POLYMER COMPOSITION COMPRISING POLYACRYLIC BLOCK COPOLYMER AND AROMATIC BASED POLYALKYLENEOXIDE AS DISPERSANT

Field of the invention

The presently claimed invention relates to a polymer composition comprising at least one polyacrylic block copolymer and at least one aromatic based polyalkyleneoxide. The pres ently claimed invention is directed to a liquid composition in the form of a dispersion compris ing the polymer composition. The presently claimed invention is also directed to a coating composition comprising the polymer composition as a dispersant.

Background of the invention

Dispersions containing fine particulate solid materials such as pigments are widely used, e.g. as coating compositions, as printing inks, for preparing paint systems such as automotive, industrial and decorative paints, for coloring materials such as plastics and glasses and for manufacturing cosmetic compositions. An ideal dispersion consists of a homogenous and stable suspension of solid materials after size reduction or milling of any aggregates and agglomerates.

A dispersant improves various dispersion properties such as millbase viscosity and rheology behavior. The dispersant is also a determining factor of the aesthetics and physical properties of a coating. A dispersant can act as a flow control agent and bring about improved spreading of the coating composition over the surface of the substrate and improve the flow of the pol ymer film which forms in the course of curing, resulting in a smooth surface. As a conse quence, the dispersant reduces the formation of defects, known as craters, which are caused by impurities acting from the outside or by impurities on the surface of the substrate.

It is well-known that pigments such as carbon black tend to re-aggregate over a period of time, thus leading to an inhomogeneity in the coating composition, and loss in gloss or jetness properties and a detrimental increase in viscosity in the compositions.

Due to increase environmental concerns, there is a growing need for coating compositions that can be formulated using water or predominantly water as solvent and dispersants play a very important role in providing stable, water-based coating compositions.

In view of the wide application of dispersions containing fine particulate solid materials and the important role played by the dispersants in their preparation, stability and properties, there is a growing need for improved dispersants that are capable of assisting the preparation of dispersions having the desired characteristics.

The controlled free radical polymerisation (CFRP) is a tool to tailor the microstructure of pol ymers (e.g. block copolymers) in a way that is favourable for dispersing and stabilizing pigments. With the CFRP-process a large row of different polymer materials for either water borne or also solvent-borne high solids systems have become available.

However, the use of polymers obtained by CFPR process are associated with some limita tions such as high viscosity of millbase, which limits the amount of pigment concentration in millbase, crater issue in some let down systems. The usefulness of the polymer obtained by CFRP as a dispersant can be further improved to modify overall functioning and solubility in water based coatings.

Accordingly, it is an object of the presently claimed invention to provide a dispersant having improved properties such as a low millbase viscosity, and which provides a coating compo sition having improved coating properties without adversely affecting its color properties.

Summary of the invention

It was surprisingly found that a polymer composition comprising at least one polyacrylic block copolymer and at least one aromatic based polyalkyleneoxide provides a dispersant having improved dispersion properties such as a low millbase viscosity. The coating compositions comprising the polymer composition of the presently claimed invention provides surface coats having favourable properties such as a low crater ranking. Further, the dispersant composi tion does not adversely affect the color properties of the coating composition.

Accordingly, one aspect of the presently claimed invention is a polymer composition compris ing a) at least one polyacrylic block copolymer in the range from 10 to 90 wt% based on the total weight of the composition, wherein the at least one polyacrylic block copolymer is obtainable by reacting i) polymer (A) obtainable by controlled free radical polymerization of at least one acrylate monomer selected from C1-C6 alkyl esters of acrylic acid, C1-C6 alkyl esters of methacrylic acid, hydroxy C1-C6 alkyl esters of acrylic acid and hydroxy C1-C6 alkyl esters of methacrylic acid, in the presence of either a 1 or a2, wherein a1 is at least one nitroxylether of formula (I)

R ¹ R ² NOX (I), and a2 is at least one stable free nitroxyl radical of formula (II)

R ¹ R ² NO (II); wherein

R ¹ and R ² are independently selected from substituted or unsubstituted, linear or branched C5-C18 alkyl, or R ¹ and R ² together with the nitrogen atom to which they are attached form an unsubstituted or substituted 5- to 10-membered aliphatic ring comprising 1 to 3 heteroatom(s) selected from nitrogen and oxygen, and

X is selected from -CH ₂ -phenyl, -CH(CH3)-phenyl, - C(CH3)2-phenyl, -(C5-C6 cycloalkyl) ₂ C- CN, -(CH ₃ ) ₂ CCN, -CH ₂ CH=CH ₂ , -CH ₃ CH-CH=CH ₂ , -(Ci-C ₄ alkyi)CR ³ -C(0)-phenyl, -(Ci-C ₄ )al- kyl-CR ³ -C(0)-(Ci-C ₄ )alkoxy, -(Ci-C ₄ )alkyi-CR ³ -C(0)-(Ci-C ₄ )alkyl, -(Ci-C ₄ )alkyl-CR ³ -C(0)-N- di(Ci-C ₄ )alkyl, -(Ci-C ₄ )alkyi-CR ³ -C(0)-NH(Ci-C ₄ )alkyl, and -(Ci-C ₄ )alkyi-CR ³ -C(0)-NH ₂ , wherein R ³ is hydrogen or (Ci-C ₄ )alkyl; with ii) at least one ethylenically unsaturated monomer selected from a Cs-C ₂ o vinylaromatic, an ethylenically unsaturated nitrile, acrylamide, a vinyl halide, a vinyl ether of an C1-C10 alcohol and an C ₂ -Cs aliphatic hydrocarbon having one or two double bonds; and b) at least one aromatic based polyalkyleneoxide in the range from 10 to 90 wt% based on the total weight of the composition, wherein the at least one aromatic based polyalkyleneoxide is obtainable by reacting

(i) at least one monoamine functionalized polyalkyleneoxide of formula (III)

T-(0-P)n-NH ₂ (III) wherein P is a substituted or unsubstituted, linear or branched Ci-C ₄ alkylene, or a mixture of Ci-C ₄ alkylene, and

T is selected from substituted or unsubstituted, linear or branched Ci-C ₂₂ alkyl, substituted or unsubstituted Ci-C ₂₄ alkylaryl, and substituted or unsubstituted Ci-C ₂₄ dialkylaryl and n is an integer in the range of 1 to 150; with

(ii) at least one aromatic compound of the formula (IV) wherein

Q is a chemical bond or a divalent moiety selected from -0-, -NH- and -S-,

A is an unsubstituted or substituted aromatic group selected from the formula wherein # indicates the point of attachment to the rest of the molecule, and q is 0, 1 , 2, 3 or 4,

R is independently selected from halogen, N0 ₂ , OH, Ci-C ₄ -alkyl, Ci-C ₄ -alkoxy, CONH ₂ , NH-CHO, NH-Ci-C ₄ -alkyl, and NH-(C=0)-Ci-C ₄ -alkyi. Another aspect of the presently claimed invention is directed to a method for preparing the polymer composition of the present invention comprising the steps of

(i) obtaining at least one polyacrylic block copolymer and at least one aromatic based poly- alkyleneoxide as defined above, and

(ii) mixing 10 wt% to 90 wt% of the at least one polyacrylic block copolymer and 10 wt% to 90 wt% of the at least one aromatic based polyalkyleneoxide, both based on the total weight of the composition, to obtain the polymer composition.

Another aspect of the presently claimed invention is directed to a liquid composition in the form of a dispersion comprising a. a particulate solid material selected from pigments, silica and fillers, and b. a liquid diluent comprising the polymer composition according to the presently claimed invention.

Another aspect of the presently claimed invention is directed to a coating composition com prising the dispersant composition of the presently claimed invention.

Another aspect of the presently claimed invention is directed to use of the polymer composi tion of the presently claimed invention as a dispersant in a coating composition.

Detailed Description

Before the present compositions and formulations of the presently claimed invention are de scribed, it is to be understood that this invention is not limited to particular compositions and formulations described, since such compositions and formulation may, of course, vary. It is also to be understood that the terminology used herein is not intended to be limiting, since the scope of the presently claimed invention will be limited only by the appended claims.

If hereinafter a group is defined to comprise at least a certain number of embodiments, this is meant to also encompass a group which preferably consists of these embodiments only. Furthermore, the terms 'first', 'second', 'third' or 'a', 'b', 'c', etc. and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the presently claimed invention described herein are capable of operation in other sequences than described or illustrated herein. In case the terms 'first', 'second', 'third' or '(A)', '(B)' and '(C)' or '(a)', '(b)', '(c)', '(d)', 'ί', 'N' etc. relate to steps of a method or use or assay there is no time or time interval coherence between the steps, that is, the steps may be carried out sim ultaneously or there may be time intervals of seconds, minutes, hours, days, weeks, months or even years between such steps, unless otherwise indicated in the application as set forth herein above or below.

Furthermore, the ranges defined throughout the specification include the end values as well i.e. a range of 1 to 10 implies that both 1 and 10 are included in the range. For the avoidance of doubt, applicant shall be entitled to any equivalents according to applicable law.

In the following passages, different aspects of the presently claimed invention are defined in more detail. Each aspect so defined may be combined with any other aspect or aspects un less clearly indicated to the contrary. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature or features indicated as being pre ferred or advantageous.

Reference throughout this specification to 'one embodiment' or 'an embodiment' means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the presently claimed invention. Thus, appearances of the phrases 'in one embodiment' or 'in an embodiment' in various places throughout this specification are not necessarily all referring to the same embodiment but may refer to so.

Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to a person skilled in the art from this disclosure, in one or more embodiments. Furthermore, while some embodiments described herein include some, but not other features included in other embodiments, combinations of features of dif ferent embodiments are meant to be within the scope of the presently claimed invention, and form different embodiments, as would be understood by those in the art. For example, in the appended claims, any of the claimed embodiments can be used in any combination.

Accordingly, the one aspect of the presently claimed invention is a polymer composition com prising a) at least one polyacrylic block copolymer in the range from 10 to 90 wt% based on the total weight of the composition, wherein the at least one polyacrylic block copolymer is obtainable by reacting i) polymer (A) obtainable by controlled free radical polymerization of at least one acrylate monomer selected from C1-C6 alkyl esters of acrylic acid, C1-C6 alkyl esters of methacrylic acid, hydroxy C1-C6 alkyl esters of acrylic acid and hydroxy C1-C6 alkyl esters of methacrylic acid, in the presence of either a 1 or a2, wherein a1 is at least one nitroxylether of formula (I)

R ¹ R ² NOX (I), and a2 is at least one stable free nitroxyl radical of formula (II)

R ¹ R ² NO (II); wherein

R ¹ and R ² are independently selected from substituted or unsubstituted, linear or branched C5-C18 alkyl, or R ¹ and R ² together with the nitrogen atom to which they are attached form an unsubstituted or substituted 5- to 10-membered aliphatic ring comprising 1 to 3 heteroatom(s) selected from nitrogen and oxygen, and

X is selected from -Chh-phenyl, - CH(CH3)-phenyl, -C(CH3)2-phenyl, -(C5-C6 cycloalkyl)2C- CN, -(CH ₃ ) ₂ CCN, -CH ₂ CH=CH ₂ , -CH ₃ CH-CH=CH ₂ , -(Ci-C ₄ alkyl)CR ³ -C(0)-phenyl, -(Ci-C ₄ )al- kyl-CR ³ -C(0)-(Ci-C ₄ )alkoxy, -(Ci-C ₄ )alkyl-CR ³ -C(0)-(Ci-C ₄ )alkyl, -(Ci-C ₄ )alkyl-CR ³ -C(0)-N- di(CrC ₄ )alkyl, -(Ci-C ₄ )alkyl-CR ³ -C(0)-NH(Ci-C ₄ )alkyl, and -(Ci-C ₄ )alkyl-CR ³ -C(0)-NH ₂ , wherein R ³ is hydrogen or (CrC4)alkyl; with ii) at least one ethylenically unsaturated monomer selected from a C5-C20 vinylaromatic, an ethylenically unsaturated nitrile, acrylamide, a vinyl halide, a vinyl ether of an C1-C10 alcohol and an C ₂ -C ₈ aliphatic hydrocarbon having one or two double bonds; and b) at least one aromatic based polyalkyleneoxide in the range from 10 to 90 wt% based on the total weight of the composition, wherein the at least one aromatic based polyalkyleneoxide is obtainable by reacting

(i) at least one monoamine functionalized polyalkyleneoxide of formula (III)

T-(0-P)n-NH ₂ (NI) wherein P is a substituted or unsubstituted, linear or branched C ₁ -C ₄ alkylene, or a mixture of CrC ₄ alkylene, and

T is selected from substituted or unsubstituted, linear or branched C ₁ -C ₂₂ alkyl, substituted or unsubstituted C ₁ -C ₂₄ alkylaryl, and substituted or unsubstituted C ₁ -C ₂₄ dialkylaryl and n is an integer in the range of 1 to 150; with

(ii) at least one aromatic compound of the formula (IV) wherein

Q is a chemical bond or a divalent moiety selected from -O-, -NH- and -S-,

A is an unsubstituted or substituted aromatic group selected from the formula wherein # indicates the point of attachment to the rest of the molecule, and q is 0, 1 , 2, 3 or 4, R is independently selected from halogen, NO2, OH, CrC4-alkyl, CrC4-alkoxy, CONH2, NH-CHO, NH-Ci-C ₄ -alkyl, and NH-(C=0)-Ci-C ₄ -alkyl.

Within the context of the presently claimed invention, the term alkyl, as used herein, refers to an acylic saturated aliphatic groups, including linear alkyl saturated hydrocarbon radical de noted by a general formula C _n H2 _n+i and wherein n is the number of carbon atoms 1 , 2, 3, 4 etc.

Examples of linear unsubstituted Ci to C22 alkyl are methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, hep- tadecyl, octadecyl, nonadecyl, icosyl, henicosyl and docosyl.

Examples of branched unsubstituted Ci to C22 alkyl are 1 -methyl ethyl, 1 -methyl propyl, 2- methyl propyl, 1 -methyl butyl, 2-methyl butyl, 3-methyl butyl, 1 -methyl pentyl, 2-methyl pentyl,

3-methyl pentyl, 4-methyl pentyl, 1 -methyl hexyl, 2-methyl hexyl, 3-methyl hexyl, 4-methyl hexyl, 5-methyl hexyl, 1 -methyl heptyl, 2-methyl heptyl, 3-methyl heptyl, 4-methyl heptyl, 5- methyl heptyl, 6-methyl heptyl, 1 -methyl octyl, 2-methyl octyl, 3-methyl octyl, 4-methyl octyl, 5-methyl octyl, 6-methyl octyl, 7-methyl octyl, 1 -methyl nonyl, 2-methyl nonyl, 3-methyl nonyl,

4-methyl nonyl, 5-methyl nonyl, 6-methyl nonyl, 7-methyl nonyl, 8-methyl nonyl, 1 -methyl decyl, 2-methyl decyl, 3-methyl decyl, 4-methyl decyl, 5-methyl decyl, 6-methyl decyl, 7-me- thyl decyl, 8-methyl decyl, 9-methyl decyl, 1 -methyl undecyl, 2-methyl undecyl, 3-methyl un decyl, 4-methyl undecyl, 5-methyl undecyl, 6-methyl undecyl, 7-methyl undecyl, 8-methyl un decyl, 9-methyl undecyl, 10-methyl undecyl, 1 -ethyl propyl, 1 -ethyl butyl, 2-ethyl butyl, 1 -ethyl pentyl, 2-ethyl pentyl, 3-ethyl pentyl, 1 -ethyl hexyl, 2-ethyl hexyl, 3-ethyl hexyl, 4-ethyl hexyl, 1 -ethyl heptyl, 2-ethyl heptyl, 3-ethyl heptyl, 4-ethyl heptyl, 5-ethyl heptyl, 1 -ethyl octyl, 2- ethyl octyl, 3-ethyl octyl, 4-ethyl octyl, 5-ethyl octyl, 6-ethyl octyl, 1 -propyl butyl, 1 -propyl pen tyl, 2-propyl pentyl, 1 -octyl nonyl, 1 -octyl decyl, 2-octyl decyl, 1 -octyl undecyl, 2-octyl undecyl, 3-octyl undecyl, 1 -octyl dodecyl, 2-octyl dodecyl, 3-octyl dodecyl and 4-octyl dodecyl.

Within the context of the presently claimed invention, the term hydroxy-Ci-C ₆ -alkyl refers to alkyl having 1 to 6 carbon atoms (as defined above), wherein one hydrogen atom of the alkyl radical is replaced by a hydroxy group. Examples of hydroxy-Ci-C ₆ alkyl are 1 - hydroxy ethyl, 1- hydroxy propyl, 2- hydroxy propyl, 1- hydroxy butyl, 2- hydroxy butyl, 3- hydroxy butyl, 1- hydroxy pentyl, 2- hydroxy pentyl, 3- hydroxy pentyl, 4- hydroxy pentyl, 1- hydroxy hexyl, 2- hydroxy hexyl, 3- hydroxy hexyl, 4- hydroxy hexyl and 5-hydroxy hexyl.

Within the context of the presently claimed invention, the term cycloalkyl, as used herein, refers to a monocyclic and a bicyclic 3 to 10 membered saturated cycloaliphatic groups, in cluding branched cycloalkyl saturated hydrocarbon. Preferably, the cycloalkyl refers to Ci to C ₆ carbon atoms, selected from the group consisting of cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl.

Within the context of the presently claimed invention, the term alkylene refers to an acyclic saturated hydrocarbon chains, which combine different moieties. Preferably, the alkylene re fers to linear unsubstituted Ci to C4 carbon atoms, selected from the group consisting of - CH2-, -CH2-CH2-, -CH2-CH2-CH2- and -CH2-CH2-CH2-CH2-.

Within the context of the presently claimed invention, the term arylalkyl, as used herein, refers to alkyl having 5 to 24 carbon atoms (as defined above), wherein one hydrogen atom of the alkyl radical is replaced by a aryl radical.

Within the context of the presently claimed invention, the term heteroaryl, as used herein, refers to C ₅ -C ₁₀ heteroaromatic groups, for example pyrrole, pyrazole, imidazole, 2, 4, dime- thylpyrrole, 1-methylpyrrole, thiophene, furan, furfural, indole, cumarone, oxazole, thiazole, isoxazole, isothiazole, triazole, pyridine, a-picoline, pyridazine, pyrazine or pyrimidine.

Within the context of the presently claimed invention, the term alkinyl, as used herein, refers to a linear unsaturated aliphatic groups with 3 to 18 carbon atoms such as propinyl (-CH2- C=CH), 2-butinyl, 3-butinyl, n-2-octinyl, or n-2-octadecinyl.

Examples for halogen substituted alkyl are dichloropropyl, monobromobutyl or trichlorohexyl. C ₂ -C ₁₈ alkyl interrupted by at least one O atom is for example -CH ₂ -CH ₂ -O-CH ₂ -CH ₃ , -CH ₂ - CH2-O-CH3- or -CH2-CH2-O-CH2-CH2-CH2-O-CH2-CH3-. It is preferably derived from polyeth- lene glycol. A general description is -((CH ₂ ) _a -0) _b -H/CH ₃ , wherein a is a number from 1 to 6 and b is a number from 2 to 10.

In a more preferred embodiment, the polymer composition comprises a) at least one polyacrylic block copolymer in the range from 10 to 90 wt% based on the total weight of the composition, wherein the at least one polyacrylic block copolymer is obtainable by reacting i) polymer (A) obtainable by controlled free radical polymerization of at least one acrylate monomer selected from C1-C6 alkyl esters of acrylic acid, C1-C6 alkyl esters of methacrylic acid, hydroxy C1-C6 alkyl esters of acrylic acid and hydroxy C1-C6 alkyl esters of methacrylic acid, in the presence of either a 1 or a2, wherein a1 is at least one nitroxylether of formula (I)

R ¹ R ² NOX (I), wherein R ¹ and R ² are independently selected from substituted or unsubstituted, linear or branched C5-C18 alkyl, or R ¹ and R ² together with the nitrogen atom to which they are attached form an unsubstituted or substituted 5- to 10-membered aliphatic ring comprising 1 to 3 heteroatom(s) selected from nitrogen and oxygen, and

X is selected from -CH2-phenyl, - CH(CH3)-phenyl, -C(CH3)2-phenyl, -(C5-C6 cycloalkyl)2C- CN, -(CH ₃ ) ₂ CCN, -CH ₂ CH=CH ₂ , -CH ₃ CH-CH=CH ₂ , -(Ci-C ₄ alkyi)CR ³ -C(0)-phenyl, -(Ci-C ₄ )al- kyl-CR ³ -C(0)-(Ci-C ₄ )alkoxy, -(Ci-C ₄ )alkyl-CR ³ -C(0)-(Ci-C ₄ )alkyl, -(Ci-C ₄ )alkyl-CR ³ -C(0)-N- di(Ci-C ₄ )alkyl, -(Ci-C ₄ )alkyl-CR ³ -C(0)-NH(CrC ₄ )alkyl, and -(Ci-C ₄ )alkyl-CR ³ -C(0)-NH ₂ , wherein R ³ is hydrogen or (Ci-C ₄ )alkyl; with ii) at least one ethylenically unsaturated monomer selected from a C5-C20 vinylaromatic, an ethylenically unsaturated nitrile, acrylamide, a vinyl halide, a vinyl ether of an C1-C10 alcohol and an C2-C8 aliphatic hydrocarbon having one or two double bonds; and b) at least one aromatic based polyalkyleneoxide in the range from 10 to 90 wt% based on the total weight of the composition, wherein the at least one aromatic based polyalkyleneoxide is obtainable by reacting

(i) at least one monoamine functionalized polyalkyleneoxide of formula (III)

T-(0-P)n-NH ₂ (III) wherein P is a substituted or unsubstituted, linear or branched Ci-C ₄ alkylene, or a mixture of Ci-C ₄ alkylene, and

T is selected from substituted or unsubstituted, linear or branched C1-C22 alkyl, substituted or unsubstituted Ci-C2 ₄ alkylaryl, and substituted or unsubstituted Ci-C2 ₄ dialkylaryl and n is an integer in the range of 1 to 150; with

(ii) at least one aromatic compound of the formula (IV) wherein

Q is a chemical bond or a divalent moiety selected from -O-, -NH- and -S-,

A is an unsubstituted or substituted aromatic group selected from the formula and wherein # indicates the point of attachment to the rest of the molecule, and q is 0, 1 , 2, 3 or 4,

R is independently selected from halogen, NO2, OH, Ci-C ₄ -alkyl, Ci-C ₄ -alkoxy, CONH2, NH-CHO, NH-Ci-C ₄ -alkyl, and NH-(C=0)-Ci-C ₄ -alkyi. In a more preferred embodiment, the polymer composition comprises a) at least one polyacrylic block copolymer in the range from 20 to 80 wt%, and b) at least one aromatic based polyalkyleneoxide in the range from 20 to 80 wt%; both based on the total weight of the composition.

In an even more preferred embodiment, the polymer composition comprises a) at least one polyacrylic block copolymer in the range from 35 to 80 wt%, and b) at least one aromatic based polyalkyleneoxide in the range from 35 to 80 wt%, both based on the total weight of the composition.

In a most preferred embodiment, the polymer composition comprises a) at least one polyacrylic block copolymer in the range from 40 to 60 wt%, and b) at least one aromatic based polyalkyleneoxide in the range from 40 to 60 wt%, both based on the total weight of the composition.

A) Polyacrylic block copolymer

1) Acrylic acid monomer

The first polymerization step is controlled free radical polymerization (CFRP) of at least one acrylate monomer selected from C Cealkyl esters of acrylic acid, C Cealkyl esters of meth- acrylic acid, hydroxy C1-C6 alkyl esters of acrylic acid and hydroxy C1-C6 alkyl esters of meth- acrylic acid.

In a more preferred embodiment, the at least one acrylate monomer is selected from C1-C6 alkyl esters of acrylic acid.

In a most preferred embodiment, the at least one acrylate monomer is selected from n-butyl acrylate and 2-ethyl hexyl arylate.

2) Ethylenically unsaturated monomer

In the second polymerization step, the polymer obtained in the first polymerization step is reacted with at least one ethylenically unsaturated monomer selected from a C5-C20 vinylar- omatic, an ethylenically unsaturated nitrile, acrylamide, a vinyl halide, a vinyl ether of an Cr C10 alcohol and an C2-C8 aliphatic hydrocarbon having one or two double bonds.

In a preferred embodiment, the at least one ethylenically unsaturated monomer are selected from isoprene, 1 ,3-butadiene, a-Cs-Cis alkene, 4-vinyl-pyridine or pyridinium-ion, 2-vinyl-pyr- idine or pyridinium-ion, vinyl-imidazole or imidazolinium-ion, dimethylacrylamide, 3- dimethylaminopropylmethacrylamide, styrene, a-methyl styrene, p-methyl styrene, p-tert-bu- tyl-styrene and a compound of formula:

CH ₂ =C(Ra)-(C=Z)-R _b , wherein R _a is hydrogen or C ₁ -C ₄ alkyl,

R _b is NH ₂ , 0-(Me ⁺ ), unsubstituted C ₁ -C ₁₈ alkoxy, C ₂ -C ₁₀₀ alkoxy interrupted by at least one N and/or O atom, or hydroxy-substituted C ₁ -C ₁₈ alkoxy, unsubstituted C ₁ -C ₁₈ alkylamino, di(Cr C ₁₈ alkyl)amino, hydroxy-substituted C ₁ -C ₁₈ alkylamino or hydroxy-substituted di(Ci-Cie al- kyl)amino, -0-CH2-CH2-N(CH3)2 or -0-CH2-CH2-N ⁺ H(CH3)2 An-; An- is an anion of a monova- lent organic or inorganic acid; Me is a monovalent metal atom or the ammonium ion. Z is oxygen or sulfur.

In a more preferred embodiment, R _a is hydrogen or methyl, R _b is selected from NH ₂ , glycidyl, unsubstituted or with hydroxy substituted C ₁ -C ₄ alkoxy, unsubstituted C ₁ -C ₄ alkylamino, di(Cr C ₄ alkyl)amino, hydroxy- substituted C ₁ -C ₄ alkylamino and hydroxy-substituted di(C C ₄ al- kyl)amino; and Z is oxygen.

Examples for R _b as C ₂ -C ₁₀₀ alkoxy interrupted by at least one O atom are of formula, wherein R _c is C ₁ -C ₂₅ alkyl, phenyl or phenyl substituted by C ₁ -C ₁₈ alkyl, R _d is hydrogen or methyl and v is a number from 1 to 50.

These monomers are for example derived from non-ionic surfactants by acrylation of the cor responding alkoxylated alcohols or phenols. The repeating units may be derived from eth- ylene oxide, propylene oxide or mixtures of both.

Further examples of suitable acrylate or methacrylate monomers are given below. wherein An- and R _a have the meaning as defined above and R _e is methyl, benzyl or benzo- ylbenzyl. An- is preferably Cl·, Br or O3S-O-CH3.

Further acrylate monomers are

Me ⁺ is an alkali metal cation or the ammonium cation. Useful are also silicone functional (meth)acrylates.

In an even more preferred embodiment, the at least one ethylenically unsaturated monomer is selected from 3-dimethylaminopropylmethacrylamide, 2-vinyl-pyridine, 4-vinyl-pyridine, di- methylaminoethyl methacrylate, hydroxyethylacrylate, hydroxyproylacrylate, n-butylacrylate, and styrene.

In a most preferred embodiment, the at least one ethylenically unsaturated monomer is se lected from 2-vinyl-pyridine, 4-vinyl-pyridine, 3-diemthylaminopropylmathylacrylamide and di- methylaminoethyl methacrylate.

Examples for suitable ethylenically unsaturated monomer other than acrylates are

In a preferred embodiment, the ethylenically unsaturated monomer is selected from the group consisting of ethylene, propylene, n-butylene, i-butylene, styrene, substituted styrene, conju gated dienes, acrolein, vinyl acetate, vinylpyrrolidone, vinylimidazole, maleic anhydride, (al- kyl)acrylic acid- anhydrides, (alkyl)acrylic acid salts, (alkyl)acrylic esters, (alkyl)acrylonitriles, (alkyl)acryl- amides, vinyl halides and vinylidene halides. In a preferred embodiment, the ethylenically unsaturated monomer is selected from styrene, substituted styrene, methylacrylate, ethylacrylate, butylacrylate, isobutylacrylate, tert-bu- tylacrylate, hydroxyethylacrylate, hydroxypropylacrylate, dimethylaminoethylacrylate, me- thyl(meth)acrylate, ethyl-(meth)acrylate, butyl(meth)acrylate, hydroxyethyl(meth)acrylate, hy- droxypropyl(meth)acrylate, dimethylaminoethyl(meth)acrylate, acrylonitrile, methacrylonitrile, acrylamide, meth-acrylamide and dimethylaminopropyl-methacrylamide.

It is also possible to use mixtures of the aforementioned monomers, in particular styrene/ acrylonitrile, styrene/ butylacrylate, styrene/methylmethacrylate and styrene/butyl methacry late.

All possible polymer chain structures are comprised: e.g. linear or branched. If the monomers are selected from chemically different monomers, all possible monomer sequence structures are comprised, e.g. random-, blocklike, multiblock-, tapered- or gradient arrangement of the different monomers.

In a preferred embodiment, the above described controlled free radical polymerization pro cess is carried out twice to obtain a block copolymer.

In a preferred embodiment, the block copolymer is a gradient block copolymer.

Under gradient polymers or gradient arrangement there are understood block copolymers, which are prepared in such a way, that the intersection between the two blocks is not a sharp boundary, but represents a continuous transition from one type of monomer to another type of monomer, i.e. both monomers extending to both blocks. This type of polymers can be obtained when the polymerization process is carried out for example in one step using mon omers of different copolymerization parameters or by a multistep procedure, in which the monomer composition is stepwise changed by addition of appropriate amounts of another type of monomer. Another preferred procedure for the synthesis of gradient polymers is by using continuous feed processes, in which for example the controlled polymerization is started with a first monomer and before complete conversion, a second monomer is continu ously fed to the reaction mixture, thus realizing a continuous transition along the polymer chains. When controlled free radical polymerization is carried out twice and a block copolymer is obtained for example the monomer or monomer mixture of the first radical polymerization contains from 50 to 100% by weight based on total monomers of a C1-C4 alkyl or hydroxyalkyl esterofacrylic ormethacrylic acid and the second radical polymerization contains a monomer or monomer mixture possessing the ethylenically unsaturated monomer.

3) Nitroxylether of formula (I) and stable free nitroxyl radical of formula (II) In a preferred embodiment, the controlled free radical polymerization is carried out in the presence of a1.

In a preferred embodiment, the controlled free radical polymerization is carried out in the presence of a2.

Suitable nitroxylethers and nitroxyl radicals are principally known from US-A-4 581 429 or EP-A-621 878.

Particularly useful are the open chain compounds described in WO 98/13392 (Akzo), WO 99/03894 (Ciba) and WO 00/07981 (Ciba), the piperidine derivatives described in WO 99/67298 (Ciba) and GB 2335190 (Ciba) or the heterocyclic compounds described in GB 2342649 (Ciba)and WO 96/24620 (Atochem).

Further suitable nitroxylethers and nitroxyl radicals are described in WO 02/4805 (Ciba) and in WO 02/100831 (Ciba).

Nitroxylethers and nitroxyl radicals with more than one nitroxyl group in the molecule are for example described in US 6,573,347(Ciba), WO 01/02345 (Ciba) and WO 03/004471 (Ciba).

In the context of the present invention the terms alkoxyamine and nitroxylether are used as equivalents.

Stable free radicals having a structural element N-O* are for example disclosed in EP-A-621 878 (Xerox).

Examples of such as are given in WO96/24620

In a preferred embodiment, the structural element N-O-X or N-O* is part of a 5 or 6-membered heterocyclic ring, which optionally has an additional nitrogen or oxygen atom in the ring sys tem. In a more preferred embodiment, the structural element N-O-X or N-O* is part of a substituted piperidine, morpholine and piperazine derivatives.

In a preferred embodiment, the structural element N-O-X is a structural element of formula (la) wherein

Gi, G ₂ , G ₃ , G4 are independently C1-C6 alkyl or

Gi and G ₂ or G ₃ and G4, or Gi and G ₂ and G ₃ and G4 together form a Cs-Ci ₂ cycloalkyl group; G5, G ₆ independently are H, C1-C18 alkyl, phenyl, naphthyl or a group -COOC1-C18 alkyl;

X is selected from the group consisting of -CH ₂ -phenyl, CH(CH ₃ )-phenyl, C(CH ₃ ) ₂ -phenyl,

(C ₅ -C ₆ cycloalkyl) ₂ CCN, (CH ₃ ) ₂ CCN, -CH ₂ CH=CH ₂ , , CH ₃ CH- CH=CH ₂ , (C1-C4 alkyl)CR ₂ o-C(0)-phenyl, (Ci-C ₄ )alkyl-CR ₂ o-C(0)-(CrC ₄ )alkoxy, (CrC4)alkyl- CR ₂₀ -C(O)-(Ci-C ₄ )alkyl, (Ci-C ₄ )alkyl-CR ₂ o-C(0)-N-di(Ci-C ₄ )alkyl, (Ci-C ₄ )alkyl-CR ₂₀ -C(O)- NH(CrC4)alkyl, (Ci-C ₄ )alkyl-CR ₂ o-C(0)-NH ₂ , wherein R ₂ o is hydrogen or (CrC4)alkyl and ^* denotes a valence. In a preferred embodiment, the structural element N-O* is a structural element of formula (lla) wherein

Gi, G ₂ , G ₃ , G4 are independently C1-C6 alkyl or Gi and G ₂ or G ₃ and G4, or Gi and G ₂ and G ₃ and G4 together form a Cs-Ci ₂ cycloalkyl group; G5, G ₆ independently are H, C1-C18 alkyl, phenyl, naphthyl or a group -COOC1-C18 alkyl;

^* denotes a valence.

In a preferred embodiment, the structural element N-O-X is of formula A, B or O, wherein

R is hydrogen, C1-C18 alkyl which is uninterrupted or interrupted by one or more oxygen at oms, cyanoethyl, benzoyl, glycidyl, a monovalent radical of an aliphatic carboxylic acid having 2 to 18 carbon atoms, of a cycloaliphatic carboxylic acid having 7 to 15 carbon atoms, or an a,b-unsaturated carboxylic acid having 3 to 5 carbon atoms or of an aromatic carboxylic acid having 7 to 15 carbon atoms;

R ₁₀₁ is C ₁ -C ₁₂ alkyl, C ₅ -C ₇ cycloalkyl, C ₇ -C ₈ aralkyl, C ₂ -C ₁₈ alkanoyl, C ₃ -C ₅ alkenoyl or ben zoyl;

R102 is C1-C18 alkyl, C5-C7 cycloalkyl, C2-C8 alkenyl unsubstituted or substituted by a cyano, carbonyl or carbamide group, or is glycidyl, a group of the formula -CH2CH(OH)-Z or of the formula -CO-Z or -CONH-Z, wherein Z is hydrogen, methyl or phenyl;

G ₆ is hydrogen and

G5 is hydrogen or Ci-C4alkyl,

Gi and G3 are methyl and G2 and G4 are ethyl or propyl or Gi and G2 are methyl and G3 and G4 are ethyl or propyl; and

X is selected from the group consisting of -Ch -phenyl, CH(CH3)-phenyl, C(CH3)2-phenyl,

(C ₅ -C ₆ cycloalkyl) ₂ CCN, (CH ₃ ) ₂ CCN,

CH=CH2, (C1-C4 alkyl)CR ₂ o-C(0)-phenyl, (CrC ₄ )alkyl-CR ₂ o-C(0)-( CrC4)alkoxy, (CrC4)al- kyl-CR ₂₀ -C(O)-(Ci-C ₄ )alkyl, (Ci-C ₄ )alkyl-CR ₂ o-C(0)-N-di(Ci-C ₄ )alkyl, (Ci-C ₄ )alkyl-CR ₂₀ - C(0)-NH(CrC ₄ )alkyl, (Ci-C ₄ )alkyl-CR ₂ o-C(0)-NH ₂ , wherein R20 is hydrogen or (Ci-C4)alkyl.

In a preferred embodiment, the structural element N-O* is of formula A', B' or O', wherein

R is hydrogen, C1-C18 alkyl which is uninterrupted or interrupted by one or more oxygen at oms, cyanoethyl, benzoyl, glycidyl, a monovalent radical of an aliphatic carboxylic acid having 2 to 18 carbon atoms, of a cycloaliphatic carboxylic acid having 7 to 15 carbon atoms, or an a,b-unsaturated carboxylic acid having 3 to 5 carbon atoms or of an aromatic carboxylic acid having 7 to 15 carbon atoms;

R101 is C1-C12 alkyl, C5-C7 cycloalkyl, C7-C8 aralkyl, C2-C18 alkanoyl, C3-C5 alkenoyl or ben zoyl; R102 is C1-C18 alkyl, C5-C7 cycloalkyl, C2-C8 alkenyl unsubstituted or substituted by a cyano, carbonyl or carbamide group, or is glycidyl, a group of the formula -CH2CH(OH)-Z or of the formula -CO-Z or -CONH-Z, wherein Z is hydrogen, methyl or phenyl;

G ₆ is hydrogen and

G ₅ is hydrogen or C ₁ -C ₄ alkyl, Gi and G3 are methyl and G2 and G4 are ethyl or propyl or Gi and G2 are methyl and G3 and G4 are ethyl or propyl.

The above compounds and their preparation are described in GB2335190 and GB2361235.

In a preferred embodiment, the structural element N-O-Xare of formula (lc), (Id), (le), (If), (Ig) or (Ih) wherein

R201 , R202, R203 and R204 independently of each other are C1-C18 alkyl, C3-C18 alkenyl, C3-C18 alkinyl, C1-C18 alkyl , C3-C18 alkenyl, C3-C18 alkinyl, which are substituted by OH, halogen or a group -O-C(O)-R205, C2-C18 alkyl which is interrupted by at least one O atom and/or N R205 group, C3-C12 cycloalkyl or C ₆ -Cioaryl or R201 and R202 and/or R203 and R204 together with the linking carbon atom form a C3-C12 cycloalkyl radical;

R ₂₀₅ , R ₂₀₆ and R ₂₀₇ independently are hydrogen, C ₁ -C ₁₈ alkyl or C ₆ -C ₁₀ aryl;

R208 is hydrogen, OH, C1-C18 alkyl, C3-C18 alkenyl, C3-C18 alkinyl, C1-C18 alkyl, C3-C18 alkenyl, C3-C18 alkinyl, which are substituted by one or more OH, halogen or a group -O-C(O)-R205, C ₂ -

C10 alkyl which is interrupted by at least one O atom and/or N R205 group, C3-C12 cycloalkyl or C6-C10 aryl, C7-C9 phenylalkyl, C5-C10 heteroaryl, -C(0)-Ci-Ci8 alkyl, -O-C1-C18 alkyl or - COOC1 -C18 alkyl;

R ₂₀₉ , R ₂₁₀ , R ₂₁₁ and R ₂₁₂ are independently hydrogen, phenyl or C ₁ -C ₁₈ alkyl; and

X is selected from the group consisting of -CH2-phenyl, CH(CH3)-phenyl, C(CH3)2-phenyl,

(C ₅ - C ₆ cycloalkyl) ₂ , -CH ₂ CH=CH ₂ , CH ₃ CH-

CH=CH ₂ , (CrC ₄ alkyl)CR ₂ o-C(0)-phenyl, (Ci-C ₄ )alkyl-CR ₂ o-C(0)-(CrC ₄ )alkoxy, (CrC4)alkyl- CR ₂₀ -C(O)-(Ci-C ₄ )alkyl, (Ci-C ₄ )alkyl-CR ₂ o-C(0)-N-di(Ci-C ₄ )alkyl, (Ci-C ₄ )alkyl-CR ₂₀ -C(O)- NH(CrC4)alkyl, (Ci-C ₄ )alkyl-CR ₂ o-C(0)-NH ₂ , wherein R ₂ o is hydrogen or (Ci-C4)alkyl.

More preferably in formula (lc), (Id), (le), (If), (Ig) and (Ih) at least two of R ₂ OI , R ₂ o2, R203 and R ₂ 04 are ethyl, propyl or butyl and the remaining are methyl; or

R _2OI and R ₂ o2 or R ₂ o ₃ and R ₂ 04 together with the linking carbon atom form a C5-C6 cycloalkyl radical and one of the remaining substituents is ethyl, propyl or butyl.

Most preferably X is CH(CH ₃ )-phenyl.

The above compounds and their preparation are described in GB 2342649.

In a preferred embodiment, the structural elements N-O-X and N-O* are 4-imino compounds of formula wherein

G11 , G _I2 , G _I3 and G14 are independently C1-C4 alkyl or

G11 and G _I2 together and G _I3 and G14 together, or Gn and G _I2 together or G _I3 and G14 to gether are pentamethylene;

Gi5 and G16 are each independently of the other hydrogen or C1-C4 alkyl;

X is as defined above; k is 1 , 2, 3, or 4

Y is O or NR _3O 2 or when k is 1 and R _3OI represents alkyl or aryl Y is additionally a direct bond; R _3O 2 is H, C1-C18 alkyl or phenyl; if k is 1

R ₃ OI is H, straight or branched C1-C18 alkyl, C ₃ -Cis alkenyl or C ₃ -Cis alkinyl, which may be unsubstituted or substituted, by one or more OH, C Cs alkoxy, carboxy, C Cs alkoxycar- bonyl; cycloalkyl or Cs-Ci ₂ cycloalkenyl; phenyl, C7-C9 phenylalkyl or naphthyl which may be unsubstituted or substituted by one or more C Cs alkyl, halogen, OH, C Cs alkoxy, carboxy, C Cs alkoxycarbonyl; -C(0)-CrC ₃₆ alkyl, or an acyl moiety of a a,b-unsaturated carboxylic acid having 3 to 5 carbon atoms or of an aromatic carboxylic acid having 7 to 15 carbon atoms;

-SOsCr, -P0(0-Q ⁺ ) ₂ , -P(0)(0Ci-C ₈ alkyl ₂ )2, -P(0)(0H ₂ ) ₂ , -S0 ₂ -OH, -S0 ₂ -Ci-C ₈ alkyl, -CO- NH- Ci-C ₈ alkyl, -CONH ₂ , COO- Ci-C ₈ alkyl ₂ , COOH or Si(Me)3, wherein Q ⁺ is H ⁺ , ammonium or an alkali metal cation; if k is 2

R301 is Ci-Cis alkylene, C3-Ci ₈ alkenylene or C3-Ci ₈ alkinylene, which may be unsubstituted or substituted, by one or more OH, Ci-C ₈ alkoxy, carboxy, Ci-C ₈ alkoxycarbonyl; or xylylene; or R301 is a bisacyl radical of an aliphatic dicarboxylic acid having 2 to 36 carbon atoms, or a cycloaliphatic or aromatic dicarboxylic acid having 8-14 carbon atoms; if k is 3,

R301 is a trivalent radical of an aliphatic, cycloaliphatic or aromatic tricarboxylic acid; and if k is 4,

R ₃₀₁ is a tetravalent radical of an aliphatic, cycloaliphatic or aromatic tetracarboxylic acid.

Preferably G16 is hydrogen and G15 is hydrogen or C1-C4 alkyl, in particular methyl, and Gn and Gi3 are methyl and GI ₂ and G14 are ethyl or propyl or Gn and GI ₂ are methyl and G13 and Gn are ethyl or propyl.

The 4 imino compounds of formula (III) or (IV) can be prepared for example according to E.G. Rozantsev, A.V. Chudinov, V.D. Sholle. : Izv. Akad. Nauk. SSSR, Ser. Khim. (9), 2114 (1980), starting from the corresponding 4-oxonitroxide in a condensation reaction with hydroxylamine and subsequent reaction of the OH group. The compounds are described WO 02/100831 (Ciba).

In a preferred embodiment, the controlled free radical polymerization process is carried out in the presence of a1). The nitroxylether of formula (I) according to the structures outlined above splits between the O-X bond. The regulating fragment in formula (I) corresponds to the O-N fragment and the initiating fragment (In) corresponds to the C centred radical of the group X.

In a more preferred embodiment, suitable nitroxylethers and nitroxyl radicals are those of formulae:

In a particularly preferred embodiment, the at least one nitroxylether is a compound of formula 5 (la). In a preferred embodiment, the initiator compound (a1 or a2) is present in an amount of from 0.01 mol-% to 30 mol-%, more preferably in an amount of from 0.1 mol-% to 20 mol-% and most preferred in an amount of from 0.1 mol-% to 10 mol-% based on the amount of the monomer or monomer mixture.

When monomer mixtures are used, mol% is calculated on the average molecular weight of the mixture.

When the controlled free radical polymerization is carried out in the presence of a2, the free radical initiator is preferably an azo compound, a peroxide, perester or a hydroperoxide.

In a more preferred embodiment, the free radical initiator are 2,2'-azobisisobutyronitrile, 2,2'- azobis(2-methyl-butyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(4-methoxy- 2,4-dimethylvaleronitrile), 1 ,1'-azobis(1-cyclohexanecarbonitrile), 2,2'-azobis(isobutyramide) dihydrate, 2-phenylazo-2,4-dimethyl-4-methoxyvaleronitrile, dimethyl-2, 2'-azobisisobutyrate, 2-(carbamoylazo)isobutyronitrile, 2,2'-azobis(2,4,4-trimethylpentane), 2,2'-azobis(2- methylpropane), 2,2'-azobis(N,N'-dimethyleneisobutyramidine), free base or hydrochloride, 2,2'-azobis(2- amidinopropane), free base or hydrochloride, 2,2'-azobis{2-methyl-N-[1 ,1- bis(hydroxy-methyl)ethyl]propionamide} or 2,2'-azobis{2-methyl-N-[1 ,1-bis(hydroxymethyl)- 2-hydroxy- ethyl]propionamide; acetyl cyclohexane sulphonyl peroxide, diisopropyl peroxy dicarbonate, t-amyl perneodecanoate, t-butyl perneodecanoate, t-butyl perpivalate, t-am- ylperpivalate, bis(2,4-dichlorobenzoyl)peroxide, diisononanoyl peroxide, didecanoyl perox ide, dioctanoyl peroxide, dilauroyl peroxide, bis(2-methylbenzoyl) peroxide, disuccinic acid peroxide, diacetyl peroxide, dibenzoyl peroxide, t-butyl per 2-ethylhexanoate, bis-(4-chloro- benzoyl)-peroxide, t-butyl perisobutyrate, t-butyl permaleinate, 1 ,1-bis(t-butylperoxy)3, 5,5- trimethyl-cyclohexane, 1 ,1-bis(t-butylperoxy)cyclohexane, t-butyl peroxy isopropyl car bonate, t-butyl perisononaoate, 2,5-dimethylhexane 2,5-dibenzoate, t-butyl peracetate, t- amyl perbenzoate, t-butyl perbenzoate, 2,2-bis(t-butylperoxy) butane, 2,2 bis(t-bu- tylperoxy)propane, dicumyl peroxide, 2,5-dimethylhexane-2,5-di-t-butylperoxide, 3-t-butyl peroxy 3-phenylphthalide, di-t-amyl peroxide, a,a'-bis(t-butylperoxyisopropyl)benzene, 3,5- bis(t-butylperoxy)3,5-dimethyl-1 ,2-dioxolane, di-t-butyl peroxide, 2,5-dimethylhexyne-2,5-di- t-butylperoxide, 3,3,6,6,9,9-hexamethyl 1 ,2,4,5-tetraoxacyclononane, p-menthane hydroper oxide, pinane hydroperoxide, di isopropyl benzene mono-a-hydroperoxide, cumene hydroper oxide or t-butyl hydroperoxide.

In a preferred embodiment, the free radical initiator is present in an amount of from 0.01 mol- % to 30 mol-%, more preferably in an amount of from 0.1 mol-% to 20 mol-% and most pref erably in an amount of from 0.5 mol-% to 10 mol-% based on the amount of the monomer or monomer mixture.

In a preferred embodiment, the molar ratio of the free radical initiator to the nitroxyl radical is in the range from 1 :10 to 10:1 , more preferably from 1 :5 to 5:1 , and most preferably from 1 :2 to 2:1.

In a preferred embodiment, the polymer or copolymer prepared according by the controlled free radical polymerization has a molecular weight (M _w ) in the range from 2,000 g/mol to 50,000 g/mol, more preferably from 5,000 g/mol to 30,000 g/mol, and most preferably from 8,000 g/mol to 20,000 g/mol.

In a preferred embodiment, the polymer or copolymer prepared according by the controlled free radical polymerization has a polydispersity index of 1.0 to 2.2, more preferably from 1.1 to 1.9, and most preferably from 1.1 to 1.5.

T ransesterification

The polyacrylic block copolymer is optionally subjected to functionalization by transesterifica tion with at least one alcohol. In transesterification, the alcohol radical in an ester group of the polymer or copolymer is replaced by another alcohol radical.

In a preferred embodiment, the at least one polyacrylic block copolymer is subjected to func tionalization with at least one alcohol selected from W1 and W2, wherein,

W1 is R ⁴ -OH, wherein R ⁴ is a substituted or unsubstituted, linear or branched C8-C36 alkyl;

W2 is at least one polyether alcohol of formula G-(0-Q) _n -OH wherein G is a substituted or unsubstituted, linear or branched C1-C4 alkylene, and Q is selected from substituted or unsubstituted, linear or branched C1-C22 alkyl, substituted or unsubstituted C1-C24 alkylaryl, and substituted or unsubstituted C1-C24 dialkylaryl, and n is an integer in the range of 1 to 150.

Typically, the transesterification reaction is carried out at elevated temperatures, typically 70 - 200°C, by reacting the polymer obtained from CFRP with the corresponding alcohol in the presence of well-known catalysts, such as tetra-isopropyltitanate, tetra-butyltitanate, alkali- or earth alkali alcoholates like NaOMe or LiOMe. Typically, the low boiling product alcohol is removed from the transterification reaction mixture by distillation. If required, catalyst residues may be removed by adsorption or extraction or otherwise processed or inactivated by known methods, like hydrolysis with water or acids.

The choice of the replacing alcohol is important as the replacing alcohol controls the proper ties of the resulting copolymer.

By using a polar replacing alcohol such as alcohols having e.g. the following formula R-[0- CH ₂ -CH ₂ -] _n -OH, e.g. methoxypolyethylene glycol (MPEG-OH), a water-soluble resulting pol ymer can be obtained. The solubility depends on the amount of transesterified monomer units. At least 40 % of the units should be transesterified to obtain the desired effect.

If the solubility in organic solvents is required, nonpolar alcohols like higher molecular weight branched aliphatic alcohols can be beneficial.

If polymers with low surface tension are desired, alcohols containing siloxane groups are preferred, e.g. with the following formula or partly or fully fluorinated primary alcohols can be used instead or in addition.

If a solid copolymer is required, solid alcohols or polar alcohols which are able to raise the glass transition temperature (T _g ) or impart side chain crystallinity should be used. An example is behenyl alcohol.

The replacing alcohol radical is typically an aliphatic C6-C36 alcohol or a precursor of an alco hol, having at least one -OH group. The alcohol may also be interrupted by 1 to 20 O or N atoms or substituted by halogen, perfluoralkyl, NH2, NH(C _I -C _I8 alkyl), N(C _I -C _I8 alkyl)2, COO(Ci-Ci8 alkyl), CON(CI-CI ₈ alkyl) ₂ , CONH(CI-CI ₈ alkyl), CONH ₂ , COOH, COO-, 0(Cr Ci ₈ alkyl) or with a Si, P or S containing group, for example alkylhydroxysilicones. The alcohol may also contain heterocyclic ring structures, such as 1-(2-hydroxyethyl)-2-pyrrolidinone, 1- (2-hydroxyethyl)-2-imidazolidinone, 2-(2-hydroxyethyl)pyridine, N-2-hydroxyethyl)phtalimide, 4-(2-hydroxyethyl)morpholine, 1-(2-hydroxyethyl)piperazine, N-hydroxymethylphthalimide, 3- hydroxymethylpyridine or (4-pyridyl)-1 -propanol.

The alcohols, which are interrupted by O or N atoms are not limited to 36 C atoms. These can be oligomeric or polymeric alcohols also. Examples of alcohols interrupted by O atoms are methoxypolyethyleneglycols or adducts of ethyleneoxide and/or propylene- oxide (EO/PO). Such EO/PO-adducts can be random or block type structures.

In a more preferred embodiment, the alcohol is an unsubstituted linear or branched C8-C36 alkyl monoalcohol or a monoalcohol derived from ethylenoxide, propylenoxide or mixtures thereof with up to 100 C atoms.

In an even more preferred embodiment, the alcohol is methoxypolyethyleneglycol (MPEG- OH).

In an embodiment, the at least one polyether alcohol is methoxypolyethyleneglycol with the molecular weight (M _w ) of 200-1000 g/mol.

It is also possible to use fatty acid alcohol ethoxylates, alkylphenolethoxylates, alkoxylates of all kinds of monofuntional alcohols or phenols or secondary amines. Preferably the alkoxylate is an ethoxylate of a primary alcohol or alkylphenol of structure (A):

R-[0-CH ₂ -CH ₂ -]n-0H (A) wherein R is saturated or unsaturated, linear or branched chain alkyl with 1 -22 carbon atoms, or alkylaryl or dialkylaryl with up to 24 carbon atoms and n is 1 to 50.

Referring to another embodiment the alcohol is an unsubstituted linear or branched C8-C36 alkyl mono alcohol or mixtures thereof. An example is a mixture of iso Ci ₂ -Ci5 alcohol. Non polar polymers or copolymers are obtained.

In another embodiment, the macroalcohol is a primary OH-functional silicone oligomer. Pre ferred are polydimethylsilicone oligomers of structure (B): wherein

R is C ₁ -C ₁ 8 alkyl, phenyl or C ₇ -C ₁₅ aralkyl; n is 1 to 50; and R' is a linking group with 1 to 20 carbon atoms. Typical linking groups are C ₁ -C ₁ 8 alkylene, phenylene or C ₁ -C ₁ 8 alkylene inter rupted by 1 to 6 oxygen atoms. In another embodiment the alcohol is a partly or fully fluorinated primary alcohols. Examples of commercial fluorinated alcohol mixtures are: Zonyl BA®, Zonyl BA-L®, Zonyl BA-LD®, Zonyl BA-N® from Du Pont.

Precursors of alcohols are for example macroalcohols, such as poly-s-caprolactone oligo mers or e-caprolactone adducts and similar lactone adducts (e.g. based on valerolactone) or mixed adducts of e-caprolactone and valerolactone. Typical lactone adducts are adducts of e-caprolactone to long chain fatty alcohols of structure: R-[0-C0-CH ₂ -CH ₂ -CH ₂ -CH ₂ -CH ₂ -] _n -0H wherein R is saturated or unsaturated, linear or branched chain alkyl with 8 -22 carbon atoms or alkylaryl or dialkylaryl with up to 24 carbon atoms and n is 1 to 50. It is also possible to use macroalcohols based on polyolefins, which have typically molecular weights (M _w ) up to 5000, preferably up to 2000.

Yet another embodiment are unsaturated alcohols containing carbon-carbon double bonds or carbon triple bonds. An example is oleyl alcohol. Regarding triple bond preferred are pri mary alkinols like propargyl alcohol and higher homologues like alkylsubstituted propargylal- cohol.

Preferably the alcohol is a monoalcohol and is a primary or secondary alcohol. Most preferred are primary alcohols or alcohol mixtures like Lial 125.

Preferably the alcohol or alcohol mixture is non-volatile and has a boiling point or range of at least 100°C, more preferably of at least 200°C.

B) Aromatic based polyalkyleneoxide

The aromatic based polyalkyleneoxide bear at least one, e.g. on an average 1 to 250, in particular 2 to 150 and especially 5 to 100 aromatic moieties P.1 per polymer molecule. In this context, the term "on average" is understood as the number average. Each of the moie ties P.1 is bound to a nitrogen atom of the polyalkylene imine backbone via a carboxamide or carboximide group.

The aromatic moiety P.1 comprises either an optionally substituted aryl, which is bound to a nitrogen atom of the polyethylene imine radical via a carbonyl group, thereby forming a car boxamide group, or an optionally substituted arylene radical which is bound to a nitrogen atom of the polyethylene imine radical via two carbonyl groups, thereby forming a car boximide group. The aryl or arylene moieties of P.1 are unsubstituted or substituted, e.g. by 1 , 2, 3, 4 or 5 radicals, which are preferably selected from halogen, OH, CrC4-alkyl, C1-C4- alkoxy, COOH, CONH ₂ , NH ₂ , N0 ₂ , NH-CHO, NH-Ci-C ₄ -alkyl, and NH-(C=0)-Ci-C ₄ -alkyl. Within the aromatic based polyalkyleneoxide, the radicals P.1 may be identical or different. Preferably, they are identical.

The moieties P.1 will generally contribute by an amount of 1 to 25% by weight, in particular from 1.5 to 15% by weight or from 2 to 10% by weight to the total weight of the polymer. The relative amount of the moieties P.1 to the polyalkylene imine may be from 10 to 200% by weight, in particular from 20 to 150% by weight.

In a preferred embodiment, the moiety P.1 is selected from the moieties of the formula (P.T) and (P.1")

(P.T) (P.1") where

# indicates the point of attachment to a nitrogen atom of the polyalkylene imine backbone, Ar is phenyl or naphthyl, wherein phenyl and naphthyl, each independently are unsubsti tuted or carry 1, 2, 3, 4 or 5 radicals R, which are selected from halogen, OH, Ci-C4-alkyl, Cr C ₄ -alkoxy, COOH, CONH ₂ , NH ₂ , N0 ₂ , NH-CHO, NH-Ci-C ₄ -alkyl, and NH-(C=0)-Ci-C ₄ -alkyi, Ar' is 1 ,2-phenylene, 1 ,2-, 2,3-, or 1 ,8-naphthylene, wherein phenylene and naphthylene, each independently are unsubstituted or carry 1 , 2, 3, 4 or 5 radicals R, which are selected from halogen, OH, Ci-C ₄ -alkyl, Ci-C ₄ -alkoxy, COOH, CONH ₂ , N0 ₂ , NH ₂ , NH-CHO, NH-Ci- C ₄ -alkyl, and NH-(C=0)-Ci-C ₄ -alkyi.

In this context, Ar and Ar' preferably have the following meanings:

Ar is phenyl or 1 -naphthyl, wherein phenyl and naphthyl, each independently are unsub stituted or carry 1 , 2 or 3 radicals R, in particular 1 or 2 radicals R, where R are identical or different and independently of each other are selected from halogen, OH, Ci-C ₄ -alkyl, Ci-C ₄ - alkoxy, COOH, CONH ₂ , NH ₂ , N0 ₂ , NH-CHO, NH-Ci-C ₄ -alkyl, and NH-(C=0)-Ci-C ₄ -alkyi,

Ar' is 1 ,2-phenylene or 1 ,8-naphthylene, wherein phenylene and naphthylene each inde pendently are unsubstituted or carry 1 , 2 or 3 radicals R, in particular 1 radical R, where R are identical or different and independently of each other are selected from halogen, OH, Cr C ₄ -alkyl, Ci-C ₄ -alkoxy, COOH, CONH ₂ , NH ₂ , N0 ₂ , NH-CHO, NH-Ci-C ₄ -alkyl, and NH-(C=0)- Ci-C ₄ -alkyl.

In the context of formulae P.T, P.1", the substituents R on phenylene or naphthylene, if pre sent, are in particular selected from the group consisting of Cl, NH ₂ , N0 ₂ , COOH, NH-CHO, NH-CHs, and NH-(C=0)-CH ₃ . In particular, the moiety P.1 is selected from the group consisting of radicals of the formulae (P.1a), (P.1b), (P.1c), (P.1d), and (P.1e), wherein

# indicates the point of attachment to a nitrogen atom of the polyalkylene imine backbone, q is 0, 1 , 2, 3 or 4, in particular 0 or 1 ,

R' is hydrogen, CrC4-alkyl, -CHO, or -(C=0)-Ci-C ₄ -alkyl, in particular hydrogen, methyl CHO or -(C=0)-CH ₃ and especially methyl;

R is independently or identical selected from the group consisting of halogen, OH, NO2, Ci-C ₄ -alkyl, Ci-C ₄ -alkoxy, CONH ₂ , NH-CHO, NH-Ci-C ₄ -alkyl, and NH-(C=0)-Ci-C ₄ -alkyl.

In the context of formulae P.1a, P.1b, P.1c, P.1d and P.1e, the radical R, if present, is in particular selected from the group consisting of Cl, NH2, NO2, NH-CHO, NH-CH3, and NH- (C=0)-CH ₃ .

Examples of moieties P.1 include 2-aminophenylcarbonyl (P.1 a with q = 0), 2,5-diamino- phenylcarbonyl (P.1a with q = 1 , R = 5-NH2), 2-amino-5-bromophenylcarbonyl (P.1a with q = 1 , R = 5-Br), 2-carboxyphenylcarbonyl (P.1b with q = 0), 2,4-dicarboxyphenylcarbonyl (P.1b with q = 1 , R = 4-COOH), 8-carboxynaphthyl-1 -carbonyl (P.1c with q = 0), 3-bromo-8- carboxynaphthyl-1 -carbonyl (P.1c with q = 1 , R = 3-bromo), 6-bromo-8-carboxynaphthyl-1- carbonyl (P.1c with q = 1 , R = 6-bromo), 3-nitro-8-carboxynaphthyl-1-carbonyl (P.1c with q = 1 , R = 3-NO2), 4-nitro-8-carboxynaphthyl-1 -carbonyl (P.1c with q = 1 , R = 4-NO2), 5-nitro- 8-carboxynaphthyl-1 -carbonyl (P.1c with q = 1 , R = 5-NO2), 6-nitro-8-carboxynaphthyl-1- carbonyl (P.1c with q = 1 , R = 6-NO2), 1 ,2-phenylendicarbonyl (radical P.1d with q = 0), 4- carboxy-1 ,2-phenylendicarbonyl (radical P.1d with q = 1 , R = 4-COOH), 1 ,8-nahpthy- lendicarbonyl (radical P.1e with q = 0), 3-bromo-1 ,8-nahpthylendicarbonyl (radical P.1e with q = 1 , R = 3-Br), 3-nitro-1 ,8-nahpthylendicarbonyl (radical P.1e with q = 1 , R = 3-NO2), 4- nitro-1 ,8-nahpthylendicarbonyl (radical P.1e with q = 1 , R = 4-NO2). The polymers of the invention bear at least one, e.g. on average 1 to 400, in particular 5 to 250 and especially 10 to 150 aliphatic polyester moieties P.2 per polymer molecule. In this context, the term "on average" is understood as the number average. Each of the moieties P.2 is bound to a nitrogen atom of the polyalkylene imine backbone via a carboxamide group. The term "aliphatic" means that the polyester groups do not contain aromatic rings. In partic ular, the polyester radicals bear repeating units having a C2-Cs-alkylene moiety, which is un substituted or carries 1 , 2, 3, or 4 CrC4-alkyl radicals. Within the polymers of the invention, the moieties P.2 may be identical or different. Preferably, they are identical.

The moieties P.2 will generally contribute by an amount of 50 to 98% by weight, in particular from 70 to 97% by weight or from 80 to 96% by weight to the total weight of the polymer. The weight ratio of the moieties P.2 to the polyalkylene imine is generally in the range from 1:1 to 98:1, in particular from 2:1 to 97:1 or from 3:1 to 50:1.

Preferably, the moiety P.2 is

P.2 wherein

# indicates the point of attachment to a nitrogen atom of the polyalkylene imine backbone, n is a number in the range of 2 to 100, in particular in the range of 3 to 50, especially in the range of 4 to 25;

A is independently from each other linear C2-Cs-alkylene, in particular linear C3-C6-al- kylene, where alkylene is unsubstituted or carries 1, 2, 3, or 4 CrC4-alkyl radicals, and R ^x is hydrogen, Ci-C2o-alkyl, C2-C2o-alkenyl, C(=0)-C ₂ -C ₂ o-alkenyl or C(=0)-Ci-C ₂ o-alkyl, wherein Ci-C2o-alkyl and C2-C2o-alkenyl in the last four radicals are unsubstituted or carry 1 or 2 OH groups, wherein C2-C2o-alkenyl has 1, 2, 3 or 4 olefinic C=C-double bonds, and wherein 1 , 2, 3, or 4 non-adjacent CH2 groups of Ci-C2o-alkyl may be replaced by O.

The variables A and R ^x in the at least one moiety (P.2) have in particular the following mean ings:

A is linear C3-C6-alkylene, more particularly 1 ,4-butandiyl or 1 ,5-pentandiyl or a combina tion thereof, and especially a combination of 1 ,4-butandiyl and 1 ,5-pentandiyl having a molar ratio of 1 ,4-butandiyl and 1 ,5-pentandiyl in the range of 1 :20 to 10:1;

R ^x is hydrogen, C(=0)-C ₆ -C ₂ o-alky or C(=0)-C ₆ -C ₂ o-alkenyl, wherein C6-C2o-alkyl and C ₆ - C2o-alkenyl are unsubstituted or carry 1 or 2 OH groups and where R ^x is especially C(=0)- Cio-C2o-alky or C(=0)-Cio-C ₂ o-alkenyl, wherein Cio-C2o-alkyl and Cio-C2o-alkenyl are unsub stituted or carry 1 or 2 OH groups. The polymers of the invention have a polyalkylenimine backbone, to which the at least one moiety P.1 and the at least one moiety P.2 are attached.

The polyalkylene imine may be linear or branched. The polyalkylene imine is in particular a linear or branched poly(C2-C4-alkyleneimine), more particularly a linear or branched polypro pylene imine, a linear or branched polyethylene imine-co-propylene imine) or a linear or branched polyethylene imine or a mixture thereof. Especially, the polyalkylene imine, which forms the backbone, is a linear or branched polyethylene imine.

The polyalkylene imine will usually have on average from 5 to 500, in particular from 10 to 250 especially from 20 to 100 alkylene imine repeating units, which corresponds to a number average molecular weight of the polyalkylene imine backbone in the range from about 200 to 20000 g/mol, in particular in the range from 400 to 10000 g/mol and especially in the range from 800 to 5000 g/mol.

The polyalkylene imine backbone will generally contribute by an amount of 1 to 25% by weight, in particular from 1.5 to 15% by weight or from 2 to 10% by weight to the total weight of the polymer.

Both moieties P.1 and P.2 are attached to nitrogen atoms of the polyalkylene imine backbone. As these nitrogen atoms are part of a carboxamide or carboximide group, their basicity is low compared to nitrogen atoms of a non-modified polyalkylene imine. It is apparent to a skilled person that polymers of the invention may have nitrogen atoms, which do not carry moieties P.1 and P.2. These nitrogen atoms are basic and susceptible to protonation orquaternization. Polymers of the invention, which have nitrogen atoms, which do not carry moieties P.1 and P.2, will usually have an amine number > 0 mg KOH/g, e.g. in the range from 2 to 150 mg KOH/g, in particular from 5 to 50 mg KOH/g.

As explained above, polymers of the invention, which have an amine number > 0 mg KOH/g, e.g. in the range from 2 to 150 mg KOH/g, in particular from 5 to 50 mg KOH/g are susceptible to protonation or quaternization, which means that at least some of the nitrogen atoms of the polyalkylene imine backbone that do not carry moieties P.1 or P.2, hence amino groups of the polyalkylene imine backbone, can be transformed into cationic, i.e. into protonated or quaternized amino groups. Therefore, one embodiment of the invention relates to polymers, wherein the polyalkylene imine backbone in addition to the moieties P.1 and P.2 has proto nated or quaternized amino groups. In this embodiment, the amount of protonated or quater nized amino groups is generally from 0.01 to 0.5 mol/kg. Another embodiment of the invention relates to polymers, wherein the polyalkylene imine backbone in addition to the moieties P.1 and P.2 does not have quaternized amino groups. In this embodiment, the amount of quaternized amino groups is less than 0.01 mol/kg.

Depending of the type of amino nitrogen atom (primary, secondary, or tertiary), the protonated or quaternized amino groups can be described by the following formulae Q1 , Q2 and Q3:

Q1 Q2 Q3 where R ^k indicates a H (protonized groups Q1 , Q2 and Q3) or an optionally substituted hy drocarbon radical such as alkyl, aryl, arylalkyl or cycloalkyl (quaternized groups Q1, Q2 and Q3).

Preferably, R ^k is selected from the group consisting of hydrogen,

CrC2o-alkyl, which is unsubstituted or carries 1 or 2 OH groups and wherein 1 , 2, 3, or 4 non-adjacent CH2 groups of Ci-C2o-alkyl may be replaced by O,

C2-C2o-alkenyl, which has 1 , 2, 3 or 4 olefinic C=C-double bonds and which is unsubsti tuted or carries 1 or 2 OH groups, aryl, such as phenyl or naphthyl, where the aryl part is unsubstituted or carries 1 , 2, 3, 4 or 5 substituents, which are selected from the group consisting of halogen, OH, NO2, COOH, Ci-C ₄ -alkyl, Ci-C ₄ -alkoxy, CONH ₂ , NH-CHO, and NH-(C=0)-Ci-C ₄ -alkyl, and aryl-CH2, such as benzyl, 1-naphthylmethyl or 2-naphthylmethyl, where the aryl part is unsubstituted or carries 1 , 2, 3, 4 or 5 substituents, which are selected from the group con sisting of halogen, OH, NO2, COOH, Ci-C ₄ -alkyl, S-Ci-C ₄ -alkyl, S(0) ₂ -Ci-C ₄ -alkyl, Ci-C ₄ - alkoxy, CONH ₂ , NH-CHO, and NH-(C=0)-Ci-C ₄ -alkyl.

In particular R ^k is selected from the group consisting of hydrogen,

Ci-Cio-alkyl, which is unsubstituted or carries 1 or 2 OH groups; benzyl, where the phenyl ring part is unsubstituted or carries 1 , 2 or 3 substituents, which are selected from the group consisting of halogen, OH, NO2, Ci-C ₄ -alkyl and Ci-C ₄ - alkoxy.

The positive charge of the quaternized or protonized groups is neutralized by suitable anions including halogenide, such as chloride or bromide, sulfate (S0 ₄ ² -), hydrogensulfate (HS0 ₄ -), alkyl carboxyl ate, such as acetate or propionate, arylcarboxylates, where the aryl ring is unsubstituted or optionally substituted by Ci-C^alkyl, CrC4-alkoxy, NO2, hydroxyl or halo gen, such as benzoate, CrC4-alkylbenzoate, 2-hydroxybenzoate, 4-hydroxybenzoate, 1- naphthoate, 2-naphthoate, 2-hydroxy-3-naphthoate, 8-hydroxy- 1-naphthoate, CrC4-alkyl- sulfonate, such as methylsulfonate or ethylsulfonate, CrC4-alkylsulfate such as methyl sul fate or ethyl sulfate, arylsulfonates, where the aryl ring is unsubstituted or optionally substi tuted by CrC4-alkyl, CrC4-alkoxy, NO2, hydroxyl or halogen, such as benzene sulfonate, toluene sulfonate or naphthalin sulfonate.

In a preferred embodiment, the at least one monoamine functionalized polyalkyleneoxide is methoxypolyethyleneglycolamine, methoxypolypropyleneglycolamine, methoxypoly(eth- ylene-co-propylene)glycolamine.

In a preferred embodiment, the at least one aromatic compound is selected from isatoic an hydride and naphthalic anhydride.

Another aspect of the presently claimed invention is directed to a method for preparing the polymer composition of the present invention comprising the steps of

(i) obtaining at least one polyacrylic block copolymer and at least one aromatic based poly alkyleneoxide as defined above, and

(ii) mixing 10 wt% to 90 wt% of the at least one polyacrylic block copolymer and 10 wt% to 90 wt% of the at least one aromatic based polyalkyleneoxide, both based on the total weight of the composition, to obtain the polymer composition, wherein acrylate monomer, ethylenically unsaturated monomer, R ¹ , R ² , R ³ , X, W1, W2, T, P, A and Q are as defined above.

In an embodiment, the step (ii) of mixing is carried out at a temperature in the range from 30°C to 120°C for a time period in the range from 0.5 h to 24 h.

Yet another aspect of the presently claimed invention is directed to a liquid composition in the form of a dispersion comprising a. a particulate solid material selected from pigments, silica and fillers, and b. a liquid diluent comprising the polymer composition according to the presently claimed invention.

In a preferred embodiment, the liquid composition is a millbase.

In a preferred embodiment, the particulate solid material is a pigment.

In a preferred embodiment, the organic pigment (or a mixture of organic pigments), the poly mer composition according to the presently claimed invention as a dispersant and a milling liquid such as water (or a mixture of miling liquids), and, optionally, one or more milling addi tives and/or one or more surface treatment additives are combined in any order. Preferably, all such components are combined prior to the milling such that the total solids content in the milling mixture is at least about 10% by weight (more preferably 20 to 50% by weight).

Milling is carried out using known dry milling methods, such as jet milling, ball milling, and the like, or known wet-milling methods, such as salt kneading, sand milling, bead milling, and the like.

Another aspect of the presently claimed invention is directed to a coating composition com prising the dispersant composition of the presently claimed invention.

In a preferred embodiment, the dispersant composition is a millbase.

It is observed that the liquid compositions comprising the polymer composition of the pres ently claimed invention have a low millbase viscosity.

In a preferred embodiment, the dispersant composition is a millbase comprising a black pig ment.

In a preferred embodiment, the coating composition further comprises at least one additive selected from pigment pastes, binders, fillers, solvents, defoamers, neutralising agent, wet ting agent, pigment dispersing agents, preservatives and water.

In a preferred embodiment, the coating composition is water based coating composition com prising waterborne acrylic copolymer dispersion.

Another aspect of the presently claimed invention is directed to use of the polymer composi tion of the presently claimed invention as a dispersant in a coating composition.

Pigments prepared according to the presently claimed invention are suitable for use in a va riety of pigment applications, particularly in view of their excellent dispersibility without sacri ficing color properties in wet and/or dried coating systems. Pigments produced from the pro cesses of the present invention are highly dispersible without sacrificing color properties in wet and/or dried coating systems. For example, the conditioned pigments can be dried and used as components in coating systems. Conditioned pigments prepared by the processes of the present invention are readily dispersible, for example, in aqueous coating systems. The conditioned pigments may be mixed with other materials such as pigment formulations (in cluding inorganic white pigments, such as titanium dioxide (rutile), cement, inorganic pig ments, flushed pastes with organic liquids or pastes, pigment dispersions with water, dispersants, and, if appropriate, preservatives), coating compositions (including paints, pref erably automotive paint, electronic coating paints, physically or oxidatively drying lacquers, stoving enamels, reactive paints, two-component paints, solvent- or water-based paints, emulsion paints for weatherproof coatings and distempers, printing ink, including inkjet inks, or colored paper).

The presently claimed invention offers one or more of the following advantages:

1) The polymer compositions of the presently claimed invention provide coating compositions having a low millbase viscosity.

2) The coating compositions containing the polymer composition of the presently claimed invention provide coating compositions provide coats having improved surface properties such as low crater ranking.

3) The polymer compositions of the presently claimed invention do not adversely affect the color properties of the coating compositions.

4) A low viscosity of the polymer composition of the presently claimed invention leads to a short process time for preparation of the coating compositions and for application of coats on substrates.

5) The polymer composition of the presently claimed invention has a lower cost as compared to the polyacrylic block copolymer alone due to a low cost of the aromatic based polyalkylene- oxide.

In the following, there are provided a list of embodiments to further illustrate the present dis closure without intending to limit the disclosure to specific embodiments listed below.

1. A polymer composition comprising a) at least one polyacrylic block copolymer in the range from 10 to 90 wt% based on the total weight of the composition, wherein the at least one polyacrylic block copolymer is obtainable by reacting i) polymer (A) obtainable by controlled free radical polymerization of at least one acrylate monomer selected from C1-C6 alkyl esters of acrylic acid, C1-C6 alkyl esters of methacrylic acid, hydroxy C1-C6 alkyl esters of acrylic acid and hydroxy C1-C6 alkyl esters of meth acrylic acid, in the presence of either a 1 or in presence of a2, wherein a1 is at least one nitroxylether of formula (I)

R ¹ R ² NOX (I), and a2 is at least one stable free nitroxyl radical of formula (II)

R ¹ R ² NO (II); wherein

R ¹ and R ² are independently selected from substituted or unsubstituted, linear or branched C ₅ -C ₁₈ alkyl, or R ¹ and R ² together with the nitrogen atom to which they are attached form an unsubstituted or substituted 5- to 10-membered aliphatic ring comprising 1 to 3 heteroatom(s) selected from nitrogen and oxygen, and

X is selected from -CH ₂ -phenyl, - CH(CH3)-phenyl, -C(CH3)2-phenyl, -(C5-C6cycloalkyl) ₂ C- CN, -(CH ₃ ) ₂ CCN, -CH ₂ CH=CH ₂ , -CH ₃ CH-CH=CH ₂ , -(Ci-C ₄ alkyl)CR ³ -C(0)-phenyl, -(C C ₄ )alkyl-CR ³ -C(0)-(Ci-C ₄ )alkoxy, -(Ci-C ₄ )alkyl-CR ³ -C(0)-(CrC ₄ )alkyl, -(Ci-C ₄ )alkyl-CR ³ - C(0)-N-di(Ci-C ₄ )alkyl, -(Ci-C ₄ )alkyl-CR ³ -C(0)-NH(CrC ₄ )alkyl, and -(Ci-C ₄ )alkyl-CR ³ - C(0)-NH ₂ , wherein R ³ is hydrogen or (CrC ₄ )alkyl; with ii) at least one ethylenically unsaturated monomer selected from a Cs-C ₂ o vinylaromatic, an ethylenically unsaturated nitrile, acrylamide, a vinyl halide, a vinyl ether of an C ₁ -C ₁₀ alcohol and an C ₂ -Cs aliphatic hydrocarbon having one or two double bonds; and b) at least one aromatic based polyalkyleneoxide in the range from 10 to 90 wt% based on the total weight of the composition, wherein the at least one aromatic based polyalkyleneoxide is obtainable by reacting

(i) at least one monoamine functionalized polyalkyleneoxide of formula (III)

T-(0-P) _n -NH ₂ (III) wherein P is a substituted or unsubstituted, linear or branched CrC ₄ alkylene, ora mixture of CrC ₄ alkylene, and

T is selected from substituted or unsubstituted, linear or branched Ci-C ₂₂ alkyl, substituted or unsubstituted Ci-C ₂₄ alkylaryl, and substituted or unsubstituted Ci-C ₂₄ dialkylaryl and n is an integer in the range of 1 to 150; with

(ii) at least one aromatic compound of the formula (IV) wherein

Q is a chemical bond or a divalent moiety selected from -0-, -NH- and -S-,

A is an unsubstituted or substituted aromatic group selected from the formula wherein # indicates the point of attachment to the rest of the molecule, and q is 0, 1 , 2, 3 or 4,

Ris independently selected from halogen, NO2, OH, Ci-C4-alkyl, CrC4-alkoxy, CONH2, NH-CHO, NH-Ci-C ₄ -alkyl, and NH-(C=0)-Ci-C ₄ -alkyi.

2. The polymer composition according to embodiment 1 , wherein the at least one acrylate monomer is n-butyl acrylate, or 2-ethyl hexyl arylate.

3. The polymer composition according to embodiment 1 or 2, wherein the at least one ni- troxylether is a compound of formula (la).

4. The polymer composition according to any of embodiments 1 to 3, wherein the at least one ethylenically unsaturated monomer is selected from isoprene, 1 ,3-butadiene, a-Cs- Ci ₈ -alkene, 4-vinyl-pyridine or pyridinium-ion, 2-vinyl-pyridine or pyridinium-ion, vinyl-im idazole or imidazolinium ion, dimethylacrylamide, 3-dimethylaminopropylmethacrylamide, styrene, a-methyl styrene, p-methyl styrene, p-tert-butyl-styrene and a compound of formula CH ₂ =C(Ra)-(C=Z)-R _b , wherein R _a is hydrogen or methyl,

Z is oxygen or sulfur, and

R _b is selected from NH2, 0(Me ⁺ ), unsubstituted Ci-Cis-alkoxy, C2-Cioo-alkoxy interrupted by at least one nitrogen and/or oxygen atom or hydroxy-substituted C1-C18 alkoxy, unsub stituted C1-C18 alkylamino, di(Ci-Cie alkyl)-amino, hydroxy-substituted C1-C18 alkylamino or hydroxy-substituted di(Ci-Cie alkyl)amino, -0-CH2-CH2-N(CH3)2 and -O-CH2-CH2- N ⁺ H(CH3)2 An-; wherein An- is an anion of a monovalent organic or inorganic acid, and Me is a monovalent metal atom or the ammonium ion. The polymer composition according to any of embodiments 1 to 4, wherein the at least one ethylenically unsaturated monomer is selected from 2-vinylpyridine, 4-vinyl-pyridine, 3-diemthylaminopropylmathylacrylamide and dimethlyaminoethyl methacrylate. The polymer composition according to embodiments 1 to 5, wherein the at least one pol yacrylic block copolymer is subjected to functionalization with at least one alcohol selected from W1 and W2, wherein,

W1 is R ⁴ -OH, wherein R ⁴ is a substituted or unsubstituted, linear or branched C8-C36 alkyl;

W2 is at least one polyether alcohol of formula G-(0-Q) _n -OH wherein G is a substituted or unsubstituted, linear or branched C1-C4 alkylene, and Q is selected from substituted or unsubstituted, linear or branched C1-C22 alkyl, substi tuted or unsubstituted C1-C24 alkylaryl, and substituted or unsubstituted C1-C24 dialkylaryl, and n is an integer in the range of 1 to 150. The polymer composition according to embodiment 6, wherein the at least one polyether alcohol is methoxypolyethyleneglycol with the molecular weight (M _w ) of 200-1000 g/mol. The polymer composition according to any of embodiments 1 to 7, wherein the at least one monoamine functionalized polyalkyleneoxide is methoxypolyethyleneglycolamine, methoxypolypropyleneglycolamine, methoxypoly(ethylene-co-propylene)glycolamine. The polymer composition according to any of embodiments 1 to 8, wherein the at least one aromatic compound is selected from isatoic anhydride and naphthalic anhydride. A method for preparing the polymer composition of any of embodiments 1 to 9 comprising the steps of

(i) obtaining at least one polyacrylic block copolymer and at least one aromatic based polyalkyleneoxide as defined in any of embodiments 1 to 9, and

(ii) mixing 10 wt% to 90 wt% of the at least one polyacrylic block copolymer and 10 wt% to 90 wt% of the at least one aromatic based polyalkyleneoxide, both based on the total weight of the composition, to obtain the polymer composition, wherein acrylate monomer, ethylenically unsaturated monomer, R ¹ , R ² , R ³ , X, W1 , W2, T, P, A and Q are as defined in embodiments 1 to 9. 11. The method according to embodiment 10, wherein the step (ii) of mixing is carried out at a temperature in the range from 30°C to 120°C for a time period in the range from 0.5 h to 24 h.

12. A liquid composition in the form of a dispersion comprising a. a particulate solid material selected from pigments, silica and fillers, and b. a liquid diluent comprising the polymer composition according to any of embodi ments 1 to 9.

13. A coating composition comprising the liquid composition according to embodiment 12.

14. The coating composition according to embodiment 13 further comprising at least one ad ditive selected from pigment pastes, binders, fillers, solvents, defoamers, neutralising agent, wetting agent, pigment dispersing agents, preservatives and water.

15. Use of the polymer composition according to any of embodiments 1 to 9 as a dispersant in a coating composition.

While the presently claimed invention has been described in terms of its specific embodi ments, certain modifications and equivalents will be apparent to those skilled in the art and are intended to be included within the scope of the presently claimed invention.

Examples

The presently claimed invention is illustrated in detail by non-restrictive working examples which follow. More particularly, the test methods specified hereinafter are part of the general disclosure of the application and are not restricted to the specific working examples.

Materials EFKA® 2550 defoamer for various water-based coating systems and pigment concentrates;

Hydro pa I at® WE 3370 fluorcarbon modified polyacrylate used as wetting agent; available from BASF Se.

Setaqua® 6801 waterborne acrylic copolymer dispersion suitable for OEM metal or plastic basecoats available from Allnex.

Jeffamine® M 2070 a relatively hydrophilic polyether monoamine of approximately 2000 molecular weight available from Huntsman.

Methods

The molecular weight (M _w ) was determined according to DIN 55672-1. The acid number was determined according to DIN 53402:1990-09. The amine number was determined according to DIN 53176:2002-11.

The viscosity was determined by analogy to DIN 53019-1 :2008-09, using a Thermo Haake RheoStress ^® 600 equipment under the CR mode at 22°C and a shear rate of 1 sec- ¹ (Spindle CP50).

Jetness (blackness, My) was determined according to DIN 55979.

Polyacrylic block copolymer dispersant

Intermediate A1 was prepared according to EP1861429B1 Example A3 (Poly(n-BA-MPEGA- b-4-VP).

Intermediate A2 was prepared according to W008006723A1 Example A15 ((Poly(n-BA- MPEGA-b-4-DMAPMA).

Aromatic based polyalkyleneoxide dispersant Intermediate B1 :

A 300 ml_ four-necked flask equipped with a stirrer, a thermometer and maintained under nitrogen atmosphere, was charged with 150 g Jeffamine® M 2070 (MW of 2000 g/mol), 11.6 g isatoic anhydride with 0.2 g 1 ,4-diazabicyclo[2.2. 2]octane (DABCO). The reaction mixture was stirred at room temperature for 1h and then the reaction temperature was slowly in creased to 100°C and followed by stirring under these conditions for 5h. Intermediate B1 was obtained as a brownish liquid having an amine number of 23 mg KOH/g.

Intermediate B2:

A 300 ml_ four-necked flask equipped with a stirrer, a thermometer and maintained under nitrogen atmosphere, was charged with 150 g Jeffamine® M 2070 (MW of 2000 g/mol), 14.1 g 1 ,8-naphthalic anhydride. The reaction mixture was stirred at 100°C for 5h. Intermediate B2 was obtained as a brownish liquid having an acid number of 20 mg KOH/g.

Intermediate B3:

A 300 ml_ four-necked flask equipped with a stirrer, a thermometer and maintained under nitrogen atmosphere, was charged with 150 g Jeffamine® M 2070 (MW of 2000 g/mol), 14.1 g 1,8-naphthalic anhydride. The reaction mixture was stirred at 100°C for 2h. Then, the reac tion mixture was heated to 150°C under vacuum for 5h. Intermediate B3 was obtained as a brownish liquid having an acid number of 2 mg KOH/g.

Dispersant:

The dispersants 1-6 were prepared by blending intermediates A and B mentioned in Table 1 in specified amounts at 80°C under stirring for 3h.

Table 1: Preparation of Dispersants 1-6

Properties of Dispersants i) Millbase

In order to test the dispersion effect of the obtained samples, resin free pigment concentrates (millbase) were prepared according to the Formulation 1. The millbase was dispersed in Scandex Shaker for 4 h with the help of glass beads. Afterwards the millbase was filtered and stored at room temperature overnight.

The performance of the dispersants was generally very good with low millbase viscosity (Table 2).

Formulation 1 : Water-based Pigment Concentrates ii) Paint

The paint was prepared by mix of 2.0 g millbase into 8.0 g let-down system (Formulation 2) via Dispermat® for 2 min at 2000 rpm.

Formulation 2. Let-down system iii) Properties of paint

The paint was applied on polyester film with a 75 pm film thickness. The wet films stand at room temperature for 30 min, followed by 90°C for 30 min. The dried film was generally very good with satisfactory results (Table 3).

Table 3: properties of the dispersants

*: a qualitative ranking from 1 (no visible craters) to 5 (many craters)