MXPA99006079A - Newy polycarbodyimide polymers and their usocomo adhesive intermediate layers in automotive coatings - Google Patents

Abstract

The invention is directed to a block copolymer with the following representative structure, wherein: m = 1 to 20, n = 1 to 20, p = 0 or 1, R1 = a monomeric or polymer species containing only one functional group reactive with a group isocyanate. This species can also have another reactive functional group that is not reactive with a carbodiimide functionality such as an alkoxysilane. R2 = the radical of any available aliphatic, cycloaliphatic or aromatic diisocyanate. R3 = preformed polymer blocks such as a polyester, polyacrylate, polyurethane, polyether, polyethylene, polycarbonate, polyurea, polysiloxane, and the like. X = any combination of the present formulas (see formulas). The copolymer can be used in various automotive paint compositions. The resin can be prepared by first synthesizing the desired blocks, the polycarbodiimide blocks and modifying blocks, then bonding together. The resin can also be prepared by forming the polycarbodiimide directly towards the modification blocks. The last approach is preferred. Modification blocks are prepared in the conventional way for chemistry and the choice of modification blocks depends on the application. For proper wetting of topcoat, it is desired that some portion of the modification blocks be highly polar

Description

POLYCARBODIIMIDE POLYMERS NOVEDOSOS AND USE AS INTERMEDIATE ADHESIVE LAYERS IN AUTOMOTIVE COATINGS FIELD OF THE INVENTION This invention relates to a novel polycarbodiimide polymer. The use of this class of polymers results in coatings that provide an intermediate layer that is adhesive to both a wide variety of substrates and a number of coating technologies, particularly those technologies commonly used in automotive coatings. Automotive paint compositions, wherein the novel polycarbodiimide polymer has been found useful, include primer and salver compositions.

BACKGROUND The present invention is directed to novel polycarbodiimide compounds, their method of preparation, and their use in automotive compositions of environmental curing, of a package. It is often desirable to be able to apply various environmental curable coating technologies on the substrates typically found in a motor vehicle. These substrates could range from bare metal to plastics to the manufacturer's original equipment (OEM) coatings. Environmental curable coating technologies can vary from thermoplastic acrylic lacquers to air-oxidant alkyls to two-component acrylic urethanes to achieve this scale of substrate adhesion, an intermediate coating, also known as a "medium coating" or "mooring coat", is applied to the substrate before the top coating. This intermediate layer needs to be adherent to the substrate rather as the top coating will be effective. The middle coating it must also develop these adherent properties quickly in order to prevent tearing of the applied layer once the masking tape is removed in multi-layered or multi-tone applications and retain its adherent qualities even after being subjected to the exposure elements outside, such as temp high and low temperatures, high humidity conditions and ultraviolet radiation An ideal medium coating would also ensure proper adhesion to substrates that are properly prepared In addition to the above-mentioned properties, there are many desirable attributes of a medium coating adhesion promoter. adherent, the coating needs to be transparent and stable in color, so as not to affect the color of the substrate in cases where only a clear coating, a package, is applied for ease of use and retain its film integrity as a top coating that in many applications the adhesion promoter is applied beyond the repair area. Carbodumide compounds, particularly aliphatic carbodumides, are known to be reactive with a number of functional groups such as carboxyl amine, mercaptan epoxy, isocyanate and hydroxyl groups. appear frequently e on substrate surfaces and coating technologies This property, in addition to the excellent wetting behavior of carbodiimides prepared from typical isocyanates, makes them very suitable as vehicle primers. Carbodumide polymers are well known in the art as b in appropriate as a primer hardening component of two vehicle packages US Patent 4,118,536 describes the use of a carbodumide primer from a pack prepared exclusively from aromatic isocyanates and terminated with alkoxysilanes. Polycarbodumides prepared from aromatic isocyanates are generally raised in color and from ba] to reactivity. Additionally, undesirable UV-induced effects are common when the aromatic groups are conjugated with an isocyanate or the reaction products of isocyanates, probably due to the reaction of similar quinoid structures. Mixed aliphatic / aromatic polycarbodies can also be elevated. in color, depending on the relative amount of the aromatic component, require special processing and UV durability is suspected due to the justly mentioned reasons. The invention described herein has fast adhesion to a wide variety of substrates, does not necessarily require alkoxysilane to be Effective, it is a one package, transparent application, it is good to the weather and provides excellent moisture and final adhesion on a wide variety of worn and non-worn substrates.

COMPENDIUM OF THE INVENTION The invention is a coating comprised of a block copolymer with the following representative structure: Where: m = .1 n = .1 p = O or 1 Ri = A monomeric or polymeric species containing only one functional group reactive with an isocyanate group. This species may also have other reactive functional groups that are non-reactive with a carbodiimide functionality such as an alkoxy-syllable. R? = The radical of any available aliphatic, cycloaliphatic or aromatic protected diisocyanate. R3 = Preformed polymer blocks such as polyester, polyacrylate, polyurethane, polyether, polyethylene, polycarbonate, polyurea, polysiloxane or similar hybrids X = any combination of: 0 0 -C-N- -N-O-N- H H H 0 -N = C == N- or -S-C-N- H The resin can be prepared by first synthesizing the desired blocks, the polycarbodumide blocks and the modification blocks, then bonding them together. The resin can also be prepared by forming the polycarbodnmide directly. towards the modification blocks The last approach is preferred The modification blocks are prepared in the conventional way for the chemistry and the choice of the modification blocks depends on the application For proper upper coating wetting it is desired that some portion of the blocks of modification are highly polar After the polycarbodumide block is combined with the modification block the residual isocyanate groups are then plugged with a monofunctional modifier, which has a reactive isocyanate group. This blocking agent can be monomeric or polymeric in character and can be have an additional functional group that is unreactive with a car group bodumide, such as an alkoxy silane to further improve the performance of the coating The coating composition is then prepared by diluting the above-mentioned carbodiimide resin in appropriate solvents and combining additives such as creating a coating composition the non-volatile content of the formulation is keep it low to ensure that a thin layer is applied. The finished coating is applied through atomization of air to the substrate, followed by air drying then topcoating in the usual manner. The advantages provided by the invention is that when this resin is formulated to and applied with a medium coating adhesion promoter, imparts rapid adhesion of the final top coat to the substrate. This property will allow for problem-free derivation of the base coat in multilayer applications, where the tape edge release is importance This invention it also provides excellent moisture and final adhesion even after being subjected to external exposure elements such as cold temperatures, high humidity conditions and ultraviolet radiation, on a wide variety of worn and untrimmed substrates DETAILED DESCRIPTION OF THE INVENTION This invention herein is directed to polycarbonate compounds, their method of preparation and their use in a cross-linking composition. The use of this class of polymers provides an adhesive layer to a wide variety of substrates for a wide variety of layers of subsequent coatings, particularly automotive coatings. The invention is a coating comprised of a block copolymer with the following representative structure: Where: m = 2. 1 n = 2. 1 p = 0 or 1 Ri = A monomeric or polymeric species containing only one functional group reactive with an isocyanate group. This species may also have another functional reactive group that is non-reactive with a carbodiimide functionality such as an alkoxy silane. R2 = The radical of any available aliphatic, cycloaliphatic or aromatic diisocyanate. R3 = Preformed polymer blocks such as a polyester, polyacrylate, polyurethane, polyether. polyethylene, polycarbonate, polyurea, polysiloxane or similar hybrids, X = any combination of 0 0 -O-C- - or -N-C-N- or H H H O -N = C = N- O -S-C-N- H The resin can be prepared by first synthesizing the desired blocks, the polycarbodnide blocks and the modification blocks, then they are bonded together by their end groups. The resin can also be prepared by forming the polycarbodumide directly towards the modification blocks. The last approach is preferred. of modification are prepared in the conventional manner for chemistry and the selection of modification blocks depends on the application. For the appropriate wetting of the top coating, it is desired that some portion of the modification blocks be highly polar. Then the polycarbodumide block is combined with the modification block, the residual isocyanate groups are then capped with a monofunctional modifier, which has an isocyanate reactive group. This blocking agent can be monomepic or polymeric in character and can have an additional functional group that is non-reactive with an group car bodumide such as an alkoxy silane to further improve the performance of the coating The polycarbodnamide blocks of the invention can be prepared in a variety of ways In summary the methods described in US Patent No. 5 047,588 can be used when the carbodumides are prepared by the reaction of mono-di- and optionally tp-functional isocyanates with the simplest structures to conceptualize being based on ethylene-and dionesocyanates in the molar ratio of about 2 1 to about 2 10 mono- to dusocyanates to provide a carbodumide with the evolution of the carbon dioxide, using the following equation 2 R N C = O R - N = C N - R + CO, This process usually requires a catalyst and the preferred catalyst is in accordance with the patent 3-meth? Ll-phenol-2-phospholene-1-oxido In the preferred synthetic process a reaction vessel equipped with a heating element and one of cooling, condensing agitation and a subsuperfícial purge of inert gas, is charged with chlorinated, aliphatic or aromatic protected dnsocyanate and any modification blocks. The mixture is then heated to 60-80 g and maintained until the functional groups in the Modification blocks are completely consumed by the isocyanate. If a blocking agent is a functional isocyanate compound, a stoichiometric amount is also loaded at this stage. The aliphatic and cycloaliphatic monolamino and polyacrylates include butyl isocyanate, cyclohexyl isocyanate, octadecyl isocyanate 1 -tetramet? lhexamet? lend? soc? anato 1 6-hexand soc? a-nato, l "12-dodecaned? soc? anato 2,4- and 2 4 4-t r? met? l -hexamethylenediazienate 1 4-c? clohexared? soc? anato b? s (4-? soc? anatoc? clohex?) methane, isophoronadnsocyanate dipentendusocynate Protected aromatic polusocyanates include meta- and para-tetramethylelylenedisocrate Even when these isocyanate compounds have an aromatic character, the isocyanate groups are removed from the aromatic ring and are protected by saturated carbon atoms. As expected, these isocyanate compounds behave as aliphatic isocyanates in reactivity and properties. Exemplary modification blocks would include polyether diols, polyacrylate diols, or thioglycerol-terminated acrylonitrile polyacrylates, polyurethane diols, polyether diols or diamines, polyethylene / butylene diols, polycarbonate diols, polyurea diamines, diols or diammas of polysiloxane or similar hybrids Solvents can be used in the synthesis to reduce the viscosity of the reaction mass. Suitable solvents are those which are non-reactive with said aromatic hydrocarbons, aliphatic esters, glycol ether esters, diesters or glycol ketones, if not primary amines are used in the synthesis. The solvent must have a sufficient boiling point to allow the preferred reaction temperatures. The catalyst is usually introduced into a non-reactive solvent, dry, such as xylenes. The preferred catalysts, due to efficiency and availability reasons, is 3-methyl-1-phenyl-2-phofol-na-1-oxide at levels between 0.1 and 1.5 mole%. The reagents are heated to 140-170BC with a purge of inert gas, typically nitrogen, to facilitate the loss of CO 2 and maintain at that temperature until the isocyanate percentage value is within the desired value. The isocyanate conversion can be monitored using the ASTM method D-11638-74 NCO titration Released C02 can also be trapped and measured as an indication of conversion extension. Once the desired conversion level has been reached if the plugging agent is not an isocyanate compound, the mixture it is then cooled to 60-75 ° C and the stopper agent is introduced. Suitable non-isocyanate stoppers would include monofunctional alcohols mercaptans amines, aminoalkylalkoxy silanes. These monofunctional compounds could be monomeric or polymeric in composition. The content of the reactor is maintained at 60-75sC until the isocyanate is no longer detected In some cases, it may be necessary to increase the temperature at 140-170aC or add an excess of plugging agent to ensure that the isocyanate groups are completely consumed The progress of the reaction can be monitored with an infrared spectrometer, observing the emergence of the carbodumide ridge (at approximately 2125 cm "1) and the disappearance of the isocyanate ridge (at approximately 2260 era1) The coating is prepared by diluting the polycarbodnide resin in appropriate solvents and combining additives such as UV absorbers, silicones, plasticizers, etc., to create a coating composition. Volatile coating composition is kept low (less than 25% non-volatile) to ensure a thin film after application DESCRIPTION OF THE PREFERRED MODALITIES The following examples illustrate the invention in various useful embodiments, but are not intended to limit the invention in any way.

EXAMPLE 1 A one-liter, four-necked flask equipped with a condenser, stirrer, thermocouple, and subsurface nitrogen inlet was charged with 204 grams of isophorone dusocyanate, 24.4 grams of m-tetramethyl-x-yl-2-adidocyanate, and 5 grams of xylenes. stirring a mixture of 34 3 grams of aminopropyl-p-methoxysilane and 92 1 grams of xylenes was uniformly added over one hour to 1 3 grams of a 30% solution of 3-meth? ll-phen? -l-2-for-folma-1-x? The xylenes were charged and the mixture was heated to an initial reflux temperature of 166flC. The mixture was refluxed about 12 5 hours until a isocyanate percent value of 1.0% was obtained (ASTM method D-11638-74 NCO titration). The mixture was then cooled to 70-80BC and charged to the flask. 7 9 grams of benzyl alcohol and 179 8 grams of methyl butyl ketone The mixture was then kept at 70-80 aC about sixteen hours until an omissable NCO percent value was obtained. The mixture is then cooled to ambient temperatures and discharged.

EXAMPLE II A one-liter, 4-neck flask equipped with a condenser, stirrer, thermocouple, and subsurface nitrogen inlet was charged with 237 5 gms of isophorone dusocyanate 12 5 gms of m-tetramethylxylene dusocyanate, and 57 3 xylenes gms Under stirring, a mixture of 37 5 gms of a polypropylene oxide diamine polymer (under the trademark JEFFAMINE (R) D-400) and 42 5 gms of xylenes was added evenly over a mixture of 375 gms of aminopropyltri ethoxysilane and 73 9 gms of xylenes was added evenly for two hours to 2 g 6 of a 305 solution of 3-met l-1-pheny1-2-phosphol ma-1-oxid in xylenes were then charged and the mixture was heated to an initial reflux temperature of 157BC. The mixture is refluxed until a isocyanate percent value of 1 90% is obtained (ASTM method D-11638-74 NCO titration). The mixture is then cooled to 60-70gC and 210 gms of methyl isobutyl ketone and 26 4 gms of di-n-butylamine are added L The mixture is then cooled to ambient temperatures and discharged EXAMPLE III A one-liter, 4-necked flask equipped with a condenser, agitator, thermocouple and subsurface nitrogen inlet was charged with 237 5 gms of isophorone dusocyanate, 12 5 gms of m-tetramethylxylene dusocyanate, and 57 3 gms of xylenes 27.0 gms of 2-hydroxyl and? lyrrolidoneone and 0.3 gms of a 1% solution of dibutyltin dilaurate in xylenes were added and the mixture was heated to 60.degree. 752C until a constant isocyanate percent value was obtained To the flask, a mixture of 37 5 gms of a polypropylene oxide diamine polymer (under the trademark JEFFAMINE (R) D-400) was uniformly added over two hours and 116 4 xylenes 7 89 gms of a 10% solution of 3-meth? Ll-phenol-2-phosphol? Na-1-oxide in xylenes was then charged and the mixture heated to a reflux temperature initial 151aC The mixture is refluxed until a isocyanate percent value of 1 95% is obtained (ASTM method D-11638-74 NCO titration). The mixture was then cooled to 60-75 aC and 166 g of methyl isobutyl ketone and 24 g of din-n-butylamma were added. The mixture was then cooled to ambient temperatures and discarded.

EXAMPLE IV A one-liter four-necked flask equipped with a condenser, a thermocouple stirrer and subsurface nitrogen inlet was charged with 237 5 gms of isophorone dusocyanate, 12 gms of m-tetramethylxylene dusocyanate, 70 gms of hydrogenated polybutadiene (under the brand name KRATONÍR) L-2203 from Shell Chemical Co) and 98 2 gms of xylenes The mixture was heated to 60-75aC until a constant isocyanate percent content was reached A mixture was added evenly for two hours of 33 1 gms of ammopropyltrimethoxysilane and 25 2 gms of xylenes Then 3 9 gms of a 105 solution of 3-meth? ll-phen? l-2-phosphol-1-x-oxide in xylenes were charged and the mixture heated to an initial reflux temperature of 168aC. The mixture was refluxed until a isocyanate percent value of 0 5% was obtained (ASTM method D-11638-74 NCO titration). The mixture was then cooled to 60-70 ° C. and 87 gms of methylisubutyl ketone were added. Then 114 were added. 5 gms of 2-propanol and the mixture is - 11 heated to reflux at about 88-92aC and maintained until no residual isocyanate groups were detected. The mixture was then cooled to ambient temperatures, 100 gms of 2-propanol was added and the batch was dispensed.

EXAMPLE V In order to demonstrate the present invention, coatings formulations were prepared from Examples I-IV by diluting each resin with a mixture of , solvent with the following composition Methyl Isobutyl Ketone 49 0% N-Butyl Acetate 49 0% Ethyl 3-Ethoxy-Propioate 2 0% up to about 5% non-volatile content coatings were applied through air atomization to panels that were precoated with appropriately cured OEM basecoat and clearcoat finish. Each coating was allowed to air dry approximately - Q fifteen minutes before an automotive finish basecoat was applied over the intermediate layers The base coatings were allowed to dry for thirty minutes. The initial adhesion was tested by scratching an "X" on the coated panel, placing a piece of adhesive tape on the scratch and evenly pulling the scratch cap All the test coatings had improved adhesion compared to the control, a refinished basecoated panel without intermediate layer. A portion of these panels were also coated with transparent. The clear coatings were allowed to cure for seven days, then subjected to 100% relative humidity at 43 ° C for 96 hours. The adhesion was tested as before with all test coatings having improved adhesion compared to the control, a panel coated with refinishing base and coated with transparent without intermediate layer.

Claims (4)

1. CLAIMS 1 - . 1 - A novel polycarbodumide polymer of the structure where m = 2. 1 n = 2, 1 p = 0 or 1 Rt = a monomorphous or polimépca species containing only one functional group reactive with an isocyanate group This species may also have another reactive functional group that is not reactive with the carbodiimide functionality such as an alkoxy silane R2 = the radial of any available aliphatic cycloaliphatic or aromatic protected dnsocyanate R3 = preformed polymer blocks such as polyester plate, polyurethane, polyether, polyethylene polycarbonate, polyurea polysiloxane or similar hybrids, X = any combination of OOH -OCN- or -NCN- HHH 0 - = C == N- or -S-C- - H 2 - An automotive paint composition comprising a polycarbodumide polymer of the structure where m = 2. 1 n =. 1 p = 1 or 2 x = a monomeric or poly epic species that contains only one functional group reactive with an isocyanate group This species may also have another reactive functional group that is not reactive with a carbodi? Ed functionality such as an alkoxy silane R2 = The radical of any aliphatic cycloalkyl fatico or aromatic protected dusocyanate available R3 = Blocks d? preformed polymers such as polyester polyacrylate, polyurethane, polyether, polyethylene polycarbonate, polyurea polysiloxane or similar hybrids X = any combination of 0 0 -O-C-N- or -N-C-N- or H H H 0 - • N = C == N- or -SCN- H 3 - The paint composition of claim 2, wherein the paint composition is a primer composition 4 - The paint composition of claim 2 wherein the Paint composition is a sealing composition SUMMARY OF THE INVENTION The invention is directed to a block copolymer with the following representative structure: where: m = 1 to 20 n = 1 to 20 p = 0 or 1 Ri = A monomeric or polymeric species containing only one functional group reactive with an isocyanate group This species may also have another reactive functional group that is not reactive with a carbodiimide functionality such as an alkoxy silane R2 = The radical of any available aliphatic, cycloaliphatic or aromatic diisocyanate. R3 = Preformed polymer blocks such as a polyester, polyacrylate, polyurethane, polyether, polyethylene, polycarbonate, polyurea polysiloxane or similar hybrids. X = any combination of: O O p > ? -O-C-N- or -N-C-N- or H H H 0 -C = C = N- or -SC- - H The copolymer can be used in various automotive paint compositions The resin can be prepared by first synthesizing the desired blocks, the polycarbodumide blocks and modifying blocks, then bonding together. The resin can also be prepare by forming the polycarbodumide directly into the modification blocks The last approach is the preferred The modification blocks are prepared in the conventional way for the chemistry and the choice of modification blocks depends on the application For proper wetting of top coating, it is desired that some portion of the modification blocks are highly polar