Over the years we’ve been asked a lot of questions – and have always been pleased to share our knowledge with others.
Here is a list of the more commonly asked questions, as well as some of the more quirky or interesting ones we’ve come across – and of course, the answers.
There are a range of natural and synthetic rubbers with different properties, making some more suitable than others for particular applications – the key of course is choosing the most appropriate one! For quick reference you can use the table ‘Industrial Rubber Types Guide at a Glance’. For specific requirements, please ask our rubber products specialists for guidance.
The two key ratios are Coefficient of Friction and Coefficient of Thermal Expansion. The first (friction) indicates the force needed to move an elastomer over a given surface versus the total forces pressing on the elastomers and surface. The latter (thermal expansion) shows the ratio of the original length versus the change in length as a result of temperature variation.
Quite simply, a metal ball of a particular size and weight is dropped from a given height onto an elastomer sample. The rebound resilience figure is an indication of how much the ball actually bounced.
Rolls of Rubber Sheeting should be stored in accordance with the “Guidelines for storage – Rubber products” as detailed in the Specification BS ISO 2230-2002. This International Standard gives guidelines for the inspection; recording procedures; packaging and storage of products, assemblies and components made from vulcanised or thermoplastic rubber prior to being put into circulation.
It is applicable to both solid and cellular rubber products made from natural and synthetic materials. This is a most useful standard and we would recommend its use to all customers who store rubber based products.
At J-Flex we have invested in automated laser sensing equipment that performs in line measurements of the specified thickness for calendered sheet rubber products. As a result we confidently provide thin and tight tolerance products to our clients worldwide. For specific requirements please ask our rubber products specialists for guidance.
Fluoroelastomers are fluorinated synthetic polymers designed for harsh environments including aggressive chemical and temperature applications. These materials are sometimes referred to as Viton™, which is a registered trademark of DuPont Performance Elastomers.
J-Flex is an official Chemours Viton™ licensee. Other suppliers of Fluoroelastomer polymer are Dyneon; Solvay and Daikin.
Fluoroelastomer compounds are based on polymer that takes advantage of the high strength of the fluorine to carbon bond and the high ratio of fluorine to hydrogen. This unique chemistry and proper compounding means that some fluoroelastomer materials can perform continuously in temperatures of 204°C and 300°C intermittently.
The ASTM D2000 designation for fluoroelastomers is HK meaning the highest heat resistance and the lowest swell available of rubber type elastomers.
There is a crude but useful method that can be used for identifying different polymers simply by burning on a direct flame. We would urge caution with this method and ensure that all tests are carried out in a well ventilated area away from hazardous goods.
Our tests and observations were conducted by taking samples of sheet and extruded products and results are shown in a table Polymer Identification by Flame Test.