Keltan

Keltan. Keltan is a trade name for a family of ethylene propylene diene monomer (EPDM) rubbers produced by Arlanxeo, a joint venture between LANXESS and Saudi Aramco. These synthetic elastomers are renowned for their exceptional resistance to weathering, ozone, and heat, making them critical materials in automotive, construction, and industrial applications. The development of Keltan grades represents significant advancements in catalysis and polymerization technology within the synthetic rubber industry.

Chemical structure and properties

The fundamental chemical structure of Keltan EPDM is a saturated polyethylene backbone with pendent propylene units and a small percentage of a third diene monomer, such as ethylidene norbornene, dicyclopentadiene, or vinyl norbornene. This structure, achieved through sophisticated coordination polymerization processes, results in a polymer with a fully saturated backbone, which confers outstanding stability. Key properties include excellent resistance to ozone cracking, UV radiation, and extreme temperatures ranging from approximately -50°C to over 150°C. It also exhibits good electrical insulation properties, low-temperature flexibility, and resistance to polar fluids like water, steam, and many alkalis and acids.

Production and synthesis

Keltan EPDM is produced primarily using advanced metallocene catalysts and vanadium-based Ziegler-Natta catalysts, which allow for precise control over the polymer's molecular weight distribution, ethylene/propylene ratio, and diene content. The production process typically involves solution polymerization or suspension polymerization in a hydrocarbon solvent like hexane. The Arlanxeo manufacturing facilities, including major sites in Geleen, Netherlands, and Orange, utilize these technologies. Post-polymerization, the rubber is isolated through coagulation and drying processes before being formed into bales or pellets for commercial distribution.

Applications and uses

Keltan's durability makes it indispensable in the automotive industry for seals, hoses, weatherstripping, and braking system components. In construction, it is widely used in roofing membranes, geomembranes, window gaskets, and expansion joints. Other significant applications include cable insulation, conveyor belts, plastic modification as an impact modifier, and various consumer goods like sporting goods and appliance parts. Specialized grades are also employed in medical devices and as a base polymer for thermoplastic vulcanizates (TPVs) used in softer-touch components.

History and development

The development of EPDM rubber traces back to the early 1960s with pioneering work by companies like DuPont and Union Carbide. The Keltan brand itself originated with the Dutch chemical company DSM, which began production in Geleen in the 1970s. A major milestone was DSM's 2008 introduction of Keltan ACE (Advanced Catalysis Elastomers), the first commercial EPDM produced using metallocene catalyst technology, enabling novel polymer architectures. In 2015, DSM's elastomers business was transferred to the joint venture LANXESS-Saudi Aramco partnership, forming Arlanxeo, which now owns and produces the Keltan product line.

Environmental and safety considerations

Keltan EPDM is generally considered inert and non-toxic in its finished, cured state, contributing to its use in potable water seals and roofing over reservoirs. Its longevity and durability reduce material waste over the lifecycle of products. During processing, standard industrial hygiene practices for handling synthetic rubbers apply, including controls for dust and proper ventilation. The material is not readily biodegradable, but recycling initiatives exist, such as reprocessing factory scrap and developing methods for reclaiming EPDM from end-of-life products like tires and roofing materials. Its halogen-free composition makes it a favorable choice from an environmental and fire safety perspective compared to some other elastomers.

Category:Synthetic rubbers Category:Polyolefins Category:Industrial materials