FI ELD OF I NVENTI ON

The present invention relates to cost effective binder and coating formulations thereof comprising maleated rosin modified polyester resin form ulations applicable as a single pack system not only meeting but even exceeding properties of high cost resins such as shellac with regards to gloss, grain filling and water resistance.

BACKGROUND ART Conventionally natural polymers such as Shellac, Rosin and Chandruce resins are commonly used to prepare single pack wood polish. They have issues such as high cost, poor water resistance, presence of natural impurities, inconsistent lot to lot properties, haze in com mon solvents (alcohols) due to presence of natural waxes and a settling tendency due to the presence of impurities. Synthetic polymers such as ketonic resins (cyclohexanone formaldehyde) are often blended to reduce cost but suffer from poor water resistance and presence of formaldehyde which is a CMR (carcinogenic, mutagenic, or toxic for reproduction).

On this prior known rosin material is referred as below: CN 102010503A teaching a method that comprises ( 1 ) allowing addn. reaction of rosin and maleic anhydride (at a molar ratio of 1 : 0.4- 1 ) at 200-220° C for 1 -2 h, and (2) adding pentaerythritol and catalyst ZnO into the reaction system, dissolving at 220-230°C and heating at 250-265°C, allowing esterification of the addn. product for 5.5-6.5 h, sampling and continuing the reaction till acid value 150-170 mg-KOH/g, softening point 140-155°C, and color no. < 10. The product is suitable for use in waterborne inks, and the resulting film from the inks is tough and has good after-tacking, water and alkali resistance. Preparation of rosin acid- modified terephthalic acid-type unsaturated polyester By Qi, Shuang-chun; Xing, Guang-en Zhongguo Suliao (2005), 19(9), 61 -63, teaches synthetic method of rosin acid-modified terephthalic unsaturated polyester resin was studied. The optimal reaction temp was 230-240°. Terephthalic acid was reacted with glycols. When the acid value reduced to 19 ± 2 mg KOH/g, maleic anhydride was introduced and rosin acid was added as the acid value reduced to 60 ± 2 mg KOH/g. The terminating hydroxy groups were allowed to esterify at 190-200°. The soly. and reactivity of terephthalic unsatd. polyester resin were improved by rosin acid. Its reactivity with styrene was higher than dicyclopentadiene modified counterpart, the mechanical properties properties, thermal and chemical resistances were better than unmodified ones. In this reference, unsaturated polyester is being prepared using the unsaturation of maleic anhydride which is later crosslinked with styrene/DCPD but the maleic anhydride unsaturation is not consumed during the Diels Alder reaction with Rosin.

Synthesis and property study of rosin modified terephthalic unsaturated polyester By Tang, Jun; Xu, Guo-cai; Shen, Na Reguxing Shuzhi (2009), 24(4), 18-20, provides rosin terminated terephthalic unsatd. polyester resin (TUPR) was synthesized. The effect of different catalysts on the conversion rate of the reaction was investigated. The optimum compound and amount of catalyst were determined. The mech. properties, thermal property and corrosion resistance of castings of the TUPR before and after modification and general orthophthalic unsaturated polyester were compared. The results showed that the catalytic effect was best with the mass ratio of monobutyl tin oxide to stannous octoate 1 : 1 and amount 0.5% (based on the wt. of terephthalic acid). The mechanical property, corrosion resistance and water resistance of rosin modified TUPR were better than the orthophthalic resin, and the water resistance, alkali resistance and the compatibility with styrene of it were better than the unmodified TUPR. In this prior art unsaturated polyester where the maleic anhydride unsaturation is left unreacted in the polyester for further reaction with styrene. SU 1235891 A1 19860607 1986 Self-polishing em ulsion for floors from U.S.S. R. By Gorin, G. V. ; Talypina, G. V.; Skurko, M. R. ; Bronnikova, G. V.; Ivanova, A. N. teaches The soiling of floors is reduced by adding 0.7- 1.5 wt.% product from incomplete esterification of maleated rosin with pentaerythritol as polyester resin (at rosin- maleic anhydride-pentaerythritol wt. ratios 67.0-71 .5: 19.0-22.0: 9.5- 1 1 .0) and also 0.3- 1 .8 wt.% 4-phenyl- 1 ,3-dioxane to the aq. em ulsion contg. Zn-contg. latex of a styrene- Et acrylate-methacrylic acid copolym er (based on dry residue wt.) 1 1 .0- 14.8, ethylene glycol 0.8- 1 .5, aq. NH ₃ 0.8- 1 .5, tributoxyethyl phosphate 0.8- 1 .4, polyethylene glycol alky Ipheny I ethers 0.1 -0.5, diethylene glycol monoethyl ether 1 .5-3.0, CF ₃ C0 ₂ H 0.004-0.010, Na pentachlorophenolate 0.04-0.20, and fragrance 0.05-0.5 wt.% . The rosin, m aleic, pentaerythritol weight ratios are different.

JP 50109927 teaches irradiation-curable unsaturated polyester resin coating compositions giving crack- resistant coating films, prepared from compositions comprising an unsaturated polyester containing rosin polyhydroxy alcoholic esters, an unsaturated diallyl ether 20 parts was polymerizedand diluted with styrene to give an unsaturated polyester solution (acid value 13.5 mg KOH/g, 65% resin) . A m ixture of maleic anhydride 12, triethylene glycol 50, propylene glycol 12 parts, and tetrahydrophthalic acid was polym erized, and diluted with styrene to give an unsaturated polyester soln. (acid value 18.6 mg KOH/g) , which (30 parts) was m ixed with the polyester solution containing rosin 70, styrene 20, PhMe ( 1 % silicone oil) 1 , and benzoin propyl ether 2 parts to give a coating composition. The coating composition was coated on a substrate previously treated with resin, dried 2 m in, exposed 3 m in to a fluorescent lamp (20 W) , and irradiated 60 sec with 1 -kW Hg lamp to give a crack- resistant coating film .

JP 2016199727 teaches polyester resin obtained by reacting (a) rosin, (b) a compound having > two carboxyl groups, (c) isosorbide, and (d) polyol (excluding isosorbide (c) ) . Thus, 34 parts resin (prepared by m ixing and heating 25 parts gum rosin, 15 parts terephthalic acid, 45 parts isosorbide, 15 parts neopentyl glycol, 60 parts xylene and 0.1 part p-toluenesulfonic acid monohydrate), 65.9 parts dipentaerythritol hexaacrylate and 0.1 part hydroquinone were admixed to obtain varnish and 63 parts of the obtained varnish, 20 parts Lionol Blue FG 7330, 11.9 parts di-trimethylolpropane tetraacrylate, 2.5 parts 4,4’-bis(diethylamino)benzophenone, 2.5 parts 2-methyl- 2-monopholino (4-thiomethylphenyl) propan-1 -one and 0.1 part hydroquinone were admixed to obtain the lithographic printing ink.

Zhongguo Suliao (2005), 19(9), 61 -63 teaches a synthetic method of rosin acid- modified terephthalic unsaturated polyester resin. The optimal reaction temperature was 230-240°. Terephthalic acid was reacted with glycols. When the acid value reduced to 19 ± 2 mg KOH/g, maleic anhydride was introduced and rosin acid was added as the acid value reduced to 60 ± 2 mg KOH/g. The terminating hydroxy groups were allowed to esterify at 190-200°. The solubility and reactivity of terephthalic unsaturated polyester resin were improved by rosin acid. Its reactivity with styrene was higher than dicyclopentadiene modified counterpart, the mechanical properties, thermal and chemical resistances were better than unmodified ones.

Sugaku, Shizen Kagaku (1956), 7, 13-18 teaches a polyester resin synthesized by the reaction of a maleic acid adduct of abietic acid with a triol obtained by the reduction product of the adduct. The reaction proceeded above 240°, and metallic Fe was a good catalyst. This resin was useful for coating.

Reguxing Shuzhi (2009), 24(4), 18-20 is directed to rosin terminated terephthalic unsaturated polyester resin (TUPR). The effect of different catalysts on the conversion rate of the reaction was investigated. The optimum compound and amount of catalyst were determined. The mechanical properties, thermal property and corrosion resistance of castings of the TUPR before and after modification and general orthophthalic unsaturated polyester wascompared. The results showed that the catalytic effect was best with the mass ratio of monobutyl tin oxide to stannous octoate 1 : 1 and amount 0.5% (based on the wt. of terephthalic acid). The mechanical property, corrosion resistance and water resistance of rosin modified TUPR were better than the orthophthalic resin, and the water resistance, alkali resistance and the compatibility with styrene of it were better than the unmodified TUPR.

JP2001233947 teaches polyester resin produced by reacting (a) rosin, (b) a polar-group-containing petroleum resin, (c) at least one substance selected from among aliphatic monohydric alcohols, aliphatic dihydric alcohols, aliphatic monoam ines, and aliphatic monoepoxides, and (d) a polyol. This prior art involves epoxy, am ine, polar petroleum resin such as DCPD resin.

JP 2018016688A teaches resin for active energy ray-curable inks containing a rosin-modified unsaturated polyester resin (A) . The rosin-modified unsaturated polyester resin (A) is a reaction product of a starting m aterial com ponent that contains rosins (a) , a,b- unsaturated carboxylic acids (b) and polyols (c) ; and the molar ratio of unsaturated bonds derived from the a,b- unsaturated carboxylic acids (b) relative to the total amount of the starting m aterial component is from 0.50 mol/kg to 2.00 mol/kg (inclusive) . The rosins (a) contain 90% by mass or more of a stabilized rosin relative to the total am ount of the rosins (a) ; the a,b- unsaturated carboxylic acids (b) contain a,b- unsaturated dicarboxylic acids; and the polyols (c) contain a tri- or higher hydric ale. This prior art rosin is a stabilization treated rosin which is a hydrogenated rosin or a disproportionated rosin but not a regular grade resin requiring no such pre-treatm ent. Further unsaturated polyester using the double bond of m aleic anhydride for radiation curing is used in this prior art.

US1903598A teaches halogenized products obtained in different ways wherein the initial products may be subjected to direct chlorination, if desired in the presence of suitable diluting agents; they m ay be subm itted to the action of chlorine in alkaline solutions. Or a solution of hypochlorite of soda may be added to the alkaline solutions of the respective acids and the chlorinated products then m ay be precipitated in the sam e way, as in chlorination by chlorine acting directly on alkaline solutions-by adding ’suitable acids, as for example dilute hydrochloric acid. These chlorinated products obtained in one way or another may be combined with a suitable hydroxy-acid. If the preparation of any hydroxy-acid is of no great difficulty, this acid may be used as a desirable component, the other chlorinated component corresponding following the nature of the used hydroxy- acid-or to the type of aleuritinie-acid or to the type of shellol-acid.

US2008103A teaches an oxidized resin, soluble in furfural and substantially insoluble at room tem peratures in ordinary petroleum naphthas, obtained from the molecular oxygen oxidation and subsequent naphtha precipitation of a liquid m ass com prising a m ineral drying oil and consisting of the residue resulting from the polymerization of cracked gasoline.

US3912690A dislcoses alcohol soluble polym eric sealant vehicles produced synthetically by reaction of a polyol having at least three reactive hydroxyl groups with at least one aromatic acid anhydride, the latter class in not more than stoichiom etric relation to the hydroxyls of the polyol, opening the anhydride ring thereof by partial esterification without water form ation at temperatures below the esterification range. Thereafter, free carboxyl groups then present are predom inantly esterified by further reaction with at least one epoxide monomer preferably having both an epoxy group and another functional group. The latter epoxide combination most often includes as a part thereof reactant monom ers containing as the sole functional group one epoxide group, monom ers containing two epoxide groups, and monom ers containing an epoxide group and a reactive hydroxyl group. I n any event, selection and stoichiometric relation of the reactants in the final polymer are such that the final unreacted hydroxyl percent by weight of the completed polymer is at least eight percent to provide requisite alcohol solubility. These polym ers are further unusual in that they are of relatively uniform and pre-calculatable molecular weight.

US6583263 is directed to acrylated maleic-modified rosin esters and methods of preparing sam e for introducing acrylic functions into high molecular weight natural resins, under m ild conditions, without the risk of gellation.

US3497490A teaches m aleation of tall oil rosins relating to the manufacture of high acid number tall oil rosins and polyhydric alcohol esters thereof by reacting these rosins with alpha-beta unsaturated lower olefin dicarboxylic acids or anhydrides such as m aleic acid or anhydride or fum aric acid. This prior art teaches an improvement in these processes wherein a small but effective amount of a lower saturated aliphatic monocarboxylic acid or an anhydride thereof is present in the reaction to avoid difficulties due to the evolution of a sublimate.

Preparation and properties of maleopimaric neopentyl glycol ester polyol is taught by YANG Cheng-wu, et al. in Journal of Nanjing University of Technology (Natural Science Edition) 2007-01 is directed to maleopimaric anhydride (MPA is prepared by reaction of maleic anhydride and purified abietic acid) which had good thermal stability, was mostly investigated as raw material for preparation of heat resistant polyol. In order to obtain better thermal stability products, polyester polyol was synthesized through the reaction of MPA with neopentyl glycol (NPG) which had heat resistant functional group. The change of acid value of reaction system was studied in details. Some kinds of products which had extensive range of hydroxyl value were prepared by changing the molar ratio of NPG/ MPA. I R spectroscopy and thermal stability of products were discussed respectively. It was found that all carboxyl groups of MPA were esterified. The products which had high onset degradation temperature could be used as a heat resistant raw material. Rosin contains multiple molecules in addition to abietic acid. In this reference purified abietic acid is used. Further states that the carboxyl groups of the MPA (Maleopimaric anhydride) are completely consumed and resins with a range of hydroxyl values are prepared.

Reactive and Functional Polymers July 2007 67(7) : 617-626 DOI:

10.1016/ j. react fund poly m.2007.04.001 teaches unsaturated polyester resin (UP), based on 1 mol maleopimaric adduct (MPA), 1 mol maleic anhydride, 1 mol isophthalicacid, 1 mol adipic acid, 1 mol propylene glycol, and 1 mol diethylene glycol, were obtained at various times during polyesterification. The compatibility of the produced unsaturated polyester resin with styrene was tested with I R and NMR and along with time of the reaction. The curing behaviors of cured UP resins with styrene were evaluated by DSC measurements. This reference thus teaches an unsaturated polyester where the maleic anhydride unsaturation is left unreacted in the polyester for further reaction with styrene. US3497490A is directed to maleation of tall oil rosins that relates to manufacture of high acid number tall oil rosins and polyhydric alcohol esters thereof by reacting these rosins with alpha-beta unsaturated lower olefin dicarboxylic acids or anhydrides such as maleic acid or anhydride or fumaric acid. More particularly, the invention provides an improvement in these processes wherein a small but effective amount of a lower saturated aliphatic monocarboxylic acid or an anhydride thereof is present in the reaction to avoid difficulties due to the evolution of a sublimate. Rosin, maleic anhydride and a small quantity of acetic anhydride, propionic anhydride, acetic or propionic acid or other lower saturated aliphatic monocarboxylic acid is used to prevent sublimation products of tall oil rosin which leads to difficulties in processing, this prior art being restricted to tall oil rosin.

US3106550A is directed to high softening point maleic modified tall oil rosin glycerol esters relating to polyhydric alcohol esters of maleic acid reacted in limited proportions with rosin by Diels- Alder reaction to form adducts in the form of rosin esters and more particularly, the prior art relates to preparation of maleic dienophile adducts with rosin selected from the group consisting of tall oil rosin, wood rosin and gum rosin, the maleic esters of the polyhydric alcohol being prepared in a molar proportion of about 1.5-2.6 moles of polyhydric alcohol per mol of maleic anhydride or maleic acid and thereafter reacting the so formed ester with said rosin.

Reference is invited to US1756819A onresinoid non-crystalline plastic, US1942413A on Batu gum, rosin polymerized and blended with chinawood oil and drier, US2101398A teaching mastication of Gum Copal under heat and Pressure, US2359972A on thermoplastic compositions having chemical and physical properties corresponding closely to those of shellac, and hence adapted to at least partially replace shellac in many of its applications, particularly in the manufacture of sound reproducing records, US2396608A teaches Nitration of Rosin salts (Potassium, Ammonium). In view of the above conventional knowledge on rosin, shellac, gum copal there is a need in the art to explore for binders and formulations comprising the same that would be adapted for coating compositions including wood polish applicable as a single component system would have high shelf stability without a settling tendency, dissolve in com mon solvents such as alcohol, ketone, ester to give a clear solution without precipitation, would provide for fast drying haze free finish, provide for high glossy coating > 90 units gloss at 60 deg angle, would provide excellent grain filling on wood, would be isocyanate, form aldehyde and epichlorohydrin free, would have good water and stain resistance, and would be a cost effective substitute for high cost shellac, gum copal and would favour recoatability with com mon solvent/water borne topcoats such as alkyd, urethane alkyd, m elam ine form aldehyde, polyurethane.

OBJECTS OF TH E I NVENTI ON

The primary obj ect of the present invention is to provide for binder and coating form ulations thereof as econom ical substitute to high cost resins such as Shellac and Gum Copal with consistent lot to lot properties, free of im purities, excellent water and stain resistance.

Another object of the present invention is to provide for said binder and coating form ulations thereof that would provide for one pack ambient curing and fast drying polish with excellent grain filling and high gloss on wood (> 90 units at 60 deg) Yet another object of the present invention is to provide for Epichlorohydrin, form aldehyde and isocynate free binder and coating form ulations thereof that would be compatible in com mon solvents such as alcohols, esters, ethers, ketones.

Another object of the present invention is to provide for said binder and coating form ulations thereof that would be recoatable with com mon solvent/water borne topcoats such as alkyd, urethane alkyd, m elam ine form aldehyde, polyurethane.

SUMMARY OF TH E I NVENTI ON

Thus according to the basic aspect of the present invention there is provided m aleated rosin modified polyester resin form ulation comprising partially maleated rosin and polyols including Tri- and Tetra- functional polyols, said resin having Acid Value of 60- 105 mg KOH/g, Hydroxyl value < 40 mg KOH/g. Preferably said m aleated rosin modified polyester resin form ulation comprises polyol esterified partially maleated rosin, esterified with Tri- & Tetra- functional polyols, and involves 97-98% consum ed hydroxyl groups of polyols resulting in said resin with 60 to 105 mg KOH/g Acid value, < 40 mg KOH/g Hydroxyl value, 60- 100 °C Tg (glass transition temperature) , Mn (num ber average molecular weight) = 500- 1500, PDI (polydispersity index) > 10.

According to another preferred aspect of the present invention there is provided said maleated rosin modified polyester resin form ulation wherein said partially m aleated rosin modified polyester resin form ulation comprises native rosin (60 to 80% by weight on polymer solids) free of any pre-treatm ent, Maleic anhydride (5 to 15% by weight on polym er solids) , tri- and tetra- functional polyols 5-20 % by wt on polym er solids preferably including trimethylolpropane, pentaerythritol ( 10 to 20% by weight on polym er solids) ; and wherein said Rosin/Maleic functionality is in the ratio of 1 0.5 on molar basis.

Preferably said m aleated rosin modified polyester resin form ulation is provided wherein said tri- functional polyol is included in higher levels as compared to tetra functional polyol with the weight percent of said trifunctional polyol to the tetrafunctional polyol preferably > 50 wt.% .

More preferably said m aleated rosin modified polyester resin form ulation is provided wherein said partially m aleated rosin modified polyester resin form ulation comprises said polyol esterified maleated rosin, which said polyols comprise polyacid esterified tri and tetra functional polyols, said polyacids selected from phthalic anhydride, isophthalic acid, cyclohexane dicarboxylic acid, terephthalic acid According to another preferred aspect of the present invention there is provided m aleated rosin modified polyester resin form ulation wherein said partially m aleated rosin modified polyester resin form ulation comprises 60 to 80% Rosin, 5 to 15% Maleic anhydride, 10 to 20% tri and tetra functional polyols and 2 to 15% by weight of polyacid inlcuding phthalic anhydride or isophthalic acid (preferably 5 to 10% by weight of polyacid) .

According to yet another preferred aspect of the present invention there is provided m aleated rosin modified polyester resin form ulation optionally involving di-functional polyol, unsaturated fatty acid or oils including linseed oil, phenolic compounds including cardanol upto 5 % by wt. on polymer solids said form ulations com prising 50 to 60% of Rosin, 5 to 15% of Maleic anhydride, 10 to 20% of tri and tetra functional polyols optionally, including 1 to 10% of di functional polyol, or 1 to 10% of unsaturated fatty acid or oils or 5 to 10% of polyacid.

Advantageously, said m aleated rosin modified polyester resin form ulation is provided wherein said rosin is partially maleinized involving Rosin: Maleic acid at 1 : ~ 0.5 molar ratio providing for Diels Alder adduct reactive with polyols to preferably favour saturated polyester resin with consumed maleic anhydride unsaturation due to Diels Alder reaction with Rosin and said polyester resin with 97-98% consum ed/reacted hydroxyl groups of polyols enabling resin compatibility with other resins including Gum Copal, Shellac and com patibility in different organic solvents including alcohols, ketones, glycol ethers, esters, ethers, aromatics as applicable for coating form ulations.

Preferably, said maleated rosin modified polyester resin form ulation is provided wherein said polyol includes tri and tetra functional polyols including difunctional polyols MP diol, neopentyl glycol, ethylene glycol, propylene glycol, glycerol, TMPD, hexandiol, cyclohexanedim ethanol; and said polyacids comprises cyclohexane dicarboxylic acid, terephthalic acid, phthalic anhydride, isophthalic acid. According to another preferred aspect of the present invention there is provided said maleated rosin modified polyester resin as one pack ambient curing coating form ulation comprising said maleated rosin modified polyester resin in organic solvents including alcohols, ketones, glycol ethers, esters, ethers, aromatics comprising 10-25 wt. % of said maleated rosin modified polyester resin with organic solvents 75 to 90 wt. % including alcohols, ketones, glycol ethers, esters, ethers, aromatics. Preferably said maleated rosin modified polyester resin as one pack ambient curing coating formulation is provided including an aerosol variant with a propellant including either one of or a mixture of hydrocarbons such as propane, n-butane, iso-butane or ethers such as dimethyl ether, methyl ethyl ether, and a combination of high and low vapor pressure solvents selected from alcohols, ketones, glycol ethers, esters, ethers and aromatics wherein said coating provides excellent water resistance (24 hours, spot test pass), excellent grain filling, high gloss, fast drying, excellent sanding without clogging, recoatable with common solvent/water borne topcoats such as alkyd, urethane alkyd, melam ine formaldehyde, polyurethane, compatible with resins such as Rosin, Gum Copal and Shellac.

According to another aspect of the present invention there is provided a process for the preparation of maleated rosin modified polyester resin comprising the steps of: providing rosin free of any pre-treatment and reacting with Maleic anhydride to provide for an adduct; esterifying the above adduct with tri and terta functional polyols in t he presence of esterification catalyst, optionally involving di-functional polyol, unsaturated fatty acid or oils including linseed oil, phenolic compounds including cardanol and obtaining said maleated rosin modified polyester resin. Preferably in said process said tri and terta functional polyols are optionally esterified with polyacids selected from phthalic anhydride, isophthalic acid, cyclohexane dicarboxylic acid, terephthalic acid; and wherein said esterification catalysts include organotin compounds, titanium orthoesters. According to yet another preferred aspect of the present invention there is provided a process comprising the steps of: reacting rosin (60 to 80% by weight on polymer solids) with Maleic anhydride (5 to 15% by weight on polymer solids) and obtaining partially maleinized rosin as an adduct to favour saturated polyester resin with consumed maleic anhydride unsaturation; esterifying the above adduct with tri and terta functional polyols (10 to 20% by wt of polymer solid) consuming 97-98% of the hydroxyl groups to obtain said maleated rosin modified polyester resin therefrom.

Preferably, a process in provided wherein said formulations for adduct formation and esterification reaction comprises 50 to 60% of Rosin, 5 to 15% of Maleic anhydride, 10 to 20% of tri and tetra functional polyols esterified with polyacids selected from phthalic anhydride, isophthalic acid, cyclohexane dicarboxylic acid, terephthalic acid; optionally including 1 to 10% of di functional polyol, or 1 to 10% of unsaturated fatty acid or oils or 5 to 10% of polyacid for obtaining said maleated rosin modified polyester resin therefrom.

BRI EF DESCRI PTI ON OF FI GURES

Figure 1 : illustrates (a) Shellac with its known glossy characteristics applied on wood panel (left) ; and (b) Polyester coating applied according to the invention (right) . DETAI LED DESCRI PTI ON OF THE I NVENTI ON

As discussed hereinbefore the present invention provides for maleated rosin modified polyester resin formulations and a process of preparation thereof. While the modification of rosin by Diels-Alder condensation with alpha-beta unsaturated olefin dicarboxylic acids such as maleic acid or anhydride are used for several purposes, and when relatively large proportions of aliphatic dicarboxylic acid or anhydride are used, such as about to 25% on the weight of the rosin, adducts are obtained that are useful in the preparation of varnishes, lacquers and inks. Thus, for example, rosin-maleic acid adducts having high acid numbers on the order of 260-330 and are used in steam-set inks and, after esterification with glycerol, ethylene glycol, pentaerythritol or other polyhydric alcohols, in the preparation of varnishes, lacquers, floor polishes and other surface coatings but have inherent problems of water resistance, gloss, drying time required which the present invention tries to meet.

Maleic Modified Rosin Resins are conventionally of 3 types (Ref: The Printing Ink Manual, By Robert Leach, Springer)

The present invention, however, relates to binder and coating formulations thereof comprising maleated rosin modified polyester resin which can be applied as a single pack system not only meeting but even exceeding properties of natural resins such as shellac with regard to gloss, grain filling and water resistance.

Thus the present invention satisfies the need for polish including wood polish which can be: 1 . Made Available as a single pack system meeting and even exceeding properties of natural resins such as shellac with regards to gloss, grain filling and water resistance / applicable as a single component system ; 2. Have high shelf stability without a settling tendency; 3. Dissolve in com mon solvents such as alcohol, ketone, ester to give a clear solution without precipitation; 4. Fast drying haze free finish; 5. Glossy coating > 90 deg gloss at 60 deg angle; 6. Excellent Grain filling on wood; 7. Isocyanate, form aldehyde and epichlorohydrin free; 8. Good water and stain resistance; 9. Low cost natural resin (shellac, gum copal) substitute; 10. Recoatable with com mon solvent/water borne topcoats such as alkyd, urethane alkyd, melam ine formaldehyde, polyurethane.

Conventionally while shellac in alcohol is applied as a wood polish. To improve gloss and water resistance, Gum Copal (resin) is blended. To reduce cost , Rosin is blended. Rosin for the purposes of the present invention is procured from a chem ical company with the following specifications Acid value = 150 to 200 mg KOH/g, softening point of 60 to 90 °C, a clear solution in toluene with a color of 0 to 10 on Gardner scale (for a 50% solution in toluene) . The product of the present invention and process thereof involves maleinization of the Rosin, followed by reaction with tri and tetra functional polyols. Optionally other polyacids such as phthalic anhydride, isophthalic acid etc. can be used for esterification.

Significant advantages of the present invention being i. Epichlorohydrin free, form aldehyde and isocynate free; ii. Excellent water resistance (24 hours, spot test pass) ; iii. Excellent grain filling ; iv. High gloss > 90 units at 60 deg ; v. one pack ambient curing; vi. fast drying < 5 m inutes touch dry; vii. Excellent sanding without clogging ; viii. Recoatable with com mon solvent/water borne topcoats such as alkyd, urethane alkyd, m elam ine formaldehyde, polyurethane; ix. Compatible with natural resins such as Rosin, Gum Copal and Shellac.

The m anufacture of the maleated rosin modified polyester resin selectively involves malenization of the Rosin ( regular grade requiring no pre-treatm ent) , followed by reaction with both tri and tetra functional polyols, optionally esterifying with other polyacids such as phthalic anhydride, isophthalic acid etc. The invention provides primarily saturated polyester where the maleic anhydride unsaturation is consumed during the Diels Alder reaction with Rosin.

While conventionally shellac in alcohol is applied as a wood polish , to im prove gloss and water resistance as well as cost reduction Gum Copal resin is selectively blended. A com parative of properties of the m aleated rosin modified polyester resin of the present invention with shellac and Gum Copal are provided in the following Table 1 .

Table 1 : The product and process of the present invention thus provide for the advantages of the binder and the form ulation/ com position thereof thus attained as per the following: a) Epichlorohydrin free, formaldehyde and isocynate free b) Excellent water resistance (24 hours, spot test pass) c) Excellent grain filling d) High gloss > 90 units at 60 deg the photograph of the coating in com parison with Shellac is given in Figures 1 a and 1 b. e) one pack ambient curing f) fast drying < 5 m inutes touch dry g) Excellent sanding without clogging g) Recoatable with com mon solvent/water borne topcoats such as alkyd, urethane alkyd, melam ine formaldehyde, polyurethane h) Compatible with resins such as Rosin, Gum Copal and Shellac.

According to an aspect of the present invention there is provided a polyester binder resin comprising Rosin (50 to 80% by weight on polymer solids), Maleic anhydride (2 to 15% by weight on polymer solids), tri and terta functional polyols such as trimethylolpropane, pentaerythritol (5 to 20% by weight on polymer solids) and optionally polyacids such as phthalic anhydride, isophthalic acid (2 to 15% by weight on polymer solids) providing for binder polyester resin having an acid value of 60 to 105 mg KOH/g and a hydroxyl value of 0 to 40 mg KOH/g. More preferably the Rosin content is (60-80% by weight on polymer solids), Maleic anhydride content is (5 to 15% by weight on polymer solids) , tri and tetra functional polyols are (10-20% by weight). The Acid value is more preferably 70- 90 mg KOH/g and the hydroxyl value is more preferably 0 to 20 mg KOH/g.

The number average molecular weight is 500 to 2000 g/mol and the polydispersity index is 10 to 40. The number average molecular weight is more preferably 500 to 1500 g/mol. The glass transition temperature of the polyester is 60 to 100 deg C. The coating form ulation comprises 10 to 25% of this polyester resin. Organic solvents (75 to 90% by weight) such as alcohols, ketones, glycol ethers, esters, ethers, aromatics are employed. A combination of high and low vapor pressure solvents are preferred to attain the desired application properties and drying time. According to another aspect of the present invention there is provided said polyester resin binder wherein 5 to 10% of the Rosin is substituted with unsaturated fatty acid or unsaturated oils such as linseed oil or phenolic compounds with unsaturation such as cardanol. According to another preferred aspect of the present invention there is provided said resin binder comprising polyols such as MP diol, neopentyl glycol, ethylene glycol, propylene glycol, glycerol, TMPD, hexandiol, cyclohexanedimethanol. Other multifunctional polyols such as Dipentaerythritol can also be used. Preferably, said polyester resin binder may contain other polyacids such as cyclohexane dicarboxylic acid, terephthalic acid.

More preferably said coating formulation may optionally contain 10 to 50% of natural resins such as Rosin, Gum Copal, Shellac as a blend on polymers solids.

Preferably the coating form ulation comprises common additives such as flow and leveling agents, cosolvents, defoamers, biocides, rheology modifiers, wetting and dispersing additives and fillers.

Different types of Rosin can be used for the invention. Wood rosin, rubber rosin, gum rosin, tall oil rosin and their combinations can be used for the preparation of the polyester. Various esterification catalysts such as Organotin compounds and titanium orthoesters are used for preparation of the polyester resin.

The coating application on wood can be done by brush, ragging with muslin cloth or spray application.

An aerosol variant has also been prepared with a propellant and optim ization of the solvent composition. The propellant (either one of or a m ixture of hydrocarbons such as propane, n-butane, iso-butane or ethers such as dimethyl ether, methyl ethyl ether) can be used. A combination of high and low vapor pressure solvent chosen from alcohols, ketones, glycol ethers, esters, ethers and aromatics enable formulation of the aerosol variant. Exam ple 1 : Maleated rosin modified polyester resin

Partial m aleinization of Rosin ( Rosin : Maleic 1 : ~ 0.5 on molar basis) to prepare a Diels Alder adduct which is then esterified with polyols to consume 97-98% of the hydroxyl groups of the polyol resulting in resin with 70 to 90 mg KOH/g Acid value, < 20 mg KOH/g Hydroxyl value, 60- 100 °C Tg, Mn = 500- 1500, PD I > 10.

To determ ine Hydroxyl Value and acetylable matter the following procedure was followed.

1 ) Mix 10.5 m l of acetic anhydride with 100 m l of Pyridine.

2) Weigh sample accurately into 250m l Erlenmeyer flask with attached condenser ground joint. Add 25m l of the acetylation reagent into the flask with the help of pipette. Swirl the contents of the flask to dissolve the sam ple. Heat at reflux for 30-45 m inutes. Allow the flask to cool. Rinse the condenser with 25 m l of water. Remove the condenser and rinse the joint of the condenser and the flask with water collecting in the flask. Cool the flaks in a icewater bath so that the contents are below 20 deg cent , add 0.5 to 1 .0 m l of Phenolphthalein indicator solution and titrate slowly with 0.5N aqueous NaOH solution to the first perm anent faint pink end point.

Perform a blank determ ination in parallel by the same procedure.

Calculate the hydroxyl content as follows :

( B - V ) x N x 17.01

Hydroxyl % x 100

( S x 1000 ) where,

V = m l of the NaOH required for titration of sample. B = m l of NaOH required for the titration of blank N = Normality of NaOH solution S = gm of the sam ple used. ( B - V ) x N x 56.1

Hydroxy value = ^.

S

To determ ine Acid Value the following procedure was followed:

1 ) Solvent m ixture containing two parts of toluene and one part of ethanol by volume - neutralize with alcoholic potassium hydroxide prior to using, with phenolphthalein indicator.

2) Potassium Hydroxide - 0.1 M in methanol or ethanol.

3) Ethanol - anhydrous

4) Toluene anhydrous

5) Phenolphthalein - 1 % in Ethanol

Procedu re:

Weight sam ple nearest to 0.1 mgm as indicated in table in 250 m l conical flask. Add 50 m l of neutralized solvent m ixture. Mix till sample is dissolved. Titrate with Potassium hydroxide solution from bu rette until red coloration j ust appears and is stable for atleast 10 seconds while the solution is stirred.

56.1 x M x V

Acid Value = ^.

W

M = Molarity of KOH V = m l of KOH consumed in titration W = weight of sample in gm .

Exam ple 2 : Form ulation of the coating

The coating com position contains 10 to 25% of this polyester resin and Organic solvents (75 to 90% by weight) such as alcohols, ketones, glycol ethers, esters, ethers, aromatics Table 2: Examples of the Polyester Resin formulations It is thus the surprising finding of the present invention that when both Tri- & Tetra- functional polyol conj ugation/ esterification with partially maleated rosin is achieved when said partially maleated rosin consumes the hydroxyl groups of the Tri- & Tetra- functional polyols, with said tri-functional polyol employed in higher amounts over tetra-functional polyols, preferably > 50 wt.% amounts as compared to tetra-functional polyols, the dersired acid value and hydroxyl value could be reached enabling good property performance thus not only meeting but even exceeding properties of natural resins such as shellac with regard to gloss, grain filling and improved water resistance. Also it was found by involving di-functional polyol in com bination the rosin content could be further reduced to m eet closely equivalent properties and comparable gloss such as in Table 2 composition 7 above vis-a-vis com position 1 & 2.

Table 3: Examples of the Coating Formulation:

Table 4: Example of Shellac Coating Formulation Exam ple 1

Resin preparation: Rosin (71.64 grams) and Maleic Anhydride (17.91 grams) are charged into a 4 neck reactor equipped with stirrer, condenser, separator and thermocouple to carry out the Diels-Alder reaction at 180°C for 60 minutes by continuous mechanical stirring under nitrogen purging. Then Pentaerythritol (9.95 grams) and o-xylene (0.5 grams) is charged into above reaction m ixture at 100°C. Temperature is gradually raised to 250 °C. The esterification reaction is continued till the desired acid value and hydroxyl value is achieved. The temperature is reduced to desired level followed by solvent thinning. The obtained resin displays a molecular weight (Mn) of 457 g/mol and polydispersity index of 3.63. The Acid value of the resin is 186 mg KOH/g. The formu la and properties of the resin are given in Table 2.

Coating preparation: The above polyester resin is thinned to 15% solids with a specific solvent combination of o-xylene (1 gram) , Diacetone Alcohol (3 grams), Methyl Ethyl Ketone (27 grams) , Ethyl acetate (24 grams) and Isopropyl alcohol (30 grams) in the reactor as shown in Table 3. The coating was applied on teak wood panels of 1 feet by 1 feet dimensions under 50% relative humidity and ambient temperature (30 °C). The system gave comparatively improved visual gloss, similar drying time, sanding, grain filling and water resistance as compared to the shellac based polish system. The properties are given in Table 2.

As a comparison, Shellac flakes were dissolved in a mixture of alcohols (Table 4) and applied on teak wood panel (1 feet by 1 feet). The ratings are as follows: drying time is 5 m inutes, visual gloss rating of 7, water resistance rating of 5, grain filling is 8, sanding is 9.

Testing of coating: Ten coats are applied at an interval of 5 to 10 minutes on a 1 feet by 1 feet teak wood panel under 50% relative humidity and ambient temperature (30 °C) . the application of the polish can be done by dipping a m uslin cloth in the coating and ragging on the wood panel. The gloss, sanding, grain filling and water resistance are given on a scale of 1 to 10 (the higher the better) . The water resistance is tested by keeping a cotton soaked in water on the coating (soaked cotton is covered with a lid) for a period of 24 hours and then water damage to the coated is observed. A rating of 1 to 10 is given ( 1 indicating water whitening and film damage and 10 indicating that the film is unaffected) . Sanding was checked with a 320/400 mesh sand paper after 2 hours of applying the coating. Gloss is checked using a glossometer. A rating of 9 for gloss corresponds to a gloss of > 90 units at 60 degree angle.

Exam ple 2

The example 2 followed the same synthesis procedure as that of example 1. The composition is given in Table 2. The resin exhibited an acid value of 154 mg KOH/g, a hydroxyl value of 43 mg KOH/g and a molecular weight of 492 g/mol. The properties of the resin and the coating are given in Table 1. The coating was prepared as described in example 1 (Table 3) . The coating properties are similar to that obtained for example 1.

Exam ple 3 The example 3 followed the same synthesis procedure as that of example 1. The Acid value of the polyester resin was 98 mg KOH/g and the molecular weight (Mn = 825). There is an improvement in the water resistance of the coating from 5 to 7.

Exam ple 4 The example 4 followed the same synthesis procedure as that of example 1. Benzoic acid was used as a partial substitution for Rosin. The Acid value of the polyester resin was 103 mg KOH/g and the molecular weight (Mn = 624). The drying time slowed down to 10 minutes and the sanding dropped to a rating of 7.

Exam pies 5 and 6 The procedures followed for the above approaches were adopted for the example 5 and 6. Phthalic anhydride was incorporated in example 5 and 6. The acid value of polyester 5 is 102mg KOH/g exhibiting coating properties similar to example 3. The acid value of example 6 is 87 mg KOH/g and hydroxyl value of 15 mg KOH/g. There is a significant improvement of the visual gloss to a rating of 9 while showing improved water resistance compared to the shellac based design.

Exam ple 7

A glycol Neopentyl glycol was introduced to take part in the esterification reaction alongwith other polyols and polyacids. This led to a drop of the polydispersity index to below 10 even though the Acid Value for this example is the same as example 6. There was a decrease in the gloss of the coating as compared to example 6.

Exam ple 8 Raw Linseed oil was charged along with rosin and maleic anhydride to take part in Diel- alder reaction. The esterification reaction continued in the similar manner as mentioned in above examples. This rosin ester exhibited very high visual gloss and grain filling as shown in Table 2.

Exam pies 9 Cardanol was used instead of Raw Linseed oil. Even this rosinated polyester helped in improving the gloss to a higher level. But it slowed down the drying time to 10 m inutes.

Thus by the way of the present invention maleated rosin modified polyester resin binder with Acid Value of 60 to 105 mg KOH/g, Hydroxyl value < 40 mg KOH/g, Tg (glass transition temperature) in the range of 60- 100°C as measured by DSC, Mn = 500- 1500, and PD I > 10 is obtained compatible with alcohols, ketones, glycol ethers, esters, ethers, aromatics, which upon formulation provides fast drying, high gloss, excellent water resistant, economical alternate to high cost natural resins such as Shellac and Gum Copal with consistent lot to lot properties, free of natural impurities composition.