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Freudenberg Follows High Safety Standards and Develops DOTG-free Elastomers Products

Published on 2011-03-31. Author : SpecialChem

Freudenberg Sealing and Vibration Control Technology have been following a strict strategy of replacing hazardous substances with harmless alternatives which goes far beyond legal requirements. In 2009 a particularly problematic hazardous plasticiser, until then indispensible in vibration technology applications with high damping forces and limited ageing, was successfully replaced with harmless alternatives. In order to eliminate this "problem compound" from 48 rubber mixtures in 128 different applications, an alternative solution had to be found for each individual mixture, without any compromises concerning material characteristics. This was achieved after 5 years of development activity and was only possible with cross-departmental co-operation between material and product developers, raw material managers, manufacturers and customers.

non hazardous substances

REACH (registration, evaluation, authorisation and restriction of chemical substances), the new European community regulation on chemicals, aims to achieve the same on a legislative level, improving the protecting of human health and environment from possible risks related to the handling of chemicals. Freudenberg, world-wide leading developer, manufacturer and processor of rubber and elastomer products, uses a huge variety of basic materials and additives, e.g. reinforcing fillers, plasticisers, anti-ageing agents, cross linking agents, vulcanisation chemicals and others. According to REACH it is necessary to register and approve all chemicals to ensure safe and environmentally friendly products.

Freudenberg puts great efforts both into the control of the chemicals and raw materials used as well as into the exchange of data with all raw material suppliers in order to identify possible risks posed by individual substances and in order to be able to comply with customer requirements regarding the safety and environmental compatibility of products. A Freudenberg-internal process called 'FSS 7' aims to avoid particularly hazardous substances and provides purchasers and users of Freudenberg products with the highest possible protection. In this context Freudenberg focuses particularly on substances with chronic hazard potential (suspected substances) even when they have not been classified as such by law. Material developers in all European countries are thereby applying the precautionary principle in order to find alternatives to be able to offer safe and environmentally friendly products. Examples for this are the handling of so-called polycyclic aromatic hydrocarbons and the vulcanisation accelerator DOTG.

PAK in technical elastomer products

In the past, polycyclic aromatic hydrocarbons (PAHs) were found in many every day products with plasticisers based on mineral oil. PAHs in such products are particularly relevant due to their frequent contact with skin. Freudenberg is committed to eliminating the use of such PAH-containing plasticisers.

However, PAHs occur in the production process also in small amounts in carbon black which is indispensable in the rubber industry as reinforcing filler in order to achieve particular elastomer material properties. The PAHs are attached to the carbon surface and are, in addition to that, surrounded by an elastomer matrix. Freudenberg has carried out extensive internal research and has concluded that there is no significant migration of carbon black PAH to the elastomer surface. The PAH exposure does therefore not pose a risk and is far below the legal limit requiring declaration.

In terms of PAHs for technical products it can be said that PAH-containing plasticisers or rubbers are not used in any of the Freudenberg products;
  • various types of carbon black which are used as reinforcing fillers in order to achieve specific product characteristics do not pose a health risk;
  • Freudenberg's material developers have also developed rubber materials which use virtually PAH-free types of carbon black for use in special applications (e.g. food industry, medical technology).

Innovative vulcanisation accelerator is the solution

Certain high-temperature-acrylate and ethylene-acrylate rubber compounds (HT-ACM and AEM) are processed using the vulcanisation accelerator DOTG (N,N'-Di-orthotoluylguanidin). Studies carried out by the trade association have shown that in certain thermal processes such as vulcanisation or tempering the degradation product o-toluidine is formed. In animal experiments this substance has shown to be carcinogenic and is therefore classed as carcinogenic to animals under dangerous substances legislation. Although no legal restriction has so far been imposed on the use of DOTG, Freudenberg is developing DOTG-free elastomers products. Alternative cross-linking chemicals make it possible to achieve nearly identical characteristics in the final product. Freudenberg's target is the complete substitution of DOTG. By doing so, Freudenberg lives up to its promise to provide innovative products which offer high safety standards and optimal protection for the health of employees, processors and customers.

A current example is the new DOTG-free high-temperature ACM material HT ACM 380. This strictly safe and environmentally friendly material which does not release any problematic substances, and the sealing products made from it, fulfil not only legal requirements but also all of the customer specific demands, for example, from the power tools sector or automotive industry. Freudenberg as a premium producer of elastomers seals, moulded parts and diaphragms takes on a leading role in the development and design of products and is committed to providing safe and clean materials.

About Freudenberg

Being wherever the customer is is a matter of course for Freudenberg Dichtungs- und Schwingungstechnik. Close, long-term partnerships with NOK, Japan, and Freudenberg-NOK General Partnership, USA, ensure that we are able to meet our customers' demands in every location around the world. In Europe, Freudenberg Dichtungs- und Schwingungstechnik has a dense network of production plants and sales offices stretching from Newcastle (England) in the West to Moscow (Russia) in the East, and from Tampere (Finland) in the North to Athens (Greece) in the South.

Source: Freudenberg

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