Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02243006 1998-08-24
TITLE
LOW DENSITY, LOW WATER ALL MDI FLEXIBLE FOAMS
FIELD OF THE INVENTION
The present invention relates to polyurethane compositions and more particularly to
polyurethane compositions employing diphenylmethane diisocyanates and polyols including a
relatively high ethylene oxide content to form relatively soft diphenyl"~elhane isocyanate foams.
BACKGROUND OF THE INVENTION
Compositions employing a reaction mixture of polyisocyanates with polyols in thepresence of catalysts and blowing agents to manufacture polyurethane foams have been known
for years. The polyisocyanates most commonly employed are generally either toluene
diisocyanates (TDl's), diphenylmethane diisocyanates (MDl's), or polymethylene polyphenylene
polyisocyanates (polymeric MDl's) depending largely upon the desired end product properties for
the resulting forms. For example, at a given water level, TDI formulations tend to result in lower
density foams than MDI fol " ,~ions. However, TDI is generally more expensive than MDI which is
reflected in the cost of the end products. Further, MDI or polymeric MDI based foams are often
preferable in terms of ease of manufacture, magnitude of load bearing latitude, and diversity of
product grade, among others.
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The polyol con,position employed in association with a given isocyanate also contributes
greatly to the properties of the foamed end product. For e,~dr",u e certain polyols such as those
containing high ethylene oxide/propylene oxide ratio heterics are known to cause cell opening
which is often desirable. However such polyols lead to higher density foams which is often
undesirable.
Thus there is a need in the art for polyurethane foam col"posilions which employ MDI
and/or poloymeric MDI but give rise to foams having relatively low densities as are achieved
utilizing TDI.
SUMMARY OF THE INVENTION
In view of the apparent need in the art for low density foams producible using relatively low
water levels and MDI or polymeric MDI co",positions according to one aspect the present
invention relates to a polyurethane foam col"~risi"g the reaction mixture of:
a) an isocyanate reactive cor"ponent including a polyol blend col"prisil~g at least one
ethylene oxide/propylene oxide heteric polyol and at least one ethylene oxide capped polyol
2 0 wherein the polyol blend has an average hydroxyl equivalent weight of at least about 1500;
b) a catalyst;
c) a blowing agent consi~ling of water;
d) a crosslinker;
e) optionally a surface active agent; and
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f) an isocyanate composition wherein the resulting foam has an average density of
less than about 3.5 pcf.
According to a second aspect the present invention relates to a resin useful for the
production of polyurethane foams co" ,prisi"y.
a) an isocyanate reactive component including a polyol blend cor"~ i"g at least one
ethylene oxide/propylene oxide heteric polyol and at least one ethylene oxide capped polyol
wherein the polyol blend has an average hydroxyl equivalent weight of at least about 1500;
b) a catalyst;
c) a blowing agent consisting essentially of water;
d) a crosslinker; and
e) optionally a surface active agent.
Surprisingly it was discovered that polyurethane foams produced by reacting an MDI
composition with a blended polyol including both ethylene oxide and propylene oxide heterics and
at least one ethylene oxide capped polyol gave rise to foams having a relatively low density i.e.
below about 2.8 pcf. Generally an ethylene oxide heteric polyol added to a resin co",posilion will
result in poly~"~ll,ane foams having a higher density than those foams which employ polyols
having little or no ethylene oxide heteric polyol.
DETAILED DESCRIPTION OF THE INVENTION
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The foams provided in accordance with the teachings of the present invention are low
density, low water, MDI flexible urethane foams. The foams are polyisocyanate based meaning
that they are made by reacting the reactive ingredients in a polyol composition with an organic
isocyanate.
The polyol composition co",pri~es a blended polyol including at least one ethylene
oxide/propylene oxide heteric polyol and at least one ethylene oxide capped polyol, water as a
blowing agent, a polyurethane linkage plO~ lil ,9 catalyst, a surfactant, and optionally fillers, flame
rela,darll~, stabilizers, fungicides, and bacteriostats.
Turning to the ingredients of the polyol composition, there is provided a polyol blend
including at least one ethylene oxide/propylene oxide heteric polyol and at least one ethylene
oxide capped polyol wherein the polyol blend has a weight average molecular weight of greater
than 4200 and, more pref~r~bly, between about 4700 to about 6800. The polyol blend has an
average hydroxyl number ranging from 20 to 60 mgKOH/g and an average functionality of at least
2Ø In a preferred embodiment, the polyol blend will have an average hydroxyl number ranging
from about 25 to about 45 mgKOH/g and an average functionality of at least 3Ø
Preferably, the amount of ethylene oxide/propylene oxide heteric polyol employed in the
blend will be between about 8.0 wt. % to about 30.0 wt. %, more pr~fel~bly 10.0 wt. % to about
20.0 % and still more pr~rer~bly, between about 12.0 wt. % to about 16.0 wt. %. The amount of
ethylene oxide capped polyol employed in the polyol blend will preferably be between about 18.0
wt. % to about 24.0 wt. % and still more pr~:r~rably, between about 20.0 wt. % to about 22..0 wt.
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5 %. Thus, the total amount of the ethylene oxlde/propylene oxide heteric polyol and the ethylene
oxide capped polyol will be at least 26.0 wt. % based on the total amount of the poiyol blend.
Exdl",-'es of useful polyols which may be employed in addition to the above described
polyols include polythioether polyols, polyester amides and polyacetals containing hydroxyl
groups, aliphatic polyca,L,onaL~s containing hydroxyl groups, amine temminated polyoxyalkylene
10 polyethers, and preferably, polyester polyols, polyoxyalkylene polyether polyols, and graft
dispersion polyols.
The term "polyester polyol" as used in this specification and claims includes any minor
amounts of unreacted polyol remaining after the pr~pa,~Lion of the polyester polyol and/or
unesterified polyol (e.g., glycol) added after the preparation of the polyester polyol. The polyester
15 polyol can include up to about 40 weight percent free glycol.
Suitable polyester polyols can be produced, for example, from organic dicarboxylic acids
with 2 to 12 carbons, prefel~bly aliphatic dicarboxylic acids with 4 to 6 carbons, and multivalent
alcohols, preferably diols, with 2 to 12 carbons, p,~fer~bly 2 to 6 carbons. Exd",r'es of
dicarboxylic acids include suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, maleic
2 0 acid, fumaric acid phthalic acid, isophthalic acid, and terephLI ,alic acid. The dicarboxylic acids can
be used individually or in mixtures, Instead of the free dicarboxylic acids, the co"esponding
dicarboxylic acid derivatives may also be used such as dicarboxylic acid mono- or di- esters of
alcohols with 1 to 4 carbons, or dicarboxylic acid anhydrides. Dicarboxylic acid mixtures of
succinic acid, glutaric acid and adipic acid in quantity ratios of 20 - 35: - 35 - 50:20 - 32 parts by
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weight are prel~r,~d, especially adipic acid. Examples of divalent and multivalent alcohols,
especially diols, include ethanediol, diethylene glycol, 1,2- and 1,3-propanediol, dipropylene
glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,10-decanediol, glycerine and
trimethylolpropanes, tripropylene glycol, tetraethylene glycol, tetrapropylene glycol, tel,d,~,~ll,ylene
glycol, 1,4-cyclohexane-dil"ell,anol, ethanediol, diethylene glycol, 1,4-butanediol, 1,5-pentanediol,
1,6-hexanediol, or mixtures of at least two of these diols are preferred, especially mixtures of 1,4-
butanediol, 1,5-pentanediol, and 1,6-hexanediol. Furthermore, polyester polyols of lactones, e.g.,
ecaprolactone or hydroxycarboxylic acids, e.g., aromatic or prer~,ably aliphatic polycdrL,onxylic
acids and/or derivatives thereof and multivalent alcohols in the absence of catalysts or prererdbly
in the presence of esterification catalysts, preferably in an atmosphere of inert gases, e.g.,
nitrogen, carbon dioxide, helium, argon, etc., in the melt at temperatures of 150~ to 250~ C,
pr~f~ldbly 180~ - 220~ C, optionally under reduced pressure, up to the desired acid value which is
preferably less than 10, especially less than 2. In a preferred embodi",e"t, the esterification
mixture is subjected to polycondensation at the temperatures mentioned above up to an acid
value of 80 to 30, preferably 40 to 30, under normal pressure, and then under a pressure of less
2 0 than 500 mbar, prt:rer~bly 50 to 150 mbar. The reaction can be carried out as a batch process or
continuously. When present, excess glycol can be distilled from the reaction mixture during
and/or after the reaction, such as in the preparation of low free glycol-containing polyester polyols
usable in the present invention. Exdr"ples of suitable esterification catalysts include iron,
cadmium, cobalt, lead, zinc, anli"~ony, magnesium, titanium and tin catalysts in the form of
-
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5 metals, metal oxides or metal salts. However, the polycondensation may also be perfommed in
liquid phase in he presence of diluents and/or chlorobenzene for a,iol,u,..c distillation of the water
of condensation.
To produce the polyester polyols, the organic polycarboxylic acids and/or derivatives
thereof and multivalent alcohols are preferably polycondensed in a mole ratio of 1:1 - 1:8, more
1 0 preferably 1 :1 .05 -1 .2.
After transesterification or esterification, the reaction product can be reacted with an
alkylene oxide to form a polyester polyol mixture. This reaction desirably is catalyzed. The
temperal.lre of this process should be from about 80~ C to about 170~ C, and the pressure should
generally range from about 1 to 40 atmospheres.
While the aromatic polyester polyols can be prepared from sub~la,ltially pure reactant
materials, more complex ingredients can be used, such as the side stream, waste or scrap
residues from the manufacture of phthalic acid, terephthalic acid, dimethyl terephthalate,
polyethylene terephthalate, and the like. Compositions containing phthalic acid residues for use in
the invention are (a) ester-containing byproducts from the manufacture of dimethyl ter~phll,alale,
2 0 (b) scrap polyalkylene terephthalates, (c) phthalic anhydride, (d) residues from the manufacture of
phthalic acid or phthalic anhydride, (e) therephthalic acid, (fl residues from the manufacture of
terephthalic acid, (g) isophthalic acid, (h) trimellitic anhydride, and (i) comb.. ,~lions thereof. These
compositions may be converted by reaction with the polyols of the invention to polyester polyols
through conventional transesterification or e~ ri~icalion procedures.
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Other materials containing phthalic acid residues are polyalkylene terephll ,alates,
especially polyethylene terephthalate (PET), residues or scraps. Still other residues are DMT
process residues, which are waste or scrap residues from the manufacture of dimethyl
te,~pl,ll,alate (DMT).
Polyoxyalkylene polyether polyols, which can be obtained by known methods, are
preferred for use as the polyhydroxyl compounds. For example, polyether polyols can be
produced by anionic polymerization with alkali hydroxides such as sodium hydroxide or potassium
hydroxide or alkali alcoholates, such as sodium methylate, sodium ethylate, or potassium ethylate
or potassium isopropylate as catalysts and with the addition of at least one initiator molecule
containing 2 to 8, preferably 3 to 8, reactive hydrogens or by cationic polymeri,alion with Lewis
acids such as anli",ony pentachloride, boron trifluoride etherate, etc., or bleaching earth as
catalysts from one or more alkylene oxides with 2 to 4 carbons in the alkylene radical. Any
suitable alkylene oxide may be used such as 1,3-propylene oxide, 1,2- and 2,3-butylene oxide,
amylene oxides, styrene oxide, and preferably ethylene oxide and 1,2-propylene oxide and
mixtures of these oxides. The polyalkylene polyether polyols may be prepared from other starting
",~lerials such as tetrahydrofuran and alkylene oxide-tetrahydrofuran mixtures; ,ep'.',-'chydrins
such as epicl,'cruhydrin; as well as aralkylene oxides such as styrene oxide. The polyalkylene
polyether polyols may have either primary or secondary hydroxyl groups.
Included among the polyether polyols are polyoxyethylene glycol, polyoxypropylene glycol,
polyoxybutylene glycol, polytetramethylene glycol, block copolymers, for example, combinations
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5 of polyoxypropylene and polyoxyethylene glycols, poly-1,2-oxybutylene and polyoxyethylene
glycols, poly-1,4-tetramethylene and polyoxyethylene glycols, and copolymer glycols prepared
from blends or sequential addition of two or more alkylene oxides. The polyalkylene polyether
polyols may be prepared by any known process such as, for example, the process disclosed by
Wurtz in 1859 and Encyclopedia of Chemical Technology, Vol. 7, pp. 257 - 262, published by
Interscience Publishers, Inc. (1951) or in U.S. Pat. No. 1,922,459.
Polyethers which are preferred include the alkylene oxide addition products of polyhydric
alcohols such as ethylene glycol, propylene glycol, dipropylene glycol, trimethylene glycol, 1,2-
butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, hydroquinone, resorcinol glycerol,
glycerine, 1,1,1- trimethylol-prupane, 1,1,1-trimethylolethane, pentaerythritol, 1,2,6-hexanetriol, a-
15 methyl glucoside, sucrose, and sorbitol. Also included within the term "polyhydric alcohol" arecompounds derived from phenol such as 2,2-bis(4 hydroxyphenyl)-propane, co"""only known as
Bisphenol A.
Suitable ûrganic amine initiators which may be condensed with alkylene oxides include
aromatic amines such as aniline, N-alkylphenylene-diamines, 2,4'-, 2,2'-, and 4,4'-
2 0 methylenedianiline, 2,6- or 2,4-toluenediamine, vicinal toluenediamines, o-chloro-aniline,
paminoaniline, 1,5-diaminonaphthalene, methylene dianiline, the various condensation products of
aniline and formaldehyde, and the isomeric diami"ot~'uenes; and aliphatic amines such as mono,
di-, and trialkanolamines, ethylene diamine, propylene diamine, diethylenetliar,line, methylamine,
ethanolamine, diell ,anolar, line, N-methyl and N-ethylethanolamine, N-methyl- and N-
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5 ethyldiethanolamine, triethanolamine, lli;sop~upanolarlline~ 1,3-diaminoprupane, 1,3-
diaminobutane, and 1,4-diaminobutane. Preferable amines include mono- and diethanolamine,
vicinal toluenediamines, ethylenediamines, and propylenediamine. in a particularly pr~fer,ed
embodiment, at least one of the polyether polyols employed is initiated with an initiator containing
or consisli"g of an aliphatic amine, and more preferably, all of the polyols used are initiated with
10 an initiator containing an amine, most preferably an aliphatic amine. It is to be understood that the
polyols initiated by an amine can also be initiated with a polyhydric alcohol, such as when a mixed
initiator of an aliphatic amine/polyhydric alcohol is used like an amine/sucrose package.
Suitable polyhydric polythioethers which may be condensed with alkylene oxides include
the condensation product of thiodiglycol or the reaction product of a dicarboxylic acid such as is
15 disclosed above for the preparation of the hydroxyl-containing polyesters with any other suitable
thioether glycol.
The hydroxyl-containing polyester may also be a polyester amide such as is obtained by
including some amine or amino alcohol in the reactants for the preparation of the polyesters.
Thus, polyester amides may be obtained by condensing an amino alcohol such as ethanolamine
20 with the polycarboxylic acids set forth above or they may be made using the same components
that make up the hydroxyl-containing polyester with only a portion of the components being a
diamine such as ethylene diamine.
Polyhydroxyl-containing phosphorus compounds which may be used include those
compounds disclosed in U.S. Pat. No. 3,639,542. Preferred polyhydroxyl-containing phosphorus
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5 compounds are prepared from alkylene oxides and acids of phosphorus having a P2O5
equivalency of from about 72 percent to about 95 percent.
Suitable polyacetals which may be condensed with alkylene oxides include the reaction
product of formaldehyde or other suitable aldehyde with dihydric alcohol or an alkylene oxide such
as those disclosed above.
Suitable aliphatic thiols which may be condensed with alkylene oxides include . "~anetl,.~'s
containing at least two -SH groups such as 1,2-ethanedithiol, 1,2-propanedithiol, 1,2-
propanedithiol, and 1,6-hexanedithiol; alkene thiols such as 2-butene-1,4-dithiol; and alkyne thiols
such as 3-hexyne-1,6-dithiol.
Also useful in association with the polyol blend co",prisi"g at least one ethylene
oxide/propylene oxide heteric polyol and at least one ethylene oxide capped polyol are polymer
modified polyols, in particular, the so-called graft polyols. Graft polyols are well known to the art
and are prepared by the in situ polymerization of one or more vinyl monomers, preferably
acrylonitrile and styrene, in the presence of a polyether or polyester polyol, particularly polyols
containing a minor amount of natural or induced unsaturation. Methods of prt:pari"g such graft
polyols may be found in columns 1 - 5 and in the Examples of U.S. Pat. No. 3,652,639; in
columns 1 - 6 and the Exdlllp'Es of U.S. Pat. No. 3,823,201; particularly in columns 2 - 8 and the
Examples of U.S. Pat. No. 4,690,956; and in U.S. Pat. No. 4,524,157; all of which patents are
herein incorporated by reference.
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Non-graft polymer modified polyols such as those prepared by the reaction of a
polyisocyanate with an alkanolamine in the presence of a polyol as taught by U.S. Pat. Nos.
4,293,470; 4,296,213; and 4,374,209; dispersions of polyisocyanurates containing pendant urea
groups as taught by U.S. Pat. No. 4,386,167; and polyisocyanurate dispersions also containing
biuret linkages as taught by U.S. Pat. No. 4,359,541 are also useful.
As a blowing agent, water is employed. The amount of water will at least in part depend
upon the desired foam density. For the foams of the present invention, suitable free rise
densities are greater than 1.7 pcf to less than about 3.5 pcf, pr~:ferdbly 2.0 pcf to 2.5 pcf. To
satisfy these density limitations, the amount of water utilized in TDI foam formulations is typically
in the range of 2.5 to about 4.4 pbw, preferably from 3.2 pbw to 4.2 pbw, more pr~fe,ably from 3.5
pbw to 3.9 pbw, based on 100 pbw of the isocyanate reactive component. Water is useful as a
blowing agent in that it reacts with the organic isocyanate to produce urea linkages and liberate
carbon dioxide gas. However, it has been discovered that the amount of water el n~ 'oyed must be
carefully controlled since higher water levels generate more urea linkages and thus result in
harder foams generally.
Catalysts may be employed which greatly accelerdte the reaction of the compoundscontaining hydroxyl groups and with modified or unmodified polyisocyanates. Examples of
suitable compounds are cure catalysts which also function to shorten tack time, promote green
strength, and prevent foam shrinkage. Suitable cure catalysts are organometallic catalysts,
pr~:fer~bly organorin catalysts, although it is possible to employ metals such as lead, titanium,
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5 copper, mercury, cobalt, nickel, iron, vanadium, anli~ ~ ~ony, and n ,anyanese. Suitable
oryanon,~lallic catalysts, exemplified here by tin as the metal, are repr~sented by the formula:
RnSn[X-R~ -y2, wherein R is a C~ - C8 alkyl or aryl group, R1 is a C0- C,8 methylene group
optionally substituted or branched with a C1-C4 alkyl group, Y is hydrogen or an hydroxyl group,
preferably hydrogen, X is methylene, an -S-, an -SR2COO-, -SOOC-, an -O3S-, or an -OOC-
group wherein R2 is a C1-C4 alkyl, n is 0 or 2, provided that R1 is C0 only when X is a methylene
group. Specific examples are tin (Il) acetate, tin (Il) o~;lanoale, tin (Il) ethylhexanoate and tin (Il)
laurate; and dialkyl (1 - 8C) tin (IV) salts of organic carboxylic acids having 1 - 32 carbon atoms,
preferably 1 - 2- carbon atoms, e.g., diethyltin diacetate, dibutyltin diacetate, dibutyltin diacetate,
dibutyltin dilaurate, dibutylli"",-'e?ite, dihexyltin diacetate, and dioctyltin diacetate. Other suitable
organotin catalysts are oryanoli" aloxides and mono or polyalkyl (1 - 8C) tin (IV) salts of i"oryan.c
compounds such as butyltin l,ichloride, dimethyl- and diethyl - and dibutyl- and diocryl- and
diphenyl- tin oxide, dibutyltin dibutoxide, di(2-ethylhexyl) tin oxide. Preferred, however, are tin
catalysts with tin-sulfur bonds which are resistant to hydrolysis, such as dialkyl (1 - 20C) tin
dimercaptides, including dimethyl-, dibutyl-, and dioctyl- tin di",ercaptides.
Tertiary amines also pro",ule urethane linkage fo""~tion, and include triethylamine, 3-
- methoxypropyl-dimethylamine, triethylenediamine, tributylamine, dimethylcyclohexylamine,
dimethylbenzylamine, N-methyl-, N-ethyl- and N-cyclohexyl~ "o",holine, N,N,N',N'-
tet,~l"ett,ylethylenediamine, N,N,N',N'-tetramethylbutanediamine or -hexanediamine, N,N,N'-
trimethyl isopropyl propylenediamine, penlal"~ll,yldiethylenetriamine,
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~et, ~mell ,yldiaminoethylether, bis(-dimethylaminopropyl)urea, dimethylpiperazine, 1 -methyl-4-
dimethylaminoethylpiperazine, 1,2-dimethylirn:l ~le, 1-azabicylo[3.3.0] octane and prefer~bly
1,4~iazabicylo[2.2.2] octane, and alkanolamine compounds, such as trie~l,anola"line,
triisopropanolamine, N-methyl- and N-ethyldie, I ,anola" line and dimethyl~,;l ,anolamine.
In a pr~r~r,~d embodiment, a delayed action tertiary amine gel catalyst is employed to
10 pru",ote improved froth flow characteristics. Any of the above tertiary amines can be employed.
Exdnlr'es of suitable organic acid blocked amine gel catalysts are the acid blocked amines of
triethylenediamine, N-ethyl or methyl morpholine, N,N dimethylamine, N-ethyl or methyl
morpholine, N,N dimethylaminoethyl morpholine, N-butyl~ "or~holine, N,N' dimethylpiperazine,
bis(dimethylamino-alkyl)-piperazines, 1,2 dimethyl i",:~- ~le, dimethyl cyclohexylamine. The
15 blocking agent can be an organic carboxylic acid having 1 to 20 carbon atoms, preferably 1 - 2
carbon atoms. Ex~r"ples of blocking agents include 2-ethyl-hexanoic acid and formic acid. Any
stoic',.on,el,ic ratio can be employed with one acid equivalent blocking one amine group
equivalent being preferred. The tertiary amine salt of the organic carboxylic acid can be fommed in
situ, or it can be added to the polyol composition ingredients as a salt.
The polyol composition optionally contains a flame ,t:tarda"L. Exalll~'os of suitable
phosphate flameproofing agents are tricresyl phosphate, tris(2-cl,loruell,yl)phosphate, tris(2-
ch'uropr~.pyl) phosphate, and tris(2,3-dibrolnorJIupyl) phosphate. In addition to these halogen
substituted phosphates, it is also possible to use inorganic or organic flameprùuri,,g agents, such
as red phosphorus, aluminum oxide hydrate, anlilllony trioxide, arsenic oxide, a",monum
14
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5 polyphosphate (Exolit~E3)) and calcium sulfate, molybdenum trioxide, am",on-lrn molybdate,
a" 1" ,on - ~rn phosphate, penl~bru~ "odiphenyloxide, 2,3-dibr~," ,opropanol,
he,cabrulnoc;yclododecane, dibromoethyldibromocyclohexane, expandable g,~ hite or cyanuric
acid derivatives, e.g., melamine, or mixtures of two or more flar"epr~ ofing agents, e.g.,
al"",on-~rn polyphosph~les and melamine, and, if desired, com starch, or an""on ~rn
10 polyphosphate, melamine, and expandable graphite and/or, if desired, aromatic polyesters, in
order to flameproof the polyisocyanate polyaddition products. In general, from 2 to 40 weight
percent, preferably from 5 to 20 weight percent, of said flameproofing agents may be used based
on the weight of the isocyanate reactive composition.
Examples of suitable surfactants are compounds which serve to support homogenization
15 of the starting ~ lerials and may also regulate the cell structure of the plastics. Specific exdn ,, le s
are salts of sulfonic acids, e.g., alkali metal salts or a~",llon um salts of fatty acids such as oleic or
stearic acid, of didecylbenzene or dinaphthylmethanedisulfonic acid, and ricinoleic acid, foam
stabilizers, such as siloxaneoxyalkylene copolymers and other organopoly- !'cxanes, oxyethyiated
alkyl-phenols, oxyethylated fatty a'~ohGls, paraffin oils, ~astor oil esters, ricinoleic acid esters,
20 Turkey red oil and groundnut oil, and cell regulators, such as pardrri"s, fatty alcohols, and
dimethylpolysiloxanes. The surfactants are usually used in amounts of 0.01 to 5 wt. %, based on
the weight of the polyol col "posiLion.
The organic polyisocyanates employed include 2,2'-diphenyllllelhane diisocyanate and the
corresponding isomeric mixtures, mixtures of 4,4'- and 2,4'-diphenylmethane diisocyanates and
CA 02243006 1998-08-24
5 polyphenylenepolymethylene polyisocyanates (polymeric MDI). In addition, other organic
polyisocyanates including aliphatic, cycloaliphatic, araliphatic and preferably aromatic multivalent
isocyanates may be employed in limited amounts. Specific examples of optional polyisocyanates
include: alkylene diisocyanates with 4 to 12 carbons in the alkylene radical such as 1,12-
dodecane diisocyanate, 2-ethyl-1,4-tetramethylene diisocyanate, 2-methyl-1,5-pentamethylene
10 diisocyanate, 1,4-tel,d",t:ll,ylene diisocyanate and preferdbly 1,6-hexd",~lhylene diisocyanate;
cycloaliphatic diisocyanates such as 1,3- and 1,4- cyclohexane diisocyanate as well as any
mixtures of these isomers, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyulohexane
(isophorone diisocyanate), 2,4- and 2,6-hexahyd, ul ~ 'Lene diisocyanate as well as the
corresponding isomeric mixtures, 4,4'-2,2'-, and 2,4'-dicyclohexylmelhane diisocyanate as well as
15 the corresponding isomeric mixtures and preferably arumatic diisocyanates and polyisocyanates
such as 2,4- and 2,6-toluene diisocyanate. The organic di- and polyisocyanates can be used
individually or in the form of mixtures. However, the organic polyisocyanate component will
include at least about 15.0 weight percent MDI and/or polymeric MDI.
Frequently, so-called modified multivalent isocyanates, i.e., products obtained by the
20 partial chemical reaction of organic diisocyanates and/or polyisocyanates may also be employed
to a limited extent. Exd",,'es include diisocyanates and/or polyisocyanates containing ester
groups, urea groups, biuret groups, ."~Fhandle groups, carbodiimide groups, isocyanurate
groups, and/or urethane groups. Specific exdl"~'-s include organic, preferably arur"dlic,
polyisocyanates containing urethane groups and having an NCO content of 33.6 to 15 weight
16
CA 02243006 1998-08-24
percent, preferably 31 to 21 weight percent, based on the total weight, e.g., with low ~"n'ecl~
weight diols, triols, dialkylene glycols, trialkylene glycols, or polyoxyalkylene glycols with a
Illc'ecu~ar weight of up to 1500; modified 4,4'-diphenyl"~lhane diisocyanate or 2,4- and 2,6-
toluene diisocyanate, where exal",~'es of di- and polyoxyalkylene glycols that may be used
individually or as mixtures include diethylene glycol, dipropylene glycol, polyoxyethylene glycol,
polyoxypropylene glycol, polyoxyethylene glycol, polyoxypropylene glycol, and polyoxypropylene
polyoxyethylene glycols or-triols. Prepolymers containing NCO groups with an NCO content of
25 to 9 weight percent, pr~ferdbly 21 to 14 weight percent, based on the total weight and
produced from the polyester polyols and/or preferably polyether polyols described below; 4,4'-
diphenylmethane diisocyanate, mixtures of 2,4'- and 4,4'-diphenyl~"t:ll,ane diisocyanate, 2,4-
and/or 2,6-toluene diisocyanates or polymeric MDI are also suitable. Furthermore, lipid
polyisocyanates containing carbodi;n,de groups having an NCO content of 33.6 to 15 weight
percent, preferably 31 to 21 weight percent, based on the total weight, have also proven suitable,
e.g., based on 4,4'- and 2,4'- and/or 2,2'-diphenylmethane diisocyanate and/or 2,4'- and 4,4'-
diphenyl~ ll,ane diisocyanate, polymeric MDI, 2,4'- and/or 2,6-toluene diisocyanate.
2 0 Crude polyisocyanates may also be used to a relatively limited extent in the co,npositions
of the present invention, such as crude toluene diisocyanate obtained by the phosgendlion of a
mixture of toluenediamines or crude diphenylmethane isocyanate obtained by the phosgenation of
crude diphenyl~"~ll,ane diamine. The preferred or crude isocyanates are disclosed in U.S. Pat.
No. 3,215,652.
CA 02243006 1998-08-24
The following examples illustrate the nature of the invention and should not be considered
as limitations thereto. Unless otherwise indicated, all parts are expressed in parts by weight.
Polyol A is a propylene oxide, ethylene oxide, glycerine adduct containing 21 weight
percent ethylene oxide, having a theoretical functionality of 3.0, and a hydroxyl number of 27.5.
Polyol B is a propylene oxide, ethylene oxide, trimethylol propane adduct containing 78
weight percent ethylene oxide, having a theoretical functionality of 3.0 and a hydroxyl number of
24Ø
Polyol C is a propylene oxide, ethylene oxide, glycerine adduct containing 73 weight
percent ethylene oxide, having a theoretical functionality of 3.0 and a hydroxyl number of 46Ø
B4113 is a silicone surfactant available from Goldschmidt.
Polycat 77 is an amine catalyst available from Air Products.
SA 610 50 is an amine catalyst available from Air Products.
ISO A is a polymeric MDI having a viscosity of about 30 cps at 25~ C, a nominal
functionality of 2.2, a monomeric MDI content of about 78% and an NCO content of about 32.3%.
To evaluate the cell opening characteristics for foam formulations including varying
amounts of high ethylene oxide capped and heteric polyols three dirrerenl formulations pr~pa,ed
as set forth in Table ll below were analyzed as free use cups. Each of the samples 1-3 were
identical except for the type of polyol employed as set forth in Table 1.
CA 02243006 1998-08-24
TABLE I
Sample A B C
Polyol A 96.05 -- --
Polyol B 96.05
Polyol C 96.05
water 2.85 2.85 2.85
B4113 .25 .25 .25
Polycat 77 .60 .60 .60
SA 610 50 .25 .25 .25
To prepare the samples set forth in Table ll, the required weights of the resinslisted in Table I were added separately to 23.6 grams of ISO A utilizing standard mix
techniques including a German mix blade at 3100 rpm at a quart cup factor of 0.059.
TABLE ll
Sample Sample 2 Sample 3
Resin A50.0 9 40.0 g 40.0 9
Resin B -- 10.0 9
Resin C 10.0 g
ISO A 23.6 9 23.6 9 23.6 9
CA 02243006 1998-08-24
The reaction profile for Sample 1 showed a cream time of 14 sec., a top of cup
time of 58 sec., a string gel time of 70 sec., and an end rise time of 94 sec. To calculate
the density, the net weight of the cup 55.49 9 was multiplied by the cup factor 0.059
giving a density of 3.218 pcf.
10The reaction profile for Sample 2 showed a cream time of 14 sec., a top cup time
of 55 sec., a string gel time of 65 sec., and an end rise time of 104 sec. Surprisingly, the
cup net weight fell to 50.9 9 thereby giving a calculated density of 50.9 * 0.059 = 3.003
pcf.
The reaction profile of Sample 3 showed a cream time of 14 sec., a top of cup time
15of 55 sec., a string gel time of 65 sec., and an end rise time of 104 sec. Again, the cup
net weight fell unexpectedly to 48.77 g resulting in a calculated density of 48.77 9 1 0.059
=2.88pcf.
