Note: Descriptions are shown in the official language in which they were submitted.
9~0
A process for preparing copolymers by polymerisation
of olefinically unsaturated diesters containing OH
groups with unsaturated monomers containing no free
COOH groups has already been proposed, wherein the
unsaturated diester used is a diester having two
hydroxyalkyl groups, obtained in a previous first
stage by reacting an anhydride of an olefinically
unsaturated dicarboxylic acid with a polyhydric alcohol,
to form a half-ester with free OH groups and further
reacting the half-ester, in a second step, with a
monoepoxide compound in the form of a glycidol, glycidyl
ether or glycidyl ester, and wherein the hardenable
reaction product thus obtained is isolated or is
cured by the action of a curing agent. The use of
the products manufactured by this method as hardenable
binders for lacquers and/or coatings is also described.
This process and the products manufactured
by the process have proved generally satisfactory.
However, there is a need to improve the process further.
This invention provides a process for the manufacture
of hardenable copolymers by polymerisation of unsaturated
esters with unsaturated polymerisable monomers which
do not contain any free COOH groups, wherein the
unsaturated ester used is an olefinically unsaturated
diester containing OH groups, which is obtained by
reacting an anhydride of an olefinica~ly unsaturated
dicarboxylic acid with a polyhydric alcohol and with
a monoepoxide compound, the olefinically unsaturated
diester containing OH groups being obtained beforehand
in a single stage by reacting an anhydride of the
olefinically unsaturated dicarboxylic acid, the poly~ydric
alcohol and the ~onoepoxide compound.
According to one ~articular embodiment o~ the
invention, the reaction product containing the diester
~ 9 ~
which has OH groups may be mixed with an organic solvent which is inert under
the reaction conditions, without any preliminary isolation of the diester,
then heated to the desired polymerisation temperature and then copolymerised,
in at least one further stage, with unsaturated polymerisable monomers,
preferably with the addition of polymerisation initiators and possibly chain
stoppers.
This invention simplifies the process considerably and saves not
only work but also energy.
Examples of dicarboxylic acid anhydrides for the preparation of
the diesters include the anhydrides of itaconic, citraconic, dimethylmaleic
acid, and preferably the anhydride of maleic acid.
Examples of alcohols which may be used include those listed
hereinafter.
Examples of epoxy compounds which may be used include alkylene
oxides, such as ethylene oxide or propylene oxide; glycidol; glycidyl ethers
of phenols, such as that of phenol itself, cresols or tert.-butyl-phenol;
glycidyl esters of saturated carboxylic acids; and preferably glycidyl esters
of branched fatty acids of general formula H2C~-&H-CH2-0-C-R,
O O
wherein R is the radical of a fatty acid branched in the ~-position, said
acid having 8 to 16, preferably 4Be to 12 carbon atoms.
The molecular weight of the diesters is generally within the
range of 250 to 1500, preferably 400 to 1250 and the OH number is within
the range 280 to 450.
The temperature at which the diester formation is effected is
generally 50 to 200, preferably 100 to 170C.
Copolymerisation of the intermediate products may be effected
in one or more, but preferably two, steps, generally at 80 to 220, preferably
130 to 170, more particularly 140 to 160C, possibly without
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`11599!~
the co-use of solvents. It may be effected thermally.
Preferably, however, copolymerisation is carried
out in the presence of catalysts, especially radical
initiators, more particularly peroxides, e.g. di-
S tert.-butylperoxide, dibenzoylperoxide, cumyl hydro-
peroxide and azo compounds such as azo-bis-isobutyro-
nitrile or the like. It is appropriate to use solvents
or diluents, which may be put in first. Examples
of solvents which may be used include high-boiling
aliphatic and/or aromatic solvents having a boiling
point of from 140 to 185C, such as mineral oils
having a boiling point of 160 to 180~C, xylenes,
butyl acetate, ethyleneglycol acetate monoethyl ether
or the like. If desired, the copolymerisation may
also be effected in the presence of chain stoppers
such as, for example, alkanethiols such as n-dodecyl-
mercaptan, in order to control the molecular weight.
Examples of copolymerisable monomers which
may be employed include aromatic vinyl compounds,
such as styrene, a-methylstyrene, the various vinyl-
toluenes and divinylbenzenes (although the latter
are generally only used in minor amounts); alkyl
acrylates or methacrylates with 1 to 6, preferably
1 to 4 carbon atoms in the alkyl group, such as methyl,
ethyl, n- or iso-propyl, n-, sec-, iso- or tert.butyl,
the various pentyl and hexyl acrylates or methacrylates;
and hydroxy esters with 2 to 6 carbon atoms, such
- as hydroxyethyl or hydroxypropyl acrylate and methacrylate,
again either individually or in admixture. If polymer-
isation is effected with a monomer mixture, thismixture appropriately contains at least 10 mol-%
and preferably not more than 70 mol-% of aromatic
vinyl compounds, preferably styrene and/or not more
than 20, preferably not more than 10 weight ~ o~ hydroxy-
alkyl ester, based on the total monomer mixture.
Copolymerisation is appropriately continueduntil there is a conversion of at least 9~, preferably
-- 4 --
at least 98%.
In a preferred embodiment o the process according
to the invention, a copolymer is prepared from
a) 10 to 60 weight % ofadicarboxylic acid ester,
preferably based on maleic anhydride, trimethylolpropane
and a glycidyl ester of a branched fatty acid with
8 to 16, preferably 10 to 12 carbon atoms,
b) 5 to 50 weight% of an ester of acrylic and/or methacrylic
acid with a monohydric alcohol with 1 to 6, preferably
1 to 4 carbon atoms,
c) 5 to 70 weight ~ of styrene, and
d) 0 to 20 weight~ of an ester of acrylic and/or methacrylic
acid with a dihydric alcohol with 2 to 6, preferably
2 to 4 carbon atoms.
The polyhydric alcohols which may be used as
components of the acrylic or methacrylic acid esters
are the same ones which may be used for the preparation
of the half esters, namely, for example, diols such
as ethyleneglycol, propanediol-1,2, propanediol-1,3,
the various butane-, pentane- and hexanediols, such
as butanediol-1~4, hexanediol-1,6, neopentylglycol,
diethyleneglycol and dipropyleneglycol. It is also
possible to use reaction products of polyols, such
as, ~or example, glycerol, trimethylolethane and
-propane, pentaerythritol, dipentaerythritol with
isocyanate compounds or carboxylic acids, e.g. pentaery-
thritol diesters with monocarboxylic acids, provided
- that they contain two free OH groups per molecule.
The acid number of the copolymers may be from
2 to 20, for example, and the OH number may be, for
example, from 50 to 200.
The scope of the invention also extends to
the curing of the copolymer, for which various curing
agents may be used, namely, for example, masked or
free polyisocyanates, polycarboxylic acids, preferably
in the form of anhydrides, amine resins and phenolic
resins. Examples of polyisocyanates include di-
to tetravalent isocyanates, such as toluylene diisocyanate,
7 = ~
9~
5 --
isophorone diisocyanate, hexamethylene diisocyanate,
2,4,6-triisocyanatotoluene, 4,4',4"-triisocyanato-
triphenylmethane, 2,4,~'-triisocyanato-diphenylmethane,
2,2',5,5'-tetraisocyana~o-diphenylmethane and also
trivalent isocyanates, which may be obtained, for
example, by the addition of trimethylol propane to
toluylene diisocyanate, a triisocyanate which may
be prepared by reacting hexamethylene diisocyanate
and water, or isocyanates with up to 4 free isocyanate
qroups, such as may be obtained, for example, by
reactinq toluylene diisocyanate and hexamethylene
diisocyanate, or the masked products thereof with
acetoacetic acid esters, for example, such as those
of methanol, ethanol, propanols or butanols, or with
E-caprolactam.
Examples of polycarboxylic acid hardeners which
may be used include maleic acid, succinic acid, adipic
acid, phthalic acid, trimellitic acid, pyromellitic
acid or anhydrides of these acids, as well as low
molecular oligomeric esters or polyesters with free
COOH groups ~ If desired, a catalyst may also be
added, preferred catalysts being organic metal compounds,
such as dibutyl-tin dilaurate, dibutyl-tin oxide,
cobalt naphthenate or octoate; or amines such as
ethylene diamine and the homologues thereof, such
as diethylene triamine, tetraethylene pentamine,
terti~ary amines, such as triethylamine, tributylamine,
dimethylaniline; but~ particularly alkanolamines,
such as diethylethanolamine.
Instead of individual components, mixtures
may also be used in all these cases.
- The hardening, particularly with polyisocyanates,
may be carried out at ambient temperature. At elevated
temperatures, it is predominantly the other above-
mentioned hardeners, including masked isocyanates,
which are used, whilst the amine and phenolic resins
may also act as hardeners, for example, in the presence
~f acids, such as toluenesulphonic acid. The thermal
3~3~0
6 --
hardeniny is generally effected within 10 to 30 minutes
at 120 to 200C. The addition of catalysts, e.~.
metal compounds such as dibutyl-tin dilaurate and/or
amines, such as tertiary alkanolamine, e.g. diethylethanol-
amine, may be particularly advantageous when isocyanatesare used.
The hardenable binder may also be combined
with conventional pigments, fillers and/or additives.
Even if the products obtained according to
the invention contain only a minor proportion of
hydroxyalkyl esters of unsaturatèd acids, or even
none at all, once they are cured with the curing
agents, hardened coatings are obtained which are
at least e~uivalent to the known coatings based on
acrylate resins containing hydroxyalkyl esters, but
in general the coatings accordin`g to ~he invention
are surprisingly superior in their technical coating
properties. Thanks to the greater possibility of
variation and choice of reaction partners in the
production of the copolymers, this invention makes
it possible to select the optimum systems for the
purpose intended. Moreover, the solubility of the
polymers is improved by the incorporation of the
groups of unsaturated dicarboxylic acids, such as
maleic acid esters, in the acrylate-containing systems.
As a result, solvent-containing systems can be produced
having a higher solids content than was possible
- with the acrylate resins used hitherto, and the systems
are therefore environmentally more acceptable.
The products obtained according to the invention
may be used for paints and/or coatings for external
use and for linings, and also, for example, as a
corrosion proofing for various objects, particularly
those which are exposed to atmospheric influences,
such as in building construction, vehicles and vehicle
parts, e.g. bodywork, and for domestic appliances
and electrical equipment and components thereof.
They have good adhesion properties to substrates
-- 7 --
consisting of plastics and metals, such as copper,
brass, zinc or iron alloys. Moreover, they have
good flow qualities when applied as coatings. The
hardened coatings are distinguished by a high gloss,
good elasticity, very good weathering resistance
and colour stability. The products obtained according
to the invention which are hardenable at ambient
temperature are particularly suitable for coating
construction materials, preferably flooring, e.g.
based on cement and concrete. Moreover, the products
obtained according to the invention are suitable
for use as adhesives, having the advantages of good
solubility and consequently a greater solids content.
The following non-limiting Examples serve to
lS illustrate the invention. In the examples ~ refers
to weight % and T refers .o parts by weight.
1~9990 `
-- 8 --
Examples 1) to 3)
Maleic anhydride, trimethylolpropane and the
glycidyl ester of a fatty acid` with 10 carbon atoms
branched in the -position are heated to 100C, with
5 stirring. After a short time, the internal temperature
ri~es to 140C, but after about 30 minutes it falls
again. The acid number of the reaction mixture is
then 20. It is mixed with the desired solvent or
mixture of solvents (e.g. xylene, mixtures of aromatics
with a boiling point of 165 to 175C, butyl acetate)
and heated to the desired polymerisation temperature
(e.g. 140C). At this temperature, first of all
a mixture of styrene, initiator and, optio~ally chain stopper
are added over 3 hours and then a mixture of one
or more methacrylic acid esters, styrene, initiator
and chain stopp~ are uniformly added over 3 hours.
The mixture is left to polymerise for a further 2
hours at 175C.
The reaction components and the proportions
used are shown in thè Table which follows:-
- 9 -
Example 1 2 3
Maleic anhydride 5.3 4.6 4.0
Trimethylolpropane - 7.3 6.3 5.4
Glycidyl ester 13.3 11.7 10.0
Xylene 20 20 20
Alkyl-aromatic mineral oil*) 10 10 10
Butyl acetate 10 10 10
Styrene 16.1 16.1 16.1
Di-tert-butylperoxide 0.3 0.3 0.3
Dodecyl mercaptan 0.2 0.2 0.2
Hyd`roxyethyl methacrylate - 2.7 5.4
Methyl methacrylate 12.1 12.7 13.2
Styrene 4.9 4,9 4.9
Di-tert-butylperoxide 0.3 0.3 0.3
Dodecyl mercaptan 0.2 0.2 0.2
Polymerisation temperature (C) 140 140 140
Solids content % (1 hour
at 125C) 59.6 60.5 60.5
Quantity of acid (mg KOH/g
20 solid resin) 6 6 6
Hydroxyl number (mg KOH/g
solid resin) 150 155 155
Viscosity mPa.s (50% in xylene) 740 ô80 lOôO
Colour number
-25 *) Boiling range 160 to 165C.
1~i9990
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Preparation of coatinq compositions
Coating compositions having the following composition
are prepared from the solutions of the copolymers:
Example 1 2 3
Copolymer solution 70.80 69.52 69.52
Dibutyl tin dilaurate
~1% in xylene) 0.23 0.23 0.23
Diethylethanolamine 0.38 0.38 0.38
Silicone oil (1% in xylene) 1.00 1.00 1.00
10 Reaction product of hexamethylene
diisocyanate and water (75% in
ethyleneglycol monoethyl ether
acetate) 27.59 28.87 28.87
The polymer solutions are adjusted to a viscosity
(DIN 53211/20C) of 45s by the addition of a mixture
of solvents consisting of xylene, an aromatic mixture
of hydrocarbons (boiling range 165 to 175C), butyl
acetate and ethyleneglycol monoethyl ether acetate
(weight ratio 40:25:20:15), and then the solutions
are applied in a wet layer thickness of lOO~um to
sheets of glass and sheet steel. The films are dried
in the air at ambient temperature.
0`
Technical tests on the coatings
Example ` 1 2 3
Dry so that no dust adheres, min. 21 18 20
Tbuch-Dry, min. 120 120 120
Pendulum hardness according
to Kanig, DIN 53157 after
24 hours 85 80 77
Er ichsen cupping DIN 53156 `
af ter 10 days 8 . 8 8. 8 8 . 5
Resistance towards gasoline, min.
after 10 days ~30 ~30 ~30
Solids content %
(1 hour at 125C) Sl.3 51.8. 50.5
