WO2007060070A1

WO2007060070A1 - Dispersants comprising solids/polyethers/polyesters

Info

Publication number: WO2007060070A1
Application number: PCT/EP2006/067692
Authority: WO
Inventors: Jürgen Meyer; Petra Lange; Andre Brötzmann; Pedro Cavaleiro
Original assignee: Evonik Degussa Gmbh
Priority date: 2005-11-23
Filing date: 2006-10-24
Publication date: 2007-05-31
Also published as: DE102005055711A1; CN1973980A

Abstract

The invention provides dispersants for solids, obtainable by full or partial reaction of A) one or more amino-functional solids with B) one or more polyesters of the general formulae (I) / (Ia) T-C (O)-[O-A-C(O)]x-OH (I) T-O-[C(O)-A-O-]y-Z (Ia) and/or C) one or more polyethers of the general formulae (II)/(IIa) T-C(O)-B-Z (II) T-O-B-Z (IIa).

Description

Dispersants comprising solids/polyethers/polyesters

The invention relates to innovative dispersants, to their preparation, and to their use for dispersing solids .

For the dispersing of solids (e.g., fillers, dyes or pigments) in liquid media it is regular practice to make use of dispersants in order to achieve effective dispersing of the solids, to reduce the mechanical shear forces required for dispersing, and at the same time to realize very high degrees of filling. The dispersants assist the disruption of agglomerates, as surface-active materials they wet and/or cover the surface of the particles to be dispersed, and stabilize said particles against unwanted reagglomeration .

In the production of paints, varnishes, printing inks, and other coating materials, dispersants facilitate the incorporation of solids, such as fillers and pigments, for example, which, as important formulating ingredients, are essential determinants of the visual appearance and of the physicochemical properties of such systems. Optimum utilization requires firstly that these solids be distributed uniformly in the formulations and secondly that the state of distribution, once attained, is stabilized.

A host of different substances are nowadays used as dispersants for solids. In addition to very simple, low molecular mass compounds, such as lecithin, fatty acids and their salts, and alkylphenol ethoxylates, more complex high molecular mass structures, too, are used as dispersants. Amino-functional and amido-functional systems in particular find broad use here.

US-A-4 224 212, EP-B-O 208 041, WO-A-00/24503, and WO-A-01/21298, for example, describe dispersants based on polyester-modified polyamines. DE-B-197 32 251 describes polyamine salts and their use as dispersants for pigments and fillers.

Use of such products, however, also entails a multiplicity of drawbacks: when they are used in pigment pastes, high levels of dispersing additives are frequently necessary; the achievable levels of pigmentation in the pastes are unsatisfactorily low; the stability of the pastes and hence their consistency of viscosity is inadequate; and flocculation and aggregation cannot always be avoided. In many instances the pastes lack consistency of hue after storage, and lack compatibility with diverse binders. The use of known dispersing additives in many cases also adversely affects the water resistance or light stability of coating materials, and additionally it further stabilizes unwanted foam produced in the course of preparation and processing. Additionally, owing to a lack of compatibility of the dispersants in numerous letdown vehicles, gloss is often affected undesirably.

There exists, consequently, a growing demand for dispersants for solids that exhibit further-improved properties as compared with the state of the art. The requirement is for dispersants which have a very high stabilizing action on a multiplicity of different solids .

With more effective dispersants, for example, it is possible to reduce the level of high-priced pigments used, without having to accept reductions in colour strength.

Moreover, the viscosity characteristics of pastes, paints, varnishes, printing inks, and other coating materials comprising dyes, solids, such as fillers and/or pigments, are critically codetermined by the dispersant used. The demand here is in particular for dispersants which result in a very low viscosity in the liquid paints and varnishes and also retain such a viscosity, preference being given to newtonian viscosity behaviour.

It was therefore an object of the present invention to provide dispersants for solids that exhibit an improved dispersing performance and have a positive influence on the viscosity and rheology of formulations comprising solids .

Surprisingly it has now been found that the aforementioned object is achieved through new dispersants for solids, obtainable by full or partial reaction of

A) one or more amino-functional solids with

B) one or more polyesters of the general formulae (I)/(Ia) T-C(O)-[O-A-C(O)J_x-OH (I)

T-O-[C(O)-A-O-]_y-Z (Ia) and/or

C) one or more polyethers of the general formulae (II)/(IIa) T-C(O)-B-Z (II)

T-O-B-Z (Ha) in which

T is a hydrogen and/or a substituted or unsubstituted, linear or branched aryl, arylalkyl, alkyl or alkenyl radical having 1 to 24 carbon atoms,

A is at least one divalent radical selected from the group of linear, branched, cyclic, and aromatic hydrocarbons, Z is at least one radical selected from the group of sulphonic acids, sulphuric acids, phosphonic acids, phosphoric acids, carboxylic acids, isocyanates, epoxides, particularly of phosphoric acid and (meth) acrylic acid, - A -

B is a radical of the general formula (III)

- (C₁H₂₁O)₃- (C_mH_2mO)_b- (C_nH_2nO)_c- (S0)_d- (III) a, b, and c independently of one another are values from 0 to 100, with the proviso that the sum of a + b + c >

0, preferably 5 to 35, in particular 10 to 20, and with the proviso that the sum of a + b + c + d > 0, d > 0, preferably 1 to 5, 1, m, and n independently of one another are > 2, preferably 2 to 4, and x and y independently of one another are > 2.

The reaction products can be in the form of the amides and/or of the corresponding salts. Where the moiety "Z" has a multiple bond, as may be the case, for example, for the polyethers and for the polyesters prepared starting from alcohol, in which the terminal OH group has been esterified with an unsaturated acid such as (meth) acrylic acid, the bond occurs via a Michael addition of the NH function across the double bond. Examples of amino-functional solids are amino- functional nanoscale powders.

The nature and the origin of the amino-functional solids present in accordance with the invention are not limited. With preference, however, it is possible to prepare amino-functional solids from solids in the form of a metal, metal oxide, metal boride, metal carbide, metal carbonate, metal nitride, metal phosphate, metal chalcogenide, metal sulphate and/or of a metal halide.

The metal may with preference be Li, Na, K, Rb, Cs, Be,

Mg, Ca, Sr, Ba, Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Co, Ni, Cu,

Zn, Ag, Cd, Hg, B, Al, Ga, In, Te, Se, Tl, Si, Ge, Sn,

Pb, P, As, Sb and/or Bi. For the purposes of the invention, the intention is also that the non-metals B, Si, and P should be included as well. In particular, the amino-functional solid may be prepared from a metal oxide containing the elements Si, Al, Ti, Fe, Ce, In, Sb, Zn, Sn, Y and/or Zr. It can be of particular advantage if the amino-functional solids are prepared from solids such as mixed metal oxides such as indium tin oxide, antimony tin oxide and mixed oxides with a matrix domain structure as for example that described in EP-A-I 284 485 or in EP-A-I 468 962.

In particular, the amino-functional solid may also comprise a metal oxide prepared by precipitation, as described for example in WO-A-00/14017.

The amino-functional surface modification of the solids to form amino-modified solids can be accomplished by spraying the oxides with the surface modifier at room temperature and then subjecting the mixture to thermal treatment at a temperature of 50 to 400⁰C over a period from 1 to 6 h.

An alternative method of surface modification of the oxides can be accomplished by treating the oxides with the surface modifier in vapour form and then subjecting the mixture to thermal treatment at a temperature of 50 to 800⁰C over a period from 0.5 to 6 h.

The thermal treatment may take place under inert gas, such as nitrogen, for example.

The surface modification may be accomplished in heatable mixers and driers with spraying installations, continuously or in batches. Suitable apparatus may for example include the following: ploughshare mixers, plate driers, fluidized bed driers or fluid bed driers.

It is possible to use all of the surface modifiers from the list below, and also mixtures of these surface modifiers. Surface modifiers used can also be amino- functional polymers from the list below.

As surface modifiers it is possible with preference to use aminopropyltriethyoxysilane, aminopropyltrimethoxy- silane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxy- silane and 3-aminopropylmethyldiethoxysilane, and with particular preference aminopropyltriethoxysilane and aminopropyltrimethoxysilane can be used as surface modifiers .

a) Organosilanes of type (RO) ₃Si (CH₂) _m-R'

R alkyl, such as methyl-, ethyl-, propyl-, m 0.1 to 20, R' -NH₂, -NH-CH₂-CH₂-NH₂,

-N- (CH₂-CH₂-CH₂) ₂,

-NH-CH₂-CH₂-NH-CH₂-CH₂-NH₂,

b) Organosilanes of type (R") _x (RO) _ySi (CH₂) _m-R' R alkyl, such as methyl-, ethyl-, propyl-, R" alkyl, cycloalkyl, x+y 3, x 1, 2, y 1, 2, R' -NH₂,

-NH-CH₂-CH₂-NH₂,

-N- (CH₂-CH₂-NH₂) ₂,

-NH-CH₂-CH₂-NH-CH₂-CH₂-NH₂,

c) Haloorganosilanes of type XsSi (CH₂ ) _m-R/ X Cl , Br, m 0 . 1 to 20 ,

R' -NH₂ ,

-NH-CH₂-CH₂-NH₂ , -N- (CH₂-CH₂-NH₂ ) ₂ ,

-NH-CH₂ -CH₂ -NH-CH₂ -CH₂ -NH₂ ,

d) Haloorganosilanes of type (R) ₂X_y Si (CH₂ ) _m-R' X Cl , Br, z + y 3 ,

Z 1 , 2 , y 1 , 2 ,

R al kyl , cycloal kyl , m 0 . 1 to 20 ,

R' -NH₂ ,

-NH-CH₂-CH₂-NH₂ ,

-N- ( CH₂-CH₂-NH₂ ) ₂ ,

-NH- CH₂ - CH₂ -NH- CH₂ - CH₂ -NH₂ .

The reaction products can be in the form of the amides and/or of the corresponding salts. Where the moiety "Z" has a multiple bond, as may be the case, for example, for the polyethers and for the polyesters, prepared starting from alcohol, in which the terminal OH group has been esterified with an unsaturated acid such as (meth) acrylic acid, the bond occurs via a Michael addition of the NH function across the double bond.

Examples of amino-functional polymers are amino- functional polyamino acids such as polylysine from Aldrich Chemical Co.; amino-functional silicones which are available under the trade name Tegomer® ASi 2122 from Degussa AG; polyamidoamines which are available under the trade names Polypox®, Aradur® or "Starburst®" dendrimers from Aldrich Chemical Co.; polyallylamines and poly (N-alkyl) allylamines which are available under the trade names PAA from Nitto Boseki; polyvinylamines which are available under the trade name Lupamin® from BASF AG; polyalkyleneimines, such as polyethylene- imines, which are available under the trade names Epomin® (Nippon Shokubai Co., Ltd.) and Lupasol® (BASF AG); and polypropyleneimines, which are available under the trade name Astramol® from DSM AG. Further examples of amino-functional polymers constitute the aforementioned systems by crosslinking with amine- reactive groups. This crosslinking reaction takes place, for example, via polyfunctional isocyanates, carboxylic acids, (meth) acrylates, and epoxides. Further examples are poly (meth) acrylate polymers which contain dimethylaminopropyl (meth) acrylamide (Degussa AG) or dimethylaminoethyl (meth) acrylate (Degussa AG) as monomers .

The skilled worker is aware that other amino-functional polymers are also possible.

Amino-functional polymers used typically are those having a molecular weight of 400 g/mol to 600 000 g/mol.

By nanoscale for the purposes of the invention are meant amino-functional solids having an average aggregate size or agglomerate size < 1000 nm and/or a primary particle size < 100 nm.

The average diameter of the nanoscale amino-functional solids in the paste of the invention is preferably < 300 nm and more preferably < 200 nm.

Examples of the radical T are alkyl radicals having 1 to 24 carbon atoms, such as the methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, hexyl, isohexyl, octyl, nonyl, isononyl, decyl, dodecyl, hexadecyl and octadecyl radical. Examples of unsubstituted or substituted aryl or arylalkyl radicals having up to 24 carbon atoms are the phenyl, benzyl, tolyl or phenethyl radical.

The polyester groups -[0-A-C(O)J_x- and - [C (O) -A-O-] _y- contain on average more than two ester groups and have an average molecular weight M_n of 100 to 5000 g/mol. Particular preference is given to a value of M_n = 200 to 2000 g/mol.

In one particularly preferred embodiment of the present invention the polyester group is obtained by conventional methods by ring-opening polymerization with a starter molecule such as T-CH₂-OH or T-COOH and one or more lactones, such as β-propiolactone, β-butyrolactone, γ-butyrolactone, 3, 6-dimethyl-l, 4- dioxane-2, 5-dione, δ-valerolactone, γ-valerolactone, ε-caprolactone, γ-caprolactone, 4-methylcaprolactone, 2-methylcaprolactone, 5-hydroxydodecanolactone,

12-hydroxydodecanolactone, 12-hydroxy- 9-octadecenoic acid, 12-hydroxyoctadecanoic acid.

Starter molecules such as T-COOH - and also the fatty alcohols T-CH₂-OH preparable therefrom - are preferably the monobasic fatty acids which are customary and known in this field and are based on natural plant or animal fats and oils having 6 to 24 carbon atoms, in particular having 12 to 18 carbon atoms, such as caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, palmitoleic acid, isostearic acid, stearic acid, oleic acid, linoleic acid, petroselinic acid, elaidic acid, arachidic acid, behenic acid, erucic acid, gadoleic acid, rapeseed oil fatty acid, soybean oil fatty acid, sunflower oil fatty acid, tall oil fatty acid, which can be used alone or in a mixture in the form of their glycerides, methyl or ethyl esters, or as free acids, and also the technical mixtures obtained in the course of pressurized cleavage. Suitable in principle are all fatty acids with a similar chain distribution.

The unsaturated content of these fatty acids or fatty acid esters is adjusted - insofar as is necessary - by means of the known catalytic hydrogenation methods to a desired iodine number or is achieved by blending fully hydrogenated with unhydrogenated fatty components.

The iodine number, as an index of the average degree of saturation of a fatty acid, is the amount of iodine absorbed by 100 g of the compound in saturating the double bonds . Not only the fatty acids but also the resultant alcohols can be modified by addition reaction with alkylene oxides, especially ethylene oxide and/or styrene oxide.

Examples of the polyether units of B are alkylene oxides such as: ethylene oxide, propylene oxide, butylene oxide, styrene oxide, dodecene oxide, tetra- decene oxide, 2, 3-dimethyloxirane, cyclopentene oxide, 1, 2-epoxypentane, 2-isopropyloxirane, glycidyl methyl ester, glycidyl isopropyl ester, epichlorohydrin, 3-methoxy-2, 2-dimethyloxirane, 8-oxabicyclo[5.1.0]- octane, 2-pentyloxirane, 2-methyl-3-phenyloxirane, 2, 3-epoxypropylbenzene, 2- (4-fluorophenyl) oxirane, tetrahydrofuran, and also their pure enantiomer pairs or enantiomer mixtures.

The group Z may be constructed from adducts of carboxylic anhydrides such as succinic anhydride, maleic anhydride or phthalic anhydride.

Further subject-matter of the invention includes the use of the dispersants of the invention for dispersing solids in liquid media, and dispersions comprising these dispersants, such as pigment pastes, coating materials, printing inks and/or print varnishes, for example .

A solid for the purposes of the present invention may in principle be any solid organic or inorganic material .

Examples of such solids are pigments, fillers, dyes, optical brighteners, ceramic materials, magnetic materials, nanodisperse solids, metals, biocides, agrochemicals, and drugs employed in the form of dispersions .

Preferred solids are pigments as specified, for example, in the Colour Index, Third Edition, Volume 3; The Society of Dyers and Colourists (1982), and in the subsequent, revised editions.

Examples of pigments are inorganic pigments, such as carbon blacks, titanium dioxides, zinc oxides, Prussian blue, iron oxides, cadmium sulphides, chromium pigments, such as chromates, molybdates, and mixed chromates and sulphates of lead, zinc, barium, calcium, and mixtures thereof. Further examples of inorganic pigments are given in the book by H. Endriss, Aktuelle anorganische Bunt-Pigmente, Vincentz Verlag, Hanover (1997) .

Examples of organic pigments are those from the group of the azo, diazo, condensed azo, Naphtol, metal complex, thioindigo, indanthrone, isoindanthrone, anthanthrone, anthraquinone, isodibenzanthrone, triphendioxazine, quinacridone, perylene, diketo- pyrrolopyrrole and phthalocyanine pigments. Further examples of organic pigments are given in the book by W. Herbst, K. Hunger, Industrial Organic Pigments, VCH, Weinheim (1993) .

Further preferred solids are fillers, such as talc, kaolin, silicas, barytes, and lime; ceramic materials, such as aluminium oxides, silicates, zirconium oxides, titanium oxides, boron nitrides, silicon nitrides, boron carbides, mixed silicon/aluminium nitrides, and metal titanates; magnetic materials, such as magnetic oxides of transition metals, such as iron oxides, cobalt-doped iron oxides, and ferrites; metals, such as iron, nickel, cobalt, and alloys thereof; and biocides, agrochemicals, and drugs, such as fungicides.

Pigment pastes, coating materials, printing inks and/or print varnishes for the purposes of the present invention may be any of a very wide variety of products . They may for example be systems comprising fillers, pigments and/or dyes. As a liquid medium they may comprise organic solvents and/or water, as is known prior art as a function of the binders used. In addition it is also possible to regard binder components as liquid media, such as polyols.

The coating materials, printing inks and/or print varnishes need not, however, necessarily contain a liquid phase, but instead may also be what are known as powder coating materials.

The coating materials, printing inks, and/or print varnishes may also comprise the typical prior-art additives, such as wetting agents, flow control agents or defoamers, etc., and may cure, crosslink and/or dry by a variety of methods in accordance with the prior art .

Examples of coating materials for the purposes of the present invention are paints, varnishes, printing inks, and other coating materials, such as solventborne and solvent-free coating materials, powder coating materials, UV-curable coating materials, low-solids, medium-solids, and high-solids automobile finishes, wood varnishes, baking varnishes, 2K [2-component ] coating materials, metal-coating materials, and toner compositions. Further examples of coating materials are given in Bodo Muller, Ulrich Poth, Lackformulierung und Lackrezeptur, Lehrbuch fur Ausbildung und Praxis, Vincentz Verlag, Hanover (2003) and in P. G. Garrat, Strahlenhartung, Vincentz Verlag, Hanover (1996).

Examples of printing inks and/or print varnishes for the purposes of the present invention are solvent-based printing inks, flexographic inks, gravure inks, letterpress or relief inks, offset inks, lithographic inks, printing inks for packaging printing, screen printing inks, inks for ink-jet printers, ink-jet ink, and print varnishes, such as overprint varnishes.

Examples of printing ink and/or print varnish formulations are given in E. W. Flick, Printing Ink and Overprint Varnish Formulations - Recent Developments, Noyes Publications, Park Ridge NJ, (1990) and subsequent editions.

The dispersants of the invention can be used in pigment pastes, coating materials, printing inks and/or print varnishes at a concentration of 0.01% to 90.0% by weight, preferably of 0.5% to 35% by weight, and more preferably of 1% to 25% by weight. If desired they can be used in a mixture with prior-art wetting agents and dispersants .

Working examples:

The invention is illustrated below with reference to working examples.

Starting materials

Amino-functional solids:

Preparation of amino-functional solids:

For surface modification, the nanoscale solids are charged to a mixer and, while being mixed intensely, are sprayed first with water, if appropriate, and subsequently with the surface modifier. When spraying is at an end, mixing may be continued for 15 to 30 min and followed by thermal conditioning at 50 to 400⁰C for 1 to 4 h.

The water used may be acidified with an acid, hydrochloric acid for example, to a pH of 7 to 1. The surface modifier used may be in solution in a solvent, such as ethanol, for example. Nanoscale solids used:

The pyrogenically prepared silicas Aerosil® 150, Aerosil® 200, and Aerosil® 250 were used from the following list:

dispersion) 4.5 4.7 4.7 4.7 4.7 4.7 4.7 4.3

SiO₂ ⁸⁾ % > 99.8 > 99.8 > 99.8 > 99.8 > 99.8 > 99.8 > 99.8 > 99.8

Al₂O₃ ⁸¹ < 0.05 < 0.05 < 0.05 < 0.05 < 0.05 < 0.05 < 0.05 < 0.08

Fe₂O₃ ^{81 ■} < 0.003 < 0.003 < 0.003 < 0.003 < 0.003 < 0.003 < 0.003 < 0.01

TiO₂ ⁸⁾ < 0.03 < 0.03 < 0.03 < 0.03 < 0.03 < 0.03 < 0.03 < 0.03

_HC18)10) < 0.025 < 0.025 < 0.025 < 0.025 < 0.025 < 0.025 < 0.025 < 0.025

Sieve residue⁶' (by

< 0.05 < 0.05 < 0.05 < 0.05 < 0.05 < 0.05 < 0.05 < 0.2 Mocker method 45 μm) %

1) in accordance with DIN 66131

2) in accordance with DIN ISO 787/XI, JIS K 5101/18 (not sieved)

3) in accordance with DIN ISO 787/11, ASTM D 280, JIS K 5101/21

4) in accordance with DIN 55921, ASTM D 1208, JIS K 5101/23

5) in accordance with DIN ISO 787/IX, ASTM D 1208, JIS K 5101/24

6) in accordance with DIN ISO 787/XVIII, JIS K 5101/20

7) based on the substance dried at 105⁰C for 2 hours

8) based on the substance calcined at 1000⁰C for 2 hours

9) special moisture barrier packaging

10) HCl content in constituent from loss on ignition

Surface modifiers:

The following surface modifiers were used:

A Aminotriethoxysilane

B Aminotrimethoxysilane

C N-2-aminoethyl-3-aminopropyltrimethoxysilane

D Lupasol® WF (BASF AG)

Preparation of surface-modified oxides:

SM* = Surface modifier: A Aminotriethoxysilane B Aminotrimethoxysilane

C N-2-aminoethyl-3-aminopropyltrimethoxysilane D Lupasol® WF (BASF AG) AF** = amino-functional solid

Physical chemical data of surface-modified oxides:

Polyesters :

Preparation of polyester 1 :

A mixture of 500 g of ε-caprolactone, 73 g of lauric acid and 0.5 g of tetrabutyl titanate was stirred under inert gas (N₂) at 150⁰C for 6 hours. This gave a waxy substance having an acid number of 36.0 mg KOH/g. The average chain length is therefore 11.7 monomeric repeating units.

In the same way as for the preparation of polyester 1, the polyesters listed in table 1 were synthesized, numbers showing the molar fractions of the compounds.

Table 1:

Polyester Structure

1 Lauric acid: ε-caprolactone (1:12)

2 Stearic acid : ε-caprolactone (1:5)

3 Capric acid: ε-caprolactone: δ-valerolactone

Preparation of acrylate-modified polyester 8:

50 g of polyester 7 and 53 g of n-butyl acrylate were introduced as an initial charge in 50 ml of toluene, and 300 ppm of hydroquinone monomethyl ether and 0.5 g of p-toluenesulphonic acid were added.

The batch was stirred with introduction of lean air until the theoretical amount of butanol produced was removed by means of a distillation column. Removal of the solvent and of the excess n-butyl acrylate gave a yellowish oil.

Polyethers:

The preparation of the polyethers below was carried out in accordance with the details in DE-C-100 29 648. The resultant modified polyethers have a general structural formula (VI)

[R-O-(SO)e(EO)_f (PO)₅(BOh]₁ P(O) (OH)₃-! (VI)

in which

R = see table 2

SO = -CH₂-CH(Ph)-O- with Ph = phenyl radical EO = ethylene oxide PO = propylene oxide BO = butylene oxide

Table 2 :

The above sequence of the monomeric alkylene oxides does not constitute any restriction on the resultant polyether structures but instead represents an exemplary listing; reference is expressly made at this point to the fact that polyethers may be constructed, using the abovementioned monomers, both randomly and blockwise. The skilled worker is aware that the modified polyether (VI) has been prepared by means of a phosphorylation reaction and that this reaction proceeds randomly. The value i represents the molar ratio of polyether to phosphate groups. The value i can vary between 0 and 2.9.

Inventive dispersants:

Example 1 :

90 g of polyester 1 and 30 g of the amino-functional solid AFl were stirred, with introduction of N₂, at 150⁰C for 6 hours. Subsequently at 50⁰C 13 g of polyether I were added with stirring. The batch continued to react at 50⁰C for 3 hours. This gave the dispersant 1, a waxy product.

Examples 2 to 18: Example 1 was repeated using the starting materials listed in table 3.

Noninventive, comparative examples:

Preparation of noninventive comparative example C 1 :

20 g of polyether I and 70 g of polyester 1 and 30 g of Aerosil 200 (non-amino-modified solid) from Degussa AG were stirred at 150⁰C for 6 hours. This gave a mixture referred to below as comparative example C 1.

Performance examples:

Test pigments:

From the multiplicity of possible solids the following commercial pigments were selected: Raven® 450 (Columbia Chemicals Co.) and Spezialschwarz® 250 (Degussa AG) as carbon black pigments, and Hostaperm® Violet P-RL (Clariant International Ltd.) and Irgalit® Yellow BAW (Ciba) as typical chromatic pigments.

Test coating materials:

The dispersants and solids were compared in the following formulas for coatings, printing inks and/or print varnishes:

Table 4 :

Formula for UV-curing flexographic ink

The ratio of amount of pigment to amount of dispersing additive was kept constant in all experiments, as a function of pigment. The dispersing additive/pigment ratio was 17.8% additive to pigment in the case of carbon black pigments and 15% additive to pigment in the case of organic chromatic pigments.

Table 5:

Formula for white, UV-curable tinting paint

Preparation :

The formula ingredients are weighed out in accordance with the above formulas into 250 ml screw top glass jars, and glass beads are added (100 g glass beads to

100 g millbase) . The sealed jars are then shaken in a

Skandex mixer (Skandex; model: BA-S20) at 620 rpm for

2 h, during which temperatures up to 50⁰C can be reached. The glass beads are subsequently separated using a sieve from the dispersed printing ink.

Tinted UV-curable flexographic ink:

For more effective assessment of the colour strengths, the UV-curable flexographic ink was blended with the white tinting paint. The blends were made in a ratio of 20:1 (41.67 g white pigment to 1 g organic chromatic pigment; and 35.71 g white pigment to 1 g carbon black pigment) . Thereafter the mixture is homogenized in a universal shaker (Hausschild Engineering, DAC 150 Dual Asymmetric Centrifuge) for 1 minute.

Application :

The tinted UV-curable flexographic inks were knife- coated onto white card (Leneta) using a spiral-wound applicator (24 μm) . Drying took place with a 120 W/cm medium-pressure mercury vapour lamp (Beltron GmbH, Beltron UV lamp) . The speed of the conveyor belt was 8 m/min.

Test methods:

In order to evaluate the performance of the dispersants, the attained colour strengths, viscosity, and rheology were plotted together.

Viscosity measurement:

The rheology of the UV-curable flexographic ink thus prepared is determined by means of a rotational viscometer. The measurement system chosen was a plate/cone system (Euro Physics, Rheo 2000 RC20, 45 μm, angle 1°; 25°C measurement temperature).

The following shear rate was chosen:

10 to 90 s^"1 in 30 s

100 to 1000 s^"1 in 40 s

The samples were compared with one another using the viscosity values measured in the outward curve at the low shear rate 10 s^"1, since it was here that the greatest differences were observed.

Colorimetry:

Colorimetry on the white blend (24 μm film thickness of Leneta card) was performed using an instrument from the company X-Rite (model: X-Rite SP 60) . For all samples the L*a*b* values of the CIE-Lab system (CIE = Commission Internationale de l'Eclairage) were determined. The CIE-Lab system is useful as a three- dimensional system for the quantitative description of colour loci. On one axis in the system the colours green (negative a* values) and red (positive a* values) are plotted, on the axis at right angles thereto the colours blue (negative b* values) and yellow (positive b* values) . The value C* is composed of a* and b* as follows: C* = (a*² + b*²)⁰'⁵ and is used to describe violet colour loci. The two axes intersect one another at the achromatic point. The vertical axis

(achromatic axis) is relevant for the lightness, from white (L = 100) to black (L = 0) . Using the CIE-Lab system it is possible to describe not only colour loci but also colour spacings, by stating the three coordinates .

Examples 19 to 37:

Dispersants 1 to 19 were tested in UV-curable flexographic ink with the carbon black pigment Spezialschwarz® 250 as described above. The results are shown in table 6 and demonstrate that the dispersants of the invention exhibited lower L* values than the comparative compounds. The desire here is for low L* values (lightness value) . The reported values in the results tables are in each case mean values from three measurements .

Table 6 :

Comparison in UV-curable flexographic ink with

Spezialschwarz® 250 pigment

Example 38:

Table 7:

Comparison in UV-curable flexographic ink with

Raven® 450 pigment

Table 8: Comparison in UV-curable flexographic ink with Spezialschwarz® 250 pigment

The desire here is for low L* (lightness values) and a low viscosity under low shearing loads. It is apparent that the dispersants used in accordance with the invention, relative to the noninventive, comparative example, exhibit lower L* values and a lower viscosity for a given shear rate.

The positive properties of the dispersant used in accordance with the invention are not only confined to black pigments but also extend to the other solids typically used in the art. The skilled worker is aware that yellow pigments and violet pigments, in particular, are difficult to disperse. Below, therefore, as examples of the universal applicability of the dispersants, the yellow pigment Irgalite® Yellow BAW (Ciba) and Hostaperm® Violet P-RL (Clariant International Ltd.) are used.

Table 9:

Comparison in UV-curable flexographic ink with

Hostaperm® Violet P-RL pigment

The desire here is for high C* values (violet values) and lower viscosity at low shearing loads. It is apparent that the dispersant used in accordance with the invention, as compared with the noninventive, comparative example, exhibits a low viscosity and a higher C* value.

Table 10 :

Comparison in UV-curable flexographic ink with

Irgalite® Yellow BAW

Irgalite® Yellow BAW b Viscosity in mPas (10 1/s; 25 ⁰C)

Blank sample 2 6. 09 3094

Comparative example C 1 3 8. 69 2925

Dispersant 1 4 8. 75 1952

The desire here is for high b* values (yellow values) and low viscosity at low shearing loads. It is apparent that the dispersant used in accordance with the invention, as compared with the noninventive, comparative example of the prior art, exhibits a lower viscosity and a higher b* value.

Claims

Claims :

1. Dispersant obtainable by full or partial reaction of

A) one or more amino-functional solids with

B) one or more polyesters of the general formulae (I)/(Ia)

T-C(O)-[O-A-C(O)J_x-OH (I) T-O-[C(O)-A-O-]_y-Z (Ia) and/or

C) one or more polyethers of the general formulae (II)/(IIa)

T-C(O)-B-Z (II) T-O-B-Z (Ha) in which

A is at least one divalent radical selected from the group of linear, branched, cyclic, and aromatic hydrocarbons,

Z is at least one radical selected from the group of sulphonic acids, sulphuric acids, phosphonic acids, phosphoric acids, carboxylic acids, isocyanates, epoxides, particularly of phosphoric acid and (meth) acrylic acid, B is a radical of the general formula (III)

- (C₁H₂₁O)₃- (C_mH_2mO)_b- (C_nH_2nO)_c- (SO) _d- (III)

a, b, and c independently of one another are values from 0 to 100, with the proviso that the sum of a + b + c > 0, preferably 5 to 35, in particular 10 to 20, with the proviso that the sum of a + b + c + d > 0, d > 0, preferably 1 to 5, 1, m, and n independently of one another are > 2, preferably 2 to 4, and x and y independently of one another are > 2.

2. Dispersant according to Claim 1, characterized in that amino-functional solids used are surface- modified nanoscale powders selected from at least one of the groups of a metal, metal oxide, metal boride, metal carbide, metal carbonate, metal nitride, metal phosphate, metal chalcogenide, metal sulphate and/or a metal halide.

3. Dispersant according to at least one of Claims 1 and 2, characterized in that the amino-functional solids have been prepared by reaction of at least some of the amino groups with one or more polyfunctional compounds selected from the group of isocyanates, carboxylic acids, (meth) acrylates, and epoxides.

4. Dispersant according to at least one of Claims 1 to 3, characterized in that the polyester groups are obtained by ring-opening polymerization of one or more lactones selected from the group of β-propiolactone, β-butyrolactone, γ-butyrolactone, 3, 6-dimethyl-l, 4-dioxane-2, 5-dione, δ-valerol- actone, γ-valerolactone, ε-caprolactone, γ-caprolactone, 4-methylcaprolactone, 2-methyl- caprolactone, 5-hydroxydodecanolactone, 12-hydrox- ydodecanolactone, 12-hydroxy-9-octadecenoic acid, 12-hydroxyoctadecanoic acid.

5. Dispersant according to at least one of Claims 1 to 4, characterized in that the polyester groups have an average molecular weight M_n of 100 to 5000 g/mol.

6. Dispersant according to at least one of Claims 1 to 5, characterized in that the polyether radicals are, independently of one another, radicals selected from the group of ethylene oxide, propylene oxide, butylene oxide, dodecene oxide, tetradecene oxide, 2, 3-dimethyloxirane, cyclo- pentene oxide, 1, 2-epoxypentane, 2-isopro- pyloxirane, glycidyl methyl ester, glycidyl isopropyl ester, epichlorohydrin, 3-methoxy-2, 2- dimethyloxirane, 8-oxabicyclo [5.1.0 ] octane, 2- pentyloxirane, 2-methyl-3-phenyloxirane, 2, 3-epoxypropylbenzene, 2- (4-fluorophenyl) oxirane, and also their pure enantiomer pairs or enantiomer mixtures .

7. Use of a dispersant according to at least one of Claims 1 to 6 as dispersants for solids for producing binder-containing or binder-free pigment pastes, coating materials, printing inks and/or print varnishes.

8. Dispersion of a solid in a liquid medium, comprising at least one dispersant according to one or more of Claims 1 to 6.