Note: Descriptions are shown in the official language in which they were submitted.
1 336023
Mo3122
PU-322
ISOCYANATE REACTIVE MIXTURE AND THE USE THEREOF
IN THE MANUFACTURE OF F~EXIBLE POLYURETHANE FOAMS
BACKGROUND OF THE INVENTION
It is known in the art to manufacture flexible
polyurethane foams using mixtures of methylene
bis(phenyl isocyanate) ("MDI") and polymethylene
poly(phenyl isocyanate) ("polymeric MDI") and
prepolymers based on such mixtures. See, e.g.,
U.S. Patents 4,239,856, 4,256,849, 4,261,852, and
4,365,025. Typical isocyanate reactive materials
suggested for use with such isocyanates include
i) mixtures of polyether triols having molecular weights
of from 2000 to 7000 with diethanolamine
(U.S. 4,239,856); ii) mixtures of 400 to 10,000
molecular weight polyethers having primary hydroxyl
groups with low molecular weight active hydrogen
containing materials (U.S. 4,256,849); iii) polyoxy-
propylene or poly(oxypropylene-oxyethylene) diols or
triols having equivalent weights of from 700 to 2000
(U.S. 4,261,852) and iv) water (U.S. 4,365,025).
It is also known to use various low molecular
weight crosslinkers in the manufacture of flexible
foams. U.S. Patent 3,067,148 describes the use of
tetrahydric compounds derived from ethylene diamine and
alkylene oxides. U.S. Patent 3,948,825 describes the
use of reaction products of methylene dianiline and
alkylene oxides. U.S. Patent 4,569,952 describes the
use of an addition product of an alkylene oxide and an
aromatic diamine and a mixture of the addition product
with an alkanolamine.
Finally, Dupont has recently introduced an
amine sold as Dytek*amine for a ~Tariety of uses. The
Dytek*amine is described as 2-methylpentamethylene-
~trade-mark
Mo3122
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~`
A
1 336023
diamine. Among the uses suggested in product bulletin
entitled "Amines" is the use as a chain extender for
polyurethanes.
While many foam formulations based on MDI and
polymeric MDI give adequate properties for many
applications, it is generally difficult to have good
processability over a broad isocyanate index range.
Additionally, it would be desirable to develop a foam
having high tear strength, high elongation, and low
compression set for automotive seating and headrests and
for nonautomotive seating.
DESCRIPTION OF THE INVENTION
The present invention is directed to a reactive
mixture for use in producing flexible polyurethane
foams. The reactive mixture gives good processability
over a broad isocyanate index range. Foams of a wide
range of densities can be produced with good mold vent
stability over a wide isocyanate index range. The flow
times of the foam systems are extended, which, when
combined with the improved vent stability, gives much
improved molded parts. The foams produced from the
reaction mixtures have improved green strength upon
demold with reduced, and, in most cases, eliminated
finger printing. In addition, the use of cell-openers
is not required. Finally, when using the preferred
formulations, the foams produced have high tear
strengths, high elongations, and low compression sets.
More particularly, the isocyanate reactive
mixtures of the present invention comprise:
A) from more than 0 up to 3 parts by weight
per 100 parts by weight of components B)
and C) of an amine of the formula:
H2N - R - NH2
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where R is a C3 to C10 straight or branched alkylene
group or a C4 to C15 alicyclic group,
B) from 0 to 30% by weight of a polyoxy-
alkylene polyamine having a molecular
weight of from about 400 to about 5000 and
containing from 2 to 3 primary amino
groups, and
C) from 70 to 100% by weight of one or more
polyether polyhydroxyl compounds having
hydroxyl functionalities of from 2 to 3 and
molecular weights of from about 1000 to
about 10,000, the percents by weight of
component B) and component C) totalling
100%.
Component A) is preferably used in an amount of
from 0.05 to 2.5 parts by weight and most preferably in
an amount of from 0.25 to 1.5 parts by weight.
Component B) is preferably used in an amount of from 1
to 20% by weight and most preferably from 2.5 to 15% by
weight, with component C) preferably used in an amount
of from 80 to 99% by weight and most preferably from 85
to 97.5% by weight. The preferred and most preferred
ranges produce foams of the best overall physical
properties. The foams of the present invention are
prepared by reacting the above reaction mixture with a
polymethylene poly(phenyl isocyanate) containing from
about 40 to about 85% by weight of methylene bis(phenyl
isocyanate) or a prepolymer of such isocyanate, with
such prepolymer having an isocyanate content of from
about 15 to about 30% by weight. The isocyanates useful
herein are generally known and are produced by reacting
phosgene with aniline/formaldehyde condensates. Known
processes for preparing the aniline/formaldehyde
condensates and the resultant polyisocyanates are
described in the literature and in many patents, for
Mo3122
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~ 3 ~
example, U.S. 2,683,730, 2,950,263, 3,012,008, 3,344,162
and 3,362,979. Additionally useful isocyanates are
described in U.S. 4,256,849. Useful prepolymers are
described in U.S. 4,261,852. In general the isocyanate
index is from 60 to 140, and is preferably from 90 to
120.
Component A) of the reaction mixture of the
present invention is an amine of the formula:
H2N -R- NH2
where R is a C3 to C10 straight or branched chain
alkylene group or a C4 to C15 alicyclic group. Useful
diamines include the various straight and branched chain
isomers of diaminopropane, diaminobutane, diaminopentane,
diaminohexane, diaminoheptane, diaminooctane,
diaminononane, and diaminodecane. Specific useful
diamines include 1,2- and 1,3-diaminopropane; 1,3-, 2,3-,
and 1,4-diaminobutane; 1,2-diamino-2-methylpropane;
1,5-diaminopentane; 1,4-diamino-1-methylbutane;
1,4-diamino-2-methylbutane; 1,3-diamino-1-ethylpropane;
1,3-diamino-1,1-dimethylpropane; 1,3-diamino-1,2-di-
methylpropane; 1,3-diamino-2,2-dimethylpropane;
1,5-diamino-2-methylpentane; 1,6-diaminohexane
and the like. Useful alicyclic diamines include the
various isomers of diaminocyclobutane, diamino-
cyclopentane, diaminocyclohexane, diaminocycloheptane,
diaminocyclooctane, and diaminocyclononane. Also
useful are the diamino-1-methylcyclohexanes; the
methylenebis(cyclo-hexylamines); the diamino-1-
methylcyclopentanes; the diaminodimethyl-cyclo-
hexanes; isophorone diamine; and the like. It is
presently preferred to use those diamines where R is a
branched chain alkylene group. The most preferred
material is 1,5-diamino-2-methylpentane.
Mo-3122 - 4 -
, , ,,~
1 3~6023
Component B) of the reaction mixture is a
polyoxyalkylene polyamine having a molecular weight of
from about 400 to about 5000, and having from 2 to 3
primary amine groups. Such polyamines are known in the
art. One method for preparing such amines is the
amination of polyhydroxy polyethers (e.g.,polypropylene
glycols) by a reaction with ammonia in the presence of
Raney nickel and hydrogen (Belgian Patent 634,741).
U.S. 3,654,370 discloses the preparation of polyoxy-
alkylene polyamines by reaction of the correspondingpolyol with ammonia and hydrogen in the presence of a
nickel, copper, or chromium catalyst. The preparation
of polyethers containing amino end groups by the
hydrogenation of cyanoethylated polyoxypropylene ethers
is described in German Patent 1,193,671. Other methods
for the preparation of polyoxyalkylene polyamines are
described in U.S. Patents 3,155,728 and 3,236,895 and
French Patent 1,551,605. Commercially available
polyether poly~mines are sold by Texaco under the
Jeffamine t ra d e-ma r k .
Component C) comprises one or more polyether
polyhydroxyl compounds having hydroxyl functionalities
of from 2 to 3, and having molecular weights of from
about 1000 to about 10,000, and preferably from about
2000 to about 6000. Such polyethers are generally known
in the art. These polyethers may be obtained by
polymerizing epoxides, such as ethylene oxide, propylene
oxide, butylene oxide, tetrahydrofuran, styrene oxide or
epichlorohydrin in the presence of Lewis catalysts such
as BF3. Polymerization may also be accomplished by the
addition of epoxides (preferably ethylene and/or
propylene oxide) either in admixture or successively, to
compounds containing reactive hydrogen atoms such as
water or alcohols. Examples of suitable reactive
compounds include ethylene glycol, 1,3- and
Mo3122
1 336023
1,2-propylene glycol, trimethylol propane, glycerol and
the like. Also useful are the polyethers containing
high molecular weight polyadducts and polycondensates or
polymers in finely dispersed or dissolved form. Such
5 polyethers may be obtained by polyaddition reactions
(for example, reactions between polyisocyanates and
aminofunctional compounds) and polycondensation
reactions (for example, between formaldehyde and phenols
and/or amines) in situ in the above described
10 polyethers. Such processes are described in German
Auslegeschriften 1,168,075 and 1,260,142 and in German
Offenlegungsschriften 2,324,134, 2,423,984, 2,512,385,
2,513,815, 2,550,796, 2,550,797, 2,550,833, 2,550,862,
2,633,293, and 2,639,254. See also U.S. Patents
15 3,325,421, 4,042,537, 4,089,835, 4,293,470, 4,296,213,
and 4,374,209. Also useful are the so-called polymer
polyols obtained by polymerizing one or more
ethylenically unsaturated monomers in a polyether. Such
polymer polyols are described in U.S. 3,383,351,
20 3,304,273, 3,523,093, 3,110,685 and RE 28,715 and
29,118. Polymer polyols are commercially available from
Bayer AG, BASF, and Union Carbide. Regardless of the
specific polyether used herein, it is generally
preferred to use polyethers containing primary hydroxyl
25 groups.
According to the invention, water and/or
readily volatile organic substances are used as blowing
agents. Suitable organic blowing agents include, for
example, acetone, ethyl acetate and halogen substituted
30 alkanes such as methylene chloride, chloroform,
ethylidene chloride, vinylidene chloride, monofluoro-
trichloromethane, chlorodifluoromethane, and
dichlorodifluoromethane as well as butane, hexane,
heptane and diethyl ether. The effect of a blowing
35 agent can also be obtained by the addition of compounds
Mo3122
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which decompose at temperatures above room temperature
to release gases such as nitrogen, e.g., azo compounds
such as azoisobutyric acid nitrile. Further examples of
blowing agents and the use of blowing agents are known
and have been described, e.g., in Kunststoff-Handbuch,
Volume VII, published by Vieweg and Hochtlen,
Carl-Hanser-Verlag, Munich 1966, e.g., on pages 108 and
109, 432 to 455 and 507 to 510.
Catalysts are also frequently used according to
the invention. The catalysts added are generally known
and include tertiary amines such as triethylamine, tri-
butylamine, N-methylmorpholine, N-ethylmorpholine,
N-cocomorpholine, N,N,N' ,N"-tetramethyl-ethylene-
diamine, 1,4-diaæa-bicyclo-(2,2,2)-octane, N-methyl-N'-
dimethyl-aminoethylpiperazine, N,N-dimethylbenzylamine,
bis-(N,N-diethyl-aminoethyl)-adipate, N,N-diethylbenzyl-
amine, pentamethyl-diethylenetriamine, N,N-dimethyl-
cyclohexylamine, N,N,N',N'-tetramethyl-
1,3-butanediamine, N,N-dimethyl-~-phenylethylamine,
1,2-dimethylimidazole, 2-methylimidazole and the like.
Also useful are the commercially available tertiary
amines such as Nia~`Al and Niax* A107, available from
Union Carbide; Thancat*DD, available from Texaco; and
the like. Mannich bases known per se obtained from
secondary amines such as dimethylamine and aldehydes,
preferably formaldehyde, or ketones such as acetone,
methyl ethyl ketone or cyclohexanone and phenols such as
phenol nonylphenol or bisphenol may also be used as
catalysts. Examples of catalysts which consist of
tertiary amines having hydrogen atoms which are reactive
with isocyanate groups include triethanolamine,
triisopropanolamine, N-methyl-diethanolamine,
N-ethyl-diethanolamine, N,N-dimethyl-ethanolamine and
their reaction products with alkylene oxides such as
propylene oxide and/or ethylene oxide.
trade-mark
Mo3122
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~5
- 1 336~2~
Silaamines having carbon-silicon bonds as
described, e.g., in German Patent No. 1,229,290 and
U.S. Patent No. 3,620,984 may also be used as catalysts.
Examples include 2,2,4-trimethyl-2-silamorpholine and
1,3-diethylaminoethyltetramethyldisoloxane.
Basic nitrogen compounds such as tetraalkyl-
ammonium hydroxides, alkali metal hydroxides such as
sodium phenolate and alkali metal alcoholates such as
sodium methylate may also be used as catalysts. Hexa-
hydrotriazines are also suitable catalysts.
Organic metal compounds may also be used ascatalysts according to the invention, in particular
organic tin compounds. The organic tin compounds used
are preferably tin(II) salts of carboxylic acids such as
tin(II) acetate, tin(II) octoate, tin(II) ethyl hexoate
and tin(II) laurate and tin(IV) compounds such as
dibutyl tin oxide, dibutyl tin dichloride, dibutyl tin
diacetate, dibutyl tin dilaurate, dibutyl tin maleate or
dioctyl tin diacetate. All the above-mentioned
catalysts may, of course, be used as mixtures.
Further examples of catalysts which may be used
according to the invention and details concerning the
activity of the catalysts are known and are described,
e.g., in Kunststoff-Handbuch, Volume VII, published by
Vieweg and Hochtlen, Carl-Hanser-Verlag, Munich 1966,
pages 96 to 102.
The catalysts, when used, are generally used in
a quantity of between about 0.001 and 10%, by weight,
based on the quantity of primary hydroxyl group
containing polyethers.
Surface active additives such as emulsifiers
and foam stabilizers may also be used according to the
invention. Suitable emulsifiers include, e.g., the
sodium salts of ricinoleic suLphonates or salts of fatty
acids with amines such as oleic acid diethylamine or
Mo3122
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1 336023
stearic acid diethanolamine. Alkali metal or ammonium
salts of sulphonic acids such as dodecylbenzene
sulphonic acid or dinaphthylmethane disulphonic acid or
of fatty acids such as ricinoleic acid or of polymeric
fatty acids may also be used as surface active
additives.
Polyether siloxanes are particularly suitable
foam stabilizers, especially useful are those which are
water soluble. These compounds generally have a
polydimethyl siloxane group attached to a copolymer of
ethylene oxide and propylene oxide. Foam stabilizers of
this kind are known and have been described, for
example, in U.S. Patent Nos. 2,834,748, 2,917,480 and
3,629,308. It may, however, be advantageous to carry
out the process according to the invention without foam
stabilizers.
Other additives which may also be used
according to the invention include reaction retarders,
e.g., substances which are acid in reaction such as
hydrochloric acid or organic acid halides, cell
regulators such as paraffins or fatty alcohols or
dimethyl polysiloxanes, pigments, dyes, flame retarding
agents such as tris-chloroethyl phosphate, tricresyl
phosphate or ammonium phosphate and polyphosphates,
stabilizers against ageing and weathering, plasticizers,
fungistatic and bacteriostatic substances, and fillers
such as barium sulphate, kieselguhr, carbon black or
whiting.
Other examples of surface active additives,
foam stabilizers, cell regulators, reaction retarders,
stabilizers, flame retarding substances, plasticizers,
dyes, fillers, and fungistatic and bacteriostatic
substances which may be used according to the invention
and details concerning the use and mode of these
additives are known and may be found, e.g., in
Mo3122
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1 336023
Kunststoff-Handbuch, Volume VII, published by Vieweg and
Hochtlen, Carl-Hanser-Verlag, Munich 1966, on pages 103
to 113.
According to the invention, the components may
be reacted together by known processes often using
mechanical devices such as those described in
U.S. Patent No. 2,764,565. Details concerning
processing apparatus which may be used according to the
invention may be found in Kunststoff-Handbuch, Volume
VII, published by Vieweg and Hochtlen, Carl-Hanser-
Verlag, Munich, 1966, pages 121 and 205.
According to the invention, the foaming
reaction for producing foam products is often carried
out inside molds. In this process, the foamable
reaction mixture is introduced into a mold which may be
made of a metal such as aluminum or a plastics material
such as an epoxide resin. The reaction mixture foams up
inside the mold to produce the shaped product. The
process of foaming in molds is carried out to produce a
product having a cellular structure on its surface.
According to the invention, the desired result can be
obtained by introducing just sufficient foamable
reaction mixture to fill the mold with foam after the
reaction is completed.
So-called external mold release agents known in
the art, such as silicone waxes and oils, are frequently
used when foaming is carried out inside the molds. The
process may also be carried out with the aid of
so-called internal mold release agents, if desired, in
combination with external mold release agents, e.g.,
described in German Offenlegungsschriften Nos. 2,121,670
and 2,307,589.
Cold setting foams may also be produced, as
described in British Patent No. 1,162,517 and German
Offenlegungsschrift No. 2,153,086.
Mo3122
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1 336023
Foams may, of course, also be produced by the
process of block foaming or by the laminator process
known in the art. The products obtainable according to
the invention may be used, for example, as upholstery or
padding materials.
The invention is further illustrated but is not
intended to be limited by the following examples in
which all parts and percentages are by weight unless
otherwise specified.
EXAMPLES
In the examples which follow, the following
materials were used:
A) POLYOL A: a glycerin initiated-propylene
oxide/ethylene oxide polyether (weight ratio of
PO to EO of about 5:1) having a molecular weight
of about 6000.
B) POLYOL B: a propylene glycol initiated-propylene
oxide/ethylene oxide polyether (weight ratio of
PO to EO of about 7:1) having a molecular weight
of about 4000.
C) POLYAMINE A: an approximately 400 molecular
weight difunctional primary amine terminated
polyether, available from Texaco as Jeffamine`
D-400.
D) POLYAMINE B: Jeffamine D2000, a 2000 molecular
weight polypropylene oxide diamine, available
from Texaco.
E) DYTEK A: 2-methylpentamethylenediamine,
available from Dupont.
F) SILOXANE A: B8002, a siloxane available from
Goldschmidt.
G) SILOXANE B: KS 43, a low molecular weight
polyoxyalkylene polysiloxane available from
Bayer AG.
*trade-mark
Mo3122
1 336~23
-- H) CELL OPENER A: a glycerin based ethylene
oxide/propylene oxide polyether having an OH
number of about 35.
I) CELL OPENER B: a sorbitol initiated-propylene
oxide/ethylene oxide polyether (weight ratio of
PO to ~O of about 5:1) having an OH number of
100 .
J) WATER
K) ISOCYANATE: Mondur MRS-2, available from ~iles Inc.
a polymethylenepoly(phenyl isocyanate)
containing 78% by weight diisocyanate, having an
isocyanate content of about 33Z, an equivalent
weight of about 127, and a viscosity of about
22 cps at 25C.
In the examples, the components of the B-side
were accurately weighed into a suitable container and
mixed using an air driven two blade mixer. The
resultant mixture was then taken to the metering
equipment. The metering equipment was flushed with the
mixture and calibrated for the desired foam index.
The mixture was mixed with the isocyanate using
high pressure metering equipment (HENNECKE HK100) and a
Hennecke MQ-12-2 self-cleaning mixhead. Process
settings were as follows:
TEMPERATURE MIX/ISO: 80/80F
MIX PRESSURES MIX/ISO 2500/1600 psi
MOLD TEMPF 130-150
MOLD RELEASE Brulin 2023
DEMOLD TIME 3-5 minutes
The reaction mixture was metered into a
15 inch x 15 inch x 4 inch mold (which had been
previously sprayed with the mold release), in an amount
sufficient to give the desired foam density. The mold
was then closed and the foam part demolded after the
reaction was complete. The parts were labelled and
~trade-mark
Mo3122
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1 336023
tested for physical properties. The parts were aged
under standard ASTM conditions (50% RH, 72-74F) for
three days. The parts were then tested under ASTM 2406
laboratory procedures as specified in Chrysler MS-DC634.
The formulations used and the results obtained
were as reported in the following table (all amounts are
in parts by weight):
Mo3122
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n n
n
n ~ ~
I~ o o I o ~ I ,1 I J I I I o
n
Ln n ~
`D OOIOI~1 1 ~III I o
n n ~
oololl I ~ 1lll o
n
n n ~
on~n~l 1 ~lll l o
~n n
n n n n
~n
no~
~1 C') I ~11 1 '~ I ~ I I I I O
no~
~1 ~ o I ,~I I ~1 1 o ~ o I I I I ~
no~
o o o I ,~ I o ~ o I I I 1 00
no~
~ ~ ~D I ,~ 1 1 0 ~7 0 1 ~ I I ~
n no ~
oo o o I I I I o I o ~ I I I I o
nn n
n no ~
l-- o o I I I I o I o ~i I I I I o
nn n
n no
~n~nlllllo~
n
n no
n ~nnlllllo~
n
n o ~ o~
~ o o o I ~ I I o I ~ o I I I I o
nn
n
~n o ~ o~
~nLn ~ 10l~0llll
~n o ~ o~
nl~lll~llll o
Ln o C~ O 1~
nl~lll~llll ~o
~n
~n ~
z ~ z ~ ¢ ~ ~
o o '' ~ ~ ? ? ? ? -~. a
3 ~ ~ o
--14--
TABLE (Cont'd~
EXAMPLE 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
RESULTS:
Density (kg/m )49 44 43 46 42 44 42 42 45 42 41 43 42.3 43.1 41.3 46.4 36.8 43.7
Tensile (kPa) 136 131 141 186 97 145 154 197 118 137 170 200 155 154 155 143 173 146
Elongation (~)170 134 134 114 157 153 136 145 159 148 144 137 153 144 160 156 134 156
Tear Strength (N/m) 189 215 228 236 184 201 227 315 263 271 368 438 245 259 264 259 315 245
COMPRESSION SET (%)
(based on original
deflection)
2A 50 71.8 22.1 22.2 21.111.9 10.8 11.213.9 20 14.8 13 21.4 16.4 21 16.4 16.8 28.4 19
2A 75 92.7 93.5 8977.1 56.6 8.8 10.4 12.8 64 23.511.8 12.0 14.4 25 12.8 18.2 20 25.4
2C 50 48.5 28.3 25.3 18.517.5 13.1 12.815.7 18 16.8 15.4 15.8 15.4 21.4 19.6 17.7 25.2 16.8
2C 75 87.4 85.8 69.7 17.212.8 11.3 11.214.2 16 14.4 15.0 14.2 16.5 20.2 14.1 13.3 23.4 14.9
* Al refers to Niax Al, a tertiary amine catalyst available from Union Carbide;
LV refers to Dabco 33LV, a tertiary amine catalyst available from Air Products; a
the numbers (e.g. 1/1, 1/1.5, etc.) refer to the weight ratio of A1 to LV.
2A is the original foam, while 2C is the foam humid aged to the Chrysler CS~
specification. 50 and 75 are the ~ deflections for the test.
`- 1 3 3 6 0 2 3
Examples 1 through 4 are comparative examples.
All the other examples had excellent processing
characteristics. As far as the compression set data, in
general values of less than 30% are desirable, with the
lower the % the better the value.
Although the invention has been described in
detail in the foregoing for the purpose of illustration,
it is to be understood that such detail is solely for
that purpose and that variations can be made therein by
those skilled in the art without departing from the
spirit and scope of the invention except as it may be
limited by the claims.
Mo3122
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