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Claims  |
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What is claimed is:
1. A premix comprising polyol, hydrohalocarbon blowing agent, and at least
one additive wherein said at least one additive is capable of decreasing
the amount of decomposition of said hydrohalocarbon blowing agent to
haloalkenes.
2. A composition comprising polyol, hydrohalocarbon blowing agent,
catalyst, surfactant, and at least one additive wherein said at least one
additive is capable of decreasing the amount of decomposition of said
hydrohalocarbon blowing agent to haloalkenes.
3. A composition comprising polyisocyanate, polyol, hydrohalocarbon blowing
agent, catalyst for polymerization of said polyisocyanate and said polyol,
surfactant, and at least one additive wherein said at least one additive
is capable of decreasing the amount of decomposition of said
hydrohalocarbon blowing agent to haloalkenes during polymerization of said
polyisocyanate and said polyol.
4. The composition of claim 3 wherein said hydrohalocarbon blowing agent is
selected from the group consisting of hydrofluorocarbon and
hydrochlorofluorocarbon.
5. The composition of claim 4 wherein said hydrohalocarbon blowing agent is
hydrofluorocarbon.
6. The composition of claim 5 wherein said hydrofluorocarbon blowing agent
is selected from the group consisting of 1,1-difluoroethane;
1,2-difluoroethane; 1,1,1-trifluoroethane; 1,1,2-trifluoroethane;
1,1,1,2-tetrafluoroethane; 1,1,2,2-tetrafluoroethane;
1,1,1,2,2-pentafluoroethane; 1,1,1,3-tetrafluoropropane;
1,1,2,3,3-pentafluoropropane; and 1,1,1,3,3-pentafluoro-n-butane.
7. The composition of claim 4 wherein said hydrohalocarbon blowing agent is
hydrochlorofluorocarbon.
8. The composition of claim 7 wherein said hydrochlorofluorocarbon blowing
agent is 1-chloro-1,2-difluoroethane; 1-chloro-2,2-difluoroethane;
1-chloro-1,1-difluoroethane; 1,1-dichloro-1-fluoroethane;
1-chloro-1,1,2-trifluoroethane; 1-chloro-2,2-trifluoroethane;
1,1-dichloro-1,2-difluoroethane; 1-chloro-1,1,2,2-tetrafluoroethane;
1-chloro-1,2,2,2-tetrafluoroethane; 1,1-dichloro-1,2,2-trifluoroethane;
1,1-dichloro-2,2,2-trifluoroethane; 1,2-dichloro-1,1,2-trifluoroethane;
mixtures of 1,1-dichloro-1-fluoroethane and
1,1-dichloro-2,2,2-trifluoroethane; and mixtures of
1,1-dichloro-2,2,2-trifluoroethane and 1,2-dichloro-1,2,2-trifluoroethane.
9. The composition of claim 3 wherein said haloalkenes include
1-chloro-1-fluoroethylene; 1,1-dichloroethylene; and
1,1-dichloro-2,2-difluoroethylene.
10. The composition of claim 3 wherein said at least one additive is
additive selected from the group consisting of esters, organic acids,
anhydrides, aminoacids, ammonium salts, bromoalkanes, bromoalcohols,
bromoaromatic esters, chloroalcohols, nitroalkanes, nitroalcohols,
triarylmethyl chlorides, triarylmethyl bromides, 3-sulfolene, zinc
dialkyldithiophosphate, sulfonate esters, haloalkyl phosphate esters,
carbon molecular sieves, activated carbon, and zeolite molecular sieves.
11. The composition of claim 10 wherein said at least one additive is
present in an amount up to about 10 parts by weight per hundred parts of
said polyol.
12. The composition of claim 3 wherein said at least one additive is
additive selected from the group consisting of esters, organic acids,
anhydrides, aminoacids, ammonium salts, bromoalkanes, bromoalcohols,
chloroalcohols, nitroalkanes, nitroalcohols, triarylmethyl chlorides,
triarylmethyl bromides, 3-sulfolene, zinc dialkyldithiophosphate,
haloalkyl phosphate esters, carbon molecular sieves, activated carbon,
zeolite molecular sieves, sulfonate esters, and chloroalkyl phosphates.
13. The composition of claim 3 wherein said at least one additive is
selected from the group consisting of bromoalkanes, bromoalcohols,
chloroalcohols, and nitroalkanes.
14. The composition of claim 10 wherein at least two additives are present.
15. The composition of claim 14 wherein said second additive is selected
from the group consisting of nitroalkanes, bromoalkanes, bromoalcohols,
chloroalcohols, and di(hydroxyalkyl)esters of tetrabromophthalic acid.
16. A process for preparing polyurethane or polyurethane modified
polyisocyanurate foams comprising the step of:
reacting polyol with polyisocyanate in the presence of hydrohalocarbon
blowing agent, catalyst, surfactant, and at least one additive wherein
said at least one additive is capable of decreasing the amount of
decomposition of said hydrohalocarbon blowing agent to haloalkenes during
polymerization of said polyisocyanate and said polyol.
17. Polyurethane or polyurethane modified polyisocyanurate foams prepared
by the process of claim 16.
18. Polyurethane or polyurethane modified polyisocyanurate foam articles
prepared by the process of claim 16.
19. The process of claim 16 wherein said hydrohalocarbon blowing agent is
selected from the group consisting of hydrofluorocarbon and
hydrochlorofluorocarbon.
20. The process of claim 19 wherein said hydrohalocarbon blowing agent is
hydrofluorocarbon.
21. The process of claim 20 wherein said hydrofluorocarbon blowing agent is
selected from the group consisting of 1,1-difluoroethane;
1,2-difluoroethane; 1,1,1-trifluoroethane; 1,1,2-trifluoroethane;
1,1,1,2-tetrafluoroethane; 1,1,2,2-tetrafluoroethane;
1,1,1,2,2-pentafluoroethane; 1,1,3-tetrafluoropropane;
1,1,2,3,3-pentafluoropropane; and 1,1,1,3,3-pentafluoro-n-butane.
22. The process of claim 19 wherein said hydrohalocarbon blowing agent is
hydrochlorofluorocarbon.
23. The process of claim 22 wherein said hydrochlorofluorocarbon blowing
agent is 1-chloro-1,2-difluoroethane; 1-chloro-2,2-difluoroethane;
1-chloro-1,1-difluoroethane; 1,1-dichloro-1-fluoroethane;
1-chloro-1,1,2-trifluoroethane; 1-chloro-1,2,2-trifluoroethane;
1,1-dichloro-1,2-difluoroethane; 1-chloro-1,1,2,2-tetrafluoroethane;
1-chloro-1,2,2,2-tetrafluoroethane; 1,1-dichloro-1,2,2-trifluoroethane;
1,1-dichloro-2,2,2-trifluoroethane; 1,2-dichloro-1,1,2-trifluoroethane;
mixtures of 1,1-dichloro-1-fluoroethane and
1,1-dichloro-2,2,2-trifluoroethane; and mixtures of
1,1-dichloro-2,2,2-trifluoroethane and 1,2-dichloro-1,2,2-trifluroethane.
24. The process of claim 16 wherein said haloalkenes include
1-chloro-1-fluoroethylene; 1,1-dichloroethylene; and
1,1-dichloro-2,2-difluoroethylene.
25. The process of claim 16 wherein said at least one additive is additive
selected from the group consisting of esters, organic acids, anhydrides,
aminoacids, ammonium salts, bromoalkanes, bromoalcohols, bromoaromatic
esters, chloroalcohols, nitroalkanes, nitroalcohols, triarylmethyl
chlorides, triarylmethyl bromides, 3-sulfolene, zinc
dialkyldithiophosphate, sulfonate esters, haloalkyl phosphate esters,
carbon molecular sieves, activated carbon, and zeolite molecular sieves.
26. The process of claim 16 wherein said at least one additive is present
in an amount up to about 10 parts by weight per hundred parts of said
polyol.
27. The process of claim 16 wherein said at least one additive is additive
selected from the group consisting of esters, organic acids, anhydrides,
aminoacids, ammonium salts, bromoalkanes, bromoalcohols, chloroalcohols,
nitroalkanes, nitroalcohols, triarylmethyl chlorides, triarylmethyl
bromides, 3-sulfolene, zinc dialkyldithiophosphate, haloalkyl phosphate
esters, carbon molecular sieves, activated carbon, zeolite molecular
sieves, sulfonate esters, and chloroalkyl phosphates.
28. The process of claim 16 wherein said at least one additive is additive
selected from the group consisting of bromoalkanes, bromoalcohols,
chloroalcohols, and nitroalkanes.
29. The process of claim 16 wherein at least two additives are present.
30. The process of claim 29 wherein said second additive is selected from
the group consisting of nitroalkanes; bromoalkanes; bromoalcohols;
chloroalcohols; and di(hydroxyalkyl)esters of tetrabromophthalic acid.
31. The composition of claim 1 wherein said hydrohalocarbon blowing agent
is 1,1-dichloro-1-fluoroethane.
32. The composition of claim 1 wherein said additive is nitromethane.
33. The composition of claim 1 wherein said additive is
2,2,2-trichloroethanol.
34. The composition of claim 1 wherein said hydrohalocarbon blowing agent
is 1,1-dichloro-1-fluoroethane and said additive is nitromethane.
35. The composition of claim 1 wherein said hydrohalocarbon blowing agent
is 1,1-dichloro-1-fluoroethane and said additive is
2,2,2-trichloroethanol.
36. The composition of claim 2 wherein said hydrohalocarbon blowing agent
is 1,1-dichloro-1-fluoroethane.
37. The composition of claim 2 wherein said additive is nitromethane.
38. The composition of claim 2 wherein said additive is
2,2,2-trichloroethanol.
39. The composition of claim 2 wherein said hydrohalocarbon blowing agent
is 1,1-dichloro-1-fluoroethane and said additive is nitromethane.
40. The composition of claim 2 wherein said hydrohalocarbon blowing agent
is 1,1-dichloro-1-fluoroethane and said additive is
2,2,2,-trichloroethanol.
41. The composition of claim 3 wherein said hydrohalocarbon blowing agent
is 1,1-dichloro-1-fluoroethane.
42. The composition of claim 3 wherein said additive is nitromethane.
43. The composition of claim 3 wherein said additive is
2,2,2-trichloroethanol.
44. The composition of claim 3 wherein said hydrohalocarbon blowing agent
is 1,1-dichloro-1-fluoroethane and said additive is nitromethane.
45. The composition of claim 3 wherein said hydrohalocarbon blowing agent
is 1,1-dichloro-1-fluoroethane and said additive is
2,2,2-trichloroethanol. |
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Claims |
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Description |
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The present invention relates to polyurethane and polyisocyanurate foam
formulations in which the hydrohalocarbon blowing agent is stabilized
during polymerization by the presence of additives.
BACKGROUND OF THE INVENTION
It is well known to those skilled in the art that low density rigid
polyurethane and polyisocyanurate foams can be prepared by reacting and
foaming a mixture of ingredients including an organic polyisocyanate
(including diisocyanates) and an appropriate amount of polyol or mixture
of polyols in the presence of a volatile liquid blowing agent, which is
caused to vaporize by the heat liberated during the reaction of
polyisocyanate and polyol. It is also well known that this reaction and
foaming process require the use of amine and/or metal carboxylate
catalysts as well as surfactants. The catalysts ensure adequate curing of
the foam while the surfactants regulate and control cell size. The terms
polyisocyanurate foams and polyurethane modified polyisocyanurate foams
describe the same general class of rigid foams and are used
interchangeably in the industry.
In the class of foams known as low density rigid polyurethane or
polyisocyanurate foams, the blowing agent of choice has been
trichlorofluoromethane (known in the art as CFC-11). These types of foams
are closed-cell foams in which the CFC-11 vapor is encapsulated or trapped
in the matrix of closed cells. They offer excellent thermal insulation due
in part to the very low thermal conductivity of CFC-11 vapor and are used
widely in insulation applications such as roofing systems, building
panels, refrigerators, and freezers. Generally, about 1 to 60 parts by
weight, and more specifically, about 15 to 40 parts by weight of blowing
agent per 100 parts by weight polyol are used in rigid polyurethane or
polyisocyanurate formulations.
Chlorofluorocarbons (known as CFCs) including CFC-11 are now suspected
ozone depleting compounds which also contribute to the greenhouse warming
effect in the atmosphere. Other chlorofluorocarbons suspected of
possessing similar detrimental effects on the earth's atmosphere include
dichlorodifluoromethane (known in the art as CFC-12) and
1,1,2-trichloro-1,2,2-trifluoroethane (known in the art as CFC-113). Based
on the MONTREAL PROTOCOL ON SUBSTANCES THAT DEPLETE THE OZONE LAYER and
the CLEAN AIR ACT, alternatives to CFC solvents, propellants,
refrigerants, and blowing agents are being developed and commercialized
rapidly.
Hydrochlorofluorocarbons (known as HCFCs) are viewed as acceptable
alternatives to CFCs because they are inherently less chemically stable in
the earth's atmosphere, and have lower ozone depletion potentials and
greenhouse warming potentials than fully halogenated CFCs.
Certain hydrochlorofluorocarbons are known to be viable commercial
alternatives to the chlorofluorocarbon blowing agent, CFC-11, currently
being employed in the production of rigid polyurethane replacements for
CFC-11 are 11-dichloro-1-fluoroethane (known in the art as HCFC-141b) and
1,1-dichloro-2,2,2 -trifluoroethane (known in the art as HCFC-123) because
they both possess key physical properties similar to CFC-11 including
boiling point and thermal conductivity.
To ensure successful commercialization of these alternatives, it is
necessary that they be chemically stable under required processing
conditions and end uses. In particular, HCFCs are well known to undergo
degradation by dehydrohalogenation reactions to form halogenated alkenes.
Examples of such reactions are as follows:
##STR1##
Many of these haloalkene products possess unknown properties and it is
therefore desirable to hold their formation to a minimum as a
precautionary measure.
Tests performed using the above hydrohalocarbons as blowing agents, in
typical foam formulations now in commercial use, revealed that the
haloalkenes can be found in the cells of the cured foam at concentrations
up to about 10,000 parts/weight per million relative to the blowing agent.
Stabilizers have been added to hydrohalocarbons to inhibit or minimize the
generation and buildup of degradation products. For example, U.S. Pat. No.
4,861,926 teaches that 1,1,1-trichloroethane can be stabilized with
mixtures of epoxybutane, nitromethanes, 2-methylfuran, and methyl acetate
in textile dry cleaning and metal degreasing applications. Kokai Patent
Publication 103,843 published May 22, 1986 teaches that the addition of
benzotriazole stabilizes 1,2-dichloro-1-fluoroethane when it is exposed to
metallic surfaces in the presence of hydroxylic solvents, e.g. water or
alcohols. The abstract of Japanese 2,204,424 published Aug. 14, 1990
teaches that hydrochlorofluoropropanes in the presence of steel are
thermally stabilized by adding nitro compounds, phenols, amines, ethers,
esters, epoxides, alcohols, ketones, or triazoles.
Specialized chemical additives are often present in low density rigid
polyurethane and polyisocyanurate foams to enhance certain performance
features of the foam e.g. flame retardants, antioxidants, and solubilizing
surfactants. Such additives are dissolved in a formulation component or
pre-mix prior to foam production. Flame retardants include halocarbons,
e.g. chloroalkyl phosphate esters, polybromoalkanes, or
polybromoaromatics. Antioxidants are typically phosphite esters.
Solubilizing agents commonly used are ethoxylated nonylphenols.
We considered the use of additives to lower the concentration of volatile
haloalkene degradation products generated in rigid polyurethane and
polyurethane modified polyisocyanurate foam formulations blown with
saturated hydrohalocarbons.
SUMMARY OF THE INVENTION
We have found that certain additives are capable of decreasing the amount
of decomposition of the hydrohalocarbon blowing agent during
polymerization of the polyisocyanates and the polyols. Thus, the present
invention provides compositions comprising polyisocyanate, polyol,
hydrohalocarbon blowing agent, catalyst for the polymerization of the
polyisocyanate and the polyol, surfactant, and at least one additive
wherein the at least one additive is capable of decreasing the amount of
decomposition of the hydrohalocarbon blowing agent during polymerization
of the polyisocyanate and the polyol.
The term "haloalkenes" as used herein means those organic materials having
at least one double bond and at least one halogen atom therein. The
haloalkenes which form depend on the hydrohalocarbon blowing agent used.
For example, if the blowing agent is 1,1-dichloro-1-fluoroethane, the
haloalkenes which may form include 1,1-dichloroethylene and
1-chloro-1-fluoroethylene. If the blowing agent is
1,1-dichloro-2,2,2-trifluoroethane, the haloalkene which may form is
1,1-dichloro-2,2-difluoroethylene.
Preferably, the use of selected additive is effective when the amount of
haloalkenes formed by practice of the present invention is less than about
75% of the amount of haloalkenes formed in the absence of the present
invention. Thus, if the amount of haloalkenes formed in the absence of the
present invention is X, the amount of haloalkenes formed by the practice
of the present invention is less than about (0.75)(X). More preferably,
the amount of haloalkenes formed by practice of the present invention is
less than about 50% of the amount of haloalkenes formed in the absence of
the present invention. Thus, if the amount of haloalkenes formed in the
absence of the present invention is X, the amount of haloalkenes formed by
practice of the present invention is less than about (0.50)(X).
Other advantages of the present invention will become apparent from the
following description.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
During the production of typical commercial rigid polyurethane and
polyisocyanurate foams blown with 1,1-dichloro-1-fluoroethane, undesirable
concentrations of 1-chloro-1-fluoroethylene may be generated by a
dehydrochlorination side reaction. Unknown properties are associated with
HCFC-1131a and other haloalkenes that may be co-generated in any HCFC
blown polyurethane or polyisocyanurate foam wherein the blowing agent has
at least two carbon atoms. Thus, the concentration of these halogenated
alkenes must be reduced to the lowest possible levels during foam
production.
The procedure of the present invention efficiently leads to reduced levels
of haloalkenes, in particular, HCFC-1131a, in polyurethane and
polyisocyanurate foam blown with HCFC-141b. The present invention involves
adding a specific chemical compound to the given foam formulation.
Although not wishing to be bound by theory, we believe that the
dehydrohalogenation reactions are base initiated elimination reactions.
The additives presumably interfere with the reactive dehydrohalogenating
species so as to suppress haloalkene generation. Any chemical additive
which interferes with the reactive dehydrohalogenating species so as to
suppress haloalkene generation is useful in practicing the present
invention.
The preferred types of chemical additives that result in a substantial
reduction in the formation of haloalkenes during HCFC-141b blown foam
production are: esters, organic acids, anhydrides, aminoacids, ammonium
salts, bromoalkanes, bromoalcohols, bromoaromatic esters, chloroalcohols,
nitroalkanes, nitroalcohols, triarylmethyl chlorides, triarylmethyl
bromides, 3-sulfolene, zinc dialkyldithiophosphate (ZDTP), haloalkyl
phosphate esters, carbon molecular sieves, powdered activated carbon,
zeolite molecular sieves, sulfonate esters, and haloalkyl phosphate
esters. It is believed that hydroxyl, carboxyl, and unsubstituted amino
functionality in any of the additives ultimately react with polyisocyanate
thus incorporating the additive within the polymer framework.
Preferred esters include trihaloethyl esters of the formula RCO.sub.2
--CH.sub.2 --CX.sub.3 where R is selected from the group consisting of
hydrogen, alkyl having 1 to 18 carbon atoms, cycloalkyl, substituted
alkyl, aryl, and substituted aryl and X is Cl or Br. Examples include
2,2,2-trichloroethyl formate; 2,2,2-trichloroethyl benzoate;
2,2,2-trichloroethyl 3-hydroxypropanoate; 2,2,2-tribromoethyl acetate;
2,2,2-tribromoethyl 2-ethylhexanoate; and 2,2,2-tribromoethyl
4-methylbenzoate. Other preferred esters are of the formula CX.sub.3
--CO.sub.2 R' where R' is selected from the group consisting of alkyl
having 1 to 18 carbon atoms, cycloalkyl, substituted alkyl, aryl, and
substituted aryl and X is Cl or Br. Examples include phenyl
trichloroacetate; methyl trichloroacetate; 2-propyl tribromoacetate; and
benzyl tribromoacetate.
Preferred organic acids are either of the formula R.sup.1 R.sup.2 R.sup.3
C--CO.sub.2 H where R.sup.1, R.sup.2 , and R.sup.3 are the same or
different and selected from hydrogen, linear or branched alkyl,
hydroxyalkyl, cycloalkyl with alkyl groups containing 1 to 18 carbon
atoms, hydroxyl, halogen, dihydroxyalkyl, substituted alkyl, aryl,
hydroxyaryl, dihydroxyaryl, or R.sup.4 CO.sub.2 H where R.sup.4 is aryl,
alkylaryl, hydroxyaryl, and dihydroxyaryl. Examples include ethanoic acid;
formic acid; propanoic acid; butanoic acid; hexanoic acid; 2-ethylhexanoic
acid; lauric acid; cyclohexylacetic acid; hydroxyacetic acid; mono-, di-,
and tri-chloroacetic acid; mono-, di-, and tribromoacetic acid;
3-hydroxypropanoic acid; 2,3-dihydroxypropanoic acid; phenyl acetic acid;
diphenylacetic acid; 4-hydroxyphenyl acetic acid; 3,4-dihydroxyphenyacetic
acid; 4-methylphenylacetic acid; benzoic acid; 4-hydroxybenzoic acid;
3,4-dihydroxybenzoic acid; 4-methoxy benzoic acid; 4-nitrobenzoic acid;
12-nitrododecanoic acid; and p-toluic acid. The foregoing organic acids
are commercially available.
Preferred anhydrides are of the formula R.sup.1 (CO)O(CO)R.sup.2 wherein
R.sup.1 and R.sup.2 are the same or different and consist of straight
chain or branched alkyl radicals having 1 to 18 carbon atoms, cyclic
radicals having 1 to 18 carbon atoms, aryl radicals having 1 to 18 carbon
atoms, arylalkyl radicals having 1 to 18 carbon atoms, or R.sup.1 and
R.sup.2 form a covalent bond with each other. Examples include acetic
anhydride; cis-aconitic anhydride; bromomaleic anhydride; butyric
anhydride; chloroacetic anhydride; chlorodifluoroacetic anhydride;
crotonic anhydride; decanoic anhydride; dichloroacetic anhydride; glutaric
anhydride; heptanoic anhydride; hexanoic anhydride; homophthalic
anhydride; iodoacetic anhydride; itaconic anhydride; linoleic anhydride;
maleic anhydride; 3-methylglutaric anhydride; methylsuccinic anhydride;
oleic anhydride; palmitic anhydride; pentafluoropropionic anhydride;
2-phenylglutaric anhydride; propionic anhydride; stearic anhydride;
succinic anhydride; trichloroacetic anhydride; trifluoroacetic anhydride;
trimethylacetic anhydride; valeric anhydride; 4-bromo-,1,8-naphthalic
anhydride; benzoic anhydride; 4-chloro-1,8-napthalic anhydride; isatoic
anhydride; and tetrabromophthalic anhydride.
Other preferred anhydrides include dichloromaleic anhydride;
2,2-dimethylglutaric anhydride; 2,3-dimethylmaleic anhydride;
2,2-dimethylsuccinic anhydride; 2,3-diphenylmaleic anhydride; docosanoic
anhydride; 2-dodecen-1-ylsuccinic anhydride; 2-ethylhexanoic anhydride;
3-ethyl-3-methylglutaric anhydride; 3-hydroxyphthalic anhydride;
4-methylphthalic anhydride; 1,4,5,8-naphthalenetetracarboxylic anhydride;
1,8-naphthalic anhydride; 3,4-nitro-1,8-naphthalic anhydride; 3- and
4-nitrophthalic anhydride; phthalic anhydride; tetrabromophthalic
anhydride; tetrachlorophthalic anhydride;
endo-bicyclo[2.2.2]oct-5-ene-2,3-dicarboxylic anhydride;
bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride;
cis-1,2-cyclohexanedicarboxylic anhydride; 1-cyclopentene-1,2-dicarboxylic
anhydride; (.+-.)-hexahydro-4-methylphthalic anhydride;
cis-5-norbornene-endo-2,3-dicarboxylic anhydride;
cis-1,2,3,6-tetrahydrophthalic anhydride; 3,4,5,6-tetrahydrophthalic
anhydride; and diglycolic anhydride. The foregoing anhydrides are
commercially available.
Preferred aminoacids are of the formula R.sup.1 R.sup.2 NC(R.sup.3
R.sup.4)--CO.sub.2 H where R.sup.1, R.sup.2, R.sup.3 , and R.sup.4 are the
same or different and are selected from hydrogen, alkyl having 1 to 18
carbon atoms, cycloalkyl, substituted alkyl, aryl, substituted aryl, and
the corresponding alkali metal and alkaline earth carboxylate salts.
Examples include ethylenediaminetetraacetic acid (EDTA); EDTA disodium
salt; EDTA dipotassium salt; EDTA trisodium salt; EDTA tripotassium salt;
glycine; alanine; valine; leucine; isoleucine; phenylalanine; serine;
threonine; methionine; cysteine; cystine; tyrosine;
3,5-diiodo-D-thyronine; tryptophan; proline; hydroxyproline; aspartic
acid; and glutamic acid. The foregoing aminoacids are commercially
available.
Preferred ammonium salts are of the formula R.sup.1 R.sup.2 R.sup.3 N.sup.+
--H R.sup.4 R.sup.5 R.sup.6 C--CO.sub.2.sup.- where R.sup.1, R.sup.2,
R.sup.3, R.sup.4, R.sup.5, and R.sup.6 are the same or different and
selected from the group consisting of hydrogen, alkyl having 1 to 18
carbon atoms, cycloalkyl, substituted alkyl, aryl, and substituted aryl.
Examples include ammonium formate; ammonium acetate; ammonium
citrate(dibasic); ammonium oxalate; and ammonium L-tartrate(dibasic). Many
ammonium salts are commercially available.
Preferred bromoalkanes are of the formulas (Br).sub.a C(H).sub.b where a is
1, 2, 3, or 4 and a+b=4; (Br).sub.c (H).sub.d C--CH(R').sub.e
(R.sup.2).sub.f where c is 1, 2, or 3, c+d=3, e+f=2, and R' and R.sup.2
are the same or different and selected from the group consisting of
hydrogen, alkyl having 1 to 18 carbon atoms, substituted alkyl, haloalkyl,
aryl, and substituted aryl; and (Br).sub.g C(R.sup.3).sub.h
(R.sup.4).sub.i (R.sup.5).sub.j where g is 1, 2, 3, or 4 and g+h+i+j=4
R.sup.3, R.sup.4, and R.sup.5 are the same or different and selected from
the group consisting of hydrogen, linear alkyl having 1 to 18 carbon
atoms, substituted alkyl, haloalkyl, aryl, and substituted aryl. Examples
include bromomethane; dibromomethane; carbon tetrabromide; bromoform;
1,2-dibromobutane; 1,3-dibromobutane; 1,4-dibromobutane;
2,3-dibromobutane; 1,4-dibromo-2,3-butanediol; 2,3-dibromo-1,4-butanediol;
1,4-dibromo-2-butanol; 1,4-dibromo-2-butene; 1,10-dibromodecane;
1,2-dibromoethane; 1,12-dibromododecane; (1,2-dibromoethyl)benzene;
1,7-dibromoheptane; and 1,6-dibromohexane. The foregoing bromoalkanes are
commercially available.
Preferred bromoalcohols are of the formula (Br).sub.a (H).sub.b
(R.sup.1).sub.c C--C(H).sub.d (R.sup.2).sub.e OH where a is 1, 2, or 3; c
is 0 or 1; a+b+c=3; d is 1 or 2; d+e=2; and R.sup.1 and R.sup.2 are the
same or different and selected from the group consisting of hydrogen,
alkyl having 1 to 18 carbon atoms, cycloalkyl, substituted alkyl,
hydroxyalkyl, and aryl and when a=3 and d=e=1, R.sup.2 may also be OH or
OR.sup.2 wherein R.sup.2 is alkyl having 1 to 18 carbon atoms, cycloalkyl,
substituted alkyl, and hydroxyalkyl. Examples include
2,2,2-tribromoethanol; 2,2-dibromoethanol; 2-bromoethanol;
1,4-dibromo-2,3-butanediol; 2,3-dibromo-1,4-butanediol;
1,4-dibromo-2-butanol; 1,3-dibromo-propanol; 2,3-dibromopropanol;
2,2,2-tribromo-1,1-dihydroxyethane; and 2,2,2-tribromo-1-methoxyethanol.
Many of the foregoing bromoalcohols are commercially available.
Preferred bromoaromatic esters are of the formula C.sub.6 (Br).sub.4
(CO.sub.2 --R.sup.1)(CO.sub.2 --R.sup.2) where R.sup.1 is alkyl having 1
to 18 carbon atoms, substituted alkyl, hydroxyalkyl, aryl, and substituted
aryl and R.sup.2 is hydrogen and hydroxyalkyl. Examples include mono ethyl
ester of tetrabromophthalic acid; mono 2-hydroxyethyl ester of
tetrabromophthalic acid; (2-hydroxyprop-1-yl), (2'-hydroxyethoxy)ethyl,
mixed diester of tetrabromophthalic acid which is commercially available
as PHT4-DIOL.RTM. from Great Lakes Chemical Corporation.
Preferred chloroalcohols are of the formula (Cl).sub.a (H).sub.b
(R.sup.1).sub.c C--C(H).sub.d (R.sup.2).sub.e OH where a is 1, 2, or 3; c
is 0 or 1; a+b+c=3; d is 1 or 2; d+e=2; and R.sup.1 and R.sup.2 are the
same or different and selected from the group consisting of hydrogen,
alkyl having 1 to 18 carbon atoms, cycloalkyl, substituted alkyl,
hydroxyalkyl, and aryl and when a=3 and d=e=1, R.sup.2 may also be OH or
OR.sup.2 wherein R.sup.2 is alkyl having 1 to 18 carbon atoms, cycloalkyl,
substituted alkyl, and hydroxyalkyl. Examples include
2,2,2-trichloroethanol; 2,2-dichloroethanol; 2-chloroethanol;
1,3-dichloro-2-propanol; 1,4-dichloroethanol; 2,3-butanediol;
1,4-dichloro-2-butanol; 2,2-dichloro-1-pentanol; 1,1-dichloro-2-pentanol;
1-chloropentanol; 2-chloro-1-pentanol; 2-chloro-1-phenylethanol;
1-chloro-1-phenyl-2-propanol; 2,2,2-trichloro-1,1-dihydroxyethane; and
2,2,2-trichloro-1-methoxyethanol. Some chloroalcohols are commercially
available.
Preferred nitroalkanes are of the formula R.sup.1 R.sup.2 CH.sub.2 NO.sub.2
where R.sup.1 is selected from the group consisting of hydrogen, alkyl
having 1 to 18 carbon atoms, cycloalkyl, substituted alkyl, aryl, and
substituted aryl and R.sup.2 is selected from the group consisting of
hydrogen and methyl; and R.sub.3 --NO.sub.2 where R.sup.3 is aryl or
substituted aryl. Examples include nitromethane; nitroethane;
1-nitropropane; 2-nitropropane; 1-nitrobutane; nitrocyclohexane;
1-nitrohexane; nitrocyclopentane; 1-nitropentane; nitrobenzene; and
1-bromo-4-nitrobenzene. The foregoing nitroalkanes are commercially
available.
Preferred nitroalcohols are of the formula (R)CHOH--CH.sub.2 NO.sub.2 where
R is selected from the group consisting of hydrogen, alkyl having 1 to 18
carbon atoms, cycloalkyl, substituted alkyl, aryl, and substituted aryl.
Examples include commercially available 2-nitroethanol;
1-nitro-2-propanol; 2-nitro-1-propanol; and 1-phenyl-2-nitroethanol.
Preferred triarylmethyl chlorides are of the formula R.sub.3 CCl where R is
aryl or substituted aryl. Examples include commercially available
triphenylmethyl chloride; tri-(p-methoxyphenyl)methyl chloride; and
tri-(p-nonylphenyl)methyl chloride.
Preferred triarylmethyl bromides are of the formula R.sub.3 CBr where R is
aryl or substituted aryl. Examples include commercially available
triphenylmethyl bromide; tri-(p-methoxyphenyl)methyl bromide; and
tri(p-nonylphenyl)methyl bromide.
Preferred sulfonate esters are of the formula R.sup.1 SO.sub.2 OR.sup.2
where R.sup.1 is selected from the group consisting of aryl and
substituted aryl and R.sup.2 is selected from the group consisting of
alkyl having 1 to 18 carbon atoms and substituted alkyl. Examples include
commercially available methyl p-toluenesulphonate; ethyl benzenesulfonate;
and methyl p-bromobenzenesulfonate.
Preferred haloalkyl phosphate esters are of the formula [(X).sub.a
(H).sub.b (R.sup.1).sub.c C--CH(R.sup.2)O].sub.3 PO where X is chloro or
bromo, and a is 1, 2, or 3; c is 0 or 1; a+b+c=3; and R.sup.1 and R.sup.2
are selected from the group consisting of hydrogen, alkyl having 1 to 18
carbon atoms, cycloalkyl, substituted alkyl, aryl, and substituted aryl.
Examples include tri(2-chloroethyl) phosphate which is commercially
available as FYROL.RTM. CEF from Akzo Chemicals, Inc;
tri(1-chloro-2-propyl) phosphate which is commercially available as
FYROL.RTM. PCF from Akzo Chemicals, Inc; tri(2,2-dichloroethyl) phosphate;
tri(2,2,2-trichloroethyl) phosphate; tri(2-bromoethyl) phosphate;
tri(2,2-dibromoethyl) phosphate; and tri(2,2,2-tribromoethyl) phosphate.
Carbon molecular sieves such as those disclosed in commonly assigned U.S.
Pat. Nos. 4,906,796; 4,940,824; and 4,940,825 may be used in practicing
the present invention. Activated carbon such as that disclosed by commonly
assigned U.S. Pat. No. 4,950,816 may be used in practicing the present
invention. Zeolite molecular sieves such as those disclosed in commonly
assigned the present invention.
The more preferred additives include esters, organic acids, anhydrides,
aminoacids, ammonium salts, bromoalkanes, bromoalcohols, chloroalcohols,
nitroalkanes, nitroalcohols, triarylmethyl chlorides, triarylmethyl
bromides, 3-sulfolene, zinc dialkyldithiophosphate (ZDTP), haloalkyl
phosphate esters, carbon molecular sieves, powdered activated carbon,
zeolite molecular sieves, sulfonate esters, and haloalkyl phosphate
esters.
The most preferred additives include bromoalkanes, bromoalcohols,
chloroalcohols, and nitroalkanes.
Preferably, the additive is present at an amount of up to about 10 parts by
weight per hundred parts of polyol. More preferably, the additive is
present at an amount of about 0.2 part to about 10 parts by weight per
hundred parts of polyol. The additive is introduced preferably by
dissolution in the blowing agent, in the polyol, in a mixture of two or
more of the components, in the entire formulation mixture prior to
reaction with the polyisocyanate, or it can be added as a separate stream
at the point of mixing in the polymerization process. As such, the present
invention also provides a composition of hydrohalocarbon blowing agent and
at least one additive wherein the at least one additive is capable of
decreasing the amount of decomposition of the hydrohalocarbon blowing
agent to haloalkenes. The present invention also provides a premix of
polyol, hydrohalocarbon blowing agent, and at least one additive wherein
the at least one additive is capable of decreasing the amount of
decomposition of the hydrohalocarbon blowing agent to haloalkenes. The
present invention also provides a composition of polyol, hydrohalocarbon
blowing agent, catalyst, surfactant, and at least one additive wherein the
at least one additive is capable of decreasing the amount of decomposition
of the hydrohalocarbon blowing agent to haloalkenes. The additive is
introduced preferably by dissolution in the blowing agent or in the entire
formulation mixture prior to reaction with the polyisocyanate.
The beneficial effect of these selected chemical additives in polyurethane
and polyurethane modified polyisocyanurate foam formulations is realized
during the polymerization reaction within the normal processing time and
temperature conditions occurring during typical foam blowing.
Examples of polyols used in polyurethane foams include aromatic amino-based
polyether polyols such as those based on mixtures of 2,4-and
2,6-toluenediamine condensed with ethylene oxide and/or propylene oxide.
These polyols are used in pour-in-place molded foams. Another example is
aromatic alkylamino-based polyether polyols such as those based on
ethoxylated and/or propoxylated aminomethylated nonylphenol derivatives.
These polyols are used in rigid polyurethane spray foams. Another example
is sucrose-based polyether polyols such as those based on sucrose
derivatives condensed with ethylene oxide and/or propylene oxide. These
polyols are used in rigid high and low density foams, for slabstock, froth
foams, and molded foams.
Examples of polyols used in polyurethane modified polyisocyanurate foams
include aromatic polyester polyols such as those based on complex mixtures
of phthalate-type or terephthalate-type esters formed from polyols such as
ethylene glycol, diethylene glycol, or propylene glycol. These polyols are
used in rigid laminated boardstock, can be blended with other types of
polyols such as sucrose based polyols, and used in other applications such
as molded polyurethane foams.
Examples of polyisocyanates include aromatic diisocyanates such as those
based on mixtures of 2,4- and 2,6-toluene diisocyanate. These
polyisocyanates are used in specialty foams. Another example is methylene
diphenyl diisocyanate (MDI) which typically contains 55% diphenylmethane
diisocyanates, 25% triisocyanates, and 20% higher polyisocyanates.
Any hydrofluorocarbon blowing agent may be used in the present invention.
Preferred hydrofluorocarbon blowing agents include 1,1-difluoroethane;
1,2-difluoroethane; 1,1,1-trifluoroethane; 1,1,2-trifluoroethane;
1,1,1,2-tetrafluoroethane; 1,1,2,2-tetrafluoroethane;
1,1,1,2,2-pentafluoroethane; 1,1,1,3-tetrafluoropropane;
1,1,2,3,3-pentafluoropropane; and 1,1,1,3,3-pentafluoro-n-butane.
Any hydrochlorofluorocarbon blowing agent may be used in the present
invention. Preferred hydrochlorofluorocarbon blowing agents include
1-chloro-1,2-difluoroethane; 1-chloro-2,2-difluoroethane;
1-chloro-1,1-difluoroethane; 1,1-dichlororo-1-fluoroethane;
1-chloro-1,1,2-trifluoroethane; 1-chloro-1,2,2-trifluoroethane;
1,1-dichoro-1,2-difluoroethane; 1-chloro-1,1,2,2-tetrafluoroethane;
1-chloro-1,2,2,2-tetrafluoroethane; 1,1-dichloro-1,2,2-trifluoroethane;
1,1-dichloro-2,2,2-trifluoroethane; and 1,2-dichloro-
1,1,2-trifluoroethane. The most preferred hydrochlorofluorocarbon blowing
agent is 1,1-dichloro-1-fluoroethane.
Mixtures of the preferred hydrohalocarbon blowing agents may also be used
in the present invention. Preferred mixtures of hydrohalocarbon blowing
agents include a mixture of 1,1-dichloro-1-fluoroethane with
1,1-dichloro-2,2,2-trifluoroethane and a mixture of
1,1-dichloro-2,2,2-trifluoroethane with
1,2-dichloro-1,2,2-trifluoroethane.
Examples of surfactants for polyurethane or polyurethane modified
polyisocyanurate foams are polyether modified polysiloxanes. These
silicone surfactants are typically non-hydrolyzable
siliconepolyoxyethylene/polyoxypropylene copolymers. Other examples
include non-silicon-containing organic surfactants which are proprietary
in structure. Tegostab.RTM.B-8404 is a silicone surfactant which is
available from Goldschmidt Chemical Company. Other commercially available
silicone surfactants include Tegostab.RTM.B-8404 which is available from
Goldschmidt Chemical Company, Dabco.RTM.DC-193 which is available from Air
Products and Chemicals, Inc., and L-5402.RTM. which is available from
Union Carbide. LK.RTM.-443 is an organic surfactant which is available
from Air Products and Chemicals, Ltd.
It will be evident to those skilled in the art that water may be included
in the polyurethane or polyurethane modified polyisocyanurate foam
formulations to generate carbon dioxide as a supplemental blowing agent by
reaction with polyisocyanate. In addition, water generated intermediates
can form cross-linked polymeric structures that may enhance physical
properties of the final product.
Examples of catalysts used for polyurethane foams include tertiary amines
such as triethylene diamine; N, N-dimethylethanolamine;
1,8-diaza-bicyclo(5.4,0) undecene-7; N,N-dimethylcyclohexylamine; and
2,4,6-tris(dimethylaminomethyl)phenol.
Examples of catalysts for polyurethane modified polyisocyanurate foams
include potassium 2-ethylhexanoate;
hexahydro-1,3,5-tris[3(N,N-dimethylamino)propyl]-1,3,5-triazine; and
N-2-hydroxypropyltrimethylammonium 2-ethylhexanoate. These are typically
used in conjunction with tertiary amine polyurethane catalysts.
Standard techniques known in the art for preparing foam may be used in the
present invention. Standard additives such as surfactants, water, and fire
retardants may also be used. Typically used ratios of polyisocyanate to
polyol and of blowing agent to these components may be used in practicing
the present invention.
The present invention also provides a process for preparing polyurethane or
polyurethane modified polyisocyanurate foams. The process comprises the
step of reacting polyol with polyisocyanate in the present of
hydrohalocarbon blowing agent, catalyst, surfactant, and at least one
additive. The at least one additive is capable of decreasing the amount of
decomposition of the hydrohalocarbon blowing agent during polymerization
of the polyisocyanate and the polyol. The present invention also provides
a polyurethane or polyurethane modified polyisocyanurate foam formed by
the foregoing process. The present invention also provides a polyurethane
or polyurethane modified polyisocyanurate article formed by the foregoing
process.
In another embodiment, the present invention also provides polyurethane
compositions and polyurethane modified polyisocyanurate compositions
comprising polyisocyanate, polyol, hydrohalocarbon blowing agent,
catalyst, surfactant, and at least two additives wherein each additive is
capable of decreasing the amount of decomposition of hydrohalocarbon to
haloalkenes during polymerization of the isocyanate and the polyol.
Preferably, the second additive is selected from the group consisting of
nitroalkanes; bromoalkanes; bromoalcohols; chloroalcohols; and
di(hydroxyalkyl) esters of tetrabromophthalic acid.
Preferred nitroalkanes are of the formula R.sup.1 R.sup.2 CH--NO.sub.2
where R.sup.1 is selected from the group consisting of hydrogen, alkyl
having 1 to 18 carbon atoms, cycloalkyl, substituted alkyl, aryl, and
substituted aryl and R.sup.2 is selected from the group consisting of
hydrogen and methyl. More preferred nitroalkanes include nitromethane;
nitroethane; 1-nitropropane; 2-nitropropane; 1-nitrobutane;
nitrocyclohexane; 1-nitrohexane; nitrocyclopentane; and 1-nitropentane.
The foregoing nitroalkanes are commercially available.
Preferred bromoalkanes are of the formula (Br).sub.a C(R.sup.1).sub.b
(R.sup.2).sub.c (R.sup.3).sub.d where a is 1, 2, 3, or 4 and a+b+c+c=4 and
R.sup.1, R.sup.2, and R.sup.3 are the same or different and selected from
the group consisting of hydrogen, linear alkyl having 1 to 18 carbon
atoms, substituted alkyl, haloalkyl, aryl, and substituted alkyl, More
preferred bromoalkanes include bromomethane; dibromomethane; carbon
tetrabromide; bromoform; 1,2-dibromobutane; 1,3-dibromobutane;
1,4-dibromobutane; 2,3-dibromobutane; 1,4-dibromo-2,3-butanediol; 2,3
-dibromo-1,4-butanediol; 1,4-dibromo-2-butanol; 1,4-dibromo-2-butene
1,10-dibromodecane; 1,2-dibromoethane; 1,12-dibromododecane;
(1,2-dibromoethyl)benzene; 1,7-dibromoheptane; and 1,6-dibromohexane. The
foregoing bromoalkanes are commercially available.
Preferred bromoalcohols are of the formula (Br).sub.a (H).sub.b
(R.sup.1).sub.c C--C(H).sub.d (R.sup.2).sub.e OH where a is 1, 2, or 3; c
is 0 or 1; a+b+c=3; d is 1 or 2; d+e=2; and R.sup.1 and R.sup.2 are the
same or different and selected from the group consisting of hydrogen,
alkyl having 1 to 18 carbon atoms, cycloalkyl, substituted alkyl,
hydroxyalkyl, aryl, and substituted aryl and when a=3 and d=e=1, R.sup.2
may also be OH or OR.sup.2 wherein R.sup.2 is alkyl having 1 to 18 carbon
atoms, cycloalkyl, substituted alkyl, and hydroxyalkyl, More preferred
bromoalcohols include 2,2,2-tribromoethanol; 2,2-dibromoethanol;
2-bromoethanol; 1,4-dibromo-2,3-butanediol; 2,3-dibromo-1,4-butanediol;
1,4-dibromo-2-butanol; 1,3-dibromopropanol; 2,3-dibromopropanol;
2,2,2-tribromo-1,1-dihydroxyethane; and 2,2,2-tribromo-1-methoxyethanol.
Many of the foregoing bromoalcohols are commercially available.
Preferred chloroalcohols are of the formula (Cl).sub.a (H).sub.b
(R.sup.1).sub.c C--C(H).sub.d (R.sup.2).sub.e OH where a is 1, 2, or 3; c
is 0 or 1; a+b+c=3; d is 1 or 2; d+e=2; and R.sup.1 and R.sup.2 are the
same or different and selected from the group consisting of hydrogen,
alkyl having 1 to 18 carbon atoms, cycloalkyl, substituted alkyl,
hydroxyalkyl, and aryl and when a=3 and d=e=1, R.sup.2 may also be OH or
OR.sup.2 wherein R.sup.2 is alkyl having 1 to 18 carbon atoms, cycloalkyl,
substituted alkyl, and hydroxyalkyl. More preferred chloroalcohols include
2,2,2-trichloroethanol; 2,2-dichloroethanol; 2-chloroethanol;
1,3-dichloro-2-propanol; 1,4-dichloroethanol; 2,3 -butanediol;
1,4-dichloro-2-butanol; 2,2-dichloro-1-pentanol; 1,1-dichloro-2-pentanol;
1-chloropentanol; 2-chloro-1-pentanol; 2-chloro-1-phenylethanol;
1-chloro | | |
