Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
2 IL) ~ rj
Mo-3851
L~A 28894-US
COATING COMPOSITIONS, A PROCESS FOR THEIR PRODUCTION
AND ~HEIR USE FOR COATING WATER-_ESISTANT SUBSTRATES
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a new aqueous coating
composition containing a cationically modified polyol component
dissslved and/or dispersed in water, optionally a reactive
diluent and, emulsified therein~ a polyisocyanate component; a
process for the production of this coating composition; and its
use for the production of coatings on water-resistant
substrates.
Description of the Prior Art
Aqueous coating compositiors are gaining increasing
importance for economic and ecological reasons. However, the
replacement of conventional~ solvent-based coating compositions
is proceeding more slowly than expected.
There are numerous reasons for this. Aqueous dispersions
frequently still have processing disadvantages when compared to
coating compositions dissolved in organic media. With aqueous
solut;ons there is also the conflict between providing
sufficient water dispersibility or solubility versus the
contrary effect resulting therefrom of the lower resistance of
the coatings to water. This is not a problem with coating
compositions dissolved in organic solvents. In addition, there
are also process;ng problems in this regard which result from
the high viscosity of the aqueous coating compositions. These
problems have previously been overcome by the use of organic
auxiliary solvents. However, the amount of auxiliary solvent
used in this conneotion is limited, since, otherwise, the
ecological impact of the aqueous systems is lessened.
L~ 28 ~94-~S
2 ~
For this reason, in binder systems crosslinked with
melamine resins ~U~ Patents 4 031 052, 4 171 294 and 4 276 210
and DE-OS 2 446 760 and 2 847 532), water-dilutable reactive
diluents have previously been used. These resins have a
favorable effect on the solubility properties of the polymer
systems and are also incorporated ;n the coatings by melamine
resin crosslinking. However, the reactivity of many aqueous
melamine resins is so low that high crosslinking temperatures
are requ;red such that the reactive diluents can escape from
the coatings before crosslinking occurs.
Only recently have aqueous two-component polyurethane
systems become known (DE-OS 3 829 587). In these systems the
binder is based on a polyacrylate resin dissolved or dispersedin water in combination with a polyisocyanate containing free
isocyanate groups emulsified in this dispersion or solution.
The systems are essentially solvent-freP, as is evident from
the fact that the solvents used in the production of these
polymer resins are removed before preparation of the aqueous
composition. These known prior art systems may be used to
produce high-grade coatings, which are comparable in their
properties to coatings prepared from solvent-containing coating
compositions of analogous structure.
It has now surprisingly been found that aqueous
two-component polyurethane coating compositions in which the
polyol co~ponent is cationically as opposed to anionically
modified have a considerably longer pot life and are as
suitable as analogous systems based on anionically modified
polyhydroxyl compounds for the production of high-grade
coatings. The coating compositions according to the invention,
which are described in more detail below, have pot lives of at
least 8 hours to as much as several days.
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SUMMARY OF THE INVENTION
The present inventlon relates to an aqueous two-component
coating composition wherein the binder contains
a) a component which is dissolved and/or dispersed in water,
has an average hydroxyl number of 15 to 200 mg KOH/g and
contains
al) a polyol component having a content of 8 to 450
milliequival~nts, per 100 9 of component al) solids,
of chemically incorporated ammonium groups, =N=+ and
containing one or more polyaddit;on, polymerization
and/or polycondensation resins which are
water-dilutable, contain hydroxyl groups and have a
molecular weight (Mn) of at least 500 and
: a2) up to 10 wt%, based on the weight of component al),
of one or more reactive diluents which are
water-soluble, have a molecular weight ~Mn) below 500
;~ and contain at least one isocyanate-reactive group,
and
b) a polyisocyanate component having an NCO content of 5 to
25 wt~o and containing one or polyisocyanates which are
: 20 emulsified in the aqueous solution andfor dispersion of
hydroxyl group-containing component a),
~:~ wherein components a) and b) are present in an amount
sufficient to provide an equivalent ratio of isocyanate groups
of component b) to isocyanate-reactive groups of component a)
~f 0.5:1 to 5:1.
The present invention also relates to a process for the
production of this coating composition and to their use for the
production of coatings on water-resistant substrates.
; UETATLED DESCRIPTIOW OF T~IE INVENTION
Component a) has an average hydroxyl number of 15 to 200,
preferably 40 to 160, mg KOH/g and preferably an average
hydroxyl functional~ty of at least 2.5, more preferably at
least 3. It contains of polyol component al) which has a
molecular weiyht (Mn) greater than 500 or a mixture of polyol
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.:
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component al) with up to 10 wt%, based on the weight of al), of
a water-soluble reactlve diluent which has a molecular weight
(Mn) below 500 and at least one group reactive towards
isocyanate groups.
The aqueous solutions and/or dispersions of component a)
preferably contain 65 to 400, more preferably 100 to 240, parts
by weight of water per 100 parts by weight of component a).
Polyol component al) is selected from hydroxyl
group-containing polyaddition, polycondensation and/or
polymerization resins having a molecular weight (Mn) of at
least 500, preferably 1500 to 5000; and a hydroxyl
functionality of at least 2, preferably at least 3. Component
a) contains at least a portion and preferably exclusively
contains polyol components al) which have a content of
incorporated ammonium groups, =N=++, which is sufficient to
solubilize or disperse component al) in water. It is possible,
although not generally preferred, to use mixtures of
polyhydroxyl compounds which contain both cationically modified
polyols and also ionically unmodified polyols, provided that
the proportion of the cationically modified polyols is
sufficient to ensure the dispersibility or the solubility of
the total mixture. The content of chemically incorporated
ammonium groups, =N=+, in polyol component al) is 8 to 450,
- preferably 25 to 250, milliequivalents per 100 9 of solids.
Molecular weights (Mn) of less than 5000 are measured by
vapor-pressure osmometry in dioxane and acetone, the low value
being used when the values differed. Molecular weights (Mn) of
greater than 5000 are determined by membrane osmometry in
acetone.
The polyhydroxyl compounds of component al) may be
catlonlcally modified by the incorporation of tertiary nitrogen
atoms and their subsequent conversion to an ammonium grollp by
neutralization with an acid or by quaternization with a
quaterniziny agent.
Mo3851
1 S
Polyhydroxyl compounds suitable as component al) include
polyaddition, polycondensation and/or polymerization products
that satisfy the above requirements. These compounds often
contain segments which have been formed by a polyaddition
reaction in add;tion to segments which have been for~ed by a
polycondensat;on reaction or a polymerization reaction.
Examples of compounds which can be used as component al)
or as a part of component al3 or which can be converted by
neutralization or quaternization into these compounds include:
i) Polyether polyols having incorporated tertiary
nitrogen atoms which can be produced by the propoxylation
and/or ethoxylation of starter molecules having amine nitrogen.
Such polyether polyols include the propoxylation and/or
ethoxylation products of ammonia, ethanolamine,
tr;ethanolamine, ethylenediamine and mixtures of these amines.
ii) Polyester or polyamide resins ha~ing ter~iary
nitrogen atoms wh;ch are prepared by the polycondensation of
multivalent and optionally monovalent starting components.
Known processes for the polycondensation of alcohols and
carboxylic acids are described, e.g., in Rompp's Chemielexikon,
vol. 1~ page 202, Frankh'sche Verlagsbuchhandlung, Stuttgart,
1966, and D.H. Solomon, The Chemistry of Organic Filmformers,
pp. 75-101, John Wiley ~ Sons Inc., New York, 1967.
Starting materials for preparing the polycondensation
resins include
- alcohols having 1 to 6, preferably 2 to 4 hydroxyl groups
and a molecular weight of 32 to 500, preferably 62 to 250, such
as ethylene glycol, propylene glycol, butanediols, neopentyl
glycols, cyclohexanedimethanols, 2-ethyl-1,3-propanediol,
hexanediols, ether alcohols such as di- and triethylene
glycols, ethoxylated bisphenols, perhydrogenated bisphenols,
trimethylolekhane, trimethylolpropane, glycerol,
pentaerythritol, dipentaerythritol, mannitol and sorbitol; and
monohydric chain-termlnating alcohols such as methanol,
propanol, butanol, cyclohexanol and benzyl alcohol;
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- multivalent carboxylic acids or carboxylic acid anhydrides
having a molecular weigh~ of 100 to 300, such as phthalic acid,
phthalic anhydride, isophthalic acid, terephthalic acid,
tetrahydrophthalic acid, hexahydrophthalic acid, ~rimellitic
s anhydride, pyromellitic anhydride, maleic anhydride, adipic
acid and succinic anhydride;
- aromatic or saturated aliphatic monocarboxylic acids such
as benzoic acid, hexahydrobenzoic acid, butylbenzoic acid,
coconut oil acids and ~ ethylhexanoic acid;
}o - olefinically unsaturated fatty acids and derivatives of
olefinically unsaturated fatty acids such as the fatty acids of
linseed oil, soya oil, tung oil, safflower oil, dehydrated
castor oil, cottonseed oil, groundnut oil and tall oil;
synthetic olefinlcally unsaturated C12 - C22fatty acids; and
derivatives obtained by conjugation~ isomerization or
dimerization of these unsaturated fatty acids;
- the oils corresponding to the previously mentioned natural
fatty acids such as linseed oil, soya oil, tung oil, safflower
oil, dehydrated castor oil, cottonseed oil, groundnut oil, tall
oil and castor oil; and
; - amines and/or alcohols having tertiar~y nitrogen atoms such
: as N-methyldiethanolamine, N-methyldipropanolamine,
N-butyldiethanolamine, N-butyldipropanolamine,
N-stearyldiethanolamine, N-stearyldipropanolamine,
triethanolamine, tripropanolamine, hydroxyethylmorpholine,
2-hydro~ypropylmorpholine, hydroxyethylpiperazine,
2-hydroxypropylpiperazine and alkoxylation productsofallthese
amines and/or alcohols having a molecular weight ~Mn) of less
than 3000.
iii) Polyols having urethane groups and tertiary nitroyen
atoms which may be obtained in known manner from the
conventional starting materials of polyurethane chemistry.
These polyurethanes may be prepared by reacting less than
stoichiometric amounts of polyisocyanates with the previously
mentioned, preferably at least difunctional, 10w molecular
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weight, starting components having ~ertiary nitrogen atoms and
groups reactive towards isocyanate groups; polyester polyols
having a molecular weight (Mn) of ?50 to 10,000, preferably
1000 to 5000, which may or may not contain ;ncorporated
tertiary nitrogen atoms; polyether polyols having a molecular
weight (Mn) of 250 to 10,000, preferably 1000 to 5000, which
may or may not contain incorporated tertiary nitrogen atoms;
the previously mentioned polyhydric alcohols having a molecular
weight of 62 to 250; and mixtures of these polyhydroxyl
compounds. The nature and proportions of the reactants are
chosen so that the urethane-modified polyhydroxyl compounds
obtained satisfy the conditions previously set forth with
regard to the content of tertiary nitrogen atoms, molecular
weight and OH number.
Suitable polyisocyanates for the production of these
resins include hexamethylene diisocyanate, isophorone
diisocyanate, 4~4'-diisocyanatodicyclohexylmethane, 2,4 -
and/or 2,6-diisocyanatotoluene and/or the isomeric or
homologous polyisocyanates or polyisocyanate mixtures of the
diphenylmethane series.
iv) Polyhydroxypolyacrylates prepared by the known
copolymerization of olefinically unsaturated monomers wherein a
portion of these ~onomers have alcoholic hydroxyl groups and a
portion have tertiary nitrogen atoms incorporated therein.
Suitable monomers for the production of these polyacrylate
resins include Cl-C8, preferably Cl-C2-alkyl methacrylates such
as methyl or ethyl methacrylate; styrene; Cl-C8-alkyl acrylates
such as methyl, ethyl, n-propyl, isopropyl, n-butyl, n-hexyl or
n-octyl âcrylate; C2 C8-hydroxyalkyl (meth)acrylates such as
hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate
(e.g., an isomer mixture obtained by the addition of propylene
oxide to (meth)acrylic acid), 4-hydroxybutyl (meth)acrylate and
mixtures of such monomers; vinyltoluenes; vinyl esters such as
vinyl acetate; and monomers having tert-nitrogen atoms, e.g.,
such as the acrylate or methacrylate esters of alcohols having
Mo3851
2~g~S
tertiary nitrogen atoms, such as N,N-dimethylam;noethanol, and
N-(2-hydroxyethyl)-morpholine or -p;perid;ne.
It is also possible to produee polyacrylate polyols having
tertiary nitrogen atoms by the incorporation of the pneviously
disclosed alcohols having ter~iary nitrogen atoms via urethane
groups. This is accomplished by reacting a portion of the
hydroxyl groups of a polyacrylate polyol with tertiary
nitrogen-containing isocyanatourethanes. These
isocyanatourethanes may be produced, for example, by reacting
monohydric alcohols having tertiary nitrogen atoms with a large
excess of diisocyanate and subsequently removing the unreacted
excess diisocyanate by distillation.
Component al) may contain mixtures of the previously
descr;bed polyhydroxyl compounds provided that the mixtures
contain the required content of ammonium groups. The
incorporated tertiary nitrogen atoms are converted into
ammonium ions by neutralization or quaternization.
To achieve at least partial neutralization ~protonation),
the incorporated basic tertiary nitrogen atoms are treated with
aliphatic acids such as formic acid, acetic acld, propionic
acid, lactic acid, malonir acid, malic acid7 tartaric acid,
glyoxalic acid, methanesulphonic acid, oxalic acid, fumaric
acid, succinic acid and adipic acid. These acids can be used
as aqueous solution or anhydrous (e.g., methanesulphonic acid).
The neutralization may be carried out in bulk, in aqueous
medium or in the inorganic phase. To produce an aqueous
solution or dispersion of component al), it is often sufficient
to mix the polyhydroxyl compounds having tertiary nitrogen
atoms with an aqueous solution of an acid suitable for
3~ neutral katlon. lf it is desired to produce anhydrous
polyhydroxyl compounds, then neutralization with an anhydrous
acid such as methanesulphonic acid is preferrecl. In this way
an anhydrous salt is formed which can later be dissolved c~r
dispersed by simple stirring with water.
Mo3851
~ 3
The use of water-miscible solvents, such as acetone,
during neutralization is also poss;ble. In particular, acetone
solut~ons of the at least partly neutralized polyhydroxyl
compounds can simply be stirred with water and, if desired, the
acetone can be removed by dlst~llat~on.
Suitable alkylating agents are known and include methyl
chloride, methyl bromide, methyl iodide, dimethyl sulphate,
diethyl sulphate, methyl p-toluenesulphonate and
chloroacetamide. The alkylation reactlon can be carried out,
for example, in the presence of solvents, such as acetone,
acetonitrile, tert-butanol or ethyl acetate, at 20 to 100C
with subsequent removal of solvent. The alkylation san also
advantageously be carried out in the presence of small amounts
of polar, high-boiling solvents, for example, N-methyl
pyrrolidone and the acetates of propylene glycol and glycerol
as well as propyleneglycol-n-buty]etheracetate and propyleneglycol-methyletheracetate.
These solvents are not removed and serve as coalescing agents
during the subsequent formation of coatings.
Optional polyol component a2), i.e., the reac~ive diluent,
is selected from compounds which contain at least one,
preferably 2 to 4, isocyanate-reactiv~ groups, are
water-soluble and have a molecular weight (Mn) of less than
500, preferably less than 300.
Suitable monofunctional compounds include n-hexanol~
n-octanol and amides such as ~ caprolactam~ The preferred
2s compounds containing 2 to 4 isocyanate-r~active groups include
ethylene glycol; propylene glycol; the isomeric butanediols,
pentanediols, hexanediols, octanediols, polyethylene glycols
and polypropylene glycols; glycerol; trimethylolpropane;
pentaerythritol; sorbltol; mannitol; the ethoxylation or
propoxylation products of these hlgher-functional alcohols; and
mixtures of these compounds.
Optional component a2) is present in an amount of up to 10
wt%, preferably up to 5 wt%, based on the weight of component
al). ~he nature and proportions of the individual components
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2~3~
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al) and a2) are chosen such that component a) has the required
OH number and hydroxyl functionality.
Polyisocyanate component b) is selected from
polyisocyanates having aliphatically, cycloaliphaticaliy,
araliphatically and/or aromatically bound isocyanate groups
which may optionally contain nonionic hydrophilic groups and/or
cationic groups. The polyisocyanate is preferably liquid at
room temperature. Solid polyisocyanates may also be used, but
it is recommended that they be used with small amounts of
lo solvents such as toluene, ethyl acetate, solvent naphtha,
propylene glycol ether acetate, propylene glycol diacetate,
d;propylene glycol diacetate~ N-methylpyrrolidone or ethylene
glycol dimethyl ether.
Polyisocyanate component b3 preferably has a viscosity of
50 to 10,000, more preferably 50 to 1000 mPa.s at 23C. It is
particularly preferred to use a polyisocyanate mixture having
exclusively aliphatically and/or cycloal;phatically bound
isocyanate groups, an average NCO functionality of 2.2 and 5.0
and a viscosity at 23aC of 50 to 5000 mPa.s.
Suitable polyisocyanates for use as component b) are
polyisocyanates derivatives having aromatically or
(cyclo)aliphatically bound isocyanate groups, preferably
(cyclo~aliphatically bound isocyanate groups.
Polyisocyanates derivatives prepared from hexa~ethylene
diisocyanate, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-
cyclohexane (IPDI~ and/or 4,4'-bis-(isocyanatocyclohexyl)-
methane are very suitable, especia71y those prepared
exclusively fro~ hexamethylene diisocyanate. Polyisocyanate
derivatives include polyisocyanates having biuret, urethane,
3~ uretdione and/or isocyanurate groups. These polyisocyanates
are generally prepared from diisocyanates and are preferably
subsequently treated to remove excess starting isocyanate in
known Inanner, preferably by distillation, to a residual content
of less than 0.5 wt%.
Mo3851
8 ~ ~
Preferred polyisocyanate derivatives include
poly;socyanates which conta;n biuret groups, are prepared from
hexamethylene diisocyanate in accordance with the processes
described, e.g., in U.S. Patents 3,l24,605, 3,358,010,
3,903,126, 3,903,127, or 3,976,627, and contain mixtures of
N,N',N"-tris-(6-;socyanatohexyl)biuret with minor amounts of
its higher homolog; and polyisocyanates which contain
isocyanura~e groups~ are prepared by the trimerization of
hexamethylene diisocyanate in accordance with the process
described, e.g., in U.S. Patent 4,324,879, and contain mixtures
of N,N',N"-tris-(6-isocyanato-hexyl)-isocyanurate with minor
amounts o~ its higher homolog. Especially preferred are
polyisocyanates which contain uretdione and isocyanurate groups
and are prepared by the catalytic oligomerization of
hexamethylene diisocyanate in the presence of trialkyl-
phosphines. Especia71y preferred are latter polyisocyanates
having a viscosity of 50 to 500 mPa.s at 23C and an NCO
functionality of 2.2 to 5Ø
The less preferred aromatic polyisocyanates include
polyisocyanate derivatives prepared from 2,4-diisocyanato-
toluene or mixtures thereof with 2,6-diisocyanatotoluene or
prepared fro~ 4,4'-diisocyanatodiphenylmethane or mixtures
thereof with its isomers and/or higher homoloyues. The
aromatic polyisocyanate derivatives in~lude those containing
urethane groups which may be prepared by the reaction of excess
amounts of 2,4-diisocyanatotoluene with polyhydric alcohols,
such as trimethylolpropane, followed by removal by distillation
of the unreacted excess diisocyanate. Other aromatic
polyisocyanate derivatives include the trimers prepared from
aromatic diisocyanates from which excess monomeric
diisocyanates have preferably been removed by distillation
follow~ng their production.
The use of hydrophilically modified polyisocyanates as
component b) or as a portion of component b) is particularly
preferred and is generally advantageous due to the additional
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emulsifying effect. Such hydrophilic mod1fication of the
polyisocyanates can be carried out by reac~ing a portion of the
isocyanate groups with monovalent polyether alcohols having
ethylene oxide units, for example, the ethoxylation products of
monomeric alkanols having 5 to 100 ethylene oxide units per
molecule. These polyether alcohols and their production are
described for example in DE-OS 3 521 618. Cationic
modification of the polyisocyanates can also be carried out for
example by reacting the polyisocyanates with a less than
stoichiometric amount of an aminoalcohol containing at least
one tertiary amino group, which is then subsequently converted
with a suitable acid, such as anhydrous methanesulphonic acid,
or by quaternization, into an ammonium group.
Especially suitable polyisocyanates b) ~ethosehaving~n
NCO content of 5 to 30 wt%~ an NCO functionality of 2.2 to 5.0,
and a content of incorporated ammonium groups, =N=+, of 10 to
250 m;lliequivalents per lOO g of polyisocyanate b). The use
of such cationically modified polyisocyanates is especially
advantageous because in this embodiment both the component a)
20 and the polyisocyanate component b) have incorporated cations.
This results in a synergism such that at a constant total
concer.tration of cations, better emulsifiability of the overall
system can be observed.
It is also possible to modify polyisocyanate component b)
25 so that itcont~ns both nonionic hydrophilic groups and cationic
groups. It is also possible to use hydrophobic polyisocyanates
without any hydrophilic modification. These polyisocyanates
are also emulsifiable in the system since component a) can
perform the function of an emulsifier for these polyiso-
cyanates.
The coating compositions according to the invention mayalso contain the known auxiliary agents and additives from
polyurethane coatings technology. Examples include pigments,
antifoaming agents, levelling agents, dispersant aids for
pigment distribution, thickeners, driers, extenders, catalysts
Mo3851
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for the isocyanate addition reaction, and less preferably
solvents that are not incorporated in the film.
To produce the coating composi~ions, the polyisocyanate
component b~ is emulsified into the aqueous solution or
dispersion of component al). Component a2) can be stirred into
the system before or after the addition of polyisocyanate
component b). The intermixing can be carried out simply by
stirring at room temperature. The amount of polyisocyanate
component b) is selected to provide an equivalent ratio of
isocyanate groups of component b) to isocyanate-reactive groups
of components a) of 0.5:1 to 5:1, preferably 0.8:1 to 3:1.
Components a) and b) are also preferably selected to provide an
average functionality for these components with regard to the
isocyanate addition reaction of at least 2.5 groups/mole.
If emulsifiable polyisocyanates are used, the coating
compositions may also be prepared by emulsifyiny the polyiso-
cyanates in water and then mix;ng them with the cationic
polyhydroxyl compound. The reactive diluent may optionally be
added in a final stage.
The ~ptional auxiliary agents and addi~ives are
incorporated into the system by stirring, preferably before the
addition of polyisocyanate component b).
The present invention makes available for the first time,
aqueous cationic two-component polyurethane coating
compositions which cure to high-quality crosslinked coatings.
This is due to the fact that the binder components a) and b)
are essentially branched substances which cure to h1ghly
crossiinked systems and are neither soluble nor dispersible in
water after the components have reacted. Accordlngly, the
cuating compos~tions according to the invention having only a
~nite pot life such that they yel after a certain time period.
The fundamental advantage of the systems according to the
inventlon over corresponding anionically modified systems is to
that the pot life ls considerably extended. In addition to the
ecological advantages of these new coating compositions and the
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improvements in processing viscosity and flow properties, there
is the additional ability to alter the coatings properties
through the choice of the reactive diluent. Thus, brittle
coatings can be adjusted to be more flexible by the appropriate
s choice of the reaotive diluent, it is known that long chain
diols have a flexibilizing effect.
In a binder sys$em with a relatively low crosslinking
density, harder and more resistant coatings can be produced
through the use of tri- or polyfunctional reactive diluents.
The coatings may be cured either at r~om temperature or at
elevated temperatures. The choice of the reactive diluents
depends upon both the reactivity of the polyisocyanates and/or
the catalysis, and on the curing condit;ons. More volatile
reactive diluents should preferably be used when the
composition is cured at room temperature or slightly
elevated temperature. At higher stoving temperatures and long
crosslinking times, the use of less volatile reactive diluents
is recommended.
The aqueous binder systems according to the invention are
suitable for coating any water-resistant substrates, especially
for the production of air- or heat-drying coatings on wood,
concrete, masonry or metallic substrates. They are also
suitable for the corrosion protection of metals, such as steel,
and as automotive coatings, especially as cationic primers.
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
PolYhYdroxvl Com~ounds
3~ PlY~_er 1
A poly(neopentyl glycol adipate) having a molecular weight
(Mn) of 1000
A poly(1,6-hexanediol/neopentyl glycol adipate) having a
molecular weight (Mn) of 1700. (Weight ratio of diols - 3:2).
Mo38S1
~3,~9~
- 15 -
PolYester 3
A polyethylene glycol adipate haYiny a molecular weight
(Mn) of 1750.
Polyether 1
A monohydric polyether alcohol having a molecular weight
of 2150 and prepared by the alkoxylation of n-bukanol using a
mixture of ethylene oxide and propylene oxide at a weight ratio
of EO:P0 = 4-1.
Polvether 2
A monofunctional ethylene ox;de polyether having a
molecular weight of 1210 and prepared by the ethoxylation of
3-ethyl-3-hydroxymethyloxetane.
Polvisocyanates
PolyisocYanate 1
15 g of Polyether 2 and 15 9 of hydroxyethylmorpholine
were added with stirring at 50C to 250 g of a 70% solution of
isophorone diisocyanate trimer in Solvesso 100 solvent. rhe
mixture was heated to 100C and ma;ntained at that temperature
for 2 hours. After coolin~ to 80C, the m;xture was catalyzed
with 3 drops of tin octanoate, held for 30 minutes at ~his
temperature and dissolved at a concentration of 60% in 61.6 g
of methoxypropyl acetate. Finally, at 50C~ the product was
alkylated with 10.15 g of dimethyl sulphate in 90 g of
methoxypropyl acetate. After 1 hour the product was cooled to
room temperature. A 50% solution of a water-dispersible
cationic polyisocyanate resin having an NC0 content of 10~2%
was obtained.
PolYisocYanate 2
37.5 g of Polyether 2 were added with stirring at 50C to
300 g of a 50% solution of isophorone diisocyanate trimer in
propylene glycol diacetate. The mixture was heated to 100C
and maintained at that temperature for 2 hours. After cooling
to 80C, the mixture was catalyzed with 1 drop of tin octanoate
dissolved in 3.4 g of propylene glycol diacetate. The mixture
was kepk for 2 hours at this temperature and then cooled to
Mo3851
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room temperature. A 55% solution of a water-dispersible
polyisocyanate resin was obtained having an NC0 content of
13.0% and a YiSCosity of 370 mPa.s/23C.
PolyisocYanate 3
The preparation of Polyisocyanate 2 was repeated except
that the amount of propylene glycol diacetate was reduced to
provide a 60% solution having an NC0 content of 13.0% and a
viscosity 780 mPa.s/23C.
PolyisocYanate 4
lo 132 9 of a polyethylene oxide alcohol having a molecular
weight of 350 and prepared by the ethoxylation of methyl glycol
were added with stirring to 750 9 of a hexamethylene
diisocyanate trimer having an NC0 content of ~1.5%. The
mixture was heated to 11~C and maintained for 2.5 hours at
that temperature. After cooling, a colorless resin having an
NC0 content of 16.7% was obtained.
PolYisocvanate 5
A hydrophilically modified polyisocyanate having an NC0
content of 18.4% and was prepared accord;ng to Example 1 of
U.S, Patent 4,663,377 by reactiny a hexamethylene diisocyanate
trimer having an NC0 content of of 21.6% with an ethoxylated
n-butanol having a molecular weight 1145.
PreE3~cation of aq~ us dispersions ali
of_cationically modified polYhYdroxYl comPounds
Example 1
123.8 9 (0.472 moles) of 4,4'-diisocyanatodicyclohexyl-
methane (technical mixture of isomers) were added ak 50C to
157.5 g ~0.157 moles) of polyester 1 and 18.74 g (0.157 moles)
of N-methyldiethanolamine. The mixture was heated to 100C and
that temperature was maintained for 2 hours. The mixture was
then dissolved in 253 ml of ~ acetone and the NC0 content was
determined. At 30C, 29.6 9 (0.281 moles) of diethanolalnine
were added and the mixture was then stirred for 10 minutes and
neutralized with 11.34 9 of (00126 moles) of DL-lactic acid.
After 5 minutes the product was dispersed with 775 ml of water
Mo3851
2~3~8~
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and the solvent was then distilled off under vacuum. A fine
particle size dispersion was obtained which had a solids
content of 30% and a pH of 5. The solids had an OH number of
B7 and contained 41 meq. (milliequivalents) of ammonium
nitrogen per 100 9.
ExamPle 2
115.1 9 (0.439 moles) of 4~4'-diisocyalnatodicyclohexyl-
methane ~technical mixture of isomers) were added at 50C7 to
165.2 g (0.165 moles~ of polyester 1 and 19.7 g (0.165 moles)
of N-methyldiethanolamine. The mixture was heated to 100C
and that temperature was rnainta;ned for 2 hours. The mixture
was then dissolved in 253 ml of acetone and the NCO con~ent
was determined. At 30~C, 17.9 9 (0.170 moles) of
diethanolamine and 1.6 g (0.001 moles) of isophoronediamine
were added and the mixture was then stirred for 10 minutes and
neutralized with 12 g (0,104 moles) of 85% phosphoric acid. After
5 minutes the product was dispersed with 780 ml of water and
the solvent was then distilled off under vacuum. A fine
particle size dispersion was obtained which had a solids
content of 31.7% and a pH of 4.7. The solids had an OH number
of 57 and contained 44.8 meq, of ammonium nitrogen per 100 9.
ExamPle 3
115.1 9 (0.439 moles) of 4,4'-diisocyanatodicyclohexyl-
methane (technical mixture of isomers) were added at 50QC to
2 165.2 g (0.165 moles) of polyester 1 and 19.7 9 (0.165 moles)
of N-methyldiethanolamine. The mixture was heated to lOO~C and
that temperature was maintained for 2 hours. The product was
then dissolved in 253 ml of acetone and the NCO content was
determined. At 30C, 19.2 g (0.183 moles) of diethanolamine
were added and the mixture was then stirred for 10 minutes and
neutralized with 13.4 9 (0.149 moles) of DL-lactic acid
dissolved in 20 ml of water. After 5 minutes the product was
dispersed with 760 ml of water and the solvent was then
distilled off under vacuum. A fine particle size dispersion
was obtained which had a solids content of 32.4% and a pH of
Mo3851
- 18 ^
4.7. The solids had an OH number of 63 and contained 44.7 meq.
of ammonium nitrogen per 100 9.
Example 4
81.5 g ~0.311 moles) of 4,4'-diisocyanatodicyclohexyl-
methane (technical mixture of isomers) were added at 50C to
~04.6 g (0.117 moles) of ?olyester 3 and 13.9 9 (0.117 moles)
of N-methyldiethanolamine. The mixture was heated to 100C
and that temperature was maintained for 3 hours. The product
was then dissolved in 253 ml of aceto"e and the NCO content
o was determined. At 30C, 12.4 9 (0.118 moles) of
diethanolamine were added and the mixture was then stirred for
10 minutes and neutralized with 9.5 g (0.105 moles) of
DL-lactic acid dissolved in 20 ml of water. After 5 minutes,
the product was dispersed with 750 ml of water and the solvent
was then distilled off under vacuum. A fine particle size
dispersion which had a solids content of 33.1% and a pH of 5.6.
The solids had an OH number of 41 and contained 32 meq. of
ammonium nitrogen per 100 g.
Example 5
318.5 g o~ n-butyl acetate were charged and a nitrogen
purge was applied to a 3-liter stirred flask having a flat
blade paddle agitator, reflux condenser and thermometer as well
as a gas inlet and outlet. The flask was then heated to an
internal temperature of 110C. Subsequently, over the course
of 6 hours, a monomer mixture of 344 g of 2-hydroxyethyl
methacrylate, 600 g of n-butyl acrylate, 346 g of methyl
methacrylate and lSO g of 2-(N-dimethylamino)ethyl methacrylate
as well as an initiator solution of 50 g of isobutyronitrile in
763 g of n-butyl acetate were charged at a constant rate to the
flask. The flask was then cooled to an internal temperature of
100C and the mixture reactivated w;th an init;ator solution of
10 g of t-butyl per-2-ethylhexanoate in 94 g of n-butyl
acetate. Stirring was continued for a further 4 hours. The
polymer solution was subsequently combined with a solution of
34 g of acetic acid in 3300 g of deionized water. Afterwards,
Mo3851
2 ~
butyl acetate together with water was distilled off
azeotropically, and the residue adjusted with fresh deionized
water to a concentration of 37.0 wt%. The pH value of this
dispersion was 5.~, the viscosity was 13,900 mPa.s
(structurally viscous behavior) and the aver~ge particle
diameter measured by laser correlation spectroscopy was 195 nm.
Films cast on glass plates, after drying at room temperature,
were clear and elastic.
Coatinq Exam~
Comparative ExamDle 1
A 30% dispersion of an ionically modified hydroxyl group-
contain;ng polyacrylate res;n (hydroxyl group content of the
dispersion: 1.2%) was mixed with a hydrophobic, isocyanurate-
group-containing polyisocyanate prepared from hexamethylene
diisocyanate and haviny an NCO content of 19.8% using a
disperser ~NCO/OH equivalent ratio = 0.25:1) and the resulting
mixture was applied to a glass support. The pot life of the
coating mixture as well as the mechanical and physical
properties of the resulting coating are set forth in Table 1.
ComParative ExamPles 2 to 4
ComparatiYe Example 1 was repeated with the exception that
the NCO/OH e~uivalent ratios for Comparison Examples 2, 3, and
4 were 0.5:1, 0.75:1 and 1:1, respectively. The pot lives of
the coating mixtures as well as the mechanical and phys;cal
properties of the resulting coatings are set forth in Table 1.
Comparative Examples 5 and 6
Comparative Example 1 was repeated with the except;on that
the NCO/OH equivalent ratios for Comparison Examples 5 and 6
were 2:1 and 3:1, respectively. The pot lives of the coating
mixtures as well as the mechanical and physical properties of
the resulting coatings are set forth in Table 1.
Coa~g Examples 1 to 4
The OH group-containing cationic polyurethane of Example 3
was mixed with each of Polyisocyanates 1~ 2~ 4 and 5 at an
NCO/OH equivalent ratio of 0.25:1 using a disperser, and the
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2~8~5
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resulting mixtures were applied to glass supports to prepare
coat~ngs. The pot lives of the coating mixtures and the
mechanical and physical properties of the resulting coatings
are set forth in Table 2.
Coatinq Examples 5 to 7
The cationic water-dilutable resins of Examples 3, 2 and 1
were mixed with Polyisocyanate 3 ~30% in water) at an NCO/OH
equivalent ratio of O.S:l using a disperser and the resulting
mixtures were applied to glass supports to prepare coatings.
The pot lives oF the coating mixture and the mechanical and
physical properties of the resulting coatings are set forth in
Table 3.
Coatinq ExamDles 8 to 10
Coating Examples 5 to 7 were repeated with the exception
that the NCO/OH equivalent ratio was 0.75:1. The pot lives of
the coating mixtures and the mechanical and physical properties
of the resulting coatings are set forth in Table 3.
Coatinq Examples 11 to 13
Coating Examples 5 to 7 were repeated with the exception
that the NCO/OH equivalent ratio was O 1. The pot lives of
the coating mixtures and the mechanical and physical properties
of the resulting coatings are set forth in Table 3.
Coatinq Examples 14 and 15
The OH group-containing cationic polyurethanes of Examples
2 and 3 were each mixed with Polyisocyanate 3 ~30% in water) at
an NCO/OH equivalent ratio of 2:1 using a disperser and the
resulting mixtures were applied to glass supports to prepare
coatings. The pot lives of the coating mixtures and the
mechanical and physical properties of the resulting coatings
are set forth in Table 3.
Coatin~LExamPles 16 and 17
Coating Examples 14 and 15 were repeated with the
exception that the NCO/OH equivalent ratlo was 3:1. The pot
lives of the coating mlxtures and the mechanical and physical
properties of the resulting coatings are set Forth ln Table 3.
Mo3851
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Çoatinq ExamPles 18 and 19
Coating Examples 14 and 15 were repeated with the
exception that the NCO/OH equivalent ratio was 4:1. The pot
lives of the coating mixtures and the mechanical and physical
properties of the resulting coatings are set forth in Table 3.
Coatinq ExamPles 20_and 21
The OH group-containing cationic polyurethanes of Examples
2 and 3 were each mixed with Polyisocyanate 4 530% in water) at
an NCO/OH equ;valent ratio of 0.75:1 usint~ a disperser and the
result;ng mixtures were applied to glass supports to prepare
coatings. The pot lives of the coating mixtures and the
mechanical and physical properties of the resulting coatings
are set forth in Table 4.
Coatinq Examples 22 and 23
Coating Examples 20 and 21 ~ere repeated with the
exception that the NCO/OH equivalent ratio was 1:1. The pot
lives of the coating mixtures and the mechanical and physical
properties of the resulting coatings are set forth in Table 4.
Coati~ Examples 24_and 25
Coa~ing Examples 20 and 21 were repeated with the
except;on that the NCO~OH equivalent ratio was 2:1. The pot
lives of the coating mixtures and the mechanical and physical
properties of the result;ng coat;ngs are set forth in Table 4.
Ooat;nq Examples 26 and 27
Coating Examples 20 and 21 were repeated with thP
exception that the NCO/OH equ;valent rat;o was 3:1. The pot
lives of the coat;ng mixtures and the mechanical and physical
properties of the resulting coatings are set forth in Table 4.
Coat;ngLE_amples 28 and 29
Coating Examples 20 and 21 were repeated with the
exception that the NCO/OH equivalent ratio was 4:1. The pot
lives of the coating mixtures and the mechanical and physical
properties of the resulting coatings are set forth in Table 4.
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Coat;nq ExamDle 30
410.1 g of the cationically ~odified polyhydroxyl compound
of Example 3, 2.8 9 of a commercial emulsifier (~5% aqueous
solution of "Emulsifier WN"7 manufacturer: Bayer QG,
Leverkusenj and 12 9 of a 5% aqueous solution oF a commercial
thickener ~Borchigel DP 40, manufacturer: Gebr. Borchers AG)
were mixed to prepare a p;gmented coating composition. 85 g of
a commercial ;ron oxide pigment (Bayferrox 130 BM,
~anufacturer: Bayer AG) were dispersed in the mixture. 86.8 9
o of Polyisocyanate 2 were added to this forlnulation (NCO/OH
equivalent ratio 1:1). The coating compdsition was
homogenized with a dissolver and applied to two glass supports.
One coating was cured at room temperature, while thP other was
cured at 120~C.
Room temDerature curinq 120 C curinq/45 minutes
Sand dry = 4 hours
~hrough dry ~ 16 hours Pendulum hardness = 100 sec
Standing time > 2 days Gloss 6V = 90
Pendulum hardness = 2C seconds
Gloss 60 = 91
Coating Example 31
A formulation was prepared as in Example 30. To this
formulation was added 183.6 9 of Polyisocyanate 2, 1.34 9 of
trimethylolpropane as reactive diluent and 51 g of water
(NCO~OH equivalent ratio 1:1). A coated was prepared as
described in Example 30 and cured at room temperature.
Sand dry = 5.5 hours
Through dry - 16 hours
Standing time >2 days
Pendulum hardness = 20 seconds
Gloss 60~ ~ 89
Co~tinq ExamPle 32
lOO g of the OH group-containing cationic resin of Example
5 were homogeneously mixed with 41 g of Polyisocyanate 2
(NCO/OH equivalent ratlo - 1`1) using a dissolver. The mixture
was applied to a glass support and the coating properties were
determined after curing for one week at room temperature.
Mo3851
2~3~
- 26 -
Sand dry lQO min
Pendulum hardness (7 d) 161 sec
Water resistance ~7 d~ O
White Spirit resistanee (7 dJ O
s Acetone resistanc~ (7 d) 3
The mixture had a working time oF more than 16 h and was
being applied without difficulty after 24 h.
Coatinq_ xamDle 33
100 g of the OH group-containing cationic resin of Example
o 5 were homogeneously mixed with 82 g of Polyisocyanate 2
(NCO/OH equivalent ratio - 2:1~ using a dissolver. The mixture
was applied to a glass support and the coating properties were
determined after curing for one week at room temperature.
- Sand dry 100 min
Pendulum hardness (7 d) 179 sec
Water resistance (7 d)
White Splrit resistance (7 d) O
Acetone resistance (7 d) 3
The mixture had a working tim~ of more than 16 h and was
applied without difficulty after 24 h.
Coating ExamPle 34
100 9 of the OH group-containing cationic resin of Example
5 were homogeneously mixed with 123 g of Polyisocyanate 2
(NCO/OH equivalent ratio - 3:1) using a dissolver. The mixture
was applied to a glass support and the coating properties were
determined after curing for one week at room temperature.
Sand dry 140 min
Pendulum hardness (7 d) 176 sec
Water resistance (7 d) O
Whlte Spirit resistance (7 d) O
Acetone resistance (7 d) 3
The mixture had a working time of more than 16 h and was
applied without difficulty a~ter 24 h.
.
3s
Mo3851
2~$~
- 27 -
Although the inven~ion has been described in detail in the
foregoing for the purpose of illustra~ion, it is to be
understood that such detail is solely for that purpose and that
variations can be made ~herein 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.
Mo3851
