Title of Invention

"A PROCESS FOR PREPARATION OF HIGH PERFORMANCE CORROSION PROTECTIVE COATINGS"

Abstract

A process for the preparation of high performance corrosion protective coatings A process for the preparation of high performance corrosion protective coatings by preparing a base paint by dispersing the novel polymer alloy binder material in the range of 26.3 - 39.5 parts with a pigment mixture containing optionally rutile grade pigment selected from titanium dioxide, 0.0 - 18.6 parts, pigment red iron oxide, 0.0 - 15.4 parts, pigment zinc phosphate, 0.0 - 13.5 parts, pigment micaceous iron oxide, 0.0 - 19.3 parts, pigment middle chrome yellow, 0.0 - 4.6parts, extender pigment talc, 0.0 - 4.2 parts, extender pigment mica, 0.0 - 5.1 parts, extender pigment silica, 0.0 -4A parts, extender pigment whiting, 0.0 - 2.6 parts, extender pigment china clay, 0.0 - 6.1 parts, other conventional rhelogical additives to improve liquid paint properties not exceeding 0.13 - 0.46 parts to the total solids content of the liquid paint and mixture of organic solvents comprising aliphatic/aromatic hydrocarbons and ketones selected from n-butyl acetate, methyl isobutyl ketone, xylene, 80.0 -132.0 parts to obtain a base paint having a Fineness Value of 8-9, preparing isocyanate terminated urethane pre-polymer croslinking agent by reacting 0.8-1.40 moles of a low molecular weight polyhydroxy alcohol containing a tertiary carbon atom and preferably having the molecular formula C4-6H8-i602-5 in a suitable solvent mixture containing an aliphatic ketone, aromatic hydrocarbon and an aliphatic ester in the ratio of 1-1.3 : 0.8-1.7 : 0.2-1.3 with total

Full Text

The present invention relates to a naovol fomiulation use ful ar corrosion protective coating and a process fop the preparation of corrosion protective coatings-therefrom,. These new high performance corrosion protective coatings are based on a polymeric alloy binder material of epoxy-polyamide and polyurethane polymers. These corrosion protective coatings possess improved corrosion resistance, chemical resistance, weather resistance and improved mechanical properties. Hitherto only two types of two pack systems namely epoxy-polyamide and polyurethane which have the ability to form hard films through self-catalyzing reactions at ambient conditions have been extensively used in the field of corrosion protective organic coatings for the protection of metallic parts from corrosion. Each of these systems is made up of one individual polymeric component ( base resin ) being cured by the other pre-polymer component (otherwise called crosslinking agent/curing agent/hardener) to result in a crosslinked film for providing better corrosion protection than linear polymeric films such as chlorinated rubber, vinyls, thermoplastic acrylics etc. In the present case, instead of using an individual polymeric component (such as epoxy or acrylic), a novel polymer alloy material as described and claimed in our(copending) patent application NF a-235/98which is a polymer alloy of individual polymeric components namely epoxy, urethane and acrylate, is used. This alloy material is synthesized in such a way that during synthesis the individual polymeric molecules are entangled/interlocked physically and permanently like a woven fabric to form a network. This alloy material is subsequently mixed with an appropriate curing agent in a specified proportion along with pigments and other additives and applied over mild steel substrates to get protective coatings with improved film properties over that of the individual component polymers out of which the alloy is made. The films thus obtained exhibit interpenetration of the individual polymeric molecules and possess improved film properties such as corrosion resistance, chemical resistance, weather resistance and improved mechanical properties over that of the individual component polymers out of which they are made. The main object of the present invention is to provide a novel formulation useful as protective coating. Another object of the present invention is to provide a process for the preparation of high performance corrosion protective coatings using novel polymer alloys. Yet another object of the present invention is to prepare coatings by mixing the novel polymer alloy with an appropriate curing agent such as an isocyanate terminated urethane pre-polymer crosslinking agent along with suitably selected main pigments and extender pigments and other additives to get ambient cured films with improved corrosion resistance, chemical resistance, weather resistance, mechanical properties over that of the individual component polymers out of which it is made. Still another object of the present invention is to prepare coatings by mixing the novel polymer alloy with an appropriate curing agent such as an isocyanate terminated urethane pre-polymer crosslinking agent to get ambient cured films which can be used as a two-component binder material out of which a number of coating formulations, with suitably selected main pigments and extender pigments and other additives, can be developed which may be suitable to a wide variety of aggressive corrosive environments. Accordingly the present invention provides a novel formulation useful as corrosion protective coating which comprises a pigment mixture containing optionally rutile grade pigment titanium dioxide, pigment red iron oxide, pigment zinc phosphate, pigment micaceous iron oxide, pigment middle chrome yellow, extender pigment talc, extender pigment mica, extender pigment silica, extender pigment whiting, extender pigment china clay, other rheological additives such as Thixotropic Agent, Anti-settling Agent, Flow Control Agents etc. commonly used in paints to improve liquid paint properties and mixture of organic solvents comprising aliphatic/aromatic hydrocarbons and ketones such as n-butyl acetate, methyl isobutyl ketone, xylene.Accordingly, the present invention provides a process for the preparation of high performance corrosion protective coatings which comprises : i) preparing a base paint by dispersing the novel polymer alloy binder material such as herein described in the range of 26.3 - 39.5 parts with a pigment mixture containing optionally rutile grade pigment selected from titanium dioxide, 0.0 - 18.6 parts, pigment red iron oxide, 0.0 - 15.4 parts, pigment zinc phosphate, 0.0 - 13.5 parts, pigment micaceous iron oxide, 0.0 - 19.3 parts, pigment middle chrome yellow, 0.0 - 4.6parts, extender pigment talc, 0.0 - 4.2 parts, extender pigment mica, 0.0 - 5.1 parts, extender pigment silica, 0.0 -4.4 parts, extender pigment whiting, 0.0 - 2.6 parts, extender pigment china clay, 0.0 - 6.1 parts, other conventional rhelogical additives to improve liquid paint properties not exceeding 0.13 - 0.46 parts to the total solids content of the liquid paint and mixture of organic solvents comprising aliphatic/aromatic hydrocarbons and ketones selected from n-butyl acetate, methyl isobutyl ketone, xylene, 80.0 -132.0 parts to obtain a base paint having a Fineness Value of 8-9 ii) preparing isocyanate terminated urethane pre-polymer croslinking agent by reacting 0.8-1.40 moles of a low molecular weight polyhydroxy alcohol containing a tertiary carbon atom and preferably having the molecular formula C4-6H8-16O2-5 in a suitable solvent mixture containing an aliphatic ketone, aromatichydrocarbon and an aliphatic ester in the ratio of 1-1.3 : 0.8-1.7 : 0.2-1.3 with total isocyanate index 4500 - 5600 preferably along with 0.01-0.05 wt. % of an urethane catalyst in vacuum distilled methyl ethyl ketone and moisture & acid free butyl acetate at a temperature between 40-45°C for 15-20 minutes under constant stirring to result in a clear, turbid free, homogeneous solution and followed by the drop wise addition of nitrogen blown aliphatic/ aromatic diisocyanate of 2.7-3.6 molar times to a polyhydroxy alcohol containing a tertiary carbon atom and preferably having the molecular formula C4-6H8-16C2-5 under nitrogen atomosphere while maintaing the temperature between 50-55°C till the addition is completed and then raised to 70-75°C for about 15-25 minutes to complete residual polymerization followed by the addition of the said solvent mixture to adjust to required viscosity and the resulting turbid free, clear homogeneous resinous solution of isocyanate terminated urethane pre-polymer crosslinking agent is cooled, iii) mixing the prepared base paint obtained in step (i), 62.0 - 96.5 parts and isocyanate terminated urethane pre-polymer crosslinking agent obtained in step (ii), 11.2 - 38.5 parts to get corrosion protective coating. arts and isocyanate terminated urethane pre-po]ymfer crosslinking agent obtained in step (ii), 11 .2-38.5 parts to get the corrosion protective coating. The resultant liquid coating finally applying over sand/grit blasted mild steel specimens to cure for at least 7 days at ambient conditions to result in the High Performance Corrosion Protective Coatings which possess improved corrosion resistance, chemical resistance, weather resistance and improved mechanical properties as shown in table-II which are superior to that of the individual component polymers out of which the novel alloy binder material is made. Table-I Properties of Isocyanate Terminated Urethane Pre-polymer Crosslinking Agent (Table Removed) Table-II Performance Properties of High Performance Corrosion Protective Coatings (Table Removed) ru The solids content and the composition of the polymer alloy could well be adjusted to obtain still higher or lower dry film thickness. 2 Pass implies the minimum degree of the property the alloy possess and can be varied to increase or decrease In an embodiment of the present invention, the novel polymer alloy binder material used may be such asj.be novel alloy binder material prepared as reported in another patent by the authorsJP 235/QC In another embodiment of the present invention, the rutile grade pigment titanium dioxide used may be such as titanium dioxide having density 4.1. -4. 3, refractive index 2.6 -2.9 and passing 95% in a BS 350 sieve mesh. In yet another embodiment of the present invention, the pigment red iron oxide used may be such as natural/synthetic iron oxide preferably haematite having density 5.0 - 5.3, total soluble matter in water In yet another embodiment of the present invention, the pigment zinc phosphate used may be such as surface pretreated zinc phosphate having density 5.0 - 5.3, total soluble matter in water In yet another embodiment of the present invention, the pigment micaceous iron oxide used may be such as lamellar structured micaceous iron oxide having density 4.4 - 4.6, refractive index In yet another embodiment of the present invention, the pigment middle chrome yellow used may be such as yellow chrome pigment composed of PbCrO4 and PbSO4 in an approximate ratio of 82-95 : 5-18% by weight having density 5.58-6.04, refractive index In yet another embodiment of the present invention, the extender pigment talc used may be such as pigment grade talc (nagnesium silicate) having density 2.7 - 2.8, refractive index approximately 1.55 and passing 100% in a BS 350 sieve mesh. In yet another embodiment of the present invention, the extender pigment mica used may be such as pigment grade mica (silicate of aluminium and magnesium) having density 2.89, refractive index approximately 1.60. In yet another embodiment of the present invention, the extender pigment silica used may be such as pigment grade silica (silicon dioxide) having density 2.6 - 2.65, refractive index approximately 1.4 - 1.5 and passing 95 % in a BS 300 sieve mesh. In yet another embodiment of the present invention, the extender pigment whiting used may be such as pigment grade whiting (calcium carbonate) having density 2.7 - 2.8, refractive index approximately 1.5-1.6 and passing 95% in a BS 350 sieve mesh. In yet another embodiment of the present invention, the extender pigment china clay used may be such as pigment grade china clay having density 2.6 - 2.65, refractive index approximately 1.55 and passing 90% in a BS 300 sieve mesh. In yet another embodiment of the present invention, the isocyanate terminated urethane pre-polymer crosslinking agent used may be such as the reaction product of a low molecular weight polyhydroxy alcohol component such as trimethylol propane, polyethylene glycol -400, -600, -1000, polypropylene glycol -400, -600, -1000, polytetroxymethylene glycol -400, -600, -1000, pentaerithritol, glycerol etc. with an aromatic diisocyanate like toluene diisocyanate, diphenyl methane diisocyanate, napthalene diisocyanate, isophorone diisocyanate etc. along with urethane catalysts such as dibutyl tin dilaurate, diazobicyclooctane, zirconium oxychloride etc. Steps for the preparation of the high performance corrosion protective coatings using novel polymer alloys include (i) Preparing a base paint by dispersing the novel polymer alloy binder material prepared as reported in another patent by the authors, NF 235/98, 26.3 - 39.5 parts with a pigment mixture containing optionally rutile grade pigmenttitanium dioxide, 0.0 - 18.6 parts, pigment red iron oxide, 0.0 - 15.4 parts, pigment zinc phosphate, 0.0 - 13.5 parts, pigment micaceous iron oxide, 0.0 - 19.3 parts, extender pigment talc, 0.0 - 4.2 parts, extender pigment mica, 0.0-5.1 parts, extender pigment silica, 0.0 - 4.4 parts, extender pigment whiting, 0.0 - 2.6 parts, extender pigment china clay, 0.0 - 6.1 parts, other rheological additives such as Bentone-27, Thixin-R, Anti-settling Agent, Flow Control Agents commonly used in paints to improve liquid paint properties not exceeding 0.13 - 0.46 parts to the total solids content of the liquid paint and mixture of organic solvents comprising aliphatic/aromatic hydrocarbons and ketones such as n-butyl acetate, methyl isobutyl ketone, xylene etc., 80.0 - 132.0 parts to obtain a base paint having a Fineness Value of 8-9 as measured using a Hegmann Gauge, (ii). Preparing isocyanate terminated urethane pre-polymer crosslinking agent by reacting 0.8-1.4 moles of a low molecular weight polyhydroxy alcohol such as glycerol, trimethylol propane, pentaerithrital, polyethylene glycol -400, -600, -1000, polypropylene glycol -400, -600, -1000, poly tetroxymethylene glycol -400, -600, -1000, in a suitable solvent mixture containing n-butyl acetate, xylene and methyl ethyl ketone in the ratio of 1-1.3 : 0.8-1.7 : 0.2-1.3 with Total Isocyanate Index 4500 - 5600 to prepare a 51-69 % weight solids solution along with 0.01-0.05 wt. % of Diazobicyclooctane urethane catalyst in vacuum distilled methyl ethyl ketone and moisture & acid free n-butyl acetate at a temperature between 40-45°C for 15-20 minutes under constant stirring to result in a clear, turbid free, homogeneous solution and followed by the drop wise addition of a priorly nitrogen blown aliphatic/ aromatic diisocyanate such as isophorone diisocyanate/toluene diisocyanate 2.7-3.6 molar times to the polyhydroxy alcohol under nitrogen atmosphere while maintaining the temperature between 50-55°C till the addition is completed and then raised to 70-75°C for about 15-25 minutes to complete the residual polymerization followed by the addition of the said solvent mixture to adjust to required viscosity and the resulting turbid free, clear homogeneous resinous solution of isocyanate terminated urethane pre-polymer crosslinking agent is cooled and its properties are given in table-I. (iii). Mixing the prepared base paint obtained in step (i), 62.0 - 96.5 parts and isocyanate terminated urethane pre-polymer crosslinking agent as prepared in step (ii) having 58.0 - 72.0% weight solids content, 11.2 - 38.5 parts and (iv) Applying the liquid paint obtained in step (iii) over sand/grit blasted mild steel specimens of size 15x10 cm by brush/air spray/airless spray and allowed it to cure at ambient conditions for a period ofminimum 7 days to result in High Performance Corrosion Protective Coatings. The protective coatings thus obtained over mild steel substrates were subjected to various laboratory accelerated tests for their performance evaluation and the coatings were found to possess improved corrosion resistance, chemical resistance, weather resistance and improved mechanical properties over that of the individual component polymers out of which the novel polymer alloys are made. The properties of the coating are shown in table-II. The following examples are given by way of illustration of the present invention and should not be construed to limit the scope of the present invention. Example-1 (i). Dispersing the novel polymer alloy binder material prepared as reported in another patent by the authors, NF 235/98, 96.4 parts, pigment red iron oxide, 10.3 parts, pigment zinc phosphate, 12.0 parts, extender pigment talc, 3.4 parts, extender pigment mica, 5.4 parts, extender pigment silica, 3.4 parts, other rheological additives 2-methyl benzyl hydrogenated tallow ammonium bectorite as thixotropic agent, 0.05 parts, aluminium stearate as anti-settling agent, 0.17 parts, silicone oil having viscosity 300-340 cps as flow control agent, 0.13 parts by weight and mixture of organic solvents comprising n-butyl acetate, methyl isobutyl ketone, xylene in the ratio of 1:1.2:1.3, 59.5 parts to obtain a base paint having a Fineness Value of 8-9 as measured using a Hegmann Gauge, (ii). dissolving polyethylene glycol-1000, 41.0 parts in a solvent mixture comprising Xylene:Methyl isobutyl ketone:n-butyl acetate in a ratio of 1.5:1:1, 39.4 parts to a clear homogenous solution and followed by the addition of diazobicyclooctane 5.7 Wt % solution in a solvent mixture comprising xylene and methyl ethyl ketone in the ratio of 1:1, 0.7 parts and followed by heating the contents at a temperature of 45°C for 20 minutes and followed by dropwise addition of hexamethylene diisocyanate, 24 parts into the solution containing polyethylene glycol-1000 and maintaining the temperature at 55°C till the addition is complete and then raising the temperature to 75°C for about 20 minutes and followed by cooling the clear homogenous resinous solution and is kept as isocyanate terminated urethane pre-polymer crosslinking agent, (iii). Mixing the prepared base paint obtained in step (i), 92.0 parts and isocyanate terminated urethane pre-polymer crosslinking agent having 59.5 weightpercentage solids content, 26.7 parts and (iv). Finally applying the resultant liquid paint obtained in step (iii) over sand/grit blasted mild steel specimens of size 15x10 cm by brush/air spray/airless spray and allowed it to cure at ambient conditions for a period of minimum 7 days to result in High Performance Corrosion Protective Coating. The protective coating thus obtained over mild steel substrates was subjected to various laboratory accelerated tests for their performance evaluation and the coating was found to possess enhanced corrosion resistance, chemical resistance, weather resistance and improved mechanical properties over that of the individual component polymers out of which the novel polymer alloys are made. The performance behaviour of the title coating is shown in table-Ill. Table-Ill Performance Behaviour of High Performance Corrosion Protective Coating (Table Removed)Example-2Example-2 (i). Dispersing the novel polymer alloy binder material prepared as reported in another patent by the authors, NF 235/98, 81.6 parts, pigment micaceous iron oxide, 14.8 parts, extender pigment talc, 5.5 parts, extender pigment silica, 7.4 parts, extender pigment whiting, 3.7 parts, extender pigment china clay, 5.7 parts, other rheological additives 2-methyl benzyl hydrogenated tallow ammonium bectorite as thixotropic agent, 0.06 parts, aluminium stearate as anti-settling agent, 0.18 parts, silicone oil having viscosity 300-340 cps as flow control agent, 0.14 parts by weight and mixture of organic solvents comprising n-butyl acetate, methyl isobutyl ketone, xylene in the ratio of 1:1.2:1.3, 20.0 parts to obtain a base paint having a Fineness Value of 8-9 as measured using a Hegmann Gauge, (ii). dissolving polyethylene glycol-1000, 29.5 parts, trimethylol propane, 16.2 parts in a solvent mixture comprising Xylene:Methyl isobutyl ketone:n-butyl acetate in a ratio of 1.5:1:1, 44.0 parts to a clear homogenous solution and followed by the addition of diazobicyclooctane 6.8 Wt % solution in a solvent mixture comprising xylene and methyl ethyl ketone in the ratio of 1:1, 0.35 parts and followed by heating the contents at a temperature of 45'JC for 20 minutes and followed by the addition of diphenyl methane diisocyanate, 153 parts to the solution containing polyethylene glycol-1000 and trimethylol propane and maintaining the temperature at 55°C till addition is complete and then raising the temperature to 75°C for about 20 minutes and followed by cooling the clear homogenous resinous solution and is kept as isocyanate terminated urethane pre-polymer crosslinking agent, (iii). Mixing the prepared base paint obtained in step (i), 215.5 parts and isocyanate terminated urethane pre-polymer crosslinking agent having 69.0 weight percentage solids content, 21.5 parts and (iv). Finally applying the liquid paint obtained in step (iii) over sand/grit blasted mild steel specimens of size 15x10 cm by brush, air spray/airless spray and allowed it to cure at ambient conditions for a period of minimum 7 days to result in High Performance Corrosion Protective Coating. The protective coating thus obtained over mild steel substrates was subjected to various laboratory accelerated tests for their performance evaluation and the coating was found to possess enhanced corrosion resistance, chemical resistance, weather resistance and improved mechanical properties over that of the individual component polymers out of which the novel polymer alloys are made. The performance behaviour of the title coating is shown in table-IV.Table-IV Performance Behaviour of High Performance Corrosion Protective Coating (Table Removed)Example-3 (i). Dispersing the novel polymer alloy binder material prepared as reported in another patent by the authors, NF 235/98, 93.0 parts, pigment rutile titanium dioxide, 10.1 parts, pigment middle chrome yellow, 2.7 parts, extender pigment talc, 3.7 parts, extender pigment silica, 1.8 parts, extender pigment whiting, 1.6 parts, other rheological additives 2-methyl benzyl hydrogenated tallow ammonium bectorite as thixotropic agent, 0.11 parts, aluminium stearate as anti-settling agent, 0.21 parts, silicone oil having viscosity 300-340 cps as flow control agent, 0.10 parts by weight and mixture of organic solvents comprising n-butyl acetate, methyl isobutyl ketone, xylene in the ratio of 1:1.2:1.3, 46.5 parts to obtain a base paint having a Fineness Value of 8-9 as measured using a Hegmann Gauge, (ii). dissolving polytetroxymethylene glycol-600, 26.2 parts, trimethylol propane, 16.2 parts, in a solvent mixture comprising Xylene:Methyl isobutyl ketone:n-butyl acetate in a ratio of 1.5:1:1, 40.7 parts to a clear homogenous solution and followed by the addition of diazobicyclooctane 7.6 Wt % solution in a solvent mixture comprising xylene and methyl ethyl ketone in the ratio of 1:1, 0.6 parts and followed by heating the contents at a temperature of 45°C for 20 minutes and followed by the addition of hexamethylenediisocyanate, 102 parts into the solution containing polytetroxymethylene glycol-600 and trimethylol propane and maintaining the temperature at 55°C till addition is complete and then raising the temperature to 75°C for about 20 minutes and followed by cooling the clear homogenous resinous solution and is kept as isocyanate terminated urethane pre-polymer crosslinking agent, (iii). Mixing the prepared base paint obtained in step (i), 171.5 parts and isocyanate terminated urethane pre-polymer crosslinking agent having 65.0 weight percentage solids content, 17.5 parts and (iv). Finally applying the liquid paint obtained in step (iii) over sand/grit blasted mild steel specimens of size 15x10 cm by brush/air spray/airless spray and allowed it to cure at ambient conditions for a period of minimum 7 days to result in High Performance Corrosion Protective Coating. The protective coating thus obtained over mild steel substrates was subjected to various laboratory accelerated tests for their performance evaluation and the coating was found to possess enhanced corrosion resistance, chemical resistance, weather resistance and improved mechanical properties over that of the individual component polymers out of which the novel polymer alloys are made. The performance behaviour of the title coating is shown in table-V. Table-V Performance Behaviour of High Performance Corrosion Protective Coating (Table Removed)Example-4 (i). Dispersing the novel polymer alloy binder material prepared as reported in another patent by the authors, NF 235/98, 75.4 parts, pigment rutile titanium dioxide, 11.9 parts, pigment middle chrome yellow, 3.2 parts, extender pigment talc, 4.2 parts, extender pigment silica, 2.2 parts, extender pigment whiting, 1.2 parts, other rheological additives 2-methyl benzyl hydrogenated tallow ammonium bectorite as thixotropic agent, 0.08 parts, aluminium stearate as anti-settling agent, 0.19 parts, silicone oil having viscosity 300-340 cps as flow control agent, 0.11 parts by weight and mixture of organic solvents comprising n-butyl acetate, methyl isobutyl ketone, xylene in the ratio of 1:1.2:1.3, 32.6 parts to obtain a base paint having a Fineness Value of 8-9 as measured using a Hegmann Gauge, (ii). dissolving polyethylene glycol-600, 31.5 parts, glycerol, 6.9 parts, in a solvent mixture comprising Xylene:Methyl isobutyl ketone:n-butyl acetate in a ratio of 1.5:1:1, 36.8 parts to a clear homogenous solution and followed by the addition of diazobicyclooctane 7.5 Wt % solution in a solvent mixture comprising xylene and methyl ethyl ketone in the ratio of 1:1, 0.6 parts and followed by heating the contents at a temperature of 45°C for 20 minutes and followed by the addition of isophorone diisocyanate, 126 parts to the solution containing polyehthylene glycol-600 and glycerol and maintaining the temperature at 55°C till addition is complete and then raising the temperature to 75°C for about 20 minutes and followed by cooling the clear homogenous resinous solution and is kept as isocyanate terminated urethane pre-polymer crosslinking agent, (iii). Mixing the prepared base paint obtained in step (i), 86.5 parts and isocyanate terminated urethane pre-polymer crosslinking agent having 61.5 weight percentage solids content, 7.5 parts and (iv). Finally applying the liquid paint obtained in step (iii) over sand/grit blasted mild steel specimens of size 15x10 cm by brush/air spray/airless spray and allowed it to cure at ambient conditions for a period of minimum 7 days to result in High Performance Corrosion Protective Coating. The protective coating thus obtained over mild steel substrates was subjected to various laboratory accelerated tests for their performance evaluation and the coating was found to possess enhanced corrosion resistance, chemical resistance, weather resistance and improved mechanical properties over that of the individual component polymers out of which the novel polymer alloys are made. The performance behaviour of the title is shown in table-VI.Table-VI Performance Behaviour of High Performance Corrosion Protective Coating (Table Removed) The novelty of the present invention lies in i. Preparing the proper isocyanate terminated urethane pre-polymer crosslinking agent so as to react with the novel polymer alloy as obtained in another patent by the authors, NF 235/98 in the appropriate NCO/OH ratio so as to form hard films upon curing at ambient conditions through self-catalyzing reactions. ii. Ability of the above said two component system to achieve segmental interlocking within the polymer molecules so as to avoid the susceptibility to micro-separation of macromolecules on aging under aggressive conditions which is quite common with polymer blends systems where the blending of the polymer individual polymers is done through simple physical mixing. Proof for existence of interpenetration H.L.Frisch et al. (Pure. Appl. Chem., 53, 1557, 1981) and Edward.F. Cassidy et al., (J.Polym.Sci. Polym. Chem., 22, 1839-50, 1984) have extensively studied the glass transition behaviour and morphology of IPNs using electron microscopy. According to them, the existence of the interpenetration among the various networks in a polymer alloy can be established i. from the shift in dynamic glass transition temperatures of the IPNs incomparison to their corresponding homo-polyrners, pseudo-IPNs, linear polyblends and grafted-IPNs and ii. by using the scanning electron microscopy (SEM) where in the morphologies of the IPNs like phase mixing, phase domain sizes, sharpness etc. can be compared to their corresponding homo-polymers, pseudo-IPNs, linear polyblends and grafted-IPNs. All amorphous polymers have a glass transition temperature (Tg) depending upon the chemical nature of the polymer. Glass transition increases with increase in crosslink density. In the case of IPNs, the glass transition may be broadened or shifted depending upon the mixing of the polymer in the IPNs. In highly incompatible IPNs (which is highly phase-separated) each phase retains its individual glass transition temperatures. In the totally compatibilised IPNs where complete mixing takes place, only one transition is observed in the range between the glass transitions (Tgs) of the component polymers. Usually glass transition shifts inward from the individual components. But the observation of single glass transition temperatures (Tgs.) is an ideal condition and is seldom achieved in practice. In many cases, two distinct Tgs. as Tg1 and Tg2 ( in some cases more) which are always shifted inwardly than the Tgs of corresponding component networks have been reported confirming the existence of the interpenetration in the alloys according to the authors. In our case, table-VII shows the Tgs. of polymer alloys obtained from the DSC measurements with their component networks. It can be seen from table-VIII that the Tgs. of the alloys have shifted inwardly than the component networks confirming compatibilisation has occurred among the networks. Table-VII Tgs (in Kelvin) of IPNs & their homo-polymers (Table Removed)The morphology of IPNs (molecular orientation) is related to physical properties such as modulus and glass transition temperature (Tg) and provides an insight into the latter. The morphology of IPNs is controlled by chemical compatibility (solubility parameters), interfacial tension, crosslink densities, mode and kinetics of polymerization, and component types. The IPNs synthesized to date show different morphologies with varying degrees of phase separation, which is a complicated subject both theoretically and experimentally. Phases vary in size, shape, sharpness at the interfaces, and degree of continuity. IPNs can be classified based on morphology as having large structures with domain sizes of a few microns, intermediate structures with sizes around 1000 angstrom and no resolvable domain structures at all. In general, as phase domains become smaller, the systems become more compatible. Compatible IPNs mix on a molecular level with 5.0 nm domains, and semi-compatible IPNs from 5.0-30 nm and incompatible IPNs have domain sizes of 30 nm and greater, i.e. very coarse morphology. The SEM micrographs of the developed polymer alloys show the molecular mixing with phase sizes as small as in nm range confirming the presence of interpenetration within the alloys. The formulation prepared as claimed here are not mere admixture resulting in mere aggregation of the properties of indivisual ingredients but it is a synergistic mixture resulting in different properties of indivisual ingredients. The advantages of the present invention are: 1. The high performance corrosion protective coatings formulated using novel polymer alloy binder material possess improved corrosion resistance properties over those coatings based on the individual component polymers. 2. The high performance corrosion protective coatings formulated using novel polymer alloy binder material possess improved chemical resistance properties over those coatings based on the individual component polymers. 3. The high performance corrosion protective coatings formulated using novel polymer alloy binder material possess improved weather resistance (including ultra-violet rays)over the epoxy-polyamide based coatings and equal to aliphatic type polyurethane based coatings. 4. The high performance corrosion protective coatings formulated using novel polymer alloy binder material possess improved mechanical properties over those coatings based on the individual component polymers and the mechanical properties can still be tailor- made to requirements by manipulating the composition of alloying components to different ratios. 5. The high performance corrosion protective coatings formulated using novel polymer alloy binder material cure to form protective coatings at ambient conditions to provide film properties as shown in table-il. 6. Based on this coating material, different types of high performance protective coatings can be formulated to suit a variety of corrosive environments. 7. The presently used three coat corrosion protective coating system can effectively be substituted with a two coat corrosion protective coating system made up of the newly developed high performance corrosion protective coatings. 8. Besides the improvements in the film properties, as described above, this newly developed coating material is economical when compared to the epoxy-polyamide and aliphatic polyurethane based coatings. We claim: 1. A process for the preparation of high performance corrosion protective coatings which comprises : i) preparing a base paint by dispersing the novel polymer alloy binder material such as herein described in the range of 26.3 - 39.5 parts with a pigment mixture containing optionally rutile grade pigment selected from titanium dioxide, 0.0 - 18.6 parts, pigment red iron oxide, 0.0 - 15.4 parts, pigment zinc phosphate, 0.0 - 13.5 parts, pigment micaceous iron oxide, 0.0 - 19.3 parts, pigment middle chrome yellow, 0.0 - 4.6parts, extender pigment talc, 0.0 - 4.2 parts, extender pigment mica, 0.0 - 5.1 parts, extender pigment silica, 0.0 -4.4 parts, extender pigment whiting, 0.0 - 2.6 parts, extender pigment china clay, 0.0 - 6.1 parts, other conventional rhelogical additives to improve liquid paint properties not exceeding 0.13 - 0.46 parts to the total solids content of the liquid paint and mixture of organic solvents comprising aliphatic/aromatic hydrocarbons and ketones selected from n-butyl acetate, methyl isobutyl ketone, xylene, 80.0 -132.0 parts to obtain a base paint having a Fineness Value of 8-9 ii) preparing isocyanate terminated urethane pre-polymer croslinking agent by reacting 0.8-1.40 moles of a low molecular weight polyhydroxy alcohol containing a tertiary carbon atom andpreferably having the molecular formula C4-6H8-16C2-5 in a suitable solvent mixture containing an aliphatic ketone, aromatic hydrocarbon and an aliphatic ester in the ratio of 1-1.3 : 0.8-1.7 : 0.2-1.3 with total isocyanate index 4500 - 5600 preferably along with 0.01-0.05 wt. % of an urethane catalyst in vacuum distilled methyl ethyl ketone and moisture & acid free butyl acetate at a temperature between 40-45°C for 15-20 minutes under constant stirring to result in a clear, turbid free, homogeneous solution and followed by the drop wise addition of nitrogen blown aliphatic/ aromatic diisocyanate of 2.7-3.6 molar times to a polyhydroxy alcohol containing a tertiary carbon atom and preferably having the molecular formula C4-6H8-16O2-5 under nitrogen atomosphere while maintaing the temperature between 50-55°C till the addition is completed and then raised to 70-75°C for about 15-25 minutes to complete residual polymerization followed by the addition of the said solvent mixture to adjust to required viscosity and the resulting turbid free, clear homogeneous resinous solution of isocyanate terminated urethane pre-polymer crosslinking agent is cooled, mixing the prepared base paint obtained in step (i), 62.0 - 96.5 parts and isocyanate terminated urethane pre-polymer crosslinking agent obtained in step (ii), 11.2 - 38.5 parts to get corrosion protective coating.A process as claimed in Claims 1 to 13, the isocyanate terminated urethane pre-polymer crosslinking agent used is the reaction product of a low molecular weight polyhydroxy alcohol component trimethylol propane, polyethylene glycol - 400, 600, -1000, polypropylene glycol - 400, -600, - 1000, polytetroxymethylene glycol - 400, - 600, -1000, pentaerithritol, glycerol with an aromatic diisocyanate toluene diisocyanate, diphenyl methane diisocyanate, naphthalene diisocyanate, isophorone diisocyanate. 2. A process for the preparation of corrosion coatings there from substantially as herein described with reference to the examples.

Documents:

698-del-2000-abstract.pdf

698-del-2000-claims.pdf

698-del-2000-correspondence-po.pdf

698-del-2000-corresponence-others.pdf

698-del-2000-description (complete).pdf

698-del-2000-form-1.pdf

698-del-2000-form-19.pdf

698-del-2000-form-2.pdf

698-del-2000-form-3.pdf

698-del-2000-petition-138.pdf