U.S. patent application number 10/806869 was filed with the patent office on 2005-09-29 for mattress having reticulated viscoelastic foam.
Invention is credited to Barger, Stephen Lynn, Borgart, Guido, Di Stasio, Anthony A., Lavelle, Lawrence P. JR., Lucas, Barry James.
Application Number | 20050210595 10/806869 |
Document ID | / |
Family ID | 34987962 |
Filed Date | 2005-09-29 |
United States Patent
Application |
20050210595 |
Kind Code |
A1 |
Di Stasio, Anthony A. ; et
al. |
September 29, 2005 |
Mattress having reticulated viscoelastic foam
Abstract
A foam mattress includes a reticulated, viscoelastic foam that
makes up the mattress in whole or in part. The reticulated nature
of the viscoelastic foam allows a user to enjoy the benefits of
softness and conformability of a viscoelastic foam and also an
improved breathability. The foam mattress may include a plurality
of zones of foam and/or a plurality of layers of foam, where one of
the layers may be reticulated urethane for improved breathability
and humidity resistance, as well as heat dissipation.
Inventors: |
Di Stasio, Anthony A.;
(Basking Ridge, NJ) ; Lavelle, Lawrence P. JR.;
(Rahway, NJ) ; Borgart, Guido; (Maastricht,
NL) ; Lucas, Barry James; (Oak Ridge, NC) ;
Barger, Stephen Lynn; (High Point, NC) |
Correspondence
Address: |
John H Thomas
John H Thomas PC
536 Granite Avenue
Richmond
VA
23226
US
|
Family ID: |
34987962 |
Appl. No.: |
10/806869 |
Filed: |
March 23, 2004 |
Current U.S.
Class: |
5/740 ;
5/690 |
Current CPC
Class: |
A47C 27/148 20130101;
A47C 27/144 20130101; A47C 27/15 20130101; A47C 21/046 20130101;
A47C 27/146 20130101 |
Class at
Publication: |
005/740 ;
005/690 |
International
Class: |
A47C 027/14 |
Claims
What is claimed is:
1. A foam mattress comprising a reticulated, viscoelastic foam,
wherein the viscoelastic foam is comprised of at least about
fifteen percent by weight of a viscoelastic polyol.
2. A foam mattress as described in claim 1, wherein the foam
mattress comprises a plurality of layers of foam, and one of the
layers comprises the reticulated, viscoelastic foam.
3. A mattress as described in claim 1, wherein the foam mattress
comprises a plurality of zones of foam, and one of the zones
comprises the reticulated, viscoelastic foam.
4. The mattress as described in claim 1, wherein the mattress
comprises three or more layers of foam, and an outside layer
comprises the reticulated, viscoelastic foam.
5. The mattress as described in claim 4, wherein the outside layer
covers substantially the entire length and width of the
mattress.
6. The mattress as described in claim 2, wherein a second layer
comprises a reticulated polyurethane foam, and the reticulated
viscoelastic and reticulated polyurethane foams are adhered to each
other.
7. The mattress as described in claim 1, wherein the viscoelastic
foam is comprised of about 15% to about 75% by weight of
viscoelastic polyol.
8. The mattress as described in claim 1, wherein the viscoelastic
foam is comprised of about 60% to about 70% by weight of
viscoelastic polyol.
9. The mattress as described in claim 2, further wherein the
mattress comprises a plurality of zones of foam.
10. The mattress as described in claim 9, wherein the foam mattress
comprises at least three layers of foam and at least three zones of
foam.
11. The mattress as described in claim 10, wherein the foam
mattress has a symmetrical layer construction.
12. The mattress as described in claim 10, wherein the foam
mattress has a symmetrical zone construction.
13. The mattress as described in claim 11, wherein the foam
mattress has a symmetrical zone construction.
14. The mattress as described in claim 1, wherein the foam mattress
comprises five layers of foam, and wherein the outside layers of
foam comprise latex, the layers immediately adjacent the outside
layers comprise the viscoelastic foam, and a central layer
comprises reticulated polyurethane foam.
Description
[0001] The present invention relates to foam mattresses, and
specifically foam mattresses made, at least in part, from
reticulated, viscoelastic foam.
BACKGROUND OF THE INVENTION
[0002] Foam mattresses generally have been well known for many
years. Standard polyurethane foam materials provide good cushion.
The specific polyurethane material may be varied to make a mattress
softer or firmer. Traditional polyurethane foam mattresses are
known for their springy and bouncy nature.
[0003] Another well-known material for use in foam mattresses is
viscoelastic foam. This foam, also referred to as "memory/slow
recovery" foam, has low resilience and naturally shapes or conforms
to a person's body. This particular foam material is also effective
to dampen sound and vibration. While viscoelastic foam is very
popular for use as a mattress or component thereof, a major
drawback to it is its inability to "breathe". A person may overheat
and excessively perspire, because there is insufficient ventilation
in the foam to allow air and moisture flow. Also, the slow recovery
aspect of the foam may make turning over difficult or getting out
of a bed difficult. The viscoelastic foam is also very sensitive to
temperature and humidity.
[0004] Foam mattresses are also known that have multiple layers
and/or zones that are made up of different foam materials. In this
way, different foams are directed to specific purposes such as
support or softness. Many of these multiple zone and multiple layer
mattresses are one-sided (cannot be flipped) or uni-directional
(cannot be turned around).
SUMMARY
[0005] Accordingly, it is an object of the present invention to
overcome the foregoing drawbacks and to provide a foam mattress
that includes a reticulated, viscoelastic foam. The mattress may
have multiple zones and multiple layers. The reticulated nature of
the viscoelastic foam allows a user to enjoy the benefits of the
softness and conformability of a viscoelastic foam and also an
unprecedented breathability.
[0006] In one example, a foam mattress comprises a reticulated,
viscoelastic foam, wherein the viscoelastic foam is comprised of at
least about 15% by weight of a viscoelastic polyol. The foam
mattress may comprise a plurality of layers of foam, and one of the
layers may comprise the reticulated, viscoelastic foam. The foam
mattress may also comprise a plurality of zones of foam, and one of
the zones of foam may comprise the reticulated viscoelastic foam.
The mattress may comprise three or more layers of foam, and an
outside layer comprises the reticulated, viscoelastic foam. The
outside layer of the mattress may cover substantially the entire
length and width of the mattress. In a multiple layer mattress, a
first layer may comprise a reticulated viscoelastic foam and a
second layer may comprise a reticulated polyurethane foam, and the
reticulated viscoelastic and reticulated polyurethane foams are
adhered to each other. The viscoelastic foam may be comprised of
about 15% to about 75% by weight of viscoelastic polyol, or, in
another example, about 60% to about 70% by weight of viscoelastic
polyol. In further examples, the foam mattress may comprise at
least three layers of foam and/or at least three zones of foam. The
mattress may have a symmetrical layer construction and/or a
symmetrical zone construction. Still further alternatively, the
foam mattress may comprise five layers of foam, wherein the outside
layers of foam comprise latex, the layers immediately adjacent the
outside layers comprise viscoelastic foam, and a central layer
comprises reticulated polyurethane foam.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a side elevation view of an embodiment of a
symmetric, multiple zone, five-layer foam mattress.
[0008] FIG. 2 is a side-elevation view of a three-layer, multiple
zone foam mattress.
[0009] FIG. 3 is a side elevation view of another three-layer,
multiple zone foam mattress.
DETAILED DESCRIPTION
[0010] The foam mattress discussed herein include the use of a
reticulated, viscoelastic foam alone and as a component in a
composite mattress. By the process of reticulation, a viscoelastic
foam can achieve enhanced ventilation properties, thereby making it
more attractive for use as a mattress or a part thereof.
[0011] For the purposes of discussion herein, the term
"viscoelastic foam" means foam formed using a viscoelastic polyol,
and specifically at least about 15% by weight of the viscoelastic
polyol in the finished foam. Less than about 15% by weight of
viscoelastic polyol does not process well, and it is believed that
the resulting foam does not have significant viscoelastic
properties. Weight percent ranges of viscoelastic polyol in the
finished foam include about 15% to about 75%, and, for a further
example, about 60% to about 70%.
[0012] The term "reticulated viscoelastic foam" means a
viscoelastic foam that has been subjected to a reticulation
process. Reticulation is a means by which the thin window membranes
are removed from a foam to create an open cell structure that is
opened to air and moisture flow. The process of reticulation
involves placing a block of foam into a reticulation chamber,
evacuating the chamber under vacuum to remove the air from the
chamber and from within the foam, filling the chamber and foam with
hydrogen and oxygen to a fuel loading of a predetermined ratio of
hydrogen/oxygen to a specific pressure, and then igniting the fuel
mixture to create an explosive wave that removes the membranes of
the foam by pressure and heat. In addition to creating an open cell
structure that allows flow through the foam, the reticulation
process also increases the strength properties of the foam.
Viscoelastic Formulation Technology
[0013] Viscoelastic or "memory/slow recovery" foams have a number
of very unique performance characteristics. This high quality foam
tends to be low resilience, shape or body conforming, and able to
dampen both sound and vibration or shock. In addition, this
material is sensitive to both temperature and humidity conditions
in the ambient environment.
[0014] These foams can be produced by a number of different
chemical approaches. In general these formulations will certainly
include a high hydroxyl polyether polyol and a number of potential
isocyanate compounds to include MDI, TDI (80/20) and TDI (65/35)
and blends thereof. The products are usually foamed at low
isocyanate index with special silicone surfactants to control cell
structure and unique additives to operate in a mixture very
different from conventional polyether urethane materials. These
specialty silicone additives will assist in the cell opening
process as well as control the overall structure of the urethane
cells. The low index will promote cell opening as well as restrain
the foam from shrinkage on curing. The formulation at a low
isocyanate index will also give the resultant foam a very improved
level of softness and feel for bedding applications, especially if
some performance additives are used to promote these properties.
Since the available isocyanate is limited or "under indexed," this
promotes a competition for these molecules between the water and
the polyol system thereby making the formulation technique very
different from conventional urethanes.
[0015] With the formulation challenges of viscoelastic foam
materials, the processing latitude is one of the most critical.
This latitude being very "fine edge" really makes the processing of
this foam drastically different from conventional urethanes, and
the chemical technology that is used can significantly alter the
performance of the product. The foams that result can vary
significantly in density as well as firmness. Therefore these foams
require very different chemical and or processing approaches as
compared to conventional urethane foam. The driving formulation
criteria are to specifically control the viscosity (recovery time)
of the product to customize the foam's use in bedding platforms.
Temperature sensitivity is always an issue as the intent is to have
a foam product that operates or maintains its desired firmness in a
broad range of ambient temperature conditions. The feel, recovery
and firmness of these products can be markedly affected by slight
variations in bedroom temperature. If the formulation of the
viscoelastic foam is not uniquely adjusted for bedding
applications, the viscous nature of the material will also change
with time and prolonged use in sleep platform.
[0016] An exemplary viscoelastic foam component is a product from
Bayer (VE-1000), which has good formulating latitude with 80/20 TDI
at 100 index. Of course, other viscoelastic polyols may be used and
are known to those of skill in the art. The viscoelastic foam
produced using the VE-1000 viscoelastic polyol had excellent
shaping conformance and very reduced sensitivity to ambient
temperature conditions. This viscoelastic polyol can be used with
conventional polyether polyol materials such as ARCOL F-3022,
F-3222, F-3040, or P-2000 (Boyer Ultracell Polyl 2000). These
polyol streams can be mixed with a conventional high solids polymer
polyol material like HS-100, which has been the standard of the
industry for many years, to produce a firmer version of the
viscoelastic material for high-end mattress compositions. The other
additive unique to this viscoelastic product is a foam modifier
DP-1022 (Lyondell Chemical) that assists the overall performance of
the foam over a wide range of foam densities and firmness. The
balance of the formulation for the viscoelastic foam may be
composed of standard chemical raw materials that are used in
conventional polyether foams, which include silicone surfactant,
amine catalyst and flame retardant additives.
[0017] The following table lists the formulating materials that
give viscoelastic foam its unique properties and the function they
contribute to the material. The range levels are well within the
formulation expertise of those who are familiar with the
formulation criteria for conventional flexible urethane foam.
1 Component Range (pph) Primary Function VE-1000 50-100 Viscous
Character F-3022 0-50 Elastic Character HS-100 0-50 Firmness P-2000
0-50 Firmness DP-1022 0-3 Damping Character & Strength TDI
(80/20) Index 75-110 Firmness Pph = parts per hundred parts
polyol
[0018] Low Density Viscoelastic Formulation Examples
2 Grade 3 pcf 2.8 pcf 3.4 pcf Component 12 IFD 15 IFD 24 IFD
VE-1000 70 75 65 F-3022 30 25 HS-100 35 DP-1022 2.0 1.5 1.5 TDI
(80/20) Index 95 100 1.5
[0019] The table above shows how manipulation of the key
viscoelastic components could be done to alter the density and IFD
of some respective low-density materials. A similar set of examples
can be developed for High Density materials as well where
viscoelastic characteristics are required.
[0020] Viscoelastic foams have a unique isocyanate-reaction
composition. The mixture typically has a polyester or
polyoxyalkylene monol and a polyester or poloxyalkylene triol,
usually with a chain extending material or a cross-linker. The
monol (polyether or polyester), has one hydroxyl group on each
molecule and an average equivalent weight greater than 1000. The
average molecular weight of these materials is greater than 1000.
In one example, the monol has an average equivalent weight greater
than 1500, and in another example an equivalent weight greater than
2000. The hydroxyl number for these materials would be at least
about 56 mg KOH/g.
[0021] The viscoelastic polyols (like VE-1000) are usually produced
by the reaction of a monoalcohol with multiple equivalents of an
epoxide material like ethylene oxide (EO) or propylene oxide (PO)
and mixtures thereof. These monols can have any desired arrangement
of oxyalkylene units where they are PO polymers, EO-capped
materials, blocked EO-PO copolymers, random EO-PO copolymers or PO
polymers that are finished with a mixture of PO and EO to arrive at
the desired hydroxyl content.
[0022] The all PO version of the above monols, that have hydroxyl
numbers less than or equal to 56 mg KOH/gm., significantly expand
the processing window for making these viscoelastic foam materials.
If one were to "EO tip" the above monols, with a mixture of EO and
PO and produce a material with 15 to 50% primary hydroxyl groups,
the foam properties and processing of these viscoelastic foams
would be significantly improved. The "EO-Capped" version of these
monols with high (80% or greater) primary hydroxyl content are
classified as reactive monols and show very high reactivity with
isocyanate species. Although all PO monols are great for improved
processing latitude, they can tend to make the viscoelastic foam
very slick or oily to the touch. The reactive monols can alleviate
this oily feel and provide viscoelastic foam with excellent feel
and recovery. The polyester or polyoxyalkylene monol (viscoelastic
polyol) is used in a range of at least about 15% to 70% by weight
of the foam mixture based on the amount of isocyanate available in
the mixture, with the most another example being a range of 25-50%
by weight. This isocyanate-polyol mixture has polyols with
functionalities of at least 2 or greater with, for example, a
hydroxyl functionality in the range of 3 to 6. The triol materials
are one of the species for the viscoelastic foam products discussed
here. These polyols have average equivalent weights that are less
than 600 or less than 400. The hydroxyl number of these polyols is
approximately 94 mg KOH/gm with in one example materials at a
hydroxyl number greater than 140 mg KOH/gm.
[0023] Other polyols in this case are polyoxyalkylene materials
(prepared in a similar manner to monols above but with two or more
active hydrogen sites) and are present at a load of 30 to 85% by
weight of the isocyanate mixture but may also be suited for
mattress applications at 40 to 70% by weight of the foam
mixture.
[0024] In addition to the monol and polyol components, the
viscoelastic foam formulations may have either a chain extender or
cross linker material to provide increased strength. These
materials will be used in the range of 0.1 to 5.0% by weight or
alternatively, 0.5 to 3.0% by weight. On a molecular weight basis
these chain extenders or cross linkers should be less than 300
g/mole or alternatively, less than 200 g/mole.
[0025] The isocyanate will have two or more free --NCO groups per
molecule, and those that are common to the flexible urethane foam
industry include TDI (80/20), TDI (65/35) and MDI (conventional and
polymeric), and HDI. The isocyanate component may also be a blend
of some or all of the materials noted in the above isocyanate
reference. Although good quality viscoelastic foams can be produced
in the broad range of isocyanate index for conventional urethanes
(85-130), an index for superb quality viscoelastic materials is an
isocyanate index below about 110. In one example, the index is
about 100.
[0026] The following data demonstrates some of the physical
properties that are about the same and that are different between
various foams that are used in commercial mattresses. The foams are
viscoelastic, high resiliency, and conventional formulations.
Foam Property Data Commercial Mattress Foams
Viscoelastic-HR-Conventional
[0027]
3 PROPERTY VISCOELASTIC HR CONVENTIONAL Density (lbs/cu.ft) 2.8 pcf
2.5 pcf 2.33 pcf Resilience (%) 11 58 53 Elongation (%) 159 150 348
Tear (pli) 0.8 1.30 1.86 75% HACS % 5.6 10.7 4.2
[0028] The greatest property difference noted is the resilience of
the viscoelastic product. With the foam characteristics of slow
recovery, body conforming nature, vibration dampening and
temperature sensitivity, it can be seen that the viscoelastic
product is significantly different from the HR and Conventional
materials that have been used in commercial bedding in the past. In
an overall view of property characteristics, the HR and
conventional urethane foams do not exhibit any of the unique
characteristics of the viscoelastic material. These unique
properties are a function of the high hydroxyl polyol and polyol
blends used along with low index combinations of TDI, MDI and some
other specialty isocyanate. In some very unique cases some
distinctive silicone surfactants are employed as well as some
strength additives to complete the formulation matrix that is
different than the conventional flexible urethane system.
Reticulated Viscoelastic Foam
[0029] A viscoelastic foam as described earlier herein is subjected
to a reticulation process in order to increase the "breathability"
of the foam. An intrinsic characteristic of viscoelastic foam is
its relative high density and fine cell structure. Reticulation of
a viscoelastic foam is obtained by using known thermal reticulation
processes that have been used for fine cell, white foam materials.
These thermal reticulation processes have enough energy to
reticulate the viscoelastic foam. The thermal reticulation
processes also have inherent provisions to reduce the amount of
scorch that can occur as a result of the combustion nature of the
reticulation process in white foams by adjusting the
oxygen/hydrogen level during the fuel fill. Specific processes
parameters will vary depending on each type of foam that may be
used. These process parameters are known to those of skill in the
reticulation art.
[0030] Analysis has been performed to fully demonstrate the effect
of the thermal reticulation process on a viscoelastic foam. The
attached table sets forth the physical properties associated with a
regular, commercially-available foam (Novacomfort.RTM.--Vita). The
viscoelastic polyol in this particular foam amounts to
approximately 60% of the weight of the finished foam.
4 Visco-Elastic Foam Physical Test Results Reticulated
Non-Reticulated Density 3.39 3.43 25% CFD, psi 0.17 0.17 Ball
Rebound 10% 11% Tensile Strength, psi 7.8 8.5 Elongation 170% 220%
Tear Strength, psi 0.7 0.8 Air Flow, cfm 0.96 4 All tests completed
according to ASTM D 3574-91
[0031] As demonstrated in this table, the significant change in
physical properties relates to the air and liquid flow through the
foam. The resulting improvement in the air flow in the reticulated
viscoelastic foam is greater than four times over an existing,
non-reticulated viscoelastic foam.
[0032] Comfort Zone Mattress
[0033] FIGS. 1-3 illustrate three examples of foam mattresses 10,
100 and 200 respectively, that include a reticulated viscoelastic
foam. Each of these mattresses has multiple layers 50 and multiple
zones 40. For the purposes herein, the term "multi-layer mattress"
includes a mattress that has more than one layer of material across
its length and width in the context of the thickness or depth of
the mattress. As shown in FIG. 1, there are five layers 50 across
the depth of the mattress 10. The layers 50 of the mattress 10 are
distinguished from the "zones" 40 of the mattress in that the zones
are the longitudinal sections that are shown. As demonstrated in
FIG. 1, the mattress 10 has seven zones 40. In other words, the
zones 40 are the cross sections of the longitudinal length of the
mattress 10 where different foam materials may be used.
[0034] The mattresses described in the following, and as shown in
the figures, are foam mattresses that incorporates different foam
components adhered to each other in order to obtain improved
ventilation, durability, and comfort for the mattress. The
difference between the mattresses shown in FIGS. 1, 2 and 3 relate
to the number of layers and to the configuration of the inner
sections of the zones in the mattresses. In each case, the top or
outside layer 20 and 20' in FIG. 1 and 120 and 220 in FIGS. 2 and 3
of the mattress 10, 100 and 200 is formed of a latex material. The
latex is flexible and durable and has an open cell structure which
ventilates well. The purpose of the top layer 20 and 20' in FIG. 1
and 120 and 220 in FIGS. 2 and 3 of the mattress 10, 100 and 200 is
for comfort and suppleness. An example of an acceptable latex is
referred to as a Talalay.RTM. Latex. This latex is incorporated as
a complete layer that covers the entire length and width of a
mattress.
[0035] A reticulated viscoelastic foam, for instance the
Novacomfort.RTM. foam that has been reticulated, is incorporated
into two different sections 26 and 26' in FIG. 1 and 126 and 227 in
FIGS. 2 and 3 in the second layer of the mattresses shown in FIGS.
1-3. The foam is incorporated for use under the parts of the body
where pressure may otherwise build up, for instance the
shoulders.
[0036] A high resiliency foam (HR 10548--Vita-Interfoam, B.V.) is
used to support the hip zone 27 and 27' in FIG. 1 and 127 and 227
in FIGS. 2 and 3 of the mattress.
[0037] A high density polyurethane foam is used in the zones 25 and
25' in FIG. 1 and 125 and 225 in FIGS. 2 and 3 of the mattress for
the lumbar and head and foot. An acceptable high density foam is a
Pantera.RTM. 2130HD foam.
[0038] The central layer 30 of the mattress shown in FIG. 1 (and
the bottom layer 130 and 230 of the mattresses shown in FIGS. 2 and
3) is a reticulated polyurethane foam having a course structure and
open cells. The open structure allows for the circulation of air
and escape of moisture from the mattress as shown by the arrows in
FIG. 1. It also enhances temperature distribution through maximum
ventilation. An example of a commercial polyurethane foam
acceptable for this use is a Calipore.RTM. foam (Caligen Foam,
Ltd.) Or EZ-Dri/FilterCrest (Crest Foam Industries). In alternative
embodiments, this central layer 30 of Calipore.RTM. or open cell
polyurethane foam may include a heating element 31 to better dry
out and improve the air flow of the mattress.
[0039] Each of the mattresses 10, 100 and 200 shown in FIGS. 1-3
includes a symmetrical zone 40 construction. In other words, the
mattress may be turned around head to foot in an ordinary rotation
by a user.
[0040] In FIG. 1, the mattress 10 is further symmetrical across the
layers 50. In this way, the mattress 10 may be conveniently flipped
or turned around as a result of its symmetry across both its depth
and its length. In one example, the mattress 10 shown in FIG. 1 is
200 mm thick (approximately 8 inches). There are five layers 50.
There are seven unique zones 40 designed to follow the contour of
the body (head/foot, shoulder, lumbar, hip, lumber, shoulder,
head/foot). A heating system 31 is incorporated in the middle layer
30 to dry the mattress 10 from the inside and keep it warm during
cold nights.
[0041] While the invention has been described with reference to
specific embodiments thereof, it will be understood that numerous
variations, modifications and additional embodiments are possible,
and all such variations, modifications, and embodiments are to be
regarded as being within the spirit and scope of the invention.
* * * * *