Claims:
We Claim:

1. Pigment dispersion comprising
(A) 27-28% calcium carbonateextender;
(B) 8-13% water based gelly of Laponite RD clayinpigment dispersion pre-mix comprising
(i) glycols selected from propylene glycol 4-7%, triethylene glycol 4-13%;
(ii) 0.5-1% terpene oil;
(iii) 2-3% Surfactant;
adapted for stable dispersion of high pigment levels (10-11%)preferably organic pigments.

2. Pigment dispersion as claimed in claim 1 that is a stable dispersion of 10-11%organic phthalocyanine pigment green 7 and also includes stable dispersions of Pthalocyanine blue PB 15.1, 15.3, quinacridone pigment PR 122.

3. Pigment dispersion as claimed in claims 1 or 2 comprising
(A) 27-28% calcium carbonateextender pigments;
(B) 8-13% water based gelly of Laponite RD clay;
(C)10-11% pigments preferably phthalocyanine pigment green 7;
in pigment dispersion pre-mix comprising
(i) glycols selected from propylene glycol 4-7%, triethylene glycol 4-13%;
(ii) 0.5-1% terpene oil;
(iii) 2-3% Surfactant.

4. Pigment dispersion as claimed in claims 1-3 wherein said 8-13% water based gelly of Laponite RD clay involves Laponite RD powder in the levels of 0.5% to 0.65%, said dispersion comprising preservatives, pH control additives, biocide, thickeners/ rheology modifiers, mineral oil.

5. A method for manufacturing the pigment dispersion comprising the steps of

i. preparing Laponite RD jelly;
ii. provding pre-mix of water, Propylene Glycol, Triethylene glycol, surfactant, terpine liquid preferably with preservative and pH control additive to container with stator-rotor (R-S);
iii. stirring the premix of step (ii) above in high speed to obtain uniform mixture;
iv. adding pigment phthalocyaninegreen 7 (10-11%), followed by the addition of Laponite RD jelly (8-13%) of step (i) further followed by extender calcium carbonate;
v. adjusting the viscosity of the mill base;
vi. stirring followed by grinding with Dyno mill filled with zirconia beads(size of beads ~ 2 mm)by further adding Propylene glycol, triethylene glycol, mineral oil, preferably with biocide and cellulosic thickeners, and Water (to adjust to 100%) for batch completion and mixing to obtain said pigment dispersion.

6. A method for manufacturing the pigment dispersion as claimed in claim 5 wherein said

step (i) involves adding Laponite RD powder to water(5% powder),and stirring for 30-45 mins to form gel;

step (ii) comprises adding water (6-7%), Propylene Glycol(3-5%), triethyleneglycol(6-8%), emulsifier preferably AtsurfD901(2-3%), terpine oil preferably Dipentine(1%), preservative preferably TroysonS107(0.15%), LA198(0.15-0.2%) and pH control additive preferably Loramine101(0.1-0.15%) to container with stator-rotor (R-S).;

said step (vi)comprises adding propylene glycol (1-2%), triethylene glycol (4-5%), mineral oil preferably TegofoamexK3 (0.2-0.25%), preservative/ biocide preferably PaxgardAP001 (0.2%), 1:1 mixture of water and thickener preferably AcrysolDR130 (1.5-1.8%), pH control additive preferably Loramine101 (0.1-0.15%) and Water (to adjust to 100%).

Dated this the 18th Day of May, 2020 AnjanSen
ofAnjanSen&Associates
(Applicants’Agents)
IN/PA-199
, Description:Field of the Invention
The present invention relates to pigment dispersion, preferably (phthalocyanine pigment green 7) based pigment dispersion, comprising said pigments inhigh levels of (10-11%) suitably dispersed by involving clay ‘Laponite RD’(gel forming grade). The coloristics of said dispersion are at par with the dispersions prepared using existing methodsusing dispersing agents.
Background of the Invention
Phthalocyanine green (7), is a synthetic green pigment from the group of phthalocyanine pigment,a complex of copper(II) with chlorinated phthalocyanine. It is a soft green powder, which is insoluble in organic solvents, water and alkalibut slowly decomposes in strong acids. It is a bright, high intensity colour used in oil and acrylic based artist's paints, and as a colorant in inks, paints, chalks, leather, pencils, and photographs.
Due to the presence of strongly electronegative chlorine substituents, the absorption spectrum is shifted from that of the parent copper phthalocyanine. Phthalocyanine green is usually adsorbed on an aluminum hydrate base to form a deep vivid green color that is used as a substitute for viridian. Phthalocyanine green, however, imparts excellent UV resistance to polyethylene, as do some of the chrome greens. Compounds containing these pigments last longer than 6000 hours of weatherometer exposure with no loss of tensile strength [Book chapter by Liesl K. Massey, in The Effects of UV Light and Weather on Plastics and Elastomers (Second Edition), 2007- cited reference no-115].
For incorporation of Phthalocyanine green pigment into dispersion various methods have been reported.
Jing Wang et al., (Dispersion of Phthalocyanine Green G in Non-aqueous Medium Using Hyperdispersants and Application in E-Ink: Jing Wang,Ya-qingFeng,Jian-yuXie,Gang Li &Xiang-gao Li Journal of Dispersion Scienceand Technology Volume 27, 2006 - Issue 7Pages 975-981) reported dispersionof phthalocyanine green G modified with hyper-dispersants in tetrachloroethylene. Dispersibility and zeta potential of modified phthalocyanine green G in tetrachloroethylene were studied. The phthalocyanine green G particles modified with hyper-dispersants were characterized by FTIR and SEM. E-Ink containing dispersion liquid of phthalocyanine and tetrachloroethylene was prepared by coacervation, in situ polymerization, and interfacial polymerization. E-Ink prepared by coacervation and in situ polymerization had a reversible electric response.
MAURO BUCCELLA et al., (Influence of the Processing Parameters on the Dispersion and Coloration Behavior of a HalogenatedCopper Phthalocyanine-Based Masterbatch, Advances in Polymer Technology, Vol. 37, No. 3, 2018, DOI 10.1002/adv.21721) disclosed preparation of a mono-concentrated green masterbatch by adding a halogenated copper phthalocyanine color pigment to a commercial Polyamide6 matrix using different processing conditions. In particular, the effect of the extrusion number and the efficacy of the filtration operation were analyzed.Filter-Test analysis and color strength measurements demonstrated how the filtration system did not lead to an improvement in the dispersion quality of the master, and it could beeliminated from the industrial layout of the masterbatch production. On the contrary, repeated extrusions (i.e., enhancedSME involved in the production process) improved pigmentdispersion, leading to a consistent reduction in the filter pressure value (FPV) and to an improvement of the relative colorstrength (RCS). Thus it was demonstrated how the optimization of the processing parameters of the masterbatch preparation allows to markedly improve both the processability andthe coloration capability of the mono-concentrated green compounds.
WO1999045075A2 revealsan aqueous, non-settling, universal nacreous pigment dispersion that can be used in dispensing machines for the custom mixing of retail and trade sales of alkyd or solvent-thinned and water-based surface coatings employs a synthetic silicate, sodium lithium magnesium silicate, as the suspending agent. The composition contains from about 10 to about 33 parts by weight of component (a) a pearlescent pigment component and (b) a water- containing liquid component that is a carrier for said pigment componentcomprises:
(i) from about 1.0 to about 2.0 parts by weight of hydrous sodium lithium magnesium silicate; (ii) from about 1 to 50 parts by weight of water; (iii) from about 8 to about 50 parts of a glycol selected from the group consisting of ethylene glycol, diethylene glycol, polyethylene glycol and propylene glycol; and (iv) from about 1 to about 15 parts by weight of one or more surfactants.
DE60027460T2relates to an aqueous dispersion of organic pigment, which is used for coloring of building materials such as concrete, asphalt, plaster, mortar and cement mortar. More specifically, the advancement relates to aqueous dispersions, the silica as a binder, an organic pigment and dispersant contain wherein the silica binder is selected from silicate, metasilicate pentahydrate, sesquisilicate and orthosilicate wherein the organic pigment is selected from phthalocyanine green, phthalocyanine blue, Carbazole Violet, Toluidine Red, Dalamar Yellow and Watchung Red.
US10150878B2 describes apigment dispersion and a printing ink and coating employing the pigment dispersion. The pigment dispersion includes a pigment, binder and solvent and optionally, one or more additives. The pigment dispersion has a mean particle size less than about 120 nm. The printing ink or coating includes the pigment dispersion in addition to a solvent. The printing ink or coating has a solid binder to pigment ratio greater than about 1.5. The pigment can be in the form of an organic or an inorganic pigment and can include specialty pigments. Examples of pigments include, but are not limited to, carbon black, phthalocyanines (for example, phthalocyanine blue and phthalocyanine green), quinacridones and so on.
An aqueous pigment dispersion was prepared with a premix composed of the following components: 72.5% C.I. Pigment Yellow 14 press cake at 42.2% solids (474-4480 from Sun Chemical), 9.9% Joncryl® 674 resin pellets (BASF), 3.1% urea, 2.5% ammonia (28% solution), 0.2% Proxel GXL biocide (Dow), 0.1% Surfynol® DF-110D defoamer, and 29.1% water.
US8702862B2 relates to a colorant composition usable with water-based latex paint and oil-based paint, wherein the percentage of pigment volume concentration (PVC %) of the colorant composition is greater than about 80%, said colorant composition comprising:
a microcrystalline cellulose,a synthetic silicate,at least one metallic or pearlescent pigment, andat least one surfactant or dispersantwherein the microcrystalline cellulose comprises about 8% to about 10% by weight of the composition and the average pigment load is about 15% to about 40% by weight and synthetic silicate comprises about 75% by weight of the microcrystalline cellulose.
EP2392624A1 disclosesan aqueous liquid colorant composition having a volatile organic content up to 50g/l and suitable for colouring aqueous or solventborne decorative coatings and basepaints comprising
i) from 0 to 29wt% of non-volatile organic liquid having a vapour pressure up to 1.3 N/m2 at 25°C
ii) from 2 to 16wt% of stabilising agent
iii) from 4 to 70wt% of colour pigment
iv) from 0 to 8wt% of rheology modifying clay
v) from 0 to 20wt% of extender
wherein the ratio of iii)+iv)+v) : i)+ii) is from 1 to 3 and i)+ii) is no greater than 31wt%and the colour pigment comprises less than 51wt% and the sum of the rheology modifying clay iv) and the extender v) is at least 2wt%.
Rheology modifying clays are minerals comprising high aspect ratio sub-micron sized particles and which can form stable dispersions in aqueous media. The particles in such dispersions form loosely associated networks throughout the aqueous medium of the colorant thereby imparting rheology to the colorant.
US20100003409A1 relates to a printing ink for inkjet printing for improving the durability and image quality of an inkjet image comprising: a) a liquid carrier; b) ionic dye molecules with surface charge dissolved in the liquid carrier; and c) plate-like nanoparticles having parallel main surfaces, and minor edge surfaces, dispersed in the liquid carrier, with the main surfaces of the nanoparticles having a same sign of surface charge as the ionic dye molecule. Durability and image quality of an inkjet image is improved using the inventive ink, while also enabling a stable, printable formulation that does not require milling of the ink colorant.
Method of ink preparation: Slowly add Laponite RD to deionized water at 60° C., mix with high shear for 30 mins. Continue stir at room temperature overnight to form a 2% Laponite RD solution. Add 10% Direct blue 199 to the clay solution at a ratio of dye to clay of 1:1 and heat the mixture to 60° C for 30 mins. Add the rest of the addenda: 2.5% glycerol, 7.5% ethlyene glycol, 2% 2-pyrrolidinone, 0.5% Surfynol 465 and balance water to make an ink with blue dye concentration of 2.5% and labeled as Ink E-8.
WO 2006043257 A1 discloses a coating composition for in-situ coating of a surface comprises calcium carbonate, an acrylic or vinyl acetate-based binder, a thickening agent, and a rheology modifier, the calcium carbonate/acrylic binder ratio being from 5:1 to 15:1. The coating may be applied directly to a plasterboard wall or ceiling using a roller technique, and provides a high quality surface finish to which a paint may be applied directly. Thus, coating composition was obtained by mixing water (21.65), rheology modifier Laponite B (0.12), thickening agent Cellosize H 15000ypz (0.32), biocides Nipacide CFB (0.22) and Nipacide DFF (0.08), ammonium polyacrylate as a pigment dispersant (0.87), acrylate-styrene copolymer dispersion Revacryl 248 (6.5), calcium carbonate Omyacarb 5ML (69.29), pigment Tioxide TR 92 (0.89), and defoaming agent Rhodoline DF 6681 (0.08%).
Although different methods are prevalent in the literature, but most of them suffer from using high doses of clay or dispersants for the successful dispersion of the pigment. Thus methods/processes are needed for dispersing high amount of pigment with very little dispersant without compromising the quality and variety of the coloristics and shades.

Objective of the invention
Thus the basic objective of the present invention is to provide pigment dispersion, preferably phthalocyanine pigment green 7 (PG7) dispersion, by suitably dispersing said pigment at high levels of 10-11% by employing ‘Laponite RD’clay.
Another objective of the present invention is to provide for said pigment dispersion having high levels of pigment that would be dispersible involving very low levels of Laponite RD and low levels of surfactant.
Yet another objective of thepresent invention is to provide said pigment dispersion wherein the coloristics would be at par with the dispersions prepared using existing method of involving dispersing agents.
Another objective of the present invention is to provide said pigment dispersion wherein the processing parameters would be similar to the pigment dispersion processed by involving dispersing agents.
Yet another objective of the present invention is to provide said pigment dispersion, which would be used in paints as colorant providing better performance and acceptable shades.
Another objective of the present invention is to provide for said pigment dispersion by involving solid particles(such as Laponite RD, Silica nanoparticles)for preparation and stabilization of organic pigment such as PG 7 in said dispersion.
Another objective of the present invention is to provide said pigment dispersion having acceptable coloristics, viscosity, pH, accelerated stability and scrub resistance improvedby at least 30 cycles.

Summary of the invention
Thus the primary embodimentofthe present invention is directed to provide pigment dispersion comprising
(A) 27-28% calcium carbonateextender pigments;
(B) 8-13% water based gelly of Laponite RD clay in pigment dispersion pre-mix comprising
(i) glycols selected from propylene glycol 4-7%, triethylene glycol 4-13%;
(ii) 0.5-1% terpene oil;
(iii) 2-3% Surfactant;
adapted for stable dispersion of high pigment levels of (10-11%) preferably organic pigments.

Another embodiment of the present invention is directed to provide saidpigment dispersion that is a stable dispersion of 10-11% organic phthalocyanine pigment green 7.

Preferably said pigment dispersion is provided comprising
(A) 27-28% calcium carbonateextender pigments;
(B) 8-13% water based gelly of Laponite RD clay;
(C)10-11% high pigmentation based pigments preferably phthalocyanine pigment green 7;
in pigment dispersion pre-mix comprising
(i) glycols selected from propylene glycol 4-7%, triethylene glycol 4-13%;
(ii) 0.5-1% terpene oil;
(iii) 2-3% Surfactant.

More preferably, in said pigment dispersion said 8-13% water based gelly of Laponite RD clay involves Laponite RD powder in the levels of 0.5% to 0.65%, and said dispersion comprises preservatives, pH control additives, biocide, thickeners/ rheology modifiers, mineral oil.

Another embodiment of the present invention is directed to provide said pigment dispersion comprising said pigment dispersion pre-mix and organic pigments, particularly phthalocynanine pigments, more particularly phthalocyanine pigment green 7 in the levels of 10-11%.

Another embodiment of the present invention is directed to providea method for manufacturing the said pigment dispersion comprising the steps of
i. preparing Laponite RD jelly;
ii. provding pre-mix of water, Propylene Glycol, Triethylene glycol, surfactant, terpine liquid preferably with preservative and pH control additive to container with stator-rotor (R-S);
iii. stirring the premix of step (ii) above in high speed to obtain uniform mixture;
iv. adding pigment phthalocyaninegreen 7 (10-11%), followed by the addition of Laponite RD jelly (8-13%) of step (i) further followed by extender calcium carbonate;
v. adjusting the viscosity of the mill base;
vi. stirring followed by grinding with Dyno mill filled with zirconia beads(size of beads ~ 2 mm) by further adding Propylene glycol, triethylene glycol, mineral oil, preferably with biocide and anionic HASE (Hydrophobically modified Alkali Swellable Emulsion) thickener/cellulosic thickeners, and Water (to adjust to 100%) for batch completion and mixing to obtain said pigment dispersion.

Another preferred embodiment of the present invention is directed to provide said method for manufacturing the pigment dispersion wherein said
step (i) involves adding Laponite RD powder to water (5% powder),and stirring for 30-45 mins to form gel;
step (ii) comprises adding water (6-7%), Propylene Glycol(3-5%), triethyleneglycol(6-8%), emulsifier preferably AtsurfD901(2-3%), terpine oil preferably Dipentine(1%), preservative preferably TroysonS107(0.15%), LA198(0.15-0.2%) and pH control additive preferably Loramine101(0.1-0.15%) to container with stator-rotor (R-S).;

said step (vi) comprises adding propylene glycol (1-2%), triethylene glycol (4-5%), mineral oil preferably TegofoamexK3 (0.2-0.25%), preservative/ biocide preferably PaxgardAP001 (0.2%), 1:1 mixture of water and thickener preferably AcrysolDR130 (1.5-1.8%), pH control additive preferably Loramine101 (0.1-0.15%) and Water (to adjust to 100%).

Detailed description of the invention
As mentioned hereinbefore, the present invention is directed toprovide pigment dispersion, preferablyorganic pigment dispersion, more preferably phthalocyanine green pigment dispersion,involving clay plateletsand its method ofpreparation thereof. The method followed for the lab scale and scaled up at 16 to 20 times are discussed below. The clay used for the present invention is Laponite RD. LaponiteRD is a synthetic layered silicate. It is insoluble in water but hydrates and swells to give clear and colorless colloidal dispersions. At concentrations of 2% or greater in water, highly thixotropic gels are produced that are used for imparting a shear sensitive structure to a wide range of waterborne formulations. These include household and industrial surface coatings, cleansers, ceramic glazes, agrochemical, oilfield and horticultural products.
Extender, glycols, dipentene are also used in the regular process, where wetting and dispersing agents are used in place of Laponite RD gelly. Generally, high quantity of surfactants as wetting and dispersing agents are used to prepare pigment dispersions.
It is thus the surprising finding of the present invention that a pigment dipersion involving high levels of pigments, preferably phthalocyanine pigment green 7 (PG7) dispersion,could be achievedby involving Laponite RD gelly together with surfactant, wherein very low levels of Laponite RD powder of 0.5% to 0.65% and only 2-3% of surfactant was enough to wet the pigment and provide for a stable pigment dispersion.

The glycols in the pigment dispersion was found to provide better humectancy, however, the quantity for them is selective wherein below the given ranges, the humectancy is poor, and above the given ranges affects the performance properties such as scrub resistance, above the range scrub resistance will be poor by minimum 15% which is not acceptable.

Added to the abovesaid, the critical aspects of the process of the present invention of making said dispersion as stable dispersion with acceptable coloristics are the following:
it was found that acceptable coloristics cannot be obtained when Laponite RD gelly is added in pre-mix, butacceptable coloristics could only be obtained when addition of Laponite RD gelly was done after the addition of pigment in the pre-mix.
In a similar fashion,addition of Laponite RD gelly after adding the extender results in poor coloristics, foaming issue, non-appropriate flow during the stator-rotor and dyno mill pass that implies the criticality of Laponite RD gelly addition sequence to achieve a stable dispersion.
A stable dispersion should retain its floability, and coloristics such as color strength. The acceptable color strength of the as prepared pigment dispersion is 100 % ± 3 %. The color strength of reference sample is taken as 100 % wherein the reference sample is the colorants prepared with existing method which uses dispersing agentsand no Laponite RD jelly. Coloristics of experimental samples against reference are within the acceptable range. Color strength below 97% is not acceptable and termed as poor coloristics.
When Laponite RD gelly was added after the addition of extender, appropriate viscosity (flow) during stator-rotor and dyno mill passwas not obtained.
EXAMPLES

Preparation of Laponite RD jelly
5 g of Laponite RD powder was added to 100 g of water, the mixture was kept under stirring for about 30-45 min to form gel. Then it was stored in a container for further usage.
General method for the preparation of Pigment Dispersion

(a) Liquids such as water, Propylene Glycol, Triethylene glycol, Atsurf D901(alkyl aryl sulphonates), Dipentine, Troyson S107(mixture of Carbendazim and Octhilinone), LA198(modified polyether polysiloxane)and Loramine 101 (Proprietary alkanolamines) were weighed in water circulated double jacketed vessel. This premix was kept under stirring in high speed disperser to have uniform mixture. This was followed by addition of pigment green 7 (10-11%), the prepared Laponite RD jelly (8-13%) was added to above mixture and continued the stirring,and then extender calcium carbonate was added. Weight equivalent to the above mill base, zirconia beads were added as grinding media. After grinding Propylene glycol, triethylene glycol, TegofoamexK3, Paxgard AP001, AcrysolDR130, and Water (to adjust to 100%) were added to complete the batch and mixed well. Then it was filtered and stored in a container till further evaluation.

Example-1: Preparation of Pigment dispersion at lab scale

Liquids such as water (10%), Propylene Glycol (3-5%), triethylene glycol (4-6%), AtsurfD901 (2-3%), Dipentine (0.5-1%), TroysonS107 (0.15%), LA198 (0.15-0.25%) and Loramine101 (0.1-0.15%) were weighed in water circulated double jacketed vessel. This premix was kept under stirring in high speed disperser for about 10-20 min to have uniform mixture. This was followed by addition of pigment green 7 (10-11%), the prepared Laponite RD jelly (8-13%) was added to above mixture and continued the stirring, and then extender calcium carbonate (27-28%) was added and continued the stirring for another 5-10 min. Weight equivalent to the above mill base, zirconia beads were added as grinding media. The grinding was performed for about 45-60 min at 3000 rpm. Propylene glycol (2-3%), triethylene glycol (6-7%), TegofoamexK3 (0.2-0.25%), PaxgardAP001 (0.2%), AcrysolDR130 (1-1.3%), and water (to adjust to 100%) were added to complete the batch and mixed well for about 10 min at 700 rpm. Then it was filtered and stored in a container till further evaluation. The sample was used to check for the viscosity, pH, and coloristics. All the minimal critical tests found acceptable, accelerated stability was also found acceptable.

Example-2: Scale up to 20 times higher batch using 13% Laponite RD gelly
Liquids such as water (6-8%), Propylene Glycol (3-5%), Triethylene glycol (4-6%), AtsurfD901 (2-3%), Dipentine (0.5-1%), TroysonS107 (0.15%), LA198 (0.15-0.25%) and Loramine101 (0.1-0.15%) were weighed and poured into the container of stator-rotor (R-S). This premix was kept under stirring for about 10-20 min to have uniform mixture. This was followed by addition of Pigment Green 7 (10-11%), the prepared Laponite RD jelly (13%) was added to above mixture and continued the stirring, and then extender calcium carbonate (27-28%) was added and continued the stirring for another 5 min. The above mill base was subjected for grinding in R-S for about 60-90 min at the tip speed of 12-18 m/s. Mill base viscosity was adjusted for passing it through the Dyno mill for further grinding. Dyno mill shell was filled with of Ziorconia beads (~ 80% of shell volume) before passing the mill base. Appropriate flow rate was adjusted. Two pass were given and the results of both the pass were compared to the reference sample and comparable results were obtainedto said reference sample.
Propylene glycol (1-2%), Triethylene glycol (5-6%), TegofoamexK3 (0.2-0.25%), PaxgardAP001 (0.2%), 1:1 mixture of water and AcrysolDR130 (2-2.6%), Loramine101 (0.1-0.15%), and Water (to adjust 100%) were added to complete the batch and mixed well for about 10-20 min at 500-700 rpm
Initial coloristics, accelerated stability tests were found satisfactory. The scrub resistance test was superior by at least 20 cycles compared to the dispersion when no Laponite RD was used.The data are shown in Table 1.

Example-3: Scale up to 20 times higher batch using 11% Laponite RD gelly

Liquids such as water (6-7%), Propylene Glycol (3-5%), Triethylene glycol (6-8%), AtsurfD901 (2-3%), Dipentine (1%), TroysonS107 (0.15%), LA198 (0.15-0.2%) and Loramine101 (0.1-0.15%) were weighed and poured into the container of stator-rotor (R-S). This premix was kept under stirring for about 10-20 min to have uniform mixture. This was followed by addition of Pigment Green 7 (10-11%), the prepared Laponite RD jelly (11%) was added to above mixture and continued the stirring, and then extender calcium carbonate (27-28%) was added and continued the stirring for another 5 min.The above mill base was subjected for grinding in R-S for about 60-90 min at the tip speed of 12-18 m/s. Mill base viscosity was adjusted for passing it through the Dyno mill for further grinding. Dyno mill shell was filled with of Ziorconia beads (~ 80% of shell volume) before passing the mill base. Appropriate flow rate was adjusted. Two pass were given and the results of both the pass were comparable to reference sample which required 2 pass.

Propylene glycol (1-2%), Triethylene glycol (4-5%), TegofoamexK3 (0.2-0.25%), PaxgardAP001 (0.2%), 1:1 mixture of water and AcrysolDR130 (1.5-1.8%), Loramine101 (0.1-0.15%), and Water (to adjust to 100%) were added to complete the batch and mixed well for about 10-20min at 500-700 rpm.
Coloristics, viscosity, pH, accelerated stability results are acceptable. The scrub resistance test was superior by at least 30 cycles.The data are shown in Table 1.
In above all batches, the zeta potential was ~ -20 mV which is similar to the zeta potential of pigment dispersion prepared with existing procedure. Few critical shades were prepared and found acceptable.
Table 1: Properties for colorants at lab scale
Properties 11 % Laponite RD Gelly 13 % Laponite RD Gelly Reference: No Laponite RD used
1 Dyno Pass 2 Dyno Pass 1 Dyno Pass 2 Dyno Pass 2 Dyno Pass
Tinting Strength (%) 100.6 101.2 96.2 97.4 -
Viscosity (KU) 62 64 63 65 68
pH 9.34 9.40 9.57 9.70 8.77
Zeta potential (mv) -19.2 -18.0 - -20.6 -19.8
Increase in Scrub Resistance (Cycles) ~330 ~330 ~320 ~320 ~300

It is important to mention that % of the glycols, terpene oil, surfactant was found to be critical below and beyond which the performance properties were found to be affected.

It is thus possible by way of the present advancement to provide for pigment dispersion and process thereof that offers organic pigment dispersion particularly phthalocynanine pigments, more particularly phthalocyanine pigment green 7 dispersion in high level of (10-11%) by involving clay Laponite RD. The coloristics are at par or superior with the dispersions prepared using existing method which uses conventional dispersing agents. The colorant processing is similar to the existing process. Very low pigmentation and high amount of clay are used in prior art, whereas present invention enables dispersion of high levels of pigment (10-11%) with low levels of Laponite RD (0.5% to 0.65%) together with low levels of surfactant.
Additionally it is worth mentioning that similar procedure could be adopted for successful dispersion of the pigments such as Pthalocyanine blue PB 15.1, 15.3 etc., quinacridone pigment PR 122 etc.involving Laponite RD jelly.