INSIGHT: PU players deliver energy efficiency

09 May 2012 17:23  [Source: ICIS news]

By Heidi Finch

PU foams help reduce the weight of vehiclesLONDON (ICIS)--Improving energy efficiency is a huge driver for the polyurethane (PU) business, producers stressed at the UTECH conference in Maastricht, the Netherlands, in April.

The key automotive, furniture and appliance sectors are all looking for lower cost and more technically efficient products. A stricter legislative regime is also prompting further PU product development.

Take the automotive sector. The EU has imposed tougher carbon dioxide emission limits of 130 grams per kilometre (g/km) on all new cars registered in 2012. The longer-term target is to cut average emissions to 95g/km by 2020.

PU producers are looking to help manufacturers reduce weight and, therefore, fuel consumption in vehicles by modifying their own product formulations.

Bayer MaterialScience (BMS), for instance, says that the weight of finished PU automotive parts can be cut by up to 30% using a combination of fillers that replace the usual mineral fibres in the finished product.

“With a density of just 0.9 kilograms per litre, the material is even lighter than water,” the company says.

BMS’s lightweight PU solution also ensures that “the excellent mechanical properties required in the automotive sector remains intact,” says Birgit Meyer zu Berstenhorst, the developer of the material.

Reduced fuel consumption is a draw for consumers. High oil prices have fed through to much higher fuel costs and gasoline prices in Europe are among the highest globally.

Gasoline premium unleaded spot prices were assessed in the high $900s/tonne (€690s/tonne) FOB (free on board) AR (Amsterdam, Rotterdam)  in January 2012. They continued to trend upwards during the early part of the first quarter and spiked at the end of March at $1,226/tonne FOB AR, according to ICIS price history, although they have dropped since then.

A PU-spray skin foam from BASF can also help reduce weight in automotive parts and therefore fuel consumption. PU can also be used for instrument and interior door panelling and has visual and touch benefits, according to the company.

Lightweight composite structures made of PU foams combined with thermoplastic films are also used in the engine, roof and front grilles of some vehicles. According to BASF they have excellent mechanical properties, high rigidity and temperature stability.

There is also momentum in the PU sector to boost energy efficiency in the appliance sector for the benefit of end-consumers and to comply with tighter legislative requirements.

An example of this includes BMS’s initiative to reduce the cell pore size of PU foam by 40%, which lowers thermal conductivity and improves the insulation performance of the foam by 10%, without compromising product properties.

Dow Chemical’s patented pascal insulation system provides another way of improving energy efficiency in the appliance sector. The insulation process involves a two component system, combining a specially-formulated PU foam with a patented vacuum process, which has been developed by Italy’s Cannon SpA.

The system is claimed to be more time-efficient, consistent and effective at cavity filling without using any more material. Most importantly, the new process and insulating system can boost energy performance in household appliances by up to 10% compared with current PU insulating systems, according to Dow Chemical.

BASF also has an approximately 100% PU content refrigerator, known as “the coolpure 1.0 concept refrigerator”, in contrast to the 70% PU content in standard refrigerator models.

Refrigerators are usually built from an outer steel shell, with a polystyrene inner layer. PU foam is the insulating component. In the coolpure 1.0 concept fridge, PU foam is used in both the inner and outer layers of the fridge as a “permaskin.”

The coolpure 1.0 concept refrigerator was showcased at UTECH to show OEMs (original equipment manufacturers) what is possible with PU in appliances, Friedhelm Lehrich, who is Vice President, European Business Management for the BASF foams businesses, said.

According to the company, the new refrigerator ensures optimised insulation through the innovative usage of PU foam as an adhesive. This means that vacuum insulated panels (VIPs) can be attached to the inner walls of the refrigerator or freezer doors and not simply to level surfaces – a limitation with conventional construction methods.

“By having the flexibility to stick the VIPS to the inner wall of the door, the energy efficiency of the appliance can be increased by up to 4%,” said Nils Mohmeyer, of BASF Construction and Appliances.

The open-celled rigid foam can also be used as the core material for the VIPs. It has better processability and is easier to recycle compared with standard materials, added Mohmeyer. Commonly used core materials in VIPs are precipitated silica and nanogel.

On top of more energy-efficient PU products, there are also more efficient production methods. Examples of these include the use of TDI (toluene diisocyanate) high resilience (HR) foams in bedding and furniture applications rather than higher density MDI (methyl diphenyl diisocyanate) based foam.

The TDI HR foams can be produced using various technologies such as BMS’s ‘Poly Harnstoff Dispersion’ process or PCC’s Rokopol iPol technology, among others.

While producing a wide range of foams with Rokopol iPol technology for example, foam manufacturers also achieve high material efficiency through superior block shape and thin skins” according to Kevin Pickin, Business Development Manager at Germany-owned PCC Rokita.

This material efficiency and waste reduction clearly brings environmental benefits whilse minimising costs.

The main driver in the downstream foam industry is to ensure “high comfort and durability at the lowest density so, as foam is sold by weight, provided product quality is not compromised there is a corresponding economic benefit,” says Pickin.

Given its energy and cost-saving potential, PU is set to have a promising future in various end-sectors with wider and potentially more exciting application possibilities. PU as an adhesive, used in combination with carbon or glass fibres and epoxy resin, or PU as a foam to reinforce thinner steel plates, are just some examples of PU being developed to replace metals in structural parts of cars.

The drive to reduce weight is particularly important for electric vehicles, where the additional weight of the battery needs to be offset by other lighter  parts, said a BASF company source. PU’s application versatility has been explored more in the automotive than the appliance sector, but as BASF’s coolpure concept fridge shows, there is more development potential.

While headway has already been made in reducing cell size to improve energy efficiency, as seen by BMS, the next stage could be to reduce cell size in the PU foam to a nano scale to take energy efficiency to a whole new level, says Lehrich from BASF.

$1 = €0.77

By: Heidi Finch
+44 20 8652 3214

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