offers a number of advantages not found in other organic rubbers, such as [1][2];

a) Excellent resistance to heat and cold

Silicone rubbers have a broad operating temperature of -50°C to around +250°C for addition (e.g. platinum) cured and around +300°C for peroxide cured. Furthermore, it exhibits only slight changes in physical properties between -50°C to +180°C.

In terms of heat resistance, silicone rubbers can be used indefinitely at 150°C with virtually no change in its properties and can be used for 10,000 hours of more at 200°C.

Table 1 Operating life and temperature of silicone rubbers before any changes in properties.

Whereas in terms of cold resistance, the embrittlement point of silicone rubbers is -60° to -70°C, as opposed to typical organic rubbers which is between -20° and -30°C.

Table 2 Cold resistance comparison between organic rubbers and silicone rubbers.

b) Higher longevity in hostile environment.

On top of its excellent thermal resistance, silicone rubbers also have exceptional weatherability. It can be exposed to wind, rain and UV rays for extended periods of time with almost no change in its physical properties. Hence, it has higher longevity in hostile environment compared to organic rubbers. Furthermore, when phenyl groups are added to the polymer molecules, silicone rubbers are able to resist radiation and can be used in the manufacturing of cables and connectors used in nuclear power plants.

c) Good flame retardancy

Flame retardancy and/or self-extinguishing properties can be added to silicone rubbers by adding a small amount of flame retardant. When they do burn, unlike organic polymer rubbers, silicone rubbers do not produce black smoke or noxious gas. Hence, silicone rubbers are suitable to be used in consumer electronics and business equipment that are used in closed spaces such as aircraft and subways.

d) High purity

Silicone rubber is exceptionally pure compared to other elastomers. Furthermore, it is physiologically inert, which consequently affects living tissues to a lesser degree than by exposure to other organic polymers. Hence, it is suitable for use in the food and medical industry. Additionally, to ensure that our products are safe for sensitive applications, some of Jehbco’s products have certifications such as FDA CFR 21 177.2600 for food contact, AS/NZS 4020 for drinking water and USP Class VI for biological tests.

Due to its many advantages, silicone rubber is used in nearly every industry to improve the quality and function of various products and manufacturing processes.

For further information about the benefits of Jehbco’s silicone products and how it could suit your specific application, please contact us.

References

1. Shin-Etsu Chemical Co. Ltd., ‘Characteristic Properties of Silicone Rubber Compounds’. Shin-Etsu Chemical Co. Ltd., August 2016.
2. Wacker Chemie AG, ‘Solid and Liquid Silicone Rubber: Material and Processing Guidelines’. Wacker Chemie AG, n.d.

Jehbco Silicones provides a wide range of tubing products:

• Internal diameters can start from 0.5 mm
• Outside diameters can go up to 60 mm
• Different hardnesses (durometers) are available
• Different colours are available

Figure 1: Different sizes of transparent silicone tubing

Jehbco’s tubing is primarily used for fluid transfer:

• Water transfer for boiling and chilled appliances
• Fluid transfer in medical application
• Fluid transfer in batteries or engines specific to the automotive or energy industries
• Fluid transfer in precision scientific equipment for science industry (ie. laboratories)

Our tubing for water and medical applications are made of platinum rubber. These products are thoroughly post cured to further decrease levels of extractables. The process is integral so our tubing is compliant with the AS/NZS 4020 standard. Jehbco has currently tested and complies with the AS/NZS 4020 standard for platinum 70 rubber for the following colours: transparent, red-transparent, blue-transparent and black transparent.

AS/NZS 4020 is a standard that is designed to test any products for use in contact with drinking water¹. These products include tubing, pipes or any material used for applications in plumbing and water supply. The standard ensures that drinking water in contact with such products meet water quality values which are nationally recommended.

The standard provides methods of testing and compliance limits for the effect of a product/material².  For the different tests of the standard, products are immersed in water or exposed to substances. Each test has specific procedures and are specific to the type of product2. The different methods of testing are described below²:

Taste of water: “A trained panel tastes water extracts to determine whether products release any compounds that impart discernible taste”ⁱⁱ

Appearance of water: Colour or turbidity of the water extract is measured.

Ability of a product to support the growth of aquatic micro-organisms: Dissolved oxygen levels are monitored during 8 weeks to examine the ability of the product to support bacterial growth.

Cytotoxic activity of water extract: Water extract is placed in contact with mammalian cell lines. Any adverse effect on the cell health is considered as evidence of a cytotoxic effect.

Mutagenic activity of water extract: An AMES test is used. Specific bacteria are mixed with the water extract. Any change in the bacteria’s genetic nature is considered as evidence of mutagenic activity

Extraction of metals: Levels of arsenic, antimony, barium, cadmium, chromium, copper, lead, mercury, molybdenum, nickel, selenium and silver in the water extract are analysed and compared to the limits of the National Health and Medical Research Council (NHMRC) guidelines.

High-Temperature tests: Products in contact with hot water are tested at high temperaturesⁱⁱ.

Products are required to comply with all the tests relevant for that product type to be certified by AS/NZS 4020 standard. Jehbco’s tubing is regularly tested as the test reports for the AS/NZS 4020 test are valid for 5 years³.

To learn more about our silicone tubing, see our tubing page or contact us.

References

1. Australian/New Zealand Standard, “AZ/NZS 4020 Standard` in SAI global limited website, viewed on 25th June 2019, https://www.saiglobal.com/PDFTemp/Previews/OSH/as/as4000/4000/4020-2005.pdf
2. AWQC, “Overview of the Standard” in AWQC website. Viewed on 25th June 2019, https://www.awqc.com.au/our-services/product-testing/overview-of-the-standard
3. Eurofins, “AS/NZS 4020 Test for Watermark™ Certification” in Eurofins website, viewed on 25th June 2019, https://www.eurofins.com.au/biopharma-services/testing-solutions/chemistry-toxicology/asnzs-4020-test-for-watermark-certification/

From food processing to petrochemicals,  silicone seals and gaskets find a multitude of applications. The key factor in understanding what makes silicone preferable over other materials is its Compression Set Resistance.

Compression set resistance is the ability of rubber to return to its original thickness after prolonged compressive stresses at a given temperature and deflection¹.

Compression set results for a material are expressed as a percentage of the maximum figure. A compression set of 100% says that the elastomer never recovers from its compressed state. The lower the percentage figure, the better the material resists permanent deformation under a given deflection and temperature range. A low value means that the tested rubber has a good capacity to keep its sealing properties and will have a better chance of effecting a seal in a given working environment for a longer period².

The sealing application could be either static or dynamic with combinations of contact-types i.e. non-metal to metal, or metal to metal. To ensure the right seal, the shape of the seal must be retained over the time period it is designed for in every case³. The property that directly corresponds to shape retention is compression set. We help our customers identify the right silicone with the right compression set for their application.

You can find the compression set values in our Certificate of Conformance, which we provide on request.

An example of the technical specification we provide as part of the Certificate of conformance.

After the rubber selection, choosing the correct extrusion profile is the next step in the design process. Customers can provide their own extrusion designs and samples or provide us with the details of the application for us to create a new design from scratch.

Jehbco specialises in manufacturing gaskets and o-rings. Ultimately, it is the manufacture of gaskets to the right dimension and strength that makes the seal work and fulfil its purpose. Our gasket manufacturing quality assurance comprises comprehensive steps right from generating drawings with dimensional tolerances to sequential step by step inspection of cut lengths, cut quality, jig preparation and joint strength.

O-ring test rig

2.2mm dia sponge cord gaskets

 

The testing phase usually involves us sending samples and the customer testing them at their facility. We also have in-house testing facilities to check the joint strength and coefficient of friction. We have a dedicated O-ring test rig on which we could carry-out leak tests and compression tests.  We can develop O-rings made of silicone rubber and sponge to match our customer’s requirement based on their sealing data. Please refer to our O-ring design article here.

To match our products with your application, please see our applications page and contact us if you have any silicone queries.

References

1.  Laurence W. McKeen, in The Effect of Creep and Other Time Related Factors on Plastics and Elastomers (Third Edition), 2015
2.  Andrew Onions, Compression Set of Elastomeric Materials & Recognising the Risks, MacLellan Rubber 19 January 2015.
3.  Gillier R, Lefrancois M, Ritter T, Static Sealing – Concept & Technologies, Technetic Group.

 

Jehbco Silicones provides silicone solutions to a wide variety of industries, ranging from construction, to food and beverages. For many projects, our customers are happy with a standard colour such as white, but we understand that some projects have strict aesthetic requirements, and as such require a little more attention.

Description: A small sample of the colours we can produce at Jehbco Manufacturing

For example, blue is the standard colour for seals in the food and beverage industry, as the high contrast of colours can alert production staff if the seal is damaged and contaminates the food product. Our silicone seals are perfect for this application as not only are we able to make practically any of our existing or new profiles in blue, but they are also 100% food-grade.

Another example of where we would use our custom colour matching services would be for the architectural industry. We know that any design-focused industry such as architecture places a strong emphasis on the aesthetics of the final project. As such, we always work with our customers to develop the perfect custom solution in terms of design and appearance. Whether it be matching the colour of our silicone expansion joints to your panelling, or implementing the perfect colour combination using our window glazing seals, Jehbco will be able to deliver.

Beyond the more obvious examples above, some of our customers purchase a wide range of products from us and colour code each individual item to help differentiate similar products, or to prevent confusion when receipting in goods. One customer of ours purchases a range of different sized silicone tubes, and requests that every different sized tube is a different colour. In the past, our customer told us that the wrong sized tubing would often be installed by their production team due to the different sizes being so hard to tell apart. After switching over to our custom-coloured tubing, the number of defects due to incorrect tubing sizes almost dropped down to zero!

It is clear to see the benefits of using Jehbco’s custom colour matching services, the possibilities are only limited by your imagination. At Jehbco, we only produce 100% pure silicone products for your guaranteed peace of mind. If you have an idea that might require a custom colour, or want to manufacture a custom solution that you can be confident with, feel free to consult our applications page and contact us with any questions.

Jehbco Silicones is an industry leader, manufacturing high quality silicone extrusions in Australia. Whilst silicone and Styrene Butadiene (SBR) share some similarities in their characteristics and chemical resistance levels, their physical properties vary, which depending on the conditions of application, a justified material selection can be made.

Silicone and SBR can both withstand temperatures as low as approximately -40° C, making them both considerable for low temperature applications. However, silicone rubber offers a significantly higher heat resistance making it an ideal material for high temperature applications.

Very similar to natural rubber, SBR has an excellent abrasion resistance which make an ideal material choice for dynamical applications involving a large amount of physical demand. This is not the case with silicone, which with its low abrasion resistance is much better suited for high-temperature static applications. The tensile strength of SBR is much higher at 18 MPa which also make it an ideal candidate for applications with high dynamical loading and force.

Both materials exhibit the same degree of compression set allowing both materials being acceptable for applications that demand high durability.

In general, silicone is an ideal material for static and high-temperature applications whereas SBR is a common elastomer for applications requiring a high resistance to dynamical load and friction. The ideal material for your application highly depends on your requirements. To help guide you in choosing the right material for your application, please contact us.