U.S. patent application number 16/397485 was filed with the patent office on 2019-08-15 for viscoelastic polyurethane foam with aqueous polymer dispersion.
The applicant listed for this patent is Dow Global Technologies LLC, Rohm and Haas Company. Invention is credited to Kaoru Aou, Paul Cookson, Joseph Jacobs, Qinghao Meng.
Application Number | 20190248951 16/397485 |
Document ID | / |
Family ID | 55070179 |
Filed Date | 2019-08-15 |
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United States Patent
Application |
20190248951 |
Kind Code |
A1 |
Aou; Kaoru ; et al. |
August 15, 2019 |
Viscoelastic Polyurethane Foam with Aqueous Polymer Dispersion
Abstract
A reaction system for forming a viscoelastic polyurethane foam
includes an isocyanate component that has at least one isocyanate
and an isocyanate-reactive component that is a mixture formed by
adding at least a polyol component, an additive component, and a
preformed aqueous polymer dispersion. The mixture includes, based
on the total weight of the mixture, from 50.0 wt % to 99.8 wt % of
a polyol component including at least one polyether polyol, from
0.1 wt % to 50.0 wt % of an additive component including at least
one catalyst, and from 0.1 wt % to 6.0 wt % of a preformed aqueous
polymer dispersion. The preformed aqueous polymer dispersion has a
solids content from 10 wt % to 80 wt %, based on the total weight
of the preformed aqueous polymer dispersion, and is one of an
aqueous acid polymer dispersion or an aqueous acid modified
polyolefin polymer dispersion in which the polyolefin is derived
from at least one C.sub.2 to C.sub.20 alpha-olefin.
Inventors: |
Aou; Kaoru; (Lake Jackson,
TX) ; Jacobs; Joseph; (Yardley, PA) ; Meng;
Qinghao; (Angleton, TX) ; Cookson; Paul;
(Schindellegi, CH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Dow Global Technologies LLC
Rohm and Haas Company |
Midland
Collegeville |
MI
PA |
US
US |
|
|
Family ID: |
55070179 |
Appl. No.: |
16/397485 |
Filed: |
April 29, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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15534129 |
Jun 8, 2017 |
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PCT/US2015/065680 |
Dec 15, 2015 |
|
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16397485 |
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62093054 |
Dec 17, 2014 |
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62166261 |
May 26, 2015 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C08G 18/4837 20130101;
C08G 18/1833 20130101; C08G 18/7664 20130101; C08L 75/08 20130101;
C08G 2101/0008 20130101; C08G 18/244 20130101; C08G 18/163
20130101; C08G 18/2063 20130101; C08G 18/4816 20130101; C08G
2101/005 20130101; C08G 18/18 20130101; C08G 18/485 20130101; C08G
2350/00 20130101; C08G 18/7671 20130101; C08G 2101/0083 20130101;
C08G 18/4845 20130101; C08L 75/08 20130101; C08L 33/02
20130101 |
International
Class: |
C08G 18/76 20060101
C08G018/76; C08G 18/18 20060101 C08G018/18; C08G 18/24 20060101
C08G018/24; C08G 18/48 20060101 C08G018/48; C08L 75/08 20060101
C08L075/08; C08G 18/20 20060101 C08G018/20; C08G 18/16 20060101
C08G018/16 |
Claims
1-12. (canceled)
13. A method for forming a viscoelastic polyurethane foam that has
a resiliency of less than 20% as measured according to ASTM D 3574,
the method comprising: providing a preformed aqueous dispersion
that has a solids content from 10 wt % to 80 wt % based on the
total weight of the preformed aqueous polymer dispersion, the
preformed aqueous dispersion being one of an aqueous acid polymer
dispersion or an aqueous acid modified polyolefin polymer
dispersion in which the polyolefin is derived from at least one
C.sub.2 to C.sub.20 alpha-olefin; preparing an isocyanate-reactive
component by mixing at least a polyol component, an additive
component, and the preformed aqueous dispersion, the resultant
mixture including: from 50.0 wt % to 99.8 wt % of a polyol
component, based on the total weight of the mixture, the polyol
component including at least one polyether polyol, from 0.1 wt % to
50.0 wt % of an additive component, based on the total weight of
the mixture, that includes at least one catalyst and at least one
surfactant, and from 0.1 wt % to 6.0 wt % of the preformed aqueous
polymer dispersion, based on the total weight of the mixture;
providing an isocyanate component that includes at least one
isocyanate such that an isocyanate index of the reaction system is
from 50 to 110; and allowing the isocyanate component to react with
the isocyanate-reactive component to form the viscoelastic
polyurethane foam.
14. The method as claimed in claim 13, wherein the preformed
aqueous polymer dispersion is a continuous liquid phase component
at ambient conditions of room temperature and atmospheric pressure
and is derived from a liquid phase and a solid phase, the liquid
phase being water and the solid phase being an acid or an
acid-modified polyolefin in which the polyolefin is derived from at
least one C.sub.2 to C.sub.20 alpha-olefin.
15. The method as claimed in claim 13, wherein the preformed
aqueous polymer dispersion is a continuous liquid phase component
at ambient conditions of room temperature and atmospheric pressure
and is derived from a liquid phase and a solid phase, the liquid
phase being water and the solid phase including an ethylene-acrylic
acid copolymer.
16. The method as claimed in claim 13, wherein the preformed
aqueous polymer dispersion includes at least one ethylene-acrylic
acid copolymer that has an acrylic acid content from 10 wt % to 70
wt %, based on the total weight of the ethylene-acrylic acid
copolymer.
17. The method as claimed in claim 13, wherein the additive
component includes at least one surfactant.
18. The method as claimed in claim 13, wherein the additive
component includes water that accounts for less than 2.0 wt % of
the total weight of mixture.
19. The method as claimed in claim 13, wherein the polyol component
includes at least one polyoxyethylene-polyoxypropylene polyether
polyol that has an ethylene oxide content of at least 50 wt %, has
a nominal hydroxyl functionality from 2 to 4, and accounts for 35
wt % to 90 wt % of the isocyanate-reactive component.
20. The method as claimed in claim 13, wherein the polyol component
includes a blend of at least three polyols, the blend including:
(i) a polyoxyethylene-polyoxypropylene polyether polyol that has an
ethylene oxide content of at least 50 wt %, has a nominal hydroxyl
functionality from 2 to 4, has a number average molecular weight
from 700 g/mol to 1500 g/mol, and accounts for 35 wt % to 90 wt %
of the isocyanate-reactive component, (ii) a
polyoxypropylene-polyoxyethylene polyether polyol that has an
ethylene oxide content of less than 20 wt %, has a nominal hydroxyl
functionality from 2 to 4, has a number average molecular weight
greater than 1500 g/mol and less than 6000 g/mol, and accounts for
5 wt % to 50 wt % of the isocyanate-reactive component, and (iii) a
polyoxypropylene polyether polyol that has a nominal hydroxyl
functionality from 2 to 4, has a number average molecular weight
from 700 g/mol to 1500 g/mol, and accounts for 5 wt % to 50 wt % of
the isocyanate-reactive component.
Description
FIELD
[0001] Embodiments relate to viscoelastic polyurethane foams
prepared using a preformed aqueous polymer dispersion and a method
of manufacturing such viscoelastic polyurethane foams.
INTRODUCTION
[0002] Flexible, viscoelastic polyurethane foam (also known as
slow-recovery foam and high-damping foam) is characterized by
relatively slow, gradual recovery from compression and the
viscoelastic foam may have a relatively lower resiliency. Exemplary
applications for viscoelastic foam utilize the foam's
characteristics such as shape conforming, energy attenuating,
and/or sound damping. For example, the viscoelastic polyurethane
foam may be used in comfort applications (such as bedding and
pillows), shock absorbing applications (such as in athletic padding
and helmets), and in soundproof applications (such as automotive
interiors).
SUMMARY
[0003] Embodiments may be realized by providing a reaction system
for forming a viscoelastic polyurethane foam that has a resiliency
of less than or equal to 20% as measured according to ASTM D 3574,
the reaction system including an isocyanate component that has at
least one isocyanate and an isocyanate index of the reaction system
is from 50 to 110; and an isocyanate-reactive component that is a
mixture formed by adding at least a polyol component, an additive
component, and a preformed aqueous polymer dispersion. The mixture
includes from 50.0 wt % to 99.8 wt % of a polyol component, based
on the total weight of the mixture, the polyol component including
at least one polyether polyol, from 0.1 wt % to 50.0 wt % of an
additive component, based on the total weight of the mixture, that
includes at least one catalyst, and from 0.1 wt % to 6.0 wt % of a
preformed aqueous polymer dispersion, based on the total weight of
the mixture. The preformed aqueous polymer dispersion has a solids
content from 10 wt % to 80 wt %, based on the total weight of the
preformed aqueous polymer dispersion, and is one of an aqueous acid
polymer dispersion or an aqueous acid modified polyolefin polymer
dispersion in which the polyolefin is derived from at least one
C.sub.2 to C.sub.20 alpha-olefin.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] FIG. 1 illustrates an exemplary schematic representation of
a melt-extrusion apparatus used to prepare a preformed aqueous
polymer dispersion.
[0005] FIG. 2 illustrates the wetting effect of Working Example
12.
[0006] FIG. 3 illustrates the wetting effect of Comparative Example
D.
DETAILED DESCRIPTION
[0007] A viscoelastic polyurethane foam may be characterized as
having a resiliency that is less than or equal to 20% as measured
according to ASTM D 3574 (may also be referred to as a Ball Rebound
Test). For example, the resiliency may be less than 15%, less than
10%, less than 8%, and/or less than 7 wt %. The resiliency may be
greater than 1%. Viscoelastic polyurethane foams may be prepared
using a reaction system that includes an isocyanate component and
an isocyanate-reactive component. In particular, the viscoelastic
foam is formed as the reaction product of the isocyanate component
and the isocyanate-reactive component. The isocyanate component
includes at least one isocyanate such as an isocyanate-terminated
prepolymer and/or a polyisocyanate. The isocyanate-reactive
component includes at least one compound having an isocyanate
reactive hydrogen atom group, such as a hydroxyl group and/or an
amine group. The isocyanate component and/or the
isocyanate-reactive component may include an additive such a
catalyst, a curing agent, a surfactant, a blowing agent, a
polyamine, and/or a filler.
[0008] According to embodiments, the isocyanate-reactive component
includes at least three components. In particular, the
isocyanate-reactive component includes a polyol component, an
additive component, and a preformed aqueous polymer dispersion.
[0009] The polyol component accounts for 50.0 wt % to 99.8 wt %
(e.g., 60.0 wt % to 99.8 wt %, 70.0 wt % to 99.5 wt %, 80.0 wt % to
99.0 wt %, 90.0 wt % to 99.0 wt %, etc., so as to be the majority
component in the reaction system for forming the viscoelastic
polyurethane foam) of the isocyanate-reactive component. The polyol
component includes at least one polyether polyol and may optionally
include at least one polyester polyol.
[0010] The additive component may include a catalyst, a curing
agent, a surfactant, a blowing agent, a polyamine, water, and/or a
filler. The additive component accounts for 0.1 wt % to 50.0 wt %
(e.g., 0.1 wt % to 40.0 wt %, 0.1 wt % to 30.0 wt %, 0.1 wt % to
20.0 wt %, 0.1 wt % to 15.0 wt %, 0.1 wt % to 10.0 wt %, 0.1 wt %
to 5.0 wt %, etc.) of the additive component, based on the total
weight of the isocyanate-reactive component. The additive component
in exemplary embodiments includes at least one catalyst and at
least one surfactant.
[0011] The preformed aqueous polymer dispersion accounts for 0.1 wt
% to 6.0 wt % (e.g., 0.1 wt % to 5.0 wt %, 0.1 wt % to 4.1 wt %,
0.1 wt % to 4.0 wt %, 0.1 wt % to 3.5 wt %, 0.1 wt % to 3.0 wt %,
0.4 wt % to 2.5 wt %, 0.5 wt % to 2.4 wt %, etc.) of the
isocyanate-reactive component. The preformed aqueous polymer
dispersion is one of an aqueous acid polymer dispersion or an
aqueous acid-modified polyolefin polymer dispersion in which the
polyolefin is derived from at least one C.sub.2 to C.sub.20
alpha-olefin (e.g., at least one C.sub.2 to C.sub.10 alpha-olefin
and/or C.sub.2 to C.sub.8 alpha-olefin). The preformed aqueous
polymer dispersion has a solids content from 10 wt % to 80 wt %,
based on the total weight of the preformed aqueous polymer
dispersion. The aqueous polymer dispersion may be a combination of
one or more aqueous polymer dispersions that are used to form the
viscoelastic polyurethane foam.
[0012] The viscoelastic foam prepared using the preformed aqueous
polymer dispersion additive may have an air flow greater than 5.0
standard cubic foot per minute (scfm) (approximately 2.4 L/s) under
standard conditions. The viscoelastic foam may have a recovery time
(also referred to as viscoelastic recovery time) of less than 20
seconds (e.g., less than 10 seconds and/or less than 5 seconds).
For example, a viscoelastic polyurethane foam may be prepared that
has an increaseed air flow without sacrificing resiliency.
Preformed Aqueous Polymer Dispersion
[0013] The aqueous polymer dispersion includes at least (a) a base
polymer including an acid polymer and/or an acid-modified
polyolefin polymer and (b) a fluid medium (in this case water), in
which the base polymer is dispersed in the fluid medium. The
preformed aqueous polymer dispersion may be a continuous liquid
phase component at ambient conditions of room temperature and
atmospheric pressure and is derived from a liquid phase (i.e., the
fluid medium) and a solid phase (i.e., the base polymer).
[0014] In embodiments, the preformed aqueous polymer dispersion is
one of an aqueous acid polymer dispersion or an aqueous
acid-modified polyolefin polymer dispersion in which the polyolefin
is derived from at least one C.sub.2 to C.sub.20 alpha-olefin. By
aqueous acid polymer dispersion it is meant an aqueous dispersion
prepared with an acid based polymer. By aqueous acid-modified
polyolefin polymer dispersion it is meant an aqueous dispersion
prepared with an acid-modified polyolefin polymer. By derived from
at least one C.sub.2 to C.sub.20 alpha-olefin it is meant that the
polyolefin is a polymer prepared using at least one alpha-olefin,
in which each alpha-olefin used is one of a C.sub.2 to C.sub.20
alpha-olefin (e.g., the polyolefin may be derived from at least one
of ethylene, propylene, butylene, hexene, and/or octene). In
exemplary embodiments, the polyolefin may be an ethylene based
polymer and/or a propylene based polymer
[0015] As used herein, by polymer it meant a compound prepared by
polymerizing monomers, whether of the same or a different type.
Thus, the term polymer embraces the term homopolymer, usually
employed to refer to polymers prepared from only one type of
monomer, and the term interpolymer. It also embraces all forms of
interpolymers, e.g., random, block, homogeneous, heterogeneous,
etc. By copolymer/interpolymer it is meant a polymer prepared by
the polymerization of at least two different types of monomers.
These terms include both classical copolymers, i.e., polymers
prepared from two different types of monomers, and polymers
prepared from more than two different types of monomers, e.g.,
terpolymers, tetrapolymers, etc.
[0016] By ethylene based polymer it is meant a polymer that
includes a majority weight percent polymerized ethylene monomer
(based on the total weight of polymerizable monomers), and
optionally may comprise at least one polymerized comonomer
different from ethylene (such as at least one selected from a
C.sub.3 to C.sub.20 alpha-olefin) so as to form an ethylene-based
interpolymer. For example, when the ethylene-based polymer is an
ethylene-propylene copolymer, the amount of ethylene may be greater
than 50 wt %, based on the total weight to the copolymer. "Units
derived from ethylene" and like terms mean the units of a polymer
that formed from the polymerization ethylene monomers.
[0017] By propylene based polymer it is meant a polymer that
includes a majority weight percent polymerized propylene monomer
(based on the total weight of polymerizable monomers), and
optionally may comprise at least one polymerized comonomer
different from propylene (such as at least one selected from a
C.sub.2 and C.sub.4 to C.sub.20 alpha-olefin) so as to form an
propylene-based interpolymer. For example, when the propylene-based
polymer is a propylene-ethylene copolymer, the amount of propylene
may be greater than 50 wt %, based on the total weight to the
copolymer. "Units derived from propylene" and like terms mean the
units of a polymer that formed from the polymerization propylene
monomers.
[0018] Exemplary aqueous acid polymer dispersion may include
ethylene-acrylic acid interpolymers, ethylene-methacrylic acid
interpolymers, and/or ethylene-crotonic acid interpolymers. The
ethylene-acrylic acid interpolymer is prepared by the
copolymerization of at least ethylene and acrylic acid. The
ethylene-methacrylic acid interpolymer is prepared by
copolymerization of at least ethylene and methacrylic acid. The
ethylene-crotonic acid interpolymer is prepared by copolymerization
of at least ethylene and crotonic acid. It is understood that in
such an aqueous acid polymer dispersion, exemplary embodiments are
not limited to just ethylene-acrylic acid interpolymers,
ethylene-methacrylic acid interpolymers, and/or ethylene-crotonic
acid interpolymers. For example, ethylene can be copolymerized with
more than one of the following: acrylic acid, methacrylic acid,
and/or crotonic acid.
[0019] Exemplary aqueous acid polymer dispersions may include at
least one ethylene-acrylic acid (EAA) copolymer (and/or
ethylene-methacrylic acid copolymer) as the base polymer that is
dispersed in the fluid medium (in this case water). The dispersion
may be enabled by BLUEWAVE.TM. Technology, which is a proprietary
and patented mechanical-dispersion technology that is a trademark
of The Dow Chemical Company or an affiliated company of The Dow
Chemical Company. For example, the EAA may be prepared by
copolymerization of ethylene with acrylic acid, which yields
ethylene-acrylic acid EAA copolymers. The ethylene-acrylic acid
copolymer may have an acrylic acid content of at least 10 wt %
(e.g., from 10 wt % to 70 wt %, from 10 wt % to 60 wt %, from 10 wt
% to 50 wt %, from 10 wt % to 40 wt %, from 10 wt % to 30 wt %,
and/or from 15 wt % to 25 wt %). Exemplary EAA copolymers are
available as PRIMACOR.TM. products, available from THE DOW CHEMICAL
COMPANY. The EAA copolymer may have a melt index from 100 to 2000
g/10 minute (ASTM Method D-1238 at 190.degree. C. and 2.16 kg). The
EAA copolymer may have a Brookfield viscosity from 5,000 to 13,000
cps at 350.degree. F., and is available from The Dow Chemical
Company.
[0020] The ethylene-methacrylic acid copolymer may be prepared by
copolymerization of ethylene with methacrylic acid. Exemplary,
ethylene-acrylic acid, ethylene-methacrylic acid, and/or
ethylene-crotonic acid copolymers are discussed in U.S. Pat. Nos.
4,599,392 and/or 4,988,781.
[0021] Exemplary aqueous acid-modified polyolefin polymer
dispersions include dispersions sold as HYPOD.TM. products,
available from The Dow Chemical Company. The HYPOD.TM. products may
be enabled by BLUEWAVE.TM. Technology, which is a proprietary and
patented mechanical-dispersion technology that is a trademark of
The Dow Chemical Company or an affiliated company of The Dow
Chemical Company. BLUEWAVE.TM. Technology may utilize a high-shear
mechanical process that may work by taking traditional
thermoplastic polymers and elastomers and breaking them up into
submicron particles. The aqueous acid-modified polymer dispersions
may include propylene based dispersions and ethylene-based
dispersions, which may combine the performance of
high-molecular-weight thermoplastics and elastomers with the
application advantages of a high-solids waterborne dispersion. The
polyolefin of the dispersion may be a metallocene catalyzed
polyolefin. Exemplary polyolefins are sold in the AFFINITY.TM.,
ENGAGE.TM., VERSIFY.TM., and INFUSE.TM. products, available from
The Dow Chemical Company.
[0022] The aqueous polymer dispersion may be prepared by using a
neutralizing agent. Exemplary neutralizing agents include ammonia,
ammonium hydroxide, potassium hydroxide, sodium hydroxide, lithium
hydroxide, and combinations thereof. For example, if a polar group
of the base polymer is acidic or basic in nature, the polymer may
be partially or fully neutralized with a neutralizing agent to form
a corresponding salt. With the acid polymer modified dispersion
prepared using EAA is used, the neutralizing agent is a base, such
as ammonium hydroxide, potassium hydroxide, and/or sodium
hydroxide. Those having ordinary skill in the art will appreciate
that the selection of an appropriate neutralizing agent may depend
on the specific composition formulated, and that such a choice is
within the knowledge of those of ordinary skill in the art.
[0023] The aqueous polymer dispersion may be prepared in an
extrusion process, e.g., as discussed in U.S. Pat. No. 8,318,257.
FIG. 1 illustrates an exemplary a schematic diagram of an extrusion
apparatus for manufacturing an aqueous polymer dispersions. An
extruder 1 (such as a twin screw extruder) may be coupled to a
pressure control device 2 (such as a pressure control valve, a back
pressure regulator, a melt pump, and/or a gear pump). A
neutralizing agent reservoir 3 and an initial water reservoir 4,
each of which includes a pump (not shown), may be provided in
connection with the extruder 1. The desired amounts of neutralizing
agent and initial water are provided from the neutralizing agent
reservoir 3 and the initial water reservoir 4, respectively. Any
suitable pump may be used, e.g., based on the desired flow. The
neutralizing agent and initial water may be preheated in a
preheater.
[0024] Polymer resin (such as an acid polymer and/or a polyolefin
polymer) may be fed from the feeder 7 to an inlet 8 of the extruder
1, where the resin is melted or compounded. The polymer resin may
be provided in the form of pellets, powder, and/or flakes, for
example. A dispersing agent may be added to the extruder through
and along with the polymer resin or may be provided separately to
the extruder 1. For example, the polymer (and dispersing agent if
included) may be melted, mixed, and conveyed by screws in a mix and
convey zone. The polymer resin melt is then delivered from the mix
and convey zone to an emulsification zone of the extruder where the
initial amounts of water and neutralizing agent (from the
reservoirs 3 and 4) are added through an inlet 5. The resultant
emulsified mixture may be further diluted at least one time using
an additional water via inlet 9 from reservoir 6 in a dilution and
cooling zone of the extruder 1. As would be understood by a person
of ordinary skill in the art, at least in view of U.S. Pat. No.
8,318,257, the dilution scheme of the resultant emulsified mixture
may be varied (e.g., based on the desired solids content). For
example, the emulsified mixture may be further diluted with
additional dispersion medium from additional reservoirs in a
dilution zone of the extruder 1. The dispersion may be diluted to
at least 30 weight percent dispersion in the dilution zone.
[0025] With respect to the screws in the mix and convey zone, one
or more rotating restriction orifices may be located along the
screw. The rotating restriction orifice may improve stability of
the dispersion forming process. Non-rotating restriction orifices
may be used. The screws may include high-mixing kneading disks, in
some embodiments. In addition to the high-mixing kneading disks 60
described above and optionally low free volume kneading disks 62,
which may minimize the volume weighted particle size distribution
of dispersions formed using the extruder 1.
[0026] The extruder 1 includes high internal phase emulsion
creation (HIPE) zones along a length thereof, e.g., as discussed in
U.S. Pat. No. 8,318,257. For example, the aqueous polymer
dispersion may be prepared using a system that incorporates 12 HIPE
zones, in which the temperature is varied in the zones. Depending
upon the feed composition (such as the polymer, dispersing agent,
neutralizing agent, etc.), it may be desirable to have a longer or
a shorter HIPE zones. Multiple dispersion medium injection points
may be provided to allow the HIPE zones to be extended or shortened
as needed. As the particle size of the dispersed polymer particles
is formed in the HIPE zone, adequate mixing should be provided to
develop the desired particle size. Having a variable length for the
HIPE zone may allow for a broader range of polymers to be processed
in a single extruder, providing for process flexibility, among
other benefits.
[0027] The twin screw extruder barrels, screws, and dilution medium
injection points may be varied such that the length to diameter
(L/D) of the HIPE zone is at least 16 when producing EEA containing
dispersions. The apparatuses described above may be used to produce
dispersions, where, in some embodiments, the polymer feed rate may
range from about 50 to about 2000 lb/h (about 22 to about 907
kg/h). In other embodiments, the polymer feed rate may range from
about 100 to about 1000 lb/h (between about 45 and about 454 kg/h).
In other embodiments, the screw speed may range from about 300 rpm
to about 1200 rpm. In yet other embodiments, the extruder discharge
pressure may be maintained at a pressure ranging from about 300 to
about 800 psig (from about 21 bar to about 56 bar).
Polyol Component
[0028] The polyol component includes at least one polyether polyol
and/or polyester polyol. Exemplary polyether polyols are the
reaction product of alkylene oxides (such as at least one ethylene
oxide, propylene oxide, and/or butylene oxide) with initiators
containing from 2 to 8 active hydrogen atoms per molecule.
Exemplary initiators include ethylene glycol, diethylene glycol,
propylene glycol, dipropylene glycol, butane diol, glycerol,
trimethylolpropane, triethanolamine, pentaerythritol, sorbitol,
ethylene diamine, toluene diamine, diaminodiphenylmethane,
polymethylene polyphenylene polyamines, ethanolamine,
diethanolamine, and mixtures of such initiators. Exemplary polyols
include VORANOL.TM. products, available from The Dow Chemical
Company. The polyol component may include polyols that are useable
to form viscoelastic polyurethane foams.
[0029] For example, the polyol component may include a
polyoxyethylene-polyoxypropylene polyether polyol that has an
ethylene oxide content of at least 50 wt %, that has a nominal
hydroxyl functionality from 2 to 6 (e.g., 2 to 4), and has a number
average molecular weight from 500 g/mol to 5000 g/mol (e.g., 500
g/mol to 4000 g/mol, from 600 g/mol to 3000 g/mol, 600 g/mol to
2000 g/mol, 700 g/mol to 1500 g/mol, and/or 800 g/mol to 1200
g/mol). The polyoxyethylene-polyoxypropylene polyether polyol that
has an ethylene oxide content of at least 50 wt % may account for 5
wt % to 90 wt % (e.g., 10 wt % to 90 wt %, 35 wt % to 90 wt %, 40
wt % to 85 wt %, 50 wt % to 85 wt %, 50 wt % to 80 wt %, and/or 55
wt % to 70 wt %) of the isocyanate-reactive component. The
polyoxyethylene-polyoxypropylene polyether polyol that has an
ethylene oxide content of at least 50 wt % may be the majority
component in the isocyanate-reactive component.
[0030] The polyol component may include a
polyoxypropylene-polyoxyethylene polyether polyol that has an
ethylene oxide content of less than 20 wt % that has a nominal
hydroxyl functionality from 2 to 6 (e.g., 2 to 4) and has a number
average molecular weight greater than 1000 g/mol (or greater than
1500 g/mol) and less than 6000 g/mol. For example, the molecular
weight may be from 1500 g/mol to 5000 g/mol, 1600 g/mol to 5000
g/mol, 2000 g/mol to 4000 g/mol, and/or 2500 g/mol to 3500 g/mol.
The polyoxypropylene-polyoxyethylene polyether polyol that has an
ethylene oxide content of less than 20 wt % may account for 5 wt %
to 90 wt % (e.g., 5 wt % to 70 wt %, 5 wt % to 50 wt %, 10 wt % to
40 wt %, and/or 10 wt % to 30 wt %) of the isocyanate reactive
component. The polyoxypropylene-polyoxyethylene polyether polyol
that has an ethylene oxide content of less than 20 wt % may be in a
blend with the polyoxypropylene polyether polyol that has an
ethylene oxide content of at least 50 wt %, whereas the latter of
which is included in a greater amount.
[0031] The polyol component may include a polyoxypropylene
polyether polyol that has a nominal hydroxyl functionality from 2
to 6 (e.g., 2 to 4) and has a number average molecular weight from
500 g/mol to 5000 g/mol (e.g., 500 g/mol to 4000 g/mol, from 600
g/mol to 3000 g/mol, 600 g/mol to 2000 g/mol, 700 g/mol to 1500
g/mol, and/or 800 g/mol to 1200 g/mol). The polyoxypropylene
polyether polyol may account for 5 wt % to 90 wt % (e.g., 5 wt % to
70 wt %, 5 wt % to 50 wt %, 10 wt % to 40 wt %, and/or 10 wt % to
30 wt %) of the isocyanate reactive component. The polyoxypropylene
polyether polyol may be in a blend with the polyoxypropylene
polyether polyol that has an ethylene oxide content of at least 50
wt %, whereas the latter of which is included in a greater
amount.
[0032] In an exemplary embodiment, the polyol component may include
a blend of the polyoxyethylene-polyoxypropylene polyether polyol
that has an ethylene oxide content of at least 50 wt %, the
polyoxyethylene-polyoxypropylene polyether polyol that has an
ethylene oxide content of less than 20 wt %, and the
polyoxypropylene polyether polyol.
[0033] The polyol component may be mixed with the preformed aqueous
polymer dispersion (and optionally at least part of the additive
component) before contacting the isocyanate component.
Additive Component
[0034] The additive component is separate from the components that
form the preformed aqueous dispersion and the polyol component. The
additive component is part of the isocyanate-reactive component,
but other additives may be incorporated into the isocyanate
component. The additive component may include a catalyst, a curing
agent, a crosslinker, a surfactant, a blowing agent (aqueous and
non-aqueous, separate from the aqueous polymer dispersion), a
polyamine, a plasticizer, a fragrance, a pigment, an antioxidant, a
UV stabilizer, water (separate from the aqueous polymer
dispersion), and/or a filler. Other exemplary additives include a
chain extender, flame retardant, smoke suppressant, drying agent,
talc, powder, mold release agent, rubber polymer ("gel") particles,
and other additives that are known in the art for use in
viscoelastic foams and viscoelastic foam products.
[0035] The additive component may include tin catalyst, zinc
catalyst, bismuth catalyst, and/or amine catalyst. The total amount
of catalyst in the isocyanate-reactive component may be from 0.1 wt
% to 3.0 wt %.
[0036] A surfactant may be included in the additive component,
e.g., to help stabilize the foam as it expands and cures. Examples
of surfactants include nonionic surfactants and wetting agents such
as those prepared by the sequential addition of propylene oxide and
then ethylene oxide to propylene glycol, solid or liquid
organosilicones, and polyethylene glycol ethers of long chain
alcohols. Ionic surfactants such as tertiary amine or alkanolamine
salts of long chain alkyl acid sulfate esters, alkyl sulfonic
esters, and alkyl arylsulfonic acids may be used. For example, the
formulation may include a surfactant such as an organosilicone
surfactant. The total amount of an organosilicone surfactant in the
isocyanate-reactive component may be from 0.1 wt % to 5.0 wt %, 0.1
wt % to 3.0 wt %, 0.1 wt % to 2.0 wt %, and/or 0.1 wt % to 1.0 wt
%.
[0037] The additive component may include water, which is separate
from the preformed aqueous polymer dispersion. The water may
account for less than 2.0 wt % of the total weight of
isocyanate-reactive component. The total water, including water
from the preformed aqueous polymer dispersion and water from the
additive component, may account for less than 5 wt % of the total
weight of isocyanate-reactive component.
[0038] The additive component may exclude any conventional
polyurethane foam chemical cell openers based on the use of the
aqueous polymer dispersion. The additive component may exclude
polybutene, polybutadiene, and waxy aliphatic hydrocarbons such as
oils (e.g., mineral oil, paraffin oil, and/or naphthenic oil) that
are commonly employed cell openers in low resiliency foams. The
additive component may exclude cell openers that are polyols
derived primarily from alkoxylation of .alpha.,.beta.-alkylene
oxides having at least 4 carbon atoms, e.g., as discussed U.S. Pat.
No. 4,596,665. The additive component may exclude cell openers that
are polyethers of up to about 3500 molecular weight that contain a
high proportion (usually 50 percent or higher) of units derived
from ethylene oxide or butylene oxide, e.g., as discussed in the
background section of U.S. Pat. No. 4,863,976. The additive
component may exclude cell openers that are polyether polyols
having a molecular weight of at least 5000 and having at least 50
wt % of oxyethylene units, e.g., as discussed in the claims of U.S.
Pat. No. 4,863,976.
Isocyanate Component
[0039] The isocyanate component includes at least one isocyanate.
The isocyanate component is present at an isocyanate index from 50
to 110 (e.g., from 60 to 100, from 65 to 100, from 70 to 100, from
74 to 100, from 70 to 90, from 70 to 85, and/or from 74 to 85). The
isocyanate index is defined as the molar stoichiometric excess of
isocyanate moieties in a reaction mixture with respect to the
number of moles of isocyanate-reactive units (active hydrogens
available for reaction with the isocyanate moiety), multiplied by
100. An isocyanate index of 100 means that there is no
stoichiometric excess, such that there is 1.0 mole of isocyanate
groups per 1.0 mole of isocyanate-reactive groups, multiplied by
100.
[0040] The isocyanate component may include one or more isocyanate
such as polyisocyanate and/or isocyanate-terminated prepolymer. The
isocyanate may be isocyanate-containing reactants that are
aliphatic, cycloaliphatic, alicyclic, arylaliphatic, and/or
aromatic polyisocyanates or derivatives thereof. Exemplary
derivatives include allophanate, biuret, and NCO (isocyanate
moiety) terminated prepolymer. For example, the isocyanate
component may include at least one aromatic isocyanate, e.g., at
least one aromatic polyisocyanate or at least one
isocyanate-terminated prepolymer derived from an aromatic
polyisocyanate. The isocyanate component may include at least one
isomer of toluene diisocyanate (TDI), crude TDI, at least one
isomer of diphenyl methylene diisocyanate (MDI), crude MDI, and/or
higher functional methylene polyphenyl polyisocyanate. Examples
include TDI in the form of its 2,4 and 2,6-isomers and mixtures
thereof and MDI in the form of its 2,4'-, 2,2'- and 4,4'-isomers
and mixtures thereof. The mixtures of MDI and oligomers thereof may
be crude or polymeric MDI and/or a known variant of MDI comprising
urethane, allophanate, urea, biuret, carbodiimide, uretonimine
and/or isocyanurate groups. Exemplary isocyanates include
VORANATE.TM. M 220 (a polymeric methylene diphenyl diisocyanate
available from The Dow Chemical Company). Other exemplary
polyisocyanate include tolylene diisocyanate (TDI), isophorone
diisocyanate (IPDI) and xylene diisocyanates (XDI), and
modifications thereof.
Viscoelastic Foam
[0041] The viscoelastic polyurethane foam may be useful in a
variety of packaging applications, comfort applications (such as
mattresses--including mattress toppers, pillows, furniture, seat
cushions, etc.) shock absorber applications (such as bumper pads,
sport and medical equipment, helmet liners, etc.), and noise and/or
vibration dampening applications (such as earplugs, automobile
panels, etc.).
[0042] The viscoelastic polyurethane foam may be prepared in a
slabstock process (e.g., as free rise foam), a molding process
(such as in a box foaming process), or any other process known in
the art. In a slabstock process, the components may be mixed and
poured into a trough or other region where the formulation reacts,
expands freely in at least one direction, and cures. Slabstock
processes are generally operated continuously at commercial scales.
In a molding process, the components may be mixed and poured into a
mold/box (heated or non-heated) where the formulation reacts,
expands without the mold in at least one direction, and cures.
[0043] The viscoelastic polyurethane foam may be prepared at
initial ambient conditions (i.e., room temperature ranging from
20.degree. C. to 25.degree. C. and standard atmospheric pressure of
approximately 1 atm). For example, the viscoelastic polyurethane
foam may include an acid polymer and/or an acid-modified polyolefin
polymer (e.g., a polymer that has a melting point above 100.degree.
C.) without requiring heating or application of pressure to the
isocyanate-reactive component. Foaming at pressure below
atmospheric condition can also be done, to reduce foam density and
soften the foam. Foaming at pressure above atmospheric condition
can be done, to increase foam density and therefore the foam load
bearing as measured by indentation force deflection (IFD). In a
molding processing, the viscoelastic polyurethane foam may be
prepared at initial mold temperature above ambient condition, e.g.,
50.degree. C. and above. Overpacking of mold, i.e. filling the mold
with extra foaming material, can be done to increase foam
density.
[0044] The calculated total water content for the reaction system
used to form the viscoelastic foam may be less than 5 wt %, less
than 3 wt %, less than 2.0 wt %, and/or less than 1.6 wt %, based
on the total weight of the reaction system for forming the
viscoelastic polyurethane foam. The calculated total water content
is calculated as the total amount of DI (deionized water) added to
the formulation plus the amount of water added to the formulation
as part of the preformed aqueous polymer dispersion. For example,
the calculated total water content may be from 0.5 wt % to 1.6 wt
%, 0.5 wt % to 1.5 wt %, and/or 1.0 wt % to 1.5 wt %.
[0045] The resultant viscoelastic polyurethane foam may exhibit
improved wicking effect and/or improved moisture/heat management.
With respect to moisture and heat management of a resultant foam,
e.g., with respect to a viscoelastic polyurethane foam mattress or
pillow, a good wicking effect may enable sweat to move quickly away
from a user's skin. The key aspects of human body to maintain the
comfort temperature are through moisture vapor by sweating.
Sweating is the body's mechanism of keeping us cool. Good wicking
effect may enable the user to remain dry and cool so as providing
increased comfort. The good wicking effect may also provide the
sweat/water with more surface area to evaporate from. Said in
another way, as the sweat/water is dispersed over a greater area it
may evaporate more rapidly than when the water is pooled together
over a small surface area. Further, good moisture permeability may
enable moisture to leave a user's skin and enable natural moisture
vapor to bring heat away from the user's skin.
[0046] For example, the viscoelastic polyurethane foam may exhibit
a visually observable wicking height (e.g., on a sample of the
viscoelastic polyurethane foam having the dimensions of 1.0
inch.times.0.5 inch.times.2.0 inch, when an edge of the sample is
submersed in 5.0 mm of dyed water) that is greater than a visually
observable wicking height of a sample of a different viscoelastic
polyurethane foam (which sample has the same dimensions) that is
prepared using the same isocyanate-component, the same calculated
total water content, and the same isocyanate-reactive component,
except that the preformed aqueous polymer dispersion is excluded.
For example, the wicking height may be greater by a factor of at
least 3 (e.g., may be 3 to 10 times greater and/or 3.5 to 5.5 times
greater).
[0047] The viscoelastic polyurethane foam may exhibit a visually
observed wicking time (using a sample of the viscoelastic
polyurethane foam), when three drops of dyed water are placed on a
surface of the sample, that is less than a visually observed
wicking time using a sample of a different viscoelastic
polyurethane foam that is prepared using the same
isocyanate-component, the same calculated total water content, and
the same isocyanate-reactive component, except that the preformed
aqueous polymer dispersion is excluded. As would be understanding,
the compared samples may have a same thickness/depth, but the
length and width of the samples are not dependent on the results.
The wicking time is visually observed as the time at which it takes
for three drops of dyed water to disappear (i.e., be absorbed by
the foam) away from the surface of the samples. The wicking time
may be decreased by at least 30 seconds so as to be significantly
quicker when the preformed aqueous polymer dispersion is used. For
example, the wicking time may be less than 5 seconds for the
polyurethane foam prepared using the preformed aqueous polymer
dispersion (e.g., greater than half a second).
[0048] The viscoelastic polyurethane foam may exhibit improved
water vapor permeability, e.g., as measured according to ASTM
E96/E96M (and optionally in view of ASTM E2321-03). For example,
the water vapor permeability may be improved by at least 5% (e.g.,
from 5% to 20%) for the polyurethane foam prepared using the
preformed aqueous polymer dispersion.
[0049] As would be understood by a person of ordinary skill in the
art, the above comparison of two different foams refers to foams
prepared using the same process conditions, same equipment, and the
same formulations, except for the exclusion of the preformed
aqueous polymer dispersion and the increased water content so as to
account for excluding the preformed aqueous polymer dispersion in
the comparative example.
[0050] All parts and percentages are by weight unless otherwise
indicated. All molecular weight data is based on number average
molecular weight, unless indicated otherwise.
EXAMPLES
[0051] The data and descriptive information provided herein are
based on approximations. Further, the materials principally used
are as the following:
[0052] AD 1 [0053] An aqueous acid polymer dispersion including
approximately 21.7 wt % of a potassium hydroxide neutralized
ethylene-acrylic acid copolymer salt and 78.3 wt % of water, made
using a twin screw extruder and a dilution scheme as described in
U.S. Pat. No. 8,318,257, is prepared as follows: [0054] A first
feed includes 100 wt % of PRIMACOR.TM. 5986 (an ethylene acrylic
acid resin having approximately 20.5 wt % of acrylic acid) at a
flow rate of 234 lb/h, a second feed includes 100 wt % of potassium
hydroxide at a flow rate of 125 lb/h, and a third feed includes 100
wt % of water at a flow rate of 50 lb/h. A first dilution pump
feeds water at 220 lb/h and a second dilution pump at 538 lb/h to
achieve the desired solids content. The barrel/zone temperature
control conditions are the following:
TABLE-US-00001 [0054] TABLE 1 Zone Number Temperature .degree. C.
Zone 1 27 Zone 2 151 Zone 3 147 Zone 4 148 Zone 5 161 Zone 6 149
Zone 7 107 Zone 8 109 Zone 9 80 Zone 10 131 Zone 11 72 Zone 12
72
[0055] AD 2 [0056] An aqueous acid polymer dispersion of
approximately 32.3 wt % of an ammonium hydroxide neutralized
ethylene acrylic acid copolymer salt and 67.7 wt % of water,
prepared similar to as AD 1 except, the second feed is different
and the dilution scheme is varied to achieve the desired higher
solids content, as would be understood by one of ordinary skill in
the art.
[0057] AD 3 [0058] An aqueous dispersion of an aqueous
acid-modified ethylene based copolymer, at a solids content from
40.5 wt % to 43.5 wt %, based on the total weight of the aqueous
dispersion (available as HYPOD.TM. 8503 from The Dow Chemical
Company and enabled with BLUEWAVE.TM. Technology).
[0059] AD 4 [0060] An aqueous dispersion of an aqueous
acid-modified polyolefin polymer, at a solids content from 54 wt %
to 58 wt %, based on the total weight of the aqueous dispersion
(available as HYPOD.TM. XU-36534 from The Dow Chemical Company and
enabled with BLUEWAVE.TM. Technology).
[0061] Polyol 1 [0062] A polyoxypropylene polyether polyol, having
a nominal hydroxyl functionality of 3 and a number average
molecular weight of approximately 1000 g/mol (available as
VORANOL.TM. 3150 from The Dow Chemical Company).
[0063] Polyol 2 [0064] A glycerine initiated
polyoxyethylene-polyoxypropylene polyether polyol, having an
ethylene oxide content of approximately 60 wt %, a nominal hydroxyl
functionality of 3, primary hydroxyl content of approximately 35%,
and a number average molecular weight of approximately 1000
g/mol.
[0065] Polyol 3 [0066] An polyoxypropylene-polyoxyethylene
polyether polyol initiated with glycerine, having an ethylene oxide
content of less than 20 wt %, a nominal hydroxyl functionality of
3, and a number average molecular weight of approximately 3100
g/mol (available as VORANOL.TM. 3136 from The Dow Chemical
Company).
[0067] Isocyanate [0068] A polymeric methylene diphenyl
diisocyanate--PMDI (available as PAPI.TM. 94 from The Dow Chemical
Company).
[0069] Surfactant [0070] An organosilicone surfactant (available as
Niax.TM. L-618 from Momentive Performance Materials).
[0071] Amine 1 [0072] A tertiary amine catalyst (available
Dabco.RTM. BL-11 from Air Products).
[0073] Amine 2 [0074] A tertiary amine catalyst (available as
Dabco.RTM. 33-LV from Air Products).
[0075] Tin [0076] A tin catalyst (available as KOSMOS.RTM. 29 from
Evonik Industries).
[0077] DI [0078] Deionized Water.
[0079] Working Examples 1 to 3 and Comparative Examples A and B are
prepared according to the approximate formulations in Table 2,
below. In the Examples below, the total formulation mass is set to
be 1900 grams. Working Examples 1 to 3 are prepared using one of AD
1 and AD 2, which are preformed aqueous acid dispersions.
Comparative Example A is prepared using only water, i.e., not using
a dispersion. Comparative Example B is an attempt at preparing a
viscoelastic foam using ethylene-acrylic acid copolymer and water
that are added separately, i.e., not using a preformed dispersion.
However, due to the inability of ethylene-acrylic acid copolymer to
dissolve in water at ambient conditions (it is believed, without
intending to be bound by this theory, that a temperature of at
least approximately 120.degree. C. would be needed to melt the
ethylene-acrylic acid copolymer crystals in water) such a mixture
would be non-preferred and/or unsuitable for use in a foaming
reaction for forming a viscoelastic foam. In other words, it is
believed, the high temperature required to obtain solubility would
be non-preferred and/or unsuitable for the purpose herein and/or
non-dissolved ethylene-acrylic acid copolymer crystals would be
non-preferred and/or unsuitable for the purpose herein. The density
of the samples range from approximately 2.7 to 3.0 lb/ft.sup.3
(according to ASTM D 3574).
TABLE-US-00002 TABLE 2 Ex. 1 Ex. 2 Ex. 3 Ex. A Ex. B
Isocyanate-Reactive Component (amount based on parts by weight) AD
1 1.40 1.40 -- -- -- AD 2 -- -- 1.62 -- -- PRIMACOR .TM. -- -- --
-- 1.40 5986 DI 1.10 1.10 1.10 2.20 2.20 Polyol 1 20.00 20.00 20.00
20.00 20.00 Polyol 2 60.00 60.00 60.00 60.00 60.00 Polyol 3 20.00
20.00 20.00 20.00 20.00 Surfactant 0.80 0.80 0.80 0.80 0.80 Amine 1
0.15 0.15 0.15 0.15 0.15 Amine 2 0.05 0.05 0.05 0.05 0.05 Tin 0.05
0.05 0.05 0.05 0.05 Isocyanate Component (amount based on parts by
weight) Isocyanate 53.35 52.01 53.35 53.35 53.35 Composition
Properties Approximate 156 156 157 156 156 Total Parts Index 80 78
80 80 80 AD wt % in 1.35 1.35 1.56 -- -- Isocyanate- Reactive
Component Calculated 2.20 2.20 2.20 2.20 2.20 Total Water Content
(parts by weight) Foam Properties Air Flow (scfm) 8.5 8.4 7.9 3.4 *
Average 5.2 -- 4 4 * Resiliency (%) Recovery Time 3 5 3 3 *
(seconds) IFD @ 25% 8.2 9.9 7.8 14.0 * Deflection (lb) IFD @ 65%
17.6 21.1 16.1 28.3 * Deflection (lb) IFD @ 25% 7.1 8.3 6.9 12.5 *
Return (lb) *Unable to form a viscoelastic foam because the
PRIMACOR .TM. 5986 did not dissolve in water at ambient
conditions.
[0080] Working Examples 4 to 11 and Comparative Example C are
prepared according to the approximate formulations in Table 3,
below. In the Examples below, the total formulation mass is set to
be 1900 grams. Working Examples 4 to 11 are prepared using one of
AD 3 and AD 4, which are preformed aqueous acid-modified polyolefin
dispersion. Comparative Example C is prepared using only water,
i.e., not using a dispersion. The density of the samples range from
approximately 2.5 to 3.0 lb/ft.sup.3 (according to ASTM D
3574).
TABLE-US-00003 TABLE 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7 Ex. 8 Ex. 9 Ex. 10
Ex. 11 Ex. 12 Ex. C Isocyanate-Reactive Component (amount based on
parts by weight) AD 3 2.20 0.77 0.77 1.91 -- -- -- -- 1.91 -- AD 4
-- -- -- -- 0.51 1.01 1.52 2.53 -- -- DI 1.10 1.98 1.76 1.10 1.98
1.76 1.54 1.10 1.10 2.20 Polyol 1 15.00 15.00 15.00 15.00 15.00
15.00 15.00 15.00 20.00 15.00 Polyol 2 60.00 60.00 60.00 60.00
60.00 60.00 60.00 60.00 60.00 60.00 Polyol 3 25.00 25.00 25.00
25.00 25.00 25.00 25.00 25.00 20.00 25.00 Surfactant 0.80 0.80 0.80
0.80 0.80 0.80 0.80 0.80 0.80 0.80 Amine 1 0.15 0.15 0.15 0.15 0.15
0.15 0.15 0.15 0.15 0.15 Amine 2 0.05 0.05 0.05 0.05 0.05 0.05 0.05
0.05 0.05 0.05 Tin 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05
0.05 Isocyanate Component (amount based on parts by weight)
Isocyanate 51.00 50.99 50.99 50.99 50.99 50.99 50.99 50.99 51.48
50.99 Composition Properties Approximate 155 154 155 155 155 155
155 155 156 154 Total Parts Index 75 78 78 78 78 78 78 78 77 78 AD
wt % in 2.11 0.74 0.74 1.84 0.50 0.97 1.46 2.42 1.84 -- Isocyanate
Reactive Component Calculated 2.37 2.20 2.20 2.20 2.20 2.20 2.20
2.20 2.20 2.20 Total Water Content (parts by weight total) Foam
Properties Air Flow 8.9 5.6 6.2 9.7 5.4 6.1 7.3 9.6 7.3 4.1 (scfm)
Average 6 4 4 5 3 4 4 4 5 3 Resiliency (%) Recovery Time 7 3 3 5 3
4 4 4 2 3 (seconds) IFD @ 25% 5.2 8.4 8.3 5.9 8.8 8.8 7.9 5.8 11.4
10.7 Deflection (lb) IFD @ 65% 11.6 18.6 18.4 13.2 19.1 19.2 17.3
13.2 25.9 22.6 Deflection (lb) IFD @ 25% 4.2 7.3 7.2 4.9 7.8 7.5
6.7 5.0 10.2 9.4 Return (lb)
[0081] For each of Working Examples 1 to 11 land Comparative
Examples A to C, foam samples are prepared by box foaming at
ambient conditions, under a fume hood using a 38 cm.times.38
cm.times.24 cm (15''.times.15''.times.9.5'') wooden box lined with
clear plastic film. A 16-pin (4 pins each in four radial directions
that are separated by 90.degree.) mixer at high rotation speed is
used at high rotation speed setting, together with a 1 gallon cup
(16.5 cm diameter, 18 cm tall). The components in the
Isocyanate-Reactive Component, with the exception of the Tin
catalyst, are mixed first for 15 seconds at 2400 rpm. Then, the Tin
catalyst is added and immediately mixed for another 15 seconds at
2400 rpm. Next, the Isocyanate Component is added and immediately
mixed for another 3 seconds at 3000 rpm. Then, the mixed
Isocyanate-Reactive Component and Isocyanate Component is poured
into the box lined with plastic film. The foam is observed as
having reached maximum height when bubbles appear at the top
surface of the foam. Once foaming is complete, the foam is further
allowed to cure overnight under the fume hood. Foam sample walls
are discarded, and the remaining samples are characterized.
[0082] For Working Example 12, the foam is made using a Cannon
Varimax foaming machine. The Polyol 1 and Polyol 3 are used as a
blend with a ratio of 1:1. The total polyol flow rate targets 110
lb/min. A foam bun is made with the size of approximately 96
inch.times.52 inch.times.20 inch. The resultant foam sample is cut
a day after the foam is fabricated. Then, the samples are
conditioned for 24 hours before the physical property tests are
performed.
[0083] Calculated Total Water Content (parts by weight) is
calculated as the total amount of DI (deionized water) added to the
formulation plus the amount of water added to the formulation as
part of the aqueous dispersion.
[0084] Air flow is a measure of the air that is able to pass
through the foam under a given applied air pressure. Air flow is
measured as the volume of air which passes through a 1.0 inch (2.54
cm) thick.times.2 inch.times.2 inch (5.08 cm) square section of
foam at 125 Pa (0.018 psi) of pressure. Units are expressed in
standard cubic feet per minute (scfm). A representative commercial
unit for measuring air flow is manufactured by TexTest AG of
Zurich, Switzerland and identified as TexTest Fx3300. Herein, air
flow is measured according to ASTM D 3574.
[0085] Average resiliency is measured according to ASTM D 3574, in
particular using the ball rebound test. Recovery time is measured
is measured by releasing/returning the compression load head from a
75% position (i.e., the foam sample is compressed to 100% minus 75%
of the sample's original thickness) to the position where foam
compression is to a 10% position (based on the original thickness
of the foam sample). The Recovery Time is defined as the time from
the releasing/returning the compression load head to the moment
that the foam pushes back against the load head with a force of at
least 1 newton.
[0086] IFD is referred to as indentation force deflection and it is
measured according to ASTM D 3574. IFD is defined as the amount of
force in pounds required to indent a fifty square inch circular
plate sample a certain percentage of the sample's original
thickness. Herein, IFD is specified as the number of pounds at 25%
deflection and at 65% deflection for the foam sample. Lower IFD
values are sought for viscoelastic foams. For example, an IFD at
25% from 6 to 12 may be used for bed pillows, thick back pillows,
etc. An IFD at 25% from 12 to 18 may be used for medium thickness
back pillows, upholstery padding, etc. An IFD at 25% from 18 to 24
may be used for thin back pillows, tufting matrix, very thick seat
cushions, etc. An IFD at 25% greater than 24 may be used for
average to firmer seat cushions, firm mattresses, shock absorbing
foams, packaging foams, carpet pads, and other uses requiring
ultra-firm foams.
[0087] IFD at 25% Return is the ability of the foam to recover. In
particular, the IFD at 25% Return is measured as the percentage of
the IFD at 25% that is recovered after cycling through the IFD at
65% measurement and returning to 25% compression.
[0088] As used herein, the term "tear strength" is used herein to
refer to the maximum average force required to tear a foam sample
which is pre-notched with a slit cut lengthwise into the foam
sample. The test results are determined according to the procedures
of ASTM D3574-F in pound-force per linear inch (lbf/in) or in
Newtons per meter (N/m).
Wicking Effect and Moisture/Heat Management
[0089] Working Example 12 is further evaluated for wicking and
moisture/heat management, as combined with the high airflow. To
test the wicking wetting effect, Comparative Example D is prepared
using the same method and formulation as Working Example 12, except
Additive 3 is not added to the formulation.
[0090] To realize a good wicking effect, the materials should have
a good wetting effect. FIG. 2 illustrates the wetting effect on the
foam sample of Working Example 12 and FIG. 3 illustrates the
wetting effect on the foam sample of Comparative Example D. To
perform the wetting effect, three drops of dyed water are put on
the surface of the respective foam samples having a thickness of
1.0 inch and the time at which it takes for the drops of water to
disappear from the surface is visually observed and recorded as the
wicking time. The water is dyed with an orange dye available from
Milliken Chemical. Working Example 12 is visually observed to have
a faster wicking speed and the water drops are wicked away from the
surface of the sample at a wicking time of approximately 1 second
and Comparative Example D is visually observed to have a slower
wicking speed with a wicking time of 38 seconds. Accordingly, it is
seen that when the foam samples for are made using the same
conditions and formulations, except that the preformed aqueous
polymer dispersion is excluded in the comparative example, that the
wicking speed is quicker and the wicking time is lower by
approximately 37 seconds, when the preformed aqueous polymer
dispersion is included.
[0091] Wicking height may also be testing using a vertical wicking
test. In particular, foam samples having the dimensions of 1.0
inch.times.0.5 inch.times.2.0 inch are prepared for Working Example
12 and Comparative Example D. The tips of the foam samples are
immersed in 5.0 mm of the dyed water, while the foam samples are
maintain in a substantially vertical position relative to the
horizontal dish holding the dyed water. Vertical wicking, i.e.,
upward movement, of the water is enabled for 1 minute (at ambient
conditions). Then, the upward movement is measured using a ruler
and recorded as the vertical wicking height. Working Example 12 is
measured as having a vertical wicking height of 6.35 mm and
Comparative Example D is measured as having a vertical wicking
height of 1.59 mm. Accordingly, it is seen that when the foam
samples are made using the same conditions and formulations, except
that the preformed aqueous polymer dispersion is excluded in the
comparative example, that the wicking height is increased by a
factor of approximately 4 when the preformed aqueous polymer
dispersion is included.
[0092] The water vapor permeability of Working Example 12 and
Comparative Example D may be testing. In particular, a standard cup
desiccant method is conducted following ASTM E96/E96M. Further,
ASTM E2321-03 is followed for the Standard Practice, a petri dish
method (the diameter of the petri dish is 5.5 inch). For testing
each of Working Example 12 and Comparative Example D, three
specimens are used, of which specimens are foam samples that have a
thickness of approximately 1.30 inches and that have their edges
sealed with wax (e.g., wax that is melted at approximately
140.degree. F.). To test the water vapor permeability, the petri
dish is filled up to within 1/4 in of the top rim. During testing
the humidity level is 72.7% and the temperature control is
50.8.degree. F.
[0093] Working Example 12 is observed as having a water vapor
permeability of approximately 71.6
(grains/hour/ft.sup.2)/.DELTA.P.times.inches and Comparative
Example D is observed as having a significantly lower water vapor
permeability of approximately 67.4
(grains/hour/ft.sup.2)/.DELTA.P.times.inches. Accordingly, it is
seen that when the foam samples are made using the same conditions
and formulations, except that the preformed aqueous polymer
dispersion is excluded in the comparative example, that the water
vapor permeability may be improved by approximately 5.9% when the
preformed aqueous polymer dispersion is included.
* * * * *