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.