FIELD OF THE INVENTION:
The present invention provides a water base printing ink composition for gravure and flexographic printing.
BACKGROUND OF THE INVENTION:
CN106928771B discloses a kind of water-based flexographic ink for printing cigarette with cork paper, is made up of modified acrylic acid emulsion, colour stuffing, wetting dispersing agent, transfer agent, defoamer, deionized water, cosolvent raw material. Modified acrylic acid emulsion uses the novel acrylic emulsion containing esters of acrylic acid.
US2009297796A1 discloses a water-based screen printing ink composition which can be used for flexo or gravure printing includes an acrylic or urethane-acrylic copolymer emulsion, a crosslinker, a pigment selected from the group consisting of luminescent pigments, magnetic pigments, optical effect pigments, optically variable pigments, and a catalyst. The crosslinker has at least two different chemical functionalities within the same molecule, a first of which forms a covalent link with the polymer prior to printing and a second of which effects crosslinking of the polymer to cure the printed ink.
US7381758B2 discloses an ink composition comprising passivated optically variable pigment and a binder system which comprises an acrylic or urethane acrylic copolymer emulsion, a crosslinker, optionally a catalyst and optionally further additives. The acrylic or urethane acrylic copolymer emulsions are selected in such a way that the emulsion is alkali soluble.
US2019085191A1 discloses water-based thermoformable printing inks and coatings, which comprise one or more acrylic emulsions, one or more styrene acrylic emulsions, an adhesion promoter, and water.
US2019054760A1 discloses an ink composition for a decorative member, comprising an acrylic emulsion, a metal salt, and organic particles or inorganic particles.
US2019048215A1 discloses a self-crosslinking acrylic polymer, a coalescent and a silicone emulsion wherein the self-crosslinking acrylic polymer has a glass transition temperature of greater than 25° C.

Existing water-base inks takes long time to dry, which resulted in blocking of the print rolls.
Also the water base inks available in the industry show poor adhesion to metallised paper and/or foil paper substrates, and in order to overcome the adhesion issue, the ink requires addition of two component additives which not only affects the stability of the ink, but also makes the ink expensive.
In particular consumption of the press return water base inks becomes impossible or difficult; and also the presently available water base inks are not well compatible with UV / LED gloss and matt coatings.
OBJECTS OF THE INVENTION:
The principal objective of the present invention is to provide a water base printing ink composition for gravure and flexographic printing, which has a quick drying rate.
Another objective of the present invention is to provide a water base printing ink composition for gravure and flexographic printing, which exhibits excellent adhesion to metallised paper and/or foil paper substrates without adversely affecting the stability of the ink composition and the cost of production.
A further objective of the present invention is to provide a water base printing ink composition for gravure and flexographic printing, wherein the press return inks can be effectively consumed, hence reducing wastage.
Yet another objective of the present invention is to provide a water base printing ink composition for gravure and flexographic printing, which is well compatible with UV / LED gloss and matt coatings.
SUMMARY OF THE INVENTION:
The present invention relates to a water base printing ink composition for gravure and flexographic printing and method of preparation thereof. The water base printing ink composition for gravure and flexographic printing comprising:
a. 30% to 40% by weight of a component A,
b. 20% to 30% by weight of a component B,
c. 10% to 15% by weight of an additive,

d. 2% to 10% by weight of an Ink-solvent; and
e. 20% to 40% by weight of demineralised (DM) water,
wherein, the component A comprises of about 20% to 45% by weight a glycol ether free acrylic resin having a weight average molecular weight of about 8000 to 10000, about 10% to 40% by weight of a colourant, about 1% to 5% by weight of additives, about 2% to 10% by weight of a component-A-solvent; and about 20% to 45% by weight of demineralised (DM) water,
wherein, the component B comprising of an acrylate emulsion, a carboxylated acrylate emulsion, a methacrylate emulsion, a carboxylated methacrylate emulsion, a styrene-acrylate copolymer emulsion, or a combination thereof.
DETAILED DESCRIPTION OF THE INVENTION:
The preferred embodiments of the present invention will be described in detail with the following disclosure and examples. The foregoing general description and the following detailed description are provided to illustrate only some embodiments of the present invention and not to limit the scope of the present invention. The invention is capable of other embodiments and can be carried out or practiced in various other ways.
Unless otherwise specified, all the technical and scientific terms used herein have the same meaning as is generally understood by a person skilled in the art pertaining to the present invention. All the patents published patent applications referred to throughout the entire disclosure herein, unless specified otherwise, are incorporated by reference in their entirety.
It is to be understood that the ranges provided herein include the stated range and any value or sub-range within the stated range. For example, a range from greater than 0 % by weight to about 25 % by weight should be interpreted to include not only the explicitly recited limits of greater than 0 % by weight to about 25 % by weight, but also to include individual values, such as 0.05 % by weight, 0.9 % by weight, 7 % by weight, 21 % by weight, etc., and sub-ranges, such as from about 1 % by weight to about 24 % by weight, from about 5 % by weight to about 20 % by weight, etc. Furthermore, when "about" is utilized to describe a value, this is meant to encompass minor variations (up to +/-10%) from the stated value.

Reference throughout this specification to "one embodiment," "an embodiment," "one example," or "an example" means that a particular feature, structure, or characteristic described in connection with the embodiment or example is included in at least one embodiment of the present disclosure. Thus, appearances of the phrases "in one embodiment," "in an embodiment," "one example," or "an example" in various places throughout this specification are not necessarily all referring to the same embodiment or example. Furthermore, the particular features, structures, or characteristics may be combined in any suitable combinations and/or sub-combinations in one or more embodiments or examples. In addition, it should be appreciated that if any figures are provided herewith, they are for explanation purposes to persons ordinarily skilled in the art and that the drawings of them are not necessarily drawn to scale.
In this specification, certain aspects of one embodiment include process steps and/or operations and/or instructions described herein for illustrative purposes in a particular order and/or grouping. However, the particular order and/or grouping shown and discussed herein are illustrative only and not limiting. Those of skill in the art will recognise that other orders and/or grouping of the process steps and/or operations and/or instructions are possible and, in some embodiments, one or more of the process steps and/or operations and/or instructions discussed above can be combined and/or deleted. In addition, portions of one or more of the process steps and/or operations and/or instructions can be re-grouped as portions of one or more other of the process steps and/or operations and/or instructions discussed herein. Consequently, the particular order and/or grouping of the process steps and/or operations and/or instructions discussed herein do not limit the scope of the disclosure.
The present invention relates to a water base printing ink composition for gravure and flexographic printing and method of preparation thereof. The water base printing ink composition for gravure and flexographic printing comprising:
a. 30% to 40% by weight of a component A,
b. 20% to 30% by weight of a component B,
c. 10% to 15% by weight of an additive,
d. 2% to 10% by weight of an Ink-solvent; and
e. 20% to 40% by weight of demineralised (DM) water,
wherein, the component A comprises of about 20% to 45% by weight a glycol ether free acrylic resin having a weight average molecular weight of about 8000 to 10000, about 10% to 40% by weight of a colourant, about 1% to 5% by weight of additives,

about 2% to 10% by weight of a component-A-solvent; and about 20% to 45% by weight of demineralised (DM) water,
wherein, the component B comprising of an acrylate emulsion, a carboxylated acrylate emulsion, a methacrylate emulsion, a carboxylated methacrylate emulsion, a styrene-acrylate copolymer emulsion, or a combination thereof.
Component A
The Component A in the water base printing ink composition of the present invention is a glycol ether free acrylic resin having a weight average molecular weight of about 8000 to 10000, preferably a weight average molecular weight of about 8500 to 9000.
In another aspect of the present invention, the glycol ether free acrylic resin having a weight average molecular weight of about 8000 to 10000 may be mixed with water and ammonia to maintain pH around 8.5.
The glycol ether free acrylic resin of the present invention is 30-35% solution of Joncryl 678 from BASF, with water and ammonia to maintain pH around 8.5.
Component B
The component B in the water base printing ink composition is acrylate emulsion, a carboxylated acrylate emulsion, a methacrylate emulsion, a carboxylated methacrylate emulsion, a styrene-acrylate copolymer emulsion, or a combination thereof.
The acrylate emulsion, carboxylated acrylate emulsion, methacrylate emulsion, carboxylated methacrylate emulsion, styrene-acrylate copolymer emulsion can be selected from Induprint PAC grades and Induprint SE grades from Indulor Chemie GmbH, and Joncryl grades from BASF.
The solid content of the acrylate, carboxylated acrylate, methacrylate, carboxylated methacrylate, and styrene acrylic emulsions are in the range of 40-50%. These acrylate, carboxylated acrylate, methacrylate, carboxylated methacrylate, and styrene-acrylate copolymer emulsions are selected in such a way that the total emulsion content will be in the range of 20-30 weight% in the final ink formulation. Tg, acid value and pH of the emulsions play an important role towards getting the final ink properties, if the Tg is higher, the blocking resistance will be good, but it will negatively impact the adhesion properties. About 50-55% of the total emulsions has a Tg >100 and others are <100. The pH of about 50-55% of the emulsions is in the

range of 3 to 5.5, and others are in the range of 8 to 9.5. The acid values of the emulsions are selected in such a way that 35-40% of the total emulsions has an acid value of <75 KOH/mg and others have acid value >130 KOH/mg.
Com ponent- A-so I vent
The component-A-solvent in the water base printing ink composition is selected from ethanol, isopropyl alcohol and mixtures thereof, preferably isopropyl alcohol.
Ink-solvent
The Ink-solvent in the water base printing ink composition is selected from ethanol, isopropyl alcohol and mixtures thereof, preferably the Ink-solvent in the water base printing ink composition is isopropyl alcohol.
Colourants
In another aspect of the invention, the water base printing ink composition uses a suitable amount of colourants in the ink composition.
The solid content of the colourant in the ink composition of the present invention is present in the range of about 10% to 40% by weight of the total weight of the ink composition (wt %).
The colourant may be organic based or inorganic based for example, azo compounds (monoazo, di-azo, p-Naphthol, Naphthol AS salt type azo pigment lakes, benzimidazolone, di-azo condensation, isoindolinone, isoindoline), and polycyclic (phthalocyanine, quinacridone, perylene, perinone, diketopyrrolo pyrrole, thioindigo, anthraquinone, indanthrone, anthrapyrimidine, flavanthrone, pyranthrone, anthanthrone, dioxazine, triarylcarbonium, quinophthalone) pigments, and mixtures of any of the foregoing. In certain embodiments, the organic material is selected from perylenes, quinacridones, phthalocyanines, isoindolines, dioxazines (that is, triphenedioxazines), 1,4-diketopyrrolopyrroles, anthrapyrimidines, anthanthrones, flavanthrones, indanthrones, perinones, pyranthrones, thioindigos, 4,4'-diamino-1,1'-dianthraquinonyl, as well as substituted derivatives thereof, and mixtures thereof.
The most common non-limiting pigments include azo dyes (for example, Solvent Yellow 14, Dispersed Yellow 23, and Metanil Yellow), anthraquinone dyes (for example, Solvent Red 111, Dispersed Violet 1 , Solvent Blue 56, and Solvent Orange 3), xanthene dyes (Solvent Green 4, Acid Red 52, Basic Red 1 , and Solvent Orange 63), azine dyes (for example, Jet Black), and the like.

Major usable non-limiting organic pigments include diarylide yellow AAOT (for example, Pigment Yellow 14 Cl#21095), diarylide yellow AAOA (for example, Pigment Yellow 12 Cl#21090), Phthalocyanine Blue (for example, Pigment Blue 15), lithol red (for example, Pigment Red 52:1 Cl#15860:1 ), toluidine red (for example, Pigment Red 22 Cl#12315), dioxazine violet (for example, Pigment Violet 23 Cl#51319), phthalocyanine green (for example, Pigment Green 7 Cl#74260), phthalocyanine blue (for example, Pigment Blue 15 Cl#74160), naphthoic acid red (for example, Pigment Red 48:2 Cl# 15865:2).
Examples of Inorganic pigments include titanium dioxide (for example, Pigment White 6 Cl#77891), carbon black (for example, Pigment Black 7 Cl#77266), iron oxides (for example, red, yellow, and brown), ferric oxide black (for example, Pigment Black 1 1 Cl#77499), chromium oxide (for example, green), ferric ammonium ferrocyanide (for example, blue), and the like.
Thus, the colourant may be any conventional organic or inorganic pigments without any restriction for example Zinc Sulfide, Pigment White 6, Pigment Yellow 1 , Pigment Yellow 3, Pigment Yellow 12, Pigment Yellow 13, Pigment Yellow 14, Pigment Yellow 17, Pigment Yellow 63, Pigment Yellow 65, Pigment Yellow 73, Pigment Yellow 74, Pigment Yellow 75, Pigment Yellow 83, Pigment Yellow 97, Pigment Yellow 98, Pigment Yellow 106, Pigment Yellow 1 14, Pigment Yellow 121 , Pigment Yellow 126, Pigment Yellow 127, Pigment Yellow 136, Pigment Yellow 174, Pigment Yellow 176, Pigment Yellow 188, Pigment Orange 5, Pigment Orange 13, Pigment Orange 16, Pigment Orange 34, Pigment Red 2, Pigment Red 9, Pigment Red 14, Pigment Red 17, Pigment Red 22, Pigment Red 23, Pigment Red 37, Pigment Red 38, Pigment Red 41 , Pigment Red 42, Pigment Red 57, Pigment Red 1 12, Pigment Red 122, Pigment Red 170, Pigment Red 210, Pigment Red 238, Pigment Blue 15, Pigment Blue 15:1 , Pigment Blue 15:2, Pigment Blue 15:3, Pigment Blue 15:4, Pigment Green 7, Pigment Green 36, Pigment Violet 19, Pigment Violet 23, Pigment Black 7 and the like.
Additives:
The water base printing ink composition of the present invention may also contain the usual ink additives to adjust flow, surface tension, and gloss of printed ink. Such additives typically are polymeric dispersants, surface active agents, waxes, or a combination thereof.

The additives are present in an amount of from about 10% to 15% by weight of the total ink composition.
These additives may function as levelling agents, wetting agents, fillers, dispersants, metal chelate type adhesion promoters, defrothers (anti-foaming agent), an antistatic agent, a viscosity modifier or other additives may be added to provide a specific function.
The water base printing ink composition may contain a polymeric dispersant when the colourant is a pigment to disperse the pigment during mixing and grinding operations in the solvent. All components of the water base printing ink composition may be blended together and ground to reduce the pigment particles to the desired size distribution, typically 5 microns or less, or alternatively the pigment and the polymeric dispersant can be premixed and ground in the solvent to form a "base" which is subsequently blended with the remaining components of the gravure ink. The components in the water base printing ink composition may be mixed in a high speed mixer until a slurry consistency is reached and then passed through a media mill until the pigment is reduced to 5 microns or smaller. The wide versatility of the inks of this invention allows them to be prepared without a polymeric dispersant, but preferably they are made with a polymeric dispersant for grinding in, for example, polyvinyl butyral or blending with, for instance, a nitrocellulose base.
Other useful colourants, and additives are also possible known to the persons skilled in the art.
Examples:
The present disclosure will now be explained in further detail by the following examples. These examples are illustrative of certain embodiments of the invention without being limited to the specific examples given here.
Synthesis Examples [Preparation of Component Al
The most preferred three embodiments of the invention to prepare the Component A comprising of about 20% to 45% by weight a glycol ether free acrylic resin having a weight average molecular weight of about 8000 to 10000, about 10% to 40% by weight of a colourant, about 1% to 5% by weight of additives, about 2% to 10% by weight of a component-A-solvent; and about 20% to 45% by weight of demineralised

(DM) water are depicted below as Component A1, Component A2, and Component A3, as given in examples 1 to 3 in table 1.
Table 1
* Based on the desired end colour the ink composition, other colourants or a mixture of colourants are used.
Preparation of the Ink composition
The most preferred six embodiments of the invention to prepare the water base printing ink composition for gravure and flexographic printing using one of the aforementioned examples of component A, i.e. component A1, component A2, component A3 are given in examples 4 to 6 in table 2 depicted as lnk-1, lnk-2, and lnk-3; and a mixture of more than one of component A, i.e. component A1, component A2, component A3 are given in examples 7 to 9 in table 3 depicted as lnk-4 to lnk-6.
Table 2

Table 3
Printed article
Printed articles were formed by coating a treated substrate with a layer of water base printing ink compositions lnk-1 to lnk-6 provided in the examples 4 to 9 of the present invention, wherein, the water base printing ink composition layer has a thickness of about 0.1 to 3 GSM when dried.
Example 10.
In the aforesaid printed articles the treated substrate is a metallised paper film,
a layer of gloss coating was applied above the water base printing ink composition
layer,
wherein, the printing was carried out by gravure printing method.

Example 11.
Printed articles were formed by coating a treated substrate with a layer of water base
printing ink compositions lnk-1 to lnk-6 provided in the examples 4 to 9 of the present
invention,
wherein, the water base printing ink composition layer has a thickness of about 0.1 to
3 GSM thick when dried,
wherein, the treated substrate is a metallised paper film,
a layer of matt coating was applied above the water base printing ink composition
layer,
wherein, the printing was carried out by flexographic printing method.
Example 12.
Printed articles were formed by coating a treated substrate with a layer of foil wash
coating having thickness of 0.1- 0.2 GSM when dried prior to applying a layer of
water base printing ink compositions lnk-1 to lnk-6 provided in the examples 4 to 9 of
the present invention,
wherein, the water base printing ink composition layer has a thickness of about 0.1 to
3 GSM thick when dried,
wherein, the treated substrate is a foil paper film,
a layer of gloss coating was applied above the water base printing ink composition
layer,
wherein, the printing was carried out by flexographic printing method.
Example 13.
A printed article, where a treated substrate is coated with a layer of foil wash coating
having thickness of 0.1- 0.2 GSM when dried prior to applying a layer of water base
printing ink compositions lnk-1 to lnk-6 provided in the examples 4 to 9 of the present
invention,
wherein, the water base printing ink composition layer has a thickness of about 0.1 to
3 GSM thick when dried,
wherein, the treated substrate is a foil paper film,
a layer of matt coating was applied above the water base printing ink composition
layer,
wherein, the printing was carried out by gravure printing method.
However, a person skilled in the art pertaining to the present invention may optionally use either gloss or matt coating above the water base printing ink composition layer via gravure or flexographic printing method.

Product Evaluation:
The water base printing ink compositions lnk-1 to lnk-6 provided in the examples 4 to 9 were evaluated for their performance, and the evaluation results have been provided in the following Table 4.
Table 4
* Rating: 1=poor; 5=Excellent
The performance of the water base printing ink compositions lnk-1 to lnk-6 examples 4 to 9 when printed to form an article according to example 10 was evaluated for their performance, and the evaluation results have been provided in the following Table 5.
Table 5
Rating: 1=poor; 5=Excellent;

The performance of the water base printing ink compositions lnk-1 to lnk-6 when printed to form an article according to example 11 was evaluated for their performance, and the evaluation results have been provided in the following Table 6.
Table 6
* Rating: 1=poor; 5=Excellent;
The performance of the water base printing ink compositions lnk-1 to lnk-6 when printed to form an article according to example 12 was evaluated for their performance, and the evaluation results have been provided in the following Table 7.
Table 7

* Rating: 1=poor; 5=Excellent;
The performance of the water base printing ink compositions lnk-1 to lnk-6 when printed to form an article according to example 13 was evaluated for their performance, and the evaluation results have been provided in the following Table 8.
Table 8
* Rating: 1=poor; 5=Excellent;
Advantages:
The water base printing ink composition of the present invention exhibits the following advantages:
a. excellent printing drying rate,
b. excellent adhesion to metallised paper and/or foil paper substrates,
c. excellent blocking resistance,
d. excellent compatibility with UV / LED gloss and matt coatings,
e. excellent recovery and consumption of press return inks
Applications:
While various films can be printed with the water base printing ink composition of the present invention, especially metallised paper and foil paper have been shown in the examples given in this specification.
While the end use of these printed films are intended for packaging applications of items such as food, drinks, pharmaceutical and other medical products, other suitable

food packaging and non-food packaging applications can be envisaged by a person skilled in the art.
Although the present disclosure is described in terms of certain preferred embodiments and examples, other embodiments and examples will be apparent to those of ordinary skill in the art, given the benefit of this disclosure, including embodiments and examples that do not provide all of the benefits and features set forth herein, which are also within the scope of this disclosure. It is to be understood that other embodiments may be utilized, without departing from the true spirit and scope of the present invention being indicated by the following claims.

We claim:
1. A water base printing ink composition comprising:
a. 30% to 40% by weight of a component A,
b. 20% to 30% by weight of a component B,
c. 10% to 15% by weight of an additive,
d. 2% to 10% by weight of an Ink-solvent; and
e. 20% to 40% by weight of demineralised (DM) water,
wherein, the component A comprises of about 20% to 45% by weight a glycol ether free acrylic resin having a weight average molecular weight of about 8000 to 10000, about 10% to 40% by weight of a colourant, about 1% to 5% by weight of additives, about 2% to 10% by weight of a component-A-solvent; and about 20% to 45% by weight of demineralised (DM) water,
wherein, the component B includes an acrylate emulsion, a carboxylated acrylate emulsion, a methacrylate emulsion, a carboxylated methacrylate emulsion, a styrene-acrylate copolymer emulsion, or a combination thereof.
2. The water base printing ink composition according to claim 1, wherein,
about 50% to 55% of the component B has a Tg of >100 and about 45% to 50%
of the component B has a Tg of <100,
about 50% to 55% of the component B has a pH of about 3 to 5.5, and about
45% to 50% of the component B has a pH of about 8 to 9.5; and
about 35% to 40% of the component B has an acid value of <75 KOH/mg and
about 60% to 65% of the component B has an acid value of >130 KOH/mg.
3. The water base printing ink composition according to claim 1, wherein the Ink-solvent is selected from ethanol, isopropyl alcohol and mixtures thereof, preferably the Ink-solvent is isopropyl alcohol.
4. The water base printing ink composition according to claim 1, wherein the component-A-solvent is selected from ethanol, isopropyl alcohol and mixtures thereof, preferably the Ink-solvent is isopropyl alcohol.
5. The water base printing ink composition according to claim 1, wherein the colourant is selected from an organic pigment, an inorganic pigment, a dye and combinations thereof.

6. The water base printing ink composition according to claim 1, wherein the additive is selected from a polymeric dispersant, a surface active agent, a wax, or a combination thereof.
7. The water base printing ink composition according to any of the preceding claims, wherein the water base printing ink composition is adapted for gravure printing or flexographic printing.
8. A printed article, comprising:
a. a treated substrate,
b. a layer of water base printing ink composition according to claim 1 is applied
on the treated substrate,
wherein, the treated substrate is a metallised paper substrate,
c. a layer of gloss or matt coating is applied above the water base printing ink
composition layer.
9. A printed article, comprising:
a. a treated substrate,
b. a layer of water base printing ink composition according to claim 1 is applied
on the treated substrate,
wherein, the treated substrate is a foil paper substrate,
c. a layer of gloss or matt coating is applied above the water base printing ink
composition layer.
10. The printed article according to claims 9 or 10, wherein, the water base printing
ink layer is formed by gravure printing or flexographic printing, wherein, the water
base printing ink composition layer has a thickness of about 0.1 to 3 GSM thick
when dried.