Note: Descriptions are shown in the official language in which they were submitted.
2 1 3 ~
; 1
WATER-DISPERSIBLE POLYURETHANES
Backqround of the Invention
The present invention relates to aqueous polyurethane
dispersions which do not require emulsifier and can be
used, for example, to produce coatings on fabrics, wood,
paper, or metal surfaces.
Particularly favorable mechanical properties of
polyurethane coatings such as hardness and resistance to
abrasion, scratching, and impact, can be achieved using
high molecular weight polyurethanes. High molecular
weight polyurethanes, however, are difficult to handle in
the melt because of their high viscosities, and it is
therefore preferred to work in solvents. On the other
hand, environmental considerations dictate that solvents
are to bé eliminated if possible or minimized.
Dispersibility in water necessitates the presence of a
sufficient number of hydrophilic groups in the polymer.
Aqueous polyurethane dispersions are described in
DE-C 14 ~5 74~. In this case, dispersibility in water is
achieved by adding on to the isocyanate-terminated
prepolymers compounds which, in addition to containing an
active hydrogen atom which reacts with the isocyanate
group, also carry a salt-liXe group or a group capable of
forming a salt, for example, a quaternized amino group.
Another embodiment which is described, is the reaction of
the prepolymer with a compound which has an isocyanate
group in addition to the group which is salt-like or
capable of forming salts.
DE-C 14 95 847 describes a process for the
preparation of anionic polyurethanes, in which
polyisocyanates are reacted, in the presence of acetone
as solvent, with essentially linear compounds having
reactive hydrogen atoms and a molecular mass of from 300
to 10,000 g/mol. The compound reacted carries a carboxyl
or sulfo group and at least one hydrogen atom which is
reactive toward isocyanate.
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DE-C 19 54 090 describes the preparation of salts of
2-(~-aminopropionamido)alkanesulfonic acid and their use
as anionic component in the preparation of polyurethane
dispersions.
DE-A 20 35 732 describes a process for the
preparation of ~ salts of N-(~-aminoalkane)-~-
aminoalkanesulfonic acid and their use as anionic
component in the preparation of polyurethane dispersions
which are free of emulsifier.
In the documents mentioned above, the starting
component is a polyurethane prepolymer which at this
stage still carries no ionic or ionogenic groups. The
introduction of ionogenic structures enables
dispersibility in water, but as described, the reactive
isocyanate groups of the prepolymer are always fully used
up by reaction. The introduction of these groups
therefore puts a stop to addition polymerization. It is
then no longer readily possible to raise the molecular
mass subsequently in order to improve the mechanical
properties. Although the text of these documents does
indeed mêntion~the preparation from urethane prepolymers
in a solvent-free melt, in the examples, the reactions
are always carried out in a solvent, in order to prevent
the viscosity from rising excessively.
Summary of the Invention
:.. - ~ ,.
It is therefore an object of the present invention
to p~ovide polyurethanes `and processes for their
preparation and use, which polyurethanes can be dispersed
in water without emulsifier, contain no solvent and,
despite a high molecular mass, can be processed without
problems.
In accordance with the objects, there has been
provided a polyurethane which is dispersible in water
without emulsifier, obtained by reaction of a portion of
the isocyanate groups of an isocyanate-terminated
urethane prepolymer with a salt of an acid having a
hydrogen atom which is reactive toward isocyanate,
.7
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followed by reaction of remaining isocyanate groups with
a chain-extending agent.
In accordance with the objects, there has also been
provided a process of preparing a polyurethane which is
dispersible in water without emulsifier comprising,
reaction of a portion of the isocyanate groups of an
isocyanate-terminated urethane prepolymer with a salt of
an acid having a hydrogen atom which is reactive towards
the isocyanate groups, followed by reaction of remaining
isocyanate group with a chain-extending agent.
There has also been provided methods of using the
polyurethane in adhesive and coating compositions and
articles coated with the polyurethane.
Further objects, features, and advantages of the ~-
invention will become apparent from the detailed
description which follows. -
... , - ---- :
Detailed Description
~ ~.,.'..:
The invention relates to polyurethanes which can be
dispersed~in water without emulsifier and are obtained by
partial reaction of an isocyanate-terminated urethane
prepolymer with a salt of an acid having a hydrogen atom
which is reactive toward isocyanate, followed by reaction
of the remaining isocyanate groups with a chain-extending
agent.
In this context the quantity of salt should be chosen
such that only a fraction, generally from 20 to 80%,
preferably from 30 to 60%, of the terminal isocyanate
group is reacted. This makes it possible, by adding a
suitable chain-extending agent, such as a polyamine, and
an appropriate quantity of water, in a subsequent step,
to carry out a chain extension. In this context the
quantity of water should be calculated such that the rise
in viscosity caused by the chain extension is compensated
by this dilution.
Linear or branched polyurethanes are obtained which
carry acid groups at the chain ends and have urea groups
within the chain and/or at the branching sites. This
~.,~,, ~
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molecular structure leads to fine polyurethane
dispersions which are stable on storage, are stable to
hydrolysis, and give films displaying a high degree of
resistance to swelling by water.
The isocyanate-terminated urethane prepolymers are
prepared in any desired manner, such as by reacting one
or more high molecular weight polyols A, if desired with
the addition of low molecular weight polyols, polyamines
or polythiols A', with one or more polyisocyanates B in
the melt at, for example, from 60 to 130C.
Subsequently added to this polyisocyanate melt is a
salt C of an acid having a hydrogen atom which is
reactive toward isocyanate. Any salt of any acid may be
used. Examples of appropriate acids include carboxylic,
sulfonic or phosphonic acids, the molecule of which
contains a hydroxyl or acidic amino group. The salt can
be added in any desired manner to the prepolymer, for
example, as a solid or in the form of an aqueous solution
at a temperature below 100C. It is also possible to use
mixtures of several such salts.
After~ this~reaction, one or more chain extenders is
reacted with the remaining isocyanate groups. This is
accomplished, for example, by either preparing a
dispersion of the prepolymer by the addition of water,
and then chain extension is accomplished by adding a
chain-extender, such as a polyamine D (process I); or
chain extension is first carried out by adding chain~
extender D in a small quantity of water to the
prepolymer, followed by dispersion in a larger quantity
of water (process II). It is also possible, in
accordance with the invention, to dissolve the chain-
extender D required for chain extension in the total
quantity of dispersion water and therefore to add it to
the isocyanate-containing urethane prepolymer at the same
time as the water (process III). Likewise, chain
extension can also be achieved by a partial hydrolysis of
the isocyanate groups followed by reaction of the
resulting amines with the remaining isocyanate groups
(process IV). In all of the processes described, the
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temperature of the dispersion water may vary, and be
between 0 and 100C, with a range from 20 to 80C being
preferred.
The high molecular weight polyols A which are
suitable for the invention are any of those
conventionally used in the preparation of polyurethanes.
They are chosen, for example, from any of the types of
polyetherpolyols, polyesterpolyols, polylactonepolyols,
and polycarbonatepolyols. Example of preferred polyols
are as follows.
Suitable polyetherpolyols include compounds of the
formula
H - [ - O - (CHR) n~]m OH
in which '-
15 R is hydrogen or a lower (C1 - C6) alkyl radical which
may hav'e^'various substituents,
n is a number from 2 to 6, and --
m is a number from 10 to 120. -~ '
Examples are poly(oxytetramethylene) glycols,
poly(oxye'thyle~e) glycols and poly(oxypropylene) glycols. '
The preferred polyetherpolyols are poly(oxypropylene)
glycols having a molecular mass in the range from 400 to '~
5000 g/mol. ~; ~
The polyesterpolyols are generally prepared by -'`-''~~'
esterifying any desired organic polycarboxylic acids or
their anhydrides with desired organic polyols. The - --~
polycarboxylic acids and the polyols may be aliphatic or
aromatic polycarboxylic acids and polyols. ''~
The polyols used for the preparation include alkylene ;~
glycols such as ethylene glycol, butylene glycol,
neopentylglycol, hexane-1,6-diol and other glycols, such ~' '
as dimethylolcyclohexane, and trishydroxyalkylalkanes,
such as trimethylolpropane, and tetrakishydroxyalkyl- ;
i alkanes, for example, pentaerythritol.
The acid component of the polyester polyols generally
primarily comprises low molecular weight polycarboxylic -
acids or their anhydrides having 2 to 18 carbon atoms in
the molecule. Examples of suitable acids include
- 2~3~3`3~
.~
;- 6
phthalic acid, isophthalic acid, terephthalic acid,
tetrahydrophthalic acid, hexahydrophthalic acid, succinic
acid, adipic acid, azelaic acid, sebacic acid, maleic
acid, glutaric acid, hexachloroheptanedi-carboxylic acid,
alkyl- and alkenylsuccinic acids, for example, n-
octenylsuccinic acid, n- and iso-dodecenylsuccinic acid,
tetrachlorophthalic acid, trimellitic acid and
pyromellitic acid. Instead of these acids it is also
possible to use their anhydrides where these exist. ~ .
Dimeric and trimeric fatty acids can also be employed as
polycarboxylic acids. Terephthalic acid, adipic acid and ~-`
maleic acid are particularly preferred.
The terms polyetherpolyols and polyesterpolyols also
include products of this kind containing monomers with - -
carboxylic acid, phosphonic acid or sulfonic acid groups.
Furthermore, it is also possible in the invention to
use polyesterpoiyols which are derived from lactones.
These products are obtained by, for example, reacting an
~-caprolactone with a polyol. Products of this kind are ~ ;-`
described in US-A 3 169 945, which is incorporated by ;~
reference~in i~ts entirety. ~- -
The polylactonepolyols obtained by this reaction are
distinguished by the presence of a terminal hydroxyl
group and by recurring polyester units which are derived
from the lactone. These recurring molecular units may be ~ -
of the formula
O ........................................... ~ :`
'' 1 1 ` ~,
- C - ( CHR~ n - CH 2 - :~
' '`: : .-
in which n is an integer, preferably 4 to 6, and the -
substituent R is hydrogen, an alkyl radical, a cycloalkyl
radical or an alkoxy radical, with no substituent
containing more than 12 carbon atoms.
The lactone used as starting material may be any
desired lactone or any desired combination of lactones; -:
this lactone should contain at least 6 carbon atoms in
~:~3~ 3~
the ring, for example, 6 to 8 carbon atoms, and at least
2 substituents of hydrogen should be present on the
carbon atom attached to the oxygen group of the ring.
The lactone used as starting material may be represented
by the following formula:
CH2C CR 2 ~n C O
O
in which n and R are as defined above.
The lactones preferred in the invention are the ~-
caprolactones in which n has the value 4. The most
preferred lactone is unsubstituted ~-caprolactone, in
which n has the value 4 and all the substituents R are
hydrogen. This lactone is particularly preferred since
it is available in large quantities and gives coatings
having excellent properties. In addition, it is also
possible to use various other lactones, singly or in
combination.
Any aesired polyol can be used to react with the
lactone. Examples of aliphatic polyols which are
suitable for reaction with the lactone include ethylene
glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol,
dimethylolcyclohexane, trimethylolpropane and
pentaerythritol.
Other suitable starting compounds A are
polycarbonate-polyols or polycarbonatediols, for example,
of the formula
O
H O ~ O - C - O - R - ) n ~ O H
in which R is an alkylene radical. These OH-functional
polycarbonates can be prepared by reacting polyols, such
as propane-1,3-diol, butane-1,4-diol, hexane-1,6-diol,
diethylene glycol, triethylene glycol, 1,4-bishydroxy-
~ K j
1 ~ r~ -
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: 8
methylcyclohexane, 2,2-bis(4-hydroxycyclohexyl)propane,
neopentylglycol,trimethylolpropane,andpentaerythritol,
with dicarbonates such as dimethyl, diethyl or diphenyl
carbonate, or with phosgene. Mixtures of such polyols
also can be employed.
The polyetherpolyols, polyesterpolyols, polylactone-
polyols and polycarbonatepolyols described above can be
employed alone or together. Furthermore, these polyols
A may also be employed together with different quantities
of low molecular weight, isocyanate-reactive polyols,
polyamines or polythiols A'. Examples of compounds of
this kind are ethylene glycol, 1,2-propylene glycol or
1,3-propylene glycol, 1,4-butanediol or 1,3-butanediol,
1,6-hexanediol, the lower oligomers of the abovementioned
diols, pentaerythritol, trimethylolpropane,
ethylenediamine, propylenediamine, hexamethylenediamine
and 1,2-dimercaptoethane. Compounds having mixed
functional groups, for example, ethanolamine or 2-
mercaptoethanol, are also suitable. Ethylene glycol,
butanediol and hexanediol are particularly preferred.
Suitable polyisocyanates B are any in the art and
include all (cyclo)aliphatic, aromatic or mixed aromatic-
aliphatic diisocyanates as are conventionally employed in
polyurethane chemistry.
Examples of suitable polyisocyanates include tri-
methylene diisocyanates, tetramethylene diisocyanates,
pentamethylene diisocyanates, hexamethylene diiso-
cyanates, propylene diisocyanates, ethylethylene diiso-
cyana~es, 2,3-dimethylethylene diisocyanates, 1-methyl-
trimethylene diisocyanates, 1,3-cyclopentylene diiso-
cyanates, 1,4-cyclohexylene diisocyanates, 1,2-cyclo-
hexylene diisocyanates, 1,3-phenylene diisocyanates, 1,4-
phenylene diisocyanates, 2,4-tolylene diisocyanates
(TDI), 2,6-tolylene diisocyanates (TDI), 4,4'-biphenylene
diisocyanates, 1,5-naphthylene diisocyanates, 1,4-
naphthylene diisocyanates, l-isocyanatomethyl-5-iso-
cyanato-1,3,3-trimethylcyclohexane (IPDI), bis(4-iso-
cyanatocyclohexyl)methane, 4,4'-diisocyanatodiphenyl
ether, 2,3-bis-(8-isocyanatooctyl) -4-octyl-5-hexylcyclo-
2~3~
. `~. .-.
... g
hexene, trimethylhexamethylene diisocyanates,
tetramethylxylylene diisocyanates (TMXDI), isocyanurates
of the above diisocyanates, and allophanates of the above
diisocyanates. Mixtures of such di- or polyisocyanates
can also be employed. TDI, TMXDI and IPDI are
particularly preferred.
Suitable salts C of acids, preferably carboxylic,
sulfonic, or phosphonic acids which carry a hydroxyl or
amino group are derived from, for example,
hydroxycarboxylic acids, such as glycolic acid, lactic
acid, trichlorolactic acid, salicylic acid, 4-hydroxyiso~
phthalic acid, hydroxyterephthalic acid, 5,6,7,8-tetra-
hydro-2-naphthol-3-carboxylic acid, 1-hydroxy-2-naphthoic
acid, ~-hydroxypropionic acid and m-hydroxybenzoic acid;
aminocarboxylic acids such as anilidoacetic acid,
2-hydroxycarbazole-3-carboxylicacid,glycine, sarcosine,
methionine, ~-alanine, ~-alanine, 6-aminocaproic acid,
6-benzoylamino-2-chlorocaproicacid,4-aminobutyricacid,
aspartic acid, glutamic acid, histidine, anthranilic
acid, 2-ethylaminobenzoic acid, N-(2-carboxylphenyl)-
aminoacetic acid, 2-(3'-aminobenzenesulfonylamino)benzoic
acid, 3-aminobenzoic acid, 4-aminobenzoic acid, N-phenyl-
aminoacetic acid, 5-aminobenzenedicarboxylic acid and
5-(4'-aminobenzoyl-amino)-2-aminobenzoic acid;
hydroxysulfonicacidssuchas2-hydroxyethanesulfonic
acid, 2-phenolsulfonic acid, 3-phenolsulfonic acid,
4-phenylsulfonic acid, 2,4-phenoldisulfonic acid, 1-naph-
tholsulfonic acid, l-naphtholdisulfonic acid, 8-chloro-
1-naphtholdisulfonic acid, l-naphtholtrisulfonic acid,
2-naphthol-1-sulfonic acid, 2-naphtholtrisulfonic acid,
2-hydroxy-6-sulfo-3-naphthoic acid and 2-hydroxy-
carbazole-7-sulfonic acid;
aminosulfonic acids such as amidosulfonic acid,
hydroxylaminemonosulfonicacid,hydrazinedisulfonicacid,
sulfanilic acid, N-phenylaminomethanesulfonic acid,
4,6-dichloroaniline-2-sulfonic acid, 1,3-phenylene-
diamine-4,6-disulfonic acid, N-acetyl-1-naphthylamine-
3-sulfonic acid, 1-naphthylaminesulfonic acid,
2-naphthylaminesulfonic acid, naphthylaminedi-sulfonic
. ~ 2 ~ 3 ," .9 .~ ~
~,.~,.~ .. .
;,.` ";.,. 1o
acid, naphthylaminetrisulfonic acid, phenylhydrazine-
2,5-disulfonic acid, 2,3-dimethyl-4-aminoazobenzene-4,5'-
disulfonic acid, 4'-amino-4-(4-methoxyphenylazo)-
2,2'-disulfonic acid, carbazole-2,7-disulfonic acid,
taurine, methyltaurine, butyltaurine, 3-amino-5-sulfo-1-
benzoic acid, 3-methylanilino-methanesulfonic acid, 6-
nitro-1,3-dimethylbenzene-4-sulfamic acid, 2-aminophenol-
4-sulfonic acid, 2-methoxyanilinomethanesulfonic acid,
and 2-aminodiphenylaminesulfonic acid.
The salts of taurine and its derivatives are
particularly preferred.
The cations in these salts can be selected from the
alkali and alkaline earth metals, such as sodium
potassium, rubidium, magnesium, and calcium, and from
ammonium and its alkyl and aryl derivatives. Especially
preferred are alkali and ammonium salts.
- To extend the chain of the urethane prepolymers, one
or more chain extenders D are used. Chain extenders for
isocyanate-terminated polyurethane prepolymers are
selected from compounds that carry at least two groups
that are react~ve towards isocyanate groups. If used in
aqueous medium, like in this case, the reactivity of
these groups in the chain extender has to be greater than
that of water. Suitable highly reactive groups are
primary and secondary amino groups, and thiol (mercaptan)
groups. Chain extenders which can be used in the present
invention therefore comprise polyamines, polymercaptans,
and polyamino-polymercaptans with at least two isocyanate
reactive groups per molecule; Preferably a polyamine is
added which rea!cts with the remaining isocyanate groups.
Suitable polyamines are any known in the art, and include
ethylenediamine (EDA), hexamethylenediamine (HMDA),
1,4-cyclohexylenediamine, diaminodiphenylmethane,
diethylenetriamine (DETA), triethylenetetramine, tetra-
ethylenepentamine, triaminobenzene, 2-methyl-1,5-diamino-
pentane (Dytek A), the isomeric phenylenediamines, and
hydrazine. Suitable polymercaptans are dimercapto
toluene, and the ~,~-dimercapto alkanes like dimercapto
ethane, dimercapto propane, dimercaptobutane and
. ~ -
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.~`~
,.`,~j~ 11
dimercaptohexane, and 2,3-dimercapto propanol (BAL).
Suitable Mercaptoamines include cysteamine and mercapto
aniline. EDA, DETA, HMDA and Dytek A are particularly
preferred.
The advantage of the product and process according ~-
to the invention compared with the prior art are in the
separation of the steps -
a) introduction of ionic groups into the urethane
prepolymer, and
, ;,,
b) chain extension,
by using salts, preferably monofunctional salts (i.e.,
salts having one hydrogen atom which is reactive toward ~-
isocyanate groups), partial reaction of the isocyanate-
terminated prepolymer with the salt, and subsequent chain
extension. It is possible in accordance with the -
invention to carry out the reaction of the urethane
, , , - - -:
prepolymer with the salt either in bulk or in a small
quantity of water, and to carry out the subsequent chain
extension likewise in water. In this way, it is
generally possible to avoid the use of solvents.
In the prilor art, solvents are always employed in the
preparation of the polyurethane and/or in the subsequent
reaction with hydroxy- or amino-functional salts.
Although the oldest of the abovementioned documents,
DE-C 14 95 745, talks of a reaction in the melt, all of
the examples employ acetone as solvent. In the case of
the preparation or reaction of polyurethanes of
sufficiently high molecular weight, their high molecular
mass will mean that the viscosity of the mixtures will be
above the level which can be coped with in the melt. In
accordance with the invention, on the other hand, poly-
urethanes of high molecular mass are only formed when a
sufficient quantity of water is present to dilute the
solution and thus to reduce its viscosity.
The polyurethane dispersions which are obtainable
from these components by processes I to IV described
above are suitable for many applications, for example,
for the production of coating compositions for wood,
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12
textiles and metals, as binders for water-dilutable
adhesives or as resins for printing inks.
They are capable of being combined and are generally
compatible with other aqueous solutions and dispersions
of polymers, for example, acrylic and/or methacrylic
polymers, polyurethane, polyurea resins, polyester resins
and epoxy resins, thermoplastics based on polyvinyl
acetate, polyvinyl chloride, polyvinyl ether, polychloro-
prene and polyacrylonitrile, and ethylene-butadiene-
styrene copolymers. They also can be combined withthickening substances based on carboxyl-containing
polyacrylates or polyurethanes, hydroxyethylcellulose,
polyvinyl alcohols and inorganic thixotropic agents, such
as bentonite, sodium-magnesium and sodium-magnesium-
fluorine-lithium silicates.
The polyurethane dispersions according to the
invention can be applied to a wide variety of substrates,
examples being ceramic, wood, glass, concrete, preferably
plastics such as polycarbonate, polystyrene, polyvinyl
chloride, polyester, poly(meth)acrylates, acrylonitrile-
butadiene-styrene polymers and the like, and preferably
metals such as iron, copper, aluminum, steel, brass,
bronze, tin, zinc, titanium, magnesium and the like.
They adhere to the various substrates without adhesion-
promoting primers or intermediate layers.
The polyurethane dispersions according to theinvention are suitable, for example, for the production
of anticorrosion coatings and/or intermediate coatings
for a wide variety of applications, in particular for the
production of metallic and solid-color basecoats in
multicoat paint systems for the sectors of automotive
finishing and the coating of plastics, and for producing
primers for the sector of plastics coating.
- Because of the short flash-off times of the basecoats
based on the polyurethane dispersions according to the
invention, the pigmented basecoat can be coated over with
a clearcoat without a baking step (wet-on-wet method) and
then the two coats can be baked together or subjected to
forced drying. Basecoats prepared using the polyurethane
' ~``'~
h ~ a s
13
dispersions according to the invention give paint films
which are of substantially equal quality, regardless of
the baking or drying temperature, so that they can be
employed both as a refinish for motor vehicles and also
as a stoving enamel in the production-line finishing of
motor vehicles. Both applications result in paint films
having a good adhesion to both the substrate and the
original f`inish and having good resistance to humidity.
Furthermore, the brightness of the painted coat is not
impaired to any notable extent after a humidity test.
In the formulation of water-dilutable coating
materials using the polyurethane dispersions according to
the invention, it is possible to add the crosslinking
agents which are conventional in the paint industry, for
example, water-soluble or water-emulsifiable melamine or
benzoguanamine resins, polyisocyanates or prepolymers
having terminal isocyanate groups, water-soluble or
water-dispersible polyaziridines and blocked polyiso-
cyanates. The aqueous coating systems may contain all
known inorganic or organic pigments and/or dyes which are
conventional in paint technology, as well as wetting
agents, antifoams, leveling agents, stabilizers,
catalysts, fillers, plasticizers and solvents.
The polyurethane dispersions according to the
invention also may be used directly for joining any
desired substrates. In order to achieve specific
adhesive properties, the polyurethane dispersions
according to the invention can be blended with other
polymer dispersions or solutions as described above.
Furthermore, in order to improve the heat resistance and
peel strength it is possible to add crosslinking agents
such as, for example, polyisocyanates or prepolymers
having terminal isocyanate groups, or water-soluble or
water-emulsifiable melamine or benzoguanamine resins.
The adhesives which are based on the polyurethane
dispersions according to the invention may contain
additives which are conventional in adhesives technology,
such as plasticizers, solvents, film binder auxiliaries,
fillers and synthetic and natural resins. They are
' ~ ', ~ -.
2~3 ~9~S ` ~
".,,,
~- 14
specifically suitable for the production of adhesive
bonds between substrates in the motor vehicle industry,
for example, the adhesive bonding of interior fittings,
and in the shoe industry, for example, for joining the
sole of the shoe to the upper. The preparation and
processing of the adhesives based on the polyurethane
dispersions according to the invention are carried out by
the conventional methods of adhesives technology as are
employed for aqueous dispersion and solution adhesives.
10The invention is illustrated by the following non-
limiting examples.
Example 1:
An amount of 330.6 g of a polyester made from adipic
acid and 1,4-butanediol, having an OH number of 47.7, and
1517.6 g of neopentylglycol are placed together at 130C.
Amounts of 30.9 g of tolylene diisocyanate and 14.5 g of
m-tetramethylxylylene diisocyanate are metered into this
melt, which is stirred until the NCO value is 0.0%.
After cooling to 70C, 15.7 g of 1,6-hexanediol are added
and, once~ this has dissolved, a further 69.8 g of m-
tetramethylxylylene diisocyanate are metered in. At an
NCO value of 1.8~, 68.5 g of a 25% strength aqueous
solution of sodium taurinate are added and are stirred
into the resin. After about 10 min, a solution of 2.4 g
of ethylenediamine in 124 g of water is added and is
stirred in homogeneously while the temperature is raised
to 85C. After about 30 min, the mixture is diluted with
323.3`g of water to the final solids content (50%). A
dispersion is obtained which has a viscosity of 66 mPa.s,
a pH of 7.4, an amine number <0.3, and an acid number of
O . 9 .
Example 2~
An amount of 10.5 g of ethylene glycol is added to
330.6 g of a polyester made from adipic acid and 1,4
butanediol, having an OH number of 47.7. An amount of
41.2 g of tolylene diisocyanate is metered into this
solution whlle the temperature is raised from 60 to
213~3~5 ~ ;-
130C. As soon as the NCO value has reached 0.0%, the
melt is cooled to 70C and a further 8.2 g of ethylene
glycol are added. This solution is reacted further with
69.8 g of m-tetramethylxylylene diisocyanate. When an
NC0 value of 1.5% has been reached, 66 g of a 25%
strength aqueous solution of sodium taurinate are added
and are stirred in homogeneously. After about 10 min, a
solution of 1.1 g of ethylenediamine in 111.4 g of water
is metered in and is stirred in homogeneously over 30 min
while the temperature is raised to 85C. After this, the :
mixture -is diluted with 318.2 g of water to the final
solids content (50%). A dispersion is obtained which has
a viscosity of 253 mPa.s, a pH of 7.4, an amine number
<0.1 and an acid number of 0.9. ~ -
.
While several embodiments of the invention have been
described, it will be understood that it is capable of
further modifications, and this application is intended
to cover any variations, uses, or adaptations of the - -
invention, following in general the principles of the -
invention and.including such departures from the present ~--
disclosure as to come within knowledgP or customary
practice in the art to which the invention pertains, and
as may be applied to the essential features hereinbefore -~
set forth and falling within the scope of the invention. -
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