The use of certain colour bases (carbinols) for the preparation of organic solvent-based inks is'already disclosed e. g-. in FATIPEC CONGRESS 1976, 13,554 where dyes and associated carbinols of the triarylmethane, diarylmethane and xanthene families are combined with coloured pigment compositions containing a so-called printing resin. The use of azo or methine dyes and their precursors (carbinols) is not mentioned, and further, the effects, e. g. colour strength, can be visibly increased only by the addition of organo-soluble (touluene soluble) surfactants (e. g. dodecyl benzene sulfonic acid).

While the use of the dye precursors of the above-mentioned colour families was not fully convincing, it has now been found that by using a particular group of basic red and blue dyes, prepared from dye precursors, for the preparation of organic solvent-based printing ink compositions, outstanding effects can be achieved.

Accordingly, it is the main object of the present invention to provide said printing ink compositions. Other objects of the present invention relate to processes for the preparation of these printing ink compositions as well as methods of using them.

These and other objects of the present invention will be described in the following.

Therefore, in a first aspect, there is provided an organic solvent-based printing ink composition which comprises (1) a cationic dyestuff of the formulae (1) to (4) or a mixture thereof, wherein Ri-Rig are independently of one another hydrogen, substituted or unsubstituted alkyl, alkoxy, cycloalkyl, aryl, heteroaryl or allyl, R2 and R3, R4 and R5 or R17 and Ris may be combined together to form a ring, further R6, R7, Rg, R10, R12, R14, R15 and R16 are independently of one another halogen, cyano, nitro, aryloxy, alkenyl, alkenoxy, alkoxcarbonyl, aryloxycarbonyl, acyloxy, acyl, alkylthio, arylthio, acylamino, alkylsulfonyl, arylsulfonyl or thiocyano, any two of each of R6, R7, Rg, Rio, Razz Ri4 R15, or Rie may be combined together to form a homocyclic or heterocyclic aromatic or non-aromatic ring, m, n and q are integers of 0 to 4, p and k are integes of 0 to 5, t is an integer of 1 to 20, y and w are integers of 0 to 3, z is an integer of 0 to 4, Xi"is an organic anion derived from a resin acid, and X2 is an organic anion, (2) an organic solvent, (3) an organic acid, or a salt thereof, soluble in the organic solvent, and (4) optionally a pigment.

Alternatively, component (3) can be an ink vehicle (binder) as hereinafter described.

The component (1) dyestuffs are e. g. mono azo dyestuffs (formula (3) ), and methine (polymethine) dyestuffs of formulae (1), (2) and (4).

The substituents Ri-Rie in formulae (1) to (4) are independently of one another hydrogen, further substituted or unsubstituted alkyl or alkoxy which comprises species of e. g. 1 to 20 carbon atoms, preferably of 1 to 10 carbon atoms, which may be linear or branched.

Examples are methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, hexadecyl, octadecyl and the corresponding isomers. The alkoxy species can be listed analogously. Preferred are the lower alkyl/alkoxy (Ca-C4) species, and mostly preferred are methyl and methoxy.

As to the substituted allcy and alkoxy radicals (preferences with regard to the chain lengths as mentioned above) there can be mentioned hydroxyalkyls, halogeno-alkyls (fluoro-, chloro-, bromo-, iodo), aminoalkyls, cyanoalkyls and arylalkyls, wherein the aryl moiety may be further substituted (e. g. lower alkyl and alkoxy, halogeno, hydroxy, cyano, amino, carboxy, carbonamido), on the one hand, and e. g. arylalkoxy (aryl substituted as mentioned above), on the other hand.

The cycloalkyl radicals may contain 5 to 10 ring carbon atoms, preferred are the C5-C7 species, viz. cyclopentyl, cyclohexyl, and cycoheptyl, cycohexyl being mostly preferred.

Possible substituents may be lower alkyl radicals, preferably methy and ethyl.

The aryl radicals may contain e. g. 6 to 10 cabon atoms, preferably comprising phenyl or naphthyl, optionally substituted by hydroxy, halogeno (fluoro-, chloro-, bromo-, iodo), amino, cyano, carboxy, carbonamido, or sulfo and sulfonamido.

The heteroaryl radicals preferably contain 5 to 10 ring atoms, comprising one or more, e. g. 1 to 3, nitrogen, oxygen or sulfur atoms. Examples may be imidazolyl, oxazolyl, thiazolyl, thienyl, pyrrolyl, pyrazolyl, triazolyl, pyridinyl, pyridazinyl, pyrimidyl, triazinyl, benzimidazolyl, benzoxazolyl and quinoxalinyl, including isomeric forms. With regard to the monocyclic radicals, those of 5 or 6 ring atoms are preferred.

Substituents may be selected from e. g. hydroxyl, halogen, amino and substituted amino, cyano, carboxyl (including esters and amides), sulfo, sulfoamide, lower alkyl.

The allyl radical may be optionally substituted by lower alkyl, halogen or cyano.

R2 and R3 may be combined together to form a 5 to 7-membered homocyclic or heterocyclic ring, such as cyclopentane, cyclohexane or tetrahydrofurane.

R4 and R5 and R17 and R18 may be combined together to form an N-heterocyclic, 5-or 6- membered, non-aromatic or aromatic ring, such as morpholine, pyridine, pyrrol or pyrrolidine.

Preferred substituents RI-RIB are hydrogen, alkyl of 1 to 4 carbon atoms, and hydroxyalkyl or cyanoalkyl of 1 to 4 carbon atoms in the alkyl moiety.

Further, the subtituents R6, R7, Rg, R10, R12, R14, R15 and R16 are independently of one another halogen, cyano, nitro, aryloxy, alkenyl, alkenoxy, alkoxcarbonyl, aryloxycarbonyl, acyloxy, acyl (RCO-), alkylthio, arylthio, acylamino including carboxylamino (carbonamido) R-CO-NH- (R is. g. hydrogen, alkyl or phenyl) and sulfonylamino (sulfamido) R1-SO2-NH- (Ri is e. g. alkyl or phenyl), alkylsulfonyl, arylsulfonyl or thiocyano, wherein the number of carbon atoms may be up to 10; depending on the the radicals the lower limit may be 1 (alkyl) or 6 (aryl).

Any two of R6 or any two of R7 or any two of Rg or any two of Rio or any two of R12 or any two of R14 or any two of Ris or any two of Rie my be combined together to form with the rings to which they are attached, annellated ring systems such as homocyclic or heterocyclic aromatic or non-aromatic mono-or bicyclic rings. The annellated rings may contain 6 to 10 ring atoms, and preferably are 5-or 6-membered saturated or unsaturated homocyclic rings (phenylene, cyclopentylene, cyclohexylene) ; or they contain as heterocyclic rings nitrogen, oxygen and/or sulfur atoms ; examples are thienyl, furfuryl, pyrimidyl, pyridinyl, or the group -O-. CH2-O-CH2- Preferred of the further definitions given for substituents R6, R7, Rg, Rio Razz R14 R15 and R16 are (independently of one anther) halogen, preferably chloro and bromo, cyano and nitro.

The index n is an integer of 0 to 4, preferably 0 or 2, and most preferred 0; the index m is an integer of 0 to 4, preferably 0 to 2, and mostly preferred 0.

The index p is an integer of 0 to 5, preferable 0 to 3 and most preferred 0 to 2.

The index q is an integer of 0 to 4, preferably 0 to 2 and most preferred 0.

The index k is an integer of 0 to 5, preferable 0 to 3 and most preferred 0.

The index t is an integer of 1 to 20, preferably 1 to 10, even more preferably 1 to 5 and most preferred 2.

The indexes y and w are integers of 0 to 3, preferably 0 to 2.

The index z is an integer of 0 to 4, preferably 0 to 2.

Further, when an integer n, m, p, q, k, w, y and z is applied, the R groups specified within the set denoted by that integer need not be identical. For example, the notation (where n equals three may denote the substituents chloro, methyl and nitro, i. e. the three R groups represented by (R) 3 are independent of each other.

The anion Xi-is derived from resin acids as hereinafter described under the preferred embodiments for the anion X2 The anion X2 is generally derived from organic acids, such as fatty acids of 8 to 24, preferably 8 to 18, carbon atoms which are linear of branched, saturated or unsaturated and include caprylic acid (C8), pelargonic acid (Cg), capric acid (C10), lauric acid (C12), myristic acid (C14), palmitic acid (C16), stearic acid (Cis), mono-unsaturated oleic acid (Cis), di- unsaturated linoleic acid (C,8), tri-unsaturated linolenic acid (Cis), and erucic acid (C22).

The mentioned fatty acids may be unsubstituted or, furthermore, substituted, for example by hydroxy or chlorine, preferably hydroxy. Preferably, the mentioned carboxylic acids are unsubstituted.

Preferably, the fatty acids are saturated or mono-unsaturated C12-C18fatty acids.

Further acids may be 2- (2, 4- ditert.-amylphenoxy)-butyric acid; phosphoric/phosphonic acids, such as the monolauryl ester of of phosphoric acid, the dioctyl ester of phosphoric acid or dodecyphosphonic acid; sulfonic acids, such as hexadecane sulfonic acid, alkyl substituted benzene sulfonic acids, such as p-toluene sulfonic acid or p-octylbenzene-sulfonic acid; naphthalene sulfonic acid or alkyl substituted naphthalene sulfonic acids; further phenolic acids, such as 3,5-di-tert. butylsalicylic acid; others are carboxylic acids having an unsubstituted or C1-C4alkyl-substituted C5-C7cycloalkyl skeleton, for example 4- cyclohexylbutyric acid, 3-cyclohexylpropionic acid, cyclohexylacetic acid, cyclo- hexanecarboxylic acid, 4-methylcyclohexanecarboxylic acid and cyclopentanecarboxylic acid.

Preferably the anion X2-is derived from resin acids. The term'resin acid'-in the context of this invention-comprises those acidic species that are mainly derived from (cyclic) hydrocarbon resins, such as terpenes or terpene based resins, such as colophony or the abietyl family of rosin acids, including chemically modified rosins as well as di-and polymerized rosins.

Therefore, suitable examples for resin acids may be carboxylic acids based on terpenes, for example cyclic, monocyclic or bicyclic Cloterpenes, cyclic, monocyclic, bicyclic or tricyclic C15sesquiterpenes, acyclic, monocyclic or tricyclic C20diterpenes, especially tricyclic Csoditerpenes, e. g. abietic acid, dihydroabietic acid and tetrahydroabietic acid. Preferred resin acids are colophony (main component abietic acid), rosin acid and abietyl resin as well as derivatives thereof, in particular chemically modified rosin acids.

The rosin acids include e. g. gum rosin, wood rosin, talloil rosin and chemically modified species, such as halogenated, sulfonated, phosphonated or nitrated rosins; further included are disproportionated, hydrogenated, dimerised, polymerised or part-polymerised rosins; and also rosin modified esters, such as maleinized rosin, pentaerythritol rosin ester and rosin- modified phenofic resin.

The anions Xi'and Xi are not derived from inorganic acids, such as hydrochloric acid, sulfuric acid and others.

The chromophores of the cationic (basic) dyestuffs of formulae (1) to (4) are e. g. compiled as C. I. Basic Dyes in The Colour Index (C. I.), issued by the Society of Dyers and Colorists and The American Association of Textile Chemists and Colorists. Details of the dyes are disclosed there.

Representative examples are: for dyestuffs of formula (1): C. I. Basic Red 14, C. 1. Basic Violet 16 (C. I. No. 48013); for dyestuffs of formula (2): C. I. Basic Red 12 (C. I. No. 48970); for dyestuffs of formula (3): C. I. Basic Red 54; for dyestuffs of formula (4): C. I. Basic Blue 145.

Component (2) of the inventive printing ink compositions is an organic solvent, (comprising the whole range from polar to non-polar organic solvents), which may be selected from the group consisting of optionally halogenated aliphatic hydrocarbons, optionally halogenated aromatic hydrocarbons, preferably of the benzene series, dialkyl and cyclic ethers, glycol ethers, polyalkylene glycols, polyalkylene glycol ethers, alcohols (mono-and poly-hydric), esters, ketones, nitrogen containing heterocyclic compounds, solubilising ink vehicle components, and monomers (acrylate monomers), as well as mixtures thereof.

The aliphatic hydrocarbons e. g. have boiling points in the range of 75 to 400°C ; they are preferably those having a boiling point of about 75 to 180°C, though higher boiling distillates within the boiling range of 180 to 400°C are also highly applicable.

Typical examples are heptane, octane, nonane, decane and like normal paraffins, isootane and like iso-paraffins ; ligroin, petroleum spirit, and refined gasoline, 1-heptene, 1-octene, 1- nonene. Examples of the higher boiling distillates are of the range of 240 to 270°C and 280 to 350°C, respectively.

The preferred aromatic hydrocarbons are those of the benzene series, particularly unsubstituted or C1-C4-alkyl substituted benzenes, such as benzene, xylene, and preferably toluene ; and further halogenated benzenes, such as the the chlorobenzenes (mono-, di-and tri-).

As glycolethers there can be used e. g. ethylene glycol monomethyl and monoethylether, dipropylene glycol, ethyidiglycol, butyidiglycol or phenylglycol.

Typical alcohols are e. g. C1-C8 alcohols, such as the more polar ones like methanol, ethanol, n-propanol, iso-propanol, and ethoxypropanol, where ethanol is a preferred species; and also the more non-polar ones which are e. g. C4-C8 alcohols, such as n-butanol, isobutanol, sec- butanol, tert-butanol, or n-hexanol as well as the corrosponding isomers and further cyclohexanol and benzyl alcohol.

Dialkylethers are e. g. methylethylether or diethylether, examples of cyclic ethers are tetrahydrofuran and dioxan.

Representative esters are the acetates, such propyl acetate or butylacetate, and preferably ethyl acetate.

Suitable ketones are acetone, methylethyl ketone, methylisobutyl ketone, diacetonafcohol, cyclohexanone and acetophenone.

Preferred species of the halogenated aliphatic hydrocarbons are dichloromethane, trichloromethane, tetrachloromethane, trichloroethane, tetrachloroethane, trichloroethylene, tetrachloroethylene.

A nitrogen-containing heterocyclic compound is e. g. N-methyl-2-pyrrolidone or 1, 3-dimethyl- 2-imidazolidone.

Polyalkylene glycols, preferably a low molecular weight polyethylene glycol having a molecular weight of from 100 to 800, are e. g. diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol 200, polyethylene glycol 300, polyethylene glycol 400 or polyethylene glycol 600, especially having a molecular weight of from 150 to 400, or a low molecular weight polypropylene glycol, e. g. dipropylene glycol, tripropylene glycol, polypropylene glycol P 400 or polypropylene glycol P 425.

Polyalkylene glycol ethers are e. g. C1-C4alkyl ethers of a polyalkylene glycol, e. g. diethylene glycol monobutyl ether, 2- (2-methoxyethoxy) ethanol, 2- (2-ethoxyethoxy) ethanol, 2- [2- (2- methoxyethoxy) ethoxy] ethanol or 2- [2- (2-ethoxyethoxy) ethoxy] ethanol.

Glycols or thioglycols are e. g. C2-C6alkylene glycols or a thioglycols, such as ethylene glycol, propylene glycol, butylene glycol, 1, 5-pentanediol, thiodiglycol, hexylene glycol.

Polyhydric alcohols and their ethers are e. g. glycerol or 1,2, 6-hexanetriol and a C1-C4alkyl ether of such as 2-methoxyethanol or 1-methoxypropan-2-ol.

Monomers of UV-curing inks also class as solvents in this context. Typical examples are, but not exclusively, acrylate monomers, such as 1, 4-butanediolacrylate, propoxylated glycerol triacrylate and pentaerythritol triacrylate. It is also possible that ink vehicle components or excess organic acid can act as solvent to the reaction.

Preferred organic solvents (2) are those selected from the group consisting of optionally halogenated aliphatic hydrocarbons, optionally halogenated aromatic hydrocarbons, preferably of the benzene series, dialkyl ethers, glycol ethers, (non-polaripolar) alcohols, esters, ketones, solubilising ink vehicle components, monomers (acrylate monomers) and -mixtures thereof. A preferred. mixture of polar solvents comprises ethanollethylacetate (ratio 1-99: 99-1 v/v).

The organic acids which constitute component (3) of the inventive printing ink composition are those mentioned hereinbefore when defining the anion Xi"for the dyestuffs of formula (1) as such derived from resin acids. Mixtures of acids can also be used.

It is preferred that the acids used are not surfactive in nature and are perFectly compatible with the ink solvent and binders (ink vehicles).

For the printing ink compositions containing the dyestuffs of formulae (1) to (4), the acids used as component (3) may-besides the resin acids-also comprise non-resinous acids ('acidic species') selected from the group consisting of organic carboxylic acids and organic sulfonic acids of e. g. 6 to 36, preferably 6 to 24, carbon atoms, and which may be aliphatic (linear, branched, saturated, unsaturated) or aromatic species.

Halogenated organic acids or anhydrides as shown e. g. in US-A-4'605'441 are not used.

The aliphatic carboxylic acids, preferably saturated or unsaturated fatty acids of 6 to 18 carbon atoms, may be unsubstituted or, furthermore, substituted, for example by lower alkyl (e. g. 2-ethylhexanoic acid); the aromatic acids may be substituted by chlorine, lower alkyl and/or hydroxy (e. g. salicylic acid and 3,5-di-tert. butyl-salicylic acid) or may be polyacids (e. g. 1,2, 4-benzenetricarboxylic acid).

Further acids may be acid-bearing (carboxylic acid group bearing) esters and amides, including monomers, dimers, oligomers (trimers etc.) and polymers of these such as acrylic acid, polyacrylic acids, polyaspartic acid and polyhydroxystearic acid.

Preferably, the acids are aliphatic or aromatic sulfonic acids of 6 to 24 carbon atoms, such as alkyl sulfonic acids or optionally substituted benzene or naphthalene sulfonic acids.

Examples of these acids are alkyl (C6-C, 8) sulfonic acids, such as hexyl sulfonic acid, hexadecyl sulfonic acid or octadecyl sulfonic acid; alkyl (Ci-Cis) benzene sulfonic acids, such as p-toluene sulfonic acid, p-octylbenzene-sulfonic acid, p-dodecylbenzene sulfonic acid or p-octadecylbenzene sulfonic acid; and naphthalene sulfonic acid or allcyl (C1-C8) naphthalene sulfonic acids.

Further acids may be (partial esters of) phosphoric/phosphonic acids, containing e. g. 8 to 18 carbon atoms in the ester part, such as the monolauryl ester of. phosphoric acid, the dioctyl ester of phosphoric acid or dodecylphosphonic acid.

Alternatively, for printing ink compositions containing the dyestuff of formula (4), the acids used as component (3) may comprise the aliphatic or aromatic sulfonic acids mentioned hereinbefore.

Component (4) of the inventive compositions preferably relates to organic pigments which comprise, but not exclusively, such pigments as monoazo, disazo, naphthol, dioxazone, azomethine, azocondensation, metal-complex, nitro, perinone, quinoline, anthraquinone, benzimidazolone, isoindoline, isoindolinone, quinacridone, hydroxyanthraquinone, aminoanthraquinone, anthrapyrimidine, indanthrone, flavanthrone, pyranthrone, antanthrone, isoviolanthrone, diketopyrrolopyrrole, carbazole, perylene, indigo or thioindigo pigments.

Mixtures of the pigments may also be used.

Preferred are organic pigments of the following chemical classes : Monoazo, disazo, azomethine, naphthol, and metal-complex pigments (e. g. phthalocyanines).

For further details as to the organic pigments reference is made to Industrial Organic Pigments, W. Herbst, K. Hunger, 2nd edition, VCH Verlagsgesellschaft, Weinheim, 1997.

Optionally the organic pigments can be mixed with inorganic pigments which include among others titanium oxide pigments, iron oxide and hydroxide pigments, chromium oxide pigments, spinel type calcined pigments, lead chromate pigments, carbon black and Prussian Blue.

Alternatively, full replacement of organic pigments by inorganic ones is also possible.

A further object of the present invention are the sulfonates of the aliphatic or aromatic sulfonic acids, as mentioned hereinbefore, of C. 1. Basic Red 54 and C. 1. Basic Blue 145, preferably the dodecylbenzene sulfonates ; and further carboxylates, as mentioned herein before, of C. I. Basic Red 54, preferably the oleate, the 2-ethylhexanoate and carboxylates derived from said resin acids.

These salts can be prepared by reacting e. g. the carbinol precursors or the decomposable salts of. the dyestuffs with the-corresponding sulfonic or carboxylic acids in equimolecular amounts or a surplus of the acids.

The inventive printing ink compositions can be prepared by a variety of processes which are further objects of the present invention: - So called (a) dye-precursors of the cationic azo and methine dyes, including e. g. the carbinols of said dyes or salts that decompose when treated with an organic acid, such as carbonates and hydrogencarbonates (bicarbonates) of said dyes, or their mixtures, dissolved or dispersed in an organic solvent, are mixed together with (b) an organic resin acid or salt thereof, dissolved in an organic solvent, and with (c) optionally a pigment.

- Further, a process for preparing printing ink compositions containing the dyestuffs of formulae (1) or (2) which comprises mixing together (a) dye precursors of formulae (5) or (6) wherein R, to R8, m and n have the indicated meanings and A is-OR, -N (R) 2, -N (R) COR, N (R) S02R,-SR,-S (0) R,-OzCR,-N (R) CON (R) 2,-OCON (R) 2,-S02N (R) 2 or-N (R) COOR, wherein R is Ri, dissolved or dispersed in an organic solvent, with (b) an organic resin acid, dissolved in an organic solvent, and with (c) optionally a pigment.

As to the preferences of the substituents and explanations given, reference is made to those definitions provided for them for the compounds of formulae (1) and (2).

Mostly preferred as substituent A is-OH.

- When using the dye precursor of formula (6), alternatively to the addition of the organic resin acids (as component (b) ) the non-resinous acidic species mentioned hereinabove can be used too for preparing the printing ink compositions.

This process can also be used for the dye precursors of formula (5) leading to known compositions that were used in transfer ink ribbons (US 5'698'490). The use of these compositions as printing inks, however, is a further object of the present invention.

- Further a process for preparing the printing ink compositions containing the dyestuffs of formulae (3) or (4) which comprises mixing together (a) salts of the dyestuffs of the formulae (3) or (4), which decompose when treated with an organic acid, dissolved or dispersed in an organic solvent, with (b) an organic acid, dissolved in an organic solvent, and with (c) optionally a pigment.

Suitable dyestuff salts that decompose are e. g. the hydrogencarbonates (bicarbonates) (HC03) and the carbonates (Co32-).

- According to a further alternative, the preparation can be performed as follows : This process comprises mixing together (a) a dye precursor/decomposable salt of the dyestuffs of formulae (1) to (4) with (b) a solution of an organic acid, preferably a resin acid, dissolved in an organic (polar or non-polar) solvent, evaporating off the solvent (under reduced pressure) from that mixture until a dry mixture is obtained, and redissolving the dry mixture in an organic solvent (organic non-polar solvent) compatible with the desired ink medium, and with (c) optionally an (organic) pigment.

The dye precursor (a) may comprise species of formulae (5) and (6) or the carbonates/bicarbonates of the compounds of formulae (3) and (4).

The'decomposable salt'is decomposed by the treatment with an organic acid as herein- before defined.

The solvent for the solution (b) must be a solvent wherein both the starting materials (carbinol/carbonates-bicarbonates/resin acid) are sufficiently soluble to allow reaction. The organic solvent designated as preferred herein before are most suitable, in particular the ketones (acetone), dialkyethers (diethylether) and the halogenated hydrocarbons (dichloromethane, chloroform).

Further these solvents can be easily removed from the reaction mixture.

The solvents to be used in the redissolving step should be selected from those of the mentioned solvents as preferred which are known as so-called ink solvents, such as aromatic hydrocarbons (toluene), aliphatic alcohols (methanol, ethanol) and esters (ethyl acetate) or mixtures thereof.

Further, the inventive process additionally comprises mixing a so-called ink vehicle (binder), such as e. g. resins, oils, cellulosics, polyamides, polyolefinic species (derived from vinyl-or acryl-type monomers) and rosins and rosin esters, with the combined dry, or wet, or redissolved components (a), (b) and optionally (c).

These ink vehicles which are in general any known binders include as resins, e. g. long-oil-, medium-oil-or short oil-alkyd resins, phenol-modified alkyd resins, phenolic resins, rosin- modified phenolic resins, metal resinates, such as copper, zinc or magnesium resinate, petroleum resins, (cyclic) hydrocarbon resins, such as terpene or terpene-phenolic resins, resins based on acrylic, styrenes and vinyl polymers, melamine and epoxy resins, dimerised and polymerized rosins, rosin modified maleic, fumaric and phenolic resins, epoxide and maleic resins; as oils, e. g. distillate and vegetable oils ; as cellulosics e. g. nitrocellulose, cellulose acetate propionate; polyamides ; as polyolefinic species e. g. polyvinylbutyral, polyvinylalcohol, polyvinylacetate, acrylic, propionated acrylic, polyvinylchloride, polyvinyidichloride, chlorinated polyolefine, Alternatively, the inventive process may be carried out by dry mixing components (a), the organic (resin) acid (mentioned in component (b) ), and optionally (c), and then co-dissolving this mixture in an organic solvent, preferably a non-polar organic solvent as hereinbefore defined.

The wet blend (co-dissolved mixture-as solution or in concentrated form) is a further object of the present invention.

The dry mixture of components (a), the organic (resin) acid, and optionally (c) used according to this alternative is a further object of the present invention.

Altematively, the inventive process comprises dry mixing components (a), the organic (resin) acid, and optionally (c), and an ink vehicle, and then co-dissolving this mixture in an organic solvent, preferably a non-polar organic solvent.

The dry mixture of components (a), the organic (resin) acid, and optionally (c), and an ink vehicle used according to this alternative is a further object of the present invention.

The wet blend (co-dissolved mixture-as solution or in concentrated form) is a further object of the present invention.

As a further alternative, the inventive process comprises incorporating components (a), the organic (resin) acid, and optionally (c) separately or as dry mix into preformed ink vehicles.

This process can be carried out by extruding the components (a), the organic (resin) acid, and optionally (c) separately or as dry mix into high solids dispersions, solutions or pastes of the ink vehicle.

The extrusion products obtained according to this process are a further object of the present invention.

The organic/inorganic pigments (c) are those as defined hereinbefore.

Processing can also be carried out by predissolving the organic resin acid in the molten ink vehicle or an ink vehicle component by application of shear and/or heat if necessary. Into this medium the carbinol precursor is dissolved by the application of shear and/or heat if necessary. Alternatively, both carbinol precursor and organic resin acid can be co-dissolved into the ink vehicle in one step.

Further, the inventive process is carried out, wherein components (b) and (c) together constitute a resinated pigment.

The essential components and the optional components can be mixed by any known method using a ball mill, sand mill, bead mill, attritor, continuous horizontal medium dispersing machine, two-roll mill, three-roll mill, pressure kneader, or extruder; further by manual or mechanical shaking, or by low or high shear stirring.

The conventional process for preparing a pigment based printing ink composition may be carried out in two steps : (I) The dissolving of the ink vehicle in the organic solvent.

(II) The dispersion of the pigment within the dissolved ink vehicle.

Step (11) normally requires a far higher level of shear than step ()) and results in the generation of heat.

It has now been found that preparing the inks according to the present invention is extremely flexible which can be shown by the following manufacturing methods all of which produce identical inks: - The organic (resin) acid is fully dissolved in the organic solvent, followed by the precursor (carbinol). The dye solution thus produced is added to a previously prepared ink-vehicle solution.

- The organic (resin) acid and the precursor (carbinol) are dry mixed together and then codissolved in the organic solvent (non-polar organic solvent). The dye solution thus produced is added to a previously prepared ink-vehicle/toluene solution.

- The organic (resin acid), the precursor (carbinol) and the ink-vehicle resin are dry mixed together and then co-dissolved in the organic solvent (non-polar organic solvent).

In all three cases the level of shear required is similar to that necessary for normal dissolving of ink vehicle resins and far less than that required for pigment dispersion. Due to the lower shear, the generation of heat within the inks is much reduced.

It is therefore possible to produce a finished coloured ink within the same timescale and using similar shear to that normally required for the simple dissolving of the ink vehicle resin.

Due to the simplicity of reaction, many processing possibilities are now open. The production of a coloured ink can now be carried out. on any equipment capable of generating low levels of shear. The traditional high shear approach to pigment dispersion is not required though the possibility of carrying out both in tandem is included.

Combination of the precursor (carbinol) with the resin acid can be carried out in an extruder with a suitable carrier system. This carrier system may be a solvent or a concentrate of a suitable ink vehicle. Reaction of the precursor (carbinol) may be achieved during the extrusion process though this is not essential as this can occur during the later dispersion of the concentrate within the ink solvent.

The precursor (carbinol) approach to colouration can be used in conjunction with traditional pigment methodology. As such, further possibilities for both ink and pigment processing are opened.

In general, many conventional solvent based liquid inks do not contain high levels of abietyl resins (resin acid) as part of their compositions. Such resins are commonly used in pigments destined for use in distillate or vegetable oil based offset lithographic inks. In addition to improving the performance of the pigment within the ink system further advantages are also gained. The abietyl resin treatments act to reduce aggregation of the pigment during production and drying. Abietyl resin containing pigments in general can be produced more quickly and more reproducibly while also giving products of much reduced aggregation. As a result the dispersibility of the product and the final performance are often superior.

Conventionally, many solvent based liquid inks, e. g. toluene based publication gravure inks, have not utilised abietyl resin containing pigments as the solution of this material into the ink vehicle causes increased viscosity. However, as abietyl resins are acidic in nature, the possibility now exists to use this material as a converting agent for carbinol dye pre-cursors.

Thus the pigment can be considered as a carrier for the carbinol-converting agent. The carbinol can also be considered as an agent that reduces the traditional problems of using resinated pigments in toluene systems. The high colour strength of the resulting dyestuff allows the use of a lower pigmentation level thus reducing viscosity. The possibility also exists for improved gloss thus allowing an equivalent reduction in binder level.

The inventive compositions may be employed in any amount effective for the intended purpose. In general good results have been obtained with compositions which comprises by weight 0. 1--50-% of component (1), 1-95%, preferably 5-95% % of component (2), 0. 1-75 %, preferably 0.1 to 50%, of component (3), and 0-50 % of component (4).

Preferably the concentrations may be: 15-40 % of component (1), 40-60 % of component (2), 20-50 % of component (3), and 0-50 % of component (4).

The compositions may be generally embodied in the following two forms: (A) A composition containing components (1) to (3) but no pigment-this composition can be used itself as printing ink, e. g. gravure printing or flexographic printing ink (whole colourant composition).

(B) A composition containing components (1) to (4) wherein components (1) to (3) serve as toning agents for the shading, tinting and brightening of predominatly pigment (4) based printing inks (partial colourant composition).

The organic (resin) acid of component (3) is the excess acidic component from the reaction with the (carbinol precursor). Though most experimental work has required high levels of the acidic component to push the reaction forward. It is possible that a 1: 1 molar reaction with the carbinol can be done.

Thus component (3) may be present at 0 %, i. e. there is no excess of acid present in the ink compositions; in this case e. g. the ink vehicle (as hereinbefore defined) can be used as component (3). Alternatively, there there can be a certain excess that can be defined as above about 0. 1%. It has also proved possible that the excess acidic component is used to make up the majority of the binder resin composition (e. g. gravure binder resins where the binder resins are often derivatives of resin acids, such as metal resinate salts) and therefore can become an amount of up to 75%, preferably 50%.

The excess amount of component (3) can be defined, therefore, as being 0.1 to 75%, preferably 0.1 to 50%.

Furthermore, the printing inks may in addition comprise customary additives known to those skilled in the art.

Typical additives include drying enhancers, drying inhibitors, non-coloured extenders, fillers, opacifiers, antioxidants, waxes, oils, surfactants, rheology modifiers, wetting agents, dispersion stabilizers, strike-through inhibitors and anti-foaming agents; further adherence promoters, cross-linking agents, plasticisers, photoinitiators, deodourants, laking agents and cheating agents.

Such additives. are usually used in small amountsoffrom Oto 5% by weight, particularly from.

0 to 2% by weight, and preferably from 0.01 to 1 % by weight, based on the total weight of the printing ink (gravure printing ink and others) composition.

The inventive printing ink compositions can be used in the corresponding processes for the printing of flat substrates such as publication and packaging gravure, lithographic, letterpress and flexographic printing. These processes are further objects of the present invention.

These processes are used, for example but not exclusively, for the printing of magazines, newspapers, magazine supplements, catalogs, posters, packaging materials, food wrappings and containers, paper, foil and plastic films.

The present invention is hereafter further described with reference to particular examples thereof. It will be appreciated that these examples are presented for illustrative purposes and should not be construed as a limitation on the scope of the invention as herein described.

In the following examples, quantities are expressed as parts by weight or percent by weight, if not otherwise indicated. The temperatures are indicated in degrees centigrade.

All examples are carried out at room temperature. Reaction time is defined as the time necessary to achieve full solution which indicates full reaction of the dye precursor and the organic (resin) acid. Ingeneral, this reaction timeis between 2 and 20 minutes, though can vary depending on the level of agitation applied.

Examples: Example 1 10g C. I. Basic Red 54 bicarbonate (hydrogencarbonate) salt is combined with 10g dodecylbenzenesulfonic acid in 10g ethanol. 70g of a 31% solids nitrocellulose medium, with the remainder being a roughly 5: 1 (v/v) blend of ethanol and ethyl acetate, is then added followed by glass beads then mechanically shaken. A strong deep dark red ink is thus produced.

Example 2 1g oleic acid is combined with 0.5g C. I. Basic Red 54 bicarbonate salt, stirred and warmed gently. Toluene is then added to reveal full solution of a strong deep red colouration.

Example 3 2.25g 2-ethylhexanoic acid and 1. Og C. l. Basic Red 54 bicarbonate salt are mixed and warmed gently. Once full solution is obtained, 5g of a lithographic heat-set ink medium is added with stirring to give a deep red ink.

Example 4 1. Og dodecylbenzene sulfonate and 1. 0g C. 1. Basic Red 54 bicarbonate salt are mixed in 20mi ethanol and boiled until full evaporation is achieved. 0.48g of the resulting 50% dye mixture is combined with 1. 52g of a lithographic heat-set varnish, stored for 30 minutes at 70°C then dispersed by Muller glass plate dispersion apparatus (2 series of 25 revolutions with no added weights).

The resulting ink shows equal strength to a conventional pigment ink, based on a lithographic C. I. Pigment Red 57: 1 composition, which is prepared by combining 0.24g pigment with 1.76g varnish using 5 series of 75 revolutions with 2kg weights and no heat treatment.

Furthermore the dye ink displays improved gloss and transparency.

When repeating Example 4 by using C. I. Basic Blue 145 bicarbonate, the same good results are obtained.

Example 5 5g C. I. Basic Red 12 carbinol is combined with 5g dodecylbenzenesulfonic acid in 5g ethanol. 35g of a 31 % solids nitrocellulose medium, with the remainder being a roughly 5: 1 blend of ethanol and ethyl acetate, is then added followed by glass beads then mechanically shaken. A strong deep blue shade red ink is thus produced.

Example 6 2. 59 polymerised rosin is dissolved in 10moi ethyl acetate followed by 1. 0g C. I. Basic Red 12 carbinol. The mixture is shaken till full solution is achieved then 5g of a 31% solids nitrocellulose medium, with the remainder being a roughly 5 : 1 blend of ethanol and ethyl acetate, is added. Printing this ink reveals strong blue shade red colouration with high gloss and transparency.

Example 7 10g of C. 1. Basic Red 12 carbinol and 20g tall oil rosin are combined in 28.5g ethanol and 41.5g of a 24% solids commercial nitrocellulose ink vehicle (with the remainder being ethanol). The resulting mixture is shaken for 45 minutes on a mechanical shaker. The resulting ink displays strong red colouration.

Massive improvements in gloss and transparency are achieved over an ink prepared from 10g of a commercial C. I. Pigment Red 57: 1 composition, in place of the carbinol and tall oil rosin, dispersed by the aid of glass beads for an equivalent time on the mechanical shaker.

A 50/50 blend of the above pigment and dye inks shows equal colour strength to pure pigment plus great improvements in gloss, transparency and purity plus also reduced dichroism.

Furthermore, 70: 30 ratios of pigment ink to dye ink show a 5% strength benefit over pigment alone.

Example 8 2.5g tall oil rosin is dissolved in 10moi toluene followed by 1. 0g C. I. Basic Red 12 carbinol.

The mixture is shaken till full solution is achieved then 5g of a 50% solids metal resinate medium, with the remainder being toluene, is added. Printing this ink reveals strong blue shade red colouration with high gloss and transparency.

Example 9 1. 0g dodecylbenzene sulfonate and 1. 0g C. I. Basic Red 12 carbinol are mixed in 20mi toluene and boiled until full evaporation is achieved. 0.48g of the resulting 50% dye mixture is combined with 1.52g of a lithographic heat-set varnish, stored for 30 minutes at 70°C then dispersed by Muller glass plate dispersion apparatus (2 series of 25 revolutions with no added weights).

The resulting ink shows 10% higher strength than a conventional pigment ink, based on a lithographic C. I. Pigment Red 57: 1 composition, which is prepared by combining 0.24g pigment with 1.76g varnish using 5 series of 75 revolutions with 2 kg weights and no heat treatment. Furthermore the dye ink displays improved gloss, transparency and dispersibility Example 10 0.12g of C. I. Basic Red 14 carbinol and 0.12g dodecylbenzenesulfonic acid are dissolved in 1. 2g ethyl acetate. 1. Og of a 24% solids commercial nitrocellulose ink vehicle (with the remainder being ethanol) is then added and shaken giving a full deep red solution. The resulting ink gives deep, strong, glossy and transparent red colouration on printing.

Example 11 0.5g of C. I. Basic Red 14 carbinol and 0.5g dodecylbenzenesulfonic acid are dissolved in 4.85g ethanol. 4.15g of a 24% solids commercial nitrocellulose ink vehicle (with the remainder being ethanol) is then added followed by 1.5g ethyl acetate and shaken giving a full deep red solution. The resulting ink gives deep, strong, glossy and transparent red colouration on printing.

Example 12 0. 5g of C. l. Basic Red 14 carbinol and 0.5g dodecylbenzenesulfonic acid are dissolved in 4.85g ethyl acetate. 4.15g of a 24% solids commercial nitrocellulose ink vehicle (with the remainder being ethanol) is then added followed and shaken giving a full deep red solution.

The resulting ink gives deep, strong, glossy and transparent red colouration on printing.

Example 13 0.5g of C. I. Basic Red 14 carbinol and 1. Og dodecylbenzenesulfonic acid are dissolved in 4.85g toluene. 2. 0g of a 50% solids metal resinate medium, with the remainder being toluene, is then added and shaken giving a full deep red solution. The resulting ink gives deep, strong, glossy and transparent red colouration on printing.

Example 14 0.12g of C. I. Basic Red 14 carbinol and 0.12g dodecylbenzenesulfonic acid are dissolved in 1.2g toluene. 0.5g of a 50% solids metal resinate medium, with the remainder being toluene, is then added and shaken giving a full deep red solution. The resulting ink gives deep, strong, glossy and transparent red colouration on printing.

Example 15 0.12g of C. I. Basic Violet 16 carbinol and 0.12g dodecylbenzenesulfonic acid are co- dissolved in 1. 2g ethyl acetate followed by 1. Og of a 24% solids commercial nitrocellulose ink vehicle (with the remainder being ethanol) with shaking giving a full deep violet solution. The resulting ink gives deep, strong, glossy and transparent violet colouration on printing.

Example 16 0.12g of C. 1. Basic Violet 16 carbinol and 0.12g dodecylbenzenesulfonic acid are co- dissolved in 1.2g toluene followed by 0.5g of a 50% solids commercial metal resinate ink vehicle (with the remainder being toluene) with shaking giving a full deep violet solution. The resulting ink gives deep, strong, glossy and transparent violet colouration on printing.

Example 17 2. 0g of C. I. Basic Red 54 bicarbonate and 2. 0g dodecylbenzenesulfonic acid are combined with 10. 0g of a 24% solids nitrocellulose varnish (with the remainder being ethanol) in 10ml ethyl acetate and mechanically shaken for 4 minutes to produce a strong deep red ink.

Example 18 1.5g dodecylbenzenesulfonic acid and 1.5g of C. I. Basic Blue 145 carbonate are combined in 19.8 g ethanol, 21.7g ethyl acetate and 3.0 diacetonealcohol together with 52.5g of a 20% solids nitrocellulose varnish (with the remainder being a 3.5 : 1 blend of ethanol and ethyl acetate) and mechanically shaken for 45 minutes in the presence of glass beads. The resulting ink shows high colour strength, gloss and transparency.

Example 19 0.25g of C. I. Basic Blue 145 carbonate is combined with 0.5g dodecylbenzenesulfonic acid and 1g toluene in a 50% solids metal resinate ink medium (with the remainder being toluene) and shaken by hand. The resulting ink shows high colour strength gloss and transparency.

Example 20 0. 25g of C. I. Basic Blue 145 carbonate is combined with 0.25g dodecylbenzenesulfonic acid and 2. 1g of a 24% solids nitrocellulose varnish (with the remainder being ethanol) in a solvent blend of 2.4g ethanol, 1g ethyl acetate and 0.3g diacetonealcohol and shaken by hand. The resulting ink shows high colour strength, gloss and transparency.

Example 21 0.25g of C. I. Basic Blue 145 carbonate is combined with 0.25g dodecylbenzenesulfonic acid and 2. 1g of a 24% solids nitrocellulose varnish (with the remainder being ethanol) in 2.4g ethyl acetate and shaken by hand. The resulting ink shows high colour strength, gloss and transparency.

Example 22 0. 25g of C. l. Basic Blue 145 carbonate is combined with 0.5g polymerised rosin and 2. 1g of a 24% solids nitrocellulose varnish (with the remainder being ethanol) in 2. 4g ethyl acetate and shaken by hand to produce a strong blue ink.

Example 23 0.25g of C. I. Basic Blue 145 carbonate is combined with 0. 25g salicylic acid and 2. 1g of a 24% solids nitrocellulose varnish (with the remainder being ethanol) in 2.4g ethyl acetate and shaken by hand to produce a strong blue ink.

Example 24 0.25g of C. I. Basic Blue 145 carbonate is combined with 0.25g dodecylbenzenesulfonic acid and 2. 1g of a 24% solids nitrocellulose varnish (with the remainder being ethanol) in 2. 4g ethyl acetate and shaken by hand producing a strong blue ink.

Example 25 0.25g of C. I. Basic Blue 145 carbonate is combined with 0.5g hydrogenated wood rosin and 2. 1 g of a 24% solids nitrocellulose varnish (with the remainder being ethanol) in a solvent blend of 2.4g ethanol, 1g ethyl acetate and 0. 3g diacetonealcohol and shaken by hand to produce a strong blue ink.

Example 26 0. 25g of C. l. Basic Blue 145 carbonate is combined with 0.25g salicylic acid and 2. 1g of a 24% solids nitrocellulose varnish (with the remainder being ethanol) in a solvent blend of 2. 4g ethanol, 1g ethyl acetate and 0.3g diacetonealcohol and shaken by hand to produce a strong blue ink.

Example 27 0.25g of C. I. Basic Blue 145 carbonate is combined with 0.25g para-toluenesulfonic acid and 2. 1g of a 24% solids nitrocellulose varnish (with the remainder being ethanol) in a solvent blend of 2.4g ethanol, 1g ethyl acetate and 0.3g diacetonealcohol and shaken by hand to produce a strong blue ink.

Example 28 (dodecylbenzene sulfonate of C. I. Basic Red 54) 0. 50g Cl. Basic Red 54 bicarbonate is combined with 0. 53g dodecylbenzenesulfonic acid in 20ml acetone and shaken till full solution is achieved. The solvent is slowly evaporated by heating revealing a dark red product.

Analysis by paper chromatography (Whatman No. 42 paper and a 60/40 acetone/hexane solvent system) reveals a coloured spot at a retention factor of 0.25 which is not present in the starting materials.

Example 29 (dodecylbenzene sulfonate of C. I. Basic Blue 145) 0.50g C. I. Basic Blue 145 carbonate is combined with 0. 54g dodecylbenzenesulfonic acid in 20moi acetone and shaken till full solution is achieved. The solvent is slowly evaporated by heating revealing a dark blue product.

Analysis by paper chromatography (Whatman No. 42 paper and a 60/40 acetone/hexane solvent system) reveals a coloured spot at a retention factor of 0.40 which is not present in the starting materials.

Example 30 (p-toluene sulfonate of C. I. Basic Red 54) 0.50g C. I. Basic Red 54 bicarbonate is combined with 0.50g para-toluenesulfonic acid monohydrate in 20ml acetone and shaken till solution is achieved. Analysis by paper chromatography (Fisher General Purpose Schools Grade paper and a 60/40 acetone/hexane solvent system) reveals a coloured spot at a retention factor of 0.35 which is not present in the starting materials.

Example 31 (p-toluene sulfonate of C. I. Basic Blue 145) 0.50g C. f. Basic Blue 145 carbonate is combined with 0.50g para-toluenesulfonic acid monohydrate in 20moi acetone and shaken till'solution is achieved. Analysis by paper chromatography (Fisher General Purpose Schools Grade paper and a 60/40 acetone/hexane solvent system) reveals a coloured spot at a retention factor of 0.21 which is not present in the starting materials.