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What is Polyurethane foam
What is Memory Foam


 

 

The Origin of Memory Foam
In the early 1970's, NASA's Ames Research Center funded a development project designed to create a substance
that could help relieve astronauts of the incredible g-forces experienced during lift-off. They believed that one of the
key secrets to reducing g-forces on the body was to use a foam material that could conform to each person's shape
and hold this conformity. While a foam mold of each astronaut's body shape could accomplish this, any movement
would take a person out of this position and create incorrect pressure points against the body. Instead, they created
a new foam material that was visco-elastic and therefore able to conform to a person's shape, but then come back
to a normal shape once pressure was removed from the foam. This could allow an even distribution of pressure or
body weight over the entire surface of the foam, but quickly adapt to any movements of the body.

With this amazing discovery, Fagerdala World Foams of Sweden, one of Europe's largest foam producing companies,
began experiments in the 1980s to perfect it for consumer use. In 1991, the Tempur-Pedic?, a Swedish Mattress
company introduced this material in a mattress form to the people of Sweden with very well-received results. In
1992, Tempur-Pedic? launched the same products in North America and experienced a similar response.
With the success of Tempur-Pedic?, other foam manufacturers in Canada and the United States began to
develop their own visco-elastic memory foam material to offer mattress, upholstering and specialty product
companies the ability to allow consumers to have a variety of options and price levels to choose from.
The differences will be outlined in the following paragraphs and hopefully enable the consumer to make an informed
and savvy decision about which foam mattress product best suits their particular needs.

What Makes Foam have Memory
To give a piece of foam memory, you start with a synthetic polyurethane foam material and add certain types of
chemicals which add an increase in weight or density to the foam. With the addition of these chemicals, a
non-toxic, visco-elastic foam material is created. However, there are many features along the way that will help
determine what type of memory foam you end up with. To understand exactly what differences are found in each
final product, you first have to start with understanding how to grade each foam.

How Foam is Graded
For a material to be Visco-elastic, it will have to be temperature sensitive and have an ability to rebound fairly
quickly and return to its normal shape. Memory foam is graded by its visco-elastic nature and its durability by
breaking it down into the following grading system:
1. Weight (Density in pounds per square foot):
The weight of a foam is determined by the amount of chemicals used in the composition of the polyurethane foam.
The more chemicals, the higher the density and the more visco-elastic it will become. This density will not determine
the hardness of the material, this is done through utilizing the ILD rating structure. Many memory foam mattresses
use a 4 and 5lb. density, but some use as low as 2 and 3lb. densities.
2. ILD Rating (Indentation Load Deflection):
The ILD rating is going to tell you how hard or soft a material is. The 25% ILD rating is the number of pounds required
to achieve a 25% compression of a 4" thick foam using a 50 square inch indentation. An Example of this is as
follows: 20lb. ILD foam indicates that this material took 20 lbs. of pressure to indent this foam 25%. Keep in mind
that the higher the ILD, the firmer the foam.
3. Resilience:
This measures the foam's springiness by determining the percent rebound of a steel ball dropped from a height of 36".
The term "H.R" foam refers to a highly resilient foam that will give a very high "ball rebound" reading. In general, the
higher the resiliency, the better the more durable the foam will be with compression forces.
4. Tensile:
This indicates the extent to which foam can be stretched, measured in pounds per square inch, and how much
elongation in terms of percent of stretch before rupture. This value has little relevance to memory foam mattresses
because they are not usually stretched, and will become compressed only when slept on.
* It is important to remember that these ratings can vary from each foam batch that is poured and that no mattress
company can predict an exact rating on their mattress each time they produce the final product. As an example,
a 10 ILD rated foam could vary from 8 - 12 ILD each time the foam is poured.

What is the initial smell that comes from memory foam?
While the memory foam that comes from the U.S. does not contain toxic ingredients such as formaldehyde or
PBDE (polybrominateddiphenylether), it can have somewhat of a new foam type of smell that can stay for a
couple of days to a couple of weeks, depending on the foam manufacturer. While this smell does not seem
to trigger allergies, it can be a bother initially for people who have sensitivity to smells. If you do experience
this, here are some tips to help the smell go away quicker. Air out the room and wash the sheets after the
first couple of nights sleeping on the mattress. Sometimes a dish of vinegar on the night stand can help
nullify the odors. An ozonator machine will rectify the situation very quickly.

What to look for in a good quality memory foam mattress
Obviously it will be important to allow the foam to do what it is best for: Allowing for a better contouring of your
body shape and therefore less pressure placed on the areas of your body that press harder against the bed.
However, don't just go by your weight, because if you are tall, then your weight is dispersed over the bed more.
A good memory foam mattress will not need a box spring underneath it to make the mattress feel good.
You can order a platform base to increase the height of the bed, but remember that this mattress should feel
good if it was placed on an even, concrete surface. A good way to test the surface of a box spring or box
foundation is to sit or even stand on various areas and see if it compresses underneath you. If you have an
existing foundation that is weak, you can easily place two cut 3/4 to 1 inch thick plywood sheets over it to
give it the necessary support. Also, you may want to look at the warranty that a company offers, because
you can then worry less about spending extra money for a higher weighted mattress and can attempt to
get the correct mattress feel, but save on cost.

Beware of Cheap Imitations!
Unfortunately, not all foam is created equal. Many companies will put together the mattress in the U.S.,
but buy the foam overseas to save money. With overseas foam, we cannot be sure of the quality or the
composition, so we are very wary of recommending mattresses that use memory foam not produced
in the United States, with the exception of Tempur-Pedic, who has the only high quality Swedish
manufacturing facility we know of. The rest of the overseas foam makers produce memory foam that
seems to flatten out with compression, even though it may feel comfortable upon the first feel.
Therefore, the memory foam made overseas may not last as long, be as safe to sleep on, and offer
enough support. Unfortunately, many companies state their beds are made in the U.S. because the
mattress is put together in the U.S., even though they do not use U.S. produced foam. For a list of
companies that have produced documentation verifying that their mattresses are 100% produced in the U.S.,

For a general list of companies and a review of their mattresses.

What is the difference between Tempur-Pedic memory foam and other Memory foam Mattresses?
A Tempur-Pedic mattress classic mattress is eight inches thick and has two layers. The top layer
is composed of three inches of a 5.3 lb. visco-elastic foam that has a listed ILD rating of 14. The
bottom layer of the mattress is composed of 5 inches of 3.5lb., non-visco elastic, High density
polyurethane. It has a cover that is composed of a soft, cotton-like material over a plastic-like
stretchable material. The advantage of the plastic-like material under the cotton material is that
it offers a water proofing for the foam below; the disadvantage would be less breath ability and
more difficulty washing it. You can purchase an additional platform base if you do not already
have a solid enough one.
Other companies are now offering a two layer 4lb.- 6lb. visco-elastic material and some even
offer other types of materials that are layered throughout the mattress. They also offer a wide
variety of ILD ratings, but the most common are 8-20. They are using everything from the thinner
cotton-type cover, to a more bulky wool or quilted cover. While these bulkier covers will feel
softer to the touch, the disadvantages are that they will take away form the memory foam feel
and contouring of the body. Wool covers will be warmer in the winter and hotter in the summer.
The cotton type of covers can wick away moisture, but you may want to get an easily removable
one, so you can wash it every so often. They offer thinner and thicker sizes, but eight inches
usually suffices. If you have a solid platform base already, then it is not necessary to order
one at the time you make your purchase. However, you may need to order one if you loose
integrity in your base down the line.
With all of this said, perhaps the biggest reason many consumers choose to go with a different
mattress company would be price. While Tempur-Pedic? is not the most expensive out there,
there are companies offering memory foam mattresses at significant price reductions.
You can browse through a list of mattress companies who offer Memory Foam Mattresses, mattress pads,

Memory Foam Mattress or Foam Mattress Pad?
Deciding on whether you need a new mattress or mattress pad can be done by realizing what
your current bed can offer you. If your current bed is not so old that it has lost its integrity
and solidity, then a mattress pad may be just the savings that you are looking for.
An old spring mattress can become "lumpy or bumpy" after many years, thereby making any
mattress pad you place over it also "lumpy and bumpy". You also have to worry about the
possibility of sagging which can cause a dip in the middle of the mattress, and thereby
cause a trampoline effect. This trampoline effect takes away from the overall support of your
spine and can lead to back, neck and other types of painful disorders.
If you determine that a foam mattress pad will work for you situation, then the next thing you
will need to do is decide on the same principles that you would need to look at for a memory
foam mattress; softness, density, and thickness.
Depending on your existing mattress, you may want anywhere from a one inch to a four inch
topper, but remember that most standard sheets will not fit over a greater thickness than a
ten inch bed. Two inches can suffice if it has enough of an ILD rating, but if it is too hard,
then it may not offer that extra measure of body contouring that you are looking for.
It is a complicated scenario to find the best topper for your individual situation because
of all the variables, but we have listed sites that you can explore that offer these products

Spring Mattresses Vs. Foam Mattresses
While a spring mattress was the standard for many decades, foam mattresses are
becoming more and more popular due to their unsurpassed comfort and overall body
support. While spring mattresses can feel nice to sit or lay on, they will not offer
anywhere close to the body contouring and therefore spinal support that memory
or latex foam can offer. It will actually cause a trampoline effect and bend inward
when pressure is applied without conforming to the specific bumps and curves
of the body. While foam can shrink over time, springs can bend and lose their
shape over time. Therefore, an old foam bed will likely feel better and offer better
support than an old spring mattress.

Memory Vs. Latex Foam
Latex foam has a higher elasticity or resiliency than memory foam. The result is
that latex will feel more springy and memory foam will feel more solid. Therefore,
Memory foam will not push back up against your body upon pressure being applied
to it. Many mattress companies are using both of these two materials to blend the
perfect mattress combination. Rare allergies to latex can be triggered, but usually
upon skin contact, and not usually not with the natural and synthetic latex mixes l
ike Talay. This is because the proteins thought to trigger these rare allergies are
usually washed away in the Talay latex foam produced in the U.S. Talay latex
is a more supple version of latex. It is more expensive and is composed of synthetic
and natural latex. Because there is no chemicals used in latex composition, it
is the ILD only, that determines the feel of this product.

Foam Vs. Air Mattress
Air mattresses have also become progressively more popular due to the interesting
concept of being able to change the feel of your mattress with a control. With many
air mattresses you can change both sides of the bed to different firmnesses.
Unfortunately, an air mattress will have many parts that can and often do break.
For this reason you will find the fine print of the warranties to contain less coverage.
Also, you will not get the same contouring of the body that you can get with memory
foam, as air beds will not make an imprint of your body. In fact, it is more similar to a
spring bed in that it will cause a trampoline effect and bend inward when pressure is
applied without conforming to the specific bumps and curves of the body. This is
because air displaces to the sides of the body, leaving the middle with less support.
Memory and latex foam are the only substances that can accomplish a contouring
of the body without losing support.

Is Memory Foam Really the Best Support for those Achy Joints?
When you take into consideration the amount of pressure you place on your shoulder
and hips if you are a side sleeper, neck if you are a stomach sleeper or lower back
and sacrum if you are a back sleeper, you will realize that visco-elastic pressure
sensitive foam will offer you the best chance for reducing the overall pressure placed
on your joints by contouring them without pushing back against them. With latex
added to a memory foam mattress it can offer a bit more spring against the concavities
like the small of your back or sides, while not losing the ability to contour and displace pressure points.