U.S. patent number RE39,746 [Application Number 10/853,763] was granted by the patent office on 2007-07-31 for phosphoric esters and their use as dispersants.
This patent grant is currently assigned to Goldschmidt GmbH. Invention is credited to Tammo Boinowitz, Eberhard Esselborn, Arno Knebelkamp, Christian Psiorz, Stefan Silber, Stefan Stadtmuller, Ellen Wallhorn.
United States Patent |
RE39,746 |
Boinowitz , et al. |
July 31, 2007 |
Phosphoric esters and their use as dispersants
Abstract
The invention relates to phosphoric esters of the general
formula I ##STR00001## where X is 1 or 2; n is from 2 to 18; m and
o are each from 2 to 100; k is from 2 to 4; R'' is H or a linear or
branched alkyl radical; and R' is an alkyl, alkaryl, alkenyl, or
sulfopropyl radical, and to there use as dispersants for pigments
and fillers in aqueous or organic media.
Inventors: |
Boinowitz; Tammo (Essen,
DE), Esselborn; Eberhard (Essen, DE),
Knebelkamp; Arno (Muhlheim, DE), Psiorz;
Christian (Dusseldorf, DE), Silber; Stefan
(Krefeld, DE), Stadtmuller; Stefan (Essen,
DE), Wallhorn; Ellen (Bochum, DE) |
Assignee: |
Goldschmidt GmbH (Essen,
DE)
|
Family
ID: |
7858296 |
Appl.
No.: |
10/853,763 |
Filed: |
May 25, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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09251966 |
Feb 17, 1999 |
6310123 |
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Reissue of: |
09829799 |
Apr 10, 2001 |
06423130 |
Jul 23, 2002 |
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Foreign Application Priority Data
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Feb 19, 1998 [DE] |
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198 06 964 |
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Current U.S.
Class: |
106/476; 106/503;
516/199; 516/33; 516/34; 516/77; 516/81; 516/90; 516/908; 516/93;
524/115; 524/136; 524/141; 524/513; 524/522; 525/333.3; 525/340;
526/932; 558/186 |
Current CPC
Class: |
B01F
17/0064 (20130101); C07F 9/091 (20130101); C08G
18/3885 (20130101); C09B 67/0089 (20130101); Y10S
526/932 (20130101); Y10S 516/908 (20130101) |
Current International
Class: |
C08K
5/372 (20060101); B01F 17/14 (20060101); B01F
3/12 (20060101); C07F 9/09 (20060101); C08K
5/52 (20060101) |
Field of
Search: |
;558/186,92,110,114
;516/13,24,34,57,199,908,33,77,78,90,93,81 ;106/476,503
;524/115,136,141,494,513,522 ;525/340,333.3 ;528/393 ;526/932 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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58-100194 |
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Jun 1984 |
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JP |
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59-100194 |
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Jun 1984 |
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JP |
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Other References
Eastman Laboratory Chemicals (Eastment Chemical Co., Laboratory and
research Products, Rochester, NY) pp. 919 and 977, Apr. 1994. cited
by examiner .
DWPI on West, week 198429, London: Derwent Publications Ltd., AN
1984-179609 JP 59100194 A (Kao Corp.), Abstract, 1984. cited by
examiner .
Martin Mosquet et al., "Polyoxyethylene Di-Posphonates as Efficient
Dispersing Polymers to Aqueous Suspensions", Journal of Polymer
Science, vol. 65, pp. 2545-2555 (1977), month unavailable. cited by
examiner .
TBK Trading, LLC on the World Wide Web at
http://www.tbktrading.com/FAQ.htm#Dye%20and%20a%20Pigment (Apr.
2005) pp. 1-3. cited by examiner.
|
Primary Examiner: Metzmaier; Daniel S.
Attorney, Agent or Firm: Scully, Scott, Murphy &
Presser, P.C.
Parent Case Text
RELATED APPLICATIONS
The present application is a divisional application of U.S.
application Ser. No. 09/251,966, filed Feb. 17, 1999, now U.S. Pat.
No. 6,310,123.
Claims
What is claimed is:
.[.1. A phosphoric ester having the formula: ##STR00005## x is 1 or
2, n is a number from 2 to 18, m and o are each a number from 1 to
100, k is a number from 2 to 4, and R'' is H or a linear or
branched alkyl radical. R' is an alkyl, alkaryl, alkenyl or
sulfopropyl radical..].
2. The .[.phosphoric ester.]. .Iadd.pigment preparation .Iaddend.of
claim .[.1.]. .Iadd.18 .Iaddend.wherein the ratio of m/o is from
1:10 to 10:1.
3. The .[.phosphoric ester.]. .Iadd.pigment preparation .Iaddend.of
claim .[.1.]. .Iadd.18 .Iaddend.wherein the ratio of m/o is from
1:2 to 10:1.
.[.4. The phosphoric ester of claim 1 wherein the average molecular
weight is from 300 to 15,000 g/mol..].
.[.5. The phosphoric ester of claim 1 wherein the average molecular
weight is from 500 to 5000 g/mol..].
6. The phosphoric ester of claim .[.1.]. .Iadd.17 .Iaddend.wherein
R''=H.
7. A method of forming a dispersion comprising dispersing a
phosphoric ester of claim .[.1.]. .Iadd.17 .Iaddend.with one or
more pigments or fillers in an aqueous or organic medium.
8. The method of claim 7 wherein R''=H.
9. A method of forming a highly filled sheet molding compound or
bulk molding compound, comprising dispersing components of a
molding compound and a phosphoric ester as of claim .[.1.].
.Iadd.17.Iaddend..
10. The method of claim 9 wherein R''=H.
.[.11. A pigment preparation comprising one or more organic or
inorganic pigments and from 1 to 100% by weight, based on the
pigments, of a dispersing additive having the formula: ##STR00006##
x is 1 to 2, n is a number from 2 to 18, m and o are each a number
from 2 to 100, k is a number from 2 to 4, and R'' is H or a linear
or branched alkyl radical..].
12. The pigment preparation of claim .[.11.]. .Iadd.18
.Iaddend.wherein R''=H.
.[.13. An aqueous paste comprising one or more organic or inorganic
colorants and from 1 to 100% by weight, based on the colorants, of
a dispersing additive having the formula: ##STR00007## x is 1 to 2,
n is a number from 2 to 18, m and o are each a number from 2 to
100, k is a number from 2 to 4, and R'' is H or a linear or
branched alkyl radical..].
14. An aqueous paste of claim .[.13.]. .Iadd.19 .Iaddend.wherein
R''=H.
.[.15. A carbon black paste comprising from 10 to 100% by weight,
based on the weight of carbon black, of a dispersing additive
having the formula: ##STR00008## x is 1 or 2, n is a number from 2
to 18, m and o are each a number from 2 to 100, k is a number from
2 to 4, and R'' is H or a linear or branched alkyl radical..].
16. A carbon black paste of claim .[.15.]. .Iadd.20
.Iaddend.wherein R''=H.
.Iadd.17. A phosphoric ester having the formula: ##STR00009## x is
1 or 2, n is a number from 2 to 18, m and o are each a number from
2 to 100, k is a number from 2 to 4, R'' is H or a linear or
branched alkyl radical, R' is an alkyl, alkaryl, alkenyl or
sulfopropyl radical, and with the proviso that when R= ##STR00010##
the average molecular weight of said phosphoric ester is not more
than about 2184 g/mol..Iaddend.
.Iadd.18. A pigment preparation comprising one or more organic or
inorganic pigments and from 1 to 100% by weight, based on the
pigments, of a dispersing additive having the formula: ##STR00011##
x is 1 to 2, n is a number from 2 to 18, m and o are each a number
from 2 to 100, k is a number from 2 to 4, R'' is H or a linear or
branched alkyl radical, R' is an alkyl, alkaryl, alkenyl or
sulfopropyl radical, and with the proviso that when R= ##STR00012##
the average molecular weight of said phosphoric ester is from 500
to 5000 g/mol..Iaddend.
.Iadd.19. An aqueous paste comprising one or more organic or
inorganic colorants and from 1 to 100% by weight, based on the
colorants, of a dispersing additive having the formula:
##STR00013## x is 1 to 2, n is a number from 2 to 18, m and o are
each a number from 2 to 100, k is a number from 2 to 4, R'' is H or
a linear or branched alkyl radical, and R' is an alkyl, alkaryl,
alkenyl or sulfopropyl radical..Iaddend.
.Iadd.20. A carbon black paste comprising from 10 to 100% by
weight, based on the weight of carbon black, of a dispersing
additive having the formula: ##STR00014## x is 1 to 2, n is a
number from 2 to 18, m and o are each a number from 2 to 100, k is
a number from 2 to 4, R'' is H or a linear or branched alkyl
radical, and R' is an alkyl, alkaryl, alkenyl or sulfopropyl
radical..Iaddend.
.Iadd.21. The phosphoric ester of claim 17, wherein o is not less
than 4..Iaddend.
.Iadd.22. The aqueous paste of claim 19 wherein the ratio of m/o is
from 1:10 to 10:1..Iaddend.
.Iadd.23. The aqueous paste of claim 19 wherein the ratio of m/o is
from 1:2 to 10:1..Iaddend.
.Iadd.24. The carbon black paste of claim 20 wherein the ratio of
m/o is from 1:10 to 10:1..Iaddend.
.Iadd.25. The carbon black paste of claim 20 wherein the ratio of
m/o is from 1:2 to 10:1..Iaddend.
Description
FIELD OF THE INVENTION
The present invention relates to phosphoric esters a) obtainable by
reacting an .omega.-hydroxy-functional oligo- or poly(alkyl)styrene
with an alkylene oxide to give a
poly(alkyl)styrene-block(b)-polyalkylene oxide copolymer and then
converting said copolymer into the corresponding phosphoric esters
with a phosphorus compound which forms phosphoric esters, up to
100% of the terminal hydroxyl groups of said poly(alkyl)
styrene-block(b)-polyalkylene oxide copolymer being reacted to give
phosphoric ester groups and the phosphorus atoms, depending on the
chosen stoichiometric proportions, being mono- and/or diesterified,
or b) based on polystyrene oxide-block(b)-polyalkylene oxide
copolymers obtainable starting from a mono-functional starter
alcohol by sequential addition of styrene oxide and of an alkylene
oxide in accordance with the desired sequence and chain length of
the individual segments and subsequently by reaction to give the
corresponding phosphoric esters, in the manner described in a).
The invention relates, furthermore, to the preparation of these
phosphoric esters and to their use as dispersants for pigments and
fillers.
BACKGROUND OF THE INVENTION
For the dispersion of fillers and pigments in liquid media it is
common to operate with the aid of dispersants in order to reduce
the mechanical shear forces required for effective dispersion of
the solids and at the same time to obtain very high degrees of
filling.
The dispersants support the disruption of agglomerates, wet and/or
cover, as surface-active materials, the surface of the particles to
be dispersed, and stabilize the particles against unwanted
reagglomeration.
Dispersants have become indispensable for the preparation, for
example, of highly concentrated color pastes for the paints and
coatings industry, for the preparation of pigment concentrates
(masterbatches) for the coloring of articles made of plastic, and
for the processing of unsaturated polyester resins (UP resins)
which comprise large amounts of calcium carbonate or aluminum
hydroxide (ATH) as fillers.
The combination of very high degrees of filling in association with
a very low viscosity is of particular interest for the producers
and users of these products on primarily economic grounds. In the
case of the fillers, these commonly constitute the least expensive
formulating component; pigment concentrates are intended by the
plastics processor to be used for coloring in very highly
concentrated form--that is, as far as possible without additional
carrier materials.
Phosphoric esters and their use as dispersants are known and can be
found in the prior art. For instance, U.S. Pat. No. 4,720,514
describes phosphoric esters of a range of alkylphenol ethoxylates,
which can be used with advantage to formulate aqueous pigment
dispersions. Phosphoric esters for similar use are described in
EP-A-0,256,427, U.S. Pat. No. 5,130,463 and U.S. Pat. No. 5,151,218
report phosphoric esters based on hydroxy-terminated polyaddition
products and polycondensation products, which are used for the
preparation of highly filled polyester molding compounds,
especially for SMC and BMC formulations (SMC=sheet molding
compounds; BMC=bulk molding compounds). Bifunctional phosphoric
esters prepared by the Mannich-Moedritzer reaction, and their
adsorption characteristics on calcium carbonate, are described in
J. Appl. Polym. Sci. 65, 2545 (1997).
The known phosphoric esters, however, have the disadvantage that in
general they are not universally applicable since there is in many
cases a lack of adequate compatibility between the dispersing
additive and binder or between the dispersing additive and the
surrounding medium (aqueous or solvent-containing formulations).
The chemical composition of the phosphoric esters also has a large
part to play: in aqueous formulations it is preferred to use only
those phosphoric esters whose molecule carries no additional
hydrolyzable functional groups, such as ester or urethane groups.
Frequently, high levels of dispersing additives are required in
order to suppress the incidence of agglomerates; the degrees of
filling which can be achieved are unsatisfactorily low, the
stability of the dispersions and thus the permanence of the
viscosity is often inadequate, and flocculation and aggregation
cannot always be avoided, possibly resulting in visible separation
and in flow defects and surface defects.
BRIEF SUMMARY OF THE INVENTION
It is therefore an object of the present invention to overcome a
large number of the above disadvantages and in so doing to achieve
not only the viscosity reduction of highly filled dispersions that
is important for processability but also improved compatibility
with the surrounding medium.
This object is surprisingly achieved through the use of phosphoric
esters of amphiphilic block copolymers having the characteristic
structural feature of a poly(alkyl)styrene segment and/or a
polystyrene oxide segment to which a polyalkylene oxide segment is
attached.
The invention accordingly provides phosphoric esters of the general
formula I ##STR00002## x is 1 or 2, n is a number from 2 to 18, m
and o are each a number from 2 to 100, k is a number from 2 to 4,
R'' is H or a linear or branched alkyl radical which may if desired
be substituted by additional functional groups, and R' is an alkyl,
alkaryl, alkenyl or sulfopropyl radical.
DETAILED DESCRIPTION OF THE INVENTION
Preferably R''=H.
R' is commonly derived from an alcohol R'OH which functions as the
starter alcohol for the polymerization of the styrene oxide and
alkylene oxide.
Examples of the radicals R' are the methyl, butyl, stearyl, allyl,
hexenyl, nonylphenyl and oleyl radicals.
Methyl and butyl radicals are preferred for R'.
Where n=2 the polyether radical contains exclusively ethylene oxide
units. Where n>2, the polyether radical consists of ethylene
oxide units and, proportionally, of oxyalkylene units whose carbon
number is between 3 and 18. In this case n can adopt the value of a
fractional number between 2 and 18. Preferably, the oxyalkylene
block consists of ethylene oxide units, with the additional
presence if desired of oxybutylene units in addition to the
oxypropylene units. Oxyalkylene units having a carbon number of
from 4 to 18 are preferred when, in addition, it is desired for the
product to have oleophilic properties.
The average molecular weight of the phosphoric esters of the
invention lies within the range from 300 to about 15,000 g/mol,
preferably from 500 to 5000 g/mol. It can be determined with great
ease by the customary methods of polymer analysis, both for the
phosphoric esters and for the amphiphilic block copolymers. The
ratio of m to o is from 1:50 to 50:1, preferably from 1:10 to 10:1
and, with particular preference, from 1:2 to 10:1.
Examples of suitable phosphoric esters are: ##STR00003##
Starting materials used to prepared the phosphoric esters of the
invention are, accordingly, amphiphilic block copolymers of the
general structures: ##STR00004## respectively, where the radicals
R'' and R' and the indices m, k, n and o are as defined above.
These block copolymers are prepared by reacting the terminal
hydroxyl group with a phosphorus compound which forms phosphoric
esters, to give the phosphoric esters of the invention.
Block copolymers of this kind are described, for example, in
DE-A-41 34 967. The polystyrene-b-polyalkylene oxide copolymers of
type A-B are prepared by first subjecting styrene to free-radical
polymerization in the presence of sufficient amounts of an
initiator and of an amount, corresponding to the desired chain
length, of a chain regulator which carries not only a mercapto
group but also another functional group having an active hydrogen
radical, generally a hydroxyl group, and subjecting the resulting
polymer to an addition reaction at temperatures from 20 to
180.degree. C. with alkylene oxide until the desired molecular
weight in the block B is reached.
The corresponding polystyrene oxide-b-polyalkylene oxide copolymers
are prepared, starting from the starter alcohol R'OH, by subjecting
the corresponding alkylene oxides to a sequential addition reaction
in accordance with the desired sequence and chain length of the
individual segments so as to give a blocklike structure.
Both synthetic routes lead to a amphiphilic block copolymers having
a terminal hydroxyl group, both including, as an additional,
characteristic structural element, a hydrophobic segment composed
of aromatic groups. The processes described make it possible in a
simple manner to adapt the chain lengths m and o of the individual
segments, the overall molecular weight and the ratio m/o of
aromatic to nonaromatic segments to the technical requirements of
the particular application. For instance, products employed for
applications in aqueous systems are preferably those whose
polyalkylene oxide segment is composed of ethylene oxide units.
Conversely, products having a relatively high proportion of styrene
units and/or styrene oxide units have proven particularly suitable
for dispersion processes in a very hydrophobic environment, such
as, for example, paraffin oils, or in a polyolefin melt.
The reaction to give the phosphoric esters of the invention takes
place by reaction of the terminal hydroxyl groups with a phosphorus
compound which forms phosphoric esters, in a manner known per se.
Examples of suitable phosphorus compounds are phosphorus pentoxide,
phosphoryl chloride or polyphosphoric acids of the general formula
H.sub.n+2P.sub.nO.sub.3n+1. For the preparation of the phosphoric
esters it is particularly preferred to employ a commercially
available polyphosphoric acid (Merck) having a content of about 85%
P.sub.4O.sub.10. The reaction generally takes place without solvent
at temperatures from about 80 to 100.degree. C. To remove any
traces of moisture present it is possible first of all to remove
residues of water from the system using an inert solvent, such as
toluene or xylene, for example, prior to the reaction with the
polyphosphoric acid. Alternatively, in principle, the reaction can
be carried out in the presence of solvents or solvent mixtures.
This is always advantageous when the phosphoric esters of the
invention have to be formulated in inert solvents or solvent
mixtures in accordance with their subsequent use.
The extent of esterification of the terminal hydroxyl group of the
amphiphilic block copolymers which is the target of esterification
in the esterification reaction is preferably from 50 to 100%; with
particular preference, esterification is quantitative. Depending on
the amount of phosphorus compound which forms phosphoric esters,
employed relative to the hydroxyl equivalent of the block
copolymers, the products of the esterification are alternatively
preferably monoesters, diesters, or mixtures of monoesters and
diesters.
Depending on the pH of the medium employed, the phosphoric esters
of the invention may also be present in partially or fully
neutralized form.
The dispersants can either be applied directly to the solids that
are to be dispersed or else can be added to the aqueous and/or
organic medium. They can be distributed in pure form or as a
masterbatch in relatively high concentration in an organic medium.
It is of course also possible to employ the dispersants to be used
in accordance with the invention together with further auxiliaries
or dispersants, such as, for example, with the stearates known as
dispersants.
Appropriate solids are mineral fillers, such as talc, calcium
carbonate, dolomite, mica, wollastonite, kaolin, and mineral flame
retardants, such as aluminum hydroxide or magnesium hydroxide.
Suitable pigments are carbon black or titanium dioxide, the latter
also being employable in finely divided form as a UV protectant in
cosmetic formulations. Further dispersible solids are chemical
blowing agents, such as azodicarbonamide, or mixtures of solid
acids and carbonates.
The dispersants to be used in accordance with the invention can
also be employed for dispersing ceramic materials in organic media,
such as, for example, finely divided alumina, silicon carbide or
silicon nitride.
Suitable organic media include polyethylene, polypropylene,
polystyrene, polyamides, polyesters, poly (meth)acrylates,
polyvinyl chloride, unsaturated polyesters, and liquid
paraffins.
The dispersants of the invention are particularly suitable for
enhancing the distribution of finely divided solids in elastomers,
thermoplasts, thermosets and polymer blends.
The phosphoric esters of the invention have proven particularly
suitable as dispersants for the preparation of highly filled SMC
and BMC molding compounds. SMCs (sheet molting compounds) and BMCs
(bulk molding compounds) consist of unsaturated polyester resins, a
thermoplastic component, glass fibers, and fillers. The unsaturated
polyester resin and the thermoplastic component (polystyrene is
frequently used as the thermoplastic component) are usually
dissolved in monomeric styrene which, in the course of processing
by compression or injection molding, cures and forms a
three-dimensional network structure with the unsaturated polyester
resin. The addition of glass fibers leads to high tensile strength
and rigidity; the fillers guarantee high compressive strength and
are responsible, moreover, for good dimensional stability and low
thermal expansion.
With the phosphoric esters of the invention a very low viscosity is
achieved even at very high degrees of filling. The formulations
feature absolute freedom from inhomogeneities and a high level of
stability on storage.
In addition, the phosphoric esters of the invention can be used to
prepare aqueous pigment pastes. For this purpose, use is made of
from 0.1 to 200% by weight of the phosphoric esters, preferably
from 0.5 to 100% by weight (based on the weight of the pigments).
In the case of use in accordance with the invention the phosphoric
esters can either be mixed beforehand with the pigments to be
dispersed or else can be dissolved directly in the aqueous or
solvent-containing dispersion medium prior to or simultaneously
with the addition of pigments and any other solids.
Examples of pigments which can be mentioned in this context are
organic and inorganic pigments, including carbon blacks.
As inorganic pigments mention may be made by way of example of
titanium dioxides and iron oxides. Examples of organic pigments
which may be considered are azo pigments, metal complex pigments,
anthraquinonoid pigments, phthalocyanine pigments, polycyclic
pigments, especially those of the thioindigo, quinacridone,
dioxazine, pyrrolopyrrole, naphthalenetetracarboxylic acid,
perylene, iso-amidolin(on)e, flavanthrone, pyranthrone or
isoviolanthrone series. With particular preference, the dispersing
additives of the invention are suitable for preparing aqueous
carbon black (gas black) pastes.
Examples of fillers which can be dispersed in aqueous coating
materials are those, for example, based on kaolin, talc, other
silicates, chalk, glass fibers, glass beads, or metal powders.
Suitable coating systems in which the pigment pastes of the
invention can be incorporated are any desired aqueous 1- or
2-component coating materials. Examples which may be mentioned are
aqueous 1-component coating materials, such as those based on
alkyd, acrylate, epoxy, polyvinyl acetate, polyester or
polyurethane resins, or aqueous 2-component coating materials,
examples being those based on hydroxyl-containing polyacrylate or
polyester resins with melamine resins or, if desired, blocked
polyisocyanate resins as crosslinkers. Similarly, polyepoxy systems
may also be mentioned.
In the examples below, the preparation of the compounds to be used
in accordance with the invention is described first of all. This is
followed by performance examples demonstrating the properties of
the compounds to be used in accordance with the invention and, for
comparison, properties obtainable with some prior art products.
It is obvious and conventional to the skilled worker that these
examples represent merely a selection of the possibilities which
exist and are in no way to be regarded as a limitation.
PREPARATION EXAMPLES
1) Preparation of polystyrene-b-polyalkylene oxide copolymers (in
analogy to DE-A-41 34 967, not in accordance with the invention) as
starting materials for the preparation of the corresponding
phosphoric esters of the invention
a) Preparation of a polystyrene-b-polyalkylene oxide copolymer (in
analogy to DE-A-41 34 967)
100 g of xylene are heated to 120.degree. C. under a nitrogen
atmosphere in a reactor which is fitted with a stirrer. Over the
course of 3 hours, while maintaining the temperature of 120.degree.
C., a mixture of 1350 g (about 13 mol) of styrene, 78.1 g (1 mol)
of 2-mercaptoethanol, 4.1 g of azodiisobutyronitrile and 310 g of
xylene is added. After the end of the addition, reaction continues
for about 15 minutes; subsequently, 0.16 g of methylhydroquinone is
added.
Excess monomer, xylene and residues of 2-mercaptoethanol are
removed by distillation in vacuo and the colorless, viscous liquid
which remains is finally diluted with xylene to a solids content of
about 80%.
The molecular weight Mn determined from the hydroxyl number is 700
g/mol. The value for the molecular weight as determined by vapor
pressure osmometry is 720 g/mol.
The solution of 700 g (about 1 mol) of the
.omega.-hydroxy-functional polystyrene in 175 g of xylene and 35.0
g of potassium methylate (about 0.5 mol) are placed in a thoroughly
dried stainless steel reactor which is additionally fitted with a
stirrer. Azeotropic distillation is used to remove both traces of
water and methanol together with xylene. Subsequently, a
temperature of 80.degree. C. is established and about 2000 g of
ethylene oxide (about 45.5 mol) are added with stirring at a rate
such that the internal reactor temperature does not exceed
85.degree. C. and the pressure does not exceed 6 bar. After all of
the ethylene oxide has been introduced, the temperature is held at
80.degree. C. until a constant pressure indicates the end of the
subsequent reaction. 100 g of water are added to the resulting
product, which is then brought to a pH of from 6 to 7 with 30%
phosphoric acid. The water is removed by azeotropic distillation in
vacuo, and the salt which precipitates is removed by
filtration.
The molecular weight determined from the hydroxyl number, at an
assumed functionality of 1, is 2650; the gel permeation
chromatogram shows only one maximum and gives a value of 3100 for
Mn (calibration against PS); a value of 1.14 is obtained for the
ratio Mw/Mn.
b) Preparation of the phosphoric ester
2650 g (corresponding to 1 OH equivalent) of the block copolymer
are placed in the reactor, about 50 ml of toluene are added, and
this initial charge is heated to 120.degree. C. A vacuum is applied
to remove all of the volatile fractions, especially water which may
be present in the product, from the reaction chamber by
distillation. After blanketing with nitrogen, the temperature of
the contents is stabilized at 80.degree. C. and 85 g of liquid
polyphosphoric acid (0.25 mol P.sub.4O.sub.10; manufacturer: Merck;
purity calculated as P.sub.4O10: about 85%) are added.
After 2 hours the reaction is at an end. The acid number of the
resulting material is 41 mg of KOH/g. An aliphatic hydroxyl group
can no longer be detected in the .sup.1H-NMR spectrum.
Table 1 shows examples of some phosphoric esters based on some
polystyrene-b-polyalkylene oxide copolymers, as obtained by the
above preparation process. The table indicates the molecular
weights of the polystyrene segment and the chemical nature and
molecular weight of the corresponding alkylene oxide.
TABLE-US-00001 TABLE 1 Mn Mn Phosphoric (polystyrene (polyalkylene
Alkylene ester segment).sup.1 oxide segment).sup.1 oxide 1A 700
2000 EO.sup.2 2A 700 1000 EO 3A 1000 1000 EO 4A 1000 1000
EO/PO.sup.3 (1:1).sup.4 5A 1000 4000 EO 6A 400 1000 EO 7A 400 1800
EO .sup.1The molecular weight is calculated from the determination
of the hydroxyl number .sup.2EO = ethylene oxide .sup.3PO =
propylene oxide .sup.4Addition of a mixture of EO and PO; 1:1
denotes the molar ratio of EO to PO
2) Preparation of polystyrene oxide-b-polyalkylene oxide copolymers
(not in accordance with the invention) as starting materials in the
preparation of the corresponding phosphoric esters of the
invention
128 g (1.72 mol) of butanol and 12.2 g (0.17 mol) of potassium
methylate are placed in a reactor under a nitrogen atmosphere.
After careful flushing with ultrapure nitrogen, this initial charge
is heated to 110.degree. C. and 854 g (7.1 mol) of styrene oxide
are added over the course of one hour. After a further two hours
the addition reaction of the styrene oxide is at an end, evident
from a residual styrene oxide content of less than 0.1% (GC).
Subsequently, 2847 g (64.6 mol) of ethylene oxide are metered into
the reactor at a rate such that the internal temperature does not
exceed 120.degree. C. and the pressure does not exceed 6 bar. After
all the ethylene oxide has been introduced, the temperature is held
at 115.degree. C. until a constant manometer pressure indicates the
end of the subsequent reaction. Finally, the unreacted monomers are
removed in vacuo at from 80 to 90.degree. C.
The resulting product is neutralized using phosphoric acid and the
water is removed by distillation, and the resultant potassium
phosphate is removed by filtration together with a filtering aid.
The molecular weight determined from the hydroxyl number (Mn/OH
number), at an assumed functionality of 1, is 1950.
b) Preparation of the phosphoric ester
The preparation of the phosphoric ester takes place as described
under 1b).
Table 2 shows examples of some phosphoric esters based on
polystyrene oxide-b-polyalkylene oxide copolymers, as obtained by
the above preparation process. The table indicates the molecular
weights of the polystyrene segment and the chemical nature and
molecular weight of the corresponding alkylene oxide.
TABLE-US-00002 TABLE 2 Phosphoric Mn (polystyrene Mn (polyalkylene
Alkylene ester oxide segment).sup.1 oxide segment).sup.1 oxide 1B
450 1500 EO.sup.2 .sup. 2B.sup.3 450 1500 EO 3B 630 1100
EO/BO.sup.4 (3:1).sup.5 .sup.1The molecular weight is calculated
from the determination of the hydroxyl number .sup.2EO = ethylene
oxide .sup.3Block structure by way of 1. ethylene oxide, 2. styrene
oxide .sup.4BO = butylene oxide .sup.5Addition of a mixture of EO
and BO; 3:1 denotes the molar ratio of EO to BO
Performance Examples
The effectiveness of the dispersants to be used in accordance with
the invention is examined in accordance with various methods which
describe typical applications in the plastics or coatings
sector.
Method 1:
The fillers (or pigments) are treated with a solution of the test
dispersant in toluene. The toluene is then distilled off and the
surface-treated material is dried in vacuo. The solids coated in
this way are ground in an ultracentrifugal mill (screen size 0.5
mm) in each case to the same agglomerate size. Subsequently, the
ground solids are dispersed in liquid paraffin (30 cP) using a
mizer disk first for 2 minutes at 2000 rpm and then 3 minutes at
4000 rpm. For the experiments in accordance with Method 1 calcium
carbonate and aluminum hydroxide are coated, specifically calcium
carbonate (CaCO.sub.3) with 2% by weight of dispersant and aluminum
hydroxide (ATH) with 1% by weight of dispersant.
The viscosities are measured with a Brookfield spindle viscometer
(model LVT) at 23.degree. C. and a rotary speed of 30 rpm with
spindles of size No. 3 or No. 4. Table 3 indicates the viscosities
of the liquid paraffin dispersions filled with the corresponding
solids.
TABLE-US-00003 TABLE 3 Level of Phosphoric ester Filler filling, %
Viscosity/mPas -- ATH/CaCO.sub.3 45 n.d. 1A CaCO.sub.3 55 720 3A
CaCO.sub.3 55 410 3A ATH 65 660 6A CaCO.sub.3 55 520 Stearic acid
CaCO.sub.3 55 6900 1B CaCO.sub.3 55 560 3B CaCO.sub.3 55 820 n.d. =
not determinable: dispersion highly viscous to solid
Method 2:
The fillers are added to a defined mixture which comprises not only
the other formulating constituents but also the dispersant, using a
stirring motor with a dispersing disk (.phi.50 mm) at a speed of
rotation of about 1000 (rpm). For the performance experiments,
mixtures are chosen comprising: 60 parts of unsaturated polyester
resin (Palapreg P 17-02 or Palapreg P 14-01; manufacturer: BASF) 40
parts of thermoplastic component (Palapreg H 814-01: polystyrene,
dissolved in styrene, or Palapreg H 850-01: polymethyl
methacrylate, dissolved in styrene; manufacturer: BASF) 4.5 parts
of zinc stearate 1.5 parts of t-butyl perbenzoate 180 parts of
filler (calcium carbonate/Millicarb OG, manufacturer: Omya or
aluminum hydroxide/Martinal ON 310; manufacturer: Martinswerke) and
X parts of phosphoric esters of the invention.
In this case the viscosities are measured with a Brookfield spindle
viscometer (model DV-I) at 23.degree. C. and a rotary speed of 50
rpm with a spindle of type RVT-7. The viscosities are measured
after a storage period of 10 minutes. Tables 4 to 7 show the
viscosities of the various formulations, corresponding to the above
formulation variants. In all cases the extent of reduction in
viscosity obtainable with the dispersion of the invention is
significant.
TABLE-US-00004 TABLE 4 (UP resin: Palapreg P 17-02/thermoplastic
component: polystyrene/filler:calcium carbonate) Phosphoric ester
Amount/X parts Viscosity (mPas) -- -- 81000 2A 1.8 29000 3A 1.8
44500 5A 1.8 51500 6A 1.8 21000 7A 0.9 28500 7A 1.8 18000 7A 2.7
16000 1B 1.8 18500
TABLE-US-00005 TABLE 5 (UP resin: Palapreg P 14-01/thermoplastic
component: polystyrene/filler:calcium carbonate) Phosphoric ester
Amount/X parts Viscosity (mPas) -- -- 120000 4A 1.8 28500 7A 1.8
21000 7A 2.7 18000 1B 1.8 19500 2B 1.8 19000
TABLE-US-00006 TABLE 6 (UP resin: Palapreg P 17-02/thermoplastic
component: polystyrene/filler:ATH Phosphoric ester Amount/X parts
Viscosity (mPas/10 rpm) -- -- 240000 4A 1.8 50500 7A 1.8 33000
.sup. 7A.sup.1 5.2 255000 1B 2.7 19000 3B 1.8 21000
.sup.1Formulation contains 350 parts of ATH/5.2 parts correspond in
this way to 1.5% based on filler
TABLE-US-00007 TABLE 7 (UP resin: Palapreg P 17-02/thermoplastic
component: polymethyl methacrylate/filler:ATH) Phosphoric ester
Amount/X parts Viscosity (mPas) -- -- 54000 1A 1.8 30000 7A 1.8
27000 2B 1.8 19000
Method 3:
Preparation of pigment pastes
To prepare the pigment pastes, the dispersing additives are
dissolved beforehand 40% strength in water, mixed with water and,
if desired, with antifoams, and then the pigments are added. The
dispersion takes place following the addition of grinding media
(glass beads 2 to 3 mm, same volume as the pigment paste) for one
(titanium dioxide) or two hours (other pigments) in a Skandex
vibrator with air cooling.
Formulation of the white pastes
The white pastes are formulated as follows (amounts in % by wt.):
16.4 Water 12.3 Additive solution, 40% strength 1.0 Defoamer (e.g.,
Tego Foamex 810, Tego Chemie Service GmbH) 70.0 Titanium dioxide
2160 (Kronos) 0.3 Aerosil A 200 (fumed silica, Degussa)
Formulation of the black pastes
The black pastes are formulated as follows (amounts in % by wt.):
60.3 Water 22.3 (Dispersing) additive solution, 40% strength 1.0
Defoamer (e.g., Tego Foamex 810, Tego Chemie Service GmbH) 1.4
2-Amino-2-methylpropanol (Angus) 15.0 Pigmentary carbon black FW
200 (Dugussa)
Test coating materials
Transparent stoving enamel based on a modified alkyd resin (amounts
in % by wt): 70.88 Alkyd resin Resydrol VWA 5477, 40% strength
(Hoechst) 0.14 Defoamer (e.g. Byk 020, Byk-Chemie) 0.68 Thickener
Bentone SD 1 (Rheox) 8.24 Melamine resin Maprenal MF 900 (Hoechst)
0.14 Triethanolamine 19.10 Water 0.68 Defoamer Additol XW 395
(Hoechst) 0.14 Leveling agent Additol XW 329 (Hoechst)
Introduce item 1 and add the other components with stirring.
Transparent emulsion varnish 97.0 Acrylate dispersion Neocryl XK 90
(Zeneca) 3.0 Texanol (ester alcohol, Eastman)
To prepare paints with gray pigmentation, 40.0 g of transparent
enamel or varnish, respectively, 14.2 g of white paste and 2.65 g
of black paste are added, and the mixture is homogenized at 1500
rpm for 5 minutes. The samples are knife-coated onto aluminum
panels in a wet film thickness of 100 .mu.m and are either stoved
at 150.degree. C. for 15 minutes following a flash-off time of 20
minutes (stoving enamel) or dried at room temperature (emulsion
paint).
Test of paste stabilities
To determine the paste stabilities, the achievable initial
viscosities and the viscosities after storage at 50.degree. C. for
four weeks are determined at two different shear rates (20 l/s and
1000 l/s).
TABLE-US-00008 White pastes Viscosity/ Viscosity/ Viscosity/
Viscosity/ dPas dPas dPas dPas after 4 wk after 4 wk immediate
immediate 50.degree. C. 50.degree. C. Sample at 20 l/s at 1000 l/s
at 20 l/s at 1000 l/s 1A 3.0 0.6 3.4 0.7 2A 3.1 0.5 3.3 0.4 3A 3.3
0.7 3.5 0.7 4A 3.0 0.5 3.2 0.5 5A 3.6 0.6 3.8 0.7 6A 3.1 0.4 3.2
0.4 7A 3.3 0.5 3.4 0.6 1B 3.6 0.5 3.8 0.5 2B 3.5 0.6 3.6 0.6 3B 3.4
0.4 3.3 0.5 Polystyrene-b- 3.3 0.4 3.7 0.4 polyalkylene oxide
copolymer precursor to 1A Polystyrene-b- 3.5 0.6 3.8 0.7
polyakylene oxide copolymer precursor to 3A Fatty acid 2.8 0.5 5.5
1.0 alkoxylate Modified 4.2 1.3 6.8 1.5 acrylate polymer Black
pastes Viscosity/ Viscosity/ Viscosity/ Viscosity/ dPas dPas dPas
dPas after 4 wk after 4 wk immediate immediate 50.degree. C.
50.degree. C. Sample at 20 l/s at 1000 l/s at 20 l/s at 1000 l/s 1A
2.2 0.6 2.3 0.6 2A 2.3 0.6 2.5 0.7 3A 2.0 0.5 2.1 0.6 4A 2.4 0.7
2.4 0.7 5A 2.3 0.5 2.5 0.6 6A 1.9 0.5 2.0 0.6 7A 2.0 0.6 2.1 0.6 1B
2.3 0.7 2.4 0.7 2B 2.2 0.6 2.3 0.7 3B 2.0 0.6 2.2 0.7
Polystyrene-b- 2.0 0.6 2.2 0.7 polyalkylene oxide copolymer
precursor to 1A Polystyrene-b- 2.1 0.5 2.3 0.6 polyaklyene oxide
copolymer precursor to 3A Fatty acid 1.8 0.4 2.5 0.6 alkoxylate
Modified acrylate 3.7 0.8 4.4 1.0 polymer
The good stability of the pigment pastes of the invention is
readily evident from the rise in viscosity, which is small in each
case.
Test of dispersing properties
Application of the test formulations in a wet film thickness of 100
.mu.m; drying for 6 minutes, then rubout test over 1/3 of the
surface; after stoving or overnight drying, calorimetric
determination of the films by means of a XP 68 spectrophotometer
from X-Rite; determination of the degree of gloss and the haze by
means of Haze-Gloss from Byk-Gardner.
TABLE-US-00009 Stoving enamel based on Resydrol VWA 5477 Lightness
Delta E after Degree of gloss Sample L rubout (60.degree. angle) 1A
41.5 0.4 53 2A 42.3 0.3 51 3A 41.8 0.4 55 4A 43.2 0.4 53 5A 41.7
0.3 55 6A 40.9 0.5 54 7A 41.2 0.3 56 1B 42.2 0.3 54 2B 43.0 0.4 53
3B 42.8 0.3 53 Polystyrene-b-polyalkylene 44.0 0.6 51 oxide
copolymer precursor to 1A Polystyrene-b-polyalkylene 44.2 0.5 52
oxide copolymer precursor to 3A Fatty acid alkoxylate 44.6 0.7 49
Modified acrylate 44.9 0.4 55 polymer Emulsion paint based on
Neocryl XK 90 Delta E after Degree of gloss Sample Lightness L
rubout (60.degree. angle) Haze 1A 47.5 0.3 40.5 110 2A 47.6 0.4
42.0 115 3A 47.3 0.5 41.0 110 4A 47.9 0.3 39.0 120 5A 47.6 0.4 42.0
125 6A 47.7 0.5 41.5 115 7A 47.5 0.4 42.0 110 1B 48.0 0.4 40.5 120
2B 48.2 0.5 39.0 110 3B 48.1 0.4 42.5 125 Polystyrene-b- 48.3 0.7
39.0 120 polyalkylene oxide copolymer precursor to 1A
Polystyrene-b- 48.4 0.8 39.5 125 polyalkylene oxide copolymer
precursor to 3A Fatty acid 48.3 0.9 40.0 120 alkoxylate Modified
acrylate 49.0 0.4 40.5 130 polymer
The favorable development of color strength achievable through the
use of the dispersing additives of the invention, and the rubout
test, which is favorable in all cases, are evident.
This also becomes particularly marked in comparison with the
commercial examples not in accordance with the invention: a fatty
acid alkoxylate (Tego dispers 740W, Tego Chemie Service) and a
modified acrylate (Tego Dispers 745W).
* * * * *
References