Note: Descriptions are shown in the official language in which they were submitted.
--1--
USE OF LOW MOLECULAR WEIG~
POLYHYDROXY COMPOUNDS IN M:ETHYLENE
C~ILORIDE BLOWN POLYURETHAN$ FOAMS
In recent months the conventional blowing
agents, the fluorocarbons, e.g., fluorotrichloromethane,
have come under attack from environmentalists. The ure-
thane foam industry, which has had very good results
using these agents, has had to use other blowing agents
to replace all or part of the conventional fluorocarbons.
The logical choice was methylene chlorlde, a blowing
agent which has been used by industry on a selective
basis a-t lower concentrations in the past. The urethane
foam industry found that methylene chloride was not a
suitable blowing agent at higher concentrations because
it required excessive amounks of gelation catalysts to
ix the urethane in its risen or foam state prior to
final cure, and these increased amounts of gelation
catalyst reduced processing flexibility. The practice
today is to use a co-blowing agent with the methylene
chloride, or to use large amounts of the gelling cata-
lyst. As a result, the industry has used the methylene
chloride sparingly.
28,037-F -1-
The present lnvention is a method for prepar-
ing a polyurethane oam by reacting a polyether polyol
having a molecular weight of from 800 to 5000, an isocya-
nate, water, a metal salt ca-talyst, an amine catalyst, a
silicone surfactant and a halogenated hydrocarbon blowing
agent, which blowing agent is at least 10 percent methyl-
ene chloride, characterized by incorporating with the
reactants from 0.1 to 1.5 parts of a polyhydroxy aliphatic
compound having more than two hydroxyl groups and a molec-
ular weight of not more than 195, while employing from1.4 to 1.6 times the metal salt catalyst of that used
where a fluorocarbon is the sole blowing agent.
Surprisingly it has been found that by the
incorporation of the polyhydroxy aliphatic compound of
the type above-described the foam is pre-set with only
slightly more metal salt catalyst than is commonly
employed when using a fluorocarbon blowing agent alone.
The proportions of the metal catalysts can vary over
almost as wide a range when employing the meth~lene chlo-
ride and the polyhydroxy compounds o~ the present inven-
tion, and yet obtain a high quality, very soft foam, as
when one employs only the fluorocarbons, the standard of
the industxy. In addition, the amount of metal cakalyst
is reduced by as much as 30 percent over that required
to obtain an equivalent foam from a ~ormulation employing
methylene chloride, as a replacement for a part or all of
the conventional fluorocarbon blowing agents, wi-thout the
polyhydroxy compound of the present invention.
The process according to the invention is
preferably carried out utlliæing the same components
commercially ernployed in the manufacture of polyurethane
28,037-F 2-
-- 3 --
foams except Eor the s~bstitution oE methylene chlo~i~e
for all or apart o~ the conventional 1uorocar~on blo~~
ing agent by the addition of small amounts o~ a poly-
hydroxy compound as hereinafter defined. The combination
permits the use of less gelation catalyst than previously
necessary to obtain a foam, although denser or less soft.
It is to be understood that the optional components o
commercial formulations such as fillers, activators, sta-
biliziers and pigments may likewise be employed.
The polyol components used are known and are
preferably polyethers having molecular weight of from
800 to 5000 and preferably from 2500 to 4500. They can
be used in admixture with low molecular weight polyols
and with the addition of activators and blowing agents.
Mineral fillers, foam stabilizers, anti-agers and simi-
lar additives of the kind normally used in polyurethane
chemistry may also be added to the polyols. The poly-
ethers suitable for use include those obtained by polym-
erizing tetrahydrofuran or epoxides suchas ethylene
oxide, propylene oxide, butylene oxide, styrene oxide or
epichlorohydrin in the presence of a catalyst such as
BF3, or by adding these epoxides in admi~ture or in suc-
cession to starter components containing reactive hydro-
gen atoms such as water, alcohols or amines. Suitable
starter components inclwde ethylene glycol, 1,3-propylene
glycol, 1,2-propylene glycol, trimethylol propane, 4,41_
-dihydroxy dipehnyl propane, aniline, ammonia, ethanol-
amine, ethylenediamine and water. Sucrose polyethers
of the type described in U.S. Patent 2,927,918 may
also be used in accordance with the invention.
In manycases, it is preferred to use polyethers
of the type generally known which contain sub-
stantial amounts of primary OH groups (up to 90 percent
28,037-F - 3 -
,~ ,
by weight, based on all the OH groups present in the
polyether). Polyethers modified with vinyl polymers of
the type formed by polymerizing styrene and acrylonitrile
in the presence of polyethers are also suitable as are
polybutadie~es containing O~ groups.
Instead of using polyethers, it is al~o pos-
sible, as is recognized in the polyurethane art, to uti-
lize polyesters, polythioethers, polyacetals, polycarbon-
ates, polyester amides, or mixtures thereof, having
molecular weights in the range from 400 to 10,000 and
preferably from 1000 to 6000.
The polyesters containing hydroxyl groups
suitable for use include the reaction products of poly-
hydric (preferably dihydric and optionally trihydric)
alcohols with polyvalent (preferably divalent) carbox-
ylic acids. Instead of using the free polycarboxylic
acids, it is also possible to use the corresponding poly-
carboxylic acid anhydrides or corresponding polycarbox-
ylic acid esters of lower alcohols or mixtures thereof
for producing the polyesters. The polycarboxylic acids
may be aliphatic, cycloaliphatic, aromatic and/or hetero-
cyclic and may be substituted (e,g., with halogen atoms)
and/or unsaturated. Examples of carboxylic acids and
anhydrides of this kind include succinic acid, adipic
acid, suberic acid, azelaic acid, sebacic acid, phthalic
acid, isophthalic acid, trimellitic acid, phthalic acid
anhydride, tetrahydrophthalic acid anhydride, hexahydro
phthalic acid anhydride, tetrachlorophthalic acid anhy-
dride, endomethylene tetrahydrophthalic acid anhydride,
glutaric acid anhydride, maleic acid, maleic acid anhy-
drida, fumaric acid, dimeric and trimeric fatty acids,
28,037-F -4-
-5-
such as oleic acid, which may be in admixture with mono-
meric fatty acids, terephthalic acid dimethyl ester and
terephthalic acid bisglycol estar. Examples of suitable
polyhydric alcohols include ethylene glycol, 1,2-propyl-
ene glycol, 1,3-propylene glycol, 1,4- and 2,3-butylene
glycol, 1,6-hexanediol, 1,8-octanediol, neopentyl glycol,
cyclohexane dimethanol (1,4-bis-hydroxy methyl cyclohex-
ane), 2-methyl 1,3-propane diol, glycerol, trimethylol pro-
pane, 1,2,6-hexane triol, 1,2,4~butane triol, trimethylol
ethane, pentaerythritol, quinitol, mannitol, sorbitol,
methyl glycoside, diethylene glycol, triethylene glycol,
tetraethylene glycol, polyethylene glycol, dipropylene
glycol, polypropylene glycols, dibutylene glycol, and
polybutylene glycols. The polyesters may contain some
terminal carboxyl groups. It is also possible to use
polyesters of lactones such as ~-caprolactone, or hydroxy
carboxylic acids such as l~hydroxy caproic acid.
The polythioethers that can be used include
the condensation products of thiodiglycol alone or thio-
diglycol with other glycols, dicarboxylic acids, formal-
dehyde, amino carboxylic acids or amino alcohols. The
products can be characterized as polythio mixed ethers,
polythioether esters or polythioether es-ter amides,
depending upon the components used.
Examples of suitable polyacetals include the
compounds obtained from glycols, such as diethylene gly-
col, triethylene glycol, 4,4'-dioxethoxydiphenyl dimethyl
methane, and hexanediol, and formaldehyde. Polyacetals
suitable for use in accordance with the invention can
also be obtained by polymerizing cyclic acetals~
28,037-F -5-
~6-
Suikable polycarbonates containing hydroxyl
groups are those of the type which are generally known
and which may be obtained by reacting diols, such as
1,3-propanediol, 1,4-butanediol and/or 1,6-hexanediol,
diethylene glycol, triethylene glycol or tetraethylene
glycol, with diaryl carbonates (for example, diphenyl
carbonate) or phosgene.
The polyester amidPs and polyamides suitable
for use herein include the predominantly linear conden-
sates obtained from polyvalent saturated and unsaturatedcarboxylic acids or their anhydrides, and polyvalent
saturated and unsaturated amino alcohols, diamines, poly-
amines and mixtures thereof.
Polyhydroxyl compounds already containing
urethane or urea groups and modified natural polyols,
such as castor oil, carbohydrates or starch, may also
be used. Addition products of alkylene oxides with
phenol-formaldehyde resins or even with urea-formalde-
hyde resins may also be used in accordance with the
invention.
Examples o the many and varied t~pes of com-
pounds suitable for use in accordance with the invention
are described in "High Polymers", Vol. XVI; "Polyure-
thanPsr Chemistry and Technology", by Saunders-Frisch,
Interscience Publishers, New York, London, Vol~ I, 1962,
pages 32 to 42 and pages 44 to 54, and Vol. II, 1964,
pages 5 to 6 and 198 to 199, and also in Kunststoff-
-~andbuch, Vol. VII, Vieweg-Hochtlen, Carl-Hanser-Verlag,
Munlch, 1966, pages 45 to 71.
28,037-F -6-
-- 7 -
Essentially any o~ganic polyisoc~anate m~
be used herein. Thus, it is possible i.n ~ccor~ance with
the inventlon ~o utilize aralipha~ic, aromatic and heter~
cyclic pOlyisocyânates. Specific examples of useful iso-
cyanates include, 1,3- and 1,4-phenylene diisocyanate,
1,4- and 3,6-tolylene diisocyanate and mixutes of these
isomers; diphenyl methane-2,4'- and/or 4,4'-diisocyanate;
naphthylene-1,5-diisocyanate; triphenylmethane-4,4',4"-
-triisocyanate; polyphenyl polymethylene polyisocyanates
which may be obtained by condensing anilin~ with formalde-
hyde, followed by phosgenation and which a.re of the type
~escribed, for example, in British Patents 874,430 and
848,671, perchlorinated aryl polyisocyanates of the type
described in German Patent 1,092,007; the diisocyanates
described in U.S. Patent 2,492,330; polyisocyanates con-
taining allophanate groups of the type described, for exam-
ply, in British Patent 994,890 and Belgian Patent 761,626;
polyisocyanates containing isocyanate groups of the type
described, for example, in German Patents 1,022,789; 1,222,067
and 1,027,394 and in German Offenlegungsschrifts 1,929,034
and 2,004,048, both published December 10, 1970; polyisocyanate.s
containing urethane groups as described in U.S. Patent 3,394,164;
the polyisocy~nates containing acylated urea groups described
in German Patent 1,230,778; polyisocyanates containiny
biuretgro~p-s of the type described, for example, in German
Patent 1,101,394i in British Pabent 880,050 and in French
Patent 70-17514i polyisocyanates obtained by telomerization
reactions as described in Belgian Patent 723,640; polyiso-
cyanates containing ester groups of the type described, for
example, in British Patents 956,474 and 1,072,956; in U.S.
Patent 3,567,763 and in German Patent 1,232,688; and reaction
products of the above-mentioned isocyanates with acetals as
described in German Patent 1,072,385.
28,037-F - 7 -
~8-
It is also possible to use the distillation
residues containing isocyanate groups which accumulate
ln the indu~trlal-scale production of isocyanates, option-
ally in solution in one or more of the above~mentioned
polyisocyanates. It is also possible to use mix~ures of
the above-mentioned polyisocyanates.
In general, it is particularly preferred to
use readily availa~le polyisocyanates, such as 2,4- and
2,6-tolylene diisocyanate and mixtures of these isomers
(TDI), polyphenylpolym~thylene polyisocyanates of the type
obtained by condensing aniline with formaldehyde, followed
by phosgenation (crude MDI); and polyisocyanates contain-
ing carbodiimide groups, urethane groups, allophanate
groups, isocyanurate groups, urea groups or biuret groups
(modified polyisocyanates).
Blowing agents suitable for use in combination
with the methylene chloride in accordance with the instant
invention include water and/or readily volatile organic
substances. Examples of organic blowing agents include
acetone; ethyl acetate; halogen-substituted alkanes such
as chloroform, ethylene chloride, vinylidene chloride,
monofluorotrichloromethane, chlorodi~luoromethane and
dichlorodifluoromethane, butane, hexane, heptane and
diethylethers.
Additionally, catalysts are often used in
the process of the instant invention. Suitable catalysts
include tertiary amines such as triethylamine, tributyl-
amine, N-methyl morpholine, N-ethyl morpholine, N-cocomor-
pholine, N,N,N',N'-tetramethyl ethylenediamine, 1,4 diaza-
bicyclo-(2,2,2)-octane, N-methyl-N'~dimethyl aminoethyl
28,037-F w8-
piperazine, N,N~dimethyl benzylamine, bis-~N,N-diethyl
aminoethyl)-adipate, N,N-diethyl benzylamine, pentamethyl
diethylenetriamine, N,N-dime-thyl cyclohexylamine, N,N,N',N'-
-tetramethyl-1,3-~utanediamine, N,N-dimethyl.-~-phenylethyl-
amine, 1,2-dimethyl imidazole and 2-methyl imidazole.
Suitable metal catalysts include metal che-
lates, bicyclic amidines and monocyclic amidines, either
alone or especially in combination with monocarboxylic
or dicarboxylic acids, with metal octoates being preferred.
Suitable bicyclic amidines include compounds
corresponding to the general formula
~(CH2)n\
~N C ~ N
~ (C~2)m ~
in which m = 2 or 3 and n - 3, 4 or 5.
EY.amples o~ monocyclic amidines i.nclude com-
pound5 corresponding to the general ormula
C
R-N / ~ N
CH3
28,037-F -9
-10--
in which R is an optionally branched and/or heteroatom-
-containing aliphatic, cycloaliphatic, araliphatic or aro-
matic radical havin~ 1 to 15 carbon atoms. R may thus be,
for example, methyl, cyclohexyl, 2-ethylhexyl, benzyl,
cyclohexylmethyl, ethoxyl or a radical corresponding to
the fonmula
CH3
CH3-CH3-N / ~ N
CH3 / CH3
CH3
In addition, other catalysts may also be used
in the process according to the invention. Examples of
these catalysts and information about the manner in which
they perform may be found in Kunststoff-Handbuch, Vol. III,
Vieweg and Hochtlen, Carl-Hanser-Verlag, Munich 1966, pages
96 to 102.
It is advantageous, although not essential, to
use surface-active additi.ves such as emulsifiers and o~lm
stabilizers of the type commonly used in the producti.on
of foamed polyurethanes, in the process according to the
inven~ion. Silicone-containing skabilizers are particu-
larly desirable where the reactive mixture is prefoamed
by "whipping in" air and "whip-foaming" before or during
the chemical reaction.
Polyols containing fillers may also be used
for the process according to the invention. Examples
of suitable fillers include naturally occurring minerals
28,037-F -10-
~3~
such as chalk, kaolin or baryta in finely divided fo~n,
aluminum oxide hydrates, mixtures thereof and mixtures
with other fillers and/or flameproofing additives.
The reaction components may be generally
reacted in known manner by the one-stage process, by
the prepolymer process or even by ~he semi~prepolymer
process, advantageously using machinery of the kind
described, for example in Kunststoff-Handbuch, Vol. VII,
Vieweg-Hochtlen, Carl-~anser-Verlag, Munich 1966, on
pages 121 to 205.
The following examples illustrate that very
soft polyurethane foams can be prepared using smaller
amounts of the metal catalyst when methylene chloride
is employed as the principle auxiliary blowing agènt,
together with the low molecular weight polyhydroxy com-
pounds in accordance with the present invention, than
previously employed when the low molecular weight poly-
hydroxy compound of the present invention was omitted.
Further, the amount of catalyst employed when a polyure-
thane foam is prepared in accordance with the presentinvention is nearly that which one would expect to employ
when using the fluorocarbons of the present day art.
In order to obtain a fair comparison of prop-
erties the comparative examples have been run on similar
laboratory foam apparatus to produce slabs 3 feet by
30 feet (0.91 m by 9.1 m). While the properties are
not the same as those obtained on commercial scale con-
tinuous apparatus, the laboratory scale apparatus pro
duces foams which are consistently comparable, although
having slightly poorer characteristics than the commer-
cial scale equipment-produced foams.
28,037-F
-12-
The following table sets forkh the results
obtained employing laboratory equipment. The data illus-
trate that the addition of glycerine to a foam formula-
tion in which methylene chloride i5 to be used as a blow-
ing agent to produce very soft foams reduces the amountof metal catalyst, such as stannous octoate, required to
produce substantially equivalent foams. Comparative Runs
1 to 4 illustrate the characteristics obtained in the
laboratory equipment producing foams 3 feet by 30 feet
(0.91 m by 9.1 m) when using methylene chloride and no
glycerine as is co~mon practice in the industry today.
The amounts of metal catalyst are 150 to 175 percent
greater than that metal catalyst commonly used by the
industry when fluorotrichloromethane is used as the
blowing agent rather than methylene chloride (see Com-
parative Runs 5 and 6). Runs 1 to 6 illustrate the inven-
tion and show the marked reduction in metal catalyst
required to obtain oams of equivalent properties when
0.5 part of glycerine is used per 100 parts of polyol.
In Compara-tive Runs 2 to 4 the TDI Index and isomer ratio
and amoun-ts of polyol, water, fluoro-trichloromethane,
methylene chloride, silicone surfactant and amlne cata-
lyst were the same as in Comparative Run 1. I~ Run 2 of
the present invention the data for the first e.ight com-
ponents listed in the table are the same as for Run 1,and in Runs 5 and 6 the data for the same eight compo-
nents are the same as for Run 4.
28,037-F
-13-
O Ln In ~ ~ C~ ~ O ~ O ~ O O O O ~ ~
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H
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C O r~l O U') ~ O 11') N u~ 1) ~ O O ~ 117 0 0 0 U~ O ~)
U~ ~1 .... ~............ .....
O a) ~o O ~ O ~`1 ~1 O O O O IJ- ~ O ~ ~ O ~--t` ~ ~ d; ~ r-~
h O d~ O ~ N ~1
1:4 ~ 'I _ 1
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O ~ O In D O r~ N ~1
~n In U7--
H ~:: tr~ ~ ~ N ~ d~ O O O O O O ~ 1 0
1~ p:~ o o o It~ ~o o
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o o o o u~ ~o o Lr) a ,I d~ D ~ ,l ~o
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a~ ~o o ~ o ~ ,~ o o o o u~ ~o o ~ c~ ,~ o g co ,I Ln ~ ,i
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2 8 , 0 3 7-F - 13-
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Lr~ ~ o ~ ~n o ~ o o o ,~ ~o ~ o d~ co ~ ~ ~ ~ o ~ D
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~ O O O ~ O ~ ~ o cn o o o ~ o o o a) ~o ~ Ln
O o a: o ~ ~ o ~1 o o o o In O O Ll~ O ~ ~ r- o ~ o ~
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d~ 0 N t` ~0 O O O U) O O O r-l ~ O
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O O ~1 ~ ~ O C~ ~1 ~I d1 ~O Ct:) N ~ d~ N
r~ ~ N 10 ~ rl N r-l
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rl ~n Ln ~ d1 ~ d~ O O 0 ~4 CO ~ ~
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,,,,~,.~.............................. ~
O ~ O ~ ~ O O O ~ ~ ~D O ~ O O ~ ~O O
1~1 O ~ O C~ N ~ tl u~ . ~1 ~ ~1
Ln ^ N
t~ ~ _
o ,~ o Ln ~ o Ln ~ ~ Ln cr~ 1 o o c~ ~ o o o u~
ao0o~ o~,~ ooooLn ~oo ~o~oLn~ c~Ln~
O d~ O 1:~ N ~ LO ~ rl ~`I r~~
r~l
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n Ln ~n
,~,, ~ ~1 ~ O O ~ ~ N ~0 N
,~ o o h ~ ~ ~ rl ~ a~ s~
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Q ~ o ~ o ~ a) a) a
28, 037-F -14-
-15- ,
o
U
~1
~ ~o
O ~ ,~
U~
0 h 0
O ~
~ a) 0
$ ~X ~n
0 ~ O
O ~ 4
0 0
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h ~
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a) ~ rl a
O
V G~
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O O rl ~ ~ O
0 o 11
s.~
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~; ~I h t~ ~ o ,1
X a~ O ,f} ~t~
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O ~ U
O ~ h _ \ ~ ~ r~
~ u ~ ~ tn tJ u a) o
ra O
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O h O h ~ ~l 4
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O ^ ~rd .,IJ ~1
M 3 ~ O a) a ~ ~ ~ M
11~ td O ~ ~ rl r, ,a o o
~` ~ r~l ~ ~ ~r q.~ o 5:: E-
~ C U X 4~ rl
u ,u o ,a o . ~1_~
rl ~ ~ ~ o ~t ~ 4~i E~
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r, o ,~ \ ~ I
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O ~ ~ ~ r~ ~ ~ , ~
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O r~ O ~J 1;~
u a
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U~ Ul ~ rn ~ ~ ,1 U
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E~ ~ r~ ~1 ~ a
E~ E~ 3 E I ~ o u~ Q E~ ~ H lCt
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1:4 ~I N ~ 0 t.~ CO
28,037-F - 15-
Example II illustrates runs in ~hich a fluoro-
carbon was employed as the blowing agent with and without
the polyhydroxy compound, showing that smaller amounts of
gelation catalyst can be used with a fluorocarbon and
glycerine (Run 7) and no glycerine (Comparative Run 7).
Su~stantially equivalent foams were obtained.
Exam~le II
Compara-
tlve
10 Formula~ion Run 7 Run 7
Polyol 3010 100.0 100.0
TDI Index 108.0 108.0
TDI 46.4 48.0
H2O 3.5 3.5
Fluorotrichloromethane 23.0 23.0
Silicone surfactant 1.5 1.5
Two amine catalysts 0 22 0 22
Stannous Octoate 0.37 0.2
20 Glycerine - 0.5
Example III
In this example another polyol - an adduct o~
propylene oxide (PO) and glycerine - which ls soluble
in methylene chloride was used in place of the ~lycerine
of the previous examples. The adduct contained 1.6 moles
of PO per mole of glycerine. Again, foams of comparable
28,037-F -16-
-17~
properties were produced while employing less metal cata-
lyst when the glycerine-PO adduc-t was employed according
to the invention. Comparative Run 8 contains no adduct
and Runs 8 to 10 were performed in accordance with the
invention (all components in Runs 8 to 10 are the same
as in Comparative Run 8 except where noted).
Com-
para-
tive
Formulation Run 8 Run 8 Run 9Run 10
Polyol 3010 100.0
TDI Index 108.0
TDI 46.4 47.2 47.046.9
H2O 3.5
MeCl2 22.0
Silicone
Surfactant 1.50
Amine 0.17
Catalysts 0.08
Stannous Octoate 0.575 0.50 0.45 0.50
Adduct none 0.50 0.400.30
28,037-F -17-
