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Memory foam |
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NASA's
Ames Research Center funded a project that helped to develop
and design a substance that could help astronauts in relieving
the huge g-forces that are experienced during lift off. This
project was kicked off in the early 1970's. The Research
Center believed that the substance that was one of the key
secrets to reducing the g-forces on the body was a foam material
that would conform to the shape of the body of each astronaut.
A foam mold could have worked on each astronaut's body
and their shape; any movement would create incorrect pressure
points against the body. Creating a new foam material that
was made of visco-elastic that conformed to the body, but
would come back to normal shape once the pressure was removed
from the foam. This then allowed even distribution of pressure
or body weight over the entire surface of the foam. This foam
then quickly adapts to any movements from the body.
This amazing discovery by Fagerdala World Foams of Sweden
created major experiment to perfect this foam for consumer
use. Fagerdala is one of Europe's largest foam producing
companies.
The Tempur-Pedic ®, a Swedish Mattress company introduced
this material in a mattress form in 1991. The people of Sweden
received the results well. In 1992, Tempur-Pedic ® launched
the same products in North America and experienced a similar
response.
The success of Tempur-Pedic ® made other foam manufacturers
in Canada and the United States begin to develop their own
visco-elastic memory foam material. They offered mattresses,
upholstering and specialty product companies the ability to
allow consumers to have a variety of options and price levels
to choose from.
The differences are outlined in the following paragraphs.
This will hopefully enable the consumer to make an informed
and savvy decision about which foam mattress product best
suits each of their particular needs.
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How does foam
have a memory |
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When giving a piece of foam a memory,
you must start with a synthetic polyurethane foam material.
Adding certain types of chemicals which add an increase in weight
or density to the foam, and the addition of non-toxic chemical
a visco-elastic foam material is created. There are many features
along the way that will help determine what type of memory foam
you end up with. Learning how to grade each foam will help you
to understand exactly what differences are found in each final
product. |
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Grading each foam |
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For a material to be Visco-elastic,
it will have to be temperature sensitive as well as have an
ability to rebound fairly quickly and return to its normal shape.
Memory foam is graded by its visco-elastic nature. Its durability
comes by breaking it down into the following grading system:
• 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.
• 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.
• 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.
• 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.
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What is the initial
smell that comes from memory foam? |
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While the memory foam does not contain
toxic ingredients such as formaldehyde or PBDE (polybrominateddiphenylether),
there can be a new foam type of smell. This can stay for a couple
of days up to a couple of weeks. This depends 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.
For those of you do experience this there are some tips to help
the smell to dissipate quicker. Airing out the room and washing
the sheets after the first couple of nights sleeping will help
to eliminate the odors. Another tip may be to use a dish of
vinegar on the night stand can help nullify the odors. |
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The good qualities
of a memory foam mattress |
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It is important to allow the foam
to do its job. 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. Don't go by just your
weight, because if you are tall, then your weight is dispersed
over the bed more than if you are short.
If you have 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. |
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Spring mattresses
Vs. foam mattresses |
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A spring mattress was the standard
for many many years but now foam mattresses are becoming more
and more popular due to their unsurpassed comfort and overall
body support. Spring mattresses may feel nice to sit or lay
on it 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. The foam can shrink over time but, springs
can bend and lose their shape over time. Therefore, an old foam
bed will likely feel better and offer better support much longer
than an old spring mattress. |
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Foam mattresses
Vs. air mattresses |
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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. |
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Memory foam Vs.
Latex foam |
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Latex foam has a higher elasticity
or resiliency than memory foam. With this resilience the result
of the latex will feel springier and memory foam will feel more
solid. Therefore, memory foam will not push back up against
your body upon pressure being applied to it. 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 with the natural and synthetic latex
mixes like 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 suppler version of
latex. It is more expensive and is composed of synthetic and
natural latex. There are no chemicals used in latex composition,
it is the ILD only, that determines the feel of this product. |
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Memory foam really
is the best support for those achy joints |
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Taking 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.
This is done by contouring them without pushing back against
them. The latex added to a memory foam mattress can offer a
bit more spring against the concavities like the small of your
back or sides. While doing this you will not lose the ability
to contour and displace pressure points. |
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