U.S. patent application number 09/122132 was filed with the patent office on 2002-01-31 for flame resistant rigid polyurethane foams blown with hydrofluorocarbons.
Invention is credited to BURNS, STEVEN B., JONES, PATRICIA A., SINGH, SACHCHIDA N..
Application Number | 20020013379 09/122132 |
Document ID | / |
Family ID | 21985970 |
Filed Date | 2002-01-31 |
United States Patent
Application |
20020013379 |
Kind Code |
A1 |
SINGH, SACHCHIDA N. ; et
al. |
January 31, 2002 |
FLAME RESISTANT RIGID POLYURETHANE FOAMS BLOWN WITH
HYDROFLUOROCARBONS
Abstract
Rigid polyurethane foams having improved flame resistance are
disclosed. The foams are prepared from a composition containing (a)
an isocyanate, (b) an isocyanate reactive composition containing an
aromatic polyester polyol, (c) an organo phosphorus compound and
(d) a C.sub.1 to C.sub.4 hydrofluorocarbon.
Inventors: |
SINGH, SACHCHIDA N.;
(SICKLERVILLE, NJ) ; BURNS, STEVEN B.; (WESTMONT,
NJ) ; JONES, PATRICIA A.; (BEAR, DE) |
Correspondence
Address: |
PATENT & TRADEMARK ADMINISTRATOR
Huntsman Polyurethanes
Law Department
286 Mantua Grove Road
West Deptford
NJ
08066-1732
US
|
Family ID: |
21985970 |
Appl. No.: |
09/122132 |
Filed: |
July 24, 1998 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60053701 |
Jul 25, 1997 |
|
|
|
Current U.S.
Class: |
521/174 ;
521/131; 521/168; 521/172; 521/173 |
Current CPC
Class: |
C08J 9/146 20130101;
C08G 18/4208 20130101; C08J 9/0038 20130101; C08G 18/482 20130101;
C08J 2203/142 20130101; C08J 2205/10 20130101; C08J 2375/04
20130101; C08G 2110/005 20210101; C08G 2110/0025 20210101 |
Class at
Publication: |
521/174 ;
521/131; 521/168; 521/172; 521/173 |
International
Class: |
C08J 009/00; C08G
018/10 |
Claims
What is claimed is:
1. A foam forming composition comprising: a) an organic isocyanate,
b) an isocyanate reactive composition containing at least 40% by
weight based on the total weight of the isocyanate reactive
composition of an aromatic polyester polyol having an average
functionality of less than 3, c) a C.sub.1 to C.sub.4
hydrofluorocarbon blowing agent, and d) an organic phosphorus
compound.
2. A foam forming composition, as claimed in claim 1 wherein the
organic isocyanate is polyphenylene polymethylene
polyisocyanate.
3. A foam forming composition as claimed in claim 2 wherein the
isocyanate contains diphenyl methane diisocyanate in an amount
equal to from about 15% to about 42% by weight based on the total
weight of the isocyanate.
4. A foam forming composition as claimed in claim 1 wherein the
amount of isocyanate is equal to from about 30% to about 75% by
weight based on the total weight of the foam forming
composition.
5. A foam forming composition as claimed in claim 1 wherein the
aromatic polyester polyol in the isocyanate reactive composition is
prepared by reaction of an aromatic polycarboxylic acid and a
polyhydric alcohol.
6. A foam forming composition as claimed in claim 1 wherein the
isocyanate reactive composition also contains a compound selected
from the group consisting of polyether polyols, aliphatic polyester
polyols, hydrogen-terminated polythioesters, polyamides, polyester
amides, polycarbonates, polyacetals, polyolefins and
polysiloxanes.
7. A foam forming composition as claimed in claim 1 wherein the
C.sub.1 to C.sub.4 hydrofluorocarbon blowing agent is selected from
the group consisting of difluoromethane, trifluoromethane,
1,1-difluoroethane, 1,1,1-trifluroethane,
1,1,1,2-tetrafluoroethane, pentafluoroethane, any isomer of
pentafluoropropane, any isomer of heptafluoropropane, any isomer of
pentafluorobutane, 1,1,1,4,4,4-hexafluorobutane,
1,1,1,3,3-pentafluoropropane and 1,1,1,3,3-pentaflurobutane.
8. A foam forming composition as claimed in claim 7 wherein the
hydrofluorocarbon blowing agent is
1,1,1,3,3-pentafluoropropane.
9. A foam forming composition as claimed in claim 1 wherein the
composition contains water as an additional blowing agent.
10. A foam forming composition as claimed in claim 1 wherein the
organophosphorus compound is selected from the group consisting of
phosphates, phosphites, phosphonates, polyphosphates,
polyphosphites, polyphosphonates, and ammonium polyphosphate.
11. A foam forming composition as claimed in claim 1 wherein the
organophosphorus compound is a phosphate compound having the
following formula: 4where R.sup.1, R.sup.2 and R.sup.3 are
independently selected from alkyl, halogen substituted alkyl, aryl,
halogen substituted aryl and cycloalkyl groups.
12. A foam forming composition as claimed in claim 11 wherein
R.sup.1, R.sup.2 and R.sup.3 are independently selected from
C.sub.1-C.sub.12 alkyl, C.sub.1-C.sub.12 halogen substituted alkyl,
phenyl, cresyl, halogen substituted phenyl and C.sub.5-C.sub.10
cycloalkyl groups.
13. A foam forming composition as claimed in claim 11 wherein
R.sup.1, R.sup.2 and R.sup.3 are C.sub.1 to C.sub.8 alkyl or
C.sub.1 to C.sub.8 halogen substituted alkyl.
14. A foam forming composition as claimed in claim 11 wherein
R.sup.1, R.sup.2 and R.sup.3 are C.sub.1 to C.sub.4 alkyl or
C.sub.1 to C.sub.4 halogen substituted alkyl.
15. A foam forming composition as claimed in claim 11 wherein
R.sup.1, R.sup.2 and R.sup.3 are phenyl.
16. A foam forming composition as claimed in claim 1 wherein the
organophosphorus compound is a phosphite compound having the
following formula: 5where R.sup.1, R.sup.2 and R.sup.3 are
independently selected from H, alkyl, halogen substituted alkyl,
aryl, halogen substituted aryl and cycloalkyl groups.
17. A foam forming composition as claimed in claim 16 wherein
R.sup.1, R.sup.2 and R.sup.3 are independently selected from
C.sub.1-C.sub.12 alkyl, C.sub.1-C.sub.12 halogen substituted alkyl,
phenyl, cresyl, halogen substituted phenyl and
C.sub.5-C.sub.10cycloalkyl groups.
18. A foam forming composition as claimed in claim 16 wherein
R.sup.1, R.sup.2 and R.sup.3 are independently selected from
C.sub.1-C.sub.8 alkyl or C.sub.1-C.sub.8 halogen substituted
alkyl.
19. A foam forming composition as claimed in claim 16 wherein
R.sup.1, R.sup.2 and R.sup.3 are independently selected from
C.sub.1-C.sub.4 halogen substituted alkyl.
20. A foam forming composition as claimed in claim 16 wherein
R.sup.1, R.sup.2 and R.sup.3 are phenyl.
21. A foam forming composition as claimed in claim 1 wherein the
organophosphorus compound is a phosphonate compound having the
following formula: 6where R.sup.1, R.sup.2 and R.sup.3 are
independently selected from alkyl, aryl, halogen substituted alkyl,
aryl, halogen substituted aryl and cycloalkyl groups.
22. A foam forming composition as claimed is claim 21 wherein
R.sup.1, R.sup.2 and R.sup.3 are independently selected from
C.sub.1-C.sub.12 alkyl, C.sub.1-C.sub.12 halogen substituted alkyl,
phenyl, cresyl, halogen substituted phenyl and C.sub.5-C.sub.10
cycloalkyl groups.
23. A foam forming composition as claimed in claim 21 wherein
R.sup.1, R.sup.2 and R.sup.3 are independently selected from
C.sub.1-C.sub.8 alkyl or C.sub.1-C.sub.8 halogen substituted
alkyl.
24. A foaming forming composition as claimed in claim 21 wherein
R.sup.1, R.sup.2 and R.sup.3 are independently selected from
C.sub.1-C.sub.4 alkyl or C.sub.1-C.sub.4 halogen substituted
alkyl.
25. A foam forming composition as claimed in claim 21 wherein
R.sup.1, R.sup.2 and R.sup.3 are phenyl.
26. A foam forming composition as claimed in claim 1 wherein the
organophosphorus compound contains at least one isocyanate reactive
hydrogen group selected from hydroxyl, amino and thio.
27. A foam forming composition as claimed in claim 1 wherein the
amount of organophospohorus compound used is such that the amount
of phosphorous in the composition is equal to from about 0.01 to
about 2.5% by weight, based on the total weight of the
composition.
28. A foam forming composition as claimed in claim 27 wherein the
amount of organophosphorous compound used is such that the amount
of phosphorous in the composition is from about 0.025 to about 1.5%
by weight, based on the total weight of the composition.
29. A foam forming composition as claimed in claim 27 wherein the
amount of organophosphorous compound used is such that the amount
of phosphorous in the composition is from about 0.05 to about 1.0%
by weight, based on the total weight of the composition.
30. A rigid polyurethane foam having a density of from 1.2 to 4.2
lb/cu ft prepared from the composition of claim 1.
Description
FIELD OF THE INVENTION
[0001] The present invention is directed to foams having improved
flame resistance. In particular, the foams of the invention are
closed celled rigid polyurethane or urethane-modified
polyisocyanurate.
BACKGROUND OF THE INVENTION
[0002] A critical factor in the large scale commercial acceptance
of rigid polyurethane foams in the building insulation industry has
been their ability to provide a good balance of properties. Rigid
polyurethane foams are known to provide outstanding thermal
insulation, excellent fire performance and superior structural
properties, all at reasonably low density. Such rigid foams are (in
general) prepared by reacting the appropriate polyisocyanate and
isocyanate-reactive compound in the presence of a blowing agent.
Chlorofluorocarbon blowing agents (CFCs) such as CFC-11
(CCl.sub.3F) and CFC-12 (CCl.sub.2F.sub.2) have been the most
commercially important blowing agents primarily because of their
good thermal insulating properties and low or non-flammability. Use
of such blowing agents has been a key reason for the good balance
of properties of rigid polyurethane foams. Recently, CFCs have been
associated with the declining ozone concentration in the earth's
atmosphere and their use has been severely restricted.
Hydrochlorofluorocarbons, especially HCFC-141b (CCl.sub.2FCH.sub.3)
and HCFC-22 (CHClF.sub.2) have become the interim solution in many
applications, once again due to their good thermal insulating
properties and low or non-flammability. HCFCs still have an ozone
depletion potential and their use is under constant scrutiny. The
production and use of HCFC-141b is presently scheduled to end by
the year 2003 in the USA.
[0003] Such environmental concerns have led to a need to develop
reaction systems which utilize blowing agent(s) having a zero ozone
depletion potential while retaining the good balance of properties
for which rigid polyurethane foams are known. A class of materials
which have been investigated as such blowing agents are
hydrofluorocarbons (HFCs), for example:
1,1,1,3,3-pentafluoropropane (HFC-245fa);
1,1,1,3,3-pentafluorobutane (HFC-365mfc); 1,1,1,2-tetrafluoroethane
(HFC-134a); 1,1-difluoroethane (HFC-152a). There are numerous
patents and literature references on the use of HFC's as blowing
agents for rigid polyurethane foam. The use of such materials is
disclosed, e.g., in U.S. Pat. No. 5,496,866 (Bayer); U.S. Pat. No.
5,461,084 (Bayer); U.S. Pat. No. 4,997,706 (Dow); U.S. Pat. No.
5,430,071 (BASF); U.S. Pat. No. 5,444,101 (ICI). Although HFCs are
environmentally more acceptable than CFCs and HCFCs, they are
inferior in fire properties. The polyurethane foams prepared using
the HFC blowing agent must have good fire properties while
retaining the good thermal and structural properties, all at
densities comparable to those possible with CFC and HCFC blowing
agents. Fire properties are especially important for rigid
polyurethane foams used in the building industry as they must meet
strict fire resistance codes.
[0004] At present, hydrofluorocarbons and hydrocarbons are the two
leading classes of materials that are being evaluated by the rigid
foam industry as zero ozone depletion potential (ODP) blowing
agents. Neither of these two materials has all the attributes of an
"ideal" blowing agent. For example, the global warming potentials
of HFCs are high (lower than CFCs but still high by some accounts)
but the VOC content is low. Hydrocarbons have extremely low direct
global warming potential but they are considered VOCs.
[0005] Thus, there still remains an unfulfilled need to develop
reaction systems in which blowing agents have a zero ozone
depletion potential, and which produce foams with good balance of
properties for which rigid polyurethane foams are known.
SUMMARY OF THE INVENTION
[0006] Therefore, it is the object of the present invention to
provide closed celled rigid polyurethane or urethane-modified
polyisocyanurate foams which have, even when blown with
hydrofluorocarbons, equivalent or improved fire resistance
properties than CFC or HCFC blown foams.
[0007] It is another object of the present invention to provide
closed celled rigid polyurethane or urethane-modified
polyisocyanurate foams blown with hydrofluorocarbons which have
good thermal insulation and structural properties along with the
improved fire properties.
[0008] It has now been unexpectedly discovered that the use of over
40 weight % of aromatic polyester polyols of average functionality
lower than 3.0 as the polyfunctional isocyanate-reactive
composition, along with the use of organo-phosphorous compounds in
the foam formulation improves the fire properties of polyurethane
foam prepared in the presence of HFC blowing agents. Such HFC blown
foams also have surprisingly good thermal insulation and structural
properties along with the improved fire properties. The
compositions of the present invention advantageously make it
possible to obtain the balance of properties best suited to meet
both the commercial and environmental demands of the present
times.
[0009] It has now surprisingly been found that rigid polyurethane
foam having a density between 1.2 to 4.2 lb/cu.ft. with excellent
fire properties and good thermal and structural properties can be
obtained by using the formulation
[0010] (1) organic polyisocyanates,
[0011] (2) a blowing agent comprising
[0012] (a) C.sub.1-C.sub.4 hydrofluorocarbons which are vaporizable
under the foaming conditions as the physical blowing agent, and
[0013] (b) water
[0014] (3) polyfunctional isocyanate-reactive compositions
containing over 40 weight % of aromatic polyester polyols of
average functionality lower than 3.0,
[0015] (4) organo-phosphorous compounds, and
[0016] (5) one or more other auxiliaries or additives conventional
to formulations for the production of rigid polyurethane and
urethane-modified polyisocyanurate foams. Such optional additives
include, but are not limited to: crosslinking agents,
foam-stablilising agents or surfactants, catalyst, infra-red
opacifiers, cell-size reducing compounds, viscosity reducers,
compatibility agents, mold release agent, fillers, pigments, and
antioxidants, wherein the amount of said organo-phosphorous
compound used is such that the amount of phosphorous is between
about 0.01 to about 2.5% by weight, based on the total weight of
the foam forming reaction mixture.
[0017] In summary, the surprising technical advantages of this
invention are the discovery of rigid polyurethane foam formulations
blown using hydrofluorocarbons (zero ODP) blowing agents which give
foams whose fire performance in laboratory tests are equal or
superior to those foams blown with CFCs or HCFCs; structural
performance, such as compressive strength and long term dimensional
stability, is comparable or better than foam blown with CFCs or
HCFCs; and initial and long term insulation performance comparable
to those foams blown with CFCs or HCFCs.
[0018] The foams of the present invention are suitable for use in
continuous lamination boardstock foams for commercial roof and
residential wall insulation, as well as metal-faced panels, spray
foams, and fire-rated doors.
DETAILED DESCRIPTION OF THE INVENTION
[0019] Each of the above disclosed materials utilized in the foams
of the present invention are described hereinafter.
[0020] (1) Isocyanate:
[0021] Any organic polyisocyanates may be used in the practice of
the invention. A preferred isocyanate is polyphenylene
polymethylene polyisocyanate (PMDI). A most preferred isocyanate is
those PMDI with diphenyl methane diisocyanate content of about 15
to about 42% by weight based on 100% by weight of the
isocyanate.
[0022] The amount of isocyanate is typically about 30-75%, more
preferably about 40-70% and most preferably about 45-65% by weight
based on 100% of the total foam formulation.
[0023] (2a) HFC Blowing Agent:
[0024] Any of the C.sub.1-C.sub.4 hydrofluorocarbons which are
vaporizable under the foaming conditions can be used alone or as
mixtures. Suitable HFCs include difluoromethane (HFC-32);
trifluoromethane (HFC-23); 1,1-difluoroethane (HFC-152a);
1,1,1-trifluroethane (HFC-143a); 1,1,1,2-tetrafluoroethane
(HFC-134a); pentafluoroethane (HFC-125); all isomers of
pentafluoropropane (HFC-245 fa, ca, eb, ea etc.); all isomers of
heptafluoropropane (HFC-236 ca, cb, ea, eb); isomers of
pentaflurobutane (HFC-365); 1,1,1,4,4,4-hexafluorobutane
(HFC-356mffm). Preferred HFCs include 1,1,1,3,3-pentafluoropropane
(HFC-245fa); 1,1,1,3,3-pentaflurobutane (HFC-365mfc). Most
preferred is HFC-245fa.
[0025] Other blowing agents, especially air, nitrogen, carbon
dioxide, alkanes, alkenes, ethers may be used as the minor physical
blowing agent. Representative alkanes include n-butane, n-pentane,
isopentane, cyclopentane and mixtures thereof. Representative
alkenes include 1-pentene. Representative ethers include dimethyl
ether.
[0026] (2b) Water:
[0027] Water reacts with isocyanate under foam forming conditions
to liberate CO.sub.2. Water could be used with any of the physical
blowing agents specified in 2(a).
[0028] The blowing agents are employed in an amount sufficient to
give the resultant foam the desired density between 1.2 to 4.2
lb/cu.ft, preferably 1.4 to 4.0 lb/cu. ft., and most preferably 1.6
to 3.8 lb/cu. ft. Additionally, the amount of HFC used is such that
the gaseous mixture in the closed cell of the rigid foam when
initially prepared is between about 99-20%, preferably about
97-30%, most preferably about 95-40% molar percent HFC.
[0029] (3) Polyfunctional Isocyanate-reactive Compositions:
[0030] These typically contain over about 40 weight % of aromatic
polyester polyols of average functionality less than 3, the
remaining being other types of isocyanate-reactive compound.
[0031] Suitable aromatic polyester polyols include those prepared
by reaction a polycarboxylic acid and/or a derivative thereof or an
anhydride with a polyhydric alcohol, wherein at least one of these
reactants is aromatic. The polycarboxylic acids may be any of the
known aliphatic, cycloaliphatic, aromatic, and/or heterocyclic
polycarboxylic acids and may be substituted, (e.g., with halogen
atoms) and/or unsaturated. Examples of suitable polycarboxylic
acids and anhydrides include oxalic acid, malonic acid, glutaric
acid, pimelic acid, succinic acid, adipic acid, suberic acid,
azelaic acid, sebacic acid, phthalic acid, isophthalic acid,
terephthalic acid, trimellitic acid, trimellitic acid anhydride,
pyromellitic dianhydride, phthalic acid anhydride,
tetrahydrophthalic acid anhydride, hexahydrophthalic acid
anhydride, endomethylene tetrahydrophthalic acid anhydride,
glutaric acid anhydride acid, maleic acid, maleic acid anhydride,
fumaric acid, and dimeric and trimeric fatty acids, such as those
of oleic acid which may be in admixture with monomeric fatty acids.
Simple esters of polycarboxylic acids may also be used such as
terephthalic acid dimethylester, terephthalic acid bisglycol and
extracts thereof.
[0032] Examples of suitable aromatic polycarboxylic acids are:
phthalic acid, isophthalic acid, terephthalic acid, and trimellitic
acid. Suitable aromatic polycarboxylic acid derivatives are:
dimethyl or diethyl esters of polycarboxylic acids such as phthalic
acid, isophthalic acid, terephthalic acid, and trimellitic acid.
Examples of suitable aromatic anhydrides are phthalic anhydride,
tetrahydrophthalic anhydride, and pyromellitic anhydride.
[0033] While the polyester polyols can be prepared from
substantially pure reactant materials as listed above, more complex
ingredients may be advantageously used, such as the side-streams,
waste or scrap residues from the manufacture of phthalic acid,
phthalic anhydride, terephthalic acid, dimethyl terephthalate,
polyethylene terephthalate, and the like.
[0034] The polyhydric alcohols suitable for the preparation of
polyester polyols may be aliphatic, cycloaliphatic, aromatic,
and/or heterocyclic. The polyhydric alcohols optionally may include
substituents which are inert in the reaction, for example, chlorine
and bromine substituents, and/or may be unsaturated. Suitable amino
alcohols, such as monoethanolamine, diethanolamine or the like may
also be used. Examples of suitable polyhydric alcohols include
ethylene glycol, propylene glycol, polyoxyalkylene glycols (such as
diethylene glycol, polyethylene glycol, dipropylene glycol and
polypropylene glycol), glycerol and trimethylolpropane. Examples of
suitable aromatic polyhydric alcohols are 1,4, benzene diol,
hydroquinone di (2-hydroxyethyl) ether, bis (hydroxyethyl)
terephthalate, and resorcinol.
[0035] The polyester polyol utilized in the present invention is
aromatic and has an average functionality of less than 3. Thus,
either the polycarboxylic acid (and/or a derivative thereof or an
anhydride component) or the polyhydric alcohol or both are aromatic
and the average functionality of reaction product is less than 3.0.
There are a number of such polyols commercially available.
STEPANPOL.RTM. PS-2352, PS-2402, PS-3152 are some such polyols
manufactured by the Stepan Company. TERATE.RTM. 2541, 254, 403, 203
are some such polyols, manufactured by Hoechst-Celanese
Corporation,. TEROL.RTM. 235, 235N, 250 are some such polyols
manufactured by Oxid, Inc.
[0036] The polyfunctional isocyanate-reactive compositions may
contain up to 60% of other suitable isocyanate-reactive compounds.
Examples of such compositions include polyether polyols, aliphatic
polyester polyols and mixtures thereof, having equivalent weights
from about 40 to about 4000 of preferably about 50 to about 3000
and average hydroxyl functionalities of about 2 to about 8 and
preferably about 2 to about 6. Further examples of suitable
polyfunctional isocyanate-reactive compositions include active
hydrogen-terminated polythioethers, polyamides, polyester amides,
polycarbonates, polyacetals, polyolefins and polysiloxanes.
Additional useful isocyanate-reactive materials include primary and
secondary diamines (Unilink 4200), enamines, cyclic ureas, cyclic
carbonate, and polycarboxylic acid. Some of these compounds react
with isocyanate to evolve carbon dioxide and contribute to foam
blowing.
[0037] (4) Organo-phosphorous Compounds:
[0038] Various phosphorous-containing organic compounds can be
used. Suitable compounds include phosphates, phosphites,
phosphonates, polyphosphates, polyphosphites, polyphosphonates,
ammonium polyphosphate. Suitable phosphate compounds are of the
following formula: 1
[0039] where R.sup.1 to R.sup.3 signifies alkyl, halogen
substituted alkyl, aryl, halogen substituted aryl and cycloalkyl
groups. Preferred phosphates are those where R.sup.1 to R.sup.3
signifies C.sub.1-C.sub.12 alkyl, C.sub.1-C.sub.12 halogen
substituted alkyl, phenyl, cresyl, halogen substituted phenyl and
C.sub.5-C.sub.10 cycloalkyl groups. More preferred phosphates are
those where R.sup.1 to R.sup.3 signifies C.sub.1-C.sub.8 alkyl,
C.sub.1-C.sub.8 halogen substituted alkyl, and phenyl groups. Most
preferred phosphate compounds are those where R.sup.1 to R.sup.3
signifies C.sub.1-C.sub.4 alkyl, C.sub.1-C.sub.4 halogen
substituted alkyl, and phenyl groups. Some specific compounds under
most preferred phosphates are tributyl phosphate,
tris(2-chloropropyl)-phospha- te (Antiblaze 80 from Albright &
Wilson), t-butylphenyl diphenylphosphate (Phosflex 71B from Akzo
Nobel), triethyl phosphate (TEP from Eastman), tributyl phosphate
(Phosflex 4 from Akzo Nobel), chloropropyl bis(bromopropyl)
phosphate (Firemaster FM836 from Great Lakes).
[0040] Suitable phosphite compounds are of the following formula:
2
[0041] where R.sup.1 to R.sup.3 signifies H, alkyl, halogen
substituted alkyl, aryl, halogen substituted aryl and cycloalkyl
groups. Preferred phosphites are those where R.sup.1 to R.sup.3
signifies C.sub.1-C.sub.12 alkyl, C.sub.1-C.sub.12 halogen
substituted alkyl, phenyl, cresyl, halogen substituted phenyl and
C.sub.5-C.sub.10 cycloalkyl groups. More preferred phosphites are
those where R.sup.1 to R.sup.3 signifies, C.sub.1-C.sub.8 alkyl,
C.sub.1-C.sub.8 halogen substituted alkyl, and phenyl groups. Most
preferred phosphite compounds are those where R.sup.1 to R.sup.3
signifies C.sub.1-C.sub.4 alkyl, C.sub.1-C.sub.4 halogen
substituted alkyl, and phenyl groups. Some especially suitable
phosphates are triethyl phosphite (Albrite TEP from Albright &
Wilson), tris(2-chloroethyl)-phosphite, and triphenyl phosphite
(Albrite TPP).
[0042] Suitable phosphonate compounds are of the following formula:
3
[0043] where R.sup.1 to R.sup.3 signifies alkyl, halogen
substituted alkyl, aryl, halogen substituted aryl and cycloalkyl
groups. Preferred phosphonates are those where R.sup.1 to R.sup.3
signifies C.sub.1-C.sub.12 alkyl, C.sub.1-C,.sub.12 halogen
substituted alkyl, phenyl, cresyl, halogen substituted phenyl and
C.sub.5-C.sub.10 cycloalkyl groups. More preferred phosphonates are
those where R.sup.1 to R.sup.3 signifies C.sub.1-C.sub.8 alkyl,
C.sub.1-C.sub.8 halogen substituted alkyl, and phenyl groups. Most
preferred phosphonate compounds are those where R.sup.1 to R.sup.3
signifies C.sub.1-C.sub.4 alkyl, C.sub.1-C.sub.4 halogen
substituted alkyl, and phenyl groups. Some especially suitable
phosphonates are diethyl ethyl phosphonate (Amgard V490 from
Albright & Wilson), dimethyl methyl phosphanate (Amgard DMMP),
bis(2-chloroethyl), and 2-chloroethyl phosphonate.
[0044] Illustrative examples of polyphosphate compound are Amgaurd
V-6, a chlorinated diphosphate ester, from A&W. Illustrative
examples of ammonium polyphosphate [(NH4PO3).sub.n=about 1000) is
Hostaflam AP 422 from Hoechst AG.
[0045] The organo-phosphorous compounds used in the invention may
have one or more isocyanate-reactive hydrogen comprising of
hydroxyl group, amino group, thio group, or mixture thereof.
Suitable compounds include monomeric or oligomeric phosphates,
phosphites, and phosphonates polyols. Suitable isocyanate-reactive
phosphate compounds are those prepared by (1) the reaction of
polyalkylene oxides with (a) phosphoric acids (b) partial esters of
phosphoric acids; (2) the reaction of aliphatic alcohols with (a)
phosphoric acids (b) partial esters of phosphoric acids; and (3) by
transesterification of products of (l) and (2). The preferred
compounds include tributoxyethyl phosphate (Phosflex T-BEP from
Akzo); oligomeric organophosphate diol (Hostaflam TP OP 550 from
Hoechst AG); ethoxylated phosphate esters (Unithox X-5126 from
Petrolite); and mono- and diesters of phosphoric acid and alcohols
(Unithox X-1070 from Petrolite).
[0046] Suitable isocyanate-reactive phosphite compounds are those
prepared by (1) the reaction of polyalkylene oxides with (a)
phosphorous acids (b) partial esters of phosphorous acids; (2) the
reaction of aliphatic alcohols with (a) phosphorous acids (b)
partial esters of phosphorous acids; and (3) by transesterification
of products of (1) and (2).
[0047] Suitable isocyanate-reactive phosphonate compounds are those
prepared (1) by the reaction of polyalkylene oxides with phosphonic
acids, (2) by the reaction of phosphite polyols with alkyl halides;
(3) by the condensation of dialkyl phosphonates, diethanolamine and
formaldehyde; (4) by transesterification of products of (1) (2) and
(3); and (5) by reaction of dialkyl alkyl phosphonate with
phosphorous pentaoxide and alkylene oxide. The preferred compounds
include diethyl N,N-bis(2-hydroxyethyl) aminoethyl phosphonate
(Fyrol 6 from Akzo); hydroxyl containing oligomeric phosphonate
(Fyrol 51 from Akzo).
[0048] The amount of said organo-phosphorous compound used is such
that the amount of phosphorous is between about 0.01 to about 2.5%
by weight, based on the total weight of the foam forming reaction
mixture. Preferred amount of phosphorous is between about 0.025 to
about 1.5% and most preferred is about 0.05 to about 1.0% by
weight, based on the total weight of the foam forming reaction
mixture.
[0049] (5) Additives:
[0050] The resin side can also contain various auxiliary agents and
additives as needed for a particular purpose. Suitable auxiliaries
and additives include crosslinking agents, such as triethanolamine
and glycerol; foam stabilizing agents or surfactants, such as
siloxane-oxyalkylene copolymers; oxyethylene-oxyalkylene copolymer;
catalysts, such as tertiary amines, (e.g., dimethylcyclohexylamine,
pentamethyldiethylenetriamine, 2,4,6-tris(dimethylaminomethyl)
phenol, triethylenediamine); organometallic compounds (e.g.,
potassium octoate, potassium acetate, dibutyl tin dilaurate),
quaternary ammonium salts (e.g., 2-hydroxypropyl trimethylammonium
formate) and n-substituted triazines
(N,N',N"-dimethylaminopropylhexahydrotriazine); viscosity reducers
such as propylene carbonate, 1-methyl-2-pyrrolidinone; infra-red
opacifiers such as carbon black, titanium dioxide, metal flakes;
cell-size reducing compounds such as inert, insoluble fluorinated
compounds, perfluorinated compounds; reinforcing agent such as
glass fibers, ground up foam waste; mold release agents, such as
zinc stearate; antioxidents, such as butylated hydroxy toluene; and
pigments such as azo-/diazo dyestuff, phthalocyanines.
[0051] Amount of such additives are generally between about 0.
1-20%, preferably between about 0.3-15% and most preferably between
about 0.5-10%, by weight based on 100% of the total foam
formulation.
[0052] In carrying out the process for making rigid foams according
to this invention, the known one-shot, prepolymer or
semi-prepolymer techniques may be used together with conventional
mixing methods including impingement mixing. The rigid foam may be
produced in the form of slabstock, mouldings, cavity filling,
sprayed foam, frothed foam or laminates with other material such as
paper, metal, plastics, or wood-board.
[0053] The various aspects of this invention are illustrated, but
not limited by, the following examples. Unless otherwise noted, all
temperatures are expressed in degrees Celsius and all formulation
components are expressed in parts by weight.
EXAMPLES
[0054] Following materials are referred to in the examples.
[0055] STEPANPOL.RTM. PS-2352: An aromatic polyester polyol of
hydroxyl value 240 mg KOH/g, average functionality of around 2 and
viscosity of 3,000 cPs@25.degree. C. from Stepan company. The
aromatic polyester polyol content of this polyol is above 80% by
weight.
[0056] VORANOL.RTM. 240-800: A polyether polyol of hydroxyl value
800 mg KOH/g, average functionality of 3 and viscosity of 3,500
centiStokes@100.degree. F. from the Dow Chemical Company.
[0057] ALKAPOL.RTM. A-630: An aliphatic amine-based polyether
polyol of hydroxyl value 630 mg KOH/g, average functionality of 3
and viscosity of from 450 cPs@25.degree. C. the Dow Chemical
Company.
[0058] RUBINOL.RTM. RI 59: An aromatic amine-based polyether polyol
of hydroxyl value 500 mg KOH/g, average functionality of 3.2 and
viscosity of from 18000 cPs@25.degree. C. from ICI Americas
Inc.
[0059] RUBINOL.RTM. R124: An aromatic amine-based polyether polyol
of hydroxyl value 395 mg KOH/g, average functionality of 3.9 and
viscosity of from 18000 cPs@25.degree. C. from ICI Americas
Inc.
[0060] TCPP: Tri(beta-chloropropyl)phosphate (% P=9.5) available
from Akzo Nobel Chemical Inc.
[0061] TEP: Triethyl Phosphate (% P=17) available from Eastman
Chemical Corporation.
[0062] PELRON.RTM. 9540A: Potassium octoate in diethylene glycol
available from Pelron Corp.
[0063] PELRON.RTM. 9650: Potassium acetate in diethylene glycol
available from Pelron Corp.
[0064] POLYCAT.RTM. 5: Pentamethyldiethylenetriamine available from
Air Products.
[0065] DABCO.RTM. 33LV: Triethylenediamine in dipropylene glycol
available from Air Products.
[0066] DABCO.RTM. 125: An organotin polyurethane catalyst available
from Air Products.
[0067] TEGOSTAB.RTM. B84PI: A silicone surfactant available from
Goldschmidt Corporation.
[0068] TEGOSTAB.RTM. B8404: A silicone surfactant available from
Goldschmidt Corporation.
[0069] LK-221.RTM.: A non-silicone surfactant available from Air
Products.
[0070] HCFC-141b: Dichlorofluoroethane blowing agent available from
Elf-Atochem North America.
[0071] HFC-245fa (Pressurized): Available from AlliedSignal
Chemicals.
[0072] RUBINATE.RTM. 1850: A high functionality polymeric MDI
available from ICI Americas.
Example 1
[0073] A number of rigid polyurethane foams were prepared using the
formulations shown in Table 1. All foams were made using the
following general procedure.
[0074] Polyol blend was made by mixing together all the ingredients
listed under "Polyol Side" except the HFC-245fa using a high speed
mixer at room temperature. The polyol blend was added to the
"Polyol Side" tank of a Edge-Sweets high pressure impingement mix
dispense machine. An appropriate amount of HFC-245fa, based on the
composition shown in Table 2, was added to the "Polyol Side" tank
and mixed vigorously using an air-mixer attached to the tank.
Isocyanate was added to the "Iso side" tank attached to the
dispense machine. The machine parameters were set as follows:
1 Machine Parameters Foam #1, 2 & 3 Foam #4 "Iso Side"
temperature, .degree. F. 70 80 "Polyol Side" temperature, 60 70
.degree. F. Mix pressure, psig 2,000 2,000 "Iso Side" Pump RPM 70
70 "Polyol Side" Pump RPM Adjusted to give the Adjusted to give the
Polyol to Iso side Polyol to Iso side weight ratio shown weight
ratio shown in Table 1 in Table 1 Dispense rate, gms/second 200
200
[0075] The foaming ingredients were shot from the dispense machine
into a 5-liter cup and reactivity and density were measured on this
free-rise foam. The foam core density was measured following ASTM D
1622. Fire performance was tested on foam specimens taken from
4".times.15".times.15" foam blocks according to the Butler Chimney
Test, ASTM D 3014. This test measures the weight retention and
flame extinguishing time of foam specimen. Fire performance was
also measured by the Hot Plate Test on core specimens taken from
7".times.7".times.15" foams made by dispensing foaming ingredients
into a cardboard box. The Hot Plate test is described in
"Flammability Study of Hydrocarbon-Blown Isocyanurate Foams, "
Proceedings of the 35th Annual SPI Polyurethane Technical/Marketing
Conference, Page 561 (1994). The maximum smoke density under
flaming conditions in NBS Smoke Test was measured according to ASTM
E662.
[0076] The structural properties were measured on core specimens
taken from 7".times.7".times.15" foams made by dispensing foaming
ingredients into a cardboard box. The low temperature dimensional
stability was measured after 7 days of exposure at -25.degree. C.
following the "Dimvac method" described in "Techniques to Assess
the Various Factors Affecting the Long Term Dimensional Stability
of Rigid Polyurethane Foam," Proceedings of the Polyurethane 1995
Conference, Page 11 (1995). The compressive strength was measured
parallel and perpendicular to the foam rise direction, following
ASTM D 1621, Procedure A. Thermal properties of the foams were
measured according to the procedures set forth in ASTM C 518 on
core foam taken from 4".times.15".times.15" foam blocks. Foams #1
and #2 represent the foams prepared using the formulations
according to this invention. Foam #3 and #4 represent the
comparative foams. Foams #1, #2 and #3 were blown using a zero ODP
blowing agent HFC-245fa. The formulation used to make Foam #4
represents the present state of art and is blown using a ozone
depleting blowing agent HCFC-141b.
[0077] In Butler Chimney Test, a higher weight retention, lower
flame height and lower flame extinguish time indicate a superior
fire resistance. As we can see from Table 1, the fire resistance
performances (as measured by Butler Chimney test) of Foam #1 and
Foam #2 are much better than Foam #3, and equivalent to or better
than Foam #4. In the Hot Plate Test, a higher weight retention and
a higher thickness retention imply superior fire resistance. The
fire resistance properties (as measured by Hot Plate Test) of Foam
#1 and Foam #2 are much better than Foam #3 and equivalent to or
better than Foam #4. In the NBS smoke test, the lower the maximum
smoke density, the better the fire resistance of the foam. Once
again, Foam #1 and Foam #2 gave much better fire resistance results
than Foam #3 and Foam #4. Thus in all of the laboratory fire tests,
Foam #1 and Foam #2 gave a much better fire resistance performance
than Foam #3 and equivalent to or better than Foam #4. Though Foams
#1, #2 and #3 are blown using a HFC and use >50% aromatic
polyester polyol, only Foams #1 and #2 contain the
organo-phosphorous compound disclosed in this invention. Foam #4
which represents the present state of art, also does not use the
organo-phosphorous compound and is blown using a HCFC blowing
agent, HCFC-141b.
[0078] In a dimensional stability test, the closer the % linear
change is to zero, the better the dimensional performance of foam.
Foams # 1 and Foam #2 gave better dimensional stability as compared
to Foam #3 and Foam #4. In the compressive strength measurements,
the higher the number the better the structural performance of the
foam. Here too, Foams # I and Foam #2 gave better performance than
Foam #3 and Foam #4.
[0079] In thermal property evaluations, the lower the k-factor, the
better the insulation performance of the foam. In Table 1, we see
that the initial k-factor of Foams #1, #2 and #3 are the same,
though slightly higher than that for #4. The aged k-factor of the
inventive Foam #1 & #2 is lower and thus better than the
present state of art, Foam #4.
Example 2
[0080] For comparison, a rigid polyurethane foam #5, was prepared
using the formulation shown in Table 2. Foam #5 was made using an
organic polyisocyanate, a hydrofluorocarbon (HFC-245fa) as blowing
agent, polyether polyols as polyfunctional isocyanate-reactive
composition, an organo-phosphorous compound and other additives.
Foam #5 did not use an aromatic polyester polyol as polyfunctional
isocyanate-reactive composition and thus is a comparative foam.
[0081] As can be seen from Table 2, the fire resistance performance
(as measured by Butler Chimney test, Hot Plate Test and the NBS
smoke test) of Foam #5 was much worse than Foam #1 and #2. The fire
resistance properties of Foam #5 were similar to Foam #3 and poor.
Though Foams #1, #2 and #5 were blown using a HFC and contained the
organo-phosphorous compound, only Foams #1 and #2 used aromatic
polyester polyols as disclosed in this invention. This suggested
that both the organo-phosphorous compound and aromatic polyester
polyol were required to get the good fire resistance when using a
HFC blowing agent.
[0082] The structural properties of Foam #5 were similar to Foams #
1 and #4, and were acceptable. Both the initial and the aged
k-factor of Foam #5 were not as good as the inventive Foam #1 and
#2. The aged k-factor of Foam #5 was similar to the present state
of art, Foam #4.
[0083] The results clearly demonstrated that when blown with an
environmentally acceptable HFC blowing agent, the foams (#1 and #2)
made using the formulations of the invention gave superior fire
resistance performance and equivalent or superior structural and
thermal insulation performance, as compared with foams (#3 &
#5) made using formulations outside of this invention. The
formulations of the present invention made it possible to produce
foams whose flame retardancy, structural, and thermal insulation
performance were equivalent to or better than those made using
current HCFC blowing agent.
[0084] The present invention has been described in considerable
detail above. It will be understood that modifications routinely
made by one of ordinary skill in the art are to be considered
within the scope of the present invention.
2TABLE 1 Foam Foam Foam Foam Foam Samples #1 #2 #3 #4 "Polyol Side"
Stepanpol PS-2352 100 100 100 100 TCPP 7.5 TEP 7.5 Tegostab B84PI 2
Tegostab B8404 1.5 1.5 1.5 Pelron 9540A 2.2 2.2 2.2 1.75 Pelron
9650 0.7 0.7 0.7 0.6 Polycat 5 0.5 0.5 0.5 0.5 Water 0.5 0.5 0.5
0.5 HCFC-141b 31 HFC-245fa 40.2 40.2 39 "Iso Side" Rubinate 1850
177.6 177.6 177.6 180 % Phosphorous in foam 0.22 0.42 0 0
formulation Aromatic polyol as a weight % of 80+ 80+ 80+ 80+
isocyanate-reactive composition Reactivities: Cream Time, seconds 4
3 4 9 Gel Time, seconds 20 17 21 18 Tack-Free Time, seconds 25 21
30 23 Foam Properties: Free rise density, pcf 2.0 2.0 1.9 1.9 Fire
Performance Butler Chimney Test % Weight retained 90 97 36 94
Maximum flame height, cm 24 16 25+ 25+ Flame extinguish time,
seconds 18 11 37 11 Hot Plate Test % Weight retained 73 71 44 71 %
Thickness retained 97 90 12 91 Maximum Smoke Density 84 67 104 108
Structural Properties: Dimensional stability, -0.1 -0.1 -0.3 -0.3 %
linear change 7 days at -25.degree. C., Compressive Strength, psi
Parallel to rise 61 50 49 52 Perpendicular to rise 21 17 14 15
Thermal Properties: k-factor in BTU.in/ft.sup.2.hr..degree. F.
Initial 0.133 0.133 0.133 0.128 After 3 months at room 0.151 0.154
0.155 0.162 temperature
[0085]
3TABLE 2 Foam Samples Foam #5 "Polyol Side" Voranol 240-800 28.6
Alkapol A-630 19.0 Rubinol R159 44.1 Rubinol R124 8.3 TCPP 8.3
LK-221 1.4 Dabco 33LV 0.7 Dabco 125 0.7 HFC-245fa 26.7 "Iso Side"
Rubinate M 151.4 % Phosphorous in foam formulation 0.27 Aromatic
polyol as a weight % of isocyanate-reactive 0 composition Foam
Properties: Foam density, pcf 2.6 Fire Performance Butler Chimney
Test % Weight retained 14.4 Maximum flame height, cm 25+ Flame
extinguish time, seconds 42 Hot Plate Test % Weight retained 0 %
Thickness retained 0 Maximum Smoke Density 506 Structural
Properties: Dimensional stability, 7 days at -25.degree. C., %
linear -1 change Compressive Strength, Parallel to rise, psi 50
Compressive Strength, Perpendicular to rise, psi 29 Thermal
Properties: k-factor in BTU.in/ft.sup.2.hr..degree. F. Initial
0.142 After 3 months at room temperature 0.160
* * * * *