Development of high-performance elastomers as a substitute for fluoropolymers

Sustainable solutions for sealing technology

Users of poly- and perfluorinated alkyl substances (PFAS), also known as ‘forever chemicals’, are under considerable pressure due to the restriction proposal of the European Chemicals Agency (ECHA). This is one reason why many companies are looking for sustainable alternatives, especially for technical applications that have to withstand extreme conditions.

While fluorine-free substitutes are already available for various everyday applications, there is an urgent need for innovative solutions in specialised sections. In particular, sealing technology requires high thermal and chemical resistance, which so far can only be guaranteed by fluoroelastomers. One example of the many applications where high-quality and reliable seals are required is in hydrogen applications or vacuum systems for the production of photovoltaic modules. Without these seals, the progress of the energy transition could be significantly affected.

To meet this urgent need, the PREPARE initiative is developing fluorine-free coated elastomers that offer customisable modular solutions. This actively contributes to the creation of sustainable and high-performance materials that meet the requirements of the future.

Fluorine-free elastomers for the highest performance requirements

The ‘HATE-Fluor’ project is developing customized, fluorine-free coated elastomers that meet the dynamic requirements of the market.

This innovative approach comprises three key strategies:

• increasing the thermal and thermo-oxidative stability of the elastomers using novel antioxidants
• developing optimized formulations for maximum durability
• implementing a state-of-the-art coating system that effectively protects the elastomer from oxidative attack and chemical decomposition

Customized solutions for a wide range of industries

The modular technology is aimed at a variety of industries, including raw material manufacturers, manufacturers of semi-finished and finished products, as well as users in sections such as Mechanical Engineering Industry, Medical Engineering, Clean Room and Semiconductor Technology, Chemical Process Engineering, as well as Electrical and Electronic Applications. The flexibility and adaptability of the solutions make it possible to meet specific requirements and provide individual solutions for complex challenges in each industry.

Subproject 1: Development of high-performance elastomers

The first subproject focuses on the development of high-performance elastomer compounds as sustainable alternatives to fluoropolymers in technical applications. The aim is to significantly improve the thermal and thermo-oxidative stability of fluorine-free elastomer substrates with innovative, novel antioxidants. The focus here is set on highly effective stabilisers based on phosphorus-containing diphenylamines that promise outstanding performance.

To this end, tailored formulations of the elastomer substrate are being developed at Fraunhofer LBF that not only ensure maximum durability but also optimal adhesion for the subsequent surface treatment. This process involves the targeted selection of the base polymer, the crosslinking system and low-migration oligomeric plasticizers to create high-performance and durable materials.

Subproject 2: Coating of elastomers

The second subproject is dedicated to the development of advanced coating solutions for elastomers. The focus is on coating systems modified with 2D materials based on high-performance polymers. The permeation of water vapour and oxygen is to be reduced by up to 99% through the targeted modification of layered silicates. These systems are already being used successfully in the section of protective coatings for electronic components. The focus of this research project is on the first-time use of such paints on elastomer materials.

In order to achieve ideal adhesion of the paint to the elastomer substrate, appropriate low-pressure plasma processes are developed. These make it possible to optimize the surface of the paint in a targeted manner using plasma polymers. Depending on the application, the sliding properties and the feel of the surface, for example, can be adjusted. In addition, additional functionalities such as an easy-to-clean surface can be integrated to reduce contamination during product storage. This results in a coating kit for the applied design of the overall elastomer product.