Traditionally, polystyrene and polyurethane have been used to provide the insulation for SIPS panels. However, it is increasingly being recognised that these materials might not be the most environmentally friendly materials that can be used in this modern application.
One company that has tackled this problem head on is IFS Chemicals Ltd, a company that has developed a unique process using a recycled, renewable source of vegetable oil as the raw material ingredient.
Envirofoam Sustain TM is a cost-effective, low-density polymer foam, which is produced in the same manner as conventional polyurethane foams. The two-part resin and isocyanate composition can be manufactured using conventional low and high-pressure dispensing equipment. However, the resin component used in the manufacture of Envirofoam Sustain contains a polyol known as Enviropol R201. This polyol is derived from a renewable and recycled source and is therefore quite unlike anything else on the international chemical market.
Enviropol R201 is derived from a recycled oil, designated LF100, which is supplied to IFS to a tight technical specification. LF100 is refined from oil collected largely from large-scale processes where it has been used in industrial frying processes. This fact is important in terms of carbon footprint. The oil has already fulfilled its usefulness prior to being used again in the manufacture of a bio-polyol.
IFS Chemicals converts the oil to a biopolyol using a technique developed over 20 years ago. The process has been continually refined, resulting in a process which is highly efficient and which requires very little energy in the conversion process. In fact, the energy requirement has been estimated at about 10% of that used in more conventional polyol processes. Another key factor of this new technology relates to the blowing agent. The chemical composition of Envirofoam Sustain allows the use of particularly attractive blowing agents in the foaming process. Many conventional blowing agent gases have a detrimental effect in terms of greenhouse gas emissions (as denoted by their Global Warming Potential, GWP). The blowing agents used in Envirofoam Sustain have a GWP of ‘less than 1’, something that has led to a very wide interest in this product.
The mechanical, adhesive and thermal properties of Envirofoam Sustain are somewhat similar to those of conventional grades of foam insulation. However, Envirofoam Sustain has a particularly low lambda value (0.022-0.023 W/mK) giving rise to low U-values in buildings and low energy ratings in domestic and commercial appliances. Furthermore, Envirofoam Sustain has obtained approval under the U.S. BioPreferred program. Consequently, the liquid resin can be labelled as a certified product, the only polyurethane chemical to receive this accolade. To date, there is no European version of the scheme, but governments are currently considering the introduction of a similar program. There is a growing recognition that many commercial/industrial products could contain significant levels of bio-based materials.
In terms of processing attributes, the only noticeable difference between Envirofoam Sustain and conventional polyurethanes is that Sustain grades exhibit improved foam flowability. This leads to improved foam distribution and a more consistent density distribution. Envirofoam grades of polyurethane have been used by the insulation industry for more than 15 years. These products have been based on Natural Oil Polyols using a process perfected by IFS Chemicals in the 1990s. Envirofoam Sustain is based on that same proven technology but utilizes recycled vegetable oil as the starting derivative. Whilst Envirofoam Sustain has been used extensively for the manufacture of hot water storage cylinders, supermarket display cabinets and commercial refrigerators, its use in SIPs panels is a relatively recent, but very successful development. Quite apart from its use with traditional OSB facings, Envirofoam Sustain has been used with cement particle board to produce a SIP structure with improved fire performance for wall applications. The BBA-approved panels, which are manufactured by MIB International of Cardiff, are used to construct loadbearing walls in buildings up to 10 metres (or three storeys) high.
They are also suitable for laterally loaded infill panels spanning up to 3.1 metres vertically between restraints in multi-storey buildings. Examples of successful installations are student accommodation at Belfast University, Aston Hall nursing home and the Hilton Hampton Hotel in Wales. Following the completion of a hospital in Liverpool, it was stated that the panels “have produced a cost saving of 25% for Balfour Beatty when compared with the use of brick and blockwork, on top of the thousands of pounds worth of savings on preliminaries achieved through reduction in time”.
For further information please telephone 01485 601155 or visit www.ifs-group.com/s38/ENVIROFOAM-SUSTAIN.html
