Note: Descriptions are shown in the official language in which they were submitted.
WO 2012/030941 CA 02809376 2013-02-25PCT/US2011/049939
TITLE OF THE INVENTION
NON-AQUEOUS COLLOIDAL DISPERSION SPRAY FOAMS
BACKGROUND OF THE INVENTION
[0001] The present invention relates generally to spray foams that are used
to fill cavities
and/or cracks, crevices and gaps to enhance the sealing and insulating
properties of buildings
and, more particularly, to non-aqueous-based colloidal dispersion foams useful
at low
temperatures without freezing.
[0002] 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. Spray foams are also used as insulators or sealants for
home walls.
[0003] Two main classes of spray foams are well characterized: polyurethane
(non-
aqueous) and latex (aqueous). 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 reactive
isocyanate ( ¨ N=C=O or
"NCO") functional groups on the molecule. The second component, or "B" side,
contains
nucleophilic reagents, silicone-based surfactants, blowing agents, catalysts,
and/or other
auxiliary agents. The nucleophilic reagents are generally polyols that include
two or more
hydroxyl groups, primary and secondary polyamines, and/or water. Preferably,
mixtures of diols
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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).
[0004] U.S. Patent No. 5,444,099 to Abe et al., U.S. Patent No. 4,945,120 to
Kopp et al.
and U.S. Patent No. 3,984,360 to Galbreath et al. disclose polyurethane spray
foams which may
be capable of being applied at low temperatures. The polyurethane foams in
each these patents
require a polyisocyanate component.
[0005] Known polyurethane spray foams exhibit a number of problems. First,
they
contain high levels of reactive isocyanates, such as 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; and extended
exposure can lead to
serious sequelae, including asthmatic-like reactions and possibly death.
Secondly, residual
polymeric methylene-diphenyl-di-isocyanate (PMDI) that is not used has an NCO
of about 20%
and is considered to be a hazardous waste that 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.
[0006] In this regard, attempts have been made to reduce or eliminate the
presence of
isocyanate in spray foams and/or reduce or eliminate isocyanate emissions by
spray foams into
the atmosphere via the use of latex-based spray foams. Some examples of such
attempts are set
forth below.
[0007] U.S. Patent Publication Nos. 2008/0161430; 2008/0161431; 2008/0161433;
2008/0161432; 2009/0111902; and 2010/0175810 to Korwin-Edson et al. disclose a
room
temperature crosslinked latex foam, such as for filling cavities and crevices.
The foam contains
a first component that includes a functionalized latex (typically the A side)
and a second
component that contains a crosslinking agent (typically the B-side), and
optionally, a non-
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reactive resin (e.g., 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 such as an acid and a base that together form 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.
[0008] U.S. Patent Publication No. 2007/0290074 to Dansizen et al. teaches a
method for
the rapid insulation of expanses. The method utilizes a two-part spray foam
system that may be
applied at low temperatures; however, the chemicals must reach 70-85 F for
proper
performance, and the system utilizes heated spraying hoses to heat the
material for application at
low temperatures.
[0009] 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.
[0010] 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.
[0011] There are problems associated with latex spray foams as well. For
instance, the
processing of spray foams on site may be affected by inclement weather, which
results in
significant economic losses. One serious disadvantage of known spray foam
systems (both latex
and polyurethane) is that they can only be used at ambient temperature above
about 10 C (50
F). If the surface to be insulated is too cold, it rapidly draws the heat of
reaction away from the
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first layer of the foamable reaction mixture sprayed to the surface. This
results not only in an
increased density, but also embrittlement of the foam through incomplete
reaction. The
brittleness of the foam at its initial contact layer is the main reason for
loss of favorable adhesion
properties to the substrate, which the foam system shows when processed on
substrate materials
which are at too low a temperature.
[0012] Another disadvantage with latex spray foams is that the foams
contain water. The
presence of water in the foams results in several problems. First, at low
temperatures, the water
in the spray foams can freeze, thereby disrupting the quality of the foam
itself. Second, the water
often causes the latex to be an open-celled foam of high density. Third,
because the water takes
time to drain or evaporate away, the foam cannot be sprayed to any great
thickness. The foam
cannot support its own weight (due to the water) and it therefore slides down
a wall under its
own weight before it becomes set. Finally, for typical acid-base blowing
agents, which contain
sodium bicarbonate, sodium is present in the final form and promotes
hydrophilicity, which
compounds these water-related problems.
[0013] A third spray foam option is a plastisol. A typical plastisol is an
emulsion that
uses plasticizer in the serum phase. Plastisols, however, require considerable
heat to coagulate
and form a film, since the plasticizer must be absorbed into the lattice to
create a continuous
plastic phase. Temperatures in excess of 200 F are typically required for
plastisols to coagulate.
[0014] Despite these attempts, there remains a need in the art for a spray
foam that is
non-toxic and environmentally friendly and that may be applied at low
temperatures.
SUMMARY OF THE INVENTION
[0015] It is an object of the present invention to provide a non-toxic and
environmentally
friendly, spray foam composition that is capable of being applied at low
temperatures to form a
foamed product, which is also an aspect of the invention. It may be applied as
a two part (A-side
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and B-side) composition or as a single composition with reactants segregated
from one another
until application of the foamable composition.
[0016] Accordingly, in one aspect the invention provides a non-aqueous
foamable
composition comprising:
a solid, coagulatable polymer colloidally dispersed in a non-aqueous,
vaporizable serum
phase, optionally with a surfactant; and
a crosslinking reactant system comprising at least first and second members of
a reactant
pair, each member having multiple reactive groups characterized such that,
upon combination at
or about room temperature, the reactive groups of one member crosslink with
the reactive groups
of at least the other member to form a polymeric crosslinked structure upon
which the polymer
forms a film as it coagulates. Generally the first and second members of the
crosslinking
reactant pair are isolated from one another until combination.
[0017] In another aspect, the invention includes a foamed product
comprising:
a crosslinked structure formed by the reaction of at least first and second
reactants of a
crosslinking reactant system, each having multiple reactive groups
characterized such that, upon
combination at or about room temperature, the reactive groups of one member
crosslink with the
reactive groups of at least the other member to form a polymeric crosslinked
structure;
a polymeric film coagulated on the polymeric crosslinked structure formed; and
a gas generated by vaporization of the non-aqueous serum phase and entrained
by the
polymeric film.
[0018] For both the foamable composition and the foamed product, the
crosslinking
system generally comprises first and second reactant pair members that may be
selected from the
following pairs:
(a) a polyfunctional aziridine and a poly(carboxylic) acid;
(b) a poly(isocyanate) oligomer and a poly(hydroxyl) alcohol; and
(c) a poly(amine) and a poly(epoxy) oligomer.
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[0019] In certain embodiments using a poly(carboxyl) acid, the acid may be a
dry acid
powder without chemically bound water. In certain embodiments, one reactant of
said
crosslinking reactant system may be in the form of a secondary emulsion added
separately to the
non-aqueous serum phase. In certain embodiments, the composition is
substantially free of
water.
[0020] In certain embodiments, the non-aqueous foamable composition further
comprises
a plasticizer. In embodiments with a plasticizer, the plasticizer may be
selected from a benzoate
ester, triethyl citrate, a tributyl citrate, polyethylene glycol, an
octylphenoxypolyethoxyethanol,
butyl benzoate and combinations thereof.
[0021] The non-aqueous foamable composition may be prepared such that the
first and
second reactant members of the crosslinking reactant system are provided in
separate
dispersions, one member being dispersed in the non-aqueous, vaporizable serum
phase along
with the coagulatable polymer (A-side), and the other reactant member being
dispersed in the
plasticizer (B-side). The foamed product is prepared by mixing the separate
dispersions.
[0022] This one aspect of the invention includes a two-part non-aqueous
foamable
composition for forming a foam comprising:
a first component including a lattice phase formed of at least one dry,
coagulatable
polymer in a liquid blowing agent; a multifunctional acid; and a surfactant;
and
a second component including a polyfunctional aziridine crosslinking agent
that
crosslinks at or about room temperature; and a plasticizer, wherein said
plasticizer has no acidic
protons to react with said polyfunctional aziridine crosslinking agent.
[0023] In many embodiments, both the foamable composition and the foamed
product
further comprise a film surfactant. This is generally in addition to colloid
surfactant that
typically comes as part of colloidally dispersed resins useful in the
invention.
[0024] In yet another aspect, the invention provides a method of forming a
foam
comprising:
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combining (a) a solid, coagulatable polymer colloidally dispersed in a non-
aqueous,
vaporizable serum phase, optionally with a surfactant, with (b) at least first
and second members
of a reactant pair of a crosslinking reactant system, each member having
multiple reactive groups
characterized such that, upon combination at or about room temperature, the
reactive groups of
one member crosslink with the reactive groups of at least the other member to
form a polymeric
crosslinked structure, to form (c) a reaction mixture;
applying said reaction mixture to a desired location; and
destabilizing the lattice of the colloidal dispersion, whereby the
coagulatable polymer
begins to coagulate and form a film on the crosslinked structure while said
non-aqueous serum
phase vaporizes to form a gas that is entrained by the polymeric film.
[0025] In certain embodiments, the lattice of the colloidal dispersion is
destabilized by
vaporizing the non-aqueous serum phase to concentrate the colloid and begin
coagulation of the
polymer. The non-aqueous serum phase may be selected to have a boiling point
such that it
vaporizes at ambient application temperature and atmospheric pressure; and the
method then
further comprises pressurizing said colloidal dispersion prior to application
to avoid premature
vaporization. The method may also comprise heating the reaction mixture to a
temperature
above the boiling point of said non-aqueous serum phase to vaporize said non-
aqueous serum
phase.
[0026] As with the foamable compositions described above, crosslinking
structure
reactants may be kept in separate dispersions: as in A-side and B-side
dispersions. Thus, the
method step of combining (a) a solid, colloid-forming polymer dispersed in a
non-aqueous
serum phase, optionally with a surfactant, with (b) first and second reactants
of a crosslinking
reactant system may further comprise mixing an A-side dispersion with a B-side
dispersion,
wherein said A-side dispersion contains the colloid-forming polymer and a one
reactant of the
crosslinking reactant system dispersed in a non-aqueous serum phase, and the B-
side dispersion
contains the other reactant of the crosslinking reactant system dispersed in a
plasticizer.
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[0027] An advantageous feature of these methods is that the reaction mixture
may be
applied at a temperature near or below freezing since there is no water to
freeze and prevent
useful foam formation.
[0028] 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 or barrier to air infiltration by filling cracks
and/or crevices in a building's
roof or walls. Additionally, the foams may be used to form a barrier to seal
cracks or crevices
around doors, windows, electric boxes, and the like.
[0029] The inventive foams do not release any harmful vapors into the air
when applied
or sprayed. As a result, 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.
[0030] It is an advantage of the present invention that the inventive foams
do not contain
the harmful chemicals found in known polyurethane spray foams, such as, for
example,
isocyantes like MDI monomers. Therefore, the foams of the present invention do
not contain
harmful vapors that may cause skin or lung sensitization or generate toxic
waste.
[0031] It is also an advantage that the inventive 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 inventive foams are safe for workers to install and, therefore, can be
used both in the house
renovation market and in occupied houses. Additionally, because there are no
harmful chemicals
in the inventive foams, the foams can be safely disposed without having to
follow any stringent
hazardous waste disposal precautions.
[0032] It is a further advantage of the present invention that the foam could
be dispensed
in a pressurized aerosol form from a can or canister depending on the choice
of blowing
agent/propellant.
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[0033] It is also an advantage of the present invention that the blowing
agent can
vaporize quickly and leave no liquid residue, unlike water, which has to
diffuse slowly.
[0034] The foregoing and other objects, features, and advantages of the
invention will
appear more fully hereinafter from a consideration of the detailed description
that follows.
DETAILED DESCRIPTION OF THE INVENTION
[0035] 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. All references cited herein, including published or
corresponding U.S. or
foreign patent applications, issued U.S. or foreign patents, and any other
references, are each
incorporated by reference in their entireties, including all data, tables,
figures, and text presented
in the cited references.
[0036] The term "R-value" is the commercial unit used to measure the
effectiveness of
thermal insulation and is the reciprocal of its thermal conductance which, for
"slab" materials
having substantially parallel faces, is defined as the rate of flow of thermal
energy (BTU/hr or
Watt) per unit area (square foot = ft2 or square meter =m2) per degree of
temperature difference
(Fahrenheit or Kelvin) across the thickness of the slab material (inches or
meters).
Inconsistencies in the literature sometimes confuse the intrinsic thermal
properties resistivity, r,
(and conductivity, k), with the total material properties resistance, R, (and
conductance, C), the
difference being that the intrinsic properties are defined as being per unit
thickness, whereas
resistance and conductance (often modified by "total") are dependent on the
thickness of the
material, which may or may not be 1 unit. This confusion, compounded by
multiple
measurement systems, produces an array of complex and confusing units the most
common of
which are:
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English Metric/SI units
(inch-pound)
Intrinsic resistivity, r hr*ft2* F K*m
(conductivity, k, is reciprocal) BTU*in W
Total material resistance, R hr*ft2*0F K*m2
(conductance, C, is reciprocal) BTU W
[0037] For ease of comparisons of materials of differing thicknesses, the
building
industry sometimes reports thermal resistance (or conductance) per unit
thickness (e.g. per inch)
effectively converting it to thermal resistivity (conductivity), but retains
the traditional symbol, R
or R-value.
[0038] With regard to dispersions of one phase (the "dispersed" phase) in
another
medium or vehicle (the "continuous" phase or "serum"), the following terms and
definitions may
be used. Dispersions may be categorized on the basis of the physical state of
the continuous
phase or serum, the physical state of the dispersed phase, and the size of the
dispersed phase.
For example, a liquid-in-liquid dispersion of immiscible liquids is an
"emulsion", a gas dispersed
in a solid or a liquid is a "foam", and a solid particle dispersed in a liquid
would be a
"suspension" or a "colloid", depending on the size of the dispersed particle.
Certain dispersions
according to the present invention are colloids, i.e. solids dispersed in
liquids, in which the solid
particle remains dispersed (except upon centrifugation) as a result of
Brownian motion. In
colloids, the dispersed phase is generally of a particle size between about 10-
4 and 10-8 cm, more
typically between about 10-5 and 10-7 cm. Particles larger than this tend to
form suspensions
which will settle under gravity alone; while particles smaller than this tend
to form solutions
which remain dispersed even with centrifugation.
[0039] A "latex" refers to a dispersion of a solid polymer in an aqueous
medium.
Generally the polymer has a Tg less than about 20 C, usually lower than about
10 C, and
typically the particles of polymer are of a size that makes a latex a
colloidal dispersion. Latices
or latexes are plural forms of latex. Paint is an example of a colloidal
latex. "Lattice", on the
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other hand, refers to a 3-dimensional structure that dispersed particles may
exhibit in the
continuous phase based on forces such as electrical charges, hydrogen bonding
or van der Waal's
forces. In many cases the nature and stability of this lattice is dependent on
concentration of
dispersed phase (i.e. how densely packed it is), and on the pH and viscosity
of the continuous
phase, exposure (or not) of functional groups such as by the presence or
absence of a surfactant
or emulsifier.
[0040] The present invention relates to a non-aqueous colloidal dispersion
spray foam
that is suitable for use at low temperatures (e.g. , temperatures below
freezing). The inventive
foams may be used like other foams to seal cracks and crevices of buildings,
such as those
around windows and doors, to improve sealing and insulation properties.
[0041] In one exemplary embodiment, the inventive foam is formed from two
components, namely, a first component or A-side, and a second component or B-
side. In
particular, the A-side of the foam composition includes a colloid-forming
resin or polymer
dispersed a non-aqueous serum phase, typically a volatile blowing agent. Other
components that
may also be included in the A-side include a surfactant, a multifunctional
acid, a crosslinker
catalyst, and/or a nucleating agent. The B-side contains a polyfunctional
aziridine crosslinking
agent and a plasticizer, and optionally a surfactant, a filler, a nucleating
agent, and a non-reactive
resin.
[0042] In the inventive spray foam, a colloidal dispersion is created with a
liquid blowing
agent as the serum phase. When the dispersion reaches the boiling point of the
blowing agent,
the blowing agent vaporizes, thereby concentrating and destabilizing the
lattice structure of the
colloidal polymer, causing the dispersion to coagulate and form a film. At the
same time, the
vaporized serum phase (as a gas) becomes entrained as bubbles in the polymer
matrix to form a
foam. Additionally, the foamable composition contains a crosslinking reactant
system that
creates a crosslinked structure. Without intending to be bound by any
particular theory, it is
believed that the crosslinking reactants form a "skeleton" or "scaffold" to
enhance and maintain
the structure of the foam as the resin is coagulating to form the film. For
best results, it is
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thought to be important that the process of scaffold / crosslinked structure
formation coincide
with the process of film formation. In general, the crosslinking reactant
system comprises at
least first and second reactant members that each have multiple reactive or
functional groups
disposed on backbones. The reactive groups react quickly at or about room
temperature to form
the three dimensional structure on which the film forms. More detail is
provided below.
[0043] In exemplary embodiments, the foams of the present invention, as
well as the
components thereof, meet certain performance properties, or Fitness for Use
("FFU") criteria,
both chemical and physical. In particular, desired criteria or FFUs that the
inventive foam
should meet are set forth in the table below:
Chemical Criteria Physical Criteria
= The foam should adhere to various = The foam weight should be between
about
materials such as wood, metal, 0.5 and about 30.0 pounds per cubic
foot
concrete and plastic = The foam should be fluid enough to be
= The chemical constituents should be as sprayed either at room temperature or
by
safe as possible. If a hazardous heating (viscosity of <10,000 cP at a
high
chemical is used, it should not be shear rate)
introduced or atomized into the air = The foam should not sag or fall in the
cavity
where it can be inhaled = The foam should fill in cracks and
crevices
= The foam may be chemically foamed or be used to coat the cavity with an
air
through the use of a blowing agent or barrier
it may be mechanically foamed with a = Ideally, the cell structure of the foam
(closed
gas vs. open) should be a mixture of both a
= The installer of the foam should be closed and open cell structure to
provide
able to work with the material without appropriate material properties to
achieve
any specialized personal protective the other FFUs
equipment ("PPE"), such as a = The foam should have a thermal
resistance
breathing apparatus, although (R-value) of at least 3.0 Fft2h/BTU
per inch
chemical goggles, dust mask, and = The foam should be non-sagging and non-
gloves are acceptable dripping (i.e., fire retardant) during
a fire
= The foam should not lend itself to = The foam should not corrode metal
objects
molding or fungus growth (ASTM such as screws, nails, electrical
boxes, and
C1338) the like
= The foam should not contain a food
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source for insects or rodents = Air infiltration should be negligible
(ASTM
= There should be a minimum shelf life E283-04) (spec 0.4 cfm/ sq ft)
of the un-reacted constituents of 9 = Water vapor infiltration should be
greater
months. then 1 perm or 5.72x10-8 g/Pa-s-m2
= The foam should have low or no odor.
Colloid-forming, coagulatable polymer
[0044] As discussed above, the foamable composition according to the
present invention
includes a coagulatable polymer or resin that forms a colloid when dispersed
in a non-aqueous
serum phase. As implied by the name, this polymer is in solid, particulate
form and of
sufficiently fine particle size to be colloidally dispersed in the serum. Such
polymers are
routinely prepared by suppliers for aqueous dispersions or latexes, and may
even be called latex
resins even when in a particulate or powder form. Suitable polymers may be
prepared by any of
the well known processes, including but not limited to suspension
polymerization and emulsion
polymerization as described in the literature, for example, Rodriguez, F.,
PRINCIPLES OF
POLYMER Sys ILMS, 2d Ed. McGraw Hill, 1982, pages 105-125, incorporated herein
by
reference. The polymers may and usually do include a "colloid surfactant" as
part of their
formulation, which enhances their formation of stable lattices in dispersions.
Suitable polymers
are available from a wide variety of suppliers, including Dow Chemical, BASF,
and others.
[0045] Non-limiting examples of suitable polymers for use in the
inventive compositions
include acetic acid ethenyl ester polymers; polyvinyl chloride (PVC);
polyvinylidene chloride;
acrylics; neoprene; styrene-butadiene rubber (SBR); nitrile rubbers (e.g.,
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
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rubbers; polyacrylate rubbers including, for example, copolymers of isooctyl
acrylate and acrylic
acid; polyesters; polyether esters; polyvinylidene chloride; polyvinyl ethers;
polyurethanes; and
combinations thereof. These polymers and polymers like these undergo a process
of "drying" or
"coagulating" to form a polymeric film as is well known in the art.
[0046] The colloid-forming polymer(s) may be present in an amount from about
20 to
about 65 percent by weight of the foamable composition, and in exemplary
embodiments, in an
amount from about 25 to about 50 percent by weight, or from about 25 to about
40 percent be
weight. In two part dispersions, the colloid-forming polymer(s) may be present
in an amount
from about 40 to about 75 percent, or from about 50 to about 70 percent by
weight of the
dispersion in which it is contained.
[0047] The polymer is capable of coagulating upon itself to form a film. In
some
embodiments, the polymer may be a functionalized polymer, i.e. resins having
reactive
functional groups that additionally crosslink to enhance coagulation. Such
functional groups
may include, for example, carboxyl, hydroxyl, amino, epoxy and other moieties
known to be
reactive. Importantly, the functional groups may often interact with the
crosslinking reactant
system described below, and the degree to which the resin is functionalized
may be important in
defining the properties of the resultant foams. Too little crosslinking or too
much crosslinking
and the foams lose some of their elastomeric properties.
Non-aqueous serum phase
[0048] The polymer, described above, is dispersed in a non-aqueous serum
phase, a
liquid and preferably a vaporizable or volatile liquid. By "volatile" is meant
that the serum has a
boiling point that ranges from about 0 F to about 80 F, more likely from
about 15 F to about
60 F, so that it can be vaporized to a gas phase upon atmospheric application
in a wide range of
climates, possibly without applying further heat to cause the vaporization.
Boiling point is
known to be dependent on both temperature and pressure, so that lower boiling
serums can be
kept from premature boiling by pressurization, if desired. Alternatively,
somewhat higher
boiling points may be used without pressurization if the serum is heated upon
application. Both
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pressurization and heat may be employed. The gas phase generated in this
manner becomes an
integral part of the foam as it becomes entrained in pockets or cells bounded
by the film of the
coagulating polymer.
[0049] Ideally, the serum phase may be a typical blowing agent, provided they
meet the
"volatile" criteria. Suitable, non-limiting examples of blowing agents that
may be used as the
serum phase include C1 to C9 aliphatic hydrocarbons (e.g., methane, ethane,
propane, n-butane,
cyclopentane, isobutane, n-pentane, isopentane, and neopentane), C1 to C3
aliphatic alcohols
(e.g., methanol, ethanol, n-propanol, and isopropanol), HFC blowing agents
(e.g., 1,1,1,3,3-
pentafluoropropane (HFC-245fa), 1,1,1,4,4,4 -hexafluorobutane (HFC-356mff),
1,1,1,3,3-
pentafluorobutane (HFC-365mfc), 1,1,1,2-tetrafluoroethane (HFC-134a), 1,1-
difluoroethane
(HFC-152a), 1,1,1,3,3,3-hexafluoropropane (HFC-236fa), 1,1,1,3,3-
pentafluorobutane (HFC-
365mfc)); and nitrogen. It is to be appreciated that any of the blowing agents
for use in the
foamable composition can be used singly or in any combination thereof.
Eliminating an
acid/base blowing agent system utilizing sodium bicarbonate also eliminates
sodium from the
final foam. Sodium can be detrimental to the foam as it is hydrophilic in
nature. The blowing
agent may be present in an amount from about 10 to about 40 percent by weight
of the
composition, and in exemplary embodiments, in an amount from about 15 to about
30 percent by
weight. In two part dispersions, the blowing agent may be present in an amount
from about 25 to
about 50 percent, or from about 30 to about 40 percent by weight of the
dispersion in which it is
contained.
Crosslinking reactant system
[0050] The next component of the inventive foam composition is a crosslinking
reactant
system. This system may involve more than two reactants, but binary systems
are simple and
sufficient, so the embodiments described will include two reactants as members
of a reactant
pair. The reactant members contain backbones that may be solely hydrocarbon or
hydrocarbon
with heteroatoms; and the backbones generally contain at least 3 atoms, but
may contain many
more, and may be formed as monomers or as oligomers of repeating units. Spaced
along these
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backbones, the first and second reactant members have at least two and
preferably three or more
reactive or functional groups that are capable of crosslinking at or about
room temperature. The
exact nature and composition of the backbone is not critical; it merely needs
to provide covalent
attachment points for the reactive functional groups, preferably with some
spacing so as to
provide rotational degrees of freedom about the bonds and avoid steric
hindrance of adjacent
reactive groups.
[0051] The reactive or functional crosslinking groups are provided in pairs,
the first
reactant generally containing the one member of the pair and the second
reactant containing the
other member of the pair. The members of the pair react to crosslink at or
about room
temperature and without the need for addition of significant heat or
activation energy. For this
purpose, heat added by an application device to vaporize a serum phase blowing
agent is not
considered significant heat. Consequently, the first and second reactants are
isolated prior to use
in an application of the foamable composition. The first and second reactants
are isolated from
one another in some embodiments by providing them in two separate and distinct
dispersions, as
is typical in the case of polyurethane and latex spray foams: an A-side and a
B-side.
Alternatively, they may be isolated by encapsulation or protection of the
reactive groups, which
encapsulation or protection is removed during the application process. These
mechanisms are
described in more detail below.
[0052] Pairs of reactant members and their reactive functional groups
suitable for the
crosslinking reactant system include but are not limited to:
(a) a polyfunctional aziridine and a polyfunctional (carboxylic) acid;
(b) a polyfunctional (isocyanate) oligomer and a polyfunctional (hydroxyl)
alcohol; and
(c) a polyfunctional (amine) and a polyfunctional (epoxy) oligomer.
Polyfunctional in this context refers to at least two (difunctional), three
(trifunctional) or higher
level of reactive groups per backbone molecule. Three or more reactive groups
per backbone
molecule are considered polyfunctional or multifunctional. Each pair member of
the
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crosslinking reactant system will have an "effective equivalent" number of
functional groups that
may be estimated theoretically and determined empirically. The "effective
equivalent" number
of functional groups is often less than the actual number due to the
inevitable steric hindrance of
some functional groups in larger molecules. In general, it is desirable to
provide the first reactant
and second reactant in equal "effective equivalents" i.e. in a 1:1 molar ratio
considering moles of
available or "effective" functional groups. However, this 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. When functionalized polymers are employed, the ratio may
ideally be
adjusted to add more equivalents of whichever reactant tends to react with
functional groups of
the polymer.
[0053] Polyfunctional aziridines are most commonly found in di- and tri-
functional
compounds. Suitable examples include XAMA('-7 and XAMA('-2, tri-functional
aziridines
available from Bayer Corporation; PZ-33, an ethylene imine-based tri-
functional polyaziridine
available from PolyAziridine, LLC; Crosslinker CX-100, a polyfunctional
aziridine available
from DSM NeoResins; and XC-103, a trifunctional aziridine available from
Zealchem. Because
these aziridines are highly reactive with acidic protons, it is desirable to
ensure that no water or
other ionizable species that produce free protons are available in dispersions
with the aziridines.
These polyfunctional aziridines may be used singly or in combination, and may
be present in an
amount from about 2 to about 25 percent by weight of the dry foam composition,
preferably in
an amount from about 3 to about 10 percent by weight. In two part dispersions,
the
polyfunctional aziridines may be present in an amount from about 10 to about
25 percent, or
from about 15 to about 18 percent by weight of the dispersion in which it is
contained.
[0054] In exemplary embodiments, the polyfunctional acid is a dry acid
powder without
chemically bound water. Non-exclusive examples of polyfunctional acids
include, but are not
limited to, polyacrylic acid, 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
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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
polyfunctional
acid may be monomeric (as are many described above) or polymeric in nature.
Urethane
oligomers have been prepared having pendant functional carboxyl groups. In
exemplary
embodiments, the acid is a polyacrylic acid. These polyfunctional acids may be
used singly or in
combination, and may be present in an amount from about 1.0 to about 10
percent by weight of
the dry foam composition, and in exemplary embodiments, in an amount from
about 3.0 to about
7.0 percent by weight. In two part dispersions, the multifunctional acid may
be present in an
amount from about 2 to about 10 percent, or from about 4 to about 6 percent by
weight of the
dispersion in which it is contained.
[0055] In some embodiments, the multifunctional acid may be a secondary
emulsion that
is added to the composition separately. For example, if the multifunctional
acid is not miscible
in the non-aqueous serum phase, then the acid may be introduced into the
foamable composition
as a stable emulsion (e.g. water in oil) within the serum phase. The
multifunctional acid may be
placed into an emulsion with the assistance of a surfactant, such as the
surfactants described
herein.
[0056] Another pair of reactants that can form scaffolding is: polyfunctional
(isocyanate)
oligomer and a polyfunctional (hydroxyl) alcohol or polyols. These reactants
are similar to those
found in typical polyurethane foams and are well known in the art to crosslink
at or about room
temperature. See, e.g. Szycher's Handbook of Polyurethanes, CRC Press, Boca
Raton, FL 1999,
pp. 3-1 to 3-39 in particular, which are incorporated herein by reference.
[0057] However, there are two key distinctions in the present invention.
First, a reduced
amount of isocyanate is required since the purpose is merely to create a
crosslinked scaffold
structure, not form the complete resin film. Second, the isocyanates are pre-
polymerized to form
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oligomers to minimize the toxicity of isocyanate groups. Prepolymers combine
multiple
isocyanate molecules (e.g. from 2 to about 5 or more) and in this way the NCO
content can be
reduced from about 16 -30% by weight (as in monomers) to about 1 to 14% by
partial
polymerization. This NCO content range still affords suitable reactivity with
the hydroxyl
groups of polyols to generate a three dimensional scaffold and has suitable
viscosity required for
flowability. Useful isocyanate prepolymers include, e.g. Dow EchelonTM pre
polymers, Bayer
BaytecTM and/or Huntsman pre-polymers.
[0058] Polyols useful as the second reactant member of the isocyanate-polyol
pair are
discussed in Ionescu, M., Chemistry and Technology of Polyols for
Polyurethane, Smithers
Rapra Press, 2008, incorporated herein by reference. Polyols used to produce
polyurethanes are
typically in the molecular weight range of 400 to 5000 Daltons and may include
the classes of
polyethers and polyesters. In general, low molecular weight polyols create
hard plastics while
high molecular weight polyols create flexible elastomers. Some important
illustrative polyols
include glycerine, poly(propylene oxide) glycol, castor oil, poly(ethylene
adipate),
polycaprolactone, polytetra methylene ether glycol (PTMEG), polycarbonate and
VoranolTM (a
polyether triol available from Dow Chemical).
[0059] Some examples of isocyanate prepolymers available in the market and
corresponding polyols are given in the table below:
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Supplier Product Polyol base Iso type % NCO
Bayer Baytec ME-050 PTMEG MDI* 5.9
Bayer Baytec ME-120 PTMEG MDI 12
Bayer Baytec MP-080 Polyether MDI 8.0
Bayer Baytec MP-090 Polyether MDI 9.0
Bayer Baytec MS-041 Polyester MDI 4.1
Bayer Baytec MP-090 Polyester MDI 9.0
Dow Echelon MP-100 MDI 10.2
Dow Echelon MP-104 MDI 16
Dow Echelon MC-400 MDI 10.2
*MDI = methylene-diphenyl-di-isocyanate
[0060] Another pair of reactants that can form a crosslinked, "scaffold-
like" structure is:
polyfunctional (amine) and a polyfunctional (epoxy) oligomer. See, eg.
Rozenberg, B.A.,
Kinetics, thermodynamics and mechanism of reactions of epoxy oligomers with
amines, in
ADVANCES IN POLYMER SCIENCE, 1986, Volume 75/1986; pp 113-165, incorporated
herein by
reference. The most common epoxy used in industry is diglycidyl ether of
bisphenol A
(DGEBA). This epoxy is sold by Dow Chemical under the trade name DER 331. Some
common amine reactants for epoxy would be as follows:
Supplier Chemical
Dow Diethyl triamine (DETA)
Dow Triethylene triamine (TETA)
Dow Amino ethyl piperazine (AEP)
Dow Polyethylene polyamine
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Plasticizer
[0061] According to some embodiments of the invention, the foamable
composition may
include a plasticizer. Plasticizers are known to lower the glass transition
temperature (Tg) of
polymers and may be used to facilitate softening of the polymer colloid
particles, leading to
coagulation to the film. Useful plasticizers have been found in the di/tri-
carboxylic ester class
and the benzoate ester class, although other classes may be suitable. Examples
of suitable
plasticizers include butyl benzoate, Benzoflex 2088 (a benzoate ester
plasticizer available from
Genovique Specialties), Benzoflex LA-705 (a benzoate ester plasticizer
available from
Genovique Specialties), Citroflex 2 (a triethyl citrate available from
Vertellus Specialties), and
Citroflex 4 (a tributyl citrate available from Vertellus Specialties). In
exemplary
embodiments, the plasticizer is a benzoate ester or a citric acid ester.
[0062] In embodiments employing separate A-side and B-side dispersions, the
plasticizer
may be additionally useful as a vehicle or medium for B-side dispersions, thus
diluting one of the
crosslinking reactants. For example, diluting a polyfunctional aziridine
provides several
advantages. First, the concentration of polyfunctional aziridine is lowered,
reducing health risks
to those in contact with it. Polyfunctional aziridine contains about 0.001% of
ethyleneimine,
which is a very reactive moiety, and in theory, will react with the very small
level of acid
impurities or water content that may be present in other components of the
composition. Second,
the viscosity of the B-side is reduced when the polyfunctional crosslinking
reactant is diluted
with the plasticizer. As a result, the components of the B-side can be better
mixed with the A-
side to form a more homogeneous mixture. Finally, the plasticizer adds volume
to the B-side,
allowing the two parts of the foam composition to be delivered in ratios that
more closely
approach 1:1, and thus they can be delivered with known spray equipment,
thereby negating the
need for any specialized equipment.
[0063] The plasticizer, when used, is generally present in an amount from
about 2 to
about 20 percent by weight of the dry foam composition, and in exemplary
embodiments, in an
amount from about 2 to about 15 percent by weight. In two part dispersions,
the plasticizer may
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be present in an amount from about 10 to about 80 percent, or from about 20 to
about 60 percent
by weight of the dispersion in which it is contained.
[0064] Additionally, the presence of the plasticizer permits for the
inclusion of other
solid materials that may add functionality and/or cost savings to the final
foamed product. For
instance, coagulation agents, fillers (e.g., calcium carbonate and
wollastonite fibers), nucleating
agents (e.g., talc), and/or foaming agents (e.g., sodium bicarbonate) can be
included in the B-side
of the foamable composition. The inclusion of fillers such as wollastonite
fibers helps with the
stability of the cell structure after the cells have been formed. It is to be
appreciated that when
the plasticizer and other components in the B-side do not contain any acidic
protons, the B-side
is stable for extended periods of time, such as up to at least six months or
more.
Surfactants, colloid and film
[0065] As noted above, the solid colloid-forming polymer may optionally
contain a
"colloid surfactant" that interfaces between polymer and serum to help
stabilize the polymer
lattice in dispersions. In some cases, it may be desirable to add additional
surfactant and/or a
secondary "film surfactant" to the foamable composition. The film surfactant,
when used, may
be the same or different since it serves a different purpose. Instead of
stabilizing the polymer
lattice, the film surfactant interfaces between polymer and the entrained gas
phase and is used to
stabilize the film formation during the foaming process and to provide a high
surface activity for
the nucleation and stabilization of the foam cells. Useful surfactants for
lattice and/or film
formation 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 (e.g., Triton X200K available from Cognis), octylphenol ethoxylate
(e.g., Triton
X705 available from Cognis), disodium N-octadecyl sulfosuccinamate (e.g.,
Aerosol 18P
available from Cytec), octylphenol polyethoxylates (e.g., Triton X110
available from Cognis),
alpha olefin sulfonate, sodium lauryl sulfates (e.g., Stanfax 234 and Stanfax
234LCP from Para-
Chemicals), ammonium laureth sulfates (e.g., Stanfax 1012 and Stanfax 969(3)
from Para-
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Chemicals), ammonium lauryl ether sulfates (e.g., Stanfax 1045(2) from Para-
Chemicals),
sodium laureth sulfates (e.g., Stanfax 1022(2) and Stanfax (1023(3) from Para-
Chemicals),
sodium sulfosuccinimate (e.g., Stanfax 318 from Para-Chemicals), and aliphatic
ethoxylate
nonionic surfactants (e.g., ABEX available from Rhodia). The choice of a
particular surfactant
may be guided by ionic preference, HLB and the specific properties of the
adjoining medium
(serum or gas phase), but remains largely an empirical choice. The surfactant
may be present in
the foamable composition in an amount from about 0.05 to about 2.0 percent by
weight of the A-
side composition, and in exemplary embodiments, in an amount from about 0.4 to
about 1.0
percent by weight.
Other Optional Ingredients
[0066] As noted, the foamable composition may contain other optional
ingredients, in
either or both of an A-side and B-side when separate dispersions are used.
Such optional
ingredients may include a nucleating agent, coagulation agents, foam
promoters, opacifiers,
accelerators, foam stabilizers, dyes (e.g., diazo or benzimidazolone family of
organic dyes), color
indicators, gelling agents, flame retardants, biocides, fungicides,
algaecides, fillers (aluminum
tri-hydroxide (ATH)), and/or 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. Other optional additives can be between 0
and 10% of the final
formulation.
[0067] Suitable, non-limiting examples of nucleating agents that may be used
in the
spray foam of the present invention are talc, precipitated calcium carbonate,
and silica. The
nucleating agent may be present in an amount from about 1.0 to about 10.0
percent by weight of
the dry foam composition, and in exemplary embodiments, in an amount from
about 1.0 to about
5.0 percent by weight.
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[0068] Coagulation agents facilitate the coagulation process to help
establish the film,
generally from 0 to 3% by weight. Suitable, non-limiting examples of
coagulation agents that
may be used in the spray foam of the present invention are diethylene glycol
butyl ether,
dipropylene glycol n-butyl ether, isopropyl alcohol, and ethyl alcohol.
[0069] It is to be appreciated that the inventive foam and composition are
desirably free
of water. However, small amounts (e.g., 2-3%) of water may be brought into the
system, such as
though added components, as is discussed in detail below. However, the water
is in such a small
amount that it does not disrupt the foam process or create other problems
heretofore associated
with the inclusion or presence of water in foamable compositions. The water-
free or
substantially water-free foam composition as recited herein enables the foam
to be sprayed to a
greater thickness than water-containing foams. For instance, in known latex
foams, the weight
of the water prevents the foam from being able to support itself. Thus, the
foam, after being
sprayed, will slide down a vertical surface under its own weight. Also, the
lack of water in the
inventive foams permits the foam to be closed celled with a relatively low
density. In some
exemplary embodiments, the density of the foam may be between about 0.5 and
about 20 pounds
per cubic foot, or from about 15 to about 18 pounds per cubic foot. In
addition, the water present
in known latex foams can freeze, thereby destroying the structural integrity
of the foam. Further,
the lack of water in the inventive foam composition permits the foam to be
sprayed at low
temperatures, including below-freezing temperatures.
[0070] Much has already been described relating to the use of two-part
foamable
compositions as a means to isolate the first and second reactants of the
crosslinking reactant
system. But exemplary isolated dispersions with multiple and optional
ingredients are set forth
in the examples and in the table below.
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WO 2012/030941 PCT/US2011/049939
A-side B-side
suggested Coagulatable, colloid-forming polymer Polyfunctional aziridine
Poly(carboxylic) acid Plasticizer serum
Non-aqueous blowing agent serum
Film surfactant
optional Wollastonite Additional resin
Talc or calcium carbonate Coagulation agent
In use, the A side is mixed with the B side in a A:B ratio ranging from about
1:1 to about 5:1 to
form a foam product. The relative weight ratio depends in part on the nature
of the
polyfunctional crosslinking reactants, (i.e. how much function per weight) and
the desired end-
use application.
[0071] Alternatively, a one-part foamable composition may be prepared
using
encapsulation as a means to isolate the first and second reactants of the
crosslinking reactant
system, as well as any additional components that would prematurely react,
such as acidic
protons in the case of aziridines or functional groups if present on a polymer
resin. In general,
the reactive components are separated or isolated by means of encapsulation in
a protective shell
or coating as described in more detail in US Patent Publication 2008/0161430,
incorporated
herein by reference. The protective shell may be a wax or gelatin that can be
melted at the time
of the application of the foam. 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. Optionally, the encapsulating
material may be a low
melting, semi-crystalline, super-cooled polymer. Only one member of any
reactant pair need be
encapsulate and, with judicious choices, a minimum number of reagents may need
encapsulation.
The reactants are released at time of application by means of heat, shear,
sonication,
photoactivation or other technique to disrupt the encapsulating shell.
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Methods and Process
[0072] To form a two-part spray foam of the present invention, the
components of the A-
side and the components of the B-side may be delivered through separate lines
into a spray
device, such as an impingement-type spray gun. Depending on choice of the
serum phase, the
gun may be heated to a temperature above the boiling point of the blowing
agent. It is to be
appreciated that the heat being supplied to the mixture may be derived from
external sources
such as built-in heaters, a heated hose, or a heated gun; or from internal
sources, such as heat of
exothermic reactions. 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 and heat up
within the gun.
[0073] Upon contact, the first and second reactants of the crosslinking
reactant system
quickly begin to crosslink, forming a three dimensional, covalently
crosslinked structure
believed to resemble a scaffold or skeleton. If a functionalized polymer is
used, reactions may
occur between it and the first and /or second reactants as well. This scaffold-
like structure
supports the foam while the polymer is coagulating and hardening. The
previously fluid/viscous
foam material is substantially immobilized by the internal scaffold-structure,
which prevents the
foam from collapsing before it coagulates. It is hypothesized that the use of
a multifunctional
acid advantageously provides for a more flexible backbone in the polymeric
structure.
[0074] Because the components are under pressure inside the gun, the blowing
agent
does not vaporize. However, as the mixture exits the gun and enters into
atmospheric pressure,
the blowing agent begins to vaporize just as the scaffold is forming. As the
continuous serum
phase vaporizes, the lattice particles necessarily become more concentrated
until a point at which
they destabilize, coagulate and form a film on the growing crosslinked
structure. The very action
of the serum phase turning to vapor forces the lattice particles together,
while at the same time, it
supplies the gas phase for entrainment in the polymer to from the foam.
[0075] It is to be appreciated that the crosslinking is important for
capturing the gas
bubbles in their original, fine structure before they can coalesce and escape
the foam. A fine
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WO 2012/030941 CA 02809376 2013-02-25PCT/US2011/049939
foam structure is more desirable and more beneficial than a coarse foam
structure in order to
achieve a high structural, thermal, and air sealing performance. Additionally,
if present, the
functional groups on the colloid-forming polymer quickly crosslink and build
strength in the
foam, and permit the foam to withstand the force of gravity when it is placed,
for example, in a
vertical wall cavity during application. As noted earlier, the degree of
crosslinking between a
functionalized resin and members of the crosslinking reactant system may also
have an impact
on the elastomeric and other properties of the foam.
[0076] The final foamed product becomes cured to the touch within about 1-3
minutes
after application, typically within about 2 minutes; and hardens within about
1 to 6 minutes. In
foams intended for use as insulating materials, the resulting resistance to
heat transfer, or R-
value, is desirably from about 3.5 to about 8 per inch. In certain uses, the
foamed product has an
integral skin that restricts the passage of air but permits the passage of
water vapor.
[0077] In use, the inventive foams may be sprayed into a closed cavity where
it expands
to seal any open spaces. In another embodiment, the foams of the present
invention may be used
to seal the insulative cavities of a building such as a house and minimize or
eliminate air flow
into the insulative cavities and effectively seal the building. The foams of
the present invention
may also be used to insulate buildings such as homes from temperature
fluctuations outside of
the building's envelope. Additionally, the foams of the present invention may
serve as a sealant
to air infiltration by filling cracks and/or crevices in a building's roof or
walls, around doors,
windows, electric boxes, and the like. The foam may also be applied to seal
holes in walls and
floors. The foams may serve both as a conductive and a convective thermal
barrier. In
exemplary embodiments, the application of the foam is a continuous spray
process.
[0078] The inventive foam can also be used in applications where extruded
polystyrene
foam forms the envelope of a building. Although polystyrene foams are good
insulators, they
have a tendency to buckle and create gaps and/or crevices. Similarly, when a
fibrous board is
used as the sheathing, gaps and crevices naturally occur, such as at the
interfaces between the
sheathing and framing due to the natural warping and curvature of fibrous
products. The
27
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inventive foams may be sprayed into these crevices and gaps as a sealant to
reduce or eliminate
air infiltration into the insulative cavity.
[0079] Additionally, the inventive foams may be applied to the faces of the
studs (or the
face of the framing of the building) to obtain a superior seal against air
infiltration. In particular,
the inventive foam is sprayed or otherwise applied to the face of the studs as
described above and
drywall is attached to the surface of the studs in any known manner.
Desirably, the foam is
sprayed onto the stud faces prior to the insertion of the insulation into the
building cavities. It is
to be understood that the foam may be sprayed to the faces of the studs with
or without applying
the foam around the interior boundary of the insulative cavities. The
elastomeric foam acts as a
gasket seal between the stud face and the drywall. In addition, the foam
assists in leveling and
smoothing the stud surface to which the drywall will be attached.
[0080] The spray foam composition of the present invention has several
benefits. One
important benefit of the inventive foam composition is that the foam may be
applied in cold
conditions, including temperatures approaching about 20 F, without adversely
affecting the
nature of the foam. Moreover, the spray foam of the present invention contains
no water or, if
water is present (such as, for example, in an additive), the water is present
in only a small
amount. The lack of water (or small amount of water) in the spray foam means
that water not is
present in the foam in an amount such that it would freeze at low temperature
and disrupt the
quality of the foam. A further benefit resulting from the lack of water in the
spray foam of the
present invention is that the blowing agent can vaporize quickly and leave no
residue, like water,
which diffuses very slowly over time.
[0081] Another advantage of the foams of the present invention is the safe
installation of
the foam into cavities. Because the foams do not release any harmful vapors
into the air when
applied or sprayed, 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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[0082] 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 and/or animals (e.g.
renovation
market). Existing 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.
[0083] It is also an advantage of the spray foam that, unlike known 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.
[0084] 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.
EXAMPLES
[0085] Example 1. The following example illustrates how to make some
exemplary
two-part embodiments of the inventive foam. Table 1 sets forth a list of
components, given as
weight percent present in the A-side and B-side respectively of five (A-E) two-
part foam
compositions.
Table 1- Components
A B C D E
SIDE A Pct. Pct. Pct. Pct. Pct.
Solid Polymer
DLP - 2141 Dow Chemical 65 65
DLP - 2001 Dow Chemical 65 65
DLP - 211 Dow Chemical 65
Surfactant
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A B C D E
Triton GR5M Cognis 1 1 1
1
Stanfax 234 Para-Chemicals 1
Serum Phase/ Blowing Agent
HFC-245(fa) Honeywell 19 19 19 13
11
Water --- 5 5 5 5
5
Polyfunctional First Reactant
Aquaset 1676 (poly acid) Dow Chemical 5 5 5
Glycerine (poly hydroxyl) --- 5 5 5
Voranol 230-238 Polyether Dow Chemical 14
16
triol (238 OH number)
Catalyst
PMDETA (N,N,N',N',N"-PENTAMETHYLDIETHYLENETRIAMINE)* 1
1
DMCHA (N,N-Dimethylcyclohexylamine)** 1
1
A-side total (%) 100 100 100 100
100
SIDE B A B C D
E
Serum/ Plasticizer Pct. Pct. Pct.
Pct. Pct.
Benzoflex 2088 Genovique 61 10
Specialties
Citroflex 4 VertellusC) 61
10
Specialties
Citroflex 2 VertellusC) 61
Specialties
Polyfunctional Second Reactant
PZ-33 (poly Aziridine) PolyAziridine, 17 17 17
PLLC
Echelon MP-100 Dow Chemical 90
Polyurethane Prepolymer
(10.2% NCO)
Baytec MP-90 isocyanate Bayer Chemical
90
terminated polyether
prepolymer (9 % NCO)
Filler
Calcium Carbonate 10.7 10.7 10.7
Thickening Agent
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A
Thixatrol Max Elementis 1.3 1.3 1.3
Specialties
Vansil HR 1500 RT Vanderbilt 10 10 10
Co, Inc.
B-side total (%) 100 100 100 100 100
Ratio A:B 4:1 4:1 4:1 1:1 1:1
* Blowing catalyst
** Gelling catalyst
[0086] The A-side and the B-side of each formulation (A-E) are mixed
together in a
weight ratio (A:B) as indicated in the table (either 4:1 or 1:1) to form a
foam product.
[0087] Example 2. The following example illustrates how varying the
degree of
crosslinking between a functionalized resin and the crosslinking reactant
system impacts the
elastomeric properties of the foam.
[0088] [insert new data]
[0089] The invention of this application has been described above both
generically and
with regard to specific embodiments, although 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.
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