Note: Descriptions are shown in the official language in which they were submitted.
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SUPPORT APPARATUS WITH GEL LAYER
FIELD OF THE INVENTION
The present invention is generally directed to apparatuses designed for bodily
support. In particular, the invention is directed to apparatuses that provide
an
improved level of comfort, particularly pressure relief, as well as improved
control of
heat transfer.
BACKGROUND
Multiple apparatuses are known in the art for providing support to the body of
a user.
Such apparatuses generally comprise one or more layers of padding or
cushioning to
provide functional support of the user's body and to provide such support
while also
providing a level of comfort. Similarly, such apparatuses may also comprise
1s mechanical supports, such as coil springs.
Advances in the art are generally directed to apparatuses that provide the
functional
support necessary in such apparatuses but also provide increased comfort or
provide
a decrease in the volume of materials necessary to provide the support. For
2o example, United States Patent No. 6,701,556 to Romano et al. discloses
mattress or
cushion structures designed to improve pressure distribution while reducing
the
overall thickness of the mattress or cushion. Further, U.S. Patent No.
6,804,848 to
Rose discloses an air support sleep system having an upper mattress air
posturizing
module and an adjustable air posturizing sleep surface.
While the apparatuses commonly used for bodily support may provide functional
support, they yet fail to provide a level of comfort useful for facilitating
restfulness or
sleep, or for providing a greatest relief of pressure for the body parts in
contact with
the support surface. Gel materials are generally known to provide good
physical
comfort and pressure relief. Further, gels are also known to exhibit a
relatively high
thermal conductivity. Accordingly, gels, such as polyurethane gels, are
generally
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regarded as having a"cooP' feel to the body, as body heat is perceptibly moved
away
from the body when in contact with the gel.
Accordingly, there still remains a need in the field for apparatuses useful
for bodily
support that provide functional support to the body of the user, as well as
providing
comfort and, possibly, therapeutic benefit. Such properties, as well as
further
desirable and beneficial properties, are met by the present invention.
SUMMARY OF THE INVENTION
The present invention provides an apparatus for supporting at least a portion
of the
body thereon. Beneficially, the apparatus comprises a gel layer comprising a
gel
having a measurable hardness in a specified range. In further embodiments, the
apparatus comprises a plurality of layers, and preferentially, the layers
comprise at
least two different types of materials, one layer of the apparatus comprising
a gel.
The apparatus of the invention is beneficial for improving pressure mapping
and
providing pressure relief, and it also provides the ability to absorb and
transport heat
according to various parameters, such heat capacity being adjustable depending
upon the composition of the apparatus, particular the composition of the gel
layer of
the apparatus.
In one embodiment of the invention, the apparatus comprises a gel layer
overlying
one or more additional support layers. According to this embodiment of the
invention, the gel layer comprises a gel having specific physical properties
identified
as providing increased support pressure and relief to a user, and also
providing a
user with an increased perception of comfort (i.e., a good "feeP'). The gel
layer can
be the outermost layer of the apparatus, therefore being in direct contact
with the
user. According to further embodiments, the apparatus can also comprise a
covering
overlying the gel layer. Preferably, the covering layer is not of structure or
thickness
to substantially reduce or mask the comfort and support provided by the gel
layer.
Non-limiting examples of coverings encompassed by the invention include a
textile
layer, a film layer, a coating layer, and a foam layer.
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The gel used in the gel layer of the apparatus is particularly formulated to
exhibit
physical properties, such as hardness and elasticity, that are within a range
that not
only provide a good "feel", or increased comfort, to a user but also provide
increased
support and pressure relief beneficial to the user. In one particular
embodiment, the
gel used in the gel layer has a measurable hardness in the range of about 0.5
kPa to
about 50 kPa. In another embodiment, the elasticity of the gel is measurable
in
terms of hysteresis, the hysteresis percentage of the gel being in the range
of about
15% to about 80%.
io The one or more additional support layers used in the apparatus can include
any
type of support material generally known in the art of bodily support
apparatuses,
particularly in the art of mattresses and seating apparatuses. For example,
the one
or more additional support layers may include one or more of the following: a
foam
layer; a spring layer; a textile layer; a gas layer, a wood layer, a metal
layer, and a
plastic layer. Accordingly, the apparatus of the invention finds use in a wide
variety
of supports. For example, the apparatus of the invention could be used for
supporting the entire body or only a portion of the body. As such, the
inventive
apparatus finds use in home settings, such as bedding or seating, in office
settings,
such as chair seats, chair back rests, chair arm rests, keyboard wrist rests,
and the
like, in transportation, such as car seats or other interior components,
medical
settings, such as bedding, wheelchairs, and clothing, particularly footwear,
as well as
other settings wherein comfort or pressure relief are to be maximized. In one
particular embodiment, the apparatus is a mattress. Non-limiting examples of
further
support apparatuses encompassed by the invention include seating apparatuses,
pillows, mattress toppers, footwear cushions (or insoles), arm pads, and wrist
pads.
According to another embodiment, the gel layer, in addition to the gel, may
further
comprise a content of one or more fillers. Such fillers are particularly
useful in
modifying the thermal conductivity of the gel used in the gel layer. As
previously
noted, gels are typically by a "cool" feel, in part arising from the thermal
conductivity
of the gel in that it transports heat away from a warmer object in contact
with the gel,
such as the body of a user. The fillers used in the gel layer are
preferentially capable
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of reducing the thermal conductivity of the gel, thereby allowing the gel to
exhibit a
feel to a user that is less "cool".
Various types of filler can be used according to the invention. The filler
material
should generally be non-reactive with the gel, or with possible derivatives of
the gel
or the precursors thereof (e.g., isocyanates and polyols in the case of
polyurethane
gels). Preferably, the filler is a material capable of beneficially affecting
one or more
physical characteristics of the gel including, but not limited to, the thermal
conductivity of the gel. In one particular embodiment of the invention, the
filler
io material is selected from the group consisting of cork pieces, cork flour,
wood pieces,
wood chips, foam flakes, textile fibers, textile pieces, paraffins, hollow
spheres,
synthetic microspheres, mineral particles, glass beads, gasses, active agents,
nanoparticles, and mixtures thereof.
is In one particular embodiment, there is provided an apparatus for supporting
at least a
portion of the body thereon, the apparatus comprising afiIled gel layer
overlying one
or more additional support layers. Preferentially, the filled gel layer has a
thermal
conductivity of less than about 0.20 W m-' K-'
20 In another aspect of the invention, there is specifically provided a
mattress. In one
embodiment, the mattress comprises a gel layer overlying a foam layer.
Preferably,
the gel layer comprises a gel having a hardness in the range of about 0.5 kPa
to
about 50 kPa. In a preferred embodiment, the gel is a polyurethane gel.
According
to further embodiments, the mattress can comprise further support layers, such
as a
25 spring layer, and can also further comprise a covering, such as a textile
layer.
In another embodiment, the mattress comprises a gel layer overlying a spring
layer.
Preferably, the gel layer comprises a gel having a hardness in the range of
about 0.5
kPa to about 50 kPa. In a specific embodiment, the gel is a polyurethane gel.
3o According to further embodiments, the mattress can comprise further support
layers,
such as a foam layer, and can also further comprise a covering, such as a
textile
layer.
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The mattress according to this aspect of the invention can be further
characterized by
additional physical properties of the gel used in the gel layer. For example,
in one
embodiment, the gel layer comprises a gel having an elasticity such that the
hysteresis of the gel is in the range of about 15% to about 80%.
In still another aspect of the invention, there is specifically provided a
mattress
topper. In one embodiment, the mattress topper comprises a gel layer overlying
a
foam layer, wherein the foam layer preferably is of a thickness that is
substantially
less than an average thickness of a standard mattress. In one particular
io embodiment, the foam layer of the mattress topper has a thickness of less
than about
5 cm. In further embodiments, the mattress topper can comprise a covering
overlying the gel layer. Preferably, the gel layer comprises a gel having a
hardness
in the range of about 0.5 kPa to about 50 kPa. In a preferred embodiment, the
gel is
a polyurethane gel.
In yet another aspect of the invention, there is specifically provided a
pillow. In one
embodiment, the pillow comprises a gel layer overlying a foam layer. In one
preferred embodiment, the gel layer overlies only a portion of the foam layer.
Preferably, the gel layer comprises a gel having a hardness in the range of
about 0.5
2o kPa to about 50 kPa. In a preferred embodiment, the gel is a polyurethane
gel. In
still further embodiments, the pillow can comprise a covering overlying the
gel layer.
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described more fully hereinafter in connection
with
preferred embodiments of the invention which are given so that the present
disclosure will be thorough and complete and will fully convey the scope of
the
invention to those skilled in the art. However, it is to be understood that
this invention
may be embodied in many different forms and should not be construed as being
limited to the specific embodiments described herein. Although specific terms
are
used in the following description, these terms are merely for purposes of
illustration
and are not intended to define or limit the scope of the invention. Like
numbers refer
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to like elements throughout. As used in this specification and the claims, the
singular
forms "a," "an," and "the" include plural referents unless the context clearly
dictates
otherwise.
s The present invention provides an apparatus useful for bodily support,
particularly
support that, in addition to being functional, also provides increased comfort
and
pressure point relief for a user. The apparatus is characterized by its use of
a gel
material exhibiting preferred physical characteristics for providing a
pleasing "feel" to
a user, as well as therapeutic benefits.
The gel used in the apparatus of the invention can comprise any gel that is
stable,
non-toxic, and generally known to provide a cushioning effect while
maintaining a
degree of structural stability and support. In particular, the gel can
comprise any gel
material having a hardness and elasticity that are within a preferred range,
as more
fully described herein.
Polyurethane gels are particularly useful according to the invention. Further,
other
gels that are resistant to hardening over time, have limited expandability,
and are
resistant to substance degradation (e.g., from migration of volatile agents,
such as
plasticizers) could also be useful as the gel in the present invention.
Preferably, the
gels used in the apparatus of the invention are also shock absorbent and
resistant to
vibration.
Polyurethanes are generally understood to be the product of the chemical
reaction
between a polyisocyanate compound and a polyfunctional alcohol (i.e., a
polyol).
One example of a general reaction scheme for preparing a polyurethane compound
is shown below:
0 0
1( H H 11
0=C=N-R,-N=C=0 + HO-R2-OH --> i -N-RI-N-C-O-R2-Oz
O"
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wherein R, and R2 can be various organic groups including, but not limited to,
straight or branched chain or cyclic alkyl, alkenyl, or alkynyl groups, as
well as
various aryl groups. Of course, the above scheme is provided only as an
example of
the preparation of the polyurethane compounds useful according to the
invention and
is not intended to be limiting thereof. Additional examples of polyurethane
gels
capable of use according to the invention are disclosed in United States
Patent No.
6,191,216, United States Published Patent Application No. 2004/0058163
(Application Serial No. 10/618,558) and United States Published Patent
Application
No. 2004/0102573 (Application Serial No. 10/656,778), which are incorporated
herein
lo by reference. Examples of other types of gels useful according to the
invention are
disclosed in United States Patent No. 4,404,296, United States Patent No.
4,456,642, and United States Published Patent Application No. 2005/0186436
(Application Serial No. 11/058,339), which are incorporated herein by
reference.
In one embodiment of the invention, the gel used in the gel layer of the
apparatus
comprises a polyurethane gel. Particularly, the polyurethane gel is may be
prepared
using raw materials having an isocyanate functionality and a functionality of
the
polyol component, wherein the product of the functionalities of polyol and
isocyanate
is at least 5.2, but preferably at least 6.5 or 7.5. In preferred embodiments
of the
present invention, the polyol component for producing the gel includes a
mixture of
one or more first polyols having hydroxyl numbers below 112, and one or more
second polyols having hydroxyl numbers in the range 112 to 600, wherein the
weight
ratio of the first polyols to the second polyols lies between 90:10 and 10:90,
the
isocyanate characteristic of the reaction mixture lies in the range from 15 to
59.81,
and the product of isocyanate functionality and functionality of the polyol
component
is at least 6.15.
In a further specific exemplary embodiment, the raw materials for producing a
gel
useful according to the invention includes one or more polyisocyates, and a
polyol
component consisting of a first component of one or more polyols having
hydroxyl
numbers below 112, and a second component of one or more polyols having
hydroxyl numbers in the range 112 to 600, and optionaliy a catalyst for the
reaction
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between isocyanate and hydroxyl groups, and optional fillers and/or additives
which
are known from polyurethane chemistry, wherein the weight ratio of first
component
to the second component lies between 90:10 and 10:90, the isocyanate
characteristic
of the reaction mixture lies in the range from 15 to 59.81, and the product of
isocyanate functionality of the polyol component is at least 6.15.
The polyol component for producing the gel preferably consists of one or more
polyols having a molecular weight between 1,000 and 12,000 and an OH number
between 20 and 112, wherein the product of the functionalities of the
polyurethane-
lo forming components is at least 5.2, and the isocyanate characteristic lies
between 15
and 60.
As isocyanates for gel production, those of the formula Q(NCO)n may preferably
be
used, wherein n represents 2 to 4 and Q denotes an aliphatic hydrocarbon
radical
having 6 to 18 C atoms, a cycloaliphatic hydrocarbon radical having 4 to 15 C
atoms,
or an aromatic hydrocarbon radical having 8 to 15 C atoms. The isocyanates may
be
used in pure form or in the form of the conventional isocyanate modifications,
such
as urethanisation, allophantisation or biuretisation.
2o Gels, such as polyurethane gels, are particularly useful in the apparatuses
according
to the invention due in part to the balanced pressure distribution provided by
the gel.
Unlike standard padding materials, which react to an applied pressure, such as
a
user sitting or lying of the padding, by deforming along only the axis of the
applied
pressure (i.e., the axis perpendicular to the plane of the padding), gels tend
to exhibit
tri-dimensional deformation properties. In other words, the gel reacts to the
applied
pressure by deforming along three axes: the X and Y axes in the plane of the
gel
surface, as well as the Z axis that lies perpendicular to the plane of the gel
surface.
This leads to an even distribution of the exerted pressure, which lessens the
pressure felt by the user at the pressure points. This is preferable over the
standard
padding materials, which allow for an uncomfortable, and possibly damaging,
accumulation of pressure at the pressure points. Accordingly, in addition to
providing
added comfort, the gel provides health advantages, such as increased blood
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circulation, encouragement of correct posture, and alleviation of pressure
concentration, which can lead to serious conditions, such as bed sores, or
other
types of ulcerations.
Gel materials useful in the apparatus of the invention are particularly
beneficial for
their ability to maximize pressure distribution, which can be seen through
pressure
mapping. Pressure mapping is a clinical tool that measures interface pressure
that
occurs between a user and a support surface, such as a seat or a bed surface.
With
standard support cushions and paddings, pressure maps tend to reveal localized
io high pressure areas, which indicate an inability to evenly distribute
pressure. Gels,
especially polyurethane gels, and other gels useful according to the
invention, are
superior to standard supports because of their ability to distribute pressure
away from
pressure points, as demonstrated by pressure maps showing lower pressure
readings at the pressure points.
Gels used according to the present invention are characterized by the specific
physical properties they exhibit. Two physical properties that particularly
characterize
the gels of the invention are hardness and elasticity. Optimization of these
two
properties exhibited by the gels allows for preparation of an apparatus
providing both
objective and subjective comfort and support. In other words, gels according
to the
invention having a certain degree of hardness and a certain degree of
elasticity
provide therapeutic benefits (i.e., objective comfort), as previously
described, but also
provide a user with a good "feel" (i.e., subjective comfort). The ability to
provide both
objective and subjective comfort is particularly useful because a support
apparatus
designed to provide therapeutic benefit to a user may not always feel good to
the
user. Conversely, what feels good to a user may not always provide therapeutic
benefit to the user. However, gels according to the invention having a
hardness and
elasticity within the presently specified ranges provide both objective and
subjective
comfort.
The gel used in the gel layer of the inventive apparatus is characterized by
having a
low degree of hardness, such hardness being measurable as the force deflection
of
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the gel at a specific compression. Gel hardness can be measured according to
any
known method, and a gel useful according to the invention can be identified as
having a hardness in a specified range. One method particularly useful
according to
the invention for measuring gel hardness is the testing method ISO 3386-1, as
s designated by the International Organization for Standardization (ISO).
According to ISO 3386-1, a method is provided for the calculation of the
compression
stress value of various materials. The compression stress/strain
characteristic is a
measure of the load-bearing properties of the material, and the testing method
1o provides two formulas for calculating the compression force deflection in
kilopascals
(kPa), which provides a measured hardness of the material.
Specifically, under the ISO 3386-1 standard, a gel according to the invention
can be
measured for a hardness determination through a compression load deflection
test.
15 In particular, a 5 cm x 5 cm x 2.5 cm gel sample is subjected to a
compressive force,
with a 70% maximum compression, and gel hardness is measured as the stress
applied to the gel (in kPa) at 40% compression.
A gel useful according to the invention has a low measurable hardness.
20 Preferentially, the gel has a measurable hardness that is less than 90 kPa,
more
preferably less than 80 kPa, still more preferably less than 70 kPa, and most
preferably less than 60 kPa. In one embodiment, the gel used in the invention
has a
measurable hardness in the range of about 0.5 kPa to about 50 kPa. According
to
further embodiments, the gel has a hardness in the range of about I kPa to
about 40
2s kPa, about 1.5 kPa to about 30 kPa, or about 2 kPa to about 25 kPa.
According to another embodiment of the invention, the gel used in the gel
layer of the
apparatus is characterized by having a measurable elasticity that is within a
specified
range. In solid mechanics, a material is understood to behave elastically if
it changes
30 shape due to an applied load, and when the load is removed, the material
recovers
its original shape. The elasticity of a material is inversely proportional to
its stiffness.
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One method for evaluating the elasticity of a gel for use according to the
invention is
through determination of the hysteresis exhibited by the gel. Hysteresis is a
property
of systems (usually physical systems) that do not instantly follow the forces
applied to
them, but react slowly, or do not return completely to their original state.
Hysteresis,
then, can, be evaluated as the ability of a material, such as a gel, to return
to its
original shape after removal of a force on the gel.
In one method for determining hysteresis, a force is applied to a gel, which
leads to
compression of the gel. The deflection of the force by the gel at 70%
compression is
io measured, and the external force is removed, allowing the gel to
decompress. The
deflection of the gel under no compression (i.e., after removal of the force)
is then
measured. The hysteresis of the gel (evaluated as a percentage) is the
difference
between the two force values at the defined deflections. Accordingly, a gel
exhibiting
a low hysteresis percentage would be expected to be highly elastic, in other
words,
have a rapid and significantly complete return to its original shape. A gel
exhibiting a
high hysteresis percentage would be expected to be less elastic, in other
words have
a more delayed and less complete return to its original shape.
According to the present invention, it is beneficial for a gel for use in the
gel layer to
2o be elastic, but not exhibit physical properties that are highly temperature
dependant.
For example, viscoelastic foams, commonly known as "memory foam", typically
exhibit a glass transition temperature (Tg) at around room temperature. In a
cold
environment, a memory foam product will tend to be harder and less resilient.
Conversely, in a warmer environment, a memory foam product will tend to be
softer
and more resilient. Accordingly, the product changes in response to the
surrounding
temperature, including temperature changes attributable to body heat flow.
Gels useful according to the present invention, being highly elastic, do not
suffer from
such a drawback. Rather, the gel the gels exhibit an elasticity (or percentage
3o hysteresis) that is not temperature dependent. In one embodiment, the gel
used in
the invention has a measurable hysteresis in the range of about 15% to about
80%.
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According to further embodiments, the gel has a hysteresis in the range of
about
20% to about 70%, about 25% to about 60%, or about 30% to about 50%.
While gels in general tend to exhibit superior pressure distribution
properties to
standard cushioning materials, such as foam, gels also tend to exhibit greater
thermal conductivity than foam. High thermal conductivity can be a desirable
gel
property, such as in a warm environment where a cooling effect would be
welcomed.
In other situations, however, it may be more desirable to have a lower thermal
conductivity in order to conserve heat near the body of the user. Accordingly,
the
lo present invention is beneficial in that the gel used in the gel layer of
the inventive
support apparatus can have a determinable thermal conductivity.
Thermal conductivity (,\), which is generally reported in terms of watts per
meter per
degree Kelvin (W rri 1 K-1), relates to the ability of a material to transmit
heat under
ts fixed conditions. The lower the value of A, the better insulator the
material will be.
Conversely, the higher the value of A, the better heat conductor the material
will be.
Foam, a typical cushion material for support apparatuses, is known to be a
material
exhibiting good insulating properties. For example, molded foam, such as used
for
20 seat cushions, typically has a A value of about 0.04 W m"1 K-', and foam
used in
construction and building materials typically has aX value of about 0.022 W m-
' K-'.
When a highly insulating material, such as foam, is used in a support
apparatus for
human use, the heat generated by the human body, at first contact with the
foam, is
immediately transferred to the contact surface of the foam. With time, the
transferred
25 heat finds a high resistance to movement through the foam for dissipation.
The
energy (heat) produced continuously by the human body generates an increase in
temperature because the foam is unable to absorb the energy and transport it
away
from the contact area quickly enough. In other words, while the initial warmth
maintained by the contact with the foam may be of a comfortable level, an
eventual
3o heat build-up leads to discomfort for the user.
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Polyurethane gels, and similar gels as described herein, exhibit different
thermal
properties and can generally be considered good conductors of heat compared to
foam. For example, a polyurethane gel can have a A value of about 0.20 W m"1
K71
or greater. Polyurethane gels also typically have a greater density than foam.
For
example, polyurethane gel can typically have a density in the range of about
600 to
about 1,100 Kg/m3, while expanded foam for seat cushions can generally range
from
about 30 to about 85 Kg/m3. Further, polyurethane gels commonly have a high
thermal capacity. This combination of increased ability to transport heat
through the
material, higher material mass per unit area, and high amount of energy needed
to
io increase the material temperature makes a significant difference on the
type of
exchange of heat from the user to the gel over time.
The heat exchange capacity of the gels used in the gel layer according to the
invention therefore further contributes to the good "feel" users desire and
appreciate
in a support apparatus, such as a mattress, pillow, seating apparatus, or the
like.
Accordingly, the presence of the gel layer allows for increased comfort not
only
because of the pressure distribution qualities of the gel but also because of
the
thermal conductivity of the gel and the corresponding ability to move heat
away from
the body and therefore circumvent the eventual heat buildup associated with
many
support apparatuses that can lead to discomfort.
Beneficially, gels useful according to the invention can have their A values
altered
through addition of one or more fillers. Filled gels are useful according to
the
invention because they can be used in a support apparatus to provide increased
comfort and pressure distribution, as previously noted, while also having a
lower
thermal conductivity to lessen the movement of heat away from the body of the
user.
Such lowering of the A value of the gel reduces the "coolness" of the gel.
This can
also increase the subjective comfort of the support apparatus for users who
desire a
feeling of warmth.
Accordingly, in one embodiment of the invention, the gel used in the gel layer
of the
support apparatus further comprises one or more fillers. The filler material
can be
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any material capable of admixture with the gel and that is effective for
altering the A
value of the gel. In a specific embodiment, the filler material is effective
for lowering
the A value of the gel to at least a value indicative of a thermal
conductivity wherein a
perception of coolness of the gel is reduced. In yet another embodiment, the
filler
material is effective for lowering the k value of the gel such that there is a
perception
of warmth from the gel. Accordingly, various types of materials ranging from
solids to
liquids may be used as filler for the gel used in the gel layer according to
the
invention.
io In one embodiment of the invention, the filler comprises a solid material.
Preferentially, the solid material comprises a particulate material. The
average size
of the particulate can vary depending upon the apparatus in which the filled
gel is to
be used and can also vary depending upon the A value desired in the filled
gel. In
one embodiment, the filler can comprise coarse particles. In another
embodiment,
the filler can comprise fine particles (i.e., powders). In yet another
embodiment, the
filler can comprise nanoparticles. In a particular embodiment of the
invention, the
filler material comprises particulates having an average diameter of about
0.05 mm to
about 15 mm. In another embodiment, the particulates have an average diameter
of
about 0.10 mm to about 10 mm, about 0.10 mm to about 5 mm, or about 0.10 to
2o about 1 mm.
In another embodiment of the invention, the filler material comprises hollow
material,
such as microspheres. Such hollow material can be natural or synthetic in
origin, but
are generally expected to be synthetically produced material. For example, the
material can comprise synthetic microspheres. Such microspheres are preferably
formed from a polymer material, such as a polyolefin, particularly an
acrylonitrile
copolymer or polyvinylchloride. In addition to the synthetic microspheres,
other types
of hollow materials having various geometries could also be used in the filled
gel.
For example, in addition to hollow materials that are generally spherical in
nature
(also described as being balloon-like), the hollow materials can also be in
the form of
tubular, rectangular, or other geometric shapes.
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In another embodiment of the invention, the filler comprises a liquid,
particularly an
organic liquid. The liquid is preferably chemically inert to the gel used in
the gel
layer, as well as starting materials, intermediates, and by-products in the
preparation
of the gel (such as isocyanates and polyols in the case of polyurethane gels).
Accordingly, the liquid filler is generally preferably selected from
materials, such as
plasticizers (including oils, resins, and hydrocarbon derivatives),
hydrocarbons and
fuels, alkylbenzenes, and liquid esters. More particularly, the liquid
material can
include amorphous or semicrystalline paraffins, naphthenic oils or resins,
heavy and
light fuels, alkylbenzenes, esters (preferentially products of polyhydric
alcohols with
lo monobasic carboxylic acids), alkylpolyaromatic compound, and vegetable
oils, as
well combinations of the above liquids.
According to a further embodiment of the invention, the filler can comprise
one or
more gasses. For example, the filler can comprise ambient air. In other
embodiments, the gas used as the filler material can comprise substantially
pure
gasses, such as nitrogen gas, or another inert gas, such as argon gas. The gas
can
also comprlse gaseous compounds, such as carbon dioxide gas.
In still another embodiment of the invention, the filler can comprise one or
more
2o active agents. As used herein, active agents are intended to refer to any
additive
capable of providing a therapeutic benefit to a user. For example, the active
agent
can include vitamins, minerals, essential oils, perfumes, and the like.
The filler generally can comprise natural or synthetic materials. For example,
the
filler can comprise natural materials, such as cork, wood, sponge, natural
fibers (e.g.,
cotton, wool, etc), minerals (e.g., mica, or other silicates, or other metal
oxides, such
as aluminates), pumice, and glass (including fibers, beads, etc.). Examples of
synthetic materials useful as fillers in the present invention include
synthetic fibers,
synthetic microspheres, and various other synthetic materials. In one
particular
3o embodiment of the invention, the filler is selected from the group
consisting of cork
pieces, cork flour, wood pieces, wood chips, foam flakes, textile fibers,
textile pieces,
CA 02601023 2007-09-10
WO 2006/100558 PCT/IB2006/000603
paraffins, hollow spheres, synthetic microspheres, mineral particles, glass
beads,
gasses, active-agents, nanoparticYes, and mixtures thereof.
The content of filler present in the gel can vary depending upon the apparatus
in
which the filled gel is to be used and can also vary depending upon the A
value
desired in the filled gel. In one embodiment of the invention, the filler
comprises
about 5 percent to about 95 percent of the filled gel, on a volume basis. In
another
embodiment, the filler comprises about 10 percent to about 90 percent of the
filled
gel, on a volume basis. In still another embodiment, the filler comprises
about 20
io percent to about 80 percent of the filled gel, on a volume basis. In yet
another
embodiment, the filler comprises about 25% to about 75% of the filled gel, on
a
volume basis.
Depending upon the type of filler used in the filled gel and the content of
the filler in
the filled gel, the A value of the filled gel can be altered from the A value
of the gel
without the filler. Preferably, the presence of the filler in the filled gel
causes the filled
gel to exhibit a reduced A value. In other words, it is preferable for the
filled gel to
have a thermal conductivity that is less than the thermal conductivity of the
gel
without the filler.
In one embodiment of the invention, the filled gel has a thermal conductivity
of less
than about 0.20 W m 7 6C-1. In another embodiment, the filled gel has a
thermal
conductivity of less than about 0.15 W m-1 K"1. In still another embodiment,
the
filled gel has a thermal conductivity of less than about 0.10 W m-' K"'. In
one
particular embodiment of the invention, the filled gel has a thermal
conductivity of
less than or equal to about 0.08 W m-' FC-'
In addition to the gel layer (which may or may not include one or more
fillers), the
support apparatus of the invention can further comprise one or more additional
support layers underlying the gel layer. The additional support layer can
include any
type of material generally recognized in the art as being useful for providing
support
to at least a portion of the body of a user. For example, the additional
support layer
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WO 2006/100558 PCT/IB2006/000603
can comprise a layer of foam, which can take on any of the various embodiments
generally useful for providing a cushioning effect or a supportive effect. The
additional support layer can also comprise springs, which are recognized as
being
useful for providing support to the body. The layer of springs can take on any
embodiment known in the art for providing effective support, while also
providing
comfort for the user. For example, the spring layer can comprise a series of
springs
that are at least partially interconnected. Furthermore, the spring layer can
comprise
a series of springs that are present as separate coils. Further additional
embodiments of spring layers are also encompassed by the present invention,
which
io is not intended to be limited by the examples provided above. For example,
the
invention also encompasses apparatuses wherein the additional support layer
comprises other materials known for providing support, including gas (such as
air),
cushioning materials, or paddings, textile layers, and also including
materials
providing structure, such as wood, metal, or rigid plastics.
In one embodiment of the invention, the support apparatus comprises a gel
layer and
at least one additional support layer of a foam material. In another
embodiment of
the invention, the support apparatus comprises a gel layer and at least one
additional
support layer of springs. In still another embodiment of the invention, the
support
2o apparatus comprises a gel layer, at least one additional support layer of
springs, and
at least one additional support layer of a foam material. In one particular
embodiment of the invention, the one or more additional support layers are
positioned underlying the gel layer such that there are no additional support
layers,
positioned above the gel layer.
The additional support layers and the gel layer can be integrally attached or
can be
separate bodies. By integrally attached is intended to mean the layers are
attached
one to another by means such that the two layers are not separable without at
least
partially damaging one or multiple layers. For example, the layers may be
integrally
3o attached, such as by gluing, stapling, sewing, welding, or the like.
Further, the layers
may be integrally attached through chemical bonding. For example, when the gel
layer comprises a polyurethane gel and the additional support layer comprises
a
17
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WO 2006/100558 PCT/IB2006/000603
polyurethane foam, both layers have free isocyanate groups prior to curing (or
maturation) of the gel or foam. Accordingly, a when one layer is allowed to
cure
while adjacent the other layer, chemical bonding between the gel and the foam
can
occur.
Foam support layers are particularly useful in combination with a gel layer,
not only
because of ease of bonding, as described above, but also because of the
various
combinations provided. For example, in one embodiment, convoluted foam may be
used. In another embodiment, the foam may have one or more cavities for
receiving
1o all or part of the gel layer. When such cavities are present, the cavities
may be on a
"top" surface of the foam, a "bottom" surface of the foam, or on both a top
and bottom
surface of the foam.
In specific embodiments of the invention, where the additional support layer
comprises a foam layer, it can be particularly useful for the foam layer to be
of a
specified thickness. For example, where the apparatus is relatively large and
the
foam layer provides a substantial amount of the structure of the apparatus,
such as in
mattress, it can be beneficial for the foam layer to be of a substantial
thickness. For
example, in one embodiment, the additional support layer comprises a foam
layer
2o having a thickness of at least about 5 cm. In further embodiments, the foam
layer
has a thickness of at least about 6 cm, at least about 7 cm, at least about 8
cm, at
least about 9 cm, and at least about 10 cm.
In other embodiments of the invention, it may be preferred for the additional
support
layer to be of a lesser thickness than as described above. For example, when
the
support apparatus is a shoe insert, it is desirable for the apparatus to have
a
minimum thickness. Likewise, in embodiments wherein the apparatus is a
mattress
topper, it is beneficial for the additional support layer to have a minimum
thickness to
avoid adding to the overall profile of the mattress topper. For example, in
one
3o embodiment, it is beneficial for the additional support layer to be a foam
or textile
layer having a thickness of less than about 5 cm. In further embodiments, the
18
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WO 2006/100558 PCT/IB2006/000603
additional support layer preferably has a thickness of less than about 4 cm,
less than
about 3 cm, and less than about 2 cm.
In addition to the gel layer and the additional support layer or layers as
described
s above, the support apparatus of the invention also encompasses the addition
of a
covering overlying the gel layer. The covering can generally comprise any type
of
material commonly used in coverings for the various types of support
apparatuses
encompassed by the invention. Such coverings include natural and synthetic
materials. Further, such coverings can also include padding. For example, when
the
1o support apparatus is a mattress, the covering can be a padded mattress
topper.
Further, any type of upholstering material can be used as the cover in the
present
invention. Accordingly, the presence of the gel layer in no way limits the
types of
covers available for use in covering the support apparatus of the invention.
Furthermore, other types of coverings are also encompassed by the invention.
For
15 example, the covering can comprise a film, such as a polyurethane film, a
coating,
such as a polymer that is non-reactive or non-tacky in a dried or cured state,
or a
foam.
As with the additional support layer, in certain embodiments of the invention,
it may
2o be beneficial for the covering layer to be of a specific thickness.
Generally, the
covering layer should be of minimal thickness to avoid masking the therapeutic
benefits and pleasing feel of the gel layer. For example, in one embodiment,
the
covering comprises a foam layer. According to this embodiment, it is
preferable for
the foam layer to have a thickness of less than about 5 cm. In further
embodiments,
25 the covering preferably has a thickness of less than about 4 cm, less than
about 3
cm, and less than about 2 cm.
The presence of the gel layer in no way limits the scope of support
apparatuses
encompassed by the invention. Accordingly, the support apparatus of the
invention
30 can include apparatuses, such as mattresses, chairs, sofas, recliners,
wheelchairs,
pillows, furniture cushions, office equipment, automobile parts, mattress
toppers, and
the like. In one particular embodiment of the invention, the support apparatus
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WO 2006/100558 PCT/IB2006/000603
comprises a bed mattress. In another embodiment of the invention, the support
apparatus comprises a seating apparatus. In still another embodiment, the
support
apparatus comprises a pillow. In still another embodiment, the support
apparatus
comprises a mattress topper.
The support apparatus of the invention comprising a gel layer overlying at
least one
additional support layer, such as a foam layer and a spring layer, derives
benefit from
multiple aspects of the invention. As previously noted, the gel layer provides
an
improved pressure mapping for the various individuals that may use the support
lo apparatus (i.e., the gel provides improved distribution of the pressure out
and away
from the pressure points). Furthermore, the gel has the capability to absorb
and
transport heat with different parameters than other known support materials,
such as
foam, which generally acts as an insulator and traps heat against a user. The
gel
layer in the apparatus of the invention, however, can further comprise one or
more
fillers and can therefore be made according to predefined specifications to
have a?
value such that the perception of heat flow from the body of the user is
optimized for
comfort. In other words, the filled gel layer can provide a perception of
warmth often
desired by a user but not act as a heat trap, such as foam. Further, when used
in
combination with further layers, such as foam or springs, the various benefits
of the
gel layer can be provided with only a relatively thin gel layer, while the
bulk of the
support apparatus can comprise more conventional materials.
EXPERIMENTAL
The present invention is more fully illustrated by the following examples,
which are
set forth to illustrate the present invention and are not to be construed as
limiting.
EXAMPLE 1
Determination of Gel Mechanical Properties
The mechanical properties of multiple polyurethane gels useful according to
the
present invention were determined using testing methods as described herein.
The
various gel samples were evaluated in terms of hardness and hysteresis, and
the
evaluation results are provided in Table I.
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WO 2006/100558 PCT/IB2006/000603
Table 1
Gel Mechanical Properties
Sample Hardness Hysteresis
ID (kPa) (%) Filler Shape Use
1 7.6 37.4 None Regular Mattress
2 6.0 35.0 None Cylinder Mattress
3 4.4 45.7 None Cylinder Mattress
4 12.0 46.0 Cork Cylinder Mattress
9.7 36.0 Microspheres Cylinder Seat
6 7.9 71.0 None Regular Seat
7 11.0 63.0 None Regular Seat
8 41.0 47.0 None Regular Armpad
9 16.0 68.0 None Regular Armpad
3.1 54.5 None Tower Mattress
11 32.6 51.1 None Tower Armpad
12 92.0 63.0 None Regular -
For each gel sample, the sample shape, optional filler material, exemplary
use,
hardness (measured as force deflection at 40% compression), and percent
5 hysteresis are provided. For sample shape, "regular" indicates a sample 5 cm
wide x
5 cm long x 2.5 cm thick, "cylinder" indicates a cylindrical sample having a
diameter
of 5 cm and being 3 cm thick, and "tower" indicates a sample 5 cm wide x 5 cm
long
x 1.7 mm thick having four square projections arising from the top thereof,
each
being 2 cm wide x 2 cm long x 0.8 cm thick. The use provided for each sample
is
io only provided for purposes of example and should not be construed as
limiting
thereof. Sample ID 12 is provided as a comparative example of a gel that would
not
be useful according to the invention, the hardness of the gel being outside
the
preferred range.
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WO 2006/100558 PCT/IB2006/000603
Many modifications and other embodiments of the inventions set forth herein
will
come to mind to one skilled in the art to which these inventions pertain
having the
benefit of the teaching presented in the foregoing descriptions. Therefore, it
is to be
understood that the inventions are not to be limited to the specific
embodiments
disclosed and that modifications and other embodiments are intended to be
included
within the scope of the appended claims. Although specific terms are employed
herein, they are used in a generic and descriptive sense only and not for
purposes of
limitation.
22
