Project: Development of functionalized polyurethane gels for electrotechnical application

This project is directed to the development of novel nanomaterials reinforced and functionalized polyurethane gels. It is anticipated to develop these gels from a mixture of polyether alcohols of different molecular weight of which one is produced by depolymerization of polyurethane flexible foams by a novel process to contain a portion of nanostructured oligoureas. The mixture of polyether alcohols is further formulated with inorganic nanostructured materials and special oils to combine characteristics of these materials so as to increase electrical properties of the gels. The formulated materials are finally reacted with a mixture of di and triisocyanates prepared by partial trimerization of a mixture of aliphatic and aromatic diisocyanates. By this way of formulating the polyurethane gels will receive the desired properties and structures such as a high insulation efficiency characterized by high throughput voltages of >20 kV, of high surface resistance, and low flammability. Such material has not been created until now so that gels of any kind are presently not available for the medium voltage range. _x000D_Gels in electrical applications are prepared COly from silicone resins and cover a voltage range up to 5 kV. Polyurethane gels have until now not been used in such processes but as sealants for cable connectors as rigid casts in the same voltage range. Otherwise, polyurethane gels are produced in medical applications, e. g. in decubitus treatment, or in sports assemblies or equipment such as saddles or upholstery. These polyurethane gels are produced by standard processes from two typical polyether alcohols and standard biuret triisocyanates but with low stoichiometric isocyanate indexes of 50 or less so that several unreacted groups reCO which lead in turn to low electrical values. First lab experiments with such combination of materials showed a pronounced increase in the electrical values so that industrial application seems to have a sound basis._x000D_The technical fields of application are in electrical industry where is a search for such materials to be used as insulating stuffs in cable connectors or issues in walls to be filled or as insulating gels inside mantled cables used in ship building or mining. Furthermore, such gels are considered to be of use in assemblies of rescue or emergency transport or in leisure time apparatuses where dynamic flexibility is a necessity. Another application is the use of such polyurethane gels made tixotropic as coatings in fast moving machinery. _x000D_The markets of such gels are COly in the electrical industry, sports assembly industry, and medical technology. In this project only the field of electrical application is considered and the market investigated. According to the present state (12/07) the market for medium voltage applications of gels is in the range of about 1000 t per year in Europe. Considering the fast growing markets in Asia and the distribution network available by the Ps there an additional market of about 2000 t per annum is anticipated. In this investigation the market in the USA, South America or Australia was not covered. _x000D_The consortium is headed by GT Elektrotechnische Produkte GmbH of Germany, a company with long experience in the field of electrical equipment and cable connectors. The consortium Ps are SC ELMET CONSTRUCT SRL . of Romania, a producer of electrical equipment and of electrical systems and installations, EUROPUR s.r.o. of Slovakia, a producer and developer of elastic polyurethanes and systems, and B. T. & C. of France, a supplier of electrical equipment and of installation systems. The University of Kassel, Germany, should plan and perform any electrical tests and give support in the materials development. University of Applied Sciences at Wildau, Germany has experience in materials development with special emphasis on polyurethane specialties.

Acronym ELTGEL (Reference Number: 4227)
Duration 01/08/2008 - 31/03/2011
Project Topic By incorporation of nanostructured particulate matter and insulating additives to polyurethanes prepared from polyether mixtures and special triisocyanates new polyurethane gels will be developed to meet the characteristics of insulation materials for use in cable connectors or wall issues at >15kV
Project Results
(after finalisation)
The aim of the project was to develop a new type of polyurethane gel for electrical application and its use in electrical modules. This aim was achieved by the gels formulated and produced on a small scale as well as the modules being filled with them. The outstanding properties of the gels with very flame retardancy (measured by LOI >55) and high breakthrough voltage (>150 kV/mm) show that the originally estimated aims were by far more than fulfilled and the modules produced showed as well outstanding properties in the tests performed in lab and in the field. Furthermore, the gels are easily produced from standard raw materials at rather low costs, are easily metered into the cavities of the modules and allow for a fast production cycle.
Network Eurostars
Call Eurostars Cut-Off 1

Project partner

Number Name Role Country
6 University of Kassel Partner Germany
6 B. T. & C. Produits Électrotechniques S.A.R.L. Partner France
6 Technische Fachhochschule Wildau (University of Applied Sciences) Partner Germany
6 EUROPUR s. r. o. Partner Slovakia
6 GT Elektrotechnische Produkte GmbH Coordinator Germany