ICIS: New blowing-agent rules offer chance to grow
By Al Greenwood, ICIS
Dow Chemical is treating new regulations about blowing agents as an opportunity to grow the company's business, as it seeks to incorporate the new generation of agents into polyurethane systems.
Blowing agents are one of the key components for polyurethane systems. They create the cells that are responsible for the impressive insulating properties of the material.
However, blowing agents are not problem free.
The first two generations, which include chlorofluorocarbons (CFC) and hydrochlorofluorocarbons (HCFC), damaged the ozone layer.
The third generation, which include hydrofluorocarbons (HFC), are ozone friendly, but they are also powerful greenhouse gases. If carbon dioxide (CO2) is given a climate-change score of one, some blowing agents would have scores of 800-1,300.
The US Environmental Protection Agency (EPA) has come up with a list of alternatives to HFCs under its SNAP programme, short for significant new alternatives policy.
These alternatives represent the fourth generation of blowing agents, called hydrofluoroolefins (HFOs).
Replacing blowing agents is not easy because new materials can alter the performance of the polyurethane system. These systems contain several other components in addition to blowing agents, such as isocyanates, polyols, surfactants and additives.
Dow Polyurethane is one of the major polyurethane formulators. It combines these various components into systems, which it then sells to customers. Depending on the system, the end result could be a layer of rigid-foam insulation, a flexible-foam mattress or a moulded piece of polyurethane.
For years, Dow and other formulators have studied how the previous generation of blowing agents interacted with the other components of a polyurethane system, said Chris Chrisafides, North America commercial vice president for Dow Polyurethanes. "If you want better energy efficiency or better density or better demould time for the system, we know which levers to push."
But once one component is changed, it can affect the attributes of the resulting system, sometimes to the detriment of a particular characteristic.
"Fast forward to a new blowing agent that's coming in. These products are very, very different from the incumbent products that are out there," he said.
"All of these attributes that you had a handle on, they are reacting differently. You are getting confounding results when you put these things together," Chrisafides said. "The level of complexity is very, very high."
As an example, a new component could shorten the shelf life of a polyurethane system, Chrisafides said. The components also need to mix well so they do not separate over time. "These are real issues that chemists deal with."
Even if the resulting polyurethane is used in a similar way – such as an insulating foam – the variety of different applications require different formulations.
A refrigerated truck and an ice machine both use insulation. However, the foam for the truck will need to maintain its integrity as the truck undergoes constant agitation from bumpy roads. By contrast, an ice machine is stationary.
For Dow, this is where the opportunity lies. Dow is developing new formulations that can provide customers with the comparable attributes while using the latest generation of blowing agents.
"It gives us a target for innovation at the end of the day," Chrisafides said. "We think this is a great time for the polyurethanes industry. We view this as a positive step."
Already, new products are rolling out that incorporate the latest blowing agents. Dow introduced a new polyurethane integral skin foam, Chrisafides said. These have a foam core with an outer layer incorporated in them. These are often used in the interiors of automobiles as well as office furniture.
Dow said the new integral skin foam keeps the comfort and durability of the previous polyurethane system.
As Dow develops other formulations, it is finding that, in some cases, the foam actually performs better in terms of energy efficiency, he said.
This is important because energy efficiency standards are becoming stricter for buildings.
These account for 41% of all of the energy consumed in the US, Chrisafides said. "That is a number that can be reduced by using materials that are more efficient."
Polyurethane foams are among the best insulators. If the new blowing agents can improve their performance, then it could help companies meet both the new regulations for greenhouse gases and those for energy efficiency.
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