Claims:We Claim:
1. Cardanol polyol modified alkyds comprising amine functional cardanol polyol grafted into the alkyd backbone, said cardanol polyol being polyhydroxy derivative of cardanol having hydroxyl value in the range of 150-350 mg KOH/g.

2. Cardanol polyol modified alkyds as claimed in claim 1 wherein said polyhydroxy derivative of cardanolincludes cardanol mono glycidyl ether reaction product ofamino alcohols.

3. Cardanol polyol modified alkyds as claimed in claims 1 or 2 that is air drying and comprises a condensation product of polyhydroxy derivative of cardanol with drying/semi drying vegetable oils or their fatty acids, cycloaliphatic/aromatic carboxylic acid, cycloaliphatic /aromatic carboxylic anhydride and polyols adapted to impart hydrophobicity to the alkyd polymer back bone favouring enhanced water, acid, alkali and corrosion resistance characteristics.

4. Cardanol polyol modified alkyds as claimed in claims 1-3 wherein said amino alcohols include Di ethanol amine, 2amino-2 methyl-1 propanol, ethanolamine capable of further reaction with cardanol derivative having oxirane group.

5. Cardanol polyol modified alkyds as claimed in claims 1-4 wherein saiddrying/semi drying vegetable oils include Soya bean Oil, Dehydrated castor Oil, Linseed Oil, Tung Oil, Safflower seed Oil, sunflower Oil, Tall Oil, Cotton seed Oil, Rubber seed Oil and their fatty acids having iodine value in the range of 120-180 gI2/100g; dicarboxylic acid/anhydride includes phthalic anhydride, Isophthalic acid, Terephthalic acid, trimelliticanhydride, hexahydro phthalic anhydride, tetrahydro phthalic anhydride, maleic anhydride, succinic acid , adipic acid and preferably Phthalic anhydride; chain terminatingcycloaliphatic /aromatic carboxylic acid include benzoic acid, Para tertiary butyl benzoic acid, cyclohexane carboxylic acid,abietic acid (rosin) and preferably benzoic acid; polyols includetrimethylpentane diol, ethylene glycol, diethylene glycol,2-methyl-1,3-propanediol, 2-Butyl-2-Ethyl-1,3-Propanediol,neopentylglycol, glycerol, pentaerythritol, trimethylol ethane, trimethylol propane or similar and preferably pentaerythritol.
6. Cardanol polyol modified alkyds as claimed in claims 1-5 having an acid number of <12 mg KOH/g preferably in the range of 5-10 mg KOH/g having clarity and viscosity of Y-Z, Z-Z4@ 54-56% Non Volatiles, and is MTO (mineral turpentine oil) thinnable adapted for metal glossy enamel as well as coating systems comprising primer & top coat providing said improved water, acid, alkali and Salt spray resistance properties.
7. Cardanol polyol modified alkyds as claimed in claims 1-6 wherein said grafted cardanol polyol alkyd backbone involves amine functional cardanol polyol that partly substitutes said polyols in said alkyd backbone favouring said improved water, acid, alkali and Salt spray resistance properties.
8. Cardanol polyol modified alkyds as claimed in claims 1-7 wherein said grafted cardanol polyol alkydis a condensation product of 30-55 wt% drying / semi drying vegetable oils or their fatty acids having iodine value of 120-180 g I2/100g, 15-25 wt% polyols preferably pentaerythritol, 20-26 wt% dicarboxylic acid/anhydride preferably Phthalic anhydride,0.5-5% chain terminating mono functional acid preferably benzoic acid and 3-15 wt% cardanol-polyol having hydroxyl value of 150-350 mg KOH/gpreferably of 225-275 mgKOH/g.
9. A process for the manufacture of Cardanol polyol modified alkyds as claimed in claims 1-8 comprising the steps of
Pr oviding cardanol polyol which ispolyhydroxy derivative of cardanol (cardanol-polyol) having hydroxyl value in the range of 150-350 mg KOH/g; and
Providing drying/semi drying vegetable oils or their fatty acids having iodine value in the range of 120-180 gI2/100g, aliphatic /aromatic carboxylic acid, aliphatic /aromatic carboxylic anhydride and polyols, in solvent and reacting until an acid number of <12 mgKOH/g is reached to obtain said cardanol polyol modified alkyds having hydroxyl value of 64-95 mg of KOH/g therefrom.
10. A process for the manufacture of Cardanol polyol modified alkyds as claimed in claim 9 that is obtained from following steps:
(i) Reacting 3-15 wt.% said cardanol polyol; with30-55wt% drying /semi drying vegetable oil or their fatty acids having iodine value of 120-180 g I2/100g, 15-25 wt% polyols preferably pentaerythritol, 20-26 wt% dicarboxylic acid/anhydride preferably Phthalic anhydride, 0.5-5% chain terminating acid preferably benzoic acid, 3-5% reflux solvent, taken into a four necked flask fitted with a stirrer, thermometer, nitrogen bubbler and Dean & Stark assembly for Azeotropic Distillation followed by slowing raise the batch temperature up to 200?C in 2-3 h wit h continuous removal of water of reaction;
(ii) Increasing the reaction temperature upto 245°C in 3-5 h until an acid value of <12 mg KOH/g is obtained;
(iii) Cooling the reaction mass to 130-170°C for thinning with MTO solvent at 55% solid and obtaining the resultant Cardanol polyol modified alkyds having acid value of 5-10 mg KOH/g and viscosity of Z-Z4 @ 54-56% Non Volatiles.
11. A process for the manufacture of Cardanol polyol modified alkyds as claimed in claims 9-10 wherein said Reflux solvent is selected from methyl amyl ketone, xylene, Solvent CIX and preferably Xylene.

12. A process for the manufacture of Cardanol polyol modified alkyds as claimed in claims 9-11 wherein when said alkyd is based on drying / semi drying Oil, said drying / semi drying Oil is charged together with part of polyol preferably pentaerythritol and dibutyl tin oxide and heated to 245-250?C to allow monoglyceride formation; followed by cooling the reaction mass to 180?C, followed by charging remaining ingredients including Pentaerythritol -II, Phthalic anh ydride, benzoic acid, Cardanol triol of diethanol amine and Xylene for reflux and heated to 240-245?C in 3-5 hr and maintained till acid value of < 12 mg KOH/g is reached;
Cooling the reaction mass to 130-170°C and diluted with MTO solvent at 55% solid to get Cardanol polyol modified alkyds having acid value of 5-10 mg KOH/g and viscosity of Z1-Z2 @ 54-56% Non Volatiles.

Dated this the 5th day of March, 2020 Anjan Sen
Of Anjan Sen and Associates
(Applicants Agent)
IN/PA-199

, Description:FIELD OF THE INVENTION
The present invention provides for cardanol polyol modified alkyds preferably air-drying alkyds involving cardanol polyol grafted onto alkyd backbone by partly substituting commonly used polyols including Pentaerythritol, trimethylol propane, glycerine and similar polyols. Said cardanol polyol grafted alkyd being reaction product of cardanol mono glycidyl ether and amino alcohols including diethanol amine. Advantageously, said cardanol polyol modified alkyd resins find end use and application in direct to metal glossy enamel topcoat as well as coating systems comprising of primer & topcoat providing excellent corrosion resistance properties.
BACKGROUND ART
The corrosion of metals is an enormous economic problem resulting in huge losses every year. Thus, efforts to develop more efficient and environmentally compliant methods to prevent corrosion have been ongoing across the globe. There are anti-corrosive paints available in the market based on epoxy, phenolic resin, chlorinated rubber, polyurethane, organic or inorganic zinc-rich coatings mainly for industrial use and these coating compositions are either 2K systems or use hazardous solvents/ ingredients.
Alkyd based topcoats have been used for variety of coating applications, but it has limited anti-corrosive performance. To improve the coating performance, composite system of primers and top coats have been used that too provide limited corrosion resistance in alkyd chemistry.
CN103755935 discloses a method of preparation of cardanol-modified alkyd wherein cardanol was reacted with fatty acid chloride and metal hydroxide followed by reaction with glycerin and phthalic anhydride.
CN101230121B describes formulation of tall oil modified phenolic resin for high performance primer. The resin comprises the phenol/ tertbutylphenol, formaldehyde, oxalic acid, tall oil, colophony with hexa (4-aldehyde phenoxy) cyclic triphosphonitrile.
CN103724185 is directed to Cardanol ether acid intermediate synthesized by using cardanol as raw material, and then the intermediate is used as raw material to synthesize the alkyd resin, not only reducing the cost of raw materials and the alkyd resin prepared has good performance in terms of heat resistance and hardness.
GB1279257 details about cashew nut shell liquid derivatives, e.g. cardanol glycidyl ether were reacted with polyacids and polyol to formulate alkyd resins having better adhesion, flexibility, and water resistance than conventional alkyd resins.
K. I. Suresh and V. S. Kishanprasad detailed about Synthesis, Structure, and Properties of novel polyols from Cardanol and Developed Polyurethanes in Industrial & Engineering Chemistry Research 44(13), May 2005 teaches monoglycidyl ether of cardanol prepared followed by ring opening to prepare the diol or reaction with diethanol amine to give a triol. Alternately, another triol was also prepared by reaction of the glycerol monochlorohydrin with cardanol.
Sylvain Caillol et al. reviews functionalization of cardanol towards bio-based polymers and additives in Article publish in Polymer Chemistry 5(9), October 2013. This review detailed about CNSL (cashew nut shell liquid) based derivative and there usage in different industrial applications like Plasticizers,Surfactants, Doping agents, Antioxidants, Rubber modifiers, Addition monomer Polyol and polyurethanes Benzoxazine resins, Cyanate ester resins, Vinyl ester polymers, Phenolic resins &Epoxy resins.
Ton That Minh in Journal of Applied Polymer Science 65(3):507-510, July 1997 detailed about synthesis of cardanol based polyol and their subsequent use to formulate polyurethane films in an article Cardanol-glycols and cardanol-glycol-based polyurethane films.
Journal of Chemical Engineering March 2016, Volume 33, Issue 3, pp 1088–1094, synthesized cardanol polyol by reacting mono glycidyl ether of Cardanol and amino alcohols and such cardanol polyols have been used to prepare polyurethane foam, & Industrial & Engineering Chemistry Research (2005)44(13) 4504-4512 teaches polyurethanes out of it.
In another prior art, Designed Monomers and Polymers 2017, 20(1), 177 teaches cardanol polyol cured with Melamine formaldehyde resin and characterized for cure kinetics.
While there are no references in prior arts indicating use of cardanol triol for alkyd synthesis such that cardanol-polyol can be partly substituted replacing commonly used polyol for the synthesis of air-drying, MTO thinnable alkyd, there is a need in the art to provide for air-drying cardanol polyol modified alkyds incorporating special select functionality in the alkyd backbone capable of increased water, acid , alkali and corrosion resistance.
Hence, there is a need to incorporate special functionality into alkyd backbone to achieve enhanced corrosion resistance performance providing minimum 600-650 hours of salt spray resistance in ASTM B117 at a dry film thickness of 45-55 micron on bare mild steel.
OBJECTIVES OF THE INVENTION
It is the basic object of the present invention to provide for air-drying cardanol polyol modified alkyds and coating compositions thereof involving cardanol polyols grafted onto alkyd backbone; said cardanol polyols enabling part substitution of commonly used polyols including Pentaerythritol, trimethylol propane, glycerine and similar polyols.
It is another object of the present invention to provide for said air-drying cardanol polyol modified alkyds that would be MTO (mineral turpentine oil) thinnable and cardanol polyol modified alkyd resin having excellent corrosion resistance properties for direct to metal (Mild steel) application.
It is yet another object of the present invention to provide for protective coatings for decorative and industrial applications especially for mild steel that would circumvent the prior art problems of employing general epoxy, polyurethane, organic or inorganic zinc-rich coatings that are being offered as 2K systems containing hazardous solvents and essentially require multi coat system.
It is still another object of the present invention to provide for cardanol-polyol modified alkyd based coating composition that would be air-drying, MTO thinnable and can be directly applied on metals as top coat with high gloss and excellent anti-corrosive properties.
SUMMARY OF THE INVENTION
Thus according to the basic aspect of the present invention there is provided cardanol polyol modified alkyds comprising amine functional cardanol polyol grafted into the alkyd backbone, said cardanol polyol being polyhydroxy derivative of cardanol having hydroxyl value in the range of 150-350 mg KOH/g.
Preferably in said cardanol polyol modified alkyds said polyhydroxy derivative of cardanolincludes cardanol mono glycidyl ether reaction product ofamino alcohols.
More preferably said cardanol polyol modified alkyds are provided that is air drying and comprises a condensation product of polyhydroxy derivative of cardanol with drying/semi drying vegetable oils or their fatty acids, cycloaliphatic/aromatic carboxylic acid, cycloaliphatic /aromatic carboxylic anhydride and polyols adapted to impart hydrophobicity to the alkyd polymer back bone favouring enhanced water, acid, alkali and corrosion resistance characteristics.
According to another preferred aspect of the present invention there is provided said cardanol polyol modified alkyds wherein said amino alcohols include Di ethanol amine, 2 amino-2 methyl-1 propanol, ethanolamine capable of further reaction with cardanol derivative having oxirane group.
Preferably said cardanol polyol modified alkyds is provided wherein said drying/semi drying vegetable oils include Soya bean Oil, Dehydrated castor Oil, Linseed Oil, Tung Oil, Safflower seed Oil, sunflower Oil, Tall Oil, Cotton seed Oil, Rubber seed Oil and their fatty acids having iodine value in the range of 120-180 gI2/100g; dicarboxylic acid/anhydride includes phthalic anhydride, Isophthalic acid, Terephthalic acid, trimelliticanhydride, hexahydro phthalic anhydride, tetrahydro phthalic anhydride, maleic anhydride, succinic acid , adipic acid and preferably Phthalic anhydride; chain terminatingcycloaliphatic /aromatic carboxylic acid include benzoic acid, Para tertiary butyl benzoic acid, cyclohexane carboxylic acid, abietic acid (rosin) and preferably benzoic acid; polyols includetrimethylpentane diol, ethylene glycol, diethylene glycol,2-methyl-1,3-propanediol, 2-Butyl-2-Ethyl-1,3-Propanediol, neopentylglycol, glycerol, pentaerythritol, trimethylol ethane, trimethylol propane or similar and preferably pentaerythritol.
Advantageously, said cardanol polyol modified alkyds is provided having an acid number of <12 mg KOH/g preferably in the range of 5-10 mg KOH/g having clarity and viscosity of Y-Z, Z-Z4@ 54-56% Non Volatiles, and is MTO (mineral turpentine oil) thinnable adapted for metal glossy enamel as well as coating systems comprising primer & top coat providing said improved water, acid, alkali and Salt spray resistance properties.
Preferably said cardanol polyol modified alkyds is provided wherein said grafted cardanol polyol alkyd backbone involves amine functional cardanol polyol that partly substitutes said polyols in said alkyd backbone favouring said improved water, acid, alkali and Salt spray resistance properties.
According to another preferred aspect of the present invention there is provided said cardanol polyol modified alkyds wherein said grafted cardanol polyol alkydis a condensation product of 30-55 wt% drying / semi drying vegetable oils or their fatty acids having iodine value of 120-180 g I2/100g, 15-25 wt% polyols preferably pentaerythritol, 20-26 wt% dicarboxylic acid/anhydride preferably Phthalic anhydride,0.5-5% chain terminating mono functional acid preferably benzoic acid and 3-15 wt% cardanol-polyol having hydroxyl value of 150-350 mg KOH/g preferably of 225-275 mg KOH/g.
According to another aspect of the present invention there is provided a process for the manufacture of Cardanol polyol modified alkyds comprising the steps of
Providing cardanol polyol which ispolyhydroxy derivative of cardanol (cardanol-polyol) having hydroxyl value in the range of 150-350 mg KOH/g; and
Providing drying/semi drying vegetable oils or their fatty acids having iodine value in the range of 120-180 gI2/100g, aliphatic /aromatic carboxylic acid, aliphatic /aromatic carboxylic anhydride and polyols, in solvent and reacting until an acid number of <12 mgKOH/g is reached to obtain said cardanol polyol modified alkyds having hydroxyl value of 64-95 mg of KOH/g therefrom.
Preferably in said process for the manufacture of Cardanol polyol modified alkyds is obtained from following steps:
(i) Reacting 3-15 wt.% said cardanol polyol; with30-55wt% drying /semi drying vegetable oil or their fatty acids having iodine value of 120-180 g I2/100g, 15-25 wt% polyols preferably pentaerythritol, 20-26 wt% dicarboxylic acid/anhydride preferably Phthalic anhydride, 0.5-5% chain terminating acid preferably benzoic acid, 3-5% reflux solvent, taken into a four necked flask fitted with a stirrer, thermometer, nitrogen bubbler and Dean & Stark assembly for Azeotropic Distillation followed by slowing raise the batch temperature up to 200?C in 2-3 h with continuous removal of water of reaction;
(ii) Increasing the reaction temperature upto 245°C in 3-5 h until an acid value of <12 mg KOH/g is obtained;
(iii) Cooling the reaction mass to 130-170°C for thinning with MTO solvent at 55% solid and obtaining the resultant Cardanol polyol modified alkyds having acid value of 5-10 mg KOH/g and viscosity of Z-Z4 @ 54-56% Non Volatiles.
More preferably a process for the manufacture of Cardanol polyol modified alkyds is provided wherein said Reflux solvent is selected from methyl amyl ketone, xylene, Solvent CIX and preferably Xylene.
According to yet another preferred aspect of the present invention there is provided a process for the manufacture of cardanol polyol modified alkyds wherein when said alkyd is based on drying / semi drying Oil, said drying / semi drying Oil is charged together with part of polyol preferably pentaerythritol and dibutyl tin oxide and heated to 245-250?C to allow monoglyceride formation; followed by cooling the reaction mass to 180?C, followed by charging remaining ingredients including Pentaerythritol-II, Phthalic anhydride, benzoic acid, Cardanol triol of diethanol amine and Xylene for reflux and heated to 240-245?C in 3-5 hr and maintained till acid value of < 12 mg KOH/g is reached;
Cooling the reaction mass to 130-170°C and diluted with MTO solvent at 55% solid to get Cardanol polyol modified alkyds having acid value of 5-10 mg KOH/g and viscosity of Z1-Z2 @ 54-56% Non Volatiles.
Cardanol is a renewable material obtained from the distillation of Cashew Nut Shell Liquid at temperature in excess of 220?C under vacuum. This phenolic molecule has unique structure of having a long alkyl chain at meta position carrying unsaturation. Functional attributes of Cardanol have been exploited to derivatize series of value added products like phenolic resins, epoxy diluents, epoxy resins, phenalkamine hardeners etc for variety of end applications. In the present invention, a known derivative of Cardanol was synthesized by reacting epoxy functional Cardyl glycidyl ether and diethanol amine in controlled temperature conditions resulting in a tri hydroxy functional derivative of Cardanol being named as Cardanol triol of diethanol amine (CTDA). Surprisingly when the triple hydroxyl functionality of this molecule was involved in preparation of alkyd facilitated poly esterification reactions by part replacement of conventional polyols and could achieve enhanced corrosion resistance performance by virtue of presence of tertiary nitrogen and long alkyl chain with double bondsat meta position. In series of alkyd molecules thus synthesized, amine functional cardanol triol was incorporated at varying levels. The alkyds thus obtained were used to prepare white gloss paint and applied on bare steel at 45-55micron dry film thickness in 2 coats, air dried for 7 days and subjected to ASTM B 117 salt spray resistance to establish corrosion resistance performance.
Thus according to the basic aspect of the present invention there is provided cardanol polyol modified alkyds comprising amine functional cardanol polyol grafted into the alkyd backbone, said cardanol polyol being polyhydroxy derivative of cardanol having hydroxyl value in the range of 150-350 mg KOH/g.
Preferably said cardanol polyol modified alkyds is provided wherein said polyhydroxy derivative of cardanolincludes cardanol mono glycidyl ether reaction product ofamino alcohols.
More preferably said cardanol polyol modified alkyds is provided that is air drying and comprises a condensation product of polyhydroxy derivative of cardanol with drying/semi drying vegetable oils or their fatty acids, cycloaliphatic/aromatic carboxylic acid, cycloaliphatic /aromatic carboxylic anhydride and polyols adapted to impart hydrophobicity to the alkyd polymer back bone favouring enhanced water, acid, alkali and corrosion resistance characteristics.
According to yet another preferred aspect of the present invention there is provided said cardanol polyol modified alkyds wherein said amino alcohols include Di ethanol amine, 2amino-2 methyl-1 propanol, ethanolamine capable of further reaction with cardanol derivative having oxirane group.
Preferably said cardanol polyol modified alkyds is provided wherein said drying/semi drying vegetable oils include Soya bean Oil, Dehydrated castor Oil, Linseed Oil, Tung Oil, Safflower seed Oil, sunflower Oil, Tall Oil, Cotton seed Oil, Rubber seed Oil and their fatty acids having iodine value in the range of 120-180 gI2/100g; dicarboxylic acid/anhydride includes phthalic anhydride, Isophthalic acid, Terephthalic acid, trimelliticanhydride, hexahydro phthalic anhydride, tetrahydro phthalic anhydride, maleic anhydride, succinic acid , adipic acid and preferably Phthalic anhydride; chain terminatingcycloaliphatic /aromatic carboxylic acid include benzoic acid, Para tertiary butyl benzoic acid, cyclohexane carboxylic acid,abietic acid (rosin) and preferably benzoic acid; polyols includetrimethylpentane diol, ethylene glycol, diethylene glycol,2-methyl-1,3-propanediol, 2-Butyl-2-Ethyl-1,3-Propanediol,neopentylglycol, glycerol, pentaerythritol, trimethylol ethane, trimethylol propane or similar and preferably pentaerythritol.
According to another preferred aspect of the present invention there is provided said cardanol polyol modified alkyds having an acid number of <12 mg KOH/g preferably in the range of 5-10 mg KOH/g having clarity and viscosity of Y-Z, Z-Z4 @ 54-56% Non Volatiles, and is MTO (mineral turpentine oil) thinnable adapted for metal glossy enamel as well as coating systems comprising primer & top coat providing said improved water, acid, alkali and Salt spray resistance properties.
Preferably said cardanol polyol modified alkyds is provided wherein said grafted cardanol polyol alkyd backbone involves amine functional cardanol polyol that partly substitutes said polyols in said alkyd backbone favouring said improved water, acid, alkali and Salt spray resistance properties.
More preferably in said cardanol polyol modified alkyds wherein said grafted cardanol polyol alkydis a condensation product of 30-55 wt% drying / semi drying vegetable oils or their fatty acids having iodine value of 120-180 g I2/100g, 15-25 wt% polyols preferably pentaerythritol, 20-26 wt% dicarboxylic acid/anhydride preferably Phthalic anhydride,0.5-5% chain terminating mono functional acid preferably benzoic acid and 3-15 wt% cardanol-polyol having hydroxyl value of 150-350 mg KOH/gpreferably of 225-275 mgKOH/g.
According to another aspect of the present invention there is provided a process for the manufacture of Cardanol polyol modified alkyds comprising the steps of
Providing cardanol polyol which ispolyhydroxy derivative of cardanol (cardanol-polyol) having hydroxyl value in the range of 150-350 mg KOH/g; and
Providing drying/semi drying vegetable oils or their fatty acids having iodine value in the range of 120-180 gI2/100g, aliphatic /aromatic carboxylic acid, aliphatic /aromatic carboxylic anhydride and polyols, in solvent and reacting until an acid number of <12 mgKOH/g is reached to obtain said cardanol polyol modified alkyds having hydroxyl value of 64-95 mg of KOH/g therefrom.
Preferably in said process for the manufacture of Cardanol polyol modified alkyds is obtained from following steps:
(i) Reacting 3-15 wt.% said cardanol polyol; with30-55wt% drying /semi drying vegetable oil or their fatty acids having iodine value of 120-180 g I2/100g, 15-25 wt% polyols preferably pentaerythritol, 20-26 wt% dicarboxylic acid/anhydride preferably Phthalic anhydride, 0.5-5% chain terminating acid preferably benzoic acid, 3-5% reflux solvent, taken into a four necked flask fitted with a stirrer, thermometer, nitrogen bubbler and Dean & Stark assembly for Azeotropic Distillation followed by slowing raise the batch temperature up to 200?C in 2-3 h with continuous removal of water of reaction;
(ii) Increasing the reaction temperature upto 245°C in 3-5 h until an acid value of <12 mg KOH/g is obtained;
(iii) Cooling the reaction mass to 130-170°C for thinning with MTO solvent at 55% solid and obtaining the resultant Cardanol polyol modified alkyds having acid value of 5-10 mg KOH/g and viscosity of Z-Z4 @ 54-56% Non Volatiles.
Preferably in said process for the manufacture of Cardanol polyol modified alkyds said Reflux solvent is selected from methyl amyl ketone, xylene, Solvent CIX and preferably Xylene.
According to yet another preferred aspect of the present invention there is provided a process for the manufacture of Cardanol polyol modified alkyds wherein in case said alkyd is based on drying / semi drying Oil, said drying / semi drying Oil is charged together with part of polyol preferably pentaerythritol and dibutyl tin oxide and heated to 245-250?C to allow monoglyceride formation; as confirmed through compatibility test i.e. (Monoglyceride Sample: methanol ethanol mixture of 10+3) of 1: 3 minimum; followed by cooling the reaction mass to 180?C, followed by charging remaining ingredients including Pentaerythritol -II, Phthalic anhydride, benzoic acid, Cardanol triol of diethanol amine and Xylene for reflux and heated to 240-245?C in 3-5 hr and maintained till acid value of < 12 mg KOH /g is reached;
Cooling the reaction mass to 130-170°C and diluted with MTO solvent at 55% solid to get Cardanol polyol modified alkyds having acid value of 5-10 mg KOH/g and viscosity of Z1-Z2 @ 54-56% Non Volatiles.
It was surprisingly thus observed that alkyds obtained from the subject invention provided 600-650 hours of salt spray resistance directly on metal at a dry film thickness of 45-55 micronswhich is far superior over conventional alkyd basedcoatings providing 150-200 hours salt spray resistance at similar thickness.
Synergistic effect of long alkyl chain of unsaturated Oil / fatty acids coupled with presence of tertiary nitrogen and alkyl chain having unsaturation of cardanol triol when weaved into the alkyd backbone played key role in attaining superior corrosion resistance performance over conventional alkyds prepared using similar resin composition but without cardanol triol.
Thus the significant finding of the present invention was that paints based on the Cardanol triol modified alkyd of the present invention provided ASTM B117 salt spray resistance of minimum 600-650 hours wherein conventional alkyds failed within 150-200 hours when applied on direct to metal at samefilm thickness.

DETAILED DESCRIPTION OF THE INVENTION
As discussed hereinbefore, the present invention provides for cardanol polyol modified alkyds preferably air-drying alkyds involving cardanol polyols prepared by reaction of mono glycidyl ether of cardanol and amino alcohols like diethanol amine or similar having minimum one hydroxyl group. Reaction of oxirane ring of the mono glycidyl ether of cardanol with active hydrogen of the amino alcohols results in the opening of oxirane ring producing hydroxyl group, thereby providing at least 2 or more hydroxyls in the resultant molecule necessary for the synthesis of alkyds or polyesters. Said cardanol polyols when grafted onto the alkyd backbone could partly substitute commonly used polyols like Pentaerythritol, trimethylol propane, glycerine and similar to provide for the enhanced properties.
MTO thinnable cardanol polyol modified alkyd resin could be thus provided having excellent corrosion resistance and mechanical properties for direct to metal (Mild steel) applications.
It is thus a significant finding of the Applicants present invention that cardanol polyol (cardanol triol of Diethanol Amine) while is reported in literature and has been regularly employed for polyurethane applications, however, the present invention could uniquely provide for air-drying cardanol polyol modified alkydsand coating compositions thereof involving grafted cardanol triol into the alkyd backbone resulting in excellent corrosion resistance, which when employed in select amounts could enable part substitution of commonly used polyols including pentaerythritol, trimethylol propane, glycerine and similar polyols to provide excellent corrosion resistance properties and to obtain coating systems/compositions thereof.
Said cardanol-polyol-modified alkyd comprising a reaction product of polyhydroxy derivative of cardanol (cardanol-polyol) with drying/semi drying oils or their fatty acids, aromatic carboxylic acid, aromatic carboxylic anhydride and polyol could be thus provided imparting hydrophobicity to the alkyd polymer backbone for enhanced water and corrosion resistance characteristics.
Developed cardanol-polyol modified alkyd based coating composition is air-drying, MTO thinnable and can be directly applied on metal as a top coat with high gloss and excellent anti-corrosive properties.
Cardanol polyol modified alkyd resins were used for direct to metal glossy enamel as well as coating systems comprising of primer &top coat providing excellent corrosion resistance properties.
Thus by way of the present invention cardanol triol for alkyd synthesis is provided to enable air-drying cardanol polyol modified alkyds wherein said cardanol-polyol partly substitutes commonly used polyol favoring the synthesis of air-drying, MTO thinnable alkyd, thereby achieving enhanced water &corrosion resistance performance providing 600-650 hours of salt spray resistance in ASTM B117 at dry film thickness of 45-55 micron on bare mild steel.
Cardanol polyols substituting part of conventional polyols like Pentaerythritol, trimethylol propane, glycerol and similar polyols in alkyd synthesis thus surprisingly provides for cardanol polyol modified alkyds that reveals significantly high corrosion resistance performance (ASTM B 117 Salt Spray of 600-650 hr ) over conventional alkyds (ASTM B 117 Salt spray of 150-200hr) when applied directly on mild steel in 2 coats at dry film thickness of 45-55 microns.
Such air-drying cardanol polyol modified alkyds could be even prepared using Vegetable Oil Fatty acids as well as Vegetable Oil separately, involving different processes to reach to said alkyd. In case of vegetable oil-based process, monoglyceride route is preferred for further esterification with polyol / polybasic acid to attain the desired alkyd. Example No. 1 under Table 3 illustrates the use of soya bean oil.

Synthesis of Cardanol Triol:
Cardyl glycidyl ether having epoxide equivalent weight (EEW)of 450-625 was reacted with diethanol amine 98% in stoichiometric ratio (Epoxy Equivalent: Amine equivalent 1:1) to synthesize Cardanol triol of diethanol amine (CTDA). Reaction scheme of the same is depicted in Figure 1.
Table 1: Synthesis of Cardanol Triol of Diethanol Amine (CTDA):
Examples CTDA 001 CTDA 002
Ingredients involve using cardyl glycidyl ether at 2 different EEW and stoichiometric quantity of diethanol amine on equivalent basis as below Parts by Weight Parts by Weight
Cardyl glycidyl ether ( EEW509 ) 82.59 -
Cardyl glycidyl ether ( EEW 545 ) - 83.55
Diethanol Amine (98%), Amine Equivalent weight 107.28 17.41 16.45
Total 100 100

Process: Cardanol glycidyl ether and Diethanolamine as per Scheme 1 below were charged at ambient temperature of 20- 30?C in a four necked flask fitted with stirrer and thermometer. Reactants were heated to 40-42?C and stopped heating. Exothermic reaction observed resulting inincrease of temperature upto 74-80?C in a period of 2-3hrs. When exotherm subsided, reaction was allowed to continue at 80-90?C for 1 hour for completion. Thereafter vacuum was applied to remove traces of moisture and volatiles. The resultant Cardanol Triol was filtered through nylon cloth and packed.

Scheme 1

Table 2: Characteristics of Cardanol Triol of Diethanol Amine :
Batch No CTDA001 CTDA002
Colour On Gardner scale 14-15 12-13
Clarity Clear Clear
Viscosity at 25°C on Gardner Scale Y-Z X-Y
Hydroxyl Value (mg of KOH/gm) 269.8 267.3
Specific Gravity at 25?C 1.006 1.009
Refractive Index at 25?C 1.51593 1.51620
Table 3 : Synthesis of Cardanol Triol Modified alkyds :
Examples Alkyd 1 Alkyd 2 Alkyd 3 Alkyd 4 Alkyd 5 Alkyd 6
Soyabean Oil 47.05
Soya Oil Fatty Acid 0 45 43.5 42.57 40.2 48.26
Pentaerythritol 9.4 18.7 17.87 16.84 15.66 21.05
Pentaerythritol - II 5.66 0 0 0 0 0
Phthalic Anhydride 22.32 21.55 20.83 20.82 20.55 22.59
Benzoic Acid 3.11 2.7 2.6 2.37 1.94 2.05
Cardanol Triol of Diethanol Amine ( CTDA ) 6.00 6.00 8.7 11.35 15.6 0
Dibutyl tin oxide 0.05 0.05 0.05 0.05 0.05 0.05
Xylene for Reflux 6.41 6 6.45 6 6 6
Total 100 100 100 100 100 100
Dilute with Mineral Turpentine Oil (MTO) to 55% ,% NVM @120°C/ 1hr 55.65 55.7 55.5 55.34 55.45 55.50
Test Results
Colour on Gardner scale 14-15 14-15 16-17 >18 >18 4-5
Clarity Clear Clear Clear Clear Clear Clear
Viscosity @25°C on Gardner Scale Z1-Z2 Z-Z1 Y-Z Z2-Z3 Z3-Z4 Z1-Z2
Acid Value (mg of KOH/g) 9.9 9.89 7.5 7.8 10.16 2.31
Hydroxyl Value (mg of KOH/g) 92
67
88 75
64 90

Example 1 (Oil based Alkyd): Soyabeanoil, pentaerythritol and dibutyl tin oxide were charged in a four necked flask fitted with a stirrer, thermometer, nitrogen bubbler and Dean & Stark assembly for Azeotropic Distillation. Reaction mass was heated to 245-250?C for 1-2 hours for trans esterification reaction to form monoglyceride as determined through compatibility in ethanol methanol mixture. After completion of monoglyceride, remaining ingredients i.e. pentaerythritol-II, phthalic anhydride, benzoic acid, cardanol triol of diethyl amine (CTDA) and xylene reflux wereadded and reacted at 225-245?C to achieve an acid value of < 12 ( mg KOH /gm). Apply cooling to get temperature of < 170?C and dilute with MTO to achieve 55±1%non volatiles.
The above reaction works efficiently with other aminoalcohols within the scope of the invention and is also compatible with common polyols to generate cardanol polyol modified alkyds as long as the polyhydroxy derivative of cardanol has hydroxyl value in the range of 150-350 mg KOH/g.
The polyhydroxy derivative of cardanol are small molecules (adduct) formed by addition Reaction of amino alcohol and cardyl glycidyl ether unlike resins and above OH value range is the hydroxyl value obtained due to the presence of hydroxyl group (s) in amino alcohol plus creation of hydroxyl group due to reaction of active hydrogen attached to Nitrogen with Oxirane ring of Cardyl glycidyl ether. Such as in case of secondary amine alcohol, molar ratio would be 1 : 1 as with diethanol amine and cardyl glycidyl ether as stated in the example . If it a primary amine, molar ratio would by 1 mole of amino alcohol with 2 moles of cardyl glycidyl ether. In view of the aforesaid the hydroxyl value range is reached wherein said OH value is calculated by the equation of No. of OH groups X56100 / Molecular weight of the adduct. Considering the aforesaid -OH Value including ingredient variants employed the same is min at 150 and maximum of 350.
Examples 2 to 6 (Fatty Acid based Alkyds): Soya Oil Fatty acid, pentaerythritol, phthalic anhydride, benzoic acid, cardanol triol of diethyl amine (CTDA), dibutyl tin oxide and xylene reflux were charged into a four necked flask fitted with a stirrer, thermometer, nitrogen bubbler and Dean & Stark assembly for Azeotropic Distillation. Slowly raise batch temperature to 225-245?C with continuous removal of water of reaction. Monitor the batch foracid Value andwhen acid value reaches to< 12 (mg KOH/ gm), apply cooling for temperature of < 170?C and dilute with MTO to achieve 55±1% non volatiles.
Thus cardanol-polyol-modified alkyds comprising a reaction product of polyhydroxy derivative of cardanol (cardanol-polyol) with drying/semi drying oils or their fatty acids, aromatic carboxylic acid, aromatic carboxylic anhydride and polyol could be thus provided imparting hydrophobicity to the alkyd polymer back bone for enhanced water and corrosion resistance characteristics. Said cardanol-polyol-modified alkyds are derived from cardanol triol having hydroxyl value of 150-350mg KOH/g and more preferably 225-275 mg KOH/g; wherein the final hydroxyl value of the alkyd with cardanol polyol incorporation is in the levels of 65-95 mg of KOH/g.
According to another aspect, a process for the manufacture of cardanol-polyol modified alkyd resin is provided which involvescondensation reaction of 30-55 wt% of semi drying/drying vegetable oil or their fatty acids having iodine value of120-180 gI2/100g, 15-25 wt% polyols preferably pentaerythritol, 20-26wt% dicarboxylic acid/anhydride preferably Phthalic anhydride, 0.5-5% chain terminating mono functional carboxylic acid preferably benzoic acid and 3-15 wt% cardanol-polyol having hydroxyl value of 150- 350 mg KOH /g preferably of 225-275 mg KOH/g by heating in the temperature range of 170°C to about 250°C to obtain an acid number of 5-15 mg KOH/g of the thus formed alkyd resin.
Preferably, said cardanol-polyol is obtained by reacting monoglycidyl ether of cardanol and amino alcohols like Di ethanol amine, 2amino-2 methyl-1 propanol, ethanolamine etc in stochiometric ratios of their epoxy and amine equivalents at temperatures ranging from 40-90?C considering high reactivity of oxirane ring with active hydrogens of the respective amines.
Enamel Composition: Coating compositions comprising air drying cardanol-polyol modified alkyd as anti-corrosive binder in combination with coating ingredients include additives, anti-corrosive pigments, fillers, driers, diluents suitable as "one-pack" direct to metal enamel for ready to use composition for application.
Table 4: Pigmented Coating compositions
Raw materials Function Weight %
Premix Alkyd Resin(55%), Examples 1-6 Binder 13.00
Mineral turpentine Oil Solvent 2.07
Wetting agent EFCA 5207 Dispersing additive 0.40
Rheological clay additive Rheological additive 0.30

Pigment Mix Titanium Dioxide Pigment 22.50
Micronized Zinc Phosphate Anti corrosive pigment 0.50
Mixed on Hi speed using zirconium beads for finish 6.5 min on Hegmann Gauze, then stabilized and thinned.

Stabilization Alkyd Resin (55%), Examples 1-6 Binder 5.00
Mineral turpentine Oil Solvent 2.50

Thinning composition
Letdown Alkyd Resin (55%) Examples 1-6 Binder 38.22
Mineral turpentine Oil Solvent 11.26
Cobalt Octoate 5% Driers 0.25
Zirconium Octoate 18% Driers 0.70
Calcium Octoate 3% Driers 2.50
Borchi Oxy-coat1310 Driers 0.15
MEK Oxime Anti skin agent 0.10
Tinuvin 5060 UV absorber 0.05
Halox 550 WF Adhesion Promoter 0.50
Total 100

Testing of Enamels based on Cardanol-polyol modified alkyd:
Direct to Metal enamel paint was applied in 2 coats at dry film thickness of 45-55 micron on metal /glass panel and allowed to cure at ambient temperature for 7 days. Cured paint film showed gloss of >80 @20° on gloss head, hardness of 900-1000gmdry film thicknessand showedGood water resistance and Salt Spray resistance of 600- 650 hours as per ASTM B117.
Table 5: Paint Properties in White Enamel
Physical Properties Alkyd Exp 6 @ 0% CDTA Alkyd Exp 1& 2 @ 6% CDTA Alkyd Exp 3 @ 8.7% CDTA Alkyd Exp 4 @ 11.35% CDTA Alkyd Exp5 @ 15.6 % CDTA
Viscosity on FCB4@ 30°C 63 secs 59 secs 50 secs 96 secs 98 secs
%NVM @120°C/1hr 55.65 56.6 55.9 54.0 53.7
Gloss @20° 83 86 86 82 85
Drying Properties (In hours & Minutes)
Surface dry 2hr 10 mts 3hr 20mts 3hr 40mts 4hr 10mts 4hr 35mts
Tack free 6hr 8hr 8hr 8 hr 8hr
Hard dry 18hr 18hr 18hr 18 hr 18hr
Mechanical & Chemical Resistance : Applied 2 coats of film (For mechanical properties : Mild Steel panels & For Chemical Resistance : Glass Panels) & allowed to dry for 7 days at ambient temperature
Scratch hardness, g 1000 1000 1000 1000 900
Impact (90 cm, 2 Kg) passes Passes Passes passes Passes
Flexibility on ¼” Mandrel passes Passes Passes passes Passes
Coating immersed in water for 48 hr
Film Appearance
Gloss @20°
Gloss Retention %

No blisters
59.35
71.4

No blisters
68.63
79.8

No blisters
72.7
84.5

No blisters
75.15
91.6

No blisters
74.8
88.0
Coating immersed in 2% NaOH solution for 48 hr
Film Appearance
Gloss @20°
Gloss Retention %

No blisters
77.55
93.4

No blisters
81.9
95.2

No blisters
79.4
92.3

No blisters
79.35
96.7

No blisters
81.1
95.4
Coating immersed in 2% Sulphuric acid solution for 48 hr
Film Appearance
Gloss @20°
Gloss Retention %

No blisters
55.85
67.3

No blisters
79.1
91.9

No blisters
83.3
96.8

No blisters
72.2
88.0

No blisters
83.25
86.2

The above Table concludes that modified alkyd involving cardanol triol showed slower drying properties, but improved resistance with respect to gloss and gloss retention when immersed in water, acid and alkali solution.
Table 6: Salt Spray Resistance @ 2 coats on Mild Steel panels air dried for 7 days
Test / Criteria DTM-1 (0% Cardanol triol)
DTM-2 (6% Cardanol triol) DTM-3(8.7 % Cardanol triol) DTM-4 (11.35 % Cardanol triol) DTM-5 (15.6% Cardanol triol)
Salt spray resistance Set 1 Set 2 Set 1 Set 2 Set 1 Set 2 Set 1 Set 2 Set 1 Set 2
Dry Film thickness (microns) 42-46 44-46 43-46 48-50 42-43 41-45 41-45 47-49 43-46 45-46
ASTM B 117 Salt Spray, hr 200 200 640 640 640 640 640 640 640 640
Creepage from scribe(in mm) 4 4 4 4 1 1 2.5 2.5 1.5 1.5
Blisters Rating Dense Dense Medium Dense Medium Dense Few Few Medium Medium Medium Dense Medium Dense

It can be concluded from the ASTM B 117 Salt spray test results (Table 6) of the white Enamel coatings based on Alkyd examples 1 to 6 (Table 3) that incorporation of cardanol triol in the alkyd backbone significantly improved the corrosion resistance performance. Considering best Salt spray resistance performance, based on select levels of such incorporation of cardanol triol (CTDA) into the alkyd backbone that was found to be 8.7% out of the experimental alkyds involving 6-16% cardanol triol providing for desired clarity and viscosity in the levels of Y-Z , Z-Z4 measured at @25°C on Gardner Scale.