Note: Descriptions are shown in the official language in which they were submitted.
~ 4333 Mo-2346
I,e~ 20,842
SOLUTIONS OF OLIGO-URETHANE ETHERS IN
POLYETHER POLYOLS AND THEIR USE IN A PRO-
CESS FOR THE PRODUCTION OF POLYURETHANE FO~MS
B~CKGROUND OF THE INVENTION
This invention relates to solutions of separa-
- tely-prepared oligo-urethane ethers containing terminal
OH-groups in relatively high molecular weight poly-
ethers containing terminal hydroxyl groups and to the
use of these solutions as modified polyols in the pro-
duction of polyurethane foàms characterized by excellent
high-frequency weldability and flame-laminatability.
Applications where high-frequency weldability
is a particularly desirable property inc1ude, for
example, the production of door linings for motor
vehicles, in which sheets of foam have to be welded to
one another or to other materials; the manufacture of
articles with guilted surface appearances; or the
production of moldings. In addition, flame lamination
is used for the production of composite systems of
foams with textiles, such as in upholstery backings
which are subsequently profiled and/or formed by high-
frequency (e.g~ where the welding energy is provided
by an electromagnetic fieldl. (HF welding).
It is known that flame-laminatable and, to a
certain extent, high-frequency-weldable foams can be
produced from polyisocyanates and polyester polyols
using suitable auxiliaries and additives. However,
these foams can only be produced in special processing
machines and are inferior in many properties to poly-
ether-polyurethane foams. ~or example, their open-
cell structure is poorer, their elasticity lower and
their resistance to moisture and heat inferior.
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~.~
~8~
Flame-laminatable ahd high-fre~uency-wèldable
polyurethane foams can be produced fro~ polyether
polyols, polyisocyanates, water and/or blowing agents
in the presence of emulsifiers, stabili.zers, catalysts
and other auxiliaries, by the addition of special
auxiliaries.
Thus, US Patent No. 3,205,120 describes the
production of flame-laminatable polyether-polyurethane
foams by the addition of,a,relatively small quantity
of a polyol (particularly phosphorous-containing poly-
ols, such as tris-(dipropylene glycol)-phosphite~having
a molecular weight in the range from 20~ to 1500.
~isadvantages of this process include a deterioration
in processing reliability, a certain tendency towards
c~re ~ discoloration and a flame-lamination behavior
which is distinctly inferior to that of a polyester-
polyurethane foam because of the polyol quantities
normally used.
US Patent No. 4,060,439 describes the co-
foaming of small quantities of alkylene glycolscontaining from 2 to 8 carbon atoms, or triols con-
taining from 3 to 10 carbon atoms, dialkanolamines
containing from 2 to 10 carbon atoms with short-chain
glycol ethers and polyhydric phenols into flexible
polyether foam formulations. However, experience has
shown that the co-foaming of compounds such as these
makes foaming more difficult and, in particular, very
considerably narrows the processing gap between an
open-cell and a closed-cell structure.
In addition, US Patent No. 3,497,416 describes
the foaming of a polyether polyol with a modified
Le~ 20,842
333
polyisocyanate ~the reaction product of dipropylene
glycol and/or dibutylene glycol with an excess of poly-
isocyanate) for the production of a weldable poly~
urethane foam. The disadvantage of this process ]ies
in the fact that, to obtain sufficient open cells,
dimethyl formamide ~ a toxicologically-unacceptable
substance, has to be used as cell-opening agent. In
addition, foams of this type have a high compression
set, and polyether-NCO-p~epo~lymers o~ this type used
show only moderate stability in storage.
In view of the disadvantages of polyether-
polyurethane foams which account for the fact that,
~on the-whole,-polyester-polyurethane foams are used for
flame lamination and for high-frequency welding, there
is a considerable need for a flame-laminatable and
high-frequency (HF)-weldable polyether foam which
can be manufactured safely.
Solutions of polyisocyanate-polyaddition com--
pounds in polyols are also known. Thus, German Offen-
20 legungsschrift No. 2,638,759 describes solutions of
this type having solids contents of from 5 to 70~, by
weight, which are obtained by either reacting diiso-
cyanates with H-active compounds (including, among many
others, diprimary diols) in polyhydric alcohols
25 having a molecular weight of from 62 to 450 (but gener-
ally, from 62 to around 200) as reaction medium or by
subsequently dissolving the powdered, separately-
produced polyaddition compounds in the polyhydric
alcohols.
Although solutions of this type may frequently
be used as starting materials .in the production of
polyurethane plastics, they are not suitable for the
LeA 20,842
33~
production of flexible coatings and, in particular,
flexible foams. The introduction of significant amount,s
of the polyaddition compound into the polyurethane foam
formulation is only possible if relatively large
quantities of the low molecular weight polyhydric
alcohols (the solvents) are used at the same time.
This seriously affects processing reliability in the
manufacture of flexible foams (effecting the critical
links between open-cell s.tructure and shrin~age pro-
perties) or it makes the production of an open-cell
flexible foam completely impossible.
It has now surprisingly been found that oligo-
ùrethane eth-ers containing terminal OH-groups of-di-
isocyanates and dihydric, relatively short-chain poly-
ether diols form clear t stable solutions in relativelyhigh molecular weight, polyhydric polyether polyols-
optionally at elevated temperature- and that solutions `
of this type may readily be processed into flexible
foams characterized by good mechanical properties and
by good high-frequency weldability.
DESCRIPTION OF THE INVF.NTION
Accordingly, the present invention relates to
solutions of
A) from 3 to 60%, by weight, and preferably from 5
to 30%, by weight, based on the combined ether-polyol
content, of separately prepared oligo-urethane ethers
containing terminal OH-groups which are the reaction
products of
a) organic diisocyanates with
b) short-chain polyether diols having an
average molecular weight of from 200 to 800,
and preferabl~ fxom 200 to 600,
the stoichiometric ratio of a3 to b) being between
~eA 20,842
33
--5--
0.5 and 0,7 in the case of diols havin~ an average
molecular weight of from 200 to 280; to bet~een 0.5
and 0.9 in the case of diols having an average molecular
weight of from 280 to 600; and to between 0.5 and 0.75
in the case of diols having an average molecular weight
of from 600 to 800, in
B) polyether polyols containing at least two hydroxyl
groups and having an average molecular weight of from
1000 to 12,000, and preferably from 2000 to 8000.
~he present invention also relates -to a process
for the production of flame-laminatable~and high-freq-
ue~cy-weldable flexible polyurethane foams by reacting
polyisocyanates with relatively high molecular weight
compounds containing at least two hydroxyl groups,
optionally other relatively high and/or low molecular
weight compounds containing isocyanate-reactive hydrogen
atoms, and water, optionally in the presence of other
blowing agents, catalysts, ~oam stabilizers and other
additives. The solutions according to the invention
are exclusively or partially used as the relatively
high molecular weight compound.
Organic diisocyanates suitable for use in the
preparation of the solutions according to the invention
are aliphatic, cycloaliphatic, araliphatic, aromatic
and heterocyclic diisocyanates. Appropriate diiso-
cyanates are of the type described, for example, by
W. Sie~ken in Justus Liebigs Annalen der Chemie, 562,
pages 75 to 136, for example, those corresponding to
the formula: Q (NCO)2 in which "Q" is an aliphatic
hydrocarbon radical containing from 2 to 18, and pre-
ferably from 6 to 10 C-atoms; a cycloaliphatic
hydrocarbon radical containing from 4 to 15,
Le~ 20,842
and preferably from 5 to 10 C-ato~s; an aroma~ic hydr~-
carbon radical containing from 6 to 15, and preferably
from 6 to 13 C-atoms; or an araliphatic hydrocarbon
radical containing from 8 to 15, and preferably from 8
to 13 C-atoms. Examples of such diisocyanates include
1,4-tetramethylene diisocyanate; 1,6-hexamethylene di-
isocyanate; 1,12-dodecane diisocyanate; cyclobutane-l,
3-diisocyanate; cyclohe~ane-1,3- and -1,4-diisocyanate
and mixtures of these ~somers; l-isocyanato-3,3,5-tri-
methyl-5-isocyanatomethyl cyclohexane; 2,4- and 2,6-
hexahydrotolylene diisocyanate; hexahydro-1,3- and/or
-1~,4''-phe'nylene diisocyanate; perhydro-2,4l- and70r -4,4'-
diphenylmethane diisocyanate and mixtures of these
position-and/or stereoisomers; and 1,3- and 1,4- phenyl-
ene diisocyanate; 2,4- and/or 2,6-tolylene di.isocyanate
diphenyl methane-2,4l- and/or -4,4l-diisocyanate and
mixtures of these isomers~
Preferred diisocyanates for use in the production
of the oligo-urethane ethers are the isomeric tolylene
diisocyanates and diphenyl methane diisocyanates;
hexamethylene diisocyanate; dicyclohe~yl methane di-
isocyanates; and l-isocyanato-3,3,5-trimethyl-5-iso-
cyanatomethyl cyclohexane or mixtures of these iso-
cyanates. Particularly preferred are 2,4~ and/or 2,6-
tolylene dilsocyanate and the diphenyl methane di-
isocyanates and their nucleus-alkylated derivatives.
The oliyo-urethane ethers (A) containing terminal
hydroxyl groups which are dissolved (optionally, at
elevated temperature) in accordance with the invention
in relatively high molecular weight polyhydric polyether
polyols (B) are formed by separately reacting the diiso-
cyanates (a) described in the ~oregoing with short-chai~
LeA 20,842 - -
~ ~L8i~;333
polyether diols (b) having an average molecular weight
of from 200 to 800. Polyether diols of this type are
produced in the known manner, for example, by the
alkali catalyzed polymerization of propylene oxide,
optionally together with ethylene oxide (preferably up
to 50 mole percent of ethylene oxide) onto starter
compounds preferably containing two reactive hydrogen
atoms. Suitable starter compounds include, for example,
water or dihydric diols, such as ethylene glycol; 1,2-
or 1,3-propylene glycol; 1,2-, 1,3~ or 1,4-butylene
glycol; 1,6-hexane diol; 1,8-octane diol; neopentyl
glycol; 1,4 bis-hydroxymethyl cyclohexan-ei methyl-l,
~3-propane.diol; resorcinol; hydroquinone; or 2,~is(4-
hydroxyphenyl)-propane. Monoamines such as methyl
amines, stearyl amine, cyclohexyl amine, aniline and
mixtures of these compounds are also suitable.
It is particularly preferred to use polyether
diols having an average molecular weight of from 200
to 600, especially polypropylene glycols which may
contain up to 30 mole percent of ethylene oxide units.
Relatively high molecular weight polyether
polyols having molecular weights in the range from
1000 to 12,000 (preferably in the range of from 2000
to 8000) are obtained in known manner, for example,
by the alkali-catalyzed polymerization of propylene
oxide, optionally together with up to 60 mole percent,
and pxeferably with up to 30 mole percent, of ethylene
oxide, onto dihydric or polyfunctional starter compounds
containing reactive hydrogen atoms. Examples of
suitable starter compounds include water; ethylene
glycol; 1,2- or 1,3-propylene glycol; 1,2~, 1,3- or
1,4- butylene glycol; 1,6-hexane diol; 1,8-octane
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diol; neopentyl glycol; 1,4~~is-hydroxymethyl cyclo- i
hexane; 2-methyl-1,3-propane diol; glycerol; trimethylol
ethane and propane; pentaerythritol; mannitol; sorbitol;
formitol; and cane sugar. Additional examples include
resorcinol; hydroquinone; 2,2-bis-(4~hydroxy-phenyl)-
propane; ammonia; methylamine; ethylene diamine; tetra-
methylene or hexamethylene diamine; ethanolamine; di-
ethanolamine; triethanola-mine; aniline; 2,4- and 2,6-
diaminotoluene; and polyphenyl polymethylene polyamines
of the type obtained by condensing aniline with formal-
dehyde, and also mixtures of these compounds. Other
suitable starters are resin-like materials of the novolak
and resol type.
Additional suitable polyether polyols are de-
scribed in terms of their composition and modification
in German Offenlegungsschrift No, 2,920,501. ~
Other polyhydroxyl components suitable for use
in the production of foams by standard methods are
described, for example, in German Offenlegungsschrift
20 No: 2,854,384, page 14 and pages 16 to 19; other low
molecular weight compounds are described on pages 20
to 25 of that reference; and other polyisocyanates
suitable for foam formation are described on pages 8
to 11 of that reference.
The reaction of the diisocyanates with the
dialcohols by which the oligo-urethane ethers are
separately produced is carried out in known manner
at temperatures in the range of from about 0 to 200C,
and preferably at temperatures in the range of from
30 30 to 150Co For example, -the hydroxyl component may
be initially introduced and the diisocyanate added
either all at once or gradually, the temperature being
LeA 20,842 -~
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33
kept constant by external or internal cooling ox to
rise under the effect of the exothermic reaction without
cooling.
The oligo-urethane ethers according to the
invention may of course also be continuously produced.
The hydroxyl component may be combined with the iso-
cyanate in a statistical o~ dynamic straight flow mixer,
the reaction mixture being delivered from this mixer
to a following stirrèr-equipped vessel in which the
reaction is completed, for example. Cascades of
stirrer-equipped vessels or Zellar reactors are also
s~itable for continuously carxying out the polyaddition
reaction.
If desired, the reaction may be accelerated by
known catalysts commonly used in polyurethane chemistry,
such as, for example, tertiary amines, amidines, metal
hydroxides, alcoholates, phenolates or carboxylates or
carboxylates and chelates of the transition metals.
Finally, solutions according to the invention
are obtained by dissolving the oligo-urethanes in the
relatively high molecular weight polyether polyols
mentioned above using known mixi~gunits.
Considerable importance is attached to the
stoichiometric NCO/OH-ratio between the diisocyanate
and the short-chain polyether diol in order to both
obtain a clear solution of the oligo-urethane ethers
in the relatively high molecular weights, poly-
functional polyether polyols and to maintain the
viscosity preferably beIow 3500 mPas required for the
proauction of flexible foams. As mentioned above,
this ratio should amount to between 0.5 and 0.7 in
the case of dialcohols having an average molecular
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--10--
weight of from 200 to.~280, to between a~out 0,5 and 0.9
in the case of dialcohols having an average moleculax
weight of from 280 to 600 and to between about 0.5 and
0.75 in the case of dialcohols having an average molecu-
lar weight of from 600 to 800.
Although the high content of oligo-urethane
ethers in the solution may amount to between 3 and 60%,
by weight, concentrations of from S to 30~ by weight
are preferred. On the one h~nd, solutions of the type
in question - in concentrations below 5%, by weight-
only bring about minimal changes in the properties of
the polyurethane plastics produced from ~~he solutions,
while on the other hand, concentrations above 30~, by
weight, can frequently give rise to high viscosities
which have an adverse effect upon processing.
The solutions according to the invention are used
in the usual way as modified polyether polyols for the
production of flexible polyurethane foams. The flex-
ible foams obtainable in this way may be welded very
effectively by means of known welding machines and,
in addition, are characterized by excellent overall
properties.
Comparison in the production of flexible poly-
urethane foams of the oligo-urethane soluti.ons
according to the invention wîth other foam ~ormulations
(cf., Foaming Examples 6 through 9 with E~amples
10 and 11), in which the polyether diols are used as
additives or (together with polyether polyols of
relatively high molecular weight) as urethane-modi-
fied polyols, proves the superiority of the formersolutions. This advantage is reflected in p:a~ticular
in the safety of the foaming-processj in the properties -
~of the resulting foams and in the low
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333
vi~cosity of the polyol component,
The addition of corresponding quantities of
linear dialcohol leads either to shrinkage or gives
a foam characterized by poor mechanical properties
(Foam Examples 10 and 11). If the addition of linear
dialcohol and diisocyanate is carried out in polyether
as the reaction medium (cf., Solutions Bl to B4),
solutions of relatively high ~iscosity are obtained
because of the subse~uent reaction o the polyether.
Further, if the reaction of~dialcohoi and diisocyanate
were to be carried out in polyethers predominantly
containing primary OH-terminated groups, the end
products would have extremely high viscosities e~en
despite very low solids contents.
In addition to the starting components already
mentioned, water and/or other blowing agents, acti-
vators, and optionally, other known additives and
auxiliaries of the type mentioned in the publications
cited earlier (for example, on pages 25 to 31 of
20 German Offen:Legungsschrift No. 2,854,384) may be used
in the production of flexible foams in accordance
with the invention.
According to the invention, the reaction com-
ponents are reacted by the known one-shot process,
by the prepolymer process or by the semi-prepolymer
process, often using machines, for example of the
type described in US Patent No. 2,764,565. Information
on processing machines which may also be used in
accordance with the invention can be found in Kunststoff-
Handbuch, Vol. VII, b~ Vieweg and Hochtlen, Carl-
H~nser-Verlag, Munich 1966, fox example, on page 121 to
247.
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3~
-12-
In the production of foams,in accordance with
the invention, foaming is often carried out with the
reaction mixture introduced into a mold where it foams
and forms the molding. Suitable mold materials include
metals, such as aluminumt or plastics, such as epoxide
resin. In~mold foaming may be carried out in such a
way that the molding has a cellular structure at its
surface, although it may also be carried out in such a
way that the molding has a compact skin and a cellular
core. In this conné~tion, -t is possible, in accordance
with the invention, to introduce foamable reaction
mixture into the mold in such a ~uantity that the foam
formed just ~ills the mold. However, it is also possible
to introduce into the mold more foamable reaction
mixture than is required for filling the interior of the
mold with foam (called "overcharging" and described
for example, in VS Patent Nos. 3,178,490 and 3,182,104).
Where foaming is carried out in molds,known
"external release agents" such as silicone oils, are
fre~uently used. However, it is also possible to use
so-called "internal release agents", optionally in
admixture with external release agents, of the type
known, fox example, from German Offenlegungsschriften
2,121,670 and 2,307,589.
~ccording to the invention, it is also possible
to produce cold-hardening foams (cf., British Patent
No. 1,162,517 and German Offenlegungsschrift No.
~,153,086).
However, it is, of course, also possible to
produce foams by block foaming or by the known laminator
process.
The invention is illustrated by the following
Examples in which the quantities quoted xepresent - ¦
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. . .
3~3
.
~13-
parts by wei~ht or percentages by weight, unless
otherwise indicated
The designations used have the following
meanings:
Dialcohol I: polypropylene oxide having an
OH-number of 515
Dialcohol II: polypropylene oxide having an
. OH-number of 265
Dialcohol III: polypropylene glycol ethoxylate
lC (15% of ethylene oxide units at
the chain ends) ha~ing an OH-
number of 150 ---
Glycol (b) I: polypropylene ether diol, OH-
number 515
Glycol (b) II: polypropylene ether diol, OH-
number 265
Polyether I: started with 90% glycerol and
10% 1,2-propylene glycol; 10%
ethylene oxide and 90~ propylene
oxide in the chain; more than
95 mole percent of secondary
OH-groups; OH-number 46
Polyether K: started with 90% glycerol and 19%
1,2-propylene glycol; 10% of
ethylene oxide and 90~ of
propylene oxide units in the
chain; OH-number 46
Polyether L: started with trimethylol. propane,
18% of ethylene oxide and 82%
of propylene oxide units in the
chains; approximately 90 mole
percent of primary OH-terminal
groups, ~H-number 35
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333
TDI 65: . tolylene diisocyanate (65% 2,4-
and 35% 2,6 isomer)
TDI 80. tolylene diisocyanate (80~ of 2,4~
and 20% of 2,6-isomer)
MDI: diphenyl methane-4,4'-dii.socyanate
HDI: 1,6-hexamethylene diisocyanate
EXAMPLES
1. Production of the- solut~ions
EXAMPL~ A 1:
- -
69.6 (=0.4 mole) of tolylene diisocyanate (TDI
80) are added over a period of 10 to 15 minutes at
90_to. 100C~to 211.5 g (-0.5 mole) of a polypropylene
oxide having an OH-number of 265. The reaction mixture
is then stirred at 100C until no more NCO-groups
can be detected ~2 to 5 hours). The oligo-urethane
ether formed is then stirred into 2530 g of Polyether
K heated to 100C. The clear solution (solids content
10%) has a viscosity of 1100 mPas at 2SC.
The following solutions of oligo-urethanes in
polyethers of relatively high molecular weight are
prepared in exactly the same way.
LeA 20,842
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2. COMPA~I'SON EXAMPLES B 2 and B 4
EXAMPLE B 2:
87 g of TDI 80 (= 0.5 mole) are added at 100C
to 217.9 g (= 1 mole) of dialcohol I and 1219.6 g of
Polyether K, followed by stirring for 5 hours. The
clear solution (solids content 20%) has a viscosity
of 2450 mPas at 25C.
Solution B 4 is prepared in exactly the same way.
Alcohol component:, `,,Dialcohol II
Isocyanate component: TDI 80
Molar ratic of dialcohol to diisocyanate: 7:6
High molecular weight polyether: Polyether K
'Soli'ds cont'ent: 20% ~~~'
Viscosity at 25C: 5750 mPas.
3. APPLICATION EXAMPLES
Production of flexible polyurethane foams
Flexible foams were produced from solutions
A 1 to A 5, B 1 to B 4 and C l to C 9. In each case,
flexible foams were produced by the hand foaming
process (through mixing of the polyols with stabilizer,
water and activator; then addition of the isocyana-te;
and foaming after further mixing in a paper packet).
The fo~ms obtained were welded with a flat
electrode 1 cm wide and 10 cm long (surface area
10 cm ) under a pressure of 9 kp/cm using 10 mm
thick foam sheets (foam/foam) and a composite system
of a polyamide velours, 8 mm foam sheet and a poly-
amide Charmeuse. The welding voltage was 650 V and
the current 480 m~. The HF-weldiny unit used was
an HG 600 S high-frequency generator (manufactured
by the Herfurth Company of Hamhurg-Altona), The
frequency was 27,12 MHz and the generator output 600 W.
t
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