DISPERSANTS FROM LINEAR POLYURETHANES

FIELD OF INVENTION

[0001] The present invention relates to polyurethane dispersants and to dispersions, miJlbases, paints and inks containing particulate solid dispersed using said polyurethane dispersant in a non-aqueous organic medium, In particular, the polyurethane dispersant comprises an essentially linear anchoring portion having laterally attached tertiary amine groups (optionally quaterni/ed) and terminally attached solvent-solubilising polyester, polyether, and/or polyacrylate chains.

BACKGROUND OF THE INVENTION

[0002 J WO 2004/104064 discloses polyurethane dispersants of comb micrøstructure having an essentially linear backbone with laterally attached solvent-solubilising side chains of polyester, polyacrylic, polyether or polyolefϊn including mixtures of such side chains. A subsequent application WO 2008/070601 corresponding to PCT US07/086233 filed 03 December 2007 and published about June 12, 2008 teaches the corresponding comb microstructure polymers with tertiary and/or quaternized amine groups.

SIiMMARY OF THE INVENTION

[0003] According to the invention, there is provided a non-aqueous composition comprising a particulate solid, an organic medium and a polyurethane dispersant having one or more essentially linear anchoring backbone segmcnt(s) derived from difunctional urethane forming reactants with terminally attached solvent-solubilising terminal chains of polyester, polyether, and/or polyacrylate including mixtures of such terminal chains, and laterally attached groυp(s) with tertiary and/or quaternized tertiary amine on said anchoring backbone segment. In one embodiment, the nitrogen atom of the tertiary amine is desirable separated from the anchoring backbone by 1 to 20 intervening atoms. In one embodiment, the essentially linear anchoring backbone segment is formed by- reaction diisocyanates with a compound having two groups reactive with isocyanate and a tertiary and/or quaternized amine group. In one embodiment, from about 50 to about 95 mole percent of all the isocyanate groups of said diisocyanates used to make the

esscntially linear anchoring backbone segment are reacted with said compound with two groups reactive with isocyanatc groups and having a tertiary and/or quaternized tertiary amine group. The tertiary amine groups (optionally quaternized) have been found to be particularly active in anchoring the dispersant to some difficult to colloidally stabilize particulate materials. In one embodiment, significant portions of the tertiary amine groups are quaternized. The polyurelhane dispersant is also described and claimed separate from the non-aqueous composition, A process for making the dispersant from named compound groups is also presented.

DETAILED DESCRIPTION QF THE INVENTION

[0004] According to the invention, there is provided a non-aqueous composition comprising a particulate solid, an organic medium and a polyurethane (PU) dispersant having an essentially linear anchoring backbone structure with terminally attached solvent-solubilising chains (approximately two on average being preferred) of a polyester, polyether or polyacrylic including mixtures of such chains. The polyurelhane dispersant also comprises tertiary aliphatic amine moieties where the amine nitrogen is remote from the anchoring backbone with a spacer of at least 1 atom between the nitrogen and the backbone atom(s). The tertiary amine moiety is optionally quaternized. The optimum choice of the solvent-solubilising side chain for a particular organic solvent medium will be dependent on the polarity of the organic medium. The choice of organic medium will depend on the preferred organic medium in which the particulate is to be dispersed.

[00051 The polyurethane dispersants may be prepared by any method known to the art and arc obtainable or obtained by reacting together: a) one or more diisocyanates having an average functionality of from about 2.0 to 2.5, in another embodiment from about 2.0 to about 2.1 or 2,2, and in a third embodiment about 2.0 :

b) one or more compounds having a tertiary amino group of formula,

including salts thereof, R ^σ and R ^p are each independently alkyl. aralkyl, cycloalkyl or aryl and do not contain groups which can react with isoeyanates. R ⁷ is a moiety that contains two groups which react with isoeyanates. In one embodiment. It is preferred that R ^γ contains from about 1.9 or 2.0 to 2.5, in another embodiment about 1.9 or 2 to 2.1 or 2.2 groups that react with isoeyanates. It is especially preferred that R ^Y contains about/at least/ or in another embodiment about 2.0 groups that react with isoeyanates.

c) optionally, one or more urethane formative compounds having a number average molecular weight of from 32 to less than 500 Dalton which have two groups which react with isoeyanates;

d) one or more solvent-solubilising polyester, polyether or polyacrylate chain comprising one group which reacts with isoeyanates which is located near one end of the chain such that the polymer chain(s) such that after said group reacts with an isocyanate on the essentially linear anchoring backbone segment She solvent-solubilising chain is terminally disposed in relation to the anchoring polymer backbone; and

e) optionally one or more solvent-solubilising chains having at least one polyester, polyether, or polyacrylate chain and about two groups, which react with isoeyanates, which are located near each end of the solubilising chain such that the polyester, polyether, or polyacrylate (polyacrylic) chain can connect to two separate anchoring backbone segments connecting them. For the purposes of this application, it is desired that the isocyanate reactive groups of component (e) be near separate ends of the polymer rather than both at one end, to avoid component (e) functioning as a solubilising chain laterally attached to two essentially linear anchoring backbone segments where

they are connected via component (e). Further, it is anticipated tbat component (e) may be a polyester or polyacrylatc when component (d) is a polyether (similarly (e) may be a polyethcr or polyester when (d) is a polyacrylate) and (similarly when (d) is a polyester then (e) may be a polyacrylate or polyether).

[0006] An inert solvent may be added before, during or after formation of the anchoring polymer segment and/or the dispersant in order to control viscosity. Examples of suitable solvents are acetone, methylethylkctone, dimethyl formamide, dimethylacetamide, diglyme, N-methylpyrroIidone, butylacetate, methoxypropyl acetate, ethylacetate, ethylene and propylene glycol diacctates, alkyl ethers of ethylene and propylene glycol acetates, toluene and xylene. Preferred solvents are ethyl acetate, butyl acetate, methoxy propylacetate. Isocyanate reactive solvents may be added after the isocyanate reaction is complete, for example alcohols. Preferred alcohols are methanol, ethaπol, propanol, bυtanol, hcxanol and butoxyethanol. Especially preferred are butoxyethanol and propanol,

[0007 j Component (c), if present, is used primarily as a chain extender for the anchoring segment to alter the solubility of the anchoring segment. In one embodiment, the dispersant contains none of component (C), In that embodiment, the anchoring segment consists essentially of the reaction product of components (a) and (b). In one embodiment, these can have a molecular weight between 32 to less than 500 Dalton and desirably have a functionality of isocyanate reactive groups of about 2 per molecule. These include diamines or diols. Examples of suitable diamines for component (c) are ethylene diamine, 1 ,4-butane diamine and 1,6-hexane diamine, Examples of suitable diols for component (c) are 1,6-hexanediol, 1 ,4-cyclohexanedimethanol (CHDM), 1 ,2- dodccancdiol, 2 -phenyl- 1 ,2-propanediol, 1 ,4-benzene dimethanol, 1 ,4-butanediol and neυpentyl glycol. It is anticipated that for some pigments it may be desirable to incorporate some υrethane formative component to alter the anchoring segment (i.e., the essentially linear anchoring backbone segment with laterally attached tertiary amine groups). For the purpose of this application, diols or diamines which fit the description of component (e) will not be considered to be a component (c) but rather a component (e) to avoid having any confusion.

[0008{ These components are generally combined in various orders of addition under substantially anhydrous conditions and in an inert atmosphere which is typically a temperature between 0 and 130 ⁰ C, optionally in the presence of an inert solvent and optionally in the presence of a catalyst. The inert atmosphere may be provided by any of the inert gases of the Periodic Table but is preferably nitrogen. Particularly preferred catalysts are tin complexes of aliphatic acids such as dibutyl tin dilaurate (DBTDL) and tertiary amines.

[0009] In one embodiment, component b) is quaternized before or after incorporation into the PU. In one embodiment, it is especially preferred that component b) is quaternized after incorporation into the PU. The amount of quaternization is dependent on the amount needed on average to get good anchoring to the selected/preferred pigment or particulate. Inclusion of the quaternized tertiary nitrogen atoms pendant from the essentially linear anchoring backbone in the polyurethane dispersant has been found to improve the colloidal stability of the dispersion of some particulate solids in organic liquids, in one embodiment, the amount of nitrogen in tertiary amine groups (optionally quaternized) in the polyurethane dispersant remote (also referred to as pendant or separated) from the linear backbone is preferably from about 1 to about 4 wt.%, more preferably from 1.5 to 3.5 wt.%, and in embodiments where more than 50 mole % is quaternized, and from about 1.5 to 2.5 wt.% and in embodiments where less than 50 mole % is quaternized from about 2.5 to about 3.5 wt.% based on the weight of the essentially linear anchoring backbone segment. The polyurethane dispersant may also optionally contain other tertiary amine groups which are incorporated in the linear anchoring backbone but these were not intended to be counted towards the above specified amounts of nitrogen atoms in tertiary amine groups.

[0010] The tertiary amine may be quaternized with any known quaternizing agent. Preferred quaternizing agents are alkyl halides, aralkyl haϋdes, dialkyl carbonates, dialkyl sulphates or epoxides. Particularly preferred quaternizing agents are dimethyl sulphate, benzyl chloride or styrene oxide. It is preferred that the tertiary amine groups within the anchoring segment are quaternized to some extent. In one embodiment, the extent of quaternization of the tertiary amine group pendant (e.g., separated or remote) from the anchoring segment and/or polyurethane dispersant is >10%, in another

embodiment > 20 or >30 %, and in more preferred embodiments for some pigments the extent of quaternization is >45 or >60% and most preferred that it is >80% on a mole basis of the remote tertiary amine groups,

[0011] In one embodiment, it is preferred that R ^γ contains on average 2 groups that react with isocyanates.

[0012J An acid may be added to form a salt with the tertiary amine moiety in component b).

[0013] In one embodiment, the non-aqueous composition optionally contains 5 wt % or less water, preferably less than 2 wt.%, more preferably less than 0.5 wt.% and most preferably no water based on the total weight of all solvents in the composition. [0014] Preferably, component (a) is a diisocyanate or mixtures of diisocyanates such as toluene diisocyanate (TDI). isophorone diisocyanate (IPDI) ₅ hexanediisocyanate (HDI), α,α-tetramethylxy!ene diisocyanate (TMXDl), diphenyImethane-4,4 ^' - diisocyanate (4,4'-MDI), diρhenyImcthane-2,4 -diisocyanate (2,4'-MDI) and dicyclohexylmcthane-4,4 -diisocyanate (HMDI). Preferably, component (a) is either TDI or IPDl or MDI. TDI is especially preferred.

[0015] The mole % isocyanate groups of component a) reacted with isocyanate reactive groups of component (b) in one embodiment is desirably about 5 to 95 mole %, in another embodiment from 50-95%, and in another embodiment 75-95% and even more preferably 80-95%. The residual isocyanate groups will generally be reacted with a υrethane formative component (c) or with solvent-solubilising chains (d) and/or optional component (e). In one embodiment, the NCO:OH ratio is allowed to go above 1 : 1 , since it is conventional in urcthane chemistry to use an excess of isocyanate in case some of the active isocyanate groups are consumed or converted to other groups such as groups reactive with isocyanate by reactions with adventitious water in reactor systems. [0016] The structure of component b) is such that when it is incorporated into the polyurethane through reaction with isocyanates a tertiary amine group derived from component b) is laterally attached to the anchoring backbone such that the tertiary nitrogen atom is separated by at least one atom from the closest atom on the backbone of the essentially linear anchoring backbone segment. It is more preferred that the tertiary

nitrogen atom is separated by at least two atoms from the closest atom on the backbone and especially preferred that the tertiary nitrogen atom is separated by at least 3 atoms from the closest atom on the backbone. It is preferred the tertiary nitrogen atom is separated by less than 20 atoms from the closest atom on the backbone. It is more preferred the tertiary nitrogen atom is separated by less than 15 atoms from the closest atom on the backbone. It is especially preferred the tertiary nitrogen atom is separated by less than 10 atoms from the closest atom on the backbone. Such tertiary amines laterally attached are thought to provide better anchoring to some particulate solids. The tertiary amine may also be partially or fully qυatemized to form a quaternary ammonium salt, In one embodiment, it is desirable that most e.g., at least 80, at least 85, at least 90 or at least 95 mole % of the groups (reactive with isocyanates) of component b) are reacted with isocyanate groups to form the essentially linear anchoring backbone segment. For the purpose of this application, a backbone atom is considered to be the atoms of a polymer that form a continuous interconnected chain of atoms between the first atom of the first repeating unit and the last atom of the last repeating unit. Atoms pendant from the backbone such as the methyl group in TDI or CH ₃ in poly(l,2- propylene oxide) will not be considered backbone atoms, but rather will be called pendant moieties. For the purpose of this application backbone segment (especially when referring to the molecular weight of the backbone or backbone segment) will be inteipreted to include not only backbone atoms, but also atoms and lateral structures/moieties pendant from the backbone atoms. For the purposes of this application and claims, the use of the term "essentially linear" to described the anchoring segment will be inteipreted to mean that the components (a), (b), and optionally (c) forming the anchoring segment are generally all difunctioiial reactants such that polymer branching from trifunctional or higher functionality reactants in the anchoring segment is not present in any significant percentage. The presence of laterally attached tertiary nitrogen atoms in small pendant groups is desirable and docs not negate from the term "essentially linear".

[0017] Examples of component (b) are; Products formed from the Michael addition of dialkyiaminoalkylaminos to an α,β-unsaturated carbυnyl compound containing a hydroxy functionality. Some examples of suitable dialkylarainoalkylamincs may be

represented by the formula R ^! (RT)NR ³ NH ₂ where R ¹ and R ² are independently C]-Cf, alkyl moieties, R ¹ and R ² may be taken together to form a cyclic structure containing 5 to 8 carbon atoms. R ^~ is Cj to C ₁₂ linear or branched alkylenc. Examples of suitable α,β-unsaturated carbonyl compound containing a hydroxy functionality include hydroxyalkyl acrytates such as hydroxyethyl aery] ate, hydroxypropyl acrylate or hydroxybutyl acrylate. A preferred example of component c) is 2 -hydroxyethyl 3-{[3- (dimethy1amino)propyt]aiτ>ino}propanoate (compound Z) formed by the reaction of dimcthylaminopropylamine with 2 -hydroxyethyl acrylate as illustrated below.

compound Z

1 J'- {[3-(dimethylamino)-propyl]imino}bis-2-propanol

Diethylamino- 1 ,2-propanedioI.

\

H — -1 OH

HO

[0018] The Michael addition product of a dialkylaminoalkyl acrylate with an amino alcohol. Examples of dialkylaminoalkyl acrylates include dimethylaminoethyl acrylate, dimethyl aminopropyl acrylate, dicthylaminoethyl acrylate and diethylaminopropyl acrylate. The Michael addition is illustrated in the following reaction scheme using dimethylaminoethyl acrylate and an amino alcohol.

[0019] Examples of amino alcohols include Cl -Cl 2 alkanolamines where R - (CH ₂ )n and 0 < n < 1 1 or aminoethoxycthanol where R = CH ₂ OCH ₂ CH ₂ . 2,2- Bis((diethylaminojmethyl)-l ,3-propanediol which is an example which would yield 2 pendant tertiary nitrogens in the polyurethane.

[0020] Compounds obtainable or obtained by the Michael addition reaction of two moles of a dialkylaminoalkylarnine with one mole of an unsaturated compound of the formula 5 as described above,

wherein Q, T and R ⁷ are as defined hereinbefore. Examples of unsaturated compounds of Formula 5 are especially diacrylates wherein T is a CVio-alkylene residue, a polyoxyalkylene residue or an oxyethylated Bisphenol A residue.

[0021] Component (d) is a polyether, polyester or polyacrylate which contains about one group that reacts with isocyanates. Preferable, the group is located at the chain end

of the polymer. Preferably, the group is a hydroxyl or amine group, more preferably a hydroxyl group. These groups that react with isocyanates are also referred to as groups with a Zerewitinoff hydrogen. Zerewitinoff hydrogen in urethane chemistry are known to exist on OH, SH, <NH, and MH ₂ . For the purposes of this application, we are interested in the hydroxyl and amine groups that are reactive with isocyanates. The preferred number average molecular weights of the poly ether, polyester or polyaerylate are 500-20,000, more preferable 500-10,000 and most preferably 500-5000 Dallon. Even more preferably 1000-4000 molecular weight. In order to control the structure of the dispersant, it is desirable that component (d) only has on average one group that reacts with the isocyanates under the reaction conditions used to form the dispersant (linear anchoring segments). Having only one isocyanate reactive group per each component (d) promotes the component (d) being a terminal solubilising group from the anchoring segment rather than a chain extender between two linear anchoring segments. [0022] Component (e) is a solvent-solubilising polycther, polyester or polyaerylate chain or mixtures thereof which contains about two groups, which reacts with isocyanates. Preferable, the groups are located near the chain ends of the polymer. Preferably, the groups are a hydroxyl and/or amine group, more preferably a hydroxyl group. When component (e) is a diol, may also be a polyether such as a poly (C ₂ . ₄ - alkylene glycol), a polyester or polyaerylate diol. The polyaSkylene glycol may be a random or block (co)polymer containing repeat ethyleneoxy. propyleneoxy or butyleneoxy groups, including mixtures thereof. In situations where the diol or diamine is a solubilising poly(Ci. ₄ alkylencine glycol), a polyester, or a polyacrylic diol, the polyurethane dispersant comprises two or more essentially linear anchoring backbone segments chain extended with one or more difunctional solvent-solubilising chains (e). The preferred number average molecular weights of the polyether, polyester or polyaerylate are 500-20,000, more preferable 500-10,000 and most preferably 500-5000. Even more preferably 1000-4000 Dalton molecular weight. [0023] In order to control the structure of the dispersant, it is desirable that component (e) only has on average two groups that reacts with the isocyanates under the reaction conditions used to form the dispersant (linear anchoring segments). Having two isocyanate reactive group per each component (e) allows component (e) to function as a

chain extender between two linear anchoring segments. Component e) is only present in embodiments where two or more linear anchoring backbone segments are desired. At this time, it is not anticipated to use component e) when the intended product has only a single anchoring backbone segment and two terminal soltibilising chain ends, [0024] In one embodiment where the terminal sol utilising chain (d) and/or component (e) is a polyacrylate (sometimes referred to as polyacrylic), it is preferably obtained from the polymerisation of an alkyl acrylate or alkyl methacrylatc. The poly alkyl(meth)acrylate may be prepared by the free radical polymerisation of (meth) acrylate monomer(s). Component (d) may be prepared in the presence of a moπohydroxyl functional chain transfer agent for example raercaptoalcohoϊs to impart mono-functionality. Other vinyl monomers such as styrene, vinyl esters, etc., could be copolymerized into the polyacrylate provided that they do not significantly negatively affect solubility in the selected solvent system for the dispersant or interact negatively with the tertiary and'Or quaternized tertiary amines. In one embodiment, the non- acrylate monomers are less than 30, less than 20 and less than 10 mole percent of the total repeating units of the polyacrylate. Preferably, the mercaptoalcohols include 2-niercaptoethanol, 1 -mercapto-2-propanol, 3-mercapto-l -propanol 1 -mercapto-2- propanol 4-inercapto-l -butanol, 6-mercapto-l-hexanol, 4-mercaptophenol. Preferably, the polymerisation can be performed in the presence of a non-functional radical initiator, for example, azo type initiators. Examples of suitable azo initiators include 2,2'- azobis(4-methoxy-2,4-dimethylvaleronitriIe), 2,2'-azobis(2.4-dimethyl-valeronitrile, 2,2'- azobisisobutyronitrile, dimethyl 2,2'-azobisisobutyrate, 2,2'-azobis(2-methyl- butyronitrile), 1.1 '-azobis( 1 -cyclohexanecarbonitrile), 2-(carbamoylazo)-isobutyronitriIe, 2,2'-azobis(2,4,4-trimethyI-pentane. The preferred initiators are 2,2'- azobisisobutyronitrile, and l ,l ^r -azobis( l -cyclohexanecarbonitrile). To obtain a higher hydroxyl content polymer, a mercaptoalcohol can be used in the presence of a hydroxyfunctional initiator, for example, 2,2'-azobis[2-methyl-N-{2-hydroxyethyl) propionamidcj.

{0025] Alternatively, the poly alkyl(meth)acrylate may be prepared by any polymerisation technique such as Ionic Polymerisation, Group Transfer Polymerisation (GTP) , Atom Transfer Radical Polymerisation (ATRP), Nitroxide Mediated Radical

Polymerisatioπ (NMRP) or Radical Addition Fragmentation Polymerisation (RAFT) using a functional initiator or chain terminator thai has one group reactive with isocyanates, for example, hydroxyl functional RAfT agents. RAFT agents are disclosed in numerous publications such as VVO 2006/020281 and US 7,279,591 , [0026] Isocyanate reactive functionality may be introduced into the polyacryfate solubilising chain (cither component (d) or (e)) before or after the polymerisation of the pol y( m eth) acryl ate ,

[0027] The total weight percentage of the solvent-soluble (solubilising) terminal chains of component (d) (e.g., polyether, polyester, and/or polyacrylate) in the polyurethanc dispersant in one embodiment is preferably not less than 5%, in another embodiment not less than 20%, more preferably not less than 30% and especially not less than 40% by weight of the polyurethane dispersant. It is also preferred that the total weight percentage of solvent-soluble terminal chains in the polyurethane dispersant is not greater than 80%. more preferably not greater than 70%, especially not greater than 60% based on the weight of the dispersant. In one embodiment, the total weight percentage of solvent-soluble terminal chains m the polyurethane dispersant is not greater than 60%, for instance 40% to 60%. The weight percentages above are not meant to include solubilising chains characterized as component (e). f0028] The polyurethane polymers according to the invention may be prepared by any method known to the art. Typically, the polyurethane dispersant is obtainable or obtained by reacting one or more diisocyanates component (a) with one or more compounds selected from (b), component (d) and optional components (c) and (e). In one embodiment, the monofunctional solvent-solubilising polyether, polyester or polyacrylic chain (d) is introduced at the start of the polyurethane synthesis with (a), (b) and optionally (c) and (e). In another embodiment, component (d) and optionally (e) are introduced after (a), (b) and optionally (e) have been polymerised. [0029] The number average molecular weight of the polyurethane dispersant is preferably not less than 2,000, more preferably not less than 3,000 and especially not less than 4,000, It is also preferred that the number average molecular weight of the polyurethane polymer is not greater than 30.000, more preferably not greater than 20,000 and especially not greater than 15,000 Dalton.

[0030] Whereas, the solvent-solubilising polyester, polyether, or polyacrylate terminal chains of component (d) may contain a second terminal group less reactive with isocyanates than the coupling terminal group, it is much preferred that such terminal solubilising chains carry one terminating group which is not reactive with isocyanates and especially a Ci- ₅₀ -hydrυcarbyl group since this restricts any cross-linking during the preparation of the dispersant. The hydrocarbyl group may be optionally branched alkyl, cycloalkyl, aryl or aralkyl.

[0031] The cycloalkyl group is preferably such as cyclopropyl and especially cyclohexyl. The aryl group is preferably C _ό -io-aryl such as naphthyl and especially phenyl which may be substituted by halogen, C^o-alky! or d^u-alkoxy. The aralkyl group is preferably 2-phenyiethyl and especially benzyl where the phenyl ring is optionally substituted by halogen, Cj- ₂₀ -alkyl or Ci. ₂ o-alkoxy.

[0032] The length of the alkyl terminating group of the polyester, polyether, and/or polyacrylate chain depends to a large extent on the nature of the organic medium. Thus, for example, when the organic medium is a polar organic liquid, the hydrocarbyl group is preferably which may be linear or branched. The hydrocarbyl group includes ethyl, propyl, isopropyl or mixtures thereof. When the polyurethane dispersant contains polyether terminal chains, it is preferred that the terminating alkyl group is C] ₄ alkyl, for instance methyl, because of their ready commercial availability. When the organic medium is a non-polar organic liquid, it is preferred that the terminating alkyl group contains greater than 8 carbon atoms. It is also preferred that the alkyl group is branched since this aids solubility in the non-polar organic liquid,

[0033] In one embodiment, the solvent-solubilising chain of component (d) is a polyether chain, preferably poly(Q>. ₄ -alkylene oxide) which contains less than 60%, more preferably less than 40%, and especially less than 20% by weight ethylene oxide relative to the total weight of the poly (C ₂₄ -alkyIene oxide) chain. The alkyl ene moiety of the (C^-alkyiene oxide) group may be linear or preferably branched and may be obtained by (co)ρolymerisation of alkylene oxides such as ethylene oxide, propylene oxide and butyl en e oxide or from tctrahydrofuran. Copolymers may be random or block copolymers. Preferably, the polyether chain is obtainable from propylene oxide. It is

also prefeiTed that the polyether chain of the dispersant is obtainable from a poty(C ₂ - ₄ - aikylcne oxide) mono-CVio-alkyl ether and especially a C _M alkyl ether such as methyl or butyl ether.

[0034] In one embodiment where a component (e) is present. In another embodiment, optional component (e) is absent. When component (e) is a polyether chain (characterized similarly to component (d) polycthers) except with about 2 groups reactive with isocyanates, the polyether chain for component (e) can be prepared from C ₂ -C4 alkylene oxide monomers added to both ends of a difunctional initiator such as a CI-C _JO diol. This would prepare a diol with C2-C ₄ alkylene oxide repeating units. {0035] In one embodiment, the solvent solubilising chain of component (d) is a polyester. The polyester chain of component (d) is preferably obtainable or obtained from a hydroxy carboxylic acid containing from 1 to 26 carbon atoms or a lactone thereof. The choice of hydroxy carboxylic acid is largely influenced by the nature of the organic medium itself. Where the organic medium is a polar organic liquid, the hydroxy carboxylic acid preferably contains up to 8 carbon atoms, and where the organic medium is a non-polar organic liquid, the hydroxy carboxylic acid preferably contains more than 8 carbon atoms. It is particularly preferred that the polyester chain is obtainable from two or more different hydroxy carboxylic acids or lactones thereof since this aids solubility in the organic medium. The hydroxy carboxylic acid may be saturated or unsaturated, linear or branched. When component (e) is present and comprises a polyester chain, it is made from similar components as polyester chain (d). Of course polyester chains of component (e) arc functionalized with two isocyanale reactive groups.

[0036] Examples of suitable hydroxy carboxylic acids are glycolic acid, lactic acid, 5-hydroxy valeric acid, 6-hydroxy caproic acid, ricinoleic acid, 12-hydroxy stearic acid, 12-hydroxydodecanoic acid, 5-hydroxydodecanoic acid, 5-hydroxydecanoic acid and 4-hydroxydecanoic acid.

[0037] Examples of suitable lactones are β-propiolactone and optionally substituted δ-valerυiactone and ε-caprolactone such as β-methyl-δ-valerolactone, δ-valerolactone. ε-caprolactone, 2-melhyl, 3-methyl, 4-methyI, 5-tert butyl, 7-methyl-

4,4,6-trimethyi- and 4,6,6-trimethyI-ε-capro!actone, including mixtures thereof. Polyester chains derivable from δ-valerolactone and/or ε-caprolactone are especially preferred,

[0038 j By way of an obvious variant, the solvent-solubilising polyester or polycther terminal chains may themselves be mixtures of such chains. Thus, for example, the polyester side chains may contain a poly ether moiety and vice-versa. [0039] As disclosed hereinbefore, the backbone of the anchoring segment is essentially or substantially linear. By this we mean that the reactive components to make the anchoring segment are mostly dirunctional and have very little trifunctiυnal or higher functionality reactants that might cause polymer branching if fully reacted. Therefore, the isocyanates of component (a) from which the dispersant is obtainable preferably have average functionality of from 2.0 to 2.5, more preferably from 2.0 to 2.1 and especially approximately 2.0. Similarly, the component (b) and optional components (c) and (e) in one embodiment preferably individually and/or combined have a functionality of groups reactive with isocyanates from 1.0 or 2.0 to 2.5, more preferably from 1.95 or 2.0 to 2, 1 or 2.2 and especially 2.0.

[0040] In one embodiment, the solvent-solubilising terminal polyester, polyether, and/or polyacrylatc chains are sometimes connected to anchoring backbone by oxygen and/or nitrogen atoms which are the residue of terminating hydroxy and amino (primary and secondary) groups of the polyester, polyether and'or polyacrylate that are reacted with terminal isocyanate groups of the essentially linear anchoring segment. [0041] The particulate solid present in the composition may be any inorganic or organic solid material which is substantially insoluble in the organic medium at the temperature concerned and which it is desired to stabilise in a finely divided form therein.

[0042] Examples of suitable solids are pigments for solvent inks; pigments, extenders and fillers for paints and plastics materials; dyes, especially disperse dyes; optical brightening agents and textile auxiliaries for solvent dyebaths, inks and other solvent application systems; solids for oil-based and invert-emulsion drilling muds; dirt and solid particles in dry cleaning fluids; particulate ceramic materials; magnetic

matcrials and magnetic recording media, fire retardants such as those used in plastics materials and biocides, agro chemicals and pharmaceuticals which arc applied as dispersions in organic media.

[0043] A preferred particulate solid is a pigment from any of the recognised classes of pigments described, for example, in the Third Edition of the Colour Index (1971) and subsequent revisions of, and supplements thereto, under the chapter headed "Pigments". Examples of inorganic pigments arc titanium dioxide, zinc oxide, and iron oxides. {0044] Examples of organic pigments are those from the azo. disazo, condensed a/o, Ihioindigo, indanthrone, isoindanthronc, anthanthrone, anthraquinone. isodibcnzanthrone, triphendioxazine, quinacπdone, perylene, diketopyrrolopyrrol (DPP), and phthalocyanine series, especially copper phthalocyanine and its nuclear halogenatcd derivatives, and also lakes of acid, basic and mordant dyes. Carbon black, although strictly inorganic, behaves more like an organic pigment in its dispersing properties. Preferred organic pigments are phthalocyanincs, especially copper phthalocyanines, monoazos, disazos, indanthrones, aπthranthrones, anthraqui nones, quinacridones, perylene, diketopyrrolopyrrol (DPP), and carbon blacks.

J0045] Pigments with an acidic surface are preferred such as oxidized carbon blacks. [0046 j Other preferred particulate solids are: extenders and fillers such as talc, kaolin, silica, barites, nanoclays, and chalk; particulate ceramic materials such as alumina, aluminium oxide, silica, zirconia, titania, silicon nitride, boron nitride, silicon carbide, boron carbide, mixed silicon-aluminium nitrides and metal titanates; particulate magnetic materials such as the magnetic oxides of transition metals, especially iron and chromium, e.g., gamma-Fc2θ ₃ , FcjO ₄ , and cobalt-doped iron oxides, calcium oxide, ferrites, especially barium ferrites; and metal particles, especially metallic iron, nickel, cobalt and alloys thereof; agrochemicals such as the fungicides flutriafen, carbendazim, chlorothalonil and mancozeb and fire retardants such as aluminium trihydrate and magnesium hydroxide.

[0047] The dispersant and pigment/particulate may eventually be used with an organic media, that may or ma> not be similar to the medium used to form the dispersant, to form a millbase, a coating material, an ink, or other useful blend. The organic medium present in the composition is preferably a polar organic medium or a

substantially non-polar aromatic hydrocarbon or halogenated hydrocarbon. By the term "polar" in relation to the organic medium is meant an organic liquid or resin capable of forming moderate to strong bonds as described in the article entitled "A Three Dimensional Approach to Solubility" by Crowley et al., in Journal of Paint Technology, Vol. 38, 1966, at page 269. Such organic media generally have a hydrogen bonding number of 5 or more as defined in the above mentioned article. [0048J Examples of suitable polar organic liquids are amines, ethers, especially lower alkyl ethers, organic acids, esters, ketones, glycols, glycol ethers, glycol esters, alcohols and amides. Numerous specific examples of such moderately strongly hydrogen bonding liquids arc given in the book entitled "Compatibility and Solubility" by Ibert Mellan (published in 1968 by Noyes Development Corporation) in Table 2.14, on pages 39-40, and these liquids all fall within the scope of the term polar organic liquid as used herein.

[0049] Preferred polar organic liquids are dialkyl ketones, alkyl esters of aikane carboxylic acids and alkanols, especially such liquids containing up to, and including, a total of 6 carbon atoms. As examples of the preferred and especially preferred liquids, there may be mentioned dialkyl and cycloalkyl ketones, such as acetone, methyl ethyl ketone, diethyl ketone, di-isopropyl ketone, methyl isobuty! ketone, di-isobutyl ketone, methyl isoamyl ketone, methyl n-amyl ketone and cyelohexanone; alkyl esters such as methyl acetate, ethyl acetate, isopropyl acetate, butyl acetate, ethyl formate, methyl propionate, methoxy propylacetate and ethyl butyrate; glycols and glycol esters and ethers, such as ethylene glycol, 2-cthoxyethanol, 3-methoxypropylpropanol, 3-ethoxypropylpropanol, 2-butoxyethyl acetate, 3-methoxypropyl acetate, 3-ethoxypropyl acetate and 2-ethoxyethyi acetate; alkanols such as methanol ethanol, n-propanol, isopropanol, n-butanol and isobutanol and dialkyl and cyclic ethers such as diethyl ether and tetrahydrofuran.

[0050] The substantially non-polar, organic liquids which may be used, either alone or in admixture with the aforementioned polar solvents, are aromatic hydrocarbons, such as toluene and xylene, aliphatic hydrocarbons such as hexane, heptane, octane, decane, petrolium distillates such as white spirit, mineral oils, vegetable oils and halogenated

aliphatic and aromatic hydrocarbons, such as trichloro-ethylene, perchloroethylene and chSorobenzene.

[0051] The dispersant and pigment/particulate may eventually be blended with a resin to form a millbase, a coating material, an ink, or other useful blend. Examples of suitable polar resins, as the medium for the dispersion form of the present invention, are film- forming resins such as arc suitable for the preparation of inks, paints and chips for use in various applications such as paints and inks. Examples of such resins include polyamides, such as Versamid ^ϊM and Wolfamid™, and cellulose ethers, such as ethyl cellulose and ethyl hydroxyethyl cellulose. Examples of paint resins include short oil alkyd/melamine-formaldehyde, polyester/melamine-formaldehyde, thermosetting aerylic/melamine-foπnaldehyde, long oil alkyd and multi-media resins such as acrylic and urea/aldehyde.

[0052J The resin may also be an unsaturated polyester resin including the so-called sheet moulding compounds and bulk moulding compounds which may be formulated with reinforcing fibres and fillers. Such moulding compounds are described in DE

3,643,007 and the monograph by P. F. Bruins entitled "Unsaturated Polyester

Technology", Gordon and Breach Science publishers, 1976, pages 21 1 to 238.

[0053] if desired, the dispersions may contain other ingredients, for example, resins

(where these do not already constitute the organic medium) binders, fluidising agents

(such as those described in GB-A-1508576 and GB-A-2108143), anti -sedimentation agents, plasticizers, levelling agents and preservatives.

[0054] The composition typically contains from 5 to 95% by weight of the particulate solid, the precise quantity depending on the nature of the solid and the relative densities of the solid and the organic medium. For example, a composition in which the solid is an organic material, such as an organic pigment, preferably contains from 15 to

60% by weight of the solid whereas a composition in which the solid is an inorganic material, such as an inorganic pigment, filler or extender, preferably contains from 40 to

90% by weight of the solid based on the total weight of composition,

|0055] The composition is preferably prepared by milling the particulate solid in the organic medium at a temperature which is not greater than 40 ⁰ C and especially not

greater than 3O ⁰ C. However, when the solid is a crude phthalocyanine pigment such as copper phthalocyanine, it is sometimes preferable to carry out the milling in an organic liquid at a temperature between 50 and ] 50°C since greener and brighter shades may be obtained. This is particularly the case where the organic liquid is a high boiling aliphatic and/or aromatic distillate.

{0056] The composition may be obtained by any of the conventional methods known for preparing dispersions. Thus, the solid, the organic medium and the dispersant may be mixed in any order, the mixture then being subjected to a mechanical treatment to reduce the particles of the solid to an appropriate size, for example, by ball milling, bead milling, gravel milling or plastic milling until the dispersion is formed, Alternatively, the solid may be treated to reduce its particle size independently or in admixture with either of the organic medium or the dispersant _* the other ingredient or ingredients then being added and the mixture being agitated to provide the dispersion. [0057] If the composition is required in dry form, the liquid medium is preferably volatile, so that it may be readily removed from the particulate solid by a simple separation means such as evaporation. It is preferred, however, that the composition comprises the liquid medium.

[0058] If the dry composition consists essentially oi ^' the dispersant and the particulate solid, in one embodiment, it preferably contains at least 0.2%, more preferably at least 0.5% and especially at least 1.0% dispersant based on weight of the particulate solid. In one embodiment, the dry composition contains not greater than 100%, preferably not greater than 50%, more preferably not greater than 20%, and especially not greater than 10% by weight dispersant based on the weight of the particulate solid. [0059] As described hereinbefore, the compositions are particularly suitable for preparing mill-bases where the particulate solid is milled in a liquid medium in the presence of both a particulate solid and a film-forming resin binder. [0060] Thus, according to a still further aspect of the invention there is provided a mill-base comprising a particulate solid, dispersant and a film-forming resin.

[0061] Typically, the mill-base contains from 20 to 70% by weight particulate solid based on the total weight of the mill-base. Preferably, the particulate solid is not less than 30 and especially not less than 50% by weight of the mill-base.

[0062] The amount of resin in the mill-base can vary over wide limits but is preferably not less than 10%, and especially not less than 20% by weight of the continuous/liquid phase of the mill-base. Preferably, the amount of resin is not greater than 50% and especially not greater than 40% by weight of the continuous/liquid phase of the mill-base,

[0063] The amount of dispersant in the mill-base is dependent on the amount of particulate solid but is preferably from 0.5 to 5% by weight of the mill-base.

J0064] In one embodiment, the polyurethane dispersant according to the invention is that it comprises a predominantly linear anchoring polymer backbone containing the defined amount of laterally attached tertiary or quaternized tertiary amino groups and about two terminal soivent-solubilising chains of poly (alkylene oxide), polyester, poly(alk)acrylate or polyolefϊn. In one embodiment, there are chain extending solvent - solubilising chains that connect essentially linear anchoring segments to each other.

There will thus be many variants which will be obvious to the skilled addressee regarding the ratio of isocyanate groups to isocyanate reactive groups.

[0065] As noted hereinbefore, some of the polyurethane dispersants are novel.

Hence, as a further aspect of the invention, there is provided a polyurethane dispersant having an essentially linear anchoring backbone containing the defined amount of laterally attached tertiary or quaternized tertiary amino groups and terminally attached soivent-solubilising chains from polyether side chains of poly(C ₂ -4-alkylene oxide) which contains less than 60% by weight ethylene oxide relative to the ρoly(C2 _-4 -alkylene oxide) chain.

[0066] As a still further aspect of the invention, there is provided a polyurethane dispersant having an essentially linear anchoring backbone and terminally attached soivent-solubilising polyester and/or polyacrylate chains.

lndustrial Application

[0067] Dispersions and mill bases made from the composition of the invention are particularly suitable for use in paints, including high solids paints, inks, especially flexographic, gravure and screen inks, colour filter layers for display screen equipment and non-aqueous ceramic processes.

[0068] The following examples provide an illustration of the invention. These examples are non exhaustive and are not intended to limit the scope of the invention.

Unless expressed to the contrary, all references are to parts by weight,

[0069] All polymerisation were characterised by size exclusion chromatography using a Waters 2690 Separations module with Polymer Laboratories mixed d columns and THF eluent with 1 % triethyl amine. The molecular weights have been compared to polystyrene standards. Solids contents have been determined by gravimetry.

Intermediate A Monohydroxy Poly(butyl methacrylate)

|0070] Butyl methacrylate (369 parts), methoxy propyl acetate (369 parts) and 2-mercaptoethanol (9.21 parts) were stiiτed together in a RB flask and heated to 90 ^u C under nitrogen. Azobis(cyclohexane-l -carbonitrile) (3.69 parts) was then charged and the reaction vessel maintained at 90 ^v> C for 20 hrs. After cooling, the resulting polymer was a liquid with solids content of 50.6%. The product was characterised by size exclusion chromatography and had Mn = 2900 and Mw = 6200, This is Intermediate A.

Intermediate B Monohydroxy Polycaprolactone

[0071] i-Dodecanol (13.2 parts) and ε-caprolactone (200 parts) were stirred together under nitrogen at 15O ⁰ C. Zirconium butoxide catalyst (1.1 parts) was added and the reactants were heated to I SO ⁰ C and stirring maintained for 20 hours. After cooling to 2O ⁰ C, the resulting polyester was obtained as a waxy solid. This is Intermediate B.

Example Dispersant 1 with Poly(bυtyl methacrylate) Solubilising Segment [0072] Intermediate A (poly(butyl methacrylate)) (100 parts), l,l'- {[3- (dimethylamino)-propyl]imino) bis-2-propanol (15.42 parts), methoxy propyl acetate

(29,09 parts) were stirred together in a RB flask and heated to 7O ⁰ C under nitrogen. ToIy ene diisocyanatc (13.67 parts) was then charged over 15 minutes and the temperature maintained at 70"C for 2 hrs until no isocyanale remained. 95.68 parts of the resulting solution were removed from the reaction vessel. The product was characterized by size exclusion chromatography and gave molecular weight values of Mn = 5000 and Mw = 9600. Benzyl chloride (1.61 parts) was charged to the residual solution (62.5 parts) which was held at 7O ⁰ C for 20 hrs with agitation to yield a quatemized PL (polyurethane) dispersant with solids content 52.5%.

Example Dispersant 2 with Polycaprolactone Solubilising Segment [0073 J Intermediate B (polytcaprolactone)) (61.23 parts), l,l'- {[3-(dimethylamino)- propyl]imino}bis-2-propartol (20.05 parts), methoxy propyl acetate (99.08 pans) were stirred together in a RB flask and heated to 7O ⁰ C under nitrogen. Tolyene diisoeyanate ( 17.71 parts) was then charged over 15 minutes and the temperature maintained at 70°C for 2 hrs until no isocyanate remained. The product was characterized by size exclusion chromatography and gave molecular weight values of Mn = 6500 and Mw = ^■ 15400. Benzyl chloride (10.46 parts) and methoxy propyl acetate (10.46 parts) were charged to the residual solution (198.16 parts) which was held at 70 ⁰ C for 20 hrs with agitation to yield a quatemized PU dispersant with solids content 50%.

Comparative Example A with Polycaprolactone Solubilising Segment and no Pendant Tertiary or Quatemized Amine

[0074] Intermediate B (poly(caprolactone)) (70.65 parts), N-Methyldiethanolamine (12,63 parts), methoxy propyl acetate (103.79 parts) were stirred together in a RB flask and heated to 7O ⁰ C under nitrogen. Tolyene diisoeyanate (20.51 parts) was then charged over 15 minutes and the temperature maintained at 7O ⁰ C for 2 hrs until no isocyanate remained. The product was characterized by size exclusion chromatography and gave molecular weight values of Mn - 8200 and Mw - 18900. Benzyl chloπde (12.06 parts) and methoxy propyl acetate (12.06 parts) was charged to the residual solution (207.58 parts) which was held at 7O ⁰ C for 20 hrs with agitation to yield a quatemized PU dispersant with solids content 42.8%.

2 _^

Pigment Dispersion Performance Resin Containing Milling Test [0075] Dispersions were prepared by separately dissolving example dispersants 1 and 2 and comparative dispcrsant example A (2.89 parts at 50% active) in butyl acetate (1 1 .95 parts). Macrynal SMC565 (10.05 parts ex Cytec) and 3mm glass beads (125 parts) and red pigment (7.23 parts, Oromopthal Red A3B ex Ciba ) were added and the contents were milled on a scandex shaker for 1 hr. The viscosity of the mill base was measured using a TA Instruments Rh eo meter as the shear rate was increased from 37.6 to 2392.0 s ^*1 . The example dispersants 1 and 2 produced mill base viscosities under 2 Pa.s at a shear rate of 37.6 s-1 where as the comparative dLspersant example A produced mill base \ iscosities over 6 Pa.s at the shear rate of 37.6 s- i .

Determination of Mill Base Viscosity

δ Example 1 - Example 2 s Comparative Example 1

10.0 100.0 1000 0 10000.0 Shear rate S-1

[0076] ^' 1 he mill bases (1.93 parts) were let down into a solution of Macrynal

SMC565 (2.94 parts ex UCB Chemicals) and Desmodur N3390 (0.33 parts, ex Bayer) in butyl acetate (0.85 parts) then drawn down onto black and white card using a number 3

K-bar.

[0077] The coatings produced with example dispersants 1 and 2 produced glossy coatings which were transparent and contained few flocculated particles. The coating

produced with the comparative dispersant example A was lower in gloss and produced a hazy coating with many flocculated particles.

Gloss and haze were measured using a B yk~ Gardner Haze Gloss meter. Transparency and the number of flocculated particles were assessed visually.

Intermediate C, Polycaprolactone-co-valerolactυne

[0078] 1-Dodecanol (1 14.6 parts), ε-caprolactonc (666.73 parts) and δ-valerolactone (215.44 parts) were stirred together under nitrogen at 15O ⁰ C. Zirconium butoxide catalyst {4 parts) was added and the reactants were heated to 18O ⁰ C and stirring maintained for 20 hours. After cooling to 2O ⁰ C, the resulting polyester was obtained as a waxv solid. This is Intermediate C.

Example 3

[0079] Tolyene diisocyanate (35.00 parts) and mcthoxy propyl acetate (64.99 parts) were stirred together in a RB flask and heated to 7O ⁰ C under nitrogen. Polypropylene glycol monobutyl ether (90.11 parts, Breox Lubricant B335 ex Cognis) and mcthoxy propyl acetate (100 parts) were then added over 45 minutes and the temperature maintained at 7O ⁰ C. The reaction was cooled to 40 ⁰ C and l,r~ {[3-(dimethylamino)- propyl]irnino}bis-2-propanol (39.89 parts) was charged over 30 minutes maintaining the temperature at 4O ⁰ C. The reaction mixture was then heated to 7O ⁰ C for 2 hrs until no isocyanate remained. Methoxy propyl acetate (220 parts) was then added to dilute the product to a solids content of 30%. 400 parts of the resulting solution were removed from the reaction vessel. The product was characterized by size exclusion chromatography and gave molecular weight values of Mn - 5700 and Mw = 14200. Benzyl chloride (3.78 parts) was charged to the residual solution ( 150 parts) which was

held at 7O ⁰ C for 20 hrs with agitation to yield a quaternised PU dispersant. The final product had a solids content 32.4%.

Example 4

[0080} Intermediate A (poly{butyl methacrylate)) (5135 pans, 50% solids), l,l '-{[3- (dimcthylamino)-propyl]imino)bis-2-propanol (17.91 parts) and methoxy propyl acetate (32.91 parts) were stirred together in a RB flask and heated to 70 ⁰ C under nitrogen. ^' Polyene diisocyanafe (15.00 parts) was then charged over 15 minutes and the temperature maintained at 7O ⁰ C for 2 hrs until no isocyanatc remained. Ethylene glycol butyl ether (40 parts) and methoxy propyl acetate (37 parts) were then added to dilute the product to a solids content of 30%. 144.17 parts of the resulting solution were removed from the reaction vessel. The product was characterized by size exclusion chromatography and gave molecular weight values of Mn - 1800 and Mw = 8300. Benzyl chloride (0.66 parts) was charged to the residual solution (50 parts) which was held at 70 ⁰ C for 20 hrs with agitation to yield a quatemized PU (polyurethane) dispersant with solids content 32.82%.

Example 5

[0081 J Intermediate C (poly(caprolactone-co-valerolactone)) (56 parts), 1,1 '-{[3- (dimethylaniino)-propyl]imino)bis-2-propanoi (26.4 parts) and methoxy propyl acetate (100.48 parts) were stirred together in a RB flask and heated to 70 ⁰ C under nitrogen. Tolyenc diisocyanate ( 18.1 parts) was then charged over 15 minutes and the temperature maintained at 7O ⁰ C for 2 hrs until no isocyanate remained. 180 parts of the resulting solution were removed from the reaction vessel and the product was characterized by size exclusion chromatography and gave molecular weight values of Mn = 1400 and Mw = 4700. Benzyl chloride (1.22 parts) was charged to the residual solution (20 parts) which was held at 70"C for 8 hrs with agitation to yield a quatemized PU dispersant with solids content 56.27%.

Example 6

[0082| Intermediate A (poly(butyl methacrylate)) (136.59 parts, 50% solids), 1 , 1 '- {[3-(dimethylamino)-propyl]iπiino}bis-2-propanol (23.82 parts), methoxy propyl acetate (53.82 parts) were stirred together in a RB flask and heated to 70 ⁰ C under nitrogen. Suprasec 2004 (30.00 parts, ex Huntsman) was then charged over 30 minutes and the temperature maintained at 7O ⁰ C for 2 hrs until no isocyanate remained. Ethylene glycol butyl ether (85 parts) and methoxy propyl acetate (77 parts) were then added to dilute the product. The resulting product had a solids content of 30%. 276 parts of the resulting solution were removed from the reaction vessel. The product was characterized by size exclusion chromatography and gave molecular weight values of Mn = 3800 and Mw - 8300. Benzyl chloride (1.98 parts) was charged to the residual solution (130 parts) which was held at 7O ⁰ C for 20 hrs with agitation to yield a quaternized PU (polyurethane) dispersant with solids content 31.0 %.

Dispersion testing f{)083] Dispersions were prepared by dissolving dispersants 3-6 (0.5 parts based on 100% active solution) in butyl acetate (7.0 parts). 3mm Diameter glass beads (20 parts) and red pigment (2.0 parts, Cromopthal red A2B, ex Ciba) were added and the contents milled on a horizontal shaker for 16 hours. The resultant mill bases exhibited excellent fluidity where as the comparative example produced a thick immovable gel as described in the following table.

J0084] Each of the documents referred tυ above is incorporated herein by reference. Except in the Examples, or where otherwise explicitly indicated, all numerical quantities in this description specifying amounts of materials, reaction conditions, molecular weights, number of carbon atoms, and the like, are to be understood as modified by the word "about." Unless otherwise indicated, each chemical or composition referred to herein should be interpreted as being a commercial grade material which may contain the isomers, by-products, derivatives, and other such materials which are normally understood tυ be present in the commercial grade. However, the amount of each chemical component is presented exclusive of any solvent or diluent oil, which may be customarily present in the commercial material, unless otherwise indicated. It is to be understood that the upper and lower amount, range, and ratio limits set forth herein may be independently combined. Similarly, the ranges and amounts for each element of the invention may be used together with ranges or amounts for any of the other elements. As used herein, the expression "consisting essentially of permits the inclusion of substances that do not materially affect the basic and novel characteristics of the composition under consideration.

[0085] While the invention has been explained in relation to its preferred embodiments, it is to be understood that various modifications thereof will become apparent to those skilled in the art upon reading the specification. Therefore, it is to be understood that the invention disclosed herein is intended to cover such modifications as fall within the scope of the appended claims.