Claims:We Claim:
1. An oxidative cure aqueous hybrid polymer dispersion comprising:
alkyd modified acrylic resin/s as reaction product of
i) 40-70 wt.% of ethylenically unsaturated diacids and/ or anhydride modified fatty acid based acrylic resin having acid value 100-130 mg-KOH/g, and
ii) 30-60 wt.% of fatty acid containing alkyd resin of hydroxyl value 80-130 mg-KOH/g and acid value less than 5 mg-KOH/g.
2. The oxidative cure aqueous hybrid polymer dispersion as claimed in claim 1 wherein said alkyd modified acrylic resin is condensation polymerized acrylic: alkyd hybrid resin in preferable ratio of 45:55 that is dispersed by including amine neutralizer and organic solvent with said resin preferably being ambient and auto-oxidative cure/ auto cross linking type.
3. The oxidative cure aqueous hybrid polymer dispersion as claimed in claim 1 wherein said component (i) ethylenically unsaturated diacids and/ or anhydride modified fatty acid based acrylic resin of acid value 100-130 mg-KOH/g is radical copolymerized product of monomers comprising:
a) 20 to 80 wt.% of at least one unsaturated fatty acid including DCOFA, SOFA, POFA, TOFA,
b) 2 to 20 wt%. at least one unsaturated monomer containing at least one acid group or group capable of forming an acid functionality selected at least one from fumaric acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride,
c) 1 to 10 wt.% acrylic and vinylic monomers containing at least one acid group selected from methacrylic acid, acrylic acid;
and is preferably DCOFA and/or SOFA based maleic anhydride (MA) modified acrylic resin adapted for improved durability and gloss.
4. The oxidative cure aqueous hybrid polymer dispersion as claimed in claim 1 wherein said component (ii) is DCOFA/SOFA containing alkyd resin having an acid number from less than 5 mg KOH/g, Hydroxy number 80-130 mg-KOH/g and an oil length of the resin between 30 and 50%, the said alkyd reaction product of (a)1 mol % to 100% of isophthalic acid, 1 mol % to 100 % of benzoic acid and 1 mol % to 100 mol % of fatty acid, or a mixture thereof, reacted with (b) a polyol mixture comprising at least one diol and at least one polyol having at least three hydroxyl group
5. The oxidative cure aqueous hybrid polymer dispersion as claimed in claims 1-4 wherein said auto-oxidatively cross-linkable resin based waterborne dispersion of acrylic-alkyd hybrid polymer resin has significant higher molecular weight (ranging from 10000 to 45000) stabilized in aqueous phase in said dispersion and is free of any external emulsifying agent or surfactant and having viscosity in the levels of 200 to 500 KU.
6. The oxidative cure aqueous hybrid polymer dispersion as claimed in claims 1-5 is stable for 6 months - 1.5 year and adapted for as an oxidative/auto oxidative cross-linked thermoset suitable for a coating/ paint composition with highly improved mechanical, chemical and salt spray performance as compared to thermoplastic binder with difficult to achieve film hardness, impact, salt spray and chemical resistance performance.
7. The oxidative cure aqueous hybrid polymer dispersion as claimed in claims 1-6 having low VOC content of less than 20 % and narrow broader particle size distribution (unimodal) of 70-250 nm favoring high gloss on phosphate treated mild steel substrate when applied by spray and after completing 7 days of oxidative curing.
8. The oxidative cure aqueous hybrid polymer dispersion as claimed in claims 1-7 suitable for pigmented coating/ paint composition for application on metals resulting in excellent air drying performance in presence of metallic drier, in excellent finish appearance of gloss level @60 Deg is 80-80 units on mild steel substrate and after completing 7 days of oxidative curing, and excellent anti corrosive performance (salt spray resistance more than 500 Hrs) without addition of any anti-corrosive agents; and
also suitable for pigmented coats for direct to metal application resulting in excellent durability (80% gloss retention after 300 Hrs of exposure in QUV A), excellent Diesel dip resistance (No defects in paints film of the MS panel after exposure to dip test of Diesel solution for 24Hrs).
9. A process for manufacturing oxidative cure aqueous hybrid polymer dispersion as claimed in claims 1-8 comprising the steps of
i) providing 40-70% of ethylenically unsaturated diacids and/ or anhydride modified fatty acid based acrylic resin of acid value 100-130 mg-KOH/g, and
ii) providing 30-60% of fatty acid containing alkyd resin preferably DECOFA/SOFA containing alkyd resin of hydroxyl value 80-130 mg-KOH/g and acid value less than 5 mg-KOH/g; and
(iii) condensation polymerizing to react hydroxyl group in alkyd resin and carboxylic acid functional acrylic resin to obtain alkyd modified acrylic resin followed by dispersing the resin in water to obtain waterborne dispersion of the same.
10. A process for manufacturing oxidative cure aqueous hybrid polymer dispersion as claimed in claim 9 wherein said alkyd modified acrylic resin is obtained by addition of amine neutralizer with water that stabilizes said resin of molecular weight ranging from 10000 to 45000 free of any external emulsifying agent or surfactant.
11. A process for manufacturing oxidative cure aqueous hybrid polymer dispersion as claimed in claims 9-10 wherein said step (i) of providing ethylenically unsaturated diacids and/ or anhydride modified fatty acid based acrylic resin of acid value 100-130 mg-KOH/g comprises the following steps
(a) charging 10-20 wt.% (dehydrated castor oil) DCO fatty acid;
(b) preparing the acrylic monomix with initiator by using acrylic monomers including Methyl methacrylate (MMA), 2-Ethylhexyl acrylate (2-EHA), Methacrylic acid (MAA) in the levels of 20-60 wt.%, Maleic anhydride in the levels of 3-6 wt.%, initiator in the levels of 1-2 wt.%;
(c) increasing the temperature of charge (a) upto 140 ?C followed by acrylic monomix addition within a period of 4.5-5 Hrs. followed by holding the charge after complete addition of monomer mix for 1 Hrs. followed by further adding DTAP-II (PLEASE EXPAND) as a chaser catalyst for complete digestion that was then cooled up to 120 Deg.C and thinned by organic solvent including O-Xylene (39.36) for storing the resulting ethylenically unsaturated diacids and/ or anhydride modified fatty acid based acrylic resin of acid value 100-130 mg-KOH/g preferably in stainless steel container.
12. A process for manufacturing oxidative cure aqueous hybrid polymer dispersion as claimed in claims 9-10 wherein said step (ii) of providing fatty acid containing alkyd resin of hydroxyl value 80-130 mg-KOH/g and acid value less than 5 mg-KOH/g comprises the following steps
(a) charging 30-50 wt.% of (dehydrated castor oil) DCO fatty acid/ SOFA fatty acid, 25-32 wt.% polyol or mixtures thereof including Trimethylol propane (TMP), Neopentyl Glycol (NPG), Methyl Propane Diol (MPD), 10-45 wt.% Isopthalic Acid with or without Benzoic acid 0-4 wt.%, Ortho xylene 0-4 wt.%, 0.1-0.15 wt.% Dibutyl tin dioxide (DBTO) catalyst and stirring in presence of inert gas followed by slowly heating to 180 °C for 1 Hr with periodical increase of temperature by 10 °C /Hr followed by holding at 240°C until the acid value reaches to about 3 mg/KOH and hydroxyl value reaches between 80-130 mg-KOH/g;
(b) adding organic solvent including o-xylene 1-4 wt% to the mixture of step (i) followed by subsequently cooling up to 100°C.

13. A process for manufacturing oxidative cure aqueous hybrid polymer dispersion as claimed in claims 9-10 wherein said step (iii) of condensation polymerizing to react hydroxyl group in alkyd resin and said carboxylic acid value based acrylic resin to obtain alkyd modified acrylic resin comprises the following steps:
(a) charging 40-70 wt. % of said acrylic resin (60% on solids) and 30-60 wt.% of alkyd resin (80% on solids) followed by raising temperature to 140 ?C,
(b) applying vacuum to remove organic solvent completely followed by measuring the acid value after every 30 min interval until acid value of 45-70 preferably 45-51 mg-KOH/ gm is reached when heating is stopped followed by adding butyl cellosolve immediately and cooled to 70 ?C;
(c) adding liq. Ammonia and demineralized water mixture for dispersing said hybrid polymer in water for ?1 Hr at 70 ?C to result in ? 40 % waterborne alkyd acrylic hybrid dispersion in water suitable for paint formulations.

Dated this the 17th Day of January, 2022 Anjan Sen
Of Anjan Sen and Associates
(Applicants Agent)
IN/PA-199
, Description:FIELD OF INVENTION
The present invention relates to oxidative cure aqueous hybrid polymer dispersion and acrylic-alkyd hybrid polymeric resin comprising the same, which acrylic-alkyd hybrid polymeric resin is a polycondensation product of acrylic base functional resin with hydroxyl terminated fatty acid base alkyd components that is further converted into a water dispersion to find end application for direct to metal application having excellent salt spray resistance (>500 Hrs.), excellent gloss retention (75% after 300 hrs. exposure of QUV).

BACKGROUND ART
In past few decades, considerable effort has been taken by various industries to develop low or Zero VOC (volatile organic compounds) base waterborne binder/coating. Regulations to limit the VOC of industrial coatings have encouraged research and development to explore new technologies directed to reducing Solvent emissions from industrial Solvent-based coatings operations at various metals coating applications. However, while the move to reduce organic solvent based for health and safety benefits, these low VOC compositions must still meet or exceed the performance standard expected from solvent based compositions.
The alkyd component of the hybrid systems advantageously influences the open time, gloss, flow, haze and substance wetting of the final product; whereas the acrylate segments advantageously influence the early blocking resistance, outdoor durability, and reduces yellowing. In addition to that Acrylic-alkyd hybrid dispersion has improved film forming properties due to low glass transition temperature of the alkyd component. However, the presence of alkyd also results in critical problems, like soft film, higher drying time etc. In an attempt to address such concern, urethane modification of water based acrylic-alkyd hybrid systems received considerable attentions.
References are drawn to the following wherein US 2004/0054074 A1 relates to preparation of acrylic-modified alkyd resin comprising the Steps a) preparing a Sulfonated alkyd resin product and then b) preparing an acrylated fatty acid product separately and then reaction of the product of step a) and the product of Step b) under appropriate polymerization conditions, and for preparing a waterborne composition. Here sulphonates moieties and carboxylic acid salts used to stabilized the polymer in aqueous phase.
U.S. 3,666,698 relates to an alkyd resin prepared by reacting an oil containing an olefinically unsaturated carboxylic fatty acid having at least 10 carbon atoms, with more than 30 percent but less than 45 percent of phenylindane dicarboxylic acid and a sufficient amount of a trihydroxy polyol to provide an OH : COOH ratio in the range from about 1.5 to about 2.5 and a sufficient quantity of a benzene tribasic acid or anhydride to react with from 70 to about 80 percent of the hydroxy groups present to form a water-dispersible alkyd resin capable of air drying to a hard, glossy, durable finish without baking.
US4720522 describes water reducible alkyd vinyl copolymer resins. The copolymer dispersions are prepared using, more particularly, copolymers obtained by solution polymerization of (metha) acrylates and unsaturated fatty acids. These copolymers requires large amount of solvents for processing and thereafter to obtain the dispersions. Removal of such high amounts of solvents from dispersions can create safety and economic problems.
US 5,378,757 disclosed a water-dissipatable alkyd resin containing a sulfonate group. The alkyd resin is prepared by reacting at least one monoglyceride, a polycarboxylic acid, and a polyol sulfomonomer adduct containing at least D- one sulfonate group. The alkyd resin is useful to prepare cross-linked coatings such as obtained with oil based.
U.S. 3,494,882 is directed to a water reducible paint capable of forming a high gloss coating which comprises an initial emulsion in water based on initial emulsion of an air drying unsaturated fatty acid modified polyester said polyester having an acid value of 0-30 and being insoluble in ammonia or amine water, a non-ionic or anionic surfactant, pigments dispersed in the initial emulsion, polymeric synthetic latex prepared by polymerization of ethylenically unsaturated monomers in water in the presence of free radical producing surfactants and blended with said initial emulsion and pigments. Said polymeric latex being already in a copolymerized state cannot be said to have any kind of covalent interaction between the alkyd resin and the acrylic group
U.S. 3,434,987 relates to aqueous stoving varnishes based on amine salts of semesters of hydroxy group containing fatty acid modified alkyd resins comprising salts of semi-esters of water insoluble alkyd resins, which does not teach any acrylic modification of the alkyd resin.
US4116903 relates to synthesis of alkyd based on trimellitic anhydride compound and further neutralization of acid and stabilization in water. This Alkyd having acid value is 43.3 mg/KOH. Its emulsion made by using alkyd as an emulsifier, and there is no grafting of acrylic monomer on the alkyd component.
US3001961 tells us alkyd made by this prior art having acid value 16 to 24 (here specially mention that acid value should not be less than 5 mg/KOH), vinyl monomer were co-polymerize with alkyd component at elevated temperature, no clear evidence of free radical grafting of vinyl on alkyd backbone. It was mandatory that 48 hrs. processing in ball of resin with pigments to get a stable dispersion. Its mechanically stabilized binder and final Molecular wt. 300-6000
EP000087 relates to synthesis of pure alkyd emulsion and one of the molecules is polyxoy ethylene molecules, and wherein sulfosuccinate & polyvinyl alcohol used as additional RM to make emulsion in aqueous phase.
Reference is also drawn to J. of Korean Oil Chemists Society, Vol. 20, No. 4 December 2003, 372-376, that teaches water soluble cutting fluid additives derived from the thermal reaction products of unsaturated fatty acids (dehydrated Castrol oil fatty acid-DCOFA) with acrylic acids and maleic anhydride, but does not teach any dehydrated Castrol oil fatty acid (DCOFA) and maleic anhydride grafted acrylic as a reactive component.
US4111871A teaches oil-modified alkyd resin composition comprising: (A) 50 to 80% by weight of an oil-modified alkyd resin which is modified with a fatty acid containing at least 65% by weight of linoleic acid and/or linolenic acid and has an oil length of 40 to 70%; and (B) 50 to 20% by weight of an acrylate and/or methacrylate which is a monoester of an alcohol having from 2 to 20 carbon atoms and acrylic acid or methacrylic acid, and though teaches dehydrated castor oil component as linoleic acid, but is based on maleic anhydride modified alkyd resin that reacts with hydroxyacrylates.
ICE 2007, International Coatings Expo: Clean-Lean-Green: Innovative Solutions for the Global Coatings Community, Toronto, ON, Canada, Oct. 3-5, 2007 (2007), 92/1-92/58, teaches NMR analysis of acrylic-alkyd hybrid resins using one-dimensional and two-dimensional NMR techniques whereby acrylic-alkyd hybrid resins have been synthesized from glycerol, phthalic anhydride, tetrahydrophthalic anhydride, soybean oil, Me methacrylate, Bu acrylate, methacrylic acid, and vinyltrimethoxysilane to investigate the mechanism and specific grafting sites of soybean oil based alkyds modified with acrylic systems.
US6333378 B1 is directed to a water-based latex of an acrylic-modified waterborne alkyd or uralkyd dispersion in water. The acrylic-modified waterborne alkyd or uralkyd is a hybrid resin prepared by the polymerization of at least one latent oxidatively-functional (LOF) acrylic monomer in the presence of a waterborne alkyd or uralkyd. Alternatively, the acrylic-modified waterborne alkyd or uralkyd is a hybrid resin prepared by shearing a mini-emulsion based on a solvent-borne alkyd or uralkyd dissolved in at least one LOF acrylic monomer. Preparation of the latexes are achieved by emulsion polymerization of at least one latent oxidatively-functional acrylic monomer in the presence of a waterborne alkyd or uralkyd whereby the latent oxidative functionality of the acrylic polymer survives polymerization. Water-based latexes were also prepared by polymerizing a sheared mini-emulsion based on a solvent-borne alkyd or uralkyd dissolved in at least one LOF acrylic monomer such that the latent oxidative functionality of the acrylic polymer survives polymerization. Such acrylic-modified waterborne alkyd or uralkyds are useful in a variety of coating compositions wherein the binder is developed through emulsion process with the help of surfactants usually associated with poor salt spray and humidity performance on direct to metal applications, and not through dispersion methodology. This prior patent has used the ethylenic unsaturation of fatty acid for grafting the acrylic moiety on alkyd backbone to form a high molecular weight latex and is thus a complex manner of leading to a macromolecular network that is not through condensation polymerization that does not allow much higher loading of alkyd moiety to satisfy gloss requirements, hardness etc. Further this prior patent teaches thermoplastic binder through which it’s very difficult to get the performance like film hardness, impact performance, Salt spray and very high chemical resistance, which thermoplastic binder is not a oxidative cross-linked thermoset.
It is thus a need in the art to provide for suitable and improved alkyd modified acrylic resin that would overcome the known associated problems acrylic-alkyd systems of low gloss, higher drying time and poor salt spray resistance as the same is usually built through free radical polymerization of acrylic monomers with unsaturated alkyd polymers resulting in such slow drying time, higher tack free time and low gloss due to less availability of the unsaturated double bond during oxidative curing.

OBJECTS OF THE INVENTION
It is thus the primary object of the present invention to provide for acrylic-alkyd hybrid resin and oxidative cure waterborne acrylic-alkyd hybrid dispersions thereof, said acrylic-alkyd hybrid resin that would be a polycondensation product of acrylic base functional resin with hydroxyl terminated fatty acid containing alkyd components.
It is another object of the present invention to provide for said acrylic-alkyd hybrid resin that would be further convertible to a water dispersion meeting suitable viscosity requirements to find end application for direct to metal application giving excellent salt spray resistance (>500 Hrs.), excellent gloss retention (75% after 300 hrs. exposure of QUV).
It is yet another object of the present invention to provide for said acrylic-alkyd hybrid resin dispersion that would enable direct to metal application without priming the substrate to benefit industrial usage and also to enable a self-primer as 2 top coat for metal application under semi-gloss category.
It is another object of the present invention to provide for said acrylic-alkyd hybrid resin dispersion as a 1K waterborne system for direct to metal application having high gloss (@60 -75), Excellent gloss retention (75% GR after 300 hrs and excellent corrosion resistance (250 Hrs).
It is yet another object of the present invention to provide for a process to develop said binder that would not require any surfactant to attain the dispersion as surfactant stabilized binders usually have associated with poor salt spray and humidity performance on direct to metal applications.
It is still another object of the present invention to provide for method that would employ a simpler approach to prepare macromolecular network through condensation polymerization through which acrylic-alkyd hybrid resin would be attained enabling higher loading of alkyd moiety based on the requirement of gloss, hardness etc., and not involve any ethylenic unsaturation of fatty acid for grafting the acrylic moiety on alkyd backbone to form a high molecular weight latex.
It is yet another object of the present invention to provide for oxidative cross-linked thermoset which can give very high mechanical, chemical and salt spray performance unlike a thermoplastic binder based on which it is very difficult to get the performance like film hardness, impact performance, Salt spray and very high chemical resistance.

SUMMARY OF THE INVENTION
Thus according to the basic aspect of the present invention there is provided an oxidative cure aqueous hybrid polymer dispersion comprising:
alkyd modified acrylic resin/s as reaction product of
i) 40-70 wt.% of ethylenically unsaturated diacids and/ or anhydride modified fatty acid based acrylic resin having acid value 100-130 mg-KOH/g, and
ii) 30-60 wt.% of fatty acid containing alkyd resin of hydroxyl value 80-130 mg-KOH/g and acid value less than 5 mg-KOH/g.
According to another preferred aspect of the present invention there is provided said oxidative cure aqueous hybrid polymer dispersion wherein said alkyd modified acrylic resin is condensation polymerized acrylic: alkyd hybrid resin in preferable ratio of 45:55 that is dispersed by including amine neutralizer and organic solvent with said resin preferably being ambient and auto-oxidative cure/ auto cross linking type.
Preferably said oxidative cure aqueous hybrid polymer dispersion is provided wherein said component (i) ethylenically unsaturated diacids and/ or anhydride modified fatty acid based acrylic resin of acid value 100-130 mg-KOH/g is radical copolymerized product of monomers comprising:
a) 20 to 80 wt.% of at least one unsaturated fatty acid including DCOFA, SOFA, POFA, TOFA,
b) 2 to 20 wt%. at least one unsaturated monomer containing at least one acid group or group capable of forming an acid functionality selected at least one from fumaric acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride,
c) 1 to 10 wt.% acrylic and vinylic monomers containing at least one acid group selected from methacrylic acid, acrylic acid;
and is preferably DCOFA and/or SOFA based maleic anhydride (MA) modified acrylic resin adapted for improved durability and gloss.
Said oxidative cure aqueous hybrid polymer dispersion is provided wherein said component (ii) is DCOFA/SOFA containing alkyd resin having an acid number from less than 5 mg KOH/g, Hydroxy number 80-130 mg-KOH/g and an oil length of the resin between 30 and 50%, the said alkyd reaction product of (a)1 mol % to 100% of isophthalic acid, 1 mol % to 100 % of benzoic acid and 1 mol % to 100 mol % of fatty acid, or a mixture thereof, reacted with (b) a polyol mixture comprising at least one diol and at least one polyol having at least three hydroxyl group
More preferably, said oxidative cure aqueous hybrid polymer dispersion is provided wherein said auto-oxidatively cross-linkable resin based waterborne dispersion of acrylic-alkyd hybrid polymer resin has significant higher molecular weight (ranging from 10000 to 45000) stabilized in aqueous phase in said dispersion and is free of any external emulsifying agent or surfactant and having viscosity in the levels of 200 to 500 KU.
According to another preferred aspect of the present invention there is provided said oxidative cure aqueous hybrid polymer dispersion that is stable for 6 months - 1.5 year and adapted for as an oxidative/auto oxidative cross-linked thermoset suitable for a coating/ paint composition with highly improved mechanical, chemical and salt spray performance as compared to thermoplastic binder with difficult to achieve film hardness, impact, salt spray and chemical resistance performance.
Preferably said oxidative cure aqueous hybrid polymer dispersion is provided having low VOC content of less than 20 % and narrow broader particle size distribution (unimodal) of 70-250 nm favoring high gloss on phosphate treated mild steel substrate when applied by spray and after completing 7 days of oxidative curing.
More preferably said oxidative cure aqueous hybrid polymer dispersion is provided suitable for pigmented coating/ paint composition for application on metals resulting in excellent air drying performance in presence of metallic drier, in excellent finish appearance of gloss level @60 Deg is 80-80 units on mild steel substrate and after completing 7 days of oxidative curing, and excellent anti corrosive performance (salt spray resistance more than 500 Hrs) without addition of any anti-corrosive agents; and
also suitable for pigmented coats for direct to metal application resulting in excellent durability (80% gloss retention after 300 Hrs of exposure in QUV A), excellent Diesel dip resistance (No defects in paints film of the MS panel after exposure to dip test of Diesel solution for 24Hrs).
According to another aspect of the present invention a process for manufacturing oxidative cure aqueous hybrid polymer dispersion is provided comprising the steps of
i) providing 40-70% of ethylenically unsaturated diacids and/ or anhydride modified fatty acid based acrylic resin of acid value 100-130 mg-KOH/g, and
ii) providing 30-60% of fatty acid containing alkyd resin preferably DECOFA/SOFA containing alkyd resin of hydroxyl value 80-130 mg-KOH/g and acid value less than 5 mg-KOH/g; and
(iii) condensation polymerizing to react hydroxyl group in alkyd resin and carboxylic acid functional acrylic resin to obtain alkyd modified acrylic resin followed by dispersing the resin in water to obtain waterborne dispersion of the same.
Preferably, in said process for manufacturing oxidative cure aqueous hybrid polymer dispersion said alkyd modified acrylic resin dispersion is obtained by addition of amine neutralizer with water that stabilizes said resin of molecular weight ranging from 10000 to 45000 free of any external emulsifying agent or surfactant.
According to another preferred aspect of the present invention there is provided a process for manufacturing oxidative cure aqueous hybrid polymer dispersion wherein said step (i) of providing ethylenically unsaturated diacids and/ or anhydride modified fatty acid based acrylic resin of acid value 100-130 mg-KOH/g comprises the following steps
(a) charging 10-20 wt.% (dehydrated castor oil) DCO fatty acid;
(b) preparing the acrylic monomix with initiator by using acrylic monomers including Methyl methacrylate (MMA), 2-Ethylhexyl acrylate (2-EHA), Methacrylic acid (MAA) in the levels of 20-60 wt.%, Maleic anhydride in the levels of 3-6 wt.%, initiator in the levels of 1-2 wt.%;
(c) increasing the temperature of charge (a) upto 140 ?C followed by acrylic monomix addition within a period of 4.5-5 Hrs. followed by holding the charge after complete addition of monomer mix for 1 Hrs. followed by further adding DTAP-II (PLEASE EXPAND) as a chaser catalyst for complete digestion that was then cooled up to 120 Deg.C and thinned by organic solvent including O-Xylene (39.36) for storing the resulting ethylenically unsaturated diacids and/ or anhydride modified fatty acid based acrylic resin of acid value 100-130 mg-KOH/g preferably in stainless steel container.

Preferably in said process for manufacturing oxidative cure aqueous hybrid polymer dispersion said step (ii) of providing fatty acid containing alkyd resin of hydroxyl value 80-130 mg-KOH/g and acid value less than 5 mg-KOH/g comprises the following steps
(a) charging 30-50 wt.% of (dehydrated castor oil) DCO fatty acid/ SOFA fatty acid, 25-32 wt.% polyol or mixtures thereof including Trimethylol propane (TMP), Neopentyl Glycol (NPG), Methyl Propane Diol (MPD), 10-45 wt.% Isopthalic Acid with or without Benzoic acid 0-4 wt.%, Ortho xylene 0-4 wt.%, 0.1-0.15 wt.% Dibutyl tin dioxide (DBTO) catalyst and stirring in presence of inert gas followed by slowly heating to 180 °C for 1 Hr with periodical increase of temperature by 10 °C /Hr followed by holding at 240°C until the acid value reaches to about 3 mg/KOH and hydroxyl value reaches between 80-130 mg-KOH/g;
(b) adding organic solvent including o-xylene 1-4 wt% to the mixture of step (i) followed by subsequently cooling up to 100°C.

More preferably in said process for manufacturing oxidative cure aqueous hybrid polymer dispersion said step (iii) of condensation polymerizing to react hydroxyl group in alkyd resin and said carboxylic acid value based acrylic resin to obtain alkyd modified acrylic resin comprises the following steps:
(a) charging 40-70 wt. % of said acrylic resin (60% on solids) and 30-60 wt.% of alkyd resin (80% on solids) followed by raising temperature to 140 ?C,
(b) applying vacuum to remove organic solvent completely followed by measuring the acid value after every 30 min interval until acid value of 45-51 mg-KOH/ gm is reached when heating is stopped followed by adding butyl cellosolve immediately and cooled to 70 ?C;
(c) adding liq. Ammonia and demineralized water mixture for dispersing said hybrid polymer in water for ?1 Hr at 70 ?C to result in ? 40 % waterborne alkyd acrylic hybrid dispersion in water suitable for paint formulations.

DETAILED DESCRIPTION OF THE INVENTION
As discussed hereinbefore, the present invention provides for an oxidative cure preferably ambient oxidative cure water based acrylic-alkyd hybrid polymeric resin as aqueous polymer dispersion for high gloss water based paint application for metal substrate.
Said ambient oxidative cure acrylic-alkyd hybrid polymers for high gloss water based paint application on metal substrate comprises ethylenically unsaturated polyacid and/or anhydride grafted fatty acid based acrylic base functional resin polycondensed with hydroxyl terminated fatty acid alkyd components;
According to a preferred aspect said oxidative cure acrylic-alkyd hybrid polymers comprising 30-60% of fatty acid containing alkyd modified with 40-70% of ethylenically unsaturated diacids and/ or anhydride modified fatty acid based acrylic resin, which hybrid polymers enabling to achieve a stable aqueous polymer dispersion has final acid value 45-70 mg-KOH/g;
A stable (stable for 6 months-1 yr or more without any gel formation or change of viscosity) waterborne Alkyd-Acrylic hybrid dispersion, free of any emulsifier, could be thus achieved comprising hybrid polymers of ethylenically unsaturated polyacid and/or anhydride grafted fatty acid acrylic based acrylic resin polycondensed with hydroxyl terminated fatty acid base alkyd components, said hybrid polymers enabling waterborne dispersion by neutralization of their acid functionality preferably by liquor ammonia.

Most preferably, ambient oxidative cure acrylic-alkyd hybrid polymers comprise polymers of dehydrated Castor oil fatty acid (DCOFA) modified alkyd, and, ethylenically unsaturated polyacid and/or anhydride and dehydrated Castor oil fatty acid (DCOFA) grafted acrylic, that achieves said water dispersible acrylic-alkyd hybrid polymers;

Said ethylenically unsaturated polyacid and/or anhydride successfully grafted on acrylic segment helps to achieve high grafting of acrylic segment on the alkyd in alkyd modified acrylic resin via condensation polymerization without using any external emulsifying agents, vis-à-vis, prior known knowledge on acrylic polymer that builds up through free radical polymerization of acrylic monomers with unsaturated alkyd polymers resulting slow drying time, higher tack free time and low gloss due to less availability of the unsaturated double bond during oxidative curing.

For the first time it is as per the significant finding of the present invention, it could be demonstrated that grafting of preferably DCOFA in the acrylic backbone has a remarkable effect on final gloss of the paint, with the concentration of dehydrated castor oil fatty acid (DCOFA) and maleic anhydride (MA) in acrylic backbone that strike a balance in such a way to achieve excellent gloss without hampering the glass transition temperature.

Advantageously, said water based acrylic-alkyd hybrid dispersion provides for excellent diesel dip resistance, mechanical performance, salt spray resistance (>500 Hrs.) and gloss retention (80% after 300 hrs. exposure of QUV).

One aspect of the present invention is a water-based dispersion of an acrylic-modified alkyd resin. The acrylic modified alkyd dispersion involving said resins, which while on one hand in involving the alkyd resin may advantageously form cross-linked film on exposure to oxygen would also have modified drying time corrected by acrylic modification of the said resin. Further to the aforesaid, it is also imperative to provide for said acrylic modified alkyd resin that are water dispersible and subsequently free from hazardous solvents like MTO, Xylene, Butyl Acetate etc. by so as to remarkably reduce organic solvent requirements like IPA, Dowanol PM, Butyl Cellosolve etc. while forming final coatings.
The present invention thus provides an ambient oxidative cure composition comprising an acrylate functionalized alkyd resin, at least one drier, and an organic solvent. In a preferred embodiment of the present invention, an oxidative cure composition containing 30-60% of alkyd modified with 40-70% of ethylenically unsaturated diacids and/ or anhydride modified fatty acid based acrylic resin achieves a stable dispersion having final acid value 45-70 mg-KOH/g. The stable waterborne binder having acrylic components which gives excellent chemical resistance and weather ability and hardness. Similarly, the alkyd components give high gloss and flexibility due to select doses of DECO fatty acid in the same polymer. Here alkyd which undergoes oxidative polymerization in presence of metallic drier further builds the molecular weight while formation of film and enhance the properties like gloss, hardness, solvent resistance.
It is widely reported in literature that water based acrylic-alkyd hybrid systems can successfully be applied in metal applications for enamels, automotive, DTM etc. However, water based acrylic-alkyd hybrid dispersion was associated with low gloss, higher drying time and poor salt spray.
The Applicants thus could demonstrate for the first time that condensation reaction preferably between dehydrated Castor oil fatty acid (DCOFA)/SOFA based alkyd of hydroxyl value 80-130 mg-KOH/g and acid value (AV) less than 5 mg-KOH/g, and, ethylenically unsaturated polyacid and/or anhydride (MA-maleic anhydride) & dehydrated Castor oil fatty acid (DCOFA) grafted acrylic could help achieve water dispersible acrylic-alkyd hybrid polymers. Through such condensation reaction successful grafting of MA in the acrylic segment took place and high grafting of acrylic segment in the acrylic-alkyd hybrid system could be achieved without using any external emulsifying agents. The hurdle in the art could be thus overcome where it is known that acrylic polymer that is usually built through free radical polymerization of acrylic monomers with unsaturated alkyd polymers results in slow drying time, higher tack free time and low gloss due to less availability of the unsaturated double bond during oxidative curing.
Also, from the prior arts it was known that normal acrylic-alkyd hybrid emulsion or dispersion has low gloss on application and to overcome the issue either they have increased the alkyd content in the final hybrid or through uralkyd formation. Thus, by way of the present invention it could be demonstrated for the first time that the grafting of DCOFA in the acrylic backbone has a remarkable effect on final gloss of the paint. It is known that even with high concentration of acrylic in the final dispersion one can achieve very high gloss without compromising the drying time. But the concentration of DCOFA and ethylenically unsaturated diacids and/ or anhydride, preferably MA, in acrylic backbone are balance in such a way to achieve excellent gloss without hampering the glass transition temperature Glass Transition Range (-20 °C to 30 °C). Hybrid resins involving SOFA other than DCOFA gives even better gloss but hardness will be slightly on the lower side. While both DCOFA and MA in the acrylic backbone reflects in the acid value but large excess of DCOFA giving desired acid value causes loss of mechanical performance.
The desirable glass transition temperature is not so critical but it is desirable to have glass transition temperature in the range of -20 °C to -70 °C.
Apart from that, it is also shown that the present water based acrylic-alkyd hybrid dispersion enabled excellent diesel dip resistance, mechanical performance, salt spray resistance (>500 Hrs.) and gloss retention [80% after 300 hrs. exposure of QUV (QUV is accelerated weathering test (ASTM D4329] could be achieved.
EXAMPLES:
Stage-1) Synthesis of Hydroxyl Functional Alkyd resin (80% in O-xylene), i.e. component (ii) of the hybrid polymer:
All ingredients dehydrated castor oil (DCO) oil fatty acid /SOFA 44.18, Trimethylol propane 26.89, Isopthalic Acid 22.09, Benzoic acid 2.88, Ortho xylene 3.86, DBTO 0.10 were charged in the four-neck flask equipped with mechanical stirrer, nitrogen purging assembly, dean stark apparatus. This mixture was slowly heated to 180 °C for 1 Hr and periodically increased temperature by 10 °C /Hr. and hold at 240°C until the acid value reaches to about 3 mg/KOH, and hydroxyl value 110 mg/KOH. After reaching desire acid value add o-xylene 19.2 and subsequently the batch was cooled to up to 100°C and filtered for for storage.
Table 1:
Ingredients and its variants that works in the given wt.% range to give the desired hydroxyl value and acid value of fatty acid containing alkyd resin Wt.%
Dehydrated castor oil fatty acid (DCO), soyabean oil fatty acid (SOFA) 30-50
Polyol mixture, Trimethylol propane or mixtures of TMP, Neopentyl glycol (NPG), Methyl Propane Diol (MPD) 25-32
Isopthalic Acid 10-45
Benzoic acid 0-4
Ortho xylene, Mineralise turpentine oil (MTO) 0-4
Dibutyl tin dioxide (DBTO) 0.1-0.15
Total 100

Stage-2) Synthesis of Dehydrated castor Oil (DCO)/ Soyabean Oil fatty acid (SOFA)/ Palm Oil Fatty acid (POFA), Tall Oil Fatty Acid (TOFA) grafted Acrylic Components (60% in O-xylene) which is ethylenically unsaturated diacids and/ or anhydride modified fatty acid based acrylic resin of acid value 100-130 mg-KOH/g, i.e. component (i) of the hybrid polymer:
Charge (Dehydrated castor oil) DCO fatty acid 12.13 in to the reactor, simultaneously prepared the acrylic monomix with DTAP (Di-tertiary amyl peroxide) as initiator by using Methyl methacrylate (MMA) 24.87, 2-EHA 15.77G (2-Ethylhexyl acrylate), Methacrylic acid (MAA) 3.51, Maleic anhydride 3.03 DTAP 1.21. Increase the temperature of batch up to 140 Deg. C and then start addition of Monomix within a period of 4.5 Hrs to 5 Hrs. After complete addition of monomer mix hold this batch for 1 Hrs. and then add DTAP-II 0.12 as a chaser catalyst. After complete digestion cool this batch up to 120 ?C and thinned by using O-Xylene (39.36) and stored in Stainless Steel Container. The acid value attained is 111 mg-KOH/gm. Based on the ingredients wt.% range as below the desired acid value levels can change to be within the levels of 100-130 mg-KOH/g.
Table 2:
Ingredients including their variants as scoped that works in the given wt.% range to give the desired acid value of component (i) of the hybrid polymer Wt.%
DCO fatty acid 10-20
Methyl Methacrylate (MMA) 20-30
2-Ethyl Hexyl Acrylate (2-Eha) 20-10
Methacrylic Acid (MAA) 3-6
Maleic Anhydride 5-2
Ditertiary Amyl Peroxide 1-1.5
O-Xylene 44-29.5
Total 100

Since DCO fatty acid has very high acid equivalent weight so in order to maintain the desired acid value (AV) very high loading of DCOFA is required, and hence as a result the drying of the final paint involving the hybrid polymer dispersion in the absence of modification of fatty acid based acrylic resin by ethylenically unsaturated diacids and/ or anhydride, becomes very slow and final mechanical performance becomes inferior (poor scratch resistance test i.e. 800 gm (less than 1000 gram, Testing done as per ISO 1518-1:2019, Higher the value of gms more is the hardness of films) when the hybrid polymer dispersion is involved in the paint formulation.
Also, on the other hand when acrylic resin is modified only with MA (maleic anhydride), molecular weight and viscosity of the acrylic-alkyd hybrid becomes very high due to higher anhydride/acid ratio in the acrylic component that thus hampers the stability of the dispersion formation causing the hybrid resin to gel.
Stage-3) Synthesis of Alkyd acrylic hybrid dispersion by condensation reaction of Stage-I and Stage-II and further stripping process:
Charge Alkyd resin (80% on solids) 22.5, Acrylic resin (60% on solids) 36.66 in to the reactor and raised the temperature to 140 Deg.C, Apply vacuum and remove complete O-xylene and measure the acid value after every 30 min interval, after reaching acid value below 48 mg/KOH stop heating add Butyl cellosolve 20. Immediately and cool to 70 Deg.C after achieving 70 Deg. C add mixture of Liq. Ammonia 2.40 with DM water 37.60 and disperse this mixture for 1 Hrs.’ at 70 Deg.C. This will be 40 % waterborne alkyd acrylic hybrid dispersion used for paint preparation.
The wt.% of alkyd resin and acrylic resin translates to the wt.% of principal scope by considering dilution of 40 % of the final dispersion and the % solid levels of the alkyd and the acrylic resin involved.
The resulting acid value of the hybrid dispersion is in the levels of 45-51 mg-KOH/ gm within the range of 45-70 mg-KOH/g as desired based on which the dispersion remains stable for even after 12 months and upto 1.5 yr.

Table 3:
Acrylic (i): alkyd (ii) ratio of the hybrid

Acrylic resin having acid value 100-130 mg-KOH/g: Alkyd of hydroxyl value 80-130 mg-KOH/g and acid value less than 5 mg-KOH/g
Results Final paint performance
Gloss
(Standard methodology for measurement)- Gloss meter- ASTM D3928 1998
Air drying time in presence of metallic driers/ tack free time
(By visual observation-by physical touch) Anti-corrosive performance-Water, alkali, and disel dip resistance-Standard methodology for measurement-
Water resistance- ASTM D 2247; Alkali Resistance- ASTM-D1308; Disel resistance- ASTM D2792 - 17

60:40 Very poor and unstable dispersion and uneven viscosity (thixotropic nature) Poor water and alkali resistance 1 Hr for surface dry and 24 Hrs for Hard dry Water Resistance- Blister after 150h
Alkali Resistance- Blister and swelling after 120h
45:55 Stable dispersion with excellent flow and levelling of binder, moderate viscosity that is stable for upto 1.5 yrs. Excellent drying time and water and alkali resistance 30 min for surface dry and 8 hrs hard dry Water Resistance- No blister even after 250h
Alkali Resistance- No film defect after 200h
Salt Spray- No blister after and no underneath corrosion even after 300h
40: 60 Moderately stable dispersion but very high viscosity Fast drying system with inferior flow and finish and inferior in alkali resistance and salt spray resistance 15 Min for surface dry and 4-6 hrs for hard dry. Alkali Resistance- Blister and swelling after 120h
Salt Spray- blister after 150h and also underneath corrosion

Target viscosity range of the present invention is 200 to 500 KU, above 500 KU gives unstable dispersion that is thixotropic in nature. D562 used for viscosity measurements, viscosity measurements were done at temperatures of 30° C.
The ratio of the Components (i) with component (ii) is also important in order to make a stable dispersion and yet attain drying and mechanical performance with good gloss. Higher the concentration of component (i) and lower the concentration of component (ii) will lead to higher Acid Value (AV) of the final hybrid, which may give a better dispersion, but has negative impact on dispersion property such as higher viscosity, or negative impact on final paint performance like tack free drying time, water sensitivity, salt spray. On the other hand, higher the concentration of component (ii) and lower the concentration of component (i) leads to lower acid value and higher hydroxyl value and it is difficult to achieve a stable dispersion having only more than six-month shelf life.

Table 4: Exemplary Paint Formulation involving present acrylic-alkyd hybrid polymeric resin
Ingredients Wt.%
acrylic-alkyd hybrid polymeric resin 57-65
Dispersing agent 0.5-1.5
Pigments –Titanium dioxide 6-10
Extender-(clay etc.) 2-6
defoamer 0.1-0.3
Metal drier 0.5-1.5
Thickener 0.2-1
water 20.2-28.2
Total 100

The present invention could thus provide for oxidative cure aqueous hybrid polymer dispersion suitable for oxidative/auto oxidative cross-linked thermoset that is stable for 6 months to 1 year or more upto 1.5 yrs without the involvement of any surfactants thus enabling a coating/ paint composition with highly improved mechanical, chemical and salt spray performance as compared to thermoplastic binder with difficult to achieve film hardness, impact, salt spray and chemical resistance performance.
The hurdle in the art could be thus overcome, whereby it was previously known that acrylic polymer that is usually built through free radical polymerization of acrylic monomers with unsaturated alkyd polymers results in slow drying time, higher tack free time and low gloss due to less availability of the unsaturated double bond during oxidative curing.
Advantageously, said oxidative cure aqueous hybrid polymer dispersion having low VOC content of less than 20 % and narrow broader particle size distribution (unimodal) of 70-250 nm favoring high gloss on phosphate treated mild steel substrate when applied by spray and after completing 7 days of oxidative curing,
is suitable for pigmented coating/ paint composition for application on metals resulting in excellent air-drying performance in presence of metallic drier, in excellent finish appearance of gloss level @60 Deg is 80-80 units on mild steel substrate and after completing 7 days of oxidative curing, and excellent anti corrosive performance (salt spray resistance more than 500 Hrs) without addition of any anti-corrosive agents; and
also suitable for pigmented coats for direct to metal application resulting in excellent durability (80% gloss retention after 300 Hrs of exposure in QUV A), excellent Diesel dip resistance (No defects in paints film of the MS panel after exposure to dip test of Diesel solution for 24Hrs).