Claims:We Claim:

1. A polymer with reduced film forming temperature comprising copolymer of acrylates obtained of emulsion polymerization involving mono ethylenically-unsaturated di-acid monomer added after 2 hours of initiation of polymerizationwithacid functional groups grafted more onto the outer periphery of said copolymer thereby providing for a polymer with improved hydrophillicity facilitating reduction of minimum film forming temperature (MFTT) of said polymer and/or coating formulations thereof.

2. A polymer with reduced film forming temperature as claimed in claim 1 comprising said ethylenically-unsaturated di-acid monomer in the copolymer backbone adapted for reducing minimum film forming temperature (MFTT) of said polymer and/or coating formulations thereof, also adapted to reduce the amount of coalescent materialsin coating formulations.

3. A polymer with reduced film forming temperature as claimed in anyone of claims 1 or 2 as stable dispersion free of any protective colloids to stabilize said dispersion.

4. A polymer with reduced film forming temperature comprising copolymer of acrylates as claimed in anyone of claims 1-3 wherein said mono ethylenically-unsaturated di-acid monomer is Itaconic acid free of any neutralized itaconic acid and/or itaconic acid salt.

5. A polymer with reduced film forming temperature as claimed in anyone of claims 1-4 comprising copolymer of acrylates obtained of 0.25-0.75 wt.% Itaconic acid added after 2 hours of the initiation of polymerization.

6. A polymer with reduced film forming temperature as claimed in anyone of claims 1-5 wherein said copolymer of acrylates obtained of addition of 0.25-0.75 wt.% Itaconic acid after 2 hours of initiation of polymerization favours increase of hydrophillicity to thereby reduce the film forming temperature by 2-4 ?C as compared to a polymer free of itaconic acid, said copolymer having glass transition temperature in the range between 21°C to 35°C.

7. A polymer with reduced film forming temperature as claimed in anyone of claims 1-6 favouringreducing the amount of coalescent materialsin coating formulationspreferably texanolby at least 10% on polymer solids thereby reducing the volatile organic content of coating formulations/ paints.

8. A process for manufacture of polymer with reduced film forming temperature as claimed in anyone of claims 1 to 7 comprising emulsion polymerization of acrylate monomers involving mono ethylenically-unsaturated di acid monomerpreferably itaconic acid wherein delayed addition of the same in the reaction mixture provides for polymer having acid groups more onto the outer periphery of the polymerwith improved hydrophillicity facilitating reduced film forming temperature of said polymer and/ or coating formulations thereof thereby facilitatingreduction in the amount of coalescent materials in coating formulations.

9. A process for manufacture of polymeras claimed in claim 8 wherein addition of Itaconic acid is delayed for 2 hours from the initiation of single stage free radical emulsion polymerization favouring grafting of the same onto the outer periphery of the polymer thus attained resulting in improvedhydrophillicity of said polymer.

10. A process for manufacture of polymeras claimed in claims 8 or 9 wherein addition of 0.25-0.75 wt.% Itaconic acid after 2 hour of initiation of polymerization causes improved hydrophilicity of the resulting polymer thereby favoring reduction of film forming temperature by 2-4?C of said polymer and/or coating formulations thereof compared to a polymer free of itaconic acid, said copolymer having glass transition temperature in the range between 21°C to 35°C.

11. A process for manufacture of polymeras claimed in claim 8-10 comprising the steps of
(i) providing a reactor charge comprising sequential addition of demineralized water, anionic surfactant, non-ionic surfactant;
(ii) providing monomer Pre-emulsion comprising sequential addition of Pre-emulsion ingredients;
(iii) heating the reactor charge to about 80°C followed by addition of 5% pre-emulsion into the reactor further followed by addition of Sodium bicarbonate, potassium persulphate solution and held for about 10 minutes;
(iv) adding the remaining pre-emulsion for about a period of 4 hrs to the reactor charge wherein after completion of 45 minutes of addition of pre-emulsion, Vinyl trimethoxy silane (VTMO) was added into the pre-emulsion mixed and the addition continued throughout 4 hours by maintaining a temperature of 80°C;
(v) post completion of pre-emulsion addition, the temperature of the reactor was brought down to 75°C and maintaining the temperature for about 1 hour for digestion by addition of digestion catalyst, said digestion catalyst was separately prepared over a period of 5 to 10 minutes as a separate feed, simultaneously;
(vi) cooling the reactor to about 30°C for the addition of additives mixed for about 5 minutes followed by filtration yielding said polymer and/ or coating formulations thereof.

12. A process for manufacture of polymer as claimed in claims8-11 wherein said prepolymer emulsion comprises demineralized water, Anionic surfactant preferably Alkyldiphenyloxide Disulfonate (as 45%sol), Non-ionic surfactant preferably a mixture of ethoxylated linear fatty alcohols (as 65% sol), diacetone acrylamide, MMA monomer, 2-ethyl hexylacrylate monomer, HEMA, glacial methacrylic acid, potassium persulfate.

13. A process for manufacture of polymer as claimed in claims 8-12 wherein the reactor charge comprises demineralized water, Anionic surfactant preferably AlkyldiphenyloxideDisulfonate (as 45%sol) Non-ionic surfactant preferably mixture of ethoxylated linear fatty alcohols as 65% sol and potassium persulfateto which said pre-emulsion is added.

14. A process for manufacture of polymer as claimed in claims 8-13 wherein said digestion catalyst comprises demineralized water, sodium formaldehyde sulphoxlate, tertiary butyl hyderoperoxide, Non-ionic surfactant preferably a mixture of ethoxylated linear fatty alcohols 65% sol.

Dated this the 9th day of August, 2018 Anjan Sen
Of Anjan Sen and Associates
(Applicants Agent)
IN/PA-199
, Description:FIELD OF THE INVENTION
This invention relates to acrylic polymer with reduced minimum film forming temperature (MFFT) and process of reducing the samefor acrylic polymers that would in turn facilitate reducing the amount of texanol in coating formulations thereby reducing the volatile organic compound in the system.

BACKGROUND ART
Volatile organic compounds (VOC) is a serious concern for the ozone layer of the atmosphere and the environment surrounding us. As a result the environment protection agencies all over the world have framed stringent rules and regulations relating the use of VOCs in different aspects of its application. Various paint and ink formulation comprising of complex mixture of different components including formaldehyde based binders is one of the major source for VOCs. Also among them lowering the use of coalescent in coating formulations thereby reducing the volatile organic compounds is quite noteworthy to reduce the minimum film forming temperature of the polymer in said formulation.
In this regard itaconic acid has been used as a component to reduce the minimum film forming temperature of the desired polymer and on this references are drawn to several prior arts as discussed hereunder:
US5336744 relates to novel process for the preparation of polymers of itaconic acid carried out with partially neutralized itaconic acid, an initiator, and a polyvalent metal ion wherein the polyvalent metal ion source is ferric ammonium sulfate with high conversion.Polymers made by this process are suitable for use as detergent additives, scale inhibitors and removers, sequestrants, yarn sizers, deflocculating agents, de-inking agents, suspending agents and dispersing agentsand does not relate to any reduction of minimum film formation temperature based on the use of the same.
CA2322590 discloses aqueous pigment preparations containing i) at least one copolymer P of ethylenically unsaturated monomers M in the form of an aqueous polymer dispersion which contains polymerizedmonomer of itaconic acid M1, its salts and/or anhydrideand whose glass transition temperature Tg lies between -10 and +50 ~?C; ii) at least one inorganic pigment; iii) possibly inorganic fillers; and iv) standard additives. Said Pigmented formulations are employed widely in the form of coating compositions, especially emulsion paints, synthetic-resin-bound plasters (dispersion plasters), sealing compounds or filling compositions for purposes of architectural protection or decoration and relates to the use of the copolymers P containing itaconic acid for improving the wet-abrasion resistance of polymer-bound coatings containing pigments.
US5223592 relates to polymers of itaconic acid that are formed at high conversion by adding completely neutralized monomer solution (salt of itaconic acid) and initiator solution to a vessel initially containing water at a temperature sufficient for polymerization and overcomes the hurdle of preparation of polymers of itaconic acid partially resolvinginherent difficulties in polymerizing this dicarboxylic acid where low polymerization conversion of the acid continues to be a problem. Thesebiodegradable polymers of itaconic acidare suitable for use as detergent additives, scale inhibitors and removers, sequestrants, yarn sizers, deflocculating agents, de-inking agents, suspending agents and dispersing agents.
US20140296463 relates to polymers comprising structural units derived from itaconic acid which are useful, including uses as binders for fiberglassand offers a green solution over the use of formaldehyde-based binders which comprise a high degree of volatile organic compound (VOC) problem.
EP2767563 discloses elastomeric roof coating compositions of elastomeric carboxyl group containing acrylic emulsion copolymers having good resistance to water swelling and dirt pick up resistance which comprises an emulsion copolymers having a glass transition temperature (Tg) of from -45°C to -10°C that is the copolymerization product of a monomer mixture alkyl(meth)acrylates, vinyl monomer anditaconic acid (IA), and one or more additional acid monomer chosen from an ethylenically unsaturated acid functional monomer.
US5006408 deals with non-halogenated hydrocarbon polymeric compositions and process which impart durable stain resistance to fibrous substrates, particularly nylon containing articles wherein the composition are particularly adventitious in that they are comprised mainly of low toxicity monomers derived from a renewable resource, e.g.itaconic acid butsuffers from the limitations of using organic volatile solvents during the synthesis.
EP2886614 discloses a composition comprising a) a stable aqueous dispersion of polymer particles functionalized with structural units of itaconic acid or a salt thereof and; b) a watersoluble polymer functionalized with structural units of a sulfonic acid monomer or a salt thereof as well as a method comprising mixing the stable aqueous dispersion of the itaconic acid functionalized polymer particles with the sulfonic acid functionalized polymer, and TiO2 that surprisingly provides good hiding.
US20150051334 discloses polymer latex binders useful for preparing coating compositions containing low levels of, or which are substantially free of, volatile organic compounds (VOCs) such as volatile freeze-thaw additives and are prepared by multistage emulsion polymerization, wherein one stage provides a copolymer having a relatively high glass transition temperature and containing an oxyalkylene-containing (meth)acrylate co-monomer.
EP1234840 describesa method for improving the scrub resistance of a coating, a method for lowering the minimum film formation temperature of an aqueous coating composition and a method for improving the adhesion of a coating to a substrate wherein an emulsion was made by theemulsion polymerization of Bu acrylate, Me methacrylate, methacrylic acid and also co-monomer of monoethylenically-unsaturated acid monomer such as, for example, itaconicacid, acrylic acid, methacrylic acid, crotonic acid, fumaric acid, etc in H2O in the presence of tertBu hydroperoxide polymerization initiator. However, the effect of itaconic acid on minimum film forming temperature is not disclosed in the art.
CN105175614 teaches the formation of core-shell polymer particle which uses itaconic acid as one co-monomer. The core, the transition layer, the support layer, and the film forming layer of the title particle are independently deposited by emulsion polymerization. The emulsion could be stored at room temperature for over 180 days; it contained multilayer core-shell particle with outside diameter 0.59 µm and inside diameter 0.41 µm.Itaconic acid used here is to make hollow polymer particle and does not indicate any lowering of minimum film forming temperature based on the use of the same. However, it relates to get lowest film forming temperature through core shell method which is a well-known concept in emulsion polymer chemistry.
CN102757536A discloses hollow polymers prepared by multistage polymerization can be used as a substitute for TiO2 and organic pigments used in paints, paper/ cosmetics/ fine chemicals and other fields. In addition discloses a method for reducing the coalescing demand in paint aimed to reduce pigments in paint.
US20120252972 is directed to good shelf life and film forming ability at low temperature for coatingwith good hardness, wet adhesion, and blocking resistance achieved by multistage radical emulsion polymerizationof acrylic monomers with itaconic acid as a constitute.
EP2014706 teaches aqueous polymeric dispersion comprising (a) =1 polymer in aq. Dispersionhaving a minimum film-forming temperature (MFFT) 0-100°, (b) 0.05-30%, preferably 0.1-30% =1 carboxylic acid (coalescing and/or plasticizing agents) having 1-25 C atoms, or oftheir mixtures. The end-use composition comprising the aqueous polymeric dispersion is forpeelable coatings, industrial protective coatings and food protective coatings are preferred.This prior patent highlights and claims that the polymer composition forms polymer film between 0 to 100 0C with use of monomers and functional monomers and does not indicate any effect of concentration of itaconic acid (IA) upon minimum film forming temperature and the stage of its addition during polymerization.
JP2002226524A describes a latex containing an acrylonitrileacrylic acid, butadiene, itaconic acid, Me methacrylate,-styrene and methylstyrene dimer graft copolymer with Tg1 31° andTg240° with MFT 28° was mixed with additives to form paper coating showing high dry and wet pickup strength and good blister resistance (210°), tackiness prevention, and re-dispersibility. The copolymer is made using two stages with different Tg (Glass Transition Temperature) and does not mention any process of synthesizing acrylic polymer using itaconic acid for reducing minimum film forming temperature or glass transition temperature.

JP2003138233 teaches compositions with good coatability, contain 100 parts (solid content) rubberlatexes containing emulsion-polymerized 0.3-10:90-99.7 OH-containing vinyl compound othervinyl compounds copolymers having film-forming temp. (T1) of 0-20° and PhMe-gel content(G1) of 40-90%, 0.1-10 parts wax emulsions, and 0.1-10 parts polyurethanes. The composition was coated on a paper to 40 g/m2 thickness to form a film with good adhesion to the paper and moisture permeability 55 g/m2- 24h. This prior patent does not teach a process of synthesizing acrylic polymer using itaconic acid for reducing minimum film forming temperature or glass transition temperature.
EP1262521 is directed to aqueous dispersions of polymers prepared by redox emulsion polymerization of acrylamide 19.5, itaconic acid 41.5, Bu acrylate 383.5, and styrene 254.8 g gave a 49.6% emulsion with particle size 143 nm and minimum film-forming temperature of 1°. This emulsion was used in a pigmented composition giving coatings with wet scouring resistance >10,000 cycles and does not teach any on thermal (radical) polymerization process and further wherein the minimum film forming temperature of this prior art patent is not due to IA but due to compositional effect.
JP2002302876 teaches resins having glass transition temperature -40° to 10° were prepared from hydrophobicmonomers such as alkyl (meth)acrylates and arylvinyl compounds having solubility <1 g/100 g water 20-91, C3-5 a, s-unsaturated mono- or dicarboxylic acids 2-10, hydrophilic unsaturated monomers having amide, OH groups, or derivatives thereof 2-12, and co-monomers having solubility >1 g/100 g water 075%. The dispersions are alkali-thickenable and have low film forming temperatures. Thus, 6.0:5.0:35:44:10 acrylamide-acrylic acid-Et acrylate-2- ethylhexyl acrylate-styrene copolymer was prepd. using DKS NL 250 and Monogen Y 500 as emulsifiers.Para [0025] while teaches the unsaturated carboxylic acid (b), for example, acrylic acid, methacrylic acid, itaconic acid, fumaric acid, maleic acid, maleic anhydride, crotonicacid,citraconic acid, cinnamic acid, etc. of these, the polymerization stability of the good,copolymerizable good with other monomers, as well as the reason for such is excellent inmechanical stability and storage stability of the resulting acrylic copolymer aqueous dispersion from, acrylic acid, methacrylic acid, the use of itaconic acid is particularly preferred, does not relate the presence of IA to reduce MFFT of a polymer film.
JP2002226524 discloses prior art latexes contain copolymers prepared from conjugated dienes 20-80,unsaturated acids 0.5-10, cyano vinyl compounds 3-50, and other monomers 0-76.5% andhaving =2 glass-transition temperature at Tg 1 - Tg 2 of =5° and (Tg 1- MFT)/(Tg 1- Tg 2) of =0.5 (Tg 1, Tg 2 = max. and min. glass-transition temperature of the copolymer; MFT =minimum film-forming temperature of the copolymer). A latex containing an acrylonitrile acrylic acid-butadiene-itaconicacid- Methyl methacrylate-styrene-a-methylstyrene dimer graft copolymer with Tg 1 31°, Tg 2 -40°, and MFT 28° was mixed with additives to form paper coating showing high dry and wet pickup strength and good blister resistance (210°), tackiness prevention, and re-dispersibility. This prior patent claims about the copolymer which is made using two stages with different Tg (Glass Transition Temperature) displays high dry and wet pickup resistance and blister resistance and does not relate to any reduction of MFFT by use of IA addition at a certain stage of polymerization.
JP03076896 teaches prior art coatings obtained from 100 parts pigments and 10-30 parts binders whichare latexes containing multilayer particles with average diameter 0.1-0.25 µm, and have minimal film-forming temperature (Tf) =20°. The latexes are prepared by a 2-steps emulsionpolymerization of (A) mono-olefins, unsaturated carboxylic acids and optionally conjugated olefins to a copolymer having glass temperature (Tg) =50°; and (B) unsaturated carboxylic acids and cyanovinyl monomers in the A:B ratio of 30-70:70-30. Thus, a latex of polymer particles with core component (Tg 102°) from styrene 26, Me methacrylate 16, acrylic acid 1, and seed 0.41; and shell from butadiene 30, styrene 16, acrylonitrile 7, acrylic acid 2, and itaconic acid 2 parts was prepared having Tf<0° and particles with size 0.24 µm. Coating paper with a 62%-solids aqueous dispersion containing 12 parts latex, 50 parts clay, 50 parts high-d. CaCO3 and additives gave coated sheet with paper-gloss 25%, inked gloss 36%, and stiffness 195 mm/mm (in width).This prior patent claims making a polymer using core-shell two stage polymerization process wherein core shell morphology of the thus synthesized polymer is partially responsible for low film forming temperature.
JP01299876 is directed to compositions containing emulsions of copolymers (particle size 0.02-0.2 µm; minimum film-forming temperature ?30°) of unsaturated carboxylic acids, C4-10 alkyl(meth)acrylates, and optionally styrene, emulsions of copolymers (particle size 0.05-0.5 µm)of 30-85% H2C:CCl2 and C4-10 alkyl (meth)acrylates, and emulsions of chlorinated rubbers.Mixing 100 parts emulsion containing 50% copolymer of methacrylic acid (I) 20, itaconic acid 5, 2-ethylhexyl acrylate 187, styrene 275, and acrylamide 3 parts with 100 parts emulsion containing 50% copolymer of H2C:CCl2 288, Bu acrylate 192, acrylic acid 2.5, and I 7.5parts, 500 parts emulsion of Superchlone 907 MA (chlorinated polyethylene), and 300 parts H2O gave a primer which was coated on a flexible board, dried 2 h, topped with a finish coating, and dried 14 days. The coating had adhesion (kg/cm2) 16 initially and 18 after 7 days in H2O and drying, vs. 12 and 10, resp., without Superchlone 907 MA. This prior patent claims about a copolymer composition which forms film at a temperature less than 30?C and particularly teaches a mixture of three emulsions leading to the formation of final resulting primer suspension and advantages generated from chlorinated rubber addition to the suspension.
JP55045724 discloses an aqueous dispersion of an emulsion-polymerized copolymer (2nd transition temp. >60°)was mixed with a monomer mixture (polymer: monomer = 3-7:7-3) which was thenpolymerized to give a latex (min. film-forming temp. <25°, av. particle size 0.11.0 µ) usefulas coating for paper for gravure printing. For example, water 70, sodium dodecylbenzenesulfonate 0.1, NaOH 0.2, K2S2O8 0.3, 96:4 styrene-acrylic acid copolymerlatex (particle size 0.03 µ) 0.26, styrene 20, Me methacrylate 21, and acrylic acid 2 partswere heated at 80% for 3 h (conversion 90%, 2nd transition temp. 95°), treated with styrene28, butadiene 28, itaconic acid 1, C12H25SH 1, NaOH 0.2, K2S2O8 0.3, and NaDodecylbenzenesulfonate 0.2 part, and heated at 80° for 4 h to give a latex with min. filmforming temp. 20° and particle size 2700 A. Clay 80, CaCO3 20, and dispersant 0.2 part were dispersed in water, mixed with 10 parts of the above latex and 5 parts starch, adjusted to 60% solids content, coated on paper, dried at 105° for 60s, and conditioned at 23° and relative humidity 65% for 24 h to give coated paper with excellent gravure printability. This prior patent does not relate to reduction in MFFT with the addition of IA.
JP54131013 is directed to low-gloss CaCO3 coating compositions for paper contained a latex (min. film-forming temp.??25°) of layered copolymer particles (0.1-1 µ) prepared by copolymerization of emulsion-polymerization prepolymer (2nd transition temp. < 60°) with co-monomer in 30-70: 70-30 ratio in aq.medium. For example, water 65, C12H25C6H4SO3Na 0.1, NaOH 0.2, K2S2O8 0.2, 16:4styrene acrylic acid copolymer (seed, 0.03 µ, in latex) 0.26, styrene 20, Me methacrylate 21, and acrylic acid 2 parts were heated at 80° for 3 h (90% conversion), treated with styrene 28, butadiene 28, itaconic acid 1, C12H25SH 1.0, NaOH 0.2, K2S2O8 0.2, and12H25C8H4SO3Na 0.2 part, heated at 80° for 4 h, and treated with NaOH to pH 8.0 to give a latex (I). Paper coated with a 60%-solids aqueous composition containing CaCO3 80, clay 20, dispersant 0.2, oxidized starch 8, and I 18 parts had gloss 23.0%, print gloss 80.4%, andwhiteness 85.9%, compared with 17.8, 57.7, and 83.0% resp., for a control using SBR latexin place of I. This prior patent claims an emulsion polymer made using an emulsion which is mixed with a monomers mixture and then polymerize to get a copolymer composition useful for paper coating application which form film at less than 25 C and does not relate to reduction in MFFT due to the addition of IA.
JP52102363 relates to a water-thinned, film-forming compositions curable at low temperature were prepared bysuspension polymerization of monomer(s) chosen from acrylonitrile, alkyl (meth)acrylate, and styrene 100, dibasic acid monomer 1-10, glycidyl methacrylate 1-60,N-methylol (meth)acrylamide 0.5-7, alkyl sulfate salt or alkyl or arylsulfonate 0.1-1, and colloidal silica 0.2-1.5 parts. For ex., a suspension polymerization mixture (polymd. at 60-40°, 3 h) from glycidyl methacrylate 10, Me methacrylate 200, Bu acrylate 182, itaconic acid 4, N-methylolacrylamide 4, 10% aq. Na laurylsulfonate 20, Ludox AM 8, water 452, 25% aq. (NH4)2S2O8 60, and 1.25% aq. Na2S2O5 60 parts was free from agglomeration and storable>6 mo at 40°, and formed films and coatings at room temp. with good resistance to water,blocking, and chemicals. This prior art patent does not teach emulsion polymerization process where the MFFT reduction of the polymer film is achieved at certain concentration and addition stage of itaconic acid.
US3714096 is directed to self-crosslinking aqueous vinyl acetate latexes, useful as coatings, that were manufactured byemulsion polymerizing vinyl acetate (I) 51-98, film-forming-temperature regulating acrylateester or unsaturated nitrile 5-25, N-methylolacrylamide crosslinking monomer 1-3, synergistic 2nd crosslinking agent 0.05-1.0, and unsaturated carboxylic-acid 0.1-1% in the presence ofanionic or nonionic emulsifying agents. Thus, in 2 hr, a solution of Bu acrylate (II) 213,diallyl maleate 15.8, and I 1205 g was added, under N at 160deg.F to a mixt. of H2O 2500,Aerosol A 102 (a di-Na sulfosuccinate ester of an ethylene glycol mono C10-12 alkyl ether)213, I 266, II 45, and K2S2O8 5 g. A soln. of 213 g II in 1205 g I was added during the next 2 hrs, while a solution of N-methylolacrylamide 105, itaconic acid 15.8, and Aerosol A 102 wasadded in the 1st 4 hr of polymerization. After 1 additional hr at 150.deg.F, a soln. of 1.5 g K2S2O8 in25 g H2O was added and polymerization was continued until the residual monomer contentwas 0.5%. Coatings prepared from the resultant latex containing 50.5% butyl acrylate-diallylmaleate, itaconic acid, N-methylolacrylamide-vinyl acetate polymer were highly crosslinked after curing for 3 min at 270 deg. and were solvent resistant with 79% remaining undissolved at 16-18 hr in C6H6 at 750 F.This prior patent does not claim the reduction of MFFT of the polymer film.
BE665466 relates to aqueous dispersions containing particles (=95% 0.01-0.1 µm) of copolymers of Memethacrylate (I) with 3-6 wt. % acrylic acid, 3-6 wt. % methacrylic acid (II), 4-6 wt. %maleic acid, or 4-6 wt. % itaconic acid (in which 40-85 mol % of the acid is in the form of an ammonium or amine salt) are prepared and are film-forming at room temperature. Thus, a mixture of 17,150 g. H2O and 50 g. starch was heated for 15 min. at 90°, cooled to roomtemp., treated with (in the following order): Et acrylate 4200, 9500, BuSH 40, and II 700 gand heated to 90°. The mixture is treated with a soln. of 47.3 g. azodiisobutyronitrile in 1000 mL MeOH at 12 mL/min., treated with 115 mL catalyst soln. at 82°C, heated to 96°C after 2-3 min., and cooled to give 158.5 g. polymer. A mixture of polymer, 245 g. H2O, 45.3 g. EtO(CH2CH2O)2H, and 4.4 g. 28% NH3 is heated to 70°, agitated for 5.5 h., cooled, andfiltered to give a dispersion, viscosity (25°) 315 cp., of particles of diam. 0.02-0.08 µm. This prior patent does not indicate any reduction of film forming ability of the polymer film by the addition of IA (itaconic acid).
WO2012130712A1 is directed to aqueous dispersions with good shelf life and film-forming ability atlow temperatures for manufacture of coatings with good hardness, wet adhesion, andblocking resistance are manufactured by radical emulsion polymerization of (A) =1(meth)acrylate ester, (B) optionally, =1 C=20 vinyl aromatic compound, (C) optionally, C=20 ethylenically unsaturated nitriles, C=20 vinyl esters of carboxylic acids, C=10 vinyl ethers of alcs., (D) =1 ethylenically unsaturated carboxylic acid or vinyl compd. with latent ionic groups, (E) optionally =1 crosslinker, (F) =1 compd. selected from 2-(2-oxoimidazolidin-1-yl)ethyl(meth)acrylate, 2 ureido(meth)acrylate, acetoacetoxyethyl acrylate, Acetoacetoxypropyl methacrylate, acetoacetoxybutyl methacrylate, acetoacetoxyethyl methacrylate, and diacetone(meth)acrylamide, (G) optionally, =1 compd. Having a (meth)acrylate group and an epoxy group, and (H) optionally, =1 ethylenically unsaturated carboxamide, base neutralization to pH =4.5, and radical polymerizationof the same compounds (A)- H) in the same product mixture, with the provision that the polymer of the 2nd stage is more hydrophobic than that of the 1st stage and the glass transition temp. of the polymer from the 2nd stage is =50° lower than that of the 1st stage. A typical dispersion was manufactured by radical polymerization of methacrylic acid 8.1, acrylic acid 1.9, styrene 12.5, Me methacrylate (I) 80.0, Bu Acrylate (II) 12.5, and diacetoneacrylamide 10.0, neutralization of the dispersionwith NH3 soln. and radical polymn. of 260 g II and 115 g I in the same dispersion. Further one of the claims of this prior art states that the polymer dispersion characterized in that the monomers (D1) and / or (D2) are selected from the group consisting of (meth) acrylic acid, crotonic acid, itaconic acid, maleic acid or fumaric acid. acrylic polymer dispersion which are film forming at low temperature synthesized by “double stage polymerization”.The copolymer obtained from the first stage has a glass transition temperature of 50 to 150°C and the product obtained from the second stage is lower by at least 50°C glass transition temperature. This prior patent does not explicitly describe the process of reducing minimum film forming temperature of the aqueous polymer dispersion
JP2009197051A describes the use of itaconic acid for a composite polymer latex using two stage polymerization process.The monomer emulsion (F1) containing itaconic acid added dropwise in the first 2 hours, a carboxyl group-containing vinyl polymer (A1) is obtained as aqueous dispersion. This aqueous is neutralized with ammonia. Another monomer mixture (G1) is added dropwise (the synthesis of vinyl polymer (B1)) to this neutralized carboxyl group-containing vinyl polymer (A1') for 2 hours. Neutralized carboxyl group-containing vinyl polymer (A1) and the vinyl polymer (B1) from a complex composed polymer particles (C1) is thus obtained as an aqueous dispersion. The fast-drying properties of this aqueous dispersion is due to polymer weight ratio of A1 and B1.This prior art describes the use of itaconic acid for a composite polymer latex using two stage polymerization process.The monomer emulsion (F1) containing itaconic acid added dropwise in the first 2 hours, a carboxyl group-containing vinyl polymer (A1) is obtained as aqueous dispersion. This aqueous is neutralized with ammonia. Another monomer mixture (G1) is added dropwise (the synthesis of vinyl polymer (B1)) to this neutralized carboxyl group-containing vinyl polymer (A1 ') for 2 hours. Neutralized carboxyl group-containing vinyl polymer (A1) and the vinyl polymer (B1) from a complex composed polymer particles (C1) is thus obtained as an aqueous dispersion. The fast-drying properties of this aqueous dispersion is due to polymer weight ratio of A1 and B1. The prior art indicated here nowhere discloses the information of making polymer particle to reduce the minimum film forming temperature.
WO2008141721A1 discloses an aqueous dispersion of polymers containing an organic acid with coalescing and /or plasticizing agents for reducing MFFT of the dispersion.The said dispersion is stabilized with protective colloids and / or with surfactant and is prepared by emulsion polymerization or by dispersing in water a preformed polymer. The organic carboxylic acid is added to the preheated aqueous polymeric dispersion to obtain a homogeneous aqueous dispersion followed by adjusting the pH.This prior art therefore teaches employment of coalescing and /or plasticizing agents for reducing MFFT of the dispersion.
US3287300 discloses that simple mixing of monocarboxylic acid with vinyl ester polymer emulsion lowers the coalescence temperature wherein specifically, this prior art provides a process for preparing stable polyvinyl ester emulsions which comprises adding from 0.1% to 20% of an aliphatic monocarboxylic acid having at least 9 carbon atoms in the molecule based on the weight of polymer to an aqueous emulsion of a polyvinyl ester. It is known that after addition of a few percent of formic acid, acetic acid, propionic acid or butyric acid, an aqueous polymer emulsion may be successfully dried at a temperature lower than the above-mentioned minimum film-forming temperature. However, said acids are less suitable as additives for polymer emulsions because of their unpleasant odor. It is further known that the acids following the above mentioned aliphatic monocarboxylic acids in the homologous series, viz, valeric acid and caproic acid, are completely unserviceable for such purpose. Addition of as little as 2% of these latter acids to polyvinyl ester emulsions caused coagulation.Further research has now revealed that aliphatic mono carboxylic acids with nine or more carbon atoms in the molecule depress the minimum film-forming temperature without causing any coagulation of the polymer emulsions. Further, the very unpleasant odor of the lower carboxylic acids (particularly of butyric, valeric and caproic acids) is completely absent from these higher carboxylic acids.
EP1408057A1 relates to dispersions having a minimum film-forming temperature <10° C and a Tg of -20 °C to +20°C, obtainable by semicontinuous free-radical emulsion polymerization. The said dispersion contains at least 1 weight % of ethylenically unsaturated dicarboxylic acid and 2 weight % of ethylenically unsaturatedsilane monomers. In one of the experiments the minimum film forming temperature was found to be 3° C.
CN106221546A relates to multi-component self-crosslinking single-component waterborne polyurethane dispersion liquid used as coating. This liquid dispersion is a mixture of aqueous polyurethane dispersion and olefin high-polymer emulsion or dispersion. The aqueous polyurethane dispersion contains 2% of solvent. The minimum film forming temperature of this multi-component self-crosslinking single-component waterborne polyurethane dispersion liquid is from 0 to 45°C.
CN105949692A discloses a modified polyvinyl alcohol and its preparation process which uses vinyl acetate monomer, maleic anhydride and itaconic acid as one co-monomer and a plasticizer. Reduction of film forming temperature by using plasticizer is a well-known concept in industry. The above prior art nowhere mentions that use of itaconic acid with process modification in their recipe led to reduction in minimum film forming temperature.
Progress in Organic Coatings (2011), 72(3), 380-386 explored the influence of process variation viz; addition of Itaconic acid through pre-emulsion process, against a separate feed of itaconic acid (IA) along with other ingredients on polymer properties and paint performance. This publication also touched upon the effect of neutralization of itaconic acid at various levels viz; 10%, 25% and 50% using sodium bicarbonate before polymerization. in contrast to the present invention where itaconic acid was introduced in the reaction mixture as such in the form of acid and not salt.

While the above prevailing state of the artsappear to reveal common use of itaconic acid as the functional monomer in either double stage or single stage emulsion polymerization with acrylic monomers to produce polymer with lower minimum film forming temperature, without realizing the actual role played by itaconic acid. Additionally none of the above is directed to itaconic acid grafting onto the backbone and/ or surface of the acrylic polymer. It is thusan object of the present invention to explore the contribution of IA for MFFT and provide polymer with lower MFFT which would lead to low VOC coating composition.

OBJECTS OF THE INVENTION

The primary object of the present invention is to provide a simple process of reducing the minimum film forming temperature by 2-4?C of acrylic copolymer obtained from a mixture of co-monomers including acrylic monomers and itaconic acid by employing single stage thermal free radical emulsion polymerization.

Another object of the said present invention is to provide for said simple process for manufacturing acrylic polymer dispersion that would be having minimum film forming temperature reduced by 2-4?C due to the inclusion of itaconic acid in select amounts as co-monomer as compared to the acrylic polymer free of itaconic acid.

Yet another object of the present invention is to provide for said simple single stage thermal (radical) emulsion polymerization process of manufacturing acrylic copolymer with reduced MFTT that would in turn reduce the amount of coalescent (texanol) by at least 10% on polymer solids, thereby reducing the volatile organic content of coating/ paint systems.

Still another object of the present invention is to provide for said simple emulsion polymerization process of manufacturing acrylic copolymer with reduced MFTT including itaconic acid added as a co-monomer in the polymer backbone in select amounts and in select stage of emulsion polymerization that would act as a coalescence aid to the polymer particle.

Yet another object of the present invention is to provide for said simple emulsion polymerization process whereby addition of solid (itaconic acid) instead of evaporating liquid would enable reduction of MFFT of acrylic copolymer based coatings thereby reducing coalescent requirement.

SUMMARY OF THE INVENTION
Thus according to the basic aspect of the present invention there is provided a polymer with reduced film forming temperature comprising copolymer of acrylates obtained of emulsion polymerization involving mono ethylenically-unsaturated di-acid monomer added after 2 hour of initiation of polymerization with acid functional groups grafted more onto the outer periphery of said copolymer thereby providing for a polymer with improved hydrophillicity facilitating reduction of minimum film forming temperature (MFTT) of said polymer and/or coating formulations thereof.

Another preferred embodiment of the present invention is to provide a polymer with reduced film forming temperaturecomprising said ethylenically-unsaturated di-acid monomer in the copolymer backbone adapted for reducing minimum film forming temperature (MFTT) of said polymer and/or coating formulations thereof, also adapted to reduce the amount of coalescent materials in coating formulations.
Yet another preferred embodiment of the present invention is to provide a polymer with reduced film forming temperature as stable dispersion free of any protective colloids to stabilize said dispersion.
Preferably the present invention provides a polymer with reduced film forming temperature comprising copolymer of acrylates wherein said mono ethylenically-unsaturated di-acid monomer is Itaconic acid free of any neutralized itaconic acid and/or itaconic acid salt.
Another embodiment of the present invention is to provide a polymer with reduced film forming temperaturecomprising copolymer of acrylates obtained of 0.25-0.75 wt.% Itaconic acid added after 2 hours of the initiation of polymerization.
Another embodiment of the present invention is to provide a polymer with reduced film forming temperaturewherein said copolymer of acrylates obtained of addition of 0.25-0.75 wt. % Itaconic acid after 2 hours of initiation of polymerization favours increase of hydrophillicity to thereby reduce the film forming temperature by 2-4 ?C as compared to a polymer free of itaconic acid, said copolymer having glass transition temperature in the range between 21°C to 35°C.
Yet another embodiment of the present invention is to provide a polymer with reduced film forming temperaturefavouring reducing the amount of coalescent materials in coating formulations preferably texanol by at least 10% on polymer solids thereby reducing the volatile organic content of coating formulations/ paints.

Another prime embodiment of the present invention is to provide a process for manufacture of polymer with reduced film forming temperature comprisingemulsion polymerization of acrylate monomers involving mono ethylenically-unsaturated di acid monomer preferably itaconic acid wherein delayed addition of the same in the reaction mixture provides for polymer having acid groups more onto the outer periphery of the polymer with improved hydrophillicity facilitating reduced film forming temperature of said polymer and/ or coating formulations thereof thereby facilitatingreduction in the amount of coalescent materials in coating formulations.

Another embodiment of the present invention is to provide a process for manufacture of said polymerwherein addition of Itaconic acid is delayed for 2 hours from the initiation of single stage free radical emulsion polymerization favouring grafting of the sameonto the outer periphery of the polymer thus attained resulting in improved hydrophillicity of said polymer.

Another embodiment of the present invention is to providea process for manufacture of polymeras wherein addition of 0.25-0.75 wt. % Itaconic acid after 2 hours of initiation of polymerization causes improved hydrophilicity of the resulting polymer thereby favoring reduction of film forming temperature by 2-4?C of said polymer and/or coating formulations thereof compared to a polymer free of itaconic acid, said copolymer having glass transition temperature in the range between 21°C to 35°C.

Another embodiment of the present invention is to provide a process comprising the steps of
(i) providing a reactor charge comprising sequential addition of demineralized water, anionic surfactant, non-ionic surfactant;
(ii) providing monomer Pre-emulsion comprising sequential addition of Pre-emulsion ingredients;
(iii) heating the reactor charge to about 80°C followed by addition of 5% pre-emulsion into the reactor further followed by addition of Sodium bicarbonate, potassium persulphate solution and held for about 10 minutes;
(iv) adding the remaining pre-emulsion for about a period of 4 hrs to the reactor charge wherein after completion of 45 minutes of addition of pre-emulsion, Vinyl trimethoxysilane (VTMO) was added into the pre-emulsion mixed and the addition continued throughout 4 hours by maintaining a temperature of 80°C;
(v) post completion of pre-emulsion addition, the temperature of the reactor was brought down to 75°C and maintaining the temperature for about 1 hour for digestion by addition of digestion catalyst, said digestion catalyst was separately prepared over a period of 5 to 10 minutes as a separate feed, simultaneously;
(vi) cooling the reactor to about 30°C for the addition of additives mixed for about 5 minutes followed by filtration yielding said polymer and/ or coating formulations thereof.

Another embodiment of the present invention is to provide a process for manufacture of polymer wherein said prepolymer emulsion comprises demineralized water, Anionic surfactant preferably Alkyldiphenyloxide Disulfonate (as 45%sol), Non-ionic surfactant preferably a mixture of ethoxylated linear fatty alcohols (as 65% sol), diacetone acrylamide, MMA monomer, 2-ethyl hexylacrylate monomer, HEMA, glacial methacrylic acid, potassium persulfate.

Another embodiment of the present invention is to provide a process for manufacture of polymer wherein the reactor charge comprises demineralized water, Anionic surfactant preferably AlkyldiphenyloxideDisulfonate (as 45%sol)Non-ionic surfactant preferably mixture of ethoxylated linear fatty alcohols as 65% sol and potassium persulfateto which said pre-emulsion is added.

Another embodiment of the present invention is to provide a process for manufacture of polymer whereinsaid digestion catalyst comprises demineralized water, sodium formaldehyde sulphoxlate, tertiary butyl hyderoperoxide, Non-ionic surfactant preferably a mixture of ethoxylated linear fatty alcohols 65% sol.
DETAILED DESCRIPTION OF THE INVENTION
As discussed hereinbefore, the present invention provides for a simple industrially facile process for the manufacture of a co-polymer of acrylics with incorporation of itaconic acid as one co-monomer, said co-polymer having glass transition temperature in the range between 21°C to 35°C, whereby the minimum film forming temperature is reduced in the range of 2-4°C. The slower rate of free radical polymerization of itaconic acid than acrylic acid coupled with delayed introduction (addition of Itaconic acid started after 2 hours of reaction) of Itaconic acid to the reaction ensures the presence of carboxylic acid from itaconic acid more onto the outer periphery of the polymer- making the same more hydrophilic and hence the polymer takes water as coalescent for formation of film. Inclusion of Itaconic acid minimum by 0.25% reduced the amount of coalescent (texanol) by 10% on polymer solids, thereby reducing the Volatile organic content of the paint.

It is thus significantly found by way of the present invention that:
a. Presence of itaconic acid 0.25% minimum lowers the MFFT of the acrylic copolymer by 2-4°C;
b. Itaconic acid 0.25 wt.% addition in pre-emulsion, only after 120 minutes (out of 240 minutes) of addition of pre-emulsion into the reactor, i.e. 120 minutes addition of pre-emulsion if does not contain itaconic acid, then only facilitates reduction of MFFT of the acrylic copolymer by 2-4°C.

In accordance with the process of the present invention the polymer particle using single stage free radical polymerization is formed whereby the addition of Itaconic acid when started only after 2 hours of reaction facilitated a co-polymer of pure acrylics with incorporation of itaconic acid as one co-monomer, having glass transition temperature measured in the range between 21°C to 35°C. Incorporation of itaconic acid through said process modification and when used in select wt.% amounts, is found to reduce minimum film forming temperature to a range of 2-4°C and favourably does not employ any coalescing and /or plasticizing agents for reducing MFFT of the dispersion of said polymer particle and neither employs any protective colloids to stabilize the dispersion. The polymerizable carboxylic acid preferably itaconic acid is added in the pre-emulsion with said process modification and subsequently polymerized.

Thus in the present invention one of the reactant (Itaconic acid) as the co-monomer is added after 2 hr of polymerization to the reaction vessel including the ingredients of MMA,EHA, itaconic acid with dispersing agents and catalystafter 2-hour pre-emulsion addition. The presence of itaconic acid at a level of 0.25%- 0.75 wt. %enables lowering of the MFFT by 2-4°C of the acrylic copolymer thus aiding reduction of the amount of coalescent (texanol) by 10% on polymer solids for addition in the dispersion, thereby reducing the volatile organic content of the paint/coating systems.

It was thus found by way of the present invention that Itaconic acid upon introduction in the reaction mixture after 2-hour pre-emulsion addition enables slower rate of free radical polymerization of itaconic acid than acrylic acid which possibly coupled with delayed introduction of Itaconic acid to the reaction ensures the presence of carboxylic acid groups of itaconic acid more onto the outer periphery of the polymer- making the same more hydrophilic which takes water as coalescent for formation of film. Itaconic acid addition is not related to any addition of neutralized itaconic acid or itaconic acid salt in the present process.
Example 1: Process Description

According to another embodiment of the present invention the following process steps were employed for the synthesis:
1. To the glass reactor wereaddeddemineralized water, anionic surfactant, non-ionic surfactant in sequence with the below mentioned quantities in reactor charge;
2. To a separate vessel (PE vessel), were added in sequence the ingredients, mentioned in monomer Pre-emulsion;
3. The reactor was heated to 80°C and 5% pre-emulsion into the reactor was added, followed by addition of Sodium bicarbonate, potassium persulphate solution and held for 10 minutes;
4. Add the remaining pre-emulsion over a period of 4 hours;
5. After completion of 45 minutes of pre-emulsion, Vinyl trimethoxy silane (VTMO) into the pre-emulsion was added, mix it and continue the addition and maintain 80°C throughout 4 hours
6. After completion of pre-emulsion, the temperature was brought down to 75°C and tertiary butyl hydroperoxide solution was added with non-ionic surfactant, and sodium formaldehyde sulphoxylate solution prepared separately over a period of 5 to 10 minutes as a separate feed, simultaneously;
7. The temperature for digestion was maintained for 1 hour;
8. The reactor was cooled to 30°C and the ingredients added mentioned in additives stage, mixed for 5 minutes and filter it with nylon cloth of 80 mesh size;
9. Similar experiments were carried out for different glass transition temperature using fox equation.

After synthesis using the above process, the resulting samples were characterizedas per the following details:
a. Characterization of Samples;
b. Minimum film forming temperature was measured using the instrument MFFT Bar (from MFFT Bar 60, from Rho point);
c. Glass transition temperature was measured using the instrument DSC Q10, from IA instruments

Example 2: CASE-1
Study range of itaconic acid was fixed from 0- 1%. When 0 wt.%, 0.25 wt.%, 0.55 wt.%,0.75 wt.% and 1 wt.% were studied, it was observed that the threshold limit was at 0.75 wt.% for reducing Minimum film forming temperature (MFFT). After which such reduction in minimum film forming temperature (MFFT) was no more realized. Hence the selective range is 0.25- 0.75 wt.%. Data on the same is as follows in the Table below:

Description MFFT °C
MAA(0.50)-IA(0.25) 23.6
MAA(0.50)-IA(0.55) 21.8
MAA(0.50)-IA(0.75) 20.2
MAA(0.50)-IA(1.0) 20.8
From the above table, it could be seen that 0.75 wt.% is the threshold limit and post 0.75 wt.% no effect was seen. Hence therequired rangefor the subsequent experiments was limited to 0.25% to 0.75 wt.%.

Example 2: CASE-2
A. 4 Set of experiments (with and without Itaconic acid) with variations in Glass transition temperature (Tg) were run with ingredients mentioned as in Table 1 and process mentioned in process description above,
B. Tg variations were done from 21°C to 35°C measured using Differential scanning calorimetry (DSC),
C. Variations of Minimum film forming temperature (MFFT) were measured for each set and arrived at the difference of MFFT in °C,
D. The results are illustrated under Table 2.

The following Table 1 states the % ingredients used for synthesis of polymer:
Exp1- involves ingredients along with itaconic acid where we observed reduction of minimum film forming temperature.
Exp2- involves ingredients without itaconic acid. This is the control sample (i.e. without Itaconic acid)

TABLE: 1
R.M. Description Exp 1
(wt.%) Exp 2
(wt.%)
Monomer Pre emulsion
DE MINERALISED WATER 22.39 22.39
Anionic surfactant
(AlkyldiphenyloxideDisulfonate (45%sol)) 0.40 0.40
Non-ionic surfactant
(Mixture of ethoxylated linear fatty alcohols 65% sol) 0.85 0.85
DIACETONE ACRYLAMIDE 0.22 0.22
MMA MONOMER 25.55 25.80
2-ETHYL HEXYL ACRYLATE MONOMER 20.25 20.25
HEMA 2.00 2.00
GLACIAL METHACRYLIC ACID 0.50 0.50
ITACONIC ACID 0.25 0.00
POTASSIUM PERSULPHATE 0.06 0.06
VTMO (to be added after 45 min) 0.50 0.50

Reactor Charge
DE MINERALISED WATER 21.19 21.19
Anionic surfactant
(AlkyldiphenyloxideDisulfonate (45%sol)) 0.20 0.20
Non-ionic surfactant
(Mixture of ethoxylated linear fatty alcohols 65% sol) 0.11 0.11
SODIUM BICARBONATE (COMM/LR) 0.20 0.20
POTASSIUM PERSULPHATE 0.12 0.12

Digestion Catalyst
DE MINERALISED WATER 0.50 0.50
SODIUM FORMALDEHYDE SULPHOXLATE 0.04 0.04
DE MINERALISED WATER 0.50 0.50
TERTIARY BUTYL HYDEROPEROXIDE 0.04 0.04
Non-ionic surfactant
(Mixture of ethoxylated linear fatty alcohols 65% sol) 0.06 0.06
DE MINERALISED WATER 0.80 0.80

Additives
Biocide 0.20 0.20
ADIPIC ACID DIHYDRAZIDE 0.11 0.11
Non-ionic surfactant
(Mixture of ethoxylated linear fatty alcohols 65% sol) 0.05 0.05
DE MINERALISED WATER 2.39 2.39
Defoamer 0.02 0.02
LIQUOR AMMONIA 0.50 0.50

Total 100.00 100.00

TABLE:2
Ingredients Tg
(DSC) °C MFFT (°C) Difference (°C) MFFT

SET -1 MAA(0.50)-IA(0.25)
(Exp-1) 18.8 20.2 1.7
MAA(0.50) (Exp-2) 21.1 21.9
SET -2 MAA(0.50)-IA(0.25)
(Exp-1) 27.9 26.1 1.2
MAA(0.50) (Exp-2) 28.1 27.3
SET-3 MAA(0.50)-IA(0.25)
(Exp-1) 36.1 31.3 2.1
MAA(0.50) (Exp-2) 34.1 33.4
SET-4 MAA(0.50)-IA(0.25)
(Exp-1) 37.2 37.1 3.3
MAA(0.50) (Exp-2) 35.2 40.4

Results:
From the above results, it is evident with increase in glass transition temperature, the lowering of MFFT is more. Which otherwise, need a coalescing agent (which contributes to volatile organic compound of the system).
This particular invention indicates addition of solid material instead of evaporating liquid to reduce MFFT of coating, thereby reducing the coalescent requirement.

Example 3: CASE 2

The effectiveness of grafting Itaconic acid on different layers of polymer particle was examined. Various experiments were run by taking the ingredients of Exp 1 above as illustrated under Table 1, except the stage of addition of Itaconic acid in pre-emulsion was varied.
Following Table 3 indicates the various stages in which itaconic acid addition was executed.
Exp 3- In this experiment, Itaconic acid was added to pre emulsion throughout the 4 hour;
Exp 4- In this experiment, Itaconic acid was added to pre emulsion throughout after 60 minutes of pre emulsion addition into the reactor;
Exp 5 - In this experiment, Itaconic acid was added to pre emulsion throughout after 120 minutes of pre emulsion addition into the reactor;
Exp 6 - In this experiment, Itaconic acid was added to pre emulsion throughout after 180 minutes of pre emulsion addition into the reactor;
Exp 7 - In this experiment, Itaconic acid was added to pre emulsion throughout after 240 minutes of pre emulsion addition into the reactor;
Exp 8 - In this experiment, Itaconic acid was added into the reactor before starting Pre emulsion addition.
All the other process instructions remained same.

Table 3 states the results achieved of minimum film forming temperature of the samples prepared using the above process variation. It is evident that reduction of minimum film forming temperature is highest in Experiment 5 where Itaconic acid is added into the reactor after 120 minutes of adding the rest of the pre-emulsion.

TABLE NO: 3
EXPERIMENT NUMBER ADDITION OF IA IN PRE-EMULSION MFFT (°C)
EXPERIMENT 3 Throughout 24.7
EXPERIMENT 4 AFTER I HR ADDITION 21.5
EXPERIMENT 5 AFTER II HR ADDITION 20.7
EXPERIMENT 6 AFTER III HR ADDITION 21.5
EXPERIMENT 7 AFTER IV HR ADDITION 22.1
EXPERIMENT 8 0 HR (along with Seed) 25.4

Hence, it was surprisingly found that presence of itaconic acid 0.25 wt.% minimum is required to lower the MFFT by 2-4°C of acrylic copolymer, that too only when addition of itaconic acid at 0.25 wt.% takes place in pre-emulsion, after 120 minutes (out of 240 minutes) of addition of pre-emulsion into the reactor, i.e. until 120 minutes addition of pre-emulsion in the reactor the same should be essentially free ofitaconic acid. Thus advantageously, the inclusion of Itaconic acid by 0.25 wt.% at select and at a particular stage of single stage thermal (radical) emulsion polymerization process aided reduction of the amount of coalescent (texanol) by 10% on polymer solids, thereby reducing the volatile organic content of the paint/ coating systems.

It is assumed that the process of surprisingly achieving the lowest minimum film forming temperature is made possible by way of the present advancement by pushing the carboxylic group present in itaconic acid more onto the outer periphery of the polymer particle using delayed addition technique based on addition in select wt.% amounts, which possibly makes the polymer particle more hydrophilic which takes water as coalescent for formation of film. Further no coalescing and /or plasticizing agents is employed in the present invention for reducing MFFT of the dispersion thatalso does not contain any protective colloids to stabilize the dispersion. The polymerizable carboxylic acid preferably itaconic acid is added in the pre-emulsion with said process modification and subsequently polymerized.