Phosphoric esters and their use as dispersants

The invention relates to phosphoric esters of the general formula (I): ##STR1## wherein PA1 x is 1 or 2; PA1 n is a number from 2 to 18; PA1 m and n are each a number from 2 to 100; PA1 k is a number from 2 to 4; PA1 R" is H or a linear or branched alkyl radical which may be substituted by a functional radical; and PA1 R' is an alkyl, alkaryl, alkenyl or a sulfopropyl radical. The invention further relates to the use of the phosphoric esters as dispersants for pigments and fillers in aqueous or organic media and in particular to methods of forming a highly filled sheet molding compound or bulk molding compound comprising the step of dispersing components of the molding compound with said phosphoric esters.

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 monofunctional 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
 ##STR2##
 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&gt;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:
 ##STR3##
 Starting materials used to prepare the phosphoric esters of the invention
 are, accordingly, amphiphilic block copolymers of the general structures:
 ##STR4##
 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 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+2 P.sub.n O.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.4 O.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 molding 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.
 PREATION 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.4 O.sub.10 ; manufacturer:
 Merck; purity calculated as P.sub.4 O.sub.10 : 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.1 H-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 1
 Mn Mn
 Phosphoric (polystyrene (polyalkylene Alkylene
 ester segment).sup.1 oxide segment).sup.1 oxide
 1A 700 2000 .sup. EO.sup.2
 2A 700 1000 EO
 3A 1000 1000 EO
 4A 1000 1000 .sup. EO/PO.sup.3
 .sup. (1:1).sup.4
 5A 1000 4000 EO
 6A 400 1000 EO
 7A 400 1800 EO
 .sup.1 The molecular weight is calculated from the determination of the
 hydroxyl number
 .sup.2 EO = ethylene oxide
 .sup.3 PO = propylene oxide
 .sup.4 Addition 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 2
 Phosphoric Mn (polystyrene Mn (polyalkylene Alkylene
 ester oxide segment).sup.1 oxide segment).sup.1 oxide
 1B 450 1500 .sup. EO.sup.2
 .sup. 2B.sup.3 450 1500 EO
 3B 630 1100 .sup. EO/BO.sup.4
 .sup. (3:1).sup.5
 .sup.1 The molecular weight is calculated from the determination of the
 hydroxyl number
 .sup.2 EO = ethylene oxide
 .sup.3 Block structure by way of 1. ethylene oxide, 2. styrene oxide
 .sup.4 BO = butylene oxide
 .sup.5 Addition 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 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 (.O slashed.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 dispersants
 of the invention is significant.
 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 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 6
 (UP resin: Palapreg P 17-02/thermoplastic component:
 polystyrene/filler: ATH)
 Phosphoric ester Amount/X parts Viscosity (mPas/10 rpm)
 -- -- 240600
 4A 1.8 50500
 7A 1.8 33000
 .sup. 7A.sup.1 5.2 255000
 1B 2.7 19000
 3B 1.8 21000
 .sup.1 Formulation contains 350 parts of ATH/5.2 parts correspond in this
 way to 1.5% based on filler
 TABLE 6
 (UP resin: Palapreg P 17-02/thermoplastic component:
 polystyrene/filler: ATH)
 Phosphoric ester Amount/X parts Viscosity (mPas/10 rpm)
 -- -- 240600
 4A 1.8 50500
 7A 1.8 33000
 .sup. 7A.sup.1 5.2 255000
 1B 2.7 19000
 3B 1.8 21000
 .sup.1 Formulation contains 350 parts of ATH/5.2 parts correspond in this
 way to 1.5% based on filler
 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 (Degussa)
 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)
 0.014 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 1/s and 1000 1/s).