Note: Descriptions are shown in the official language in which they were submitted.
CA 02709801 2010-06-17
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ROOM TEMPERATURE CROSSLINKED FOAM
TECHNICAL FIELD AND INDUSTRIAL APPLICABILITY OF THE INVENTION
The present invention relates generally to safe foams and, more particularly,
to
foams formed from latex that are used to fill cavities, cracks, and crevasses
to enhance the
sealing and insulating properties of buildings, cars, and appliances and to
form backing for
carpets, cushions, mattresses, pillows, and toys. Methods of making such foams
are also
provided.
BACKGROUND OF THE INVENTION
Spray foams have found widespread utility in the fields of insulation and
structural
reinforcement. For example, spray foams are commonly used to insulate or
impart
structural strength to items such as automobiles, hot tubs, refrigerators,
boats, and building
structures. In addition, spray foams are used in applications such as
cushioning for
furniture and bedding, padding for underlying carpets, acoustic materials,
textile
laminates, and energy absorbing materials. Currently, spray foams, especially
those used
as insulators or sealants for home walls, are polyurethane spray foams.
Polyurethane spray foams and their methods of manufacture are well known.
Typically, polyurethane spray foams are formed from two separate components,
commonly referred to as an "A" side and a "B" side, that react when they come
into
contact with each other. The first component, or the "A" side, contains an
isocyanate such
as a di- or poly- isocyanate that has a high percent of NCO (nitrogen, carbon
and oxygen)
functional groups on the molecule. The second component, or "B" side, contains
nucleophilic reagents such as polyols that include two or more hydroxyl
groups, silicone-
based surfactants, blowing agents, catalysts, and/or other auxiliary agents.
The
nucleophilic reagents are generally polyols, primary and secondary polyamines,
and/or
water. Preferably, mixtures of diols and triols are used to achieve the
desired foaming
properties. The overall polyol hydroxyl number is designed to achieve a 1:1
ratio of first
component to second component (A:B).
The two components are typically delivered through separate lines into a spray
gun
such as an impingement-type spray gun. The first and second components are
pumped
through small orifices at high pressure to form separate streams of the
individual
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components. The streams of the first and second components intersect and mix
with each
other within the gun and begin to react. The heat of the reaction causes the
temperature of
the reactants in the first and second components to increase. This rise in
temperature
causes the blowing agent located in the second component (the "B" side) to
vaporize and
form a foam mixture. As the mixture leaves the gun, the mixture contacts a
surface, sticks
to it, and continues to react until the isocyanate groups have completely
reacted. The
resulting resistance to heat transfer, or R-value, may be from 3.5 to 8 per
inch.
There are several problems associated with conventional polyurethane spray
foams. For example, although sealing a building with such polyurethane spray
foams
reduces drafts and keeps conditioned air inside and external air outside of a
building, there
is a reduction in the ability of moisture to penetrate the building. As a
result, the levels of
moisture and air pollutants rise in these tightly sealed buildings that no
longer permit
moisture penetration into the building.
Another problem associated with conventional polyurethane spray foams is that
the
first component (the "A" side) contains high levels of methylene-diphenyl-di-
isocyanate
(MDI) monomers. When the foam reactants are sprayed, the MDI monomers form
droplets that may be inhaled by workers installing the foam if stringent
safety precautions
are not followed. Even a brief exposure to isocyanate monomers may cause
difficulty in
breathing, skin irritation, blistering and/or irritation to the nose, throat,
and lungs.
Extended exposure of these monomers can lead to a sensitization of the
airways, which
may result in an asthmatic-like reaction and possibly death.
An additional problem with such conventional polyurethane spray foams is that
residual polymeric methylene-diphenyl-di-isocyanate (PMDI) that is not used is
considered to be a hazardous waste. PMDI typically has an NCO of about 20%. In
addition, PMDI can remain in a liquid state in the environment for years.
Therefore,
specific procedures must be followed to ensure that the PMDI waste product is
properly
and safely disposed of in a licensed land fill. Such precautions are both
costly and time
consuming.
In this regard, attempts have been made to reduce or eliminate the presence of
isocyanate and/or isocyanate emission by spray foams into the atmosphere.
Examples of
such attempts are set forth below.
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U.S. Patent Publication No. 2006/0047010 to O'Leary teaches a spray
polyurethane foam that is formed by reacting an isocyanate prepolymer
composition with
an isocyanate reactive composition that is encapsulated in a long-chain, inert
polymer
composition. The isocyanate prepolymer composition contains less than about 1
wt% free
isocyanate monomers, a blowing agent, and a surfactant. The isocyanate
reactive
composition contains a polyol or a mixture of polyols that will react with the
isocyanate
groups and a catalyst. During application, the spray gun heats the polymer
matrix, which
releases the polyols and catalyst from the encapsulating material. The polyols
subsequently react with the isocyanate prepolymer to form a polyurethane foam.
U.S. Patent No. 7,053,131 to Ko, et al. discloses absorbent articles that
include
super critical fluid treated foams. In particular, super critical carbon
dioxide is used to
generate foams that assertedly have improved physical and interfacial
properties.
U.S. Patent No. 6,753,355 to Stollmaier, et al. discloses a composition for
preparing a latex foam that includes a latex and a polynitrilic oxide (for
example, 2,4,6-
triethylbenzene-1,3-dinitrile oxide) or a latex and an epoxy silane. The latex
may be
carboxylated. It is asserted that the composition is stable for at least
twelve months and
that the one-part coating systems can be cured at room temperature without the
release of
by-products.
U.S. Patent No. 6,414,044 to Taylor teaches foamed caulk and sealant
compositions that include a latex emulsion and a liquid gaseous propellant
component.
The foamed compositions do not contain a gaseous coagulating component.
U.S. Patent No. 6,071,580 to Bland, et al. discloses an absorbent, extruded
thermoplastic foam made with blowing agents that include carbon dioxide. The
foam is
allegedly capable of absorbing liquid at about 50 percent or more of its
theoretical volume
capacity.
U.S. Patent No. 5,741,823 to Hsu teaches producing a smooth, hard coating on a
wood substrate. The coating is made of a foamed, polymerized latex emulsion
and is
applied on the surface of a wood substrate.
U.S. Patent No. 5,585,412 to Natoli, et al. discloses a process for preparing
flexible
CFC-free polyurethane foams that uses an encapsulated blowing agent. The
process
provides a polyurethane foam having a desired density that avoids the use of
chlorofluorocarbons or other volatile organic blowing agents. The encapsulated
blowing
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agent assertedly supplements the primary blowing action provided by water in
the
manufacture of water-blown polyurethane foam and facilitates in the production
of foam
having the desired density.
U.S. Patent No. 4,306,548 to Cogliano discloses lightweight foamed porous
casts. To
manufacture the casts, expanded non-porous polystyrene foam beads or other
shapes are
coated with a layer of neoprene, natural rubber, or other latex. The coated
polystyrene is then
encased in a porous envelope, and the envelope is applied to a broken limb.
Additional
coated polystyrene is added over the envelope and a gaseous coagulant is added
to gel the
latex, which causes the polystyrene beads to adhere to each other and produce
a unified, rigid
structure.
Despite these attempts to reduce or eliminate the use of isocyanate in spray
foams
and/or reduce isocyanate emission into the air, there remains a need in the
art for a spray
foam that is non-toxic and environmentally friendly.
SUMMARY OF THE INVENTION
In some cases, it may be desirable to provide two-part foam compositions. In
particular, a two-part foam composition is formed of an A-side and a B-side.
The A-side of
the foamable composition includes a functionalized water-dispersible resin
(for example, a
functionalized latex) and/or a functionalized resin (for example, acrylic
solution and the B-
side contains a crosslinking agent that crosslinks at or above room
temperature and
optionally, a non-reactive resin (for example, a non-functionalized latex). In
addition, the
functionalized water-dispersible resin and functionalized water-soluble resin
may contain
from about 1.0 to about 20 wt% functional groups based on the total weight of
the resin.
Additionally, either or both the A-side or the B-side may contain a blowing
agent
package that includes a chemical compound that, when activated by heat or by
light,
generates a gas. Alternatively, the A-side and the B-side may each contain
blowing agent
package that is formed of two components that, when reacted, forms a gas.
Further, either the A-side or the B-side may contain a plasticizer, a
surfactant, a
thickener, and/or an alcohol co-solvent as well as other optional additives
such as foam
promoters, opacifiers, accelerators, foam stabilizers, dyes (for example,
diazo or
benzimidazolone family of organic dyes), color indicators, gelling agents,
flame
retardants, biocides, fungicides, algaecides, fillers (aluminum tri-hydroxide
(ATH)), and/or
conventional blowing agents.
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In one aspect of the present invention, there is provided a method of forming
a foam
comprising: delivering through a first delivery line to an application device
a first component
including a carboxylated acrylic latex with or without an acrylic solution,
and an acid from an
acid-base blowing agent package; delivering through a second delivery line to
the application
device a second component including a base from an acid-base blowing agent
package, a
plasticizer, and a polyfunctional aziridine cross-linking agent; prior to
application, mixing
said first and second components within said application device to form a
reaction mixture,
thereby permitting said crosslinking agent and said carboxylated acrylic latex
to chemically
react in order to build strength in the foam in order to withstand the force
of gravity when
applied to a vertical surface, while simultaneously reacting said acid and
said base to form a
gas to initiate a foaming reaction; and applying the reaction mixture to a
desired surface to
form a foam.
In another aspect of the present invention, there is provided a method of
forming
a foam on a vertical surface, the method comprising: mixing together in an
application
device to form a reaction mixture (a) a first component including an acid from
an
acid-base blowing agent package and a carboxylated latex with or without an
acrylic
solution; and (b) a second component including a base from an acid-base
blowing
agent package and a polyfunctional aziridine crosslinking agent; thereby
permitting
reactants from the first and second components to simultaneously: (i) begin a
crosslinking reaction to build sufficient strength in the foam to withstand
the force of
gravity when applied to a vertical surface, and (ii) combine the acid and base
to generate
a gas to initiate a foaming reaction; and applying the reaction mixture to a
desired
surface to form a foam that cures sufficiently to withstand the force of
gravity when
applied to a vertical surface.
In another aspect of the present invention, there is provided A method of
forming a
foam comprising: mixing in an application device first and second components
of a two part
foamable composition to form a reaction mixture, the first component including
a polyacrylic
acid and a carboxylated latex, the second component including a base from an
acid-base
blowing agent package and a polyfunctional aziridine crosslinking agent, and
at least one of
the first and second components including a thixotropic agent, the mixing
thereby causing in
the reaction mixture: (a) the polyfunctional aziridine crosslinking agent to
crosslink
functional groups on the polyacrylic acid to form a foam support structure in
the presence of
a thixotropic agent that virtually freezes the foam structure to hold it in
place; (b) the
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polyacrylic acid to react with the base of the acid-base blowing agent package
to generate a
gas for forming the foam; and (c) the polyfunctional aziridine crosslinking
agent to crosslink
the carboxylated latex to begin to cure the foam; and applying the reaction
mixture to a
desired surface to form a foam that cures rapidly at room temperature and is
able to withstand
the force of gravity and remain in place when applied to a vertical surface.
The foams disclosed herein can be used in any application where a flexible
foam is
required. Such as spray, molding, extrusion, and injection molding (for
example, reaction
injection molding (RIM)) applications. The foam may be used to fill cavities,
cracks, and
crevasses to enhance the sealing and insulating properties of buildings, cars,
and appliances
or to form backing for carpets. The foam may be used in insulation or
acoustical
applications and in any application where polyurethane foam may be
advantageous. Such
uses include, but are not limited to, residential and commercial buildings,
automobiles,
appliances, and aircraft.
The foam may be used in automotive applications such as automotive seating,
head
liner panels, and in sound dampening applications under the body of the
vehicle or in the
engine compartment. The foam can also be used to replace masticated rubber.
A foam disclosed herein can also be used in furniture applications such as
cushions,
mattresses, topper pads for mattresses, furniture arms and backs, seat
cushions, and
pillows.
A foam disclosed herein may be used in consumer products and personal
products.
Such examples include display and cushion packaging, toys, novelty items, mops
and
sponges, retail and promotional items, perishable goods packaging and cosmetic
applicators.
A foam disclosed herein may also be used in medical applications such as for
lightweight casts and as protection for medical instruments. The foam may also
be used in
the textile industry as clothing and as padding in clothing.
A foam disclosed herein may be used in the building materials industry as an
acoustical and/or thermal insulation in residential or commercial
applications. Examples
include as a spray-on house wrap and as a spray on stud facing to permit the
adhesion of batts
and vapor barrier to the foam. The foam may be affixed to wood we and act as a
means to
adhere a plastic vapor barrier material. The foam may also be manufactured
into a foam tape
which is particularly useful in sealing windows and/or doors.
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A foam disclosed herein may be used in industrial applications such as in
filtration, as
filtration media, as an anti-static grade, as protective packaging and to
provide a cushioned
coating on substrates.
In any of the aforementioned applications, a foam may be layered with other
materials
to form a composite to provide enhanced acoustical, thermal or cushioning
properties. For
example, the foam can be used with wood, flexible and/or rigid foam,
insulation
(acoustical/thermal), metal, fabrics, plastic, and combinations thereof.
Foams disclosed herein may not release any harmful vapors into the air when
applied
or sprayed. Consequently, the foams reduce the threat of harm to individuals
working with or
1 0 located near the foam and can be used in the renovation market, as well
as in houses that are
occupied by persons or animals.
It may also be desirable to provide one-part foam compositions. Generally,
such
compositions may contain a functionalized water-dispersible resin (for
example, a
functionalized latex) and/or a functionalized water-soluble resin (for
example, acrylic
solution), a crosslinking agent that crosslinks at or above room temperature,
and a blowing
agent package. The blowing agent package is a combination of two or more
chemicals that
when mixed together form a gas, such as, for example, an acid and a base.
Although there
are numerous types of functionalized water-dispersible resins that may be used
in the aqueous
latex solution of the latex foam composition, the preferred functionalized
water-dispersible
resin is a functionalized latex. The functionalized water-dispersible resin
and water-soluble
resin may contain from about 1.0 to about 20 wt% functional groups based on
the total
weight of the resin. Optionally, a plasticizer, a surfactant, a thickener, an
alcohol co-solvent,
foam promoters, opacifiers, accelerators, foam stabilizers, dyes (for example,
diazo or
benzimidazolone family of organic dyes), color indicators, gelling agents,
flame retardants,
biocides, fungicides, algaecides, fillers (aluminum tri-hydroxide (ATH)),
and/or conventional
blowing agents may be included in the foamable one-part composition. In one
exemplary
embodiment of the one-part foam composition, a dry acid and a dry base (that
is, the blowing
agent package) are encapsulated in one or two protective, non-reactive shells
that can be
broken or melted at the time of the application of the foam. In a separate
embodiment, the
crosslinking agent and either the acid or the base are encapsulated in an
encapsulating shell.
Other non-limiting, exemplary one-part foam embodiments of the present
invention include a
foamable composition where the acid or the base is encapsulated or every
component but the
functionalized water-dispersible resin (for example, a functionalized latex)
and/or a
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functionalized water-soluble resin is encapsulated. The protective,
encapsulating shell(s)
may be heat activated, shear activated, photo-activated, sonically destructed,
or activated or
destroyed by other methods known to those of skill in the art. In use, the
inventive foams
may be sprayed into either an open cavity, such as between wall studs, into a
closed cavity
where it expands to seal any open spaces, or it may be used as a sealant to
air infiltration by
filling cracks and/or crevices in a building's roof or walls. Desirably, the
application of the
foam is a continuous spray process. Alternatively, the foam may be added to a
mold and
used to form items such as cushions, mattresses, pillows, and toys.
It may further be desirable to provide a method of forming a foam from a two-
part
foamable composition. To form such a two-part foam, the components of the A-
side and the
components of the B-side as described above are delivered through separate
lines into a spray
gun, such as an impingement-type spray gun. The components of the A-side and
the
components of the B-side are pumped through separate small orifices at high
pressure to form
streams of the components of the A-side and the B-side. The streams of the A-
and B-side
components intersect and mix with each other within the gun and begin to
react. Specifically,
when the A-side and B-side components meet, the blowing agent package reacts
or degrades
to form a gas and the crosslinking agent simultaneously reacts with the
functional groups on
the functionalized resin to support the foamed structure. The foaming reaction
occurs until
all of the blowing agent(s) have been reacted and no more gas is generated.
The crosslinking
of the functional groups on the functionalized resin quickly builds strength
in the foam and
permits the foam to withstand the force of gravity when it is placed, such as,
for example, in a
vertical wall cavity during application. The final foamed product becomes
cured to the touch
within minutes after application. In exemplary foamed products, the foam
hardens within 2
minutes. The resulting resistance to heat transfer, or R-value, may be from
about 3.5 to about
8 per inch.
It may also be desirable to form a molded product using a two-part foam
composition.
In particular, the A-side components and the B-side components of the two-part
foam
composition discussed in detail above are combined to form a reaction mixture.
The reaction
mixture formed of the A-side components and B-side components are added to a
mold, where
the reaction mixture reacts without any physical or other interference.
Specifically, the
blowing agent(s) reacts or degrades to form a gas while the crosslinking agent
and the
functionalized latex react to support the foamed structure. The crosslinking
reaction and the
gas generation occur simultaneously or nearly simultaneously. The foaming
reaction occurs
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until all of the blowing agent(s) have reacted or degraded and no more gas is
generated.
When the foam is hardened (that is., cured), it is released from the mold in
the shape of a
desired product. The curing takes place in a matter of minutes, typically less
than about two
minutes.
It may further de desirable to provide a method of making a foam from a one-
part
foam composition. As discussed above, the one-part foam compositions generally
contain a
functionalized water-dispersible resin (for example, a functionalized latex)
and/or a
functionalized water-soluble resin (for example, acrylic solution), a
crosslinking agent that
crosslinks at or above room temperature, and a blowing agent package. The
blowing agent
package is a combination of two or more chemicals that when mixed together
form a gas,
such as, for example, an acid and a base. To form a foam from a one-part foam
composition,
non-encapsulated materials (such as the functionalized water-dispersible
and/or water-
dispersible resin) are mixed with encapsulated materials (such as the
crosslinking agent and
blowing agent package) to form a dispersion or reaction mixture. The reaction
mixture is
substantially non-reactive due to the encapsulation and/or separation of
reactive components
within the foamable composition. Consequently, the foamable one-part foam
composition is
stable for extended periods of time. A single stream of the reaction mixture
may be fed into
an application gun that has the ability to mix the dispersion within the gun.
Once the
dispersion is inside the gun, the encapsulated component(s) are released, and
the acid and the
base (that is, the blowing agent package) react to generate a gas (CO2) and
the crosslinking
agent reacts with the functional groups on the resin to support the foamed
structure. The
simultaneously reacting mixture may be sprayed from the gun to a desired
location where the
mixture continues to react and form either open or closed cell foams. The
foaming reaction
occurs until all of the acid and base have been reacted and no more gas is
generated. The
final foamed product becomes cured to the touch within minutes after
application. In
exemplary foamed products, the foam hardens in less than about 2 minutes. The
foam may
have an R-value from about 3.5 to about 8 per inch.
It may be an advantage that the foams do not contain the harmful chemicals
found in
conventional polyurethane spray foams, such as, for example, MDI monomers. As
a result,
the foams do not contain harmful vapors that may cause skin or lung
sensitization or generate
toxic waste. Additionally, the foams do not emit harmful vapors into the air
when the foam is
sprayed, such as when filling cavities to seal and/or insulate a building. The
foams are safe
for workers to install and, therefore, can be used both in the house
renovation market and in
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occupied houses. Additionally, because there are no harmful chemicals in the
foams, the
foams can be safely disposed without having to follow any stringent hazardous
waste
disposal precautions.
It may be another advantage that the foams may be applied using existing spray
equipment designed for conventional two-part spray polyurethane foam systems
without
clogging the spray equipment. Thus, the application gun is capable of repeated
use without
clogging and the resulting necessary cleaning when the foams of the present
invention are
utilized.
It may be yet another advantage that the use of an alcohol co-solvent to
partially
replace the water in the serum allows for a faster drying/curing of the foam
and improves cell
structure.
It may be a further advantage that the components of the foam compositions may
be
carefully chosen to result in a tacky or sticky foam that can be used to hold
the fiberglass batt
in place when used to fill cracks or crevasses.
It may also be an advantage that the components of the one-part foam
compositions in
which the crosslinking agent and base or the acid and base are encapsulated
may be mixed
and stored in one container without significant reaction until the composition
is used.
It is a feature of the present invention that the foam compositions may be
used to fill
open or closed cavities or to fill cracks and crevasses.
It is also feature of the present invention that the foam compositions may be
one or
two part compositions.
It is another feature of the present invention that the dry acid and dry base
forming the
blowing agent can be encapsulated in a single encapsulant.
It is a further feature of the present invention that the dry acid and dry
base forming
the blowing agent can be encapsulated in separate encapsulating materials.
It is yet another feature of the present invention that blowing agent or
components
forming the blowing agent may be encapsulated a wax, a gelatin, a low melting,
semi-
crystalline, super-cooled polymer such as polyethylene oxide or polyethylene
glycol, or a
polymer or acrylic that can be broken at the time of the application of the
foam.
The foregoing and other features, and advantages of the invention will appear
more
fully hereinafter from a consideration of the detailed description that
follows.
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DETAILED DESCRIPTION AND PREFERRED EMBODIMENTS OF THE INVENTION
Unless defined otherwise, all technical and scientific terms used herein have
the same
meaning as commonly understood by one of ordinary skill in the art to which
the invention
belongs. Although any methods and materials similar or equivalent to those
described herein
can be used in the practice or testing of the present invention, the preferred
methods and
materials are described herein. The terms "foamable composition", and "foam
composition"
may be interchangeably used in this application. In addition, the terms
"encapsulant" and
"encapsulating material" may be used interchangeably herein.
The present invention relates to foams used to fill cavities of buildings to
improve the
sealing and insulation properties. Additionally, the inventive foams may be
used to seal
cracks and crevasses, such as those around windows and doors. The foams may
also be used
to form items such as cushions, carpet backing, mattresses, pillows, and toys.
The inventive
foams can be used in spray, molding, extrusion, and injection molding (for
example, reaction
injection molding (RIM)) applications. In one exemplary embodiment, the
inventive foam is
formed from two components, namely, an A-side and a B-side. In particular, the
A-side of
the foam composition includes a functionalized water-dispersible
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and/or a functionalized water-soluble resin (for example, a functionalized
latex or a
functionalized latex and an acrylic solution) and the B-side contains a
crosslinking agent,
and optionally, a non-reactive resin (for example, a non-functionalized
latex). Either or
both the A-side or the B-side may contain a blowing agent package.
Alternatively, the A-
side and the B-side may each contain a component forming a blowing agent
package. A
plasticizer, a surfactant, a thickener, and/or a co-solvent may optionally be
included in
either the A- and/or B-side.
In an alternate embodiment, the crosslinking agent and an acid or a base are
encapsulated in an encapsulating material to form a one-part foam composition.
In a
further alternate embodiment, the foamable composition includes a
functionalized water-
dispersible and/or a functionalized water-soluble resin, a crosslinking agent,
and an
encapsulated dry acid and/or dry base. In another exemplary embodiment, every
component but the functionalized water-dispersible and/or a functionalized
water-soluble
resin is encapsulated. Unlike conventional spray polyurethane foams, the foams
of the
present invention do not contain isocyanate. Therefore, no MDI monomers are
present in
the inventive foams. Because the inventive foam does not contain isocyanate,
no harmful
chemicals are emitted during installation of the foams.
It is preferred that the foams of the present invention, as well as the
components
thereof, meet certain performance properties, or Fitness for Use ("FFU")
criteria. In
particular, the chemical property FFUs that the inventive foam should meet
include the
following criteria:
= The foam should adhere to various materials such as wood, metal, concrete
and
plastic
= The chemical constituents should be as safe as possible. If a hazardous
chemical is
used, it should not be introduced or atomized into the air where it can be
inhaled
= The foam may be chemically foamed through the use of a blowing agent or
it may
be mechanically foamed with a gas
= The installer of the latex foam should be able to work with the material
without
any specialized personal protective equipment ("PPE"), such as a breathing
apparatus, although safety glasses, dust mask, and gloves are acceptable
= The foam should not lend itself to molding or fungus growth (ASTM C1338)
= The foam should not contain a food source for insects or rodents
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= There should be a minimum shelf life of the un-reacted constituents of 12
months.
It is also desirable that the inventive foams of the present invention meet
certain
physical property FFUs. The physical property FFUs that the inventive foam
should meet
include the following:
= The foam weight should be between about 0.5 and about 5.0 pounds per
cubic foot
= The foam should be fluid enough to be sprayed either at room temperature
or by
heating (viscosity of <10,000 cP at a high shear rate)
= The foam should not sag or fall in the cavity
= The foam should fill the entire cavity or be used to coat the cavity with
an air
barrier
= Ideally, the foam should be a closed-cell variety, but an open-cell
variety is
acceptable if the open-cell variety is necessary to achieve the other FFUs
= The foam should have a thermal resistance (R-value) of at least 3.7
Fft2h/BTU per
inch
= The foam should be non-sagging and non-dripping (that is, fire retardant)
during a
fire
= The foam should not corrode metal objects such as screws, nails,
electrical boxes,
and the like
= Air infiltration should be negligible (ASTM E283-04) (spec 0.4 cfm/ sq
ft)
= Water vapor infiltration should be greater then 1 perm or 5.72x10-8 g/Pa-s-
m2
= The foam should have low or no odor.
As discussed above, the A-side of the composition for the foams according to
one
exemplary embodiment of the present invention includes a functionalized water-
dispersible and/or a functionalized water-soluble resin. Preferably, the
functionalized
water-dispersible resin is a functionalized latex, and even more preferably,
the latex
system is an acrylic emulsion. Non-limiting examples of suitable water-soluble
resins for
use in the inventive compositions include acrylic solutions and polyols. In
addition to the
functionalized water-dispersible and/or functionalized water-soluble resin,
the serum can
contain a polyacrylic oligomer to increase the total number of the functional
groups. It is
to be appreciated that although any functionalized water-soluble and/or
functionalized
water-dispersible resin(s) may be used as a component in the foamable
compositions
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described herein, reference will be made to a preferred embodiment,
functionalized latexes
with or without an acrylic solution.
There are numerous types of latexes that may be used as the functionalized
water-
dispersible component in the aqueous resin solution of the present invention.
Non-limiting
examples of suitable latexes include natural and synthetic rubber resins, and
mixtures
thereof, including thermosettable rubbers; thermoplastic rubbers and
elastomers including,
for example, nitrile rubbers (for example, acrylonitrile-butadiene);
polyisoprene rubbers;
polychloroprene rubbers; polybutadiene rubbers; butyl rubbers; ethylene-
propylene-diene
monomer rubbers (EPDM); polypropylene-EPDM elastomers; ethylene-propylene
rubbers; styrene-butadiene copolymers; styrene-isoprene copolymers; styrene-
butadiene-
styrene rubbers; styrene-isoprene-styrene rubbers; styrene-ethylene-butylene-
styrene
rubbers; styrene-ethylene-propylene-styrene rubbers; polyisobutylene rubbers;
ethylene
vinyl acetate rubbers; silicone rubbers including, for example, polysiloxanes;
methacrylate
rubbers; polyacrylate rubbers including, for example, copolymers of isooctyl
acrylate and
acrylic acid; polyesters; polyether esters; polyvinyl chloride; polyvinylidene
chloride;
polyvinyl ethers; polyurethanes and blends; and combinations thereof,
including, for
example, linear, radial, star, and tapered block copolymers thereof. The
preferred latex for
use in the inventive foam composition is a carboxylated acrylic latex.
As discussed above, water-dispersible and water-soluble resin is
functionalized. The
functional group may be any functional group capable of crosslinking,
including
carboxylic acid, hydroxyl, methylol amide groups, and sulfonates. It is
preferred that the
water-dispersible and/or water-soluble resin(s) contain from about 1.0 to
about 20 wt%
functional groups based on the total dry weight of the resin, and even more
preferably
from about 2.0 to about 15.0 wt% functional groups based on the total dry
weight of the
resin. The functionality of the functionalized water-dispersible and/or water-
soluble resin
can be adjusted by adding or removing functional groups to or from the resin
backbone to
reach the optimum amount of crosslinking and ultimately the optimum strength
and
modulus of the foam. In preferred embodiments, a polyacrylic solution is added
in
amount sufficient to add up to about 50% carboxylate functionality to the
final dry foam
composition.
The B-side of the foam composition, as indicated previously, contains a
crosslinking
agent and optionally, a non-reactive resin such as, for example, a non-
functionalized latex.
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In particular, the non-reactive resin is a resin that does not react with the
crosslinking
agent, but is otherwise non-limiting. The crosslinking agent is a compound
that crosslinks
at or above room temperature, such as polyfunctional aziridines (for example,
XAMA,
available from Bayer Corporation). Other suitable crosslinking agents include,
but are not
necessarily limited to, multifunctional carbodiimide'S (for example, Hardner
CD, available
from Rotta Corporation), melamine formaldehyde, polysiloxanes, and
multifunctional
epoxies (for example, cycloaliphatic diepoxides). It is to be appreciated that
when a
polyfunctional aziridine (for example, XAMA) is used as the crosslinking
agent, other
compounds such as plasticizers or epoxy diluents may be utilized to carry the
polyfunctional aziridine and lower the viscosity of the B-side. The
crosslinking agent may
be present in the B-side in an amount from about 1.0 to about 30 percent by
weight of the
dry foam composition, preferably in an amount from about 3.0 to about 20
percent by
weight. Although a mole ratio of the resin functional groups to the
crosslinking agent
functional groups of 1:1 is preferred, this molar ratio is variable and may
encompass a
wider range, such as, for example, from 0.5:1 to 2:1 to provide the optimum
crosslinking
in the final foam products.
Additionally, the A-side and/or B-side contains a blowing agent package. The
blowing agent package may be the combination of two or more chemicals or
compounds
that when mixed together form a gas (for example, an acid and a base such as
are
discussed below) or a chemical compound that, when heat or light activated,
forms a gas.
The generated gas may be CO2, N2, 02, H2, or other non-carcinogenic, gases.
For
instance, azodicarbonamide is a chemical compound that, upon heating, releases
N2 gas,
and would be a suitable blowing agent in the foamable composition.
Additionally;
alkylsiloxanes, which may release H2 when reacting with amine hardeners, may
be used as
a blowing agent in the instant invention. Other examples include diazo
compounds (that
is, CH2N2) and aliphatic azide (that is, R-N=N=N), which decompose on
irradiation to
give nitrogen gas, and 1-naphtyl acetic acid and n-butyric acid, which
generate carbon
dioxide (CO2) upon photodecarboxylation. Phase change blowing agents such as
low
boiling point hydrocarbons (for example, cyclopentane and n-pentane) and inert
gases
= 30 such as air, nitrogen, carbon dioxide can also be used. It is to
be appreciated that the
chemical compound is not a conventional blowing agent in the sense that it is
a hydro- -
fluorocarbon (HFC) or a hydro-chloro-fluorocarbon (HCFC) blowing agent.
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If the blowing agent =package is a single chemical compound, the compound may
be
included in either the A- or the B-side. On the other hand, if the blowing
agent package is
formed of two compounds that react to form a gas when mixed, the two
components are
separated and placed with one component in the A-side and the other component
in the B-
side.
For instance, an acid and a base forming the blowing agent package may be
separated
and the acid placed in the A-side and the base placed in the B-side (or vice
versa). Thus,
in addition to the functionalized latex solution, the A-side may contain at
least one acid.
The acid may have a solubility of 0.5 g/100 g of water or greater at 30 C.
Preferably, the
acid is a dry acid powder with or without chemically bound water. Non-
exclusive
examples of suitable acids include citric acid, oxalic acid, tartaric acid,
succinic acid,
fumaric acid, adipic acid, maleic acid, malonic acid, glutaric acid, phthalic
acid,
metaphosphoric acid, or salts that are convertible into an acid that is an
alkali metal salt of
citric acid, tartaric acid, succinic acid, fumaric acid, adipic acid, maleic
acid, oxalic acid,
malonic acid, glutaric acid, phthalic acid, metaphosphoric acid, or a mixture
thereof.
Examples of salts which are convertible into acids include, but are not
limited to,
aluminum sulfate, calcium phosphate, alum, a double salt of an alum, potassium
aluminum
sulfate, sodium dihydrogen phosphate, potassium citrate, sodium maleate,
potassium
tartrate, sodium fumarate, sulfonates, and phosphates. The acid(s) may be
present in an
amount from about 1.0 to about 30 percent by weight of the dry foam
composition,
preferably in an amount from about 3.0 to about 20 percent by weight.
When the acid and base of the blowing agent package are separated and the A-
side
contains the acid, the B-side contains at least one base that acts as an acid
sensitive
chemical blowing agent. Generally, the weak base contains anionic carbonate or
hydrogen
carbonate, and, as a cation an alkali metal, an alkaline earth metal or a
transition metal.
Examples of bases suitable for use in the practice of this invention include
calcium
carbonate, barium carbonate, strontium carbonate, magnesium carbonate, lithium
carbonate, sodium carbonate, potassium carbonate, rubidium carbonate, cesium
carbonate,
calcium hydrogen carbonate, barium hydrogen carbonate, strontium hydrogen
carbonate,
magnesium hydrogen carbonate, lithium hydrogen carbonate, sodium hydrogen
carbonate,
potassium hydrogen carbonate, rubidium hydrogen carbonate, cesium hydrogen
carbonate,
= and bicarbonates and combinations thereof. In preferred embodiments, the
base is sodium
CA 02709801 2014-03-05
bicarbonate. The base may be present in an amount from about 1.0 to about 30%
by weight
of the dry foam composition. In preferred embodiments, the base is present in
the B-side in
an amount from about 3.0 to about 20% by weight of the dry foamable
composition. Sodium
bicarbonate and citric acid in a ratio of 7:1 to 4:1 are the preferred base
and acid acting as the
blowing agent package.
In addition to the components set forth above, the A-side and/or the B-side
may
contain one or more surfactants to impart stability to the acrylic during the
foaming process,
to provide a high surface activity for the nucleation and stabilization of the
foam cells, and to
modify the surface tension of the latex suspension to obtain a finely
distributed, uniform
foam with smaller cells. Useful surfactants include cationic, anionic,
amphoteric and
nonionic surfactants such as, for example, carboxylate soaps such as oleates,
ricinoleates,
castor oil soaps and rosinates, quaternary ammonium soaps and betaines, amines
and
proteins, as well as alkyl sulphates, polyether sulphonate (TritonTm X200K
available from
Cognis), octylphenol ethoxylate (Triton X705 available from Cognis),
octylphenol
polyethoxylates (for example, Triton X110 available from Cognis), alpha olefin
sulfonate,
sodium lauryl sulfates (for example, Stanfax 234 and Stanfax 234LCP from Para-
Chemicals),
ammonium laureth sulfates (for example, Stanfax 1012 and Stanfax 969(3) from
Para-
Chemicals), ammonium lauryl ether sulfates (for example, Stanfax 1045(2) from
Para-
Chemicals), sodium laureth sulfates (for example, Stanfax 1022(2) and Stanfax
(1023(3)
from Para-Chemicals), and sodium sulfosuccinimate (for example, Stanfax 318
from Para-
Chemicals). The surfactant may be present in the A- and/or B-side in an amount
from about
0 to about 20% by weight of the dry foam composition.
Further, either or both the A-side and B-side may contain a thickening agent
to adjust
the viscosity of the foam. It is desirable that the A-side and the B-side have
the same or
nearly the same viscosity to achieve a 1:1 ratio of the A-side components to
the B-side
components. A 1:1 ratio permits for easy application and mixing of the
components of the A-
side and B-side. Suitable examples of thickening agents for use in the
foamable composition
include calcium carbonate, methyl cellulose, ethyl cellulose, hydroxyethyl
cellulose (for
example, Cellosize HEC available from Union Carbide"), alkaline swellable
polyacrylates
(for example, Paragum 500 available from Para-Chemml), sodium polyacrylates
(for
example, Paragum 104 available from Para-Chem), bentonite clays, and Laponiten
RD clay
(a synthetic layered silicate), glass fibers, cellulose fibers, and
polyethylene oxide. The
Laponite products belong to a family of synthetic, layered silicates produced
by the
16
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Southern Clay Products Corporation. The Laponite products are thixotropic
agents that
"virtually freeze" the foam structure while the structure is curing to prevent
the structure from
collapsing. As used herein, the phrase "virtually freeze" is meant to denote a
previously
fluid/viscous material that is now substantially immobilized by an internal
scaffolding-like
structure, which may be provided by a thixotropic agent. The thickening agent
may be
present in an amount up to about 50% by weight of the dry foam composition.
Preferably,
the amount of thickening agent present is about 0 to about 20% by weight,
based on the dry
foamable composition, depending upon the nature of the thickening agent.
A plasticizer may also, or alternatively, be present in the A-side and/or B-
side to
adjust the viscosity of the foam. Non-limiting examples of suitable
plasticizers include
phthalate ester, dimethyl adipate, dimethyl phthalate, epoxidized crop oils
(for example,
DrapexTM 10.4, Drapex 4.4, and Drapex 6.8 available from ChemturaTm). The
plasticizer
may be present in the foamable composition in an amount from about 0 to about
20% by
weight of the dry foam composition. Desirably, the plasticizer is present in
an amount from
about 0 to about 15% by weight.
Further, an alcohol such as ethanol or isopropanol may be present in the foam
composition in the A-side and/or the B-side. The alcohol is preferably
miscible with water
and has a low boiling point. The alcohol acts as a co-solvent and replaces a
portion of the
water in the latex serum. Utilizing an alcohol co-solvent allows for a quicker
drying/curing
time after the foam's application. Additionally, the co-solvent assists in
creating a foam with
a fine cell structure. Although not wishing to be bound by theory, it is
believed that the
higher vapor pressure of the alcohol causes the alcohol to be driven off more
quickly than the
water in the latex solution, and that the alcohol carries the water molecules
as the alcohol is
removed. The co-solvent is used in small quantities, typically from about 1.0
to about 5.0%
by weight of the foam composition.
Depending on the type of particles used in the latex solution, the A- or B-
side may
also include other optional, additional components such as, for example, foam
promoters,
pacifiers, accelerators, foam stabilizers, dyes (for example, diazo or
benzimidazolone family
of organic dyes), color indicators, gelling agents, flame retardants,
biocides,
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fungicides, algaecides, fillers (aluminum tri-hydroxide (ATH)), and/or
conventional
blowing agents. It is to be appreciated that a material will often serve more
than one of the
aforementioned functions, as may be evident to one skilled in the art, even
though the
material may be primarily discussed only under one functional heading herein.
The
additives are desirably chosen and used in a way such that the additives do
not interfere
with the mixing of the ingredients, the cure of the reactive mixture, the
foaming of the
composition, or the final properties of the foam.
To form a two-part spray foam of the present invention, the components of the
A-side
and the components of the B-side are delivered through separate lines into a
spray gun,
such as an impingement-type spray gun. The two components are pumped through
small
orifices at high pressure to form streams of the individual components of the
A-side and
the B-side. The streams of the first and second components intersect and mix
with each
other within the gun and begin to react. For example, if the blowing agent
package is an
acid and a base (with the acid contained in the A-side and the base contained
in the B-
side), the acid and base react to form carbon dioxide (CO2) gas. If the
blowing agent is a
single chemical compound, it degrades to form a gas, such as CO2 or N2, upon
the
application of heat or light. In any event, the foaming reaction occurs until
all of the
blowing agent(s) have been reacted and no more gas is generated.
In addition, the crosslinking agent concurrently (simultaneously) reacts with
the
functional groups on the acrylic to support the foamed structure. The
crosslinking is
important for capturing the bubbles generated by the evolution of the gas in
their original,
fine structure before they can coalesce and escape the foam. It is to be
appreciated that a
fine foam structure is more desirable and more beneficial than a coarse foam
structure in
order to achieve high thermal performance. Additionally, the crosslinking of
the
functional groups on the functionalized latex quickly builds strength in the
foam and
permits the foam to withstand the force of gravity when it is placed, for
example, in a
vertical wall cavity during application. The final foamed product becomes
cured to the
touch within minutes after application. In exemplary foamed products, the foam
hardens
within about 2 minutes. The resulting resistance to heat transfer, or R-value,
may be from
about 3.5 to about 8 per inch.
In an alternate embodiment, the blowing agent package includes an acid and a
base
and the components of the B-side are encapsulated and added to the A-side,
thereby
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creating a one-part foam composition. Specifically, the crosslinking agent and
the base
(that is, acid sensitive chemical blowing agent) are encapsulated in one or
two protective,
non-reactive shells that can be broken or melted at the time of the
application of the foam.
For example, the crosslinking agent and the base may be encapsulated in a wax
or gelatin
that can be melted at the time of the application of the foam. Desirably, the
wax has a
melting point from about 120 F to about 180 F, and more preferably has a
melting point
from about 120 F to about 140 F. Alternatively, the encapsulating shell may
be formed
of a brittle polymer (such as a melamine formaldehyde polymer) or an acrylic
that can be
broken or sheared at the time of the application of the foam to initiate the
foaming
reaction. The protective shell(s) surrounding the crosslinking agent and base
may be heat
activated, shear activated, photo-activated, sonically destructed, or
activated or destroyed
by other methods known to those of skill in the art.
Optionally, the encapsulating material may be a low melting, semi-crystalline,
super-
cooled polymer. Non-limiting examples of low melting polymers include
polyethylene
oxide (PEO) and polyethylene glycol (PEG). A preferred low-melting polymer for
use as
an encapsulant is a polyethylene oxide that has an average molecular weight
from about
100,000 Dalton to about 8,000,000 Dalton. Additionally, the glass transition
temperature
(Tg) of the super-cooled polymer may be adjusted to the application
temperature of the
reaction system by blending polymers. For example, polymer blends such as a
blend of
polyvinylchloride (PVC) and polyethylene oxide (PEO) may be used to "fine
tune" the
glass transition temperature and achieve a desired temperature at which the
polymer melts
or re-crystallizes to release the crosslinking agent and base. With a PVC/PEO
blend, the
desired glass transition temperature is a temperature between the Tg of
polyvinyl chloride
and the Tg of the polyethylene oxide and is determined by the ratio of PVC to
PEO in the
polymer blend. When the super-cooled polymer is heated above its glass
transition
temperature, such as in a spray gun, the polymer re-crystallizes and the
crosslinking agent
and base is expelled from the polymer. This expulsion of the crosslinking
agent and base
is due to the change in free volume that occurs after re-crystallization of
the polymer.
The combination of the A-side components and the encapsulated crosslinking
agent
and blowing agent(s) may be mixed to form a dispersion (reaction mixture). The
dispersion is substantially non-reactive because the crosslinking agent
remains
encapsulated within the encapsulating shell. The phrase "substantially non-
reactive" as
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used herein is meant to indicate that there is no reaction or only a minimal
reaction
between the A-side components and the encapsulant in the dispersion. As a
result, the
one-part foamable reactive composition is stable for extended periods of time.
A single stream of the dispersion containing the functionalized latex,
encapsulated
crosslinking agent and blowing agent, and optional surfactants, plasticizers,
thickening
=
agents, and/or co-solvents may then be fed into an application gun, such as a
spray gun,
that has the ability to mix and/or heat the dispersion within the gun. The one-
part foam of
the present invention requires no expensive or complicated spraying equipment,
and is a
simple gun, a simple diaphragm, or drum pump. These types of guns are less
likely to
clog and are also easy to maintain and clean.
Once the dispersion is inside the gun, the crosslinking agent and base are
released from
the encapsulating material. For example, the dispersion may be heated within
the gun to a
temperature above the melting point of the long chain polymer or wax
containing the
crosslinking agent and base so that the crosslinking agent and base are
released from the
polymer or wax. In this example, the dispersion is heated to a temperature of
about 130 F
to about 180 F. In addition, the mixing action within the gun may assist in
the release of
the crosslinking agent and base from the encapsulant. Alternatively, the
encapsulating
shell of the crosslinking agent and base may be shear activated, sonically
activated, photo
activated, or destroyed by any other suitable method known to those of skill
in the art.
Once the crosslinking agent and blowing agent package are released from the
polymer
shell, crosslinking between the crosslinking agent and the functional groups
on the
functionalized latex begins and the blowing agent concurrently degrades or
reacts to form
a gas to initiate the foaming reaction and form the foam. The simultaneously
reacting
mixture is sprayed from the gun to a desired location where the mixture
continues to react
and form either open or closed cell foams. The foam may have an R-value from
about 3.5
to about 8 per inch. The foam is advantageously used in residential housing,
commercial
buildings, appliances (for example, refrigerators and ovens), and hot tubs.
In a further alternative embodiment in which a one-part foam composition is
utilized,
the foam is formed by encapsulating the dry acid powder and the dry, powdered
base in a
single encapsulating shell, such as the encapsulating shell described in
detail above. It is
to be appreciated that separately encapsulating the acid and the base is
considered to be
within the purview of this invention. The encapsulated acid and base are mixed
with a
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functionalized latex solution, at least one crosslinking agent, and optionally
one or more of
a surfactant, thickener, plasticizer, and/or co-solvent to form a reaction
mixture or
dispersion. It is to be noted that there is no foaming reaction due to the
encapsulation of
the acid and base. Consequently, the reactive mixture is stable for extended
periods of
time. The mixture is of a sufficient viscosity to enable its passage through a
spray-type
application gun. As with the embodiment discussed previously, the
encapsulating shell is
destroyed, such as by heat, sonic destruction, shear forces, or other known
methods, to
release the acid and/or the base. Once the acid and base are released from the
encapsulating material, crosslinking between the crosslinking agent and the
carboxy
groups on the functionalized latex begins and the acid and base react to form
a gas, which
initiates the foaming reaction and forms the inventive foam.
Other non-limiting, exemplary one-part foam embodiments of the present
invention
include a foamable composition where the crosslinking agent and acid is
encapsulated, the
acid or the base is encapsulated, or every component but the functionalized
latex is
encapsulated. In each of these embodiments, the foaming and crosslinking
reactions begin
when the encapsulated material is released from the encapsulating, protective
shell, such
as by heat, sonic destruction, shear forces, or photo activation.
Additionally, the one part-
foam compositions may optionally include thickening agents, plasticizers,
alcohol co-
solvents, foam promoters, opacifiers, accelerators, foam stabilizers, dyes
(for example,
diazo or benzimidazolone family of organic dyes), color indicators, gelling
agents, flame
retardants, biocides, fungicides, algaecides, fillers (aluminum tri-hydroxide
(ATH)),
and/or conventional blowing agents.
Yet another exemplary embodiment of the invention includes utilizing a phase
change
blowing agent as the blowing agent package. To form a foam utilizing a phase
change
blowing agent such as a low boiling point hydrocarbon or inert gas, a
functionalized
water-soluble or functionalized water-dispersible resin (for example,
functionalized latex
or functionalized latex and acrylic solution), crosslinking agent, and phase
change blowing
agent are pressurized, such as in a pressurized spray-type container. Upon
release of the
functionalized water-soluble or functionalized water-dispersible resin, the
crosslinking
agent, and the blowing agent from the pressurized container (for example,
release into
atmospheric pressure), the blowing agent changes from a liquid to a gas to
initiate the
foaming reaction while the crosslinking agent and functionalized resin react
to form an
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internal foam structure. The foaming reaction continues until all of the
blowing agent has
been converted into a gas.
In use, the inventive foams may be sprayed into either an open cavity, such as
between
wall studs, or into a closed cavity where it expands to seal any open spaces.
The
application is desirably a continuous spray process. Alternatively, the foams
may be
applied in a mariner to fill or substantially fill a mold or fed into an
extruder or an injection
molding apparatus, such as for reaction injection molding (RIM), and used to
form items
such as cushions, mattresses, pillows, and toys. For example, a functionalized
water-
soluble or functionalized water-dispersible resin (for example, functionalized
latex or
functionalized latex and acrylic solution), a crosslinking agent, and a
blowing agent may
be mixed and applied to a mold where the crosslinking agent reacts with the
functionalized
resin while the blowing agent degrades or reacts to form a gas and initiate
the foaming
reaction.
The foams of the present invention may be used to insulate buildings such as
homes
from temperature fluctuations outside of the building's envelope. The foams
may serve
both as a conductive and a convective thermal barrier. The foams of the
present invention
may also serve as a sealant to air infiltration by filling cracks and/or
crevices in a
building's roof or walls. Additionally, the foams may be used to seal cracks
or crevasses
around doors, windows, electric boxes, and the like.
The foams of the present invention are preferably non-structural foams. The
soft foam
nature of the functionalized water-soluble and functionalized water-
dispersible resins
allows for easy compaction. As such, the inventive foams have several
benefits. For
example, there is no post-application waste to an open wall cavity. If there
is an
overfilling of the cavity, the drywall simply compresses the foam back into
the cavity.
The inventive foams are giving, so it will not apply a significant pressure to
the drywall
and little or no bowing or detachment of the drywall will occur.
Another advantage of the foams of the present invention is the safe
installation of the
foam into cavities. The foams do not release any harmful vapors into the air
when applied
or sprayed. Therefore, the inventive foams reduce the threat of harm to
individuals
working with or located near the foam. In addition, the application of the
foams is more
amenable to the installer as he/she will not need to wear a special breathing
apparatus
during installation.
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Another advantage of the inventive foams is that it can be used in the
renovation
market, as well as in houses that are occupied by persons or animals.
Existing,
conventional spray polyurethane foams cannot be used in these applications
because of the
generation of high amounts of free isocyanate monomers that could adversely
affect the
occupants of the dwelling. As discussed above, exposure of isocyanate monomers
may
cause irritation to the nose, throat, and lungs, difficulty in breathing, skin
irritation and/or
blistering, and a sensitization of the airways.
Yet another advantage of the present invention is that the components of the
one-part
foam compositions in which the crosslinking agent and base and/or the acid are
encapsulated may be mixed and stored in one container without significant
reaction until
such time that the foam is used. This simplifies the application of the foam
because no
other components need to be added at the point of application. Instead, the
encapsulated
components are activated at the point of application.
It is also an advantage of the present invention is that the components of the
one-part
or two-part foam compositions are carefully chosen to result in a tacky or
sticky foam that
can be used to hold the fiberglass batt in place when used to fill cracks or
crevasses.
The one-part foam compositions are advantageous in they do not require
metering
within the gun. As a result, a simple spray gun having only one inlet may be
utilized to
spray the foam compositions. Without a sophisticated pumping system and
complex spray
gun, producing the inventive one-part foams have low manufacturing costs. In
addition,
the one-part foamable compositions of the present invention are simpler to use
in the field
than conventional two-part foams. Therefore, less training is required to
correctly use the
inventive one-part foam compositions.
Having generally described this invention, a further understanding can be
obtained by
reference to certain specific examples illustrated below which are provided
for purposes of
illustration only and are not intended to be all inclusive or limiting unless
otherwise
specified.
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EXAMPLES
Table 1 sets forth a list of proposed components that may be used to make at
least one
exemplary embodiment of the inventive foam.
Table 1- Proposed Components
Trade Name Description Manufacturer
Functionalized
Latex
Omnapel Carboxylated Acrylic Latex Omnova Solutions, Inc.
NovaCryl Carboxylated Acrylic Latex Omnova Solutions, Inc.
GenFlo Carboxylated SBR Latex Omnova Solutions, Inc.
Non-Functionalized
Latex
AcryGen DV300 Acrylic Latex Omnova Solutions, Inc.
Vycar 660x144 Acrylic Latex Noveon m
F-6694 SBR Latex Omnova Solutions, Inc.
Crosslinking
Agents
XAMA 7 Multifunctional Aziridine Bayer Chemical
Methylhexahydrophthalic
Lindride 56 Lindau Chemical
Anhydride
Hardner CD Carbodiimide Rotta Corp.
YDH 184 Cycloaliphatic Diepoxide Thai Epoxy
Blowing Agents
Sodium Bicarbonate/Citric Acid Aldrich I m
Sodium Carbonate/Citric Acid Aldrich
Calcium Carbonate/Sodium
Aldrich
Bicarbonate/Citric Acid
Surfactant
G-5M Triton Non-ionic Surfactant Dowim Chemical
ABEXIm Non-ionic Surfactant Omnova Solutions, Inc.
Stanfax 234 Sodium Lauryl Sulfate ParaChem
Thickening Agents
Cellosize0 HEC Hydroxyethyl Cellulose Dow Chemical
Laponite0 Clay Southern Clay
Cabosil Fumed Silica Cabot I m
Plasticizer
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Dioctyl Adipate Aldrich
Diisoocytyl Adipate Aldrich
Dimethyl Phthalate Aldrich
Dioctyl Phthalate Aldrich
Encapsulants
Melamine Formaldehyde Aldrich
Acrylic Solution
AcryGen 8546 26% Acrylic Solution
Omnova Solutions, Inc.
Prophetic examples of forming the foam, encapsulated catalyst, and the
reactive
mixture using the exemplary components identified in Table 1 are set forth in
Tables 2, 3,
and 4.
10
20
25.
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Table 2 ¨ Two-Part Foam Compositions
Component Foam 1 Foam 2 Foam 3 Foam 4 Foam 5
(grams) (grams) (grams) (grams) (grams)
A- B- A- B- A- B- A- B- A- B-
side side side side side side side side side side
NovaCryl 900
Acrylic
18
Solution
=
Citric Acid 45 72 45 36 40
GR- 5M
9
Triton
GenFlo 900 900 900
Xama-7 27 22.5 90 100
Sodium
63 63 63 25.2 70
Bicarbonate
=
Omnapel 900 900 900 1000
YDH 184 135
Hardner CD 20
ABEX 22.5 25
Calcium
65 70
Carbonate
Dioctyl
Adipate
Stanfax 234 35 3
Cabosil 10
Dimethyl
150
Phthalate
5
Table 3 ¨ Encapsulated Crosslinking Agent and Blowing Agent
Encapsulating Encapsulating Encapsulating Encapsulating
Component Materials 1 Materials 2
Materials 3 Materials 4
(grams) (grams) (grams) (grams)
Sodium
14 7 7
Bicarbonate
Citric Acid 14 7 7
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XAMA 20 20 = 20
Melamine
10 10 10
formaldehyde
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Table 4 ¨ One-Part Foam Compositions
Foam 1 Foam 2
Component
(grams) (grams)
NovaCryl 900
Acrylic Solution 90
Citric Acid 36
Encapsulating 64
Materials 1
(Table 3)
Omnapel 900
GR-5M Triton 9 9
Encapsulating
Materials 3 64
(Table 3)
The encapsulating materials are made by well-known methods known to these
skilled in the art of encapsulation, and as such, will not be described
herein.
To form a spray foam using the two-part foam composition of Table 2, the A-
side
components in Table 2 are mixed together and the B-side components are mixed
together.
Mixtures of the A-side components and B-side components are pumped separately
through
hoses to an application gun and combined using a dynamic or static mixer.
Reactions
between the acid and base (to generate bubbles) and reactions between the
functionalized
latex and the crosslinking agent (to support the foam structure) occur when
the foam
components are sprayed from the gun to a desired location, such as cavities.
To form a foamed product using the two-part foam composition of Table 2, the A-
side components in Table 2 are mixed together and the B-side components are
combined
together to form a reaction mixture. The reaction mixture formed of the A-side
components and B-side components is mixed with a propeller blade and poured
into a
mold, where it is left to react. When the foam is hardened (cured), it is
released from the
mold in the shape of a desired product.
To form a spray foam using the one part foam composition of Table 4, the
components in Table 4 are mixed together. The mixtures are pumped through a
hose to an
application gun. It is envisioned that the application gun will be equipped
with a mixing
device that destroys the encapsulating shell containing the blowing agent and
crosslinking
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agent. Reactions between the acid and base blowing agent (to generate bubbles)
and
reactions between the functionalized latex and the crosslinking agent (to
support the foam
structure) occur when the foam components are sprayed from the gun to a
desired location,
such as wall cavities.
The invention of this application has been described above both generically
and
with regard to specific embodiments. Although the invention has been set forth
in what is
believed to be the preferred embodiments, a wide variety of alternatives known
to those of
skill in the art can be selected within the generic disclosure. The invention
is not
otherwise limited, except for the recitation of the claims set forth below.
29
