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Polyurethane foam is the most common upholstery material used today. It is found in almost all mattresses, sofas, the seats in your car, spray foam insulation and more. This material is a petrochemical product. The main chemical ingredient is TDI (Toluene diisocyanate). This chemical makes up approximately two thirds of the weight of the finished foam.
The other one third of the finished weight is created from Polyols. This is a form of alcohol, which is almost always made entirely from petrochemicals. There are now some polyols containing plant based alcohols (soy, castor bean, tea tree, aloe, et cetera), in very small percentages. These foams are often labelled as natural, which we feel is entirely misleading as the vast majority of the finished product is not natural.
The other critical part of making all polyurethane foam is a blowing agent. This is a chemical in the form of a gas which is blown into the mixture to turn it into foam, essentially aerating the mix. Different types of polyurethane and memory foams simply use different blowing agents. Some foams are water expanded, which is another clever way of suggesting that somehow the foam is natural. This is simply green washing.
Simply stated, memory foam is polyurethane foam. Essentially, there are different formulas involved in the mixture, and different blowing agents in the foaming process. Memory foam may also be called viscoelastic foam.
Memory foam is desirable as it is more durable than traditional polyurethane foam and also offers moderately improved pressure relief and support. The enhanced durability is not because of the "memory" and is actually a result of the density of the material. Typical polyurethane foam used in mattresses is 0.8 to 1.8 lbs ft3 while most memory foam is 3.0 to 7.0 lbs ft3.
The "memory" in memory foam is actually due to the higher elasticity of memory foam versus traditional polyurethane foam. Both varieties of foam will try to return to their original shape. Memory foam and polyurethane foam do break down over time. The only difference is that memory foam typically takes longer to break down.
Zedbed Canadian Memory Foams
Tempur material is found exclusively in Tempur-Pedic branded products and is essentially the original memory foam. Tempur is a proprietary formula, not found in any other mattress brand. Tempur material for the North American market is manufactured in Albuquerque, NM and Duffield, VA.
Zedbed is a Canadian soy-based memory foam, manufactured via a proprietary process in Shawinigan, QC. There are only two mattress companies in all of North America who actually make their own foam, and we're proud to say we offer both (Zedbed & Tempur-Pedic). Every other mattress company buys generic foam from third party sources and then simply markets the foam to suit their sales goals.
To simplify, the denser we make polyurethane or memory foam, the more durable it will be. The challenge with regular polyurethane foam is that as we increase the density, it becomes more brittle. As the density increases so too does the firmness, which creates the unfortunate side effect of the foam no longer being comfortable. This is the primary reason why most higher density polyurethane foams are of the memory foam variety. Memory foam is more apt to have additional flexibility and forgiveness as the density increases.
Whether intentional or not, many mattress salespersons will wrongfully inform their customers that mattresses are not treated with chemical flame retardants. This is simply untrue. As all forms of polyurethane foam are made up of hydrocarbons, they are exceptionally flammable. Thus, chemical additives are required to ensure the foam is less combustible. The challenge is that there is very little regulation of which chemicals may or may not be used, and the foam maker is not obligated to disclose these ingredients.
Formaldehyde is the most common chemical flame retardant used in mattresses containing polyurethane or memory foam. This is because formaldehyde is abundant and very inexpensive. Less common today than it was even just 5 years ago PBDE's (polybrominated diphenyl ethers) can also be used as fire retardants in polyurethane foam; PBDE's are less common now than formaldehyde based fire retardants as they are known to bio-accumulate in breast milk, blood and fat tissues. This is a major concern as PBDE's can effect the brain and nervous system while in developmental years, as well as disrupting the thyroid and estrogen hormonal balance in humans. Mattress manufacturers are not legally obligated to disclose which fire retardant chemicals are used.
If you have concerns about chemical flame retardants we suggest reading the law tag on the mattress. Even though there are no specific requirements for listing the chemicals inside the mattress, there is fortunately a law requiring the finished components to be listed on the tag. Thus, all we need to look for is "polyurethane foam." If this material is listed on the law tag, the mattress has been treated with chemical flame retardants.
The only mattresses available today which are not treated with chemical flame retardants are certified organic mattresses with proper credentials to back up these claims.
Moisture will speed up the degradation of all polyurethane foams. It is important to keep moisture out of this material and to ensure the area around the material may breathe and have adequate air circulation. In the case of caring for your mattress, using natural materials such as sheep's wool is very important.
There are two categories of "natural memory foam"
One variety of natural memory foam is actually a slow-response latex foam aggressively marketed as "natural." This slow responding latex foam contains additional chemical additives needed to inhibit the slower, "memory foam" type of responsiveness. This material does contain some natural content; however it still contains styrene and butadiene. These two chemicals are both volatile organic compounds (VOC's) and as such we feel it is inappropriate to market this foam as "natural memory foam." One must simply read the ingredients list to verify these two VOC's are present in this "natural memory foam."
On July 25, 2013 the Federal Trade Commission in the United States barred three different companies from advertising mattresses as free from VOC's. View the report here.
Some polyurethane foams incorporate plant alcohol in the chemical mixture. These sources can be soy beans, caster beans, tea tree, aloe and many others. As we touched on earlier, it is important to remember that these polyols can only be a very small percentage of the finished product. Although marketed as natural, we feel this is inappropriate. The Mattress & Sleep Company simply labels these foams as "Plant-based foam" to denote that in the products we offer with this material, a portion of the polyol has been supplanted by a plant-based alcohol.
When in doubt, always ask for the Eco Institut certification. Eco Institut is a well respected German organization which has the ability to test samples of foam for VOC's, including styrene and butadiene. If either of these compounds are contained in the foam sample, even in trace amounts, the foam sample will simply fail the test and will not receive certification. Green Sleep and Sleeptek/Obasan have obtained full Eco Institut certification.
Yes. All varieties of polyurethane foam (including memory foam) produce an odour. All plant-based polyurethane foams (soy, castor bean, tea tree, aloe, etc) produce an odour, regardless of product claims. This is commonly referred to as "off-gassing." The odour will dissipate with time. As each person is different, sensitivity to off-gassing will vary. There are also many chemicals used in polyurethane foam that have absolutely no odour, or no noticeable odour when the concentration in the air becomes low enough, which explains why the really noticeable odours dissipate with time. In truth the actual chemical off-gassing will never go away completely. If you are concerned about off-gassing, natural rubber tree latex foam is an alternative which does not contain harmful chemicals.
Note: Although natural rubber tree latex foam does not off-gas, rubber does still have an odour. This odour is not offensive for the overwhelming majority of our clients and is almost never noticeable unless you are inspecting the rubber without coverings.
The key consideration for those with chemical sensitivities is to avoid products which gas-off certain harmful chemicals.
Yes. Polyurethane foam (including memory foam) is primarily a closed-cell foam. This means that neighbouring cells are walled off from each other, which does not allow airflow. Although certain memory foams claim to be open-cell, once weight is applied to this foam, the cells collapse and are no longer able to breathe.
This lack of airflow causes polyurethane foam to retain a great deal of heat. When a mattress is hot, the sleeper will perspire more, disrupting deep sleep. Only a small number of polyurethane foam mattresses incorporate wool or other breathable natural fibres, and most of the time, these natural fibres are 5-10% of the overall blend, with the rest being polyester.
The Mattress & Sleep Company offers a variety of bedding products designed to help alleviate temperature concerns with memory foam mattresses. It is common to add natural fibres to a foam mattress to improve airflow.