Fl ELD OF I NVENTION

The present invention provides for the synthesis of aqueous dispersions of hydroxy functional acrylic copolymers wherein unsaturated aliphatic acid anhydride modified castor oil has been employed as hydroxyl bearing monomer. Such modified castor oil sourced hydroxyl functionality provides economical and sustainable alternative to petroleum based hydroxyl functional acrylic monomers. Here such modified castor oil derived hydroxyl functionality can be incorporated into the acrylic copolymer either solely or partially with or without petroleum based hydroxy functional acrylic monomers such as hydroxyl ethyl acrylate, hydroxyl ethyl methacrylate and the like.

More particularly, this provides a process comprising the steps involving (a) an ethylenically unsaturated macromonomer obtained from a reaction between castor oil and unsaturated carboxylic acid/anhydride, which is further reacted with (b) acrylic, vinyl or styrenic monomers or a combination thereof through free radical polymerisation that may or may not contain hydroxyl groups and such that at least one of the monomers contain carboxylic moiety or other acidic groups such as sulphates, phosphates and the like and is followed by (c) neutralisation with a neutralising agent and dispersed in to water such that the water is the continuous phase and wherein the volatile organic compound content is less than 10 parts by weight of the dispersion. More advantageously, the aforesaid dispersion is able to provide clear tough glossy highly weather resistant films when cured with suitable polyisocyanate in desired cure ratio and can be used over multiple surfaces such as metal, plastic, wood and masonry etc.

BACKGROUND ART

Waterborne hydroxyl functional acryliccopolymerdispersions that crosslink with suitable polyisocyanate to form polyurethanes are steadily gaining ground to replace solvent borne polyurethane systems in high performance coating applications. The preferred method of making these dispersions is to synthesise the polymers in solvent phase followed by neutralisation of the acidic groups. The solvents need to be distilled at a stage to reduce the Volatile Organic Compound (VOC) content. In order to avoid distillation of the solvent, reactive diluents containing hydroxyl groups are used while processing.

Castor oil and its derivatives have been used in water borne acrylic dispersion as given in patent application WO2012131050 A1 which describes the method of synthesising acrylics in these derivatives as reactive diluents that also impart hydroxyl functionality.

Patent EP1699835 B1 discloses a method of processing acrylic dispersions in the presence of lactone containing compounds and low molecular weight polyols as diluents.

EP2342 242 B1 teaches a method to synthesize the hydroxyl containing dispersions in the presence of a fatty acid containing atleast one ethylenic double bond and a hydroxyl group.

The use of these polyols have been essentially to lower the solvent content in waterborne resins while they also react with the crosslinker at cure stage. However, since these are not grafted into the acrylic polymer, they do not impart superior performance characteristics to the acrylic copolymer when cured with suitable cross linkers.

Patent application WO2014188438 A1 teaches acrylic polyols having carboxylic acid anhydride modified castor oil as hydroxy functional monomer in its backbone and a method to modify the acrylic backbone using castor oil functionalities that is a solvent based resin with improved renewable content in polymers.

It is thus apparent that there is still scope to improve the renewable content of the resin by grafting the renewable content onto the copolymer backbone enabling water borne dispersion with superior performance properties and economic efficiency. It is also imperative to make it environmentally friendly by lowering the volatile organic compound (VOC) content. It is also a need in the art to have a macromonomer that would be a suitable substitute for low Tg monomers and carboxylic acid containing unsaturated monomers for reacting with the acrylic backbone.

OBJECTS OF THE I NVENTI ON

The primary object of the present invention is to provide for waterborne hydroxy functional acrylic copolymer/resin dispersion with grafted renewable content in the polymer backbone and a process of synthesis thereof.

It is another object of the present invention to provide for a macromonomer as a reactant with renewable content for polymerization leading to the copolymer that would favour grafting of the renewable content onto the copolymer backbone to enable water borne dispersion with improved properties and economic efficiency.

It is yet another object of the present invention to partially or completely derive the hydroxyl functionality of the dispersion from the grafted macromonomer.

It is another object of the present invention to partially or completely substitute the low Tg< 10 °C monomers such as butyl acrylate, ethyl hexyl acrylate and other similar acrylates with the grafted co-monomer in the acrylic backbone. It is yet another object of the present invention to partially or completely source the carboxylic functionality for neutralisation of the dispersion from the grafted macromonomer.

Yet another object of the present invention is to provide for said water borne dispersion with volatile organic compound content less than 10 parts by weight of the dispersion.

Another object of the present invention is to provide for said macromonomer as a reactant that would favour inclusion of other specialty moiety such as acrylic/vinyl silanes, acrylic epoxy, acrylic fluoro monomers and others in the acrylic backbone for further enhancement of performance. It is yet another object of the present invention to provide for said aqueous dispersion that may be crosslinked through reaction with polyisocyanates at ambient temperature for 2 pack polyurethane system or crosslinked with melamine formaldehyde / urea formaldehyde resin at elevated temperature in 1 pack systems leading to tough, glossy and durable coatings having low VOC.

It is another object of the present invention to provide for said waterborne polyol dispersion that would react with polyisocyanates preferably in the OH: NCO equivalent ratios in the desired range of 1 :0.7 to 1 : 1.8 as desired that would favour tough weather resistant polyurethane films.

It is yet another objective of the present invention to provide for a coating/ paint composition which when coated on a surface would have gloss retention of more than 95% over 1000 hrs of QUV (313 nm) exposure that is most desired in surface coating applications. SUMMARY OF THE INVENTION

According to the basic aspect of the present invention there is provided a waterborne hydroxy functional acrylic copolymer/resin dispersion comprising a copolymer with a backbone including grafted renewable castor oil sourced content and which comprises copolymerized ethylenically unsaturated castor oil based macromonomer and at least one ethylenically unsaturated monomer.

Preferably said waterborne hydroxy functional acrylic copolymer/resin dispersion comprises an unsaturated aliphatic acid anhydride modified castor oil as hydroxyl bearing monomer copolymerized with acrylic, vinyl or styrenic monomers or a combination thereof.

According to another preferred aspect of the present invention there is provided said water borne hydroxy functional acrylic copolymer/resin dispersion wherein said castor oil based macromonomer comprises a reaction product of castor oil and unsaturated carboxylic acid anhydride providing said copolymer backbone with grafted renewable modified castor oil monomer which is copolymerizable with et hy len ically unsaturated monomers including acrylic, vinyl or styrenic monomers or a combination thereof.

Advantageously, said waterborne hydroxy functional acrylic copolymer/resin dispersion of the present invention comprises of dispersion in water with water as the continuous phase having very low volatile organic content of less than 10 parts by weight of the dispersion.

Preferably, said waterborne hydroxy functional acrylic copolymer dispersion has polymer molecular weight in the range of 1800-25000 and the hydroxyl value in the range of 20-180 mg KOH/gm with a VOC content of < 1 OOg/Kg.

More preferably, in said waterborne hydroxy functional acrylic copolymer/resin dispersion said macromonomer as a reaction product of castor oil and unsaturated carboxylic acid anhydride involves carboxylic acidic group including anyone or more anhydride, acid chloride, carboxylic acid group linked to a vinyl group capable of undergoing free radical polymerisation with at least one ethylenically unsaturated monomers including acrylic, vinyl or styrenic monomers or a combination thereof.

Accordingly, the present invention provides a hydroxyl functional acrylic dispersion involving a copolymer grafted with renewable macromonomer derived from the reaction of castor oil and unsaturated carboxylic acid anhydride. The grafting of said macromonomer onto the copolymer backbone enables to partially or completely substitute the requirements of other hydroxyl containing monomers, soft or low Tg monomers and monomers containing carboxylic acid groups and yet attain Tg <60°C.

It is thus surprisingly found by way of the present invention that when castor oil is reacted with unsaturated carboxylic acid anhydride, an ethylenically unsaturated castor oil based macromonomer results that favours a copolymer with a backbone including grafted renewable castor oil sourced hydroxyl content comprising copolymerized castor oil based macromonomer and acrylic, vinyl or styrenic monomers or a combination thereof. Said copolymer when neutralized by a neutralizing agent favours dispersion in water with water as the continuous phase having very low volatile organic compound content of less than 10 parts by weight of said dispersion. Interestingly, it was observed that addition of castor oil not leading to grafting of the same in the acrylic backbone in the dispersion failed to yield a clear tough weather resistant film upon curing as is seen in Fig 1.

Further, it was noticed that there was a remarkable difference in the glass transition temperature of the copolymer with grafted castor oil based macromonomer in said copolymer backbone which enabled complete substitution of low Tg monomers usually employed in acrylic polymer synthesis as is demonstrated under Examples ll-IX).

Advantageously, the polymeric dispersion of the present invention comprising said macromonomer reactant favoured tough, clear and weather resistant films.

According to another preferred aspect of the present invention there is provided said waterborne hydroxy functional acrylic copolymer/resin dispersion wherein said ethylenically unsaturated monomers adapted for free radical polymerisation includes monomers with or without hydroxyl groups wherein at least one monomer involves acidic groups including carboxylic acid, sulphates, sulphonates, phosphates that include, acrylic acid, alkyl acrylic/ methacrylic acids, maleic anhydride, Itaconic anhydride, acryloylchloride, acryloylsufates, vinylsulphates, vinyl sulphonates, vinyl phosphates, vinyl or acryloyl derivatives of phosphates.

Preferably in said waterborne hydroxy functional acrylic copolymer/resin dispersion said ethylenically unsaturated monomers includes acrylates, methacrylates, modified acrylates/methacrylates, aryl acrylates, alkyl acrylates, styrene and its derivatives, vinyl monomers, preferably includes monomers of vinyl silane, vinyl fluoride, vinyl chlorides, cross-linking monomers. These monomers are present in the range of 15-90% of the total copolymer/ resin, preferably in the range of 25-90% and more preferably in the range of 35-90% Advantageously, said waterborne hydroxy functional acrylic copolymer/resin dispersion has glass transition temperature (Tg) less than 60°C and is free of any elasticity providing (low Tg< 10°C ) monomers.

More advantageously, said waterborne hydroxy functional acrylic copolymer/resin dispersion is provided wherein said hydroxy and carboxylic functionality is partially or completely sourced from unsaturated aliphatic acid anhydride modified castor oil based macromonomer.

Advantageously, said waterborne hydroxy functional acrylic copolymer/resin dispersion is provided wherein the renewable content of the copolymer/resin ranges from 5-65% preferably in the range of 5-55%, most preferably in the range of 10-40%.

According to another preferred aspect of the present invention there is provided said waterborne hydroxy functional acrylic copolymer/resin dispersion wherein said copolymer backbone having grafted macromonomer favours partial or complete substitution of soft or low Tg< 10 °C monomers such as butyl acrylate, 2-ethyl hexyl acrylate and the like.

Advantageously, said waterborne hydroxy functional acrylic copolymer/resin dispersion is provided wherein said copolymer backbone with modified castor oil grafted renewable content is capable of curing with polyisocyanates at desired ratio range of 1:0.7 to 1 : 1.8 favouring clear, tough, glossy and durable films/ coating including pigmented topcoats, adhesives and sealants.

According to another aspect of the present invention there is provided a process for manufacturing waterborne hydroxyl functional acrylic copolymer/resin dispersion comprising steps involving copolymerization of renewable castor oil based macromonomer with acrylic, vinyl or styrenic monomers or a combination thereof. Preferably said process for the manufacturing of said waterborne hydroxy functional acrylic copolymer/resin dispersion is provided comprising the steps of (a) reacting castor oil with unsaturated carboxylic acid anhydride providing for the macromonomer;

(b) copolymerizing said macromonomer with ethylenically unsaturated monomers in the presence of a free radical initiator;

(c) neutralizing the copolymer with ammonia or an organic amine followed by dispersing the polymer in water to obtain therefrom said waterborne hydroxy functional acrylic copolymer/resin dispersion. Preferably in said process is performed at a temperature range of 80-180°C more preferably in the range of 100-160°C

Preferably in the said process the free radical initiator is selected from the group of butyl peroxides, per benzoates, amyl peroxides, peroxylalkyl carbonates, azo nitriles and the like. These are typically used in the range of 0.5-10% of the total copolymer/ resin, preferably in the range of 1-8% more preferably in the range of 1.5-7% of the total copolymer /resin.

Preferably in said process, neutralizing the copolymer involves neutralizing agents such as ammonia, N, N-dimethylethanolamine, N,N- dimethylisopropanolamine, N-methylmorpholine, triethylamine, ethyldiisopropylam ine, N-methyldiethanolam ine, diet hy let hanolamine, triethanolamine, butanolamine, morpholine, 2-am inomethyl-2-methylpropanol and isophoronediamine etc.

According to another aspect of the present invention there is provided a polyurethane composition comprising

(a) waterborne hydroxy functional acrylic copolymer/resin dispersion comprising a copolymer with a backbone including grafted renewable castor oil sourced content and which comprises copolymerized ethylenically unsaturated castor oil based macromonomer and at least one ethylenically unsaturated monomer

(b) a polyisocyanate in the form of isocyanate-terminated prepolymer or blocked isocyanates.

Preferably said waterborne hydroxy functional acrylic copolymer/resin dispersion comprises a copolymer backbone grafted with renewable castor oil derived macromonomer wherein said copolymer comprises castor oil based macromonomer and ethylenically unsaturated monomers including acrylic, vinyl or styrenic monomers or a combination thereof.

Preferably said polyisocyanates are selected from toluene diisocyanate, methylene diphenyliisocyanate, polymeric methylene diphenyldiisocyanate, carbodiimide-modified methylene diphenyldiisocyanate, hydrogenated methylene diphenyldiisocyanate, isophoronediisocyanate, biurates & isocyanurate of hexamethylene di-isocyanate and isophorone-di-isocyanate. Preferred polyisocyanate derivatives are hydrophilic modified polyisocyanates such as those available under the Easaqua (M/s. Vencorex Chemicals) and Bayhydur (M/s Covestro) series.

Preferably in said polyurethane composition said acid anhydride modified castor oil based macromonomer comprise a reaction product of castor oil and unsaturated carboxylic acid anhydride providing said copolymer backbone with grafted renewable castor oil sourced hydroxyl content which is copolymerizable with ethylenically unsaturated monomers like acrylic, vinyl or styrenics or a combination thereof. More preferably said polyurethane composition is provided as tough weather resistant polyurethane film comprising waterborne hydroxy functional acrylic copolymer/resin dispersion and polyisocyanates in the OH: NCO equivalent ratios in the desired range of 1 :0.7 to 1 : 1.8 for the end application.

According to another preferred aspect of the present invention there is provided a process for manufacturing of said polyurethane composition comprising the steps of (a) providing copolymer backbone with grafted renewable content as waterborne hydroxy functional acrylic copolymer/resin dispersion involving a copolymer of renewable ethylenically unsaturated castor oil based macromonomer and at least one ethylenically unsaturated monomer; and (b) a polyisocyanate for reaction to obtain thereform said polyurethane composition.

According to another aspect of the present invention there is provided an ethylenically unsaturated castor oil based macromonomer comprising an ethylenically unsaturated macromonomer which is a reaction product of castor oil and unsaturated carboxylic acid/anhydride including hydroxy functional monomer.

Accordingly, poiyisocyanates include neat polyisocyanate, isocyanate- terminated prepo!ymer or blocked isocyanates and are selected from toluene diisocyanate, methylene dipheny!iisocyanate, polymeric methylene diphenyldiisocyanate, carbodiimide-modified methylene diphenyldiisocyanate, hydrogenated methylene diphenyldiisocyanate, isophoronediisocyanate, biurates&isocyanurate of hexamethylene di-isocyanate and isophorone-di- isocyanate. Preferred polyisocyanate derivatives are hydrophilic modified poiyisocyanates such as those available under the Easaqua(M/s. Vencorex Chemicals) and Bayhydur (M/s Covestro) series. it was found that the castor oil macromonomer grafted hydroxyl functional acrylic copolymer/ resin and dispersions thereof could be cured at a ratio in the range of 1:0.7 to 1:1.8 which is most desirable to provide for a tough, glossy weather resistant polyurethane film which polyurethanes finds end use and application including clear or pigmented topcoats, adhesives and sealants.

Surprisingly it was also found that the castor oil macromonomer grafted hydroxyl functional acrylic copolymer/ resin and dispersions thereof when cured with the polyisocyanate gave good mechanical properties, superior gloss retention and excellent weathering resistance as tested by gloss retention of more than 95% under 1000 hrs of QUV-B exposure as compared to the 65-75% gloss retention after same duration of solvent borne acrylic copolymers as given in the prior art. The present invention is explained hereunder in greater details in relation to the non-limiting exemplary illustrations and Figures.

BRI EF DESCRI PTI ON OF Fl GURES

Figure 1 : illustrative films showing the clarity difference between (a) non grafted castor oil acrylic polyol dispersion (Example 1); and (b) grafted castor oil acrylic polyol dispersion (Example VI);

Figure 2: illustrating Dynamic Mechanical Analysis (DMA) of Polyurethane films (cured with NCO in the ratio 1:1.1) showing the difference on thermal and mechanical behaviour between (a) non grafted castor oil acrylic polyol dispersion (Example I); and (b) grafted castor oil acrylic polyol dispersion (Example III)

DETAI LED DESCRI PTI ON OF THE I NVENTI ON

As discussed herein before there is provided waterborne hydroxy functional acrylic copolymer/resin dispersion comprising a copolymerwith a backbone including grafted renewable castor oil sourced content, which copolymer comprises copolymerized ethylenically unsaturated castor oil based macromonomer and at least one ethylenically unsaturated monomer. Said macromonomer is obtained of a reaction between castor oil and unsaturated carboxylic acid or anhydride, used as hydroxy functional monomer.

Waterborne hydroxy functional polymeric dispersion of the present invention comprises (a) an ethylenically unsaturated macromonomer obtained of a reaction between castor oil and unsaturated carboxylic acid/anhydride reacted, which macromonomer is further reacted with (b) other ethylenically unsaturated monomers through free radical polymerisation that may or may not contain hydroxyl groups and such that at least one of the monomers contain carboxylic moiety or other acidic groups such as sulphates, phosphates and the like and is followed by (c) neutralisation with a neutralising agent and dispersed in to water such that the water is the continuous phase and wherein the volatile organic compound content is less than 10 parts by weight of the dispersion. Preparation of waterborne hydroxyl functional acrylic copolymer dispersion of the present invention thus comprises the steps of

a. An ethylenically unsaturated macromonomer that is made through a reaction between castor oil and unsaturated carboxylic acid or anhydride at a temperature range of 80-180°C and is used as a hydroxyl functional monomer;

b. Other ethylenically unsaturated monomers reacted through free radical polymerisation in the temperature range of 80-180°C that may or may not contain hydroxyl functionality;

c. Further reacted in the temperature range of 80-180°C with monomers that contain carboxylic acid moiety or other acidic groups such as sulphates, phosphates and the like;

d. followed by neutralisation with a neutralising agent in the temperature range of 50-120°C and dispersed in to water in the temperature range of 30-90°C such that the water is the continuous phase;

e. the resultant acrylic copolymer dispersion provides hydroxyl value in the range of 20-180 mg KOH /gm.

In an embodiment of the present invention, the ethylenically unsaturated macromonomer has been synthesised through a reaction between castor oil and aliphatic unsaturated carboxylic acidic groups. The acidic group may be in the form of anhydride, acid chloride, carboxylic acid that is attached to anorganic backbone that contains a vinyl group which is capable of undergoing free radical polymerisation. The renewable content in the final polymer may range from 5 - 65% preferably in the range of 5-55%, most preferably in the range of 10-40%. The hydroxyl groups of the dispersion may be partially or solely sourced from the renewable content.

The ethylenically unsaturated monomers may belong to the class of acrylates, methacrylates, modified acrylates/methacrylates.styrene and its derivatives or vinyl monomers. The monomers that provide elasticity such as butyl acrylate, ethylhexyl acrylate may be avoided as the macromonomer provides the requisite flexibility. Preferable monomers may also include vinyl silane, vinyl fluoride, vinyl chlorides, cross-linking monomers. These monomers are present in the range of 15-90% of the total copolymer/ resin, preferably in the range of 25-90% and more preferably in the range of 35-90%. It is imperative that one of the monomers belong to the class of acrylic/ methacrylic acids, vinyl sufonates, acryloylsufates, vinyl or acryloyl derivatives of phosphates. The amount of such monomers should not exceed 10% of the total ethylenically unsaturated monomer mixture.

The solvent used for the solution polymerisation typically belongs to the class of solvents that have boiling points higher than 150°C and should not contain groups that interfere with the free radical reaction. The amount of solvent should be in the range of 0.5-15% preferably in the range of 1-12% and most preferably in the range of 1-10% of the total reaction mixture.

The polymer thus prepared through solution polymerisation is treated with a neutralising agent of the type include N, N-dimethylethanolamine, N,N- dimethy!isopropano!amine, N-methy!morpholine, triethy!amine, ethyldiisopropylam ine, N-methyldiethanoiam ine, diethy!ethanolamine, triethanoiamine, butanolamine, morpholine, 2-aminomethy!-2-methy!propanol and isophoronediamine. The neutralised polymer is further dispersed in deionised water to give a milky white dispersion. Accordingly, the polymeric backbone would be made up of the grafted macromonomer reacted with ethylenically unsaturated monomers through free radical polymerisation such that the polymer has a molecular weight is in the range of 1800-25000 and the hydroxyl value in the range of 20-180 mg KOH with a VOC content of < 1 OOg/Kg. Example I : Acrylic polyol dispersion with non-grafted castor oil

To 250g of castor oil taken with 60g Dipropylene glycol methyl ether and heated to 140°C. To this added a mixture of 100g styrene, 80 g methyl methacrylate, 150g butyl methacrylate, 15g methacrylic acid with 25 g ditertiary butyl peroxide within a span of 4 hrs at 140°C. Further 1.0 g of ditertiary butyl peroxide with 10 g of Dipropylene glycol methyl ether was metered in for 5 mins and allowed to remain at 140°C for 60 mins. The resulting polymer was neutralised with 15g N, N-dimethylethanolamine at 100°C. To the neutralised polymer added 700 g deionised water at 80°C and stirred for 30 mins. The resulting acrylic polyol dispersion was found to have solid content of 48.5%, pH 7.9, Hydroxyl value (mg KOH/gm)96, renewable content on polymer solids 39.8%, VOC content : 60g/Kg. Mn: 940, 3100 , Tg : 13°C. Dispersion was applied at dry film thickness of 45-55 micron and allowed to dry at ambient temperature (25-30°C) for 48 hrs. Film appearance: hazy, Water resistance: Poor (whitening of the film occurs within 1 hr).

Example II : Modified Acrylic polyol dispersion with all hydroxyl functionality sourced from maleinized castor oil To 250g of castor oil taken with 60g Dipropylene glycol methyl ether added 1 Og maleic anhydride and reacted at 140° C for 2 hrs. To this added a m ixture of 10Og styrene, 80 g methyl methacrylate, 150g butyl methacrylate, 15g methacrylic acid with 25 g di-tertiarybutyl peroxide within a span of 4 hrs at 140°C. Further 1.0 g of ditertiary butyl peroxide with 10 g of Dipropylene glycol methyl ether was metered in for 5 mins and allowed to remain at 140°C for 60 mins. The resulting polymer was neutralised with 15g N,N- dimethylethanolamine at 100°C. To the neutralised polymer added 700 g deionised water at 80°C and stirred for 30 mins. The resulting acrylic polyol dispersion was found to have solid content of 47.5%, pH 7.9, Hydroxyl value (mg KOH/gm)96, renewable content on polymer solids 39.8%, Tg: -20°C. Mol.wt (Mn): 2300; VOC content:60g/Kg.

Dispersion was applied at dry film thickness of 45-55 micron and allowed to dry at ambient temperature (25-30°C) for 48 hrs. Film appearance: clear, Water resistance: good (no whitening of the film after 6 hrs) Example III : Modified Acrylic polyol dispersion with all hydroxyl functionality sourced from maleinized castor oil.

To 150g of castor oil taken in 40g Dipropylene glycol methyl ether added 5g Maleic anhydride and reacted at 140°C for 2 hrs. To this added a mixture of 60 g styrene, 200 g butyl methacrylate, 80 g methyl methacrylate, 15 g methacrylic acid , 20 g dipropylene glycol methyl ether with 26 g ditertiary butyl peroxide within a span of 4 hrs. Further 1.0 g of ditertiary butyl peroxide with 10 g of Dipropylene glycol methyl ether was metered in for 5 mins and allowed to remain at 140°C for 60 mins. The resulting polymer was neutralised with 15g Ν,Ν-dimethylethanolamine at 100°C. To the neutralised polymer added 600 g deionised water at 80°C and stirred for 30 mins. The resulting acrylic polyol dispersion was found to have solid content of 50.5%, pH 7.9, Hydroxyl value(mg KOH/gm)54, renewable content on polymer solids 24.5%, Tg -11°C, Mn 2500, VOC content :70g/Kg .

Dispersion was applied at dry film thickness of 45-55 micron and allowed to dry at ambient temperature (25-30°C) for 48 hrs. Film appearance: clear, Water resistance: good (no whitening of the film after 6 hrs) Example IV: Modified Acrylic polyol dispersion with all hydroxyl functionality sourced from maleinized castor oil

To 80 g of castor oil taken in 40g Dipropylene glycol methyl ether added 3.0g Maleic anhydride and reacted at 140°C for 2 hrs. To this added a mixture of 80 g styrene, 200 g butyl methacrylate, 80 g methyl methacrylate, 20 g methacrylic acid, 20 g dipropylene glycol methyl ether with 20 g ditertiary butyl peroxide within a span of 4 hrs. Further 1.0g of ditertiary butyl peroxide with 10 g of Dipropylene glycol methyl ether was metered in for 5 mins and allowed to remain at 140°C for 60 mins. The resulting polymer was neutralised with 15g N-methylmorpholine at 100°C. To the neutralised polymer added 425g deionised water at 80°C and stirred for 30 mins. The resulting acrylic polyol dispersion was found to have solid content of 49% pH 7.9, Hydroxyl value (mg KOH/gm)29, renewable content on polymer solids 16%, Molwt (Mn) 9300, Tg : -5°C; VOCcontent :70g/Kg.

Dispersion was applied at dry film thickness of 45-55 micron and allowed to dry at ambient temperature (25-30°C) for 48 hrs. Film appearance: clear, Water resistance: good (no whitening of the film after 6 hrs)

Example V: Modified Acrylic polyol dispersion with hydroxyl functionality sourced from maleinized castor oil/hydroxyl monomer

To 80 g of castor oil taken in 40g Dipropylene glycol methyl ether added 3.0g Maleic anhydride and reacted at 140°C for 2 hrs. To this added a mixture of 80 g styrene, 200 g butyl methacrylate, 80 g methyl methacrylate, 10 g hydroxyl ethyl methacrylate, 20 g methacrylic acid, 20 g dipropylene glycol methyl ether with 40 g ditertiary butyl peroxide within a span of 4 hrs. Further 1.Og of ditertiary butyl peroxide with 10 g of Dipropylene glycol methyl ether was metered in for 5 mins and allowed to remain at 140°C for 60 mins. The resulting polymer was neutralised with 15g N,N- dimethylethanolamine at 100°C. To the neutralised polymer added 392.5g deionised water at 80°C and stirred for 30 mins. The resulting acrylic polyol dispersion was found to have solid content of 48%, pH7.6, Hydroxyl value (mg KOH/gm) 34, renewable content on polymer solids 16% Tg: 4°C, Molwt (Mn) 2850,VOCcontent :70g/Kg. Dispersion was applied at dry film thickness of 45-55 micron and allowed to dry at ambient temperature ( 25-30°C) for 48 hrs. Film appearance: clear, Water resistance: good (no whitening of the film after 6 hrs)

Example VI : Modified Acrylic polyol dispersion with hydroxyl functionality sourced from maleinized castor oil/hydroxy monomer To 50 g of castor oil taken in 40g Dipropylene glycol methyl ether added 2.5g Maleic anhydride and reacted at 140°C for 2 hrs. To this added a mixture of 85 g styrene, 200 g butyl methacrylate, 90 g methyl methacrylate, 32 g hydroxyl ethyl methacrylate, 20 g methacrylic acid, 10 g dipropylene glycol methyl ether with 30 g ditertiary butyl peroxide within a span of 4 hrs. Further 1.0g of ditertiary butyl peroxide with 10 g of Dipropylene glycol methyl ether was metered in for 5 mins and allowed to remain at 140°C for 60 mins. The resulting polymer was neutralised with 15g N, N- dimethylethanolamine at 100°C. To the neutralised polymer added 419.5g deionised water at 80°C and stirred for 30 mins. The resulting acrylic polyol dispersion was found to have solid content of 47%, pH 7.6, Hydroxyl value (mg KOH/gm)48, renewable content on polymer solids 10.6% ,Mol.wt (Mn): 3560 ; Tg: 15.5°C ;VOCcontent :50 g/Kg.

Dispersion was applied at dry film thickness of 45-55 micron and allowed to dry at ambient temperature ( 25-30°C) for 48 hrs. Film appearance : clear, Water resistance: good (no whitening of the film after 6 hrs)

Example VII : Modified Acrylic polyol dispersion with hydroxyl functionality sourced from maleinized castor oil/hydroxyl monomer To 150 g of castor oil taken in 40g Dipropylene glycol methyl ether added 5.0g Maleic anhydride and reacted at 140° C for 2 hrs. To this added a m ixture of 60 g styrene, 100 g butyl methacrylate, 60 g methyl methacrylate, 20 g hydroxyl ethyl methacrylate, 20 g methacrylic acid, 10 g dipropylene glycol methyl ether with 25 g ditertiary butyl peroxide within a span of 4 hrs. Further 1.0g of ditertiary butyl peroxide with 10 g of Dipropylene glycol methyl ether was metered in for 5 mins and allowed to remain at 140°C for 60 mins. The resulting polymer was neutralised with 15g N,N- dimethylethanolamine at 100°C. To the neutralised polymer added 390g deionised water at 80°C and stirred for 30 mins. The resulting acrylic polyol dispersion was found to have solid content of 46.5%, pH 7.6, Hydroxyl value (mg KOH/gm)75, renewable content on polymer solids 30.6% , Mol.wt (Mn); 6300; Tg: 11.2 °C .VOCcontent :70g/Kg.

Dispersion was applied at dry film thickness of 45-55 micron and allowed to dry at ambient temperature (25-30°C) for 48 hrs. Film appearance : clear, Water resistance: good (no whitening of the film after 6 hrs)

Example VIII : Modified Acrylic polyol dispersion with some hydroxyl functionality sourced from maleinized castor oil and cross-linked with polyisocyanate To 80 g of castor oil taken in 30g Dipropylene glycol methyl ether added 5.0g Maleic anhydride and reacted at 140°C for 2 hrs. To this added a mixture of 80 g styrene, 200 g butyl methacrylate, 60 g methyl methacrylate, 25 g hydroxyl ethyl methacrylate, 30 g methacrylic acid, 10 g dipropylene glycol methyl ether with 30 g ditertiary butyl peroxide within a span of 4 hrs. Further 1.0g of ditertiary butyl peroxide with 10 g of Dipropylene glycol methyl ether was metered in for 5 mins and allowed to remain at 140°C for 60 mins. The polymer mixture was cooled to 80°C and 40g of isophoronediisocyanate was added over a period of 20 mins followed by stirring for 60 mins. The resulting polymer was neutralised with 15g N,N- dimethylethanolamine at 80°C. To the neutralised polymer added 450g deionised water at 70°C and stirred for 30 mins. The resulting acrylic polyol dispersion was found to have solid content of 40%, pH 7.8, Hydroxyl value (mg KOH/gm)20, renewable content on polymer solids 30.6%, Tg:29°C, Molwt (Mn): 2100, VOC content :70g/kg.

Dispersion was applied at dry film thickness of 45-55 micron and allowed to dry at ambient temperature (25-30°C) for 48 hrs. Film appearance: clear, Water resistance: good (no whitening of the film after 4 hrs)

Example IX: Modified Acrylic polyol dispersion with high hydroxyl functionality sourced from maleinized castor oil and Hydroxyl monomer.

To 120 g of castor oil taken in 35 g of Dipropylene glycol methyl ether added 21 g of Maleic anhydride and reacted at 140°C for 2 hrs. To this added a mixture of 60 g styrene, 70 g butyl methacrylate, 60 g methyl methacrylate, 70 g hydroxyl ethyl methacrylate, 14 g methacrylic acid, 10 g dipropylene glycol methyl ether with 20 g ditertiary butyl peroxide within a span of 4 hrs. Further 1.0g of ditertiary butyl peroxide with 10 g of Dipropylene glycol methyl ether was metered in for 5 mins and allowed to remain at 140°C for 60 mins. The polymer mixture was cooled to and was neutralised with 15g N, N-dimethylethanolamine at 80°C. To the neutralised polymer added 275g deionised water at 70°C and stirred for 30 mins. The resulting acrylic polyol dispersion was found to have solid content of 50.3%, pH 7.8, Hydroxyl value (mg KOH/gm) 148, renewable content on polymer solids 34% , Tg:-5°C , Molwt (Mn): 2200, VOC content : 70g/kg.

Dispersion was applied at dry film thickness of 45-55 micron and allowed to dry at ambient temperature (25-30°C) for 48 hrs. Film appearance: clear, Water resistance: good (no whitening of the film after 6 hrs)

The acrylic polyol dispersions as in examples ll-IX were cured with Easaqua 803 XD with a cure ratio of OH: NCO: : 1:1 on steel panels. Coating dry film thickness was maintained at 40-60 microns. After 7 days curing at ambient temperature (25-30°C), all panels passed 50 xylene rubs and provided scratch hardness in the range of 1.00-2.5 kg depending on hydroxyl functionality. Exam pie X: Paint com position

A glossy paint composition made with dispersion as given in Example VI.

The paint was spray applied over burnished mild steel panels to build a dry film thickness of 50-60μ. The following were the properties obtained after 7 days of ambient cure at 25-30°C.GIoss @ 60° head: 90 Mechanical properties: 75 Solvent rubs with Xylene and Methyl ethyl ketone without failure. Scratch hardness: 1.7 Kg; Flexibility on conical mandrel (tin panels): Passes 1/8"

Chemical resistance: No blistering, No Chalking, No gloss reduction after immersion in 10% sulphuric acid, 10% sodium hydroxide and mineral turpentine oil for 7 days.

Weathering resistance: Gloss retention in panels after exposure to 1000 hrs of QUV B exposure (ASTM 53-Fluorescent UV-condensation type exposure)> 95% Corrosion resistance (ASTM B117 Salt Spray Test): 250 hrs of salt spray when applied directly to metal and more than 1000 hrs when applied on commercial epoxy primers.

It can be thus clearly concluded from the above exemplary illustrations that the acrylic polyol dispersions prepared with non-grafted castor oil when coated as a film lack in clarity and is hazy as revealed in Fig. 1. Water resistance is poor leading to whitening of the film as compared to the dispersion with grafted castor oil as a film that remains clear and is free of any whitening effect. Further such dispersions of the present invention when cured with polyisocyanates in the desired ratios provide tough and weather resistant films with superior clarity.

Also low Tg monomers such as butyl acrylate, ethyl hexyl acrylate can be completely substituted to provide for the desired flexibility of the dispersions and films according to the present invention of Tg <60°C that also corresponds to the Tg & DMA results provided under Fig.2.

It is thus possible by way of the present advancement to provide for a waterborne polymeric binder having renewable content that is made through a reaction between castor oil and unsaturated carboxylic acid or anhydride and grafted onto the polymeric backbone. Advantageously, said renewable macromonomer while is able to completely or partially substitute the hydroxyl and carboxylic groups, is also able to completely provide the flexibility in the polymeric backbone in the complete absence of elasticity imparting monomers of butyl acrylate, ethyl hexyl acrylate and the like, wherein the copolymer thus formed is further neutralizable with a neutralising agentand gets dispersed in water such that the water is the continuous phase and the volatile organic compound(VOC) is less than ten parts by weight of the dispersion. More advantageously, the aforesaid dispersion is able to provide clear tough glossy and weather resistant films when cured with polyisocyanates in desired cure ratios and can be used over multiple surfaces such as metal, plastic, wood and masonry.