U.S. patent number RE31,757 [Application Number 06/443,877] was granted by the patent office on 1984-12-04 for composition and a method for controlling reaction pressures during the foaming process resulting in an easily flame retarded foam-in place insulation.
This patent grant is currently assigned to Patrick J. Crehan, Richard J. Fricke. Invention is credited to Richard B. Kennedy.
United States Patent |
RE31,757 |
Kennedy |
December 4, 1984 |
Composition and a method for controlling reaction pressures during
the foaming process resulting in an easily flame retarded foam-in
place insulation
Abstract
A low reactive pressure flame-retardant polyurethane foam made
by reacting together a polymeric isocyanate, a polyol, an aqueous
solution of a carbohydrate, calcium acid phosphate, sodium aluminum
sulfate, sodium bicarbonate, and a flame retardant. A blowing agent
may be present.
Inventors: |
Kennedy; Richard B.
(Ridgefield, CT) |
Assignee: |
Crehan; Patrick J. (Ridgefield,
CT)
Fricke; Richard J. (Ridgefield, CT)
|
Family
ID: |
26859087 |
Appl.
No.: |
06/443,877 |
Filed: |
November 23, 1982 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
162821 |
Jun 25, 1980 |
04291129 |
Sep 22, 1981 |
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Current U.S.
Class: |
521/103; 521/106;
521/107; 521/108; 521/109.1; 521/119; 521/120; 521/123 |
Current CPC
Class: |
C08G
18/6484 (20130101); C08J 9/0066 (20130101); C08J
9/0038 (20130101); C08J 2375/04 (20130101) |
Current International
Class: |
C08J
9/00 (20060101); C08G 18/00 (20060101); C08G
18/64 (20060101); C08G 018/14 () |
Field of
Search: |
;521/103,106,107,108,109,119,120,123 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Welsh; Maurice J.
Attorney, Agent or Firm: Wyatt, Gerber, Shoup, Scobey &
Badie
Claims
What is claimed is:
1. A low reactive pressure flame-retardant polyurethane foam made
by reacting together a .[.polymeric isocyanate.].
.Iadd.polyisocyanate, .Iaddend.a conventional polyol, a surfactant,
.[.a blowing agent.]. and an aqueous solution .Iadd.or slurry
.Iaddend.of a carbohydrate, calcium acid phosphate, sodium aluminum
sulfate, sodium bicarbonate, and flame retardant.
2. The polyurethane foam according to .[.claim 1.]. .Iadd.claims 1,
15, 16 or 17 .Iaddend.wherein the carbohydrate is selected from the
group consisting of cornstarch, corn syrup, dextrose, sucrose, and
molasses.
3. The polyurethane foam according to .[.claim 2.]. .Iadd.claims 1,
15, 16 or 17 .Iaddend.wherein the carbohydrate is cornstarch.
4. The polyurethane foam according to .[.claim 2.]. .Iadd.claims 1,
15, 16 or 17 .Iaddend.wherein the carbohydrate is corn syrup.
5. The polyurethane foam according to .[.claim 1 including.].
.Iadd.claims 16 or 17 wherein the blowing agent is .Iaddend.a
hypochlorite salt selected from the group consisting of calcium
hypochlorite and sodium hypochlorite.
6. The polyurethane foam according to .[.claim 1.]. .Iadd.claims 1,
15, 16 or 17 .Iaddend.wherein the flame retardant is selected from
the group consisting of sodium chloride, calcium chloride, alkali
metal borates, tri-cresyl phosphate, tris(2-chloroethyl) phosphate,
tris(chloropropyl) phosphate, O,O-diethyl-N,N-bis(2-hydroxyethyl)
aminomethyl phosphate, antimony oxide, alumina, and antimony
oxychloride.
7. The polyurethane foam according to .[.claim 1.]. .Iadd.claims 15
or 16 .Iaddend.wherein the blowing agent is selected from the group
consisting of methylene chloride, ethylenetrichloride,
trichloromonofluoromethane, dichlorodefluoromethane, and
dichlorotetrafluoroethane.
8. The polyurethane foam according to .[.claim 1.]. .Iadd.claims 1,
15, 16 or 17 .Iaddend.including a catalyst.
9. A method for making a flame-retardant polyurethane foam
comprising:
a. .[.dissolving.]. .Iadd.mixing .Iaddend.a carbohydrate, calcium
acid phosphate, sodium aluminum sulfate, sodium bicarbonate,
surfactant, and a flame retardant selected from the group
consisting of sodium chloride, calcium chloride, alkali metal
borates, tri-cresyl phosphate, tris(2-chloroethyl phosphate),
tris(chloropropyl)-phosphonate,
O,O-diethyl-N,N-bis-(2-hydroxyethyl)aminoethyl phosphate, antimony
oxide, alumina, and antimony ocychloride, to form an aqueous
solution; .Iadd.or slurry .Iaddend.
b. mixing the aqueous solution .Iadd.or scurry .Iaddend.with
.[.polyether.]. .Iadd.conventional .Iaddend.polyol;
c. .[.adding to.]. .Iadd.mixing with .Iaddend.the polyol-aqueous
solution .Iadd.or slurry .Iaddend.mixture a .[.polymer
isocyanate.]. .Iadd.polyisocyanate .Iaddend.and .[.mixing.].;
d. allowing the mixture to .[.faom.]. .Iadd.foam.Iaddend..
10. The method of .[.claim 9.]. .Iadd.claims 9, 13, 25 or 26
.Iaddend.wherein the carbohydrate is selected from the group
consisting of cornstarch, corn syrup, dextrose, sucrose and
molasses.
11. The method of .[.claim 10.]. .Iadd.claims 9, 13,25 or 26
.Iaddend.wherein the carbohydrate is cornstarch.
12. The method of .[.claim 10.]. .Iadd.claims 9, 13, 25 or 26
.Iaddend.wherein the carbohydrate is corn syrup.
13. The method of claim 9 wherein a blowing agent is added to the
polyol-aqueous solution .Iadd.or slurry .Iaddend.mixture.
14. The method of .[.claim 9.]. .Iadd.claims 9, 13, 25 or 26
.Iaddend.wherein a catalyst is present in the aqueous solution
.Iadd.or slurry .Iaddend.of step (a). .Iadd.15. A polyurethane foam
according to claim 1 wherein the polyisocyanate is polymeric
isocyanate. .Iaddend. .Iadd.16. The polyurethane foam according to
claim 1 wherein a blowing
agent is incorporated in the reaction mixture. .Iaddend. .Iadd.17.
The polyurethane foam according to claim 1 wherein the
polyisocyanate is a polymeric isocyanate and a blowing agent is
incorporated in the reaction mixture. .Iaddend. .Iadd.18. The low
reactive polyurethane foam made by reacting together a
polyisocyanate, a conventional polyol, a surfactant, and an aqueous
solution or slurry of a carbohydrate, calcium acid phosphate,
sodium aluminum sulfate, and sodium bicarbonate. .Iaddend.
.Iadd.19. The polyurethane foam according to claim 18 wherein the
polyisocyanate is a polymeric isocyanate. .Iaddend. .Iadd.20. The
polyurethane foam according to claim 19 wherein a blowing agent is
incorporated in the reaction mixture. .Iaddend. .Iadd.21. The
polyurethane foam according to claim 18 wherein the polyisocyanate
is a polymeric isocyanate and a blowing agent is incorporated in
the reaction mixture. .Iaddend. .Iadd.22. The polyurethane foam
according to claims 18, 19, 20 or 21 wherein the carbohydrate is
selected from the group consisting of cornstarch, corn syrup,
dextrose, sucrose and molasses. .Iaddend. .Iadd.23. The
polyurethane foam according to claims 18, 19, 20 or 21 wherein the
carbohydrate is cornstarch. .Iaddend. .Iadd.24. The polyurethane
foam according to claims 18, 19, 20 or 21 wherein the carbohydrate
is corn syrup. .Iaddend. .Iadd.25. The polyurethane foam according
to claims 20 or 21 wherein the blowing agent is a hypochlorite salt
selected from the group consisting of calcium hypochlorite and
sodium hypochlorite. .Iaddend. .Iadd.26. The method of claim 9
wherein the polyisocyanate is a polymeric isocyanate. .Iaddend.
.Iadd.27. The method of claim 9 wherein the polyisocyanate is a
polymeric isocyanate and a blowing agent is incorporated in the
polyol aqueous solution or slurry. .Iaddend. .Iadd.28. A method for
making a polyurethane foam comprising:
a. mixing a carbohydrate, calcium acid phosphate, sodium aluminum
sulfate, sodium bicarbonate and surfactant to form an aqueous
solution or slurry;
b. mixing the aqueous solution or slurry with a conventional
polyol;
c. mixing with the polyol-aqueous mixture a polyisocyanate and;
d. allowing the mixture to foam. .Iaddend. .Iadd.29. The method of
claim 28 wherein the polyisocyanate is a polymeric isocyanate.
.Iaddend. .Iadd.30. The method of claim 28 wherein a blowing agent
is added to the polyol-aqueous solution or slurry. .Iaddend.
.Iadd.31. The method of claim 28 wherein the polyisocyanate is a
polymeric isocyanate and a blowing agent is incorporated in the
polyol aqueous solution or slurry. .Iaddend. .Iadd.32. The method
of claims 28, 29, 30 or 31 wherein the carbohydrate is selected
from the group consisting of cornstarch, corn syrup, dextrose,
sucrose and molasses. .Iaddend. .Iadd.33. The method of claims 28,
29, 30 or 31 wherein the carbohydrate is cornstarch. .Iaddend.
.Iadd.34. The method of claims 28, 29, 30 or 31 wherein the
carbohydrate is corn syrup. .Iaddend. .Iadd.35. The method of
claims 13, 30 or 31 wherein the blowing agent is selected from the
group consisting of methylene chloride, ethylenetrichloride,
trichloromonofluoromethane, dichlorodifluoromethane and
dichlorotetrafluoroethane. .Iaddend. .Iadd.36. The method of claims
28, 29, 30 or 31 wherein a catalyst is present in the aqueous
solution or slurry of step (a)..Iaddend.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a composition and a method for
controlling reaction pressures during the foaming process resulting
in an easily flame retarded foam-in place insulation.
The present invention is the subject of an Invention Disclosure
Document filed Feb. 4, 1980, Disclosure Document No. 087883.
Rigid plastic foams have been widely utilized as thermal insulating
materials, light construction materials, and floating materials
because of their excellent properties. However, since they are
composed of plastic materials they can provide a substantial fuel
contribution, cause rapid flame spread and produce a great deal of
noxious smoke on thermal decomposition when burned or heated to an
elevated temperature, thus leading to their limited use as
construction material.
With the present invention in conserving heating fuel, many
existing buildings are having additional insulation added to their
structures, and newly constructed buildings are including more
insulation then was formerly used.
A most commonly used type of insulation for existing structures is
ureaformaldehyde foam, which is foamed in place between the outside
wall and the inside wall of the structure. Unfortunately, the
ureaformaldehyde foam can break down releasing noxious formaldehyde
fumes. Some jurisdictions have already prohibited the use of
ureaformaldehyde foams in buildings because of the potential
continual long term release of formaldehyde vapors.
Another type of material used for insulation is polyurethane foam.
However, polyurethane foam provides a substantial fuel
contribution, spreads flame rapidly, and releases toxic gases
including but not by way of limitation gases such as carbon
monoxide carbon dioxide, and hydrogen cyanide when burned.
Additionally, polyurethane foam generally disintegrates when
burned. Polyurethane foam cannot be used to retrofit existing
structures with in-wall insulation due to the high reaction
pressures generated during the foaming process which can be
sufficient to separate the wallboard from the wall studs.
Rigid polyurethane foams are generally prepared by reacting an
organic polyisocyanate with a polyol in the presence of a foaming
agent surfactant and catalyst. In order to reduce the cost of
preparing these foams, efforts have been made to employ starch as a
polyol reactant in the preparation of urethane foams. The use of
starch directly has been unsatisfactory because of the poor
physical properties of the foam which results. Oxyalkylated starch
yields satisfactory foams, but the direct oxyalkylation of starch
results in degradation or decomposition of the starch and a product
which is not uniform in chemical or physical properties.
A satisfactory process for utilizing starch as a component in the
preparation of polyurethane foams is disclosed in U.S. Pat. No.
3,277,213. In this process, starch is added to a polyhydric alcohol
containing at least two hydroxyl groups in a proportion equivalent
to at least 0.5 mole of the alcohol per mole of glucose unit weight
of starch in the presence of an acid catalyst. The resulting
mixture is then oxyalkylated to yield a polyether polyol suitable
for use in preparating polyurethane foams of excellent physical
properties. Although it is generally recognized that the presence
of high proportions of nitrogen, phosphorus, and/or chlorine atoms
enhances the flame resistance of urethane foams, present techniques
for adding these components to urethane foams are not entirely
satisfactory.
U.S. Pat. No. 3,674,717, discloses a process for preparing
flame-retardant polyurethane foams by admixing starch with
phosphoric acid at an elevated temperature and oxyethylating the
resulting mixture to yield a starch-phosphorus-based polyether
useful as a reactant in the preparation of urethane foams with
flame-retardant properties.
Another method of making flame retardant polyurethane foams, as
disclosed in U.S. Pat. No. 3,658,731, is by reacting dry whey or
lactose and whey or yeast protein with a polyisocyanate in the
presence of dimethylsulfoxide.
SUMMARY OF THE INVENTION
The present invention relates to a composition and method for
foaming in place an easily flame retarded, inexpensive, low
reactive pressure polyurethane foam containing untreated starch and
other chemicals.
It has been found that polyurethane foams prepared in accordance
with the present invention possess flame retardant properties and
retain their structural integrity when exposed to flame. Upon
exposure to heat or flame, the foam neither disintegrates nor loses
structural integrity.
The foam composition is based on a polyurethane made from a
polymeric isocyanate, compatible polyether polyol, and an aqueous
slurry or solution of an untreated carbohydrate such as cornstarch
corn syrup, dextrose, sucrose, molasses, and the like. The foam
composition additionally contains calcium acid phosphate, sodium
aluminum sulfate, sodium bicarbonate, and a commercially available
flame retardant chemical such as sodium chloride, calcium chloride,
borax, an alkali metal borate, tricresyl phosphate, tris
(2-chloroethyl) phosphate, tris (chloropropyl) phosphate,
0,0-diethyl-N, N-bis-(2-hydroxyethyl) aminomethyl phosphonate,
metal oxides and chlorides such as antimony oxide, alumina and
antimony oxychloride. A polyurethane catalyst may also be included
in the composition.
The principal reaction involved occurs between the polyisocyanate
and the polyhydroxy compound to yield a polyurethane polymer. The
heat generated by the exothermic polymerization reaction causes the
foaming agent, such as a low boiling hydrocarbon, to vaporize,
whereby the vapors become entrapped to form the desired cellular
structure. Alternatively, the mixture can be foamed by vigorous
agitation to incorporate air into the polymeric system. Another
alternative is a combination aqueous solution of sodium
bicarbonate, potassium tartarate, and either calcium hypochlorite
or sodium hypochlorite which can be added to the reaction mixture
to function as a blowing agent.
Isocyanates which can be used in the present invention include the
following compounds: tolylene-2,4-diisocyanate, polymethylene
polyphenyl isocyanate, tolylene-2,6-diisocyanate, and a mixture
thereof, either crude or purified diphenylmethane
4,4'-diisocyanate, 3-methyldiphenylmethane-4,4'-diisocyanate, m-
and p-phenylenediisocyanate, and naphthalene-1,5-diisocyanate.
Either crude or pure isocyanates can be used. A prepolymer having
isocyanate groups at the ends which can be prepared by the reaction
of an excess of polyisocyanate with a lesser amount of a polyol
having more than two hydroxyl groups per molecule can also be used
in this invention. The combined use of more than two
polyisocyanates is also possible.
Polyols which can be used in this invention include polyether
polyols prepared by combining one or more alkylene oxides (such as
ethylene oxide, propylene oxide, and butylene oxide) with a
reaction initiator (such as water, ethylene glycol, glycerine,
trimethylol-propane, pentaerythritol, ethylenediamine, sorbitol,
and sucrose). Another type of polyol that can be used is a
polyester polyol having hydroxyl groups at the ends prepared by a
condensation reaction of one or more polyhydroxyl alcohols, such as
ethylene glycol or trimethylol-propane, with one or more
polycarboxylic acids, such as adipic, phthalic, or succinic acids.
Another example of a polyol useful in the present invention is a
polymer polyol which can be prepared by graft polymerizing
polyacrylonitrile to an aliphatic polyol.
Water is used with the carbohydrate in the present invention in
order to provide a carrier for the carbohydrates and inorganic
salts. The amount of water used is kept to a minimum to prevent
"sighing", i.e., the collapse of the foam, as well as to aid in the
reduction of the pressure of the foaming reaction.
The total amount of water used in the syrup in the present
composition should be from about one part of water to four parts of
syrup to about four parts of water to about one part of syrup, all
parts by weight. The preferred ratio of water to syrup is 1:1.
By increasing the amount of polyol, the foam density is reduced.
Additionally, with an increase in the amount of polyol, the
reaction temperatures and pressures increase. In a typical polyol
isocyanate mix, the reaction pressure is such that the foam causes
wallboard to separate from the wall studs if the reaction mixture
is foamed in place for insulation. In the present invention, if an
excess of polyol is used, the reaction pressure increases, but not
to a level which would separate wallboard from the wall studs.
As the amount of polyol in the reaction mixture is reduced, the
cure time is extended and the temperatures and pressures of the
reaction are reduced. The resulting foam is generally denser.
To prepare the syrup for use with the polyol, preferably from 1 to
6 ounces of cornstarch or other carbohydrate are mixed with 10
ounces of water and from 10-30 milligrams each of calcium acid
phosphate, sodium aluminum sulfate, and sodium bicarbonate. There
is no upper limit to the amount of carbohydrate that can be used in
the present invention, other than viscosity limitations, as the
cornstarch increases the viscosity of the mixture. Where corn syrup
is used in the mixture, the corn syrup provides approximately 9% by
weight of additional water to the mixture.
The amount of water in the composition, which also acts as a
blowing agent for the foam, results in the restricted evolution of
carbon dioxide, which is generated by the reaction of water with
isocyanate. For the purpose of adjusting the density of the rigid
foams, low boiling hydrocarbons, carbon dioxide, or
chlorofluoroalkanes can be used as a blowing agent in conjunction
with the water. Chlorofluoroalkanes which can be used in the
present invention include those generally used in the preparation
of polyurethane foams. Suitable hydrocarbons and haloalkanes should
be chemically inert toward the polyisocyanate and have a boiling
point less than 100.degree. C., preferably from -50.degree. C. to
70.degree. C. Suitable haloalkanes include methylene chloride,
ethylenetrichloride, trichloromonofluoromethane,
dichlorodifluoromethane, dichlorotetrafluoroethane, and
dibromomonofluoroalkane.
A catalyst may be used to form trimers of the isocyanate as well as
catalysts to form urethane bonds and/or those to form urea bonds
and/or buiret bonds. Some catalysts which act in the formation
reactions of trimers of isocyanate also show catalytic activity in
the formation of urethane-, urea-, and/or buiret bonds, and vice
versa. These catalysts cannot appropriately be classified in
different categories, but they may be classified according to their
most predominant catalytic tendencies, respectively, as is adopted
here.
Catalysts which act to form trimers of isocyanate in the present
invention include 2, 4, 6-tris(dimethylaminomethyl)phenol, o- and
p-dimethylaminomethylphenol,
N,N',N"-tris(dimethylaminopropyl)-sym-hexahydrotriazine,
benzyltrimethylammonium methoxide, alkali metal salts of carboxylic
acids (such as potassium acetate, potassium propionate, potassium
octanate, and potassium benzoate), alkali metal salts of weak acids
other than carboxylic acids (such as, for example, potassium
arsenate, sodium benzenesulfonate, potassium p-nitrophenolate),
inorganic bases (such as sodium hydroxide and potassium hydroxide),
sodium methoxide, salts of lead, cobalt, iron, cadmium, and
chromium.
Catalysts which are liquid at room temperature may be used as is
and mixed with the polyols, and those which are solids may be used
in the form of a solution prepared beforehand in dimethylformamide
or dimethylsulfoxide, or mixed in water with the carbohydrate.
Catalysts which act in forming the urethane bonds, urea bonds, and
buiret bond are common to those which are used generally in the
preparation of polyurethane foams. These catalysts can be
conveniently classified into tertiary amines and organometallic
compounds. The tertiary amines include triethylamine,
triethanolamine, diethanoamine, monethanolamine,
dimethylmonoethanolamine, triethylinediamine,
tetramethylpropanediamine, tetramethyl-1,3-butanediamine, and
pentamethyldiethyltriamine. Organometallic compounds include, for
example, dibutyltin dilaurate, dibutyl tin diacetate, bityl tin
dicaprylate, and stannous octoate. Of course, these catalysts can
be used either alone or in combination. The amounts to be used are
in accordance with their reactivity.
Surfactants are used to stabilize the foam during the foaming
process. Surfactants which can be used in the present invention
include; Dow Corning (R) 193 a.k.a DC 193, which is a
nonhydrolizable silicone glycol copolymer. Union Carbide's (R) L
5420 is another nonhydrolyzable silicone glycol copolymer which may
be used.
To make the foam according to the present invention, the inorganic
salts, corn starch, flame retardant compounds, surfactants, and
catalysts are dissolved in a minimum amount of water and mixed
withe the carbohydrate syrup. The carbohydrate syrup containing the
aforementioned ingredients is then added to the polyol and
thoroughly mixed. Already mixed carbohydrate syrup and polyol
solution is then added to the isocyanate and thoroughly mixed. The
resulting mixture, which is liquid, is then introduced into a mold
or behind a wall to form a flame retarded insulating foam. The
ingredients can be combined in a commercially available mixing gun
for introduction into the mold.
In the present invention, the preferred ratio of isocyanate, polyol
and carbohydrate syrup mix are 1 part by weight polyol, 1 part by
weight isocyanate and 1 part by weight carbohydrate syrup mix.
Variations in the ratios effect the reaction time, density, yield
and quality of the foam.
The carbohydrate syrup is a mixture of water, corn starch, and/or
corn syrup. The only limits to variation of the mix relate to
viscosity limitations. This mixture may also contain surfactants
and catalyst to speed the reaction and reduce the possibility of
collapse during the foaming process.
The inorganic salts are present in small amounts, generally about
10 to 100 milligrams each of calcium hydrogen phosphate, aluminum
sulfate, and sodium bicarbonate per ounce of isocyanate.
The flame retardant compounds are mixed with the carbohydrate syrup
for addition to the reaction mixture. These compounds are used in
amounts necessary to provide flame retardancy to the resulting
polyurethane foam, generally in amounts ranging from 20 to 200
milligrams per ounce of polyol.
The order of addition of ingredients to produce the foam of the
present invention is necessary to ensure the proper reaction
conditions. The foam of the present invention, while conventional
urethane foams, does not normally produce unacceptable high
reaction pressures or temperatures.
Typical polyurethane foam formulas composed of polyol and
isocyanate result in a reaction which severely limits "off gassing"
causing high reactive pressures. When the carbohydrate syrup is
mixed with the polyol, which is then added to the isocyanate,
additional "off gassing" occurs resulting in reduced reactive
pressure. The foam yield is increased with the addition of the
carbohydrate syrup.
Where the reduction of the amount or the elimination of the
conventional blowing agent is desired, a combination of sodium acid
phosphate and potassium acid tartarate, calcium bicarbonate, corn
starch, and either calcium hypochlorite or sodium hypochlorite may
be dissolved in the carbohydrate syrup. In this process, from 10 to
20 parts by weight of hypochlorite and from 20 to 40 parts by
weight of the aforementioned additives are used per 100 parts by
weight of polyol.
When a conventional blowing agent is used, in combination with
either calcium or sodium hypochlorite, two distinct consecutive
reactions appear to occur. The first reaction appears to be the
same as a conventional foaming reaction containing a typical
blowing agent, with some rising of the foam. The rising of the foam
stops, the foam appears to boil, and then the foam rises a second
time.
Halogenated hydrocarbons containing freon routinely used as a
blowing agent in urethane foam are currently being scrutinized by
The Federal Environmental Protection Agency and useage limitations
may be imposed.
A Freon-free foam can be made by a slight modification of the
carbohydrate syrup.
To make foam under this invention which would contain no freon
blowing agent, the amount of calcium or sodium hypochlorite is
increased as are the amounts of surfactant and catalyst resulting
in a CO.sub.2 -blown foam of good quality.
Upon foaming, the mixture provides an insulating flame-resistant
rigid foam having closed cells and a skin on the outside of the
foam. These closed cells and skin act as a vapor barrier for the
foam, so that normally no additional vapor barrier is necessary to
provide a superior insulating material. Certain potential
applications may be practical without the addition of a flame
retardant. A low reactive pressure non-flame retarded foam may also
be produced under this invention.
TYPICAL FORMULATIONS OF THIS INVENTION
EXAMPLE I
Ten ounces polymethylene polyphenyl isocyanate (Mobay MONDUR
MR.RTM.) was mixed with ten ounces of a solution of water and syrup
containing four ounces of cornstarch (Corn Products Starch 3005);
30 milligrams calcium acid phosphate; 30 milligrams sodium aluminum
sulfate; 30 milligrams sodium bicarbonate; 60 milligrams sodium
chloride, one ounce surfactant and 1/4 ounce polyurethane. The
above ingredients were mixed in a mixing tank of suitable capacity
with an electric mixer. To this mixture was added ten ounces of
polyether polyol containing surfactant, polyurethane, and blowing
agent, and the entire mixture blended. The final mixture was poured
into a wall cavity, where it foamed and provided excellent
permanent bonding to all the surfaces of the wall cavity.
EXAMPLE II
A rigid polyurethane foam was prepared using calcium bicarbonate
and sodium hypochlorite as a blowing agent.
Ten ounces of (Mobay MONDUR MR.RTM.) polymethylene polyphenyl
isocyanate was mixed with ten ounces of water and syrup solution
containing three ounces of cornstarch (Corn Products Starch 3005);
30 milligrms calcium acid phosphate; 30 milligrams sodium aluminum
sulfate; 30 milligrams sodium bicarbonate; 50 milligrams calcium
chloride; one ounce calcium hypochlorite; one ounce surfactant and
1/4 ounce catalyst. To this is added ten ounces of Mobay E
9214.RTM. polyether polyol; one-half ounce DC 193 Silicone
Surfactant (nonhydrobyzable silicone glycol copolymer), and
one-tenth ounce DABCO 33LV .RTM. catalyst, and the resulting
mixture was blended thoroughly. The mix was then poured into a wall
cavity and allowed to foam to fill the wall cavity.
EXAMPLE III
Ten ounces of polymethylene polyphenyl isocyanate was mixed with
ten ounces of corn syrup; 20 milligrams calcium acid phosphate; 20
milligrams sodium aluminum sulfate; 100 milligrams sodium
bicarbonate; 50 milligrams calcium chloride, one-quarter ounce
calcium hypochlorite; one ounce surfactant and 1/4 ounce catalyst.
To this mixture was added ten ounces of polyether polyol prepared
by adding ethylene oxide and propylene oxide to glycerine and one
gram of fluorotrichloromethane. The material was introduced into a
wall cavity, whereupon the material provided a rigid, low-density
foam.
In order to introduce the foamable mixture of the present invention
into a wall cavity, the following equipment can be used:
1. A mixing tank to blend the ingredients of the formulation. The
mixing tank ideally possesses means to cool or heat the mix.
2. A high pressure, low volume metering transfer pump to measure
and transfer the chemical mix from the mixing tank to the wall
cavity.
3. An entrance post-surplus foam collector. This assembly slides
into the hole drilled into the interior wall board or external
sheathing of the wall. This assembly is to direct the flow of
liquid downward, collect the surplus foam, and protect the finished
wall surfaces from "foam staining."
In addition, the composition of the present invention can be foamed
in standard, commercially available urethane foaming equipment
which employs a mixing head and pumps the foam into the wall
cavity.
* * * * *