Note: Descriptions are shown in the official language in which they were submitted.
1 3 3 7 4 ¢ ~ Mo-3095
~eA 25,404
PROCESS FOR THE PREPARATION OF AQUEOUS
POLYURETHANE-POLYUREA DISPERSIONS
BACKGROUND OF THE lNV~NLlON
Field of the Invention
This invention relates to a process for the
preparation of stable aqueous dispersions of
polyurethane-polyureas, to the dispersions obtained and
to their use for the production of coatings.
Description of the Prior Art
Polyurethane-polyureas have numerous commercial
applications, for example as a & esives or coating
compounds for various substrates such as textiles,
plastics, wood, glass fibers, leather and metals.
Chemical resistance, abrasion resistance, toughness,
tensile strength, elasticity and durability are some of
the possible properties of these materials.
It is known in the art that polyurethane-
polyureas may be applied as coating compounds or
adhesives from solutions in organic solvents. This is
economically disadvantageous due to the high cost of the
solvents, but even more important is the atmospheric
pollution caused by the solvents.
Numerous experiments have therefore been
undertaken to produce polyurethane-polyurea coatings
from dispersions of these polymers in water. This
procedure is economical since water is used as solvent
and causes no atmospheric pollution. Polyurethane-
polyureas are, however, incompatible with water, i.e.
they do not form stable dispersions in water unless they
are produced by special manufacturing processes or with
the aid of special additives.
In earlier methods for the preparation of
stable dispersions of polyurethane-polyureas, external
emulsifiers were used for dispersing and stabilizing the
Mo-3095
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polymers in water, for example as described in
US-A-2,968,575. Although dispersions could be prepared
by this method, the coatings obtained had serious
disadvantages, for example a high sensitivity to water
5 due to the presence of these emulsifiers.
In subsequent developments, emulsifiers which
could be chemically incorporated in the polyurethane-
polyurea chain were used. Such ionic emulsifiers are
described, for example, in US-A-3,479,310. The use of
10 chemically incorporated nonionic emulsifiers is
described, for example, in US-A-3,905,929,
US-A-3,920,598 and US-A-4,190,566. Further improvements
in the properties of coatings obtained from
polyurethane-polyurea dispersions were achieved by the
15 combination of ionic and nonionic starting components,
as described, for example, in US-A-4,092,286,
US-A-4,237,264 and US-A-4,238,378.
These developments led to dispersions with
improved stability and lower proportions of hydrophilic
20 starting components. Since these dispersions contained
a lower proportion of hydrophilic starting components,
they could be used for the formation of coatings with
improved water resistance and less loss of mechanical
strength in the swelled state. The preparation of
25 polyurethane-polyurea dispersions obtained by dispersing
prepolymers containing isocyanate end groups in water
and then chain lengthening with diamines is described in
US-A-4,066,591. The prepolymers containing ionic groups
mentioned in US-A-4,066,591 are obtained by a simple
30 method of reacting an excess of isocyanate groups with
starting components cont~;ning isocyanate-reactive
groups and ionic or potentially ionic groups until the
theoretical amount of free isocyanate groups are
obtained. No particular sequence of reactions of the
35 starting components is described.
Mo-3095
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US-A-4,408,008 also describes the preparation
of prepolymers cont~;ning isocyanate groups followed by
dispersion in water. In this case the prepolymers are
prepared from organic polyisocyanates, compounds
5 containing at least two isocyanate-reactive groups,
organic compounds cont~;n;ng hydrophilic ethylene oxide
units and optionally organic compounds cont~;n;ng ionic
or potential ionic groups.
Dispersions of tertiary amine salts of
10 polyurethane-ureas prepared from polyamines such as
triamines and urethane prepolymers containing isocyanate
end groups and carboxyl groups are described in
US-A-4,203,883. In accordance with this invention, the
isocyanate-terminated prepolymers may be prepared by the
- 15 reaction of isocyanates and polyols in a simultaneous or
a stepwise process. The said disclosure does not
mention that the stepwise method of reaction has any
particular influence on the properties of the resulting
dispersions.
Cross-linked polyurethane dispersions obtained
from isocyanate-terminated prepolymers containing
carboxylate groups are described in US-A-4,554,308.
Examples are given in which the carboxyl groups are
incorporated in the prepolymer in the second step of a
25 stepwise reaction sequence. Here again, there is no
mention of the reaction method having any particular
influence on the properties.
One disadvantage of the known polyurethane-
polyurea dispersions is that a relatively large quantity
30 of ionic gro~ps must be incorporated if good
dispersibility is to be achieved.
It is an object of the present invention to
provide an improved process for the preparation of
polyurethane-polyurea dispersions in which the quantity
35 of ionic groups required for dispersion i8 reduced
Mo-3095
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_
without sacrificing the other desirable properties of
coatings or films prepared from these dispersions.
SUMMARY OF THE lNV~:NLlON
The present invention is directed to a process
5 for the preparation of stable polyurethane-polyurea
dispersions in a multi-stage process by forming an
isocyanate-terminated prepolymer having an ionic group
content of up to about 50 milliequivalents per 100 g of
prepolymer by reacting an organic polyisocyanate a) with
10 at least two isocyanate-reactive components bl) and b2)
wherein component bl) has at least one ionic or
potential ionic hydrophilic group, characterized in that
1) the isocyanate a) is initially reacted with
component bl), and
2) the resulting product is then reacted with
component b2) and optionally with a component
b3) cont~in;ng ethylene oxide units to form a
prepolymer, and
3) the resulting prepolymer is dispersed in water.
The present invention further relates to
products obtained according to this process and to their
use for the preparation of coatings on flexible or rigid
substrates and in particular to their use as adhesives.
DET~TT.T"n DESCRIPTION OF THE lNV~:NLlON
In a preferred embodiment, an isocyanate excess
is employed during the whole process of preparation. In
another preferred embodiment, the prepolymers are
straight chain prepolymers with a molecular weight of up
to about 25,000. In another preferred embodiment, the
30 prepolymer is reacted with a chain lengthening agent
during or after dispersion in water. In a particularly
preferred embodiment, compound b2) is a compound with a
molecular weight of at least about 1500.
The process according to the invention gives
35 rise to dispersions which are more stable and more
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finely divided for a given ionic group content in the
prepolymer than those obtained by known processes. In
many cases, finely divided, stable dispersions are
obtained with a given ionic group content when only
5 unstable and sedimenting products can be obtained with
such an ionic group content by the known processes.
The process according to the invention enables
dispersions with a given average particle size to be
produced from smaller quantities of ions than are
10 required in the prior art processes. By using smaller
quantities of hydrophilic groups, the present invention
enables coatings and adhesives to be prepared with a
lower tendency to water absorption and hence with less
impairment in the mechanical properties resulting from
15 the absorption of water. This constitutes a
considerable advantage.
The following are examples of suitable starting
components a) for the process according to the
invention.
Diisocyanates of the formula Q(NC0)2 in which Q
denotes an aliphatic hydrocarbon group with 4 to 18
carbon atoms, a cycloaliphatic hydrocarbon group with 6
to 15 carbon atoms, an aromatic hydrocarbon group with 6
to 15 carbon atoms, or an araliphatic hydrocarbon group
25 with 7 to 15 carbon atoms. Examples of these
diisocyanates include tetramethylene diisocyanate,
hexamethylene diisocyanate, dodecamethylene
diisocyanate, 1,4-diisocyanatocyclohexane, l-isocyanato-
3,3,5-trimethyl-5-isocyanatomethylcyclohexane, 4,4'-
30 diisocyanatodicyclohexyl methane, 4,4'-diisocyanato-
dicyclohexylpropane-(2,2), 1,4-diisocyanatobenzene, 2,4-
diisocyanatotoluene, 2,6-diisocyanatotoluene, 4,4'-
diisocyanatodiphenyl methane, 4,4'-diisocyanatodiphenyl
propane-(2,2), p-xylylene diisocyanate, a,a,a~a~-tetra
35 methyl-m- and -p-xylylene diisocyanate, and mixtures of
the above mentioned compounds.
Mo-3095
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1 3~7~
In the process according to the invention, it is
also possible in principle to use the starting components
a) exemplified above in combination with higher
functional low molecular weight polyisocyanates such as
5 the reaction product of 3 mol of 2,4-diisocyanato-
toluene with 1 mol of trimethylolpropane and/or in
combination with monofunctional isocyanates such as
phenyl isocyanate, hexyl isocyanate or n-dodecyl
isocyanate. It is also possible to use monofunctional
10 isocyanates containing polyether chains with incorporated
ethylene oxide units, for example of the type mentioned
in US Patent Specifications 3,920,598 and 4,237,264.
When such monofunctional isocyanates are used,
however, it is generally necessary to add higher than
difunctional starting components to prevent premature
chain breaking, especially when preparing high molecular
weight polyurethanes. For the process according to the
invention it is preferred to use difunctional isocyanates
of the type exemplified above as starting component a).
Component bl) preferably includes compounds
cont~;ning isocyanate-reactive groups with anionic groups
or groups capable of conversion into anionic groups as
described, for example, in US-P 3,765,992, US-P 3,479,310
or US-P 4,108,814.
Aliphatic diols containing sulphonate groups
according to DT-OS 2,446,440 and DT-OS 2,437,218 are
preferably used as anionic or potential anionic starting
components bl) for the process according to the
invention.
The particularly preferred (potential) ionic
starting components contain sulphonate groups and include
sulphonate diols corresponding to the formula
MO-3095 - 6 -
' 1 337445
H-(OCH-CH2)n~~(A)o~CH~(B)p-O-(CH2-CH-O)mH
CH3 (IH2) ~ CH3
wherein
A and B stand for identical or different divalent
aliphatic hydrocarbon groups containing 1 to 6
carbon atoms,
10 R stands for hydrogen, an aliphatic hydrocarbon
group with 1 to 4 carbon atoms or a phenyl
group,
X~ stands for an alkali metal cation or an
optionally substituted ammonium group,
15 n and m stand for identical or different integers from 0
to 30,
o and p each represents 0 or 1 and
q stands for an integer from 0 to 2.
Propoxylated adducts of 2-butene diol-(1,4) and
20 a sulphite, in particular NaHSO3, wherein n + m = 4, are
examples of particularly preferred compounds bl). The
compounds bl) are preferably used in solution, for
example, in toluene.
Suitable starting components b2) for the
25 process according to the invention include compounds
containing at least two isocyanate-reactive groups, in
particular organic compounds which contain a total of 2
amino groups, thiol groups, carboxyl groups and/or
hydroxyl groups and have molecular weights of 61 to
30 about 10,000, preferably 300 to about 6000, and most
preferably about 1500 to 5000. The corresponding
dihydroxyl compounds are preferably used. Small
proportions of compounds which are trifunctional or
higher functional in isocyanate polyaddition reactions,
35 such as trimethylol propane, may be included for
Mo-3095
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1 337445
obtaining a certain degree of branching in the same way
that trifunctional or higher functional polyisocyanates
may be used for the same purpose, as already mentioned.
The preferred hydroxyl compounds are hydroxy-
5 polyesters, hydroxypolyethers, hydroxypolythioethers,hydroxypolyacetals, hydroxypolycarbonates and/or
hydroxypolyester amides of the type known in
polyurethane chemistry. Suitable hydroxypolyesters
include, for example, the reaction products of
10 polyhydric, preferably dihydric alcohols (with the
optional addition of trihydric alcohols) and polybasic,
preferably dibasic carboxylic acids. Instead of free
polycarboxylic acids, the corresponding polycarboxylic
acid anhydrides or corresponding polycarboxylic acid
15 esters of lower alcohols or mixtures thereof may be used
for the preparation of the polyesters. The
polycarboxylic acids may be aliphatic, cycloaliphatic,
aromatic and/or heterocyclic and may be substituted,
e.g. with halogen atoms, and/or unsaturated. Examples
20 include succinic acid, adipic acid, suberic acid,
azelaic acid, sebasic acid, phthalic acid, isophthalic
acid, trimellitic acid, phthalic acid anhydride,
tetrahydrophthalic acid anhydride, hexahydrophthalic
acid anhydride, tetrachlorophthalic acid anhydride,
25 endomethylene tetrahydrophthalic acid anhydride,
glutaric acid anhydride, maleic acid, maleic acid
anhydride, fumaric acid, dimeric and trimeric fatty
acids such as oleic acid optionally together with
monomeric fatty acids, dimethyl terephthalate, and
30 terephthalic acid-bis-glycol ester. Examples of
suitable polyhydric alcohols include ethylene glycol,
propylene glycol-tl,2) and -(1,3), butylene glycol-(1,4)
and -(2,3) and -(1,3), hexane diol-(1,6), octane
diol-(1,8), neopentyl glycol, cycloheY~ne dimethanol
35 (1,4-bis-hydroxymethyl cyclohexane), 2-methyl-1,3-
Mo-3095
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1 337445
propane diol, glycerol, trimethylol propane, hexane
triol-(1,2,6), butane triol-(1,2,4), trimethylol ethane,
pentaerythritol, quinitol, mannitol and sorbitol, methyl
glycoside, diethylene glycol, triethylene glycol, tetra-
5 ethylene glycol, polyethylene glycols, dipropyleneglycol, polypropylene glycols, dibutylene glycol and
polybutylene glycols. The polyesters may contain a
proportion of carboxyl end groups. Polyesters of
lactones such as ~-caprolactone or hydroxycarboxylic
10 acids such as ~-hydroxy-caproic acid may also be used.
The polyethers with preferably two hydroxyl
groups which may be used are also of known type and may
be prepared, for example, by the polymerization of
epoxides such as ethylene oxide, propylene oxide,
15 butylene oxide, tetrahydrofuran, styrene oxide or
epichlorohydrin, either on their own, e.g. in the
presence of BF3, or by chemical addition of these
epoxides, optionally as mixtures or successively, to
starting components containing isocyanate-reactive
20 groups such as alcohols or amines. Examples include the
previously mentioned polyhydric alcohols and also water,
ethylene glycol, propylene glycol-(1,3) or -(1,2), 4,4'-
dihydroxy-diphenyl propane or aniline.
Polyethers modified with vinyl polymers such as
25 the compounds obtained by the polymerization of styrene
or acrylonitrile in the presence of polyethers (US
Patent Specifications 3,383,351, 3,304,273, 3,523,093
and 3,110,695 and German Patent Specification 1,152,536)
are also suitable. A portion of higher functional
30 polyethers, which may optionally be added, are obtained
analogously by the known process of alkoxylation of
higher functional starting molecules such as ammonia,
ethanolamine, ethylene ~;~mine or sucrose.
Among the polythioethers should be particularly
35 mentioned the products obtained by the condensation of
Mo-3095
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thiodiglycol on its own and/or with other glycols,
dicarboxylic acids, formaldehyde, amino carboxylic acids
or amino alcohols. The products obtained are polythio
mixed ethers, polythio ether esters or polythio ether
5 ester amides, depending on the coreactants.
Suitable polyacetals include e.g. the compounds
which can be prepared from glycols such as diethylene
glycol, triethylene glycol, 4,4'-diethoxy-diphenyl-
dimethyl methane, hexane diol and formaldehyde.
10 Polyacetals suitable for the purpose of the invention
may also be prepared by the polymerization of cyclic
acetals.
Suitable polycarbonates with hydroxyl groups
include those of known type which may be prepared, for
15 example, by the reaction of diols such as propane
diol-(1,3), butane diol-(1,4) and/or hexane diol-(1,6),
diethylene glycol, triethylene glycol or tetraethylene
glycol with phosgene or diaryl carbonates such as
diphenyl carbonate.
Suitable polyester amides and polyamides
include the predominAntly linear condensates obtained
from polyvalent saturated or unsaturated carboxylic
acids or their anhydrides and polyvalent saturated or
unsaturated amino alcohols, diamines, polyamines or
25 mixtures thereof. Polyhydroxyl compounds already
containing urethane or urea groups may also be used.
Low molecular weight polyols may also be used
as all or part of the hydroxyl compounds, e.g. ethane
diol, propane diol-(1,2) and -(1,3), butane diol-(1,4)
30 and -(1,3), pentane diols, hexane diols, trimethylol
propane, heXAne triols, glycerol and pentaerythritol.
Small quantities of monofunctional alcohols may alæo be
used, e.g. stearyl alcohol.
Representatives of the above mentioned
35 polyisocyanate and hydroxyl compounds suitable for the
Mo-3095
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1 337445
process according to the invention are described, for
example, in High Polymers, Volume XVI, "Polyurethanes,
Chemistry and Technology" by Saunders-Frisch,
Interscience Publishers, New York, London, Volume I,
5 1962, pages 32 to 42 and pages 44 to 54 and Volume II,
1964, pages 5 to 6 and 198 to 199, and in Kunststoff-
Handbuch, Volume VII, Vieweg-Hochtlen, Carl-Hanser-
Verlag, Munich, 1966, e.g. on pages 45 to 71.
Chain lengthening agents with a molecular
10 weight below 300 which may be used in the process
according to the invention for the preparation of the
self dispersible polyurethanes include the low molecular
weight diols described for the preparation of the
dihydroxy polyesters, diamines such as diamino ethane,
15 N,N'-dimethyl-~;Am;~o ethane, 1,6-~;Am;no hexane,
piperazine, 2,5-dimethyl piperazine, 1-amino-3-amino-
methyl-3,5,5-trimethyl-cyclohexane, 4,4'-~;Am;nodicyclo-
hexylmethane, 1,4-diaminocyclohexane or 1,2-propylene-
diamine as well as hydrazine, amino acid hydrazides,
20 hydrazides of semicarbazido carboxylic acids,
bis-hydrazides and bis-semicarbazides.
Chain breaking agents with a molecular weight
below 300 include monofunctional alcohols such as
methanol, ethanol, n-octanol or n-dodecanol or
25 especially ammonia or primary amines, as described, for
example, in DE-A-2,637,690.
In a preferred embodiment, the prepolymers
prepared according to the invention contain terminally
or laterally incorporated hydrophilic ethylene oxide
30 units in amounts of up to about 15Z by weight. The
compounds b3) used for introduction of these ethylene
oxide units include monoisocyanates contA;n;ng terminal
ethylene oxide units, diisocyanates containing lateral
ethylene oxide units and/or compounds containing
35 isocyanate-reactive groups which are monofunctional or
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difunctional in isocyanate polyaddition reactions and
contain terminal or lateral ethylene oxide units, for
example as described in DE-OS 2,314,512, DE-OS
2,314,513, DE-OS 2,551,094, DE-OS 2,651,506, US-P
5 3,920,598 or US-P 3,905,929 or mixtures of these
compounds.
Preferred starting components b3) cont~;n;ng
nonionic hydrophilic groups include compounds of the
formula:
R' R'
HO-CH-CH2-N-CH2-CH-OH (I)
bo -NH-R-NH-CO-Z-X-Y-R"
and/or compounds of the following formula:
OCN-R-N-CO-NH-R-NCO (II)
C10
Z-X-Y-R
Particularly preferred starting components b3)
are those of the first mentioned formula (I).
In the above formulae (I) and (II)
R stands for a divalent group obtainable by removal
of the isocyanate groups from a diisocyanate of
the above mentioned type corresponding to the
formula R(NCO)2,
R' stands for hydrogen or a monovalent hydrocarbon
group with 1 to 8 carbon atoms, preferably
hydrogen or a methyl group,
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1 337445
R" stands for a monovalent hydrocarbon group with 1
to 12 carbon atoms, preferably an unsubstituted
alkyl group with 1 to 4 carbon atoms,
X stands for a polyalkylene oxide chain having 5 to
90, preferably 20 to 70 chain members, at least
about 40Z of which, preferably at least about 65~,
are based on ethylene oxide units, the remainder
based on propylene oxide, butylene oxide or
styrene oxide units in addition to the ethylene
oxide units, propylene oxide units being preferred
among the last mentioned units.
Y stands for oxygen or -NR"'- wherein R"' has the
same meaning as R" and
Z stands for a group which has the same meaning as Y
but may in addition represent NH.
The compounds corresponding to the above
mentioned formulae (I) and (II) may be prepared by the
processes according to DT-OS 2,314,512 or 2,314,513 but
it should be noted in addition to what is disclosed in
20 the said documents that instead of the monofunctional
polyether alcohols mentioned there as starting materials
there may also be used compounds in which the polyether
segment contains not only ethylene oxide units but also
up to 60% by weight, based on the polyether segment, of
25 propylene oxide, butylene oxide or styrene oxide units,
preferably propylene oxide units. The presence of such
"mixed polyether segments" may in special cases afford
specific advantages.
Other preferred hydrophilic components to be
30 incorporated which contain terminal or lateral ethylene
oxide units are compounds of the general formula
H-Y'-X-Y-R"
35 and/or compounds of the general formula
Mo-3095
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OCN-R-NH-CO-Z-X-Y-R"
wherein
5 X, Y, Z, R and R" have the meanings defined above and
Y' corresponds to the definition of Y but may in
addition stand for NH.
Monofunctional polyethers are preferably used,
but preferably only in molar quantities~l0Z of the
10 quantity of polyisocyanate used to ensure the build up
of high molecular weights of the polyurethane.
When relatively large quantities of
monofunctional polyethers containing ethylene oxide
groups are used, it may be advantageous also to include
15 compounds which are trifunctional in isocyanate addition
reactions.
The monofunctional, hydrophilic components are
prepared according to the process described in US-P
3,905,929 and 3,920,598 of alkoxylating monofunctional
20 starting compounds such as n-butanol with ethylene oxide
and optionally other alkylene oxides such as propylene
oxide. The resulting product may be further modified by
reaction with an excess of diisocyanate or by a reaction
with ammonia resulting in the formation of the
25 corresponding primary amino polyethers.
The proportion of anionic or potential ionic
groups present is calculated to provide about 0.5 to 50
milliequivalents, preferably about 0.5 to 30
milliequivalents and more preferably about 0.5 to 20
30 milliequivalents of these groups per 100 g of solids.
The proportion of incorporated hydrophilic ethylene
oxide units may be about 0 to 15a by weight, preferably
0.8 to 10Z by weight and more preferably about 1.0 to 6
by weight, based on the prepolymer solids content.
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The isocyanate-terminated prepolymers according
to the invention are prepared by a multi-stage process.
In the first step of the process, the polyisocyanate is
reacted with the whole quantity or at least a portion of
5 starting component bl) which contains ionic groups or
potentially ionic groups. The reaction temperature is
preferably kept below about 150C, preferably about 50
to 130C. In the subsequent step(s) of preparation of
the prepolymer, isocyanate-reactive components b2) and
10 optionally b3) are reacted with the product of the first
reaction stage. The equivalent ratio of isocyanate
groups to isocyanate-reactive groups is preferably about
1.1:3, more preferably about 1.2:2 and most preferably
about 1.2:1.8. If the organic isocyanate is reacted
15 with all the isocyanate-reactive compounds bl), b2) and
b3) at the same time, the products obtained are inferior
in their properties compared with those obtained by the
process according to the invention, as can be seen from
the stability of the dispersion or the particle size.
The reaction for the preparation of the
prepolymers is preferably continued until the free
isocyanate group content is equal to the theoretical
value or slightly below it. The resulting prepolymer
should contain about 1 to 8Z by weight of free
25 isocyanate groups, preferably about 1 to 5Z by weight.
The isocyanate polyaddition reaction may be carried out
in the presence of catalysts such as organo tin
compounds, tertiary amines, etc. although the reaction
is preferably carried out without catalysts.
The prepolymers may be prepared in the presence
or absence of solvents. Examples of suitable organic
solvents which are inert towards isocyanate groups
include dimethyl formamide, esters, ethers, ketoesters,
ketones such as methylethyl ketone or acetone, glycol
35 ether esters, chlorinated hydrocarbons, aliphatic and
Mo-3095
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alicyclic pyrrolidones substituted with hydrocarbons
such as N-methyl-2-pyrrolidone, hydrogenated furans,
aromatic hydrocarbons and mixtures thereof. Although it
is not necessary to use solvents in the preparation of
5 the prepolymer, solvents may be helpful in keeping the
reactants in the liquid phase and improving the control
of the reaction temperature. The quantity of the
solvent optionally used may vary over a wide range but
should be sufficient to ensure that the viscosity of the
10 prepolymer will be low enough to enable the polyurethane
dispersions according to the invention to be formed,
although successful dispersion may be achieved with
relatively high viscosities of the prepolymer or
prepolymer solution at the dispersion temperature.
15 Viscosities below 100 centipoise may be employed;
however, viscosities above 10,000 centipoise are also
suitable for obtaining stable dispersions with only mild
stirring. If solvents are used, they are in most cases
added in quantities of about 0.01 to 10 parts by weight,
20 preferably about 0.02 to 2 parts by weight, based on the
weight of the prepolymer. The presence of solvents in
the prepolymer or in the polyurethane is not necessary
for obtaining stable, aqueous dispersions. When
solvents are used for the preparation of the prepolymer
25 and/or of the polyurethane, it is in many cases
desirable to remove at least part of the solvent from
the aqueous dispersion. The solvent used should
preferably have a lower boiling point than water so that
it can be removed from the aqueous dispersion, for
30 example by distillation. Removal of the low boiling
solvent should be carried out under mild conditions
which will not damage the polyurethane. If solvents
with boiling points higher than that of water are used
such as dimethyl formamide or N-methyl pyrrolidone, they
35 remain in the aqueous polyurethane dispersion. They
Mo-3095
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accelerate coalescence of the polyurethane particles
during film formation.
When potential ionic groups are incorporated in
the polyaddition product, they are converted into ionic
5 groups in a known manner by neutralization.
When potential anionic groups of the prepolymer
are neutralized, the prepolymer becomes hydrophilic and
can be converted into a stable dispersion. The
potential or unneutralized anionic groups are not
10 sufficiently hydrophilic for the formation of stable
dispersions. It is therefore necessary to neutralize a
sufficient quantity of potential anionic groups so that
in combination with any nonionic hydrophilic groups
optionally used, they will ensure the formation of
15 stable aqueous dispersions. In general, at least about
50Z, preferably at least about 80Z of the potential
anionic groups are converted into anionic groups by
neutralization. Although higher proportions of
potentially anionic groups may be left unneutralized,
20 these unneutralized groups provide no advantage and may
reduce the improvement in resistance to hydrolysis
provided according to the invention. If only small
quantities of potential anionic groups are incorporated
in the molecule, it may be necessary to neutralize all
25 these groups in order to render the compounds
sufficiently hydrophilic.
The step of neutralization may be carried out
1. before prepolymer formation, by treating
the compounds containing the potential
ionic groups,
2. after prepolymer formation but before
dispersion of the prepolymer or
3. during dispersion, by adding the
neutralizing agent to all or part of the
water used for dispersion.
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The reaction between the neutralizing agent and
the potential anionic groups may be carried out at
temperatures of about 20C to 150C, preferably below
about 100C, more preferably about 30C to 80C.
Suitable neutralizing agents for the process
according to the invention are set forth, for example,
in US-A-3,479,310.
Conversion of the isocyanate-terminated
prepolymers into aqueous dispersions is carried out by
10 known methods of polyurethane chemistry. When water is
added to the hydrophilic prepolymer, the organic
prepolymer is initially the continuous phase and there
is a marked rise in viscosity. As water continues to be
added, a phase reversal takes place and water becomes
15 the continuous phase and the viscosity falls. If
neutralizing agents are used in the water of dispersion,
a sufficient quantity of anionic groups must be present
in combination with the hydrophilic ethylene oxide units
during the phase reversal to form stable aqueous
20 dispersions. This may be achieved by adding the total
quantity of neutralizing agent to a proportion of the
water of dispersion which is not sufficient to lead to
phase reversal and then adding the remainder of the
water.
No marked increase in viscosity takes place if
the prepolymer is added to the water of dispersion. The
prepolymer is generally added with stirring in small
portions to the water of dispersion which may contain
neutralizing agent, optionally using mechanical mi~ing
30 apparatus in a continuous process. If low boiling
solvents have been used for the preparation of the
prepolymer, these may be removed before dispersion is
carried out but it is preferable to remove the solvent
after dispersion since the presence of solvent
35 facilitates the formation of the dispersion and chain
lengthening.
Mo-3095
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1 337445
If chain lengthening takes place in the aqueous
medium, the chain lengthening agent which contains amino
groups should be added before the free isocyanate groups
have undergone any marked reaction with water. Chain
5 lengthen;ng is generally carried out within 30 minuteæ,
preferably 15 minutes after the addition of water,
depending upon the temperature.
The amines used for chain lengthening of the
isocyanate-terminated prepolymers which are dispersed in
10 water may have average functionalities of from 2 to 6,
preferably from 2 to 4 and most preferably from 2 to 3,
the average functionality being the average number of
amino groups per molecule. The desired functionalities
may be obtained by mixing different amines.
Suitable amines are in particular hydrocarbons
having 2 to 6 amine groups contA;n;ng isocyanate-
reactive groups. The polyamines are generally aromatic,
aliphatic or alicyclic and contain 1 to 30 carbon atoms,
preferably 2 to 15 carbon atoms and most preferably 2 to
20 10 carbon atoms. These polyamines may also contain
other substituents, provided they are not isocyanate-
reactive groups. Examples of polyamines which are
suitable for the purpose of the present invention
include those previously mentioned as chain lengthening
25 agents and also diethylene triamine, triethylene
tetramine, tetraethylene pentAm;ne, pentaethylene
hex~m;ne, N,N,N-tris-(2-aminoethyl)amine,
N-(2-piperazinoethyl)-ethylene diamine, N,N'-bis-(2-
aminoethyl)-piperazine, N,N,N'-tris-(2-aminoethyl)-
30 ethylene diamine, N-[N-(2-aminoethyl)-2-aminoethyl]-
N'-(2-aminoethyl)-piperazine, N-(2-aminoethyl)-N'-(2-
piperazinoethyl)-ethylene ~;Am;ne, N,N-bis-(2-amino-
ethyl)-N-(2-piperazinoethyl)-amine, N,N-bis-(2-piper-
azinoethyl)-amine, polyethylene imines, imino-bis-
35 propylamine, guanidine, melamine, N-(2-aminoethyl)-
Mo-3095
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1 337445
-
1,3-propane-diamine, 3,3'-diamino-benzidine, 2,4,6-
triaminopyrimidine, polyoxypropylene amines, tetra-
propylene pentamine, tripropylenetetramine, N,N-bis-
(6-aminohexyl)amine, N,N'-bis-(3-aminopropyl)-ethylene
5 d~m;ne and 2,4-bis-(4'-aminobenzyl)-aniline. Preferred
polyamines include l-amino-3-aminomethyl-3,5,5-
trimethylcyclohexane (isophorone diamines or IPDA), bis-
(4-aminocyclohexyl)-methane, bis-(4-amino-3-methyl-
cyclohexyl)-methane, 1,6-~;~m;nohexane, ethylene
10 diamine, diethylene triamine, triethylene tetramine,
tetraethylene pentamine, N,N'-dimethyl-ethylene ~;~mine~
N-methyl-ethylene diamine and pentaethylene hexamine.
In addition to the above mentioned amines in
which all the isocyanate-reactive components are amine
15 groups, it is also suitable to use amines which contain
other nonionic isocyanate-reactive groups in addition to
the amine groups, e.g. ethanolamine, diethanolamine,
2-amino-2-hydroxymethyl-1,3-propane diol or N-(2-amino-
ethyl)-ethanolamine.
The quantity of polyamine to be used depends on
the terminal isocyanate group content of the prepolymer.
The ratio of milliequivalents of isocyanate end groups
in the prepolymer to amino groups in the polyfunctional
amine is generally in the range of about 1.0:0.20 to
25 about 1.0:1.1, preferably about 1.0:0.3 to 1.0:0.98.
The reaction between isocyanate end groups and
polyamines is carried out at temperatures of about 5 to
90C, preferably about 20 to 80C. The polyamine may be
added to the dispersion of prepolymer in water either as
30 the pure substance or diluted with water or suitable
organic solvents such as those already described above
for the preparation of the prepolymer.
The polyurethane dispersions prepared by the
process described above may be modified with isocyanates
35 after formation of the dispersion, as described in DOS
2,708,442.
Mo-3095
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1 337445
Polyisocyanate compounds containing at least two
free isocyanate groups may be added to the solutions and
dispersions according to the invention before use.
Polyisocyanate compounds which can be emulsified
in water are particularly preferred. These include, for
example, the compounds described in EP 206,059 and DE-OS
3,112,117 (which correspond to US Patents 4,663,377 and
4,433,095, respectively. The polyisocyanate compounds
are put into the process in a quantity of about 0.1 to
20% by weight, preferably about 0.5 to 10% by weight,
most preferably about 1.5 to 6% by weight, based on the
solution or dispersion. This addition results in a
considerable improvement in the heat strength of adhesive
bonds which have been prepared from the solutions or
dispersions according to the invention.
The product finally obtained is a stable,
aqueous polyurethane dispersion having a solids content
of up to about 60% by weight, most preferably about 25 to
50% by weight. The dispersions may be further diluted in
20 any proportion. The particle diameter is generally below
1 ~m, preferably about 0.001 to 0.5 ~m. The average
particle diameter should be below 0.5 ~m, preferably
about 0.01 to 0.3 ~m.
When the hydrophilic group content is very low,
25 average particle diameters of about 5 ~m to 50 ~m may be
obtained. Such dispersions are of interest, for example,
for the preparation of polyurethane powders.
The dispersions may be blended with other
dispersions, e.g. with polyvinyl acetate or with
30 dispersions of polyethylene, polystyrene, polybutadiene,
polyvinyl chloride, polyacrylate or copolymer plastics
dispersions. Known emulsifiers which are not chemically
fixed, particularly ionic emulsifiers, may also be added
but are, of course, not necessary.
MD 3095 - 21 -
1 337~45
-
Fillers, plasticizers, pigments, carbon black
and silica sols and dispersions of aluminium, clay or
asbestos may also be incorporated in the dispersions.
The dispersions of the polyurethane
5 compositions in water are in most cases stable and
suitable for storage and transport and may be worked up
at any later date, e.g. by a molding or shaping process.
They generally dry directly to form dimensionally stable
plastic coatings but the products of the process may
10 also be given their final form in the presence of known
cross-l;nk;ng agents. The polyurethanes obtained vary
in their properties according to the selected chemical
composition and the urethane group content. Thus soft,
sticky masses and thermoplastic and rubbery elastic
15 properties may be obtained over a wide range of hardness
up to glass hard duroplasts. The hydrophilic character
of the products may also vary within certain limits.
The elastic products may be processed thermoplastically
at elevated temperatures, for example at about 100 to
20 180C, if they have not been chemically cross-linked.
The products of the process are suitable for
coating and impregnating woven and non-woven textiles,
leather, paper, wood, metals, ceramics, stone, concrete,
bitumen, hard fibers, straw, glass, porcelain, plastics
25 of a variety of different types, glass fibers for
antistatic and crease resistant finishes; as binders for
non-woven, adhesives, a & esion promotors, laminating
agents, hydrophobicizing agents, plasticizers and
binders, e.g. for cork powder or sawdust, glass fibers,
30 asbestos, paper-like materials, plastics or rubber waste
and ceramic materials; as auxiliary agents in textile
printing and in the paper industry; as additives for
polymers; as sizing agents, for example for glass
fibers; and for finishing leather.
Mo-3095
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1 337445
-
The products are preferably applied as
dispersions or pastes to a porous support which
subsequently remains joined to the finished product,
e.g. woven or non-woven textiles or fiber mats, felts or
5 fleeces; also paper fleeces, foam films or split leather
which produce instant solidification of the coating due
to their suction effect. The product is subsequently
dried at an elevated temperature and optionally pressed.
Drying may also be carried out on smooth, porous or
10 non-porous materials such as metals, glass, paper,
cardboard, ceramic materials, sheet steel, silicone
rubber or aluminium foil. The sheet-like structure
obtained is subsequently lifted off and used as such or
applied to a substrate by gluing, flame laminating or
15 calandering, employing the reversal process.
Application by the reversal process may be carried out
at any time.
The properties of the products of this process
may be modified by using vinyl polymers or active or
20 inactive fillers. The following, for example, may be
used: polyethylene, polypropylene, polyvinyl acetate,
ethylene/vinyl acetate copolymers which are optionally
(partly) saponified and/or grafted with vinyl chloride,
styrene/butadiene copolymers, ethylene (graft)
25 copolymers, polyacrylates, carbon black, silica,
asbestos, talcum, kaolin, titanium dioxide, glass
powder, or glass in the form of fibers~ and cellulose.
The end product may contain up to about 70Z of such
fillers, based on the total dry substance content,
30 depending on the required properties and the purpose for
which the products are to be used.
Dyes, pigments, plasticizers and additives
which influence the flow properties may, of course, also
be added.
Mo-3095
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1 337445
__
Drying of the products may be carried out at
room temperature or elevated temperature. The drying
temperature to be chosen in any given case depends not
only on the chemical composition of the material but
5 also on the moisture content, the drying time and the
thickness of the layer and is easily determined by a
prel;m;n~ry test. At the given heating time, the drying
temperature must always be below the solidification
temperature.
The sheet structures may subsequently be
covered with a finish to increase the resistance of
their surface. Aqueous dispersions or solutions are
also preferably used for this purpose.
Very hard polyurethanes obtained from finely
15 divided dispersions and sols are suitable for use as
stoving lacquers and in some cases even as air drying
lacquers. They combine great hardness and elasticity
with a high gloss and, when used with aliphatic
diisocyanates, have good light resistance and weather
20 resistance.
The examples given below serve to illustrate
the composition and preparation and some of the physical
properties of the products.
The parts given in the examples are parts by
25 weight. Two criteria are employed for assessing the
quality of the dispersions:
1. Particle size from dynamic light scattering
2. Stability to centrifuging (15 minutes at
4500 revs per min). The assessment ranges
from 1 (no formation of sediment) to 6
(completely sedimented).
EXAMPLES
Example 1
In the first step of preparation of the
35 prepolymer, 80 parts of a propoxylated adduct of
Mo-3095
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1 337445
_~
2-butene diol-(1,4) and NaHSO3 (molecular weight 430) in
the form of a 70Z solution in toluene (diol sulphonate)
were reacted with 88.6 parts of isophorone diisocyanate
(IPDI) and 33.6 parts of hexAmethylene diisocyanate
5 (HDI) at 90C within 1.6 hours. A reaction product
having an isocyanate content of l9.lZ was obtained.
In the second step of preparation of the
prepolymer, 116.7 parts of the reaction product from the
first reaction step were reacted with 400 parts of a
10 previously dehydrated polyester of adipic acid and
butane diol-(1,4) (molecular weight 2250) for 2 hours at
100C. A constant NCO value of 2.6Z was established.
The prepolymer was then cooled to 70C.
453 parts of the prepolymer, which had been
15 prepared by a multi-stage process, were dispersed in 600
parts of water (heated to 50C) with vigorous stirring.
A solution of 6.0 parts of ethylene diamine in 100 parts
of water was added as chain lengthening agent over a
period of 5 minutes at 50C and the reaction mixture was
20 then stirred for about 2 hours.
A finely divided dispersion having a solids
content of 43.4Z by weight and a viscosity of 280 cP was
obtained. The content of SOe3 groups was 1.5Z by
weight, based on the solids content. The particle size
25 was 185 nm and the stability to centrifuging was 1.
Example 2 (comparison example to Example 1)
A prepolymer having the same composition as in
Example 1 was prepared from the same stirring components
by reacting the polyester, the diol sulphonate, IPDI and
30 HDI together in a single step at 100C. A constant NCO
value of 2.9Z was established. The prepolymer was then
cooled to 70C.
490 parts of the prepolymer which had been
prepared in a single stage were dispersed in 600 parts
35 of water (50C) with vigorous stirring. A solution of
Mo-3095
-25-
1 337445
7.0 parts of ethylene diAmine in 150 parts of water was
added over a period of 5 minutes at 50C for chain
lengthening and the reaction mixture was then stirred
for about 2 hours.
No stable dispersion was obtained under these
conditions.
Example 3
In the first step of preparation of the
prepolymer, 50 parts of the diol sulphonate from Example
10 1 were reacted with 145 parts of dicyclohexyl
methane-4,4'-diisocyanate in 32.5 parts of N-methyl-
pyrrolidone (NMP) within 1 hour at 90C. A reaction
product having an isocyanate content of 16.7% was
obtained.
In the second step of preparation of the
prepolymer, 194 parts of the reaction product from the
first reaction step were reacted at 100 to 120C for
5 hours with 400 parts of a previously dehydrated adipic
acid/butane diol-(1,4) polyester (molecular weight
20 2250), 28 parts of a polyethylene oxide/polypropylene
oxide polyether started on n-butanol (molecular weight
2145; molar ratio ethylene oxide: propylene oxide 83:17)
and 16 parts of a propylene oxide ether (OH number 197)
which has been started on bisphenol A. A constant NCO
25 value of 2.lZ was established. The prepolymer was then
cooled to 70C.
545 parts of this prepolymer, which had been
prepared by a multi-stage process, were dispersed in
600 parts of water (35C) with vigorous stirring. A
30 solution of 5.9 parts of ethylene ~;Amine in 220 parts
of water was added over a period of 5 minutes at 50C
for chain lengthening and the reaction mixture was then
stirred for 2 houræ.
A finely divided diæpersion having a solids
35 content of 37.8Z by weight and a viscosity of 23.4 cP
Mo-3095
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1 337445
~_ e
was obtained. The SO 3 group content was O.9Z by
weight, based on the solids content. The particle size
was 208 nm and the stability to centrifuging was 2.
Example 4 (comparison example to Example 3)
A prepolymer having the same composition as in
Example 3 was prepared from the same starting components
by reacting the polyester, the diol sulphonate, the
diisocyanate and the two polyethers together in one step
at 100C. A constant NCO value of 2.1% was established.
10 The prepolymer was then cooled to 70C.
527 parts of the prepolymer which had been
prepared in a single stage were dispersed in 600 parts
of water (35C) with vigorous stirring. A solution of
5.5 parts of ethylene diamine in 200 parts of water was
15 added over a period of 5 minutes at 50C for chain
lengthening and the reaction mixture was then stirred
for about 2 hours.
A coarse dispersion having a solids content of
38.5~ by weight and a viscosity of 14 cP was obtained.
20 The SOe3 group content was 0.9~ by weight, based on the
solids content. The particle size was 268 nm and the
stability to centrifuging was 3 to 4.
Example 5
In the first step of preparation of the
25 prepolymer, 43 parts of the diol sulphonate from
Example 1 in 27.8 parts of N-methylpyrrolidone were
added dropwise to 87.7 parts of toluylene diisocyanate
(2,4:2,6 isomeric ratio 80:20) and 0.4 parts of
p-toluene sulphonic acid at a reaction temperature of
30 50C.
A reaction product having an isocyanate content
of 22.3~ was obtained.
In the second step of preparation of the
prepolymer, 137 parts of the reaction product from the
35 first reaction step were reacted at 80C for 2 hours
Mo-3095
-27-
__ 1 3 3 7 4 4 ~
with 400 parts of a previously dehydrated polyester of
adipic acid and butane diol-(1,4) (molecular weight
2250), 28 parts of a polyethylene oxide/polypropylene
oxide polyether started on n-butanol (molecular weight
5 2145; molar ratio ethylene oxide:propylene oxide 83:17)
and 16 parts of a propylene oxide ether (OH number 197)
which has been started on bisphenol A. A constant
isocyanate value of 1.8Z was established. The
prepolymer was then cooled to 70C.
513 parts of this prepolymer which had been
prepared by a multi-stage process were dispersed in 600
parts of water (38C) with vigorous stirring. A
solution of 4.7 parts of ethylene diamine in 150 parts
of water were added over a period of 5 minutes at 50C
15 for chain lengthening and the reaction mixture was then
stirred for about 2 hours.
A finely divided dispersion having a solids
content of 41.9Z by weight and a viscosity of 84 cP was
obtained. The SOe3 group content was 0.8Z by weight,
20 based on the solids content. The particle size was 194
nm and the stability to centrifuging was 1.
Example 6 (comparison example to Example 5)
A prepolymer having the same composition as in
Example 5 was prepared from the same starting components
25 by reacting the polyester, the diol sulphonate, the
diisocyanate and the two polyethers together in one step
at 100C. A constant NCO value of 1.6~ was established.
The prepolymer was then cooled to 70C.
500 parts of this prepolymer prepared by the
30 single stage process were dispersed in 600 parts of
water (35C) with vigorous stirring. A solution of 3.9
parts of ethylene ~;~mine in 150 parts of water was
added over a period of 5 minutes at 50C for chain
lengthe~ng and the reaction mixture was then stirred
35 for about 2 hours.
Mo-3095
-28-
1 33, 44~
A coarse dispersion having a solids content of
38.8Z by weight was obtained. The SOe3 group content
was 0.8% by weight, based on the solids content. The
particle size was 294 nm and the stability to
5 centrifuging was 5 to 6.
Example 7
In the first step of preparation of the
prepolymer, 43 parts of the diol sulphonate from
Example 1 in 74.5 parts of isophorone diisocyanate and
10 28.2 parts of he~Amethylene diisocyanate were reacted
together at a reaction temperature of 80C. A reaction
product having an isocyanate content of 24.8Z was
obtained.
In the second step of preparation of the
15 prepolymer, 119 parts of the reaction product from the
first reaction step were reacted for 3 hours at 95C
with 400 parts of a previously dehydrated polyester of
adipic acid and butane diol-(1,4) (molecular weight
2250), 28 parts of a polyethylene oxide/polypropylene
20 oxide polyether started on n-butanol (molecular weight
2145; molar ratio ethylene oxide:propylene oxide 83:17)
and 16 parts of a propylene oxide ether (OH number 197)
which had been started on bisphenol A. A constant NCO
value of 1.5Z was established. The prepolymer was then
25 cooled to 70C.
500 parts of this prepolymer prepared by a
multi-stage process were dispersed in 600 parts of water
(50C) with vigorous stirring. A solution of 3.7 parts
of ethylene ~i~m;ne in 150 parts of water was added over
30 a period of 5 minutes at 50C for chain lengthening and
the reaction mixture was then stirred for about 2 hours.
A finely divided dispersion having a solids
content of 40.8Z by weight and a viscosity of 1122 cP
was obtained. The SOe3 group content was 0.8~ by
35 weight, based on the solids content. The particle size
was 136 nm and the stability to centrifuging was 1.
Mo-3095
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1 337445
_ _
Example 8 (comparison example to Example 7)
A prepolymer having the same composition as in
Example 7 was prepared from the ssme starting components
by reacting the polyester, the diol sulphonate, the
5 diisocyanates and the two polyethers together in one
step at 95C. A constant NCO value of 1.7~ was
established. The prepolymer was then cooled to 70C.
500 parts of this prepolymer prepared by a
single stage process were dispersed in 650 parts of
10 water (50C) with vigorous stirring. A solution of
4.2 parts of ethylene ~;Am;ne in 100 parts of water was
added over a period of 5 minutes at 50C for chain
lengthening and the reaction mixture was then stirred
for about 2 hours.
A coarse dispersion having a solids content of
41~ by weight and a viscosity of 91 cP was obtained.
The SOe3 group content was 0.8% by weight, based on the
solids content. The particle size was 184 nm and the
stability to centrifuging was 1 to 2.
20 Example 9
In the first step of preparation of the
prepolymer, 92.5 parts of the diol sulphonate from
Example 1 were reacted with 157.5 parts of isophorone
diisocyanate at a reaction temperature of 100C. A
25 reaction product having an isocyanate content of 18.7
was obtained.
In the second stage of preparation of the
prepolymer, 203 parts of the reaction product from the
first reaction step were reacted at 100C for 4 hours
30 with 400 parts of a previously dehydrated polyester of
adipic acid and butane diol-(1,4) (molecular weight
2250), 28 parts of a polyethylene oxide/polypropylene
oxide polyether started on n-butanol (molecular weight
2145; molar ratio ethylene oxide: propylene oxide 83:17)
35 snd 16 parts of a propylene oxide ether (OH number 197)
Mo-3095
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1 337445
which had been started on bisphenol A. A constant NCO
value of 3.2Z was established. The prepolymer was then
cooled to 70C.
545 parts of this prepolymer prepared by a
5 multi-stage process were dispersed in 600 parts of water
(50C) with vigorous stirring. A solution of 8.7 parts
of ethylene diamine in 100 parts of water were added
over a period of 5 minutes at 50C for chain lengthening
and the reaction mixture was then stirred for about 2
10 hours.
A finely divided dispersion having a solids
content of 45.6Z by weight was obtained. The SOe3 group
content was 1.5Z by weight, based on the solids content.
The particle size was 87 nm and the stability to
15 centrifuging was 1.
Example 10 (comparison example to Example 9)
A prepolymer having the same composition as in
Example 9 was prepared from the same starting components
by reacting the polyester, the diol sulphonate, the
20 diisocyanate and the two polyethers together in one step
at 110C. A constant NCO value of 3.2Z was established.
The prepolymer was then cooled to 70C.
580 parts of this prepolymer prepared in a
single stage were dispersed in 650 parts of water (50C)
25 with vigorous stirring. A solution of 9.2 parts of
ethylene diamine in 220 parts of water was added over a
period of 5 minutes at 50C for chain lengthening and
the reaction mixture was then stirred for about 2 hours.
A coarse dispersion having a solids content of
30 42Z by weight was obtained. The SOe3 group content was
1.5Z by weight, based on the solids content. The
particle size was 138 nm and the stability to
centrifuging was 1.
Mo-3095
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1 337445
Example 11
In the first step of preparation of the
prepolymer, 70 parts of the diol sulphonate from
Example 1 were reacted with 190 parts of isophorone
5 diisocyanate for 4 hours at a reaction temperature of
120C. A reaction product having an isocyanate content
of 24.2Z was obtained.
In the second step of preparation of the
prepolymer, 209 parts of the reaction product from the
10 first reaction step were reacted at 100C for 3 hours
with 400 parts of a previously dehydrated polyester of
adipic acid and butane diol-(1,4) (molecular weight
2250) and 12 parts of butane diol-(1,4). A constant NCO
value of 3.8% was established. The prepolymer was then
15 cooled to 70C.
540 parts of this prepolymer prepared by a
multi-stage process were dispersed in 600 parts of water
(50C) with vigorous stirring. A solution of 10.2 parts
of ethylene diamine in 150 parts of water was added over
20 a period of 5 minutes at 50C for chain lengthening and
the reaction mixture was then stirred for about 2 hours.
A finely divided dispersion having a solids
content of 41.6Z by weight was obtained. The SOe3 group
content was 1.2Z by weight, based on the solids content.
25 The particle size was 104 nm and the stability to
centrifuging was 1.
Example 12 (comparison example to Example 11)
A prepolymer having the same composition as in
Example 11 was prepared from the same starting
30 components by reacting the polyester, the diol
sulphonate, the diisocyanate and butane diol-(1,4)
together in one step at 110C. A constant NCO value of
4.0Z was established. The prepolymer was then cooled to
70C.
Mo-3095
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1 337445
534 parts of this prepolymer prepared by a
single stage process were dispersed in 650 parts of
water (50C) with vigorous stirring. A solution of 10.6
parts of ethylene ~iA~ine in 150 parts of water was
5 added over a period of 5 minutes at 50C for chain
lengthening and the reaction mixture was then stirred
for about 2 hours.
A coarse dispersion having a solids content of
43.7~ by weight was obtained. The SOe3 group content
10 was 1.2~ by weight, based on the solids content. The
particle size was 217 nm and the stability to
centrifuging was 2.
Example 13
In the first step of preparation of the
15 prepolymer, 45 parts of the diol sulphonate from
Example 1 were reacted with 116.7 parts of isophorone
diisocyanate and 37.9 parts of hexamethylene
diisocyanate for 1.5 hours at a reaction temperature of
90C. A reaction product having an isocyanate content
20 of 28.5~ was obtained.
In the second step of preparation of the
prepolymer, 160 parts of the reaction product from the
first reaction step were reacted at 100C for 4 hours
with 400 parts of a previously dehydrated polyester of
25 adipic acid/hexane diol-(1,6)/neopentyl glycol (ratio of
glycols 65:35, molecular weight 1700) and 28 parts of a
polyethylene oxide/polypropylene oxide polyester started
on n-butanol (molecular weight 2145; molar ratio of
ethylene oxide to propylene oxide 83:17). A constant
30 NCO value of 4.1Z was established. The prepolymer was
then cooled to 70C.
520 parts of this prepolymer prepared by a
multi-stage process were dispersed in 600 parts of water
(50C) with vigorous stirring. A solution of 32.8 parts
35 of isophorone diamine in 180 parts of water was added
Mo-3095
-33-
1 337445
over a period of 5 minutes at 50C for chain lengthening
and the reaction mixture was then stirred for about 2
hours.
A finely divided dispersion having a solids
5 content of 45Z by weight and a viscosity of 60 cP was
obtained. The SOe3 group content was 0.8a by weight,
based on the solids content. The particle size was
259 nm and the stability to centrifuging was 1.
Example 14 (comparison example to Example 13)
A prepolymer having the same composition as in
Example 13 was prepared from the same starting
components by reacting the polyester, the diol
sulphonate, the diisocyanate and the polyether together
in one step at 95C. A constant NCO value of 4.lZ was
15 established. The prepolymer was then cooled to 70C.
515 parts of this prepolymer prepared by a
single stage process were dispersed in 600 parts of
water (50C) with vigorous stirring. A solution of 32
parts of isophorone diamine in 180 parts of water was
20 added over a period of 5 minutes at 50C for chain
lengthening and the reaction mixture was then stirred
for about 2 hours.
A coarse dispersion having a solids content of
42.82 by weight was obtained. The SOe3 group content
25 was 0.8% by weight, based on the solids content. The
particle size was 325 nm and the stability to
centrifuging was 2.
Although the invention has been described in
detail in the foregoing for the purpose of illustration,
30 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.
Mo-3095
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1 337445
~_~ PROCESS FOR THE PREPARATION OF AQUEOUS
POLYURETHANE-POLYUREA DISPERSIONS
SUPPLEMENTARY DISCLOSURE
This is a Supplementary Disclosure to Canadian Patent
Application,Serial No. 580,641, filed October 19, 1988.
In accordance with the present invention at least
50%, preferably at least 65%, more preferably at least 80% and
most preferably 100% of the isocyanate-reactive groups of
component bl) are reacted with the polyisocyanate before the
addition of component b2) and optional component b3).
Mo-3095-Ca ~ ~ ~
