Note: Descriptions are shown in the official language in which they were submitted.
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Ionic polymers
Field of the Invention
This invention relates to ionic polymers obtainable from
polyvalent ions and polybasic carboxylic acids and to their production
and use.
Background of the Invention
Ionic polymers are polymers containing ionic groups as parts of
the main chain or laterally thereof. Depending on the ion content, they
may be divided into polyelectrolytes and ionomers. Polyelectrolytes have
a high percentage ion content and are generally soluble in water,
io examples being polymethacrylic acid or polyacrylic acid. By contrast,
ionomers are generally insoluble in water on account of their largely
apolar main chain and their relatively small content of ionic groups.
Known ionomers are polyacrylates, polyurethanes and, in particular,
thermoplastic copolymers of ethylene with carboxyfunctional monomers,
is particularly methacrylic acid, which are partly present as salts of sodium,
potassium, magnesium or zinc. By virtue of the ionic bond, they are
thermo-reversibly crosslinked. They are used, for example, as films for
packaging and coating materials and inter alia as self-adhesive films.
It is also known to the expert that carboxyl-group-stabilized
2o dispersions (anionic dispersions) can readily coagulate in contact with
polyvalent dissolved cations (for example Ca2+, Zn2+, AI3+, etc.) because
insoluble carboxylate salts eliminate the emulsifier effect. This principle
is used to improve dispersions containing carboxyl groups in the water
resistance and non-tackiness of the films by complexed Zn or Zr ions
2s after drying and evaporation of the ligand (see, for example, EP 0 197
662, DE 23 37 606, DE 38 00 984). Accordingly, ion-compatible
dispersions are generally cationically or nonionically stabilized.
In addition, it is known from works of Matsuda and
Kothandaraman (see, for example, H. Matsuda, Journal of Polymer
3o Science 12, 455-468 (1974); H. Kothandaraman, Polymer Bulletin 13,
353-356 (1985)) that special short-chain OH-terminated compounds
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containing a carboxyl group prepared in solvents change their properties,
for example their melting point, by dimerization with divalent salts. After
dissolution in organic solvents, these solids bridged by polyvalent ions
can be reacted with aromatic or aliphatic diisocyanates to form glass-like
s polymers.
However, there is no document in the prior art which describes
oligomers processable in particular at room temperature to give useful
performance properties simply by linking individual fat- and oil-based
oligomer structural units by salt bridges of polyvalent ions.
io Hitherto, the need for ecologically safer products in such fields
as sealants, coatings (for example lacquers and paints), adhesives,
plastics processing and fire prevention, which has arisen out of the
increase in environmental awareness, has only been partly satisfied.
Both organic solvents and residual monomers or chlorine-containing
is polymers have to be replaced by alternative systems. Thus, polymers
dissolved in organic solvents have been increasingly replaced, for
example, by aqueous polymer dispersions in the past few decades.
Products such as these cure or set through evaporation of the liquid
phase which can or does give rise to a considerable shrinkage in volume
2o and, in the case of water-based systems, to a marked dependence of the
drying time on climatic conditions.
In addition to systems which already contain preformed
polymers to establish the final properties, there are also reactive systems
based on monomers or oligomers which cure by chemical reaction of 1
2s or 2 components. Cyanoacrylates, NCO-terminated polyurethanes,
which set or crosslink under the effect of moisture, or 2-component
epoxides and polyurethanes are well known to the expert. Like 1-
component reactive systems, 2-component product formulations
consisting of resin and catalyst often contain highly reactive, toxicologi-
3o cally unsafe monomers or residual monomers or form unwanted
decomposition products in use - a fact which generally has to be
communicated to the consumer by warnings (on labels).
Advantages of reactive systems include, for example, their
relatively low starting viscosity (the high molecular weight polymers are
ss only formed during the curing process) and the possibility of obtaining
100% systems with no significant shrinkage in volume. It would be
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extremely desirable to utilize the advantages of known 1- and 2-
component reactive systems, but at the same time to be able to resort
to toxicologically safer and environmentally more compatible starting
monomers or oligomers.
Summary of the Invention
It has now surprisingly been found that toxicologically
substantially safe carboxylic acids which are liquid or can still be spread
at the application temperature, more particularly room temperature, cure
io under the effect of polyvalent ions and, optionally, moisture to give high
performance polymer structures ("ionic curing"). Materials of corre
sponding structure which are highly viscous or solid or cannot be spread
at room temperature may be internally hardened on the same principle,
as known for example from hotmelt adhesives post-curing through
is isocyanate crosslinking.
Accordingly, the present invention relates to ionic polymers
obtainable from carboxylic acids, or reactive derivatives thereof, and
polyvalent metal ions, the carboxylic acids in turn being obtainable by
chemical modification of fats and oils and having a molecular weight of
Zo at least 200 for at least 70% by weight of said carboxylic acids. The
fats or oils or derivatives produced from them may be of both vegetable
and animal origin or, optionally, may be selectively synthesized by
petrochemical methods.
2s Detailed Description of the Invention
Suitable carboxylic acids are representatives of all oil- and fat-
based raw materials which, on average, contain at least one and
preferably 1 to 10, more preferably 2 to 5 carboxylic acid groups per
oligomer molecule or which can release these carboxylic acid groups by
3o reaction with water. They may be obtained, for example, by ene
reactions, transesterifications, condensation reactions, grafting ffor
example with malefic anhydride or acrylic acid, etc.) and, for example,
epoxidations with subsequent ring opening. Basic oleochemical
reactions such as these may preferably be carried out on fats and oils
3s containing double bonds and/or OH groups, for example on fats and oils
from rape (new), sunflowers, soybeans, linseed, coconuts, oil palms, oil
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palm kernels and olive trees. Preferred fats and oils are, for example,
beef tallow with a chain distribution of 67% oleic acid, 2% stearic acid,
1 % heptadecanoic acid, 10% saturated C,Z_,B acids, 12% linoleic acid
and 2% saturated > C,8 acids or, for example, the oil of new sunflowers
s (NSf) which consists of approx. 80% oleic acid, 5% stearic acid, 8%
linoleic acid and approx. 7% palmitic acid.
Ene reactions are carried out, for example, with anhydrides on
unsaturated fats and oils at elevated temperature. Epoxidations of
double bonds and subsequent ring opening, for example with amines,
io aminoalcohols, alcohols, diols, polyols, hydroxycarboxylic acids or
polycarboxylic acids, provide access, for example, to the fat- and oil-
based starting materials required containing acid or anhydride groups.
The fatty acids used for these reactions may also be hydrolysis products
of the fats and oils containing unsaturated groups or OH functions.
is Other reactions such as, for example, simultaneous or subsequent
condensation or transesterification reactions can lead to a further
increase in the molecular weight of the COOH-terminated fat- and oil-
based structural elements. The degree of oligomerization or the
molecular weight and nature of the starting materials should be selected
2o according to aspects generally known to the expert so that the resulting
oligomer can be spread or processed at the corresponding processing
temperature (for example even room temperature).
Suitable polyvalent metal ions - preferably in the oxidation state
+2 to +4 - are any of the ions which form poorly soluble complexes
2s with carboxyl groups, as known for example from metal soaps.
Preferred cations are Ca, Be, Mg, AI, Zn, Sr, Cd, Ba, Hg, Sn, Zr, Pb, Ti,
V, Cr, Co, Mn, Cu, Bi, Fe and Ni. Of these, Mg, Ca, AI, Sn and Zr are
particularly suitable. The monovalent metal ions Li, Na, K, Cu, Rb, Ag,
Cs - preferably Li, Na, K - may also be used in stoichiometric quantities
30 of up to 65% and preferably 30%, based on the total content of cations.
In principle, suitable counterions are any organic and inorganic anions
such as, for example, halogens, more particularly F and CI, nitrides,
nitrates, sulfites, carbonates, hydrogen carbonates, chlorates, per-
chlorates, hydroxides, oxides, formates, acetates and propionates and
3s hydrates thereof. Preferred embodiments contain hydroxides, hydrated
oxides, oxides and/or carbonates, more particularly aquoxides.
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Aquoxides are understood to be any compounds of polyvalent metals
which can be experimentally or formally derived from oxide and water,
i.e. hydroxides, hydrated oxides or oxide aquates.
Up to 90% by weight, preferably up to 40% by weight and,
s more preferably, up to 20% by weight of salt is added.
The new formulations according to the invention consist of a
fine-particle suspension of salts of polyvalent metal ions and, optionally,
additives or salts showing a slightly alkaline reaction in a carboxy-
functional oligomer. The salts required may be present in free form or
io may be adsorbed, for example, on surfaces (for example aluminium
oxide, silica gel or clays), dissolved or microencapsulated, for example
to improve particle fineness or to enable the reaction to be retarded to
a certain extent.
In addition, commercially available mortars, gypsums and
is cements containing Ca, Mg, AI or Fe ions are also suitable as potential
cation donors. In this case, the claimed ionic polymers are produced by
application of the carboxylic acids or anhydrides to a substrate already
containing the polyvalent metal ions. In this case, both curing mecha-
nisms (setting of the mortars, gypsums and cements and crosslinking of
2o the carboxylic acids) may come into play at the same time so that the
final properties of the formulations can be tailored over a very wide
range by varying the concentrations of the individual components.
The carboxyfunctional fat- and oil-based formulations produced
in accordance with the invention can be cured not only with up to a few
2s percent of the salt-containing mortars, gypsums, cements, etc., but also
vice versa: the inorganic materials may be modified (for example
hydrophobicized or elasticized) by addition of a few percent of oligomers
liquid at room temperature.
The reaction between the metal salts and the COOH-terminated
30 oleochemical raw materials may be catalyzed by the same catalysts
which are used, for example, in the production of soaps. In addition to
the amines preferably used, OH-functional raw materials such as, for
example, glycerol, polyols, sorbitol, sugars are also suitable. In addition,
OH groups fixed to the oleochemical raw materials also catalyze the
as reaction.
The components "carboxylic acid" and "metal ions" may be
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present both separately (two-component formulation) and also in
combination (one-component formulationl. In the two-component
formulation, the polyvalent salts should either be applied to the substrate
beforehand from aqueous solution (primer), already present in the
s substrate (for example mineral substrates) or stirred in. The salts should
be finely suspended. Relatively high particle fineness increases the
curing rate. If the salt-like compounds and the fat- and oil-based
carboxyfunctional starting materials are present in combination (one-
component formulation), setting may be initiated either by increasing the
io temperature or by exposure to moisture. Moisture-curing systems are
based, for example, on structures which only develop the carboxyl
groups after a preliminary reaction with water (for example anhydride-
containing fat- and oil-based raw materials).
Difunctional COOH-terminated oligomer structural units lead
is ideally to linear structures, particularly with divalent ions;
trifunctional (or
even more than trifunctional) COOH-terminated oligomer structural units
lead to crosslinked structures in the same way as difunctional structural
units with trivalent ions while monovalent ions act as chain terminators.
The composition of the oligomer molecules in regard to their poly
2o functionality is selected so that the optimal properties are achieved for
the application envisaged. Highly elastic films should preferably be
based on linear structures. High-strength compositions may contain
crosslinking units, as also known to the expert. To improve the
mechanical properties of the ionically bridged structural units, the
2s molecular weight of the carboxylic acid should be greater than 200 and
preferably greater than 400 while the degree of conversion of the
oleochemical raw materials should not be too high, i.e. should be less
than 1:2 and preferably less than 1:1.5, expressed as equivalents of
COOH to the valency of the metal. The molecular weight of the
3o carboxylic acid can be measured by means which include ebulliometry,
cryoscopy, and membrane osmometry. Each of the measurements will
yield a number average molecular weight as opposed to a weight
average molecular weight. Because the carboxylic acids will typically
have a low polydispersity, the weight average molecular weight will
35 typically be essentially the same as the number average molecular
weight.
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Short-chain polybasic acids having molecular weights below
200 such as, for example, oxalic acid, adipic acid, malefic acid, phthalic
acid, sebacic acid, malonic acid, succinic acid, glutaric acid, manic acid,
tartaric acid, citric acid or their anhydrides may also be used in quantities
s of less than 30% and preferably less than 10%.
Plastic formulations containing a few percent (less than 40%)
of the described ionically bridged polymers for modification or formula-
tions containing a few percent (less than 40%) of other plastics, for
example copolymers of ethylene and vinyl acetate, polyamide, polyester,
io polyurethane, polyacrylate, etc., are also possible.
The acids based on oleochemical structural units which are
linked in particular by polyvalent ions may also be further processed to
dispersions using internal emulsifiers, for example neutralized unreacted
COOH groups, and/or external emulsifiers of nonionic and anionic
is character. External emulsifiers may be both low molecular weight
compounds and also polymers. Emulsifiers or surfactants such as these
are known to the expert and are described in numerous reference books
(see, for example, Tensid-Taschenbuch, Dr. Helmut Stache, 2nd Edition,
1981, Carl Hanser-Verlag, Munchen/
2o Wien, more particularly pages 771 to 978).
In addition, anionic or nonionic stabilized polymer dispersions
(for example acrylates or polyurethanes) may also be added as emulsifi-
ers, the emulsifying effect being known to increase with increasing
hydrophilicity. Protective colloids (for example starch, starch deriva-
2s tives, cellulose derivatives, polyvinyl alcohols, etc.) as used in the
production of polymer dispersions (for example polyvinyl acetate +
copolymers) may also be added. In formulations, the dispersions thus
prepared containing ionically bridged acids may also be mixed with
commercially available dispersions, anionically and nonionically stabilized
3o dispersions having the best stability.
The polymer structures according to the invention are also
distinguished by a flameproofing effect. The elimination of C02
catalyzed by the metal salts or the elimination of water with increasing
temperature may be responsible for this effect.
35 The invention is illustrated by the following Examples.
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Examples
A1 Rigid com~~ound
Example 1
1 Mol Dt-Do 1447 (reaction product of fully epoxidized soybean
oil with dimer fatty acid in a ratio of 1:1, based on 1 mol dimer fatty acid
per epoxide group) is reacted with 1 mol Ca(OH)2 at 30°C. A rigid
elastic compound is obtained after 48 hours.
to Example 2
1 Mol Dt-Do 1448 (reaction product of fully epoxidized soybean
oil with dimer fatty acid, 0.8 mol dimer fatty acid per epoxide group) is
reacted with 1.5 mol Mg0 at 25°C. A rigid compound is obtained after
24 hours.
Example 3
1 Mol Dt-Do 1498 (reaction product of fully epoxidized linseed
oil epoxide with dimer fatty acid, 1.5 mol dimer fatty acid per epoxide
group) is mixed with 1 mol Mg0 and 0.2 mol glycerol at 25°C. A solid
ao but elastic compound is obtained after 1 hour.
BI Tacky compound
Example 4
1 Mol Dt-Do 1447 is reacted with 0.65 mol Mg0 for 20
a5 minutes at 80°C. A non-flowing tacky mass is obtained after cooling.
CI Elastic compound
(Polyionizates with polymer additions to improve the mechanical
properties)
3 o Example 5
After reaction with 1.5 parts by weight MgO, 80 parts by
weight Dt-Do 1448 are reacted with 20 parts by weight Luviskol K 3(~
(polyvinyl pyrrolidone, a product of BASF) at 140°C. An elastic, tacky
compound is obtained after cooling.
Example 6
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After reaction with 2.5 parts by weight Mg0 and 1 part by
weight ZnO, 60 parts by weight Dt-Do 1347 (reaction product of 2 mol
stearic acid methyl ester epoxide with 1 mol ethylene glycol and
subsequent ester hydrolysis to the glycol-bonded dicarboxylic acid) are
s reacted with 40 parts by weight Escorene UL-05540 (ethylene/vinyl
acetate copolymer) at 150°C. An elastic transparent compound - which
is also suitable as a hotmelt adhesive - is formed after cooling.
D) Plastic compound (kneading compound)
Example 7
l0 24.8 Parts by weight Dt-Do 1347 are reacted with 1 part by
weight Mg0 at 30°C and 74.5 parts by weight chalk (Wical, a product
of Grunsiegel) are incorporated in a kneader. The compound formed can
be kneaded and molded by hand and is suitable as a permanently plastic
sealant.
E) Moisture-curing systems
Example 8
90 Parts by weight Stru-DH 4844 (reaction product of malefic
anhydride/sunflower oil (3:1 ) stirred under nitrogen for 6 hours at
ao 210°C) and 10 parts by weight Mg0 are mixed.
The mixture obtained, which is stable in storage for at least 3
months, is applied to a substrate (glass plate) in the form of a film (layer
thickness 0.2 mm) and cures complete in 24 to 48 hours. This coating
compound is also suitable for moist substrates where curing can take
place more quickly.
Example 9
2% Water is added to the mixture of Example 8. After
homogenization, exothermic curing takes place in a few minutes. Films
of the cured material are no different from those of Example 8.
F) Dispersions
Example 10 (Comparison Example with Example 1 1 )
Dt-Do 1447 was stirred into cold H20 and 60% neutralized with
3s NaOH. A fine-particle, extremely tacky dispersion (solids content 35%)
with high adhesive transfer is obtained and cannot be used as a contact
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adhesive (tensile shear strengths on beechwood 0.03 N/mm2, 10 cm2
overlap). In other words, large quantities of adhesive remain on the two
surfaces when the bond is broken.
s Example 11
Dt-Do 1447 was 65% bridged with MgO, based on the
carboxyl groups, and stirred at 100°C into water heated to 90°C
which
contains the corresponding quantity of NaOH required to neutralize the
remaining 35% carboxyl groups. A white dispersion (solids content
l0 40%) with tensile shear strengths on wood of 3 N/mmz was formed.
Example 12
The reaction with Mg0 was carried out as in Example 1 1 and,
at the same time, 20 parts by weight balsam resin were added to the
is melt at 100°C. During dispersion, the NaOH content was increased so
that the carboxyl groups of the balsam resin were also neutralized. A
homogeneous dispersion with tensile shear strengths on wood of 5.0
N/mm2 was obtained.
a o Example 13
A dispersion was prepared as in Example 1 1, the water
containing 30%, based on the solids content of the ionically bonded melt
component, of the fine-particle polyurethane dispersion Pritt Alleskleber
(a product of Henkel KGaA, anionic PUR dispersion based on isophorone
25 diisocyanate, polytetrahydrofuran and dimethylol propionic acid,
neutralized with NaOH, solids content 35%) before dispersion. The
dispersion obtained had a solids content of 38% and tensile shear
strengths on wood of 4 N/mm2.
3o Measurement of tensile shear strength
Tensile shear strength was measured on test specimens
measuring 10 x 5 x 0.5 cm3 at a crosshead speed of 10 cm/min. The
test specimens were stored for 3 days at room temperature after
bonding. The overlap of the test specimens was 2 cm x 5 cm (bonded
35 surface). This test was developed in accordance with DIN 53254.
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