Polyurethane Foam


One of the common ingredients in mattresses and upholstered is polyurethane foam. In descriptions of mattresses, it is often called “poly foam.” With differing densities, resiliency and other characteristics, it can be a base pad, support core, comfort layer, or quilting foam. It was used before the invention of memory foam, which itself was developed from polyurethane.

Polyurethane (PU) foam is made by linking large molecules, usually isocyanates, to each other with modified oil molecules called polyols, usually petroleum-derived. Polyurethane can be solid or foam. The foam is very supportive, making it useful in cushions and mattresses.

Most of the issues with polyurethane foam are related to its manufacture. Isocyanates are toxic before becoming part of the PU foam. I used to work on a line making foam-filled panels for garage doors. Two liquids were injected between the sheet metal skins of the doors. They immediate blended and swelled into foam, which cured to become firm. One of the liquids was an isocyanate, and we had to be extremely cautious around it.

Another issue is outgassing. For some time after it is made, polyurethane releases gasses with an unpleasant odor. Careful selection of ingredients reduces the outgassing and the odor. Outgassing is also reduced if the foam is allowed to air out before being packaged for shipping.

Many mattress manufacturers use “plant-based” polyurethane foam. From 15% to 20% of the polyols in this foam are from plant-derived oils. At the current level of technology, no more plant oils can be used and still have a high quality polyurethane. With further research & development, this may change. The plant-based polyols used are most often from soy oil, but other hydrocarbons, such as coconut oil and palm oil, are sometimes used. Further technological development may see the use of many other plant oils.

One of the major manufacturers of polyurethane foam in the United States is FXI (formerly called Foamex). Foamex was the brand name of the first foam mattresses, made by Firestone. Those were foam rubber (latex), but polyurethane was later used for mattresses. However, much of the polyurethane used in mattresses is made in China.

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This entry was posted on Saturday, June 28th, 2014 at 1:10 PM and is filed under beds, foam, polyurethane . You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

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