Material Futures - Part 2




The Way Ahead - New technology development  

The S- Curve

All new products, including window frame materials, follow an S-curve for return on the cost of development.

When compared with an existing technology, initial developments in a new technology are costly for little real improvement in operating performance. The initial performance may even be less than that of the existing technology in some important respects. As times passes the new technology enters a region where the improvements achieved are very cost-effective and the performance overtakes that of the existing technology. At the end of the cycle the cost of development increases for small improvements actually achieved and a newer technology is developed.

Many of the new window frame materials are at the lower end of the S-curve and, given the right conditions, are ready to experience the rapid growth section.

The market ecology

Superiority to existing technology is not the only requirement for a successful new product or technology. Superior products will fail if they do not establish themselves in the market ecology. Markets resemble complex ecosystems and if the product niche is already occupied then it is very difficult for a new product to establish itself and survive. The new product must compete with existing products and also displace them before it can become successful. It must achieve both the critical mass and also the route to market. Many companies realise that their existing technology investments could be rendered redundant by the new technology and there is resistance to the technology. If the everlasting light bulb were to be invented then would a light bulb company want to develop it? (This is a bit misleading since as of June 2000 there will be no incandescent light bulb manufacturers in the UK, still the concept applies). New materials will face more than technical barriers because better mousetraps do not always take the market by storm.

Despite this, new materials are the key to new technology. The companies that are fastest in the development of the new materials may well decide the future of the window industry (but I would say that - being a Materials Engineer by training).

The new issues

Whatever the new materials are there are new issues for window frame materials that will affect the whole market. The new materials may well be able to use these issues to gain crucial market advantages over the existing materials.

Environmental impact

Increasing pressures from environmental groups is starting to have an effect in the market. Life Cycle Analyses of window materials have concluded that there is no basis for recommending any particular frame material on environmental impact grounds. The environmental impact for products varies as much from factory to factory as it does from material to material and the production level impact for various materials is much smaller than the impact of the product over it’s lifetime. Despite this, environmental concerns will grow in importance and both existing and new materials will need to reduce their environmental impact in the future. Ignore the environment at your peril! New materials based on recycled products will reduce the environmental impact at the production level as well as establish good “green credentials”.

Thermal efficiency

A window is an “appliance” that uses energy and generates CO2 as a result. A new and important issue will be the thermal efficiency of the complete window and the way the material and design of the window affects this. Windows are often only seen as an energy loss to a building but correctly designed windows can minimise this and can actually add energy to the building. The new concept of “window energy rating” will make it possible to directly compare the thermal efficiency of the complete window unit for various materials and manufacturers (details at New materials may use energy efficiency as a method of outflanking the existing materials.

The ideal window material

In order to assess the new materials it is necessary to first define what the requirements of the ideal material are. This ideal material meets the requirements of:

§         Low and stable raw material cost.

§         High flexural modulus to provide stiffness without reinforcement.

§         Low thermal conductivity to provide energy efficiency.

§         High resistance to corrosion and fungus.

§         Easy to colour and match other architectural features.

§         Easy to work with and manufacture (as well as low Health and Safety risks).

§         High fire resistance.

§         Low environmental impact.

This is illustrated in the diagram below:

Existing frame materials can meet many of these requirements but the market is not static and the right new material could change the market as dramatically as PVC-U did in the 1980’s.

The new materials

The development costs and simple polymer chemistry make it unlikely that any new bulk polymer will be developed and used for window frames. Equally, the application of new metals to window frames is unlikely and there are no obvious candidates that have not already been used for frame manufacture.

The areas to watch are those where polymer alloys and compounds of existing plastics are developed to modify and extend properties and to lower the cost. Iron was an “old” material in the 19th century but the development of steel making extended the applications enormously. In a similar manner existing plastics can be alloyed, compounded and filled to extend the properties and lower the cost. The new composites will use either low cost fillers to marginally stiffen and fill the matrix or high cost reinforcements to greatly stiffen and reinforce the matrix. Typical examples are pultrusions, thermoplastic pultrusions, ABS/ASA composites, recycled materials (PVC or PE) with cellulose extenders (wood flour, flax or other natural fibres) and other forms of PVC.

These new materials will sometimes defy the categories that we are used to. Is a material with 60% wood and 40% plastic a wood or a plastic? Will the timber window industry see resurgence whilst the PVC-U industry fights a rear-guard battle? Interesting times ahead.

The Material Futures series is designed to look at some of the possible materials that could be used for window frames in the future. The series is:

Part 1: Material Futures - The Way Behind

Part 2: Material Futures - The Way Ahead (This article)

Part 3: Material Futures - The New Composites (1)

Part 4: Material Futures - The New Composites (2)


Last edited: 11/03/10

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