WO2014106729A1 - Process for preparing a polymer, polymer, dispersion, ink, and use - Google Patents

Abstract

A process for preparing a polymer comprising reacting at least the compounds in components i) and ii): i) a compound of the Formula (1); wherein: R¹ to R⁴, A¹ and A², Z and L are as defined in claim 1; ii) a compound of the Formula (2): wherein T, D, E, R⁵ and R⁶ and n are as defined in claim 1. The polym useful for dispersing particulate solids, e.g. pigments in ink jet printing inks.

Description

PROCESS FOR PREPARING A POLYMER, POLYMER, DISPERSION, INK,

AND USE

This invention relates to polymers, to processes for preparing polymers, to dispersions and inks containing the polymers and to uses of such polymers, dispersions and inks.

Inks are often of one of two types, depending on the type of colorant used. Dye-based inks often comprise a dye dissolved in a liquid vehicle. Pigment-based inks typically comprise a particulate pigment dispersed in a liquid vehicle. Pigment-based inks generally have better ozone-fastness and light-fastness than dye-based inks. However, because the pigment is in the form of fine particles, there is a tendency for the particles to agglomerate or flocculate during ink storage or in use. Such agglomeration or flocculation before an ink has been printed onto a substrate is highly undesirable, particularly for ink jet printing inks, because such inks have to pass through very small printhead nozzles which are susceptible to blockage by any oversized particulate matter. Thus, in the ink jet field, a great deal of effort has been spent attempting to provide sub micron sized pigment dispersions and increase the colloidal stability of these pigment dispersions.

It is desirable for pigment-base inks to be storage stable and provide prints having a high optical density (OD), good durability (e.g. good dry-, wet- and highlighter rub fastness), especially when printed onto plain paper.

Many of the dispersants currently used to provide pigment-based inks require significant and undesirably high amounts of organic solvent to assist in dissolving/dispersing the dispersant, for example when the pigment is being comminuted (e.g. milled) or dispersed.

It is desirable for dispersant used to disperse pigments to assist the comminution process. Quicker comminution (e.g. milling) to submicron particles sizes saves substantial energy and it may also result in less pigment particles having a particles size markedly smaller than the target size.

According to a first aspect of the present invention there is provided a process for preparing a polymer comprising reacting at least the compounds in components i) and ii):

i) a compound of the Formula (1 );

Formula (1 )

wherein:

R¹ to R⁴ are each independently H or an optionally substituted alkyl, aryl or heterocyclyl group;

A¹ and A² each independently are an optionally substituted divalent organic linking group; and

Z is a halogen, -OH, -S-L, -O-L, a nitrogen-containing heterocyclic group, -NH₂, -NHL, or -NL₂, wherein each L independently is an optionally substituted alkyl, aryl or heterocyclyl group;

ii) a compound of the Formula (2):

Formula (2) each T independently is a halogen or an OH group;

each D and E independently is optionally substituted divalent organic linking group;

each R⁵ and R⁶ independently is H or an optionally substituted alkyl, aryl, heterocyclyl group or R⁵ and R⁶ join together so as to form a cyclic group; and

n is at least 1 .

In this description the words "a" and "an" mean one or more unless indicated otherwise. Thus, for example, "a" compound of Formula (1 ) means one or more compounds of Formula (1 ).

Whilst the compounds as described in the first aspect of the present invention have been drawn in one structural formula the compounds and the scope of the claims are also intended to cover tautomers thereof. The optionally substituted divalent organic linking groups represented by A¹ and A² are preferably each independently an alkylene, cycloalkylene, arylene, or heterocyclylene group, each of which may be optionally interrupted by and optionally substituted by other groups. Of these optionally substituted arylene and alkylene groups are preferred. The optionally substituted heterocyclylene groups may be aromatic or non-aromatic.

The optionally substituted divalent organic linking groups optionally comprise two or more groups selected from alkylene, arylene and heterocyclylene groups.

The optionally substituted divalent organic linking groups optionallycomprise -O-, -S-, -CO2-, -NHCO-, -SO2- and/or -NHSO2- groups. Preferably A¹ and A² are each independently an optionally substituted arylene group, an optionally substituted alkylene group, or a combination thereof.

Preferred optionally substituted arylene groups are optionally substituted naphthylene groups, more preferably optionally substituted phenylene groups. When A¹ is an optionally substituted phenylene group the groups NHR¹ and NR³ shown in Formula (1 ) are in an ortho, meta or more preferably a para position relative to each other. When A² is an optionally substituted phenylene group the groups NHR² and NR⁴ shown in Formula (1 ) are in an ortho, meta or more preferably a para position relative to each other. When A¹ or A² is an optionally substituted alkylene group it is preferably an optionally substituted C1-30 alkylene group, especially an optionally substituted C1-20 alkylene group and most especially an optionally substituted C2-8 alkylene group. The alkylene groups may be cyclic, branched or linear. Preferred examples of optionally substituted alkylene groups include -(CH₂)i-2o- groups, examples of which include -(CH₂)2- - (CH₂)3-, - (CH₂)₄-, - (CH₂)₆- and - (CH₂)₈-.

When A¹ or A² is an optionally substituted cycloalkylene group it is preferably an optionally substituted cyclohexylene group.

A¹ and A² comprises an optionally substituted alkylene group and an optionally substituted arylene group it is preferably an optionally substituted benzyene group (-CH₂-phenylene-) or xylylene group (-CH₂-phenylene-CH₂-).

In view of the foregoing, preferably A¹ and A² are independently selected from C-i-30 alkylene, phenylene, naphthylene and xylylene groups, each of which may be optionally substituted. More preferably A¹ and A² are independently selected from C1-30 alkylene groups and phenylene groups, each of which may be optionally substituted, preferred examples of which are mentioned above.

Preferred specific examples of A¹ and A² groups are *ΟΗ₂ΟΗ₂*, *CH₂CH*CH₃, *CH₂CH*CH₂CH₃ and ortho, para and meta-phenylene, wherein the asterisks mark the point of attachment of the groups in the compound of Formula

(1 ). The groups A¹ and A² may be different but more preferably they are the same.

A¹ and A² may be optionally substituted with one or more optional substituents, for example water-dispersing substituents and/or substituents which are not water-dispersing.

In preferred embodiments A¹ and/or A² is/are unsubstituted. Examples of substituents which are not water-dispersing include -NO2, CN, halo (especially CI, F, Br and I), -NHC(0)Ci_-6-alkyl, -S0₂NH-Ci_-6alkyl, -S0₂Ci_-6-alkyl, -Ci_-6-alkyl, -OCi_-6- alkyl, -OC(0)Ci-6-alkyl and polypropyleneoxide ending in a d-6-alkyl group. These optional substituents are not water-dispersing.

Examples of substituents which are water-dispersing include ionic and non- ionic water-dispersing groups.

Preferred ionic water-dispersing substituents include acid groups, especially carboxylic acid, sulphonic acid and phosphorus containing acids (especially phosphoric and more especially phosphonic acid). Carboxylic and phosphonic acid groups are especially preferred as they have been found to impart the particularly good dispersant characteristics.

Non-ionic water-dispersing substituents include polyethyleneoxy and mixed poly(ethyleneoxy-propyleneoxy) groups. These are preferably terminated in C1-20 alkyl groups, more preferably methyl or ethyl groups.

When A¹ and A² carry one or more substituents, it is preferred that all of such substituents are free from thiol, amine, hydrazo (H₂NNH-) and hydroxyl (HO-) groups (apart from the NR¹, NR², NR³ and NR⁴ groups shown in Formula (1 )). This preference arises because the absence of such substituents is believed to reduce the likelihood of unwanted gelation in the subsequent reaction with the compound of Formula (2).

When R¹, R², R³, R⁴, R⁵, R⁶, L, D and E are substituted, the substituents are each independently selected from those mentioned above in relation to A¹ and A².

When any one of the groups R¹ to R⁴ is an optionally substituted alkyl group, it is preferably optionally substituted C1-20 alkyl (especially methyl or ethyl).

When any one of the groups R¹ to R⁴ is an optionally substituted aryl group it is preferably optionally substituted phenyl or naphthyl.

When any one of the groups R¹ to R⁴ is an optionally substituted heterocyclyl it may be aromatic (heteroaryl) or non-aromatic. When any one of the groups R¹ to R⁴ is heterocyclyl it preferably comprises a 5- or 6- membered ring containing from 1 to 3 atoms selected from N, S and 0 in the ring (the remaining ring atoms being carbon atoms). Preferred examples of optionally substituted heterocyclyl groups include optionally substituted pyrrolyl, thiophenyl, furanyl, pyridyl, pyrimidyl, pyrazinyl, triazinyl, imidazolyl, thiazolyl, oxazolyl and pyrazolyl.

Preferably, R¹ and R² are both H because it can lead to improvements in the speed and yield of reaction with the compound of Formula (2).

Preferably, R³ and R⁴ are each independently selected from methyl, ethyl and H, more preferably R³ and R⁴ are both H.

Preferred halogens represented by Z include F, CI, Br and I. Of these, CI is especially preferred. Compounds of Formula (1 ) wherein Z is a halogen are especially suitable for reaction with the compounds of Formula (2) and then post modification with a compound which preferably introduces one or more water- dispersing groups.

Examples of nitrogen-containing heterocyclic groups which may be represented by Z include optionally substituted pyrrole, pyrrolidine, imadazole, imadazolidine, pyrazole, pyrazolidine and morpholine. In these cases the Z group is preferably attached to the triazine ring shown in Formula (1 ) via a nitrogen atom in the heterocycle.

Preferably Z is -NHL or -NL₂ (the latter being N carrying two L groups, which may alternatively be written -N(L)₂). Preferred Z groups of the formula - NHL or -NL₂ include:

-NHCH2CH2-SO3H (taurine residue), -NH-phenylene-SO₃H (sulfanilic acid residue), -NHCH₂CO₂H (glycine residue), -NHCH(CH₃)CO₂H (alanine residue), - NH-CH(CH₂CO₂H)CO₂H (aspartic acid residue), -N(CH₂CO₂H)₂ (imino diacetic acid residue), -NHphenyene-CO₂H (amino benzoic acid residue), -NH-phenylene- (CO₂H)₂ (amino dibenzoic acid residue), -NH-phenylene-(CO₂H)₃ (amino tribenzoic acid residue), -NHCH₂PO₃H₂ (aminomethyl phosphonic acid residue), - NH(CH₂PO₃H₂)₂ (iminodimethyl phosphonic acid residue), -NH-phenylene-PO₃H₂ (amino phenyl phosphonic acid residue) and -NH-phenylene-(PO₃H₂)₂ (aminophenyl diphosphonic acid residue).

In one embodiment the process comprises two or compounds of Formula

(1 ). In this case, preferably, at least some of the Z groups comprise one or more water-dispersing groups, for example any of the water-dispersing groups mentioned and preferred above. In some embodiments it is desirable that the Z groups in all of the compounds of Formula (1 ) have at least one water-dispersing group. In an alternative embodiment, the process comprises two or compounds of Formula (1 ) and in at least one of which Z comprises one or more water-dispersing groups and in at least one of which Z is free from water-dispersing groups. Preferred Z groups which are free from water-dispersing groups include -OH, - NH₂, -NH-Ci_-2o-alkyl and -NH-aryl (especially -NH-phenyl and -NH-naphthyl). Preferably L comprises one or more water-dispersing groups, e.g. one or more of the water-dispersing groups described above in relation to A¹ and A². In some embodiments all the groups represented by L comprise at least one water- dispersing group. In some embodiments some of groups represented by L comprise a water-dispersing groups and some represented by L are free from water-dispersing groups.

Preferred groups represented by L comprising a water-dispersing group include:

-CH₂-W, - CH2CH2-W, -CH2CH2CH2-W, -CHWCH3, -CH2CHWCH3, -GW1-3

Wherein each W independently is a water-dispersing groups and G is an aryl or heterocyclyl group (preferably one of the heterocyclyl groups described above in relation to the definition of R¹ to R⁴. Preferably each W independently is alkyl-terminated poly (ethyleneoxy), sulfonic acid, carboxylic acid or more preferably a phosphorus-containing acid (especially phosphonic acid).

Where a represented by L comprises more than one water-dispersing groups these may be different types of water-dispersing groups but are preferably the same type of water-dispersing group.

Especially preferred compounds of Formula (1 ) are those wherein:

A¹ and A² are each independently selected from C1-30 alkylene, phenylene, naphthylene and xylylene;

R¹ and R² are H;

R³ and R⁴ are independently selected from methyl, ethyl and H; and Z is a halogen, -NHL or NL₂ wherein each L independently is as hereinbefore defined.

When the compounds of Formula (1 ) or (2) comprise ionic groups (e.g. ionic water-dispersing groups) these may all be in ionised form, unionised form some of the ionic groups are in ionised form and others are in unionised form. Acidic ionic groups may be in the form of the free acid (e.g. -CO2H, -SO3H and -PO3H2) or in the form of partial or completely neutralised salts. Preferred salts include those with the alkali metal ions (especially sodium, lithium and potassium), ammonia (ammonium salts), organic amines and organic alcohol-amines (e.g. ethanolamine).

The compounds of Formula (1 ) may be conveniently prepared by reacting a trihalo triazine (especially cyanuric chloride) in a stepwise manner with:

(a) when Z is not halo, with a compound of formula Z-H

(b) an amine of formula HNR¹-A¹-NR³H; and

(c) an amine of formula HNR -A²-NR²H;

wherein R¹ , R², R³, R⁴, A¹ , A² and Z are as hereinbefore defined (except that Z is not a halogen). Preferably step (a) is performed first. Thus the order of the above- mentioned steps is preferably (a), (b) then (c), or (a), (c) then (b).

The reactions are preferably performed at a temperature of 0 to 100°C. As the halogens remaining on the triazine ring become less reactive as they reduce in number, typically the first reaction (e.g. step (a)) is performed at 0 to 20°C, the second reaction (e.g. step (c) or (b)) is performed at 20 to 40°C and the third reaction, when there is only one halogen remaining on the triazine ring, is typically performed at 40 to 100°C.

The pH during these reactions is preferably from 4 to 10, more preferably from 4 to 8. pH adjustment is preferably achieved by the addition of a base. Examples of preferred bases include potassium carbonate and potassium hydroxide. The reaction time for each step ((a), (b) and (c)) is preferably from 30 minutes to 10 hours, especially 1 to 8 hours.

For compounds of Formula (1 ) wherein Z is a halogen, no reaction step is required to introduce the halogen group because it is already present in the starting trihalo triazine.

Compounds of Formula (1 ) wherein Z is -OH may be prepared by hydrolysis of the corresponding compound wherein Z is a halogen.

Compounds of Formula (1 ) wherein Z is -O-L, -S-L, -NHL, -NL₂ or a nitrogen-containing heterocycle may be prepared by reacting the corresponding compound wherein Z is a halogen with an alcohol of the formula H-O-L, a thiol of formula H-S-L or an amine of formula NH₂L or HNL₂, wherein L is as hereinbefore defined, or with a nitrogen-containing heterocycle comprising an NH group (e.g. morpholine), as the case may be.

Preferred compounds of the Formula NH₂L and NHL₂ have one or more water-dispersing groups. Preferred examples of which include: taurine, sulfanilic acid, glycine, (beta)-analine, aspartic acid, imino diacetic acid, amino benzoic acid, amino-phthalic acid, 5-amino 1 ,2,3-benzene tricarboxylic acid, amino methyl phosphonic acid, alendronic acid, iminodimethyl phosphonic acid and amino phenyl phosphonic acid. Alternatively, the compound of the Formula NH₂L and

HNL₂ may contain no water-dispersing groups in which case the preferred compounds are primary and secondary amines, especially primary and secondary C-i-30 aliphatic amines (e.g. propylamine and butylamine) and aryl amines (e.g. benzylamine).

Preferably step (a) in which the trihalo triazine is reacted with the compound of Formula H-Z is performed first, then reaction of the resultant di halo triazine with compounds of formula RxNR¹-A¹-NR³H and HNR -A²-NR²Rx is performed sequentially in either order, wherein R¹, R², R³, R⁴, A¹, A² and Z are as hereinbefore defined and Rx is H or, more preferably, a protecting group. Any protecting group suitable for amines can be used as Rx, but acyl groups are particularly suitable. Preferred acyl groups are of the Formula -

especially -C(=0)-methyl and -C(=0)-ethyl.

One example of a compound of the formula RxNR¹-A¹-NR³H is 4-amino acetanilide.

The pH during the reaction of step (b) and the time for the reaction in step (b) are as mentioned above.

In steps (a), (b) and (c) the reactions are preferably performed in a liquid medium. The preferred liquid medium is sulfolane, N-methyl pyrrolidone or especially water, or a liquid medium comprising two or more thereof.

The R_x protecting groups can be readily removed to typically provide a H group. A preferred deprotection reaction uses acid cleavage or, more preferably, base cleavage.

Base cleavage is especially suitable when Rx is an acyl group. Suitable bases include alkali metal hydroxide, organic amines and alkanolamines and the pH for base cleavage is preferably around 12. Suitable acids for removing Rx groups include sulphuric, nitric, phosphoric and especially hydrochloric acid. Sufficient acid is normally introduced to provide a pH of less than 4, especially about 2. The deprotection reaction is preferably performed in an aqueous liquid medium.

Preferably, the deprotection reaction is performed after all of steps (a), (b) and (c) have been performed. Optionally the process comprises one or more purification steps. For example, one may perform a purification step between steps (a) and (b) and/or between steps (b) and (c) and optionally before and/or after any deprotection step. Suitable purification steps include acid precipitation, filtration and washing and/or membrane filtration (e.g. ultrafiltration).

Preferably Z is a halogen. Preferred halogens include F, CI, Br and I. Of these, CI is especially preferred. Compounds of Formula (2) wherein T is a halogen are especially suitable for reaction with the compounds of Formula (1 ).

The optionally substituted divalent organic linking groups represented by each E group may, independently, be any of the groups mentioned above for A¹ and A². Preferably however, each E group independently is an optionally substituted alkylene, cycloalkylene or arylene group.

In one embodiment, each E group independently is an optionally substituted C-i-30-alkylene group, especially an optionally substituted C1-20 alkylene group and most especially an optionally substituted C2-8 alkylene group. The alkylene groups may be branched or linear. Preferred examples include -(CH₂)i-2o- groups, examples of which are -(CH₂)₂-, -(CH₂)₃-, -(CH₂) -, -(CH₂)₆- and -(CH₂)₈-. In another embodiment, each E group independently is an optionally substituted arylene group, especially an optionally substituted phenylene group.

The E groups may be different to each other (for example some may be optionally substituted alkylene groups and others may be optionally substituted arylene groups) but are preferably they are all the same as each other.

The optionally substituents which may be present in each E group include - N0₂, CN, halo (especially CI, F, Br and I), -NHC(0)Ci_-6alkyl, -S0₂NHCi_-6alkyl, - S0₂Ci-6-alkyl, -C-i-6-alkyl, -OC-i-6-alkyl, -OC(0)Ci-6-alkyl, polypropyleneoxide ending in a C-i-6-alkyl group, polyethyleneoxide ending in a d-6-alkyl group. Preferably, the E groups are unsubstituted.

Each D group may independently be any of the groups mentioned above for A¹ and A². Preferably, the D groups are selected from optionally substituted alkylene, cycloalkylene and arylene groups. Preferably, each D group independently is an optionally substituted C-i-30-alkylene, phenylene, xylylene or naphthylene group, especially an optionally substituted C-i-30-alkylene group (more especially an optionally substituted C3-3o-alkylene group, which may be linear but are preferably branched. Preferably, at least some (more preferably all) of the D groups are optionally substituted C-i-30-alkylene groups.

The D group may be the residue of a polyetherdiamine residue for example that present in the Jeffamine™ products from Huntsman.

In general terms D optionally comprises polyalkeneoxy groups especially polyethyleneoxy and polypropyleneoxy groups including mixtures thereof.

So D may be, for example, -(CH₂)₂ to 3-OCH₂CH₂0-(CH₂)2 to 3-; or - (CH(CH₃)CH₂-0-)i to 7oCH₂CH(CH₃)-.

Particularly preferred D groups represented by D include 1 ,2-propylene, 2- and 3-methylhexamethylene, 3-isopropyl-hexamethylene, 2-tert-butyl- hexamethylene, 2,3-, 2,4-, 2,5-, 3,3- and 3,4-dimethylhexamethylene, 3-isooctyl- hexamethylene, 3-iso-dodecylhexamethylene, 2-methyl-4-ethylhexylmethylene, 2,2,4- and 2,4,4-trimethylhexamethylene, 2,2,5,5-tetramethylhexamethylene, 2,4- diethyl-octamethylene. Of these 2,2,4- and 2,4,4- trimethylhexamethylene and mixtures thereof have provided especially good dispersant properties. Preferably, at least some of the D groups are selected from this list, more preferably all the D groups present are selected from this list.

The optional substituents which may be present as part of D include -NO₂, CN, halo (especially CI, F, Br and I), -NHC(O)Ci_-6-alkyl, -SO₂NHCi_-6-alkyl, -SO₂Ci_ 6-alkyl, -C-i-6-alkyl, -OC-i-6-alkyl, -OC(O)Ci-6-alkyl, polypropyleneoxide ending in a C-i-6-alkyl group and polyethyleneoxide ending in a C-i-6-alkyl group. Preferably, D is unsubstituted. The preferences for each R⁵ and R⁶ group independently is as described above for the R¹ to R⁴ groups.

Preferably, each R⁵ and R⁶ group independently is selected from methyl, ethyl and H, more preferably all of the R⁵ and R⁶ groups are H.

When R⁵ and R⁶ join together so as to form a cyclic group they may do so along with D and the two nitrogen atom to which they are attached. For example, R⁵ and R⁶ preferably form a -CH₂CH₂- which bridges the two nitrogen atoms shown in Formula (2) and the group D optionally also is -CH₂CH₂-. Thus -NR⁵-D- NR⁶- is optionally of the formula:

When the process is performed using only one component ii), the resultant polymer comprises only one compound of Formula (2) with a single n value, n is an integer e.g. 1 , 2, 3, 4, 5... . etc. However when the process is performed using more than one component ii), the resultant polymer will contain units having different values of n.

Thus the value of n in the resultant polymer is not necessarily an integer, especially when the polymer is obtained from more than one component ii) each of which has a different value of n. For example the number averaged n value for the resultant polymer can be 1 .35, 7.56 or 20.76, etc. For conciseness m can be defined as the number averaged n value for all compounds of Formula (2) having different n values. The value of m must also be at least 1 .

The value of n (or if appropriate m) can be readily approximated by measuring or calculating the number averaged molecular weight of the compounds of Formula (2) used to prepare the polymer.

A preferred method for establishing n (or m) is proton NMR.

n (or m) is preferably no more than 10,000, more preferably less than 5,000, especially less than 1 ,000 and most especially less than 500.

Low molecular weight compounds of Formula (2) are often preferred in which case n (or m) is preferably no more than 100, more preferably no more than 20, even more preferably no more than 10, especially no more than 5 and most especially no more than 3.

In some cases, where higher molecular weights are desired, n (or m) is preferably more than 2, 3, 5 or 10.

Especially preferred compounds of Formula (2) are those wherein:

each T independently is a halogen (especially CI);

each E independently is a d-30-alkylene (especially -(CH₂)₄- or - (CH₂)₈-) or arylene (especially phenylene) group; each D independently is a branched C3-30 alkylene group; and each R⁵ and R⁶ independently is methyl, ethyl or, more preferably, H.

In one embodiment, the compound of Formula (2) contains no water- dispersing groups. In another embodiment, the compound of Formula (2) contains no water-dispersing groups other than the -CO2H present when T is OH.

The compounds of Formula (2) may be prepared by reacting a compound of the Formula T(C=O)E(C=O)T with a compound of the Formula HR⁵N-D-NR⁶H. The reaction is preferably performed in an aprotic solvent, a preferred example of which is N-methyl pyrrolidone. The reaction temperature is preferably from -30 to +30°C and especially from -10 to +10°C. The time for the reaction is typically from 1 minute to 2 hours, more preferably from 5 minutes to 1 hour.

The molecular weight of the compound of Formula (2) may be determined in part by the stoichiometry (i.e. from the relative molar amounts of the reactants). As the stoichiometry approaches a molar ratio of 1 : 1 , high molecular weight compounds of Formula (2) can be prepared with larger n values. It can be sometimes advantageous to use a slight molar excess of the component of Formula T(C=O)E(C=O)T (e.g. diacid or diacid chloride) to the compound of the Formula HR⁵N-D-NR⁶H (diamine) as this can be of assistance in providing the compound of the Formula (2) having the desired end groups. Preferably, the molar ratio of the compounds of the Formula T(C=O)E(C=O)T to those of the Formula HR⁵N-D-NR⁶H is from 5: 1 to 1 : 1 , more preferably from 2: 1 to 1 :1 and especially from 1 .5: 1 to 1 : 1 .

Preferred compounds of the formula T(C=O)E(C=O)T include dicarboxylic acids and diacid chlorides. Preferred examples are the d-30-aliphatic dicarboxylic acids and diacid chlorides especially adipic acid, sebacic acid, adipoyi chloride and sebacoyl chloride.

Preferred compounds of the Formula HR⁵N-D-NR⁶H include diamines, especially primary diamines. Preferred examples include branched and linear aliphatic diamines, especially C3-30 branched diamines. Preferred examples of compounds of the Formula HR⁵N-D-NR⁶H include 1 ,2-propylene diamine, 2- and 3-methylhexamethylene diamines, 3-isopropyl-hexamethylene diamine, 2-tert butyl-hexamethylene diamine, 2,3-, 2,4-, 2,5-, 3,3- and 3,4-dimethylhexamethylene diamine, 3-isooctyl-hexamethylene diamine, 3-iso-dodecylhexamethylene diamine, 2-methyl-4-ethylhexylmethyl diamine, 2,2,4- and 2,4,4-trimethylhexamethylene diamine and mixtures thereof, 2,2,5,5-tetramethylhexamethylene diamine and 2,4- diethyl-octamethylene diamine

Optionally the compounds of Formula (2) are purified before reaction with the compounds of Formula (1 ) The reaction between the compounds of Formula (1 ) and (2) is preferably performed in an aprotic solvent. A preferred aprotic solvent is N-methyl pyrrolidone. The reaction temperature is preferably in the range of from -30 to 100°C. It is preferred to increase the temperature of the reaction as it proceeds. For example, one may perform the early stages of the reaction at a temperature of from -10 to +10°C and then to slowly increase the temperature up to about 50°C and then up to about 80°C so as to complete the reaction.

The molecular weight of the resultant polymer is controlled to a large extent by the molar stoichiometric amounts of the compounds of Formula (1 ) and (2). When the molar stoichiometry approaches 1 : 1 , high molecular weight polymers are obtained. Preferably the stoichiometry is such that the molar ratio of the compounds of Formula (1 ) to the compounds of Formula (2) is from 0.33 to 1 to 3: 1 , more preferably from 0.5: 1 to 2: 1 , even more preferably from 0.75: 1 to 1 .5: 1 and especially from 0.8: 1 to 1.2: 1 .

In addition to the mandatory components i) and ii) the reaction may also comprise optional component iii).

Component iii) may comprise one or more diacid chlorides and/or diacids, preferably these are of the formula T(C=0)E(C=0)T wherein T and E are independently as hereinbefore defined. Here T and E need not be the same as they are in component ii).

Component iii) may further comprise one or more diamines, preferably these are of the Formula NHR⁵DR⁶NH wherein R⁵, R⁶ and D independently are as previously defined. Diamines containing pyrimidine and 1 ,3-dinitrobenzene can be used. Here R⁵, R⁶ and D need not be the same as they are in component ii).

Preferably, component iii) is present at no more than 30 parts, more preferably no more than 10 parts, especially no more than 5 parts and more especially 0 parts by weight, relative to 100 parts by weight of the sum of components i) and ii).

In a further embodiment, the process further comprises the further step iv), after step i), ii) and iii) (when performed), of reacting the product of the process wherein Z is halogen with an organic amine, thiol and/or alcohol.

Preferably, the organic amine, thiol and/or alcohol used in optional step iv) comprises least one water-dispersing group, for example one of the water- dispersing groups described above in relation to A¹ and A². Prefered organic amines, thiols and alcohols which may be used in step iv) are mono-amines, mono- alcohols and mono-thiols. The amine is preferably a primary amine or a secondary amine.

Preferably the organic amine, thiol and/or alcohol used in step iv) is a compound of the Formula (3) or (4): J-Y

Formula (3)

Y. Ύ

N

Formula (4) wherein:

J is H₂N- HO- or HS-; and

Y each Y independently is an optionally substituted organic group;

Preferably Y in Formula (3) and one or both of the groups represented by Y in Formula (4) comprise at least one water-dispersing group.

More preferably all of the organic amines, thiols and/or alcohols used in step iv) are of the Formula (3) or (4), as defined above.

In some instances it can be advantageous to use mixtures of organic amines, thiols and/or alcohols in step iv) wherein some have water-dispersing groups and others do not.

In the compounds of Formula (3) it is preferred that L is H₂N- or HO-, more preferably H₂N-. The optionally substituted organic group Y in the compounds of Formula (3) and (4) may be of any kind without limitation. Y may be, for example, an optionally substituted alkyl, aryl, heterocyclyl group or a combination of two or more of such groups.

When a Y group is an optionally substituted alkyl group, it is preferably optionally substituted C1-20 alkyl.

When a Y group is an optionally substituted aryl group it is preferably an optionally substituted phenyl or naphthyl group.

When a Y group is an optionally substituted heterocyclyl group it is preferably an aromatic (heteroaryl) or non-aromatic group. When Y is an optionally substituted heterocyclyl group it preferably comprises a 5- or 6- membered ring containing from 1 to 3 atoms selected from N, S and O in the ring and the remaining ring atoms are carbon atoms.

Preferred examples of optionally substituted heterocyclyl groups represented by Y include optionally substituted pyrrolyl, thiophenyl, furanyl, pyridyl, pyrimidyl, pyrazinyl, triazinyl, imidazolyl, thiazolyl, oxazolyl and pyrazolyl groups. The optional substituents may be any of those previously mentioned for A¹ and A² above.

Preferably at least some (preferably all) of the organic amine, thiol and/or alcohol compounds used in optional step iv) comprise one or more water-dispersing groups, especially ionic groups, e.g. any of the water-dispersing and ionic groups described above in relation to A¹ and A².

Preferred examples of compounds of Formula (3) and (4) include aminomethylphosphonic acid, iminodi(methylphosphonic acid), N- methylaminomethylphosphonic acid, 2-aminoethylphosphonic acid, 3- aminopropylphosphonic acid, meta-, ortho- and para-aminophenylphosphonic acid, 4-aminobenzyl phosphonic acid, alendronic acid, pamidronic acid, neridronic acid, glyphosate, 2-amino-3-phospono propionic acid, 2-amino-4-phosophono butyric acid and the like. Of these, aminomethylphosphonic acid and alendronic acid are preferred.

According to a second aspect of the present invention there is provided the polymer obtained or obtainable by the process according to the first aspect of the present invention.

Of course the preferred polymers of the second aspect of the present invention are obtained or obtainable by reacting the preferred process(es) as mentioned above, e.g. using the preferred compounds of Formula (1 ) and (2).

Preferred polymers have an acid value of no less than 0.1 mmoles/g, more preferably no less than 0.25mmoles/g, especially no less than 0.5mmoles/g and most especially no less than 0.75mmoles/g.

Preferred polymers have an acid value of not more than 4mmoles/g, more preferably not less than 3mmoles/g, even more preferably not more than

2mmoles/g and especially not more than 1 .5mmoles/g.

Preferably, the polymer has the abovementioned acid values from groups selected from carboxylic acid, sulfonic acid and especially phosphorus containing acids, more preferably from carboxylic acids and phosphorus containing acids and especially from phosphorus containing acids (from which phosphonic acid is preferred). The acid value may be measured by titration.

Preferably, the polymer has one or more acid groups selected from sulfonic acid, carboxylic acid and phosphorus containing acid groups (especially phosphonic acid groups). Preferably the polymer has acid groups selected from the group consisting of carboxylic acids and phosphonic acids, more preferably from the group consisting of phosphonic acids. In other words, the polymer is preferably free from acid groups other than those explicitly mentioned above. Preferably some (more preferably all) of the acidic groups present in the polymer are obtained from the Z group in the compound of Formula (1 ) or from the Y group(s) in the compound(s) of Formula (3) and (4).

The polymer obtained from the process may be used with or without having been purified. Preferably, however, the process further comprises the step of purifying the polymer, for example to remove some or substantially all impurities, e.g. unpolymerised compounds, any protecting group residues and any post functionalising residues. Suitable methods for purification include acid precipitation, washing and re-dissolving and membrane washing the polymer (especially ultrafiltration).

The weight average molecular weight (Mw) of the polymer is preferably not less than 1 ,000, more preferably not less than 5,000 and especially not less than 10,000. The Mw is preferably no more than 1 ,000,000, more preferably no more than 500,000, even more preferably no more than 200,000 and especially no more than 100,000. The Mw is preferably established by gel permeation chromatography (GPC). This is preferably performed using polystyrene standards of known molecular weights. The preferred solvent for the GPC is a mixture of dimethyl formamide, acetic acid and triethylamine. The number averaged molecular weight (Mn) can also be established by the above GPC method.

The polymer may be water-insoluble or partially soluble but is more preferably water-soluble, e.g. preferably having a water-solubility of at least 10g, more preferably at least 12g, especially at least 15g and more especially 20g of polymer per 100g of water. To determine the solubility in water, any ionic groups present in the polymer are preferably neutralised with KOH or HCI (as appropriate) to 100%. The solubility is preferably measured at 25°C.

Preferably, the polymer has a phosphorus content of from 0.05 to 20wt%, more preferably from 0.5 to 20wt%, even more preferably from 0.5 to 10wt%, especially from 0.5 to 5wt% and more especially from 0.5 to 4wt%.

In order of increasing preference, the polymer preferably has a phosphorus content of at least 0.05wt%, 0.1 wt%, 0.25wt%, 0.5wt% and 1wt%.

In order of increasing preference, the polymer preferably has a phosphorus content of no more than 20wt%, 10wt%, 7wt%, 5wt%, 4wt% and 3wt%.

The phosphorus content of the polymer may be established by elemental analysis, e.g. using inductively coupled plasma - optical emission spectrometer (ICP-OES). A preferred ICP-OES device for determining the phosphorus content is a Perkin Elmer 3300DV.

According to a third aspect of the present invention there is provided a dispersion comprising a polymer according to the second aspect of the present invention, a particulate solid and a liquid vehicle. The particulate solid preferably has a volume average (Mv) particle size of from 50 to 300nm, more preferably from 70 to 200nm and especially from 80 to 150nm. The particle size is preferably measured by a light scattering device, especially a Nanotrac 150 device.

Preferably, the dispersion comprises:

i) 0.1 to 40 parts, more preferably 0.1 to 20 parts of the polymer according to the second aspect of the present invention;

ii) 0.1 to 40 parts, more preferably 0.1 to 20 parts of the particulate solid;

iii) 50 to 99.8, more preferably 60 to 99.8 parts of the liquid vehicle;

wherein the sum of the parts i) to iii) is 100 parts and all parts are by weight.

In some cases at least some of the polymer is adsorbed, affixed or bonded onto the surface of the particulate solid and acts so as to colloidally stabilize the particulate solid in the liquid medium.

Preferably, the polymer is at least partially adsorbed onto the surface of the particulate solid. In this way the polymer acts as a dispersant so as to colloidally stabilise the particulate solid in the liquid medium.

In other cases the polymer is substantially separate from the particulate solid. In this case the polymer is not acting so as to disperse the particulate solid. Instead, the polymer is acting as, for example, a binder.

The amount of polymer in the dispersion (or ink) is preferably from 1 to

150%, more preferably from 1 to 50%, especially from 1 to 40% and more especially from 10 to 40% by weight, relative to the weight of particulate solid.

A preferred method for preparing the dispersions according to the third aspect of the present invention is to disperse, especially to comminute, a composition comprising the polymer according to the second aspect of the present invention, a particulate solid and a liquid vehicle. Dispersion processes include stirring, blending, shaking as well as milling and ultrasonication, etc.

The preferred comminution processes significantly reduce the particle size of the particulate solid. Comminution includes, for example, ultrasonication, bead milling, microfluidizing and high pressure homogenising and a combination of two or more thereof. Comminution does not include low shear dispersion processes such as stirring, shaking, tumbling and the like, although these may be used prior to comminution to form a pre-dispersion. Preferably, the polymer according to the second aspect of the present invention is the only dispersant present during the dispersion or comminution step.

The particulate solid may be of any kind. Preferably the particulate solid is a pigment. The pigment may comprise and preferably is an inorganic or organic pigment material or mixture thereof which is insoluble in the liquid vehicle. By insoluble we mean having a solubility of no more than 1 %, more preferably no more than 0.1 %, by weight in the liquid vehicle. The solubility is preferably measured at a temperature of 25°C. The solubility is preferably measured at a pH of 8.

Preferably, the pigment has a solubility in deionized water at 25^°C of no more than 1 wt%, more preferably no more than 0.1 wt%.

Preferred pigments include, for example, any of the pigments described in the Third Edition of the Colour Index (1971 ), including subsequent revisions of, and supplements thereto, under the chapter headed "Pigments". Examples of organic pigments include those from the azo (including disazo and condensed azo), thioindigo, indanthrone, isoindanthrone, anthanthrone, anthraquinone, isodibenzanthrone, triphendioxazine, quinacridone and phthalocyanine series, especially copper phthalocyanine and its nuclear halogenated derivatives, and also lakes of acid, basic and mordant dyes. Preferred organic pigments are phthalocyanines, especially copper phthalocyanine pigments, azo pigments, indanthrones, anthanthrones, and quinacridones.

Preferred inorganic pigments include carbon black (especially gas blacks), titanium dioxide, silicon dioxide, aluminium oxide, iron oxides and sulfides.

For ink jet printing, especially suitable pigments are carbon blacks, C. I. Pigment Red 122, C.I. Pigment Blue 15:3 and C.I. Pigment Yellow 74. Of course there are many alternative pigments.

The pigment is preferably not surface treated so as to covalently bind water- dispersing groups onto its surface. Preferably, the pigment is not dispersible in water without the aid of a dispersant.

The liquid vehicle may be wholly organic, although preferably the liquid vehicle is or comprises water (i.e. it is aqueous). We have found that the polymer according to the second aspect of the present invention is especially suitable for dispersing particulate solids in aqueous liquid vehicles.

In some cases, the liquid vehicle comprises water and optionally one or more water-miscible organic liquids. Preferably, the liquid vehicle comprises water and optionally from 1 to 3, water-miscible organic liquids.

Preferred water-miscible organic liquids for inclusion into the liquid vehicle include:

i) C-i-6-alkanols, preferably methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, tert-butanol, n-pentanol, cyclopentanol and cyclohexanol;

ii) linear amides, preferably dimethylformamide or dimethylacetamide;

iii) water-miscible ethers, preferably tetrahydrofuran and dioxane;

iv) diols, preferably diols having from 2 to 12 carbon atoms, for example ethylene glycol, propylene glycol, butylene glycol, pentylene glycol, hexylene glycol and thiodiglycol and oligo- and poly-alkyleneglycols, preferably diethylene glycol, triethylene glycol, polyethylene glycol, dipropylene glycol and polypropylene glycol;

v) triols, preferably glycerol and 1 ,2,6-hexanetriol;

vi) mono-C-i-4-alkyl ethers of diols, preferably mono-Ci-₄-alkyl ethers of diols having 2 to 12 carbon atoms, especially 2-methoxyethanol, 2-(2- methoxyethoxy)ethanol, 2-(2-ethoxyethoxy)-ethanol, 2-[2-(2-methoxyethoxy) ethoxy]ethanol, 2-[2-(2-ethoxyethoxy)-ethoxy]-ethanol and ethyleneglycol monoallylether;

vii) cyclic amides, preferably 2-pyrrolidone, N-methyl-2-pyrrolidone, N-ethyl-2- pyrrolidone, caprolactam and 1 ,3-dimethylimidazolidone.

Preferred water-miscible organic liquids to aid the dispersion or comminution step are the diols of category iv), especially dipropylene glycol. One advantage of the polymers prepared using the process according to the first aspect of the present invention is that they may be used to disperse or comminute particulate solids in liquid vehicles without requiring large amounts of water-miscible organic liquids.

According to a fourth aspect of the present invention there is provided a a process for preparing a dispersion according to the third aspect of the present invention which comprises dispersing a particulate solid in a composition comprising a liquid vehicle and a polymer according to the second aspect of the present invention, wherein the liquid vehicle comprises water and a water-miscible organic liquid, wherein the water-miscible organic liquid is present in an amount of less than 30% by weight, more preferably less than 20% by weight and especially less than 10% by weight, relative to the total amount of liquids present in the composition.

In one embodiment of the fourth aspect of the present invention, the liquid vehicle comprise water and is free from water-miscible organic liquids.

The dispersions according to the third aspect of the present invention can be used to prepare encapsulated particulate solids. To form an encapsulated particulate solid, the polymer in the dispersion may be cross-linked in the presence of a particulate solid and a liquid vehicle, thereby encapsulating the solid particles within a cross-linked polymer shell.

The particulate solid is preferably a pigment as mentioned and preferred above. The liquid vehicle is preferably as mentioned above.

The cross-linking optionally comprises the formation of ionic or hydrogen bonds, but preferably the cross-linking comprises the formation of covalent bonds.

The cross-linking can be achieved by using a self cross-linking polymer. More preferably, however, a cross-linking agent is used to cross-link the polymer around the particulate solid. Typically the cross-linking agent comprises cross- linking groups which are reactive with cross-linkable groups present in the polymer. Examples of suitable combinations of cross-linkable groups in the polymer and cross-linking groups in the cross-linking agent are listed in WO 2005/061087 at page 6, Table 1 . Of these it is preferred that the cross-linkable group in the polymer is an ionic group, especially a carboxy (e.g. -CO2H) group and/or a phosphorus containing acid group, or salt thereof. For these cross- linkable groups the cross-linking agent is preferably selected from melamines, carbodiimides, oxetanes, isocyanates, aziridines and especially epoxides. Preferably, cross-linking is effected by means of an epoxy cross-linking agent, i.e. a cross-linking agent comprising two or more epoxy groups.

Especially suitable encapsulation and cross-linking chemistries can be found in PCT patent publication WO 2006/064193.

It will be appreciated that encapsulated particulate solids are discrete particles, each comprising a particulate solid core and an encapsulating polymeric shell. Dispersions of encapsulated particulate solids in liquid vehicles are fluid.

According to a fifth aspect of the present invention there is provided an ink comprising a dispersion according to the third aspect of the present invention.

In inks, the particulate solid is a colorant, e.g. a dye or preferably a pigment. The liquid vehicle

Preferably the ink is an ink jet printing ink.

Preferably the ink has a viscosity of less than 30mPa.s, more preferably less than 20mPa.s and especially less than l OmPa.s. The viscosity is preferably at least 2mPa.s. Preferably, the viscosity is Newtonian. Preferably the viscosity is measured at 25°C. Preferably, the viscosity is measured using a shear rate of 100s^"1. The viscosity is preferably measured using a cone and plate geometry. A preferred apparatus for measuring the viscosity is a TA Instruments rheometer.

Preferably the ink according to a fifth aspect of the present invention comprises:

i) 0.1 to 10 parts, more preferably from 1 to 10 parts, of the polymer according to the second aspect of the present invention;

ii) 0.1 to 10 parts, more preferably from 1 to 10 parts, of a pigment;

iii) 80 to 99.8 parts, more preferably 80 to 98 parts, of a liquid vehicle

wherein all parts are by weight.

The polymer may be, for example, separate from the pigment or it may be adsorbed onto the pigment. The polymer and pigment may be in the form of encapsulated particles as mentioned above.

The ratio of polymer to pigment is as hereinbefore preferred. Preferably the ink has a surface tension of 20 to 65 dynes/cm, more preferably 30 to 60 dynes/cm, when measured at a temperature of 25°C. The surface tension is preferably measured using a Kibron AquaPi device.

The pH of the ink is preferably from 4 to 1 1 , more preferably from 7 to 10. When the ink is to be used as ink jet printing ink, the ink preferably has a concentration of halide ions of less than 500 parts per million, more preferably less than 100 parts per million. It is especially preferred that the ink has a concentration of less than 100 parts per million, more preferably less than 50 parts per million, of divalent and trivalent metals. Parts per million as used above refers to parts by weight relative to the total weight of the ink. These low concentrations of ions in the resultant ink can be achieved by the abovementioned purification techniques.

Preferably the ink is substantially free from particles having a particle size (e.g. diameter) of greater than 1 micron. The ink may be treated to remove such particles by, for example, centrifugation or filtration.

The ink preferably comprises a liquid vehicle which is or comprises water. More preferably the liquid vehicle further comprises at least one water-miscible organic liquid. Preferably, the weight ratio of water to water-miscible organic liquid when both are present in the liquid vehicle is from 99:1 to 5:95, more preferably 95:5 to 50:50, especially 95:5 to 70:30. Suitable water-miscible organic liquids are mentioned above, although the preferences for particular water-miscible organic liquids tends to be affected by inter alia the printer design and the choice of substrate.

The inks of the present invention are especially useful for ink jet printing because they have a low tendency to suffer from polymer depositing on the ink jet printer nozzles in what is sometimes called a "seeping out" phenomina. The water- miscible organic liquids also help in the firing, substrate wetting, surface tension and substrate penetration characteristics of the ink.

The inks may optionally contain one of more further ink additives, e.g. viscosity modifiers, pH buffers, metal chelating agents, surfactants, corrosion inhibitors, biocides, dyes and/or kogation reducing additives.

According to a sixth aspect of the present invention there is provided an ink jet printer cartridge comprising a chamber and an ink, wherein the ink is present in the chamber and the ink is as defined in the fifth aspect of the present invention.

According to a seventh aspect of the present invention there is provided a substrate printed with an ink according to the fifth aspect of the present invention.

The substrate may be of any kind, including paper, glass, metal, material and plastic. We have found that the inks according to the fifth aspect of the present invention provide prints having especially good optical density, even on plain paper. The prints also demonstrate particularly good wet and dry rub- fastness.

Inks of the present invention may also be used with substrates which contain fixatives.

According to an eighth aspect of the present invention there is provided the use of a polymer according to the second aspect of the present invention for dispersing (especially comminuting as mentioned above) a particulate solid in a liquid vehicle.

The preferred particle size of the particulate solid and the preferred liquid vehicles are as mentioned and preferred above.

Experimental

The present invention will now be illustrated by the following examples in which all parts are by weight unless stated to the contrary.

1 . Preparation of Dispersant Aqueous solutions (1 ) to (5)

1 .1 Preparation of Diamine 1 ) (a compound of Formula (1 ))

Diamine (1 )

1 .1 .1 A suspension of cyanuric chloride (20g, 108mmol) in water (300ml_) and calsolene oil (3 drops) was stirred for 30 minutes at just under 5°C. The pH of the suspension was raised to 6.5 (using saturated aqueous K2CO3) and the temperature was maintained at 5°C. A solution of aminomethanephosphonic acid (1 1 .7g, 103 mmol) was added to the suspension to form a reaction mixture. This reaction mixture was stirred at a temperature just below 5°C for 4 hours with the pH being maintained in the range 6.5-7. The mixture was cooled to 20°C. The resulting mixture was filtered (using a Whatman No 1 filter) and the filtrate was retained.

1 .1 .2 4-Aminoacetanilide (17g, 133 mmol) was added portionwise as a solid to the filtrate prepared in step 1 .1 .1 at a temperature just below 5°C and the mixture was stirred overnight. The mixture was heated to a temperature of 40°C for a period of 2 hours. The mixture was filtered to remove insoluble material. Further 4-Aminoacetanilide (17g) was subsequently added portionwise and the mixture was stirred and heated to a temperature of 80°C for a period of 4 hours with the pH being maintained at 9.5 (using saturated aqueous K2CO3). The mixture was allowed to cool down to 20°C and the pH was lowered to 2. This precipitated a solid. The solid, protected diamine was filtered off and dried and had the following structure:

1 .1 .3 The solid, protected diamine obtained in step 1 .1 .2 was dissolved in 10% aqueous KOH (500g) and the solution was stirred and heated to 95°C for a period of 4 hours and allowed to cool to 20°C. The solution was filtered and the pH was lowered to 4.5 (using HCI). The solid which precipitated was filtered off and redissolved in water (600ml_) at pH 1 . The product was salted out from the solution (using KCI, 12% wt in water), filtered-off and redissolved in water (100ml_) at pH 8 to form a solution. The pH of the solution was lowered to 4.8 and the solid was filtered-off and washed with water. This resulted in a wet sample of the compound of Diamine (1 ) which was dried at 80°C.

1 .2 Preparation of Pi Acid Chloride (1 ) (a compound of Formula (2))

A solution of a mixture of 2,2,4 and 2,4,4- trimethylhexamethylenediamine (1 .04g, 6.6mmol) and diisopropylethylamine (DIPEA, 1 .7g, 13.2mmol) in NMP (25m L) was added dropwise over 30 minutes to a cooled (<0°C, salt/ice), rapidly stirred solution of adipoyl chloride (2.42g, 13.2mmol) in NMP (50ml_). The mixture was stirred for 30 minutes. This formed a solution of what is called Di Acid Chloride (1 ).

Di Acid Chloride (1 )

1 .3 Preparation of Polvamide Dispersant (2)

1 .3.1 Diamine (1 ) as prepared in 1 .1 (3.42g, 6.6mmol) was dissolved in N-methyl pyrollidone (NMP) (100ml_) and diisopropylethylamine (DIPEA, 3.4g, 26.4mmol) by stirring and heating to a temperature of 80°C for 1 hour. The resultant solution was allowed to cool down to 20°C.

1 .3.2 The solution prepared in step 1 .3.1 was added dropwise to the solution of Di Acid Chloride (1 ) obtained in step 1 .2. The cooling bath was removed and the mixture was allowed to warm up to 20°C over 1 hour, the mixture was then heated to 50°C for 30 minutes and then to 80°C for 1 hour. The mixture was allowed to cool down to 20°C and was poured into ice/water (400m L). The pH was lowered to 1 .5 (using HCI) and the precipitated solid was filtered-off.

1 .3.3 The solid formed in step 1 .3.2 was redissolved in water (200ml_) at pH 12 (KOH) to form a solution. The solution was filtered (using a Whatman No 1 filter). The pH of the solution was lowered to 1 .5 (using HCI) and the precipitated solid was filtered-off. The solid was redissolved in water (pH 10) and the solution was dialysed with deionized water until the conductivity was less than 100 S cm^-'' . The solution was concentrated using a rotary evaporator to give an aqueous solution having a total solids content of approximately 15wt%. This resulted in an aqueous solution containing Dispersant (1 ) having the Formula (5) wherein n = 1 , which was subsequently called Dispersant Aqueous Solution (1 ):

Formula (5)

1 .4 Preparation of Dispersant Aqueous Solutions (2) - (5)

Dispersant aqueous solutions (2) to (6) were prepared in exactly the same way as Dispersant Aqueous Solution (1 ) except that in each case the molar ratio of adipoyl chloride to the mixture of 2,2,4 and 2,4,4- trimethylhexamethylenediamine was changed in order to alter the value of n in Formula 5. Table 1

The proton NMR spectra for the Dispersants in Dispersant Aqueous Solutions (1 ) to (5) were recorded. The proton spectra were consistent with the n values indicated in Table 1 above.

2. Preparation of Dispersant Aqueous Solution (6)

2.1 Preparation of a Solution of Diamine (1 )

Diamine (1 ) from Step 1 .1 (4.5g, 10.6 mmol) was dissolved in a mixture of NMP (35 mL) and Ν, Ν-Diisopropylethylamine (DIPEA) (5.5g, 42.4 mmol) by stirring at room temperature for 15 minutes and then at 45°C for 15 minutes.

2.2 Preparation of Di Acid Chloride (2)

Di Acid Chloride (2)

NMP (40 mL) was stirred and cooled (salt/ice, -2°C). Adipoyi chloride (7.77g, 42.5 mmol) was added to the cold NMP with stirring. A cooled (ice bath) solution of 5-amino-1 ,3,3-trimethylcyclohexanemethylamine (mixture of cis and trans) (5.4g, 31 .8 mmol) and DIPEA (8.2g, 63.6 mmol) in NMP (30 mL) was added dropwise to the cold solution of adipoyi chloride at such a rate that the temperature remained <0°C. The addition was completed after 20 minutes. The resultant, slightly cloudy mixture was stirred for 5 minutes at <0°C to give Di Acid Chloride (2). 2.3 Reaction of Diamine (1 ) and Pi Acid Chloride (2)

The solution of Diamine (1 ) prepared in step 2.1 was cooled in an ice bath and then added dropwise to the Di Acid Chloride (2) prepared in step 2.1 . The reaction mixture became very thick and a further portion of NMP (50 ml_) was added. The mixture was stirred for and additional 15 minutes and then the cooling bath was removed. The mixture was allowed to warm up to room temperature over 30 minutes and the mixture was then stirred and heated at 80°C for 1 hour.

The mixture was allowed to cool down to room temperature and was poured into ice/water (300 ml_). The pH was lowered to 1 .5 using concentrated hydrochloric acid solution and the resultant, precipitated solid was filtered-off.

The solid was re-disssolved in water (200 ml_) at pH 12 (KOH) and the solution was filtered (Whatman No 1 ) to remove unwanted solids. The solution was dialysed to remove salts until it had a conductivity below 100 μβοητ¹. The volume of the solution was reduced on rotary evaporator to give Dispersant Aqueous Solution (6) having a solids content 22.5 wt%, which contained Dispersant (6) of Formula (6):

Formula (6) 3. Millbase Preparation

3.1 Black Millbase (1 )

Black millbase (1 ) was prepared by mixing pigment powder (3 parts of NIPex^R™ 170IQ Carbon Black pigment, ex Evonik Degussa), Dispersant Aqueous Solution (1 ) (2 parts) and water (15 parts) to form a premixture.

The premixture was then treated with ultrasound (using a Branson Digital

Sonifier operating at 60% amplitude) at 5°C for 1 5 minutes. This resulted in Black Millbase (1 ). The pigment particles in the resulting millbase had an Mv particle size of 1 16 nm as measured by a Nanotrac 150. The proportion of pigment in Black Millbase (1 ) was approximately 15% by weight.

3.3 Black Millbases (2) - (18)

Black Millbases (2) to (18) were prepared using the same method as Black Millbase (1 ) except that the Dispersant Aqueous Solution and the wt% of polymer on pigment were as indicated in Table 2. Table 2

4. Preparation of Inks

Each of the Black Millbases prepared in Table 2 were used to prepare Ink having the following composition.

Ink Vehicle

^*Millbase suffient to provide 6 parts of pigment

2-Pyrrolidone 3.00 parts

Glycerol 15.00 parts

1 ,2 Hexane diol 4.00 parts

Ethylene glycol 5.00 parts

Surfynol™ 465 0.50 parts

Pure water sufficient to make 100 parts (Surfynol 465 is a surfactant available from Air Products).

^*6 parts of black pigment on an active or solids basis were used in all cases (approximately 40 parts of Black Millbase when the solids content is 15% by weight).

In terms of references Black Millbase (1 ) was used to prepare Black Ink (1 ) etc.

5. Preparation of prints

Each of the Inks described above in point 4 were printed onto plain

(untreated) paper, namely Xerox 4200 and Canon GF500 paper. Printing was performed by means of an SEC SX100 ink jet printer printing 100% blocks of black. 6. Measurement of Optical Density

For each print the reflectance optical density (ROD) was measured using a Gretag Macbeth key wizard V2.5 Spectrolino photodensitometer instrument, illuminated using a D65 light source at an observer angle of 2° and with no filter fitted. Measurements were taken at at least two points along the print and were then averaged.

7. Results of Optical Density Measurements

The results of the ROD measurements were as summarised below in Table

3.

Table 3 : ROD of Prints obtained from Black Inks (1 ) to (18)

Dispersant Wt% Polymer on ROD on ROD on

Ink Aqueous pigment Xerox 4200 Canon GF500

Solution Paper Paper

Black Ink (1 ) 1 10 1 .36 1 .38

Black Ink (2) 1 20 1 .30 1 .29

Black Ink (3) 2 10 1 .34 1 .35

Black Ink (4) 2 20 1 .34 1 .32

Black Ink (5) 3 10 1 .32 1 .35

Black Ink (6) 3 20 1 .37 1 .33

Black Ink (7) 3 30 1 .37 1 .35

Black Ink (8) 3 40 1 .28 1 .25 Black Ink (9) 4 10 1 .37 1 .38

Black Ink (10) 4 20 1 .35 1 .33

Black Ink (1 1 ) 4 30 1 .33 1 .30

Black Ink (12) 4 40 1 .35 1 .29

Black Ink (13) 5 20 1 .34 1 .33

Black Ink (14) 5 30 1 .35 1 .33

Black Ink (15) 5 40 1 .33 1 .31

Black Ink (16) 6 10 1 .32 1 .33

Black Ink (17) 6 20 1 .34 1 .31

Black Ink (18) 6 30 1 .37 1 .34

The polymers prepared by the process according to the first aspect of the present invention were excellent dispersants for pigments. Inks containing these polymers provided prints having excellent optical density, even on plain paper, as can be seen from the results in Table 3 above.

8. Further inks

The further inks described in Tables 4 and 5 may be prepared wherein each of the Black Mill-bases 1 to 18 (abbreviated to "BM" in Tables 4 and 5) is as mentioned above and the ink additives are as defined below. Numbers quoted in the second column onwards refer to the number of parts of the relevant ingredient and all parts are by weight. The inks may be applied to paper by thermal, piezo or Memjet ink jet printing.

The following abbreviations are used in Tables 4 and 5:

PG = propylene glycol

DEG = diethylene glycol

NMP = N-methyl pyrrolidone

DMK = dimethylketone

IPA = isopropanol

MEOH = methanol

2P = 2-pyrrolidone

MIBK = methylisobutyl ketone

P12 = propane-1 ,2-diol

BDL = butane-2,3-diol

Surf = Surfynol™ 465 from Air Products

PHO = Na₂HP0₄ and

TBT = tertiary butanol

TDG = thiodiglycol

GLY = Glycerol nBDPG = mono-n-butyl ether of dipropylene glycol nBDEG = mono-n-butyl ether of diethylene glycol nBTEG = mono-n-butyl ether of triethylene glycol BM = Black Millbase

CD 00 CD cn CO

cn CO o BM

cn cn cn cn cn cn CO CO

o o o o o o O o o o o o o o o o o o o o o o Mill-base

Content

o o Water

cn CO cn cn CO cn

PG

cn CD cn cn 00 cn

o o cn DEG

CO CD CO cn CD

NMP

cn CD cn CO CO CO

o o DMK > CD

I

m o o o

CO cn k> NaOH

o o o

CO cn k> Na Stearate

CO cn cn CD CD

IPA

CD cn

o MEOH

cn CO cn CD cn CD cn

cn 2P

CO CD cn cn cn

MIBK o GLY o nBDPG

Cn

> CD I

m cn

Claims

1 . A process for preparing a polymer comprising reacting at least the compounds in components i) and ii):

i) a compound of the Formula (1 );

Formula (1 )

wherein:

R¹ to R⁴ are each independently H or an optionally substituted alkyl, aryl or heterocyclyl group

A¹ and A² each independently are an optionally substituted divalent organic linking group;

Z is a halogen, -OH, -S-L, -O-L, a nitrogen-containing heterocyclic group, -NH₂, -NHL, or -NL₂, wherein each L independently is an optionally substituted alkyl, aryl or heterocyclyl group;

ii) a compound of the Formula (2):

Formula (2) each T independently is a halogen or an OH group;

each D and E independently is optionally substituted divalent organic linking group;

each R⁵ and R¹ independently is H or an optionally substituted alkyl, aryl, heterocyclyl group or R⁵ and R⁶ join together so as to form a cyclic group; and n is at least 1

2. A process according to claim 1 wherein the polymer has one or more acid groups selected from sulfonic acid, carboxylic acid and phosphorus-containing acids.

3. A process according to any one of the preceding claims wherein each D group independently is an optionally substituted d-30-alkylene, phenylene, xylylene or naphthylene group.

4. A process according to claim 3 wherein at least some of the D groups are branched C3-3o-alkylene groups.

5. A process according to claim 4 wherein at least some of the D groups are selected from 1 ,2-propylene, 2-and 3-methylhexametlhylene, 3-isopropyl- hexamethylene, 2-tert-butyl-hexamethylene, 2,3-, 2,4-, 2,5-, 3,3- and 3,4- dimethylhexamethylene, 3-isooctyl-hexamethylene, 3-iso-dodecylhexamethylene, 2-methyl-4-ethylhexylmetliyl, 2,2,4- and 2,4,4-trimethylhexamethylene, 2,2,5,5- tetramethylhexamethylene and 2,4-diethyl-octamethylene.

6. A process according to any one of the preceding claims wherein each E group independently is an optionally substituted Ci-3o alkylene group.

7. A process according to claim 6 wherein each E group independently is an - (CH₂)₂-, - (CH₂)₃-, - (CH₂)4- -(CH₂)₆- or - (CH₂)₈- group.

8. A process according to any one of the preceding claims wherein the polymer has acid value of from 0.5 to 2 mmoles/g.

9. A process according to any one of the preceding claims where Z is of the Formula -NHL, or -NL₂ and at least some of the L groups present carry one or more water-dispersing groups.

10. A process according to any one of the preceding claims wherein the polymer is water-soluble.

1 1 . A process according to any one of the preceding claims wherein n is from 1 to 20.

12. A process according to any one of the preceding claims where the polymer has a weight averaged molecular weight of from 1 ,000 to 100,000 g per mole.

13. A polymer obtained or obtainable by a process according to any one of the preceding claims.

14. A dispersion comprising a particulate solid, a liquid vehicle and a polymer according to claim 13.

15. A dispersion according to claim 14 wherein at least some of the polymer is adsorbed, affixed or bonded onto the surface of the particulate solid and acts so as to colloidally stabilize the particulate solid in the liquid medium.

16. An ink comprising a dispersion according to claim 14 or 15 wherein the particulate solid is a pigment.

17. An ink jet printer cartridge comprising a chamber and an ink, wherein the ink is present in said chamber and said ink is as defined in claim 16.

18. Use of a polymer according to claim 13 for dispersing a particulate solid in a liquid vehicle.